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Articles 4201 - 4230 of 5954

Full-Text Articles in Physical Sciences and Mathematics

Neighborhood Defined Adaboost Based Mixture Of Color Components For Efficient Skin Segmentation, Ramya Reddy Maaram Oct 2007

Neighborhood Defined Adaboost Based Mixture Of Color Components For Efficient Skin Segmentation, Ramya Reddy Maaram

Electrical & Computer Engineering Theses & Dissertations

A skin segmentation algorithm robust to illumination changes and skin-like backgrounds is developed in this thesis. So far skin pixel classification has been limited to only individual color spaces and there has not been a comprehensive evaluation of which color components or combination of color components would provide the best classification accuracy, Color components in a given color space form the feature set for the classification of skin pixels. The combination of the color components or the features present within a single color space may not be the best when it comes to skin pixel classification as the discriminatory power …


A Robust Method For Multiple Face Tracking Using Kalman Filter, Zaheer Shaik Oct 2007

A Robust Method For Multiple Face Tracking Using Kalman Filter, Zaheer Shaik

Electrical & Computer Engineering Theses & Dissertations

A robust method for tracking faces of multiple people moving in a scene using a Kalman filter is proposed. This method overcomes the problem of partial and total occlusion for a short period. The method uses a combination of face detection and cloth matching to track and differentiate between people. A Template matching technique for face and a non-parametric distribution for cloth are used. Face templates are obtained from the first frame of a video sequence by applying the Viola-Jones face detection method. Cloth color distribution is obtained from people's clothes, assuming that the bodies move along with the faces. …


A Modular Kernel Linear Discriminant Analysis Of Gabor Features For Improved Face Recognition, Neeharika Gudur Oct 2007

A Modular Kernel Linear Discriminant Analysis Of Gabor Features For Improved Face Recognition, Neeharika Gudur

Electrical & Computer Engineering Theses & Dissertations

Automatic face recognition is one of the major challenges in computer vision and pattern analysis. This thesis presents an efficient face recognition system that is robust with regards to changes in illumination, facial expressions and partial occlusions. Modular Kernel Linear Discriminant Analysis performed on Gabor Features obtained from the face images is employed for improving face recognition accuracy. A face image is pre-processed using the 2D Gabor wavelet transform to achieve invariance to illumination in images. Modular approaches that divide the pre-processed images into smaller sub-images provide improved accuracy, as the facial variations in an image are confined to local …


Self-Organization In Cathode Boundary Layer Discharges, Nobuhiko Takano Oct 2007

Self-Organization In Cathode Boundary Layer Discharges, Nobuhiko Takano

Electrical & Computer Engineering Theses & Dissertations

Cathode boundary layer (CBL) discharge, which has been developed as a UV light source, operates in a direct current between a planar cathode and a ring-shape anode that are separated by a dielectric with an opening of the same diameter as the anode. The nonthermal CBL discharges operate in a medium pressure range down to 30 Torr, emitting excimer radiation when operated with noble gases. The radiant excimer emittance at 172 nm in xenon reaches 1.7 W/cm2, and a maximum excimer efficiency of 6 % has been obtained. The high excimer radiant emittance, in addition to low cost …


Integrating Game Technology And Discrete Event Simulation To Analyze Mass Casualty Scenarios, Jason Loveland Oct 2007

Integrating Game Technology And Discrete Event Simulation To Analyze Mass Casualty Scenarios, Jason Loveland

Computational Modeling & Simulation Engineering Theses & Dissertations

In the last 10 years, video games have become complex simulation environments with high resolution 3D graphics enabled by powerhouse rendering engines, multi-player client server networks, user friendly displays and graphical user interface , while remaining relatively inexpensive. There is a critical need for systems engineering analysis and rapid trade studies due to changes in operations caused by current events such as terrorist attacks, asymmetric threats, natural disasters, etc. Modem games provide a unique way to visualize and interact with these complex environments, scenarios, missions, and operations. A discrete event simulator (DES) provides an environment to model system architecture behavior, …


Channel Management In Heterogeneous Cellular Networks, Mohammad Hadi Arbabi Aug 2007

Channel Management In Heterogeneous Cellular Networks, Mohammad Hadi Arbabi

Computer Science Theses & Dissertations

Motivated by the need to increase system capacity in the face of tight FCC regulations, modem cellular systems are under constant pressure to increase the sharing of the frequency spectrum among the users of the network.

