## OPSEARCH

OPSEARCH is the official journal of the Operational Research Society of India (ORSI) publishing the research papers in the field of operations research and related fields. It is a quarterly publication (March, June, September and December).

• a) official publication of the prestigious Operational Research Society of India
• b) premier Indian journal in the field of Operational Research

The journal OPSEARCH published by the Operational Research Society of India (ORSI) is a national forum set up with the objective of promoting the education and applications of Operational Research (OR) in day-to-day environment in business, industry and other organizations.

Related subjects » Business & Management - Mathematics - Operations Research & Decision Theory

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1. ### Abstract

In a multi-pass turning process, determination of the optimal values for different machining process parameters has already been identified as a complex optimization problem due to the involvement of numerous real time constraints. In this paper, six metaheuristics, such as artificial bee colony algorithm, ant colony optimization, particle swarm optimization, differential evolution algorithm, firefly algorithm and teaching–learning-based optimization algorithm are implemented to estimate the minimum unit production costs for two different part configurations while fulfilling a given set of machining constraints. It is observed that for both the cases, teaching–learning-based optimization algorithm supersedes the remaining optimization techniques with respect to various predetermined performance measures. Two statistical tests, i.e. paired t test and Wilcoxson signed rank test, also prove the uniqueness of this algorithm as compared to the others.

2. ### Abstract

Analytic hierarchy process (AHP) is a widely used multicriteria decision making method. Chang’s extent analysis method (EAM) is appeared as a very popular fuzzy AHP approach. The aim of this paper is to generalize the EAM in intuitionistic fuzzy settings for effective modeling of imprecision and uncertainty inherent in nature. In this paper, special triangular intuitionistic fuzzy degree of possibility is defined for comparing two or more triangular intuitionistic fuzzy numbers (TIFNs) and some relevant theorems are introduced generating intuitionistic fuzzy numbers as weights of criteria or performance scores of alternatives. Based on TIFNs, a conversion scale for linguistic variables is proposed for generating a triangular intuitionistic fuzzy preference relation. The EAM is then generalized in intuitionistic fuzzy settings by proposing generalized intuitionistic fuzzy EAM using TIFNs and its arithmetic for deriving crisp priority vector from the triangular intuitionistic fuzzy preference relation. The advanced approach is validated through two numerical examples.

3. ### Abstract

Banks are the financial intermediaries and important means for the advancement of economies. In the cutthroat competitions, the increase in market shares is a matter of concern for all. Banks are expected to increase their efficiency to boost competitive capacity, which also helps the Decision-maker to know about grey areas for development. Therefore, performance measurements of efficiency calculation, by using different methods are the concern for research across the world. This paper tries to use the combination of AHP, TOPSIS, and Grey Relational Analysis for efficiency calculation of different public sector banks in India and finally, results were compared. AHP is used to determine the weight criteria and Grey Relational Analysis and TOPSIS are used to rank the bank performances. The proposed method of this study used various inputs and outputs criteria which were taken from various banks annual reports. Descriptive statistics and correlation matrix were used to test the validity of the criteria. The findings reveal that banks which are considered as efficient are close to relative closeness to the ideal solution, expose an alternative ranking of the banks, present research also provides better insight to focus on the area of improvement in comparison to others banks. The Comparative result shows both models have the almost same interpretation. Little deviation in their ranks is due to methodological differences. The proposed research will provide a framework for further applications and both approaches will help decision maker of Indian Public sector banks to find optimal solutions to the complex problems by assessing various alternatives.

4. ### Abstract

This paper deals with a single server queueing system where the waiting space is limited. The server serves the customer in batches. The arrival process is considered to be renewal type and the services are considered to be correlated which has been presented by a continuous-time batch Markovian service process (C-BMSP). Distribution of the system length at pre-arrival instant of a customer and at an arbitrary-epoch have been determined for this queueing system. These probability distributions have been used for obtaining the blocking probability of an arbitrary customer, expected system-length, expected waiting time of an arbitrary customer in the system, and several other important performance measures. This model may find application in queueing systems involving inventory where delay in demand may lead to perishing of goods due to long wait in the system. Also, a profit function has been derived for such a queueing model to maximize the profit from the system for certain model parameters. Finally, assuming that the inter-arrival time follows phase-type distribution, a few numerical examples have been presented in the form of graphs and tables.

