A hacker might use a rogue access point to gain access to a network, this poses athreat to the individuals connected to it. The hacker might have the potential to leakcorporate data or steal private information. The detection of rogue access points istherefore of importance to prevent any damage to both businesses and individuals.Comparing different software that detects rogue access points increases the chanceof someone finding a solution that suits their network. The different type of softwarethat are compared are intrusion detection systems, wireless scanners and a Ciscowireless lan controller. The parameters that are being compared are; cost, compat-ibility, detection capability and implementation difficulty. In order to obtain resultssome of the parameters require testing. As there are three types of software, threeexperiment environments should be conducted. Our research indicates that alreadyexisting network equipment or the size of the network affects the results from theexperiments.

Orientador: Eduardo Martins Morgado / Banca: Maria Crsitina Gobbi / Banca: Adriana Bertoldi Carreto de Castro / Resumo: Em um mundo onde as pessoas estão cada vez mais conectadas, chega o momento em que os objetos também passam a fazer parte da rede de compartilhamentos. Com a possibilidade de conexão de equipamentos por meio de hardware com capacidade de telecomunicação e de processamento para executar moderno software embarcado, é cada vez mais acessível tecnológica e economicamente o desenvolvimento de novos produtos conectados. Esta pesquisa discute parte da evolução da Internet das Coisas (IoT) e de algumas de suas aplicações, propondo a criação de um dispositivo conectado a esta rede. Sendo o objeto deste trabalho a IoT, dentro da grande gama de dispositivos que poderiam ser criados, foi colocado foco em desenvolver uma aplicação para coleta e leitura de dados climáticos. Como metodologia, a partir da pesquisa bibliográfica, será desenvolvido um relatório de pesquisa com construção de um protótipo. Atualmente o mercado dispõe de produtos de alto custo para leitura de dados climáticos, quase sempre importados ou desenvolvidos por empresas multinacionais, havendo pouca tecnologia nacional disponível para consumidores finais. Reserva-se esta a grandes centros de pesquisa de referência nacional. Foi desenvolvido um dispositivo para adequar-se aos fins propostos no trabalho, para responder à questão seria possível desenvolver um dispositivo para coleta e leitura de dados climáticos. O objeto deste trabalho é a Internet das Coisas. O objetivo geral foi verificar as características para desenvo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In a world where people are increasingly connected, comes the time when objects also become part of the share's network. With the possibility of connecting hardware by means of hardware with the capability of communication and processing for the execution of modern embedded software, the development of new connected products is increasingly accessible and economically. This research discusses part of the evolution of the Internet of Things (IoT) and some of its applications, proposing a creation of a device connected to this network. Being the object of this work an IoT, within the wide range of devices that are being inserted, were putted in focus an application for the data collection and reading of climatic data. As a methodology, from the bibliographic research, a research report will be developed with the construction of a prototype. Now a days, the market for high-priced climate data products, almost always imported or by multinational companies, has national technology available to end consumers. Reserves to major research centers of national reference. A device was developed to fit the purposes proposed in the work, to answer the question it would be possible to develop a device for collecting and reading climatic data. The object of this work is the Internet of Things. The general objective was to verify the characteristics for the development of an IoT device to perform the reading of climatic data. The specific objectives were: to define ways to collect climate dat... (Complete abstract click electronic access below) / Mestre

