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2002

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Articles 1981 - 2010 of 3435

Full-Text Articles in Physical Sciences and Mathematics

Extensible Information Brokers, Jianguo Lu, John Mylopoulos Jan 2002

Extensible Information Brokers, Jianguo Lu, John Mylopoulos

Computer Science Publications

The number and size of information services available on the internet has been growing exponentially over the past few years. This growth has created an urgent need for information agents that act as brokers in the sense that they can autonomously search, gather, and integrate information on behalf of a user. To remain useful, such brokers will have to evolve throughout their lifetime to keep up with evolving and ever-changing information services. This paper proposes a framework named XIB (eXtensible Information Brokers) for building and evolving information brokers.

The XIB takes as input a description of required information services and …


Ventures Into Capturing Effort In Programming, Barbara Bernal-Thomas, Briana B. Morrison Jan 2002

Ventures Into Capturing Effort In Programming, Barbara Bernal-Thomas, Briana B. Morrison

Computer Science Faculty Proceedings & Presentations

The quest for teaching a method of data collection in programming experiences was marked with successes and failures. We believe that software development curricula must provide students with knowledge and experience related to the practice of data collection, which will measure the effort put into a software project. By recording their past effort in software projects, students can more accurately estimate the amount of effort and time required to complete a future software project. Students can also learn the amount of effort required to develop “correct” software and begin to estimate the amount of time required, per software phase, to …


Determining The Locus For Photocarrier Recombination In Dye-Sensitized Solar Cells, Kai Zhu, Eric A. Schiff, N. G. Park, J. Van De Lagemaat, A. J. Frank Jan 2002

Determining The Locus For Photocarrier Recombination In Dye-Sensitized Solar Cells, Kai Zhu, Eric A. Schiff, N. G. Park, J. Van De Lagemaat, A. J. Frank

Physics - All Scholarship

We present intensity-modulated photocurrent and infrared transmittance measurements on dye-sensitized solar cells based on a mesoporous titania (TiO2) matrix immersed in an iodine-based electrolyte. Under short-circuit conditions, we show that an elementary analysis accurately relates the two measurements. Under open-circuit conditions, infrared transmittance, and photovoltage measurements yield information on the characteristic depth at which electrons recombine with ions (the ‘‘locus of recombination’’). For one particular series of samples recombination occurred near the substrate supporting the titania film, as opposed to homogeneously throughout the film.


Infrared Charge-Modulation Spectroscopy Of Defects In Phosphorus Doped Amorphous Silicon, Kai Zhu, Eric A. Schiff, G. Ganguly Jan 2002

Infrared Charge-Modulation Spectroscopy Of Defects In Phosphorus Doped Amorphous Silicon, Kai Zhu, Eric A. Schiff, G. Ganguly

Physics - All Scholarship

We present infrared charge-modulation absorption spectra on phosphorus-doped amorphous silicon (a-Si:H:P) with doping levels between 0.17% - 5%. At higher doping levels (1% - 5%) we find a sharp spectral line near 0.75 eV with a width of 0.1 eV. We attribute this line to the internal optical transitions of a complex incorporating four fold coordinated phosphorus and a dangling bond. This line is barely detectable in samples with lower doping levels (below 1%). In these samples a much broader line dominates the spectrum that we attribute to uncomplexed dopants. The relative strength of the two spectral features is in …


Thermionic Emission Model For Interface Effects On The Open-Circuit Voltage Of Amorphous Silicon Based Solar Cells, Eric A. Schiff Jan 2002

Thermionic Emission Model For Interface Effects On The Open-Circuit Voltage Of Amorphous Silicon Based Solar Cells, Eric A. Schiff

Physics - All Scholarship

We present computer modeling for effects of the p/i interface upon the open-circuit voltage VOC in amorphous silicon based pin solar cells. We show that the modeling is consistent with measurements on the intensitydependence for the interface effect, and we present an interpretation for the modeling based on thermionic emission of electrons over the electrostatic barrier at the p/i interface. We present additional modeling of the relation of VOC with the intrinsic layer bandgap EG. The experimental correlation for optimized cells is VOC = (EG/e)-0.79. The correlation is simply explained if VOC in these cells is determined by the intrinsic …


Photocarrier Drift Mobility Measurements And Electron Localization In Nanoporous Silicon, P. N. Rao, Eric A. Schiff, L. Tsybeskov, P. Fauchet Jan 2002

