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Multiobjective consequent management of a contaminated network under pressure-deficient conditions

JOURNAL AMERICAN WATER WORKS ASSOCIATION 2014年第10期106卷 E470-E480页

作者： Afshar, Amin Marino, Miguel A. Univ Calif Davis Dept Civil & Environm Engn Davis CA 95616 USA

This article presents an integrated simulation optimization scheme for operational response management. It integrates a pressure-driven network solver (PDNS) with the multiobjective honey bee mating optimization (HBMO) algorithm. Solutions to the proposed multiobjective optimization problem generate a set of nondominated optimal operational strategies that minimizes consequences of intentional physical attacks on water infrastructure systems. Each trial solution developed by the optimizer defines a new network topology resulting from modified operation modes of nominated valves and hydrants. The PDNS finalizes the nodal pressure and modifies nodal withdrawal for the identified trial solution. Performance of the approach is illustrated using previously tested examples. Sensitivity of the optimal strategies to mathematical definition of the objective function is discussed.

关键词： optimization algorithms Simulation Topology Water supply

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Reliability-based maintenance scheduling of generating units in restructured power systems

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TURKISH JOURNAL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES 2014年第5期22卷 1147-1158页

作者： Fotuhi-Firuzabad, Mahmud Aminifar, Farrokh Shahzadeh, Abbas Sharif Univ Technol Dept Elect Engn Ctr Excellence Power Syst Management & Control Tehran Iran Univ Tehran Coll Engn Sch Elect & Comp Engn Tehran Iran Aryan Sanat Co Tehran Iran

Maintenance scheduling of generating units in restructured power systems is a collaborative and interactive process between independent system operators (ISOs) and generating companies (GENCOs). The ISO should comply with GENCO maintenance preferences subject to targeted system reliability levels. This process might be multistage since the admission of all initial unit outage requests may threaten system reliability. Hence, the ISO accepts some proposals and determines alternatives for the remaining units. The GENCOs are then allowed to confirm the alternatives or revise them. In this paper the ISO problem of generating unit maintenance scheduling is tackled. The objective function is to minimize the deviation of awarded schedule from the requested schedule, as measured in MW weeks. A novel and effective optimization technique is developed to solve the problem at hand. In the proposed methodology, risk leveling and dynamic programming optimization algorithms are concurrently utilized to lessen the computation burden and enhance the solution process. The effectiveness of the proposed method and its applicability to real-life systems are verified by examining the generation section of the IEEE reliability test system (IEEE-RTS). The performance of the new method is also compared with that of the individual risk leveling approach.

关键词： Dynamic programming maintenance scheduling optimization algorithms reliability assessment risk leveling

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Transferability of SWAT Models between SWAT2009 and SWAT2012

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JOURNAL OF ENVIRONMENTAL QUALITY 2014年第3期43卷 869-880页

作者： Seo, Mijin Yen, Haw Kim, Min-Kyeong Jeong, Jaehak Texas A&M Univ College Stn TX 77843 USA Texas A&M AgriLife Res Blackland Res Ctr Temple TX 76502 USA Rural Dev Adm Natl Acad Agr Sci Suwon 441707 Kyeonggi South Korea

In recent years, the Soil and Water Assessment Tool (SWAT) has experienced upgrades with enhanced functionalities and modeling capacities as it gets to the current version, SWAT2012. Changes in the SWAT code on a specific process may result in propagating influences in the output of other related processes. In this study, the characteristic significance of the enhancements in SWAT code was investigated using the two recent versions, SWAT2009 and SWAT2012. Using a global optimization technique, each model was calibrated for flow, sediment, and nutrient and then tested for transferability of parameters between the models. Results indicate that flow and water quality output were well calibrated with both models. However, the calibrated parameters determined by SWAT2009 and SWAT2012 were noticeably different, due mostly to the enhancements made in SWAT2012. Our results indicate that only the stream flow result was reliable when the models were upgraded or downgraded between the two versions after calibration. Sediment prediction was marginally reliable. SWAT parameters were nontransferrable if nutrient was the main output. The differences are due to various reasons, such as disparities in algorithms at the process level and propagation of the resulting uncertainty into higherorder processes.

