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

Diyabetik hastaların eğitim ihtiyaçlarının değerlendirilmesi

Objective: Our study aimed to assess the role of pre-graduate pharmacy students’ participation in a diabetic education program on improving diabetic self-care. Material and Method: This study included both a cross-sectional and a longitudinal follow-up. Altinbas University fifth-year pharmacy students gathered relevant information from diabetic patients that visited community pharmacies, under the supervision of their instructor pharmacist. The participants filled out the diabetic self-care scale on their first visit before they were given the education. Patients refilled the same self-care questionnaire after three months. Statistical package for the social science (SPSS) 26 was used for all statistical analysis. Result and Discussion: The study comprised 86 diabetic patients. The second questionnaire results showed significant improvement in all patients. The total diabetic self-care scale scores were improved remarkably after the training session. HbA1c and BMI values decreased significantly. An educational program can improve diabetic self-care and diabetic outcomes. Active participation of final year pharmacy students in patient care can also improve pharmacists' participation and contribution to patient care delivery.Amaç: Çalışmamız, son sınıf eczacılık öğrencilerinin diyabetik bir eğitim programına katılımlarının diyabetik öz bakımın iyileştirilmesindeki rolünü değerlendirmeyi amaçlamıştır. Gereç ve Yöntem: Bu çalışma hem kesitsel hem de boylamsal bir takip içermektedir. Altınbaş Üniversitesi eczacılık beşinci sınıf öğrencileri, serbest eczaneleri ziyaret eden diyabet hastalarının gerekli bilgilerini sorumlu eczacılarının gözetiminde topladı. Katılımcılar diyabetik öz bakım ölçeğini doldurduktan sonra kendilerine eğitim verildi. Hastalar aynı öz bakım anketini üç ay sonra tekrar doldurdu. Tüm istatistiksel analizler için sosyal bilimler için istatistiksel paket (SPSS) 26 kullanıldı. Sonuç ve Tartışma: Çalışmaya 86 diyabetik hasta dahil edildi. İkinci anket sonuçları tüm hastalarda anlamlı iyileşme gösterdi. Toplam diyabetik öz bakım ölçeği puanları, eğitim seansından sonra önemli ölçüde iyileşti. HbA1c ve BMI değerlerinde anlamlı azalma oldu. Bir eğitim programı diyabetik öz bakımı ve diyabetik sonuçları iyileştirebilir. Eczacılık son sınıf öğrencilerinin hasta bakımına aktif katılımı, eczacıların hasta bakımı sunumuna katılımını ve katkısını da artırabilir

Üniversite Öğrencilerinin Finansal Okuryazarlığı: Balıkesir Üniversitesi Örneği

Bu çalışma, üniversite öğrencilerinin finansal bilgi düzeyi ile sosyo-ekonomik ve sosyo-demografik özellikleri arasındaki ilişkiyi belirlemeyi amaçlamıştır. Araştırmanın örneklemini 2050 öğrenci oluşturmuş olup, çalışma genel tarama (survey) modeli kullanılarak gerçekleştirilmiştir. Verilerin analizinde parametrik testler (t-testi ve ANOVA) ve parametrik olmayan testler (Mann, Whitney U ve Kruskal-Wallis H) kullanılmıştır. Çalışma sonuçları, öğrencilerin finansal okuryazarlık düzeyinin düşük olduğunu ortaya koymuştur. Cinsiyet, yaş, öğretim türü, eğitim alanı ve düzeyi, akademik başarı, çalışma hayatına ait deneyim, aile eğitim ve gelir düzeyi ve kredi kartı sahipliğinin finansal okuryazarlık seviyesi açısından temel belirleyiciler olduğu sonucuna ulaşılmıştır. Ayrıca, televizyonun finansal okuryazarlık üzerinde diğer finansal bilgi kaynaklarından daha etkin olduğu saptanmıştır. Bu kapsamda, finansal okuryazarlığa ilişkin derslerin ve uygulama çalışmalarının müfredata yerleştirilmesinin öğrencilerin finansal okuryazarlık düzeyini artırtabileceği dikkate alınmalıdır

Coordination of staffing and pricing decisions in a service firm

Customer demand is sensitive to the price paid for the service in many service environments. Using queueing theory framework, we develop profit maximization models for jointly determining the price and the staffing level in a service company. The models include constraints on the average waiting time and the blocking probability. We show convexity of the single-variable subproblem under certain plausible assumptions on the demand and staffing cost functions. Using numerical examples, we investigate the sensitivity of the price and the staffing level to changes in the marginal service cost and the user-specified constraint on the congestion measure. Copyright © 2008 John Wiley & Sons, Ltd

Stochastics and Statistics Joint economic design of EWMA control charts for mean and variance

Abstract 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

Univariate X̄ control charts for individual characteristics in a multinormal model

The early work on multivariate statistical process control was built upon Hotelling's T2 control chart which was developed to simultaneously monitor the means of correlated quality variables. This chart, however, has a drawback, namely, the problem of identifying the responsible variable(s) when an out-of-control signal occurs. One alternative is to use a separate X̄ control chart for each individual characteristic with equal risks, based on Bonferroni inequality. In this study, we show that, from an economic perspective, it may be desirable to have unequal type I risks for the individual charts, because of different inspection and restoration costs associated with each variable. We obtain their risk ratios, which are measures of relative importance of the variables monitored. Then, based on these risk ratios, we develop computer algorithms for finding the exact control limits for individual variables from a multinormal distribution, in the sense that the overall type I risk of the charts is equal to the desired value. Numerical studies show that the proposed methods give optimal or near-optimal results from an economic as well as statistical point of view