Massively parallel implicit equal-weights particle filter for ocean drift trajectory forecasting

Forecasting of ocean drift trajectories are important for many applications, including search and rescue operations, oil spill cleanup and iceberg risk mitigation. In an operational setting, forecasts of drift trajectories are produced based on computationally demanding forecasts of three-dimensional ocean currents. Herein, we investigate a complementary approach for shorter time scales by using the recently proposed two-stage implicit equal-weights particle filter applied to a simplified ocean model. To achieve this, we present a new algorithmic design for a data-assimilation system in which all components – including the model, model errors, and particle filter – take advantage of massively parallel compute architectures, such as graphical processing units. Faster computations can enable in-situ and ad-hoc model runs for emergency management, and larger ensembles for better uncertainty quantification. Using a challenging test case with near-realistic chaotic instabilities, we run data-assimilation experiments based on synthetic observations from drifting and moored buoys, and analyze the trajectory forecasts for the drifters. Our results show that even sparse drifter observations are sufficient to significantly improve short-term drift forecasts up to twelve hours. With equidistant moored buoys observing only 0.1% of the state space, the ensemble gives an accurate description of the true state after data assimilation followed by a high-quality probabilistic forecast

A Loudspeaker Element as a Passive or Active Resonance Absorber

Absorbing low frequent sound is a challenge, but earlier studies, (Rivet, 2017), (R. Boulandet, 2014) and (Lissek et al., 2011), have shown that a loudspeaker can function well as an absorber with a broader frequency spectre than conventional resonance absorbers. It is claimed that the mechanical properties of the loudspeaker element, which is what makes it to a resonance absorber, can be cancelled by using the right feedback in an active chain. One of the methods, described in (Lissek et al., 2011), shows remarkable results using particle velocity and pressure in an analogue feedback circuit. This method is in this thesis further investigated together with the absorption capabilities of a standard loudspeaker as a semi-active or passive absorber, which means either connected to an amplifier or not. The thesis firstly presents the theory needed to understand how a loudspeaker can function as an absorber. Further on several measurements are performed; finding the loudspeaker parameters, adjusting the impedance by connecting different resistances to the terminal of the loudspeaker element, adjusting the active system to achieve optimal absorption and finding the effective absorption area of an ordinary loudspeaker in a reverberant room. An ordinary loudspeaker was found to have high absorption around its resonance frequency. An optimal shunt resistor value could be calculated by the loudspeaker element parameters, and by connecting the optimal shunt resistor, the absorption factor was measured to 1 at the resonance frequency. It is though some loudspeaker elements with parameters so that the optimal resistor value is negative. Those are not recommended to use as active absorbers, but if the negative value is low, they will be good passive absorbers. Overall, the result shows that a traditional loudspeaker has some affection to the acoustical properties of a room. The active feedback system needs equipment where the sensitivity is not frequency dependent and the phase is unaffected for the frequency range of interest. It does also seem like the parameters of the loudspeaker element must be carefully chosen to get good results. The results achieved, by using two different loudspeaker elements, indicates that it potentially might work, but was with the given loudspeaker elements far from as good as the results achieved by a previous study (Lissek et al., 2011). Suggestions for optimal loudspeaker parameters are given

Morphological Variations of the Mandibular Premolars. Tooth Morphology and Identification - A Macro Analysis

Background: In the context of teaching tooth morphology to dentist students, which is based on the anatomical and morphological hallmarks described in the literature, some of the teeth in the permanent dentition have shown to be harder to characterize than others. The aim of this project was to specifically focus on the premolars of the lower jaw. By studying a collection of extracted teeth and dental casts, we wanted to explore why the task of differentiating and deciding premolars remain troublesome, and look for novel morphological features on the lower jaw premolars. The knowledge gained here may therefore be useful in the teaching of dental morphology in general, or even interesting in the context of anthropological and developmental biological studies. Material and methods: A total of 216 extracted mandibular premolars from University of Oslo and University of Tromsø – The Arctic University of Norway were selected and studied for quality, and then separated into three groups by four evaluators as: “typical 1st premolars”, “typical 2nd premolars” and “atypical premolars”. The teeth were then organized in subgroups and photographed from different dental aspects. In addition, 30 dental casts contributed from the Public Dental Service Competence Center of Northern Norway were measured and photographed. Studying and analyzing the extracted teeth and dental casts led to a proposal of eleven different hypotheses. These hypotheses were then used one at a time to categorize the “atypical premolars” as a 1st or a 2nd premolar, by three independent evaluators. Significant agreements among the evaluators were then used as a measurement for “strong”, “medium” or “weak” morphological features. Results and conclusion: Out of the eleven proposed hypotheses, we report four novel features from this study. The first feature states that when observed from an approximal aspect “the marginal ridge line ends centrally on the 2nd premolars, but it continues further towards the lingual aspect on the 1st premolars”. The second feature indicates that when observed from an occlusal angle, “the pits making up the central fissure will align on a centrally straight line placed (mesio-distal axis) in the 2nd premolars, but not in the 1st premolars”. The third feature describes a significant difference in the width/height-ratio of the two lower premolars when observed from a facial aspect. The fourth feature demonstrates that the observable facial aspect, when observed from an occlusal aspect, differs between the premolars

