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Articles 2401 - 2430 of 3436

Full-Text Articles in Physical Sciences and Mathematics

On The Steering Of Sound Energy Through A Supercritical Plate By A Near-Field Transducer Array, Brian E. Anderson, Stephen A. Hambric, Jack W. Hughes May 2008

On The Steering Of Sound Energy Through A Supercritical Plate By A Near-Field Transducer Array, Brian E. Anderson, Stephen A. Hambric, Jack W. Hughes

Faculty Publications

The ability to direct sound energy through the flexural vibrations of a submerged plate at various angles of incidence using a near-field transducer array is investigated. An alumina bar is placed in front of a one-dimensional, eight-element transducer array, between the array and the water. Operating in a receive mode, data were taken as a function of angle of incidence and compared to data taken without the presence of the alumina bar. The array was also operated in transmit mode and results were compared to corresponding receive mode data, showing that reciprocity holds. Results show that in fact sound energy …


Automating Mini-Ontology Generation From Canonical Tables, Stephen G. Lynn Apr 2008

Automating Mini-Ontology Generation From Canonical Tables, Stephen G. Lynn

Theses and Dissertations

In this thesis work we develop and test MOGO (a Mini-Ontology GeneratOr.) MOGO automates the generation of mini-ontologies from canonicalized tables of data. This will help anyone trying to organize large amounts of existing data into a more searchable and accessible form. By using a number of different heuristic rules for selecting, enhancing, and modifying ontology elements, MOGO allows users to automatically, semi-automatically, or manually generate conceptual mini-ontologies from canonicalized tables of data. Ideally, MOGO operates fully automatically while allowing users to intervene to direct and correct when necessary so that they can always satisfactorily complete the translation of canonicalized …


Contribution Of Recharge Along Regional Flow Paths To Discharge At Ash Meadows, Nevada, Michelle Bushman Apr 2008

Contribution Of Recharge Along Regional Flow Paths To Discharge At Ash Meadows, Nevada, Michelle Bushman

Theses and Dissertations

Springs in the Ash Meadows, Nevada wetland area are discharging groundwater at a high volume that cannot be sustained by local, present-day precipitation and associated recharge. Previous groundwater flow models for this region have required groundwater to flow through complex geology for long distances (160km) through fractures that, in the current stress field, should be closed in many instances in the presumed flow direction. This thesis examines several possible flow paths and evaluates each flow path using chemical and isotopic signatures in the water, as well as geologic and geophysical constraints, and determines that flow from beneath the Yucca Mountain …


Geology Of The Phil Pico Mountain Quadrangle, Daggett County, Utah, And Sweetwater County, Wyoming, Alvin D. Anderson Apr 2008

Geology Of The Phil Pico Mountain Quadrangle, Daggett County, Utah, And Sweetwater County, Wyoming, Alvin D. Anderson

Theses and Dissertations

Geologic mapping in the Phil Pico Mountain quadrangle and analysis of the Carter Oil Company Carson Peak Unit 1 well have provided additional constraints on the erosional and uplift history of this section of the north flank of the Uinta Mountains. Phil Pico Mountain is largely composed of the conglomeratic facies of the early Eocene Wasatch and middle to late Eocene Bridger Formations. These formations are separated by the Henrys Fork fault which has thrust Wasatch Formation next to Bridger Formation. The Wasatch Formation is clearly synorogenic and contains an unroofing succession from the adjacent Uinta Mountains. On Phil Pico …


The Optimal Weighting Of Pre-Election Polling Data, Gregory K. Johnson Apr 2008

The Optimal Weighting Of Pre-Election Polling Data, Gregory K. Johnson

Theses and Dissertations

Pre-election polls are used to test the political landscape and predict election results. The relative weights for the state-level data from the 2006 U.S. senatorial races are considered based on the date on which the polls were conducted. Long- and short-memory weight functions are developed to specify the relative value of historical polling data. An optimal weight function is estimated by minimizing the discrepancy function between estimates from weighted polls and the election outcomes.