Studien hanterar vilka förväntningar controllers själva har på förändringen av deras roll genom att utföra en kvalitativ fallstudie av detta på en kommunal organisation i Sverige. Det i syfte att skapaen förståelse för controllerns egna förväntningar på förändringen av dess roll inom en kommunal förvaltning i Sverige, genom att analysera de förväntningar som existerar från controllern själv och deras ekonomichef. Sedan controllerrollen började bli vanlig i Sverige under 1970-talet har en vetenskaplig debatt förts kring ämnet angående controllers påverkan, roll och värde i organisationer med studier som även behandlar vinster och potentiella förluster av rollens förändring och hur förväntningar påverkar denna förändring. Därmed finns det anledning att vidarestudera controllers egna förväntningar för att öka förståelsen för detta fenomen och dess påverkan på controllerns roll. Denna studie undersökte controllers egna förväntningar på förändring genom att utföra semistrukturerade intervjuer utifrån en teoretisk referensram baserad på controllerns rollförändring av controllerns roll och förväntningar på controllers. Tre controllers och en ekonomichef intervjuades och intervjuerna spelades in och transkriberades för att sedan tolkas och analyseras. Controllers roller analyserades med hjälp av en figur för kategorisering av controllers och förväntningar genom djupgående analys av controllers svar kring förväntningar, roll och förändring. Studien har kommit fram till att controllers har förväntningar på att arbeta mot mindre hantering av statiska uppgifter och redovisning. Förväntningarna riktar sig även mot att föra närmare samarbeten med verksamheter, utföra analyser och vara delaktiga i projekt. Studien indikerar även att controllers själva kan vara en drivande faktor för denna förändring genom sina arbetsuppgifter och tillvägagångsval i utförandet av dessa. Controllers förväntningar stämmer även väl överens med de förväntningar som finns från Ekonomichef och ledning där ekonomichefen ger uttryck för ledningens förväntningar. Studien fördjupar kunskapen om controllers egna förväntningar och påverkan på sin roll genom att analysera deras förväntningar samt de som finns från ekonomichefen vilket förbättrar förståelsen av rollens förändring. Detta har implikationer för hur tillvägagångssätt av en medveten förändring eller utveckling av rollen bör utformas. Studien öppnar även för fortsatt forskning angående hur dessa förväntningar kan se ut i bland privata företag eller kvantitativa studier av controllers förväntningar. / The study deals with what expectations controllers themselves have in the change of their role by performing a qualitative case study of this phenomenon on a municipal organization in Sweden. The purpose of this study is to create an understanding of the controller's own expectations of the changes of their role within a municipal administration in Sweden, by analyzing the expectations that exist from the controllers themselves and their financial manager. The controller role emerged and became commonplace in Sweden during the 1970s, and an ongoing debate on the subject of the controller's influence, role and value within an organization has been present since, including studies that deal with gains and potential losses of the controller’s roles change and how accompanying expectations affect this change. Thus, there is reason to further study the controllers'own expectations in order to increase the understanding of this phenomenon and its impact. This study examined the controller’s own expectations on changes by conducting semi-structuredinterviews based on a theoretical frame of reference formed around the controller's role, changes in the role and expectations of surrounding the role. Three controllers and one chief financialofficer were interviewed in this study, these interviews were recorded and transcribed as to laterbe and analyzed. The controller’s roles were analyzed using a diagram for categorizing controllers, the expectations were then handled through in-depth analysis of controllers responses concerning expectations, role and change based on the conclusions of the controller's roles in the diagram. The study concluded that Controllers have expectations of working towards less management of statictasks and accounting in order to collaborate closer with businesses, carry out analyzes and beinvolved in projects. Expectations also aim to have closer collaboration with businesses, carrying out analyzes and participating in projects. The study also indicates that controllers themselves can be a driving force for this change through their work tasks and choice of approach in execution. Controller's expectations are also in line with the expectations of the chief financial officer and management with the chief financial officer acting as a conduit for management's expectations. The study expands the knowledge of controller’s own expectations and their influence on theirrole, which furthers the knowledge of the changes of the role. In turn this has implications for how a conscious approach to the change and development of the role ought to be designed. The study also enables continued research on how these expectations can manifest themselves among private companies and quantitative studies.

