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1997

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Articles 241 - 270 of 2472

Full-Text Articles in Physical Sciences and Mathematics

Determination Of The Michel Parameters And The Τ Neutrino Helicity In Τ Decay, J. P. Alexander, Kenneth A. Bloom, Cleo Collaboration Nov 1997

Determination Of The Michel Parameters And The Τ Neutrino Helicity In Τ Decay, J. P. Alexander, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

Using the CLEO II detector at the Cornell Electron Storage Ring operated at √s =10.6 GeV, we have determined the Michel parameters ρ, ξ, and δ in τ±→l±νν̅ decay as well as the τ neutrino helicity parameter h in τ±→π±π0ν decay. From a data sample of 3.02×106 produced τ pairs we analyzed events of the topologies e+e-→τ+τ-→(l±νν̅)(π±π0ν) and e+e-→τ+τ-→(π±π0ν̅)(π±π0ν). …


Center For Sustainable Agricultural Systems Newsletter, November/December 1997 Nov 1997

Center For Sustainable Agricultural Systems Newsletter, November/December 1997

Center for Sustainable Agricultural Systems: Newsletters (1993-2000)

Contents:

CSAS Publishes Book That Reviews Sustainable Ag Literature

NCR SARE Solicits PDP Proposals

Integrated Farm Update: Impact of Spring-grazing Crop Residues

Education in Scandinavia: from Farming to Food Systems

NSAS 1998 Annual Meetings

Ecosystems Provide Valuable "Services" Worth $33 Trillion

USDA Creates New Office of Pest Management

Sanet-mg Archives: A Valuable Resource


Hands-On Phasors And Multiple-Slit Interference, Rand S. Worland, Matthew J. Moelter Nov 1997

Hands-On Phasors And Multiple-Slit Interference, Rand S. Worland, Matthew J. Moelter

Physics

No abstract provided.


An Investigation Into The Use Of Software Product Metrics For Cobol Systems, Richard E. Boone Nov 1997

An Investigation Into The Use Of Software Product Metrics For Cobol Systems, Richard E. Boone

Theses and Dissertations

This thesis investigated several hypotheses that specific product measures could be used to predict later software lifecycle process or product measures. It collected software product and process measures from four consecutive major releases of a large Cobol legacy system (400K LOC). The types of product measures used were size and specific complexity measures. A statistical software package was used to calculate sample correlation coefficients between the measures. A 95% confidence interval was computed for each sample correlation coefficient that showed a strong or moderate linear correlation. The maintenance process measures provided were manhours used for each program changed or added, …


Updated Measurement Of The Τ Lepton Lifetime, R. Barate, Manoj Thulasidas Nov 1997

Updated Measurement Of The Τ Lepton Lifetime, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A new measurement of the mean lifetime of the τ lepton is presented. Three different analysis methods are applied to a sample of 90000 τ pairs, collected in 1993 and 1994 with the ALEPH detector at LEP. The average of this measurement and those previously published by ALEPH is ττ = 290.1±1.5±1.1fs.


Dispersion Coefficients For Highly Excited Molecular States Of K2, Mircea Marinescu, Anthony F. Starace Nov 1997

Dispersion Coefficients For Highly Excited Molecular States Of K2, Mircea Marinescu, Anthony F. Starace

Anthony F. Starace Publications

We report results of theoretical calculations for the dispersion coefficients associated with the long-range interaction of two 39K atoms in the states 39K(4s)- 39K(5d,6d,7s). These results have been found by Wang et al. [Phys. Rev. Lett. 78, 4173 (1997)] to be in a good agreement with their measurements.


Analysis Of Uranium Oxide Weathering By Molecular Spectroscopy, Matthew S. Zickafoose Nov 1997

Analysis Of Uranium Oxide Weathering By Molecular Spectroscopy, Matthew S. Zickafoose

Theses and Dissertations

A preliminary study of the weathering of uranium oxide particles diluted in diamond dust at ambient environmental conditions is presented. The primary weathering reaction is oxidation of the uranium from the 4 to 6 oxidation state, although formation of compounds such as carbonates and hydroxides is possible. Identification of the state of uranium oxide has been attempted using luminescence spectroscopy and diffuse reflectance Fourier transform infrared spectroscopy DRIFTS. Luminescence spectra of nominal samples of three common oxides, UO3, U3O8, and UO2, have been measured showing significant spectral differences in peaks at 494 nm, 507 nm, 529 nm, and 553 nm. …


