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Stock Levels (stock + level)

Distribution by Scientific Domains
Engineering33%
Business, Economics, Finance and Accounting33%

Selected Abstracts

STOCK LEVELS AND DELIVERY RATES IN VENDORMANAGED INVENTORY PROGRAMS

PRODUCTION AND OPERATIONS MANAGEMENT, Issue 1 2001
BEN A. CHAOUCH
Using the latest information technology, powerful retailers like Wal-Mart have taken the lead in forging shorter replenishment-cycles, automated supply systems with suppliers. With the objective to reduce cost, these retailers are directing suppliers to take full responsibility for managing stocks and deliveries. Suppliers' performance is measured according to how often inventory is shipped to the retailer, and how often customers are unable to purchase the product because it is out of stock. This emerging trend also implies that suppliers are absorbing a large part of the inventory and delivery costs and, therefore, must plan delivery programs including delivery frequency to ensure that the inherent costs are minimized. With the idea to incorporate this shift in focus, this paper looks at the problem facing the supplier who wants quicker replenishment at lower cost. In particular, we present a model that seeks the best trade-off among inventory investment, delivery rates, and permitting shortages to occur, given some random demand pattern for the product. The process generating demand consists of two components: one is deterministic and the other is random. The random part is assumed to follow a compound Poisson process. Furthermore, we assume that the supplier may fail to meet uniform shipping schedules, and, therefore, uncertainty is present in delivery times. The solution to this transportationinventory problem requires determining jointly delivery rates and stock levels that will minimize transportation, inventory, and shortage costs. Several numerical results are presented to give a feel of the optimal policy's general behavior. [source]

On the (S , 1, S) lost sales inventory model with priority demand classes

NAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 6 2002
R. Dekker
Abstract In this paper an inventory model with several demand classes, prioritised according to importance, is analysed. We consider a lot-for-lot or (S , 1, S) inventory model with lost sales. For each demand class there is a critical stock level at and below which demand from that class is not satisfied from stock on hand. In this way stock is retained to meet demand from higher priority demand classes. A set of such critical levels determines the stocking policy. For Poisson demand and a generally distributed lead time, we derive expressions for the service levels for each demand class and the average total cost per unit time. Efficient solution methods for obtaining optimal policies, with and without service level constraints, are presented. Numerical experiments in which the solution methods are tested demonstrate that significant cost reductions can be achieved by distinguishing between demand classes. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 593,610, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10032 [source]

Optimal control of work-in-process inventory of a two-station production line,

OPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 3 2010
A. Kokangul
Abstract Most production lines keep a minimal level of inventory stock to save storage costs and buffer space. However, the random nature of processing, breakdown, and repair times can significantly affect the efficiency of a production line and force the stocking of work-in-process inventory. We are interested in the case when starvation and blockage are preferentially avoided. In this study, a mathematical model has been developed using asymptotic approximation and simulation that provides asymptotic results for the expected value and the variance of the stock level in a buffer as a function of time. In addition, the functional relationship between buffer capacity and the first stopping time caused by starvation or blockage has been determined. Copyright © 2009 John Wiley & Sons, Ltd. [source]

The Dog That Did Not Bark: Insider Trading and Crashes

THE JOURNAL OF FINANCE, Issue 5 2008
JOSE M. MARIN
ABSTRACT This paper documents that at the individual stock level, insiders' sales peak many months before a large drop in the stock price, while insiders' purchases peak only the month before a large jump. We provide a theoretical explanation for this phenomenon based on trading constraints and asymmetric information. A key feature of our theory is that rational uninformed investors may react more strongly to the absence of insider sales than to their presence (the "dog that did not bark" effect). We test our hypothesis against competing stories, such as insiders timing their trades to evade prosecution. [source]

Optimal material control in an assembly system with component commonality

NAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 5 2001
Narendra Agrawal
Abstract Allocation of scarce common components to finished product orders is central to the performance of assembly systems. Analysis of these systems is complex, however, when the product master schedule is subject to uncertainty. In this paper, we analyze the cost,service performance of a component inventory system with correlated finished product demands, where component allocation is based on a fair shares method. Such issuing policies are used commonly in practice. We quantify the impact of component stocking policies on finished product delays due to component shortages and on product order completion rates. These results are used to determine optimal base stock levels for components, subject to constraints on finished product service (order completion rates). Our methodology can help managers of assembly systems to (1) understand the impact of their inventory management decisions on customer service, (2) achieve cost reductions by optimizing their inventory investments, and (3) evaluate supplier performance and negotiate contracts by quantifying the effect of delivery lead times on costs and customer service. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48:409,429, 2001 [source]

