变频调速技术在煤矿井下瓦斯排放中的应用

瓦斯排放是高瓦斯矿井瓦斯超限后所必须采取的有效措施。文章在分析传统排放方法所存在的缺陷的基础上,设计了一种基于变频调速技术的闭环型瓦斯排放系统,并介绍了其基本构成和工作原理。该系统以排放出的瓦斯浓度为参量,通过PID算法调节局部通风机转速,实现了掘进工作面瓦斯的安全排放,保证了煤矿井下的生产安全。     

The Pareto-optimal Solution Set of the Equilibrium Network Design Problem with Multiple Commensurate Objectives

The focus of this paper is to develop a solution framework to study equilibrium transportation network design problems with multiple objectives that are mutually commensurate. Objective parameterization, or scalarization, forms the core idea of this solution approach, by which a multi-objective problem can be equivalently addressed by tackling a series of single-objective problems. In particular, we develop a parameterization-based heuristic that resembles an iterative divide-and-conquer strategy to locate a Pareto-optimal solution in each divided range of commensurate parameters. Unlike its previous counterparts, the heuristic is capable of asymptotically exhausting the complete Pareto-optimal solution set and identifying parameter ranges that exclude any Pareto-optimal solution. Its algorithmic effectiveness and solution characteristics are justified by a set of numerical examples, from which we also gain additional insights about its solution generation behavior and the tradeoff between the computation cost and solution quality.     

Quality control of polymer production processes

For the polymer production industries, the competitive edge will come from the technology that excels in controlling the polymer properties in a consistent way over the entire plant and in maximizing the production performance while keeping safety regulations. Based on the experience in applying advanced process control and scheduling schemes to industrial polyolefin polymerization plants, the state of the art in quality control systems for providing the polymer production plant with an enlarged capacity for product discrimination and flexibility is reviewed. On-line soft-sensing and optimal grade changeover control problems are the main focus of this paper. A quality control system for polymer production plants, which integrates optimal control with on-line sensing and scheduling techniques, is discussed making reference to an application of a prototype system to an industrial plant.     

论高职化学多媒体课件教学

借助现代计算机多媒体技术制作适合高职教学的计算机多媒体系列课件,运用多媒体技术来扩充课堂容量,能突破教学重点和难点,保证教学按时和高质量地完成。基于此,该文就高职化学多媒体课件教学的有关问题展开论述。     

论高职化学多媒体课件教学

借助现代计算机多媒体技术制作适合高职教学的计算机多媒体系列课件,运用多媒体技术来扩充课堂容量,能突破教学重点和难点,保证教学按时和高质量地完成。基于此,该文就高职化学多媒体课件教学的有关问题展开论述。     

Hierarchical Capacity Planning With Reconfigurable Kits in Global Semiconductor Assembly and Test Manufacturing

Kits (such as accessories, fixtures, jigs, etc.) are widely used in production for many industries. They are normally product- and machine-specific, so a large kit inventory must be maintained when the product-mix variation is high. Fortunately, many kits are reconfigurable. That means they can be dissembled into components and then these components themselves (or together with some other components) can be reassembled into new types of kits. Therefore, we can save money and improve supply chain responsiveness by purchasing components instead of entire kits. However, research on capacity planning with reconfigurable kits has not been reported. We proposed a two-level hierarchical planning methodology to generate a complete capacity planning solution using mixed-integer linear programming. MaxIt covers mid-range monthly planning and automated capacity allocation system covers short-range weekly planning. These systems are integrated to generate optimal capacity plans considering kit components. This methodology has been successfully implemented in Intel's global semiconductor assembly and test manufacturing since 2004. In this paper, we present the hierarchical modeling framework and focus on MaxIt modeling with kit reconfiguration. We also verify the methodology by numerical experiments in a real production environment.     

Performance modeling of a two-echelon supply chain under different levels of upstream inventory information sharing

The advancement in information technology has facilitated the sharing of information in supply chain networks (SCNs), resulting in effective management of inventory and storage capacity. In this paper, our focus is on upstream inventory information sharing. Existing analytical performance evaluation models of SCNs are not capable of assessing the impact of inventory information sharing. To address this need, we develop performance evaluation models of SCNs that explicitly consider production capacity, inventory related decisions, variability, transit delays and inventory information sharing in a unified manner. We employ a two-echelon SCN configuration with two retail stores and two production facilities as a test bed. The retail stores have inventory information from the production facilities. We model three levels of inventory information sharing in our study; the information shared ranges from the stock-out information at the lowest level to inventory and backorder level information at the highest level. We develop analytical models first for Poisson arrivals and exponential processing times under all levels of inventory information sharing. We extend these models to general inter-arrival and processing time distributions and subsequently include transit delays between the production facilities and the retail stores. We demonstrate the performance prediction capability of the analytical models developed via extensive numerical experimentation.     

