| Acoustic Detection from Aerial Balloon Platform |
DEC 2004 |
9 pages |
| Authors:
C. Reiff; T. Pham; M. Scanlon; J. Noble; A. Van Landuyt; J. Petek; J. Ratches; ARMY RESEARCH LAB ADELPHI MD
|
 | The US Army Research Laboratory (ARL) and US Army Night Vision and Electronic Sensors Directorate (NVESD) are leading the research and development in autonomous sensing and sensor networks for the Networked Sensors for the Future Force (NSfFF) and Future Combat System (FCS). With the emphasis being shifted to lighter and more mobile forces, ARL and NVESD have been collaborating and exploring various mobile platforms such as robotic vehicles and aerial ... |
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| Networked Acoustic Sensor Array's Performance During 2004 Horizontal Fusion - Warrior's Edge Demonstration |
DEC 2004 |
9 pages |
| Authors:
Michael V. Scanlon; Stuart H. Young; David B. Hillis; ARMY RESEARCH LAB ADELPHI MD
|
| As the Army transforms to the Future Force, particular attention must be paid to operations in Complex and Urban Terrain. because our adversaries realize that we don't have battlefield dominance in the urban environment, and because population growth and migration to urban environments is still on the increase, our adversaries will continue to draw us into operations in the urban environment. The Army Research Laboratory (ARL) is developing technology to ... |
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| Incorporation of Atmospheric Flow Fields and Ground Interactions into Acoustic Finite-Difference, Time-Domain Simulations |
DEC 2004 |
9 pages |
| Authors:
D. K. Wilson; David H. Marlin; Sandra L. Collier; Neill P. Symons; David F. Aldrige; Vladimir E. Ostashev; COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
|
| By providing highly realistic simulations of sound propagation through complex atmospheric and terrain environments, finite-difference time- domain (FDTD) techniques can potentially reduce development time and improve the battlefield performance of acoustic sensors. In this paper, we summarize recent progress in improving two key aspects of acoustic FDTD calculations for the atmosphere: (1) development of a rigorous implementation of sound propagation in a moving, inhomogeneous fluid, and (2) formulation and numerical ... |
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| Volume Sensor Development Test Series 2- Lighting Conditions, Camera Settings, and Spectral and Acoustic Signatures (CD-ROM) |
24 NOV 2004 |
|
| Authors:
James A. Lynch; Susan L. Rose-Pehrsson; Daniel A. Steinhurst; Stephen C. Wales; Frederick W. Williams; NAVAL RESEARCH LAB WASHINGTON DC
|
 | ELECTRONIC FILE CHARACTERISTICS: 776 files; Adobe Acrobat (.PDF), Bitmap (.BMP), .JPEG image, and DataLogger files. PHYSICAL DESCRIPTION: 1 CD-ROM; 4 3/4 in.; 283 MB and 1 hardcopy final report. SYSTEMS DETAIL NOTE: ABSTRACT: Real-scale fire tests in mock ship compartments were conducted to collect data of acoustic and spectral sensors and to experimentally evaluate the fire detection performance of three commercially available video image fire detection systems under various ... |
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| Wearable Sparse-Conformal-Acoustic-Networks for Tracking and ID of Urban Targets (CD-ROM) |
17 NOV 2004 |
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| Authors:
Bernard Widrow; Victor Eliashberg; CARDINAL RESEARCH LLC STANFORD CA
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| ELECTRONIC FILE CHARACTERISTICS: 72 files; Adobe Acrobat (.PDF), MS Word (.DOC), and Winamp media file (.WAV). PHYSICAL DESCRIPTION: 1 CD-ROM; 4 3/4 in.; 14 MB. SYSTEMS DETAIL NOTE: ABSTRACT: The objective of the research is the development of wearable acoustic array technology to enable a wirelessly connected squad of soldiers in an urban battle field to detect, localize, track, and categorize acoustic target signals. For the individual soldiers, sensitive ... |
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| The MIT Lincoln Laboratory RT-04F Diarization Systems: Applications to Broadcast Audio and Telephone Conversations |
Nov 2004 |
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| Authors:
D A Reynolds; P Torres-Carrasquillo; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
|
| Audio diarization is the process of annotating an input audio channel with information that attributes (possibly overlapping) temporal regions of signal energy to their specific sources. These sources can include particular speakers, music, background noise sources, and other signal source/channel characteristics. Diarization has utility in making automatic transcripts more readable and in searching and indexing audio archives. In this paper we describe the systems developed by MITLL and used in ... |
