Virtual malls allow consumers to shop and purchase products on the World Wide Web from multiple stores. This paper presents a virtual mall in which stores may be distributed across multiple Web sites. Stores participate in the virtual mall by communicating with a mall coordinator. The virtual mall allows shoppers to perform actions across multiple stores simultaneously such as viewing product a...

This paper attempts to provide an answer to some questions that remain either poorly understood, or not well documented in the literature, on basic issues related to intensity modulated radiation therapy (IMRT). The questions examined are: the relationship between degeneracy and frequency response of optimizations, effects of initial beamlet fluence assignment and stopping point, what does filt...

Numerical results that demonstrate how ion emissive surfaces should be shaped to induce the formation of well-focused, high-current beamlets are presented. Results obtained when the sheath shape and position are established and then held constant as operating conditions are changed are compared to corresponding results obtained with a conventional plasma sheath that moves. These comparisons sho...

Due to their abilities to succinctly capture features at different scales and directions, wavelet-based decomposition or representation methods have found wide use in image analysis, restoration, and compression. While there has been a drive to increase the representation ability of these methods via directional filters or elongated basis functions, they still have been focused on essentially p...

Beamlets are a special dyadically organized collection of line segments, exhibiting a range of lengths, positions and orientations. This collection is relatively compact: there are O(n log2(n)) beamlets, compared to O(n) line segments. This collection is relatively expressive: up to a certain tolerance, it does not take more than O(log2(n)) beamlets to approximate a single line segment. Because...

In multi-objective radiotherapy planning, we are interested in Pareto surfaces of dimensions 2 up to about 10 (for head and neck cases, the number of structures to trade off can be this large). A key question that has not been answered yet is: how many plans does it take to sufficiently represent a high-dimensional Pareto surface? In this paper, we present a method to answer this question, and ...

The ffx code was used to investigate the lifetime and propellant throughput capability of the High Power Electric Propulsion (HiPEP) thruster ion optics as part of NASA’s Project Prometheus. Erosion predictions are presented as a function of beamlet current, accel grid voltage, and propellant utilization efficiency. These predictions were then compared to the lifetime goals of the thruster, and...

An energetic helium neutral beam is involved in the beam neutralization measurement system of alpha particles confined in a DT fusion plasma. A full size strong-focusing He(+) ion source (2 A, the beam radius of 11.3 mm, the beam energy less than 20 keV). Present strong-focusing He(+) ion source shows an emittance diagram separated for each beamlet of multiple apertures without phase space mixi...

Immigrants gaining economic security tend to reinforce—not relinquish—their ethnic identification [Halter M. Shopping for identity: the marketing of ethnicity. New York: Schoken Books, 2000. p. 256.]. Shopping is one avenue where people affirm themselves. Mall shopping has become an expression of personal values. In this research, the authors investigate shopping values [J. Consum. Res. 20 (199...

Abstract:Among the image processing techniques used today, the most basic and important one is edge detection. This forms the base of other processes such as object recognition, segmentation etc. For this, many new techniques have been proposed recently, to improve the edge detection process. The method proposed is an advanced algorithm by improving the already existing edge detection algorithm...