Most recent research show that the role of the modern controller has changed from thetraditional bean counter towards a business partner role. However, all literature does notagree with this notion, claiming that the controller is still more of a bean counter. Further,what it actually means to be a business partner also differs between researchers. The rolechange has also brought several new challenges for the controller. The purpose of this studyis to examine what it means to be a controller at a consultancy company in the IT industry,and what challenges and opportunities exist for business partnering. This is achieved usingcase study as the research design, including qualitative data from interviews of ten controllersof different seniority. The findings are analyzed through a theoretical framework consistingof role theory combined with previous literature on the topic. The findings of the study showthat the role of the controller at the case company shared more similarities with the traditionaldescription of a bean counter than a business partner. While more elements of businesspartnering started to appear as seniority increases, the controllers still felt like they weredoing too much bean counting activities. However, some opportunities for businesspartnering were still found at the company. The study suggests four major challengescontributing to role issues and hindering the controllers from becoming business partners.The four challenges are related to (1) lack of adaptation to new technology, (2) a centralizedorganizational structure, (3) the interplay between financial and business departments, and (4)accountability issues.

Dans cette thèse nous étudions la problématique de l'association dans les réseaux Wi-Fi. Nous proposons des solutions qui permettent à un contrôleur d'optimiser et de gérer d'une manière centralisée les opérations d'association et de réassociation. L'association est exprimée sous forme de problèmes d'optimisations combinatoires. Les modèles proposés tiennent compte des interférences entre les APs et sont conformes avec la méthode d'accès DCF du standard IEEE 802.11. Dans le premier modèle proposé nous avons considéré le cas d'un réseau saturé dans lequel on suppose que chaque AP dispose en permanence de trames à transmettre. Dans ce modèle, nous avons supposé que toutes les stations d'un même AP ont des chances de transmission équivalentes autrement dit le même nombre d'accès au medium. La fonction objectif proposée offre un bon compromis entre l'amélioration du débit des stations et l'équité. Les résultats numériques obtenus sur des simulations réalistes ont montré l'efficacité de cette solution et présentent une amélioration significative des performances du WLAN par rapport à une association basée sur la valeur du RSSI ou par rapport aux approches existantes. Par la suite, étant donné que l'hypothèse d'un réseau tout le temps saturé n'est pas très réaliste, nous avons proposé une solution qui s'appuie sur des mesures réelles telles que les demandes de débit des stations et les taux d'erreur. Notre solution cherche à équilibrer la charge entre les APs. Plus précisément, nous cherchons à diminuer la charge de l'AP le plus chargé dans le WLAN. Pour évaluer cette charge, nous avons proposé un modèle mathématique qui permet d'estimer le BTF « Busy Time Fraction » d'un AP dans n'importe quelle configuration (schéma d'association). Ce modèle est basé sur un réseau de Markov. Le modèle associé au problème d'optimisation permet de proposer la meilleure association. L'évaluation de cette solution par simulation a montré à quel point notre estimation du BTF est précise, et a aussi montré sa capacité à équilibrer la charge entre les APs et à satisfaire la demande en débit des stations. Pour généraliser cette solution aux nouvelles versions du standard IEEE 802.11 comme 802.11n/ac, nous avons adapté le modèle d'estimation du BTF pour qu'il tienne compte des nouvelles améliorations apportées par les couches physiques et MAC du Wi-Fi telles que l'agrégation des canaux, l'agrégation des trames et le bloc d'acquittement. Ainsi, nous avons proposé une nouvelle métrique qui permet d'exprimer à la fois le BTF d'un AP et les taux d'agrégation de trames de chacune de ces stations. L'évaluation numérique de cette solution a montré l'avantage de la nouvelle métrique par rapport au BTF pour améliorer le débit des stations et l'équilibrage de charge dans le WLAN. Il est à noter que, pour la résolution des problèmes d'optimisation combinatoire formulés dans cette thèse, nous avons utilisé des heuristiques de recherche locale itérative. Ces heuristiques sont basées sur une même structure de voisinage, mais les procédures de recherches sont différentes selon la fonction objectif de chaque modèle. Ce choix est justifié par l'efficacité de la recherche locale à fournir des solutions acceptables dans un temps raisonnable pour des problèmes d'optimisation combinatoire complexes / In this thesis we study the problem of association in Wi-Fi networks. We propose solutions that allow a controller to optimize and manage in a centralized way the operations of association and reassociation. Association is expressed as combinatorial optimization problems. The proposed models consider interference between APs and are compliant with the DCF access method of the IEEE 802.11 standard. In the first model proposed we considered the case of a saturated network in which it is assumed that each AP permanently has frames to transmit. In this model, we have assumed that all the stations of the same AP have equivalent chances of transmission, ie the same number of accesses to the medium. The proposed objective function offers a good compromise between improving station throughput and equity. The numerical results obtained on realistic simulations have shown the effectiveness of this solution and show