| 1. |
- Nyström, Peter, 1959, et al.
(författare)
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Hur samstämmiga är svenska styrdokument och nationella prov med ramverk och uppgifter i TIMSS Advanced 2015?
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- TIMSS Advanced (Trends in Mathematics and Science Study ) är en internationell studie som undersöker gymnasieelevers kunskaper i avancerad matematik och fysik. TIMSS Advanced har genomförts tre gånger, 1995, 2008 och 2015, och Sverige har deltagit varje gång. I 2015 års studie deltog svenska elever i årskurs 3 på naturvetenskaps- och teknikprogrammet som slutfört eller håller på att slutföra kursen matematik 4 respektive fysik 2. Studien ger möjlighet att analysera förändringar i motsvarande elevgruppers kunskaper över tid inom dessa områden, men också möjlighet att jämföra svenska resultat med resultat från andra länder. TIMSS Advanced 2015 har genomförts av Skolverket i samarbete med Nationellt Centrum för Matematikutbildning (NCM) vid Göteborgs universitet. Skolverket har sammanställt en nationell huvudrapport med resultaten från TIMSS Advanced 2015. En viktig utgångspunkt för tolkning och analys av resultaten är att veta i vilken utsträckning svenska elever fått möjlighet att lära sig det som prövas i TIMSS Advanced. I denna rapport analyseras därför samstämmigheten mellan TIMSS Advanced 2015 och svenska ämnesplaner, nationella prov och bedömningsstöd. Mot bakgrund av ämnenas kopplingar mellan varandra genomförs också en analys som särskilt fokuserar på inslaget av matematik i fysikuppgifterna.
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| 4. |
- Attorps, Iiris
(författare)
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Uppfattningar hos lärare av ekvationsbegreppet
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med min studie är att beskriva hur matematiklärare uppfattar begreppet ekvation. Min målsättning är också att undersöka lärarnas erfarenheter av ekvationsinlärning från grundskolan till universitetsnivån. Tio lärare från grundskolans högstadium har deltagit i undersökningen. Fem är nyutexaminerade lärare med mindre än ett års yrkeserfarenhet. Data i undersökningen samlades in genom enkäter och intervjuer. Undersökningsresultat analyserades genom fenomenografisk metod. Resultatet pekar på att lärarnas uppfattningar av ekvationsbegreppet avviker från den formella begreppsdefinitionen. De känner osäkerhet inför matematiska symboler, bokstavsuttryck och lösningsprocedurer. Deras skolerfarenheter visar att de har använt största delen av tiden till att utveckla algoritmiska färdigheter istället för matematisk förståelse.
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| 5. |
- Bonner, Richard
(författare)
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Operators that coerce the surjectivity of convolution
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Considered are operators that leave the set of non-invertible (in the sense of Ehrenpreis) distributions stable. They simultaneously generalise the operation of convolution by a distribution with compact support and the operation of multiplication by a real analytic function; they are here called pseudo-convolutions since they also generalise pseudo-differential operators. (It is shown that the elliptic real analytic pseudo-differential operators leave both the non-invertible and the invertible distributions invariant.) But when the condition of real-analyticity is relaxed, such operators may map a non-invertible distribution to one invertible -- given that the invertibility in both cases concerns the same function space. By varying the space, however, one can measure the 'loss of non-invertibily' that a non-analytic perturbation may introduce. This phenomenon is here studied using the Beurling classes of functions and measuring the regularity of operator symbols in the Denjoy-Carleman sense; the Gevrey case turns out particularly simple.
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| 6. |
- Funcke, Alexander, et al.
(författare)
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Biased perception may trump rational intention: Most people think they are less corrupt than average
- 2015
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Ingår i: SSRN Electronic Journal. - : Elsevier BV. - 1556-5068.
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- From a game theoretic point of view, a social norm can sometimes be considered as a Nash equilibrium in a coordination game. Here we point out a psychological reason why such a social norm might erode, even if it is beneficial and agents have rational intentions. The reason is a well-established bias in interpersonal perception, the better-than-average effect. Psychological research on this bias has mainly focused on skills and personality attributes, rather than normative behavior. In a series of online surveys, we demonstrate that the better-than-average effect applies also to judgments of the likelihood to engage in petty corruption, a very important domain of social norms. We conclude that this psychological bias may be a factor that contributes to the difficulty of establishing noncorruption.
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| 7. |
- Holm, Åsa, 1984-
(författare)
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A Tailored Branch-and-Bound Method for Optimizing the Dwelling Time Pattern and Catheter Positioning in HDR Brachytherapy
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- High dose-rate (HDR) brachytherapy is one type of treatment for prostate cancer, in which a radioactive source is moved through catheters implanted into the prostate. For each patient, a unique treatment plan is constructed. This plan determines for example the catheter positioning and the dwelling time pattern, that is, where and for how long the source should stop.Mathematical optimization methods are frequently used to find high-quality dwelling time patterns. However, choosing the catheter positioning is usually done without any aid of mathematical optimization methods. Researchers have recently suggested some optimization models for catheter positioning, and also heuristics for solving them. However, there are no available methods for finding the optimal solution of these models within a clinically acceptable time frame.In this paper we present the foundation for a branch-and-bound method that has been tailored to the catheter positioning problem. Tests show that this tailored branch-and-bound method has some promising features, for example that the dual bound is improved faster than when using a standard branch-and-bound method. But the tests also show that further research is required to develop it into a method that can find the optimal solution fast enough.
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- Ivanenko, Yevhen, et al.
(författare)
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Quasi-Herglotz functions and convex optimization
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We introduce the set of quasi-Herglotz functions and demonstrate that it has properties useful in the modeling of non-passive systems.The linear space of quasi-Herglotz functions constitutes a natural extension of the convex cone of Herglotz functions. It consists of differences of Herglotz functions, and we show that several of the important properties and modeling perspectives of Herglotz functions are inherited by the new set of quasi-Herglotz functions.In particular, this applies to their integral representations, the associated integral identities or sum rules (with adequate additional assumptions), their boundary values on the real axis and the associated approximation theory.Numerical examples are included to demonstrate the modeling of a non-passive gain media formulated as a convex optimization problem,where the generating measure is modeled by using a finite expansion of B-splines and point masses.
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| 10. |
- Lundgren, Malin, 1979, et al.
(författare)
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A CPHD filter for tracking with spawning models - including a FISST based derivation
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In some applications of multi-target tracking, appearing targets are suitably modeled as spawning from existing targets. However, in the original formulation of the cardinalized probability hypothesis density (CPHD) filter, this type of model is not supported; instead appearing targets are modeled by spontaneous birth only.In this paper we derive the necessary equations for a CPHD filter for the case when the process model also includes target spawning. For this generalized filter, the cardinality prediction formula might become computationally intractable for general spawning models. However, when the cardinality distribution of the spawning targets is either Bernoulli or Poisson, we derive expressions that are practical and computationally efficient. Simulations show that the proposed filter responds faster to a change in target number due to spawned targets than the original CPHD filter. In addition, the performance of the filter, considering the optimal subpattern assignment (OSPA), is improved when having an explicit spawning model.
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