期刊文献+
共找到20篇文章
< 1 >
每页显示 20 50 100
基于资源分布矩阵的二分网聚类方法 被引量:7
1
作者 吴亚晶 狄增如 樊瑛 《北京师范大学学报(自然科学版)》 CAS CSCD 北大核心 2010年第5期643-646,共4页
提出了一种直接基于原始二分网的聚类方法,该方法利用二分网上的资源分配过程得到资源分布矩阵,然后用模糊聚类方法对向量进行聚类,用F统计量判定最优的聚类结果.该方法在探测社团结构明显的人工网时具有较高的准确度.
关键词 二分网 资源分布矩阵 聚类方法
下载PDF
基于二分网中心节点识别的产品评论特征-观点词对提取研究 被引量:4
2
作者 刘臣 吉莉 唐莉 《计算机系统应用》 2018年第11期9-16,共8页
本文以电商平台上的产品评论文本为研究对象,针对产品评论中特征词和观点词的识别问题进行了研究.首先构建特征-观点对二分网络,再给出特征-观点对二分网络中节点重要性排序算法,最后将此算法应用到实际的评论文本数据中以检验算法的有... 本文以电商平台上的产品评论文本为研究对象,针对产品评论中特征词和观点词的识别问题进行了研究.首先构建特征-观点对二分网络,再给出特征-观点对二分网络中节点重要性排序算法,最后将此算法应用到实际的评论文本数据中以检验算法的有效性. 展开更多
关键词 特征-观点词对提取 二分网 中心节点识别 产品评论
下载PDF
二分网上的靴襻渗流 被引量:4
3
作者 万宝惠 张鹏 +2 位作者 张晶 狄增如 樊瑛 《物理学报》 SCIE EI CAS CSCD 北大核心 2012年第16期369-374,共6页
靴襻渗流最早应用于统计物理学中研究磁铁因非磁性杂质导致磁有序的降低并最终消失的现象.随着复杂网络研究的深入,许多学者展开网络上的靴襻渗流研究.在自然界中,许多系统自然呈现出二分结构,二分网络是复杂网络中的一种重要的网络模式... 靴襻渗流最早应用于统计物理学中研究磁铁因非磁性杂质导致磁有序的降低并最终消失的现象.随着复杂网络研究的深入,许多学者展开网络上的靴襻渗流研究.在自然界中,许多系统自然呈现出二分结构,二分网络是复杂网络中的一种重要的网络模式.本文通过建立动力学方程和计算机仿真模拟的方法研究二分网上的靴襻渗流,关注的参数是二分网中两类节点初始的活跃比例和活跃阈值,分别用f_1,f_2和Ω_1,Ω_2表示,得到二分网两类节点终态活跃比例随初始活跃比例的变化会发生相变等结论.同时验证了动力学方程与仿真模拟的一致性. 展开更多
关键词 二分网 靴襻渗流 活跃节点比例
原文传递
图书借阅系统网络模型 被引量:1
4
作者 唐金文 《计算机应用》 CSCD 北大核心 2010年第12期10-12,46,共4页
从网络角度,研究了图书借阅这一复杂系统,在建立图书借阅二分网模型基础上,对网络相关参数进行模拟计算,并对计算结果进行理论分析。得到的结论是:读者数目与书籍数目在适当规模比情况下,随着异类节点连接概率的增加,图书借阅二分网具... 从网络角度,研究了图书借阅这一复杂系统,在建立图书借阅二分网模型基础上,对网络相关参数进行模拟计算,并对计算结果进行理论分析。得到的结论是:读者数目与书籍数目在适当规模比情况下,随着异类节点连接概率的增加,图书借阅二分网具有较高的平均聚集系数,较小的平均最短路径,图书借阅二分网络具备小世界效应特征。 展开更多
关键词 图书借阅系统 复杂 二分网 模拟计算
下载PDF
北京师范大学图书借阅系统的网络分析 被引量:8
5
作者 王进良 张鹏 +1 位作者 狄增如 樊瑛 《情报学报》 CSSCI 北大核心 2009年第1期137-141,共5页
本文通过对2005年北京师范大学图书借阅记录的分析,构建了单顶点网和二分网两种网络,给出了图书借阅数据在这两个网络上的度分布,通过比较得到这两个网络的度分布具有时间演化不变性。然后在单顶点网络上抽取了部分数据进行分析,发... 本文通过对2005年北京师范大学图书借阅记录的分析,构建了单顶点网和二分网两种网络,给出了图书借阅数据在这两个网络上的度分布,通过比较得到这两个网络的度分布具有时间演化不变性。然后在单顶点网络上抽取了部分数据进行分析,发现各子网络的平均路径长度L和网络的平均集聚系数C随网络规模增大总体上有减小的趋势;并且网络具有相对较高的平均集聚系数、较小的“平均最短路径长度”,表现出明显的“小世界效应”。最后在二分网上基于同类节点的相似性提出了基于三元组的集聚系数的定义,给出了该集聚系数在北师大图书借阅网络上的分布. 展开更多
关键词 单顶点 二分网 集聚系数 图书络系统
下载PDF
关于新疆大学图书馆图书借阅系统的网络分析
6
作者 刘蒨瑶 《晋图学刊》 2019年第5期13-18,共6页
对于高校图书馆而言,优化馆藏结构显得尤其重要。本文通过采集2016年新疆大学图书馆部分学院的图书借阅数据,建立了图书借阅加权二分网、读者单顶点网络和书籍单顶点网络,并从复杂网络角度分析了三个网络的统计性质,揭示了图书借阅网络... 对于高校图书馆而言,优化馆藏结构显得尤其重要。本文通过采集2016年新疆大学图书馆部分学院的图书借阅数据,建立了图书借阅加权二分网、读者单顶点网络和书籍单顶点网络,并从复杂网络角度分析了三个网络的统计性质,揭示了图书借阅网络的潜在规律,从而为优化图书馆馆藏结构提供依据。 展开更多
关键词 图书借阅 二分网 无标度性 单顶点
下载PDF
基于改进SimRank的产品特征聚类研究 被引量:2
7
作者 刘臣 段俊 《计算机应用研究》 CSCD 北大核心 2019年第7期1951-1954,共4页
针对在线用户评论中产品特征的提取和聚类问题进行了研究,提出一种改进的SimRank算法。将情感词-特征对放入二分网中,在二分网中使用改进后的SimRank算法计算特征词之间的相似度;再通过谱聚类算法对特征相似度进行聚类,提取网络产品的... 针对在线用户评论中产品特征的提取和聚类问题进行了研究,提出一种改进的SimRank算法。将情感词-特征对放入二分网中,在二分网中使用改进后的SimRank算法计算特征词之间的相似度;再通过谱聚类算法对特征相似度进行聚类,提取网络产品的特征集合。以某电脑评论为例,从中提取情感词-特征对进行研究。实验结果显示,改进后的算法准确率更高。改进后的特征相似度检测方法可以作为检测特征相似度的有效方法,实验采用在线产品的评论语料。实验结果表明,使用改进后的SimRank相似度对特征词进行聚类提取出特征更加准确。 展开更多
关键词 SimRank算法 特征聚类 二分网 特征相似度
下载PDF
基于CRF和HITS算法的特征情感对提取 被引量:4
8
作者 唐莉 刘臣 《计算机技术与发展》 2019年第7期71-75,共5页
作为情感分析的子任务之一,特征级情感分析备受关注。条件随机场(CRF)是情感分析任务的常用方法之一,特别是对于产品特征的提取,但是针对特征词与情感词之间的长依存问题难以解决。针对该问题,提出一种基于CRF和HITS算法的两阶段方法来... 作为情感分析的子任务之一,特征级情感分析备受关注。条件随机场(CRF)是情感分析任务的常用方法之一,特别是对于产品特征的提取,但是针对特征词与情感词之间的长依存问题难以解决。针对该问题,提出一种基于CRF和HITS算法的两阶段方法来提取(产品特征-情感词)对。使用CRF并利用词、词性、依存句法关系三种文本特征来对产品评论中的评价特征和情感词进行提取,并利用已提取的特征和情感词分别作为权威节点和枢纽节点来构建特征情感词二分网。使用一种称为MHITS的扩展HITS算法在二分网上计算并对(产品特征-情感词)对进行排序。实验使用了京东平台上三种不同类型产品的评论数据,并与基准方法进行比较,结果表明该模型在准确率、召回率和F1值上表现更平均。 展开更多
关键词 条件随机场 情感分析 依存句法分析 二分网 扩展HITS算法
下载PDF
Study on preparation of In_2O_3 superfine powder via polymer-network process 被引量:1
9
作者 刘胜峰 赵国丹 +1 位作者 韩效钊 唐述培 《Journal of Southeast University(English Edition)》 EI CAS 2004年第2期212-215,共4页
