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Optimization Tool (optimization + tool)
Selected AbstractsShort-term scheduling of a wind generation and hydrogen storage in the electricity marketEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 5 2010G. Tina Abstract Intermittent renewable energy sources (RES) are promising to be the future of electricity generation. In particular wind generation, owing to its stochastic behaviour, has to be carefully managed. Its lack of sufficient predictability decreases the energy value in the current framework of electrical markets, therefore, beyond a certain threshold; this kind of generation into the electrical system represents a problem for the transmission system operator (TSO) during its despatching service. The coupling of wind energy conversion system (WECS) with a storage medium (i.e. hydrogen) could improve the programmability of such generation plants in electrical markets. In this paper, an economical optimization tool has been developed in order to find the short-term scheduling so as to maximize the economic revenues in the day-ahead electricity market of a storage plant coupled with a wind farm. This tool needs as input the forecasts of both wind generation power and market prices, obtained with the adoption of pre-processing input data algorithm based on different methods that involve both statistical and probabilistic approaches. Copyright © 2009 John Wiley & Sons, Ltd. [source] An improved weighting method with multibounds formulation and convex programming for multicriteria structural optimizationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 9 2001W. H. Zhang Abstract This paper presents an improved weighting method for multicriteria structural optimization. By introducing artificial design variables, here called as multibounds formulation (MBF), we demonstrate mathematically that the weighting combination of criteria can be transformed into a simplified problem with a linear objective function. This is a unified formulation for one criterion and multicriteria problems. Due to the uncoupling of involved criteria after the transformation, the extension and the adaptation of monotonic approximation-based convex programming methods such as the convex linearization (CONLIN) or the method of moving asymptotes (MMA) are made possible to solve multicriteria problems as efficiently as for one criterion problems. In this work, a multicriteria optimization tool is developed by integrating the multibounds formulation with the CONLIN optimizer and the ABAQUS finite element analysis system. Some numerical examples are taken into account to show the efficiency of this approach. Copyright © 2001 John Wiley & Sons, Ltd. [source] CFD-based optimization of aerofoils using radial basis functions for domain element parameterization and mesh deformationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 8 2008A. M. Morris Abstract A novel domain element shape parameterization method is presented for computational fluid dynamics-based shape optimization. The method is to achieve two aims: (1) provide a generic ,wrap-around' optimization tool that is independent of both flow solver and grid generation package and (2) provide a method that allows high-fidelity aerodynamic optimization of two- and three-dimensional bodies with a low number of design variables. The parameterization technique uses radial basis functions to transfer domain element movements into deformations of the design surface and corresponding aerodynamic mesh, thus allowing total independence from the grid generation package (structured or unstructured). Independence from the flow solver (either inviscid, viscous, aeroelastic) is achieved by obtaining sensitivity information for an advanced gradient-based optimizer (feasible sequential quadratic programming) by finite-differences. Results are presented for two-dimensional aerofoil inverse design and drag optimization problems. Inverse design results demonstrate that a large proportion of the design space is feasible with a relatively low number of design variables using the domain element parameterization. Heavily constrained (in lift, volume, and moment) two-dimensional aerofoil drag optimization has shown that significant improvements over existing designs can be achieved using this method, through the use of various objective functions. Copyright © 2008 John Wiley & Sons, Ltd. [source] One-zone simulation model of an oil-injected screw chillerINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 15 2004C. V. Le Abstract This paper presents a one-zone steady-state system model of an oil-injected screw chiller. The model can be used as a design and optimization tool for system performance of multiple-chiller plant in process industries. All major components of the system are modelled in a modular format including the oil-injected screw compressor, shell and tube condenser, flooded evaporator and a high side-float value. The model results are validated with the experimental data from a multiple-chiller plant at a process industry. The validated results show that the part-load ratio and the glycol,water temperature at the evaporator inlet significantly affect the system performance as compared to the temperature of cooling water entering the condenser. Copyright © 2004 John Wiley & Sons, Ltd. [source] A practical approach for estimating illumination distribution from shadows using a single imageINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 2 2005Taeone Kim Abstract This article presents a practical method that estimates illumination distribution from shadows using only a single image. The shadows are assumed to be cast on a textured, Lambertian surface by an object of known shape. Previous methods for illumination estimation from shadows usually require that the reflectance