liu.seSearch for publications in DiVA
Change search
Refine search result
1234567 51 - 100 of 20165
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 51.
    Abidin, Aysajan
    et al.
    Linköping University, Department of Mathematics, Applied Mathematics. Linköping University, The Institute of Technology.
    Larsson, Jan-Åke
    Linköping University, Department of Mathematics, Applied Mathematics. Linköping University, The Institute of Technology.
    Special Properties of Strongly Universal2 Hash Functions Important in Quantum Cryptography2009In: AIP Conference Proceedings, ISSN 0094-243X, Foundations of Probability and Physics—5, Växjö, augusti 2008, New York: American Institute of Physics , 2009, Vol. 1101, p. 289-293Conference paper (Refereed)
    Abstract [en]

    Secure message authentication is an important part of Quantum Key Distribution. In this paper we analyze special properties of a Strongly Universal2 hash function family, an understanding of which is important in the security analysis of the authentication used in Quantum Cryptography. We answer the following question: How much of Alices message does Eve need to influence so that the message along with its tag will give her enough information to create the correct tag for her message?

  • 52.
    Abidin, Aysajan
    et al.
    Linköping University, Department of Mathematics, Applied Mathematics. Linköping University, The Institute of Technology.
    Larsson, Jan-Åke
    Linköping University, Department of Mathematics, Applied Mathematics. Linköping University, The Institute of Technology.
    Vulnerability of "A Novel Protocol-Authentication Algorithm Ruling out a Man-in-the-Middle Attack in Quantum Cryptography"2009In: International Journal of Quantum Information, ISSN 0219-7499, Vol. 7, no 5, p. 1047-1052Article in journal (Refereed)
    Abstract [en]

    In this paper, we review and comment on "A novel protocol-authentication algorithm ruling out a man-in-the-middle attack in quantum cryptography" [M. Peev et al., Int. J. Quant. Inf. 3 (2005) 225]. In particular, we point out that the proposed primitive is not secure when used in a generic protocol, and needs additional authenticating properties of the surrounding quantum-cryptographic protocol.

  • 53.
    Abidin, Aysajan
    et al.
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, The Institute of Technology.
    Pacher, Christoph
    Austrian Institute of Technology, Austria.
    Lorünser, Thomas
    Austrian Institute of Technology, Austria.
    Larsson, Jan-Åke
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, The Institute of Technology.
    Peev, Momtchil
    Austrian Institute of Technology, Austria.
    Quantum cryptography and authentication with low key-consumption2011In: Proceedings of SPIE - The International Society for Optical Engineering, 2011, p. 818916-Conference paper (Refereed)
    Abstract [en]

    Quantum Key Distribution (QKD - also referred to as Quantum Cryptography) is a technique for secret key agreement. It has been shown that QKD rigged with Information-Theoretic Secure (ITS) authentication (using secret key) of the classical messages transmitted during the key distribution protocol is also ITS. Note, QKD without any authentication can trivially be broken by man-in-the-middle attacks. Here, we study an authentication method that was originally proposed because of its low key consumption; a two-step authentication that uses a publicly known hash function, followed by a secret strongly universal2 hash function, which is exchanged each round. This two-step authentication is not information-theoretically secure but it was argued that nevertheless it does not compromise the security of QKD. In the current contribution we study intrinsic weaknesses of this approach under the common assumption that the QKD adversary has access to unlimited resources including quantum memories. We consider one implementation of Quantum Cryptographic protocols that use such authentication and demonstrate an attack that fully extract the secret key. Even including the final key from the protocol in the authentication does not rule out the possibility of these attacks. To rectify the situation, we propose a countermeasure that, while not informationtheoretically secure, restores the need for very large computing power for the attack to work. Finally, we specify conditions that must be satisfied by the two-step authentication in order to restore informationtheoretic security.

  • 54.
    Abongo, D. A.
    et al.
    University of Nairobi, Kenya.
    Wandiga, S. O.
    University of Nairobi, Kenya.
    Jumba, I. O.
    University of Nairobi, Kenya.
    Van den Brink, P. J.
    University of Wageningen and Research Centre, Netherlands.
    Naziriwo, B. B.
    Makerere University, Uganda.
    Madadi, V. O.
    University of Nairobi, Kenya.
    Wafula, G. A.
    University of Nairobi, Kenya.
    Nkedi-Kizza, P.
    University of Florida, FL USA.
    Kylin, Henrik
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. North West University, South Africa.
    Occurrence, abundance and distribution of benthic macroinvertebrates in the Nyando River catchment, Kenya2015In: African Journal of Aquatic Science, ISSN 1608-5914, E-ISSN 1727-9364, Vol. 40, no 4, p. 373-392Article in journal (Refereed)
    Abstract [en]

    A baseline study was conducted of the occurrence of macroinvertebrates at 26 sites in the Nyando River catchment in 2005-2006. A total of 13 orders and 16 families of Arthropoda, Mollusca, Platyhelminthes and Annelida were collected, with the order Ephemeroptera being most abundant in the up- and mid-stream reaches, followed by Hemiptera and Plecoptera respectively. The downstream sections of the river were dominated by Hirudinea and tubificids, as the water quality deteriorated mainly due to local land use, raw sewage effluent discharge and annual floods. Insects and annelids were the main invertebrates found and the extent of pollution increased from mid-section (Site 15) downwards as the river flowed into the Winam Gulf. Stringent management measures are required to safeguard the environment and ecosystems of Lake Victoria.

  • 55.
    Abong'o, Deborah
    et al.
    University of Nairobi, Kenya.
    Wandiga, Shem
    University of Nairobi, Kenya.
    Jumba, Isaac
    University of Nairobi, Kenya.
    Madadi, Vincent
    University of Nairobi, Kenya.
    Kylin, Henrik
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Impacts of pesticides on human health and environment in the River Nyando catchment, Kenya2014In: International Journal of Humanities, Arts, Medicine and Sciences, ISSN 2348-0521, Vol. 2, no 3, p. 1-14Article in journal (Other academic)
    Abstract [en]

    The population of the River Nyando catchment largely relies on rain fed agriculture for their subsistence.

    Important crops grown include cereals, cash crops fruits and vegetables. Farming is one of the contributors of pollution to Lake Victoria. Organophosphates and other banned organochlorine pesticides such as lindane, aldrin and dieldrin were used by farmers. The pesticides transport was by storm water run-off and air drift into the lake. Environmental risk assessment background information was collected through questionnaire and interviews of farmers to determine knowledge and safe use of pesticides. Fourteen pesticides were identified as commonly used of which four are toxic to bees and five to birds. The farmers identified declines in the number of pollinating insects, the disappearance of Red-billed Oxpecker (Buphagus erythrorthynchus) and wild bird’s fatalities. The general knowledge among farmers about chemicals risks, safety, and chronic illnesses was low. Activities that increases environmental awareness and safety of pesticides should be initiated by the agrochemical firms and government.

  • 56.
    Abong'o, Deborah
    et al.
    University of Nairobi, Kenya.
    Wandiga, Shem
    University of Nairobi. Kenya.
    Jumba, Isac
    University of Nairobi, Kenya.
    van den Brink, Paul
    Wageningen University, the Netherlands.
    Nazariwo, Betty
    Makerere University, Uganda.
    Madadi, Vincent
    University of Nairobi, Kenya.
    Wafula, Godfrey
    University of Nairobi, Kenya.
    Kylin, Henrik
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nkedi-Kizza, Peter
    University of Florida, USA.
    Organochlorine pesticide residue levels in soil from the Nyando River catchment, Kenya2015In: Africa Journal of Physical Sciences, ISSN 2313-3317, Vol. 2, no 1, p. 18-32Article in journal (Refereed)
    Abstract [en]

    Soil samples were collected from six locations representative of the Nyando River catchment area of the Lake Victoria over a period of two years. Sampling was done four times in the year in February, May, September and December 2005 and 2006 in farms where maize, tea, sugar cane, coffee, rice and vegetables have been grown over the years. This coincided with the effects of different seasons and farming activities on residue levels of the pesticides in use. The objective was to investigate levels and distribution of organochlorine pesticides that have either been banned or are restricted for use in Kenya. Organochlorine pesticides investigated were DDT, lindane, aldrin, dieldrin, heptachlor, endrin, endosulfan (both α- and β- isomers and endosulfan sulphate), the sum is called “total” or Σendosulfan and methoxychlor. Prior to the ban or restriction in use, these pesticides had found wide applications in public health for control of disease vectors and in agriculture for control of crop pests. The analysis revealed presence of all the targeted pesticides with the highest mean concentrations for methoxychlor 140 ± 1.5 μg/kg, Σendosulfan (30 ± 2.1 μg/kg), aldrin (18 ± 0.28 μg/kg), respectively. The results show the presence of these pesticides in soils in the basin and this could be impacting negatively on the ecosystem health of the area.

  • 57.
    Abraham-Nordling, Mirna
    et al.
    Karolinska institutet.
    Persson, Bengt
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, The Institute of Technology.
    Nordling, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, The Institute of Technology.
    Model of the complex of Parathyroid hormone-2receptor and Tuberoinfundibular peptide of39 residues2010In: BMC Reseach Notes, ISSN 1756-0500, Vol. 3, no 270Article in journal (Refereed)
    Abstract [en]

    Background

    We aim to propose interactions between the parathyroid hormone-2 receptor (PTH2R) and its ligand the tuberoinfundibular peptide of 39 residues (TIP39) by constructing a homology model of their complex. The two related peptides parathyroid hormone (PTH) and parathyroid hormone related protein (PTHrP) are compared with the complex to examine their interactions.

    Findings

    In the model, the hydrophobic N-terminus of TIP39 is buried in a hydrophobic part of the central cavity between helices 3 and 7. Comparison of the peptide sequences indicates that the main discriminator between the agonistic peptides TIP39 and PTH and the inactive PTHrP is a tryptophan-phenylalanine replacement. The model indicates that the smaller phenylalanine in PTHrP does not completely occupy the binding site of the larger tryptophan residue in the other peptides. As only TIP39 causes internalisation of the receptor and the primary difference being an aspartic acid in position 7 of TIP39 that interacts with histidine 396 in the receptor, versus isoleucine/histidine residues in the related hormones, this might be a trigger interaction for the events that cause internalisation.

    Conclusions

    A model is constructed for the complex and a trigger interaction for full agonistic activation between aspartic acid 7 of TIP39 and histidine 396 in the receptor is proposed.

