Semi-supervised construction of general visualization hierarchies

We have recently developed a principled approach to interactive non-linear hierarchical visualization [8] based on the Generative Topographic Mapping (GTM). Hierarchical plots are needed when a single visualization plot is not sufficient (e.g. when dealing with large quantities of data). In this paper we extend our system by giving the user a choice of initializing the child plots of the current plot in either interactive, or automatic mode. In the interactive mode the user interactively selects ``regions of interest'' as in [8], whereas in the automatic mode an unsupervised minimum message length (MML)-driven construction of a mixture of GTMs is used. The latter is particularly useful when the plots are covered with dense clusters of highly overlapping data projections, making it difficult to use the interactive mode. Such a situation often arises when visualizing large data sets. We illustrate our approach on a data set of 2300 18-dimensional points and mention extension of our system to accommodate discrete data types.

Competition, competitive advantage, and clusters:the ideas of Michael Porter

Comprehensive coverage of all aspects of Michael Porter's works Contributions from leading authorities across the disciplines Contains response from Porter Harvard professor, Michael Porter has been one of the most influential figures in strategic management research over the last three decades. He infused a rigorous theoretical framework of industrial organization economics with the then still embryonic field of strategic management and elevated it to its current status as an academic discipline. Porter's outstanding career is also characterized by its cross-disciplinary nature. Following his most important work on strategic management, he then made a leap to the policy side and dealt with a completely different set of analytical units. More recently he has made a foray into inner city development, environmental regulations, and health care services. Throughout these explorations Porter has maintained his integrative approach, seeking a road that links management case studies and the general model building of mainstream economics. With expert contributors from a range of disciplines including strategic management, economic development, economic geography, and planning, this book assesses the contribution Michael Porter has made to these respective disciplines. It clarifies the sources of tension and controversy relating to all the major strands of Porter's work, and provides academics, students, and practitioners with a critical guide for the application of Porter's models. The book highlights that while many of the criticisms of Porter's ideas are valid, they are almost an inevitable outcome for a scholar who has sought to build bridges across wide disciplinary valleys. His work has provided others with a set of frameworks to explore in more depth the nature of competition, competitive advantage, and clusters from a range of vantage points.