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2002

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Articles 1921 - 1950 of 3435

Full-Text Articles in Physical Sciences and Mathematics

Experimenting With Server-Aided Signatures, Xuhua Ding, D. Mozzacchi, Gene Tsudik Feb 2002

Experimenting With Server-Aided Signatures, Xuhua Ding, D. Mozzacchi, Gene Tsudik

Research Collection School Of Computing and Information Systems

This paper explores practical and conceptual implications of using Server-Aided Signatures (SAS). SAS is a signature method that relies on partiallytrusted servers for generating public key signatures for regular users. Besides its two primary goals of 1) aiding small, resource-limited devices in computing heavy-weight (normally expensive) digital signatures and 2) fast certificate revocation, SAS also o#ers signature causality and has some interesting features such as built-in attack detection for users and DoS resistance for servers.


Coordination Using Logical Operators In Linda, James Kendall Snyder Feb 2002

Coordination Using Logical Operators In Linda, James Kendall Snyder

Theses and Dissertations

During the past 20 years, research in coordination has had success in demonstrating that distributed systems are made of two distinct parts: computation and coordination. One of the models that has contributed to the success of coordination is LINDA. While it is an extremely powerful coordination model, LINDA has limitations expressing parallel access to tuple spaces. This thesis proposes an extension to LINDA called LOGOP LINDA which combines tuple spaces using logical operators and thus enabling a single primitive to access multiple tuple spaces in parallel. Essentially this concept replaces serial access to multiple tuple spaces using the same primitive, …


Surface Water Quality - 2001 Hillsborough County, Florida Raw Data Summary, Tom Cardinale Feb 2002

Surface Water Quality - 2001 Hillsborough County, Florida Raw Data Summary, Tom Cardinale

Reports

The Environmental Protection Commission of Hillsborough County (EPC) is charged with the responsibility of monitoring the quality of surface water in the county. The data and information collected enables staff to determine pollution status and trends throughout Tampa Bay and it's tributaries. The data is also widely distributed to other government agencies, academia, the local scientific community and the general public. EPC's routine monthly surface water monitoring began in January of 1972, with the Tampa Bay estuary and was expanded to maj or rivers and streams in 1973. This report is a tabulation of the raw data produced on surface …


A New Theory Of Premixed Flames In Near-Stoichiometric Mixtures, Eliana S. Antoniou Jan 2002

A New Theory Of Premixed Flames In Near-Stoichiometric Mixtures, Eliana S. Antoniou

Dissertations

In this dissertation, a new model of premixed flames in near-stoichiometric mixtures is derived. Unlike most previous theories, which are valid only for very lean or very rich, i.e. off-stoichiometric conditions, our model remains valid over the entire spectrum of mixture compositions, from lean to rich, including the near-stoichiometric regime. Since fuel-mixture composition is known to have a significant effect on flame behavior, such a model is expected to contribute new insights into classical problems in premixed combustion.

In the first part of this dissertation, we describe the derivation of a model for premixed flames in two-reactant mixtures in a …


Simultaneous Removal Of Ortho-Dichlorobenzene And Ethanol Vapors In A Biotrickling Filter : Experimental Results And Process Modeling, Suchismita Bhattacharya Jan 2002

Simultaneous Removal Of Ortho-Dichlorobenzene And Ethanol Vapors In A Biotrickling Filter : Experimental Results And Process Modeling, Suchismita Bhattacharya

Dissertations

This study investigated the possibility of simultaneous removal of vapors of dissimilar volatile organic compounds from air streams in a biotrickling filter (BTF). Using a rricrobial consortium known to utilize ortho-dichlorobenzene (o-DCB) as sole carbon and energy source, a culture was developed on o-DCB/ethanol mixtures and a BTF unit was developed and operated with air streams carrying o-DCB and ethanol vapors. Simultaneous removal of the two compounds was observed in experiments that span a period of over three years.

