oru.sePublications
Change search
Refine search result
1234567 1 - 50 of 682
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Abrahamson, Peter
    et al.
    Örebro University, Swedish Business School at Örebro University.
    Bodin, Daniel
    Örebro University, Swedish Business School at Örebro University.
    Behov av stödundervisning i grundskolan: En designbaserad analys av longitudinella data2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 2.
    Adolfsson, Chandra
    Örebro University, Department of Business, Economics, Statistics and Informatics.
    Utvärdering av granskningssystem för SCB:s undersökningar Kortperiodisk Sysselsättningsstatistik och Konjunkturstatistik över Vakanser2007Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I denna studie har undersökningarna Kortperiodisk Sysselsättningsstatistiks (KS) och Konjunkturstatistik över Vakansers (KV) befintliga granskningssystem utvärderats med avseende på hur effektivt det är. Processdata har framställts och analyserats. Resultaten tyder på att många av de inkomna blanketterna med misstänkt felaktiga uppgifter inte rättas upp, utan tvingas igenom trots att granskningssystemet ej accepterade uppgifterna. Det befintliga granskningssystemet har en högre träffsäkerhet avseende KS-undersökningen, men både KS och KV skulle kunnas granskas mer effektivt.

    För att utvärdera det befintliga granskningssystemet ytterligare användes en poängfunktion. Till studien fanns tillgång till både helt ogranskat material och helt granskat material och dessa material användes i poängfunktionen. Det uppräknade ogranskade värdet för varje objekt jämfördes med det uppräknade granskade värdet och ställdes i relation till respektive skattade branschtotal. De poängsatta blanketterna rangordnades sedan. Därefter analyserades materialet för att försöka finna var det skulle vara lämpligt att sätta det tröskelvärde som skulle skilja det material som ”egentligen” skulle ha behövts granskas från det som kunde ha lämnats orört. Att sätta tröskelvärdet är svårt. Här gjordes det godtyckligt utifrån kriterierna att det fel som införs i skattningarna för att allt material inte granskas skulle hållas så lågt som möjligt samt att antalet blanketter som skulle behöva granskas manuellt av produktionsgruppen också skulle hållas så lågt som möjligt. Även här visade det sig att det befintliga granskningssystemet inte är så effektivt som önskas. När resultaten från denna del av utvärderingen analyserades upptäcktes problem som beror på blankettutformningen. Skulle blanketterna ses över och åtgärdas skulle det fel som införs för att allt material inte granskas kunna minskas avsevärt. Genom att minska det införda felet kan tröskelvärdet förmodligen sättas på en ny nivå vilket medför att omfattningen av granskningen skulle minska ytterligare.

    Hur skulle då ett mer effektivt granskningssystem kunna se ut? I den här studien har valet fallit på att testa ”significance editing” på KS-undersökningen, det som på svenska kallas för effektgranskning. En poängfunktion användes även här, denna tilldelar de inkomna blanketterna varsin poäng och dessa poäng rangordnas därefter. Efter att poängen rangordnats bestäms en gräns, ett tröskelvärde, och de blanketter med en poäng som överstiger tröskelvärdet granskas och rättas upp av produktionsgruppen. De blanketter med en poäng som understiger det satta tröskelvärdet rättas inte upp, utan behåller sina originalvärden. Poängfunktionen jämför det inkomna ogranskade, uppräknade, värdet med ett uppräknat ”förväntat” värde och ställer denna differens i relation till den skattade branschtotalen. Svårigheten ligger ofta i att hitta ett bra förväntat värde och detta problem uppstår ideligen i urvalsundersökningar. Tanken med effektgranskning är att omfattningen av granskningen ska minska och den granskning som utförs ska ha effekt på slutresultatet.

    Det var inte lätt att hitta ett bra förväntat värde på den tid som stod till förfogande. Två problem som snabbt upptäcktes var dels att i KS-undersökningen finns inte uträknade säsongs- eller trendfaktorer per variabel. Dessutom byttes en mycket stor del av urvalet ut till kvartal 2 (som denna studie har avgränsats till att behandla). Detta har fått till följd att cirka hälften av objekten i urvalet inte går att följa bakåt i tiden eftersom de inte ingått i urvalet tidigare. I studien har respektive stratums medelvärde använts som förväntat värde. Resultaten visar att det valda förväntade värdet inte skulle ha använts i praktiken, men det fungerar bra i syfte att illustrera hur det i praktiken skulle kunna gå till att införa en mer effektiv granskning.

  • 3.
    Adolfsson, Per
    et al.
    Örebro University, Örebro University School of Business.
    Ivic, Marijo
    Örebro University, Örebro University School of Business.
    Ett försök till att statistiskt modellera matchutfall för fotbollens division 1 för herrar i Sverige2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 4.
    Alam, Md. Moudud
    Örebro University, Swedish Business School at Örebro University.
    Computation and application of likelihood prediction with generalized linear and mixed modelsManuscript (preprint) (Other academic)
    Abstract [en]

    This paper presents the computation of likelihood prediction with the generalized linear and mixed models. The method of likelihood prediction is briefy discussed and approximate formulae are provided to make easy computation of the likelihoodprediction with generalized linear models. For complicated prediction problems, simulation methods are suggested. An R add-in package is accompanied to carryout the computation of the predictive inference with the generalized linear and mixed models. The likelihood prediction is applied to the prediction of the credit defaults using a real data set. Results show that the predictive likelihood can be a useful tool to predict portfolio credit risk.

  • 5.
    Alam, Md. Moudud
    Örebro University, Swedish Business School at Örebro University.
    Feasible computation of generalized linear mixed models with application to credit risk modelling2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with developing and testing feasible computational procedures to facilitate the estimation of and carry out the prediction with the generalized linear mixed model (GLMM) with a scope of applying them to large data sets. The work of this thesis is motivated from an issue arising incredit risk modelling. We have access to a huge data set, consisting of about one million observations, on credit history obtained from two major Swedish banks. The principal research interest involved with the data analysis is to model the probability of credit defaults by incorporating the systematic dependencies among the default events. In order to model the dependent credit defaults we adopt the framework of GLMM which is apopular approach to model correlated binary data. However, existing computational procedures for GLMM did not offer us the flexibility to incorporate the desired correlation structure of defaults events.For the feasible estimation of the GLMM we propose two estimation techniques being the fixed effects (FE) approach and the two-step pseudolikelihood approach (2PL). The preciseness of the estimation techniques and their computational advantages are studied by Monte-Carlo simulations and by applying them to the credit risk modelling. Regarding the prediction issue, we show how to apply the likelihood principle to carryout prediction with GLMM. We also provide an R add-in package to facilitate the predictive inference for GLMM.