Photocarrier Drift Mobility Measurements And Electron Localization In Nanoporous Silicon, P. N. Rao, Eric A. Schiff, L. Tsybeskov, P. Fauchet

Physics - All Scholarship

We report photocarrier time-of-flight measurements in diode structures made of highly porous crystalline silicon. The corresponding electron and hole drift mobilities are very small ð<104 cm2=V sÞ compared to homogeneous crystalline silicon. The mobilities are dispersive (i.e., having a power-law decay with time or length-scale), but are only weakly temperature-dependent. The dispersion parameter lies in the range 0.55–0.65 for both electrons and holes. We conclude that the drift mobilities are limited by the nanoporous geometry, and not by disorder-induced localized states acting as traps. This conclusion is surprising in the context of luminescence models based on radiative recombination of localized excitons.


International Telephone Calls: Global And Regional Patterns, Risa Palm Jan 2002

International Telephone Calls: Global And Regional Patterns, Risa Palm

Geosciences Faculty Publications

This study examines patterns in international telephone communications, documenting a close relationship between international call volume aggregated by nation and indicators of global connectivity including volume of international trade, tourism and migration. In addition, the analysis documents the existence of a set of national “communities” of callers. The clear orientation of large portions of the world to former colonial powers (e.g., West Africa and North Africa to France), and the separation of the Muslim Middle East and the Chinese-speaking nations of East and Southeast Asia from other calling communities suggest the importance of continuing historic and cultural influences on information …


The Internet And Home Purchase, Risa Palm Jan 2002

The Internet And Home Purchase, Risa Palm

Geosciences Faculty Publications

In the pre-internet era, information was a key determinant of the geographic nature of intra- urban moves. Information was a far more limited commodity, and therefore subject to management and even manipulation. Information brokers, particularly real estate agents, could order and limit the kinds of information to which prospective buyers gained access, with the potential of strongly biasing search space. In the past few years, a vastly enriched information source on housing vacancies has become available through real estate industry-sponsored sites on the internet. This rich information source has the potential to influence spatial patterns and processes in the search …


Sheaf Cohomology Of Conscious Entity, Goro Kato Jan 2002

Sheaf Cohomology Of Conscious Entity, Goro Kato

Mathematics

Awareness of a conscious entity can exist without elements; therefore, the general notion of an object of a category is employed. One of the characterization of understanding is: for a given local infonnation (awareness) there exists a global information whose restriction is the given information. For such mental activities, category and sheaf theories are employed to formulate consciousness. We will show that the cohomology (more general precohomology) object, a subquotient object, better represents the essence of a conscious entity than an object itself. We will also give a definition of an observation to fonnulate the collapse of the wave and …


Category Theory And Consciousness, Goro Kato, Daniele C. Struppa Jan 2002

Category Theory And Consciousness, Goro Kato, Daniele C. Struppa

Mathematics

No abstract provided.


Orbifold Homeomorphism And Diffeomorphism Groups, Joseph E. Borzellino, Victor Brunsden Jan 2002

Orbifold Homeomorphism And Diffeomorphism Groups, Joseph E. Borzellino, Victor Brunsden

Mathematics

In this paper we outline results on orbifold diffeomorphism groups that were presented at the International Conference on Infinite Dimensional Lie Groups in Geometry and Representation Theory at Howard University, Washington DC on August 17-21, 2000. Specifically, we define the notion of reduced and unreduced orbifold diffeomorphism groups. For the reduced orbifold diffeomorphism group we state and sketch the proof of the following recognition result: Let O1 and O2 be two compact, locally smooth orbifolds. Fix r ≥ 0. Suppose that Φ : Diffr (O1) → Diffr (O2) is a group isomorphism. Then Φ is induced by redred a (topological) …


Levy-Like Continuity Theorems For Convergence In Distribution, Theodore P. Hill, Ulrich Krengel Jan 2002

Levy-Like Continuity Theorems For Convergence In Distribution, Theodore P. Hill, Ulrich Krengel

Research Scholars in Residence

Levy’s classical continuity theorem states that if the pointwise limit of a sequence of characteristic functions exists, then the limit function itself is a characteristic function if and only if the limit function satisfies a single universal limit condition (in his case, the limit at zero is one), in which case the underlying measures converge weakly to the probability measure represented by the limit function. It is the purpose of this article to give a number of direct analogs of L´evy’s theorem for other probability-representing functions including moment sequences, maximal moment sequences, mean-residual-life functions, Hardy-Littlewood maximal functions, and failure-rate functions. …


Human-Robot Interaction: Final Report For Darpa/Nsf Study On Human-Robot Interaction, Erika Rogers, Robin R. Murphy Jan 2002

Human-Robot Interaction: Final Report For Darpa/Nsf Study On Human-Robot Interaction, Erika Rogers, Robin R. Murphy

Computer Science and Software Engineering

No abstract provided.


