| Fundamental Cases of Urban Acoustics and Their Interaction with Propagating Sound: Phase II |
Sep 2010 |
22 pages |
| Authors:
Alberts; W C II; Mark A Coleman; John M Noble; ARMY RESEARCH LAB ADELPHI MD COMPUTATIONAL AND INFORMATION SCIENCES DIRECTORATE
|
 | An ongoing U.S. Army Research Laboratory (ARL) effort to study fundamental cases of urban acoustics with the goal of enhanced prediction capabilities found that, in Phase I of the study, a single-story isolated building can be adequately described, in some instances, as a wide barrier of finite length. The structure investigated during Phase I was a small, architecturally simple, gabled-roofed building typical of suburban and rural residential housing. To expand ... |
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| Performance Evaluation of a Prototype Underwater Short-Range Acoustic Telemetry Modem |
Sep 2010 |
110 pages |
| Authors:
Pongsakorn Sommai; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis documents the evaluation of the transmitter performance of a short-range underwater acoustic modem. This prototype modem was fabricated by contractor Teledyne Benthos, Inc. and is identified as Model ATM-90X. It was developed for use in the Seastar underwater Local Area Network (LAN). The ATM-90X modem is required to be capable of transferring large amounts of digital data at a range up to 500 m using the 33-55 kHz ... |
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| Time/Frequency Relationships for an FFT-Based Acoustic Modem |
Sep 2010 |
102 pages |
| Authors:
Jenkins; William F II; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis proposes a scheme for short-range (500m) underwater acoustic communications in shallow water. The proposed scheme is a variation on an existing commercial modem reliably used for medium-range (5km) communications in the 9-14 kHz band. The proposed scheme exploits a higher carrier frequency at 45 kHz and increased spectral bandwidth compatible with the short-range link, thus achieving an increased channel capacity. Analytical expressions are provided for the scheme, which ... |
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| Prospective Durability Testing of a Vascular Access Phantom |
Sep 2010 |
7 pages |
| Authors:
Joel M Schofer; Jason T Nomura; Michael J Bauman; Paul R Sierzenski; NAVAL MEDICAL CENTER PORTSMOUTH VA
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| We assessed the acoustic transmission, image quality, and vessel integrity of the Blue PhantomTM 2 Vessel Original Ultrasound Training Model with repeated use. The study consisted of two phases. During the first phase, a portion of the Blue PhantomTM rubber matrix (without a simulated vessel) was placed over a two-tiered echogenic structure and was repeatedly punctured with a hollow bore 18-gauge needle in a 1 cm2 area. During the second ... |
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| A Review of Biological Communication Mechanisms Applicable to Small Autonomous Systems |
Sep 2010 |
108 pages |
| Authors:
Kesshi Jordan; Daniel Calderone; Alexandra Rubin; Alma E Wickenden; ARMY RESEARCH LAB ADELPHI MD
|
| The field of biomimetics has grown in recent years as interest in using biology as an inspiration for technology has grown. Biology constantly optimizes mechanisms, materials, and integrated systems through natural selection. These systems and materials can be incorporated into a variety of applications, using the technology that nature has already developed as a launch point for novel solutions to engineering problems. Nature's mechanisms accomplish a variety of sensory, communications, ... |
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| Auditory and Acoustic Research & Development at Air Force Research Laboratory (AFRL) |
Sep 2010 |
22 pages |
| Authors:
Richard L McKinley; BALL AEROSPACE AND TECHNOLOGIES CORP FAIRBORN OH
|
| The applied research program focuses on developing innovative technologies and procedures and transitioning them to field use. Frequently these products have application not only for Air Force use, but also for use by the Army, Navy, Marine Corps, and civilian sectors. Some examples of recent in-house and contract-developed technologies include the Attenuating Custom Communication Earpiece System (ACCES), high performance active noise reduction earplugs, helmets specifically designed to reduce bone conducted ... |
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| A Literature Survey of Reverberation Modeling: With Emphasis on Bellhop Compatibility for Operational Applications |
Sep 2010 |
38 pages |
| Authors:
Diana F McCammon; MCCAMMON ACOUTICAL CONSULTING WATERVILLE (CANADA)
