Template-Type: ReDIF-Article 1.0 Author-Name: Farshid Keynia Author-X-Name-First: Farshid Author-X-Name-Last: Keynia Author-Name: Azim Heydari Author-X-Name-First: Azim Author-X-Name-Last: Heydari Title: A new short-term energy price forecasting method based on wavelet neural network Abstract: A wavelet neural network (WNN) is proposed for short-term price forecasting (STPF) in electricity markets. Back propagation algorithm is used for training the wavelet neural network for prediction. Weights in the back propagation algorithm are usually initialised with small random values. If the random initial weights happen to be far from a suitable solution or near a poor local optimum, training may take a long time or get trapped in the local optimum. In this paper, we show that WNN has acceptable prediction properties compared to other forecasting techniques. We investigated proper weight initialisations of WNN, and proved that it attains a superior prediction performance. Finally, we used a two-step correlation analysis algorithm for input selecting. This algorithm selects the best relevant and non-redundant input features for WNN. Our model is examined for MCP prediction of the Spanish market and LMP forecasting in PJM (Pennsylvania, New Jersey and Maryland) market for the year 2002 and 2006 respectively. Journal: Int. J. of Mathematics in Operational Research Pages: 1-14 Issue: 1 Volume: 14 Year: 2019 Keywords: adaptive wavelet neural network; electricity market; location marginal price; short-term price forecasting; STPF. File-URL: http://www.inderscience.com/link.php?id=96975 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:1:p:1-14 Template-Type: ReDIF-Article 1.0 Author-Name: Promila Kumar Author-X-Name-First: Promila Author-X-Name-Last: Kumar Author-Name: Bharti Sharma Author-X-Name-First: Bharti Author-X-Name-Last: Sharma Title: Second order duality for variational problem via efficiency of higher order Abstract: A mixed type second order dual of a multiobjective variational problem has been considered. Notion of generalised second order (<i>F</i>, <i>ρ</i>, <i>θ</i>, <i>m</i>)-invexity is introduced which is utilised to obtain duality results using efficiency of higher order as optimality criteria. Generalised second order (<i>F</i>, <i>ρ</i>, <i>θ</i>, <i>m</i>)-invexity assumptions broadens the domain of the problem, whereas efficiency of higher order leads to stronger results. Journal: Int. J. of Mathematics in Operational Research Pages: 15-29 Issue: 1 Volume: 14 Year: 2019 Keywords: second order duality; variational problem; efficiency of higher order. File-URL: http://www.inderscience.com/link.php?id=96976 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:1:p:15-29 Template-Type: ReDIF-Article 1.0 Author-Name: Raghu Nandan Giri Author-X-Name-First: Raghu Nandan Author-X-Name-Last: Giri Author-Name: Shyamal Kumar Mondal Author-X-Name-First: Shyamal Kumar Author-X-Name-Last: Mondal Author-Name: Manoranjan Maiti Author-X-Name-First: Manoranjan Author-X-Name-Last: Maiti Title: Joint replenishment model of both-ways and one-way substitution among products in fixed time horizon Abstract: A general joint replenishment model (JRM) has been developed for two substitutable products with different demand structures depending on their prices and availabilities over the time cycle. When both products are available, the demand of a substitute product deceases against its own price and increases with the other's price. When one product is out of stock, a portion of demand of the stock-out product goes to the available product. The model is formulated to determine the optimal order quantities and total profits for different scenarios are determined using the classical optimisation method and parametric study. The optimal criteria for maximum profit is outlined and the model is illustrated numerically. Some sensitivity analyses with different substitution ratios are performed and some interesting conclusions have been derived. Journal: Int. J. of Mathematics in Operational Research Pages: 30-52 Issue: 1 Volume: 14 Year: 2019 Keywords: joint replenishment model; substitutable products; degree of substitution; fixed time horizon. File-URL: http://www.inderscience.com/link.php?id=96977 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:1:p:30-52 Template-Type: ReDIF-Article 1.0 Author-Name: Sara Nakhjirkan Author-X-Name-First: Sara Author-X-Name-Last: Nakhjirkan Author-Name: Farimah Mokhatab Rafiei Author-X-Name-First: Farimah Mokhatab Author-X-Name-Last: Rafiei Author-Name: Ali Husseinzadeh Kashan Author-X-Name-First: Ali Husseinzadeh Author-X-Name-Last: Kashan Title: Developing an integrated decision making model in supply chain under demand uncertainty using genetic algorithm and network data envelopment analysis Abstract: Nowadays, organisations have recognised the importance of integrated decision making to improve supply chain performance. Since organisations cooperate with each other as a network, any ineffectiveness and inefficiency will be getting more highlighted and integration has become more important. This research describes a four echelon supply chain including supplier, producer, distributor and customer levels. The considered problem is a location routing inventory problem with uncertain demand. To validate integrated mathematical model several problems have been generated and solved using GAMS software. Results show solving time increases exponentially as problems dimension increases, which represents problem's complexity. Therefore, a heuristic genetic algorithm base on NDEA selection method is proposed. To evaluate proposed algorithm's effectiveness, generated problems have been solved by proposed method and three famous selection methods. Obtained results are compared by Wilcoxon test which represents the proposed algorithm's effectiveness. Journal: Int. J. of Mathematics in Operational Research Pages: 53-81 Issue: 1 Volume: 14 Year: 2019 Keywords: supply chain; integrated decision making; mathematical modelling; MINLP; location-inventory-routing problem; demand uncertainty; genetic algorithm; network data envelopment analysis; NDEA. File-URL: http://www.inderscience.com/link.php?id=96979 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:1:p:53-81 Template-Type: ReDIF-Article 1.0 Author-Name: Jie Chen Author-X-Name-First: Jie Author-X-Name-Last: Chen Author-Name: Zhixiang Chen Author-X-Name-First: Zhixiang Author-X-Name-Last: Chen Title: A new optimal multi-product (Q, R, SS) policy with multivariate Markov stochastic demand forecasting model Abstract: Multi-product inventory control is a challenging problem. Since its complexity in computation, many prior studies simplify the modelling conditions to assume that the demands are independent. In this paper, we consider a multi-product inventory system with stochastic demands which have multivariate Markov transition characteristics. We first study the demand transition process based on multivariate Markov theory, and construct a multivariate Markov demand model to forecast the stochastic demands of multiple products. Then, we propose a new optimisation model of inventory decision for multi-product under the multivariate Markov demand transition pattern. By solving the optimal solution of the model, we propose an optimal (<i>Q</i>, <i>R</i>, <i>SS</i>) policy to decide the ordering quantity <i>Q</i>, ordering point <i>R</i>, and safety stock <i>SS</i>. At last, we use a numerical example to demonstrate the application feasibility and efficiency of the proposed method. Journal: Int. J. of Mathematics in Operational Research Pages: 82-105 Issue: 1 Volume: 14 Year: 2019 Keywords: demand forecasting; stochastic demand; multi-product inventory system; multivariate Markov model; optimal (Q, R, SS) policy. File-URL: http://www.inderscience.com/link.php?id=96980 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:1:p:82-105 Template-Type: ReDIF-Article 1.0 Author-Name: Himani Dem Author-X-Name-First: Himani Author-X-Name-Last: Dem Author-Name: S.R. Singh Author-X-Name-First: S.R. Author-X-Name-Last: Singh Author-Name: Leena Parasher Author-X-Name-First: Leena Author-X-Name-Last: Parasher Title: Optimal strategy for an inventory model based on agile manufacturing under imperfect production process Abstract: This paper presents a production inventory model over infinite planning horizon with manufacturing process producing both perfect as well as imperfect items. Demand is stock dependent for perfect quality items and for imperfect items it depends on the reduction rate of selling price and the amount of imperfect production. The production rate is a function of demand. Reliability of the manufacturing system is assumed to be exponentially decreasing function of time. The objective is to determine the optimal policy for production system which maximises the total profit subject to some constraints under consideration. The results are discussed with a numerical example to illustrate the theory. The effects of important parameters on decision policy are also analysed through sensitivity analysis. Journal: Int. J. of Mathematics in Operational Research Pages: 106-122 Issue: 1 Volume: 14 Year: 2019 Keywords: imperfect production; agile/volume flexible manufacturing system; stock dependent demand; reduction rate. File-URL: http://www.inderscience.com/link.php?id=96981 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:1:p:106-122 Template-Type: ReDIF-Article 1.0 Author-Name: Soumita Kundu Author-X-Name-First: Soumita Author-X-Name-Last: Kundu Author-Name: Tripti Chakrabarti Author-X-Name-First: Tripti Author-X-Name-Last: Chakrabarti Title: A fuzzy rough integrated multi-stage supply chain inventory model with carbon emissions under inflation and time-value of money Abstract: Growing consciousness about environment compel governments across nations to enact legislation to reduce the greenhouse gas emission from industries. Recently, many investigations have been done on supply chain model imposing carbon regulation policies. But the effect of inflation and time value of money are overlooked. Here, we extended our research by considering the concept of inflation and time value of money in fuzzy rough environment where the cost coefficients are taken as trapezoidal fuzzy rough variables. In order to obtain optimistic and pessimistic equivalent of fuzzy rough objective function we use fuzzy rough expectation operator based on trust measure theory. Optimal inventory replenishment policy is obtained by using 'interior point' algorithm in MATLAB R2013a and sensitivity analysis is also presented to explore the effect of changes in carbon tax, net discount rate of inflation and optimistic-pessimistic parameter on the optimal solution. Journal: Int. J. of Mathematics in Operational Research Pages: 123-145 Issue: 1 Volume: 14 Year: 