The variance of closed geodesics in balls and annuli on the modular surface

We asymptotically estimate the variance for the distribution of closed geodesics in small random balls or annuli on the modular surface $\Gamma\backslash\mathbb{H}$. A probabilistic model in which closed geodesics are modeled using random geodesic segments is proposed, and we rigorously analyze this model using mixing of the geodesic flow in $\Gamma\backslash\mathbb{H}$. This leads to a conjecture for the asymptotic behavior of the variance, which unlike in previously explored cases is not equal to the expected value. We prove this conjecture for small balls and annuli, resolving a question left open by Humphries and Radziwill.Comment: 32 pages, 5 figure

Modeling Deception for Cyber Security

In the era of software-intensive, smart and connected systems, the growing power and so- phistication of cyber attacks poses increasing challenges to software security. The reactive posture of traditional security mechanisms, such as anti-virus and intrusion detection systems, has not been sufficient to combat a wide range of advanced persistent threats that currently jeopardize systems operation. To mitigate these extant threats, more ac- tive defensive approaches are necessary. Such approaches rely on the concept of actively hindering and deceiving attackers. Deceptive techniques allow for additional defense by thwarting attackers’ advances through the manipulation of their perceptions. Manipu- lation is achieved through the use of deceitful responses, feints, misdirection, and other falsehoods in a system. Of course, such deception mechanisms may result in side-effects that must be handled. Current methods for planning deception chiefly portray attempts to bridge military deception to cyber deception, providing only high-level instructions that largely ignore deception as part of the software security development life cycle. Con- sequently, little practical guidance is provided on how to engineering deception-based techniques for defense. This PhD thesis contributes with a systematic approach to specify and design cyber deception requirements, tactics, and strategies. This deception approach consists of (i) a multi-paradigm modeling for representing deception requirements, tac- tics, and strategies, (ii) a reference architecture to support the integration of deception strategies into system operation, and (iii) a method to guide engineers in deception mod- eling. A tool prototype, a case study, and an experimental evaluation show encouraging results for the application of the approach in practice. Finally, a conceptual coverage map- ping was developed to assess the expressivity of the deception modeling language created.Na era digital o crescente poder e sofisticação dos ataques cibernéticos apresenta constan- tes desafios para a segurança do software. A postura reativa dos mecanismos tradicionais de segurança, como os sistemas antivírus e de detecção de intrusão, não têm sido suficien- tes para combater a ampla gama de ameaças que comprometem a operação dos sistemas de software actuais. Para mitigar estas ameaças são necessárias abordagens ativas de defesa. Tais abordagens baseiam-se na ideia de adicionar mecanismos para enganar os adversários (do inglês deception). As técnicas de enganação (em português, "ato ou efeito de enganar, de induzir em erro; artimanha usada para iludir") contribuem para a defesa frustrando o avanço dos atacantes por manipulação das suas perceções. A manipula- ção é conseguida através de respostas enganadoras, de "fintas", ou indicações erróneas e outras falsidades adicionadas intencionalmente num sistema. É claro que esses meca- nismos de enganação podem resultar em efeitos colaterais que devem ser tratados. Os métodos atuais usados para enganar um atacante inspiram-se fundamentalmente nas técnicas da área militar, fornecendo apenas instruções de alto nível que ignoram, em grande parte, a enganação como parte do ciclo de vida do desenvolvimento de software seguro. Consequentemente, há poucas referências práticas em como gerar técnicas de defesa baseadas em enganação. Esta tese de doutoramento contribui com uma aborda- gem sistemática para especificar e desenhar requisitos, táticas e estratégias de enganação cibernéticas. Esta abordagem é composta por (i) uma modelação multi-paradigma para re- presentar requisitos, táticas e estratégias de enganação, (ii) uma arquitetura de referência para apoiar a integração de estratégias de enganação na operação dum sistema, e (iii) um método para orientar os engenheiros na modelação de enganação. Uma ferramenta protó- tipo, um estudo de caso e uma avaliação experimental mostram resultados encorajadores para a aplicação da abordagem na prática. Finalmente, a expressividade da linguagem de modelação de enganação é avaliada por um mapeamento de cobertura de conceitos

