| 1. |
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| 2. |
- Andersson, Björn O, 1982, et al.
(författare)
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MPI-Parallelization of a Structured Grid CFD Solver including an Integrated Octree Grid Generator
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- An existing Computational Fluid Dynamics (CFD) solver is parallelized by means of MPI. The solver includes a dynamic and adaptive grid generator for Cartesian Quadtree and Octree grids, which therefore also have to be parallelized. The grid generator generates grids fulfilling a specific set of rules, that have to be enforced also in parallel. The assembly of the large sparse matrices resulting from the implicit discretization of Navier-Stokes equations is done in parallel, as is the solving process. The parallel performance of both of these processes depends heavily on a good load balancing in order to reach satisfactory speedup. Two versions of load balancing are demonstrated, one based on block swapping, and the other by utilizing the Metis or Parmetis software packages for load balancing of graphs. Results are presented for load balancing and for the parallel speedup of solving the linear algebra system of equations.
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| 3. |
- Dahlstedt, Magnus, et al.
(författare)
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Problematizing parents : representations of multi-ethnic areas, youth and urban unrest
- 2017
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Ingår i: Reimagineering the nation. - Frankfurt am Main : Peter Lang Publishing Group. - 9783631715185 - 9783631715208 - 3631715188 ; , s. 209-233
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Bokkapitel (refereegranskat)abstract
- The causes of and solutions to juvenile delinquency and social unrest amongthe youth in so-called Swedish multi-ethnic urban areas are frequently represented inpublic-institutional discourse as related to migrant parents. These are, the authors argue,consequently exposed to policies for ‘activation’, ‘responsibilisation’ and ‘normalisation’.
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| 4. |
- Demaziere, Christophe, 1973, et al.
(författare)
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Investigation of efficient and reliable numerical algorithms for coupled reactor calculations - XTREAM project - Tasks 3a, 3b and 4a
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this report, some of the work performed in the framework of the X-TREAM project (with X-TREAM standing for neXt generation numerical Techniques for deterministic REActor Modelling) is reported. The work was supported by the Nordic Thermal Hydraulic Network (NORTHNET). The focus of the report is on the tasks 3a and 3b (elaboration of 1-D test cases and comparisons of non-linear inconsistent/consistent methods) and on the task 4a (recommendations for non-linear consistent reactor safety simulations). A simplified one-dimensional Boiling Water Reactor (BWR) model in steady-state conditions was developed to study the efficiency of the Jacobian-Free Newton Krylov (JFNK) method to solve strongly non-linear multi-physic problems, such as the one corresponding to BWR behaviour, where the interdependence between neutron transport, fluid dynamics and heat transfer needs to be resolved. The modelling assumptions were chosen so that the physics of BWRs could be properly accounted for with an as simple as possible model. It was found that there is little advantage of solving each of the mono-physics problems using a JFNK approach and iterating between the various solvers until convergence is reached. As noticed with classical operator splitting approaches, such a solver is prone to oscillatory behaviour due to the strong physical coupling between coolant density/fuel temperature and the distributions of neutrons in space/energy. Such oscillations can only be overcome by using some relaxation factor, which results in slow convergence of the overall multi-physics problem. On the other hand, it was also demonstrated that solving the entire multi-physics problem simultaneously using JFNK is a very powerful technique. The robustness of this technique nevertheless relies on two important aspects: the necessity to create a good enough initial guess to be used by the JFNK algorithm and the need to properly precondition the problem. For the former, using a non-linear Gauss-Seidel technique was proven to provide such an acceptable guess. For the latter, an efficient preconditioner was found to have the following characteristics: separate preconditioning of the neutron transport problem, no preconditioning of the heat transfer problem, preconditioning of the fluid dynamics problem where the cross-dependencies between the void fraction and the phasic velocities are resolved and where the pressure field is treated independently. Based on these characteristics, an analytical preconditioner using first-order (i.e. linear) approximations of the balance equations and relying on a simpler formulation of the problem solved was derived and demonstrated to be efficient. The development of such an analytical preconditioner, which is the key condition to be fulfilled for a multi-physics problem to be solved using a JFNK technique, is nevertheless a major undertaking. The possibility to use a linearly-approximated preconditioner, knowing the structure of the desired preconditioner, was also proposed. It was found to be an interesting alternative when the development of an analytical Jacobian is either too difficult (due to complex models being used in the problem being solved) or when the models are not accessible (“black-box” approach).