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| Recent publications of reverberation and scattering strength modeling are reviewed. Emphasis is placed on investigating operationally oriented models (as opposed to research oriented) that may be compatible with the Bellhop propagation model for use within the Environment Modeling Manager (EMM). Special attention is given to the research of Dr. Dale Ellis including his normal mode reverberation model, his clutter model approach, and his scattering strength model. Recommendations are made to ... |
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| Assessment of Hydroacoustic Propagation Using Autonomous Hydrophones in the Scotia Sea |
Sep 2010 |
9 pages |
| Authors:
Haru Matsumoto; Del R Bohnenstiehl; Robert P Dziak; Robert W Embley; Minkyu Park; OREGON STATE UNIV NEWPORT OR COOPERATIVE INST FOR MARINE RESOURCES STUDIES
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| The remote area of the Atlantic Ocean near the Antarctic Peninsula and the South Scotia Sea is a region where acoustic surveillance by International Monitoring System hydrophones is at best limited. Sound originating in this area is either blocked or hindered by the South Georgia, South Sandwich Islands and the associated seafloor ridge system, making the region a potential hydroacoustic blind spot. To investigate the sound propagation and interferences affected ... |
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| IMS Infrasound Monitoring Test Site at Trafelberg, Austria: Preliminary Results from In-Situ Response Measurements of Infrasound Elements |
Sep 2010 |
23 pages |
| Authors:
Thomas Gabrielson; Georgios Haralabus; Stefi Stefanova; PENNSYLVANIA STATE UNIV STATE COLLEGE
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| The International Monitoring System (IMS) of the Comprehensive Nuclear Test-Ban Treaty Organization (CTBTO) has a unique infrasound test site (I99AT) with four wind-noise-reduction pipe-array systems in close enough proximity to allow simultaneous measurements under similar environmental conditions. It was designed as a facility to study the effectiveness of various wind-noise-reduction systems so it is clear of trees, vegetation, or other wind breaks. The persistent winds presented a challenge for response ... |
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| Advancement of Techniques for Modeling the Effects of Atmospheric Gravity-Wave-Induced Inhomogeneities on Infrasound Propagation |
Sep 2010 |
11 pages |
| Authors:
Robert G Gibson; Douglas P Drob; David Broutman; Nathan W Winslow; BBN TECHNOLOGIES CAMBRIDGE MA
|
| Propagation studies of a growing number of infrasound observations indicate that fine-scale atmospheric inhomogeneities contribute to infrasonic arrivals that are not predicted by standard modeling techniques. In particular, gravity waves, or buoyancy waves, are believed to contribute to the multipath nature of infrasound propagation and to cause penetration of infrasound into the classical shadow zones that are predicted by conventional modeling techniques. Propagation modeling studies using basic parameterizations of gravity ... |
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| Infrasound Signal Characteristics from Small Earthquakes |
Sep 2010 |
13 pages |
| Authors:
J M Hale; Stephen J Arrowsmith; Chris Hayward; Relu Burlacu; Kristine L Pankow; Brian W Stump; George E Randall; Steven R Taylor; LOS ALAMOS NATIONAL LAB NM
|
| Understanding the source properties responsible for infrasound generation is critical to developing a seismo-acoustic data discriminant to distinguish between near-surface explosions and earthquakes. The regional seismicity, complex topography, open-pit quarries, and subsurface mining in the Utah region create a unique setting for the study of near-field infrasound. The Utah network has been operating three permanent infrasound arrays collocated with seismic stations NOQ (2006), BGU (2007), and EPU (2007). Additionally, four ... |
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| Sayarim Infrasound Calibration Explosion: Near-Source and Local Observations and Yield Estimation |
Sep 2010 |
14 pages |
| Authors:
Yefim Gitterman; GEOPHYSICAL INST OF ISRAEL HOLON (ISRAEL)
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| A large-scale calibration explosion of about 82 tons of high explosives (HE), assembled as a pyramid on a soft sediment surface, was successfully conducted by the Geophysical Institute of Israel (GII) at Sayarim Military Range (SMR), Negev Desert, Israel, on 26 August 2009. Near-source high-pressure values, measured in the range 200600 m, were higher than predicted, whereas the resulting crater and the seismic magnitude were smaller than expected for this ... |
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| Infrasound as a Depth Discriminant |
Sep 2010 |
12 pages |
| Authors:
Stephen J Arrowsmith; Hans E Hartse; Steven R Taylor; Richard J Stead; Rod W Whitaker; LOS ALAMOS NATIONAL LAB NM