  • 58.
    Abrahamsson, Björn
    Linköping University, Department of Electrical Engineering.
    Architectures for Multiplication in Galois Rings2004Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    This thesis investigates architectures for multiplying elements in Galois rings of the size 4^m, where m is an integer.

    The main question is whether known architectures for multiplying in Galois fields can be used for Galois rings also, with small modifications, and the answer to that question is that they can.

    Different representations for elements in Galois rings are also explored, and the performance of multipliers for the different representations is investigated.

  • 59.
    Abrahamsson, David
    Linköping University, Department of Computer and Information Science.
    Security Enhanced Firmware Update Procedures in Embedded Systems2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Many embedded systems are complex, and it is often required that the firmware in these systems are updatable by the end-user. For economical and confidentiality reasons, it is important that these systems only accept firmware approved by the firmware producer.

    This thesis work focuses on creating a security enhanced firmware update procedure that is suitable for use in embedded systems. The common elements of embedded systems are described and various candidate algorithms are compared as candidates for firmware verification. Patents are used as a base for the proposal of a security enhanced update procedure. We also use attack trees to perform a threat analysis on an update procedure.

    The results are a threat analysis of a home office router and the proposal of an update procedure. The update procedure will only accept approved firmware and prevents reversion to old, vulnerable, firmware versions. The firmware verification is performed using the hash function SHA-224 and the digital signature algorithm RSA with a key length of 2048. The selection of algorithms and key lengths mitigates the threat of brute-force and cryptanalysis attacks on the verification algorithms and is believed to be secure through 2030.

  • 60.
    Abrahamsson, Lars
    Linköping University, Department of Electrical Engineering.
    A portal based system for indoor environs2006Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    The purpose of this thesis is to document the development of the graphics part of an extremely pluggable game engine/lab environment for a course in advanced game programming. This thesis is one out of five, and concerns indoor, realtime computer 3D graphics. It covers state-of-the-art techniques such as GLSL - the OpenGL Shading Language - and more well known techniques such as portal based rendering.

  • 61.
    Abrahamsson, Linn
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Melin Wenström, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Användning av prototyper som verktyg för kravhantering i agil mjukvaruutveckling: - En fallstudie2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Requirements Engineering (RE) in Agile Software Development (ASD) is a challenge thatmany face and several techniques exist when doing so. One such technique is prototyping, when a model of a product is used to gather important information in software develop-ment. To describe how much a prototype resembles the product the notion of fidelity is used. The aim of this study is to contribute to research regarding prototyping in ASD,and to examine the effect of a prototype’s fidelity when using prototypes in discussionsduring RE. A case study is performed at the company Exsitec where staff are interviewedregarding prototyping in software development. Thereafter, two prototypes of low andhigh fidelity are developed and used in interviews as a basis for discussion. Based on thisstudy, the use of prototypes in software projects can help customers trust the process,improve communication with customers, and facilitate when trying to reach consensusamong different stakeholders. Furthermore, depending on how they are used, prototypescan contribute to understanding the big picture of the requirements and can also serve asdocumentation. The study also shows some, albeit subtle, differences in the informationcollected using prototypes with low and high fidelity. The use of a high fidelity prototypeseems to generate more requirements, but makes interviewees less likely to come up withlarger, more comprehensive requirement changes.

  • 62.
    Abrahamsson, Marcus
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    A platform for third-party applications on the web2013Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    A trend seen on the web today is to create a platform where externally developed applications can run inside some kind of main application. This is often done by providing an API to access data and business logic of your service and a sandbox environment in which third-party applications can run. By providing this, it is made possible for external developers to come up with new ideas based on your service. Some good examples on this are Spotify Apps, Apps on Facebook and SalesForce.com.

    Ipendo Systems AB is a company that develops a web platform for intellectual properties. Currently most things on this platform are developed by developers at Ipendo Systems AB. Some interest has though risen to enable external developers to create applications that will in some way run inside the main platform.

    In this thesis an analysis of already existing solutions has been done. These solutions were Spotify Apps and Apps on Facebook. The two have different approaches on how to enable third-party applications to run inside their own service. Facebook’s solution builds mainly on iframe embedded web pages where data access is provided through a web API. Spotify on the other hand hosts the third-party applications themselves but the applications may only consist of HTML5, CSS3 and JavaScript.

    In addition to the analysis a prototype was developed. The purpose of the prototype was to show possible ways to enable third-party applications to run inside your own service. Two solutions showing this were developed. The first one was based on Facebook’s approach with iframing of external web pages. The second was a slightly modified version of Spotify’s solution with only client-side code hosted by the main application. To safely embed the client side code in the main application a sandboxing tool for JavaScript called Caja was used.

    Of the two versions implemented in the prototype was the Iframe solution considered more ready to be utilized in a production environment than Caja. Caja could be seen as an interesting technique for the future but might not be ready to use today. The reason behind this conclusion was that Caja decreased the performance of the written JavaScript as well as adding complexity while developing the third-party applications.

  • 63.
    Abrahamsson, Olle
    Linköping University, Department of Mathematics, Mathematics and Applied Mathematics. Linköping University, Faculty of Science & Engineering.
    A Gröbner basis algorithm for fast encoding of Reed-Müller codes2016Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    In this thesis the relationship between Gröbner bases and algebraic coding theory is investigated, and especially applications towards linear codes, with Reed-Müller codes as an illustrative example. We prove that each linear code can be described as a binomial ideal of a polynomial ring, and that a systematic encoding algorithm for such codes is given by the remainder of the information word computed with respect to the reduced Gröbner basis. Finally we show how to apply the representation of a code by its corresponding polynomial ring ideal to construct a class of codes containing the so called primitive Reed-Müller codes, with a few examples of this result.

  • 64.
    Abrahamsson, Olle
    Linköping University, Department of Electrical Engineering, Communication Systems.
    Hide and Seek in a Social Network2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis a known heuristic for decreasing a node's centrality scores while maintaining influence, called ROAM, is compared to a modified version specifically designed to decrease eigenvector centrality. The performances of these heuristics are also tested against the Shapley values of a cooperative game played over the considered network, where the game is such that influential nodes receive higher Shapley values. The modified heuristic performed at least as good as the original ROAM, and in some instances even better (especially when the terrorist network behind the World Trade Center attacks was considered). Both heuristics increased the influence score for a given targeted node when applied consecutively on the WTC network, and consequently the Shapley values increased as well. Therefore the Shapley value of the game considered in this thesis seems to be well suited for discovering individuals that are assumed to actively trying to evade social network analysis.

  • 65.
    Abrahamsson, Peder
    Linköping University, Department of Computer and Information Science.
    Mer lättläst: Påbyggnad av ett automatiskt omskrivningsverktyg till lätt svenska2011Independent thesis Basic level (degree of Bachelor), 12 credits / 18 HE creditsStudent thesis
    Abstract [sv]

    Det svenska språket ska finnas tillgängligt för alla som bor och verkar i Sverige. Därförär det viktigt att det finns lättlästa alternativ för dem som har svårighet att läsa svensktext. Detta arbete bygger vidare på att visa att det är möjligt att skapa ett automatisktomskrivningsprogram som gör texter mer lättlästa. Till grund för arbetet liggerCogFLUX som är ett verktyg för automatisk omskrivning till lätt svenska. CogFLUXinnehåller funktioner för att syntaktiskt skriva om texter till mer lättläst svenska.Omskrivningarna görs med hjälp av omskrivningsregler framtagna i ett tidigare projekt.I detta arbete implementeras ytterligare omskrivningsregler och även en ny modul förhantering av synonymer. Med dessa nya regler och modulen ska arbetet undersöka omdet är det är möjligt att skapa system som ger en mer lättläst text enligt etableradeläsbarhetsmått som LIX, OVIX och Nominalkvot. Omskrivningsreglerna ochsynonymhanteraren testas på tre olika texter med en total lägnd på ungefär hundra tusenord. Arbetet visar att det går att sänka både LIX-värdet och Nominalkvoten signifikantmed hjälp av omskrivningsregler och synonymhanterare. Arbetet visar även att det finnsfler saker kvar att göra för att framställa ett riktigt bra program för automatiskomskrivning till lätt svenska.

  • 66.
    Abrahamsson, Robin
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Berntsen, David
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Comparing modifiability of React Native and two native codebases2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Creating native mobile application on multiple platforms generate a lot of duplicate code. This thesis has evaluated if the code quality attribute modifiability improves when migrating to React Native. One Android and one iOS codebase existed for an application and a third codebase was developed with React Native. The measurements of the codebases were based on the SQMMA-model. The metrics for the model were collected with static analyzers created specifically for this project. The results created consists of graphs that show the modifiability for some specific components over time and graphs that show the stability of the platforms. These graphs show that when measuring code metrics on applications over time it is better to do this on a large codebase that has been developed for some time. When calculating a modifiability value the sum of the metrics and the average value of the metrics between files should be used and it is shown that the React Native platform seems to be more stable than native.

  • 67.
    Abrahamsson, S.
    et al.
    SLU, Umeå, Sweden .
    Ahlinder, J.
    FOI, Umeå, Sweden .
    Waldmann, Patrik
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, The Institute of Technology.
    García-Gil, M. R.
    SLU, Umeå, Sweden .
    Maternal heterozygosity and progeny fitness association in an inbred Scots pine population2013In: Genetica, ISSN 0016-6707, E-ISSN 1573-6857, Vol. 141, no 1-3, p. 41-50Article in journal (Refereed)
    Abstract [en]

    Associations between heterozygosity and fitness traits have typically been investigated in populations characterized by low levels of inbreeding. We investigated the associations between standardized multilocus heterozygosity (stMLH) in mother trees (obtained from12 nuclear microsatellite markers) and five fitness traits measured in progenies from an inbred Scots pine population. The traits studied were proportion of sound seed, mean seed weight, germination rate, mean family height of one-year old seedlings under greenhouse conditions (GH) and mean family height of three-year old seedlings under field conditions (FH). The relatively high average inbreeding coefficient (F) in the population under study corresponds to a mixture of trees with different levels of co-ancestry, potentially resulting from a recent bottleneck. We used both frequentist and Bayesian methods of polynomial regression to investigate the presence of linear and non-linear relations between stMLH and each of the fitness traits. No significant associations were found for any of the traits except for GH, which displayed negative linear effect with stMLH. Negative HFC for GH could potentially be explained by the effect of heterosis caused by mating of two inbred mother trees (Lippman and Zamir 2006), or outbreeding depression at the most heterozygote trees and its negative impact on the fitness of the progeny, while their simultaneous action is also possible (Lynch. 1991). However,since this effect wasn’t detected for FH, we cannot either rule out that the greenhouse conditions introduce artificial effects that disappear under more realistic field conditions.

