Mid Sweden University

Research has identified several aspects that influence students’ transitionto mathematics studies at university, but these aspects haveoften been studied separately. Our study contributes to the field’sunderstanding of the transition between upper secondary and universitymathematics by taking a multifaceted perspective not previouslyexplored. We analyse experiences and attainment in mathematicsof 154 engineering students with respect to known aspectsof this transition, and our results show that it is important to considerseveral aspects together in order to understand the full complexity ofthe transition. It is revealed that students with previous experiencesof university studies, when compared with new first year undergraduates,perceive a larger difference between studying mathematics atthe upper secondary level and university. Our results also show thatthe engineering students enrolled in distance programmes experiencelarger differences between secondary and tertiary levels thanengineering students enrolled in campus programmes. Furthermore,our analyses show that students’ success in mathematics is relatedto their perceptions of the rift experienced in the transition. In all,our results highlight the importance of taking a student perspectivein the development of explanatory and useful models of students’transition between upper secondary and university mathematics.

In this paper we prove a general homogenization result for monotone parabolic problems with an arbitrary number of microscopic scales in space as well as in time, where the scale functions are not necessarily powers of epsilon. The main tools for the homogenization procedure are multiscale convergence and very weak multiscale convergence, both adapted to evolution problems. At the end of the paper an example is given to concretize the use of the main result.

Utmaningarna för lärare i högre utbildning att fullgöra sitt pedagogiska uppdrag har uppmärksammats och debatterats i olika sammanhang den senaste tiden (e.g. SvD, 2018-01-21; DN, 2017-09-27). Enligt Högskoleverket (2009) har skillnaderna i förkunskaper bland studenter ökat och studentgrupperna blivit större. Brommesson et al. (2016) menar att den förändrade studentpopulationen innebär en utmaning för den enskilde läraren i konkreta undervisningssituationer. Därtill förändras samhällets kompetensbehov över tid och teknisk utveckling ger möjligheter att bedriva undervisning under andra former än tidigare. Kurser och utbildningar behöver därför utvecklas över tid, för att fortsätta vara aktuella och anpassade efter de behov och förutsättningar som finns. Vid utveckling av kurser och utbildningar krävs både pedagogiska idéer och en fungerande struktur som gör denna utveckling möjlig, där idéerna tas tillvara för att senare omsättas i praktiken. Det har vid ett pedagogiskt utvecklingsprojekt vid mittuniversitetet uppmärksammats några problem med nuvarande stöd:  Resurser och information finns inte på ett ställe  Kunskapsutbyte är begränsat  Det finns inget systematiskt stöd Syfte med detta bidrag är att presentera, diskutera, och få feedback på, en modell för systematisk kursutveckling över tid, för att bemöta ovanstående problem. En modell för ständiga förbättringar presenteras, där pedagogisk utveckling och kursadministration samverkar för att på ett systematiskt sätt tillvarata idéer och lärdomar, och underlätta kunskapsutbyte. Visuellt består modellen av ett administrativt och ett pedagogiskt kurshjul som tillsammans ska täcka upp allt som behövs för att planera, genomföra och utveckla en kurs - från deadlines för administrativa moment till idéer om undervisningsformer och utvärdering. Idén är att man enkelt ska kunna klicka sig fram på en webbsida, till allt som är aktuellt/intressant i det stadie kursen befinner sig - planering, genomförande eller utvärdering och utveckling. Vi kommer att argumentera för att en fungerande kursutveckling underlättas av visuellt stöd och en tydlig arbetsgång. Målgrupp för den här presentationen är i huvudsak undervisande lärare som vill hitta vägar för att mer systematiskt arbeta med kursutveckling.

We study the homogenization of a hyperbolic-parabolic PDE with oscillations in one fast spatial scale. Moreover, the first order time derivative has a degenerate coefficient passing to infinity when ϵ→0. We obtain a local problem which is of elliptic type, while the homogenized problem is also in some sense an elliptic problem but with the limit for ϵ-1∂tuϵ as an undetermined extra source term in the right-hand side. The results are somewhat surprising and work remains to obtain a fully rigorous treatment. Hence the last section is devoted to a discussion of the reasonability of our conjecture including numerical experiments.

