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111.
A model in which jointly optimal stocks of material and finished products are to be chosen is reexamined. While it costs less to hold material, a certain percentage of the random demand not immediately satisfied by previously finished products is lost. We pay particular attention to the dependence of the optimal stocks on the initial ones, which assumes an interesting form. For example, if the stock of finished products is high but the combined stock is low, die quantity of material ordered depends on the stock of finished products. 相似文献
112.
Z Xu LE Reinstein G Yang S Pai G Gluckman PR Almond 《Canadian Metallurgical Quarterly》1997,24(11):1788-1792
The dose distribution from a 32P source has been measured and calculated in order to evaluate its application in endovascular irradiation. The source dimension was 27 mm in length and 0.3 mm in diameter and was embedded in the end of a Ni-Ti wire. Dose measurements were performed using radiochromic film in several specially designed tissue equivalent phantoms. Loevinger's point dose kernel was used for the calculation. The approximate dose rate at a radial distance of 1.5 mm from the center of the source was found to be 6.75 cGy/s per GBq (0.25 cGy/s per mCi), which allows the delivery of a therapeutic dose in a short time interval with a satisfactory homogeneity without stepping the source. However, the dose rate falls off almost exponentially along the radial distance. Therefore it may not be suitable for treating large diameter vessel from a centrally located source. The effect of a curved 32P wire source on the radial dose distribution was also investigated. The results showed that for a maximum bend of 180 degrees the dose rate was increased by as much as 20% along the inner radial distance but decreased by as much as 20% along the outer radial distance compared to the dose along a straight wire. However, for curvatures normally encountered in a clinical situation, the dose rate was changed less than 5%. 相似文献
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在钢的连铸过程中,结晶器保护渣的性质强烈地影响着铸造的行为、钢的质量、以及连铸工艺的环境.本研究采用高温显微技术来研究保护渣的熔化行为,采用液滴测试方法来测定保护渣的熔化速率.结果表明:自由碳是控制保护渣熔化行为的主要因素.熔化速率随碳的反应能力的增加而增加,随着碳含量的减少而增加. 相似文献
115.
Yubin Yang Hui Lin Jixi Jiang 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2006,36(1):162-172
This paper presents a computer-aided cloud-analysis approach by effectively modeling the integration of heterogeneous satellite-observed data and remote sensing images. First, automatic cloud detection and tracking methods are proposed to identify the georeferenced cloud objects in satellite remote sensing images. Then, a data integration modeling mechanism is designed to collect meaningful properties of those detected clouds by integrating the heterogeneous satellite-observed data and imaging into a unified cloud database. Finally, based on the integrated global data schema, a two-phase data mining method employing the decision tree algorithm is implemented to analyze and forecast the meteorological activities of all the cloud objects. Experimental results have shown that the proposed data integration model can effectively extract and synthesize all the useful information from heterogeneous data sources to generate a unified view of knowledge, on the basis of which the evolvement trends of clouds can be analyzed properly. 相似文献
116.
The objective of this research is to investigate the feasibility of a theoretical development which could lead to advanced manipulator concepts offering fast dynamic and control features. Specifically, the application of “dynamic linearization” to a kinematically redundant planar manipulator is studied. In comparing such a manipulator with a standard non-linear, non-redundant design it is shown that in addition to the expected merits in linearity, dexterity, and computational simplicity, savings in actuator energy consumption can also be realized using a relative simple trajectory optimization scheme. 相似文献
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The cost distributions of both the parallel hybrid-hash join and the parallel join-index join algorithms proposed in the above-named work (ibid., vol.1, p.329-43, Sept. 1989) are presented in more detail. The result shows that almost the entire relation may need to be retrieved from disk, though the join selectivity is low. A table of semi-join selectives and cube sizes is given to show the condition that the join-index method performs better than the hybrid-hash method, i.e., the really low selectivity for the join-index method. An error in one of the cost formulas is corrected, and a more efficient method on the final join in the join-index method is proposed 相似文献
120.