Physical Sciences and Mathematics Commons^™

Analysis Of Chaos-Induced Pulse Trains In The Ionization Of Hydrogen, K. A. Mitchell, J. P. Handley, B. Tighe, A. Flower, John B. Delos

Arts & Sciences Articles

We examine excitation (by a short laser pulse) of a hydrogen atom in parallel electric and magnetic fields, from an initial tightly bound state to a state above the classical ionization threshold. We predict that the atom ionizes by emitting a train of electron pulses. This prediction is based on the classical dynamics of electron escape. In particular, the pulse train is due to classical chaos, which occurs for nonvanishing magnetic field. We connect the structure of the pulse train to fractal structure in the escape dynamics, and discuss several issues of experimental interest, with a particular emphasis on understanding …

Environmental Sustainability And The Traditional Tibetan Home, Katherine Shrader

Independent Study Project (ISP) Collection

In Tibetan Buddhism, the srivatsa, or glorious endless knot, reminds one of the truth of reality. Six right-angled, intertwined strands flow endlessly together, each one connected to the other, each one giving form to the next. So flows reality. Looking past the illusion of isolation, the endless knot illustrates the interdependence and mutual cooperation that runs the world.

No event, no living being has the ability to stand by itself, completely unaffected and unaffecting. All phenomena are intertwined. Every human action, however big or small, impacts the world in some way. The endless knot unveils the truth of reality so …

Art And Democracy In Environmental Decision Making, Audrey Stewart

Independent Study Project (ISP) Collection

Global doctrines on sustainable development emphasize public participation as a tenet of environmentally responsible development. Given the Czech government’s tepid stance towards implementing sustainability measures, much impetus for realizing them will have to come from other facets of Czech society, including the public. In spite of the nearly populist feel of a mounting environmental movement in the late 1980s, after the Velvet Revolution the Czech public remained relatively disengaged from environmental involvement. Traditional decision-making venues within the Czech Republic now actively exclude the public from participating, while other pressures stemming from history and present also diminish the public impetus for …

Noao Fundamental Plane Survey. I. Survey Design, Redshifts, And Velocity Dispersion Data, Russell J. Smith, Michael J. Hudson, Jenica E. Nelan, Stephen A. W Moore, Stephen J. Quinney, Gary A. Wegner, John R. Lucey, Roger L. Davies, Justin J. Malecki, David Schade, Nicholas B. Suntzeff

Dartmouth Scholarship

We introduce the NOAO Fundamental Plane Survey (NFPS), a wide-field imaging/spectroscopic study of rich, low-redshift galaxy clusters. The survey targets X-ray–selected clusters at 0.010 < z < 0.067, distributed over the whole sky, with imaging and spectroscopic observations obtained for 93 clusters. This data set will be used in investigations of galaxy properties in the cluster environment and of large-scale velocity fields through the fundamental plane. In this paper, we present details of the cluster sample construction and the strategies employed to select early-type galaxy samples for spectroscopy. Details of the spectroscopic observations are reported. From observations of 5479 red galaxies, we present redshift measurements for 5388 objects and internal velocity dispersions for 4131. The velocity dispersions have a median estimated error ~7%. The NFPS has ~15% overlap with previously published velocity dispersion data sets. Comparisons to these external catalogs are presented and indicate typical external errors of ~8%.

Modeling And Simulation Of Photonic Crystal Fibers Using Finite Difference Frequency Domain Method, Md. Khalid Ikram

Electrical & Computer Engineering Theses & Dissertations

Photonic crystal fibers (PCFs) allow guiding light in low-index core. These fibers exhibit properties such as single-mode operation in broad wavelength region. The mode shape and group velocity dispersion can be controlled by designing the microstructures of the cladding. In order to study these properties, a fast, efficient, and highly accurate numerical modeling method is required.

A full-vectorial finite-difference frequency-domain (FDFD) method is implemented. The modal properties of conventional step index fiber and index-guiding PCF are analyzed using this modeling technique. Compared to plane wave expansion and biorthogonal basis methods, FDFD is found to be simple, reliable, and efficient. PCFs …

Bottleneck Analysis Of Cports, Sreekalyana Chakravarthy Kajuluri

Electrical & Computer Engineering Theses & Dissertations

CPortS is a transportation logistics simulation that models the flow of military cargo through a seaport and the interaction of the cargo with the port resources and infrastructure. It provides information about the seaport's capabilities, how the cargo has been handled, how many days the cargo took to clear a particular port area, and the overall throughput of the seaport. The model is highly data intensive since it models the huge traffic in a real seaport.

