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Articles 2731 - 2760 of 3529

Full-Text Articles in Physical Sciences and Mathematics

Structure And Properties Of Maximal Outerplanar Graphs., Benjamin Allgeier Aug 2009

Structure And Properties Of Maximal Outerplanar Graphs., Benjamin Allgeier

Electronic Theses and Dissertations

Outerplanar graphs are planar graphs that have a plane embedding in which each vertex lies on the boundary of the exterior region. An outerplanar graph is maximal outerplanar if the graph obtained by adding an edge is not outerplanar. Maximal outerplanar graphs are also known as triangulations of polygons. The spine of a maximal outerplanar graph G is the dual graph of G without the vertex that corresponds to the exterior region. In this thesis we study metric properties involving geodesic intervals, geodetic sets, Steiner sets, different concepts of boundary, and also relationships between the independence numbers and domination numbers …


The Burden Of Fetching Water: Using Caloric Expenditure As An Indicator Of Access To Safe Drinking Water—A Case Study From Xieng Khouang Province, Lao Pdr, Jeff La Frenierre Jun 2009

The Burden Of Fetching Water: Using Caloric Expenditure As An Indicator Of Access To Safe Drinking Water—A Case Study From Xieng Khouang Province, Lao Pdr, Jeff La Frenierre

Electronic Theses and Dissertations

The Millennium Development Goals measure ‘access to improved drinking water’ using an indicator that defines access as the presence of an improved water source within 1 kilometer of a person’s dwelling. This purely linear measurement has significant shortcomings, including a lack of consideration for the difficulty of the terrain being traversed and the weight of the loads being carried. This paper examines in detail the human energy costs associated with fetching water, first using two Lao villages as case studies, then applying a predictive energy expenditure model to measure the potential caloric effect of variations in the age and gender …


Routing In The Dark: Pitch Black, Nathan S. Evans Jun 2009

Routing In The Dark: Pitch Black, Nathan S. Evans

Electronic Theses and Dissertations

In many networks, such as mobile ad-hoc networks and friend-to-friend overlay networks, direct communication between nodes is limited to specific neighbors. Friendto-friend “darknet” networks have been shown to commonly have a small-world topology; while short paths exist between any pair of nodes in small-world networks, it is non-trivial to determine such paths with a distributed algorithm. Recently, Clarke and Sandberg proposed the first decentralized routing algorithm that achieves efficient routing in such small-world networks.

Herein this thesis we discuss the first independent security analysis of Clarke and Sandberg’s routing algorithm. We show that a relatively weak participating adversary can render …


Salamanders Of The Mio-Pliocene Gray Fossil Site, Washington County, Tennessee., Grant Stanley Boardman May 2009

Salamanders Of The Mio-Pliocene Gray Fossil Site, Washington County, Tennessee., Grant Stanley Boardman

Electronic Theses and Dissertations

Screening efforts at the Gray Fossil Site, Washington County, Tennessee, have yielded a unique and diverse salamander fauna for the southern Appalachian Mio-Pliocene; including at least five taxa from three modern families (Ambystomatidae, Plethodontidae, and Salamandridae) supporting the woodland-pond interpretation of the site. All specimens represent the earliest record of their respective families in the Appalachian Mountains; with the Notophthalmus sp. vertebrae being the only Mio-Pliocene skeletal fossil known for the family Salamandridae in North America. Three types of plethodontid salamander are present, with one type representing the earliest known desmognathine. The desmognathine fossils lend credence to the 'Appalachian' origin …


Decompositions Of Mixed Graphs With Partial Orientations Of The P4., Adam M. Meadows May 2009

Decompositions Of Mixed Graphs With Partial Orientations Of The P4., Adam M. Meadows

Electronic Theses and Dissertations

A decomposition D of a graph H by a graph G is a partition of the edge set of H such that the subgraph induced by the edges in each part of the partition is isomorphic to G. A mixed graph on V vertices is an ordered pair (V,C), where V is a set of vertices, |V| = v, and C is a set of ordered and unordered pairs, denoted (x, y) and [x, y] respectively, of elements of V [8]. An ordered pair (x …


