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Search Results: 1 - 10 of 271987 matches for " br>米良 "
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The Performance Analysis of Chaotic Frequency-Hopping Sequences

Mi Liang,<br>
电子与信息学报 , 2005,
Abstract: The performance analysis of chaotic Frequency-Hopping(FH)sequences,which are generated by quantization function and reshaping operation based on chaotic map,is presented in this paper.Theory analysis and performance experimental at results show that this sequence is Bernoulli sequence and its Hamming correlation is shown to be Poisson distributed.It is comparable to other FH sequences on the properties of uniform distribution,Hamming correlation and linear complexity when they have the same number of frequency slots and the same period,but much less requirements of iterative operation.It can be concluded that more FH sequences can be generated by this method and they are suitable for FH code-division multiple-access systems.
Comparison of performance between chaotic sequences and nonlinear sequences based on shift register

Mi Liang,Zhu Zhongliang,<br>,朱中梁
电子与信息学报 , 2003,
Abstract: Both chaotic sequences and nonlinear feed-forward logic (NLFFL) sequences based on linear shift register almost have the same properties: the ease of their generation and various families with a large family size and long sequence period, as well as their broadband noise-like and non-linear nature. Their generation methods, correlation properties, Code Division Multiple Access (CDMA) properties and their resistance against correlation attack are compared in the paper. By simulation, it shows that most of their properties are comparable, but chaotic sequences are less vulnerable to correlation attack and jamming than some NLFFL sequences when their period is less than or equal to 1023, so they have more practical value than these nonlinear sequences based on shift register.
Development on genetic algorithm theory and its applications

BIAN Xia,MI Liangb,<br>边霞,b
计算机应用研究 , 2010,
Abstract: This paper first set out the principle and processes of the genetic algorithms, and then introduced a number of schemes on improving the genetic algorithms such as the genetic operators and control parameters, as well as the application of genetic algorithms in computer science and artificial intelligence, automatic control, combinatorial optimization and so on.Finally,presented some remarks on the further research and directions.
Correlating Leaf Area Index of Ponderosa Pine with Hyperspectral CASI Data

Pu Ruiliang,<br>浦瑞,宫鹏,约翰R.
遥感学报 , 1993,
Abstract: Leaf area index (LAI) measurements collected from a Ponderosa pine stand in Oregon have been correlated with the hyperspectral data acquired using a Compact Airborne Spectro-graphic Imager (CASI). Eight LAI values ranging from 0.87 to 2.72 have been measured using an LAI-2000 Plant Canopy Analyzer at the study site. First-order and second-order spectral derivatives have been taken to the CASI data to suppress the effects of the soil background on the forest spectral reflectances. A piece-wise multiple regression procedure has been used to explore the relationships between the LAIs and the CASI data. This procedure produces multivariate linear equations and their associated goodness-of-fit (GOF) values and standard errors (SE) for LAI estimation.Results show that the spectral derivative technique can increase the correlations between the LAIs and the CASI data and thus lead to improved accuracies of LAI estimation. For instance, the highest GOF obtained for single-channel LAI prediction is 0.681 with a SE of 0.345. These have been considerably improved to 0.904 and 0.189, and 0.898 and 0.195 after taking the first-order and the second-order derivatives, respectively.

Pierre Legendre,<br>Pierre Legendre,喻梅,何芳,湘成
植物生态学报 , 2007,
Abstract: β-多样性刻画了地理区域中不同地点物种组成的变化,是理解生态系统功能、生物多样性保护和生态系统管理的一个重要概念。该文介绍了如何从群落组成,相关环境和空间数据角度去分析β-多样性。β-多样性可以通过计算每个地点的多样性指数,进而对可能解释点之间差异的因子所作的假设进行检验来研究。也可以将涵盖所有点的群落组成数据表看作是一系列环境和空间变量的函数,进行直接分析。这种分析应用统计方法将多样性指数或群落组成数据表的方差进行关于环境和空间变量的分解。该文对方差分解进行阐述。方差分解是利用环境和空间变量来解释β-多样性的一种方法。β-多样性是生态学家用来比较不同地点或同一地点不同生态群落的一种手段。方差分解就是将群落组成数据表的总方差无偏分解成由各个解释变量所决定的子方差。调整的决定系数提供了针对多元回归和典范冗余分析的无偏估计。方差分解后,可以对感兴趣的方差解释部分进行显著性检验,同时绘出基于这部分方差解释的预测图。
食品科学 , 2015,
Abstract: ?建立果蔬(白菜、芹菜、草莓和葡萄)中16种新型酰胺类杀菌剂的液相色谱-串联质谱快速分析方法。样品用乙腈提取和氯化钠盐析分层后,上清液直接用0.1%甲酸溶液稀释10倍后进行液相色谱-串联质谱分析。采用acquitybehc18色谱柱分离,用0.1%甲酸溶液-乙腈作为流动相进行梯度洗脱,电喷雾正离子模式电离,多反应监测模式检测,基质校准外标法定量。各物质峰面积与样品质量浓度在2.5×10-4~0.25mg/l范围内呈良好的线性关系,线性回归系数不低于0.9949。在添加量0.01~5.0mg/kg范围内,4种果蔬加标16种杀菌剂的平均添加回收率在85.7%~103.9%范围内,批内相对标准偏差在2.6%~5.2%之间。16种新型酰胺类杀菌剂的检出限为1.0×10-4~3.0×10-3mg/kg,定量限为3.0×10-4~0.01mg/kg。该方法能满足果蔬中16种新型酰胺类杀菌剂残留量分析的要求。
电力系统自动化 , 2014, DOI: 10.7500/AEPS201301064
Abstract: 提出了一种风电场及机组出力损失计算模型与方法。利用风电机组的历史运行数据建立风速、风向与功率间的专家数据库,基于该数据库建立风电机组出力损失计算模型,将机组故障或弃风期间的实测风速和风向代入该模型,计算得出风电机组以及该风电场的实时功率损失及在某时间段内损失的发电量。通过利用现场数据模拟计算,验证了该计算模型与方法的有效性,可对各种原因造成的机组出力损失做出准确计算。该方法既可提高风电场的运行管理水平,还可为风电场参与电网调峰调频提供准确的数据支持。
New Features of Beijing Construction

MI Weng,<br>
地球信息科学 , 2008,
Abstract: The construction of Beijing is experiencing a surprising speed and Beijing has become one of the largest metropolitans in the world.However,the features of an 800-year old capital still remain.This article analyzes the pattern of East and West Chang'an Street,north and south central axes;local color of subway line selection and design;ancient trees and city memories so as to help the readers understand the harmony and perfection of our cultural inheritance during the process of modernization.
A New Encryption Technique for Color Image Information Based on Melting Encryption

MI Jia,<br>
计算机科学 , 2007,
Abstract: A new encryption technique for color image information is proposed based on melting encryption in light of color science.Linear and nonlinear transformation of quantity are applied to the two color images in the RGB and XYZ color space,and these two color images are individually the origin color image used for transporting or storing and the color image used for encryption or decryption.Then color image information is melted to encryption map,which can't be identified and decryption easily.So the texts and images can be transported secretly and securely.
催化学报 , 2003,
Abstract: ?采用水合肼液相还原法制备了负载型镍催化剂,对其催化蒽醌加氢反应的活性进行了考察,采用电感耦合等离子发射光谱、X射线衍射以及H2化学吸附等手段对催化剂进行了表征,并与用氢气还原法制备的催化剂进行了对比.结果表明,用水合肼还原制备的催化剂的Ni粒子较大,Ni分散度及H2吸附量较低,但其催化蒽醌氢化反应的活性高得多.
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