Orientador: Rubén Augusto Romero Lázaro / Resumo: Neste projeto de pesquisa, é abordado o problema otimização de grade horária. O tipo de problema de grade horária abordado é aquele que tem o enunciado e a estrutura de dados apresentado no site da Competição Internacional de Otimização do Problema de Grade Horária. Esse problema pode ser modelado como sendo um problema de Programação Linear Binária de grande porte. Entretanto, os solvers comerciais disponíveis, como o CPLEX, não tem a capacidade de encontrar as soluções ótimas das 20 instâncias mostradas no site da Competição Internacional de Otimização do Problema de Grade Horária. Neste trabalho foi desenvolvido um algoritmo VNS especializado para resolver o problema de otimização de grade horária. A parcela inovadora da proposta está relacionado com o uso da lógica de partição para encontrar a melhor solução vizinha da solução corrente de forma eficiente e para uma estrutura de vizinhança complexa e formada por muitos elementos. Dessa forma, a proposta de otimização se tornou muito eficiente na resolução das 20 instâncias cujos dados se encontram no site da Competição Internacional de Otimização do Problema de Grade Horária. / Abstract: In this research project, we address the optimization timetabling problem. The type of timetabling problem addressed is one that has the statement and data structure displayed on the site of the International Competition of Optimization of the Timetabling Problem. This problem can be modeled as a large Binary Linear Programming Problem. However, the commercial solvers available, such as CPLEX, do not have the ability to nd the optimal solutions from the 20 instances shown on the site of the International Competition of Optimization of the timetabling Problem. In this work a specialized VNS algorithm was developed to solve the optimization of Timetabling Problem . The innovative part of the proposal is related to the use of partition logic to nd the best neighborhood solution of the current solution e ciently and to a structure of complex neighborhood formed by many elements. In this way, the optimization proposal became very e cient in the resolution of the 20 instances whose data were found on the website of the International Competition for Optimization of the Timetabling Problem. / Doutor

Enterprise wide area network (WAN) is a private network that connects the computers and other devices across an organisation's branch locations and the data centers. It forms the backbone of enterprise communication. Currently, multiprotocol label switching (MPLS) is commonly used to provide this service. As a recent alternative to MPLS, software-dened wide area networking (SD-WAN) solutions are being introduced as an IP based cloud-networking service for enterprises. SD-WAN virtualizes the networking service and eases the complexity of conguring and managing the enterprise network by moving these tasks to software and a central controller. The introduction of new technologies causes concerns about their security. Also, this new solution is introduced as a replacement for MPLS, which has been considered secure and has been in use for more than 16 years. Thus, there is a need to analyze the security of SD-WAN, which is the goal of this thesis. In this thesis, we perform a security analysis of a commercial SD-WAN solution, by finding its various attack surfaces, associated vulnerabilities and design weaknesses. We choose Nuage VNS, an SD-WAN product provided by Nuage Networks, as the analysis target. As a result, many attack surfaces and security weaknesses were found and reported, especially in the Customer Premises Equipment (CPE). In particular, we found vulnerabilities in the CPE's secure bootstrapping method and demonstrated some attacks by exploiting them. Finally, we propose mitigation steps to avoid the attacks. The results of this thesis will help both the service provider and the SD-WAN solution vendor to know about the attack surfaces and weaknesses of SD-WAN before o ering it to their customers. We also help in implementing the temporary countermeasures to mitigate the attacks. The results have been presented to the service provider and the vendor of the SD-WAN product.

