Corrigendum and a complement “A simple heuristic for vehicle routing – A variant of Clarke and Wrights saving method” [Int: J: Prod: Econ: 157 (2014) 74–79]
اصلاحیه و مکملی برای "یک اکتشاف ساده برای مسیریابی وسیله نقلیه - یک گونه دیگری از روش ذخیره سازی کلارک و رایت" [Int: J: Prod: Econ: 157 (2014) 74–79]-2018
A simple heuristic for vehicle routing - A variant of Clarke and Wrights saving method (International journal of Production Economics, 157 (2014), 74–79) contains a mistake that must be corrected. But the mistake also allows for a possible improvement of the search procedure which is demonstrated. We emphasise that the chosen sequence of the distribution, clockwise or anti-clockwise, can highly influence the vehicles fuel consumptions.
keywords: Vehicle routing |Transport |Scheduling |Heuristics |Inventories
Polynomial algorithm of inventory model with complete backordering and correlated demand caused by cross-selling
الگوریتم چند جمله ای مدل انبارداری با سفارش تاخیر شده کامل و تقاضای همبسته ایجاد شده توسط فروش تقاطعی-2018
In a paper published in the International Journal of Production Economics (IJPE) [Zhang, R., Kaku, I., Xiao, Y., 2012. Model and heuristic algorithm of the joint replenishment problem with complete backordering and correlated demand. International Journal of Production Economics 139 (1), 33–41], the authors proposed a joint replenishment problem (JRP) model with complete backordering and correlated demand caused by cross-selling. The model was transformed into minimizing a function with respect to multiples of a major items order cycle, and a heuristic algorithm was developed for near-optimal solutions. In this paper, we reinvestigate the problem and analyze the mathematical property of the model to develop an exact algorithm. The algorithm can obtain global optima and exhibits polynomial complexity.
keywords: Inventory |Joint replenishment problem |Polynomial algorithm |Complete backordering |Cross-selling
Optimal production-sales policies and entry time for successive generations of new products
سیاست های بهینه تولید - فروش و زمان ورود برای نسل های بعدی محصولات جدید-2018
This paper explores the optimal initial inventory at launch, sales plan, and introduction time for a new generation of a product. We propose a multi-generation demand model that accounts for supply constraints. A mathematical model of the supply-restricted multi-generation diffusion problem is then developed and the optimal sales policy is derived. Closed-form analytical expressions as well as numerical experiments are used to investigate the effect of consumers backlogging, cost of production capacity, unit profit margin for the products, market expansion by the new generation, and cannibalization of older generations. Through consideration of supply restrictions and lost sales, we are able to generalize previous findings on market entry policy by showing that there is a continuous range of optimal introduction times. We show that the inter-dependence between production capacity and initial inventory varies based on the introduction time of the new generation. We also provide an application of the proposed model in the case of Sonys PlayStation®3 game console. The results suggest that the company introduced the product too late and overproduced inventory which, as supported by empirical evidence, had a negative impact on the products performance. Limitations and considerations for the application of the model are also discussed.
keywords: Production and inventory management |Myopic and build-up policies |Market entry timing |Multi-generation innovation diffusion |PlayStation®3 game console
Coordinating manufacturers innovation and retailers promotion and replenishment using a compensation-based wholesale price contract
هماهنگ سازی نوآوری سازنده و تبلیغ و تجدید تدارکات خرده فروش با استفاده از یک قرارداد قیمت عمده فروشی مبتنی بر غرامت-2018
In this paper, coordination of a manufacturer-retailer chain is investigated where the manufacturer innovates in manufacturing process and the retailer applies promotional efforts. The market demand is assumed to be stochastic dependent on the retailers promotional and the manufacturers innovation efforts. The retailer uses a periodic review inventory system for replenishing items and decides on order-up-to level, review period and promotional efforts level. On the other hand, it is possible for the manufacturer to boost the market demand by innovation in manufacturing process. The retailers promotional and manufacturers innovation efforts not only affect their profits, but also impress their mutual profits and the supply chain performance in an indirect manner. Firstly, we develop the decentralized and centralized decision-making models along with solution procedures and concavity analysis to solve the models. Although the centralized model improves the profitability of the whole supply chain, it may reduce the profitability of either the retailer or the manufacturer. Therefore, we propose a new compensation-based wholesale price contract for encouraging actors to take part in the joint decision-making scheme. Moreover, a profit sharing strategy based on the bargaining power of members is proposed for distributing the surplus profit between members. Finally, the results of the decentralized, centralized and coordination models are compared using test problems and some sensitivity analyses are presented.
