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  • 1.
    Abgaryan, Garnik V.
    et al.
    Department of Applied Mathematics and Artificial Intelligence, Institute of Computational Mathematics and Information Technology, Kazan Federal University, Kremlevskaya Street 35, Kazan 420008, Russia.
    Shestopalov, Yury
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics. Russian Technological University MIREA, Moscow 119454, Russia.
    TE-Polarized Electromagnetic Wave Diffraction by a Circular Slotted Cylinder2023In: Mathematics, E-ISSN 2227-7390, Vol. 11, no 9, article id 1991Article in journal (Refereed)
    Abstract [en]

    The problem of diffraction of a TE-polarized electromagnetic wave by a circular slotted cylinder is investigated. The boundary value problem in question for the Helmholtz equation is reduced to an infinite system of linear algebraic equations of the second kind (SLAE-II) using integral summation identities (ISI). A detailed study of the matrix operator of the problem is performed and its Fredholm property in the weighted Hilbert space of infinite sequences is proven. The convergence of the truncation method constructed in the paper for the numerical solution of SLAE-II is justified and the results of computations are presented and discussed, specifically considering the determination of resonance modes.

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  • 2.
    Alekseev, Gennady
    et al.
    Institute of Applied Mathematics FEB RAS, Vladivostok, Russia; School of Natural Sciences, Far Eastern Federal University, Vladivostok, Russia .
    Tereshko, Dmitri
    Institute of Applied Mathematics FEB RAS, Vladivostok, Russia.
    Shestopalov, Yury
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Optimization approach for axisymmetric electric field cloaking and shielding2021In: Inverse Problems in Science and Engineering, ISSN 1741-5977, E-ISSN 1741-5985, Vol. 29, no 1, p. 40-55Article in journal (Refereed)
    Abstract [en]

    In this paper we study inverse problems of electric conductivity that arise in the design of spherical shielding or cloaking shells and other functional devices used to control static electric fields. The shells are considered consisting of a finite number of layers filled with homogeneous isotropic or anisotropic medium. The inverse problems under study are reduced to control problems with the layers electric conductivities taken as controls. A different choice of minimized functionals allows us to solve a wide range of design problems using one approach. A numerical algorithm to solve these problems is based on particle swarm optimization. Various results of numerical experiments are discussed in order to find the most effective designs. The findings obtained in this study describe a broad set of specific easy-to-manufacture structures that have the highest cloaking or shielding performance in the class of layered shells.

  • 3.
    Andrews, Paul
    et al.
    Stockholms universitet.
    Palm Kaplan, Kristina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    PISA, TIMSS and Swedish students' knowledge of linear equations: A 'telling' case of a system fixing something that may not be broken2020In: Annales Universitates Paedagogicae Cracoviensis. Studia ad Didacticam Mathematicae Pertinentia, ISSN 2080-9751, Vol. 12, p. 5-29Article in journal (Refereed)
    Abstract [en]

    In this paper, we construct a 'telling' case to highlight a problematic inconsistency between the results of international large-scale assessments (ILSAs) and other studies of Swedish students' knowledge of linear equations. In this context, a 'telling' case, based on the scrutiny of appropriately chosen cases, is presented as a social science counter-example to the prevailing view that ILSAs' assessments are not only valid but should underpin systemic reform. Our 'telling' case comparison of the different forms of study shows that Swedish students, in contrast with the summative assertions of the different ILSAs, have a secure and relational understanding of linear equations that persists into adulthood. We conclude with a cautionary message for the curriculum authorities. 

  • 4.
    Asami-Johansson, Yukiko
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Conditions and constraints for transferring Japanese structured problem solving to Swedish mathematics classroom2021In: Recherche en Didactique des Mathématiques, ISSN 2728-2422, Vol. 41, no 3, p. 347-391Article in journal (Refereed)
    Abstract [en]

    This case study investigates to what extent a specific theory and a practice of mathematics teaching − the Japanese structured problem solving, as formulated by K. Souma can be transferred and applied in a new context (Sweden). The analysis is based on tools from the anthropological theory of the didactic. It turns out that the Swedish teacher can manage the didactic techniques, which are supported by a didactic theory shared within the community of Swedish teachers. However, there are common didactic techniques within the Japanese structured problem solving approach for which this is not the case, and which were indeed difficult to manage for the Swedish teacher. Among these were techniques related to bansho (blackboard organisation); letting the students formulate a kadai (derived task) of the lesson; and kikan-shido (monitoring students’ work to plan a subsequent whole-class discussion). Further, the paper provides an ecological analysis on the underlying conditions and constraints that brought about this phenomenon − a discrepancy concerning the didactic praxeologies of teachers. In Japan, teachers focus on the students’ personal development in the processes of the reflective and collective way of learning, while the Swedish teacher focuses more on individual student’s achievement of the knowledge.

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  • 5.
    Asami-Johansson, Yukiko
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Japanese Mathematics Teachers’ Professional Knowledge: International case studies based on praxeological analysis2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The thesis describes and studies the Japanese mathematics teachers’ professional knowledge and its dissemination. This theme is investigated in several concrete situations: the knowledge of teaching practice of school mathematics taught in the teacher education, the relation between the educational goals described in the national curriculum and concrete teaching methods discussed among the Japanese lower secondary teachers in service. The thesis investigates also critical phenomena, which arise in an attempt to transfer the Japanese teaching practice in a different teaching context.

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  • 6.
    Asami-Johansson, Yukiko
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics. University of Copenhagen, Copenhagen, Denmark.
    The Didactic Notion of “Mathematical Activity” in Japanese Teachers’ Professional Scholarship: A case study of an open lesson2021In: REDIMAT - Journal of Research in Mathematics Education, E-ISSN 2014-3621, Vol. 10, no 1, p. 88-112Article in journal (Refereed)
    Abstract [en]

    This paper investigates how Japanese mathematics teachers produce and share didactic knowledge together. It is a case study of a post-lesson reflection meeting so-called open lesson. The crucial idea of this study is the dialectic between the specific and generic level of foci of the participants’ reflections about the observed teaching practice; namely, about applied teacher’s specific didactic technique for achieving a specific mathematical goal, and more general pedagogical issues such as realisation of the objectives of mathematics education. This dialectic is mediated by the meso-level notion of mathematical activity, described in the guidelines for Japanese national curriculum. The application of the scale of levels of didactic co-determination, provided by the anthropological theory of the didactic into the analysis shows in what way the dialectic interplay between the teachers’ comments with focus of the specific and generic levels influences the development and establishment of the Japanese teachers’ shared professional scholarship.  

