Showing papers in "International Journal of Production Research in 2008"

Global supplier selection: a fuzzy-AHP approach

Abstract: Global supplier selection has a critical effect on the competitiveness of the entire supply chain network. Research results indicate that the supplier selection process appears to be the most significant variable in deciding the success of the supply chain. It helps in achieving high quality products at lower cost with higher customer satisfaction. Apart from the common criteria such as cost and quality, this paper also discusses some of the important decision variables which can play a critical role in case of the international sourcing. The importance of the political-economic situation, geographical location, infrastructure, financial background, performance history, risk factors, etc., have also been pointed out in particularly in the case of global supplier selection. Supplier selection problem related to the global sourcing is more complex than the general domestic sourcing and as a result it needs more critical analysis, which could not be found properly in past available literatures. This paper di...

Performance measurement using overall equipment effectiveness (OEE): literature review and practical application discussion

Abstract: The quest for improving productivity in the current global competitive environment has led to a need for rigorously defined performance-measurement systems for manufacturing processes. In this paper, overall equipment effectiveness (OEE) is described as one such performance-measurement tool that measures different types of production losses and indicates areas of process improvement. Analysis is done on how OEE has evolved leading to other tools like total equipment effectiveness performance, production equipment effectiveness, overall factory effectiveness, overall plant effectiveness, and overall asset effectiveness. Two industrial examples of OEE application are discussed, and the differences between theory and practice analysed. Finally, a framework for classifying and measuring production losses for overall production effectiveness is proposed. The framework harmonizes the differences between theory and practice and makes possible the presentation of overall production/asset effectiveness that can be...

Reconfigurable manufacturing systems: the state of the art

Abstract: In this paper, general requirements of next generation manufacturing systems are discussed, and the strategies to meet these requirements are considered. The production paradigms which apply these strategies are also classified. Particular emphasis is put on the paradigm of Reconfigurable Manufacturing System (RMS). Some key issues of the RMS design are discussed, and a critical review is presented concerning the developments of RMSs. Finally, suggestions of the RMS research are made and future research directions are identified.

Modeling Industrial Lot Sizing Problems: A Review

Abstract: In this paper we give an overview of recent developments in the field of modeling deterministic single-level dynamic lot sizing problems. The focus of this paper is on the modeling of various industrial extensions and not on the solution approaches. The timeliness of such a review stems from the growing industry need to solve more realistic and comprehensive production planning problems. First, several different basic lot sizing problems are defined. Many extensions of these problems have been proposed and the research basically expands in two opposite directions. The first line of research focuses on modeling the operational aspects in more detail. The discussion is organized around five aspects: the set ups, the characteristics of the production process, the inventory, demand side and rolling horizon. The second direction is towards more tactical and strategic models in which the lot sizing problem is a core substructure, such as integrated production-distribution planning or supplier selection. Recent advances in both directions are discussed. Finally, we give some concluding remarks and point out interesting areas for future research.

Augmented reality applications in manufacturing: a survey

Abstract: Augmented reality (AR) is a novel human–machine interaction that overlays virtual computer-generated information on a real world environment. It has found good potential applications in many fields, such as military training, surgery, entertainment, maintenance, assembly, product design and other manufacturing operations in the last ten years. This paper provides a comprehensive survey of developed and demonstrated AR applications in manufacturing activities. The intention of this survey is to provide researchers, students, and engineers, who use or plan to use AR as a tool in manufacturing research, a useful insight on the state-of-the-art AR applications and developments.

In pursuit of implementation patterns: the context of Lean and Six Sigma

Abstract: Combining Lean practices with Six Sigma has gained immense popularity in recent years. Whether a combined Lean-Six Sigma approach is the latest management fad, or leads to significant performance benefits that exceed isolated implementation is not yet apparent. Using implementation and performance data from a sample of 2511 plants, the research study attempts to uncover associative and predictive pattern of implementation between 15 Lean practices and the Six Sigma program. Our results indicate two major findings. First, implementation of any practice from a broader set of Lean practices improves the likelihood of implementing Six Sigma. Additionally, practices commonly bundled under quality management predict and distinguish the group of plants implementing Six Sigma extensively from non-implementers. Second, the regression results indicate a significant difference in the performance levels of the Six Sigma implementers group compared with the non-implementer group. These preliminary results are a first ...

