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  • 151.
    Aijaz, Asim
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, The Institute of Technology.
    Sarakinos, Kostas
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, The Institute of Technology.
    Lundin, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, The Institute of Technology.
    Brenning, Nils
    Royal Institute of Technology.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, The Institute of Technology.
    A strategy for increased carbon ionization in magnetron sputtering discharges2012In: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 23, p. 1-4Article in journal (Refereed)
    Abstract [en]

    A strategy that facilitates a substantial increase of carbon ionization in magnetron sputtering discharges is presented in this work. The strategy is based on increasing the electron temperature in a high power impulse magnetron sputtering discharge by using Ne as the sputtering gas. This allows for the generation of an energetic C+ ion population and a substantial increase in the C+ ion flux as compared to a conventional Ar-HiPIMS process. A direct consequence of the ionization enhancement is demonstrated by an increase in the mass density of the grown films up to 2.8 g/cm3; the density values achieved are substantially higher than those obtained from conventional magnetron sputtering methods.

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  • 152.
    Holmgren, Johan
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A strategy for increased public transport usage: The effects of implementing a welfare maximizing policy2014In: Research in Transportation Economics, ISSN 0739-8859, E-ISSN 1875-7979, Vol. 48, p. 221-226Article in journal (Refereed)
    Abstract [en]

    For a long time public transport has experienced a struggle against rising costs and increasing car ownership. So far, public transport appears to be on the losing side in terms of market shares. The aim if this paper is to investigate if a different policy could result in higher public transport usage and improved social welfare. In order to achieve this, a model, explaining public transport usage, public transport supply and costs, is estimated. The model is then used in order to simulate the outcome of an alternative policy of social welfare maximization. It is found that the current policy of the Swedish transport is not efficient in terms of maximizing welfare. In 2011, public transport fares should have been lower in 20 of 21 counties and the supply of vehicle kilometres should have been higher in 17 of 21 counties. Implementing a welfare maximizing policy would have increased the number of trips per capita by 17.2% in 2011 and by an average of 6.7% for the period 1986-2011.

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  • 153.
    Holmgren, Johan
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A strategy for increasing public transport market share : an investigation of an alternative development2013In: Thredbo 13 - The 13th International Conference on Competition and Ownership in Land Passenger Transport, 2013Conference paper (Other academic)
    Abstract [en]

    Fora long time public transport has experienced a struggle against rising costsand increasing car ownership. So far, public transport appears to be on the losingside in terms of market shares. The aim if this paper is to investigate if adifferent policy could result in higher public transport usage and improvedsocial welfare. In order to achieve this, a model, explaining public transportusage, public transport supply and costs, is estimated. The model is then usedin order to simulate the outcome of an alternative policy of social welfaremaximization. It is found that the current policy of the Swedish transport isnot efficient in terms of maximizing welfare. Implementing a welfare maximizingpolicy would have increased the number of trips per capita by 12.5 per cent in2011.

  • 154.
    Olsson, Anna
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Sundström, Torbjörn
    Umeå universitet .
    Larsson, Anne
    Umeå universitet .
    Sandborg, Michael
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Gustafsson, Agnetha
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    A strategy for optimisation of nuclear medicine examinations – application to rCBF SPECT2010Conference paper (Other academic)
  • 155.
    Taxén, Lars
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology. Ericsson Utvecklings AB.
    A Strategy for Organisational Knowledge Evolution1999Conference paper (Refereed)
    Abstract [en]

    In this paper, a strategy for organisational knowledge evolution is presented. Organisational knowledge is defined as knowledge concerning the management of the artefacts provided by the organisation. The strategy is derived from a theoretical, action-oriented representation of knowledge and uses concrete instruments for iterating between reflection and action. The instruments for reflection are conceptual models and information flow diagrams. The instrument for action is an object oriented information management system, where the models are implemented and tried out in practise. By applying these instruments iteratively, organisational knowledge is generated, both as individual and shared knowledge among the actors, as well as objectified knowledge represented by the models and the implemented information management system. We describe how this strategy has been used at the Ericsson telecommunication company to handle the transition to a new software development model. The transition was complicated by the fact that Ericsson has many designers (more than 10 000) working at local design centres all over the world. Our experience shows that the proposed strategy is a powerful way to quickly acquire, deploy and manifest new organisational knowledge

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  • 156.
    Backenius, Erik
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Vesterbacka, Mark
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Hägglund, Robert
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A strategy for reducing clock noise in mixed-signal circuits2002In: Proc. IEEE 45th Midwest Symp. on Circuits and Systems, MWSCAS'02, 2002, Vol. 1, p. 29-32Conference paper (Refereed)
    Abstract [en]

    Digital switching noise is of major concern in mixed-signal circuits due to the coupling of the noise via a shared substrate to the analog circuits. A significant noise source in this context is the digital clock network that generally has a high switching activity. There is a large capacitive coupling between the clock network and the substrate. Switching of the clock produces current peaks causing simultaneous switching noise (SSN). Sharp clock edges yields a high frequency content of the clock signal and a large SSN. High frequency noise is less attenuated through the substrate than low frequencies due to the parasitic inductance of the interconnect from on-chip to off-chip. In this work, we present a strategy that targets the problems with clock noise. The approach is to generate a clock with smooth edges, i.e. reducing both the high frequency components of the clock signal and the current peaks produced in the power supply. We use a special digital D flip-flop circuit that operates well with the clock. A test chip has been designed where we can control the rise and fall time of the clock edges in a digital FIR filter, and measure the performance of a fifth-order analog active-RC filter.

  • 157.
    Carlsson, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics . Linköping University, The Institute of Technology.
    Wedell, Anna
    Department of Molecular Medicine and Surgery, CMM:02, Karolinska Institutet/Karolinska University Hospital, SE-171 76 Stockholm, Sweden.
    Persson, Bengt
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics . Linköping University, The Institute of Technology.
    A structural model of human steroid 11-betahydroxylase,CYP11B1, used to predict consequences of mutations2009Article in journal (Other academic)
    Abstract [en]

    A prediction method has been developed to estimate the severity of amino acid residue exchanges in human steroid 11-beta-hydroxylase, CYP11B1, due to mutations in the corresponding gene. The prediction is based both on structural and on sequence dependent parameters. The method uses two approaches; one with general molecular property weights and one with a consensus voting strategy based upon distribution of molecular properties, which does not require any training. Both methods are tested on known mutations in CYP11B1 and result in 85% prediction accuracy. The consensus voting method is then further evaluated on 9 proteins with an average of 81% prediction accuracy. A server utilizing the results from the consensus voting on CYP11B1 is provided where the user can extract information about new mutants. A similar server is also provided for mutants in human steroid 21-hydroxylase (CYP21).

  • 158.
    Shah, Fahid
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Sindakovski, Robert
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    A study about Social Media Marketing for Local Grocery Stores: How Social media can be used to create a better customer relationship?2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The role of internet and the digitalized world are more relevant than ever before. The new phenomena of digital marketing has created a paradigm shift of existing marketing with new ways to market. Social media plays a significant role in this change, since it allows businesses to easily engage with its customers and to maintain relationships. For small and local businesses, this change has created great opportunities to interact more with the local audience. However, not all such businesses have the sufficient knowledge to optimize the usage of social media.

    The focus of the study is to explore the current usage of social media in local businesses context. Furthermore, we will suggest social media marketing strategies that will help local business to improve its customer relations. The qualitative approach is applied in this study by using interviews and observations, which is the main source of primary data collection. The conclusion was that local grocery stores still rely much more on traditional marketing methods. However, local grocery stores still use and value social media, but most are unclear of the true benefits and strategies when using social media. Lacking strategies consist of planning the social media marketing strategies, but also lacks the formal management of critical situations on social media. Overall, local stores perform well in building relations with its customers using social media however, there is a scope of further improvements.

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  • 159.
    Pant, Prabhat
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Salvemini, Filomena
    ANSTO, Australia.
    Proper, Sebastian
    RISE IVF AB, Sweden.
    Luzin, Vladimir
    ANSTO, Australia; Univ Newcastle, Australia.
    Simonsson, Kjell
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Sjöström, Sören
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Hosseini, Seyed
    RISE IVF AB, Sweden.
    Peng, Ru
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    A study of the influence of novel scan strategies on residual stress and microstructure of L-shaped LPBF IN718 samples2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 214, article id 110386Article in journal (Refereed)
    Abstract [en]

    Process parameters in laser-based powder bed fusion (LBPF) play a vital role in the part quality. In the current study, the influence of different novel scan strategies on residual stress, porosities, microstructure, and crystallographic texture has been investigated for complex L-shape parts made from nickelbased superalloy Inconel 718 (IN718). Four different novel scanning strategies representing total fill, re-melting, and two different sectional scanning strategies, were investigated using neutron diffraction, neutron imaging, and scanning electron microscopy techniques. These results were compared with the corresponding results for an L-shape sample printed with the conventional strategy used for achieving high density and more uniform crystallographic texture. Among these investigated novel strategies, the re-melting strategy yielded approximately a 25% reduction in surface residual stress in comparison to the reference sample. The other two sectional scanning strategies revealed porosities at the interfaces of the sections and due to these lower levels of residual stress were also observed. Also, variation in crystallographic texture was observed with different scan strategies.

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  • 160.
    Berglund, Eva
    et al.
    Uppsala Univ, Sweden.
    Barbany, Gisela
    Karolinska Inst, Sweden; Karolinska Univ Hosp, Sweden.
    Orsmark-Pietras, Christina
    Div Lab Med, Sweden; Lund Univ, Sweden.
    Fogelstrand, Linda
    Sahlgrens Univ Hosp, Sweden; Univ Gothenburg, Sweden.
    Abrahamsson, Jonas
    Queen Silv Childrens Hosp, Sweden.
    Golovleva, Irina
    Univ Umeå, Sweden.
    Hallböök, Helene
    Uppsala Univ, Sweden.
    Höglund, Martin
    Uppsala Univ, Sweden.
    Lazarevic, Vladimir
    Skåne Univ Hosp, Sweden.
    Levin, Lars-Åke
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Society and Health. Linköping University, Faculty of Medicine and Health Sciences.
    Nordlund, Jessica
    Uppsala Univ, Sweden.
    Norén-Nyström, Ulrika
    Umeå Univ, Sweden.
    Palle, Josefine
    Uppsala Univ, Sweden.
    Thangavelu, Tharshini
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Society and Health. Linköping University, Faculty of Medicine and Health Sciences.
    Palmqvist, Lars
    Sahlgrens Univ Hosp, Sweden; Univ Gothenburg, Sweden.
    Wirta, Valtteri
    Karolinska Inst, Sweden.
    Cavelier, Lucia
    Uppsala Univ, Sweden.
    Fioretos, Thoas
    Div Lab Med, Sweden; Lund Univ, Sweden.
    Rosenquist, Richard
    Karolinska Inst, Sweden; Karolinska Univ Hosp, Sweden.
    A Study Protocol for Validation and Implementation of Whole-Genome and -Transcriptome Sequencing as a Comprehensive Precision Diagnostic Test in Acute Leukemias2022In: Frontiers in Medicine, E-ISSN 2296-858X, Vol. 9, article id 842507Article in journal (Refereed)
    Abstract [en]

    Background: Whole-genome sequencing (WGS) and whole-transcriptome sequencing (WTS), with the ability to provide comprehensive genomic information, have become the focal point of research interest as novel techniques that can support precision diagnostics in routine clinical care of patients with various cancer types, including hematological malignancies. This national multi-center study, led by Genomic Medicine Sweden, aims to evaluate whether combined application of WGS and WTS (WGTS) is technically feasible and can be implemented as an efficient diagnostic tool in patients with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). In addition to clinical impact assessment, a health-economic evaluation of such strategy will be performed.

    Methods and Analysis: The study comprises four phases (i.e., retrospective, prospective, real-time validation, and follow-up) including approximately 700 adult and pediatric Swedish AML and ALL patients. Results of WGS for tumor (90×) and normal/germline (30×) samples as well as WTS for tumors only will be compared to current standard of care diagnostics. Primary study endpoints are diagnostic efficiency and improved diagnostic yield. Secondary endpoints are technical and clinical feasibility for routine implementation, clinical utility, and health-economic impact.

    Discussion: Data from this national multi-center study will be used to evaluate clinical performance of the integrated WGTS diagnostic workflow compared with standard of care. The study will also elucidate clinical and health-economic impacts of a combined WGTS strategy when implemented in routine clinical care.

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  • 161.
    Appelgren, Leif
    Linköping University, Department of Management and Engineering. Linköping University, Faculty of Arts and Sciences.
    A survey of models for determining optimal audit strategies2020In: Advances in Accounting, ISSN 0882-6110, Vol. 48, article id 100455Article in journal (Refereed)
    Abstract [en]

    The problem studied in this survey is how to optimize the allocation of audit resources over an auditee population with respect to available population statistics. The auditees are assumed to optimize their expected utility based on information about the audit strategy. This survey is limited to models where the auditee can vary the fraud amount along a continuous scale. If the auditor is not able or willing to announce the audit strategy, a Nash equilibrium can be derived in which the auditor and auditee correctly anticipate each others strategies. If the auditor announces the audit strategy in advance, the problem is formulated as a sequential game with perfect information which is solved as an optimization problem. Early models in the literature resulted in unrealistically high degrees of fraud. Later models have incorporated a split into one group of inherently honest auditees and another group of potentially dishonest auditees. The fraction of inherently honest auditees is exogenous. In this paper, the four combinations of non-announcing/pre-announcing the strategy and all potentially dishonest/some inherently honest auditees are studied. For the case of pre-announcing the strategy with some inherently honest auditees, two new solution methods are presented. Two main conclusions are as follows. First, models with some inherently honest auditees have greater external validity. Second, when a pre-announced strategy is feasible, as it often is with tax and benefit audits, the pre-announced strategy is preferred by the auditor over the non-announced strategy. (C) 2020 The Author(s). Published by Elsevier Ltd.

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  • 162.
    Pavlidis, George
    et al.
    Linköping University, Department of Culture and Society, Division of Ageing and Social Change. Linköping University, Faculty of Arts and Sciences. South East European Res Ctr, Greece.
    Downs, Carolyn
    Univ Lancaster, England.
    Kalinowski, T. Bartosz
    Univ Lodz, Poland.
    Swiatek-Barylska, Ilona
    Univ Lodz, Poland.
    Lazuras, Lambros
    Sheffield Hallam Univ, England.
    Ypsilanti, Antonia
    Sheffield Hallam Univ, England.
    Tsatali, Marianna
    South East European Res Ctr, Greece.
    A survey on the training needs of caregivers in five European countries2020In: Journal of Nursing Management, ISSN 0966-0429, E-ISSN 1365-2834, Vol. 28, p. 385-398Article in journal (Refereed)
    Abstract [en]

    Aim This survey explored caregivers perceived training needs in 5 European countries (United Kingdom, Greece, Bulgaria, Poland and Italy). Background Training can enhance the professional capacity of caregivers; however, caregivers training needs within Europe have not been examined recently. Methods A survey conducted in 2015 captured data from 550 caregivers using a convenience sampling strategy, through a structured questionnaire and additional open-ended items and by conducting statistical and content analysis. Results The results indicated basic nursing skills and specialization, as well as training in psychology-related skills like time management, emotion regulation, communication and advanced health care systems as the emerging training needs. There were some country differences in specific training need areas. Conclusions It was concluded that training in basic nursing skills and specialization in nursing specific conditions, in advanced health care systems and in psychology-related skills could add to the professional capacity of European caregivers employed in health and social care. Implications for nursing management The findings inform about employed caregivers training needs in Europe, which may contribute in the provision of quality care and organisational efficiency in health and social care.