<p>In this dissertation, we show three approaches towards selective vagus nerve stimulation (VNS). First, we investigated VNS using microelectrode with circle and Vicsek fractal shape. Our rat study shows that fractal microelectrode can activate C-fibers in cervical vagus nerve with higher energy efficiency compared to circle microelectrode. Secondly, we developed stretchable and adhesive cuff device for a compliant neural interface for a long-term stability. We designed Y-shaped kirigami thin-film device for stretchable neural interface and applied a tissue-adhesive hydrogel to enable tough adhesion of the cuff electrode, which can be potentially used to fix the position of microelectrode for a reliable selective stimulation with minimal mechanical mismatch. Lastly, we developed a microchannel electrode array device to potentially measure high-quality of single fiber action potential (SFAP) from the abdominal vagal trunk of rat to explore natural patterns selective organ activities which can be used for a fine-tuned selective VNS. Our results show the potential of measuring C-fiber activities evoked by cervical VNS.</p>

Made available in DSpace on 2015-03-03T15:48:41Z (GMT). No. of bitstreams: 1 MatheusSM_TESE.pdf: 3657538 bytes, checksum: 05bf71663b044728a1e70b6db57b834e (MD5) Previous issue date: 2014-03-21 / This paper introduces a new variant of the Traveling Car Renter Problem, named Prizecollecting Traveling Car Renter Problem. In this problem, a set of vertices, each associated with a bonus, and a set of vehicles are given. The objective is to determine a cycle that visits some vertices collecting, at least, a pre-defined bonus, and minimizing the cost of the tour that can be traveled with different vehicles. A mathematical formulation is presented and implemented in a solver to produce results for sixty-two instances. The proposed problem is also subject of an experimental study based on the algorithmic application of four metaheuristics representing the best adaptations of the state of the art of the heuristic programming.We also provide new local search operators which exploit the neighborhoods of the problem, construction procedures and adjustments, created specifically for the addressed problem. Comparative computational experiments and performance tests are performed on a sample of 80 instances, aiming to offer a competitive algorithm to the problem. We conclude that memetic algorithms, computational transgenetic and a hybrid evolutive algorithm are competitive in tests performed / Este trabalho apresenta uma nova variante do problema do Caixeiro Alugador ainda n?o descrita na literatura, denominada de Caixeiro Alugador com Coleta de Pr?mios. Neste problema s?o disponibilizados um conjunto de v?rtices, cada um com um b?nus associado e um conjunto de ve?culos. O objetivo do problema ? determinar um ciclo que visite alguns v?rtices coletando, pelo menos, um b?nus pr?-de nido e minimizando os custos de viagem atrav?s da rota, que pode ser feita com ve?culos de diferentes tipos. ? apresentada uma formula??o matem?tica e implementada em um solver produzindo resultados em sessenta e duas inst?ncias. O problema proposto tamb?m ? objeto de um estudo algor?tmico experimental baseado na aplica??o de quatro metaheur?sticas de solu??o, representando adapta??es do melhor do estado da arte em programa??o heur?stica. Nesse trabalho tamb?m apresentamos a constitui??o de novos operadores que exploram as vizinhan?as do problema, procedimentos construtivos e adapta??es, criados especifi camente para o problema abordado. Experimentos computacionais comparativos e testes de desempenho s?o realizados sobre uma amostra de 80 inst?ncias, visando oferecer um algoritmo de solu??o competitivo para o problema. Conclui-se que algoritmos com abordagem mem?tica, transgen ?tica e evolucion?ria h?brida obtiveram resultados competitivos nos testes efetuados. Palavras-chave: Caixeiro Alugador com Coleta de Pr?mios. Metaheur?sticas. GRASP/VNS. Algoritmo Mem?tico. Transgen?tica Computacional. Computa??o Evolucion?ria

