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.     

Hierarchical scheduling in an intelligent environmental control system

This paper describes the design and implementation of a hierarchical scheduling subsystem and graphical user interface in an intelligent environmental control system. The hierarchical scheduling system is capable of managing all environmental events occurring in widely different time scales as specified by the user. We employ a knowledge representation scheme called a system entity structure to specify the environmental schedules in a hierarchical fashion. A system entity structure called TAL (Timed Action Language) is developed. TAL organizes a family of all possible long-/mid-/short-term schedules from which a specific schedule can be pruned by the user through graphical interface.Research was done while the author was a member of the Environmental Research Lab, University of Arizona. A Preliminary version of the paper was presented at 2nd International Conference on Industrial & Engineering Applications of AI and Expert System [5].     

一类基于多Agent和分布式规则的敏捷生产调度

Agent范例为解决制造系统的敏捷生产调度问题提供了一条新途径,如何构建敏捷生产调度多Agent系统结构和Agent间的协调与生产调度机制,成为一个亟待解决的课题.本文阐述了一类基于多Agent和分布式规则构建敏捷生产调度的方法.首先通过基于功能分解的方法,给出了管理、资源和工件等三类Agent基本组件组成的分布式多Agent调度系统结构、Agent组件基本结构及定义.其次,利用基于分布式规则的方法,建立了Agent间的协调策略和调度机制,实现了敏捷生产调度.最后给出了应用此方法的调度仿真实验结果.     

造纸企业多源数据融合算法与生产物流智能调度研究

为了有效地提高造纸企业智能调度的性能和效率,结合人工智能深度学习方法,针对造纸企业传感器数据融合探测、诊断决策和装载机调度等任务建立数据融合网络模型,提取数据的关联性特征,提高数据融合的精度和效率,并在此基础上开展生产物流智能调度研究。     

Expert systems in production planning and scheduling: A state-of-the-art survey

Intelligent solutions, based on expert systems, to solve problems in the field of production planning and scheduling are becoming more and more widespread nowadays. Especially the last decade has witnessed a growing number of manufacturing companies, including glass, oil, aerospace, computers, electronics, metal and chemical industries—to name just a few—interested in the applications of expert systems (ESs) in manufacturing. This paper is a state-of-the-art review of the use of ESs in the field of production planning and scheduling. The paper presents famous expert systems known in the literature and current applications, analyzes the relative benefits and concludes by sharing thoughts and estimations on ESs future prospects in this area.     

Team-based work and work system balance in the context of agile manufacturing

Manufacturing agility is the ability to prosper in an environment characterized by constant and unpredictable change. The purpose of this paper is to analyze team attributes necessary to facilitate agile manufacturing, and using Balance Theory as a framework, it evaluates the potential positive and negative impacts related to these team attributes that could alter the balance of work system elements and resulting "stress load" experienced by persons working on agile teams. Teams operating within the context of agile manufacturing are characterized as multifunctional, dynamic, cooperative, and virtual. A review of the literature relevant to each of these attributes is provided, as well as suggestions for future research.     

基于MAS的智能公交调度系统的建模与实现

城市公共交通具有结构复杂、并发性和分布性等特点,使用数学建模的方法很难有效解决其调度问题,而多Agent系统MAS是一种解决复杂系统问题的有效方式,因此应用MAS来解决公交调度问题。首先,建立了城市公交系统的概念模型;然后,根据MAS的建模思想对公交调度相关实体进行抽象,建立了智能公交调度系统的MAS模型,并给出了Dispatch Agent、Bus Agent和Stop Agent的建模方法以及知识库的构建、推理和学习的流程;最后,完成系统实现。     

呼叫中心智能排班系统关键技术

分析学习率和训练精度对BP神经网络训练最大次数、收敛时间和话务量预测精度的影响;根据呼叫中心历史话务量数据的日变化特点,提出并验证采用分时间段多次调用BP神经网络模型的方法比整体预测所得话务量预测结果精度更高;基于话务量预测结果,使用Erlang-C公式进行坐席数预测,结合呼叫中心的典型班次、设定的服务水平等参数进行坐席数曲线拟合,得到每个典型班次对应的话务员数量;开发呼叫中心智能排班系统,通过合理的排班实现大型呼叫中心资源的合理配置。     

