| 1. |
- Eriksson, Anders, 1972, et al.
(författare)
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Rotation Averaging and Strong Duality
- 2018
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Ingår i: Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition. - 1063-6919. - 9781538664209 ; , s. 127-135
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Konferensbidrag (refereegranskat)abstract
- In this paper we explore the role of duality principles within the problem of rotation averaging, a fundamental task in a wide range of computer vision applications. In its conventional form, rotation averaging is stated as a minimization over multiple rotation constraints. As these constraints are non-convex, this problem is generally considered challenging to solve globally. We show how to circumvent this difficulty through the use of Lagrangian duality. While such an approach is well-known it is normally not guaranteed to provide a tight relaxation. Based on spectral graph theory, we analytically prove that in many cases there is no duality gap unless the noise levels are severe. This allows us to obtain certifiably global solutions to a class of important non-convex problems in polynomial time. We also propose an efficient, scalable algorithm that out-performs general purpose numerical solvers and is able to handle the large problem instances commonly occurring in structure from motion settings. The potential of this proposed method is demonstrated on a number of different problems, consisting of both synthetic and real-world data.
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| 2. |
- Adman, Per, et al.
(författare)
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171 forskare: ”Vi vuxna bör också klimatprotestera”
- 2019
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Ingår i: Dagens nyheter (DN debatt). - Stockholm. - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 26/9. Vuxna bör följa uppmaningen från ungdomarna i Fridays for future-rörelsen och protestera eftersom det politiska ledarskapet är otillräckligt. Omfattande och långvariga påtryckningar från hela samhället behövs för att få de politiskt ansvariga att utöva det ledarskap som klimatkrisen kräver, skriver 171 forskare i samhällsvetenskap och humaniora.
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| 3. |
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| 4. |
- Eriksson, Olivia, PhD, 1971-, et al.
(författare)
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e-Science in Scandinavia
- 2018
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Ingår i: Informatik-Spektrum. - : Springer Science and Business Media LLC. - 0170-6012 .- 1432-122X. ; 41:6, s. 398-404
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Gunell, Herbert, et al.
(författare)
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Plasma waves confined to the diamagnetic cavity of comet 67P/Churyumov-Gerasimenko
- 2017
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 469, s. S84-S92
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Tidskriftsartikel (refereegranskat)abstract
- Ion acoustic waves were observed in the diamagnetic cavity of comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft on 2015 August 3, when the comet was 1.25 au from the Sun. Wave spectra recorded by the Langmuir probe (RPC-LAP), peak near 200 Hz, decrease for higher frequencies and reach the noise floor at approximately 1.5 kHz. These waves were observed only when the spacecraft was in the diamagnetic cavity or at its boundary, which is identified as a sharp drop in magnetic field magnitude, measured by RPC-MAG. The plasma, on both sides of the boundary, is dominated by a cold (a few hundred K) water group ion population, one cold (k(B)T(e) similar to 0.1 eV) and one warm (k(B)T(e) similar to 10 eV) electron population. The observations are interpreted in terms of current-driven ion acoustic waves, generated by currents that flow through bulges on the boundary of the diamagnetic cavity.
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| 6. |
- Högdin, Sara, 1972-, et al.
(författare)
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Strategies to strengthen outlook of life among young people : A case study in a Swedish municipality
- 2016
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Ingår i: SWSD 2016.
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Konferensbidrag (refereegranskat)abstract
- There is a continuous increase in mental health problems, such as stress symptoms, among young people in the Nordic countries. One source of stress concerns young people’s outlook of life in general, and more specific the choice of education and future carrier. Previous studies show that high education has positive impact on a person’s health, but also on regional development. The research project is based on a case study in a Swedish municipality with low educational level. The aim of the study is to explore and understand the low education among the citizens. The study starts in young person’s perspective on their future. Further, how adults in home, school and the neighborhood, influence the young person’s educational and carrier choices. The analyses of the results are based on theories on gender and cultural/social capital. The empirical material consists of surveys and interview studies with young people, teachers and guidance counsellors. The results show that young people often feel unsure of their future chooses and often ask for more support from adults regarding their future education. Several students find it stressful to manage their career choices, particularly if their parents do not have sufficient knowledge to support them in such matters. Teachers and guidance counselors describe a lack of strategies to support and addressing issues of education and future work, but also how they should be passive in relation to influencing the students. In conclusion, the results show the importance, when it comes to social work and social development practices on preventing mental health problems among young people, to develop strategies for working with young person’s educational and carrier choices. In this project some strategies have been identified, on local political and school level, to strengthen outlook of life among young people.
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| 7. |
- Högdin, Sara, 1972-, et al.
