In this paper, we develop a procedure for selecting a supplier. Suppliers are characterized by their lead time, price and quality (random yield). Each purchased item is acceptable with a given probability and independent of the others. We assume the demands are deterministic with no set-up cost and backordering is allowed. For each supplier, an optimal ordering policy is developed. We prove the...

in order to evaluate the efficiency of empirical competition models for simulation of sugar beet (beta vulgaris l.) yield at interference with redroot pigweed (amaranthus retroflexus l.), a factorial experiment based on randomized complete block design with three replications was carried out. factors were weed densities (d1=1, d2= 4, d3= 8, d4=12 and d5=16 plants m-1 of row) and relative time o...

abstract in this study, impact of climate change on net irrigation requirement (in) and yield of wheat using cgcm3 climate projection model, one of the aogcm models, in behshahr area is evaluated. changes in temperature and precipitation were simulated run under the ipcc scenario a2 for 2011-2040, 2041-2070 and 2071-2100 periods. this work was done by using statistical and proportional downscal...

rainfed wheat is the main source of staple food for people in the developing countries. various factors contribute to and affect the production of this crop. the aim followed in the present study was to develop a model to estimate rainfed wheat grain yield as based on physico-chemical properties of the soil. therefore, wheat grain yield and soil physico-chemical properties were separately deter...

an analysis of the stages of crop growth presents an important step in the improvement of production management. through growth analysis, planning for planting systems, fertilization, pruning operations, harvest time as well as obtaining economical yield can be more accessible. therefore, a development of mathematical models simulating plant growth would be helpful in improving crop management,...

soil erosion is undoubtedly one of the most important problems in natural areas and has a devastating impact on grassland ecosystems. the present study was conducted to assess the ability of rangeland hydrology and erosion model for estimating sediment yield on rangeland’s hill slopes in dry regions at shahid noori paired watershed of kakhk. rhem is a mathematical, distribution and physical mod...