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2003

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Articles 2011 - 2040 of 3876

Full-Text Articles in Physical Sciences and Mathematics

Effect Of Multi-Mode Vibration On Signature Estimation Using A Laser Vibration Sensor, Ngoya Pepela Mar 2003

Effect Of Multi-Mode Vibration On Signature Estimation Using A Laser Vibration Sensor, Ngoya Pepela

Theses and Dissertations

A laser vibration sensor (LVS) can be used to determine the vibrational spectrum of targets such as vehicles using heterodyne laser Doppler velocimetry. The vibrational spectra of exterior skin of vehicles are known to have characteristic resonances due to the physical structure driven by motor gears and other moving parts. Each particular class of vehicle has a unique vibrational spectrum. This research shows how a body vibrating in higher order modes has the opportunity to eliminate spectral content of the target's vibrational spectrum while using an LVS to perform spectrum estimation. This is due to roughly equal amounts of laser …


Status Of The Major Oyster Diseases In Virginia 2002 A Summary Of The Annual Monitoring Program, Lisa M. Ragone Calvo, Eugene M. Burreson Mar 2003

Status Of The Major Oyster Diseases In Virginia 2002 A Summary Of The Annual Monitoring Program, Lisa M. Ragone Calvo, Eugene M. Burreson

Reports

Samples collected monthly from the upper James River sites from January through May showed a decline in P. marinus prevalence during the 4 winter and spring following a typical annual pattern; however, annual minimums were atypically high, particularly at Point of Shoals and Wreck Shoal (12-44%). Unusually high salinity conditions and warm winter temperatures promoted high overwintering survival of the pathogen and an early onset of the disease in the summer months. Perkinsus marinus prevalence increased to 100% at all four of the upper river stations and record high infection intensities were observed at Deepwater Shoal and Horsehead Rock. It …


Single-Mode Raman Fiber Laser In A Multimode Fiber, Matthew B. Crookston Mar 2003

Single-Mode Raman Fiber Laser In A Multimode Fiber, Matthew B. Crookston

Theses and Dissertations

The feasibility of a transverse single-mode Raman fiber laser using a multimode fiber has been investigated. The Raman fiber laser operates in low-order transverse modes despite the fact the fiber supports multimode beam propagation. The performance characteristics of the Raman fiber laser are compared with those of the single-pass SRS beam.


A Three-Dimensional Heads-Up Primary Navigation Reference Display For Paratroopers Performing High Altitude High Open Jumps, Brian A. Balazs Mar 2003

A Three-Dimensional Heads-Up Primary Navigation Reference Display For Paratroopers Performing High Altitude High Open Jumps, Brian A. Balazs

Theses and Dissertations

The Department of Defense (DoD) relies on the para-dropping of resources to meet different objectives in order to accomplish missions during peace-time, war-time, or military operations other than war. The resources dropped to the ground via parachute range from supplies and equipment to the most valued asset, people. Tactics have been developed to increase the safety of troops parachuting into areas of conflict. These tactics include high-altitude high-opening (HAHO) jumping and night jumping. HAHO jumping allows paratroopers to travel large distances in the air away from the path of the delivering aircraft. While night jumping, done with the aid of …


Searching System Call Information For Clues: The Effects Of Intrusions Of Processes, Mark G. Reith Mar 2003

Searching System Call Information For Clues: The Effects Of Intrusions Of Processes, Mark G. Reith

Theses and Dissertations

The United States Air Force extensively uses information systems as a tool managing and maintaining its information. The increased dependence on these systems in recent years has necessitated the need for protection front threats of information warfare and cyber terrorism. One type of protection utilizes intrusion detection systems to provide indications that intrusive behavior has occurred. Other types of protection may include packet filtering, cryptography and strong user authentication. Traditional approaches toward intrusion detection rely on features that are external to computer processes. By treating processes as black-boxes, intrusion detection systems may miss a wealth of information that could be …