a significant improvement in WLAN performance compared to an association based on the value of the RSSI or compared to existing approaches. Subsequently, since the hypothesis of a saturated network all the time is not very realistic, we have proposed a solution that relies on real measurements such as station throughput requests and the error rates. Our solution seeks to balance the load between APs. Specifically, we seek to reduce the load of the most heavily loaded AP in the WLAN. To evaluate this load, we have proposed a mathematical model that allows to estimate the BTF "Busy Time Fraction" of an AP in any configuration (association scheme). This model is based on a Markov network. The model combined with the optimization problem allows to propose the best association. The evaluation of this solution by simulation has shown how accurate our BTF estimation, and has also shown its ability to balance the load between APs and satisfy the station throughput demands. To generalize this solution to the new versions of the IEEE 802.11 standard such as 802.11n/ac, we adapted the BTF estimation model to take into account the new improvements made by Wi-Fi on physical and MAC layers such as channel aggregation, frame aggregation and block acknowledgment. Thus, we have proposed a new metric that allows to express both the BTF of an AP and the frame aggregation rates of each of its stations. The numerical evaluation of this solution showed the advantage of the new metric compared to the BTF to improve the station throughputs and load balancing in the WLAN. It should be noted that, for the resolution of the combinatorial optimization problems formulated in this thesis, we used iterative local search heuristics. These heuristics are based on the same neighborhood structure, but the search procedures are different depending on the objective function of each model. This choice is justified by the effectiveness of local research in providing acceptable solutions in a reasonable time for complex combinatorial optimization problems

O objetivo do trabalho é apresentar o desenvolvimento, simulação e resultados práticos de um Sistema de controle de temperatura, para Experimentos Biomédicos que utilizam soluções aquecidas com vazão variável. O Sistema utiliza um Trocador de Calor projetado para aquecer uma solução que entra no dispositivo a uma temperatura inferior ou igual à do ambiente e sai com o valor programado. A solução é aquecida a partir da água de um reservatório com temperatura controlada. O Controlador de temperatura é do tipo proporcional-integral-derivativo digital e utiliza um microcontrolador para implementação do algoritmo de controle, da aquisição do sinal dos sensores de temperatura, do comando de atuadores e da interface com o usuário / The objective of the work is to present the development, simulation and practical results of a temperature control System for Biomedical Experiments that utilize heated solutions with variable outflow. The System uses a Heat Exchanger designed to heat the solution that enters into device with a lower or the same temperature as the environment and leaves with the programmed value. The Biomedical solution is heated using the Heat Exchanger and water of the reservoir where the temperature is controlled. The digital proportional-integral-derivative temperature Controller takes use of a microcontroller for implementation of the control algorithm, data acquisition of the temperature sensors, command of actuators and user interface

Algoritmos de busca do ponto de máxima potência (MPPT) são largamente utilizados para se obter a potência máxima fornecida em sistemas fotovoltaicos. Apesar de existirem diversas técnicas de MPPT, os métodos heurísticos de busca como o método da perturbação e observação (P&O) e o método da Condutância Incremental (InC) são os mais usuais por serem simples e confiáveis. Assim, é proposto uma lei de controle com realimentação da tensão de saída de um painel fotovoltaico (PV) de forma a manter o mesmo operando próximo ao ponto de máxima potência, possibilitando com isso uma melhora do desempenho do algoritmo de P&O e InC inclusive quando o painel PV é submetido a rápidas mudanças na irradiação solar. Além disso, devido às características não lineares dos painéis fotovoltaicos, a utilização de técnicas inteligentes que empregam controladores fuzzy para o controle da tensão terminal do PV, parece ser uma solução viável quando comparada aos controladores clássicos com PI e PID, principalmente, porque tais estruturas de controle proporcionam uma lenta resposta dinâmica e problemas de estabilidade relacionados às oscilações em torno do ponto de máxima potência, decorrente do funcionamento dos algoritmos P&O e InC. / Maximum power point tracking (MPPT) techniques are widely used to achieve the maximum output power of a photovoltaic (PV) system. Although there are many MPPT techniques, the heuristic search methods such as perturb and observe (P&O) and incremental conductance (InC) method are the most commonly used because they are simple and reliable in the pursuit of maximum power point. A control law with feedback of the output voltage of a photovoltaic (PV) panel is proposed, in order to maintain it working nearby the maximum power point, enabling an improvement in the performance of the algorithm for P&O and InC even when the PV array is subjected to rapid changes in solar irradiance. Moreover, due to the nonlinear characteristics of the photovoltaic panels, the technique that employ fuzzy logic control seems to be a viable option when compared with conventional proportional and integral or proportional, integral and derivative controllers, mainly because such control structures provide a slow dynamic response and stability issues related to oscillations around the maximum power point due to operation of P&O and InC algorithms.