(författare)
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Young people's educational and career choices : A case study among young people, guidance counsellors and teachers in a Swedish municipality
- 2016
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Ingår i: NERA2016. ; , s. 89-89
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Konferensbidrag (refereegranskat)abstract
- In a changing and complex world, young people are expected to make decisions and choices regarding their education and future careers. At the same time, there is a continuous increase in mental health problems, such as stress symptoms, among young people in the Nordic countries. One source of stress concerns young people’s outlook on life in general, and more specifically their choice of education and career. This paper is based on a research project in a Swedish municipality with a low level of education. The overall aim of the project was to explore and understand the low education among the citizens in the municipality. The aim of this paper is to illustrate how career counsellors and teachers view their role in supporting students when it comes to these choices, and how young people view the support they receive and have received during their years at compulsory and upper secondary school. The empirical material consists of surveys and interview studies with young people, teachers and career counsellors. The analyses of the results are based on Pierre Bourdieu’s theory of field, capital and habitus with a gender perspective from Beverley Skeggs’ theory on gender and capital. The study takes young people’s perspectives of their education and careers as its starting point. It also examines the support they have received from career counsellors and teachers at compulsory and upper secondary school and also from their parents and other significant persons in their home environment. The analyses show that there are differences in how professionals and young people view study and career guidance. Young people often express a feeling of uncertainty when it comes to their future choices and request more guidance from adults regarding possible opportunities. Several students find it stressful to manage their career choices, particularly if their parents do not have sufficient knowledge to support them in such matters. Girls express a feeling of stress in relation to educational choices more often than boys. Teachers and career counsellors describe a lack of strategies when it comes to vocational guidance and how to address issues of education and future work within the current curriculum. They also express a fear of influencing young people and therefore take a more passive approach in these matters. In conclusion, the results show that there is a gap between young people’s requests for guidance from adults at school and teachers’ and career counsellors’ view of their role in these matters. The results highlights the importance of developing strategies for working with educational and career choices at compulsory school as one way of preventing mental health problems among young people.
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| 8. |
- Johannesson, Tomas, 1975-
(musiker, creator_code:sds_t, creator_code:cre_t)
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Norrbotten blues : CD-produktion av Ronny Eriksson och Ramblin' Minds
- 2019
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Konstnärligt arbeteabstract
- CD-inspelning: Norrbotten blues - Ronny Eriksson & Ramblin' MindsLåtlista1. Norrbotten Blues2. Gråtvals3. På kanten av en grop4. Flyktingarna5. Då tänker jag på Syrien6. Låt mig gå, jag har inte tid att stanna7. Tröstvals8. Blues för ingen alls9. Brorsan10. Den officiella versionen11. Blues under fullmånenMusikerRonny Eriksson - sångMikael Bäckman - munspelLeo Holmberg - gitarr/körAnders Wedin - gitarrAnna Wedin - bas/körKatarina Pettersson - trummorMathias Lundqvist - piano/orgelTomas Johannesson - barytonsaxStefan Tjerngren - tenorsaxTomas Johannesson - Ljudtekniker (inspelning, redigering och mix)Stockholm Mastering - masteringRootsy Music - bolagInspelat på musikhögskolan i Piteå 7-9 september 2018.Publicerad 9 mars 2019.
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| 9. |
- Mao, Huina
(författare)
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Numerical and Experimental Studies of Deployment Dynamics of Space Webs and CubeSat Booms
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, experiments and simulations are performed to study the deployment dynamics of space webs and space booms, focusing on the deployment and stabilization phases of the space web and the behavior of the bi-stable tape spring booms after long-term stowage.The space web, Suaineadh, was launched onboard the sounding rocket REXUS-12 from the Swedish launch base Esrange in Kiruna on 19 March 2012. It served as a technology demonstrator for a space web. A reaction wheel was used to actively control the deployment and stabilization states of the 2×2 m2 space web. After ejection from the rocket, the web was deployed but entanglements occurred since the web did not start to deploy at the specified angular velocity. The deployment dynamics was reconstructed by simulations from the information recorded by inertial measurement units and cameras. Simulations show that if the web would have started to deploy at the specified angular velocity, the web would most likely have been deployed and stabilized in space by the motor, reaction wheel and controller used in the experiment. A modified control method was developed to stabilize the out-of-plane motions before or during deployment. New web arms with tape springs were proposed to avoid entanglements.A deployable booms assembly composed of four 1-m long bi-stable glass fiber tape springs was designed for the electromagnetically clean 3U CubeSat Small Explorer for Advanced Missions (SEAM). The deployment dynamics and reliability of the SEAM boom design after long-term stowage were tested by on-ground experiments. A simple analytical model was developed to predict the deployment dynamics and to assess the effects of the GOLS and the combined effects of friction, viscoelastic strain energy relaxation, and other factors that act to decrease the deployment force. In order to mitigate the viscoelastic effects and thus ensure self-deployment, different tape springs were designed, manufactured and tested. A numerical model was used to assess the long-term stowage effects on the deployment capability of bi-stable tape springs including the friction, nonlinear-elastic and viscoelastic effects. A finite element method was used to model a meter-class fully coiled bi-stable tape spring boom and verified by analytical models.
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| 10. |
- Nåbo, Arne, 1958-, et al.
(författare)
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Elvägar i körsimulator : design, test, utvärdering och demonstration av elvägstekniker och elfordon med virtuella metoder
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Elvägar, där el överförs kontinuerligt till fordon på vägen, kan vara ett sätt att nå målet om en fossiloberoende transportsektor. För att testa och utvärdera elvägar och elfordon på elvägar i ett tidigt stadium utvecklades en demonstrationsmiljö i körsimulator. En studie genomfördes med 25 förare där varje förare fick köra en 40 kilometer lång vägsträcka, dels med en hybridlastbil på elväg, dels med en konventionell lastbil utan elväg. Körning på elväg uppvisade inga anmärkningsvärda skillnader på förarens upplevelser vad gäller säkerhet och estetik eller körbeteende jämfört med körning utan elväg. Undantaget var medelhastigheten vilken var cirka 2 kilometer/timme högre på elväg. Energianvändningen var cirka 35 procent lägre på elväg. För att sprida projektresultatet till aktörer och intressenter av elvägar har ett stort antal demonstrationer genomförts, samt kommunikation via pressreleaser och tidningsartiklar. Det har även tagits fram en mindre, mobil körsimulator för elvägar som ett led i att nå ut till en större målgrupp.
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