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Search Results: 1 - 10 of 277076 matches for " 张绍武 "
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关于附加沉降预测方法的探讨

地质与勘探 , 1996,
Abstract: 由于我国各地高层和超高层建筑愈来愈多,深基开挖引起地基土隆起也愈来愈引起重视。根据搜集的多项高层和超高层岩土工程勘察资料,提出再压模量法及形状系数法以计算深基开挖引起的地基土回弹再压缩量。
版权标记技术及其前景展望

图书情报工作 , 2004,
Abstract: ?分析数字水印和数字指纹的特征、攻击分析及其在数字作品版权保护中的作用,并对版权标记技术的发展前景作出展望。
数字信息长期保存的策略取向

图书情报工作 , 2000,
Abstract: ?针对数字信息长期保存所面临的难题,提出数字信息长期保存的策略。
基于Arnold映射的分块双层自适应扩散图像加密算法
徐亚,
中国图象图形学报 , 2015, DOI: 10.11834/jig.20150602
Abstract: 目的针对图像安全保障问题,提出一种基于Arnold映射的分块双层自适应扩散数字图像加密(BDAM)算法,提高图像加密效率及安全性.方法首先利用Logistic映射、Tent映射和Sine映射,进行两两组合构建3种新1维混沌映射,提取初始混沌序列;然后定义一个与明文图像矩阵大小相同的初始加密图像矩阵,对其进行分块,预处理Arnold映射参数,正反向联合映射将明文图像矩阵中随机位置像素值,存入初始加密矩阵随机块中的随机位置,并同时进行块内像素、块间自适应扩散,直至填满初始加密矩阵,完成加密.结果针对多种类型灰度图像,通过仿真实验与性能对比分析表明:BDAM算法在信息熵、密钥空间、相关性、敏感性等方面均优于其他加密算法,置乱效果好,对密钥及明文的敏感性高,可取得较好加密效果.结论结合随机置乱的分块双层非线性自适应扩散BDAM算法可有效抵御多种攻击,安全性较高,适用于各种类型灰度图像加密,具有潜在应用价值.
基于边、节点信息融合网络社团挖掘算法的海洋微生物作用模式
,丁鹏,张庭赫
科学通报 , 2013, DOI: 10.1360/972012-952
Abstract: 随着基因测序技术快速发展,产生了大量海洋微生物数据,使未培养(难培养)海洋微生物研究成为可能.常用的统计学方法和统计分析软件,无法深度挖掘隐含在这些大量数据中的海洋微生物作用模式及种群组成多样性.定义了边重要性测度及节点重要性测度,确定社团核心节点,基于节点-社团置信度,提出整合边、节点信息网络社团挖掘算法(CDIEV),并对春、夏、秋、冬4季节下的海洋微生物作用模式进行了研究.首先采用ESPRIT算法将16SrRNA基因序列聚类成微生物操作分类单元(OTU),基于Spearman相关性及P值分别构建春、夏、秋、冬4季微生物作用网络.CDIEV算法仿真结果及网络拓扑参数分析表明春、夏、秋、冬海洋微生物作用网络具有复杂网络"小世界"和"无尺度"特性;4个季节下的海洋微生物作用模式存在一定的差异;CDIEV算法可有效挖掘网络社团,但挖掘结果受添加阈值影响.
小波变换和SHA-1相结合的图像压缩加密
李园园,
中国图象图形学报 , 2013, DOI: 10.11834/jig.20130403
Abstract: 针对图像分层树集划分编码的安全性问题,提出一种将小波变换和SHA-1(securityhashalgorithm-1)相结合的图像加密算法(DSCE)。首先将图像小波变换后的系数分为低频和高频两部分,然后将低频系数、初始密钥及图像像素和,通过SHA-1置乱加密SPIHT编码高频系数;将部分加密高频系数和初始密钥,通过SHA-1置乱加密Huffman编码低频系数,在压缩过程中实现低频和高频部分相互加密。仿真结果表明,DSCE算法密钥空间大,对密钥和明文敏感,同时有效提高图像存储和传输效率。
1982-1983年埃尔-尼诺现象与其他年埃尔-尼诺现象的比较研究
启文,
华东政法大学学报 , 1986,
Abstract: 利用1949-1983年太平洋海温,分析了1982-1983年埃尔-尼诺过程,并与其他八次过程进行了比较,分析了副热带高压对埃尔-尼诺过程的反映,指出不同类型的埃尔-尼诺影响的差异.
基于部分互信息和贝叶斯打分函数的基因调控网络构建算法
Inferring Gene Regulatory Networks Based on Part Mutual Information and Bayesian Scoring Function

