Dr. Bikash Koli Dey | Hongik University (original) (raw)
Papers by Dr. Bikash Koli Dey
RAIRO - Operations Research, 2022
With the advancement of technologies, industries tries to adopt the advantages of the technology.... more With the advancement of technologies, industries tries to adopt the advantages of the technology. Customers are busy in their daily life, and the online platform is the best option for retail, whereas traditional customers still prefer to visit the retail shop. Few customers choose the product online but buy it online or vice-versa. Owing to all those circumstances, current study focuses on an intelligent dual channel (online-to-offine) strategy in industry to arrange the optimal services for customers. The selling price of the product vary with different channel, which helps to determine the demand of product for entire supply chain. Two important factors, backorder and lead-time are examined precisely through marginal value which helps to arrange optimal service and calculate the exact profit. The profit for a centralized and decentralized case are computed for both the players. Some propositions are developed to prove the global optimality. Numerical results prove that a centrali...
Sustainability, 2021
Every industry always tries to provide the best service to its consumers. To provide better servi... more Every industry always tries to provide the best service to its consumers. To provide better service to the consumer and optimize profit, a sustainable online-to-offline retailing strategy is proposed in this current study. Both online and offline systems are considered here, i.e., to provide the best service, the industry sells its products online and offline. Due to the consideration of online and offline systems, the selling price of the products is also different for different modes, and the demand for a particular product is the combined demand of online demand and offline demand, which depend on the selling price of the product. Moreover, the exact lead time and exact backorder are calculated to obtain the system’s exact cost or profit, which directly improves the system’s service. Different investments are incorporated to optimize the total system profit. A distribution-free approach is utilized to solve this model. Numerical examples are provided to prove the applicability of...
Computers & Industrial Engineering
Abstract This paper investigates an impact of random defective rates in an imperfect production s... more Abstract This paper investigates an impact of random defective rates in an imperfect production system with multiple products and planned backorders in a single-stage production system. The purpose of this study is to control a single-stage cleaner production system with a random defective rate for multiple products. Considering these, the model becomes a non-linear constraint problem. Based on different distribution functions of random defective rates, to eliminate the defective items from the system, five special cases for effective system management are considered. A non-linear optimization technique is utilized to solve the model and obtain the global optimum solution of cleaner production system with multiple products and a global optimum solution. Numerical examples, graphical representations, and sensitivity analysis are given to illustrate the model. Numerical studies prove that the cost related with a Chi-square distribution gives the least cost and cost related with a beta distribution gives the maximum cost, whereas the literature shows a triangular distribution gives the minimum cost.
Computers & Industrial Engineering
Mathematics
This model investigates the variable production cost for a production house; under a two-echelon ... more This model investigates the variable production cost for a production house; under a two-echelon supply chain management where a single vendor and multi-retailers are involved. This production system goes through a long run system and generates an out-of-control state due to different issues and produces defective items. This model considers the reduction of the defective rate and setup cost through investment. A discrete investment for setup cost reduction and a continuous investment is considered to reduce the defective rate and to increase the quality of products. Setup and processing time are dependent on lead time in this model. The model is solved analytically to find the optimal values of the production rate, safety factors, optimum quantity, lead time length, investment for setup cost reduction, and the probability of the production process going out-of-control. An efficient algorithm is constructed to find the optimal solution numerically and sensitivity analysis is given t...
Mathematics
This study explains about a serial smart production system where a single-type of product is prod... more This study explains about a serial smart production system where a single-type of product is produced. This system uses an unequally sized batch policy in subsequent stages. The setup cost is not always deterministic, it can be controllable and reduced by increasing the capital investment cost, and that the production rates in the system may vary within given limits across batches of shipments. Furthermore, as imperfect items are produced in long-run system, to clean the imperfectness autonomation policy is adopted for inspection, which make the process smarter. The shipment lot sizes of the deliveries are unequal and variable. In long-run production system, defective items are produced in “out-of-control” state. In this model, the defect rate is random with a uniform distribution which is clean from the system by autonomation. In addition, in the remanufacturing process, it is assuming that all defective products are repaired, and no defective products are scrapped. The main theme ...
International Journal of Services Operations and Informatics
Expert Systems with Applications
Mathematics
The proposed model focuses on an imperfect production process (IPP) in which, during long-term pr... more The proposed model focuses on an imperfect production process (IPP) in which, during long-term production, the system may change to an “out-of-control” state from an “in-control” state and produce some imperfect products because of a long production run length. Brand image and industry reputation are affected by product defectiveness. To increase the profit of any industry and improve reputation and brand image, inspection of the production system is required. However, this inspection is subjected to human error, which negatively affects the assessment of production systems. Herein, an error-free inspection is performed with the help of an autonomation policy, in which each product is inspected via a machine instead of a human, facilitating an error-free inspection and converting the production system to a smart production system. Moreover, in reality, product demand cannot always be constant. Therefore, in this model, a selling-price-dependent demand is considered along with a vari...