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| Marine Animal Sound Database. Twelve Years of Tracking 52-Hz Whale Calls from a Unique Source in the North Pacific |
12 OCT 2004 |
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| Authors:
William A. Watkins; Mary Ann Daher; Joseph E. George; David Rodriguez; WOODS HOLE OCEANOGRAPHIC INST MA BIOLOGY DEPT
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| Long-term monitoring of underwater sounds using U.S. Navy SOSUS and other hydrophone arrays allowed us to follow the seasonal distribution of underwater calls produced by blue, fin and humpback whales across the North Pacific. These new data from this current study have been added to data of previous 7 years' deep-water monitoring,enabling us to document year-to-year variations in marine mammal calling. These data have also been added to the marine ... |
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| Vehicle Tracking using Acoustic and Video Sensors |
04 OCT 2004 |
9 pages |
| Authors:
Aswin C. Sankaranayanan; Qinfen Zheng; Rama Chellappa; Volkan Cevher; James H. McClellan; Gang Qian; MARYLAND UNIV COLLEGE PARK
|
| In target tracking, fusing multi-modal sensor data under a power- performance trade-o is becoming increasingly important. Proper fusion of multiple modalities can help in achieving better tracking performance while decreasing the total power consumption. In this paper, we present a framework for tracking a target given joint acoustic and video observations from a co- located acoustic array and a video camera. We demonstrate on eld data that tracking of the ... |
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| Effect of Sonic Thermographic Inspection on Fatigue Crack Growth in an Al Alloy |
OCT 2004 |
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| Authors:
Kelly A. Tsoi; Nik Rajic; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION VICTORIA (AUSTRALIA) AIR VEHICLES DIV
|
| Sonic thermography has recently emerged as an important inspection technique capable of resolving inspection problems that contemporary methods have struggled with, such as tightly closed cracks in metallic structures and kissing bonds in composite repairs. The technique uses elastic waves injected by an acoustic horn resonating at typically either 20 or 40 kHz, which often excites lateral motion at the surfaces of a defect. This motion induces frictional heating and ... |
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| Location, Characterization and Quantification of Hydroacoustic Signals in the Indian Ocean |
OCT 2004 |
60 pages |
| Authors:
M. Tolstoy; D. R. Bohnenstiehl; LAMONT-DOHERTY EARTH OBSERVATORY PALISADES NY
|
| In this final report we summarize research accomplished on the project titled, Location, Characterization and Quantification of Hydroacoustic Signals in the Indian Ocean. Our initial goals were to locate, characterize and quantify hydroacoustic signals recorded on the three available hydroacoustic stations in the Indian Ocean, and this was accomplished for available data through May 2003. However, shortly thereafter our contract was rescoped to focus on high frequency propagation through the ... |
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| Characterization of Breast Masses Using a New Method of Ultrasound Contract Agent Imaging in a 3D Mapping of Vascular Anomalies |
OCT 2004 |
20 pages |
| Authors:
Gerald L. LeCarpentier; MICHIGAN UNIV ANN ARBOR
|
| Doppler ultrasound and other imaging modalities have been used to assess characteristics of vasculature associated with malignant breast masses. 3D contrast refill imaging should help visualize slow-flow in small neo-vasculature associated with these masses. The dual-transducer method proposed should provide vascular mapping while minimizing acquisition time, the major limitation of techniques such as interval-imaging (I-I) and real-time (RT) imaging. Phantom tube-flow studies from Y2 were further quantified. A phantom kidney ... |
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| Inverted Echo Sounder Data Report. Ulleung Basin of Japan/East Sea. June 1999 to July 2001 |
Oct-2004 |
107 pages |
| Authors:
Mark Wimbush; Youngsheng Xu; William Teague; Karen L Tracey; D R Watts; Douglas A Mitchell; RHODE ISLAND UNIV NARRAGANSETT GRADUATE SCHOOL OF OCEANOGRAPHY
|
| Observations were conducted from June 1999 to July 2001 to study the shallow and deep current variability in the southwest Japan/East Sea. Data were collected during the field experiment with a two-dimensional array of pressure-gauge equipped inverted echo sounders (PIES) and deep recording current meters (RCM). The collection, processing and calibration of the PIES are documented in this report. Descriptions of the processes used to identify and remove jumps (offsets) ... |