5. ### Abstract

Many organizations utilize information technology to gain competitive advantage. As the need for software increased, the number of software companies and the competition among them also increased. The software organizations in countries like India can no longer survive based on cost advantage alone. The companies need to deliver defect-free software on time within the budgeted cost. This paper is a case study on minimizing the delivered defect density by optimally executing the various phases in software development life cycle process. The implementation of the study on four projects has shown that the delivered defect density can be minimized by executing the software development process with optimum settings suggested by the methodology. The project managers can also utilize the approach to achieve the goals set on other important output characteristics like productivity, schedule, etc.

6. ### Abstract

We propose an interior point method to compute solution of linear complementarity problem LCP (qA) given that A is a real square hidden Z-matrix (generalization of Z-matrix) and q is a real vector. The class of hidden Z-matrix is important in the context of mathematical programming and game theory. We study the solution aspects of linear complementarity problem with $$A \in$$ hidden Z-matrix. We observe that our proposed algorithm can process LCP (qA) in polynomial time under some assumptions. Two numerical examples are illustrated to support our result.

7. ### Abstract

Human resources management (HRM) helps the organization to assess organizational and environmental changes related to its activities at minimum costs. Moreover, HRM ensures unity and coherence to personnel activities. Therefore, nowadays, the human resources strategies are considered to be the main components of organizations to get improvement. It is imperative to consider the strategies, in order to increase the effectiveness and efficiency of the management activities, and in order to develop the abilities of employees. In this regard, successful organizations are those organizations in which managers and employees, are always in a dynamic competition for innovation and creativity on the basis of their organization strategies, and also those organizations in with thinking among the forces have become a habit and a task. The present study tries to identify and prioritize the human resource strategies with an approach based on the creativity among the employees in administration of documents and properties registration departments. The analysis was conducted by the strengths, weaknesses, opportunities, and threats matrix. Then analytical network process multi-criteria decision making method is applied to prioritize the strategies. The strategy for the maintenance of human resources, based on the expanded creativity criterion, would be the first priority, along with its details.

8. ### Abstract

A production inventory model with linearly time dependent production rate to a certain period and then with constant production rate is developed in random time horizon under inflation and time value of money. It is assumed that time period i.e. business period is random and follows exponential distribution with known mean. Demand is linearly stock-dependent. With experience unit production cost decreases with cycles and a part of the set up cost decreases with time. Here also holding and set up costs are imprecise and the optimistic/pessimistic equivalent of fuzzy objective function is obtained by using possibility/necessity measure of fuzzy event. The model is formulated as a cost minimization problem for a production controlled inventory system and solved with the help of GRG (LINGO-14.0) technique(cf. Gabriel and Ragsdell in AMSE J Eng Ind 99:384–00, 1977). The results of the models are obtained for some numerical data and then presented in tabular forms. Some sensitivity analyses are presented for the expected total cost of a model with respect to demand, combined effect of inflation, the time value of money and mean value of time horizon distribution. In real-life the inventory parameters are uncertain. Here in general format, a production controlled inventory model is formulated with imprecise data and made crisp using fuzzy measures in both optimistic and pessimistic senses. It is shown numerically that cost in pessimistic sense is more than that in optimistic sense.

9. ### Abstract

The core competency of the healthcare system is to provide treatment and care to the patient. The prime focus has always been towards appointing specialized physicians, well-trained nurses and medical staffs, well-established infrastructure with advanced medical equipment, and good quality pharmacy items. But, of late, the focus is driven towards management side of healthcare systems which include proper capacity planning, optimal resource allocation, and utilization, effective and efficient inventory management, accurate demand forecasting, proper scheduling, etc. and may be dealt with a number of operations research tools and techniques. In this paper, a Markov decision process inventory model is developed for a hospital pharmacy considering the information of bed occupancy in the hospital. One of the major findings of this research is the significant reduction in the inventory level and total inventory cost of pharmacy items when the demand for the items is considered to be correlated with the number of beds of each type occupied by the patients in the healthcare system. It is observed that around 53.8% of inventory cost is reduced when the bed occupancy state is acute care, 63.9% when it is rehabilitative care, and 55.4% when long-term care. This may help and support the healthcare managers in better functioning of the overall healthcare system.