International Journal of Production Research
RAIRO - Operations Research
The concept of advanced sustainable inventory manage- ment, where demand pattern stock level and ... more The concept of advanced sustainable inventory manage- ment, where demand pattern stock level and advertising dependent under trade-credit policy is taking account in this present study. Opti- mal credit period and cycle time are the main objective of this advanced system. A developed solution methodology is derived to show the exis- tence of global optimality under optimum credit period and cycle time. The main concern of this advanced system is to maximize the annual total system pro t of retailer with nite replenishment rate. Numerical illustration are carry forward for di erent cases to prove the stainabil- ity along with real impact of this model. Sensitive analysis for the key parameters is discussed in sensitivity analysis section along with some real \managerial insights".
RAIRO - Operations Research
In this study one obtained the optimal decision of a retailer for the replenishment rate with sel... more In this study one obtained the optimal decision of a retailer for the replenishment rate with selling-price and credit-period dependent demand to maximize the profit. A time-varying deterioration rate was considered for those products. A credit-period was offered by the retailer to the end customer to settle the whole payments. The aim of the model was to obtain the maximum profit for the retailer based model. A solution methodology with an algorithm was used to obtain the global optimum profit. An illustrative numerical example was given to test the practical applicability of the model. Numerical study indicated that the profit was at a maximum when the permissible delay-period for payment offered by the suppliers was lies between the permissible delay-time, and the cycle time, offered by the retailer.
RAIRO - Operations Research
This paper develops a sustainable integrated inventory model for maximizing profit with a control... more This paper develops a sustainable integrated inventory model for maximizing profit with a controllable lead time, discrete setup cost reduction, and consideration of environmental issues. Contrary to the available literature, this paper considers a discrete setup cost for the vendor, thus making the integrated model sustainable. The customer’s demand is assumed to be selling-price dependent to increase the number of sales, and the lead time demand follows a Poisson distribution. The integrated model is used to optimized the total shipment number, volume of shipments, safety factor, investments, selling-price, and probability of moving between the “in-control” to “out-of-control” states. An algorithm is developed to obtain the numerical results. Numerical examples and sensitivity analyses are given to illustrate the model.
RAIRO - Operations Research
Cost reduction for setup and improvement of processes quality are the main target of this researc... more Cost reduction for setup and improvement of processes quality are the main target of this research along with free minimal repair warranty for an imperfect production System. This paper deals with the effect of setup cost reduction and process quality improvement on the optimal production cycle time for an imperfect production process with free product minimal repair warranty. Here the production system is subject to a random breakdown from an controlled system to an out-of-control state. Shortages are fully backlogged. The main target to minimize the total cost by simultaneously optimizing the production run time, setup cost, and process quality. A solution algorithm with some numerical experiments are provided such as the proposed model can illustrate briefly. Sensitivity analysis section is decorated for the optimal solution of the model with respect to major cost parameters of the system are carried out, and the implications of the analysis are discussed.
Mathematics
The present study focuses on a single-vendor, single-buyer supply chain model for a single type o... more The present study focuses on a single-vendor, single-buyer supply chain model for a single type of product with upgraded service provided to the buyer by the vendor. Vendors often increase their profit by providing a lower quality of a particular product. In this study, an advanced supply chain model is developed to increase service in the presence of an unreliable vendor and an online-to-offline (O2O) channeling system. The vendor provides lower quality items to the customer, even though they had committed to providing a certain quality product, in order to increase their profit. For more realistic results, demand is considered to be price-, quality-, and service-dependent. To advertise and sell the products, the manufacturer uses an online system, which the buyer also uses to choose and order the product, where the particular product is delivered to the customer by a third (offline) party; that is, the concept of an O2O retail channel is adopted to improve the service level of the...
For quality improvement purposes often times, a manufacturing unit has to change certain parts of... more For quality improvement purposes often times, a manufacturing unit has to change certain parts of equipment. Any such changes in the assembly line manufacturing system or production process involves a cost known as the setup cost. Minimizing the setup cost and improving the product quality is of prime importance in today's competitive business arena. This paper develops the effects of setup cost reduction and quality improvement in a two-echelon supply chain model with deterioration. The objective is to minimize the total cost of the entire supply chain model (SCM) by simultaneously optimizing setup cost, process quality, number of deliveries, and lot size. Numerical examples are provided to illustrate the model. 2010 Mathematics Subject Classification. Primary: 58F15, 58F17; Secondary: 53C35.
