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Miklos Ajtai James Aspnes Moni Naor Yuval Rabani Leonard J Schulman Orli Waarts 《Journal of Algorithms in Cognition, Informatics and Logic》1998,29(2):306-357
On-line machine scheduling has been studied extensively, but the fundamental issue of fairness in scheduling is still mostly open. In this paper we explore the issue in settings where there are long-lived processes which should be repeatedly scheduled for various tasks throughout the lifetime of a system. For any such instance we develop a notion ofdesiredload of a process, which is a function of the tasks it participates in. Theunfairnessof a system is the maximum, taken over all processes, of the difference between the desired load and the actual load.An example of such a setting is thecarpool problemsuggested by Fagin and Williams [IBM Journal of Research and Development27(2) (1983), 133–139]. In this problem, a set ofnpeople form a carpool. On each day a subset of the people arrive and one of them is designated as the driver. A scheduling rule is required so that the driver will be determined in a “fair” way.We investigate this problem under various assumptions on the input distribution. We also show that the carpool problems can capture several other problems of fairness in scheduling. 相似文献
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D.E. Aspnes M. Cardona V. Saile M. Skibowski G. Sprüssel 《Solid State Communications》1979,31(2):99-104
We investigate fine structure in energy derivative reflectance (EDR) spectra near 20–21 eV in GaP, GaAs, and GaSb, and near 18–20 eV in InP, InAs, and InSb. Derived energy values for Xc1 thresholds in GaP and GaSb, and Lc1 and Xc1 thresholds in GaAs, agree well with previous Schottky barrier electroreflectance (ER) results. L-X structure splittings in EDR spectra of InAs and InSb, for which Schottky barrier ER measurements cannot be performed, are 0.29 and 0.44 eV, respectively. Estimates of expected locations of these structures, based on XPS and absorption data and band structure calculations, indicate energy deficits of 0.2 eV for In4d-Lc1 and 0.5 eV for In4d-Xc1 transitions, respectively. 相似文献
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F. Christopher Bi Gary E. Aspnes Angel Guzman-Perez Daniel P. Walker 《Tetrahedron letters》2008,49(11):1832-1835
In this Letter, we report a novel approach to the preparation of 3-anilino-pyrazin-2(1H)-ones and 3-anilino-quinoxalin-2(1H)-ones from the corresponding 3-halo pyrazin-2-amines and 3-haloquinoxalin-2-amines, using a microwave-mediated Smiles rearrangement. 相似文献
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James Aspnes William Hurwood 《Journal of Algorithms in Cognition, Informatics and Logic》1998,26(2):386-411
In thecollect problem(M. Saks, N. Shavit, and H. Woll,in“Proceedings of the 2nd ACM–SIAM Symposium on Discrete Algorithms, 1991),nprocessors in a shared-memory system must each learn the values ofnregisters. We give a randomized algorithm that solves the collect problem inO(n log3 n) total read and write operations with high probability, even if timing is under the control of a content-oblivious adversary (a slight weakening of the usual adaptive adversary). This improves on both the trivial upper bound ofO(n2) steps and the best previously known bound ofO(n3/2 log n) steps, and is close to the lower bound of Ω(n log n) steps. Furthermore, we show how this algorithm can be used to obtain a multiuse cooperative collect protocol that isO(log3 n)-competitive in the latency model of Ajtaiet al.(“Proceedings of the 33rd IEEE Symposium on Foundations of Computer Science,” 1994); andO(n1/2 log3/2 n)-competitive in the throughput model of Aspnes and Waarts (“Proceedings of the 28th ACM Symposium on Theory of Computing,” 1996). In both cases the competitive ratios are within a polylogarithmic factor of optimal. 相似文献
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Weber WH Remillard JT McBride JR Aspnes DE 《Physical review. B, Condensed matter》1992,46(23):15085-15091
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We investigate the relative validity of the Bruggeman effective-medium approximation and several alloy models to describe interfaces in the analysis of spectroscopic ellipsometric data of laminar samples, using data obtained on an AlxGa1−xAs multilayer sample fabricated specifically for this purpose. The investigation highlights the types of errors that result from the use of inappropriate models. Optimum results are obtained with the alloy model where the graded-composition regions are approximated with multilayer stacks. 相似文献
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D. E. Aspnes R. Bhat C. Caneau E. Colas L. T. Florez S. Gregory J. P. Harbison I. Kamiya D. E. Aspnes R. Bhat C. Caneau E. Colas L. T. Florez S. Gregory J. P. Harbison I. Kamiya V. G. Keramidas M. A. Koza M. A. A. Pudensi W. E. Quinn S. A. Schwarz M. C. Tamargo H. Tanaka 《Journal of Crystal Growth》1992,120(1-4):71-77
We provide a perspective on current capabilities for optically monitoring and controlling epitaxial growth, and discuss examples taken from recent work at Bellcore. 相似文献