Remote Sensing Systems Optimization For Geobase Enhancement, Steve J. Paylor Mar 2003

Remote Sensing Systems Optimization For Geobase Enhancement, Steve J. Paylor

Theses and Dissertations

The U.S. Air Force is in the process of implementing GeoBase, a geographic information system (GIS), throughout its worldwide installations, Air Force GIS needs can be augmented by imagery from aerial and satellite platforms. Imagery has greatly improved over the past several years and provides high resolution coverage of features on earth. Various imagery types will significantly increase GeoBase usefulness in a range of mission requirements, Potential Air Force uses of imagery include identifying heat loss, environmental monitoring, command decision-making, and emergency response, The research develops a decision tool to determine the appropriate imagery for a given Air Force Application, …


Text Manipulation Judgment Accuracy: An Exploratory Study, Randy S. Wardak Mar 2003

Text Manipulation Judgment Accuracy: An Exploratory Study, Randy S. Wardak

Theses and Dissertations

Deception aims to affect a decision-making process in a way that somehow benefits the deceiver. More knowledge is desired in the area of purely text-based scenarios. Thirty-seven graduate students at the Air Force Institute of Technology participated in an experiment in order to gain an initial understanding of how people determine whether text has been manipulated, and to identify specific areas that may be more closely investigated in future research. Excerpts were drawn from editions of a current-events newsletter that the participants receive on a weekly basis as part of their enrollment in the graduate program. Some of the excerpts …


Detection Of Special Nuclear Material With High Purity Germanium (Hpge) And Mercuric Iodide (Hgi2) Gamma Detectors, Michael B. Nelson Mar 2003

Detection Of Special Nuclear Material With High Purity Germanium (Hpge) And Mercuric Iodide (Hgi2) Gamma Detectors, Michael B. Nelson

Theses and Dissertations

The Defense Threat Reduction Agency (DTRA) contracted for two gamma radiation detectors: mercuric iodide (HgI2) and electromechanically cooled (EMC) high purity germanium (HPGe) to support arms control inspection efforts. This project investigated whether these detectors could measure the quality and quantity of special nuclear material (SNM), particularly Pu-239 for the treaty verification mission. The project investigated two areas of detector capabilities: 1) HgI2 and HPGe detector performance necessary to characterize the quality of plutonium and the presence of shielding materials and 2) HgI2 and EMC HPGe detector performance degradation by high noise levels and EMC HPGe …


Explicit Building-Block Multiobjective Genetic Algorithms: Theory, Analysis, And Developing, Jesse B. Zydallis Mar 2003

Explicit Building-Block Multiobjective Genetic Algorithms: Theory, Analysis, And Developing, Jesse B. Zydallis

Theses and Dissertations

This dissertation research emphasizes explicit Building Block (BB) based MO EAs performance and detailed symbolic representation. An explicit BB-based MOEA for solving constrained and real-world MOPs is developed the Multiobjective Messy Genetic Algorithm II (MOMGA-II) which is designed to validate symbolic BB concepts. The MOMGA-II demonstrates that explicit BB-based MOEAs provide insight into solving difficult MOPs that is generally not realized through the use of implicit BB-based MOEA approaches. This insight is necessary to increase the effectiveness of all MOEA approaches. In order to increase MOEA computational efficiency parallelization of MOEAs is addressed. Communications between processors in a parallel MOEA …


Inquisitive Pattern Recognition, Amy L. Magnus Mar 2003

Inquisitive Pattern Recognition, Amy L. Magnus

Theses and Dissertations

The Department of Defense and the Department of the Air Force have funded automatic target recognition for several decades with varied success. The foundation of automatic target recognition is based upon pattern recognition. In this work, we present new pattern recognition concepts specifically in the area of classification and propose new techniques that will allow one to determine when a classifier is being arrogant. Clearly arrogance in classification is an undesirable attribute. A human is being arrogant when their expressed conviction in a decision overstates their actual experience in making similar decisions. Likewise given an input feature vector, we say …


