European J. of Industrial Engineering (10 papers in press)

• On price increase and temporary price reductions with partial backordering
  by Sanjay Sharma 
  Abstract: In the previous researches, a generalized production - inventory model is considered along with the partial backordering i.e. the situation when a fraction of shortage quantity is not backordered. The work is extended for the case where any supplier offers a short-term price discount. An optimum special order quantity and the potential cost savings are obtained for different possible stock status at the time of replenishment of a special large order size. Similarly the case, in which a price increase is declared by the manufacturers/suppliers, is incorporated in the model. Numerical examples are provided in order to illustrate the formulation along with the sensitivity analysis.
  Keywords: Production – inventory model, partial backordering, temporary price reduction, price increase.
   
• A simulation study of registration queue disciplines in an outpatient clinic: a two-stage patient flow model
  by Daiki Min, Yuehwern Yih 
  Abstract: The purpose of this study is to provide a guideline for designing a hospital’s centralized registration process. This study examine two-stage patient flow and how registration queue disciplines affect the performance of clinic idle time and patient waiting time. We first identify and evaluate six factors (no-show rates, punctuality of patient arrivals, appointment schedule overlaps, block appointment, range of process variability among clinics and registration queue disciplines) that affect the process variability of patient flows. Second, we conduct a series of simulation experiments with three different queue disciplines: flow rate (FR) rule (we proposed), first-come-first-served (FCFS) and earliest due date (EDD). Simulation results show that the proposed FR rule improves system performance significantly.
  Keywords: two-stage patient flow, process variability, centralized registration, queue disciplines, simulation
   
• Optimal Lot Sizing for Deteriorating Items with Festival Pattern Demand and Uncertain Lead Time
  by Hui Ming Wee 
  Abstract: The ordering policy for the retailers and the suppliers system are influenced by lead time, deterioration and expiration date. In this study, we consider the supplier’s uncertain lead time and the customer’s festival pattern demand. The festival pattern demand has a characteristic of increasing demand during festive season followed by a decreasing demand immediately after the festive season. An algorithm is developed to derive replenishment policy such that the expected unit time profit is maximized. A numerical analysis of the coordinated and a non-coordinated policy are also presented for comparison.
  Keywords: deteriorating inventory; uncertain lead time; festival pattern demand; coordination
   
• Utility Function Based Patient Prioritization in the Emergency Department
  by David Claudio, Gül E. Okudan 
  Abstract: With the increased awareness of productivity problems in healthcare operations, many researchers have proposed the implementation of tools and methods developed in other fields to benefit healthcare delivery. Accordingly, in this paper we present an application of a decision making methodology, multi-attribute utility analysis, to healthcare. The sample problem presented as part of the application involves patient prioritization in an emergency department (ED), where several patients require immediate attention and they all have the same acuity level. Utility theory is selected for this application to appropriately account for the uncertainty in the decision problem.
  Keywords: utility functions; decision making; healthcare; Emergency Department; uncertainty; multi-attribute utility theory
   
• A fuzzy primal simplex algorithm and its application for solving the flexible linear programming problems
  by Hadi Nasseri 
  Abstract: One of the most interesting models of the linear programming is the flexible linear programming problem. It is shown that by using a suitable membership function for their constraints we can obtain an equivalent linear programming problem with fuzzy variables (FVLP). Some methods have been developed for solving these problems by introducing and solving certain auxiliary problems. Here, we propose a fuzzy primal simplex algorithm for solving the flexible linear programming problems. We emphasize that the fuzzy primal simplex method can solve the flexible linear programming problems directly without solving any auxiliary problem. This method will be useful for sensitivity analysis when using primal simplex tableaus too. We illustrate our method with some examples.
  Keywords: Flexible linear programming; fuzzy linear programming; membership function; trapezoidal fuzzy number
   
