Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2003

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 3001 - 3030 of 3354

Full-Text Articles in Physical Sciences and Mathematics

Music, Cbf And Differential Algebraic Constant Modulus Algorithms For Direction Of Arrival Estimation In Passive Coherent Locators, Ahmet Özçeti̇n Jan 2003

Music, Cbf And Differential Algebraic Constant Modulus Algorithms For Direction Of Arrival Estimation In Passive Coherent Locators, Ahmet Özçeti̇n

Turkish Journal of Electrical Engineering and Computer Sciences

In passive coherent locators (PCL) systems, noise and the precision of direction of arrival (DOA) estimation are key issues. This paper addresses the implementation of high-resolution DOA estimation methods, in particular the multiple signal classification (MUSIC) algorithm, the conventional beam forming (CBF) algorithm, and the algebraic constant modulus algorithm (ACMA). The goal is to compare the ACMA to the MUSIC and CBF algorithms for application to PCL. The results and analysis presented here support the use of constant modulus information, where available, as an important addition to DOA estimation. The ACMA offers many simple solutions to noise and separation related …

Go to article

Sand Creek Watershed Project / Sand Creek Watershed Management Plan, Annis Water Research Institute Jan 2003

Sand Creek Watershed Project / Sand Creek Watershed Management Plan, Annis Water Research Institute

Watershed Management Plans and Reports

The overall goal of the Sand Creek Watershed Project is to improve and protect the designated uses of the watershed. In order to achieve this overall goal and attain compliance with the TMDL established in Sand Creek, four goals have been established and prioritized. The primary goal of the Sand Creek Watershed Project is to restore or improve the cold water fishery. The secondary goal of the project is to protect and improve the habitats of native aquatic life and wildlife. Both goals can be achieved by reducing the amount of known pollutants affecting both of these uses. Pollutant reduction …

Go to article

Water Resources Year In Review - Winter 2003, Annis Water Resource Institute Jan 2003

Water Resources Year In Review - Winter 2003, Annis Water Resource Institute

AWRI Reviews

No abstract provided.

Go to article

Coherent Backscattering Of Light In Atomic Systems: Application To Weak Localization In An Ensemble Of Cold Alkali-Metal Atoms, D. V. Kupriyanov, I. M. Sokolov, P. Kulatunga, C. I. Sukenik, M. D. Havey Jan 2003

Coherent Backscattering Of Light In Atomic Systems: Application To Weak Localization In An Ensemble Of Cold Alkali-Metal Atoms, D. V. Kupriyanov, I. M. Sokolov, P. Kulatunga, C. I. Sukenik, M. D. Havey

Physics Faculty Publications

Development of a theoretical treatment of multiple coherent light scattering in an ultracold atomic gas is reported. Specific application is made to coherent backscattering of a weak-radiation field from realistically modeled samples of ultracold atomic 85Rb. Comprehensive Monte Carlo simulations of the spatial, spectral, and polarization dependence of the backscattering line shape are made and compared with available experimental results.

Go to article

The Neutron Charge Form Factor And Target Analyzing Powers From 3He (E→, E 'N) Scattering, J. Bermuth, P. Merle, C. Carasco, D. Baumann, R. Böhm, D. Bosnar, M. Ding, M. O. Distler, J. Friedrich, A. Klein Jan 2003

The Neutron Charge Form Factor And Target Analyzing Powers From 3He (E→, E 'N) Scattering, J. Bermuth, P. Merle, C. Carasco, D. Baumann, R. Böhm, D. Bosnar, M. Ding, M. O. Distler, J. Friedrich, A. Klein

Physics Faculty Publications

The charge form factor of the neutron has been determined from asymmetries measured in quasi-elastic 3He(e→, e 'n) at a momentum transfer of 0.67 (GeV/c)2. In addition, the target analyzing power, Ayo has been measured to study effects of final state interactions and mespn exchange currents.