    List of papers
    1. Computationally feasible estimation of the covariance structure in generalized linear mixed models 
    Open this publication in new window or tab >>Computationally feasible estimation of the covariance structure in generalized linear mixed models 
    2008 (English)In: Journal of Statistical Computation and Simulation, ISSN 0094-9655, E-ISSN 1563-5163, Vol. 78, no 12, p. 1229-1239Article in journal (Refereed) Published
    Abstract [en]

    In this paper, we discuss how a regression model, with a non-continuous response variable, which allows for dependency between observations, should be estimated when observations are clustered and measurements on the subjects are repeated. The cluster sizes are assumed to be large.We find that the conventional estimation technique suggested by the literature on generalized linear mixed models(GLMM) is slow and sometimes fails due to non-convergence and lack of memory on standard PCs.We suggest to estimate the random effects as fixed effects by generalized linear model and to derive the covariance matrix from these estimates.A simulation study shows that our proposal is feasible in terms of mean-square error and computation time.We recommend that our proposal be implemented in the software of GLMM techniques so that the estimation procedure can switch between the conventional technique and our proposal, depending on the size of the clusters.

    Place, publisher, year, edition, pages
    London: Taylor & Francis, 2008
    Keywords
    Monte Carlo simulations, Large sample, Interdependence, Cluster errors
    National Category
    Probability Theory and Statistics Social Sciences
    Research subject
    Statistics
    Identifiers
    urn:nbn:se:oru:diva-14060 (URN)10.1080/00949650701688547 (DOI)
    Note
    Mr Alam is also affiliated to Dalarna University, SE 781 88 Borlange, SwedenAvailable from: 2011-01-19 Created: 2011-01-19 Last updated: 2017-12-11Bibliographically approved
    2. Feasible estimation of generalized linear mixed models (GLMM) with weak dependency between groups
    Open this publication in new window or tab >>Feasible estimation of generalized linear mixed models (GLMM) with weak dependency between groups
    2010 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    This paper presents a two-step pseudo likelihood estimation for generalized linear mixed models with the random effects being correlated between groups. The core idea is to deal with the random intractable integrals in  the likelihood function by multivariate Taylor's approximation. The accuracy of the estimation technique is assessed in a Monte-Carlo study: An application of it with binary response variable is presented using a real dara set on credit defaults from two Swedish banks. Thanks to   the use of two-step estimation technique, the proposed algorithm outperforms conventional likelihood algoritms in terms of computational time.

    Keywords
    PQL, Laplace approximation, interdependence, cluster errrors, credit risk model
    National Category
    Social Sciences Probability Theory and Statistics
    Research subject
    Statistics
    Identifiers
    urn:nbn:se:oru:diva-14061 (URN)
    Note

    Mr Alam is also affiliated to Dalarna University, SE 781 88 Borlange, Sweden

    Available from: 2011-01-19 Created: 2011-01-19 Last updated: 2017-10-17Bibliographically approved
    3. Industry shocks and empirical evidences on defaults comovements
    Open this publication in new window or tab >>Industry shocks and empirical evidences on defaults comovements
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    It is commonly agreed that the credit defaults are correlated. However, the structure and magnitude of such dependence is not yet fully understood. This paper contributes to the current understanding about the defaults comovement in the following way. Assuming that the industries provides the basis of defaults comovement it provides empirical evidence as to how such comovements can be modeled using correlated industry shocks. Generalized linear mixed model (GLMM) with correlated random effects is used to model the defaults comovement. It is also demonstrated as to how a GLMM with complex correlation structure can be estimated through a very simple way. Empirical evidences are drawn through analyzing quarterly individual borrower level credit history data obtained from two major Swedish banks between the period 1994 and 2000. The results show that, conditional on the borrower level accounting data and macro business cycle variables, the defaults are correlated both within and between industries but not over time (quarters). A discussion has also been presented as to how a GLMM for defaults correlation can be explained.

    Keywords
    Credit risk, defaults contagion, GLMM, cluster correlation
    National Category
    Social Sciences Probability Theory and Statistics
    Research subject
    Statistics
    Identifiers
    urn:nbn:se:oru:diva-14072 (URN)
    Note

    Mr Alam is also affiliated to Dalarna University, SE 781 88 Borlange, Sweden

    Available from: 2011-01-19 Created: 2011-01-19 Last updated: 2017-10-17Bibliographically approved
    4. Likelihood prediction for generalized linear mixed models under covariate uncertainty
    Open this publication in new window or tab >>Likelihood prediction for generalized linear mixed models under covariate uncertainty
    2010 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    This paper presents the techniques of likelihood prediction for the generalized linear mixed models. Methods of likelihood prediction is explained through a series of examples; from a classical one to more complicated ones. The examples show, in simple cases, that the likelihood prediction (LP) coincides with already known best frequentist practice such as the best linear unbiased predictor. The paper outlines a way to deal with the covariate uncertainty while producing predictive inference. Using a Poisson error-in-variable general-ized linear model, it has been shown that in complicated cases LP produces better results than already know methods.

    Keywords
    Predictive likelihood, Pro…le predictive likelihood, Stochastic covariate, Coverage interval, Future value prediction, Credit risk prediction
    National Category
    Social Sciences Probability Theory and Statistics
    Research subject
    Statistics
    Identifiers
    urn:nbn:se:oru:diva-14079 (URN)
    Note

    Mr Alam is also affiliated to Dalarna University, SE 781 88 Borlange, Sweden

    Available from: 2011-01-19 Created: 2011-01-19 Last updated: 2017-10-17Bibliographically approved
    5. Computation and application of likelihood prediction with generalized linear and mixed models
    Open this publication in new window or tab >>Computation and application of likelihood prediction with generalized linear and mixed models
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    This paper presents the computation of likelihood prediction with the generalized linear and mixed models. The method of likelihood prediction is briefy discussed and approximate formulae are provided to make easy computation of the likelihoodprediction with generalized linear models. For complicated prediction problems, simulation methods are suggested. An R add-in package is accompanied to carryout the computation of the predictive inference with the generalized linear and mixed models. The likelihood prediction is applied to the prediction of the credit defaults using a real data set. Results show that the predictive likelihood can be a useful tool to predict portfolio credit risk.