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  • 7.
    Asami-Johansson, Yukiko
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Attorps, Iiris
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics. Univ Gavle, Gavle, Sweden..
    Applying the structured problem solving in teacher education in Japan - A case study2015In: PROCEEDINGS OF THE NINTH CONFERENCE OF THE EUROPEAN SOCIETY FOR RESEARCH IN MATHEMATICS EDUCATION (CERME9) / [ed] Krainer, K; Vondrova, N, CHARLES UNIV, FAC EDUC , 2015, p. 2741-2747Conference paper (Refereed)
    Abstract [en]

    In this paper, we examine the implementation of a Japanese teacher educators' lesson, where he applies and, at the same time, inform the students about "structured problem solving". We describe a specific lesson titled "Quantity and Measurement" for elementary school teacher students and we show how the educator make the students aware of the didactic transposition of the material and how he makes the students experience and learn about applying "structured problem solving" in practice. We also show how the Japanese curriculum influences the scale of the mathematical praxeology to be learned and how the students are given opportunities to develop their insight into the PCK during their education in mathematics.

  • 8.
    Asami-Johansson, Yukiko
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Attorps, Iiris
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Japanese and Swedish Mathematics Teacher Educators’ Pedagogical Content Knowledge: An Institutional Perspective2019In: Educaçao Matemática Pesquissa, ISSN 1983-3156, Vol. 21, no 4, p. 157-170Article in journal (Refereed)
    Abstract [en]

    The aim of this paper is to investigate which kind of conditions and constraints affect Japanese and Swedish teacher educators’ pedagogical content knowledge (PCK). We analyse the praxeologies of the lessons in which the educators teach area determination. Our study shows that the Japanese teacher educators’ PCK are more explicitly shared by the community of the teacher educators compared to the Swedish counterpart. Also, the detailed Japanese curriculum and the structured problem solving approach promote to illustrate how to construct rich mathematical and didactical organisations for prospective teachers.

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  • 9.
    Asami-Johansson, Yukiko
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Attorps, Iiris
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Laine, Anu
    University of Helsinki, Helsinki, Finland.
    Comparing the practices of primary school mathematics teacher education Case studies from Japan, Finland and Sweden2017In: PROCEEDINGS OF THE TENTH CONGRESS OF THE EUROPEAN SOCIETY FOR RESEARCH IN MATHEMATICS EDUCATION (CERME10) / [ed] Dooley, T.; Gueudet, G., Dublin, 2017, p. 1602-1609Conference paper (Refereed)
    Abstract [en]

    In this study, we have observed three different teacher educators’ lessons, concerning area determination of polygons in primary school teacher training courses in Japan, Finland and Sweden. The aim of this paper is to investigate the main elements of the lessons and to compare the differences between the countries. We focus on how the teacher educators relate the didactic construction of the lessons for prospective teachers to the school mathematical and didactical organisations by applying Chevallard’s anthropological theory of the didactic (ATD). The analysis shows how the curricula and the different traditions of teaching practice in each country influence the mathematical and didactical construction of the lessons.

  • 10.
    Asami-Johansson, Yukiko
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics. Department of Science Education, University of Copenhagen, Copenhagen, Denmark.
    Attorps, Iiris
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Winsløw, C.
    Department of Science Education, University of Copenhagen, Copenhagen, Denmark.
    Comparing mathematics education lessons for primary school teachers: case studies from Japan, Finland and Sweden2020In: International Journal of Mathematical Education in Science and Technology, ISSN 0020-739X, E-ISSN 1464-5211, Vol. 51, no 5, p. 688-712Article in journal (Refereed)
    Abstract [en]

    The aim of this paper is to investigate and compare lessons given in primary school teacher education in Japan, Finland and Sweden. We analyse one lesson from each country and compare them using a common framework. Chevallard’s anthropological theory of the didactic (ATD) is used to frame this analysis and in particular to model teacher educators' didactic organization of the lessons. The focus is on how the didactic organizations of the teacher educators relate to the mathematical and didactic organizations of primary school. Based on official documents and viewpoints of the teacher educators, we also discuss how the contents and descriptions of the national curricula, and the different traditions of the teaching practices in each country, influence the didactic organizations found in the lessons. 

  • 11.
    Attorps, Iiris
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Kellner, Eva
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Biology.
    Ett helhetsgrepp för likvärdig skola2021In: Nämnaren : tidskrift för matematikundervisning, ISSN 0348-2723, no 3, p. 35-39Article in journal (Other (popular science, discussion, etc.))
  • 12.
    Backman, Mathilda
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Se mig!: En studie om matematiskt särskilt begåvade elever2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med studien är att utforska vilka uppfattningar lågstadielärare har av matematiskt särskilt begåvade elever, samt undersöka vilka arbetssätt lärare har för att motivera och stimulera de här eleverna i matematik. Studien har en metod med kvalitativ ansats med en fenomenografisk och fenomenologisk inriktning. Datainsamlingsmetoden för studien är intervjuer. Fyra lärare intervjuades och de är alla något så när överens om att matematiskt särskilt begåvade elever skiljer sig från andra elever, samt på vilket sätt de gör det. Lärarnas uppfattningar av matematiskt särskilt begåvade elever överensstämmer även med tidigare forskning gällande ämnesområdet. Samtliga lärares arbetssätt innehåller extra anpassningar för de här eleverna och största skillnaden som kunnat urskiljas mellan arbetssätten är huruvida de även innehåller särskilt stöd. Till viss del överensstämmer dessa uppfattningar även med tidigare forskning då det även där råder oenigheter om matematiskt särskilt begåvade elever ska differentieras eller inte.

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  • 13.
    Berglund, Jessica
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Vill du spela bingo med mig?: En studie med laborativt material för att utveckla elevers kunskaper om positionssystemet2019Independent thesis Advanced level (degree of Master (Two Years)), 240 HE creditsStudent thesis
    Abstract [sv]

    Studiens syfte är att med hjälp av en learning study med förtest och eftertest undersöka elevers förkunskaper om positionssystemet samt om elever genom laborativt material kan fördjupa sina kunskaper om positionssystemet. Studiens teoretiska utgångspunkt är hämtad från variationsteorin. Att arbeta med ett laborativt material möjliggör för eleverna att utveckla en utökad förståelse för positionssystemet med basen 10. En av slutsatserna från denna studie är att ett variationsteoretiskt perspektiv på undervisningen underlättar lärandet.