  • 68.
    Abrahamsson, Tobias
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Poxson, David
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gabrielsson, Erik
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Sandberg, Mats
    RISE Acreo AB, Sweden.
    Simon, Daniel T
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol2019In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, article id 484Article in journal (Refereed)
    Abstract [en]

    In the emerging field of organic bioelectronics, conducting polymers and ion-selective membranes are combined to form resistors, diodes, transistors, and circuits that transport and process both electronic and ionic signals. Such bioelectronics concepts have been explored in delivery devices that translate electronic addressing signals into the transport and dispensing of small charged biomolecules at high specificity and spatiotemporal resolution. Manufacturing such "iontronic" devices generally involves classical thin film processing of polyelectrolyte layers and insulators followed by application of electrolytes. This approach makes miniaturization and integration difficult, simply because the ion selective polyelectrolytes swell after completing the manufacturing. To advance such bioelectronics/iontronics and to enable applications where relatively larger molecules can be delivered, it is important to develop a versatile material system in which the charge/size selectivity can be easily tailormade at the same time enabling easy manufacturing of complex and miniaturized structures. Here, we report a one-pot synthesis approach with minimal amount of organic solvent to achieve cationic hyperbranched polyglycerol films for iontronics applications. The hyperbranched structure allows for tunable pre multi-functionalization, which combines available unsaturated groups used in crosslinking along with ionic groups for electrolytic properties, to achieve a one-step process when applied in devices for monolithic membrane gel formation with selective electrophoretic transport of molecules.

  • 69.
    Abramavicius, V.
    et al.
    Vilnius University, Lithuania; Centre Phys Science and Technology, Lithuania.
    Pranculis, V.
    Centre Phys Science and Technology, Lithuania.
    Melianas, Armantas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gulbinas, V.
    Centre Phys Science and Technology, Lithuania.
    Abramavicius, D.
    Vilnius University, Lithuania.
    Role of coherence and delocalization in photo-induced electron transfer at organic interfaces2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, no 32914Article in journal (Refereed)
    Abstract [en]

    Photo-induced charge transfer at molecular heterojunctions has gained particular interest due to the development of organic solar cells (OSC) based on blends of electron donating and accepting materials. While charge transfer between donor and acceptor molecules can be described by Marcus theory, additional carrier delocalization and coherent propagation might play the dominant role. Here, we describe ultrafast charge separation at the interface of a conjugated polymer and an aggregate of the fullerene derivative PCBM using the stochastic Schrodinger equation (SSE) and reveal the complex time evolution of electron transfer, mediated by electronic coherence and delocalization. By fitting the model to ultrafast charge separation experiments, we estimate the extent of electron delocalization and establish the transition from coherent electron propagation to incoherent hopping. Our results indicate that even a relatively weak coupling between PCBM molecules is sufficient to facilitate electron delocalization and efficient charge separation at organic interfaces.

  • 70.
    Abramian, David
    et al.
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Eklund, Anders
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Department of Computer and Information Science, The Division of Statistics and Machine Learning. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    REFACING: RECONSTRUCTING ANONYMIZED FACIAL FEATURES USING GANS2019In: 2019 IEEE 16TH INTERNATIONAL SYMPOSIUM ON BIOMEDICAL IMAGING (ISBI 2019), IEEE , 2019, p. 1104-1108Conference paper (Refereed)
    Abstract [en]

    Anonymization of medical images is necessary for protecting the identity of the test subjects, and is therefore an essential step in data sharing. However, recent developments in deep learning may raise the bar on the amount of distortion that needs to be applied to guarantee anonymity. To test such possibilities, we have applied the novel CycleGAN unsupervised image-to-image translation framework on sagittal slices of T1 MR images, in order to reconstruct, facial features from anonymized data. We applied the CycleGAN framework on both face-blurred and face-removed images. Our results show that face blurring may not provide adequate protection against malicious attempts at identifying the subjects, while face removal provides more robust anonymization, but is still partially reversible.

  • 71.
    Abramsson, Mia
    et al.
    Swedish Energy Agency, Sweden.
    Jidesjö, Anders
    Swedish Energy Agency, Sweden.
    Research and development projects aiming to increase young adults’ knowledge of energy and energy efficiency2015In: eceee Summer Study proceedings / [ed] Therese Laitinen Lindström, Borg & Co, Stockholm, Sweden, European Council for an Energy Efficient Economy (ECEEE), 2015, p. 509-514Conference paper (Refereed)
    Abstract [en]

    Children and young adults are important target groups in order to decrease the climate change effects and increase an energy-efficient end use. With increased knowledge and awareness these target groups could play a constructive role in the current and future transition of the energy system. The correlation between knowledge, awareness and behavioral change is central for improved energy efficiency in the society. Children and young adults and their interest in the natural and technical science are central to ensure the long-term capability needed to transform the energy system.

    To support this development the Swedish Energy Agency started with young adults as a target group in research and development projects in 2008. Since then approximately 5 million EUR has been allocated for projects aiming to increase knowledge in these areas among young adults by developing practical methods and tools, educational material or in-service training for teachers. Around thirty projects have been supported and three of them, KNUT school development project, KNUT evaluation research project and The Energy Fall, will be discussed in this paper.

     

    The KNUT school development project is a national school project aiming at increasing students’ knowledge and interest in energy and energy efficiency. KNUT also stimulates learning and career choices related to energy, climate and resources and therefor strengthen Sweden's capacities and competitiveness future in these areas. To ensure the scientific base a research group from Linköping University (KNUT evaluation research project) has followed the project’s activities. Best practices of methods and tools have been tested and disseminated within the project at both regional and national level.

     

    The KNUT evaluation research project has identified and analyzed five success factors regarding energy, climate change and energy efficiency of importance for education: 

    • The relationships between the national, regional and local level

    • The function of education vary in time due to the development of society

    • Get to know the education content inside and outside of school

    • Successful meetings between different actors

    • The educational systems capacity to educate all and at the same time recruit some for specialization

    This paper will present an overview of the Swedish Energy Agency’s work on research and development projects aiming to increase young adults’ knowledge of energy and energy efficiency and the KNUT evaluation research project results, analysis and success factors.

  • 72.
    Abrandt Dahlgren, Madeleine
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Nordenström, Elin
    University of Gothenburg, Gothenburg, Sweden.
    Rooney, Donna
    University of TechnologySydneyAustralia.
    Rystedt, Hans
    University of Gothenburg, Gothenburg, Sweden.
    Video as a Tool for Researching Simulation Practices2019In: Video as a Tool for Researching Simulation Practices: Materiality, Embodiment, Interaction / [ed] Madeleine Abrandt Dahlgren, Hans Rystedt, Li Felländer-Tsai and Sofia Nyström, Cham: Springer Publishing Company, 2019, p. 31-55Chapter in book (Refereed)
    Abstract [en]

    This chapter provides examples of how arrangements for collection and analyses of video data were organized across different sites. The common approach to data collection builds on established methods for recording of audiovisual materials in the social sciences with a focus on interaction and learning. The chapter describes how arrangements for data collection across different sites were organised, and how video analysis can be used as a method for collaborative analysis of practices. One approach is entitled purposeful approach to collaborative data analysis. A second approach draws on video-based studies of situated action, and a third approach of analysis is the use of qualitatively different readings of the same data. One does not replace the other, but rather draws out different features.

  • 73.
    Abreu, Fernanda
    et al.
    Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
    Leão, Pedro
    Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
    Vargas, Gabriele
    Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
    Cypriano, Jefferson
    Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
    Figueiredo, Viviane
    Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
    Enrich Prast, Alex
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
    Bazylinski, Dennis A.
    University of Nevada at Las Vegas, Las Vegas, NV, USA.
    Lins, Ulysses
    Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
    Culture-independent characterization of a novel magnetotactic member affiliated to the Beta class of the Proteobacteria phylum from an acidic lagoon2018In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 20, no 7, p. 2615-2624Article in journal (Refereed)
    Abstract [en]

    Summary Magnetotactic bacteria (MTB) comprise a group of motile microorganisms common in most mesothermal aquatic habitats with pH values around neutrality. However, during the last two decades, a number of MTB from extreme environments have been characterized including: cultured alkaliphilic strains belonging to the Deltaproteobacteria class of the Proteobacteria phylum; uncultured moderately thermophilic strains belonging to the Nitrospirae phylum; cultured and uncultured moderately halophilic or strongly halotolerant bacteria affiliated with the Deltaproteobacteria and Gammaproteobacteria classes and an uncultured psychrophilic species belonging to the Alphaproteobacteria class. Here, we used culture-independent techniques to characterize MTB from an acidic freshwater lagoon in Brazil (pH ? 4.4). MTB morphotypes found in this acidic lagoon included cocci, rods, spirilla and vibrioid cells. Magnetite (Fe3O4) was the only mineral identified in magnetosomes of these MTB while magnetite magnetosome crystal morphologies within the different MTB cells included cuboctahedral (present in spirilla), elongated prismatic (present in cocci and vibrios) and bullet-shaped (present in rod-shaped cells). Intracellular pH measurements using fluorescent dyes showed that the cytoplasmic pH was close to neutral in most MTB cells and acidic in some intracellular granules. Based on 16S rRNA gene phylogenetic analyses, some of the retrieved gene sequences belonged to the genus Herbaspirillum within the Betaproteobacteria class of the Proteobacteria phylum. Fluorescent in situ hybridization using a Herbaspirillum-specific probe hybridized with vibrioid MTB in magnetically-enriched samples. Transmission electron microscopy of the Herbaspirillum-like MTB revealed the presence of many intracellular granules and a single chain of elongated prismatic magnetite magnetosomes. Diverse populations of MTB have not seemed to have been described in detail in an acid environment. In addition, this is the first report of an MTB phylogenetically affiliated with Betaproteobacteria class.

