Template-Type: ReDIF-Article 1.0 Author-Name: Siti Norida Wahab Author-X-Name-First: Siti Norida Author-X-Name-Last: Wahab Author-Name: Yan Feng Lay Author-X-Name-First: Yan Feng Author-X-Name-Last: Lay Author-Name: Wui Lim Koay Author-X-Name-First: Wui Lim Author-X-Name-Last: Koay Author-Name: Amir Aatieff Amir Hussin Author-X-Name-First: Amir Aatieff Amir Author-X-Name-Last: Hussin Title: Usage of pedestrian bridges among the urban commuters in Kuala Lumpur: a conceptual analysis and future direction Abstract: Pedestrian bridges are one of the safest crossing facilities, allowing pedestrians to cross the road by diverting away from traffic. However, the usage of pedestrian bridges has not been popular in Malaysia. Dreadful conditions of pedestrian bridges further contribute to the low usage. The main aim of this research is to develop a conceptual model to identify the motivating factors affecting the usage of pedestrian bridges among urban commuters in Kuala Lumpur. Four factors were identified from an extensive review of literature to construct the model namely safety, attitude, facilities and convenience. This study serves valuable information for scholars to further study and analyse topic relating to the use of pedestrian bridges. From the practitioner's point of view, this study provides valuable information to policy makers and government authorities to integrate and focus on the most motivating factors that could attract more users into utilising pedestrian bridges. Journal: Int. J. of Operational Research Pages: 352-372 Issue: 3 Volume: 41 Year: 2021 Keywords: pedestrian bridge; urban travelling environment; urban commuters; mobilities. File-URL: http://www.inderscience.com/link.php?id=116249 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:3:p:352-372 Template-Type: ReDIF-Article 1.0 Author-Name: S. Mahalakshmi Author-X-Name-First: S. Author-X-Name-Last: Mahalakshmi Author-Name: A. Arokiasamy Author-X-Name-First: A. Author-X-Name-Last: Arokiasamy Title: A new particle swarm optimisation variant-based experimental verification of an industrial robot trajectory planning Abstract: A new variant of particle swarm optimisation (PSO), constriction coefficient neighbourhood varying inertia weight varying acceleration coefficients particle swarm optimisation (CNVIWVAC PSO) and a conventional differential evolution (DE) algorithms are proposed in this work to do optimal time - mechanical energy trajectory planning for an industrial robotic manipulator (MTAB ARISTO 6XT). Three pick-and-place operations are considered. Minimisation of travelling time of robot end effector and mechanical energy of the actuators are considered as objective functions. This is to ensure fast execution of the desired operation in a minimum possible spending of mechanical energy. All kinematic and dynamic constraints such as position, velocity, acceleration, jerk and torque bounds are considered to ensure smooth as well as practical trajectory. Two stationary obstacles are considered in the path robot manipulator. A comparative analysis of proposed algorithms (DE and CNVIWVAC PSO) with a point-to-point (PTP) algorithm (own system of the MTAB ARISTO 6XT robot) has been carried out by means of experimental tests. The proposed algorithms have been evaluated and experimentally validated. The results proved that the proposed algorithms are better than the existing system (PTP) of robot. Journal: Int. J. of Operational Research Pages: 399-422 Issue: 3 Volume: 41 Year: 2021 Keywords: industrial robot; MTAB ARISTO 6XT robot; pick and place operation; minimum time-energy trajectory planning; DE; CNVIWVAC PSO. File-URL: http://www.inderscience.com/link.php?id=116250 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:3:p:399-422 Template-Type: ReDIF-Article 1.0 Author-Name: Subrata Kumar Patra Author-X-Name-First: Subrata Kumar Author-X-Name-Last: Patra Author-Name: Tilak Raj Author-X-Name-First: Tilak Author-X-Name-Last: Raj Author-Name: B.B. Arora Author-X-Name-First: B.B. Author-X-Name-Last: Arora Title: An analysis and modelling of selected barriers for a sustainable manufacturing system using ISM technique Abstract: Traditional manufacturing is largely focused on economics but are attributable for environmental degradation, ecological imbalance and several other negative connotations. To cope up with these challenges, manufacturers have to adopt manufacturing practices amenable to sustainable manufacturing system (SMS). However, transitioning to SMS is a challenging task because a gamut of complex barriers hinders its successful implementation. Data extracted from the reviewed literatures and aptly complimented by the responses of experts, helped in identifying various barriers that are considered as critical from sustainability viewpoint. A focused group discussion (FGD) group consisting of a few experts from steel industry prepared a questionnaire incorporating these barriers. An analysis using interpretive structural modelling (ISM) reveal that lack of government support towards developing new technologies is the most important barrier towards the attainment of SMS. Insights from this analysis will benefit decision-makers in formulating suitable strategies to mitigate the ill-effects of these barriers. Journal: Int. J. of Operational Research Pages: 373-398 Issue: 3 Volume: 41 Year: 2021 Keywords: traditional manufacturing; barriers; sustainable development; sustainability; sustainable manufacturing system; SMS; interpretive structural modelling; ISM; transitivity. File-URL: http://www.inderscience.com/link.php?id=116251 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:3:p:373-398 Template-Type: ReDIF-Article 1.0 Author-Name: K. Mathiyazhagan Author-X-Name-First: K. Author-X-Name-Last: Mathiyazhagan Author-Name: Sarthak Ahuja Author-X-Name-First: Sarthak Author-X-Name-Last: Ahuja Title: Modelling the sustainable supply chain management practices in Indian industries: a business model using the fuzzy TOPSIS approach Abstract: Worldwide customers have awareness for the use of eco-friendly products, and rules and regulations imposed by government to move towards the sustainable products create pressure impacts on the industries. The objectives of this study are to develop model and prioritise major sustainable supply chain management (SSCM) practices in Indian industries with a specific focus towards automobile, textile and food sectors. The 19 SSCM practices from the literature review and discussion with experts were considered. The fuzzy technique of order preference for similarity to ideal solution (TOPSIS) has been used to rank. Results shows that practices ISO 14000 and 14001 certification, value stream mapping and corporate social responsibility have been ranked as the topmost priority while taking decisions to ensure perfect sustainability in supply chains. Journal: Int. J. of Operational Research Pages: 324-351 Issue: 3 Volume: 41 Year: 2021 Keywords: sustainable supply chain management; SSCM; practices; case study; Indian industries; fuzzy TOPSIS. File-URL: http://www.inderscience.com/link.php?id=116252 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:3:p:324-351 Template-Type: ReDIF-Article 1.0 Author-Name: G. Ayyappan Author-X-Name-First: G. Author-X-Name-Last: Ayyappan Author-Name: S. Karpagam Author-X-Name-First: S. Author-X-Name-Last: Karpagam Title: An M[X]/G(a, b)/1 queueing system with unreliable server, stand-by server, restricted arrivals and variant threshold policy for vacations Abstract: We studied the behaviour of an <i>M</i><SUP align="right"><SMALL>[<i>X</i>]</SMALL></SUP>/<i>G</i>(<i>a</i>, <i>b</i>)/1 queueing system with unreliable server, stand-by server, restricted admissibility and variant threshold policy for vacations in this paper. The stand-by server is utilised only during main server's repair period. At the moment of main server's busy completion or repair completion, if the number of customers in the queue is less than '<i>a</i>', the main server avails type-I vacation repeatedly until the queue length reaches at least '<i>a</i>'. While getting back from vacation of type-I, if the queue has its length of value as at least '<i>a</i>' then the server performs the type-II vacation continuously, until it reaches at least <i>N</i>(<i>a</i> < <i>b</i> &le; <i>N</i>). When both types of vacation gets completed, and the length queue is at least '<i>N</i>', then the server starts service to the batch of '<i>b</i>' customers. The PGF of queue size and some important performance measures are derived. An extensive numerical result is illustrated. Journal: Int. J. of Operational Research Pages: 299-323 Issue: 3 Volume: 41 Year: 2021 Keywords: general bulk service; non-Markovian queue; unreliable server; stand-by server; restricted arrivals; variant threshold policy for vacations. File-URL: http://www.inderscience.com/link.php?id=116253 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:3:p:299-323 Template-Type: ReDIF-Article 1.0 Author-Name: Supriyo Roy Author-X-Name-First: Supriyo Author-X-Name-Last: Roy Author-Name: R.P. Mohanty Author-X-Name-First: R.P. Author-X-Name-Last: Mohanty Title: Optimising a production plan for underground coal mining: a genetic algorithm application Abstract: Developing an optimal production plan of an underground coal mine is complex due to several factors such as: economic, physical, environmental and social, etc. In this paper, an attempt has been made to apply genetic algorithm (GA) to maximise net present value (NPV) of a real life underground coal mine. It is first highlighted that the inefficacy of using direct optimisation methods and then a numerical illustration shows the efficacy of application of bio-inspired computation approach; because of its multiple advantages such as simplicity, user friendliness and parallel processing. This paper establishes the proposition that 'simulation-based stochastic optimisation for underground mine production plan would lead to better results than optimisation based on customary gradient optimisation approach'. Journal: Int. J. of Operational Research Pages: 423-445 Issue: 3 Volume: 41 Year: 2021 Keywords: underground coal mining; production planning; optimisation; evolutionary search; genetic algorithm. File-URL: http://www.inderscience.com/link.php?id=116264 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:3:p:423-445 Template-Type: ReDIF-Article 1.0 Author-Name: Imen Ben Abdelwahed Author-X-Name-First: Imen Ben Author-X-Name-Last: Abdelwahed Author-Name: Faouzi Trabelsi Author-X-Name-First: Faouzi Author-X-Name-Last: Trabelsi Title: Fuzzy expectation-spread-skewness model for Shariah-compliant portfolio optimisation Abstract: It is well known that fuzzy portfolios are very useful for investors who are looking for a path to manage risk when dealing with their long-term investment portfolio. In this paper, we propose a new framework to portfolio selection problem based on fuzzy theory in the context of Islamic finance. In order to measure how much an investor satisfies with his profit, skewness is adopted in addition to the first two moments of the distribution. We formulate a new fuzzy (Shariah-compliant) portfolio optimisation problem, referred as 'fuzzy expectation-spread-skewness (𝔽𝔼 - Sp - S) model'. We discuss the existence of the optimal solution. Besides, we provide numerical methods to approximate the solution, following in parallel probabilistic and analytical approaches. Some examples of application are also studied. Finally, we compare the followed numerical approaches and we state some financial interpretations. Journal: Int. J. of Operational Research Pages: 447-476 Issue: 4 Volume: 41 Year: 2021 Keywords: fuzzy portfolio; Shariah-compliant portfolio; fuzzy expectation; spread; skewness; triangular fuzzy variable; trapezoidal fuzzy variable; analytical approach; probabilistic approach. File-URL: http://www.inderscience.com/link.php?id=117069 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:4:p:447-476 Template-Type: ReDIF-Article 1.0 Author-Name: Elangeeran Malar Author-X-Name-First: Elangeeran Author-X-Name-Last: Malar Author-Name: P. Deepan Chakravarthi Author-X-Name-First: P. Deepan Author-X-Name-Last: Chakravarthi Title: Extreme learning machine-based investigation on automated detection of architectural distortion in mammograms Abstract: Breast cancer, having its origin from the breast tissue is usually detected by mammographic screening. The early detection of breast cancer reduces the mortality rate. A subtle type of breast cancer that often leads to misinterpretation by radiologists is architectural distortion. Though the existing computer aided diagnosis systems efficiently and effectively detect the presence of micro-calcification and masses, the diagnosis of architectural distortion lacks a promising method. This project attempts to detect and classify the regions of mammograms having architectural distortion. MIAS and DDSM database images are enrolled in this research work. 350 region of interests (ROIs) of each architectural distortion and normal cases were extracted. They were subjected to a filtering process, followed by contrast enhancement. Application of Gabor filter to the images resulted in orientation differences between the normal and abnormal images. Statistical features extracted from the resulting images were classified using extreme learning machine classifier. The experimental results obtained from extreme learning machine in comparison with support vector machine had an accuracy of 98.49% and 