Contribuições à análise de robustez de sistemas de controle usando redes neurais

This work develops a robustness analysis with respect to the modeling errors, being applied to the strategies of indirect control using Artificial Neural Networks - ANN s, belong to the multilayer feedforward perceptron class with on-line training based on gradient method (backpropagation). The presented schemes are called Indirect Hybrid Control and Indirect Neural Control. They are presented two Robustness Theorems, being one for each proposed indirect control scheme, which allow the computation of the maximum steady-state control error that will occur due to the modeling error what is caused by the neural identifier, either for the closed loop configuration having a conventional controller - Indirect Hybrid Control, or for the closed loop configuration having a neural controller - Indirect Neural Control. Considering that the robustness analysis is restrict only to the steady-state plant behavior, this work also includes a stability analysis transcription that is suitable for multilayer perceptron class of ANN s trained with backpropagation algorithm, to assure the convergence and stability of the used neural systems. By other side, the boundness of the initial transient behavior is assured by the assumption that the plant is BIBO (Bounded Input, Bounded Output) stable. The Robustness Theorems were tested on the proposed indirect control strategies, while applied to regulation control of simulated examples using nonlinear plants, and its results are presented

Aspectos do gerenciamento de riscos de tecnologia da informação nas empresas: um estudo de caso múltiplos

The information technology - IT- benefits have been more perceived during the last decades. Both IT and business managers are dealing with subjects like governance, IT-Business alignment, information security and others on their top priorities. Talking about governance, specifically, managers are facing it with a technical approach, that gives emphasis on protection against invasions, antivirus systems, access controls and others technical issues. The IT risk management, commonly, is faced under this approach, that means, has its importance reduced and delegated to IT Departments. On the last two decades, a new IT risk management perspective raised, bringing an holistic view of IT risk to the organization. According to this new perspective, the strategies formulation process should take into account the IT risks. With the growing of IT dependence on most of organizations, the necessity of a better comprehension about the subject becomes more clear. This work shows a study in three public organizations of the Pernambuco State that investigates how those organizations manage their IT risks. Structured interviews were made with IT managers, and later, analyzed and compared with conceptual categories found in the literature. The results shows that the IT risks culture and IT governance are weakly understood and implemented on those organizations, where there are not such an IT risk methodology formally defined, neither executed. In addition, most of practices suggested in the literature were found, even without an alignment with an IT risks management process

Aspectos do gerenciamento de riscos de tecnologia da informação nas empresas: um estudo de caso múltiplos

The information technology - IT- benefits have been more perceived during the last decades. Both IT and business managers are dealing with subjects like governance, IT-Business alignment, information security and others on their top priorities. Talking about governance, specifically, managers are facing it with a technical approach, that gives emphasis on protection against invasions, antivirus systems, access controls and others technical issues. The IT risk management, commonly, is faced under this approach, that means, has its importance reduced and delegated to IT Departments. On the last two decades, a new IT risk management perspective raised, bringing an holistic view of IT risk to the organization. According to this new perspective, the strategies formulation process should take into account the IT risks. With the growing of IT dependence on most of organizations, the necessity of a better comprehension about the subject becomes more clear. This work shows a study in three public organizations of the Pernambuco State that investigates how those organizations manage their IT risks. Structured interviews were made with IT managers, and later, analyzed and compared with conceptual categories found in the literature. The results shows that the IT risks culture and IT governance are weakly understood and implemented on those organizations, where there are not such an IT risk methodology formally defined, neither executed. In addition, most of practices suggested in the literature were found, even without an alignment with an IT risks management process

Desenvolvimento de um middleware para comunicação via web services e sua aplicação em sistemas de aquisição de dados industriais

The control of industrial processes has become increasingly complex due to variety of factory devices, quality requirement and market competition. Such complexity requires a large amount of data to be treated by the three levels of process control: field devices, control systems and management softwares. To use data effectively in each one of these levels is extremely important to industry. Many of today s industrial computer systems consist of distributed software systems written in a wide variety of programming languages and developed for specific platforms, so, even more companies apply a significant investment to maintain or even re-write their systems for different platforms. Furthermore, it is rare that a software system works in complete isolation. In industrial automation is common that, software had to interact with other systems on different machines and even written in different languages. Thus, interoperability is not just a long-term challenge, but also a current context requirement of industrial software production. This work aims to propose a middleware solution for communication over web service and presents an user case applying the solution developed to an integrated system for industrial data capture , allowing such data to be available simplified and platformindependent across the network

