The Value of Using Scheduling Information in Planning Material Requirements*

Current research and practice in the field of production and inventory planning is dominated by hierarchical, material requirements planning-based methods. The objective of this research is to determine the merits of a major redirection for the design of manufacturing planning systems—a direction that more directly exploits the capabilities of modern computer technology. We test the relative performance of two fundamentally different classes of manufacturing planning systems: (1) those that make no use of sequencing and scheduling information in the planning of material deliveries (for example, traditional MRP-based systems), and (2) those that use sequencing and scheduling information to plan delivery of materials. We first derive an analytical expression for the expected benefit (in terms of flow time reduction) of using scheduling information for a single machine system. We then describe and test a simple heuristic for predicting the improvement that could be realized in more complicated multimachine systems, under certain conditions. Results from controlled simulation experiments, over a wide range of operating environments, suggest that although the value of scheduling information is influenced by the operating environment, it could be substantial.     

Taxonomy of ERP integrations and performance outcomes: an exploratory study of manufacturing firms

Building and deploying network capabilities of firms are crucial for sustaining competitive advantage. Enterprise resource planning (ERP) systems are useful to enhance such network capabilities thorough effective information flows. Their intended goals are measured in terms of production costs, operational flexibility and supply chain performance outcomes. However, the impact of ERP system implementation on firm performance has been reported as somewhat inconclusive. This study contends that a missing link in the story is the scope and extent of ERP system implementation after investigating how the extent of ERP integration is associated with the performance outcomes of manufacturing firms. The study also posits that restructuring in the organisation and supply chains are positively associated with manufacturing performance. Since ERP often entails restructuring in an organisation and supply chains, it is anticipated that restructuring plays an important role in inducing positive impact of ERP implementation to the firm. Using a global sample of 641 manufacturers, this research identifies four distinct ERP systems integration patterns, epitomised by different extents and directions of integration, and finds a significant association among the broadest degree of ERP systems integration, restructuring and plant performance improvement. The empirical results also show that restructuring takes place most actively in a firm that implement ERP with widest scope and scale.     

Experimental push/pull production planning and control system

We introduce an experimental push/ pull production planning and control software system which is designed as an alternative to a MRP-II system for mass manufacturing enterprises in China. It has the following distinguishing features: (1) putting the philosophy of JIT into the master production scheduling of MRP-II via the earliness/ tardiness production planning method; (2) controlling material input by push and processing/ assembly by pull; and (3) adjusting the parameters of the production line by the‘ suggestion for improvement of production line’ module. Simulation results have shown that the proposed system can achieve better planning and control performance than existing systems.     

The impact of operations anticipations on the quality of stochastic location-allocation models

It is now a common practice to use optimization models, such as location-allocation models, to support the design of supply chain networks (SCN). The value creation potential of a SCN design must be evaluated in terms of capital expenditures, but also of the operating revenues and expenses incurred during the planning horizon considered. The design model used should therefore be formulated to anticipate these revenues and expenses (relatively) accurately over the planning horizon. In classical location-allocation models, the aggregate flow and throughput variables used yield very crude anticipations. It was never shown that they lead to the best SCN design that one should expect. This paper draws on the stochastic multi-period location-transportation problem (SMLTP) for studying the impact of various types of operations anticipations on the quality of the SCN designs obtained. Since accurate anticipations yield more complex models, solvability is also an issue. Several alternative SCN design models based on more detailed anticipations than the ones embedded in classical location-allocation models are proposed and tested. Accuracy-solvability trade-offs are explored and recommendations are made on the modeling strategy to use to get better SCN designs.     

