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2006

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Articles 631 - 660 of 5872

Full-Text Articles in Physical Sciences and Mathematics

Security In Pervasive Computing: Current Status And Open Issues, Munirul Haque, Sheikh Iqbal Ahamed Nov 2006

Security In Pervasive Computing: Current Status And Open Issues, Munirul Haque, Sheikh Iqbal Ahamed

Mathematics, Statistics and Computer Science Faculty Research and Publications

Million of wireless device users are ever on the move, becoming more dependent on their PDAs, smart phones, and other handheld devices. With the advancement of pervasive computing, new and unique capabilities are available to aid mobile societies. The wireless nature of these devices has fostered a new era of mobility. Thousands of pervasive devices are able to arbitrarily join and leave a network, creating a nomadic environment known as a pervasive ad hoc network. However, mobile devices have vulnerabilities, and some are proving to be challenging. Security in pervasive computing is the most critical challenge. Security is needed to …


A Case Study On Grid Performance Modeling, Amy Apon, Baochuan Lu, Larry Dowdy, Frank Robinson, Doug Hoffman, Denny Brewer Nov 2006

A Case Study On Grid Performance Modeling, Amy Apon, Baochuan Lu, Larry Dowdy, Frank Robinson, Doug Hoffman, Denny Brewer

Publications

The purpose of this case study is to develop a performance model for an enterprise grid for performance management and capacity planning1. The target environment includes grid applications such as health-care and financial services where the data is located primarily within the resources of a worldwide corporation. The approach is to build a discrete event simulation model for a representative work-flow grid. Five work-flow classes, found using a customized k-means clustering algorithm characterize the workload of the grid. Analyzing the gap between the simulation and measurement data validates the model. The case study demonstrates that the simulation model can be …


State Of Yorktown Beach 2006, Donna A. Milligan, C. Scott Hardaway Jr., Kevin O'Brien, Christine A. Wilcox Nov 2006

State Of Yorktown Beach 2006, Donna A. Milligan, C. Scott Hardaway Jr., Kevin O'Brien, Christine A. Wilcox

Reports

The Yorktown Public Beach is located on the south side of the York River at Yorktown,Virginia (Figure 1). Recently, it has undergone dramatic transformation with the construction of floating piers, upscale restaurants and shops, parking garage, and additional shore management structures. The main recreational beach is now about 1,600 feet in length. A new section of beach and breakwaters is located upstream of the main recreational shore; this project area is 1,500 ft long which includes property owned by the Waterman’s Museum. The middle section of the shoreline downriver of the Route 17 Coleman Bridge, where the floating piers are …


Clinical Data Entry & Protocol Tracking System, Neeta Pophali Nov 2006

Clinical Data Entry & Protocol Tracking System, Neeta Pophali

Regis University Student Publications (comprehensive collection)

CLINICAL DATA ENTRY & PROTOCOL TRACKING SYSTEM (CDEPT) is a software framework designed to provide the tools necessary to rapidly develop web based data entry and data management systems for clinical trails and medical research studies. A software framework defines a model, approach, procedures and tools for creating new protocols for clinical studies. As a framework this software is able to gain efficiency by providing standard approaches and tools for commonly needed capabilities such as construction of data entry routines, validation of data, audit trails and monitoring the completeness and timeliness of data collection. However, as a framework this software …


Mantle Transition Zone Discontinuities Beneath The Baikal Rift And Adjacent Areas, Kelly H. Liu, Stephen S. Gao Nov 2006

Mantle Transition Zone Discontinuities Beneath The Baikal Rift And Adjacent Areas, Kelly H. Liu, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Like most other major continental rifts, the Baikal rift zone (BRZ) in Siberia is presumably underlain by a hot and partially molten mantle, which has a reduced seismic velocity relative to surrounding areas. Recent seismic tomography studies, however, gave conflicting results about the depth extent and even the existence of the low-velocity anomaly beneath the BRZ, suggesting that additional constraints are needed. Here we present results from stacking of about 1700 radial P-to-S receiver functions from a single long-running seismic station, TLY, located at the SW tip of Lake Baikal. A clear uplift of the 410 km discontinuity (d410) with …


Robust Controllability In Temporal Constraint Networks Under Uncertainty, Hoong Chuin Lau, Jia Li, Roland H. C. Yap Nov 2006

Robust Controllability In Temporal Constraint Networks Under Uncertainty, Hoong Chuin Lau, Jia Li, Roland H. C. Yap