87.21% for MIAS and DDSM respectively. The accuracy of combined database of which is 85.38%. Journal: Int. J. of Operational Research Pages: 477-491 Issue: 4 Volume: 41 Year: 2021 Keywords: breast cancer; architectural distortion; AD; extreme learning machine; ELM; support vector machine; SVM; Gabor filter. File-URL: http://www.inderscience.com/link.php?id=117070 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:4:p:477-491 Template-Type: ReDIF-Article 1.0 Author-Name: S. Pradhan Author-X-Name-First: S. Author-X-Name-Last: Pradhan Author-Name: U.C. Gupta Author-X-Name-First: U.C. Author-X-Name-Last: Gupta Title: Stationary distribution of an infinite-buffer batch-arrival and batch-service queue with random serving capacity and batch-size-dependent service Abstract: In traditional batch-service queueing systems, the mean service time of batches are generally assumed to be constant. However, in numerous applications this assumption may not be appropriate. In telecommunication networks, the transmission rates depend on the number of packets in the batch which can be framed as batch-size-dependent service queue. The objective of this paper is to focus on both queue and server content distribution in an infinite-buffer batch-arrival and batch-service queue with random serving capacity rule and batch-size-dependent service. After deriving a bivariate probability generating function of queue length and server content distribution at departure epoch of a batch, we extract the complete joint distribution in terms of roots of the characteristic equation. We also obtain the system as well as queue length distribution at arbitrary epoch. Finally, a significant number of numerical examples are appended to show the feasibility of the analytic procedure and results where the occurrence of multiple roots have been dealt without facing any difficulty. At the end, a graphical representation of cost of the system shows that batch-size-dependent service is more significant as compared to batch-size-independent service. Journal: Int. J. of Operational Research Pages: 1-31 Issue: 1 Volume: 40 Year: 2021 Keywords: batch-arrival; batch-size-dependent; random serving capacity; supplementary variable; queueing; joint distribution. File-URL: http://www.inderscience.com/link.php?id=111951 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:1:p:1-31 Template-Type: ReDIF-Article 1.0 Author-Name: Kamran S. Moghaddam Author-X-Name-First: Kamran S. Author-X-Name-Last: Moghaddam Author-Name: Jalil Kianfar Author-X-Name-First: Jalil Author-X-Name-Last: Kianfar Title: Fuzzy bi-objective model for hazardous materials routing and scheduling under demand and service time uncertainty Abstract: We develop a fuzzy-based bi-objective optimisation model for hazardous materials (hazmat) vehicle routing and scheduling problem with time windows. The task is to find optimal links and routes to maintain a balance between safe and fast distribution of hazmats between origins and destinations through a transport network. We consider unknown probabilities for hazmat incidents along with a game-theoretic demon approach in a link-based model. Using the Nash game theory approach, an integrated routing and scheduling hazmat shipment problem is formulated. Since the formulated problem is a bi-objective model with travel time and population risk objectives, we also propose a solution method based on a hybrid Monte-Carlo simulation and fuzzy goal programming to obtain the set of Pareto optimal solutions. Computational results of a carefully crafted numerical example are also provided to illustrate the effectiveness of the developed mathematical model and the solution method in obtaining Pareto-optimal solutions. Journal: Int. J. of Operational Research Pages: 535-568 Issue: 4 Volume: 41 Year: 2021 Keywords: hazardous material; VRPTW; fuzzy multi-objective optimisation; fuzzy goal programming; FGP. File-URL: http://www.inderscience.com/link.php?id=117071 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:4:p:535-568 Template-Type: ReDIF-Article 1.0 Author-Name: Rahim Khanizad Author-X-Name-First: Rahim Author-X-Name-Last: Khanizad Author-Name: Gholam Ali Montazer Author-X-Name-First: Gholam Ali Author-X-Name-Last: Montazer Title: A model for optimal allocation of human resources based on the operational performance of organisational units by multi-agent systems Abstract: Optimal allocation of human resources is studied in this research. To solve the problem, a model of negotiation between intelligent agents is used in this study. Organisational units are considered as agents that seek for their benefits and use negotiation for human resources and job distribution. We firstly introduce operational performance level to find out how units can guarantee their performance. As a result, in this research, organisational decision making is managed in two levels by agents. In medium level, agents negotiate each other using optimal function to divide human resources optimally. Therefore, the final agreement will be distributed among the organisation using the special function developed for this reason. Results have shown that organisational units' operational performance is a good criterion for human resources distribution in organisation. Journal: Int. J. of Operational Research Pages: 32-51 Issue: 1 Volume: 40 Year: 2021 Keywords: human resources allocation; intelligent agents; negotiation; optimality; operational performance. File-URL: http://www.inderscience.com/link.php?id=111952 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:1:p:32-51 Template-Type: ReDIF-Article 1.0 Author-Name: Qiang Deng Author-X-Name-First: Qiang Author-X-Name-Last: Deng Author-Name: Zhaotong Lian Author-X-Name-First: Zhaotong Author-X-Name-Last: Lian Author-Name: Qi Fu Author-X-Name-First: Qi Author-X-Name-Last: Fu Title: A novel method of variable selection in data envelopment analysis with entropy measures Abstract: In data envelopment analysis (DEA) modelling applications, analysts typically experience difficulty in choosing variables when the number of variables is greater than the number of decision-making units (DMUs). In this paper, we develop a novel method to facilitate variable selection in DEA using entropy theory to avoid information redundancy. A numerical analysis is provided to compare our method to those of related studies. The results show that our proposed method produces a lower Akaike information criteria (AIC) value than other approaches. By presenting a real-world case, we show that this new method yields useful managerial results. Journal: Int. J. of Operational Research Pages: 514-534 Issue: 4 Volume: 41 Year: 2021 Keywords: data envelopment analysis; variable selection; entropy theory; Akaike information criteria; AIC. File-URL: http://www.inderscience.com/link.php?id=117072 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:4:p:514-534 Template-Type: ReDIF-Article 1.0 Author-Name: Abdullah Abdulaziz Alkhoraif Author-X-Name-First: Abdullah Abdulaziz Author-X-Name-Last: Alkhoraif Author-Name: Patrick McLaughlin Author-X-Name-First: Patrick Author-X-Name-Last: McLaughlin Title: A methodology to surface aspects of organisational culture to facilitate lean implementation within SMEs Abstract: The purpose of this paper is to provide an instructional guidance on how to surface aspects of organisational culture (OC) that effect lean implementation within small and medium sized manufacturing organisation. This paper describes how grounded theory and action research can be used inside each other. The paper suggests to not only using a translation method to validate the result but to use also inter-rate reliability to increase the validity and reduce the subjectivity. The paper also demonstrates how different technique can help management research by including in a time effective way. Journal: Int. J. of Operational Research Pages: 52-91 Issue: 1 Volume: 40 Year: 2021 Keywords: lean implementation; LI; organisational culture; OC; grounded theory; action research; small and medium-sized enterprises; SMEs. File-URL: http://www.inderscience.com/link.php?id=111953 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:1:p:52-91 Template-Type: ReDIF-Article 1.0 Author-Name: Luis-Angel Cantillo Author-X-Name-First: Luis-Angel Author-X-Name-Last: Cantillo Author-Name: Víctor Cantillo Author-X-Name-First: Víctor Author-X-Name-Last: Cantillo Author-Name: Pablo A. Miranda Author-X-Name-First: Pablo A. Author-X-Name-Last: Miranda Title: Optimisation approach to solve the truck loading and delivery problem at long haul distances with heterogeneous products and fleet Abstract: This paper proposes a sequential optimisation approach for addressing a complex real world problem of dispatch planning and freight loading for a set of highly irregular products with a heterogeneous fleet of trucks. The approach focuses on the case of goods with 'low-density values', highly varied with large travel distances. The proposed approach is based on a two-phase strategy: the first optimises the space assignment process inside trucks to each type of product. It is achieved by minimising long-haul transportation costs as a function of the fleet size and capacity, considering a set of predefined feasible and efficient loading solutions or patterns. The second phase minimises the number of visits per truck, assuming a fleet with fixed size and capacities for each type of product, which is determined in the first stage. The approach was successfully applied to a rolled steel company in Colombia, whose results show that the proposed model efficiently addresses the analysed problem, which is reflected in reasonable solution times and costs from a practical implementation perspective. Journal: Int. J. of Operational Research Pages: 92-116 Issue: 1 Volume: 40 Year: 2021 Keywords: truck loading; long-haul dispatching; heterogeneous fleet; irregular shape products; multi-commodity; big data. File-URL: http://www.inderscience.com/link.php?id=111954 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:1:p:92-116 Template-Type: ReDIF-Article 1.0 Author-Name: Noura Yassine Author-X-Name-First: Noura Author-X-Name-Last: Yassine Title: The EOQ model with items of imperfect quality and replenishment from different suppliers Abstract: The classical economic order quantity model is extended to the case where the items may be acquired from various suppliers. It is assumed that any lot size received from a supplier contains perfect and imperfect quality items. The percentage of perfect quality items in a lot size is a random variable having a known probability distribution. The imperfect quality items are detected through a 100% screening process conducted at the start of the inventory cycle. When the screening process is concluded, the imperfect quality items are sold in one batch at a discounted price. A mathematical model is developed to determine the total profit function. The optimal order quantity and proportions of the order acquired from the suppliers are obtained by maximising the total profit function. Iterative numerical algorithms that determine the optimal solution are proposed. Numerical examples are presented to illustrate the calculations in the case when the percentages of imperfect quality items follow the uniform distribution. Journal: Int. J. of Operational Research Pages: 117-136 Issue: 1 Volume: 40 Year: 2021 Keywords: constraint optimisation; optimal lot size; probability distribution; imperfect quality items. File-URL: http://www.inderscience.com/link.php?id=111955 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:1:p:117-136 Template-Type: ReDIF-Article 1.0 Author-Name: P. Aravind Author-X-Name-First: P. Author-X-Name-Last: Aravind Author-Name: V. Veeramani Author-X-Name-First: V. Author-X-Name-Last: Veeramani Author-Name: S.M. Girirajkumar Author-X-Name-First: S.M. Author-X-Name-Last: Girirajkumar Title: A hybrid state feedback controller design for two different dynamic systems Abstract: This paper deals the application of error recursive reduction computational (ERRC) technique to improve the performance of state feedback (SF) with integral control design. To highlight the performance of the proposed method is tested on second order and third order system. A second order system is framed based on general assumptions and the third order system is a model of the aircraft pitch control system. The proportional and integral control gain values are obtained using Ackermann's method. Results of with and without ERRC in state feedback design are compared. The controller performance was verified in terms of rise time, settling time, overshoot and tolerance limits. Journal: Int. J. of Operational Research Pages: 569-576 Issue: 4 Volume: 41 Year: 2021 Keywords: ERRC method; state feedback; state space; higher order systems. File-URL: http://www.inderscience.com/link.php?id=117075 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:4:p:569-576 Template-Type: ReDIF-Article 1.0 Author-Name: Sobhgol Gholipour Author-X-Name-First: Sobhgol Author-X-Name-Last: Gholipour Author-Name: Farhad Salehian Author-X-Name-First: Farhad Author-X-Name-Last: Salehian Author-Name: Hassan Lamouchi Author-X-Name-First: Hassan Author-X-Name-Last: Lamouchi Author-Name: Hassan Mina Author-X-Name-First: Hassan Author-X-Name-Last: Mina Title: A green closed-loop supply chain network: a bi-objective mixed integer linear programming model Abstract: The increasing level of customer awareness and application of environmental laws by governments, on the one