Development of a light, strong and mobile solution to accommodate elevated backrest in extreme conditions on a Franco Garda stretcher

Etter å ha etablert kontakt med Norsk Luftambulanse (NAA), ble et prosjekt presentert som en potensiell masteroppgave. Prosjektet innebar å utvikle en ny fikstur for en av deres medisinske redningsbårer. Nærmere bestemt Franco Garda-båren. (FG-båren). Dette er en lettvektig, solid, franskbygget båre ment for redningsoperasjoner i utfordrende terreng. Båren kan dras på alle underlag, og kan brukes i underhengende oppdrag fra helikopter. En funksjon den mangler derimot er muligheten for å heve pasienten til hevet ryggleie. Dette har vært utfordringen for dette prosjektet. Double Diamond-modellen har vært fremtredende gjennom hele prosjektet. Benchmarking ved å kombinere behov og beregninger har blitt brukt for å evaluere og sammenligne konseptene. Å heve pasienten til hevet ryggleie kan i mange tilfeller være livsviktig for pasienten. Det er også ofte en mer behagelig stilling for pasienten. Det er imidlertid ingen medisinske redningsbårer som er så allsidige som FG-båren, og samtidig har har mulighet til å heve pasienter til hevet ryggleie. NAA har 13 helikopterbaser spredt over Norge. Alle basene deres er utstyrt med to typer bårer. Aerolite Cirrus-båren (AC-båren), som for de fleste baser er primærbåren, og FG-båren. FG-båren brukes hovedsakelig til søk og redningsoppdrag på grunn av dens høye funksjonalitet i ulike terreng. Brukerinnsikt i starten av prosjektet la grunnlaget for kravspesifikasjoner som senere ble brukt til å vurder og sammenligne konsepter. Prosjektets første fokus var å finne løftemekanismen som var best egnet for å oppfylle kravene. Prototyper ble laget for å validere funksjonalitet og anslå konseptenes potensial. Konseptene ble nøye utvalgt ved hjelp av ambulansepersonell fra både Norge og Sveits. Vektberegninger vurdert sammen med hvordan mekanismen betjenes, og hvordan man fester den til båren, ble også tatt i betraktning før et endelig konsept ble valgt. Det valgte konseptet for løftemekanismen er en blokkerbar gassfjær. Detaljering av konseptet krevde nøyaktige beregninger av ideelle vinkler og lengder for å finne den optimale gassfjæren. Etter at konseptet for løftemekanismen ble valgt startet en ny idéfase. Å finne den beste måten å feste gassfjæren til båren viste seg å være enda en omfattende produktutviklingsprosess. Lite plass, strenge krav og flere runder med analyser er nøkkelord for denne prosessen. Flere iterasjoner senere presenteres to løsninger gjennom denne rapporten. De to løsningene er like bortsett fra måten de er festet til den originale båren. Den første løsningen fester en avstiver permanent under de eksisterende brakettene, og bruker en hurtigutløsermekanisme for å koble resten av fiksturen til avstiveren. Den andre løsningen har ingen permanente deler og festes direkte på de eksisterende brakettene ved hjelp av en fjærbelastet låsemekanisme.After establishing contact with the Norwegian Air Ambulance (NAA), a project was presented as a potential master thesis. The project involved developing a new fixture for one of their medical rescue stretchers. More specifically the Franco Garda stretcher. (FG-stretcher). A lightweight and tough french-built stretcher meant for rescue operations in challenging terrain. The stretcher can be dragged on any surface and can be hoisted from a helicopter. One thing it can’t do is to raise the patient to elevated backrest. That has been the challenge for this project. The Double Diamond model has been prominent through the whole project. Benchmarking by combining needs and metrics has been used to evaluate and compare the concepts. Raising the patient to elevated backrest can in many cases be vital for the patient. It is also a more comfortable position for the patient. However, there are no medical rescue stretchers that are as versatile as the FG-stretcher while still having the ability to raise patients to elevated backrest. The NAA has 13 helicopter bases spread over Norway. All of their bases are equipped with two types of stretchers. The Aerolite Cirrus stretcher (AC-stretcher), which for most bases is the primary stretcher, and the FG-stretcher. The FG- stretcher is used mainly for search and rescue missions, because of it’s high functionality in various terrain. User insights in the beginning of the project laid a foundation of requirement specifications which later has been used to compare and evaluate concepts. The first focus of the project was to find the mechanism that was best suited to meet the requirements. Prototypes were made to validate functionality and potential of the concepts. The concepts were carefully selected with the help of paramedics from both Norway and Switzerland. Weight estimations along with how the mechanism is operated, and how to secure it to the stretcher were also taken into concideration before setteling on a final concept. The chosen concept for the lifting mechanism is a blockable gas spring. Detailing the concept required precise calculations of ideal angles and lengths to find the optimal gas spring. After the concept for the lifting mechanism was chosen, a new ideation phase began. Finding the best way to attach the gas spring to the stretcher turned out to be another comprehensive product development process. Little space, strict requirements and several analysises are key words to this process. Several iterations later, two solutions are being presented through this report. The two solutions are similar except from the way they are fastened to the original stretcher. The first solution attaches a brace permanently beneath the excisting brackets and uses a quick release mechanism to connect the fixture to the brace. The second solution is more easily removable and is fastened directly onto the excisting brackets using a spring loaded latching mechanism

