| 1. |
- Dahlbom, L, et al.
(författare)
-
Gender and Overconfidence : Are Girls really overconfident?
- 2011
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Ingår i: Applied Economics Letters. - : Taylor & Francis. - 1350-4851 .- 1466-4291. ; 18:4, s. 325-327
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Tidskriftsartikel (refereegranskat)abstract
- Previous research finds that people are overconfident and that men are more overconfident than women. Using a very precise confidence measure, this article shows, however, that whereas boys are overconfident, girls are actually underconfident regarding their mathematics performance. We conducted a survey where 14-year-old high school students were asked what grade they thought they would get in a mathematics test a week later. These results were then compared with their actual grade. Boys were overconfident about their grades, whereas girls were underconfident.
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| 2. |
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| 3. |
- Jakobsson, Johan, et al.
(författare)
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Long-Term Functional Outcome and Quality of Life After Surgical Evacuation of Spontaneous Supratentorial Intracerebral Hemorrhage: Results from a Swedish Nationwide Cohort
- 2022
-
Ingår i: World Neurosurgery. - : Elsevier BV. - 1878-8750 .- 1878-8769. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate long-term survival, neurologic outcome, and quality of life in patients with spontaneous supratentorial intracerebral hemorrhage (ICH) treated with craniotomy and hematoma evacuation. Methods: A nationwide multicenter retrospective analysis of 341 patients who underwent craniotomy and evacuation of supratentorial ICH between January 1, 2011, and December 31, 2015, was performed. Baseline characteristics associated with 6-month mortality and long-term mortality were investigated. Survivors received a questionnaire about their state of health from which EuroQol 5D (EQ-5D) and modified Rankin scale (mRS) were obtained. Predictors of mortality, unfavorable outcome, and life quality were analyzed. Results: The mean follow-up time was 55.2 months. Predictors of 6-month mortality in multiple regression analysis were age ≥75 years, previous myocardial infarction, lower level of consciousness, and mechanical ventilation. Predictors of long-term mortality were higher age and mechanical ventilation. At follow-up, 49.5% of survivors had a favorable neurologic outcome (mRS ≤3). Predictors of an unfavorable functional outcome were higher age and ICH volume ≥50 mL. The mean EQ-5D health index was 0.719, and the mean EQ-5D visual analog scale score was 53.9. In multiple regression, only a higher mRS score was significantly associated with worse life quality. Conclusions: Knowledge about survival, functional outcome, and life quality as well as their predictors in this specific patient group is previously primarily described in short-term follow-up. This multicenter study provides novel information in the long-term perspective, which is important for improved surgical decision-making and prognostication.
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| 4. |
- Jakobsson, Niklas, 1981-, et al.
(författare)
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Attitudes Toward Same-Sex Marriage: The Case of Scandinavia
- 2013
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Ingår i: Journal of Homosexuality. - : Informa UK Limited. - 0091-8369 .- 1540-3602. ; 60:9, s. 1349-1360
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to examine the variables that explain attitudes toward same-sex marriage. Using recently collected Scandinavian data (from Norway and Sweden) with a high response rate, this study shows that gender, regular participation in religious activities, political ideology, education, whether the respondent lived in the capital city, and attitudes toward gender equality were important for attitudes toward same-sex marriage. Age and income were not important for attitudes toward same-sex marriage. Although both Norwegians and Swedes clearly favor same-sex marriage, Swedes are significantly more positive than Norwegians.
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| 5. |
- Jansson, Andreas, et al.
(författare)
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Range-based radar model structure selection
- 2021
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Ingår i: 28th European Signal Processing Conference, EUSIPCO 2020 - Proceedings. - 2219-5491. - 9789082797053 ; 2021-January, s. 2269-2273
-
Konferensbidrag (refereegranskat)abstract
- In this work, we study under which circumstances it is appropriate to use simplified models for range determination using radar. Typically, pulsed radar systems result in the backscattered, demodulated, and matched signal having a chirp signal structure, with the frequency rate being related to the range to the reflecting target and the relative velocity of the transmitter and reflector. Far from the target, and at low relative velocities, one may achieve preferable location estimates by neglecting the frequency rate, treating the received signal as being purely sinusoidal, whereas at close range, neglecting the frequency rate notably reduces the achievable performance. Using misspecified estimation theory, we derive a lower bound of the achievable performance when neglecting the true signal structure, and show at which ranges one model is preferable to the other. Numerical results from a mm-wave radar system illustrate the results.