Characteristics of the research on reverse logistics (1995–2005)

Abstract: This paper aims to describe and analyse the main characteristics of articles on reverse logistics published in the production and operations management field, in order to determine the evolution of this current research over recent years and improve our understanding of this issue. We built up a database with the articles on reverse logistics published in the most relevant journals within the period 1995–2005, and we have explored the topic, the methodology and the techniques of analysis, as well as other relevant aspects of the research. We have evaluated the first decade of research on reverse logistics, observing what has been done and how, where and by whom it has been carried out. The result is an extensive review of the research works that have created and developed the reverse logistics concept, outlining some directions of research for the near future and offering practical help to those who begin to research on this topic.

An ISM approach for modelling the enablers of flexible manufacturing system: the case for India

Abstract: The volatile condition of today's market is forcing the manufacturing managers to adapt the flexible manufacturing systems (FMS) to meet the challenges imposed by international competition, ever changing customer demands, rapid delivery to market and advancement in technology. There are certain enablers, which help in the implementation of FMS or in the transition process from traditional manufacturing systems to FMS. The utmost need is to analyse the behaviour of these enablers for their effective utilization in the implementation of FMS. The main objective of this paper is to understand the mutual interaction of these enablers and identify the ‘driving enablers’ (i.e. which influence the other enablers) and the ‘dependent enablers’ (i.e. which are influenced by others). In the present work, these enablers have been identified through the literature, their ranking is done by a questionnaire-based survey and interpretive structural modelling (ISM) approach has been utilized in analysing their mutual inter...

A leanness measure of manufacturing systems for quantifying impacts of lean initiatives

Abstract: Various lean tools and techniques have been developed for process improvement. In order to track the progress, lean metrics were developed correspondingly. However, an integrated and quantitative measure of overall leanness level has not been established. This paper proposes a unit-invariant leanness measure with a self-contained benchmark to quantify the leanness level of manufacturing systems. Evolved from the concept of data envelopment analysis (DEA), the leanness measure extracts the value-adding investments from a production process to determine the leanness frontier as a benchmark. A linear program based on slacks-based measure (SBM) derives the leanness score that indicates how lean the system is and how much waste exists. Using the score, impacts of various lean initiatives can be quantified as decision support information complementing the existing lean metrics.

Profit-oriented disassembly-line balancing

Abstract: As product and material recovery has gained importance, disassembly volumes have increased, justifying construction of disassembly lines similar to assembly lines. Recent research on disassembly lines has focused on complete disassembly. Unlike assembly, the current industry practice involves partial disassembly with profit-maximization or cost-minimization objectives. Another difference between assembly and disassembly is that disassembly involves additional precedence relations among tasks due to processing alternatives or physical restrictions. In this study, we define and solve the profit-oriented partial disassembly-line balancing problem. We first characterize different types of precedence relations in disassembly and propose a new representation scheme that encompasses all these types. We then develop the first mixed integer programming formulation for the partial disassembly-line balancing problem, which simultaneously determines (1) the parts whose demand is to be fulfilled to generate revenue, (...

A collaborative ant colony algorithm to stochastic mixed-model U-shaped disassembly line balancing and sequencing problem

Abstract: Disassembly operations are inevitable elements of product recovery with the disassembly line as the best choice to carry out the same. In the light of different structures of returned products (models) and variations in task completion times, the process of disassembly could not be efficiently mapped on a simple straight line. Another important issue that needs consideration is the task-time variability pertaining to human factor. In order to resolve these complexities a Mixed-Model U-shaped Disassembly Line with Stochastic Task Times has been proposed in this article. A novel approach, Collaborative Ant Colony Optimization (CACO), has been utilized that simultaneously tackles the interrelated problem of line balancing and model sequencing. The distinguishing feature of the proposed approach is that it maintains bilateral colonies of ants which independently identifies the two sequences, but utilizes the information obtained by their collaboration to guide the future path. The approach is tested on benchm...

Relationship building, lean strategy and firm performance: an exploratory study in the automotive supplier industry

Abstract: In contrast to previous literature, we propose that commitment to lean strategy should be preceded by building close relationships with key supply chain partners (suppliers and customers). Two aspects of lean strategy, lean manufacturing and lean design are studied in this paper. We hypothesize that relationship building positively affects both aspects of lean strategy, which in turn positively influences firm performance. To test these relationships, we use data from the top 150 auto suppliers to the ‘Big Three’ original equipment manufacturers (OEMs). The results show positive relationships between (1) relationship building and lean design, (2) relationship building and lean manufacturing, and (3) lean design and firm performance. This suggests that relationship building is more valuable for enhancing the ‘product’ aspects of lean strategy as opposed to the ‘process’ aspects of lean strategy. Process aspects of lean strategy appear to be largely a function of internal efforts.

