Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

schools within 5 miles of other schools”) in addition to the general case that the two point-sets are distinct. Our law holds for many
real datasets, including diverse environments (geographic datasets, feature vectors from biology data, galaxy data from astronomy).
In addition, we introduce the concept of the Box-Occupancy-Product-Sum (BOPS) plot, and we show that it can compute
the pair-count exponent in a timely manner, reducing the run time by orders of magnitude, from quadratic to linear. Due to the
pair-count exponent and our analysis (Law 1), we can achieve accurate selectivity estimates in constant time (0(1)) without the
need for sampling or other expensive operations. The relative error in selectivity is about 30% with our fast BOPS method, and
even better (about 10%), if we use the slower, quadratic method.
DTIC
Spatial Distribution; Probability Distribution Functions; Information Retrieval; Data Mining
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SYSTEMS ANALYSIS AND OPERATIONS RESEARCH
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20000063528 Army Engineer Research and Development Center, Environmental Lab., Vicksburg, MS USA
Simulating Population Dynamics in an Ecosystem Context Using Coupled Eulerian-Lagrangian Hybrid Models (CEL
HYBRID Models) Final Report
Nestler, John M.; Goodwin, R. A.; Apr. 2000; 44p; In English
Report No.(s): AD-A377014; ERDC/EL-TR-00-4; No Copyright; Avail: CASI; A03, Hardcopy; A01, Microfiche
Management and modification of water resources (e.g., construction of instream structures, regulatory actions, operating
strategies, etc.) have a profound effect on the physico-chemical environment of aquatic ecosystems and on the living resources
that depend on this environment. CEL HYBRID models are a new method for coupling Eulerian and Lagrangian reference frames
so that the higher trophic levels of an aquatic ecosystem, such as fish and shellfish, can be systematically and realistically simulated.
The Eulerian-Lagrangian couple works as follows: the influence of aquatic organisms on water quality is evaluated by spatially
averaging relevant characteristics of the organisms within a cell (an Eulerian concept), such as biomass, while the population
dynamics of individual species (e.g., reproduction, recruitment, feeding, migration, and/or mortality) are modeled by treating
organisms as individuals or groups of individuals (a Lagrangian concept). Water quality is often analyzed using spatially averaged
cells, where each cell represents one uniform environment, with no variation in attributes within the cell. On the other hand, the
population dynamics of species are often analyzed by tracking individuals, or groups of individuals, all of which are considered
to reside within one spatially averaged environment. Spatially averaging characteristics, such as mass, of a group of organisms’
participation in the chemical processes of the aquatic environment, such as dissolved oxygen uptake and excretion, to be evaluated.
However, species population dynamics, which determine the number of organisms in each cell, are usually modeled with a Lagrangian
reference frame. CEL HYBRID models allow for the analysis of higher trophic level processes with minimal distortion and
loss of information by coupling the two frames of reference and, thereby, exploiting the advantages and minimizing the disadvantages
associated with each.
DTIC
Populations; Population Theory; Probability Theory; Ecosystems; Marine Environments; Water Management; Water Resources;
Water Quality
20000064091 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA USA
Science Application Teams
[2000]; 22p; In English; No Copyright; Avail: CASI; A03, Hardcopy; A01, Microfiche
This paper discusses the science application team activities. Science Application team are: (1) Represent the diversity of
NASA onboard computing of the future. (2) Drive architecture and system software requirements. (3) Demonstrate the benefit
of highly capable computing onboard. (4) Study the birth of the first galaxies. (5) Study formation of stars. (6) Discusses the next
generation space telescope hardware/software requirement: image processing and on-board optical calibration. Also discusses
gamma ray large area space telescope; orbital thermal imaging spectrometer; solar terrestrial probe program; autonomous Mars
rover;fault tolerance and errors.
CASI
Computer Programs; Galaxies; Gamma Rays; Imaging Spectrometers; Thermal Mapping; Architecture (Computers)