keywords: Supply chain coordination |Promotional and innovation |Periodic review |Inventory system |Compensation |Wholesale price contract |Profit sharing
A supply chain coordination mechanism for common items subject to failure in the electronics, defense, and medical industries
یک مکانیزم هماهنگی زنجیره تامین برای کالاهای رایج درمعرض خرابی در صنایع برق، دفاعی و پزشکی-2018
Prior research on inventory management for imperfect items assumes that such items can be dealt with through salvage or rework. Increased repair costs and decreased production costs arising from modern production processes (e.g. miniaturization, 3D printing), however, have led suppliers to increasingly eschew such solutions in favor of items and components which are discarded upon failure rather than being reworked or scrapped. In this paper, we first determine optimal supplier and buyer inventory policies for items which fail and which cannot be reworked. We then develop a supply chain coordination mechanism which uses a common replenishment time to coordinate a supply chain consisting of a single supplier and n buyers. Our coordination mechanism yields a global minimum for system-wide costs. Numerical examples are provided to illustrate important conditions under which our model is particularly effective at reducing system-wide costs.
keywords: Inventory |Supply chain coordination |Supply chain management
Optimal (z, Z)-type contracts for vendor-managed inventory
قراردادهای بهینه نوع (z, Z) برای موجودی فروش مدیریت شده-2018
We examine (z, Z)-type contracts for vendor-managed inventory (VMI) between a supplier and a retailer from the retailers perspective. A (z, Z) VMI contract specifies minimum and maximum inventory levels and their corresponding under- and over-stocking penalties. The retailer chooses the contract parameter values and the supplier decides whether to accept the contract and, if accepts, manages the inventory at the retailer and makes replenishment decisions. The supplier accepts the contract if his cost under VMI is no larger than his reservation cost. We provide the optimal (z, Z) VMI contract for the retailer and the corresponding optimal replenishment decisions for the supplier and show that the optimal (z, Z) VMI contract can coordinate the supply chain under mild conditions. We also examine a VMI contract with stockout penalty and holding-cost sharing, which is a special type of (z, Z) contract, and find that it may perform well compared with the optimal (z, Z) VMI contract, although its performance may depend on several factors such as the suppliers reservation cost.
keywords: Vendor-managed inventory |(z, Z)-type VMI contract |Stockout penalty |Holding-cost sharing
الگوریتم چند جمله ای مدل انبارداری با تاخیر کامل در سفارش و تقاضای همبسته ایجاد شده توسط فروش تقاطعی
سال انتشار: 2018 - تعداد صفحات فایل pdf انگلیسی: 6 - تعداد صفحات فایل doc فارسی: 23
در یک مقاله چاپ شده در مجله بین المللی اقتصادهای تولید (مدل و الگوریتم اکتشاف مسئله تجدید تدارکات مشترک با ترتیب بندی کامل و تقاضای همبسته، ژنگ و همکاران، صحفات33 تا 41)، نویسنده ها یک مدل مسئله تجدید تدارکات مشترک با ترتیب بندی کامل و تقاضای همبسته ایجاد شده توسط فروش تقاطعی را پیشنهاد کرده اند. این مدل به کمینه کردن یک تابع باتوجه به چندگانگی های یک چرخه سفارش یک کالای مهم تبدیل شد و یک الگوریتم اکتشاف برای راه حل های تقریبا" بهینه تولید شد. در این مقاله، ما مسئله را بررسی مجدد می کنیم و ویژگی ریاضی این مدل را جهت تولید یک الگوریتم واقعی تحلیل می کنیم. این الگوریتم می تواند به بهینگی عمومی دست یابد و پیچیدگی چند جمله ای را نشان می دهد.
