liu.seSearch for publications in DiVA
Change search
Refine search result
1234567 1 - 50 of 1325
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • 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)
  • 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)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1.
    Du, Chun
    et al.
    Chinese Academy of Science.
    Li, Cuihong
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Li, Weiwei
    Chinese Academy of Science.
    Chen, Xiong
    Chinese Academy of Science.
    Bo, Zhishan
    Beijing Normal University.
    Veit, Clemens
    Fraunhofer Institute for Solar Energy Systems ISE.
    Ma, Zaifei
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wuerfel, Uli
    Fraunhofer Institute for Solar Energy Systems ISE.
    Zhu, Hongfei
    Chinese Academy of Science.
    Hu, Wenping
    Chinese Academy of Science.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    9-Alkylidene-9H-Fluorene-Containing Polymer for High-Efficiency Polymer Solar Cells2011In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 44, no 19, 7617-7624 p.Article in journal (Refereed)
    Abstract [en]

    A novel donor-acceptor copolymer containing 9-alkylidene-9H-fluorene unit in the main chain, poly[9-(1-hexylheptylidene)-2,7-fluorene-alt-5, 5-(4,7-di-2-thienyl-5,6-dialkoxy-2,1,3-benzothiadiazole)] (PAFDTBT), has been synthesized and evaluated in bulk heterojunction polymer solar cells (BHJ PSCs). The polymer possesses a low band gap of 1.84 eV, a low-lying HOMO energy level (5.32 eV), and excellent solubility in common organic solvents. PSCs based on PAFDTBT and (6,6)-phenyl-C(71)-butyric add methyl ester (PC(71)BM) demonstrate a power conversion efficiency (PCE) of 6.2% with a high fill factor (FF) of 0.70, which indicates that 9-alkylidene-9H-fluorene can be a very useful building block for constructing narrow band gap conjugated polymers for high-efficiency BHJ PSCs.

  • 2.
    Eklund, Anders
    et al.
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Science & Engineering. Linköping University, Faculty of Arts and Sciences.
    Lindqvist, Martin A
    Department of Biostatistics, Johns Hopkins University, Baltimore, USA.
    Villani, Mattias
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    A Bayesian Heteroscedastic GLM with Application to fMRI Data with Motion Spikes2017In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 155, 354-369 p.Article in journal (Refereed)
    Abstract [en]

    We propose a voxel-wise general linear model with autoregressive noise and heteroscedastic noise innovations (GLMH) for analyzing functional magnetic resonance imaging (fMRI) data. The model is analyzed from a Bayesian perspective and has the benefit of automatically down-weighting time points close to motion spikes in a data-driven manner. We develop a highly efficient Markov Chain Monte Carlo (MCMC) algorithm that allows for Bayesian variable selection among the regressors to model both the mean (i.e., the design matrix) and variance. This makes it possible to include a broad range of explanatory variables in both the mean and variance (e.g., time trends, activation stimuli, head motion parameters and their temporal derivatives), and to compute the posterior probability of inclusion from the MCMC output. Variable selection is also applied to the lags in the autoregressive noise process, making it possible to infer the lag order from the data simultaneously with all other model parameters. We use both simulated data and real fMRI data from OpenfMRI to illustrate the importance of proper modeling of heteroscedasticity in fMRI data analysis. Our results show that the GLMH tends to detect more brain activity, compared to its homoscedastic counterpart, by allowing the variance to change over time depending on the degree of head motion.

    The full text will be freely available from 2018-05-01 10:46
  • 3.
    Corander, Jukka
    et al.
    Department of Mathematics, Åbo Akademi University, Åbo, Finland.
    Ekdahl, Magnus
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    Koski, Timo
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    A bayesian random fragment insertion model for de novo detection of DNA regulatory binding regions2007Manuscript (preprint) (Other academic)
    Abstract [en]

    Identification of regulatory binding motifs within DNA sequences is a commonly occurring problem in computationnl bioinformatics. A wide variety of statistical approaches have been proposed in the literature to either scan for previously known motif types or to attempt de novo identification of a fixed number (typically one) of putative motifs. Most approaches assume the existence of reliable biodatabasc information to build probabilistic a priori description of the motif classes. No method has been previously proposed for finding the number of putative de novo motif types and their positions within a set of DNA sequences. As the number of sequenced genomes from a wide variety of organisms is constantly increasing, there is a clear need for such methods. Here we introduce a Bayesian unsupervised approach for this purpose by using recent advances in the theory of predictive classification and Markov chain Monte Carlo computation. Our modelling framework enables formal statistical inference in a large-scale sequence screening and we illustrate it by a set of examples.

  • 4.
    Roy, Chandan
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Science & Engineering.
    A biologically based machine learning approach to tropical cyclone intensity forecastingManuscript (preprint) (Other academic)
    Abstract [en]

    A biologically based ANN using four hierarchical levels, is trained and tested using temporal sequences of 2D inputs to forecast Tropical Cyclone (TC) intensity12, and 24 hours ahead in the Atlantic basin. We use five parallel input layers to feed infrared, ocean heat content, sea-level pressure, wind direction and wind speed images into the network. Forecasts are produced in the Saffir-Simpson hurricane intensity scale and are compared to the observed wind speeds in the TC best track data on two separate test datasets for validation. Forecasting accuracy is more than 95% for the test dataset containing temporal continuations of the TC lifecycle time-step images that are excluded from training, whereas, forecasting accuracy is between 30% and 55%, when images of a novel TC are used for testing. This result reveals that biologically inspired ANNs have a potential to be further developed into an effective TC intensity forecasting technique.

  • 5.
    Evangelista, Pietro
    et al.
    IRAT-CNR and Department of Management and Engineering, University of Naples Federico II, Italy.
    Huge-Brodin, Maria
    Linköping University, Department of Management and Engineering, Logistics Management. Linköping University, The Institute of Technology.
    Isaksson, Karin
    Linköping University, Department of Management and Engineering, Logistics Management. Linköping University, The Institute of Technology.
    Sweeney, Edward
    National Institute for Transport and Logistics, Dublin Institute of Technology, Ireland.
    A case study investigation on purchasing green transport and logistics services2012In: Purchasing & Supply Management in a Changing World: IPSERA 2012 Conference Proceedings / [ed] Esposito, E., Evangelista, P., Pastore, G., Raffa, M., Napoli, Italia: Edizioni Scientifiche Italiane , 2012, WP17-1-WP17-13 p.Conference paper (Refereed)
    Abstract [en]

    n the context of green supply chain management, green purchasing has received increased attention over the past decade and the strategic importance of introducing green aspects into purchasing practices has been recognised. Despite this growing importance, little has been written in relation to purchasing green transport and logistics services. Considering the strong environmental impact associated with transport and logistics activities, much remains to be learned concerning buyer’s practices when sourcing more sustainable services from third party logistics companies (3PLs). The aim of this paper is to explore practices of buying green transport and logistics services in three different European countries (Italy, Ireland and Sweden) using a multiple case study research approach. The paper analyses how general environmental company ambitions and environmental purchasing practices are reflected when green transport and logistics services are purchased. The results of the paper indicate that while the case companies show a relatively high concern of green issues at company level, a lower importance is attributed to green issues at the purchasing function level. When green concerns in purchasing transport and logistics services are analysed the level of importance decrease dramatically. It emerges a conflicting attitude among the overall company level and the purchasing of transport and logistics services. This suggests that there is the potential for improvements especially in the area of green collaboration in buyer and supplier relationships. 

  • 6.
    Strand, Joel
    et al.
    Linköping University, Department of Management and Engineering, Production Economics.
    Strandänger, Louise
    Linköping University, Department of Management and Engineering, Production Economics.
    A case study on how an e-tailer can use a multiple criteria ABC analysis to identify risk in the selection of suppliers2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Purpose – The purpose of this master thesis is to explore how an e-tailer selling bulky items can use a multiple criteria ABC analysis to make its purchasing process more effective, while balancing richness and reach, with the performance measurements of profitability, total asset turnover and inventory turnover. The purpose will be accomplished through a single case study on an e-tailer active on the Swedish furniture and home furnishing market.

    Methodology – This thesis applies a multiple criteria ABC-analysis to a single case study. The approach is semi-deductive as theory is combined with interviews on how to match and adapt theory about inventory control and purchasing with the specific requirements of an e-tailer selling bulky items.

    Findings – This thesis has resulted in a set of recommendations that aim to make the purchasing process of an e-tailer more effective. That is, capital and inventory space will be better allocated to the e-tailer’s more profitable items. Among other things, this thesis shows how dead articles can be identified and how a purchaser can prioritize more profitable articles over less profitable ones when making procurement decisions. The other recommendations are for the e-tailer to investigate the possibilities of decoupling the supply chain by keeping stock at the suppliers’ premises, to match the supplier reliability with their importance in the supply chain, and lastly to explore possibilities of drop shipment. Further, the main finding is that a comparison between the A-, B-, and C-classes and the reliability of the suppliers, highlights a gap and a possible risk. Put differently, the importance of a specific item for the business should be reflected in the choice of supplier and the multiple criteria ABC analysis is the tool to illustrate the importance.

    Keywords – E-commerce, E-tailer, richness, reach, transaction cost, ABC analysis, multiple criteria ABC, MCABC, inventory turnover ratio, supplier selection, purchasing

    Paper type – Masters thesis

  • 7.
    Tagesson (Sonesson), Sofi
    et al.
    Linköping University, Department of Medical and Health Sciences, Physiotherapy. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Öberg, Birgitta
    Linköping University, Department of Medical and Health Sciences, Physiotherapy. Linköping University, Faculty of Health Sciences.
    Good, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Kvist, Joanna
    Linköping University, Department of Medical and Health Sciences, Physiotherapy. Linköping University, Faculty of Health Sciences.
    A comprehensive rehabilitation program with quadriceps strengthening in closed versus open kinetic chain in patients with anterior cruciate ligament deficiency: a randomized clinical trial evaluating dynamic tibial translation and muscle function2008In: American Journal of Sports Medicine, ISSN 0363-5465, E-ISSN 1552-3365, Vol. 36, no 2, 298-307 p.Article in journal (Refereed)
    Abstract [en]

    Background: There is no consensus regarding the optimal rehabilitation regimen for increasing quadriceps strength after anterior cruciate ligament (ACL) injury.

    Hypothesis: A comprehensive rehabilitation program supplemented with quadriceps strengthening in open kinetic chain (OKC) exercise will increase quadriceps strength and improve knee function without increasing static or dynamic sagittal tibial translation, compared with the same comprehensive rehabilitation program supplemented with quadriceps strengthening in closed kinetic chain (CKC) exercise, in patients with acute ACL deficiency.

