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991.
胡清淮 《武汉化工学院学报》2004,26(2):73-76
信息技术和生产率的发展以及全球经济一体化的发展趋势,使供应链成为全世界管理科学的热点.本文在阐述供应链基本数学模型的基础上,系统论述了用改进的广义上界(GUB)算法求解大型供应链问题的计算方法. 相似文献
992.
余璆 《上海工程技术大学学报》2004,18(2):127-130
介绍了实现指纹签到系统中高级语言Visual Basic对底层二进制数据的读取方法,数据的存放方式。详细讲述了用Visual Basic编程的关键技术和方法。同时给出了指纹签到系统的使用效果和应用前景。 相似文献
993.
When tin oxide is doped with Sb2O3 and CoO, it shows highly nonlinear current (I)-voltage (V) characteristics. Addition of CoO leads to creation of oxygen vacancies and helps in sintering of SnO2. Antimony oxide acts as a donor and increases the conductivity. The results are nearly the same when antimony oxide is replaced
by tantalum oxide. The observed nonlinear coefficient, α = 30 and the breakdown voltage is 120 V/mm. 相似文献
994.
The graph partitioning problem consists of dividing the vertices of a graph into clusters, such that the weight of the edges crossing between clusters is minimized. We present a new compact mathematical formulation of this problem, based on the use of binary representation for the index of clusters assigned to vertices. This new formulation is almost minimal in terms of the number of variables and constraints and of the density of the constraint matrix. Its linear relaxation brings a very fast computational resolution, compared with the standard one.Experiments were conducted on classical large benchmark graphs designed for comparing heuristic methods. On one hand, these experiments show that the new formulation is surprisingly less time efficient than expected on general k-partitioning problems. On the other hand, the new formulation applied on bisection problems allows to obtain the optimum solution for about ten instances, where only best upper bounds were previously known. 相似文献
995.
In this paper, theoretical analysis of longitudinal free vibration was carried out for Tb-Dy-Fe series magnetostrictive actuator and transducer. The formulations considered two constitutive laws; in one we employ the standard square nonlinear constitutive equation of magnetostriction and in the other we employ the linear piezomagnetic equation. The results obtained from the nonlinear equation can be reduced to the linear piezomagnetic equation when the amplitude of the excitation magnetic field provided by the coil is very small compared to the bias magnetic field and its frequency does not induce resonance of the system. For the case of a relatively large excitation magnetic field, which usually exists for an actuator, the nonlinear constitutive equation should be adopted in order to provide an accurate prediction for the design and analysis of actuator and transducer. Another important aspect is the resonance of the Tb-Dy-Fe series transducers that was revealed in the analysis using the nonlinear constitutive equation. The resonance not only appears at the natural frequencies of the system, but also arises when the frequency of excitation current in the coil happens to be half of one of the natural frequencies of the system. This conclusion cannot be reached using the linear piezomagnetic formulation. 相似文献
996.
997.
Mehrdad Boroushaki Mohammad B. Ghofrani Caro Lucas Mohammad J. Yazdanpanah Nasser Sadati 《Nuclear Engineering and Design》2004,227(3):285-300
Improved load following capability is one of the main technical performances of advanced PWR (APWR). Controlling the nuclear reactor core during load following operation encounters some difficulties. These difficulties mainly arise from nuclear reactor core limitations in local power peaking, while the core is subject to large and sharp variation of local power density during transients. Axial offset (AO) is the parameter usually used to represent of core power peaking, in form of a practical parameter. This paper, proposes a new intelligent approach to AO control of PWR nuclear reactors core during load following operation. This method uses a neural network model of the core to predict the dynamic behavior of the core and a fuzzy critic based on the operator knowledge and experience for the purpose of decision-making during load following operations. Simulation results show that this method can use optimum control rod groups maneuver with variable overlapping and may improve the reactor load following capability. 相似文献
998.
A. P. Tchangani 《Journal of Intelligent Manufacturing》2004,15(1):17-27
This paper deals with decision making in a real time optimization context under uncertain data by linking Bayesian networks (BN) techniques (for uncertainties modeling) and linear programming (LP, for optimization scheme) into a single framework. It is supposed that some external events sensed in real time are susceptible to give relevant information about data. BN consists in graphical representation of probabilistic relationship between variables of a knowledge system and so permit to take into account uncertainty in an expert system by bringing together the classical artificial intelligence (AI) approach and statistics approach. They will be used to estimate numerical values of parameters subjected to the influence of random events for a linear programming program that perform optimization process in order to select optimal values of decision variables of a certain real time decision-making system. 相似文献
999.
The present study examines the behavior of a classical charged point particle in near-elliptic orbits about an infinitely massive and oppositely charged nucleus, while acted upon by applied electromagnetic radiation. As recently shown for near-circular orbits, and now extended here to the elliptical case, rather surprising nonlinear dynamical effects are readily produced for this simple system. A broad range of stability-like conditions can be achieved by applying radiation to this classical atom. A perfect balance condition is examined, which requires an infinite number of plane waves representing harmonics of the orbital motion. By applying a scale factor to this radiation, stability-like conditions are produced where periodic variations in semimajor and semiminor axes occur for extended periods of time, before orbital decay eventually takes over due to the effects of radiation reaction. This work is expected to lead to both practical suggestions on experimental ideas involving controlling ionization and stabilization conditions, as well as hopefully aiding in theoretical explorations of stochastic electrodynamics. 相似文献
1000.
Anthony Savidis 《Software》2004,34(10):977-1009
Smart pointers denote a well‐known technique for collective resource ownership, e.g. sharing dynamic object instances, while usually supporting automatic garbage collection based on reference counting. The original method has been retargeted to serve as a generic defensive programming method for ‘exhaustive tracking’ of erroneous pointer use in C++. Automatic bug tracking is supported in a unified manner both for pointers to heap memory, i.e. free storage, as well as for pointers to stack or global memory, i.e. auto or static storage. Overall, the presented technique (a) offers a simple contract for memory allocation and use; (b) supports type and indirection depth genericity; (c) implements most operators supported for built‐in pointers with embedded bug defense; (d) offers an alternative way of employing a garbage collection facility for memory leak detection; and (e) provides an appropriate collection of utility macros, through which defensive pointers should be used, with an alternative version re‐targeted to normal native pointers. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献