Shop floor characteristics influencing the use of advanced planning and scheduling systems

The purpose of this article is to investigate how the manufacturing process, the shop type and the data quality, i.e. the shop floor characteristics, influence the use of advanced planning and scheduling (APS) systems in production activity and control (PAC). The methodology implemented is a multiple case study at three case companies. Each company has different shop floor characteristics, but all use a scheduling module in an APS system, which supports production scheduling. A theoretical framework is developed suggesting how APS system are used in the PAC activities, and which major aspect to consider. The case analysis shows that the scheduling module in APS system, foremost supports sequencing and dispatching. In particular, the shop type is influenced by the decision of how often the APS runs and what freedom is given to the shop floor. The manufacturing process influences how the dispatch list is created. Contrary to the literature presuming that APS systems are most suitable in job shop processes, it is found that the manufacturing process is not a crucial factor when deciding whether APS systems are an appropriate investment. It is found that the level of data quality needed in the APS system depends to a large extent on how the dispatch list is used. For example, is the dispatch list used as a guideline, not a regulation, the need for accurate data in the module is reduced. This article extends the previous literature concerning APS systems by analysing how APS systems influence PAC as a whole and increase the understanding of the challenges of using APS systems in PAC.     

PRACTICE‐FOCUSED RESEARCH ISSUES FOR SCHEDULING SYSTEMS*

Scheduling research has had relatively little impact on manufacturing practice, yet within the last several years, there has been an explosive growth in the development and implementation of computer‐based scheduling systems in industry. Changes in the environment have increased the stakes and the opportunities for the results of scheduling research to influence manufacturing competitiveness. This paper draws on field‐related experiences with the development and implementation of scheduling systems to propose high‐impact research topics.     

John A. Buzacott and His Pioneering Contributions to Manufacturing and Service Systems

John A. Buzacott is a pioneering and premier contributor to the field of production and operations management. He has been a principal architect of the development of a unified framework and a rigorous engineering foundation for many of the major approaches currently used in the design, planning, and control of manufacturing and service systems. His innovative use of stochastic models to explain many phenomena occurring in manufacturing and service organizations has distinguished him not only as a great researcher but also as a great teacher. His contributions have inspired scholars throughout the world. We provide an overview of John's research works and accomplishments.     

Load-oriented manufacturing control just-in-time production for job shops

The paper describes the principles of load-oriented manufacturing control as a new solution for job shops and its successful implementation in a pump-manufacturing factory. The idea of load-oriented manufacturing control is to limit and balance work-in-process inventory on a level as low as possible in order to accomplish a high work-centre utilization as well as a rapid and in-time flow of orders. As the new system keeps actual lead times on a planned level in a self-regulating way, it allows reliable due-date scheduling. Furthermore it points out the bottlenecks and performs applicable mid-term and short-term capacity planning.     

Operations in Financial Services—An Overview

We provide an overview of the state of the art in research on operations in financial services. We start by highlighting a number of specific operational features that differentiate financial services from other service industries, and discuss how these features affect the modeling of financial services. We then consider in more detail the various different research areas in financial services, namely systems design, performance analysis and productivity, forecasting, inventory and cash management, waiting line analysis for capacity planning, personnel scheduling, operational risk management, and pricing and revenue management. In the last section, we describe the most promising research directions for the near future.     

Performance of spare parts supply chains in developing industries

Spare parts supply chains of manufacturing equipment in developing industries such as the Saudi manufacturing sector often operate in one direction. Importing production machinery and setups to run such developing industries, from more developed industrial countries, sway the flow of spare supplies upstream. Based on empirical data collected from 210 local manufacturing firms, this study characterises and models such supply chains. The effects of supplier proximity, diversity and time lag on spare parts supply chain performance were explained using structural equation modelling. Delivery time lag and supplier diversity increased the deficiency of spare parts availability. Opposite to earlier consensus found in the literature, the impact of supplier proximity on spare parts supply chain performance was insignificant. Recent improvements in the agility and capacity of logistical services might have diminished the influence of supplier remoteness. However, supplier proximity correlated with supplier diversity in such supply chains.     