Witchcraft, violence and everyday life: an ethnographic study of Kinshasa

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThe inhabitants of Kinshasa, who call themselves Kinois, deal with insecurity and violence on a daily basis. Cheating and thefts are commonplace, and pillaging by street gangs and robberies by armed thieves are everyday occurrences. The state infrastructure is so poorly regulated that deaths by accident or medical negligence are also common. This, and much more, contributes to a challenging social milieu within which the Kinois’ best hope is simply to ‘make do’. This thesis, based on extensive fieldwork in Kinshasa, analyses different forms of violence which affect the Kinois on a daily basis. I argue that the Kinois’ concept of violence, mobulu, differs from Western definitions, which define violence as an intrinsically negative and destructive force. Mobulu is for the Kinois a potentially constructive phenomenon, which allows them to build relationships, coping strategies and new social phenomena. Violence is perceived as a transformative force, through which people build meaningful lives in the face of the hardship of everyday life. Broadly speaking, this thesis contributes to the Anthropology of violence which has too often focused on how violence is imposed upon a population, often from a structural level of a state and its institutions. Such an approach fails to account for the nuances of alternate perspectives of what ‘violence’ is, as evidenced in this thesis through the prism of the Kinois term mobulu. The concept of mobulu highlights the creativity of those forced to ‘make do’ on the streets of Kinshasa, to negotiate not only every day physical needs, for food and shelter, but also to navigate the mystical violence of witchcraft. By exploring the coping mechanisms across all sections of society, I analyse how the Kinois not only have built their lives in the wake of the violence of the state, but they have also found means of empowerment within it, using mobulu as a springboard for the development of some social phenomena. Whereas the anthropology of violence has focused mainly on physical and material violence, this thesis also argues that mobulu in Kinshasa is a total social fact that combines state violence with everyday violence, and physical violence with the invisible violence of witchcraft. This thesis seeks to enrich discussions on witchcraft in Kinshasa and in the African context in general, by analysing in depth how the cosmology of Kinshasa has differentiated itself as a result of the politico-economic events of recent decades. As witchcraft and material insecurity go hand in hand, a detailed analysis of the mechanisms of witchcraft is necessary, if we are to grasp the complexity of the concept of mobulu and how material and invisible violence inform each other.Brunel University Isambard Doctoral Scholarshi

Investigations into new methods for the efficient and environmentally benign catalytic asymmetric epoxidation of alkenes

PhDThis thesis presents our investigations into the catalytic asymmetric epoxidation of alkenes. An introductory chapter highlights the importance of chirality in nature and industry. It focuses on a few relevant examples of syntheses in which the use of optically pure epoxides as building blocks is fundamental to the overall stereochemistry of the product. The introduction then continues describing the advances in the field of asymmetric epoxidation of olefins; it contains a review of a wide range of the ligands and metals employed in the recent literature together with a range of different oxidants. A section on organocatalytic epoxidations concludes this chapter. A second chapter presents attempts to impart enantioselectivity in the epoxidation of olefins by employing chiral additives (BINOL derivatives) in conjunction with a known oxidising system, TMTACN/manganese with hydrogen peroxide as the oxidant. A brief electrochemical study of the redox potential of the catalytic systems described in this chapter and a study of the effect of the electronic properties of the substrates on the reaction is also reported. The third and fourth chapters describe the synthesis of a series of tri- tetra- and pentadentate ligands based on the backbone of L-proline and trans-diaminocyclohexane. The chapters contain the results of the screening of the above mentioned ligands in the epoxidation of alkenes with a number of metal salts using either hydrogen peroxide or peracetic acid as the oxidant. Single crystal X-ray structures of some of the new ligands are also presented herein. A final experimental chapter presents the supporting characterisation data associated with the compounds synthesised

Catalytic and mechanistic studies into the epoxidation of styrenes using manganese complexes of structurally similar polyamine ligands

The synthesis and catalytic activity of manganese(ii) complexes of two polyamine ligands is reported which highlights how a small structural change in the ligand affects the overall catalytic behaviour.</p

No-tension bodies: A reinforcement problem

In this work we show that the framework put forward by Lucchesi et al. (2006) to study the equilibrium configurations of panels made of no-tension material can be easily extended to the case of a no-tension material with a reinforcing tensile resistant unidimensional material. This kind of bodies could be used to describe reinforced concrete structures. By solving the equilibrium equations we find a family of solutions each of which is characterized by a singular curve where the stress in the no-tension material concentrates. We show that among these, the curve that minimizes the maximum stress resembles the line tension found experimentally on reinforced concrete beams.© 2012 Elsevier Masson SAS. All rights reserved

Genetic analysis of multiple fruit quality traits in mango across sites and years

A key strategy to improve fruit quality and consumer appeal in mangoes is to breed trait improvements into new cultivars. There are several key fruit quality traits in mango. Knowledge of the heritability and relationship among these traits is important for breeding success. This paper implements a linear mixed model analysis including paternal information for analysis of 13 important fruit quality traits from mango cultivars planted across three environments and assessed over several seasons. The traits analysed were average fruit weight, skin background colour, blush colour, percentage blush, blush intensity, skin thickness, beak shape, stem-end shape, deformities, mesocarp colour, mesocarp texture, seed width and mesocarp recovery. The analysis allows investigation into trait heritabilities and stability of traits over years and sites, as well as genetic correlations among traits

