期刊文献+
共找到275篇文章
< 1 2 14 >
每页显示 20 50 100
信阳市区域旅游一体化构想 被引量:12
1
作者 吴国琴 《信阳师范学院学报(自然科学版)》 CAS 北大核心 2005年第2期189-191,206,共4页
运用空间经济学的“核心 外围”理论,结合信阳市旅游资源的特色和分布规律,提出将信阳市的旅游景点进行有机整合,建立品牌核心区,进行一体化设计和营销,创建鲜明的旅游形象,实现信阳市旅游业的持续。
关键词 区域旅游 聚集 一体化 信阳市
下载PDF
基质结构对土壤冲击特性的影响 被引量:8
2
作者 曹晓斌 杜俊乐 +2 位作者 高竹青 田明明 马御棠 《高电压技术》 EI CAS CSCD 北大核心 2017年第11期3769-3776,共8页
研究基质结构差异对土壤冲击特性的影响,在细化土壤介质冲击理论、完善防雷接地研究方面有着十分重要的意义。因而分析了不同基质结构土壤的导电机理;搭建了土壤冲击实验平台,通过实验方法研究了受不同基质结构影响的土壤冲击特性。实... 研究基质结构差异对土壤冲击特性的影响,在细化土壤介质冲击理论、完善防雷接地研究方面有着十分重要的意义。因而分析了不同基质结构土壤的导电机理;搭建了土壤冲击实验平台,通过实验方法研究了受不同基质结构影响的土壤冲击特性。实验结果表明:对于基质为非团聚性结构的土壤,在相同含水量条件下,土壤的冲击电阻率、临界击穿场强和击穿时延均随着土壤粒径的增大而增大,且3者均受到土壤孔隙率和粒径均匀度的影响;对于基质为团聚性结构的土壤,土壤的冲击特性不符合以上规律,且在相同含水量时,红黏土的导电性要弱于均匀粒径的砂质土;用细砂替代土壤开展土壤冲击特性研究是片面的。 展开更多
关键词 土壤基质结构 团聚性 土粒粒径 土壤冲击电阻率 临界击穿场强 击穿时延
下载PDF
Chinese multi-document personal name disambiguation 被引量:8
3
作者 Wang Houfeng(王厚峰) Mei Zheng 《High Technology Letters》 EI CAS 2005年第3期280-283,共4页
This paper presents a new approach to determining whether an interested personal name across doeuments refers to the same entity. Firstly,three vectors for each text are formed: the personal name Boolean vectors deno... This paper presents a new approach to determining whether an interested personal name across doeuments refers to the same entity. Firstly,three vectors for each text are formed: the personal name Boolean vectors denoting whether a personal name occurs the text the biographical word Boolean vector representing title, occupation and so forth, and the feature vector with real values. Then, by combining a heuristic strategy based on Boolean vectors with an agglomeratie clustering algorithm based on feature vectors, it seeks to resolve multi-document personal name coreference. Experimental results show that this approach achieves a good performance by testing on "Wang Gang" corpus. 展开更多
关键词 personal name disambiguation Chinese multi-document heuristic strategy. agglomerative clustering
下载PDF
Analyzing Population Density Disparity in China with GIS-automated Regionalization: The Hu Line Revisited 被引量:5
4
作者 WANG Fahui LIU Cuiling XU Yaping 《Chinese Geographical Science》 SCIE CSCD 2019年第4期541-552,共12页
The famous ’Hu Line’, proposed by Hu Huanyong in 1935, divided China into two regions(southeast and northwest) of comparable area size but drastically different in population. However, the classic Hu Line was derive... The famous ’Hu Line’, proposed by Hu Huanyong in 1935, divided China into two regions(southeast and northwest) of comparable area size but drastically different in population. However, the classic Hu Line was derived manually in absence of reliable census data and computational technologies of modern days. It has been subject to criticism of lack of scientific rigor and accuracy. This research uses a GIS-automated regionalization method, termed REDCAP(Regionalization with Dynamically Constrained Agglomerative Clustering and Partitioning), to reconstruct the demarcation line based on the 2010 county-level census data in China. The results show that the logarithmic transformation of population density is a better measure of attributive homogeneity in derived regions than density itself, and produces two regions of nearly identical area size and greater contrast in population. Specifically, the revised Hu Line by Hu Huanyong in 1990 had the southeast region with 94.4% of total population and 42.9% of total land, and our delineation line yields a southeast region with 97.4% population and 50.8% land. Therefore, the population density ratio of the two regions is 27.1 by our line, much higher than the ratio of 22.4 by the Hu Line, and thus outperforms the Hu Line in deriving regions of maximum density contrast with comparable area size. Furthermore, more regions are delineated to further advance our understanding of population distribution disparity in China. 展开更多
