| 1. |
- Gerlee, Philip, 1980, et al.
(författare)
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Scientific Models : Red Atoms, White Lies and Black Boxes in a Yellow Book
- 2016
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- A zebrafish, the hull of a miniature ship, a mathematical equation and a food chain - what do these things have in common? They are examples of models used by scientists to isolate and study particular aspects of the world around us. This book begins by introducing the concept of a scientific model from an intuitive perspective, drawing parallels to mental models and artistic representations. It then recounts the history of modelling from the 16th century up until the present day. The iterative process of model building is described and discussed in the context of complex models with high predictive accuracy versus simpler models that provide more of a conceptual understanding. To illustrate the diversity of opinions within the scientific community, we also present the results of an interview study, in which ten scientists from different disciplines describe their views on modelling and how models feature in their work. Lastly, it includes a number of worked examples that span different modelling approaches and techniques. It provides a comprehensive introduction to scientific models and shows how models are constructed and used in modern science. It also addresses the approach to, and the culture surrounding modelling in different scientific disciplines. It serves as an inspiration for model building and also facilitates interdisciplinary collaborations by showing how models are used in different scientific fields. The book is aimed primarily at students in the sciences and engineering, as well as students at teacher training colleges but will also appeal to interested readers wanting to get an overview of scientific modelling in general and different modelling approaches in particular.
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| 2. |
- Gerlee, Philip, 1980, et al.
(författare)
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Scientific Models
- 2016
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- A zebrafish, the hull of a miniature ship, a mathematical equation and a food chain - what do these things have in common? They are examples of models used by scientists to isolate and study particular aspects of the world around us. This book begins by introducing the concept of a scientific model from an intuitive perspective, drawing parallels to mental models and artistic representations. It then recounts the history of modelling from the 16th century up until the present day. The iterative process of model building is described and discussed in the context of complex models with high predictive accuracy versus simpler models that provide more of a conceptual understanding. To illustrate the diversity of opinions within the scientific community, we also present the results of an interview study, in which ten scientists from different disciplines describe their views on modelling and how models feature in their work. Lastly, it includes a number of worked examples that span different modelling approaches and techniques. It provides a comprehensive introduction to scientific models and shows how models are constructed and used in modern science. It also addresses the approach to, and the culture surrounding modelling in different scientific disciplines. It serves as an inspiration for model building and also facilitates interdisciplinary collaborations by showing how models are used in different scientific fields. The book is aimed primarily at students in the sciences and engineering, as well as students at teacher training colleges but will also appeal to interested readers wanting to get an overview of scientific modelling in general and different modelling approaches in particular.
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| 3. |
- Andreasson, Håkan, 1966, et al.
(författare)
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Comments on the paper ‘Static solutions of the Vlasov–Einstein system’ by G. Wolansky
- 2020
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Ingår i: Archive for Rational Mechanics and Analysis. - : Springer Science and Business Media LLC. - 1432-0673 .- 0003-9527. ; 235:1, s. 783-791
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Tidskriftsartikel (refereegranskat)abstract
- In this note we address the attempted proof of the existence of static solutions to the Einstein–Vlasov system as given in Wolansky (Arch Ration Mech Anal 156:205–230, 2001). We focus on a specific and central part of the proof which concerns a variational problem with an obstacle. We show that two important claims in Wolansky (2001) are incorrect and we question the validity of a third claim. We also discuss the variational problem and its difficulties with the aim of stimulating further investigation of this intriguing problem in particular answering the question of whether or not static solutions of the Einstein–Vlasov system can be found as local minimizers of an energy-Casimir functional.
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| 4. |
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| 5. |
- Johansson, Christian, 1985, et al.
(författare)
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Endoscopy on SL2-eigenvarieties
- 2024
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Ingår i: Journal fur die Reine und Angewandte Mathematik. - 1435-5345 .- 0075-4102. ; 2024:813, s. 1-79
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we study p -adic endoscopy on eigenvarieties for <> SL 2 \mathrm{SL}_{2} over totally real fields, taking a geometric perspective. We show that non-automorphic members of endoscopic L -packets of regular weight contribute eigenvectors to overconvergent cohomology at critically refined endoscopic points on the eigenvariety, and we precisely quantify this contribution. This gives a new perspective on and generalizes previous work of the second author. Our methods are geometric, and are based on showing that the <> SL 2 \mathrm{SL}_{2} -eigenvariety is locally a quotient of an eigenvariety for <> GL 2 \mathrm{GL}_{2}, which allows us to explicitly describe the local geometry of the <> SL 2 \mathrm{SL}_{2} -eigenvariety. In particular, we show that it often fails to be Gorenstein.
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| 6. |
- Jonsson, Adam, et al.
