Chuda Basnet

Inventory lot-sizing with supplier selection

This paper presents a multi-period inventory lot-sizing scenario, where there are multiple products and multiple suppliers. We consider a situation where the demand of multiple discrete products is known over a planning horizon. Each of these products can be sourced from a set of approved suppliers, a supplier-dependent transaction cost applying for each period in which an order is placed on a supplier. A product-dependent holding cost per period applies for each product in the inventory that is carried across a period in the planning horizon. The decision maker needs to decide what products to order in what quantities with which suppliers in which periods. An enumerative search algorithm and a heuristic are presented to address the problem.

Scheduling and control of flexible manufacturing systems: a critical review

Abstract Flexible manufacturing systems (FMS) are distinguished by the use of computer control in place of the hard automation usually found in transfer lines. The high investment required for an FMS and the potential of FMS as a strategic competitive tool make it attractive to engage in research in this area. This paper presents a review of literature concerning the operations aspect of FMS. Articles emphasizing many methodological perspectives are critically reviewed. The review is carried out from multiple viewpoints. Future research directions are suggested.

Benchmarking Supply Chain Management Practice in New Zealand

This paper reports on a benchmarking study carried out on supply chain management (SCM) activities of manufacturing organisations in New Zealand. The purpose of the paper is to report the current state of the play in this area. A postal survey was carried out to ascertain the status of SCM adoption in New Zealand, and identify the issues in SCM that are significant for New Zealand manufacturers. The findings suggest that although there is awareness of the SCM concept in New Zealand, the adoption of the newer concepts of SCM is not very far advanced.

FleetManager: a microcomputer-based decision support system for vehicle routing

Abstract We report on a decision support system (DSS) that recommends solutions to a particular version of the vehicle routing problem occurring in the New Zealand dairy industry. FleetManager is a DSS developed for use by New Zealand milk tanker schedulers and is designed to aid them in creating or improving milk tanker routes using their experience and preferences. The DSS uses multiple, resizable, overlapping windows to assist schedulers in their tasks. Users can also interact with the system through a graphical interface which displays a road map of the area and the location of the milk processing plants and milk suppliers. FleetManager also contains the option of automatically creating vehicle routes, which can be modified by the users. The system can be used to analyze a wide variety of “What-if?” scenarios with potential cost impacts.

Scheduling contractors' farm-to-farm crop harvesting operations

The harvesting of renewable resources from an operations scheduling viewpoint is introduced, and a harvesting scenario arising in the agricultural context involving a commercial contracting enterprise that travels from farm-to-farm harvesting crops is discussed. This paper is an extension of previous work by two of the authors from the one-farm to the multi-farm case. In both cases, the duration of each operation is dependent upon the combination of constrained resources allocated to it, equipment and worker allocation is restricted, and minimum or maximum time lags on the start and completion of operations may be imposed. The present case incorporates harvesting at more than one farm and thus the sequence in which the farms are visited and the inter-farm travel times must be taken into account. We report on a harvesting scheduling model and solution procedures designed specifically for large-scale versions of the multi-farm case. The computational times experienced in solving general instances of the model of small-to-medium practical size by a commercial integer programming package are encouraging. Greedy and tabu search heuristics, which are capable of solving problems of relatively large dimensions in reasonable computational time are also included. The authors believe that the model and the solution techniques developed represent a useful addition to the farm crop contractors tool kit.

Optimal maintenance scheduling for water distribution systems

Abstract The scheduling of maintenance for water distribution systems is a complex task encompassing a wide range of alternatives. The methodology presented in this paper can consider the major piping alternatives of replacing and cleaning, and relining. It also considers the potential of pumping improvements while accounting for the costs of maintenance, failure and operations for a multiple-period planning horizon. To solve the problem a nonlinear optimization model is linked with a network simulation model. The application showed that the procedure can determine solutions in reasonable times.

The impact and benefits of a DSS: the case of FleetManager

Abstract A DSS used for vehicle routing at the Westland Co-operative Dairy Company Ltd., New Zealand, is providing a spectrum of benefits and business values. Labor hours, required by the schedulers, have been significantly reduced; the schedules they develop are more efficient, the number of truck drivers has been reduced even though the volume of the traffic is increasing, and the Transport Office has a greater flexibility and higher morale. The system includes powerful tools to plan schedules, choose plans, generate alternative plans, and assess alternative plans with respect to the given criteria. The system also allows the scheduler to create routes automatically, minimize the total distance traveled, and manually modify routes created by a model. It also has several classic characteristics that are too seldom actually realized: it leverages the judgment of the DSS user; it has evolved over time through an iterative development process and is being adapted for use in another company. Taken together, these benefits and attributes make the system a rare example of a successful DSS that can provide guidance for the development of other systems in the important problem domain of vehicle routing.

The measurement of internal supply chain integration

Purpose - Internal supply chain refers to the chain of activities within a company that concludes with providing a product to the customer. This process involves multiple functions within companies such as sales, production, and distribution. It is obvious that a companys performance would be enhanced by the integration of these functions. However, there is no consensus yet on how integration is to be defined and measured. The purpose of this paper is to present research that was conducted with the goal of developing an instrument for the measurement of internal supply chain integration. Design/methodology/approach - Scale items were identified from current literature and the resulting survey instrument was sent out to a sample of New Zealand manufacturers. Statistical analysis was conducted to purify and validate the instrument. Findings - In total, three dimensions of integration were identified, labelled coordination, communication, and affective relationship. This paper makes a contribution towards developing a consensus in the understanding and measurement of the integration construct. Research limitations/implications - The selection and exclusion of measurement items for the survey have followed established principles of survey research, but may have been affected by the personal bias of the author. While every attempt has been made to comprehensively capture the state of the research up to the time of the study, there may be some omissions. The sample for the survey was drawn from a database of New Zealand businesses, thus the results are generalizable only to the extent that these businesses represent the population of all businesses. Another limitation is that no prior survey/case studies were carried out to collect practitioners definitions/measures for integration. Practical implications - The authors hope to have made a contribution here towards building a consensus among practitioners and researchers in defining and measuring internal supply chain integration. For practitioners, the measurement instrument offers a self-assessment tool for internal supply chain integration. This should help them in identifying areas for improvement. Originality/value - The contribution of this paper consists of: development of an instrument for the measurement of integration, validating the instrument against a criterion, and the identification of three dimensions of integration – communication, coordination, and affective relationship. The unique contributions of this paper are the validation of the instrument against a criterion and the identification of “affective relationship” as a dimension of internal supply chain integration.

Production management in New Zealand: is education relevant to practice?

Presents a report on a postal survey of production managers and production management academics carried out in New Zealand. The managers were asked questions about their tasks, responsibilities, and educational needs. The academics provided data on their teaching of production management. The survey particularly focused on the practical relevance of production management topics commonly taught in undergraduate courses of tertiary institutions. Survey results show that the practical relevance of production management education in New Zealand is significant, but there is room for improvement.

A framework for highly reusable simulation modeling: separating physical, information, and control elements

This paper presents a conceptual framework for simulation modeling which emphasizes model reusability. Reusability is achieved through the provision of separate modeling constructs for physical, information, and control/decision elements of a system. These constructs contribute to a modular environment in which the modeling elements, once created, can be stored in a modeling database and retrieved. While this framework can be implemented within traditional simulation modeling environments, an object oriented modeling environment appears to offer a potentially superior approach. >