A Technique of Automatically Tuning Decision Parameters for Rule‐Based Defect Classifier

In automatic defect classification of semiconductor wafers using scanning electron microscope images, we propose a technique of tuning decision parameters for rule‐based defect classifiers. The proposed method adopts a coarse‐to‐fine search for reduction in processing time. However, due to search leakage, there is no guarantee that the same solutions as in a full parameter search can be obtained. In order to prevent leakage in the coarse search theoretically, the proposed method evaluates a candidate parameter set based on the estimated range of classification accuracy attained by not only the candidate but the surrounding solutions eliminated by the coarse search. Experiments on real image data demonstrate the effectiveness of the proposed method. The proposed method can extract the same solutions as the full parameter search within almost the same processing time as the conventional coarse‐to‐fine search. When the sampling step of the coarse search is three to six, while the tuning time of the conventional coarse‐to‐fine search is 1 to 21 s, that of the proposed method is 5 to 35 s.     

Generation of signals with specified second‐order properties for constrained systems

This contribution considers the problem of realizing an input signal with a desired autocorrelation sequence satisfying both input and output constraints for the system it is to be applied to. This is an important problem in system identification, firstly, because the quality and accuracy of the identified model are highly dependent on the excitation signal used during the experiment and secondly, because on real processes, it is often important to constrain the input and output of the process because of actuator saturation and safety considerations. The signal generation is formulated as a model predictive controller with probabilistic constraints to make the algorithm robust to model uncertainties and process noise. The corresponding optimization problem is then solved with tools from scenario‐based stochastic optimization. To reduce the model uncertainties, the method is made adaptive where a new model of the system and its uncertainties are reidentified. The algorithm is successfully applied to a simulation example and in a practical experiment for the identification of a quadruple tank lab process. Copyright © 2015 John Wiley & Sons, Ltd.     

Design of PSO‐based fuzzy logic controller for single axis magnetic levitation system

In this paper, a particle swarm optimization (PSO) method is proposed to design an optimal robust fuzzy logic controller (FLC). The objective of this paper is to design a nonlinear optimal robust controller for the single axis magnetic levitation system with high accuracy. PSO algorithm is applied to search globally optimal parameters of FLCs. Three different FLCs are designed. First, proportional derivative (PD)‐like FLC. Second, the FLC is based on the PSO algorithm to find the optimal range of the eight linguistic membership functions (FLC1 with PSO algorithm). Finally, the FLC is based on the PSO algorithm to find the optimal range and shape of the four linguistic membership functions (FLC2 with PSO algorithm). The performances of three different FLCs are compared. Simulation results show that PSO‐based optimal FLCs find the optimal range and shape of the four linguistic membership functions and achieved better performance than the other proposed controllers, minimizing 48 fuzzy rules. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

智能配电网不确定性建模与供电特征优化技术综述

随着配电网智能化建设水平的提高,智能配电系统的运行与控制将受到大量不确定因素的影响。如何应对与控制不确定因素对供电特征所带来的不确定影响是智能配电网建设与运行面临的本质问题之一。首先,分析智能配电网所包含的源、网、荷、信息系统与外部异质能源系统等五类不确定因素及其对电压稳定性、电能质量等供电特征的不确定影响,概括了智能配电网不确定性分析与优化控制的研究框架。然后,分别从不确定因素特性及建模、因果式与关联式不确定性分析、供电特征不确定运行优化及其支撑技术三个方面进行了梳理和总结,并展望了各自的发展方向及其面临的挑战,以期为后续研究提供借鉴。     

Determination of loss‐minimum configuration with mathematical optimality in a three‐sectionalized three connected distribution feeder network

