First Annual Progress Report on Transmission of Information by Acoustic Communication along Metal Pathways in Nuclear Facilities

Energy Technology Data Exchange (ETDEWEB)

Heifetz, A. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Bakhtiari, S. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Huang, X. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Ponciroli, R. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Vilim, R. B. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

2017-09-30

The objective of this project is to develop and demonstrate methods for transmission of information in nuclear facilities by acoustic means along existing in-place metal piping infrastructure. Pipes are omnipresent in a nuclear facility, and penetrate enclosures and partitions, such as the containment building wall. In the envisioned acoustic communication (AC) system, packets of information will be transmitted as guided acoustic waves along pipes. Performance of AC hardware and network protocols for efficient and secure communications under development in this project will be eventually evaluated in a representative nuclear power plant environment. Research efforts in the first year of this project have been focused on identification of appropriate transducers, and evaluation of their performance for information transmission along nuclear-grade metallic pipes. COMSOL computer simulations were performed to study acoustic wave generation, propagation, and attenuation on pipes. An experimental benchtop system was used to evaluate signal attenuation and spectral dispersion using piezo-electric transducers (PZTs) and electromagnetic acoustic transducers (EMATs). Communication protocols under evaluation consisted on-off keying (OOK) signal modulation, in particular amplitude shift keying (ASK) and phase shift keying (PSK). Tradeoffs between signal power and communication data rate were considered for ASK and PSK coding schemes.

OFDM for underwater acoustic communications

CERN Document Server

Zhou, Shengli

2014-01-01

A blend of introductory material and advanced signal processing and communication techniques, of critical importance to underwater system and network development This book, which is the first to describe the processing techniques central to underwater OFDM, is arranged into four distinct sections: First, it describes the characteristics of underwater acoustic channels, and stresses the difference from wireless radio channels. Then it goes over the basics of OFDM and channel coding. The second part starts with an overview of the OFDM receiver, and develops various modules for the receiver des

Call transmission efficiency in native and invasive anurans: competing hypotheses of divergence in acoustic signals.

Science.gov (United States)

Llusia, Diego; Gómez, Miguel; Penna, Mario; Márquez, Rafael

2013-01-01

Invasive species are a leading cause of the current biodiversity decline, and hence examining the major traits favouring invasion is a key and long-standing goal of invasion biology. Despite the prominent role of the advertisement calls in sexual selection and reproduction, very little attention has been paid to the features of acoustic communication of invasive species in nonindigenous habitats and their potential impacts on native species. Here we compare for the first time the transmission efficiency of the advertisement calls of native and invasive species, searching for competitive advantages for acoustic communication and reproduction of introduced taxa, and providing insights into competing hypotheses in evolutionary divergence of acoustic signals: acoustic adaptation vs. morphological constraints. Using sound propagation experiments, we measured the attenuation rates of pure tones (0.2-5 kHz) and playback calls (Lithobates catesbeianus and Pelophylax perezi) across four distances (1, 2, 4, and 8 m) and over two substrates (water and soil) in seven Iberian localities. All factors considered (signal type, distance, substrate, and locality) affected transmission efficiency of acoustic signals, which was maximized with lower frequency sounds, shorter distances, and over water surface. Despite being broadcast in nonindigenous habitats, the advertisement calls of invasive L. catesbeianus were propagated more efficiently than those of the native species, in both aquatic and terrestrial substrates, and in most of the study sites. This implies absence of optimal relationship between native environments and propagation of acoustic signals in anurans, in contrast to what predicted by the acoustic adaptation hypothesis, and it might render these vertebrates particularly vulnerable to intrusion of invasive species producing low frequency signals, such as L. catesbeianus. Our findings suggest that mechanisms optimizing sound transmission in native habitat can play a less

Call transmission efficiency in native and invasive anurans: competing hypotheses of divergence in acoustic signals.

Directory of Open Access Journals (Sweden)

Diego Llusia

Full Text Available Invasive species are a leading cause of the current biodiversity decline, and hence examining the major traits favouring invasion is a key and long-standing goal of invasion biology. Despite the prominent role of the advertisement calls in sexual selection and reproduction, very little attention has been paid to the features of acoustic communication of invasive species in nonindigenous habitats and their potential impacts on native species. Here we compare for the first time the transmission efficiency of the advertisement calls of native and invasive species, searching for competitive advantages for acoustic communication and reproduction of introduced taxa, and providing insights into competing hypotheses in evolutionary divergence of acoustic signals: acoustic adaptation vs. morphological constraints. Using sound propagation experiments, we measured the attenuation rates of pure tones (0.2-5 kHz and playback calls (Lithobates catesbeianus and Pelophylax perezi across four distances (1, 2, 4, and 8 m and over two substrates (water and soil in seven Iberian localities. All factors considered (signal type, distance, substrate, and locality affected transmission efficiency of acoustic signals, which was maximized with lower frequency sounds, shorter distances, and over water surface. Despite being broadcast in nonindigenous habitats, the advertisement calls of invasive L. catesbeianus were propagated more efficiently than those of the native species, in both aquatic and terrestrial substrates, and in most of the study sites. This implies absence of optimal relationship between native environments and propagation of acoustic signals in anurans, in contrast to what predicted by the acoustic adaptation hypothesis, and it might render these vertebrates particularly vulnerable to intrusion of invasive species producing low frequency signals, such as L. catesbeianus. Our findings suggest that mechanisms optimizing sound transmission in native habitat

Noise can affect acoustic communication and subsequent spawning success in fish.

Science.gov (United States)

de Jong, Karen; Amorim, M Clara P; Fonseca, Paulo J; Fox, Clive J; Heubel, Katja U

2018-06-01

There are substantial concerns that increasing levels of anthropogenic noise in the oceans may impact aquatic animals. Noise can affect animals physically, physiologically and behaviourally, but one of the most obvious effects is interference with acoustic communication. Acoustic communication often plays a crucial role in reproductive interactions and over 800 species of fish have been found to communicate acoustically. There is very little data on whether noise affects reproduction in aquatic animals, and none in relation to acoustic communication. In this study we tested the effect of continuous noise on courtship behaviour in two closely-related marine fishes: the two-spotted goby (Gobiusculus flavescens) and the painted goby (Pomatoschistus pictus) in aquarium experiments. Both species use visual and acoustic signals during courtship. In the two-spotted goby we used a repeated-measures design testing the same individuals in the noise and the control treatment, in alternating order. For the painted goby we allowed females to spawn, precluding a repeated-measures design, but permitting a test of the effect of noise on female spawning decisions. Males of both species reduced acoustic courtship, but only painted gobies also showed less visual courtship in the noise treatment compared to the control. Female painted gobies were less likely to spawn in the noise treatment. Thus, our results provide experimental evidence for negative effects of noise on acoustic communication and spawning success. Spawning is a crucial component of reproduction. Therefore, even though laboratory results should not be extrapolated directly to field populations, our results suggest that reproductive success may be sensitive to noise pollution, potentially reducing fitness. Copyright © 2017 Elsevier Ltd. All rights reserved.

Acoustic signal analysis in the creeping discharge

International Nuclear Information System (INIS)

Nakamiya, T; Sonoda, Y; Tsuda, R; Ebihara, K; Ikegami, T

2008-01-01

We have previously succeeded in measuring the acoustic signal due to the dielectric barrier discharge and discriminating the dominant frequency components of the acoustic signal. The dominant frequency components appear over 20kHz of acoustic signal by the dielectric barrier discharge. Recently surface discharge control technology has been focused from practical applications such as ozonizer, NO X reactors, light source or display. The fundamental experiments are carried to examine the creeping discharge using the acoustic signal. When the high voltage (6kV, f = 10kHz) is applied to the electrode, the discharge current flows and the acoustic sound is generated. The current, voltage waveforms of creeping discharge and the sound signal detected by the condenser microphone are stored in the digital memory scope. In this scheme, Continuous Wavelet Transform (CWT) is applied to discriminate the acoustic sound of the micro discharge and the dominant frequency components are studied. CWT results of sound signal show the frequency spectrum of wideband up to 100kHz. In addition, the energy distributions of acoustic signal are examined by CWT

Auditory selectivity for the acoustic properties of conspecific mate-attracting signals in lower vertebrates and songbirds

OpenAIRE

Gerhardt, Carl

2015-01-01

H Carl GerhardtDivision of Biological Sciences, University of Missouri, Columbia, MO, USAAbstract: The interplay between conspecific senders and receivers both maintains the usual species specificity of acoustic communication and yet offers the potential for speciation provided that signals and preferences change in a parallel or coupled way. Acoustic signals commonly function in mate attraction and contribute to reproductive success. Such signals are especially prevalent in some lower verteb...

Hot topics: Signal processing in acoustics

Science.gov (United States)

Gaumond, Charles F.

2005-09-01

Signal processing in acoustics is a multidisciplinary group of people that work in many areas of acoustics. We have chosen two areas that have shown exciting new applications of signal processing to acoustics or have shown exciting and important results from the use of signal processing. In this session, two hot topics are shown: the use of noiselike acoustic fields to determine sound propagation structure and the use of localization to determine animal behaviors. The first topic shows the application of correlation on geo-acoustic fields to determine the Greens function for propagation through the Earth. These results can then be further used to solve geo-acoustic inverse problems. The first topic also shows the application of correlation using oceanic noise fields to determine the Greens function through the ocean. These results also have utility for oceanic inverse problems. The second topic shows exciting results from the detection, localization, and tracking of marine mammals by two different groups. Results from detection and localization of bullfrogs are shown, too. Each of these studies contributed to the knowledge of animal behavior. [Work supported by ONR.

Energy scavenging system by acoustic wave and integrated wireless communication

Science.gov (United States)

Kim, Albert

The purpose of the project was developing an energy-scavenging device for other bio implantable devices. Researchers and scientist have studied energy scavenging method because of the limitation of traditional power source, especially for bio-implantable devices. In this research, piezoelectric power generator that activates by acoustic wave, or music was developed. Follow by power generator, a wireless communication also integrated with the device for monitoring the power generation. The Lead Zirconate Titanate (PZT) bimorph cantilever with a proof mass at the free end tip was studied to convert acoustic wave to power. The music or acoustic wave played through a speaker to vibrate piezoelectric power generator. The LC circuit integrated with the piezoelectric material for purpose of wireless monitoring power generation. However, wireless monitoring can be used as wireless power transmission, which means the signal received via wireless communication also can be used for power for other devices. Size of 74 by 7 by 7cm device could generate and transmit 100mVp from 70 mm distance away with electrical resonant frequency at 420.2 kHz..

Processing of acoustic signal in rock desintegration

Directory of Open Access Journals (Sweden)

Futó Jozef

2002-12-01

Full Text Available For the determination of an effective rock disintegration for a given tool and rock type it is needed to define an optimal disintegration regime. Optimisation of the disintegration process by drilling denotes the finding out an appropriate couple of input parameters of disintegration, i.e. the thrust and revolutions for a quasi-equal rock environment. The disintegration process can be optimised to reach the maximum immediate drilling rate, to reach the minimum specific disintegration energy or to reach the maximum ratio of immediate drilling rate and specific disintegration energy. For the determination of the optimal thrust and revolutions it is needed to monitor the disintegration process. Monitoring of the disintegration process in real conditions is complicated by unfavourable factors, such as the presence of water, dust, vibrations etc. Following our present experience in the monitoring of drilling or full-profile driving, we try to replace the monitoring of input values by monitoring of the scanned acoustic signal. This method of monitoring can extend the optimisation of disintegration process in the technical practice. Its advantage consists in the registration of one acoustic signal by an appropriate microphone. Monitoring of acoustic signal is used also in monitoring of metal machining by milling and turning jobs. The research results of scanning of the acoustic signal in machining of metals are encouraging. Acoustic signal can be processed by different statistical parameters. The paper decribes some results of monitoring of the acoustic signal in rock disintegration on the drilling stand of the Institute of Geotechnics SAS in Košice. The acoustic signal has been registered and processed in no-load run of electric motor, in no-load run of electric motor with a drilling fluid, and in the Ruskov andesite drilling. Registration and processing of the acoustic signal is solved as a part of the research grant task within the basic research

Time reversal signal processing in acoustic emission testing

Czech Academy of Sciences Publication Activity Database

Převorovský, Zdeněk; Krofta, Josef; Kober, Jan; Dvořáková, Zuzana; Chlada, Milan; Dos Santos, S.

2014-01-01

Roč. 19, č. 12 (2014) ISSN 1435-4934. [European Conference on Non-Destructive Testing (ECNDT 2014) /11./. Praha, 06.10.2014-10.10.2014] Institutional support: RVO:61388998 Keywords : acoustic emission (AE) * ultrasonic testing (UT) * signal processing * source location * time reversal acoustic s * acoustic emission * signal processing and transfer Subject RIV: BI - Acoustic s http://www.ndt.net/events/ECNDT2014/app/content/Slides/637_Prevorovsky.pdf

Acoustic communication for Maya Autonomous Underwater Vehicle - performance evaluation of acoustic modem

Digital Repository Service at National Institute of Oceanography (India)

Afzulpurkar, S.; Maurya, P.; Navelkar, G.S.; Desa, E.S.; Mascarenhas, A.A.M.Q.; Dabholkar, N.A.; Madhan, R.; Prabhudesai, S.P.

traffic. This necessitates monitoring the AUV status and data quality through an acoustic link which needs to perform reliably under such conditions, at long range. To address these situations partially, acoustic communication capability is planned...

Simulated performance of an acoustic modem using phase-modulated signals in a time-varying, shallow-water environment

DEFF Research Database (Denmark)

Bjerrum-Niese, Christian; Jensen, Leif Bjørnø

1996-01-01

and dynamic multipath channel. Multipath arrivals at the receiver cause phase distortion and fading of the signal envelope. Yet, for extreme ratios of range to depth, the delays of multipath arrivals decrease, and the channel impulse response coherently contributes energy to the signal at short delays......Underwater acoustic modems using coherent modulation, such as phase-shift keying, have proven to efficiently exploit the bandlimited underwater acoustical communication channel. However, the performance of an acoustic modem, given as maximum range and data and error rate, is limited in the complex...... relative to the first arrival, while longer delays give rise to intersymbol interference. Following this, the signal-to-multipath ratio (SMR) is introduced. It is claimed that the SMR determines the performance rather than the signal-to-noise ratio (SNR). Using a ray model including temporal variations...

Signal classification for acoustic neutrino detection

International Nuclear Information System (INIS)

Neff, M.; Anton, G.; Enzenhöfer, A.; Graf, K.; Hößl, J.; Katz, U.; Lahmann, R.; Richardt, C.

2012-01-01

This article focuses on signal classification for deep-sea acoustic neutrino detection. In the deep sea, the background of transient signals is very diverse. Approaches like matched filtering are not sufficient to distinguish between neutrino-like signals and other transient signals with similar signature, which are forming the acoustic background for neutrino detection in the deep-sea environment. A classification system based on machine learning algorithms is analysed with the goal to find a robust and effective way to perform this task. For a well-trained model, a testing error on the level of 1% is achieved for strong classifiers like Random Forest and Boosting Trees using the extracted features of the signal as input and utilising dense clusters of sensors instead of single sensors.

Acoustic MIMO signal processing

CERN Document Server

Huang, Yiteng; Chen, Jingdong

2006-01-01

A timely and important book addressing a variety of acoustic signal processing problems under multiple-input multiple-output (MIMO) scenarios. It uniquely investigates these problems within a unified framework offering a novel and penetrating analysis.

Acoustic MIMO communications in a very shallow water channel

Science.gov (United States)

Zhou, Yuehai; Cao, Xiuling; Tong, Feng

2015-12-01

Underwater acoustic channels pose significant difficulty for the development of high speed communication due to highly limited band-width as well as hostile multipath interference. Enlightened by rapid progress of multiple input multiple output (MIMO) technologies in wireless communication scenarios, MIMO systems offer a potential solution by enabling multiple spatially parallel communication channels to improve communication performance as well as capacity. For MIMO acoustic communications, deep sea channels offer substantial spatial diversity among multiple channels that can be exploited to address simultaneous multipath and co-channel interference. At the same time, there are increasing requirements for high speed underwater communication in very shallow water area (for example, a depth less than 10 m). In this paper, a space-time multichannel adaptive receiver consisting of multiple decision feedback equalizers (DFE) is adopted as the receiver for a very shallow water MIMO acoustic communication system. The performance of multichannel DFE receivers with relatively small number of receiving elements are analyzed and compared with that of the multichannel time reversal receiver to evaluate the impact of limited spatial diversity on multi-channel equalization and time reversal processing. The results of sea trials in a very shallow water channel are presented to demonstrate the feasibility of very shallow water MIMO acoustic communication.

Acoustic Localization with Infrasonic Signals

Science.gov (United States)

Threatt, Arnesha; Elbing, Brian

2015-11-01

Numerous geophysical and anthropogenic events emit infrasonic frequencies (<20 Hz), including volcanoes, hurricanes, wind turbines and tornadoes. These sounds, which cannot be heard by the human ear, can be detected from large distances (in excess of 100 miles) due to low frequency acoustic signals having a very low decay rate in the atmosphere. Thus infrasound could be used for long-range, passive monitoring and detection of these events. An array of microphones separated by known distances can be used to locate a given source, which is known as acoustic localization. However, acoustic localization with infrasound is particularly challenging due to contamination from other signals, sensitivity to wind noise and producing a trusted source for system development. The objective of the current work is to create an infrasonic source using a propane torch wand or a subwoofer and locate the source using multiple infrasonic microphones. This presentation will present preliminary results from various microphone configurations used to locate the source.

Registration and processing of acoustic signal in rock drilling

Directory of Open Access Journals (Sweden)

Futó Jozef

2002-03-01

Full Text Available For the determination of an effective rock disintegration for a given tool and rock type it is needed to define an optimal disintegration regime. Optimisation of the disintegration process by drilling denotes the finding out an appropriate couple of input parameters of disintegration, i.e. the thrust and revolutions for a quasi-equal rock environment. The disintegration process can be optimised to reach the maximum immediate drilling rate, to reach the minimum specific disintegration energy or to reach the maximum ratio of immediate drilling rate and specific disintegration energy. For the determination of the optimal thrust and revolutions it is needed to monitor the disintegration process. Monitoring of the disintegration process in real conditions is complicated by unfavourable factors, such as the presence of water, dust, vibrations etc. Following our present experience in the monitoring of drilling or full-profile driving, we try to replace the monitoring of input values by monitoring of the scanned acoustic signal. This method of monitoring can extend the optimisation of disintegration process in the technical practice. Its advantage consists in the registration of one acoustic signal by an appropriate microphone. Monitoring of acoustic signal is used also in monitoring of metal machining by milling and turning jobs. The research results of scanning of the acoustic signal in machining of metals are encouraging. Acoustic signal can be processed by different statistical parameters. The paper decribes some results of monitoring of the acoustic signal in rock disintegration on the drilling stand of the Institute of Geotechnics SAS in Košice. The acoustic signal has been registered and processed in no-load run of electric motor, in no-load run of electric motor with a drilling fluid, and in the Ruskov andesite drilling. Registration and processing of the acoustic signal is solved as a part of the research grant task within the basic research

Cooperative OFDM underwater acoustic communications

CERN Document Server

Cheng, Xilin; Cheng, Xiang

2016-01-01

Following underwater acoustic channel modeling, this book investigates the relationship between coherence time and transmission distances. It considers the power allocation issues of two typical transmission scenarios, namely short-range transmission and medium-long range transmission. For the former scenario, an adaptive system is developed based on instantaneous channel state information. The primary focus is on cooperative dual-hop orthogonal frequency division multiplexing (OFDM). This book includes the decomposed fountain codes designed to enable reliable communications with higher energy efficiency. It covers the Doppler Effect, which improves packet transmission reliability for effective low-complexity mirror-mapping-based intercarrier interference cancellation schemes capable of suppressing the intercarrier interference power level. Designed for professionals and researchers in the field of underwater acoustic communications, this book is also suitable for advanced-level students in electrical enginee...

Department of Cybernetic Acoustics

Science.gov (United States)

The development of the theory, instrumentation and applications of methods and systems for the measurement, analysis, processing and synthesis of acoustic signals within the audio frequency range, particularly of the speech signal and the vibro-acoustic signal emitted by technical and industrial equipments treated as noise and vibration sources was discussed. The research work, both theoretical and experimental, aims at applications in various branches of science, and medicine, such as: acoustical diagnostics and phoniatric rehabilitation of pathological and postoperative states of the speech organ; bilateral ""man-machine'' speech communication based on the analysis, recognition and synthesis of the speech signal; vibro-acoustical diagnostics and continuous monitoring of the state of machines, technical equipments and technological processes.

Catecholaminergic contributions to vocal communication signals.

Science.gov (United States)

Matheson, Laura E; Sakata, Jon T

2015-05-01

Social context affects behavioral displays across a variety of species. For example, social context acutely influences the acoustic and temporal structure of vocal communication signals such as speech and birdsong. Despite the prevalence and importance of such social influences, little is known about the neural mechanisms underlying the social modulation of communication. Catecholamines are implicated in the regulation of social behavior and motor control, but the degree to which catecholamines influence vocal communication signals remains largely unknown. Using a songbird, the Bengalese finch, we examined the extent to which the social context in which song is produced affected immediate early gene expression (EGR-1) in catecholamine-synthesising neurons in the midbrain. Further, we assessed the degree to which administration of amphetamine, which increases catecholamine concentrations in the brain, mimicked the effect of social context on vocal signals. We found that significantly more catecholaminergic neurons in the ventral tegmental area and substantia nigra (but not the central grey, locus coeruleus or subcoeruleus) expressed EGR-1 in birds that were exposed to females and produced courtship song than in birds that produced non-courtship song in isolation. Furthermore, we found that amphetamine administration mimicked the effects of social context and caused many aspects of non-courtship song to resemble courtship song. Specifically, amphetamine increased the stereotypy of syllable structure and sequencing, the repetition of vocal elements and the degree of sequence completions. Taken together, these data highlight the conserved role of catecholamines in vocal communication across species, including songbirds and humans. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Wavelet-based ground vehicle recognition using acoustic signals

Science.gov (United States)

Choe, Howard C.; Karlsen, Robert E.; Gerhart, Grant R.; Meitzler, Thomas J.

1996-03-01

We present, in this paper, a wavelet-based acoustic signal analysis to remotely recognize military vehicles using their sound intercepted by acoustic sensors. Since expedited signal recognition is imperative in many military and industrial situations, we developed an algorithm that provides an automated, fast signal recognition once implemented in a real-time hardware system. This algorithm consists of wavelet preprocessing, feature extraction and compact signal representation, and a simple but effective statistical pattern matching. The current status of the algorithm does not require any training. The training is replaced by human selection of reference signals (e.g., squeak or engine exhaust sound) distinctive to each individual vehicle based on human perception. This allows a fast archiving of any new vehicle type in the database once the signal is collected. The wavelet preprocessing provides time-frequency multiresolution analysis using discrete wavelet transform (DWT). Within each resolution level, feature vectors are generated from statistical parameters and energy content of the wavelet coefficients. After applying our algorithm on the intercepted acoustic signals, the resultant feature vectors are compared with the reference vehicle feature vectors in the database using statistical pattern matching to determine the type of vehicle from where the signal originated. Certainly, statistical pattern matching can be replaced by an artificial neural network (ANN); however, the ANN would require training data sets and time to train the net. Unfortunately, this is not always possible for many real world situations, especially collecting data sets from unfriendly ground vehicles to train the ANN. Our methodology using wavelet preprocessing and statistical pattern matching provides robust acoustic signal recognition. We also present an example of vehicle recognition using acoustic signals collected from two different military ground vehicles. In this paper, we will

Performance analysis of passive time reversal communication technique for multipath interference in shallow sea acoustic channel

Science.gov (United States)

Kida, Yukihiro; Shimura, Takuya; Deguchi, Mitsuyasu; Watanabe, Yoshitaka; Ochi, Hiroshi; Meguro, Koji

2017-07-01

In this study, the performance of passive time reversal (PTR) communication techniques in multipath rich underwater acoustic environments is investigated. It is recognized empirically and qualitatively that a large number of multipath arrivals could generally raise the demodulation result of PTR. However, the relationship between multipath and the demodulation result is hardly evaluated quantitatively. In this study, the efficiency of the PTR acoustic communication techniques for multipath interference cancelation was investigated quantitatively by applying a PTR-DFE (decision feed-back filter) scheme to a synthetic dataset of a horizontal underwater acoustic channel. Mainly, in this study, we focused on the relationship between the signal-to-interference ratio (SIR) of datasets and the output signal-to-noise ratio (OSNR) of demodulation results by a parametric study approach. As a result, a proportional relation between SIR and OSNR is confirmed in low-SNR datasets. It was also found that PTR has a performance limitation, that is OSNR converges to a typical value depending on the number of receivers. In conclusion, results indicate that PTR could utilize the multipath efficiently and also withstand the negative effects of multipath interference at a given limitation.

Locality of Area Coverage on Digital Acoustic Communication in Air using Differential Phase Shift Keying

Science.gov (United States)

Mizutani, Keiichi; Ebihara, Tadashi; Wakatsuki, Naoto; Mizutani, Koichi

2009-07-01

We experimentally evaluate the locality of digital acoustic communication in air. Digital acoustic communication in air is suitable for a small cell system, because acoustic waves have a short propagation distance in air. In this study, optimal cell size is experimentally evaluated. Each base station (BS) transmits different commands. In our experiment, differential phase shift keying (DPSK), especially binary DPSK (DBPSK), is adopted as a modulation and demodulation scheme. The evaluated system consists of a personal computer (PC), a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), a loud speaker (SP), a microphone (MIC), and transceiver software. All experiments are performed in an anechoic room. The cell size of the transmitter can be limited under low signal-to-noise ratio (SNR) condition. If another transmitter works, cell size is limited by the effect of the interference from that transmitter. The cell size-to-distance ratio of transmitter A to transmitter B is 37.5%, if cell edge bit-error-rate (BER) is taken as 10-3.

Elevated stress hormone diminishes the strength of female preferences for acoustic signals in the green treefrog.

Science.gov (United States)

Davis, A Gabriell; Leary, Christopher J

2015-03-01

Mate selection can be stressful; time spent searching for mates can increase predation risk and/or decrease food consumption, resulting in elevated stress hormone levels. Both high predation risk and low food availability are often associated with increased variation in mate choice by females, but it is not clear whether stress hormone levels contribute to such variation in female behavior. We examined how the stress hormone corticosterone (CORT) affects female preferences for acoustic signals in the green treefrog, Hyla cinerea. Specifically, we assessed whether CORT administration affects female preferences for call rate - an acoustic feature that is typically under directional selection via mate choice by females in most anurans and other species that communicate using acoustic signals. Using a dual speaker playback paradigm, we show that females that were administered higher doses of CORT were less likely to choose male advertisement calls broadcast at high rates. Neither CORT dose nor level was related to the latency of female phonotactic responses, suggesting that elevated CORT does not influence the motivation to mate. Results were also not related to circulating sex steroids (i.e., progesterone, androgens or estradiol) that have traditionally been the focus of studies examining the hormonal basis for variation in female mate choice. Our results thus indicate that elevated CORT levels decrease the strength of female preferences for acoustic signals. Copyright © 2015 Elsevier Inc. All rights reserved.

Acoustic Signals in Domestic Chicken (Gallus gallus): A Tool for ...

African Journals Online (AJOL)

of the chicken model in teaching acoustic communication, animal behavior and the ... commercial laying strains so it is not important in intensive poultry husbandry ... And to introduce students to acoustic lab and explore some aspects of ...

Low complexity adaptive equalizers for underwater acoustic communications

Science.gov (United States)

Soflaei, Masoumeh; Azmi, Paeiz

2014-08-01

Interference signals due to scattering from surface and reflecting from bottom is one of the most important problems of reliable communications in shallow water channels. To solve this problem, one of the best suggested ways is to use adaptive equalizers. Convergence rate and misadjustment error in adaptive algorithms play important roles in adaptive equalizer performance. In this paper, affine projection algorithm (APA), selective regressor APA(SR-APA), family of selective partial update (SPU) algorithms, family of set-membership (SM) algorithms and selective partial update selective regressor APA (SPU-SR-APA) are compared with conventional algorithms such as the least mean square (LMS) in underwater acoustic communications. We apply experimental data from the Strait of Hormuz for demonstrating the efficiency of the proposed methods over shallow water channel. We observe that the values of the steady-state mean square error (MSE) of SR-APA, SPU-APA, SPU-normalized least mean square (SPU-NLMS), SPU-SR-APA, SM-APA and SM-NLMS algorithms decrease in comparison with the LMS algorithm. Also these algorithms have better convergence rates than LMS type algorithm.

Acoustic communication in the Greater Sage-Grouse (Centrocercus urophasianus) an examination into vocal sacs, sound propagation, and signal directionality

Science.gov (United States)

Dantzker, Marc Steven

The thesis is an inquiry into the acoustic communication of a very unusual avian species, the Greater Sage-Grouse, Centrocercus urophasianus. One of the most outstanding features of this animal's dynamic mating display is its use of paired air sacs that emerge explosively from an esophageal pouch. My first line of inquiry into this system is a review of the form and function of similar vocal apparatuses, collectively called vocal sacs, in birds. Next, with a combination of mathematical models and field measurements, My collaborator and I investigate the acoustic environment where the Greater Sage-Grouse display. The complexities of this acoustic environment are relevant both to the birds and to the subsequent examinations of the display's properties. Finally, my collaborators and I examine a cryptic component of the acoustic display --- directionality --- which we measured simultaneously from multiple locations around free moving grouse on their mating grounds.

Acoustic communication at the water's edge: evolutionary insights from a mudskipper.

Directory of Open Access Journals (Sweden)

Gianluca Polgar

Full Text Available Coupled behavioural observations and acoustical recordings of aggressive dyadic contests showed that the mudskipper Periophthalmodon septemradiatus communicates acoustically while out of water. An analysis of intraspecific variability showed that specific acoustic components may act as tags for individual recognition, further supporting the sounds' communicative value. A correlative analysis amongst acoustical properties and video-acoustical recordings in slow-motion supported first hypotheses on the emission mechanism. Acoustic transmission through the wet exposed substrate was also discussed. These observations were used to support an "exaptation hypothesis", i.e. the maintenance of key adaptations during the first stages of water-to-land vertebrate eco-evolutionary transitions (based on eco-evolutionary and palaeontological considerations, through a comparative bioacoustic analysis of aquatic and semiterrestrial gobiid taxa. In fact, a remarkable similarity was found between mudskipper vocalisations and those emitted by gobioids and other soniferous benthonic fishes.

Signal processing for passive detection and classification of underwater acoustic signals

Science.gov (United States)

Chung, Kil Woo

2011-12-01

This dissertation examines signal processing for passive detection, classification and tracking of underwater acoustic signals for improving port security and the security of coastal and offshore operations. First, we consider the problem of passive acoustic detection of a diver in a shallow water environment. A frequency-domain multi-band matched-filter approach to swimmer detection is presented. The idea is to break the frequency contents of the hydrophone signals into multiple narrow frequency bands, followed by time averaged (about half of a second) energy calculation over each band. Then, spectra composed of such energy samples over the chosen frequency bands are correlated to form a decision variable. The frequency bands with highest Signal/Noise ratio are used for detection. The performance of the proposed approach is demonstrated for experimental data collected for a diver in the Hudson River. We also propose a new referenceless frequency-domain multi-band detector which, unlike other reference-based detectors, does not require a diver specific signature. Instead, our detector matches to a general feature of the diver spectrum in the high frequency range: the spectrum is roughly periodic in time and approximately flat when the diver exhales. The performance of the proposed approach is demonstrated by using experimental data collected from the Hudson River. Moreover, we present detection, classification and tracking of small vessel signals. Hydroacoustic sensors can be applied for the detection of noise generated by vessels, and this noise can be used for vessel detection, classification and tracking. This dissertation presents recent improvements aimed at the measurement and separation of ship DEMON (Detection of Envelope Modulation on Noise) acoustic signatures in busy harbor conditions. Ship signature measurements were conducted in the Hudson River and NY Harbor. The DEMON spectra demonstrated much better temporal stability compared with the full ship

A GPS-free passive acoustic localization scheme for underwater wireless sensor networks

KAUST Repository

Mirza, Mohammed; Shakir, Muhammad; Alouini, Mohamed-Slim

2011-01-01

Seaweb is an acoustic communication technology that enables communication between sensor nodes. Seaweb interconnects the underwater nodes through digital signal processing (DSP)-based modem by using acoustic links between the neighbouring sensors

Real-time implementations of acoustic signal enhancement techniques for aerial based surveillance and rescue applications

Science.gov (United States)

Ramos, Antonio L. L.; Shao, Zhili; Holthe, Aleksander; Sandli, Mathias F.

2017-05-01

The introduction of the System-on-Chip (SoC) technology has brought exciting new opportunities for the development of smart low cost embedded systems spanning a wide range of applications. Currently available SoC devices are capable of performing high speed digital signal processing tasks in software while featuring relatively low development costs and reduced time-to-market. Unmanned aerial vehicles (UAV) are an application example that has shown tremendous potential in an increasing number of scenarios, ranging from leisure to surveillance as well as in search and rescue missions. Video capturing from UAV platforms is a relatively straightforward task that requires almost no preprocessing. However, that does not apply to audio signals, especially in cases where the data is to be used to support real-time decision making. In fact, the enormous amount of acoustic interference from the surroundings, including the noise from the UAVs propellers, becomes a huge problem. This paper discusses a real-time implementation of the NLMS adaptive filtering algorithm applied to enhancing acoustic signals captured from UAV platforms. The model relies on a combination of acoustic sensors and a computational inexpensive algorithm running on a digital signal processor. Given its simplicity, this solution can be incorporated into the main processing system of an UAV using the SoC technology, and run concurrently with other required tasks, such as flight control and communications. Simulations and real-time DSP-based implementations have shown significant signal enhancement results by efficiently mitigating the interference from the noise generated by the UAVs propellers as well as from other external noise sources.

A Secure Communication Suite for Underwater Acoustic Sensor Networks

Directory of Open Access Journals (Sweden)

Angelica Lo Duca

2012-11-01

Full Text Available In this paper we describe a security suite for Underwater Acoustic Sensor Networks comprising both fixed and mobile nodes. The security suite is composed of a secure routing protocol and a set of cryptographic primitives aimed at protecting the confidentiality and the integrity of underwater communication while taking into account the unique characteristics and constraints of the acoustic channel. By means of experiments and simulations based on real data, we show that the suite is suitable for an underwater networking environment as it introduces limited, and sometimes negligible, communication and power consumption overhead.

Detection and Classification of Whale Acoustic Signals

Science.gov (United States)

Xian, Yin

This dissertation focuses on two vital challenges in relation to whale acoustic signals: detection and classification. In detection, we evaluated the influence of the uncertain ocean environment on the spectrogram-based detector, and derived the likelihood ratio of the proposed Short Time Fourier Transform detector. Experimental results showed that the proposed detector outperforms detectors based on the spectrogram. The proposed detector is more sensitive to environmental changes because it includes phase information. In classification, our focus is on finding a robust and sparse representation of whale vocalizations. Because whale vocalizations can be modeled as polynomial phase signals, we can represent the whale calls by their polynomial phase coefficients. In this dissertation, we used the Weyl transform to capture chirp rate information, and used a two dimensional feature set to represent whale vocalizations globally. Experimental results showed that our Weyl feature set outperforms chirplet coefficients and MFCC (Mel Frequency Cepstral Coefficients) when applied to our collected data. Since whale vocalizations can be represented by polynomial phase coefficients, it is plausible that the signals lie on a manifold parameterized by these coefficients. We also studied the intrinsic structure of high dimensional whale data by exploiting its geometry. Experimental results showed that nonlinear mappings such as Laplacian Eigenmap and ISOMAP outperform linear mappings such as PCA and MDS, suggesting that the whale acoustic data is nonlinear. We also explored deep learning algorithms on whale acoustic data. We built each layer as convolutions with either a PCA filter bank (PCANet) or a DCT filter bank (DCTNet). With the DCT filter bank, each layer has different a time-frequency scale representation, and from this, one can extract different physical information. Experimental results showed that our PCANet and DCTNet achieve high classification rate on the whale

Signal analysis of steam line acoustics

International Nuclear Information System (INIS)

Martin, C. Samuel

2003-01-01

The vibration of nuclear steam piping is usually associated with pressure fluctuations emanating from flow disturbances such as steam generator nozzles, bends, or other pipe fittings. Flow separation at pipe tees and within steam chest manifolds or headers generate pressure fluctuations that propagate both upstream to steam generators as well as downstream to the steam turbine. Steady-state acoustic oscillations at various frequencies occur within the piping, possibly exciting structural vibrations. This paper focuses on the assessment of the origin of the disturbances using signal analyses of two dynamic pressure recordings from pressure transducers located along straight runs in the steam piping. The technique involves performing the cross spectrum to two dynamic pressure signals in piping between (1) the steam generator and steam chest header, and (2) between the header and steam turbine outlet. If, at a specified frequency, no causality occurs between the two signals then the cross spectra magnitude will be negligible. Of interest here is the value of the phase between the two signals for frequencies for which the magnitude of the cross spectrum is not negligible. It is shown in the paper that the direction of the dominant waves at all frequencies can be related to the phase angle from the cross spectrum. It has to be realized that pressure waves emanating from one source such as a steam generator will propagate along uniform steam pipes with little transformation or attenuation, but will be reflected at fittings and at inlets and outlets. Hence, the eventual steady-state time record at a given location in the piping is a result of not only the disturbance, but also reflections of earlier pulsations. Cross-spectral analyses has been employed to determine the direction of the dominant acoustic waves in the piping for various frequencies for which there are signals. To prove the technique, synthetic spectra are generated comprised of harmonic waves moving both

Monitoring of drilling process with the application of acoustic signal

Directory of Open Access Journals (Sweden)

Labaš Milan

2000-09-01

Full Text Available Monitoring of rock disintegration process at drilling, scanning of input quantities: thrust F, revolution n and the course of some output quantities: the drilling rate v and the power input P are needed for the control of this process. We can calculate the specific volume work of rock disintegration w and ϕ - quotient of drilling rate v and the specific volume work of disintegration w from the presented quantities.Works on an expertimental stand showed that the correlation relationships between the input and output quantities can be found by scanning the accompanying sound of the drilling proces.Research of the rock disintegration with small-diameter diamond drill tools and different rock types is done at the Institute of Geotechnics. The aim of this research is the possibility of monitoring and controlling the rock disintegration process with the application of acoustic signal. The acoustic vibrations accompanying the drilling process are recorded by a microphone placed in a defined position in the acoustic space. The drilling device (drilling stand, the drilling tool and the rock are the source of sound. Two basic sound states exist in the drilling stand research : the noise at no-load running and the noise at the rotary drilling of rock. Suitable quantities for optimizing the rock disintegration process are searched by the study of the acoustic signal. The dominant frequencies that characterize the disintegration process for the given rock and tool are searched by the analysis of the acoustic signal. The analysis of dominant frequencies indicates the possibility of determining an optimal regime for the maximal drilling rate. Extreme of the specific disintegration energy is determinated by the dispersion of the dominant frequency.The scanned acoustic signal is processed by the Fourier transformation. The Fourier transformation facilitates the distribution of the general non-harmonic periodic process into harmonic components. The harmonic

Statistics of the acoustic emission signals parameters from Zircaloy-4 fuel cladding

International Nuclear Information System (INIS)

Oliveto, Maria E.; Lopez Pumarega, Maria I.; Ruzzante, Jose E.