关键词 HU LINE regional population density DISPARITY GIS-automated REGIONALIZATION REDCAP (Regionalization with Dynamically Constrained agglomerative Clustering and Partitioning) China
下载PDF
Simulation research on monomer agglomeration of nonmetallic inclusions in steel with a diffusion limited aggregation model 被引量:4
5
作者 Hong Li Linxin Ning +3 位作者 Juan Wen Jiongming Zhang Yasushi Sasaki Mitsutaka Hino 《Journal of University of Science and Technology Beijing》 CSCD 2006年第2期117-120,共4页
The monomer agglomeration of nonmetallic inclusions was simulated with a diffusion limited aggregation (DLA) model of the fractal theory. The simulation study with a random two-dimensional diffusion was carried out.... The monomer agglomeration of nonmetallic inclusions was simulated with a diffusion limited aggregation (DLA) model of the fractal theory. The simulation study with a random two-dimensional diffusion was carried out. The results indicate that the DLA model can be used for the simulation of agglomeration behavior of the cluster-type inclusions. The morphology of clusters was observed with SEM and compared with the simulated agglomerates. The modelling procedure of the DLA model is applicable for the agglomeration process. The uncertainty of agglomeration process and the persuasive average agglomerative ratio was analyzed. The factors about the agglomerative ratio with the collision path distance and the size of particles or seed were discussed. The adherence of the nonmetallic inclusions on the dam, the weir and the walls of a tundish, and the absorption of inclusions by stopper or nozzle were also discussed. 展开更多
关键词 fractal theory diffusion limited aggregation (DLA) model monomer agglomeration agglomerative ratio nonmetallic inclusions
下载PDF
A Progressive Approach to Generic Object Detection: A Two-Stage Framework for Image Recognition
6
作者 Muhammad Aamir Ziaur Rahman +3 位作者 Waheed Ahmed Abro Uzair Aslam Bhatti Zaheer Ahmed Dayo Muhammad Ishfaq 《Computers, Materials & Continua》 SCIE EI 2023年第6期6351-6373,共23页
Object detection in images has been identified as a critical area of research in computer vision image processing.Research has developed several novel methods for determining an object’s location and category from an... Object detection in images has been identified as a critical area of research in computer vision image processing.Research has developed several novel methods for determining an object’s location and category from an image.However,there is still room for improvement in terms of detection effi-ciency.This study aims to develop a technique for detecting objects in images.To enhance overall detection performance,we considered object detection a two-fold problem,including localization and classification.The proposed method generates class-independent,high-quality,and precise proposals using an agglomerative clustering technique.We then combine these proposals with the relevant input image to train our network on convolutional features.Next,a network refinement module decreases the quantity of generated proposals to produce fewer high-quality candidate proposals.Finally,revised candidate proposals are sent into the network’s detection process to determine the object type.The algorithm’s performance is evaluated using publicly available the PASCAL Visual Object Classes Challenge 2007(VOC2007),VOC2012,and Microsoft Common Objects in Context(MS-COCO)datasets.Using only 100 proposals per image at intersection over union((IoU)=0.5 and 0.7),the proposed method attains Detection Recall(DR)rates of(93.17%and 79.35%)and(69.4%and 58.35%),and Mean Average Best Overlap(MABO)values of(79.25%and 62.65%),for the VOC2007 and MS-COCO datasets,respectively.Besides,it achieves a Mean Average Precision(mAP)of(84.7%and 81.5%)on both VOC datasets.The experiment findings reveal that our method exceeds previous approaches in terms of overall detection performance,proving its effectiveness. 展开更多
