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2009

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Articles 1351 - 1380 of 7616

Full-Text Articles in Physical Sciences and Mathematics

Policy Overview And Options For Maximizing The Role Of Policy In Geothermal Electricity Development, Elizabeth Doris, Claire Kreycik, Katherine Young Sep 2009

Policy Overview And Options For Maximizing The Role Of Policy In Geothermal Electricity Development, Elizabeth Doris, Claire Kreycik, Katherine Young

Publications (E)

Geothermal electricity production1 capacity has grown over time because of multiple factors, including its renewable, baseload, and domestic attributes; volatile and high prices for competing technologies; and policy intervention. Overarching federal policies, namely the Public Utilities Regulatory Policies Act (PURPA),2 provided certainty to project investors in the 1980s, leading to a boom in geothermal development. In addition to market expansion through PURPA, research and development policies provided an investment of public dollars toward developing technologies and reducing costs over time to increase the market competitiveness of geothermal electricity. Together, these efforts are cited as the primary policy drivers for the …


Describing The Economic Impact Of The Oil And Gas Industry In Arkansas, Katherine A. Deck, Viktoria Riiman Sep 2009

Describing The Economic Impact Of The Oil And Gas Industry In Arkansas, Katherine A. Deck, Viktoria Riiman

Publications and Presentations

The Arkansas oil and natural gas industries are increasingly important to the state’s economic vitality. As global demand for energy increases, domestic production is put into the spotlight. This study describes the economic impact of the oil and gas industries in Arkansas, focusing on the sector’s economic output, employment, and tax revenues.


Update Sequence Stability In Graph Dynamical Systems, Matthew Macauley, Henning S. Mortveit Sep 2009

Update Sequence Stability In Graph Dynamical Systems, Matthew Macauley, Henning S. Mortveit

Publications

In this article, we study finite dynamical systems defined over graphs, where the functions are applied asynchronously. Our goal is to quantify and understand stability of the dynamics with respect to the update sequence, and to relate this to structural properties of the graph. We introduce and analyze three different notions of update sequence stability, each capturing different aspects of the dynamics. When compared to each other, these stability concepts yield vastly different conclusions regarding the relationship between stability and graph structure, painting a more complete picture of update sequence stability.


Stochastic Particle Acceleration In The Lobes Of Giant Radio Galaxies, Stephen O'Sullivan, Brian Reville, Andrew Taylor Sep 2009

Stochastic Particle Acceleration In The Lobes Of Giant Radio Galaxies, Stephen O'Sullivan, Brian Reville, Andrew Taylor

Articles

We investigate the acceleration of particles by Alfv ́en waves via the second-order Fermi process in the lobes of giant radio galaxies. Such sites are candidates for the accelerators of ultra-high-energy cosmic rays (UHECR). We focus on the nearby Fanaroff–Riley type I radio galaxy Centaurus A. This is motivated by the coincidence of its position with the arrival direction of several of the highest energy Auger events. The conditions necessary for consistency with the acceleration time-scales predicted by quasi-linear theory are reviewed. Test particle calculations are performed in fields which guarantee electric fields with no component parallel to the local …


Accelerating Sift On Parallel Architectures, Amy Apon, Seth Warn, Wesley Emeneker, Jackson Cothren Sep 2009

Accelerating Sift On Parallel Architectures, Amy Apon, Seth Warn, Wesley Emeneker, Jackson Cothren

Publications

SIFT is a widely-used algorithm that extracts features from images; using it to extract information from hundreds of terabytes of aerial and satellite photographs requires parallelization in order to be feasible. We explore accelerating an existing serial SIFT implementation with OpenMP parallelization and GPU execution.


A Guide To Shoreline Management Planning For Virginia’S Coastal Localities, Donna A. Milligan, C. Scott Hardaway Jr. Sep 2009

A Guide To Shoreline Management Planning For Virginia’S Coastal Localities, Donna A. Milligan, C. Scott Hardaway Jr.

Reports

Short pamphlet describing methods for managing and making recommendations for shorelines.


