Showing papers by "S.R. Singh published in 2014"
TL;DR: A conceptual framework is developed that captures the frequency with which consumers check expiration dates and their willingness to pay for a perishable over its shelf-life and an optimal replenishment cycle, shortage period and preservation technology cost such that the net profit for the supply chain is maximised.
Abstract: The objective of this study is to develop a model for a two echelon supply chain, in which retailers’ demand is seasonal with expiration date and he invests on the preservation technology to reduce the rate of product deterioration. This paper examines consumers’ response to expiration dates for grocery store perishable products. We develop a conceptual framework that captures the frequency with which consumers check expiration dates and their willingness to pay for a perishable over its shelf-life.A solution procedure is presented to determine an optimal replenishment cycle, shortage period and preservation technology cost such that the net profit for the supply chain is maximised. A numerical example and sensitivity analysis are given to illustrate the model.
40 citations
TL;DR: In this paper, a multi-item inventory model is presented to optimize the unit time profit of inventory management for the products having an expiration date after which the product can not be sold.
Abstract: Inventory decisions in supply chain are crucial for its success. These decisions become more important for the products with expiration date. Making these decisions in inventory systems with multiple products is a challenging task for managers. Most approaches in the literature for optimizing decisions in such an environment consider only a single item inventory. This paper presents a multi item inventory model to optimize the unit time profit of inventory management for the products having an expiration date after which the product can not be sold. As on one side the shortage costs are significant, on the other side, to maintain appropriate inventory levels for such type of products and avoid shortages is a very problematic job. For validation, the model is simulated and the results are compared. This article offers an approach for optimization and thus has business significance.
26 citations
TL;DR: In this paper, the authors investigated the economic order quantity inventory model for a retailer under two-level of trade credit to reflect the supply chain management (SCM), where the selling items are perishable such as fruits, fresh fishes, gasoline, photographic films, etc.
Abstract: The present paper investigated the economic order quantity inventory model for a retailer under two-levels of trade credit to reflect the supply chain management (SCM). Here, it is assumed that the selling items are perishable such as fruits, fresh fishes, gasoline, photographic films, etc. It is assumed that potential worth of items can be increased by using preservation technology and the retailer’s trade credit period (M) offered by the supplier is longer than the customer’s trade credit period (N) offered by the retailer. It also assumed that the demand of the customer depends on the selling price of items. Theorems are developed to determine retailer’s optimal ordering policies and numerical examples are given to illustrate these theorems. It also observed that Goyal (1985), Shah (1993), Chung (1998) and Huang (2003) are the particular case of our proposed model. In addition, some managerial insights from the numerical examples are also concluded.
26 citations
TL;DR: In this article, a mathematical model with stock dependent demand and deterioration is developed to investigate the retailer's optimal inventory policy under the scheme of permissible delay in payment, where defective items are produced during the production process and delay period is progressive.
Abstract: Article history: Received June 1 2013 Received in revised format August 15 2013 Accepted August 15 2013 Available online August 17 2013 Trade credit is the most succeeding economic phenomenon which is used by the supplier for encouraging the retailers to buy more quantity. In this article, a mathematical model with stock dependent demand and deterioration is developed to investigate the retailer’s optimal inventory policy under the scheme of permissible delay in payment. It is assumed that defective items are produced during the production process and delay period is progressive. The objective is to minimize the total average cost of the system. To exemplify hypothesis of the proposed model numerical examples and sensitivity analysis are provided. Finally, the convexities of the cost functions and the effects of changing parameters are represented through the graphs. © 2013 Growing Science Ltd. All rights reserved
17 citations
TL;DR: In this paper, an inventory model for deteriorating items with stock-dependent demand and variable holding cost is presented, and the optimal policies are derived and the necessary and sufficient conditions of the existence and uniqueness of the optimal solution are theoretically carried out.
