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Successful supply chain management necessitates an effective sourcing strategy to combat uncertainties in both supply and demand. In particular, supply disruption results in excessive downtime of production resources, upstream and downstream supply chain repercussions, and eventually a loss in the market value of the firm. In this paper we analyze single period, single product sourcing decisions under demand uncertainty. Our approach integrates product prices, supplier costs, supplier capacities, historical supplier reliabilities and firm specific inventory costs. A unique feature of our approach is the integration of a firm specific supplier diversification function. We also extend our analysis to examine the impact of minimum supplier order quantities. Our results indicate that single sourcing is a dominant strategy only when supplier capacities are large relative to the product demand and when the firm does not obtain diversification benefits. In other cases, we find that multiple sourcing is an optimal sourcing strategy. We also characterize a non-intuitive trade-off between supplier minimum order quantities, costs, and supplier reliabilities. Finally, we examine the robustness of our results through an extensive numerical analysis of the key parameters of our model. 相似文献
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Dr. C. William Thorpe Stephen J. Cala Janice Chapman Pamela J. Davis 《Journal of voice》2001,15(1):86-104
Recordings of the rib cage and abdominal motions and acoustic output were obtained from five professional opera singers during performance of an aria recorded with two levels of voice projection. The condition of greater projection resulted in a significant increase in the acoustic power in the frequency band 2-4 kHz, relative to the power in the 0-2 kHz band, and a decrease in the mean expiratory flow, implying a move to more efficient vocalization with the greater projection. Also, the condition of greater projection resulted in a larger rib cage, particularly in the lateral dimension, but only a small decrease in the abdominal lateral dimension, suggesting that the greater abdominal support required for a larger projection is obtained by increased activation of abdominal muscles acting medially. 相似文献
216.
Methanol extracts of intact specimens of Cadlina luteomarginata, collected in Howe Sound and Barkley Sound, British Columbia, have been shown to contain sesquitepenoids and a degraded terpenoid. Albicanol (2) and its acetate 1 possess the drimane skeleton. Furodysin (4) and microcionin-2 (5) and microcionin-2 (6) are furanosesquiterpenoids of sponge origin. Luteone (8), the degraded terpenoid, represents a new carbon skeleton. 相似文献
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The non-newtonian effect and the normal stress effect in classical fluids near critical points under shear flow are considered with the renormalization group method. 相似文献
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Tanino K Onuki K Asano K Miyashita M Nakamura T Takahashi Y Kuwajima I 《Journal of the American Chemical Society》2003,125(6):1498-1500
Total synthesis of ingenol, a diterpene isolated from the genus Euphorbia, was accomplished on the basis of the novel key reactions. The highly strained ingenane skeleton was constructed through an intramolecular cyclization reaction of an acetylene dicobalt complex followed by a rearrangement reaction of an epoxy alcohol. The C(3),C(4),C(5)-triol moiety was introduced by a stereoselective double dihydroxylation reaction of a diene having C(2)-C(3) and C(4)-C(5) double bonds. 相似文献
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Nicatinamide adenine dinucleotide (NAD) with an attached perfluoropolyether tail acts as an affinity surfactant in the extraction of the enzyme horse liver alcohol dehydrogenase (HLADH) from an aqueous medium into a fluorous solvent. 相似文献