Optical Characterization Of Antimony-Based, Types-I And Ii, Multiple Quantum-Well Semiconductor Structures For Mid-Infrared Laser Applications, Edward G. Ferguson Mar 2003

Optical Characterization Of Antimony-Based, Types-I And Ii, Multiple Quantum-Well Semiconductor Structures For Mid-Infrared Laser Applications, Edward G. Ferguson

Theses and Dissertations

This experiment characterizes antimony-based, multiple quantum-well, types-I and -II, semiconductor samples designed for laser applications. The samples emit light in the 3-5-micron range to exploit an atmospheric transmission window, making them ideal for infrared (IR)-seeking missile countermeasures. Photoluminescence (PL) spectra were collected and yielded bandgap (E(sub g)) dependence-on-temperature relationships. The type-I sample was found to follow the Varshni equation, while the type-II samples showed a rise with temperature in a portion of the curve that should be linear according to the Varshni equation. The type-II samples followed the Varshni equation well at higher temperature. The PL study indicated that the …


Reverse Geographic Location Of A Computer Node, Clinton G. Carr Iii Mar 2003

Reverse Geographic Location Of A Computer Node, Clinton G. Carr Iii

Theses and Dissertations

The determination of methods by which a user is able to locate his computer when that user does not know his current location, termed "homestation", will provide the Air Force an advantage over its adversaries. The methods are a combination of different mathematical techniques that enable the user to manipulate data to minimize the effects of delay caused by various factors on the network. The techniques use the smallest round trip time obtained from the ping utility. This time is then converted into miles and plotted on a map of the United States. The methods used to solve this problem …


An Artificial Immune System Strategy For Robust Chemical Spectra Classification Via Distributed Heterogeneous Sensors, Mark A. Esslinger Mar 2003

An Artificial Immune System Strategy For Robust Chemical Spectra Classification Via Distributed Heterogeneous Sensors, Mark A. Esslinger

Theses and Dissertations

The timely detection and classification of chemical and biological agents in a wartime environment is a critical component of force protection in hostile areas. Moreover, the possibility of toxic agent use in heavily populated civilian areas has risen dramatically in recent months. This thesis effort proposes a strategy for identifying such agents vis distributed sensors in an Artificial Immune System (AIS) network. The system may be used to complement "electronic" nose ("E-nose") research being conducted in part by the Air Force Research Laboratory Sensors Directorate. In addition, the proposed strategy may facilitate fulfillment of a recent mandate by the President …


Uml Assisted Visual Debugging For Distributed Systems, Benjamin R. Musial Mar 2003

Uml Assisted Visual Debugging For Distributed Systems, Benjamin R. Musial

Theses and Dissertations

The DOD is developing a Joint Battlespace Infosphere, linking a large number of data sources and user applications. To assist in this process, debugging and analysis tools are required. Software debugging is an extremely difficult cognitive process requiring comprehension of the overall application behavior, along with detailed understanding of specific application components. This is further complicated with distributed systems by the addition of other programs, their large size and synchronization issues. Typical debuggers provide inadequate support for this process, focusing primarily on the details accessible through source code. To overcome this deficiency, this research links the dynamic program execution state …


Optimizing An In Situ Bioremediation Technology To Manage Perchlorate-Contaminated Groundwater, Mark R. Knarr Mar 2003

Optimizing An In Situ Bioremediation Technology To Manage Perchlorate-Contaminated Groundwater, Mark R. Knarr

Theses and Dissertations

Combining horizontal flow treatment wells (HFTWs) with in situ biodegradation is an innovative approach with the potential to remediate perchlorate-contaminated groundwater. A technology model was recently developed that combines the groundwater flow induced by HFTWs with in situ biodegration processes that result from using the HFTWs to mix electron donor into perchlorate-contaminated groundwater. A field demonstration of this approach is planned to begin this year. In order to apply the technology in the field, project managers need to understand how contaminated site conditions and technology design parameters impact technology performance. One way to gain this understanding is to use the …