Oil Prices and Stocks in the Second Quarter of 2004

OPEC ENERGY REVIEW, Issue 1 2004
OPEC Secretariat
Notwithstanding forecasting difficulties, the oil supply and demand balance has proved to be a good indicator of the state of the market and stock levels, which, in turn, influence price behaviour. In periods where OECD commercial stock levels lie within a certain range, currently around 2,450,2,650 million barrels, the range of prices is larger than when stock levels are very high or very low. In both the latter extreme situations, prices are prone to rapid movements, undermining market stability. Other factors, of course, also influence price fluctuations. The general opinion among regularly published oil market reports points to the inevitability of a higher-than-normal build in stocks in the second quarter of 2004. If the resulting surplus is not handled in a timely and effective manner, there is likely to be excessive downward pressure on prices, which, if left unattended, would lead to a protracted spell of volatility. [source]

STOCK LEVELS AND DELIVERY RATES IN VENDORMANAGED INVENTORY PROGRAMS

PRODUCTION AND OPERATIONS MANAGEMENT, Issue 1 2001
BEN A. CHAOUCH
Using the latest information technology, powerful retailers like Wal-Mart have taken the lead in forging shorter replenishment-cycles, automated supply systems with suppliers. With the objective to reduce cost, these retailers are directing suppliers to take full responsibility for managing stocks and deliveries. Suppliers' performance is measured according to how often inventory is shipped to the retailer, and how often customers are unable to purchase the product because it is out of stock. This emerging trend also implies that suppliers are absorbing a large part of the inventory and delivery costs and, therefore, must plan delivery programs including delivery frequency to ensure that the inherent costs are minimized. With the idea to incorporate this shift in focus, this paper looks at the problem facing the supplier who wants quicker replenishment at lower cost. In particular, we present a model that seeks the best trade-off among inventory investment, delivery rates, and permitting shortages to occur, given some random demand pattern for the product. The process generating demand consists of two components: one is deterministic and the other is random. The random part is assumed to follow a compound Poisson process. Furthermore, we assume that the supplier may fail to meet uniform shipping schedules, and, therefore, uncertainty is present in delivery times. The solution to this transportationinventory problem requires determining jointly delivery rates and stock levels that will minimize transportation, inventory, and shortage costs. Several numerical results are presented to give a feel of the optimal policy's general behavior. [source]

Availability of antidotes for the treatment of acute poisoning in Queensland public hospitals

AUSTRALIAN JOURNAL OF RURAL HEALTH, Issue 2 2010
Lisa M. Nissen
Abstract Objective:,To determine the sufficiency of stock levels of 13 antidotes in Queensland hospitals. Design:,A self-report survey was sent to 128 Queensland hospitals with acute care facilities. The stock level of the following antidotes was determined: acetylcysteine, anti-digoxin Fab antibodies (digibind), atropine, calcium gluconate, cyanokit, desferrioxamine, flumazenil, glucagon, intravenous ethanol, methylene blue, naloxone, pralidoxime and pyridoxine. Other factors sampled were bed capacity, rural, remote and metropolitan areas classification, use of formal stock reviews by pharmacists or nurses, existence of formal borrowing agreements with other facilities for non-stocked antidotes, distance to the nearest referral hospital and time taken to transfer antidotes from another hospital. Participants:,Pharmacists or nurses responsible for maintaining antidote stocks in Queensland hospitals. Main outcome measures:,Proportions of hospitals with sufficient antidote stock to treat a 70-kg adult for four or more hours using previously published guidelines. Results:,Survey response rate was 73.4%. No hospital had sufficient stock of all 13 antidotes. The proportion of hospitals with sufficient stocks varied from 0% (pyridoxine) to 68.1% (acetylcysteine). Larger hospitals had a higher frequency of sufficient antidote stocks. Only 16% of hospitals claimed to be able to acquire an antidote from another facility within 30 min. Conclusions:,Most Queensland hospitals stocked some important antidotes, but few had sufficient stock to treat a 70-kg patient or acquire an antidote within the recommended time frame of 30 min. Specific antidote stocking guidelines might be required for Queensland hospitals. A formalised program for stock rotation with rural facilities should be explored. [source]