10. ### Abstract

To achieve safer machining environment, and minimize emission of harmful and toxic substances during electrical discharge machining (EDM) process along with improvement in its performance, this paper emphasizes on identifying the best parametric combination of a green EDM process using superiority and inferiority ranking (SIR) method. Decision making trial and evaluation laboratory method is also employed to visualize the interrelationships between the responses of the said process while splitting them into cause and effect groups. In this process, peak current, pulse duration, dielectric level and flushing pressure are the input parameters, while process time, relative tool wear ratio, process energy, concentration of aerosol and dielectric consumption are considered as the responses. The optimal parametric combination as derived employing the SIR method is validated with the help of developed regression equations for each of the responses, which show that the adopted approach outperforms the other popular optimization techniques in obtaining the best mix of the green EDM process parameters for having improved machining performance and less hazardous effects on the environment.

11. ### Abstract

Queueing systems experienced in real-life situations are very often influenced by negative arrivals which are independent of service process and cause the elimination of jobs from the system. Such a scenario occurs in computer network and telecommunication systems where an attack by a malicious virus results in the removal of some or all data files from the system. Along this direction many authors have proposed various killing processes in the past. This paper unifies different killing mechanisms into the classical single server queue having infinite capacity, where arrival occurs as renewal process with exponential service time distribution. The system is assumed to be affected by negative customers as well as disasters. The model is investigated in steady-state in a very simple and elegant way by means of supplementary variable and difference equation technique. The distribution of system-content for the positive customers is derived in an explicit form at pre-arrival and random epochs. The influence of different parameters on the system performance are also examined.

12. ### Abstract

This paper examines a continuous review inventory model for perishable items with two demand classes. Demands for both classes occur according to Poisson process. The items in inventory are perishable products and have exponential lifetimes. The time after placing an order is an exponential random variable. When the on-hand inventory drops to pre-specified level s, only the priority customer demands are met whereas the demands from ordinary customers are lost. And also, the demand occurring stock-out periods are lost. The inventory system is characterized by continuous-time Markov process and steady-state probabilities are derived. The expected cost function is formulated and a numerical study is provided for optimization.

13. ### Abstract

In today’s technology-driven world, despite of efficient planning of manufacturing system and development of refined production technologies and control systems; the items produced in a manufacturing system may have some fraction of defectives. Thus inspection of a lot of the items is essential to differentiate perfect and imperfect products. Every business sector has some hidden costs involved in additional managerial cost which are also imperative to calculate for smooth running of the business sector. This work considers an entropic order quantity model with selling price dependent demand and screening to separate imperfect quality products. We find an important observation about effect of entropy cost on the maximization of profit which states that the entropy cost has similar behavior as the selling price of the product. Our findings enlighten the insights of the entropic order inventory model and enrich the advancement of the literature of inventory model. Finally, a hypothetical numerical example is set to validate the model and sensitivity analysis has also been performed to study the impact of various parameters on the optimal solution.

14. In the original published article the “Conclusion and future scope” paragraph has been incorrectly published.

15. ### Abstract

In this paper, the problem of elective surgery scheduling is studied, and resources like surgeons, nurses and operating rooms (ORs) are considered. The problem is to assign surgeries to operating rooms in order to meet three goals: (1) maximizing the number of surgeries that can be done using given fixed resources, (2) minimizing the total fixed costs and overtime costs of the ORs, and (3) minimizing the maximum of completion time of operating rooms. We take into account the uncertainty with the stochastic parameter for the regular operating time of OR in model and fuzzy constraint for resources and overtime. A multi-objective model is proposed to choose the operations to be scheduled on the selected day, and to assign the elective surgeries to OR sessions. In the first phase, we formulated a fuzzy robust optimization model and in the second phase, the sensitivity of the model to different values for penalties in the objective function, is analyzed. The efficiency of the proposed solution is validated by numerical results of applying the model to the case of a public hospital in Iran.