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| The identification of a signature relating depth to a remotely recorded infrasound signal requires a dataset of earthquakes, recorded infrasonically, with well-constrained depths. Although the premise is simple, five significant complications arise: (1) Earthquakes can generate infrasound via a variety of processes, which have occasionally been confused in past studies due to the complexity of the process; (2) mining explosions are efficient infrasound generators and can be mistaken for earthquakes; ... |
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| The Development of Methodologies for Determining Non-Linear Effects in Infrasound Sensors |
Sep 2010 |
12 pages |
| Authors:
Darren M Hart; Harold V Parks; Randy K Rembold; SANDIA NATIONAL LABS ALBUQUERQUE NM
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| The Ground-Based Nuclear Explosion Monitoring Research and Development (GNEM R&D) program at Sandia National Laboratories (SNL) is regarded as a primary center for unbiased expertise in testing and evaluation of geophysical sensors and instrumentation for nuclear explosion monitoring. Over the past year, four new infrasound sensor designs were evaluated for common performance characteristics, i.e., power consumption, response (amplitude and phase), noise, full-scale, and dynamic range. In the process of evaluating ... |
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| Background Acoustic Noise Models for the IMS Hydroacoustic Stations |
Sep 2010 |
12 pages |
| Authors:
Philip E Harben; Terri F Hauk; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Background acoustic noise levels in the ocean have been increasing for the past several decades yet many of our hydroacoustic detection assessment tools use noise models based on data from the 60's and 70's. In some ocean basins, noise levels in the monitoring band (1-100 Hz) have risen 15 dB since the 1960's. To address this issue and provide accurate noise models at each of the six International Monitoring System ... |
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| Enhancing the Contribution of the T-Stations of the IMS Hydroacoustic Network to IDC Processing and Tsunami Warning |
Sep 2010 |
9 pages |
| Authors:
Mark K Prior; Alexander S Opolavskiy; Ronan J Le Bras; Jeff W Given; COMPREHENSIVE NUCLEAR TEST BAN TREATY ORGANIZATION VIENNA (AUSTRIA) PREPARATORY COMMISSION
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| The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) is exploring methods to enhance the operational hydroacoustic processing system for its International Monitoring System (IMS). The hydroacoustic IMS network includes two types of stations, the in-water hydroacoustic stations, consisting of multiple sets of hydrophone triplets, and the land-based T-stations, consisting of multiple seismometers. Hydrophone triplets record signals that efficiently propagate in the SOFAR channel over large distances. Processing at ... |
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| Basic Research on Seismic and Infrasonic Monitoring of the European Arctic |
Sep 2010 |
12 pages |
| Authors:
Frode Ringdal; Tormod Kvaerna; Steven J Gibbons; Svein Mykkeltveit; Johannes Schweitzer; NORSAR KJELLER (NORWAY)
|
| This project is a research effort aimed at improving seismic and infrasonic monitoring tools at regional distances with emphasis on the European Arctic region, which includes the former Novaya Zemlya test site. The project has three main components: a) to improve seismic processing in this region using the regional seismic arrays installed in northern Europe, b) to investigate the potential of using combined seismic/infrasonic processing to characterize events in this ... |
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| The Impact of Masker Fringe and Masker Sparial Uncertainty on Sound Localization |
Sep 2010 |
8 pages |
| Authors:
Brian D Simpson; Robert H Gilkey; Douglas S Brungart; Nandini Iyer; James D Hamil; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH HUMAN EFFECTIVENESS DIRECTORATE
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| Signal-in-noise detection improves when the masker duration extends beyond that of the signal (masker fringe) relative to the case in which the signal and masker are pulsed on/off simultaneously. This improvement has been attributed to the fact that the fringe provides a baseline set of stimulus parameters that serves as a context against which a signal may be detected. Conversely, when the fringe parameters are inconsistent with those of the ... |
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| National Security Issues and the North Pacific Acoustic Laboratory |
30 Aug 2010 |
3 pages |
| Authors:
Peter F Worcester; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA
