Two-Facility Location Problem with Infinite Retrial Queue

This paper analyzes a two-facility location problem under demand uncertainty. The maximum server for the ith facility is It is assumed that primary service demand arrivals for the ith facility follow a Poisson process. Each customer chooses one of the facilities with a probability which depends on his or her distance to each facility. The service times are assumed to be exponential and there is no vacation or failure in the system. Both facilities are assumed to be substitutable which means that if a facility has no free server, the other facility is used to fulfill the demand. When there is no idle server in both facilities, each arriving primary demand goes into an orbit of unlimited size. The orbiting demands retry to get service following an exponential distribution. In this paper, the authors give a stability condition of the demand satisfying process, and then obtain the steady-state distribution by applying matrix geometric method in order to calculation of some key performance indexes. By considering the fixed cost of opening a facility and the steady state service costs, the best locations for two facilities are derived. The result is illustrated by a numerical example.

Backward and Forward Linkages in Chinese Steel Industry Using Input Output Analysis

This paper measures the direct and indirect contribution made by iron and steel industry in the economy of China and assess the differences between China and other steel producing countries. With this aim in view, the input-output modelling is used to detect the industrial linkages known as backward and forward linkages of eight iron and steel producing countries, including China, USA, Japan, Germany, Italy, Brazil, Korea, and India. The induction effect of export demand on steel industry in China is shown to be less than several OECD countries, such as Japan.

A Decision Support Architecture for Maritime Operations Exploiting Multiple METOC Centres and Uncertainty

Maritime operations are affected significantly by meteorological and oceanographic (METOC) conditions. The availability of multiple METOC centres able to deliver more accurate forecasts in the near future (2/3 days) is a promising resource toward better operational planning. However, how a specific maritime operation can benefit from such forecasts is not straightforward. A decision support architecture is required to combine METOC forecasts and human knowledge and select the best action from a set of pre-defined actions for the maritime operation. This paper describes a decision support architecture developed at the NATO Undersea Research Centre that is an improvement over a previous version in two ways: (1) it exploits forecasts coming from more than one METOC centre, and (2) it exploits uncertainty associated with METOC forecasts. The former allows for the exploitation of different abilities of METOC centres at different conditions. The latter allows for the propagation of input uncertainty on output products (the risks related to each action), thus allowing operators to assess if risks related to different actions are statistically different. Both features increase the robustness of the previous decision support architecture. The effectiveness of the new architecture is demonstrated on an underwater glider surfacing experiment carried out on data collected during a cruise in the Adriatic Sea in 2006.

Cost Framework for Evaluation of Information Technology Alternatives in Supply Chain

Organizations are often facing the problem of determining the degree of investment in building information links with their suppliers and buyers to reduce costs, lead times, and quality problems, improve timely customized delivery, increase asset utilization, and improve corporate profitability. One of the critical enablers for an efficient and effective supply chain is timely planning and information processing across the entire value-added chain. This paper presents an analytical model for selecting the right mix of analytical software and hardware alternatives at various planning and execution levels of an organization to remain competitive in a supply chain. Factors such as quality, reliability, flexibility, timeliness and organizational compatibility have been quantified into cost components that form the weighted cost function. The weights of the various cost components of software and hardware are derived from pair-wise comparison. These weights account for the relative importance of alternative supply chain strategies for an organization. A numerical example is presented to demonstrate the applicability of the proposed framework and exhibit the efficacy of the procedures and algorithms.

Optimal Thresholds of an Infinite Buffer Discrete-Time Two-Server System with Triadic Policy

This paper analyzes a discrete-time infinite-buffer Geo/Geo/2 queue, in which the number of servers can be adjusted depending on the number of customers in the system one at a time at arrival or at service completion epoch. Analytical closed-form solutions of the infinite-buffer Geo/Geo/2 queueing system operating under the triadic (0, Q N, M) policy are derived. The total expected cost function is developed to obtain the optimal operating (0, Q N, M) policy and the optimal service rate at minimum cost using direct search method. Some performance measures and sensitivity analysis have been presented.

