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A ferroelectric liquid-crystal spatial light modulator with an active silicon backplane is used to implement reconfigurable reflective phase holograms. Optical results are presented for an optimized computer-generated Fourier hologram.

Wireless sensor networks (WSNs) can span large geographical regions and collaboratively monitor environmental phenomena, for example, forest fires. By designing a WSN to detect changes to such phenomena, current environmental monitoring systems could be supplemented, if not replaced. This research focuses on incremental insertion events, arising from the elevation of a single node's sensor reading between two consecutive states of network operation. Homology, a field of topology, is used to detect and differentiate between incremental insertion events of interest. Particular homology tools are translated to a distributed environment for 2-dimensional WSN deployments. The result is a novel distributed algorithm that can compute an incremental insertion event associated with a region comprising n nodes in O(n) time, using O(n) storage, and O(n) data passed via messages. A small-scale, laboratory testbed is developed to evaluate the algorithm. Deployment results indicate that only nodes in physical proximity to an event are tasked, thereby conserving network resources and allowing multiple disparate events to be simultaneously monitored. Further, transmission cost is shown to vary linearly with the size of the evolving region, confirming one component of the formal analysis. [ABSTRACT FROM AUTHOR]

The present paper examines whether the formal topological characterisation of spatial relations between moving geographic regions provides an adequate basis for the human conceptualisation of motion events for those regions. The paper focuses on gradual changes in topological relationships caused by continuous transformations of the regions (specifically, translations). Using a series of experiments, the conceptualisation and perception of conceptual neighborhoods is investigated. In particular, the role of conceptual neighborhoods in characterising motion events is scrutinised. The experiments employ a grouping paradigm and a custom-made tool for presenting animated icons. The analysis examines whether paths through a conceptual neighborhood graph sufficiently characterise the conceptualisation of the movement of two regions. The results of the experiments show that changes in topological relations - as detailed by paths through a conceptual neighborhood graph - are not sufficient to characterise the cognitive conceptualisation of moving regions. The similarity ratings show clear effects of perceptually and conceptually induced groupings such as identity (which region is moving), reference (whether a larger or a smaller region is moving), and dynamics (whether both regions are moving at the same time). [ABSTRACT FROM AUTHOR]

This paper presents a new technique for information fusion. Unlike most previous work on information fusion, this paper explores the use of instance-level (extensional) information within the fusion process. This paper proposes an algorithm that can be used automatically to infer the schema-level structure necessary for information fusion from instance-level information. The approach is illustrated using the example of geospatial land-cover data. The method is then extended to operate under uncertainty, such as in cases where the data are inaccurate or imprecise. The paper describes the implementation of the fusion method within a software prototype. Finally, the paper discusses several key topics for future research, including applications of this work to spatial-data mining and the semantic web. [ABSTRACT FROM AUTHOR]