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| Using Adaptive Simulated Annealing to Estimate Ocean Bottom Acoustic Properties from Acoustic Data |
30 SEP 2004 |
137 pages |
| Authors:
Peter D. Neumann; Gregory Muncill; PLANNING SYSTEMS INC RESTON VA
|
| Report developed under SBIR contract for topic N99-217. The effective use of active sonar systems in littoral environments relies on the accurate knowledge of the acoustic environment. This Phase II SBIR provides a solution to the problem of estimating the local, in-situ geoacoustic properties of the ocean bottom from measured acoustic data. The approach used in the Phase I and Phase II SBIR has been to use Navy standard models ... |
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| Broadband and Wide Field of View Composite Transducer Array |
23 SEP 2004 |
12 pages |
| Authors:
Kim C. Benjamin; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A composite transducer array comprises a piezoelectric polymer composite panel, a continuous electrode coupled to a first surface of the composite panel, and a plurality of electrically-isolated electrode segments coupled to a second surface of the composite panel. Each electrode segment is shaped as an angular segment of a circular ring. The electrode segments are arranged to define an array of concentric circular rings of electrode segments. |
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| Summary Report on A Seamap-C Chirp Deconvolution Algorithm With Demonstrations Using Synthetic and Field Data |
13 SEP 2004 |
47 pages |
| Authors:
Dennis A. Lindwall; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOSCIENCES DIV
|
| This report describes several ways to generate a chirp signal for the Seamap-C side-scan sonar system and then to remove the chirp signal from the field data to produce high-resolution sea floor images. Synthetic data are generated using one of several chirps according to the system specifications, data collection methods, and preliminary processing of the Seamap-C system. These synthetic data files, as well as field data, are read by the ... |
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| Non-Rayleigh Reverberation Studies |
07 SEP 2004 |
104 pages |
| Authors:
Douglas A. Abraham; PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
|
| The primary focus of the research was on developing a statistical model for non-Rayleigh reverberation that allowed for analysis of the reverberation statistics, and therefore the sonar system probability of false alarm, as a function of sonar system and environmental parameters. Non-Rayleigh reverberation is a statistical representation of clutter in active sonar systems. False alarms arising from clutter are recognized as the primary hindrance to automating the detection-classification-localization (DCL) sonar ... |
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| Tactical Web Services: Using XML and Java Web Services to Conduct Real- Time Net-Centric Sonar Visualization |
SEP 2004 |
249 pages |
| Authors:
Scott Rosetti; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| With the unveiling of ForceNet, the Navy's architectural framework for how naval warfare is to be conducted in the information age, much of the technological focus has been placed on Web technology. One of the most promising technologies is Web services. Web services provide for a standard way to move and share data more reliably, securely, and quickly. The capabilities imbedded in Extensible Markup Language (XML) and Simple Object Access ... |
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| Utilizing Network-Enabled Command and Control Concepts to Enhance ASW Effectiveness |
SEP 2004 |
63 pages |
| Authors:
Ralph Klingbeil; John Shannon; George Galdorisi; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| This report describes an analysis of two selected concepts for improving Anti-Submarine Warfare (ASW) performance and effectiveness by means of network-enabled sharing of information during ASW operations. These concepts are identified as Shared Situational Awareness (SSA) and Collaborative Information Environment (CIE). It is shown that the application of queueing theory models provide useful tools for quantitatively estimating the value-added of implementing these concepts. In addition, queueing theory can be used ... |
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| Vertical Directionality of Low-Frequency Wind Noise and Vertical Array Optimization for the Wind Noise Limit |