    Keywords
    Predictive likelihood, Pro…le predictive likelihood, Coverage inter- val, Future value prediction, Credit risk prediction, R-package.
    National Category
    Social Sciences Probability Theory and Statistics
    Research subject
    Statistics
    Identifiers
    urn:nbn:se:oru:diva-14081 (URN)
    Note

    Mr Alam is also affiliated to Dalarna University, SE 781 88 Borlange, Sweden

    Available from: 2011-01-19 Created: 2011-01-19 Last updated: 2017-10-17Bibliographically approved
  • 6.
    Alam, Md. Moudud
    Örebro University, Swedish Business School at Örebro University.
    Feasible estimation of generalized linear mixed models (GLMM) with weak dependency between groups2010Manuscript (preprint) (Other academic)
    Abstract [en]

    This paper presents a two-step pseudo likelihood estimation for generalized linear mixed models with the random effects being correlated between groups. The core idea is to deal with the random intractable integrals in  the likelihood function by multivariate Taylor's approximation. The accuracy of the estimation technique is assessed in a Monte-Carlo study: An application of it with binary response variable is presented using a real dara set on credit defaults from two Swedish banks. Thanks to   the use of two-step estimation technique, the proposed algorithm outperforms conventional likelihood algoritms in terms of computational time.

  • 7.
    Alam, Md. Moudud
    Örebro University, Swedish Business School at Örebro University.
    Industry shocks and empirical evidences on defaults comovementsManuscript (preprint) (Other academic)
    Abstract [en]

    It is commonly agreed that the credit defaults are correlated. However, the structure and magnitude of such dependence is not yet fully understood. This paper contributes to the current understanding about the defaults comovement in the following way. Assuming that the industries provides the basis of defaults comovement it provides empirical evidence as to how such comovements can be modeled using correlated industry shocks. Generalized linear mixed model (GLMM) with correlated random effects is used to model the defaults comovement. It is also demonstrated as to how a GLMM with complex correlation structure can be estimated through a very simple way. Empirical evidences are drawn through analyzing quarterly individual borrower level credit history data obtained from two major Swedish banks between the period 1994 and 2000. The results show that, conditional on the borrower level accounting data and macro business cycle variables, the defaults are correlated both within and between industries but not over time (quarters). A discussion has also been presented as to how a GLMM for defaults correlation can be explained.

  • 8.
    Alam, Md. Moudud
    Örebro University, Swedish Business School at Örebro University.
    Likelihood prediction for generalized linear mixed models under covariate uncertainty2010Manuscript (preprint) (Other academic)
    Abstract [en]

    This paper presents the techniques of likelihood prediction for the generalized linear mixed models. Methods of likelihood prediction is explained through a series of examples; from a classical one to more complicated ones. The examples show, in simple cases, that the likelihood prediction (LP) coincides with already known best frequentist practice such as the best linear unbiased predictor. The paper outlines a way to deal with the covariate uncertainty while producing predictive inference. Using a Poisson error-in-variable general-ized linear model, it has been shown that in complicated cases LP produces better results than already know methods.

  • 9.
    Alam, Md Moudud
    Sch Technol & Business Studies, Dalarna Univ, Falun, Sweden; Swedish Business Sch, Univ Örebro, Örebro, Sweden.
    Likelihood Prediction for Generalized Linear Mixed Models under Covariate Uncertainty2014In: Communications in Statistics - Theory and Methods, ISSN 0361-0926, E-ISSN 1532-415X, Vol. 43, no 2, p. 219-234Article in journal (Refereed)
    Abstract [en]

    This article presents the techniques of likelihood prediction for the generalized linear mixed models. Methods of likelihood prediction are explained through a series of examples; from a classical one to more complicated ones. The examples show, in simple cases, that the likelihood prediction (LP) coincides with already known best frequentist practice such as the best linear unbiased predictor. This article outlines a way to deal with the covariate uncertainty while producing predictive inference. Using a Poisson errors-in-variable generalized linear model, it has been shown in certain cases that LP produces better results than already known methods.

  • 10.
    Alam, Md. Moudud
    et al.
    Örebro University, Swedish Business School at Örebro University.
    Carling, Kenneth
    Dalarna University, SE 781 88 Borlange, Sweden.
    Computationally feasible estimation of the covariance structure in generalized linear mixed models 2008In: Journal of Statistical Computation and Simulation, ISSN 0094-9655, E-ISSN 1563-5163, Vol. 78, no 12, p. 1229-1239Article in journal (Refereed)
    Abstract [en]

    In this paper, we discuss how a regression model, with a non-continuous response variable, which allows for dependency between observations, should be estimated when observations are clustered and measurements on the subjects are repeated. The cluster sizes are assumed to be large.We find that the conventional estimation technique suggested by the literature on generalized linear mixed models(GLMM) is slow and sometimes fails due to non-convergence and lack of memory on standard PCs.We suggest to estimate the random effects as fixed effects by generalized linear model and to derive the covariance matrix from these estimates.A simulation study shows that our proposal is feasible in terms of mean-square error and computation time.We recommend that our proposal be implemented in the software of GLMM techniques so that the estimation procedure can switch between the conventional technique and our proposal, depending on the size of the clusters.

  • 11. Alam, Moudud
    et al.
    Carling, Kenneth
    Dalarna University, Borlänge, Sweden.
    Chen, Rui
    Liang, Yuli
    Department of Statistics, Stockholm University, Stockholm, Sweden.
    How to determine the progression of young skiers?2008In: CHANCE: New Directions for Statistics and Computing, ISSN 0933-2480, Vol. 21, no 4, p. 13-19Article in journal (Refereed)
  • 12.
    Aldén, Michelle
    et al.
    Örebro University, School of Science and Technology.
    Wengelin, Nathalie
    Örebro University, School of Science and Technology.
    En systematisk litteraturstudie om olika undervisningsmetoders påverkan på elevers motivation i matematik.2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Pupils' achievement and knowledge in mathematics is a highly current issue that is discussed and compared both in Sweden and internationally. International measurements have for a long time pointed to a lower level of knowledge and in Sweden they discuss the reasons for these downward results. Researchers believe that pupils' attitude, adjustment and motivation to the subject of mathematics are one of the reasons when they are considered crucial to address the subject of mathematics. It also strives to answer the teaching methods that influence students' motivation. The Swedish curriculum for elementary school states that teaching should promote students' interest and the desire to learn, which represents a large part of the motivation of students. The choice of teaching method can thus influence students' motivation. In this systematic literature study, three different main categories of teaching methods appear in the results; Methods where the teacher is at the center, methods where technical aids are at the center and methods in which the student is at the center. The categories consist of articles that deal with different types of teaching methods, which in the result had an influence on student motivation.