Utilização da lógica difusa no controle inteligente de sistemas eletro-hidráulicos

Electro-hydraulic servo-systems are widely employed in industrial applications such as robotic manipulators, active suspensions, precision machine tools and aerospace systems. They provide many advantages over electric motors, including high force to weight ratio, fast response time and compact size. However, precise control of electro-hydraulic systems, due to their inherent nonlinear characteristics, cannot be easily obtained with conventional linear controllers. Most flow control valves can also exhibit some hard nonlinearities such as deadzone due to valve spool overlap on the passage´s orifice of the fluid. This work describes the development of a nonlinear controller based on the feedback linearization method and including a fuzzy compensation scheme for an electro-hydraulic actuated system with unknown dead-band. Numerical results are presented in order to demonstrate the control system performance

Avaliação e monitoramento de políticas públicas: criação de um modelo sistêmico aplicado ao Instituto de Assistência Técnica e Extensão Rural do Rio Grande do Norte (EMATER-RN)

The nature of this thesis is interventionist and aims to create an alternative on how to control and evaluate the public policies implementation developed at the Institute for Technical Assistance and Rural Extension of Rio Grande do Norte State. The cenarium takes place in a public institution , classified as a municipality that belongs to the Rio Grande do Norte government and adopts the design science research methodology , where it generates a set of artifacts that guide the development of a computerized information system . To ensure the decisions, the literature was reviewed aiming to bring and highlight concepts that will be used as base to build the intervention. The use of an effective methodology called Iconix systems analysis , provides a software development process in a short time . As a result of many artifacts created by the methodology there is a software computer able of running on the Internet environment with G2C behavior, it is suggested as a management tool for monitoring artifacts generated by the various methods. Moreover, it reveals barriers faced in the public companies environment such as lack of infrastructure , the strength of the workforce and the executives behavior

kit educacional para controle e supervisão aplicado a nível

PEREIRA, J. P. ; CASTRO, B. P. S. ; VALENTIM, R. A. M. . Kit Educacional para Controle e Supervisão Aplicado a Nível. Holos, Natal, v. 2, p. 68-72, 2009

O Insituto do Amicus Curiae no controle de consitucionalide brasileiro: uma abordagem à luz da efetividade do princípio do acesso à justiça

It presents a study about the control of constitutionality, its requirements and beddings. It brings, at first, notions about the concept of constitution, in its most varied aspects, as well as the systems of Control of Constitutionality. It emphasizes, considering the actual Brazilian situation, which passes through constitutional reforms and, therefore, assenting the appearance of an enormous amount of ordinary laws, the legal instability that has formed itself within the national panoram. Because of this situation, the institute of the Control of Constitutionality gains inmportancy as a way of protection of our Great Letter, against possible violations which can unfortunately happen. More ahead in the difuse control of constitutionality argues the new trend of generalization, especially after the recent reform that introduced the general repercussion as new requirement of admissibilidade of the appeal to the Brazilian Supreme Court. In the final chapter brings an analysis on the institute of amicus curiae, arguing its historical origins and its evolution, in the comparative jurisprudence, and the Brazilian right. From then is gone deep the paper of amicus curiae in the constitutionality control and, after quarrel on the difficulties of the Brazilian population to materialize its right before the judiciary, as this new institute could contribute in basic way for the materialization of the constitutional rule of access to justice