27 AUG 2004 |
21 pages |
| Authors:
Thomas J. Hayward; Richard M. Heitmeyer; NAVAL RESEARCH LAB WASHINGTON DC
|
| Normal mode-based noise modeling is applied to investigate the structure and the environment dependence of vertical wind noise directionality and the optimal design of vertical arrays for detection in a wind noise background, using, as examples, two deep-water sites, one in the North Atlantic and the other in the North Pacific. The contributions to the noise directionality of the overhead (direct-path), surface-interacting, and sediment- interacting components of the noise field ... |
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| Sedimentology of a Morphologically Complex Seafloor Environment, New Jersey Continental Shelf |
25 AUG 2004 |
5 pages |
| Authors:
Christopher K. Sommerfield; DELAWARE UNIV LEWES COLL OF MARINE STUDIES
|
| The overarching goal of this research was to advance our understanding of "geologic clutter", acoustic anomalies created by natural sub- seafloor features such as infilled paleochannels, using the continental shelf off New Jersey as a natural laboratory. As part of the ONR Geoclutter initiative, the objectives of this project were as follows: (1) to identify modern Holocene sedimentary processes responsible for the morphology and sedimentological heterogeneity of the seafloor; and ... |
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| Close Range Sonar System and Method |
11 AUG 2004 |
20 pages |
| Authors:
G. C. Carter; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A system for close range sonar is provided. The system provides sufficient warning to permit maneuvering to avoid a close encounter even in the forward starboard/port regions, which have been problematic in the past due to ownship noise. The system utilizes a hull mounted sonar array and a towed sonar array which may be controlled in position to provide sufficient separation of noise received by both sonar arrays such that ... |
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| Long-Range High Coverage Rate Synthetic Aperture Sonar for ASW and MCM Phase I: SAS Validation Experiments |
AUG 2004 |
219 pages |
| Authors:
Angela Putney; Matt Nelson; James Campbell; Eric S. Chang; DYNAMICS TECHNOLOGY INC TORRANCE CA
|
| In October 2003, Dynamics Technology, Inc. (DTI) and L-3 Communications Ocean Systems (L-3OS) took the L-3OS Seahawk 1.4 kHz variable depth sonar with twin-line receive array to sea and collected active sonar data against the Ex-USS Salmon (SS-573, diesel submarine) and M/S Bidevind (freighter sunk by torpedo) off the NJ/NY coast. DTI processed the data as synthetic aperture sonar (SAS) imagery. The limits of effective SAS processing were set by ... |
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| Application of Non-Contact Hybrid Acoustical Techniques for Remote Inspection of Naval Structures |
AUG 2004 |
28 pages |
| Authors:
B. B. Djordjevic; Robert E. Green Jr; JOHNS HOPKINS UNIV BALTIMORE MD G W C WHITING SCHOOL OF ENGINEERING
|
| The Johns Hopkins University Center for Nondestructive Evaluation (CNDE) has pioneered the development of non-contact remote ultrasonic technology. In this project, we have developed, optimized, and applied non- contact ultrasonic methods of non-intrusive, remote inspection of advanced materials and assessed the feasibility of this technology for implementation on Naval structures. Ultrasonic testing of material properties is a demonstrated technology and has proven to be a robust industrial tool. The major ... |
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| Modeling of Sonar Transducers and Arrays (CD-ROM) |
14 JUL 2004 |
|
| Authors:
G. W. Benthien; S. L. Hobbs; SPACE AND NAVAL WARFARE SYSTEMS CENTER SAN DIEGO CA
|
| ELECTRONIC FILE CHARACTERISTICS: 31 files; Adobe Acrobat (.PDF) and MS Word (.DOC). PHYSICAL DESCRIPTION: 1 computer laser optical disc (CD-ROM); 4 3/4 in.; 104 MB. SYSTEMS DETAIL NOTE: ABSTRACT: This report contains a number of topics that the authors have found to be important in the modeling of sonar transducers and transducer arrays. Much of the material in this report is taken from the Handbook of Acoustic Projector Technology ... |
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| Science, Technical Innovation and Applications in Bioacoustics: Summary of a Workshop |
01 JUL 2004 |
575 pages |
| Authors:
John G. Rees; BRITISH GEOLOGICAL SURVEY (BGS) NOTTINGHAM (UNITED KINGDOM)
|