hand, and the increasing number of competitors, on the other hand, has obliged industry owners to include green activities in the design of the supply chain network. Green activities include any type of action that reduces environmental degradation. Hence, this study seeks to develop a bi-objective, mixed integer linear programming (MILP) model for designing a green supply chain network. In the proposed model, the minimisation of costs and detrimental environmental effects are discussed. LP metric method is used to solve the bi-objective model and the proposed model is run by using simulated data in small and medium sizes in GAMS software. Finally, the model sensitivity analysis is measured in order to evaluate the validity and performance of the proposed model by using demand-driven scenarios. The results of this model indicate the effectiveness of the proposed model. Journal: Int. J. of Operational Research Pages: 492-513 Issue: 4 Volume: 41 Year: 2021 Keywords: closed-loop supply chain network; CLSCN; mathematical model; green supply chain management. File-URL: http://www.inderscience.com/link.php?id=117078 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:4:p:492-513 Template-Type: ReDIF-Article 1.0 Author-Name: Gopal K. Gupta Author-X-Name-First: Gopal K. Author-X-Name-Last: Gupta Author-Name: A. Banerjee Author-X-Name-First: A. Author-X-Name-Last: Banerjee Title: Analysis of infinite buffer general bulk service queue with state dependent balking Abstract: This paper investigates the effect of impatient phenomena of the arriving customers in a bulk service queue, where inputs are flowing into the system according to the Poisson process and are served in groups according to the 'general bulk service' (GBS) rule. The service time of a group of customers follows exponential distribution. On arrival, a customer decides whether to join or balk the system, based on the observation of the system size and status of the server, i.e., whether server is busy or idle. The steady state joint probability distribution of the number of customers in the queue as well as with the server is obtained by using the probability generating function method, which is based on the roots of the characteristic equations formed using probability generating function for steady state joint probabilities. Finally, various performance measures, such as, average queue length, average waiting time, probability that the server is busy, average queue length when server is busy, etc., have been obtained. The paper ends with several numerical discussions to demonstrate the effect of certain model parameters on the key performance measures. Journal: Int. J. of Operational Research Pages: 137-161 Issue: 2 Volume: 40 Year: 2021 Keywords: balking; general bulk service rule; joint probability distribution; probability generating function; poison queue. File-URL: http://www.inderscience.com/link.php?id=113500 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:2:p:137-161 Template-Type: ReDIF-Article 1.0 Author-Name: Mohamed Amine Abdeljaoued Author-X-Name-First: Mohamed Amine Author-X-Name-Last: Abdeljaoued Author-Name: Zied Bahroun Author-X-Name-First: Zied Author-X-Name-Last: Bahroun Author-Name: Nour El Houda Saadani Author-X-Name-First: Nour El Houda Author-X-Name-Last: Saadani Title: Short-term operating room scheduling: a parallel machine under resource constraints problem Abstract: The paper tackles the daily scheduling of surgical operations in an operating theatre. The considered operating rooms are identical and the set of operations is subdivided into groups, each of them performed by a single surgeon. The objective is to minimise the ending time of the last completed operation (makespan). The problem is NP-hard and is part of the parallel machine scheduling under resource constraints. We provide two mathematical models and compare their performance. The first is based on parallel machines scheduling, while the second highlights the similarities with the strip packing problem. Two heuristics based on a dichotomic approach are then introduced. An experimental study comparing their results to optimal solutions, lower bounds and an existing heuristic from the literature shows that the second proposed method performs the best and provides near-optimal or good results for realistic-size instances in reasonable computational times. Journal: Int. J. of Operational Research Pages: 162-184 Issue: 2 Volume: 40 Year: 2021 Keywords: scheduling; operating room; parallel machines; strip-packing; resource. File-URL: http://www.inderscience.com/link.php?id=113501 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:2:p:162-184 Template-Type: ReDIF-Article 1.0 Author-Name: Mohamed Abd Allah El-Hadidy Author-X-Name-First: Mohamed Abd Allah Author-X-Name-Last: El-Hadidy Title: Spiral with line segment directory for a helix search path to find a randomly located target in the space Abstract: In this paper we present more interesting search plan in the space to find a lost hanging black box in the water from a view point of computational stochastic geometry. The space is divided into cubic cells with knowing side length. There exist one searcher moves on helix path along spiral with line segment directory. Depending on the target has known trivariate known distribution, we focus on the optimal geometry features such as curvature and torsion of the helix search path which minimise the expected value of detecting the target. Assuming trivariate standard normal distribution we present numerical example to show the applicability of this model. Journal: Int. J. of Operational Research Pages: 185-199 Issue: 2 Volume: 40 Year: 2021 Keywords: computational stochastic geometry; search theory; trivariate standard normal distribution. File-URL: http://www.inderscience.com/link.php?id=113502 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:2:p:185-199 Template-Type: ReDIF-Article 1.0 Author-Name: Rajan Gupta Author-X-Name-First: Rajan Author-X-Name-Last: Gupta Author-Name: Sunil K. Muttoo Author-X-Name-First: Sunil K. Author-X-Name-Last: Muttoo Author-Name: Saibal K. Pal Author-X-Name-First: Saibal K. Author-X-Name-Last: Pal Title: A comprehensive review of approaches used for solving tele-centre location allocation problem in geographical plane Abstract: Setup of tele-centre is the worldwide approach for the establishment of information and communication technology infrastructure in rural areas for the overall development of a country. It is a key resource under e-governance plan in any country, but a major problem with their location allocation is the sustainability. Tele-centre establishment require a suitable location to increase the beneficial effect to service seekers. In this research, multi-faceted problems faced by tele-centres are highlighted. This paper presents a comprehensive study on tele-centre's location allocation problem and all the recent development in multi-facility location problem research area through more than 150 research papers from high ranked peer-reviewed journals. The research survey examines all the important parameters for the facility location problem and an objective function is also formulated for the same. Based on the survey literature, it is found that the new allocation methods based on meta-heuristic algorithms are emerging. This study would be a useful contribution in the field of location science, tele-centre location allocation and application of meta-heuristic algorithms in e-governance. Journal: Int. J. of Operational Research Pages: 200-238 Issue: 2 Volume: 40 Year: 2021 Keywords: tele-centres; location allocation; common service centres; CSCs; rural kiosks; meta-heuristic algorithms; e-governance; geographical plane; ICT for rural region. File-URL: http://www.inderscience.com/link.php?id=113503 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:2:p:200-238 Template-Type: ReDIF-Article 1.0 Author-Name: Malla Reddy Perati Author-X-Name-First: Malla Reddy Author-X-Name-Last: Perati Author-Name: Ravi Kumar Gudimalla Author-X-Name-First: Ravi Kumar Author-X-Name-Last: Gudimalla Title: Performance analysis of asynchronous priority-based internet router under self-similar traffic input - queueing system with Markovian input and hyper-exponential services Abstract: In this paper, queueing behaviour of asynchronous priority-based internet router with self-similar traffic input is analysed. As Markov modulated Poisson process (MMPP) emulates self-similar traffic, it is used as input process of pertinent queueing system. For quality of service (QoS) guarantee in a broadband integrated services digital network (B-ISDN), partial buffer sharing (PBS) mechanism is promising one. Since, network traffic is asynchronous and of variable packet lengths, wavelength division multiplexing (WDM) technology is to be employed, according to which, each output port is modelled as multi server queueing system. The service times (packet lengths) are assumed to follow hyper-exponential (Hk) distribution. For the said reasons, router here is modelled as MMPP/Hk/s/C queueing system employing PBS mechanism. High and low priority packet loss probabilities, and mean lengths of non-critical and critical periods are computed, and presented graphically. This analysis is useful in dimensioning the priority-based asynchronous router with self-similar traffic input. Journal: Int. J. of Operational Research Pages: 239-260 Issue: 2 Volume: 40 Year: 2021 Keywords: internet router; self-similarity; priority packets; partial buffer sharing; multi server queue; hyper-exponential distribution; critical period; non-critical period; loss probability. File-URL: http://www.inderscience.com/link.php?id=113504 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:2:p:239-260 Template-Type: ReDIF-Article 1.0 Author-Name: Moustapha Diaby Author-X-Name-First: Moustapha Author-X-Name-Last: Diaby Author-Name: Mark H. Karwan Author-X-Name-First: Mark H. Author-X-Name-Last: Karwan Author-Name: Lei Sun Author-X-Name-First: Lei Author-X-Name-Last: Sun Title: On modelling hard combinatorial optimisation problems as linear programs: refutations of the 'unconditional impossibility' claims Abstract: There has been a series of developments in the recent literature (by essentially a same 'circle' of authors) with the absolute/unconditioned (implicit or explicit) claim that there exists no abstraction of an <i>NP-complete</i> combinatorial optimisation problem in which the defining combinatorial configurations [such as 'tours' in the case of the travelling salesman problem (TSP) for example] can be modelled by a <i>polynomial-sized</i> system of linear constraints. The purpose of this paper is to provide general as well as specific refutations for these recent claims. Journal: Int. J. of Operational Research Pages: 261-278 Issue: 2 Volume: 40 Year: 2021 Keywords: linear programming; combinatorial optimisation; computational complexity; travelling salesman problem; TSP; P vs. NP. File-URL: http://www.inderscience.com/link.php?id=113505 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:2:p:261-278 Template-Type: ReDIF-Article 1.0 Author-Name: Iñigo L. Ansorena Author-X-Name-First: Iñigo L. Author-X-Name-Last: Ansorena Title: On the scheduling of handling equipment in automated container terminals Abstract: This paper deals with the application of the flow shop scheduling problem (FSSP) to automated container terminals. After the description of operations between the quay line and the storage yard we analyse the flow of containers through six well established heuristic methods. Additionally, we apply a full enumeration mechanism to solve the FSSP. This technique enumerates all permutation schedules and picks the best one based on the specified criterion. A numerical illustration is given to clarify the application of FSSP techniques to container terminals. The paper suggests that the selection of the best heuristic is crucial to increase productivity and achieve goals, since it allows time savings around 20%-30% depending on the method used. Journal: Int. J. of Operational Research Pages: 277-291 Issue: 3 Volume: 42 Year: 2021 Keywords: flow shop; sequencing problem; container terminals; heuristic method; automation; guided vehicles; stacking cranes; quay cranes; operation time; time savings. File-URL: http://www.inderscience.com/link.php?id=119406 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:3:p:277-291 Template-Type: ReDIF-Article 1.0 Author-Name: Anna Kalioropoulou Author-X-Name-First: Anna Author-X-Name-Last: Kalioropoulou Author-Name: Basil Manos Author-X-Name-First: Basil Author-X-Name-Last: Manos Author-Name: Thomas Bournaris Author-X-Name-First: Thomas Author-X-Name-Last: Bournaris Title: A DEA model towards efficiency estimation of biomass energy production of agro-energy districts Abstract: In this work, the data envelopment analysis (DEA) is applied for the estimation of relative efficiency in biomass energy production and for optimal organisation of farm planning in accordance to EU goals for renewable energy sources. Specifically, a DEA model with five inputs and one output was employed at the seven prefectures of Northern Greece. The inputs used for the purpose of this study are the main factors of agricultural production, i.e., the land available, the variable costs, the available tractors, the fertilisers and the labour used. The output is the electric energy from the biomass of crop residues and it is consistent with EU objectives for renewable energy sources. The application of the DEA