International Journal of Operational Research (Int J Oper Res )

Description

IJOR is a fully refereed journal generally covering new theory and application of operations research (OR) techniques and models that include inventory, queuing, transportation, game theory, scheduling, project management, mathematical programming, decision-support systems, multi-criteria decision making, artificial intelligence, neural network, fuzzy logic, expert systems, and simulation. New theories and applications of operations research models are welcome to IJOR. Modelling and optimisation have become an essential function of researchers and practitioners in a networked global economy. New theory development in operations research and their applications in new economy and society have been limited. In the information intensive society and economy, decisions are made based on the analysis of data available. Operations research techniques and models need to be integrated with computers for the purpose of analysis, optimisation and application in decision making. This development has led the researchers and practitioners to look for new operational research models and their applications in global economy and society. For this purpose, the modelling and optimisation have become a paramount important. IJOR will act as a platform to encourage further research in OR and MS theory and applications. Globalisation of market and operations places a tremendous pressure in making timely and accurate decisions using the analysis of data and more accurate information. This signifies the importance of developing suitable operations research techniques and models and their applications are a paramount important in the 21st century global society and economy.

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  • 5-year impact
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  • Website
    International Journal of Operational Research website
  • Other titles
    International journal of operational research (Online), IJOR, Operational research
  • ISSN
    1745-7653
  • OCLC
    67616113
  • Material type
    Document, Periodical, Internet resource
  • Document type
    Internet Resource, Computer File, Journal / Magazine / Newspaper

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Nowadays, defining new projects is significantly vital and necessary for many organizations and companies. The problem arise here is how to select an appropriate portfolio from a set of candidate projects. A good combination of projects can extensively promote the organizations in their competitive performance. Thus, the purpose of this study is to present a practical model in addition to some solution approaches to choose the best and proper project portfolios with the considerations of projects’ interactions, quantitative and qualitative criteria, and practical constraints. A linear formulation has been proposed which considers the interaction effects and integrates the number of selected projects, the segmentations, and the budgetary constraints into a single set of constraints. In order to solve the proposed model, a genetic algorithm and also a differential evolution algorithm are presented. Moreover, the efficiencies of these two algorithms are compared with an exact method using various numerical examples. Finally, through a case study the performance of the model is demonstrated.
    International Journal of Operational Research 12/2014; In press.
  • [Show abstract] [Hide abstract]
    ABSTRACT: in this paper, we propose an integrated methodology of Fault-tree analysis (FTA) and the fuzzy analytical hierarchy process (AHP) approach, which provide means to integrate the qualitative and quantitative information to the group decision-making process for analyzing green supply chain risks under the fuzzy surroundings. In the proposed methodology, initially, a fault tree diagram is constructed, which includes the probable criteria, and sub-criteria of the green supply chain risks, and later, using the fuzzy AHP approach, these criteria and sub-criteria were prioritized for risk assessment. A total eight risk criteria and thirty sub-criteria were identified based on relevant literature and the experts input. The research findings illustrates that the product recovery risks and process risks criteria possess highest priority and need considerable managerial responsiveness for reducing the green supply chain susceptibility and hence performance improvement. Further, a plastic manufacturer green supply chain case illustrative example is presented to show the real-world applicability of the study. The managerial implications and conclusions are also discussed in the end.
    International Journal of Operational Research 04/2014;
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    ABSTRACT: At present, wireless communications are an integral part of day to day life. To make this communication effective and efficient, we have to place our transmitters in such a way that we can provide reliable service with a minimum cost. However, properly accomplishing this becomes a very difficult and computationally complex task when real-world considerations such as variation in signal strength due to distance and differences in the propagation environment (i.e., different degrees of obstruction) are taken into account. Therefore, the objective of this research is to develop effective and efficient methodologies to design an optimum wireless transmitter allocation strategy. To achieve this objective, we consider this decision problem as a grid-based location problem (GBLP), and develop an ILP model that is designed to provide the optimal solution for the transmitter location problem. These ILP models are often difficult to solve. As such, we developed a problem-specific decomposition approach to solve large-scale GBLP ILP problems, which we demonstrate has significantly reduced solution runtimes while not impacting optimality.
    International Journal of Operational Research 01/2014;
  • International Journal of Operational Research 01/2014; 19(2):32-42.
  • International Journal of Operational Research 01/2014; 21(3):365-390.
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    ABSTRACT: The present study is concerned with a machine repair problem with mixed standbys, permanent and additional repairmen. To deal with the realistic situation, the concepts of balking and reneging are also included. The operating units as well as standby units are assumed to fail in two modes. The units have exponential life time and repair time distributions. It is also assumed that there is a probability of a switching failure of the standby units to the operating state. The transient state probabilities are obtained by Runge-Kutta method. Some performance indices such as expected number of failed units, expected number of standby units, machine availability, etc., are obtained. To determine the expected total cost per unit time, a cost function has been facilitated. The numerical experiment is carried out to validate the analytical results of the developed model. The sensitivity analysis is also performed to explore the effect of different parameters on the performance indices. Keywords: mixed standby; balking; reneging; transient state probabilities; switching; failure modes; additional repairmen; Runge-Kutta method; machine repair systems; standby units; machine availability.
    International Journal of Operational Research 01/2014; 21(3):365-390.
  • International Journal of Operational Research 01/2014; 21(2):201-220.
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    ABSTRACT: The current paper analyses how the information gathering capabilities of consumers affect the patterns of technological innovation, establishing an explicit link among market demand, firms and the evolution of technology dynamics. We examine the effects that different decision theoretical driven demand structures may have on the incentives of firms to signal the existence of and introduce technologically superior products. We illustrate how the generation of technological niche markets depends on the ability of decision makers to reverse their information gathering processes and compare the goods observed in different markets before making a choice. In addition, we obtain equilibrium situations where the introduction of technologically superior products and subsequent generation of niche markets, i.e., climbing the technological quality ladder, is suboptimal for the signalling firm. Further, numerical simulations are introduced to illustrate the theoretical results obtained.
    International Journal of Operational Research 01/2014; 20(2):121 - 155.
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    ABSTRACT: Four multiresponse optimization problems were simulated under the RSM framework to describe real-life situations and provide a fair basis to compare the performance of optimization criteria built on different approaches. Different response types, feasible regions, number of responses and variables as well as adverse variance conditions were considered in each problem. Performance metrics usefulness to take more informed decisions about solution selection is also illustrated. An unusual graphical representation of the results provides useful information about working abilities and performance of tested criteria.
    International Journal of Operational Research 01/2014; (in press).
  • International Journal of Operational Research 01/2014;
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    ABSTRACT: In addition to the system’s complexity and uncertainty, healthcare managers face many challenges, including the increasing levels of demand and patient expectations at the time of more budget constraints enforced on healthcare service in Ireland. The delivery of a better patient care requires effective decision making especially in planning of healthcare resources. For an emergency department (ED) of a leading university hospital in the south of Dublin City, a decision support application for resource planning considering multiple performance indicators was developed. A comprehensive discrete event simulation model was used to identify the most significant variables and key factors that affect the ED performance. Combining this model with Taguchi orthogonal arrays and data envelopment analysis in an integrated manner helps to improve decision-making procedure in terms of systematic scenarios’ selection and evaluation. The developed system is used for resource planning and also to assess risks due to the shortage of medical staff of the emergency department. Results show the importance of balancing doctor numbers employed within ED in order to maintain reasonable patient throughput time.
    International Journal of Operational Research 01/2014; 19(1):40.