Repercussão geral e súmula vinculante: os efeitos no controle difuso

Brazil since its first republican constitution has adopted systems of laws control. The review activity was given to three state powers or functions state, Executive, Legislative and Judiciary. However, it appears that in the country along the constitutional history, has stood considerably the jurisdictional control of the most important control. Initially, back in 1891, Brazil adopted the jurisdictional control of diffuse from U.S, whose role in monitoring of standards is delivered to all organs of the judiciary, which may face a case, put on trial, ascertain whether or not the possibility of applying a law, removing its impact in case of unconstitutionality. In 1969, entered in the second legal model of judicial review, the concentrated control of constitutionality, whose inspiration comes from the positivist theory of Hans Kelsen, and was adopted by the Austrian Constitution of 1920. According to the abstract control the supervision of law is given to a Court or Constitutional Court, responsible for the analysis of the legal constitutionality independent of its application to a specific case. In Brazil the role of concentrated control was handed over exclusively to the Supreme Court, which serves as the Constitutional Court, which accumulates that function with other constitutionally provided jurisdiction. Throughout this period, from 1891 until today, Brazil has maintained a dual system of judicial control of legal constitutionality, where they coexist and harmonize the diffuse control exercised by any organ of the Judiciary, and concentrated control of competence the Supreme Court. However, one must recognize that with the advent of the Federal Constitution of 1988, the concentrated control has emerged on the national stage due to two important factors: the expansion of the legal capacity to sue and the inclusion of other ways control, besides the already known Direct Claim of Unconstitutionality. This concentrated control and projection of the Supreme Court s attempt to become a true constitutional court, led to a relative weakening of diffuse control even when performed by the Brazilian Constitutional Court. In order to become a true constitutional court, all decisions handed down by the Supreme in the exercise of constitutional jurisdiction should have the same weight and the same measure, or at least bring improvement to similar effects, once is the responsible for the final word when it comes to constitutional interpretation. Thus, the writs of certiorari and stare decisis were responsible for profound changes in the diffuse control, allowing the Supreme Court can strengthen its decisions even in the diffuse control. These two institutions have substantially changed the legal status of diffuse control, allowing an extension of the effects of decisions handed down by the Supreme Court, so that you can no longer be said that the effects of this control to restrict the disputing parties in the process

Um ambiente computacional para modelagem simbólica de sistemas físicos lineares

Este trabalho propõe um ambiente computacional aplicado ao ensino de sistemas de controle, denominado de ModSym. O software implementa uma interface gráfica para a modelagem de sistemas físicos lineares e mostra, passo a passo, o processamento necessário à obtenção de modelos matemáticos para esses sistemas. Um sistema físico pode ser representado, no software, de três formas diferentes. O sistema pode ser representado por um diagrama gráfico a partir de elementos dos domínios elétrico, mecânico translacional, mecânico rotacional e hidráulico. Pode também ser representado a partir de grafos de ligação ou de diagramas de fluxo de sinal. Uma vez representado o sistema, o ModSym possibilita o cálculo de funções de transferência do sistema na forma simbólica, utilizando a regra de Mason. O software calcula também funções de transferência na forma numérica e funções de sensibilidade paramétrica. O trabalho propõe ainda um algoritmo para obter o diagrama de fluxo de sinal de um sistema físico baseado no seu grafo de ligação. Este algoritmo e a metodologia de análise de sistemas conhecida por Network Method permitiram a utilização da regra de Mason no cálculo de funções de transferência dos sistemas modelados no software

Estudo comparativo de estratégias de controle aplicadas a um gerador síncrono

The robustness and performance of the Variable Structure Adaptive Pole Placement Controller are evaluated in this work, where this controller is applied to control a synchronous generator connected to an infinite bus. The evaluation of the robustness of this controller will be accomplished through simulations, where the control algorithm was subjected to adverse conditions, such as: disturbances, parametric variations and unmodeled dynamic. It was also made a comparison of this control strategy with another one, using classic controllers. In the simulations, it is used a coupled model of the synchronous generator which variables have a high degree of coupling, in other words, if there is a change in the input variables of the generator, it will change all outputs simultaneously. The simulation results show which control strategy performs better and is more robust to disturbances, parametric variations and unmodeled dynamics for the control of Synchronous Generator

kit educacional para controle e supervisão aplicado a nível

PEREIRA, J. P. ; CASTRO, B. P. S. ; VALENTIM, R. A. M. . Kit Educacional para Controle e Supervisão Aplicado a Nível. Holos, Natal, v. 2, p. 68-72, 2009

Análise do licenciamento ambiental como instrumento de política do meio ambiente no Rio Grande do Norte Período 1992-2003

