Vendor managed inventory in tramp shipping

This paper introduces a new problem to the OR community that combines traditional tramp shipping with a vendor managed inventory (VMI) service. Such a service may replace the more traditional contract of affreightment (COA) which for decades has been the standard agreement between a tramp shipping company and a charterer. We present a mathematical formulation describing the routing and scheduling problem faced by a tramp shipping company that offers a VMI service to its customers. The problem is formulated as an arc-flow model, and is then reformulated as a path-flow model which is solved using a hybrid approach that combines branch-and-price with a priori path-generation. To solve larger, and more realistic, instances we present a heuristic path-generation algorithm. Computational experiments show that the heuristic approach is much faster than the exact method, with insignificant reductions in solution quality. Further, we investigate the economic impact of introducing a VMI service, by comparing the results obtained with the new model with results obtained by solving the traditional routing and scheduling problem faced by tramp shipping companies using COA. The computational results show that it is possible to substantially increase supply chain profit and efficiency by replacing the traditional COAs with VMI services.     

Planning a sustainable reverse logistics system: Balancing costs with environmental and social concerns

The present work aims to support tactical and operational planning decisions of reverse logistics systems while considering economic, environmental and social objectives. In the literature, when addressing such systems economic aspects have been often used, while environmental concerns have emerged only recently. The social component is the one less studied and rarely the combination of the three concerns has been analyzed. This work considers the three objectives and was motivated by the challenge of supporting decision makers when managing a real case study of a recyclable waste collection system, where strategic decisions on the number and location of depots, vehicles and containers were taken beforehand. Tactical and operational decisions are studied involving the establishment of service areas for each depot and the definition and scheduling of collection routes for each vehicle. Such decisions should represent a compromise solution between the three objectives translating a sustainable reverse logistics plan. The problem is modeled as a multi-objective, multi-depot periodic vehicle routing problem with inter-depot routes. A mathematical formulation and a solution approach are proposed. An approximation to the Pareto front is obtained for the case study and the trade-offs between the objectives are discussed. A balanced solution is proposed.     

Organizing for strategic management— A conceptual model

Managing the strategic problems is a complex process. In order to organize this process efficiently in one's own company it is necessary to understand and be able to communicate the basic factors involved. In the author's view there is a need to compile into a model concepts, relations and organizational principles of major importance to successful strategic planning. This article is based on the author's analysis of current literature and his own practical experience in Scandinavia. The article presents a conceptual model for strategic management including the planning process as well as the execution of strategic decisions. This model is related to basic organizational principles and the methodology used in project management.     

How to integrate strategic planning into your management process

The primary purpose of strategic planning is to enable management to make decisions today which will affect the firm over the long run where the long run is characterized by risk and uncertainty. If strategic planning is to be useful to management it must be an integral part of the decision making process and not merely an appendage to the management process. In this paper we shall define some of the problems involved in integrating strategic planning and strategic planning tools into the decision process. We shall also suggest some possible solutions to these problems.     

A visual planning solution to streamline the processes of hybrid cross-dockings

Cross-docking is a logistic strategy widely adopted both in manufacturing and distribution contexts. Despite the huge number of researches on this topic, most of them remain rather theoretical as they do not pay enough attention to operational aspects and daily functioning patterns of cross-dockings. This article aims at introducing a new focus for cross-docking research by proposing a visual planning solution to manage daily operation of a manufacturing cross-docking. By avoiding complex optimization algorithms and by adopting concepts belonging to the lean management theory, the article shows the potential of visual planning techniques to improve performance of cross-dockings. Starting from a specific industrial context, the shipping warehouse of an Italian company of the oil andand gas sector, a visual management methodology has been proposed to support the operation of cross-dockings. Although developed in a particular context, the proposed methodology and its underlying principles are to be considered general and potentially applicable to a wide range of cross-dockings. The methodology fully exploits an analytical tool, namely, the Safety Margin coefficientthat could be used for capacity planning purposes and to evaluate quantitatively the system performance at a given time instant.     