Simulating the Euler equations on multiple GPUs using Python

GPUs have become a household name in High Performance Computing (HPC) systems over the last 15 years. However, programming GPUs is still largely a manual and arduous task, which requires expert knowledge of the physics, mathematics, and computer science involved. Even though there have been large advances in automatic parallelization and GPU execution of serial code, it is still difficult to fully utilize the GPU hardware with such approaches. Many core numeric GPU codes are therefore still mostly written using low level C/C++ or Fortran for the host code. Several studies have shown that using higher level languages, such as Python, can make software development faster and with fewer bugs. We have developed a simulator based on PyCUDA and mpi4py in Python for solving the Euler equations on Cartesian grids. Our framework utilizes the GPU, and can automatically run on clusters using MPI as well as on shared-memory systems. Our framework allows the programmer to implement low-level details in CUDA C/C++, which is important to achieve peak performance, whilst still benefiting from the productivity of Python. We show that our framework achieves good weak and strong scaling. Our weak scaling achieves more than 94% efficiency on a shared-memory GPU system and more than 90% efficiency on a distributed-memory GPU system, and our strong scaling is close to perfect on both shared-memory and distributed-memory GPU systems.publishedVersio

Barns opplevelse av ventetid i barnehagen

Hvordan påvirker voksenpålagt venting i påkledningssituasjoner barns opplevelse av overgangssituasjoner i barnehagen, og hvordan oppleves ventetid for barn?publishedVersio

Vulvodyni og hypnoterapi - I hvilken grad kan hypnose vise seg effektiv i behandlingen av smerter hos kvinner med vulvodyni?

Sammendrag Bakgrunn: Vulvodyni er en samlebetegnelse på smertetilstander lokalisert i deler av kvinnens ytre kjønnsorgan, og rammer mellom 3 og 15% av kvinner i alle aldere. Det finnes ulike behandlingsformer, men ingen med signifikante effekter på tilstanden. Hensikt: Studiens hensikt er å utforske om hypnoterapi kan være en effektiv behandling av vulvodyni. Problemstilling: I hvilken grad kan hypnose vise seg effektiv i behandlingen av smerter hos kvinner med vulvodyni? Metode: Litteraturstudie med systematisk tilnærming. Systematisk litteratursøk utført via databaseverten Ovid i EMBASE, MEDLINE og APA PsycInfo januar 2023. Funnene ble overført til EndNote og analysert. Studiekvaliteten ble vurdert etter Grading of Recommendations Assessment, Development and Evaluation (GRADE). Resultat: Fire artikler ble inkludert. Det var totalt 73 kvinner som mottok hypnoterapi som behandling for vulvodyni. Det var tre felles hovedfunn fra artiklene; Svak forskningsbasert evidens for at hypnoterapi har effekt på vulvodyni, potensiell positiv effekt av hypnoterapi på vulvodyni, og behov for videre forskning. Konklusjon: Det er utført få studier på hypnoterapi som behandling av vulvodyni. Studiene inkludert i denne oppgaven ble vurdert til svært lav vitenskapelig kvalitet, noe som innebærer at de ikke ga grunnlag for bevis eller evidens for at hypnoterapi faktisk har effekt på vulvodyni. Tross svak evidens er det mulig at hypnoterapi kan være en lovende terapiform for vulvodyni. Men det er behov for ytterligere forskning, med et studiedesign, som for eksempel mixed methods design, som vil kunne forske på hele mennesket ut ifra et biopsykososialt perspektiv. Nøkkelord: Vulvodyni, hypnoterapi, biopsykososialt perspektiv, kronisk smertelidelse, kvinnehels