2000-01-01

Statistic analysis of acoustic emission signals parameters: amplitude, duration and risetime was carried out. CANDU type Zircaloy-4 fuel claddings were pressurized up to rupture, one set of five normal pieces and six with defects included, acoustic emission was used on-line. Amplitude and duration frequency distributions were fitted with lognormal distribution functions, and risetime with an exponential one. Using analysis of variance, acoustic emission was appropriated to distinguish between defective and non-defective subsets. Clusters analysis applied on mean values of acoustic emission signal parameters were not effective to distinguish two sets of fuel claddings studied. (author)

Cicadas impact bird communication in a noisy tropical rainforest

Science.gov (United States)

Hall, Robert; Ray, William; Beck, Angela; Zook, James

2015-01-01

Many animals communicate through acoustic signaling, and “acoustic space” may be viewed as a limited resource that organisms compete for. If acoustic signals overlap, the information in them is masked, so there should be selection toward strategies that reduce signal overlap. The extent to which animals are able to partition acoustic space in acoustically diverse habitats such as tropical forests is poorly known. Here, we demonstrate that a single cicada species plays a major role in the frequency and timing of acoustic communication in a neotropical wet forest bird community. Using an automated acoustic monitor, we found that cicadas vary the timing of their signals throughout the day and that the frequency range and timing of bird vocalizations closely track these signals. Birds significantly avoid temporal overlap with cicadas by reducing and often shutting down vocalizations at the onset of cicada signals that utilize the same frequency range. When birds do vocalize at the same time as cicadas, the vocalizations primarily occur at nonoverlapping frequencies with cicada signals. Our results greatly improve our understanding of the community dynamics of acoustic signaling and reveal how patterns in biotic noise shape the frequency and timing of bird vocalizations in tropical forests. PMID:26023277

Design of acoustic logging signal source of imitation based on field programmable gate array

Science.gov (United States)

Zhang, K.; Ju, X. D.; Lu, J. Q.; Men, B. Y.

2014-08-01

An acoustic logging signal source of imitation is designed and realized, based on the Field Programmable Gate Array (FPGA), to improve the efficiency of examining and repairing acoustic logging tools during research and field application, and to inspect and verify acoustic receiving circuits and corresponding algorithms. The design of this signal source contains hardware design and software design,and the hardware design uses an FPGA as the control core. Four signals are made first by reading the Random Access Memory (RAM) data which are inside the FPGA, then dealing with the data by digital to analog conversion, amplification, smoothing and so on. Software design uses VHDL, a kind of hardware description language, to program the FPGA. Experiments illustrate that the ratio of signal to noise for the signal source is high, the waveforms are stable, and also its functions of amplitude adjustment, frequency adjustment and delay adjustment are in accord with the characteristics of real acoustic logging waveforms. These adjustments can be used to imitate influences on sonic logging received waveforms caused by many kinds of factors such as spacing and span of acoustic tools, sonic speeds of different layers and fluids, and acoustic attenuations of different cementation planes.

Coherent acoustic communication in a tidal estuary with busy shipping traffic

NARCIS (Netherlands)

Walree, P.A. van; Neasham, J.A.; Schrijver, M.C.

2007-01-01

High-rate acoustic communication experiments were conducted in a dynamic estuarine environment. Two current profilers deployed in a shipping lane were interfaced with acoustic modems, which modulated and transmitted the sensor readings every 200 s over a period of four days. QPSK modulation was

Signal analysis of acoustic and flow-induced vibrations of BWR main steam line

Energy Technology Data Exchange (ETDEWEB)

Espinosa-Paredes, G., E-mail: gepe@xanum.uam.mx [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Prieto-Guerrero, A. [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Núñez-Carrera, A. [Comisión Nacional de Seguridad Nuclear y Salvaguardias, Doctor Barragán 779, Col. Narvarte, México, D.F. 03020 (Mexico); Vázquez-Rodríguez, A. [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Centeno-Pérez, J. [Instituto Politécnico Nacional, Escuela Superior de Física y Matemáticas Unidad Profesional “Adolfo López Mateos”, Av. IPN, s/n, México, D.F. 07738 (Mexico); Espinosa-Martínez, E.-G. [Departamento de Sistemas Energéticos, Universidad Nacional Autónoma de México, México, D.F. 04510 (Mexico); and others

2016-05-15

Highlights: • Acoustic and flow-induced vibrations of BWR are analyzed. • BWR performance after extended power uprate is considered. • Effect of acoustic side branches (ASB) is analyzed. • The ASB represents a reduction in the acoustic loads to the steam dryer. • Methodology developed for simultaneous analyzing the signals in the MSL. - Abstract: The aim of this work is the signal analysis of acoustic waves due to phenomenon known as singing in Safety Relief Valves (SRV) of the main steam lines (MSL) in a typical BWR5. The acoustic resonance in SRV standpipes and fluctuating pressure is propagated from SRV to the dryer through the MSL. The signals are analyzed with a novel method based on the Multivariate Empirical Mode Decomposition (M-EMD). The M-EMD algorithm has the potential to find common oscillatory modes (IMF) within multivariate data. Based on this fact, we implement the M-EMD technique to find the oscillatory mode in BWR considering the measurements obtained collected by the strain gauges located around the MSL. These IMF, analyzed simultaneously in time, allow obtaining an estimation of the effects of the multiple-SRV in the MSL. Two scenarios are analyzed: the first is the signal obtained before the installation of the acoustic dampers (ASB), and the second, the signal obtained after installation. The results show the effectiveness of the ASB to damp the strong resonances when the steam flow increases, which represents an important reduction in the acoustic loads to the steam dryer.

Signal analysis of acoustic and flow-induced vibrations of BWR main steam line

International Nuclear Information System (INIS)

Espinosa-Paredes, G.; Prieto-Guerrero, A.; Núñez-Carrera, A.; Vázquez-Rodríguez, A.; Centeno-Pérez, J.; Espinosa-Martínez, E.-G.

2016-01-01

Highlights: • Acoustic and flow-induced vibrations of BWR are analyzed. • BWR performance after extended power uprate is considered. • Effect of acoustic side branches (ASB) is analyzed. • The ASB represents a reduction in the acoustic loads to the steam dryer. • Methodology developed for simultaneous analyzing the signals in the MSL. - Abstract: The aim of this work is the signal analysis of acoustic waves due to phenomenon known as singing in Safety Relief Valves (SRV) of the main steam lines (MSL) in a typical BWR5. The acoustic resonance in SRV standpipes and fluctuating pressure is propagated from SRV to the dryer through the MSL. The signals are analyzed with a novel method based on the Multivariate Empirical Mode Decomposition (M-EMD). The M-EMD algorithm has the potential to find common oscillatory modes (IMF) within multivariate data. Based on this fact, we implement the M-EMD technique to find the oscillatory mode in BWR considering the measurements obtained collected by the strain gauges located around the MSL. These IMF, analyzed simultaneously in time, allow obtaining an estimation of the effects of the multiple-SRV in the MSL. Two scenarios are analyzed: the first is the signal obtained before the installation of the acoustic dampers (ASB), and the second, the signal obtained after installation. The results show the effectiveness of the ASB to damp the strong resonances when the steam flow increases, which represents an important reduction in the acoustic loads to the steam dryer.

Study on acoustic emission signals of active defect in pressure piping under hydraulic pressure

International Nuclear Information System (INIS)

Ai Qiong; Liu Caixue; Wang Yao; He Pan; Song Jian

2009-01-01

Experimental investigations of acoustic emission (AE) of active defect in pressure piping with a prefabricated crack under hydraulic pressure tester were conducted. AE signals of fatigue-crack-growth in pressure piping were monitored incessantly in all processes, and all signals recorded were analyzed and processed. The result of signal processing show that the amplitude and energy of acoustic emission signals from defect in pressure pipeline increase gradually with the load time, and thus the active defects in pipeline can be identified; the amplitude, energy and count of acoustic emission signals increase sharply before the defect runs through, and we can forecast the penetrated leakage of pipeline. (authors)

Acoustic/seismic signal propagation and sensor performance modeling

Science.gov (United States)

Wilson, D. Keith; Marlin, David H.; Mackay, Sean

2007-04-01

Performance, optimal employment, and interpretation of data from acoustic and seismic sensors depend strongly and in complex ways on the environment in which they operate. Software tools for guiding non-expert users of acoustic and seismic sensors are therefore much needed. However, such tools require that many individual components be constructed and correctly connected together. These components include the source signature and directionality, representation of the atmospheric and terrain environment, calculation of the signal propagation, characterization of the sensor response, and mimicking of the data processing at the sensor. Selection of an appropriate signal propagation model is particularly important, as there are significant trade-offs between output fidelity and computation speed. Attenuation of signal energy, random fading, and (for array systems) variations in wavefront angle-of-arrival should all be considered. Characterization of the complex operational environment is often the weak link in sensor modeling: important issues for acoustic and seismic modeling activities include the temporal/spatial resolution of the atmospheric data, knowledge of the surface and subsurface terrain properties, and representation of ambient background noise and vibrations. Design of software tools that address these challenges is illustrated with two examples: a detailed target-to-sensor calculation application called the Sensor Performance Evaluator for Battlefield Environments (SPEBE) and a GIS-embedded approach called Battlefield Terrain Reasoning and Awareness (BTRA).

Real-time adaptive concepts in acoustics blind signal separation and multichannel echo cancellation

CERN Document Server

Schobben, Daniel W E

2001-01-01

Blind Signal Separation (BSS) deals with recovering (filtered versions of) source signals from an observed mixture thereof. The term `blind' relates to the fact that there are no reference signals for the source signals and also that the mixing system is unknown. This book presents a new method for blind signal separation, which is developed to work on microphone signals. Acoustic Echo Cancellation (AEC) is a well-known technique to suppress the echo that a microphone picks up from a loudspeaker in the same room. Such acoustic feedback occurs for example in hands-free telephony and can lead to a perceived loud tone. For an application such as a voice-controlled television, a stereo AEC is required to suppress the contribution of the stereo loudspeaker setup. A generalized AEC is presented that is suited for multi-channel operation. New algorithms for Blind Signal Separation and multi-channel Acoustic Echo Cancellation are presented. A background is given in array signal processing methods, adaptive filter the...

Design of acoustic logging signal source of imitation based on field programmable gate array

International Nuclear Information System (INIS)

Zhang, K; Ju, X D; Lu, J Q; Men, B Y

2014-01-01

An acoustic logging signal source of imitation is designed and realized, based on the Field Programmable Gate Array (FPGA), to improve the efficiency of examining and repairing acoustic logging tools during research and field application, and to inspect and verify acoustic receiving circuits and corresponding algorithms. The design of this signal source contains hardware design and software design,and the hardware design uses an FPGA as the control core. Four signals are made first by reading the Random Access Memory (RAM) data which are inside the FPGA, then dealing with the data by digital to analog conversion, amplification, smoothing and so on. Software design uses VHDL, a kind of hardware description language, to program the FPGA. Experiments illustrate that the ratio of signal to noise for the signal source is high, the waveforms are stable, and also its functions of amplitude adjustment, frequency adjustment and delay adjustment are in accord with the characteristics of real acoustic logging waveforms. These adjustments can be used to imitate influences on sonic logging received waveforms caused by many kinds of factors such as spacing and span of acoustic tools, sonic speeds of different layers and fluids, and acoustic attenuations of different cementation planes. (paper)

Low Bandwidth Vocoding using EM Sensor and Acoustic Signal Processing

International Nuclear Information System (INIS)

Ng, L C; Holzrichter, J F; Larson, P E

2001-01-01

Low-power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference [1]. By combining these data with the corresponding acoustic signal, we've demonstrated an almost 10-fold bandwidth reduction in speech compression, compared to a standard 2.4 kbps LPC10 protocol used in the STU-III (Secure Terminal Unit, third generation) telephone. This paper describes a potential EM sensor/acoustic based vocoder implementation

Holy grail: Pioneering acoustic telemetry technology set to revolutionize downhole communication

Energy Technology Data Exchange (ETDEWEB)

Greenaway, R.

2003-12-01

Acoustic telemetry, a faster and more efficient downhole-to-surface-communication technology, is the latest development in downhole communication systems. The system has been developed by Extreme Engineering Limited of Calgary, led by Derek Logan, founder and one-time senior vice-president of Ryan Energy Technologies that developed the original measurement -while-drilling (MWD) and logging-while-drilling )LWD) tools. The company predicts that acoustic telemetry will cause a massive transformation of the drilling industry in Western Canada once the technology is commercialized. Conventional MWD techniques, based on mud-pulse technology, have been industry standard since the 1970s, but mud-pulse technology is now considered extremely slow. In the 1980s industry came up electromagnetic telemetry, as an alternative to mud-pulse. Today, the need to transmit ever more data, the need for a faster communications system and greater wellbore control, has become even more pressing. Logan believes that acoustic technology is the answer. It is not only capable of transmitting data 20 to 30 times faster than mud-pulse telemetries, it can also communicate massive amounts of data. It can be used in drilling, completion production, drillstem testing, frac monitoring and any other wellbore process requiring wireless real-time telemetry. Acoustic telemetry is also the only wireless system that can perform MWD and LWD in offshore underbalanced drilling. Notwithstanding its great promise, Extreme Engineering Limited had considerable difficulty raising funds for developing and commercializing XAcT (the trade name for acoustic telemetry). Prospects are reported to have been substantially improved by recent infusion of funds by the federal Industrial Research Assistance Program (IRAP) , and XAcT's recognition by R and D Magazine with one of the R and D 100 awards for 2003. 3 figs.

Education in acoustics in Argentina

Science.gov (United States)

Miyara, Federico

2002-11-01

Over the last decades, education in acoustics (EA) in Argentina has experienced ups and downs due to economic and political issues interfering with long term projects. Unlike other countries, like Chile, where EA has reached maturity in spite of the acoustical industry having shown little development, Argentina has several well-established manufacturers of acoustic materials and equipment but no specific career with a major in acoustics. At the university level, acoustics is taught as a complementary--often elective--course for careers such as architecture, communication engineering, or music. In spite of this there are several research centers with programs covering environmental and community noise, effects of noise on man, acoustic signal processing, musical acoustics and acoustic emission, and several national and international meetings are held each year in which results are communicated and discussed. Several books on a variety of topics such as sound system, architectural acoustics, and noise control have been published as well. Another chapter in EA is technical and vocational education, ranging between secondary and postsecondary levels, with technical training on sound system operation or design. Over the last years there have been several attempts to implement master degrees in acoustics or audio engineering, with little or no success.

Additional signals due to negative refraction in acoustic microscopy of anisotropic plates

International Nuclear Information System (INIS)

Kozlov, A.V.; Mozhaev, V.G.

2008-01-01

The additional V(z) oscillations and pulses are predicted in the case of positive defocusing (focus above the sample surface) in acoustic microscopy of anisotropic plates exhibiting negative refraction of acoustic rays. The relationship between these additional signals and separate points on the acoustic slowness surface of the plate material is elucidated

Additional signals due to negative refraction in acoustic microscopy of anisotropic plates

Energy Technology Data Exchange (ETDEWEB)

Kozlov, A.V. [Faculty of Physics, Moscow State University, Moscow, 119991 GSP-1 (Russian Federation)], E-mail: av_kozlov@inbox.ru; Mozhaev, V.G. [Faculty of Physics, Moscow State University, Moscow, 119991 GSP-1 (Russian Federation)], E-mail: vgmozhaev@mail.ru

2008-06-23

The additional V(z) oscillations and pulses are predicted in the case of positive defocusing (focus above the sample surface) in acoustic microscopy of anisotropic plates exhibiting negative refraction of acoustic rays. The relationship between these additional signals and separate points on the acoustic slowness surface of the plate material is elucidated.

Simulation of an Underwater Acoustic Communication Channel Characterized by Wind-Generated Surface Waves and Bubbles

NARCIS (Netherlands)

Dol, H.S.; Colin, M.E.G.D.; Ainslie, M.A.; Walree, P.A. van; Janmaat, J.

2012-01-01

Sea surface scattering by wind-generated waves and bubbles is regarded to be the main non-platform related cause of the time variability of shallow acoustic communication channels. Simulations for predicting the quality of acoustic communication links in such channels thus require adequate modeling

The characteristics of acoustic emission signal under composite destruction on GFRP gas cylinder

International Nuclear Information System (INIS)

Jee, Hyun Sup; Lee, Jong O; Ju, No Hoe; So, Cheal Ho; Lee, Jong Kyu

2013-01-01

This study is investigation of the characteristics for acoustic emission signal generated by destruction on glass fiber bundles and specimen that was machined composite materials surrounding the outside of GFRP cylinder. The Amplitude of acoustic emission signal gets bigger as the cutting angle of knife increases. Accordingly, the number of hits in destruction of composite materials specimen have more in longitudinal direction (longitudinal direction to the glass fiber) than in hoop direction (horizontal direction to the glass fiber) while the amplitude of signals were bigger in hoop direction than longitudinal direction. It was found out that the amplitude of the glass fiber breakage is more than 40 dB and that the amplitude of signal for matrix crack was less than 40 dB because matrix crack signal was not observed when threshold value is 40 dB and matrix crack signal suddenly appeared when threshold value is 32 dB. The slope of the amplitude is related to the acoustic emission source and the slope of the amplitude of the horizontal and vertical directions are 0.16 and 0.08. In particular, The slope of the amplitude of longitudinal direction breakage appear similar to the glass fiber breakage and therefore Acoustic emission source of longitudinal direction breakage is estimated the glass fiber breakage.

Leak detection in gas pipeline by acoustic and signal processing - A review

Science.gov (United States)

Adnan, N. F.; Ghazali, M. F.; Amin, M. M.; Hamat, A. M. A.

2015-12-01

The pipeline system is the most important part in media transport in order to deliver fluid to another station. The weak maintenance and poor safety will contribute to financial losses in term of fluid waste and environmental impacts. There are many classifications of techniques to make it easier to show their specific method and application. This paper's discussion about gas leak detection in pipeline system using acoustic method will be presented in this paper. The wave propagation in the pipeline is a key parameter in acoustic method when the leak occurs and the pressure balance of the pipe will generated by the friction between wall in the pipe. The signal processing is used to decompose the raw signal and show in time- frequency. Findings based on the acoustic method can be used for comparative study in the future. Acoustic signal and HHT is the best method to detect leak in gas pipelines. More experiments and simulation need to be carried out to get the fast result of leaking and estimation of their location.

Impact of the Test Device on the Behavior of the Acoustic Emission Signals: Contribution of the Numerical Modeling to Signal Processing

Science.gov (United States)

Issiaka Traore, Oumar; Cristini, Paul; Favretto-Cristini, Nathalie; Pantera, Laurent; Viguier-Pla, Sylvie

2018-01-01

In a context of nuclear safety experiment monitoring with the non destructive testing method of acoustic emission, we study the impact of the test device on the interpretation of the recorded physical signals by using spectral finite element modeling. The numerical results are validated by comparison with real acoustic emission data obtained from previous experiments. The results show that several parameters can have significant impacts on acoustic wave propagation and then on the interpretation of the physical signals. The potential position of the source mechanism, the positions of the receivers and the nature of the coolant fluid have to be taken into account in the definition a pre-processing strategy of the real acoustic emission signals. In order to show the relevance of such an approach, we use the results to propose an optimization of the positions of the acoustic emission sensors in order to reduce the estimation bias of the time-delay and then improve the localization of the source mechanisms.

Analysis of acoustic sound signal for ONB measurement

International Nuclear Information System (INIS)

Park, S. J.; Kim, H. I.; Han, K. Y.; Chai, H. T.; Park, C.

2003-01-01

The onset of nucleate boiling (ONB) was measured in a test fuel bundle composed of several fuel element simulators (FES) by analysing the aquatic sound signals. In order measure ONBs, a hydrophone, a pre-amplifier, and a data acquisition system to acquire/process the aquatic signal was prepared. The acoustic signal generated in the coolant is converted to the current signal through the microphone. When the signal is analyzed in the frequency domain, each sound signal can be identified according to its origin of sound source. As the power is increased to a certain degree, a nucleate boiling is started. The frequent formation and collapse of the void bubbles produce sound signal. By measuring this sound signal one can pinpoint the ONB. Since the signal characteristics is identical for different mass flow rates, this method can be applicable for ascertaining ONB

Amplitude calibration of an acoustic backscattered signal from a bottom-moored ADCP based on long-term measurement series

Science.gov (United States)

Piotukh, V. B.; Zatsepin, A. G.; Kuklev, S. B.

2017-05-01

A possible approach to, and preliminary results of, amplitude calibration of acoustic signals backscattered from an ADCP moored at the bottom of the near-shelf zone of the Black Sea is considered. The aim of this work is to obtain vertical profiles of acoustic scattering signal levels, showing the real characteristics of the volume content of suspended sediments in sea water in units of conventional acoustic turbidity for a given signal frequency. In this case, the assumption about the intervals of maximum acoustic transparency and vertical homogeneity of the marine environment in long-term series of ADCP measurements is used. According to this hypothesis, the intervals of the least values of acoustic backscattered signals are detected, an empirical transfer function of the ADCP reception path is constructed, and it is calibrated. Normalized sets of acoustic backscattered signals relative to a signal from a level of conventionally clear water are obtained. New features in the behavior of vertical profiles of an acoustic echo-signal are revealed due to the calibration. The results of this work will be used in subsequent analysis of the vertical and time variations in suspended sediment content in the near-shelf zone of the Black Sea.

Mesoscale variations in acoustic signals induced by atmospheric gravity waves.

Science.gov (United States)

Chunchuzov, Igor; Kulichkov, Sergey; Perepelkin, Vitaly; Ziemann, Astrid; Arnold, Klaus; Kniffka, Anke

2009-02-01

The results of acoustic tomographic monitoring of the coherent structures in the lower atmosphere and the effects of these structures on acoustic signal parameters are analyzed in the present study. From the measurements of acoustic travel time fluctuations (periods 1 min-1 h) with distant receivers, the temporal fluctuations of the effective sound speed and wind speed are retrieved along different ray paths connecting an acoustic pulse source and several receivers. By using a coherence analysis of the fluctuations near spatially distanced ray turning points, the internal wave-associated fluctuations are filtered and their spatial characteristics (coherences, horizontal phase velocities, and spatial scales) are estimated. The capability of acoustic tomography in estimating wind shear near ground is shown. A possible mechanism describing the temporal modulation of the near-ground wind field by ducted internal waves in the troposphere is proposed.

Acoustical communications by means of small explosive charges

International Nuclear Information System (INIS)

Edrington, T.S.

1984-03-01

An acoustical communication system that conveys information by modulating the time intervals between detonations of small (subgram) explosive charges has been designed and field-tested. In addition to an information capacity of about 20 bits per charge, the system provides a means for making inferences about sound speed and attenuation in the propagation medium

The Relationship Between Acoustic Signal Typing and Perceptual Evaluation of Tracheoesophageal Voice Quality for Sustained Vowels.

Science.gov (United States)

Clapham, Renee P; van As-Brooks, Corina J; van Son, Rob J J H; Hilgers, Frans J M; van den Brekel, Michiel W M

2015-07-01

To investigate the relationship between acoustic signal typing and perceptual evaluation of sustained vowels produced by tracheoesophageal (TE) speakers and the use of signal typing in the clinical setting. Two evaluators independently categorized 1.75-second segments of narrow-band spectrograms according to acoustic signal typing and independently evaluated the recording of the same segments on a visual analog scale according to overall perceptual acoustic voice quality. The relationship between acoustic signal typing and overall voice quality (as a continuous scale and as a four-point ordinal scale) was investigated and the proportion of inter-rater agreement as well as the reliability between the two measures is reported. The agreement between signal type (I-IV) and ordinal voice quality (four-point scale) was low but significant, and there was a significant linear relationship between the variables. Signal type correctly predicted less than half of the voice quality data. There was a significant main effect of signal type on continuous voice quality scores with significant differences in median quality scores between signal types I-IV, I-III, and I-II. Signal typing can be used as an adjunct to perceptual and acoustic evaluation of the same stimuli for TE speech as part of a multidimensional evaluation protocol. Signal typing in its current form provides limited predictive information on voice quality, and there is significant overlap between signal types II and III and perceptual categories. Future work should consider whether the current four signal types could be refined. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

TH-CD-201-06: Experimental Characterization of Acoustic Signals Generated in Water Following Clinical Photon and Electron Beam Irradiation

International Nuclear Information System (INIS)

Hickling, S; El Naqa, I

2016-01-01

Purpose: Previous work has demonstrated the detectability of acoustic waves induced following the irradiation of high density metals with radiotherapy linac photon beams. This work demonstrates the ability to experimentally detect such acoustic signals following both photon and electron irradiation in a more radiotherapy relevant material. The relationship between induced acoustic signal properties in water and the deposited dose distribution is explored, and the feasibility of exploiting such signals for radiotherapy dosimetry is demonstrated. Methods: Acoustic waves were experimentally induced in a water tank via the thermoacoustic effect following a single pulse of photon or electron irradiation produced by a clinical linac. An immersion ultrasound transducer was used to detect these acoustic waves in water and signals were read out on an oscilloscope. Results: Peaks and troughs in the detected acoustic signals were found to correspond to the location of gradients in the deposited dose distribution following both photon and electron irradiation. Signal amplitude was linearly related to the dose per pulse deposited by photon or electron beams at the depth of detection. Flattening filter free beams induced large acoustic signals, and signal amplitude decreased with depth after the depth of maximum dose. Varying the field size resulted in a temporal shift of the acoustic signal peaks and a change in the detected signal frequency. Conclusion: Acoustic waves can be detected in a water tank following irradiation by linac photon and electron beams with basic electronics, and have characteristics related to the deposited dose distribution. The physical location of dose gradients and the amount of dose deposited can be inferred from the location and magnitude of acoustic signal peaks. Thus, the detection of induced acoustic waves could be applied to photon and electron water tank and in vivo dosimetry. This work was supported in part by CIHR grants MOP-114910 and MOP

Multireceiver Acoustic Communications in Time-Varying Environments

Science.gov (United States)

2014-06-01

Conf. on Computer Science and Information Technology (ICCSIT), Chengdu, China , 2010, pp. 606–609, vol. 9. [8] P. Bouvet and A. Loussert, “Capacity...analysis of underwater acoustic MIMO communications,”OCEANS, Sydney, NSW, 2010, pp. 1–8. [9] Wines lab (2013). Wireless networks and embedded... China , 2012, pp. 2059–2063. [17] S. Katwal, R. Nath and G. Murmu, “A simple Kalman channel equalizer using adaptive algorithms for time-variant channel

Brain Activation Patterns in Response to Conspecific and Heterospecific Social Acoustic Signals in Female Plainfin Midshipman Fish, Porichthys notatus.

Science.gov (United States)

Mohr, Robert A; Chang, Yiran; Bhandiwad, Ashwin A; Forlano, Paul M; Sisneros, Joseph A

2018-01-01

While the peripheral auditory system of fish has been well studied, less is known about how the fish's brain and central auditory system process complex social acoustic signals. The plainfin midshipman fish, Porichthys notatus, has become a good species for investigating the neural basis of acoustic communication because the production and reception of acoustic signals is paramount for this species' reproductive success. Nesting males produce long-duration advertisement calls that females detect and localize among the noise in the intertidal zone to successfully find mates and spawn. How female midshipman are able to discriminate male advertisement calls from environmental noise and other acoustic stimuli is unknown. Using the immediate early gene product cFos as a marker for neural activity, we quantified neural activation of the ascending auditory pathway in female midshipman exposed to conspecific advertisement calls, heterospecific white seabass calls, or ambient environment noise. We hypothesized that auditory hindbrain nuclei would be activated by general acoustic stimuli (ambient noise and other biotic acoustic stimuli) whereas auditory neurons in the midbrain and forebrain would be selectively activated by conspecific advertisement calls. We show that neural activation in two regions of the auditory hindbrain, i.e., the rostral intermediate division of the descending octaval nucleus and the ventral division of the secondary octaval nucleus, did not differ via cFos immunoreactive (cFos-ir) activity when exposed to different acoustic stimuli. In contrast, female midshipman exposed to conspecific advertisement calls showed greater cFos-ir in the nucleus centralis of the midbrain torus semicircularis compared to fish exposed only to ambient noise. No difference in cFos-ir was observed in the torus semicircularis of animals exposed to conspecific versus heterospecific calls. However, cFos-ir was greater in two forebrain structures that receive auditory input, i

Acoustic Green's function extraction in the ocean

Science.gov (United States)

Zang, Xiaoqin

The acoustic Green's function (GF) is the key to understanding the acoustic properties of ocean environments. With knowledge of the acoustic GF, the physics of sound propagation, such as dispersion, can be analyzed; underwater communication over thousands of miles can be understood; physical properties of the ocean, including ocean temperature, ocean current speed, as well as seafloor bathymetry, can be investigated. Experimental methods of acoustic GF extraction can be categorized as active methods and passive methods. Active methods are based on employment of man-made sound sources. These active methods require less computational complexity and time, but may cause harm to marine mammals. Passive methods cost much less and do not harm marine mammals, but require more theoretical and computational work. Both methods have advantages and disadvantages that should be carefully tailored to fit the need of each specific environment and application. In this dissertation, we study one passive method, the noise interferometry method, and one active method, the inverse filter processing method, to achieve acoustic GF extraction in the ocean. The passive method of noise interferometry makes use of ambient noise to extract an approximation to the acoustic GF. In an environment with a diffusive distribution of sound sources, sound waves that pass through two hydrophones at two locations carry the information of the acoustic GF between these two locations; by listening to the long-term ambient noise signals and cross-correlating the noise data recorded at two locations, the acoustic GF emerges from the noise cross-correlation function (NCF); a coherent stack of many realizations of NCFs yields a good approximation to the acoustic GF between these two locations, with all the deterministic structures clearly exhibited in the waveform. To test the performance of noise interferometry in different types of ocean environments, two field experiments were performed and ambient noise

Gotta Go, Mom’s Calling: Dolphin (Tursiops truncatus Mothers Use Individually Distinctive Acoustic Signals To Call Their Calves

Directory of Open Access Journals (Sweden)

Stan A. Kuczaj II

2015-02-01

Full Text Available Dolphin calves often wander away from their mothers, which can compromise their safety and survival. Mothers can retrieve their calves by actively pursuing them or by signaling their wandering calves to return. However, little is known about the retrieval techniques employed by mothers in specific calf recall contexts. We experimentally investigated maternal calf retrieval methods by assessing behavioral and acoustic strategies employed by three Atlantic bottlenose dolphin mothers to elicit their calf’s return in a controlled, non-threatening setting. Three mothers were asked to retrieve their calves on cue in this setting, and could do so however they chose. Mothers were much more likely to use energetically less costly acoustic signals than physical retrievals. Each mother produced individually distinctive calls that incorporated the mother’s signature whistle but often also involved additional whistles and clicks. The dolphin mothers’ use of individually distinctive calls to request a calf’s return is consistent with the notion that other dolphins can distinguish such calls and provides additional support for the notion that dolphin communication is flexible rather than fixed.

Classification Identification of Acoustic Emission Signals from Underground Metal Mine Rock by ICIMF Classifier

Directory of Open Access Journals (Sweden)

Hongyan Zuo

2014-01-01

Full Text Available To overcome the drawback that fuzzy classifier was sensitive to noises and outliers, Mamdani fuzzy classifier based on improved chaos immune algorithm was developed, in which bilateral Gaussian membership function parameters were set as constraint conditions and the indexes of fuzzy classification effectiveness and number of correct samples of fuzzy classification as the subgoal of fitness function. Moreover, Iris database was used for simulation experiment, classification, and recognition of acoustic emission signals and interference signals from stope wall rock of underground metal mines. The results showed that Mamdani fuzzy classifier based on improved chaos immune algorithm could effectively improve the prediction accuracy of classification of data sets with noises and outliers and the classification accuracy of acoustic emission signal and interference signal from stope wall rock of underground metal mines was 90.00%. It was obvious that the improved chaos immune Mamdani fuzzy (ICIMF classifier was useful for accurate diagnosis of acoustic emission signal and interference signal from stope wall rock of underground metal mines.

Visual and acoustic signaling in three species of Brazilian nocturnal tree frogs (Anura, Hylidae

Directory of Open Access Journals (Sweden)

Luís Felipe Toledo

2007-06-01

Full Text Available Visual communication seems to be widespread among nocturnal anurans, however, reports of these behaviors in many Neotropical species are lacking. Therefore, we gathered information collected during several sporadic field expeditions in central and southern Brazil with three nocturnal tree frogs: Aplastodiscus perviridis, Hypsiboas albopunctatus and H. bischoffi. These species displayed various aggressive behaviors, both visual and acoustic, towards other males. For A. perviridis we described arm lifting and leg kicking; for H. albopunctatus we described the advertisement and territorial calls, visual signalizations, including a previously unreported behavior (short leg kicking, and male-male combat; and for H. bischoffiwe described the advertisement and fighting calls, toes and fingers trembling, leg lifting, and leg kicking. We speculate about the evolution of some behaviors and concluded that the use of visual signals among Neotropical anurans may be much more common than suggested by the current knowledge.

Acoustic fine structure may encode biologically relevant information for zebra finches.

Science.gov (United States)

Prior, Nora H; Smith, Edward; Lawson, Shelby; Ball, Gregory F; Dooling, Robert J

2018-04-18

The ability to discriminate changes in the fine structure of complex sounds is well developed in birds. However, the precise limit of this discrimination ability and how it is used in the context of natural communication remains unclear. Here we describe natural variability in acoustic fine structure of male and female zebra finch calls. Results from psychoacoustic experiments demonstrate that zebra finches are able to discriminate extremely small differences in fine structure, which are on the order of the variation in acoustic fine structure that is present in their vocal signals. Results from signal analysis methods also suggest that acoustic fine structure may carry information that distinguishes between biologically relevant categories including sex, call type and individual identity. Combined, our results are consistent with the hypothesis that zebra finches can encode biologically relevant information within the fine structure of their calls. This study provides a foundation for our understanding of how acoustic fine structure may be involved in animal communication.

Chaotic signals in digital communications

CERN Document Server

Eisencraft, Marcio; Suyama, Ricardo

2013-01-01

Chaotic Signals in Digital Communications combines fundamental background knowledge with state-of-the-art methods for using chaotic signals and systems in digital communications. The book builds a bridge between theoretical works and practical implementation to help researchers attain consistent performance in realistic environments. It shows the possible shortcomings of the chaos-based communication systems proposed in the literature, particularly when they are subjected to non-ideal conditions. It also presents a toolbox of techniques for researchers working to actually implement such system

The acoustic features of human laughter

Science.gov (United States)

Bachorowski, Jo-Anne; Owren, Michael J.

