Análise e síntese de antenas e superfícies seletivas de frequência utilizando computação evolucionária e inteligência de enxames

The frequency selective surfaces, or FSS (Frequency Selective Surfaces), are structures consisting of periodic arrays of conductive elements, called patches, which are usually very thin and they are printed on dielectric layers, or by openings perforated on very thin metallic surfaces, for applications in bands of microwave and millimeter waves. These structures are often used in aircraft, missiles, satellites, radomes, antennae reflector, high gain antennas and microwave ovens, for example. The use of these structures has as main objective filter frequency bands that can be broadcast or rejection, depending on the specificity of the required application. In turn, the modern communication systems such as GSM (Global System for Mobile Communications), RFID (Radio Frequency Identification), Bluetooth, Wi-Fi and WiMAX, whose services are highly demanded by society, have required the development of antennas having, as its main features, and low cost profile, and reduced dimensions and weight. In this context, the microstrip antenna is presented as an excellent choice for communications systems today, because (in addition to meeting the requirements mentioned intrinsically) planar structures are easy to manufacture and integration with other components in microwave circuits. Consequently, the analysis and synthesis of these devices mainly, due to the high possibility of shapes, size and frequency of its elements has been carried out by full-wave models, such as the finite element method, the method of moments and finite difference time domain. However, these methods require an accurate despite great computational effort. In this context, computational intelligence (CI) has been used successfully in the design and optimization of microwave planar structures, as an auxiliary tool and very appropriate, given the complexity of the geometry of the antennas and the FSS considered. The computational intelligence is inspired by natural phenomena such as learning, perception and decision, using techniques such as artificial neural networks, fuzzy logic, fractal geometry and evolutionary computation. This work makes a study of application of computational intelligence using meta-heuristics such as genetic algorithms and swarm intelligence optimization of antennas and frequency selective surfaces. Genetic algorithms are computational search methods based on the theory of natural selection proposed by Darwin and genetics used to solve complex problems, eg, problems where the search space grows with the size of the problem. The particle swarm optimization characteristics including the use of intelligence collectively being applied to optimization problems in many areas of research. The main objective of this work is the use of computational intelligence, the analysis and synthesis of antennas and FSS. We considered the structures of a microstrip planar monopole, ring type, and a cross-dipole FSS. We developed algorithms and optimization results obtained for optimized geometries of antennas and FSS considered. To validate results were designed, constructed and measured several prototypes. The measured results showed excellent agreement with the simulated. Moreover, the results obtained in this study were compared to those simulated using a commercial software has been also observed an excellent agreement. Specifically, the efficiency of techniques used were CI evidenced by simulated and measured, aiming at optimizing the bandwidth of an antenna for wideband operation or UWB (Ultra Wideband), using a genetic algorithm and optimizing the bandwidth, by specifying the length of the air gap between two frequency selective surfaces, using an optimization algorithm particle swarm

Estudo da qualidade de serviço de uma aplicação VoIP em ambientes wireless com handoff

This work deals with experimental studies about VoIP conections into WiFi 802.11b networks with handoff. Indoor and outdoor network experiments are realised to take measurements for the QoS parameters delay, throughput, jitter and packt loss. The performance parameters are obtained through the use of software tools Ekiga, Iperf and Wimanager that assure, respectvely, VoIP conection simulation, trafic network generator and metric parameters acquisition for, throughput, jitter and packt loss. The avarage delay is obtained from the measured throughput and the concept of packt virtual transmition time. The experimental data are validated based on de QoS level for each metric parameter accepted as adequated by the specialized literature

Otimização de modelos de predição da perda de propagação aplicáveis em 3,5GHZ utilizando algoritmos genéticos