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| 5. |
- Demaziere, Christophe, 1973, et al.
(författare)
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JFNK preconditioning for coupled BWR calculations
- 2018
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Ingår i: International Conference on Physics of Reactors, PHYSOR 2018: Reactor Physics Paving the Way Towards More Efficient Systems. ; Part F168384-2, s. 1365-1376
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Konferensbidrag (refereegranskat)abstract
- In this paper, a one-dimensional Boiling Water Reactor (BWR) model in steady-state conditions is developed. The model accounts for neutron transport, fluid dynamics, heat transfer and the interdependences between the various physics. The modelling assumptions were chosen so that the physics of BWRs could be properly accounted for with an as simple as possible model. The model is thereafter used to study the effect of preconditioning when a Jacobian-Free Newton Krylov (JFNK) method is used to solve the system of equations. Preconditioning is a key aspect in any JFNK method. By clustering the eigenvalues of the system of equations, a preconditioner is expected to drastically reduce the number of iterations. Nevertheless, the design of an efficient preconditioner is a far from trivial task. Using the developed model, different preconditioning alternatives are tested. It is demonstrated that an efficient preconditioner is found to have the following characteristics: separate preconditioning of the neutron transport problem, no preconditioning of the heat transfer problem, preconditioning of the fluid dynamics problem where the cross-dependencies between the void fraction and the phasic velocities are resolved and where the pressure field is treated independently. This paper thus provides guidelines about how to develop an efficient preconditioner for coupled BWR physics.
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| 6. |
- Gonzalez-Pintor, Sebastian, 1983, et al.
(författare)
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QZ-decomposition for matrix-free sweep with high order DG-FEM
- 2017
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Ingår i: Int. Conf. Mathematics & Computational Methods Applied to Nuclear Science & Engineering (M&C 2017), Jeju, Korea, April 16-20, 2017.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This work deals with the acceleration of the transport sweep for a discrete ordinates formulation of the neutron transport equation. In particular, we focus on accelerating a matrix-free version of the algorithm. The algorithmic complexity of a naive version of the transport sweep is studied, and a preprocessing technique based on a QZ-decomposion of the matrices composing the sweep is proposed. This technique is not purely matrix free, but we will see that the memory requirements for this approach is negligible in comparison with a full inversion of the streaming operator. The proposed technique is tailored for high order Finite Element Method on regular Cartesian meshes, where the local problems are dense matrices of small size, but with minor modification it can be extended to regular triangular meshes and for non-matching grids with isotropic refinements. The extension to more general geometries requires simultaneous triangularization of more than two matrices at once. The performance of the proposed acceleration is analysed in algorithmic complexity with respect to the number of iterations, and then it is used to predict the required CPU-time to solve the problem. These predictions are tested with at 2D pin-by-pin problem consisting of four assemblies, and the predictions show good agreement with the measured CPU-time for a range of polynomial degrees.
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| 7. |
- Mani, Kevin, et al.
(författare)
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Screening for Abdominal Aortic Aneurysm among Patients Referred to the Vascular Laboratory is Cost-effective
- 2010
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 39:2, s. 208-216
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Tidskriftsartikel (refereegranskat)abstract
- Screening for abdominal aortic aneurysm (AAA) in high-risk groups has been recommended based on a high prevalence of disease, while being questioned due to a high frequency of co-morbidities and inferior life-expectancy. We evaluated the long-term outcome and the cost-effectiveness of selective AAA screening among patients referred to the vascular laboratory for arterial examination. METHODS: A total of 5924 patients, referred to the vascular laboratory of a university hospital, were screened for AAA with ultrasound (definition: slashed circle>/=30mm), 1993-2005. Outcome data were gathered through hospital records and the national population registry. A Markov model was used for health-economic evaluation. RESULTS: An AAA was detected in 181 patients (mean age 72.8 years), of whom 21.5% underwent elective repair (perioperative mortality 5.1%) after 7.5 years of follow-up. Four of six patients diagnosed with AAA rupture were operated upon. Relative 5-year survival compared with the general Swedish population, controlled for age and sex, was 80.4% (95% confidence interval (CI): 70.8-88.8). The cost-effectiveness was robust in base-case (11 084 Euro/life year gained) and in sensitivity analyses of prevalence, cost and survival. CONCLUSIONS: Patients in whom AAA was detected at selective screening had inferior long-term survival and were operated on less frequently, compared with AAA patients described in previous studies. Yet, selective screening at the vascular laboratory was cost-effective.