2002-05-01

Remarkably little is known about the acoustic features of laughter, despite laughter's ubiquitous role in human vocal communication. Outcomes are described for 1024 naturally produced laugh bouts recorded from 97 young adults. Acoustic analysis focused on temporal characteristics, production modes, source- and filter-related effects, and indexical cues to laugher sex and individual identity. The results indicate that laughter is a remarkably complex vocal signal, with evident diversity in both production modes and fundamental frequency characteristics. Also of interest was finding a consistent lack of articulation effects in supralaryngeal filtering. Outcomes are compared to previously advanced hypotheses and conjectures about this species-typical vocal signal.

Materials for Damping Ambient Acoustic and Vibration Signals, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Long-term exposure to even relatively low levels of acoustic and vibration signals has been shown to be potentially harmful to humans. A new class of piezoelectric...

Multiuser chirp modulation for underwater acoustic channel based on VTRM

Directory of Open Access Journals (Sweden)

Fei Yuan

2017-05-01

Full Text Available In this paper, an ascheme is proposed for multiuser underwater acoustic communication by using the multi-chirp rate signals. It differs from the well known TDMA (Time Division Multiple Access, FDMA (Frequency Division Multiple Access or CDMA (Code Division Multiple Access, by assigning each users with different chirp-rate carriers instead of the time, frequency or PN code. Multi-chirp rate signals can be separated from each other by FrFT (Fractional Fourier Transform, which can be regarded as the chirp-based decomposing, and superior to the match filter in the underwater acoustic channel. VTRM (Virtual Time Reverse Mirror is applied into the system to alleviate the ISI caused by the multipatch and make the equalization more simple. Results of computer simulations and pool experiments prove that the proposed multiuser underwater acoustic communication based on the multi-chirp rate exhibit well performance. Outfield experments carrie out in Xiamen Port show that using about 10 kHz bandwidth, four users could communicate at the same time with 425 bps with low BER and can match the UAC application.

Acoustic signal emission monitoring as a novel method to predict steam pops during radiofrequency ablation: preliminary observations.

Science.gov (United States)

Chik, William W B; Kosobrodov, Roman; Bhaskaran, Abhishek; Barry, Michael Anthony Tony; Nguyen, Doan Trang; Pouliopoulos, Jim; Byth, Karen; Sivagangabalan, Gopal; Thomas, Stuart P; Ross, David L; McEwan, Alistair; Kovoor, Pramesh; Thiagalingam, Aravinda

2015-04-01

Steam pop is an explosive rupture of cardiac tissue caused by tissue overheating above 100 °C, resulting in steam formation, predisposing to serious complications associated with radiofrequency (RF) ablations. However, there are currently no reliable techniques to predict the occurrence of steam pops. We propose the utility of acoustic signals emitted during RF ablation as a novel method to predict steam pop formation and potentially prevent serious complications. Radiofrequency generator parameters (power, impedance, and temperature) were temporally recorded during ablations performed in an in vitro bovine myocardial model. The acoustic system consisted of HTI-96-min hydrophone, microphone preamplifier, and sound card connected to a laptop computer. The hydrophone has the frequency range of 2 Hz to 30 kHz and nominal sensitivity in the range -240 to -165 dB. The sound was sampled at 96 kHz with 24-bit resolution. Output signal from the hydrophone was fed into the camera audio input to synchronize the video stream. An automated system was developed for the detection and analysis of acoustic events. Nine steam pops were observed. Three distinct sounds were identified as warning signals, each indicating rapid steam formation and its release from tissue. These sounds had a broad frequency range up to 6 kHz with several spectral peaks around 2-3 kHz. Subjectively, these warning signals were perceived as separate loud clicks, a quick succession of clicks, or continuous squeaking noise. Characteristic acoustic signals were identified preceding 80% of pops occurrence. Six cardiologists were able to identify 65% of acoustic signals accurately preceding the pop. An automated system identified the characteristic warning signals in 85% of cases. The mean time from the first acoustic signal to pop occurrence was 46 ± 20 seconds. The automated system had 72.7% sensitivity and 88.9% specificity for predicting pops. Easily identifiable characteristic acoustic emissions

Communication Signals in Lizards.

Science.gov (United States)

Carpenter, Charles C.

1983-01-01

Discusses mechanisms and functional intent of visual communication signals in iguanid/agamid lizards. Demonstrated that lizards communicate with each other by using pushups and head nods and that each species does this in its own way, conveying different types of information. (JN)

Surface Wave Focusing and Acoustic Communications in the Surf Zone

National Research Council Canada - National Science Library

Preisig, James

2004-01-01

The forward scattering of acoustic signals off of shoaling surface gravity waves in the surf zone results in a time-varying channel impulse response that is characterized by intense, rapidly fluctuating arrivals...

Quantifying loss of acoustic communication space for right whales in and around a U.S. National Marine Sanctuary.

Science.gov (United States)

Hatch, Leila T; Clark, Christopher W; Van Parijs, Sofie M; Frankel, Adam S; Ponirakis, Dimitri W

2012-12-01

The effects of chronic exposure to increasing levels of human-induced underwater noise on marine animal populations reliant on sound for communication are poorly understood. We sought to further develop methods of quantifying the effects of communication masking associated with human-induced sound on contact-calling North Atlantic right whales (Eubalaena glacialis) in an ecologically relevant area (~10,000 km(2) ) and time period (peak feeding time). We used an array of temporary, bottom-mounted, autonomous acoustic recorders in the Stellwagen Bank National Marine Sanctuary to monitor ambient noise levels, measure levels of sound associated with vessels, and detect and locate calling whales. We related wind speed, as recorded by regional oceanographic buoys, to ambient noise levels. We used vessel-tracking data from the Automatic Identification System to quantify acoustic signatures of large commercial vessels. On the basis of these integrated sound fields, median signal excess (the difference between the signal-to-noise ratio and the assumed recognition differential) for contact-calling right whales was negative (-1 dB) under current ambient noise levels and was further reduced (-2 dB) by the addition of noise from ships. Compared with potential communication space available under historically lower noise conditions, calling right whales may have lost, on average, 63-67% of their communication space. One or more of the 89 calling whales in the study area was exposed to noise levels ≥120 dB re 1 μPa by ships for 20% of the month, and a maximum of 11 whales were exposed to noise at or above this level during a single 10-min period. These results highlight the limitations of exposure-threshold (i.e., dose-response) metrics for assessing chronic anthropogenic noise effects on communication opportunities. Our methods can be used to integrate chronic and wide-ranging noise effects in emerging ocean-planning forums that seek to improve management of cumulative effects

Temperature and Pressure Dependence of Signal Amplitudes for Electrostriction Laser-Induced Thermal Acoustics

Science.gov (United States)

Herring, Gregory C.

2015-01-01

The relative signal strength of electrostriction-only (no thermal grating) laser-induced thermal acoustics (LITA) in gas-phase air is reported as a function of temperature T and pressure P. Measurements were made in the free stream of a variable Mach number supersonic wind tunnel, where T and P are varied simultaneously as Mach number is varied. Using optical heterodyning, the measured signal amplitude (related to the optical reflectivity of the acoustic grating) was averaged for each of 11 flow conditions and compared to the expected theoretical dependence of a pure-electrostriction LITA process, where the signal is proportional to the square root of [P*P /( T*T*T)].

Calcium signal communication in the central nervous system.

Science.gov (United States)

Braet, Katleen; Cabooter, Liesbet; Paemeleire, Koen; Leybaert, Luc

2004-02-01

The communication of calcium signals between cells is known to be operative between neurons where these signals integrate intimately with electrical and chemical signal communication at synapses. Recently, it has become clear that glial cells also exchange calcium signals between each other in cultures and in brain slices. This communication pathway has received utmost attention since it is known that astrocytic calcium signals can be induced by neuronal stimulation and can be communicated back to the neurons to modulate synaptic transmission. In addition to this, cells that are generally not considered as brain cells become progressively incorporated in the picture, as astrocytic calcium signals are reported to be communicated to endothelial cells of the vessel wall and can affect smooth muscle cell tone to influence the vessel diameter and thus blood flow. We review the available evidence for calcium signal communication in the central nervous system, taking into account a basic functional unit -the brain cell tripartite- consisting of neurons, glial cells and vascular cells and with emphasis on glial-vascular calcium signaling aspects.

Moisture estimation in power transformer oil using acoustic signals and spectral kurtosis

International Nuclear Information System (INIS)

Leite, Valéria C M N; Veloso, Giscard F C; Borges da Silva, Luiz Eduardo; Lambert-Torres, Germano; Borges da Silva, Jonas G; Pinto, João Onofre Pereira

2016-01-01

The aim of this paper is to present a new technique for estimating the contamination by moisture in power transformer insulating oil based on the spectral kurtosis analysis of the acoustic signals of partial discharges (PDs). Basically, in this approach, the spectral kurtosis of the PD acoustic signal is calculated and the correlation between its maximum value and the moisture percentage is explored to find a function that calculates the moisture percentage. The function can be easily implemented in DSP, FPGA, or any other type of embedded system for online moisture monitoring. To evaluate the proposed approach, an experiment is assembled with a piezoelectric sensor attached to a tank, which is filled with insulating oil samples contaminated by different levels of moisture. A device generating electrical discharges is submerged into the oil to simulate the occurrence of PDs. Detected acoustic signals are processed using fast kurtogram algorithm to extract spectral kurtosis values. The obtained data are used to find the fitting function that relates the water contamination to the maximum value of the spectral kurtosis. Experimental results show that the proposed method is suitable for online monitoring system of power transformers. (paper)

Investigation of signal models and methods for evaluating structures of processing telecommunication information exchange systems under acoustic noise conditions

Science.gov (United States)

Kropotov, Y. A.; Belov, A. A.; Proskuryakov, A. Y.; Kolpakov, A. A.

2018-05-01

The paper considers models and methods for estimating signals during the transmission of information messages in telecommunication systems of audio exchange. One-dimensional probability distribution functions that can be used to isolate useful signals, and acoustic noise interference are presented. An approach to the estimation of the correlation and spectral functions of the parameters of acoustic signals is proposed, based on the parametric representation of acoustic signals and the components of the noise components. The paper suggests an approach to improving the efficiency of interference cancellation and highlighting the necessary information when processing signals from telecommunications systems. In this case, the suppression of acoustic noise is based on the methods of adaptive filtering and adaptive compensation. The work also describes the models of echo signals and the structure of subscriber devices in operational command telecommunications systems.

Estimation of the Tool Condition by Applying the Wavelet Transform to Acoustic Emission Signals

International Nuclear Information System (INIS)

Gomez, M. P.; Piotrkowski, R.; Ruzzante, J. E.; D'Attellis, C. E.

2007-01-01

This work follows the search of parameters to evaluate the tool condition in machining processes. The selected sensing technique is acoustic emission and it is applied to a turning process of steel samples. The obtained signals are studied using the wavelet transformation. The tool wear level is quantified as a percentage of the final wear specified by the Standard ISO 3685. The amplitude and relevant scale obtained of acoustic emission signals could be related with the wear level

Signals structural analysis and processing: application to acoustic signals recorded during sodium boiling in a nuclear reactor

International Nuclear Information System (INIS)

Rodriguez, J.

1986-02-01

An acoustic system that uses examples to learn the structure of specific signals linked to a corresponding class of physical phenomena, and classify an unknown signal (possibly with noise present) into one of the learned classes is presented. The first stage consists of smoothing the data. The signal is represented as a trace according to background and event. To learn the structures in each class, smoothed, segmented signals are used. For classification, three operations to modify the signal so that it perfectly verifies the model description are available [fr

Enhanced acoustic sensing through wave compression and pressure amplification in anisotropic metamaterials.

Science.gov (United States)

Chen, Yongyao; Liu, Haijun; Reilly, Michael; Bae, Hyungdae; Yu, Miao

2014-10-15

Acoustic sensors play an important role in many areas, such as homeland security, navigation, communication, health care and industry. However, the fundamental pressure detection limit hinders the performance of current acoustic sensing technologies. Here, through analytical, numerical and experimental studies, we show that anisotropic acoustic metamaterials can be designed to have strong wave compression effect that renders direct amplification of pressure fields in metamaterials. This enables a sensing mechanism that can help overcome the detection limit of conventional acoustic sensing systems. We further demonstrate a metamaterial-enhanced acoustic sensing system that achieves more than 20 dB signal-to-noise enhancement (over an order of magnitude enhancement in detection limit). With this system, weak acoustic pulse signals overwhelmed by the noise are successfully recovered. This work opens up new vistas for the development of metamaterial-based acoustic sensors with improved performance and functionalities that are highly desirable for many applications.

Measurement of acoustic emission signal energy. Calibration and tests

International Nuclear Information System (INIS)

Chretien, N.; Bernard, P.; Fayolle, J.

1975-01-01

The possibility of using an Audimat W device for analyzing the electric energy of signals delivered by a piezo-electric sensor for acoustic emission was investigated. The characteristics of the prototype device could be improved. The tests performed revealed that the 7075-T651 aluminium alloy can be used as a reference material [fr

Beeping and piping: characterization of two mechano-acoustic signals used by honey bees in swarming

Science.gov (United States)

Schlegel, Thomas; Visscher, P. Kirk; Seeley, Thomas D.

2012-12-01

Of the many signals used by honey bees during the process of swarming, two of them—the stop signal and the worker piping signal—are not easily distinguished for both are mechano-acoustic signals produced by scout bees who press their bodies against other bees while vibrating their wing muscles. To clarify the acoustic differences between these two signals, we recorded both signals from the same swarm and at the same time, and compared them in terms of signal duration, fundamental frequency, and frequency modulation. Stop signals and worker piping signals differ in all three variables: duration, 174 ± 64 vs. 602 ± 377 ms; fundamental frequency, 407 vs. 451 Hz; and frequency modulation, absent vs. present. While it remains unclear which differences the bees use to distinguish the two signals, it is clear that they do so for the signals have opposite effects. Stop signals cause inhibition of actively dancing scout bees whereas piping signals cause excitation of quietly resting non-scout bees.

DCTNet and PCANet for acoustic signal feature extraction

OpenAIRE

Xian, Yin; Thompson, Andrew; Sun, Xiaobai; Nowacek, Douglas; Nolte, Loren

2016-01-01

We introduce the use of DCTNet, an efficient approximation and alternative to PCANet, for acoustic signal classification. In PCANet, the eigenfunctions of the local sample covariance matrix (PCA) are used as filterbanks for convolution and feature extraction. When the eigenfunctions are well approximated by the Discrete Cosine Transform (DCT) functions, each layer of of PCANet and DCTNet is essentially a time-frequency representation. We relate DCTNet to spectral feature representation method...

Wing, tail, and vocal contributions to the complex acoustic signals of courting Calliope hummingbirds

Directory of Open Access Journals (Sweden)

Christopher James CLARK

2011-04-01

Full Text Available Multi-component signals contain multiple signal parts expressed in the same physical modality. One way to identify individual components is if they are produced by different physical mechanisms. Here, I studied the mechanisms generating acoustic signals in the courtship displays of the Calliope hummingbird Stellula calliope. Display dives consisted of three synchronized sound elements, a high-frequency tone (hft, a low frequency tone (lft, and atonal sound pulses (asp, which were then followed by a frequency-modulated fall. Manipulating any of the rectrices (tail-feathers of wild males impaired production of the lft and asp but not the hft or fall, which are apparently vocal. I tested the sound production capabilities of the rectrices in a wind tunnel. Single rectrices could generate the lft but not the asp, whereas multiple rectrices tested together produced sounds similar to the asp when they fluttered and collided with their neighbors percussively, representing a previously unknown mechanism of sound production. During the shuttle display, a trill is generated by the wings during pulses in which the wingbeat frequency is elevated to 95 Hz, 40% higher than the typical hovering wingbeat frequency. The Calliope hummingbird courtship displays include sounds produced by three independent mechanisms, and thus include a minimum of three acoustic signal components. These acoustic mechanisms have different constraints and thus potentially contain different messages. Producing multiple acoustic signals via multiple mechanisms may be a way to escape the constraints present in any single mechanism [Current Zoology 57 (2: 187–196, 2011].

Near- Source, Seismo-Acoustic Signals Accompanying a NASCAR Race at the Texas Motor Speedway

Science.gov (United States)

Stump, B. W.; Hayward, C.; Underwood, R.; Howard, J. E.; MacPhail, M. D.; Golden, P.; Endress, A.

2014-12-01

Near-source, seismo-acoustic observations provide a unique opportunity to characterize urban sources, remotely sense human activities including vehicular traffic and monitor large engineering structures. Energy separately coupled into the solid earth and atmosphere provides constraints on not only the location of these sources but also the physics of the generating process. Conditions and distances at which these observations can be made are dependent upon not only local geological conditions but also atmospheric conditions at the time of the observations. In order to address this range of topics, an empirical, seismo-acoustic study was undertaken in and around the Texas Motor Speedway in the Dallas-Ft. Worth area during the first week of April 2014 at which time a range of activities associated with a series of NASCAR races occurred. Nine, seismic sensors were deployed around the 1.5-mile track for purposes of documenting the direct-coupled seismic energy from the passage of the cars and other vehicles on the track. Six infrasound sensors were deployed on a rooftop in a rectangular array configuration designed to provide high frequency beam forming for acoustic signals. Finally, a five-element infrasound array was deployed outside the track in order to characterize how the signals propagate away from the sources in the near-source region. Signals recovered from within the track were able to track and characterize the motion of a variety of vehicles during the race weekend including individual racecars. Seismic data sampled at 1000 sps documented strong Doppler effects as the cars approached and moved away from individual sensors. There were faint seismic signals that arrived at seismic velocity but local acoustic to seismic coupling as supported by the acoustic observations generated the majority of seismic signals. Actual seismic ground motions were small as demonstrated by the dominance of regional seismic signals from a magnitude 4.0 earthquake that arrived at

Acoustic system for communication in pipelines

Science.gov (United States)

Martin, II, Louis Peter; Cooper, John F [Oakland, CA

2008-09-09

A system for communication in a pipe, or pipeline, or network of pipes containing a fluid. The system includes an encoding and transmitting sub-system connected to the pipe, or pipeline, or network of pipes that transmits a signal in the frequency range of 3-100 kHz into the pipe, or pipeline, or network of pipes containing a fluid, and a receiver and processor sub-system connected to the pipe, or pipeline, or network of pipes containing a fluid that receives said signal and uses said signal for a desired application.

Developments in Acoustic Navigation and Communication for High-Latitude Ocean Research

Science.gov (United States)

Gobat, J.; Lee, C.

2006-12-01

Developments in autonomous platforms (profiling floats, drifters, long-range gliders and propeller-driven vehicles) offer the possibility of unprecedented access to logistically difficult polar regions that challenge conventional techniques. Currently, however, navigation and telemetry for these platforms rely on satellite positioning and communications poorly suited for high-latitude applications where ice cover restricts access to the sea surface. A similar infrastructure offering basin-wide acoustic geolocation and telemetry would allow the community to employ autonomous platforms to address previously intractable problems in Arctic oceanography. Two recent efforts toward the development of such an infrastructure are reported here. As part of an observational array monitoring fluxes through Davis Strait, development of real-time RAFOS acoustic navigation for gliders has been ongoing since autumn 2004. To date, test deployments have been conducted in a 260 Hz field in the Pacific and 780 Hz fields off Norway and in Davis Strait. Real-time navigation accuracy of ~1~km is achievable. Autonomously navigating gliders will operate under ice cover beginning in autumn 2006. In addition to glider navigation development, the Davis Strait array moorings carry fixed RAFOS recorders to study propagation over a range of distances under seasonally varying ice cover. Results from the under-ice propagation and glider navigation experiments are presented. Motivated by the need to coordinate these types of development efforts, an international group of acousticians, autonomous platform developers, high-latitude oceanographers and marine mammal researchers gathered in Seattle, U.S.A. from 27 February -- 1 March 2006 for an NSF Office of Polar Programs sponsored Acoustic Navigation and Communication for High-latitude Ocean Research (ANCHOR) workshop. Workshop participants focused on summarizing the current state of knowledge concerning Arctic acoustics, navigation and communications

Acoustic wave focusing in complex media using Nonlinear Time Reversal coded signal processing

Czech Academy of Sciences Publication Activity Database

Dos Santos, S.; Dvořáková, Zuzana; Lints, M.; Kůs, V.; Salupere, A.; Převorovský, Zdeněk

2014-01-01

Roč. 19, č. 12 (2014) ISSN 1435-4934. [European Conference on Non-Destructive Testing (ECNDT 2014) /11./. Praha, 06.10.2014-10.10.2014] Institutional support: RVO:61388998 Keywords : ultrasonic testing (UT) * signal processing * TR- NEWS * nonlinear time reversal * NDT * nonlinear acoustics Subject RIV: BI - Acoustics http://www.ndt.net/events/ECNDT2014/app/content/Slides/590_DosSantos_Rev1.pdf

The Acoustic Structure and Information Content of Female Koala Vocal Signals

Science.gov (United States)

Charlton, Benjamin D.

2015-01-01

Determining the information content of animal vocalisations can give valuable insights into the potential functions of vocal signals. The source-filter theory of vocal production allows researchers to examine the information content of mammal vocalisations by linking variation in acoustic features with variation in relevant physical characteristics of the caller. Here I used a source-filter theory approach to classify female koala vocalisations into different call-types, and determine which acoustic features have the potential to convey important information about the caller to other conspecifics. A two-step cluster analysis classified female calls into bellows, snarls and tonal rejection calls. Additional results revealed that female koala vocalisations differed in their potential to provide information about a given caller’s phenotype that may be of importance to receivers. Female snarls did not contain reliable acoustic cues to the caller’s identity and age. In contrast, female bellows and tonal rejection calls were individually distinctive, and the tonal rejection calls of older female koalas had consistently lower mean, minimum and maximum fundamental frequency. In addition, female bellows were significantly shorter in duration and had higher fundamental frequency, formant frequencies, and formant frequency spacing than male bellows. These results indicate that female koala vocalisations have the potential to signal the caller’s identity, age and sex. I go on to discuss the anatomical basis for these findings, and consider the possible functional relevance of signalling this type of information in the koala’s natural habitat. PMID:26465340

Acoustic-Seismic Coupling of Broadband Signals - Analysis of Potential Disturbances during CTBT On-Site Inspection Measurements

Science.gov (United States)

Liebsch, Mattes; Altmann, Jürgen

2015-04-01

For the verification of the Comprehensive Nuclear Test Ban Treaty (CTBT) the precise localisation of possible underground nuclear explosion sites is important. During an on-site inspection (OSI) sensitive seismic measurements of aftershocks can be performed, which, however, can be disturbed by other signals. To improve the quality and effectiveness of these measurements it is essential to understand those disturbances so that they can be reduced or prevented. In our work we focus on disturbing signals caused by airborne sources: When the sound of aircraft (as often used by the inspectors themselves) hits the ground, it propagates through pores in the soil. Its energy is transferred to the ground and soil vibrations are created which can mask weak aftershock signals. The understanding of the coupling of acoustic waves to the ground is still incomplete. However, it is necessary to improve the performance of an OSI, e.g. to address potential consequences for the sensor placement, the helicopter trajectories etc. We present our recent advances in this field. We performed several measurements to record sound pressure and soil velocity produced by various sources, e.g. broadband excitation by jet aircraft passing overhead and signals artificially produced by a speaker. For our experimental set-up microphones were placed close to the ground and geophones were buried in different depths in the soil. Several sensors were shielded from the directly incident acoustic signals by a box coated with acoustic damping material. While sound pressure under the box was strongly reduced, the soil velocity measured under the box was just slightly smaller than outside of it. Thus these soil vibrations were mostly created outside the box and travelled through the soil to the sensors. This information is used to estimate characteristic propagation lengths of the acoustically induced signals in the soil. In the seismic data we observed interference patterns which are likely caused by the

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization

Directory of Open Access Journals (Sweden)

Nasir Saeed

2017-12-01

Full Text Available Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB is derived for localization accuracy of the proposed technique.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization.

Science.gov (United States)

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y; Alouini, Mohamed-Slim

2017-12-26

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization

KAUST Repository

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2017-01-01

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization

KAUST Repository

Saeed, Nasir

2017-12-26

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique.

Deciphering acoustic emission signals in drought stressed branches: the missing link between source and sensor

Directory of Open Access Journals (Sweden)

Lidewei L Vergeynst

2015-07-01

Full Text Available When drought occurs in plants, acoustic emission signals can be detected, but the actual causes of these signals are still unknown. By analyzing the waveforms of the measured signals, it should however be possible to trace the characteristics of the acoustic emission source and get information about the underlying physiological processes. A problem encountered during this analysis is that the waveform changes significantly from source to sensor and lack of knowledge on wave propagation impedes research progress made in this field. We used finite element modeling and the well-known pencil lead break source to investigate wave propagation in a branch. A cylindrical rod of polyvinyl chloride was first used to identify the theoretical propagation modes. Two wave propagation modes could be distinguished and we used the finite element model to interpret their behavior in terms of source position for both the PVC rod and a wooden rod. Both wave propagation modes were also identified in drying-induced signals from woody branches, and we used the obtained insights to provide recommendations for further acoustic emission research in plant science.

Coupled Research in Ocean Acoustics and Signal Processing for the Next Generation of Underwater Acoustic Communication Systems

Science.gov (United States)

2016-08-05

the analysis of data collected during the VHF acoustics test con - ducted in a wave tank at the Scripps Institution of Oceanography in October 2015...a first look at the statistics, the Scintillation Index (traditional narrowband def - inition) was calculated as a function of arrival delay and wind

A Novel Fractional Fourier Transform-Based ASK-OFDM System for Underwater Acoustic Communications

Directory of Open Access Journals (Sweden)

Rami Ashri

2017-12-01

Full Text Available A key research area in wireless transmission is underwater communications. It has a vital role in applications such as underwater sensor networks (UWSNs and disaster detection. The underwater channel is very unique as compared to other alternatives of transmission channels. It is characterized by path loss, multipath fading, Doppler spread and ambient noise. Thus, the bit error rate (BER is increased to a large extent when compared to its counterpart of cellular communications. Acoustic signals are the current best solution for underwater communications. The use of electromagnetic or optical waves obviously entails a much higher data rate. However, they suffer from high attenuation, absorption or scattering. This paper proposes a novel fractional fast Fourier transform (FrFT—orthogonal frequency division multiplexing (FrFT-OFDM system for underwater acoustic (UWA communication—which employs the amplitude shift keying (ASK modulation technique (FrFT-ASK-OFDM. Specifically, ASK achieves a better bandwidth efficiency as compared to other commonly used modulation techniques, such as quadrature amplitude modulation (QAM and phase shift keying (PSK. In particular, the system proposed in this article can achieve a very promising BER performance, and can reach higher data rates when compared to other systems proposed in the literature. The BER performance of the proposed system is evaluated numerically, and is compared to the corresponding M-ary QAM system in the UWA channel for the same channel conditions. Moreover, the performance of the proposed system is compared to the conventional fast Fourier transform (FFT-OFDM (FFT-OFDM system in the absence and presence of the effect of carrier frequency offset (CFO. Numerical results show that the proposed system outperforms the conventional FFT-based systems for UWA channels, even in channels dominated by CFO. Moreover, the spectral efficiency and data rate of the proposed system are approximately double

Mobile Communication Devices, Ambient Noise, and Acoustic Voice Measures.

Science.gov (United States)

Maryn, Youri; Ysenbaert, Femke; Zarowski, Andrzej; Vanspauwen, Robby

2017-03-01

The ability to move with mobile communication devices (MCDs; ie, smartphones and tablet computers) may induce differences in microphone-to-mouth positioning and use in noise-packed environments, and thus influence reliability of acoustic voice measurements. This study investigated differences in various acoustic voice measures between six recording equipments in backgrounds with low and increasing noise levels. One chain of continuous speech and sustained vowel from 50 subjects with voice disorders (all separated by silence intervals) was radiated and re-recorded in an anechoic chamber with five MCDs and one high-quality recording system. These recordings were acquired in one condition without ambient noise and in four conditions with increased ambient noise. A total of 10 acoustic voice markers were obtained in the program Praat. Differences between MCDs and noise condition were assessed with Friedman repeated-measures test and posthoc Wilcoxon signed-rank tests, both for related samples, after Bonferroni correction. (1) Except median fundamental frequency and seven nonsignificant differences, MCD samples have significantly higher acoustic markers than clinical reference samples in minimal environmental noise. (2) Except median fundamental frequency, jitter local, and jitter rap, all acoustic measures on samples recorded with the reference system experienced significant influence from room noise levels. Fundamental frequency is resistant to recording system, environmental noise, and their combination. All other measures, however, were impacted by both recording system and noise condition, and especially by their combination, often already in the reference/baseline condition without added ambient noise. Caution is therefore warranted regarding implementation of MCDs as clinical recording tools, particularly when applied for treatment outcomes assessments. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Acoustic Signal Processing for Pipe Condition Assessment (WaterRF Report 4360)

Science.gov (United States)

Unique to prestressed concrete cylinder pipe (PCCP), individual wire breaks create an excitation in the pipe wall that may vary in response to the remaining compression of the pipe core. This project was designed to improve acoustic signal processing for pipe condition assessment...

How females of chirping and trilling field crickets integrate the 'what' and 'where' of male acoustic signals during decision making.

Science.gov (United States)

Gabel, Eileen; Gray, David A; Matthias Hennig, R

2016-11-01

In crickets acoustic communication serves mate selection. Female crickets have to perceive and integrate male cues relevant for mate choice while confronted with several different signals in an acoustically diverse background. Overall female decisions are based on the attractiveness of the temporal pattern (informative about the 'what') and on signal intensity (informative about the 'where') of male calling songs. Here, we investigated how the relevant cues for mate choice are integrated during the decision process by females of five different species of chirping and trilling field crickets. Using a behavioral design, female preferences in no-choice and choice situations for male calling songs differing in pulse rate, modulation depth, intensities, chirp/trill arrangements and temporal shifts were examined. Sensory processing underlying decisions in female field crickets is rather similar as combined evidence suggested that incoming song patterns were analyzed separately by bilaterally paired networks for pattern attractiveness and pattern intensity. A downstream gain control mechanism leads to a weighting of the intensity cue by pattern attractiveness. While remarkable differences between species were observed with respect to specific processing steps, closely related species exhibited more similar preferences than did more distantly related species.

Validation of simulations of an underwater acoustic communication channel characterized by wind-generated surface waves and bubbles

NARCIS (Netherlands)

Dol, H.S.; Colin, M.E.G.D.; Ainlie, M.A.; Gerdes, F.; Schäfke, A.; Özkan Sertlekc, H.

2013-01-01

This paper shows that it is possible to simulate realistic shallow-water acoustic communication channels using available acoustic propagation models. Key factor is the incorporation of realistic time-dependent sea surface conditions, including both waves and bubbles due to wind.

Adaptive hearing in the vocal plainfin midshipman fish: getting in tune for the breeding season and implications for acoustic communication.

Science.gov (United States)

Sisneros, Joseph A

2009-03-01

The plainfin midshipman fish (Porichthys notatus Girard, 1854) is a vocal species of batrachoidid fish that generates acoustic signals for intraspecific communication during social and reproductive activity and has become a good model for investigating the neural and endocrine mechanisms of vocal-acoustic communication. Reproductively active female plainfin midshipman fish use their auditory sense to detect and locate "singing" males, which produce a multiharmonic advertisement call to attract females for spawning. The seasonal onset of male advertisement calling in the midshipman fish coincides with an increase in the range of frequency sensitivity of the female's inner ear saccule, the main organ of hearing, thus leading to enhanced encoding of the dominant frequency components of male advertisement calls. Non-reproductive females treated with either testosterone or 17β-estradiol exhibit a dramatic increase in the inner ear's frequency sensitivity that mimics the reproductive female's auditory phenotype and leads to an increased detection of the male's advertisement call. This novel form of auditory plasticity provides an adaptable mechanism that enhances coupling between sender and receiver in vocal communication. This review focuses on recent evidence for seasonal reproductive-state and steroid-dependent plasticity of auditory frequency sensitivity in the peripheral auditory system of the midshipman fish. The potential steroid-dependent mechanism(s) that lead to this novel form of auditory and behavioral plasticity are also discussed. © 2009 ISZS, Blackwell Publishing and IOZ/CAS.

Sensor and transmitter system for communication in pipelines

Science.gov (United States)

Cooper, John F.; Burnham, Alan K.

2013-01-29

A system for sensing and communicating in a pipeline that contains a fluid. An acoustic signal containing information about a property of the fluid is produced in the pipeline. The signal is transmitted through the pipeline. The signal is received with the information and used by a control.

Automatic modulation recognition of communication signals

CERN Document Server

Azzouz, Elsayed Elsayed

1996-01-01

Automatic modulation recognition is a rapidly evolving area of signal analysis. In recent years, interest from the academic and military research institutes has focused around the research and development of modulation recognition algorithms. Any communication intelligence (COMINT) system comprises three main blocks: receiver front-end, modulation recogniser and output stage. Considerable work has been done in the area of receiver front-ends. The work at the output stage is concerned with information extraction, recording and exploitation and begins with signal demodulation, that requires accurate knowledge about the signal modulation type. There are, however, two main reasons for knowing the current modulation type of a signal; to preserve the signal information content and to decide upon the suitable counter action, such as jamming. Automatic Modulation Recognition of Communications Signals describes in depth this modulation recognition process. Drawing on several years of research, the authors provide a cr...

Low temperature tensile deformation and acoustic emission signal characteristics of AISI 304LN stainless steel

Energy Technology Data Exchange (ETDEWEB)

Barat, K.; Bar, H.N. [Material Science and Technology Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Mandal, D. [Material Processing and Technology Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Roy, H., E-mail: himadri9504@gmail.com [NDT and Metallurgy Group, CSIR-Central Mechanical Engineering Research Institute, Durgapur 713209 (India); Sivaprasad, S.; Tarafder, S. [Material Science and Technology Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India)

2014-03-01

This investigation examines low temperature tensile deformation behavior of AISI 304LN stainless steel along with synergistic analysis of acoustic emission signals. The tensile tests are done at a range of temperatures starting from 283 K till 223 K. The fracture surfaces of the broken specimens are investigated using scanning electron microscope. The amount of deformation induced martensite is measured using a feritscope. The obtained results reveal that with decrease in test temperature, both strength and ductility increase. The increase in strength and ductility with decreasing temperature is explained in terms of void morphologies and formation of deformation induced martensite. The rapid increment in strength and ductility at 223 K is associated with the burst of martensitic transformation at that temperature; which has been clarified from acoustic emission signals. An additional initiative has been taken to model the evolution of martensite formation from the observed cumulative emission counts using a non linear logarithmic functional form. The fitted curves from the recorded acoustic emission cumulative count data are found to be better correlated compared to earlier obtained results. However, at 223 K normal non-linear logarithmic fit is not found suitable due to presence of burst type signals at intervals, therefore; piecewise logarithmic function to model acoustic emission bursts is proposed.

Multimodal signalling in estrildid finches

DEFF Research Database (Denmark)

Gomes, A. C. R.; Funghi, C.; Soma, M.

2017-01-01

Sexual traits (e.g. visual ornaments, acoustic signals, courtship behaviour) are often displayed together as multimodal signals. Some hypotheses predict joint evolution of different sexual signals (e.g. to increase the efficiency of communication) or that different signals trade off with each other...... (e.g. due to limited resources). Alternatively, multiple signals may evolve independently for different functions, or to communicate different information (multiple message hypothesis). We evaluated these hypotheses with a comparative study in the family Estrildidae, one of the largest songbird...... compromise, but generally courtship dance also evolved independently from other signals. Instead of correlated evolution, we found that song, dance and colour are each related to different socio-ecological traits. Song complexity evolved together with ecological generalism, song performance with investment...

MIMO Underwater Acoustic Communications in Ports and Shallow Waters at Very High Frequency

Directory of Open Access Journals (Sweden)

Gaultier Real

2013-10-01

Full Text Available Hermes is a Single-Input Single-Output (SISO underwater acoustic modem that achieves very high-bit rate digital communications in ports and shallow waters. Here, the authors study the capability of Hermes to support Multiple-Input-Multiple-Output (MIMO technology. A least-square channel estimation algorithm is used to evaluate multiple MIMO channel impulse responses at the receiver end. A deconvolution routine is used to separate the messages coming from different sources. This paper covers the performance of both the channel estimation and the MIMO deconvolution processes using either simulated data or field data. The MIMO equalization performance is measured by comparing three relative root mean-squared errors (RMSE, obtained by calculations between the source signal (a pseudo-noise sequence and the corresponding received MIMO signal at various stages of the deconvolution process; prior to any interference removal, at the output of the Linear Equalization (LE process and at the output of an interference cancellation process with complete a priori knowledge of the transmitted signal. Using the simulated data, the RMSE using LE is −20.5 dB (where 0 dB corresponds to 100% of relative error while the lower bound value is −33.4 dB. Using experimental data, the LE performance is −3.3 dB and the lower bound RMSE value is −27 dB.

Concurrent signal combining and channel estimation in digital communications

Science.gov (United States)

Ormesher, Richard C [Albuquerque, NM; Mason, John J [Albuquerque, NM

2011-08-30

In the reception of digital information transmitted on a communication channel, a characteristic exhibited by the communication channel during transmission of the digital information is estimated based on a communication signal that represents the digital information and has been received via the communication channel. Concurrently with the estimating, the communication signal is used to decide what digital information was transmitted.