关键词： Studies Watersheds Models Groundwater optimization algorithms Soil erosion Water quality

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A novel self-adaptive learning charged system search algorithm for unit commitment problem

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JOURNAL OF INTELLIGENT & FUZZY SYSTEMS 2014年第1期26卷 439-449页

作者： Niknam, Taher Bavafa, Farhad Jabbari, Masoud Shiraz Univ Technol SUTech Dept Elect & Elect Engn Shiraz Iran Islamic Azad Univ Marvdasht Branch Dept Elect Engn Marvdasht Iran

Charged System Search (CSS) is a new evolutionary algorithm inspired by the interaction between charged particles. This paper presents a modified CSS (SACSS) algorithm, which highly improves the performance of CSS and applies it to solve the unit commitment (UC) problem. In order to achieve better performance and higher speed in solving the UC problem, a self-adaptive reformation technique with tree updated schemes has been implemented. The proposed algorithm has been tested on 10, 20, 40 and 100 unit systems for one-day and scheduling horizon. The results are compared with the solutions obtained from other methods such as Lagrangian Relaxation (LR), Genetic Algorithm (GA), Particle Swarm optimization (PSO), Bacterial Foraging (BF) and Shuffled Frog Leaping Algorithm (SFLA). The results show the high performance and convergence speed of SACSS.

关键词： Charged system search economic dispatch generation scheduling optimization algorithms unit commitment

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Wideband digital integrators and differentiators designed using particle swarm optimisation

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IET SIGNAL PROCESSING 2014年第6期8卷 668-679页

作者： Gupta, Maneesha Relan, Bhavesh Yadav, Richa Aggarwal, Varun Netaji Subhas Inst Technol Dept Elect & Commun Engn Adv Elect Lab New Delhi 110075 India Netaji Subhas Inst Technol Dept Comp Engn New Delhi 110075 India AspringMinds Gurgaon Haryana India

Digital integrators (DIs) and digital differentiators (DDs) of second, third and fourth-order based on particle swarm optimisation (PSO) algorithm are presented. A modified particle swarm optimisation (MPSO) algorithm with reducing maximum velocity has been used to optimise the mean square error of the digital operators. Statistical and simulation results have been presented for comparing quality of optimal operators obtained by MPSO, genetic algorithm (GA), two variants of PSO and PSO-GA hybrid techniques. The results obtained for best solutions by the proposed algorithm are either superior or at par with the basic PSO variants and hybrid techniques. The proposed digital operators have also been simulated using MATLAB, and the results have been compared with that of existing DIs and DDs derived by different optimisation algorithms, to demonstrate the effectiveness of the use of proposed MPSO. The relative magnitude errors (dB) obtained for digital integrators and differentiators are as low as -40 and -35 dB, respectively, which are valid for almost the full band of normalised frequency.

关键词： MATLAB normalized frequency Particle swarm optimization maximum speed Methylprednisolone Suleptanate Mean square error optimization algorithms DIFFERENTIATORS parametric subharmonic oscillator

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Automated Design of Optimal Finite Thrust Orbit Insertion with Ballistic Flyby Constraints

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JOURNAL OF SPACECRAFT AND ROCKETS 2014年第6期51卷 1872-1884页

作者： Jesick, Mark Ocampo, Cesar Univ Texas Austin Dept Aerosp Engn & Engn Mech Austin TX 78712 USA Univ Texas Austin Dept Aerosp Engn & Engn Mech WR Woolrich Labs Austin TX 78712 USA

An automated method is developed to generate a minimum-fuel, finite thrust orbit insertion sequence while simultaneously generating a flyby trajectory of the same body that satisfies pre- and postflyby conditions in a general force field with ephemeris-level dynamics. The initial estimate requires no user input, and an impulsive solution is automatically converted to an optimal finite thrust transfer. As part of the initial estimate, a new method of generating ephemeris-level single flyby free returns is presented. A hybrid method is implemented for the optimal control solution whereby the costates are added to the vector of free parameters and the cost function is minimized directly. Analytic gradients are derived to decrease computation time and aid convergence of the optimization algorithm. The method is successfully applied in the Earth-moon system with application to human spaceflight and in the Saturn-Titan system with application to robotic spaceflight.

关键词： Optimal control Computer-Aided Design MANNED SPACE FLIGHT Cost functions computational time Earth-Moon couple optimization algorithms Optimal Automated methods

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Application of random search method for maximum power point tracking in partially shaded photovoltaic systems

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IET RENEWABLE POWER GENERATION 2014年第6期8卷 670-678页

作者： Sundareswaran, Kinattingal Peddapati, Sankar Palani, S. Natl Inst Technol EEE Dept Tiruchirappalli 620015 Tamil Nadu India Sudharsan Engn Coll Pudukkottai 620015 Tamil Nadu India

The power-voltage (P-V) curve of a photovoltaic (PV) power generation system under partially shaded conditions (PSCs) is largely non-linear and multimodal, and hence, global optimisation techniques are required for maximum power point tracking. A traditional optimisation algorithm is proposed here, namely random search method (RSM) for tracking the global maximum power point in a solar power system under PSC. The RSM is based on the use of random numbers in finding the global optima and is a gradient independent method. The major advantage of RSM is its very simple computational steps, which requires very less memory. The performance of RSM in tracking the peak power is studied for a variety of shading patterns and the tracking performance is compared with two-stage perturb and observe (P&O) and population-based particle swarm optimisation (PSO) methods. The simulation results strongly suggest that the RSM is far superior to two-stage P& O method and better than PSO method. Experimental results obtained from a 120-watt prototype PV system validate the effectiveness of the proposed scheme.