Neste trabalho são exploradas as potencialidades e efeitos de possíveis aplicações do UPFC (Unified Power Flow Controller) em redes elétricas. Este recente equipamento da família FACTS, apesar de mais complexo, apresenta rapidez e versatilidade de respostas que podem justificar sua aplicação em redes elétricas. São apresentados modelos matemáticos deste dispositivo, para regime permanente e transitório, utilizando transformações para coordenadas ortogonais. Com base nas respostas obtidas, durante as simulações das aplicações estudadas, pode-se constatar que a tensão série e seu posicionamento angular, introduzidos pelo UPFC, desempenham um importante papel no controle rápido e eficiente do fluxo de potência. Como contribuição deste trabalho, explorou-se a conexão do conversor shunt ao enrolamento terciário de autotransformadores, demonstrando a viabilidade do controle do fluxo de potência nestes equipamentos de transformação. O esquema proposto, instalado em transformadores em paralelo, eleva a disponibilidade de operação do UPFC, aumentando a flexibilidade operativa do sistema em implementações práticas. Através da formulação apresentada, o transformador de acoplamento shunt, convencionalmente utilizado pelo UPFC, apresenta dimensões reduzidas. Foi também examinada a possibilidade de limitação de correntes de curto-circuito, equilibrados ou não, com a ação dos controles do UPFC, particularmente, aprofundando a análise do seu desempenho mais eficiente diante de curtos monofásicos. Os resultados satisfatórios obtidos permitem considerar a viabilidade de limitação destas correntes como um subproduto interessante da atuação deste dispositivo FACTS. / In this thesis, the UPFC (Unified Power Flow Controller) various capabilities and effects for possible network applications, are studied. Although its structure is relatively more complex, when compared to the other FACTS controllers, its fast response and versatility can justify its application within the network. By utilising the orthogonal co-ordinates transform both the steady-state and transient mathematical models of the UPFC, are presented herein. Based on the results obtained and regarding the applications studied, it can be stated that the UPFC series voltage along with its phase angle play an important role for the fast and efficient control of the power flow. As a contribution of the present work, it has been proposed the connection of the shunt converter to the tertiary winding of autotransformers, demonstrating in this way the feasibility for controlling the power flow over such transforming assets. The proposed scheme, which regards two paralleled transformers, offers the UPFC a high operation availability increasing the system operative flexibility in actual implementations. By means of the proposed approach, the shunt coupling transformer, usually utilised in a classical UPFC configuration, presents a reduced size. Also, by utilising the UPFC control actions, it has been examined the possibility of short-circuit limitation over balanced and unbalanced circuits. Particularly, it has been analysed the UPFC most efficient performance towards line-to-ground faults. The satisfactory results obtained lead to consider the UPFC feasibility in limiting such currents; this, as an interesting by-product of this FACTS device action.