    Study Design: Randomized controlled trial; Level of evidence, 1.

    Methods: Forty-two patients were tested a mean of 43 days (range, 20–96 days) after an ACL injury. Patients were randomized to rehabilitation with CKC quadriceps strengthening (11 men and 9 women) or OKC quadriceps strengthening (13 men and 9 women). Aside from these quadriceps exercises, the 2 rehabilitation programs were identical. Patients were assessed after 4 months of rehabilitation. Sagittal static translation and dynamic tibial translation were evaluated with a CA-4000 electrogoniometer. Muscle strength, jump performance, and muscle activation were also assessed. Functional outcome was evaluated by determining the Lysholm score and the Knee Injury and Osteoarthritis Outcome Score.

    Results: There were no group differences in static or dynamic translation after rehabilitation. The OKC group had significantly greater isokinetic quadriceps strength after rehabilitation (P = .009). The hamstring strength, performance on the 1-repetition-maximum squat test, muscle activation, jump performance, and functional outcome did not differ between groups.

    Conclusions: Rehabilitation with OKC quadriceps exercise led to significantly greater quadriceps strength compared with rehabilitation with CKC quadriceps exercise. Hamstring strength, static and dynamic translation, and functional outcome were similar between groups. Patients with ACL deficiency may need OKC quadriceps strengthening to regain good muscle torque.

  • 8.
    Setijono, Djoko
    Linköping University, Department of Management and Engineering, Quality Technology and Management . Linköping University, The Institute of Technology.
    A conceptual framework for managing the performance of construction supply chain2009In: International Journal of Productivity and Quality Management, ISSN 1746-6474, Vol. 5, no 1, 1-20 p.Article in journal (Refereed)
    Abstract [en]

    This paper conceptualises four different states of the construction supply chain (fragmented supply markets, process integration, work clusters, and pools of suppliers) as the result of intersecting two strategic dimensions: industrial 'modes' (i.e. from project to process) and the extent of integration in which partnership exists (i.e. from less to highly integrated supply chain). Improvement methodologies such as TQM and lean thinking provide management philosophy, methods and tools to improve the performance of the construction supply chain towards its 'ideal' practice (value creation). Since benchmarking is an important mechanism for managing performance in the construction industry, the actors in a construction supply chain need to identify and develop relevant value-related (performance) measures and their impacts on gaining/maintaining partners' trust and their willingness to collaborate.

  • 9.
    Lakemond, Nicolette
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Project management, Innovations and Entrepreneurship .
    van Echtelt, F
    Wynstra, F
    A Configuration Typology for Involving Purchasing Specialists in Product Development2001In: ICFAI Journal of supply chain management, ISSN 0972-9267, Vol. 37, no 4, 11-27 p.Article in journal (Refereed)
    Abstract [en]

      

  • 10.
    Daneva, Maria
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    Lindberg, Per Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    A Conjugate Direction Frank-Wolfe Method with Applications to the Traffic Assignment Problem2003In: Operations Research Proceedings 2002: Selected Papers of the International Conference on Operations Research (SOR 2002), Klagenfurt, September 2-5, 2002" / [ed] Leopold-Wildburger, U, Springer , 2003, -550 p.Chapter in book (Other academic)
    Abstract [en]

    This proceedings volume contains a selection of papers presented at the International Conference on Operations Research (SOR 2002).The contributions cover the broad interdisciplinary spectrum of Operations Research and present recent advances in theory, development of methods, and applications in practice. Subjects covered are Production, Logistics and Supply Chain Production, Marketing and Data Analysis, Transportation and Traffic, Scheduling and Project Management, Telecommunication and Information Technology, Energy and Environment, Public Economy, Health, Agriculture, Education, Banking, Finance, Insurance, Risk Management, Continuous Optimization, Discrete and Combinatorial Optimization, Stochastic and Dynamic Programming, Simulation, Control Theory, Systems Dynamics, Dynamic Games, Game Theory, Auctioning and Bidding, Experimental Economics, Econometrics, Statistics and Mathematical Economics, Fuzzy Logic, Multicriteria Decision Making, Decision Theory.

  • 11.
    Sharifimajd, Babak
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    A Continuum Framework for Modeling the Excitation–Contraction Coupling of Smooth Muscle2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Excitation-contraction coupling of smooth muscle refers to a chain of coupled physiological processes which convert a stimulus to a mechanical response. These processes can be disassociated into ionic transport during cell membrane excitation, activation of myosin light chains, and muscle contraction caused by actin-myosin interaction (filament sliding). This thesis concerns the development of a framework which allows to model the smooth muscle excitation-contraction coupling constitutively by applying the principle of virtual power and dissipation inequality. In doing so, the transport of ions through membrane channels is characterized by an ionic flux and an ionic supply, both governed by an electrochemical potential energy. By letting the Helmholtz free energy to be dependent on the myosin light chain configurations during contraction, the myosin light chain activation process, i.e., myosin phosphorylation, is included. The activation process links the membrane excitation to the filament sliding. A contractile element is presented to replicate the active deformation caused by the filament sliding within the smooth muscle cell. This deformation is coupled to the overall deformation of the muscle tissue by assuming a distinct principal alignment for the contractile elements.

    By employing this framework, an electro-chemo-mechanical model is derived by which the mechanical response of smooth muscle to an electrical stimulus is determined. This model is evaluated by comparing the model response to the experimental isometric stress data obtained from rat uterine smooth muscle tissue. By implementing this model in a finite element program, human uterine contractions during labor are simulated. This simulation determines important clinical factors, e.g., intrauterine pressure and provides the opportunity to investigate the effect of physiological and structural parameters on the uterine contractility.

    Finally, a methodology to accommodate individualized parameters from intrauterine pressure measurements is established. This methodology allows to develop models with potentials of being used clinically to diagnose difficulties during labor and delivery.

    List of papers
    1. A continuum model for skeletal muscle contraction at homogeneous finite deformations
    Open this publication in new window or tab >>A continuum model for skeletal muscle contraction at homogeneous finite deformations
    2013 (English)In: Biomechanics and Modeling in Mechanobiology, ISSN 1617-7959, E-ISSN 1617-7940, Vol. 12, no 5, 965-973 p.Article in journal (Refereed) Published
    Abstract [en]

    The contractile force in skeletal muscle models is commonly postulated to be the isometric force multiplied by a set of experimentally motivated functions which account for the muscle’s active properties. Although both flexible and simple, this approach does not automatically guarantee a thermodynamically consistent behavior. In contrast, the continuum mechanical model proposed herein is derived from fundamental principles in mechanics and guarantees a dissipative behavior. Further, the contractile force is associated with a friction clutch which provides a simple and well-defined macroscopic model for cycling cross-bridges. To show the performance of the model, it is specialized to standard experiments for rabbit tibialis anterior muscle. The results show that the model is able to capture important characteristics of skeletal muscle.

    Place, publisher, year, edition, pages
    Springer, 2013
    Keyword
    Skeletal muscle, Contractile element, Dissipation inequality, Strain-energy function, Continuum model
    National Category
    Other Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-85805 (URN)10.1007/s10237-012-0456-x (DOI)000324378900008 ()
    Funder
    Swedish Research Council
    Available from: 2012-11-28 Created: 2012-11-28 Last updated: 2015-09-02Bibliographically approved
    2. A continuum model for excitation–contraction of smooth muscle under finite deformations
    Open this publication in new window or tab >>A continuum model for excitation–contraction of smooth muscle under finite deformations
    2014 (English)In: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 355, 1-9 p.Article in journal (Refereed) Published
    Abstract [en]

    The main focus in most of continuum based muscle models is the muscle contraction dynamics while other physiological processes governing muscle contraction, e.g., the cell membrane excitation and the activation, are ignored. These latter processes are essential to initiate contraction and to determine the amount of generated force, and by excluding them, the developed model cannot replicate the true behavior of the muscle in question. The aim of this study is to establish a thermodynamically and physiologically consistent framework which allows to model smooth muscle contraction by including cell membrane excitability and kinetics of myosin phosphorylation, along with dynamics of smooth muscle contraction. The model accounts for these processes through a set of coupled dissipative constitutive equations derived by applying the first principles. To show the performance of the derived model, it is evaluated for two different cases: a mechanochemical study of pig taenia coli cells where the excitation process is excluded, and a complete excitation–contraction process of rat myometrium. The results show that the model is able to replicate important aspects of the smooth muscle EC process acceptably.

    Place, publisher, year, edition, pages
    Elsevier, 2014
    Keyword
    Smooth muscle excitation–contraction, Smooth muscle continuum model, The membrane model, Hodgkin-Huxley model, Hai-Murphy model
    National Category
    Other Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-100778 (URN)10.1016/j.jtbi.2014.03.016 (DOI)000337865100001 ()
    Available from: 2013-11-12 Created: 2013-11-12 Last updated: 2015-09-02Bibliographically approved
    3. Simulating uterine contraction by using an electro-chemo-mechanical model
    Open this publication in new window or tab >>Simulating uterine contraction by using an electro-chemo-mechanical model
    2016 (English)In: Biomechanics and Modeling in Mechanobiology, ISSN 1617-7959, E-ISSN 1617-7940, Vol. 15, no 3, 497-510 p.Article in journal (Refereed) Published
    Abstract [en]

    Contractions of uterine smooth muscle cells consist of a chain of physiological processes. These contractions provide the required force to expel the fetus from the uterus. The inclusion of these physiological processes is, therefore, imperative when studying uterine contractions. In this study, an electro-chemo-mechanical model to replicate the excitation, activation, and contraction of uterine smooth muscle cells is developed. The presented modeling strategy enables efficient integration of knowledge about physiological processes at the cellular level to the organ level. The model is implemented in a three-dimensional finite element setting to simulate uterus contraction during labor in response to electrical discharges generated by pacemaker cells and propagated within the myometrium via gap junctions. Important clinical factors, such as uterine electrical activity and intrauterine pressure, are predicted using this simulation. The predictions are in agreement with clinically measured data reported in the literature. A parameter study is also carried out to investigate the impact of physiologically related parameters on the uterine contractility.