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| 8. |
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| 9. |
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| 10. |
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Nation i ombildning : essäer om 2000-talets Sverige
- 2018. - 1
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- Sverige har länge betraktats som en demokratisk förebild och ett öppet och solidariskt välfärdssamhälle. Under 2000-talet har social ojämlikhet och boendesegregering ökat, åtföljd av rasism och en allt mer restriktiv flyktingpolitik. Sverige är en nation i ombildning. Åtstramningspolitik och högerpopulism har fått bred förankring i partipolitiken. Samtidigt uppstår motrörelser, där civilsamhälleliga aktörer kräver en fördjupad demokrati och social rättvisa. Vi står inför ett skifte. Kommer en nyliberal ekonomisk politik att smälta samman med en auktoritär, rasistisk populism? Eller är de nya rörelserna en öppning mot ett mer inkluderande, jämlikt och rättvist samhälle, där visionen för framtiden byggs på hopp och optimism — inte rädsla och hot?
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| 11. |
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Reimagineering the Nation : essays on twenty-first-century Sweden
- 2017
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- This collection of essays offers a critical analysis of neoliberal transformation as it has unfolded in Sweden, long regarded as exemplary in terms of social welfare, equality and an inclusive multicultural democracy. The book presents a multidisciplinary exposition on Sweden, seen in a wider European perspective. It addresses changing frameworks of citizenship, welfare and democracy, migration and asylum, urban segregation and labour market segmentation and processes of securitization. It illuminates intersecting dimensions of class, gender and racialization and juxtaposes xenophobic populism with new social justice and antiracist movements on a changing political stage. Addressing a growing alignment with retrogressive illiberal policies across Europe, the volume exposes the reach of the adverse direction in which European "integration" is currently heading.
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| 12. |
- Rundqvist, Robert, 1974, et al.
(författare)
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Simulation of Spray Painting in Automotive Industry
- 2010
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Ingår i: Numerical Mathematics and Advanced Applications 2009 (Proceedings of ENUMATH 2009, the 8th European Conference on Numerical Mathematics and Advanced Applications, Uppsala, July 2009). - Berlin, Heidelberg : Springer Berlin Heidelberg. ; Part 2, s. 769-777
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Konferensbidrag (refereegranskat)
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| 13. |
- Schierup, Carl-Ulrik, 1948-, et al.
(författare)
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Nation i ombildning
- 2018. - 1
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Ingår i: Nation i ombildning. - Stockholm : Boréa Bokförlag. - 9789189140950 ; , s. 7-30
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Sverige har länge betraktats som en demokratisk förebild och ett öppet och solidariskt välfärdssamhälle. Under 2000-talet har social ojämlikhet och boendesegregering ökat, åtföljd av rasism och en allt mer restriktiv flyktingpolitik. Sverige är en nation i ombildning. Åtstramningspolitik och högerpopulism har fått bred förankring i partipolitiken. Samtidigt uppstår motrörelser, där civilsamhälleliga aktörer kräver en fördjupad demokrati och social rättvisa. Vi står inför ett skifte. Kommer en nyliberal ekonomisk politik att smälta samman med en auktoritär, rasistisk populism? Eller är de nya rörelserna en öppning mot ett mer inkluderande, jämlikt och rättvist samhälle, där visionen för framtiden byggs på hopp och optimism — inte rädsla och hot?
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| 14. |
- Schierup, Carl-Ulrik, 1948-, et al.
(författare)
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“Race” and the upsurge of antagonistic popular movements in Sweden
- 2018
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Ingår i: Ethnic and Racial Studies. - : Routledge. - 0141-9870 .- 1466-4356. ; 41:10, s. 1837-1854
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Tidskriftsartikel (refereegranskat)abstract
- Across a crisis-stricken Europe battles rage for post-neoliberal hegemony, with“race” and “austerity” as central signifiers. One of the places where thefrontlines are most pregnant is Sweden; long perceived as a role model for itswelfare state, cultural equity and social equality. Sweden is, however, facingsocial conflicts following in the tracks of a deep transformation in terms ofwelfare cuts, racialization and growing social polarization, targeting inparticular a disadvantaged migrant and post-migrant population. On thatbackground, the paper focuses on the upsurge of mutually antagonistic popularmovements – “racist” and “anti-racist”. We use Sweden as an exemplary case ofEurope’s present Polanyian moment, reminiscent of the 1930s. Yet, currentupheavals expound, the authors claim, a different configuration of crisis andracism as well as a dissimilar utopia for the imagineering of nation and community.