(författare)
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Consequentialism in infinite worlds
- 2020
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Ingår i: Analysis. - : Oxford University Press. - 0003-2638 .- 1467-8284. ; 80:2, s. 240-248
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Tidskriftsartikel (refereegranskat)abstract
- We show that in infinite worlds, the following three conditions are incompatible: 1) The spatiotemporal ordering of individuals is morally irrelevant. 2) All else being equal, the act of bringing about a good outcome with a high probability is better than the act of bringing about the same outcome with a low probability. 3) One act is better than another only if there is a nonzero probability that it brings about a better outcome. The impossibility of combining these conditions shows that it is more costly to endorse 1) than has been previously acknowledged.
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| 7. |
- Romano, Luigi, 1994
(författare)
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Steady-State Brush Theory
- 2022
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Ingår i: SpringerBriefs in Applied Sciences and Technology. - Cham : Springer International Publishing. - 2191-530X .- 2191-5318. ; , s. 35-55
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In steady-state conditions, explicit expressions for tyre characteristics may be derived using the theoretical framework provided by the brush theory. This chapter is, thus, dedicated to addressing the stationary problem from both the local and global perspectives. The fundamental concepts of critical slip and spin are introduced with respect to an isotropic tyre, and the deformation of the bristles inside the contact patch is investigated for different operating conditions of the tyre. Analytical functions describing the tyre forces and moment acting inside the contact patch are obtained for the particular case of a rectangular contact patch. The analysis is qualitative in nature.
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| 8. |
- Hezari, H., et al.
(författare)
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The Dirichlet isospectral problem for trapezoids
- 2021
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Ingår i: Journal of Mathematical Physics. - : AIP Publishing. - 0022-2488 .- 1089-7658. ; 62:5
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Tidskriftsartikel (refereegranskat)abstract
- We show that non-obtuse trapezoids are uniquely determined by their Dirichlet Laplace spectrum. This extends our previous result [Hezari et al., Ann. Henri Poincare 18(12), 3759-3792 (2017)], which was only concerned with the Neumann Laplace spectrum.
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| 9. |
- Maligranda, Lech, 1953-
(författare)
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„B” jak przestrzeń Banacha : [“B” as Banach space]
- 2020
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Ingår i: Wiadomosci Matematyczne. - Warszawa : Polskie Towarzystwo Matematyczne. - 2080-5519. ; 56:1, s. 15-27
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Tidskriftsartikel (refereegranskat)abstract
- W związku ze stuleciem pracy doktorskiej Stefana Banacha, przyjętej do oceny 24 czerwca 1920 roku na Uniwersytecie Jana Kazimierza we Lwowie i opublikowanej w 1922 roku w Fundamenta Mathematicae, w artykule omówiona zostanie sprawa wprowadzenia nazwy ,,B-przestrzeń" i ,,przestrzeń Banacha". Niniejszy artykuł został podzielony na cztery części: klasyczne przestrzenie unormowane i przestrzenie metryczne przed 1920 rokiem, przestrzenie liniowe unormowane i zupełne, B-przestrzenie i przestrzenie Banacha, a na koniec wspomine są także przestrzenie quasi-Banacha.
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| 10. |
- Sehlström, Alexander, 1987
(författare)
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Prestress in Nature and Technics
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To direct the forces of nature is a central task in the creation of spaces and load-carrying structures for architecture. This research investigates how prestress can be used as a design tool for the creation of material efficient and well-functioning structures, and in early design stages contribute to sustainable, functional and beautiful architecture. The thesis begins with a discussion about central concepts such as stress and stiffness. Stiffness can be understood as the sum of elastic stiffness and geometric stiffness and the latter is differently influenced by the presence of tensile or compressive stresses. Only structures that are statically indeterminate are possible to prestress so that the stress pattern is affected. The terms externally-equilibrated and auto-equilibrated prestressed structures are introduced. The design of load-bearing structures for architecture requires a collaboration between architects and engineers and the conditions for a successful collaboration is reflected upon. Prominent design cultures are highlighted and the one this research is linked to is described. A collection of historic and contemporary examples of prestressed structures is presented. The focus is architectural applications but examples from other realms are also included. From this collection, a framework for prestressed structures is proposed and discussed which considers five perspectives. The first explores the historical knowledge development. The second is devoted to structural mechanical modes of actions where material behaviour, member actions and structural systems are discussed. The third highlights computational strategies and those appropriate for early stage design are distinguished from those suitable for late stage verification. The fourth perspective seeks to establish objectives for why prestress is used. The fifth perspective leads to suggestions for strategies for how the prestress is achieved. Three papers are included. Paper A presents a numerical method for the form finding of prestressed gridshells consisting of both compressed and tensioned members. Paper B describes a structural design process where methods usually applied by architects are used by structural engineers. The work resulted in the construction of a temporary pavilion consisting of a post-tensioned wooden gridshell called the Wood Fusion Pavilion. Paper C explores under what conditions an unloaded shell formed of a closed surface unattached to any supports can contain a state of membrane stress which can be induced by prestressing. It is concluded that a torus can be prestressed, but there must almost certainly be more to explore.
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