Abstract: Percentage of capital invested for holding the inventory of decaying item is more than that of non-decaying item. Unfortunately, most of the works done in the era of inventory controlling were and are putting forward without taking into account the aspect of variable holding cost of the deteriorating item. To bring concentrations of inventory practitioners, we present an inventory model for deteriorating item with stock-dependent demand and variable holding cost. Furthermore, non-instantaneous deteriorating approach is considered in this work. In the model, shortages are allowed and partially backlogged. The optimal policies are derived and the necessary and sufficient conditions of the existence and uniqueness of the optimal solution are theoretically carried out. As the special cases, the results of the proposed model with instantaneous and non-instantaneous deterioration rate and with and without shortages are shown. Finally, numerical examples are presented to demonstrate the developed model and the solution procedure. Sensitivity analysis of the optimal solution with respect to major parameters for giving managerial insights in conclusion is carried out.
15 citations
TL;DR: In this article, the authors present a review of the state of the art in the field of bioinformatics and applied it to the area of bio-medical data visualization.
Abstract: Article history: Received July 2 2013 Received in revised format September 7 2013 Accepted October 23 2013 Available online October 3
13 citations
TL;DR: In this paper, the authors derived a production inventory model over infinite planning horizon with flexible but unreliable manufacturing process and the stochastic repair time and derived the optimal policy for production system, which maximizes the total profit subject to some constraints under consideration.
Abstract: Article history: Received January 26 2014 Received in Revised Format July 5 2014 Accepted July 5 2014 Available online July 12 2014 This paper derives a production inventory model over infinite planning horizon with flexible but unreliable manufacturing process and the stochastic repair time. Demand is stock dependent and during the period of sale it depends on reduction on selling price. Production rate is a function of demand and reliability of the production equipment is assumed to be exponentially decreasing function of time. Repair time is estimated using uniform probability density function. The objective of the study is to determine the optimal policy for production system, which maximizes the total profit subject to some constraints under consideration. The results are discussed with a numerical example to illustrate the theory. © 2014 Growing Science Ltd. All rights reserved
12 citations
TL;DR: In this article, an EOQ model with two level of storage is developed when units in inventory deteriorate at a constant rate and demand is stock dependent, the salvage value is allied to deteriorated units.
Abstract: In this study, an EOQ model with two level of storage is developed when units in inventory deteriorate at a constant rate and demand is stock dependent. The salvage value is allied to deteriorated units. When stock level exceeds the capability of own warehouse (OW), it is to be kept in additional rented warehouse (RW) with higher holding cost than OW. The inventory held in RW is transferred to OW in continuous release pattern till the stock in RW gets exhausted. In developing the model it is assumed that shortages are allowed and partially backlogged. An algorithm is given to find the optimal solution. The sensitivity analysis is voted for out to analyse the effect of critical parameters on optimal solution by using MATHEMATICA–5.2 for the feasibility and applicability of our model.
11 citations
TL;DR: In this paper, the optimal cycle time is derived and the result is applied to numerical problems with the concept of space restriction in which demand is exponential, and deterioration is time dependent.
Abstract: With today's high competitive market, to afford the cost of warehouses is a very difficult task for the management in most of the countries. Managers are faced with the need to deliver a high level of service with minimal warehouse and inventory cost. Since a large ordered quantity increases the workforce of a warehouse. So it is necessary to develop tools which can help managers to handle warehouse to avoid the extra cost of handling.So it is economical to order the inventory according to available storage space. This problem is developed with the concept of space restriction in which demand is exponential, and deterioration is time dependent. Production is taken as a function of demand. The optimal cycle time is derived and the result is applied to numerical problems.
10 citations
TL;DR: In this article, the authors present a growing science journal, Growing Science Ltd., which is published by the University of South Carolina, USA. All rights reserved and available only online.
Abstract: © 2013 Growing Science Ltd. All rights reserved
7 citations
TL;DR: In this paper, the authors developed the coordination among different parties in a three-echelon supply chain with a centralized decision process, where multiple suppliers deliver various types of raw materials to a producer; producer produces different types of items, multi-items, in different units of the factory and supplies the items to multiple retailers.