La localisation des personnes et des objets à l’intérieur des bâtiments basée sur les réseaux WLAN connaît un intérêt croissant depuis quelques années ; ce système peut être un parfait complément pour fournir des informations de localisation statique ou dynamique dans des environnements où les techniques de positionnement telles que GPS ne sont pas efficaces. Le manuscrit de thèse propose une nouvelle approche pour définir un système WLAN de positionnement indoor (WLAN-IPS) comme un problème d'optimisation combinatoire afin de garantir à la fois une qualité de communication et une minimisation de l'erreur de positionnement via le réseau. Cette approche est caractérisée par plusieurs questions difficiles que nous abordons en trois étapes.Dans un premier temps, nous avons conçu un réseau WLAN-IPS et mis en œuvre une plateforme de test. Nous avons examiné la performance du système sous diverses contraintes expérimentales et nous nous sommes penchés sur l'analyse des relations entre l'erreur de positionnement et les facteurs environnementaux externes. Ces relations ont permis de proposer des indicateurs pour évaluer l'erreur de positionnement. Ensuite nous avons proposé un modèle physique qui définit tous les paramètres majeurs rencontrés en WLAN-IPS à partir de la littérature. L'objectif initial des infrastructures WLAN étant de fournir un accès radio de qualité au réseau, nous avons introduit un objectif supplémentaire qui est de minimiser l'erreur de localisation dans le contexte IPS. Deux indicateurs principaux ont été définis afin d'évaluer la qualité de service (QoS) et l'erreur de localisation pour LBS (Location-Based Services). Enfin après avoir défini la formulation mathématique du problème d'optimisation et les indicateurs clés de performance, nous avons proposé un algorithme mono-objectif et un algorithme multicritère basés sur Tabu Search et Variable Neighborhood Search pour fournir des bonnes solutions en temps raisonnable. Les simulations montrent que ces deux algorithmes sont très efficaces pour le problème d'optimisation que nous avons posé. / Indoor Positioning Systems (IPS) using the existing WLAN have won growing interest in the last years, it can be a perfect supplement to provide location information of users in indoor environments where other positioning techniques such as GPS, are not much effective. The thesis manuscript proposes a new approach to define a WLAN-based indoor positioning system (WLAN-IPS) as a combinatorial optimization problem to guarantee the requested communication quality while optimizing the positioning error. This approach is characterised by several difficult issues we tackled in three steps.At first, we designed a WLAN-IPS and implemented it as a test framework. Using this framework, we looked at the system performance under various experimental constraints. Through these experiments, we went as far as possible in analysing the relationships between the positioning error and the external environmental factors. These relationships were considered as evaluation indicators of the positioning error. Secondly, we proposed a model that defines all major parameters met in the WLAN-IPS from the literature. As the original purpose of the WLAN infrastructures is to provide radio communication access, we introduced an additional purpose which is to minimize the location error within IPS context. Two main indicators were defined in order to evaluate the network Quality of Service (QoS) and the positioning error for Location-Based Service (LBS). Thirdly, after defining the mathematical formulation of the optimisation problem and the key performance indicators, we proposed a mono-objective algorithm and a multi-objective algorithm which are based on Tabu Search metaheuristic to provide good solutions within a reasonable amount of time. The simulations demonstrate that these two algorithms are highly efficient for the indoor positioning optimization problem.

