445 research outputs found
Picard - an electrostatic particle in cell simulation code
No full textThis is a particle-in-cell plasma code 'picard' that was developed
by Jesper Lindkvist and Herbert Gunell with start in 2016 using
resources provided by the Swedish National Infrastructure for
Computing (SNIC) at the High Performance Computing Center North
(HPC2N), Umeå University, Sweden. Jesper Lindkvist was funded by
the Swedish National Space Board (SNSB project 201/15) and
Herbert Gunell by the Swedish National Space Agency (SNSA
project 108/18).
A paper based on the first version was published in A&A .
The present version has been updated to include ionisation as a source of cometary ions, and hdf5 files are used for writing the output. The changes in this version were made by Herbert Gunell.
The files included are:
picard.tgz Package containing all source file, some matlab m-files
that can be used for plotting of the results, and an input
file that was used for a simulation that will be used in an
upcoming publication by Herbert Gunell and Charlotte Götz.
fig-cur.mp4 Videoclip showing results from the simulation defined by the input file, specifically
three-dimensional current paths from different angles.
@author : Jesper Lindkvist
Email : [email protected]
@author : Herbert Gunell
Email : [email protected]
Hur reagerar svenska hushålls sparkvot på förändringar i real styrränta? : En dynamisk tidsserieanalys i Sverige 1996–2024
No full textType Theory Unchained: Extending Agda with User-Defined Rewrite Rules
No full textDependently typed languages such as Coq and Agda can statically guarantee the correctness of our proofs and programs. To provide this guarantee, they restrict users to certain schemes a- such as strictly positive datatypes, complete case analysis, and well-founded induction a- that are known to be safe. However, these restrictions can be too strict, making programs and proofs harder to write than necessary. On a higher level, they also prevent us from imagining the different ways the language could be extended. In this paper I show how to extend a dependently typed language with user-defined higher-order non-linear rewrite rules. Rewrite rules are a form of equality reflection that is applied automatically by the typechecker. I have implemented rewrite rules as an extension to Agda, and I give six examples how to use them both to make proofs easier and to experiment with extensions of type theory. I also show how to make rewrite rules interact well with other features of Agda such as-equality, implicit arguments, data and record types, irrelevance, and universe level polymorphism. Thus rewrite rules break the chains on computation and put its power back into the hands of its rightful owner: Yours.Programming Language
35 frågor och svar inför en edering av Jesper Swedbergs Swensk Ordabok
No full textIn this paper, the author accounts for his work on editing an early 18th centurydictionary manuscript, bishop Jesper Swedberg’s Swensk Ordabok. A similar project– i.e. editing an old, hitherto unpublished dictionary manuscript – has beenperformed in Sweden only once before. This means that there is no tradition onwhich the solution of many problems concerning the edition of Swedberg'sdictionary could be based. For instance, there are no less than five manuscriptversions. Which of them should be selected as the basis manuscript of the edition,and to what extent should the differences between the manuscripts be accounted forin the edition? As argued by the author, none of the manuscripts written bySwedberg himself can serve as the basis manuscript, since they are all incomplete.Also, a relatively restricted account of the differences between the manuscripts issuggested; otherwise, the readability of the edition would be too low
Exploration and reflection in interactive art: Glass pond
No full textGlass Pond is an interactive artwork designed to engender exploration and reflection through an intuitive, tangible interface and a simulation agent. It is being developed using iterative methods. A study has been conducted with the aim of illuminating user experience, interface, design, and performance issues.The paper describes the study methodology and process of data analysis including coding schemes for cognitive states and movements. Analysis reveals that exploration and reflection occurred as well as composing behaviours (unexpected). Results also show that participants interacted to varying degrees. Design discussion includes the artwork's (novel) interface and configuration. Copyright the author(s) and CHISIG
Real Estate Agent as a profession : A study regarding the occupation´s professional categorization
No full textTitel: Fastighetsmäklare som profession - En studie om yrkets professionskategorisering Nivå: Kandidatuppsats i ämnet Fastighetsvetenskap Författare: Jesper Arnshed Handledare: Karin Staffansson Pauli Datum: Maj 2021 Syfte: Med utgångspunkt i de fördelar som tillkommer av att nå en högre profession, är syftet med denna studie att undersöka fastighetsmäklarbranschens syn på kategoriseringen av mäklarprofessionen Metod: Denna studie har applicerat en kvalitativ forskningsmetodik. Med hjälp av semistrukturerade intervjuer har empirisk data kopplats till den teoretiska bakgrunden, om de bakomliggande aspekterna som bidrar till fastighetsmäklarens professionskategorisering. Resultat & Slutsats: Resultatet visar att mäklarens strävan mot högre profession delvis försvåras till följd av glappet mellan teori och praktik, samt de odefinierade regel- och ramverk som mäklare har att förhålla sig till. Om den nya lagändringen istället hade varit förankrad i de reella utmaningar och faktorer som påverkar förtroendet och yrkesintegriteten för mäklaren, finns där stora möjligheter för yrkesgruppen att nå en högre profession. Uppsatsens bidrag till ämnet: Studien har bidragit med ytterligare förståelse för mäklarens profession och vad som förhindrar en högre kategorisering. Förslag till framtida forskning: Efterhand som lagändringen har blivit implementerad vore det intressant att studera vilka förändringar som fått genomslag i branschen och för mäklaren.Title: Real Estate Agent as a profession - A study about the occupation´s professional categorization Level: Bachelor's thesis within Real Estate Science Author: Jesper Arnshed Supervisor: Karin Staffansson Pauli Date: May 2021 Aim: Based on the benefits of reaching a higher profession, the aim of this study is to examine the real estate industry's view on the categorization of the broker´s profession. Method: This study has applied a qualitative research methodology. With the help of semi-structured interviews, additional dimensions have supplemented the theoretical background, about the underlying aspects that are derived from the real estate agent's professional classification. Result & Conclusions: The result shows that the brokers´ aim towards a higher profession is partly prevented due to the gap between theory and practice, and the undefined rules and regulations that brokers must deal with. If the new law change had instead been rooted in the real challenges and aspects that affect the trust and professional integrity among brokers, there are great opportunities for the occupational group to reach a higher profession. Contribution of the thesis: The study contributed with additional understanding to the broker´s profession and what prevents a higher categorization. Suggestions for future research: As the changes in the law are implemented, it would be interesting to study what changes have had an impact in the industry and for the broker.