Locating-Domination In Complementary Prisms., Kristin Renee Stone Holmes May 2009

Locating-Domination In Complementary Prisms., Kristin Renee Stone Holmes

Electronic Theses and Dissertations

Let G = (V (G), E(G)) be a graph and G̅ be the complement of G. The complementary prism of G, denoted GG̅, is the graph formed from the disjoint union of G and G̅ by adding the edges of a perfect matching between the corresponding vertices of G and G̅. A set D ⊆ V (G) is a locating-dominating set of G if for every u ∈ V (G)D, its neighborhood N(u)⋂D is nonempty and distinct from N( …


Cyclic, F-Cyclic, And Bicyclic Decompositions Of The Complete Graph Into The 4-Cycle With A Pendant Edge., Daniel Shelton Cantrell May 2009

Cyclic, F-Cyclic, And Bicyclic Decompositions Of The Complete Graph Into The 4-Cycle With A Pendant Edge., Daniel Shelton Cantrell

Electronic Theses and Dissertations

In this paper, we consider decompositions of the complete graph on v vertices into 4-cycles with a pendant edge. In part, we will consider decompositions which admit automorphisms consisting of:

(1) a single cycle of length v,

(2) f fixed points and a cycle of length v − f, or

(3) two disjoint cycles.

The purpose of this thesis is to give necessary and sufficient conditions for the existence of cyclic, f-cyclic, and bicyclic Q-decompositions of Kv.


Development Of A Reservoir Embayment Characterization Process To Prioritize Water Quality Improvement., Terry Shannon O'Quinn May 2009

Development Of A Reservoir Embayment Characterization Process To Prioritize Water Quality Improvement., Terry Shannon O'Quinn

Electronic Theses and Dissertations

To simplify water quality improvement in reservoirs, it has been suggested that efforts should be focused on smaller and more manageable units such as reservoir embayment areas. Embayments are prime locations to locate marinas, parks, beaches, and residential homes. Current data and information on reservoir embayments in Tennessee was assembled into a GIS-based database. Embayments of 11 main reservoirs were mapped and digitized in ArcGIS. Initial characterization criteria include watershed size, embayment area-watershed ratio, maximum residence time, and stream influence on embayments. The characterization process was then applied to the mapped reservoir embayments in Tennessee to identify and prioritize embayments …


Electrochemically Mediated Charge Transfer Effects On Single-Walled Carbon Nanotubes., Buddika Ka. Abeyweera 1980- May 2009

Electrochemically Mediated Charge Transfer Effects On Single-Walled Carbon Nanotubes., Buddika Ka. Abeyweera 1980-

Electronic Theses and Dissertations

This thesis is based on experimental work on electrochemically mediated charge transfer effects on Single-walled carbon nanotube bundles. The study of these effects are very important towards understanding the sensitivity of gases on nanostructures like single-walled carbon nanotubes. Chapter one covers the introduction and overview of carbon nanostructures including single-walled carbon nanotubes. Chapter two covers the experimental techniques involving sample preparation, experimental setup and data acquisition. Chapter three consists of Results and the Discussions explaining the mechanisms based on charge transfer mechanism. In the final chapter, implications and the importance of the study are explained. Single-walled carbon nanotubes are used …


Power Scaling Of Large Mode Area Thulium Fiber Lasers In Various Spectral And Temporal Regimes, Timothy Mccomb Jan 2009

Power Scaling Of Large Mode Area Thulium Fiber Lasers In Various Spectral And Temporal Regimes, Timothy Mccomb

Electronic Theses and Dissertations

High power thulium fiber lasers are interesting for a myriad of applications due to their potential for high average output power, excellent beam quality, compactness, portability, high operating efficiency and broad, eye-safe spectral range from 1.8-2.1 microns. Currently, the majority of thulium laser research effort is being invested into scaling average output powers; however, such output powers are being scaled with no degree of control on laser system output spectrum or temporal behavior. Thulium fiber laser technology is not useful for many of its most important applications without implementation of techniques enabling tunable, narrow spectral widths with appropriate pulse durations …