16. ### Abstract

Cellular manufacturing is a vital part of lean manufacturing. It is an application of group technology. Three problems in cellular manufacturing are cell formation, machine layout and cell layout problems. However, these problems are NP-hard optimisation problems and cannot be solved using exact methods. A difficult part is to form the machine groups or cells, also called Cell Formation Problem and several techniques have been proposed to solve the same. In this paper, the Cell Formation Problem is solved using an integrated approach of heuristics along with Genetic Algorithm and Membership Index. Heuristics technique is used for domain selection which is used in Genetic Algorithm as the initial population. Genetic Algorithm is useful for optimising the results of machine assignment to cells, and Membership Index is used to assign parts to the cells. The performance is analysed using performance measures such as group technology efficiency and some exceptional elements. The proposed computational methodology is tested on standard problems of diverse size from literature papers using the hybrid approach. Results from test problems show that the proposed method is effective and efficient. The paper is useful from the practicality aspect and also relevant from current research and industry trends.

17. ### Abstract

The establishment of contracts pursues the efficient fulfillment of supply chain members’ needs. However, this is not always possible due to market features and, more interestingly, the additional constraints that such mechanisms impose. Trust relationships, that we define as the absence of contracts, appear as a mean to deal with situations where contracts block decision making. Although trust enhances production/management activities, it is not clear how the absence of contracts impact on delivery times, which we investigate in this paper. We analyze a decentralized supply chain where a manufacturer needs an intermediate input, but typical suppliers that have a contract with the manufacturer do not provide it; so, he establishes a non-contractual relationship with an “external” provider. We model this interaction as a two-stage game and show necessary and sufficient condition to guarantee the existence and uniqueness of the Sub-game perfect Nash equilibria. Also, we show the relationship between delivery times and input’s requisition, at equilibrium, with exogenous variables like production costs and base revenue. We find that intuitive relationships hold when the requisition cost is higher than a third of the manufacturer’s revenue.

18. ### Abstract

Public distribution system (PDS) is the lifeline of food security in India which involves provisioning of foodgrains. To manage this supply chain more efficiently, an effective performance management system is a pre-requisite. This paper utilises the performance objectives-productivity approach to formalise a performance measurement methodology for the PDS supply chain of foodgrains at state level. Here, the actual values of the performance measures are compared with the objectivated values to arrive at the productivity index which indicates the degree of performance of PDS and its various components. In this model the optimal values of the “objectivated output” can be obtained either by solving a goal programming model or through benchmarking in the multi attribute utility theory framework. As fast movement of foodgrains is vital to reduce the degree of perishability due to losses during transit and storage, this multi-dimensional performance measurement system also rates the losses of foodgrains during various stages of freight transportation with a view to minimise the same. The primary aim in applying this method is to arrive at a benchmarking technique to assess if such supply chain is working effectively and efficiently which is akin to auditing the system. By using the given approach some standardisation could be brought into arrive at the authentic performance level of the PDS.

19. ### Abstract

The electric vehicle (EV) technology has been getting momentum due to rapid depletion of fossil fuels and also in taking care of environment. Many manufacturers are investing a lot in electric vehicles for a particular outcome coming from it which can show a sign for replacement of conventional I.C engines. They are taking interest about the customer findings in a car. There are various factors which affect the performance of an electric vehicle such as battery capacity, charging time, price, driving range etc. As we know there are many electric vehicle models that are present in market with different combinations and this study is based on the performance evaluation of electric vehicles using multiple criteria decision making tool from customer point of view. This study highlights the best electric vehicle model in Asian market so that findings of an EV buyer can be fulfilled. Fuzzy analytic hierarchy process has been used to determine criteria weight whereas evaluation of mixed data has been used for performance evaluation and ranking. According to the study BYD E6 becomes the best electric vehicle model in Asian market.

20. ### Abstract

In this paper, we develop a model to assign airplane seats to ordinary passengers to minimize their boarding time while some seats have been reserved earlier by high priority passengers. Our proposed mixed integer programming model assigns ordinary passengers to seats based on the amount of their carry-on bags and results in the minimum time to complete boarding of the airplane. The proposed model can result in 5% to 20% reductions in the average boarding time compared to the situation when passengers’ luggage is not considered.