Integration of real options into short-term mine planning and production scheduling

Commodity prices have fallen sharply due to the global financial crisis. This has adversely affected the viability of some mining projects, including leading to the possibility of bankruptcy for some companies. These price falls reflect uncertainties and risks associated with mining projects. In recent years, much work has been published related to the application of real options pricing theory to value life-of-mine plans in response to long term financial uncertainty and risk. However, there are uncertainties and risks associated with medium/short-term mining operations. Real options theory can also be applied to tactical decisions involving uncertainties and risks. This paper will investigate the application of real options in the mining industry and present a methodology developed at University of Queensland, Australia, for integrating real options into medium/short-term mine planning and production scheduling. A case study will demonstrate the validity and usefulness of the methodology and techniques developed.

Stochastic optimization of mine production scheduling with uncertain ore/metal/waste supply

Optimization of long-term mine production scheduling in open pit mines deals with the management of cash flows, typically in the order of hundreds of millions of dollars. Conventional mine scheduling utilizes optimization methods that are not capable of accounting for inherent technical uncertainties such as uncertainty in the expected ore/metal supply from the underground, acknowledged to be the most critical factor. To integrate ore/metal uncertainty into the optimization of mine production scheduling a stochastic integer programming(SIP) formulation is tested at a copper deposit. The stochastic solution maximizes the economic value of a project and minimizes deviations from production targets in the presence of ore/metal uncertainty. Unlike the conventional approach, the SIP model accounts and manages risk in ore supply, leading to a mine production schedule with a 29% higher net present value than the schedule obtained from the conventional, industry-standard optimization approach, thus contributing to improving the management and sustainable utilization of mineral resources.

An MILP approach for detailed scheduling of oil depots along a multi-product pipeline

Oil depots along products pipelines are important components of the pipeline transportation system and down-stream markets.The operating costs of oil depots account for a large proportion of the total system’s operating costs.Meanwhile,oil depots and pipelines form an entire system,and each operation in a single oil depot may have influence on others.It is a tough job to make a scheduling plan when considering the factors of delivering contaminated oil and batches migration.So far,studies simultaneously considering operating constraints and contaminated oil issues are rare.Aiming at making a scheduling plan with the lowest operating costs,the paper establishes a mixed-integer linear programming model,considering a sequence of operations,such as delivery, export, blending,fractionating and exchanging operations,and batch property differences of the same oil as well as influence of batch migration on contaminated volume.Moreover,the paper verifies the linear relationship between oil concentration and blending capability by mathematical deduction.Finally,the model is successfully applied to one of the product pipelines in China and proved to be practical.

Process Planning and Scheduling Integration in an Open Manufacturing Environment

New open manufacturing environments have been proposed aiming at realizing more flexible distributed manufacturing paradigms,which can deal with not only dynamic changes in volume and variety of products,but also changes of machining equipments,dispersals of processing locations,and also with unscheduled disruptions.This research is to develop an integrated process planning and scheduling system,which is suited to this open,dynamic,distributed manufacturing environment.Multi-agent system(MAS)approaches are used for integration of manufacturing processing planning and scheduling in an open distributed manufacturing environment,in which process planning can be adjusted dynamically and manufacturing resources can increase/decrease according to the requirements.One kind of multi-level dynamic negotiated approaches to process planning and scheduling is presented for the integration of manufacturing process planning and scheduling.

Evaluation of Operation Flexibility and Operation Selection in Multi-agent Based Production Scheduling

Based on the concept of operation flexibility, we study the relationship among multiple operation sequences and provide a flexibility measure for operation sequences. A criterion is proposed to prioritize each operation (rather than sequence). Under the multi-agent architecture the criterion can be used to guide the decision-making procedure during production scheduling so that there is an adequate flexibility at each decision point. Experimental results demonstrate the efficiency of the criterion when it is used as a scheduling heuristic. It can increase flexibility of manufacturing systems, and consequently improve the performance of the systems.

Energy-efficient Approach to Minimizing the Energy Consumption in An Extended Job-shop Scheduling Problem

The traditional production planning and scheduling problems consider performance indicators like time, cost and quality as optimization objectives in manufacturing processes. However, environmentally-friendly factors like energy consumption of production have not been completely taken into consideration. Against this background, this paper addresses an approach to modify a given schedule generated by a production plarming and scheduling system in a job shop floor, where machine tools can work at different cutting speeds. It can adjust the cutting speeds of the operations while keeping the original assignment and processing sequence of operations of each job fixed in order to obtain energy savings. First, the proposed approach, based on a mixed integer programming mathematical model, changes the total idle time of the given schedule to minimize energy consumption in the job shop floor while accepting the optimal solution of the scheduling objective, makespan. Then, a genetic-simulated annealing algorithm is used to explore the optimal solution due to the fact that the problem is strongly NP-hard. Finally, the effectiveness of the approach is performed small- and large-size instances, respectively. The experimental results show that the approach can save 5%-10% of the average energy consumption while accepting the optimal solution of the makespan in small-size instances. In addition, the average maximum energy saving ratio can reach to 13%. And it can save approximately 1%-4% of the average energy consumption and approximately 2.4% of the average maximum energy while accepting the near-optimal solution of the makespan in large-size instances. The proposed research provides an interesting point to explore an energy-aware schedule optimization for a traditional production planning and scheduling problem.