Development Of Novel Dart Tofms Analytical Techniques For The Identification Of Organic Contamination On Spaceflight-Related Substrates And Aqueous Media, Kathleen Loftin Jan 2009

Development Of Novel Dart Tofms Analytical Techniques For The Identification Of Organic Contamination On Spaceflight-Related Substrates And Aqueous Media, Kathleen Loftin

Electronic Theses and Dissertations

Organic contamination on spaceflight hardware is an ongoing concern for spaceflight safety. In addition, for the goal of analyzing for possible evidence of extra-terrestrial life, it is necessary to consider the presence of terrestrial contamination. This paper will introduce and evaluate a new method using a direct analysis real time (DART) ionization source paired with a high resolution time of flight mass spectrometer (TOFMS) for the determination of organic contamination involved in spaceflight hardware and ground support materials. This novel analytical technique has significant advantages over current methodologies. Materials analyzed in this study were historically considered as probable contaminants in …


Permutation Patterns, Reduced Decompositions With Few Repetitions And The Bruhat Order, Daniel Alan Daly Jan 2009

Permutation Patterns, Reduced Decompositions With Few Repetitions And The Bruhat Order, Daniel Alan Daly

Electronic Theses and Dissertations

This thesis is concerned with problems involving permutations. The main focus is on connections between permutation patterns and reduced decompositions with few repetitions. Connections between permutation patterns and reduced decompositions were first studied various mathematicians including Stanley, Billey and Tenner. In particular, they studied pattern avoidance conditions on reduced decompositions with no repeated elements. This thesis classifies the pattern avoidance and containment conditions on reduced decompositions with one and two elements repeated. This classification is then used to obtain new enumeration results for pattern classes related to the reduced decompositions and introduces the technique of counting pattern classes via reduced …


Heuristics For Improved Enterprise Intrusion Detection, James J. Treinen Jan 2009

Heuristics For Improved Enterprise Intrusion Detection, James J. Treinen

Electronic Theses and Dissertations

One of the greatest challenges facing network operators today is the identification of malicious activity on their networks. The current approach is to deploy a set of intrusion detection sensors (IDSs) in various locations throughout the network and on strategic hosts. Unfortunately, the available intrusion detection technologies generate an overwhelming volume of false alarms, making the task of identifying genuine attacks nearly impossible. This problem is very difficult to solve even in networks of nominal size. The task of uncovering attacks in enterprise class networks quickly becomes unmanageable.

Research on improving intrusion detection sensors is ongoing, but given the nature …


Analysis And Treatment Of Emerging Polar Contaminants, Daniel E. Connors Jan 2009

Analysis And Treatment Of Emerging Polar Contaminants, Daniel E. Connors

Electronic Theses and Dissertations

Two major classes of polar compounds have recently become a major focus as sources of contamination of water systems. Pharmaceuticals and personal care products (PPCPs) enter water through wastewater streams, and many of these compounds survive current wastewater treatment processes. High production volume chemicals (HPVCs), defined as chemicals produced in excess of one million pounds per year have numerous entries into surface and drinking waters due to their ubiquity. The commonality between many of these compounds is their polarity, which makes them water-soluble.

While both PPCPs and HPVCs have been entering into the environment for decades, advances in analyte detection …


Theoretical And Computational Studies Of Dissociative Recombination Of H3+ With Low Kinetic Energy Electrons: Time-Independent A, Samantha Santos Jan 2009

Theoretical And Computational Studies Of Dissociative Recombination Of H3+ With Low Kinetic Energy Electrons: Time-Independent A, Samantha Santos