  • 74.
    Abrikosov, Igor
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Ab initio modeling of materials relevant for modern energy technologies2008In: Joint ICTP-IAEA Workshop on the Training in Basic Radiation Materials Science and its Applications to Radiation Effects Studies and Development of Advanced Radiation-Resistant Materials,2008, Italy: Italy , 2008Conference paper (Refereed)
  • 75.
    Abrikosov, Igor
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Magneto-structural coupling in itinerant systems2008In: International Workshop on Ab initio Description of Iron and Steel: Magnetism and Phase Diagrams ADIS08,2008, Germany: Garmany , 2008Conference paper (Refereed)
  • 76.
    Abrikosov, Igor
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Phase stability and structural characterization of surface and thin film alloys2008In: 12th International Conference on Theoretical Aspects of Catalysis ICTAC-12,2008, Bulgaria: Bulgaria , 2008Conference paper (Refereed)
  • 77.
    Abrikosov, Igor A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Steneteg, Peter
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Hultberg, Lasse
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Hellman, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Yu Mosyagin, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Department of Theoretical Physics and Quantum Technologies, National Research, Technological University MISiS, Moscow, Russia.
    Lugovskoy, Andrey V.
    Department of Theoretical Physics and Quantum Technologies, National Research, Technological University MISiS, Russia.
    Barannikova, Svetlana A.
    Institute of Strength Physics and Materials Science, Siberian Branch of Russian Academy of Science, Tomsk, Russia; Department of Physics and Engineering, Tomsk State University, Tomsk, Russia.
    Finite Temperature, Magnetic, and Many-Body Effects in Ab Initio Simulations of Alloy Thermodynamics2013In: TMS2013 Supplemental Proceedings, John Wiley & Sons, 2013, p. 617-626Chapter in book (Refereed)
    Abstract [en]

    Ab initio electronic structure theory is known as a useful tool for prediction of materials properties. However, majority of simulations still deal with calculations in the framework of density functional theory with local or semi-local functionals carried out at zero temperature. We present new methodological solution.s, which go beyond this approach and explicitly take finite temperature, magnetic, and many-body effects into account. Considering Ti-based alloys, we discuss !imitations of the quasiharmonic approximation for the treatment of lattice vibrations, and present an accurate and easily extendable method to calculate free ,energies of strongly anharmonic solids. We underline the necessity to going beyond the state-of-the-art techniques for the determination of effective cluster interactions in systems exhibiting mctal-to-insulator transition, and describe a unified cluster expansion approach developed for this class of materials. Finally, we outline a first-principles method, disordered local moments molecular dynamics, for calculations of thermodynamic properties of magnetic alloys, like Cr1-x,.AlxN, in their high-temperature paramagnetic state. Our results unambiguously demonstrate importance of finite temperature effects in theoretical calculations ofthermodynamic properties ofmaterials.

  • 78.
    Abrikosov, Igor
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Alling, Björn
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Asker, Christian
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Ruban, A.V.
    Department of Material Science and Engineering Royal Institute of Technology.
    Phase Stabilities of Alloys From First-Principles2008In: XVII International Materials Research Congress,2008, Mexico: Mexico , 2008Conference paper (Refereed)
  • 79.
    Abrikosov, Igor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Ekholm, Marcus
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Ponomareva, Alena V.
    Theoretical Physics Department, Moscow Steel and Alloys Institute, Russua.
    Barannikova, Svetlana A.
    Institute of Strength Physics and Materials Science, Siberian Branch of Russian Academy of Science, Tomsk, Russia.
    Importance of Thermally Induced Magnetic Excitations in First-principles Simulations of Elastic Properties of Transition Metal Alloys2012In: Solid State Phenomena, ISSN 1012-0394, E-ISSN 1662-9779, Vol. 190, p. 291-294Article in journal (Refereed)
    Abstract [en]

    We demonstrate the importance of accounting for the complex magnetic ground state and finite temperature magnetic excitations in theoretical simulations of structural and elastic properties of transition metal alloys. Considering Fe72Cr16Ni12 face centered cubic (fcc) alloy, we compare results of first-principles calculations carried out for ferromagnetic and non-magnetic states, as well as for the state with disordered local moments. We show that the latter gives much more accurate description of the elastic properties for paramagnetic alloys. We carry out a determination of the magnetic ground state for fcc Fe-Mn alloys, considering collinear, as well as non-collinear states, and show the sensitively of structural and elastic properties in this system to the detailed alignment between magnetic moments. We therefore conclude that it is essential to develop accurate models of the magnetic state for the predictive description of properties of transition metal alloys.

  • 80.
    Abrikosov, Igor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Fors, Cecilia
    Nobelpriset som fortfarande är en gåta2010In: Fysikaktuellt, ISSN 0283-9148, no 2, p. 14-14Article in journal (Other (popular science, discussion, etc.))
  • 81.
    Abrikosov, Igor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Kissavos, Andreas E.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Liot, Francois
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Simak, Sergey
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Peil, O.
    Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology, SE-10044 Stockholm, Sweden.
    Ruban, A. V.
    Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology, SE-10044 Stockholm, Sweden.
    Competition between Magnetic Structures in the Fe-Rich FCC FeNi Alloys2007In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 76, no 1, p. 014434-Article in journal (Refereed)
    Abstract [en]

    We report on the results of a systematic ab initio study of the magnetic structure of Fe rich fcc FeNi binary alloys for Ni concentrations up to 50 at. %. Calculations are carried out within density-functional theory using two complementary techniques, one based on the exact muffin-tin orbital theory within the coherent potential approximation and another one based on the projector augmented-wave method. We observe that the evolution of the magnetic structure of the alloy with increasing Ni concentration is determined by a competition between a large number of magnetic states, collinear as well as noncollinear, all close in energy. We emphasize a series of transitions between these magnetic structures, in particular we have investigated a competition between disordered local moment configurations, spin spiral states, the double layer antiferromagnetic state, and the ferromagnetic phase, as well as the ferrimagnetic phase with a single spin flipped with respect to all others. We show that the latter should be particularly important for the understanding of the magnetic structure of the Invar alloys.

  • 82.
    Abrikosov, Igor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Liot, Francois
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Marten, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Smirnova, E. A.
    Theoretical Physics Department, Moscov Steel and Alloys Institute, Moscow, Russia.
    Magnetism in systems with reduced dimensionality and chemical disorder: the local environment effects2006In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 300, no 1, p. 211-215Article in journal (Refereed)
    Abstract [en]

    We study influence of the local chemical environment, the so-called local environment effects, on the electronic structure and properties of magnetic systems with reduced dimensionality and chemical disorder, and show that they play a crucial role in a vicinity of magnetic instability. As a model, we consider Fe–Ni Invar. We present results obtained from ab initio calculations of the electronic structure, magnetic moments, and exchange interactions in random fcc Fe–Ni alloy, for a single monolayer alloy film on a Cu (0 0 1) substrate as well as in the bulk. We analyze the difference between the film and the bulk magnetization, which is found to be most pronounced for dilute alloys. We also analyze a sensitivity of the individual magnetic moments and effective exchange parameters to the local chemical environment of the atoms.

  • 83.
    Abrikosov, Igor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Marten, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Olovsson, Weine
    Condensed Matter Theory Group, Department of Physics, Uppsala University, SE-751 21 Uppsala, Sweden.
    Local environment effects in random metallic alloys2005In: The Science of Complex Alloy Phases: proceedings of a symposium held during the TMS Annual Meeting and Exhibition in San Francisco, California, USA, February 13-17, 2005, to honor the Wiliam Hume-Rothery Award recipient Professor Uichiro Mizutani / [ed] Thaddeus B. Massalski and Patrice E. A. Turchi, USA: TMS , 2005, 1, p. 87-108Chapter in book (Other academic)
    Abstract [en]

    This book is published in honor of the 2005 Hume-Rothery Award Recipient, Uichiro Mizutani. It emphasizes both theoretical and experimental aspects of electronic, structural, and thermodynamic properties of complex alloy phases. Leading experts provide an assessment of our current understanding of the structural properties of complex materials, including quasicrystalline and amorphous alloys. Special emphasis is placed on our understanding of why nature is able to stabilize complex atomic arrangements and on recent results related to structurally complex alloy phases. These topics, in the spirit of the work carried out by U. Mizutani, constitute the main theme of the book

  • 84.
    Abrikosov, Igor
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Marten, Tobias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Olsson, P.
    Uppsala University.
    Simak, Sergey
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Electronic theory of materials properties: from fundamental understanding towards materials design2006Report (Other academic)
    Abstract [en]

           

  • 85.
    Abrikosov, Igor
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Mikhaylushkin, Arkady
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Asker, Christian
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Simak, Sergey
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Ab initio modeling of alloying effects at extreme conditions2008In: Second EuroMinScI Conference,2008, France: ESF , 2008Conference paper (Refereed)
    Abstract [en]

       

  • 86.
    Abrikosov, Igor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Olovsson, W.
    Uppsala University.
    Wallenius, J.
    Royal Institute of Technology.
    Ab initio simuleringar av materialegenskaper: från grundläggande teori mot design av material2004In: Nytt från NSC, no 19, p. 3-5Article in journal (Other (popular science, discussion, etc.))
  • 87.
    Abrikosov, Igor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology. NUST MISIS, Russia.
    Ponomareva, A. V.
    NUST MISIS, Russia.
    Nikonov, A. Yu.
    National Research Tomsk State University, Russia; SB RAS, Russia.
    Zharmukhambetova, A. M.
    National Research Tomsk State University, Russia.
    Mosyagin, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology. NUST MISIS, Russia.
    Lugovskoy, A. V.
    NUST MISIS, Russia.
    Hellman, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Lind, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Dmitriev, A. I.
    National Research Tomsk State University, Russia; SB RAS, Russia.
    Barannikova, S. A.
    National Research Tomsk State University, Russia; SB RAS, Russia.
    Theoretical description of pressure-induced phase transitions: a case study of Ti-V alloys2015In: High Pressure Research, ISSN 0895-7959, E-ISSN 1477-2299, Vol. 35, no 1, p. 42-48Article in journal (Refereed)
    Abstract [en]

    We discuss theoretical description of pressure-induced phase transitions by means of first-principles calculations in the framework of density functional theory. We illustrate applications of theoretical tools that allow one to take into account configurational and vibrational disorders, considering Ti-V alloys as a model system. The universality of the first-principles theory allows us to apply it in studies of different phenomena that occur in the Ti-V system upon compression. Besides the transitions between different crystal structures, we discuss isostructural transitions in bcc Ti-V alloys. Moreover, we present arguments for possible electronic transitions in this system, which may explain peculiar behaviour of elastic properties of V upon compression.