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  • 163.
    Liu, Qiang
    et al.
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    Lambrix, Patrick
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    A system for debugging missing is-a structure in networked ontologies2010In: Data Integration in the Life Sciences 7th International Conference, DILS 2010, Gothenburg, Sweden, August 25-27, 2010. Proceedings / [ed] Patrick Lambrix and Graham Kemp, Springer Berlin/Heidelberg, 2010, p. 50-57Conference paper (Refereed)
    Abstract [en]

    Ontologies are recognized as a key technology for semantics-based integration of the many available biomedical data sources. However, developing ontologies is not an easy task and the resulting ontologies may have defects affecting the results of ontology-based data integration and retrieval. In this paper we present a system for debugging ontologies regarding an important kind of modeling defects. Our system supports a domain expert to detect and repair missing is-a structure in ontologies in a semi-automatic way. The input for our system is a set of ontologies networked by correct mappings between their terms. Our tool uses the ontologies and mappings as domain knowledge to detect missing is-a relations in these ontologies. It also assists the user in repairing the ontologies by generating and recommending possible ways of repairing and executing the chosen repairing strategy. The detection and repairing phases can be interleaved. We present our approach, an implemented system as well as an experiment with two anatomy ontologies.

  • 164.
    Li, Ying
    et al.
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Computer and Information Science, Database and information techniques.
    Lambrix, Patrick
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology. Högskolan i Gävle.
    A System for Repairing EL Ontologies Using Weakening and Completing2023In: The Semantic Web: ESWC 2023 Satellite Events. ESWC 2023. / [ed] Catia Pesquita, Hala Skaf-Molli, Vasilis Efthymiou, Sabrina Kirrane, Axel Ngonga, Diego Collarana, Renato Cerqueira, Mehwish Alam, Cassia Trojahn, Sven Hertling, Cham, 2023, p. 101-105Conference paper (Refereed)
    Abstract [en]

    The quality of ontologies in terms of their correctness and completeness is crucial for developing high-quality ontology-based applications. Traditional debugging techniques repair ontologies by removing unwanted axioms, but may thereby remove consequences that are correct in the domain of the ontology. We propose an interactive approach to mitigate the negative effects of removing unwanted axioms for EL  ontologies by axiom weakening and completing. This is the first approach that allows for different ways to combine removing, weakening and completing. The choice of combination strategy influences the amount of work for a domain expert as well as the completeness of the repaired ontology. In this paper we describe a system based on a repairing approach that allows for different such combinations 

  • 165. Order onlineBuy this publication >>
    Blomqvist, Stefan
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    A System Perspective on Energy End-Use Measures in a District Heated Region: Renovation of Buildings and Hydronic Pavement Systems2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    A district heating and cooling (DHC) system can be a viable piece of the puzzle in the efforts of reducing the greenhouse gas (GHG) emissions. Especially if the DHC system include combined heat and power (CHP) plants which enable electricity production from renewable resources. This is set forth in national energy targets and sustainable development goals (SDGs), adopted by the United Nations in 2015. Moreover, improved energy efficiency and energy savings are important factors in fulfilling the national targets of decreased energy intensity as well as reducing the use of fossil fuels.

    The aim of this thesis is to analyze the impacts of two energy end-use measures in a DHC network and their consequences on the efforts towards sustainable development. The end-use measures studied are (1) renovation of a multifamily building stock and (2) the use of a hydronic pavement system (HPS) including analysis of different control strategies. The end-use measures are assessed in terms of energy use and efficiency, use of renewable and fossil resources, and local and global GHG emissions. Lastly, it is analyzed how the results relate to national energy targets and SDGs. By using simulation and optimization models, several scenarios of end-use measures are analyzed in the two studies. In the first study, six scenarios are analyzed, as the renovation packages include measures on the envelope, ventilation and conversion from district heating to ground source heat pump. In the second study three scenarios are analyzed, where the HPS are operated all-time at a temperature below 4°C or are shut down at temperatures below -10°C or at temperatures below -5°C.

    The results of the study regarding the renovation of a multifamily building stock indicate a future reduction in heat demand. All scenarios show energy savings of the studied building, which ranged from 11% to 56%. All scenarios show a reduction in local GHG emissions, as well as reduced fossil fuel use. Although the largest reduction was found in the use of renewable resources. From a global perspective on GHG emissions, the scenarios with district heating out-performed measures with heat pump solutions in the studied system. Moreover, the study point to positive impacts on the efforts towards SDGs.

    To mitigate the reduced heat demand from the renovation of the building stock, an HPS may be used. The results show mostly renewable resources were used for the HPS. The use of HPS was found to generate a positive impact on global GHG emissions. A control strategy that shuts down the HPS at temperatures below -10°C would result in 10% energy saving and would maintain acceptable performance of the HPS. Furthermore, it would reduce the use of fossil fuel and reduce local GHG emissions by 25%. Moreover, an HPS may contribute to SDGs.

    It is concluded that energy end-use measures of renovating a multifamily building stock are vital in the work towards an improved energy intensity. However, these measures result in a decreased demand for heat in the DHC network. This can then lead to reduced electricity production from renewable resources in the CHP plants, which in turn have a negative impact on the global GHG emissions. By finding new applications, like HPS, the infrastructure of DHC networks could be utilized efficiently and serve as one piece of the puzzle that is the efforts towards sustainable development.

    List of papers
    1. The Impact on System Performance When Renovating a Multifamily Building Stock in a District Heated Region
    Open this publication in new window or tab >>The Impact on System Performance When Renovating a Multifamily Building Stock in a District Heated Region
    Show others...
    2019 (English)In: Sustainability, E-ISSN 2071-1050, Vol. 11, no 8, article id 2199Article in journal (Other academic) Published
    Abstract [en]

    In Sweden, 90% of multifamily buildings utilize district heat and a large portion is in need of renovation. The aim is to analyze the impact of renovating a multifamily building stock in a district heating and cooling system, in terms of primary energy savings, peak power demands, electricity demand and production, and greenhouse gas emissions on local and global levels. The study analyzes scenarios regarding measures on the building envelope, ventilation, and substitution from district heat to ground source heat pump. The results indicate improved energy performance for all scenarios, ranging from 11% to 56%. Moreover, the scenarios present a reduction of fossil fuel use and reduced peak power demand in the district heating and cooling system ranging from 1 MW to 13 MW, corresponding to 4–48 W/m2 heated building area. However, the study concludes that scenarios including a ground source heat pump generate significantly higher global greenhouse gas emissions relative to scenarios including district heating. Furthermore, in a future fossil-free district heating and cooling system, a reduction in primary energy use will lead to a local reduction of emissions along with a positive effect on global greenhouse gas emissions, outperforming measures with a ground source heat pump.

    Place, publisher, year, edition, pages
    MDPI, 2019
    Keywords
    district heating, multifamily buildings, renovation, primary energy use, energy system modeling, greenhouse gas emissions
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-157080 (URN)10.3390/su11082199 (DOI)000467752200012 ()2-s2.0-85065422245 (Scopus ID)
    Available from: 2019-05-27 Created: 2019-05-27 Last updated: 2023-03-20Bibliographically approved
    2. Analyzing the Performance and Control of a Hydronic Pavement System in a District Heating Network
    Open this publication in new window or tab >>Analyzing the Performance and Control of a Hydronic Pavement System in a District Heating Network
    2019 (English)In: Energies, E-ISSN 1996-1073, Vol. 12, no 11, article id 2078Article in journal (Refereed) Published
    Abstract [en]

    A hydronic pavement system (HPS) is an alternative method to clear snow and ice, which avoids the use of salt, sand, and fossil fuel in conventional snow clearance, and minimizes the risk of accidents. The aim is to analyze the performance of different control strategies for a 35,000 m2 HPS utilizing heat from a district heating and cooling (DHC) system. The key performance indicators are (1) energy performance of the HPS, and (2) primary energy use, (3) electricity production and (4) greenhouse gas (GHG) emissions from the DHC system. The methodology uses a simulation model of the HPS and an optimization model of the DHC system. Three operational strategies are analyzed: A reference scenario based on the current control strategy, and scenarios where the HPS is shut down at temperatures below −10 °C and −5 °C. The study shows that the DHC return temperature is suitable for use. By operational strategies, use during peak demand in the DHC system can be avoided, resulting in reduced use of fossil fuel. Moreover, the energy use of the HPS could be reduced by 10% and the local GHG emissions by 25%. The study emphasizes that the HPS may have positive effects on global GHG emissions, as it enables electricity production from renewable resources.

    Place, publisher, year, edition, pages
    Basel: MDPI, 2019
    National Category
    Energy Systems Energy Engineering
    Identifiers
    urn:nbn:se:liu:diva-157189 (URN)10.3390/en12112078 (DOI)000472635900045 ()
    Note

    Funding agencies: Swedish Agency for Economic and Regional Growth; Tekniska verken AB; E. ON Sweden AB; Stangastaden AB; AB Lejonfastigheter; Fastighets AB L E Lundberg; Akademiska Hus AB

    Available from: 2019-06-04 Created: 2019-06-04 Last updated: 2023-08-28Bibliographically approved
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  • 166.
    Larsson, B.
    et al.
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Björk, J.
    Skåne University Hospital, Sweden .
    Börsbo, Björn
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    A systematic review of risk factors associated with transitioning from regional musculoskeletal pain to chronic widespread pain2012In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 16, no 8, p. 1084-1093Article, review/survey (Refereed)
    Abstract [en]

    Chronic widespread pain has limited treatment options and is associated with pronounced negative individual and socioeconomic consequences. Patients with local or regional pain may be at a risk for developing chronic widespread pain. Knowledge of such risk factors can help prevent chronic widespread pain. This study systematically reviews the literature that examines risk factors associated with developing chronic widespread after developing chronic regional pain. We conducted a three-step database search in Medline. Four articles from the authors files formed a core set of articles that were used to validate the search strategy. We conducted a systematic quality assessment of the included studies. Based on risk estimations reported in six prospective population-based studies and one retrospective study on pain, this study identified five risk factors: female sex, higher age, family history of pain, depressed mode and pain sites at baseline. As only a few studies were recovered, the impact of these factors is unclear. Spreading of pain from local or regional pain to widespread pain occurs in a large proportion of the general population. Few studies have addressed similar risk factors and the few risk factors associated with the transition from chronic regional pain to chronic widespread pain are inconsistent. Studies that focus on this transition have included few subjects and few possible risk factors. Future studies should explore more possible risk factors.

  • 167.
    Kirk, Jeanette Wassar
    et al.
    Univ Copenhagen, Denmark.
    Bodilsen, Ann Christine
    Univ Copenhagen, Denmark; Dept Exercise and Hlth, Denmark.
    Tjornhoj-Thomsen, Tine
    Univ Southern Denmark, Denmark.
    Pedersen, Mette Merete
    Phys Med and Rehabil Res Copenhagen PMR C, Denmark; Univ Copenhagen, Denmark.
    Bandholm, Thomas
    Phys Med and Rehabil Res Copenhagen PMR C, Denmark; Univ Copenhagen, Denmark.
    Husted, Rasmus Kov
    Phys Med and Rehabil Res Copenhagen PMR C, Denmark; Univ Copenhagen, Denmark.
    Poulsen, Lise Kronborg
    Univ Copenhagen, Denmark.
    Petersen, Janne
    Univ Copenhagen, Denmark; Univ Copenhagen, Denmark.
    Andersen, Ove
    Univ Copenhagen, Denmark.
    Nilsen, Per
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    A tailored strategy for designing the Walk-Copenhagen (WALK-Cph) intervention to increase mobility in hospitalised older medical patients: a protocol for the qualitative part of the WALK-Cph project2018In: BMJ Open, E-ISSN 2044-6055, Vol. 8, no 3, article id e020272Article in journal (Refereed)
    Abstract [en]

    Introduction Older medical patients (amp;gt;65 years) represent 54% of the admissions to Danish medical and emergency departments. Acute admissions and bed rest during hospitalisation are independent risk factors for death and dependency in older patients. Even short hospitalisations are associated with increased dependency in activities of daily living after discharge. Interventions that increase mobility during hospitalisation are therefore important. The purpose of this protocol is to describe the intervention design of the WALK =-Copenhagen project, aimed at increasing 24 hours mobility in older medical patients during acute hospitalisations and following discharge. Methods and analysis This study is based on ethnographic fieldwork and interviews. Workshops are used to develop and co-design the intervention in collaboration with key stakeholders (patients, relatives, health professionals and researchers). The theory of cultural learning processes, and fire cultural historical activity theory will be used to help us understand the interaction between health professionals, structures arid objects in relation to mobility in the medical departments. Ethics and dissemination The project will adhere to the directives of the Helsinki Declaration. Ethical approval was not required for the study since formal ethical approval is not mandatory for studies that do not involve biomedical issues (I-Suite no: 05078) according to Danish law. Informed consent was obtained for all participants. The results will be disseminated to health professionals, managers, patients arid relatives, who will be invited to afternoon meetings where the project will be discussed. The results will be published in peer-reviewed scientific journals and presented at scientific conferences.

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  • 168.
    Hu, Zhang-Jun
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Hu, Jiwen
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Tongji University, Peoples R China.
    Wang, Hui
    Anhui University, Peoples R China.
    Zhang, Qiong
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Zhao, Meng
    Anhui University, Peoples R China.
    Brommesson, Caroline
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Tian, Yupeng
    Anhui University, Peoples R China.
    Gao, Hongwen
    Tongji University, Peoples R China.
    Zhang, Xuanjun
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. University of Macau, Peoples R China.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    A TPA-caged precursor of (imino)coumarin for "turn-on" fluorogenic detection of Cu+2016In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 933, p. 189-195Article in journal (Refereed)
    Abstract [en]

    We strategize to utilize the precursors of (imino) coumarin fluorophores to deliver novel reactive Cu+ probes, where tris[(2-pyridyl)-methyl] amine (TPA) works as a reactive receptor towards Cu+. To verify this strategy, CP1, a representative probe and relevant sensing behaviors towards Cu+ are presented here. CP1 features good solubility and fast response for monitoring labile copper in aqueous solution and live cells. The sensing mechanism of CP1 is determined by HPLC titration and mass spectrometric analysis. The probe CP1 exhibits a 60-fold fluorescence enhancement and a detection limitation of 10.8 nM upon the detection of Cu+. CP1 is further applied for imaging labile copper in live cells. This work provides a starting point for future development of Cu+ probes, based on in situ formation of (imino) coumarin scaffolds, as well as their further investigations of copper signaling and biological events. (C) 2016 Elsevier B.V. All rights reserved.

