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Öğe A Hopfield neural network approach to the dual response problem(JOHN WILEY & SONS LTD, 2005) Koksoy, O; Yalcinoz, TThe application of neural networks to optimization problems has been an active research area since the early 1980s. Unconstrained optimization, constrained optimization and combinatorial optimization problems have been solved using neural networks. This study presents a new approach using Hopfield neural networks (HNNs) for solving the dual response system (DRS) problems. The major aim of the proposed method is to produce a string of solutions, rather than a 'one-shot' optimum solution, to make the trade-offs available between the mean and standard deviation responses. This gives more flexibility to the decision-maker in exploring alternative solutions. The proposed method has been tested on two examples. The HNN results are very close to those obtained by using the NIMBUS (Nondifferentiable Interactive Multiobjective Bundle-based Optimization System) algorithm. Choosing an appropriate solution method for a certain multi-objective optimization problem is not easy, as has been made abundantly clear. Unlike the NIMBUS method, the HNN approach does not set any specific assumptions on the behaviour or the preference structure of the decision maker. As a result, the proposed method will still work and generate alternative solutions whether or not the decision maker has enough time and capabilities for co-operation. Copyright (c) 2005 John Wiley & Sons, Ltd.Öğe A new algorithm and computation approach for economic dispatch with prohibited operating zones in power systems(MULTI SCIENCE PUBL CO LTD, 2005) Cetinkaya, N; Urkmez, A; Erkmen, I; Yalcinoz, TThis paper presents a new algorithm and computation approach to solve the economic load dispatch (ELD) in electrical power systems. We applied a new power formula to solve the LLD problem. If production units cost Curves are represented property then ELD becomes More Correct. In this respect we assumed that production units have prohibited operating zones. Cost curves of the production units are generally accepted as piece-wise quadratic function. The power production is cheaper since we do not use the production units ill the prohibited operating zones. The proposed method and algorithm are compared to other ELD methods oil the standard test systems. The proposed method solve the dispatch problem faster than the other ELD methods.Öğe A new genetic algorithm with arithmetic crossover to economic and a environmental economic dispatch(C R L PUBLISHING LTD, 2005) Yalcinoz, T; Altun, HThis paper presents a new genetic approach based on arithmetic crossover for solving the economic dispatch and environmentally constrained economic dispatch problems. Elitism, arithmetic crossover and mutation are used in the genetic algorithm to generate successive sets of possible operating policies. The proposed technique improves the quality of the solution. The employed arithmetic crossover operation takes the real values presented by two individuals and produced new generation on the basis of the arithmetic mean. For economic dispatch problem, the new genetic approach is compared with an improved Hopfield NN approach (IHN) [1], a fuzzy logic controlled genetic algorithm (FLCGA) [2], an advance engineered-conditioning genetic approach (AECGA) [3] and an advance Hopfield NN approach (AHNN) [4]. The results of the proposed approach for environmentally economic dispatch are compared with the results of the Taboo Search (TS) [5], the Hopfield NN [5] and a neural networks approach [6].Öğe An educational software package for power systems analysis and operation(MANCHESTER UNIV PRESS, 2005) Yalcinoz, TThis paper presents a software package developed in Matlab for teaching power systems analysis and operation. The software package is used to support and enhance power engineering education at both undergraduate and postgraduate levels. The application programs in this package include fault analysis, load flow analysis, transient stability, economic dispatch, unit commitment and load forecasting. All modules of the package are independent of each other. The students or researchers can make copies of the software to study and can modify any module of the package.Öğe Comparison of fuzzy logic and PID controllers for TCSC using Matlab(UNIV WEST ENGLAND-UWE, 2005) Yolac, U; Yalcinoz, TIn this paper, a Fuzzy logic controller and a PID controller are used to control firing angles of TCSC using Matlab Simulink, Power System Blockset and Fuzzy Logic Toolbox. The graphic interface of Simulink provides a user-friendly environment where the power circuit and control system are represented in the same diagram. The design and testing of TCSC are verified using the Matlab environment. The studied power system is a simple two buses system with distributed parameter line. The simulation results show that the fuzzy logic controller can generate beter dynamic response.Öğe Constrained economic dispatch with prohibited operating zones: A Hopfield neural network approach(IEEE, 2000) Yalcinoz, T; Altun, H; Hasan, U; Economides, C; Pattichis, CS; Maliotis, G; Papaconstantinou, M; Michaelides, N; Schizas, CNThe work explores the use of Hopfield neural network for a constrained economic dispatch problem with prohibited operating zones. Yalcinoz and Short [1] discussed a special methodology to improve the performance of Hopfield networks for solving the unconstrained economic dispatch problem. In this paper the improved Hopfield network is applied to the constrained economic dispatch problem. A new mapping process has been used and a computational method for obtaining the weights and biases is described using a slack variable technique for handling inequality constraints. Applying the proposed approach is demonstrated by a 15-unit system with 4 units having prohibited zones.