Fair votes in practice

Criteria for a good voting system have been given particularly careful scrutiny in recent years, with general agreement that the core values are fair results, voter power and choice, and local representation. This paper reexamines the basic ideas of three widely used voting systems, the Single Transferable Vote, List-PR, and Mixed Member Proportional (MMP); and evaluates their performance in terms of both principles and practice. It looks particularly closely at proportionality, examining three aspects:n linearity, the threshold for representation and the threshold for gaining a majority. As regards local representation, an important question is how to design multi-member constituencies. It will be argued that using constituencies based on natural demographic boundaries (such as local government areas) can combine better local representation with stability over time and better proportionality. STV is unsurprisingly best for voter empowerment and choice, as those are parts of its basic idea. Broad conclusions are summarised within the Summary on page 1 of the paper. The paper makes use of recent public availability of large preferential voting data sets for STV elections, making possible new analyses of how STV functions in practice, and of voter behaviour, particularly examining how voters' second preferences relate to their first preferences.Comment: 31 pages, 12 figures, submitted to J Roy Statist Soc A as a potential Discussion Pape

Simulations of directionally-spread waves

The pictures which follow are designed to give a first impression of what is happening at points along the backbone of a duck string in a directionally spread sea; in particular, to look at the correlation between wave-records and instantaneous power at pairs of points at varying distances

Конструкційна міцність багатошарових елементів машин з дефектами структури

У дисертаційній роботі вирішений ряд важливих науково-технічних завдань, які включають в себе обґрунтування моделей і методик розрахунку напружено-деформованого та термопружного стану багатошарових оболонок обертання з міжшаровими дефектами структури. Розроблені алгоритми, програми, методики досліджень та отримані на їх основі теоретикоекспериментальні результати показали наявність нових особливостей деформованого стану розглянутих конструкцій. Побудовано замкнену систему диференціальних рівнянь та відповідні крайові умови незв'язаної стаціонарної задачі термопружного деформування багатошарової композитної оболонки, що дозволяють врахувати деформації поперечного зсуву і трансверсального обтиснення, забезпечити умови механічного і теплового сполучення шарів і умови термомеханічного навантаження на лицьових поверхнях такої оболонки. На основі класичної теорії пружності анізотропного тіла розроблений чисельно-аналітичний підхід розв’язання термопружних незв’язаних крайових задач для циліндричних товстостінних оболонок за умови як ідеального, так і неідеального контакту суміжних шарів по сполученим поверхням. Встановлено вплив температурних навантажень на напружено-деформований стан ущільнення робочого колеса, виготовленого із композиційних матеріалів.В диссертационной работе решен ряд важных научно-технических задач, которые включают в себя обоснование моделей и методик расчета напряженно-деформированного и термоупругого состояния многослойных оболочек вращения с межслойными дефектами структуры. Разработанные алгоритмы, программы, методики исследований и полученные на их основе теоретико-экспериментальные результаты показали наличие новых особенностей деформированного состояния рассматриваемых конструкций. Построено замкнутую систему дифференциальных уравнений и соответствующие краевые условия несвязанной стационарной задачи термоупругого деформирования многослойной композитной оболочки, позволяющие учесть деформации поперечного сдвига и трансверсального обжатия, обеспечить условия механического и теплового сопряжения слоев и условия термомеханической нагрузки на лицевых поверхностях такой оболочки. На основе классической теории упругости анизотропного тела разработан численно-аналитический подход решения термоупругих несвязанных краевых задач для цилиндрических толстостенных оболочек при условии как идеального, так и неидеального контакта соседних слоев по сопряженным поверхностям. Установлено влияние температурных нагрузок на напряженно-деформированное состояние уплотнения рабочего колеса, изготовленного из композиционных материалов. Решена задача прочности и получена величина граничного внутреннего давления комбинированных газовых баллонов высокого давления. Исследовано напряженно-деформированное состояние стеклопластиковых труб в зоне фланцевых соединений в зависимости от жесткости фланцев.The thesis presents number of important scientific and technical problems, which include study models and methods of calculating the stress-strain and the thermoelastic state multilayer shells with interlayer structural defects. The algorithms, programs, research methodology, theoretical and experimental results showed the presence of new features deformed state considered structures. We construct a closed system of differential equations and appropriate boundary conditions unrelated stationary problem thermostatic deformation of the multilayer composite shell that allow for deformations of transverse shear and transversal compression, ensure conditions of mechanical and thermal connection layers and thermomechanical loading conditions on the front surface of this shell. Based on the classical theory of elasticity of an anisotropic body developed numerical-analytical approach solving of thermoelastic unrelated boundary problems for thick-walled cylindrical shells provided ideal and non-ideal contact of adjacent layers on surfaces mated. The influence of temperature loads on the stress-strain state seal rotor made from composite materials was found

Challenges on the interaction of models and policy for pandemic control.

