Optimal ordering and pricing in a quick response system

Cataloged from PDF version of article.Quick response systems enable retailers to estimate customer demand more accurately, and improve stocking decisions for perishable products with uncertain demand. Retailers place separate orders for a product at two different times before the selling season. Following the initial order, additional market information is obtained, and the second-order amount is decided based on an improved demand forecast. In some cases, purchase cost associated with the second order is uncertain, and demand for the product during the season depends on the selling price. We present a solution procedure for finding the optimal order quantity and selling price in this setting. We also study the case where any desired portion of the initial order can be cancelled after updating the demand forecast. In the numerical study. the optimal price is observed to be relatively insensitive to changes in demand variability. (C) 2009 Elsevier B.V. All rights reserved

Inventory and pricing decisions in a single-period problem involving risky supply

Cataloged from PDF version of article.We explore an extension of the single-period (newsboy) inventory problem when supply is uncertain. We look into the negotiations between a newsvendor (retailer) and a manufacturer when there is competition from a second supplier. There is a chance that the second supplier will not be able to deliver the product. The retailer can maximize his expected profit by optimally allocating his order between the two suppliers. The retailer’s ordering problem is analyzed in conjunction with the manufacturer’s related pricing problem. The effects of demand and supply uncertainties on the optimal decisions of the parties are explored using numerical examples. We also explore extension of the retailer’s problem to the cases of order cancellation, price-dependent demand, and demand-dependent supply availability. & 2008 Elsevier B.V. All rights reserve

Multi-item quick response system with budget constraint

Cataloged from PDF version of article.Quick response mechanisms based on effective use of up-to-date demand information help retailers to reduce their inventory management costs. We formulate a single-period inventory model for multiple products with dependent (multivariate normal) demand distributions and a given overall procurement budget. After placing orders based on an initial demand forecast, new market information is gathered and demand forecast is updated. Using this more accurate second forecast, the retailer decides the total stocking level for the selling season. The second order is based on an improved demand forecast, but it also involves a higher unit supply cost. To determine the optimal ordering policy, we use a computational procedure that entails solving capacitated multi-item newsboy problems embedded within a dynamic programming model. Various numerical examples illustrate the effects of demand variability and financial constraint on the optimal policy. It is found that existence of a budget constraint may lead to an increase in the initial order size. It is also observed that as the budget available decreases, the products with more predictable demand make up a larger share of the procurement expenditure. & 2012 Elsevier B.V. All rights reserved

Joint economic design of EWMA control charts for mean and variance

Cataloged from PDF version of article.Control charts with exponentially weighted moving average (EWMA) statistics (mean and variance) are used to jointly monitor the mean and variance of a process. An EWMA cost minimization model is presented to design the joint control scheme based on pure economic or both economic and statistical performance criteria. The pure economic model is extended to the economic-statistical design by adding constraints associated with in-control and out-of-control average run lengths. The quality related production costs are calculated using Taguchi's quadratic loss function. The optimal values of smoothing constants, sampling interval, sample size, and control chart limits are determined by using a numerical search method. The average run length of the control scheme is computed by using the Markov chain approach. Computational study indicates that optimal sample sizes decrease as the magnitudes of shifts in mean and/or variance increase, and higher values of quality loss coefficient lead to shorter sampling intervals. The sensitivity analysis results regarding the effects of various inputs on the chart parameters provide useful guidelines for designing an EWMA-based process control scheme when there exists an assignable cause generating concurrent changes in process mean and variance. (C) 2006 Elsevier B.V. All rights reserved

Economic design of EWMA control charts based on loss function

Cataloged from PDF version of article.For monitoring the stability of a process, various control charts based on exponentially weighted moving average (EWMA) statistics have been proposed in the literature. We study the economic design of EWMA-based mean and dispersion charts when a linear, quadratic, or exponential loss function is used for computing the costs arising from poor quality. The chart parameters (sample size, sampling interval, control limits and smoothing constant) minimizing the overall cost of the control scheme are determined via computational methods. Using numerical examples, we compare the performances of the EWMA charts with Shewhart X and S charts, and investigate the sensitivity of the chart parameters to changes in process parameters and loss functions. Numerical results imply that rather than sample size or control limits, the users need to adjust the sampling interval in response to changes in the cost of poor quality. © 2008 Elsevier Ltd. All rights reserved

Pediatric Acupuncture: A Review of Clinical Research

Practiced in China for more than 2000 years, acupuncture has recently gained increased attention in the United States as an alternative treatment approach for a variety of medical conditions. Despite its growing prevalence and anecdotal reports of success among pediatric populations, few empirically based studies have assessed the efficacy of acupuncture for children and adolescents. This article presents a review of the current literature, including a systematic appraisal of the methodological value of each study and a discussion of potential benefits and adverse effects of acupuncture. While acupuncture holds great promise as a treatment modality for diverse pediatric conditions, a significant amount of additional research is necessary to establish an empirical basis for the incorporation of acupuncture into standard care

Capacity reservation under supply uncertainty

Cataloged from PDF version of article.Shortages of input materials and components used in the production process often adversely influence sales of manufacturing firms. Manufacturers can guarantee delivery of the inputs by initiating capacity reservation arrangements with their suppliers. We study a multi-period capacity reservation contract between a manufacturer and a long-term supplier when there is uncertainty about the quantity of an input item available in the spot market. The contract requires the manufacturer to pay a fixed amount to the supplier at each period. In return, the supplier guarantees availability of the input up to a predetermined level of volume. The manufacturer can also meet some of input needs from a spot market, which may exist in the form of a B2B electronic exchange. Optimal inventory policy for the manufacturer in this dual supplier environment is derived analytically. Numerical examples are used to explore the strategies of the manufacturer and the supplier in certain and uncertain supply environments. We find that uncertain input markets lead to an increase in the share of inputs purchased in advance via long-term contracts. Capacity reservation contracts are shown to increase capacity utilization of the supplier compared to the traditional unit-price based supply contracts. 2005 Elsevier Ltd. All rights reserved

Effects Of Submental Surface Electrical Stimulation On Swallowing Kinematics In Healthy Adults: An Error-Based Learning Paradigm

Purpose: Hyoid bone and laryngeal approximation aid airway protection (laryngeal vestibule closure) while moving toward their peak superior and anterior positions during swallowing. Submental surface electrical stimulation (SES) is a therapeutic technique that targets the muscles that move the hyoid bone during swallowing. It is unknown whether submental SES only increases peak hyoid bone swallowing positions but not peak laryngeal swallowing positions, which could require faster or greater laryngeal movement to achieve adequate laryngeal vestibule closure. Method: We examined the effects of submental SES on hyo-laryngeal kinematics in 30 healthy adults who swallowed 50 times using an error-based learning paradigm. Results: Submental SES did not alter any hyo-laryngeal swallowing kinematic. However, submental SES significantly changed the starting position of the hyoid bone just prior to the swallow onset (more anterior; p = .003). On average, submental SES immediately prior to swallow onset can position the hyoid approximately 20% closer to its peak swallowing point. Conclusions: These findings indicate that electrical stimulation of the agonists for hyoid movement might not alter swallowing outcomes tested in this study. However, submental SES could have clinical utility by minimizing swallowing impairments related to reduced hyoid swallowing range of motion in individuals with dysphagia.Wo