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| 6. |
- Jansson, Andreas, et al.
(författare)
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Robust Localization of Close-Range Radar Reflections
- 2023
-
Ingår i: Conference Record of the 57th Asilomar Conference on Signals, Systems and Computers, ACSSC 2023. - 9798350325744 ; , s. 549-553
-
Konferensbidrag (refereegranskat)abstract
- In order to allow for a computationally efficient estimation of radar reflections, one commonly assumes the reflecting target to be in the far-field of the sensing array, such that the impinging wavefront is modeled as a linear phase-shift along the array. This works well in most radar scenarios, but causes significant performance degradation for close-range radar systems, wherein the curvature of the impinging wavefront may not be neglected. In this work, we examine how the used far-field assumption limits the resulting performance, illustrating how the (misspecified) Cramér-Rao lower bound (CRLB), taking the model mismatch into account, significantly devi-ates from the true CRLB for close-range targets. We further introduce a robust estimator that allows for the waveform cur-vature, showing that this computationally efficient estimator allows for superior performance for close-range reflectors.
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| 7. |
- Ragnarsson, Oskar, 1971, et al.
(författare)
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Illness perspectives in patients with primary aldosteronism.
- 2022
-
Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 17:11
-
Tidskriftsartikel (refereegranskat)abstract
- The burden of symptoms and treatment in patients with primary aldosteronism (PA), as well as the patients' experience of the health care is sparsely studied. The objectives of this study were to describe symptoms considered to be the most troublesome by patients with PA, and to explore health related worries and expectations following treatment.This was an explorative qualitative study where 25 patients with PA, diagnosed between 2017 and 2019, were included; 13 patients who had undergone adrenalectomy and 12 who were receiving medical treatment. Data was collected during six group interviews and analyzed using a thematic approach.Three main themes were identified: 1) Distress of the past, where the most important issues were struggle to receive a correct diagnosis, impaired well-being and the consumption of a large number of tablets, 2) Satisfaction after receiving a correct diagnosis, both in patients with unilateral and bilateral disease, but also dissatisfaction with lack of information about the disease, and 3) Future concerns, where worries about the long-term effects of PA on health in general dominated.Our findings illustrate several important issues related to PA where improvements in patient care are needed, including actions aiming at shortening the long diagnostic delay, a thorough information to the patients about the disease is of great importance, and that all patients with PA, regardless of treatment, would benefit from a structured long-term follow-up.
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| 8. |
- Steg, Linda, et al.
(författare)
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A Research Agenda to Better Understand the Human Dimensions of Energy Transitions
- 2021
-
Ingår i: Frontiers in Psychology. - : Frontiers Media S.A.. - 1664-1078. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The Social Sciences and Humanities (SSH) have a key role to play in understanding which factors and policies would motivate, encourage and enable different actors to adopt a wide range of sustainable energy behaviours and support the required system changes and policies. The SSH can provide critical insights into how consumers could be empowered to consistently engage in sustainable energy behaviour, support and adopt new technologies, and support policies and changes in energy systems. Furthermore, they can increase our understanding of how organisations such as private and public institutions, and groups and associations of people can play a key role in the sustainable energy transition. We identify key questions to be addressed that have been identified by the Platform for Energy Research in the Socio-economic Nexus (PERSON, see person.eu), including SSH scholars who have been studying energy issues for many years. We identify three main research themes. The first research theme involves understanding which factors encourage different actors to engage in sustainable energy behaviour. The second research theme focuses on understanding which interventions can be effective in encouraging sustainable energy behaviour of different actors, and which factors enhance their effects. The third research theme concerns understanding which factors affect public and policy support for energy policy and changes in energy systems, and how important public concerns can best be addressed as to reduce or prevent resistance.
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| 9. |
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| 10. |
- Adalbjörnsson, Stefan, et al.
(författare)
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Conjugate priors for Gaussian emission plsa recommender systems
- 2016
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Ingår i: 2016 24th European Signal Processing Conference, EUSIPCO 2016. - 9780992862657 ; 2016-November, s. 2096-2100
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Konferensbidrag (refereegranskat)abstract
- Collaborative filtering for recommender systems seeks to learn and predict user preferences for a collection of items by identifying similarities between users on the basis of their past interest or interaction with the items in question. In this work, we present a conjugate prior regularized extension of Hofmann's Gaussian emission probabilistic latent semantic analysis model, able to overcome the over-fitting problem restricting the performance of the earlier formulation. Furthermore, in experiments using the EachMovie and MovieLens data sets, it is shown that the proposed regularized model achieves significantly improved prediction accuracy of user preferences as compared to the latent semantic analysis model without priors.