Calorimetric Study Of Block-Copolymers Of Poly(N-Butyl Acrylate) And Gradient Poly(N-Butyl Acrylate-Co-Methyl Methacrylate), A I. Buzin, M Pyda, P Costanzo, K Matyjaszewski, B Wunderlich Jan 2002

Calorimetric Study Of Block-Copolymers Of Poly(N-Butyl Acrylate) And Gradient Poly(N-Butyl Acrylate-Co-Methyl Methacrylate), A I. Buzin, M Pyda, P Costanzo, K Matyjaszewski, B Wunderlich

Chemistry and Biochemistry

The nanophase separation in diblock and triblock copolymers consisting of immiscible poly(n-butyl acrylate) (block A) and gradient copolymers of methyl methacrylate (MMA) and n-butyl acrylate (n BA) (block M/A) were investigated by means of their heat capacity, Cp, as a function of the composition of the blocks M/A and temperature. In all copolymers studied, both blocks are represented by their Cp and glass transition temperature, Tg, as well as the broadening of the transition-temperature range. The low-temperature transition of the blocks A is always close to that of the …


Quantitative Ground-Truthing Of Habitat Characteristics Using Video Mosaic Images, Randy G. Cutter Jr., Yuri Rzhanov, Larry A. Mayer Jan 2002

Quantitative Ground-Truthing Of Habitat Characteristics Using Video Mosaic Images, Randy G. Cutter Jr., Yuri Rzhanov, Larry A. Mayer

Center for Coastal and Ocean Mapping

No abstract provided.


Hilbert Spaces Induced By Toeplitz Covariance Kernels, Mihaela Teodora Matache, Valentin Matache Jan 2002

Hilbert Spaces Induced By Toeplitz Covariance Kernels, Mihaela Teodora Matache, Valentin Matache

Faculty Books and Monographs

This is a book chapter that appeared in Stochastic Theory and Control by Bozenna Pasik-Duncan (ed.).

This volume contains almost all of the papers that were presented at the Workshop on Stochastic Theory and Control that was held at the Univ- sity of Kansas, 18–20 October 2001. This three-day event gathered a group of leading scholars in the ?eld of stochastic theory and control to discuss leading-edge topics of stochastic control, which include risk sensitive control, adaptive control, mathematics of ?nance, estimation, identi?cation, optimal control, nonlinear ?ltering, stochastic di?erential equations, stochastic p- tial di?erential equations, and stochastic theory and its …


Xml-Based Modeling And Simulation: Web Service Technologies And Their Synergy With Simulation, Senthilanand Chandrasekaran, Gregory S. Silver, John A. Miller, Jorge Cardoso, Amit P. Sheth Jan 2002

Xml-Based Modeling And Simulation: Web Service Technologies And Their Synergy With Simulation, Senthilanand Chandrasekaran, Gregory S. Silver, John A. Miller, Jorge Cardoso, Amit P. Sheth

Kno.e.sis Publications

The World Wide Web has had an huge influence on the computing field in general as well as simulation in particular (e.g., Web-based simulation). A new wave of development based upon XML has started. Two of the most interesting aspects of this development are the Semantic Web and Web services. This paper examines the synergy between Web service technology and simulation. In one direction, Web service processes can be simulated for the purpose of correcting/improving the design. In the other direction, simulation models/components can be built out of Web services. Work on seamlessly using simulation as a part of Web …


An Analytical Model For Virtual Topology Reconfiguration In Optical Networks And A Case Study, Xi Yang, Byrav Ramamurthy Jan 2002

An Analytical Model For Virtual Topology Reconfiguration In Optical Networks And A Case Study, Xi Yang, Byrav Ramamurthy

CSE Conference and Workshop Papers

An analytical model for Virtual Topology Reconfiguration (VTR) in optical networks is developed. It aims at the optical networks with a circuit-based data plane and an IPlike control plane. By identifying and analyzing the important factors impacting the network performance due to VTR operations on both planes, we can compare the benefits and penalties of different VTR algorithms and policies. The best VTR scenario can be adaptively chosen from a set of such algorithms and policies according to the real-time network situations. For this purpose, a cost model integrating all these factors is created to provide a comparison criterion independent …


