Generation of optimal schedules for metro lines using model predictive control

This paper presents a new methodology for computation of optimal train schedules in metro lines using a linear-programming-based model predictive control formulation. The train traffic model is comprised of dynamic equations describing the evolution of train headways and train passenger loads along the metro line, considering the time variation of the passenger demand and all relevant safety and operational constraints for practical use of the generated schedule. The performance index is a weighted sum of convex piecewise-linear functions for directly or indirectly modelling the waiting time of passengers at stations, onboard passenger comfort, train trip duration and number of trains in service. The proposed methodology is computationally very efficient and can generate optimal schedules for a whole day operation as well as schedules for transition between two separate time periods with known schedules. The use and performance of the proposed methodology is illustrated by an application to a metro line similar to the North-South line of São Paulo Underground.     

Compared Analysis of Metro Networks Supported by Graph Theory

This paper brings into focus the topological and geographical evaluation of metro networks through the definition of a methodological approach based on a set of indicators, a lot of which are defined in the sector literature. Once the methodology was stated, the results of an application on the metro networks of 13 big metropolitan areas were illustrated. Statistical comparative analyses are proposed to classify networks.     

基于MCGS组态软件的地铁列车事件记录仪软件开发

介绍了通过利用MCGS组态软件来实现对地铁列车事件记录仪的软件开发,其中对地铁列车事件记录仪及MCGS组态软件进行了简单的讲解,详细列出了事件记录仪需要记录的基本数据及实现的功能,并利用组态软件对事件记录仪进行软件开发,模拟运行。     

自纠正词对齐

词对齐是统计机器翻译系统的重要一环,但词对齐的获得往往基于序列模型的计算,而没有考虑语言的结构化信息及语言特征,从而造成词对齐中出现一些不符合语言特征的结果。文中提出一种词对齐的自纠正机制,以纠正词对齐中的错误部分。该机制使用一些语言学上的先验知识,对词对齐结果进行由粗颗粒度到细颗粒度的纠正。首先采用基于标点的方法对句对进行粗粒度化纠正,然后采用基于统计特征的方法对子句对进行细粒度化纠正。该自纠正过程不需要借助任何其他词对齐工具和新语料。实验结果显示,自纠正词对齐显著提高了词对齐的准确率,并提高了机器翻译的质量,其中粗粒度的纠正方法对翻译质量的提高最为显著,细粒度的纠正方法也提升了翻译质量,最终通过结合粗颗粒度和细颗粒度的纠正方法,使翻译结果相对基准系统取得了显著的提高。     

Review-driven configuration scheme evaluation methodology with configuration interaction effects

This study focuses on configuration scheme evaluation (CSE) based on customer perceptions deduced from online reviews. It is noteworthy that customers in different market segments often hold significant differences in their perceptions of the same configuration. Meanwhile, there may exist a potential dependency relationship between configurations referred to as configuration interaction increasing the complexity of CSE. This paper proposes a review-driven interacting CSE methodology fusing with review texts and configuration documents to address these challenges. First, three indexes, namely configuration differentiation, price consistency, and usage scenario similarity, are defined to identify targeted segments. Second, a differentiated calculation strategy is designed to measure configuration performances based on the configuration data and review data in the identified segments. Third, a configuration performance aggregation function that considers configuration interaction is developed based on the Choquet integral. Finally, two CSE problem about car and laptop products is analyzed using the proposed methodology to verify its applicability. Three comparative studies are also conducted to show the effectiveness and stability of the proposals.     

Bicriteria scheduling problem for unrelated parallel machines with release dates

This research proposes a heuristic and a tabu search algorithm (TSA) to find non-dominated solutions to bicriteria unrelated parallel machine scheduling problems with release dates. The two objective functions considered in this problem are to minimize both makespan and total weighted tardiness. The computational results show that the proposed heuristic is computationally efficient and provides solutions of reasonable quality. The proposed TSA outperforms other algorithms in terms of the number of non-dominated solutions and the quality of its solutions.     

基于SWRL规则的简单对等本体关联方法研究与实现

提出的"基于SWRL规则的简单对等本体关联方法"通过对SWRL规则的应用和扩充实现多个简单对等本体之间在类上的对应关联,从而可以达到构建简单的本体并通过本体之间的关联来获取更大的、更多的知识的目的.本法为本体的重用和映射提供了有效的方法.     