Abstract: Article history: Received October 2 2013 Received in Revised Format Mach 17 2014 Accepted March 28 2014 Available online April 1 2014 The objective of this work is to generalize the three echelon supply chain model proposed by Jaber and Goyal (2008) [Jaber, M. Y., & Goyal, S. K. (2008). Coordinating a three-level supply chain with multiple suppliers, a vendor and multiple buyers. International Journal Production Economics, 116, 95-103.] for multi-items where single item was considered in production and distribution. This paper develops the coordination amongst different parties in a three-echelon supply chain with a centralized decision process. Producer, suppliers and retailers are the parties of the supply chain where multiple suppliers deliver various types of raw materials to a producer; producer produces different types of items, multi-items, in different units of the factory and supplies the items to multiple retailers. Different deterioration rates for finished items and raw materials are also considered. The model developed of this paper guarantees that the local costs for the members either remain the same as before coordination, or decrease as a result of coordination. A numerical example along with graphical illustrations is considered and the sensitivity analysis is provided to test the feasibility of the proposed model. © 2014 Growing Science Ltd. All rights reserved
TL;DR: In this paper, the authors have studied reliable production process with stock dependent unit production and holding cost under the effect of trade credit and the main objective of this paper is to optimize the total relevant cost for reliable manufacturing process.
Abstract: In today’s global market every body want to buy products of high level quality and to achieve a high level product quality supplier have to invest in improving reliability of production process. In present article we have studies reliable production process with stock dependent unit production and holding cost. Demand is exponential function of time and infinite production process wit non- instantaneous deterioration rate are considered in this paper. Whole study has been done under the effect of trade credit. The main objective of this paper is to optimize the total relevant cost for reliable production process. Numerical example and sensitivity analysis is given at the end of this paper. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */
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TL;DR: A multi-objective fuzzy chance constrained capacitated transportation problem based on fuzzy goal programming problem with capacity restrictions on commodities which are shipped from different sources to different destinations with graded mean integration method is presented.
Abstract: paper presents a multi-objective fuzzy chance constrained capacitated transportation problem based on fuzzy goal programming problem with capacity restrictions on commodities which are shipped from different sources to different destinations. The capacity of each origin and the demand of each destination are considered random in nature with fuzzy normal stochastic parameters following normal distribution with fuzzy mean and fuzzy variance respectively. These inequality constraints are also considered as fuzzy probabilistic in nature assuming to be triangular fuzzy numbers. Further, the supply and demand constraints are converted into equivalent deterministic forms. Then, we define the fuzzy goal tolerance limit of each of the objective functions which are then characterized by the associated membership functions. In the solution process, the fuzzy parameters are defuzzied by applying graded mean integration method which provided a satisfactory result. Further, an illustrative example is solved to demonstrate the effectiveness of the proposed model. Keywordsgoal programming, fuzzy chance constrained programming, capacitated transportation problem, multi objective decision making, graded mean integration method.
01 Jan 2014
TL;DR: A model for the design of a closed loop supply chain with green components, a joint economic production quantity model for a single vendor, single buyer system considering lot-splitting is proposed.
Abstract: In the past recent years, a growing environmental consciousness has been shaping the way society looks on green. Society’s attitude towards environmental issues has been changing and hence recoverable product environments are becoming an increasingly important segment of the overall push in industry. We have proposed a model for the design of a closed loop supply chain with green components. We have investigated a joint economic production quantity model for a single vendor, single buyer system considering lot-splitting. The effect of deterioration is taken into consideration. Here we have assumed that the vendor fulfils the buyer’s demand with the produced and remanufactured units, where the remanufactured items are considered as good as those of new items. Mathematical and numerical analysis are presented to describe the situation.
