基于约束理论的制造业高级计划排程模型的建立及应用

本文主要研究离散制造业普遍存在的生产计划排产问题,引入了高级计划排程(APS)概念,通过分析并应用其核心思想——约束理论指出其相对优势,并用线性规划算法来构建基于设备加工能力的高级排产模型,并在此基础上通过实例,进一步说明计划排程优化的应用。     

基于平均电价的在线电动汽车充电排程定价机制北大核心CSCDCSSCI

考虑在一个区域内单个充电站为多辆电动汽车(充电顾客)提供充电服务的排程与定价问题.充电顾客的排程(排序)有三种可选择的机制,即从高到低将待充电顾客按下列准则进行排序:1)顾客充电的总报价;2)顾客充电的单位报价;3)顾客在当前时间点之前已充电量的价值.基于上述充电排程机制,提出了一种基于顾客已充电量的平均电价且不依赖未来充电需求的定价机制,证明了所提出的排程定价机制具有个体理性和激励兼容特性.与已有的按顾客获得的最后一单位待充电价格进行定价的方法相比,研究发现:在第1)或第2)种排程机制下,所提出的定价机制顾客充电最终支付价格的期望相同,但方差减小;在第3)种排程机制下,所提出的定价机制顾客最终支付价格的期望和方差均减小.算例结果展示了所提出定价机制在减小充电顾客最终支付价格不确定性方面的作用与效果.     

基于平均电价的在线电动汽车充电排程定价机制

考虑在一个区域内单个充电站为多辆电动汽车(充电顾客)提供充电服务的排程与定价问题.充电顾客的排程(排序)有三种可选择的机制,即从高到低将待充电顾客按下列准则进行排序:1)顾客充电的总报价;2)顾客充电的单位报价;3)顾客在当前时间点之前已充电量的价值.基于上述充电排程机制,提出了一种基于顾客已充电量的平均电价且不依赖未来充电需求的定价机制,证明了所提出的排程定价机制具有个体理性和激励兼容特性.与已有的按顾客获得的最后一单位待充电价格进行定价的方法相比,研究发现:在第1)或第2)种排程机制下,所提出的定价机制顾客充电最终支付价格的期望相同,但方差减小;在第3)种排程机制下,所提出的定价机制顾客最终支付价格的期望和方差均减小.算例结果展示了所提出定价机制在减小充电顾客最终支付价格不确定性方面的作用与效果.     

炼钢-连铸生产进度控制系统的研究

有效的炼钢-连铸生产进度控制系统对钢铁企业提高生产率具有重要意义。本文针对某大型钢铁公司炼钢连铸生产调度问题,提出了具有该公司工艺特点的排程模型,结合由设备、工件、订单引起的动态事件,开发出进度控制系统。经实际数据测试,证明了算法的有效性和控制系统的实用性。     

基于TOC约束的工程机械行业生产计划管理系统研究

本文根据工程机械行业的现状,结合TOC约束理论和工程机械行业的生产特点,分析工程机械行业计划管理的特点和现状,重点对TOC约束下的工程机械行业生产计划、能力平衡、生产排程、配送管理等进行分析和阐述,提出工程机械行业的生产计划管理模式和方案.     

考虑交货因素的热轧无缝钢管订单排程模型与算法

无缝钢管的市场需求具有多品种、小批量的特点，为了在满足客户需求的同时保证高效连续化生产，文章在满足生产工艺特征的基础上将配送地址和交货期等合同因素引入热轧无缝钢管订单排程问题中，建立了以适期交货、订单集中生产配送和最小化机器设备调整为优化目标的订单排程优化模型，并设计了两阶段求解算法：首先，以订单交货期与配送地址差异最小为目标，基于凝聚策略设计了订单聚类算法，将具有相同工艺约束、相似合同要求的订单进行聚类，并形成初始轧制计划；然后，以设备调整和提前/拖期最小为目标，设计混合变邻域搜索算法，对初始轧制批次进行排程优化。基于实际订单数据的实验结果表明，模型和算法对问题的描述和求解是可行有效的。     

钢铁行业高级规划与排程系统研究

企业资源计划(ERP)一直是钢铁业管理信息化的热点,ERP虽然可以实现资源的整合,但其在生产计划领域的不足却难以提供高质量的生产计划方案。本文针对钢铁行业高级规划与排程系统的特点进行研究,指出APS与ERP的整合是钢铁行业未来信息化的发展方向。     

考虑随机且可控提前期的时基补货发货策略

研究了随机且可控提前期情况下"库存补货与运输排程"(SRSS)的时基补货发货策略,在"允许缺货,缺货不补"的传统假设基础上,结合使用随机过程更新理论和优化方法,建立了扩展模型;使用仿真方法跟踪了优化策略的长期执行效果,以验证模型有效性.     

