Methods for Optimal Model Fitting and Sensor Calibration

The problem of fitting models to measured data has been studied extensively, not least in the field of computer vision. A central problem in this field is the difficulty in reliably find corresponding structures and points in different images, resulting in outlier data. This thesis presents theoretical results improving the understanding of the connection between model parameter estimation and possible outlier-inlier partitions of data point sets. Using these results a multitude of applications can be analyzed in respects to optimal outlier inlier partitions, optimal norm fitting, and not least in truncated norm sense. Practical polynomial time optimal solvers are derived for several applications, including but not limited to multi-view triangulation and image registration. In this thesis the problem of sensor network self calibration is investigated. Sensor networks play an increasingly important role with the increased availability of mobile, antenna equipped, devices. The application areas can be extended with knowledge of the different sensors relative or absolute positions. We study this problem in the context of bipartite sensor networks. We identify requirements of solvability for several configurations, and present a framework for how such problems can be approached. Further we utilize this framework to derive several solvers, which we show in both synthetic and real examples functions as desired. In both these types of model estimation, as well as in the classical random samples based approaches minimal cases of polynomial systems play a central role. A majority of the problems tackled in this thesis will have solvers based on recent techniques pertaining to action matrix solvers. New application specific polynomial equation sets are constructed and elimination templates designed for them. In addition a general improvement to the method is suggested for a large class of polynomial systems. The method is shown to improve the computational speed by significant reductions in the size of elimination templates as well as in the size of the action matrices. In addition the methodology on average improves the numerical stability of the solvers

Minimal Structure and Motion Problems for TOA and TDOA Measurements with Collinearity Constraints

Structure from sound can be phrased as the problem of determining the position of a number of microphones and a number of sound sources given only the recorded sounds. In this paper we study minimal structure from sound problems in both TOA (time of arrival) and TDOA (time difference of arrival) settings with collinear constraints on e.g. the microphone positions. Three such minimal cases are analyzed and solved with efficient and numerically stable techniques. An experimental validation of the solvers are performed on both simulated and real data. In the paper we also show how such solvers can be utilized in a RANSAC framework to perform robust matching of sound features and then used as initial estimates in a robust non-linear leastsquares optimization

A Unifying Approach to Minimal Problems in Collinear and Planar TDOA Sensor Network Self-Calibration

This work presents a study of sensor network calibration from time-difference-of-arrival (TDOA) measurements for cases when the dimensions spanned by the receivers and the transmitters differ. This could for example be if receivers are restricted to a line or plane or if the transmitting objects are moving linearly in space. Such calibration arises in several applications such as calibration of (acoustic or ultrasound) microphone arrays, and radio antenna networks. We propose a non-iterative algorithm based on recent stratified approaches: (i) rank constraints on modified measurement matrix, (ii) factorization techniques that determine transmitters and receivers up to unknown affine transformation and (iii) determining the affine stratification using remaining non-linear constraints. This results in a unified approach to solve almost all minimal problems. Such algorithms are important components for systems for self-localization. Experiments are shown both for simulated and real data with promising results

Psychosocial predictors of treatment outcome for trauma-affected refugees

Background: The effects of treatment in trials with trauma-affected refugees vary considerably not only between studies but also between patients within a single study. However, we know little about why some patients benefit more from treatment, as few studies have analysed predictors of treatment outcome. Objective: The objective of the study was to examine possible psychosocial predictors of treatment outcome for trauma-affected refugees. Method: The participants were 195 adult refugees with posttraumatic stress disorder (PTSD) who were enrolled in a 6- to 7-month treatment programme at the Competence Centre for Transcultural Psychiatry (CTP), Denmark. The CTP Predictor Index used in the study included 15 different possible outcome predictors concerning the patients’ past, chronicity of mental health problems, pain, treatment motivation, prerequisites for engaging in psychotherapy, and social situation. The primary outcome measure was PTSD symptoms measured on the Harvard Trauma Questionnaire (HTQ). Other outcome measures included the Hopkins Symptom Check List-25, the WHO-5 Well-being Index, Sheehan Disability Scale, Hamilton Depression and Anxiety Scales, the somatisation scale of the Symptoms Checklist-90, Global Assessment of Functioning scales, and pain rated on visual analogue scales. The relations between treatment outcomes and the total score as well as subscores of the CTP Predictor Index were analysed. Results: Overall, the total score of the CTP Predictor Index was significantly correlated to pre- to post treatment score changes on the majority of the ratings mentioned above. While employment status was the only single item significantly correlated to HTQ-score changes, a number of single items from the CTP Predictor Index correlated significantly with changes in depression and anxiety symptoms, but the size of the correlation coefficients were modest. Conclusions: The total score of the CTP Predictor Index correlated significantly with outcomes on most of the rating scales, but correlations were modest in size, possibly due to the number of different factors influencing treatment outcome