Pricing and Replenishment Policies for Imperfect Quality Deteriorating Items under Inflation and Permissible Delay in Payments

Usually it is assumed that all items in a lot are of good quality, but in reality this assumption may not always be pertinent. Thus, the inspection of lots becomes essential in almost all organizations. Moreover, its role becomes more vital when the items are deteriorating in nature. Owing to this fact, this paper investigates the impact of initial inspection on retailer’s pricing and ordering policy for deteriorating items under inflation and permissible delay in payments using discounted cash flow approach over a finite planning horizon. Demand rate is assumed to be a function of selling price. The proposed model jointly optimizes the number of replenishments and price by maximizing the retailer’s total profit. Results have been demonstrated with the help of a numerical example, and sensitivity analyses are also presented to provide managerial insights into practice.

Maintenance Strategy Evaluation Using ANP and Goal Programming

An optimal maintenance strategy mix is necessary for increasing availability and reliability levels of production facilities without significantly increasing operational costs. The selection of maintenance strategies is a typical Multiple Criteria Decision-Making (MCDM) problem with conflicting goals. Consideration of interdependence among the criteria and alternative policies for maintenance strategy provides valuable cost savings and greater benefits for any hybrid flow systems. For any decision maker, it is convenient to prioritize the criteria of MCDM problems and goals of goal programming problems in fuzzy terms. This paper presents an integrated approach for maintenance policy selection, using fuzzy Analytic Network Process (ANP) within a Goal Programming, based on fuzzy preemptive priority where goal hierarchies are specified in different levels of fuzzy importance. To overcome the criticism of inconsistency, unbalanced scale of judgments and uncertainty in the pair-wise comparison process, criteria weights are determined using modified fuzzy LLSM method.

Searching for Pareto-Optimal Settlements in Negotiations

Decision-making analysts are generally familiar with the maximin and minimax criteria used in the selection of alternative courses of action when payoffs depend on different states of nature. This paper applies these criteria to the collaborative negotiation problem in which two parties negotiate the resolution of several issues each with defined payoffs, and where the alternative choices for each party are qualitative attributes or non-differentiable variables. The proposed method assumes that the negotiators do not know each other’s payoffs and are generally unwilling to disclose information about their preferences. The search procedure for Pareto-optimal settlements and the role of the mediator in assisting the parties to achieve an improved negotiated agreement are analyzed and illustrated through an example.

Effectiveness of Inter-Organizational Systems in Global Manufacturing

Enterprise Information Systems, such as Enterprise Resource Planning (ERP) systems, have been applied to integrate business processes within a global manufacturing enterprise. Recently, the inter-organizational systems are applied to assist in business data sharing and collaboration among enterprises based on the ERP application. However, their resource requirements and failure rates are high, and many enterprises are concerned about the Business-to-Business (B2B) effectiveness. In this research, the authors study global manufacturing enterprises, which developed their B2B systems with Taiwanese government sponsorship successfully. B2B effectiveness is evaluated through operational efficiency and profitability, while the business scale, Electronic Data Interchange (EDI) induced supplier numbers, and application scope are considered influencing factors. After the evidence of multiple regression models and non-parametric statistic testing, the results show that only the application scope has a significant impact on profitability. The authors discuss these results from the perspective of enterprise integration as well as the system application scope and give suggestions to global manufacturing enterprises that want to apply inter-organizational systems.

Optimal Ordering Strategy of a Replenishment Policy for Deteriorating Items under Retailer’s Partial Trade Credit Policy

This paper investigates the economic order quantity inventory model for a retailer under two levels of trade credit to reflect the supply chain management situation. It is assumed that the retailer maintains a powerful position and can obtain full trade credit offered by supplier, yet the retailer just offers the partial trade credit to customers. Under these conditions, the retailer can obtain the most benefits. This study also investigates the retailer’s inventory policy for deteriorating items in a supply chain management situation as a cost minimization problem. The present study shows that the annual total variable cost for the retailer is convex, that is, a unique solution exists. Mathematical theorems and algorithms are developed to efficiently determine the optimal inventory policy for the retailer. The results in this paper generalize some already published results. Finally, numerical examples are given to illustrate the theorems and obtain managerial phenomena.