Metallicity And Effective Temperature Of The Secondary Or Rs Ophicuhi, R. L. Pearson Iii, Ya. V. Pavlenko, A. Evans, T. Kerr, L. Yakovina, C. E. Woodward, D. Lynch, R. Rudy, R. W. Russell Apr 2008

Metallicity And Effective Temperature Of The Secondary Or Rs Ophicuhi, R. L. Pearson Iii, Ya. V. Pavlenko, A. Evans, T. Kerr, L. Yakovina, C. E. Woodward, D. Lynch, R. Rudy, R. W. Russell

Faculty Publications

Context. The recurrent nova RS Ophiuchi undergoes nova eruptions every 10-20 years as a result of thermonuclear runaway on the surface of a white dwarf close to the Chandrasekhar limit. Both the progress of the eruption and its aftermath depend on the (poorly known) composition of the red giant in the RS Oph system. Aims. Our aim is to understand better the effect of the giant secondary on the recurrent nova eruption. Methods. Synthetic spectra were computed for a grid of M-giant model atmospheres having a range of effective temperatures 3200 < Teff < 4400 K, gravities 0 < log g < 1 and abundances -4 < [Fe/H] < 0.5, and fit to infrared spectra of RS Oph as it returned to quiescence after its 2006 eruption. We have modelled the infrared spectrum in the range 1.4-2.5µm to determine metallicity and effective temperature of the red giant. Results. We find Teff= 4100 ±100 K, log g = 0.0 ±0.5, [Fe/H] = 0.0 ±0.5, [C/H] = -0.8 ±0.2, [N/H] = +0.6 ±0.3 in the atmosphere of the secondary, and demonstrate that inclusion of some dust "veiling" in the spectra cannot improve our fits.


Improving Spreadsheets For Complex Problems, Brian C. Whitmer Apr 2008

Improving Spreadsheets For Complex Problems, Brian C. Whitmer

Theses and Dissertations

Spreadsheets are one of the most frequently used applications. They are used because they are easy to understand and values can be updated easily. However, many people try to use spreadsheets for problems beyond their intended scope and end up with errors and miscalculations. We present a new spreadsheet system which uses complex-values and equation code reuse to overcome the limitations of spreadsheets for complex problems. We also discuss the features necessary in order to make these enhancements useful and effective.


Generalized Constrained Interpolation, Jacob Porter Merrell Apr 2008

Generalized Constrained Interpolation, Jacob Porter Merrell

Theses and Dissertations

Interpolation is essential in digital image processing, especially magnification. Many different approaches to interpolation specific to magnification have been developed in an effort to overcome the shortcomings of bilinear and bicubic interpolation. One of these approaches, Constraint-Based Interpolation, produces an image that is free of jaggies and has less blurring than bilinear or bicubic interpolation. Although Constraint-Based Interpolation produces a visually pleasing image, there are user-chosen parameters that make the algorithm difficult to use. In this thesis we propose a method for automatic selection of those parameters and an extension of Constraint-Based Interpolation to other forms of image manipulation, such …


Increasing Dogma Scaling Through Clustering, Nathan Hyrum Ekstrom Apr 2008

Increasing Dogma Scaling Through Clustering, Nathan Hyrum Ekstrom

Theses and Dissertations

DOGMA is a distributed computing architecture developed at Brigham Young University. It makes use of idle computers to provide additional computing resources to applications, similar to Seti@home. DOGMA's ability to scale to large numbers of computers is hindered by its strict client-server architecture. Recent research with DOGMA has shown that introducing localized peer-to-peer downloading abilities enhances DOGMA's performance while reducing the amount of network and server usage. This thesis proposes to further extend the peer-to-peer abilities of DOGMA to include peering client server communication by creating dynamic clusters of clients. The client clusters aggregate their communication with only one client …


Skill Evaluation In Women's Volleyball, Lindsay W. Florence, Gilbert W. Fellingham, Pat R. Vehrs, Nina P. Mortensen Apr 2008

Skill Evaluation In Women's Volleyball, Lindsay W. Florence, Gilbert W. Fellingham, Pat R. Vehrs, Nina P. Mortensen