Salinity And Hydrology Of The Mills Lake Catchment, R Ferdowsian, A T. Ryder Nov 1997

Salinity And Hydrology Of The Mills Lake Catchment, R Ferdowsian, A T. Ryder

Resource management technical reports

The Mills Lake Catchment is located north of the Ongerup-Jerramungup Road, 35 km west of Jerramungup and 10 km north-east of Ongerup. It covers about 23,800 ha of agricultural land that is more than 90% cleared and predominantly cropped. The average annual rainfall of the catchment is about 370 mm. Many low-lying parts of the study area have become salt-affected during recent years. The extent of soil salinity is growing rapidly and it is feared that, without any treatment, more land will become salt-affected.


Simulation Study Of Learning Automata Games In Automated Highway Systems, Cem Unsal, Pushkin Kachroo, John S. Bay Nov 1997

Simulation Study Of Learning Automata Games In Automated Highway Systems, Cem Unsal, Pushkin Kachroo, John S. Bay

Electrical & Computer Engineering Faculty Research

One of the most important issues in Automated Highway System (AHS) deployment is intelligent vehicle control. While the technology to safely maneuver vehicles exists, the problem of making intelligent decisions to improve a single vehicle’s travel time and safety while optimizing the overall traffic flow is still a stumbling block. We propose an artificial intelligence technique called stochastic learning automata to design an intelligent vehicle path controller. Using the information obtained by on-board sensors and local communication modules, two automata are capable of learning the best possible (lateral and longitudinal) actions to avoid collisions. This learning method is capable of …


Searches For Scalar Top And Scalar Bottom Quarks At Lep2, Barate, R.; Et Al., M. Thulasidas Nov 1997

Searches For Scalar Top And Scalar Bottom Quarks At Lep2, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

Searches for scalar top and bottom quarks have been performed with data collected by the ALEPH detector at LEP. The data sample consists of 21.7 pb−1 taken at √ s = 161, 170, and 172 GeV and 5.7 pb−1 taken at √ s = 130 and 136 GeV. No evidence for scalar top quarks or scalar bottom quarks was found in the channels ˜t → cχ, ˜t → bℓν˜, and b˜ → bχ. For the channel ˜t → cχ a limit of 67 GeV/c 2 has been set on the scalar top quark mass, independent of the mixing angle between …


Tertiary Storage In Multimedia Systems: Staging Or Direct Access?, Hwee Hwa Pang Nov 1997

Tertiary Storage In Multimedia Systems: Staging Or Direct Access?, Hwee Hwa Pang

Research Collection School Of Computing and Information Systems

Multimedia applications that are required to manipulate large collections of objects are becoming increasingly common. Moreover, the size of multimedia objects, which are already huge, are getting even bigger as the resolution of output devices improve. As a result, many multimedia storage systems are not likely to be able to keep all of their objects disk-resident. Instead, a majority of the less popular objects have to be off-loaded to tertiary storage to keep costs down. The speed at which objects can be accessed from tertiary storage is thus an important consideration. In this paper, we propose an adaptive data retrieval …


Task Scheduling In Networks, Cynthia Phillips, Clifford Stein, Joel Wein Nov 1997

Task Scheduling In Networks, Cynthia Phillips, Clifford Stein, Joel Wein

Dartmouth Scholarship

Scheduling a set of tasks on a set of machines so as to yield an efficient schedule is a basic problem in computer science and operations research. Most of the research on this problem incorporates the potentially unrealistic assumption that communication between the different machines is instantaneous. In this paper we remove this assumption and study the problem of network scheduling, where each job originates at some node of a network, and in order to be processed at another node must take the time to travel through the network to that node.

Our main contribution is to give approximation algorithms …


Comparisons Of Gears And Vessels Used In The Virginia Institute Of Marine Science Juvenile Finfish Trawl Survey, David Hata Nov 1997

Comparisons Of Gears And Vessels Used In The Virginia Institute Of Marine Science Juvenile Finfish Trawl Survey, David Hata

Reports

The Virginia Institute of Marine Science (VIMS) currently conducts a monthly trawl survey in the three major Virginia rivers and the lower Chesapeake Bay to estimate the abundance of economically important finfish species, particularly at the juvenile stage .. VIM:S has conducted similar trawl surveys in various forms since 1955. Although this represents a 40 year period, variations in sampling design and gear have confounded efforts to produce a meaningful, continuous time series. Such variations include changes in stations occupied, sampling frequency, _vessels, and trawl gears. Much of the trawl survey sampling has been documented (Wojcik and Van Engel 1988a, …


A Simple Formula For Pi, V. Adamchik, Stan Wagon Oct 1997

A Simple Formula For Pi, V. Adamchik, Stan Wagon

Stan Wagon, Retired

No abstract provided.