Multi-agent systems applications in manufacturing systems and supply chain management: a review paper

Abstract: This paper offers a review of the development and use of multi-agent modelling techniques and simulations in the context of manufacturing systems and supply chain management (SCM). The objective of the paper is twofold. First, it presents a comprehensive literature review of current multi-agent systems (MAS) research applications in the field of manufacturing systems and SCM. Second, it aims to identify and evaluate some key issues involved in using MAS methods to model and simulate manufacturing systems. A variety of different MAS applications are reviewed in three different classified research areas: production design and development, production planning and control, and SCM. In presenting a detailed taxonomy of MAS applications, the paper describes MAS application domains from five different perspectives. The review suggests the MAS approach represents a feasible framework for designing and analysing real-time manufacturing operations, since the approach is capable of modelling different levels of agen...

Using a multiple-GA method to solve the batch picking problem: considering travel distance and order due time

Abstract: Warehousing involves all activities related to the movement of goods such as receiving, storage, order picking, accumulation, sorting and shipping within warehouses or distribution centres. Among these activities, order picking is the most costly process because its operations are labour-intensive and repetitive. In this paper, we propose a batch picking model that considers not only travel cost but also an earliness and tardiness penalty to fulfil the current complex and quick-response oriented environment. This model is solved using a multiple-GA method for generating optimal batch picking plans. The core of the multiple-GA method consists of the GA_BATCH and GA_TSP algorithms. The GA_BATCH algorithm finds the optimal batch picking plan by minimizing the sum of the travel cost and earliness and tardiness penalty. The GA_TSP algorithm searches for the most effective travel path for a batch by minimizing the travel distance. To exhibit the benefits of the proposed model a set of simulations and a sensitiv...

A multi-objective model for project portfolio selection to implement lean and Six Sigma concepts

Abstract: Lean and Six Sigma methodologies play an important role in the quality and cost driven world with high competition. In this paper, we develop a unique decision support system that utilizes a multi-objective formulation for project portfolio selection problem in manufacturing companies. The model can be used to effectively implement Lean and Six Sigma concepts. An industrial case study that utilizes this model for implementing the Lean and Six Sigma initiatives is also presented.

Evaluation of value stream mapping in manufacturing system redesign

Abstract: The value stream mapping (VSM) technique, developed within the lean production paradigm, was presented as an innovative graphic technique to help practitioners redesign production systems. This paper presents the results of a project whose main purpose is to evaluate the real applicability of VSM to redesign disconnected flow lines based on manufacturing environments with a diversity of logistical problems. The research was developed using multiple case study methodology in six industrial companies. The experiences have served to highlight the following results: (1) the validity of VSM as a redesign tool is confirmed; (2) resources required for the application process are established; and (3) the differences between theoretical concepts proposed by VSM and their real-world practical applications are indicated and analyzed. These results have led to conclusions relating to: (1) communication solutions for practitioners to obtain maximum efficiency when using VSM; and (2) definitions of theoretical developm...

Optimal Storage Rack Design for a 3-dimensional Compact AS/RS

Abstract: In this paper, we consider a newly designed compact three-dimensional automated storage and retrieval system (AS/RS). The system consists of an automated crane taking care of the pallets' movements in the horizontal and vertical direction. A gravity or powered conveying mechanism takes care of the pallets' depth movement in the rack. Our research objective is to analyze the system performance and optimally dimension the system. For single-command cycles, the crane's expected retrieval travel time is the same for gravity and powered conveyors; we give a closed-form expression. From the expected travel time, we calculate the optimal ratio between three dimensions that minimizes the travel time for a random storage strategy. In addition, we derive an approximate travel time expression for dual command cycles for the system with powered and gravity conveyors, respectively, and use it to optimize the system dimensions. Finally, we illustrate the findings of the study by a practical example.