Dual fiber Bragg gratings configuration-based fiber acoustic sensor for low-frequency signal detection

Science.gov (United States)

Yang, Dong; Wang, Shun; Lu, Ping; Liu, Deming

2014-11-01

We propose and fabricate a new type fiber acoustic sensor based on dual fiber Bragg gratings (FBGs) configuration. The acoustic sensor head is constructed by putting the sensing cells enclosed in an aluminum cylinder space built by two Cband FBGs and a titanium diaphragm of 50 um thickness. One end of each FBG is longitudinally adhered to the diaphragm by UV glue. Both of the two FBGs are employed for reflecting light. The dual FBGs play roles not only as signal transmission system but also as sensing component, and they demodulate each other's optical signal mutually during the measurement. Both of the two FBGs are pre-strained and the output optical power experiences fluctuation in a linear relationship along with a variation of axial strain and surrounding acoustic interference. So a precise approach to measure the frequency and sound pressure of the acoustic disturbance is achieved. Experiments are performed and results show that a relatively flat frequency response in a range from 200 Hz to 1 kHz with the average signal-to-noise ratio (SNR) above 21 dB is obtained. The maximum sound pressure sensitivity of 11.35mV/Pa is achieved with the Rsquared value of 0.99131 when the sound pressure in the range of 87.7-106.6dB. It has potential applications in low frequency signal detection. Owing to its direct self-demodulation method, the sensing system reveals the advantages of easy to demodulate, good temperature stability and measurement reliability. Besides, performance of the proposed sensor could be improved by optimizing the parameters of the sensor, especially the diaphragm.

Gearbox fault diagnosis based on deep random forest fusion of acoustic and vibratory signals

Science.gov (United States)

Li, Chuan; Sanchez, René-Vinicio; Zurita, Grover; Cerrada, Mariela; Cabrera, Diego; Vásquez, Rafael E.

2016-08-01

Fault diagnosis is an effective tool to guarantee safe operations in gearboxes. Acoustic and vibratory measurements in such mechanical devices are all sensitive to the existence of faults. This work addresses the use of a deep random forest fusion (DRFF) technique to improve fault diagnosis performance for gearboxes by using measurements of an acoustic emission (AE) sensor and an accelerometer that are used for monitoring the gearbox condition simultaneously. The statistical parameters of the wavelet packet transform (WPT) are first produced from the AE signal and the vibratory signal, respectively. Two deep Boltzmann machines (DBMs) are then developed for deep representations of the WPT statistical parameters. A random forest is finally suggested to fuse the outputs of the two DBMs as the integrated DRFF model. The proposed DRFF technique is evaluated using gearbox fault diagnosis experiments under different operational conditions, and achieves 97.68% of the classification rate for 11 different condition patterns. Compared to other peer algorithms, the addressed method exhibits the best performance. The results indicate that the deep learning fusion of acoustic and vibratory signals may improve fault diagnosis capabilities for gearboxes.

Acoustic signalling in a small, socially monogamous canid

DEFF Research Database (Denmark)

Darden, Safi-Kirstine; Dabelsteen, Torben

2008-01-01

Animals that actively defend all or part of their home range for the exclusive use of members of their social group are considered territorial. Defended areas may contain resources such as dens or nests, key foraging sites, or sexual partners that vary in value by season. We investigated territor....... These results suggest that the barking sequence is used in territorial defence and we conclude that at least male swift foxes are territorial in the mating season and they use a long-ranging acoustic signal in territory defence....

Auto-identification of engine fault acoustic signal through inverse trigonometric instantaneous frequency analysis

Directory of Open Access Journals (Sweden)

Dayong Ning

2016-03-01

Full Text Available The acoustic signals of internal combustion engines contain valuable information about the condition of engines. These signals can be used to detect incipient faults in engines. However, these signals are complex and composed of a faulty component and other noise signals of background. As such, engine conditions’ characteristics are difficult to extract through wavelet transformation and acoustic emission techniques. In this study, an instantaneous frequency analysis method was proposed. A new time–frequency model was constructed using a fixed amplitude and a variable cycle sine function to fit adjacent points gradually from a time domain signal. The instantaneous frequency corresponds to single value at any time. This study also introduced instantaneous frequency calculation on the basis of an inverse trigonometric fitting method at any time. The mean value of all local maximum values was then considered to identify the engine condition automatically. Results revealed that the mean of local maximum values under faulty conditions differs from the normal mean. An experiment case was also conducted to illustrate the availability of the proposed method. Using the proposed time–frequency model, we can identify engine condition and determine abnormal sound produced by faulty engines.

Signals in Communication Engineering History

Science.gov (United States)

Consonni, Denise; Silva, Magno T. M.

2010-01-01

This paper is a study of various electric signals, which have been employed throughout the history of communication engineering in its two main landmarks: the telegraph and the telephone. The signals are presented in their time and frequency domain representations. The historical order has been followed in the presentation: wired systems, spark…

Combined Hybrid DFE and CCK Remodulator for Medium-Range Single-Carrier Underwater Acoustic Communications

Directory of Open Access Journals (Sweden)

Xialin Jiang

2017-01-01

Full Text Available Advanced modulation and channel equalization techniques are essential for improving the performance of medium-range single-carrier underwater acoustic communications. In this paper, an enhanced detection scheme, hybrid time-frequency domain decision feedback equalizer (DFE combined with complementary code keying (CCK remodulator, is presented. CCK modulation technique provides strong tolerance to intersymbol interference caused by multipath propagation in underwater acoustic channels. The conventional hybrid DFE, using a frequency domain feedforward filter and a time domain feedback filter, provides good performance along with low computational complexity. The error propagation in the feedback filter, caused by feedbacking wrong decisions prior to CCK demodulation, may lead to great performance degradation. In our proposed scheme, with the help of CCK coding gain, more accurate remodulated CCK chips can be used as feedback. The proposed detection scheme is tested by the practical ocean experiments. The experimental results show that the proposed detection scheme ensures robust communications over 10-kilometre underwater acoustic channels with the data rate at 5 Kbits/s in 3 kHz of channel bandwidth.

Silent communication: toward using brain signals.

Science.gov (United States)

Pei, Xiaomei; Hill, Jeremy; Schalk, Gerwin

2012-01-01

From the 1980s movie Firefox to the more recent Avatar, popular science fiction has speculated about the possibility of a persons thoughts being read directly from his or her brain. Such braincomputer interfaces (BCIs) might allow people who are paralyzed to communicate with and control their environment, and there might also be applications in military situations wherever silent user-to-user communication is desirable. Previous studies have shown that BCI systems can use brain signals related to movements and movement imagery or attention-based character selection. Although these systems have successfully demonstrated the possibility to control devices using brain function, directly inferring which word a person intends to communicate has been elusive. A BCI using imagined speech might provide such a practical, intuitive device. Toward this goal, our studies to date addressed two scientific questions: (1) Can brain signals accurately characterize different aspects of speech? (2) Is it possible to predict spoken or imagined words or their components using brain signals?

Battlefield acoustics

CERN Document Server

Damarla, Thyagaraju

2015-01-01

This book presents all aspects of situational awareness in a battlefield using acoustic signals. It starts by presenting the science behind understanding and interpretation of sound signals. The book then goes on to provide various signal processing techniques used in acoustics to find the direction of sound source, localize gunfire, track vehicles, and detect people. The necessary mathematical background and various classification and fusion techniques are presented. The book contains majority of the things one would need to process acoustic signals for all aspects of situational awareness in one location. The book also presents array theory, which is pivotal in finding the direction of arrival of acoustic signals. In addition, the book presents techniques to fuse the information from multiple homogeneous/heterogeneous sensors for better detection. MATLAB code is provided for majority of the real application, which is a valuable resource in not only understanding the theory but readers, can also use the code...

Acoustics of fish shelters: background noise and signal-to-noise ratio.

Science.gov (United States)

Lugli, Marco

2014-12-01

Fish shelters (flat stones, shells, artificial covers, etc., with a hollow beneath) increase the sound pressure levels of low frequency sounds (noise ratio (SNR) in the nest. Background noise amplification by the shelter was examined under both laboratory (stones and shells) and field (stones) conditions, and the SNR of tones inside the nest cavity was measured by performing acoustic tests on stones in the stream. Stone and shell shelters amplify the background noise pressure levels inside the cavity with comparable gains and at similar frequencies of an active sound source. Inside the cavity of stream stones, the mean SNR of tones increased significantly below 125 Hz and peaked at 65 Hz (+10 dB). Implications for fish acoustic communication inside nest enclosures are discussed.

Background noise of acoustic emission signals in sodium piping loop

International Nuclear Information System (INIS)

Mori, Y.; Aoki, K.; Kuribayashi, K.; Kishi, T.; Sakakibara, Y.

1985-01-01

Background noise measurement in the frequency range of acoustic emission (AE) signals was made on the sodium piping loops of a 50 MW steam generator test facility in the Power Reactor and Nuclear Fuel Development Corporation (PNC). During the dynamic characteristics test of the steam generator over a wide range of operating conditions, the background noise generated on the pipe surface was measured using wideband AE sensor externally mounted with waveguide. Data were obtained for the effect of power loads of steam generator on both amplitude and frequency spectra of background noise signals. Source and nature of background noise were established

The ecology and evolution of avian alarm call signaling systems

Science.gov (United States)

Billings, Alexis Chandon

Communication is often set up as a simple dyadic exchange between one sender and one receiver. However, in reality, signaling systems have evolved and are used with many forms and types of information bombarding multiple senders, who in turn send multiple signals of different modalities, through various environmental spaces, finally reaching multiple receivers. In order to understand both the ecology and evolution of a signaling system, we must examine all the facets of the signaling system. My dissertation focused on the alarm call signaling system in birds. Alarm calls are acoustic signals given in response to danger or predators. My first two chapters examine how information about predators alters alarm calls. In chapter one I found that chickadees make distinctions between predators of different hunting strategies and appear to encode information about predators differently if they are heard instead of seen. In my second chapter, I test these findings more robustly in a non-model bird, the Steller's jay. I again found that predator species matters, but that how Steller's jays respond if they saw or heard the predator depends on the predator species. In my third chapter, I tested how habitat has influenced the evolution of mobbing call acoustic structure. I found that habitat is not a major contributor to the variation in acoustic structure seen across species and that other selective pressures such as body size may be more important. In my fourth chapter I present a new framework to understand the evolution of multimodal communication across species. I identify a unique constraint, the need for overlapping sensory systems, thresholds and cognitive abilities between sender and receiver in order for different forms of interspecific communication to evolve. Taken together, these chapters attempt to understand a signaling system from both an ecological and evolutionary perspective by examining each piece of the communication scheme.

Acoustic signals in the sand fly Lutzomyia (Nyssomyia) intermedia (Diptera: Psychodidae).

Science.gov (United States)

Vigoder, Felipe M; Souza, Nataly A; Peixoto, Alexandre A

2011-05-13

Acoustic signals are part of the courtship of many insects and they often act as species-specific signals that are important in the reproductive isolation of closely related species. Here we report the courtship songs of the sand fly Lutzomyia (Nyssomyia) intermedia, one of the main vectors of cutaneous leishmaniasis in Brazil. Recordings were performed using insects from three localities from Eastern Brazil: Posse and Jacarepaguá in Rio de Janeiro State and Corte de Pedra in Bahia State. The three areas have remnants of the Brazilian Atlantic forest, they are endemic for cutaneous leishmaniasis and L. intermedia is the predominant sand fly species. We observed that during courtship L. intermedia males from all populations produced pulse songs consisting of short trains. No significant differences in song parameters were observed between the males of the three localities. L. intermedia males produce acoustic signals as reported for some other sand flies such as the sibling species of the Lutzomyia longipalpis complex. The lack of differences between the males from the three localities is consistent with previous molecular studies of the period gene carried out in the same populations, reinforcing the idea that L. intermedia is not a species complex in the studied areas and that the three populations are likely to have similar vectorial capacities.

How acoustic signals scale with individual body size: common trends across diverse taxa

OpenAIRE

Rafael L. Rodríguez; Marcelo Araya-Salas; David A. Gray; Michael S. Reichert; Laurel B. Symes; Matthew R. Wilkins; Rebecca J. Safran; Gerlinde Höbel

2015-01-01

We use allometric analysis to explore how acoustic signals scale on individual body size and to test hypotheses about the factors shaping relationships between signals and body size. Across case studies spanning birds, crickets, tree crickets, and tree frogs, we find that most signal traits had low coefficients of variation, shallow allometric scalings, and little dispersion around the allometric function. We relate variation in these measures to the shape of mate preferences and the level of...

Brief communication "Seismic and acoustic-gravity signals from the source of the 2004 Indian Ocean Tsunami"

Directory of Open Access Journals (Sweden)

A. Raveloson

2012-02-01

Full Text Available The great Sumatra-Andaman earthquake of 26 December 2004 caused seismic waves propagating through the solid Earth, tsunami waves propagating through the ocean and infrasound or acoustic-gravity waves propagating through the atmosphere. Since the infrasound wave travels faster than its associated tsunami, it is for warning purposes very intriguing to study the possibility of infrasound generation directly at the earthquake source. Garces et al. (2005 and Le Pichon et al. (2005 emphasized that infrasound was generated by mountainous islands near the epicenter and by tsunami propagation along the continental shelf to the Bay of Bengal. Mikumo et al. (2008 concluded from the analysis of travel times and amplitudes of first arriving acoustic-gravity waves with periods of about 400–700 s that these waves are caused by coseismic motion of the sea surface mainly to the west of the Nicobar islands in the open seas. We reanalyzed the acoustic-gravity waves and corrected the first arrival times of Mikumo et al. (2008 by up to 20 min. We found the source of the first arriving acoustic-gravity wave about 300 km to the north of the US Geological Survey earthquake epicenter. This confirms the result of Mikumo et al. (2008 that sea level changes at the earthquake source cause long period acoustic-gravity waves, which indicate that a tsunami was generated. Therefore, a denser local network of infrasound stations may be helpful for tsunami warnings, not only for very large earthquakes.

Analysis of acoustic emission signals of fatigue crack growth and corrosion processes. Investigation of the possibilities for continuous condition monitoring of transport containers by acoustic emission testing

International Nuclear Information System (INIS)

Wachsmuth, Janne

2016-01-01

Fatigue crack growth and active corrosion processes are the main causes of structural failures of transport products like road tankers, railway tank cars and ships. To prevent those failures, preventive, time-based maintenance is performed. However, preventive inspections are costly and include the risk of not detecting a defect, which could lead to a failure within the next service period. An alternative is the idea of continuous monitoring of the whole structure by means of acoustic emission testing (AT). With AT, defects within the material shall be detected and repaired directly after their appearance. Acoustic emission testing is an online non-destructive testing method. Acoustic emission (AE) arises from changes within the material and is transported by elastic waves through the material. If the AE event generates enough energy, the elastic wave propagates to the boundaries of the component, produces a displacement in the picometre scale and can be detected by a piezoelectric sensor. The sensor produces an electrical signal. From this AE signal, AE features such as the maximum amplitude or the frequency can be extracted. Methods of signal analysis are used to investigate the time and frequency dependency of signal groups. The purpose of the signal analysis is to connect the AE signal with the originating AE source. If predefined damage mechanisms are identified, referencing the damage condition of the structure is possible. Acoustic emission from events of the actual crack propagation process can for example lead to the crack growth rate or the stress intensity factor, both specific values from fracture mechanics. A new development in the domain of acoustic emission testing is the pattern recognition of AE signals. Specific features are extracted from the AE signals to assign them to their damage mechanisms. In this thesis the AE signals from the damage mechanisms corrosion and fatigue crack growth are compared and analysed. The damage mechanisms were

Amélioration des performances du traitement des interférences dans le domaine fréquentiel pour les communications acoustiques sous marines

OpenAIRE

YOUCEF , Abdelhakim

2013-01-01

Underwater acoustic (UWA) communications allow wireless transmission between the surface and the bottom of a subsea environment based on acoustic waves. The wireless acoustic link reduces the physical infrastructure cost compared to the cable-based underwater communications. However, underwater acoustic channel imposes severe degradations on the transmitted signal. Its propagation characteristics are widely different from those of the radio channel. The multipath propagation caused by multipl...

Acoustics, information, and communication memorial volume in honor of Manfred R. Schroeder

CERN Document Server

Sessler, Gerhard

2015-01-01

This book explores the life and scientific legacy of Manfred Schroeder through personal reflections, scientific essays, and Schroeder’s own memoirs. Reflecting the wide range of Schroeder’s activities, the first part of the book contains thirteen articles written by his colleagues and former students. Topics discussed include his early, pioneering contributions to the understanding of statistical room acoustics and to the measurement of reverberation time; his introduction of digital signal processing methods into acoustics; his use of ray tracing methods to study sound decay in rooms; and his achievements in echo and feedback suppression and in noise reduction. Other chapters cover his seminal research in speech processing including the use of predictive coding to reduce audio bandwidth which led to various code-excited linear prediction schemes, today used extensively for speech coding. Several chapters discuss Schroeder’s work in low-peak factor signals, number theory, and maximum-length sequences wi...

Paternal Effort in Relation to Acoustically Mediated Mate Choice in a Neotropical Frog

Science.gov (United States)

Pettitt, Beth Ann

One aspect of communication not normally considered in studies of anuran amphibians involves the extent to which acoustic signals indicate the quality of parental care a male provides. My research examined this question in the golden rocket frog (Anomaloglossus beebei), a Neotropical dendrobatid that exhibits acoustically mediated mate choice and biparental care. I investigated the function of the male advertisement call of A. beebei in the context of female mate choice by testing the predictions of four hypotheses that have been proposed to explain the relationship between mate signals and male parental care quality. In addition, I conducted a series of studies on acoustic variability, female preferences for advertisement call traits and the importance of male parental care on offspring survival.

Design and Analysis of Underwater Acoustic Networks with Reflected Links

Science.gov (United States)

Emokpae, Lloyd

Underwater acoustic networks (UWANs) have applications in environmental state monitoring, oceanic profile measurements, leak detection in oil fields, distributed surveillance, and navigation. For these applications, sets of nodes are employed to collaboratively monitor an area of interest and track certain events or phenomena. In addition, it is common to find autonomous underwater vehicles (AUVs) acting as mobile sensor nodes that perform search-and-rescue missions, reconnaissance in combat zones, and coastal patrol. These AUVs are to work cooperatively to achieve a desired goal and thus need to be able to, in an ad-hoc manner, establish and sustain communication links in order to ensure some desired level of quality of service. Therefore, each node is required to adapt to environmental changes and be able to overcome broken communication links caused by external noise affecting the communication channel due to node mobility. In addition, since radio waves are quickly absorbed in the water medium, it is common for most underwater applications to rely on acoustic (or sound) rather than radio channels for mid-to-long range communications. However, acoustic channels pose multiple challenging issues, most notably the high transmission delay due to slow signal propagation and the limited channel bandwidth due to high frequency attenuation. Moreover, the inhomogeneous property of the water medium affects the sound speed profile while the signal surface and bottom reflections leads to multipath effects. In this dissertation, we address these networking challenges by developing protocols that take into consideration the underwater physical layer dynamics. We begin by introducing a novel surface-based reflection scheme (SBR), which takes advantage of the multipath effects of the acoustic channel. SBR works by using reflections from the water surface, and bottom, to establish non-line-of-sight (NLOS) communication links. SBR makes it possible to incorporate both line

The Research on Improved Companding Transformation for Reducing PAPR in Underwater Acoustic OFDM Communication System

Directory of Open Access Journals (Sweden)

Jinqiu Wu

2016-01-01

Full Text Available To solve the problem of the high peak-to-average power ratio (PAPR in Orthogonal Frequency Division Multiplexing (OFDM for the underwater acoustic communication system, the paper offers a method of reducing PAPR which combines the amplitude limiting and the improved nonlinear transformation. Traditional amplitude limiting technique can reduce PAPR in OFDM system effectively, at the cost of reducing the bit error rate (BER. However the companding transformation has far less computation complexity than SLM or PTS technologies and can improve the BER performance compared to the amplitude limiting technique simultaneously. The paper combines these two kinds of techniques, takes full use of advantages of the two method, and puts forward a low-complexity scheme choosing parameters that are more appropriate to the underwater acoustic field, with the result of improved BER performance even in lower SNR. Both simulation and experiment results show that the new method which combines clipping and companding transformation can effectively reduce the PAPR in the underwater acoustic OFDM communication system and improve the BER performance simultaneously.

Mate call as reward: Acoustic communication signals can acquire positive reinforcing values during adulthood in female zebra finches (Taeniopygia guttata).

Science.gov (United States)

Hernandez, Alexandra M; Perez, Emilie C; Mulard, Hervé; Mathevon, Nicolas; Vignal, Clémentine

2016-02-01

Social stimuli can have rewarding properties and promote learning. In birds, conspecific vocalizations like song can act as a reinforcer, and specific song variants can acquire particular rewarding values during early life exposure. Here we ask if, during adulthood, an acoustic signal simpler and shorter than song can become a reward for a female songbird because of its particular social value. Using an operant choice apparatus, we showed that female zebra finches display a preferential response toward their mate's calls. This reinforcing value of mate's calls could be involved in the maintenance of the monogamous pair-bond of the zebra finch. (c) 2016 APA, all rights reserved).

Characteristics of Acceleration and Acoustic Emission Signals from Mechanical Seals

International Nuclear Information System (INIS)

Lee, Do Hwan; Ha, Che Woong

2015-01-01

Based on these results, the applicability of acceleration signals for condition monitoring of mechanical seals is examined in the present study. Mechanical seals are used for pumps to prevent excessive leakage that might be occurred between rotational and stationary parts. The mechanical seals account for the major pump component failures. In spite of its importance, there have been few studies on condition monitoring of the components. Recently, some researchers have paid attention to the application of acoustic emission (AE) sensors for the fault detection of seals. The characteristics of acceleration and AE signals obtained from various defects are investigated. In order to prevent excessive leakage from mechanical seals, a condition monitoring technique is necessary. Based on the previous studies on AE techniques for seal monitoring, the signal characteristics from accelerometer

Characteristics of Acceleration and Acoustic Emission Signals from Mechanical Seals

Energy Technology Data Exchange (ETDEWEB)

Lee, Do Hwan; Ha, Che Woong [KHNP Central Research Institute, Daejeon (Korea, Republic of)

2015-10-15

Based on these results, the applicability of acceleration signals for condition monitoring of mechanical seals is examined in the present study. Mechanical seals are used for pumps to prevent excessive leakage that might be occurred between rotational and stationary parts. The mechanical seals account for the major pump component failures. In spite of its importance, there have been few studies on condition monitoring of the components. Recently, some researchers have paid attention to the application of acoustic emission (AE) sensors for the fault detection of seals. The characteristics of acceleration and AE signals obtained from various defects are investigated. In order to prevent excessive leakage from mechanical seals, a condition monitoring technique is necessary. Based on the previous studies on AE techniques for seal monitoring, the signal characteristics from accelerometer.

Spatial Modulation in the Underwater Acoustic Communication Channel

National Research Council Canada - National Science Library

Kilfoyle, Daniel

2000-01-01

.... The technique, termed spatial modulation, seeks to control the spatial distribution of signal energy such that multiple parallel communication channels are supported by the single, physical ocean channel...

Adaptive plasticity in wild field cricket's acoustic signaling.

Directory of Open Access Journals (Sweden)

Susan M Bertram

Full Text Available Phenotypic plasticity can be adaptive when phenotypes are closely matched to changes in the environment. In crickets, rhythmic fluctuations in the biotic and abiotic environment regularly result in diel rhythms in density of sexually active individuals. Given that density strongly influences the intensity of sexual selection, we asked whether crickets exhibit plasticity in signaling behavior that aligns with these rhythmic fluctuations in the socio-sexual environment. We quantified the acoustic mate signaling behavior of wild-caught males of two cricket species, Gryllus veletis and G. pennsylvanicus. Crickets exhibited phenotypically plastic mate signaling behavior, with most males signaling more often and more attractively during the times of day when mating activity is highest in the wild. Most male G. pennsylvanicus chirped more often and louder, with shorter interpulse durations, pulse periods, chirp durations, and interchirp durations, and at slightly higher carrier frequencies during the time of the day that mating activity is highest in the wild. Similarly, most male G. veletis chirped more often, with more pulses per chirp, longer interpulse durations, pulse periods, and chirp durations, shorter interchirp durations, and at lower carrier frequencies during the time of peak mating activity in the wild. Among-male variation in signaling plasticity was high, with some males signaling in an apparently maladaptive manner. Body size explained some of the among-male variation in G. pennsylvanicus plasticity but not G. veletis plasticity. Overall, our findings suggest that crickets exhibit phenotypically plastic mate attraction signals that closely match the fluctuating socio-sexual context they experience.

Acoustic signals in the sand fly Lutzomyia (Nyssomyia intermedia (Diptera: Psychodidae

Directory of Open Access Journals (Sweden)

Peixoto Alexandre A

2011-05-01

Full Text Available Abstract Background Acoustic signals are part of the courtship of many insects and they often act as species-specific signals that are important in the reproductive isolation of closely related species. Here we report the courtship songs of the sand fly Lutzomyia (Nyssomyia intermedia, one of the main vectors of cutaneous leishmaniasis in Brazil. Findings Recordings were performed using insects from three localities from Eastern Brazil: Posse and Jacarepaguá in Rio de Janeiro State and Corte de Pedra in Bahia State. The three areas have remnants of the Brazilian Atlantic forest, they are endemic for cutaneous leishmaniasis and L. intermedia is the predominant sand fly species. We observed that during courtship L. intermedia males from all populations produced pulse songs consisting of short trains. No significant differences in song parameters were observed between the males of the three localities. Conclusions L. intermedia males produce acoustic signals as reported for some other sand flies such as the sibling species of the Lutzomyia longipalpis complex. The lack of differences between the males from the three localities is consistent with previous molecular studies of the period gene carried out in the same populations, reinforcing the idea that L. intermedia is not a species complex in the studied areas and that the three populations are likely to have similar vectorial capacities.

Acoustic signals in the sand fly Lutzomyia (Nyssomyia) intermedia (Diptera: Psychodidae)

Science.gov (United States)

2011-01-01

Background Acoustic signals are part of the courtship of many insects and they often act as species-specific signals that are important in the reproductive isolation of closely related species. Here we report the courtship songs of the sand fly Lutzomyia (Nyssomyia) intermedia, one of the main vectors of cutaneous leishmaniasis in Brazil. Findings Recordings were performed using insects from three localities from Eastern Brazil: Posse and Jacarepaguá in Rio de Janeiro State and Corte de Pedra in Bahia State. The three areas have remnants of the Brazilian Atlantic forest, they are endemic for cutaneous leishmaniasis and L. intermedia is the predominant sand fly species. We observed that during courtship L. intermedia males from all populations produced pulse songs consisting of short trains. No significant differences in song parameters were observed between the males of the three localities. Conclusions L. intermedia males produce acoustic signals as reported for some other sand flies such as the sibling species of the Lutzomyia longipalpis complex. The lack of differences between the males from the three localities is consistent with previous molecular studies of the period gene carried out in the same populations, reinforcing the idea that L. intermedia is not a species complex in the studied areas and that the three populations are likely to have similar vectorial capacities. PMID:21569534

Acoustic signal generation in excised muscle by pulsed proton beam irradiation and the possibility of its clinical application to radiation therapy

International Nuclear Information System (INIS)

Hayakawa, Yoshinori; Tada, Junichiro; Inada, Tetsuo; Kitagawa, Toshio; Wagai, Toshio; Yoshioka, Katsuya.

1989-01-01

Acoustic signals generated in liquids and in metals by pulsed proton beam are thought to be thermal shock wave due to localized energy deposition of incident protons. Thus the intensity of generated acoustic signals is almost proportional to the energy deposited at the region. This suggests the possibility for measuring spatial distribution of energy deposition of proton beam using the acoustic method. In proton beam radiation therapy, treatment planning is developed from data of X-ray computer tomography which reflects the information on the electron density distribution in the patient's body. Ensuring the agreement of the dose distribution in the patient with the planned one, however, is difficult. It is expected that the acoustic method can provide a useful tool for this purpose. The pulsed proton beam of 50ns in pulse width is used for cancer therapy at the University of Tsukuba. A hydrophone is used to detect acoustic signals generated by pulsed proton beam. Detected signals are amplified ten thousand times before being averaged and analyzed by digital oscilloscope. Measurements made suggest that the method could be useful for radiation therapy. (N.K.)

All-optical signal processing data communication and storage applications

CERN Document Server

Eggleton, Benjamin

2015-01-01

This book provides a comprehensive review of the state-of-the art of optical signal processing technologies and devices. It presents breakthrough solutions for enabling a pervasive use of optics in data communication and signal storage applications. It presents presents optical signal processing as solution to overcome the capacity crunch in communication networks. The book content ranges from the development of innovative materials and devices, such as graphene and slow light structures, to the use of nonlinear optics for secure quantum information processing and overcoming the classical Shannon limit on channel capacity and microwave signal processing. Although it holds the promise for a substantial speed improvement, today’s communication infrastructure optics remains largely confined to the signal transport layer, as it lags behind electronics as far as signal processing is concerned. This situation will change in the near future as the tremendous growth of data traffic requires energy efficient and ful...

2012 Proceedings of the International Conference on Communications, Signal Processing, and Systems

CERN Document Server

Wang, Wei; Mu, Jiasong; Liang, Jing; Zhang, Baoju; Pi, Yiming; Zhao, Chenglin

2012-01-01

Communications, Signal Processing, and Systems is a collection of contributions coming out of the International Conference on Communications, Signal Processing, and Systems (CSPS) held October 2012. This book provides the state-of-art developments of Communications, Signal Processing, and Systems, and their interactions in multidisciplinary fields, such as Smart Grid. The book also examines Radar Systems, Sensor Networks, Radar Signal Processing, Design and Implementation of Signal Processing Systems and Applications. Written by experts and students in the fields of Communications, Signal Processing, and Systems.

The Acoustic Emission in the Nest of the Honey Bee Depending on the Extreme Weather Conditions

Directory of Open Access Journals (Sweden)

Jaromír Tlačbaba

2014-01-01

Full Text Available The vibroacoustic signals are an important part of communication in the honey bees (Apis mellifera L.. The aim of this study was to observe the acoustic emission that varies in a bee colony during different weather phenomena (strong winds and hailstorms and to estimate the nature and the extent of the reactions of the colony by the analysis of the obtained data. Experiments were carried out in the volume-reduced hives. The specific weather phenomena were followed by significant (P < 0.0001 increasing of the intensity of the acoustic emission in the colony in comparison with acoustic emission before or after the phenomena. Close linear positive relationship was confirmed between the intensity of wind gusts and intensity of acoustic emission (r = 0.72; P < 0.001. With the increase in the maximum gust of 1 km·h−1, the intensity of acoustic emission increased by 0.1466 mV. The character and degree of reaction of the colony can be estimated with analysis of the measured data. Permeability of vibration signals directly induced weather phenomena through the construction of the experimental hive and the stress in the colony are discussed. Observation of the acoustic emission distributed within the colony is one of the methodical alternatives for research of the vibroacoustic communication in the colony.

Fatigue Level Estimation of Bill Based on Acoustic Signal Feature by Supervised SOM

Science.gov (United States)

Teranishi, Masaru; Omatu, Sigeru; Kosaka, Toshihisa

Fatigued bills have harmful influence on daily operation of Automated Teller Machine(ATM). To make the fatigued bills classification more efficient, development of an automatic fatigued bill classification method is desired. We propose a new method to estimate bending rigidity of bill from acoustic signal feature of banking machines. The estimated bending rigidities are used as continuous fatigue level for classification of fatigued bill. By using the supervised Self-Organizing Map(supervised SOM), we estimate the bending rigidity from only the acoustic energy pattern effectively. The experimental result with real bill samples shows the effectiveness of the proposed method.

Advanced Signal Processing for Wireless Multimedia Communications

Directory of Open Access Journals (Sweden)

Xiaodong Wang

2000-01-01

Full Text Available There is at present a worldwide effort to develop next-generation wireless communication systems. It is envisioned that many of the future wireless systems will incorporate considerable signal-processing intelligence in order to provide advanced services such as multimedia transmission. In general, wireless channels can be very hostile media through which to communicate, due to substantial physical impediments, primarily radio-frequency interference and time-arying nature of the channel. The need of providing universal wireless access at high data-rate (which is the aim of many merging wireless applications presents a major technical challenge, and meeting this challenge necessitates the development of advanced signal processing techniques for multiple-access communications in non-stationary interference-rich environments. In this paper, we present some key advanced signal processing methodologies that have been developed in recent years for interference suppression in wireless networks. We will focus primarily on the problem of jointly suppressing multiple-access interference (MAI and intersymbol interference (ISI, which are the limiting sources of interference for the high data-rate wireless systems being proposed for many emerging application areas, such as wireless multimedia. We first present a signal subspace approach to blind joint suppression of MAI and ISI. We then discuss a powerful iterative technique for joint interference suppression and decoding, so-called Turbo multiuser detection, that is especially useful for wireless multimedia packet communications. We also discuss space-time processing methods that employ multiple antennas for interference rejection and signal enhancement. Finally, we touch briefly on the problems of suppressing narrowband interference and impulsive ambient noise, two other sources of radio-frequency interference present in wireless multimedia networks.

Preliminary study of acoustic emission (ae) noise signal identification for crude oil storage tank

International Nuclear Information System (INIS)

Nurul Ain Ahmad Latif; Shukri Mohd

2008-08-01

This preliminary work was carried out to simulate the Acoustic Emission (AE) signal contributed by pitting corrosion, and noise signal from environment during crude oil storage tanks monitoring. The purpose of this study is to prove that acoustic emission (AE) could be used to detect the formation of pitting corrosion in the crude oil storage tank and differentiated it from other sources of noise signal. In this study, the pitting corrosion was simulated by inducing low voltage and low amperage current onto the crude oil storage tank material (ASTM 516 G 70). Water drop, air blow and surface rubbing were applied onto the specimen surface. To simulate the noise signal produce by rain fall, wind blow and other sources of noise during AE crude oil storage tanks monitoring. AE sensor was attached onto the other surface of specimen to acquire all of these AE signals which then has send to AE DiSP 24 data acquisition system for signal conditioning. AE win software has been used to analyse this entire signal. It is found that, simulated pitting corrosion could be detected by AE system and differentiated from other sources of noise by using amplitude analysis. From the amplitude analysis is shown that 20-30 dB is the range amplitude for the blow test, 50-60 dB for surface rubbing test and over than 60 dB for water drop test. (Author)

Demodulation of acoustic telemetry binary phase shift keying signal based on high-order Duffing system

International Nuclear Information System (INIS)

Yan Bing-Nan; Liu Chong-Xin; Ni Jun-Kang; Zhao Liang

2016-01-01

In order to grasp the downhole situation immediately, logging while drilling (LWD) technology is adopted. One of the LWD technologies, called acoustic telemetry, can be successfully applied to modern drilling. It is critical for acoustic telemetry technology that the signal is successfully transmitted to the ground. In this paper, binary phase shift keying (BPSK) is used to modulate carrier waves for the transmission and a new BPSK demodulation scheme based on Duffing chaos is investigated. Firstly, a high-order system is given in order to enhance the signal detection capability and it is realized through building a virtual circuit using an electronic workbench (EWB). Secondly, a new BPSK demodulation scheme is proposed based on the intermittent chaos phenomena of the new Duffing system. Finally, a system variable crossing zero-point equidistance method is proposed to obtain the phase difference between the system and the BPSK signal. Then it is determined that the digital signal transmitted from the bottom of the well is ‘0’ or ‘1’. The simulation results show that the demodulation method is feasible. (paper)

Predators are attracted to the olfactory signals of prey.

Directory of Open Access Journals (Sweden)

Nelika K Hughes

2010-09-01

Full Text Available Predator attraction to prey social signals can force prey to trade-off the social imperatives to communicate against the profound effect of predation on their future fitness. These tradeoffs underlie theories on the design and evolution of conspecific signalling systems and have received much attention in visual and acoustic signalling modes. Yet while most territorial mammals communicate using olfactory signals and olfactory hunting is widespread in predators, evidence for the attraction of predators to prey olfactory signals under field conditions is lacking.To redress this fundamental issue, we examined the attraction of free-roaming predators to discrete patches of scents collected from groups of two and six adult, male house mice, Mus domesticus, which primarily communicate through olfaction. Olfactorily-hunting predators were rapidly attracted to mouse scent signals, visiting mouse scented locations sooner, and in greater number, than control locations. There were no effects of signal concentration on predator attraction to their prey's signals.This implies that communication will be costly if conspecific receivers and eavesdropping predators are simultaneously attracted to a signal. Significantly, our results also suggest that receivers may be at greater risk of predation when communicating than signallers, as receivers must visit risky patches of scent to perform their half of the communication equation, while signallers need not.