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    Vill du spela bingo med mig?
  • 14.
    Bergqvist, Charlotte
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Vad vill de att jag ska göra?: Om språkbruket i matematikläroboken2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Forskning och studier visar att behärskandet av matematikspråk är viktigt för kunskapsutvecklingen inom matematik samt att eleven riskerar att misslyckas om hen inte förstår begreppen. Studier har också visat att textbaserade uppgifter riskerar att skapa hinderför elever då språket kan vara svårbegripligt. Samtidigt visar undersökningar att användandet av läromedel dominerar matematikklassrummet och att tyst räkning i boken är ett vanligt arbetssätt. Uppsatsens syfte var att granska språkbruket i två upplagor av tre olika läromedels texter om geometri med kvantitativ innehållsanalys. Förekomsten av vardagsspråk, skolspråk och matematikspråk kartlades och resultatet användes för att undersöka förekomsten av ord och begrepp med dubbel betydelse. Resultaten visar att runt 3-4 % av texten innehåller ord eller begrepp med dubbel betydelse som skulle kunna skapa hinder för elever ispråksvårigheter. Genom att analysera matematikläromedel kan både lärarstudenter och praktiserande lärare förekomma eventuella språkförbistringar och istället bidra till att elever utvecklas både språkligt och matematiskt.

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  • 15.
    Bergström, Jonas
    et al.
    Stockholms Univ.
    Bergvall, Olof
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics. Uppsala universitet, Matematiska institutionen.
    The equivariant Euler characteristic of $\mathcal{A}3[2]$2020In: Annali della Scuola Normale Superiore di Pisa (Classe Scienze), Serie V, ISSN 0391-173X, E-ISSN 2036-2145, Vol. 20, no 4, p. 1345-1357Article in journal (Refereed)
    Abstract [en]

    We compute the weighted Euler characteristic, equivariant with respect to the action of the symplectic group of degree six over the field of two elements, of the moduli space of principally polarized Abelian threefolds together with a level two structure.Keywords

  • 16.
    Bergvall, Olof
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Cohomology of complements of toric arrangements associated with root systems2022In: Research in the Mathematical Sciences, ISSN 2522-0144, Vol. 9, no 1, article id 9Article in journal (Refereed)
    Abstract [en]

    We develop an algorithm for computing the cohomology of complements of toric arrangements. In the case a finite group ΓΓ is acting on the arrangement, the algorithm determines the cohomology groups as representations of ΓΓ. As an important application, we determine the cohomology groups of the complements of the toric arrangements associated with root systems of exceptional type as representations of the corresponding Weyl groups.

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  • 17.
    Bergvall, Olof
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    On the cohomology of the space of seven points in general linear position2020In: Research in Number Theory, ISSN 2522-0160, Vol. 6, article id 48Article in journal (Refereed)
    Abstract [en]

    We determine the cohomology groups of the space of seven points in general linear position in the projective plane as representations of the symmetric group on seven elements by making equivariant point counts over finite fields. We also comment on the case of eight points.

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  • 18.
    Billström, Linda
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Matematikläxors vara eller inte vara - lågstadielärare berättar sitt perspektiv2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med examensarbetet är att undersöka ifall lågstadielärare ger sina elever läxor i matematik och vad deras bakomliggande syfte är med att ge eller inte ge läxa. Examensarbetet undersöker även vilka typer av läxor i matematik som lärarna ger samt vad lärarna anser att de olika läxornas funktion är. För att kunna ta reda på lärares åsikter om läxor i matematik användes strukturerade intervjuer med utgångspunkt från de teoretiska ramverken som lyfts i examenarbetet.

     

    Resultaten visar att lärarnas främsta syfte är att eleverna ska öva och repetera för att befästa kunskap eftersom tiden i skolan inte räcker till. Men även att eleverna ska lära sig ta ansvar och få studievana inför framtiden, stärka relationer mellan vårdnadshavare och barn samt skapa kommunikationskanal med vårdnadshavarna. De läxor som använts är öva- eller repetitionsläxa med samma intention som syftet och komma ikapp läxor för att eleverna inte ska hamna efter i undervisningsplaneringen.

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  • 19.
    Blank, Jonathan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Motivation till matematik: En kvalitativ studie om hur elever i årskurs 4–6 kan motiveras i matematikundervisningen ur ett lärarperspektiv2019Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna studie är att undersöka hur lärare arbetar med att motivera elever i årskurs 4–6 i matematik. För att undersöka detta genomfördes klassrumsobservationer och semistrukturerade intervjuer med tre verksamma lärare i årskurs 4–6. Studiens resultat visar att en hög motivation hos eleverna skapas av tydliga strukturer i klassrummet, att läraren synliggör målen för eleverna, att läraren varierar sina arbetssätt och undervisningsformer samt att eleven tar ansvar för sitt eget lärande. 

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  • 20.
    Cappello, Barbara
    et al.
    Politecnico di Torino, Torino, Italy.
    Shestopalov, Yury
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Matekovits, Ladislau
    Politecnico di Torino, Torino, Italy.
    Analysis of the surface impedance of a sinusoidally modulated metasurface2019In: 2019 International Conference on Electromagnetics in Advanced Applications (ICEAA), IEEE, 2019, p. 0075-0077Conference paper (Refereed)
    Abstract [en]

    Metasurfaces have been extensively exploited in recent years for mantle cloaking applications. In this type of problems it is of fundamental importance to determine the connection between the metasurface geometrical parameters and the realised value of surface impedance, in order to properly design the metasurface. In this paper the surface impedance of a non homogeneous metasurface, based on a sinusoidally modulated metallic pattern is analysed.

  • 21.
    Cronhjort, Mikael
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics. KTH.
    Bengmark, Samuel
    Chalmers tekniska högskolan; Göteborgs universitet.
    Kann, Linda
    KTH.
    Kann, Viggo
    KTH.
    Leadership and Pedagogical Skills in Computer Science Engineering by Combining a Degree in Engineering with a Degree in Education2020In: 2020 IEEE Frontiers in Education Conference (FIE), IEEE , 2020, p. 1-9Conference paper (Refereed)
    Abstract [en]

    In this full paper on innovative practice, we describe and discuss findings from dual degree study programmes that combine a master's degree in engineering with a master's degree in education. This innovative study programme design has emerged in Sweden due to an alarming demand for more Upper Secondary School teachers in STEM subjects. Studies on alumni from these programmes indicate that the graduates are highly appreciated not only as teachers in schools, but also in business and industry, e.g. in roles as IT consultants and computer science engineers. Data indicate that the breadth of the combined education, and especially leadership and pedagogical skills, are important factors for these graduates' success as engineers.