Augmented reality for assembly guidance using a virtual interactive tool

Abstract: The application of augmented reality (AR) technology for assembly guidance is a novel approach in the traditional manufacturing domain. In this paper, we propose an AR approach for assembly guidance using a virtual interactive tool that is intuitive and easy to use. The virtual interactive tool, termed the virtual interaction panel (VirIP), is an easy-to-use tool that can be used to interactively control AR systems. The VirIP is composed of virtual buttons, which have meaningful assembly information that can be activated by an interaction pen during the assembly process. The interaction pen can be any general pen-like object with a certain colour distribution. It is tracked using a restricted coulomb energy (RCE) network in real-time and used to trigger the relevant buttons in the VirIPs for assembly guidance. Meanwhile, a visual assembly tree structure (VATS) is used for information management and assembly instructions retrieval in this AR environment. VATS is a hierarchical tree structure that can be ea...

On reference models for collaborative networked organizations

Abstract: A growing number of collaborative networked organizations can be found in industry, services, and research. However, the lack of a reference model that could synthesize and formalize the base concepts, principles, and recommended practices, is an obstacle for an easier and more consistent development of the area. Therefore, after a clarification of concepts and terminology, the ARCON reference modeling approach is proposed considering multiple modeling perspectives: environment characteristics, life cycle, and modeling intent. This novel modeling framework takes into account contributions from previous works on enterprise modeling and extends them to the context of collaborative networked organizations. A taxonomy of collaborative networks is introduced. Examples of concepts to be part of a reference model are collected and abstracted from several manifestations of collaborative networks. Establishing a reference model in this area is a long-term endeavor; therefore this contribution is aimed as just a st...

Finding Collaborative Innovation Networks Through Correlating Performance with Social Network Structure

Abstract: This paper contributes to the ongoing stream of research correlating social network structure with individual and organizational performance. While teaching a course on optimizing online communication behaviour and social network analysis, we collected preliminary data on the relationship between dynamic social network structures and individual and team performance. Students from Helsinki University of Technology and University of Cologne, who had never met face to face, formed virtual interdisciplinary teams collaborating on a common task, the communication analysis of online communities. As part of their task, students correlated performance of the community they were analysing with social network structure. In this research, we compare social network structure and individual and team performance of participants in a multi-user online computer game with social network structure and performance among the student teams. While among computer gamers the number of communication links predicts performance, a ...

Framework for flexibility in dynamic supply chain management

Abstract: Effective Supply Chain Management (SCM) is a pivotal issue in the dynamically changing business environment. Dynamic SCM requires integrated decision-making amongst autonomous chain partners with effective decision information synchronization amongst them. By exploiting flexibility in supply chain structures, better performance can be achieved. Similarly, by judiciously employing decision flexibility and the associated dynamic control amongst autonomous supply chain nodes, many improvements are possible. The paper presents a study on the role of different flexibility options (i.e. no flexibility, partial flexibility and full flexibility) in a dynamic supply chain model based on some key parameters and performance measures. Supply chain flexibility has significant potential and needs a greater research attention. The paper attempts to advance the knowledge of dynamic control on effective flexibility exploitation in the context of dynamic supply chains. A simulation model of a dynamic supply chain is used f...

An empirical investigation of supply chain strategy typologies and relationships to performance

Abstract: We propose a typology of supply chain management strategies based on data from a large sample of US firms. The resulting typologies and their relationships with firm performance are tested. The result of set correlation analysis on the data revealed six distinct supply chain management typologies, and showed significant statistical relationships with performance. Additional analysis revealed that two of the typologies describe the ideas of velocity, variability, and visibility of supply chains. The paper also discusses the relationship between product life cycle and the supply chain management initiatives that comprise the strategy typologies.

U-shaped assembly line balancing problem with genetic algorithm

Abstract: This paper presents a multi-objective genetic algorithm (moGA) to solve the U-shaped assembly line balancing problem (UALBP). As a consequence of introducing the just-in-time (JIT) production principle, it has been recognized that U-shaped assembly line systems offer several benefits over the traditional straight line systems. We consider both the traditional straight line system and the U-shaped assembly line system, thus as an unbiased examination of line efficiency. The performance criteria considered are the number of workstations (the line efficiency) and the variation of workload. The results of experiments show that the proposed model produced as good or even better line efficiency of workstation integration and improved the variation of workload.

Order batching in walk-and-pick order picking systems

Abstract: This paper investigates the order-batching problem both as a theoretical problem, including its special variants, and as a practical problem, with possible heuristic solution procedures. It shows that certain special cases or variants of the order batching problem are solvable, while other cases of the problem are NP-hard. It also develops a new Mixed-Integer Programming (MIP) model to obtain near-exact solutions to the problem. The MIP provides good lower and upper bounds to the problem, which prove useful in the investigation of the heuristic solution procedures. The paper identifies and modifies slightly the order batching heuristic, which shows the strongest results in the numerical experiments. Although good solutions are obtained with this particular heuristic, the results indicate that it is computationally intensive. Furthermore, solutions obtained through the MIP model suggest there is still room to obtain even better solutions to the problem via heuristic procedures, although the challenge is to...