In recent years, development of various imaging, recording and stimulation tools are rapidly advancing our knowledge of the human anatomy and its underlying interconnections. As a truly non-invasive tool, Magnetic Resonance Imaging (MRI), is creating new opportunities to understand large scale biological processes with a fine detail. Furthermore, novel materials and microfabrication techniques are allowing researchers to develop tools that record bio-signal or modulate complex physiology with high temporal precision. However, these tools, when used individually can elucidate only a partial view of the human body and the brain. There is a growing need in both the research and clinical community to find ways to perform these modalities together and visualize biological systems across a vast range of spatiotemporal scale. However, severe methodological challenges act as bottlenecks for any such multimodal integration.<br><div><br></div><div>To address this critical need, I have designed an MRI-safe platform for high-fidelity bio-signal recording and electrical stimulation during concurrent MRI imaging. Central to this system are novel miniaturized microelectronic devices, that operate wirelessly in synchrony with MRI scans. The system leverages surplus functionalities of a conventional scanner to integrate with the imaging system and provide a simple and inexpensive solution towards multimodal imaging. This work also describes a systematic approach for development and evaluation of this plug-and-play system through in-vivo experiments in animal models. The clinical relevance of the multimodal imaging platform was further showcased through a study on the mechanism of SUDEP (Sudden death in epilepsy), a terminal complication associated with epilepsy. With future refinements, I expect this platform will provide affordable, accessible, and reliable solutions for multimodal imaging in animals and humans, creating unique opportunities for basic scientific research and clinical diagnosis.<br></div>

Frans Vredenrijk Engelenburg (1863-1938) played a major role in the development and expansion of Afrikaans and the Afrikaans academic culture - especially in the northern part of South Africa. As a Dutch intellectual, lawyer and journalist in the nineteenth century South African Republic (Transvaal), he in particular played an important role as advisor and opinion maker from the 1890s onward. One of his biggest achievements was the key role that he played in the establishment of De Zuid Afrikaanse Akademie voor Taal, Letteren en Kunst in 1909. This study is the first part of a more comprehensive biographical project on the life of Engelenburg and the role he fulfilled in the history of the Akademie and South Africa until the thirties of the twentieth century. Since the 1600s the Engelenburg family has played a prominent role in the community where they lived. Aside from the high positions they had held for centuries before, they had in the fourth and again in the sixth generation married into noble families. This contributed to their important position in the community. Due to circumstances Engelenburg was not raised in the Engelenburg milieu. A family break in 1836 was the cause that Engelenburg's father, as a baby, was spirited away from this family milieu. Engelenburg received an extraordinarily good schooling. The solid intellectual foundation already laid then, to a large extent determined the course of his life. He was at the Stedelijk Gymnasium Arnhem when he met Marie Koopmans-De Wet (1834-1906), an aunt by marriage who lived in Cape Town, when on a visit to Europe. She was his soul mate and acted as a mentor and advisor to Engelenburg. The friendship strengthened with the years. He already at school had the desire to visit South Africa one day. His parents' divorce when he was still a student at the University of Leyden, steered his life in a very different direction than what he had foreseen for himself. The divorce was to a large extent the reason that, although he had studied law, he discarded the notion of a career in law after only a year. His decision to follow a career in journalism affected the rest of his life. The Transvaal War (1880-1881) meant that the Dutch developed an admiration for the Transvaalers for the determination and courage they displayed in their attempts to defeat the British army. President Paul Kruger's call shortly after the war that the Transvaal needed young Dutchmen further encouraged Engelenburg to come to South Africa. Previously Engelenburg had for a year worked for Fred Hogendorp at the Dagblad van Suidholland en s’Gravenhage in The Hague. Circumstances abruptly changed when Hogendorp suddenly became insane. During the same time, the owner of De Volksstem newspaper in Pretoria had committed suicide and Engelenburg seized the work opportunity. Within a matter of three months, he arrived in the Transvaal. Within a month after his arrival he was appointed chief editor of De Volksstem. He had studied the Transvaal situation thoroughly and by means of the newspaper and through tireless efforts, he contributed to improving the farming community’s cultural literacy. The education situation in the Transvaal enjoyed his constant attention. After the Anglo-Boer War (ABW) (1899-1902), he continued to work towards improving the education system in the Transvaal. He early on became involved in the Transvaal University College (later University of Pretoria). Before the ABW he did everything possible to promote the Dutch language to the Boer people. However, after the war he realised that Afrikaans had a rightful place, and he, in addition to Dutch, became a champion for the Afrikaans language. The battle between the proponents of Dutch and Afrikaans respectively, increased after the ABW. To achieve unity of action between the two groups, De Zuid Afrikaanse Akademie voor Taal, Letteren and Kunst was founded in 1909. Behind the scenes Engelenburg was one of the major driving forces to assist with the founding of the organisation. As a board member and later as chairman, he gave impetus to the Akademie. In 2009 the organisation celebrated its centenary. This is an important milestone, especially seen in the light of the current political climate in South Africa. The Akademie can now be regarded as a monument to Engelenburg as the fruit of his labour and perseverance during the first three decades of the Akademie’s existence. / Thesis (M.A. (History))--North-West University, Vaal Triangle Campus, 2010.