In a distribution system, in order to enhance the reliability of power supply, the distribution feeder is divided into several sections by installing sectionalizing switches, and then each of the sectionalized sections is connected to a different feeder. For example, one feeder is divided into three sections by two sectionalizing switches, and then each of the divided sections is connected to the other feeder through sectionalizing switch. Since a distribution system with many feeders has many sectionalizing switches, the system configuration is determined by states (opened or closed) of sectionalizing switches. Usually, a power utility tries to obtain distribution loss‐minimum configuration among large numbers of configuration candidates. However, it is very difficult to determine the loss‐minimum configuration such that the mathematical optimality is guaranteed, because it is well known that determination of a distribution system's configuration is to decide whether each sectionalizing switch is opened or closed by solving a combinatorial optimization problem. In this paper, the authors propose a determination method of loss‐minimum configuration by which the mathematical optimality is guaranteed for a three‐sectionalized three‐connected distribution feeder network. A problem to determine the loss‐minimum configuration is formulated as a combinatorial optimization problems with four operational constraints ( feeder capacity, voltage limit, radial structure, and three‐sectionalization). In the proposed method, after picking up all partial configurations satisfied with radial structure constraint by using enumeration method, optimal combination of partial configurations is determined under the other operational constraints by using conventional optimization method. Numerical simulations are carried out for a distribution network model with 140 sectionalizing switches in order to examine the validity of the proposed algorithm in comparison with one of conventional meta‐heuristics (tabu search). © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 56– 65, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20530     

Multi‐model unfalsified adaptive switching control: Test functionals for stability and performance

The paper studies how to infer behavioral features of a potential loop, consisting of an uncertain plant interconnected in feedback with a candidate controller, on the grounds of experimental data taken from the same plant possibly driven by a different controller. In such a context, convenient tools to work with are test functionals, computed via a virtual experiment, which quantify the discrepancy between the potential loop and the so‐called ‘tuned‐loop’ or ‘reference‐loop’ related to the same candidate controller. Several test functionals are considered and analyzed so as to unveil conditions under which their adoption can accomplish the desired goals. These results are shown to be of practical relevance for on‐line performance inference of feedback control systems and implementation of highly performing adaptive switching control systems. Copyright © 2011 John Wiley & Sons, Ltd.     

A parametric assessment approach to solving facility‐location problems with fuzzy demands

In real‐world applications, sometimes randomness and fuzziness may coexist. In facility‐location problems, the data expressed in natural language may contain vague information. We discuss the uncertainty included in demands in facility‐location problems. The uncertain demand is called fuzzy demand in this paper. In the facility‐location model, the parameters of fuzzy demand are determined by calculating the estimated expected value of the fuzzy demand, which is obtained by using the estimated parameters of the underlying probability distribution function of the fuzzy data. Moreover, we propose a defuzzification formula of the fuzzy demand called the realization of fuzzy demand. The defuzzification formula of fuzzy demand comprises the upper bound and the lower bound of the fuzzy demand. Moreover, the error of the fuzzy demand is assessed as the mean absolute percentage error of the fuzzy demand. Empirical studies show that we can solve real‐life location problems by using the defuzzification formula of fuzzy demand and get higher profit in our facility‐location model than by using conventional methods. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Optimized Energy‐Saving Speed Profile in Linear‐Motor Railway System

The most striking characteristic of linear‐motor railway system is that the structure consists of a primary and secondary linear induction motor (LIM). The primary side of the LIM is installed in a rolling stock, and the secondary side of LIM is installed on the track. The magnetic attractive vertical force produced by the LIM increases the running resistance since this force is in the same direction as the gravitational force due to which rolling stocks gain weight virtually from the track side of view. In addition, the efficiency of the LIM has different characteristics of efficiency compared with the rotary motor. Previous studies have focused on the design method of LIM to improve motor efficiency and decrease energy consumption. However, it is a well‐known fact that this kind of approach requires hardware renewal which requests large amount of investments. The purpose of this study is to analyze these characteristics of LIM effects and design the optimal speed profile to minimize the energy consumption as a linear‐motor railway system. This smart and economic energy‐saving approach is based on the optimization of speed profiles of the linear‐motor railway system using dynamic programming.     

