Continuous Max-Flow for Image Segmentation with Shape Priors

In this thesis we propose a stable method for image segmentation with shape priors. The original Chan-Vese intensity based segmentation model with regularisation term is extended to include shape prior information. We study shape priors which are pose invariant under the group of similarity transformations, that is under rotation, scaling and translation. In order to solve this problem robustly and effectively, an algorithm based on the theory of max-flow and min-cut is used in addition to a gradient descent procedure for updating the pose parameters. Comprehensive experiments are provided to demonstrate the behaviour of the proposed method on different images.Master i Anvendt og beregningsorientert matematikkMAMN-MABMAB39

Gardening as a Meaningful Occupation in Initial Stroke Rehabilitation: An Occupational Therapist Perspective

Background: Initial rehabilitation after stroke is demanding for patients whose primary aim is to regain their functions. The literature indicates that gardening may provide medical rehabilitation opportunities and health resources. This study explored occupational therapists’ own observations and descriptions on how participation in a gardening group may support inpatients’ initial rehabilitation following acute stroke. Methods: The authors analyzed notes written by occupational therapists during a 6 month-period that reflected their observations and descriptions after sessions with a gardening group. The therapists were trained in stroke rehabilitation and offered two sessions with gardening groups per week. The sessions were integrated into the occupational therapy program at a residential rehabilitation hospital. The study had a qualitative descriptive design, which included thematic analysis. Results: Six themes were revealed: possibilities for skills training, engagement in the occupation, mastery of the activity, finding mental rest, connection to past experiences, and shared experiences and hope. Conclusions: The occupational therapists found that gardening provided clinical opportunities for skills training and health resources. The results are discussed in relation to meaningful occupations through occupational characteristics, such as doing, being, becoming, and belonging. As a group-based, common occupation, gardening may provide a complementary approach in stroke rehabilitation

Spatiotemporal humidity variation in student housing

Modern, urban apartments are space-efficient, have bathrooms with no windows, and require energy-efficient ventilation with heat recovery. The requirements for exhaust ventilation rates for the kitchen and bathrooms are independent of dwelling size. In some countries, it is required that the extract air can be increased on demand. There is a need for more knowledge on the effects of these requirements on the resulting moisture level in apartments, and whether these recommendations should be modified. Measurements were done in eight student apartments. Temperature and humidity were measured with 1-minute time resolution at 5 locations in each of the apartments. Median moisture excess was 0.9-1.4 g/m³, indicating a small risk of interstitial condensation. 90th percentiles of relative humidity were 30-35 %, indicating an elevated risk of eye and airway symptoms due to low humidity. The moisture excess was lower in apartments with heat-recovery ventilation than mechanical extract ventilation. The median moisture excess was higher in the living rooms than in bathrooms, indicating that moisture from showering and personal hygiene had little impact on the overall indoor moisture conditions in the dwellings. The average number of showers per day per apartment varied between 0.6 and 3.1. High peak moisture excess values up to 20 g/m³ were recorded in bathrooms, but for brief periods only. Consistently higher moisture peaks in extract vents than in bathroom air demonstrated that ventilation extract above the shower is effective in removing moist air from showering. Calculated moisture load in the extract air from a single shower was estimated to be 0.86 kg. Outdoor temperatures were negatively correlated with moisture excess, as predicted by EN -ISO 13788.publishedVersio

Om å gjenerobre helse : Hva fremmer og hemmer hvile for mennesker som er rammet av hjerneslag