This analysis on the ambient licensing is based on a research that identifies the fragilities and advances of the application of this instrument of politics of the environment in the ambient politics of the Rio Grande do Norte, in the period of 1992 the 2003. The isolated urban area of Búzios, situated in the City of Nísia Floresta/RN, situated in the eastern coast of the State, where concentrates the boarding of the ambient question as a matter in the Brazilian process of urbanization, over all the institutionalization and implementation of the ambient licensing. They are distinguished in the used methodology in consultation to the diverse involved social segments with the ambient subject in study, the example of the managers, technician and specialists, as well as the application of the legislation and norms techniques, the forms of appropriation of the common wealth and the procedures of ambient licensing of the competent agencies. The results of the research designate that the ambient licensing while instrument of the ambient politics is one of the alternatives more efficient as techniques in the process of sustainable development, since it is beyond the prerogatives to conciliate the activities and enterprises with the conservation of the environmental resources and natural benefits to the societies. In the RN one evidenced progress in the ambient legislation and the instructions techniques, and that the imperfections and limitations in the system of ambient licensing are not directly on to the instruments, but in the implementation of mechanisms of the ambient agencies. This because they do not make use of operational structure to apply in practical and established abilities, as an ambient management, institutional joint and deliberations of the State Counselor for Environment

Projeto, construção e análise de um prototipo vibracional em escala de bancada aplicável ao tratamento de água de produção de petróleo bruto, mediante inovadora operação híbrida de adsorção e auto-flotação

A self-flotator vibrational prototype electromechanical drive for treatment of oil and water emulsion or like emulsion is presented and evaluated. Oil production and refining to obtain derivatives is carried out under arrangements technically referred to as on-shore and off-shore, ie, on the continent and in the sea. In Brazil 80 % of the petroleum production is taken at sea and area of deployment and it cost scale are worrisome. It is associated, oily water production on a large scale, carrier 95% of the potential pollutant of activity whose final destination is the environment medium, terrestrial or maritime. Although diversified set of techniques and water treatment systems are in use or research, we propose an innovative system that operates in a sustainable way without chemical additives, for the good of the ecosystem. Labyrinth adsor-bent is used in metal spirals, and laboratory scale flow. Equipment and process patents are claimed. Treatments were performed at different flow rates and bands often monitored with control systems, some built, other bought for this purpose. Measurements of the levels of oil and grease (OGC) of efluents treaty remained within the range of legal framework under test conditions. Adsorbents were weighed before and after treatment for obtaining oil impregna-tion, the performance goal of vibratory action and treatment as a whole. Treatment technolo-gies in course are referenced, to compare performance, qualitatively and quantitatively. The vibration energy consumption is faced with and without conventional flotation and self-flotation. There are good prospects for the proposed, especially in reducing the residence time, by capillary action system. The impregnation dimensionless parameter was created and confronted with consecrated dimensionless parameters, on the vibrational version, such as Weber number and Froude number in quadratic form, referred to as vibrational criticality. Re-sults suggest limits to the vibration intensity

Segurança da informação no correio eletrônico com base na ISO/IEC 17799 :um estudo de caso em uma instituição superior com foco no treinamento

The electronic mail service is one of the most Internet services that grow in the corporate environment. This evolution is bringing several problems for the organizations, especially to information that circulates inside of the corporate net. The lack of correct orientation to the people, about the usage and the security importance of these resources, is leaving breaches and causing misusage and overuse of service, for example. In recent literature, it starts to coming out several ideas, which has helped to rganizations how to plain and how to implement the information security system to the electronic mail in computer environment. However, these ideas are still not placed in practice in many companies, public or private. This dissertation tries to demonstrate the results of a research that has like goal, identify the importance that user training has over the information security policy, through a case study inside of private superior education institute in this state. Besides, this work had by basic orientation the ISO/IEC 17799, which talk about People Security. This study was developed over a proposed model to this research, which looked for offer conditions to guide the institution studied, how to plan better a information security policy to the electronic mail. Also, this research has an exploratory and descreptive nature and your type, qualitative. Firstly, it was applied na questionary to the information technology manager, as better way to get some general data and to deepen the contact which still then, it was being kept through e-mail. Thereupon this first contact, eleven interviews were done with the same manager, beside one interview with twenty-four users, among employees e students. After that to collect and transcript the interviews, were review with the manager all informations given, to correct any mistakes and to update that informations, to then, start the data analyze. The research suggests that the institution has a pro attitude about the information security policy and the electronic mail usage. However, it was clear that answers have their perception about information security under a very inexperient way, derived of a planning lack in relation to training program capable to solve the problem