  • 88.
    Abrikosov, Igor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. National University of Science and Technology MISIS, Russia.
    Ponomareva, A. V.
    National University of Science and Technology MISIS, Russia.
    Steneteg, Peter
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Barannikova, S. A.
    National University of Science and Technology MISIS, Russia; National Research Tomsk State University, Russia; SB RAS, Russia.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Recent progress in simulations of the paramagnetic state of magnetic materials2016In: Current opinion in solid state & materials science, ISSN 1359-0286, E-ISSN 1879-0348, Vol. 20, no 2, p. 85-106Article, review/survey (Refereed)
    Abstract [en]

    We review recent developments in the field of first-principles simulations of magnetic materials above the magnetic order disorder transition temperature, focusing mainly on 3d-transition metals, their alloys and compounds. We review theoretical tools, which allow for a description of a system with local moments, which survive, but become disordered in the paramagnetic state, focusing on their advantages and limitations. We discuss applications of these theories for calculations of thermodynamic and mechanical properties of paramagnetic materials. The presented examples include, among others, simulations of phase stability of Fe, Fe-Cr and Fe-Mn alloys, formation energies of vacancies, substitutional and interstitial impurities, as well as their interactions in Fe, calculations of equations of state and elastic moduli for 3d-transition metal alloys and compounds, like CrN and steels. The examples underline the need for a proper treatment of magnetic disorder in these systems. (C) 2015 Elsevier Ltd. All rights reserved.

  • 89.
    Abrikossova, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Investigation of nanoparticle-cell interactions for development of next generation of biocompatible MRI contrast agents2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Progress in synthesis technologies and advances in fundamental understanding of materials with low dimensionality has led to the birth of a new scientific field, nanoscience, and to strong expectations of multiple applications of nanomaterials. The physical properties of small particles are unique, bridging the gap between atoms and molecules, on one side, and bulk materials on the other side. The work presented in this thesis investigates the potential of using magnetic nanoparticles as the next generation of contrast agents for biomedical imaging. The focus is on gadolinium-based nanoparticles and cellular activity including the uptake, morphology and production of reactive oxygen species.

    Gd ion complexes, like Gd chelates, are used today in the clinic, world-wide. However, there is a need for novel agents, with improved contrast capabilities and increased biocompatibility. One avenue in their design is based on crystalline nanoparticles. It allows to reduce the total number of Gd ions needed for an examination. This can be done by nanotechnology, which allows one to improve and fine tune the physico- chemical properties on the nanomaterial in use, and to increase the number of Gd atoms at a specific site that interact with protons and thereby locally increase the signal. In the present work, synthesis, purification and surface modification of crystalline Gd2O3-based nanoparticles have been performed. The nanoparticles are selected on the basis of their physical properties, that is they show enhanced magnetic properties and therefore may be of high potential interest for applications as contrast agents.

    The main synthesis method of Gd2O3 nanoparticles in this work was the modified “polyol” route, followed by purification of as-synthesized DEG-Gd2O3 nanoparticles suspensions. In most cases the purification step involved dialysis of the nanoparticle samples. In this thesis, organosilane were chosen as an exchange agent for further functionalization. Moreover, several paths have been explored for modification of the nanoparticles, including Tb3+ doping and capping with sorbitol.

    Biocompatibility of the newly designed nanoparticles is a prerequisite for their use in medical applications. Its evaluation is a complex process involving a wide range of biological phenomena. A promising path adopted in this work is to study of nanoparticle interactions with isolated blood cells. In this way one could screen nanomaterial prior to animal studies.

    The primary cell type considered in the thesis are polymorphonuclear neutrophils (PMN) which represent a type of the cells of human blood belonging to the granulocyte family of leukocytes. PMNs act as the first defense of the immune system against invading pathogens, which makes them valuable for studies of biocompatibility of newly synthesized nanoparticles. In addition, an immortalized murine alveolar macrophage cell line (MH-S), THP-1 cell line, and Ba/F3 murine bone marrow-derived cell line were considered to investigate the optimization of the cell uptake and to examine the potential of new intracellular contrast agent for magnetic resonance imaging.

    In paper I, the nanoparticles were investigated in a cellular system, as potential probes for visualization and targeting intended for bioimaging applications. The production of reactive oxygen species (ROS) by means of luminol-dependent chemiluminescence from human neutrophils was studied in presence of Gd2O3 nanoparticles. In paper II, a new design of functionalized ultra-small rare earth-based nanoparticles was reported. The synthesis was done using polyol method followed by PEGylation, and dialysis. Supersmall gadolinium oxide (DEG-Gd2O3) nanoparticles, in the range of 3-5 nm were obtained and carefully characterized. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. In paper III, cell labeling with Gd2O3 nanoparticles in hematopoietic cells was monitored by magnetic resonance imaging (MRI). In paper IV, ultra-small gadolinium oxide nanoparticles doped with terbium ions were synthesized as a potentially bifunctional material with both fluorescent and magnetic contrast agent properties. Paramagnetic behavior was studied. MRI contrast enhancement was received, and the luminescent/ fluorescent property of the particles was attributable to the Tb3+ ion located on the crystal lattice of the Gd2O3 host. Fluorescent labeling of living cells was obtained. In manuscript V, neutrophil granulocytes were investigated with rapid cell signaling communicative processes in time frame of minutes, and their response to cerium-oxide based nanoparticles were monitored using capacitive sensors based on Lab-on-a-chip technology. This showed the potential of label free method used to measure oxidative stress of neutrophil granulocytes. In manuscript VI, investigations of cell-(DEGGd2O3) nanoparticle interactions were carried out. Plain (DEG-Gd2O3) nanoparticles, (DEG-Gd2O3) nanoparticles in presence of sorbitol and (DEG-Gd2O3) nanoparticles capped with sorbitol were studied. Relaxation studies and measurements of the reactive oxygen species production by neutrophils were based on chemiluminescence. Cell morphology was evaluated as a parameter of the nanoparticle induced inflammatory response by means of the fluorescence microscopy.

    The thesis demonstrates high potential of novel Gd2O3-based nanoparticles for development of the next generation contrast agents, that is to find biocompatible compounds with high relaxivity that can be detected at lower doses, and in the future enable targeting to provide great local contrast.

    List of papers
    1. Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes
    Open this publication in new window or tab >>Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes
    Show others...
    2012 (English)In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 23, no 27, p. 275101-Article in journal (Refereed) Published
    Abstract [en]

    We have previously shown that gadolinium oxide (Gd2O3) nanoparticles are promising candidates to be used as contrast agents in magnetic resonance (MR) imaging applications. In this study, these nanoparticles were investigated in a cellular system, as possible probes for visualization and targeting intended for bioimaging applications. We evaluated the impact of the presence of Gd2O3 nanoparticles on the production of reactive oxygen species (ROS) from human neutrophils, by means of luminol-dependent chemiluminescence. Three sets of Gd2O3 nanoparticles were studied, i.e. as synthesized, dialyzed and both PEG-functionalized and dialyzed Gd2O3 nanoparticles. In addition, neutrophil morphology was evaluated by fluorescent staining of the actin cytoskeleton and fluorescence microscopy. We show that surface modification of these nanoparticles with polyethylene glycol (PEG) is essential in order to increase their biocompatibility. We observed that the as synthesized nanoparticles markedly decreased the ROS production from neutrophils challenged with prey (opsonized yeast particles) compared to controls without nanoparticles. After functionalization and dialysis, more moderate inhibitory effects were observed at a corresponding concentration of gadolinium. At lower gadolinium concentration the response was similar to that of the control cells. We suggest that the diethylene glycol (DEG) present in the as synthesized nanoparticle preparation is responsible for the inhibitory effects on the neutrophil oxidative burst. Indeed, in the present study we also show that even a low concentration of DEG, 0.3%, severely inhibits neutrophil function. In summary, the low cellular response upon PEG-functionalized Gd2O3 nanoparticle exposure indicates that these nanoparticles are promising candidates for MR-imaging purposes.

    Place, publisher, year, edition, pages
    Institute of Physics, 2012
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-79667 (URN)10.1088/0957-4484/23/27/275101 (DOI)000305802000001 ()
    Available from: 2012-08-14 Created: 2012-08-13 Last updated: 2018-11-12
    2. Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement
    Open this publication in new window or tab >>Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement
    Show others...
    2010 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, no 8, p. 5753-5762Article in journal (Refereed) Published
    Abstract [en]

    Recently, much attention has been given to the development of biofunctionalized nanoparticles with magnetic properties for novel biomedical imaging. Guided, smart, targeting nanoparticulate magnetic resonance imaging (MRI) contrast agents inducing high MRI signal will be valuable tools for future tissue specific imaging and investigation of molecular and cellular events. In this study, we report a new design of functionalized ultrasmall rare earth based nanoparticles to be used as a positive contrast agent in MRI. The relaxivity is compared to commercially available Gd based chelates. The synthesis, PEGylation, and dialysis of small (3−5 nm) gadolinium oxide (DEG-Gd2O3) nanoparticles are presented. The chemical and physical properties of the nanomaterial were investigated with Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and dynamic light scattering. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. The proton relaxation times as a function of dialysis time and functionalization were measured at 1.5 T. A capping procedure introducing stabilizing properties was designed and verified, and the dialysis effects were evaluated. A higher proton relaxivity was obtained for as-synthesized diethylene glycol (DEG)-Gd2O3 nanoparticles compared to commercial Gd-DTPA. A slight decrease of the relaxivity for as-synthesized DEG-Gd2O3 nanoparticles as a function of dialysis time was observed. The results for functionalized nanoparticles showed a considerable relaxivity increase for particles dialyzed extensively with r1 and r2 values approximately 4 times the corresponding values for Gd-DTPA. The microscopy study showed that PEGylated nanoparticles do not activate neutrophils in contrast to uncapped Gd2O3. Finally, the nanoparticles are equipped with Rhodamine to show that our PEGylated nanoparticles are available for further coupling chemistry, and thus prepared for targeting purposes. The long term goal is to design a powerful, directed contrast agent for MRI examinations with specific targeting possibilities and with properties inducing local contrast, that is, an extremely high MR signal at the cellular and molecular level.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2010
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-54946 (URN)10.1021/la903566y (DOI)000276562300061 ()
    Available from: 2010-04-23 Created: 2010-04-23 Last updated: 2018-10-29Bibliographically approved
    3. Gd2O3 nanoparticles in hematopoietic cells for MRI contrast enhancement
    Open this publication in new window or tab >>Gd2O3 nanoparticles in hematopoietic cells for MRI contrast enhancement
    Show others...
    2011 (English)In: International journal of nano medicine, ISSN 1178-2013, Vol. 6, p. 3233-3240Article in journal (Refereed) Published
    Abstract [en]

