An integrated DEMATEL and Fuzzy ANP techniques for evaluation and selection of outsourcing provider for a telecommunication company

In recent years, strategy aspects related to core competency, risk analysis and organizational flexibility especially have been growing. This trend has led researchers and industries to become more interested in the multi-criteria decision making (MCDM) models for selecting outsourcing providers. The efficiency of decision-making mostly depends on the ability of decision-makers analyzing the complex cause and effect relationship between criteria and taking effective actions based on the analysis. Using an analytical method to select the most eligible outsourcing provider is significant for a company which desires to improve its competitiveness. In this study, a fuzzy integrated multi-criteria decision making method for evaluation and determination of an outsourcing provider for a telecommunication company is analyzed by using DEMATEL and Fuzzy ANP multi-criteria decision making techniques. First, DEMATEL method is used in order to put forward the interrelationship among the main criteria which are determined in the study for outsourcing selection process. Then, local weights of the sub-criteria and sub-subcriteria are calculated by Fuzzy ANP approach on the basis of cause-effect relationships that are exposed through DEMATEL method. The local weights are put into ANP supermatrix, and calculations are implemented to select out the most eligible outsourcing provider.     

Intelligent solution and analysis of goal programmes: the GPSYS system

An overview of GPSYS, an intelligent linear and integer goal programming system is presented in this paper. The intelligent goal programming system is one which is designed to allow a non-specialist access to, and clear understanding of, goal programming solution and analysis techniques. GPSYS is equipped with GP speed up techniques and analysis tools such as Pareto detection and restoration, normalisation, automated lexicographic redundancy checking and an interactive facility.     

GAHPSort: A new group multi-criteria decision method for sorting a large number of the cloud-based ERP solutions

Companies are increasingly introducing cloud-based ERP systems as a solution for integrating all-in-one business functions into the Internet. To support this decision, this paper proposes the Group Analytic Hierarchy Process Sorting (GAHPSort) method, which extends the classical AHP for sorting problems with a large number of alternatives. Our study is specifically based on two steps: Firstly, the cloud-based ERP vendors are sorted with GAHPSort into two classes: accepted or rejected. Secondly, a single solution is selected with Analytic Network Process (ANP) among accepted vendors. To validate our model, we present the results obtained from a real case study.     

转子系统振动的灰色关联控制方法研究

将灰色关联控制理论应用于转子系统的振动主动控制,设计了转子系统振动的灰色关联控制方案．该方案依据转子工作曲线和实测曲线的关联度实现对转子振动的控制,因此不需要转子系统的精确的数学模型,具有建模迅速,控制及时、准确,便于工程实现等优点．将该方案应用于一带电磁阻尼器的单盘转子系统的振动主动控制中,仿真结果验证了该控制方法的有效性．     

Fault tolerant control of a simulated hydroelectric system

This paper analyses the application of two fault tolerant control schemes to a hydroelectric model developed in the Matlab and Simulink environments. The proposed fault tolerant controllers are exploited for regulating the speed of the Francis turbine included in the hydraulic system. The nonlinear behaviour of the hydraulic turbine and the inelastic water hammer effects are taken into account in order to develop a high-fidelity simulator of this dynamic plant. The first fault tolerant control solution relies on an adaptive control design, which exploits the recursive identification of a linear parametric time-varying model of the monitored system. The second scheme proposed uses the identification of a fuzzy model that is exploited for the reconstruction of the fault affecting the system under diagnosis. In this way, the fault estimation and its accommodation is possible. Note that these strategies, which are both based on identification approaches, are suggested for enhancing the application of the suggested fault tolerant control methodologies. These characteristics of the study represent key issues when on-line implementations are considered for a viable application of the proposed fault tolerant control schemes. The faults considered in this paper affect the electric servomotor used as a governor, the hydraulic turbine speed sensor, and the hydraulic turbine system, and are imposed both separately and simultaneously. Moreover, the complete drop of the rotational speed sensor is also analysed. Monte-Carlo simulations are also used for analysing the most important issues of the proposed schemes in the presence of parameter variations. Moreover, the performances achieved by means of the proposed solutions are compared to those of a standard PID controller already developed for the considered model. Finally, these strategies serve to highlight the potential application of the proposed control strategies to real hydraulic systems.     

Turbine-generator system control for a HTGR power plant

Dual turbine-generator systems offer several operating advantages for large electric power generating plants. In order that these benefits be fully realized, it is necessary that the twin turbine-generator system, including its associated control systems, perform satisfactorily in a variety of normal and energy operating modes. This paper combines nonlinear simulation and linear multivariable systems analysis techniques to investigate system dynamic behavior and governor design. Specific results are reported for load following operation in which one turbine-generator is shut down.     