An evaluation methodology for reliable simulation based studies of routing protocols in VANETs

Vehicular Ad hoc NETworks (VANETs) have attracted much attention in the last decade. Many routing protocols have been proposed for VANETs and their performance is usually evaluated and compared using simulation-based studies. However, conducting reliable simulation studies is not a trivial task since many simulation parameters must be configured correctly. The selected parameters configuration can considerably affect the simulation results. This paper presents a methodology for conducting reliable simulations of routing protocols in VANETs urban scenarios. The proposed methodology includes relevant simulation aspects such as measurement period, selection of source–destination pairs for the communication traffic flows, number of simulations, mobility models based on road city maps, performance metrics and different analyses to evaluate routing protocols under different conditions. The proposed methodology is validated by comparing the simulation results obtained for Ad Hoc On-Demand Distance Vector (AODV) routing protocol with and without using the proposed methodology. The obtained results confirm that by using the proposed methodology, we can achieve more reliable simulations of VANETs routing protocols.     

软件重用控件技术在地铁仿真系统中的应用

对软件重用技术进行了研究,报告了控件技术的现状.为了能简单实现控件的跨平台,并且能简单得利用控件代码实现升级,需要开发可重用控件.提出了跨平台的软件重用控件技术,其中包括控件的移植、升级和组装技术.并以其在地铁信号仿真系统中的应用为例做了具体阐述和进一步分析,指出了以上方法的优点和存在的缺陷及处理方法.软件重用控件技术在一定程度上体现了组态化软件思想的优越性.     

Using a minimal fuzzy covering in decision-making problems

A new criterion is introduced for minimal fuzzy covering problems, which is a minimal value of the average misbelief contained in the possible alternatives. A bicriteria problem is obtained using this new criterion and the criterion of covering price minimization. The proposed approach is illustrated by an example.     

Bicriteria location of a semi-obnoxious facility

The problem of locating a new semi-obnoxious facility in an existing layout is considered. The facility interacts with the existing facilities, so that on one hand, it is desired to be placed close to them in order to minimize total transportation cost, but on the other hand it is not desired to be placed too close to them because it has certain undesirable effects. For this problem, a maximin–minisum bicriteria location model with rectilinear distances is developed. The resulting nonconvex bicriteria problem is decomposed into a series of linear bicriteria problems which are solved by an adaptation of the Fourier–Motzkin Elimination Method. An algorithm that constructs the entire nondominated and efficient sets is presented and it is illustrated in an example problem.     

基于MVB的地铁列车司机显示系统研究

以基于MVB总线的地铁列车为研究对象,介绍地铁列车网络控制的工作原理。通过对列车网络控制的各个子系统进行较为全面的分析,利用MCGS组态软件,开发了一套具备美观整齐性、安全可靠性并且易于二次开发等优点于一体的显示系统。     

A grasp algorithm for m-machine flowshop scheduling problem with bicriteria of makespan and maximum tardiness

In this paper we address the problem of minimizing the weighted sum of makespan and maximum tardiness in an m-machine flow shop environment. This is a NP-hard problem in the strong sense. An attempt has been made to solve this problem using a metaheuristic called Greedy Randomized Adaptive Search Procedure (GRASP). GRASP is a competitive algorithm and is a meta-heuristic for solving combinatorial optimization problems. We have customized the basic concepts of GRASP algorithm to solve a bicriteria flow shop problem and a new algorithm named B-GRASP (Bicriteria GRASP algorithm) is proposed. The new proposed algorithm is evaluated using benchmark problems taken from Taillard and compared with the existing simulated annealing based heuristic developed by Chakravarthy and Rajendran. Computational experiments indicate that the proposed algorithm is much better than the existing one in all cases.     