Bottlenecks reduce system performance. Systems that are traffic intensive or simulations of systems, which are data intensive, encounter bottlenecks, which reduce their performance. In …

Hierarchical Hybrid Multicast An End System Multicast Algorithm Approach, Guillermo Loaisiga

Electrical & Computer Engineering Theses & Dissertations

Due to the rapid development in the computer and communication technologies, the Internet is experiencing an increasing demand of high-speed, real-time distributed applications, such as live streaming multimedia, videoconferencing, distributed simulations, and multiparty games. Multicast is an efficient transmission mechanism to support these applications. Historically, IP Multicast (IPM) has provided multicast support with well-known benefits, especially in bandwidth savings. However, it has experienced little deployment due to economic and architectural limitations.

Overlay multicast holds promise for the implementation of large scale Internet multicast services. An overlay network is a virtual topology constructed on top of the Internet infrastructure. This concept …

Automatic Image Orientation Determination With Natural Image Statistics, Siwei Lyu

Computer Science Technical Reports

In this paper, we propose a new method for automatically determining image orientations. This method is based on a set of natural image statistics collected from a multi-scale multi-orientation image decomposition (e.g., wavelets). From these statistics, a two-stage hierarchal classification with multiple binary SVM classifiers is employed to de- termine image orientation. The proposed method is evaluated and compared to existing methods with experiments performed on 18040 natural images, where it showed promising performance.

Vector Operations In Superscalar Architectures, Nathan Daniel Flinn

Electrical & Computer Engineering Theses & Dissertations

Vector calculations are very prevalent today. Though the vector-processing computer is quite an old concept, superscalar processors lack hardware support for vector operations. This thesis investigates whether an ordinary superscalar computer architecture can be designed to include hardware support for improved vector operations without drastically changing the existing superscalar design and behavior. A computer architecture design was created and implemented that included the vector multiply (dot product) operation. The design includes a Vector Operations Unit that captures incoming vector operations and generates the necessary set of machine instructions to complete the vector operation internally. It then delivers these instructions to …

The Crest, Fall 2004, Virginia Institute Of Marine Science

Reports

Table of Contents:

• NOAA Opens Chesapeake Bay Office in Virginia at VIMS
• Team discovers probable cause of croaker deaths
• Researchers test and refine storm-surge models
• Dye helps predict potential dispersal of non-native oyster larvae
• Researchers release juvenile blue crabs
• Annual wetlands workshop explores Isabel's impacts
• Fellows earn berth at EPA Conference
• Reay and Priest share Spirit award
• Schaffner briefs U.S. Congress
• VIMS student develops educational board game
• VIMS hosts release of Fisheries Ecosystem plan
• Researchers study ocean's "internal weather"
• VIMS mourns passing of Andrews
• News Briefs

Huffman Approach To Opcode Compression, Jason B. Shreve

Electrical & Computer Engineering Theses & Dissertations

Instructions are the building blocks of computer programs. They are composed of opcodes, which uniquely identify each instruction, and the operands or data. In most architectures, the instruction length is a set multiple of the word size. The size and number of operands vary by instruction. Due to programmer usage, program need, or compiler design, opcodes do not occur with a constant distribution. Likely, some opcodes occur very frequently, whereas others occur very infrequently or not at all. If the length of an opcode were representative of its frequency, compression in program size might be achieved.

This thesis is an …

Bacterial Degradation Of Disinfection By-Products In Drinking Water, Laura Inga Fauntleroy

Chemistry & Biochemistry Theses & Dissertations

Chlorine became a major disinfectant for the removal of microbial contaminants in 1914. Current water chlorination procedures yield halogenated disinfection byproducts (DBPs), such as haloalkanes and haloacetic acids (HAAs), due to the reaction of chlorine with naturally occurring organic compounds. Various water utilities have observed decreased HAAs levels in maximum residence time locations (MRTLs), where they were expected to be higher. These MRTLs have low free chlorine residual and high heterotrophic bacteria plate counts. Xanthobacter autotrophicus, GJ-10, is a bacterium that has been shown to contain dehalogenase enzymes and, therefore, can biodegrade HAAs. A number of water-system bacteria were …