基于灰色预测理论的转子系统振动主动控制

以灰色预测控制理论为基础,采用现代控制理论中的二次型优化原理,以控制力和响应加权最小为目标函数,设计了两种基于灰色预测理论的转子系统振动主动控制方案——灰色 GM(1,1)预测优化控制方案和灰色 Verhuslt 预测优化控制方案.并将该两种方案分别应用于带电磁阻尼器转子轴承系统的转子振动主动控制中,通过数值仿真验证了两种控制方法的有效性,并对两种方法的控振效果进行了比较.     

感应电动机效率优化的自抗扰控制研究

针对现有电动机效率优化控制方法存在控制算法复杂的问题,提出了一种基于改进自抗扰控制器的动态解耦控制策略。自抗扰控制器省去了微分跟踪器,采用线性的扩张状态观测器和线性状态误差反馈控制律,使控制算法得以简化。仿真和实验结果表明,该控制策略在保证电动机轻载运行时效率优化的同时,具有较强的抗干扰能力和鲁棒性,提高了效率优化过程中电动机转速的动态响应速度。     

Robust impedance control of a hydraulic suspension system

A novel robust impedance control approach is developed to control dynamic behavior of a vehicle subject to road disturbances. This behavior is predetermined as an impedance rule to achieve passenger comfort and vehicle handling by the use of a hydraulically actuated suspension system. Impedance control law is simple, free of model and efficient to apply for a broad range of road conditions. Moreover, it relates comfort to handling. This control approach can provide a desired comfort when passing a bump, and both desired comfort and handling after passing a bump. Robust position and force controls are used to implement the robust impedance control with the presence of uncertainties. A transformed proportional–integral–derivative control is proposed to perform the robust control. The system stability is analyzed and analytical results are confirmed by simulations. A quarter‐car model of suspension system and a nonlinear model of hydraulic actuator are used to simulate the control system. Copyright © 2009 John Wiley & Sons, Ltd.     

桥式起重机定位防摆改进型自抗扰控制

为解决严重外界干扰下桥式起重机长距离运输过程中定位困难、消摆时间长的问题,根据起重机先加速、再匀速、后减速的远程运输特点,利用两段Sigmoid函数,设计了可按需调整各阶段速度且高阶连续的新型跟踪微分器;采用Sigmoid函数构造了增益时变且连续可微的扩张状态观测器,使其具有“大误差小增益,小误差大增益”特性,克服了经典ESO增益在切换点处的突变问题,抑制了观测信号的微分峰值现象,实现了位移和摆角控制回路间的解耦;利用tanh函数改进了误差反馈控制律,避免了大扰动下的控制量饱和问题;综合形成了适用于起重机长距离运输、且能最大程度抑制振动和冲击的改进型自抗扰控制器,并对闭环系统的稳定性进行了严格的理论证明.仿真及实验结果表明,改进型自抗扰控制器在大干扰影响下可全过程平稳且基本无摆地将负载搬运到目标位置.     

Development of a fuzzy ANP based SWOT analysis for the airline industry in Turkey

Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis has been widely used to evaluate alternative strategies in order to determine the best one for given business setting. This study aims at providing a quantitative basis to analytically determine the ranking of the factors in SWOT analysis via a conventional multi-criteria decision making method, Analytic Network Process (ANP). The ANP method is preferred in this study because of its capability to model potential dependencies among the SWOT factors. The study presents uniqueness in the way it incorporates inherent vagueness and uncertainty of the human decision making process by means of the fuzzy logic. The proposed SWOT fuzzy ANP methodology was implemented and tested for the Turkish airline industry. The results showed that the SWOT fuzzy ANP is a viable and highly capable methodology that provides invaluable insights for strategic management decisions in the Turkish airline industry, and can also be used as an effective tool for other complex decision making processes.     

Mathematical model for predictive control of the bell-less top charging system of a blast furnace

Modern blast furnaces use bell-less top systems for the charging of the solid feed into the furnace. The complete potential of the charging system for distributing the material in the furnace cross-section in any desired profile can be achieved only by using a suitable charge distribution model. By considering the flow of different types of solid particles like iron ore, sinter and coke through the bin and rotating chute, equations have been developed for the particle trajectories. The formation of the ring shaped hill of material by the accumulation of the falling material has been modeled considering the angle of repose, rolling and layer penetration. These relationships have been combined with appropriate corrections for the burden descent and the mixed layer formation to develop the overall geometry of the stock line. The burden charge model has been used in an optimization routine to determine the best charging pattern to transit from an existing stock line geometry to a new geometry. The models have been tested in an operating furnace and incorporated in a supervisory control system.     