Go to article

First Measurement Of Transferred Polarization In The Exclusive →E P → E'K+ →Λ, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, J. Yun Jan 2003

First Measurement Of Transferred Polarization In The Exclusive →E P → E'K+ →Λ, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, J. Yun

Physics Faculty Publications

The first measurements of the transferred polarization for the exclusive →ep → e'K+ →Λ over right arrow reaction have been performed at Jefferson Laboratory using the CLAS spectrometer. A 2.567 GeV beam was used to measure the hyperon polarization over Q2 from 0.3 to 1.5 (GeV/c)2, W from 1.6 to 2.15 GeV, and over the full K+ center-of-mass angular range. Comparison with predictions of hadrodynamic models indicates strong sensitivity to the underlying resonance contributions. A nonrelativistic quark-model interpretation of our data suggests that the s -s quark pair is produced with spins predominantly …

Go to article

Measurement Of Inclusive Spin Structure Functions Of The Deuteron, J. Yun, S. E. Kuhn, G. E. Dodge, T. A. Forest, M. Bektasoglu, L. Ciciani, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, L. M. Qin, S. Stepanyan, L. B. Weinstein, Et Al., Clas Collaboration Jan 2003

Measurement Of Inclusive Spin Structure Functions Of The Deuteron, J. Yun, S. E. Kuhn, G. E. Dodge, T. A. Forest, M. Bektasoglu, L. Ciciani, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, L. M. Qin, S. Stepanyan, L. B. Weinstein, Et Al., Clas Collaboration

Physics Faculty Publications

We report the results of a new measurement of spin structure functions of the deuteron in the region of moderate momentum transfer [Q2 = 0.27-1.3 (GeV/c)2] and final hadronic state mass in the nucleon resonance region (W=1.08-2.0 GeV). We scattered a 2.5 GeV polarized continuous electron beam at Jefferson Lab off a dynamically polarized cryogenic solid state target (15ND3) and detected the scattered electrons with the CEBAF large acceptance spectrometer. From our data, we extract the longitudinal double spin asymmetry A∥ and the spin structure function g1d. Our data are …

Go to article

Iron-Mediated Preparation Of Vinylcyclopropanes. Scope, Mechanism, And Applications, Young K. Yun, Kamil Godula, Yeyu Cao, William A. Donaldson Jan 2003

Iron-Mediated Preparation Of Vinylcyclopropanes. Scope, Mechanism, And Applications, Young K. Yun, Kamil Godula, Yeyu Cao, William A. Donaldson

Chemistry Faculty Research and Publications

The addition of stabilized carbon nucleophiles to tricarbonyl(1-methoxycarbonylpentadienyl)iron(1+) cation (1a) proceeds via attack at C2 on the face of the ligand opposite the Fe(CO)3 group to generate tricarbonyl(pentenediyl)iron complexes 2. Oxidation of complexes 2 affords vinylcyclopropanecarboxylates in good yield. In general, the relative stereochemistry about the cyclopropane ring reflects reductive elimination with retention of configuration. In cases where the C2 substituent is bulky (i.e., 2b) the major cyclopropane product 9b represents ring closure with inversion at C3. A mechanism involving π−σ−π rearrangement of the initially oxidized (pentenediyl)iron species is proposed to account for these results. …

Go to article

An Xps Investigation Of Thermal Degradation And Charring On Poly(Vinyl Chloride)–Clay Nanocomposites, Jianxin Du, Dongyan Wang, Charles A. Wilkie, Jiangqi Wang Jan 2003

An Xps Investigation Of Thermal Degradation And Charring On Poly(Vinyl Chloride)–Clay Nanocomposites, Jianxin Du, Dongyan Wang, Charles A. Wilkie, Jiangqi Wang

Chemistry Faculty Research and Publications

More information concerning the thermal degradation and charring of nanocomposites of poly(vinyl chloride), dioctyl phthalate and clay has been obtained by the use of X-ray photoelectron spectroscopy and the acquisition of the carbon (C1s), chlorine (Cl2p), and oxygen (O1s) spectra. In the cases of polystyrene–clay and poly(methyl methacrylate)–clay nanocomposites, it has been shown that the clay migrates to the surface as the temperature is raised and the polymer degrades, thereby confirming the barrier properties as a mechanism by which these materials function. For PVC–clay nanocomposites the surface at high temperatures is dominated by carbon, and not the oxygen of the …

Go to article

Preparation And Flammability Properties Of Polyethylene-Clay Nanocomposites, Jinguo Zhang, Charles A. Wilkie Jan 2003

Preparation And Flammability Properties Of Polyethylene-Clay Nanocomposites, Jinguo Zhang, Charles A. Wilkie

Chemistry Faculty Research and Publications

Polyethylene (PE)–clay nanocomposites have been prepared using melt blending in a Brabrender mixer. X-ray diffraction and transmission electron microscopy were used to characterize the nano-structure of these composites while the thermal stability was evaluated from thermogravimetric analysis and the flammability parameters using cone calorimetry. It is found that the PE–clay nanocomposites have a mixed immiscible-intercalated structure and there is better intercalation when maleic anhydride is combined with the polymer and clay to be melt blended. The reduction in peak heat release rate is 30–40%.