2019 Keywords: integrated supply chain; shipment; inflation; greenhouse gas emission; emissions tax; fuzzy rough variable. File-URL: http://www.inderscience.com/link.php?id=96984 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:1:p:123-145 Template-Type: ReDIF-Article 1.0 Author-Name: Iñigo L. Ansorena Author-X-Name-First: Iñigo L. Author-X-Name-Last: Ansorena Title: Work planning optimisation in ports: a simplex application Abstract: This paper presents an optimisation of the work plan at the gate of Barcelona container terminal (also known as TCB). The optimisation problem is formulated in accordance with the average traffic flow as a linear programming (LP) problem. Constraints of the LP problem are based on the data collected at the gate of TCB. The LP problem is solved by simplex algorithm and the solution includes: First, the value of the objective function (that is the feasible solution that minimises the number of clerks at the gate throughout a day); and second, the value, contribution to the objective, reduced cost, and range of optimality for each decision variable. Once the optimal solution has been achieved a sensitivity analysis is developed. The methodological procedure presented in this paper is general enough to be applied to any other container terminal. Journal: Int. J. of Mathematics in Operational Research Pages: 146-155 Issue: 1 Volume: 14 Year: 2019 Keywords: ports; queues; trucks; container terminal; gate; linear programming; simplex; scheduling; optimisation; clerks; productivity; work planning; application. File-URL: http://www.inderscience.com/link.php?id=96985 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:1:p:146-155 Template-Type: ReDIF-Article 1.0 Author-Name: R. Udayakumar Author-X-Name-First: R. Author-X-Name-Last: Udayakumar Author-Name: K.V. Geetha Author-X-Name-First: K.V. Author-X-Name-Last: Geetha Title: A two-level supply chain model with trade credit and imperfect production process Abstract: In this article, we discuss a production-distribution inventory model with a single-vendor and single buyer under imperfect production process. Trade credit is offered by the supplier, who encourages the retailer to buy more products. The lead time and the vendor's setup cost are reduced by an added cost. Two models are proposed in this article. In the first model, the lead time demand is allowed to follow a normal distribution and another model is framed with distribution free lead time demand. The objective of this work is to frame the model under imperfect production process and delay in payment and to investigate the impact of product defective rate on the expected total cost of the integrated system. The optimal values of order quantity, lead time, setup cost and the number of shipments from vendor to the buyer are found. Efficient computational algorithms for both the models are designed and managerial insights are obtained. Journal: Int. J. of Mathematics in Operational Research Pages: 157-188 Issue: 2 Volume: 14 Year: 2019 Keywords: supply chain; setup cost; controllable lead time; trade credit; imperfect production process. File-URL: http://www.inderscience.com/link.php?id=97753 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:2:p:157-188 Template-Type: ReDIF-Article 1.0 Author-Name: Karol Rosen Author-X-Name-First: Karol Author-X-Name-Last: Rosen Title: Large deviations for the overflow level of G/G/1 queues in series Abstract: We present a result characterising the large deviations behaviour of the total overflow level in a cycle starting with zero customers for a system of <i>G</i>/<i>G</i>/1 queues in series. We also present large deviations results for the total overflow level as seen by a random customer and in stationarity. We prove that the large deviations behaviour of the total overflow level for all three distributions, in a cycle, as seen by a random customer and in stationarity, have the same decay rate. We find the most likely path to have overflow in the system. Based on those results we propose a state-independent importance sampling algorithm. We also give conditions under which that algorithm is asymptotically efficient. By means of numerical simulation, we provide evidence of the advantages of this algorithm. Journal: Int. J. of Mathematics in Operational Research Pages: 189-220 Issue: 2 Volume: 14 Year: 2019 Keywords: large deviations; G/G/1 queues in series; rare event simulation; importance sampling; exponential twist; palm distribution; overflow level; asymptotic efficiency; stationary distribution; cycle. File-URL: http://www.inderscience.com/link.php?id=97755 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:2:p:189-220 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 server breakdown and repair, stand-by server and single vacation Abstract: In this paper, we discuss a non-Markovian batch arrival general bulk service single server queueing system with server breakdown and repair, single vacation and stand-by server. There is a stand-by server which is employed during the period for which the regular server remains under repair. Both the servers serve the customer under general bulk service rule. Suppose at the instant main servers service completion if the queue length is less than 'a' then the main server goes for a vacation. Suppose at the instant of repair completion or vacation completion if the system size is less than 'a' then the main server stays in the system and waits for the next batch of arriving customers. The probability generating function of queue size at an arbitrary time and some performance measures of the system are derived. An extensive numerical result for a particular case of the model is illustrated. Journal: Int. J. of Mathematics in Operational Research Pages: 221-235 Issue: 2 Volume: 14 Year: 2019 Keywords: general bulk service; single vacation; stand-by server; non-Markovian queue; breakdown and repair. File-URL: http://www.inderscience.com/link.php?id=97756 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:2:p:221-235 Template-Type: ReDIF-Article 1.0 Author-Name: Yogita Kansal Author-X-Name-First: Yogita Author-X-Name-Last: Kansal Author-Name: P.K. Kapur Author-X-Name-First: P.K. Author-X-Name-Last: Kapur Author-Name: Uday Kumar Author-X-Name-First: Uday Author-X-Name-Last: Kumar Author-Name: Deepak Kumar Author-X-Name-First: Deepak Author-X-Name-Last: Kumar Title: Prioritising vulnerabilities using ANP and evaluating their optimal discovery and patch release time Abstract: Method for filtering and identifying a vulnerability class that has high probability of occurrence is needed by organisations to patch their software in a timely manner. In this paper, our first step is to filter the most frequently observed vulnerability type/class through a multi-criteria decision making that involves dependency among various criteria and feedback from various alternatives, known as analytic network process. We will also formulate a cost model to provide a solution to the developers facing high revenue debt because of the occurrence of highly exploited vulnerabilities belonging to the filtered group. The main aim of formulating the cost model is to evaluate the optimal discovery and patch release time such that the total developer's cost could be minimised subject to risk constraints. To illustrate the proposed approach, reported vulnerabilities of Google Chrome with high exploitability have been examined at its source level. Journal: Int. J. of Mathematics in Operational Research Pages: 236-267 Issue: 2 Volume: 14 Year: 2019 Keywords: vulnerability; multi criteria decision making; analytical network process; optimisation; patches. File-URL: http://www.inderscience.com/link.php?id=97758 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:2:p:236-267 Template-Type: ReDIF-Article 1.0 Author-Name: Seyed Mojtaba Sajadi Author-X-Name-First: Seyed Mojtaba Author-X-Name-Last: Sajadi Author-Name: Azar Alizadeh Author-X-Name-First: Azar Author-X-Name-Last: Alizadeh Author-Name: Mostafa Zandieh Author-X-Name-First: Mostafa Author-X-Name-Last: Zandieh Author-Name: Fereshteh Tavan Author-X-Name-First: Fereshteh Author-X-Name-Last: Tavan Title: Robust and stable flexible job shop scheduling with random machine breakdowns: multi-objectives genetic algorithm approach Abstract: In this paper, robust and stable scheduling for a flexible job-shop problem with random machine breakdowns has been discussed. A two-stage genetic algorithm is used to generate the predictive schedule. The first stage optimises the primary objective, which minimises the makespan, where all data is considered to be deterministic with no expected disruptions. The second stage optimises two objectives, makespan and stability, function in the presence of random machine breakdowns. For the second stage two different versions of multi-objective genetic algorithm, non-dominated sorting genetic algorithm II and non-dominated ranking genetic algorithm, is used. A simulator is proposed to simulate random machine breakdowns. An experimental study and analysis of variance is conducted to study the results of each multi-objective algorithm and breakdown simulator. The results of their comparison indicate that, non-dominated ranking genetic algorithm (NRGA) performs better and also shows a significant difference between various repair times in the proposed breakdown simulator. Journal: Int. J. of Mathematics in Operational Research Pages: 268-289 Issue: 2 Volume: 14 Year: 2019 Keywords: flexible job-shop scheduling problem; machine breakdowns; robustness; stability; SMEs. File-URL: http://www.inderscience.com/link.php?id=97759 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:2:p:268-289 Template-Type: ReDIF-Article 1.0 Author-Name: Dharamender Singh Author-X-Name-First: Dharamender Author-X-Name-Last: Singh Title: Production inventory model of deteriorating items with holding cost, stock, and selling price with backlog Abstract: This paper deals, production-inventory model with stock-dependent and selling price dependent demand. Demand rate is linearly increasing with stock and time, decreasing with a selling price of the item. Shortages are allowed and partially back ordered at the rate of decreasing waiting time of next replenishment. This model is classified as the deterioration rate is constant, and holding cost-based as constant. The model is solved numerically and analytically by minimising the total inventory cost and maximises the total profit at the last sensitivity analysis has been performed to show the nature of model in every parameter on the optimum solution. We have presented a solution-search procedure to find the preservation technology and optimal production time. Journal: Int. J. of Mathematics in Operational Research Pages: 290-305 Issue: 2 Volume: 14 Year: 2019 Keywords: deterioration; inventory; preservation