Experiments were performed at air residence times ranging from 4 to 6.5 min, liquid flow rates from 3.6 to 9 Lh …


Development Of Analytical Systems And Monitoring Of Vocs Emissions During Polymer Processing, Qin Xiang Jan 2002

Development Of Analytical Systems And Monitoring Of Vocs Emissions During Polymer Processing, Qin Xiang

Dissertations

A method using direct flame ionization detector (FID) measurement was developed to study total volatile organic compounds (VOCs) emissions during thermal degradation of polymers. This was used to estimate organic emissions from both virgin polymer resins and commingled plastics. The effects of process parameters, i. e., temperature, heating rate and residence time, were also studied. Significant VOCs emissions were observed at normal processing temperatures, particularly from recycled polymers. Each polymer showed a distinct evolution pattern during its thermal degradation. Kinetics of VOCs emissions were also studied using a non-isothermal technique. The kinetic parameters were in agreement with data from the …


Modeling Hydrogen Diffusion For Solar Cell Passivation And Process Optimization, Yi Zhang Jan 2002

Modeling Hydrogen Diffusion For Solar Cell Passivation And Process Optimization, Yi Zhang

Dissertations

A diffusion model for hydrogen (H) in crystalline silicon was established which takes into account the charged state conversion, junction field, mobile traps, and complex formation and dissociation at dopant and trap sites. Carrier exchange among the various charged species is a "fast" process compared to the diffusion process. A numerical method was developed to solve the densities of various charged species from the Poisson's equation that involves shallow-level dopants and one "negative U" impurity, e.g., H. Time domain implicit method was adopted in finite difference scheme to solve the fully coupled equations.

Limiting versions of the model were applied …


Structural Transitions In Biomolecules - A Numerical Comparison Of Two Approaches For The Study Of Phase Transitions In Small Systems, Nelson A. Alves, Ulrich H.E Hansmann, Yong Peng Jan 2002

Structural Transitions In Biomolecules - A Numerical Comparison Of Two Approaches For The Study Of Phase Transitions In Small Systems, Nelson A. Alves, Ulrich H.E Hansmann, Yong Peng

Michigan Tech Publications

We compare two recently proposed methods for the characterization of phase transitions in small systems. The usefulness of these techniques is evaluated for the case of structural transition in alanine-based peptides.


Consequence Of Superfluidity On The Expansion Of A Rotating Bose-Einstein Condensate, Mark Edwards, Charles W. Clark, P. Pedri, L. Pitaevskii, S. Stringari Jan 2002

Consequence Of Superfluidity On The Expansion Of A Rotating Bose-Einstein Condensate, Mark Edwards, Charles W. Clark, P. Pedri, L. Pitaevskii, S. Stringari

Department of Physics and Astronomy Faculty Publications

We propose an easily detectable signature of superfluidity in rotating, vortex-free gaseous Bose-Einstein condensates. We have studied the time evolution of the expansion of such a condensate after it is released from the confining trap. We find that if such a condensate is not initially rotating, then at some moment it will instantaneously achieve a circular cross section. If the condensate is initially rotating its irrotational flow and the conservation of angular momentum prevent the released condensate from attaining a circular cross section, since the instantaneous moment of inertia is then proportional to the asymmetry of this cross section.


A Comparison Of Potential Labor-Saving Sampling Methods For Assessing Large Mammal Damage In Corn, Richard . M. Engeman, Ray T. Sterner Jan 2002

A Comparison Of Potential Labor-Saving Sampling Methods For Assessing Large Mammal Damage In Corn, Richard . M. Engeman, Ray T. Sterner

United States Department of Agriculture Wildlife Services: Staff Publications

Accurate estimation of crop damage by wildlife often requires labor-intensive sampling procedures. Variable area transect (VAT) sampling has been identified as a potential labor-saving alternative to quadrat sampling. We fully enumerated all damaged corn plants in a field to assess accuracy of sampling by small quadrats 5m long by one or two row-widths, and by VAT sampling with searches from random starting points to the 3rd, 4th, 5th, and 6th damaged plant. Two widths for strip transects also were considered for VAT sampling: one and two crop rows. Two analytical formulae were considered for the VAT data. Thus, 18 estimates …


Comparative Molecular Field Analysis (Comfa) Of Protonated Methylphenidate Phenyl-Substituted Analogs, Kathleen Mary Gilbert Jan 2002

Comparative Molecular Field Analysis (Comfa) Of Protonated Methylphenidate Phenyl-Substituted Analogs, Kathleen Mary Gilbert

Theses

Protonated methylphenidate (pMP) and several phenyl-substituted pMP analogs were analyzed using Comparative Molecular Field Analysis (CoMFA) to develop a pharmacophore for dopamine transporter (DAT) binding. This research is a part of an interdisciplinary study on using methylphenidate (MP) analogs to block the binding of cocaine to the DAT as a treatment for addiction.