基于APS的钢铁企业生产计划系统设计及实现

本文以高级计划排程系统(APS)理论为基础,对钢铁生产计划系统的总体结构和功能需求进行了分析和界定,设计了基于.NET三层客户端/服务器模式的钢铁企业生产计划系统,实现了生产计划管理中生产工单接收、计划排程、批量计划管理等核心功能.系统以承钢1780热轧卷板生产线为背景进行仿真验证,仿真结果表明,系统能够有效地提高生产计划管理效率,达到了预期的目的.     

炼钢连铸计划调度优化系统

钢铁企业的炼钢连铸计划调度问题一直是学术界和企业界研究的热门课题.炼钢连铸生产计划调度系统是钢铁企业制造执行系统的重要组成部分,在企业的生产管理中起着承上启下的作用.本文首先简述了炼钢连铸计划调度理论的发展历程和生产工艺流程,并进一步描述了炼钢连铸计划编制的流程.针对炼钢连铸计划调度的现场要求,架构了炼钢连铸计划调度优化系统的功能模块,并较详细地说明了各功能模块的功能特点.该系统不仅能对静态调度计划应用多种优化方法进行编制,而且对复杂生产环境的各类响应事件可以做到快速响应,满足动态调度的要求,保证生产的稳定顺行.     

Reducing Boarding in a Post‐Anesthesia Care Unit

When operating room schedules in hospitals are produced, the constraints and preferences of surgeons and hospital workers are a primary consideration. The downstream impact on post‐operative bed availability is often ignored. This can lead to the boarding of patients overnight in the post‐anesthesia care unit (PACU) because intensive care unit beds are unavailable. In this paper, we apply integer programming and simulation to develop improved surgical scheduling assignments. We want to balance new surgeries with hospital discharges in order to reduce the variability of occupied beds from one day to the next and, as a result, to reduce boarding in the PACU.     

Development and implementation of an operating room scheduling tool: an action research study

In this study, we report the results of an action research project whose aim was to develop and implement an operating room scheduler at the Meyer University Children’s Hospital. The study offers insights into the features that make an MSS optimisation model and scheduler effective and easy to implement, and shed light on those actions facilitating their introduction and use. Specifically, it suggests that creating an effective operating room scheduler requires clustering patients in homogeneous surgery groups and developing a flexible tool that allows: scheduling surgery groups instead of actual patients, easily adding/removing constraints, changing the objective function(s) and adjusting the planning horizon. In addition, it posits that gaining the commitment of top management by showing credible preliminary results, inferring stakeholder preferences by letting them comment on tentative schedules, introducing changes gradually and involving staff at lower levels of the hospital hierarchy can significantly facilitate the scheduler development and implementation.     

基于混合流水作业组织的集装箱码头装卸作业集成调度优化

集装箱码头集疏运资源调度的对象是由岸桥、集卡、场桥所构成的多阶段一体化的集装箱装、卸、运操作系统,将该系统的调度优化基于多阶段混合流水线调度问题建立混合整数规划模型,同时考虑集装箱码头现实作业中预定义顺序、避免岸桥交叉作业、以及取决于作业顺序的切换时间等现实约束,针对问题自身的特点设计了两阶段启发式算法,得出各阶段设备的指派结果及作业顺序。通过与基于现行调度规则的调度方案以及与目标函数理论下界值的对比实验,显示了所提出的集成调度模型及求解算法能够有效降低船舶在港时间并实现集卡资源的共享,为集装箱码头集疏运资源的集成调度提供了新的思路。     

Scheduling professionals in the retail pharmacy chain

To control operating costs, a zero-one integer programming model is developed to assist pharmacy staff scheduling decisions. Variable scheduling needs are met by the assignment of relief (mobile) pharmacists to help or temporarily replace full-time pharmacists. Assignments of relief pharmacists over a two-week planning horizon are determined with consideration given to variations in wage rates and travel costs together with the underlying corporate, contractual and operating constraints. The developed model has been applied with considerable success using data collected from a business district in the US located in northern Louisiana related to a national retail chain pharmacy. Forecasting the number of chain retail outlets in the near future has been also performed and the results obtained argue in favor of adopting the model by the entire chain.     