O desperdício de alimentos desde sua produção até o consumo, encontra-se, atualmente, no patamar de um terço de tudo o que é produzido no mundo. Durante a etapa de transporte, principalmente de alimentos com alta perecibilidade, tais como frutas e hortaliças, ocorrem perdas consideráveis devido à não utilização de tecnologia adequada de conservação e sua utilização é restrita devido ao seu alto custo. Durante o transporte refrigerado rodoviário de produtos agrícolas perecíveis, a carga transportada é suscetível à diversas aberturas de porta do caminhão refrigerado para a realização das entregas ao longo do percurso. Quando isso ocorre uma carga térmica de massa de ar entra no ambiente refrigerado elevando a temperatura neste momento, causando prejuízos em relação à qualidade do alimento transportado. Desta forma, é proposto neste trabalho uma etapa de pré-resfriamento em momento anterior à abertura das portas do caminhão refrigerado, a fim de se manter a temperatura dentro da faixa ideal de conservação. Para isso utilizou-se a estratégia do Controle PID na redução da temperatura antes da abertura de portas e após estas serem fechadas. Foi obtido um modelo em que foram simuladas aberturas de portas de um caminhão refrigerado utilizando técnicas de controle com o objetivo de manter a temperatura do ar do ambiente refrigerado dentro da faixa ideal. Os resultados obtidos indicam o potencial da utilização do controle de sistemas aliado à estratégia do pré-resfriamento na manutenção da temperatura auxiliando na preservação dos atributos de qualidade de alimentos transportados. Além disso, avalia-se que este modelo possa ser aplicado ao transporte refrigerado de outros alimentos. / Food waste, from its production up to its consumption, currently accounts for one-third of all the food produced in the world. During the transport stage, especially of highly perishable foods, such as fruit and vegetables, considerable losses occur due to not using adequate preservation technology; its use is limited owing to its high cost. Over the refrigerated road transport of perishable agricultural products, the load transported is susceptible to different door openings of the refrigerated truck for the deliveries along the route. When this occurs, an air mass thermal load enters the refrigerated environment elevating the temperature, causing damages to the quality of the food transported. Hence, this work proposes a pre-cooling stage at the moment prior to opening the doors of the refrigerated truck, so as to keep the temperature within the ideal preservation range. For this, PID Controller was employed for reducing the temperature before doors are opened and after they are closed. A model was obtained, whereby the door openings of a refrigerated truck were simulated using control techniques aiming to maintain the temperature of the refrigerated environment air within the ideal range. The results indicate the potential of using the system control combined with the pre-cooling strategy for keeping the temperature, aiding to preserve the quality attributes of the food transported. Besides, this model is believed to be able to be applied to the refrigerated transport of other foods.

Apresenta-se a especificação, projeto e implementação de um controlador de célula flexível aplicado na manufatura, visando ser elemento de um sistema aberto de automação. Este trabalho apresenta uma metodologia de desenvolvimento, cujas fases possuem ferramentas de projeto como a especificação padrão, a análise estruturada e a simulação, que serviram para definir a arquitetura do controlador e a validação do mesmo. A implementação do controlador de célula foi baseada numa arquitetura aberta, e foram utilizados recursos computacionais cujas especificações e interfaces são definidas por padrões reconhecidos internacionalmente. Finalmente, o controlador de célula atingirá um alto grau de flexibilidade permitindo a adaptação do controlador a qualquer processo de manufatura de forma simples, e também poderá ser utilizado como equipamento para o ensino e pesquisa das técnicas modernas aplicadas a automação. / It presents the specification, design, and implementation of the flexible cell controller applied to manufacture, which will be element of the automation open systems. This work presents a suitable development a suitable development methodology, whose steps has design tools as standard specification, structure analysis, and the simulation, which was utilized to the architecture definition and validation of the cell controller. The implementation was based on the open architecture and were used computer resources whose specifications and interfaces are defined by international standards. Finally, the cell controller will achieve a great flexibility which permits the simple adaptation to every manufacture process, and will be an equipment for the education and research of the modern techniques applied to the automation.