  • 13.
    Allansson, Claes
    et al.
    Örebro University, Örebro University School of Business.
    Kumlin, Marina
    Örebro University, Örebro University School of Business.
    En studie av svensk ishockey: Olika faktorers påverkan på utgången av en förlängning2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 14.
    Almquist, Linnea
    Örebro University, School of Science and Technology.
    Aktiviteter i matematikundervisning: En studie om aktiviteter som erbjuds i lärarhandledningar för matematikundervisningi årskurs 1–32017Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Att använda lärarhandledningar som stöd har länge haft en betydande roll i finsk matematikundervisning, och på senare år har flera finska läromedel översatts till svenska (Hoelgaard, 2015). Syftet med den här studien var att bidra med ökad förståelse för vilken typ av stöd, i form av aktiviteter, en lärarhandledning som översatts från finska till svenska ger. Aktiviteter för nio lektioner ur tre lärarhandledningar för årskurs 1–3 från läromedlet ’Favorit matematik’ har studerats utifrån en kvalitativ textanalys, med kvantitativa inslag. Genom en kvalitativ intervju med två matematiklärare i årskurs 1–3 som använder de aktuella lärarhandledningarna har aktiviteterna studerats utifrån vilka aktiviteter lärarna använder, inte använder samt vilka aktiviteter de önskar fanns i lärarhandledningarna. Resultatet av textanalysen visar att det i det analyserade materialet erbjuds 102 aktiviteter. Elever arbetar enskilt och förvärvar kunskap i nästan en tredjedel av dem, men ett brett urval av aktiviteter där elever arbetar tillsammans och lär sig genom deltagande erbjuds också. Lärarna upplever dock att det finns ett riktat fokus mot enskilt arbete i elevboken, vilket också blir synligt genom textanalysen.

  • 15.
    Almqvist, Linnea
    Örebro University, School of Science and Technology.
    Aktiviteter i matematikundervisning: En studie om aktiviteter som erbjuds i lärarhandledningar för matematikundervisning i årskurs 1–32017Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Using teacher guides as support for education is common and has been common in Finnish mathematics education for a long time. During the last few years Finnish curriculum materials have been translated into Swedish (Hoelgaard, 2015). The aim of this study was to contribute with knowledge about what kind of support, in form of activities, teacher guides provide. Activities for nine lessons in three teacher guides, for education in year 1-3 in Swedish compulsory school, from the curriculum material ‘Favorit matematik’ have been analysed with a qualitative text analysis with quantitative elements. Which activities teachers choose to use, not to use and what activities they wish were offered have been studied by interviewing two teachers in year 1-3, whom uses these teacher guides. The result from the text analysis show that 102 activities are offered in the analysed material. Almost one third of them are activities where students work on their own acquiring knowledge, but a wide selection of activities where student work together and knowledge comes from participating, are also offered in the teacher guides. Though, the teachers experience that there is a focus on activities where student work on their own with the textbook, which is confirmed by the text analysis.

  • 16.
    Alsammarraie, Zeinab
    et al.
    Örebro University, Örebro University School of Business.
    Rådelid, Daniel
    Örebro University, Örebro University School of Business.
    Födelsemånandens betydelse för elitutövande individer: En studie som undersöker sporterna fotboll och friidrott2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 17.
    Alves, Maria
    Örebro University, School of Science and Technology.
    Stabilization of DierentialSystems with HybridFeedback Control2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this paper two-dimensional systems of dierential equations are consideredtogether with their stabilization by a hybrid feedback control. A stabilizinghybrid control for an arbitrary controlled system that belongs to acertain category within two-dimensional systems is constructed as a result ofthis study and some stabilization proprieties of the system with the obtainedhybrid control are presented.

  • 18.
    Amnå, Erik
    et al.
    Örebro University, Department of Social and Political Sciences.
    Halleröd, Björn
    Umeå universitet.
    Hallqvist, Johan
    Karolinska Institutet.
    Lundberg, Ingvar
    Uppsala universitet.
    Sundqvist, Jan
    Karolinska Institutet.
    Theorell, Töres
    Karolinska Institutet.
    Thorslund, Mats
    Karolinska Institutet.
    Vingård, Eva
    Uppsala universitet.
    Wall, Stig
    Umeå universitet.
    Åkerstedt, Torbjörn
    Karolinska Institutet.
    Östergren, Per Olof
    Lunds universitet.
    En halv miljard av statens pengar riskerar att slösas bort2007In: Göteborgs-Posten, Vol. 2007-09-13, p. 47-47Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Minskade anslag gör att den årliga undersökningen om våra levnadsförhållanden hotas att halveras. Det kan drabba redan svaga grupper som äldre, invandrare och ensamstående föräldrar.

  • 19.
    Andersen, Jørgen Ellegaard
    et al.
    CTQM, Department of Mathematical Sciences, Aarhus University, Aarhus, Denmark.
    Fjelstad, Jens
    Department of Physics, Karlstad University, Karlstad, Sweden.
    On Reducibility of Mapping Class Group Representations: The SU(N) case2010In: Noncommutative structures in mathematics and physics / [ed] Stefaan Caenepeel, Jürgen Fuchs, Simone Gutt, Christophe Schweigert, Alexander Stolin, Freddy Van Oystaeyen, Brussels: Koninklijke vlaamse academie van Belgie voor Wetenschappen en kunsten, 2010, p. 27-45Conference paper (Refereed)
    Abstract [en]

    We review and extend the results of [1] that gives a condition for reducibility of quantum representations of mapping class groups constructed from Reshetikhin-Turaev type topological quantum field theories based on modular categories. This criterion is derived using methods developed to describe rational conformal field theories, making use of Frobenius algebras and their representations in modular categories. Given a modular category C, a rational conformal field theory can be constructed from a Frobenius algebra A in C. We show that if C contains a symmetric special Frobenius algebra A such that the torus partition function Z(A) of the corresponding conformal field theory is non-trivial, implying reducibility of the genus 1 representation of the modular group, then the representation of the genus g mapping class group constructed from C is reducible for every g\geq 1. We also extend the number of examples where we can show reducibility significantly by establishing the existence of algebras with the required properties using methods developed by Fuchs, Runkel and Schweigert. As a result we show that the quantum representations are reducible in the SU(N) case, N>2, for all levels k\in \mathbb{N}. The SU(2) case was treated explicitly in [1], showing reducibility for even levels k\geq 4.