A random search conformational analysis using key pMP torsional angles was performed to create conformer families representing possible bioactive conformations. The lowest energy pMP conformer of each family was used as a template to create phenyl-substituted pMP analogs.

Partial least squares analysis was used to determine the …


Simulation And Close-To-Optimal Algorithm For The Static Load Balancing Of A Network Of Heterogeneous Processors, Mark G. Steiner Jan 2002

Simulation And Close-To-Optimal Algorithm For The Static Load Balancing Of A Network Of Heterogeneous Processors, Mark G. Steiner

Theses

A close-to-optimal linear programming-based algorithm for the static load balancing of a network of heterogeneous processors is described and implemented. Experimental results suggest that the amount of time required by the implementation of the algorithm to balance the loads of the servers as a function of the number of servers has polynomial complexity.


Short-Term Community Based Dune Management Activities On A Highly Developed Coast In New Jersey, Stacy Mccormack Jan 2002

Short-Term Community Based Dune Management Activities On A Highly Developed Coast In New Jersey, Stacy Mccormack

Theses

Recently, local governments have started to realize the effectiveness of dune building as a form of hazard mitigation and have engineered dunes for this purpose. This study evaluates dune management at the local level; specifically, short term management practices, physical constraints, dune management participants, and sources of guidance. A review of municipal regulations, topographic surveys, and interviews with local officials were conducted in four New Jersey communities: Belmar, Spring Lake, Sea Girt and Manasquan. The results of this study indicate that dunes were established as part of local hazard mitigation planning in response to the 1992 storm, and topographic surveys …


Nontunneling High-Order Harmonics From Ultra-Intense Laser-Driven Tightly Bound Systems, S. X. Hu, Anthony F. Starace, W. Becker, W. Sandner, D. B. Milosevic Jan 2002

Nontunneling High-Order Harmonics From Ultra-Intense Laser-Driven Tightly Bound Systems, S. X. Hu, Anthony F. Starace, W. Becker, W. Sandner, D. B. Milosevic

Anthony F. Starace Publications

High-order harmonic emission is investigated by numerical solution of the weakly relativistic, two-dimensional Schrödinger equation for the case of ultra-intense laser-driven tightly bound systems (for example, multiply charged ions such as O7+ exposed to laser fields of the order of 1018 W cm-2 at 248 nm). In contrast to their usual substantial decrease, the low-order harmonics having an energy less than the ionization potential exhibit a high efficiency (i.e. intense) plateau with a well defined cutoff. The shape of this plateau is found to depend on the shape of the binding potential. A classical “surfing” mechanism for …


A Tool For Phylogenetic Data Cleaning And Searching, Viswanath Neelavalli Jan 2002

A Tool For Phylogenetic Data Cleaning And Searching, Viswanath Neelavalli

Theses

Data collection and cleaning is a very important part of an elaborate Data Mining System. 'TreeBASE' is a relational database of phylogenetic information at the Harvard University with a keyword based searching interface. 'TreeSearch' is a Structure based search engine implemented at NJIT that can be used for searching phylogenetic data. Phylogenetic trees are extracted from the flat-file database at Harvard University, available at {ftp://herbaria.harvard.edu/pub/piel/Data/files/}. There is huge amount of information present in the files about the trees and the data matrices from which the trees are generated. The search tool implemented at NJIT is interested in using the string …


A Review And Assessment Of Novice Learning Tools For Problem Solving And Program Development, Christopher John Bladek Jan 2002

A Review And Assessment Of Novice Learning Tools For Problem Solving And Program Development, Christopher John Bladek

Theses

There is a great demand for the development of novice learning tools to supplement classroom instruction in the areas of problem solving and program development. Research in the area of pedagogy, the psychology of programming, human-computer interaction, and cognition have provided valuable input to the development of new methodologies, paradigms, programming languages, and novice learning tools to answer this demand.