• A Decision-making Framework for Process Plant Maintenance
  by Devarun Ghosh, Sandip Roy 
  Abstract: An optimal maintenance approach is a key support to industrial production in the contemporary process industry. This paper presents a Multi-Criteria Decision-Making (MCDM) methodology for selecting the optimal mix of maintenance approaches – namely, corrective maintenance (CM), time-based preventive maintenance (TbPM) and condition-based predictive maintenance (CbPM) – for different equipments in a typical process plant. First, the criticality of each equipment from the point of view of maintenance is achieved by risk-ranking them (based on the worst-case failure mode), thus prioritizing them for maintenance interventions. Next, the MCDM methodology with a fuzzy adaptation of the Analytic Hierarchy Process (AHP) technique is applied to individual equipments. The criteria used as part of the MCDM model are safety, maintenance investment, business interruption loss and maintenance technique feasibility. Further, this technique is embedded into a Goal Programming (GP) model to optimize multiple objectives such as risk reduction and cost minimization, subject to resource constraints. Our analysis shows that CbPM would be the preferred choice, especially for equipments with high risk rankings and availability requirements, unless cost and feasibility constraints outweigh it as compared to TbPM and CM. If CM has a cost advantage over TbPM, it can be a viable maintenance policy only for less critical equipments (with comparatively low safety requirements) or for equipments with a high profit margin (where business interruption losses are not very critical). The present approach is an improvement over contemporary approaches to decision-making for maintenance management in that it integrates risk assessment with the GP-Fuzzy AHP technique and is sufficiently generalized. The approach can aid formulating a cost-effective maintenance approach for a plant.
  Keywords: Multiple-Criteria Decision Making, Fuzzy Analytic Hierarchy Process, Goal Programming
   
• Monte Carlo Simulation Methods for Dynamic Line Layout Problems with Nonlinear Movement Costs
  by Wai Kin Victor Chan, Charles J. Malmborg 
  Abstract: Monte Carlo simulation provides a risk management tool for solving line layout problems when material flow requirements change over time and/or are uncertain. This study demonstrates this capability for line layout problems where material handling costs are not directly proportional to distance traveled, e.g., where individual material moves impose a fixed cost which is amortized over the length of the move. Nonlinear movement costs are modeled using a movement “discount factor” imbedded in a Monte Carlo simulation model used to identify solutions performing at high, although not necessarily optimal, levels across a range of operating conditions. The procedure is demonstrated through a series of sample problems.
  Keywords: Line Layout, Materials Handling Volume Distance, Simulation
   
• Cooperative Hub Network Development
  by Frans Cruijssen, Peter Borm, Wout Dullaert, Herbert Hamers 
  Abstract: This paper introduces a framework for cooperative hub network development. Building a joint physical hub for transhipment of goods is expensive and therefore involves considerable risks for the cooperating companies. In a practical setting, it is unlikely that an entire network will be built at once. Rather, the partners will have a more cautious attitude and build the hub facilities one-by-one. In the proposed framework, every time a new hub is introduced, partners will have the opportunity to decide whether or not they participate (and thus invest) in this network extension.
  Keywords: Hub Networks; Horizontal Cooperation; Cooperative Game Theory
   
• Managing hidden system threats for higher production regularity using intelligent technological solutions: A case study
  by Jawad Raza, Jayantha P. Liyanage 
  Abstract: Identification and interpretation of hidden system threats on complex oil and gas production platforms has always been a challenge. These threats may gradually develop into failures/faults resulting in system shutdowns or eventually loss/reduction of production. Oil and gas industry is willing to test new technologies in managing uninterrupted, higher production regularity. In response to these challenges, a research project was initiated involving a leading oil company in Norway. A systematic investigative approach was adopted which incorporates domain experts’ opinion and multiple information resources/databases. The paper attempts neural network modelling of a critical production loss-related scenario, based on real plant data from an offshore production facility. Analytical results captured symptoms of suboptimal performance from compressors installed in the gas compression system. This methodology could give plant operators an opportunity to early identify system’s anomalies. As a result, unwanted shutdowns can be avoided, consequently improving overall plant’s efficiency and productivity.
  Keywords: Process anomalies, Artificial Neural Networks, Compressor performance, Production regularity
   
• Implementing Company Policy at Plant Level Asset Operations: Measuring Organizational Alignment
  by R.M. Chandima Ratnayake, Tore Markeset 
  Abstract: As the world becomes progressively more competitive and globalized, companies need to align their organization with the market and customers’ requirements. Such alignment needs to be based on organizational policies (i.e. strategic objectives, missions and goals) implemented in the products and plant level operations. However, to identify gaps, an integrated approach to measure the organizational alignment is needed. The measurements may be used to 1) link strategy goals towards daily activities; 2) identify relevant activities for continuous improvements; 3) obtain better internal alignment between employees, departments, production locations, etc.; as well as to 4) manage business processes. This paper discusses the measurement of organizational alignment with respect to a company’s policies. A generic model for management of the company’s alignment is suggested using the analytic hierarchy process. The model is demonstrated using a case study performed in an automobile manufacturing plant located in the USA.
  Keywords: company policy, organizational alignment, plant, asset operations, analytic hierarchy process