Go to article

Flame Retardancy Of Polystyrene Nanocomposites Based On An Oligomeric Organically-Modified Clay Containing Phosphate, Xiaoxia Zheng, Charles A. Wilkie Jan 2003

Flame Retardancy Of Polystyrene Nanocomposites Based On An Oligomeric Organically-Modified Clay Containing Phosphate, Xiaoxia Zheng, Charles A. Wilkie

Chemistry Faculty Research and Publications

Novel modified clays, which may enable the formation of flame retarded polystyrene nanocomposites by melt or solution blending, have been prepared using an ammonium salt which contains an oligomeric material consisting of vinylbenzyl chloride, styrene and vinyl phosphate reacting with dimethylhexadecylamine. These nanocomposites have been characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, cone calorimetry and the evaluation of mechanical properties. Melt blending is an effective, economical way to produce intercalated nanocomposites with greatly reduced peak heat release rate and a decreased total heat release; the polymer does not all undergo thermal degradation.

Go to article

Synergy Between Conventional Phosphorus Fire Retardants And Organically-Modified Clays Can Lead To Fire Retardancy Of Styrenics, Grace Chigwada, Charles A. Wilkie Jan 2003

Synergy Between Conventional Phosphorus Fire Retardants And Organically-Modified Clays Can Lead To Fire Retardancy Of Styrenics, Grace Chigwada, Charles A. Wilkie

Chemistry Faculty Research and Publications

Polystyrene–clay nanocomposites combined with phosphorous-containing fire retardants have been prepared and used to explore the thermal stability and mechanical properties of the polymer formed. The amounts of fire retardants and clay used were varied to study the effect of each on thermal stability and mechanical properties of the polymer. The samples were prepared by bulk polymerization and analyzed by X-ray diffraction, thermogravimetric analysis, cone calorimetry, Fourier Transform infrared spectroscopy and the evaluation of mechanical properties. The thermal stability of the polymers is enhanced by the presence of the phosphorus-containing fire retardants.

Go to article

Seasonal And Nocturnal Variations Of The Mesospheric Sodium Layer At Starfire Optical Range, New Mexico, Hu Xiong, Chester S. Gardner, Alan Z. Liu Jan 2003

Seasonal And Nocturnal Variations Of The Mesospheric Sodium Layer At Starfire Optical Range, New Mexico, Hu Xiong, Chester S. Gardner, Alan Z. Liu

Physical Sciences - Daytona Beach

The seasonal variations of the mesospheric sodium layer structure over Starfire Optical Range (SOR: 35ºN, 106.5ºW), New Mexico are characterized using 46 night data of Na wind/temperature lidar observations collected from Jan. 1998 to May 2000. The column abundance has a mean value of 5.06 x 109 cm -2 and strong annual oscillations of with a maximum in November and a minimum in June and July. The annual mean rms width of the sodium layer is 4.30 km and the mean centroid height is 91.60 km. Semiannual oscillations are evident in seasonal variations of the rms width and the …

Go to article

Affine Manifolds, Log Structures, And Mirror Symmetry, Mark Gross, Bernd Siebert Jan 2003

Affine Manifolds, Log Structures, And Mirror Symmetry, Mark Gross, Bernd Siebert

Turkish Journal of Mathematics

We outline work in progress suggesting an algebro-geometric version of the Strominger-Yau-Zaslow conjecture. We define the notion of a toric degeneration, a special case of a maximally unipotent degeneration of Calabi-Yau manifolds. We then show how in this case the dual intersection complex has a natural structure of an affine manifold with singularities. If the degeneration is polarized, we also obtain an intersection complex, also an affine manifold with singularities, related by a discrete Legendre transform to the dual intersection complex. Finally, we introduce log structures as a way of reversing this construction: given an affine manifold with singularities with …

Go to article

Duality And Fibrations On G_2 Manifolds, Sergei Gukov, Shing-Tung Yau, Eric Zaslow Jan 2003

Duality And Fibrations On G_2 Manifolds, Sergei Gukov, Shing-Tung Yau, Eric Zaslow

Turkish Journal of Mathematics

We argue that G_2 manifolds for M-theory admitting string theory Calabi-Yau duals are fibered by coassociative submanifolds. Dual theories are constructed using the moduli space of M-five-brane fibers as target space. Mirror symmetry and various string and M-theory dualities involving G_2 manifolds may be incorporated into this framework. To give some examples, we construct two non-compact manifolds with G_2 structures: one with a K3 fibration, and one with a torus fibration and a metric of G_2 holonomy. Kaluza-Klein reduction of the latter solution gives abelian BPS monopoles in 3 + 1 dimensions.