刘飞,,高红艳
- , 2017,
Abstract: 从基因表达数据出发重构基因调控网络,可有效挖掘基因间调控关系,深层次地理解生物调控过程。传统的相关性系数模型、偏相关系数模型仅能发现基因间线性关系,而互信息和条件互信息可用于发现基因间的非线性关系,且能够处理高维低样本基因表达数据。但互信息过高估计基因间的相关性,条件互信息过低估计基因间的相关性,从而导致推断出的基因网络假阳性率和假阴性率较高,且不能推断基因调控方向。因而,基于部分互信息和贝叶斯打分函数,提出一种新的基因调控网络构建算法(命名为PMIBSF)。基于部分互信息,PMIBSF算法首先删除初始基因相关网络中的冗余关联边,然后采用贝叶斯网络互信息测试打分函数学习贝叶斯网络结构,快速构建基因调控网络。在计算机模拟网络和真实生物分子网络上,仿真实验结果表明:PMIBSF性能优于目前较流行的LP、PC-alg、NARROMI和ARACNE算法,可高精度构建基因调控网络。
The inference of gene regulatory networks (GRNs) from expression data can mine the direct regulations among genes and gain deep insights into biological processes at a network level. The most widely used criteria are the Pearson correlation coefficient and partial correlation, but they can only measure linearly direct association and miss nonlinear associations. Mutual information (MI) and conditional Mutual information (CMI) not only can overcome those disadvantages, but also can process the gene expression data which are high dimensional and low samples. MI and CMI are widely used in quantifying both linear and nonlinear associations, but they suffer from the serious problems of overestimation and underestimation. GRNS based on MI and CMI suffer from higher false-positive and false-negative problem and can't identify the directions of regulatory interactions. By using the partial mutual information (PMI) and Bayesian scoring function (BSF), in this work, we present a novel algorithm (namely PMIBSF). Tested on the Synthetic networks as well as real biological molecular networks with different sizes and topologies, the results show that PMIBSF can infer RGNs with higher accuracy. The PMIBSF's performance outperforms other state-of-the-art methods, such as LP, PC-alg, NARROMI and ARACNE
辽河油田钻一小学流行性腮腺炎发病情况调查
建文, , 牛树
中国公共卫生 , 1990,
Abstract: ?我们于1987年12月底至1988年2月对辽河油田钻井第一小学6~14岁小学生进行了流行性腮腺炎发病情况调查.共调查学生2545人,其中男性1303人,女性1202人,流行性腮腺炎发病154人,罹患率6.1%,其中男性发病82人,女性发病72人,男女发病之比为1:09.
Prediction of protein homo-oligomer types with a novel approach of glide zoom window feature extraction
基于多策略滑动伸缩窗特征提取方法预测蛋白质同源寡聚体

李启鹏,,潘泉,陈伟
生物物理学报 , 2009,
Abstract: Protein homo-oligomers play an important role in varous life processes .The concept of multi-strategy glide zoom window was proposed and a novel approach of multi-strategy glide zoom window feature extraction was used for predicting protein homo-oligomers. Based on the concept of multi-strategy glide zoom window, the authors chose two strategy glide zoom windows: whole protein sequence glide zoom window and kin amino acid glide zoom window, and for each strategy glide zoom window, three feature vectors of amino acids distance sum, amino acids mean distance and amino acids distribution, were extracted. A series of feature sets were constructed by combining these feature vectors with amino acids composition to form pseudo amino acid compositions (PseAAC). The support vector machine (SVM) was used as base classifier. The 75.37% total accuracy is arrived in jackknife test in the weighted factor conditions, which is 10.05% and 3.82% higher than that of conventional amino acid composition method and that of BG_Zhang in the same condition. The results show that multi-strategy glide zoom window method of extracting feature vectors from protein sequence is effective and feasible, and the feature vectors of multi-strategy glide zoom window may contain more protein structure information.
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