RAIRO - Operations Research, 2022
With the advancement of technologies, industries tries to adopt the advantages of the technology.... more With the advancement of technologies, industries tries to adopt the advantages of the technology. Customers are busy in their daily life, and the online platform is the best option for retail, whereas traditional customers still prefer to visit the retail shop. Few customers choose the product online but buy it online or vice-versa. Owing to all those circumstances, current study focuses on an intelligent dual channel (online-to-offine) strategy in industry to arrange the optimal services for customers. The selling price of the product vary with different channel, which helps to determine the demand of product for entire supply chain. Two important factors, backorder and lead-time are examined precisely through marginal value which helps to arrange optimal service and calculate the exact profit. The profit for a centralized and decentralized case are computed for both the players. Some propositions are developed to prove the global optimality. Numerical results prove that a centrali...
Sustainability, 2021
Every industry always tries to provide the best service to its consumers. To provide better servi... more Every industry always tries to provide the best service to its consumers. To provide better service to the consumer and optimize profit, a sustainable online-to-offline retailing strategy is proposed in this current study. Both online and offline systems are considered here, i.e., to provide the best service, the industry sells its products online and offline. Due to the consideration of online and offline systems, the selling price of the products is also different for different modes, and the demand for a particular product is the combined demand of online demand and offline demand, which depend on the selling price of the product. Moreover, the exact lead time and exact backorder are calculated to obtain the system’s exact cost or profit, which directly improves the system’s service. Different investments are incorporated to optimize the total system profit. A distribution-free approach is utilized to solve this model. Numerical examples are provided to prove the applicability of...
Computers & Industrial Engineering
Abstract This paper investigates an impact of random defective rates in an imperfect production s... more Abstract This paper investigates an impact of random defective rates in an imperfect production system with multiple products and planned backorders in a single-stage production system. The purpose of this study is to control a single-stage cleaner production system with a random defective rate for multiple products. Considering these, the model becomes a non-linear constraint problem. Based on different distribution functions of random defective rates, to eliminate the defective items from the system, five special cases for effective system management are considered. A non-linear optimization technique is utilized to solve the model and obtain the global optimum solution of cleaner production system with multiple products and a global optimum solution. Numerical examples, graphical representations, and sensitivity analysis are given to illustrate the model. Numerical studies prove that the cost related with a Chi-square distribution gives the least cost and cost related with a beta distribution gives the maximum cost, whereas the literature shows a triangular distribution gives the minimum cost.
Computers & Industrial Engineering
Mathematics
This model investigates the variable production cost for a production house; under a two-echelon ... more This model investigates the variable production cost for a production house; under a two-echelon supply chain management where a single vendor and multi-retailers are involved. This production system goes through a long run system and generates an out-of-control state due to different issues and produces defective items. This model considers the reduction of the defective rate and setup cost through investment. A discrete investment for setup cost reduction and a continuous investment is considered to reduce the defective rate and to increase the quality of products. Setup and processing time are dependent on lead time in this model. The model is solved analytically to find the optimal values of the production rate, safety factors, optimum quantity, lead time length, investment for setup cost reduction, and the probability of the production process going out-of-control. An efficient algorithm is constructed to find the optimal solution numerically and sensitivity analysis is given t...
Mathematics
This study explains about a serial smart production system where a single-type of product is prod... more This study explains about a serial smart production system where a single-type of product is produced. This system uses an unequally sized batch policy in subsequent stages. The setup cost is not always deterministic, it can be controllable and reduced by increasing the capital investment cost, and that the production rates in the system may vary within given limits across batches of shipments. Furthermore, as imperfect items are produced in long-run system, to clean the imperfectness autonomation policy is adopted for inspection, which make the process smarter. The shipment lot sizes of the deliveries are unequal and variable. In long-run production system, defective items are produced in “out-of-control” state. In this model, the defect rate is random with a uniform distribution which is clean from the system by autonomation. In addition, in the remanufacturing process, it is assuming that all defective products are repaired, and no defective products are scrapped. The main theme ...
International Journal of Services Operations and Informatics
Expert Systems with Applications
Mathematics
The proposed model focuses on an imperfect production process (IPP) in which, during long-term pr... more The proposed model focuses on an imperfect production process (IPP) in which, during long-term production, the system may change to an “out-of-control” state from an “in-control” state and produce some imperfect products because of a long production run length. Brand image and industry reputation are affected by product defectiveness. To increase the profit of any industry and improve reputation and brand image, inspection of the production system is required. However, this inspection is subjected to human error, which negatively affects the assessment of production systems. Herein, an error-free inspection is performed with the help of an autonomation policy, in which each product is inspected via a machine instead of a human, facilitating an error-free inspection and converting the production system to a smart production system. Moreover, in reality, product demand cannot always be constant. Therefore, in this model, a selling-price-dependent demand is considered along with a vari...
