A Novel Method for Visualization of Clustering Results

Sammon mapping is an approach of nonlinear dimension reduction and can be used for visualization. To avoid numerical complexity of the algorithm of traditional Sammon mapping, Kovacs and Abonyi (2004 Kovacs , A. , Abonyi , J. ( 2004 ). Visualization of fuzzy clustering results by modified Sammon mapping . Proceedings of the 3rd International Symposium of Hungarian Researchers on Computational Intelligence 177 – 188 . [Google Scholar]) proposed a modified Sammon mapping method. However, this improvement can only be applied to fuzzy clustering results. By using the property of Fermat point, we develop a new method in this article that can be applied to any clustering results. Different from other methods of visualization, we transfer information of clustering results into concentric circles around the Fermat points. So our procedure can demonstrate the data structure in a more informative way and the clustering results become easier to understand, especially for nonprofessionals. The effectiveness of the proposed method is studied by application to a real data in this article.     

Clustering the mixed panel dataset using Gower's distance and k-prototypes algorithms

ABSTRACT

Panel datasets have been increasingly used in economics to analyze complex economic phenomena. Panel data is a two-dimensional array that combines cross-sectional and time series data. Through constructing a panel data matrix, the clustering method is applied to panel data analysis. This method solves the heterogeneity question of the dependent variable, which belongs to panel data, before the analysis. Clustering is a widely used statistical tool in determining subsets in a given dataset. In this article, we present that the mixed panel dataset is clustered by agglomerative hierarchical algorithms based on Gower's distance and by k-prototypes. The performance of these algorithms has been studied on panel data with mixed numerical and categorical features. The effectiveness of these algorithms is compared by using cluster accuracy. An experimental analysis is illustrated on a real dataset using Stata and R package software.     

Proactive international strategies of cluster SMEs

In this conceptual paper, proactive international strategies of small- and medium-sized enterprises (SMEs) in the cluster context are discussed. The majority of cluster SMEs assume passive roles as network participants in the process of internationalisation. However, a smaller fraction adopts proactive strategies to foreign expansion acting as leaders of networks. SMEs as network leaders are embedded in the source clusters and dependent on local networks that provide them with complementary resources. We assert that this mutual dependence between a firm's resources and the development of industrial agglomeration should be reflected in the strategic options that SMEs adopt when going international. This paper contributes by synthesising and evaluating a comprehensive range of SME-strategic options and by proposing the proactive competitive strategies of SMEs in the international arena that are both feasible and effective. The feasibility of adopting a specific strategy means the suitability for this group of companies, considering their characteristics. The evaluation of the effectiveness of each strategy was performed according to the objectives of avoiding lock-in and of protecting and developing the core competencies embedded in cluster networks. We address the research gap in evaluating the outcomes of SME international strategies and in synthesising a comprehensive range of cluster SMEs' strategic options.     

基于企业学习策略的集群持续创新机制及实证研究

由于集群网络的复杂性,集群创新机制的研究目前较为缺乏,有限的研究也往往假设集群企业具有同质性.本文提出,集群企业依据其在集群网络中的位置采用不同的学习策略,领导型企业更加侧重于探索式学习,跟随型企业更加侧重于利用式学习,两者的分工和异质性互动构成了集群持续创新的内在机理.本文在个体和企业层次双重学习研究的基础上,结合集群特有的组织条件,提出集群双重学习的机制,据此将集群企业进行分类,并建立集群中企业学习的理论模型,接着选取国内某地化工产业集群的236家企业作为样本,运用结构方程模型对集群中企业进行分类检验和比较研究.研究结果表明,集群中不同类型企业的学习策略存在差异,集群网络的作用是产生这一差异的可能原因;集群中不同类型企业的学习策略具有互补性,有利于企业间互动和集群的持续创新.     

中国人口现代化水平区域分布差异的主成分聚类分析

本文主要根据2000年全国第五次人口普查资料,首先选用了11个人口、国民经济和社会发展指标组成人口现代化指标体系。然后,通过SPSS统计分析软件进行主成分分析,选取三个主成分,分别用以反映各省市区人口现代化发展水平在人口结构与生活质量、生育模式与人口素质等三个方面的差异,最后通过聚类分析,将全国各省市人口现代化水平分为四种类型,并分析了四个类型各自的特征与差别及在空间上的区域差异。     

DENSITY ESTIMATION FOR CLUSTERED DATA

The commonly used survey technique of clustering introduces dependence into sample data. Such data is frequently used in economic analysis, though the dependence induced by the sample structure of the data is often ignored. In this paper, the effect of clustering on the non-parametric, kernel estimate of the density, f(x), is examined. The window width commonly used for density estimation for the case of i.i.d. data is shown to no longer be optimal. A new optimal bandwidth using a higher-order kernel is proposed and is shown to give a smaller integrated mean squared error than two window widths which are widely used for the case of i.i.d. data. Several illustrations from simulation are provided.     

The cluster that never was: germ warfare experiments and health authority reality in Dorset

In 1997 intense media coverage raised public concerns about germ warfare simulation experiments conducted by the Ministry of Defence during the 1960s, which included the release of bacteria over Dorset. Families in East Lulworth, Dorset, have linked this with allegedly high rates of miscarriages, still-births, congenital malformations, learning and other neurodevelopmental disabilities in their village. The response of the Dorset Health Authority (DHA) included the examination of background information from the Ministry of Defence, national data on congenital malformations in Dorset, health information collected by campaigners and a systematic health survey conducted by the DHA among former and current residents of East Lulworth. The investigation did not confirm the presence of a cluster. It is debatable whether the DHA should have proceeded with their survey when none of the other more immediately available results indicated the presence of a cluster.     

建立中国(上海)自由贸易试验区动因及其经济效应分析

上海自贸试验区的建立,不是着眼于一城市、一区域的发展,而是力图通过开放转变政府角色、推动制度创新,突破金融领域的改革难点,从而带来"制度红利",充分运用市场调配资源的高效为我国社会主义建设事业服务。上海要实现建成金融中心、贸易中心的宏伟目标,必须从自贸试验区开始,从根本上摒除要素流动的障碍,协调好与经济腹地,与香港、深圳前海等区域的关系,实现区域经济协同发展。上海自贸试验区的建成,必将进一步推动上海服务业产业集聚,推动上海金融中心、航运中心、贸易中心更上一个能级,辐射长江流域甚至更广阔的地域。     

“闪动簇团”与水反常膨胀

本文介绍了液态水结构的“闪动簇团”理论,运用该理论能很好地解释液态水的反常热膨胀问题.