Nanocrystalline,single-phase undoped In 2O 3 was prepared by a polymer-network synthesis technique with indium nitrate as the starting material;several methods such as X-ray diffractometry (XRD) and transmission ele... Nanocrystalline,single-phase undoped In 2O 3 was prepared by a polymer-network synthesis technique with indium nitrate as the starting material;several methods such as X-ray diffractometry (XRD) and transmission electron microscopy (TEM) were employed to obtain detailed information on the crystallography and microstructual appearance of In 2O 3 superfine powders. The influence of the concentration of starting solution,calcination temperature and time on the particle size was also that investigated by means of the XRD patterns. Results indicate that the obtained powders are mostly crystalline single phase with uniform size and also that the size of the products can be controlled under proper condition. 展开更多
关键词 indium trioxide nanoscale particle polymer-network method
下载PDF
Research on Thermodynamic Properties of Polybrominated Diphenylamine by Neural Network 被引量:19
10
作者 堵锡华 庄文昌 +1 位作者 史小琴 冯长君 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2015年第1期59-64,I0001,I0002,共8页
Based on the location of bromine substituents and conjugation matrix, a new substituent po- sition index ~X not only was defined, but also molecular shape indexes Km and electronega- tivity distance vectors Mm of diph... Based on the location of bromine substituents and conjugation matrix, a new substituent po- sition index ~X not only was defined, but also molecular shape indexes Km and electronega- tivity distance vectors Mm of diphenylamine and 209 kinds of polybrominated diphenylamine (PBDPA) molecules were calculated. Then the quantitative structure-property relationships (QSPR) among the thermodynamic properties of 210 organic pollutants and 0X, K3, M29, M36 were founded by Leaps-and-Bounds regression. Using the four structural parameters as input neurons of the artificial neural network, three satisfactory QSPR models with network structures of 4:21:1, 4:24:1, and 4:24:1 respectively, were achieved by the back-propagation algorithm. The total correlation coefficients R were 0.9999, 0.9997, and 0.9995 respectively and the standard errors S were 1.036, 1.469, and 1.510 respectively. The relative mean deviation between the predicted value and the experimental value of Sθ, AfHe and △fGθ- were 0.11%, 0.34% and 0.24% respectively, which indicated that the QSPR models had good stability and superior predictive ability. The results showed that there were good nonlinear correlations between the thermodynamic properties of PBDPAs and the four structural pa- rameters. Thus, it was concluded that the ANN models established by the new substituent position index were fully applicable to predict properties of PBDPAs. 展开更多
关键词 Polybrominated diphenylamine Neural networks Molecular shape index Elec-tronegativity distance vector Substituent position index Thermodynamic properties
下载PDF
Integrated Low-Power CMOS VCO and Its Divide-by-2 Dividers 被引量:1
11
作者 池保勇 石秉学 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第12期1262-1266,共5页
