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Decision support systems (DSS) are human-centered information systems meant to help managers placed on different authority levels to make more efficient and effective decisions for problems evincing an imperfect structure. These systems are very suitable information tools to apply to various management and control problems that are complex and complicated at the same time. Several issues concerning...
The paper introduces a fuzzy system meant to control the oxygen pressure and amperage of a CNC metal plate cutting machine. The fuzzy system control the oxygen pressure and the amperage by analyzing the plate thickness and type, which eliminates the possible human error in making such decision. The system was implemented using as hardware a Simatic S7-\300 PLC.
This paper discusses signal processing aspects concerning the iterative experiment-based improvement of the performance of crane mode control systems of inverted pendulum systems. The control system performance specifications are imposed in terms of a reference model, and the objective is to force the output error defined as the difference between the cart position as controlled output and the model...
The paper establishes a preliminary pragmatic method to obtain the control strategy of an innovative small windgenerator prototype. There is presented the proposed structure of the considered wind energy conversion system, respectively its components and subsystems. There were considered the wind turbine, the generator, the electronic converters, the brake systems and their characteristics, being...
The paper presents some considerations regarding the problematic of asynchronous generator's (AG) excitation. There are presented some theoretical considerations regarding the efficiency of the capacitive excited asynchronous generator compounding regarding the load voltage variation compensation. There is presented the determination of the compounding condenser's capacity by using the graph-analytical...
This paper presents considerations of using wireless sensor networks for monitoring conditions within wind farms, taking into considerations the specific of such applications. In these scenarios, which are intended to cover a lot of ground or even operate in difficult radio environments with strong attenuation, the simple and direct communication between source and destination is not always possible,...
This paper presents a self-tuning adaptive control structure designed through the minimization of a criteria function. It is described the computation methodology of the control law, being particularized for the case of a dual winding induction generator's excitation control. The parameter's estimator, integrated into the control system, is based on the on-line least mean square error algorithm. In...
The paper presents a study for implementing a brake sequence for a small wind generator for regimes that exceeds the rated values. Considering data from a real wind generator, two scenarios are presented: first, during a strong wind gust both the electrical and the mechanical brakes are coupled and, for the second case, a fault in the permanent magnet synchronous generator (PMSG) is caused. This study...
There were conceived original methods that intend to optimize (maximize) the efficiency of variable speed fixed blade wind generators. These methods are based on mathematical models of fixed blades wind turbines windmills. This is the main reason that an important part of the paper is dedicated to the problematic of mathematical modeling of the wind turbine - focused mainly on the determination from...
This paper provides a modeling of the phenomenon of solidification and cooling of continuously cast semi-finished, based on the finite difference method. Also, to validate the model and conducted a simulation with “Tirsim” program. In the process of continuous casting, the melting pot is passed, through the intermediary of the distributor, in the water-cooled crystallizer tank. In this way, a crust...
The paper presents a control strategy for a wind energy conversion system (WECS) for an optimal extraction of power from the wind. The topology of the system consists of a permanent magnet synchronous generator (PMSG), a diode bridge rectifier, a hybrid dc-dc converter which lowers the dc voltage, a supercapacitor and an inverter. However, the grid side inverter is not subject to this paper research...
Illumination and view dependent texture provide ample information on the appearance of real materials at the cost of enormous data storage requirements. Hence, past research focused mainly on compression and modelling of these data, however, few papers have explicitly addressed the way in which humans perceive these compressed data. We analyzed human gaze information to determine appropriate texture...
This paper presents the implementation of a neural network-based fault detection for wireless sensor networks (WSNs). There are discussed two proposed approaches: both a centralized and respectively distributed fault detection. The methods are validated using a wireless sensor network that takes environmental measurements every 60 seconds. There were considered various fault scenarios that were detected...
The paper presents some issues regarding an online tuning procedure for a recursive last mean square (RLMS) parameter estimator embedded into an adaptive controller used to control the terminal voltage of a synchronous generator. The analysis is mainly focused on the problematic regarding the reinitialization of the covariance matrix within the RLMS algorithm. A study case for a dynamical model, with...
In this paper a soft-starter model and its control strategy for connecting solutions to the grid of different operation modes for a wind turbine generator of 2/0.5 MW are evaluated. The thyristors switching for different functions of the firing angle are discussed. A complete simulation model of a constant speed wind turbine with cage rotor and double stator windings induction generator is also presented...
The paper proposes Markov models for the reliability analysis of the wireless sensor networks with standby backup elements. There are presented the theoretical aspects and some of the variables that are used in the domain of fault tolerant systems. There has been conducted a study regarding the reliability of system versus cost price, considering different number of hot redundant spare parts. Reliability...
The paper proposes Markov models for the reliability analysis of the wireless sensor networks. There are presented the theoretical aspects and some of the variables that are used in the domain of fault tolerant systems. There is also presented a comparison between systems using dedicated replacements and universal replacements for defective nodes. There has been conducted a study regarding the reliability...
In some cases of software-distributed applications, a large data amount must be accessed by a large number of users (dispersed geographically). In these cases, the database replication process provides an efficient solution to increase the application performances. This paper presents two methods to implement a multi-master database replication process. A replication example between two Oracle databases...
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