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41.
Summary We propose hot-potato (or, deflection) packet routing algorithms on the two-dimensional mesh. The algorithms are strongly greedy in the sense that they attempt to send packets in good directions whenever possible. Furthermore, the routing operations are simple and independent of the time that has elapsed. The first algorithm gives the best evacuation time known for delivering all the packets to their destinations. A batch ofk packets with maximal source-to-destination distanced
max is delivered in 2(k-1)+d
max. The second algorithm improves this bound tok+d
max when all packets are destined to the same node. This also implies a new bound for the multitarget case, which is the first to take into account the number of in-edges of a node. The third algorithm is designed for routing permutations with source-to-destination distance at most three, in which case the algorithm terminates in at most seven steps. We also show a lower bound of five steps for this problem.
Ishai Ben-Aroya received the B.A. and M.Sc. in computer science from the Technion (Israel Institute of Technology). He is currently working with Microsoft Israel R&D group. His main interests include Routing Algorithms, Cryptography and Computer Security.
Tamar Eilam received the B.A. degree in Computer Science from the Technion IIL in 1995, and is currently studying towards her M.A. degree.
Assaf Schuster received his B.A., M.A. and Ph.D. degrees in Computer Science from the Hebrew University of Jerusalem (the last one in 1991). He is currently a lecturer at the Technion IIL. His main interests include Networks and Routing Algorithms, Parallel and Distributed Computation, Optical Computation and Communication, Dynamically Reconfiguring Networks, and Greedy Hot Potato Routing.This work was supported in part by the French-Israeli grant for cooperation in Computer Science, and by a grant from the Israeli Ministry of Science. An extended abstract appeared in proc. 2nd European Symposium on Algorithms, September 1994 相似文献
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43.
在冶金生产中,热轧是自动化程度高、各种高新技术应用最为广泛的领域.针对过程控制计算机系统在热轧中的应用情况,联系过程控制系统在宝钢热轧发展过程的实际情况,从系统功能的组成及模型、系统接口的实现等方面,对热轧过程控制系统的开发与应用情况,进行了详细的分析. 相似文献
44.
SHENDe-jiu WANGYu-lin GUWei-chao XING Guang-zhong Key Laboratory ofMetastable Materials Science Technology Yanshan University. Qinhuangdao Hebei P. R. China 《材料热处理学报》2004,25(5)
STEEL is the most widely used material in engineering,but unfortunately,steel exhibits poor wear resistanceand obvious contact corrosion.For decades,researchersprepared coatings on steel to improve its properties;ceramic is one of these coatings.To obtain ceramiccoatings on steel,many researchers use techniques suchas plasma spraying,laser cladding,etc.,but some ofthem are too expensive,some of them have a deep heataffected zone in the substrate,and some of them cannot bond well with the subs… 相似文献
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Polycrystalline Ti3SiC2 suffered from serious hot corrosion attack in the mixture of 75wt.%Na2SO4 + 25wt.%NaCl melts at 850 °C. In order to improve the hot corrosion resistance of this material, pre-oxidation treatment was conducted at 1200 °C in air for 2 h. A duplex oxide scale with an outer layer of TiO2 and an inner layer of a mixture of TiO2 and SiO2 was formed during the pre-oxidation. Because the outer oxide layer of the pre-oxidation treated specimens could inhibit hot corrosion process, they exhibited good hot corrosion resistance in the mixture of 75wt.%Na2SO4 + 25wt.%NaCl melts at 850 °C for 50 h. However, during the hot corrosion the outer layer of TiO2 would degrade gradually. Once the outer layer damaged, the hot corrosion rate increased sharply, the corrosion behavior was similar to Ti3SiC2 corroded under the same conditions. The microstructure and phase compositions of the hot corrosion samples were investigated by SEM/EDS and XRD. 相似文献
47.
Solubility measurements of several oxides in molten NaCl-KCl and NaCl-KCl-Na2SO4-K2SO4 were conducted in three different levels of basicity. The dissolution behavior of the oxides showed almost the same tendency as that shown by the dissolution behavior of the oxides in molten Na2SO4 in literature. In a waste incineration environment, a protective Cr2O3 film easily dissolves in molten chlorides as CrO42− because pO2− of the molten chlorides tends to have a small value due to the effect of water vapor contained in the combustion gas. From the result of the solubility measurement, the addition of molybdenum and/or silicon was expected to improve the corrosion resistance of alloys. Laboratory corrosion tests confirmed this expectation. However, the scale analysis suggested that the effect of molybdenum could not be explained completely by only the mechanism derived from the result of the solubility measurement. 相似文献
48.
介绍高强度、大直径、低松弛预应力钢丝用高碳钢盘条在标准型斯太尔摩控制冷却线的生产实践。内容包括作业线概况、原料准备、工艺制度及实际结果和分析。 相似文献
49.
The effects of annealing and annealing with a superimposed pressure of 940 MPa on the primary crystallization behaviour of α-Al and the resulting micro-hardness have been studied for as-quenched Al87Ni7Gd6 metallic glass. Isothermal annealing experiments were conducted for 30 min at 188 °C, 191 °C, and 205 °C in silicone oil maintained either at atmospheric pressure (i.e. 0.1 MPa) or at 940 MPa. XRD analyses detected the evolution of structure with annealing at 0.1 MPa, while specimens annealed with 940 MPa pressure exhibited sharper diffraction peaks than those annealed at 0.1 MPa. DSC measurements were conducted on the as-received amorphous ribbons as well as ribbons annealed at different temperatures at either 0.1. MPa or with 940 MPa superimposed pressure. Specimens annealed with 940 MPa pressure exhibited higher onset temperatures (i.e. Tx1) and temperatures for the first exothermic peak (i.e. Tp1) for primary crystallization. TEM measurements revealed an increase in the volume fraction of α-Al with increases in annealing temperature, while micro-hardness measurements revealed an increase in hardness with increasing amounts of α-Al. Specimens annealed with 940 MPa pressure exhibited further increases in both the volume fraction of α-Al and resulting micro-hardness. 相似文献
50.
论述了非调质钢的性能特点,分析了V、Nb、Ti、Mn、Cr、Si等常用合金元素对非调质钢组织和力学性能的影响,并对热加工工艺、热处理等因素个性能的影响作了分析和讨论。 相似文献