Research Collection School Of Computing and Information Systems

Temporal constraint networks are embedded in many planning and scheduling problems. In dynamic problems, a fundamental challenge is to decide whether such a network can be executed as uncertainty is revealed over time. Very little work in this domain has been done in the probabilistic context. In this paper, we propose a Temporal Constraint Network (TCN) model where durations of uncertain activities are represented by random variables. We wish to know whether such a network is robust controllable, i.e. can be executed dynamically within a given failure probability, and if so, how one might find a feasible schedule as the …


Dcma: A Label-Switching Mac For Efficient Packet Forwarding In Multi-Hop Wireless Networks, Arup Acharya, Sachin Ganu, Archan Misra Nov 2006

Dcma: A Label-Switching Mac For Efficient Packet Forwarding In Multi-Hop Wireless Networks, Arup Acharya, Sachin Ganu, Archan Misra

Research Collection School Of Computing and Information Systems

This paper addresses the problem of efficient packet forwarding in a multihop, wireless "mesh" network. We present an efficient interface contained forwarding (ICF) architecture for a "wireless router," i.e., a forwarding node with a single wireless network interface card (NIC) in a multihop wireless network that allows a packet to be forwarded entirely within the NIC of the forwarding node without requiring per-packet intervention by the node's CPU. To effectively forward packets in a pipelined fashion without incurring the 802.11-related overheads of multiple independent channel accesses, we specify a slightly modified version of the 802.11 MAC, called data driven cut-through …


Recent Developments In Understanding Two-Dimensional Turbulence And The Nastrom-Gage Spectrum, Eleftherios Gkioulekas, Ka Kit Tung Nov 2006

Recent Developments In Understanding Two-Dimensional Turbulence And The Nastrom-Gage Spectrum, Eleftherios Gkioulekas, Ka Kit Tung

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Two-dimensional turbulence appears to be a more formidable problem than three-dimensional turbulence despite the numerical advantage of working with one less dimension. In the present paper we review recent numerical investigations of the phenomenology of two-dimensional turbulence as well as recent theoretical breakthroughs by various leading researchers. We also review efforts to reconcile the observed energy spectrum of the atmosphere (the spectrum) with the predictions of two-dimensional turbulence and quasigeostrophic turbulence.


A Model For Anticipatory Event Detection, Qi He, Kuiyu Chang, Ee Peng Lim Nov 2006

A Model For Anticipatory Event Detection, Qi He, Kuiyu Chang, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Event detection is a very important area of research that discovers new events reported in a stream of text documents. Previous research in event detection has largely focused on finding the first story and tracking the events of a specific topic. A topic is simply a set of related events defined by user supplied keywords with no associated semantics and little domain knowledge. We therefore introduce the Anticipatory Event Detection (AED) problem: given some user preferred event transition in a topic, detect the occurence of the transition for the stream of news covering the topic. We confine the events to …


Low-Latency Broadcast In Multirate Wireless Mesh Networks, Chun Tung Chou, Archan Misra, Junaid Qadir Nov 2006

Low-Latency Broadcast In Multirate Wireless Mesh Networks, Chun Tung Chou, Archan Misra, Junaid Qadir

Research Collection School Of Computing and Information Systems

In a multirate wireless network, a node can dynamically adjust its link transmission rate by switching between different modulation schemes. In the current IEEE802.11a/b/g standards, this rate adjustment is defined for unicast traffic only. In this paper, we consider a wireless mesh network (WMN), where a node can dynamically adjust its link-layer multicast rates to its neighbors, and address the problem of realizing low-latency network-wide broadcast in such a mesh. We first show that the multirate broadcast problem is significantly different from the single-rate case. We will then present an algorithm for achieving low-latency broadcast in a multirate mesh which …


New Paradigm Of Inference Control With Trusted Computing, Yanjiang Yang, Yingjiu Li, Robert H. Deng Nov 2006

New Paradigm Of Inference Control With Trusted Computing, Yanjiang Yang, Yingjiu Li, Robert H. Deng

Research Collection School Of Computing and Information Systems

The database server is a crucial bottleneck in traditional inference control architecture, as it enforces highly computation-intensive auditing for all users who query the protected database. As a result, most auditing methods, though rigorously studied, can never be implemented in practice for protecting largescale real-world database systems. To shift this paradigm, we propose a new inference control architecture that will entrust inference control to each users platform, provided that the platform is equipped with trusted computing technology. The trusted computing technology is designed to attest the state of a users platform to the database server, so as to assure the …


Category 5 Hurricane Evacuation Analysis Of The Rio Grande Valley Of Texas: Maximum Flow Problem, Bart Webb Nov 2006

Category 5 Hurricane Evacuation Analysis Of The Rio Grande Valley Of Texas: Maximum Flow Problem, Bart Webb

Theses and Dissertations - UTB/UTPA

The author evaluated the capability of evacuating the Rio Grande Valley of Texas (Hidalgo, Willacy, and Cameron Counties) in the event of a Category 5 hurricane.