technology; production; shortage. File-URL: http://www.inderscience.com/link.php?id=97760 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:2:p:290-305 Template-Type: ReDIF-Article 1.0 Author-Name: Mohamed Abdel-Baset Author-X-Name-First: Mohamed Author-X-Name-Last: Abdel-Baset Author-Name: Yongquan Zhou Author-X-Name-First: Yongquan Author-X-Name-Last: Zhou Author-Name: Ibrahim Hezam Author-X-Name-First: Ibrahim Author-X-Name-Last: Hezam Title: Use of a sine cosine algorithm combined with Simpson method for numerical integration Abstract: The sine cosine algorithm (SCA) is one of the most recent nature-inspired meta-heuristic optimisation algorithm, which the mathematical model based on sine and cosine functions. SCA has validated excellent performance in solving continuous problems and engineering optimisation problems. In this paper, we propose a new algorithm that encompasses the features of sine cosine algorithm and Simpson method (SCA-SM). The proposed procedure consists of two phases: in the first phase, the of sine cosine algorithm are used to find the optimal segmentation points on the integral interval of an integrand. In the second phase, the approximate integral value of the integrand is then calculated by a Simpson method. Numerical simulation results show that the algorithm offers an effective way to calculate numerical value of definite integrals, and it has a high convergence rate, high accuracy and robustness. Journal: Int. J. of Mathematics in Operational Research Pages: 307-318 Issue: 3 Volume: 14 Year: 2019 Keywords: sine cosine algorithm; SCA; meta-heuristics; optimisation; Simpson method; numerical integration. File-URL: http://www.inderscience.com/link.php?id=99381 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:3:p:307-318 Template-Type: ReDIF-Article 1.0 Author-Name: Sudipta Sinha Author-X-Name-First: Sudipta Author-X-Name-Last: Sinha Author-Name: Nikunja Mohan Modak Author-X-Name-First: Nikunja Mohan Author-X-Name-Last: Modak Title: An EPQ model in the perspective of carbon emission reduction Abstract: One of the major reasons behind the abnormal increase of Earth's temperature is the uncontrollable emission of CO<SUB align="right"><SMALL>2</SMALL></SUB> of production houses. Industrialists are very much interested to enhance their profit only instead of greater interest of the society. The paper develops an economic production quantity (EPQ) model reckoning the aspects of carbon emission and carbon trading. A production house has to pay compulsory tax for carbon emission and incurs a penalty cost for the emission of excess carbon dioxide than its permissible limit. The producer is able to earn revenue by the way of carbon trading by controlling carbon emission within the permissible limit. Plantation of trees can effectively mitigate emission. Numerical examples are given to illustrate the validity of the proposed model and comparison of result between with and without plantation is provided. Comprehensive sensitivity analysis of various parameters has also been carried out. Journal: Int. J. of Mathematics in Operational Research Pages: 338-358 Issue: 3 Volume: 14 Year: 2019 Keywords: economic production quantity; EPQ; carbon emission; carbon trading; cap and trade; penalty tax; plantation. File-URL: http://www.inderscience.com/link.php?id=99382 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:3:p:338-358 Template-Type: ReDIF-Article 1.0 Author-Name: G.K. Gupta Author-X-Name-First: G.K. Author-X-Name-Last: Gupta Author-Name: A. Banerjee Author-X-Name-First: A. Author-X-Name-Last: Banerjee Title: Steady state analysis of system size-based balking in M/Mb/1 queue Abstract: In this paper we consider a single server Poisson queue where customers are served in batches of fixed size. The inter arrival time and the service time are considered to be exponentially distributed. The customers upon arrival may decide to join the system or not to join the system by observing the system length. They may join or balk the system with certain probability. Using probability generating function method we obtain the closed form expression for steady state queue length distribution, expected system (queue) length and expected waiting time of a customer in the system (queue). Finally, several numerical results are discussed in the form of table and graphs to explore the sensitivity of system parameters on key performance measures. Journal: Int. J. of Mathematics in Operational Research Pages: 319-337 Issue: 3 Volume: 14 Year: 2019 Keywords: balking; bulk service queue; fixed batch size; probability generating function method; steady state. File-URL: http://www.inderscience.com/link.php?id=99383 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:3:p:319-337 Template-Type: ReDIF-Article 1.0 Author-Name: R. Uthayakumar Author-X-Name-First: R. Author-X-Name-Last: Uthayakumar Author-Name: M. Ganesh Kumar Author-X-Name-First: M. Ganesh Author-X-Name-Last: Kumar Title: Single-vendor multi-buyer integrated inventory system for multi-item Abstract: In this paper, a single-vendor multi-buyer supply chain system is considered in which several products. The demand of this supply chain for each product is a stochastic variable and it is assumed to follow a normal distribution. The lead time of receiving products from vendor to buyer is a variable which controllable by the adding extra cost. During the consumption period, the shortages are allowed and they are completely backlogged in the next replenishment. The production process is assumed to be imperfect, i.e., all the finished products need not consumable, so the buyer implements a screening process to separate the defective and non-defective items and the vendor pay warranty cost for each defective item to the buyer. We investigated the economic order quantity (EOQ), lead time and number of shipments such that total cost of the supply chain have been minimised. At last numerical illustration and sensitivity analysis are given. Journal: Int. J. of Mathematics in Operational Research Pages: 359-376 Issue: 3 Volume: 14 Year: 2019 Keywords: controllable lead time; defective items; economic order quantity; inspection; integrated model; multi-item; multi-buyer; process quality. File-URL: http://www.inderscience.com/link.php?id=99384 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:3:p:359-376 Template-Type: ReDIF-Article 1.0 Author-Name: Sumit Saha Author-X-Name-First: Sumit Author-X-Name-Last: Saha Author-Name: Nabendu Sen Author-X-Name-First: Nabendu Author-X-Name-Last: Sen Title: An inventory model for deteriorating items with time and price dependent demand and shortages under the effect of inflation Abstract: Variation of demand with time and price is one of the major concerns in any inventory system. Several studies report situations where demand varies with time and price separately. A few researchers have considered the joint effect of demand with price and time on optimal solutions. Thus, a suitable inventory policy in this regard is always sought for. This paper presents an inventory model with selling price and time dependent demand, constant holding cost and time dependent deterioration. In this model, shortages are assumed to be partially backlogged. It is designed keeping in mind to optimise total inventory cost under the effect of inflation. For the solution of the model, an algorithm is proposed and illustrated with numerical values of system parameters. The optimal results are also presented graphically. Finally, sensitivity analysis is performed for different parametric values of system parameters. Journal: Int. J. of Mathematics in Operational Research Pages: 377-388 Issue: 3 Volume: 14 Year: 2019 Keywords: time and price dependent demand; deterioration; partial backlogging; maximum life time of item; inflation. File-URL: http://www.inderscience.com/link.php?id=99385 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:3:p:377-388 Template-Type: ReDIF-Article 1.0 Author-Name: Gera Workie Woubante Author-X-Name-First: Gera Workie Author-X-Name-Last: Woubante Author-Name: Abebaw Bizuneh Alemu Author-X-Name-First: Abebaw Bizuneh Author-X-Name-Last: Alemu Author-Name: Senait Asmelash Gebrehiwot Author-X-Name-First: Senait Asmelash Author-X-Name-Last: Gebrehiwot Title: Ensure optimum profit using linear programming a product-mix of textile manufacturing companies Abstract: An optimum profit is to be guaranteed for a rapidly changing manufacturing situation when the best product mix is produced. The product mix determination problem involves determining the optimal level of different products given a set of capacity limitations. This paper addresses a tool linear programming in operations research for determining the optimal allocation of limited resources in order to maximise profit. Fortunately, having well-formulated model, solution software package Excel Solver helps to determine the best combination of available resources. This paper considers a textile industrial unit in Ethiopia as a case study. In this company, the data gathered was used to estimate the parameters of the linear programming model. The findings of the study show that the profit of the company can be improved by 11.8% (= (66850232.79 &minus; 59793841.91 / 59793841.91)) if linear programming technique is used. This can be considered as a remarkable profit improvement. In addition, actual resource utilization can be significantly improved by adopting linear programming method. Journal: Int. J. of Mathematics in Operational Research Pages: 389-406 Issue: 3 Volume: 14 Year: 2019 Keywords: excel solver; linear programming; optimal profit; product mix; textile manufacturing. File-URL: http://www.inderscience.com/link.php?id=99386 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:3:p:389-406 Template-Type: ReDIF-Article 1.0 Author-Name: Zuhair A. Al-Hemyari Author-X-Name-First: Zuhair A. Author-X-Name-Last: Al-Hemyari Author-Name: H.A. Al-Dabag Author-X-Name-First: H.A. Author-X-Name-Last: Al-Dabag Author-Name: Ali Al-Humairi Author-X-Name-First: Ali Author-X-Name-Last: Al-Humairi Title: A class of always pooling shrinkage testimators for the Weibull model Abstract: Utilising the prior information or additional information from the past in new estimation processes has been receiving considerable attention in the last few decades - as such appears from the list of the references of this paper. In fact, the shrinkage testimators were developed originally for the purpose of utilising the prior information in new estimation problems. In this paper, we have developed a general class of shrinkage testimator, and because it always uses the prior value, are called the always pooling shrinkage testimator for any parameter or distribution. The expressions of bias, risk, risk ratio, relative efficiency, region and shrinkage weight function are derived. The