Analysis Of Anion Distributions In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Joshua D. Kovacic Mar 2003

Analysis Of Anion Distributions In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Joshua D. Kovacic

Theses and Dissertations

Perchloroethene (PCE), Trichloroethene (TCE) and their degradation products are among the most common organic groundwater contaminants in the United States. Constructed wetlands utilizing upward flow harbor reduction-oxidation conditions that have demonstrated the potential to promote both partial and total mineralization of PCE and TCE through the process of natural attenuation. Organic acid and inorganic anion concentrations are indicative of reduction-oxidation processes that drive chlorinated ethene degradation. These analytes were investigated to assess their development within three vertically stratified regions of a constructed wetland cell at Wright-Patterson Air Force Base fed by groundwater contaminated with PCE and TCE. Data collected during …


Palladium-Catalyzed Destruction Of Nitro Aromatic-Contaminated Groundwater, Dennis Landon Phillips Mar 2003

Palladium-Catalyzed Destruction Of Nitro Aromatic-Contaminated Groundwater, Dennis Landon Phillips

Theses and Dissertations

Of the over 17,000 DoD sites that potentially require remediation, sites containing soil and groundwater contaminated by energetic compounds are prevalent (Larson et al., 2001). Production of energetics such as 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5 - trinitro- 1,3,5 -triazine (RDX), and octahydro-1,3,5,7-tetranitro- 1,3,5,7-tetrasocine (HMX) for use in munitions has created a DoD-wide problem due to improper disposal techniques (Price et al., 2001), Nitro aromatic compounds (NACs) similar to those used in explosives can also be found in insecticides, herbicides, pharmaceuticals, dyes, plastics, and many other commonly used products. The natural breakdown of these contaminants creates byproducts such as amines, which are known …


Feature Guided Image Registration Applied To Phase And Wavelet-Base Optic Flow, Kate R. Duffy Mar 2003

Feature Guided Image Registration Applied To Phase And Wavelet-Base Optic Flow, Kate R. Duffy

Theses and Dissertations

Optic Flow algorithms are useful in problems such as computers vision, navigational systems, and robotics. However, current algorithms are computationally expensive or lack the accuracy to be effective compared with traditionally navigation systems. Recently, lower accuracy inertial navigation systems (INS) based on Microelectromechanical systems (MEMS) technology have been proposed to replace more accurate traditional navigation systems.


Forecasting Excessive Rainfall And Low-Cloud Bases East Of The Northern Andes And Mesoscale Convective Complex Movement In Central South America, Marc R. Gasbarro Mar 2003

Forecasting Excessive Rainfall And Low-Cloud Bases East Of The Northern Andes And Mesoscale Convective Complex Movement In Central South America, Marc R. Gasbarro

Theses and Dissertations

This research produces better forecast tools for SOUTHCOM's 25th Operational Weather Squadron (OWS) over multiple areas of operation in South America. Heavy rainfall and low-cloud base events along the northeastern Andes foothills are examined, as well as, mesoscale convective complexes (MCCs) in Central South America (CSA). Low clouds, fog, and flooding rains hamper daily Department of Defense (DoD) counter-drug operations in Northwestern South America (NWSA). In addition, fierce MCCs interfere with joint-military exercises in CSA.


