scholarly journals Using matched‐field processing technique to map the forward‐scattered signal

1995 ◽  
Vol 97 (5) ◽  
pp. 3424-3424
Author(s):  
Yung P. Lee
Keyword(s):  
Processing Technique ◽  
Scattered Signal ◽  
Matched Field Processing

REVIEW OF MATCHED FIELD PROCESSING FOR ENVIRONMENTAL INVERSE PROBLEMS

1992 ◽  
Vol 03 (04) ◽  
pp. 691-708 ◽  
Author(s):  
A. TOLSTOY
Keyword(s):  
Underwater Acoustics ◽  
Processing Technique ◽  
High Accuracy ◽  
Inverse Source Problem ◽  
Acoustic Fields ◽  
Signal Processing Technique ◽  
Matched Field Processing ◽  
Recent Success ◽  
Ocean Environment ◽  
Work Done

Matched Field Processing (MFP) is a signal processing technique that has enjoyed much recent success in the Underwater Acoustics community, mainly as a consequence of the high accuracy currently achievable in predictions of non-isotropic, non-planar ocean acoustic fields. MFP is applied to acoustic fields measured on arrays of hydrophones and has been used primarily to solve the inverse source problem, i.e., to determine the unknown range, depth, and bearing of acoustic sources in a known ocean environment. However, the MFP approach has also been applied to the environmental inverse problem, i.e., to determine the characteristics of an unknown ocean environment. This paper will review the work done in this latter area.

EVALUATION OF MASSIVELY PARALLEL COMPUTING FOR EXHAUSTIVE AND CLUSTERED MATCHED-FIELD PROCESSING

1996 ◽  
Vol 04 (02) ◽  
pp. 159-173
Author(s):  
R.G. RACCA ◽  
Z. MENG ◽  
J.M. OZARD ◽  
M.J. WILMUT
Keyword(s):  
Parallel Machine ◽  
Processing Technique ◽  
Parallel Computer ◽  
Massively Parallel ◽  
Computer Algorithms ◽  
Signal Processing Technique ◽  
Matched Field Processing ◽  
Vector Processor ◽  
Execution Speed ◽  
Speedup Factor

Many computer algorithms contain an operation that accounts for a substantial portion of the total execution cost in a frequently executed loop. The use of a parallel computer to execute that operation may represent an alternative to a sheer increase in processor speed. The signal processing technique known as matched-field processing (MFP) involves performing identical and independent operations on a potentially huge set of vectors. To investigate a massively parallel approach to MFP and clustered nearest neighbors MFP, algorithms were implemented on a DECmpp 12000 massively parallel computer (from Digital Equipment and MasPar Corporation) with 8192 processors. The execution time for the MFP technique on the MasPar machine was compared with that of MFP on a serial VAX9000–210 equipped with a vector processor. The results showed that the MasPar achieved a speedup factor of at least 17 relative to the VAX9000. The speedup was 3.5 times higher than the ratio of the peak ratings of 600 MFLOPS for the MasPar versus 125 MFLOPS for the VAX9000 with vector processor. The execution speed on the parallel machine represented 64% of its peak rating. This is much better than what is commonly assumed for a parallel machine and was obtained with modest programming effort. An initial implementation of a massively parallel approach to clustered MFP on the MasPar showed a further order of magnitude increase in speed, for an overall speedup factor of 35.

A New Image Processing Technique for STEM

1974 ◽  
Vol 32 ◽  
pp. 432-433
Author(s):  
Yasushi Kokubo ◽  
Hirotami Koike ◽  
Teruo Someya
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Scanning Electron Microscopy ◽  
Elastic Scattering ◽  
Field Emission ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Energy Analyzer ◽  
Scanning Microscope ◽  
Scanning Electron

One of the advantages of scanning electron microscopy is the capability for processing the image contrast, i.e., the image processing technique. Crewe et al were the first to apply this technique to a field emission scanning microscope and show images of individual atoms. They obtained a contrast which depended exclusively on the atomic numbers of specimen elements (Zcontrast), by displaying the images treated with the intensity ratio of elastically scattered to inelastically scattered electrons. The elastic scattering electrons were extracted by a solid detector and inelastic scattering electrons by an energy analyzer. We noted, however, that there is a possibility of the same contrast being obtained only by using an annular-type solid detector consisting of multiple concentric detector elements.