Key to increasing system capacity is an efficient channel management strategy that provides higher capacity for the system while, at the same time, providing the users with Quality of Service guarantees. Not surprisingly, dynamic channel management has become a high profile topic in wireless communications. Consider a highly populated urban area, where mobile traffic loads are increased due to highway backups or sporting events. …


Circulation, Vol. 14, No. 1, Center For Coastal Physical Oceanography, Old Dominion University, Brian Ward Jul 2007

Circulation, Vol. 14, No. 1, Center For Coastal Physical Oceanography, Old Dominion University, Brian Ward

CCPO Circulation

Summer 2007 issue of CCPO Circulation featuring article "Air-Sea Measurements in the Indian Ocean" by Dr. Brian Ward


Virginia Junior Academy Of Science Awards, 2007 Jul 2007

Virginia Junior Academy Of Science Awards, 2007

Virginia Journal of Science

Virginia Junior Academy of Science Awards Presented During the 66th Annual Meeting at James Madison University, Harrisonburg, Virginia, May 23-25, 2007.


Abstracts Of Papers, 85th Annual Meeting Of The Virginia Academy Of Science, May 24-26, 2007, James Madison University, Harrisonburg Va Jul 2007

Abstracts Of Papers, 85th Annual Meeting Of The Virginia Academy Of Science, May 24-26, 2007, James Madison University, Harrisonburg Va

Virginia Journal of Science

Full abstracts of the 85th Annual Meeting of the Virginia Academy of Science, May 24-26, 2007, James Madison University, Harrisonburg VA


Annual And Interannual Variability In The Wind Field And The Hydrography Along The Seward Line In The Northern Gulf Of Alaska, Isaac Schroeder Jul 2007

Annual And Interannual Variability In The Wind Field And The Hydrography Along The Seward Line In The Northern Gulf Of Alaska, Isaac Schroeder

OES Theses and Dissertations

The Northeast Pacific GLOBEC (GLOBal ocean Ecosystems dynamics) program (October 1997 to December 2004) collected hydrographic data along the Seward Line that stretches from the inner shelf (GAM 59.8°N, 149.5°W) and extends over 200 km beyond the continental slope (GAK13 58.1°N, 147.8°W). The complexity of the interannual hydrographic variability in this area stems from the interacting influences of local forcing such as winds, coastal freshwater discharge, eddies, fronts and remote forcing like El Niño-Southern Oscillation. Until now, the influence of winds on the system has been calculated using coarse resolution upwelling index data or spatially sparse buoy data. The coarse …


Investigating Real-Time Sonar Performance Predictions Using Beowulf Clustering, Charles Lane Cartledge Jul 2007

Investigating Real-Time Sonar Performance Predictions Using Beowulf Clustering, Charles Lane Cartledge

Computer Science Theses & Dissertations

Predicting sonar performance, critical to using any sonar to its maximum effectiveness, is computationally intensive and typically the results are based on data from the past and may not be applicable to the current water conditions. This paper discusses how Beowulf clustering techniques were investigated and applied to achieve real-time sonar performance prediction capabilities based on commercially off the shelf (COTS) hardware and software. A sonar system measures ambient noise in real-time. Based on the active sonar range scale, new ambient measurements can be available every 1 to 24 seconds. Traditional sonar performance prediction techniques operated serially and often took …


Distributed Knowledge Discovery In Large Scale Peer-To-Peer Networks, Sachin Shetty Jul 2007

Distributed Knowledge Discovery In Large Scale Peer-To-Peer Networks, Sachin Shetty

Computational Modeling & Simulation Engineering Theses & Dissertations

Explosive growth in the availability of various kinds of data in distributed locations has resulted in unprecedented opportunity to develop distributed knowledge discovery (DKD) techniques. DKD embraces the growing trend of merging computation with communication by performing distributed data analysis and modeling with minimal communication of data. Most of the current state-of-the-art DKD systems suffer from the lack of scalability, robustness and adaptability due to their dependence on a centralized model for building the knowledge discovery model. Peer-to-Peer networks offer a better scalable and fault-tolerant computing platform for building distributed knowledge discovery models than client-server based platforms. Algorithms and communication …


Mixed Layer Dynamics Along The Seward Line In The Northern Gulf Of Alaska, Nandita Sarkar Jul 2007