Faculty Publications

The Brigham Young University Women's Volleyball Team recorded and rated all skills (pass, set, attack, etc.) and recorded rally outcomes (point for BYU, rally continues, point for opponent) for the entire 2006 home volleyball season. Only sequences of events occurring on BYU's side of the net were considered. Events followed one of these general patterns: serve-outcome, pass-set-attack-outcome, or block-dig-set-attack-outcome. These sequences of events were assumed to be first-order Markov chains where the quality of each contact depended only on the quality of the previous contact but not explicitly on contacts further removed in the sequence. We represented these sequences in …


A Tool To Support Ontology Creation Based On Incremental Mini-Ontology Merging, Zonghui Lian Mar 2008

A Tool To Support Ontology Creation Based On Incremental Mini-Ontology Merging, Zonghui Lian

Theses and Dissertations

This thesis addresses the problem of tool support for semi-automatic ontology mapping and merging. Solving this problem contributes to ontology creation and evolution by relieving users from tedious and time-consuming work. This thesis shows that a tool can be built that will take a “mini-ontology” and a “growing ontology” as input and make it possible to produce manually, semi-automatically, or automatically an extended growing ontology as output. Characteristics of this tool include: (1) a graphical, interactive user interface with features that will allow users to map and merge ontologies, and (2) a framework supporting pluggable, semi-automatic, and automatic mapping and …


Comment On “Contact Conditions For The Charge In The Theory Of The Electrical Double Layer”, Douglas Henderson, L. B. Bhuiyan Mar 2008

Comment On “Contact Conditions For The Charge In The Theory Of The Electrical Double Layer”, Douglas Henderson, L. B. Bhuiyan

Faculty Publications

Exact results in any field, including statistical mechanics, are both aesthetically pleasing and very valuable in assessing theoretical approximations.


Improving Liquid State Machines Through Iterative Refinement Of The Reservoir, R David Norton Mar 2008

Improving Liquid State Machines Through Iterative Refinement Of The Reservoir, R David Norton

Theses and Dissertations

Liquid State Machines (LSMs) exploit the power of recurrent spiking neural networks (SNNs) without training the SNN. Instead, a reservoir, or liquid, is randomly created which acts as a filter for a readout function. We develop three methods for iteratively refining a randomly generated liquid to create a more effective one. First, we apply Hebbian learning to LSMs by building the liquid with spike-time dependant plasticity (STDP) synapses. Second, we create an eligibility based reinforcement learning algorithm for synaptic development. Third, we apply principles of Hebbian learning and reinforcement learning to create a new algorithm called separation driven synaptic modification …


Accelerating Corpus Annotation Through Active Learning, George Busby, Marc Carmen, James Carroll, Robbie Haertel, Deryle W. Lonsdale, Peter Mcclanahan, Eric K. Ringger, Kevin Seppi Mar 2008

Accelerating Corpus Annotation Through Active Learning, George Busby, Marc Carmen, James Carroll, Robbie Haertel, Deryle W. Lonsdale, Peter Mcclanahan, Eric K. Ringger, Kevin Seppi

Faculty Publications

PDF of Powerpoint Presentation on accelerating corpus annotation through active learning. This presentation was given at the Conference of the American Association for Corpus Linguistics in 2008.


Analysis Of Canonical Chinese Antonym Co-Occurrence, Eric K. Ringger, Guohui Liu, Shiping Liu, Xingfu Wang Mar 2008

Analysis Of Canonical Chinese Antonym Co-Occurrence, Eric K. Ringger, Guohui Liu, Shiping Liu, Xingfu Wang

Faculty Publications

PDF of Powerpoint Presentation on canonical Chinese antonym co-occurrence. This presentation was given at the Conference of the American Association for Corpus Linguistics in 2008.


Compiling And Annotating A Syriac Corpus, George Busby, James Carroll, Marc Carmen, Carl Griffin, Robbie Haertel, Kristian Heal, Joshua Heaton, Deryle W. Lonsdale, Peter Mcclanahan, Eric K. Ringger, Kevin Seppi, David Taylor Mar 2008

Compiling And Annotating A Syriac Corpus, George Busby, James Carroll, Marc Carmen, Carl Griffin, Robbie Haertel, Kristian Heal, Joshua Heaton, Deryle W. Lonsdale, Peter Mcclanahan, Eric K. Ringger, Kevin Seppi, David Taylor

Faculty Publications

PDF of Powerpoint Presentation on compiling and annotating a Syriac corpus. This presentation was given at the Conference of the American Association for Corpus Linguistics in 2008.