property of the surface on which shadows are cast be constant or uniform, or need an additional image to cancel out the effects of varying albedo of the textured surface on illumination estimation. But, our method deals with an estimation problem for which surface albedo information is not available. In this case, the estimation problem corresponds to an underdetermined one. We show that the combination of regularization by correlation and some user-specified information can be a practical method for solving the underdetermined problem. In addition, as an optimization tool for solving the problem, we develop a constrained Non-Negative Quadratic Programming (NNQP) technique into which not only regularization but also multiple linear constraints induced by user-specified information are easily incorporated. We test and validate our method on both synthetic and real images and present some experimental results. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 143,154, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20047 [source] A new approach to solving problems of multi-state system reliability optimizationQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 2 2001Gregory Levitin Abstract Usually engineers try to achieve the required reliability level with minimal cost. The problem of total investment cost minimization, subject to reliability constraints, is well known as the reliability optimization problem. When applied to multi-state systems (MSS), the system has many performance levels, and reliability is considered as a measure of the ability of the system to meet the demand (required performance). In this case, the outage effect will be essentially different for units with different performance rate. Therefore, the performance of system components, as well as the demand, should be taken into account. In this paper, we present a technique for solving a family of MSS reliability optimization problems, such as structure optimization, optimal expansion, maintenance optimization and optimal multistage modernization. This technique combines a universal generating function (UGF) method used for fast reliability estimation of MSS and a genetic algorithm (GA) used as an optimization engine. The UGF method provides the ability to estimate relatively quickly different MSS reliability indices for series-parallel and bridge structures. It can be applied to MSS with different physical nature of system performance measure. The GA is a robust, universal optimization tool that uses only estimates of solution quality to determine the direction of search. Copyright © 2001 John Wiley & Sons, Ltd. [source] Application of the operating window concept to remediation-option selectionREMEDIATION, Issue 3 2004Duncan I. Scott An Erratum has been published for this article in Remediation 14(4) 2004, 141. The selection of remediation options for the management of unacceptable risks at contaminated sites is hindered by insufficient information on their performance under different site conditions. Therefore, there is a need to define "operating windows" for individual remediation options to summarize their performance under a variety of site conditions. The concept of the "operating window" has been applied as both a performance optimization tool and decision support tool in a number of different industries. Remediation-option operating windows could be used as decision support tools during the "options appraisal" stage of the Model Procedures (CLR 11), proposed by the Environment Agency (EA) for England and Wales, to enhance the identification of "feasible remediation options" for "relevant pollutant linkages." The development of remediation-option operating windows involves: 1) the determination of relationships between site conditions ("critical variables") and option performance parameters (e.g., contaminant degradation or removal rates) and 2) the identification of upper- and lower-limit values ("operational limits") for these variables that define the ranges of site conditions over which option performance is likely to be sufficient (the "operating window") and insufficient (the "operating wall") for managing risk. Some research has used case study data to determine relationships between critical variables and subsurface natural attenuation (NA) process rates. Despite the various challenges associated with the approach, these studies suggest that available case study data can be used to develop operating windows for monitored natural attenuation (MNA) and, indeed, other remediation options. It is envisaged that the development of remediation-option operating windows will encourage the application of more innovative remediation options as opposed to excavation and disposal to landfill and/or on-site containment, which remain the most commonly employed options in many countries. © 2004 Wiley Periodicals, Inc. [source] Material Flow Networks as a Means of Optimizing Production SystemsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 4 2010H. Lambrecht Abstract Material flow networks are a specific technique for material flow analysis. Software tools based on this method have been used by many companies to analyze and improve complex production systems. While their intuitive modeling approach strongly enhances the identification of optimization potentials, automatic model optimization is not yet possible. The KOMSA project has closed this important methodological and instrumental gap. This article presents the developed prototype of a material flow-based optimization tool. We provide numerical results on the convergence of the implemented optimization algorithms. The added value of integrating optimization with material flow analysis is illustrated by applying the software tool to a real optimization problem from the waste industry. [source] | |||||||||||||||||||