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| 11. |
- Adalbjörnsson, Stefan Ingi, et al.
(författare)
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A Sparse Approach for Estimation of Amplitude Modulated Sinusoids
- 2014
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Konferensbidrag (refereegranskat)abstract
- We consider the problem of spectral analysis of signals composed of sums of multiple amplitude modulated, possibly harmonically related, sinusoids using a sparse approach. By separating the nonlinear frequency variables using a dictionary of possible frequency components as well as a spline basis for the amplitude modulation, results in a convex criterion which can be efficiently solved without worrisome local minima. The resulting method makes no model order assumption and automatically estimates both the signal parameters and their amplitude modulations
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| 12. |
- Adalbjörnsson, Stefan Ingi, et al.
(författare)
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Efficient Block and Time-Recursive Estimation of Sparse Volterra Systems
- 2012
-
Ingår i: 2012 IEEE Statistical Signal Processing Workshop (SSP), Proceedings of. - 9781467301831 ; , s. 173-176
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Konferensbidrag (refereegranskat)abstract
- We investigate the application of non-convex penalized least squares for parameter estimation in the Volterra model. Sparsity is promoted by introducing a weighted !q penalty on the parameters and efficient batch and time recursive algorithms are devised based on the cyclic coordinate descent approach. Numerical examples illustrate the improved performance of the proposed algorithms as compared the weighted !1 norm.
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| 13. |
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| 14. |
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| 15. |
- Adalbjörnsson, Stefan Ingi, et al.
(författare)
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Estimating Periodicities in Symbolic Sequences Using Sparse Modeling
- 2015
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Ingår i: IEEE Transactions on Signal Processing. - 1053-587X. ; 63:8, s. 2142-2150
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we propose a method for estimating statistical periodicities in symbolic sequences. Different from other common approaches used for the estimation of periodicities of sequences of arbitrary, finite, symbol sets, that often map the symbolic sequence to a numerical representation, we here exploit a likelihood-based formulation in a sparse modeling framework to represent the periodic behavior of the sequence. The resulting criterion includes a restriction on the cardinality of the solution; two approximate solutions are suggested—one greedy and one using an iterative convex relaxation strategy to ease the cardinality restriction. The performance of the proposed methods are illustrated using both simulated and real DNA data, showing a notable performance gain as compared to other common estimators.
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| 16. |
- Adalbjörnsson, Stefan Ingi, et al.
(författare)
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High resolution sparse estimation of exponentially decaying two-dimensional signals
- 2014
-
Ingår i: European Signal Processing Conference. - 2219-5491.
-
Konferensbidrag (refereegranskat)abstract
- In this work, we consider the problem of high-resolution estimation of the parameters detailing a two-dimensional (2-D) signal consisting of an unknown number of exponentially decaying sinusoidal components. Interpreting the estimation problem as a block (or group) sparse representation problem allows the decoupling of the 2-D data structure into a sum of outer-products of 1-D damped sinusoidal signals with unknown damping and frequency. The resulting non-zero blocks will represent each of the 1-D damped sinusoids, which may then be used as non-parametric estimates of the corresponding 1-D signals; this implies that the sought 2-D modes may be estimated using a sequence of 1-D optimization problems. The resulting sparse representation problem is solved using an iterative ADMM-based algorithm, after which the damping and frequency parameter can be estimated by a sequence of simple 1-D optimization problems.
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| 17. |
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| 18. |
- Adalbjörnsson, Stefan Ingi, et al.
(författare)
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Multi-Pitch Estimation Exploiting Block Sparsity
- 2015
-
Ingår i: Signal Processing. - : Elsevier BV. - 0165-1684. ; 109:April, s. 236-247
-
Tidskriftsartikel (refereegranskat)abstract
- We study the problem of estimating the fundamental frequencies of a signal containing multiple harmonically related sinusoidal components using a novel block sparse signal representation. An efficient algorithm for solving the resulting optimization problem is devised exploiting a novel variable step-size alternating direction method of multipliers (ADMM). The resulting algorithm has guaranteed convergence and shows notable robustness to the f 0 vs f0/2f0/2 ambiguity problem. The superiority of the proposed method, as compared to earlier presented estimation techniques, is demonstrated using both simulated and measured audio signals, clearly indicating the preferable performance of the proposed technique.
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| 19. |
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| 20. |
- Adalbjörnsson, Stefan Ingi, et al.