This analysis determined the duration of an evacuation required for this region in the event of a Category 5 hurricane using the evacuation maps from the State of Texas, including areas where contraflow is proposed. The Ford and Fulkerson methodology was the basis of the Maximum Flow problem for the following Category 5 hurricane scenarios: 1) Evacuation constrained only by road capacity, 2) Evacuation constrained by a Department of Homeland Security checkpoint at Falfurrias, …


Water Resources And Geologic Field Trip In York And Seward Counties, Nebraska, Michael J. Jess, Mark Burbach Nov 2006

Water Resources And Geologic Field Trip In York And Seward Counties, Nebraska, Michael J. Jess, Mark Burbach

Conservation and Survey Division

No abstract provided.


Idaho Pend Oreille River Model: Model Development And Calibration, Robert Leslie Annear, Chris Berger, Scott A. Wells Nov 2006

Idaho Pend Oreille River Model: Model Development And Calibration, Robert Leslie Annear, Chris Berger, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The objectives of this project were to:

• Develop a hydrodynamic and temperature model of Pend Oreille River using CE-QUAL-W2 Version 3.2

• Calibrate the CE-QUAL-W2 model to field data collected during 2004 and 2005 using the following water quality variables:

  • flow, water surface elevation, and velocity
  • temperature o dissolved oxygen
  • nutrients (NO3-N+NO2-N, NH4-N, PO4-P)
  • algae – chlorophyll a
  • BOD5 and dissolved organic matter and particulate organic matter compartments (both labile and refractory) for the organic matter cycling with algae
  • periphyton

The model chosen for development was CE-QUAL-W2 Version 3.2 (Cole and Wells, 2004). This is a two-dimensional unsteady hydrodynamic …


True Blue: Blue-Emitting Aluminum(Iii) Quinolinolate Complexes, Cesar Perez-Bolivar, Victor A. Montes, Pavel Anzenbacher Jr. Nov 2006

True Blue: Blue-Emitting Aluminum(Iii) Quinolinolate Complexes, Cesar Perez-Bolivar, Victor A. Montes, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

Blue-emitting heteroleptic aluminum(III) bis(2-methyl-8-quinolinolate) phenolate complexes were synthesized. A tunable, blue-to-green emission is achieved by attaching electron-withdrawing modulators to the emisssive quinaldinate ligand. The electronic nature of modulator substituents attached to the position of the highest HOMO (highest occupied molecular orbital) density is used to modulate ligand HOMO levels to achieve effective emission tuning to obtain blue-emitting materials. Optical and electrochemical properties of the resulting complexes were investigated and compared to the results of density functional theory (DFT/B3LYP/6-31G*) studies. The resulting materials may find application as organic light-emitting device materials.


Climate Change And Adaptation In South West Western Australia, State Greenhouse Action Committee, Luke Morgan Nov 2006

Climate Change And Adaptation In South West Western Australia, State Greenhouse Action Committee, Luke Morgan

Bulletins 4000 -

Phase One of Action 5.5, State Greenhouse Strateg.

A report to the Western Australian Government and Australian Greenhouse Office

Community, industry and government views on past and future climate change for South West Western Australia


Traditional Medicine And Traditional Music In Madagascar, Nat Quansah Oct 2006

Traditional Medicine And Traditional Music In Madagascar, Nat Quansah

Nat Quansah

No abstract provided.


Bridging The Time And Frequency Domains Enables Raman Spectroscopy With Femtosecond Pulses, Sean Kern, Diana Urbanek, Sukhendu Nath, Mark Berg Oct 2006

Bridging The Time And Frequency Domains Enables Raman Spectroscopy With Femtosecond Pulses, Sean Kern, Diana Urbanek, Sukhendu Nath, Mark Berg

Sean J. Kern

No abstract provided.


A Content-Driven Reputation System For The Wikipedia, B. Thomas Adler, Luca De Alfaro Oct 2006

A Content-Driven Reputation System For The Wikipedia, B. Thomas Adler, Luca De Alfaro

Luca de Alfaro

On-line forums for the collaborative creation of bodies of information are a phenomenon of rising importance; the Wikipedia is one of the best-known examples. The open nature of such forums could benefit from a notion of reputation for its authors. Author reputation could be used to flag new contributions from low-reputation authors, and it could be used to allow only authors with good reputation to contribute to controversial or critical pages. A reputation system for the Wikipedia would also provide an incentive to give high-quality contributions.

