Pub Date : 2019-07-08DOI: 10.1504/IJMOR.2019.10022360
Umut Besikci, Ümit Bilge, G. Ulusoy
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.
{"title":"Resource portfolio problem under relaxed resource dedication policy in multi-mode multi-project scheduling","authors":"Umut Besikci, Ümit Bilge, G. Ulusoy","doi":"10.1504/IJMOR.2019.10022360","DOIUrl":"https://doi.org/10.1504/IJMOR.2019.10022360","url":null,"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.","PeriodicalId":306451,"journal":{"name":"Int. J. Math. Oper. Res.","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132049936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-02DOI: 10.1504/IJMOR.2019.10022361
Y. Sarada, R. Shenbagam
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.
{"title":"On phase type arithmetico-geometric process and its application to deteriorating systems with warranty","authors":"Y. Sarada, R. Shenbagam","doi":"10.1504/IJMOR.2019.10022361","DOIUrl":"https://doi.org/10.1504/IJMOR.2019.10022361","url":null,"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.","PeriodicalId":306451,"journal":{"name":"Int. J. Math. Oper. Res.","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130547986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-02DOI: 10.1504/IJMOR.2019.10022356
Phani Bushan Rao Peddi
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.
{"title":"Evaluating fuzzy risk based on a new method of ranking fuzzy numbers using centroid of centroids","authors":"Phani Bushan Rao Peddi","doi":"10.1504/IJMOR.2019.10022356","DOIUrl":"https://doi.org/10.1504/IJMOR.2019.10022356","url":null,"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.","PeriodicalId":306451,"journal":{"name":"Int. J. Math. Oper. Res.","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124695353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-02DOI: 10.1504/IJMOR.2019.10022358
G. Villacreses, Javier Martinez Gomez, Paola Quintana, C. RicardoA.Narváez
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.
{"title":"Geolocation of electric bikes recharging stations: City of Quito study case","authors":"G. Villacreses, Javier Martinez Gomez, Paola Quintana, C. RicardoA.Narváez","doi":"10.1504/IJMOR.2019.10022358","DOIUrl":"https://doi.org/10.1504/IJMOR.2019.10022358","url":null,"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.","PeriodicalId":306451,"journal":{"name":"Int. J. Math. Oper. Res.","volume":"640 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115110389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-02DOI: 10.1504/IJMOR.2019.10022357
S. Stephen, D. David, A. Ajay
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.
{"title":"Design optimisation of cost of the pressure vessel through MATLAB and simulation through ANSYS","authors":"S. Stephen, D. David, A. Ajay","doi":"10.1504/IJMOR.2019.10022357","DOIUrl":"https://doi.org/10.1504/IJMOR.2019.10022357","url":null,"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.","PeriodicalId":306451,"journal":{"name":"Int. J. Math. Oper. Res.","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134243697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-02DOI: 10.1504/IJMOR.2019.10022359
C. Singh, S. Kaur, Madhu Jain
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.
{"title":"Analysis of bulk queue with additional optional service, vacation and unreliable server","authors":"C. Singh, S. Kaur, Madhu Jain","doi":"10.1504/IJMOR.2019.10022359","DOIUrl":"https://doi.org/10.1504/IJMOR.2019.10022359","url":null,"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.","PeriodicalId":306451,"journal":{"name":"Int. J. Math. Oper. Res.","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127136433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-29DOI: 10.1504/IJMOR.2019.10020787
Gera Workie Woubante, A. Alemu, S. Gebrehiwot
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 ‒ 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.
{"title":"Ensure optimum profit using linear programming a product-mix of textile manufacturing companies","authors":"Gera Workie Woubante, A. Alemu, S. Gebrehiwot","doi":"10.1504/IJMOR.2019.10020787","DOIUrl":"https://doi.org/10.1504/IJMOR.2019.10020787","url":null,"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 ‒ 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.","PeriodicalId":306451,"journal":{"name":"Int. J. Math. Oper. Res.","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133298608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-24DOI: 10.1504/IJMOR.2019.10020786
S. Saha, Nabendu Sen
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.
{"title":"An inventory model for deteriorating items with time and price dependent demand and shortages under the effect of inflation","authors":"S. Saha, Nabendu Sen","doi":"10.1504/IJMOR.2019.10020786","DOIUrl":"https://doi.org/10.1504/IJMOR.2019.10020786","url":null,"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.","PeriodicalId":306451,"journal":{"name":"Int. J. Math. Oper. Res.","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115418239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-24DOI: 10.1504/IJMOR.2019.10020785
R. Uthayakumar, M. G. Kumar
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.
{"title":"Single-vendor multi-buyer integrated inventory system for multi-item","authors":"R. Uthayakumar, M. G. Kumar","doi":"10.1504/IJMOR.2019.10020785","DOIUrl":"https://doi.org/10.1504/IJMOR.2019.10020785","url":null,"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.","PeriodicalId":306451,"journal":{"name":"Int. J. Math. Oper. Res.","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115006724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-24DOI: 10.1504/IJMOR.2019.10020782
G. K. Gupta, A. Banerjee
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.
{"title":"Steady state analysis of system size-based balking in M/Mb/1 queue","authors":"G. K. Gupta, A. Banerjee","doi":"10.1504/IJMOR.2019.10020782","DOIUrl":"https://doi.org/10.1504/IJMOR.2019.10020782","url":null,"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.","PeriodicalId":306451,"journal":{"name":"Int. J. Math. Oper. Res.","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115022413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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