Navegando por Assunto "Fuzzy systems"

Agora exibindo 1 - 3 de 3

Acesso aberto (Open Access)
Desenvolvimento a eventos discretos de um controlador de balanceamento de fases para sistemas legados de baixa tensão e microgrids
(Universidade Federal do Pará, 2019-06-10) VILCHEZ, José Ruben Sicchar; SILVA, José Reinaldo; http://lattes.cnpq.br/9317869378701106; COSTA JÚNIOR, Carlos Tavares da; http://lattes.cnpq.br/6328549183075122
In the up-grading of the legacy low-voltage system as urban microgrids, phase - balance algorithm development becomes useful and important to ensures robust and reliable load balancing, establish an efficient automation workflow among consumers, the legacy lowvoltage grid and the supervision center of the distribution network of electrical power. It constituting an alternative. This may constitute an alternative phase-balancing control system based on consumer units dynamic switching rather than electrical current injection by microgrids. Formal automation design of these algorithms become an interesting milestone for performance evaluation and properties validation for their insertion in the new microgrid architecture. This may evaluate the system's reliable performance when verifying dynamic properties as well as, the univocal solutions that ensure load transfer and load stability robustness of low-voltage grid, without operation interruptions neither conflicting events. This work, proposes a new phase-load- balancing control system based on combined algorithms resulting from a Hierarchical Petri net system design. Through this model it was obtained an optimized and reliable automated workflow of load balance in the low-voltage grid phases, with an efficient choice of consumer units for the switching process, aiming to obtain a robust steady state of load against unbalances between phases, and neutral current minimized. From the model obtained called “Transformer- Phase Balancing Controller” (T-PBC) were developed four integrated algorithms: the Load Transfer Algorithm, that calculates the load imbalance level and power to be transferred in the transformer phases; the Consumption Diagnose Algorithm, that identifies the load levels margins in each consumer unit; the Consumption Forecast Algorithm, that forecast the monthly energy future states in consumers; and the Switch Selection Algorithm, that selects the consumers units to switch based on the future state of energy consumption, the load level margins and the average of the energy future states. Based on the performance results, it was obtained, the efficient reduction of the neutral current and the load average unbalance in the low-voltage grid phases, with load stability robustness about three months, making it an efficient alternative system against load unbalances in the legacy low-voltage grid and the microgrids.
Acesso aberto (Open Access)
Mecanismo de roteamento cross-layer em redes móveis Ad Hoc sem fio: um modelo de inteligência computacional com eficiência energética e suporte a mobilidade e QoE
(Universidade Federal do Pará, 2016-03-18) CARVALHO, Tássio Costa de; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567
The evolution of wireless communications technologies has led to the need to provide network support for data and video applications and thus promote the development of new types of network configurations adapted to these new requirements. MANET is an important type of operation networks that employs mechanisms that can enable dynamic autoconfiguration, which requires a higher efficiency of its routing protocols. These protocols can also be challenged due to energy failures that are becoming increasingly severe in relation to the common networks failure; furthermore, the quality of the multimedia stream corresponds to a fundamental premise to the next generation wireless networks and the future Internet. This thesis proposes a new routing mechanism based on cross-layer paradigm to enhance the main routing protocols, by inserting new metrics in a computational intelligence decision making based on fuzzy systems, providing energy efficiency, support to manage mobility and quality experience to the devices, choosing the best route for the flow of computer networks. The proposal is evaluated in network simulator, demonstrating its efficiency through network results, quality of experience metrics and maximizing the communication’s lifetime.
Acesso aberto (Open Access)
Modelagem Neuro-Fuzzy de perdas de propagação para planejamento de redes LTE
(Universidade Federal do Pará, 2016-05-06) NASCIMENTO, Regina de Nasaré Almeida do; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
The development of mobile communication technologies is associated to the demand of services by users who are more and more using the data services than voice. And to keep up with those demands the telecommunication enterprises seek to meet with new technologies this user searching for speed and quality in the service used by mobile networks. The technology LTE (Long Term Evolution) has shown flexible features that stand out in relation to the technologies that preceded it as the GSM and UMTS and the operators to meet the goals of existing networks such as multimedia services, spectral efficiency and business for mobile broadband. The organization that developed the LTE specifications is the 3GPP (3rd Generation Partners Project) and standardized by the European Standards Institute in the area of Telecommunications ETSI (European Telecommunications Standard Institute). This dissertation was realized a study about propagation losses in outdoor environment, from models found in the literature and suitable for the propagation channel. Performance results are presented using the metrics of root mean square error and standard deviation and the graphical representation of data measured. And to helpful to understand this analysis is interesting to map the area and deploy or adapt planning tools of coverage with more accurate and efficient. The data used in this study was collected on some main roads in the Castanhal city, of Pará state, northern Brazil. The frequency of the transmitted signal used for LTE is 1.800 MHz and the method used to predict propagation loss was Neuro-Fuzzy. This system uses the techniques of Computational Intelligence that combines Artificial Neural Networks (ANN) and Fuzzy Logic (LF) and have demonstrated ability to solve different types of problems in various applications in different areas. And through this technique, the comparison between the results predicted by the proposed method and literature propagation models to provide an analysis by the signal characteristics in specific channels, observing the limitations and local features.