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 area of two different scales is that models that explain location of economic activities at one scale may not apply to other scales. We consider the proce...

Within the economic order quantity (EOQ) framework, the main purpose of this paper is to investigate the retailer’s optimal replenishment policy under permissible delay in payments. All previously published articles dealing with optimal order quantity with permissible delay in payments assumed that the supplier only offers the retailer fully permissible delay in payments if the retailer ordered...

In order to solve the problem of difficult gas extraction in coal mine, a method from seam by interval hydraulic flushing is put forward. Based on occurrence conditions 7609 working face Wuyang Coal Mine, numerical simulation research drainage ordinary drilling and was carried out using COMSOL software. The results show that with increase quantity, effective radius also increases. 0.5 m, 1.0 1....

Among the assumptions of the classical economic order quantity (EOQ) model is that all units that are purchased (or produced) are of perfect quality. However, this is frequently unrealistic since production processes deteriorate resulting in the production of defective products requiring rework. Some recent studies suggest that production systems performance might be improved by applying the fi...

The traditional inventory of the economic order quantity model assumes perfect items in an ordered lot and an infinite replenishment rate. However, such conditions are rare in actual production environments. Additionally, most studies of this problem have only considered suppliers offering the wholesaler a grace period. In practice, wholesalers often extend a fixed credit period to downstream c...

Cárdenas-Barrón (2010) applied algebraic methods to EOQ and EPQ models without referring to differential equations, allowing researchers without backgrounds in calculus to understand inventory models with ease. In this note, we point out that the derivation for EPQ model can be obtained by a transformation of the EOQ model and then we provide a further simplification of his approach such that f...

In general, a supplier/retailer frequently offer trade credit to stimulate their respective sales. The main purpose of this paper is to investigate the optimal supplier/retailer’s replenishment decisions under two levels of trade credit policy within the economic order quantity (EOQ) framework. This paper deals with the supplier/retailer’s inventory replenishment problem under two levels of tra...