Akinobu Takeuchi

Asymmetric Agglomerative Hierarchical Clustering Algorithms and Their Evaluations

AbstractThis paper presents asymmetric agglomerative hierarchical clustering algorithms in an extensive view point. First, we develop a new updating formula for these algorithms, proposing a general framework to incorporate many algorithms. Next we propose measures to evaluate the fit of asymmetric clustering results to data. Then we demonstrate numerical examples with real data, using the new updating formula and the indices of fit. Discussing empirical findings, through the demonstrative examples, we show new insights into the asymmetric clustering.

Web-based statistical system by using the DLL

Abstract The requirements for statistical software vary with the users’ goals and environmental experience. Although many developers have attempted to create their software for such various demands, it is virtually difficult to develop and offer such a system with a wide variety of users. The offered system could give a solution to this problem. The basic idea is to separate the interface from statistical engine and to apply the web browser as the interface and Dynamic Link Library (DLL) as statistical library. The application of a web browser has great advantages as an interface, e.g. ability of addition of documents, graphical objects, hyperlinks to other relative sites on the web, and so on. These capabilities make it easy to develop an interface to fit users’ wide needs by using the system. Combining a web-based interface page with an appropriate site by hyperlinks, the users can access the site quickly and analyze data while reading related documents.

Dynamic Link Library and Electronic Book for Statistical Quality Control

In this paper, we produce two projects and their results for statistical quality control on the web. The first system named DLLQC: Dynamic Link Library for Statistical Quality Control, is a statistical software library system with the DLLs. The second system named EBQC: Electronic Books for Quality Control, is an e-book system on the Web. Both systems, which can be used freely through the internet, have many contents with the DLLs of statistical analysis and PDF files of e-books.

Measures and Admissibilities for the Structure of Clustering

The problem of selecting a clustering algorithm from the myriad of algorithms has been discussed in recent years. Many researchers have attacked this problem by using the concept of admissibility (e.g. Fisher and Van Ness, 1971, Yadohisa, et al., 1999). We propose a new criterion called the “structured ratio” for measuring the clustering results. It includes the concept of the well-structured admissibility as a special case, and represents some kind of “goodness-of-fit” of the clustering result. New admissibilities of the clustering algorithm and a new agglomerative hierarchical clustering algorithm are also provided by using the structured ratio. Details of the admissibilities of the eight popular algorithms are discussed.

Measures for the structure of clustering and admissibilities of its algorithm

The problem of selecting a clustering algorithm from the myriad of algorithms has been discussed in recent years. Many researchers have attacked this problem by using the concept of admissibility (e.g. Fisher and Van Ness, 1971, Yadohisa, et al., 1999). We propose a new criterion called the structured ratio for measuring the clustering results. It includes the concept of the well-structured admissibility as a special case, and represents some kind of goodness-of-fit of the clustering result. New admissibilities of the clustering algorithm and a new agglomerative hierarchical clustering algorithm are also provided by using the structured ratio. Details of the admissibilities of the eight popular algorithms are discussed.