关键词 Deep neural network deep learning features agglomerative clustering LOCALIZATIONS REFINEMENT region of interest(ROI) object detection
下载PDF
改进的蚁群算法与凝聚相结合的关键帧提取 被引量:3
7
作者 张建明 刘海燕 孙淑敏 《计算机工程与应用》 CSCD 2013年第3期222-225,233,共5页
关键帧提取技术,对基于内容的视频检索有着重要的作用。为了从不同类型的视频中有效地提取关键帧,提出了改进的蚁群算法与凝聚相结合的关键帧提取算法。该方法提取视频中每帧的颜色与边缘特征向量,利用改进的蚁群算法自组织地对颜色和... 关键帧提取技术,对基于内容的视频检索有着重要的作用。为了从不同类型的视频中有效地提取关键帧,提出了改进的蚁群算法与凝聚相结合的关键帧提取算法。该方法提取视频中每帧的颜色与边缘特征向量,利用改进的蚁群算法自组织地对颜色和边缘特征向量进行聚类,得到初始聚类。通过凝聚算法对初始聚类进行优化,得到最终聚类。提取每类中距离聚类中心最近的向量,将其对应帧作为关键帧。实验结果表明:使用该算法提取的关键帧不仅可以充分表达出视频的主要内容,而且可以根据视频内容的变化提取出适当数量的关键帧。 展开更多
关键词 视频检索 关键帧 改进的蚁群算法 凝聚算法
下载PDF
IAGNES algorithm for protocol recognition
8
作者 Deng Lijun Tan Tiantian +1 位作者 Han Jingwen Tian Tian 《High Technology Letters》 EI CAS 2018年第4期408-416,共9页
In the process of protected protocol recognition,an improved AGglomerative NESting algorithm( IAGNES) with high adaptability is proposed,which is based on the AGglomerative NESting algorithm( AGNES),for the challengin... In the process of protected protocol recognition,an improved AGglomerative NESting algorithm( IAGNES) with high adaptability is proposed,which is based on the AGglomerative NESting algorithm( AGNES),for the challenging issue of how to obtain single protocol data frames from multiprotocol data frames. It can improve accuracy and efficiency by similarity between bit-stream data frames and clusters,extract clusters in the process of clustering. Every cluster obtained contains similarity evaluation index which is helpful to evaluation. More importantly,IAGNES algorithm can automatically recognize the number of cluster. Experiments on the data set published by Lincoln Laboratory shows that the algorithm can cluster the protocol data frames with high accuracy. 展开更多
关键词 IMPROVED agglomerative NESTING algorithm(IAGNES) PROTOCOL RECOGNITION bit-stream
下载PDF
A weight's agglomerative method for detecting communities in weighted networks based on weight's similarity
9
作者 沈毅 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第4期171-178,共8页
This paper proposes the new definition of the community structure of the weighted networks that groups of nodes in which the edge's weights distribute uniformly but at random between them. It can describe the steady ... This paper proposes the new definition of the community structure of the weighted networks that groups of nodes in which the edge's weights distribute uniformly but at random between them. It can describe the steady connections between nodes or some similarity between nodes' functions effectively. In order to detect the community structure efficiently, a threshold coefficient t~ to evaluate the equivalence of edges' weights and a new weighted modularity based on the weight's similarity are proposed. Then, constructing the weighted matrix and using the agglomerative mechanism, it presents a weight's agglomerative method based on optimizing the modularity to detect communities. For a network with n nodes, the algorithm can detect the community structure in time O(n2 log~). Simulations on networks show that the algorithm has higher accuracy and precision than the existing techniques. Furthermore, with the change of t~ the algorithm discovers a special hierarchical organization which can describe the various steady connections between nodes in groups. 展开更多
关键词 complex networks weight's similarity community structure weight's agglomerative method
下载PDF
An Efficient Agglomerative Clustering Algorithm for Web Navigation Pattern Identification
10
作者 A. Anitha 《Circuits and Systems》 2016年第9期2349-2356,共9页