The telecommunications industry has experienced recent changes, due to increasing quest for access to digital services for data, video and multimedia, especially using the mobile phone networks. Recently in Brazil, mobile operators are upgrading their networks to third generations systems (3G) providing to users broadband services such as video conferencing, Internet, digital TV and more. These new networks that provides mobility and high data rates has allowed the development of new market concepts. Currently the market is focused on the expansion of WiMAX technology, which is gaining increasingly the market for mobile voice and data. In Brazil, the commercial interest for this technology appears to the first award of licenses in the 3.5 GHz band. In February 2003 ANATEL held the 003/2002/SPV-ANATEL bidding, where it offered blocks of frequencies in the range of 3.5 GHz. The enterprises who purchased blocks of frequency were: Embratel, Brazil Telecom (Vant), Grupo Sinos, Neovia and WKVE, each one with operations spread in some regions of Brazil. For this and other wireless communications systems are implemented effectively, many efforts have been invested in attempts to developing simulation methods for coverage prediction that is close to reality as much as possible so that they may become believers and indispensable tools to design wireless communications systems. In this work wasm developed a genetic algorithm (GA's) that is able to optimize the models for predicting propagation loss at applicable frequency range of 3.5 GHz, thus enabling an estimate of the signal closer to reality to avoid significant errors in planning and implementation a system of wireless communication

Um sistema para simular o comportamento de bancos trifásicos de reguladores de tensão usados em sistemas de distribuição de energia elétrica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Análise de desempenho na rede metropolitana de saúde da Universidade Federal do Rio Grande do Norte : um dimensionamento aplicado a telemedicina e a telessaúde utilizando QoS baseado no padrão IEEE 802.1Q

It s notorious the advance of computer networks in recent decades, whether in relation to transmission rates, the number of interconnected devices or the existing applications. In parallel, it s also visible this progress in various sectors of the automation, such as: industrial, commercial and residential. In one of its branches, we find the hospital networks, which can make the use of a range of services, ranging from the simple registration of patients to a surgery by a robot under the supervision of a physician. In the context of both worlds, appear the applications in Telemedicine and Telehealth, which work with the transfer in real time of high resolution images, sound, video and patient data. Then comes a problem, since the computer networks, originally developed for the transfer of less complex data, is now being used by a service that involves high transfer rates and needs requirements for quality of service (QoS) offered by the network . Thus, this work aims to do the analysis and comparison of performance of a network when subjected to this type of application, for two different situations: the first without the use of QoS policies, and the second with the application of such policies, using as scenario for testing, the Metropolitan Health Network of the Federal University of Rio Grande do Norte (UFRN)

Utilização de sistemas dedicados a protocolos de rede aplicados à eficiência energética da iluminação pública

The public illumination system of Natal/RN city presents some recurring problems in the aspect of monitoring, since currently is not possible to detect in real time the light bulbs which are on throughout the day, or those which are off or burned out, at night. These factors depreciate the efficiency of the services provided, as well as, the use of energetic resources, because there is energetic waste and, consequently, financial resources that could be applied at the own public system illumination. The purpose of the work is create a prototype in substitution to the currently photoelectric relays used at public illumination, that have the same function, as well others: turn on or off the light bulbs remotely (control flexibility by the use of specifics algorithms supervisory), checking the light bulbs status (on or off) and wireless communication with the system through the ZigBee® protocol. The development steps of this product and the tests carried out are related as a way to validate and justify its use at the public illumination

Um estudo do aumento da capacidade de sistemas 3g WCDMA usando técnicas 3.5G de expansão do enlace reverso

The introduction of new digital services in the cellular networks, in transmission rates each time more raised, has stimulated recent research that comes studying ways to increase the data communication capacity and to reduce the delays in forward and reverse links of third generation WCDMA systems. These studies have resulted in new standards, known as 3.5G, published by 3GPP group, for the evolution of the third generation of the cellular systems. In this Masters Thesis the performance of a 3G WCDMA system, with diverse base stations and thousand of users is developed with assists of the planning tool NPSW. Moreover the performance of the 3.5G techniques hybrid automatic retransmission and multi-user detection with interference cancellation, candidates for enhance the WCDMA uplink capacity, is verified by means of computational simulations in Matlab of the increase of the data communication capacity and the reduction of the delays in the retransmission of packages of information

Controle inteligente de pressão para uma rede sem reservatório de abastecimento urbano de água

