Physics Guided Machine Learning: Injecting neural networks with simplified theories

Eksponentiell vekst i datakraft og tilgjengelighet av store datasett har popularisert og forbedret maskinlæring betydelig de siste årene. Nevrale nettverk er sterke verktøy som kan oppdage mønstre i komplekse datasett og muligens modellere realistiske dynamiske systemer. Denne oppgaven undersøker et "physics-guided machine learning" rammeverk for nevrale nettverk ved å kombinere tradisjonell matematisk modellering med maskinlæringsmetoder. Her injiseres nevrale nettverk med forenklede teorier om dynamiske systemer for å forbedre nøyaktigheten og tolkningen. For å validere rammeverket gjennomgår det flere eksperimenter på forskjellige systemer som Lotka-Volterra-ligningene, Duffing-oscillatoren, Lorenz-systemet, Hindmarsh-Rose modellen og WillamowskiRössler modellen. Resultatene indikerer at det foreslåtte rammeverket kan forbedre nevrale nettverk og brukes i forskjellige vitenskapelige maskinlæringsapplikasjoner, spesielt i systemer der en forenklet modell kan hjelpe læringsprosessen.Exponential growth in computing power and availability of large datasets has popularized and progressed machine learning substantially in recent years. Neural networks are potent approximators capable of discovering patterns in complex datasets and possibly model realistic dynamical systems. This thesis investigates a physics-guided machine learning framework of neural networks that combines traditional mathematical modeling with machine learning methods. Here, neural networks are injected with simplified theories of dynamical systems at intermediate layers to improve their accuracy and interpretability. To validate the framework, it undergoes several experiments on various systems such as the Lotka-Volterra equations, Duffin oscillator, Lorenz system, Hindmarsh–Rose model, and Willamowski-Rössler model. The results indicate that the proposed framework can enhance the neural networks and be used in various scientific machine learning applications, particularly in systems where simplified theories can guide the learning process

Model Testing of the Drainage Screen Type Debris Flow Breaker

Debris flows are a hazardous geological phenomenon occurring in mountainous terrain. In Norway the National Public Roads Administration has registered around 1060 debris flows since the 1970's. The damages caused by a debris flow can be severe and sometimes tragic. Countermeasures are therefore used to protect communities, infrastructure and agriculture from its large destructive powers. Drainage screen type debris flow breakers are a countermeasure developed in Japan, but is not commonly used as local residents tend to be distrustful of its design. Japanese researchers named it debris flow breakers and it is designed as a drainage screen placed horizontally over the river bed where its purpose is to drain out the water from the debris flow that flows over. By removing the water the excess pore pressure along the shear surface is dissipated which then causes the debris flow to stop. In this thesis the drainage screen type debris flow breakers are referred to as debris flow breakers. This countermeasure is not mentioned in the NPRA's guidelines for debris flows and debris flow countermeasures, and there are only Japanese studies on the effectiveness and design of the debris flow breakers. To investigate the effectiveness of these debris flow breakers, 27 tests were carried out in a physical debris flow model. First, three reference tests with no countermeasures were done. Then, 6 tests with two solid plates were conducted to investigate the effect of placing the breakers horizontally out of the channel instead of integrating them into the channel. Finally, 18 tests were done with 6 different drainage screen breakers with the lengths 0.5 and 1.0 m and 2, 4 and 6 mm opening widths. Their effectiveness was evaluated in terms of reduced runout compared to the reference tests. The interaction between the debris flow and debris flow breaker appeared to be as the theory suggested. Water drained through and the debris flow front or body stopped on top of the breaker, depending on the length of the breaker. As a result of the stopped debris flow masses, the following part of the debris flow stopped as it flowed into the front. This damming effect caused the debris flow masses to accumulate upstream while the water drained through the masses and breakers. This upstream deposition height increased as the opening width of the debris flow breakers decreased. This was due to the amount of material that could pass through the different opening widths, the smaller opening the less material could pass and therefore accumulated upstream. The results showed that the most effective debris flow breaker was 1.0 m long and had 2 mm opening widths. This breaker had a 76% effectiveness. All the 1.0 m long breakers had an effectiveness between 73-76% and were more effective than the 0.5 m long breakers whose effectiveness was between 23-41%, where the breaker with 2 mm opening widths was the most effective. The 1.0 m long breakers were also more effective than all the other countermeasures tested in the same model before. These countermeasures included a check dam, slit dams and baffles. In conclusion, the results from the physical modeling of the debris flow breakers indicate that they are an effective countermeasure that can be trusted and could be used

Phase-type inference on competing risks models with covariates, using MCMC methods