    Place, publisher, year, edition, pages
    Springer, 2016
    Keyword
    Excitation-contraction model of uterine smooth muscle; Uterus contraction; Intrauterine pressure; Uterine electrical activity
    National Category
    Applied Mechanics
    Identifiers
    urn:nbn:se:liu:diva-121013 (URN)10.1007/s10237-015-0703-z (DOI)000376014800002 ()26162461 (PubMedID)
    Available from: 2015-09-02 Created: 2015-09-02 Last updated: 2016-06-13Bibliographically approved
    4. Identification of the mechanical parameters for the human uterus in vivo using intrauterine pressure measurements
    Open this publication in new window or tab >>Identification of the mechanical parameters for the human uterus in vivo using intrauterine pressure measurements
    2017 (English)In: International Journal for Numerical Methods in Biomedical Engineering, ISSN 2040-7939, E-ISSN 2040-7947, Vol. 33, no 1, 1-11 p.Article in journal (Refereed) Published
    Abstract [en]

    There are limited experimental data to characterize the mechanical response of human myometrium. A method is presented in this work to identify mechanical parameters describing the active response of human myometrium from the in vivo intrauterine pressure measurements. A finite element model is developed to compute the intrauterine pressure during labor in response to an increase in the intracellular calcium ion concentration within myometrial smooth muscle cells. The finite element model provides the opportunity to tune mechanical parameters in order to fit the computed intrauterine pressure to in vivo measurements. Since the model is computationally expensive, a cheaper meta-model is generated to approximate the model response. By fitting the meta-model response to the in vivo measurements, the parameters used to determine the active response of human myometrial smooth muscle are identified.

    Place, publisher, year, edition, pages
    John Wiley & Sons, 2017
    Keyword
    human uterine smooth muscle mechanics, intrauterine pressure, parameter identification, response surface methodology
    National Category
    Applied Mechanics Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-121014 (URN)10.1002/cnm.2778 (DOI)000393964900001 ()26915913 (PubMedID)2-s2.0-84962638845 (Scopus ID)
    Note

    At the time of the thesis presentation this publication was in status Manuscript.

    Available from: 2015-09-02 Created: 2015-09-02 Last updated: 2017-03-27Bibliographically approved
  • 12.
    Kaijser, Thomas
    Linköping University, Department of Mathematics, Mathematics and Applied Mathematics. Linköping University, Faculty of Science & Engineering.
    A Contraction Theorem for Markov Chains on General State Spaces2015Report (Other academic)
    Abstract [en]

    Let {X(n), n=0,1,2,...} denote a Markov chain on a general state space and let f be a nonnegative function. The purpose of this paper is to present conditions which will imply that f(X(n)) tends to 0 a.s., as n tends to infinity. As an application we obtain a result on "synchronisation for random dynamical systems". At the end of the paper we also present a result on  "convergence in distribution" for random dynamical system on complete, separable, metric spaces, a result, which is a generalisation of  a similar result for random dynamical systems on compact, metric spaces.

  • 13.
    Kaijser, Thomas
    Linköping University, Department of Mathematics, Mathematics and Applied Mathematics. Linköping University, Faculty of Science & Engineering.
    A contraction theorem for Markov chains on general state spaces2017In: Revue Roumaine De Mathématiques Pures Et Appliquées, ISSN 0035-3965, Vol. LXII, no 2Article in journal (Refereed)
    Abstract [en]

    Let {Xn, n = 0, 1, 2, ...} denote a Markov chain on a general state space and let f be a nonnegative function. The purpose of this paper is to present conditions which will imply that f(Xn) tends to 0 a.s., as n tends to infinity. As an application we obtain a result on synchronisation for random dynamical systems. At the end of the paper, we also present a result on convergence in distribution for Markov chains on general state spaces, thereby generalising a similar result for Markov chains on compact metric spaces.

    AMS 2010 Subject Classification: 60J05, 60F15, 60F05.

  • 14.
    Spiegler, Virginia L M
    et al.
    Cardiff University, Wales .
    Naim, Mohamed M
    Cardiff University, Wales .
    Wikner, Joakim
    Linköping University, Department of Management and Engineering, Production Economics. Linköping University, The Institute of Technology.
    A control engineering approach to the assessment of supply chain resilience2012In: International Journal of Production Research, ISSN 0020-7543, E-ISSN 1366-588X, Vol. 50, no 21, 6162-6187 p.Article in journal (Refereed)
    Abstract [en]

    There is no consensus on the supply chain management definition of resilience. To aid in evaluating the dynamic behaviour of such systems we need to establish clearly elucidated performance criteria that encapsulate the attributes of resilience. A literature review establishes the latter as readiness, responsiveness and recovery. We also identify robustness as a necessary condition that would complement resilience. We find that the Integral of the Time Absolute Error (ITAE) is an appropriate control engineering measure of resilience when it is applied to inventory levels and shipment rates. We use the ITAE to evaluate an often used benchmark model of make-to-stock supply chains consisting of three decision parameters. We use both linear and nonlinear forms of the model in our evaluation. Our findings suggest that optimum solutions for resilience do not yield a system that is robust to uncertainties in lead-time. Hence supply chains will experience drastic changes in their resilience performance when lead-time changes.

  • 15.
    Nilsson, Marcus
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Westring, Alexander
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A decision support system for an improved article placement2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Warehouse storage is an important part of a business’ supply chain. This is where articles temporary are stored before they either are carried on to the next step of the production or to be delivered to the customers of the company. The largest part of the stock keeping often devoted to the order picking. Order picking includes the activities that are occurring when an article is being picked from its stored position and is being transported to the next step of the flow of the materials. The most time- consuming part of the order picking process are often the time to pinpoint and to get the hold of an article. This implies quite likely that an enhancement of the productivity could be realized, inter alia, through cut the transport distances. SKF Mekan AB is an industrial corporation whose primary occupation is to manufacture bearing housings. Currently, the business has a flawed inventory for stock keeping. A great many of the articles stored in the inventory, entitled 104C, are placed in regard to their measures, without any thought in regard of how frequently the articles are picked. In addition, the article placement that is used today is outdated, which has resulted in that a lot of articles are lacking a specific placement in the inventory. The purpose of storing articles in the inventory 104C is to cope with fluctuations in the next step of the manufacturing, which is the processing factory. The aim of the study is to find out how the article placement looks in the current situation and how decisions concerning article placement are determined and what issues occurs due to this. A decision support system has been developed which purpose is to give SKF Mekan AB decision basis regarding where the different kinds of articles should be placed to attain an increased efficiency in business’ stock keeping. The decision support system is adaptable to the extent that the user can adjust the parameters that are determining the article placement. The study has been accomplished by means of observations and interviews. With the help of the observations, the layout of the warehouse and the article placement has been mapped out and with the help of the interviews; the results concerning work models and decision-making of article placement has been answered. Through the observations and the interviews appeared that 42.5 % of the stocked pallets were misplaced and that 15.6 % of the stocked pallets lacked a specific placement in the warehouse. This results in that the truck operators has a hard time localizing the pallets, which leads to inefficient labouring. This causes delays in the next step of the supply chain; i. e. the processing factory, meaning the personnel has to wait for the articles to be delivered. With the articles picking frequency and the principle of family grouping as point of reference for the article placement SKF Mekan AB should be able to eliminate non-value adding activities in the supply chain, which should lead to an increased potential of profitability.

  • 16.
    Dolphin, Gunnar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    A designed branched three-helix bundle protein dimer2006In: Journal of the American Chemical Society, ISSN 0002-7863, Vol. 128, no 22, 7287-7290 p.Article in journal (Refereed)
    Abstract [en]

    The ultimate goals of de novo protein design are the construction of novel tertiary structures and functions. Here is presented the design and synthesis of a uniquely branched three-helix bundle that folds into a well-folded dimeric protein. The branching of this protein was performed by the method of native chemical ligation, which provides a chemoselective and stable amide bond between the unprotected fragments. This ligation strategy was possible by the presented facile preparation of a peptide (43 amino acids) with a specific side chain thioester, which is synthesized by general Fmoc solid phase peptide synthesis. From the presented structural analysis, it is seen that the folded protein is present as a stable and highly helical dimer, thus forming a six-helix bundle. This unique tertiary structure, composed of a dimer of three individual a-helices branched together, offers different possibilities for protein engineering, such as metal and cofactor binding sites, as well as for the construction of novel functions. © 2006 American Chemical Society.

  • 17.
    Svärd, Anna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Kastbom, Alf
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Rheumatology in Östergötland.
    Sommarin, Yngve
    EuroDiagnostica AB, Malmö.
    Skogh, Thomas
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Rheumatology in Östergötland.
    A disease-modifying role for mucosal IgA antibodies to citrullinated antigens?2012In: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 71, no Issue suppl. 1, A38-A39 p.Article in journal (Refereed)
    Abstract [en]

    Objective

    The aim of this study was to investigate whether immunoglobulin A (IgA) antibodies to cyclic citrullinated peptides CCP) can be detected in saliva of patients with established heumatoid arthritis (RA) and if it relates to clinical manifestations.

    Methods

    Salivary samples were collected (by ‘passive drooling’) from 63 consecutive patients with established RA at a visit to the rheumatology outpatient clinic (Falun, Sweden), and from 20 healthy persons (hospital staff). The samples were centrifuged and kept frozen at −70°C until analysis. IgA-class anti-CCP antibodies in saliva were analysed by adaptation of commercial ELISA (Immunoscan RA, Euro-Diagnostica AB, Malmo, Sweden) using polyclonal rabbit antihuman α-chain specific antibodies conjugated with horseradish peroxidase(DakoCytomation, Glostrup, Denmark) as secondary antibody. To ensure specificity of the reaction, a corresponding ELISA was set up to analyse IgA antibodies to control antigen(cyclic arginine peptide, CAP), and anti-CCP/anti-CAP ratios were calculated. Also, inhibition studies were performed by preincubation of sera with soluble CCP or CAP. Clinical and laboratory data on disease activity, that is, C reactive protein (CRP), erythrocyte sedimentation rate (ESR), and 28-joint count disease activity score (DAS28) as well as radiological outcome (occurrence or absence of erosions as judged by a radiologist in diagnostic routine) were achieved retrospectively via the patients’ medical records.

    Results

    Background reactivity against CCP was found in virtually all patients and healthy subjects, whereas a positive anti-CCP/anti-CAP ratio (≥1.5) was found in 14 out of 63 RA patients (22%) and in one healthy subject (5%). Salivary IgA-reactivity with CCP was dose-dependently inhibited by soluble CCP (but not with CAP) in sera with anti-CCP/anti- CAP ratios ≥1.5. No IgG-reactivity to CCP was found in saliva, although all patients with salivary IgA anti-CCP tested IgG anti-CCP-positive in serum. Furthermore, less than half of those testing IgA-positive in saliva were IgA anti-CCP positive in serum, strongly arguing against passive leakage of anti-CCP antibodies from blood to saliva. The patients testing positive for salivary IgA antibodies had lower average disease activity measures (CRP, ESR, DAS28) at presentation and fewer developed bony erosions within 6 years after presentation (p=0.043, Fisher’s exact test).