  • 22.
    Cronhjort, Mikael
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Hagemann-Jensen, Maria
    Avstånd med olika metriker2021In: Nämnaren : tidskrift för matematikundervisning, ISSN 0348-2723, no 1, p. 44-50Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    Författarna beskriver en lektion om avståndsberäkningar med olika metrikersom de tror att kan vara inspirerande både för elever och matematiklärare pågymnasiet. Lektionen utvecklades i ett samarbete mellan fem lärare underKleindagarna i januari 2020. 

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  • 23.
    Cronhjort, Mikael
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Nobuoka, Jakob
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Management, Industrial Design and Mechanical Engineering, Industrial Management.
    Ängskog, Per
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Electronics.
    Haga, Andreas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Mårtensson, Gunilla
    Efforts to improve attractiveness of lower level engineering education (concept)2022In: SEFI 2022 - 50th Annual Conference of the European Society for Engineering Education, Proceedings, 2022, p. 1104-1112Conference paper (Refereed)
    Abstract [en]

    There are nine study programmes awarding the degree bachelor in engineering (högskoleingenjör) at the University of Gävle. Some of these have only a few applicants, even though the graduates are appreciated by a relatively large regional primary and secondary sector industry. A major revision of the programmes is planned. One objective is to increase the attractiveness of the programmes. In the revised programmes, students are proposed to study most courses together during the first year of study, even if they belong to different engineering specializations. This is intended to improve the study environment. Students in programmes with low numbers of applicants will become part of a richer and livelier student collective. However, the attractiveness could further be problematized by asking to whom higher education is attractive. A special focus will be on increasing the admission of students from groups in society that have been underrepresented in higher education. More specifically this may be linked to individual factors such as the educational level of parents, family income, immigrational background and geography. There may also be societal explanations in traditions of gendered professions. Engineering programmes, and especially some of the specializations at the university, are dominated by male students. This study focuses on how universities can take action to further increase the attractiveness of the engineering programmes, with a special regard to groups that are known to be underrepresented among the students.

  • 24.
    Ekvall, Johanna
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Särskild begåvning: En studie om lärares kunskap och erfarenheter om särskild begåvning i matematik2021Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Enligt undersökningar som Skolverket har genomfört är cirka fem procent i den svenska skolan särskilt begåvade. Syftet med examensarbetet är att undersöka hur undervisningen anpassas för särskilt begåvade elever i matematik utifrån styrdokument, erfarenheter och kunskaper. Undersökningen för studien bygger på en kvalitativ metod utifrån intervjuer av lärare som har lång erfarenhet i att undervisa elever i matematik. Det teoretiska ramverket för studien bygger på den sociokulturella teorin utifrån Vygotskijs tankar om lärande där lärandet grundas i den sociala interaktionen mellan olika individer. Studiens resultat visar att lärare främst använder två olika metoder vid undervisningen av eleverna samt att lärarna individanpassar undervisningen för att de särskilt begåvade eleverna ska nå nästa kunskapsnivå. Resultatet visar även att det finns både motiverade samt omotiverade särskilt begåvade elever vilket är viktigt som lärare att vara medveten om.

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  • 25.
    Ellmer, Anton
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Digitala verktyg i matematikundervisningen: Kan de erbjuda möjligheter som analoga arbetsätt inte kan?2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med detta arbete är att undersöka om digitala verktyg kan erbjuda matematikundervisningen något som gör den bättre som analoga verktyg inte kan erbjuda. För att undersöka det genomfördes intervjuer med 10 lärare som har lärarlegitimation inom matematik och jobbar på lågstadium i Sverige. I resultat framkommer att digitala verktyg kan erbjuda mervärden till matematikundervisningen som inte går att tillgå om lärare arbetar analogt. Några av de mervärdena handlar om individanpassningar, matematikgenomgångar och gamification. Det framkommer även att förutsättningarna för att bedriva undervisningen med hjälp av digitala verktyg är otillräckliga i den mån att de digitala enheterna inte räcker till en hel klass samt att skicket på de digitala enheterna är dåligt. Det framkommer även att lärarna som deltog i studien knappt har någon utbildning gällande användande av digitala verktyg i undervisningen.

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  • 26.
    Ericson, Syréne
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Hur tolkar lärare formativ bedömning?: Fallstudie utifrån lärares tillämpning av formativ bedömning i undervisningen i matematik2021Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna undersökning är att studera hur matematiklärare uppfattar formativ bedömning, hur mycket stöd de får och hur lärare använder formativ bedömning i sin matematikundervisning. Undersökningen utförs på en skola som uttalar sig arbeta utifrån Dylan Wiliam och Helen Timpanys forskning om kollegialt lärande med hjälp av handboken av Wiliam och Leahy (2015). För att uppnå syftet med undersökningen så utfördes lektionsobservationer samt kvalitativa intervjuer med lärarna, rektor och samtalsansvarig för skolan. Resultatet visar att lärarna använder sig av olika metoder och tekniker inom den pedagogiska reformen formativ bedömning. Lärarna känner att de fått stöd ifrån sin ledning men att det varit svårt att arbeta med formativ bedömning på grund av att de har varit stort utbyte på kollegor. En slutsats är att oavsett hur mycket stöd och expertis som lärarna får så är det i slutänden upp till hur involverad läraren själv vill vara och vill utvecklas.

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  • 27.
    Esterov, Alexander
    et al.
    HSE University, Moscow, Russia.
    Lang, Lionel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics. Stockholms universitet.
    Braid monodromy of univariate fewnomials2021In: Geometry and Topology, ISSN 1465-3060, E-ISSN 1364-0380, Vol. 25, no 6, p. 3053-3077Article in journal (Refereed)
    Abstract [en]

    Let Cd⊂Cd+1 be the space of nonsingular, univariate polynomials of degree d. The Viète map V:Cd→Symd(C) sends a polynomial to its unordered set of roots. It is a classical fact that the induced map V∗ at the level of fundamental groups realises an isomorphism between π1(Cd) and the Artin braid group Bd. For fewnomials, or equivalently for the intersection C of Cd with a collection of coordinate hyperplanes in Cd+1, the image of the map V∗:π1(C)→Bd is not known in general.

    We show that the map V∗ is surjective provided that the support of the corresponding polynomials spans Z as an affine lattice. If the support spans a strict sublattice of index b, we show that the image of V∗ is the expected wreath product of Z∕bZ with Bd∕b. From these results, we derive an application to the computation of the braid monodromy for collections of univariate polynomials depending on a common set of parameters.