TL;DR: Wang et al. as discussed by the authors developed a three echelon supply chain model for items to determine the optimal reliability and production rate, which achieves the biggest total integrated profit for an imperfect manufacturing process.
Abstract: Article history: Received October 26 2013 Received in Revised Format July 5 2014 Accepted July 5 2014 Available online July 7 2014 In this study, we develop a three echelon supply chain model for items to determine the optimal reliability and production rate, which achieves the biggest total integrated profit for an imperfect manufacturing process. Here, we have taken a supplier, a manufacturer and a retailer in which supplier supplies raw materials to manufacturer, manufacturer produces perfect and imperfect quality items because practically it happens and manufacturer supplies perfect quality items to the retailers. In production system, production facility may shift from an in-control state to an out-ofcontrol state at any random time. The basic assumption of classical economic manufacturing quantity model is that all manufacturing items are of perfect quality but the assumption is not true in practice. The proposed study is formulated assuming that a certain percent of total product is defective. This percentage also varies with production rate and production run time. The defective items are restored in original quality by reworked at some costs to maintain the quality of products in a competitive market. Finally, numerical example and its graphical representation are given to illustrate the proposed model. Sensitivity analysis is also provided to test feasibility of the model. © 2014 Growing Science Ltd. All rights reserved
15 Sep 2014
TL;DR: An inventory model for deteriorating items with non- instantaneous deterioration rate and stock dependent demand is developed and optimal value of total cost is found.
Abstract: In this article we have studied the two- warehouse inventory problem with limited storage capacity of owned warehouse (OW).If Inventory level exceeds the storage capacity of owned warehouse (OW) then organization hires a rented warehouse (RW) at high holding cost than holding cost of owned warehouse (OW). We have developed an inventory model for deteriorating items with non- instantaneous deterioration rate and stock dependent demand. Partially backlogged shortages are allowed with time dependent backlogging rate and the whole study is done under the effect of inflation. Main objective of this paper is to find optimal value of total cost. Numerical illustrations and sensitivity analysis are given at the end of this article.
09 May 2014
TL;DR: Object of this study is to optimize the Total relevant cost, Payment time, ordered quantity, Preservation cost and sensitivity analysis is performed by changing values of some important parameters using Mathematical software Mathematica7.
Abstract: Deterioration rate is assumed to be an uncontrolled variable whereas through investment in preservation techniques it can be controlled up to certain level. In this paper we have studied effect of preservation technique for deteriorating items. So we have considered controllable deterioration rate with time dependent demand and trade credit in an inflationary environment. Objective of this study is to optimize the Total relevant cost, Payment time, ordered quantity, Preservation cost. At the end of this paper numerical illustration of this model and sensitivity analysis is performed by changing values of some important parameters using Mathematical software Mathematica7.
01 Nov 2014
TL;DR: In this article, the optimal retailer's replenishment policy for imperfect quality items in fuzzy environment is derived, where the effect of permissible delay in payments is also considered, and the ordering cost, purchasing cost, holding cost and selling price are taken as fuzzy numbers.
Abstract: The objective of this study is to derive the optimal retailer's replenishment policy for imperfect quality items in fuzzy environment. The effect of permissible delay in payments is also considered. It is assumed that production rate depends on the demand rate. Due to different preservation facilities, we consider that the deterioration rate is time dependent in own warehouse (O.W) and Wei-bull distribution in rented warehouse (R.W). The ordering cost, purchasing cost, holding cost and selling price are taken as fuzzy numbers.
01 Jan 2014
TL;DR: The model focuses on commodities having quadratic demand with trade credit policies and considers perishable stock whose deterioration starts immediately as soon as you store the items.
Abstract: The traditional inventory model assumes that a retailer accepts the offer of delay in payments since he does not have the capital with him. Even when he has to make the payments at the end of credit limit, he takes a loan to pay off the supplier. The model focuses on commodities having quadratic demand with trade credit policies. The commodities considered in this model are perishable stock whose deterioration starts immediately as soon as you store the items. We have considered all the factors which one retailer must kept in mind deciding his inventory level, the concept of inflation and time value of money is also considered.
