Modeling and control of discrete event systems using finite state machines with variables and their applications in power grids

Control theories for discrete event systems modeled as finite state machines have been well developed to address various fundamental control issues. However, finite state machine model has long suffered from the problem of state explosion that renders it unsuitable for some practical applications. In an attempt to mitigate the state explosion problem, we propose an efficient representation that appends finite sets of variables to finite state machines in modeling discrete event systems. We also present the control synthesis techniques for such finite state machines with variables (FSMwV). We first present our notion and means of control under this representation. We next present our algorithms for both offline and online synthesis of safety control policies. We then apply these results to the control of electric power grids.     

A hybrid local search algorithm for scheduling real-world job shops with batch-wise pending due dates

This paper aims at solving a real-world job shop scheduling problem with two characteristics, i.e., the existence of pending due dates and job batches. Due date quotation is an important decision process for contemporary companies that adopt the MTO (make to order) strategy. Although the assignment of due dates is usually performed separately with production scheduling, there exist strong interactions between the two tasks. Therefore, we integrate these two decisions into one optimization model. Meanwhile, each order placed by the customer defines a batch of jobs, for which the same due date should be set. Thus, the completion times of these jobs should be close to one another in order to reduce waiting time and cost. For this purpose, we propose a dispatching rule to synchronize their manufacturing progresses. A two-stage local search algorithm based on the PMBGA (probabilistic model-building genetic algorithm) and parameter perturbation is proposed to solve the integrated scheduling problem and its superiority is revealed by the applications to a real-world mechanical factory.     

Model experiment on anti-deformation performance of a self-supporting transmission tower in a subsidence area

A large number of high-voltage power transmission towers have recently been constructed in mining areas prone to subsidence.In order to ensure the safety of the transmission towers and the safe operati...     

基于消除地方高校成长上限基模的实证研究——以江西M学校为例

本文基于系统动力学反馈基模分析方法,在分析江西地方高校发展的成长上限基模和对策基模的基础上进行实证研究,引入相关数据,构建消除成长上限基模的顶点赋权模型,并提出综合对策思考。     

唐山市工业用水效率分析与控制

从万元工业取水量、用水重复利用率和万元工业取水量累积下降百分比3个方面,对唐山市近年来工业用水效率变化情况进行了分析计算,根据分析结果和唐山市工业用水存在问题,提出了坚持产业结构调整、提高用水技术、增加非常规水利用率等提高工业用水效率的控制方法及措施.     

对中央部门机关政府采购开展绩效评价的几点思考

中央部门机关政府采购绩效评价,应该以党和国家关于缋效管理和政府采购的一系列重要文件为指导,针对政府采购工作全过程,以绩效目标为牵引,以绩效指标和评价标准为重点,以完善的评价组织方法为推动力,贴近实际、注重实效,按照事前、事中、事后三个阶段,客观评定中央部门机关政府采购工作投入产出比,以及工作的效益和效率情况,为政府采购工作的开展提供借鉴.     

Design of a modified repetitive-control system based on a continuous–discrete 2D model

This paper concerns the problem of designing a modified repetitive-control system for a class of strictly proper plants. Repetitive control involves two types of actions: control and learning; but the insertion of a low-pass filter in a modified repetitive controller, which is employed to guarantee the stability of the system, mixes the two actions together. In this paper, a continuous–discrete two-dimensional model is first constructed. Next, the continuity of repetitive control and Lyapunov stability theory are applied to the model to establish two linear-matrix-inequality (LMI) based sufficient stability conditions, one for the design of the cutoff angular frequency and one for the design of the feedback gains. The features of these conditions are exploited to develop an iterative algorithm that searches for the best combination of the maximum cutoff angular frequency of the low-pass filter and the feedback gains. A numerical example illustrates the design procedure and demonstrates the validity of the method.     

Performance of Sewage Sludge Treatment and Electricity Generation by Different Configuration Microbial Fuel Cells

This paper compared the degradation efficiency of sludge organic matters and electric-production by two typical microbial fuel cells——dual-chamber microbial fuel cell(DMFC)and single chamber air cathode microbial fuel cell(SAMFC),and the variations of sludge protein,polysaccharide and ammonia nitrogen within the systems were also investigated.The results showed that the concentration of sludge soluble chemical oxygen demand,protein and carbohydrate of DMFC are higher than these of SAMFC during the systems operation,while DMFC can achieve a better ammonia nitrogen removal than SAMFC.Under the same operation condition,the stable voltage output of DMFC and SAMFC is 0.61 V and 0.37 V;the maximum power density of DMFC and SAMFC is 2.79 W/m3and 1.25 W/m3;TCOD removal efficiency of DMFC and SAMFC is 34.14%and 28.63%for 12 d,respectively.Meanwhile,DMFC has a higher coulomb efficiency than SAMFC,but both are less than5%.The results showed that DMFC present a better performance on sludge degradation and electric-production.