| The Science, Technical Innovation and Applications in Bioacoustics Workshop was held at the Marine Hotel, North Berwick, East Lothian, Scotland between 4-5 May 2004. focused upon three main topics: 1) The state of our understanding of the basic science of bioacoustics - summarizing what we know, and what we don't know, about acoustic signals produced by animals and how they acquire knowledge about their environment. 2) The conceptual basis for ... |
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| The Use of Hydroacoustic Phases for the Detection of Oceanic Events: Observations and Numerical Modeling |
JUL 2004 |
63 pages |
| Authors:
Catherine DE Groot-Hedlin; Donna Blackman; John Orcutt; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA
|
| Hydroacoustic monitoring of the Comprehensive Nuclear Test Ban Treaty (CTBT) requires the ability to detect and locate phenomena that give rise to acoustic signals. An improved understanding of the coupling of seismic energy to acoustic energy is necessary to improve location estimates of earthquakes and volcanic eruptions. Using known variations in near-source bathymetry, the authors demonstrated that scattering of seismic to acoustic energy at a rough seafloor yields the approximate ... |
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| Development of Acoustic Based, Multi-tasking Sensing and Actuation Capabilities for Gas Turbines |
30 JUN 2004 |
19 pages |
| Authors:
Tim Lieuwen; GEORGIA INST OF TECH ATLANTA SCHOOL OFAEROSPACE ENGINEERING
|
| This program is developing acoustic techniques for non-intrusive sensing and actuation of gas flows. Controlling and/or monitoring the degree of mixing between constituents of a multi-component media is a key problem in a variety of applications. Monitoring such mixing processes necessarily requires capabilities for quantification of the level of "mixedness." However, quantification of molecular mixedness levels, as opposed to macro-scale entrainment, is difficult. Under this program, we have demonstrated the ... |
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| Reduced Rank Wiener Filters in Optimized Coordinates for Partially Adaptive Filtering in Passive and Active Sonar Arrays |
25 JUN 2004 |
15 pages |
| Authors:
Louis Scharf; COLORADO STATE UNIV FORT COLLINS DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| We summarize the results of our most recent ONR Contract, "Reduced Rank Wiener Filters in Optimized Coordinates for Partially Adaptive Filtering in Passive and Active Sonar Arrays," ONR Contract N00014-01-1-1019, by giving a narrative account of what we have found for reduced-rank detection and estimation, conjugate direction Wiener filters, beamforming and diversity combining, and matched and adaptive subspace detection. We offer a discussion of open questions, as these inform our ... |
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| Method for Classifying a Random Process for Data Sets in Arbitrary Dimensions |
09-Jun-2004 |
26 pages |
| Authors:
Jr J; Francis O'Brien; Chung T Nguyen; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A method is provided for automatically characterizing data sets containing data points described by d-dimensional vectors obtained by measurements, such as with sonar arrays, as either random or non-random. The data points are located by the d-dimensional vectors in a d-dimensional Euclidean space which may comprise any number d of dimensions and may comprise more than three dimensions. Large or small sets of data may be analyzed. A virtual volume ... |
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| US-Japan Cooperative Research on Biology-Inspired Precision Maneuvering of Underwater Vehicles |
02 JUN 2004 |
4 pages |
| Authors:
Naomi Kato; OSAKA UNIV (JAPAN) DEPT OF NAVAL ARCHITECTURE AND OCEAN ENGINEERING
|
| The objective of this project was to numerically and experimentally evaluate the underwater precision maneuverability of a cylindrical body, in particular the STOP & HOVER motions, by using fore and aft pairs of pectoral fins, similar to their usage in a fish. We examined the hydrodynamic characteristics of a mechanical pectoral fin through experimental and numerical analyses and the optimal match of the fin motions to generate the maximum hydrodynamic ... |
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| Effects of a Suspended Sediment Layer on Acoustic Imagery |
JUN 2004 |
64 pages |
| Authors:
Michael Cornelius; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The Navy's CASS/GRAB sonar model is used to accurately simulate a side-scan sonar image with a mine-like object present through its reverberation characteristics. The acoustic impact of a suspended sediment layer is investigated numerically using CASS/GRAB through changing the volume scattering characteristics of the lower water column. A range of critical values of volume scattering strength were discovered through repeated model simulations. An understanding of the acoustic characteristics of suspended ... |