Using Population Synthesis Of Massive Stars To Study The Interstellar Medium Near Ob Associations, R. Voss, R. Diehl, Dieter H. Hartmann, M. Cerviño, J. S. Vink, G. Meynet, M. Limongi, A. Chieffi Sep 2009

Using Population Synthesis Of Massive Stars To Study The Interstellar Medium Near Ob Associations, R. Voss, R. Diehl, Dieter H. Hartmann, M. Cerviño, J. S. Vink, G. Meynet, M. Limongi, A. Chieffi

Publications

Aims. We study the massive stars in OB associations and their surrounding interstellar medium environment, using a population synthesis code. Methods. We developed a new population synthesis code for groups of massive stars, where we model the emission of different forms of energy and matter from the stars of the association. In particular, the ejection of the two radioactive isotopes 26Al and 60Fe is followed, as well as the emission of hydrogen ionizing photons, and the kinetic energy of the stellar winds and supernova explosions. We investigate various alternative astrophysical inputs and the resulting output sensitivities, especially effects due to …


Effects Of High-Flux Neutron Beams On He-3 Cells Polarized In Situ With Spin-Exchange Optical Pumping, E. Babcock, S. Boag, M. Becker, W. C. Chen, T. E. Chupp, T. R. Gentile, Gordon L. Jones, A. K. Petukhov, T. Soldner, T. G. Walker Sep 2009

Effects Of High-Flux Neutron Beams On He-3 Cells Polarized In Situ With Spin-Exchange Optical Pumping, E. Babcock, S. Boag, M. Becker, W. C. Chen, T. E. Chupp, T. R. Gentile, Gordon L. Jones, A. K. Petukhov, T. Soldner, T. G. Walker

Articles

Polarized He-3 produced by spin-exchange optical pumping (SEOP) has potential as a neutron spin filter for polarization and polarization analysis in many neutron-scattering and neutron particle physics applications. The advantage of the SEOP method is its suitability for providing continuous stable polarization over the course of long experiments. However, we have discovered that exposure to high neutron flux leads to additional strong relaxation mechanisms in the optically polarized alkali-metal vapor used to polarize the He-3. At a neutron flux density of 4.7 x 10(9) cm(-2) s(-1), the alkali-metal relaxation rate increased from 100 to 1000 s(-1) leading to reduced alkali-metal …


Extended Defects In The Potts-Percolation Model Of A Solid: Renormalization Group And Monte Carlo Analysis, H. T. Diep, Miron Kaufman Sep 2009

Extended Defects In The Potts-Percolation Model Of A Solid: Renormalization Group And Monte Carlo Analysis, H. T. Diep, Miron Kaufman

Physics Faculty Publications

We extend the model of a 2d solid to include a line of defects. Neighboring atoms on the defect line are connected by springs of different strength and different cohesive energy with respect to the rest of the system. Using the Migdal-Kadanoff renormalization group we show that the elastic energy is an irrelevant field at the bulk critical point. For zero elastic energy this model reduces to the Potts model. By using Monte Carlo simulations of the three- and four-state Potts model on a square lattice with a line of defects, we confirm the renormalization-group prediction that for a defect …


Assessment Of Mixing In Passive Microchannels With Fractal Surface Patterning, Petru S. Fodor, M. Itomlenskis, Miron Kaufman Sep 2009

Assessment Of Mixing In Passive Microchannels With Fractal Surface Patterning, Petru S. Fodor, M. Itomlenskis, Miron Kaufman

Physics Faculty Publications

We explore numerically the feasibility of enhancing the mixing capability of microchannels by employing the Weierstrass fractal function to generate a pattern of V-shaped ridges on the channel floor. Motivated by experimental limitations such as the finite resolution (similar to 10 mu m) associated with rapid prototyping through soft lithography techniques, we study the influence on the quality of mixing of having finite width ridges. The mixing capability of the designs studied is evaluated using an entropic measure and the designs are optimized with respect to: the distances between the ridges and the position range of their tip along the …


Casimir Chemistry, D. P. Sheehan Sep 2009

Casimir Chemistry, D. P. Sheehan

Physics and Biophysics: Faculty Scholarship

It is shown that, at the nanoscale, the Casimir effect can be used to mechanically tune critical aspects of chemical reaction e.g., energies, equilibrium constants, activation energies, transition states, reaction rates by varying the spacing and composition of reaction vessel boundaries. This suggests new modalities for catalysts, nanoscale chemical manufacturing, chemical-mechanical engines, and biochemical processes in organisms.


