公用技术组合逻辑电路设计方法的初步探讨

通过最简逻辑函数,可以很简单的实现组合逻辑电路。但是利用最简逻辑函数实现的逻辑电路却不一定是最简的逻辑电路。本针对此问题提出公用技术组合逻辑电路设计方法这一新的逻辑电路设计方法来进行探讨。通过实例的分析证明了使用公用技术组合逻辑电路设计方法实现的逻辑电路比使用最简逻辑函数实现的逻辑电路更简单,从而提高了逻辑电路的性价比。     

黑箱系统的一种简便自适应预测控制策略

采用一种输入输出增量式一元线性回归模型作为黑箱系统的预测模型,应用投影算法估计模型参数.该模型将对象输出增量分解为2个分量:一个为非零控制增量作用下的强制分量,另一个为控制增量为零时的自由分量,是一种非齐次时变线性模型.此外,应用广义预测控制理论,提出了一种基于该模型的自适应多步预测控制策略,导出了基于该模型的多步最优预测算式和最优控制律.该控制策略不仅具有广义预测控制的强自适应能力和强鲁棒性,且模型参数少,算法简单,适用于黑箱系统的控制.仿真结果表明该控制策略是有效的.     

Involvement of secondary motor areas in externally-triggered single-finger movements of dominant and non-dominant hands

Abstract Whether the secondary motor areas are involved in simple voluntary movements remains controversial. Differences in the neural substrates of movements with the dominant and the non-dominant hands have not been well documented. In the present study, functional magnetic resonance imaging (fMRI) was used to investigate the hemodynamic response in the primary motor cortex (M1), supple-mentary motor area (SMA) and premotor cortex (PMC) in six healthy right-handed subjects while performing a visually-guided finger-tapping task with their dominant or non-dominant hands. Significant activation was observed in M1, SMA and PMC during this externally triggered simple voluntary movement task. While dominant hand movements only activated contralateral motor areas, non-domi-nant hand movements also activated ipsilateral SMA and PMC. The results provide strong evidence for the involvement of the secondary motor areas in simple voluntarymovements, and also suggest that movements of the dominant hand primarily engage the contralateral secondary motor areas, whereas movements of the non-dominant hand engage bilateral secondary motor areas.     

p—adic域上单代数群的存在性定理

设k为p-adic域,给出了所有定义在k上,具有不同类型k-指标的单线性代数群的统一构造方法,从而给出了定义在k上单代数群的存在性的统一证明,并且给出了所有定义在k上单线性代数群的k-有理点群的统一构造。     

关于热力学函数关系简图记忆规律的再探讨

本文用六个简图归纳了热力学中31个重要的函数关系式,并指明了记忆规律。     

Digital modulation classification using multi-layer perceptron and time-frequency features

Considering that real communication signals corrupted by noise are generally nonstationary, and time-frequency distributions are especially suitable for the analysis of nonstationary signals, time-frequency distributions are introduced for the modulation classification of communication signals. The extracted time-frequency features have good classification information, and they are insensitive to signal to noise ratio (SNR) variation. According to good classification by the correct rate of a neural network classifier, a multilayer perceptron (MLP) classifier with better generalization, as well as, addition of time-frequency features set for classifying six different modulation types has been proposed. Computer simulations show that the MLP classifier outperforms the decision-theoretic classifier at low SNRs, and the classification experiments for real MPSK signals verify engineering significance of the MLP classifier.     

Studies of new EST-SSRs derived from Gossypium barbadense

Existing cotton EST-SSR markers are mostly derived from Gossypium arboreum and Gossypium hir-sutum, but EST-SSR markers from Gossypium barbadense are scarce. One hundred and nineteen EST-SSRs were developed based on 98 unique ESTs from a cDNA library constructed in our laboratory using developing fibers from G. barbadense cv. Pima3-79. Among the SSRs, trinucleotide AAG appeared at a high frequency of 11.76%. 36 accessions (consisting of 13 diploids of the A genome, 11 diploids of the D genome and 12 allotetraploids of the AD genome) were employed to test new EST-SSRs. 76 EST-SSRs were successfully amplified, and 313 polymorphic fragments were yielded, with an average of 4.11 fragments per primer pair. The PIC ranged from 0.17 to 0.95 with an average of 0.53. Based on Jaccard’s genetic similarity coefficient, these 36 accessions were clustered into three groups. 21 EST-SSRs exhibited polymorphisms in BC1 population ((Emian22 × Pima3-79) × Emian22), 24 polymor- phic loci were generated, while 22 of the 24 polymorphic loci were integrated with our interspecific BC1 backbone genetic linkage map, and anchored in 12 chromosomes. This study effectively proved that EST-SSRs from G. barbadense are valuable for genetic diversity analysis and genetic mapping.     

电场对单摆动力学行为的影响

设计了一个存在外电场影响的单摆实验装置,并依此建立了运动学方程,采用线性稳定性的分析方法找出了其运动平衡点,且对平衡点稳定性进行了分析,利用计算机数值计算同时结合多种分析方法,得出了电场影响下单摆运动的一些新的特性。     

参数自寻优的伪微分调节器的设计和应用

控制系统设计常常要加入调节器以满足一定的性能要求.该环节的选择、参数的正确与否对系统性能影响很大.一般PID调节器的控制算法与结构较为简单,在工程上有着广泛应用,但它存在不可忽略的缺点,其参数整定的方法也较为复杂.于是从参数优化的角度结合MATLAB仿真软件,依照改进的性能指标(目标函数)自动选出所设计调节器的优化参数,以查表的形式将它们应用在具有转子参数自适应的非线性微分几何解耦控制系统中.结果表明:这种参数优化设计方式的使用具有良好的控制效果和一定的实用价值.