Electronic Theses and Dissertations

Dissociative recombination of molecular ions by collisions with electrons is a reactive collision, in which the electronic kinetic energy is transferred to the excitation of the molecule that, then, dissociates. The goals of this dissertation was (1) to improve existing approaches in theory of DR of triatomic ions in the time-independent framework developed in recent years by Kokoouline and Greene, and (2) to develop a time-dependent theoretical framework for DR treatment based on quantum defect theory. The theoretical method developed by Kokoouline and Greene is based on multichannel quantum defect theory and accounts for the major non-Born-Oppenheimer Jahn-Teller interaction between …


Silicon Carbide And Agile Optics Based Sensors For Power Plant Gas Turbines, Laser Beam Analysis And Biomedicine, Mumtaz Sheikh Jan 2009

Silicon Carbide And Agile Optics Based Sensors For Power Plant Gas Turbines, Laser Beam Analysis And Biomedicine, Mumtaz Sheikh

Electronic Theses and Dissertations

Proposed are novel sensors for extreme environment power plants, laser beam analysis and biomedicine. A hybrid wireless-wired extreme environment temperature sensor using a thick single-crystal Silicon Carbide (SiC) chip embedded inside a sintered SiC probe design is investigated and experimentally demonstrated. The sensor probe employs the SiC chip as a Fabry-Perot (FP) interferometer to measure the change in refractive index and thickness of SiC with temperature. A novel temperature sensing method that combines wavelength-tuned signal processing for coarse measurements and classical FP etalon peak shift for fine measurements is proposed and demonstrated. This method gives direct unambiguous temperature measurements with …


Room Temperature Fluorescence Spectroscopy As A Tool For The Forensic Trace Analysis Of Textile Fibers, Matthew Rex Jan 2009

Room Temperature Fluorescence Spectroscopy As A Tool For The Forensic Trace Analysis Of Textile Fibers, Matthew Rex

Electronic Theses and Dissertations

Trace textile fiber evidence is found at numerous crime scenes and plays an important role in linking a suspect to the respective scene. Several methods currently exist for the analysis of trace fiber evidence. Microscopy provides information regarding the fibers material, color and weave. For more detailed chemical analysis chromatographic methods are employed and for discrimination between dyes, liquid chromatography coupled with mass spectrometry (LC-MS) is currently the method providing the most discrimination. These methods have primarily focused on the dyes used to color the fibers and have not investigated other components that can potentially discriminate among fibers. This dissertation …


Efficient Techniques For Relevance Feedback Processing In Content-Based Image Retrieval, Danzhou Liu Jan 2009

Efficient Techniques For Relevance Feedback Processing In Content-Based Image Retrieval, Danzhou Liu

Electronic Theses and Dissertations

In content-based image retrieval (CBIR) systems, there are two general types of search: target search and category search. Unlike queries in traditional database systems, users in most cases cannot specify an ideal query to retrieve the desired results for either target search or category search in multimedia database systems, and have to rely on iterative feedback to refine their query. Efficient evaluation of such iterative queries can be a challenge, especially when the multimedia database contains a large number of entries, and the search needs many iterations, and when the underlying distance measure is computationally expensive. The overall processing costs, …


Learning Semantic Features For Visual Recognition, Jingen Liu Jan 2009

Learning Semantic Features For Visual Recognition, Jingen Liu

Electronic Theses and Dissertations

Visual recognition (e.g., object, scene and action recognition) is an active area of research in computer vision due to its increasing number of real-world applications such as video (image) indexing and search, intelligent surveillance, human-machine interaction, robot navigation, etc. Effective modeling of the objects, scenes and actions is critical for visual recognition. Recently, bag of visual words (BoVW) representation, in which the image patches or video cuboids are quantized into visual words (i.e., mid-level features) based on their appearance similarity using clustering, has been widely and successfully explored. The advantages of this representation are: no explicit detection of objects or …


Realnav: Exploring Natural User Interfaces For Locomotion In Video Games, Brian Williamson Jan 2009

Realnav: Exploring Natural User Interfaces For Locomotion In Video Games, Brian Williamson