A Latent Model For Visual Disambiguation Of Keyword-Based Image Search, Kong-Wah Wan, Ah-Hwee Tan, Joo-Hwee Lim, Liang-Tien Chia, Sujoy Roy Sep 2009

A Latent Model For Visual Disambiguation Of Keyword-Based Image Search, Kong-Wah Wan, Ah-Hwee Tan, Joo-Hwee Lim, Liang-Tien Chia, Sujoy Roy

Research Collection School Of Computing and Information Systems

The problem of polysemy in keyword-based image search arises mainly from the inherent ambiguity in user queries. We propose a latent model based approach that resolves user search ambiguity by allowing sense specific diversity in search results. Given a query keyword and the images retrieved by issuing the query to an image search engine, we first learn a latent visual sense model of these polysemous images. Next, we use Wikipedia to disambiguate the word sense of the original query, and issue these Wiki-senses as new queries to retrieve sense specific images. A sense-specific image classifier is then learnt by combining …


Detecting Automotive Exhaust Gas Based On Fuzzy Inference System, Li. Shujin, Ming Bai, Quan Wang, Bo Chen, Xiaobing Zhao, Ting Yang, Zhaoxia Wang Sep 2009

Detecting Automotive Exhaust Gas Based On Fuzzy Inference System, Li. Shujin, Ming Bai, Quan Wang, Bo Chen, Xiaobing Zhao, Ting Yang, Zhaoxia Wang

Research Collection School Of Computing and Information Systems

This paper proposes a method of detecting automotive exhaust gas based on fuzzy logic inference after analyzing the principle of the infrared automobile exhaust gas analyzer and the influence of the environmental temperature on analyzer. This paper analyses the measurement error caused by environmental temperature, and then makes a non-linear error correction of temperature for the infrared sensor using fuzzy inference. The results of simulation have clearly demonstrated that the proposed fuzzy compensation scheme is better than the non-fuzzy method.


Ua35/1 Doers & Deeds Vol. 7, No. 12, Wku Provost Sep 2009

Ua35/1 Doers & Deeds Vol. 7, No. 12, Wku Provost

WKU Archives Records

Newsletter created by the WKU Provost & Vice President of Academic Affairs to highlight the activities of faculty, staff and alumni.


Batch Mode Active Learning With Applications To Text Categorization And Image Retrieval, Steven C. H. Hoi, Rong Jin, Michael R. Lyu Sep 2009

Batch Mode Active Learning With Applications To Text Categorization And Image Retrieval, Steven C. H. Hoi, Rong Jin, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Most machine learning tasks in data classification and information retrieval require manually labeled data examples in the training stage. The goal of active learning is to select the most informative examples for manual labeling in these learning tasks. Most of the previous studies in active learning have focused on selecting a single unlabeled example in each iteration. This could be inefficient, since the classification model has to be retrained for every acquired labeled example. It is also inappropriate for the setup of information retrieval tasks where the user's relevance feedback is often provided for the top K retrieved items. In …


Communication-Efficient Classification In P2p Networks, Hock Hee Ang, Vivekanand Gopalkrishnan, Wee Keong Ng, Steven C. H. Hoi Sep 2009

Communication-Efficient Classification In P2p Networks, Hock Hee Ang, Vivekanand Gopalkrishnan, Wee Keong Ng, Steven C. H. Hoi

Research Collection School Of Computing and Information Systems

Distributed classification aims to learn with accuracy comparable to that of centralized approaches but at far lesser communication and computation costs. By nature, P2P networks provide an excellent environment for performing a distributed classification task due to the high availability of shared resources, such as bandwidth, storage space, and rich computational power. However, learning in P2P networks is faced with many challenging issues; viz., scalability, peer dynamism, asynchronism and fault-tolerance. In this paper, we address these challenges by presenting CEMPaR—a communication-efficient framework based on cascading SVMs that exploits the characteristics of DHT-based lookup protocols. CEMPaR is designed to be robust …