    As the utility of magnetic resonance imaging (MRI) broadens, the importance of having specific and efficient contrast agents increases and in recent time there has been a huge development in the fields of molecular imaging and intracellular markers. Previous studies have shown that gadolinium oxide (Gd2O3) nanoparticles generate higher relaxivity than currently available Gd chelates: In addition, the Gd2O3 nanoparticles have promising properties for MRI cell tracking. The aim of the present work was to study cell labeling with Gd2O3 nanoparticles in hematopoietic cells and to improve techniques for monitoring hematopoietic stem cell migration by MRI. Particle uptake was studied in two cell lines: the hematopoietic progenitor cell line Ba/F3 and the monocytic cell line THP-1. Cells were incubated with Gd2O3 nanoparticles and it was investigated whether the transfection agent protamine sulfate increased the particle uptake. Treated cells were examined by electron microscopy and MRI, and analyzed for particle content by inductively coupled plasma sector field mass spectrometry. Results showed that particles were intracellular, however, sparsely in Ba/F3. The relaxation times were shortened with increasing particle concentration. Relaxivities, r1 and r2 at 1.5 T and 21°C, for Gd2O3 nanoparticles in different cell samples were 3.6–5.3 s-1 mM-1 and 9.6–17.2 s-1 mM-1, respectively. Protamine sulfate treatment increased the uptake in both Ba/F3 cells and THP-1 cells. However, the increased uptake did not increase the relaxation rate for THP-1 as for Ba/F3, probably due to aggregation and/or saturation effects. Viability of treated cells was not significantly decreased and thus, it was concluded that the use of Gd2O3 nanoparticles is suitable for this type of cell labeling by means of detecting and monitoring hematopoietic cells. In conclusion, Gd2O3 nanoparticles are a promising material to achieve positive intracellular MRI contrast; however, further particle development needs to be performed.

    Place, publisher, year, edition, pages
    Manchester, UK: Dove Medical Press Ltd, 2011
    Keywords
    gadolinium oxide, magnetic resonance imaging, contrast agent, cell labeling, Ba/F3 cells, THP-1 cells
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-72275 (URN)10.2147/IJN.S23940 (DOI)000298164300001 ()
    Note

    funding agencies|Swedish Research Council| 621-2007-3810 621-2009-5148 521-2009-3423 |VINNOVA| 2009-00194 |Center in Nanoscience and Technology at LiTH (CeNano)||

    Available from: 2011-11-24 Created: 2011-11-24 Last updated: 2018-10-29
    4. Synthesis and Characterization of Tb3+-Doped Gd2O3 Nanocrystals: A Bifunctional Material with Combined Fluorescent Labeling and MRI Contrast Agent Properties
    Open this publication in new window or tab >>Synthesis and Characterization of Tb3+-Doped Gd2O3 Nanocrystals: A Bifunctional Material with Combined Fluorescent Labeling and MRI Contrast Agent Properties
    Show others...
    2009 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, no 17, p. 6913-6920Article in journal (Refereed) Published
    Abstract [en]

    Ultrasmall gadolinium oxide nanoparticles doped with terbium ions were synthesized by the polyol route and characterized as a potentially bifunctional material with both fluorescent and magnetic contrast agent properties. The structural, optical, and magnetic properties of the organic-acid-capped and PEGylated Gd2O3:Tb3+ nanocrystals were studied by HR-TEM, XPS, EDX, IR, PL, and SQUID. The luminescent/fluorescent property of the particles is attributable to the Tb3+ ion located on the crystal lattice of the Gd2O3 host. The paramagnetic behavior of the particles is discussed. Pilot studies investigating the capability of the nanoparticles for fluorescent labeling of living cells and as a MRI contrast agent were also performed. Cells of two cell lines (THP-1 cells and fibroblasts) were incubated with the particles, and intracellular particle distribution was visualized by confocal microscopy. The MRI relaxivity of the PEGylated nanoparticles in water at low Gd concentration was assessed showing a higher T-1 relaxation rate compared to conventional Gd-DTPA chelates and comparable to that of undoped Gd2O3 nanoparticles.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-12944 (URN)10.1021/jp808708m (DOI)000265529700009 ()
    Note

    On the day of the defence date the status of this article was Submitted

    Available from: 2008-02-21 Created: 2008-02-21 Last updated: 2018-10-29Bibliographically approved
  • 90.
    Abrikossova, Natalia
    Linköping University, The Department of Physics, Chemistry and Biology.
    In-vitro studier av inflammatorisk svar från helblod och neutrofila granulocyter vid aktivering med nanopartiklar2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [sv]

    Syftet med detta arbete var att studera inflammatoriska effekter i mänskligt helblod och neutrofila granulocyter exponerade och stimulerade av nanopartiklar av gadoliniumoxid. Projektet utreder den toxiska potentialen hos nanopartiklar med olika kemiska och morfologiska egenskaper.

    I experimenten undersöktes cellresponsen hos blodceller exponerade med ofunktionaliserade och funktionaliserade nanopartiklarna. Effekterna av funktionaliserade och ofunktionaliserade nanopartiklarna på aggregation och syreradikalproduktion i helblod och hos neutrofila granulocyter studerades med hjälp av lumi-aggregometri.

    Studier har visat att varken ofunktionaliserade eller funktionaliserade nanopartiklarna ger aggregation i blodet. Syreradikalproduktionen ökar däremot. Resultaten av studier i helblod visar att stimulering med spädnings serier av funktionaliserade nanopartiklar ger mindre frisättning av syreradikaler än spädnings serier med ofunktionaliserade nanopartiklar. Detta bekräftas med studier av morfologiska skillnader i neutrofila granulocyter som var stimulerade med olika typer av nanopartiklar. Detta gjordes med hjälp av fluorescensmikroskopi. Resultaten från studierna tyder på att funktionaliserade nanopartiklar är mindre inflammatoriska än ofunktionaliserade nanopartiklar.

  • 91.
    Abrouk, Michael
    et al.
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Balcarkova, Barbora
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Simkova, Hana
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Kominkova, Eva
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Martis, Mihaela-Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences. Institute for Bioinformatics and Systems Biology, Helmholtz Center Munich, Neuherberg, Germany.
    Jakobson, Irena
    Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 19086, Estonia.
    Timofejeva, Ljudmilla
    Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 19086, Estonia.
    Rey, Elodie
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Vrana, Jan
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Kilian, Andrzej
    Diversity Arrays Technology Pty Ltd, Yarralumla, ACT2600, Australia.
    Järve, Kadri
    Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 19086, Estonia.
    Dolezel, Jaroslav
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Valarik, Miroslav
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    The in silico identification and characterization of a bread wheat/Triticum militinae introgression line: Characterization of alien introgression in wheat2017In: Plant Biotechnology Journal, ISSN 1467-7644, E-ISSN 1467-7652, Vol. 15, no 2, p. 249-256Article in journal (Refereed)
    Abstract [en]

    The capacity of the bread wheat (Triticum aestivum) genome to tolerate introgression from related genomes can be exploited for wheat improvement. A resistance to powdery mildew expressed by a derivative of the cross bread wheat cv. Tähti ⨯ T. militinae (Tm) is known to be due to the incorporation of a Tm segment into the long arm of chromosome 4A. Here, a newly developed in silico method termed RICh (rearrangement identification and characterization) has been applied to characterize the introgression. A virtual gene order, assembled using the GenomeZipper approach, was obtained for the native copy of chromosome 4A; it incorporated 570 4A DArTseq markers to produce a zipper comprising 2,132 loci. A comparison between the native and introgressed forms of the 4AL chromosome arm showed that the introgressed region is located at the distal part of the arm. The Tm segment, derived from chromosome 7G, harbors 131 homoeologs out of the 357 genes present on the corresponding region of Chinese Spring 4AL. The estimated number of Tm genes transferred along with the disease resistance gene was 169. Characterizing the introgression's position, gene content and internal gene order should facilitate not only gene isolation, but may also be informative with respect to chromatin structure and behavior studies.

  • 92.
    Abu Baker, Mohamed
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory.
    Agile Prototyping: A combination of different approaches into one main process2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Software prototyping is considered to be one of the most important tools that are used by software engineersnowadays to be able to understand the customer’s requirements, and develop software products that are efficient,reliable, and acceptable economically. Software engineers can choose any of the available prototyping approaches tobe used, based on the software that they intend to develop and how fast they would like to go during the softwaredevelopment. But generally speaking all prototyping approaches are aimed to help the engineers to understand thecustomer’s true needs, examine different software solutions and quality aspect, verification activities…etc, that mightaffect the quality of the software underdevelopment, as well as avoiding any potential development risks.A combination of several prototyping approaches, and brainstorming techniques which have fulfilled the aim of theknowledge extraction approach, have resulted in developing a prototyping approach that the engineers will use todevelop one and only one throwaway prototype to extract more knowledge than expected, in order to improve thequality of the software underdevelopment by spending more time studying it from different points of view.The knowledge extraction approach, then, was applied to the developed prototyping approach in which thedeveloped model was treated as software prototype, in order to gain more knowledge out of it. This activity hasresulted in several points of view, and improvements that were implemented to the developed model and as a resultAgile Prototyping AP, was developed. AP integrated more development approaches to the first developedprototyping model, such as: agile, documentation, software configuration management, and fractional factorialdesign, in which the main aim of developing one, and only one prototype, to help the engineers gaining moreknowledge, and reducing effort, time, and cost of development was accomplished but still developing softwareproducts with satisfying quality is done by developing an evolutionary prototyping and building throwawayprototypes on top of it.

