On the multi-product newsvendor with bounded demand distributions
روزنامه فروش چند محصولی با توزیع های محدود تقاضا-2018
We consider a multi-item newsvendor problem with side constraints and common continuous demand distributions that are bounded implying that the items’ profit functions are nondifferentiable. In particular we focus on the cases of uniform and triangular distributions. These distributions naturally describe demand that is guaranteed to exceed a certain threshold – for example, consumption of basic food products or electric power consumption over any given day. Moreover, in practice, it is often difficult to estimate the demand distribution. Accordingly, the uniform and triangular distributions become default modeling choices when only information regarding the bounds and possibly the mode of the distribution is known. We generalize a previous quadratic programming model for uniformly distributed demand on to allow a to be nonzero and to allow the order quantity to be smaller than a. We study the corrected model and propose an efficient algorithm for determining an optimal solution. The algorithm is motivated by a structural result of an upper bound on the number of guaranteed shortage products, which typically appear in multiproduct settings with a positive demand distribution lower bound. The performance of our specialized algorithm is compared to that achieved when solving our formulation with a piecewise quadratic objective using a state-of-the-art standard solver. We also extend the modeling technique to propose a nonlinear programming formulation for triangular demand distributions. A similar approach can be adopted to approximate other demand distributions with a possibly non-finite support, such as truncated normal with strictly positive lower bounds.
keywords: Logistics |Inventory management |Multi-item newsvendor |Quadratic programming |Convex programming
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
The impact of abusing return policies: A newsvendor model with opportunistic consumers
تاثیر سوء استفاده از سیاست های بازگشتی: یک مدل روزنامه فروشی با مشتری های فرصت طلب-2018
Consumers may return a product for a variety of reasons, such as the product having the wrong color or size, having poor functionality, being damaged during shipment, or simply prompting regret for an impulsive purchase. Retailers generally provide lenient return policies not only because they may signal high quality but also because they act as risk relievers for consumers’ purchasing decision processes. However, increasing product returns have become particularly challenging for the efficient management of inventory. As such, at the crux of a holistic inventory model lies the understanding of consumer return behavior. In this study, we introduce a variant of the classical single-period inventory (newsvendor) model with returns, in which heterogeneous consumers decide, based on their post-purchase valuation of the product, whether to return the product after using it. From the perspective of the retailer, such deliberate returns may abuse the return policy, which in turn may exacerbate reverse logistics and environmental costs. To that end, we incorporate demand uncertainty and consumer valuation uncertainty by explicitly gauging return probabilities and differentiated salvage values into a newsvendor model. We derive analytical results for the profit-maximizing order quantity for a single-period product that comes with a retailer return policy and exclusively identify the impact of return type as abused or normal. Also offered are closed-form optimal solutions in the cases where market demand is exponentially or uniformly distributed. Structural and numerical results lend managerial insight into how optimal ordering amount, profit, return rates and salvage values change with the price, return window, and hassle cost of returning the product.
keywords: Inventory management |Consumer behavior |Product returns |Fraudulent proclivity |Uncertain demand |Return policy
Operational safety: The hidden cost of supply-demand mismatch in fashion and textiles related manufacturers
ایمنی عملیاتی: هزینه مخفی عدم هماهنگی عرضخه - تقاضا در سازنده های مربوط به مد و منسوجات-2018
Inventory management is a focus for operations management scholars and operations managers. Previous literature mainly investigated the relations between firms inventory and financial performance. However, the relation between firms inventory and non-financial performance (e.g., social outcome) is less clear. This study takes a fresh perspective to examine the impacts of supply-demand mismatch on firms safety performance. Based on a sample set from fashion and textiles related manufacturers, the analysis suggests that supply-demand mismatch (measured by inventory volatility) associates with a higher likelihood of safety incidents. The impact is more salient where the firms are operating in complex (labour intensive) and tightly coupled (high production capacity utilization) environments. This study provides significant contributions to the inventory management literature, occupational health and safety management literature and operational managers.