Based on the cognitive needs of novices, it is possible to postulate a set of characteristics that should comprise the components an effective novice-learning tool. This thesis will discover these characteristics and provide recommendations for the development of new learning …


The Siting Of Regional Sanitary Landfills Or Facilities For Municipal Solid Waste In The Upper Southern Region Of Thailand, Jantira Duangsai Jan 2002

The Siting Of Regional Sanitary Landfills Or Facilities For Municipal Solid Waste In The Upper Southern Region Of Thailand, Jantira Duangsai

Theses

The pollution problem from municipal solid waste in Thailand is serious. Population growth and rapid economic expansion have resulted in a significant increase in the quantity of solid waste. Inadequate provisions for waste collection, shortages of disposal equipment, and the inability of the responsible agencies to find appropriate disposal sites, also are major causes of the present problems. The environmental impacts that result from unsanitary disposal sites have become a serious public concern across the country.

Environmentally protective and publicly acceptable siting of regional sanitary landfills or facilities for municipal solid waste management in the upper southern region of Thailand: …


Airborne Sampling Of Aerosol Particles: Comparison Between Surface Sampling At Christmas Island And P-3 Sampling During Pem-Tropics B, Jack E. Dibb, R. Talbot, Garry Seid, C. E. Jordan, Eric Scheuer, Elliot Atlas, Nicola J. Blake, D R. Blake Jan 2002

Airborne Sampling Of Aerosol Particles: Comparison Between Surface Sampling At Christmas Island And P-3 Sampling During Pem-Tropics B, Jack E. Dibb, R. Talbot, Garry Seid, C. E. Jordan, Eric Scheuer, Elliot Atlas, Nicola J. Blake, D R. Blake

Earth Sciences

Bulk aerosol sampling of soluble ionic compounds from the NASA Wallops Island P-3 aircraft and a tower on Christmas Island during PEM-Tropics B provides an opportunity to assess the magnitude of particle losses in the University of New Hampshire airborne bulk aerosol sampling system. We find that most aerosol-associated ions decrease strongly with height above the sea surface, making direct comparisons between mixing ratios at 30 m on the tower and the lowest flight level of the P-3 (150 m) open to interpretation. Theoretical considerations suggest that vertical gradients of sea-salt aerosol particles should show exponential decreases with height. Observed …


Potent Enantioselective Auxin: Indole-3-Succinic Acid, Daniel W. Armstrong, Yan Song Liu, Lingfeng He, K. Helen Ekborg-Ott, Charles L. Barnes, Charles F. Hammer Jan 2002

Potent Enantioselective Auxin: Indole-3-Succinic Acid, Daniel W. Armstrong, Yan Song Liu, Lingfeng He, K. Helen Ekborg-Ott, Charles L. Barnes, Charles F. Hammer

Chemistry Faculty Research & Creative Works

Low levels of synthetic auxins are used as root growth promoters for a wide variety of botanicals. When properly used, they can produce earlier and more prolific root growth. Indole-3-succinic acid (ISA) is a chiral compound that can be synthesized as a racemate. Its enantiomers were resolved by both chromatography and diastereomeric crystallization. The absolute configuration of each enantiomer was determined by X-ray crystallography and then tested for auxin activity. The relative effectiveness of the ISA enantiomers was determined and compared to the achiral synthetic auxin indole-3-butyric acid and to the natural auxin indole-3-acetic acid.