Tighter MIP models for Barge Container Ship Routing

This paper addresses the problem of optimal planning of a liner service for a barge container shipping company. Given estimated weekly demands between pairs of ports, our goal is to determine the subset of ports to be called and the amount of containers to be shipped between each pair of ports, so as to maximize the profit of the shipping company. In order to save possible leasing or storage costs of empty containers at the respective ports, our approach takes into account the repositioning of empty containers. The line has to follow the outbound–inbound principle, starting from the port at the river mouth. We propose a novel integrated approach in which the shipping company can simultaneously optimize the route (along with repositioning of empty containers), the choice of the final port, length of the turnaround time and the size of its fleet. To solve this problem, a new mixed integer programming model is proposed. On the publicly available set of benchmark instances for barge container routing, we demonstrate that this model provides very tight dual bounds and significantly outperforms the existing approaches from the literature for splittable demands.We also show how to further improve this model by projecting out arc variables for modeling the shipping of empty containers. Our numerical study indicates that the latter model improves the computing times for the challenging case of unsplittable demands. We also study the impact of the turnaround time optimization on the total profit of the company.     

Understanding managers' preferences for internal markets versus business planning: A comparative study of German and U.S. managers

Internal markets and centralized business planning are alternative organizational designs for coordinating the economic activities within a firm. While some preliminary theory about when to use each exists in the literature, little is known about how managers understand and decide when to use one or the other. The study develops and tests in samples of German and U.S. managers a preliminary theory about factors that influence the preferences of managers for internal markets or planning as alternative modes of coordination. Managers' preferences are influenced by key constructs of internal markets and planning theory (the perceived limits of planning, speed and efficiency of markets, motivation potential of markets), but also by differences in their institutional contexts (national government and business context, company culture, and recent company experience with planning and internal markets). The study is the first to explore the substitutability of internal markets and planning within the strategic decision process of managers, closer to where it becomes reality.     

一种策略层项目计划的双目标优化方法

针对产品开发项目管理的实际情况,对策略层计划优化方法进行研究。以工作包的工作量估算为基础,以资源投入水平和工期最小化为目标,考虑各种约束条件,提出一种策略层项目计划问题的混合整数规划问题模型。以非支配遗传算法NSGA-II为基础框架,设计了一种改进的双目标遗传算法。该算法针对问题的特点,提出了基于资源平滑的解码算法。参考NSGA-III的关键特征,对拥挤密度计算方法进行改进。通过企业实际项目案例,验证了算法的性能和所提出的策略层项目计划方法的有效性。     

Engineering of a decision support system for underground coal mine planning and production scheduling

This paper reports on the development of a computer-based management information system at Datong Coal Company, the largest subsidiary of China National Coal Corporation. Particularly presented is the development methodology of a decision support system for underground coal mine planning and production scheduling, including an integration of computer graphics, database management, mathematical modelling and knowledge engineering techniques and a coupling of life cycle and prototyping software engineering processes to support systems quality assurance.     

航运供应链上的品牌价值、公平关切与契约协调

航运供应链上的船公司提高企业品牌价值需要付出大量的投资成本,因此将会更加关注供应链上利润分配的公平。本文以单个船公司和单个货代公司构成的两级航运供应链为研究对象,运用博弈论分析船公司的公平关切行为和品牌投入意愿对航运供应链上各方利润的影响,探讨决策者非理性条件下航运供应链的合作模式和协调机制。研究表明：1）船公司的公平关切提高了其在供应链上利润分配占比,但降低了整个航运供应链的利润和效率;2）随着品牌投入意愿的提高,船公司的公平关切对航运供应链上各方决策的负作用就越明显;3）"收益共享成本共担"式契约能够消除公平关切的负作用,达到航运供应链纵向联盟的最优收益和整体效率。     

Integrating regional and functional plans at Henkel

The article describes the planning system of the Henkel KGaA. The company is completely family owned. It is the fourth largest chemical company in Germany with affiliated companies nearly all over the world. The product range consists of consumer good articles such as detergents, cosmetics, household cleaners and adhesives and a wide range of chemical specialities which are sold to industry. The turnover world-wide is nearly DM7bn. The planning system of the Henkel KGaA is constructed in such a way that despite the necessity of short-term control the longer-term perspective still remains the basis for decision making. The planning structure and process throughout the company are explained in detail. The authors show that this system is an investment in managerial information processing.     

Risk analysis of estimates for cost of quality in supply chain: a case study

Risk analysis for Cost of Quality (CoQ) in supply chain has not been adequately researched as evidenced in the literature. This paper attempts to analyse risk involved in estimating elements of CoQ in the internal supply chain of an integrated aluminium manufacturing company. We have applied grounded theory methodology on accounting codes of the case company primarily to bring out various elements of CoQ in its internal supply chain. They are categorized as ‘cost of prevention’, ‘cost of defective inputs’, ‘cost of defect in process’, and ‘cost of defect in output’. These elements are considered to be risky due to availability of partial information in past records of accounts while applying grounded theory methodology. In order to estimate the range and probabilities of all possible outcomes of various categories CoQ in the supply chain, Monte Carlo simulation has been used. The results have facilitated decision makers in strategic total quality management.     