Web log mining is analysis of web log files with web page sequences. Discovering user access patterns from web access are necessary for building adaptive web servers, to improve e-commerce, to carry out cross-marketin... Web log mining is analysis of web log files with web page sequences. Discovering user access patterns from web access are necessary for building adaptive web servers, to improve e-commerce, to carry out cross-marketing, for web personalization, to predict web access sequence etc. In this paper, a new agglomerative clustering technique is proposed to identify users with similar interest, and to determine the motivation for visiting a website. Using this approach, web usage mining is done through different stages namely data cleaning, preprocessing, pattern discovery and pattern analysis. Results are given to explain how this approach produces tight usage clusters than the existing web usage mining techniques. Rather than traditional distance based clustering, the similarity measure is considered during clustering process in order to reduce computational complexity. This paper also deals with the problem of assessing the quality of user session clusters and cluster validity is measured by using statistical test, which measures the distances of clusters distributions to infer their dissimilarity and distinguish level. Using such statistical measures, it is proved that cluster accuracy is improved to the extent of 0.83, over existing k-means clustering with validity measure 0.26, FCM (Fuzzy C Means) clustering with validity measure 0.56. Rough set based clustering with validity measure 0.54 Generation of dense clusters is essential for finding interesting patterns needed for further mining and analysis. 展开更多
关键词 agglomerative Clustering Similarity Measure Cluster Validity Clickstream Sequence TRANSACTION
下载PDF
探讨复杂系统中的群体结构
11
作者 陈骏 陈忠 刘曾荣 《复杂系统与复杂性科学》 EI CSCD 2005年第2期35-38,共4页
为探讨恰当划分复杂系统群体结构的新方法,提出了改进边介数法。在对网络实例空手道俱乐部的研究中,将该方法与传统社会学聚类方法和GN算法进行了对照比较。其实证结果表明了该方法对于正确分析系统的群体结构的有效性。
关键词 群体 分屡聚类 自聚类 系统树图
下载PDF
Quantum Hierarchical Agglomerative Clustering Based on One Dimension Discrete Quantum Walk with Single-Point Phase Defects 被引量:1
12
作者 Gongde Guo Kai Yu +3 位作者 Hui Wang Song Lin Yongzhen Xu Xiaofeng Chen 《Computers, Materials & Continua》 SCIE EI 2020年第11期1397-1409,共13页
As an important branch of machine learning,clustering analysis is widely used in some fields,e.g.,image pattern recognition,social network analysis,information security,and so on.In this paper,we consider the designin... As an important branch of machine learning,clustering analysis is widely used in some fields,e.g.,image pattern recognition,social network analysis,information security,and so on.In this paper,we consider the designing of clustering algorithm in quantum scenario,and propose a quantum hierarchical agglomerative clustering algorithm,which is based on one dimension discrete quantum walk with single-point phase defects.In the proposed algorithm,two nonclassical characters of this kind of quantum walk,localization and ballistic effects,are exploited.At first,each data point is viewed as a particle and performed this kind of quantum walk with a parameter,which is determined by its neighbors.After that,the particles are measured in a calculation basis.In terms of the measurement result,every attribute value of the corresponding data point is modified appropriately.In this way,each data point interacts with its neighbors and moves toward a certain center point.At last,this process is repeated several times until similar data points cluster together and form distinct classes.Simulation experiments on the synthetic and real world data demonstrate the effectiveness of the presented algorithm.Compared with some classical algorithms,the proposed algorithm achieves better clustering results.Moreover,combining quantum cluster assignment method,the presented algorithm can speed up the calculating velocity. 展开更多
关键词 Quantum machine learning discrete quantum walk hierarchical agglomerative clustering
下载PDF
Safest Route Detection via Danger Index Calculation and K-Means Clustering
13