Öğe Discussion of "New approach with a Hopfield modeling framework to economic dispatch"(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2000) Yalcinoz, T[Abstract Not Available]Öğe Environmentally constrained economic dispatch via a genetic algorithm with arithmetic crossover(IEEE, 2002) Yalcinoz, T; Altun, HFor electric power generation and dispatching problems, absolute minimum cost is not any more the only criterion to be met. Environmental considerations have become one of the major management concerns. The environmentally constrained economic dispatch problem can be classified as a multi-objective optimization and non-linear programming problem. This paper proposes a solution for environmental economic dispatch problem using modified GA which based on arithmetic crossover operator. The employed arithmetic crossover operation takes the real values presented by two individuals and produced new generation on the basis of the arithmetic mean. Numerical results for two case studies have been presented to illustrate the performance and applicability of the proposed method.Öğe Hopfield neural network approaches to economic dispatch problems(ELSEVIER SCI LTD, 2001) Yalcinoz, T; Cory, BJ; Short, MJThis paper aims to identify and investigate a new Hopfield neural network structure suitable for application to economic dispatch problems such as unconstrained economic dispatch, economic dispatch with transmission capacity constraints and multi-area economic dispatch. A new mapping technique is described for quadratic programming problems with equality and inequality constraints. Side constraints are handled by a modified activation function. The proposed method is tested on different sizes of systems having between 3 and 240 generating units. The results of the proposed method are compared with those of a classical method and the improved Hopfield NN approach (IEE Proc Gen Transm Distrib 144(2) (1997) 181). (C) 2001 Elsevier Science Ltd. All rights reserved.Öğe Mean square error criteria to multiresponse process optimization by a new genetic algorithm(ELSEVIER SCIENCE INC, 2006) Koksoy, O; Yalcinoz, TThe recent push for quality in industry has brought response surface methodology to the attention of many users. Most of the published literature on robust design methodology is basically concerned with optimization of a single response or quality characteristic which is often most critical to consumers. For most products, however, quality is multidimensional, so it is common to observe multiple responses in an experimental situation. In this paper, we present a methodology for analyzing several quality characteristics simultaneously using the mean square error (MSE) criterion when data are collected from a combined array. Problems with highly nonlinear, or multimodal, objective functions are extremely difficult to solve and are further complicated by the presence of multiple objectives. An alternative approach is to use a heuristic search procedure such as a genetic algorithm (GA). The GA generates a string of solutions using genetics-like operators such as selection, crossover and mutation. In this paper, a genetic algorithm based on arithmetic crossover for the multiresponse problem is proposed. The string of solutions highlight the trade-offs that one needs to consider in order to obtain a compromise solution. A numerical example has been presented to illustrate the performance and the applicability of the proposed method. (c) 2005 Elsevier Inc. All rights reserved.Öğe Neural learning for articulatory speech synthesis under different statistical characteristics of acoustic input patterns(PERGAMON-ELSEVIER SCIENCE LTD, 2003) Altun, H; Curtis, KM; Yalcinoz, TInput data representation is highly decisive in neural learning in terms of convergence. In this paper, within an analytical and statistical framework, the effect of the distribution characteristics of the input pattern vectors on the performance of the back-propagation (BP) algorithm is established for a function approximation problem, where parameters of an articulatory speech synthesizer are estimated from acoustic input data. The aim is to determine the optimum statistical characteristics of the acoustic input patterns in order to improve neural learning. Improvement is obtained through a modification of the statistical characteristics of the input data, which reduces effectively the occurrence of node saturation in the hidden layer. (C) 2002 Elsevier Science Ltd. All rights reserved.Öğe Security dispatch using the Hopfield neural network(IEE-INST ELEC ENG, 1999) Yalcinoz, T; Short, MJ; Cory, BJA restructuring of the improved Hopfield neural network (NN) approach, which has previously been proposed for solving economic dispatch, is proposed for solving real time economic dispatch problem with security constraints. A new mapping process is formulated and a computational method for obtaining the weights and biases is described using a slack variable technique for handling inequality constraints. Side constraints are handled by a modified activation function for which a symmetric ramp function is chosen for the input-output function and applied to each element of the variable set. The Hopfield NN approach is tested on the IEEE 30-bus system for different demands.Öğe Short term and medium term power distribution load forecasting by neural networks(PERGAMON-ELSEVIER SCIENCE LTD, 2005) Yalcinoz, T; Eminoglu, ULoad forecasting is an important subject for power distribution systems and has been studied from different points of view. In general, load forecasts should be performed over a broad spectrum of time intervals, which could be classified into short term, medium term and long term forecasts. Several research groups have proposed various techniques for either short term load forecasting or medium term load forecasting or long term load forecasting. This paper presents a neural network (NN) model for short term peak load forecasting, short term total load forecasting and medium term monthly load forecasting in power distribution systems. The NN is used to learn the relationships among past, current and future temperatures and loads. The neural network was trained to recognize the peak load of the day, total load of the day and monthly electricity consumption. The suitability of the proposed approach is illustrated through an application to real load shapes from the Turkish Electricity Distribution Corporation (TEDAS) in Nigde. The data represents the daily and monthly electricity consumption in Nigde, Turkey. (C) 2004 Elsevier Ltd. All rights reserved.