model revealed four prefectures as relatively inefficient and three as relatively efficient. From the empirical analysis, a reorganisation and a better allocation of inputs for the inefficient prefectures is suggested. Journal: Int. J. of Operational Research Pages: 292-309 Issue: 3 Volume: 42 Year: 2021 Keywords: relative efficiency; data envelopment analysis; DEA; biomass energy. File-URL: http://www.inderscience.com/link.php?id=119407 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:3:p:292-309 Template-Type: ReDIF-Article 1.0 Author-Name: Pramoda Kumar Behera Author-X-Name-First: Pramoda Kumar Author-X-Name-Last: Behera Author-Name: Saroj Kumar Padhan Author-X-Name-First: Saroj Kumar Author-X-Name-Last: Padhan Author-Name: Chandal Nahak Author-X-Name-First: Chandal Author-X-Name-Last: Nahak Title: Duality of control problems in general Banach spaces Abstract: Control problems have been given a special attention to the theory of optimisation, which is concerned with problems involving infinite dimensional cases. Control problems along with various types of their duals are described in general Banach spaces. Under convexity assumptions on functionals, several duality (weak, strong and converse) results are established between control primal and the corresponding Mangasarian type dual problem. Again, the Mond-Weir type duality model is constructed to weaken the convexity condition to pseudo-convexity and quasi-convexity. Many nontrivial examples are given to support the efficacy of the new findings. It is found that some of earlier results are the special cases of the present investigations. Journal: Int. J. of Operational Research Pages: 358-370 Issue: 3 Volume: 42 Year: 2021 Keywords: control problems? convexity? Mangasarian type duality? Mond-Weir type duality. File-URL: http://www.inderscience.com/link.php?id=119408 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:3:p:358-370 Template-Type: ReDIF-Article 1.0 Author-Name: G. Ayyappan Author-X-Name-First: G. Author-X-Name-Last: Ayyappan Author-Name: R. Gowthami Author-X-Name-First: R. Author-X-Name-Last: Gowthami Title: Analysis of MAP/PH/1 retrial queue with constant retrial rate, working vacations, abandonment, flush out, search of customers, breakdown and repair Abstract: A retrial queueing model in which the inter arrival times follow Markovian arrival process (MAP), the service times follow phase type distribution and the remaining random variables follow exponential distribution is studied in this paper. We use the matrix analytic method to study the resulting GI/M/1-type queueing model in the steady state. Some performance measures are enumerated. The analysis of the model has been done numerically and graphically. Journal: Int. J. of Operational Research Pages: 310-331 Issue: 3 Volume: 42 Year: 2021 Keywords: Markovian arrival process? MAP? phase type distribution? retrial queues? orbital search? working vacation? breakdown and repair. File-URL: http://www.inderscience.com/link.php?id=119409 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:3:p:310-331 Template-Type: ReDIF-Article 1.0 Author-Name: Suna Cinar Author-X-Name-First: Suna Author-X-Name-Last: Cinar Author-Name: Ferenc Szidarovszky Author-X-Name-First: Ferenc Author-X-Name-Last: Szidarovszky Author-Name: Mehmet Bayram Yildirim Author-X-Name-First: Mehmet Bayram Author-X-Name-Last: Yildirim Title: Enhancing reliability/availability in asset management with retrofitting: a wind turbine case study Abstract: In this study, a mixed-integer linear programming (MILP) modelling approach is proposed to identify the optimum maintenance or retrofitting schedule under budget and energy production constraint(s) by improving failure rate of assets. The proposed reliability/availability asset management with retrofitting (RAAMWR) model seeks to maximise the total net profit subject to achieving a target reliability/availability value and minimise the total improvement cost subject to a budgetary constraint. We apply our model to a case study involving wind turbines (WTs). The results of this study show that to reach the target reliability value with improved failure rate data, model selects retrofitting due to lower loss time and high energy production rate of retrofitting options. This optimal retrofitting choice is not only due to low loss time, but also improving the existing failure rate of an asset to reach the target reliability. In addition, the effects of key parameters on total cost, such as operation and maintenance (O%M) cost, retrofitting cost, budget allocated for retrofitting, and different target reliability values on the optimal improvement policy were considered. Journal: Int. J. of Operational Research Pages: 400-421 Issue: 3 Volume: 42 Year: 2021 Keywords: mixed-integer linear programming; MILP; wind turbine; reliability; asset management; availability; retrofitting; optimisation. File-URL: http://www.inderscience.com/link.php?id=119410 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:3:p:400-421 Template-Type: ReDIF-Article 1.0 Author-Name: G. Ayyappan Author-X-Name-First: G. Author-X-Name-Last: Ayyappan Author-Name: M. Nirmala Author-X-Name-First: M. Author-X-Name-Last: Nirmala Title: Analysis of unreliable bulk queueing system with overloading service, variant arrival rate, closedown under multiple vacation policy Abstract: In this article, an unreliable single server bulk queueing model with overloading service, variant arrival rate, closedown under multiple vacations are considered. The arrival rates of the units are different and depends upon the server status. On service completion epoch, if the queue length is less than '<i>a</i>' then the server perform closedown work. Following the closedown, the server leaves for multiple vacations of random length. We incorporated the overloading concept for the server which is assured in various practical applications. When the server is in working modes, breakdown may occur randomly at any instant during essential/overloading service. The repair job of broken down machine is done immediately and the server returns to render its remaining service. We derived the probability distribution of queue length at a departure and random epoch using supplementary variable technique. Various performance indices namely the expected length of the queue; the expected waiting time in the queue are obtained. Stability condition and steady-state probabilities are also established. In order to match our investigation with the earlier existing results, we discuss some particular cases. Finally, numerical illustration along with graphical studies are presented to visualise the effect of the parameters of the system. Journal: Int. J. of Operational Research Pages: 371-399 Issue: 3 Volume: 42 Year: 2021 Keywords: general bulk service? overloading service? breakdown and repair? closedown? multiple vacations? variant arrival rate. File-URL: http://www.inderscience.com/link.php?id=119416 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:3:p:371-399 Template-Type: ReDIF-Article 1.0 Author-Name: Mubashir Hayat Author-X-Name-First: Mubashir Author-X-Name-Last: Hayat Title: An economic production quantity model with imperfection in process, unit transportation cost and backordering Abstract: Determining batch quantity for manufacturer in an imperfect production setup is a key issue during the last decade. Several mathematical models have been developed for this purpose but these models are lacking of the consideration of unit transportation cost in the system-wide cost. It is quite clear, that nowadays the transportation accounts for a huge portion of the overall cost of a product. Therefore, there is a need to involve transportation cost into the model for better decision-making process. In this way, the paper incorporates unit transportation cost in an imperfect environment and allowing backorders as well as random defects. Three cases have been modelled by assuming the defective rate following uniform, triangular and beta distribution. Sensitivity analysis has been carried out to point out the important specification of all the three cases of the model. Journal: Int. J. of Operational Research Pages: 279-296 Issue: 3 Volume: 40 Year: 2021 Keywords: EPQ model; unit transportation cost; imperfection in process; backordering. File-URL: http://www.inderscience.com/link.php?id=114300 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:3:p:279-296 Template-Type: ReDIF-Article 1.0 Author-Name: Mohammad Reza Hassanzadeh Author-X-Name-First: Mohammad Reza Author-X-Name-Last: Hassanzadeh Author-Name: Changiz Valmohammadi Author-X-Name-First: Changiz Author-X-Name-Last: Valmohammadi Title: Evaluation and ranking of the banks and financial institutes using fuzzy AHP and TOPSIS techniques Abstract: The main purpose of this is to evaluate and rank the credit/financial institutes of Tehran stock market. The criteria were determined based on prior research and securities stock market literature and also based on the factors taken into account in stock selection. After screening the criteria and through holding interview with experts, eight criteria were finally chosen. Using fuzzy analytic hierarchical analysis (FAHP), relative weights were calculated for each criterion and ultimately based on these weights, banks were ranked using technique for order preference by similarity to an ideal solution method (TOPSIS). The results revealed that Bank Pasargad, Karafarin Bank and Day Bank ranked first, second, and third respectively. The obtained results could serve as guidance for investors from one hand and the owners of the survey institutions and banks on the other hand to take necessary measures in accomplishing their objectives. This evaluation and ranking model has significant applied potentials in shares investment of a company among other similar companies in the context of Iran. Journal: Int. J. of Operational Research Pages: 297-317 Issue: 3 Volume: 40 Year: 2021 Keywords: securities stock; ranking; multiple criteria decision making; MCDM; fuzzy analytic hierarchical process; FAHP; TOPSIS; Iran. File-URL: http://www.inderscience.com/link.php?id=114301 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:3:p:297-317 Template-Type: ReDIF-Article 1.0 Author-Name: Suna Cinar Author-X-Name-First: Suna Author-X-Name-Last: Cinar Author-Name: Saeed Rubaiee Author-X-Name-First: Saeed Author-X-Name-Last: Rubaiee Author-Name: Mehmet Bayram Yildirim Author-X-Name-First: Mehmet Bayram Author-X-Name-Last: Yildirim Title: Asset management strategies for wind turbines: keeping or retrofitting existing wind turbines? Abstract: In this study, a parallel replacement problem with retrofitting (PRP-R) model is proposed to determine the trade-off between retrofitting and replacing an asset. The primary objective is to identify the replacement, maintenance and retrofitting schedule that optimise purchasing new assets, operation and maintenance (O%M) cost, and retrofitting cost under budget and production constraints resulting in a mixed-integer linear programming formulation. This model is applied to a case study of energy industry involving wind turbines (WTs). Results show that due to a lower O%M cost, retrofitting is less costly than keeping the WTs. In addition, the effects of key parameters such as O%M cost, retrofitting cost, budget allocated for retrofitting and governmental subsidy on the optimal replacement policy on total cost are studied. This research contributes a model that can be used to determine if WT retrofitting is economically justified and provides a rigorous analytical framework for optimising the decision-making process over the wind farm life cycle. Journal: Int. J. of Operational Research Pages: 318-341 Issue: 3 Volume: 40 Year: 2021 Keywords: wind turbine; mixed-integer linear programming; asset management; retrofitting; optimisation. File-URL: http://www.inderscience.com/link.php?id=114302 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:3:p:318-341 Template-Type: ReDIF-Article 1.0 Author-Name: Javad Zarei Author-X-Name-First: Javad Author-X-Name-Last: Zarei Author-Name: Morteza Rasti-Barzoki Author-X-Name-First: Morteza Author-X-Name-Last: Rasti-Barzoki Author-Name: Seyed Reza Hejazi Author-X-Name-First: Seyed Reza Author-X-Name-Last: Hejazi Title: A game theoretic approach for integrated pricing, lot-sizing and advertising decisions in a dual-channel supply chain Abstract: This paper discusses the coordination of pricing, lot-sizing and advertising policies in a dual-channel supply chain including one manufacturer and one retailer. The manufacturer produces one type of product and sells it to the retailer at wholesale price and also directly to consumers through direct channel. Consumers buy the product at retail price from the retailer and with direct sale price from the manufacturer. Demand depends on price and advertising efforts. Relationship between the manufacturer and the retailer has been modelled by two non-cooperative games of Nash and Stackelberg-retailer and one cooperative game. Finally, the change effect of the important parameters on the profit functions and the decision variables has been investigated. The results show that with increasing the cross-price sensitivity, the manufacturer's equilibrium profit for the two non-cooperative games increases. However, the increase in this parameter has no effect on the retailer's equilibrium profit. Journal: Int. J. of Operational Research Pages: 342-365 Issue: 3 Volume: 40 Year: 2021 Keywords: supply