The appearance of counterfeit medicines in supply chains is a global public health problem that may seriously affect patients. Counterfeit drugs do not meet quality standards and do not declare their real composition and/or source for the purposes of fraud. They may be generic or innovative, they may contain genuine constituents in a fake packaging, or wrong ingredients, or inactive ingredients...

Deterministic Economic Order Quantity EOQ models have been studied intensively in the literature, where the demand process is described by an ordinary differential equation, and the objective is to obtain an EOQ, which minimizes the total cost per unit time. The total cost per unit time consists of a “discrete” part, the setup cost, which is incurred at the time of ordering, and a “continuous” ...

The main purpose of this paper is to investigate the retailer’s optimal cycle time and optimal payment time under the supplier’s cash discount and trade credit policy within the economic production quantity (EPQ) framework. In this paper, we assume that the retailer will provide a full trade credit to his/her good credit customers and request his/her bad credit customers pay for the items as so...

Spacetime singularities have been discovered which are physically much weaker than those predicted by the classical singularity theorems. Geodesics evolve through them and they only display infinities in the derivatives of their curvature invariants. So far, these singularities have appeared to require rather exotic and unphysical matter for their occurrence. Here we show that a large class of ...

We review historical patterns of "economic geography" for the United States from the colonial period to the present day. The analysis is framed in terms of two geographic scales: regions and cities. The compelling reason for studying geographic areas of different scales is that models that explain the location of economic activities at one scale many not apply to other scales. We consider the p...

The main purpose of this paper wants to investigate the optimal retailer’s lot-sizing policy with two warehouses under partially permissible delay in payments within the economic order quantity (EOQ) framework. In this paper, we want to extend that fully permissible delay in payments to the supplier would offer the retailer partially permissible delay in payments. That is, the retailer must mak...

An order level inventory system for deteriorating items has been developed with demand rate as a ramp type function of time. The finite production rate is proportional to the demand rate and deterioration rate is time proportional. The unit production cost is inversely proportional to the demand rate. The model with no shortage case in inventory is first solved. The inventory shortage is discus...

While deterioration models consider the gradual reduction in quality and quantity of products over time, amelioration models assume the opposite. This paper is based on an earlier work by Hwang for finding an optimal economic order quantity solution for items subject to amelioration in a Weibull distribution. Hwang solved the problem with a graphical procedure. In this paper, a rigorous analyti...

Summery-EPQ Psychoticism (P) is thought to be fundamental to religiosity (Francis, 1992a), while Neuroticism (N), Extraversion (E) and Lie dimensions (L) are not consistently found to be associated with religious beliefs and behaviours. Among 6463 Anglican, Other Protestant and Catholic Australian twins (aged 17-88yr), we found that men and women who attended church regularly had low P and low ...

This paper deals with an integrated model for the joint determination of both economic production quantity (EPQ) and level of preventive maintenance (PM) for an imperfect production process. This process has a general deterioration distribution with increasing hazard rate. The effect of PM activities on the deterioration pattern of the process is modeled using the imperfect maintenance concept....