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| One of the fundamental goals of the ONR-supported North Pacific Acoustic Laboratory (NPAL) project is to further our understanding of the ultimate limits of long-range sonar imposed by ocean variability and the ambient sound field. Although the NPAL project itself is unclassified, the data collected for the NPAL project using bottom-mounted receivers operated by the U.S. Navy are classified. In addition, the results of the NPAL project potentially have implications ... |
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| Transmission Loss and Signal Coherence in Shallow Water Waveguides |
16 Aug 2010 |
7 pages |
| Authors:
William L Siegmann; Wendell J Saintval; RENSSELAER POLYTECHNIC INST TROY NY
|
| This is the Final Technical Report of ONR Award Number N000140310238. During the performance period, Dr. Saintval was supported for research toward his PhD. The overall objectives of the research are in Section II, and a summary of major results is provided in Section III. Presentations are listed in Section IV, and the publication plan for results is indicated in Section V. |
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| A New Acoustic Portal into the Odontocete Ear and Vibrational Analysis of the Tympanoperiotic Complex |
Aug 2010 |
31 pages |
| Authors:
Ted W Cranford; Petr Krysl; Mats Amundin; SAN DIEGO STATE UNIV CA DEPT OF BIOLOGY
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| Global concern over the possible deleterious effects of noise on marine organisms was catalyzed when toothed whales stranded and died in the presence of high intensity sound. The lack of knowledge about mechanisms of hearing in toothed whales prompted our group to study the anatomy and build a finite element model to simulate sound reception in odontocetes. The primary auditory pathway in toothed whales is an evolutionary novelty, compensating for ... |
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| Interaction of Elastic Waves with Corrosion Damage |
Aug 2010 |
7 pages |
| Authors:
Eric D Swenson; Martin P Desimio; Steven E Olson; Hoon Sohn; DAYTON UNIV OH RESEARCH INST
|
| Corrosion inspection and repair accounts for 21% of the total maintenance costs averaged over the Army, Navy, and Marine air and ground vehicles. A reliable automated method for inspection can lead to cost reductions due to avoiding unnecessary tear down and re-assembly. Elastic waves can travel across relatively large distances in plate-like structures and are affected by the presence of corrosion. This paper presents an investigation of the interaction of ... |
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| Acoustic Resonance Classification of Swimbladder-Bearing Fish |
30 Jul 2010 |
|
| Authors:
Timothy K Stanton; Dezhang Chu; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
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 | Long-Term Goals: To understand and exploit the resonance scattering by swimbladder-bearing fish (typically in the 1-10 kHz frequency region). Exploitation of the resonances can significantly reduce ambiguities in interpreting acoustic scattering in terms of meaningful biological parameters compared with traditional higher frequency approaches and other lower frequency narrowband approaches. Objectives: To conduct a new class of quantitative acoustic studies of scattering by swimbladder-bearing fish utilizing new broadband-acoustic technology that is ... |
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| Seismic Observations and Interpretation in NE China, Infrasound Observations and Interpretation in Utah |
30 Jul 2010 |
133 pages |
| Authors:
Rong M Zhou; Tae S Kim; Relu Burlacu; Brian W Stump; Chris Hayward; Zhi-Xian Yang; Yun-Tai Chen; Robert B Hermann; Stephen Arrowsmith; Kristine Pankow; Sue Nava; Jessie Bonner; Sebastian Hoch; David Whiteman; Aileen Fisher; Ray Kubacki; Mark Leidig; James Britton; David Drobeck; Pete O'Neill; SOUTHERN METHODIST UNIV DALLAS TX
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| A set of fifteen broadband seismic instruments provided to the project by the Program for Array Seismic Studies for Continental Lithosphere (PASSCAL) were deployed in NE China for the purposes of characterizing both the regional structure of the area as well as record local seismic events. During the course of this project the instruments were installed in two separate areas. The first deployment was in and around the Yanqing-Huailai Basin, ... |
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| Wide Area Detection and Identification of Underwater UXO Using Structural Acoustic Senors: 4th Annual Report to SERDP MM-1513 |
21 Jul 2010 |
43 pages |
| Authors:
Joseph A Bucaro; Brian H Houston; Harry Simpson; Michael Saniga; Angie Sarkissian; D Calvo; L Kraus; T Yoder; NAVAL RESEARCH LAB WASHINGTON DC ACOUSTICS DIV
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| This project is exploring the development of a structural acoustics (SA) based sonar methodology for wide area search and identification of underwater unexploded ordnance (UXO). This approach has significant advantages over conventional acoustic approaches relying on formation of high resolution images including: diverse set of fingerprints leading to low false alarm rates; longer range leading to wide area coverage; and low frequency sediment penetration leading to buried target prosecution. A ... |