Lessons learned for building agile and flexible scheduling tool for turbulent environments in the extended enterprise

This paper presents results of a 2.5-year, multidisciplinary, university–industry collaborative effort investigating design of “Internet-based Scheduler for material Optimisation and agile ProducTion In MUlti-Site enterprises in agile manufacturing” (IS-OPTIMUS), a four nation collaborative project aimed at improvements in turbulent manufacturing environments. The focus of this paper is specifically on the content of the work carried out, along with the main benefits and results. Key to achieving the goals is following a complete project-life-cycle path from the initial stages where the industrial users requirements were identified and the system specification took place to the development and tuning of the final system. Design choices for software must strike a balance between the user flexibility required and the representing environment constraints, i.e. finite capacity scheduling, which takes production requirements from existing production planning systems, to schedule production resources like plant workers, critical tools and machines. The system consists of a material optimiser working closely with the finite capacity scheduler and a dynamic scheduler providing automatic reaction to real-time exceptions, thus deriving in solutions of higher performance.     

热电偶测量锅炉烟气温度的动态补偿方法

针对电站锅炉烟气温度测量中存在的显示数据动态误差问题．通过分析测量系统的动态模型及其频率响应特性，提出了烟温测量数值补偿方案和计算模型。经测试，系统的整体响应特性得到加快，解决了该系统的动态测量问题。     

基于进化博弈论的工业无线传感网能耗攻防研究

无线传感器节点由于部署、维护简单易行被广泛应用在工业网络中,并形成了工业无线传感器网络(Industrial Wireless Sensor Network,IWSN).针对在工业控制网络中的能量耗尽攻击的内部机理进行了详尽的分析,提出了基于进化博弈理论的能量耗尽攻防模型,将各个博弈方的收益函数定义为信誉值的函数,从而通过收益函数来约束博弈方的行为,并在理论上证明了该博弈的进化稳定策略的存在性.选取了策略选择概率作为算法的评价指标,设计并实施了大量仿真实验对算法进行验证.实验结果表明无论博弈双方的初始策略集概率分布如何,最终能达到有效防止能耗攻击的目的.     

Buffer allocation in flow-shop-type production systems with general arrival and service patterns

This study investigates the buffer allocation strategy of a flow-shop-type production system that possesses a given total amount of buffers and finite buffer capacity for each workstation as well as general interarrival and service times in order to optimize such system performances as minimizing work-in-process, cycle time and blocking probability, maximizing throughput, or their combinations. In theory, the buffer allocation problem is in itself a difficult NP-hard combinatorial optimization problem, it is made even more difficult by the fact that the objective function is not obtainable in closed form for interrelating the integer decision variables (i.e., buffer sizes) and the performance measures of the system. Therefore, the purpose of this paper is to present an effective design methodology for buffer allocation in the production system. Our design methodology uses a dynamic programming process along with the embedded approximate analytic procedure for computing system performance measures under a certain allocation strategy. Numerical experiments show that our design methodology can quickly and quite precisely seek out the optimal or sub-optimal allocation strategy for most production system patterns.Scope and purposeBuffer allocation is an important, yet intriguingly difficult issue in physical layout and location planning for production systems with finite floor space. Adequate allocation and placement of available buffers among workstations could help to reduce work-in-process, alleviate production system's congestion and even blocking, and smooth products manufacturing flow. In view of the problem complexity, we focus on flow-shop-type production systems with general arrival and service patterns as well as finite buffer capacity. The flow-shop-type lines, which usually involve with product-based layout, play an important role in mass production type of manufacturing process organization such as transfer line, batch flow line, etc. The purpose of this paper is to present a design methodology with heuristic search and imbedded analytic algorithm of system performances for obtaining the optimal or sub-optimal buffer allocation strategy. Successful use of this design methodology would improve the production efficiency and effectiveness of flow-shop-type production systems.     

FCS在制氧工艺中的应用

针对制氧工艺监控点较分散、控制回路较多的特点,采用SIEMENS PCS7控制系统,实现了生产过程的集中控制.对于压缩机存在的喘振现象,分析了喘振产生的原因和喘振的机理,提出了一种基于规则的工作点跟踪防喘振控制算法,有效地防止了喘振的发生,减少了因放空阀提前打开而造成的能量损失.在制氧过程中,分子筛吸附、再生的切换是空气纯化的核心流程,切换既要严格按照工艺要求进行,又要能够在特殊的情况下灵活地进行更改,采用PCS7中的SFC编程语言实现切换的顺控,完全满足了生产要求.     