关键词： ELECTRIC POWER GENERATION SYSTEMS Thermoelectric system maximum loads random numbers visual tracking Solar collectors Search methods Photovoltaic systems maximum power point trackers Random search method Power Points optimization algorithms solar energy system PO

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Nonlinear system identification and control using state transition algorithm

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APPLIED MATHEMATICS AND COMPUTATION 2014年 226卷 169-179页

作者： Zhou, Xiaojun Yang, Chunhua Gui, Weihua Cent South Univ Sch Informat Sci & Engn Changsha 410083 Peoples R China Univ Ballarat Sch Sci Informat Technol & Engn Ballarat Vic 3353 Australia

By transforming identification and control for nonlinear system into optimization problems, a novel optimization method named state transition algorithm (STA) is introduced to solve the problems. In the proposed STA, a solution to a optimization problem is considered as a state, and the updating of a solution equates to a state transition, which makes it easy to understand and convenient to implement. First, the STA is applied to identify the optimal parameters of the estimated system with previously known structure. With the accurate estimated model, an off-line PID controller is then designed optimally by using the STA as well. Experimental results have demonstrated the validity of the methodology, and comparisons to STA with other optimization algorithms have testified that STA is a promising alternative method for system identification and control due to its stronger search ability, faster convergence rate and more stable performance. (C) 2013 Elsevier Inc. All rights reserved.

关键词： Nonlinear system identification PID controller State transition algorithm optimization algorithms

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Propeller sheet cavitation noise source modeling and inversion

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JOURNAL OF SOUND AND VIBRATION 2014年第5期333卷 1356-1368页

作者： Lee, Keunhwa Lee, Jaehyuk Kim, Dongho Kim, Kyungseop Seong, Woojae Seoul Natl Univ Res Inst Marine Syst Engn Seoul 151742 South Korea Seoul Natl Univ Dept Ocean Engn Seoul 151742 South Korea Agcy Def Dev Chang Won 645600 Gyeongnam South Korea

Propeller sheet cavitation is the main contributor to high level of noise and vibration in the after body of a ship. Full measurement of the cavitation-induced hull pressure over the entire surface of the affected area is desired but not practical. Therefore, using a few measurements on the outer hull above the propeller in a cavitation tunnel, empirical or semi-empirical techniques based on physical model have been used to predict the hullinduced pressure (or hull-induced force). In this paper, with the analytic source model for sheet cavitation, a multi-parameter inversion scheme to find the positions of noise sources and their strengths is suggested. The inversion is posed as a nonlinear optimization problem, which is solved by the optimization algorithm based on the adaptive simplex simulated annealing algorithm. Then, the resulting hull pressure can be modeled with boundary element method from the inverted cavitation noise sources. The suggested approach is applied to the hull pressure data measured in a cavitation tunnel of the Samsung Heavy Industry. Two monopole sources are adequate to model the propeller sheet cavitation noise. The inverted source information is reasonable with the cavitation dynamics of the propeller and the modeled hull pressure shows good agreement with cavitation tunnel experimental data. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Propeller sheet cavitation noise source modeling and inversion PROPELLER Inversion datum pressure sheet cavitation cavitation tunnel Affected Area Noise levels Noise sources optimization algorithms Hull

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Teaching and learning-based optimization algorithm for optimum design of steel buildings

Teaching and learning-based optimization algorithm for optim...

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2014 International Conference on Computing in Civil and Building Engineering

作者： Aydogdu, I. Akin, A. Department of Civil Engineering Akdeniz University P.O. Box 07058 Antalya Turkey Thomas and Betts Company MemphisTN United States

ISBN: (纸本)9780784413616

In this study, an algorithm is developed for the optimum design of the steel buildings. The optimum design problem is formulated according to LRFD-AISC. Design constraints include;(1) displacement limitations;(2) inter-story drift restrictions of multi-story frames;(3) strength requirements for beams and beam-columns;and (4) geometric constraints. The teaching and learning-based optimization (TLBO) technique, inspired by the interaction and outcome of teacher and learners, is employed to determine its optimum solution. The design algorithm developed selects optimum W sections for beams and columns of three-dimensional steel frames so that aforementioned constraints are satisfied and the frame has the minimum weight. A large-scale steel building has been designed by TLBO algorithm developed in order to test performance of the algorithm. © ASCE 2014.

关键词： Optimal design optimization algorithms Beams and girders Beam columns Design Algorithm algorithms Steels Minimum weight built structure Buildings Frame geometric constraint FRAMES Pedagogy Teaching

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