(författare)
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Sparse Estimation Of Spectroscopic Signals
- 2011
-
Ingår i: European Signal Processing Conference. - 2219-5491. ; 2011, s. 333-337
-
Konferensbidrag (refereegranskat)abstract
- This work considers the semi-parametric estimation of sparse spec- troscopic signals, aiming to form a detailed spectral representation of both the frequency content and the spectral line widths of the oc- curring signals. Extending on the recent FOCUSS-based SLIM al- gorithm, we propose an alternative prior for a Bayesian formulation of this sparse reconstruction method, exploiting a proposed suitable prior for the noise variance. Examining three common models for spectroscopic signals, the introduced technique allows for reliable estimation of the characteristics of these models. Numerical sim- ulations illustrate the improved performance of the proposed tech- nique.
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| 21. |
- Adalbjörnsson, Stefan Ingi, et al.
(författare)
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Sparse Localization of Harmonic Audio Sources
- 2016
-
Ingår i: IEEE/ACM Transactions on Audio, Speech, and Language Processing. - 2329-9290. ; 24:1, s. 117-129
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we propose a novel method for estimating the locations of near- and/or far-field harmonic audio sources impinging on an arbitrary, but calibrated, sensor array. Using a joint pitch and location estimation formed in two steps, we first estimate the fundamental frequencies and complex amplitudes under a sinusoidal model assumption, whereafter the location of each source is found by utilizing both the difference in phase and the relative attenuation of the magnitude estimates. As audio recordings often consist of multi-pitch signals exhibiting some degree of reverberation, where both the number of pitches and the source locations are unknown, we propose to use sparse heuristics to avoid the necessity of detailed a priori assumptions on the spectral and spatial model orders. The method’s performance is evaluated using both simulated and measured audio data, with the former showing that the proposed method achieves near-optimal performance, whereas the latter confirms the method’s feasibility when used with real recordings.
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| 22. |
- Aggelopoulos, Kostas, et al.
(författare)
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Efficient Implementation of the IAA-based Magnitude Squared Coherence Estimator
- 2011
-
Ingår i: Digital Signal Processing (DSP), 2011 17th International Conference on. - 9781457702730
-
Konferensbidrag (refereegranskat)abstract
- Recently, a novel Magnitude Squared Coherence (MSC) estimator was proposed using the Iterative Adaptive Approach (IAA) algorithm. In this paper, we present a computationally efficient implementation of this estimator, exploiting the inherently low displacement rank of the necessary products of Toeplitz-like matrices, thereby allowing for the development of appropriate Gohberg-Semencul (GS) representations of these matrices. Together with relevant data dependent trigonometric polynomials, the presented implementation offers a substantial computational reduction as compared to earlier implementations. Numerical simulations along with theoretical complexity estimations illustrate the performance of the proposed algorithm.
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| 23. |
- Ahgren, Per, et al.
(författare)
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A study of doubletalk detection performance in the presence of acoustic echo path changes
- 2006
-
Ingår i: IEEE transactions on consumer electronics. - Uppsala Univ, Dept Syst & Control, Informat Control, SE-75105 Uppsala, Sweden. Karlstad Univ, Dept Elect Engn, SE-65188 Karlstad, Sweden.. - 0098-3063 .- 1558-4127. ; 52:2, s. 515-522
-
Tidskriftsartikel (refereegranskat)abstract
- An efficient and well-performing double-talk detection (DTD) algorithm is a vital part of a practically working acoustic echo canceller. However, recent algorithms are typically evaluated using a static time-invariant room acoustic impulse response, omitting a proper treatment of the case when the acoustic path is changing. In this work, we introduce a common framework to objectively evaluate how path changes affect the DTD performance. Via extensive numerical simulations, we conclude that the main factor in acoustic path changes affecting the DTD performance for some of the more common DTD algorithms is variations in the damping of the acoustic path.
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| 24. |
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| 25. |
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| 26. |
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| 27. |
- Altstadt, S.G., et al.
(författare)
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B-13,B-14(n,gamma) via Coulomb Dissociation for Nucleosynthesis towards the r-Process
- 2014
-
Ingår i: Nuclear Data Sheets. - : Elsevier BV. - 1095-9904 .- 0090-3752. ; 120, s. 197-200
-
Konferensbidrag (refereegranskat)abstract
- Radioactive beams of 14,15B produced by fragmentation of a primary 40Ar beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/R3B setup. Preliminary results for the Coulomb dissociation cross sections as well as for the astrophysically interesting inverse reactions, 13,14B(n,γ), are presented.