  • 169. Order onlineBuy this publication >>
    Semnani Kenlind, Sarah
    Linköping University, Department of Management and Engineering, Industrial Economics. Linköping University, Faculty of Science & Engineering.
    A Typology of Business Model Changes: Cases from Swedish Wood Manufacturing Industry2020Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis aims to contribute to a better understanding of the business model (BM) change concept. The study purpose is achieved through developing a context-specific method and framework to measure and characterize different types of BM changes. This work promotes the importance of context-specific studies in the field of BM. It is pointed out that mature industries with slower rates of change or less complex technologies have not received enough attention in this field. Companies within these industries play a dominant role in the economic prosperity of nations and undergo different types of change. Therefore, the low-tech nature of these changes does not imply a lack of significance or complexity.

    The Swedish wood manufacturing industry is chosen to represent mature low-tech industries as the context of this study. This industry is currently undergoing a series of changes, brought about by both internal and external forces. Five companies active in this industry are purposefully sampled as case studies. Despite being part of the same industry, the selected case companies each undergo a varying degree or type of change.

    The study proposes a firm-level BM framework, which is suitable for studying organizational changes in this context. The proposed BM framework comprises three main dimensions of Operational platform, Offerings and Market, as well as three BM components under each dimension. The changes in the BMs of case companies are studied by depicting and comparing their BMs at three points in time over a ten-year period. BM changes are measured from the two dimensions of degree and scope of change in this thesis.

    Measuring the BM changes from the two dimensions of degree and scope of change provides valuable insight about different types of changes in the industry. First, it depicts how big a change took place in the different BM components of the case companies. Second, it demonstrates the size of the ‘chain effects’ each change caused within each BM dimension and the entire BM. These findings assist in proposing a typology of BM changes (BMCs). BMCs can be categorized as four different types – incremental, modular, architectural and transformational – depending on the possible combinations in the varying degree and scope of change.

    This thesis confirms the claims made by previous scholars that contingency factors can limit the range of feasible change strategies for companies. The results show that the majority of BM changes in this industry have been architectural BMCs. These involve fine-tuning most of the BM components, with the aim of resuming the fit between BM dimensions and BM components in companies’ BMs. Furthermore, due to the context-specific contingency factors, creating a parallel BM appears to be a more plausible option than completely transforming BMs in these industries. Lastly, this work highlights the importance of a balance and interplay between strategy, external industry-related and internal resource-based factors in companies’ BMCs.

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  • 170.
    Gustafsson, Mika
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Gawel, Danuta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Alfredsson, Lars
    Karolinska Institute, Sweden.
    Baranzini, Sergio
    University of Calif San Francisco, CA, USA.
    Bjorkander, Janne
    County Council Jonköping, Sweden.
    Blomgran, Robert
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Hellberg, Sandra
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Eklund, Daniel
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Ernerudh, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Kockum, Ingrid
    Karolinska Institute, Sweden; Centre Molecular Med, Sweden.
    Konstantinell, Aelita
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Arctic University of Norway, Norway.
    Lahesmaa, Riita
    University of Turku, Finland; Abo Akad University, Finland.
    Lentini, Antonio
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Liljenström, H. Robert I.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Mattson, Lina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Matussek, Andreas
    County Council Jonköping, Sweden.
    Mellergård, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Neurology.
    Mendez, Melissa
    University of Peruana Cayetano Heredia, Peru.
    Olsson, Tomas
    Karolinska Institute, Sweden; Centre Molecular Med, Sweden.
    Pujana, Miguel A.
    Catalan Institute Oncol, Spain.
    Rasool, Omid
    University of Turku, Finland; Abo Akad University, Finland.
    Serra-Musach, Jordi
    Catalan Institute Oncol, Spain.
    Stenmarker, Margaretha
    County Council Jonköping, Sweden.
    Tripathi, Subhash
    University of Turku, Finland; Abo Akad University, Finland.
    Viitala, Miro
    University of Turku, Finland; Abo Akad University, Finland.
    Wang, Hui
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. University of Texas MD Anderson Cancer Centre, TX 77030 USA.
    Zhang, Huan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Nestor, Colm
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Benson, Mikael
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Allergy Center.
    A validated gene regulatory network and GWAS identifies early regulators of T cell-associated diseases2015In: Science Translational Medicine, ISSN 1946-6234, E-ISSN 1946-6242, Vol. 7, no 313, article id 313ra178Article in journal (Refereed)
    Abstract [en]

    Early regulators of disease may increase understanding of disease mechanisms and serve as markers for presymptomatic diagnosis and treatment. However, early regulators are difficult to identify because patients generally present after they are symptomatic. We hypothesized that early regulators of T cell-associated diseases could be found by identifying upstream transcription factors (TFs) in T cell differentiation and by prioritizing hub TFs that were enriched for disease-associated polymorphisms. A gene regulatory network (GRN) was constructed by time series profiling of the transcriptomes and methylomes of human CD4(+) T cells during in vitro differentiation into four helper T cell lineages, in combination with sequence-based TF binding predictions. The TFs GATA3, MAF, and MYB were identified as early regulators and validated by ChIP-seq (chromatin immunoprecipitation sequencing) and small interfering RNA knockdowns. Differential mRNA expression of the TFs and their targets in T cell-associated diseases supports their clinical relevance. To directly test if the TFs were altered early in disease, T cells from patients with two T cell-mediated diseases, multiple sclerosis and seasonal allergic rhinitis, were analyzed. Strikingly, the TFs were differentially expressed during asymptomatic stages of both diseases, whereas their targets showed altered expression during symptomatic stages. This analytical strategy to identify early regulators of disease by combining GRNs with genome-wide association studies may be generally applicable for functional and clinical studies of early disease development.

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  • 171.
    Badam, Tejaswi
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering. Univ Skovde, Sweden.
    de Weerd, Hendrik Arnold
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering. Univ Skovde, Sweden.
    Martinez, David
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Olsson, Tomas
    Karolinska Inst, Sweden.
    Alfredsson, Lars
    Karolinska Inst, Sweden; Karolinska Inst, Sweden.
    Kockum, Ingrid
    Karolinska Inst, Sweden.
    Jagodic, Maja
    Karolinska Inst, Sweden.
    Lubovac-Pilav, Zelmina
    Univ Skovde, Sweden.
    Gustafsson, Mika
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    A validated generally applicable approach using the systematic assessment of disease modules by GWAS reveals a multi-omic module strongly associated with risk factors in multiple sclerosis2021In: BMC Genomics, E-ISSN 1471-2164, Vol. 22, no 1, article id 631Article in journal (Refereed)
    Abstract [en]

    Background There exist few, if any, practical guidelines for predictive and falsifiable multi-omic data integration that systematically integrate existing knowledge. Disease modules are popular concepts for interpreting genome-wide studies in medicine but have so far not been systematically evaluated and may lead to corroborating multi-omic modules. Result We assessed eight module identification methods in 57 previously published expression and methylation studies of 19 diseases using GWAS enrichment analysis. Next, we applied the same strategy for multi-omic integration of 20 datasets of multiple sclerosis (MS), and further validated the resulting module using both GWAS and risk-factor-associated genes from several independent cohorts. Our benchmark of modules showed that in immune-associated diseases modules inferred from clique-based methods were the most enriched for GWAS genes. The multi-omic case study using MS data revealed the robust identification of a module of 220 genes. Strikingly, most genes of the module were differentially methylated upon the action of one or several environmental risk factors in MS (n = 217, P = 10(- 47)) and were also independently validated for association with five different risk factors of MS, which further stressed the high genetic and epigenetic relevance of the module for MS. Conclusions We believe our analysis provides a workflow for selecting modules and our benchmark study may help further improvement of disease module methods. Moreover, we also stress that our methodology is generally applicable for combining and assessing the performance of multi-omic approaches for complex diseases.

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  • 172.
    Gawel, Danuta
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Serra-Musach, Jordi
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Lilja, Sandra
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Aagesen, Jesper
    Reg Jonkoping Cty, Sweden.
    Arenas, Alex
    Univ Rovira and Virgili, Spain.
    Asking, Bengt
    Reg Jonkoping Cty, Sweden.
    Bengner, Malin
    Reg Jonkoping Cty, Sweden.
    Bjorkander, Janne
    Reg Jonkoping Cty, Sweden.
    Biggs, Sophie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Ernerudh, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Hjortswang, Henrik
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Gastroentorology. Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science.
    Karlsson, Jan-Erik
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Reg Jonkoping Cty, Sweden.
    Köpsén, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Jung Lee, Eun Jung
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences. Yonsei Univ, South Korea.
    Lentini, Antonio
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Li, Xinxiu
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Magnusson, Mattias
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Martinez, David
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Matussek, Andreas
    Reg Jonkoping Cty, Sweden; Karolinska Inst, Sweden; Karolinska Univ Hosp, Sweden.
    Nestor, Colm
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Schäfer, Samuel
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health.
    Seifert, Oliver
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences. Reg Jonkoping Cty, Sweden.
    Sonmez, Ceylan
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Stjernman, Henrik
    Reg Jonkoping Cty, Sweden.
    Tjärnberg, Andreas
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Wu, Simon
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Åkesson, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences. Reg Jonkoping Cty, Sweden.
    Shalek, Alex K.
    MIT, MA 02139 USA; Broad Inst MIT and Harvard, MA 02142 USA; Ragon Inst MGH MIT and Harvard, MA USA.
    Stenmarker, Margaretha
    Reg Jonkoping Cty, Sweden; Inst Clin Sci, Sweden.
    Zhang, Huan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Gustafsson, Mika
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Benson, Mikael
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, H.K.H. Kronprinsessan Victorias barn- och ungdomssjukhus Linköping/Motala.
    A validated single-cell-based strategy to identify diagnostic and therapeutic targets in complex diseases2019In: Genome Medicine, ISSN 1756-994X, E-ISSN 1756-994X, Vol. 11, article id 47Article in journal (Refereed)
    Abstract [en]

    Background

    Genomic medicine has paved the way for identifying biomarkers and therapeutically actionable targets for complex diseases, but is complicated by the involvement of thousands of variably expressed genes across multiple cell types. Single-cell RNA-sequencing study (scRNA-seq) allows the characterization of such complex changes in whole organs.

    Methods

    The study is based on applying network tools to organize and analyze scRNA-seq data from a mouse model of arthritis and human rheumatoid arthritis, in order to find diagnostic biomarkers and therapeutic targets. Diagnostic validation studies were performed using expression profiling data and potential protein biomarkers from prospective clinical studies of 13 diseases. A candidate drug was examined by a treatment study of a mouse model of arthritis, using phenotypic, immunohistochemical, and cellular analyses as read-outs.

    Results

    We performed the first systematic analysis of pathways, potential biomarkers, and drug targets in scRNA-seq data from a complex disease, starting with inflamed joints and lymph nodes from a mouse model of arthritis. We found the involvement of hundreds of pathways, biomarkers, and drug targets that differed greatly between cell types. Analyses of scRNA-seq and GWAS data from human rheumatoid arthritis (RA) supported a similar dispersion of pathogenic mechanisms in different cell types. Thus, systems-level approaches to prioritize biomarkers and drugs are needed. Here, we present a prioritization strategy that is based on constructing network models of disease-associated cell types and interactions using scRNA-seq data from our mouse model of arthritis, as well as human RA, which we term multicellular disease models (MCDMs). We find that the network centrality of MCDM cell types correlates with the enrichment of genes harboring genetic variants associated with RA and thus could potentially be used to prioritize cell types and genes for diagnostics and therapeutics. We validated this hypothesis in a large-scale study of patients with 13 different autoimmune, allergic, infectious, malignant, endocrine, metabolic, and cardiovascular diseases, as well as a therapeutic study of the mouse arthritis model.

    Conclusions

    Overall, our results support that our strategy has the potential to help prioritize diagnostic and therapeutic targets in human disease.

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  • 173. Order onlineBuy this publication >>
    Janbakhsh, Setareh
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    A Ventilation Strategy Based on Confluent Jets: An Experimental and Numerical Study2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This study presents air distribution systems that are based on confluent jets; this system can be of interest for the establishment of indoor environments, to fulfill the goals of indoor climate and energy-efficient usage. The main objective of this study is to provide deeper understanding of the flow field development of a supply device that is designed based on wall confluent jets and to investigate the ventilation performance by experimental and numerical methods. In this study, the supply device can be described as an array of round jets on a flat surface attached to a side wall. Multiple round jets that issue from supply device apertures are combined at a certain distance downstream from the device and behave as a united jet or so-called confluent jets. Multiple round jets that are generated from the supply device move downward and are attached to the wall at the primary region, due to the Coanda effect, and then they become wall confluent jets until the floor wall is reached. A wall jet in a secondary region is formed along the floor after the stagnation region.

    The characteristics of the flow field and the ventilation performance of conventional wall confluent jets and modified wall confluent jets supply devices are investigated experimentally in an office test room. The study of the modified wall confluent jets is intended to improve the efficiency of the conventional one while maintaining acceptable thermal comfort in an office environment. The results show that the modified wall confluent jets supply device can provide acceptable thermal comfort for the occupant with lower airflow rate compared to the conventional wall confluent jets supply device.

    Numerical predictions using three turbulence models (renormalization group (RNG k– ε), realizable (Re k– ε), and shear stress transport (SST k– ω) are evaluated by measurement results. The computational box and nozzle plate models are used to model the inlet boundary conditions of the nozzle device. In the isothermal study, the wall confluent jets in the primary region and the wall jet in the secondary region, when predicted by the three turbulence models, are in good agreement with the measurements. The non-isothermal validation studies show that the SST k– ω model is slightly better at predicting the wall confluent jets than the other two models. The SST k– ω model is used to investigate the effects of the nozzle diameter, number of nozzles, nozzle array configuration, and inlet discharge height on the ventilation performance of the proposed wall confluent jets supply device. The nozzle diameter and number of nozzles play important roles in determining the airflow pattern, temperature field, and draught distribution. Increased temperature stratification and less draught distribution are achieved by increasing the nozzle diameter and number of nozzles. The supply device with smaller nozzle diameters and fewer nozzles yields rather uniform temperature distribution due to the dominant effect of mixing. The flow behavior is nearly independent of the inlet discharge height for the studied range.

    The proposed wall confluent jets supply device is compared with a mixing supply device, impinging supply device and displacement supply device. The results show that the proposed wall confluent jets supply device has the combined behavior of both mixing and stratification principles. The proposed wall confluent jets supply device provides better overall ventilation performance than the mixing and displacement supply devices used in this study.

    This study covers also another application of confluent jets that is based on impinging technology. The supply device under consideration has an array of round jets on a curve. Multiple jets issue from the supply device aperture, in which the supply device is positioned vertically and the jets are directed against a target wall. The flow behavior and ventilation performance of the impinging confluent jets supply device is studied experimentally in an industrial premise. The results show that the impinging confluent jets supply device maintains acceptable thermal comfort in the occupied zone by creating well-distributed airflow during cold and hot seasons.

