We consider inventory systems of “perishable” goods. Perishable goods cannot be carried from one period to another. Examples of perishable goods include newspaper, Christmas tree, and many grocery items like milk and banana. Here, a period could be one day, or one week, or any time frame that is appropriate in the application context. Suppose that a retailer sells a particular perishable produc...

The radial distribution function is a characteristic geometric quantity of a point set in Euclidean space that reflects itself in the corresponding diffraction spectrum and related objects of physical interest. The underlying combinatorial and algebraic structure is well understood for crystals, but less so for non-periodic arrangements such as mathematical quasicrystals or model sets. In this ...

In this paper the periodic solutions of fourth order delay differential equation of the form $ddddot{x}(t)+adddot{x}(t)+f(ddot{x}(t-tau(t)))+g(dot{x}(t-tau(t)))+h({x}(t-tau(t)))=p(t)$  is investigated. Some new positive periodic criteria are given.  

The EOQ and EPQ models with linear and fixed backorder costs are newly analyzed and all formulae are proven using only algebra. Two cases are identified, where backorders should and should not be allowed. The results are shown to include several known special cases. r 2004 Elsevier B.V. All rights reserved.

In many industries, customers are offered free shipping whenever an order placed exceeds a minimum quantity specified by suppliers. This allows the suppliers to achieve economies of scale in terms of production and distribution by encouraging customers to place large orders. In this paper, we consider the optimal policy of a retailer who operates a single-product inventory system under periodic...

Economic order/production quantity (EOQ/EPQ) models have generally been presented for manufacturing products. Incorporating some important features of a specific category of products, different EOQ/EPQ models have been proposed in literature. This study proposes a new class of inventory models, i.e. a model for a specific type of inventory items: growing items. Poultry and livestock are good ex...

Economic Order Quantity (EOQ) model has been extended. We formulate EOQ model as a calculus of variations. This new extended problem is a simple optimal control problem with an unknown initial state. By solving this problem we generalize EOQ formula [1].