A survey of control architectures for autonomous mobile robots

MEDEIROS, Adelardo A. D.A survey of control architectures for autonomous mobile robots. J. Braz. Comp. Soc., Campinas, v. 4, n. 3, abr. 1998 .Disponível em: Acesso: 27 set. 2010.

A survey of control architectures for autonomous mobile robots

MEDEIROS, Adelardo A. D.A survey of control architectures for autonomous mobile robots. J. Braz. Comp. Soc., Campinas, v. 4, n. 3, abr. 1998 .Disponível em: Acesso: 27 set. 2010.

Rede de controle em ambiente hospitalar: um protocolo multiciclos para automação hospitalar sobre IEEE 802.3 com IGMP Snooping

VALENTIM, R. A. M. ; MORAIS, A. H. F. ; SOUZA, V. S. V ; ARAUJO JUNIOR, H. B. ; BRANDAO, G. B. ; GUERREIRO, A. M. G. . Rede de Controle em Ambiente Hospitalar: um protocolo multiciclos para automação hospitalar sobre IEEE 802.3 com IGMP Snooping. Revista Ciência e Tecnologia, v. 11, p. 19, 2009

Fatores influenciadores da implementação de ações de gestão de segurança da informação :um estudo com executivos e gerentes de tecnologia da informação das empresas do Rio Grande do Norte

Information is one of the most valuable organization s assets, mainly on a global and highly competitive world. On this scenery there are two antagonists forces: on one side, organizations struggle for keeping protected its information, specially those considered as strategic, on the other side, the invaders, leaded by innumerous reasons - such as hobby, challenge or one single protest with the intention of capturing and corrupting the information of other organizations. This thesis presents the descriptive results of one research that had as its main objective to identify which variables influence the Executives´ and CIOs´ perceptions toward Information Security. In addition, the research also identified the profile of Rio Grande do Norte s organizations and its Executives/CIOs concerning Information Security, computed the level of agreement of the respondents according to NBR ISO/IEC 17799 (Information technology Code of practice for information security management) on its dimension Access Control. The research was based on a model, which took into account the following variables: origin of the organization s capital, sector of production, number of PCs networked, number of employees with rights to network, number of attacks suffered by the organizations, respondent´s positions, education level, literacy on Information Technology and specific training on network. In the goal´s point of view, the research was classified as exploratory and descriptive, and, in relation of the approach, quantitative. One questionnaire was applied on 33 Executives and CIOs of the 50 Rio Grande do Norte s organizations that collected the highest taxes of ICMS - Imposto sobre Circulação de Mercadorias on 2000. After the data collecting, cluster analysis and chi-square statistical tools were used for data analysis. The research made clear that the Executives and CIOs of Rio Grande do Norte s organizations have low level of agreement concerning the rules of the NBR ISO/IEC 17799. It also made evident that the Executives and CIOs have its perception toward Information Security influenced by the number of PCs networked and by the number of attacks suffered by the organizations

Group Sequential Communication (GSC): Especificação e Análise de Desempenho de umMecanismo de Comunicação de Tempo Real Compatível ao Padrão IEEE 802.11/11e Aplicado à Automação Industrial

This thesis proposes the specification and performance analysis of a real-time communication mechanism for IEEE 802.11/11e standard. This approach is called Group Sequential Communication (GSC). The GSC has a better performance for dealing with small data packets when compared to the HCCA mechanism by adopting a decentralized medium access control using a publish/subscribe communication scheme. The main objective of the thesis is the HCCA overhead reduction of the Polling, ACK and QoS Null frames exchanged between the Hybrid Coordinator and the polled stations. The GSC eliminates the polling scheme used by HCCA scheduling algorithm by using a Virtual Token Passing procedure among members of the real-time group to whom a high-priority and sequential access to communication medium is granted. In order to improve the reliability of the mechanism proposed into a noisy channel, it is presented an error recovery scheme called second chance algorithm. This scheme is based on block acknowledgment strategy where there is a possibility of retransmitting when missing real-time messages. Thus, the GSC mechanism maintains the real-time traffic across many IEEE 802.11/11e devices, optimized bandwidth usage and minimal delay variation for data packets in the wireless network. For validation purpose of the communication scheme, the GSC and HCCA mechanisms have been implemented in network simulation software developed in C/C++ and their performance results were compared. The experiments show the efficiency of the GSC mechanism, especially in industrial communication scenarios.