dual importance of the proposed class of testimators are in using the prior information in both stages, something which has significant influence in increasing the relative efficiency and reduction of the sample size required. The comparisons, recommendations, discussions and limitations are provided in this paper. Journal: Int. J. of Mathematics in Operational Research Pages: 407-432 Issue: 3 Volume: 14 Year: 2019 Keywords: always pooling; shrinkage; Weibull failure model; shape parameter; censored data; bias ratio; relative risk. File-URL: http://www.inderscience.com/link.php?id=99387 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:3:p:407-432 Template-Type: ReDIF-Article 1.0 Author-Name: Ali Ebrahimnejad Author-X-Name-First: Ali Author-X-Name-Last: Ebrahimnejad Author-Name: Shokrollah Ziari Author-X-Name-First: Shokrollah Author-X-Name-Last: Ziari Title: New model for improving discrimination power in DEA based on dispersion of weights Abstract: One of the difficulties of data envelopment analysis (DEA) is the problem of deficiency discrimination among efficient decision making units (DMUs) and hence, yielding large number of DMUs as efficient ones. The main purpose of this paper is to overcome this inability. One of the methods for ranking efficient DMUs is minimising the coefficient of variation (CV) for inputs-outputs weights, which, was suggested by Bal et al. (2008). In this paper, we introduce a nonlinear model for ranking efficient DMUs based on modifying of the model suggested by Bal et al. and then we convert the nonlinear model proposed into a linear programming form. The motivation of this work is to linearise the existing nonlinear model which has the computational complexity. Journal: Int. J. of Mathematics in Operational Research Pages: 433-450 Issue: 3 Volume: 14 Year: 2019 Keywords: data envelopment analysis; DEA; ranking; extreme efficient; dispersion of weights. File-URL: http://www.inderscience.com/link.php?id=99388 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:3:p:433-450 Template-Type: ReDIF-Article 1.0 Author-Name: Phani Bushan Rao Peddi Author-X-Name-First: Phani Bushan Rao Author-X-Name-Last: Peddi Title: Evaluating fuzzy risk based on a new method of ranking fuzzy numbers using centroid of centroids Abstract: This paper describes a method to rank fuzzy numbers based on centroid of centroids of fuzzy numbers and emphasises the use of the subjectivity of the decision maker's view point, such as optimistic or pessimistic. Using the decision maker's view point and index of modality, a ranking index of each fuzzy number is calculated which serves as a criterion for ranking fuzzy numbers. The proposed fuzzy ranking method is used to analyse the fuzzy risk involved in manufacturing products by different companies, where the probability of failure of a product is represented by a fuzzy number. The proposed method is more flexible than the existing methods as it takes into consideration the degrees of confidence of decision maker's opinion in both the stages. Journal: Int. J. of Mathematics in Operational Research Pages: 451-472 Issue: 4 Volume: 14 Year: 2019 Keywords: centroid points; index of optimism; index of modality; fuzzy risk analysis; fuzzy numbers. File-URL: http://www.inderscience.com/link.php?id=100731 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:4:p:451-472 Template-Type: ReDIF-Article 1.0 Author-Name: S. Elizabeth Amudhini Stephen Author-X-Name-First: S. Elizabeth Amudhini Author-X-Name-Last: Stephen Author-Name: D. Christu Nesam David Author-X-Name-First: D. Christu Nesam Author-X-Name-Last: David Author-Name: A. Joe Ajay Author-X-Name-First: A. Joe Author-X-Name-Last: Ajay Title: Design optimisation of cost of the pressure vessel through MATLAB and simulation through ANSYS Abstract: The objective functions used in engineering optimisation are complex in nature with many variables and constraints. Conventional optimisation tools sometimes fail to give the global optimal points. Very popular methods like genetic algorithm, pattern search, simulated annealing, and gradient search are useful methods to find global optima related to engineering problems. This paper attempts to use new non-traditional optimisation algorithms which are used to find the minimum cost of designing a pressure vessel to obtain global optimum solutions. The cost, number of iterations and the total elapsed time to complete the problems are all compared using these ten non-traditional optimisation methods. The validation is done through simulation using ANSYS. Journal: Int. J. of Mathematics in Operational Research Pages: 473-494 Issue: 4 Volume: 14 Year: 2019 Keywords: pattern search; simulate annealing; GODLIKE; cuckoo search; firefly algorithm; flower pollination; ant lion optimiser; gravitational search algorithm; multi-verse optimiser; simulation ANSYS. File-URL: http://www.inderscience.com/link.php?id=100733 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:4:p:473-494 Template-Type: ReDIF-Article 1.0 Author-Name: Geovanna Villacreses Author-X-Name-First: Geovanna Author-X-Name-Last: Villacreses Author-Name: Javier Martínez-Gómez Author-X-Name-First: Javier Author-X-Name-Last: Martínez-Gómez Author-Name: Paola Quintana Author-X-Name-First: Paola Author-X-Name-Last: Quintana Author-Name: Ricardo A. Narváez C. Author-X-Name-First: Ricardo A. Narváez Author-X-Name-Last: C. Title: Geolocation of electric bikes recharging stations: City of Quito study case Abstract: The aim of this research was to develop a geographical information system with multi-criteria decision making methods for selecting the most feasible location to install electric bikes recharging stations in the City of Quito. For such purpose, the ideal solution-similarity preference ranking and weighted overlay techniques have been used as multi-criteria decision making methods. In addition, the analytic hierarchy process method was performed for calculating the weights of each criterion. Moreover, a standardisation process that consists of establishing an overall performance index to evaluate the results was applied. Finally, the Pearson correlation coefficient was used to analyse mutual correspondence between multi-criteria decision making methods. The resulting Pearson correlation coefficients indicate that the two selected multi-criteria decision making methods provided similar results. In this context, the methods analysed covered similar solutions and indicated that multi-criteria decision making methods are a powerful tool to select ideal locations for electric bikes recharging stations. Journal: Int. J. of Mathematics in Operational Research Pages: 495-516 Issue: 4 Volume: 14 Year: 2019 Keywords: optimal location; e-bikes; geographic information systems; GIS; multi-criteria decision making; MCDM methods. File-URL: http://www.inderscience.com/link.php?id=100735 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:4:p:495-516 Template-Type: ReDIF-Article 1.0 Author-Name: Charan Jeet Singh Author-X-Name-First: Charan Jeet Author-X-Name-Last: Singh Author-Name: Sandeep Kaur Author-X-Name-First: Sandeep Author-X-Name-Last: Kaur Author-Name: Madhu Jain Author-X-Name-First: Madhu Author-X-Name-Last: Jain Title: Analysis of bulk queue with additional optional service, vacation and unreliable server Abstract: The present investigation deals with the performance analysis of group input queueing system with unreliable server. The server is capable of rendering essential as well as optional services. After getting essential service, the customer may choose any one of the available optional services if required. The server has choice either to avail the vacation for the short period after completion of the service or may continue to provide the service to other customers. The server may fail at any instant of the essential/optional service and undergoes repair immediately. The queueing model is developed by introducing the supplementary variables corresponding to elapsed setup time, service time, and repair time and vacation duration for obtaining the queue size distribution. The maximum entropy principle is employed to determine the approximate results of the system state probabilities and the waiting time of the customers in the queue. The numerical simulation and sensitivity analysis are performed by taking the numerical illustration to study the effect of system parameters on the various performance measures and cost function. Journal: Int. J. of Mathematics in Operational Research Pages: 517-540 Issue: 4 Volume: 14 Year: 2019 Keywords: bulk queue; unreliable server; repair; essential service; optional service; vacation; supplementary variable. File-URL: http://www.inderscience.com/link.php?id=100738 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:4:p:517-540 Template-Type: ReDIF-Article 1.0 Author-Name: Umut Beşikçi Author-X-Name-First: Umut Author-X-Name-Last: Beşikçi Author-Name: Ümit Bilge Author-X-Name-First: Ümit Author-X-Name-Last: Bilge Author-Name: Gündüz Ulusoy Author-X-Name-First: Gündüz Author-X-Name-Last: Ulusoy Title: Resource portfolio problem under relaxed resource dedication policy in multi-mode multi-project scheduling Abstract: The most common approach in the multi-project scheduling literature considers resources as a common pool shared among all projects. However, different resource management strategies may be required for different problem environments. We present the relaxed resource dedication (RRD) policy, which prevents the sharing of resources among projects but allows resource transfers when a project starts after the completion of another one. We treat the case where the available amounts of resources - namely, the capacities - are decision variables subject to a limited budget. This capacity planning problem, called the resource portfolio problem, is investigated under the RRD policy employing both renewable and non-renewable resources with multiple modes of usage. A mixed integer linear programming model to minimise total weighted tardiness is proposed. To obtain some benchmark solutions for this hard problem, the branch and cut procedure of ILOG CPLEX is modified by customised branching strategies, feasible solution generation schemes and valid inequalities. Journal: Int. J. of Mathematics in Operational Research Pages: 541-567 Issue: 4 Volume: 14 Year: 2019 Keywords: multi-mode resource constrained multi-project scheduling; resource dedication; resource portfolio allocation; branch and cut. File-URL: http://www.inderscience.com/link.php?id=100739 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:4:p:541-567 Template-Type: ReDIF-Article 1.0 Author-Name: Y. Sarada Author-X-Name-First: Y. Author-X-Name-Last: Sarada Author-Name: R. Shenbagam Author-X-Name-First: R. Author-X-Name-Last: Shenbagam Title: On phase type arithmetico-geometric process and