  • 28.
    Esterov, Alexander
    et al.
    HSE University, Russia.
    Lang, Lionel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Sparse polynomial equations and other enumerative problems whose Galois groups are wreath products2022In: Selecta Mathematica, New Series, ISSN 1022-1824, E-ISSN 1420-9020, Vol. 28, no 2, article id 22Article in journal (Refereed)
    Abstract [en]

    We introduce a new technique to prove connectivity of subsets of covering spaces (so called inductive connectivity), and apply it to Galois theory of problems of enumerative geometry. As a model example, consider the problem of permuting the roots of a complex polynomial f(x)=c0+c1xd1+⋯+ckxdkf(x)=c0+c1xd1+⋯+ckxdk by varying its coefficients. If the GCD of the exponents is d, then the polynomial admits the change of variable y=xdy=xd, and its roots split into necklaces of length d. At best we can expect to permute these necklaces, i.e. the Galois group of f equals the wreath product of the symmetric group over dk/ddk/d elements and Z/dZZ/dZ. We study the multidimensional generalization of this equality: the Galois group of a general system of polynomial equations equals the expected wreath product for a large class of systems, but in general this expected equality fails, making the problem of describing such Galois groups unexpectedly rich.

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  • 29.
    Fodor Broman, Georgeta
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Hur ”bråkar” vi bäst i skolan?: En studie kring den analoga och digitala matematikundervisningen i bråk2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I denna studie undersöks vilka analoga och digitala resurser som används av lärare i bråkundervisningen samt syftet med användningen av det specifika materialet. Vidare jämför studien det digitala och analoga materialets påverkan på elevernas resultat i bråkförståelse och klassrumsaktivitet. Studien besvarar de två frågeställningar, dels genom intervjuer med fem lärare kring användning av resurser i bråkundervisning samt genom fyra klassobservationstillfällen med följande eftertest av sammanlagt 14 elever från årskurs 5. Teorierna och metoderna som används för insamling av data och analys är variationsteorin, TPACK modellen, delvis learning study och det lärandeobjektet som studien fokuserar på är förlängning/förkortning av bråkform samt addition till helhet. Studien visar att lärare kompletterar det analoga materialet med digitala resurser med syfte att variera undervisningen och anpassa den till samhällets utveckling; de ser fördelar med digital teknik men även nackdelar. Elevernas testresultat tycks inte påverkas av valet av resurser, men klassrumsaktiviteten blir livligare vid användningen av digital teknik.  Det som tycks vara viktigt för en god undervisning och lyckat lärande är att lärare får möjlighet att välja fritt och anpassa material utifrån syftet med varje enskild lektion. I det avseende är det viktigt att lärarna har kunskap om digital teknik och stöd i kollegialt lärande och utbildning.

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  • 30.
    From, Sofia
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    ”Många behöver ta i och plocka med material för att det ska klicka i huvudet”: En undersökning om lärarens användning av laborativt material inom matematik för att öka elevernas förståelse och kunskap2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Studiens syfte var att undersöka den laborativa matematikens del i undervisningen. Det undersökningen ville ta reda på var hur laborativt material används inom matematik samt till vilket syfte det används. Undersökningen försökte även redogöra för vilket mervärde laborativ matematik skapar samt vilka möjligheter och utmaningar som finns med att implementera laborativt material. För att samla in material har undersökningen bestått av flera metoder såsom intervjuer, enkäter och en litteraturstudie. Resultatet visar att det finns olika syften med att använda laborativt material, där det främsta syftet är att konkretisera matematiken. Resultatet framhäver att eleverna får det lättare att abstrahera sina matematiska kunskaper om de får möjligheten att arbeta laborativt inledningsvis. Resultatet presenterar även olika möjligheter och utmaningar som en lärare behöver beakta vid implementeringen av laborativt material i undervisningen.

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  • 31.
    Froms, Denise
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Lärares uppfattningar om och arbetssätt rörande elevers matematiksvårigheter i de tidigare skolåren2020Independent thesis Advanced level (professional degree), 240 HE creditsStudent thesis
    Abstract [sv]

    Syftet med detta examensarbete är att undersöka hur lärare upptäcker elever med matematiksvårigheter och vad begreppet matematiksvårigheter betyder för lärarna. Studien undersöker även vilka metoder lärarna använder i arbetet med elever med matematiksvårigheter. För att besvara frågeställningarna har kvalitativa intervjuer genomförts med fem lärare. Data från studien har analyserats med hjälp av olika perspektiv på matematiksvårigheter samt utifrån ett kognitivistiskt perspektiv. Undersökningen visar att lärare upptäcker matematiksvårigheter genom att elever saknar de matematiska grunderna, har en bristande taluppfattning samt bristande kognitiva förmågor. Det mest använda arbetssättet i arbetet med elever med matematiksvårigheter är laborativa material där lek och lust var en viktig del av undervisningen. Praktiskt arbete framhölls av samtliga informanter som det mest användbara för elever med matematiksvårigheter.

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  • 32.
    Glimtsjö, Caroline
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Matematikundervisning för andraspråkselever: Lärares uppfattningar om likvärdighet och inkludering samt faktiska undervisningsstrategier2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Rapporter visar att elever med utländsk bakgrund presterar sämre i matematik än elever med svensk bakgrund i grundskolan. Vad det beror på är inte fastställt men socioekonomisk bakgrund, det svenska skolsystemets kapacitet för att utbilda elever med utländsk bakgrund och språkkunskaper i svenska diskuteras som möjliga orsaker (Skolverket, 2019). Syftet med detta examensarbete är att undersöka lärares uppfattningar om likvärdighet och inkludering i matematikundervisning när det gäller andraspråkselever, samt deras faktiska undervisningsstrategier. Fyra undervisande lärare i mellanstadiet och en studiehandledare intervjuades. Intervjuerna transkriberades och materialet analyserades sedan genom kodning och tematisering för att hitta gemensamma mönster men också skillnader. Resultatet visade att alla lärare uttrycker att andraspråkselever ska få den undervisning de behöver och att alla elever ska vara med. Hur lärare sedan arbetar i matematikundervisningen för att uppnå detta skiljer sig åt. Det var en lärare som stack ut i sin matematikundervisning då hen främst utgår från arbete i helklass och ett flerspråkigt förhållningssätt. Gemensamt för alla lärare är att de anser kartläggning, översättning och begreppsutveckling samt stöttning av andraspråkselever som särskilt viktigt i matematikundervisningen.