01 Jan 2014
TL;DR: This work presents a deteriorating inventory model in which the unit holding cost is continuously based on the deterioration of the inventory with the time the item is in stock.
Abstract: Holding costs are determined from the investment in physical stocks and storage facilities for items during a cycle. In most of the research papers, holding cost rate per unit time for perishable inventory is assumed as constant. However, this is not necessarily the case when items in stock are decaying. In this work, paying better attention on the holding cost, we present a deteriorating inventory model in which the unit holding cost is continuously based on the deterioration of the inventory with the time the item is in stock. The deterioration rate is assumed as a Weibull distribution function. Declining market demand is considered in this paper. Shortages are allowed and partial backlogged. The partial backlogging rate is a continuous exponentially decreasing function of waiting time in purchasing the item during stock out period. Conditions for uniquely existence of global minimum value of the average total cost per unit time are carried out. Numerical illustration and sensitivity analysis are presented.
Journal Article•
01 Jan 2014
TL;DR: An integrated system with variable production is developed in fuzzy environment using triangular fuzzy numbers and signed distance method for defuzzification and sensitivity analysis with respect to the system parameters is executed.
Abstract: In this research article, an integrated system with variable production is developed in fuzzy environment. The demand rate is regarded as an increasing function of time. In developing the proposed model, it is assumed that the manufacturer takes the raw materials in multiple batches from the supplier, process them to produce finished products and deliver to the buyer in multiple shipments. The effect of inflation and time value of money is also taken into consideration. All the cost parameters are considered as triangular fuzzy numbers and signed distance method is used for defuzzification. The model is illustrated with numerical example and sensitivity analysis with respect to the system parameters is also executed.
01 Jan 2014
TL;DR: An inventory model with time-dependent demand rate and deterioration, allowing shortages, and sensitivity of the optimal solution with respect to changes in the values of the system parameters is studied.
Abstract: We develop an inventory model with time-dependent demand rate and deterioration, allowing shortages. The production rate is assumed to be finite and proportional to the demand rate. The shortages are partially backlogged with time-dependent rate. Inflation is also taken in this model. Inflation plays a very significant role in inventory policy. We developed the model in both fuzzy and crisp sense. The model is solved logically to obtain the optimal solution of the problem. It is then illustrated with the help of numerical examples. Sensitivity of the optimal solution with respect to changes in the values of the system parameters is also studied.
01 Jan 2014
TL;DR: The value of product life cycle with EoL scenario where the reverse logistics operations deal with the collection, sorting, cleaning, dissembling, and remanufacturing of the buyback products is determined.
Abstract: Owing to its strategic implications, reverse logistics has received much attention in recent years. Growing green concerns and advancement of reverse logistics concepts make it all the more relevant who can be achieved through the End-of-Life (EoL) treatment. In the proposed model, we develop a production inventory model with the reverse flow of the material. Here we determined the value of product life cycle with EoL scenario where the reverse logistics operations deal with the collection, sorting, cleaning, dissembling, and remanufacturing of the buyback products. The purpose of this paper is to develop an effective and efficient management of product remanufacturing. As a result, in this article, we establish a mathematical formulation of the model to determine the optimal payment period and replenishment cycle. Illustrative examples, which explain the application of the theoretical results as well as their numerical verifications, are also given. Finally, the sensitivity analysis is reported.
TL;DR: A three-echelon supply chain model, comprising of a supplier, a producer and a retailer where demand rate is functionally related to the selling price, shows that the model is not only stable but also economically feasible.
Abstract: In this paper, a three-echelon supply chain model has been explored, comprising of a supplier, a producer and a retailer where demand rate is functionally related to the selling price. In this study, it is assumed that customers are impatient in nature so shortages occur at the end of retailer. Production process assumes to be imperfect and defective items reworked and available for sale as good ones. Number of defective items present in supplier end follows the learning curve. The model has been explored numerically as well, an optimal solution has been obtained and the sensitivity of that solution has also been checked with respect to various system parameters. The final outcome shows that the model is not only stable but also economically feasible.