  • 20.
    Andersen, Jørgen Ellegaard
    et al.
    Center for Quantum Geometry of Moduli Spaces, University of Aarhus, Århus, Denmark.
    Fjelstad, Jens
    Department of Physics, Karlstad University, Karlstad, Sweden.
    Reducibility of quantum representations of mapping class groups2010In: Letters in Mathematical Physics, ISSN 0377-9017, E-ISSN 1573-0530, Vol. 91, no 3, p. 215-239Article in journal (Refereed)
    Abstract [en]

    In this paper we provide a general condition for the reducibility of the Reshetikhin–Turaev quantum representations of the mapping class groups. Namely, for any modular tensor category with a special symmetric Frobenius algebra with a non-trivial genus one partition function, we prove that the quantum representations of all the mapping class groups built from the modular tensor category are reducible. In particular, for SU(N) we get reducibility for certain levels and ranks. For the quantum SU(2) Reshetikhin–Turaev theory we construct a decomposition for all even levels. We conjecture this decomposition is a complete decomposition into irreducible representations for high enough levels.

  • 21.
    Andersson, Gustaf
    Örebro University, School of Science and Technology.
    Intuitionen bakom analytisk fortsättning2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I denna uppsats om analytisk fortsättning så ges en intuitiv inblick hur denna process går till. Av analytisk fortsättning får vi ett sätt att utöka bortom den domän där funktionen från början är definierad. En fortsättning kan fås på flera sätt. Det är framförallt en metod som presenteras i uppsatsen, nämligen analytisk fortsättning längs kurvor. Genom att studera homotopier så får vi ett sätt att se på hur dessa kurvor förhåller sig till varandra. Homotopier ger oss också viktiga definitioner som enkelt sammanhängande område, vilket kommer ha stor betydelse när vi ser på en analytisk fortsättning. När vi studerar hur en analytisk fortsättning påverkas av olika områden så fås en viktig sats, nämligen Monodromisatsen som ger oss ett sätt att bygga analytiska funktioner.

  • 22.
    Andersson, Jens
    et al.
    Örebro University, Örebro University School of Business.
    Munter, Petrus
    Örebro University, Örebro University School of Business.
    Fotbollshörnor - En statistisk oddsmodell2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 23.
    Andersson, Johan
    et al.
    Örebro University, Örebro University School of Business.
    Törnqvist, Viktor
    Örebro University, Örebro University School of Business.
    Valet efter kvalet: En statistisk utvärdering av längdskidåkningenssprinttävlingar2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 24.
    Andersson, Michael K.
    et al.
    Sveriges Riksbank.
    Karlsson, Sune
    Örebro University, Swedish Business School at Örebro University.
    Bayesian forecast combination for VAR models2008In: Bayesian Econometrics / [ed] Siddhartha Chib, William Griffiths, Gary Koop, Dek Terrell, Bingley: Emerald , 2008, p. 501-524Chapter in book (Other academic)
  • 25.
    Andersson, Michael K.
    et al.
    National Institute of Economic Research, Stockholm, Sweden.
    Karlsson, Sune
    Department of Economic Statistics, Stockholm School of Economics, Stockholm, Sweden.
    Bootstrapping Error Component Models2001In: Computational statistics (Zeitschrift), ISSN 0943-4062, E-ISSN 1613-9658, Vol. 16, no 2, p. 221-231Article in journal (Refereed)
    Abstract [en]

    This paper proposes several resampling algorithms suitable for error component models and evaluates them in the context of bootstrap testing. In short, all the algorithms work well and lead to tests with correct or close to correct size. There is thus little or no reason not to use the bootstrap with error component models.

  • 26.
    Andersson, Oskar
    Örebro University, School of Science and Technology.
    Framgångsrika åtgärdsprogram: En systematisk litteraturstudie som kartlägger faktorer som kan öka måluppfyllelsen i åtgärdsprogramsprocessen i matematik.2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Both from previous research and from the media the documentation form of education plan receives a lot of criticism in terms of both content and design. An education plan must be written if a student is suspected not to achieve current knowledge requirements. It will therefore be important in a subject like mathematics which has a relatively high percentage of students who fails to achieve the knowledge requirements. Therefore it is important that the process with the education plan fulfils its purpose. This systematic literature study aims to identify factors that may increase the effectiveness of education plan process in mathematics. The results and conclusions of this study put forward several different factors that must interact in order to make the educational plan process in mathematics successful. Factors that this study concludes that might have an affect are for example, pupils' and parents' participation and the headmasters’ commitment and volition to participate.

  • 27.
    Andersson, Oskar
    Örebro University, School of Science and Technology.
    Åtgärdsprogram i matematik: Vägen mot kunskapskraven?2015Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Academic year 2013/2014 almost every tenth student in grades 6 lacks passing grade in mathematics. Mathematics is one of the three subjects that a student needs to pass in order to later in their schooling get high school eligibility. The school has a statutory mandate to provide all students with opportunities to achieve acceptable knowledge requirements and if this is not done, a special support should be deployed and documented in an education plan. Education plans must constantly endure a lot of criticism because they do often lack in quality.

    Through a qualitative text analysis 15 education plans will be reviewed for the purpose of developing knowledge about how the work with special support in math are projected and processed. The study shows that there is a link between education plan and knowledge requirement in 22 of the 29 necessary descriptions in 11 of the 15 education plans. In four of the 15 education plans a description of the student's special needs based on the Mathematical Syllabuses core content and given abilities is missing entirely. Of the 38 measures in the education plans there are six with distinct character and the remaining 32 are of a diffuse character. A clear majority of the measures do not fulfill the criteria of evaluability and concreteness specified in Skolverkets general advice. The study shows that 26 of the 38 measures are related to current research on what is considered to be favorable measures for students in mathematics difficulties. Only two of the 15 education plans shows a clear connection between the students written needs and measures.