chain; pricing; lot-sizing; advertising; game theory. File-URL: http://www.inderscience.com/link.php?id=114303 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:3:p:342-365 Template-Type: ReDIF-Article 1.0 Author-Name: Kamal Sanguri Author-X-Name-First: Kamal Author-X-Name-Last: Sanguri Author-Name: Sri Vanamalla Venkataraman Author-X-Name-First: Sri Vanamalla Author-X-Name-Last: Venkataraman Title: Inventory model based upon order criticality Abstract: For a typical distribution network, we can segregate the demand at the central demand catering centre as critical if the order is triggered by a direct customer requirement and non-critical if the replenishment order is triggered for routine stocking purpose by the customer touch point. In the traditional model discussed in literature the segregation is based upon the use based criterion, with the objective of keeping the cost of ordering, shortages and inventory at a minimum level. Through this research we propose a modification of the traditional model by incorporating different classes of demand based upon their criticality while maintaining appropriate service levels to them. Journal: Int. J. of Operational Research Pages: 380-409 Issue: 3 Volume: 40 Year: 2021 Keywords: inventory management; rationing; service level; critical level. File-URL: http://www.inderscience.com/link.php?id=114304 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:3:p:380-409 Template-Type: ReDIF-Article 1.0 Author-Name: Fabian G. Beck Author-X-Name-First: Fabian G. Author-X-Name-Last: Beck Author-Name: Christoph H. Glock Author-X-Name-First: Christoph H. Author-X-Name-Last: Glock Title: A dynamic programming approach for solving the economic lot scheduling problem with batch shipments Abstract: This note investigates the economic lot scheduling problem (ELSP) with batch shipments. It first modifies an existing formulation of the ELSP to account both for the cases of equal-sized and geometrically increasing batch shipments, and it then adapts the popular dynamic programming approach of Bomberger to the new planning situation. In addition, the paper specifies some steps of Bomberger's solution procedure that had been formulated imprecisely in the original publication of the author. The paper compares the solution approach proposed in this note to the popular methods of Hanssmann as well as Haessler and Hogue in a numerical experiment and highlights the influence of the batch shipments on the relative performance of the solution procedures. Our results show that the proposed modification reduces the performance disadvantage of Bomberger's basic period approach, which may be interesting especially for practitioners that are interested in an easy-to-apply procedure for solving the ELSP in practice. Our changes to Bomberger's solution procedure support finding the lowest total cost solution that had not always been obtained in earlier publications. Journal: Int. J. of Operational Research Pages: 366-379 Issue: 3 Volume: 40 Year: 2021 Keywords: economic lot scheduling problem; ELSP; Bomberger's method; basic period approach; BPA; batch shipments; dynamic programming. File-URL: http://www.inderscience.com/link.php?id=114305 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:3:p:366-379 Template-Type: ReDIF-Article 1.0 Author-Name: Hamid Reza Golmakani Author-X-Name-First: Hamid Reza Author-X-Name-Last: Golmakani Author-Name: Mahtab Eskandar Author-X-Name-First: Mahtab Author-X-Name-Last: Eskandar Title: Non-dominated sorting genetic algorithm-II for locating emergency bases to minimise mean and standard deviation of service time Abstract: Pre-hospital emergency is one of the most important issues in healthcare systems. One of the items that strongly influence the performance of emergency services is the location of emergency bases since the service time plays a key role in the success of an emergency mission. In this paper, a binary nonlinear programming model is proposed for locating emergency bases. The goal is to minimise the mean and standard deviation of emergency service time while satisfying the relevant constraints. To cope with the computational complexity in obtaining optimal solutions, non-dominated sorting genetic algorithm (NSGA-II) is proposed. The proposed NSGA-II approach is applied for locating emergency bases in a part of Tehran metropolis and non-dominated solutions are presented. Sensitivity analysis on the available budget is also presented. Journal: Int. J. of Operational Research Pages: 332-357 Issue: 3 Volume: 42 Year: 2021 Keywords: pre-hospital emergency; nonlinear integer programming; emergency bases locating; Bi-objective functions; service time. File-URL: http://www.inderscience.com/link.php?id=119430 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:3:p:332-357 Template-Type: ReDIF-Article 1.0 Author-Name: M. Mathirajan Author-X-Name-First: M. Author-X-Name-Last: Mathirajan Author-Name: P. Suba Author-X-Name-First: P. Author-X-Name-Last: Suba Author-Name: Ramakrishnan Ramanathan Author-X-Name-First: Ramakrishnan Author-X-Name-Last: Ramanathan Title: Location of depots and allocation of buses to depots in urban road transport organisations: a mathematical model and greedy heuristic algorithm Abstract: Optimising the cost of operations is one of the major issues in any urban road transport organisations (URTOs). In this study, a decision problem on location of depots (adding new locations and removing existing ones) and allocation of buses to depots is considered, as observed in one of the major URTOs in India. The main focus of this research is to provide analytic methods to minimise the cost of operations comprising: 1) dead-kilometre cost; 2) fixed cost associated with introducing new depots; 3) salvage value due to closing the depots. To do so, a (0-1) mixed integer linear programming (MILP) model is proposed and its workability is demonstrated. In addition, a simple greedy heuristic algorithm is also proposed. A computational experiment is developed to understand the performance efficiency of the proposed greedy heuristic algorithm in comparison with the optimal solution. From the average and worst case analyses of the performance evaluation, it is observed that the proposed greedy heuristic algorithm provides near-optimal solution. The (0-1) MILP model and the efficient greedy heuristic algorithm proposed in this study can be used to help make better decisions on location of depots and allocation of buses to depots of URTOs in general. Journal: Int. J. of Operational Research Pages: 411-436 Issue: 4 Volume: 40 Year: 2021 Keywords: location of depots; allocation of buses to depots; dead-kilometre costs; salvage value; MILP model; greedy heuristic algorithm. File-URL: http://www.inderscience.com/link.php?id=114835 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:4:p:411-436 Template-Type: ReDIF-Article 1.0 Author-Name: Carlos Campos Amezcua Author-X-Name-First: Carlos Campos Author-X-Name-Last: Amezcua Author-Name: Omar G. Rojas Author-X-Name-First: Omar G. Author-X-Name-Last: Rojas Author-Name: Emilio Zamudio Gutierrez Author-X-Name-First: Emilio Zamudio Author-X-Name-Last: Gutierrez Author-Name: Elias Olivares-Benitez Author-X-Name-First: Elias Author-X-Name-Last: Olivares-Benitez Title: Flexible shift scheduling for a call centre using column generation Abstract: A shift scheduling problem for a call centre is solved by applying a column generation method. The objective is to find an employee schedule within the planning horizon that meets staffing requirements provided by the customer and that minimises the costs of excess-staffing and under-staffing. To solve the problem, two iterative models were used: the first being a mixed integer-linear programming model, the master problem, and the second being a column generation model. In a first approach, the master problem was solved considering a fixed number of shift patterns. The second approach was to use both models iteratively to generate shift patterns to be used in the master problem. Both approaches met all constraints relatively fast, but the column generation model decreased the cost considerably when cheaper shift patterns were generated. The models contribute to the current literature by providing flexibility to consider under-coverage and over-coverage at two levels. Journal: Int. J. of Operational Research Pages: 502-523 Issue: 4 Volume: 40 Year: 2021 Keywords: shift scheduling; call centre; staffing; mixed integer linear programming; master problem; column generation; shift pattern; flexibility. File-URL: http://www.inderscience.com/link.php?id=114836 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:4:p:502-523 Template-Type: ReDIF-Article 1.0 Author-Name: Nura Khalil Author-X-Name-First: Nura Author-X-Name-Last: Khalil Author-Name: Ibrahim Yusuf Author-X-Name-First: Ibrahim Author-X-Name-Last: Yusuf Title: Reliability models of a series-parallel system with replacement at failure Abstract: The paper deals with the availability analysis of a series-parallel system consisting of four subsystems: A<SUB align="right"><SMALL>11</SMALL></SUB>, B, C and A<SUB align="right"><SMALL>12</SMALL></SUB>. Subsystem B contains units' b<SUB align="right"><SMALL>11</SMALL></SUB> and b<SUB align="right"><SMALL>12</SMALL></SUB> arranged in active parallel, subsystem C contains units' c<SUB align="right"><SMALL>11</SMALL></SUB> and g<SUB align="right"><SMALL>12</SMALL></SUB> arranged in active parallel. The system is exposed to two types of failure. Type I failure is a unit failure called partial failure where the failed unit is replaced with new and identical one while type II is a common cause failure to either subsystem B or C in which the failed subsystem is replaced with new one. Two probabilistic models are discussed. In model I (system without common cause failure), the system has type I failure while in model II (system with common cause failure) the system has both type I and II failure. In both models, the system has three modes: full capacity, reduced capacity and failure mode. Failure and replacement rate were assumed to be exponentially distributed. Through the transition diagram, system of first order linear differential equations were developed and solved to obtain the explicit expressions for steady-state availability. At last, some numerical examples have been taken to clarify the results. Journal: Int. J. of Operational Research Pages: 524-543 Issue: 4 Volume: 40 Year: 2021 Keywords: availability; series-parallel; common cause failure; partial failure. File-URL: http://www.inderscience.com/link.php?id=114837 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:4:p:524-543 Template-Type: ReDIF-Article 1.0 Author-Name: Xiangling Hu Author-X-Name-First: Xiangling Author-X-Name-Last: Hu Author-Name: Jaideep Motwani Author-X-Name-First: Jaideep Author-X-Name-Last: Motwani Title: The second purchase decision under selling price-sensitive stochastic demand and purchasing price uncertainty Abstract: It is quite common for a retailer to stock a specific quantity of a product more than once during a certain time period and then sell the product to the customers during the selling season. The retailer also has the option to make a second purchase, as long as there is a potential profit increase on account of the purchase. Due to the stochastic spot market purchasing price and the selling price dependent random demand, the retailer needs to determine whether a second purchase is necessary and if so what are the corresponding order time, quantity, and selling price in order to maximise the expected profit. In this paper, we develop a reality-adaptable solution algorithm to simplify the solution procedure. We also run simulations to analyse the inventory decisions, and to compute the profits when a second purchase is possible. Journal: Int. J. of Operational Research Pages: 489-501 Issue: 4 Volume: 40 Year: 2021 Keywords: purchasing; pricing; price uncertainties; price-sensitive stochastic demand. File-URL: http://www.inderscience.com/link.php?id=114838 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:4:p:489-501 Template-Type: ReDIF-Article 1.0 Author-Name: P. Vijaya Laxmi Author-X-Name-First: P. Vijaya Author-X-Name-Last: Laxmi Author-Name: P. Rajesh Author-X-Name-First: P. Author-X-Name-Last: Rajesh Author-Name: T.W. Kassahun Author-X-Name-First: T.W. Author-X-Name-Last: Kassahun Title: Analysis of a variant working vacation queue with customer impatience and server breakdowns Abstract: This paper analyses an infinite buffer single server variant working vacation queueing model in which the arriving customer may balk and the server is subject to breakdown. The service times during regular busy period and working vacation period, vacation times, breakdown times and repair times are assumed to be exponentially distributed and are mutually independent. In working vacation period, the customer may renege due to impatience. We derive the probability generating function of the steady-state probabilities and obtain the closed form expressions of the system size. In addition, we obtain some performance measures and a total expected profit function per unit time is designed to determine the optimal values at the maximum profit. We employ the particle swarm optimisation method to solve the profit optimisation problem. Journal: Int. J. of Operational Research Pages: 437-459 Issue: 4 Volume: 40 Year: 2021 Keywords: queue; balking; reneging; variant working vacations; server breakdowns; particle swarm optimisation; PSO. File-URL: http://www.inderscience.com/link.php?id=114839 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:4:p:437-459 Template-Type: ReDIF-Article 1.0 Author-Name: Mohamed Dia Author-X-Name-First: Mohamed Author-X-Name-Last: Dia Author-Name: Pawoumodom M. Takouda Author-X-Name-First: Pawoumodom M. Author-X-Name-Last: Takouda Author-Name: Amirmohsen Golmohammadi Author-X-Name-First: Amirmohsen Author-X-Name-Last: Golmohammadi Title: Efficiency measurement of Canadian oil and gas companies Abstract: In this study, we perform an efficiency analysis of Canadian oil and gas firms. Using data envelopment analysis, technical, managerial and scale scores from ten samples built from 110 oil and gas companies, listed in Canadian stock exchanges, are computed for the years 2012, 2013, 2014, and 2015. Our analysis, supported by appropriate statistical tests, confirms that the Canadian oil and gas industry exhibited predominantly low overall technical efficiency levels both for each of the years and overall for the four years. We have observed that the main source of inefficiencies was the management of operations. In addition, we have seen consistently that across the samples, a statistically significant relationship exists between the efficiency scores and the size of the companies. Finally, we have observed the existence of a relationship between the efficiency scores and the type of producer (pure oil vs. oil and gas), but we could not reach conclusions on the best performer that was consistent across the samples. Journal: Int. J. of Operational Research Pages: 460-488 Issue: 4 Volume: 40 Year: 2021 Keywords: data envelopment analysis; DEA; efficiency; oil and gas companies; Canada. File-URL: http://www.inderscience.com/link.php?id=114840 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:40:y:2021:i:4:p:460-488 Template-Type: ReDIF-Article 1.0 Author-Name: Bing-Hai Zhou Author-X-Name-First: Bing-Hai Author-X-Name-Last: Zhou Author-Name: Jiaying Gu Author-X-Name-First: Jiaying Author-X-Name-Last: Gu Title: Energy-awareness scheduling of unrelated parallel machine scheduling problems with multiple resource constraints Abstract: The environmental and economic pressures caused by energy consumption arouse energy-saving consciousness of the manufacturing industry. To this end, the paper integrates energy-awareness into the research of the unrelated parallel machines scheduling problem with multiple auxiliary resources which is typical in the photolithography process of wafer fabrication. With a comprehensive consideration of jobs requiring different processing demands, setup times, different ready times, resource constraints and energy consumption, a scheduling model with a multi-objective function of minimising the total weighted completion time and total energy consumption of the system is developed. On the basis of the model, a modified multi-objective artificial immune algorithm integrated with non-domination sorting strategy is put forward to crack the problem. Furthermore, in order to improve the performance of the proposed algorithm, clone operators, neighbourhood search operators, elite-preservation operators are applied to the algorithm. Finally, the experimental results and analysis validate that the presented algorithm is efficient and effective. Journal: Int. J. of Operational Research Pages: 196-217 Issue: 2 Volume: 41 Year: 2021 Keywords: multi-objective; artificial immune algorithm; energy consumption; resource constraints. File-URL: http://www.inderscience.com/link.php?id=115623 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:2:p:196-217 Template-Type: ReDIF-Article 1.0 Author-Name: Yertai Tanai Author-X-Name-First: Yertai Author-X-Name-Last: Tanai Author-Name: Emmanuel Dechenaux Author-X-Name-First: Emmanuel Author-X-Name-Last: Dechenaux Author-Name: Eddy B. Patuwo Author-X-Name-First: Eddy B. Author-X-Name-Last: Patuwo Author-Name: Alfred L. Guiffrida Author-X-Name-First: Alfred L. Author-X-Name-Last: Guiffrida Title: Bargaining in a closed-loop supply chain with consumer returns Abstract: The increasing quality of consumer returns creates substantial economic potential for closed-loop supply chains to extract value from returned goods. In this paper, we focus on the supply chain interaction between a retailer and a third party reverse logistics provider (3PRLP) to process consumer returns under a full refund policy. In the model, the retailer orders processed returns from the 3PRLP in exchange for a fee and then resell the processed returns. We compare an uncoordinated supply chain, in which the retailer makes a take-it-or-leave it offer of a fee to the 3PRLP, to a coordinated supply chain, in which the retailer and the 3PRLP jointly decide on the quantity of processed returns and the fee using Nash bargaining. We show that coordination leads to both a higher quantity processed and a higher fee than in the uncoordinated case. We also derive a set of sensitivity results with respect to important parameters. Journal: Int. J. of Operational Research Pages: 168-195 Issue: 2 Volume: 41 Year: 2021 Keywords: closed-loop supply chain; CLSC; supply chain coordination; 3PRLP; consumer returns; Nash bargaining. File-URL: http://www.inderscience.com/link.php?id=115624 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:2:p:168-195 Template-Type: ReDIF-Article 1.0 Author-Name: S.K. Yadav Author-X-Name-First: S.K. Author-X-Name-Last: Yadav Author-Name: Dinesh K. Sharma Author-X-Name-First: Dinesh K. Author-X-Name-Last: Sharma Author-Name: S.S. Mishra Author-X-Name-First: S.S. Author-X-Name-Last: Mishra Title: New modified ratio type estimator of the population mean using the known median of the study variable Abstract: In this paper, we propose an estimator that utilises the known value of the population median of the study variable under simple random sampling without replacement (SRSWOR). As per requirement and for comparison, we derived the bias and mean squared error (MSE) of the proposed estimator to the first degree of approximation. The optimum values of the characterising constants involved in the proposed estimator were also obtained. The characterising scalar may take different values which results in different values of MSE of proposed estimator; therefore its optimum value was obtained. The least value of MSE of proposed estimator is derived for this optimum value of characterising constant. Efficiency comparison of the proposed estimator has been made with other existing competing estimators of the population mean which makes use of auxiliary information under SRSWOR. Theoretical findings regarding the proposed estimator have been verified through the numerical study. It has been shown through a numerical example that the proposed estimator has the least MSE among other existing competing estimators of the population mean of the study variable. Journal: Int. J. of Operational Research Pages: 151-167 Issue: 2 Volume: 41 Year: 2021 Keywords: population median; auxiliary variable; bias; mean squared error; MSE; relative efficiency. File-URL: http://www.inderscience.com/link.php?id=115625 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:2:p:151-167 Template-Type: ReDIF-Article 1.0 Author-Name: Abdallah W. Aboutahoun Author-X-Name-First: Abdallah W. Author-X-Name-Last: Aboutahoun Author-Name: Fatma El-Safty Author-X-Name-First: Fatma Author-X-Name-Last: El-Safty Title: A linear algorithm for a minimax location of a path-shaped facility with a specific length in a weighted tree network Abstract: This paper considers the problem of locating a path-shaped facility of a specific size on a weighted tree network. The criterion for optimality used in this paper is the minimax criterion in which the weighted distance to the farthest vertex from the facility is minimised. The minimax criterion gives acceptable results from the point of view of the fast response for the clients who are located far away from the facility. This location problem usually has applications in computer science, information science, and operations research. An <i>O</i>(<i>n</i>) time algorithm is proposed for finding the optimal location of a path-shaped facility of a bounded length on a weighted tree network, where <i>n</i> is the number of vertices in the tree. Journal: Int. J. of Operational Research Pages: 218-225 Issue: 2 Volume: 41 Year: 2021 Keywords: tree network; facility location; minimax criterion; central path. File-URL: http://www.inderscience.com/link.php?id=115626 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:2:p:218-225 Template-Type: ReDIF-Article 1.0 Author-Name: Mohammad Izadikhah Author-X-Name-First: Mohammad Author-X-Name-Last: Izadikhah Title: Developing a new chance constrained modified ERM model to measure performance of repair and maintenance groups of IRALCO Abstract: Evaluating the performance of repair and maintenance groups is recognised as a key component of improving on strategic and operational levels. The purpose of this paper is to develop a model to evaluate the maintenance groups of IRALCO. Data envelopment analysis (DEA) is a useful method for measuring performance of repair and maintenance groups. However, in reality there might be problem with the stochastic data. For this purpose, this paper presents a new stochastic modified enhanced Russell measure (ERM) model to measure performance of repair and maintenance groups. An important property of the proposed model is stated and proved as a proposition. A case study demonstrates applicability of our approach. Journal: Int. J. of Operational Research Pages: 226-243 Issue: 2 Volume: 41 Year: 2021 Keywords: data envelopment analysis; DEA; chance-constrained data envelopment analysis; stochastic DEA; efficiency; stochastic data. File-URL: http://www.inderscience.com/link.php?id=115627 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:2:p:226-243 Template-Type: ReDIF-Article 1.0 Author-Name: Jean-Paul Arnaout Author-X-Name-First: Jean-Paul Author-X-Name-Last: Arnaout Title: Worm optimisation algorithm to minimise the makespan for the two-machine scheduling problem with a single server Abstract: This paper considers the problem of scheduling a given set of jobs on two identical parallel machines. Each job must be processed on one of the machines, and prior to processing, the job is set up on its machine using one server; the latter is shared between the two machines. This problem is known as the two-machine scheduling problem with a single server, and our objective is to minimise the makespan. A worm optimisation algorithm (WO) is introduced for this NP-hard problem, and its performance is compared to ant colony optimisation, simulated annealing, and genetic algorithm, as well as exact approach. The superiority of WO over the other algorithms is obtained through extensive computational results. Journal: Int. J. of Operational Research Pages: 270-281 Issue: 2 Volume: 41 Year: 2021 Keywords: worm optimisation; parallel machines; single server. File-URL: http://www.inderscience.com/link.php?id=115628 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:2:p:270-281 Template-Type: ReDIF-Article 1.0 Author-Name: Stella Sofianopoulou Author-X-Name-First: Stella Author-X-Name-Last: Sofianopoulou Author-Name: Ioannis Mitsopoulos Author-X-Name-First: Ioannis Author-X-Name-Last: Mitsopoulos Title: A review and classification of heuristic algorithms for the inventory routing problem Abstract: The inventory routing problem (IRP) is an integration of vehicle routing and inventory management problems. In the recent years, it has increasingly drawn the attention of the researchers because of its potentially significant practical value. The IRP is classified as NP-hard problem since it subsumes the vehicle routing problem (VRP). This fact led to the development of many heuristic or metaheuristic approaches, although a small number of exact methods have been introduced recently. Heuristic methods offer the advantage of shorter time scales, i.e., greater computational efficiency, on the expense of course of the accuracy of the results. The immediate trigger for this study is our concern about results validation, which has been debatable in early papers, and only recently a systematic effort to create a set of optimally solved benchmark instances has been made. This article presents the heuristic methods for solving the basic variants of IRP found in the literature, stressing the computational results and the solution verification approach, rather than the methodology of the algorithms. The paper concludes with a discussion on the quality of the performance assessment of the proposed algorithms. Journal: Int. J. of Operational Research Pages: 282-298 Issue: 2 Volume: 41 Year: 2021 Keywords: heuristic algorithms; literature review; results validation; inventory routing problem; IRP. File-URL: http://www.inderscience.com/link.php?id=115630 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:2:p:282-298 Template-Type: ReDIF-Article 1.0 Author-Name: S. Saravana Kumar Author-X-Name-First: S. Saravana Author-X-Name-Last: Kumar Author-Name: C. Rajendran Author-X-Name-First: C. Author-X-Name-Last: Rajendran Author-Name: Rainer Leisten Author-X-Name-First: Rainer Author-X-Name-Last: Leisten Title: Bounding strategies for obtaining a lower bound for N-job and M-machine flowshop scheduling problem with objective of minimising the total flowtime of jobs Abstract: In this paper, bounding strategies for determining a lower bound on the completion time of a job sequenced in each position in the permutation