Desenvolvimento de um software de comunicação sem fio aplicado à instrumentação de unidade de elevação de petróleo tipo Plunger Lift

This dissertation aims to develop a software applied to a communication system for a wireless sensor network (WSN) for tracking analog and digital variables and control valve of the gas flow in artificial oil s elevation units, Plunger Lift type. The reason for this implementation is due to the fact that, in the studied plant configuration, the sensors communicate with the PLC (Programmable and Logic Controller) by the cables and pipelines, making any changes in that system, such as changing the layout of it, as well as inconveniences that arise from the nature of the site, such as the vicinity s animals presence that tend to destroy the cables for interconnection of sensors to the PLC. For software development, was used communication polling method via SMAC protocol (Simple Medium Access ControlIEEE 802.15.4 standard) in the CodeWarrior environment to which generated a firmware, loaded into the WSN s transceivers, present in the kit MC13193-EVK, (all items described above are owners of Freescale Semiconductors Inc.). The network monitoring and parameterization used in its application, was developed in LabVIEW software from National Instruments. The results were obtained through the observation of the network s behavior of sensors proposal, focusing on aspects such as: indoor and outdoor quantity of packages received and lost, general aspects of reliability in data transmission, coexistence with other types of wireless networks and power consumption under different operating conditions. The results were considered satisfactory, which showed the software efficiency in this communication system

Um serviço de certificação digital para plataformas de middleware

Nowadays due to the security vulnerability of distributed systems, it is needed mechanisms to guarantee the security requirements of distributed objects communications. Middleware Platforms component integration platforms provide security functions that typically offer services for auditing, for guarantee messages protection, authentication, and access control. In order to support these functions, middleware platforms use digital certificates that are provided and managed by external entities. However, most middleware platforms do not define requirements to get, to maintain, to validate and to delegate digital certificates. In addition, most digital certification systems use X.509 certificates that are complex and have a lot of attributes. In order to address these problems, this work proposes a digital certification generic service for middleware platforms. This service provides flexibility via the joint use of public key certificates, to implement the authentication function, and attributes certificates to the authorization function. It also supports delegation. Certificate based access control is transparent for objects. The proposed service defines the digital certificate format, the store and retrieval system, certificate validation and support for delegation. In order to validate the proposed architecture, this work presents the implementation of the digital certification service for the CORBA middleware platform and a case study that illustrates the service functionalities

Comitês de Classificadores para o Reconhecimento Multibiométrico em Dados Biométricos Revogáveis

This work discusses the application of techniques of ensembles in multimodal recognition systems development in revocable biometrics. Biometric systems are the future identification techniques and user access control and a proof of this is the constant increases of such systems in current society. However, there is still much advancement to be developed, mainly with regard to the accuracy, security and processing time of such systems. In the search for developing more efficient techniques, the multimodal systems and the use of revocable biometrics are promising, and can model many of the problems involved in traditional biometric recognition. A multimodal system is characterized by combining different techniques of biometric security and overcome many limitations, how: failures in the extraction or processing the dataset. Among the various possibilities to develop a multimodal system, the use of ensembles is a subject quite promising, motivated by performance and flexibility that they are demonstrating over the years, in its many applications. Givin emphasis in relation to safety, one of the biggest problems found is that the biometrics is permanently related with the user and the fact of cannot be changed if compromised. However, this problem has been solved by techniques known as revocable biometrics, which consists of applying a transformation on the biometric data in order to protect the unique characteristics, making its cancellation and replacement. In order to contribute to this important subject, this work compares the performance of individual classifiers methods, as well as the set of classifiers, in the context of the original data and the biometric space transformed by different functions. Another factor to be highlighted is the use of Genetic Algorithms (GA) in different parts of the systems, seeking to further maximize their eficiency. One of the motivations of this development is to evaluate the gain that maximized ensembles systems by different GA can bring to the data in the transformed space. Another relevant factor is to generate revocable systems even more eficient by combining two or more functions of transformations, demonstrating that is possible to extract information of a similar standard through applying different transformation functions. With all this, it is clear the importance of revocable biometrics, ensembles and GA in the development of more eficient biometric systems, something that is increasingly important in the present day

Rede de controle em ambiente hospitalar: um protocolo multiciclos para automação hospitalar sobre IEEE 802.3 com IGMP Snooping

VALENTIM, R. A. M. ; MORAIS, A. H. F. ; SOUZA, V. S. V ; ARAUJO JUNIOR, H. B. ; BRANDAO, G. B. ; GUERREIRO, A. M. G. . Rede de Controle em Ambiente Hospitalar: um protocolo multiciclos para automação hospitalar sobre IEEE 802.3 com IGMP Snooping. Revista Ciência e Tecnologia, v. 11, p. 19, 2009