Theoretical Studies Of 2,3 -Sigmatropic Rearrangements Of Allylic Selenoxides And Selenimides, Craig A. Bayse, Sonia Antony Sep 2009

Theoretical Studies Of 2,3 -Sigmatropic Rearrangements Of Allylic Selenoxides And Selenimides, Craig A. Bayse, Sonia Antony

Chemistry & Biochemistry Faculty Publications

Density-functional theory is used to model the endo and exo transition states for [2,3]-sigmatropic rearrangement of allylic aryl-selenoxides and -selenimides. The endo transition state is generally preferred for selenoxides if there is no substitution at the 2 position of the allyl group. Based upon the relative energies of the endo and exo transition states, enantioselectivity of rearrangements is expected to be greatest for molecules with substitutions at the 1- or (E)-3- position of the allyl group. Ortho substitution of a nitro group on the ancillary selenoxide phenyl ring reduces the activation barriers, increases the difference between the endo and exo …


Scientific Programming: The Promises Of Typed, Pure, And Lazy Functional Programming: Part Ii, Konstantin Läufer, George K. Thiruvathukal Sep 2009

Scientific Programming: The Promises Of Typed, Pure, And Lazy Functional Programming: Part Ii, Konstantin Läufer, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

This second installment picks up where Konrad Hinsen's article "The Promises of Functional Programming" from the July/August 2009 issue left off, covering static type inference and lazy evaluation in functional programming languages.


Water Quality Conditions And Restoration Of Submerged Aquatic Vegetation (Sav) In The Tidal Freshwater James River, 2008, Ken Moore, Betty Berry Neikirk, Erin C. Shields, David Parrish Sep 2009

Water Quality Conditions And Restoration Of Submerged Aquatic Vegetation (Sav) In The Tidal Freshwater James River, 2008, Ken Moore, Betty Berry Neikirk, Erin C. Shields, David Parrish

Reports

In 2008, wild celery (Vallisneria americana), water stargrass (Heteranthera dubia) and hydrilla (Hydrilla verticilata) shoots were transplanted into shallow water sites in the Hopewell region of the tidal James River and sampled for survivorship and growth throughout the SA V growing season. Water quality sampling was conducted at bi-weekly intervals throughout the year for water column nutrients, chlorophyll a, suspended solids, water transparency and other chemical and physical constituents important for SA V growth. Continuous water quality sampling was also conducted along the James River from the mouth of the Chickahominy River to the upstream limits of tidal water at …


Contributing Efforts In The Search For Neutrinoless Double Beta Decay, Laura Christine Sparks Sep 2009

Contributing Efforts In The Search For Neutrinoless Double Beta Decay, Laura Christine Sparks

Physics

Cryogenic Underground Observatory for Rare Events (CUORE) will be part of the next generation of detectors used to search for neutrinoless double beta decay (0νββ). Located in Assergi, Italy at the Gran Sasso National Laboratory (LNGS), CUORE will be a large cryogenic bolometer composed of 988 tellurium dioxide (TeO2) detectors with a total mass of 750 kg, and will search for 0νββ in 130Te. As the experiment will monitor the extremely rare event of 0νββ, all factors contributing to background need to be minimized to effectively increase the sensitivity. I assisted the LNGS researchers over the summer of 2008 by …


Security And Network Analysis Using Simulation, Victor A. Clincy Sep 2009

Security And Network Analysis Using Simulation, Victor A. Clincy

Faculty Articles

ITGuru is a powerful simulation environment developed by OpNET Corporation. ITGuru is unique because of its ability to model the entire networking domain, including its routers, switches, protocols, servers, and the individual applications they support. ITGuru improves network researchers' and instructors' ability to identify and solve problems throughout the network. The OpNET Corporation provides a FREE academic copy of their simulation environment to universities for both teaching and research.