Approximations With Improving Error Bounds For Makespan Minimization In Batch Manufacturing, Whitney Samuel Weyerman Mar 2008

Approximations With Improving Error Bounds For Makespan Minimization In Batch Manufacturing, Whitney Samuel Weyerman

Theses and Dissertations

Multipurpose batch manufacturing systems allow a suite of job types to be processed with a fixed set of machines. These types of systems are commonly found in chemical processing, as well as in computer systems and the service industry. In this thesis we consider the problem of sequencing jobs entering the manufacturing system in order to minimize makespan, or total time to complete processing of the jobs. We formulate this problem as a dynamic programming problem and illustrate the computational difficulty of solving this problem. We give a method for simulation of the system by representing each machine in the …


Error Sensor Strategies For Active Noise Control And Active Acoustic Equalization In A Free Field, Ryan T. Chester Mar 2008

Error Sensor Strategies For Active Noise Control And Active Acoustic Equalization In A Free Field, Ryan T. Chester

Theses and Dissertations

Several measurements may be used as error signals to determine how to appropriately control a sound field. These include pressure, particle velocity, energy density and intensity. In this thesis, numerical models are used to show which signals perform best in is free-field active noise control (ANC) using error sensors located in the near field of the sound sources. The second is equalization in a free field and a semi-free field. Minimized energy density total power output (MEDToPO) plots are developed; these indicate the maximum achievable attenuation for a chosen error sensor as a function of location. A global listening area …


Extending Web Application Development To The User-Editable Space, Brian S. Goodrich Mar 2008

Extending Web Application Development To The User-Editable Space, Brian S. Goodrich

Theses and Dissertations

The growth of the web increased dramatically when users were provided with applications that let them use just their browser to post and edit content on the World Wide Web. Offering users the ability to use their browser to create their own web applications, instead of just posting text and images, would cause another Internet evolution. This thesis describes the EXPPO system (Extensible Page Productions and Operations), a web application development environment for both end-users and technical-users. EXPPO leverages the end-user's previous experience with internet browsers by using a page based development experience or a Page Oriented Architecture. Because applications …


Improving Performance Of The Filtered-X Least Mean Square Algorithm For Active Control Of Noise Contatining Multiple Quasi-Stationary Tones, Stephan P. Lovstedt Mar 2008

Improving Performance Of The Filtered-X Least Mean Square Algorithm For Active Control Of Noise Contatining Multiple Quasi-Stationary Tones, Stephan P. Lovstedt

Theses and Dissertations

The Filtered-X Least-Mean-Square (FXLMS) algorithm is widely used in active noise control due to its robustness, simplicity, and ability to be implemented in real time. In a feedforward implementation of the FXLMS algorithm, a reference signal that is highly correlated with the noise to be controlled is filtered with an estimate of the transfer function of the secondary path. The convergence characteristics of the FXLMS algorithm have been well studied. A convergence parameter is used to optimize the convergence of the algorithm. However, the optimal value for the convergence parameter is frequency dependent. Thus for noise containing multiple tones at …


Cpg: Closed Pseudonymous Groups, Reed S. Abbott Mar 2008

Cpg: Closed Pseudonymous Groups, Reed S. Abbott

Theses and Dissertations

Internet users generally feel their actions are anonymous, but this is often not the case. Users can be tracked and their actions logged for future analysis, which is not the desire of most users. Software and services exist which offer anonymity on the Internet when used correctly. Anonymity on the Internet is useful for many people including whistleblowers, dissidents, law enforcement, and the security conscious, but it can be abused. A user can act maliciously under the guise of anonymity without the fear of retribution. Thus, a level of administrative control over users is desirable, even in an anonymous system. …


Putting The Web Services Specifications To Rest, Dan R. Olsen Mar 2008

Putting The Web Services Specifications To Rest, Dan R. Olsen

Theses and Dissertations

Web services have become a useful and effective way of sharing information over the World Wide Web. SOAP has become a popular way of providing Web services and has been the focus of the Web Services specifications. The Web Services specifications provide additional capabilities to Web Services such as security and policy exchange. Another popular form of Web services includes light-weight Web or RESTful Web services over HTTP. These light-weight Web services are currently not addressed by the Web Services specifications. In order to provide the same capabilities to RESTful Web services, the Web Services specifications will be used to …


