Deterioration Of Items Research Articles

Uncertain interval programming model for multi-objective multi-item fixed charge solid transportation problem with budget constraint and safety measure

This paper presents uncertain interval programming models for multi-objective multi-item fixed charge solid transportation problem with budget constraint and safety measure (MOMIFCSTPBCSM). The human languages usually involve imperfect or unknown information and are in the lack of certainty, and often, it is impossible to exactly describe an existing state or a future outcome. In using the probability theory, we must have enough historical information to estimate the probability distributions and in the case of fuzzy theory, we must have a trustworthy membership function, which is not easy to do. Thus, we often estimate the degree of belief with some hesitation that each condition may occur. To deal with such a situation, the uncertain interval theory may be very useful. Based on these facts, the parameters of the formulated problem are chosen as uncertain intervals. We consider unit transportation costs, fixed charges, transportation times, deterioration of items, supplies at origins, demands at destinations, conveyance capacities, budget at each destination, selling prices and purchasing costs, and we assume the safety factor and the desired safety measure are interval uncertain parameters. To formulate the proposed MOMIFCSTPBCSM, we use interval theory and uncertain programming techniques to develop two different models: an Expected Value Model and a Chance-Constrained Model. The equivalent deterministic models are formulated and solved using a linear weighted method, a fuzzy programming method and the goal programming method.

Electronic Components Inventory Model for Deterioration Items with Distribution Centre using Genetic Algorithm

Electronic Components Inventory Model for Deterioration Items with Distribution Centre using Genetic Algorithm

A cost sharing-based coordination mechanism for multiple deteriorating items in a one manufacture-one retailer supply chain

In this paper, an inventory model for deterioration items in a two-echelon supply chain including one retailer and one manufacturer is proposed by considering the stock and price dependent demand and capacity constraint for holding inventories. First, the model is presented as a leader-follower game in which the manufacturer announces wholesale prices. Second, the retailer decides for the order quantity and price of the items based on the wholesale prices. Then, by introducing the integrated model of the supply chain, a cost-sharing contract is applied to coordinate the manufacturer and the retailer. On the other hand, by using the convergence properties of the model and proving non-concavity of the problem, a meta-heuristic algorithm, namely iterative local search (ILS) is proposed to solve the models. The results show the determinant role of the capacity constraint on the optimal decisions and the ability of the proposed contract to coordinate the supply chain. Moreover, it is shown that the proposed algorithm outperforms the well-known interior point algorithm as the results of the initiations embedded in it for the special problem.

Optimal Policies for Price Sensitive Quadratic Demand with Preservation Technology Investment Under Inflationary Environment

The proposed EOQ model is a genuine attempt to manage retailer’s inventory when retailer’s stock is comprised of defective as well as constantly deteriorating items. Defective items in inventory are managed by selling them at discounted rate after a quality check process. Deterioration of items is controlled by investing suitable amount in preservation technology. The study assumes price sensitive quadratic demand incorporating the effect of inflation leading to a realistic situation. The objective of this paper is to maximize the retailer’s total profit with respect to cycle time, selling price, and preservation technology investment. Numerical examples are given to validate the model, and sensitivity analysis of inventory parameters is done to understand their effect. The outcome of this paper is applicable to goods like utility vehicles, stationary items, Fashion accessories, Cloths, Footwears, etc.

Economic order quantity model for growing items with incremental quantity discounts

Certain inventory items are living organisms, for example livestock, and are therefore capable of growing during the replenishment cycle. These items often serve as various saleable food items downstream in supply chains. The purpose of this paper is to develop a lot sizing model for growing items if the supplier of the items offers incremental quantity discounts. A mathematical model is derived to determine the optimal inventory policy which minimises the total inventory cost in both the owned and rented facilities. A solution procedure for solving the model is developed and illustrated through a numerical example. Sensitivity analysis is performed to demonstrate the response of the order quantity and total costs to some key input parameters. Incremental quantity discounts result in reduced purchasing costs; however, ordering very large quantities has downsides as well. The biggest downsides include the increased holding costs, the risks of running out of storage capacity and item deterioration since the cycle time increases if larger quantities are purchased. Owing to the importance of growing items in the food supply chains, the model presented in this article can be used by procurement and inventory mangers when making purchasing decisions.

