In real-world applications, costs for products are not deterministic: neither static nor dynamic. They actually tend to be non-stationary and cross-correlated. To overcome this drawback, there have been some efforts by researchers to extend the Wagner–Whitin algorithm to consider stochastic costs. However, they assume that the information of probability density function of random costs exists. ...

in future, soil erosion will be a great challenge for biosphere. if the soils today are notprotected carefully hunger crises all over the world will be widespread. the present article endeavorsto survey soil erosion process and approaches to prevent it. furthermore the article tries to review therelation between soil character and soil production capability shedding light on the effect of erosi...

Over the past three decades, the agricultural biotechnology sector has been characterized by rapid innovation, market consolidation, and a more exhaustive definition of property rights. The industry attributes consistently identified by the literature and important to this analysis include: (i) endogenous sunk costs in the form of expenditures on R&D; (ii) seed and agricultural chemical technol...

Local outputs for nationally available brands of packaged goods tend to be spatially concentrated, i.e., the same brand has high outputs in some regions, and low outputs in others. Curiously, such spatial concentration is very persistent despite direct competition between brands and a notable lack of product differentiation. It is shown that the stability of spatial concentration can be explain...

Over the past three decades, the agricultural biotechnology sector has been characterized by rapid innovation, market consolidation, and a more exhaustive definition of property rights. The industry attributes consistently identified by the literature and important to this analysis include: (i) endogenous sunk costs in the form of expenditures on R&D; (ii) seed and agricultural chemical technol...

Comparative advantage and trade costs shape the geography of cross-border supply chains and trade flows. To quantify these forces, we build a model of trade with sequential, multi-stage production that features technology differences both across and within individual production stages. We estimate technology and trade costs in the model via simulated method of moments, matching bilateral shipme...

This paper develops a search model to explain the long tail effect. Search targetibility or the quality of search is explicitly modeled. Consumers are searching for the right products within the right categories. Mainstream consumers are distinguished from long tail consumers in terms of the prevalence of consumer tastes in the population. We show that mainstream consumers enjoy higher utility ...

In the absence of a perfect risk adjustment scheme, cost sharing can reduce risk selection in community-rated health insurance markets. However, cost sharing also reduces incentives for efficiency. In this paper, we develop a model in which insurers determine the cost efficiency of health care. They have incentives for risk selection because there are two risk types which differ in their expect...

This study examines the impact of capital structure on agency costs in 211 non-financial Chinese listed firms for the period 1999-2001. There are two main findings. (1) Firms with high debt to asset ratio have high ratio of annual sales to total assets and high ratio of return-on-equity. If a firm has a high debt to asset ratio, creditors are much more concerned about the payment of interest an...