its application to deteriorating systems with warranty Abstract: This research article makes an attempt to introduce a phase type arithmetico-geometric process and illustrate its applicability to a deteriorating system with fixed warranty. Properties, renewal function, second moment and variance of the underlying counting process are derived analytically and supplemented numerically in the case of three distributions: exponential, Erlang distribution of order 3 and Coxian distribution of order 2. Sensitivity analysis and graphical illustrations are provided to highlight the effect of various cost parameters on the expected warranty cost by means of the Exponential and Erlang distribution of order 2. Journal: Int. J. of Mathematics in Operational Research Pages: 568-589 Issue: 4 Volume: 14 Year: 2019 Keywords: phase type distribution; arithmetico-geometric process; fixed warranty. File-URL: http://www.inderscience.com/link.php?id=100740 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:4:p:568-589 Template-Type: ReDIF-Article 1.0 Author-Name: Chao Wei Author-X-Name-First: Chao Author-X-Name-Last: Wei Title: Parameter estimation for partially observed linear stochastic system Abstract: This paper is concerned with the problem of parameter estimation for a partially observed linear stochastic system. The state estimator is obtained by using the continuous-time Kalman linear filtering theory. The likelihood function is given based on the innovation theorem and Girsanov theorem, the parameter estimator and error of estimation are derived. The strong consistency of the parameter estimator and the asymptotic normality of the error of estimation are proved by applying ergodic theorem, maximal inequality for martingale, Borel-Cantelli lemma and the central limit theorem for stochastic integrals. Journal: Int. J. of Mathematics in Operational Research Pages: 590-599 Issue: 4 Volume: 14 Year: 2019 Keywords: linear stochastic system; parameter estimation; state estimation; strong consistency; asymptotic normality; incomplete observation; operational research; Kalman linear filtering; error of estimation; likelihood function. File-URL: http://www.inderscience.com/link.php?id=100741 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:14:y:2019:i:4:p:590-599 Template-Type: ReDIF-Article 1.0 Author-Name: G. Ayyappan Author-X-Name-First: G. Author-X-Name-Last: Ayyappan Author-Name: T. Deepa Author-X-Name-First: T. Author-X-Name-Last: Deepa Title: Analysis of batch arrival bulk service queue with additional optional service multiple vacation and setup time Abstract: This paper studies an <i>M</i><SUP align="right"><SMALL>[<i>x</i>]</SMALL></SUP>/<i>G</i>(<i>a</i>, <i>b</i>)/1 queuing system with additional optional service, multiple vacation and setup time. After completing the first service, the customers may opt for the second service with probability α or leave the system with probability 1 &minus; α. After completing a bulk service, if the queue size is less than 'α', then the server leaves for a vacation of random length. When he returns from the vacation, if the queue length is still less than 'α', he leaves for another vacation and so on. This process continues until he finds at least 'α' customer in the queue. After a vacation, if the server finds at least 'α' customer waiting for service, he requires a setup time '<i>G</i>' to start the service. After this setup, he serves a batch of ξ customers (<i>a</i> &le; ξ &le; <i>b</i>). Using supplementary variable technique, the probability generating function (PGF) of the queue size, expected queue length, expected waiting time, expected busy period and expected idle period are derived. Numerical illustrations are presented to visualise the effect of system parameters. Journal: Int. J. of Mathematics in Operational Research Pages: 1-25 Issue: 1 Volume: 15 Year: 2019 Keywords: batch arrival; bulk service; additional optional service; multiple vacation; setup time. File-URL: http://www.inderscience.com/link.php?id=101609 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:1:p:1-25 Template-Type: ReDIF-Article 1.0 Author-Name: İmdat Kara Author-X-Name-First: İmdat Author-X-Name-Last: Kara Author-Name: Bahar Y. Kara Author-X-Name-First: Bahar Y. Author-X-Name-Last: Kara Title: Comments on the 'polynomial formulation and heuristic-based approach for the k-travelling repairman problem' Abstract: The paper 'polynomial formulation and heuristic-based approach for the k-travelling repairman problem' claims to present the first polynomial formulation for the k-travelling repairman problem (k-TRP). We first make some corrections on this formulation and we show that the first polynomial size formulation for k-TRP is the one proposed by Kara et al. (2008). Journal: Int. J. of Mathematics in Operational Research Pages: 26-32 Issue: 1 Volume: 15 Year: 2019 Keywords: repairman problem; k-travelling repairman problem; minimum latency problem; delivery man problem. File-URL: http://www.inderscience.com/link.php?id=101610 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:1:p:26-32 Template-Type: ReDIF-Article 1.0 Author-Name: Supriya Kar Author-X-Name-First: Supriya Author-X-Name-Last: Kar Author-Name: Aniruddha Samanta Author-X-Name-First: Aniruddha Author-X-Name-Last: Samanta Author-Name: Kajla Basu Author-X-Name-First: Kajla Author-X-Name-Last: Basu Title: Solution of fuzzy multi objective generalised assignment problem Abstract: In this paper, multi objective generalised assignment problem (MOGAP) with fuzzy parameters has been solved using three different approaches. Here, we consider three objective functions which are to be minimised. In the first approach, weighted sum method has been used and the problem is converted into a single objective one and then solved by extremum difference method (EDM) to get the optimal assignment. In the second one, modified fuzzy programming technique (MFPT) has been used for the same problem. Application of linear and exponential membership functions give comparative results with the goal that the better alternative can be obtained. The third one describes multi objective genetic algorithm (MOGA) to find the solution surface and the Pareto optimal front including the optimal assignment. The methods are demonstrated by a suitable numerical example. Journal: Int. J. of Mathematics in Operational Research Pages: 33-54 Issue: 1 Volume: 15 Year: 2019 Keywords: FMOGAP; extremum difference method; EDM; modified fuzzy programming technique; MFPT; multi objective genetic algorithm; MOGA. File-URL: http://www.inderscience.com/link.php?id=101611 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:1:p:33-54 Template-Type: ReDIF-Article 1.0 Author-Name: Nedal Tahat Author-X-Name-First: Nedal Author-X-Name-Last: Tahat Author-Name: Eddie Shahril Ismail Author-X-Name-First: Eddie Shahril Author-X-Name-Last: Ismail Author-Name: Ashraf H. Aljammal Author-X-Name-First: Ashraf H. Author-X-Name-Last: Aljammal Title: A cryptosystem based on chaotic maps and factoring problems Abstract: A cryptosystem allows a sender to send any confidential or private message using a receiver's public key and the receiver next confirms the integrity and validity of the received message using his own secret key. Cryptosystem algorithms can be categorised based on the type of security suppositions, for example discrete logarithm, factorisation, and elliptic curve hard problems, which are all currently believed to be unsolvable in a reasonable time of period. Recently, cryptosystems based on chaotic maps have been proposed. Due to some subtle and close relationship between the properties of traditional cryptosystems and chaotic-based systems, the idea of using chaotic in cryptography has received a great deal of attention from many cryptography's researchers. Therefore, to enhance system security, we explore the implementation of a cryptosystem algorithm based on both cryptographic and chaotic system characteristics. We also provide security against known cryptographic attacks and discuss the performance analysis of the developed system. Journal: Int. J. of Mathematics in Operational Research Pages: 55-64 Issue: 1 Volume: 15 Year: 2019 Keywords: cryptography; cryptosystem; factorisation; chaotic maps. File-URL: http://www.inderscience.com/link.php?id=101612 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:1:p:55-64 Template-Type: ReDIF-Article 1.0 Author-Name: Nurul Huda Mohamed Author-X-Name-First: Nurul Huda Author-X-Name-Last: Mohamed Author-Name: Said Salhi Author-X-Name-First: Said Author-X-Name-Last: Salhi Author-Name: Gábor Nagy Author-X-Name-First: Gábor Author-X-Name-Last: Nagy Author-Name: Nurul Akmal Mohamed Author-X-Name-First: Nurul Akmal Author-X-Name-Last: Mohamed Title: A matheuristic approach for the split delivery vehicle routing problem: an efficient set covering-based model with guided route generation schemes Abstract: The split delivery vehicle routing problem (SDVRP) is a relaxed version of the classical VRP where customers can be visited more than once. The SDVRP is also applicable for problems where one or more of the customers require a demand larger than the vehicle capacity. Constructive heuristics adapted from the parallel savings and the sweep methods are first proposed to generate a set of solutions which is then used in the new and more efficient set covering-based formulation which we put forward. An effective repair mechanism to remedy any infeasibility due to the set covering problem is presented. A reduced set of promising routes is used in our model, instead of the original set of routes, proposing and using well defined reduction schemes. This set covering-based approach is tested on large datasets from the literature with encouraging results. In brief, seven best solutions including ties are found among the 137 SDVRP instances. Journal: Int. J. of Mathematics in Operational Research Pages: 65-91 Issue: 1 Volume: 15 Year: 2019 Keywords: split deliveries; vehicle routing; set covering; hybrid method; matheuristic. File-URL: http://www.inderscience.com/link.php?id=101613 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:1:p:65-91 Template-Type: ReDIF-Article 1.0 Author-Name: K.V. Vijayashree Author-X-Name-First: K.V. Author-X-Name-Last: Vijayashree Author-Name: A. Anjuka Author-X-Name-First: A. Author-X-Name-Last: Anjuka Title: Exact stationary solution for a fluid queue driven by an M/M/1 queue with disaster and subsequent repair Abstract: This paper deals with the stationary analysis of a fluid queuing model driven by an <i>M/M/</i>1 queue subject to disaster and subsequent repair. Further, arrivals are allowed to join the background queuing model during the period of repair at a slower rate as compared to the arrivals during regular busy period of the server. Such a model was analysed earlier by Ammar (2014), however