    Conclusion

    Salivary IgA antibodies to citrullinated proteins were found in a subset of IgG anti-CCP positive RA patients. In contrast to their serum counterparts, salivary IgA antibodies may associate with a milder/less destructive disease course. This accords with the notion that secretory IgA antibodies exert anti-inflammatory actions, and that they may be associated with induction of systemic tolerance (oral tolerance). The possible disease-modifying role of mucosal immunity to citrullinated proteins needs further investigation!

                    

                                                                    

  • 18.
    Andersson, Henrik
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A Distribution Chain Management Problem in the Swedish Pulp Industry2006Article in journal (Refereed)
  • 19.
    Tombelli, S
    et al.
    Sez Chim Analit, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, Florence, Italy; Sez Igiene, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, Florence, Italy; Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; .
    Mascini, M
    Sez Chim Analit, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, Florence, Italy; Sez Igiene, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, Florence, Italy; Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; .
    Sacco, C
    Sez Chim Analit, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, Florence, Italy; Sez Igiene, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, Florence, Italy; Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; .
    Turner, APF
    Cranfield University, UK.
    A DNA piezoelectric biosensor assay coupled with a polymerase chain reaction for bacterial toxicity determination in environmental samples2000In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 418, no 1Article in journal (Refereed)
    Abstract [en]

    In this paper, we report the realisation of a DNA piezoelectric biosensor coupled with the polymerase chain reaction (PCR) for the detection of a specific bacterial toxicity factor. Biotinylated 23-mer probes were immobilised on the streptavidin coated gold surface of a quartz crystal; streptavidin was covalently bound to the thiol/dextran modified gold surface. The hybridisation of the immobilised probe with a synthetic oligonucleotide was investigated; the absence of non-specific adsorption was verified using a non-complementary oligonucleotide. Many cycles of measurements can be performed on the same crystal surface by regenerating the single strand with 1 mM HCl. The same hybridisation reaction was then performed using real samples of DNA extracted from bacteria and amplified by PCR. The PCR product was a fragment of a specific gene of Aeromonas hydrophila. The piezoelectric biosensor was able to distinguish samples containing the gene or not; in this way it was possible to determine the pathogenicity of different Aeromonas strains isolated from water, vegetables or human specimens. Experiments with non-specific samples confirmed the absence of adsorption or non-specific effects on the quartz crystal treated with the reported procedure. (C) 2000 Elsevier Science B.V. All rights reserved.

  • 20. Hedman, J.
    et al.
    Albinsson, L.
    Ansell, C.
    Tapper, H.
    Hansson, O.
    Holgersson, S,
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics. Linköping University, Faculty of Health Sciences.
    A fast analysis system for forensic DNA reference samples2008In: Forensic Science International: Genetics, ISSN 1872-4973, Vol. 2, no 3, 184-189 p.Article in journal (Refereed)
    Abstract [en]

    On January 1st, 2006, the Swedish legislation on obtaining DNA reference samples from suspects and the recording of DNA profiles in databases was changed. As a result the number of samples analysed at the Swedish National Laboratory of Forensic Science (SKL) increased from about 4500 in 2005 to more than 25,000 in 2006. To meet this challenge, SKL launched a new analysis system to create an unbroken chain, from sampling to incorporation of a profile in the national DNA database and subsequent automatic generation of digitally signed hit reports. The system integrates logistics, digital data transfer, new functions in LIMS (ForumDNA Version 4, Ida Infront AB) and laboratory automation. Buccal swab samples are secured on a FTA® card attached to an identity form, which is barcoded with a unique sample ID. After sampling, the police officer sends a digital request to SKL. The sample is automatically registered in LIMS and processed on delivery. The resulting DNA profiles are automatically classified according to quality using a custom-made expert system. Building the evaluation around mathematical rules makes it reproducible, standardised and minimises manual work and clerk errors. All samples are run in duplicate and the two profiles are compared within LIMS before incorporation in the database. In the first year of operation, the median time for completion of an analysis was 3 days, measured from delivery of the sample to incorporation of the profile in the national DNA database. In spite of the dramatic increase in the number of reference samples there was no backlog. © 2008 Elsevier Ireland Ltd. All rights reserved.

  • 21.
    Grill, Tomas
    et al.
    Linköping University, Department of Mathematics.
    Östberg, Håkan
    Linköping University, Department of Mathematics.
    A Financial Optimization Approach to Quantitative Analysis of Long Term Government Debt Management in Sweden2003Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Swedish National Debt Office (SNDO) is the Swedish Government’s financial administration. It has several tasks and the main one is to manage the central government’s debt in a way that minimizes the cost with due regard to risk. The debt management problem is to choose currency composition and maturity profile - a problem made difficult because of the many stochastic factors involved.

    The SNDO has created a simulation model to quantitatively analyze different aspects of this problem by evaluating a set of static strategies in a great number of simulated futures. This approach has a number of drawbacks, which might be handled by using a financial optimization approach based on Stochastic Programming.

    The objective of this master’s thesis is thus to apply financial optimization on the Swedish government’s strategic debt management problem, using the SNDO’s simulation model to generate scenarios, and to evaluate this approach against a set of static strategies in fictitious future macroeconomic developments.

    In this report we describe how the SNDO’s simulation model is used along with a clustering algorithm to form future scenarios, which are then used by an optimization model to find an optimal decision regarding the debt management problem.

    Results of the evaluations show that our optimization approach is expected to have a lower average annual real cost, but with somewhat higher risk, than a set of static comparison strategies in a simulated future. These evaluation results are based on a risk preference set by ourselves, since the government has not expressed its risk preference quantitatively. We also conclude that financial optimization is applicable on the government debt management problem, although some work remains before the method can be incorporated into the strategic work of the SNDO.

  • 22.
    Servitja Robert, Maria
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, Faculty of Science & Engineering.
    A First Study on Hidden Markov Models and one Application in Speech Recognition2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Speech is intuitive, fast and easy to generate, but it is hard to index and easy to forget. What is more, listening to speech is slow. Text is easier to store, process and consume, both for computers and for humans, but writing text is slow and requires some intention. In this thesis, we study speech recognition which allows converting speech into text, making it easier both to create and to use information. Our tool of study is Hidden Markov Models which is one of the most important machine learning models in speech and language processing.

    The aim of this thesis is to do a rst study in Hidden Markov Models and understand their importance, particularly in speech recognition. We will go through three fundamental problems that come up naturally with Hidden Markov Models: to compute a likelihood of an observation sequence, to nd an optimal state sequence given an observation sequence and the model, and to adjust the model parameters. A solution to each problem will be given together with an example and the corresponding simulations using MatLab. The main importance lies in the last example, in which a rst approach to speech recognition will be done.

  • 23.
    Wang, Qunzhi
    et al.
    Department of Industrial Engineering and Management Tokyo Institute of Technology.
    Tang, Ou
    Linköping University, The Institute of Technology. Linköping University, Department of Production Economics.
    Tsao, De-bi
    Department of Industrial Engineering and Management Tokyo Institute of Technology.
    A flexible contract strategy in a supply chain with an inflexible production mode2006In: International Journal of Operational Research, ISSN 1745-7645, Vol. 1, no 3, 228-248 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a flexible supply contract with call options model for an inflexible supply chain, where the supplier only has an opportunity to produce one batch due to a long lead-time limitation. In such systems, there are eventually two decision points. At the beginning of the planning horizon, the supplier offers a wholesale price, and possibly also option purchasing and exercising prices. In addition to a firm initial order, the buyer can purchase options to adjust order quantity later. The supplier then determines the production volume. At the second decision point, with updated forecast, the buyer finalises the order quantity by exercising options. We formulate both the buyer's and the supplier's profit functions. Furthermore, we develop explicit expressions to determine the buyer's optimal decisions, and calculate the supplier's optimal decisions numerically. In numerical study, we illustrate that such a flexible contract strategy improves both the buyer's and supplier's profits. Copyright © 2006 Inderscience Enterprises Ltd.

  • 24.
    Liu, Zhenxia
    et al.
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, Faculty of Science & Engineering.
    Yang, Xiangfeng
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, Faculty of Science & Engineering.
    A general large deviation principle for longest runs2016In: Statistics and Probability Letters, ISSN 0167-7152, E-ISSN 1879-2103, Vol. 110, 128-132 p.Article in journal (Refereed)
    Abstract [en]

    In this note we prove a general large deviation principle (LDP) for the longest success run in a sequence of independent Bernoulli trails. This study not only recovers several recently derived LDPs, but also gives new LDPs for the longest success run. The method is based on the Bryc’s inverse Varadhan lemma, which can be intuitively generalized to the longest success run in a two-state (success and failure) Markov chain.

  • 25.
    Kling, Daniel
    et al.
    Norwegian Institute Public Heatlh, Norway; Norwegian University of Life Science, Norway.
    Tillmar, Andreas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. National Board Forens Med, Department Forens Genet and Forens Toxicol, Linkoping, Sweden.
    Egeland, Thore
    Norwegian University of Life Science, Norway; Norwegian Institute Public Heatlh, Norway.
    Mostad, Petter
    Norwegian University of Life Science, Norway; University of Gothenburg, Sweden.
    A general model for likelihood computations of genetic marker data accounting for linkage, linkage disequilibrium, and mutations2015In: International journal of legal medicine (Print), ISSN 0937-9827, E-ISSN 1437-1596, Vol. 129, no 5, 943-954 p.Article in journal (Refereed)
    Abstract [en]

    Several applications necessitate an unbiased determination of relatedness, be it in linkage or association studies or in a forensic setting. An appropriate model to compute the joint probability of some genetic data for a set of persons given some hypothesis about the pedigree structure is then required. The increasing number of markers available through high-density SNP microarray typing and NGS technologies intensifies the demand, where using a large number of markers may lead to biased results due to strong dependencies between closely located loci, both within pedigrees (linkage) and in the population (allelic association or linkage disequilibrium (LD)). We present a new general model, based on a Markov chain for inheritance patterns and another Markov chain for founder allele patterns, the latter allowing us to account for LD. We also demonstrate a specific implementation for X chromosomal markers that allows for computation of likelihoods based on hypotheses of alleged relationships and genetic marker data. The algorithm can simultaneously account for linkage, LD, and mutations. We demonstrate its feasibility using simulated examples. The algorithm is implemented in the software FamLinkX, providing a user-friendly GUI for Windows systems (FamLinkX, as well as further usage instructions, is freely available at www.famlink.se). Our software provides the necessary means to solve cases where no previous implementation exists. In addition, the software has the possibility to perform simulations in order to further study the impact of linkage and LD on computed likelihoods for an arbitrary set of markers.