An integrated low power CMOS VCO and its divide by 2 dividers for WLAN transceivers are presented.The VCO is based on on chip symmetrical spiral inductor and differential diode and the divide by 2 dividers are b... An integrated low power CMOS VCO and its divide by 2 dividers for WLAN transceivers are presented.The VCO is based on on chip symmetrical spiral inductor and differential diode and the divide by 2 dividers are based on the ILFD technique.Due to differential LC tanks and ILFD techniques,power consumption is low.The circuit is implemented in a 0 18μm CMOS process.Measurements show the proposed circuit could produce 3 6/1 8GHz dual band LO signals with a wide tuning range and low phase noise.1 8GHz LO signals are quadrature.It consumes 5mA at V DD =1 5V.The size of die area is only 1 0mm×1 0mm. 展开更多
关键词 VCO WLAN transceivers divide by 2 divider
下载PDF
基于在线用户偏好的声誉度量研究
12
作者 吴莹莹 《电子商务》 2018年第4期37-40,共4页
在线用户声誉是描述用户评估能力的重要指标之一,大量已有研究用单一值表示用户声誉,没有考虑用户偏好和兴趣,因此提出一种基于在线用户偏好的声誉度量方法。将用户声誉以向量的形式表示,可以根据向量中的元素得到用户对不同类型产品的... 在线用户声誉是描述用户评估能力的重要指标之一,大量已有研究用单一值表示用户声誉,没有考虑用户偏好和兴趣,因此提出一种基于在线用户偏好的声誉度量方法。将用户声誉以向量的形式表示,可以根据向量中的元素得到用户对不同类型产品的评估能力,这对线上声誉系统和个性化推荐非常重要。 展开更多
关键词 声誓 用户偏好 二分网打分系统
下载PDF
An MDL approach to efficiently discover communities in bipartite network 被引量:1
13
作者 徐开阔 曾春秋 +2 位作者 元昌安 李川 唐常杰 《Journal of Central South University》 SCIE EI CAS 2014年第4期1353-1367,共15页
An minimum description length(MDL) criterion is proposed to choose a good partition for a bipartite network. A heuristic algorithm based on combination theory is presented to approach the optimal partition. As the heu... An minimum description length(MDL) criterion is proposed to choose a good partition for a bipartite network. A heuristic algorithm based on combination theory is presented to approach the optimal partition. As the heuristic algorithm automatically searches for the number of partitions, no user intervention is required. Finally, experiments are conducted on various datasets, and the results show that our method generates higher quality results than the state-of-art methods, cross-association and bipartite, recursively induced modules. Experiment results also show the good scalability of the proposed algorithm. The method is applied to traditional Chinese medicine(TCM) formula and Chinese herbal network whose community structure is not well known, and found that it detects significant and it is informative community division. 展开更多
关键词 community detection bipartite network minimum description length
下载PDF
Automated retinal blood vessels segmentation based on simplified PCNN and fast 2D-Otsu algorithm 被引量:9
14
作者 姚畅 陈后金 《Journal of Central South University》 SCIE EI CAS 2009年第4期640-646,共7页
According to the characteristics of dynamic firing in pulse coupled neural network (PCNN) and regional configuration in retinal blood vessel network, a new method combined with simplified PCNN and fast 2D-Otsu algorit... According to the characteristics of dynamic firing in pulse coupled neural network (PCNN) and regional configuration in retinal blood vessel network, a new method combined with simplified PCNN and fast 2D-Otsu algorithm was proposed for automated retinal blood vessels segmentation. Firstly, 2D Gaussian matched filter was used to enhance the retinal images and simplified PCNN was employed to segment the blood vessels by firing neighborhood neurons. Then, fast 2D-Otsu algorithm was introduced to search the best segmentation results and iteration times with less computation time. Finally, the whole vessel network was obtained via analyzing the regional connectivity. Experiments implemented on the public Hoover database indicate that this new method gets a 0.803 5 true positive rate and a 0.028 0 false positive rate on an average. According to the test results, compared with Hoover algorithm and method of PCNN and 1D-Otsu, the proposed method shows much better performance. 展开更多