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| 28. |
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| 29. |
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| 30. |
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| 31. |
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| 32. |
- Alty, Stephen R., et al.
(författare)
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Efficient implementation of the time-recursive Capon and APES spectral estimators
- 2004
-
Ingår i: EUSIPCO <em>2004</em>. - 3200001658 ; , s. 1269-1272
-
Konferensbidrag (refereegranskat)abstract
- A method for the computationally efficient sliding window time-updating of the Capon and APES spectral estimators based on the time-variant displacement structure of the data covariance matrix is presented. The proposed algorithm forms a natural extension of the computationally most efficient algorithm to date, and offers a significant computationalgain as compared to the computational complexity associated with the batch re-evaluation of the spectral estimates for each time-update.
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| 33. |
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| 34. |
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| 35. |
- Andersson, Björn O, 1982, et al.
(författare)
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A Modified TAB Model for Simulation of Atomization in Rotary Bell Spray Painting
- 2013
-
Ingår i: Journal of Mechanical Engineering and Automation. - 2163-2413. ; 3:2, s. 54-61
-
Tidskriftsartikel (refereegranskat)abstract
- The Rotary bell spray applicator technique is commonly used in the automotive industry for paint application because of its high transfer efficiency and high-quality result. The bell spins rapidly around its axis with a tangential velocity at the edge in the order of 100 m/s. The paint falls off the edge and enters the air with a large relative velocity, driving the atomization into small droplets where the resulting size distribution depends on the process conditions. Especially the rotation speed of the bell is an important parameter governing the size distribution. The main research question in this work is to investigate if the Taylor Analogy Breakup (TAB) model can be used to predict the resulting droplet size distributions in spray painting. As the paint is a viscous fluid a modification of the TAB model taking non-linear effects of large viscosity into account is proposed. The parameters in the breakup model are tuned by optimization to match droplet size distributions obtained in CFD simulations with measured ones. Results are presented for three cases with rotation speeds from 30 to 50 thousand RPM where the full droplet size distributions are compared with measurements. Good results are obtained for all three cases where the simulated size distributions compare well to measurements over a wide range of droplet sizes. The TAB method is able to quantitatively predict the result of the breakup process and can be used in a preprocessing stage of a full spray painting simulation, thereby reducing the need for costly and cumbersome measurements.
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| 36. |
- Andersson, Björn O, 1982, et al.
(författare)
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Modeling Surface Tension in SPH by Interface Reconstruction using Radial Basis Functions
- 2010
-
Ingår i: Proceedings of the 5th International SPHERIC Workshop, 22-25 June 2010, Manchester, U.K., edited by B. D. Rogers. ; , s. 7-14
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A novel method for reconstructing the interface between two fluids is described and evaluated. The method uses a different basis for approximating the color function than what is common practice in SPH simulations. The key feature of the new method is the ability to omit small length scale structures in order to obtain a smoother representation. A smoother interface is more suitable to derive a surface tension force from, as the magnitude of the force is proportional to the curvature which is related to the second derivative along the interface.
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| 37. |
- Andersson, Björn O, 1982, et al.
(författare)
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Modified TAB Model for Viscous Fluids applied to Breakup in Rotary Bell Spray Painting
- 2012
-
Ingår i: ICLASS 2012 - 12th International Conference on Liquid Atomization and Spray Systems.
-
Konferensbidrag (refereegranskat)abstract
- The Taylor Analogy Breakup (TAB) model is applied to droplet breakup in rotary bell spray painting commonly used in the automotive industry. The bell spins rapidly around its axis with a tangential velocity at the edge in the order of 100 m/s. The paint falls off the edge and enters the air with a large relative velocity, driving the atomization. The paint is a viscous fluid and a modification of the TAB model taking non-linear effects of large viscosity into account is described. The parameters in the breakup model are tuned to match droplet size distributions obtained in CFD simulations with measured ones. Results are presented for three cases with rotation speeds from 30 to 50 thousand RPM where the full droplet size distributions are compared with measurements. Good results are obtained for all three cases where the simulated size distributions compare well to measurements over a wide range of droplet sizes. The obtained results can be used in a preprocessing stage of a full spray painting simulation thereby reducing the need for costly and cumbersome measurements.
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| 38. |
- Andersson, Lisa, et al.