YIP Expansion: Ocean Basin Impact of Ambient Noise on Marine Mammal Detectability, Distribution, and Acoustic Communication

Science.gov (United States)

2015-09-30

Marine Mammal Detectability, Distribution, and Acoustic Communication Jennifer L. Miksis-Olds Applied Research Laboratory The Pennsylvania State...relatively stereotyped calls, commonly considered types of automatic detection include spectrogram correlation and matched filtering. Spectrogram

Acoustic Signals Processing at the Realization of Contact-Difference Method for Person Identification

Directory of Open Access Journals (Sweden)

A. N. Golubinskiy

2011-09-01

Full Text Available The questions of speech and acoustic (registered on a human body at pronouncing by him of sounds signals processing are examined. The measure of a distinguish ability for identification at parameterization of a biometric image by an amplitude-frequency response of a human body is developed.

A comparative study of the SVM and K-nn machine learning algorithms for the diagnosis of respiratory pathologies using pulmonary acoustic signals.

Science.gov (United States)

Palaniappan, Rajkumar; Sundaraj, Kenneth; Sundaraj, Sebastian

2014-06-27

Pulmonary acoustic parameters extracted from recorded respiratory sounds provide valuable information for the detection of respiratory pathologies. The automated analysis of pulmonary acoustic signals can serve as a differential diagnosis tool for medical professionals, a learning tool for medical students, and a self-management tool for patients. In this context, we intend to evaluate and compare the performance of the support vector machine (SVM) and K-nearest neighbour (K-nn) classifiers in diagnosis respiratory pathologies using respiratory sounds from R.A.L.E database. The pulmonary acoustic signals used in this study were obtained from the R.A.L.E lung sound database. The pulmonary acoustic signals were manually categorised into three different groups, namely normal, airway obstruction pathology, and parenchymal pathology. The mel-frequency cepstral coefficient (MFCC) features were extracted from the pre-processed pulmonary acoustic signals. The MFCC features were analysed by one-way ANOVA and then fed separately into the SVM and K-nn classifiers. The performances of the classifiers were analysed using the confusion matrix technique. The statistical analysis of the MFCC features using one-way ANOVA showed that the extracted MFCC features are significantly different (p < 0.001). The classification accuracies of the SVM and K-nn classifiers were found to be 92.19% and 98.26%, respectively. Although the data used to train and test the classifiers are limited, the classification accuracies found are satisfactory. The K-nn classifier was better than the SVM classifier for the discrimination of pulmonary acoustic signals from pathological and normal subjects obtained from the RALE database.

Demystifying communication signal lost for network redundancy ...

African Journals Online (AJOL)

These studies report on the communication signal lost factors that were analyzed and supported by evidences on coverage analysis activities for Automatic Meter Reading (AMR) systems. We have categorized the influential signal lost factors into four core elements that were concluded based on our field measurement ...

Multiuser underwater acoustic communication using single-element virtual time reversal mirror

Institute of Scientific and Technical Information of China (English)

YIN JingWei; WANG YiLin; WANG Lei; HUI JunYing

2009-01-01

Pattern time delay shift coding (PDS) scheme is introduced and combined with spread spectrum tech-nique called SS-PDS for short which is power-saving and competent for long-range underwater acous-tic networks.Single-element virtual time reversal mirror (VTRM) is presented in this paper and validated by the lake trial results.Employing single-element VTRM in multiuser communication system based on SS-PDS can separate different users' information simultaneously at master node as indicated in the simulation results.

Acoustic imaging system

Science.gov (United States)

Smith, Richard W.

1979-01-01

An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.

Contribution to automatic speech recognition. Analysis of the direct acoustical signal. Recognition of isolated words and phoneme identification

International Nuclear Information System (INIS)

Dupeyrat, Benoit

1981-01-01

This report deals with the acoustical-phonetic step of the automatic recognition of the speech. The parameters used are the extrema of the acoustical signal (coded in amplitude and duration). This coding method, the properties of which are described, is simple and well adapted to a digital processing. The quality and the intelligibility of the coded signal after reconstruction are particularly satisfactory. An experiment for the automatic recognition of isolated words has been carried using this coding system. We have designed a filtering algorithm operating on the parameters of the coding. Thus the characteristics of the formants can be derived under certain conditions which are discussed. Using these characteristics the identification of a large part of the phonemes for a given speaker was achieved. Carrying on the studies has required the development of a particular methodology of real time processing which allowed immediate evaluation of the improvement of the programs. Such processing on temporal coding of the acoustical signal is extremely powerful and could represent, used in connection with other methods an efficient tool for the automatic processing of the speech.(author) [fr

Intelligent acoustic data fusion technique for information security analysis

Science.gov (United States)

Jiang, Ying; Tang, Yize; Lu, Wenda; Wang, Zhongfeng; Wang, Zepeng; Zhang, Luming

2017-08-01

Tone is an essential component of word formation in all tonal languages, and it plays an important role in the transmission of information in speech communication. Therefore, tones characteristics study can be applied into security analysis of acoustic signal by the means of language identification, etc. In speech processing, fundamental frequency (F0) is often viewed as representing tones by researchers of speech synthesis. However, regular F0 values may lead to low naturalness in synthesized speech. Moreover, F0 and tone are not equivalent linguistically; F0 is just a representation of a tone. Therefore, the Electroglottography (EGG) signal is collected for deeper tones characteristics study. In this paper, focusing on the Northern Kam language, which has nine tonal contours and five level tone types, we first collected EGG and speech signals from six natural male speakers of the Northern Kam language, and then achieved the clustering distributions of the tone curves. After summarizing the main characteristics of tones of Northern Kam, we analyzed the relationship between EGG and speech signal parameters, and laid the foundation for further security analysis of acoustic signal.

Shared acoustic codes underlie emotional communication in music and speech-Evidence from deep transfer learning.

Science.gov (United States)

Coutinho, Eduardo; Schuller, Björn

2017-01-01

Music and speech exhibit striking similarities in the communication of emotions in the acoustic domain, in such a way that the communication of specific emotions is achieved, at least to a certain extent, by means of shared acoustic patterns. From an Affective Sciences points of view, determining the degree of overlap between both domains is fundamental to understand the shared mechanisms underlying such phenomenon. From a Machine learning perspective, the overlap between acoustic codes for emotional expression in music and speech opens new possibilities to enlarge the amount of data available to develop music and speech emotion recognition systems. In this article, we investigate time-continuous predictions of emotion (Arousal and Valence) in music and speech, and the Transfer Learning between these domains. We establish a comparative framework including intra- (i.e., models trained and tested on the same modality, either music or speech) and cross-domain experiments (i.e., models trained in one modality and tested on the other). In the cross-domain context, we evaluated two strategies-the direct transfer between domains, and the contribution of Transfer Learning techniques (feature-representation-transfer based on Denoising Auto Encoders) for reducing the gap in the feature space distributions. Our results demonstrate an excellent cross-domain generalisation performance with and without feature representation transfer in both directions. In the case of music, cross-domain approaches outperformed intra-domain models for Valence estimation, whereas for Speech intra-domain models achieve the best performance. This is the first demonstration of shared acoustic codes for emotional expression in music and speech in the time-continuous domain.

Energetic cost of communication.

Science.gov (United States)

Stoddard, Philip K; Salazar, Vielka L

2011-01-15

Communication signals may be energetically expensive or inexpensive to produce, depending on the function of the signal and the competitive nature of the communication system. Males of sexually selected species may produce high-energy advertisement signals, both to enhance detectability and to signal their size and body condition. Accordingly, the proportion of the energy budget allocated to signal production ranges from almost nothing for many signals to somewhere in excess of 50% for acoustic signals in short-lived sexually selected species. Recent data from gymnotiform electric fish reveal mechanisms that regulate energy allocated to sexual advertisement signals through dynamical remodeling of the excitable membranes in the electric organ. Further, males of the short-lived sexually selected species, Brachyhypopomus gauderio, trade off among different metabolic compartments, allocating energy to signal production while reducing energy used in other metabolic functions. Female B. gauderio, by contrast, do not trade off energy between signaling and other functions. To fuel energetically expensive signal production, we expect a continuum of strategies to be adopted by animals of different life history strategies. Future studies should explore the relation between life history and energy allocation trade-offs.

Listening to the Deep: live monitoring of ocean noise and cetacean acoustic signals.

Science.gov (United States)

André, M; van der Schaar, M; Zaugg, S; Houégnigan, L; Sánchez, A M; Castell, J V

2011-01-01

The development and broad use of passive acoustic monitoring techniques have the potential to help assessing the large-scale influence of artificial noise on marine organisms and ecosystems. Deep-sea observatories have the potential to play a key role in understanding these recent acoustic changes. LIDO (Listening to the Deep Ocean Environment) is an international project that is allowing the real-time long-term monitoring of marine ambient noise as well as marine mammal sounds at cabled and standalone observatories. Here, we present the overall development of the project and the use of passive acoustic monitoring (PAM) techniques to provide the scientific community with real-time data at large spatial and temporal scales. Special attention is given to the extraction and identification of high frequency cetacean echolocation signals given the relevance of detecting target species, e.g. beaked whales, in mitigation processes, e.g. during military exercises. Copyright © 2011. Published by Elsevier Ltd.

DOWNHOLE POWER GENERATION AND WIRELESS COMMUNICATIONS FOR INTELLIGENT COMPLETIONS APPLICATIONS

Energy Technology Data Exchange (ETDEWEB)

Paul Tubel

2003-10-14

The fourth quarter of the project was dedicated to the manufacturing of the mechanical system for wireless communications and the power generation module and inspection pre assembly of the mechanical components. Another emphasis for the quarter was the development of filter control and signal detection software. The tasks accomplished during this report period were: (1) Dimensional issues were resolved and revised drawings for manufacturing of the wireless communications gauge and power generator were completed and sent to a machine shop for manufacturing. (2) Finalized the requirements and fittings and connections for testing the tool in the Halliburton flow loop. (3) The new acoustic generator was manufactured successfully and it was delivered during this quarter. The assembly will be outsourced for plastic coating in preparation for hostile environment use. (4) The acoustic two-way communications development continued to progress. The real time firmware for the surface system was developed and the processor was able to detect and process the data frame transmitted from downhole. The analog section of the tool was also developed and it is being tested for filtering capabilities and signal detection and amplification. (5) The new transformer to drive the acoustic generator assembly was manufactured and was successfully tested. Spring mandrel design showed increased acoustic output on the pipe and was implemented. (6) PCBA board carrier with board set was tested for function and fit and is 100% complete. (7) Filter control software is complete and software to allow modification of communication parameters dynamically is 50% complete. (8) All mechanical parts to assemble the wireless gauge and power generator have been received and verified to be within specification. (9) Acoustic generator has been assembled in the tool mandrel and tested successfully. (10) The circuit required to harvest the power generated downhole has been designed and the power generator

Surface acoustic wave dust deposition monitor

Science.gov (United States)

Fasching, G.E.; Smith, N.S. Jr.

1988-02-12

A system is disclosed for using the attenuation of surface acoustic waves to monitor real time dust deposition rates on surfaces. The system includes a signal generator, a tone-burst generator/amplifier connected to a transmitting transducer for converting electrical signals into acoustic waves. These waves are transmitted through a path defining means adjacent to a layer of dust and then, in turn, transmitted to a receiving transducer for changing the attenuated acoustic wave to electrical signals. The signals representing the attenuated acoustic waves may be amplified and used in a means for analyzing the output signals to produce an output indicative of the dust deposition rates and/or values of dust in the layer. 8 figs.

Acoustic calibration apparatus for calibrating plethysmographic acoustic pressure sensors

Science.gov (United States)

Zuckerwar, Allan J. (Inventor); Davis, David C. (Inventor)

1995-01-01

An apparatus for calibrating an acoustic sensor is described. The apparatus includes a transmission material having an acoustic impedance approximately matching the acoustic impedance of the actual acoustic medium existing when the acoustic sensor is applied in actual in-service conditions. An elastic container holds the transmission material. A first sensor is coupled to the container at a first location on the container and a second sensor coupled to the container at a second location on the container, the second location being different from the first location. A sound producing device is coupled to the container and transmits acoustic signals inside the container.

Extruded Bread Classification on the Basis of Acoustic Emission Signal With Application of Artificial Neural Networks

Science.gov (United States)

Świetlicka, Izabela; Muszyński, Siemowit; Marzec, Agata

2015-04-01

The presented work covers the problem of developing a method of extruded bread classification with the application of artificial neural networks. Extruded flat graham, corn, and rye breads differening in water activity were used. The breads were subjected to the compression test with simultaneous registration of acoustic signal. The amplitude-time records were analyzed both in time and frequency domains. Acoustic emission signal parameters: single energy, counts, amplitude, and duration acoustic emission were determined for the breads in four water activities: initial (0.362 for rye, 0.377 for corn, and 0.371 for graham bread), 0.432, 0.529, and 0.648. For classification and the clustering process, radial basis function, and self-organizing maps (Kohonen network) were used. Artificial neural networks were examined with respect to their ability to classify or to cluster samples according to the bread type, water activity value, and both of them. The best examination results were achieved by the radial basis function network in classification according to water activity (88%), while the self-organizing maps network yielded 81% during bread type clustering.

Visible light communications modulation and signal processing

CERN Document Server

Wang, Zhaocheng; Huang, Wei; Xu, Zhengyuan

2018-01-01

This informative new book on state-of-the-art visible light communication (VLC) provides, for the first time, a systematical and advanced treatment of modulation and signal processing for VLC. Visible Light Communications: Modulation and Signal Processing offers a practical guide to designing VLC, linking academic research with commercial applications. In recent years, VLC has attracted attention from academia and industry since it has many advantages over the traditional radio frequency, including wide unregulated bandwidth, high security, and low cost. It is a promising complementary technique in 5G and beyond wireless communications, especially in indoor applications. However, lighting constraints have not been fully considered in the open literature when considering VLC system design, and its importance has been underestimated. That’s why this book—written by a team of experts with both academic research experience and industrial development experience in the field—is so welcome. To help readers u...

Selecting Informative Features of the Helicopter and Aircraft Acoustic Signals in the Adaptive Autonomous Information Systems for Recognition

Directory of Open Access Journals (Sweden)

V. K. Hohlov

2017-01-01

Full Text Available The article forms the rationale for selecting the informative features of the helicopter and aircraft acoustic signals to solve a problem of their recognition and shows that the most informative ones are the counts of extrema in the energy spectra of the input signals, which represent non-centered random variables. An apparatus of the multiple initial regression coefficients was selected as a mathematical tool of research. The application of digital re-circulators with positive and negative feedbacks, which have the comb-like frequency characteristics, solves the problem of selecting informative features. A distinguishing feature of such an approach is easy agility of the comb frequency characteristics just through the agility of a delay value of digital signal in the feedback circuit. Adding an adaptation block to the selection block of the informative features enables us to ensure the invariance of used informative feature and counts of local extrema of the spectral power density to the airspeed of a helicopter. The paper gives reasons for the principle of adaptation and the structure of the adaptation block. To form the discriminator characteristics are used the cross-correlation statistical characteristics of the quadrature components of acoustic signal realizations, obtained by Hilbert transform. The paper proposes to provide signal recognition using a regression algorithm that allows handling the non-centered informative features and using a priori information about coefficients of initial regression of signal and noise.The simulation in Matlab Simulink has shown that selected informative features of signals in regressive processing of signal realizations of 0.5 s duration have good separability, and based on a set of 100 acoustic signal realizations in each class in full-scale conditions, has proved ensuring a correct recognition probability of 0.975, at least. The considered principles of informative features selection and adaptation can

Advances in the ROBLINKS project on long-range shallow-water robust acoustic communciation links

NARCIS (Netherlands)

Gijzen, M.B. van; Walree, P.A. van; Cano, D.; Passerieux, J-M.; Waldhorst, A.; Weber, R.

2000-01-01

Within the ROBLINKS project waveforms and algorithms have been developed to establish robust underwater acoustic communication links with high data rates in shallow water. To evaluate the signalling schemes, a wide range of experiments has been performed during a sea trial that has been held in May

Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions.

Science.gov (United States)

Muhammed, Dalhatu; Anisi, Mohammad Hossein; Zareei, Mahdi; Vargas-Rosales, Cesar; Khan, Anwar

2018-02-01

Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal), long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node's cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted.

Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions

Directory of Open Access Journals (Sweden)

Dalhatu Muhammed

2018-02-01

Full Text Available Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal, long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node’s cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted.

Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions

Science.gov (United States)

Muhammed, Dalhatu; Anisi, Mohammad Hossein; Vargas-Rosales, Cesar; Khan, Anwar

2018-01-01

Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal), long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node’s cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted. PMID:29389874

Acoustic evolution in crickets: need for phylogenetic study and a reappraisal of signal effectiveness

Directory of Open Access Journals (Sweden)

Laure Desutter-Grandcolas

2004-06-01

Full Text Available Cricket stridulums and calls are highly stereotyped, except those with greatly modified tegmina and/or vena-tion, or ''unusual'' frequency, duration and/or intensity. This acoustic diversity remained unsuspected until recently, and current models of acoustic evolution in crickets erroneously consider this clade homogeneous for acoustic features. The few phylogenetic studies analyzing acoustic evolution in crickets demonstrated that acoustic behavior could be particularly labile in some clades. The ensuing pattern for cricket evolution is consequently extremely complex. We argue that: (1 phylogeny should always be considered when analyzing acoustic evolution, whatever characters are considered (signals, stridulums or behaviors. Consequently, future studies should be devoted to entire clades, and not consider isolated taxa; character and character state definitions should allow significant reconstructions of character evolutionary transformations; and homologies should be carefully defined for all characters, including behavior. (2 The factors responsible for song effectiveness should be reconsidered and hypotheses on their potential influence on signal evolution tested jointly by phylogenies (for example, to assess correlated transformations of acoustic and ecological features, and population studies (for example, to correlate call range and population structure, or test the predation risk associated with a signal structure. Better understanding these points should help clarifying acoustic evolution in crickets.Os aparelhos estridulatórios e os chamados dos grilos são altamente estereotipados, exceto aqueles com áreas e/ou venação tegminais fortemente modificadas ou com freqüência, duração e/ou intensidade fora do ''normal''. Esta diversidade acústica ficou insuspeita até recentemente, e os modelos correntes de evolução acústica em grilos consideram erroneamente este clado como homogêneo para as características acústicas. Os

Phylogenetic signal in the acoustic parameters of the advertisement calls of four clades of anurans.

Science.gov (United States)

Gingras, Bruno; Mohandesan, Elmira; Boko, Drasko; Fitch, W Tecumseh

2013-07-01

Anuran vocalizations, especially their advertisement calls, are largely species-specific and can be used to identify taxonomic affiliations. Because anurans are not vocal learners, their vocalizations are generally assumed to have a strong genetic component. This suggests that the degree of similarity between advertisement calls may be related to large-scale phylogenetic relationships. To test this hypothesis, advertisement calls from 90 species belonging to four large clades (Bufo, Hylinae, Leptodactylus, and Rana) were analyzed. Phylogenetic distances were estimated based on the DNA sequences of the 12S mitochondrial ribosomal RNA gene, and, for a subset of 49 species, on the rhodopsin gene. Mean values for five acoustic parameters (coefficient of variation of root-mean-square amplitude, dominant frequency, spectral flux, spectral irregularity, and spectral flatness) were computed for each species. We then tested for phylogenetic signal on the body-size-corrected residuals of these five parameters, using three statistical tests (Moran's I, Mantel, and Blomberg's K) and three models of genetic distance (pairwise distances, Abouheif's proximities, and the variance-covariance matrix derived from the phylogenetic tree). A significant phylogenetic signal was detected for most acoustic parameters on the 12S dataset, across statistical tests and genetic distance models, both for the entire sample of 90 species and within clades in several cases. A further analysis on a subset of 49 species using genetic distances derived from rhodopsin and from 12S broadly confirmed the results obtained on the larger sample, indicating that the phylogenetic signals observed in these acoustic parameters can be detected using a variety of genetic distance models derived either from a variable mitochondrial sequence or from a conserved nuclear gene. We found a robust relationship, in a large number of species, between anuran phylogenetic relatedness and acoustic similarity in the

A technique for the deconvolution of the pulse shape of acoustic emission signals back to the generating defect source

International Nuclear Information System (INIS)

Houghton, J.R.; Packman, P.F.; Townsend, M.A.

1976-01-01

Acoustic emission signals recorded after passage through the instrumentation system can be deconvoluted to produce signal traces indicative of those at the generating source, and these traces can be used to identify characteristics of the source

Signal Conditioning An Introduction to Continuous Wave Communication and Signal Processing

CERN Document Server

Das, Apurba

2012-01-01

"Signal Conditioning” is a comprehensive introduction to electronic signal processing. The book presents the mathematical basics including the implications of various transformed domain representations in signal synthesis and analysis in an understandable and lucid fashion and illustrates the theory through many applications and examples from communication systems. The ease to learn is supported by well-chosen exercises which give readers the flavor of the subject. Supplementary electronic materials available on http://extras.springer.com including MATLAB codes illuminating applications in the domain of one dimensional electrical signal processing, image processing and speech processing. The book is an introduction for students with a basic understanding in engineering or natural sciences.

Acoustic Signal Characteristics Measured with the LAMBDA III During CHURCH STROKE III

Science.gov (United States)

1980-09-15

analysis. Dr. William M. Carey and Dr. Richard Doolittle participated in various stages of acquisition, processing and analysis of the information...reported herein. Drs. Carey , Doolittle and Mr. Gereben are the authors of this report. (U) This report: Acoustic Signal Characteristics Measured with... Tortugas Terrace and the East Yucatan Channel,the Catoche Tongue and the Eastern region of the Gulf of Mexico. (U) The exercise was conducted by the Long

Shared acoustic codes underlie emotional communication in music and speech-Evidence from deep transfer learning.

Directory of Open Access Journals (Sweden)

Eduardo Coutinho

Full Text Available Music and speech exhibit striking similarities in the communication of emotions in the acoustic domain, in such a way that the communication of specific emotions is achieved, at least to a certain extent, by means of shared acoustic patterns. From an Affective Sciences points of view, determining the degree of overlap between both domains is fundamental to understand the shared mechanisms underlying such phenomenon. From a Machine learning perspective, the overlap between acoustic codes for emotional expression in music and speech opens new possibilities to enlarge the amount of data available to develop music and speech emotion recognition systems. In this article, we investigate time-continuous predictions of emotion (Arousal and Valence in music and speech, and the Transfer Learning between these domains. We establish a comparative framework including intra- (i.e., models trained and tested on the same modality, either music or speech and cross-domain experiments (i.e., models trained in one modality and tested on the other. In the cross-domain context, we evaluated two strategies-the direct transfer between domains, and the contribution of Transfer Learning techniques (feature-representation-transfer based on Denoising Auto Encoders for reducing the gap in the feature space distributions. Our results demonstrate an excellent cross-domain generalisation performance with and without feature representation transfer in both directions. In the case of music, cross-domain approaches outperformed intra-domain models for Valence estimation, whereas for Speech intra-domain models achieve the best performance. This is the first demonstration of shared acoustic codes for emotional expression in music and speech in the time-continuous domain.

Shared acoustic codes underlie emotional communication in music and speech—Evidence from deep transfer learning

Science.gov (United States)

Schuller, Björn

2017-01-01

Music and speech exhibit striking similarities in the communication of emotions in the acoustic domain, in such a way that the communication of specific emotions is achieved, at least to a certain extent, by means of shared acoustic patterns. From an Affective Sciences points of view, determining the degree of overlap between both domains is fundamental to understand the shared mechanisms underlying such phenomenon. From a Machine learning perspective, the overlap between acoustic codes for emotional expression in music and speech opens new possibilities to enlarge the amount of data available to develop music and speech emotion recognition systems. In this article, we investigate time-continuous predictions of emotion (Arousal and Valence) in music and speech, and the Transfer Learning between these domains. We establish a comparative framework including intra- (i.e., models trained and tested on the same modality, either music or speech) and cross-domain experiments (i.e., models trained in one modality and tested on the other). In the cross-domain context, we evaluated two strategies—the direct transfer between domains, and the contribution of Transfer Learning techniques (feature-representation-transfer based on Denoising Auto Encoders) for reducing the gap in the feature space distributions. Our results demonstrate an excellent cross-domain generalisation performance with and without feature representation transfer in both directions. In the case of music, cross-domain approaches outperformed intra-domain models for Valence estimation, whereas for Speech intra-domain models achieve the best performance. This is the first demonstration of shared acoustic codes for emotional expression in music and speech in the time-continuous domain. PMID:28658285

Fractal Complexity-Based Feature Extraction Algorithm of Communication Signals

Science.gov (United States)

Wang, Hui; Li, Jingchao; Guo, Lili; Dou, Zheng; Lin, Yun; Zhou, Ruolin

How to analyze and identify the characteristics of radiation sources and estimate the threat level by means of detecting, intercepting and locating has been the central issue of electronic support in the electronic warfare, and communication signal recognition is one of the key points to solve this issue. Aiming at accurately extracting the individual characteristics of the radiation source for the increasingly complex communication electromagnetic environment, a novel feature extraction algorithm for individual characteristics of the communication radiation source based on the fractal complexity of the signal is proposed. According to the complexity of the received signal and the situation of environmental noise, use the fractal dimension characteristics of different complexity to depict the subtle characteristics of the signal to establish the characteristic database, and then identify different broadcasting station by gray relation theory system. The simulation results demonstrate that the algorithm can achieve recognition rate of 94% even in the environment with SNR of -10dB, and this provides an important theoretical basis for the accurate identification of the subtle features of the signal at low SNR in the field of information confrontation.

A potential neural substrate for processing functional classes of complex acoustic signals.

Directory of Open Access Journals (Sweden)

Isabelle George

Full Text Available Categorization is essential to all cognitive processes, but identifying the neural substrates underlying categorization processes is a real challenge. Among animals that have been shown to be able of categorization, songbirds are particularly interesting because they provide researchers with clear examples of categories of acoustic signals allowing different levels of recognition, and they possess a system of specialized brain structures found only in birds that learn to sing: the song system. Moreover, an avian brain nucleus that is analogous to the mammalian secondary auditory cortex (the caudo-medial nidopallium, or NCM has recently emerged as a plausible site for sensory representation of birdsong, and appears as a well positioned brain region for categorization of songs. Hence, we tested responses in this non-primary, associative area to clear and distinct classes of songs with different functions and social values, and for a possible correspondence between these responses and the functional aspects of songs, in a highly social songbird species: the European starling. Our results clearly show differential neuronal responses to the ethologically defined classes of songs, both in the number of neurons responding, and in the response magnitude of these neurons. Most importantly, these differential responses corresponded to the functional classes of songs, with increasing activation from non-specific to species-specific and from species-specific to individual-specific sounds. These data therefore suggest a potential neural substrate for sorting natural communication signals into categories, and for individual vocal recognition of same-species members. Given the many parallels that exist between birdsong and speech, these results may contribute to a better understanding of the neural bases of speech.

Acoustic logic gates and Boolean operation based on self-collimating acoustic beams

International Nuclear Information System (INIS)

Zhang, Ting; Xu, Jian-yi; Cheng, Ying; Liu, Xiao-jun; Guo, Jian-zhong

2015-01-01

The reveal of self-collimation effect in two-dimensional (2D) photonic or acoustic crystals has opened up possibilities for signal manipulation. In this paper, we have proposed acoustic logic gates based on the linear interference of self-collimated beams in 2D sonic crystals (SCs) with line-defects. The line defects on the diagonal of the 2D square SCs are actually functioning as a 3 dB splitter. By adjusting the phase difference between two input signals, the basic Boolean logic functions such as XOR, OR, AND, and NOT are achieved both theoretically and experimentally. Due to the non-diffracting property of self-collimation beams, more complex Boolean logic and algorithms such as NAND, NOR, and XNOR can be realized by cascading the basic logic gates. The achievement of acoustic logic gates and Boolean operation provides a promising approach for acoustic signal computing and manipulations

Throughput Analysis on 3-Dimensional Underwater Acoustic Network with One-Hop Mobile Relay

Science.gov (United States)

Zhong, Xuefeng; Fan, Jiasheng; Guan, Quansheng; Ji, Fei; Yu, Hua

2018-01-01

Underwater acoustic communication network (UACN) has been considered as an essential infrastructure for ocean exploitation. Performance analysis of UACN is important in underwater acoustic network deployment and management. In this paper, we analyze the network throughput of three-dimensional randomly deployed transmitter–receiver pairs. Due to the long delay of acoustic channels, complicated networking protocols with heavy signaling overhead may not be appropriate. In this paper, we consider only one-hop or two-hop transmission, to save the signaling cost. That is, we assume the transmitter sends the data packet to the receiver by one-hop direct transmission, or by two-hop transmission via mobile relays. We derive the closed-form formulation of packet delivery rate with respect to the transmission delay and the number of transmitter–receiver pairs. The correctness of the derivation results are verified by computer simulations. Our analysis indicates how to obtain a precise tradeoff between the delay constraint and the network capacity. PMID:29337911

Throughput Analysis on 3-Dimensional Underwater Acoustic Network with One-Hop Mobile Relay.

Science.gov (United States)

Zhong, Xuefeng; Chen, Fangjiong; Fan, Jiasheng; Guan, Quansheng; Ji, Fei; Yu, Hua

2018-01-16

Underwater acoustic communication network (UACN) has been considered as an essential infrastructure for ocean exploitation. Performance analysis of UACN is important in underwater acoustic network deployment and management. In this paper, we analyze the network throughput of three-dimensional randomly deployed transmitter-receiver pairs. Due to the long delay of acoustic channels, complicated networking protocols with heavy signaling overhead may not be appropriate. In this paper, we consider only one-hop or two-hop transmission, to save the signaling cost. That is, we assume the transmitter sends the data packet to the receiver by one-hop direct transmission, or by two-hop transmission via mobile relays. We derive the closed-form formulation of packet delivery rate with respect to the transmission delay and the number of transmitter-receiver pairs. The correctness of the derivation results are verified by computer simulations. Our analysis indicates how to obtain a precise tradeoff between the delay constraint and the network capacity.

Hybrid Speaker Recognition Using Universal Acoustic Model

Science.gov (United States)

Nishimura, Jun; Kuroda, Tadahiro

We propose a novel speaker recognition approach using a speaker-independent universal acoustic model (UAM) for sensornet applications. In sensornet applications such as “Business Microscope”, interactions among knowledge workers in an organization can be visualized by sensing face-to-face communication using wearable sensor nodes. In conventional studies, speakers are detected by comparing energy of input speech signals among the nodes. However, there are often synchronization errors among the nodes which degrade the speaker recognition performance. By focusing on property of the speaker's acoustic channel, UAM can provide robustness against the synchronization error. The overall speaker recognition accuracy is improved by combining UAM with the energy-based approach. For 0.1s speech inputs and 4 subjects, speaker recognition accuracy of 94% is achieved at the synchronization error less than 100ms.

Multimodal signal variation in space and time : how important is matching a signal with its signaler?

OpenAIRE

Taylor, Ryan C.; Klein, Barrett; Stein, Joey; Ryan, Michael J.

2011-01-01

Multimodal signals (acoustic+visual) are known to be used by many anuran amphibians during courtship displays. The relative degree to which each signal component influences female mate choice, however, remains poorly understood. In this study we used a robotic frog with an inflating vocal sac and acoustic playbacks to document responses of female túngara frogs to unimodal signal components (acoustic and visual). We then tested female responses to a synchronous multimodal signal. Finally, we t...

Transmission Characteristics of Primate Vocalizations: Implications for Acoustic Analyses

Science.gov (United States)

Maciej, Peter; Fischer, Julia; Hammerschmidt, Kurt

2011-01-01

Acoustic analyses have become a staple method in field studies of animal vocal communication, with nearly all investigations using computer-based approaches to extract specific features from sounds. Various algorithms can be used to extract acoustic variables that may then be related to variables such as individual identity, context or reproductive state. Habitat structure and recording conditions, however, have strong effects on the acoustic structure of sound signals. The purpose of this study was to identify which acoustic parameters reliably describe features of propagated sounds. We conducted broadcast experiments and examined the influence of habitat type, transmission height, and re-recording distance on the validity (deviation from the original sound) and reliability (variation within identical recording conditions) of acoustic features of different primate call types. Validity and reliability varied independently of each other in relation to habitat, transmission height, and re-recording distance, and depended strongly on the call type. The smallest deviations from the original sounds were obtained by a visually-controlled calculation of the fundamental frequency. Start- and end parameters of a sound were most susceptible to degradation in the environment. Because the recording conditions can have appreciable effects on acoustic parameters, it is advisable to validate the extraction method of acoustic variables from recordings over longer distances before using them in acoustic analyses. PMID:21829682

Plant signalling: the opportunities and dangers of chemical communication.

Science.gov (United States)

Adler, Frederick R

2011-04-23

The notion of chemical communication between plants and other organisms has gone from being viewed as a fringe idea to an accepted ecological phenomenon only recently. An Organized Oral Session at the August 2010 Ecological Society of America meeting in Pittsburgh examined the role of plant signalling both within and between plants, with speakers addressing the remarkably wide array of effects that plant signals have on plant physiology, species interactions and entire communities. In addition to the familiar way that plants communicate with mutualists like pollinators and fruit dispersers through both chemical and visual cues, speakers at this session described how plants communicate with themselves, with each other, with herbivores and with predators of those herbivores. These plant signals create a complex odour web superimposed upon the more classical food web itself, with its own dynamics in the face of exotic species and rapid community assembly and disassembly.

Speech Intelligibility Advantages using an Acoustic Beamformer Display

Science.gov (United States)

Begault, Durand R.; Sunder, Kaushik; Godfroy, Martine; Otto, Peter

2015-01-01

A speech intelligibility test conforming to the Modified Rhyme Test of ANSI S3.2 "Method for Measuring the Intelligibility of Speech Over Communication Systems" was conducted using a prototype 12-channel acoustic beamformer system. The target speech material (signal) was identified against speech babble (noise), with calculated signal-noise ratios of 0, 5 and 10 dB. The signal was delivered at a fixed beam orientation of 135 deg (re 90 deg as the frontal direction of the array) and the noise at 135 deg (co-located) and 0 deg (separated). A significant improvement in intelligibility from 57% to 73% was found for spatial separation for the same signal-noise ratio (0 dB). Significant effects for improved intelligibility due to spatial separation were also found for higher signal-noise ratios (5 and 10 dB).

Airborne DoA estimation of gunshot acoustic signals using drones with application to sniper localization systems

Science.gov (United States)

Fernandes, Rigel P.; Ramos, António L. L.; Apolinário, José A.

2017-05-01

Shooter localization systems have been subject of a growing attention lately owing to its wide span of possible applications, e.g., civil protection, law enforcement, and support to soldiers in missions where snipers might pose a serious threat. These devices are based on the processing of electromagnetic or acoustic signatures associated with the firing of a gun. This work is concerned with the latter, where the shooter's position can be obtained based on the estimation of the direction-of-arrival (DoA) of the acoustic components of a gunshot signal (muzzle blast and shock wave). A major limitation of current commercially available acoustic sniper localization systems is the impossibility of finding the shooter's position when one of these acoustic signatures is not detected. This is very likely to occur in real-life situations, especially when the microphones are not in the field of view of the shockwave or when the presence of obstacles like buildings can prevent a direct-path to sensors. This work addresses the problem of DoA estimation of the muzzle blast using a planar array of sensors deployed in a drone. Results supported by actual gunshot data from a realistic setup are very promising and pave the way for the development of enhanced sniper localization systems featuring two main advantages over stationary ones: (1) wider surveillance area; and (2) increased likelihood of a direct-path detection of at least one of the gunshot signals, thereby adding robustness and reliability to the system.

Flash signal evolution in Photinus fireflies: character displacement and signal exploitation in a visual communication system.

Science.gov (United States)

Stanger-Hall, Kathrin F; Lloyd, James E

2015-03-01

Animal communication is an intriguing topic in evolutionary biology. In this comprehensive study of visual signal evolution, we used a phylogenetic approach to study the evolution of the flash communication system of North American fireflies. The North American firefly genus Photinus contains 35 described species with simple ON-OFF visual signals, and information on habitat types, sympatric congeners, and predators. This makes them an ideal study system to test hypotheses on the evolution of male and female visual signal traits. Our analysis of 34 Photinus species suggests two temporal pattern generators: one for flash duration and one for flash intervals. Reproductive character displacement was a main factor for signal divergence in male flash duration among sympatric Photinus species. Male flash pattern intervals (i.e., the duration of the dark periods between signals) were positively correlated with the number of sympatric Photuris fireflies, which include predators of Photinus. Females of different Photinus species differ in their response preferences to male traits. As in other communication systems, firefly male sexual signals seem to be a compromise between optimizing mating success (sexual selection) and minimizing predation risk (natural selection). An integrative model for Photinus signal evolution is proposed. © 2015 The Author(s).

Perceived Synchrony of Frog Multimodal Signal Components Is Influenced by Content and Order.