International Journal of Production Research
RAIRO - Operations Research
The concept of advanced sustainable inventory manage- ment, where demand pattern stock level and ... more The concept of advanced sustainable inventory manage- ment, where demand pattern stock level and advertising dependent under trade-credit policy is taking account in this present study. Opti- mal credit period and cycle time are the main objective of this advanced system. A developed solution methodology is derived to show the exis- tence of global optimality under optimum credit period and cycle time. The main concern of this advanced system is to maximize the annual total system pro t of retailer with nite replenishment rate. Numerical illustration are carry forward for di erent cases to prove the stainabil- ity along with real impact of this model. Sensitive analysis for the key parameters is discussed in sensitivity analysis section along with some real \managerial insights".
RAIRO - Operations Research
In this study one obtained the optimal decision of a retailer for the replenishment rate with sel... more In this study one obtained the optimal decision of a retailer for the replenishment rate with selling-price and credit-period dependent demand to maximize the profit. A time-varying deterioration rate was considered for those products. A credit-period was offered by the retailer to the end customer to settle the whole payments. The aim of the model was to obtain the maximum profit for the retailer based model. A solution methodology with an algorithm was used to obtain the global optimum profit. An illustrative numerical example was given to test the practical applicability of the model. Numerical study indicated that the profit was at a maximum when the permissible delay-period for payment offered by the suppliers was lies between the permissible delay-time, and the cycle time, offered by the retailer.
RAIRO - Operations Research
This paper develops a sustainable integrated inventory model for maximizing profit with a control... more This paper develops a sustainable integrated inventory model for maximizing profit with a controllable lead time, discrete setup cost reduction, and consideration of environmental issues. Contrary to the available literature, this paper considers a discrete setup cost for the vendor, thus making the integrated model sustainable. The customer’s demand is assumed to be selling-price dependent to increase the number of sales, and the lead time demand follows a Poisson distribution. The integrated model is used to optimized the total shipment number, volume of shipments, safety factor, investments, selling-price, and probability of moving between the “in-control” to “out-of-control” states. An algorithm is developed to obtain the numerical results. Numerical examples and sensitivity analyses are given to illustrate the model.
RAIRO - Operations Research
Cost reduction for setup and improvement of processes quality are the main target of this researc... more Cost reduction for setup and improvement of processes quality are the main target of this research along with free minimal repair warranty for an imperfect production System. This paper deals with the effect of setup cost reduction and process quality improvement on the optimal production cycle time for an imperfect production process with free product minimal repair warranty. Here the production system is subject to a random breakdown from an controlled system to an out-of-control state. Shortages are fully backlogged. The main target to minimize the total cost by simultaneously optimizing the production run time, setup cost, and process quality. A solution algorithm with some numerical experiments are provided such as the proposed model can illustrate briefly. Sensitivity analysis section is decorated for the optimal solution of the model with respect to major cost parameters of the system are carried out, and the implications of the analysis are discussed.
Mathematics
The present study focuses on a single-vendor, single-buyer supply chain model for a single type o... more The present study focuses on a single-vendor, single-buyer supply chain model for a single type of product with upgraded service provided to the buyer by the vendor. Vendors often increase their profit by providing a lower quality of a particular product. In this study, an advanced supply chain model is developed to increase service in the presence of an unreliable vendor and an online-to-offline (O2O) channeling system. The vendor provides lower quality items to the customer, even though they had committed to providing a certain quality product, in order to increase their profit. For more realistic results, demand is considered to be price-, quality-, and service-dependent. To advertise and sell the products, the manufacturer uses an online system, which the buyer also uses to choose and order the product, where the particular product is delivered to the customer by a third (offline) party; that is, the concept of an O2O retail channel is adopted to improve the service level of the...
For quality improvement purposes often times, a manufacturing unit has to change certain parts of... more For quality improvement purposes often times, a manufacturing unit has to change certain parts of equipment. Any such changes in the assembly line manufacturing system or production process involves a cost known as the setup cost. Minimizing the setup cost and improving the product quality is of prime importance in today's competitive business arena. This paper develops the effects of setup cost reduction and quality improvement in a two-echelon supply chain model with deterioration. The objective is to minimize the total cost of the entire supply chain model (SCM) by simultaneously optimizing setup cost, process quality, number of deliveries, and lot size. Numerical examples are provided to illustrate the model. 2010 Mathematics Subject Classification. Primary: 58F15, 58F17; Secondary: 53C35.