A two‐layered neighborhood tabu search‐based approach to optimal allocation of D‐FACTS in distribution systems

This paper proposes two‐layered neighborhood tabu search for determining the optimal allocation and output of D‐FACTS device in a distribution system with uncertain wind power generation. In recent years, wind power generation has been introduced into distribution systems for clean and inexhaustible distributed generation. However, a distribution system with wind power generation often encounters the reverse flow due to the uncertain output performance of wind power generation. As a result, the voltage variation may become much larger. In this paper, two‐layered neighborhood tabu search is proposed to determine the optimal allocation and output of D‐FACTS devices. To consider the uncertainty of wind power generation, this paper carries out Monte Carlo simulation to evaluate the probabilistic voltage assessment in the distribution system with uncertain wind power generation. The proposed method is successfully applied to a sample system. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(3): 29–37, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20103     

Solving the m‐way graph partitioning problem using a genetic algorithm

The m‐way graph partitioning problem is of central importance in combinatorial optimization. It has many important applications in fields such as VLSI circuit design, task allocation in distributed computing systems, and network partitioning. In this paper, we propose an efficient genetic algorithm to solve this problem. The proposed method searches a large solution space and finds the best possible solution by adjusting the intensification and diversification automatically during the optimization process. The proposed method is tested on a large number of instances and compared with some existing algorithms. The experimental results show that the proposed algorithm is superior to its competitors in terms of computation time and solution quality. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Integrated method of determining transmission and distribution loss‐minimum network configurations

In Japan, the secondary transmission system (66 kV, 77 kV) and distribution system (6.6 kV) with loop structures are operated using the radial configuration. The transmission and distribution network configurations must be determined so as to keep the radial configuration and satisfy the operational constraints such as line capacity, voltage drop, and so on. However, the configuration candidates are too many, and it is not easy to determine transmission and distribution loss‐minimum network configurations comprehensively. In this paper, the authors propose an integrated method of determining the transmission and distribution loss‐minimum network configurations under the operational constraints within practical computation time. In order to check the validity of the proposed method of determination, numerical simulations using the proposed method are carried out for a real‐scale Japanese transmission and distribution network model with 2²⁰⁹⁸ configuration candidates. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Adaptive control for high‐order time‐delay uncertain nonlinear system and application to chemical reactor system

This paper focuses on global adaptive state‐feedback stabilization for a class of high‐order uncertain nonlinear systems with multiple delays. Restriction on system growth is relaxed. Two dynamic gains are introduced to deal with uncertainty and nonlinear growth rate of the system. Without precise information about time‐delay being needed and only by like Lyapunov function, a new control strategy is presented based on homogeneous domination idea and two necessary transformations. As an application, the developed scheme is utilized to control design of a two‐stage chemical reactor with delayed recycle streams. Copyright © 2014 John Wiley & Sons, Ltd.     

Predictor‐based adaptive dynamic surface control for consensus of uncertain nonlinear systems in strict‐feedback form

This paper investigates the leader–follower consensus problem of uncertain nonlinear systems in strict‐feedback form. By parameterizations of unknown nonlinear dynamics of the agents, an adaptive dynamic surface control with the aid of predictors, tracking differentiators is proposed to realize output consensus of the multi‐agent systems. Unlike the existing adaptive consensus methods, the predictor errors are used to learn the unknown parameters, which can achieve fast learning without high‐frequency signals in control inputs. As a fast precise signal filter, the tracking differentiator is used in the control design instead of first‐order filters, which can further improve the control performance. Based on graph theory and Lyapunov stability theory, it is shown that the outputs of all followers ultimately synchronize to that of the leader with bounded tracking errors. Simulation results are provided to validate the effectiveness and advantage of the proposed consensus algorithm. Copyright © 2016 John Wiley & Sons, Ltd.     

Deliverable‐power dependence on distribution‐line resistance and number of loads in low‐voltage DC distribution system

In this paper, we show that in a low‐voltage DC distribution system the deliverable power to a load has an upper limit P_lim due to the voltage instability at the receiving ends. On the basis of the previously derived concept of P_lim, we obtain the dependence of P_lim on the distribution line resistance R. In addition, we investigate the influence of the number of loads on P_lim. The result shows that a distribution line of lower R causes P_lim to be lower. This reduction in P_lim becomes more distinct for a larger number of loads. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

中压目标网架规划中供电分区优化模型和方法

文中首先明确了供电分区划分的目的是实现配电网规划的由大到小和由繁到简,原则是各分区独自规划优化方案能够自动实现全局范围的“技术可行、经济最优”或“次优”。然后,基于候选主干通道布局,提出了用于中压目标网架规划的供电分区全局优化模型和相应的启发式方法,使得不同水平规划人员可以得到基本一致的分区优化划分方案。最后,通过算例表明,所提方法在明显节约线路投资的同时,还能够有效改善线损、电压合格率和可靠性指标。     