敏捷供应链静态调度模型及其贪婪算法

针对确定性市场需求下的敏捷供应链(ASC)调度具有批量和时间双重约束的问题,根据供应层级关系建立多级供应链结构模型(SCSM),在此基础上设计调度问题的线性规划(LP)模型及其两阶段求解算法：第一阶段的最短响应时间调度贪婪算法判定供应链系统对需求批量和时间约束满足与否;第二阶段的精益调度贪婪算法求解以最小化供应链库存成本为目标的最优调度方案。最后通过算例验证了模型和算法的实用性和有效性。     

Shop-floor scheduling at shipbuilding yards using the multiple intelligent agent system

The intelligent agent system has become a typical approach to research distributed artificial intelligence and distributed problem solving. However, despite its various technical advantages, the distribution and expansion of the intelligent agent system approach has been limited because existing methodologies rely on specialized applications and therefore require intensive investment to develop new systems. In an attempt to conquer these difficulties, a standardized methodology to construct intelligent agent systems is proposed. This approach deviates from current agent system approaches of repeatedly constructing new and customized expert systems. Specifically, it provides an economical method for developing intelligent agent systems by investigating the possibility of standardizing message communication protocols in linguistics speech-act theory and by supplementing traditional algorithmic systems with intelligent segments using, among others, expert system tools. To verify effectiveness, the shop-floor scheduling system of a large-scale shipbuilding yard has been redesigned, developed, and tested using this approach. This shop-floor scheduling system requires the scheduling of when and where to process block construction under various constraints. It is a difficult four-dimensional time and space allocation problem involving traditional NP-complete search spaces. The tested intelligent agent system proposes an innovative method for reducing the search space into three levels: the algorithm level, the agent intelligence level, and the level of cooperation among agents. It also provides methods for solving deadlock occurrence and non-uniformity problems resulting from parallel processing. Test results demonstrate applicability and economy, among other technical advantages.     

基于改进遗传退火算法的生产智能调度系统

为了满足多品种小批量生产模式的需求,设计了一套基于智能调度算法的生产调度系统。根据数据的特点和系统的需求,设计了合理的数据结构和不同的调度规则;根据实际应用的要求,改进了遗传退火算法,使算法可以进行柔性调度和优先级调度,并且算法可以满足零件装配关系约束。在.NET3.5框架下,开发了生产智能调度系统,实现了对生产任务的智能调度。     

分布式嵌入式系统实时调度的建模

针对RBTPN模型在建模分布式嵌入式系统实时调度时的不足,提出了一种新的扩展时间Petri网模型。该模型通过在需要处理器资源的变迁上引入变迁速率因子,得到具有相同优先级变迁的运行速率函数,从而在分布式嵌入式系统的调度建模中,在单个处理器上结合了固定优先级可抢先调度和轮转调度。随后给出了该模型可达图的构造方法,以便可以得到调度序列的各种性质。     

矿井轨道运输智能调度系统设计

针对现有矿井轨道运输调度系统存在无法精确确定机车位置等问题,提出一种矿井轨道运输智能调度系统设计方案。该系统采用无线中继平台实现车地双向信息互换,采用射频识别技术实现机车精确定位,并可根据机车的速度和位置动态计算其运行时的安全间隔距离,实现移动闭锁,提高行车密度。     

A bio-inspired mobile agent-based integrated system for flexible autonomic job shop scheduling

This paper presents a bio-inspired mobile agent-based integrated system for flexible autonomic job shop scheduling. The system matches the autonomic system architecture, inspired by the autonomic nervous system and proposed by the IBM, and has the IBM-defined fundamental self-managing properties, so that it can manage itself with little human intervention. The system conforms to the IEEE FIPA (Foundation for Intelligent Physical Agents) standard. Therefore, the interoperability between agents of the system and agents from many active heterogeneous FIPA compliant agent platforms can be ensured. The system supports the execution of C/C++ mobile agent codes. Thus, it is applicable to a variety of applications, especially for distributed mechatronic and embedded systems. In addition, since the system is composed of agents, including stationary and mobile agents, the system has a high scalability and flexibility to integrate and adopt various scheduling models and algorithms for different scheduling requirements. An overall architecture of the system and critical implementation details about the agency and agents in the system are presented in this article. An energy saving job shop scheduling example is used to validate one autonomic property of the system.     