An Integrated Environment For Problem Solving And Program Development, Fadi Pierre Deek Oct 1997

An Integrated Environment For Problem Solving And Program Development, Fadi Pierre Deek

Dissertations

A framework for an integrated problem solving and program development environment that addresses the needs of students learning programming is proposed. Several objectives have been accomplished: defining the tasks required for program development and a literature review to determine the actual difficulties involved in learning those tasks. A comprehensive Study of environments and tools developed to support the learning of problem solving and programming was then performed, covering programming environments, debugging aids, intelligent tutoring systems, and intelligent programming environments. This was followed by a careful analysis and critique of these systems, which uncovered the limitations that have prevented them from …


Modeling Study On The Neopentyl+ O2 Reaction System And Experimental And Modeling Study On Mtbe Pyrolysis And Oxidation, Ru Wei Oct 1997

Modeling Study On The Neopentyl+ O2 Reaction System And Experimental And Modeling Study On Mtbe Pyrolysis And Oxidation, Ru Wei

Dissertations

A modeling study on neopentyl radical + O2 reaction system is conducted in this study. Thermodynamic parameters on all species and important transition states are calculated. A thermochemical kinetic analysis is performed.

Thermodynamic parameters are estimated using group additivity with HBI groups. Transition state energies are evaluated from experimental and theoretical data in the literature, combined with elementary reaction modeling to account for temperature effects. Transition state structures, vibration frequencies and entropies are determined from semi-empirical calculations, MOPAC PM3. Kinetics are analyzed with quantum RRK theory for k(E) coupled with modified strong collision analysis of Gilbert et al for …


Diffusive And Wavelike Phenomena In Thermal Processing Of Materials, John A. Pelesko Oct 1997

Diffusive And Wavelike Phenomena In Thermal Processing Of Materials, John A. Pelesko

Dissertations

Contemporary materials science abounds with novel processing methods. Devices such as lasers, microwave sources, and electron beam guns, provide unprecedented control over the deposition of energy within a material. The modern materials scientist has the ability to deposit energy volumetrically, to precisely control the location of energy deposition within a material, and to deposit energy in extremely short intervals of time. While making possible numerous thermal processing methods, these devices also push the limits of our understanding of the response of materials to energy deposition. In order to optimize and control these processing methods, it becomes necessary to further our …


Hybrid Quantum And Molecular Mechanics Embedded Cluster Models For Chemistry On Silicon And Silicon Carbide Surfaces, James R. Shoemaker Oct 1997

Hybrid Quantum And Molecular Mechanics Embedded Cluster Models For Chemistry On Silicon And Silicon Carbide Surfaces, James R. Shoemaker

Theses and Dissertations

Fabrication of silicon carbide SiC semiconductor devices are of interest for aerospace applications because of their high-temperature tolerance. Growth of an insulating SiO2 layer on SiC is a poorly understood process, and sometimes produces interface defects that degrade device performance. Accurate theoretical models of surface chemistry, using quantum mechanics QM, do not exist because of the huge computational cost of solving Schroedingers equation for a molecular cluster large enough to represent a surface. Molecular mechanics MM, which describes a molecule as a collection of atoms interacting through classical potentials, is a fast computational method, good at predicting molecular structure, …


Interactive And Batch Creation Of Oodb Medical Vocabularies, Muhammad Arif Oct 1997

Interactive And Batch Creation Of Oodb Medical Vocabularies, Muhammad Arif

Theses

Controlled vocabularies are becoming popular for knowledge representation and querying. They are particularly helpful in the medical field since they can unify disparate terminologies and provide information in a compact, comprehensible manner. In this thesis, we present a mechanism to create OODB controlled medical vocabularies from flat-file format. We also describe a tool by which a user can interactively create, edit and browse the vocabulary. For better understanding of the structure of the vocabulary we designed our interface as a graphical editor and browser. The user of this interface will typically be a medical expert who either wants to add …


Structured Document Comparison And Scientific Data Mining On The World Wide Web, Philip B. Johnson Oct 1997

Structured Document Comparison And Scientific Data Mining On The World Wide Web, Philip B. Johnson

