We present a partial implementation of King and Saia 2016’s expected polyno- mial time byzantine agreement algorithm, which which greatly speeds up Bracha’s Byzantine agreement algorithm by introducing a shared coin flip subroutine and a method for detecting adversarially controlled nodes. In addition to implementing the King-Saia algorithm, we detail a new version of the “blackboard” abstraction used to implement the shared coin flip, which improves the subroutine’s resilience from t < n/4 to t < n/3 and leads to an improvement of the resilience of the King-Saia Byzantine agreement algorithm overall. We test the King-Saia algorithm, and detail a series of adversarial attacks against it; we also create a Monte Carlo simulation to further test one particular attack’s level of success at biasing the shared coin flip / Graduate

An employed individual will spend between a quarter and a third of his or her waking life at the workplace. An estimated 40% of those in South Africa who are employed full-time work in offices. With the amount of time spend in buildings, the physical conditions in the workplace are important determinants of satisfaction, comfort, well-being, and effectiveness and can even play a role in mental health. The physical environment in offices should therefore be carefully planned, designed, and managed. This qualitative study, sought to develop an inter-cultural office design framework for South Africa combining Eastern and Western design principles. Specifically, it sought to obtain a better insight into design principles which can enhance the well-being of office workers; inter-cultural, gender neutral and age neutral design principles which can be applied in a South African context. To be able to answer these questions an intensive literature review was undertaken investigating both the Eastern design principles as expressed in feng shui and Western design principles as expressed in Environmental Social Science. The design principles of these two traditions were compared and all aspects where the two traditions did not support each other were included in the in-depth interviews. Twenty-five in-depth interviews were conducted By relying on various design cultures (e.g. Eastern and Western) an environment can be created which are pleasing and can enhance the well-being of the users. Underlying design principles are universal, but the symbolic expression thereof can differ from culture to culture. One of the conclusions from this study is that three quarters of design principles are v universal. There is no one size fits all solution and compromise is necessary from all involved. The compromise applies to the roughly a quarter of design aspects where subgroup differences have been detected. Any design should take individual and group difference into account. The only way to do this is to get proper input from all stakeholders at all stages of the design. It is critically important that the input starts before the design process commences. There are many design principles which can be implemented to improve the quality of work life of office workers in the South African context. Design can for example play a very important role in encouraging and facilitating formal and informal interaction in the workplace – bridging the gap between heterogeneous groups. Without forcing relationships, design can assist in naturally integrating heterogeneous groups. The physical environment must support the image and identity which needs to be communicated, facilitate communication and enable task accomplishment. Most of all it must become a place with which employees can identify and where they can develop a sense of place. From this study it can be concluded that not only form follows function but also that aesthetics follow function – a principle that design should be based on the primary purpose of the building, the workspace based on the needs of the stakeholders and from this starting point aesthetics will flow. / Psychology / D. Litt. et Phil. (Consulting Psychology)