(författare)
-
Discrimination in the Norwegian Housing Market : Class, Sex and Ethnicity
- 2012
-
Ingår i: Land Economics. - Madison : University of Wisconsin Press. - 0023-7639 .- 1543-8325. ; 88:2, s. 233-240
-
Tidskriftsartikel (refereegranskat)abstract
- We test for gender, class, and ethnic discrimination in the Norwegian rental housing market by using fake application letters. Females, individuals with high job status, and ethnic Norwegians are more likely to receive positive responses. For example, being an Arabic man and working in a warehouse is associated with a 25 percentage point lower probability of receiving a positive response when showing interest in an apartment, as compared to an ethnically Norwegian female economist. We conclude that gender, class, and ethnic discrimination do exist in the Norwegian housing market, and ethnic discrimination seems to be the most prevalent form of discrimination.
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| 39. |
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| 40. |
- Angelopoulos, Kostas, et al.
(författare)
-
Computationally Efficient Capon- and APES-based Coherence Spectrum Estimation
- 2012
-
Ingår i: IEEE Transactions on Signal Processing. - 1053-587X. ; 60:12, s. 6674-6681
-
Tidskriftsartikel (refereegranskat)abstract
- The coherence spectrum is of notable interest as a bivariate spectral measure in a variety of application, and the topic has lately attracted interest with the recent formulation of several ligh-resolution data adaptive estimators. In this work, we further this development with the presentation of computationally efficient implementations of the Caponand APE S-based MSC estimators. The presented implementations furthers the recent development of exploiting the estimators’ inherently low displacement rank of the necessary products of Toeplitz-like matrices to include also the required cross-correlation covariance matrices for the mentioned coherence algorithms. Numerical simulations together with theoretical complexity measures illustrate the performance of the proposed implementations.
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| 41. |
- Angelopoulos, Kostas, et al.
(författare)
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Computationally Efficient Sparsity-Inducing Coherence Spectrum Estimation of Complete and Non-Complete Data Sets
- 2013
-
Ingår i: Signal Processing. - : Elsevier BV. - 0165-1684. ; 93:5, s. 1221-1234
-
Tidskriftsartikel (refereegranskat)abstract
- The magnitude squared coherence (MSC) spectrum is an often used frequency-dependent measure for the linear dependency between two stationary processes, and the recent literature contain several contributions on how to form high-resolution data-dependent and adaptive MSC estimators, and on the efficient implementation of such estimators. In this work, we further this development with the presentation of computationally efficient implementations of the recent iterative adaptive approach (IAA) estimator, present a novel sparse learning via iterative minimization (SLIM) algorithm, discuss extensions to two-dimensional data sets, examining both the case of complete data sets and when some of the observations are missing. The algorithms further the recent development of exploiting the estimators' inherently low displacement rank of the necessary products of Toeplitz-like matrices, extending these formulations to the coherence estimation using IAA and SLIM formulations. The performance of the proposed algorithms and implementations are illustrated both with theoretical complexity measures and with numerical simulations.
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| 42. |
- Angelopoulos, Kostas, et al.
(författare)
-
Efficient Time Recursive Coherence Spectrum Estimation
- 2012
-
Ingår i: Signal Processing Conference (EUSIPCO), 2012 Proceedings of the 20th European. - 2076-1465 .- 2219-5491. - 9781467310680 ; , s. 425-429
-
Konferensbidrag (refereegranskat)abstract
- The coherence spectrum is of notable interest as a bivariate spectral measure in a variety of application, and the topic has lately attracted notable interest with the recent formulation of several high-resolution data adaptive estimators. In this work, we present computationally efficient time recursive implementations of the recent iterative adaptive approach (IAA) estimator, examining both the case of complete data sets and when some observations are missing. The algorithms continues the recent development of exploiting the estimators’ inherently low displacement rank of the necessary products of Toeplitz-like matrices, extending these to time-updating formulations for the IAA-based coherence estimation algorithm. Numerical simulations together with theoretical complexity measures illustrate the performance of the proposed algorithm.
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| 43. |
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| 44. |
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| 45. |
- Bergh, Andreas, et al.
(författare)
-
Modern mikroekonomi : Marknad, politik och välfärd
- 2022. - 5
-
Bok (populärvet., debatt m.m.)abstract
- Den här boken ger en pedagogisk och detaljerad genomgång av den mikroekonomi som varit nationalekonomins kärna under snart 100 år: utbud och efterfrågan, nyttoteori och vinstmaximering. Men författarna sätter också in teorin i ett större sammanhang, där institutioner, beteendeekonomi och politik beaktas och analyseras. Målet är att skapa förståelse för hur marknadsekonomin fungerar, men även att ge läsaren verktyg för att analysera statens roll i samhället och vilka institutioner som krävs för att en fungerande marknadsekonomi ska uppstå. Denna femte upplaga har reviderats och uppdaterats genomgående, bland annat med nya avsnitt om plattformsföretag och konkurrens på internet. Dessutom har många övningar med lösningar lagts till och gjorts om.