Modelagem térmica de transformadores – método de regressão linear múltipla para previsão de variáveis

For the proper operation of transformers, the temperature control is fundamental, since temperature is the main limiting factor for the load of the transformer, directly affecting its lifespan. In this context, this work aims to study the thermic behaviour of transformers using data acquisition, using the database generated by the supervisory system and climate data collected by a meteorological station installed in the substation area, using linear regression analysis tool, and searching for correlations between the temperature of the transformer and other operational parameters. The correlation analysis aims to verify the statistical inferences of the linear association parameters such as the multiple correlation coefficient, which measures the “strength”” or “degree” of linear relation between a variable and a set of other variables. This way, it is possible to generate a tendency for the temperature rise curve of the transformer and parameters such as its load. Therefore, an application to predict the thermal variables of a three-phase 230/138/13.8, 150 MVA transformer using oil, windings and room temperatures and active power collected in intervals of 5 minutes was developed. After treatment and tabulation of the collected information, various correlation situations were studied in each analysis, were one parameter was chosen as main or dependent. By the end of the simulations, the r-square value for each scenario was found, and consequentially the equations that represent the dependent variable. By recalculating the dependent variable through these equations, it was noticed that the best equation for the prediction of load and temperature situations was the one that used more independent variables, being the one closest to the value measured by the SAGE supervisory. Ultimately, through system modelling, this tool can be incorporated to the SCADA system in the operation centre of the power distribution companies to assist on equipment temperature prediction analysis on critical situations, or as an assist tool for data refreshment in case of a failure on the acquisition equipment.Para operação do transformador, o controle de temperatura desempenha papel fundamental, visto que esta é o principal limitante para o carregamento do transformador, afetando diretamente a sua vida útil. Dentro deste contexto este trabalho se propõe a estudar o comportamento térmico de transformadores com base nos dados do seu histórico gerado pelo sistema supervisório, e nos dados do clima gerados por uma estação meteorológica instalada na subestação. Este estudo utiliza a regressão linear para encontrar correlações entre a temperatura do transformador e outros parâmetros de operação. A análise de correlação tem o objetivo de verificar as inferências estatísticas das medidas de associação linear como o coeficiente de correlação múltiplo, que verifica a “força” ou “grau” de relacionamento linear entre uma variável e um conjunto de outras variáveis. Com esta informação levanta-se a tendência para a curva de elevação de temperatura do transformador e parâmetros como o seu carregamento. Foi então realizada uma aplicação de previsão das variáveis térmicas de um transformador trifásico 230/138/13,8 kV, 150 MVA utilizando temperatura do óleo, temperatura dos três enrolamentos, temperatura ambiente e potência ativa durante uma janela de observação de 7 dias com intervalos de 5 minutos entre as coletas. Após o tratamento e a tabulação das informações coletadas, foram estudas situações diversas de correlação sendo em cada análise escolhido um parâmetro como principal, ou dependente. Ao final das simulações foram encontrados alguns valores de R quadrado para cada situação, e consequentemente equações que representam a variável dependente. Ao se calcular a variável dependente com as equações encontradas, notouse que a melhor equação para predição de situações de carregamento e de temperatura, foi aquela que utilizou mais variáveis independentes sendo os valores calculados mais proximos ao valor medido pelo supervisório SAGE. Finalmente, a partir da modelagem do sistema, a ferramenta poderá ser incorporada ao sistema SCADA do centro de operações das concessionárias de energia para auxílio nas análises de previsão de temperaturas do equipamento em situações críticas, ou mesmo, pode servir de auxílio para substituição em tela dos valores em caso de falha do equipamento de aquisição

Area-wide management of methyl eugenol attracted fruit flies in mango: a systems approach

Fruit flies are one of the most serious horticultural pests globally, causing catastrophic damage to fruit and vegetable crops. Significant economic losses negatively affect the livelihoods of millions of large and small-scale farmers. Finding effective and sustainable ways to manage fruit fly infestation is a priority for many countries, and area-wide management is one of the most promising strategies. Drawing on knowledge and experience gained from 3 major ACIAR-funded projects in Indonesia and the Philippines projects, this manual is a comprehensive and practical guide for the implementation of an area-wide management system (AWM system) to manage methyl eugenol-attracted flies in mango crops. The manual presents key concepts, principles, steps and techniques, and it will help growers, extension officers, researchers and communities in tropical and subtropical regions to manage fruit fly infestation