Skill Evaluation In Women's Volleyball, Lindsay Walker Florence Mar 2008

Skill Evaluation In Women's Volleyball, Lindsay Walker Florence

Theses and Dissertations

The Brigham Young University Women's Volleyball Team recorded and rated all skills (pass, set, attack, etc.) and recorded rally outcomes (point for BYU, rally continues, point for opponent) for the entire 2006 home volleyball season. Only sequences of events occurring on BYU's side of the net were considered. Events followed one of these general patterns: serve-outcome, pass-set-attack-outcome, or block-dig-set-attack-outcome. These sequences of events were assumed to be first-order Markov chains where the quality of each contact depended only explicitly on the quality of the previous contact but not on contacts further removed in the sequence. We represented these sequences in …


A Bittorrent Proxy, Robert Brent Larsen Mar 2008

A Bittorrent Proxy, Robert Brent Larsen

Theses and Dissertations

BitTorrent is a peer-to-peer protocol useful for distributing large files over the Internet. Many organizations use BitTorrent to distribute their software in order to reduce client download time and reduce the load on their servers. While there is a lot of legitimate content available via BitTorrent, some organizations ban BitTorrent usage due to concerns over copyright infringement and the amount of bandwidth that peers can consume. A BitTorrent proxy will allow organizations to control those risks and allow its members to use the BitTorrent protocol for approved uses. It will allow the organization to control the files that are downloaded …


Sub-Symbolic Re-Representation To Facilitate Learning Transfer, Dan A. Ventura Mar 2008

Sub-Symbolic Re-Representation To Facilitate Learning Transfer, Dan A. Ventura

Faculty Publications

We consider the issue of knowledge (re-)representation in the context of learning transfer and present a subsymbolic approach for effecting such transfer. Given a set of data, manifold learning is used to automatically organize the data into one or more representational transformations, which are then learned with a set of neural networks. The result is a set of neural filters that can be applied to new data as re-representation operators. Encouraging preliminary empirical results elucidate the approach and demonstrate its feasibility, suggesting possible implications for the broader field of creativity.


Clouds Search For Variability In Brown Dwarf Atmospheres: Infrared Spectroscopic Time Series Of L/T Transition Brown Dwarfs, D. Stephens, B. Goldman, M. C. Cushing, M. S. Marley, E. Artigau, K. S. Baliyan, V. J. S. Bejar, J. A. Caballero, N. Chanover, M. Connelley, R. Doyon, T. Forveille, S. Ganesh, C. R. Gelino, H. B. Hammel, J. Holtzman, S. Joshi, U. C. Joshi, S. K. Leggett, M. C. Liu Feb 2008

Clouds Search For Variability In Brown Dwarf Atmospheres: Infrared Spectroscopic Time Series Of L/T Transition Brown Dwarfs, D. Stephens, B. Goldman, M. C. Cushing, M. S. Marley, E. Artigau, K. S. Baliyan, V. J. S. Bejar, J. A. Caballero, N. Chanover, M. Connelley, R. Doyon, T. Forveille, S. Ganesh, C. R. Gelino, H. B. Hammel, J. Holtzman, S. Joshi, U. C. Joshi, S. K. Leggett, M. C. Liu

Faculty Publications

L-type ultra-cool dwarfs and brown dwarfs have cloudy atmospheres that could host weather-like phenomena. The detection of photometric or spectral variability would provide insight into unresolved atmospheric heterogeneities, such as holes in a global cloud deck. Indeed, a number of ultra-cool dwarfs have been reported to vary. Additional time-resolved spectral observations of brown dwarfs offer the opportunity for further constraining and characterising atmospheric variability. Aims. It has been proposed that growth of heterogeneities in the global cloud deck may account for the L- to T-type transition when brown dwarf photospheres evolve from cloudy to clear conditions. Such a mechanism is …


A Conceptual Model Of Groundwater Flow In Spring Valley, Nv, And Snake Valley, Nv-Ut, Jeremy Micheal Gillespie Feb 2008