Application support to product variety management

Abstract: Offering a large variety of products at competitive prices and reasonable delivery times is a complex managerial challenge that many companies have to address. Software vendors responded to this challenge by developing and proposing various solutions, such as product configuration (PC) systems, product data management (PDM) systems and customer relationship management (CRM) systems. The relative newness, complexity and mutual interdependencies among these systems make it difficult to understand how they—individually and as a whole—actually support a firm in managing its product variety. Precisely these complexities, ultimately, add to the risks of software selection, leading companies to make inconsistent choices or to implement the wrong systems. Starting from this theoretical and practical concern, the present paper provides a conceptualization of the essential functions of PC, PDM and CRM systems, discussing how these functions help a company to manage its product variety and how they relate to each ot...

A framework for defining both qualitative and quantitative supplier selection criteria considering the buyer–supplier integration strategies

Abstract: Previous research has reported that the decision criteria used to evaluate suppliers differ by product category This paper presents a framework for defining the supplier selection criteria by investigating possible quantitative and qualitative criteria reported by earlier studies according to the levels of buyer–supplier relationship, the company's competitive situation and its corporate strategies, rather than investigating these criteria in respect of product category The solution proposed in this study not only assists decision makers to define selection criteria, but also supports determining the buyer–supplier integration level An actual case in Audio Electronics, a Turkish electronics business, demonstrates the feasibility of applying the proposed framework in practice

A particle swarm optimization algorithm for hybrid flow-shop scheduling with multiprocessor tasks

Abstract: The multistage hybrid flow-shop scheduling problem with multiprocessor tasks has been found in many practical situations. Due to the essential complexity of the problem, many researchers started to apply metaheuristics to solve the problem. In this paper, we address the problem by using particle swarm optimization (PSO), a novel metaheuristic inspired by the flocking behaviour of birds. The proposed PSO algorithm has several features, such as a new encoding scheme, an implementation of the best velocity equation and neighbourhood topology among several different variants, and an effective incorporation of local search. To verify the PSO algorithm, computational experiments are conducted to make a comparison with two existing genetic algorithms (GAs) and an ant colony system (ACS) algorithm based on the same benchmark problems. The results show that the proposed PSO algorithm outperforms all the existing algorithms for the considered problem.

Human resources in advanced environmental approaches - a case analysis

Abstract: A weak organizational culture creates an environment that leads to inefficiencies in human resources. Both a weak organizational culture and inefficiencies in human resources are major barriers to the implementation of environmental action processes. However, very few studies have been published in this area. The objective of this study, therefore, is to conduct an exploratory case analysis and develop some proposals based on the conclusions arrived at. We have analyzed a total of 8 factories to ensure a sufficient number of sources of information. Some factors linked to organizational culture and the human resource management in a factory that favour environmental performance were found.

A simple metaheuristic approach to the simultaneous scheduling of machines and automated guided vehicles

Abstract: In this paper we address the problem of simultaneous scheduling of machines and vehicles in flexible manufacturing systems. The studied problem is a job shop where the jobs have to be transported between the machines by automatic guided vehicles. In addition to the processing of jobs, we consider the transportation aspect as an integral part of the optimization process. To deal with this problem, we propose a new solution representation based on vehicles rather than machines. Each solution can thus be evaluated using a discrete event approach. An efficient neighbouring system is then described and implemented into three different metaheuristics: iterated local search, simulated annealing and their hybridisation. Computational results are presented for a benchmark of 40 literature instances. New upper bounds are found for 11 of them, showing the effectiveness of the presented approach.

An efficient cycle time model for autonomous vehicle storage and retrieval systems

Abstract: A computationally efficient cycle time model for conceptualizing autonomous vehicle storage and retrieval systems and comparing their performance with crane-based automated storage and retrieval systems is presented. The model is based on an iterative computational scheme exploiting random storage assumptions and queuing model approximations. Relative to earlier models, the procedure scales up efficiently for large problems thereby enabling more extensive search of a design solution space. Simulation based validation studies suggest that model accuracy is adequate for system conceptualization. The procedure is demonstrated using realistically sized sample problems.