Low Carbon Supply Chain Coordination for Imperfect Quality Deteriorating Items

Nowadays, many countries have implemented carbon pricing policies. Hence, the industry adapts to this policy while striving for its main goal of maximizing financial benefits. Here, we study a single manufacturer–retailer inventory decision considering carbon emission cost and item deterioration for an imperfect production system. This study examines two models considering two cases of quality inspection. The first is when the buyer performs the quality inspection, and the second is when the quality inspection becomes the vendor’s responsibility so that no defective products are passed to the buyer. Carbon emission costs are incorporated under a carbon tax policy, and we consider the carbon footprint from transporting and warehousing the items. The objective is to jointly optimize the delivery quantity and number of deliveries per production cycle that minimize the total cost and reduce the total carbon emissions. This study provides solution procedures to solve the models, as well as two numerical examples.

Purchasing inventory models for exponential demand with deteriorating items and discounted cost-in third order equation

The purpose of this article is to present a solution procedure for the inventory problem of deteriorating items and exponential demand and taking account of time value of money. Also, most of the works on inventory models do not take the optimal solution in higher order equation. In this paper, inventory models for deteriorative items with time dependent exponential demand under inflation and the optimum solution is derived in higher order equations. Two models are developed and the optimum time and total cost are derived: 1) when the demand is exponential with deteriorative items; 2) demand is exponential with deteriorative items and discounted cost. Mathematical models are developed for each model and the optimum time and optimal lot size which minimises the total cost is derived. The objective of this paper is to find the optimal cycle time and optimal quantity which minimise the total cost. Numerical examples are given to illustrate the theoretical results and made the sensitivity analysis of parameters on the optimal solutions. The validation of result for this model was coded in Microsoft Visual Basic 6.0.

Purchasing inventory models for exponential demand with deteriorating items and discounted cost-in third order equation

The purpose of this article is to present a solution procedure for the inventory problem of deteriorating items and exponential demand and taking account of time value of money. Also, most of the works on inventory models do not take the optimal solution in higher order equation. In this paper, inventory models for deteriorative items with time dependent exponential demand under inflation and the optimum solution is derived in higher order equations. Two models are developed and the optimum time and total cost are derived: 1) when the demand is exponential with deteriorative items; 2) demand is exponential with deteriorative items and discounted cost. Mathematical models are developed for each model and the optimum time and optimal lot size which minimises the total cost is derived. The objective of this paper is to find the optimal cycle time and optimal quantity which minimise the total cost. Numerical examples are given to illustrate the theoretical results and made the sensitivity analysis of parameters on the optimal solutions. The validation of result for this model was coded in Microsoft Visual Basic 6.0.

Three-echelon supply chain model considering carbon emission and item deterioration

This study considers an integrated three-echelon supply chain with carbon emissions from transportation and warehousing, as well as disposing of the deteriorated items. It is assumed that transportation and emission reduction policies affect fuel consumption, which in turns affects costs and carbon emissions. The proposed model simultaneously optimizes the number of deliveries and the delivery size from a supplier to a third-party logistics service provider (3PL), and from the 3PL to the buyer in a three-echelon supply chain model considering deterioration and carbon emission. A numerical example and sensitivity analysis are presented to illustrate the proposed model. The result shows the benefit of supply chain integration in terms of total supply chain cost and carbon emission reduction.

A new production and shipment policy for a coordinated single-vendor single-buyer system with deteriorating items

This paper proposes a new production and shipment policy for a coordinated single-vendor single-buyer system with the consideration of item deterioration to minimize the joint total cost. To be more close to reality, the inventory level of the vendor is assumed to be an inflexion form which is different from the extant researches. Also, we incorporate the transportation time and the deterioration during delivery process into the coordinated model which are always neglected in the literature. A mathematical model is developed to determine the number of shipments per production cycle, the time interval between two successive shipments and the initial inventory when the production cycle starts. Different from the previously published work which concentrates on the equal sized shipment policy, we explore properties that the optimal shipment policy exhibit. We simplify the mathematical model developed based on the explored properties and propose a solution procedure to obtain near optimal solution. Numerical experiment on classical and randomly generated instances indicates that the joint total cost per unit time can be continuously reduced, comparing with the commonly applied equal sized shipment policy.

