We describe an extensible performance evaluation testbed for dynamic spatial indexing that is directly geared towards Location-Based Services (LBS). The testbed exercises a spatial index with several query types relevant for LBS: proximity queries (range queries), k-nearest neighbor queries, and sorteddistance queries. Performance metrics are defined to quantify the cost (elapsed time) of locat...

In this chapter, a selective overview of the methods used in this thesis will be provided. This overview does not claim to be comprehensive, since only issues which are directly relevant for the methods employed in the empirical chapters will be discussed. In the following subchapter, the technique of functional magnetic resonance imaging (fMRI) will be presented after a brief description of th...

We describe a networked teleoperation system that allows groups of participants to collaboratively explore live remote environments. Participants collaborate using a spatial dynamic voting (SDV) interface that allows them to vote on a sequence of images via a network such as the Internet. The SDV interface runs on each client computer and communicates with a central server that collects, displa...

A spatial dynamic panel data approach is adopted to study regional growth convergence in the U.S. economy. In the neoclassical growth model, regions and countries are assumed to be independent from each other, which may not be valid in the real world. We introduce technological spillovers into the neoclassical framework, showing that the convergence rate is higher and there is spatial interacti...

Introduction Gyral folding has long fascinated scientists, as the character of gyral folding is related to functional compartmentalization. There is a large variability in the pattern of gyral folding across individuals and in genetic disorders but without means of quantifying these differences, it is difficult to define their functional significance or better understand their genetic/epigeneti...

We use cosmological simulations to explore the large-scale effects of reionization. Since reionization is a process that involves a large dynamic range from galaxies to rare bright quasars we need to be able to cover a significant volume of the universe in our simulation without losing the important small scale effects from galaxies. Here we have taken an approach that uses clumping factors der...

Evidence from a number of sources now suggests that the visuo-spatial sketchpad (VSSP) of working memory may be composed of two subsystems: one for maintaining visual information and the other for spatial information. In this paper we present three experiments that examine this fractionation using a developmental approach. In Experiment 1, 5-, 8-, and 10-year old children were presented with a ...

This paper deals with the correspondence between macro and micro spatial interaction and choice models, in both a static and a dynamic context. After a review of recent literature, special attention is devoted to the interpretation of aggregate spatial interaction models (both the conventional gravity or entropy models and the more general theory of movement devëloped by Alonso) in the framewor...

Previous research in spatial cognition has often relied on simple spatial tasks in static environments in order to draw inferences regarding navigation performance. These tasks are typically divided into categories (e.g., egocentric or allocentric) that reflect different two-systems theories. Unfortunately, this two-systems approach has been insufficient for reliably predicting navigation perfo...