We present in this paper a novel type of content-driven reputation system for Wikipedia …


Injection, Trapping, And Acceleration Of Electrons In A Three-Dimensional Nonlinear Laser Wakefield, Serguei Y. Kalmykov, Leonid M. Gorbunov, Patrick Mora, Gennady Shvets Oct 2006

Injection, Trapping, And Acceleration Of Electrons In A Three-Dimensional Nonlinear Laser Wakefield, Serguei Y. Kalmykov, Leonid M. Gorbunov, Patrick Mora, Gennady Shvets

Serge Youri Kalmykov

It is demonstrated that the accelerating and focusing phases of the nonlinear three-dimensional axisymmetric laser wake can almost entirely overlap starting from a certain distance behind the laser pulse in homogeneous plasma. Such field structure results from the curvature of phase fronts due to the radially inhomogeneous relativistic shift of plasma frequency. Consequently, the number of trapped low-energy electrons can be much greater than that predicted by the linear wake theory. This effect is favorable for quasi-monoenergetic acceleration of a considerable charge (several hundreds of pC) to about 1 GeV per electron in the plasma wakefield driven by an ultrashort …


Snapshots Of Laser Wakefields, Nicholas H. Matlis, Steven A. Reed, Stepan S. Bulanov, Vladimir Chvykov, Galina Kalintchenko, Takeshi Matsuoka, Pascal Rousseau, Victor Yanovsky, Anatoly Maksimchuk, Serguei Y. Kalmykov, Gennady Shvets, Michael C. Downer Oct 2006

Snapshots Of Laser Wakefields, Nicholas H. Matlis, Steven A. Reed, Stepan S. Bulanov, Vladimir Chvykov, Galina Kalintchenko, Takeshi Matsuoka, Pascal Rousseau, Victor Yanovsky, Anatoly Maksimchuk, Serguei Y. Kalmykov, Gennady Shvets, Michael C. Downer

Serge Youri Kalmykov

Tabletop plasma accelerators can now produce GeV-range electron beams and femtosecond X-ray pulses, providing compact radiation sources for medicine, nuclear engineering, materials science and high-energy physics. In these accelerators, electrons surf on electric fields exceeding 100 GeV m^{−1}, which is more than 1,000 times stronger than achievable in conventional accelerators. These fields are generated within plasma structures (such as Langmuir waves or electron density ‘bubbles’) propagating near light speed behind laser or charged-particle driving pulses. Here, we demonstrate single-shot visualization of laser-wakefield accelerator structures for the first time. Our ‘snapshots’ capture the evolution of multiple wake periods, detect structure variations …


A Variable Length Linear Array For Smart Antenna Systems Using Partial Optimization, W. Raad, Ian S. Burnett Oct 2006

A Variable Length Linear Array For Smart Antenna Systems Using Partial Optimization, W. Raad, Ian S. Burnett

Faculty of Informatics - Papers (Archive)

Adaptive arrays have been used extensively in wireless communications applications to reduce interference between desired users and interfering signals. Significant research has been directed at the uniform linear array (ULA), however, generally a fixed array length is used. In a mobile environment this has the disadvantage of producing a fixed beamwidth due to the fixed array lengths. The variable linear array (VLA) algorithm is a proposed algorithm that allows the beamwidth to be varied by activating and deactivating elements depending on the interferers present. This approach uses the LMS algorithm for adaptation, in an embedded system this could prove costly. …


Neuro-Fuzzy Admission Control In Cellular Networks, Raad Raad, Ibrahim Raad Oct 2006

Neuro-Fuzzy Admission Control In Cellular Networks, Raad Raad, Ibrahim Raad

Faculty of Informatics - Papers (Archive)

In this paper, a methodology is presented for designing an adaptive fuzzy logic controller based on neural networks. The neuro-fuzzy controller is first trained using data from an approximate analytical model of a cellular network then the controller is fine tuned and adapted to the unique cell dwell time and call holding time distributions of a particular cell in the network. Different cell dwell time distributions are considered for training the neuro-fuzzy controller. A neuro-fuzzy method that only relies on a limited amount of measured data for training purposes is also presented.