Determination method for loss‐minimum configuration considering reconnection of distributed generators

In the field of electrical power system, various approaches, such as utilization of renewable energy, loss reduction, and so on, have been taken to reduce CO₂ emission. So as to work toward this goal, the total number of distributed generators (DGs) using renewable energy connected into 6.6‐kV distribution systems has been increasing rapidly. The DGs can reduce distribution loss by appropriate allocation. However, when a fault occurs such as distribution line fault and bank fault, DGs connecting outage sections are disconnected simultaneously. Since the simultaneous disconnection of DGs influences restoration configuration and normal configuration after the restoration, it is necessary to determine the system configuration in the normal state considering simultaneous disconnection of DGs. In this paper, the authors propose a computation method to determine the loss minimum configuration in the normal state considering reconnection of DGs after simultaneous disconnection by fault occurrence. The feature of determined loss minimum configuration is satisfying with operational constraints even if all DGs are disconnected from the system. Numerical simulations are carried out for a real‐scale distribution system model with 252 sectionalizing switches (configuration candidates are 2²⁵²) and 120 DGs (total output is 38.46 MW which is 23% of total load) in order to examine the validity of the proposed algorithm. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(4): 7–14, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21142     

基于鲁棒优化的网架重构机组恢复顺序优化

在当前以火电为主的系统中,大停电后机组恢复时间的长短对重构效果影响显著。针对机组启动准备时段和启动时段可能出现的时间延迟,以最小化重构期间的电量不足为优化目标,构建了计及火电机组启动时间不确定性的机组恢复顺序鲁棒优化模型。通过交叉粒子群算法与CPLEX优化求解相结合,可获得量化表征恢复效果和运行可靠性的机组恢复顺序,为调度人员应对可能出现的最严重机组恢复迟滞场景提供了更加全面的决策参考。对于调度人员自行拟定的机组恢复顺序,还可根据运行经验预估其成功实施的概率,通过CPLEX求解并筛选关键时步,为调度人员有的放矢地保证恢复效果提供量化指导。针对新英格兰10机39节点系统和某区域电网的仿真结果验证了该方法的有效性。     

An extension of the FFT‐based algorithm for the match‐count problem to weighted scores

The match‐count problem on strings is the basic problem of counting the matches of characters between two strings for every possible alignment. The problem is classically computed in O (σ n log m ) time using a fast Fourier transform (FFT) for two strings of lengths m and n (m ≤ n ) over an alphabet of size σ . This paper extends the target of this FFT‐based algorithm to a weighted version of the problem, which computes the sum of similarities between characters instead of the number of matches. The algorithm extended in this paper can solve the weighted match‐count problem in O (dn log m ) time by mapping characters to numerical vectors of dimensionality d . This paper also evaluates the usefulness of the extended algorithm by applying it to plagiarism detection in documents. The experimental results show that the proposed algorithm is applicable to general vector representation of words and that the obtained plagiarism detection method can extremely reduce the processing time with a slight decrease of accuracy from the method based on the normal match‐count problem.     

Observer‐based nonlinear feedback decentralized neural adaptive dynamic surface control for large‐scale nonlinear systems

This paper presents a nonlinear gain feedback technique for observer‐based decentralized neural adaptive dynamic surface control of a class of large‐scale nonlinear systems with immeasurable states and uncertain interconnections among subsystems. Neural networks are used in the observer design to estimate the immeasurable states and thus facilitate the control design. Besides avoiding the complexity problem in traditional backstepping, the new nonlinear feedback gain method endows an automatic regulation ability into the pioneering dynamic surface control design and improvement in dynamic performance. Novel Lyapunov function is designed and rigorous stability analysis is given to show that all the closed‐loop signals are kept semiglobally uniformly ultimately bounded, and the output tracking errors can be guaranteed to converge to sufficient area around zero, with the bound values characterized by design parameters in an explicit manner. Simulation and comparative results are shown to verify effectiveness.     

连续加热炉的优化设定值控制

本文从加热过程分析,导出连续加热炉动态数学模型,用加热炉中的可测变量来估计炉内钢坯的温度分布,把铜坯出炉温度与设定值优化控制联系起来,并给出最佳炉温设定值的计算.