Electronic Theses and Dissertations

We present an exploration into realistic locomotion interfaces in video games using spatially convenient input hardware. In particular, we use Nintendo Wii Remotes to create natural mappings between user actions and their representation in a video game. Targeting American Football video games, we used the role of the quarterback as an exemplar since the game player needs to maneuver effectively in a small area, run down the field, and perform evasive gestures such as spinning, jumping, or the "juke". In our study, we developed three locomotion techniques. The first technique used a single Wii Remote, placed anywhere on the user's …


New Computational Approaches For Multiple Rna Alignment And Rna Search, Daniel Deblasio Jan 2009

New Computational Approaches For Multiple Rna Alignment And Rna Search, Daniel Deblasio

Electronic Theses and Dissertations

In this thesis we explore the the theory and history behind RNA alignment. Normal sequence alignments as studied by computer scientists can be completed in O(n2) time in the naive case. The process involves taking two input sequences and finding the list of edits that can transform one sequence into the other. This process is applied to biology in many forms, such as the creation of multiple alignments and the search of genomic sequences. When you take into account the RNA sequence structure the problem becomes even harder. Multiple RNA structure alignment is particularly challenging because covarying mutations make sequence …


Alliances In Graphs: Parameterized Algorithms And On Partitioning Series-Parallel Graphs, Rosa Enciso Jan 2009

Alliances In Graphs: Parameterized Algorithms And On Partitioning Series-Parallel Graphs, Rosa Enciso

Electronic Theses and Dissertations

Alliances are used to denote agreements between members of a group with similar interests. Alliances can occur between nations, biological sequences, business cartels, and other entities. The notion of alliances in graphs was first introduced by Kristiansen, Hedetniemi, and Hedetniemi in . A defensive alliance in a graph G = (V, E) is a non empty set S ⊆ V where, for all x ∈ S, |N[x] ∩ S| ≥ |N[x] − S|. Consequently, every vertex that is a member of a defensive alliance has at least as many vertices defending it as there are vertices attacking it. Alliances can …


On The Application Of Locality To Network Intrusion Detection: Working-Set Analysis Of Real And Synthetic Network Server Traffic, Robert Lee Jan 2009

On The Application Of Locality To Network Intrusion Detection: Working-Set Analysis Of Real And Synthetic Network Server Traffic, Robert Lee

Electronic Theses and Dissertations

Keeping computer networks safe from attack requires ever-increasing vigilance. Our work on applying locality to network intrusion detection is presented in this dissertation. Network servers that allow connections from both the internal network and the Internet are vulnerable to attack from all sides. Analysis of the behavior of incoming connections for properties of locality can be used to create a normal profile for such network servers. Intrusions can then be detected due to their abnormal behavior. Data was collected from a typical network server both under normal conditions and under specific attacks. Experiments show that connections to the server do …


Search And Delivery Techniques In Peer-To-Peer Networks, Tai Do Jan 2009

Search And Delivery Techniques In Peer-To-Peer Networks, Tai Do

Electronic Theses and Dissertations

The presence of millions of interconnected personal computing devices has given rise to a new class of decentralized networking applications, which are loosely labeled as peer-to-peer (P2P) applications. These P2P applications leverage resources such as processing cycles, storage, content, and network bandwidth available to the user devices, which are also known as peers. A number of current systems - SETI@home, Napster, BitTorrent, and Pastry - are examples of these emerging P2P systems. To fully realize the potential of the peer-to-peer technology, there is a need to define and provide a set of core competencies, serving as the basic services upon …


Connectionless Approach: A Localized Scheme To Mobile Ad Hoc Networks, Yao Ho Jan 2009

Connectionless Approach: A Localized Scheme To Mobile Ad Hoc Networks, Yao Ho

Electronic Theses and Dissertations

According to a Gartner Group (www.gartner.com) report in September 2008, the worldwide telecommunications market is on pace to reach $2 trillion in 2008. Gartner predicts that by 2012, the ratio of mobile to fixed connections will exceed 4-to-1. The North American mobile data market grew to 141.1 million connections in 2007, with a compound annual growth rate of 41.7 percent. It is believed that a large portion will be ad hoc and multi-hop connections, which will open many opportunities for Mobile Ad hoc NETwork (MANET) applications and Wireless Mesh Network (WMN) applications. A MANET is a self-organizing multi-hop wireless network …


