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后马歇尔时代聚集经济理论之分析
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作者 马丁.佩里 孙振明 《湖北经济学院学报》 2008年第2期28-31,共4页
聚集经济理论主要起源于英国学者阿弗里德.马歇尔(Alfred Marshall)。后马歇尔时代,西方不同的学术流派把聚集经济引申出不同分类,这些分类从不同的角度对聚集经济进行探析。马歇尔理论遗留的很多问题依然亟待解决。
关键词 聚集经济 后马歇尔时代 聚集经济分类
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塔里木盆地柯克亚地区原油差异与成因分析 被引量:6
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作者 王东良 李勇 +5 位作者 敬兵 李建立 国建英 曾昌民 张现军 冯晓军 《石油实验地质》 CAS CSCD 北大核心 2007年第2期192-198,共7页
塔里木盆地柯克亚油气田主要含油气层系为新近系中新统西河甫组(N1x)、古近系卡拉塔尔组(E2k)和白垩系。研究表明,该区原油的物性、族组成、饱和烃色谱、饱和烃甾烷、萜烷、碳同位素和中性含氮化合物等参数在纵向和平面上均呈现出有规... 塔里木盆地柯克亚油气田主要含油气层系为新近系中新统西河甫组(N1x)、古近系卡拉塔尔组(E2k)和白垩系。研究表明,该区原油的物性、族组成、饱和烃色谱、饱和烃甾烷、萜烷、碳同位素和中性含氮化合物等参数在纵向和平面上均呈现出有规律的变化。在纵向上,原油密度、咔唑的丰度由下而上逐渐降低,而原油饱和烃含量、C21-/C22+、C21+22/C28+29、C27重排甾烷/C27规则甾烷、碳同位素和气/油比等参数自下而上有逐渐增大的趋势,这些变化趋势主要归结于自下而上的运移分馏作用;而不同层系或同一层系不同油组平面上的特征差异主要受储层沉积相带和物性的制约,是分类聚集作用的结果。 展开更多
关键词 运移分馏 分类聚集 生标特征 柯克亚原油 塔里木盆地
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基于兴趣信任的多agent合作系统的形成与演化研究
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作者 王江涛 陈志刚 邓晓衡 《小型微型计算机系统》 CSCD 北大核心 2013年第2期224-228,共5页
借鉴人类社会学中流行的人际关系模型,提出一种基于"兴趣信任"的多agent合作模型,利用贝叶斯方法对agent的可信度按兴趣领域进行了分类评估,通过agent间基于兴趣信任的链接更新形成稳定的多agent合作系统.最后的仿真实验显示... 借鉴人类社会学中流行的人际关系模型,提出一种基于"兴趣信任"的多agent合作模型,利用贝叶斯方法对agent的可信度按兴趣领域进行了分类评估,通过agent间基于兴趣信任的链接更新形成稳定的多agent合作系统.最后的仿真实验显示,本文提出的基于兴趣信任的合作系统演化方案不仅能有效提高任务的执行成功率,而且能有效改善网络拓扑结构,使所有的a-gent在不同的兴趣领域内聚集在该领域内服务能力较强的可信agent周围,提高了合作对象的选取效率.经过多轮演化后,本方案能使agent在不同的兴趣领域形成"兴趣分类聚集",减小了网络同化现象,突出了agent的个性. 展开更多
关键词 合作系统演化 兴趣信任 多AGENT 兴趣分类聚集
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A FUZZY CLOPE ALGORITHM AND ITS OPTIMAL PARAMETER CHOICE 被引量:1
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作者 Li Jie Gao Xinbo Jiao Licheng 《Journal of Electronics(China)》 2006年第3期384-388,共5页
Among the available clustering algorithms in data mining, the CLOPE algorithm attracts much more attention with its high speed and good performance. However, the proper choice of some parameters in the CLOPE algorithm... Among the available clustering algorithms in data mining, the CLOPE algorithm attracts much more attention with its high speed and good performance. However, the proper choice of some parameters in the CLOPE algorithm directly affects the validity of the clustering results, which is still an open issue. For this purpose, this paper proposes a fuzzy CLOPE algorithm, and presents a method for the optimal parameter choice by defining a modified partition fuzzy degree as a clustering validity function. The experimental results with real data set illustrate the effectiveness of the proposed fuzzy CLOPE algorithm and optimal parameter choice method based on the modified partition fuzzy degree. 展开更多
关键词 Data mining Cluster analysis Cluster validity Categorical attributes Optimal parameter choice
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Toxicity and Accumulation of Selenite in Four Microalgae 被引量:1
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作者 王大志 程兆第 +1 位作者 李少菁 高亚辉 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2003年第3期280-285,共6页
The toxicity and bioaccumulation of selenite in four microalgae, Spirulina platensis, Dunaliella salina, Dunaliella bardawill and Phaeodactylum tricornutum cultured in the presence of selenite were investigated. Lower... The toxicity and bioaccumulation of selenite in four microalgae, Spirulina platensis, Dunaliella salina, Dunaliella bardawill and Phaeodactylum tricornutum cultured in the presence of selenite were investigated. Lower concentrations of selenite were generally nontoxic and frequently stimulated algal growth, while higher concentrations of selenite inhibited algal growth. Selenite was more toxic to D. salina and D. bardawill than to S. platensis and P. tricornutum . All algae cultured in selenite were able to incorporate Se to different degrees, which depended on algal species. The distributions of selenite among intracellular macromolecular compounds were different among algal species: most of the selenite was associated with proteins in S. platensis, D. salina and D. bardawill , while most of the selenite was associated with lipids in P. tricornutum , which reflected the physiological differences among the algae. These observations suggest that algae are able to accumulate selenite and bind it with intracellular macromolecular compounds when exposed to high concentration of selenite. This may represent a form of storage or detoxification of selenite by the algae. 展开更多