Hydrologic Variations Within Created And Natural Wetlands In Southeastern Virginia, Aaron Dyer Despres

OES Theses and Dissertations

The hydrology of wetlands, particularly how wetland soils collect, store, and redistribute water strongly affects how wetland systems function. In created wetlands, construction processes and materials influence the hydrology and consequently, the potential for successful reestablishment of target vegetation communities. During .2002- 2004, the Virginia Department of Transportation constructed large mitigation wetlands on two different Quaternary aged surfaces with very similar hydrogeomorphic conditions. The Sandy Bottom Nature Park site (SBNP) located in Hampton, VA and rests on the sandy loam Tabb Formation while the Charles City Wetland site (CCW) lies on the older and clay-rich Shirley Formation. This study documents …

Design And Analysis Of A Cooperative Medium Access Scheme For Wireless Mesh Networks, Arup Acharya, Archan Misra, Sorav Bansal

Research Collection School Of Computing and Information Systems

This paper presents the detailed design and performance analysis of MACA-P, a RTS/CTS based MAC protocol, that enables simultaneous transmissions in wireless mesh networks. The IEEE 802.11 DCF MAC prohibits any parallel transmission in the neighborhood of either a sender or a receiver (of an ongoing transmission). MACA-P is a set of enhancements to the 802.11 MAC that allows parallel transmissions in situations when two neighboring nodes are either both receivers or transmitters, but a receiver and a transmitter are not neighbors. The performance of MACA-P in terms of system throughput is obtained through a simulation of the protocol using …

Badia Rangeland Rehabilitation: Community Participation, Raed Al-Tabini, H. Soub

Raed Al-Tabini

No abstract provided.

Simulation Of High Intensity Laser Pulse Propagation Through Optical Systems, Jeremy Gulley, Erik Zeek, William Dennis

Jeremy R. Gulley

No abstract is currently available.

Studies Of The Relationship Between The Structure And Properties Of Interfacial Thin Films, Mark Anderson

Mark R. Anderson

No abstract is available at this time.

An Entrepreneur's Dilemma : To Swot Or Not To Swot, A. Desai Chaanakya, Arcot Desai Narasimhalu

Arcot Desai NARASIMHALU

This work presents an updated and revised model for evaluating companies using a 'snapshot' analysis. Historically, the SWOT model has been the preferred analysis tool, but with an increasing number of entrepreneurs faced with a non-mature market, a new tool must be developed for accurate analysis.

Knowledge Discovery From Multispectral Satellite Images, Arun D. Kulkarni

Arun Kulkarni

Technical Note: Comparative Static Analysis Of Information Value In A Canonical Decision Problem, Jeffrey Keisler

Jeffrey Keisler

To gain insight into the behavior of the value of information, this paper identifies specific rules for a canonical decision problem: the two-act linear loss decision with normal prior probability distributions. Conditions are derived for which the expected value of perfect information increases when mean and standard deviation are both linear functions of an exogenous variable. A variety of richer decision problems can be adapted to the problem, so that the general results obtained here can be immediately applied to understand drivers of information value.

Time-Warped Longest Common Subsequence Algorithm For Music Retrieval, Anyuan Guo, Hava Siegelmann

Hava Siegelmann

Recent advances in music information retrieval have enabled users to query a database by singing or humming into a microphone. The queries are often inaccurate versions of the original songs due to singing errors and errors introduced in the music transcription process. In this paper, we present the Time-Warped Longest Common Sub-sequence algorithm (T-WLCS), which deals with singing errors involving rhythmic distortions. The algorithm is employed on song retrieval tasks, where its performance is compared to the longest common subsequence algorithm.

Asymptotic Accuracy Of Geoacoustic Inversions, Michele Zanolin, Ian Ingram, Aaron Thode, Nicholas C. Makris

Michele Zanolin

Stimulated Raman Backscattering Of Laser Radiation In Deep Plasma Channels, Serguei Y. Kalmykov, Gennady Shvets

Serge Youri Kalmykov

Stimulated Raman backscattering (RBS) of intense laser radiation confined by a single-mode plasma channel with a radial variation of plasma frequency greater than a homogeneous-plasma RBS bandwidth is characterized by a strong transverse localization of resonantly driven electron plasma waves (EPW). The EPW localization reduces the peak growth rate of RBS and increases the amplification bandwidth. The continuum of nonbound modes of backscattered radiation shrinks the transverse field profile in a channel and increases the RBS growth rate. Solution of the initial-value problem shows that an electromagnetic pulse amplified by the RBS in the single-mode deep plasma channel has a …

