共查询到18条相似文献,搜索用时 93 毫秒
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以传统自适应遗传算法为基础,提出了一种改进的智能组卷算法,基于该算法,设计并实现了一个《编译原理》课程智能组卷系统.结合实际问题建立了组卷问题的数学模型,并针对该数学模型对遗传算法的编码方式和种群最优保存策略进行了改进.改进后的算法在保证组卷质量的前提下,提高了搜索速度并且有效避免了传统遗传算法中经常出现的早熟现象. 相似文献
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利用二次离子质谱测量HgCdTe晶体杂质时发现:杂质在晶片表面附近有富集现象,实验证明该现象属缺陷吸除效应,分析了杂质富集的机理,并利用缺陷吸除工艺成功地减少了HgCdTe晶体内剩余杂质,低温电学参数、光学透过率测量结果表明:该工艺能提高HeCdTe材料的光、电性能。 相似文献
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为了更好地解决组卷质量和组卷速度之间的矛盾,文章提出了一种基于改进遗传算法的组卷策略.对遗传算法的个体编码、初始种群、杂交运算进行改进。实验结果表明,该算法提高了组卷速度,具有较好的实用性。 相似文献
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由于混沌是貌似随机的非随机运动。它对初始条件的极端敏感性。蔡氏电路出现后,通过非线性电路研究混沌产生涡卷成为可能,而蔡氏混沌电路产生涡卷吸引子方法多种多样,利用非线性多项式产生三涡卷混沌吸引子为例,对蔡氏电路进行数学模型分析,然后进行MATLAB仿真。再此基础上,对蔡氏电路进行Multisim仿真同样可以产生三涡卷混沌吸引子,并通过硬件电路系统实现,该硬件电路能够产生三涡卷吸引子,并且可作为一个信号发生电路应用。 相似文献
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A computational model of single rabbit sinoatrial (SA) node cells has been revised to fit data on regional variation of rabbit SA node cell oscillation properties. The revised model simulates differences in oscillation frequency. Maximum diastolic potential, overshoot potential, and peak upstroke velocity observed in cells from different regions of the node. Dynamic properties of electrically coupled cells, each with different intrinsic oscillation frequency, are studied as a function of coupling conductance. Simulation results demonstrate at least four distinct regimes of behavior as coupling conductance is varied: (a) independent oscillation (Gc<1 pS); (b) complex oscillation (1⩽Gc<220 pS); (c) frequency, but not waveform entrainment (Gc⩾220 pS); and (d) frequency and waveform entrainment (Gc⩾50 nS). The conductance of single cardiac myocyte gap junction channels is about 50 pS. These simulations therefore show that very few gap junction channels between each cell are required for frequency entrainment. Analyses of large-scale SA node network models implemented on the Connection Machine CM-200 supercomputer indicate that frequency entrainment of large networks is also supported by a small number of gap junction channels between neighboring cells 相似文献
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Wacker M Galicki M Putsche P Milde T Schwab K Haueisen J Ligges C Witte H 《IEEE transactions on bio-medical engineering》2011,58(11):3069-3077
Repetitive flicker stimulation (photic driving) offers the possibility to study the properties and coupling characteristics of stimulation-sensitive neuronal oscillators by means of the MEG/EEG analysis. With flicker frequencies in the region of the individual alpha band frequency, the dynamics of the entrainment process of the alpha oscillation, as well as the dynamics of the accompanying gamma oscillations and the coupling between the oscillations, are investigated by means of an appropriate combination of time-variant analysis methods. The Hilbert and the Gabor transformation reveal time-variant properties (frequency entrainment, phase locking, and n:m synchronization) of the entrainment process in the whole frequency range. Additionally, time-variant partial directed coherence is applied to identify ocular saccadic interferences and to study the directed information transfer between the recording sites of the simultaneously derived MEG/EEG data during the entrainment. The MEG data is the focus of this methodological study as the entrainment effects of the alpha oscillation are stronger in MEG than in the EEG. The occipital brain region (visual cortex) was mainly investigated and the dynamics of the alpha entrainment quantified. It can be shown that at the beginning of this entrainment, a transient, strongly phase-locked "40-Hz" gamma oscillation occurs. 相似文献
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以西安地铁2号线南门到钟楼的隧道某区段为研究对象,运用理论计算和采用FDS软件进行火灾模拟仿真,找出了火源热释放率与纵向通风临界风速的关系,从而可以根据火源热释放率快速计算出临界风速,达到快速救援的目的。 相似文献