关键词 blood vessel segmentation pulse coupled neural network (PCNN) OTSU NEURON
下载PDF
SPEECH EMOTION RECOGNITION USING MODIFIED QUADRATIC DISCRIMINATION FUNCTION 被引量:9
15
作者 Zhao Yan Zhao Li Zou Cairong Yu Yinhua 《Journal of Electronics(China)》 2008年第6期840-844,共5页
Quadratic Discrimination Function (QDF) is commonly used in speech emotion recognition, which proceeds on the premise that the input data is normal distribution. In this paper, we propose a transformation to normali... Quadratic Discrimination Function (QDF) is commonly used in speech emotion recognition, which proceeds on the premise that the input data is normal distribution. In this paper, we propose a transformation to normalize the emotional features, emotion recognition. Features based on prosody then derivate a Modified QDF (MQDF) to speech and voice quality are extracted and Principal Component Analysis Neural Network (PCANN) is used to reduce dimension of the feature vectors. The results show that voice quality features are effective supplement for recognition, and the method in this paper could improve the recognition ratio effectively. 展开更多
关键词 Speech emotion recognition Principal Component Analysis Neural Network (PCANN) Modified Quadratic Discrimination Function (MQDF)
下载PDF
二元随机网 被引量:3
16
作者 陈宏斌 樊瑛 +1 位作者 方锦清 狄增如 《物理学报》 SCIE EI CAS CSCD 北大核心 2009年第3期1383-1390,共8页
在二分网的基础上明确提出了二元网的概念:同样包含两类节点,二分网同类节点之间没有连接,而二元网同类节点之间可以有连接.构建了一个二元随机网模型,并对二元随机网的结构性质进行研究.二元随机网可以具有小世界效应,并且其平均最短... 在二分网的基础上明确提出了二元网的概念:同样包含两类节点,二分网同类节点之间没有连接,而二元网同类节点之间可以有连接.构建了一个二元随机网模型,并对二元随机网的结构性质进行研究.二元随机网可以具有小世界效应,并且其平均最短路径长度比单元随机网还要小.另外,两类节点的规模比是一个重要参量,会对网络的结构性质产生重大影响. 展开更多
关键词 复杂 二分网 二元 小世界
原文传递
Thermal analysis of laser diode module by an equivalent electrical network method
17
作者 YANG Ming-wei XU Wen-hai TANG Wen-yan 《Optoelectronics Letters》 EI 2006年第4期273-277,共5页
An equivalent electrical network method is presented in this paper to analyze the cooling characteristics of a laser diode module (LDM).And a modified equivalent model of a thermoelectric cooler (TEC) with an adjuncti... An equivalent electrical network method is presented in this paper to analyze the cooling characteristics of a laser diode module (LDM).And a modified equivalent model of a thermoelectric cooler (TEC) with an adjunctive thermal resistance and a contact resistance is proposed.The performance of a commercial TEC has been simulated.The thermal analysis of a LDM incorporated with a TEC has been performed by using an equivalent circuit model of the LDM.In the analysis the change of LD current,TEC current,and the ambient temperature are all considered.It shows that the equivalent circuit approach is an effective tool for the qualitative analysis of TEC and LDM. 展开更多
关键词 激光二极管 热分析 等效电 热电冷却器
下载PDF
An Automated Approach to Passive Sonar Classification Using Binary Image Features
18
作者 Vahid Vahidpour Amlr Rastegarnia Azam Khalili 《Journal of Marine Science and Application》 CSCD 2015年第3期327-333,共7页
This paper proposes a new method for ship recognition and classification using sound produced and radiated underwater. To do so, a three-step procedure is proposed. First, the preprocessing operations are utilized to ... This paper proposes a new method for ship recognition and classification using sound produced and radiated underwater. To do so, a three-step procedure is proposed. First, the preprocessing operations are utilized to reduce noise effects and provide signal for feature extraction. Second, a binary image, made from frequency spectrum of signal segmentation, is formed to extract effective features. Third, a neural classifier is designed to classify the signals. Two approaches, the proposed method and the fractal-based method are compared and tested on real data. The comparative results indicated better recognition ability and more robust performance of the proposed method than the fractal-based method. Therefore, the proposed method could improve the recognition accuracy of underwater acoustic targets. 展开更多
