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In location-routing problems, the objective is to locate one or many depots within a set of sites (representing customer locations or cities) and to construct delivery routes from the selected depot or depots to the remaining sites at least system cost. The objective function is the sum of depot operating costs, vehicle acquisition costs and routing costs. This paper considers one such problem in which a weight is assigned to each site and where sites are to be visited by vehicles having a given capacity. The solution must be such that the sum of the weights of sites visited on any given route does not exceed the capacity of the visiting vehicle. The formulation of an integer linear program for this problem involves degree constraints, generalized subtour elimination constraints, and chain barring constraints. An exact algorithm, using initial relaxation of most of the problem constraints, is presented which is capable of solving problems with up to twenty sites within a reasonable number of iterations. 相似文献
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Nor-Mycosporin Glutamin, a new unstable compound isolated from sporulating cultures of , has the structure (I). 相似文献
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在前文工作的基础上,结合MNDO/EHMO分子轨道方法和自然杂化轨道方法,具体计算了CC键和CP键的核自旋偶合常数.计算结果表明,1JCC和1JCP主要由成键原子的轨道杂化作用和键极性这两种结构因素所决定.为从简单价键理论角度解释和计算1JCC和1JCP值提供了简便直观的方法. 相似文献
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J. Gerum Susanne Marie Beckurts O. Lüning A. Heiduschka J. Deininger C. H. Bailey H. Kalning Arpin T. Pecaud E. Vautier Th. Merl A. Reuß W. Brendler H. Langfurth J. Grossfeld A. Fornet W. Herter Marchadier Goujon G. Testeni P. Menaul C. T. Dowell Th. v. Fellenberg J. Abel K. Fricke O. Lüning E. Arbenz A. Juckenack A. Fornet und A. Nestler 《Fresenius' Journal of Analytical Chemistry》1924,65(1-2):84-91
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赵乃良 《高校应用数学学报(A辑)》1996,(1):91-96
Nira Dyn等提出的四点插值法是一种典型的自由曲线离散造型方法,但该方法不能控制插值点的切向。本文利用薄板样很可能 量的极小化原理给出了具有切向控制的四点分插值条件。用户可以方便地交互控制任一插值点的切向,使得四点插值法更为有效和实用。 相似文献