Analyses of experiments and a functional model for ship rolling

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Simulation techniques and a Volterra functional polynomial are applied as two alternative methods of calculating ship roll response to irregular waves. The roll motion is modeled by a single degree of freedom differential equation, with two alternative nonlinear damping functions. Estimation techniques are developed to obtain the coefficients of the damping functions from decay tests and from forced rolling tests. A linear plus quadratic form of damping function is found to be slightly preferable to a linear plus cubic form. The roll response process is found to be non-Gaussian, and characterised by negative values of the coefficient of kurtosis. Simulation results agree well with results obtained from the functional polynomial for low response levels, but show increasing disagreement as the response level increases, due to divergence of the functional polynomial representation. Analyses of results from model tests in irregular waves and from sea trials confirm the non-Gaussian nature of the roll response. A "constrained" form of the generalised gamma distribution function is found to provide an improved fit to the roll maxima and tothe roll minima, as compared to the Rayleigh distribution. The model tests also show some asymmetry in the roll response, which is not predicted by the theoretical model. It is suggested that this asymmetry may primarily be due to the combined effect of horizontal drift forces and the restraining system used to keep the model on station.Financial support was obtained from: Dr.Techn. Georg Vedeler's Fund for Ship Research; A.S Veritas Research; the Overseas Research Students - ORS Awards Scheme; and the Royal Norwegian Council for Scientific and Industrial Research

The effects of weather and climate change on cycling in northern Norway

Weather is identified as one of many factors that influence the demand for cycling. Weather patterns will change due to expected climate change. The aim of this article is to study the extent to which climate change influences the cycling frequency. The analysis in this article is conducted using an econometric model based on data spanning over four years on weather indicators and the cycling frequency in the Norwegian city of Bodø, which is located north of the Arctic Circle. According to the projections for climate change, both temperature and quantity of precipitation are expected to increase in this area during the next century. An important consequence of changes in the climate in the studied region is the reduced duration of what can be characterised as the winter season. However, this consequence is highly uncertain. When using Norway’s middle projections for climate change by 2050, the analysis shows a moderate increase in cycling frequency of 6.2%. For the reduced winter period, the cycle rate might be two and three times higher in 2050 compared to the current level. Both estimates assume that every other potential impact on cycling rates remain equal

Effectiveness and acceptability of the physical exercise and dietary therapy in a healthy life center

Objective: The high burden of eating disorders (EDs) and limited availability of treatment speaks of a need to explore new avenues for treatment delivery. To understand if new treatment avenues are helpful and acceptable to patients, we investigated the effectiveness of Physical Exercise and Dietary Therapy (PED-t) in participants with bulimia nervosa or binge-eating disorder, and acceptability when the PED-t was implemented in a Healthy Life Center in a municipal primary healthcare service. Method: Exercise physiologists and one dietitian were trained in ED literacy and to run PED-t, before screening women for eligibility. Effectiveness (n = 16) of PED-t and participants' experiences (n = 8) were evaluated by a mixed methods study design. Results were analyzed by relevant statistics and reflexive thematic analysis. Results: Of 19 eligible participants, 16 completed treatment. At post-treatment, the Eating Disorder Examination Questionnaire global score, binge-eating frequency, and symptoms of depression were lower, and nine (56% of completers) were in remission. Participants' treatment experiences were classified into two overarching themes: “competence” and “emotional support.” Participants reported high acceptance for PED-t, the local venue and group format, and felt that PED-t provided them with coping tools and increased mental strength. However, many also spoke of an unmet need to address emotional eating. Discussion: Findings point to a potential for making an effective ED therapy more accessible, and that participants find the local low-threshold delivery within a groupformat helpful. With small adjustments, the PED-t could emerge as a promising firstline treatment for bulimic EDs. Public Significance Statement: Limited access to treatment for EDs, patients' high barriers to help-seeking, and the high rates of limited efficacy from psychotherapy speak of a need to explore new therapies and avenues for delivery. In this study, we build on findings from a controlled ED treatment trial and replicate the beneficial effects and find a high patient acceptance of “physical exercise and diet therapy” implemented in a real, non-clinical setting.publishedVersio