Theses

The usefulness and accessibility of programs and systems have become important issues for users and researchers alike. A program's usefulness can lw measured by the frequency with which it is used. From the author's or maintainer's point of view, the frequency of usage can be determined by how often a request for the software is received. In the past, a user became aware of a particular tool through various means, and contacted the author or maintainer to obtain a copy of it. This presented difficulties, ranging from language barriers to machine incompatibilities to control of the use of the program. …


Testing Statistical Significance In Sequence Classification Algorithms, Tom Tien-Hua Shih Oct 1997

Testing Statistical Significance In Sequence Classification Algorithms, Tom Tien-Hua Shih

Theses

Multiple sequence alignment has proven to be a successful method of representing and organizing of protein sequence data. It is crucial to medical researches on the structure and function of proteins.

There have been numerous tools published on how to abstract meaningful relationship from an unknown sequence and a set of known sequences. One study used a method for discovering active motifs in a set of related protein sequences. These are meaningful knowledge abstracted from the known protein database since most protein families are characterized by multiple local motifs. Another study abstracts knowledge regarding the input sequence using a preconstructed …


Analysis Of The Protocol For The Handover In A Micro-Cell Packet Switched Mobile Network, Anna M. Thomas Oct 1997

Analysis Of The Protocol For The Handover In A Micro-Cell Packet Switched Mobile Network, Anna M. Thomas

Theses

The overlay of microcells over macrocells offers new opportunities and is cost effective, which makes the handover in such a micro-cellular environment an important issue. The objective of this study is to analyze and prove the truthfulness of a new protocol proposed, which guarantees no packet loss during the handoff. The study here emphasizes on the data integrity issue, since it is the key factor affecting the throughput performance of the transport layer. It is shown that usage of the Internet Protocol leads to packet loss in the presence of handover. Simulation results reveal that the proposed new protocol preserves …


Removal And Recovery Of Vocs And Oils From Surfactant-Flushed Recovered Water By Membrane Permeation, Ashish Nagnath Saraf Oct 1997

Removal And Recovery Of Vocs And Oils From Surfactant-Flushed Recovered Water By Membrane Permeation, Ashish Nagnath Saraf

Theses

Surfactant-enhanced subsurface remediation appears to be capable of removing efficiently contaminants from the source area as well as the concentrated plume. Initial research was conducted on separate removal of trichloroethylene (TCE) and an oil. It was found that oil permeation and modified pervaporation are effective techniques of removing oil and TCE respectively from the simulated feed. It was found that the oil permeation technique can effectively remove 98-99% of oil from an oil-in-water emulsion. The subsurface-entrapped organic pollutants often have high boiling components along with the VOCs. A combined permeation technique is applied here to simultaneously remove TCE and n-dodecane …


Algorithms And Tools For Splicing Junction Donor Recognition In Genomic Dna Sequences, Maisheng Yin Oct 1997

Algorithms And Tools For Splicing Junction Donor Recognition In Genomic Dna Sequences, Maisheng Yin

Theses

The consensus sequences at splicing junctions in genomic DNA are required for pre-mRNA breaking and rejoining which must be carried out precisely. Programs currently available for identification or prediction of transcribed sequences from within genomic DNA are far from being powerful enough to elucidate genomic structure completely[4]. In this research, we develop a degenerate pattern match algorithm for 5' splicing site (Donor Site) recognition.. Using the Motif models we developed, we can mine out the degenerate pattern information from the consensus splicing junction sequences. Our experimental results show that, this algorithm can correctly recognize 93% of the total donor sites …


Port Everglades Macroinvertebrate Monitoring: Monitoring Of Benthic Macroinvertebrate Assemblages At The Southport Turning Basin And Adjacent Areas Of John U. Lloyd State Recreation Area: Final Report, Charles G. Messing, Richard E. Dodge Oct 1997

Port Everglades Macroinvertebrate Monitoring: Monitoring Of Benthic Macroinvertebrate Assemblages At The Southport Turning Basin And Adjacent Areas Of John U. Lloyd State Recreation Area: Final Report, Charles G. Messing, Richard E. Dodge

Marine & Environmental Sciences Faculty Reports

Monitoring of benthic macroinvertebrate assemblages in the vicinity of Port Everglades Southport began in September 1988 in anticipation of dredging of the Southport Turning Notch and concomitant mitigation of mangrove habitats at adjacent areas of John U. Lloyd State Recreation Area. Twice-yearly surveys were carried out from September 1988 to January 1991 by Sheldon Dobkin (Florida Atlantic University), and subsequently, from August 1991 to January 1997, under the supervision of Charles G. Messing and Richard E. Dodge (Nova Southeastern University Oceanographic Center). From 1990 onward, surveyed sites consisted of 11 Ponar grab stations, 11 mangrove crab census stations, and three …