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| 46. |
- Bergman, Erik, et al.
(författare)
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BERT based natural language processing for triage of adverse drug reaction reports shows close to human-level performance
- 2023
-
Ingår i: PLOS Digital Health. - : Public Library of Science (PLoS). - 2767-3170. ; 2:12
-
Tidskriftsartikel (refereegranskat)abstract
- Post-marketing reports of suspected adverse drug reactions are important for establishing the safety profile of a medicinal product. However, a high influx of reports poses a challenge for regulatory authorities as a delay in identification of previously unknown adverse drug reactions can potentially be harmful to patients. In this study, we use natural language processing (NLP) to predict whether a report is of serious nature based solely on the free-text fields and adverse event terms in the report, potentially allowing reports mislabelled at time of reporting to be detected and prioritized for assessment. We consider four different NLP models at various levels of complexity, bootstrap their train-validation data split to eliminate random effects in the performance estimates and conduct prospective testing to avoid the risk of data leakage. Using a Swedish BERT based language model, continued language pre-training and final classification training, we achieve close to human-level performance in this task. Model architectures based on less complex technical foundation such as bag-of-words approaches and LSTM neural networks trained with random initiation of weights appear to perform less well, likely due to the lack of robustness that a base of general language training provides.
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| 47. |
- Björk, Marcus, 1985-
(författare)
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Contributions to Signal Processing for MRI
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Magnetic Resonance Imaging (MRI) is an important diagnostic tool for imaging soft tissue without the use of ionizing radiation. Moreover, through advanced signal processing, MRI can provide more than just anatomical information, such as estimates of tissue-specific physical properties.Signal processing lies at the very core of the MRI process, which involves input design, information encoding, image reconstruction, and advanced filtering. Based on signal modeling and estimation, it is possible to further improve the images, reduce artifacts, mitigate noise, and obtain quantitative tissue information.In quantitative MRI, different physical quantities are estimated from a set of collected images. The optimization problems solved are typically nonlinear, and require intelligent and application-specific algorithms to avoid suboptimal local minima. This thesis presents several methods for efficiently solving different parameter estimation problems in MRI, such as multi-component T2 relaxometry, temporal phase correction of complex-valued data, and minimizing banding artifacts due to field inhomogeneity. The performance of the proposed algorithms is evaluated using both simulation and in-vivo data. The results show improvements over previous approaches, while maintaining a relatively low computational complexity. Using new and improved estimation methods enables better tissue characterization and diagnosis.Furthermore, a sequence design problem is treated, where the radio-frequency excitation is optimized to minimize image artifacts when using amplifiers of limited quality. In turn, obtaining higher fidelity images enables improved diagnosis, and can increase the estimation accuracy in quantitative MRI.
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| 48. |
- Blomqvist, Christopher, et al.
(författare)
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Joint Handwritten Text Recognition and Word Classification for Tabular Information Extraction
- 2022
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Ingår i: 2022 26th International Conference on Pattern Recognition (ICPR). - 9781665490634 - 9781665490627 ; , s. 1564-1570
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a system for extracting tabular information from loosely structured handwritten documents. The system consists of three parts, (i) a u-net like CNN-based method for text detection and segmentation, (ii) a new attention-based method for simultaneous text recognition and classification of word-parts, and (iii) a method for matching the word parts into a tabular structure for each entry. A key contribution is the observation that the new attention-based recognition and classification module makes it possible for improved spatial analysis of the tabular information. The method is evaluated on a unique historical document: The Swedish Wealth Tax of 1571, consisting of 11,453 pages of hand-written tax records. The evaluation shows that the system provides a significant improvement to the state-of-the-art to the problem of tabular extraction from loosely structured historical documents.
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| 49. |
- Blomqvist, Christopher, et al.