sequence on each machine in permutation flowshop scheduling problem with minimisation of total flowtime of jobs as objective are discussed. Basically, the bounding strategies are machine-based bounding strategies used for determining the lower bound on total flowtime of jobs for all the small-sized and large-sized benchmark flowshop scheduling problem instances proposed by Vallada et al. (2015). The lower bound matrix can be pruned as tightening constraints into the mixed integer linear programming (MILP) model with objective of minimisation of total flowtime of jobs. Since the flowshop scheduling problem with total flowtime objective is difficult, two kinds of linear programming (LP) relaxation methods are used for determining an LP-based lower bound on total flowtime of jobs for some benchmark problem instances proposed by Vallada et al. (2015). Journal: Int. J. of Operational Research Pages: 244-269 Issue: 2 Volume: 41 Year: 2021 Keywords: scheduling; flowshop; total flowtime of jobs; lower bound. File-URL: http://www.inderscience.com/link.php?id=115634 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:2:p:244-269 Template-Type: ReDIF-Article 1.0 Author-Name: Bin Zhou Author-X-Name-First: Bin Author-X-Name-Last: Zhou Author-Name: Hua Zhong Author-X-Name-First: Hua Author-X-Name-Last: Zhong Author-Name: John Wang Author-X-Name-First: John Author-X-Name-Last: Wang Title: The effect of order incentives in a multi-product dynamic inventory model Abstract: This paper addresses the challenges in a multi-product inventory system with uncertain demands. As an incentive, free shipping is used by the supplier to stimulate large orders from customer, who reviews and restocks inventory periodically. The model is first established through stochastic dynamic programming and the characteristics of the optimal policies are analysed. As the optimal control policies are found very complex, accurate lower bound approximations and effective heuristic policies are proposed and discussed. Finally, performance of the lower bounds and heuristics is evaluated through extensive numerical studies which also evaluate the effects of key system parameters including service levels and varied costs. Journal: Int. J. of Operational Research Pages: 73-90 Issue: 1 Volume: 42 Year: 2021 Keywords: production and inventory management; multiple products; stochastic model; heuristics. File-URL: http://www.inderscience.com/link.php?id=117685 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:1:p:73-90 Template-Type: ReDIF-Article 1.0 Author-Name: Mohamed Abd Allah El-Hadidy Author-X-Name-First: Mohamed Abd Allah Author-X-Name-Last: El-Hadidy Author-Name: Ajab Abdullah Alfreedi Author-X-Name-First: Ajab Abdullah Author-X-Name-Last: Alfreedi Author-Name: Alaa Awad Alzulaibani Author-X-Name-First: Alaa Awad Author-X-Name-Last: Alzulaibani Title: Optimal multiplicative generalised coordinated search technique to find a d-dimensional random walker Abstract: This paper presents a new interesting search model that minimises the expected value of the total detection cost of the d-dimensional random walk target with maximum probability. This technique is called a generalised coordinated linear search technique with multiple searchers. The target may be in one of the d-directions (dimensions) inside the space. We study this technique from a probabilistic and optimisation point of view where each direction is considered as a cylinder and it is searched by two searchers. They start the searching process from any point rather than the origin. The target's initial position is a random variable vector with a known probability distribution. We show the existence of a finite search plan by using the analytical methods. To minimise the expected value of the first meeting time between one of the searchers and the target, we should discuss the existence of the optimality conditions for this search plan and then find the optimal search plan. A numerical example illustrates the effectiveness of this technique. Journal: Int. J. of Operational Research Pages: 1-33 Issue: 1 Volume: 42 Year: 2021 Keywords: coordinated search technique; optimality conditions; d-dimensional random walk target. File-URL: http://www.inderscience.com/link.php?id=117686 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:1:p:1-33 Template-Type: ReDIF-Article 1.0 Author-Name: Anoop N. Nair Author-X-Name-First: Anoop N. Author-X-Name-Last: Nair Author-Name: M.J. Jacob Author-X-Name-First: M.J. Author-X-Name-Last: Jacob Title: Analysis of self service (s, S) inventory with general lead time and positive service time Abstract: This paper deals with the analysis of (<i>s</i>, <i>S</i>) inventory with general lead time and positive service time in a self service environment. The time for serving the inventory is considered as the service time. Both the inter arrival times and service times are assumed to be exponential. Unsatisfied demands are lost. The transient and steady state analysis of such an inventory system are carried out. Explicit expressions for the Laplace transforms of the joint probability distributions of the number of demands and inventory size are obtained using supplementary variable technique. Important system characteristics and numerical results are also presented. Journal: Int. J. of Operational Research Pages: 91-106 Issue: 1 Volume: 42 Year: 2021 Keywords: inventory? (s, S) inventory policy? supplementary variable techniques. File-URL: http://www.inderscience.com/link.php?id=117689 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:1:p:91-106 Template-Type: ReDIF-Article 1.0 Author-Name: Xiaoming Li Author-X-Name-First: Xiaoming Author-X-Name-Last: Li Author-Name: Qidong Cao Author-X-Name-First: Qidong Author-X-Name-Last: Cao Author-Name: Thomas E. Griffin Author-X-Name-First: Thomas E. Author-X-Name-Last: Griffin Title: The effect of supply chain structure on inventory management: serial or parallel? Abstract: While the effect of lead time and its variability on the performance of supply chains continues to attract the attention of academicians and practitioners, the current research has been silent on how a topographic structural change of a supply chain simultaneously reduces both mean and variance of lead time. This study provides such an approach to concurrently reduce both mean and variance of lead time by a simple change on the supply chain structure from serial to parallel. We then show that such lead time reduction reduces mean and variance of lead time demand, which reduce cost in inventory management. We finally illustrate how our approach can be applied to more complex supply chains. Journal: Int. J. of Operational Research Pages: 56-72 Issue: 1 Volume: 42 Year: 2021 Keywords: lead time reduction; inventory management; supply chain management; serial and parallel; structural change. File-URL: http://www.inderscience.com/link.php?id=117690 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:1:p:56-72 Template-Type: ReDIF-Article 1.0 Author-Name: Drinko Kurevija Author-X-Name-First: Drinko Author-X-Name-Last: Kurevija Title: Research and development project funding and the efficiency of participating companies - the case of the Austrian general program Abstract: This article analyses the performances of the Austrian Research Promotion Agency's (ARPA) general program. There was no significantly positive shift in best practice frontier for projects between 2009 and 2011. There was a significantly positive shift in the improvement of technology and a significantly negative shift in efficiency for the same period. Fama-MacBeth results show, with sales as the independent variable, that employees and R%D expense are significant but not project income. The stochastic frontier analysis reveals that the null hypothesis of no inefficiency effects is rejected. As anticipated and substantiated, by applying the more appropriate parametric approach, the results did not confirm the findings of Naveh (2005), showing a positive association with initial product development and efficiency. As part of their first phase of product development, the findings suggest the presence of inefficiency effects of firms that participated in ARPA's general program. Journal: Int. J. of Operational Research Pages: 163-189 Issue: 2 Volume: 42 Year: 2021 Keywords: data envelopment analysis; DEA; Malmquist index; stochastic frontier analysis; SFA; Fama-MacBeth; programs; projects; efficiency. File-URL: http://www.inderscience.com/link.php?id=118975 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:2:p:163-189 Template-Type: ReDIF-Article 1.0 Author-Name: Mahsa Pouraliakbari-Mamaghani Author-X-Name-First: Mahsa Author-X-Name-Last: Pouraliakbari-Mamaghani Author-Name: Mohammad Mohammadi Author-X-Name-First: Mohammad Author-X-Name-Last: Mohammadi Author-Name: Alireza Arshadi-Khamseh Author-X-Name-First: Alireza Author-X-Name-Last: Arshadi-Khamseh Author-Name: Bahman Naderi Author-X-Name-First: Bahman Author-X-Name-Last: Naderi Title: A bi-objective robust possibilistic programming model for blood supply chain design in the mass casualty event response phase: a M/M/1/K queuing model with real world application Abstract: This paper presents a bi-objective blood supply chain design model for disaster relief. The model aims to simultaneously minimise the total costs of the supply chain, the trade-off between the total expected waiting times of patients in hospitals and the average hospital idle-time probability, unsatisfied demands and the average delivery time from mobile blood facilities to healthcare centres as the first, second, third and fourth objective functions. Since the critical parameters are tainted with great degree of epistemic uncertainty, basic chance constraint programming (BCCP) and robust fuzzy chance constraint programming (RFCCP) are utilised to deal with the uncertain nature of the supply chain. In order to solve the proposed model, two different multiple objective decision making approaches are used. The applicability of the proposed model for earthquake response phase is demonstrated via a real case study in a region of Iran. Useful managerial insights are also provided through conducting some sensitivity analyses. Journal: Int. J. of Operational Research Pages: 229-275 Issue: 2 Volume: 42 Year: 2021 Keywords: disaster management; blood supply chain network design; queuing theory; ε-constraint method; TH method; waiting times; robust possibilistic programming. File-URL: http://www.inderscience.com/link.php?id=118976 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:2:p:229-275 Template-Type: ReDIF-Article 1.0 Author-Name: Meenakshi Sharma Author-X-Name-First: Meenakshi Author-X-Name-Last: Sharma Author-Name: Manisha Sharma Author-X-Name-First: Manisha Author-X-Name-Last: Sharma Author-Name: Sameer Sharma Author-X-Name-First: Sameer Author-X-Name-Last: Sharma Title: A new heuristic for flow shop scheduling problems minimising system utilisation time subject to minimum makespan Abstract: This paper presents a heuristic algorithm to solve flow shop scheduling problems (FSSP) with the criterion to minimise the system utilisation time with minimum of maximum completion time (makespan). The proposed algorithm can solve FSSP under both the constraints in all the situations, which to the best of our knowledge has never been studied previously to this extent. To investigate the performance of the proposed heuristic and to compare it with some constructive benchmark heuristics, a number of test problems are solved and the results are reported. Computational results demonstrate that the newly developed heuristic significantly outperforms the other constructive heuristics reported in the literature in terms of solution quality. Journal: Int. J. of Operational Research Pages: 190-228 Issue: 2 Volume: 42 Year: 2021 Keywords: flow shop scheduling; makespan; delay time; heuristic; utilisation time. File-URL: http://www.inderscience.com/link.php?id=118984 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:2:p:190-228 Template-Type: ReDIF-Article 1.0 Author-Name: M.I. Nafeesathul Basariya Author-X-Name-First: M.I. Nafeesathul Author-X-Name-Last: Basariya Author-Name: Murugesan Punniyamoorthy Author-X-Name-First: Murugesan Author-X-Name-Last: Punniyamoorthy Title: A data analysis framework to predict the behaviour of macroeconomic indicators of countries Abstract: The impact of macroeconomic indicators on the economy of countries is difficult to establish correctly as the effects of these indicators are nonlinear and time variant. In this study, we have evolved new means to generate stationarity of such time series data. We have grouped the countries based on the mathematical model arrived during the stationarity test of economic indicators to analyse the pattern and magnitude of indicators that influences the economy and to suggest measures to follow the best economy in the group. The consumer price index and stock index data of countries like the USA, the UK, Brazil, India, Estonia and Latvia are considered for this purpose. The pattern of consumer price index and stock index of all the countries selected irrespective of their growth, was affected during the global financial crisis occurred during the year 2007 to 2009. The remedial measures to follow to reduce the gap are suggested. Journal: Int. J. of Operational Research Pages: 107-129 Issue: 1 Volume: 42 Year: 2021 Keywords: stationarity; macroeconomic indicators; consumer price index; stock index. File-URL: http://www.inderscience.com/link.php?id=117707 