Reinforcement learning for combined production-maintenance and quality control of a manufacturing system with deterioration failures

This paper describes and examines thoroughly a stochastic production/inventory system that produces a single type of products. During the production process, the system is affected by several deterioration failures. It is restored to its initial and previous deterioration state by repair and maintenance activities. Both maintenance and repair duration are assumed as exponential random variables. Moreover, the quality of the manufactured products is assumed to be affected by the current deterioration level of the system. The aim of this paper is to find the optimal trade-off between conflicting performance metrics for the optimization of the total expected profit of the system. To tackle such optimization problems, researchers frequently employ Dynamic Programming. This method, though, is not appropriate for the addressed problem due to complexity reasons. To this end, a Reinforcement Learning-based approach is proposed in order to obtain the optimal joint production, maintenance and product quality control policies. To the authors’ knowledge, the proposed approach is novel and there are few examples of such implementation in the academic literature.     

无人炮塔炮控系统自抗扰控制

本文运用机器人分析技术来建立无人炮塔的数学模型,这种方法考虑了炮塔方位向和高低向之间的耦合关系.同时,由于陀螺机构测得的是惯性空间中的角位移,结合三轴稳定原理,对无人炮塔的方位向和高低向射角进行修正,实现火炮轴线在惯性空间中的稳定.针对炮控系统这一包含非线性和不确定性的复杂系统,能在参数摄动和不确定的外部扰动的情况下获得高跟踪精度和稳定性,提出了一种基于自抗扰控制的解耦方法.系统的内部参数摄动、外部扰动和耦合项作为总扰动被扩张状态观测器估计出来,然后在采样间隔被补偿掉.将仿真结果与PID控制作比较,结果表明该控制算法能够有效抵抗系统的不确定非线性因素,并验证了其强鲁棒性和有效性     

前后端分离Web系统下一种访问控制方法的设计与实现

为了在不降低系统性能的前提下,提升前后端分离Web系统内访问控制模块的开发效率,介绍了一种以基于角色的访问控制为核心思想,通过解析特定格式的API访问地址来调用不同的Spring MVC拦截器以决定控制策略的访问控制模块开发方法。该方法实现了在前后端分离Web系统开发过程中,业务逻辑与访问控制分离,使开发者在扩展与维护系统访问控制模块时能够通过修改所涉及到功能的API访问地址使其变得更加轻松与便捷。     

非线性系统主动容错控制综述

以故障发生部位为分类视角,分别从传感器故障、执行器故障及其他部件故障3个方面,较为详细地对近5年非线性系统主动容错控制的研究进展情况进行了归纳和总结,重点讨论了执行器故障的容错控制问题,并对所存在的问题与未来的发展趋势进行了探讨。     

Nonlinear control of a 3-pole active magnetic bearing system

Cost-down is one of the major challenges for active magnetic bearing (AMB) systems in industry today. An AMB system with three magnetic poles is proposed and studied in this work. Compared to the popular 8-pole AMB, the 3-pole system requires fewer power amplifiers, which can reduce the overall cost. The primary problem in the 3-pole AMB is the strong coupling in the magnetic flux between magnetic poles. Consequently, the system is strongly nonlinear not only in states but also in control inputs. In particular, the input currents enter the system model in a quadratic form. The feedback linearization problem for this non-affine nonlinear system is solved. Then, the integral sliding mode control method is incorporated to yield a robust nonlinear controller for the 3-pole AMB system. It is found through simulations and experiments that the proposed controller can achieve stability and high steady-state accuracy even under the influence of large uncertainties.     

高温力学试样机监控系统的设计

设计了高温力学试样机的计算机监控系统，介绍了其组成、结构、功能与特点，并详细介绍了其软件设计，实现了对高温力学试样机的实时监控和数据管理。     

风能转换系统执行器故障主动容错控制

提出了一种新颖的风能转换系统滑模主动容错控制策略.针对风能转换系统执行器故障,运用预测控制思想和迭代算法,设计了一种故障观测器.在设定的优化时域长度内,利用实际系统与故障观测器的输出差值,通过反复迭代运算,不断地对虚拟故障信号进行调整,使其能有效地拟合实际系统执行器故障,并根据故障观测值实时调整滑模容错控制器结构.未发生故障时,故障观测值为零,系统在滑模控制器控制下稳定运行;执行器发生故障时,运用故障观测值实时调整滑模容错控制项,并用双曲正切函数代替符号函数,消除抖动.仿真实验结果表明,滑模容错控制器下的系统具有良好的容错能力,提高了风能转换系统最大风能捕获效率.