Science.gov (United States)

Taylor, Ryan C; Page, Rachel A; Klein, Barrett A; Ryan, Michael J; Hunter, Kimberly L

2017-10-01

Multimodal signaling is common in communication systems. Depending on the species, individual signal components may be produced synchronously as a result of physiological constraint (fixed) or each component may be produced independently (fluid) in time. For animals that rely on fixed signals, a basic prediction is that asynchrony between the components should degrade the perception of signal salience, reducing receiver response. Male túngara frogs, Physalaemus pustulosus, produce a fixed multisensory courtship signal by vocalizing with two call components (whines and chucks) and inflating a vocal sac (visual component). Using a robotic frog, we tested female responses to variation in the temporal arrangement between acoustic and visual components. When the visual component lagged a complex call (whine + chuck), females largely rejected this asynchronous multisensory signal in favor of the complex call absent the visual cue. When the chuck component was removed from one call, but the robofrog inflation lagged the complex call, females responded strongly to the asynchronous multimodal signal. When the chuck component was removed from both calls, females reversed preference and responded positively to the asynchronous multisensory signal. When the visual component preceded the call, females responded as often to the multimodal signal as to the call alone. These data show that asynchrony of a normally fixed signal does reduce receiver responsiveness. The magnitude and overall response, however, depend on specific temporal interactions between the acoustic and visual components. The sensitivity of túngara frogs to lagging visual cues, but not leading ones, and the influence of acoustic signal content on the perception of visual asynchrony is similar to those reported in human psychophysics literature. Virtually all acoustically communicating animals must conduct auditory scene analyses and identify the source of signals. Our data suggest that some basic

Human sensorimotor communication: a theory of signaling in online social interactions.

Science.gov (United States)

Pezzulo, Giovanni; Donnarumma, Francesco; Dindo, Haris

2013-01-01

Although the importance of communication is recognized in several disciplines, it is rarely studied in the context of online social interactions and joint actions. During online joint actions, language and gesture are often insufficient and humans typically use non-verbal, sensorimotor forms of communication to send coordination signals. For example, when playing volleyball, an athlete can exaggerate her movements to signal her intentions to her teammates (say, a pass to the right) or to feint an adversary. Similarly, a person who is transporting a table together with a co-actor can push the table in a certain direction to signal where and when he intends to place it. Other examples of "signaling" are over-articulating in noisy environments and over-emphasizing vowels in child-directed speech. In all these examples, humans intentionally modify their action kinematics to make their goals easier to disambiguate. At the moment no formal theory exists of these forms of sensorimotor communication and signaling. We present one such theory that describes signaling as a combination of a pragmatic and a communicative action, and explains how it simplifies coordination in online social interactions. We cast signaling within a "joint action optimization" framework in which co-actors optimize the success of their interaction and joint goals rather than only their part of the joint action. The decision of whether and how much to signal requires solving a trade-off between the costs of modifying one's behavior and the benefits in terms of interaction success. Signaling is thus an intentional strategy that supports social interactions; it acts in concert with automatic mechanisms of resonance, prediction, and imitation, especially when the context makes actions and intentions ambiguous and difficult to read. Our theory suggests that communication dynamics should be studied within theories of coordination and interaction rather than only in terms of the maximization of information

Human sensorimotor communication: a theory of signaling in online social interactions.

Directory of Open Access Journals (Sweden)

Giovanni Pezzulo

Full Text Available Although the importance of communication is recognized in several disciplines, it is rarely studied in the context of online social interactions and joint actions. During online joint actions, language and gesture are often insufficient and humans typically use non-verbal, sensorimotor forms of communication to send coordination signals. For example, when playing volleyball, an athlete can exaggerate her movements to signal her intentions to her teammates (say, a pass to the right or to feint an adversary. Similarly, a person who is transporting a table together with a co-actor can push the table in a certain direction to signal where and when he intends to place it. Other examples of "signaling" are over-articulating in noisy environments and over-emphasizing vowels in child-directed speech. In all these examples, humans intentionally modify their action kinematics to make their goals easier to disambiguate. At the moment no formal theory exists of these forms of sensorimotor communication and signaling. We present one such theory that describes signaling as a combination of a pragmatic and a communicative action, and explains how it simplifies coordination in online social interactions. We cast signaling within a "joint action optimization" framework in which co-actors optimize the success of their interaction and joint goals rather than only their part of the joint action. The decision of whether and how much to signal requires solving a trade-off between the costs of modifying one's behavior and the benefits in terms of interaction success. Signaling is thus an intentional strategy that supports social interactions; it acts in concert with automatic mechanisms of resonance, prediction, and imitation, especially when the context makes actions and intentions ambiguous and difficult to read. Our theory suggests that communication dynamics should be studied within theories of coordination and interaction rather than only in terms of the

Canada Basin Acoustic Propagation Experiment (CANAPE)

Science.gov (United States)

2015-09-30

acoustic communications, acoustic navigation, or acoustic remote sensing of the ocean interior . RELATED PROJECTS The 2015 CANAPE pilot study was a...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Canada Basin Acoustic Propagation Experiment (CANAPE...ocean structure. Changes in sea ice and the water column affect both acoustic propagation and ambient noise. This implies that what was learned

Transmission acoustic microscopy investigation

Science.gov (United States)

Maev, Roman; Kolosov, Oleg; Levin, Vadim; Lobkis, Oleg

The nature of acoustic contrast, i.e. the connection of the amplitude and phase of the output signal of the acoustic microscope with the local values of the acoustic parameters of the sample (density, elasticity, viscosity) is a central problem of acoustic microscopy. A considerable number of studies have been devoted to the formation of the output signal of the reflection scanning acoustic microscope. For the transmission acoustic microscope (TAM) this problem has remained almost unstudied. Experimental investigation of the confocal system of the TAM was carried out on an independently manufactured laboratory mockup of the TAM with the working frequency of the 420 MHz. Acoustic lenses with the radius of curvature of about 500 microns and aperture angle of 45 deg were polished out in the end faces of two cylindrical sound conductors made from Al2O3 single crystals with an axis parallel to the axis C of the crystal (the length of the sound conductor is 20 mm; diameter, 6 mm). At the end faces of the sound conductor, opposite to the lenses, CdS transducers with a diameter of 2 mm were disposed. The electric channel of the TAM provided a possibility for registering the amplitude of the microscope output signal in the case of the dynamic range of the 50 dB.

Transmission experiment by the simulated LMFBR model and propagation analysis of acoustic signals

International Nuclear Information System (INIS)

Kobayashi, Kenji; Yasuda, Tsutomu; Araki, Hitoshi.

1981-01-01

Acoustic transducers to detect a boiling of sodium may be installed in the upper structure and at the upper position of reactor vessel wall under constricted conditions. A set of the experiments of transmission of acoustic vibration to various points of the vessel was performed utilizing the half scale-hydraulic flow test facility simulating reactor vessel over the frequency range 20 kHz -- 100 kHz. Acoustic signals from an installed sound source in the core were measured at each point by both hydrophones in the vessel and vibration pickups on the vessel wall. In these experiments transmission of signals to each point of detectors were clearly observed to background noise level. These data have been summarized in terms of the transmission loss and furthermore are compared with background noise level of flow to estimate the feasibility of detection of sodium boiling sound. The ratio of signal to noise was obtained to be about 13 dB by hydrophone in the upper structure, 8 dB by accelerometer and 16 dB by AE-sensor at the upper position on the vessel in experiments used the simulation model. Sound waves emanated due to sodium boiling also propagate along the wall of the vessel may be predicted theoretically. The result of analysis suggests a capability of detection at the upper position of the reactor vessel wall. Leaky Lamb waves of the first symmetric (L 1 ) and of the antisymmetric (F 1 ) mode and shear horizontal wave (SH) have been derived in light of the attenuation due to coupling to liquid sodium as the traveling modes over the frequency range 10 kHz -- 100 kHz up to 50 mm in thickness of the vessel wall. Leaky Lamb wave (L 1 ) and (SH) mode have been proposed theoretically on the some assumption to be most available to detect the boiling sound of sodium propagating along the vessel wall. (author)

Signals and cues in the evolution of plant-microbe communication.

Science.gov (United States)

Padje, Anouk Van't; Whiteside, Matthew D; Kiers, E Toby

2016-08-01

Communication has played a key role in organismal evolution. If sender and receiver have a shared interest in propagating reliable information, such as when they are kin relatives, then effective communication can bring large fitness benefits. However, interspecific communication (among different species) is more prone to dishonesty. Over the last decade, plants and their microbial root symbionts have become a model system for studying interspecific molecular crosstalk. However, less is known about the evolutionary stability of plant-microbe communication. What prevents partners from hijacking or manipulating information to their own benefit? Here, we focus on communication between arbuscular mycorrhizal fungi and their host plants. We ask how partners use directed signals to convey specific information, and highlight research on the problem of dishonest signaling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Patterns of Song across Natural and Anthropogenic Soundscapes Suggest That White-Crowned Sparrows Minimize Acoustic Masking and Maximize Signal Content.

Directory of Open Access Journals (Sweden)

Elizabeth P Derryberry

Full Text Available Soundscapes pose both evolutionarily recent and long-standing sources of selection on acoustic communication. We currently know more about the impact of evolutionarily recent human-generated noise on communication than we do about how natural sounds such as pounding surf have shaped communication signals over evolutionary time. Based on signal detection theory, we hypothesized that acoustic phenotypes will vary with both anthropogenic and natural background noise levels and that similar mechanisms of cultural evolution and/or behavioral flexibility may underlie this variation. We studied song characteristics of white-crowned sparrows (Zonotrichia leucophrys nuttalli across a noise gradient that includes both anthropogenic and natural sources of noise in San Francisco and Marin counties, California, USA. Both anthropogenic and natural soundscapes contain high amplitude low frequency noise (traffic or surf, respectively, so we predicted that birds would produce songs with higher minimum frequencies in areas with higher amplitude background noise to avoid auditory masking. We also anticipated that song minimum frequencies would be higher than the projected lower frequency limit of hearing based on site-specific masking profiles. Background noise was a strong predictor of song minimum frequency, both within a local noise gradient of three urban sites with the same song dialect and cultural evolutionary history, and across the regional noise gradient, which encompasses 11 urban and rural sites, several dialects, and several anthropogenic and natural sources of noise. Among rural sites alone, background noise tended to predict song minimum frequency, indicating that urban sites were not solely responsible for driving the regional pattern. These findings support the hypothesis that songs vary with local and regional soundscapes regardless of the source of noise. Song minimum frequency from five core study sites was also higher than the lower frequency

Patterns of Song across Natural and Anthropogenic Soundscapes Suggest That White-Crowned Sparrows Minimize Acoustic Masking and Maximize Signal Content.

Science.gov (United States)

Derryberry, Elizabeth P; Danner, Raymond M; Danner, Julie E; Derryberry, Graham E; Phillips, Jennifer N; Lipshutz, Sara E; Gentry, Katherine; Luther, David A

2016-01-01

Soundscapes pose both evolutionarily recent and long-standing sources of selection on acoustic communication. We currently know more about the impact of evolutionarily recent human-generated noise on communication than we do about how natural sounds such as pounding surf have shaped communication signals over evolutionary time. Based on signal detection theory, we hypothesized that acoustic phenotypes will vary with both anthropogenic and natural background noise levels and that similar mechanisms of cultural evolution and/or behavioral flexibility may underlie this variation. We studied song characteristics of white-crowned sparrows (Zonotrichia leucophrys nuttalli) across a noise gradient that includes both anthropogenic and natural sources of noise in San Francisco and Marin counties, California, USA. Both anthropogenic and natural soundscapes contain high amplitude low frequency noise (traffic or surf, respectively), so we predicted that birds would produce songs with higher minimum frequencies in areas with higher amplitude background noise to avoid auditory masking. We also anticipated that song minimum frequencies would be higher than the projected lower frequency limit of hearing based on site-specific masking profiles. Background noise was a strong predictor of song minimum frequency, both within a local noise gradient of three urban sites with the same song dialect and cultural evolutionary history, and across the regional noise gradient, which encompasses 11 urban and rural sites, several dialects, and several anthropogenic and natural sources of noise. Among rural sites alone, background noise tended to predict song minimum frequency, indicating that urban sites were not solely responsible for driving the regional pattern. These findings support the hypothesis that songs vary with local and regional soundscapes regardless of the source of noise. Song minimum frequency from five core study sites was also higher than the lower frequency limit of hearing

Phase synchronization of instrumental music signals

Science.gov (United States)

Mukherjee, Sayan; Palit, Sanjay Kumar; Banerjee, Santo; Ariffin, M. R. K.; Bhattacharya, D. K.

2014-06-01

Signal analysis is one of the finest scientific techniques in communication theory. Some quantitative and qualitative measures describe the pattern of a music signal, vary from one to another. Same musical recital, when played by different instrumentalists, generates different types of music patterns. The reason behind various patterns is the psycho-acoustic measures - Dynamics, Timber, Tonality and Rhythm, varies in each time. However, the psycho-acoustic study of the music signals does not reveal any idea about the similarity between the signals. For such cases, study of synchronization of long-term nonlinear dynamics may provide effective results. In this context, phase synchronization (PS) is one of the measures to show synchronization between two non-identical signals. In fact, it is very critical to investigate any other kind of synchronization for experimental condition, because those are completely non identical signals. Also, there exists equivalence between the phases and the distances of the diagonal line in Recurrence plot (RP) of the signals, which is quantifiable by the recurrence quantification measure τ-recurrence rate. This paper considers two nonlinear music signals based on same raga played by two eminent sitar instrumentalists as two non-identical sources. The psycho-acoustic study shows how the Dynamics, Timber, Tonality and Rhythm vary for the two music signals. Then, long term analysis in the form of phase space reconstruction is performed, which reveals the chaotic phase spaces for both the signals. From the RP of both the phase spaces, τ-recurrence rate is calculated. Finally by the correlation of normalized tau-recurrence rate of their 3D phase spaces and the PS of the two music signals has been established. The numerical results well support the analysis.

Evolution of Signaling in a Multi-Robot System: Categorization and Communication

Science.gov (United States)

Ampatzis, Christos; Tuci, Elio; Trianni, Vito; Dorigo, Marco

We use Evolutionary Robotics to design robot controllers in which decision-making mechanisms to switch from solitary to social behavior are integrated with the mechanisms that underpin the sensory-motor repertoire of the robots. In particular, we study the evolution of behavioral and communicative skills in a categorization task. The individual decision-making structures are based on the integration over time of sensory information. The mechanisms for switching from solitary to social behavior and the ways in which the robots can affect each other's behavior are not predetermined by the experimenter, but are aspects of our model designed by artificial evolution. Our results show that evolved robots manage to cooperate and collectively discriminate between different environments by developing a simple communication protocol based on sound signaling. Communication emerges in the absence of explicit selective pressure coded in the fitness function. The evolution of communication is neither trivial nor obvious; for a meaningful signaling system to evolve, evolution must produce both appropriate signals and appropriate reactions to signals. The use of communication proves to be adaptive for the group, even if, in principle, non-cooperating robots can be equally successful with cooperating robots.

Evolutionary divergence in sexual signals: Insights from within and among barn swallow populations

Science.gov (United States)

Wilkins, Matthew Reed

A wealth of studies across diverse animal groups indicate the importance of sexual selection in shaping phenotypes within and across breeding populations. In recent decades, much research has focused on how divergent sexual selection pressures among populations may lead to speciation. For my first dissertation chapter, I performed a literature review on the causes and consequences of evolutionary divergence in acoustic signals and developed the acoustic window conceptual framework for understanding the contributions of selection, genetic drift, and evolutionary constraint to signal divergence. Further, I found that sexual selection explains acoustic differences between recently diverged populations of the best-studied taxa. However, the relative contributions of ecological selection, sexual selection, and drift to acoustic divergence have not typically been considered within the same study systems. The remainder of my dissertation used the Northern Hemisphere-distributed barn swallow ( Hirundo rustica) species complex as a model system to study sender-receiver dynamics, intra- and intersexual selection pressures, and visual and acoustic signal interactions at the local scale, and signal divergence across populations at the global scale. From song recordings taken across 19 sampling sites, spanning five of six described subspecies, I demonstrated considerable conservation in song structure. However, temporal traits were highly divergent across subspecies, and in particular, the speed of the terminal trill of songs. In a detailed study of the multimodal communication system of the barn swallow (including visual and acoustic traits), I demonstrated that males and females use different types of signals to mediate competition and mate choice. One of the only exceptions to this rule was trill rate, which was also implicated in song divergence across populations. In order to test the function of trill rate in communication, I performed a two-year playback study within the

A Review on Human Body Communication: Signal Propagation Model, Communication Performance, and Experimental Issues

Directory of Open Access Journals (Sweden)

Jian Feng Zhao

2017-01-01

Full Text Available Human body communication (HBC, which uses the human body tissue as the transmission medium to transmit health informatics, serves as a promising physical layer solution for the body area network (BAN. The human centric nature of HBC offers an innovative method to transfer the healthcare data, whose transmission requires low interference and reliable data link. Therefore, the deployment of HBC system obtaining good communication performance is required. In this regard, a tutorial review on the important issues related to HBC data transmission such as signal propagation model, channel characteristics, communication performance, and experimental considerations is conducted. In this work, the development of HBC and its first attempts are firstly reviewed. Then a survey on the signal propagation models is introduced. Based on these models, the channel characteristics are summarized; the communication performance and selection of transmission parameters are also investigated. Moreover, the experimental issues, such as electrodes and grounding strategies, are also discussed. Finally, the recommended future studies are provided.

Acoustic Leak Detection Testing Using KAERI Sodium-Water Reaction Signals for a SFR Steam Generator

International Nuclear Information System (INIS)

Kim, Tae-Joon; Jeong, Ji-Young; Kim, Jong-Man; Kim, Byung-Ho; Hahn, Do-Hee; Yugay, Valeriy S.

2009-01-01

The results of an experimental study of water in a sodium leak noise spectrum formation at 0.004-0.54 g/sec, various rates of water into a sodium leak, smaller than 1.0 g/sec, are presented. We focused on studying a micro leak detection with an increasing rate of water into sodium. On the basis of the experimental leak noise data manufactured in KAERI the simple dependency of an acoustic signal level from the rate of a micro and small leak at different frequency bands is presented to understand the principal analysis for the development of an acoustic leak detection methodology used in a K- 600 steam generator

Acoustics and sociolinguistics: Patterns of communication in hearing impairing classrooms

Science.gov (United States)

McKellin, William; Shahin, Kimary; Jamieson, Janet; Hodgson, Murray; Pichora-Fuller, Kathleen

2005-04-01

In elementary school classes, noise during student led activities is often taken as evidence of successful interaction and learning. In this complex social environment of elementary school classrooms, acquisition of complex language and social skills-the focus of activities in early education-is expected to take place in hearing-hostile environments. Communication and language processing in these contexts requires interactive strategies, discourse forms, and syntactic structures different from the educationally desired forms used in acoustically advantageous environments. Recordings were made of the interaction of groups of students in grades 1-3, 5, and 7 during collaborative group work in their regular classrooms. Each student wore microphones at the ear level and head-mounted video cameras. Each group as a whole was also audio- and videotaped and noise level readings were recorded. Analysis of the acoustical and phonological properties of language heard by each student has demonstrated that the language variety used in these noisy and reverberant settings is similar to that of individuals with hearing impairments. This paper reports similarities between the syntactic structures and pragmatic strategies used by hearing impaired children and normally hearing children in noisy contexts. [Work supported by Peter Wall Institute for Advanced Studies, University of British Columbia.

Acoustical conditions for speech communication in active elementary school classrooms

Science.gov (United States)

Sato, Hiroshi; Bradley, John

2005-04-01

Detailed acoustical measurements were made in 34 active elementary school classrooms with typical rectangular room shape in schools near Ottawa, Canada. There was an average of 21 students in classrooms. The measurements were made to obtain accurate indications of the acoustical quality of conditions for speech communication during actual teaching activities. Mean speech and noise levels were determined from the distribution of recorded sound levels and the average speech-to-noise ratio was 11 dBA. Measured mid-frequency reverberation times (RT) during the same occupied conditions varied from 0.3 to 0.6 s, and were a little less than for the unoccupied rooms. RT values were not related to noise levels. Octave band speech and noise levels, useful-to-detrimental ratios, and Speech Transmission Index values were also determined. Key results included: (1) The average vocal effort of teachers corresponded to louder than Pearsons Raised voice level; (2) teachers increase their voice level to overcome ambient noise; (3) effective speech levels can be enhanced by up to 5 dB by early reflection energy; and (4) student activity is seen to be the dominant noise source, increasing average noise levels by up to 10 dBA during teaching activities. [Work supported by CLLRnet.

Analysis of acoustic cardiac signals for heart rate variability and murmur detection using nonnegative matrix factorization-based hierarchical decomposition

DEFF Research Database (Denmark)

Shah, Ghafoor; Koch, Peter; Papadias, Constantinos B.

2014-01-01

The detection of heart rate variability (HRV) via cardiac auscultation examination can be a useful and inexpensive tool which, however, is challenging in the presence of pathological signals and murmurs. The aim of this research is to analyze acoustic cardiac signals for HRV and murmur detection...

PORTABLE ACOUSTIC MONITORING PACKAGE (PAMP)

Energy Technology Data Exchange (ETDEWEB)

John l. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Deepak Mehra

2003-07-01

The 1st generation acoustic monitoring package was designed to detect and analyze weak acoustic signals inside natural gas transmission lines. Besides a microphone it housed a three-inch diameter aerodynamic acoustic signal amplifier to maximize sensitivity to leak induced {Delta}p type signals. The theory and test results of this aerodynamic signal amplifier was described in the master's degree thesis of our Research Assistant Deepak Mehra who is about to graduate. To house such a large three-inch diameter sensor required the use of a steel 300-psi rated 4 inch weld neck flange, which itself weighed already 29 pounds. The completed 1st generation Acoustic Monitoring Package weighed almost 100 pounds. This was too cumbersome to mount in the field, on an access port at a pipeline shut-off valve. Therefore a 2nd generation and truly Portable Acoustic Monitor was built. It incorporated a fully self-contained {Delta}p type signal sensor, rated for line pressures up to 1000 psi with a base weight of only 6 pounds. This is the Rosemont Inc. Model 3051CD-Range 0, software driven sensor, which is believed to have industries best total performance. Its most sensitive unit was purchased with a {Delta}p range from 0 to 3 inch water. This resulted in the herein described 2nd generation: Portable Acoustic Monitoring Package (PAMP) for pipelines up to 1000 psi. Its 32-pound total weight includes an 18-volt battery. Together with a 3 pound laptop with its 4-channel data acquisition card, completes the equipment needed for field acoustic monitoring of natural gas transmission pipelines.

Numerical analysis on acoustic impulse response for watermelon

International Nuclear Information System (INIS)

Kim, Yong Sul; Yang, Dong Hoon; Choi, Young Jae; Bae, Tas Joo; So, Chul Ho; Lee, Yun Ho

2002-01-01

In this study, we conducted both analysis on impact pulse signal and acoustic impulse response method using numerical analysistic finite element method. Considering its velocity, density, Young's Modulus, and Poisson's Ratio, we extracted featured parameters and compared both results of analysis on impact pulse signal and numerical analysis on acoustic impulse response then we found the feature of generated acoustic sound signal by way of numerical analysis varying featured parameters and consequently intended to extract feature indices influenced on its internal maturity through analysis of acoustic impulse response. As we analyzed impact pulse signal and extracted featured parameters concerned with evaluation of its ripeness, we found the plausibility of progress on nondestructive evaluation of ripeness and adoption of numerical analysis on acoustic impulse response.

Neurochemical Architecture of the Central Complex Related to Its Function in the Control of Grasshopper Acoustic Communication

Science.gov (United States)

Kunst, Michael; Pförtner, Ramona; Aschenbrenner, Katja; Heinrich, Ralf

2011-01-01

The central complex selects and coordinates the species- and situation-specific song production in acoustically communicating grasshoppers. Control of sound production is mediated by several neurotransmitters and modulators, their receptors and intracellular signaling pathways. It has previously been shown that muscarinic cholinergic excitation in the central complex promotes sound production whereas both GABA and nitric oxide/cyclic GMP signaling suppress its performance. The present immunocytochemical and pharmacological study investigates the question whether GABA and nitric oxide mediate inhibition of sound production independently. Muscarinic ACh receptors are expressed by columnar output neurons of the central complex that innervate the lower division of the central body and terminate in the lateral accessory lobes. GABAergic tangential neurons that innervate the lower division of the central body arborize in close proximity of columnar neurons and thus may directly inhibit these central complex output neurons. A subset of these GABAergic tangential neurons accumulates cyclic GMP following the release of nitric oxide from neurites in the upper division of the central body. While sound production stimulated by muscarine injection into the central complex is suppressed by co-application of sodium nitroprusside, picrotoxin-stimulated singing was not affected by co-application of this nitric oxide donor, indicating that nitric oxide mediated inhibition requires functional GABA signaling. Hence, grasshopper sound production is controlled by processing of information in the lower division of the central body which is subject to modulation by nitric oxide released from neurons in the upper division. PMID:21980504

A hardware model of the auditory periphery to transduce acoustic signals into neural activity

Directory of Open Access Journals (Sweden)

Takashi eTateno

2013-11-01

Full Text Available To improve the performance of cochlear implants, we have integrated a microdevice into a model of the auditory periphery with the goal of creating a microprocessor. We constructed an artificial peripheral auditory system using a hybrid model in which polyvinylidene difluoride was used as a piezoelectric sensor to convert mechanical stimuli into electric signals. To produce frequency selectivity, the slit on a stainless steel base plate was designed such that the local resonance frequency of the membrane over the slit reflected the transfer function. In the acoustic sensor, electric signals were generated based on the piezoelectric effect from local stress in the membrane. The electrodes on the resonating plate produced relatively large electric output signals. The signals were fed into a computer model that mimicked some functions of inner hair cells, inner hair cell–auditory nerve synapses, and auditory nerve fibers. In general, the responses of the model to pure-tone burst and complex stimuli accurately represented the discharge rates of high-spontaneous-rate auditory nerve fibers across a range of frequencies greater than 1 kHz and middle to high sound pressure levels. Thus, the model provides a tool to understand information processing in the peripheral auditory system and a basic design for connecting artificial acoustic sensors to the peripheral auditory nervous system. Finally, we discuss the need for stimulus control with an appropriate model of the auditory periphery based on auditory brainstem responses that were electrically evoked by different temporal pulse patterns with the same pulse number.

Sodium boiling detection in LMFBRs by acoustic-neutronic cross correlation

International Nuclear Information System (INIS)

Wright, S.A.

1977-01-01

The acoustic and neutronic noise signals caused by boiling are the signals primarily considered likely to detect sodium boiling in an LMFBR. Unfortunately, these signals may have serious signal-to-noise problems due to strong background noise sources. Neutronic-acoustic cross correlation techniques are expected to provide a means of improving the signal-to-noise ratio. This technique can improve the signal-to-noise ratio because the neutronic and acoustic signals due to boiling are highly correlated near the bubble repetition frequency, while the background noise sources are expected to be uncorrelated (or at most weakly correlated). An experiment was designed to show that the neutronic and acoustic noise signals are indeed highly correlated. The experiment consisted of simulating the void and pressure effects of local sodium boiling in the core of a zero-power reactor (ARK). The analysis showed that the neutronic and acoustic noise signals caused by boiling are almost perfectly correlated in a wide frequency band about the bubble repetition frequency. The results of the experiments were generalized to full-scale reactors to compare the inherent effectiveness of the methods which use the neutronic or acoustic signals alone with a hybrid method, which cross correlates the neutronic and acoustic signals. It was concluded that over a zone of the reactor where the void coefficient is sufficiently large (approximately 85 percent the core volume), the cross correlation method can provide a more rapid detection system for a given signal-to-noise ratio. However, where the void coefficient is small, one must probably rely on the acoustic method alone

Regulation of cellular communication by signaling microdomains in the blood vessel wall.

Science.gov (United States)

Billaud, Marie; Lohman, Alexander W; Johnstone, Scott R; Biwer, Lauren A; Mutchler, Stephanie; Isakson, Brant E

2014-01-01

It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function.

Regulation of Cellular Communication by Signaling Microdomains in the Blood Vessel Wall

Science.gov (United States)

Billaud, Marie; Lohman, Alexander W.; Johnstone, Scott R.; Biwer, Lauren A.; Mutchler, Stephanie; Isakson, Brant E.

2014-01-01

It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function. PMID:24671377

Numerical analysis on acoustic impulse response for watermelon

Energy Technology Data Exchange (ETDEWEB)

Kim, Yong Sul; Yang, Dong Hoon; Choi, Young Jae; Bae, Tas Joo; So, Chul Ho [Dongshin University, Naju (Korea, Republic of); Lee, Yun Ho [Korea Inspection and Engineering CO.,LTD., Seoul (Korea, Republic of)

2002-11-15

In this study, we conducted both analysis on impact pulse signal and acoustic impulse response method using numerical analysistic finite element method. Considering its velocity, density, Young's Modulus, and Poisson's Ratio, we extracted featured parameters and compared both results of analysis on impact pulse signal and numerical analysis on acoustic impulse response then we found the feature of generated acoustic sound signal by way of numerical analysis varying featured parameters and consequently intended to extract feature indices influenced on its internal maturity through analysis of acoustic impulse response. As we analyzed impact pulse signal and extracted featured parameters concerned with evaluation of its ripeness, we found the plausibility of progress on nondestructive evaluation of ripeness and adoption of numerical analysis on acoustic impulse response.

Communication and cooperation in underwater acoustic networks

Science.gov (United States)

Yerramalli, Srinivas

In this thesis, we present a study of several problems related to underwater point to point communications and network formation. We explore techniques to improve the achievable data rate on a point to point link using better physical layer techniques and then study sensor cooperation which improves the throughput and reliability in an underwater network. Robust point-to-point communications in underwater networks has become increasingly critical in several military and civilian applications related to underwater communications. We present several physical layer signaling and detection techniques tailored to the underwater channel model to improve the reliability of data detection. First, a simplified underwater channel model in which the time scale distortion on each path is assumed to be the same (single scale channel model in contrast to a more general multi scale model). A novel technique, which exploits the nature of OFDM signaling and the time scale distortion, called Partial FFT Demodulation is derived. It is observed that this new technique has some unique interference suppression properties and performs better than traditional equalizers in several scenarios of interest. Next, we consider the multi scale model for the underwater channel and assume that single scale processing is performed at the receiver. We then derive optimized front end pre-processing techniques to reduce the interference caused during single scale processing of signals transmitted on a multi-scale channel. We then propose an improvised channel estimation technique using dictionary optimization methods for compressive sensing and show that significant performance gains can be obtained using this technique. In the next part of this thesis, we consider the problem of sensor node cooperation among rational nodes whose objective is to improve their individual data rates. We first consider the problem of transmitter cooperation in a multiple access channel and investigate the stability of

Digital signal processing for wireless communication using Matlab

CERN Document Server

Gopi, E S

2016-01-01

This book examines signal processing techniques used in wireless communication illustrated by using the Matlab program. The author discusses these techniques as they relate to Doppler spread; delay spread; Rayleigh and Rician channel modeling; rake receiver; diversity techniques; MIMO and OFDM -based transmission techniques; and array signal processing. Related topics such as detection theory, link budget, multiple access techniques, and spread spectrum are also covered.   ·         Illustrates signal processing techniques involved in wireless communication using Matlab ·         Discusses multiple access techniques such as Frequency division multiple access, Time division multiple access, and Code division multiple access ·         Covers band pass modulation techniques such as Binary phase shift keying, Differential phase shift keying, Quadrature phase shift keying, Binary frequency shift keying, Minimum shift keying, and Gaussian minimum shift keying.

Acoustic emission technique and its applications

International Nuclear Information System (INIS)

Sato, Ichiya; Sasaki, Soji

1976-01-01

Acoustic emission technique is described. The characteristics of acoustic emission signal, measurement techniques, and its application are explained. The acoustic signals are grouped into continuous and burst types. The continuous signal is due to plastic deformation, and the burst type is due to the generation and growth of cracks. The latter can be used for the identification of the position of cracks. The frequency of the acoustic emission is in the range from several tens of KHz to two MHz. Piezoelectric ceramics are used as the oscillators of sensors. The dynamic behavior of acoustic emission can be observed with a two-channel acoustic emission measuring apparatus. Multi-channel method was developed at Hitachi, Ltd., and is used for large structures. General computer identification method and simple zone identification method are explained. Noise elimination is important for the measurement, and the methods were studied. Examples of application are the observation of acoustic emission in the plastic deformation of steel, the tensile test of large welded material with natural defects, and others. The method will be used for the diagnosis and observation of large structures, the test and quality control of products. (Kato, T.)

Carrier frequency offset estimation for an acoustic-electric channel using 16 QAM modulation

Science.gov (United States)

Cunningham, Michael T.; Anderson, Leonard A.; Wilt, Kyle R.; Chakraborty, Soumya; Saulnier, Gary J.; Scarton, Henry A.

2016-05-01

Acoustic-electric channels can be used to send data through metallic barriers, enabling communications where electromagnetic signals are ineffective. This paper considers an acoustic-electric channel that is formed by mounting piezoelectric transducers on metallic barriers that are separated by a thin water layer. The transducers are coupled to the barriers using epoxy and the barriers are positioned to axially-align the PZTs, maximizing energy transfer efficiency. The electrical signals are converted by the transmitting transducers into acoustic waves, which propagate through the elastic walls and water medium to the receiving transducers. The reverberation of the acoustic signals in these channels can produce multipath distortion with a significant delay spread that introduces inter-symbol interference (ISI) into the received signal. While the multipath effects can be severe, the channel does not change rapidly which makes equalization easier. Here we implement a 16-QAM system on this channel, including a method for obtaining accurate carrier frequency offset (CFO) estimates in the presence of the quasi-static multipath propagation. A raised-power approach is considered but found to suffer from excessive data noise resulting from the ISI. An alternative approach that utilizes a pilot tone burst at the start of a data packet is used for CFO estimation and found to be effective. The autocorrelation method is used to estimate the frequency of the received burst. A real-time prototype of the 16 QAM system that uses a Texas Instruments MSP430 microcontroller-based transmitter and a personal computer-based receiver is presented along with performance results.

Adaptive Equalizer Based on Second-Order Cone Programming in Underwater Acoustic Communication

Directory of Open Access Journals (Sweden)

Yang CHEN

2014-01-01

Full Text Available An improved adaptive equalizer based on the principle of minimum mean square error (MMSE is proposed. This optimization problem which is shown to be convex, is transformed to second-order cone (SOC and solved using the interior point method instead of conventional iterative methods such as least mean squares (LMS or recursive least squares (RLS. To validate its performance a single-carrier system for underwater acoustic communication with digital phase-locked loop and the adaptive fractional spaced equalizers was designed and a lake trial was carried out. According to the results, comparing with traditional equalizers based on LMS and RLS algorithms, the equalizer proposed needs no iterative process and gets rid of the contradiction between convergent rate and precision. Therefore it overcomes the difficulty of parameters setting. Furthermore, the algorithm needs much less training codes to achieve the same equalization performance and improves the communication efficiency.

Explaining evolution of plant communication by airborne signals.

Science.gov (United States)

Heil, Martin; Karban, Richard

2010-03-01

In spite of initial doubts about the reality of 'talking trees', plant resistance expression mediated by volatile compounds that come from neighboring plants is now well described. Airborne signals usually improve the resistance of the receiver, but without obvious benefits for the emitter, thus making the evolutionary explanation of this phenomenon problematic. Here, we discuss four possible non-exclusive explanations involving the role of volatiles: in direct defense, as within-plant signals, as traits that synergistically interact with other defenses, and as cues among kin. Unfortunately, there is a lack of knowledge on the fitness consequences of plant communication for both emitter and receiver. This information is crucial to understanding the ecology and evolution of plant communication via airborne cues.

Photo-acoustic and video-acoustic methods for sensing distant sound sources

Science.gov (United States)

Slater, Dan; Kozacik, Stephen; Kelmelis, Eric

2017-05-01

Long range telescopic video imagery of distant terrestrial scenes, aircraft, rockets and other aerospace vehicles can be a powerful observational tool. But what about the associated acoustic activity? A new technology, Remote Acoustic Sensing (RAS), may provide a method to remotely listen to the acoustic activity near these distant objects. Local acoustic activity sometimes weakly modulates the ambient illumination in a way that can be remotely sensed. RAS is a new type of microphone that separates an acoustic transducer into two spatially separated components: 1) a naturally formed in situ acousto-optic modulator (AOM) located within the distant scene and 2) a remote sensing readout device that recovers the distant audio. These two elements are passively coupled over long distances at the speed of light by naturally occurring ambient light energy or other electromagnetic fields. Stereophonic, multichannel and acoustic beam forming are all possible using RAS techniques and when combined with high-definition video imagery it can help to provide a more cinema like immersive viewing experience. A practical implementation of a remote acousto-optic readout device can be a challenging engineering problem. The acoustic influence on the optical signal is generally weak and often with a strong bias term. The optical signal is further degraded by atmospheric seeing turbulence. In this paper, we consider two fundamentally different optical readout approaches: 1) a low pixel count photodiode based RAS photoreceiver and 2) audio extraction directly from a video stream. Most of our RAS experiments to date have used the first method for reasons of performance and simplicity. But there are potential advantages to extracting audio directly from a video stream. These advantages include the straight forward ability to work with multiple AOMs (useful for acoustic beam forming), simpler optical configurations, and a potential ability to use certain preexisting video recordings. However

ISAT: The mega-fauna acoustic tracking system

KAUST Repository

De la Torre, Pedro

2013-06-01

The acoustic tracking module of the Integrated Satellite and Acoustic Telemetry (iSAT) system is discussed in detail. iSAT is capable of detecting the relative direction of an acoustic source by measuring the order of arrival (OOA) of the acoustic signal to each hydrophone in a triangular array. The characteristics of the hydrophones, the projector, and the target acoustic signal used for iSAT are described. Initially it is designed to study the movements of whale sharks (Rhincodon typus), but it could potentially be used to describe high resolution movements of other marine species. © 2013 IEEE.