MASCOT: An agent-based architecture for dynamic supply chain creation and coordination in the internet economy

The emerging global internet economy will increasingly put a premium on the ability of companies to quickly and accurately evaluate new market opportunities, new product/ subcomponent designs, and other strategic business decisions (e.g. make-or-buy) in coordination with potential supply chain partners. It also requires that companies be able to effectively and efficiently coordinate activities, e.g. production and transportation across supply chains that are dynamically set up in response to constantly changing and increasingly customized market requirements. This paper provides an overview of MASCOT ('multi-agent supply chain cordination tool'), a reconfigurable, multi-level, agent-based planning and scheduling architecture aimed at supporting these functionalities. It reviews key innovative elements of the MASCOT architecture with a special emphasis on its support of realtime mixed-initiative 'what-if' functionalities, enabling endusers at different levels within the architecture to rapidly     

The Reverse Supply Chain Planning Matrix: A Classification Scheme for Planning Problems in Reverse Logistics

This paper presents a conceptual planning framework for reverse supply chain operations based on an extensive literature review and industry expertise. Such a holistic scheme for classification of planning tasks is necessary as the intensification of research on reverse logistics and closed‐loop supply chains in recent years has raised a number of planning problems that differ from those of solely forward‐oriented supply chains. Up to now, a common and comprehensive definition of relevant planning problems along the reverse chain has not existed. Thus, a thorough understanding of the interdependence between these elements is missing. This paper aims to systematically identify planning problems, which are assigned to different planning horizons and distinct process stages of product recovery. The result is a classification scheme, called a ‘Reverse Supply Chain Planning Matrix’ (RSCPM), which categorizes planning problems and shows their interrelation in recovery operations. It serves both academia and practitioners as a holistic overview for planning and decision tasks. Moreover, decision‐makers are supported in identifying the relevant variables in reverse supply chains and in revealing the consequences of one decision regarding other parameters of the system. To the best of the authors' knowledge, the RSCPM is the first attempt to comprehensively structure the field of reverse supply chain research by identifying, defining and interconnecting planning problems within an integrated framework, as is common in the forward case.     

Alternate Routing Strategies in Batch Manufacturing: An Evaluation

Batch manufacturing firms are experiencing significant changes because of technological developments in work center design, such as flexible manufacturing systems (FMS) and planning/control tools like computer-aided process planning (CAPP). These new developments provide production managers with some solutions to a number of complex problems. For example, numerical-controlled (NC) machine center installations are effective in providing quality parts because of tight tolerance specifications built into the equipment. However, these highly efficient centers create bottlenecks that constrain shop throughput, since production planners tend to rely too much on them. To help improve manufacturing planning, we introduce an important element to the batch production scheduling component of CAPP's mission—evaluating possible alternate routes. Production scheduling encompasses job route selection as well as machine center assignment (loading), job releasing, and setting due dates. In this paper, three routing strategies requiring different levels of shop floor information are tested and evaluated using computer simulation. Shop performance is measured by total cost and traditional measures of job flow time, lateness, and tardiness.     

Guest Editorial Production Planning and Control in other Industries

This paper provides an excursion into various scheduling problems arising in the manufacturing environment and possible approaches that can be taken to solve them. It reviews the research in production scheduling from the perspective of designing and operating a production system and examines the research strategies adopted to find the solution of the practical problems. This review is in the form of the paradigms that evolved during the twentieth century and shows the transition in theory and practice of each paradigm. It covers the fundamental frameworks of scheduling theory, outlining various approaches that can be taken to solve (optimally or approximately) such problems, and the difficulties arising in their practical use. Subsequently, an iterative scheduling process is suggested as an extension of existing paradigms to solve practical production scheduling problems and to bridge the gap between theory and practice in production scheduling and control.     

Literature review: Strategic network optimization models in waste reverse supply chains

In scientific literature two large, partly overlapping areas regarding the environmental and economical attractive removal of waste coexist: reverse logistics and waste management. Both fields study, among other topics, the flows of discarded products leaving the end consumer. This review takes an integrated point of view on reverse logistics and waste management and aims at a better integration. More specifically, it gives a concise but complete overview of the efforts already performed in the area of strategic network design in waste reverse supply chains by means of combinatorial optimization models. Its purpose is to guide interested readers and researchers directly to publications of their interest, and let them identify courses other than the well-worn paths. Among others, we explicitly refer to (1) the importance of environmental, social and performance indicators in multi-objective models, (2) the potential of incorporating the different waste reverse supply chain stakeholders into the network design model, (3) the consideration of future waste reverse supply chain developments like extended producer responsibility schemes and the circular economy and their challenges, and (4) better heuristics to deal with the increasingly complex strategic network design models.     