(författare)
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Reading the ransom: Methodological advancements in extracting the Swedish Wealth Tax of 1571
- 2023
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Ingår i: Explorations in Economic History. - : Elsevier BV. - 0014-4983. ; 87
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Tidskriftsartikel (refereegranskat)abstract
- We describe a deep learning method to read hand-written records from the 16th century. The method consists of a combination of a segmentation module and a Handwritten Text Recognition (HTR) module. The transformer-based HTR module exploits both language and image features in reading, classifying and extracting the position of each word on the page. The method is demonstrated on a unique historical document: The Swedish Wealth Tax of 1571. Results suggest that the segmentation module performs significantly better than the lay-out analysis implemented in state-of-the art programs, enabling us to trace many more text blocks correctly on each page. The HTR module has a low character error rate (CER), in addition to being able to classify words and help organize them into tabular formats. By demonstrating an automated process to transform loosely structured handwritten information from the 16th century into organized tables, our method should interest economic historians seeking to digitize and organize quantitative material from pre-industrial periods.
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| 50. |
- Blunden, Jessica, et al.
(författare)
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State of the Climate in 2012
- 2013
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 94:8, s. S1-S258
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Tidskriftsartikel (refereegranskat)abstract
- For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional climate conditions around the globe. A weak La Ni a dissipated to ENSOneutral conditions by spring, and while El Nino appeared to be emerging during summer, this phase never fully developed as sea surface temperatures in the eastern conditions. Nevertheless, other large-scale climate patterns and extreme weather events impacted various regions during the year. A negative phase of the Arctic Oscillation from mid-January to early February contributed to frigid conditions in parts of northern Africa, eastern Europe, and western Asia. A lack of rain during the 2012 wet season led to the worst drought in at least the past three decades for northeastern Brazil. Central North America also experienced one of its most severe droughts on record. The Caribbean observed a very wet dry season and it was the Sahel's wettest rainy season in 50 years. Overall, the 2012 average temperature across global land and ocean surfaces ranked among the 10 warmest years on record. The global land surface temperature alone was also among the 10 warmest on record. In the upper atmosphere, the average stratospheric temperature was record or near-record cold, depending on the dataset. After a 30-year warming trend from 1970 to 1999 for global sea surface temperatures, the period 2000-12 had little further trend. This may be linked to the prevalence of La Ni a-like conditions during the 21st century. Heat content in the upper 700 m of the ocean remained near record high levels in 2012. Net increases from 2011 to 2012 were observed at 700-m to 2000-m depth and even in the abyssal ocean below. Following sharp decreases in to the effects of La Ni a, sea levels rebounded to reach records highs in 2012. The increased hydrological cycle seen in recent years continued, with more evaporation in drier locations and more precipitation in rainy areas. In a pattern that has held since 2004, salty areas of the ocean surfaces and subsurfaces were anomalously salty on average, while fresher areas were anomalously fresh. Global tropical cyclone activity during 2012 was near average, with a total of 84 storms compared with the 1981-2010 average of 89. Similar to 2010 and 2011, the North Atlantic was the only hurricane basin that experienced above-normal activity. In this basin, Sandy brought devastation to Cuba and parts of the eastern North American seaboard. All other basins experienced either near-or below-normal tropical cyclone activity. Only three tropical cyclones reached Category 5 intensity-all in Bopha became the only storm in the historical record to produce winds greater than 130 kt south of 7 N. It was also the costliest storm to affect the Philippines and killed more than 1000 residents. Minimum Arctic sea ice extent in September and Northern Hemisphere snow cover extent in June both reached new record lows. June snow cover extent is now declining at a faster rate (-17.6% per decade) than September sea ice extent (-13.0% per decade). Permafrost temperatures reached record high values in northernmost Alaska. A new melt extent record occurred on 11-12 July on the Greenland ice sheet; 97% of the ice sheet showed some form of melt, four times greater than the average melt for this time of year. The climate in Antarctica was relatively stable overall. The largest maximum sea ice extent since records begain in 1978 was observed in September 2012. In the stratosphere, warm air led to the second smallest ozone hole in the past two decades. Even so, the springtime ozone layer above Antarctica likely will not return to its early 1980s state until about 2060. Following a slight decline associated with the global 2 emissions from fossil fuel combustion and cement production reached a record 9.5 +/- 0.5 Pg C in 2011 and a new record of 9.7 +/- 0.5 Pg C is estimated for 2012. Atmospheric CO2 concentrations increased by 2.1 ppm in 2012, to 392.6 ppm. In spring 2012, 2 concentration exceeded 400 ppm at 7 of the 13 Arctic observation sites. Globally, other greenhouse gases including methane and nitrous oxide also continued to rise in concentration and the combined effect now represents a 32% increase in radiative forcing over a 1990 baseline. Concentrations of most ozone depleting substances continued to fall.
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