01 Oct 2014
TL;DR: Object of present study is to find optimum value of total cost in two different cases when model ends with shortages and second one is when model starts with the shortages.
Abstract: The social and environmental changes make the preservation technologies very important for those organizations which deal with deteriorating items. To study the effect of preservation technologies we have established a inventory model with preservation technology investment for the deteriorating items. The rate of production is directly related to the demand which is depends on time. The partially backlogged shortages are permitted with exponential backlogging rate under the learning effect on set-up and production costs. Objective of present study is to find optimum value of total cost in two different cases. First one is when model ends with shortages and second one is when model starts with the shortages. At the end of this article a numerical example and sensitivity analysis is discussed. The calculation part is done with the help of mathematical software Mathematica7.
01 Oct 2014
TL;DR: A profit function in finite time horizon is found under customer returns for deteriorating items which is price and time dependent and also considered as the function of price as well as the demand.
Abstract: We proposed a production model under customer returns for deteriorating items. We adopt a demand function which is price and time dependent. Customer returns is also considered as the function of price as well as the demand. Shortage is partially backlogged. In this paper, we find a profit function in finite time horizon. Finally, a numerical example is solved to illustrate the model.
01 Jan 2014
TL;DR: A two-warehouse economic order quantity model for deteriorating items in which demand increases with respect to time is investigated, with two types of model, first one is crisp model and second is fuzzy model.
Abstract: In the present study, we investigate a two-warehouse economic order quantity model for deteriorating items in which demand increases with respect to time. Shortages are allowed and partially backlogged. This study has been done with two types of model, first one is crisp model and the second is fuzzy model. In crisp model the capacity of the own-warehouse, holding cost, unit cost, shortage cost and opportunity cost are taken as the form of real numbers and in fuzzy model, these are taken as a triangular fuzzy numbers. Graded Mean Representation method is used to defuzzify the total cost function in case of fuzzy model. To illustrate the model numerical examples are given and sensitivity analysis has been done.
01 Jan 2014
TL;DR: In contrast to the traditional deterministic two-warehouse inventory model with shortages at the end of each replenishment cycle, an alternative model in which each cycle begins with shortages and ends without shortages is proposed.
Abstract: This article develops a two warehouse deterministic inventory model for deteriorating items with trapezoidal type demand under conditionally permissible delay in payments. A rented warehouse is used when the ordering quantity exceeds the limited capacity of the owned warehouse, and it is assumed that deterioration rates of items in the two warehouses may be different. In contrast to the traditional deterministic two-warehouse inventory model with shortages at the end of each replenishment cycle, an alternative model in which each cycle begins with shortages and ends without shortages is proposed. Deterioration rate is taken to be time-dependent. Shortages are allowed and fully backlogged. Then a solution procedure is shown to find the optimal replenishment policy of the considered problem. At last, article provides numerical example to illustrate the developed model. Sensitivity analysis is also given with respect to major parameters.
09 May 2014
TL;DR: In this article, a global warehouse and inventory model is presented and solved, where two separate warehouses, one is an own warehouse (OW) of finite dimension and other a rented warehouse (RW), for an infinite planning horizon.
Abstract: The purpose of this article is to evaluate the value of integrating tactical warehouse and inventory decisions. Therefore, a global warehouse and inventory model is presented and solved. We have considered two separate warehouses, one is an own warehouse (OW) of finite dimension and other a rented warehouse (RW), for an infinite planning horizon. Model focuses on stock-level dependent demand rate and a time dependent holding cost. We considered holding cost is an increasing function of time. In addition, we allow for shortages and complete backlogging. A numerical example and sensitivity analysis on some parameters are implemented to illustrate the model.