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| Assessing the Performance of Omni-Directional Receivers for Passive Acoustic Detection of Vocalizing Odontocetes |
JUN 2004 |
57 pages |
| Authors:
John M. Daziens; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Acoustic detection and localization of marine mammals will assist mitigation efforts for various Naval and scientific missions that may impact protected species. This study sought to experimentally quantify the sonar performance of omni-directional receivers as a means to passively detect vocalizing Odontocetes in coastal waters. To accomplish this objective control led experiments using a calibrated mid-frequency sound source were conducted on the San Clemente Island Underwater Range (SCIUR) in July ... |
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| Predicting the Effects of Sea Surface Scatter on Broadband Pulse Propagation With an Ocean Acoustic Parabolic Equation Model |
JUN 2004 |
93 pages |
| Authors:
Richard M. Ead; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Littoral waters when compared to the open ocean create an environment of greater reverberation with acoustic energy scattering from the sea surface, bottom, topographic features, and regions that lack homogeneity within the volume. If the ocean surface is rough on the scale of an acoustic wavelength, considerable scattering can occur that can significantly influence coherent propagation. Because the rough surface is also evolving dynamically such scattering can introduce Doppler shifting ... |
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| Sound Sources and Levels in the Ocean |
24 MAY 2004 |
|
| Authors:
William M. Carey; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
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| The standard definitions found in the American National Standards on Acoustics are applied to common sound sources used in both underwater acoustics research and in naval sonar systems operation. Recommended metrics are quantified for both continuous and transient sources of sound. The standard definitions are reviewed with theoretical sound source models. Requisite metrics are derived and applied to examples of energy sources of sound such as transients from a small ... |
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| Blind Beamforming for Collaborative Array Processing in Sensor Networks |
MAY 2004 |
12 pages |
| Authors:
Kung Yao; CALIFORNIA UNIV LOS ANGELES DEPT OF COMPUTER SCIENCE
|
| The detection, localization, tracking, and identification of a single target by acoustical/seismic measured data are fairly well understood. Many of the methods considered in the SensIT program proven in various ways for a single target in an open-air environment, will not be applicable to multiple targets. In the proposal, we advocated a new algorithm based on an efficient computational Approximate Maximum-Likelihood (AML) method using alternate projection to tackle the multiple ... |
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| Environmental Data Collection Sensor to Decision Aid |
MAY 2004 |
7 pages |
| Authors:
Michael M. Harris; William E. Avera; Leonard D. Bibee; J. M. Null; James Hammack; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOSCIENCES DIV
|
| Historical environmental data is very useful; however, it often suffers from incomplete coverage, low data density and perishability. Accurate near real-time environmental data is critical to the success of Mine Warfare operations as was demonstrated in Operation Iraqi Freedom in clearing the approach to the deep water port of Umm Qasr. Prior to the conflict information on seafloor bottom type, expected mine-case burial rates and water depth was inconsistent and ... |
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| Detection Performance of a Suboptimum Processor in Non-Gaussian Noise |
19 APR 2004 |
66 pages |
| Authors:
Albert H. Nuttall; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| The performance of a suboptimum processor for three different signal types in three different noise backgrounds has been investigated numerically in terms of the receiver operating characteristics and compared with the performance of the optimum processor in the same environments. The three distributions considered are Gaussian, sech, and fourth power; the sech distribution decays exponentially for large arguments, while the fourth-power distribution decays inversely proportional to the fourth power. Noise ... |