Dependently Typed Languages in Statix
No full textStatic type systems can greatly enhance the quality of programs, but implementing a type checker that is both expressive and user-friendly is challenging and error-prone. The Statix meta-language (part of the Spoofax language workbench) aims to make this task easier by automatically deriving a type checker from a declarative specification of a type system. However, so far Statix has not been used to implement dependent types, which is a class of type systems which require evaluation of terms during type checking. In this paper, we present an implementation of a simple dependently typed language in Statix, and discuss how to extend it with several common features such as inductive data types, universes, and inference of implicit arguments. While we encountered some challenges in the implementation, our conclusion is that Statix is already usable as a tool for implementing dependent types
Experts Roundtable:Exploring Climate Change, Human Rights & Forced Displacement
No full textHosted by: Law Dept, Aalborg University (AAU) & Global Refugee Studies, Dep. of Culture and Global Studies, AAU Chair: Ass. Prof. Sandra Cassotta (Associate Professor, IEEL, Aalborg Univ /Adj Prof., Western Sydney Univ, Lead Author at the IPCC – International Panel of Climate Change), Co-chair: Ass. Prof. Jesper Lindholm (Associate Professor, Public International Law, Human Rights & Asylum, Aalborg Univ) Speakers: Lecturer Annalisa Savaresi (Lecturer in Environmental Law, Co-Director, LLM/MSc Environmental Policy & Governance, Stirling University); Assist.Prof Martin Lemberg-Pedersen (Assist. Professor, Global Refugee Studies, AAU) & Ms. Melina Riemer (Researcher, University of Münste
A comparative study of first and all-author co-citation counting, and two different matrix generation approaches applied for author co-citation analyses
No full textAim: The present article contributes to the current methodological debate concerning author co-citation analyses. (ACA) The study compares two different units of analyses, i.e. first- versus inclusive all-author co-citation counting, as well as two different matrix generation approaches, i.e. a conventional multivariate and the so-called Drexel approach, in order to investigate their influence upon mapping results. The aim of the present study is therefore to provide more methodological awareness and empirical evidence concerning author co-citation studies. Method: The study is based on structured XML documents extracted from the IEEE collection. These data allow the construction of ad-hoc citation indexes, which enables us to carry out the hitherto largest all-author co-citation study. Four ACA are made, combining the different units of analyses with the different matrix generation approaches. The results are evaluated quantitatively by means of multidimensional scaling, factor analysis, Procrustes and Mantel statistics. Results: The results show that the inclusion of all cited authors can provide a better fit of data in two-dimensional mappings based on MDS, and that inclusive all-author co-citation counting may lead to stronger groupings in the maps. Further, the two matrix generation approaches produce maps that have some resemblances, but also many differences at the more detailed levels. The Drexel approach produces results that have noticeably lower stress values and are more concentrated into groupings. Finally, the study also demonstrates the importance of sparse matrices and their potential problems in connection with factor analysis. Conclusion: We can confirm that inclusive all-ACA produce more coherent groupings of authors, whereas the present study cannot clearly confirm previous findings that first-ACA identifies more specialties, though some vague indication is given. Most crucially, strong evidence is given to the determining effect that matrix generation approaches have on the mapping of author co-citation data and thus the interpretation of such maps. Evidence is provided for the seemingly advantages of the Drexel approach
A Comparison between Different Recommender System Approaches for a Book and an Author Recommender System
No full textA recommender system is a popular tool used by companies to increase customer satisfaction and to increase revenue. Collaborative filtering and content-based filtering are the two most common approaches when implementing a recommender system, where the former provides recommendations based on user behaviour, and the latter uses the characteristics of the items that are recommended. The aim of the study was to develop and compare different recommender system approaches, for both book and author recommendations and their ability to predict user ratings of an e-book application. The evaluation of the models was done by measuring root mean square error (RMSE) and mean absolute error (MAE). Two pure models were developed, one based on collaborative filtering and one based on content-based filtering. Also, three different hybrid models using a combination of the two pure approaches were developed and compared to the pure models. The study also explored how aggregation of book data to author level could be used to implement an author recommender system. The results showed that the aggregated author data was more difficult to predict. However, it was difficult to draw any conclusions of the performance on author data due to the data aggregation. Although it was clear that it was possible to derive author recommendations based on data from books. The study also showed that the collaborative filtering model performed better than the content-based filtering model according to RMSE but not according to MAE. The lowest RMSE and MAE, however, were achieved by combining the two approaches in a hybrid model
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