  • 26.
    Bredström, David
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Rönnqvist, Mikael
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    A genetic algorithm for a pulp distribution problem2003Report (Other academic)
    Abstract [en]

    In this paper we present a genetic algorithm for the pulp distribution problem at a large pulp producer in Scandinavia. The distribution is a major part of the company's supply chain and includes transports with cargo vessels, by train and trucks and storages at terminals in port, at pulp mills and in customer locations. The problem we focus on is to find ship schedules and pulp deliveries in order to minimize the total cost of distribution.

    The genetic algorithm utilizes two linear programming models. The first model optimizes all transport flows given a schedule and the second model approximates the performance of a schedule, measured in the total distribution cost. In the computational experiments we use instances from the real world and compare the results with an exact mixed integer programming approach.

  • 27.
    Mahdavi Mazdeh, Mohammad
    et al.
    Iran University of Science and Technology, Iran.
    Emadikhiav, Mohsen
    Linköping University, Department of Management and Engineering. Linköping University, Faculty of Science & Engineering.
    Parsa, Iman
    Iran University of Science and Technology, Iran.
    A heuristic to solve the dynamic lot sizing problem with supplier selection and quantity discounts2015In: Computers & industrial engineering, ISSN 0360-8352, Vol. 85, 33-43 p.Article in journal (Refereed)
    Abstract [en]

    In the present study, the single-item dynamic lot sizing problem with supplier selection is investigated. The problem is broken down into two different cases. In the first case, quantity discounts are not taken into account; in the second case, incremental and all-unit quantity discounts are considered. Due to the complexity of the problems, a new heuristic is developed, which is based on the Fordyce-Webster Algorithm (Fordyce and Webster, 1984). In order to solve the problem where multiple suppliers are considered, a third dimension is added to the matrices used in the Fordyce-Webster Algorithm. The solutions gained using the proposed algorithm are similar to those of Parsa, Khiav, Mazdeh, and Mehrani (2013) in terms of accuracy and computational time. However, the implementation of matrices makes this method easy to explain in comparison with other heuristics developed for similar problems. (C) 2015 Elsevier Ltd. All rights reserved.

  • 28.
    Bredström, David
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Rönnqvist, Mikael
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Carlsson, Dick
    A hybrid algorithm for a pulp distribution problem2005In: IEEE Intelligent Systems, ISSN 1541-1672, Vol. 20, no 4, 19-25 p.Article in journal (Refereed)
    Abstract [en]

    Distribution is a major factor in the supply chain for Sodra Cell, a leading manufacturer of pulp intended for paper production. Each year, the company transports large quantities of pulp using ships, trains, and trucks; here we focus on scheduling the ships and optimizing deliveries to minimize distribution costs.

  • 29.
    Thunberg, Micael
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Persson, FredrikLinköping University, Department of Science and Technology, Communications and Transport Systems.
    A logistics framework for improving constructionsupply chain performance2013Conference proceedings (editor) (Refereed)
    Abstract [en]

    In recent years, attention has been placed on the logistics activities in constructionprojects in order to reduce total costs. The construction industry is experiencing poorproductivity, resulting from an inability of contractors, subcontractors, and suppliersto cooperate efficiently. Research on logistics in construction lacks a holisticperspective and tends to focus on one activity at a time. This research presents theBuilder’s SCOR model (BSCOR) to be used for logistics improvements inconstruction. The model is based on the Supply Chain Operations Reference Model(SCOR model) covering the total supply chain. The BSCOR model is empiricallyderived through five case studies at different construction sites over a period of fiveyears. This has resulted in a model covering the activities Source, Build, and Plan,that describes the flow of materials to and on the site and how ownership passes to theclient. With the BSCOR model, contractors can map the material and informationflows between supply chain members with standardized process definitions. It is alsopossible to precisely measure the supply chain performance and to know where to putimprovements efforts. The main intention with the BSCOR model is to help theindustry reduce costs and increase productivity.

  • 30.
    Cranford, Ted W.
    et al.
    San Diego State University.
    Krysl, Peter
    University of California San Diego, La Jolla, California.
    Amundin, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
    A New Acoustic Portal into the Odontocete Ear and Vibrational Analysis of the Tympanoperiotic Complex2010In: PLoS ONE, ISSN 1932-6203, Vol. 5, no 8, e11927- p.Article in journal (Refereed)
    Abstract [en]

    Global concern over the possible deleterious effects of noise on marine organisms was catalyzed when toothed whales stranded and died in the presence of high intensity sound. The lack of knowledge about mechanisms of hearing in toothed whales prompted our group to study the anatomy and build a finite element model to simulate sound reception in odontocetes. The primary auditory pathway in toothed whales is an evolutionary novelty, compensating for the impedance mismatch experienced by whale ancestors as they moved from hearing in air to hearing in water. The mechanism by which high-frequency vibrations pass from the low density fats of the lower jaw into the dense bones of the auditory apparatus is a key to understanding odontocete hearing. Here we identify a new acoustic portal into the ear complex, the tympanoperiotic complex (TPC) and a plausible mechanism by which sound is transduced into the bony components. We reveal the intact anatomic geometry using CT scanning, and test functional preconceptions using finite element modeling and vibrational analysis. We show that the mandibular fat bodies bifurcate posteriorly, attaching to the TPC in two distinct locations. The smaller branch is an inconspicuous, previously undescribed channel, a cone-shaped fat body that fits into a thin-walled bony funnel just anterior to the sigmoid process of the TPC. The TPC also contains regions of thin translucent bone that define zones of differential flexibility, enabling the TPC to bend in response to sound pressure, thus providing a mechanism for vibrations to pass through the ossicular chain. The techniques used to discover the new acoustic portal in toothed whales, provide a means to decipher auditory filtering, beam formation, impedance matching, and transduction. These tools can also be used to address concerns about the potential deleterious effects of high-intensity sound in a broad spectrum of marine organisms, from whales to fish.

  • 31.
    Lanemo Myhrinder, Anna
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology.
    Hellqvist, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology.
    Sidorova, Ekaterina
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Söderberg, Anita
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology.
    Baxendale, Helen
    Infectious Disease & Microbiology Unit, Institute of Child Health, University of London Medical School, London, United Kingdom.
    Dahle, Charlotte
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Willander, Kerstin
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Oncology . Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Haematology UHL.
    Tobin, Gerard
    Department of Genetics and Pathology, Uppsala University, Uppsala, Sweden.
    Bäckman, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology.
    Söderberg, Ola
    Department of Genetics and Pathology, Uppsala University, Uppsala, Sweden.
    Rosenquist, Richard
    Department of Genetics and Pathology, Uppsala University, Uppsala, Sweden.
    Hörkko, Sohvi
    Department of Pharmacology and Toxicology and Biocenter Oulu, University of Oulu, and Clinical Research Center, Oulu University Hospital, Oulu, Finland.
    Rosén, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology.
    A new perspective: molecular motifs on oxidized LDL, apoptotic cells, and bacteria are targets for chronic lymphocytic leukemia antibodies2008In: Blood, ISSN 0006-4971, Vol. 111, no 7, 3838-3848 p.Article in journal (Refereed)
    Abstract [en]

    The restricted immunoglobulin (Ig) repertoire found in B-cell chronic lymphocytic leukemia (CLL) implies a role for antigen(s) in the leukemogenesis. The nature of the antigens has, however, not been characterized, although examples of autoantigens have been demonstrated. We have analyzed a panel of 28 CLL cell lines and primary cultures, producing monoclonal Ig with different Ig heavy-chain variable region gene usage and mutational status, including several complementarity determining region 3 homology subset members. Using mass-spectrometry, immunoassays, or protein macroarrays, we have discovered novel antigens binding to CLL Igs. These antigens included cytoskeletal proteins vimentin, filamin B, and cofilin-1, but also phosphorylcholine-containing antigens (eg, Streptococcus pneumoniae polysaccharides and oxidized low-density lipoprotein [oxLDL]). Additional new antigens identified were cardiolipin and proline-rich acidic protein-1. Remarkably, these antigens represent molecular motifs exposed on apoptotic cells/blebs and bacteria, and several CLL Igs bound to apoptotic Jurkat cells. In conclusion, these intriguing data, showing a limited target structure recognition, indicate that CD5+ CLL B cells are derived from a cell compartment that produces "natural antibodies," which may be instrumental in elimination and scavenging of apoptotic cells and pathogenic bacteria.

  • 32.
    Borgh, Annika
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Ekeroth, Johan
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Petoral Jr., Rodrigo M.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry . Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    A new route to the formation of biomimetic phosphate assemblies on gold: Synthesis and characterization2006In: Journal of Colloid and Interface Science, ISSN 1095-7103, Vol. 295, no 1, 41-49 p.Article in journal (Refereed)
    Abstract [en]

    A biomimetic model system based on long-chain alkanethiols tailored with serine, threonine and tyrosine side-chain groups is created as a platform for the study of phosphorylated amino acids. The phosphorylated analogues are synthesized with protective tert-butyl groups that after assembly on thin polycrystalline gold films are removed in an acidic deprotection solution to form the corresponding phosphate self-assembled monolayers (SAMs). The SAMs are thoroughly characterized with null ellipsometry, contact angle goniometry, infrared reflection–absorption spectroscopy and X-ray photoelectron spectroscopy. The assembly and the subsequent deprotection process are optimized with respect to molecular orientation and chain conformation by varying the incubation time and the exposure time to the deprotection solution. The high quality of the generated SAMs suggests that the present assembly/deprotection approach is an attractive alternative when traditional synthetic routes become demanding because of solubility problems.