面向并行工程的CAD/CAPP/PPS集成研究

应用并行工程的思想 ,在对传统串行 CAD、CAPP及 PPS过程进行详细分析细化的基础上进行并行化重组 ,给出了 CAD/ CA PP/ PPS集成化过程模型 ,并分别对基于 PDM的 CAD/ CAPP集成和基于动态资源管理的CA PP/ PPS集成进行研究。本文的研究思想在国家 86 3计划南京金城集团 CIMS二期并行工程实施中得到应用 。

A STEP Based Integrated System for Assembly Planning and Design

An integrated system for assembly planning and design (INSAPS) is presented in which product data can be exchanged between assembly planning and assembly design on the basis of standard for exchange of product data model (STEP). The system consists of CAD system, product modeling system, assembly planning system. The product model is organized according to the STEP, uses mostly the entities of IR (integrated resources) and partly self defined entities which is necessary for assembly planning. A simple method of assembly sequence generation is presented which is suitable for complex assembly planning. The generated assembly sequences are evaluated considering the optimization of total assembly time. The results of assembly planning are feedback to the stage of assembly design to improve design.

Potential gains from spatially-explicit coordinated planning between two large public ownerships in Minnesota

Background: Many forested landscapes throughout the world involve a mix of public forest ownerships. This study explores how coordinated planning between two large public ownerships in Minnesota impact landscape-level trade-offs between timber production and production of core area of older forest (COF) for the region. COF is an important metric for wildlife habitat. Emphasis is on better understanding potential gains from both coordinated planning at the site-level where ownerships share stand boundaries and from coordinated planning at a broader policy level involving assumed values of COF by the public. The study area involves over 300,000 ha, 150,000 analysis units and a 100-year planning horizon. Methods: The concept of influence zones in modeling spatial interdependencies is described and implemented. The estimated total area of COF is assumed an important landscape metric for forest wildlife habitat condition for each forest planning period. COF has a surrounding buffer protecting it from edge effects. Differences are recognized between COF condition requirements and condition requirements for its surrounding buffer. A spatially-explicit harvest scheduling model is applied in conjunction with moving-windows techniques of GIS to find near-optimal management schedules for the large landscape. Multiple model runs are examined to help better understand both potential gains from coordinated planning and the tradeoffs between timber and COF production. Results: Results demonstrate the ability to incorporate detailed site-level COF production into management scheduling models for broad, landscape-level planning. For the study area and the assumed COF definitions, substantially larger gains are possible by coordinating COF value assumptions across ownerships, as compared to possible gains from coordinating on-the-ground management activities in areas involving shared stand boundaries. Although a general map of the study area shows a definite intertwining mosaic of ownership by the two large public agencies, a detailed breakdown of influence zone information shows that a low percentage of the land is influenced by both of these ownerships for COF production. Conclusions: This research helps illuminate potential large gains from coordinated planning at a broad policy level by large public ownerships through coordination of assumed COF values. For the study area, these gains are substantially greater than gains from combined modeling efforts addressing spatial detail and shared stand boundaries or neighborhoods. From a practical standpoint, this is important, as spatial detail adds substantially to model size, making combined analysis a major undertaking. Detailed site-level coordination also presents operational challenges in schedule implementation.

遗传算法在柔性CAPP与生产调度集成中的应用

提出了在并行工程思想下柔性CAPP与生产调度集成的框架 ,研究了遗传算法在柔性CAPP与生产调度集成中的应用方法。使用结构化编码方式对染色体进行编码 ,并应用规划 -资源算子进行遗传操作 ,通过使用重迭调度缩短了系统的流通时间。最后 ,算例验证了应用遗传算法的集成方法能够提高系统的全局优化和生产效率。

面向生产调度的柔性CAPP系统

这里重点分析了工艺规划对生产调度的影响,并提出了面向生产调度的工艺规划方案。在理论研究的基础上,设计出柔性CAPP的系统结构及功能模块。

基于O-O方法的CAPP系统制造资源结构建模

采用O-O技术建模方法,分析了制造资源各组成因素之间的关系、层次分类表示形式,以及制造资源与工艺能力生成之间的密切关系,建立了面向对象的制造资源结构模型,并对制造资源与生产规划调度PPS的关系模型进行了研究。

A framework for ICT-enabled real-time production planning and control

This paper aims to develop a conceptual framework for real-time production planning and control（PPC）.Firstly,we discuss the most prominently applied contemporary information and communication technologies for PPC.Enterprise resource planning（ERP） systems that integrate the value chain in an enterprise,manufacturing execution systems that manage and control the production on shopfloor,and advanced planning and scheduling（APS）systems that develop solutions for complex planning problems are the planning and control systems that have been analyzed.We emphasize the application of radio frequency identification as the most advanced and promising emerging real-time data capture technology that is currently available to manufacturers.Having analyzed the features and shortcomings of the individual systems perse,and by considering the advantages that may be realized through effective integration of these otherwise discrete systems,we propose a framework for real-time PPC.