作者 Isha Puthige Kartikay Bansal +8 位作者 Chahat Bindra Mahekk Kapur Dilbag Singh Vipul Kumar Mishra Apeksha Aggarwal Jinhee Lee Byeong-Gwon Kang Yunyoung Nam Reham R.Mostafa 《Computers, Materials & Continua》 SCIE EI 2021年第11期2761-2777,共17页
The study aims to formulate a solution for identifying the safest route between any two inputted Geographical locations.Using the New York City dataset,which provides us with location tagged crime statistics;we are im... The study aims to formulate a solution for identifying the safest route between any two inputted Geographical locations.Using the New York City dataset,which provides us with location tagged crime statistics;we are implementing different clustering algorithms and analysed the results comparatively to discover the best-suited one.The results unveil the fact that the K-Means algorithm best suits for our needs and delivered the best results.Moreover,a comparative analysis has been performed among various clustering techniques to obtain best results.we compared all the achieved results and using the conclusions we have developed a user-friendly application to provide safe route to users.The successful implementation would hopefully aid us to curb the ever-increasing crime rates;as it aims to provide the user with a beforehand knowledge of the route they are about to take.A warning that the path is marked high on danger index would convey the basic hint for the user to decide which path to prefer.Thus,addressing a social problem which needs to be eradicated from our modern era. 展开更多
关键词 agglomerative CLUSTERING crime rate danger index DBSCAN
下载PDF
Composition,Structure and Regeneration Dynamics of Olea ferruginea Royle Forests from Hindukush Range of Pakistan
14
作者 NASRULLAH Khan FAYAZ Ali +1 位作者 KISHWAR Ali SHAHID Shaukat 《Journal of Mountain Science》 SCIE CSCD 2015年第3期647-658,共12页
Abstract" The abundance of Olea ferruginea in Malakand Division has been significantly reduced across its distribution range due to anthropogenic pressure in the recent past. A number of initiatives were taken for gr... Abstract" The abundance of Olea ferruginea in Malakand Division has been significantly reduced across its distribution range due to anthropogenic pressure in the recent past. A number of initiatives were taken for grafting this species to obtain better seeds for oil production, without the basic information on their ecology and management. To address this knowledge gap, we quantified the composition, structure and regeneration dynamics of Olea ferruginea forests in Malakand Division, Hindukush range of Pakistan. In the present study, five communities dominated by Oleaferruginea were identified using Ward's agglomerative cluster analysis. Total tree density ranged from 153-26o2 plants/ha, and basal area from 19.55 to 2353 m~ ha-1 with Olea having a relative density of 51% to 87% and basal area of 48% to 93%, respectively. The density of juveniles of the dominant and subordinate tree species were generally low which reflect their narrow distribution in the study area. Size-class distributions of O. ferruginea disclosed a bell-shaped pattern, indicating that forests were heavily exploited by local inhabitants in previous periods and recently by armed forces owing to security risks in the study area. The age (mean max. 300±34 years) and annual increment (3.2±1.2 years/cm) indicates that the species is long lived and generally slow growing among the different broad leaved species studied so far. However, the oldest trees can be found by the exploration of large diameter trees in the area. In addition, we found a stable linear relationship between the age and diameter (r2 = o.779), indicating that diameter is a good predictor of age for this broad leaved species. In view of its relatively slow growth, longevity and positive ring-width characteristics O. ferruginea seems to be a suitable choice for dendroecological and dendrochronological studies in lesser Himalayan and Hindukush ranges of Pakistan. The results obtained from this study may help in understanding the composition, structure and regenerati 展开更多