the model formulation and hence the main results are found to be incorrect. In this paper, the assumptions are suitably modified to ensure correctness, detailed mathematical analysis is carried out to find an explicit analytical expression for the buffer content distribution. The underlying system of differential difference equations that govern the process are solved using Laplace transform and generating function methodologies. The closed form expressions for the joint steady state probabilities of the state of the background queuing model and the content of the buffer are obtained in terms of modified Bessel function of the first kind. Journal: Int. J. of Mathematics in Operational Research Pages: 92-109 Issue: 1 Volume: 15 Year: 2019 Keywords: generating function; Laplace transform; steady state probabilities; buffer content distribution. File-URL: http://www.inderscience.com/link.php?id=101614 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:1:p:92-109 Template-Type: ReDIF-Article 1.0 Author-Name: Sanjay Singh Author-X-Name-First: Sanjay Author-X-Name-Last: Singh Author-Name: Seema Sharma Author-X-Name-First: Seema Author-X-Name-Last: Sharma Author-Name: S.R. Singh Author-X-Name-First: S.R. Author-X-Name-Last: Singh Title: Inventory model for deteriorating items with incremental holding cost under partial backlogging Abstract: The present paper deals with an inventory model for deteriorating items with dynamic demand. Shortages are allowed and partially backlogged. The demand has been considered as the function of inventory level during storage period and function of time during shortage period. Storage period is divided into <i>n</i> distinct time periods. In practice, longer storage period requires additional specialised equipment and facilities to keep the products away from deterioration. So, it is assumed that holding cost is increasing step function. The model has been discussed for <i>n</i> arbitrary distinct time periods of storage time and a numerical example has been solved for <i>n</i> = 1 and 2. The sensitivity analysis has been performed in order to examine the effect of various costs and parameters on optimal policy. Journal: Int. J. of Mathematics in Operational Research Pages: 110-126 Issue: 1 Volume: 15 Year: 2019 Keywords: inventory; holding cost; deterioration; partial backlogging. File-URL: http://www.inderscience.com/link.php?id=101615 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:1:p:110-126 Template-Type: ReDIF-Article 1.0 Author-Name: Dimitra Alexiou Author-X-Name-First: Dimitra Author-X-Name-Last: Alexiou Title: Minimising vehicle distribution duration considering service priority Abstract: A vehicle routing problem (VRP) is dealt with, where a fleet of vehicles serve (distribution/pickup) a given subset of demand locations in an urban network. A service time priority degree is given to a subset of demand locations. The aim of this paper is to find the least possible overall service time for vehicles to all the demand locations and particularly those that have a high degree of priority. The problem is dealt with in the context of graph theory and a corresponding method is proposed. The paper incorporates a numerical example of the proposed method. Journal: Int. J. of Mathematics in Operational Research Pages: 127-136 Issue: 1 Volume: 15 Year: 2019 Keywords: distribution; graph theory; vehicle routing; priority service; network. File-URL: http://www.inderscience.com/link.php?id=101616 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:1:p:127-136 Template-Type: ReDIF-Article 1.0 Author-Name: S. Jeyakumar Author-X-Name-First: S. Author-X-Name-Last: Jeyakumar Author-Name: E. Rameshkumar Author-X-Name-First: E. Author-X-Name-Last: Rameshkumar Title: A study on MX/G(a, b)/1 queue with server breakdown without interruption and controllable arrivals during multiple adaptive vacations Abstract: A single server model, after completion of a bulk service, if there is no breakdown with probability (1 &minus; ψ) and queue length (queue) &ge; 'a', then the bulk service continues, otherwise, the server performs closedown work is analysed. At the end of bulk service, if there is a breakdown occurs with probability (ψ), then the server performs renovation process. After that, if the queue is &ge; 'a', then he performs bulk service otherwise the server perform closedown work follows a vacation. After that, if the queue is less than 'a', then he takes at most 'M' vacations successively. After 'M' vacations, if the queue is still less than 'a', then he remains in the system. However, the customers enter the service station with probability 'p' (0 &le; <i>p</i> &le; 1) during multiple adaptive vacations. The probability generating function (PGF) of queue size and performance measures are obtained and cost model is developed. Journal: Int. J. of Mathematics in Operational Research Pages: 137-155 Issue: 2 Volume: 15 Year: 2019 Keywords: multiple adaptive vacation; closedown times; server breakdown; renovation times; controllable arrival; queue; bulk service; supplementary variables; dormant period; probability generating function; PGF. File-URL: http://www.inderscience.com/link.php?id=101617 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:2:p:137-155 Template-Type: ReDIF-Article 1.0 Author-Name: Amit Manocha Author-X-Name-First: Amit Author-X-Name-Last: Manocha Author-Name: Gulshan Taneja Author-X-Name-First: Gulshan Author-X-Name-Last: Taneja Author-Name: Sukhvir Singh Author-X-Name-First: Sukhvir Author-X-Name-Last: Singh Author-Name: Rahul Rishi Author-X-Name-First: Rahul Author-X-Name-Last: Rishi Title: Modelling and analysis of two-unit hot standby database system with random inspection of standby unit Abstract: Stochastic model for a two-unit hot standby database system comprising of one operative (primary unit) and one hot standby unit has been developed. The primary unit acts as production unit which is synchronised with hot standby unit through online transfer of archive redo logs. The data being saved in the primary unit gets simultaneously stored in the hot standby unit. The different modes of failure of primary database have been considered. To avoid loss of data, random inspection of the standby unit is carried out by a database administrator (DBA) to see as to whether redo log files are created/updated in standby unit or not. The repair of the failed unit and creation/updation of redo log files are also done by the DBA. The system is analysed using semi-Markov process and regenerative point technique. Mathematical expressions for various performance measures of the system have been obtained along with cost-benefit analysis of the system. Numerical analysis has been done to validate the derived results. Bounds for various parameters have also been obtained with regard to profitability of the system. Journal: Int. J. of Mathematics in Operational Research Pages: 156-180 Issue: 2 Volume: 15 Year: 2019 Keywords: database system; hot standby; random inspection; semi-Markov process; regenerative point technique; stochastic modelling; system effectiveness; cost-benefit analysis; profitability; bounds. File-URL: http://www.inderscience.com/link.php?id=101618 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:2:p:156-180 Template-Type: ReDIF-Article 1.0 Author-Name: Sonu Rajak Author-X-Name-First: Sonu Author-X-Name-Last: Rajak Author-Name: P. Parthiban Author-X-Name-First: P. Author-X-Name-Last: Parthiban Author-Name: R. Dhanalakshmi Author-X-Name-First: R. Author-X-Name-Last: Dhanalakshmi Title: A hybrid metaheuristics approach for a multi-depot vehicle routing problem with simultaneous deliveries and pickups Abstract: Multi-depot vehicle routing problem with simultaneous deliveries and pickups (MDVRPSDP) is a variant of classical vehicle routing problem (VRP), which has often encountered in real-life scenarios of transportation logistics; Where, vehicles are required to simultaneously deliver the goods and also pick-up some goods from the customers. The current scenario importance of reverse logistics activities has increased. Therefore it is necessary to determine efficient and effective vehicle routes for simultaneous delivery and pick-up activities. MDVRPSDP, which is very well-known non-deterministic polynomial-hard (NP-hard) and combinatorial optimisation (CO) problem, which requires metaheuristics to solve this type of problems. In this context, this article presents a hybrid metaheuristic which combines simulated annealing (SA), ant colony optimisation (ACO) and along with long-arc-broken removal heuristic approach for solving the MDVRPSDP. The preliminary results show that the proposed algorithm can provide good solutions. Journal: Int. J. of Mathematics in Operational Research Pages: 197-210 Issue: 2 Volume: 15 Year: 2019 Keywords: K-means clustering; vehicle routing problem; VRP; simulated annealing; ant colony optimisation; ACO; long-arc-broken removal heuristic. File-URL: http://www.inderscience.com/link.php?id=101619 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:2:p:197-210 Template-Type: ReDIF-Article 1.0 Author-Name: Mehdi Allahdadi Author-X-Name-First: Mehdi Author-X-Name-Last: Allahdadi Title: A modified two-step method for solving interval linear programming problems Abstract: In this paper, we propose a new method for solving interval linear programming (ILP) problems. For solving the ILP problems, two important items should be considered: feasibility (i.e., solutions satisfy all constraints) and optimality (i.e., solutions are optimal for at least a characteristic model). In some methods, a part of the solution space is infeasible (i.e., it violates any constraints) such as the best and worst cases method (BWC) proposed by Tong in 1994 and two-step method (TSM) proposed by Huang et al. in 1995. In some methods, the solution space is completely feasible, but is not completely optimal (i.e., some points of the solution space are not optimal) such as modified ILP method (MILP) proposed by Zhou et al. in 2009 and improved TSM (ITSM) proposed by Wang and Huang in 2014. Firstly, basis stability for the ILP problems is reviewed. Secondly, the solving methods are analysed from the point of view of the feasibility and optimality conditions. Later, a new method which modifies the TSM by using the basis stability approach is presented. This method gives a solution space that is not only completely feasible, but also completely optimal. Journal: Int. J. of Mathematics in Operational Research Pages: 181-196 Issue: 2 Volume: 15 Year: 2019 Keywords: basis stability; feasibility; interval linear programming; ILP; optimality; two-step method; TSM. File-URL: http://www.inderscience.com/link.php?id=101620 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:2:p:181-196 Template-Type: ReDIF-Article 1.0 Author-Name: Barun Khara