关键词 SELENITE MICROALGAE TOXICITY accumulation intracellular distribution
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电视台活动宣传推广如何应用新媒体技术——以福建电视台少儿频道为例
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作者 黄帆 《新媒体研究》 2016年第21期45-46,共2页
互联网时代里,归类为传统媒体的电视媒体受到新媒体的严重冲击。不但节目收视率和广告份额方面受到影响,而且电视台所举办各类活动的推广效果也大打折扣。但是,传统媒体并不应将新媒体看成一个需要决出胜负的对手,而应该分析自身的优势... 互联网时代里,归类为传统媒体的电视媒体受到新媒体的严重冲击。不但节目收视率和广告份额方面受到影响,而且电视台所举办各类活动的推广效果也大打折扣。但是,传统媒体并不应将新媒体看成一个需要决出胜负的对手,而应该分析自身的优势,创造性地使用新媒体技术、利用新媒体的平台优势,在融合中寻找新的发展模式。 展开更多
关键词 聚集分类 传播原点 人脉圈
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Energy Consumption in Wireless Sensor Networks
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作者 金岩 王玲 +1 位作者 杨孝宗 温东新 《Journal of Donghua University(English Edition)》 EI CAS 2007年第5期646-651,共6页
Wireless sensor networks (WSNs) can be used to collect surrounding data by multi-hop. As sensor networks have the constrained and not rechargeable energy resource, energy efficiency is an important design issue for ... Wireless sensor networks (WSNs) can be used to collect surrounding data by multi-hop. As sensor networks have the constrained and not rechargeable energy resource, energy efficiency is an important design issue for its topology. In this paper, the energy consumption issue under the different topology is studied. We derive the exact mathematical expression of energy consumption for the fiat and clustering scheme, respectively. Then the energy consumptions of different schemes are compared. By the comparison, multi-level clustering scheme is more energy efficient in large scale networks. Simulation results demonstrate that our analysis is correct from the view of prolonging the large-scale network lifetime and achieving more power reductions. 展开更多
关键词 wireless sensor networks WSNs energy consumption FLAT CLUSTERING
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Different Criteria for the Optimal Number of Clusters and Selection of Variables with R
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作者 Alessandro Attanasio Maurizio Maravalle Alessio Scalzini 《Journal of Mathematics and System Science》 2013年第9期469-476,共8页
One of the most important problems of clustering is to define the number of classes. In fact, it is not easy to find an appropriate method to measure whether the cluster configuration is acceptable or not. In this pap... One of the most important problems of clustering is to define the number of classes. In fact, it is not easy to find an appropriate method to measure whether the cluster configuration is acceptable or not. In this paper we propose a possible and non-automatic solution considering different criteria of clustering and comparing their results. In this way robust structures of an analyzed dataset can be often caught (or established) and an optimal cluster configuration, which presents a meaningful association, may be defined. In particular, we also focus on the variables which may be used in cluster analysis. In fact, variables which contain little clustering information can cause misleading and not-robustness results. Therefore, three algorithms are employed in this study: K-means partitioning methods, Partitioning Around Medoids (PAM) and the Heuristic Identification of Noisy Variables (HINoV). The results are compared with robust methods ones. 展开更多
关键词 CLUSTERING K-MEANS PAM number of clusters.