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| KSC VAB Aeroacoustic Hazard Assessment |
Jul 2010 |
58 pages |
| Authors:
Justin M Oliveira; Sabrina Yedo; Michael D Campbell; Joseph P Atkinson; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION COCOA BEACH FL JOHN F KENNEDY SPACE CENTER
|
| NASA Kennedy Space Center (KSC) carried out an analysis of the effects of aeroacoustics produced by stationary solid rocket motors in processing areas at KSC. In the current paper, attention is directed toward the acoustic effects of a motor burning within the Vehicle Assembly Building (VAB). The analysis was carried out with support from ASRC Aerospace who modeled transmission effects into surrounding facilities. Calculations were done using semi-analytical models for ... |
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| Optics, Acoustics, and Stress in a Nearshore Bottom Nepheloid Layer |
23 Jun 2010 |
7 pages |
| Authors:
Paul S Hill; DALHOUSIE UNIV HALIFAX (NOVA SCOTIA) DEPT OF OCEANOGRAPHY
|
| The goal of this research was to develop greater understanding of the how the flocculation of finegrained sediment responds to turbulent stresses and how this packaging of sediment affects optical and acoustical properties in the water column. OBJECTIVES 1. Quantify the effects of aggregation dynamics on the size distribution of particles in the bottom boundary layer; 2. Quantify how changes in particle packaging affect the optical and acoustical properties of ... |
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| Sonic Gradient Index Lens in Water |
21 Jun 2010 |
|
| Authors:
Theodore P Martin; Michael Nicholas; Gregory J Orris; Liang-Wu Cai; Daniel Torrent; Jose Sanchez-Dehesa; NAVAL RESEARCH LAB WASHINGTON DC ACOUSTICS DIV
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| We study the acoustic scattering properties of a phononic crystal designed to behave as a gradient index lens in water, both experimentally and theoretically. The gradient index lens is designed using a square lattice of stainless-steel cylinders based on a multiple scattering approach in the homogenization limit. We experimentally demonstrate that the lens follows the graded index equations derived for optics by mapping the pressure intensity generated from a spherical ... |
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| The Decibel Report: Acoustic Sound Measurement Modeling and the Effects of Sonar on Marine Mammals |
21 Jun 2010 |
85 pages |
| Authors:
Richard A Katz; Nicholas J Cipriano; David J Pearson; Steve R Dunkleberger; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| This report is an authoritative and comprehensive explanation of sound-level quantities, metrics, and sonar models; its purpose is to provide best available science to acoustics and marine biology subject matter experts, sonar and environmental planners, and policy decision-makers so they can be better informed of the terminology, usage, and practices undertaken for modeling underwater sound energy effects pertinent to U.S. Naval sonar operations and the marine habitat. |
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| Method for Improving Acoustic Impedance of Epoxy Resins |
21 Jun 2010 |
17 pages |
| Authors:
Thomas S Ramotowski; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
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| An epoxy and rubber microcomposite is formed by adding a carboxy-terminated or amine-terminated rubber component having a glass transition temperature less than zero degrees centigrade to a bisphenol A based epoxy resin component; heating the mixture to 150 degrees centigrade; cooling and curing with a suitable curing agent. A phase segregation occurs between the epoxy resin component and the rubber component to form discrete, spherical rubbery domains with the epoxy ... |
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| Characterization of Nonlinear Systems with Memory by Means of Volterra Expansions with Frequency Partitioning: Application to a Cicada Mating Call |
15 Jun 2010 |
58 pages |
| Authors:
Albert H Nuttall; Derke R Hughes; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| This report introduces several new concepts to achieve some alleviation of the curse of dimensionality in determining the higher order kernels in a Volterra expansion. These concepts include: partitioning of the frequency scale(s), the fundamental region of formation, the diagonal strips in the two dimensional frequency space, the second- and third-order basis functions, and filtering of the measured nonlinear output to the particular frequency band under investigation. The equations for ... |