Mixed Layer Dynamics Along The Seward Line In The Northern Gulf Of Alaska, Nandita Sarkar

OES Theses and Dissertations

The northern Gulf of Alaska marine ecosystem is very productive with a "nutrient paradox". Primary producers require light and nutrients for photosynthesis. A primary source of nutrients is the deep ocean, while light is available in a relatively shallow layer in the upper ocean. In most productive parts of the world oceans, nutrients are brought to surface waters by upwelling. However, in the northern Gulf of Alaska, the winds are generally downwelling inducing and the mechanism(s) by which nutrients are brought to the euphotic zone are not known. One mechanism that might bring nutrients into the euphotic zone is the …


Cave Development In Strata Of Ordovician-And Silurian-Devonian-Age In Highland County, Virginia, Carol Ann Peterson Jul 2007

Cave Development In Strata Of Ordovician-And Silurian-Devonian-Age In Highland County, Virginia, Carol Ann Peterson

OES Theses and Dissertations

Picturesque Highland County, Virginia, also known as "Virginia's Little Switzerland", is characterized by high mountains, tranquil rivers, and hundreds of caves. This study determines how geologic structures and processes control speleogenesis, or cave development, in the county. Solutional caves in Highland County are found in Ordovician limestones and dolostones and in Silurian- to Devonian-age limestones. Despite the lithologic and structural differences between the strata, caves in both sections tend to be similarly joint-controlled in directions of both regional strike (N40°E), dip (northwest or southeast), or in fractures intersecting at 60 and/or 120 degrees. Brittle failure, including fractures and faults induced …


On The Use Of Quasi-Newton Methods For The Minimization Of Convex Quadratic Splines, William Howard Thomas Ii Jul 2007

On The Use Of Quasi-Newton Methods For The Minimization Of Convex Quadratic Splines, William Howard Thomas Ii

Mathematics & Statistics Theses & Dissertations

In reformulating a strictly convex quadratic program with simple bound constraints as the unconstrained minimization of a strictly convex quadratic spline, established algorithms can be implemented with relaxed differentiability conditions. In this work, the positive definite secant update method of Broyden, Fletcher, Goldfarb, and Shanno (BFGS) is investigated as a tool to solve the unconstrained minimization problem. It is shown that there is a linear convergence rate and, for nondegenerate problems, the process terminates in a finite number of iterations. Numerical examples are provided.


Condensed And Expanded Sections In The Lower Mesaverde Clastic Wedge, Campanian Of Wyoming: Evidence For Tectonic Rectification Of Sea Level, Matthew W. Botzler Jul 2007

Condensed And Expanded Sections In The Lower Mesaverde Clastic Wedge, Campanian Of Wyoming: Evidence For Tectonic Rectification Of Sea Level, Matthew W. Botzler

OES Theses and Dissertations

The stratigraphy of the Cretaceous Western Interior basin indicates that sea level oscillated during the late Cretaceous. The oscillations were polyharmonic, with periods ranging from millions of years to hundred thousands and ten thousands of years. However, there is disagreement over the extent to which sea level change was global in nature and the extent to which it was driven by local uplift or subsidence (tectonism). In orogenic regions where subsidence, sediment supply, and eustatic variation are all affecting sea level, comparisons of high and low frequency cycles can help to sort out forcing mechanisms. Low frequency eustatic sea level …


2007 Vas Meeting Best Student Papers Jul 2007

2007 Vas Meeting Best Student Papers

Virginia Journal of Science

List of award winning student papers by section from the 85th Annual Meeting of the Virginia Academy of Science, May 24-26, 2007, James Madison University, Harrisonburg, VA


Factors Affecting Website Reconstruction From The Web Infrastructure, Frank Mccown, Norou Diawara, Michael L. Nelson Jun 2007

Factors Affecting Website Reconstruction From The Web Infrastructure, Frank Mccown, Norou Diawara, Michael L. Nelson

Computer Science Faculty Publications

When a website is suddenly lost without a backup, it may be reconstituted by probing web archives and search engine caches for missing content. In this paper we describe an experiment where we crawled and reconstructed 300 randomly selected websites on a weekly basis for 14 weeks. The reconstructions were performed using our web-repository crawler named Warrick which recovers missing resources from the Web Infrastructure (WI), the collective preservation effort of web archives and search engine caches. We examine several characteristics of the websites over time including birth rate, decay and age of resources. We evaluate the reconstructions when compared …