keywords: Inventory management |Occupational health and safety |Empirical study |Fashion and textiles
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
Inventory component volatility and its relation to returns
فراریت مولفه انبارداری و رابطه آن با بازگشت ها-2018
Members of manufacturing supply chains have to take many risks. Prior academic work emphasizes that inventory management is one of the pivotal sources for operational risks, particularly in terms of inventory volatility and excess inventory. Recent research shows that total inventory volatility not only poses a threat to a firms operational performance, but also increases a firms abnormal stock returns. However, the volatility impact of the three underlying inventory components—raw materials, work-in-process, and finished goods—is still unresolved. We argue that the relationship between inventory volatility and stock returns differs between the three inventory components since they each relate to different stages of the supply chain. Using a sample of U.S. manufacturing firms over the period 2005 to 2013, we empirically examine the relationship between inventory component volatility and stock returns. We find a significant positive association between work-in-process inventory volatility and stock returns, a significant negative association between finished goods inventory volatility and stock returns, and no significant association between raw material inventory volatility and stock returns. In additional analyses, we find that types of industry dynamism influence these relationships. The results of this study provide a more detailed picture regarding the investor perception of inventory dynamics.
keywords: Operational risk |Inventory management |Stock returns |Raw material |Work-in-process |Finished goods
Bank credit and corporate working capital management
اعتبار بانکی و مدیریت سرمایه در گردش شرکت-2018
We investigate how changes in the availability of bank credit influence how public firms man age their working capital, which is essential to their operations. In doing so, we provide an en hanced understanding of what significantly influences corporate working capital management. We find that changes in the availability of bank credit significantly influence a number of as pects of a firms working capital policies, and these effects often differ across firms that are more or less dependent on bank financing. Interestingly, our evidence points to the importance of the changing mix of U.S. companies for working capital practices.
Keywords: Bank credit ، Working capital management ، Cash management ، Inventory management ،Trade credit ، Supply chain financing
ارزیابی قابلیت اطمینان استراتژیهای مدیریت سهام در تقاضای وابسته
سال انتشار: 2017 - تعداد صفحات فایل pdf انگلیسی: 4 - تعداد صفحات فایل doc فارسی: 12
در این مقاله، یک رویکرد روش شناختی پیشنهاد شده که این رویکرد، امکان محاسبه کمیت سهام ایمنی در تقاضای وابسته را با توجه به الزامات قابلیت اطمینان زنجیره تامین فراهم می کند. انواع مختلف استراتژیهای مدیریت دارایی در تقاضای وابسته بررسی شد؛ نتایج کل محاسبه هزینه ها با توجه به قابلیت اطمینان بدست آمد.
کلید واژه ها: قابلیت اطمینان زنجیره تامین | مدیریت دارایی | تقاضای وابسته | نظم کامل
|مقاله ترجمه شده|
Relationship between Inventory Management and Uncertain Demand for Fast Moving Consumer Goods Organisations
ارتباط بین مدیریت موجودی و تقاضای نااطمینانه برای حرکت سریع کالاهای مصرفی سازمان-2017
This paper addresses relationship between inventory management and uncertain demand. It also assesses the effects of uncertain demand on inventory management in the fast moving consumer goods (FMCG). Inventory management should be given attention it deserves in order for the business to stay competitive, flexible for the demand and at low cost. Inventories are difficult to manage and control, and inventory managers find it challenging to know when to order and how much to order. The research was descriptive in nature and was conducted through the use of quantitative research methods. A survey questionnaire was used to collect primary data from five FMCG organisations in the manufacturing industry around Johannesburg. A sample of 255 respondents was involved in this study. According to the findings, significant relationship between inventory management and uncertain demand exists. The findings imply that poor inventory management will result in demands not being satisfied, organisations will either have too much or too little on hand, and this will result to the organisations’ failure.
Keywords: Fast moving consumer goods (FMCG) | inventory management | uncertain demand | Economic Order Quantity (EOQ) | Activity Based Cost analysis (ABC)
A metacognitive perspective on decision making in supply chains_ Revisiting the behavioral causes of the bullwhip effect
چشم انداز فراشناختی در مورد تصمیم گیری در زنجیره های عرضه: بازخوانی علل رفتاری اثر شکارچی-2017
Because supply chains are complex systems of interdependent subsystems, decisions by one partner can cause large and unpredictable system-wide effects, including the so-called “bullwhip” effect. The predominant approach to mitigating the bullwhip effect has been to provide additional information to supply chain members. However, recent research suggests that even the most information rich conditions lead decision makers to create the bullwhip effect. We propose an adaptive, learning perspective on supply chain decision making. Our model recognizes the key role of meta-decisions whereby decision makers decide whether or not to incorporate additional information into their decision making process based on the extent to which they understand cause and effect relationships. An experiment in which participants made orders in a simulated supply chain confirms that decision makers that felt they understood cause and effect relationships were more likely to incorporate relevant information into their decision processes, and thereby made better ordering decisions.
Keywords: Supply chain coordination | Information use |Inventory management |Cognition and reasoning