Temporal and Spatial Information Diffusion in Real Estate Price Changes and Variances

This article examines patterns of temporal and spatial diffusion of real estate price changes. In addition to means, changes in volatility are tracked in reaction to substantial new information, estimated with GARCH-M methods. The data covers towns in Connecticut and near San Francisco. There is evidence of negative feedback at short lags, contrary to previous research on housing and other assets. There is also evidence of a moving average error process which tends to reverse recent shocks. Significantly positive spatial information diffusion is found from neighboring towns in Connecticut but none in control tests on nonneighboring towns. The results also include evidence of a risk-reward tradeoff in housing price changes in the San Francisco area. Copyright American Real Estate and Urban Economics Association.

Using DNA to generate 3D organic art forms

A novel biological software approach to define and evolve 3D computer art forms is described based on a re-implementation of the FormGrow system produced by Latham and Todd at IBM in the early 1990’s. This original work is extended by using DNA sequences as the input to generate complex organic-like forms. The translation of the DNA data to 3D graphic form is performed by two contrasting processes, one intuitive and one informed by the biochemistry. The former involves the development of novel, but simple, look-up tables to generate a code list of functions such as the twisting, bending, stacking, and scaling and their associated parametric values such as angle and scale. The latter involves an analysis of the biochemical properties of the proteins encoded by genes in DNA, which are used to control the parameters of a fixed FormGrow structure. The resulting 3D data sets are then rendered using conventional techniques to create visually appealing art forms. The system maps DNA data into an alternative multi-dimensional space with strong graphic visual features such as intricate branching structures and complex folding. The potential use in scientific visualisation is illustrated by two examples. Forms representing the sickle cell anaemia mutation demonstrate how a point mutation can have a dramatic effect. An animation illustrating the divergent evolution of two proteins with a common ancestor provides a compelling view of an evolutionary process lost in millions of years of natural history