کلیدواژه ها: انبارداری | مسئله تجدید تداکرات مشترک | الگوریتم چند جمله ای | تاخیر کامل در سفارش | فروش تقاطعی
|مقاله ترجمه شده|
Avoiding the capacity cost trap: Three means of smoothing under cyclical production planning
اجتناب از محبوس شدن هزینه ظرفیتی: سه راه برای هموارسازی تحت برنامه ریزی تولید چرخه ای-2018
Companies tend to set their master production schedule weekly, even when producing and shipping on a daily basis—the term for this is staggered deliveries. This practice is common even when there is no marginal cost of setting a new schedule. We argue that the practice is sound for companies that use the ubiquitous order-up-to (OUT) policy to control production of products with a significant capacity cost. Under these conditions, the length of the order cycle (time between schedule updates) has a damping effect on production, while a unit (daily) order cycle can cause significant capacity costs. We call this the capacity cost trap. Developing an analytical model based on industrial evidence, we derive capacity and inventory costs under the staggered OUT policy, showing that for this policy there is an optimal order cycle possibly greater than unity. To improve on this solution, we consider three approaches to smoothing: either levelling within the cycle, deferring excess production or idling to future cycles via a proportional OUT policy, or increasing the length of the cycle. By deriving exact cost expressions we compare these approaches, finding that smoothing by employing the proportional OUT policy is sufficient to avoid the capacity cost trap.
keywords: Inventory |Order-up-to policy |Reorder period |Overtime cost
The unlimited newsvendor: A general solution to a class of two-period newsvendor problems
روزنامه فروشی نامحدود: یک راه حل عمومی برای یک سری مشکلات روزنامه فروشی دو دوره ای-2018
We study a scheduling system in which a manufacturer, who sells to a retailer, determines the stocking level for a single product. The manufacturer has two opportunities to make a stocking decision. At the beginning of the first period, the manufacturer sets a preliminary stocking level based upon a set of initial demand estimates, possibly obtained from several sources, which consists of demand distributions and the probabilities that final demand will be drawn from any of these distributions. The uncertainty about which demand distribution will be realized is resolved after the first period, leaving the manufacturer with a known demand distribution but unknown final demand. At this point, the manufacturer can change the preliminary stocking level by either expediting additional supply or cancelling some—or all—of the initial stocking order. Expediting and cancelling carry a penalty cost. We develop a process for identifying the optimal initial and revised order quantities that can be applied regardless of the number of initial demand distributions. We also present a heuristic approach that can significantly simplify the process and, in many cases, maintain the quality of the solution.
keywords: Supply chain management |Two-period newsvendor |Stochastic inventory models |Expediting and cancellation
Joint pricing and inventory model for deteriorating items with expiration dates and partial backlogging under two-level partial trade credits in supply chain
قیمت گذاری مشترک و مدل انبارداری برای بخشهای تباهی با تاریخ های انقضا و جمع کردن جزئی تحت اعتبارات جزئی دو سطحی در زنجیره تامین-2018
This paper develops an inventory model for deteriorating items under a two-level partial trade credit with allowable shortages. This paper considers a supplier-retailer-customer supply chain in which (a) for settling the cost of purchasing, the retailer receives a partial trade credit from the supplier and at the same time the retailer offers a separate partial trade credit to the customer, (b) the downstream credit period not only increases demand but also opportunity cost, (c) the deterioration rate is non-decreasing over time and the product is fully deteriorated close to its expiration date, and (d) shortages are allowed. The objective of the problem is to determine the optimal selling price, the optimal replenishment cycle time and the time taken for the inventory to reach zero at the same time such that, the total profit per unit is maximized. Theoretical results are established. A numerical example is provided to illustrate the theoretical results and yield some managerial insights.
keywords: Inventory |Deterioration |Expiration dates |Trade credit |Shortages |Partial backlogging |Pricing