Previous studies show that the concept of L♮-convexity is helpful in characterizing the optimal policy for some inventory models with positive leadtimes. Such examples include the lost-sales inventory model by Zipkin (2008). On the structure of lost-sales inventory models. Operations Research,...

Soil, atmosphere, water and quality of agricultural product constitute the content of land ecological quality. Cixi City, through survey pilot project of basic farmland quality, carried out high precision soil geochemical survey and survey of agricultural products, irrigation water and air...