Planning and Scheduling in Supply Chains: An Overview of Issues in Practice

This paper gives an overview of the theory and practice of planning and scheduling in supply chains. It first gives an overview of the various planning and scheduling models that have been studied in the literature, including lot sizing models and machine scheduling models. It subsequently categorizes the various industrial sectors in which planning and scheduling in the supply chains are important; these industries include continuous manufacturing as well as discrete manufacturing. We then describe how planning and scheduling models can be used in the design and the development of decision support systems for planning and scheduling in supply chains and discuss in detail the implementation of such a system at the Carlsberg A/S beerbrewer in Denmark. We conclude with a discussion on the current trends in the design and the implementation of planning and scheduling systems in practice.     

Ford of Britain: A diminishing role in ford of Europe

In this paper, Michael McDermott highlights Ford of Britain and its changing role in Ford of Europe's operations. A review of the literature on foreign direct investment provides a framework for evaluating Ford Motor Company's current position and future strategy in Europe. This suggests that the company is in decline and in particular, that Ford of Britain has reached a stage where foreign divestment is likely: the Iberian peninsula is emerging as an attractive strategic alternative.The author concludes that, while the UK is losing its strategic importance as a market and a production base for Ford of Europe, any key decision to divest by the parent company is likely to involve lengthy analysis and therefore give time for public policy-makers to consider possible safeguards.     

Design of a strategic planning management information system

Information systems that are to support strategic planning must be developed on bases that reflect the unique nature of strategic organizational decisions. This paper presents a systems design methodology which implements five basic criteria for the design of a strategic planning Management Information System (MIS). The methodology uses discriminant analyses of the perceived importance to managers of various categories of strategic information to delineate the most significant information requirements of various managerial groups. These results are augmented with similar analyses based on the personal characteristics of the potential system users in order to implement a design criterion related to the integrated nature of a planning MIS and a ‘teaching’ objective which is posited to be valid and feasible for such a system.     

Decision support systems for production scheduling tasks- Part I of a case study: Analysis and task redesign

The first three steps of a new design method for decision support systems in production scheduling tasks are applied to a large bulk terminal. The operational characteristics of the company largely correspond with those of typical semiprocess industries. The design model used consists of five steps: production analysis, task analysis, task redesign, decision support design and decision support implementation. The results of the application of the design model up to the task redesign step are described.     

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.     

Two ways to handle dependent uncertainties in multi-criteria decision problems

We consider multi-criteria group decision-making problems, where the decision makers (DMs) want to identify their most preferred alternative(s) based on uncertain or inaccurate criteria measurements. In many real-life problems the uncertainties may be dependent. In this paper, we focus on multicriteria decision-making (MCDM) problems where the criteria and their uncertainties are computed using a stochastic simulation model. The model is based on decision variables and stochastic parameters with given distributions. The simulation model determines for the criteria a joint probability distribution, which quantifies the uncertainties and their dependencies. We present and compare two methods for treating the uncertainty and dependency information within the SMAA-2 multi-criteria decision aid method. The first method applies directly the discrete sample generated by the simulation model. The second method is based on using a multivariate Gaussian distribution. We demonstrate the methods using a decision support model for a retailer operating in the deregulated European electricity market.     

Real-time operation selection in an FMS using simulation- a fuzzy approach

Production management and scheduling problems in flexible manufacturing systems (FMSs) are more complicated than those problems in job shops and transfer lines. Due to the flexibility of FMSs, alternative operation is common. When considering the operational problems of FMSs such as scheduling, simulation methodology seems to be useful to address these issues. Real-time scheduling schemes use simulation techniques     

Improving throughput for an electronic assembly line using a constraint analysis methodology

Electronic assembly operations are vital to industries such as telecommunications, computers and consumer electronics. This paper presents a constraint analysis methodology for planning and improving electronic assembly operations that draws on concepts from queueing theory, simulation and production planning. The proposed methodology identifies the operational bottleneck and predicts the utilization, throughput and lead time of the assembly line. It also quantifies the relationship between yields and utilization for the assembly operations. A case study is presented that applies the methodology at an Ericsson, Inc., telecommunications equipment assembly facility. The constraint analysis methodology provided valuable decision support as the managers of Ericsson evaluated the costs and benefits of additional production capacity. Although the focus of this paper is electronic assembly operations, the methodology can be applied to general flow line assembly systems with feedback loops for test and rework under dedicated high-volume production.