Problemstilling: Hvordan beskriver mennesker som er rammet av hjerneslag situasjoner/kilder som fremmer hvile og situasjoner som fører til ikke-hvile, med hovedfokus på hvileperspektivet? Formål: Formålet er å beskrive og forstå mennesker med hjerneslag sine egne erfaringer med situasjoner eller kilder som fremmer hvile. Jeg har også ønsket å se hvordan intervjupersonene beskriver situasjoner som skaper ”en tilstand av ikke-hvile”. Det er nyttig å vite noe om dette for å kunne avskjerme fra noe av det som skaper ikke-hvile og hjelpe slagpasienten til å leve et liv i balanse mellom det som gir og tar krefter. Metode: Jeg velger å bruke et fenomenologisk design. For å få svar på mine forskningsspørsmål, ønsker jeg å bruke det kvalitative forskingsintervjuet som metode. Åtte personer med hjerneslag har bidratt i studien. Mitt materiale vil være overveiende empiristyrt. Litteratur og teoretisk forankring: For å forstå den samfunnsmessige kontekst intervjupersonene lever i, har jeg benyttet meg av populærvitenskapelig litteratur som beskriver samfunnsendringer de siste tiår og hva som preger den tiden vi lever i her i Vesten. For bedre å forstå hva som fremmer eller hemmer hvile hos mennesker med hjerneslag har jeg valgt å plassere meg innenfor en fenomenologisk teoriramme. Resultater/konklusjon: Undersøkelsen viser at mange personer med hjerneslag strever med sin identitet. Situasjoner der personen blir anerkjent for den han/hun er, har en mulighet i seg for at den enkelte kan kjenne hvile. Det motsatte, hvis personen ikke blir sett og anerkjent for den de er, vil dette lett føre dem inn i ”en tilstand av ikke-hvile”. Mange vektlegger betydningen av det gode, støttende fellesskapet. Tid og rom til refleksjon er viktig, dette kan skape ytterligere hvile. Ny mening til livet for de som finner den, kan gi ny livsgnist og nye krefter. Passelig mengde utfordringer i forhold til de ressurser man er i besittelse av, er også brakt på banen. Å være mer vár livsrytmen i livet, er også kommet fram i intervjuene, for eksempel det å ikke ta med seg jobben hjem og det å ta seg fri i helgene. Hvis intervjupersonene ikke tar hensyn til dette blir de lett ført inn i ”en tilstand av ikke-hvile”. Det å lære seg ”å leve i nuet” er også et tema som er kommet fram i studien, likedan betydningen av takknemlighet og frihet fra bekymring og tvang. Dette er med å fremme hvile. Flere av intervjupersonene nevner natur, det å komme avsides, og kunstens mange utrykk som kilder til hvile. Musikklytting har fått et ekstra fokus. Det var mange som brakte det på banen. Intervjupersonene ser på musikklyttingen som en god kilde til å finne hvile. Flere av intervjupersonene er opptatt av å ha en åndelig dimensjon i livet. De som uttaler seg om dette emnet, gir utrykk for at dette gir en indre ro. Ved å lytte til den enkelte pasient med hjerneslag om hva hvile betyr i deres liv, vil helsepersonell kunne få en forståelse for hva som skaper hvile. Det at helsepersonell får innsikt i dette, kan få implikasjoner for terapeutisk praksis. Dette kan bety at pasienter med hjerneslag får en bedret helse. I denne studien vektlegges viktigheten av at det blant annet legges til rette for rolige, harmoniske omgivelser, tilgang til natur og kultur og et anerkjennende miljø. Det bør også gis mulighet for at pasienten kan ta opp eksistensielle spørsmål. Det er viktig med en fokusering som rommer hele personen og dens omverden, slik at den som er rammet av sykdom, kan hjelpes fram i mot en mer hjemlig væren-i-verden (Svenaeus 2005)

Effect of Continuous Positive Airway Pressure on Symptoms and Prevalence of Insomnia in Patients With Obstructive Sleep Apnea: A Longitudinal Study

Objective: Obstructive sleep apnea (OSA) and insomnia are the two most common sleep disorders. Continuous positive airway pressure (CPAP) is considered first-line treatment for OSA. In the present study, we assess the effect of CPAP on symptoms and prevalence of insomnia in patients with OSA. We hypothesized a decrease in insomnia symptoms from CPAP initiation to follow-up, and that this decrease would depend on CPAP adherence. Materials and methods: The sample included 442 patients diagnosed with OSA [mean age 54.9 years (SD = 12.1), 74.4% males] who started treatment with CPAP at a university hospital. OSA was diagnosed according to standard respiratory polygraphy. Mean apnea-hypopnea index (AHI) was 30.1 (SD = 21.1) at baseline. Insomnia was assessed prior to CPAP treatment (baseline) and at follow-up after a median of 19.9 weeks (range 6–52 weeks) with the Bergen Insomnia Scale (BIS). CPAP adherence was defined as an average use of ≥ 4 h per night, whereas non-adherence was defined as < 4 h per night. Results: There was a significant decrease in BIS scores from baseline (mean = 18.8, SD = 9.8) to follow-up (mean = 12.9, SD = 9.9), p < 0.001. Cohen’s d(0.65) indicated a moderate effect size. The reduction in BIS scores was depending on CPAP adherence (interaction effect F(1,440) = 12.4, p < 0.001), with larger reduction in the adherent group than in the non-adherent group. The proportion of patients with chronic insomnia was significantly reduced from 51.1% at baseline to 33.0% at follow-up (p < 0.001). Conclusion: Overall, there was a significant reduction in insomnia symptoms from baseline to follow-up. The improvement was significant in both adherence groups, but the degree of improvement was larger among patients who were adherent to CPAP. Furthermore, there was a significant reduction in the prevalence of chronic insomnia at follow-up compared to baseline. This suggests that CPAP effectively reduces both the presence of insomnia and the severity of insomnia symptoms in some patients with OSA.publishedVersio