We study the homogenization of a certain linear hyperbolic-parabolic problem exhibiting two rapid spatial scales {ε; ε²}. The homogenization is performed by means of evolution multiscale convergence, a generalization of the concept of two-scale convergence to include any number of scales in both space and time. In particular we apply a compactness result for gradients. The outcome of the homogenization procedure is that we obtain a homogenized problem of hyperbolic-parabolic type together with two elliptic local problems, one for each rapid scale, for the correctors.

This paper concerns the homogenization of nonlinear dissipative hyperbolic problems partial derivative ttu(epsilon) (x, t) - del . (a(x/epsilon(q1),..., x/epsilon(qn), t/epsilon(r1),..., t/epsilon(rm)) del u(epsilon) (x, t)) +g (x/epsilon(r1),..., x/epsilon(rn), t/epsilon(r1), u(epsilon) (x, t), del u(epsilon) (x, t)) = f (x, t)

where both the elliptic coefficient a and the dissipative term a are periodic in the n + m first arguments where n and m may attain any non-negative integer value. The homogenization procedure is performed within the framework of evolution multiscale convergence which is a generalization of two-scale convergence to include several spatial and temporal scales. In order to derive the local problems, one for each spatial scale, the crucial concept of very weak evolution multiscale convergence is utilized since it allows less benign sequences to attain a limit. It turns out that the local problems do not involve the dissipative term g even though the homogenized problem does and, due to the nonlinearity property, an important part of the work is to determine the effective dissipative term. A brief illustration of how to use the main homogenization result is provided by applying it to an example problem exhibiting six spatial and eight temporal scales in such a way that a and g have disparate oscillation patterns.

The main contribution of this paper is the homogenization of the linearparabolic equationtu (x, t) − ·axq1, ...,xqn,tr1, ...,trmu (x, t)= f(x, t)exhibiting an arbitrary finite number of both spatial and temporal scales.We briefly recall some fundamentals of multiscale convergence and providea characterization of multiscale limits for gradients in an evolution settingadapted to a quite general class of well-separated scales, which we nameby jointly well-separated scales (see Appendix for the proof). We proceedwith a weaker version of this concept called very weak multiscale convergence.We prove a compactness result with respect to this latter typefor jointly well-separated scales. This is a key result for performing thehomogenization of parabolic problems combining rapid spatial and temporaloscillations such as the problem above. Applying this compactnessresult together with a characterization of multiscale limits of sequences ofgradients we carry out the homogenization procedure, where we togetherwith the homogenized problem obtain n local problems, i.e. one for eachspatial microscale. To illustrate the use of the obtained result we apply itto a case with three spatial and three temporal scales with q1 = 1, q2 = 2and 0 < r1 < r2.MSC: 35B27; 35K10

We consider the homogenization of the linear parabolic problem rho(x/epsilon(2))partial derivative(t)u(epsilon)(x,t) - del . (a(x/epsilon(1), t/epsilon(2)(1))del u(epsilon) (x,t)) = f(x,t) which exhibits a mismatch between the spatial scales in the sense that the coefficient a(x/epsilon(1), t/epsilon(2)(1)) of the elliptic part has one frequency of fast spatial oscillations, whereas the coefficient rho(x/epsilon(2)) of the time derivative contains a faster spatial scale. It is shown that the faster spatialmicroscale does not give rise to any corrector termand that there is only one local problemneeded to characterize the homogenized problem. Hence, the problem is not of a reiterated type even though two rapid scales of spatial oscillation appear.

We first study the fundamental ideas behind two-scale conver-

gence to enhance an intuitive understanding of this notion. The classical

definitions and ideas are motivated with geometrical arguments illustrated

by illuminating figures. Then a version of this concept, very weak two-scale

convergence, is discussed both independently and brie°y in the context of

homogenization. The main features of this variant are that it works also

for certain sequences of functions which are not bounded in

L2  and at

the same time is suited to detect rapid oscillations in some sequences which

are strongly convergent in

L2 . In particular, we show how very weak

two-scale convergence explains in a more transparent way how the oscilla-

tions of the governing coe±cient of the PDE to be homogenized causes the

deviation of the

G-limit from the weak L2 NxN-limit for the sequence of

coe±cients. Finally, we investigate very weak multiscale convergence and

prove a compactness result for separated scales which extends a previous

result which required well-separated scales.