The sanitation companies from Brazil has a great challenge for the XXI century: seek to mitigate the rate of physical waste (water, chemicals and electricity) and financial waste caused by inefficient operating systems drinking water supply, considering that currently we already face, in some cases, the scarcity of water resources. The supply systems are increasingly complex as they seek to minimize waste and at the same time better serve the growing number of users. However, this technological change is to reduce the complexity of the challenges posed by the need to include users with higher quality and efficiency in services. A major challenge for companies of water supplies is to provide a good quality service contemplating reducing expenditure on electricity. In this situation we developed a research by a method that seeks to control the pressure of the distribution systems that do not have the tank in your setup and the water comes out of the well directly to the distribution system. The method of pressure control (intelligent control) uses fuzzy logic to eliminate the waste of electricity and the leaks from the production of pumps that inject directly into the distribution system, which causes waste of energy when the consumption of households is reduced causing the saturation of the distribution system. This study was conducted at Green Club II condominium, located in the city of Parnamirim, state of Rio Grande do Norte, in order to study the pressure behavior of the output of the pump that injects water directly into the distribution system. The study was only possible because of the need we had to find a solution to some leaks in the existing distribution system and the extensions of the respective condominium residences, which sparked interest in developing a job in order to carry out the experiments contained in this research

Desenvolvimento de um protocolo de comunicação para automação de subestações móveis via satélite

One of the most important decisions to turn a substation automatic and no attended it relates to the communication media between this substation and Operation Center. Generally energy companies uses radio or optic fiber, depending of distances and infrastructure of each situation. This rule applies to common substations. Mobile substations are a particular case, therefore they are conceived for use at provisional situations, emergencies, preventive or corrective maintenance. Thus the telecommunication solution used at common substations are not applied so easily to mobile substations, due absence of infrastructure (media) or difficulty to insert the mobile substation data in existing automation network not long. The ideal media must supply covering in a great geographic area to satisfy presented requirements. The implantation costs of this big infrastructure are expensive, however a existing operator may be used. Two services that fulfill that requirements are satellite and cellular telephony. This work presents a solution for automation of mobile substations through satellite. It was successfully implanted at a brazilian electric energy concessionaire named COSERN. The operation became transparent to operators. Other gotten benefits had been operational security, quality in the supply of electric energy and costs reduction. The project presented is a new solution, designed to substations and general applications where few data should be transmitted, but there is difficulties in relation to the media. Despite the satellite having been used, the same resulted can be gotten using celullar telephony, through Short Messages or packet networks as GPRS or EDGE.

e-Pontos: Uma solução embarcada de automação comercial aplicada a clubes de fidelidade baseado em tecnologia RFID e esmart card

In practically all vertical markets and in every region of the planet, loyalty marketers have adopted the tactic of recognition and reward to identify, maintain and increase the yield of their customers. Several strategies have been adopted by companies, and the most popular among them is the loyalty program, which displays a loyalty club to manage these rewards. But the problem with loyalty programs is that customer identification and transfer of loyalty points are made in a semiautomatic. Aiming at this, this paper presents a master's embedded business automation solution called e-Points. The goal of e-Points is munir clubs allegiances with fully automated tooling technology to identify customers directly at the point of sales, ensuring greater control over the loyalty of associate members. For this, we developed a hardware platform with embedded system and RFID technology to be used in PCs tenant, a smart card to accumulate points with every purchase and a web server, which will provide services of interest to retailers and customers membership to the club

Estudo avaliativo de um algoritmo genético auto-organizável e multiobjetivo utilizando aprendizado de máquina para aplicações de telecomunicações