Go to article

U(1)-Invariant Special Lagrangian 3-Folds In {\Mathbb C}^3 And Special Lagrangian Fibrations, Dominic Joyce Jan 2003

U(1)-Invariant Special Lagrangian 3-Folds In {\Mathbb C}^3 And Special Lagrangian Fibrations, Dominic Joyce

Turkish Journal of Mathematics

This is a survey of the author's series of three papers [8, 9, 10] on special Lagrangian 3-folds (SL 3-folds) in {\mathbb C}^3 invariant under the U(1)-action (z_1,z_2,z_3)e^{i\theta}z_1, e^{-i\theta}z_2,z_3), and their sequel {\mathbb C} [11] on special Lagrangian fibrations and the SYZ Conjecture. We briefly present the main results of these four long papers, giving some explanation and motivation, but no proofs. The aim is to make the results and ideas accessible to String Theorists and others who have an interest in special Lagrangian 3-folds and fibrations, but have no desire to read pages of technical analysis. Let N be …

Go to article

Polyhedral Approximations Of Riemannian Manifolds, Anton Petrunin Jan 2003

Polyhedral Approximations Of Riemannian Manifolds, Anton Petrunin

Turkish Journal of Mathematics

I'm trying to understand which Riemannian manifolds can be Lipschitz approximated by polyhedral spaces of the same dimension with curvature bounded below. The necessary conditions I found consist of some special inequality for curvature at each point (the geometric curvature bound). This inequality is also sufficient condition for local approximation. I conjecture that it is also a sufficient condition for global approximation, and I can prove it if the curvature bound is positive. In general I can prove it only with the additional assumption that tangent bundle of the manifold is stably trivial.

Go to article

Fuzzy Ideals In Gamma-Rings, Mehmet Ali̇ Öztürk, Mustafa Uçkun, Young Bae Jun Jan 2003

Fuzzy Ideals In Gamma-Rings, Mehmet Ali̇ Öztürk, Mustafa Uçkun, Young Bae Jun

Turkish Journal of Mathematics

The converse of [7, Theorem 3.3] is provided. For an Artinian \Gamma-ring, a few results are investigated.

Go to article

High Frequency Atmospheric Gravity Wave Damping In The Mesosphere, G. R. Swenson, Alan Z. Liu, F. Li, J. Tang Jan 2003

High Frequency Atmospheric Gravity Wave Damping In The Mesosphere, G. R. Swenson, Alan Z. Liu, F. Li, J. Tang

Physical Sciences - Daytona Beach

Correlative measurements of temperature and winds by Na lidar and brightness in OH and O2 Atmospheric band airglow have been made at Albuquerque, NM and Maui, HI for a study of high frequency (period less than 30 minutes) Atmospheric Gravity Waves. Wave studies from four nights have been made and the correlative information describes the intrinsic wave properties with altitude, their damping characteristics, and resulting accelerations to the large scale circulation in the 85-100 km altitude region. Generally, saturated to super-saturated conditions were observed below 95 km. Above this altitude, they were less saturated to freely propagating.

Go to article

Measurements Of Atmospheric Stability In The Mesopause Region At Starfire Optical Range, Nm, Yucheng Zhao, Alan Z. Liu, Chester S. Gardner Jan 2003

Measurements Of Atmospheric Stability In The Mesopause Region At Starfire Optical Range, Nm, Yucheng Zhao, Alan Z. Liu, Chester S. Gardner

Physical Sciences - Daytona Beach

The structure and seasonal variations of static (convective) and dynamic (shear) instabilities in the mesopause region (80–105 km) are examined using high-resolution wind and temperature data obtained with a Na lidar at the Starfire Optical Range, NM. The probabilities of static and dynamic instability are sensitive functions of N2/S2, where N is the buoyancy frequency and S is the total vertical shear in the horizontal winds. The mesopause region is most stable in summer when the mesopause is low, N is large and S is small. Monthly mean N2/S2 varies from …