The Sensitivity Of The Southwest Monsoon Phytoplankton Bloom To Variations In Aeolian Iron Deposition Over The Arabian Sea, Jerry D. Wiggert, Raghu G. Murtugudde May 2007

The Sensitivity Of The Southwest Monsoon Phytoplankton Bloom To Variations In Aeolian Iron Deposition Over The Arabian Sea, Jerry D. Wiggert, Raghu G. Murtugudde

CCPO Publications

[1] A coupled, 3-D biophysical ocean general circulation model is used to investigate how aeolian iron deposition affects the Arabian Sea ecosystem. Two separate aeolian iron deposition fields, derived from the GISS and GOCART atmospheric transport models, have been applied as surface boundary conditions. The model results exhibit widespread biogeochemical sensitivity to the choice of deposition field. With GOCART deposition, SW Monsoon phytoplankton blooms in the western and central Arabian Sea are enhanced and exhibit greater realism. The central Arabian Sea bloom is supported by supplemental input of horizontally advected iron from a pool that undergoes a yearlong progression that …


The Open Archives Initiative, Michael L. Nelson May 2007

The Open Archives Initiative, Michael L. Nelson

Computer Science Presentations

PDF of a powerpoint presentation from the Open Archives Initiative DRIADE ( Digital Repository of Information and Data for Evolution) Workshop, Durham, North Carolina, May 16-17, 2007. Also available on Slideshare.


Jeffress Research Grant - 2005 Apr 2007

Jeffress Research Grant - 2005

Virginia Journal of Science

Seven-page list of winners of the Jeffress Research Grant Awards for 2005.


Jeffress Research Grant Awards - 2006 Apr 2007

Jeffress Research Grant Awards - 2006

Virginia Journal of Science

List of winners of the Jeffress Research Grant Awards for 2006.


An Isotropic Metric, Joseph D. Rudmin Apr 2007

An Isotropic Metric, Joseph D. Rudmin

Virginia Journal of Science

An isotropic metric for a black hole and a better vacuum condition \nabla^2 V_G =0 are presented which yield distinct terms for the energy densities of ordinary matter and gravitational fields in the Einstein tensor (G^44 =-g^2 (2\nabla^2 V_G +(\nabla V_G)^2)). This model resolves an inconsistency between electromagnetism and gravity in the calculation of field energy. Resolution of this inconsistency suggests a slight modification of the Einstein equation to gG^\mu\nu = 8\pi G T^\mu\nu.


Diagnosing Reading Strategies: Paraphrase Recognition, Chutima Boonthum Apr 2007

Diagnosing Reading Strategies: Paraphrase Recognition, Chutima Boonthum

Computer Science Theses & Dissertations

Paraphrase recognition is a form of natural language processing used in tutoring, question answering, and information retrieval systems. The context of the present work is an automated reading strategy trainer called iSTART (Interactive Strategy Trainer for Active Reading and Thinking). The ability to recognize the use of paraphrase—a complete, partial, or inaccurate paraphrase; with or without extra information—in the student's input is essential if the trainer is to give appropriate feedback. I analyzed the most common patterns of paraphrase and developed a means of representing the semantic structure of sentences. Paraphrases are recognized by transforming sentences into this representation and …


The Observation, Modeling, And Retrieval Of Bio-Optical Properties For Coastal Waters Of The Southern Chesapeake Bay, Xiaoju Pan Apr 2007

The Observation, Modeling, And Retrieval Of Bio-Optical Properties For Coastal Waters Of The Southern Chesapeake Bay, Xiaoju Pan

OES Theses and Dissertations

The primary purpose of this study was to develop an inverse method to retrieve the inherent optical properties (IOPs) and biogeochemical parameters (e.g. chlorophyll a concentration and salinity) appropriate to monitor the water quality and biogeochemical processes from remote sensing of the coastal waters in the southern Chesapeake Bay and coastal Mid-Atlantic Bight region (MAB) dominated by Case 2 waters. For this purpose, knowledge of the relationship between remote sensing reflectance (Rrs) and IOPs and the effect from bottom reflectance on Rrs, is required.

