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21.
蒋涛 《计算机应用与软件》2005,22(7):143-144,F003
船闸实现基于C/S的运调系统,不仅是船闸现代化管理的需要,而且能够极大程度地提高船闸的工作效率。本文主要应用关系数据库理论分析了系统的用户需求,运用E—R图设计了该系统的数据库,保证了数据库的冗余度和完整性;应用面向对象的理论用UML建模语言分别建立了系统的用例图、类图、顺序图。 相似文献
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Meta-heuristic algorithms for parameter estimation of semi-parametric linear regression models 总被引:1,自引:0,他引:1
Consider the semi-parametric linear regression model Y=β′X+ε, where ε has an unknown distribution F0. The semi-parametric MLE of β under this set-up is called the generalized semi-parametric MLE(GSMLE). Although the GSML estimation of the linear regression model is statistically appealing, it has never been attempted due to difficulties with obtaining the GSML estimates of β and F until recent work on linear regression for complete data and for right-censored data by Yu and Wong [2003a. Asymptotic properties of the generalized semi-parametric MLE in linear regression. Statistica Sinica 13, 311-326; 2003b. Semi-parametric MLE in simple linear regression analysis with interval-censored data. Commun. Statist.—Simulation Comput. 32, 147-164; 2003c. The semi-parametric MLE in linear regression with right censored data. J. Statist. Comput. Simul. 73, 833-848]. However, after obtaining all candidates, their algorithm simply does an exhaustive search to find the GSML estimators. In this paper, it is shown that Yu and Wong's algorithm leads to the so-called dimension disaster. Based on their idea, a simulated annealing algorithm for finding semi-parametric MLE is proposed along with techniques to reduce computations. Experimental results show that the new algorithm runs much faster for multiple linear regression models while keeping the nice features of Yu and Wong's original one. 相似文献
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电力负荷参数记录与监控系统的开发与应用 总被引:1,自引:0,他引:1
介绍了电力负荷参数记录与监控系统的组成、原理、功能以及软、硬件的开发过程。该系统通过对用电单位的用电状况进行实时监测,为用电部门提供电网运行数据。对如何抑峰填谷、科学用电、提高用电管理水平等方面具有重要意义。系统投入运行后表明:系统运行安全可靠,功能强大,电力数据采集全面、准确,社会效益和经济效益显著。 相似文献
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本文在深入研究8B10B编、解码原理的基础上,利用其DWS特性,用Verilog HDL语言实现编、解码算法的描述,并通了modelsim仿真.在ISE9.1i平台上综合后下载到FPGA上实现具体的硬件电路,同时分析了系统各项性能.在PCI Express总线上,实现了一个性能良好的8810B编解码系统,它具有很好的可移植性以及一定的实用价值. 相似文献
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The frequencies of n-graphs, groups of n letters, for n as large as 6 are compiled and used to launch a statistical attack on a running key cipher. Programs written in C++ make the calculations possible. The results of the attack for various values of n are analyzed. 相似文献
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This study compared the effect of load distribution using two different webbing designs on oxygen consumption and running kinematics of soldiers. It was hypothesised that running with webbing that distributes the load closer to the body (M83 Assault Vest) would expend less energy compared to running with conventional webbing (CON). Seven soldiers randomly completed three treadmill trials; an unloaded VO(2)max test, and two loaded (8 kg) efficiency tests using either the M83 or CON webbing. The VO(2)max test and the loaded efficiency tests had 4-min stages at 5, 8, 10 and 12 km h(-1). Energy expenditure was measured via indirect calorimetry and video analysis was used to determine stride frequency (SF) and stride length (SL) during each trial. Participants using the M83 webbing expended significantly (p<0.05) less energy at all four running velocities compared to the CON trials. The M83 webbing resulted in smaller changes to SL and SF from the unloaded trial when compared to the CON trial. These results indicate that the M83 vest that is designed to distribute the load closer to the body may have an energy efficiency advantage over conventional webbing when soldiers are running. 相似文献
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This paper presents a method for generating gaits for a one-legged articulated hopping robot. A static optimization procedure
produces the initial joint velocities for the flight phase, using the principle of conservation of angular momentum and assuming
(nearly) passive flight. Two novel objective functions for this static optimization enable one to choose different gaits by
simply changing a few parameters. A dynamic optimization procedure yields a solution for the flight trajectory that minimizes
control effort. The stance phase (when the foot is touching the ground) becomes a standard two point boundary value problem,
also solved with a dynamic optimization procedure. During the stance phase, the physical joint limitations, ground reaction
forces, and the trajectory of the zero-moment point all constrain the solution. After these single-phase optimizations, a
complete-cycle optimization procedure, incorporating both flight and stance phases, further reduces the control effort and
balances the motion phases. In simulation, the leg hops on even ground and up stairs, exhibiting energy-efficient and intuitively
satisfying gaits. 相似文献