Råvaruproducenter med Varumärken

Syfte; Syftet är att studera om och hur tre råvaruproducenter i Skåne, genom att skapa förutsättningar för framtida kundrelationer som utvecklar deras varumärken, har utnyttjat kundens delaktighet i varumärkets meningsskapande. Metod; Uppsatsen består av en kvalitativ fallstudie av tre råvaruproducenter. Ansatsen är deduktiv och utgår från det ramverk av teorier som använts i genomförandet av studien. Med utgångspunkt i det insamlade materialet återknyts sedan till teorierna i uppsatsens slutsats. Teoretiskt perspektiv; Teoriavsnittet ger en fördjupad förståelse för hur man kan arbeta med varumärkesutveckling. Flera av dessa lägger vikt vid att varumärken inte har något värde i sig utan att det uppstår i relationen till kunderna. Här uppdagar sig en angränsning till studier som antagit ett konsumentperspektiv, men uppsatsen håller ett strikt producentperspektiv. Empiri; Empirin grundar sig på intervjuer av tre råvaruproducenter som har utvecklat sina varumärken. Dessa är Gunnarhögs Jordbruk AB som producerar kallpressad rapsolja från Österlen, Bjäre Hembygd som primärt odlar och säljer färskpotatis och Ingelsta Kalkon som föder upp, förädlar och säljer kalkonkött. Ingelsta är idag uppköpta av Blenta AB. I det sistnämnda fallföretaget är det grundarna, som intervjuats. Resultat; Studiens slutsats visar att råvaruproducenter, med insikt i hur varumärkens mening bildas och utvecklas, kan skapa förutsättningar som gör att de kan utveckla sina varumärken. Detta ställer krav på en djupare förståelse kring varumärkets relation till konsumenten, och att de i gemensam interaktion skapar varumärkets betydelse och värde. Vi hävdar att detta beror på förmågan att utnyttja sin lokala profil och använda sina gårdar som personliga mötesplatser. Vi har dessutom kunnat se hur dessa möten inte begränsas till gårdsplanen, utan vandrat vidare i berättelser som gjort att man har kunnat bygga långsiktiga kundrelationer. Kundernas upplevelser har adderat ett immateriellt värde till produkten och varumärket

Beyond CSR - Global Corporate Citizenship

Uppsatsen syftar till att med hjälp av de begrepp, vilka kretsar kring företagsansvar, utforska den nya typen av socialt ansvarstagande, benämnt GCC. Författarna lyfter fram tre svenska multinationella företag och undersöker hur de tar ett socialt ansvar i förhållande till GCC. Företag kan genom att tillämpa GCC, adressera makroproblem och i samband med detta generera vinst. Samarbete och driven ledare är nyckelord i dessa sammanhang

Treatment of trauma-affected refugees with venlafaxine versus sertraline combined with psychotherapy:a randomised study