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| Method for Improving Acoustic Impedance of Epoxy Resins |
11 Jun 2010 |
17 pages |
| Authors:
Thomas S Ramotowski; DEPARTMENT OF THE NAVY WASHINGTON DC
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| The present invention is directed to method for producing low modulus acoustically clear polymeric materials. In general, acoustically clear polymeric materials have a low modulus (i.e., stiffness). Examples of these polymeric materials include neoprene, ethylene propylene diene monomer (EPDM) and polyurethane rubbers. Typical applications of these materials encapsulate and protect acoustic projectors and hydrophones from marine environments. In order to function properly in these applications as acoustic windows; the polymeric ... |
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| An Examination of the Feasibility of Ultrasonic Communications Links |
Jun 2010 |
62 pages |
| Authors:
David Tofsted; Sean O'Brien; Sean D'Arcy; Edward Creegan; Scott Elliott; ARMY RESEARCH LAB WHITE SANDS MISSILE RANGE NM COMPUTATIONAL AND INFORMATION SCIENCE DIRECTORATE
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| A study is performed to consider the feasibility of using the ultrasonic band just above the normal adult audio frequency range (20-25 kHz) for low data rate signaling. In this band several features of interest are explored and a potential application (Identification Friend-or-Foe [IFF]) is highlighted. A key finding is that the data transmission rate is restricted in the presence of multipathing effects. Data transmission rates in the 300-baud range ... |
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| Environmental Acoustic Considerations for Passive Detection of Maritime Targets by Hydrophones in a Deep Ocean Trench |
Jun 2010 |
81 pages |
| Authors:
Jeremy S Biediger; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis explores the potential advantage of deep ocean trench placement of an acoustic sensor network. The hypothesis is that a hydrophone deployed in a deep ocean trench will operate in an environment of reduced ambient noise such that passive maritime surveillance may be performed with relatively high signal-to-noise ratio (SNR). Barrier or tripwire coverage along the oceanic trench is made possible by virtue of networked acoustic communication among widely ... |
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| Generating Acoustic Provinces for the U.S. Navy's Low Frequency Bottom Loss Database Using Geographic Information Systems |
Jun 2010 |
4 pages |
| Authors:
Timothy H Ruppel; NAVAL OCEANOGRAPHIC OFFICE STENNIS SPACE CENTER MS ACOUSTIC ANALYSIS BRANCH
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| The U.S. Navy's Low Frequency Bottom Loss (LFBL) database is released and maintained by the Naval Oceanographic Office (NAVOCEANO) and used as an environmental input to many of the Navy-standard tactical decision aids. It is designed to support the Navy's operational requirements in determining the nature of the interaction of 20-1000 Hz acoustic energy with the sea bottom. The general methodology of generating shallow-water LFBL databases was described in a ... |
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| A Metric for Comparing Acoustic Transmission Loss Curves |
Jun 2010 |
7 pages |
| Authors:
J P Fabre; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| A metric is presented for quantifying the difference between two acoustic transmission loss curves. This allows a fast, but more importantly, consistent way to determine how well two underwater acoustic transmission loss curves compare in terms of their end use. Two methods are proposed for different applications, the first involves comparing only the curves themselves and the second involves use of a figure of merit to compare the curves as ... |
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| GOMEX08 - High Frequency Acoustic Propagation over the Alabama Alps |
Jun 2010 |
10 pages |
| Authors:
R L Field; P C Gallacher; D A Hebert; E Jarosz; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| The objective of this work is to diagnose high frequency acoustic propagation directly from oceanographic data and ocean models. To achieve this objective a joint acoustic and oceanographic experiment was performed in the Gulf of Mexico in the summer of 2008. This paper will show that high frequency acoustic propagation at 17.5 kHz tracks the estimated turbulent dissipation rate obtained from field measurements and that ocean modeling gives reasonable estimates ... |
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| Cluster of Sound Speed Fields by an Integral Measure |
Jun 2010 |
6 pages |
| Authors:
