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91.
In this paper, an Adaptive Hierarchical Ant Colony Optimization (AHACO) has been proposed to resolve the traditional machine
loading problem in Flexible Manufacturing Systems (FMS). Machine loading is one of the most important issues that is interlinked
with the efficiency and utilization of FMS. The machine loading problem is formulated in order to minimize the system unbalance
and maximize the throughput, considering the job sequencing, optional machines and technological constraints. The performance
of proposed AHACO has been tested over a number of benchmark problems taken from the literature. Computational results indicate
that the proposed algorithm is more effective and produces promising results as compared to the existing solution methodologies
in the literature. The evaluation and comparison of system efficiency and system utilization justifies the supremacy of the
algorithm. Further, results obtained from the proposed algorithm have been compared with well known random search algorithm
viz. genetic algorithm, simulated annealing, artificial Immune system, simple ant colony optimization, tabu search etc. In
addition, the algorithm has been tested over a randomly generated problem set of varying complexities; the results validate
the robustness and scalability of the algorithm utilizing the concepts of ‘heuristic gap’ and ANOVA analysis. 相似文献
92.
光子晶体是一种具有光子能带及能隙的新型材料。其特有的性质,使光子晶体具有广阔的应用前景。本文基于固体物理学的基本原理,对光子晶体的理论基础进行了简单介绍,根据其特有结构,对光子晶体的特性做了一定分析,并结合现实需要,综述了光子晶体在光学等方面的应用。 相似文献
93.
光子晶体是一种具有光子能带及能隙的新型材料。其特有的性质,使光子晶体具有广阔的应用前景。本文基于固体物理学的基本原理,对光子晶体的理论基础进行了简单介绍,根据其特有结构,对光子晶体的特性做了一定分析,并结合现实需要,综述了光子晶体在光学等方面的应用。 相似文献
94.
A stability robustness test is developed for internally stable, nominal, linear time‐invariant (LTI) feedback systems subject to structured, linear time‐varying uncertainty. There exists (in the literature) a necessary and sufficient structured small gain condition that determines robust stability in such cases. In this paper, the structured small gain theorem is utilized to formulate a (sufficient) stability robustness condition in a scaled LTI ν‐gap metric framework. The scaled LTI ν‐gap metric stability condition is shown to be computable via linear matrix inequality techniques, similar to the structured small gain condition. Apart from a comparison with a generalized robust stability margin as the final part of the stability test, however, the solution algorithm implemented to test the scaled LTI ν‐gap metric stability robustness condition is shown to be independent of knowledge about the controller transfer function (as opposed to the LMI feasibility problem associated with the scaled small gain condition which is dependent on knowledge about the controller). Thus, given a nominal plant and a structured uncertainty set, the stability robustness condition presented in this paper provides a single constraint on a controller (in terms of a large enough generalized robust stability margin) that (sufficiently) guarantees to stabilize all plants in the uncertainty set. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
95.
曾灵 《自动化与仪器仪表》2008,(5)
主要介绍了带钢热连轧厚度控制中采用能耗曲线的方法,对轧机的负荷分配进行分析和设计,详细论述了能耗曲线的建立过程以及运用于实际生产过程中的轧制力分配和辊缝分配的控制方案,并给出了它们各自具体的控制原理、计算公式以及程序框图。该负荷分配方法用于在线,有较好的使用效果。 相似文献
96.
A. P. Litvinchuk C. Thomsen M. Cardona L. Börjesson M. Käll P. Berastegui L. -G. Johansson 《Journal of Superconductivity》1994,7(1):113-116
We report a reflectivity study of thez-polarized TO-phonons of Pr
x
Y1–x
Ba2Cu4O8 and YBa2–y
Sr
y
Cu4O8 alloys in the temperature range 10–300 K. Anomalies of the frequency and linewidth of the plane-oxygen vibration at300 cm–1 due to the opening of the superconducting gap are found to occur upon crossing the superconducting transition temperatureT
c
. Phonon self-energy effects are strongly dependent onT
c
, providing evidence for a relative shift of the gap with respect to the energy of phonon.On leave from the Institute for Semiconductor Physics, Ukrainian Academy of Sciences, 252650 Kiev-28, Ukraine. 相似文献
97.
J. Stecki 《International Journal of Thermophysics》1994,15(6):1103-1113
The planar interface between two simple liquids interacting with 6-12 LJ potentials was simulated by molecular dynamics at a low temperature. The peculiar physical picture. the new breathing mode, the 2 x 2 matrix of the structure factorsS(k l, and the interfacial dynamic structure factor Slk. ), are reported.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A. 相似文献
98.
F. V. Kusmartsev 《Journal of Superconductivity》1994,7(5):787-791
We propose a theory of superconductivity for a crystal having multiple band structure. The theory is valid for the parameter(k
F)/1 when the splitting between bands(k
F
) is small in comparison with the phonon frequency. The theory may be applicable to the doped fullerenes where it is widely supposed that pairing occurs through high-energy intramolecular phonons. As in semiconductors, the bunch of bands is treated by ascribing the highest spin to electrons. We derive the analytic expression for the critical temperature, which strongly depends on the value of the total spin of the Cooper pair, which may be equal toY=0,1,.... In all cases the order parameter is a vector with components proportional to spherical harmonics and at the same time the superconducting gap has no zeros. The data may be fitted to doped fullerenes, if the superconductivity arises fromd-pairing. 相似文献
99.
Given a sequenceA of lengthM and a regular expressionR of lengthP, an approximate regular expression pattern-matching algorithm computes the score of the optimal alignment betweenA and one of the sequencesB exactly matched byR. An alignment between sequencesA=a1a2 ... aM andB=b1b2... bN is a list of ordered pairs, (i1,j1), (i2j2), ..., (it,jtt) such that ik < ik+1 and jk < jk+1. In this case the alignmentaligns symbols aik and bjk, and leaves blocks of unaligned symbols, orgaps, between them. A scoring schemeS associates costs for each aligned symbol pair and each gap. The alignment's score is the sum of the associated costs, and an optimal alignment is one of minimal score. There are a variety of schemes for scoring alignments. In a concave gap penalty scoring schemeS={, w}, a function (a, b) gives the score of each aligned pair of symbolsa andb, and aconcave function w(k) gives the score of a gap of lengthk. A function w is concave if and only if it has the property that, for allk > 1, w(k + 1) –w(k) w(k) –w(k –1). In this paper we present an O(MP(logM + log2
P)) algorithm for approximate regular expression matching for an arbitrary and any concavew.
This work was supported in part by the National Institute of Health under Grant RO1 LM04960. 相似文献
100.
本文提出了一种基于光谱积分宽度法来测量发光二极管(light emitting diode, LED)结温的新方法,并进行了理论分析和实验研究。本方法主要分为光谱数据采集、定标函数的测定和结温测量三个过程。首先,为了测量成本的降低和精度的提高而采用在正常工作电流下采集LED光谱数据,并通过采用不同温度下的光谱积分宽度与选定的某一基准状态下的值逐差可得到线性度达0.99以上的定标函数,并通过此定标函数可实时测定任意状态下的结温。其次,为了比较本方法测量结温的精确性,分别对单色和白光LED采用本方法和业界主流的正向电压法,通过自行设计的基于积分宽度法结温测量系统和美国Mentor Graphics公司的T3Ster型仪器的测量结果进行比较,两种方法测出的结温最大偏差为2.1℃,在可接受的误差范围内。实验结果表明积分宽度法测结温具有高效便捷且低成本的的特点,具有一定的应用前景。 相似文献