generally ordering policies are done by two methods, including fix order quantity (foq) and fix order period (fop). these methods are static and either the quantity of ordering or the procedure of ordering is fixing in throughout time horizon. in real environments, demand is varying in any period and may be considered as uncertainty. when demand is variable in any period, the traditional and st...

background: infant mortality is one of the main indexes in the assessment of a society's access to the primary health care ser­vices. many factors are involved in this regard. the present study aimed at determining the structural association be­tween socio-economic variables and the rate of infant mortality rate. methods: the required data and information were collected from the multiple indica...

BACKGROUND Data processing contributes a non-trivial proportion to total research costs, but documentation of these costs is rare. This paper employed a priori cost tracking for three posture assessment methods (self-report, observation of video, and inclinometry), developed a model describing the fixed and variable cost components, and simulated additional study scenarios to demonstrate the ut...

Research of common stock offerings finds that the negative impact of issuance expenses can account for over three-fifths of the fall in the announcement period returns. Given the importance of issue costs, we extend the research by offering a model to estimate expected values for issue costs. This model can be used to generate the expected fall in stock value resulting from issue costs. We also...

wind power generation is variable and uncertain. in the power systems with high penetration of wind power, determination of equivalent operating reserve is the main concern of systems operator. in this paper, a model is proposed to determine operating reserves in simultaneous market clearing of energy and reserve by stochastic programming based on scenarios generated via monte carlo simulation ...

Abstract The Hierarchical Windy Postman Problem (HWPP) is an arc routing problem in which order relation imposed on the arcs/edges of graph, and one has to pass through each edge at least once while adhering hierarchical priority relations. tour starts from ends a specific node aim minimize length tour. We consider variant HWPP (i) precedence hierarchies linear edges within hierarchy are connec...

Abstract High crop densities are valuable to increase weed suppression, but growers might be reluctant implement this practice due increased seed cost. Because it is also possible lower planting in areas with no or low interference risk, the area allocated each density must optimized considering cost and productivity per plant. In study, growth yield of maize ( Zea mays L.), cotton Gossypium hi...