    List of papers
    1. Experimental investigation of a new supply diffuser in an office room
    Open this publication in new window or tab >>Experimental investigation of a new supply diffuser in an office room
    2009 (English)In: Proceedings of 11th International Conference on Air Distribution in Rooms. ROOMVENT, 2009,Busan, Korea, 2009Conference paper, Published paper (Other academic)
    Abstract [en]

    Full-scale measurements were carried out for investigation of thermal comfort in an office room for a new supply air diffuser. Results of the measurements were performed with both wholefield measuring and traditional point measuring techniques. Experimental results were carried out for supply Archimedes numbers varying from 0.03 to 0.16 and two cooling loads, i.e. 55 and 70 W/m2. Characteristics of indoor environment and occupants’ comfort were explored and analyzed. It was concluded that the airflow pattern and thermal comfort from the investigated low-velocity diffuser were in good agreement with standard ISO 7730.

    National Category
    Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-117438 (URN)
    Conference
    The 11th International Conference on Air Distribution in Rooms. ROOMVENT, May 24-27, Busan, Korea
    Available from: 2015-04-27 Created: 2015-04-27 Last updated: 2015-05-04Bibliographically approved
    2. Experimental investigation of a ventilation system based on wall confluent jets
    Open this publication in new window or tab >>Experimental investigation of a ventilation system based on wall confluent jets
    2014 (English)In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 80, p. 18-31Article in journal (Refereed) Published
    Abstract [en]

    The flow behavior of isothermal and non-isothermal wall confluent jets (WCJ) ventilation system was investigated experimentally in a mock-up office environment. Two flow regions were identified: first, a primary region is developed below the supply device, with axis along the inlet wall, and a secondary wall-jet forms along the floor. The velocity and temperature fields were recorded by traversing a hot wire and thermistor anemometers for both primary and secondary regions. The results show self-similarity characteristic of the velocity and temperature profiles for both isothermal and non-isothermal WCJ. Maximum velocity decay and its spreading rate are linear and independent of the inlet airflow rate. Minimum temperature difference and its spread also show linear decay. The spreading rates for maximum velocity are similar in both the primary and secondary regions normal to the inlet wall and floor, respectively, which is consistent with previous studies on wall jets. The variation of draught rating is evaluated via mean velocity, turbulence intensity and temperature. Although the WCJ has slow velocity decay, which enables it to cover almost the entire floor of the test room, the draught is acceptable in the occupied zone according to ISO 7730. PMV (predicted mean vote) and PPD (predicted percentage dissatisfied) are presented for the occupied zone of the room.

    Place, publisher, year, edition, pages
    Elsevier, 2014
    Keywords
    Ventilation system; Supply device; Wall confluent jets; Measurement; Draught rate; Thermal comfort indices
    National Category
    Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-110263 (URN)10.1016/j.buildenv.2014.05.011 (DOI)000340323300003 ()
    Note

    Funding Agencies|University of Gavle, Sweden; Stravent AB, Finland

    Available from: 2014-09-05 Created: 2014-09-05 Last updated: 2017-12-05
    3. Numerical study of a ventilation system based on wall confluent jets
    Open this publication in new window or tab >>Numerical study of a ventilation system based on wall confluent jets
    2014 (English)In: HVAC & R RESEARCH, ISSN 1078-9669, E-ISSN 1938-5587, Vol. 20, no 8, p. 846-861Article in journal (Refereed) Published
    Abstract [en]

    This study presents numerical investigation of an air supply device based on wall confluent jets in a ventilated room. Confluent jets can be described as multiple round jets issuing from supply device apertures. The jets converge, merge, and combine at a certain distance downstream from the supply device and behave as a united jet, or so-called confluent jet. The numerical predictions of the velocity flow field of isothermal confluent jets with three Reynolds-averaged Navier-Stokes turbulence models (renormalization group k-epsilon, realizable k-epsilon, and shear stress transport k-omega) are reported in the present study. The results of the numerical predictions are verified with detailed experimental measurements by a hot wire anemometer and constant temperature anemometers for two airflow rates. The box method is used to provide the inlet boundary conditions. The study of the airflow distribution shows that a primary wall jet (wall confluent jet) exists close to the supply device along the wetted wall, and a secondary wall jet is created after the stagnation region along the floor. It is presented that the flow field of the primary and secondary wall jet predicted by turbulence models is in good agreement with the experimental data. The current study is also compared with the literature in terms of velocity decay and the spreading rate of the primary and secondary wall jet, the results of which are consistent with each other. Velocity decay and the spreading rate of the secondary wall jet in vertical and lateral directions were studied for different inlet airflow rates and inlet discharge heights. The comparative results demonstrate that the flow behavior is nearly independent of the inlet flow rate. Inlet discharge height is found to have impact close to the inlet, where the velocity decays faster when the jet discharges at higher level. The decay tendency is similar as the jet enters into the room for all discharge heights.

    Place, publisher, year, edition, pages
    Taylor and Francis: STM, Behavioural Science and Public Health Titles - No Open Select, 2014
    National Category
    Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-112461 (URN)10.1080/10789669.2014.957111 (DOI)000344407100002 ()
    Note

    Funding Agencies|University of Gavle; Stravent AB, Finland

    Available from: 2014-11-28 Created: 2014-11-28 Last updated: 2017-12-05
    4. Investigation of design parameters for an air supply device based on wall confluent jets
    Open this publication in new window or tab >>Investigation of design parameters for an air supply device based on wall confluent jets
    2015 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Numerical predictions of the flow field generated by an air supply device based on wall confluent jets are investigated. The numerical predictions of three turbulence models (RNG 𝑘 − 𝜀, Re 𝑘 − 𝜀, and SST 𝑘 − 𝜔) are compared by velocity and temperature measurements. Ventilation performance in terms of thermal comfort and ventilation efficiency is numerically investigated by systematically varying the design of the air supply (nozzle array configuration, nozzle diameter, number of nozzles, and inlet discharge height). The numerical predictions accomplished by the SST 𝑘 − 𝜔 model provide the best agreement with the experimental results. The numerical predictions for supply devices of varying design configuration show that different device designs provide acceptable thermal environments and efficient heat removal. The nozzle diameter and number of nozzles play important roles in determining the airflow pattern, temperature field, and draught distribution. Increased temperature stratification and less draught distribution are achieved by increasing the nozzle diameter and number of nozzles. The spreading rates of the wall jet along the vertical direction for the cases studied are in close agreement with each other and independent of the studied parameters. The flow behavior is rarely independent of the inlet discharge height and configuration of the nozzle array for the studied range.

    Keywords
    Wall confluent jets supply device, Numerical predictions, Parametric studies, Ventilation performance, Ventilation efficiency, Thermal comfort
    National Category
    Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-117437 (URN)
    Available from: 2015-04-27 Created: 2015-04-27 Last updated: 2015-04-27Bibliographically approved
    5. Numerical investigation of ventilation performance of different air supply devices in an office environment
    Open this publication in new window or tab >>Numerical investigation of ventilation performance of different air supply devices in an office environment
    2015 (English)In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 90, p. 37-50Article in journal (Refereed) Published
    Abstract [en]

    Abstract The aim of this study was to compare ventilation performance of four different air supply devices in an office environment with respect to thermal comfort, ventilation efficiency and energy-saving potential, by performing numerical simulations. The devices have the acronyms: Mixing supply device (MSD), Wall confluent jets supply device (WCJSD), Impinging jet supply device (IJSD) and Displacement supply device (DSD). Comparisons were made under identical set-up conditions, as well as at the same occupied zone temperature of about 24.2 °C achieved by adding different heat loads and using different air-flow rates. Energy-saving potential was addressed based on the air-flow rate and the related fan power required for obtaining a similar occupied zone temperature for each device. Results showed that the WCJSD and IJSD could provide an acceptable thermal environment while removing excess heat more efficiently than the MSD, as it combined the positive effects of both mixing and stratification principles. This benefit also meant that this devices required less fan power than the MSD for obtaining equivalent occupant zone temperature. The DSD showed a superior performance on heat removal, air exchange efficiency and energy saving to all other devices, but it had difficulties in providing acceptable vertical temperature gradient between the ankle and neck levels for a standing person.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keywords
    Ventilation performance, Air supply devices, Thermal comfort, Energy-saving potential
    National Category
    Energy Engineering
    Identifiers
    urn:nbn:se:liu:diva-117439 (URN)10.1016/j.buildenv.2015.03.021 (DOI)000356189000004 ()
    Note

    Formas [242-2008-835]; KK Foundation [2007/0289]; University of Gavle (Gavle, Sweden); Linkoping University (Linkoping, Sweden)

    Available from: 2015-04-27 Created: 2015-04-27 Last updated: 2018-07-26Bibliographically approved
    6. A Newly Designed Supply Diffuser for Industrial Premises
    Open this publication in new window or tab >>A Newly Designed Supply Diffuser for Industrial Premises
    2010 (English)In: The International Journal of Ventilation, ISSN 1473-3315, E-ISSN 2044-4044, Vol. 9, no 1, p. 59-67Article in journal (Refereed) Published
    Abstract [en]

    The results of this investigation revealed the airflow distribution from a new design of supply diffuser under non-isothermal conditions. To illustrate the indoor climate parameters in the occupied zone, for both the heating and cooling seasons, an experimental investigation was carried out in industrial premises. The indoor climate was explored at ankle, waist and neck levels for a standing person at different positions, to determine the variation of the thermal comfort indexes and draught rating (DR) with position in the facility. The observed PPD and DR values indicate acceptable levels of thermal comfort in the facility for both summer and winter cases. The conclusion can be drawn that well-distributed airflow saves energy by removing the need for an additional heating and cooling systems during cold and hot weather seasons.

    Place, publisher, year, edition, pages
    Veetech Ltd., 2010
    Keywords
    industrial ventilation; experimental investigation; indoor climate; supply diffuser
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-58296 (URN)000279036000006 ()
    Conference
    9th International Conference on Industrial Ventilation, Zurich, Switzerland, 18-21 October 2009
    Available from: 2010-08-10 Created: 2010-08-09 Last updated: 2017-12-12Bibliographically approved
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  • 174.
    Biricik, Alp
    Linköping University, The Tema Institute, The Department of Gender Studies. Linköping University, Faculty of Arts and Sciences.
    A Walk on Istiklal Street: Dissident Sexual Geographies, Politics and Citizenship in Istanbul2014Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Building upon ethnographic material and literature dating from the early 1970s until the 2010s, this thesis is about the production and transformation of dissident sexual geographies through the interplay of sexual politics and citizenship in Beyoğlu and Aksaray, two districts of Istanbul, Turkey. In particular, the interdisciplinary inquiry is composed in the form of a walk on Istiklal Street in Beyoğlu district, historically a central location for cruising activities, finding sexual communities and organising political events among LGBT circles. Throughout, the study focuses on the generational use of three interconnected areas: places, such as gay and transgender bars and clubs (1970s–2010s); politics, such as gay, lesbian, bisexual and transgender (LGBT) sexual identity politics (1980s–2010s), and virtualities, such as cyberspaces produced through internet and webcam technologies (1990s–2010s).

    As such, this study contributes to the literature in an under-researched area: the academic study of the production and transformation of dissident sexual geographies between the early 1970s and the early 2010s in Istanbul. Furthermore, it advances current debates on contemporary LGBT identity politics in relation to place-making processes and their role in subverting the assumptions of heteronormativity in the Turkish context. Lastly, the empirical material on three interwoven areas (places, politics and virtualities) contributes to theoretical debates on the construction of intimacy and privacy in the Turkish context.

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    omslag
  • 175.
    Panieri, Carlo
    et al.
    Linköping University, Department of Management and Engineering.
    Grüner, Kai
    Linköping University, Department of Management and Engineering.
    A way forward - Overcoming the challenges of contemporary Design Thinking research2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This paper aims to investigate the polarization present within the Design Thinking field ofresearch. Starting off from Johansson-Sköldberg et al. (2013), who first identified the distinctionbetween the two discourses Designerly Thinking and Design Thinking in 2010, we constructed a literature review and a framework of analysis based on conception of knowledge and its relationto the advancement of a research field. We claim that root-causes of the polarization derive from different knowledge bases, which then inhibit knowledge exchange as well as production. We conclude the paper by providing a suggestion for a way forward, claiming the applicability ofEngaged Scholarship within the realm of Design Thinking to make the field of research progresscreating relevance for both practitioners and scholars.

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  • 176.
    Eriksson, Jonas
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Data Transmission.
    A weight-based characterization of the set of correctable error patterns under list-of-2 decoding2007In: ADVANCES IN MATHEMATICS OF COMMUNICATIONS, ISSN 1930-5346, Vol. 1, no 3, p. 331-356Article in journal (Refereed)
    Abstract [en]

    List decoding of block codes is an alternative approach to the decoding problem with appealing qualities. The fairly recent development of efficient algorithms for list decoding of Reed-Solomon codes spur new fuel to the study of this decoding strategy. In this paper we give a weight-based characterization of the set of correctable error patterns under list-of-2 decoding of (tau, 2)-list-decodable linear codes with known weight distribution. We apply our characterization of the set of correctable error patterns to a few codes in a family of low-rate list-of-2 decodable Reed-Solomon codes. We study the increase in error-correction performance obtained in a symmetric AWGN channel by using list-of-2 decoding instead of traditional decoding for these codes. Some simulation results for list-of-2 decoding on QAM channels using the Guruswami-Sudan algorithm for decoding of Reed-Solomon codes are also presented.

  • 177.
    Eriksson, Jonas
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    A Weight-Based Characterization of the Set of Correctable Error patterns Under List-of-2 Decoding2007Report (Other academic)
    Abstract [en]

    List decoding of block codes is an alternative approach to the decoding problem with appealing qualities. The fairly recent development of efficient algorithms for list decoding of Reed-Solomon codes spur new fuel to the study of this decoding strategy. In this paper we give a weight-based characterization of the set of correctable error patterns under list-of-2 decoding of (tau, 2)-list-decodable linear codes with known weight distribution. We apply our characterization of the set of correctable error patterns to a few codes in a family of low-rate list-of-2 decodable Reed-Solomon codes. We study the increase in error-correction performance obtained in a symmetric AWGN channel by using list-of-2 decoding instead of traditional decoding for these codes. Some simulation results for list-of-2 decoding on QAM channels using the Guruswami-Sudan algorithm for decoding of Reed-Solomon codes are also presented.