Optimal Replenishment for Perishable Products with Inventory-Dependent Demand and Backlogging under Continuous and Discrete Progressive Payments

Managing material and cash flows attracts concerns of physical and financial departments in most companies. We, therefore, focus on optimizing the replenishment policy for a channel with stock-dependent demand considering item deterioration and order backlogging under two financial schemes of progressive trade credit periods. We take both the continuous payment regime (CPR) and discrete payment regime (DPR) into account in the progressive trading process, which generates ten distinct scenarios. We show that the profit functions may not necessarily be concave and accordingly give a corresponding computing algorithm, which relaxes the convexity assumptions of objective functions in the existing literature and consequently enrich the research. We address the formulation characterization and the logic of pursuing global optimization from models arising in all settings. Computational studies and simulations are conducted to illustrate the effect of various parameters on the optimal replenishing policy and profit. Numerical experiments show that the CPR scheme is dominantly prior to DPR for long replenishment time intervals, whereas it is exactly the opposite for short time intervals. We also examine the impact of the shortage cost and deteriorating rate on optimum ordering policy and channel performance. Finally, future research directions are addressed in the end.

PCN162 - Evaluation Of The Disease-Specific Items On The Eortc In Hepatocellular Carcinoma Patients Treated With Lenvatinib Or Sorafenib

To determine whether individual items on the EORTC-QLQ-C30 and hepatocellular carcinoma subscale are associated with statistically significant differences over the course of treatment for patients with unresectable hepatocellular carcinoma (uHCC). This was a multicenter, randomized, open-label, non-inferiority Phase 3 study comparing lenvatinib (LEN) to sorafenib (SOR) as first-line uHCC systemic treatments. 954 patients were randomized to LEN (N=478) or SOR (N=476). Analyses on the individual items of the EORTC QLQ-C30 and HCC18, were conducted using longitudinal generalized estimation equations (GEE) of the post-baseline, treated period assessments for these items. Forest plots of the odds ratios (OR) and associated confidence intervals (CI) from the GEE analyses were generated to characterize the likelihood of a 2-grade categorical deterioration (eg, deteriorate by 2 categories on the verbal response scale) on individual items for patients treated with LEN compared to SOR during the treatment period. The likelihood of patients experiencing a 2-grade deterioration over the course of the post-baseline treatment period was statistically equivalent for most EORTC-QLQ-C30 and HCC18 items (OR ~ 1.0) with the exception of pain in the shoulder, weight being too low, and reduced activity. Patients treated with SOR were 38% less likely to observe a 2-grade deterioration in shoulder pain (OR=0.7107, CI=0.5611-0.9003, p-value=0.0046). Patients treatment with LEN were 25% less likely to observe a 2-grade deterioration in weight being too low (OR=1.2502, CI=1.0014-1.5609, p-value=0.0485) and 27% less likely to observe a 2-grade deterioration in activity reduction (OR=1.2658, CI=1.0158-1.5774, p-value=0.0358). These data provide detailed information on the cumulative probability of categorical deterioration of individual items on the EORTC-QLQ-C30 and HCC18. These results show a similar trend with additional benefit of LEN in terms of anorexia or activity over the course of treatment, which are two key areas for patients especially the ability to perform activities.

Joint dynamic pricing and preservation technology investment for an integrated supply chain with reference price effects

In this paper, we propose a system of joint dynamic pricing and preservation technology investment decisions for deterioration items in an integrated supply chain management environment involving a manufacturer and a retailer, a controllable deterioration rate, and price-dependent demand. Because the purchasing decisions of consumers usually involve psychologically encoded prices based upon past shopping experiences, the effects of initial reference prices are also incorporated into the proposed model. An optimal dynamic pricing and preservation technology investment model is then established to determine joint strategy, maximizing the discounted total profit over an infinite time horizon from the perspectives of the retailer and integrated supply chain. We also characterize the properties of the optimal pricing and preservation technology investment decisions, and conduct numerical studies to investigate the impact of initial reference price and various system parameters on the optimal strategies and discounted total profit for the retailer/integrated supply chain. Finally, we offer concluding remarks and suggestions for future studies.

Dynamic pricing, quality investment, and replenishment model for perishable items

AbstractThe deterioration of perishable items results not only in direct quantitative losses, but also in qualitative losses, which would reduce the customer acceptability. To maintain or improve the quality level, sellers usually invest in functionality, aesthetics, safety or any other attributes. In addition to quality, price also plays a critical role in influencing the purchase choice of consumers and the profit of a firm. Most inventory management models for perishables are restricted to physical quantity deterioration and do not address joint dynamic pricing and quality investment strategies. This paper studies an optimal replenishment model with dynamic pricing and quality investment for perishable products, where the quality and physical quantity deteriorate simultaneously. The demand rate is decreasing in sales price and increasing in quality level. A dynamic optimization model is proposed to maximize the total profit per unit time and solved on the basis of Pontryagin's maximum principle. The optimal joint dynamic pricing, quality investment, and replenishment policy is obtained. A numerical example and sensitivity analysis on the key system parameters are presented to illustrate the validity of the theoretical results. Some managerial implications for the pricing and quality investment for the perishables are provided.