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| An Improved Method for Solving Systems of Linear Equations in Frequency Response Problems |
15 APR 2004 |
10 pages |
| Authors:
Martin H. Marcus; NAVAL RESEARCH LAB WASHINGTON DC PHYSICAL ACOUSTICS BRANCH
|
| Vibration and acoustics problems that require solving matrix equations for many frequencies have solutions that vary very little from one frequency to the next. This suggests that an iterative method using the solution at one frequency could be used to obtain the next frequency solution. In this report, the matrix inverse at the first frequency serves as the preconditioner for the preconditioned conjugate gradient method to obtain subsequent frequencies. For ... |
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| Toward Improving the Efficiency and Realism of Coupled Meteorological Acoustic Computer Models for the Forest Canopy |
APR 2004 |
24 pages |
| Authors:
Tunick Arnold; ARMY RESEARCH LAB ADELPHI MD
|
| Several physics-based computer models have been developed to calculate one- and two-dimensional forest canopy micrometeorology and turbulence for future U.S. Army acoustic application research. Individual computer codes have incorporated various computational methods on a uniform grid to solve the meteorological fields. However, it may be possible to improve the efficiency and realism of the coupled meteorological acoustic computer models by introducing variable grid. Variable grid will allow for better distribution ... |
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| Calculations of Inhomogeneous Ground Effects in Outdoor Sound Propagation Using the Boundary Element Method (BEM) |
APR 2004 |
21 pages |
| Authors:
Donald G. Albert; ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
|
| This report summarizes the results of a study to calculate the effect of inhomogeneous ground impedance on acoustic wave propagation. The boundary element method was used to investigate the effect of snow or bare ground patches along the acoustic propagation path. This method can be used to calculate the effect of inhomogeneities in the propagation medium with a relatively small computational effort compared to many other methods (for example, the ... |
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| Acoustic Technology for Landmine Detection |
31 MAR 2004 |
40 pages |
| Authors:
James M. Sabatier; Andi G. Petculescu; MISSISSIPPI UNIV UNIVERSITY NATIONAL CENTER FOR PHYSICAL ACOUSTICS
|
| The Office of Naval Research issued Grant N00014-02-1-0346 for Optical Measurements of Ground Vibrations to the National Center for Physical Acoustics at the University of Mississippi. The University of Mississippi is involved in an applied research program to develop an acoustic technique to detect buried landmines. In this technique, the ground is excited using acoustic or seismic sources which elicit resonance in buried mines. This resonance causes increased amplitude in ... |
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| Acoustic Fuel Shutoff |
24 MAR 2004 |
14 pages |
| Authors:
Anthony A. Ruffa; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| This patent application discloses a system for preventing overflow from a tank being filled. An open-ended elongated tube is disposed in a fuel tank to extend between an opening of the tank at one end and proximate to the bottom of the tank at the other end. A refueling nozzle connected to a source of pressurized fuel or other pressurized liquid has an open end extension to extend through the ... |
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| Indian Rocks Beach Experiment, January-March 2003 |
22 MAR 2004 |
103 pages |
| Authors:
Grant R. Bower; Michael D. Richardson; Kevin B. Briggs; W. C. Vaughan; Conrad S. Kennedy; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| An experiment to characterize subsequent (scour) mine burial was conducted in the winter of 2003 in water depth of 13 meters near Tampa Bay, Florida. Four NRL Acoustic Instrument Mines (AIMs), Six Forschungsanstalt der Bundeswehr fur Wasserschall- und Geophysik (FWG) Instrumented Mines and two each Inert Manta Mines, Rockan Mines and 500 lb bombs were placed on the seafloor and left for a period of approximately 64 days. The instrumented ... |
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| NRL Atmospheric Correction Algorithms for Oceans: Tafkaa User's Guide |
22 MAR 2004 |
39 pages |
| Authors:
Marcos J. Montes; Bo-Cai Gao; Curtiss O. Davis; NAVAL RESEARCH LAB WASHINGTON DC
|
