سرمایه گذاری فن آوری جهت جلوگیری از وخامت موجودی

The objective of this study is to develop a deteriorating inventory policy when the retailer invests on the preservation technology to reduce the rate of product deterioration. A solution procedure is presented to determine an optimal replenishment cycle, shortage period, order quantity and preservation technology cost such that the total profit per unit time is maximized. A numerical example and sensitivity analysis are presented to illustrate the model.

Deteriorating inventory had been studied in the past decades (Dave and Patel, 1981; Kang and Kim, 1983; Wee, 1997; Lodree and Uzochukwu, 2008; Bhunia et al., 2009; Chang et al., 2010), and they usually focused on: (1) constant or variable deterioration rate, (2) quantity discount and (3) supply chain coordination. However, investing on preservation technology (PT) for reducing deterioration rate has received little attention in the past years. The consideration of PT is important due to rapid social changes and the fact that PT can reduce the deterioration rate significantly. Moreover, sales, inventory and order quantities are very sensitive to the rate of deterioration, especially for fast deteriorating products (see Fig. 1). The higher rate of deterioration would result in a higher total annual relevant cost and a lower demand rate (Yang and Wee, 2006; Johnny et al., 2007). Ouyang et al. (2006) found that if the retailer can reduce effectively the deteriorating rate of item by improving the storage facility, the total annual relevant inventory cost will be reduced. Wang et al., 2007 and Wang et al., 2007 focused on deciding on resources portfolio and allocating resources to various orders in each production period. Many enterprises invest on equipments to reduce the deterioration rate and extending the product expiration date. For example, refrigeration equipments are used to reduce the deterioration rate of fruits, flowers and sea foods in the supermarket. Murr and Morris (1975) showed that a lower temperature will increase the storage life and decrease decay. Moreover, drying or vacuum technology are introduced to reduce the deterioration rate of medicine and food stuff. Zauberman et al. (1990) developed a method for color retention of Litchi fruits with SO2 fumigation. The tradeoff between the increased cost of investment and the increased profit due to decreased deterioration rate is the focus of our study. Full-size image (18 K) Fig. 1. Inventory system for various reduced deterioration rate m (ξ). (k=0.02 is the original deterioration rate). Figure options Deteriorating inventory was originally studied by Ghare and Schrader (1963). Products are assumed to deteriorate with time resulting in a decreasing utility or price from the original one. Some of the examples are fresh seafood, battery, volatile chemicals and semiconductor chips. Nye et al. (2001) developed a model to predict optimal production batch sizes and investments in setup reduction. Lee (2004) developed a cost/benefit model to support investment strategies on inventory and preventive maintenance in an imperfect production system. Lin and Hou (2005) considered an inventory system with random yield in which both the setup cost and yield variability can be reduced through capital investment. Jie Li et al. (2008) constructed and analyzed a return-on-investment maximization model for inventory and capital investment in setup and quality operations under an investment budget constraint. Hsu et al. (2007) addressed a deteriorating inventory replenishment model with expiration date and uncertain lead time. Their model developed a strategy to reduce the supplier's lead time by investing in the supplier's managing cost. Affisco et al. (2002) showed that improving deterioration is not necessarily a linear function of investment cost. They investigated the potential impact of investments in quality improvement and setup cost reduction. Uçkun et al. (2008) derived the optimal investment levels that maximized profit by decreasing inventory inaccuracy. Lee (2008) developed cost/benefit models for investments in quality improvements to measure the impact of quality programs and to predict the return of investment in these programs in a multi-level assembly system. Chung and Wee (2008) considered the green-component life-cycle value on design and reverse manufacturing in semi-closed supply chain. Other researchers such as Padmanabhan and Vrat (1990); Moon (1994); Hong and Hayya (1995); Banerjee et al. (1996); Yang and Wee (2001); Kogan and Spiegel (2006); Liu and Çetinkaya (2007); Gurnani et al. (2007); Wang et al., 2007 and Wang et al., 2007; Honggeng Zhou et al. (2009); Mathur and Shah (2008); Jaber and El Saadany (in press) considered investment constraint issue. In this study, a solution procedure is developed to determine the retailer's replenishment and preservation technology investment policy for deteriorating items with a constant rate of deterioration and demand. The original deterioration rate is assumed to be k . A reduced deterioration rate of m (ξ ) is assumed when the retailer's investment cost on preservation equipments or technology is ξ . That means that the resultant deterioration rate of the product, ΓpΓp is k−m(ξ) when the PT cost is ξ. When shortages occur, some of the customers will wait for the next replenishment, while others will seek alternative supply.

The products with high deterioration rate are always crucible to the retailer's business. However, the tradeoff between the increased cost due to investment on improving deterioration rate and the increased profit due to decreased deterioration rate is complex. This study develops a deteriorating inventory model where the retailer may invest in the PT cost. A solution procedure is also derived to consider the capital constraint. Sensitivity analysis shows that when the available capital increases, the retailer's unit time profit increases, and if the deterioration rate increases, more investment is needed. The results give management managerial insights in the amount of investment on PT equipments or facilities.