EOQ models for deteriorative items with constant, linear and quadratic holding cost and shortages - a comparative study

In the classical inventory model the holding cost was assumed to be constant. However, in reality, holding cost may not always be constant. The holding cost may be time dependent. In this paper, a production inventory model with deteriorating items with constant, linear and quadratic holding cost is considered and also a comparative study is carried out between constant, linear and quadratic holding costs. Three models are developed. In three models, the optimum time and total cost are derived when the holding cost is: 1) constant; 2) linear; 3) quadratic. A mathematical model is developed for each model and the optimal production lot size which minimises the total cost is derived. The optimal solution is derived and an illustrative example is provided. The validation of result in this model was coded in Microsoft Visual Basic 6.0.

Optimal inventory replenishment and pricing for a single-manufacturer and multi-retailer system of deteriorating items

This paper studies an integrated optimisation model of inventory replenishment and pricing decisions in a single-manufacturer multi-retailer system of deteriorating items. Two meta-heuristic algorithms, i.e., improved particle swarm optimisation incorporated with SA mechanism (SAPSO), and a continuous domain ant colony optimisation algorithm (CDACO) are developed. Experiments show that two algorithms are effective for solving the model; however, SAPSO has higher effectiveness, efficiency and accuracy than CDACO. Sensitivity analysis shows that price elasticity coefficient significantly impacts decisions of production and retailing, giving managerial implication that reducing price fluctuation can increase profit. However, the effect of deterioration of items is not significant both for cost and profit.

EOQ models for deteriorative items with constant, linear and quadratic holding cost and shortages - a comparative study

EOQ models for deteriorative items with constant, linear and quadratic holding cost and shortages - a comparative study

Optimal control model for finite capacity continuous MRP with deteriorating items

A general model for continuous material requirements planning problem is proposed which contains of reworking of returned items along with deterioration of items. In the proposed model there are separated stocks for manufactured, returned and reworked items and also it is possible to consider returned items from both inventories of manufactured and reworked items. A general finite time linear quadratic optimal control problem is presented to attain the goal values for inventories, demands and productions. The goal values for inventories, demands and production can be considered as the capacity of stocks, scheduled demand and capacity of transportation respectively. Since the time is considered as a continuous parameter, the carrying cost of production process is more real than the periodic approach wherein time is considered as a discrete parameter. Finally a solution method is presented and numerical simulations are provided to validate the approach.

An economic production model for deteriorating items and time dependent demand with rework and multiple production setups

Recently, much emphasis has given to study the control and maintenance of production inventories of the deteriorating items. Rework is one of the main issues in reverse logistic and green supply chain, since it can reduce production cost and the environmental problem. Many researchers have focused on developing rework model, but few of them have developed model for deteriorating items. Due to this fact, we take up productivity and rework with deterioration as the major concern in this paper. In this paper, a production-inventory model with deteriorative items in which one cycle has n production setups and one rework setup (n, 1) policy is considered for deteriorating items with stock-dependent demand in case 1 and exponential demand in case 2. An effective iterative solution procedure is developed to achieve optimal time, so that the total cost of the system is minimized. Numerical and sensitivity analyses are discussed to examine the outcome of the proposed solution procedure presented in this research.

Production inventory models for deteiorative items with three levels of production and shortages

In this paper, three level production inventory models for deteriorative items are considered under the variation in production rate. Namely, it is possible that production started at one rate, after some time, switches to another rate. Such a situation is desirable in the sense that by starting at a low rate of production, a large quantum stock of manufacturing items at the initial stage are avoided, leading to reduction in the holding cost. The variation in production rate results in consumer satisfaction and potential profit. Two levels of production inventory models are developed, and the optimum lot size quantity and total cost are derived when the production inventory model without shortages is studied first and a production inventory model with shortages next. An optimal production lot size, which minimizes the total cost, is developed. The optimal solution is derived and a numerical example is provided. The validation of the results in this model was coded in Microsoft Visual Basic 6.0.