| Tafkaa is an atmospheric correction algorithm for remote sensing of ocean color that has been developed at the Naval Research Laboratory (NRL). This document describes how to use Tafkaa, and presents some background on Tafkaa, including differences and similarities in both the current tabular and 6S versions. Descriptions of various options, restrictions, assumptions, keywords, input files, and output files associated with Tafkaa are also presented. |
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| Detection and Tracking as a Seamless Process |
17 MAR 2004 |
25 pages |
| Authors:
Lawrence Stone; METRON INC MCLEAN VA
|
| Detection and tracking are normally considered separate processes. First the signal processing system associated with a sensor examines the signal to determine whether to call detection. Once detection is called, it is converted to an estimate of one or more of the components of the target's kinematic state, e.g., bearing, position, or velocity. This estimate (contact) is sent to a tracking system that determines whether the contact should be associated ... |
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| Quadratic Forms on Complex Random Matrices and Multi-Antenna Channel Capacity |
16 MAR 2004 |
14 pages |
| Authors:
Tharmalingam Ratnarajah; R. Vaillancourt; OTTAWA UNIV (ONTARIO)
|
| Quadratic forms on complex random matrices and their joint eigenvalue densities are derived for applications in information theory. These densities are represented by complex hypergeometric functions of matrix arguments which can be expressed in terms of complex zonal polynomials. The derived densities are used to evaluate the most important information-theoretic measures the so- called ergodic channel capacity and capacity versus outage of multiple-input multiple-output (MIMO) Rayleigh-distributed wireless communication channels. Both ... |
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| Geolocation of an Audio Source in a Multipath Environment Using Time-of- Arrival |
MAR 2004 |
107 pages |
| Authors:
Jeffrey A. Boggs; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The Air Force and the Department of Defense (DoD) are continually searching for ways to protect U.S. forces, both stateside and abroad. One continuing threat, especially in the current world environment, is gunfire from an unseen sniper. Designated areas, such as a forward deployed base or motorcade route, need to be continuously monitored for sniper fire. Once detected, these gunmen need to be located in real time. One possible method ... |
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| Vibrometric Detection of Beam Damage Due to Inclusions |
MAR 2004 |
130 pages |
| Authors:
Aron J. Reifsnyder; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| The Air Force Institute of Technology, in conjunction with the Structural Health Monitoring branch of the Air Force Research Laboratory, is researching methods of determining effects of notch location and size on beam structures using modal frequency analysis. This thesis explores the ability to detect included notches of varying magnitudes and locations within the frequency domain of an isotropic cantilever beam. A series of experiments employing centerline-notched 2024 T3 and ... |
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| Fury: Robotic In-Situ Inspection/Condition Assessment System for Underground Storage Tanks |
MAR 2004 |
38 pages |
| Authors:
Charles P. Marsh; Amer Siddique; Brian Temple; Vincent M. Hock; Frank Robb; ENGINEER RESEARCH AND DEVELOPMENT CENTER CHAMPAIGN IL CONSTRUCTION ENGINEERING RESEARCH LAB
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| The Code of Federal Regulations (40 CFR 280-281) required all underground storage tanks (USTs) containing petroleum products to be brought into compliance to prevent environmental contamination through leakage. Replacing all older USTs can, in some cases, be prohibitively expensive. One alternative to requiring that tanks pass a precision tightness test is to retrofit USTs with cathodic protection for continued use. This report introduced a remote, robotic UST condition inspection/assessment system ... |
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| Ruggedized Fiber Optic Sound Velocity Profiler |
11 FEB 2004 |
16 pages |
| Authors:
Anthony A. Ruffa; DEPARTMENT OF THE NAVY WASHINGTON DC
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| The present invention relates to an optical fiber cable for use with a system for determining a velocity profile of sound in a medium. The optical fiber cable comprises an inner layer of strength members, an outer layer of strength members, and at least one tube containing at least one optical fiber incorporated into the outer layer. |
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Acoustic Detection and Detectors