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  • 33.
    Grigoriadu, Hariklia
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Motivation till matematik: En kvalitativ studie om hur elever i årskurs F-3 kan motiveras i matematikundervisning ur ett lärarperspektiv.2021Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Följande kvalitativa studie fokuserar på att beskriva vilka faktorer lågstadielärare uttrycker har inverkan på elevers motivation att lära sig matematik och vad en lågstadielärare gör i sin matematikundervisning i syfte att motivera sina elever. Studien är inspirerad av etnografi och har två datainsamlingsmetoder. Datainsamlingsmetoderna består av observationer och semistrukturerade intervjuer. Resultatet i denna studie visar att lärarna uttrycker att elevnära ämnen, utmaningar, osäkerhet, nya material och lärares och föräldrars inställning har inverkan på elevernas motivation för att lära sig matematik. Lärarna uttrycker också att de använder sig av varierad undervisning för att motivera sina elever. Med hjälp av teorin om självbestämmande kan resultatet tolkas som att lärarna försökte öka elevernas inre och yttre motivation under sin undervisning. Lärarna uttrycker att eleverna blir motiverade av nya material och nya saker i sin matematikundervisning vilket de gör genom att öka elevernas yttre motivation och det är studiens bidrag.

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  • 34.
    Hernandez-Martinez, Paul
    et al.
    Swinburne University of Technology.
    Thomas, Stephanie
    Loughborough University.
    Viirman, Olov
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics. University of Agder.
    Rogovchenko, Yuriy
    University of Agder.
    "I'm still making dots for them": mathematics lecturers' views on their mathematical modelling practices2021In: International Journal of Mathematical Education in Science and Technology, ISSN 0020-739X, E-ISSN 1464-5211, Vol. 51, no 2, p. 165-177Article in journal (Refereed)
    Abstract [en]

    Using Cultural-Historical Activity Theory, we analyze lecturers’ views on the aims and teaching practices of mathematical modelling (MM) education in Norway and England. We aim to expose the tensions that exist within the activity of teaching MM at university, such as those between multiple, sometimes competing, aims for teaching MM, or between the lecturers’ professional identities and the structure of university degrees. Our conceptualization of these tensions might help lecturers consider how to overcome obstacles in their own contexts.

  • 35.
    Heyd-Metzuyanim, Einat
    et al.
    Technion, Israel Institute of Technology.
    Adler, Jill
    University of the Witwatersrand.
    Lavie, Irit
    Haifa University.
    Nachlieli, Talli
    Levinsky College.
    Tabach, Michal
    Tel Aviv University.
    Robertson, Sally-Ann
    Rhodes University.
    Graven, Mellony
    Rhodes University.
    Viirman, Olov
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Research Forum: Rituals and explorations in mathematical teaching and learning2019In: Proceedings: 43rd Annual Meeting of the International Group for the Psychology of Mathematics Education (Vol. 1) / [ed] Mellony Graven, Hamsa Venkat, Anthony A Essien and Pamela Vale, 2019, Vol. 1, p. 137-164Conference paper (Refereed)
  • 36.
    Ivanchenko, Igor
    et al.
    O.Ya. Usikov Institute for Radiophysics and Electronics of the National Academy of Sciences of Ukraine.
    Khruslov, Maxym
    O.Ya. Usikov Institute for Radiophysics and Electronics of the National Academy of Sciences of Ukraine.
    Popenko, Nina
    O.Ya. Usikov Institute for Radiophysics and Electronics of the National Academy of Sciences of Ukraine.
    Plakhtii, Vladimir
    O.Ya. Usikov Institute for Radiophysics and Electronics of the National Academy of Sciences of Ukraine.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Electronics.
    Shestopalov, Yury
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    A novel resonance method for determining the complex permittivity of local inclusions in a rectangular waveguide2020In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 31, no 9, article id 097001Article in journal (Refereed)
    Abstract [en]

    A novel resonance method for determining the complex permittivity of materials in the X-band is proposed. A distinctive feature of this method is that the sample under test, located in a radio-transparent isotropic and homogeneous dielectric matrix, is both a local inclusion and the excitation element of the resonance in the microwave module 'waveguide–dielectric matrix–inclusion'. The complex permittivity of an inclusion is determined by comparing the measured resonance frequency and quality factor with the computed database value. The permittivity and loss factor of microwave ceramics, natural granite and ferrite are investigated, as well as crystals of lead fluoride PbF2 doped with holmium trifluoride HoF3 and erbium fluoride ErF3 of different concentrations. The method allows the permittivity and loss tangent to be determined with uncertainties of 0.1% and 5%, respectively.

  • 37.
    Jerez-Hanckes, C.
    et al.
    Universidad Adolfo Ibáñez Diagonal Las Torres, Peñalolén, Santiago, 2700, Chile.
    Pettersson, Irina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Rybalko, V.
    B. Verkin Institute for Low Temperature Physics and Engineering of NASU, 47 Nauky Ave., Kharkiv, 61103, Ukraine.
    Derivation of cable equation by multiscale analysis for a model of myelinated axons2020In: Discrete and continuous dynamical systems. Series B, ISSN 1531-3492, E-ISSN 1553-524X, Vol. 25, no 3, p. 815-839Article in journal (Refereed)
    Abstract [en]

    We derive a one-dimensional cable model for the electric potential propagation along an axon. Since the typical thickness of an axon is much smaller than its length, and the myelin sheath is distributed periodically along the neuron, we simplify the problem geometry to a thin cylinder with alternating myelinated and unmyelinated parts. Both the microstructure period and the cylinder thickness are assumed to be of order ε, a small positive parameter. Assuming a nonzero conductivity of the myelin sheath, we find a critical scaling with respect to ε which leads to the appearance of an additional potential in the homogenized nonlinear cable equation. This potential contains information about the geometry of the myelin sheath in the original three-dimensional model. 

  • 38.
    Jerez-Hanckes, Carlos
    et al.
    Universidad Adolfo Ibáñez, Santiago, Chile.
    Martínez, Isabel A.
    Pontificia Universidad Católica de Chile, Santiago, Chile.
    Pettersson, Irina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Rybalko, Volodymyr
    Institute for Low Temperature Physics and Engineering, Kharkiv, Ukraine.
    Multiscale Analysis of Myelinated Axons2021In: SEMA SIMAI Springer Series, Springer , 2021, p. 17-35Chapter in book (Refereed)
    Abstract [en]

    We consider a three-dimensional model for a myelinated neuron, which includes Hodgkin–Huxley ordinary differential equations to represent membrane dynamics at Ranvier nodes (unmyelinated areas). Assuming a periodic microstructure with alternating myelinated and unmyelinated parts, we use homogenization methods to derive a one-dimensional nonlinear cable equation describing the potential propagation along the neuron. Since the resistivity of intracellular and extracellular domains is much smaller than the myelin resistivity, we assume this last one to be a perfect insulator and impose homogeneous Neumann boundary conditions on the myelin boundary. In contrast to the case when the conductivity of the myelin is nonzero, no additional terms appear in the one-dimensional limit equation, and the model geometry affects the limit solution implicitly through an auxiliary cell problem used to compute the effective coefficient. We present numerical examples revealing the forecasted dependence of the effective coefficient on the size of the Ranvier node