The aim with this Master's thesis has been to develop a method of fitting a Phase-type model to a competing risks data set with covariates, and to approximate an underlying model such that important functionals and quantities can be estimated. To do this, the method proposed by Bladt et al. of fitting a Phase-type model to survival data, has been generalized to the competing risks setting, and this generalized method has been further extended to include covariates.The part of the theory which involves extending the method by Bladt et al. to competing risks was mainly produced in the Master's project in the fall of 2014, and is presented in the theory part. The method is a MCMC algorithm which updates the Phase-type parameters in a Gibbs-sampler.The results for the model without covariates show that the model is able to produce estimates for the sub-distribution functions, sub-density functions and cause-specific hazard rates in a satisfying way.Before developing the new method in the theory part, three existing competing risks regression models have been presented. This is the Fine \& Gray model, Cox regression and the model developed by Scheike and Zhang. These three models have also been used for comparison with the Phase-type model in the presentation of the results.New theory has been developed in the sense that covariates have been introduced in the existing model. This has been done by using covariate regression in the absorbing intensities of the Phase-type model.The results show that the model is suitable for a variety of different data sets and underlying distributions. The method manages to produce good estimates for the sub-distribution functions, sub-density functions, the covariate regression coefficients, and in many cases also for the cause-specific hazard rates. The estimates of the covariate regression coefficients are similar to the Cox regression coefficients

Hvordan lage papirtråd

NO: Teksten er en poetisk og praktisk inngang i hvordan lage papirtråd, kami-ito. ENG: This text is a poetic and practical introduction to how to make paper thread, kami-ito

What measures can nurses implement to prevent malnutrition among an elderly home living patient with Alzheimer`s disease?

Ved hjelp av å drøfte forsking, litteratur og eigne erfaringar, har eg kome fram til tiltak som sjukepleiarar kan sette i verk for å førebyggje underernæring hjå ein eldre heimebuande pasient med Alzheimers sjukdom (AD). sjukepleiarar kan førebyggje underernæring ved å identifisere pasienten sine utfordringar på eit tidlig tidspunkt. Kartleggingsverktøyet MNA (Mini Nutritional Assessment) kan gjerne nyttast, det er validert og anbefalt for pasientgruppa eg har fokusert på. For å sikre pasienten sitt matinntak, eller for å oppretthalde appetitten, bør sjukepleiarar ha meir fokus på måltidssituasjopnen hjå kvar enkelt pasient. Godt samarbeid mellom pårørande og heimesjukepleien kan sikre betre oppfølging av pasienten sin ernæringsstatus. Ernæringssupplement kan vere ein god måte å sikre pasienten nok næringstett kost på

Organisasjonskultur i en krisetid

Masteroppgave - Norges idrettshøgskole, 2018Oppgaven har studert organisasjonskulturen i sentraladministrasjonen til NIF gjennom å undersøke hvilke verdier, normer og holdninger som eksisterer i administrasjonen. Oppgavens hensikt er å belyse hvordan utenforstående aktører påvirker kulturen i sentraladministrasjonen, hvor blant annet mediepresset de to siste årene ble inkludert som en viktig faktor til ansattes opplevelse av kulturen på det nåværende tidspunktet. Temaet ble forsket på ved hjelp av hovedproblemstillingen: Hvordan opplever NIF-ansatte kulturen i egen organisasjon? Oppgaven ble gjennomført som en kvalitativ casestudie hvor ti semi-strukturerte intervjuer utgjør datamaterialet. Institusjonell teori ble benyttet for å belyse dataene, samtidig som elementer av kultur ble inkludert. Benyttede hovedelementer er legitimitet, ytre press, institusjonell ledelse, identitet og image. Intervjuene illustrerte mangel på institusjonell ledelse ved å vise til manglende dype felles forståelser av verdier, visjon, normer, struktur og mål. Mangelen på institusjonell ledelse har skapt usikkerhet for enkelte ansatte siden det ikke har vært tydelig hva som skal styre administrasjonen. Ansatte har dermed funnet sin egen forståelse, og arbeidet ut fra denne. De som har arbeider med samme tema har i noen tilfeller hatt samtaler rundt noen temaer, som igjen kan ha ført litt visse likheter mellom ansatte. Utenforstående aktører som særforbund, idrettskretser og KUD har også opplevd mangelen på institusjonell ledelse, og utydeligheten som har oppstått har påvirket forventninger sentraladministrasjonen opplever fra de gjeldende aktørene. Med tydelighet kunne mye av usikkerheten som hersker rundt NIF og sentraladministrasjonens arbeid blitt avklart, og imaget og legitimiteten til sentraladministrasjonen kunne vært bedre enn det er i dag.Seksjon for kultur og samfunn / Department of Cultural and Social Studie

Proactive versus standard support of labour in nulliparous women; study protocol for a randomized, controlled trial