  • 178.
    Lundqvist, Carolina
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Gregson, Warren
    Football Exchange, Research Institute of Sport Sciences, Liverpool John Mores University, Liverpool UK.
    Bonanno, Daniele
    Football Performance & Science Department, Aspire Academy, Doha.
    Lolli, Lorenzo
    Football Exchange, Research Institute of Sport Science, Liverpool John Mores University, Liverpool, UK.
    Di Salvo, Valter
    Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy.
    A worldwide survey of perspectives on demands, resources, and barriers influencing the youth-to-senior transition in academy football players2022In: International journal of sports science & coaching, ISSN 1747-9541, E-ISSN 2048-397XArticle in journal (Refereed)
    Abstract [en]

    The youth-to-first team phase presents a number of challenges in the careers of modern football players with stagnation, inconsistent performance and dropout being reported. The aim of this study was to investigate the perception of staff involved in professional academy football clubs around the globe, with a particular focus on youth and first team transition demands, resources as well as transitions barriers and coping among male academy football players. Participants from 29 male youth academies distributed across 29 countries took part in the survey. Our main findings suggested training and match intensity reported as being greater at the senior-level and also pressure from parents. The majority of respondents indicated their clubs having long-term strategy for player development and specific roles supporting successful player transitions. Exposure to different playing styles was deemed important to prepare players for the first team. Likewise, having the academy and the first team training on the same site was perceived to ease the transition, with the majority of respondents indicating that players are able to cope with the pressure of first team training and games. Perceptions on whether staff do not have the skills/resources to prepare players for the changes in environment and culture when players move from youth-to-senior level were unclear. Collectively, our study extends previous transition research on youth football academies suggesting the importance of a club-based playing philosophy to prepare players for the first team demands and challenges.

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  • 179.
    Andersson, Ola
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Electronics System.
    Vesterbacka, Mark
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Electronics System.
    A yield-enhancement strategy for binary-weighted DACs2005In: Proc. European Conf. Circuit Theory and Design 2005, ECCTD'05, 2005, , p. 55-58p. 55-58Conference paper (Refereed)
    Abstract [en]

    One of the major contributors to the static nonlinearity of a current-steering digital-to-analog converter (DAC) is mismatch between current sources. A technique for enhancing the yield of binary-weighted current-steering DACs is proposed. The technique utilizes a special case of a general technique for spectral shaping of DAC nonlinearity errors presented earlier and requires oversampling. The technique relies on two DAC models with low computational complexity that can be integrated with the DAC at a negligible cost in terms of area and power consumption. Behavioral-level simulation results indicate that the proposed method has a good potential of enhancing the yield of binary-weighted DACs for situations where the matching errors constitute the dominating source of nonlinearity.

  • 180.
    Skripnyak, Natalia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Ponomareva, A. V.
    Natl Univ Sci and Technol MISIS, Russia.
    Belov, M. P.
    Natl Univ Sci and Technol MISIS, Russia.
    Abrikosov, Igor A.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Ab initio calculations of elastic properties of alloys with mechanical instability: Application to BCC Ti-V alloys2018In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 140, p. 357-365Article in journal (Refereed)
    Abstract [en]

    Considering Ti-V alloys with the body-centered cubic crystal lattice, a system with mechanical instability for Tirich alloys, we calculate their elastic properties using Projector Augmented Wave method and the exact muffin tin orbital method in a complete interval of V concentrations. The substitutional disorder is modeled using the special quasi-random structures technique and the coherent potential approximation. The efficiency and accuracy of the simulation techniques is analyzed, and a strategy for efficient high-throughput calculations of elastic properties of disordered alloys is proposed. Dependences of the single crystal elastic moduli on V concentration and a set ofmechanical characteristics of polycrystalline alloys are presented and discussed. The effect of V content on themechanical stabilization of the bcc Ti-V alloys is investigated. In agreement with experiment, we find that titanium-rich alloys are mechanically unstable, however the alloys becomemechanically stablewith increasing content of V in the system. We observe a nonlinear dependence of the alloys Youngs moduli in a vicinity of the mechanical stabilization and suggest that this effect can be used to design alloys with low values of the elastic moduli. (C) 2017 Elsevier Ltd. All rights reserved.

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  • 181.
    Tasnadi, Ferenc
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Abrikosov, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Ab initio elastic tensor of cubic Ti0.5Al0.5N alloys: Dependence of elastic constants on size and shape of the supercell model and their convergence2012In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 85, no 14, p. 144112-Article in journal (Refereed)
    Abstract [en]

    In this study we discuss the performance of the special quasirandom structure (SQS) method in predicting the elastic properties of B1 (rocksalt) Ti0.5Al0.5N alloy. We use a symmetry-based projection technique, which gives the closest cubic approximate of the elastic tensor and allows us to align the SQSs of different shapes and sizes for a comparison in modeling elastic tensors. We show that the derived closest cubic approximate of the elastic tensor converges faster with respect to SQS size than the elastic tensor itself. That establishes a less demanding computational strategy to achieve convergence for the elastic constants. We determine the cubic elastic constants (C-ij) and Zeners type elastic anisotropy (A) of Ti0.5Al0.5N. Optimal supercells, which capture accurately both the configurational disorder and cubic symmetry of elastic tensor, result in C-11 = 447 GPa, C-12 = 158 GPa, and C-44 = 203 GPa with 3% of error and A = 1.40 with 6% of error. In addition, we establish the general importance of selecting proper SQS with symmetry arguments to reliably model elasticity of alloys. We suggest the calculation of nine elastic tensor elements: C-11, C-22, C-33, C-12, C-13, C-23, C-44, C-55, and C-66, to analyze the performance of SQSs and predict elastic constants of cubic alloys. The described methodology is general enough to be extended for alloys with other symmetry at arbitrary composition.

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  • 182. Order onlineBuy this publication >>
    Gambino, Davide
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Ab Initio Modeling of Magnetic Materials in the High-Temperature Paramagnetic Phase2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The modeling of magnetic materials at finite temperatures is an ongoing challenge in the field of theoretical physics. This field has strongly benefited from the development of computational methods, which allow to predict material’s properties and explain physical effects on the atomic scale, and are now employed to direct the design of new materials. However, simulations need to be as accurate as possible to give reliable insights into solid-state phenomena, which means that, most desirably, all competing effects occurring in a system at realistic conditions should be included. This task is particularly difficult in the modeling of magnetic materials from first principles, due to the quantum nature of magnetism and its interplay with other phenomena related to the atomic degrees of freedom. The aim of this thesis is therefore to develop methods that enable the inclusion of magnetic effects in finite temperature simulations based on density functional theory (DFT), while considering on the same footing vibrational and structural degrees of freedom,with a particular focus on the high-temperature paramagnetic phase. The type of couplings investigated in this thesis can be separated in two big categories: interplay between magnetism and structure, and between magnetism and vibrations.

    Regarding the former category, I have tried to shine some light on the effect of the paramagnetic state on atomic positions in a crystal in the presence of defects or for complicated systems, as opposed to the ordered magnetic state. To model the high-temperature paramagnetic phase of magnetic materials, the disordered local moment (DLM) approach is employed in the whole work. In this framework, I have developed a method to perform local lattice relaxations in the disordered magnetic state, which consists of a step-wise partial relaxation of the atomic positions, while changing the configuration of the magnetic moments at each step of the procedure. This method has been tested on point defects in paramagnetic bcc Fe, namely the single vacancy and, separately, the C interstitial in octahedral position, and on Fe1-xCralloys, finding non-negligible effects on formation energies. In addition, the feasibility of investigating extended defects like dislocations in the paramagnetic state with this method has also been proven by studying the screw dislocation in bcc Fe. The DLM-relaxation method has then been used to investigate intrinsic and extrinsic defects in CrN, an antiferromagnetic semiconductor studied for thermoelectric applications, found in the paramagnetic state at operating temperature, and a newly synthesized compound, Fe3CO7, which features a complicated crystal structure and unusual electronic properties, with possible important implications for the chemistry of Earth’s mantle.

    The other focus of this thesis is the coupling between magnetism and lattice vibrations. As a pre-step to perform fully coupled atomistic spin dynamics-ab initio molecular dynamics (ASD-AIMD) simulations, I have first investigated the effect of vibrations on the so called longitudinal spin fluctuations, a mechanism occurring at finite temperatures and important for itinerant electron magnetic systems. I have developed a framework to investigate the dependence of the local moment’s energy landscapes on the instantaneous positions of the atoms, testing it on Fe at different temperature and pressure conditions. This study has laid the foundation to apply machine learning techniques to the prediction of the energy landscapes during an ASD-AIMD simulation. Finally, I have investigated the phase stability of Fe at ambient pressure from the theoretical Curie temperature up to its melting point with ASD-AIMD. This task is carried out by applying a pool of thermodynamic techniques to calculate free energy differences, and therefore I have defined a strategy to discern the thermodynamic equilibrium structure in magnetic materials in the high temperature paramagnetic phase based on first principles dynamical simulations. The methodologies developed and applied in this work constitute an improvement towards the simulation of magnetic materials accounting for the coupling of all effects, and the hope is to bridge a gap between theory and experiments.

    List of papers
    1. Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN
    Open this publication in new window or tab >>Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN
    2017 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, no 10, article id 104306Article in journal (Refereed) Published
    Abstract [en]

    We use the color diffusion (CD) algorithm in nonequilibrium (accelerated) ab initio molecular dynamics simulations to determine Ti monovacancy jump frequencies in NaCl-structure titanium nitride (TiN), at temperatures ranging from 2200 to 3000 K. Our results showthat theCDmethod extended beyond the linear-fitting rate-versus-force regime [Sangiovanni et al., Phys. Rev. B 93, 094305 (2016)] can efficiently determine metal vacancy migration rates in TiN, despite the low mobilities of lattice defects in this type of ceramic compound. We propose a computational method based on gamma-distribution statistics, which provides unambiguous definition of nonequilibrium and equilibrium (extrapolated) vacancy jump rates with corresponding statistical uncertainties. The acceleration-factor achieved in our implementation of nonequilibrium molecular dynamics increases dramatically for decreasing temperatures from 500 for T close to the melting point T-m, up to 33 000 for T approximate to 0.7 T-m

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2017
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-141712 (URN)10.1103/PhysRevB.96.104306 (DOI)000411076000005 ()
    Note

    Funding Agencies|Swedish Foundation for Strategic Research (SSF) project SRL [10-0026]; Swedish Research Council (VR) [621-2011-4417, 2015-04391, 330-2014-6336]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials [MatLiU 2009-00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Marie Sklodowska Curie Actions [INCA 600398]; Swedish Foundation for Strategic Research; Stiftelsen Olle Engkvist Byggmastare

    Available from: 2017-10-05 Created: 2017-10-05 Last updated: 2024-01-08
    2. Lattice relaxations in disordered Fe-based materials in the paramagnetic state from first principles
    Open this publication in new window or tab >>Lattice relaxations in disordered Fe-based materials in the paramagnetic state from first principles
    2018 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 98, no 6, article id 064105Article in journal (Refereed) Published
    Abstract [en]

    The first-principles calculation of many material properties, in particular related to defects and disorder, starts with the relaxation of the atomic positions of the system under investigation. This procedure is routine for nonmagnetic and magnetically ordered materials. However, when it comes to magnetically disordered systems, in particular the paramagnetic phase of magnetic materials, it is not clear how the relaxation procedure should be performed or which geometry should be used. Here we propose a method for the structural relaxation of magnetic materials in the paramagnetic regime, in an adiabatic fast-magnetism approximation within the disordered local moment (DLM) picture in the framework of density functional theory. The method is straightforward to implement using any ab initio code that allows for structural relaxations. We illustrate the importance of considering the disordered magnetic state during lattice relaxations by calculating formation energies and geometries for an Fe vacancy and C insterstitial atom in body-centered cubic (bcc) Fe as well as bcc Fe1-xCrx random alloys in the paramagnetic state. In the vacancy case, the nearest neighbors to the vacancy relax toward the vacancy of 0.14 angstrom (-5% of the ideal bcc nearest-neighbor distance), which is twice as large as the relaxation in the ferromagnetic case. The vacancy formation energy calculated in the DLM state on these positions is 1.60 eV, which corresponds to a reduction of about 0.1 eV compared to the formation energy calculated using DLM but on ferromagnetic-relaxed positions. The carbon interstitial formation energy is found to be 0.41 eV when the DLM relaxed positions are used, as compared to 0.59 eV when the FM-relaxed positions are employed. For bcc Fe0.5Cr0.5 alloys, the mixing enthalpy is reduced by 5 meV/atom, or about 10%, when the DLM state relaxation is considered, as compared to positions relaxed in the ferromagnetic state.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2018
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-151199 (URN)10.1103/PhysRevB.98.064105 (DOI)000443139600004 ()
    Note

    Funding Agencies|Swedish Research Council (VR) [2014-6336]; Marie Sklodowska Curie Actions, Cofund [INCA 600398]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMatLiU) [2009 00971]; Swedish Foundation for Strategic Research

    Available from: 2018-09-13 Created: 2018-09-13 Last updated: 2021-08-13
    3. Assessing the SCAN functional for itinerant electron ferromagnets
    Open this publication in new window or tab >>Assessing the SCAN functional for itinerant electron ferromagnets
    Show others...
    2018 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 98, no 9, article id 094413Article in journal (Refereed) Published
    Abstract [en]

    Density functional theory is a standard model for condensed-matter theory and computational material science. The accuracy of density functional theory is limited by the accuracy of the employed approximation to the exchange-correlation functional. Recently, the so-called strongly constrained appropriately normed (SCAN) [Sun, Ruzsinszky, and Perdew, Phys. Rev. Lett. 115, 036402 (2015)] functional has received a lot of attention due to promising results for covalent, metallic, ionic, as well as hydrogen- and van der Waals-bonded systems alike. In this work, we focus on assessing the performance of the SCAN functional for itinerant magnets by calculating basic structural and magnetic properties of the transition metals Fe, Co, and Ni. We find that although structural properties of bcc-Fe seem to be in good agreement with experiment, SCAN performs worse than standard local and semilocal functionals for fcc-Ni and hcp-Co. In all three cases, the magnetic moment is significantly overestimated by SCAN, and the 3d states are shifted to lower energies, as compared to experiments.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2018
    National Category
    Theoretical Chemistry
    Identifiers
    urn:nbn:se:liu:diva-151640 (URN)10.1103/PhysRevB.98.094413 (DOI)000444348500004 ()
    Note

    Funding Agencies|Swedish e-Science Research Centre (SeRC); Swedish Research Council (VR) through the International Career Grant [20146336]; Marie Sklodowska CurieActions, Cofund, Project [INCA 600398]; Swedish Foundation for Strategic Research (SSF) through the Future Research Leaders 6 program; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; competence center FunMat-II - Vinnova [201605156]; Russian Science Foundation [18-12-00492]

    Available from: 2018-09-27 Created: 2018-09-27 Last updated: 2024-01-08
    4. Superioniclike Diffusion in an Elemental Crystal: bcc Titanium
    Open this publication in new window or tab >>Superioniclike Diffusion in an Elemental Crystal: bcc Titanium
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    2019 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 123, no 10, article id 105501Article in journal (Refereed) Published
    Abstract [en]

    Recent theoretical investigations [A. B. Belonoshko et aL Nat. Geosci. 10, 312 (2017)] revealed the occurrence of the concerted migration of several atoms in bcc Fe at inner-core temperatures and pressures. Here, we combine first-principles and semiempirical atomistic simulations to show that a diffusion mechanism analogous to the one predicted for bcc iron at extreme conditions is also operative and of relevance for the high-temperature bcc phase of pure Ti at ambient pressure. The mechanism entails a rapid collective movement of numerous (from two to dozens) neighbors along tangled closed-loop paths in defect-free crystal regions. We argue that this phenomenon closely resembles the diffusion behavior of superionics and liquid metals. Furthermore, we suggest that concerted migration is the atomistic manifestation of vanishingly small co-mode phonon frequencies previously detected via neutron scattering and the mechanism underlying anomalously large and markedly non-Arrhenius self-diffusivities characteristic of bcc Ti.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2019
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-160393 (URN)10.1103/PhysRevLett.123.105501 (DOI)000483587200007 ()
    Note