Cette thèse se concentre sur la préparation et l'étude des composites élastomères chargés avec des particules lamellaires et des liquides ioniques. Ces composites sont caractérisés par des propriétés mécaniques améliorées, une diminution du gonflement par les solvants, une faible perméabilité aux gaz ainsi que par une amélioration de la conductivité ionique. Les propriétés de structure et de surface différentes des charges lamellaires, telles que le rapport d'aspect des particules, la surface spécifique et l'activité de surface ont été analysées comme les facteurs impactant le renforcement du caoutchouc nitrile (NBR) et du caoutchouc nitrile carboxylé (XNBR). Une attention particulière a été portée aux systèmes XNBR contenant des hydroxydes doubles lamellaires (MgAI-HDL), qui varient en fonction du rapport Mg / Al et de morphologie de particules. L'application simultanée de MgAI-HDL en tant que charge et en tant qu'agent de réticulation dans XNBR ne fournit pas uniquement un produit écologique sans oxyde de zinc mais également un composite élastomère ionique avec de meilleures propriétés mécaniques, de barrière et de transparence. Cette thèse considère également les applications potentielles des liquides ioniques en tant qu'additifs multifonctionnels dans les composites élastomères afin d'obtenir une bonne dispersion des charges minérales dans une matrice polymère ainsi qu'une amélioration de la conductivité ionique des matériaux composites. La concentration optimale et le type de liquides ioniques ont été sélectionnés pour obtenir un bon compromis entre les propriétés mécaniques et la conductivité des matériaux composites de caoutchouc / This thesis focused on the preparation and the study of elastomer composites filled with layered fillers with improved mechanical properties, decreased swelling in solvents, increased UV stability and reduced gas permeability. The layered minerals were investigated not only in terms of their use as reinforcing fillers for rubbers but also as crosslinking agents, gas barrier and UV stability enhancers. The layered fillers tested belong to a class of cationic clays (natural and synthetic hectorite), anionic clays (hydrotalcites or magnesium aluminum layered double hydroxides MgAI-LDHs) and graphene-based materials. Different structural and surface properties of layered fillers were investigated as factors impacting the reinforcement of acrylonitrile-butadiene rubber (NBR) and carboxylated acrylonitrile-butadiene rubber (XNBR). Special attention has been devoted to the XNBR systems containing MgAI-LDHs varying in Mg / AI ratios, layers aspect ratios and particles morphologies. It was reported that the simultaneous application of MgAI-LDH as a filler and as a crosslinking agent in XNBR provides not only environmentally friendly, zinc-oxide free product but also ionic elastomer composite with improved mechanical, barrier and transparent properties. This thesis considers also the potential application of imidazolium ionic liquids as dispersing agents in rubber matrix, plasticizers and ionic conductivity enhancers. The optimal concentration and type of ionic liquids were selected for obtaining a good compromise between mechanical and conductivity properties of rubber composites

One of the current testing method (the Dry Flow test) to qualify resin for use in production in the rotomolding process has been shown to have many flaws in both equipment and procedure. Research was done here to investigate a possible alternative that could eliminate some of these testing deficiencies. By reducing equipment and operator errors, the testing of materials becomes more valuable of an exercise. The Angular Flow test developed in this research can increase repeatability. By coming to understand the rotational molding process better, an evaluation that can give more valid information was devised.

[pt] O fenômeno associado à estabilidade de tensão se caracteriza pela existência de valores máximos de potência ativa e reativa que podem ser transferidas a uma barra de carga, ou injetada na rede através dos geradores e compensadores síncronos. Sua relevância para o setor elétrico é constantemente reforçada pelo registro de ocorrências de colapsos de tensão em diversos países do mundo e, embora a instabilidade de tensão manifeste-se localmente, suas consequências se refletem na ampla deterioração do sistema. Impulsionado pelo crescente interesse a respeito dos métodos baseados em medições fasoriais sincronizadas para a detecção do máximo carregamento, este trabalho apresenta os principais modelos encontrados na literatura baseados em medições locais e no vasto monitoramento do sistema, com maior ênfase aos métodos de Corsi-Taranto e Circuito Acoplado de Porta-Simples Aprimorado (CAPS Aprimorado). Algumas contribuições são sugeridas ao modelo CAPS Aprimorado tendo em vista sua aplicação ao conjunto de barras de transferência e de geração. Explora-se a utilização dos equivalentes multi-portas como índice de avaliação das condições de estabilidade de tensão, comparando a identificação da barra crítica aos métodos da matriz D e dos autovalores e autovetores. São evidenciadas as principais limitações dos modelos mediante a um conjunto de análises estáticas e dinâmicas, considerando diferentes cenários de carregamento, a sensibilidade dos modelos ao ruído e a resposta dos métodos em face da atuação dos limitadores de sobre-excitação. / [en] The voltage stability phenomenon is characterized by the existence of a maximum active and reactive power that can be transferred to a load bus or injected into the network through the generators and synchronous compensators. Its relevance to the electric power sector is constantly reinforced by the record of occurrences of voltage collapses in several countries around the world. Although the voltage instability manifests itself locally, its consequences is reflected in the wide deterioration of the system. Driven by growing interest in methods based on synchronized phasor measurements for maximum loadability detection, this work presents the main models found in the literature based on local measurements and wide area monitoring, emphasizing the Corsi-Taranto method and Improved Coupled Single-Port Circuit (Improved CAPS). Some contributions are suggested to the Improved CAPS model considering its application to the set of transit and controlled buses. The use of the multi-port equivalents is explored as the evaluation index of voltage stability conditions, comparing the identification of the critical bus to the D matrix method and eigenvalues and eigenvalues method. The main limitations of the models are demonstrated through a static and dynamic studies, as well different loading scenarios, the sensitivity of the models to the noise and the response of the methods when the over-excitation limiters are considered.