BACKGROUND: The prevalence of trauma-related psychiatric disorders is high among refugees. Despite this, little is known about the effect of pharmacological treatment for this patient group. The objective of the present study was therefore to examine differences in the effects of venlafaxine and sertraline on Post-Traumatic Stress Disorder (PTSD), depression and functional impairment in trauma-affected refugees. METHODS: The study was a randomised pragmatic trial comparing venlafaxine and sertraline in combination with psychotherapy and social counselling. PTSD symptoms were measured on the Harvard Trauma Questionnaire – part IV, which was the primary outcome measure. Other outcome measures included: Hopkins Symptom Check List-25 (depression and anxiety), Social Adjustment Scale – short version (social functioning), WHO-5 Well-being Index (quality of life), Crisis Support Scale (support from social network), Sheehan Disability Scale (disability in three areas of functioning), Hamilton Depression and Anxiety scale, the somatisation items of the Symptoms Checklist-90, Global Assessment of Functioning scales and the summarised score of pain in four body areas rated on visual analogue scales. RESULTS: Two hundred seven adult refugee patients were included in the trial (98 in the venlafaxine and 109 in the sertraline group). Of these, 195 patients were eligible for intention-to-treat analyses. Small but significant pre-treatment to post-treatment differences were found on the Harvard Trauma Questionnaire and a number of other ratings in both groups. On the primary outcome measure, no difference was found in treatment effect between the sertraline and venlafaxine group. A significant group difference was found in favour of sertraline on the Sheehan Disability Scale. CONCLUSION: Sertraline had a slightly better outcome than venlafaxine on some of the secondary outcome measures, but not on the primary outcome measure. Furthermore, a higher percentage of dropouts was found in the venlafaxine group compared to the sertraline group. Although this could indicate that sertraline was better tolerated, which is supported by other studies, a final conclusion on tolerability cannot be drawn from the current study due to lack of systematic reporting of side effects. TRIAL REGISTRATION: ClinicalTrials.gov NCT01569685. Registration date: 28/2/12 ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12888-016-1081-5) contains supplementary material, which is available to authorized users

Förväntade effekter på bentisk primärproduktion och fiskbiomassa av en tröskeldamm i reglingsmagasinet Grundsjön

Reglering av sjöar för vattenkraftproduktion innebär ofta att stora delar av sjöns bottenyta torrläggs när vattenståndet är lågt, med negativa konsekvenser för sjöarnas födovävar. I Grundsjön (Härjedalen), överväger Fortum att anlägga en tröskeldamm för att förhindra torrläggningen av ett grundområde i sjön, med syfte att minska regleringens påverkan på sjöekosystemet. En stabilare miljö utan torrläggning möjliggör över tid en ackumulering av bottensediment och därmed en nyetablering av bottenlevande (bentiska) alger, insektslarver och kräftdjur vilket i sin tur sannolikt får positiva effekter på födotillgången för fisk. I denna rapport sammanfattar vi kunskapsläget gällande fisk- och primärproduktion i klarvattensjöar, och utifrån befintlig kunskap beräknar vi hur framförallt bentisk primärproduktion och fiskbiomassa förväntas påverkas av anläggandet av en tröskeldamm i Grundsjön. Vi har utgått från två alternativa tröskellägen i Grundsjön, där våra uppskattningar ger ca 20 gånger högre bentisk primärproduktion på den annars temporärt torrlagda bottenytan i det ena området, och ca 5 gånger högre i det andra området, jämfört med nuvarande situation. Samma ökning uppskattas för fiskbiomassa eftersom våra beräkningar visar att fiskbiomassa ökar proportionerligt med bentisk primärproduktion

Educational attainment and mortality in schizophrenia

Background Individuals suffering from schizophrenia have a reduced life expectancy with cardiovascular disease (CVD) as a major contributor. Low educational attainment is associated with schizophrenia, as well as with all-cause and CVD mortality. However, it is unknown to what extent low educational attainment can explain the increased mortality in individuals with schizophrenia. Aim Here, we quantify associations between educational attainment and all-cause and CVD mortality in individuals with schizophrenia, and compare them with the corresponding associations in the general population. Method All Norwegian citizens born between January 1, 1925, and December 31, 1959, were followed up from January 1, 1990, to December 31, 2014. The total sample included 1,852,113 individuals, of which 6548 were registered with schizophrenia. We estimated hazard ratios (HR) for all-cause and CVD mortality with Cox models, in addition to life years lost. Educational attainment for index persons and their parents were included in the models. Results In the general population individuals with low educational attainment had higher risk of all-cause (HR: 1.48 [95% CI: 1.47–1.49]) and CVD (HR: 1.59 [95% CI: 1.57–1.61]) mortality. In individuals with schizophrenia these estimates were substantially lower (all-cause: HR: 1.13 [95% CI: 1.05–1.21] and CVD: HR: 1.12 [95% CI: 0.98–1.27]). Low educational attainment accounted for 3.28 (3.21–3.35) life years lost in males and 2.48 (2.42–2.55) years in females in the general population, but was not significantly associated with life years lost in individuals with schizophrenia. Results were similar for parental educational attainment. Conclusions Our results indicate that while individuals with schizophrenia in general have lower educational attainment and higher mortality rates compared with the general population, the association between educational attainment and mortality is smaller in schizophrenia subjects than in the general population.publishedVersio