This paper presents an evaluative study about the effects of using a machine learning technique on the main features of a self-organizing and multiobjective genetic algorithm (GA). A typical GA can be seen as a search technique which is usually applied in problems involving no polynomial complexity. Originally, these algorithms were designed to create methods that seek acceptable solutions to problems where the global optimum is inaccessible or difficult to obtain. At first, the GAs considered only one evaluation function and a single objective optimization. Today, however, implementations that consider several optimization objectives simultaneously (multiobjective algorithms) are common, besides allowing the change of many components of the algorithm dynamically (self-organizing algorithms). At the same time, they are also common combinations of GAs with machine learning techniques to improve some of its characteristics of performance and use. In this work, a GA with a machine learning technique was analyzed and applied in a antenna design. We used a variant of bicubic interpolation technique, called 2D Spline, as machine learning technique to estimate the behavior of a dynamic fitness function, based on the knowledge obtained from a set of laboratory experiments. This fitness function is also called evaluation function and, it is responsible for determining the fitness degree of a candidate solution (individual), in relation to others in the same population. The algorithm can be applied in many areas, including in the field of telecommunications, as projects of antennas and frequency selective surfaces. In this particular work, the presented algorithm was developed to optimize the design of a microstrip antenna, usually used in wireless communication systems for application in Ultra-Wideband (UWB). The algorithm allowed the optimization of two variables of geometry antenna - the length (Ls) and width (Ws) a slit in the ground plane with respect to three objectives: radiated signal bandwidth, return loss and central frequency deviation. These two dimensions (Ws and Ls) are used as variables in three different interpolation functions, one Spline for each optimization objective, to compose a multiobjective and aggregate fitness function. The final result proposed by the algorithm was compared with the simulation program result and the measured result of a physical prototype of the antenna built in the laboratory. In the present study, the algorithm was analyzed with respect to their success degree in relation to four important characteristics of a self-organizing multiobjective GA: performance, flexibility, scalability and accuracy. At the end of the study, it was observed a time increase in algorithm execution in comparison to a common GA, due to the time required for the machine learning process. On the plus side, we notice a sensitive gain with respect to flexibility and accuracy of results, and a prosperous path that indicates directions to the algorithm to allow the optimization problems with "η" variables

Uma arquitetura baseada em SCTP e SIP para suporte a aplicações VoIP móveis e a especificação formal do seu módulo de controle

New versions of SCTP protocol allow the implementation of handover procedures in the transport layer, as well as the supply of a partially reliable communication service. A communication architecture is proposed herein, integrating SCTP with the session initiation protocol, SIP, besides additional protocols. This architecture is intended to handle voice applications over IP networks with mobility requirements. User localization procedures are specified in the application layer as well, using SIP, as an alternative mean to the mechanisms used by traditional protocols, that support mobility in the network layer. The SDL formal specification language is used to specify the operation of a control module, which coordinates the operation of the system component protocols. This formal specification is intended to prevent ambiguities and inconsistencies in the definition of this module, assisting in the correct implementation of the elements of this architecture

Caminhos para a universalização dos serviços de água e esgotos no Brasil: a atuação das entidades reguladoras para indução da eficiência dos prestadores de serviços

The deficit of water and sewerage services is a historic problem in Brazil. The introduction of a new regulatory framework, in 2007, presented ways intending to overcome these deficits, among them, the providers efficiency improvement. This thesis aims to analyze the regulators performance regarding its ability to induce the efficiency of the Brazilian water and sewerage services providers. To this end, an analytical approach based on a sequential explanatory strategy was used, and it consists of three steps. In the first step, the Data Envelopment Analysis ( DEA ) was used to measure the providers efficiency in 2006 and 2011. The results show that the average efficiency may be considered high; however significant inefficiencies among the 29 analyzed providers were detected. The ones in the Southeast region showed better performance level and Northeast had the lowest. The local and the private providers were more efficient on average. In 2006 and 2011 the average performance was higher among non-regulated providers. In 2006 the group regulated by local agencies had the best average performance, in 2011, the best performance was the group regulated by the consortium agencies. To analyse the second step was used the Malmquist Index, it pointed that the productivity between 2006 and 2011 dropped. The analysis through decomposing Malmquist Index showed a shift of technical efficiency frontier to a lower level, however was detected a small provider s advance towards the frontier. Only the Midwest region recorded progress in overall productivity. The deterioration in the total factor productivity was higher among regional providers but the local ones and the private agencies moved quickly to the frontier level. The providers regulated from 2007 showed less decrease on the total productivity and the results of the catch up effect were more meaningful. In the last step, the regulators standardization activity analyses noted that there are agencies that had not issued rules until 2011. The most standards topics discussed in the issued rules were the tariff adjustments and the setting of general conditions for the provision and use of services; in another hand, the least covered topics were new technologies incentive and the introduction of efficiency-inducing regulatory mechanisms and productivity gains for price reviews. Regulators created from 2007 were more active proportionately. Even with the advent of the regulatory framework and the creation of new regulatory bodies, the evidence points to a reality in which the actions of these agencies have not been ensuring that providers of water and sewage, regulated by them, has achieved better performance. The non- achievement of regulatory goals can be explained by the incipient level of performance of the Brazilian regulatory authorities, which should be strengthened because of its potential contribution to the Brazilian basic sanitation department

