Ram Ramesh 2 - Academia.edu (original) (raw)
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Papers by Ram Ramesh 2
European Journal of Operational Research, 2000
A major cost element in the logistics of distributed warehousing is transportation cost. In most ... more A major cost element in the logistics of distributed warehousing is transportation cost. In most practical systems, the transportation costs are volume-dependent. The unit transportation costs are usually determined dierentially among intervals of shipment volumes. While the unit cost is constant over an interval, it follows a stepwise declining pattern from an interval to the next higher interval of shipment volumes. This structure is analogous to that of quantitydiscounted inventory systems. We consider a single-product, serial warehousing system operating under the dierential transportation costs and the traditional holding and ordering costs. External demand occurs at the ®nal stage at a constant continuous rate. Demand must be met on time over an in®nite horizon under continuous review. The objective is to determine the ordering lot size for each warehouse such that the long-run average cost is minimized. We model the above problem and establish its structural properties. We ®rst consider two-level dierential transportation cost structures and develop ecient algorithms to obtain a best integer ratio and optimal powers-of-two policies. Next, we consider multilevel cost structures and develop a hypercube characterization of the solution space. Ecient algorithms to yield a best integer ratio and powers-of-two policies using the hypercube model and a relaxation approach using the two-level model are developed. Extensive computational studies with the algorithms reveal that the proposed modeling and algorithmic approach is both viable and ecient in solving practical distribution problems. Conclusions and direction for future research are presented.
Applied Artificial Intelligence, 1992
An important philosophy of quality control due to Taguchi rests on the belief that, once quality ... more An important philosophy of quality control due to Taguchi rests on the belief that, once quality is designed into the product and the process, very little inspection is necessary. Taguchi evaluates quality in terms of costs incurred, including inspection and adjustment costs apart from quality loss. Using these costs, he determines an optimal interval for periodic inspection of products. At
European Journal of Operational Research, 2000
A major cost element in the logistics of distributed warehousing is transportation cost. In most ... more A major cost element in the logistics of distributed warehousing is transportation cost. In most practical systems, the transportation costs are volume-dependent. The unit transportation costs are usually determined dierentially among intervals of shipment volumes. While the unit cost is constant over an interval, it follows a stepwise declining pattern from an interval to the next higher interval of shipment volumes. This structure is analogous to that of quantitydiscounted inventory systems. We consider a single-product, serial warehousing system operating under the dierential transportation costs and the traditional holding and ordering costs. External demand occurs at the ®nal stage at a constant continuous rate. Demand must be met on time over an in®nite horizon under continuous review. The objective is to determine the ordering lot size for each warehouse such that the long-run average cost is minimized. We model the above problem and establish its structural properties. We ®rst consider two-level dierential transportation cost structures and develop ecient algorithms to obtain a best integer ratio and optimal powers-of-two policies. Next, we consider multilevel cost structures and develop a hypercube characterization of the solution space. Ecient algorithms to yield a best integer ratio and powers-of-two policies using the hypercube model and a relaxation approach using the two-level model are developed. Extensive computational studies with the algorithms reveal that the proposed modeling and algorithmic approach is both viable and ecient in solving practical distribution problems. Conclusions and direction for future research are presented.
Applied Artificial Intelligence, 1992
An important philosophy of quality control due to Taguchi rests on the belief that, once quality ... more An important philosophy of quality control due to Taguchi rests on the belief that, once quality is designed into the product and the process, very little inspection is necessary. Taguchi evaluates quality in terms of costs incurred, including inspection and adjustment costs apart from quality loss. Using these costs, he determines an optimal interval for periodic inspection of products. At