Tactical production and distribution planning with dependency issues on the production process

Tactical production-distribution planning models have attracted a great deal of attention in the past decades. In these models, production and distribution decisions are considered simultaneously such that the combined plans are more advantageous than the plans resolved in a hierarchical planning process. We consider a two-stage production process, where in the first stage raw materials are transformed into continuous resources that feed the discrete production of end products in the second stage. Moreover, the setup times and costs of resources depend on the sequence in which they are processed in the first stage. The minimum scheduling unit is the product family which consists of products sharing common resources and manufacturing processes. Based on different mathematical modelling approaches to the production in the first stage, we develop a sequence-oriented formulation and a product-oriented formulation, and propose decomposition-based heuristics to solve this problem efficiently. By considering these dependencies arising in practical production processes, our model can be applied to various industrial cases, such as the beverage industry or the steel industry. Computation tests on instances from an industrial application are provided at the end of the paper.     

A Modeling Framework for Supply Chain Simulation: Opportunities for Improved Decision Making*

Owing to its inherent modeling flexibility, simulation is often regarded as the proper means for supporting decision making on supply chain design. The ultimate success of supply chain simulation, however, is determined by a combination of the analyst's skills, the chain members' involvement, and the modeling capabilities of the simulation tool. This combination should provide the basis for a realistic simulation model, which is both transparent and complete. The need for transparency is especially strong for supply chains as they involve (semi)autonomous parties each having their own objectives. Mutual trust and model effectiveness are strongly influenced by the degree of completeness of each party's insight into the key decision variables. Ideally, visual interactive simulation models present an important communicative means for realizing the required overview and insight. Unfortunately, most models strongly focus on physical transactions, leaving key decision variables implicit for some or all of the parties involved. This especially applies to control structures, that is, the managers or systems responsible for control, their activities and their mutual attuning of these activities. Control elements are, for example, dispersed over the model, are not visualized, or form part of the time‐indexed scheduling of events. In this article, we propose an alternative approach that explicitly addresses the modeling of control structures. First, we will conduct a literature survey with the aim of listing simulation model qualities essential for supporting successful decision making on supply chain design. Next, we use this insight to define an object‐oriented modeling framework that facilitates supply chain simulation in a more realistic manner. This framework is meant to contribute to improved decision making in terms of recognizing and understanding opportunities for improved supply chain design. Finally, the use of the framework is illustrated by a case example concerning a supply chain for chilled salads.     

Resilience metrics in the assessment of complex supply-chains performance operating under demand uncertainty

The design and planning of resilient supply chains is a major challenge due to the increasing complexity of these systems that operate in a global market and therefore are more exposed to disruptions. In the present work a design and planning model that integrates demand uncertainty is applied to five supply chain structures that are submitted to different types of disruptions. Disruptions are modelled in a probabilistic manner, resulting in the incorporation of two sources of uncertainty. Eleven indicators are considered to assess the supply chains’ resilience, which comprise network design, centralization and operational indicators. The goal is to provide managers what are expected operational impacts (measured by the operational indicators) by assessing the behavior of network and centralization indicators and their known resilience behaviors from the literature. A case study of a European supply chain is used to illustrate the methodology and a discussion on the results obtained is presented in order to conclude which main characteristics a manager should consider when designing and planning resilient supply chains.     

大量定制环境下基于延迟制造的多级供应控制模型研究

针对大量定制环境下延迟制造活动的特点,提出将客户订单分离点(CODP)前移到供应商流程内部实现供应延迟,给出了基于延迟制造的多级供应控制生产计划模型,研究了面向多级供应控制的物料清单(BOM)和产品设计问题。