Electrochemistry And Spectroscopy Of Sulfate And Thiosulfate Complexes Of Iron Porphyrins, Philip Walter Crawford, Michael D. Ryan Jan 2002

Electrochemistry And Spectroscopy Of Sulfate And Thiosulfate Complexes Of Iron Porphyrins, Philip Walter Crawford, Michael D. Ryan

Chemistry Faculty Research and Publications

The electrochemical and spectroscopic properties of the complex formed by the addition of thiosulfate to ferric porphyrins were examined. The NMR spectrum of the thiosulfate–ferric porphyrin complex was consistent with a high-spin ferric complex, while the EPR spectrum at liquid nitrogen temperatures indicated that the complex under these conditions was low-spin. Such behavior has been previously observed for other ferric porphyrin complexes. The visible spectra were characterized by a shift in the Soret band to higher energies, with smaller changes in the longer wavelength region. The complex was reasonably stable in DMF, but slowly reduced over several hours to Fe …


Observation Of Anomalous Spin-State Segregation In A Trapped Ultracold Vapor, Dwight L. Whitaker, H. J. Lewandowski, D. M. Harber, E. A. Cornell Jan 2002

Observation Of Anomalous Spin-State Segregation In A Trapped Ultracold Vapor, Dwight L. Whitaker, H. J. Lewandowski, D. M. Harber, E. A. Cornell

Pomona Faculty Publications and Research

We observe counterintuitive spin segregation in an inhomogeneous sample of ultracold, noncondensed rubidium atoms in a magnetic trap. We use spatially selective microwave spectroscopy to verify a model that accounts for the differential forces on two internal spin states. In any simple understanding of the cloud dynamics, the forces are far too small to account for the dramatic transient spin polarizations observed. The underlying mechanism remains to be elucidated.


Future Directions For Mobile-Agent Research, David Kotz, Robert Gray, Daniela Rus Jan 2002

Future Directions For Mobile-Agent Research, David Kotz, Robert Gray, Daniela Rus

Computer Science Technical Reports

During a discussion in September 2000 the authors examined the future of research on mobile agents and mobile code. (A mobile agent is a running program that can move from host to host in network at times and to places of its own choosing.) In this paper we summarize and reflect on that discussion. It became clear that the field should shift its emphasis toward mobile code, in all its forms, rather than to continue its narrow focus on mobile agents. Furthermore, we encourage the development of modular components, so that application designers may take advantage of code mobility without …


Environmental Quality Monitoring At Five Golf Courses In Miami-Dade County, Lorna Bucknor Jan 2002

Environmental Quality Monitoring At Five Golf Courses In Miami-Dade County, Lorna Bucknor

FIU Electronic Theses and Dissertations

Five golf courses in Miami-Dade County, Florida participated in a one year monitoring study to investigate the environmental impact of agrichemical turf management activities.

Groundwater, soil, surface water, and sediments were sampled quarterly at the golf courses in 1997. Ground and surface water were sampled for 51 pesticide residues (including arsenic), nitrates, and phosphates. Soil and sediments were sampled for arsenic.

Arsenic was the main contaminant of interest. Seventy-five percent of soil samples exceeded the Florida residential soil cleanup target level (CTL) while thirty-two percent of shallow groundwater samples exceeded the maximum contaminant level (MCL). Five other pesticide residues were …


Search For Gluinos And Scalar Quarks In Pp̅ Collisions At √S = 1.8 Tev Using The Missing Energy Plus Multijets Signature, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Jan 2002

Search For Gluinos And Scalar Quarks In Pp̅ Collisions At √S = 1.8 Tev Using The Missing Energy Plus Multijets Signature, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We have performed a search for gluinos () and scalar quarks (q̃,/i>) in a data sample of 84 pb-1 of pp̅ collisions at √s =1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and three or more jets, a characteristic signature in R-parityconserving supersymmetric models. The analysis has been performed “blind,” in that the inspection of the signal region is made only after the predictions from standard model backgrounds have been calculated. Comparing the data with predictions of constrained supersymmetric models, we exclude gluino …


Golay Sequences For Ds Cdma Applications, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki Jan 2002

Golay Sequences For Ds Cdma Applications, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

Golay complementary sequences, often referred to as Golay pairs, are characterised by the property that the sum of their aperiodic autocorrelation functions equals to zero, except for the zero shift. Because of this property, Golay complementary sequences can be utilised to construct Hadamard matrices defining sets of orthogonal spreading sequences for DS CDMA systems of the lengths not necessary being a power of 2. In the paper, we present an evaluation, from the viewpoint of DS CDMA applications of some sets of spreading sequences based on Golay complementary sequences. We then modify those sets of sequences to enhance their correlation …