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计及离散出力特征的火电机群固有运行灵活性评价方法 被引量:2
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作者 刘教民 郭通 +2 位作者 徐姗姗 李永刚 高亚静 《电力建设》 北大核心 2019年第6期65-73,共9页
考虑到未来一段时期传统火电机组依旧是主要的灵活性供给源,文章提出一种充分反映现有火电机群固有运行灵活性的定量评价方法。固有运行灵活性为火电机群自身通过爬坡或者改变开机组合来平衡负荷波动的能力,只与技术参数和负荷波动范围... 考虑到未来一段时期传统火电机组依旧是主要的灵活性供给源,文章提出一种充分反映现有火电机群固有运行灵活性的定量评价方法。固有运行灵活性为火电机群自身通过爬坡或者改变开机组合来平衡负荷波动的能力,只与技术参数和负荷波动范围有关,与系统的运行方式无关。首先,在单台机组灵活调节特性的基础上,对多台机组构成的机群进行离散组合分析,获得机群层面的灵活调节参数。其次,由于开机状态的离散性,机群出力区间也是离散的,基于这一离散出力特征提出反映机群不同时间尺度的固有运行灵活性评价指标,并采用机组最小启停时间分类聚集的方法减少模型求解的计算量,形成'聚集-分段-交叉-评估'四阶段的指标求解方法。最后,模型的有效性和正确性通过数值算例进行验证,并对提出的评价方法进行了灵敏度分析。结果表明,火电机群固有运行灵活性与其自身的离散出力特征和承担的负荷区间有密切关系。 展开更多
关键词 固有运行灵活性 量化评价 离散出力特征 机组分类聚集
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Symptom clustering in chronic gastritis based on spectral clustering 被引量:2
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作者 Wenhua Zhu Zhaoxiang Fan +5 位作者 Guoping Liu Jianjun Yan Tao Zhong Wu Zheng Ruiqing Wang Chunying Wang 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2014年第4期504-510,共7页
OBJECTIVE: Apply spectral clustering to analyze the patterns of symptoms in patients with chronic gastritis(CG).METHODS: Based on 919 CG subjects, we applied mutual information feature selection to choose the positive... OBJECTIVE: Apply spectral clustering to analyze the patterns of symptoms in patients with chronic gastritis(CG).METHODS: Based on 919 CG subjects, we applied mutual information feature selection to choose the positively correlated symptoms with each pattern.Then, we used the Shi and Malik spectral clustering algorithm to select the top 20 correlated symptoms.RESULTS: We ascertained the results of six patterns.There were three categories for the pattern of accumulation of damp heat in the spleen-stomach(0.00332). There were six categories for the pattern of dampness obstructing the spleen-stomach(0.02466). There were two categories for the pattern of spleen-stomach Qi deficiency(0.013 89).There were three categories for the pattern of spleen-stomach deficiency cold(0.009 15). There were five categories for the pattern of liver-Qistagnation(0.01910).There were four categories for the pattern of stagnant heat in the liver-stomach(0.00585).CONCLUSION: Most of the spectral clustering results of the symptoms of CG patterns were in accordance with clinical experience and Traditional Chinese Medicine theory. Most categories suggested the nature and/or location of the disease. 展开更多
关键词 Gastritis Cluster analysis Pattern Symptom complex
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A CLUSTERING ALGORITHM FOR MIXED NUMERIC AND CATEGORICAL DATA
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作者 Ohn Mar San Van-Nam Huynh Yoshiteru Nakamori 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2003年第4期562-571,共10页
Most of the earlier work on clustering mainly focused on numeric data whoseinherent geometric properties can be exploited to naturally define distance functions between datapoints. However, data mining applications fr... Most of the earlier work on clustering mainly focused on numeric data whoseinherent geometric properties can be exploited to naturally define distance functions between datapoints. However, data mining applications frequently involve many datasets that also consists ofmixed numeric and categorical attributes. In this paper we present a clustering algorithm which isbased on the k-means algorithm. The algorithm clusters objects with numeric and categoricalattributes in a way similar to k-means. The object similarity measure is derived from both numericand categorical attributes. When applied to numeric data, the algorithm is identical to the k-means.The main result of this paper is to provide a method to update the 'cluster centers' of clusteringobjects described by mixed numeric and categorical attributes in the clustering process to minimizethe clustering cost function. The clustering performance of the algorithm is demonstrated with thetwo well known data sets, namely credit approval and abalone databases. 展开更多
关键词 cluster analysis numeric data categorical data k-means algorithm
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Cluster Partition Function and Invariants of 3-Manifolds
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作者 Mauricio ROMO 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2017年第4期937-962,共26页
The author reviews some recent developments in Chern-Simons theory on a hyperbolic 3-manifold M with complex gauge group G. The author focuses on the case of G = SL(N, C) and M being a knot complement: M = S^3\ K. The... The author reviews some recent developments in Chern-Simons theory on a hyperbolic 3-manifold M with complex gauge group G. The author focuses on the case of G = SL(N, C) and M being a knot complement: M = S^3\ K. The main result presented in this note is the cluster partition function, a computational tool that uses cluster algebra techniques to evaluate the Chern-Simons path integral for G = SL(N, C). He also reviews various applications and open questions regarding the cluster partition function and some of its relation with string theory. 展开更多
关键词 Chern-Simons theory KNOTS Cluster algebras
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