If communicating via a teleconference phone the desired transmitted signal (speech) needs to be crystal clear so that all participants experience a good communication ability. However, there are many environmental conditions that contaminates the signal with background noise, i.e sounds not of interest for communication purposes, which impedes the ability to communicate due to interfering sounds. Noise can be removed from the signal if it is known and so this work has evaluated different ways of estimating the characteristics of the background noise. Focus was put on using speech detection to define the noise, i.e. the non-speech part of the signal, but other methods not solely reliant on speech detection but rather on characteristics of the noisy speech signal were included. The implemented techniques were compared and evaluated to the current solution utilized by the teleconference phone in two ways, firstly for their speech detection ability and secondly for their ability to correctly estimate the noise characteristics. The evaluation process was based on simulations of the methods' performance in various noise conditions, ranging from harsh to mild environments. It was shown that the proposed method showed improvement over the existing solution, as implemented in this study, in terms of speech detection ability and for the noise estimate it showed improvement in certain conditions. It was also concluded that using the proposed method would enable two sources of noise estimation compared to the current single estimation source and it was suggested to investigate how utilizing two noise estimators could affect the performance.

There has existed for many years a memory enhancement technique ("memory pegs") that although having dramatic demonstrable success in some individual cases has not been generally applied in education. The emergence of constructivist epistemology has emphasised the notion that learning occurs as a result of connecting new material with previously learnt concepts. There is, therefore, the implication that effective learning requires some previous knowledge upon which to attach new concepts - and thus realisation of the importance of learning with respect to acquiring factual information as a prerequisite to learning new processes and/or skills. This issue has focussed my attention on the need to ensure that the more physiological skills of accessing 'memory', both for learning and recall, are optimised for maximum learning. Further, there are some indications that the physiological skills of memory access (storage and retrieval) may respond favourably to training and 'exercise'. This study was designed to find out whether or not a repeated 'exercise' using a simple memory enhancement technique would lead to a determinable and statistically significant increase in overall performance in a range of cognitive skills (as indicated by science and mathematics examination results), whether learning such a technique would affect a student's attitudes towards science, whether there was a relationship between the amount of time spent practicing the technique and the degree of effect, and whether the memory technique did actually improve the ability to recall lists of objects.

The study investigated the possibility of developing a monitoring and evaluation tool to capacitate the South African Department of Home Affairs towards the sustainability of its mobile unit project. As South Africa has a history of gross discrepancies in the appropriation of services by the citizenry, a fleet of 117 mobile trucks was deployed as part of the 2004 Turnaround Strategy. The chosen structural-functionalist theoretical vantage point informed a quantitative baseline survey in which the views of thirty eight respondents in six provinces and across various ranks were gauged. The majority expressed positive views about the sustainability of the mobile units beyond project phase. They expressed confidence in the goals, relevance and realistic nature of the mobile units. In the SWOT analysis, the respondents expressed more strengths and opportunities than weaknesses and threats. These findings form the baseline for the development of the intended M&E framework. / M.A. (Sociology)