Wiener variable step size and gradient spectral variance smoothing for double-talk-robust acoustic echo cancellation and acoustic feedback cancellation

DEFF Research Database (Denmark)

Gil-Cacho, Jose M.; Van Waterschoot, Toon; Moonen, Marc

2014-01-01

Double-talk (DT)-robust acoustic echo cancellation (AEC) and acoustic feedback cancellation (AFC) are needed in speech communication systems, e.g., in hands-free communication systems and hearing aids. In this paper, we derive a practical and computationally efficient algorithm based...... model and in colored non-stationary noise....

4th International Conference on Communications, Signal Processing, and Systems

CERN Document Server

Mu, Jiasong; Wang, Wei; Zhang, Baoju

2016-01-01

This book brings together papers presented at the 4th International Conference on Communications, Signal Processing, and Systems, which provides a venue to disseminate the latest developments and to discuss the interactions and links between these multidisciplinary fields. Spanning topics ranging from Communications, Signal Processing and Systems, this book is aimed at undergraduate and graduate students in Electrical Engineering, Computer Science and Mathematics, researchers and engineers from academia and industry as well as government employees (such as NSF, DOD, DOE, etc).

Springer Handbook of Acoustics

CERN Document Server

Rossing, Thomas D

2007-01-01

Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and others. The Springer Handbook of Acoustics is an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents spanning: animal acoustics including infrasound and ultrasound, environmental noise control, music and human speech and singing, physiological and psychological acoustics, architectural acoustics, physical and engineering acoustics, signal processing, medical acoustics, and ocean acoustics. This handbook reviews the most important areas of acoustics, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest rese...

Retrograde Signals: Integrators of Interorganellar Communication and Orchestrators of Plant Development.

Science.gov (United States)

de Souza, Amancio; Wang, Jin-Zheng; Dehesh, Katayoon

2017-04-28

Interorganellar cooperation maintained via exquisitely controlled retrograde-signaling pathways is an evolutionary necessity for maintenance of cellular homeostasis. This signaling feature has therefore attracted much research attention aimed at improving understanding of the nature of these communication signals, how the signals are sensed, and ultimately the mechanism by which they integrate targeted processes that collectively culminate in organellar cooperativity. The answers to these questions will provide insight into how retrograde-signal-mediated regulatory mechanisms are recruited and which biological processes are targeted, and will advance our understanding of how organisms balance metabolic investments in growth against adaptation to environmental stress. This review summarizes the present understanding of the nature and the functional complexity of retrograde signals as integrators of interorganellar communication and orchestrators of plant development, and offers a perspective on the future of this critical and dynamic area of research.

Representation of acoustic signals in the eighth nerve of the Tokay gecko. II. Masking of pure tones with noise.

Science.gov (United States)

Sams-Dodd, F; Capranica, R R

1996-10-01

Acoustic signals are generally encoded in the peripheral auditory system of vertebrates by a duality scheme. For frequency components that fall within the excitatory tuning curve, individual eighth nerve fibers can encode the effective spectral energy by a spike-rate code, while simultaneously preserving the signal waveform periodicity of lower frequency components by phase-locked spike-train discharges. To explore how robust this duality of representation may be in the presence of noise, we recorded the responses of auditory fibers in the eighth nerve of the Tokay gecko to tonal stimuli when masking noise was added simultaneously. We found that their spike-rate functions reached plateau levels fairly rapidly in the presence of noise, so the ability to signal the presence of a tone by a concomitant change in firing rate was quickly lost. On the other hand, their synchronization functions maintained a high degree of phase-locked firings to the tone even in the presence of high-intensity masking noise, thus enabling a robust detection of the tonal signal. Critical ratios (CR) and critical bandwidths showed that in the frequency range where units are able to phaselock to the tonal periodicity, the CR bands were relatively narrow and the bandwidths were independent of noise level. However, to higher frequency tones where phaselocking fails and only spike-rate codes apply, the CR bands were much wider and depended upon noise level, so that their ability to filter tones out of a noisy background degraded with increasing noise levels. The greater robustness of phase-locked temporal encoding contrasted with spike-rate coding verifies a important advantage in using lower frequency signals for communication in noisy environments.

Radio Science from an Optical Communications Signal

Science.gov (United States)

Moision, Bruce; Asmar, Sami; Oudrhiri, Kamal

2013-01-01

NASA is currently developing the capability to deploy deep space optical communications links. This creates the opportunity to utilize the optical link to obtain range, doppler, and signal intensity estimates. These may, in turn, be used to complement or extend the capabilities of current radio science. In this paper we illustrate the achievable precision in estimating range, doppler, and received signal intensity of an non-coherent optical link (the current state-of-the-art for a deep-space link). We provide a joint estimation algorithm with performance close to the bound. We draw comparisons to estimates based on a coherent radio frequency signal, illustrating that large gains in either precision or observation time are possible with an optical link.

How do males of Hypsiboas goianus (Hylidae: Anura respond to conspecific acoustic stimuli?

Directory of Open Access Journals (Sweden)

Alessandro R. Morais

2015-12-01

Full Text Available ABSTRACT Acoustic communication plays an important role in the social behavior of anurans. Acoustic signals, which can be used in different contexts such as mate attraction and territory defense, may mediate social interactions among individuals. Herein, we used playback experiments to test whether males of Hypsiboas goianus (Lutz, 1968 change their vocal behavior in response to conspecific advertisement calls. Specifically, we used different field playback experiments in which we modified the time interval between advertisement calls to simulate males with distinct states of motivation (Sequence A and B. We did not observe differences in the acoustic response of males of H. goianus between the two types of field playback experiments. On the other hand, we observed that H. goianus males reduce the dominant frequency of the advertisement call and increase the rate of aggressive calls in response to a conspecific competitor. Our results suggest that the acoustic plasticity observed in males of H. goianus represents an aggressive response that allows repelling conspecific individuals.

Bilinear Time-frequency Analysis for Lamb Wave Signal Detected by Electromagnetic Acoustic Transducer

Science.gov (United States)

Sun, Wenxiu; Liu, Guoqiang; Xia, Hui; Xia, Zhengwu

2018-03-01

Accurate acquisition of the detection signal travel time plays a very important role in cross-hole tomography. The experimental platform of aluminum plate under the perpendicular magnetic field is established and the bilinear time-frequency analysis methods, Wigner-Ville Distribution (WVD) and the pseudo-Wigner-Ville distribution (PWVD), are applied to analyse the Lamb wave signals detected by electromagnetic acoustic transducer (EMAT). By extracting the same frequency component of the time-frequency spectrum as the excitation frequency, the travel time information can be obtained. In comparison with traditional linear time-frequency analysis method such as short-time Fourier transform (STFT), the bilinear time-frequency analysis method PWVD is more appropriate in extracting travel time and recognizing patterns of Lamb wave.

An Acoustic OFDM System with Symbol-by-Symbol Doppler Compensation for Underwater Communication.

Science.gov (United States)

MinhHai, Tran; Rie, Saotome; Suzuki, Taisaku; Wada, Tomohisa

2016-01-01

We propose an acoustic OFDM system for underwater communication, specifically for vertical link communications such as between a robot in the sea bottom and a mother ship in the surface. The main contributions are (1) estimation of time varying Doppler shift using continual pilots in conjunction with monitoring the drift of Power Delay Profile and (2) symbol-by-symbol Doppler compensation in frequency domain by an ICI matrix representing nonuniform Doppler. In addition, we compare our proposal against a resampling method. Simulation and experimental results confirm that our system outperforms the resampling method when the velocity changes roughly over OFDM symbols. Overall, experimental results taken in Shizuoka, Japan, show our system using 16QAM, and 64QAM achieved a data throughput of 7.5 Kbit/sec with a transmitter moving at maximum 2 m/s, in a complicated trajectory, over 30 m vertically.

Acoustic 3D imaging of dental structures

Energy Technology Data Exchange (ETDEWEB)

Lewis, D.K. [Lawrence Livermore National Lab., CA (United States); Hume, W.R. [California Univ., Los Angeles, CA (United States); Douglass, G.D. [California Univ., San Francisco, CA (United States)

1997-02-01

Our goals for the first year of this three dimensional electodynamic imaging project was to determine how to combine flexible, individual addressable; preprocessing of array source signals; spectral extrapolation or received signals; acoustic tomography codes; and acoustic propagation modeling code. We investigated flexible, individually addressable acoustic array material to find the best match in power, sensitivity and cost and settled on PVDF sheet arrays and 3-1 composite material.

Suppression of sound radiation to far field of near-field acoustic communication system using evanescent sound field

Science.gov (United States)

Fujii, Ayaka; Wakatsuki, Naoto; Mizutani, Koichi

2016-01-01

A method of suppressing sound radiation to the far field of a near-field acoustic communication system using an evanescent sound field is proposed. The amplitude of the evanescent sound field generated from an infinite vibrating plate attenuates exponentially with increasing a distance from the surface of the vibrating plate. However, a discontinuity of the sound field exists at the edge of the finite vibrating plate in practice, which broadens the wavenumber spectrum. A sound wave radiates over the evanescent sound field because of broadening of the wavenumber spectrum. Therefore, we calculated the optimum distribution of the particle velocity on the vibrating plate to reduce the broadening of the wavenumber spectrum. We focused on a window function that is utilized in the field of signal analysis for reducing the broadening of the frequency spectrum. The optimization calculation is necessary for the design of window function suitable for suppressing sound radiation and securing a spatial area for data communication. In addition, a wide frequency bandwidth is required to increase the data transmission speed. Therefore, we investigated a suitable method for calculating the sound pressure level at the far field to confirm the variation of the distribution of sound pressure level determined on the basis of the window shape and frequency. The distribution of the sound pressure level at a finite distance was in good agreement with that obtained at an infinite far field under the condition generating the evanescent sound field. Consequently, the window function was optimized by the method used to calculate the distribution of the sound pressure level at an infinite far field using the wavenumber spectrum on the vibrating plate. According to the result of comparing the distributions of the sound pressure level in the cases with and without the window function, it was confirmed that the area whose sound pressure level was reduced from the maximum level to -50 dB was

Skull's acoustic attenuation and dispersion modeling on photoacoustic signal

Science.gov (United States)

Mohammadi, Leila; Behnam, Hamid; Tavakkoli, Jahan; Nasiriavanaki, Mohammadreza

2018-02-01

Despite the promising results of the recent novel transcranial photoacoustic (PA) brain imaging technology, it has been demonstrated that the presence of the skull severely affects the performance of this imaging modality. We theoretically investigate the effects of acoustic heterogeneity induced by skull on the PA signals generated from single particles, with firstly developing a mathematical model for this phenomenon and then explore experimental validation of the results. The model takes into account the frequency dependent attenuation and dispersion effects occur with wave reflection, refraction and mode conversion at the skull surfaces. Numerical simulations based on the developed model are performed for calculating the propagation of photoacoustic waves through the skull. The results show a strong agreement between simulation and ex-vivo study. The findings are as follow: The thickness of the skull is the most PA signal deteriorating factor that affects both its amplitude (attenuation) and phase (distortion). Also we demonstrated that, when the depth of target region is low and it is comparable to the skull thickness, however, the skull-induced distortion becomes increasingly severe and the reconstructed image would be strongly distorted without correcting these effects. It is anticipated that an accurate quantification and modeling of the skull transmission effects would ultimately allow for aberration correction in transcranial PA brain imaging.

An Evaluation of the Acoustic Signal processing Techniques for Sodium-Water Reaction Detection in KALIMER-600

International Nuclear Information System (INIS)

Hur, Seop; Seong, S. H.; Kim, T. J.; Kim, S. O.; Lee, M. K.

2005-02-01

KALIMER-600 is a pool type fast breeder reactor using liquid sodium as a coolant. Although it has the several advantages such as long-term fuel cycle and enhanced safety concepts, it is possible to leak the secondary side water/steam into sodium boundary. This event could make the plant abnormal condition. One of the major design issues in KALIMER-600 is, therefore, to develop the system which can early detect the sodium-water reaction to protect the sodium-water reaction event. After evaluating the various signal processing techniques for passive acoustic leak detection, we have proposed the early leak detection logics. the signal processing techniques for evaluation were the spectral estimation using the linear modeling, the estimation error of linear modeling, the system adaptation rate using an adaptive signal processing, and the background noise cancellation using adaptive and fixed filtering. As the analysis results regarding the stationary and the cross-correlation of leak signals and background noises, the two signal systems met a wide-dense stationary process and there was only the week cross correlation relationship between two signals. It is ,therefore, possible to use the linear/harmonic modeling of signal systems, and the leak signal in sensor outputs can be discriminated. As the results of the evaluation of the various spectral estimation methods, the spectral estimation method based on autoregressive modeling was more practical comparing with other methods in the sodium-water reaction detection. The passive acoustic leak detection logics were suggested based on above evaluations. the logics consist of 3 levels; transient identification, leak determination and leak symptom identification. The simulation results using sodium-water reaction signals showed that it was possible to determine the leak at above -3dB of SNR, while between -3 dB and -10 dB of SNR the logics determined the leak symptom identification. The detection sensitivity can be enhanced

Acoustic emission signal measurements in pressure vessel testing

International Nuclear Information System (INIS)

Peter, A.

1984-01-01

The number of acoustic emission events per plastically deformed unit of volume caused by artificial notches in real pressure vessels has been calculated taking into account reference voltage, distance between acoustic emission source and sensor as well as the effect of noise background. A test performed at a 100 m 3 gasholder verifies the theoretical considerations. (author)

Software-based acoustical measurements

CERN Document Server

Miyara, Federico

2017-01-01

This textbook provides a detailed introduction to the use of software in combination with simple and economical hardware (a sound level meter with calibrated AC output and a digital recording system) to obtain sophisticated measurements usually requiring expensive equipment. It emphasizes the use of free, open source, and multiplatform software. Many commercial acoustical measurement systems use software algorithms as an integral component; however the methods are not disclosed. This book enables the reader to develop useful algorithms and provides insight into the use of digital audio editing tools to document features in the signal. Topics covered include acoustical measurement principles, in-depth critical study of uncertainty applied to acoustical measurements, digital signal processing from the basics, and metrologically-oriented spectral and statistical analysis of signals. The student will gain a deep understanding of the use of software for measurement purposes; the ability to implement software-based...

Calibration of acoustic emission transducers

International Nuclear Information System (INIS)

Leschek, W.C.

1976-01-01

A method is described for calibrating an acoustic emission transducer to be used in a pre-set frequency range. The absolute reception sensitivity of a reference transducer is determined at frequencies selected within the frequency range. The reference transducer and the acoustic emission transducer are put into acoustic communication with the surface of a limited acoustic medium representing an equivalent acoustic load appreciably identical to that of the medium in which the use of the acoustic emission transducer is intended. A blank random acoustic noise is emitted in the acoustic medium in order to establish a diffuse and reverberating sound field, after which the output responses of the reference transducer and of the acoustic emission transducer are obtained with respect to the diffuse and reverberating field, for selected frequencies. The output response of the acoustic emission transducer is compared with that of the reference transducer for the selected frequencies, so as to determine the reception sensitivity of the acoustic emission transducer [fr

Vocal communication in a complex multi-level society: constrained acoustic structure and flexible call usage in Guinea baboons.

Science.gov (United States)

Maciej, Peter; Ndao, Ibrahima; Hammerschmidt, Kurt; Fischer, Julia

2013-09-23

To understand the evolution of acoustic communication in animals, it is important to distinguish between the structure and the usage of vocal signals, since both aspects are subject to different constraints. In terrestrial mammals, the structure of calls is largely innate, while individuals have a greater ability to actively initiate or withhold calls. In closely related taxa, one would therefore predict a higher flexibility in call usage compared to call structure. In the present study, we investigated the vocal repertoire of free living Guinea baboons (Papio papio) and examined the structure and usage of the animals' vocal signals. Guinea baboons live in a complex multi-level social organization and exhibit a largely tolerant and affiliative social style, contrary to most other baboon taxa. To classify the vocal repertoire of male and female Guinea baboons, cluster analyses were used and focal observations were conducted to assess the usage of vocal signals in the particular contexts. In general, the vocal repertoire of Guinea baboons largely corresponded to the vocal repertoire other baboon taxa. The usage of calls, however, differed considerably from other baboon taxa and corresponded with the specific characteristics of the Guinea baboons' social behaviour. While Guinea baboons showed a diminished usage of contest and display vocalizations (a common pattern observed in chacma baboons), they frequently used vocal signals during affiliative and greeting interactions. Our study shows that the call structure of primates is largely unaffected by the species' social system (including grouping patterns and social interactions), while the usage of calls can be more flexibly adjusted, reflecting the quality of social interactions of the individuals. Our results support the view that the primary function of social signals is to regulate social interactions, and therefore the degree of competition and cooperation may be more important to explain variation in call usage

Wireless RF communication in biomedical applications

International Nuclear Information System (INIS)

Jones, Inke; Ricciardi, Lucas; Hall, Leonard; Enderling, Stefan; Saint, David; Al-Sarawi, Said; Abbott, Derek; Hansen, Hedley; Varadan, Vijay; Bertram, Chris; Maddocks, Simon

2008-01-01

This paper focuses on wireless transcutaneous RF communication in biomedical applications. It discusses current technology, restrictions and applications and also illustrates possible future developments. It focuses on the application in biotelemetry where the system consists of a transmitter and a receiver with a transmission link in between. The transmitted information can either be a biopotential or a nonelectric value like arterial pressure, respiration, body temperature or pH value. In this paper the use of radio-frequency (RF) communication and identification for those applications is described. Basically, radio-frequency identification or RFID is a technology that is analogous to the working principle of magnetic barcode systems. Unlike magnetic barcodes, passive RFID can be used in extreme climatic conditions—also the tags do not need to be within close proximity of the reader. Our proposed solution is to exploit an exciting new development in making circuits on polymers without the need for battery power. This solution exploits the principle of a surface acoustic wave (SAW) device on a polymer substrate. The SAW device is a set of interdigitated conducting fingers on the polymer substrate. If an appropriate RF signal is sent to the device, the fingers act as microantennas that pick up the signal, and this energy is then converted into acoustic waves that travel across the surface of the polymer substrate. Being a flexible polymer, the acoustic waves cause stresses that can either contract or stretch the material. In our case we mainly focus on an RF controllable microvalve that could ultimately be used for fertility control

Wireless RF communication in biomedical applications

Science.gov (United States)

Jones, Inke; Ricciardi, Lucas; Hall, Leonard; Hansen, Hedley; Varadan, Vijay; Bertram, Chris; Maddocks, Simon; Enderling, Stefan; Saint, David; Al-Sarawi, Said; Abbott, Derek

2008-02-01

This paper focuses on wireless transcutaneous RF communication in biomedical applications. It discusses current technology, restrictions and applications and also illustrates possible future developments. It focuses on the application in biotelemetry where the system consists of a transmitter and a receiver with a transmission link in between. The transmitted information can either be a biopotential or a nonelectric value like arterial pressure, respiration, body temperature or pH value. In this paper the use of radio-frequency (RF) communication and identification for those applications is described. Basically, radio-frequency identification or RFID is a technology that is analogous to the working principle of magnetic barcode systems. Unlike magnetic barcodes, passive RFID can be used in extreme climatic conditions—also the tags do not need to be within close proximity of the reader. Our proposed solution is to exploit an exciting new development in making circuits on polymers without the need for battery power. This solution exploits the principle of a surface acoustic wave (SAW) device on a polymer substrate. The SAW device is a set of interdigitated conducting fingers on the polymer substrate. If an appropriate RF signal is sent to the device, the fingers act as microantennas that pick up the signal, and this energy is then converted into acoustic waves that travel across the surface of the polymer substrate. Being a flexible polymer, the acoustic waves cause stresses that can either contract or stretch the material. In our case we mainly focus on an RF controllable microvalve that could ultimately be used for fertility control.

Signal post-processing for acoustic velocimeters: detecting and replacing spikes

International Nuclear Information System (INIS)

Razaz, Mahdi; Kawanisi, Kiyosi

2011-01-01

Time series recorded by acoustic velocimeters are often affected by a combination of factors, including turbulent velocity fluctuations, Doppler noise and signal aliasing. Although it is not possible to find a comprehensive threshold for identifying spurious data, the present work attempts to describe an effective technique for detecting spikes. This technique is based on transforming data into wavelet space and thresholding the wavelet basis by a consistent threshold. The universal threshold modified by a robust scale estimator such as Q n is proven to work extremely well. The suggested methods for replacing identified spikes combine times series analyses (linear time series modelling or a Kalman predictor) with a straightforward method, polynomial interpolation, to generate substitutions retaining both the trends and the fluctuations in the surrounding clean data. Then, tests were performed to reveal the influence of replacing methods on the total number of detected spikes, required iterations and physical properties of the restored signal. From the overall results, it is inferred that using the wavelet-Q n as the detecting module and integrating it with linear time series modelling/Kalman filtering as the replacement module constitutes an effective despiking algorithm. This methodology is capable of restoring the contaminated signal in such a way that its statistical and physical properties correlate well with those of the original record

Modeling skull's acoustic attenuation and dispersion on photoacoustic signal

Science.gov (United States)

Mohammadi, L.; Behnam, H.; Nasiriavanaki, M. R.

2017-03-01

Despite the great promising results of a recent new transcranial photoacoustic brain imaging technology, it has been shown that the presence of the skull severely affects the performance of this imaging modality. In this paper, we investigate the effect of skull on generated photoacoustic signals with a mathematical model. The developed model takes into account the frequency dependence attenuation and acoustic dispersion effects occur with the wave reflection and refraction at the skull surface. Numerical simulations based on the developed model are performed for calculating the propagation of photoacoustic waves through the skull. From the simulation results, it was found that the skull-induced distortion becomes very important and the reconstructed image would be strongly distorted without correcting these effects. In this regard, it is anticipated that an accurate quantification and modeling of the skull transmission effects would ultimately allow for skull aberration correction in transcranial photoacoustic brain imaging.

Acoustical conditions of typical classrooms in Hong Kong

Science.gov (United States)

Li, Kai Ming; Lam, Coriolanus C. L.

2005-04-01

This paper presents measurement results of the acoustical environments of local schools in Hong Kong. In the measurements, several acoustical aspects that affect verbal communication in classrooms have been studied. These conditions include outdoor and indoor ambient noise levels, signal-to-noise ratios, reverberation time and the speech transmission index. Typical classrooms in many different schools and other higher-education institutions have been selected in the present study. Experimental results are compared with such national standards as USA (ANSI S 12.60 V 2002), Australian/New Zealand (AS/NZS 2107:2000), China (GB/T 15508 V 1995) and other national and industrial standards. This study will form the basis of devising acceptable standards for use in Hong Kong. [Work supported by the Research Grants Council of the SAR Government, the Research Committee of the Hong Kong Polytechnic University and Architectural Services Department of the Hong Kong SAR Government.

Underwater acoustic channel properties in the Gulf of Naples and their effects on digital data transmission

Directory of Open Access Journals (Sweden)

G. Iannaccone

2007-06-01

Full Text Available In this paper we studied the physical properties of the Gulf of Naples (Southern Italy for its use as a communication channel for the acoustic transmission of digital data acquired by seismic instruments on the seafloor to a moored buoy. The acoustic link will be assured by high frequency acoustic modems operating with a central frequency of 100 kHz and a band pass of 10 kHz. Since the maximum depth of the sea is about 300 m and the planned horizontal distance between the seismic instruments and the buoy is 2 km, the acoustic data transmission shall be near horizontal. In this study the signal-to-noise ratio is plotted against depth and distance from the source, thus defining the limit after which the transmitted information becomes unreliable. Using ray-theory, we compute the amplitudes of a transmitted signal at a grid of 21×12 receivers to calculate the transmission loss at each receiver. The signal-to-noise ratio is finally computed for each receiver knowing also the transmitter source level and the acoustic noise level in the Gulf of Naples. The results show that the multipath effects predominate over the effects produced by the sound velocity gradient in the sea in the summer period. In the case of omnidirectional transmitters with a Source Level (SL of 165 dB and a bit rate of 2.4 kbit/s, the results also show that distances of 1400-1600 m can be reached throughout the year for transmitter-receiver connections below 50 m depth in the underwater acoustic channel.

An Acoustic OFDM System with Symbol-by-Symbol Doppler Compensation for Underwater Communication

Directory of Open Access Journals (Sweden)

Tran MinhHai

2016-01-01

Full Text Available We propose an acoustic OFDM system for underwater communication, specifically for vertical link communications such as between a robot in the sea bottom and a mother ship in the surface. The main contributions are (1 estimation of time varying Doppler shift using continual pilots in conjunction with monitoring the drift of Power Delay Profile and (2 symbol-by-symbol Doppler compensation in frequency domain by an ICI matrix representing nonuniform Doppler. In addition, we compare our proposal against a resampling method. Simulation and experimental results confirm that our system outperforms the resampling method when the velocity changes roughly over OFDM symbols. Overall, experimental results taken in Shizuoka, Japan, show our system using 16QAM, and 64QAM achieved a data throughput of 7.5 Kbit/sec with a transmitter moving at maximum 2 m/s, in a complicated trajectory, over 30 m vertically.

An Acoustic OFDM System with Symbol-by-Symbol Doppler Compensation for Underwater Communication

Science.gov (United States)

MinhHai, Tran; Rie, Saotome; Suzuki, Taisaku; Wada, Tomohisa

2016-01-01

We propose an acoustic OFDM system for underwater communication, specifically for vertical link communications such as between a robot in the sea bottom and a mother ship in the surface. The main contributions are (1) estimation of time varying Doppler shift using continual pilots in conjunction with monitoring the drift of Power Delay Profile and (2) symbol-by-symbol Doppler compensation in frequency domain by an ICI matrix representing nonuniform Doppler. In addition, we compare our proposal against a resampling method. Simulation and experimental results confirm that our system outperforms the resampling method when the velocity changes roughly over OFDM symbols. Overall, experimental results taken in Shizuoka, Japan, show our system using 16QAM, and 64QAM achieved a data throughput of 7.5 Kbit/sec with a transmitter moving at maximum 2 m/s, in a complicated trajectory, over 30 m vertically. PMID:27057558

Acoustic monitoring of rotating machine by advanced signal processing technology

International Nuclear Information System (INIS)

Kanemoto, Shigeru

2010-01-01

The acoustic data remotely measured by hand held type microphones are investigated for monitoring and diagnosing the rotational machine integrity in nuclear power plants. The plant operator's patrol monitoring is one of the important activities for condition monitoring. However, remotely measured sound has some difficulties to be considered for precise diagnosis or quantitative judgment of rotating machine anomaly, since the measurement sensitivity is different in each measurement, and also, the sensitivity deteriorates in comparison with an attached type sensor. Hence, in the present study, several advanced signal processing methods are examined and compared in order to find optimum anomaly monitoring technology from the viewpoints of both sensitivity and robustness of performance. The dimension of pre-processed signal feature patterns are reduced into two-dimensional space for the visualization by using the standard principal component analysis (PCA) or the kernel based PCA. Then, the normal state is classified by using probabilistic neural network (PNN) or support vector data description (SVDD). By using the mockup test facility of rotating machine, it is shown that the appropriate combination of the above algorithms gives sensitive and robust anomaly monitoring performance. (author)

ECS: Efficient Communication Scheduling for Underwater Sensor Networks

Directory of Open Access Journals (Sweden)

Lu Hong

2011-03-01

Full Text Available TDMA protocols have attracted a lot of attention for underwater acoustic sensor networks (UWSNs, because of the unique characteristics of acoustic signal propagation such as great energy consumption in transmission, long propagation delay and long communication range. Previous TDMA protocols all allocated transmission time to nodes based on discrete time slots. This paper proposes an efficient continuous time scheduling TDMA protocol (ECS for UWSNs, including the continuous time based and sender oriented conflict analysis model, the transmission moment allocation algorithm and the distributed topology maintenance algorithm. Simulation results confirm that ECS improves network throughput by 20% on average, compared to existing MAC protocols.

Mechanical Seal Opening Condition Monitoring Based on Acoustic Emission Technology

Directory of Open Access Journals (Sweden)

Erqing Zhang

2014-06-01

Full Text Available Since the measurement of mechanical sealing film thickness and just-lift-off time is very difficult, the sealing film condition monitoring method based on acoustic emission signal is proposed. The mechanical seal acoustic emission signal present obvious characteristics of time-varying nonlinear and pulsating. In this paper, the acoustic emission signal is used to monitor the seal end faces just-lift-off time and friction condition. The acoustic emission signal is decomposed by empirical mode decomposition into a series of intrinsic mode function with independent characteristics of different time scales and different frequency band. The acoustic emission signal only generated by end faces friction is obtained by eliminating the false intrinsic mode function components. The correlation coefficient of acoustic emission signal and Multi-scale Laplace Wavelet is calculated. It is proved that the maximum frequency (8000 Hz of the correlation coefficient is appeared at the spindle speed of 300 rpm. And at this time (300 rpm the end faces have just lifted off. By a set of mechanical oil seal running test, it is demonstrated that this method could accurately identify mechanical seal end faces just-lift-off time and friction condition.

Biochar and microbial signaling: production conditions determine effects on microbial communication

Science.gov (United States)

Masiello, Caroline A.; Chen, Ye; Gao, Xiaodong; Liu, Shirley; Cheng, Hsiao-Ying; Bennett, Matthew R.; Rudgers, Jennifer A.; Wagner, Daniel S.; Zygourakis, Kyriacos; Silberg, Jonathan J.

2013-01-01

Charcoal has a long soil residence time, which has resulted in its production and use as a carbon sequestration technique (biochar). A range of biological effects can be triggered by soil biochar that can positively and negatively influence carbon storage, such as changing the decomposition rate of organic matter and altering plant biomass production. Sorption of cellular signals has been hypothesized to underlie some of these effects, but it remains unknown whether the binding of biochemical signals occurs, and if so, on time scales relevant to microbial growth and communication. We examined biochar sorption of N-3-oxo-dodecanoyl-L-homoserine lactone, an acyl-homoserine lactone (AHL) intercellular signaling molecule used by many gram-negative soil microbes to regulate gene expression. We show that wood biochars disrupt communication within a growing multicellular system that is made up of sender cells that synthesize AHL and receiver cells that express green fluorescent protein in response to an AHL signal. However, biochar inhibition of AHL-mediated cell-cell communication varied, with the biochar prepared at 700°C (surface area of 301 m2/g) inhibiting cellular communication 10-fold more than an equivalent mass of biochar prepared at 300°C (surface area of 3 m2/g). These findings provide the first direct evidence that biochars elicit a range of effects on gene expression dependent on intercellular signaling, implicating the method of biochar preparation as a parameter that could be tuned to regulate microbial-dependent soil processes, like nitrogen fixation and pest attack of root crops. PMID:24066613

Biochar and microbial signaling: production conditions determine effects on microbial communication.

Science.gov (United States)

Masiello, Caroline A; Chen, Ye; Gao, Xiaodong; Liu, Shirley; Cheng, Hsiao-Ying; Bennett, Matthew R; Rudgers, Jennifer A; Wagner, Daniel S; Zygourakis, Kyriacos; Silberg, Jonathan J

2013-10-15

Charcoal has a long soil residence time, which has resulted in its production and use as a carbon sequestration technique (biochar). A range of biological effects can be triggered by soil biochar that can positively and negatively influence carbon storage, such as changing the decomposition rate of organic matter and altering plant biomass production. Sorption of cellular signals has been hypothesized to underlie some of these effects, but it remains unknown whether the binding of biochemical signals occurs, and if so, on time scales relevant to microbial growth and communication. We examined biochar sorption of N-3-oxo-dodecanoyl-L-homoserine lactone, an acyl-homoserine lactone (AHL) intercellular signaling molecule used by many gram-negative soil microbes to regulate gene expression. We show that wood biochars disrupt communication within a growing multicellular system that is made up of sender cells that synthesize AHL and receiver cells that express green fluorescent protein in response to an AHL signal. However, biochar inhibition of AHL-mediated cell-cell communication varied, with the biochar prepared at 700 °C (surface area of 301 m(2)/g) inhibiting cellular communication 10-fold more than an equivalent mass of biochar prepared at 300 °C (surface area of 3 m(2)/g). These findings provide the first direct evidence that biochars elicit a range of effects on gene expression dependent on intercellular signaling, implicating the method of biochar preparation as a parameter that could be tuned to regulate microbial-dependent soil processes, like nitrogen fixation and pest attack of root crops.

Statistical Modeling of Large-Scale Signal Path Loss in Underwater Acoustic Networks

Directory of Open Access Journals (Sweden)

Manuel Perez Malumbres

2013-02-01

Full Text Available In an underwater acoustic channel, the propagation conditions are known to vary in time, causing the deviation of the received signal strength from the nominal value predicted by a deterministic propagation model. To facilitate a large-scale system design in such conditions (e.g., power allocation, we have developed a statistical propagation model in which the transmission loss is treated as a random variable. By applying repetitive computation to the acoustic field, using ray tracing for a set of varying environmental conditions (surface height, wave activity, small node displacements around nominal locations, etc., an ensemble of transmission losses is compiled and later used to infer the statistical model parameters. A reasonable agreement is found with log-normal distribution, whose mean obeys a log-distance increases, and whose variance appears to be constant for a certain range of inter-node distances in a given deployment location. The statistical model is deemed useful for higher-level system planning, where simulation is needed to assess the performance of candidate network protocols under various resource allocation policies, i.e., to determine the transmit power and bandwidth allocation necessary to achieve a desired level of performance (connectivity, throughput, reliability, etc..

Detection of geodesic acoustic mode oscillations, using multiple signal classification analysis of Doppler backscattering signal on Tore Supra

International Nuclear Information System (INIS)

Vermare, L.; Hennequin, P.; Gürcan, Ö.D.

2012-01-01

This paper presents the first observation of geodesic acoustic modes (GAMs) on Tore Supra plasmas. Using the Doppler backscattering system, the oscillations of the plasma flow velocity, localized between r/a = 0.85 and r/a = 0.95, and with a frequency, typically around 10 kHz, have been observed at the plasma edge in numerous discharges. When the additional heating power is varied, the frequency is found to scale with C s /R. The MUltiple SIgnal Classification (MUSIC) algorithm is employed to access the temporal evolution of the perpendicular velocity of density fluctuations. The method is presented in some detail, and is validated and compared against standard methods, such as the conventional fast Fourier transform method, using a synthetic signal. It stands out as a powerful data analysis method to follow the Doppler frequency with a high temporal resolution, which is important in order to extract the dynamics of GAMs. (paper)

Compressing Sensing Based Source Localization for Controlled Acoustic Signals Using Distributed Microphone Arrays

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Wei Ke

2017-01-01

Full Text Available In order to enhance the accuracy of sound source localization in noisy and reverberant environments, this paper proposes an adaptive sound source localization method based on distributed microphone arrays. Since sound sources lie at a few points in the discrete spatial domain, our method can exploit this inherent sparsity to convert the localization problem into a sparse recovery problem based on the compressive sensing (CS theory. In this method, a two-step discrete cosine transform- (DCT- based feature extraction approach is utilized to cover both short-time and long-time properties of acoustic signals and reduce the dimensions of the sparse model. In addition, an online dictionary learning (DL method is used to adjust the dictionary for matching the changes of audio signals, and then the sparse solution could better represent location estimations. Moreover, we propose an improved block-sparse reconstruction algorithm using approximate l0 norm minimization to enhance reconstruction performance for sparse signals in low signal-noise ratio (SNR conditions. The effectiveness of the proposed scheme is demonstrated by simulation results and experimental results where substantial improvement for localization performance can be obtained in the noisy and reverberant conditions.

Acoustic Particle Detection with the ANTARES Detector

Directory of Open Access Journals (Sweden)

M. Neff

2010-01-01

Full Text Available The (Antares Modules for Acoustic Detection Under the Sea AMADEUS system within the (Astronomy with a Neutrino Telescope and Abyss environmental RESsearch ANTARES neutrino telescope is designed to investigate detection techniques for acoustic signals produced by particle cascades. While passing through a liquid a cascade deposits energy and produces a measurable pressure pulse. This can be used for the detection of neutrinos with energies exceeding 1018 eV. The AMADEUS setup consists of 36 hydrophones grouped in six local clusters measuring about one cubic meter each. This article focuses on acoustic particle detection, the hardware of the AMADEUS detector and techniques used for acoustic signal processing.

Acoustic Particle Detection with the ANTARES Detector

Directory of Open Access Journals (Sweden)

Richardt C

2010-01-01

Full Text Available The (Antares Modules for Acoustic Detection Under the Sea AMADEUS system within the (Astronomy with a Neutrino Telescope and Abyss environmental RESsearch ANTARES neutrino telescope is designed to investigate detection techniques for acoustic signals produced by particle cascades. While passing through a liquid a cascade deposits energy and produces a measurable pressure pulse. This can be used for the detection of neutrinos with energies exceeding  eV. The AMADEUS setup consists of 36 hydrophones grouped in six local clusters measuring about one cubic meter each. This article focuses on acoustic particle detection, the hardware of the AMADEUS detector and techniques used for acoustic signal processing.