  • 39.
    Johansson, Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Öberg, Anders
    Uppsala University.
    Pollicott, Mark
    University of Warwick, Coventry, UK.
    Phase transitions in long-range Ising models and an optimal condition for factors of g-measures2019In: Ergodic Theory and Dynamical Systems, ISSN 0143-3857, E-ISSN 1469-4417, Vol. 39, no 5, p. 1317-1330Article in journal (Refereed)
    Abstract [en]

    We weaken the assumption of summable variations in a paper by Verbitskiy [On factors of g-measures. Indag. Math. (N.S.) 22 (2011), 315-329] to a weaker condition, Berbee's condition, in order for a one-block factor (a single-site renormalization) of the full shift space on finitely many symbols to have a g-measure with a continuous g-function. But we also prove by means of a counterexample that this condition is (within constants) optimal. The counterexample is based on the second of our main results, where we prove that there is a critical inverse temperature in a one-sided long-range Ising model which is at most eight times the critical inverse temperature for the (two-sided) Ising model with long-range interactions.

  • 40.
    Keczan, Kristina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Chevalley-Warnings sats om nollställemängder i projektiva rum över ändliga kroppar2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I detta arbete studeras de affina och projektiva rummen över ändliga kroppar för att vidare analysera polynom och nollställemängderna till dessa, över just ändliga kroppar. Djupgående kommer vi bland annat undersöka vilka ändliga kroppar som finns, studera polynom över dessa, definiera vektorrum och konstruera det projektiva rummet. Chevalley-Warnings sats kommer vara ett huvudresultat och bevisas grundligt. Vi kommer även fördjupa vår studie något genom att studera projektiv geometri över ändliga kroppar. De ändliga kropparnas egenskaper, konstruering av projektiva rum, homogenisering av polynom och beviset till Chevalley-Warnings sats kommer vara nyckelresultat. Vi illustrerar resultaten genom att studera nollställemängderna till några enklare polynom.

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  • 41.
    Kellner, Eva
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Biology.
    Attorps, Iiris
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    The school–university intersection as a professional learning arena: evaluation of a two-year action research project2020In: Teacher Development, ISSN 1366-4530, E-ISSN 1747-5120, Vol. 24, no 3, p. 366-383Article in journal (Refereed)
    Abstract [en]

    This article presents the evaluation of a two-year action research project in biology and mathematics teaching involving a primary school and a university in Sweden. The aim of the study was to contribute knowledge about a school–university intersection as a professional learning arena. The teachers’ conceptions about the project implementation, the impact on their learning, teaching practices and pupil learning were made explicit by focus group interview. The evaluation revealed that several motivating factors in this specific learning community – the relevance of the project and connection to the continuing education course, mentors from university, planning tools and time for collaboration – were critical for project implementation and for professional learning to occur. Furthermore, it indicated how teacher learning and teaching practices were related to pupil learning in the professional learning community. The results are also discussed in the light of new research on teachers’ work identity and self-reported health.

  • 42.
    Khulbe, Manisha
    et al.
    Ambedkar Institute of Advanced Communication Technologies and Research (AIACTR), Delhi, India.
    Tripathy, Malay Ranjan
    Amity School of Engineerng and Technology, Amity University, Noida, India.
    Parthasarathy, Harish
    Netaji Subhash Institute of Technology (NSIT), N. Delhi, India.
    Shestopalov, Yury
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Lagovsky, Boris
    Russian Technological University, MIREA, Moscow, Russia.
    Inverse Scattering and Imaging Using Second Order Optical Nonlinearities2019In: 2019 6th International Conference on Signal Processing and Integrated Networks, SPIN 2019, IEEE, 2019, p. 1086-1089Conference paper (Refereed)
    Abstract [en]

    In this paper a mathematical technique is developed to find the parameters of a medium in terms of its scattered electromagnetic fields. Optical nonlinearity plays an important role in finding the scattering parameters of a medium. Using perturbation theory and nonlinear inverse scattering techniques with first order, second order and third order optical nonlinearity we find scattered electromagnetic fields. Using error minimization techniques parameters are estimated in term of permittivity and permeability up to second order. © 2019 IEEE.

  • 43.
    Kimsis, Karlis
    et al.
    Riga Technical University, Riga, Latvia.
    Semenjako, Janis
    Riga Technical University, Riga, Latvia.
    Shestopalov, Yury
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Effectively Tunable Bandpass Waveguide Filter Based on Incorporation of Coupled Cylindrical Resonators Cut in Half2020In: Electrical control and communication engineering, ISSN 2255-9140, Vol. 16, no 2, p. 78-87Article in journal (Refereed)
    Abstract [en]

    A novel mechanically tunable waveguide dielectric filter is presented in this paper. The resonant structure of the filter is made of a rectangular waveguide cavity and an H-plane dielectric cylinder cut in half. The resonating frequency of the proposed structure can be significantly changed by moving two split cylinder parts. The coupling matrix synthesis technique is used to create the required bandpass filter. A drawback of the proposed structure is that the tuning process invokes a mismatch between the feeding structure and the filter. To overcome this drawback, the tuning screws between the coupling irises are used. A filter with the proposed geometry has a large frequency tuning range as well as relatively constant passband bandwidth.

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  • 44.
    Kimsis, Karlis
    et al.
    Riga Technical University.
    Semenjako, Janis
    Riga Technical University.
    Shestopalov, Yury
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Mechanically tunable coupled resonator waveguide bandpass filter2019In: 2019 IEEE Microwave Theory and Techniques in Wireless Communications (MTTW), 2019, Vol. 1, p. 52-56Conference paper (Refereed)
    Abstract [en]

    This paper proposes a novel mechanically tunable waveguide filter design, based on a coupled resonator topology. The resonator geometry consists of a rectangular waveguide cavity and a dielectric cylinder. Unlike conventional cylindrical resonators which are made out of a single part, here the cylinders are cut in half. By changing the distance between these two parts, the resonating frequency of the resonator can be changed, which allows for a tunable filter design. A filter using the proposed geometry has a large tuning bandwidth as well as relatively constant passband frequencies. The performance of the proposed filter is demonstrated by evaluating the filter using 3D simulation software CST Studio Suite.