Constraint Modeling And Reformulation In The Context Of Academic Task Assignment, Robert Glaubius, Berthe Y. Choueiry Jan 2002

Constraint Modeling And Reformulation In The Context Of Academic Task Assignment, Robert Glaubius, Berthe Y. Choueiry

CSE Conference and Workshop Papers

We discuss the modeling and reformulation of a resource allocation problem, the assignment of graduate teaching assistants (GTAs) to courses. Our research contributes the following:

• Formulation of the GTA assignment problem as a nonbinary CSP.

• Design of a new convention for consistency checking to deal with over-constrained problem.

• Definition of a new network-decomposable nonbinary confinement constraint.

• Evaluation of the reformulation of confinement and equality constraints on 3 real-world data sets.


Planetary Bioresources And Astroecology 1. Planetary Microcosm Bioassays Of Martian And Carbonaceous Chondrite Materials: Nutrients, Electrolyte Solutions, And Algal And Plant Responses, Michael Noah Mautner Jan 2002

Planetary Bioresources And Astroecology 1. Planetary Microcosm Bioassays Of Martian And Carbonaceous Chondrite Materials: Nutrients, Electrolyte Solutions, And Algal And Plant Responses, Michael Noah Mautner

Chemistry Publications

The biological fertilities of planetary materials can be assessed using microcosms based on materials in martian and carbonaceous chondrite meteorites. Their biological fertilities are rated based on soluble electrolyte nutrients, on the growth of mesophile and cold-tolerant algae, and of plant tissue cultures. The Murchison CM2 carbonaceous chondrite meteorite and DaG 476 martian shergottite contain high levels of water-extractable Ca, Mg, and SO4–S. The martian meteorites DaG 476 and EETA 79001 also contain high levels of extractable nutrients NO3–N (0.013–0.017 g kg1) and PO4–P (0.019–0.046 g kg1). The yields of most of the water-extractable …


Automated Ontology Learning For A Semantic Web, Christopher N. Hammack, Qingfeng Lin, Hai Huang, Stephen Scott, Sharad C. Seth Jan 2002

Automated Ontology Learning For A Semantic Web, Christopher N. Hammack, Qingfeng Lin, Hai Huang, Stephen Scott, Sharad C. Seth

CSE Technical Reports

By expressing web page content in a format that machines can understand, the semantic web provides huge possibilities for the Internet and for machine reasoning. Unfortunately, there is a considerable distance between the present-day World Wide Web and the semantic web of the future. The process of annotating the Web to make it semantic web-ready is quite long and not without resistance. In this paper one mechanism for semanticizing the Web is presented. This system is known as AutoSHOE, and it is capable of categorizing pages according to one of the present HTML semantic representations (Simple HTML Ontology Extensions) by …


Centralized Vs. Distributed Connection Management Schemes Under Different Traffic Patterns In Wavelength-Convertible Optical Networks, Lu Shen, Byrav Ramamurthy Jan 2002

Centralized Vs. Distributed Connection Management Schemes Under Different Traffic Patterns In Wavelength-Convertible Optical Networks, Lu Shen, Byrav Ramamurthy

CSE Conference and Workshop Papers

Centralized and Distributed methods are two connection management schemes in wavelength convertible optical networks. In the earlier work, the centralized scheme is said to have lower network blocking probability than the distributed one. Hence, much of the previous work in connection management has focused on the comparison of different algorithms in only distributed scheme or in only centralized scheme. However, we believe that the network blocking probability of these two connection management schemes depends, to a great extent, on the network traffic patterns and reservation times. Our simulation results reveal that the performance improvement (in terms of blocking probability) of …


Specification Of Jecp/Sp: Stereographic Projection With An Application For Specimen Orientation Adjustment Using Tem Holders, Xingzhong Li Jan 2002

Specification Of Jecp/Sp: Stereographic Projection With An Application For Specimen Orientation Adjustment Using Tem Holders, Xingzhong Li

Nebraska Center for Materials and Nanoscience: Faculty Publications

1. Purpose of the program 2. Graphic user interface and program design 3. Crystallographic principle and implementation 4. System requirement 5. Installation and user instruction 6. How to contact the author 7. References