James K Fulford; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| A technique to cluster large area oceanic predictions of sound speed into quasi-range independent areas is presented. Oceanic models produce high fidelity predictions of the oceanic sound speed fields that enable large-scale simulation of acoustic propagation with reasonable accuracy. Unfortunately, the oceanic models can produce sound speed fields quicker than can be digested by current technologies in underwater acoustic performance prediction systems. The speed bottleneck can be broken in two ... |
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| Testing and Evaluation of a Dual-Frequency Six-Beam Acoustic Doppler Current Profiler |
Jun 2010 |
3 pages |
| Authors:
Rodney Riley; Eric Stegel; NATIONAL DATA BUOY CENTER STENNIS SPACE CENTER MS
|
| Observations of current velocity in near-surface and near-bottom boundary layers are critically important for many scientific, operational, and engineering applications. NOAA's National Data Buoy Center (NDBC) presently maintains approximately 110 weather and oceanographic buoys. Of these, some are tasked to measure full current profiles , including near-surface currents, in an operational real-time system. Nortek developed a dual-frequency, six-beam acoustic Doppler current profiler to meet the needs of observing the complete ... |
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| EARS Buoy Applications by LADC: II. 3-D Seismic Airgun Array Characterization |
Jun 2010 |
7 pages |
| Authors:
Joal J Newcomb; Arslan M Tashmukhambetov; George E Ioup; Juliette W Ioup; Natalia A Sidorovskaia; James M Stephens; Grayson H Rayborn; Phil Summerfield; NAVAL OCEANOGRAPHY COMMAND STENNIS SPACE CENTER MS
|
| In September 2007 the Littoral Acoustic Demonstration Center (LADC), a consortium of University and Navy scientists, conducted an experiment in the northwest Gulf of Mexico to measure the three-dimensional acoustic field of the primary arrival from a seismic airgun array. The water depth was approximately 1500 m. The acoustic measurements were made by Generation 2 4-channel EARS (Environmental Acoustic Recording System) buoys developed by the Naval Oceanographic Office (NAVOCEANO), with ... |
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| EARS Buoy Applications by LADC: I. Marine Animal Acoustics |
Jun 2010 |
9 pages |
| Authors:
George E Ioup; Juliette W Ioup; Lisa A Pflug; Arslan M Tashmukhambetov; Natalia A Sidorovskaia; Philip Schexnayder; Christopher O Tiemann; Alan Bernstein; Stan A Kuczaj; Grayson H Rayborn; SPACE AND NAVAL WARFARE SYSTEMS CENTER PACIFIC SAN DIEGO CA
|
| Littoral Acoustic Demonstration Center (LADC) scientists have investigated sperm and beaked whale clicks as recorded on Environmental Acoustic Recording System (EARS) buoys to analyze whale behavior and the possibility of identifying individual whales acoustically. The research began in 2001 and continues through the present. LADC has conducted three experiments in the northern Gulf of Mexico and participated with the Naval Undersea Research Centre with three experiments in the Ligurian Sea. ... |
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| Effects of Hurricanes on Ambient Noise in the Gulf of Mexico |
Jun 2010 |
9 pages |
| Authors:
Mark A Snyder; NAVAL OCEANOGRAPHIC OFFICE STENNIS SPACE CENTER MS
|
| Long-term omni-directional ambient noise was collected at several sites in the Gulf of Mexico during 2004 and 2005. The Naval Oceanographic Office deployed bottom-moored Environmental Acoustic Recording System (EARS) buoys approximately 159 nautical miles south of Panama City, Florida, in water depths of 3200 meters. The hydrophone of each buoy was 265 meters above the bottom. The buoys were located near a major shipping lane, with an estimated 1.5 to ... |
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| Coverage Metric for Acoustic Receiver Evaluation and Track Generation |
Jun 2010 |
6 pages |
| Authors:
Steven M Dennis; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Acoustic receiver track generation has been the subject of active research, both academic and operational, since at least 1946. In general, track generation algorithms operate by maximizing some measure of effectiveness or performance for a particular receiver in a particular environment. Current probability-based receiver performance measures are difficult to visualize, time consuming to calculate and are not easily subject to strict scientific analysis. Although great strides have been made in ... |
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| Potential Impact of Long-Life Environmental Sonobuoys on Littoral ASW |
Jun 2010 |
4 pages |
| Authors:
Donald R DelBalzo; Joseph Klicka; NAVAL AIR SYSTEMS COMMAND PATUXENT RIVER MD
|
| The focus of military activity has recently shifted from large area engagements to regional conflicts. Consequently, supportive Naval maritime operations have continued to evolve toward littoral warfare in complicated shallow-water, near-shore environments. This evolution requires new sensors, advanced Concept of Operations, and improved data-analysis capabilities, among others. Planning operations in these harsh-environment areas is difficult because accurate predictions of tactical sensor performance depend on detailed knowledge of the local environmental ... |