  • 28.
    Andersson, Per Gösta
    Örebro University, Swedish Business School at Örebro University.
    A Simple Correlation Adjustment Procedure Applied to Confidence Interval Construction2009In: American Statistician, ISSN 0003-1305, E-ISSN 1537-2731, Vol. 63, no 3, p. 258-262Article in journal (Refereed)
    Abstract [en]

    The assumption of approximate normality of a pivotal used for constructing confidence intervals or tests often is violated by a substantial correlation between the point estimator at hand and the estimator of its variance. This can be caused by underlying skewness of data, generating both bias and skewness of the pivotal and leading to, for example, confidence intervals with poorer coverage properties, especially for one-sided intervals. We present in a general setting a simple, yet effective procedure that takes into account this correlation and leads to alternative adjusted intervals with more appealing coverage properties. We provide examples, including a simulation study.

  • 29.
    Andersson, Stefan
    Örebro University, Swedish Business School at Örebro University.
    Estimering av den årliga rundgången i de svenska skatte- och transfereringssystemen2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 30.
    Andrén, Daniela
    et al.
    Örebro University, Örebro University School of Business.
    Clark, Andrew
    Paris School of Economics, Paris, France.
    D'Ambrosio, Conchita
    Université du Luxembourg, Esch-sur-Alzette, Luxembourg.
    Karlsson, Sune
    Örebro University, Örebro University School of Business.
    Pettersson, Nicklas
    Örebro University, Örebro University School of Business.
    Subjective and physiological measures of well-being: an exploratory analysis using birth-cohort data2017Report (Other academic)
    Abstract [en]

    We use a rich longitudinal data set following a cohort of Swedish women from age 10 to 49 to analyse the effects of birth and early-life conditions on adulthood outcomes. These latter include both well-being and the stress hormone cortisol. Employment and marital status are important adult determinants of well-being. Log family income and absence from school also predict adult well-being, although their importance falls when controlling for adult and birth characteristics. Among the birth characteristics, we find that high birth weight (>4.3kg) affects adult well-being. We predict the level of adult cortisol only poorly, and suggest that the relationship between life satisfaction and cortisol is non-monotonic: both high and low cortisol are negatively correlated with life satisfaction. The results from an OLS life satisfaction regression and a multinomial logit of high or low cortisol (as compared to medium) are more similar to each other.

  • 31.
    Andrén, Daniela
    et al.
    Örebro University, Örebro University School of Business.
    Clark, Andrew E.
    Paris School of Economics - CNRS, Paris, France.
    D’Ambrosio, Conchita
    Université du Luxembourg, Esch-sur-Alzette, Luxembourg.
    Karlsson, Sune
    Örebro University, Örebro University School of Business.
    Pettersson, Nicklas
    Örebro University, Örebro University School of Business.
    New ways to measure well-being?: A first joint analysis of subjective and objective measures2018Report (Other academic)
    Abstract [en]

    Our study is, to our knowledge, the first joint analysis of subjective and objective measures of well-being. Using a rich longitudinal data from the mothers pregnancy until adulthood for a birth cohort of children who attended school in Örebro during the 1960s, we analyse in a first step how subjective (self-assessed) and objective (cortisol-based) measures of well-being are related to each other. In a second step, life-course models for these two measures are estimated and compared with each other. Despite the fact that our analysis is largely exploratory, our results suggest interesting possibilities to use objective measures to measure well-being, even though this may imply a greater degree of complexity.

  • 32. Arnrup, Kristina
    et al.
    Broberg, Anders G.
    Berggren, Ulf
    Bodin, Lennart
    Örebro University, Department of Business, Economics, Statistics and Informatics.
    Temperamental reactivity and negative emotionality in uncooperative children referred to specialized paediatric dentistry compared to children in ordinary dental care2007In: International Journal of Paediatric Dentistry, ISSN 0960-7439, E-ISSN 1365-263X, Vol. 17, no 6, p. 419-429Article in journal (Refereed)
    Abstract [en]

    Background: Current treatment of children with dental behaviour management problems (DBMP) is based on the presupposition that their difficulties are caused by dental fear, but is this always the case? Objectives: The aim of this study was to study temperamental reactivity, negative emotionality, and other personal characteristics in relation to DBMP in 8- to 12-year-old children. Methods: Forty-six children referred because of DBMP (study group) and 110 children in ordinary dental care (reference group) participated. The EASI tempramental survey assessed temperamental reactivity and negative emotionality, the Child Behaviour Questionnaire internalizing and externalizing behaviour problems, and the Children's Fear Survey Schedule general and dental fears. Cluster analyses and tree-based modelling were used for data analysis. Results: Among the five clusters identified, one could be characterized as 'balanced temperament'. Thirty-five per cent of the reference group compared to only 7% of the study group belonged to this cluster. Negative emotionality was the most important sorting variable. Conclusions: Children referred because of DBMP differed from children in ordinary dental care, not only in dental fear level, but also in personal characteristics. Few of the referred children were characterized by a balanced temperament profile. It is important to consider the dual impact of emotion dysregulation and emotional reactivity in the development of DBMP.

  • 33.
    Arvidsson, Mattias
    Örebro University, Örebro University School of Business.
    An empirical examination of the Fisher hypothesis in Sweden2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 34.
    Arvidsson, Mattias
    Örebro University, School of Science and Technology.
    Introduktion till Markovkedjor2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 35.
    Arvidsson, Mattias
    et al.
    Örebro University, Swedish Business School at Örebro University.
    Enmalm, Susanne
    Örebro University, Swedish Business School at Örebro University.
    Vilken är den optimala parkeringsplatsen?: - En undersökande artikel för att statistiskt finna den optimala parkeringsplatsen.2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 36.
    Asgharian, Hossein
    et al.
    Department of Economics, Knut Wicksell Center for Financial Studies, Lund University, Sweden.
    Hou, Ai Jun
    Department of Business and Economics, Southern Denmark University, Odense, Denmark.
    Javed, Farrukh
    Department of Statistics, Lund University, Sweden.
    The Importance of the Macroeconomic Variables in Forecasting Stock Return Variance: A GARCH-MIDAS Approach2013In: Journal of Forecasting, ISSN 0277-6693, E-ISSN 1099-131X, Vol. 32, no 7, p. 600-612Article in journal (Refereed)
    Abstract [en]

    This paper applies the GARCH-MIDAS (mixed data sampling) model to examine whether information contained in macroeconomic variables can help to predict short-term and long-term components of the return variance. A principal component analysis is used to incorporate the information contained in different variables. Our results show that including low-frequency macroeconomic information in the GARCH-MIDAS model improves the prediction ability of the model, particularly for the long-term variance component. Moreover, the GARCH-MIDAS model augmented with the first principal component outperforms all other specifications, indicating that the constructed principal component can be considered as a good proxy of the business cycle.