    Funding Agencies|Olle Engkvist Foundation; Swedish Research Council (VR) [2015-04391, 2014-4750]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMat-LiU) [2009-00971]; VINN Excellence Center Functional Nanoscale Materials (FunMat-2) [2016-05156]

    Available from: 2019-09-23 Created: 2019-09-23 Last updated: 2024-01-08
    5. Longitudinal spin fluctuations in bcc and liquid Fe at high temperature and pressure calculated with a supercell approach
    Open this publication in new window or tab >>Longitudinal spin fluctuations in bcc and liquid Fe at high temperature and pressure calculated with a supercell approach
    Show others...
    2020 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 102, no 1, article id 014402Article in journal (Refereed) Published
    Abstract [en]

    Investigating magnetic materials at realistic conditions with first-principles methods is a challenging task due to the interplay of vibrational and magnetic degrees of freedom. The most difficult contribution to include in simulations is represented by the longitudinal magnetic degrees of freedom [longitudinal spin fluctuation (LSF)] due to their inherent many-body nature; nonetheless, schemes that enable to take into account this effect on a semiclassical level have been proposed and employed in the investigation of magnetic systems. However, assessment of the effect of vibrations on LSF is lacking in the literature. For this reason, in this work we develop a supercell approach within the framework of constrained density functional theory to calculate self-consistently the size of local-environment-dependent magnetic moments in the paramagnetic, high-temperature state in the presence of lattice vibrations and for liquid Fe in different conditions. First, we consider the case of bcc Fe at the Curie temperature and ambient pressure. Then, we perform a similar analysis on bcc Fe at Earths inner-core conditions, and we find that LSFs stabilize nonzero moments which affect atomic forces and the electronic density of states of the system. Finally, we employ the present scheme on liquid Fe at the melting point at ambient pressure and at Earths outer-core conditions (p approximate to 200 GPa, T approximate to 6000 K). In both cases, we obtain local magnetic moments of sizes comparable to the solid-state counterparts.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2020
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-174528 (URN)10.1103/PhysRevB.102.014402 (DOI)000544842300002 ()
    Note

    Funding Agencies|Swedish Research Council (VR) through International Career GrantSwedish Research Council [2014-6336, 2019-05403]; Marie Sklodowska Curie Actions [INCA 600398]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Knut and Alice Wallenberg Foundation (Wallenberg Scholar Grant) [KAW-2018.0194]; Swedish Foundation for Strategic Research through the Future Research Leaders 6 program [FFL 15-0290]

    Available from: 2021-03-22 Created: 2021-03-22 Last updated: 2021-08-13Bibliographically approved
    6. Screw dislocation core structure in the paramagnetic state of bcc iron from first-principles calculations
    Open this publication in new window or tab >>Screw dislocation core structure in the paramagnetic state of bcc iron from first-principles calculations
    2020 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 102, no 9, article id 094420Article in journal (Refereed) Published
    Abstract [en]

    Iron-based alloys are widely used as structural components in engineering applications. This calls for a fundamental understanding of their mechanical properties, including those of pure iron. Under operational temperatures the mechanical and magnetic properties will differ from those of ferromagnetic body-centered-cubic iron at 0 K. In this theoretical work we study the effect of disordered magnetism on the screw dislocation core structure and compare with results for the ordered ferromagnetic case. Dislocation cores control some local properties such as the choice of glide plane and the associated dislocation mobility. Changes in the magnetic state can lead to modifications in the structure of the core and affect dislocation mobility. In particular, we focus on the core properties of the 1/2 < 111 > screw dislocation in the paramagnetic state. Using the noncollinear disordered local moment approximation to address paramagnetism, we perform structural relaxations within density functional theory. We obtain the dislocation core structure for the easy and hard cores in the paramagnetic state, and compare them with their ferromagnetic counterparts. By averaging the energy of several disordered magnetic configurations, we obtain an energy difference between the easy- and hard-core configurations, with a lower, but statistically close, value than the one reported for the ferromagnetic case. The magnetic moment and atomic volume at the dislocation core differ between paramagnetic and ferromagnetic states, with possible consequences on the temperature dependence of defect-dislocation interactions.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2020
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-170637 (URN)10.1103/PhysRevB.102.094420 (DOI)000569624900005 ()
    Note

    Funding Agencies|Swedish Research Council (VR)Swedish Research Council [2014-6336, 2019-05403]; Marie Sklodowska Curie Actions [INCA 600398]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMatLiU) [2009 00971]; Knut and Alice Wallenberg Foundation (Wallenberg Scholar Grant) [KAW-2018.0194]; Swedish Foundation for Strategic Research through the Future Research Leaders 6 program [FFL 15-0290]

    Available from: 2020-10-31 Created: 2020-10-31 Last updated: 2021-08-13
    7. High thermoelectric power factor of pure and vanadium-alloyed chromium nitride thin films
    Open this publication in new window or tab >>High thermoelectric power factor of pure and vanadium-alloyed chromium nitride thin films
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    2021 (English)In: Materials Today Communications, ISSN 2352-4928, Vol. 28, article id 102493Article in journal (Refereed) Published
    Abstract [en]

    Chromium-nitride based materials have shown unexpected promise as thermo-electric materials for, e.g., wasteheat harvesting. Here, CrN and (Cr,V)N thin films were deposited by reactive magnetron sputtering. Thermoelectric measurements of pure CrN thin films show a low electrical resistivity between 1.2 and 1.5 x 10(-3) Omega cm and very high values of the Seebeck coefficient and thermoelectric power factor, in the range between 370-430 mu V/K and 9-11 x 10(-3) W/mK(2), respectively. Alloying of CrN films with small amounts (less than 15 %) of vanadium results in cubic (Cr,V)N thin films. Vanadium decreases the electrical resistivity and yields powerfactor values in the same range as pure CrN. Density functional theory calculations of sub-stoichiometric CrN1-delta and (Cr,V)N1-delta show that nitrogen vacancies and vanadium substitution both cause n-type conductivity and features in the band structure typically correlated with a high Seebeck coefficient. The results suggest that slight variations in nitrogen and vanadium content affect the power factor and offers a means of tailoring the power factor and thermoelectric figure of merit.

    Place, publisher, year, edition, pages
    ELSEVIER, 2021
    Keywords
    Transition-metal nitrides; Sputter deposition; Thermoelectrics; Density functional theory; Energy harvesting
    National Category
    Materials Engineering Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-178234 (URN)10.1016/j.mtcomm.2021.102493 (DOI)000707388200007 ()
    Note

    Funding: Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Knut and Alice Wallenberg foundation through the Wallenberg Academy Fellows program [KAW-2020.0196]; Swedish Research Council (VR)Swedish Research Council [2019-05403, 2016-03365]; Swedish Foundation for Strategic Research through the Future Research Leaders 6 program [FFL 15-0290]; Knut and Alice Wallenberg Foundation (Wallenberg Scholar Grant) [KAW2018.0194]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [2018-05973]

    Available from: 2021-08-18 Created: 2021-08-18 Last updated: 2022-04-05
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  • 183.
    Berglund, Ulf
    et al.
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Nilsson, Lennart
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Janzon, Magnus
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Abciximab bolus with optional infusion in intervention for ST-elevation myocardial infarction2013In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 47, no 4, p. 230-235Article in journal (Refereed)
    Abstract [en]

    Objectives. The standard abciximab regimen is a bolus dose followed by a 12-h infusion. Whether the bolus dose alone is sufficient for ST-elevation myocardial infarction patients receiving a high loading dose of clopidogrel is unknown. Design. In an observational study, 693 consecutive patients were treated with abciximab during percutaneous coronary intervention for ST-elevation myocardial infarction. Totally 354 patients received standard strategy of abciximab bolus and infusion followed by 339 patients that recieved abciximab bolus only (271 patients) or bolus and infusion if suboptimal result (68 patients) in combination with a higher loading dose of clopidogrel (600 mg) the modified strategy. Results. The two groups were similar regarding baseline characteristics and in hospital bleeding events. At 30 days, the composite of death, re-infarction or target vessel revascularization was 9.1% in the standard and 7.5% in the modified strategy (p = 0.45). The rate of stent thrombosis was lower in the modified strategy group with 0% and 2.3% in the standard group (pandlt;0.001) and the mean total medical cost was lower in the modified strategy group with 8032 and 8665 in the standard group (pandlt;0.001). Conclusions. In primary percutaneous coronary intervention with a loading dose of 600 mg clopidogrel, it seems safe and cost-saving to give abciximab bolus with optional infusion.

  • 184.
    Granath, Simon
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Krantz, Gustav
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Abnormal avkastning under olika konjunkturfaser på Stockholmsbörsen: En studie om överreaktioner vid stora kursförändringar2017Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The efficient market hypothesis is one of the central aspects in financial research which assumes that assets are correctly priced from all available information and that the only way to achieve abnormal return is for investors to expose themselves to more risk. This gives an incentive to investigate whether there are other ways to achieve this. One method could be through De Bondt and Thalers (1985) contrarian strategy, which means that investors buy oversold stocks. The other way around goes for overbought stocks, in which investors consequently short them. There is however a variation in the research whether this method is proven valid or not. Another unexplored subject is regarding its validity in different business cycles. The purpose of this study is to explore if overreactions exists at the Swedish stock index OMXS30. This will be based on substantial daily price movements and whether these potential overreactions differ through the business cycle. Data on all companies included in the index from 1996 to 2017 was analyzed through an event study with an estimation window of 20 days and 50 days post event window.The main findings of this study show that loser stocks did overreact but that winner stocks in an opposite way underreacted. This means that both samples had a positive abnormal return. This abnormal return was substantially higher during recessions than expansions, which indicates that the business cycle has an important role when studying overreactions.

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  • 185.
    Carlsson, Annelie
    et al.
    Lund Univ, Sweden.
    Shepherd, Maggie
    Univ Exeter, England.
    Ellard, Sian
    Univ Exeter, England; Royal Devon and Exeter NHS Fdn Trust, England.
    Weedon, Michael
    Univ Exeter, England.
    Lernmark, Ake
    Lund Univ, Sweden.
    Forsander, Gun
    Sahlgrens Univ Hosp, Sweden; Univ Gothenburg, Sweden.
    Colclough, Kevin
    Royal Devon and Exeter NHS Fdn Trust, England.
    Brahimi, Qefsere
    Lund Univ, Sweden.
    Valtonen-Andre, Camilla
    Univ and Reg Labs Reg, Sweden.
    Ivarsson, Sten A.
    Lund Univ, Sweden.
    Elding Larsson, Helena
    Lund Univ, Sweden.
    Samuelsson, Ulf
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Children's and Women's Health. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, H.K.H. Kronprinsessan Victorias barn- och ungdomssjukhus.
    Ortqvist, Eva
    Karolinska Inst, Sweden.
    Groop, Leif
    Univ Helsinki, Finland.
    Ludvigsson, Johnny
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Children's and Women's Health. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, H.K.H. Kronprinsessan Victorias barn- och ungdomssjukhus.
    Marcus, Claude
    Karolinska Inst, Sweden.
    Hattersley, Andrew T.
    Univ Exeter, England.
    Absence of Islet Autoantibodies and Modestly Raised Glucose Values at Diabetes Diagnosis Should Lead to Testing for MODY: Lessons From a 5-Year Pediatric Swedish National Cohort Study2020In: Diabetes Care, ISSN 0149-5992, E-ISSN 1935-5548, Vol. 43, no 1, p. 82-89Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE Identifying maturity-onset diabetes of the young (MODY) in pediatric populations close to diabetes diagnosis is difficult. Misdiagnosis and unnecessary insulin treatment are common. We aimed to identify the discriminatory clinical features at diabetes diagnosis of patients with glucokinase (GCK), hepatocyte nuclear factor-1A (HNF1A), and HNF4A MODY in the pediatric population.

    RESEARCH DESIGN AND METHODS Swedish patients (n = 3,933) aged 1–18 years, diagnosed with diabetes May 2005 to December 2010, were recruited from the national consecutive prospective cohort Better Diabetes Diagnosis. Clinical data, islet autoantibodies (GAD insulinoma antigen-2, zinc transporter 8, and insulin autoantibodies), HLA type, and C-peptide were collected at diagnosis. MODY was identified by sequencing GCKHNF1A, and HNF4A, through either routine clinical or research testing.

    RESULTS The minimal prevalence of MODY was 1.2%. Discriminatory factors for MODY at diagnosis included four islet autoantibody negativity (100% vs. 11% not-known MODY; P = 2 × 10−44), HbA1c (7.0% vs. 10.7% [53 vs. 93 mmol/mol]; P = 1 × 10−20), plasma glucose (11.7 vs. 26.7 mmol/L; P = 3 × 10−19), parental diabetes (63% vs. 12%; P = 1 × 10−15), and diabetic ketoacidosis (0% vs. 15%; P = 0.001). Testing 303 autoantibody-negative patients identified 46 patients with MODY (detection rate 15%). Limiting testing to the 73 islet autoantibody-negative patients with HbA1c <7.5% (58 mmol/mol) at diagnosis identified 36 out of 46 (78%) patients with MODY (detection rate 49%). On follow-up, the 46 patients with MODY had excellent glycemic control, with an HbA1c of 6.4% (47 mmol/mol), with 42 out of 46 (91%) patients not on insulin treatment.

    CONCLUSIONS At diagnosis of pediatric diabetes, absence of all islet autoantibodies and modest hyperglycemia (HbA1c <7.5% [58 mmol/mol]) should result in testing for GCK, HNF1A, and HNF4A MODY. Testing all 12% patients negative for four islet autoantibodies is an effective strategy for not missing MODY but will result in a lower detection rate. Identifying MODY results in excellent long-term glycemic control without insulin.

  • 186.
    Liss, Erik
    et al.
    Linköping University, The Institute for Analytical Sociology, IAS. Linköping University, Faculty of Arts and Sciences. Ratio Institute, Stockholm.
    Korpi, Martin
    Ratio institute, Stockholm; EHFF, Stockholm School of Economics.
    Wennberg, Karl
    Linköping University, Department of Management and Engineering, The Institute for Analytical Sociology, IAS. Linköping University, Faculty of Arts and Sciences. Ratio institute, Stockholm; Stockholm School of Economics.
    Absolute income mobility and the effect of parent generation inequality: An extended decomposition approach2023In: European Economic Review, ISSN 0014-2921, E-ISSN 1873-572X, Vol. 152, article id 104359Article in journal (Refereed)
    Abstract [en]

    We use full-population data to study trends in intergenerational absolute income mobility, measured as the ratio of children earning more than their parents, for 11 Swedish cohorts born 1972–1983. Absolute mobility during this period increases from 72% to 84% for men and from 76% to 86% for women—higher figures than in most other countries studied. To explain these results, we outline a novel decomposition strategy that accounts for cohort variation in parent-generation income inequality. All else equal, if income inequality is higher in the parent generation, more economic growth is required to achieve any given level of absolute mobility. We discuss implications for comparative research in intergenerational income mobility.