Trykkbølgebehandling ved akillestendinopati

Bakgrunn: Akillestendinopati er en utbredt og ofte langvarig diagnose som ofte sees i idretter med mye løping. I klinikken praktiseres ulike behandlingsmetoder for tilstanden. I nyere tid har trykkbølgebehandling blitt en stadig mer utbredt behandlingsmetode. Formålet med denne studien er å se på effekten av trykkbølgebehandling på smerteintensitet og funksjon ved akillestendinopati i hvile. Design: Litteraturstudie Hensikt: Undersøke effekten av trykkbølgebehandling ved akillestendinopati Metode: Studier ble identifisert gjennom systematisk søk i databasene AMED, EMBASE, MEDLINE og PsycINFO, samt gjennom referanselistene til de inkluderte studiene. Totalt syv kvantitative studier ble inkludert. Resultat: Antall inkluderte studier, samt studienes omfang og heterogenitet gjør at det ikke kan trekkes entydige konklusjoner. Trykkbølgebehandling ser ut til å ha en positiv effekt på smerte og funksjon ved akillestendinopati. Konklusjon: Resultatene fra studiene kan tyde på at trykkbølgebehandling har en positiv effekt ved akillestendinopati. For å bedre besvare problemstillingen vil det være behov for flere, og gjerne nyere studier med større grad av homogenitet der effekten av trykkbølgebehandling undersøkes isolert.Background: Achilles tendinopathy is a widespread and often long-term diagnosis that is often seen in sports which requires running. In the clinic various treatment methods are used for the condition. In recent times, shock wave therapy has become an increasingly widespread treatment method. The purpose of this study is to examine the effect of shock wave treatment on pain intensity and function on Achilles tendinopathy at rest. Design: Litterature study Aim: Examine the effect of shock wave treatment on Achilles tendonopathy Method: Studies were identified through systematic searches in the AMED, EMBASE, MEDLINE and PsycINFO databases, as well as through the reference lists of the included studies. A total of seven quantitative studies were included. Results: The number of studies included, as well as the scope and heterogeneity of the studies, makes it impossible to draw unambiguous conclusions. Shock wave treatment appears to have a positive effect on pain and function in Achilles tendonopathy. Conclusion: The results of the studies may indicate that shock wave treatment has a positive effect on Achilles tendonopathy. In order to better answer the issue, there will be a need for more, and preferably more recent studies with a greater degree of homogeneity where the effect of shock wave treatment is investigated isolated

Proteinase-activated receptor-2: two potential inflammatory mediators of the gastrointestinal tract in Atlantic salmon

Proteinase-activated receptor 2 (PAR-2), activated by trypsin and other serine proteinases, is a key initiator of inflammatory responses in the intestine of mammals. Atlantic salmon fed diets with standard qualities of soybean meal (SBM) show enteritis of the distal intestine as well as increased activity of trypsin in both luminal contents and wall tissue. Luminal trypsin activity may possibly be involved in immune related disorders of the intestine also in Atlantic salmon via activation of PAR 2. In the present study our aim was to investigate if PAR-2 play a role in SBM induced enteritis. We performed multiple alignments based on nucleic acid sequences of PAR-2 from various animals available from public databases, and designed primers for use in cloning of the Atlantic salmon PAR-2 transcript. We further cloned and characterized the full length sequence of Atlantic salmon PAR-2 and investigated the expression in both early and chronic stages of SBM induced enteropathy. Two full length versions of PAR-2 cDNA were identified and termed PAR-2a and PAR-2b. Expression of the two PAR-2 transcripts was detected in all 18 tissues examined, but most extensively in the intestine and gills. A significant up-regulation in the distal intestine was observed for the PAR-2a transcript after 1 day feeding diets containing SBM. After 3 weeks of feeding, PAR-2a was down-regulated compared to the fish fed control diets. These findings may indicate that PAR-2a participates in inflammatory responses in both the early and later stages of the SBM enteropathy. In the chronic stages of the enteropathy, down-regulation of PAR-2a may indicate a possible desensitization of the PAR-2a receptor. Expression of PAR-2b was not altered in the first 7 days of SBM feeding, but a significant up regulation was observed after 3 weeks, suggesting a putative role in chronic stages of SBM induced enteritis. The expression differences of the two PAR-2 transcripts in the feed trials may indicate that they have different roles in the SBM induced enteritis