A maintenance driven scheduling cockpit for integrated production and maintenance operation schedule

The production and maintenance functions have objectives that are often in contrast and it is essential for management to ensure that their activities are carried out synergistically,to ensure the maximum efficiency of the production plant as well as the minimization of management costs.The current evolution of ICT technologies and maintenance strategies in the industrial field is making possible a greater integration between production and maintenance.This work addresses this challenge by combining theknowledge of the data collected from physical assets for predictive maintenance management with the possibility of dynamic simulate the future behaviour of the manufacturing system through a digital twin for optimal management of maintenance interventions.The paper,indeed,presents a supporting digital cockpit for production and maintenance integrated scheduling.Thetool proposes an innovative approach to manage health data from machines being in any production system and provides support to compare the information about their remaining useful life(RUL)with the respective production schedule.The maintenancedriven schedulingcockpit(MDSC)offers,indeed,a supporting decision tool for the maintenance strategy to be implemented that can help production and maintenance managers in the optimal scheduling of preventive maintenance interventions based on RUL estimation.The simulation is performed by varying the production schedule with the maintenance tasks involvement;opportune decisions are taken evaluating the total costs related to the simulated strategy and the impact on the production schedule.

Application of EPNSim Graph in Making Simulation Models for an Integrated Steelmaking-Casting-Rolling

The EPNSim Graph was used to establish simulation models for an integrated steelmaking-casting-rolling production system.The simulation software was developed on the basis of the EPNSim Graph models and some production plans have been simulated with the software.The simulation results proved that the model established by EPNSim Graph is reliable.

一种基于设计结构矩阵的车间机床调度方法

为了解决制造企业内部加工机床合理排产问题,提出了一种基于设计结构矩阵(design structure matrix,DSM)的车间机床调度方法。构建了零件工艺与车间机床之间的关联矩阵调度模型;采用矩阵遍历算法,实现了加工机床根据待加工零件的工序信息自动合理分配机床;提出了最优机床排产方案评价指标、准则,采用多属性决策方法解决了最优机床排产方案的选择问题;通过开发的原型系统,实例验证了本文提出方法的可行性。

基于生产计划协同的商品车海铁联运班列开行方案优化研究

在物流业制造业深度融合创新发展的背景下,编制列车开行方案的同时考虑与主机厂生产计划的协同配合对推动商品车海铁联运高质量发展有着重要意义。为助力主机厂精益化管理、促进商品车海铁联运降本增效,从优化商品车海铁联运各环节衔接的角度出发,基于主机厂生产计划特点和海铁联运作业流程,综合考虑海运船期、班列开行方案和主机厂生产计划的协同配合,研究商品车海铁联运班列开行方案的优化方法。在构建商品车海铁联运动态运输服务网络的基础上,假设一定决策周期内生产计划和备选船期已知,以最小化海铁联运系统总物流成本为目标,以网络流平衡、弧段能力和班列编组数量要求等为约束条件,建立班列开行方案的优化模型,确定决策周期内班列开行方案和对接船期的选择。选取商品车海铁联运典型案例进行求解验证和灵敏度分析,并与原模式下船期确定和产运分离两个情景进行比较分析。由重庆鱼嘴站—广州港的商品车海铁联运案例分析可知,协同生产计划模式下的目标函数值对比船期确定情景和产运分离情景分别降低了147 400元和80 500元,并在一定程度上改善了运输时效。算例结果表明,在组织商品车海铁联运时将主机厂生产计划纳入考虑能够有效降低物流成本,提高运输效率;所提模型能够为海铁联运班列的开行方案决策提供有效参考。

经编车间高级计划排程系统及调度算法

多品种、小批量、订单化生产已成为纺织行业新常态,为解决现有管理模式与大规模柔性定制管理之间的矛盾,提出基于微服务架构的高级计划与排程(APS)系统,建立APS系统架构体系和功能模块,并基于APS系统的生产计划与调度运行机制,构建考虑最大完工时间和原料更换次数的多目标经编车间调度模型,采用非支配排序遗传算法(NSGA-Ⅱ)加以优化。结果表明:提出的APS系统能够有效地提高经编车间的生产效率,降低生产成本,缩短生产周期和交货期,满足客户需求和市场变化,为纺织生产企业的数字化升级提供了一种可行的解决方案。

基于MES的某型产线APS系统设计与开发

传统的基于人工的排产、调度和统计的生产模式,在计划编排、生产异常扰动调整及生产进度追踪等方面已无法满足当前实际生产需求。高级计划与排程(APS)系统能够针对有限的生产资源约束,为生产任务精确调配车间生产资源和生产时间,为复杂的生产和供应问题找出最优化的解决方法,确保生产资源的充分合理应用。针对某产线的实际业务需求和工艺流程特点,在制造执行(MES)系统基础上,设计了一种基于MES的APS系统。考虑了生产异常扰动、多工序连续生产、工序资源关联等因素,将生产计划细化至工序级,有效地解决了人工计划排程难度大、生产异常响应慢、排程结果不准确等问题,提高了生产效率。