A Conceptual Model Of Groundwater Flow In Spring Valley, Nv, And Snake Valley, Nv-Ut, Jeremy Micheal Gillespie

Theses and Dissertations

A geochemical study of major springs and wells in Spring Valley, Nevada, and Snake Valley, Utah-Nevada was initiated in response to the Clark, Lincoln and White Pine Counties Groundwater Development Project proposed by the South Nevada Water Authority (SNWA). Water budget estimates suggest that interbasin flow accounts for a significant portion (~25%) of the water budgets in Spring and Snake Valleys. Although interbasin flow is possible in some areas, alternative plausible explanations place significant uncertainty on water budget allocations. To examine the plausibility of local and interbasin flow paths the groundwater flow in Spring and Snake Valleys was evaluated using …


Quenching Of Highly Vibrationally Excited Pyrimidine By Collisions With Co4, Jeremy A. Johnson, Andrew M. Duffin, Brian J. Hom, Karl E. Jackson, Eric T. Sevy Feb 2008

Quenching Of Highly Vibrationally Excited Pyrimidine By Collisions With Co4, Jeremy A. Johnson, Andrew M. Duffin, Brian J. Hom, Karl E. Jackson, Eric T. Sevy

Faculty Publications

Relaxation of highly vibrationally excited pyrimidine (C4N2H4) by collisions with carbon dioxide has been investigated using diode laser transient absorption spectroscopy. Vibrationally hot pyrimidine (E'=40,635 cm^-1) was prepared by 248-nm excimer laser excitation, followed by rapid radiationless relaxation to the ground electronic state. The nascent rotational population distribution (J=58–80) of the 0000 ground state of CO2 resulting from collisions with hot pyrimidine was probed at short times following the excimer laser pulse. Doppler spectroscopy was used to measure the CO2 recoil velocity distribution for J=58–80 of the 0000 state. Rate constants and probabilities for collisions populating these CO2 rotational states …


Ozone Exposure In A Mouse Model Induces Airway Hyperreactivity That Requires The Presence Of Natural Killer T Cells And Il-17, Paul B. Savage, Muriel Pichavant, Sho Goya, Everett H. Meyer, Richard A. Johnston, Hye Y. Kim, Ponpan Matangkasombut, Ming Zhu, Yoichiro Iwakura, Rosemarie H. Dekruyff, Stephanie A. Shore, Dale T. Umetsu Feb 2008

Ozone Exposure In A Mouse Model Induces Airway Hyperreactivity That Requires The Presence Of Natural Killer T Cells And Il-17, Paul B. Savage, Muriel Pichavant, Sho Goya, Everett H. Meyer, Richard A. Johnston, Hye Y. Kim, Ponpan Matangkasombut, Ming Zhu, Yoichiro Iwakura, Rosemarie H. Dekruyff, Stephanie A. Shore, Dale T. Umetsu

Faculty Publications

Exposure to ozone, which is a major component of air pollution, induces a form of asthma that occurs in the absence of adaptive immunity. Although ozone-induced asthma is characterized by airway neutrophilia, and not eosinophilia, it is nevertheless associated with airway hyperreactivity (AHR), which is a cardinal feature of asthma. Because AHR induced by allergens requires the presence of natural killer T (NKT) cells, we asked whether ozone-induced AHR had similar requirements. We found that repeated exposure of wild-type (WT) mice to ozone induced severe AHR associated with an increase in airway NKT cells, neutrophils, and macrophages. Surprisingly, NKT cell-deficient …


Simulation And Visualization Of Environments With Multidimensional Time, Luther A. Tychonievich Jan 2008

Simulation And Visualization Of Environments With Multidimensional Time, Luther A. Tychonievich

Theses and Dissertations

This work introduces the notion of computational hypertime, or the simulation and visualization of hypothetical environments possessing multidimensional time. An overview of hypertime is provided,including an intuitive visualization paradigm and a discussion of the failure of common simulation techniques when extended to include multidimensional time. A condition for differential equations describing hypertime motion to be amenable to standard time-iterative simulation techniques is provided,but is not satisfied by any known model of physics. An alternate simulation algorithm involving iterative refinement of entire equations of motion is presented,with an example implementation to solve elastic collisions in hypertime. An artificial intelligence algorithm for …