The COVID-19 pandemic has seen infectious disease modelling at the forefront of government decision-making. Models have been widely used throughout the pandemic to estimate pathogen spread and explore the potential impact of different intervention strategies. Infectious disease modellers and policymakers have worked effectively together, but there are many avenues for progress on this interface. In this paper, we identify and discuss seven broad challenges on the interaction of models and policy for pandemic control. We then conclude with suggestions and recommendations for the future

Edinburgh Wave Power Project: Fourth Year Report Volume 1 Of 3

The results of measurements carried out at the National Maritime Institute, Feltham in February 1977 confirmed that scaling l aws operate well over the range from 1/150 to 1/15 and so we believe that it is safe to continue work in small tanks. We have tested ducks on a variety of mountings in the narrow tank over the entire range of sea conditions found at OWS India. The results p rovide sufficient input data for the full-scale power take-off design . We have developed techniques for generating very steep waves and have tested ducks in conditions likely to induce slamming. We are satisfied with duck behaviour in these conditions and do not regard slamming as our most serious problem. Photographs of the tests are contained in Volume 2 of this report. We have explored duck behaviour on mountings of variable compliance, and have discovered some striking effects. We find that there are two regions of efficient operation, one of which requires no restraint in heave . Ducks on mountings 1 with the right compliance can work better than those on fixed mountings and the right compliance can easily be achieved at full scale. Most of our effort has gone into making a wide tank with control of directional characteristics of random seas. Its design may prove of interest to other groups. It was ready for use in January 1978 and the cost e stimates proved accurate . Descriptions of the design and performance will be found in Volume 3 of this report. Results from our first month of experiments on free-floating backbones without ducks show that bending moments fall in the central sections of very long backbones and that static beam theory is difficult to apply. The full-time engineering strength of the team has risen to four with the arrival of Glenn Keller but I am sorry to report that we shall be losing two welcome visitors. Rick Jefferies, who has been working on non-linear problems for his Cambridge doctorate, will be going to CEGB, Marchwood. Ian Young is leaving us to r ead computer science here at Edinburgh. I would like to draw the attention of WESC to r eports by my colleague David Mccomb on polymer additions for hydraulic power transmission, by Graham Dixon on the anomalous heave force behaviour of horizontal cylinders and by Rick J efferies on theoretica l frequency and time domain models for ducks

Slamming tests1

We wanted to understand how ducks behave in extreme conditions. We generated the largest, steepest wave possible in the narrow tank. We varied mounting compliance, position, power take-off and attitude of the model. We measured forces and movements and took sequences of photographs. The data is presented to show some features of the behaviour and to allow further analysis. A continuing problem was to decide when to stop doing the experiments. Every answer posed two more questions

The wide tank

Our aim was to construct a tank with complete control of directional distribution of energy as well as spectral shape. This control is important for several types of wave power device but it is of critical importance for the design of the backbone of a duck string

The clinico-radiological paradox of cognitive function and MRI burden of white matter lesions in people with multiple sclerosis: a systematic review and meta-analysis.

Moderate correlation exists between the imaging quantification of brain white matter lesions and cognitive performance in people with multiple sclerosis (MS). This may reflect the greater importance of other features, including subvisible pathology, or methodological limitations of the primary literature.To summarise the cognitive clinico-radiological paradox and explore the potential methodological factors that could influence the assessment of this relationship.Systematic review and meta-analysis of primary research relating cognitive function to white matter lesion burden.Fifty papers met eligibility criteria for review, and meta-analysis of overall results was possible in thirty-two (2050 participants). Aggregate correlation between cognition and T2 lesion burden was r = -0.30 (95% confidence interval: -0.34, -0.26). Wide methodological variability was seen, particularly related to key factors in the cognitive data capture and image analysis techniques.Resolving the persistent clinico-radiological paradox will likely require simultaneous evaluation of multiple components of the complex pathology using optimum measurement techniques for both cognitive and MRI feature quantification. We recommend a consensus initiative to support common standards for image analysis in MS, enabling benchmarking while also supporting ongoing innovation

Key questions for modelling COVID-19 exit strategies

Combinations of intense non-pharmaceutical interventions ('lockdowns') were introduced in countries worldwide to reduce SARS-CoV-2 transmission. Many governments have begun to implement lockdown exit strategies that allow restrictions to be relaxed while attempting to control the risk of a surge in cases. Mathematical modelling has played a central role in guiding interventions, but the challenge of designing optimal exit strategies in the face of ongoing transmission is unprecedented. Here, we report discussions from the Isaac Newton Institute 'Models for an exit strategy' workshop (11-15 May 2020). A diverse community of modellers who are providing evidence to governments worldwide were asked to identify the main questions that, if answered, will allow for more accurate predictions of the effects of different exit strategies. Based on these questions, we propose a roadmap to facilitate the development of reliable models to guide exit strategies. The roadmap requires a global collaborative effort from the scientific community and policy-makers, and is made up of three parts: i) improve estimation of key epidemiological parameters; ii) understand sources of heterogeneity in populations; iii) focus on requirements for data collection, particularly in Low-to-Middle-Income countries. This will provide important information for planning exit strategies that balance socio-economic benefits with public health