  • 33.
    Vitiazeva, Varvara
    et al.
    Karolinska Institute, Sweden .
    Li, Jianjun
    National Research Council Canada, Canada .
    Hood, Derek W.
    MRC Harwell, England .
    Moxon, Richard E.
    University of Oxford Nuffield, England .
    Schweda, Elke
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    A novel branching pattern in the lipopolysaccharide expressed by non-typeable Haemophilus influenzae strain 12322013In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 378, 114-122 p.Article in journal (Refereed)
    Abstract [en]

    We report the novel branching pattern in lipopolysaccharide (LPS) expressed by non-typeable Haemophilus influenzae (NTHi) strain 1232. The strain expressed the beta-D-Glcp-(1 -andgt; 4)-[alpha-D-Galp-(1 -andgt; 4)-beta-D-Galp-(1 -andgt; 7)]-D-alpha-D-Hepp-(1 -andgt; 6)-beta-D-Glcp chain linked to the proximal heptose (HepI) of the conserved triheptosyl inner-core moiety of NTHi LPS: L-alpha-D-HepIIIp-(1 -andgt; 2)-[PEtn -andgt; 6]-L-alpha-D-HepIIp-(1 -andgt; 3)-L-alpha-D-HepIp-(1 -andgt; 5)-[PPEtn -andgt; 4]-alpha-Kdop-(2 -andgt; 6)-lipid A. The structure has been elucidated using NMR spectroscopy, electrospray ionization mass spectrometry (ESI-MS) and capillary electrophoresis coupled to electrospray ionization tandem mass spectrometry (CE-ESI-MSn) on O-deacylated LPS and core oligosaccharide (OS) materials, as well as HPLC-ESI-MSo on permethylated, dephosphorylated OS. It was also found that a tetrasaccharide unit bearing sialic acid [alpha-Neu5Ac-(2 -andgt; 3)-beta-D-Galp-(1 -andgt; 4)-beta-D-GlcNAcp-(1 -andgt; 3)-beta-D-Galp-(1 -andgt;] could substitute O-4 of the beta-D-Glcp linked to HepI. In addition, the distal heptose (HepIII) was substituted by PCho -andgt; 6-beta-D-Galp-(1 -andgt; at the O-2 position.

  • 34.
    Lemak, Alexander
    et al.
    University of Toronto.
    Gutmanas, Aleksandras
    University of Toronto.
    Chitayat, Seth
    University of Toronto.
    Karra, Murthy
    University of Toronto.
    Fares, Christophe
    University of Toronto.
    Sunnerhagen, Maria
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology . Linköping University, The Institute of Technology.
    Arrowsmith, Cheryl H
    University of Toronto.
    A novel strategy for NMR resonance assignment and protein structure determination2011In: JOURNAL OF BIOMOLECULAR NMR, ISSN 0925-2738, Vol. 49, no 1, 27-38 p.Article in journal (Refereed)
    Abstract [en]

    The quality of protein structures determined by nuclear magnetic resonance (NMR) spectroscopy is contingent on the number and quality of experimentally-derived resonance assignments, distance and angular restraints. Two key features of protein NMR data have posed challenges for the routine and automated structure determination of small to medium sized proteins; (1) spectral resolution - especially of crowded nuclear Overhauser effect spectroscopy (NOESY) spectra, and (2) the reliance on a continuous network of weak scalar couplings as part of most common assignment protocols. In order to facilitate NMR structure determination, we developed a semi-automated strategy that utilizes non-uniform sampling (NUS) and multidimensional decomposition (MDD) for optimal data collection and processing of selected, high resolution multidimensional NMR experiments, combined it with an ABACUS protocol for sequential and side chain resonance assignments, and streamlined this procedure to execute structure and refinement calculations in CYANA and CNS, respectively. Two graphical user interfaces (GUIs) were developed to facilitate efficient analysis and compilation of the data and to guide automated structure determination. This integrated method was implemented and refined on over 30 high quality structures of proteins ranging from 5.5 to 16.5 kDa in size.

  • 35.
    Osman, Abdimajid
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Hannestad, Ulf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry.
    A possible ethanol-catalyzed rearrangement of vitamin K-1 detected by gas chromatography/mass spectrometry2008In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, Vol. 22, no 23, 3861-3866 p.Article in journal (Refereed)
    Abstract [en]

    We studied vitamin K-1(20), vitamin K-1(25), and vitamin K, epoxide in n-hexane and ethanol solutions by gas chromatography/mass spectrometry (GC/MS) utilizing a DB-5 MS fused-silica capillary column. In ethanol solutions of K-1, we observed an extra peak eluting from the GC column with somewhat longer retention time than K-1(20). A similar peak following K-1(25) was also found. These peaks were not found in n-hexane solutions of K-1. A close examination of the mass spectra of these peaks indicated that they were vitamin K-1 variants containing a base peak at m/z 225 characteristic of the methylnaphthoquinone ring with a four-carbon side chain. In addition, they contained the molecular ions of K-1(20) and K-1(25), respectively. We conclude that K-1(20) and K-1(25), but not K-1 epoxide, might undergo rearrangements in ethanol involving an intramolecular proton transfer and a shift of the beta,gamma-double bond on the phytyl side chain toward the ring. The conjugation of the phytyl double bond with the quinone ring is probably the driving force of the rearrangement. We emphasize, however, that our conclusion is based only on mass spectral analysis and would require further investigation by other spectroscopic methods.

  • 36.
    Söderberg, Anita
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Akter, Hossain
    Department of Emergency Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden..
    Rosén, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    A protein disulfide isomerase/thioredoxin-1 complex is physically attached to exofacial membrane TNF-receptors: overexpression in chronic lymphocytic leukemia2012In: Antioxidants and Redox Signaling, ISSN 1523-0864, E-ISSN 1557-7716, Vol. 18, no 4, 363-375 p.Article in journal (Refereed)
    Abstract [en]

    Aims: The 3D structures and functions of cysteine-rich receptors such as tumor necrosis factor receptors (TNFRs) are redox-modulated by dithiol–disulfide exchange. TNFR superfamily members participate in growth regulation in B-cell chronic lymphocytic leukemia (CLL), and tissue stromal cells interact with leukemia cells, profoundly affecting their viability via release of redox-active components, including cysteine, thioredoxin-1 (Trx1), and Trx reductase. Trx1 was previously shown to enhance release of TNF, which acts as an autocrine/paracrine growth factor in CLL. The nature of the mechanism is not known, however. Here, we investigated whether Trx1 and protein disulfide isomerase (PDI), a chaperone and Trx-family member, may interact with TNFRs. Results: We found direct physical association between PDI and TNFR1 or TNFR2 by coclustering and affinity isolation. PDI (57 kDa) formed covalent/reduction-sensitive 69-kDa complexes with Trx1 (12 kDa) in a majority of CLL cell samples, detected at low levels only in control B-cells. Functionally, the TNF/TNFR signaling via the nuclear factor kappa B-driven autocrine loop was disrupted in a dose-dependent fashion by PDI-inhibitors bacitracin, anti-PDI, or anti-Trx1 antibodies, resulting in reduced viability. PDI was significantly overexpressed in immunoglobulin heavy-chain variable (IGHV) unmutated versus mutated CLL (p=0.0102), and amplified TNF release was observed in the former group. Innovation: This study points out a previously unrecognized physical and functional association of TNFRs with the redox-active proteins PDI and Trx1. Conclusion: We describe here a new level of TNF regulation, in which membrane TNFRs are redox controlled at the exofacial surface by PDI/Trx1. These findings shed new light on the observed survival benefit in CLL B-cells exerted by TNFR-superfamily ligands and point at potential therapeutic strategies

  • 37.
    Rönnbäck, Åsa
    et al.
    Division of Quality Sciences, Chalmers University of Technology, Göteborg.
    Witell, Lars
    Service Research Center, Karlstad University.
    A review of empirical investigations comparing quality initiatives in manufacturing and service organizations2008In: Managing Service Quality, ISSN 0960-4529, Vol. 18, no 6, 577-593 p.Article in journal (Refereed)
    Abstract [en]

    Purpose – The purpose of this paper is to investigate, by reviewing the literature, the relationship between quality management and business performance with a comparison between manufacturing and service organizations.Design/methodology/approach – This meta-analytic study critically examines the literature and evaluates the business performance implications of adopting quality management principles in manufacturing and service organizations. Altogether, 14 published research studies were identified that focused on the relationship between quality management and business performance with a comparison between manufacturing and service organizations.Findings – The results show several inconsistencies in previous research when it comes to the relationship between quality management and business performance when comparing manufacturing and service organizations. Some of these inconsistencies concern the principles of supplier relationships, leadership commitment and customer orientation. The inconsistencies can be explained by a number of factors: the difference in size of the organizations included in the studies, the cultural aspect and the research design. Regarding consistencies, two quality management principles stand out in several studies as being more central for service organizations: employee management and process orientation.Practical implications – The results can provide guidance for service managers aiming to implement quality management. In addition, the paper provides guidance to researchers about methodological issues so that future research can provide more reliable and valid results.Originality/value – The paper provides a critical review of previous research on what principles of quality management should be adopted in a service organization.

  • 38.
    Vesterbacka, Mark
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A robust differential scan flip-flop1999In: Proc. 1999 IEEE Int. Symp. on Circuits and Systems, ISCAS'99, 1999, I-334-I-337 p.Conference paper (Refereed)
    Abstract [en]

    A flip-flop is proposed that is robust against smooth clock edges. This robustness simplifies the design of the clock net in large integrated circuits and lowers the power consumed in the clock driver compared to flip-flops needing sharper clock edges. The proposed flip-flop is realized using 20 MOSFETs and uses a single phase clock. It includes a multiplexer circuit at the input that is useful in a scan test. The flip-flop is semi-static in the sense that the master latch is static while the slave latch is dynamic. This allows the clock to be in the low state for an indefinitely long period, while the period of the high state is limited due to charge leakage. Therefore another circuit is also proposed that limits the pulse width of the clock. The use of this circuit enables design of a scan chain that can be clocked with an arbitrarily low frequency.

  • 39.
    Lindsten, Fredrik
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Schön, Thomas B.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Jordan, Michael I.
    University of California, Berkeley, USA.
    A Semiparametric Bayesian Approach to Wiener System Identification2012In: Proceedings of the 16th IFAC Symposium on System Identification, 2012, 1137-1142 p.Conference paper (Refereed)
    Abstract [en]

    We consider a semiparametric, i.e. a mixed parametric/nonparametric, model of a Wiener system. We use a state-space model for the linear dynamical system and a nonparametric Gaussian process (GP) model for the static nonlinearity. The GP model is a flexible model that can describe different types of nonlinearities while avoiding making strong assumptions such as monotonicity. We derive an inferential method based on recent advances in Monte Carlo statistical methods, known as Particle Markov Chain Monte Carlo (PMCMC). The idea underlying PMCMC is to use a particle filter (PF) to generate a sample state trajectory in a Markov chain Monte Carlo sampler. We use a recently proposed PMCMC sampler, denoted particle Gibbs with backward simulation, which has been shown to be efficient even when we use very few particles in the PF. The resulting method is used in a simulation study to identify two different Wiener systems with non-invertible nonlinearities.