Interface Slippage Study Between Polyamide 12 And Ethylene Butene Copolymer Melt In Capillary Extrusion, Jinhai Yang, James L. White Sep 2009

Interface Slippage Study Between Polyamide 12 And Ethylene Butene Copolymer Melt In Capillary Extrusion, Jinhai Yang, James L. White

Faculty Publications

Extrusion of a polyamide 12 (PA12) material through a capillary die coated with an ethylene butene copolymer (EBM) was studied. The EBM coated die significantly increased the flow rates of the PA12 melt compared to a clean die at the same extrusion pressure. Introducing a maleic anhydride grafted ethylene-octene copolymer (EOM-g-MAH) into the EBM suppressed the effect. This behavior seems only explained by significant interface slippage between PA12 and EBM melts, which could be eliminated by introducing covalent chemical bonds across the interface. A mathematical analysis was carried out to calculate the interface slippage. The shear stress where slippage began …


Factors Influencing Perennial Pasture Adoption In The Medium Rainfall Zone Of The South West Natural Resource Management Region Of Western Australia, Ned Crossley, Stephen Tunbridge, Kathi Mcdonald Sep 2009

Factors Influencing Perennial Pasture Adoption In The Medium Rainfall Zone Of The South West Natural Resource Management Region Of Western Australia, Ned Crossley, Stephen Tunbridge, Kathi Mcdonald

Resource management technical reports

No abstract provided.


Measurement Of D ± And D 0 Production In Deep Inelastic Scattering Using A Lifetime Tag At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, F. Cindolo, M. Corradi, G. Iacobucci, A. Margotti, R. Nania, A. Polini, S. Antonelli, M. Basile, M. Bindi, L. Cifarelli, A. Contin, S. De Pasquale, G. Sartorelli, A. Zichichi, D. Bartsch, I. Brock, H. Hartmann Sep 2009

Measurement Of D ± And D 0 Production In Deep Inelastic Scattering Using A Lifetime Tag At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, F. Cindolo, M. Corradi, G. Iacobucci, A. Margotti, R. Nania, A. Polini, S. Antonelli, M. Basile, M. Bindi, L. Cifarelli, A. Contin, S. De Pasquale, G. Sartorelli, A. Zichichi, D. Bartsch, I. Brock, H. Hartmann

Faculty Publications

The production of D ±- and D 0-mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of 133.6 pb-1. The measurements cover the kinematic range 52<1000 >GeV2, 0.02


Experimental And Theoretical Investigation Of Molecular Field Effects By Polarization-Resolved Resonant Inelastic X-Ray Scattering, Stephane Carniato, Renaud Guillemin, Wayne C. Stolte, Loic Journel, Richard Taieb, Dennis W. Lindle, Marc Simon Sep 2009

Experimental And Theoretical Investigation Of Molecular Field Effects By Polarization-Resolved Resonant Inelastic X-Ray Scattering, Stephane Carniato, Renaud Guillemin, Wayne C. Stolte, Loic Journel, Richard Taieb, Dennis W. Lindle, Marc Simon

Chemistry and Biochemistry Faculty Research

We present a combined theoretical and experimental study of molecular field effects on molecular core levels. Polarization-dependent resonant inelastic x-ray scattering is observed experimentally after resonant K-shell excitation of CF3Cl and HCl. We explain the linear dichroism observed in spin-orbit level intensities as due to molecular field effects, including singlet-triplet exchange, and interpret this behavior in terms of population differences in the 2px,y,z inner-shell orbitals. We investigate theoretically the different factors that can affect the electronic populations and the dynamical R dependence of the spin-orbit ratio. Finally, the results obtained are used to interpret the L-shell …


Hierarchical Self-Healing Key Distribution For Heterogeneous Wireless Sensor Networks, Yanjiang Yang, Jianying Zhou, Robert H. Deng, Feng Bao Sep 2009

Hierarchical Self-Healing Key Distribution For Heterogeneous Wireless Sensor Networks, Yanjiang Yang, Jianying Zhou, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Self-healing group key distribution aims to achieve robust key distribution over lossy channels in wireless sensor networks (WSNs). However, all existing self-healing group key distribution schemes in the literature consider homogenous WSNs which are known to be unscalable. Heterogeneous WSNs have better scalability and performance than homogenous ones. We are thus motivated to study hierarchial self-healing group key distribution, tailored to the heterogeneous WSN architecture. In particular, we revisit and adapt Dutta et al.’s model to the setting of hierarchical self-healing group key distribution, and propose a concrete scheme that achieves computational security and high efficiency.