Diagnóstico do usuário no aprimoramento dos serviços de tecnologia da informação: um projeto de intervenção para o Ministério Público do Estado do Rio Grande do Norte

The information tecnology (IT) has, over the years, gaining prominence as a strategic element and competitive edge in organizations, public or private. In the judiciary, with the implementation of actions related to Judiciário Eletrônico, information technology (IT), definitely earns its status as a strategic element and significantly raises the level of dependence of the organs of their services and products. Increasingly, the quality of services provided by IT has direct impact on the quality of services provided by the agency as a whole. The Ministério Público do Estado do Rio Grande do Norte (MPRN) deployments shares of Electronic Government, along with an administrative reform, beyond these issues raised, caused a large increase in institutional demand for products and services provided by the Diretoria de Tecnologia da Informação (DTI), a sector responsible for the provision of IT services. Taking as starting point strategic goal set by MPRN to reach a 85% level of user satisfaction in four years, we seek to propose a method that assists in meeting the goal, respecting the capacity constraints of the IT sector. To achieve the proposed objective, we conducted a work in two distinct and complementary stages. In the first step we conducted a case study in MPRN, in which, through an internal and external diagnosis of DTI, accomplished by an action of internal consulting and one research of the user satisfaction, we seek to identify opportunities of change seeking to raise the quality perceived of the services provided by the DTI , from the viewpoint of their customers. The situational report, drawn from the data collected, fostered changes in DTI, which were then evaluated with the managers. In the second stage, with the results obtained in the initial process, empirical observation, evaluation of side projects of quality improvement in the sector, and validation with the managers, of the initial model, we developed an improved process, gazing beyond the identification of gaps in service a strategy for the selection of best management practices and deployment of these, in a incremental and adaptive way, allowing the application of the process in organs with little staff allocated to the provision of information technology services

Ajuda mútua nos CAPS: o papel dos serviços no empoderamento dos usuários

The research objective is explore practices to mutual help between CAPS users from the east and west regions of the city of Natal, RN, in Brazil. In the mental health field, we observe the care from substitutive services is based on technical knowledge where the person of the mental health professional is predominant. The Brazilian psychiatry reform invests in equipments and mental health care protocols, but it is necessary to invest more vigorously in new strategies and actors capable of obtaining resources to achieve this goal, such as the users. If one cornerstone of the psychiatric reform consists of changing the type of relationship established with the person with mental disorders, why this relationship, nowadays, is still dominated by technique and unevenness, where on one side we have a person who knows something and who needs take care of someone, and on other side we have another who knows nothing and thus needs to be cared for? Starting from this problematization of the traditional methods of health/mental health care, an attempt was made to investigate in what ways the mutual help practices between people with mental disorders can realize potential avenues not yet explored within the scope of psychiatric reform. The objective of this research was to map possible mutual help practices among the users, and the technical understanding of such practices. For that, we took part in the daily activities of the CAPS, mapping the experiences of mutual help among users. In addition, we accompanied the users in external activities (such as return home, trips, etc), and we had roundtables with the professionals. The research was guided by theoretical methodological references of the institutional analysis. The results pointed to a lack of behaviors of mutual help or support among users, something that can probably be explained by the service work dynamics, as well as the relationship between technicians and users, which has a tendency to create hurdles for meetings among users, as well as being non-conducive to theirempowerment