Optically Thick Clumps – Not The Solution To The Wolf-Rayet Wind Momentum Problem?, J. C. Brown, J. P. Cassinelli, Q. Li, A. F. Kholtygin, R. Ignace

Richard Ignace

The hot star wind momentum problem eta = M-upsiloninfinity/(L/c) much greater than 1 is revisited, and it is shown that the conventional belief, that it can be solved by a combination of clumping of the wind and multiple scattering of photons, is not self-consistent for optically thick clumps. Clumping does reduce the mass loss rate. M, and hence the momentum supply, required to generate a specified radio emission measure epsilon, while multiple scattering increases the delivery of momentum from a specified stellar luminosity L. However, in the case of thick clumps, when combined the two effects act in opposition rather …

Thermoelectricity In Natural And Synthetic Hydrogels, Brandon R. Brown

Physics and Astronomy

We describe a technique for measuring a Seebeck effect in gels and present data for three systems. notably distinct signals are obtained for gel originating in the electrosensitive organs of marine sharks, syntehtic collagen-based gel, and as a control, seawater, the gels' seawater simply confirms that gels suppress mass transport. The difference between synthetic gel and the gel of sharks shows that the charged polymers of the shark gel restrict mass transport much more successfully than the polumers of the collagen gel, and we submit that this sort of ion localization is key to the emergence of thermoelectricity in a …

Developing A Sensing System For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic: Quarterly Progress Report (July 1 – Sept. 30, 2004), Yingtao Jiang, Bingmei Fu

Transmutation Sciences Materials (TRP)

Dr. Jiang Ma and Mr. Xiaolong Wu worked in LANL between July 1 and Sept. 15 to conduct the experiment. Test of the corrosion of different materials in LBE was performed. The influence of the process of gas introduction to the LBE was studied. Data analysis work was performed based on accumulated data. In the same time, progress has been made in the simulation for transport in oxygen mixing, and one paper was presented in a conference. Another paper was composed and submitted to IEEE International Symposium of Circuits and Systems for the track Chemical Sensors. Preparation of a paper …

Cooperative Conservation - Interagency Volunteer Program Quarterly Progress Report: Period Ending September 30, 2004, Margaret N. Rees

Get Outdoors Nevada

Collaboration with Interagency Team

Although the task agreement formally commenced June 30, 2004, the agreement was not fully executed by both parties until July 29, 2004. In the first three months of this agreement, UNLV representatives have met with or communicated via email with the Interagency Volunteer Team on numerous occasions. At the first meeting on July 13, 2004, Government Technical Representative Bobbie Antonich and UNLV Public Lands Initiative Director Nancy Flagg met with the interagency team to discuss the overall goals for the Interagency Volunteer Program (IVP). The team was brought up-to-date on the status of the task agreement, …

Heights And Diophantine Problems, Lenny Fukshansky

CMC Faculty Publications and Research

Lecture given at Rice University, September 2004.

Network-Layer Selective Security, Casey T. Deccio

Theses and Dissertations

The Internet and other large computer networks have become an integral part of numerous daily processes. Security at the network layer is necessary to maintain infrastructure survivability in the case of cyber attacks aimed at routing protocols. In order to minimize undesired overhead associated with added security at this level, the notion of selective security is proposed. This thesis identifies elements in network topologies that are most important to the survivability of the network. The results show that the strategic placement of network security at critical elements will improve overall network survivability without the necessity of universal deployment.

Development Of A Systems Engineering Model Of The Chemical Separations Process, Yitung Chen, Sean Hsieh

Separations Campaign (TRP)

The whole chemical separation process is complex to the point that definitely requires certain level of systematic coordination. To perform smoothly and meet the target extraction rates among those processes, this research proposed a general-purpose systems engineering model.

A general purposed systems engineering model, Transmutation Research Program System Engineering Model Project (TRPSEMPro), was developed based on the above design concept. The system model includes four main parts: System Manager, Model Integration, Study Plan, and Solution Viewer. System Manager supervises all the case (problem) creation, and functionality definition. Model Integration identifies chemical extraction processes and their execution sequence. Study Plan is …