EM of human atherosclerosis: Aortic fatty streaks with transitional lesion features

1992 ◽  
Vol 50 (1) ◽  
pp. 622-623
Author(s):  
K. Florian Klemp ◽  
J.R. Guyton
Keyword(s):  
Foam Cell ◽  
Cell Formation ◽  
Processing Technique ◽  
Foam Cell Formation ◽  
Tissue Preparation ◽  
Electron Microscopic ◽  
Extracellular Lipid ◽  
Electron Microscopic Cytochemistry ◽  
Human Atherosclerosis ◽  
Clinically Significant

The earliest distinctive lesions in human atherosclerosis are fatty streaks (FS), characterized initially by lipid-laden foam cell formation. Fibrous plaques (FP), the clinically significant lesions, differ from FS in several respects. In addition to foam cells, the FP also exhibit fibromuscular proliferation and a necrotic core region rich in extracellular lipid. The possible transition of FS into mature FP has long been debated, however. A subset of FS described by Katz etal., was intermediate in lipid composition between ordinary FS and FP. We investigated this hypothesis by electron microscopic cytochemistry by employing a tissue processing technique previously described by our laboratory. Osmium-tannic acid-paraphenylenediamine (OTAP) tissue preparation enabled ultrastructural analysis of lipid deposits to discern features characteristic of mature fibrous plaques.

Characterization of microwave-sintered ceramic composites

1993 ◽  
Vol 51 ◽  
pp. 1136-1137
Author(s):  
X. Zhang ◽  
Y. Pan ◽  
T.T. Meek
Keyword(s):  
Matrix Material ◽  
Maximum Output Power ◽  
Ceramic Matrix Composite ◽  
Ceramic Composites ◽  
Processing Technique ◽  
Structure Characterization ◽  
Alumina Powder ◽  
Maximum Output ◽  
Sintered Ceramic

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.

Nanostructure of semiconductor quantum dots in a borosilicate glass matrix by complementary use of HREM and AEM

1990 ◽  
Vol 48 (4) ◽  
pp. 728-729
Author(s):  
M.J. Kim ◽  
L.C. Liu ◽  
S.H. Risbud ◽  
R.W. Carpenter
Keyword(s):  
Quantum Dots ◽  
Borosilicate Glass ◽  
Glass Matrix ◽  
Optical Switching ◽  
Response Times ◽  
Fast Response ◽  
Processing Technique ◽  
Internal Stresses ◽  
Electron Hole ◽  
Spatial Dimensions

When the size of a semiconductor is reduced by an appropriate materials processing technique to a dimension less than about twice the radius of an exciton in the bulk crystal, the band like structure of the semiconductor gives way to discrete molecular orbital electronic states. Clusters of semiconductors in a size regime lower than 2R {where R is the exciton Bohr radius; e.g. 3 nm for CdS and 7.3 nm for CdTe) are called Quantum Dots (QD) because they confine optically excited electron- hole pairs (excitons) in all three spatial dimensions. Structures based on QD are of great interest because of fast response times and non-linearity in optical switching applications.In this paper we report the first HREM analysis of the size and structure of CdTe and CdS QD formed by precipitation from a modified borosilicate glass matrix. The glass melts were quenched by pouring on brass plates, and then annealed to relieve internal stresses. QD precipitate particles were formed during subsequent "striking" heat treatments above the glass crystallization temperature, which was determined by differential thermal analysis.

A Comparative Study of Ant and Genetic Algorithms in Digital Mammography

2018 ◽  
pp. 194-200
Author(s):  
J. Magelin Mary ◽  
Chitra K. ◽  
Y. Arockia Suganthi
Keyword(s):  
Genetic Algorithm ◽  
Image Processing ◽  
Medical Image ◽  
Medical Image Processing ◽  
Processing Technique ◽  
Input Image ◽  
Image Processing Technique ◽  
Computational Time ◽  
Image Mining ◽  
The Individual

Image processing technique in general, involves the application of signal processing on the input image for isolating the individual color plane of an image. It plays an important role in the image analysis and computer version. This paper compares the efficiency of two approaches in the area of finding breast cancer in medical image processing. The fundamental target is to apply an image mining in the area of medical image handling utilizing grouping guideline created by genetic algorithm. The parameter using extracted border, the border pixels are considered as population strings to genetic algorithm and Ant Colony Optimization, to find out the optimum value from the border pixels. We likewise look at cost of ACO and GA also, endeavors to discover which one gives the better solution to identify an affected area in medical image based on computational time.

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