  • 40.
    Lindsten, Fredrik
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Schön, Thomas
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Jordan, Michael I.
    University of California, Berkeley, USA.
    A Semiparametric Bayesian Approach to Wiener System Identification2011Report (Other academic)
    Abstract [en]

    We consider a semiparametric, i.e. a mixed parametric/nonparametric, model of a Wiener system. We use a state-space model for the linear dynamical system and a nonparametric Gaussian process (GP) model for the static nonlinearity. The GP model is a flexible model that can describe different types of nonlinearities while avoiding making strong assumptions such as monotonicity. We derive an inferential method based on recent advances in Monte Carlo statistical methods, known as Particle Markov Chain Monte Carlo (PMCMC). The idea underlying PMCMC is to use a particle filter (PF) to generate a sample state trajectory in a Markov chain Monte Carlo sampler. We use a recently proposed PMCMC sampler, denoted particle Gibbs with backward simulation, which has been shown to be efficient even when we use very few particles in the PF. The resulting method is used in a simulation study to identify two different Wiener systems with non-invertible nonlinearities.

  • 41.
    Barata, J.
    et al.
    Universidade Nova de Lisboa /UNINOVA, Quinta da Torre, 2829-516, Caparica, Portugal .
    Ribeiro, Luis
    Universidade Nova de Lisboa /UNINOVA, Quinta da Torre, 2829-516, Caparica, Portugal.
    Colombo, A-W
    P&T/H6O HUB, Schneider Electric GmbH, Steinheimer Straße 117, 63500, Seligenstadt, Germany.
    A Service-oriented Shop Floor to Support Collaboration in Manufacturing Networks2010In: Artificial Intelligence Techniques for Networked Manufacturing Enterprises Management / [ed] Lyes Benyoucef and Bernard Grabot, Springer London, 2010, 483-503 p.Chapter in book (Refereed)
    Abstract [en]

    The present work addresses the problem of shop-floor agility, presenting it as the fundamental cornerstone for true agility and responsiveness of an enterprise willing to participate in highly dynamic collaborative organizations and supply chains. Clearly, as the economic climate toughens, the exploration of the increasingly volatile business opportunities requires such complex organizations. The feasibility of the architecture proposed is demonstrated in a pilot implementation in a near-real shop-floor. Emerging web standards such as the device profile for web services were used to guarantee cross-layer/abstraction interoperability ensuring that the shop-floor reacts positively to adjustments in the supply chain.

  • 42.
    Sakano, S
    et al.
    Karolinska Institutet.
    Kumar, R
    Karolinska Institutet.
    Larsson, Per C M
    Karolinska Institutet.
    Onelov, E
    Karolinska Institutet.
    Adolfsson, J
    Karolinska Hospital.
    Steinbeck, G
    Karolinska Institutet.
    Hemminki, K
    Karolinska Institutet.
    A single-nucleotide polymorphism in the XPG gene, and tumour stage, grade, and clinical course in patients with nonmuscle-invasive neoplasms of the urinary bladder2006In: BJU International, ISSN 1464-4096, E-ISSN 1464-410X, Vol. 97, no 4, 847-851 p.Article in journal (Refereed)
    Abstract [en]

    To evaluate whether the single nucleotide polymorphism (SNP), Asp1104His (G3507C), in the XPG gene affects malignant phenotypes of nonmuscle-invasive urinary bladder neoplasms (NIBN), by investigating associations between the SNP and clinicopathological variables in patients with NIBN.

    PATIENTS AND METHODS

    The 233 patients constituted newly diagnosed cases of primary NIBN in the Stockholm area. The Asp1104His polymorphism in the XPG gene was genotyped using a polymerase chain reaction-restriction fragment length polymorphism technique.

    RESULTS

    The GC + CC genotypes were more frequent in stage pT1 tumours at initial diagnosis than pTa (odds ratio 1.9, 95% confidence interval 1.0–3.5, P = 0.048). The difference was larger in the young group (4.6, 1.9–11.8, P = 0.001). In the young group, the GC + CC genotypes were significantly more frequent in high-grade than in low-grade tumours (3.1, 1.5–6.8, P = 0.004) whereas in the older group the genotypes were less frequent in high-grade tumours (0.3, 0.1–0.7, P = 0.007). The XPG genotypes were not associated with tumour recurrence, stage progression or survival.

    CONCLUSION

    These results suggest that the SNP in the XPG gene might be related to tumour invasiveness in NIBN.

  • 43.
    Löbus, Jörg-Uwe
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    A Stationary Fleming-Viot type Brownian particle system2009In: Mathematische Zeitschrift, ISSN 0025-5874, E-ISSN 1432-1823, Vol. 263, no 3, 541-581 p.Article in journal (Refereed)
    Abstract [en]

    We consider a system {X(1),...,X(N)} of N particles in a bounded d-dimensional domain D. During periods in which none of the particles X(1),...,X(N) hit the boundary. partial derivative D, the system behaves like N independent d-dimensional Brownian motions. When one of the particles hits the boundary partial derivative D, then it instantaneously jumps to the site of one of the remaining N - 1 particles with probability (N - 1)(-1). For the system {X(1),..., X(N)}, the existence of an invariant measure w has been demonstrated in Burdzy et al. [Comm Math Phys 214(3): 679-703, 2000]. We provide a structural formula for this invariant measure w in terms of the invariant measure m of the Markov chain xi which returns the sites the process X := (X(1),...,X(N)) jumps to after hitting the boundary partial derivative D(N). In addition, we characterize the asymptotic behavior of the invariant measure m of xi when N -> infinity. Using the methods of the paper, we provide a rigorous proof of the fact that the stationary empirical measure processes 1/N Sigma(N)(i=1) (delta)X(i) converge weakly as N -> infinity to a deterministic constant motion. This motion is concentrated on the probability measure whose density with respect to the Lebesgue measure is the first eigenfunction of the Dirichlet Laplacian on D. This result can be regarded as a complement to a previous one in Grigorescu and Kang [Stoch Process Appl 110(1): 111 - 143, 2004].

  • 44.
    Tang, Ou
    et al.
    Linköping University, Department of Management and Engineering, Production Economics. Linköping University, The Institute of Technology.
    Zanoni, Simoni
    University of Brescia, Italy.
    Zavanella, Lucio
    University of Brescia, Italy.
    A stochastic single-vendor single-buyer model under a consignment agreement2007In: Advances in Production Management Systems / [ed] Jan Olhager, Fredrik Persson, Springer, 2007, 321-328 p.Conference paper (Refereed)
    Abstract [en]

    In the recent years, companies have begun to strengthen their supply agreements, such as sharing the management of inventories. This type of co-soperation implies that the members of the supply chain share information and arrange a mutual agreement on their performance targets. The increased interest on supply chain topics has attracted researchers’ attention to the problem of co-operation between the buyer and vendor, the two actors directly interacting in the supply mechanism. The present research investigates the way how a particular VMI policy, known as Consignment Stock (CS), may lead to a successful strategy for both buyer and vendor. The previous study [1] developed an analytical model of the CS policy, with reference to the centralised decision and deterministic settings. In order to fully explore the potentiality of CS policy, an extension of the model is proposed in this paper. The results indicate that the CS policy could be a strategic and profitable approach to improve supply chain performance in uncertain environments.

  • 45.
    Sonntag, Dag
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    A Study of Chain Graph Interpretations2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Probabilistic graphical models are today one of the most well used architectures for modelling and reasoning about knowledge with uncertainty. The most widely used subclass of these models is Bayesian networks that has found a wide range of applications both in industry and research. Bayesian networks do however have a major limitation which is that only asymmetric relationships, namely cause and eect relationships, can be modelled between its variables. A class of probabilistic graphical models that has tried to solve this shortcoming is chain graphs. It is achieved by including two types of edges in the models, representing both symmetric and asymmetric relationships between the connected variables. This allows for a wider range of independence models to be modelled. Depending on how the second edge is interpreted this has also given rise to dierent chain graph interpretations.

    Although chain graphs were first presented in the late eighties the field has been relatively dormant and most research has been focused on Bayesian networks. This was until recently when chain graphs got renewed interest. The research on chain graphs has thereafter extended many of the ideas from Bayesian networks and in this thesis we study what this new surge of research has been focused on and what results have been achieved. Moreover we do also discuss what areas that we think are most important to focus on in further research.

    List of papers
    1. Chain Graphs and Gene Networks
    Open this publication in new window or tab >>Chain Graphs and Gene Networks
    2015 (English)In: Foundations of Biomedical Knowledge Representation: Methods and Applications / [ed] Arjen Hommersom and Peter J.F. Lucas, Springer, 2015, 159-178 p.Chapter in book (Refereed)
    Abstract [en]

    Chain graphs are graphs with possibly directed and undirected edges, and no semidirected cycle. They have been extensively studied as a formalism to represent probabilistic independence models, because they can model symmetric and asymmetric relationships between random variables. This allows chain graphs to represent a wider range of systems than Bayesian networks. This in turn allows for a more correct representation of systems that may contain both causal and non-causal relationships between its variables, like for example biological systems. In this chapter we give an overview of how to use chain graphs and what research exists on them today. We also give examples on how chain graphs can be used to model advanced systems, that are not well understood, such as gene networks.

    Place, publisher, year, edition, pages
    Springer, 2015
    Series
    Lecture Notes in Artificial Intelligence, ISSN 0302-9743 ; 9521
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-105813 (URN)10.1007/978-3-319-28007-3_10 (DOI)978-3-319-28006-6 (ISBN)978-3-319-28007-3 (ISBN)
    Note

    The previous status of this article was Manuscript.

    Available from: 2014-04-08 Created: 2014-04-08 Last updated: 2016-03-29Bibliographically approved
    2. Chain Graph Interpretations and Their Relations, Extended Version
    Open this publication in new window or tab >>Chain Graph Interpretations and Their Relations, Extended Version
    2013 (English)In: Proceedings of the 12th European Conference, ECSQARU 2013, Utrecht, The Netherlands, July 8-10, 2013 / [ed] Linda C. van der Gaag, Springer Berlin/Heidelberg, 2013, 510-521 p.Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper deals with different chain graph interpretations and the relations between them in terms of representable independence models. Specifically, we study the Lauritzen-Wermuth-Frydenberg, Andersson-Madigan-Perlman and multivariate regression interpretations and present the necessary and sufficient conditions for when a chain graph of one interpretation can be perfectly translated into a chain graph of another interpretation. Moreover, we also present a feasible split for the Andersson-Madigan-Perlman interpretation with similar features as the feasible splits presented for the other two interpretations.

    Place, publisher, year, edition, pages
    Springer Berlin/Heidelberg, 2013
    Series
    Lecture Notes in Computer Science, ISSN 0302-9743 (print), 1611-3349 (online) ; Vol. 7958
    Keyword
    Chain Graphs, Lauritzen-Wermuth-Frydenberg interpretation, Andersson-Madigan-Perlman interpretation, multivariate regression interpretation
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-105814 (URN)10.1007/978-3-642-39091-3_43 (DOI)978-3-642-39090-6 (ISBN)978-3-642-39091-3 (ISBN)
    Conference
    The 12th European Conference on Symbolic and Quantitative Approaches to Reasoning with Uncertainty July 7th -10th, Utrecht, The Netherlands
    Note

    Awarded best student paper award at ECSQARU 2013.