A New Spreading Matrix For Block Spread Ofdm, Ibrahim S. Raad, Xiaojing Huang, Raad Raad Oct 2006

A New Spreading Matrix For Block Spread Ofdm, Ibrahim S. Raad, Xiaojing Huang, Raad Raad

Faculty of Informatics - Papers (Archive)

This paper presents a new spreading matrix for block spread OFDM (BSOFDM) to improve the performance of the system by increasing the correlation between the symbols. This is achieved by rotating the modulation scheme used at the transmission, say QPSK, into a higher order modulation scheme, for example 16QAM. By this the correlation between the transmitted symbols is increased. The advantage of this new spreading matrix over more traditional spreading matrices is its flexibility in achieving different higher order modulation schemes during transmission depending on the angle alpha. This is compared to other spreading matrices in frequency selective channel environment.


Analysis Of Large Scale Image Data Using Out-Of-Core Techniques, Chandrashekara H. Raju, Thomas Wischgoll Oct 2006

Analysis Of Large Scale Image Data Using Out-Of-Core Techniques, Chandrashekara H. Raju, Thomas Wischgoll

Computer Science and Engineering Faculty Publications

No abstract provided.


High Temperature Heat Exchanger Project: Quarterly Progress Report July 1, 2006 Through September 30, 2006, Anthony Hechanova Oct 2006

High Temperature Heat Exchanger Project: Quarterly Progress Report July 1, 2006 Through September 30, 2006, Anthony Hechanova

Publications (NSTD)

Hydrodynamics and thermal numerical modeling coupled with sulfur trioxide decomposition for the one channel geometry with three different channel configurations were performed. The results obtained from the numerical modeling were compared with the baseline design under the same boundary and operation conditions. The case with diamond shaped channels has the highest percentage of sulfuric acid decomposition. The baseline channel geometry has the lowest pressure drop compared with other cases.


Ordering Tendencies In The Binary Alloys Of Rh, Pd, Ir, And Pt: Density Functional Calculations, Gus L. W. Hart, Brian Kolb, Stefan Müller, David B. Botts Oct 2006

Ordering Tendencies In The Binary Alloys Of Rh, Pd, Ir, And Pt: Density Functional Calculations, Gus L. W. Hart, Brian Kolb, Stefan Müller, David B. Botts

Faculty Publications

The binary alloys of Rh, Pd, Ir, and Pt are important because of their high catalytic potential. We report in this paper that the Rh1-xIrx and Rh1-xPtx systems, long thought to phase separate at low temperatures, actually exhibit miscibility over the entire concentration and temperature range. We find low critical ordering temperatures, indicating that long-range order is unlikely to be observed experimentally. These results are compared with previous theoretical predications for the other binary alloys of Rh, Pd, Ir, and Pt and with calculations performed here on the Pt1-xIrx and Pd1-xIrx systems. We discuss these results and investigate the mechanisms …


Pedagogical Possibilities For The N-Puzzle Problem, Zdravko Markov, Ingrid Russell, Todd W. Neller, Neli Zlatareva Oct 2006

Pedagogical Possibilities For The N-Puzzle Problem, Zdravko Markov, Ingrid Russell, Todd W. Neller, Neli Zlatareva

Computer Science Faculty Publications

In this paper we present work on a project funded by the National Science Foundation with a goal of unifying the Artificial Intelligence (AI) course around the theme of machine learning. Our work involves the development and testing of an adaptable framework for the presentation of core AI topics that emphasizes the relationship between AI and computer science. Several hands-on laboratory projects that can be closely integrated into an introductory AI course have been developed. We present an overview of one of the projects and describe the associated curricular materials that have been developed. The project uses machine learning as …


Radial Velocity Observations Of The Extended Lunar Sodium Tail, E. J. Mierkiewicz, M. Line, F. L. Roesler, R. J. Oliversen Oct 2006

Radial Velocity Observations Of The Extended Lunar Sodium Tail, E. J. Mierkiewicz, M. Line, F. L. Roesler, R. J. Oliversen

Physical Sciences - Daytona Beach

We report the first velocity resolved sodium 5889.950 Å line profile observations of the lunar sodium tail observed in the anti-lunar direction near new Moon. These observations were made on 29 March 2006, 27 April 2006 and 28 April 2006 from Pine Bluff (WI) observatory with a double etalon Fabry-Perot spectrometer at a resolving power of ∼80,000. The observations were made within 2–14 hours from new Moon, pointing near the anti-lunar point. The average observed radial velocity of the lunar sodium tail in the vicinity of the anti-lunar point for the three nights reported was 12.4 km s−1 (from …


Some Problems In Additive Number Theory., Gyan Prakash Dr. Oct 2006

Some Problems In Additive Number Theory., Gyan Prakash Dr.

Doctoral Theses

No abstract provided.