Andi Cakravastia

A two-stage model for the design of supply chain networks

Abstract This research aims to develop an analytical model of the supplier selection process in designing a supply chain network. The constraints on the capacity of each potential supplier are considered in the process. The assumed objective of the supply chain is to minimize the level of customer dissatisfaction, which is evaluated by two performance criteria: (i) price and (ii) delivery lead time. The overall model operates at two levels of decision-making: the operational level and the chain level. The operational level concerns decisions related to optimizing the manufacturing and logistical activities of each potential supplier in order to meet the customers requirements. At the chain level, all the bids from potential suppliers are evaluated and the final configuration of the supply chain is determined. The structure of the chain depends on the product specifications and on the customers order size. An optimal solution in terms of the models for the two levels can be obtained by using a mixed-integer programming technique.

Integrated model for supplier selection and negotiation in a make-to-order environment

The paper deals with the development of an integrated supplier selection and negotiation process for multiple parts/materials procurement. The main objective is to integrate decisions in the internal supply chain of a make-to-order manufacturer. Two main decisions during the negotiation process are considered: (1) the manufacturing planning decision responsible for determining the production schedule and fabrication lot size and (2) the supplier selection decision concerning which suppliers are selected for company business and the order volume allocated to each selected supplier. The model is designed to support the negotiation process by generating a set of effective alternatives in each negotiation period. Its structure is multi-objective and non-linear. The combination of the interactive weighted Tchebycheff method and Benders decomposition method is applied to generate a set of effective alternatives to support the decision-maker in each negotiation period.

Model for negotiating the price and due date for a single order with multiple suppliers in a make-to-order environment

The nature of the business of a make-to-order company complicates its procurement activities. This paper is concerned with the development of a model for price and due-date negotiations between a manufacturer and its multiple suppliers in fulfilling a single order from a customer in a make-to-order environment. The developed negotiation model incorporates several established negotiation theories: aspiration level, limit level, natural forces acting on a negotiator and effective alternatives. Instead of presenting a single alternative for an offer in the current round of negotiation, we apply the Interactive Weighted-Tchebycheff method to generate a set of effective alternatives for presentation to the decision-maker in each round of the negotiation process. By giving a set of alternatives, we provide a degree of freedom to incorporate the decision-makers preference in making offers and counter-offers during the negotiation process.

Supply chain strategy for high technology-content product and its consequences to technology transfer mechanism

The purpose of this article is to develop supply strategy of a company producing high technology-content product and subsequently to analyse the consequences of the strategy on technology transfer process that takes place on the company itself or between the company and its suppliers. Taking into consideration the extensive impact of globalisation on companys operation activities, the article focuses on Vertical Integration and Local Suppliers strategies on behalf of supply strategy in the global environment. Four supply chain factors are considered in the selection process of these two supply strategies, namely, country environment, competitive situation, company characteristic and extent of globalisation. Finally, this article describes dominant mechanisms of technology transfer as consequences of supply strategy.

Performance-based maintenance contract for equipments used in mining industry

In this paper, we study performance based maintenance contracts for dump trucks operated in a mining industry. The service contract is characterised by two dimensional limits - one limit representing age and the other limit usage. In a performance based service contract uses an attractive incentives to motivate the the agent to increase the equipments performance beyond the target, and this in turn gives benefit for both the owner of the trucks and the Agent of service contract. In this paper, we study performance based maintenance service contracts for equipment used in a mining industry and the equipment is sold with two dimensional warranties and the perfomances considered includes availability and safety measures. We consider a situation where an agent offers several service contract options and the owner of equipment has to select the optimal option. We obtain the optimal strategy (pricing structure) for the agent and the optimal option for the owner using a stackelberg game formulation in which the agent is as a leader and the owner as a follower.

Two Dimensional Maintenance Contracts for a Fleet of Dump Trucks Used in Mining Industry

In this paper, we study two dimensional maintenance contracts for a fleet of dump trucks operated in a mining industry. The two-dimensional contract is charaterised by two parameters (i.e. age and usage limits) which define a region. Two different shapes of the contract region are studied, where one region favors the customer, and the other the service provider. The maintenance service contracts studied is the performance based contract which offers incentives to motivate a service provider (an agent) to increase the equipment’s performance beyond the target. This in turn gives benefit for both the owner of the trucks and the agent of service contract. The decision problem under study is that an agent offers several two dimensional service contract options and the owner of the trucks has to select the optimal option. We use a Nash game theory formulation in order to obtain a win-win solution – i.e. the optimal strategy (pricing structure) for the agent and the optimal option for the owner.

Performance-based maintenance contract for a fleet of dump trucks used in mining industry

In this paper, we study two dimensional maintenance contracts for a fleet of dump trucks operated in a mining industry. We consider performance based service contracts which offer attractive incentives to motivate a service provider (an agent) to increase the equipments performance beyond the target. This in turn gives benefit for both the owner of the trucks and the Agent of service contract. The situation under study is that an agent offers several two dimensional service contract options and the owner of the trucks needs to select the optimal option. We use a stackelberg game formulation in which the agent is as a leader and the owner as a follower to obtain the optimal strategy (pricing structure) for the agent and the optimal option for the owner.

Optimization Models for Deriving Optimum Target of Key Characteristics

The aim of this research is to develop optimization models in deriving optimum target of key characteristic (KC). There are two kinds of product KCs introduced in this paper, namely performance and dimension product KC. The performance product KC target values must be determined by balancing customer and designer utilities subject to design cost and time provided by a company. The KCs of a product can be visualized using a KC flow-down which shows the hierarchical structure of the product. The flow-down may consist of many levels from product KC to process KC. Using axiomatic design as a methodology to map the flow-down, we conclude that product KC, assembly-components KC, and process KC are in functional domain, physical domain, and process domain respectively. In this paper, the objective function of the model for deriving optimum product KC target is to minimize utility gap between customer and designer subject to design cost and time. The assembly-component KCs have to be derived considering the product KC targets. In the absence of product KC target, the objective function of the model is to maximize the desired effect or minimizing the undesired effect. In the existence of product KC target, the objective function of the model is to attain the target considering technical constraints of the product. We use a shaft design problem as a numerical example to show the implementation of the models.

A buffer stock model to ensure price stabilization and availability of seasonal staple food by empowering producer using warehouse receipt system

Staple food that is produced by agro industry has salient supply disparity during the harvest and planting season. This situation could cause both staple food scarcity and price fluctuation. An indirect market intervention model is proposed to mitigate producers revenue loss when selling price plunges and to secure consumers need when staple food is scarce. The model uses buffer stock scheme in accordance with warehouse receipt system (WRS) and collateral management system. By using WRS, producer can pawn some of their staple food to the warehouse management and obtain receipt, then give the receipt to the Financial Institutions to access loan. Next, they can redeem their pawn and sell them under profitable price. Mixed-integer nonlinear programming (MINLP) approach has been used to determine the decision variables for producer and government. The result shows that the model can be used to solve problem.

A batch scheduling model for m heterogeneous batch processor

This research addresses a batch scheduling problem for single item parts with multi due date on m heterogeneous batch processors. The objective is to minimise total actual flowtime of parts through the shop. The total actual flowtime of parts in a batch is the multiplication of the interval between batch arrival time and the due date by the number of parts in the batch. Using the actual flowtime as the objective means it is oriented to satisfy the due date as a commitment to customers, and simultaneously to minimise the length of time of the parts spending in the shop. An algorithm to solve this problem is proposed.