    Available from: 2014-04-08 Created: 2014-04-08 Last updated: 2015-05-28Bibliographically approved
    3. Approximate Counting of Graphical Models Via MCMC Revisited
    Open this publication in new window or tab >>Approximate Counting of Graphical Models Via MCMC Revisited
    2015 (English)In: International Journal of Intelligent Systems, ISSN 0884-8173, E-ISSN 1098-111X, Vol. 30, no 3, 384-420 p.Article in journal (Refereed) Published
    Abstract [en]

    We apply MCMC sampling to approximately calculate some quantities, and discuss their implications for learning directed and acyclic graphs (DAGs) from data. Specifically, we calculate the approximate ratio of essential graphs (EGs) to DAGs for up to 31 nodes. Our ratios suggest that the average Markov equivalence class is small. We show that a large majority of the classes seem to have a size that is close to the average size. This suggests that one should not expect more than a moderate gain in efficiency when searching the space of EGs instead of the space of DAGs. We also calculate the approximate ratio of connected EGs to connected DAGs, of connected EGs to EGs, and of connected DAGs to DAGs. These new ratios are interesting because, as we will see, they suggest that some conjectures that appear in the literature do not hold. Furthermore, we prove that the latter ratio is asymptotically 1.

    Finally, we calculate the approximate ratio of EGs to largest chain graphs for up to 25 nodes. Our ratios suggest that Lauritzen-Wermuth-Frydenberg chain graphs are considerably more expressive than DAGs. We also report similar approximate ratios and conclusions for multivariate regression chain graphs.

    Place, publisher, year, edition, pages
    Wiley-Blackwell, 2015
    Keyword
    MCMC sampling, Bayesian networks, Chain graphs, Lauritzen-Wermuth-Frydenberg interpretation, Multivariate regression interpretation
    National Category
    Computer and Information Science
    Identifiers
    urn:nbn:se:liu:diva-105815 (URN)10.1002/int.21704 (DOI)000348308600008 ()
    Note

    This work is funded by the Center for Industrial Information Technology (CENIIT) and a so-called career contract at Linkoping University, by the Swedish Research Council (ref. 2010-4808), and by FEDER funds and the Spanish Government (MICINN) through the projects TIN2010-20900-C04-03 and TIN2010-20900-C04-01.

    Available from: 2014-04-08 Created: 2014-04-08 Last updated: 2016-03-29Bibliographically approved
    4. Learning Multivariate Regression Chain Graphs under Faithfulness
    Open this publication in new window or tab >>Learning Multivariate Regression Chain Graphs under Faithfulness
    2012 (English)In: Proceedings of the 6th European Workshop on Probabilistic Graphical Models, Granada (Spain), 19-21 September, 2012 / [ed] Andrés Cano, Manuel Gémez.-Olmedo and Thomas D. Nielsen, 2012, 299-306 p.Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper deals with multivariate regression chain graphs, which were introduced by Cox and Wermuth (1993, 1996) to represent linear causal models with correlated errors. Specifically, we present a constraint based algorithm for learning a chain graph a given probability distribution is faithful to. We also show that for each Markov equivalence class of multivariate regression chain graphs there exists a set of chain graphs with a unique minimal set of lines. Finally, we show that this set of lines can be identified from any member of the class by repeatedly splitting its connectivity components according to certain conditions.

    Keyword
    Chain Graph, Multivariate Regression Chain Graph, Learning, Bidirected Graph
    National Category
    Computer Systems
    Identifiers
    urn:nbn:se:liu:diva-80306 (URN)978-84-15536-57-4 (ISBN)
    Conference
    Sixth European Workshop on Probabilistic Graphical Models (PGM 2012), 19-21 September 2012, Granada, Spain
    Available from: 2012-08-23 Created: 2012-08-23 Last updated: 2016-07-01Bibliographically approved
    5. An inclusion optimal algorithm for chain graph structure learning: with supplement
    Open this publication in new window or tab >>An inclusion optimal algorithm for chain graph structure learning: with supplement
    2014 (English)In: Proceedings of the 17th International Conference on Arti-cial Intelligence and Statistics, 2014, 778-786 p.Conference paper, Published paper (Other academic)
    Abstract [en]

    This paper presents and proves an extension of Meek’s conjecture to chain graphs under the Lauritzen-Wermuth-Frydenberg interpretation. The proof of the conjecture leads to the development of a structure learning algorithm that finds an inclusion optimal chain graph for any given probability distribution satisfying the composition property. Finally, the new algorithm is experimentally evaluated.

    Series
    JMLR Workshop and Conference Proceedings, Vol. 33
    Keyword
    Chain Graph, Lauritzen-Wermuth-Frydenberg interpretation, Learning
    National Category
    Computer Systems
    Identifiers
    urn:nbn:se:liu:diva-105816 (URN)
    Conference
    17th International Conference on Artificial Intelligence and Statistics April 22-25, 2014, Reykjavik, Iceland
    Available from: 2014-04-08 Created: 2014-04-08 Last updated: 2016-03-29Bibliographically approved
  • 46.
    Martinsen, Uni
    Linköping University, Department of Management and Engineering, Logistics Management. Linköping University, The Institute of Technology.
    A Study of Environmental and Other Sustainable Activities in supply Chain Relationships at Clas Ohlson2013Report (Other academic)
    Abstract [en]

    This report is the result of a case study conducted at the Swedish retail company Clas Ohlson. The study has been conducted as one step in the PhD process of the author of this report and is financed by the Swedish Energy Agency (Energimyndigheten). In this first chapter, some background information to the case study is given: the aim of the study, the rationale behind choosing Clas Ohlson as the case company and data collection methods. Finally, the structure of the remaining parts of the report is presented.

    The aim of this case study is to illustrate how environmental work can be conducted in different types of supply chain relationships, seen from the perspective of one focal shipper in a supply chain. The relationships include both upstream (such as suppliers and inbound logistics service providers) and downstream (such as outbound logistics service providers and stores in a city logistics context) parts of the supply chain. As these examples illustrate, the supply chain relationships can include shippers as well as logistics service providers (LSPs).

  • 47.
    Johansson, Anders
    et al.
    Linköping University, Department of Management and Engineering. Linköping University, The Institute of Technology.
    Jonsson, Seth
    Linköping University, Department of Management and Engineering, Logistics Management. Linköping University, The Institute of Technology.
    A supply chain view on electronic commerce impact on value, relations and loyalty: field survey e-B2B project2003Book (Refereed)
  • 48. Vijayalekshmi, S.
    et al.
    George, S.K.
    Department of Chemistry, Umeå University, 412 527 Umeå, Sweden.
    Andersson, L.K.
    Department of Chemistry, Organic Chemistry, Göteborg University, 412 96 Göteborg, Sweden.
    Kihlberg, J.
    Department of Chemistry, Umeå University, 412 527 Umeå, Sweden.
    Baltzer, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    A surface exposed O-linked galactose residue destabilises the structure of a folded helix-loop-helix dimer2003In: Organic and biomolecular chemistry, ISSN 1477-0520, Vol. 1, no 14, 2455-2460 p.Article in journal (Refereed)
    Abstract [en]

    A 42-residue glycopeptide Tn-15 and the corresponding reference polypeptide Thr-15 were designed and synthesized to provide a model system for the study of how glycosylation affects the stability of a molten globule-like protein. Tn-15 and Thr-15 fold into hairpin helix-loop-helix motifs that dimerise to form four-helix bundles and the only difference between the sequences is that Tn-15 carries an O-linked N-acetylgalactosamine residue at the side chain of threonine-15 whereas the sequence Thr-15 is unglycosylated. An analysis of the mean residue ellipticities at 222 nm of the two polypeptides and of the a-H chemical shift deviations from random coil values showed that glycosylation reduced the helical content of the polypeptides and increased the dissociation constant of the helix-loop-helix dimer to form monomers. The pH dependencies of the helical content of Tn-15 and Thr-15 differed as that of Thr-15 was largely unaffected by pH in the range from pH 4 to pH 10, whereas Tn-15 lost almost half of the helical content at pH 4 upon raising the pH to 10. No single amino acid residue was found to ionize in a way that could explain the observed pH dependence of Tn-15. The temperature dependence of the mean residue ellipticity of Tn-15 revealed a surprising decrease in helicity at 278 K in comparison with that at 293 K, reminiscent of cold denaturation, that was not observed for the reference four-helix bundle Thr-15.

  • 49.
    Sandberg, Erik
    et al.
    Linköping University, Department of Management and Engineering, Logistics & Quality Management. Linköping University, Faculty of Science & Engineering.
    Jafari, Hamid
    Jönköping University, Jönköping, Sweden.
    A systematic review of retail supply chain responsiveness2016Conference paper (Other academic)
  • 50.
    Spiegler, Virginia L. M.
    et al.
    Brunel University, England.
    Naim, Mohamed M.
    Cardiff University, Wales.
    Towill, Denis R.
    Cardiff University, Wales.
    Wikner, Joakim
    Linköping University, Department of Management and Engineering, Production Economics. Linköping University, Faculty of Science & Engineering.
    A technique to develop simplified and linearised models of complex dynamic supply chain systems2016In: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 251, no 3, 888-903 p.Article in journal (Refereed)
    Abstract [en]

    There is a need to identify and categorise different types of nonlinearities that commonly appear in supply chain dynamics models, as well as establishing suitable methods for linearising and analysing each type of nonlinearity. In this paper simplification methods to reduce model complexity and to assist in gaining system dynamics insights are suggested. Hence, an outcome is the development of more accurate simplified linear representations of complex nonlinear supply chain models. We use the highly cited Forrester production-distribution model as a benchmark supply chain system to study nonlinear control structures and apply appropriate analytical control theory methods. We then compare performances of the linearised model with numerical solutions of the original nonlinear model and with other previous research on the same model. Findings suggest that more accurate linear approximations can be found. These simplified and linearised models enhance the understanding of the system dynamics and transient responses, especially for inventory and shipment responses. A systematic method is provided for the rigorous analysis and design of nonlinear supply chain dynamics models, especially when overly simplistic linear relationship assumptions are not possible or appropriate. This is a precursor to robust control system optimisation. (C) 2015 Elsevier B.V. All rights reserved.

1234567 1 - 50 of 1325
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • 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