Author-X-Name-First: Barun Author-X-Name-Last: Khara Author-Name: Jayanta Kumar Dey Author-X-Name-First: Jayanta Kumar Author-X-Name-Last: Dey Author-Name: Shyamal Kumar Mondal Author-X-Name-First: Shyamal Kumar Author-X-Name-Last: Mondal Title: Effects of product reliability dependent demand in an EPQ model considering partially imperfect production Abstract: In this article, an economic production quantity (EPQ) model with partially imperfect production system has been considered where both perfect and imperfect quality items are produced and demand of the product has been assumed as a function of selling price, reliability of the product and advertisement. Perfect quality items are ready for sale but imperfect quality items are reworked at a cost to become perfect one. Reworking cost, reliability of the product and reliability parameter of the manufacturing system can be improved by introducing the time dependent development cost and also by improving the quality of the raw material used in the production system. Under such circumstances, a profit function has been developed and maximised by optimising the reliability parameter of the manufacturing system, reliability of the product and duration of production. Finally, the model has been illustrated with some numerical examples. Journal: Int. J. of Mathematics in Operational Research Pages: 242-264 Issue: 2 Volume: 15 Year: 2019 Keywords: inventory; imperfect production; production time; reliability parameter; product reliability; development cost; rework; screening cost; raw material cost; advertisement; selling price. File-URL: http://www.inderscience.com/link.php?id=101621 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:2:p:242-264 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: Generalised linear search plan for a D-dimensional random walk target Abstract: In this paper, we present a mathematical search model that studies the generalised linear search plan for detecting a d-dimensional random walk target. The target will meet one of the searchers where each searcher starts its motion from any point rather than the origin on <i>n</i>-disjoint real lines in &Ropf;<SUP align="right"><SMALL><i>n</i></SMALL></SUP>. Rather than, finding the conditions that show the finiteness of this search plan, we study the existence of the optimal search plan that minimises the expected value of the first meeting time between one of the searchers and the target. Journal: Int. J. of Mathematics in Operational Research Pages: 211-241 Issue: 2 Volume: 15 Year: 2019 Keywords: linear search method; d-dimensional random walk; finite search plan; optimal search plan; semi continuous mapping. File-URL: http://www.inderscience.com/link.php?id=101622 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:2:p:211-241 Template-Type: ReDIF-Article 1.0 Author-Name: Sapan Kumar Das Author-X-Name-First: Sapan Kumar Author-X-Name-Last: Das Author-Name: T. Mandal Author-X-Name-First: T. Author-X-Name-Last: Mandal Author-Name: Diptiranjan Behera Author-X-Name-First: Diptiranjan Author-X-Name-Last: Behera Title: A new approach for solving fully fuzzy linear programming problem Abstract: This paper presents the limitations of citeku for solving a fully fuzzy linear programming (FFLP) problem. And accordingly to overcome these limitations a new method has been proposed by using the ranking function. We have considered a FFLP problem with mixed constraints where decision variables are represented by non-negative fuzzy numbers. Triangular convex normalised fuzzy sets are considered for the analysis. To illustrate the applicability and efficiency of the proposed method various numerical examples have been solved and obtained results are discussed. Journal: Int. J. of Mathematics in Operational Research Pages: 296-309 Issue: 3 Volume: 15 Year: 2019 Keywords: fully fuzzy linear programming; fuzzy optimal solution; triangular fuzzy numbers; ranking function. File-URL: http://www.inderscience.com/link.php?id=102074 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:3:p:296-309 Template-Type: ReDIF-Article 1.0 Author-Name: C. Suganya Author-X-Name-First: C. Author-X-Name-Last: Suganya Author-Name: B. Sivakumar Author-X-Name-First: B. Author-X-Name-Last: Sivakumar Title: MAP/PH(1), PH(2)/2 finite retrial inventory system with service facility, multiple vacations for servers Abstract: In this paper, we consider a retrial (<i>s</i>, <i>S</i>) inventory system with multiple server vacations for two heterogeneous servers. We have assumed that the customers arrive according to a Markovian arrival process and two parallel servers who provide heterogeneous phase type services to customers. The lead times for the orders are assumed to have independent and identical exponential distributions. The vacation times of both servers are assumed to be independent and identically distributed exponential random variables. The arriving customer who finds both servers are busy or both servers are on vacation, joins an orbit of finite size. These orbiting customers retry for their demand after a random time, which is assumed to be exponential distribution. Some important performance measures are obtained and the optimality of an expected total cost rate is shown through numerical illustration. Journal: Int. J. of Mathematics in Operational Research Pages: 265-295 Issue: 3 Volume: 15 Year: 2019 Keywords: service facility; heterogeneous servers; multiple vacations; retrial customers. File-URL: http://www.inderscience.com/link.php?id=102075 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:3:p:265-295 Template-Type: ReDIF-Article 1.0 Author-Name: Chanaka Edirisinghe Author-X-Name-First: Chanaka Author-X-Name-Last: Edirisinghe Author-Name: William Ziemba Author-X-Name-First: William Author-X-Name-Last: Ziemba Title: A boundary-point LP solution method and its application to dense linear programs Abstract: This paper presents a linear programming solution method that generates a sequence of boundary-points belonging to faces of the feasible polyhedron. The method is based on a steepest descent search by iteratively optimising over a two-dimensional cross section of the polyhedron. It differs from extreme point algorithms such as the simplex method in that optimality is detected by identifying an optimal face of the polyhedron which is not necessarily an extreme point. It also differs from the polynomial-time methods such as the ellipsoid algorithm or projective scaling method that avoids the boundary of the feasible polyhedron. Limited computational analysis with an experimental code of the method, EZLP, indicates that our method performs quite well in total solution time when the number of variables and the density of the constraint matrix increase. Journal: Int. J. of Mathematics in Operational Research Pages: 310-337 Issue: 3 Volume: 15 Year: 2019 Keywords: linear programming; nonlinear programming; steepest descent; orthogonal projections. File-URL: http://www.inderscience.com/link.php?id=102076 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:3:p:310-337 Template-Type: ReDIF-Article 1.0 Author-Name: Lahna Idres Author-X-Name-First: Lahna Author-X-Name-Last: Idres Author-Name: Mohammed Said Radjef Author-X-Name-First: Mohammed Said Author-X-Name-Last: Radjef Title: The efficiency of greedy best response algorithm in road traffic assignment Abstract: In this work, we investigate the problem of the integer road traffic assignment. So, we model the interaction among the road users sharing the same origin-destination pair, as a symmetric network congestion game. We focus on Rosenthal's results to guarantee the existence of a pure Nash equilibrium (PNE). Then, we study the behaviour of an algorithm based on greedy best response (GBR) in finding PNE. In previous studies, the efficiency of GBR to compute a PNE of a symmetric network congestion game in series-parallel networks is proved. In our work, another approach is used to demonstrate its efficiency in more general networks. It is shown that the non-series parallel networks can be classed into two types. The conditions that make GBR succeeds for each type is then drawn. The advantage of GBR-algorithm is that provides a better approximation of the equilibrate assignment, since it is integer. Journal: Int. J. of Mathematics in Operational Research Pages: 338-363 Issue: 3 Volume: 15 Year: 2019 Keywords: road traffic assignment; congestion game; Nash equilibrium; GBR algorithm. File-URL: http://www.inderscience.com/link.php?id=102077 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:3:p:338-363 Template-Type: ReDIF-Article 1.0 Author-Name: P. Malini Author-X-Name-First: P. Author-X-Name-Last: Malini Title: A new ranking technique on heptagonal fuzzy numbers to solve fuzzy transportation problem Abstract: In this work, a general fuzzy transportation problem model is discussed and proposed a new ranking procedure to the heptagonal fuzzy numbers using which convert any fuzzy valued transportation problem to a crisp valued transportation problem which then could be solved using the MODI method. The proposed method serves as an efficient method in ranking heptagonal fuzzy numbers which is illustrated through a numerical example. The purpose of this paper is to give a new ranking index to rank fuzzy numbers effectively. Fuzzy numbers cannot be easily ordered as ordinary real numbers. Several proposals have addressed this problem, each with some drawbacks and limitations. This paper renounces to the idea of finding a universal ordering method for fuzzy numbers. Journal: Int. J. of Mathematics in Operational Research Pages: 364-371 Issue: 3 Volume: 15 Year: 2019 Keywords: heptagonal fuzzy numbers; fuzzy transportation problem; fuzzy programming; nonlinear programming. File-URL: http://www.inderscience.com/link.php?id=102078 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:3:p:364-371 Template-Type: ReDIF-Article 1.0 Author-Name: Jalil Heidary Dahooie Author-X-Name-First: Jalil Heidary Author-X-Name-Last: Dahooie Author-Name: Navid Mohammadi Author-X-Name-First: Navid Author-X-Name-Last: Mohammadi Author-Name: Amir Salar Vanaki Author-X-Name-First: Amir Salar Author-X-Name-Last: Vanaki Title: Using a multi-criteria decision making approach to select the optimal freeway rout (case study: Isfahan-Shiraz Freeway) Abstract: Road construction problems are one of the important factors in countries. The effects of multiple parameters on the decision making process to determine the optimal route have made this choice a specialised issue for decision-makers. In this regard, this paper aims to select the optimal route for Isfahan-Shiraz freeway using MADM approaches. For this purpose, in order to weight and select the optimal route, the extended dynamic fuzzy GRA method is used. The results show that road longevity, views of the NGOs, route integrity