Visible Reverse K-Nearest Neighbor Query Processing In Spatial Databases, Yunjun Gao, Baihua Zheng, Gencai Chen, Wang-Chien Lee, Ken C. K. Lee, Qing Li Sep 2009

Visible Reverse K-Nearest Neighbor Query Processing In Spatial Databases, Yunjun Gao, Baihua Zheng, Gencai Chen, Wang-Chien Lee, Ken C. K. Lee, Qing Li

Research Collection School Of Computing and Information Systems

Reverse nearest neighbor (RNN) queries have a broad application base such as decision support, profile-based marketing, resource allocation, etc. Previous work on RNN search does not take obstacles into consideration. In the real world, however, there are many physical obstacles (e.g., buildings) and their presence may affect the visibility between objects. In this paper, we introduce a novel variant of RNN queries, namely, visible reverse nearest neighbor (VRNN) search, which considers the impact of obstacles on the visibility of objects. Given a data set P, an obstacle set O, and a query point q in a 2D space, a VRNN …


Self-Authentication Of Audio Signals By Chirp Coding, Jonathan Blackledge, Eugene Coyle Sep 2009

Self-Authentication Of Audio Signals By Chirp Coding, Jonathan Blackledge, Eugene Coyle

Conference papers

This paper discusses a new approach to ‘watermarking’ digital signals using linear frequency modulated or ‘chirp’ coding. The principles underlying this approach are based on the use of a matched filter to provide a reconstruction of a chirped code that is uniquely robust in the case of signals with very low signal-to-noise ratios. Chirp coding for authenticating data is generic in the sense that it can be used for a range of data types and applications (the authentication of speech and audio signals, for example). The theoretical and computational aspects of the matched filter and the properties of a chirp …


Multi-View Ear Recognition Based On Moving Least Square Pose Interpolation, Heng Liu, David Zhang, Zhiyuan Zhang Sep 2009

Multi-View Ear Recognition Based On Moving Least Square Pose Interpolation, Heng Liu, David Zhang, Zhiyuan Zhang

Research Collection School Of Computing and Information Systems

Based on moving least square, a multi-view ear pose interpolation and corresponding recognition approach is proposed. This work firstly analyzes the shape characteristics of actual trace caused by ear pose varying in feature space. Then according to training samples pose projection, we manage to recover the complete multi-view ear pose manifold by using moving least square pose interpolation. The constructed multi-view ear pose manifolds can be easily utilized to recognize ear images captured under different views based on finding the minimal projection distance to the manifolds. The experimental results and some comparisons show the new method is superior to manifold …


Efficient Conditional Proxy Re-Encryption With Chosen-Ciphertext Security, Jian Weng, Yanjiang Yang, Qiang Tang, Robert H. Deng Sep 2009

Efficient Conditional Proxy Re-Encryption With Chosen-Ciphertext Security, Jian Weng, Yanjiang Yang, Qiang Tang, Robert H. Deng

Research Collection School Of Computing and Information Systems

Recently, a variant of proxy re-encryption, named conditional proxy re-encryption (C-PRE), has been introduced. Compared with traditional proxy re-encryption, C-PRE enables the delegator to implement fine-grained delegation of decryption rights, and thus is more useful in many applications. In this paper, based on a careful observation on the existing definitions and security notions for C-PRE, we re-formalize more rigorous definition and security notions for C-PRE. We further propose a more efficient C-PRE scheme, and prove its chosen-ciphertext security under the decisional bilinear Diffie-Hellman (DBDH) assumption in the random oracle model. In addition, we point out that a recent C-PRE scheme …