Go to article

Regularity Of Minimizers Of The Calculus Of Variations In Carnot Groups Via Hypoellipticity Of Systems Of Hörmander Type, Luca Capogna, Nicola Garofalo Jan 2003

Regularity Of Minimizers Of The Calculus Of Variations In Carnot Groups Via Hypoellipticity Of Systems Of Hörmander Type, Luca Capogna, Nicola Garofalo

Mathematics Sciences: Faculty Publications

We prove the hypoellipticity for systems of Hörmander type with constant coefficients in Carnot groups of step 2. This result is used to implement blow-up methods and prove partial regularity for local minimizers of non-convex functionals, and for solutions of non-linear systems which appear in the study of non-isotropic metric structures with scalings. We also establish estimates of the Hausdorff dimension of the singular set.

Go to article

Long Time Behavior Of Solutions To The 3d Compressible Euler Equations With Damping, Thomas C. Sideris, Becca Thomases, Dehua Wang Jan 2003

Long Time Behavior Of Solutions To The 3d Compressible Euler Equations With Damping, Thomas C. Sideris, Becca Thomases, Dehua Wang

Mathematics Sciences: Faculty Publications

The effect of damping on the large-time behavior of solutions to the Cauchy problem for the three-dimensional compressible Euler equations is studied. It is proved that damping prevents the development of singularities in small amplitude classical solutions, using an equivalent reformulation of the Cauchy problem to obtain effective energy estimates. The full solution relaxes in the maximum norm to the constant background state at a rate of t-3/2. While the fluid vorticity decays to zero exponentially fast in time, the full solution does not decay exponentially. Formation of singularities is also exhibited for large data.

Go to article

Planar Minimally Rigid Graphs And Pseudo-Triangulations, Ruth Haas, David Orden, Günter Rote, Francisco Santos, Herman Servatius, Diane Souvaine, Ileana Streinu, Walter Whiteley Jan 2003

Planar Minimally Rigid Graphs And Pseudo-Triangulations, Ruth Haas, David Orden, Günter Rote, Francisco Santos, Herman Servatius, Diane Souvaine, Ileana Streinu, Walter Whiteley

Mathematics Sciences: Faculty Publications

Pointed pseudo-triangulations are planar minimally rigid graphs embedded in the plane with pointed vertices (adjacent to an angle larger than π). In this paper we prove that the opposite statement is also true, namely that planar minimally rigid graphs always admit pointed embeddings, even under certain natural topological and combinatorial constraints. The proofs yield efficient embedding algorithms. They also provide - to the best of our knowledge - the first algorithmically effective result on graph embeddings with oriented matroid constraints other than convexity of faces. These constraints are described by combinatorial pseudo-triangulations, first defined and studied in this paper. Also …

Go to article

Unification Scale, Proton Decay, And Manifolds Of G2 Holonomy, Tamar Friedmann, Edward Witten Jan 2003

Unification Scale, Proton Decay, And Manifolds Of G2 Holonomy, Tamar Friedmann, Edward Witten

Mathematics Sciences: Faculty Publications

Models of particle physics based on manifolds of G2 holonomy are in most respects much more complicated than other string-derived models, but as we show here they do have one simplification: threshold corrections to grand unification are particularly simple. We compute these corrections, getting completely explicit results in some simple cases. We estimate the relation between Newton’s constant, the GUT scale, and the value of αGUT , and explore the implications for proton decay. In the case of proton decay, there is an interesting mechanism which (relative to four-dimensional SUSY GUT’s) enhances the gauge boson contribution to p → π …

Go to article

A Dynamical System For Plant Pattern Formation: A Rigorous Analysis, Pau Atela, Christophe Golé, S. Hotton Jan 2003

A Dynamical System For Plant Pattern Formation: A Rigorous Analysis, Pau Atela, Christophe Golé, S. Hotton

Mathematics Sciences: Faculty Publications

We present a rigorous mathematical analysis of a discrete dynamical system modeling plant pattern formation. In this model, based on the work of physicists Douady and Couder, fixed points are the spiral or helical lattices often occurring in plants. The frequent occurrence of the Fibonacci sequence in the number of visible spirals is explained by the stability of the fixed points in this system, as well as by the structure of their bifurcation diagram. We provide a detailed study of this diagram.