1. Purpose of the program JECP/SP is a computer program in Java Electron Crystallography Package. JECP is developed for quantitative electron diffraction and image processing, the package is designed and written by Dr. XingZhong Li. JECP/SP provides the all necessary functions of stereographic projection for regular application and furthermore it can be used to minimized the difficulties encountered when tilting highly beam-sensitive, or small-grain-size specimens with known …


Atmospheric Turbulence Conditions Leading To Focused And Folded Sonic Boom Wave Fronts, Andrew A. Piacsek Jan 2002

Atmospheric Turbulence Conditions Leading To Focused And Folded Sonic Boom Wave Fronts, Andrew A. Piacsek

All Faculty Scholarship for the College of the Sciences

The propagation and subsequent distortion of sonic booms with rippled wave fronts are investigated theoretically using a nonlinear time-domain finite-difference scheme. This work seeks to validate the rippled wave front approach as a method for explaining the significant effects of turbulence on sonic booms [A. S. Pierce and D. J. Maglieri, J. Acoust. Soc. Am. 51, 702–721 (1971)]. A very simple description of turbulence is employed in which velocity perturbations within a shallow layer of the atmosphere form strings of vortices characterized by their size and speed. Passage of a steady-state plane shock front through such a vortex layer …


Integrating Environmental Education With Family And Consumer Science Education, Trina Lin Stangland Jan 2002

Integrating Environmental Education With Family And Consumer Science Education, Trina Lin Stangland

All Graduate Projects

This project provides lessons and activities for the integration of environmental education throughout the family and consumer science curriculum. The project reflects the most current standards including the Washington State Environmental Education Guidelines and Essential Academic Learning Requirements, as well as the Family and Consumer Science National Standards. Many appropriate areas of implementation were discovered in the review of literature. The lessons and activities presented in this project are informed by the literature and are, subsequently, diverse and desirable for family and consumer science education. Each lesson or activity includes detailed information on which standards they reflect as well as …


Environmental Awareness Curriculum For First Grade, Dianna Lynn Whitley Jan 2002

Environmental Awareness Curriculum For First Grade, Dianna Lynn Whitley

All Graduate Projects

An environmental curriculum was created to increase student's awareness about their environment. The purpose was to provide students with knowledge and skills to participate in environmental issues. Three sub-topics were researched, Waste Management, Water Pollution and Water Conservation. Lessons were developed for all three areas to implement in a first grade classroom. The lessons are diverse and will meet the needs of all learning styles.


Precursory Transient Slip During The 2001 MW = 8.4 Peru Earthquake Sequence From Continuous Gps, Timothy I. Melbourne, Frank H. Webb Jan 2002

Precursory Transient Slip During The 2001 MW = 8.4 Peru Earthquake Sequence From Continuous Gps, Timothy I. Melbourne, Frank H. Webb

Faculty Scholarship for the Cascadia Hazards Institute

Two-hour position estimates from a continuous GPS station located at Arequipa, Peru, document precursory deformation beginning 18 hours prior to an Mw = 7.6 aftershock of the June 23rd 2001 Mw = 8.4 earthquake. This preseismic signal appears on the north and east components as a slow displacement with an amplitude twice that of the subsequent coseismic. Analysis of three years of 18-hour rate measurement shows this signal to be unprecedented and beyond four standard deviations from the mean rate. The best fitting centroid is directionally consistent with slow slip along the plate interface and suggests the preseismic …


Dive Tourism: Evaluating Service Quality, Martin O'Neill, Martin Maccarthy, Paul Abdullah Jan 2002

Dive Tourism: Evaluating Service Quality, Martin O'Neill, Martin Maccarthy, Paul Abdullah

Hospitality Review

Through the application of importance- performance analysis (/PA), the author investigated the conceptualization and measurement of service quality for tour operators in the scuba diving industry Findings from a study of consumer perceptions of service quality as they relate to a dive tour operator in Western Australia revealed the core service quality dimensions hat need to be improved for the operator and demonstrated the values and relative simplicity of the importance-performance analyses for dive tour operators generally


Tr-2002005: Towards A Theory Of Social Software, Rohit Parikh Jan 2002

Tr-2002005: Towards A Theory Of Social Software, Rohit Parikh

Computer Science Technical Reports

No abstract provided.


Tr-2002006: States Of Knowledge, Rohit Parikh Jan 2002

Tr-2002006: States Of Knowledge, Rohit Parikh

Computer Science Technical Reports

No abstract provided.