  • 93.
    Abugessaisa, Imad
    Linköping University, Department of Computer and Information Science, GIS - Geographical Information Science Group. Linköping University, The Institute of Technology.
    Analytical tools and information-sharing methods supporting road safety organizations2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A prerequisite for improving road safety are reliable and consistent sources of information about traffic and accidents, which will help assess the prevailing situation and give a good indication of their severity. In many countries there is under-reporting of road accidents, deaths and injuries, no collection of data at all, or low quality of information. Potential knowledge is hidden, due to the large accumulation of traffic and accident data. This limits the investigative tasks of road safety experts and thus decreases the utilization of databases. All these factors can have serious effects on the analysis of the road safety situation, as well as on the results of the analyses.

    This dissertation presents a three-tiered conceptual model to support the sharing of road safety–related information and a set of applications and analysis tools. The overall aim of the research is to build and maintain an information-sharing platform, and to construct mechanisms that can support road safety professionals and researchers in their efforts to prevent road accidents. GLOBESAFE is a platform for information sharing among road safety organizations in different countries developed during this research.

    Several approaches were used, First, requirement elicitation methods were used to identify the exact requirements of the platform. This helped in developing a conceptual model, a common vocabulary, a set of applications, and various access modes to the system. The implementation of the requirements was based on iterative prototyping. Usability methods were introduced to evaluate the users’ interaction satisfaction with the system and the various tools. Second, a system-thinking approach and a technology acceptance model were used in the study of the Swedish traffic data acquisition system. Finally, visual data mining methods were introduced as a novel approach to discovering hidden knowledge and relationships in road traffic and accident databases. The results from these studies have been reported in several scientific articles.

    List of papers
    1. Ontological Approach to Modeling Information Systems
    Open this publication in new window or tab >>Ontological Approach to Modeling Information Systems
    2004 (English)In: Proceedings of the Fourth International Conference on Computer and information Technology (Cit'04), 14–16 September, Wuhan, China: IEEE Computer Society, Washington, DC, 2004, p. 1122-1127Conference paper, Published paper (Other academic)
    Abstract [en]

    In recent years, the use of formal tools in information system modeling and development represents a potential area of research in computer science. In 1967, the term ontology appeared for the first time in computer science literature as S. H. Mealy introduced it as a basic foundation in data modeling. The main objective of this paper is to discuss the concept of ontology (from a philosophical perspective) as it was used to bridge the gap between philosophy and information systems science, and to investigate ontology types that can be found during ontological investigation and the methods used in the investigation process. The secondary objective of this paper is to study different design and engineering approaches of ontology as well as development environments that are used to create and edit ontologies.

    Keywords
    Ontology, Conceptual Model
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13184 (URN)10.1109/CIT.2004.1357345 (DOI)
    Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2009-04-21
    2. Benchmarking Road Safety Situations Using OGC Model of Portrayal Workflow
    Open this publication in new window or tab >>Benchmarking Road Safety Situations Using OGC Model of Portrayal Workflow
    2005 (English)In: Proceedings of the 13th International Conference on Geoinformatics (GeoInformatics’5), 17-19 August, Toronto, Canada: Ryerson University, 2005Conference paper, Published paper (Other academic)
    Keywords
    road safety, benchmarking, OGC model
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13185 (URN)
    Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2009-04-21
    3. Map as Interface for Shared Information: A Study of Design Principles and User Interaction Satisfaction
    Open this publication in new window or tab >>Map as Interface for Shared Information: A Study of Design Principles and User Interaction Satisfaction
    2006 (English)In: IADIS International Conference WWW/Internet 2006: Murcia, Spain, 2006, p. 377-384Conference paper, Published paper (Refereed)
    Keywords
    Maps, shared information, design priciples, user satisfaction
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13186 (URN)972-8924-19-4 (ISBN)
    Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2009-02-05Bibliographically approved
    4. GLOBESAFE: A Platform for Information-Sharing Among Road Safety Organizations
    Open this publication in new window or tab >>GLOBESAFE: A Platform for Information-Sharing Among Road Safety Organizations
    2007 (English)In: IFIP-W.G. 9th International Conference on Social Implications of Computers in Developing Countries: May 2007, São Paulo, Brazil, 2007, p. 1-10Conference paper, Published paper (Refereed)
    Keywords
    information sharing, road safety
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13187 (URN)
    Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2009-04-23Bibliographically approved
    5. A Systemic View on Swedish Traffic Accident Data Acquisition System
    Open this publication in new window or tab >>A Systemic View on Swedish Traffic Accident Data Acquisition System
    2007 (English)In: Proceedings of the 14th International Conference on Road Safety on Four Continents (RS4C), 14-16 November, Bangkok, Thailand, Sweden: VTI , 2007, p. 1-12Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper presents work in progress to study information sharing among road safety organizations. The focus is to study accident data acquisition system. In 2002, Swedish Road Transport authority (SRT) has accepted STRADA as accident reporting system to be used by the police all over Sweden. Such system is vital for coordinating, maintaining and auditing road safety in the country. Normally road accidents are reported by the police or by Emergency unit at the hospital. However more than 50% of the hospitals in Sweden didn’t use the system which decrease the utilization of the system and reduce the quality of the information that demanded. By using system thinking approach in this study we try to see why such situation is occurred and how changes can be introduced and handle to overcome such problem. Interviews conducted with focus group and different users of the system. To investigate the issues related to the acceptance of the system we use Technology Acceptance Model (TAM). We recommend getting the user involved in the life cycle of the STRADA and also the developers could use enabling system to overcome problems in related to system usability and complexity. Also we suggest the use of iterative development to govern the life cycle.

    Place, publisher, year, edition, pages
    Sweden: VTI, 2007
    Keywords
    STRADA Information sharing Road accidents recording system
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13188 (URN)
    Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2009-04-23Bibliographically approved
    6. Knowledge Discovery in Road Accidents Database Integration of Visual and Automatic Data Mining Methods
    Open this publication in new window or tab >>Knowledge Discovery in Road Accidents Database Integration of Visual and Automatic Data Mining Methods
    2008 (English)In: International Journal of Public Information Systems, ISSN 1653-4360, Vol. 1, p. 59-85Article in journal (Refereed) Published
    Abstract [en]

    Road accident statistics are collected and used by a large number of users and this can result in a huge volume of data which requires to be explored in order to ascertain the hidden knowledge. Potential knowledge may be hidden because of the accumulation of data, which limits the exploration task for the road safety expert and, hence, reduces the utilization of the database. In order to assist in solving these problems, this paper explores Automatic and Visual Data Mining (VDM) methods. The main purpose is to study VDM methods and their applicability to knowledge discovery in a road accident databases. The basic feature of VDM is to involve the user in the exploration process. VDM uses direct interactive methods to allow the user to obtain an insight into and recognize different patterns in the dataset. In this paper, I apply a range of methods and techniques, including a paradigm for VDM, exploratory data analysis, and clustering methods, such as K-means algorithms, hierarchical agglomerative clustering (HAC), classification trees, and self-organized-maps (SOM). These methods assist in integrating VDM with automatic data mining algorithms. Open source VDM tools offering visualization techniques were used. The first contribution of this paper lies in the area of discovering clusters and different relationships (such as the relationship between socioeconomic indicators and fatalities, traffic risk and population, personal risk and car per capita, etc.) in the road safety database. The methods used were very useful and valuable for detecting clusters of countries that share similar traffic situations. The second contribution was the exploratory data analysis where the user can explore the contents and the structure of the data set at an early stage of the analysis. This is supported by the filtering components of VDM. This assists expert users with a strong background in traffic safety analysis to be able to intimate assumptions and hypotheses concerning future situations. The third contribution involved interactive explorations based on brushing and linking methods; this novel approach assists both the experienced and inexperienced users to detect and recognize interesting patterns in the available database. The results obtained showed that this approach offers a better understanding of the contents of road safety databases, with respect to current statistical techniques and approaches used for analyzing road safety situations.

