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In this paper a Wind Energy Conversion System based on Doubly Fed Induction Generator (DFIG) with an additional Series Grid Side Converter (SGSC) without transformer is proposed. Unbalanced stator voltages may be compensated by SGSC, thus eliminating unbalanced stator and rotor currents, active and reactive power oscillations, and shaft torque oscillations. Moreover, the control strategy of the proposed...
Localization is one of the main tasks of autonomous mobile robots. There are many approaches on how to determine the robot's position with reasonable precision, as with the use of sensor fusion (IMU, GPS, Image, LiDAR). Even though it is possible to achieve high precision with these sensors combined, a solution that requires less resources in terms of processing, energy consumption and yet provide...
This paper presents a multicriteria nominal classification method derived from the concepts of PROMETHEE, which is then applied to problems characterized by minimum performance profiles (MMP) to determine categories. In order to illustrate the applicability of the proposal, this method is applied to classify relational attitudes in the context of IT outsourcing regarding an IT service contractor company...
This paper presents a wireless intrusion prevention tool for distributed denial of service attacks DDoS. This tool, called Wireless Distributed IPS WIDIP, uses a different collection of data to identify attackers from inside a private network. WIDIP blocks attackers and also propagates its information to other wireless routers that run the IPS. This communication behavior provides higher fault tolerance...
Voice Activity Detection (VAD) plays an important role in current technological applications, such as wireless communications and speech recognition. In this paper, we address the VAD task through machine learning by using a discriminative restricted Boltzmann machine (DRBM). We extend the conventional DRBM to deal with continuous-valued data and employ feature vectors based either on mel-frequency...
In this work a numerical model related to an optical inclinometer is presented. This model is based on a fused fiber taper monitored in the transmitted power. Comparisons are made between the numerical and experimental results and it is demonstrated good agreement with them. Thus, the model is proven to be suitable to simulate variation of parameters in order to obtain better performance of the sensor...
Video streaming now amounts to the majority of traffic in the Internet. Media streaming relies on large-scale content distribution networks (CDNs), that incur significant costs to build or use. P2P distribution of video content reduce reliance on CDNs and costs. Unfortunately, P2P distribution is fraught with QoE problems, specially during flash crowds or in scenarios where users have limited bandwidth...
In this work, we propose a GRASP+VNS algorithm for solving the allocation of Roadside Units (RSUs) in a Vehicular Network. Our main objective is to find the minimum set of RSUs to meet a Deployment Delta (ρ1,ρ2). The Deployment Delta (ρ1,ρ2) is a metric for specifying minimal communication guarantees from the infrastructure supporting the Vehicular Network. We compare GRASP+VNS to some baseline algorithms:...
This paper describes an enhanced model for the Short Term Hydro Scheduling Problem, HSP, that includes the impact of operation decisions on the market prices and the possibility of adjusting the tailwater level and the generation and pumping efficiencies as a function of the flow. The solution approach uses an iterative procedure that solves in each iteration a linearized HSP problem using the linprog...
This paper describes an enhanced model for the Short Term Hydro Scheduling Problem, HSP, that includes the impact of operation decisions on the market prices and the possibility of adjusting the tailwater level. Additionally, the efficiency of hydraulic turbines is treated as a variable dependent on the discharged flows. The developed solution algorithm uses an iterative approach that solves in each...
Several researches have pointed the hybridization of metaheuristics as an effective way to deal with combinatorial optimization problems. Hybridization allows the combination of different techniques, exploiting the strengths and compensating the weakness of each of them. MAHM is a promising adaptive framework for hybridization of metaheuristics, originally designed for single objective problems. This...
With the advance of the Internet of Things (IoT), the interaction between humans and smart objects is already a reality. New applications that are expected to operate in dynamic environments must support different modes of human/machine interaction (e.g., voice and sign language), exhibit same or better performance in heterogeneous wireless and optical networks, and be able to react in real time....
In this demonstration, we explore the impact of optical-wireless network infrastructure when we vary the locus of computing for Internet of Things (IoT) services. Those services could involve devices ranging from low complexity sensors and actuators (e.g., smart light bulbs) to more advanced ones (e.g., multimedia sensors and smart glasses); in our experiment, we focus on the former. We design a smart...
Motor market is moving to IE3/Premium and IE4/Super-Premium efficiency classes and a significant effort is being made by motor manufacturers to increase the rated efficiency without increasing significantly manufacturing and materials cost. Moreover, since line-operated squirrel-cage induction motors can be started with electronic soft starters, their stator windings may be designed to operate in...
In this work we propose a new algorithm, Delta-r-GRASP, for solving the allocation of Roadside Units (RSUs) in a Vehicular Network. Our goal is to find the minimum set of RSUs to meet a Deployment Δρ2ρ1. The Deployment Δρ2ρ1 is a metric for specifying minimum communication guarantees from the infrastructure supporting the Vehicular Network. We compare our algorithm with a baseline algorithm, Delta-r...
Graphite Oxide (GO) was synthesized using the Improved Hummer's Method. After the successful synthesis of GO, it was characterized and its dielectric properties were investigated. The change of dielectric behavior of GO with exposure to chlorine gas (Cl2) was studied. The obtained data were then analyzed to determine the mechanism by which the dielectric properties change. It was established that...
Photovoltaic (PV) power plants are a form of renewable energy and their importance is increasing all around the world. In Brazil, the PV power plants connected to the grid are regulated through a credit compensation, in which the prosumer pays the difference between consumed and generated energy. Medium voltage consumers pay different prices for the energy consumed in peak load time and off-peak load...
This study focuses on the design and control of an 11.7 KW hybrid generation system using photovoltaic panels and a wind turbine. The conversion is accomplished by a multicell converter divided in two stages: the Generation Side Converter (GSC) and the Mains Side Converter (MSC). This paper will present the design of GSC highlighting the key components (wind turbine, photovoltaic cells, switching...
This study focuses on the grid connection of a 11.7kW hybrid generation system using photovoltaic panels and a wind turbine. The conversion is accomplished by a multicell converter divided in two stages: the Generation Side Converter (GSC) and the Mains Side Converter (MSC). This paper will present in detail the design of MSC highlighting the key components (LCL filter, the InterCell Transformer,...
The power system is experiencing an expansion of distributed generators connected to the low voltage network. In this context appears the so-called microgrid, which consists of a group of electrical microsources, loads and storage elements controlled as a single unit whose may operate either connected to or islanded from the main grid. The microgrid can be arranged in a centralized structure, e.g...
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