关键词 binary image passive sonar neural classifier ship recognition short-time Fourier transform fractal-based method
下载PDF
NETWORK ANALYSIS OF TERRORIST ACTIVITIES 被引量:2
19
作者 FU Julei FAN Ying +1 位作者 WANG Yang WANG Shouyang 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2014年第6期1079-1094,共16页
This paper uses an extensive network approach to "East Turkistan" activities by building both the one-mode and the bipartite networks for these activities.In the one-mode network,centrality analysis and spec... This paper uses an extensive network approach to "East Turkistan" activities by building both the one-mode and the bipartite networks for these activities.In the one-mode network,centrality analysis and spectrum analysis are used to describe the importance of each vertex.On this basis,two types of core vertices——The center of communities and the intermediary vertices among communities— are distinguished.The weighted extreme optimization(WEO) algorithm is also applied to detect communities in the one-mode network.In the "terrorist-terrorist organization" bipartite network,the authors adopt centrality analysis as well as clustering analysis based on the original bipartite network in order to calculate the importance of each vertex,and apply the edge clustering coefficient algorithm to detect the communities.The comparative and empirical analysis indicates that this research has been proved to be an effective way to identify the core members,key organizations,and communities in the network of "East Turkistan" terrorist activity.The results can provide a scientific basis for the analysis of "East Turkistan" terrorist activity,and thus provide decision support for the real work of "anti-terrorism". 展开更多
关键词 ANTI-TERRORISM complex networks terrorist activity network vertex centrality.
原文传递
TRACKING ERROR REDUCTION IN CNC MACHINING BY RESHAPING THE KINEMATIC TRAJECTORY 被引量:2
20
作者 GUO Jianxin ZHANG Qiang GAO Xiao-Shan 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2013年第5期817-835,共19页
In this paper,a method of reducing the tracking error in CNC machining is proposed.The structured neural network is used to approximate the discontinuous friction in CNC machining,which has jump points and uncertainti... In this paper,a method of reducing the tracking error in CNC machining is proposed.The structured neural network is used to approximate the discontinuous friction in CNC machining,which has jump points and uncertainties.With the estimated nonlinear friction function,the reshaped trajectory can be computed from the desired one by solving a second order ODE such that when the reshaped trajectory is fed into the CNC controller,the output is the desired trajectory and the tracking error is eliminated in certain sense.The proposed reshape method is also shown to be robust with respect to certain parameters of the dynamic system. 展开更多
关键词 CNC controller ROBUSTNESS structured neural network tracking error.
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部