Measurement Of The Strong Coupling Constant From Inclusive Jet Production At The Tevatron P̅P Collider, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Jan 2002

Measurement Of The Strong Coupling Constant From Inclusive Jet Production At The Tevatron P̅P Collider, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report a measurement of the strong coupling constant, αs(Mz ), extracted from inclusive jet production in pp̅ collisions at √s =1800 GeV. The QCD prediction for the evolution of αs with jet transverse energy ET is tested over the range 40 TET for the renormalization scale. The data show good agreement with QCD in the region below 250 GeV. The value of αs at the mass of the Z0 boson averaged over the range 40 < T < 250 GeV is found to be αs(Mz )= 0.1178 ± 0.0001(stat)-0.0095+0.0081 (expt. syst). The associated theoretical uncertainties …


Stark Shifts And Transition Probabilities In The Ne Ii Spectrum, Stevan Djenize, Vladimir Milosavljevic, Milan S. Dimitrijevic Jan 2002

Stark Shifts And Transition Probabilities In The Ne Ii Spectrum, Stevan Djenize, Vladimir Milosavljevic, Milan S. Dimitrijevic

Articles

Stark shifts (d) and transition probabilities of the spontaneous emission (Einstein's A values) of forty two singly charged neon ( ) ion spectral lines have been measured in a linear, low pressure, pulsed arc at 35 300 K electron temperature and 1.83 10 23 m -3 electron density. Transition probabilities have been obtained using the relative line intensity ratio (RLIR) method. Stark shift values have also been calculated, using the semiclassical perturbation formalism (SCPF). The measured and calculated shift values and the measured A values have been compared to the existing data taken from available data sources.


Collision-Induced Electronic Energy Transfer From V=0 Of The E(0+G) Ion-Pair State In I2: Collisions With He And Ar, Christopher J. Fecko , '98, Miriam Arak Freedman , '00, Thomas Alex Stephenson Jan 2002

Collision-Induced Electronic Energy Transfer From V=0 Of The E(0+G) Ion-Pair State In I2: Collisions With He And Ar, Christopher J. Fecko , '98, Miriam Arak Freedman , '00, Thomas Alex Stephenson

Chemistry & Biochemistry Faculty Works

The electronic energy transfer pathways that occur following collisions between I-2 in the E ion-pair electronic state (v = 0, J = 55) and He and Ar atoms have been determined. The nearby D, D', and beta ion-pair states are populated, but with relative branching ratios that vary with the rare gas collision partner. In He/I-2 collisions, the D state is preferentially populated, while Ar/I-2 collisions preferentially populate the beta electronic state. Bimolecular rate constants and effective hard sphere collision cross sections have been determined for each channel; the cross sections range from 7.0 +/- 1.0 Angstrom(2) for populating the …


Essays On Cooperative Behaviour And Collective Action., Anindya Bhattacharya Dr. Jan 2002

Essays On Cooperative Behaviour And Collective Action., Anindya Bhattacharya Dr.

Doctoral Theses

This dissertation explores some issues concerning the behaviour of coalitions of individuals in a game theoretic set-up and also studies one aspect of a society facing collective action of the masses. The common feature of the issues explored in the dissertation is that it investigates the properties of stable social states. Chapter 2 introduces a notion of a social state that is unlikely to be displaced by any coalition of agents endowed with a certain notion of rationality and a certain degree of farsightedness and explores the properties of such states. Chapter 3 is also concerned with coalitionally stable social …


Ecotones: The Heartbeat Of Huxley, 2002, Winter, Issue 01, Laurel Eddy, Huxley College Of The Environment, Western Washington University Jan 2002

Ecotones: The Heartbeat Of Huxley, 2002, Winter, Issue 01, Laurel Eddy, Huxley College Of The Environment, Western Washington University

Historical Collection of Huxley Newsletters

No abstract provided.