Background Prolonged latent phase of labour often results in a traumatic birth experience. Prolonged labour is associated with more operative deliveries, haemorrhage, fetal asphyxia and poor birth experience. Women with prolonged labour in a former pregnancy more often demand caesarean section in the next, due to their negative birth experience. “Proactive support of labour” is an alternative method, developed to counteract prolonged labour. There are little research and no randomized controlled study that compare proactive to standard labour support. Methods/Design A prospective, non-blinded, randomized, single-centre, clinical trial where we compare proactive support to standard support of labour in a university hospital setting. Inclusion criteria: latent phase of labour, non-pathologic pregnancy. Robson group 1, with painful contractions, and fully effaced cervix, with 1–3 cm dilatation. Exclusion criteria: induction of labour, breech presentation, twin pregnancy, multi-parity, conditions that require extended surveillance before and/or during labour. Primary outcome: spontaneous, uncomplicated vaginal delivery. After inclusion, women randomized to proactive support of labour will stay at the hospital and have one-to-one midwife support. If no progression during the next 1–2 hours, amniotomy and/or oxytocin stimulation will be started. The control group will adhere to the standard procedures for labour support: expectance until established regular contractions and 4–5 cm cervical dilatation, and then one-to-one midwife support. Discussion The idea of proactive support of labour is to initiate early intervention when there are signs of slow progress in order to avoid protracted labour with exhaustion of the mother, the uterus and prolonged stress of the foetus. Proactive support of labour may represent a useful method to improve labour support in nulliparous women. However, evidence based on randomized controlled trials are needed in order to know whether proactive support of labour is comparable or superior to standard care. A randomized, controlled trial is described; challenges and possible clinical implications are discussed.publishedVersionThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data

Laboratory investigation of performance of a screen type debris-flow countermeasure

Debris-flows are forms of landslides in mountainous regions that can potentially cause significant damage. Structural countermeasures to mitigate an entire debris-flow may become unrealistically massive and expensive. If the flow cannot be stopped completely, one may alternatively consider reducing the impact and velocity of the flow using energy dissipating structures. A debris-flow screen is such a countermeasure designed to dissipate energy. A screen is made by parallel grids, with some gaps, placed in the direction of the debris-flow on an elevated foundation. This structure acts as a filter for separating water from the saturated debris-flow to reduce its flow energy. This paper presents a laboratory model test investigating the effect of the screen with length (0.5 m and 1.0 m) and opening width (2 mm, 4 mm and 6 mm) in dissipating the debris-flow energy. The effectiveness of the screens was determined in terms of reductions in the run-out distance and the flow velocity. The importance of the screen length and the opening width is demonstrated. A hypothesis that the optimum opening size should be close to of the solid material seems to be validated. The application of the laboratory observations to the field is indicated based on the energy line and scaling principles.acceptedVersionThis is an [Accepted Manuscript] of an article published by Taylor & Francis in [HKIE Transactions] on [31 Jul 2018], available at https://doi.org/10.1080/1023697X.2018.146210

Har du ete frukost i dag?

Ved hjelp av å drøfte forsking, litteratur og eigne erfaringar, har eg kome fram til tiltak som sjukepleiarar kan sette i verk for å førebyggje underernæring hjå ein eldre heimebuande pasient med Alzheimers sjukdom (AD). sjukepleiarar kan førebyggje underernæring ved å identifisere pasienten sine utfordringar på eit tidlig tidspunkt. Kartleggingsverktøyet MNA (Mini Nutritional Assessment) kan gjerne nyttast, det er validert og anbefalt for pasientgruppa eg har fokusert på. For å sikre pasienten sitt matinntak, eller for å oppretthalde appetitten, bør sjukepleiarar ha meir fokus på måltidssituasjopnen hjå kvar enkelt pasient. Godt samarbeid mellom pårørande og heimesjukepleien kan sikre betre oppfølging av pasienten sin ernæringsstatus. Ernæringssupplement kan vere ein god måte å sikre pasienten nok næringstett kost på

Opposition in the Ethiopian diaspora in Norway : mobilizing supporters abroad

Over the past two decades, the Ethiopian opposition diaspora in Norway has increased their mobilizing efforts and civic participation. With a steady influx of Ethiopian migrants and refugees to Norway, the scope of diasporic political activity has expanded. This includes the establishment of opposition groups that mobilize against the Ethiopian government, seeking to bring what they call ‘democratic change’ to their homeland. The aim of this thesis is to provide an overview of the most prominent Ethiopian opposition groups in Norway, and account for some of the causes and mechanisms that can help explain the mobilization of the Ethiopian opposition diaspora in Norway. The thesis will argue that the Ethiopian opposition diaspora is diverse, and consists of movements, organizations and political parties which are motivated by similar grievances, but represent different stances, political projects and aims. While there are many causal factors that could explain diaspora mobilization in Norway, this thesis will primarily highlight the importance of long-term grievances and single incidents and processes such as the 2005 election in Ethiopia, Meles Zenawi’s visit to Norway in 2005, Norwegian asylum politics and the diplomatic relationship between Norway and Ethiopia. Furthermore, a conceptualization of causal mechanisms – supported by concepts from social movement theory – will show that the Ethiopian opposition diaspora in Norway use framing, transnational entrepreneurship, political opportunities and lobbyism to mobilize supporters.submittedVersionM-I