Learning Techniques For Information Retrieval And Mining In High-Dimensional Databases, Hao Cheng Jan 2009

Learning Techniques For Information Retrieval And Mining In High-Dimensional Databases, Hao Cheng

Electronic Theses and Dissertations

The main focus of my research is to design effective learning techniques for information retrieval and mining in high-dimensional databases. There are two main aspects in the retrieval and mining research: accuracy and efficiency. The accuracy problem is how to return results which can better match the ground truth, and the efficiency problem is how to evaluate users' requests and execute learning algorithms as fast as possible. However, these problems are non-trivial because of the complexity of the high-level semantic concepts, the heterogeneous natures of the feature space, the high dimensionality of data representations and the size of the databases. …


The Biochemical Reactions Of Dry State Dna, April Marrone Jan 2009

The Biochemical Reactions Of Dry State Dna, April Marrone

Electronic Theses and Dissertations

The biochemistry of dry state DNA is of interest to the fields of forensics, ancient DNA, and DNA storage. The exact chemical nature of the degradation of the DNA molecule in the dry state has not been studied prior. If determined what chemical changes the DNA molecule undergoes, to what degree and in what time frame then protocols can be implemented to bypass the impact of this damage or to repair it when necessary. It is suspected that similar reactions occur to the dry state DNA molecule as does to the hydrated molecule. It cannot be assumed, however that these …


Water And The Mountains: Maya Water Mangement At Caracol, Belize, James Crandall Jan 2009

Water And The Mountains: Maya Water Mangement At Caracol, Belize, James Crandall

Electronic Theses and Dissertations

Water management techniques in the Southern Maya Lowlands are both regionally diverse and site specific. This thesis examines the water management strategies of the Classic Period Maya at the site of Caracol, Belize. While it is likely that elites at Caracol controlled the redistribution of resources, i.e. craft and agricultural products, it is probable that the production of agricultural resources and the maintenance of water resource acquisition took place on a more local level. In order to test this hypothesis, a sample of five reservoirs were examined through original research -- and situated in conjunction with past settlement studies -- …


Application Of Alkylsilane Self-Assembled Monolayers For Cell Patterning And Development Of Biolocial Microelectromechanical Systems, Kerry Wilson Jan 2009

Application Of Alkylsilane Self-Assembled Monolayers For Cell Patterning And Development Of Biolocial Microelectromechanical Systems, Kerry Wilson

Electronic Theses and Dissertations

Advances in microfabrication and surface chemistry techniques have provided a new paradigm for the creation of in vitro systems for studying problems in biology and medicine in ways that were previously not practical. The ability to create devices with micro- to nano-scale dimensions provides the opportunity to non-invasively interrogate and monitor biological cells and tissue in large arrays and in a high-throughput manner. These systems hold the potential to, in time, revolutionize the way problems in biology and medicine are studied in the form of point-of-care devices, lab-on-chip devices, and biological microelectromechanical systems (BioMEMS). With new in vitro models, it …


Nanofiltration Membrane Pilot Studies For Disinfection By-Product Control, Eric J. Lynne Jan 2009

Nanofiltration Membrane Pilot Studies For Disinfection By-Product Control, Eric J. Lynne

Electronic Theses and Dissertations

Watertown, South Dakota currently uses conventional softening to treat ground water to remove hardness, iron and manganese, and natural organic matter. The distribution system has experienced elevated concentrations of disinfection by-products, which will require additional treatment to comply with future limits set by the Stage 2 Disinfectant/Disinfection By-Products Rule. A nanofiltration membrane system has been proposed to remove additional natural organic matter from the softened water. Removing the natural organic material disinfection by-product precursors should reduce the concentration of disinfection by-products. The use of nanofiltration membranes has been previously documented to reject total organic carbon, while allowing desirable levels of …