Frans Vredenrijk Engelenburg (1863-1938) played a major role in the development and expansion of Afrikaans and the Afrikaans academic culture - especially in the northern part of South Africa. As a Dutch intellectual, lawyer and journalist in the nineteenth century South African Republic (Transvaal), he in particular played an important role as advisor and opinion maker from the 1890s onward. One of his biggest achievements was the key role that he played in the establishment of De Zuid Afrikaanse Akademie voor Taal, Letteren en Kunst in 1909. This study is the first part of a more comprehensive biographical project on the life of Engelenburg and the role he fulfilled in the history of the Akademie and South Africa until the thirties of the twentieth century. Since the 1600s the Engelenburg family has played a prominent role in the community where they lived. Aside from the high positions they had held for centuries before, they had in the fourth and again in the sixth generation married into noble families. This contributed to their important position in the community. Due to circumstances Engelenburg was not raised in the Engelenburg milieu. A family break in 1836 was the cause that Engelenburg's father, as a baby, was spirited away from this family milieu. Engelenburg received an extraordinarily good schooling. The solid intellectual foundation already laid then, to a large extent determined the course of his life. He was at the Stedelijk Gymnasium Arnhem when he met Marie Koopmans-De Wet (1834-1906), an aunt by marriage who lived in Cape Town, when on a visit to Europe. She was his soul mate and acted as a mentor and advisor to Engelenburg. The friendship strengthened with the years. He already at school had the desire to visit South Africa one day. His parents' divorce when he was still a student at the University of Leyden, steered his life in a very different direction than what he had foreseen for himself. The divorce was to a large extent the reason that, although he had studied law, he discarded the notion of a career in law after only a year. His decision to follow a career in journalism affected the rest of his life. The Transvaal War (1880-1881) meant that the Dutch developed an admiration for the Transvaalers for the determination and courage they displayed in their attempts to defeat the British army. President Paul Kruger's call shortly after the war that the Transvaal needed young Dutchmen further encouraged Engelenburg to come to South Africa. Previously Engelenburg had for a year worked for Fred Hogendorp at the Dagblad van Suidholland en s’Gravenhage in The Hague. Circumstances abruptly changed when Hogendorp suddenly became insane. During the same time, the owner of De Volksstem newspaper in Pretoria had committed suicide and Engelenburg seized the work opportunity. Within a matter of three months, he arrived in the Transvaal. Within a month after his arrival he was appointed chief editor of De Volksstem. He had studied the Transvaal situation thoroughly and by means of the newspaper and through tireless efforts, he contributed to improving the farming community’s cultural literacy. The education situation in the Transvaal enjoyed his constant attention. After the Anglo-Boer War (ABW) (1899-1902), he continued to work towards improving the education system in the Transvaal. He early on became involved in the Transvaal University College (later University of Pretoria). Before the ABW he did everything possible to promote the Dutch language to the Boer people. However, after the war he realised that Afrikaans had a rightful place, and he, in addition to Dutch, became a champion for the Afrikaans language. The battle between the proponents of Dutch and Afrikaans respectively, increased after the ABW. To achieve unity of action between the two groups, De Zuid Afrikaanse Akademie voor Taal, Letteren and Kunst was founded in 1909. Behind the scenes Engelenburg was one of the major driving forces to assist with the founding of the organisation. As a board member and later as chairman, he gave impetus to the Akademie. In 2009 the organisation celebrated its centenary. This is an important milestone, especially seen in the light of the current political climate in South Africa. The Akademie can now be regarded as a monument to Engelenburg as the fruit of his labour and perseverance during the first three decades of the Akademie’s existence. / Thesis (M.A. (History))--North-West University, Vaal Triangle Campus, 2010.