  • 187.
    Nilsson, Ulf
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Abstract interpretations and abstract machines: contributions to a methodology for the implementation of logic programs1992Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Because of the conceptual gap between high-level logic programming languages and existing hardware, the problem of compilation is hard. This thesis addresses two ways of narrowing this gap – program analysis through abstract interpretation and the introduction of intermediate languages and abstract machines.

    By means of abstract interpretations it is possible to infer program properties which are not explicitly represented in the program – properties that can be used by a compiler to generate specialized code. We describe a framework for constructing and computing abstract interpretations of logic programs with equality. The core of the framework is an abstract interpretation called the base interpretation which provides a model of the run-time behaviour of the program. The model characterized by the base interpretation consists of the set of all reachable computation states of a transition system specifying an operational semantics reminiscent of SLD-resolution. This model is in general not effectively computable. However, the base interpretation can be used for constructing new abstract interpretations which approximate this model. Our base interpretation combines both a simple and concise formulation. with the ability of inferring a wide range of program properties. The framework supports a variety of computation strategies including, in particular, efficient computing of approximate models using a chaotic iteration strategy.

    We also show that abstract interpretations may form a basis for implementation of deductive data bases. We relate the magic templates approach to bottom-up evaluation of deductive databases with the base interpretation of C. Mellish and prove that they not only specify isomorphic models but also that the computations which lead up to those models are isomorphic. This implies that methods (for instance, evaluation and transformation techniques) which are applicable in one of the fields are also applicable in the other. As a side-effect we are also able to relate so-called "top-down" and "bottom-up" abstract interpretations.

    Abstract machines and intermediate languages are often used to bridge the conceptual gap between language and hardware. Unfortunately – because of the way they are presented – it is often difficult to see the relationship between the high-level and intermediate language. In the final part of the thesis we propose a methodology for designing abstract machines for logic programming languages in such a way that much of the relationship is preserved throughout the process. Using partial deduction and other transformation techniques, a source program and an interpreter are "compiled" into a new program consisting of "machine code" for the source program and an abstract machine for the machine code. Based upon the appearance of the abstract machine the user may choose to modify the interpreter and repeat the process until the abstract machine reaches a suitable level of abstraction. We demonstrate how these techniques can be applied to derive several of the control instructions of Warren's Abstract Machine, thus complementing previous work by P. Kursawe who reconstructed several of the unification instructions using similar techniques.

  • 188.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Abstract Syntax Can Make the Definition of Modelica Less Abstract2007In: Proceedings of the 1st International Workshop on Equation-Based Object-Oriented Languages and Tools, Berlin, Germany, 2007, p. 111-126Conference paper (Refereed)
    Abstract [en]

    Modelica is an open standardized language used for modeling and simulation of complex physical systems. The language specification defines a formal concrete syntax, but the semantics is informally described using natural language. The latter makes the language hard to interpret, maintain and reason about, which affect both tool development and language evolution. Even if a completely formal semantics of the Modelica language can be seen as a natural goal, it is a well-known fact that defining understandable and concise formal semantics specifications for large and complex languages is a very hard problem. In this paper, we will discuss different aspects of formulating a Modelica specification; both in terms of what should be specified and how it can be done. Moreover, we will further argue that a “middle-way” strategy can make the specification both clearer and easier to reason about. A proposal is outlined, where the current informally specified semantics is complemented with several grammars, specifying intermediate representations of abstract syntax. We believe that this kind of evolutionary strategy is easier to gain acceptance for, and is more realistic in the short-term, than a revolutionary approach of using a fully formal semantics definition of the language.

  • 189.
    Hedtjärn, Håkan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radio Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Alm Carlsson, Gudrun
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radio Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Williamson, Jeffrey
    Accelerated Monte Carlo-based dose calculations for brachytherapy planning using correlated sampling.2000In: Digest of papers of the 2000 world congress on medical physics. CD-Rom Chicago July 23-28,2000, IEEE , 2000, p. 372-375 vol. 1Conference paper (Refereed)
    Abstract [en]

    Correlated sampling is evaluated as a strategy for accelerating Monte Carlo photon transport (MCPT) simulation for use as a practical patient-specific treatment-planning tool. Correlated MCPT simulation was shown to offer substantial efficiency gains over conventional MCPT simulation for selected parts of the 3D volume but was not sufficient to improve MCPT simulation everywhere

  • 190. Order onlineBuy this publication >>
    Dahlin, Johan
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Accelerating Monte Carlo methods for Bayesian inference in dynamical models2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Making decisions and predictions from noisy observations are two important and challenging problems in many areas of society. Some examples of applications are recommendation systems for online shopping and streaming services, connecting genes with certain diseases and modelling climate change. In this thesis, we make use of Bayesian statistics to construct probabilistic models given prior information and historical data, which can be used for decision support and predictions. The main obstacle with this approach is that it often results in mathematical problems lacking analytical solutions. To cope with this, we make use of statistical simulation algorithms known as Monte Carlo methods to approximate the intractable solution. These methods enjoy well-understood statistical properties but are often computational prohibitive to employ.

    The main contribution of this thesis is the exploration of different strategies for accelerating inference methods based on sequential Monte Carlo (SMC) and Markov chain Monte Carlo (MCMC). That is, strategies for reducing the computational effort while keeping or improving the accuracy. A major part of the thesis is devoted to proposing such strategies for the MCMC method known as the particle Metropolis-Hastings (PMH) algorithm. We investigate two strategies: (i) introducing estimates of the gradient and Hessian of the target to better tailor the algorithm to the problem and (ii) introducing a positive correlation between the point-wise estimates of the target.

    Furthermore, we propose an algorithm based on the combination of SMC and Gaussian process optimisation, which can provide reasonable estimates of the posterior but with a significant decrease in computational effort compared with PMH. Moreover, we explore the use of sparseness priors for approximate inference in over-parametrised mixed effects models and autoregressive processes. This can potentially be a practical strategy for inference in the big data era. Finally, we propose a general method for increasing the accuracy of the parameter estimates in non-linear state space models by applying a designed input signal.

    List of papers
    1. Particle Metropolis-Hastings using gradient and Hessian information
    Open this publication in new window or tab >>Particle Metropolis-Hastings using gradient and Hessian information
    2015 (English)In: Statistics and computing, ISSN 0960-3174, E-ISSN 1573-1375, Vol. 25, no 1, p. 81-92Article in journal (Refereed) Published
    Abstract [en]

    Particle Metropolis-Hastings (PMH) allows for Bayesian parameter inference in nonlinear state space models by combining MCMC and particle filtering. The latter is used to estimate the intractable likelihood. In its original formulation, PMH makes use of a marginal MCMC proposal for the parameters, typically a Gaussian random walk. However, this can lead to a poor exploration of the parameter space and an inefficient use of the generated particles.

    We propose two alternative versions of PMH that incorporate gradient and Hessian information about the posterior into the proposal. This information is more or less obtained as a byproduct of the likelihood estimation. Indeed, we show how to estimate the required information using a fixed-lag particle smoother, with a computational cost growing linearly in the number of particles. We conclude that the proposed methods can: (i) decrease the length of the burn-in phase, (ii) increase the mixing of the Markov chain at the stationary phase, and (iii) make the proposal distribution scale invariant which simplifies tuning.

    Place, publisher, year, edition, pages
    Springer, 2015
    National Category
    Control Engineering Signal Processing Probability Theory and Statistics
    Identifiers
    urn:nbn:se:liu:diva-106749 (URN)10.1007/s11222-014-9510-0 (DOI)000349028500013 ()
    Projects
    Probabilistic modelling of dynamical systems
    Funder
    Swedish Research Council, 621-2013-5524
    Note

    On the day of the defence date the status of this article was Manuscript.

    Available from: 2014-05-21 Created: 2014-05-21 Last updated: 2019-12-02Bibliographically approved
    2. Quasi-Newton particle Metropolis-Hastings
    Open this publication in new window or tab >>Quasi-Newton particle Metropolis-Hastings
    2015 (English)In: Proceedings of the 17th IFAC Symposium on System Identification., Elsevier, 2015, Vol. 48 Issue 28, p. 981-986Conference paper, Published paper (Refereed)
    Abstract [en]

    Particle Metropolis-Hastings enables Bayesian parameter inference in general nonlinear state space models (SSMs). However, in many implementations a random walk proposal is used and this can result in poor mixing if not tuned correctly using tedious pilot runs. Therefore, we consider a new proposal inspired by quasi-Newton algorithms that may achieve similar (or better) mixing with less tuning. An advantage compared to other Hessian based proposals, is that it only requires estimates of the gradient of the log-posterior. A possible application is parameter inference in the challenging class of SSMs with intractable likelihoods.We exemplify this application and the benefits of the new proposal by modelling log-returns offuture contracts on coffee by a stochastic volatility model with alpha-stable observations.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keywords
    Bayesian parameter inference; state space models; approximate Bayesian computations; particle Markov chain Monte Carlo; α-stable distributions
    National Category
    Control Engineering Probability Theory and Statistics
    Identifiers
    urn:nbn:se:liu:diva-123666 (URN)10.1016/j.ifacol.2015.12.258 (DOI)
    Conference
    Proceedings of the 17th IFAC Symposium on System Identification, Beijing, China, October 19-21, 2015.
    Projects
    CADICS
    Funder
    Swedish Research Council, 637-2014-466Swedish Research Council, 621-2013-5524
    Available from: 2016-01-07 Created: 2016-01-07 Last updated: 2016-04-01
    3. Hierarchical Bayesian approaches for robust inference in ARX models
    Open this publication in new window or tab >>Hierarchical Bayesian approaches for robust inference in ARX models
    2012 (English)In: Proceedings from the 16th IFAC Symposium on System Identification, 2012 / [ed] Michel Kinnaert, International Federation of Automatic Control , 2012, Vol. 16 Part 1, p. 131-136Conference paper, Oral presentation only (Refereed)
    Abstract [en]

    Gaussian innovations are the typical choice in most ARX models but using other distributions such as the Student's t could be useful. We demonstrate that this choice of distribution for the innovations provides an increased robustness to data anomalies, such as outliers and missing observations. We consider these models in a Bayesian setting and perform inference using numerical procedures based on Markov Chain Monte Carlo methods. These models include automatic order determination by two alternative methods, based on a parametric model order and a sparseness prior, respectively. The methods and the advantage of our choice of innovations are illustrated in three numerical studies using both simulated data and real EEG data.

    Place, publisher, year, edition, pages
    International Federation of Automatic Control, 2012
    Series
    IFAC papers online, ISSN 1474-6670 ; 2012
    Keywords
    Particle Filtering/Monte Carlo Methods; Bayesian Methods
    National Category
    Signal Processing
    Identifiers
    urn:nbn:se:liu:diva-81258 (URN)10.3182/20120711-3-BE-2027.00318 (DOI)978-3-902823-06-9 (ISBN)
    Conference
    The 16th IFAC Symposium on System Identification, July 11-13, Brussels, Belgium
    Projects
    CADICSCNDS
    Funder
    Swedish Research Council
    Available from: 2012-09-10 Created: 2012-09-10 Last updated: 2016-05-04Bibliographically approved
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  • 191.
    Kasten, Jens
    et al.
    IVU Traff Technology AG, Germany; Zuse Institute Berlin, Germany.
    Reininghaus, Jan
    IST Austria, Austria.
    Hotz, Ingrid
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Hege, Hans-Christian
    Zuse Institute Berlin, Germany.
    Noack, Bernd R.
    LIMSI CNRS, France; Technical University of Carolo Wilhelmina Braunschweig, Germany.
    Daviller, Guillaume
    CNRS, France.
    Morzynski, Marek
    Poznan University of Tech, Poland.
    Acceleration feature points of unsteady shear flows2016In: ARCHIVES OF MECHANICS, ISSN 0373-2029, Vol. 68, no 1, p. 55-80Article in journal (Refereed)
    Abstract [en]

    A FRAMEWORK FOR EXTRACTING FEATURES IN 2D TRANSIENT FLOWS, based on the acceleration field to ensure Galilean invariance is proposed in this paper. The minima of the acceleration magnitude (a superset of acceleration zeros) are extracted and discriminated into vortices and saddle points, based on the spectral properties of the velocity Jacobian. The extraction of topological features is performed with purely combinatorial algorithms from discrete computational topology. The feature points are prioritized with persistence, as a physically meaningful importance mea sure. These feature points are tracked in time with a robust algorithm for tracking features. Thus, a space-time hierarchy of the minima is built and vortex merging events are detected. We apply the acceleration feature extraction strategy to three two-dimensional shear flows: (1) an incompressible periodic cylinder wake, (2) an incompressible planar mixing layer and (3) a weakly compressible planar jet. The vortex-like acceleration feature points are shown to be well aligned with acceleration zeros, maxima of the vorticity magnitude, minima of the pressure field and minima of lambda(2). Copyright (C) 2016 by IPPT PAN

  • 192.
    Paulsson, Victoria
    Linköping University, Department of Management and Engineering, Information Systems and Digitalization. Linköping University, Faculty of Arts and Sciences.
    Accounting Information Systems: Supporting Business Strategy2022In: The Routledge Handbook of Accounting Information Systems / [ed] Erik Strauss, Martin Quinn, Taylor & Francis, 2022, 2, p. 285-300Chapter in book (Refereed)
    Abstract [en]

    Arguments to invest in Accounting Information Systems (AIS) are multiple, but two key themes have emerged in the literature: the potential for cost saving from improved efficiency and the capacity to support business strategies. This chapter examines the latter of these two themes, taking as its starting point Porter’s two generic business strategies: cost leadership and differentiation. Two approaches to AIS acquisition are considered: bespoke development and off-the-shelf purchase. These two dimensions – generic business strategy and software acquisition mode – provide a framework for analysis of AIS support for firms and the four quadrants of the framework provide the basis for this chapter. A key contribution of the chapter is the identification of the critical factors involved in the choice of AIS to support the business strategy. The chapter also considers the implications for AIS of new forms of business competition afforded by platforms, networks and ecosystems and new modes of transferring and recording value through cryptocurrencies and blockchains.

  • 193.
    Eliasson, Jonas
    et al.
    Centre for Transport Studies, KTH Royal Institute of Technology, Stockholm, Sweden.
    Börjesson, Maria
    Centre for Transport Studies, KTH Royal Institute of Technology, Stockholm, Sweden.
    van Amelsfort, Dirk
    WSP Analysis & Strategy, Stockholm, Sweden.
    Brundell-Freij, Karin
    WSP Analysis & Strategy, Stockholm, Sweden.
    Engelson, Leonid
    Centre for Transport Studies, KTH Royal Institute of Technology, Stockholm, Sweden; WSP Analysis & Strategy, Stockholm, Sweden.
    Accuracy of congestion pricing forecasts2013In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 52, p. 34-46Article in journal (Refereed)
    Abstract [en]

    This paper compares forecast effects of the Stockholm congestion charges with actual outcomes. The most important concerns during the design of the congestion charging scheme were the traffic reduction in bottlenecks, the increase in public transport ridership, the decrease of vehicle kilometres in the city centre, and potential traffic effects on circumferential roads. Comparisons of forecasts and actual outcomes show that the transport model predicted all of these factors well enough to allow planners to draw correct conclusions regarding the design and preparations for the scheme. The one major shortcoming was that the static assignment network model was unable to predict the substantial reductions of queuing times. We conclude that the transport model worked well enough to be useful as decision support, performing considerably better than unaided "experts' judgments", but that results must be interpreted taking the model's limitations into account. The positive experiences from the Stockholm congestion charges hence seem to be transferable to other cities in the sense that if a charging system is forecast to have beneficial effects on congestion, then this is most likely true.