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| 15. |
- Schierup, Carl-Ulrik, et al.
(författare)
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Reimagineering the nation : crisis and social transformation in 21st century Sweden : an introduction
- 2017
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Ingår i: Reimagineering the nation. - Frankfurt am Main : Peter Lang Publishing Group. - 9783631715185 ; , s. 9-37
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Bokkapitel (refereegranskat)abstract
- While for long being known as an international role model of tolerant multiculturalism and ethno-national diversity, Sweden is presently characterized by restrictive refuge policies, growing right wing populism but also resistance among civil society actors spearheaded by a variety of social justice movements. This first chapter introduces and contextualises the following 13 chapters of the book. They discuss Sweden's current transformation from varying, but complementary, perspectives. Their authors set focus on the present crossroad in the country's development, in terms of labour, citizenship racism and social exclusion, gender and immigration policy.
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| 16. |
- Tovatt, Caroline, 1968-
(författare)
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Erkännandets Janusansikte : Det sociala kapitalets betydelse i arbetslivskarriärer
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I denna studie undersöks de informella processerna i rekryteringen, speciellt innebörden av olika former av socialt kapital. I fokus står de värden som tillskrivs utbildningar, arbetslivserfarenheter och kontakter. Det uttrycks genom frågor som hur, var, vem och varför snarare än om lediga tjänster tillsätts via kontakter. Centralt är att förstå det sociala kapitalets betydelse för erkännandet och misskännande i arbetslivet. Resultatet visar att erkännandet inte kan manipuleras, styras eller tvingas fram – det tillskrivs en individ först när man av omgivningen anses värdig. Misskännandet däremot framträder i erkännandet skugga, genom frånvaron av de rätta kontakterna och informell kunskap om hur man tar sig in och fram i arbetslivet. Analysen sker med stöd av Pierre Bourdieu's analytiska verktygslåda. Studien är kvalitativ och det empiriska materialet består av arbetslivsberättelser med individer som befinner sig i olika faser i sitt arbetsliv: unga människor som arbetar inom snabbmatsindustrin, akademiskt utbildade som arbetar under sin utbildningsnivå (som taxichaufförer eller inom vård och omsorg) och slutligen akademiker som arbetar med kvalificerade arbeten (som journalister eller inom radion/TV). Studien bygger på berättelser om deras arbetsliv och utbildningar.
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| 17. |
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| 18. |
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| 19. |
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| 20. |
- Ålund, Martina, et al.
(författare)
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Selective screening for abdominal aortic aneurysm among patients referred to the vascular laboratory
- 2008
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 35:6, s. 669-74
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Patients examined for peripheral arterial disease at the vascular laboratory, Uppsala University Hospital, are since 1993 screened for abdominal aortic aneurysm (AAA). The objective of this study was to study the prevalence of AAA found at this selective high-risk screening. METHODS: All files in the vascular laboratory were retrospectively reviewed. Of 9296 persons examined with arterial duplex between 1993 and October 2005, 5924 were screened for AAA. The primary target vessel was the carotid arteries in 3772 subjects, the renal arteries in 1529 subjects and the lower extremity arteries in 1457 subjects. An AAA was defined as an infrarenal aortic diameter >/=30mm. RESULTS: 179 subjects were found to have an AAA. In a logistic regression model male gender, age and duplex-verified arterial stenosis were independently associated with AAA (odds ratio 3.2, 2.0/20 years and 2.0, respectively, p<0.001). In men <60 years the AAA prevalence was 0.9% (95% confidence interval 0.2-1.6%) when arterial stenosis was absent and 1.5% (0.0-3.2%) when present. In men >/=60 years the AAA prevalence was 4.0% (3.0-5.1%) when no arterial stenosis was found and 7.3% (5.7-8.9%) when found. The corresponding prevalences in women were 0%, 0%, 1.2% (0.5-1.8%), and 3.1% (1.9-4.3%), respectively. CONCLUSIONS: Men >/=60 years referred for arterial examination have a significant risk of having an AAA while only women >/=65 years with a duplex verified arterial stenosis have a sufficient risk of having an AAA. Studies to evaluate the benefit of selective high-risk screening are warranted.
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