Terrestrial Natural Communities Of Nebraska - Version I, Gerry Steinauer, Steven B. Rolfsmeier Oct 1997

Terrestrial Natural Communities Of Nebraska - Version I, Gerry Steinauer, Steven B. Rolfsmeier

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

The Nebraska Natural Heritage Program has been collecting information and data including published literature, field observations and vegetation plot data over the last 10 years of development of Nebraska’s natural community classification. The classification contains 27 wetland and 36 upland communities including forest, woodland, shrubland, herbaceous, and sparsely vegetated (e.g. rock outcrop) types. The community types were distinguished primarily on plant species composition and to a lesser extent on soils, hydrology and geographic location. The classification contains descriptions of each community type that include dominant species, soils, range, and other ecological information. The classification is designed to be flexible enough …


A Control Basis For Learning Multifingered Grasps, Jefferson Coelho, Roderic Grupen Oct 1997

A Control Basis For Learning Multifingered Grasps, Jefferson Coelho, Roderic Grupen

Roderic Grupen

In this paper, we introduce a robust controller that uses contact position and normal feedback to generate contact configurations for statically stable grasps. The approach uses a context sensitive composition of two controllers that minimize force and moment residuals in the grasp configuration. We show that equilibria in the composite controller correspond to optimal contact configurations for 2 and 3 contacts on regular, convex polygons. The preimage is used to generalize the controller to arbitrary object geometries by learning a policy for compensation and to address object recognition, and contact (de)allocation.


Materialized View Algorithms, Yubo Fan Oct 1997

Materialized View Algorithms, Yubo Fan

Dissertations and Theses

A data warehouse is a stand-alone repository of integrated information available for decision support OLAP querying and analysis. Aggregate views can be materialized (stored in disk) to improve query performance in a data warehouse.

Several static and dynamic algorithms for selecting materialized aggregate views (MA V) in a data warehouse are proposed in this thesis. The algorithms are then compared by running a simulation system, which can be configured to compare several algorithms on different type of data warehouses. Simulation results for static algorithms are presented to show that several proposed algorithms perform close to an existing good algorithm (HRU …


Major Features Of Glaciochemistry Over The Last 110,000 Years In The Greenland Ice Sheet Project 2 Ice Core, Qinzhao Yang, Paul Andrew Mayewski, Marks S. Twickler, Sallie Whitlow Oct 1997

Major Features Of Glaciochemistry Over The Last 110,000 Years In The Greenland Ice Sheet Project 2 Ice Core, Qinzhao Yang, Paul Andrew Mayewski, Marks S. Twickler, Sallie Whitlow

Earth Science Faculty Scholarship

Major chemical species (Cl, NO 3 - , SO 4 2 - , Na+, NH 4 + , K+, Mg2+, Ca2+) and δ18O covering the last 110,000 years from the Greenland Ice Sheet Project 2 (GISP2) ice core were utilized in this study in order to reconstruct the soluble chemistry of the atmosphere over Greenland and interpret major climate events that have affected the region. During the Holocene the major chemical species and δ18O do not display any significant relationship. However, a strong inverse correlation was …


Hybrid Reflection-Transmission Surface Light-Scattering Instrument With Reduced Sensitivity To Surface Sloshing, William V. Meyer, James A. Lock, Michael Cheung, Thomas W. Taylor, Padetha Tin, J. Adin Mann Jr. Oct 1997

Hybrid Reflection-Transmission Surface Light-Scattering Instrument With Reduced Sensitivity To Surface Sloshing, William V. Meyer, James A. Lock, Michael Cheung, Thomas W. Taylor, Padetha Tin, J. Adin Mann Jr.

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

A hybrid reflection-transmission surface light-scattering instrumental design is presented, examined theoretically, and tested experimentally. The purpose of the design is to reduce the sensitivity of the instrument to vibration in general and surface sloshing in particular while sacrificing Little performance. Traditional optical arrangements and two new optical configurations with varying trade-offs between slosh resistance and instrumental simplicity and accuracy are examined by use of Fourier optics methods. The most promising design was constructed and tested with acetone, ethanol, and water as subject fluids. The test involved backcalculation of the wave number of the capillary wave examined with the known physical …