光纤传输设计中的距离计算

光纤通信系统性能受光纤带宽及其传输损耗的影响,而光纤的传输损耗特性是决定光纤网络传输距离、传输稳定性和可靠性的最重要因素之一。针对上述问题,文章在对光：纤链路损耗进行分析的的基础上,给出了光纤传输距离计算的方法。     

基于WAP的手机图像处理系统的设计与实现

日益增长的对实时大容量的图像处理服务的需求使得手机图像处理系统成为人们关注的热点。文章阐述了手机图像处理系统结构设计以及WAP与MISC的接口设计,介绍了程序接口通信方式及协议说明、产品资源平台设计和系统部署,给出了开发手机图像智能处理系统的设计方法。     

基于和声搜索的环控通风调控策略优化

针对地铁车站环控通风系统风机定频运行,导致风机无法跟随站台PM2.5的浓度的变化而改变频率,造成能源浪费。根据环控通风系统的运行现状,可将其划分为只送不排模式、不送只排模式和即送又排模式,并考虑到环控通风系统应适应多扰动的影响,选取最小二乘法系统辨识一阶惯性时滞模型,用于描述变量动态变化响应传递函数,采用自抗扰控制器建立环控通风系统控制模型,利用和声搜索算法对环控通风模型PM2.5浓度设定值寻优,结果显示经过策略优化之后,只送不排模式、不送只排模式和即送又排模式站台PM2.5平均浓度分别降低了7%、8%和10%,风机能耗分别降低了19%、19%和30%。     

DPP: An agent-based approach for distributed process planning

A changing shop floor environment characterized by larger variety of products in smaller batch sizes requires creating an intelligent and dynamic process planning system that is responsive and adaptive to the rapid adjustment of production capacity and functionality. In response to the requirement, this research proposes a new methodology of distributed process planning (DPP). The primary focus of this paper is on the architecture of the new process planning approach, using multi-agent negotiation and cooperation. The secondary focus is on the other supporting technologies such as machining feature-based planning and function block-based control. Different from traditional methods, the proposed approach uses two-level decision-making—supervisory planning and operation planning. The former focuses on product data analysis, machine selection, and machining sequence planning, while the latter considers the detailed working steps of the machining operations inside of each process plan and is accomplished by intelligent NC controllers. By the nature of decentralization, the DPP shows promise of improving system performance within the continually changing shop floor environment.     

自卸式移动矸石仓的设计及应用

介绍了自卸式移动矸石仓的设计及其在国投河南新能开发有限公司的应用情况,重点介绍了自卸式移动矸石仓的箱体、刮板输送装置及转向行走机构的设计。实际应用表明,自卸式移动矸石仓可以有效地缓解巷道掘进时排矸难的问题,提高排矸速度和掘进进尺。     

Distributed adaptive control of production scheduling and machine capacity

This paper considers modeling and simulation of a unified control system that uses a continuous control-theoretic approach for distributed production scheduling at the shop floor and machine capacity control at the CNC level. Specifically, a distributed production scheduling method is unified with a distributed machine capacity control to generate realistic schedules considering the available capacity of production resources. In this distributed control system, machine capacity is adaptively controlled based on current physical conditions of the production resources and changes in production demands at the shop-floor level as well. The proposed system considers a multi-attribute objective that consists of production rate and product quality, production cost, and mean-squared deviation of job completions about due dates. The results obtained from the computational experiments show that the proposed system can improve the system performance through fully utilizing machine capacity while reducing production costs, production delays, missed deliveries, and customer dissatisfaction.     

The throughput rate of serial production lines with deterministic process times and random setups: Markovian models and applications to semiconductor manufacturing

We conduct exact analysis of serial production lines with deterministic service durations and various classes of random state-dependent setups between customers. Our focus is on assessing the production rate, or just-in-time (JIT) throughput. We demonstrate that such systems can be modeled as a Markov chain and consider various types of setups inspired by clustered photolithography tools in semiconductor manufacturing. We deduce when exact closed form expressions for the production rate are possible and when a numeric solution to the Markov chain balance equations are required. As these systems have shown promise for modeling process bound clustered photolithography tools, we study their accuracy versus detailed simulation for predicting the tool throughput. Various practical features such as the capacity of a pre-scan buffer and batch customers (to model wafer lots) are investigated.     

基于ARM的通风柜控制系统

化学实验室需要排放实验产生的有毒有害气体,并保证实验室内的正常空气压力和室内热量。本文介绍了某高校化学实验室通风控制系统的设计,详细说明了排风柜控制器和补风控制器的硬件和软件设计,为实验室排风系统提供了思路和方法。