Statistical Process Control: An Application In Aircraft Maintenance Management, Bradley A. Beabout Mar 2003

Statistical Process Control: An Application In Aircraft Maintenance Management, Bradley A. Beabout

Theses and Dissertations

Maintenance management at the 135th Airlift Wing, Maryland Air National Guard desires a visualization tool for their maintenance performance metrics. Currently they monitor their metrics via an electronic spreadsheet. They desire a tool that presents the performance information in a graphical manner. This thesis effort focuses on the development of a visualization tool utilizing two of the seven tools offered by Statistical Process Control (SPC). This research demonstrates the application of p-charts and Pareto diagrams in the aircraft maintenance arena. P-charts are used for displaying mission capable (MC) rates and flying scheduling effectiveness (FSE) rates. Pareto diagrams are then used …


Wayne E. Sabbe Arkansas Soil Fertility Studies 2002, Nathan A. Slaton Mar 2003

Wayne E. Sabbe Arkansas Soil Fertility Studies 2002, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts also be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies contained within will allow producers to compare their practices with the university’s research efforts. Additionally, soil test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.


Book Review: Strange Matters: Undiscovered Ideas At The Frontiers Of Space And Time, T. D. Oswalt Mar 2003

Book Review: Strange Matters: Undiscovered Ideas At The Frontiers Of Space And Time, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Strange Matters: Undiscovered Ideas at the Frontiers of Space and Time by Tom Siegfried. John Henry, 2002 307p, 0-309-08407-5 $24.95.


Infinitely Many Hyperbolic 3-Manifolds Which Contain No Reebless Foliation, R. Roberts, J. Shareshian, Melanie Stein Mar 2003

Infinitely Many Hyperbolic 3-Manifolds Which Contain No Reebless Foliation, R. Roberts, J. Shareshian, Melanie Stein

Faculty Scholarship

We investigate group actions on simply-connected (second countable but not necessarily Hausdorff) 1-manifolds and describe an infinite family of closed hyperbolic 3-manifolds whose fundamental groups do not act nontrivially on such 1-manifolds. As a corollary we conclude that these 3-manifolds contain no Reebless foliation. In fact, these arguments extend to actions on oriented -order trees and hence these 3-manifolds contain no transversely oriented essential lamination; in particular, they are non-Haken.


Energy-Efficient Broadcast And Multicast Trees For Reliable Wireless Communication, Suman Banerjee, Archan Misra, Jihwang Yeo, Ashok Agrawala Mar 2003

Energy-Efficient Broadcast And Multicast Trees For Reliable Wireless Communication, Suman Banerjee, Archan Misra, Jihwang Yeo, Ashok Agrawala

Research Collection School Of Computing and Information Systems

We define energy-efficient broadband and multicast schemes for reliable communication in multi-hop wireless networks. Unlike previous techniques, the choice of neighbors in the broadband and multicast trees in these schemes, are based not only on the link distance, but also on the error rates associated with the link. Our schemes can be implemented using both positive and negative acknowledgement based reliable broadcast techniques in the link layer. Through simulations, we show that our scheme achieves up to 45% improvement over previous schemes on realistic 100-node network topologies. A positive acknowledgment based implementation is preferred. Our simulations show that the additional …


Maca-P: A Mac For Concurrent Transmissions In Multi-Hop Wireless Networks, Arup Acharya, Archan Misra, Sorav Bansal Mar 2003

Maca-P: A Mac For Concurrent Transmissions In Multi-Hop Wireless Networks, Arup Acharya, Archan Misra, Sorav Bansal

Research Collection School Of Computing and Information Systems

This paper presents the initial design and performance study of MACA-P, a RTS/CTS based MAC protocol that enables simultaneous transmissions in multihop ad-hoc wireless networks. Providing such low-cost multihop and high performance wireless access networks is an important enabler of pervasive computing. MACA-P is a set of enhancements to the 802.11 DCF that allows parallel transmissions in many situations when two neighboring nodes are either both receivers or both transmitters, but a receiver and a transmitter are not neighbors. Like 802.11, MACA-P contains a contention-based reservation phase prior to data transmission. However, the data transmission is delayed by a control …


Adaptive Transmission Power For Optimal Energy Reliable Multi-Hop Wireless Communication, Suman Banerjee, Archan Misra Mar 2003