关键词 Oleaferruginea Species composition Ward's agglomerative cluster analysis SEEDLING DENDROECOLOGY
下载PDF
A heuristic clustering algorithm based on high density-connected partitions
15
作者 Yuan Lufeng Yao Erlin Tan Guangming 《High Technology Letters》 EI CAS 2018年第2期149-155,共7页
Clustering data with varying densities and complicated structures is important,while many existing clustering algorithms face difficulties for this problem. The reason is that varying densities and complicated structu... Clustering data with varying densities and complicated structures is important,while many existing clustering algorithms face difficulties for this problem. The reason is that varying densities and complicated structure make single algorithms perform badly for different parts of data. More intensive parts are assumed to have more information probably,an algorithm clustering from high density part is proposed,which begins from a tiny distance to find the highest density-connected partition and form corresponding super cores,then distance is iteratively increased by a global heuristic method to cluster parts with different densities. Mean of silhouette coefficient indicates the cluster performance. Denoising function is implemented to eliminate influence of noise and outliers. Many challenging experiments indicate that the algorithm has good performance on data with widely varying densities and extremely complex structures. It decides the optimal number of clusters automatically.Background knowledge is not needed and parameters tuning is easy. It is robust against noise and outliers. 展开更多
关键词 heuristic clustering density-based spatial clustering of applications with noise( DBSCAN) density-based clustering agglomerative clustering machine learning high density-connected partitions optimal clustering number
下载PDF
Regional Planning and Development Under the Maximization of Urban Agglomerative Economies
16
作者 Zhu Yingming 《Ecological Economy》 2005年第3期69-73,共5页
Starting from the meaning and types of urban agglomerative economies, with the analysis of the characteristicsand causes of urban agglomerative economies, this paper puts forward that the regional planning and develop... Starting from the meaning and types of urban agglomerative economies, with the analysis of the characteristicsand causes of urban agglomerative economies, this paper puts forward that the regional planning and development shouldattach importance to urban agglomerative economies, follow the law of the maximization of regional urban agglomerativeeconomies. It also points out the countermeasures and advices to facilitate the regional planning and development based on theprinciple. 展开更多
关键词 urban agglomerative economies regional planning regional development
下载PDF
Site Fidelity and Residency of Tursiops truncatus off the Aragua Coast,Venezuela-First Records of Long Residency
17
作者 S.Cobarrubia-Russo I.Sawyer +1 位作者 M.Gómez-Alceste A.Molero-Lizarraga 《Journal of Marine Science》 2021年第4期46-58,共13页
This study represents the first comprehensive analysis of the residency patterns of a coastal population of bottlenose dolphin off the coast of Aragua,Venezuela,over a multi-year period.Using photo-identification,the ... This study represents the first comprehensive analysis of the residency patterns of a coastal population of bottlenose dolphin off the coast of Aragua,Venezuela,over a multi-year period.Using photo-identification,the most recent study(2019-2020)identified 56 individuals with the time between encounters from one to 344 days between the first and last sighting.Site Fidelity(SF)and Residence(RES)indices were calculated and Agglomerative Hierarchical