  • 37.
    Ashraf, Jawad Hussain
    Örebro University, Swedish Business School at Örebro University.
    Nonparametric Estimation of Stochastic Volatility2009Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 38.
    Asif, Muneeb
    Örebro University, Örebro University School of Business.
    Bayesian Inference for the Global Minimum Variance Portfolio2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
  • 39.
    Asif, Muneeb
    Örebro University, Örebro University School of Business.
    Predicting the Success of Bank Telemarketing using various Classification Algorithms2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
  • 40.
    Askeblad, Lina
    Örebro University, School of Science and Technology.
    Särskilt begåvade elever i matematik: Pedagogers synsätt och uppfattningar2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Målet med den här studien har varit att genom en enkät och intervjuer undersöka verksamma lärares och en skolledares synsätt och uppfattningar kring arbetet med särskilt begåvade elever inom matematiken. Det skulle besvaras med hjälp av tre frågeställningar: Vilka sätt eleverna identifieras; Hur stöd och stimulering ges; Vilket organisatoriskt stöd lärarna får eller saknar.

    Resultatet har visat att informanterna arbetar relativt lika i arbetet med att identifiera och stimulera eleverna som är särskilt begåvade. En varierad undervisning är viktig för att identifiera eleverna, men även för att ge stöd och stimulera eleverna i deras utveckling. Med en varierad undervisning finns det fler möjligheter för eleverna att identifieras då de elever som upplever uppgifter med standardlösningar tråkiga får andra sätt att delta. Problemlösning är ett sätt att variera undervisningen, de uppgifterna går ofta att förändra efter elevernas nivå.

    Samarbete är en framgångsfaktor för att identifiera, ge stöd och stimulera eleverna. Att identifiera eleverna med hjälp av hemmet är positivt och ett samarbete med hemmen är viktiga i skolan. Om en lärare får information överlämnad från en annan lärare är det viktigt att hen inte endast tittar på den informationen utan även gör en egen bedömning av elevernas förmåga. Nivågruppering är positivt, eleverna i denna studie har även möjlighet att gå till en annan klass och några informanter använder sig av flexibel skola.

    Mycket av det stöd som informanterna beskriver är organisatoriskt stöd, t.ex. att schemalägga lektioner samtidigt. Informanterna upplever att de får bra stöd från kollegor och ledning medan stöd från kommunen inte är lika bra. Det stöd som efterfrågas är stöd som kräver en större budget, något som den enskilda skolan inte kan påverka speciellt mycket.

  • 41.
    Ayres, Gabriela
    et al.
    Örebro University, Örebro University School of Business.
    Wei, Wei
    Örebro University, Örebro University School of Business.
    Credit Scoring Model Applications: Testing Multinomial Targets2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 42.
    Banaem, Hossein Yousefi
    et al.
    Tehran University of Medical Science, Tehran, Iran.
    Ahmadian, Alireza
    Tehran University of Medical Science, Tehran, Iran.
    Saberi, Hooshangh
    Tehran University of Medical Science, Tehran, Iran.
    Daneshmehr, Alireza
    University of Tehran, Tehran, Iran.
    Khodadad, Davood
    Tehran University of Medical Science, Tehran, Iran.
    Brain tumor modeling: glioma growth and interaction with chemotherapy2011In: International Conference on Graphic and Image Processing (ICGIP) / [ed] Yi Xie & Yanjun Zheng, SPIE - International Society for Optical Engineering, 2011, Vol. 8285, article id 82851MConference paper (Refereed)
    Abstract [en]

    In last decade increasingly mathematical models of tumor growths have been studied, particularly on solid tumors which growth mainly caused by cellular proliferation. In this paper we propose a modified model to simulate the growth of gliomas in different stages. Glioma growth is modeled by a reaction-advection-diffusion. We begin with a model of untreated gliomas and continue with models of polyclonal glioma following chemotherapy. From relatively simple assumptions involving homogeneous brain tissue bounded by a few gross anatomical landmarks (ventricles and skull) the models have been expanded to include heterogeneous brain tissue with different motilities of glioma cells in grey and white matter. Tumor growth is characterized by a dangerous change in the control mechanisms, which normally maintain a balance between the rate of proliferation and the rate of apoptosis (controlled cell death). Result shows that this model closes to clinical finding and can simulate brain tumor behavior properly.

  • 43.
    Bannocks, Robert
    Örebro University, Örebro University School of Business.
    Investigating clustering within the relationship between rateable values and selling price of property in Sweden2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Several studies have found segmentation within Real Estate markets. Real Estate markets are often modelled by hedonic models and these often rely on proxy variables to represent a number of hedonic characteristics. The rateable value of a property is designed to be a measure of its market value and is often used as a proxy for difficult to observe or unobservable characteristics in such studies. Such studies often assume that the rateable value is simply proportional to the market value of a property. The presence of segmentation may invalidate this assumption. A sample of data from the Real Property Register maintained by Lantmäteriet, the Swedish land registry, were investigated to explore the relationship between land values and rateable values. The sample studied contains the selling price of properties sold across a range of years, the year of sale and a limited number of other characteristics. However, the rateable values for these properties are only available for a given year, the calendar year 2009. Accounting for inflationary effects is therefore necessary and was attempted in the model with indicator variables and then a quadratic expression. An inconsistent relationship between the selling price and the rateable value was found when a simple non-segmented model was used. With the absence of other likely explanatory variables in the data clustering techniques were considered to anatomise the data. Finite Mixture Modelling is the most appropriate method of classifying this data into clusters which are modelled as a finite mixture of regression models. The investigation found the presence of 3 distinct clusters. None of the variables in the data set appear to cause cluster affiliation.

  • 44.
    Baquedano, Jonathan
    Örebro University, Swedish Business School at Örebro University.
    Jämförelse av svarskvalitet i Webbenkäter kontra Pappersenkäter2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 45.
    Bauder, David
    et al.
    Department of Mathematics, Humboldt-University of Berlin, Berlin, Germany.
    Bodnar, Taras
    Department of Mathematics, Stockholm University, Stockholm, Sweden.
    Mazur, Stepan
    Örebro University, Örebro University School of Business. Department of Statistics.
    Okhrin, Yarema
    Department of Statistics, University of Augsburg, Augsburg, Germany.
    Bayesian inference for the tangent portfolio2018In: International Journal of Theoretical and Applied Finance, ISSN 0219-0249, Vol. 21, no 8, p. 25article id 1850054Article in journal (Other academic)
    Abstract [en]

    In this paper we consider the estimation of the weights of tangent portfolios from the Bayesian point of view assuming normal conditional distributions of the logarithmic returns. For diffuse and conjugate priors for the mean vector and the covariance matrix, we derive stochastic representations for the posterior distributions of the weights of tangent portfolio and their linear combinations. Separately we provide the mean and variance of the posterior distributions, which are of key importance for portfolio selection. The analytic results are evaluated within a simulation study, where the precision of coverage intervals is assessed. 

