Subhash Wadhwa

A heuristic methodology for order distribution in a demand driven collaborative supply chain

This paper studies vertical and horizontal supply chain collaboration, and proposes a demand sharing methodology based on a set of predefined collaboration rules. Supply chain collaboration is prevalent, and has been recognized to be one of the important issues in improving competition strength. However, implementation of supply chain collaboration encounters many barriers, such as type, scope and security of information sharing, equity in benefits sharing, joint decision making, coordination tasks etc. For these reasons this paper proposes a framework of a central coordination system, which is equipped with a multi-criteria genetic optimization feature. The optimization methodology combines an analytic hierarchy process with genetic algorithms. It deploys an analytic hierarchy process to model the collaboration rules, govern the demand allocations, and evaluate the fitness values of chromosomes. The implementation of the proposed central coordination system is demonstrated by a hypothetical three-echelons supply chain network.

Evaluating petroleum supply chain performance

Purpose – Performance evaluation in supply chain management (SCM) is not a straightforward task. This becomes even more complicated while evaluating a process industry supply chain because of its inherently different characteristics. The purpose of this paper is to suggest a method to evaluate the performance of one such process supply chain, namely the petroleum industry supply chain.Design/methodology/approach – The paper uses a combination of analytical hierarchy process (AHP) and balanced scorecard (BSC) for evaluating performance of the petroleum supply chain. The choice of factors determining supply chain performance under the four perspectives of BSC has been validated using opinion from subject matter experts (SMEs). In order to determine relative importance of criteria opinion of SMEs has been collected in the form of pairwise comparisons. Using these comparisons, the AHP technique has been applied to determine the relative weights of various perspectives as well as the factors under each perspec...

Implementing supply chain management in a firm: issues and remedies

Purpose – When a supply chain initiative is taken up by a firm a number of issues come up during implementation. The purpose of this paper is to identify some of the major issues related to such implementation and draw out practices from literature to serve as remedies for these issues.Design/methodology/approach – The paper starts by suggesting a broad framework for implementing supply chain management (SCM) in a firm. This consists of strategy formulation, identification of areas for improving material flow, identifying issues in these areas, and finally performance evaluation in order to determine how well the supply chain initiative has been implemented. Subsequently, the paper follows this framework step by step and in the process identifies the issues likely to arise in the process of SCM implementation. By reviewing current literature it suggests how these issues can be handled effectively.Findings – The major issues related to SCM implementation are in the areas of logistics, outsourcing/partnersh...

Impact of Routing Flexibility on the Performance of an FMS—A Simulation Study

The evolving manufacturing environment is characterized by a drive toward increasing flexibility. One possible manifestation of flexibility within an FMS is in the form of routing flexibility. Providing this typically is an expensive proposition, and system designers therefore aim to provide only the required levels commensurate with a given set of operating conditions. This paper presents a framework based on a Taguchi experimental design for studying the nature of the impact of varying levels of routing flexibility on the performance of an FMS. Simulation results indicate that increases in routing flexibility, when made available at the cost of an associated penalty on operation processing time, is not always beneficial. There is an optimal flexibility level, beyond which system performance deteriorates, as judged by the makespan measure of performance. It is suggested that the proposed methodology can be used in practice for not only setting priorities on specific design and control factors but also for highlighting likely factor level combinations that could yield near-optimal shop performance.

Comparative performance analysis of a flexible manufacturing system (FMS): a review-period-based control

The flexibility of a flexible manufacturing system (FMS) has provided it with the capability to become one of the most suitable manufacturing systems in the present manufacturing environment of customized and an increasing variety of products with shorter life cycles. Significant research has been made on flexibility from different points of views. The paper focuses on the study of flexibility in FMS from the view of a decision-and-information system. In modelling flexibility and other physical and operational parameters of an FMS, researchers have mostly assumed a decision-and-information system has the capability of real-time control. The literature reports qualitatively that real-time control may be difficult to achieve and justify economically. The paper presents a comparative study of an FMS operating under real-time control, review-period-based control and reactive control. It also focuses on the comparative performances of the key parameters such as routing flexibility and control strategies of an FMS operating under these different modes of a decision-and-information system. It contributes an approach using simulation under Taguchis method to study the various factors contributing to FMS performance and identifies the critical parameters for improving performance. The result shows that review-period-based control can be effectively implemented in an FMS with a lower flexibility level. Smaller review-period size can perform comparable with real-time control. The decision-maker must ensure the FMSs capability of having real-time control, otherwise it may result in a reactive control that may considerably deteriorate the performance. The results under Taguchis method indicate that the routing flexibility and control strategy should have maximum relative percentage contributions in the performance of an FMS, while the decision-and-information system should have the minimum. Increasing the relative percentage contribution of a decision-and-information system may deteriorate the performance of a given FMS.