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:1:p:107-129 Template-Type: ReDIF-Article 1.0 Author-Name: Subrata Kumar Patra Author-X-Name-First: Subrata Kumar Author-X-Name-Last: Patra Author-Name: Tilak Raj Author-X-Name-First: Tilak Author-X-Name-Last: Raj Author-Name: B.B. Arora Author-X-Name-First: B.B. Author-X-Name-Last: Arora Title: An analysis of selected barriers towards the implementation of an energy efficient sustainable manufacturing system: a graph theoretic approach Abstract: The challenges such as environmental degradation, diminishing natural resources, health issues, etc. posed by many of the existing manufacturing practices act as a fertile ground for evolving newer techniques which are bereft of such drawbacks. Sustainable manufacturing is the antithesis to the problems inherent to the traditional manufacturing practices. Increasing social, economic and environmental challenges, typically associated with the traditional manufacturing processes can be addressed through sustainable practices. However, implementation of sustainable manufacturing system (SMS) within an industrial setup is a formidable task because of the existence of several multidimensional barriers associated with it. Hence, a holistic study of the manufacturing system is essential to evolve strategies for overcoming these barriers. The current study analyses these barriers using graph theoretic approach (GTA). Journal: Int. J. of Operational Research Pages: 34-55 Issue: 1 Volume: 42 Year: 2021 Keywords: sustainable manufacturing system; SMS; intensity of barriers; IOB; graph theoretic approach; GTA; multi-criteria decision-making; MCDM; variable permanent function; VPF. File-URL: http://www.inderscience.com/link.php?id=117708 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:1:p:34-55 Template-Type: ReDIF-Article 1.0 Author-Name: Priyanka Kalita Author-X-Name-First: Priyanka Author-X-Name-Last: Kalita Author-Name: Gautam Choudhury Author-X-Name-First: Gautam Author-X-Name-Last: Choudhury Title: Analysis of batch arrival single server queue with random vacation policy and two types of general heterogeneous repeated service Abstract: This article deals with batch arrival single server queue with random vacation policy and two types of general heterogeneous repeated service. We have obtained some explicit expressions for steady-state queue size distribution at service completion point and steady-state system size probabilities. Some significant measures such as mean system size, Laplace-Stieltjes transform of waiting time and its corresponding mean value have also obtained for the system. An optimal cost policy has been developed regarding the average cost function to determine the optimum mean service time of type 1 and type 2 services. Journal: Int. J. of Operational Research Pages: 131-162 Issue: 2 Volume: 42 Year: 2021 Keywords: MX/G/1 queue; random vacation policy; RVP; optional repeated service; embedded Markov chain; Markov regenerative process; MRGP cost optimal policy. File-URL: http://www.inderscience.com/link.php?id=118997 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:42:y:2021:i:2:p:131-162 Template-Type: ReDIF-Article 1.0 Author-Name: I. Padmavathi Author-X-Name-First: I. Author-X-Name-Last: Padmavathi Author-Name: B. Sivakumar Author-X-Name-First: B. Author-X-Name-Last: Sivakumar Title: A postponed inventory system with modified M vacation policy Abstract: In this article, we analyse a postponed inventory system with a single server under modified M vacation policy, where the server can take atmost M inactive mode. We assume that the demand process follows a Markovian arrival process and (<i>s</i>, <i>S</i>) ordering policy with exponential lead time. During the inactive mode, the server can be idle or go on vacation, which occurs due to the depletion of inventory. In every inactive mode, server avails the inactive idle period first followed by a vacation period. Inactive idle period and vacation period follow independent phase type distribution. The demand that arrives during the server inactive mode enters the pool of infinite size. The server selects a demand one by one on FCFS rule from the pool, as long as the inventory level is greater than the reorder point and inter selection time follows exponential distribution. A quasi birth and death process is formulated to analyse the system and solved by using the matrix-geometric method. We explicit some system performance measures on the steady state and some illustrative examples are discussed numerically. Journal: Int. J. of Operational Research Pages: 71-113 Issue: 1 Volume: 41 Year: 2021 Keywords: postponed inventory system; (s, S) ordering policy; modified vacation policy; matrix-geometric method. File-URL: http://www.inderscience.com/link.php?id=115415 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:1:p:71-113 Template-Type: ReDIF-Article 1.0 Author-Name: A.N. Senthilvel Author-X-Name-First: A.N. Author-X-Name-Last: Senthilvel Author-Name: S. Umamaheswari Author-X-Name-First: S. Author-X-Name-Last: Umamaheswari Author-Name: C. Arumugam Author-X-Name-First: C. Author-X-Name-Last: Arumugam Title: Dynamic analysis to set idle time between jobs on a single machine Abstract: Scheduling problems are common phenomena in everyday life. Most of the scheduling algorithms do not allow the resources to be kept idle when the jobs are waiting for its turn. However, scheduling of jobs with idle time insertion is desirable when early penalties are significantly large. Instead of starting a job immediately, deferring it for a while may facilitate to meet its due date. The problem considered here is to find the optimal schedule so as to minimise the earliness and tardiness penalties. This paper proposes a technique to insert the idle time as suitable as possible while meeting due date. The proposed algorithm minimises the penalty, through the insertion of the idle time, up to the point where no further minimisation of the objective function is achieved. The set of upper and lower bounds on the objective function value is presented for the randomly generated problem set. To prove the effectiveness of the algorithm, 400 sets of different sizes ranging from 15 jobs to 100 jobs are solved. The proposed method can be used as a benchmark for future approaches in the area of specific due date scheduling. Journal: Int. J. of Operational Research Pages: 114-134 Issue: 1 Volume: 41 Year: 2021 Keywords: scheduling algorithm; job sequencing; NP class; heuristic approach; idle time; global optimisation. File-URL: http://www.inderscience.com/link.php?id=115416 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:1:p:114-134 Template-Type: ReDIF-Article 1.0 Author-Name: Malek Alzaqebah Author-X-Name-First: Malek Author-X-Name-Last: Alzaqebah Author-Name: Salwani Abdullah Author-X-Name-First: Salwani Author-X-Name-Last: Abdullah Author-Name: Rami Malkawi Author-X-Name-First: Rami Author-X-Name-Last: Malkawi Author-Name: Sana Jawarneh Author-X-Name-First: Sana Author-X-Name-Last: Jawarneh Title: Self-adaptive bee colony optimisation algorithm for the flexible job-shop scheduling problem Abstract: The bee colony optimisation (BCO) algorithm is a nature-inspired algorithm that models the natural behaviour of honey bees as they find nectar and share food sources information with other bees in the hive. This paper presents the BCO algorithm for the flexible job-shop scheduling problem (FJSP), furthermore, to improve the neighbourhood search in the BCO algorithm we introduce a self-adaptive mechanism to the BCO algorithm (self-adaptive-BCO algorithm) for adaptively selecting the neighbourhood structure to enhance the local intensification capability of the algorithm and to help the algorithm to escape from a local optimum. We perform computational experiments on three well-known benchmarks for FJSP. The BCO algorithm is compared with the self-adaptive-BCO algorithm to test the performance of the latter. The results demonstrate that the self-adaptive-BCO algorithm outperforms the BCO algorithm, the proposed approach also outperforms the best-known algorithms in some datasets and it is comparable with these algorithms in other datasets. Journal: Int. J. of Operational Research Pages: 53-70 Issue: 1 Volume: 41 Year: 2021 Keywords: bee colony optimisation; BCO; flexible job-shop; adaptive neighbourhood search strategy. File-URL: http://www.inderscience.com/link.php?id=115417 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:1:p:53-70 Template-Type: ReDIF-Article 1.0 Author-Name: M.K. Marichelvam Author-X-Name-First: M.K. Author-X-Name-Last: Marichelvam Author-Name: M. Geetha Author-X-Name-First: M. Author-X-Name-Last: Geetha Title: Solving industrial multiprocessor task scheduling problems using an improved monkey search algorithm Abstract: This paper addresses multiprocessor task scheduling in a multistage hybrid flowshop environment which has been proved to be strongly NP-hard. An improved monkey search algorithm (IMSA) is proposed to solve this problem. The objective is to minimise the makespan which is the completion time of all the tasks in the last stage. The proposed algorithm is tested with three types of problems. A real industrial data is first used. Then, random problem instances are generated and finally, the benchmark problems addressed in literature are also considered. In all the three cases, the results are compared with earlier reported algorithms in the literature and the computational results reveal that the proposed algorithm is competent. Journal: Int. J. of Operational Research Pages: 135-149 Issue: 1 Volume: 41 Year: 2021 Keywords: scheduling; hybrid flowshop; HFS; multiprocessor tasks scheduling; NP-hard; monkey search algorithm; MSA; makespan. File-URL: http://www.inderscience.com/link.php?id=115418 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:1:p:135-149 Template-Type: ReDIF-Article 1.0 Author-Name: Nesrin Halouani Author-X-Name-First: Nesrin Author-X-Name-Last: Halouani Title: A developed multi-criteria group decision-making method based on interval valued hesitant fuzzy linguistic term sets and mentality parameter Abstract: Hesitant fuzzy linguistic term set (HFLTS) can be considered as a very practical tool in addressing decision problems where people are hesitant to provide their linguistic assessments while avoiding the possible loss of information. Therefore, HFLTS enhances the flexibility to get and represent linguistic information. This paper deals with this kind of decision making problems by proposing the concept of interval valued hesitant fuzzy linguistic term sets (IVHFLTS) since it can be considered as an extension of both a linguistic term set and an interval-valued hesitant fuzzy set. This new combination deals with both quantitative and qualitative evaluations. By introducing the mentality parameter for IVHFLTS, we develop a multi-criteria group decision-making model to deal with hesitant fuzzy linguistic information which avoids the possible loss of information. In order to show the applicability and the efficiency of the proposed method, an example for the selection of the best alternative is given as well as the ranking of the alternatives from the best to worst. The promising numerical results prove that this model is available. Journal: Int. J. of Operational Research Pages: 4-26 Issue: 1 Volume: 41 Year: 2021 Keywords: multi-criteria group decision-making; hesitant fuzzy linguistic term sets; HFLTS; mentality parameter; valued interval. File-URL: http://www.inderscience.com/link.php?id=115419 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:1:p:4-26 Template-Type: ReDIF-Article 1.0 Author-Name: Bijoy Krishna Debnath Author-X-Name-First: Bijoy Krishna Author-X-Name-Last: Debnath Author-Name: Pinki Majumder Author-X-Name-First: Pinki Author-X-Name-Last: Majumder Author-Name: Uttam Kumar Bera Author-X-Name-First: Uttam Kumar Author-X-Name-Last: Bera Title: A FEPQ model of sustainable items with time and stock dependent demand under trade credit policy Abstract: Nowadays sustainable fuzzy economic production quantity (s-FEPQ) models gets more highlighted over classical fuzzy economic production quantity (EPQ) models. In this paper, we developed a fuzzy inventory model of sustainable items under time dependent quadratic rate of fuzzy demand and exponential holding cost where shortages are allowed and are fully backlogged considering obsolescence cost and carbon emission cost. Also the developed model is compared with stock dependent fuzzy demand. The proposed fuzzy inventory model is solved via generalised Hukuhara derivative approach. Two different cases are considered by using generalised Hukuhara: differentiability and generalised Hukuhara. For the first time, in this sustainable fuzzy EPQ model, an alternative approach of payment is proposed. After that, the proposed model has been solved by using multi-objective genetic algorithm. The proposed model and technique are lastly illustrated by providing numerical examples. The results from the two methods are compared and some sensitivity analyses both in tabular and graphical forms are presented and discussed. Journal: Int. J. of Operational Research Pages: 27-52 Issue: 1 Volume: 41 Year: 2021 Keywords: sustainable fuzzy EPQ model; fully backlogged shortages; carbon emission; trade credit; alternative approach of payment; generalised Hukuhara derivative approach. File-URL: http://www.inderscience.com/link.php?id=115420 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijores:v:41:y:2021:i:1:p:27-52