全權委託投資業務(俗稱代客操作),在證券市場中提供專業投資管理服務。我國證期會於民國81年，政策性地決定將開放此項業務。雖然整個規範體系已在民國87年建立，但它忽略掉經濟層面之考量，勢必造成全權委託投資契約無效率。 目前規範體系所允許之委託報酬的計算方法，稱之為「固定佣金制度」，由於此制度無法對業者提供經濟誘因，它會引發業者有嚴重之道德危險發生。因此，為解決誘因問題，應該使用「績效佣金制度」，不過在目前股市環境下，此一制度則引入過高之風險。因此，為解決兩種制度所帶來之問題，本文提出「改良式績效佣金制度」，在此制度下，委託報酬除基於傳統財務績效衡量值外，並基於非財務性績效衡量值，本文稱之為前瞻性績效衡量值（簡稱F-LPM）。 本文使用兩期之「主理人-代理人」模型，推導出最適委託報酬制度以及相關之比較靜態。在基本模式之下，本文進一步探討F-LPM之相關屬性及功能。所得結果與相關文獻一致，首先是，在最適委託報酬制度下，納入F-LPM可降低業者過度地重視短期，因而犧牲了委任人之報酬，這表示F-LPM具有增額資訊內涵。其次，無成本地提高F-LPM之精確度，可增加委任人之報酬。最後，改良式績效佣金制度優於固定佣金制度與績效佣金制度，因為它可降低風險，因而帶給委任人之報酬增加。 第壹章 緒論 第一節 / Discretion account business provides professional investment management service in the securities market. The Securities and Futures Commission decides in policy to approve the business in 1992. Althrough the regulation system of the discretion account business has been established, it will make the advisory contract inefficient with the negligence of economic consideration. The form of advisory fees permitted by the regulation system is 'constant fee system'. Under the system, advisory contract provides no incentive and serious moral harazd will occur. In order to solve the motivation problem, 'performance fee system' should be used. Under the circumstance of Taipei securities market, however, the performance fee system will bring in high risk. Hence, this paper suggests the 'improved performance fee system' to overcome the dilemma born by the performance fee system. In the improved system, advisory fees are based on the traditional performance measure and the fordward-looking performance measure (hereafter F-LPM). With a two-period principal-agent model, this paper develops the optimal reward system and related comparative static. Following the basic model, the paper examines the attributes and function of F-LPM. The findings are consistent with the related literature. First, the inclusion of a F-LPM in reward system can mitigate the potential for the advisor to focus excessively on the short-term at the expense of the investor. That is, F-LPM is incremental informative. Second, costless increases in precision of F-LPM will lead to increase in payoffs for the inveator. Finally, the improved performance fee system is superior to the constant fee system and the performance fee system in that it can reduce risk and results in higher payoffs to the investor.

El present treball constitueix el producte de la recerca d'una solució integral al greu problema social, econòmic i ambiental en què viuen dia a dia centenars de famílies assentades al Parc Porcí de Ventanilla, a Lima-Perú.S'analitza, s'adapta i fa viable l'aplicació de les tecnologies existents a la utilització de les excretes i orins dels porcs i de les aigües residuals dels habitatges com a matèria primera per a la producció de biogàs i altres subproductes, que serveixin com a: font d'energia, de matèries primeres per a la producció orgànica, per a l'ús racional de l'aigua, la planificació del territori i sobretot per la millora dels ingressos de les famílies, tot prioritzant l'ús dels recursos locals i que sigui assumible per les famílies per la seva operació, manteniment i rèplica, la qual cosa va significar treballar en una metodologia participativa involucrant a les famílies en tot el procés. / El presente trabajo constituye el producto de la búsqueda de una solución integral al grave problema social, económico y ambiental en que viven día a día cientos de familias asentadas en el Parque Porcino de Ventanilla, en Lima-Perú.Se analiza, se adapta y hace viable la aplicación de las tecnologías existentes a la utilización de las excretas y orines de los cerdos y de las aguas residuales de las viviendas como materia prima para la producción de biogás y otros subproductos, que sirvan como: fuente de energía, de insumos para la producción orgánica, para el uso racional del agua, la planificación del territorio y sobre todo para la mejora de los ingresos de las familias, todo ello priorizando el uso de los recursos locales y que sea asumible por las familias para su operación, mantenimiento y réplica, lo cual ha significado trabajar en una metodología participativa involucrando a las familias en todo el proceso. / This work results from the search of an integral solution to the very serious social, economical and environmental problems faced by hundreds of families settled in the Porcine Park of Ventanilla in Lima, Peru.The existing technologies have been analyzed, adapted and applied to use with pigs' excreta and urine, as well as with households´ wastewater as a feedstock for the production of biogas and other sub products. These will be used as: source of energy; organic production inputs; better management of water, spatial planning; and above all, for the improvement of households' incomes. This process prioritizes the use of local resources and is designed to be self managed by the families in terms of operation, maintenance and replication. These two objectives required working in a participatory approach that involved all the families throughout the complete process.