Developing a neural network approach for intelligent scheduling in GUESS

The generically used expert scheduling system (GUESS) intelligent scheduling toolkit has been built and applied in various scheduling domains. Previously, GUESS included three major scheduling approaches: a heuristic-based (suggestion tabulator) approach, a hill-climbing algorithm, and a genetic algorithm approach. GUESS has now been expanded to include a neural network scheduling approach. This paper discusses the development, implementation and testing results of the neural network scheduling method within GUESS.     

A knowledge-based system for reactive scheduling decision-making in FMS

This paper describes research into the development of an intelligent simulation environment. The environment was used to analyze reactive scheduling scenarios in a specific flexible manufacturing systems (FMS) configuration. Using data from a real FMS, simulation models were created to study the reactive scheduling problem and this work led to the concept of capturing instantaneous FMS status data as snapshot data for analysis. Various intelligent systems were developed and tested to asses their decision-making capabilities. The concepts of History Logging and expert system learning is proposed and these ideas are implemented into the environment to provide decision-making and control across a FMS schedule lifetime. This research proposes an approach for the analysis of reactive scheduling in an FMS. The approach and system that was subsequently developed was based on the principle of automated intelligent decision-making via knowledge elicitation from FMS status data, together with knowledge base augmentation to facilitate a learning ability based on past experiences.     

基于改进型批决策与调度建模的生产计划调度系统的研究

热轧型钢生产工艺复杂,其生产中极易出现由于计划调度安排不当而产生的交货期延误、库存超负荷等问题。针对以上问题研究设计了MES生产计划调度系统,改进了批决策调度策略用于数学建模,利用自适应遗传算法求解生产调度计划。以此为基础,为某热轧企业设计实现了生产计划调度系统,并通过真实的热轧型钢订单、原料、设备等数据,对模型改进前后的计划编制方法进行模拟与比较,验证了利用该改进型批决策与调度模型编制的热轧型钢生产调度计划可节省生产时间、降低设备调度时间,以此来指导热轧型钢的生产可切实减少交货延误和减少库存占用率,并提高企业利润率。     

基于仿真的生产计划与调度系统集成

针对航天制造企业和产品生产特点,描述了一个生产计划、仿真和调度集成系统.分析了该类型企业在生产管理上存在的主要问题,描述了集成系统的框架及主要组件的功能,以及集成系统的运行机制.该系统利用仿真技术将企业的生产计划与作业调度紧密集成,实现了计划部门与生产部门在信息和流程上的紧密关联.最后通过实例验证了该集成系统的可行性与有效性.     

间歇过程生产调度建模的研究

生产调度是为实现某一目的而对共同使用的资源进行时间上的分配.调度中存在大量的模糊因素,将模糊的思想运用到调度领域可以帮助决策者进行有效决策.本文提出一种基于模糊规划的间歇过程生产调度建模方法及其模糊优化的新算法.应用模糊集合论的方法,在已有模糊规划模型的基础上,针对间歇生产过程,分析调度中存在的模糊信息以及出现的形式和方式,将确定型生产调度模型的约束条件和目标方程中的参数模糊化,采用非精确的量化形式,以隶属函数来表示,建立基于模糊参数的生产调度模糊线性规划模型MIFCLP.通过对一个调度问题实例进行了仿真,仿真结果证明,采用模糊模型更容易得到可行解,采用模糊线性规划解决间歇生产调度问题是一种有效方法.     

基于工作流的分布式协同计划控制架构研究

从协同的角度研究了制造业在分布式协同制造企业环境下所面临的相关技术问题,提出了基于工作流的分布式协同计划控制架构。该架构分为两层,在企业层对所有协同机构的生产任务进行动态的协同优化调度;在车间层对有限资源在需求约束下进行优化调度。应用扩展的工作流概念和功能去正确地管理活动序列,建立了资源管理、活动调度以及任务协同调度的优化模型。最后,提出了基于规则的更新处理组件用于提高系统自动化程度。