  • 46.
    Belitskii, Genrich
    et al.
    Department of Mathematics, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
    Dmytryshyn, Andrii
    Faculty of Mechanics and Mathematics, Kiev National Taras Shevchenko University, Kiev, Ukraine.
    Lipyanski, Ruvim
    Department of Mathematics, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
    Sergeichuk, Vladimir
    Institute of Mathematics, Kiev, Ukraine.
    Tsurkov, Arkady
    Department of Mathematics, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
    Problems of classifying associative or Lie algebras over a field of characteristic not 2 and finite metabelian groups are wild2009In: The Electronic Journal of Linear Algebra, ISSN 1537-9582, E-ISSN 1081-3810, Vol. 18, p. 516-529, article id 41Article in journal (Refereed)
    Abstract [en]

    Let F be a field of characteristic different from 2. It is shown that the problems of classifying

    (i) local commutative associative algebras over F with zero cube radical,

    (ii) Lie algebras over F with central commutator subalgebra of dimension 3, and

    (iii) finite p-groups of exponent p with central commutator subgroup of order  are hopeless since each of them contains

    • the problem of classifying symmetric bilinear mappings UxU → V , or

    • the problem of classifying skew-symmetric bilinear mappings UxU → V ,

    in which U and V are vector spaces over F (consisting of p elements for p-groups (iii)) and V is 3-dimensional. The latter two problems are hopeless since they are wild; i.e., each of them contains the problem of classifying pairs of matrices over F up to similarity.

  • 47.
    Bengtsson, Pernilla
    Örebro University, Department of Business, Economics, Statistics and Informatics.
    Framtagande av modell för skattning av antalet vakanser med poissonregression i konjunkturstatistiken över vakanser2007Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    SCB gör en vakansundersökning varje månad, granskningssystemet för undersökningen ska eventuellt ändras till en metod som kallas för significance editing. Med den granskningsmetoden behövs ett jämförelsevärde för att kunna avgöra om enkäten är korrekt besvarad eller om ett värde är misstänkt och behöver granskas ytterligare. Uppsatsens syfte är att genom poissonregression ta fram en bra modell som kan generera detta jämförelsevärde. Ett antal hjälpvariabler togs fram och testades för att se om de passade i poissonregressionen och om de kunde förklara antalet vakanser. De hjälpvariabler som har använts är antal vakanser föregående månad, antal anställda på arbetsstället, dummyvariabel för Sveriges län och månaderna. Metoden testades på två olika branscher, pappersmassaindustrin och metallindustrin. I de resultat som togs fram kan man se att variablerna antal anställda på arbetsstället och antalet vakanser föregående månad alltid blir signifikanta och tillför till att skatta antalet vakanser. Därför kan dessa användas för att skatta ett jämförelsevärde. Län och månader behövs i modellen men det är olika län och månader som blir signifikanta för de två olika branscherna. Generellt kan man dra slutsatsen att antalet vakanser ökar på våren och sommaren. Huruvida metoden går att tillämpa på det ogranskade datamaterialet får vidare undersökningar visa.

  • 48.
    Bergman, Lars
    et al.
    Stockholm University.
    Trost, Kari
    Örebro University, School of Law, Psychology and Social Work.
    The person-oriented vs.the variable-oriented approach: Complementary, antagonistic, or exploringdifferent worlds?2006In: Merrill-Palmer quarterly, ISSN 0272-930X, E-ISSN 1535-0266, Vol. 52, no 3, p. 601-632Article in journal (Refereed)
    Abstract [en]

    The present commentary gives a brief overview of the person-oriented and variable-oriented approaches, how they are commonly used in longitudinal research, and what one should take into consideration before using either approach. In addition to presenting an empirical example on girls’ adjustment problems using both approaches, this commentary uses the contributions in the present issue of Merrill Palmer Quarterly to illustrate some of the main issues surrounding these two perspectives. Special attention is also given to the contrast between the person-oriented and variable-oriented approaches in terms of aggregation and disaggregation, model appropriateness and usefulness, and prediction as a goal. Future directions with regard to implementing a personoriented approach are discussed, including the importance of conceptual clarity, practical and theoretical training, and method development.

  • 49.
    Bergman, Olivia
    Örebro University, School of Science and Technology.
    Konsten att bestämma π genom slumpen2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med detta arbete var att jämföra olika stokastiska processer som generar π, de olika modellerna som  studerades var modeller baserades på Buffons-, Buffon-Laplaces- och kasta pil-problem och förutom att lösa respektive problem så undersöktes bland annat om det gick att skatta π med motsvarande problem i högre dimensioner.

     

    Innan problemen undersöktes fick läsaren en bakgrund med nödvändiga definitioner och satser inom sannolikhetsteorin, där bland annat Kolmogorovs axiomsystem, fördelningars täthetsfunktion, väntevärde och varians presenterades, men också olika definitioner av konvergens som i sin tur ledde till en sats: Deltametoden, en generalisering av Centrala gränsvärdessatsen. Allt detta tillsammans gjorde det möjligt att lösa problemen och sedan kunna jämföra dem med hjälp av respektive skattnings varians.

     

    Innan problemen undersöktes fick läsaren en bakgrund med nödvändiga definitioner och satser inom sannolikhetsteorin, där bland annat Kolmogorovs axiomsystem, fördelningars täthetsfunktion, väntevärde och varians presenterades, men också olika definitioner av konvergens som i sin tur ledde till en sats: Deltametoden, en generalisering av Centrala gränsvärdessatsen. Allt detta tillsammans gjorde det möjligt att lösa problemen och sedan kunna jämföra dem med hjälp av respektive skattnings varians.

  • 50.
    Bergström, Sanna
    et al.
    Örebro University, Örebro University School of Business.
    Lönnquist, Anders
    Örebro University, Örebro University School of Business.
    Handedness & Stress resilience - A cross-sectional evaluation of possible relationship2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
1234567 1 - 50 of 682
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • 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