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| Technical Metrics for Acoustic Evaluation |
Jun 2010 |
6 pages |
| Authors:
J P Fabre; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| A Technical Metrics Workshop was held at NRL Stennis Space Center, MS, by the NRL Acoustics Division April 29 - May 1, 2008. The primary goal of the workshop was to identify the state-of-the-art technical and scientific metrics for the acoustic and oceanographic research and development communities. A second goal was to relate scientific metrics to engineering and performance metrics, and outline the inclusion of uncertainties in various parameters using ... |
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| Weakly Nonlinear Harmonic Acoustic Waves in Classical Thermoviscous Fluids: A Perturbation Analysis |
Jun 2010 |
5 pages |
| Authors:
P M Jordan; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Using regular perturbation analysis, we investigate the propagation of a time-harmonic acoustic signal, generated by a sinusoidal boundary condition, in a half-space filled with a classical thermoviscous fluid. It is assumed that the flow is described by a recently introduced, weakly nonlinear partial differential equation (PDE) that, unlike earlier models, exhibits a Hamiltonian structure in the lossless limit. |
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| Optimizations for Fourier Synthesized Time Domain Pulse Propagation Calculations |
Jun 2010 |
5 pages |
| Authors:
Robert A Zingarelli; Stanley A Chin-Bing; Michael D Collins; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| Fourier transform methods are the standard way for determining time-domain pulse structure and arrival time from a set of continuous wave (discrete frequency) underwater acoustic model calculations. This technique requires a large number of computer model runs at closely spaced frequencies, often making it computationally expensive. It has the advantages of including the correct attenuation at each frequency component, and of correctly treating continuity requirements at the water/sediment interface. Direct ... |
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| Statistical Space-Time-Frequency Characterization of MIMO Shallow Water Acoustic Channels |
Jun 2010 |
7 pages |
| Authors:
Alenka G Zajic; NAVAL RESEARCH LAB WASHINGTON DC
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| This paper proposes a geometry-based statistical model for multiple-input multiple-output shallow water acoustic multipath fading channels. From the reference model, the corresponding space-time-frequency correlation function is derived. Finally, the derived spatial and temporal correlations are compared with the empirically obtained channel statistics and close agreement is observed. |
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| Laboratory Measurements of Multi-Frequency and Broadband Acoustic Scattering from Turbulent and Double-Diffusive Microstructure. High-Frequency Broadband Acoustic Scattering from Non-Linear Internal Waves during SW06 |
27 May 2010 |
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| Authors:
Andone C Lavery; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
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| The long-term goal of this research is to understand high-frequency broadband acoustic backscattering from small-scale physical processes, such as internal waves, turbulence, and microstructure, in shallow, stratified coastal waters. The primary objective of the proposed research was to measure high-frequency broadband acoustic backscattering in highly stratified, energetic environments and to determine the contribution to scattering from temperature and salinity microstructure. Testing the validity of existing scattering models and the initial ... |
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| Remote Sensing of Temperature and Salinity Microstructure in Rivers and Estuaries Using Broadband Acoustic Scattering Techniques |
26 May 2010 |
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| Authors:
Andone C Lavery; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
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| The long-term goals of this research are to 1) measure and understand high-frequency broadband acoustic scattering in rivers and estuaries characterized by strong temperature and salinity gradients and intermittent, high dissipation rates of turbulent kinetic energy, and 2) use these measurements and understanding to develop a remote sensing tool for quantifying the structure of stratified turbulence. |
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Acoustics