  • 194.
    Chu, Ming
    et al.
    Fudan Univ, Peoples R China.
    Liu, Shao-Bo
    Fudan Univ, Peoples R China.
    Yu, An-Ran
    Fudan Univ, Peoples R China.
    Yu, Hao-Miao
    Beijing Jiaotong Univ, Peoples R China.
    Qin, Jiajun
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Yi, Rui-Chen
    Fudan Univ, Peoples R China.
    Pei, Yuan
    Fudan Univ, Peoples R China.
    Zhu, Chun-Qin
    Fudan Univ, Peoples R China.
    Zhu, Guang-Rui
    Fudan Univ, Peoples R China.
    Zeng, Qi
    Shanghai Univ Engn Sci, Peoples R China.
    Hou, Xiao-Yuan
    Fudan Univ, Peoples R China.
    Accurate capacitance-voltage characterization of organic thin films with current injection*2021In: Chinese Physics B, ISSN 1674-1056, Vol. 30, no 8, article id 087301Article in journal (Refereed)
    Abstract [en]

    To deal with the invalidation of commonly employed series model and parallel model in capacitance-voltage (C-V) characterization of organic thin films when current injection is significant, a three-element equivalent circuit model is proposed. On this basis, the expression of real capacitance in consideration of current injection is theoretically derived by small-signal analysis method. The validity of the proposed equivalent circuit and theoretical expression are verified by a simulating circuit consisting of a capacitor, a diode, and a resistor. Moreover, the accurate C-V characteristic of an organic thin film device is obtained via theoretical correction of the experimental measuring result, and the real capacitance is 35.7% higher than the directly measured capacitance at 5-V bias in the parallel mode. This work strongly demonstrates the necessity to consider current injection in C-V measurement and provides a strategy for accurate C-V characterization experimentally.

  • 195.
    Bhat, Goutam
    Linköping University, Department of Electrical Engineering, Computer Vision.
    Accurate Tracking by Overlap Maximization2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Visual object tracking is one of the fundamental problems in computer vision, with a wide number of practical applications in e.g.\ robotics, surveillance etc. Given a video sequence and the target bounding box in the first frame, a tracker is required to find the target in all subsequent frames. It is a challenging problem due to the limited training data available. An object tracker is generally evaluated using two criterias, namely robustness and accuracy. Robustness refers to the ability of a tracker to track for long durations, without losing the target. Accuracy, on the other hand, denotes how accurately a tracker can estimate the target bounding box.

    Recent years have seen significant improvement in tracking robustness. However, the problem of accurate tracking has seen less attention. Most current state-of-the-art trackers resort to a naive multi-scale search strategy which has fundamental limitations. Thus, in this thesis, we aim to develop a general target estimation component which can be used to determine accurate bounding box for tracking. We will investigate how bounding box estimators used in object detection can be modified to be used for object tracking. The key difference between detection and tracking is that in object detection, the classes to which the objects belong are known. However, in tracking, no prior information is available about the tracked object, other than a single image provided in the first frame. We will thus investigate different architectures to utilize the first frame information to provide target specific bounding box predictions. We will also investigate how the bounding box predictors can be integrated into a state-of-the-art tracking method to obtain robust as well as accurate tracking.

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  • 196.
    Chen, Hu
    et al.
    King Abdullah Univ Sci & Technol KAUST, Saudi Arabia.
    Moser, Maximilian
    Imperial Coll London, England; Imperial Coll London, England; Univ Oxford, England.
    Wang, Suhao
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jellett, Cameron
    Imperial Coll London, England; Imperial Coll London, England.
    Thorley, Karl
    Univ Kentucky, KY 40506 USA.
    Harrison, George T.
    King Abdullah Univ Sci & Technol KAUST, Saudi Arabia.
    Jiao, Xuechen
    Monash Univ, Australia.
    Xiao, Mingfei
    Univ Cambridge, England.
    Purushothaman, Balaji
    King Abdullah Univ Sci & Technol KAUST, Saudi Arabia.
    Alsufyani, Maryam
    King Abdullah Univ Sci & Technol KAUST, Saudi Arabia.
    Bristow, Helen
    Imperial Coll London, England; Imperial Coll London, England; Univ Oxford, England.
    De Wolf, Stefaan
    King Abdullah Univ Sci & Technol KAUST, Saudi Arabia.
    Gasparini, Nicola
    Imperial Coll London, England; Imperial Coll London, England.
    Wadsworth, Andrew
    Imperial Coll London, England; Imperial Coll London, England; Univ Oxford, England.
    McNeill, Christopher R.
    Monash Univ, Australia.
    Sirringhaus, Henning
    Univ Cambridge, England.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    McCulloch, Iain
    King Abdullah Univ Sci & Technol KAUST, Saudi Arabia; Univ Oxford, England.
    Acene Ring Size Optimization in Fused Lactam Polymers Enabling High n-Type Organic Thermoelectric Performance2021In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 143, no 1, p. 260-268Article in journal (Refereed)
    Abstract [en]

    Three n-type fused lactam semiconducting polymers were synthesized for thermoelectric and transistor applications via a cheap, highly atom-efficient, and nontoxic transition-metal free aldol polycondensation. Energy level analysis of the three polymers demonstrated that reducing the central acene core size from two anthracenes (A-A), to mixed naphthalene-anthracene (A-N), and two naphthalene cores (N-N) resulted in progressively larger electron affinities, thereby suggesting an increasingly more favorable and efficient solution doping process when employing 4-(2,3-dihydro-1,3-dimethyl-1H-benzimidazol-2-yl)-N,N-dimethylbenzenamine (N-DMBI) as the dopant. Meanwhile, organic field effect transistor (OFET) mobility data showed the N-N and A-N polymers to feature the highest charge carrier mobilities, further highlighting the benefits of aryl core contraction to the electronic performance of the materials. Ultimately, the combination of these two factors resulted in N-N, A-N, and A-A to display power factors (PFs) of 3.2 mu W m(-1) K-2, 1.6 mu W m(-1 )K(-2), and 0.3 mu W m(-1) K-2, respectively, when doped with N-DMBI, whereby the PFs recorded for N-N and A-N are among the highest reported in the literature for n-type polymers. Importantly, the results reported in this study highlight that modulating the size of the central acene ring is a highly effective molecular design strategy to optimize the thermoelectric performance of conjugated polymers, thus also providing new insights into the molecular design guidelines for the next generation of high-performance n-type materials for thermoelectric applications.

  • 197.
    Lundell, Fredrik
    et al.
    Linköping University, Department of Management and Engineering.
    Roxlin, Victor
    Linköping University, Department of Management and Engineering.
    Achieving a strategically aligned project portfolio: A case study on the Project Portfolio Management activities of selecting projects and allocating resources in a matrix organisation2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Project portfolio management (PPM) is considered a central part for achieving intended strategies for organisations. However, only a percentage of strategies are actually realised, and whilst much previous research has focused on the formulation of strategies, less has been directed towards the realisation. To gain further understanding of how PPM can contribute to realising strategies, this thesis studied the PPM activities of selecting projects and allocating resources, and related challenges when trying to achieve a strategically aligned project portfolio in a matrix organisation. A qualitative case study was performed at a pharmaceutical production company in Stockholm referred to as Medex. An abductive research approach was used, and the data was thematically analysed whilst striving to achieve triangulation. The study was divided into a pre-study and a main study consisting of a total of 15 semi-structured interviews with participants at different positions within the organisation, in parallel to the collection of secondary data from Medex’s intranet. 

     

    The study indicate that it is a challenge for a matrix organisation to align projects to strategy through project objectives, and that it is rather project values’ strong connection to strategy that provide a clear link between projects and strategy. It further suggests that using project value for linking projects to strategy can increase the understanding of the motivation of project priorities, as well as creating a foundation for determining if the allocation of resources is oriented towards strategy. Furthermore, the study demonstrates the challenge and necessity for top management to base their decisions on sufficient and reliable information. Moreover, the selection of projects must be performed in accordance with available resource capacity, which highlights the need for strong connections between short-, medium- and long-term resource allocation. Furthermore, the study emphasises the need for a structured way of evaluating PPM processes to improve and address associated challenges. Additionally, the high competition between resources in a matrix organisation is depicted and the study indicates that a strong focus on profits can limit the possibility of achieving a strategically aligned project portfolio. While the study is based on a single case, the findings can be regarded as transferable, at varying extents, to other companies of similar size and organisational structure as well.

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  • 198.
    Persson, Jakob
    Linköping University, Department of Computer and Information Science.
    Achieving business impact with IT: A qualitative study of the practice and theory of driving change with technology, interaction and service design2017Independent thesis Basic level (degree of Bachelor), 12 credits / 18 HE creditsStudent thesis
    Abstract [en]

    As our society becomes more and more digitalized, IT projects play an increasingly important role. The relatively high failure rates in IT projects have spurred the development of methods and models to improve success rate by managing for outcomes rather than constraints.

    This thesis aims to contribute to our understanding of how outcome-based project methods are used in practice, and how they’re understood and conceptualized by their users such as project managers, product managers and interaction designers. It provides an overview of seven methods for managing projects for outcomes and presents findings regarding how users of a subset of these methods apply and reason about them.

    The study’s findings include the identification of six themes regarding the application and use of these methods and four concepts describing how they’re understood. The results indicate that the methods studied have a wide-reaching influence over workplace collaboration and culture, and provide generic strategies for solving problems in the domains of software development, interaction design and service design.

    Further research is recommended to determine how these methods can be used and improved to further enhance collaboration, communication, and motivation in the workplace and the methods’ wider influence on IT project success. 

    Download full text (pdf)
    fulltext
  • 199.
    Tong, Danqing
    et al.
    Donghua Univ, Peoples R China.
    Siddique, Farhan
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Bahauddin Zakariya Univ, Pakistan.
    Qian, Cheng
    Donghua Univ, Peoples R China.
    Baryshnikov, Glib
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wu, Hongwei
    Donghua Univ, Peoples R China.
    Achieving short-wavelength free radical emission by combining small conjugated structure and anti-Kasha emission2023In: Dyes and pigments, ISSN 0143-7208, E-ISSN 1873-3743, Vol. 219, article id 111625Article in journal (Refereed)
    Abstract [en]

    Since the natural narrow bandgaps of free radicals usually lead to emission in the long-wavelength region, it is still of great challenge to design radical luminescent materials with stable and short-wavelength emission in the ambient environment. In this work, a series of dicarbonyl-substituted organic molecules with small conjugated structures were used to form free radicals with short-wavelength radical emission. These low-conjugated mol-ecules with only one benzene ring showed stable photoinduced free radical emission after doping with poly-methyl methacrylate (PMMA) because the rigid polymer environment could help stabilize the free radicals and limit the non-radiative energy transfer. Moreover, PMMA with electron-withdrawing groups could promote the generation of carbonyl radical cations. The theoretical calculation suggests that the free radical with anti-Kasha emission derived from high energy excited state (D4 or D5) would directly relax to the ground state, combining with the small spin delocalization of the low conjugation free radical, leading to short-wavelength emission. More importantly, such free radical emissions could also respond to external stimulation such as light irradiation or heat treatment. These materials show great potential in lithography information recording and information encryption. This design strategy provides new insights into molecular and functional diversity of free radical materials.

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  • 200.
    Kwiecinski, J
    et al.
    Sahlgrenska Academy.
    Josefsson, E
    Sahlgrenska Academy.
    Mitchell, J
    Trinity College, Dublin.
    Higgins, J
    Trinity College, Dublin.
    Magnusson, Mattias
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences.
    Foster, T
    Trinity College, Dublin.
    Jin, T
    Sahlgrenska Academy.
    Bokarewa, M
    Sahlgrenska Academy.
    Activation of Plasminogen by Staphylokinase Reduces the Severity of Staphylococcus aureusSystemic Systemic Infection2010In: Journal of Infectious Diseases, ISSN 0022-1899, E-ISSN 1537-6613, Vol. 202, no 7, p. 1041-1049Article in journal (Refereed)
    Abstract [en]

     

    Background. Theoretical and experimental data support the geographic differentiation strategy as a valuable tool for detecting loci under selection. In the context of Plasmodium falciparum malaria, few populations have been studied, with limited genomic coverage.

    Methods. Wild-type S. aureus strain LS-1, which lacks the ability to produce SAK, was modified by an insertion of the sak gene into its chromosome. The sak gene was integrated in 2 forms—(1) linked to its own promoter and (2) fused to the promoter of the protein A gene—which resulted in the overexpression of SAK. SAK is highly specific for human plg and exhibits almost no activity toward murine plg. To investigate the role played by SAK in a murine infection model, human plg transgenic mice and their wild-type counterparts were inoculated intravenously with congenic S. aureus strains differing in SAK production.

    Results. Human plg transgenic mice inoculated with SAK-expressing strains displayed significantly reduced mortality, less weight loss, and lower bacterial loads in kidneys than did the wild-type mice. No difference in the severity of sepsis was observed between transgenic and wild-type mice infected with a SAK-deficient strain.

    Conclusions. The results suggest that expression of SAK followed by activation of plg alleviates the course of S. aureus sepsis. 

     

     

     

     

     

     

     

     

     

      

     

     

     

     

     

     

     

     

     

     

     

     

     

    Background.

     

    Staphylokinase (SAK) is produced by the majority of Staphylococcus aureus strains. It is an extracellular protein that activates the conversion of human plasminogen (plg) to plasmin. The role played by SAK in staphylococcal infection is unclear.Methods. Wild-type S. aureus strain LS-1, which lacks the ability to produce SAK, was modified by an insertion of the sak gene into its chromosome. The sak gene was integrated in 2 forms—(1) linked to its own promoter and (2) fused to the promoter of the protein A gene—which resulted in the overexpression of SAK. SAK is highly specific for human plg and exhibits almost no activity toward murine plg. To investigate the role played by SAK in a murine infection model, human plg transgenic mice and their wild-type counterparts were inoculated intravenously with congenic S. aureus strains differing in SAK production.Results. Human plg transgenic mice inoculated with SAK-expressing strains displayed significantly reduced mortality, less weight loss, and lower bacterial loads in kidneys than did the wild-type mice. No difference in the severity of sepsis was observed between transgenic and wild-type mice infected with a SAK-deficient strain.Conclusions. The results suggest that expression of SAK followed by activation of plg alleviates the course of S. aureus

    sepsis.

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