Reducing Surgical Ward Congestion Through Improved Surgical Scheduling and Uncapacitated Simulation

High surgical bed occupancy levels often result in heightened staff stress, frequent surgical cancellations, and long surgical wait times. This congestion is in part attributable to surgical scheduling practices, which often focus on the efficient use of operating rooms but ignore resulting downstream bed utilization. This paper describes a transparent and portable approach to improve scheduling practices, which combines a Monte Carlo simulation model and a mixed integer programming (MIP) model. For a specified surgical schedule, the simulation samples from historical case records and predicts bed requirements assuming no resource constraints. The MIP model complements the simulation model by scheduling both surgeon blocks and patient types to reduce peak bed occupancies. Scheduling guidelines were developed from the optimized schedules to provide surgical planners with a simple and implementable alternative to the MIP model. This approach has been tested and delivered to planners in a health authority in British Columbia, Canada. The models have been used to propose new surgical schedules and to evaluate the impact of proposed system changes on ward congestion.     

Supply chain scheduling optimisation in mass customisation based on dynamic profit preference and application case study

Traditionally, the ‘postponement strategy’ is a better way to solve the contradiction between ‘scale production effect’ and ‘customised demand level’ in mass customisation (MC). In higher customisation situation, the conflict between the role of postponement and the higher level of customised demand must be outstanding. When MC operates in supply chain, the excellent flexible characters of the supply chain system will create better conditions to solve the conflict from a new perspective, but the operating combination of MC and the supply chain with uncertain characters will lead to various complicated contradictions and bottlenecks. In this article, we discuss the supply chain scheduling optimisation in MC based on dynamic profit preference to solve these contradictions and bottlenecks, establish a special optimisation model to implement the scheduling. We make a computational industrial case study to illustrate the method application and show the benefits of solving the key contradiction in MC by the supply chain scheduling.     

A framework for studying practical production scheduling

The aim of this paper is to present what we believe are the most relevant findings and results regarding practical scheduling in order to define practical production scheduling and create a framework that helps researchers to study the various topics that fall under the umbrella of practical production scheduling and to identify the current state of knowledge for each topic. Studies from different fields were analysed and included in this paper, contributing significant knowledge to build a definition of practical production scheduling. Finally, we discuss the applicability that scheduling, as a task, could have in real companies.     

A heuristic approach to n/ m job shop scheduling: fuzzy dynamic scheduling algorithms

n/m shop scheduling is a ‘ NP-Hard’ problem. Using conventional heuristic algorithms ( priority rules) only, it is almost impossible to achieve an optimal solution. Research has been carried out to improve the heuristic algorithms to give a near-optimal solution. This paper advocates a fuzzy logic based, dynamic scheduling algoridim aimed at achieving this goal. The concept of new membership functions is discussed in die algorithm as a link to connect several priority rules. The constraints to determine the membership function of jobs for a particular priority rule are established, and three membership functions are developed. In order to decide the weight vector of priority rules, an aggregate performance measure is suggested. The methodology for constructing the weight vector is discussed in detail. Experiments have been carried out using a simulation technique to validate the proposed scheduling algorithm.     

Truck scheduling for solid waste collection in the City of Porto Alegre, Brazil

This paper considers a truck scheduling problem in the context of solid waste collection in the City of Porto Alegre, Brazil. The problem consists of designing “good” daily truck schedules over a set of previously defined collection trips, on which the trucks collect solid waste in fixed routes and empty loads in one of several operational recycling facilities in the system. These facilities are managed by cooperatives whose members are poor and not part of the mainstream economy. The main objective is to minimize the total operating and fixed truck costs. We show that the problem can be modeled as a special case of the single-depot vehicle scheduling problem, which is polynomially solvable. However, due to the social benefits of the solid waste program, it is desirable to obtain balanced assignments of collection trips unloading their cargo at the recycling facilities. We prove that the truck scheduling problem considering balanced unloading is NP-hard. A heuristic approach, incorporating an auction algorithm and a dynamic penalty method, is designed to acquire a good solution. Finally, computational experiments are conducted on real data. The results show that the heuristic approach simultaneously reduces total costs and balances the number of trips assigned to each recycling facility.     

Beyond Patient Classification: Using Individual Patient Characteristics in Appointment Scheduling

Scheduling patients involves a trade‐off between the productivity of the service provider and customer service. This study considers how outpatient medical facilities can improve their appointment scheduling by incorporating individual patient information in the scheduling process. Specifically, we obtain data on patient characteristics and examination durations from a health clinic, describe how that data can be used to predict patient examination durations in the clinic's appointment scheduling system, and evaluate the benefit of using individual patient characteristics over a conventional classification method. Computational results illustrate this method of patient scheduling reduces an overall cost function comprised of patient wait time, physician idle time, and over time by up to 24.2%, particularly when patients are sequenced with short duration patients being scheduled first. Several environmental characteristics are found to play critical roles in determining the magnitude of the benefit, including patient punctuality, no‐show probability, the clinic duration, the appointment rule used for scheduling, and the ratio of the physician's idle time cost to the patient wait cost. We also detail and evaluate a practical procedure for using heterogeneous scheduling under a fixed schedule.