    Keywords
    Visual data mining, K-Means, HAC, SOM, InfoVis, IRTAD, GLOBESAFE
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13189 (URN)
    Available from: 2008-04-28 Created: 2008-04-28 Last updated: 2009-01-26
  • 94.
    Abys, JA
    et al.
    Lucent Technol Electroplating Chem & Serv, Murray Hill, NJ 07974 USA Molex Inc, Lisle, IL USA CSM Mat Tekn Ab, Linkoping, Sweden.
    Breck, GF
    Lucent Technol Electroplating Chem & Serv, Murray Hill, NJ 07974 USA Molex Inc, Lisle, IL USA CSM Mat Tekn Ab, Linkoping, Sweden.
    Straschil, HK
    Lucent Technol Electroplating Chem & Serv, Murray Hill, NJ 07974 USA Molex Inc, Lisle, IL USA CSM Mat Tekn Ab, Linkoping, Sweden.
    Boguslavsky, I
    Lucent Technol Electroplating Chem & Serv, Murray Hill, NJ 07974 USA Molex Inc, Lisle, IL USA CSM Mat Tekn Ab, Linkoping, Sweden.
    Holmbom, G
    Lucent Technol Electroplating Chem & Serv, Murray Hill, NJ 07974 USA Molex Inc, Lisle, IL USA CSM Mat Tekn Ab, Linkoping, Sweden.
    New methods for coating surfaces - Palladium-cobalt alloy for electrical engineering and electronics1999In: Metall (Berlin. 1947), ISSN 0026-0746, Vol. 53, no 11, p. 622-625Article in journal (Refereed)
  • 95.
    Accardi, Luigi
    et al.
    Università di Roma “Tor Vergata”, Italy.
    Belavkin, V. P.
    University of Nottingham, UK.
    Kent, Johyn T.
    University of Leeds, UK.
    Brody, Dorje C.
    Imperial College, London, UK.
    Bingham, N. H.
    Brunel University, Uxbridge, UK.
    Frey, Jeremy G.
    University of Southampton, UK.
    Helland, Inge S.
    University of Oslo, Norway.
    Larsson, Jan-Åke
    Linköping University, Department of Mathematics, Applied Mathematics. Linköping University, The Institute of Technology.
    Majumdar, N. K.
    London, UK.
    Minozzo, Marco
    University of Perugia, Italy.
    Thompson, J. W.
    University of Hull, UK.
    Discussion on “On quantum statistical inference” by O. E. Barndorff-Nielsen, R. D. Gill and P.E. Jupp2003In: Journal of The Royal Statistical Society Series B-statistical Methodology, ISSN 1369-7412, E-ISSN 1467-9868, Vol. 65, no 4, p. 805-816p. 805-816Article in journal (Refereed)
  • 96.
    Achichi, Manel
    et al.
    Laboratoire d'Informatique, de Robotique et de Microélectronique de Montpellier (LIRMM), France; University of Montpellier, France.
    Cheatham, Michelle
    Wright State University, USA.
    Dragisic, Zlatan
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    Euzenat, Jerome
    INRIA, France; University Grenoble Alpes, Grenoble, France.
    Faria, Daniel
    Instituto Gulbenkian de Ciencia, Lisbon, Portugal.
    Ferrara, Alfio
    Universita degli studi di Milano, Italy.
    Flouris, Giorgos
    Institute of Computer Science-FORTH, Heraklion, Greece.
    Fundulaki, Irini
    Institute of Computer Science-FORTH, Heraklion, Greece.
    Harrow, Ian
    Pistoia Alliance Inc., USA.
    Ivanova, Valentina
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    Jimenez-Ruiz, Ernesto
    University of Oslo, Norway.
    Kolthoff, Kristian
    University of Mannheim, Germany.
    Kuss, Elena
    University of Mannheim, Germany.
    Lambrix, Patrick
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    Leopold, Henrik
    Vrije Universiteit Amsterdam, Netherlands.
    Li, Huanyu
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, Faculty of Science & Engineering.
    Meilicke, Christian
    University of Mannheim, Germany.
    Mohammadi, Majid
    Technical University of Delft, Netherlands.
    Montanelli, Stefano
    Universita degli studi di Milano, Italy.
    Pesquita, Catia
    Universidade de Lisboa, Portugal.
    Saveta, Tzanina
    Institute of Computer Science-FORTH, Heraklion, Greece.
    Shvaiko, Pavel
    Informatica Trentina, Trento, Italy.
    Splendiani, Andrea
    Pistoia Alliance Inc., USA.
    Stuckenschmidt, Heiner
    University of Mannheim, Germany.
    Thieblin, Elodie
    Institut de Recherche en Informatique de Toulouse (IRIT), France; Universite Toulouse II, Toulouse, France.
    Todorov, Konstantin
    Laboratoire d'Informatique, de Robotique et de Microélectronique de Montpellier (LIRMM), France; University of Montpellier, France.
    Trojahn, Cassia
    Institut de Recherche en Informatique de Toulouse (IRIT); Universite Toulouse II, Toulouse, France.
    Zamazal, Ondrej
    University of Economics, Prague, Czech Republic.
    Results of the Ontology Alignment Evaluation Initiative 20172017In: Proceedings of the 12th International Workshop on Ontology Matching co-located with the 16th International Semantic Web Conference (ISWC 2017) / [ed] Pavel Shvaiko, Jerome Euzenat, Ernesto Jimenez-Ruiz, Michelle Cheatham, Oktie Hassanzadeh, Aachen, Germany: CEUR Workshop Proceedings , 2017, p. 61-113Conference paper (Refereed)
  • 97.
    Achichi, Manel
    et al.
    LIRMM, University of Montpellier, France.
    Cheatham, Michelle
    Wright State University, USA.
    Dragisic, Zlatan
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    Euzenat, Jerome
    INRIA, France; Univ. Grenoble Alpes, Grenoble, France.
    Faria, Daniel
    Instituto Gulbenkian de Ciencia, Lisbon, Portugal.
    Ferrara, Alfio
    Universita degli studi di Milano, Italy.
    Flouris, Giorgos
    Institute of Computer Science-FORTH, Heraklion, Greece.
    Fundulaki, Irini
    Institute of Computer Science-FORTH, Heraklion, Greece.
    Harrow, Ian
    Pistoia Alliance Inc., USA.
    Ivanova, Valentina
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    Jiménez-Ruiz, Ernesto
    University of Oslo, Norway; University of Oxford, UK.
    Kuss, Elena
    University of Mannheim, Germany.
    Lambrix, Patrick
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    Leopold, Henrik
    Vrije Universiteit Amsterdam, The Netherlands.
    Li, Huanyu
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, Faculty of Science & Engineering.
    Meilicke, Christian
    University of Mannheim, Germany.
    Montanelli, Stefano
    Universita degli studi di Milano, Italy.
    Pesquita, Catia
    Universidade de Lisboa, Portugal.
    Saveta, Tzanina
    Institute of Computer Science-FORTH, Heraklion, Greece.
    Shvaiko, Pavel
    TasLab, Informatica Trentina, Trento, Italy.
    Splendiani, Andrea
    Novartis Institutes for Biomedical Research, Basel, Switzerland.
    Stuckenschmidt, Heiner
    University of Mannheim, Germany.
    Todorov, Konstantin
    LIRMM, University of Montpellier, France.
    Trojahn, Cassia
    IRIT, Toulouse, France; Université Toulouse II, Toulouse, France.
    Zamazal, Ondřej
    University of Economics, Prague, Czech Republic.
    Results of the Ontology Alignment Evaluation Initiative 20162016In: Proceedings of the 11th International Workshop on Ontology Matching, Aachen, Germany: CEUR Workshop Proceedings , 2016, p. 73-129Conference paper (Refereed)
  • 98.
    Achu, Denis
    Linköping University, Department of Computer and Information Science.
    Application of Gis in Temporal and Spatial Analyses of Dengue Fever Outbreak: Case of Rio de Janeiro, Brazil2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Since Dengue fever (DF) and its related forms, Dengue Hemorrhagic fever (DHF) and Dengue Shock Syndrome (DSS) have become important health concerns worldwide, it is also imperative to develop methods which will help in the analysis of the incidences. Dengue fever cases are growing in number as it also invades widely, affecting larger number of countries and crossing climatic boundaries. Considering that the disease as of now has neither an effective vaccine nor a cure, monitoring in order to prevent or control is the resorted alternative. GIS and its related technologies offer a wealth of interesting capabilities towards achieving this goal.

    The intention of this study was to develop methods to describe dengue fever outbreaks taking Rio de Janeiro, Brazil as a case study. Careful study of Census data with appropriate attributes was made to find out their potential influence on dengue fever incidence in the various regions or census districts. Dengue incidence data from year 2000 to year 2008 reported by the municipal secretariat of Rio was used to extract the necessary census districts. Base map files in MapInfo format were converted to shape files.  Using ArcGIS it was possible to merge the dengue fever incidence data with the available base map file of the City of Rio according to corresponding census districts. Choropleth maps were then created using different attributes from which patterns and trends could be used to describe the characteristic of the outbreak with respect to the socio-economic conditions. Incidence data were also plotted in Excel to see temporal variations. Cluster analysis were performed with the Moran I technique on critical periods and years of dengue outbreak. Using the square root of dengue incidence from January to April 2002 and 2008, inverse distance was selected as the conceptualised spatial relationship, Euclidean distance as the distance method. More detailed analyses were then done on the selected critical years of dengue outbreak, (years 2002 and 2008), to investigate the influence of socio-economic variables on dengue incidence per census district.

     

    Dengue incidence rate appeared to be higher during the rainy and warmer months between December and May. Outbreaks of dengue occurred in years 2002 and 2008 over the study period of year 2000 to 2008. Some factors included in the census data were influential in the dengue prevalence according to districts. Satisfactory results can be achieved by using this strategy as a quick method for assessing potential dengue attack, spread and possible enabling conditions. The method has the advantage where there is limited access to field work, less financial means for acquisition of data and other vital resources.

    A number of difficulties were encountered during the study however and leaves areas where further work can be done for improvements. More variables would be required in order to make a complete and comprehensive description of influential conditions and factors.  There is still a gap in the analytical tools required for multi-dimensional investigations as the ones encountered in this study.  It is vital to integrate ‘GPS’ and ‘Remote Sensing’ in order to obtain a variety of up-to-date data with higher resolution.

     

  • 99.
    Achu Nges, Ivo
    et al.
    Department of Biotechnology, Lund Univeristy.
    Björn, Annika
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Björnsson, Lovisa
    Department of Biotechnology, Lund University.
    Stable operation during pilot-scale anaerobic digestion of nutrient-supplemented maize/sugar beet silage2012In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 118, p. 445-454Article in journal (Refereed)
    Abstract [en]

    Biogas production from maize/sugar beet silage was studied under mesophilic conditions in a continuous stirred tank reactor pilot-scale process. While energy crop mono-digestion is often performed with very long hydraulic retention times (HRTs), the present study demonstrated an efficient process operating with a 50-day HRT and a corrected total solids (TScorr) based organic loading rate of 3.4 kg/m3×d. The good performance was attributed to supplementation with both macro- and micronutrients and was evidenced by good methane yields (318 m3/ton TScorr) which were comparable to laboratory maximum expected yields plus low total volatile fatty acid concentrations (< 0.8 g/L). A viscoplastic and thixotropic digester fluid behaviour was observed, and the viscosity problems common in crop mono-digestion were not seen in this study. The effluent also complied with Swedish certification standards for bio-fertilizer for farmland application. Nutrient addition thus rendered a stable biogas process, while the effluent was a good quality bio-fertilizer.

  • 100.
    Ackelman, Jenny
    Linköping University, Department of Physics, Chemistry and Biology.
    Alternative splicing and its regulation under normal and abnormal conditions2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    During the maturation of pre-mRNA introns are removed and exons are spliced together, to form a primary transcript, a reaction that is catalyzed by the spliceosome. Alternative splicing is a complex reaction that mainly utilizes one of four mechanisms; exon skipping, 5’ splice site choice, 3’ splice site choice and intron retention. To achieve accurate splicing four sequence elements are essential, two of which are located in the splice sites themselves; 5’ splice sites and 3’ splice sites, but also the polypyrimidine tract and the branch point sequence. Alternative splicing can be regulated by histone or chromatin modulations, siRNA, transcription efficiency and various proteins, many of which belong to either the SR protein family or the hnRNP family of proteins. SR proteins usually promote exon inclusion, while hnRNP proteins usually promote exon skipping. There are also regulatory elements that are called exonic splicing enhancers or silencers depending on if they promote or inhibit the inclusion of the exon they reside in. These elements also exist in introns and are then called intronic splicing enhancers or silencers. The enhancer elements are most commonly targeted by SR proteins and the silencer elements are usually targeted by hnRNP proteins. This paper will mainly focus on the regulation of alternative splicing and the role of alternative splicing under abnormal conditions, such as when mutations cause disease.

1234567 51 - 100 of 20165
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf