Kozo Sugiyama

Methods for Visual Understanding of Hierarchical System Structures

Two kinds of new methods are developed to obtain effective representations of hierarchies automatically: theoretical and heuristic methods. The methods determine the positions of vertices in two steps. First the order of the vertices in each level is determined to reduce the number of crossings of edges. Then horizontal positions of the vertices are determined to improve further the readability of drawings. The theoretical methods are useful in recognizing the nature of the problem, and the heuristic methods make it possible to enlarge the size of hierarchies with which we can deal. Performance tests of the heuristic methods and several applications are presented.

Visualization of structural information: automatic drawing of compound digraphs

An automatic method for drawing compound digraphs that contain both inclusion edges and adjacency edges are presented. In the method vertices are drawn as rectangles (areas for texts, images, etc.), inclusion edges by the geometric inclusion among the rectangles, and adjacency edges by arrows connecting them. Readability elements such as drawing conventions and rules are identified, and a heuristic algorithm to generate readable diagrams is developed. Several applications are shown to demonstrate the effectiveness of the algorithm. The utilization of curves to improve the quality of diagrams is investigated. A possible set of command primitives for progressively organizing structures within this graph formalism is discussed. The computational time for the applications shows that the algorithm achieves satisfactory performance. >

Graph Drawing by the Magnetic Spring Model

Abstract A novel and heuristic method for drawing graphs is proposed, introducing a new model called the magnetic spring model , that is an extension of the model by Eades. Graph drawing by force-directed placement has mainly been investigated so far for undirected graphs, and the idea of controlling edge orientations has not been considered. The proposed method can control orientations of links and can nicely draw not only undirected graphs but also other classes of graphs such as trees, directed graphs and mixed graphs in a simple and unified manner. Moreover, since the method is based upon simulations of physical systems, it is conceptually intuitive and therefore quite easy to understand, implement and improve the method. The magnetic spring model and algorithm are presented and many examples of drawings and results from statistical experiments are shown to demonstrate the effectiveness of the proposed method.

A Simple and Unified Method for Drawing Graphs: Magnetic-Spring Algorithm

A simple and unified heuristic method for nicely drawing directed, undirected and mixed graphs is proposed basing upon a new model called magnetic-spring model which is an extension of Eadess spring model. In the new model, the idea of controlling edge orientations by magnetic forces is employed. Since the method is conceptually intuitive, it is quite easy to understand, implement, tune and improve it. Examples of layouts and results of experiments are shown to demonstrate extensive possibilities of the method.

The concept of knowledge in KM: a dimensional model

Purpose – This paper seeks to sharpen the concepts of tacit, implicit and explicit knowledge by linking them to findings from cognitive psychology and memory science and thus finding a possibility for measuring non‐explicit knowledge.Design/methodology/approach – A review of KM and cognitive science literature leads to a dimensional model of knowledge types that links the concepts from KM to more specific concepts from psychology. One central assumption of the model was empirically tested and put into practice in one small‐scale KM project.Findings – The concepts in KM can be linked to concepts from psychology and thus receive theoretical support. The developed model enables psychometric access to a part of non‐explicit knowledge through structural assessment techniques. Furthermore, the model has proven to be of value in a practical application in KM.Research limitations/implications – The experiment and the practical application are too small in scope to provide full support for the model. Further resea...

Enhancing D-ABDUCTOR towards a diagrammatic user interface platform

The D-ABDUCTOR system was originally developed as a diagram-based idea organizer with facilities for visualization and manipulation of a large class of graphs. It has since been enhanced to improve its extensibility, and now function exchangeability, functional independence, and configurability without programming have become important features. The enhanced system and its features are illustrated with several examples of its application.

Force-directed drawing method for intersecting clustered graphs

We present a novel force-directed method for drawing an intersecting clustered graph. This is based upon simulation of a virtual physical system. The graph can express complicated structures such as inclusion and intersection between vertices/clusters as well as adjacency, and it is used in diverse fields such as creativity support, software engineering, and semantic Web. We describe definitions, aesthetics, model, algorithm, performance evaluation, and applications.

Emergent media environment for idea creation support

Abstract An interactive computer system for supporting the emergent stages (or upper streams) in human intellectual activities has been developed. In the system it is intended to integrate facilities for supporting generation, collection, organisation, and presentation of ideas and advising on the divergence and convergence of the ideas. This paper explains the facilities of the system and how to use it, and describes some examples of their use.

POST-ANALYSIS OF KNOWLEDGE-CREATION PROCESSES IN SMALL RESEARCH PROJECTS

This paper proposes a work guide (or framework) for analyzing organizational knowledge creation processes of small research projects, integrating basic concepts (or primitives) from several existing knowledge-creation theories. This guide has been developed during the evaluation of projects. We present results of the process analysis of research projects that have been completed recently. We indicate evidence of the concepts through our own experience and remark on differences among processes of different projects.

Evaluation of a thinking support system from operational points of view

A thinking support system D-ABDUCTOR is evaluated from operational points of view. A novel, well-designed and rigorous method, called LCRM is developed to design tasks for evaluation experiments. An experiment using LCRM was made by five subjects, and 245 tasks were performed in total. Results of the experiment show efficiency of D-ABDUCTOR.