Adaptive Transmission Power For Optimal Energy Reliable Multi-Hop Wireless Communication, Suman Banerjee, Archan Misra

Research Collection School Of Computing and Information Systems

We define a transmission power adaptation-based routing technique that finds optimal paths for minimum energy reliable data transfer in multi-hop wireless networks. This optimal choice of the transmission power depends on the link distance between the two nodes and the channel characteristics. Typical energy efficient routing techniques use a transmission power such that the received signal power at the destination minimally exceeds a desired threshold signal strength level. In this paper we argue that such a choice of the transmission power does not always lead to optimal energy routes, since it does not consider differences in the receiver noise levels. …


Hierarchical Text Classification Methods And Their Specification, Ee Peng Lim, Aixin Sun, Wee-Keong Ng Mar 2003

Hierarchical Text Classification Methods And Their Specification, Ee Peng Lim, Aixin Sun, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

Hierarchical text classification refers to assigning text documents to the categories in a given category tree based on their content. With large number of categories organized as a tree, hierarchical text classification helps users to find information more quickly and accurately. Nevertheless, hierarchical text classification methods in the past have often been constructed in a proprietary manner. The construction steps often involve human efforts and are not completely automated. In this chapter, we therefore propose a specification language known as HCL (Hierarchical Classification Language). HCL is designed to describe a hierarchical classification method including the definition of a category tree …


Motion Analysis And Segmentation Through Spatio-Temporal Slices Processing, Chong-Wah Ngo, Ting-Chuen Pong, Hong-Jiang Zhang Mar 2003

Motion Analysis And Segmentation Through Spatio-Temporal Slices Processing, Chong-Wah Ngo, Ting-Chuen Pong, Hong-Jiang Zhang

Research Collection School Of Computing and Information Systems

This paper presents new approaches in characterizing and segmenting the content of video. These approaches are developed based upon the pattern analysis of spatio-temporal slices. While traditional approaches to motion sequence analysis tend to formulate computational methodologies on two or three adjacent frames, spatio-temporal slices provide rich visual patterns along a larger temporal scale. In this paper, we first describe a motion computation method based on a structure tensor formulation. This method encodes visual patterns of spatio-temporal slices in a tensor histogram, on one hand, characterizing the temporal changes of motion over time, on the other hand, describing the motion …


Comparing The Routing Energy Overheads Of Ad-Hoc Routing Protocols, Sorav Bansal, Rajeev Shorey, Archan Misra Mar 2003

Comparing The Routing Energy Overheads Of Ad-Hoc Routing Protocols, Sorav Bansal, Rajeev Shorey, Archan Misra

Research Collection School Of Computing and Information Systems

We use simulations to study the comparative routing overheads of three ad-hoc routing protocols, namely AODV, DSDV and DSR. In contrast to earlier studies, we focus exclusively on the energy consumption and not on other metrics such as the number of routing packets. In particular, we study the `range effects' of the three protocols, i.e., how changes to the transmission power and transmission radius affect the overall energy consumed by routing-related packets. Due to the broadcast nature of the wireless medium, the energy spent in packet receptions is almost as important as the transmission power; using the number of transmissions …


Gulf River Estuary Natural Resources Inventory, Chantal Lefebvre, Dan Hellin, Chris Crawford Mar 2003

Gulf River Estuary Natural Resources Inventory, Chantal Lefebvre, Dan Hellin, Chris Crawford

Urban Harbors Institute Publications

The purpose of this analysis is to inventory the present assemblage of natural resources in the vicinity of the Gulf River estuary as well as to provide information on land use, recreational use, and pollution threats and concerns. The inventory summarizes existing research and the knowledge and experience of local experts and residents who are most familiar with the Gulf River’s natural environment. It could be used as the first step toward producing a resource management plan for the Gulf River estuary.

The analysis was initiated and funded by the Gulf River Association and prepared to serve as a reference …