Clustering(AHC)modeling was performed,with three patterns of residence obtained:resident(25%),semi-resident(17.86%)and transient(57.14%).These results were contrasted with remodeled data from a previous study(2006-2007),showing similar patterns:resident(24.44%),semi-resident(28.89%)and transient(46.67%).Importantly,two individuals were found to have been resident over the extended period.A breeding female sighted for the first time in 2004 and again in 2020(16 years)and the other from 2005 to 2020(15 years).This region is an important area for marine mammals,known to support a resident reproductive population over many years,as well seabirds,sea turtles,whale sharks and fishermen.We recommend that consideration be given to designating the waters as a Marine Protected Area to safeguard the existing population and provide benefit to the surrounding marine environment. 展开更多
关键词 Bottlenose dolphin PHOTO-IDENTIFICATION Residence patterns agglomerative hierarchical clustering VENEZUELA South Caribbean Marine Protected Area(MPA)selection
下载PDF
Data Driven Customer Segmentation for Vietnamese SMEs in Big Data Era
18
作者 Pham Thi Tam Duong Minh Son +1 位作者 Trinh Le Tan Hoang Ha 《Macro Management & Public Policies》 2021年第2期33-43,共11页
Almost Vietnamese big businesses often use outsourcing services to do marketing researches such as analysing and evaluating consumer intention and behaviour,customers’satisfaction,customers’loyalty,market share,mark... Almost Vietnamese big businesses often use outsourcing services to do marketing researches such as analysing and evaluating consumer intention and behaviour,customers’satisfaction,customers’loyalty,market share,market segmentation and some similar marketing studies.One of the most favourite marketing research business in Vietnam is ACNielsen and Vietnam big businesses usually plan and adjust marketing activities based on ACNielsen’s report.Belong to the limitation of budget,Vietnamese small and medium enterprises(SMEs)often do marketing researches by themselves.Among the marketing researches activities in SMEs,customer segmentation is conducted by tools such as Excel,Facebook analytics or only by simple design thinking approach to help save costs.However,these tools are no longer suitable for the age of data information explosion today.This article uses case analysing of the United Kingdom online retailer through clustering algorithm on R package.The result proves clustering method’s superiority in customer segmentation compared to the traditional method(SPSS,Excel,Facebook analytics,design thinking)which Vietnamese SMEs are using.More important,this article helps Vietnamese SMEs understand and apply clustering algorithm on R in customer segmenting on their given data set efficiently.On that basis,Vietnamese SMEs can plan marketing programs and drive their actions as contextualizing and/or personalizing their message to their customers suitably. 展开更多
关键词 Data driven Customer segmentation Behavioural segmentation CLUSTERING agglomerative
下载PDF
我国东、南沿海地区AM真菌群落生态分布研究 被引量:76
19
作者 张美庆 王幼珊 邢礼军 《菌物系统》 CSCD 北大核心 1998年第3期274-277,共4页
在我国东、南沿海地区AM真菌资源调查的基础上研究了AM真菌的群落生态分布和特征。证明球囊霉属在该地区的出现频度和相对多度都最高,其次是硬囊霉属。该区内南四省AM真菌丰度、密度和物种多样性指数均比北三省高。聚类分析结果和上述... 在我国东、南沿海地区AM真菌资源调查的基础上研究了AM真菌的群落生态分布和特征。证明球囊霉属在该地区的出现频度和相对多度都最高,其次是硬囊霉属。该区内南四省AM真菌丰度、密度和物种多样性指数均比北三省高。聚类分析结果和上述相似,说明我国东、南沿海各省AM真菌的丰度、频度、密度、多度和多样性特征由北向南呈规律性变化。 展开更多
关键词 AM真菌 丰度 频度 密度 群落生态学 聚类分析
下载PDF
复杂网络中的社团结构分析算法研究综述 被引量:86
20
作者 解(亻刍) 汪小帆 《复杂系统与复杂性科学》 EI CSCD 2005年第3期1-12,共12页
许多实际网络中都存在着社团结构。为了寻找大规模复杂网络中的社团结构,人们提出了很多算法。本文综述了近几年来比较有代表性的一些算法。首先介绍了计算机科学中最有名的谱平分法和Kernighan-Lin算法,然后介绍了社会学中具有代表性... 许多实际网络中都存在着社团结构。为了寻找大规模复杂网络中的社团结构,人们提出了很多算法。本文综述了近几年来比较有代表性的一些算法。首先介绍了计算机科学中最有名的谱平分法和Kernighan-Lin算法,然后介绍了社会学中具有代表性的分裂算法和凝聚算法,并着重分析了最新提出来的一种寻找网络中彼此重叠的社团结构的派系过滤算法。最后指出了进一步的研究方向。 展开更多
关键词 复杂网络 社团结构 谱平分法 Kernighan-Lin算法 分裂算法 凝聚算法 派系过滤算法
下载PDF
上一页 1 2 14 下一页 到第
使用帮助 返回顶部