and ease of tracking are identified as the highest-weighted criteria in the prioritisation of the route variant. To evaluate the validity of the results of the GRA method, the problem is examined by using the, COPRAS-IVIF, ARAS-IVTF, WASPAS-IVIF, TOPSIS-IVIF and MULTIMOORA-IVIF methods. In addition, route 3 that takes priority over others is also chosen, in practice, as the main basis for the work. Journal: Int. J. of Mathematics in Operational Research Pages: 372-394 Issue: 3 Volume: 15 Year: 2019 Keywords: variant route selection; freeway; multi attribute decision making; MADM; dynamic fuzzy GRA. File-URL: http://www.inderscience.com/link.php?id=102079 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:3:p:372-394 Template-Type: ReDIF-Article 1.0 Author-Name: Minakshi Parida Author-X-Name-First: Minakshi Author-X-Name-Last: Parida Author-Name: Sunita Chand Author-X-Name-First: Sunita Author-X-Name-Last: Chand Title: On differentiable harmonic univex fuzzy mappings and its applications to fuzzy mathematical programming problem Abstract: In this paper, harmonic preunivex (H-preunivex) and harmonic preunicave (H-preunicave) fuzzy mappings have been introduced and several interesting results have been obtained related to generalised convexity. By using the concept of differentiability with H-preunivex and H-preunicave fuzzy mappings, harmonic univex (H-univex) and harmonic unicave (Hunicave) fuzzy mappings have been obtained respectively. Furthermore, H-univex and pseudo H-univex fuzzy mappings have been applied to study the sufficient optimality conditions and the duality results for Harmonic univex fuzzy programming problem (HUFP). Moreover, KKT conditions for the HUFP have been studied by using the H-univex fuzzy mappings. Suitable examples have been given to illustrate the results. Journal: Int. J. of Mathematics in Operational Research Pages: 464-497 Issue: 4 Volume: 15 Year: 2019 Keywords: fuzzy optimisation; H-preunivex; H-preunicave; H-univex; H-unicave; fuzzy mappings; sufficient optimality conditions; duality results. File-URL: http://www.inderscience.com/link.php?id=102992 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:4:p:464-497 Template-Type: ReDIF-Article 1.0 Author-Name: Abhijit Baidya Author-X-Name-First: Abhijit Author-X-Name-Last: Baidya Author-Name: Uttam Kumar Bera Author-X-Name-First: Uttam Kumar Author-X-Name-Last: Bera Title: Solid transportation problem under fully fuzzy environment Abstract: Transportation policy seeks to improve agency freight and cargo management and enhance sustainable, efficient and effective transportation operations. In this paper, the profit maximisation solid transportation problem under fully fuzzy environment is formulated. In this model formulation the transportation parameters and decision variables both are considered as fuzzy in nature. Also, an additional new constraint on the complete budget at each destination is imposed. Five new approaches are proposed to defuzzify the fully fuzzy model. The nearest interval approximation is used to convert the fully fuzzy model into its equivalent interval form. The interactive fuzzy satisfying technique and different interval approaches are used to determine the crisp equivalent of the objective function and constraints of the proposed model. The reduced deterministic model was solved using generalised reduced gradient techniques (GRG technique). A numerical example is provided to illustrate the model and methodology and finally, the obtained results are compared. Journal: Int. J. of Mathematics in Operational Research Pages: 498-539 Issue: 4 Volume: 15 Year: 2019 Keywords: fully fuzzy solid transportation problem; complete budget constraint; interval approaches; nearest interval approximation; interactive fuzzy satisfying technique; IFST. File-URL: http://www.inderscience.com/link.php?id=102997 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:4:p:498-539 Template-Type: ReDIF-Article 1.0 Author-Name: Paúl Sebastián Dávila Aldás Author-X-Name-First: Paúl Sebastián Dávila Author-X-Name-Last: Aldás Author-Name: Jessica Constante Author-X-Name-First: Jessica Author-X-Name-Last: Constante Author-Name: Gabriela Chávez Tapia Author-X-Name-First: Gabriela Chávez Author-X-Name-Last: Tapia Author-Name: Javier Martínez-Gómez Author-X-Name-First: Javier Author-X-Name-Last: Martínez-Gómez Title: Monohull ship hydrodynamic simulation using CFD Abstract: This research analyses the performance of a ship monohull at Galapagos real conditions using ANSYS FLUENT. In order to achieve these analyses, tide charts at Santa Cruz Island coast in Galapagos Islands were considered, since similar motorboats provide services as taxi boats in this area. These analyses were made in order to validate ships behaviour existing in Galapagos Islands. In addition, through simulation is not necessary to build these ships, in a way to obtain same results using less economic and technical resources. The hydrodynamic analysis of a monohull was simulated in static and dynamic conditions. Static analysis considers water and air flows hitting the boat bow which is resting (anchored boat). While dynamic analysis considers both the boat and water flow speed (sailing boat). Main results were: static and dynamic pressures, water height achieved by flow and ship speed variation, turbulence intensity, and simulation convergence residuals. Journal: Int. J. of Mathematics in Operational Research Pages: 417-433 Issue: 4 Volume: 15 Year: 2019 Keywords: monohull; hydrodynamics simulation; ANSYS-FLUENT; computational fluid dynamics; CFD. File-URL: http://www.inderscience.com/link.php?id=103000 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:4:p:417-433 Template-Type: ReDIF-Article 1.0 Author-Name: Arindam Garai Author-X-Name-First: Arindam Author-X-Name-Last: Garai Author-Name: Bappa Mondal Author-X-Name-First: Bappa Author-X-Name-Last: Mondal Author-Name: Tapan Kumar Roy Author-X-Name-First: Tapan Kumar Author-X-Name-Last: Roy Title: Optimisation of multi-objective commercial bank balance sheet management model: a parametric T-set approach Abstract: In this article, we consider optimisation of multi-objective model with fuzzy coefficients in imprecise environment. In 2016, we introduced T-set to supersede fuzzy set for representing impreciseness. It followed our observation that some constraints of existing classical fuzzy optimisation method compel membership values of fuzzy objective functions and constraints to fall in range between zero and one. So we cannot always attain most preferable Pareto optimal solution to it. Again existing constraints in this method sometimes show models as infeasible. Here we introduce parametric T-set. Next we consider multi-objective optimisation model with fuzzy cost coefficients and present general algorithm to arrive at parametric Pareto optimal solution to it. In numerical application, we illustrate usefulness of proposed algorithm by considering commercial bank balance sheet management model with fuzzy cost coefficients in parametric T-environment. Also we perform sensitivity analysis of parameters and present key managerial insights. Finally we draw conclusions. Journal: Int. J. of Mathematics in Operational Research Pages: 395-416 Issue: 4 Volume: 15 Year: 2019 Keywords: commercial bank balance sheet management; fuzzy coefficients; multi-objective optimisation; Pareto optimal solution; parametric T-characteristic function; parametric T-set. File-URL: http://www.inderscience.com/link.php?id=103001 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:4:p:395-416 Template-Type: ReDIF-Article 1.0 Author-Name: S.M. Abul Kalam Azad Author-X-Name-First: S.M. Abul Kalam Author-X-Name-Last: Azad Author-Name: M. Kamrul Hasan Author-X-Name-First: M. Kamrul Author-X-Name-Last: Hasan Title: An effective algorithm to solve cost minimising transportation problem Abstract: The developed algorithm in this article provides an initial basic feasible solution (IBFS) of the transportation problem (TP) of the linear programming problem. The proposed method, which involves fewer calculations and fewer steps or iterations, is able to provide a better approximate solution to the TP than classical methods, especially Vogel's approximation method (VAM). This method is also easier and more effective than some recent methods to solve TPs, which were introduced by various researches. This article illustrates the simplicity and effectiveness of the developed algorithm by providing a good number of examples. Journal: Int. J. of Mathematics in Operational Research Pages: 434-445 Issue: 4 Volume: 15 Year: 2019 Keywords: initial basic feasible solution; IBFS; transportation problem; TP; Vogel's approximation method; VAM; transportation table; cost unit. File-URL: http://www.inderscience.com/link.php?id=103005 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:4:p:434-445 Template-Type: ReDIF-Article 1.0 Author-Name: Anu Gupta Aggarwal Author-X-Name-First: Anu Gupta Author-X-Name-Last: Aggarwal Author-Name: Neha Gandhi Author-X-Name-First: Neha Author-X-Name-Last: Gandhi Author-Name: Vibha Verma Author-X-Name-First: Vibha Author-X-Name-Last: Verma Author-Name: Abhishek Tandon Author-X-Name-First: Abhishek Author-X-Name-Last: Tandon Title: Multi-release software reliability growth assessment: an approach incorporating fault reduction factor and imperfect debugging Abstract: In the last few decades, a plenty of software reliability growth models with diverse parameters have been formulated and proposed to assess software trustworthiness. Fault reduction factor (FRF) is one such significant factor which has been incorporated in numerous reliability modelling researches in past and results have proved its importance on reliability growth phenomenon. To keep pace with rising demands of the market, software development firms keep upgrading their products in terms of new features and by providing rectification of previously reported defects. In this paper, an SRGM based on NHPP integrating imperfect debugging and time-variable FRF is proposed for multi-release software systems. The model is then tested on the failure datasets of multiple releases of Tandem Computers and Firefox OSS. The experimental results for each release are compared with their corresponding perfect debugging model. Results illustrate that the proposed model fits the failure data well, outperforming perfect debugging model. Journal: Int. J. of Mathematics in Operational Research Pages: 446-463 Issue: 4 Volume: 15 Year: 2019 Keywords: software reliability growth model; fault reduction factor; FRF; least square estimation; multi-release; imperfect debugging. File-URL: http://www.inderscience.com/link.php?id=103006 File-Format: text/html File-Restriction: Access to full text is restricted to subscribers. Handle: RePEc:ids:ijmore:v:15:y:2019:i:4:p:446-463