  • 45.
    Kushnin, R.
    et al.
    Riga Technical University, Latvia.
    Kuzminovs, G.
    Riga Technical University, Latvia.
    Semenjako, J.
    Riga Technical University, Latvia.
    Shestopalov, Yury
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Novel high-sensitivity non-destructive technique for the measurement of permittivity of a low-loss dielectric slab in free space2019In: 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring), 2019, p. 1723-1731, article id 9017638Conference paper (Refereed)
    Abstract [en]

    In the present paper, the high-sensitivity technique for reducing the uncertainty of the free-space measurements of the real part of the permittivity of dielectric slab is proposed. The real part of the permittivity is extracted from the absolute value of the reflection coefficient measured by means of horn antenna. It is shown that making measurements for the slab under test (SUT) alone (original experimental model), in many cases results in large uncertainty because of low sensitivity of the model in the range of possible values of the real part of permittivity. The total measurement uncertainty depends on the slope of the measurement curve that can be used as a measure of the sensitivity of the model; consequently, to reduce it one has to increase the slope of the measurement curve that can be achieved by varying parameters of the model, such as the operating frequency or thickness of SUT. However, when the measurements are to be made in a non-destructive manner at a given frequency (in case of highly dispersive materials), neither frequency, nor thickness can be changed thus making it impossible to increase the slope of the measurement curve in the region of interest and, therefore, reduce the uncertainty. To overcome the problem we propose to extend the original model by introducing into it one or two auxiliary slabs (extended model) with known constitutive properties thereby extending the set of model parameters affecting the shape of the curve. Alternatively, with extended models one can achieve higher sensitivity without having to vary the frequency and thickness. Optimal choice of dimensions of auxiliary slab(s) is discussed in detail herein. The validity of the proposed method is verified through numerical experiments.

  • 46.
    Lagovsky, B. A.
    et al.
    Russian Technological University (MIREA), Moscow, Russia.
    Samokhin, A. B.
    Russian Technological University (MIREA), Moscow, Russia.
    Shestopalov, Yury V.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Regression Methods of Obtaining Angular Superresolution2019In: 2019 URSI Asia-Pacific Radio Science Conference (AP-RASC), New Dehli: IEEE, 2019, article id 8738539Conference paper (Refereed)
    Abstract [en]

    New methods of signal processing based on nonlinear regression methods are presented. They allow us to restore images of individual objects of group targets with superresolution at signal-to-noise ratios that are significantly lower than those provided by the known methods.

  • 47.
    Lagovsky, Boris
    et al.
    Russian Technological University MIREA.
    Samokhin, Alexander
    Russian Technological University MIREA.
    Shestopalov, Yury
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Angular superresolution based on a priori information2021In: Radio Science, ISSN 0048-6604, E-ISSN 1944-799X, Vol. 56, no 3, article id e2020RS007100Article in journal (Refereed)
    Abstract [en]

    The results of theoretical studies and mathematical modeling indicate the possibility of obtaining the angular superresolution and its limits by using algebraic methods of imaging. The necessary algorithms are created on the basis of solution to inverse problems. The limiting levels of the achieved angular superresolution are found depending on the signal‐to‐noise ratio for objects of various types. A number of specific advantages of the method are shown as applied to the solution of two‐dimensional problems. Capabilities of the method are illustrated by examples. High performance of the proposed approach allows one to use it in real time when scanning and tracking targets.

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  • 48.
    Lan, Yihong
    et al.
    Suntar Research Institute, Singapore, Singapore.
    Yin, Li
    Karolinska institutet.
    Wang, Xiaoqin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Dynamics of COVID-19 progression and the long-term influences of measures on pandemic outcomes2022In: Emerging Themes in Epidemiology, E-ISSN 1742-7622, Vol. 19, article id 10Article in journal (Refereed)
    Abstract [en]

    The pandemic progression is a dynamic process, in which measures yield outcomes, and outcomes in turn influence subsequent measures and outcomes. Due to the dynamics of pandemic progression, it is challenging to analyse the long-term influence of an individual measure in the sequence on pandemic outcomes. To demonstrate the problem and find solutions, in this article, we study the first wave of the pandemic—probably the most dynamic period—in the Nordic countries and analyse the influences of the Swedish measures relative to the measures adopted by its neighbouring countries on COVID-19 mortality, general mortality, COVID-19 incidence, and unemployment. The design is a longitudinal observational study. The linear regressions based on the Poisson distribution or the binomial distribution are employed for the analysis. To show that analysis can be timely conducted, we use table data available during the first wave. We found that the early Swedish measure had a long-term and significant causal effect on public health outcomes and a certain degree of long-term mitigating causal effect on unemployment during the first wave, where the effect was measured by an increase of these outcomes under the Swedish measures relative to the measures adopted by the other Nordic countries. This information from the first wave has not been provided by available analyses but could have played an important role in combating the second wave. In conclusion, analysis based on table data may provide timely information about the dynamic progression of a pandemic and the long-term influence of an individual measure in the sequence on pandemic outcomes.

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    fulltext
  • 49.
    Lang, Lionel
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics. Department of Electrical Engineering, Mathematics and Science , University of Gävle , 80176 Gävle , Sweden.
    Renaudineau, Arthur
    Laboratoire Paul Painlevé , Université de Lille , CNRS, UMR 8524, 59000 Lille , France.
    Patchworking the Log-critical locus of planar curves2022In: Journal für die Reine und Angewandte Mathematik, ISSN 0075-4102, E-ISSN 1435-5345, Vol. 792, p. 115-143Article in journal (Refereed)
    Abstract [en]

    We establish a patchworking theorem à la Viro for the Log-critical locus of algebraic curves in (C∗)2(ℂ∗)2 . As an application, we prove the existence of projective curves of arbitrary degree with smooth connected Log-critical locus. To prove our patchworking theorem, we study the behaviour of Log-inflection points along families of curves defined by Viro polynomials. In particular, we prove a generalisation of a theorem of Mikhalkin and the second author on the tropical limit of Log-inflection points.

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  • 50.
    Lang, Lionel
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics.
    Tyomkin, Ilya
    Ben-Gurion University of the Negev, Israel.
    A note on the Severi problem for toric surfaces2023In: Mathematische Annalen, ISSN 0025-5831, E-ISSN 1432-1807, Vol. 385, p. 1677-1705Article in journal (Refereed)
    Abstract [en]

    In this note, we make a step towards the classification of toric surfaces admitting reducible Severi varieties. We provide two families of toric surfaces admitting reducible Severi varieties. The first family is general, and is obtained by a quotient construction. The second family is exceptional, and corresponds to certain narrow polygons, which we call kites. We introduce two types of invariants that distinguish between the components of the Severi varieties, and allow us to provide lower bounds on the numbers of the components. The sharpness of the bounds is verified in some cases, and is expected to hold in general for ample enough linear systems. In the appendix, we establish a connection between the Severi problem and the topological classification of univariate polynomials.

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