采用台达UPS的地铁弱电系统供电解决方案

地铁弱电系统通常主要由高可靠性UPS不间断供电,为一级用电负荷。该文介绍了该弱电系统各部分的供电需求,对UPS的容量确定、电池配置参数的计算、供电运行方式与切换逻辑进行了详细描述。     

Development of universal environment for constructing 5-axis virtual machine tool based on modified D–H notation and OpenGL

For construction of a universal 5-axis virtual machine simulation system, a new methodology is proposed in this paper. The OpenGL library is used to render the virtual environment and to display all motions of the virtual machine tool. In order to achieve the universal construction procedures, the D–H notation is adopted. The user interfaces are developed to help users to select the configuration of machine tool. Once the configuration is decided, the motion directions between adjacent links are known and the kinematic parameters are described by D–H notation. Then the post-processor is derived by D–H notation. Finally, the motion control simulation of the virtual machine tool is executed by D–H transformation matrix. This new methodology can assist developers in constructing the simulation system for the universal 5-axis virtual machine tool efficiently and effectively.     

Minimal spanning tree subject to a side constraint

This paper addresses the problem of finding a minimal spanning tree in a network subject to a knapsack-type constraint. The problem is shown to belong to the class of NP -complete problems. Certain properties of an optimal solution to this problem are established considering a bicriteria spanning tree problem. Based on these, an algorithm is proposed which is mainly a branch and bound scheme branching from the test upper bound and generating efficient frontiers successively. It also uses certain effective heuristics and bounds that are obtained in polynomially bounded operations. The algorithm is validated and a numerical example is included.     

Technical Efficiency of European Metro Systems: The Effects of Operational Management and Socioeconomic Environment

This study focuses on the relationship between the operational performance of metro systems and their socioeconomic contexts. We use a two-stage methodology applied to a sample of 17 European metro systems. First, we apply a stochastic frontier approach to establish the optimal production function and to evaluate the efficiency and effectiveness levels of each firm through offer and demand-characterizing indicators, respectively. Only internal production factors are included in the first stage of this analysis. In a second stage, we use a similar modeling approach, but considering an additional set of variables characterizing the socioeconomic environment of the urban areas in which metro systems operate. This method allows observing the effects on operational performance measurements due to the inclusion of external factors, and consequently, drawing some conclusions on the technical efficiency of metro systems and their operations in beneficial or adverse surrounding environments. Different scores resulting from both perspectives evidence the contributions of the socioeconomic factors to improve the reliability of performance measurements and to reduce false inefficiencies. The results show that 12 of the analyzed systems are being affected by an unfavourable socioeconomic environment and/or their network suffers from some adequacy problems with regard to demand. The remaining five systems should improve their management strategies, since their results are being supported by a favourable surrounding environment.     

Selection of control structure for distributed model predictive control in the presence of model errors

This paper presents a new methodology for selecting control structure in the context of distributed model predictive control. An index was developed to quantify the performance of distributed MPC strategies in the presence of model errors. This index was used for two purposes: to solve the decomposition problem whereby the process is decomposed into parts and to compare distributed MPC strategies with different degrees of coordination. Then, a multi-objective Mixed Integer Nonlinear Programming MINLP formulation is proposed to achieve an optimal trade-off between performance and structure simplicity.Four examples are considered to illustrate the methodology. The simulation results are consistent with the conclusions obtained from the analysis. The proposed methodology can be applied at the design stage to select the best control configuration in the presence of model errors.     

A novel real-time fuzzy adaptive auto-tuning scheme for cascade PID controllers

This paper presents a novel fuzzy auto-tuning methodology to continuously adapt PID control actions without interrupting the normal process operation. New auto-tuning rules are introduced to schedule a gradual and guided activation of each individual P, I and D control mode in three adjustable functional control zones. An auto-scaling procedure has been incorporated to generalize the autotuning scheme to efficiently respond to any set-point change outside a pre-defined operating span. In contrast to existing auto-tuning algorithms, the proposed scheme is not an on-demand auto-tuning methodology and hence does not require alertness of an experienced engineer to initiate and supervise its initial operation in a separate commissioning identification pre-test. This interesting feature provides a new perspective on PID auto-tuning approaches. Performance of the proposed auto-tuning scheme is practically evaluated in a real pilot plant within a networked control system (NCS) configuration, realized by industrial Ethernet and Foundation Fieldbus technologies. An extensive series of test scenarios has been conducted to explore efficiency of the proposed auto-tuning methodology to cope with fixed and varying operating set-points under uncertain and variable network transmission time delays and external disturbance.