The effects of goal commitment and social integration on college drop-out

© 2019 Author(s). This is an open access article distributed under the terms of the Creative Commons CC-BY 4.0 License (https://creativecommons.org/licenses/by/4.0/)Formålet med denne studien er å kartlegge hvordan utvalgte faktorer påvirker sannsynligheten for å falle fra sitt første påbegynte studieløp i høyere norsk utdanning. Vi fokuserer spesielt på hvilke effekter (1) ulike former for sosial integrasjon/tilhørighet og (2) studentenes evne til å sette seg mål og forplikte seg til å nå dem, har på sannsynligheten for å falle fra. Vi kontrollerer også for andre forhold som har vist seg viktig i tidligere forskning på frafall i høyere utdanning. Analysene er gjennomført på data samlet inn via en spørreundersøkelse blant tidligere studenter ved Høgskolen i Lillehammer (nå en del av Høgskolen i Innlandet) våren 2016. Resultatene viser liten eller ingen effekt de ulike formene for sosial integrasjon mellom studenter, men at god sosial integrasjon med faglig ansatte ved høgskolen kan medføre lavere sannsynlighet for å falle fra. Vi finner også en sterk effekt fra variabelen som ser på studentenes evner til å sette seg mål, og forplikte seg til å nå dem, på frafallet. I tillegg viser resultatene at mange av funnene fra tidligere norsk og internasjonal forskning støttes i vår studie.ABSTRACT: The objective of this paper is to examine how various factors affect the probability of students dropping out from higher education before completing a degree. We focus particularly on what effects (1) various forms of social integration, and (2) the student’s ability to set– and commit to goals, have on the probability of students dropping out. We also control for other variables from previous research. The analyses are carried out on data obtained from a survey among former students at Lillehammer University College (now Inland Norway University of Applied Sciences) during the spring of 2016. Our results show little, or no, effect from the various measures of social integration among the students, but that a good social integration with faculty induces a lower probability of dropping out. We also find a strong effect from the variable which measures the student’s abilities to set and commit to goals on the probability of dropping out. Additionally, we find support for much of the findings from previous Norwegian and international research in this study.publishedVersio

Source-lens clustering effects on the skewness of the lensing convergence

The correlation between source galaxies and lensing potentials causes a systematic effect on measurements of cosmic shear statistics, known as the source-lens clustering (SLC) effect. The SLC effect on the skewness of lensing convergence, $S_3$, is examined using a nonlinear semi-analytic approach and is checked against numerical simulations. The semi-analytic calculations have been performed in a wide variety of generic models for the redshift distribution of source galaxies and power-law models for the bias parameter between the galaxy and dark matter distributions. The semi-analytic predictions are tested successfully against numerical simulations. We find the relative amplitude of the SLC effect on $S_3$ to be of the order of five to forty per cent. It depends significantly on the redshift distribution of sources and on the way the bias parameter evolves. We discuss possible measurement strategies to minimize the SLC effects.Comment: 14 pages, 14 figures, accepted for publication in MNRA

A Monte Carlo comparison between template-based and Wiener-filter CMB dipole estimators

We review and compare two different CMB dipole estimators discussed in the literature, and assess their performances through Monte Carlo simulations. The first method amounts to simple template regression with partial sky data, while the second method is an optimal Wiener filter (or Gibbs sampling) implementation. The main difference between the two methods is that the latter approach takes into account correlations with higher-order CMB temperature fluctuations that arise from non-orthogonal spherical harmonics on an incomplete sky, which for recent CMB data sets (such as Planck) is the dominant source of uncertainty. For an accepted sky fraction of 81% and an angular CMB power spectrum corresponding to the best-fit Planck 2018 $\Lambda$CDM model, we find that the uncertainty on the recovered dipole amplitude is about six times smaller for the Wiener filter approach than for the template approach, corresponding to 0.5 and 3$~\mu$K, respectively. Similar relative differences are found for the corresponding directional parameters and other sky fractions. We note that the Wiener filter algorithm is generally applicable to any dipole estimation problem on an incomplete sky, as long as a statistical and computationally tractable model is available for the unmasked higher-order fluctuations. The methodology described in this paper forms the numerical basis for the most recent determination of the CMB solar dipole from Planck, as summarized by arXiv:2007.04997.Comment: 8 pages, 10 figures, submitted to A&

Interrater agreement on classification of photoparoxysmal electroencephalographic response

Our goal was to assess the interrater agreement (IRA) of photoparoxysmal response (PPR) using the classification proposed by a task force of the International League Against Epilepsy (ILAE), and a simplified classification system proposed by our group. In addition, we evaluated IRA of epileptiform discharges (EDs) and the diagnostic significance of the electroencephalographic (EEG) abnormalities. We used EEG recordings from the European Reference Network (EpiCARE) and Standardized Computer-based Organized Reporting of EEG (SCORE). Six raters independently scored EEG recordings from 30 patients. We calculated the agreement coefficient (AC) for each feature. IRA of PPR using the classification proposed by the ILAE task force was only fair (AC = 0.38). This improved to a moderate agreement by using the simplified classification (AC = 0.56; P = .004). IRA of EDs was almost perfect (AC = 0.98), and IRA of scoring the diagnostic significance was moderate (AC = 0.51). Our results suggest that the simplified classification of the PPR is suitable for implementation in clinical practice