Go to article

Genomic Instability Induced By Two Chemical Carcinogens, Cadmium And Nickel And By Particulate Titanium Debris From An Implant, Natasha Coen Jan 2003

Genomic Instability Induced By Two Chemical Carcinogens, Cadmium And Nickel And By Particulate Titanium Debris From An Implant, Natasha Coen

Doctoral

It has been established that cells surviving radiation may produce descendants many cell divisions post-exposure in which, there are high incidences of chromosomal aberrations arising de novo, gene mutation and lethal mutations/delayed cell death. These effects are collectively known as genomic instability and are induced at frequencies greater than that of spontaneous mutations. Formally this syndrome ‘genomic instability’ has only been definitively proven to occur following irradiation. This leads us to the consideration that heavy metals could also induce the genomic instability phenotype, and if so, it could have implications for those exposed through their occupation, through smoking or for …

Go to article

The Extreme Software Development Series: An Open Curricular Framework For Applied Capstone Courses, Konstantin Läufer, George K. Thiruvathukal Jan 2003

The Extreme Software Development Series: An Open Curricular Framework For Applied Capstone Courses, Konstantin Läufer, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

We describe an open, flexible curricular framework for offering a collection of advanced undergraduate and graduate courses in software development. The courses offered within this framework are further unified by combining solid foundations with current technology and play the role of capstone courses in a modern software development track. Our initiative has been very successful with all stakeholders involved.

Go to article

Automatic Statistical Processing Of Multibeam Echosounder Data, Brian R. Calder Jan 2003

Automatic Statistical Processing Of Multibeam Echosounder Data, Brian R. Calder

Center for Coastal and Ocean Mapping

This paper presents the CUBE (Combined Uncertainty and Bathymetry Estimator) algorithm. Our aim is to take advantage of statistical redundancy in dense Multibeam Echosounder data to identify outliers while tracking the uncertainty associated with the estimates that we make of the true depth in the survey area. We recognise that a completely automatic system is improbable, but propose that significant benefits can still be had if we can automatically process good quality data, and highlight areas that probably need further attention. We outline CUBE and its associated support structures, and apply it to a dataset from Woods Hole, MA, USA. …

Go to article

Advances In The Use Of Neurophysiologycally-Based Fusion For Visualization And Pattern Recognition Of Medical Imagery, Mario Aguilar, Joshua New, Erion Hasanbelliu Jan 2003

Advances In The Use Of Neurophysiologycally-Based Fusion For Visualization And Pattern Recognition Of Medical Imagery, Mario Aguilar, Joshua New, Erion Hasanbelliu

Research, Publications & Creative Work

The ever increasing number of image modalities available to doctors for diagnosis purposes has established an important need to develop techniques that support work-load reduction and information maximization. To this end, we have improved on an image fusion architecture first developed for night vision applications. This technique, presented at Fusion 2002, utilizes 3D operators to combine volumetric image sets while maximizing information content. In our approach, we have combined the use of image fusion and userdefined pattern recognition within a 3D human-computer interface. Here, we present our latest advances towards enhancing information visualization and supporting pattern recognition. We also report …

Go to article

Mapping And Characterizing Subtidal Oyster Reefs Using Acoustic Techniques, Underwater Videography And Quadrat Counts, Raymond E. Grizzle, J R. Adams, Semme J. Dijkstra, Brian Smith, R W. Ward Jan 2003

Mapping And Characterizing Subtidal Oyster Reefs Using Acoustic Techniques, Underwater Videography And Quadrat Counts, Raymond E. Grizzle, J R. Adams, Semme J. Dijkstra, Brian Smith, R W. Ward

Center for Coastal and Ocean Mapping

Populations of the eastern oyster Crassostrea virginica have been in long-term decline in most areas. A major hindrance to effective oyster management has been lack of a methodology for accurately and economically obtaining data on their distribution and abundance patterns. Here, we describe early results from studies aimed at development of a mapping and monitoring protocol involving acoustic techniques, underwater videography, and destructive sampling (excavated quadrats). Two subtidal reefs in Great Bay, New Hampshire, were mapped with side-scan sonar and with videography by systematically imaging multiple sampling cells in a grid covering the same areas. A single deployment was made …

Go to article

First Prev Next Last