Organizing a virtual manufacturing enterprise: an analytic network process based approach for enterprise flexibility

Virtual manufacturing is a dynamic enterprise structure that will enable future competitiveness in the fast changing business environment. This is made possible through quick IT based integration of flexible and core competent business entities capable of providing value-added product and services. Flexibility elements represent change capabilities of enterprise wide processes and resources in time and cost dimensions. Value chain considerations require synergy among the participating flexible resources. Also decision information synchronization delays need to be managed so that other entity flow processes in the enterprise remain well synchronized. This may require a capability of dynamic changes in flexible structures leading to effective virtual enterprises. There is a need to develop suitable enterprise architectures for virtual enterprises that offer an increasing focus on agility. Infrastructure support for integration of flexible capability to attain synergy among resources is necessary for enterprise agility. We conceptualize virtual manufacturing (VM) as an integrating infrastructure of flexible resources made possible through alliance of enterprises that are individually core competent in specific business function. Such a VM can attain the required cost, flexibility and responsiveness characteristics in its operations to provide solution to the demanding customer in a global dynamic market. Modelling frameworks depicting these composite flexibility states have complex and tacit interrelationship with plural business goals. Analytical network process (ANP) has been used to model the interrelationship of different decision domains with a view to prioritize enterprise wide flexibility dimensions. The ANP modelling framework takes into consideration the interdependency among sub-strategies. We demonstrate through sensitivity analysis that strategic shift is required to accommodate changes due to dynamic condition in the business environment.

Quality award dimensions: a strategic instrument for measuring health service quality

Purpose – The purpose of this paper is to describe research which compared quality awards and the selection of criteria for assessing health care processes quality status, in private sector health care institutions in India.Design/methodology/approach – A comparison of quality awards was performed and criteria were selected for assessing health care processes quality status. The relationships in the model, as measured by the instrument, was the works main objective. Using the Malcolm Baldrige National Quality Award, European Foundation for Quality Management and Kanji Business Excellence Model, common factors were extracted to measure the quality perceptions of health care organizations and to measure the relationships among the quality dimensions. The sample selected for this study comprised healthcare stakeholders.Findings – As a result of respondents knowledge, data provide unique insights into the relationships among the dimensions that compose quality in healthcare organizations. Principal componen...

Increase in flexibility: productive or counterproductive? A study on the physical and operating characteristics of a flexible manufacturing system

In time-based performances of a manufacturing system, flexibility has played a pivotal role. Significant research efforts have been made from defining the various types of flexibility in flexible manufacturing systems (FMS) to the performance measurement index of flexibility levels. This paper focuses on the physical and operating characteristics of alternative machines (available by the virtue of flexibility), which may not have been explicitly modelled with flexibility. The decision-maker needs to know how physical and operating characteristics such as processing time, machine setting time, tool changing time, transportation time, control strategies enforced, etc. may influence the changed level of flexibility in an FMS. Does an increase in flexibility have the expected benefits or not? If benefits are present, then up to what level of flexibility? Answers to these questions will provide an insight to the decision-maker to decide a gainful level of flexibility for a given physical and operating characteristics of an FMS. This paper contributes an approach to identify productive and counterproductive performance zones of an FMS at different flexibility levels while considering physical and operating characteristics. It also demonstrates the need of modelling explicitly the physical and operating characteristics of a system with flexibility, and it presents a simulation study of these parameters for a given FMS. The results show that expected gains from an increasing level of flexibility may not be present while considering physical and operating characteristics. Flexibility can be increased strategically up to a certain level with benefits when considering the physical and operating characteristic of the system. A further increase in flexibility level may be counterproductive.

Fuzzy systems for control of flexible machines operating under information delays

The performance of a manufacturing system with a defined level of flexibility is determined by the effectiveness of the control strategy employed. The success of the latter is critically dependent upon information intensive activities including information collection, transfer and processing. Each of these activities consumes time and thus causes delays. We refer to these delays as information delays. Most real-world manufacturing systems operate under conditions that entail significant information delays. Thus, there is a need to model, analyse and evolve control strategies that can perform well under such delays. This paper focuses on the design of a suitable control strategy for a simple system operating in a stochastic environment with information delays. System stochasticity coupled with information delay has a compounding effect on the uncertainty of the environment within which decisions must be taken thus providing motivation to explore the development of control strategies based on fuzzy logic. W...

Taguchi's Method Analysis of an FMS Under Review-Period-Based Operational Controls: Identification of Control Periodicity

Flexibility of flexible manufacturing systems (FMSs) has been considered as an effective tool to compete in the present manufacturing environment. Enormous research efforts have been made to harness the benefits of flexibility through superior control strategies. While modeling flexibility and control strategies, researchers have mostly assumed an information system that can provide real-time control. Literature qualitatively reports that the real-time control can be highly capital intensive and difficult to achieve. This paper focuses on FMS operating under review-period (RP)-based control and presents a combined study of routing flexibility (RF), control strategies, and information system under Taguchis method using simulation. RP-based control for FMS has been compared with real-time control. This paper contributes an approach for the decision maker to study the performance of an FMS operating under RP control and to identify the periodicity (time interval) of RP that will not deteriorate its performance in comparison to real-time control. It also helps the decision maker to reach a tradeoff between RP-based control and real-time control. The results show that RP-based control can be effectively implemented on an FMS having lower RF level. RP-based control can outperform real-time control with a superior control strategy and smaller RP size. The results under Taguchis method suggest that the RF and control strategy should have maximum relative percentage contributions in FMS performance, whereas contribution of the RP (information system) should be minimum. Increasing the relative percentage contribution of the information system may deteriorate the performance of FMS. The information system is needed as a catalyst to facilitate the contributions of other factors in improving the FMS performance and not its own contribution