A substantial investigation of IOPs has been conducted for the coastal …


Effects Of Elevated Atmospheric Co2 On Root Dynamics, Biomass And Architecture In A Scrub-Oak Ecosystem At Kennedy Space Center, Florida, Daniel Benjamin Stover Apr 2007

Effects Of Elevated Atmospheric Co2 On Root Dynamics, Biomass And Architecture In A Scrub-Oak Ecosystem At Kennedy Space Center, Florida, Daniel Benjamin Stover

Biological Sciences Theses & Dissertations

A major gap in whole-plant ecology lies with our understanding of root system growth, function and distribution. Large belowground structures, in addition to fine roots, are of particular interest because of their role in carbon sequestration. Non-destructive methods, including ground-penetrating radar (GPR) and minirhizotron observation tubes, were used to investigate effects of elevated CO2 on root biomass, dynamics (productivity, mortality, and turnover), root persistence and architecture in a fire dominated scrub-oak ecosystem. Open-top chambers have been exposed to elevated atmospheric CO2 for the past eleven years at Kennedy Space Center, Florida. No significant sustained CO2 treatment effects …


Long-Range Target Classification In A Cluttered Environment Using Multi-Sensor Image Sequences, Cenk Yaman Apr 2007

Long-Range Target Classification In A Cluttered Environment Using Multi-Sensor Image Sequences, Cenk Yaman

Electrical & Computer Engineering Theses & Dissertations

Accurate identification of unknown contacts is crucial in military intelligence. Automated systems which quickly and accurately determine the identity of a contact could be a benefit in backing up electronic signal identification methods such as Identification Friend and Foe (IFF) systems. Radio Detection and Ranging (RADAR) images are often undesirable in military applications since they reveal the location of the imaging system. So we explore the use of visible and infrared images of which are generally more consistent than RADAR images and for which it is easy to compensate for environmental effects. Recent advances in visible and IR imaging technology …


Interactions Between Phytoplankton And Bacteria In The Uptake Of Organic Compounds, Andrea Michel Rocha Apr 2007

Interactions Between Phytoplankton And Bacteria In The Uptake Of Organic Compounds, Andrea Michel Rocha

OES Theses and Dissertations

The most common methods for estimating bacterial productivity are [3H]-leucine and [3H]-thymidine incorporation. Uptake of these compounds has been attributed primarily to bacteria; however, because dissolved organic nitrogen may be an important N source for some phytoplankton, the use of these compounds to estimate bacterial productivity needs to be reexamined. In order to ascertain whether phytoplankton could compete with bacteria on relevant timescales and thereby bias bacterial productivity estimates in estuaries, I examined the ability of cultured phytoplankton and size-fractionated natural populations to take up leucine and thymidine in systems seasonally dominated by phytoplankton mixotrophs. In …


Measurements Of Correlated Pair Momentum Distributions In -3he(E,E',P,P)N With Clas, Hovhannes Baghdasaryan Apr 2007

Measurements Of Correlated Pair Momentum Distributions In -3he(E,E',P,P)N With Clas, Hovhannes Baghdasaryan

Physics Theses & Dissertations

Nucleon-Nucleon (NN) Short Range Correlations (SRC) represent a valuable part of the nuclear wave function. Improved knowledge of SRC will give us a better understanding of nuclear matter and nuclear interactions in extreme conditions. A study of the effects of short-range correlations using the 3He(e, e'pp)n reaction measured at Jefferson Lab is presented. Two different approaches were selected to investigate SRC. The first approach consists of the kinematics when we investigate the two active protons and neutron is the spectator (was not involved in the interaction). This kinematics dominates by Final State Interactions which are reasonably …


A Technique For Solving The Singular Integral Equations Of Potential Theory, Brian George Burns Apr 2007

A Technique For Solving The Singular Integral Equations Of Potential Theory, Brian George Burns

Mathematics & Statistics Theses & Dissertations

The singular integral equations of Potential Theory are investigated using ideas from both classical and contemporary mathematics. The goal of this semi-analytic approach is to produce numerical schemes that are both general and computationally simple. Previous works based on classical methods have yielded solutions only for very special cases while contemporary methods such as finite differences, finite elements and boundary element techniques are computationally extensive. Since the two-dimensional integral equations of interest exhibit structural invariance under a wide class of conformal mappings initial emphasis is placed on circular domains. By Fourier expansion with respect to the angular variable, such two-dimensional …