PROBABILISTIC MODELLING FOR RELIABILITY ANALYSIS OF JACKETS

ABSTRACT Experience from recent reliability analyses of jacket platforms is used to discuss selected aspects of probabilistic modelling in more detail. These modelling details can have a significant effect on the computed reliabilities. An overview of basic considerations and failure modes in jacket reliability analysis is included to set the various details into context. Ultimate limit states for jackets in relatively shallow water are emphasised; i.e. quasi-static structural response is applicable. The following topics are considered: (a) Failure modes and some requirements to load and resistance analysis

A ranking method of chemical substances in foods for prioritisation of monitoring, based on health risk and knowledge gaps

Chemical contaminants are present in all foods. Data on the occurrence of contaminants in foods that are often consumed or contain high contaminant concentrations are critical for the estimation of exposure and evaluation of potential negative health effects. Due to limited resources for the monitoring of contaminants and other chemical substances in foods, methods for prioritisation are needed. We have developed a straightforward semi-quantitative method to rank chemical substances in foods for monitoring as part of a risk-based food control. The method is based on considerations of toxicity, level of exposure including both occurrence in food and dietary intake, vulnerability of one or more population groups due to high exposure because of special food habits or resulting from specific genetic variants, diseases, drug use or age/life stages, and the adequacy of both toxicity and exposure data. The chemical substances ranked for monitoring were contaminants occurring naturally, unintentionally or incidentally in foods or formed during food processing, and the inclusion criteria were high toxicity, high exposure and/or lack of toxicity or exposure data. In principle, this method can be used for all classes of chemical substances that occur in foods, both unintended contaminants and deliberately added chemical substances. Foods considered relevant for monitoring of the different chemical substances were also identified. The outcomes of ranking exercises using the new method including considerations of vulnerable groups and adequacy of data and a shortened version based on risk considerations only were compared. The results showed that the resolution between the contaminants was notably increased with the extended method, which we considered as advantageous for the ranking of chemical substances for monitoring in foods.publishedVersio

Risk assessment of methylsulfonylmethane (MSM). Opinion of the Norwegian Scientific Committee for Food and Environment

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Key Lessons from Tailoring Agile Methods for Large-Scale Software Development

We describe advice derived from one of the largest development programs in Norway, where twelve Scrum teams combined agile practices with traditional project management. The Perform program delivered 12 releases over a four-year period, and finished on budget and on time. In this article, we summarize 12 key lessons on five crucial topics, relevant to other large development projects seeking to combine Scrum with traditional project management.Comment: Accepted for publication in IEEE IT Professiona

Risk assessment of melatonin. Opinion of the Norwegian Scientific Committee for Food and Environment

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Metabolic profile in women with bulimia nervosa or binge-eating disorder before and after treatment: secondary analysis from the randomized PED-t trial

Purpose: Chaotic eating and purging behavior pose a risk to the metabolic health of women with bulimia nervosa (BN) and binge-eating disorder (BED). This study reports on one-year changes in blood markers of metabolic health and thyroid hormones in women with BN or BED attending two different treatments. Methods: These are secondary analyses from a randomized controlled trial of 16-week group treatment of either physical exercise and dietary therapy (PED-t) or cognitive behavior therapy (CBT). Blood samples collected at pre-treatment, week eight, post-treatment, and at 6- and 12-month follow-ups were analyzed for glucose, lipids (triglycerides (TG), total cholesterol (TC), LDL cholesterol (LDL-c), HDL cholesterol (HDL-c), apolipoprotein A (ApoA) and apolipoprotein B (ApoB) lipoproteins), and thyroid hormones (thyroxine (T4), thyroid stimulating hormone (TSH), and thyroperoxidase antibodies). Result: The average levels of blood glucose, lipids and thyroid hormones were within the recommended range, but clinical levels of TC and LDL-c were detected in 32.5% and 39.1%, respectively. More women with BED compared with BN had low HDL-c, and a larger increase over time in TC and TSH. No significant differences occurred between PED-t and CBT at any measurement. Exploratory moderator analyses indicated a more unfavorable metabolic response at follow-up among treatment non-responders. Conclusion: The proportion of women with impaired lipid profiles and unfavorable lipid changes, suggests active monitoring with necessary management of the metabolic health of women with BN or BED, as recommended by metabolic health guidelines.publishedVersio

Protocol for risk assessment of “other substances”. The Norwegian Scientific Committee for Food and Environment

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