Some Comments on the Validity of EOQ Formula under Inflationary Conditions

In an earlier issue of Decision Sciences, Jesse, Mitra, and Cox [1] examined the impact of inflationary conditions on the economic order quantity (EOQ) formula. Specifically, the authors analyzed the effect of inflation on order quantity decisions by means of a model that takes into account both inflationary trends and time discounting (over an infinite time horizon). In their analysis, the authors utilized two models: Current-dollars model and Constant-dollars model. These models were derived, of course, by setting up a total cost equation in the usual manner then finding the optimum order quantity that minimizes the total cost. Jesse, Mitra, and Cox [1] found that EOQ is approximately the same under both conditions; with or without inflation. However, we disagree with the conclusion drawn by [2] and show that EOQ will be different under inflationary conditions, provided that the inflationary conditions are properly accounted for in the formulation of the total cost model.     

An algorithm to dynamically adjust the number of Kanbans in stochastic processing times and variable demand environment

In a real-life environment, the just-in-time JIT system is subjected to various types of uncertainties such as stochastic processing times and variable demand. Since, JIT was only meant to operate in a deterministic environment, its performance is seriously affected by variations in processing times and demand. In this paper, a newly developed Kanban system is presented which uses an algorithm to dynamically and systematically manipulate the number of Kanbans in order to offset the blocking and starvation caused by the said uncertainties during a production cycle. The new system is termed a flexible Kanban system FKS . The steps of the algorithm are detailed and the effectiveness of FKS is demonstrated using an example model. For the example model, the solution procedure, results and a discussion are presented.     

Customization: Impact on Product and Process Performance

Manufacturing capability has often been viewed to be a major obstacle in achieving higher levels of customization. Companies follow various strategies ranging from equipment selection to order process management to cope with the challenges of increased customization. We examined how the customization process affects product performance and conformance in the context of a design‐to‐order (DTO) manufacturer of industrial components. Our competing risk hazard function model incorporates two thresholds, which we define as mismatch and manufacturing thresholds. Product performance was adversely affected when the degree of customization exceeded the mismatch threshold. Likewise, product conformance eroded when the degree of customization exceeded the manufacturing threshold. Relative sizes of the two thresholds have management implications for the subsequent investments to improve customization capabilities. Our research developed a rigorous framework to address two key questions relevant to the implementation of product customization: (1) what degrees of customization to offer, and (2) how to customize the product design process.     

Reconciling situational social psychology with virtue ethics

For the past four decades, debate has occurred in respect of situational social psychology and virtue ethics. This paper attempts to reconcile this debate. Situationists propose a fragmentation theory of character (each person has a whole range of dispositions, each of which has a restricted situational application) and do not subscribe to a regularity theory of character (behaviour is regulated by long‐term dispositions). In order to support this view, they cite a number of experiments. It is proposed that the substantive claims made by situationist social psychologists, for the most part, do not undermine or disagree with an Aristotelian virtue ethics perspective, but stem from a misunderstanding of concepts of moral character, faulty conclusions and generalizations in respect of experimental results. Situationists take a narrow view of character and morality. Evidence from organizational behaviour and managerial research literature supports the view that both situational (organizational) features and inner characteristics (including virtues) are powerful influences and determinants of morally upright and morally deviant behaviour. The role of practical judgement in bridging these views is discussed. As a way forward in reconciling situational social psychology with virtue ethics, the paper proposes an Aristotelian–Thomistic framework to overcome some of the problems associated with inadequate regulative ideals in building a normative moral theory.     

Regional Computable General Equilibrium models: A review

Computable General Equilibrium (CGE) models are very popular for analyzing a wide range of policy issues. CGE applications vary from estimating the welfare impact of tax reform and alternative energy policies to the effect of foreign trade reforms, labour markets and employment. CGE models are commonly developed at the country level; however, modified versions of CGE, so called Regional CGE (RCGE) models, can be used at subnational disaggregation to examine impacts studied at the national counterparts on a specific region. RCGE models have grown in popularity as an alternative to the Input-Output (I-O) models, which are regularly used for regional analysis. RCGE models can provide comprehensive information, which make them more desirable analytical models for many researchers. Yet, RCGE models have not yet become a “go-to” for governmental policy practitioners when they are developing regional public policies. This paper reviews the current state of regional CGE models, describes their features, contributions and limitations and surveys some applications of the main three classes of RCGE models: region-specific, bottom-up, and top-down models. This paper concludes that the applications of RCGE are quite variable and flexible, with a new and more complex type of application to be developed with the advancement of computation economics. The paper offers recommendations on the micro, meso and macro conditions that are necessary to increase policy practitioners’ utilization of RCGE models.     

A TWO-PHASE SAMPLING ESTIMATOR IN SAMPLE SURVEYS

A two-phase sampling estimator of the ratio-type for estimating the mean of a finite population, has been considered where the value of ρC_y/C_x can be guessed or estimated in advance. Here C_y and C_x denote respectively the coefficients of variation of the characteristic under study, y, and the auxiliary characteristic x and ρ denotes the coefficient of correlation between y and x. When the value of ρC_y/C_x is guessed or estimated exactly, the estimator has a smaller large-sample variance compared with either an ordinary ratio estimator or an ordinary linear regression estimator in two-phase sampling in the case where the first-phase sample is drawn independently from the second-phase sample. If the sample at the second phase is a subsample of the first-phase sample, the estimator has variance equal to that of the linear regression estimator. The largest value of the difference between the assumed value and the actual value of ρC_y/C_x has been obtained so as not to result in the variance of the estimator being larger than the variances of either an ordinary ratio estimator or an ordinary linear regression estimator.     

Modeling a low-carbon garment supply chain

This article attempts to introduce indirect carbon emission and trade-credit concept in a network optimisation model for sustainable supply chain. The proposed model optimises total cost, total direct carbon emission, total indirect emission in the form of embodied carbon footprint of the raw material and total trade-credit amount over the purchased item in a supply chain. The model calculates the total cost by considering purchasing cost, logistics cost, handling cost and manufacturing cost. It attempts to measure the direct emission involved in manufacturing and logistics operations. The model has the capability to consider dissimilar trucks used for transportation according to their operating cost and carbon emission. Multi-objective goal programming is applied to deal with four objectives to find a tradeoff among these objectives. The result suggests that managers should capture the direct as well as the indirect emission which helps in arriving at appropriate strategy for a sustainable supply chain. The effectiveness of the proposed model is demonstrated through a case of a garment supply chain. This model also supports in deciding appropriate goal for carbon emission, supply chain costs, etc.     

A class of estimators using auxiliary information in sample surveys

A large class of estimators is considered for the mean of a finite population using information on an auxiliary variable. It is shown that members of this class of estimators are asymptotically no more efficient than the linear regression estimator.     

Environmental forecasting and non-profit professional organizations

To undertake any kind of realistic planning activity, it is useful to have a long-term environmental forecast which provides the planner with an overall perspective. The planner will be functioning over the next decade in a very dynamic, complex and challenging political, economic, technological and social environment, and will require very effective planning efforts to cope with such changing environment. This article presents an approach and methodology that a planner could use in his/her organization's planning process. To the best of our knowledge, very few organizations—profit and non-profit oriented—undertake a formal long-term environmental forecast. This article might encourage several planners to examine this area of long range planning in their respective organizations. The long- term environmental forecasting approach presented in this article could be applied by planners in all types of organizations—small or large, profit oriented or non-profit oriented, old or new. This article, however, is based on a study which the authors did for a non-profit organization.