Acoustic signal propagation and measurement in natural stream channels for application to surrogate bed load measurements: Halfmoon Creek, Colorado

Science.gov (United States)

Monitoring sediment-generated noise using submerged hydrophones is a surrogate method for measuring bed load transport in streams with the potential for improving estimates of bed load transport through widespread, inexpensive monitoring. Understanding acoustic signal propagation in natural stream e...

Novel Fiber-Optic Ring Acoustic Emission Sensor.

Science.gov (United States)

Wei, Peng; Han, Xiaole; Xia, Dong; Liu, Taolin; Lang, Hao

2018-01-13

Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

Damage Detection Method of Wind Turbine Blade Using Acoustic Emission Signal Mapping

Energy Technology Data Exchange (ETDEWEB)

Han, Byeong Hee; Yoon, Dong JIn [Korea Research Institute of Standards and Seience, Daejeon (Korea, Republic of)

2011-02-15

Acoustic emission(AE) has emerged as a powerful nondestructive tool to detect any further growth or expansion of preexisting defects or to characterize failure mechanisms. Recently, this kind of technique, that is an in-situ monitoring of inside damages of materials or structures, becomes increasingly popular for monitoring the integrity of large structures like a huge wind turbine blade. Therefore, it is required to find a symptom of damage propagation before catastrophic failure through a continuous monitoring. In this study, a new damage location method has been proposed by using signal napping algorithm, and an experimental verification is conducted by using small wind turbine blade specimen: a part of 750 kW real blade. The results show that this new signal mapping method has high advantages such as a flexibility for sensor location, improved accuracy, high detectability. The newly proposed method was compared with traditional AE source location method based on arrival time difference

Digital sonar design in underwater acoustics principles and applications

CERN Document Server

Li, Qihu

2012-01-01

"Digital Sonar Design in Underwater Acoustics Principles and Applications" provides comprehensive and up-to-date coverage of research on sonar design, including the basic theory and techniques of digital signal processing, basic concept of information theory, ocean acoustics, underwater acoustic signal propagation theory, and underwater signal processing theory. This book discusses the general design procedure and approaches to implementation, the design method, system simulation theory and techniques, sonar tests in the laboratory, lake and sea, and practical validation criteria and methods for digital sonar design. It is intended for researchers in the fields of underwater signal processing and sonar design, and also for navy officers and ocean explorers. Qihu Li is a professor at the Institute of Acoustics, Chinese Academy of Sciences, and an academician of the Chinese Academy of Sciences.

On the relationship between input parameters in two-mass vocal-fold model with acoustical coupling an signal parameters of the glottal flow

NARCIS (Netherlands)

van Hirtum, Annemie; Lopez, Ines; Hirschberg, Abraham; Pelorson, Xavier

2003-01-01

In this paper the sensitivity of the two-mass model with acoustical coupling to the model input-parameters is assessed. The model-output or the glottal volume air flow is characterised by signal-parameters in the time-domain. The influence of changing input-parameters on the signal-parameters is

FAULT DETECTION AND LOCALIZATION IN MOTORCYCLES BASED ON THE CHAIN CODE OF PSEUDOSPECTRA AND ACOUSTIC SIGNALS

Directory of Open Access Journals (Sweden)

B. S. Anami

2013-06-01

Full Text Available Vehicles produce sound signals with varying temporal and spectral properties under different working conditions. These sounds are indicative of the condition of the engine. Fault diagnosis is a significantly difficult task in geographically remote places where expertise is scarce. Automated fault diagnosis can assist riders to assess the health condition of their vehicles. This paper presents a method for fault detection and location in motorcycles based on the chain code of the pseudospectra and Mel-frequency cepstral coefficient (MFCC features of acoustic signals. The work comprises two stages: fault detection and fault location. The fault detection stage uses the chain code of the pseudospectrum as a feature vector. If the motorcycle is identified as faulty, the MFCCs of the same sample are computed and used as features for fault location. Both stages employ dynamic time warping for the classification of faults. Five types of faults in motorcycles are considered in this work. Observed classification rates are over 90% for the fault detection stage and over 94% for the fault location stage. The work identifies other interesting applications in the development of acoustic fingerprints for fault diagnosis of machinery, tuning of musical instruments, medical diagnosis, etc.

De-Dopplerization of Acoustic Measurements

Science.gov (United States)

2017-08-10

accurate measurement of aircraft location to resample the time signal to account for the compression and expansion of acoustic wavefronts. Correcting...AFRL-RH-WP-TR-2017-0043 DE-DOPPLERIZATION OF ACOUSTIC MEASUREMENTS Frank Mobley, PhD 711 HPW/RHCB Wright-Patterson AFB OH...TITLE AND SUBTITLE DE-DOPPLERIZATION OF ACOUSTIC MEASUREMENTS 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER

Acoustic Ecology and Remote Acoustic Monitoring of a Minke Whale Population

National Research Council Canada - National Science Library

Gedamke, Jason

2000-01-01

Sound is the most effective means of communication in the ocean. A uniquely inquisitive minke whale population on the northern Great Barrier Reef presents an unprecedented research opportunity to study minke acoustics...

Acoustic constituents of prosodic typology

Science.gov (United States)

Komatsu, Masahiko

Different languages sound different, and considerable part of it derives from the typological difference of prosody. Although such difference is often referred to as lexical accent types (stress accent, pitch accent, and tone; e.g. English, Japanese, and Chinese respectively) and rhythm types (stress-, syllable-, and mora-timed rhythms; e.g. English, Spanish, and Japanese respectively), it is unclear whether these types are determined in terms of acoustic properties, The thesis intends to provide a potential basis for the description of prosody in terms of acoustics. It argues for the hypothesis that the source component of the source-filter model (acoustic features) approximately corresponds to prosody (linguistic features) through several experimental-phonetic studies. The study consists of four parts. (1) Preliminary experiment: Perceptual language identification tests were performed using English and Japanese speech samples whose frequency spectral information (i.e. non-source component) is heavily reduced. The results indicated that humans can discriminate languages with such signals. (2) Discussion on the linguistic information that the source component contains: This part constitutes the foundation of the argument of the thesis. Perception tests of consonants with the source signal indicated that the source component carries the information on broad categories of phonemes that contributes to the creation of rhythm. (3) Acoustic analysis: The speech samples of Chinese, English, Japanese, and Spanish, differing in prosodic types, were analyzed. These languages showed difference in acoustic characteristics of the source component. (4) Perceptual experiment: A language identification test for the above four languages was performed using the source signal with its acoustic features parameterized. It revealed that humans can discriminate prosodic types solely with the source features and that the discrimination is easier as acoustic information increases. The

A Support Vector Learning-Based Particle Filter Scheme for Target Localization in Communication-Constrained Underwater Acoustic Sensor Networks.

Science.gov (United States)

Li, Xinbin; Zhang, Chenglin; Yan, Lei; Han, Song; Guan, Xinping

2017-12-21

Target localization, which aims to estimate the location of an unknown target, is one of the key issues in applications of underwater acoustic sensor networks (UASNs). However, the constrained property of an underwater environment, such as restricted communication capacity of sensor nodes and sensing noises, makes target localization a challenging problem. This paper relies on fractional sensor nodes to formulate a support vector learning-based particle filter algorithm for the localization problem in communication-constrained underwater acoustic sensor networks. A node-selection strategy is exploited to pick fractional sensor nodes with short-distance pattern to participate in the sensing process at each time frame. Subsequently, we propose a least-square support vector regression (LSSVR)-based observation function, through which an iterative regression strategy is used to deal with the distorted data caused by sensing noises, to improve the observation accuracy. At the same time, we integrate the observation to formulate the likelihood function, which effectively update the weights of particles. Thus, the particle effectiveness is enhanced to avoid "particle degeneracy" problem and improve localization accuracy. In order to validate the performance of the proposed localization algorithm, two different noise scenarios are investigated. The simulation results show that the proposed localization algorithm can efficiently improve the localization accuracy. In addition, the node-selection strategy can effectively select the subset of sensor nodes to improve the communication efficiency of the sensor network.

Acoustic observations of internal tides and tidal currents in shallow water.

Science.gov (United States)

Turgut, Altan; Mignerey, Peter C; Goldstein, David J; Schindall, Jeffrey A

2013-04-01

Significant acoustic travel-time variability and frequency shifts of acoustic intensity level curves in broadband signal spectrograms were measured in the East China Sea during the summer of 2008. The broadband pulses (270-330 Hz) were transmitted from a fixed source and received at a bottomed horizontal array, located at the 33 km range. The acoustic intensity level curves of the received signals indicate regular frequency shifts that are well correlated with the measured internal tides. Similarly, regular travel-time shifts of the acoustic mode arrivals correlate well with the barotropic tides and can be explained by tidal currents along the acoustic propagation track. These observations indicate the potential of monitoring internal tides and tidal currents using low-frequency acoustic signals propagating at long ranges.

Perception of male caller identity in Koalas (Phascolarctos cinereus): acoustic analysis and playback experiments.

Science.gov (United States)

Charlton, Benjamin D; Ellis, William A H; McKinnon, Allan J; Brumm, Jacqui; Nilsson, Karen; Fitch, W Tecumseh

2011-01-01

The ability to signal individual identity using vocal signals and distinguish between conspecifics based on vocal cues is important in several mammal species. Furthermore, it can be important for receivers to differentiate between callers in reproductive contexts. In this study, we used acoustic analyses to determine whether male koala bellows are individually distinctive and to investigate the relative importance of different acoustic features for coding individuality. We then used a habituation-discrimination paradigm to investigate whether koalas discriminate between the bellow vocalisations of different male callers. Our results show that male koala bellows are highly individualized, and indicate that cues related to vocal tract filtering contribute the most to vocal identity. In addition, we found that male and female koalas habituated to the bellows of a specific male showed a significant dishabituation when they were presented with bellows from a novel male. The significant reduction in behavioural response to a final rehabituation playback shows this was not a chance rebound in response levels. Our findings indicate that male koala bellows are highly individually distinctive and that the identity of male callers is functionally relevant to male and female koalas during the breeding season. We go on to discuss the biological relevance of signalling identity in this species' sexual communication and the potential practical implications of our findings for acoustic monitoring of male population levels.

Perception of male caller identity in Koalas (Phascolarctos cinereus: acoustic analysis and playback experiments.

Directory of Open Access Journals (Sweden)

Benjamin D Charlton

Full Text Available The ability to signal individual identity using vocal signals and distinguish between conspecifics based on vocal cues is important in several mammal species. Furthermore, it can be important for receivers to differentiate between callers in reproductive contexts. In this study, we used acoustic analyses to determine whether male koala bellows are individually distinctive and to investigate the relative importance of different acoustic features for coding individuality. We then used a habituation-discrimination paradigm to investigate whether koalas discriminate between the bellow vocalisations of different male callers. Our results show that male koala bellows are highly individualized, and indicate that cues related to vocal tract filtering contribute the most to vocal identity. In addition, we found that male and female koalas habituated to the bellows of a specific male showed a significant dishabituation when they were presented with bellows from a novel male. The significant reduction in behavioural response to a final rehabituation playback shows this was not a chance rebound in response levels. Our findings indicate that male koala bellows are highly individually distinctive and that the identity of male callers is functionally relevant to male and female koalas during the breeding season. We go on to discuss the biological relevance of signalling identity in this species' sexual communication and the potential practical implications of our findings for acoustic monitoring of male population levels.

Parallel feedback active noise control of MRI acoustic noise with signal decomposition using hybrid RLS-NLMS adaptive algorithms.

Science.gov (United States)

Ganguly, Anshuman; Krishna Vemuri, Sri Hari; Panahi, Issa

2014-01-01

This paper presents a cost-effective adaptive feedback Active Noise Control (FANC) method for controlling functional Magnetic Resonance Imaging (fMRI) acoustic noise by decomposing it into dominant periodic components and residual random components. Periodicity of fMRI acoustic noise is exploited by using linear prediction (LP) filtering to achieve signal decomposition. A hybrid combination of adaptive filters-Recursive Least Squares (RLS) and Normalized Least Mean Squares (NLMS) are then used to effectively control each component separately. Performance of the proposed FANC system is analyzed and Noise attenuation levels (NAL) up to 32.27 dB obtained by simulation are presented which confirm the effectiveness of the proposed FANC method.

Detection method of internal leakage from valve using acoustic method

International Nuclear Information System (INIS)

Kumagai, Horomichi

1990-01-01

The purpose of this study is to estimate the availability of acoustic method for detecting the internal leakage of valves at power plants. Experiments have been carried out on the characteristics of acoustic noise caused by the leak simulated flow. From the experimental results, the mechanism of the acoustic noisegenerated from flow, the relation between acoustic intensity and leak flow velocity, and the characteristics of the acoustic frequency spectrum were clarified. The acoustic method was applied to valves at site, and the background noises were measured in abnormal plant conditions. When the background level is higher than the acoustic signal, the difference between the background noise frequency spectrum and the acoustic signal spectrum provide a very useful leak detection method. (author)

Detection method of internal leakage from valve using acoustic method

International Nuclear Information System (INIS)

Kumagai, Hiromichi; Kitajima, Akira; Suzuki, Akio.

1990-01-01

The objective of this study is to estimate the feasibility of the acoustic method for the internal leakage from the valves in power plants. From the experimental results, it was suggested that the acoustic method for the monitoring of leakage was feasible. When the background levels are higher than the acoustic signals from leakage, we can detect the leakage analyzing the spectrum of the remainders which take the background noise from the acoustic signals. (author)

Energy-Efficient Channel Coding Strategy for Underwater Acoustic Networks

Directory of Open Access Journals (Sweden)

Grasielli Barreto

2017-03-01

Full Text Available Underwater acoustic networks (UAN allow for efficiently exploiting and monitoring the sub-aquatic environment. These networks are characterized by long propagation delays, error-prone channels and half-duplex communication. In this paper, we address the problem of energy-efficient communication through the use of optimized channel coding parameters. We consider a two-layer encoding scheme employing forward error correction (FEC codes and fountain codes (FC for UAN scenarios without feedback channels. We model and evaluate the energy consumption of different channel coding schemes for a K-distributed multipath channel. The parameters of the FEC encoding layer are optimized by selecting the optimal error correction capability and the code block size. The results show the best parameter choice as a function of the link distance and received signal-to-noise ratio.

A Hierarchical Communication Architecture for Oceanic Surveillance Applications

Science.gov (United States)

Macias, Elsa; Suarez, Alvaro; Chiti, Francesco; Sacco, Andrea; Fantacci, Romano

2011-01-01

The interest in monitoring applications using underwater sensor networks has been growing in recent years. The severe communication restrictions imposed by underwater channels make that efficient monitoring be a challenging task. Though a lot of research has been conducted on underwater sensor networks, there are only few concrete applications to a real-world case study. In this work, hence, we propose a general three tier architecture leveraging low cost wireless technologies for acoustic communications between underwater sensors and standard technologies, Zigbee and Wireless Fidelity (WiFi), for water surface communications. We have selected a suitable Medium Access Control (MAC) layer, after making a comparison with some common MAC protocols. Thus the performance of the overall system in terms of Signals Discarding Rate (SDR), signalling delay at the surface gateway as well as the percentage of true detection have been evaluated by simulation, pointing out good results which give evidence in applicability’s favour. PMID:22247669

Springer handbook of acoustics

CERN Document Server

2014-01-01

Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and electronics. The Springer Handbook of Acoustics is also in his 2nd edition an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents. This new edition of the Handbook features over 11 revised and expanded chapters, new illustrations, and 2 new chapters covering microphone arrays  and acoustic emission.  Updated chapters contain the latest research and applications in, e.g. sound propagation in the atmosphere, nonlinear acoustics in fluids, building and concert hall acoustics, signal processing, psychoacoustics, computer music, animal bioacousics, sound intensity, modal acoustics as well as new chapters on microphone arrays an...

Novel Fiber-Optic Ring Acoustic Emission Sensor

Directory of Open Access Journals (Sweden)

Peng Wei

2018-01-01

Full Text Available Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

Transition section for acoustic waveguides

International Nuclear Information System (INIS)

Karplus, H.H.B.

1975-01-01

A means of facilitating the transmission of acoustic waves with minimal reflection between two regions having different specific acoustic impedances is described comprising a region exhibiting a constant product of cross-sectional area and specific acoustic impedance at each cross-sectional plane along the axis of the transition region. A variety of structures that exhibit this feature is disclosed, the preferred embodiment comprising a nested structure of doubly reentrant cones. This structure is useful for monitoring the operation of nuclear reactors in which random acoustic signals are generated in the course of operation

Acoustic remote sensing of ocean flows

Digital Repository Service at National Institute of Oceanography (India)

Joseph, A.; Desa, E.

Acoustic techniques have become powerful tools for measurement of ocean circulation mainly because of the ability of acoustic signals to travel long distances in water, and the inherently non-invasive nature of measurement. The satellite remote...

Laser-induced acoustic imaging of underground objects

Science.gov (United States)

Li, Wen; DiMarzio, Charles A.; McKnight, Stephen W.; Sauermann, Gerhard O.; Miller, Eric L.

1999-02-01

This paper introduces a new demining technique based on the photo-acoustic interaction, together with results from photo- acoustic experiments. We have buried different types of targets (metal, rubber and plastic) in different media (sand, soil and water) and imaged them by measuring reflection of acoustic waves generated by irradiation with a CO2 laser. Research has been focused on the signal acquisition and signal processing. A deconvolution method using Wiener filters is utilized in data processing. Using a uniform spatial distribution of laser pulses at the ground's surface, we obtained 3D images of buried objects. The images give us a clear representation of the shapes of the underground objects. The quality of the images depends on the mismatch of acoustic impedance of the buried objects, the bandwidth and center frequency of the acoustic sensors and the selection of filter functions.

Frequency Analysis of Acoustic Emission Signal to Monitor Damage Evolution in Masonry Structures

International Nuclear Information System (INIS)

Masera, D; Bocca, P; Grazzini, A

2011-01-01

A crucial aspect in damage evaluation of masonry structures is the analysis of long-term behaviour and for this reason fatigue analysis has a great influence on safety assessment of this structures. Acoustic Emission (AE) are very effective non-destructive techniques applied to identify micro and macro-defects and their temporal evolution in several materials. This technique permits to estimate the velocity of ultrasound waves propagation and the amount of energy released during fracture propagation to obtain information on the criticality of the ongoing process. By means of AE monitoring, an experimental analysis on a set of reinforced and unreinforced masonry walls under variable amplitude and static loading has been carried out. During these tests, the AE signals were recorded. The AE signals were analysed using Fast Fourier Transform (FFT) to examine the frequency distribution of the micro and macro cracking. It possible to evaluate the evolution of the wavelength of the AE signal through the two characteristic peak in the AE spectrum signals and the wave speed of the P or S waves. This wavelength evolution can be represent the microcrak and macrocrack evolution in masonry walls. This procedure permits to estimate the fracture dimension characteristic in several loading condition and for several masonry reinforced condition.

On the relationship between input parameters in the two-mass vocal-fold model with acoustical coupling and signal parameters of the glottal flow

NARCIS (Netherlands)

Hirtum, van A.; Lopez Arteaga, I.; Hirschberg, A.; Pelorson, X.

2003-01-01

In this paper the sensitivity of the two-mass model with acoustical coupling to the model input-parameters is assessed. The model-output or the glottal volume air flow is characterised by signal-parameters in the time-domain. The influence of changing input-parameters on the signal-parameters is

Communicative Signals Promote Object Recognition Memory and Modulate the Right Posterior STS.

Science.gov (United States)

Redcay, Elizabeth; Ludlum, Ruth S; Velnoskey, Kayla R; Kanwal, Simren

2016-01-01

Detection of communicative signals is thought to facilitate knowledge acquisition early in life, but less is known about the role these signals play in adult learning or about the brain systems supporting sensitivity to communicative intent. The current study examined how ostensive gaze cues and communicative actions affect adult recognition memory and modulate neural activity as measured by fMRI. For both the behavioral and fMRI experiments, participants viewed a series of videos of an actress acting on one of two objects in front of her. Communicative context in the videos was manipulated in a 2 × 2 design in which the actress either had direct gaze (Gaze) or wore a visor (NoGaze) and either pointed at (Point) or reached for (Reach) one of the objects (target) in front of her. Participants then completed a recognition memory task with old (target and nontarget) objects and novel objects. Recognition memory for target objects in the Gaze conditions was greater than NoGaze, but no effects of gesture type were seen. Similarly, the fMRI video-viewing task revealed a significant effect of Gaze within right posterior STS (pSTS), but no significant effects of Gesture. Furthermore, pSTS sensitivity to Gaze conditions was related to greater memory for objects viewed in Gaze, as compared with NoGaze, conditions. Taken together, these results demonstrate that the ostensive, communicative signal of direct gaze preceding an object-directed action enhances recognition memory for attended items and modulates the pSTS response to object-directed actions. Thus, establishment of a communicative context through ostensive signals remains an important component of learning and memory into adulthood, and the pSTS may play a role in facilitating this type of social learning.

Reconstruction of chaotic signals with applications to chaos-based communications

CERN Document Server

Feng, Jiu Chao

2008-01-01

This book provides a systematic review of the fundamental theory of signal reconstruction and the practical techniques used in reconstructing chaotic signals. Specific applications of signal reconstruction methods in chaos-based communications are expounded in full detail, along with examples illustrating the various problems associated with such applications.The book serves as an advanced textbook for undergraduate and graduate courses in electronic and information engineering, automatic control, physics and applied mathematics. It is also highly suited for general nonlinear scientists who wi

Shaping communicative colour signals over evolutionary time

Science.gov (United States)

Oyola Morales, José R.; Vital-García, Cuauhcihuatl; Hews, Diana K.; Martins, Emília P.

2016-01-01

Many evolutionary forces can shape the evolution of communicative signals, and the long-term impact of each force may depend on relative timing and magnitude. We use a phylogenetic analysis to infer the history of blue belly patches of Sceloporus lizards, and a detailed spectrophotometric analysis of four species to explore the specific forces shaping evolutionary change. We find that the ancestor of Sceloporus had blue patches. We then focus on four species; the first evolutionary shift (captured by comparison of S. merriami and S. siniferus) represents an ancient loss of the belly patch by S. siniferus, and the second evolutionary shift, bounded by S. undulatus and S. virgatus, represents a more recent loss of blue belly patch by S. virgatus. Conspicuousness measurements suggest that the species with the recent loss (S. virgatus) is the least conspicuous. Results for two other species (S. siniferus and S. merriami) suggest that over longer periods of evolutionary time, new signal colours have arisen which minimize absolute contrast with the habitat while maximizing conspicuousness to a lizard receiver. Specifically, males of the species representing an ancient loss of blue patch (S. siniferus) are more conspicuous than are females in the UV, whereas S. merriami males have evolved a green element that makes their belly patches highly sexually dimorphic but no more conspicuous than the white bellies of S. merriami females. Thus, our results suggest that natural selection may act more immediately to reduce conspicuousness, whereas sexual selection may have a more complex impact on communicative signals through the introduction of new colours. PMID:28018661

Acoustic sequences in non-human animals: a tutorial review and prospectus

Science.gov (United States)

Kershenbaum, Arik; Blumstein, Daniel T.; Roch, Marie A.; Akçay, Çağlar; Backus, Gregory; Bee, Mark A.; Bohn, Kirsten; Cao, Yan; Carter, Gerald; Cäsar, Cristiane; Coen, Michael; DeRuiter, Stacy L.; Doyle, Laurance; Edelman, Shimon; Ferrer-i-Cancho, Ramon; Freeberg, Todd M.; Garland, Ellen C.; Gustison, Morgan; Harley, Heidi E.; Huetz, Chloé; Hughes, Melissa; Bruno, Julia Hyland; Ilany, Amiyaal; Jin, Dezhe Z.; Johnson, Michael; Ju, Chenghui; Karnowski, Jeremy; Lohr, Bernard; Manser, Marta B.; McCowan, Brenda; Mercado, Eduardo; Narins, Peter M.; Piel, Alex; Rice, Megan; Salmi, Roberta; Sasahara, Kazutoshi; Sayigh, Laela; Shiu, Yu; Taylor, Charles; Vallejo, Edgar E.; Waller, Sara; Zamora-Gutierrez, Veronica

2015-01-01

Animal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well-known example of birdsong, other animals such as insects, amphibians, and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise – let alone understand – the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our review aims to outline suitable methods for testing these hypotheses, and to describe the major limitations to our current and near-future knowledge on questions of acoustic sequences. This review and prospectus is the result of a collaborative effort between 43 scientists from the fields of animal behaviour, ecology and evolution, signal processing, machine learning, quantitative linguistics, and information theory, who gathered for a 2013 workshop entitled, “Analysing vocal sequences in animals”. Our goal is to present not just a review of the state of the art, but to propose a methodological framework that summarises what we suggest are the best practices for research in this field, across taxa and across disciplines. We also provide a tutorial-style introduction to some of the most promising algorithmic approaches for analysing sequences. We divide our review into three sections: identifying the distinct units of an acoustic sequence, describing the different ways that information can be contained within a sequence, and analysing the structure of that sequence. Each of these sections is further subdivided to address the key questions and approaches in that area. We propose a uniform, systematic, and comprehensive approach to studying sequences, with the goal of clarifying

Nearshore Navigation and Communication Based on Deliberate EM Signals and Theoretical, Numerical and Observational Studies of Coastal Ocean Electrdynamics

National Research Council Canada - National Science Library

Sanford, Thomas B; Tyler, Robert H

2005-01-01

...) and other autonomous sensor systems, such as moored instruments. There is a need for non-acoustical methods to navigate and control AUVs, communicate with autonomous instruments, and detect submerged and buried objects in shallow water...

Method and apparatus for generating acoustic waves

International Nuclear Information System (INIS)

Rao, G.V.; Gopal, R.

1982-01-01

A portable source of acoustic waves comprises a sample of iron-nickel alloy including an austenite phase cooled to become martensite, and a wave guide to transmit the acoustic waves. The source is applied to the pressure boundary region of a pressurized water reactor to simulate an actual metal flaw and test the calibration of the monitoring and surveillance system. With at most 29.7% nickel in the sample, the source provides acoustic emission due to ductile deformation, and with at least 30% nickel the acoustic emission is characteristic of a brittle deformation. Thus, the monitoring and surveillance system can be tested in either or both situations. In the prior art, synthetic waveform signals were used for such calibration but found not suitable for on-line simulation of the surveillance system. This invention provides an improved system in that it generates true acoustic signals. (author)

Acoustic discrimination of Southern Ocean zooplankton

Science.gov (United States)

Brierley, Andrew S.; Ward, Peter; Watkins, Jonathan L.; Goss, Catherine

Acoustic surveys in the vicinity of the sub-Antarctic island of South Georgia during a period of exceptionally calm weather revealed the existence of a number of horizontally extensive yet vertically discrete scattering layers in the upper 250 m of the water column. These layers were fished with a Longhurst-Hardy plankton recorder (LHPR) and a multiple-opening 8 m 2 rectangular mid-water trawl (RMT8). Analysis of catches suggested that each scattering layer was composed predominantly of a single species (biovolume>95%) of either the euphausiids Euphausia frigida or Thysanöessa macrura, the hyperiid amphipod Themisto gaudichaudii, or the eucalaniid copepod Rhincalanus gigas. Instrumentation on the nets allowed their trajectories to be reconstructed precisely, and thus catch data to be related directly to the corresponding acoustic signals. Discriminant function analysis of differences between mean volume backscattering strength at 38, 120 and 200 kHz separated echoes originating from each of the dominant scattering layers, and other signals identified as originating from Antarctic krill ( Euphausia superba), with an overall correct classification rate of 77%. Using echo intensity data alone, gathered using hardware commonly employed for fishery acoustics, it is therefore possible to discriminate in situ between several zooplanktonic taxa, taxa which in some instances exhibit similar gross morphological characteristics and have overlapping length- frequency distributions. Acoustic signals from the mysid Antarctomysis maxima could also be discriminated once information on target distribution was considered, highlighting the value of incorporating multiple descriptors of echo characteristics into signal identification procedures. The ability to discriminate acoustically between zooplankton taxa could be applied to provide improved acoustic estimates of species abundance, and to enhance field studies of zooplankton ecology, distribution and species interactions.

Potential of acoustic monitoring for safety assessment of primary system

International Nuclear Information System (INIS)

Olma, B.J.

1997-01-01

Safety assessment of the primary system and its components with respect to their mechanical integrity is increasingly supported by acoustic signature analysis during power operation of the plants. Acoustic signals of Loose Parts Monitoring System sensors are continuously monitored by dedicated digital systems for signal bursts associated with metallic impacts. Several years of ISTec/GRS experience and the practical use of its digital systems MEDEA and RAMSES have shown that acoustic monitoring is very successful for detecting component failures at an early stage. Advanced powerful tools for classification and acoustic evaluation of burst signals have recently been realized. The paper presents diagnosis experiences of BWR's and PWR's safety assessment. (author). 7 refs, 8 figs

A combined method for analysis of the acoustic emission signals from aboveground storage tank bottom

Energy Technology Data Exchange (ETDEWEB)

Yewei Kang; Mingchun Ling; Min Xiong; Yi Sun; Dongjie Tan [PetroChina Pipeline R and D Center, Langfang (China)

2009-07-01

In the late 1980s acoustic emission (AE) technology was first used to assess the corrosion of aboveground storage tank (AST) bottoms. From then on, it attracts great attention because it can do in-service inspection. Recognizing and eliminating noise is still the main challenge due to the small size of the signals in the presence of potential process noise when the AE signals are processed. In this paper a method combining pattern recognition with traditional AE parametric analysis is introduced to assess the corrosion of AST bottom. First, the AE signals are clustered in different clusters by a clustering method based on the distances of AE signal features. The reasonable cluster is selected for next analysis step. Second, a statistical method is used to evaluate the activities of AE on which the final evaluation report is based. Practical inspection is done on a large oil storage tank in the Chongqing distribution station of Lanzhou- Chengdu-Chongqing product oil pipeline of PetroChina Pipeline Company. The analytical result indicates that the combined method is reliable and feasible. (author)

Effect of Ionosphere on Geostationary Communication Satellite Signals

Science.gov (United States)

Erdem, Esra; Arikan, Feza; Gulgonul, Senol

2016-07-01

Geostationary orbit (GEO) communications satellites allow radio, television, and telephone transmissions to be sent live anywhere in the world. They are extremely important in daily life and also for military applications. Since, satellite communication is an expensive technology addressing crowd of people, it is critical to improve the performance of this technology. GEO satellites are at 35,786 kilometres from Earth's surface situated directly over the equator. A satellite in a geostationary orbit (GEO) appears to stand still in the sky, in a fixed position with respect to an observer on the earth, because the satellite's orbital period is the same as the rotation rate of the Earth. The advantage of this orbit is that ground antennas can be fixed to point towards to satellite without their having to track the satellite's motion. Radio frequency ranges used in satellite communications are C, X, Ku, Ka and even EHG and V-band. Satellite signals are disturbed by atmospheric effects on the path between the satellite and the receiver antenna. These effects are mostly rain, cloud and gaseous attenuation. It is expected that ionosphere has a minor effect on the satellite signals when the ionosphere is quiet. But there are anomalies and perturbations on the structure of ionosphere with respect to geomagnetic field and solar activity and these conditions may cause further affects on the satellite signals. In this study IONOLAB-RAY algorithm is adopted to examine the effect of ionosphere on satellite signals. IONOLAB-RAY is developed to calculate propagation path and characteristics of high frequency signals. The algorithm does not have any frequency limitation and models the plasmasphere up to 20,200 km altitude, so that propagation between a GEO satellite and antenna on Earth can be simulated. The algorithm models inhomogeneous, anisotropic and time dependent structure of the ionosphere with a 3-D spherical grid geometry and calculates physical parameters of the

Organelle communication: signaling crossroads between homeostasis and disease.

Science.gov (United States)

Bravo-Sagua, Roberto; Torrealba, Natalia; Paredes, Felipe; Morales, Pablo E; Pennanen, Christian; López-Crisosto, Camila; Troncoso, Rodrigo; Criollo, Alfredo; Chiong, Mario; Hill, Joseph A; Simmen, Thomas; Quest, Andrew F; Lavandero, Sergio

2014-05-01

Cellular organelles do not function as isolated or static units, but rather form dynamic contacts between one another that can be modulated according to cellular needs. The physical interfaces between organelles are important for Ca2+ and lipid homeostasis, and serve as platforms for the control of many essential functions including metabolism, signaling, organelle integrity and execution of the apoptotic program. Emerging evidence also highlights the importance of organelle communication in disorders such as Alzheimer's disease, pulmonary arterial hypertension, cancer, skeletal and cardiac muscle dysfunction. Here, we provide an overview of the current literature on organelle communication and the link to human pathologies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Acoustic emission

International Nuclear Information System (INIS)

Straus, A.; Lopez Pumarega, M.I.; Di Gaetano, J.O.; D'Atellis, C.E.; Ruzzante, J.E.

1990-01-01

This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

Acoustic emission evolution during sliding friction of Hadfield steel single crystal

Science.gov (United States)

Lychagin, D. V.; Novitskaya, O. S.; Kolubaev, A. V.; Sizova, O. V.

2017-12-01

Friction is a complex dynamic process. Direct observation of processes occurring in the friction zone is impossible due to a small size of a real contact area and, as a consequence, requires various additional methods applicable to monitor a tribological contact state. One of such methods consists in the analysis of acoustic emission data of a tribological contact. The use of acoustic emission entails the problem of interpreting physical sources of signals. In this paper, we analyze the evolution of acoustic emission signal frames in friction of Hadfield steel single crystals. The chosen crystallographic orientation of single crystals enables to identify four stages related to friction development as well as acoustic emission signals inherent in these stages. Acoustic emission signal parameters are studied in more detail by the short-time Fourier transform used to determine the time variation of the median frequency and its power spectrum. The results obtained will facilitate the development of a more precise method to monitor the tribological contact based on the acoustic emission method.

The availability of the detection method of internal valve leakage using acoustic method

International Nuclear Information System (INIS)

Kumagai, Hiromichi; Suzuki, Akio

1989-01-01

The purpose of this study is to estimate the availability of acoustic method to the internal leakage of the valves at power plants. The acoustic method was applied to the valves at the site, and the background noise was measured for the abnormal plantcondition. From the comparison of the background noise date with the experimental results as to relation between leakage flow and acoust signal, the minimum leakage flow rates that can be detected by the acoust signal was suggested. When the background levels are higher than the acoust signal, the method described below was considered that the analysis the remainder among the background noise frequency spectrum and the acoustic signal spectrum become a very useful leak detection method. A few experimental examples of the spectrum analysis that varied the background noise characteristic were given. (author)

Interaction of electromagnetic and acoustic waves in a stochastic atmosphere

Science.gov (United States)

Bhatnagar, N.; Peterson, A. M.

1979-01-01

In the Stanford radio acoustic sounding system (RASS) an electromagnetic signal is made to scatter from a moving acoustic pulse train. Under a Bragg-scatter condition maximum electromagnetic scattering occurs. The scattered radio signal contains temperature and wind information as a function of the acoustic-pulse position. In this investigation RASS performance is assessed in an atmosphere characterized by the presence of turbulence and mean atmospheric parameters. The only assumption made is that the electromagnetic wave is not affected by stochastic perturbations in the atmosphere. It is concluded that the received radio signal depends strongly on the intensity of turbulence for altitudes of the acoustic pulse greater than the coherence length of propagation. The effect of mean vertical wind and mean temperature on the strength of the received signal is also demonstrated to be insignificant. Mean horizontal winds, however, shift the focus of the reflected electromagnetic energy from its origin, resulting in a decrease in received signal level when a monostatic radio-frequency (RF) system is used. For a bistatic radar configuration with space diversified receiving antennas, the shifting of the acoustic pulse makes possible the remote measurement of the horizontal wind component.

The Prediction of Metal Slopping in LD Converter on Base an Acoustic Signal

Directory of Open Access Journals (Sweden)

Kostúr, K.

2006-01-01

Full Text Available The negative influences of slopping in a BOF are pollution to the environment. They give lower yield and cause equipment damage. The prediction of these phenomena is based on information processing from the measuring microphone. The change of frequency in certain range is done by a signal for the prediction of slopping. In this paper two methods for prediction of slopping are described. The first method is based on measuring and processing of sound emitted from the vessel during the blow. The second method utilizes Fourier’s transformation for processing of acoustic signal from sonic meter. The success rate of prediction has been evaluated by help of five criterions. It is possible to forecast the slopping on selected frequency (band. It is the essence of the second method, because this method has high success (criterion K1. Note, that criterion K5 defines acknowledgment of duration slopping. This criterion has the highest value.

Levitation of objects using acoustic energy

Science.gov (United States)

Whymark, R. R.

1975-01-01

Activated sound source establishes standing-wave pattern in gap between source and acoustic reflector. Solid or liquid material introduced in region will move to one of the low pressure areas produced at antinodes and remain suspended as long as acoustic signal is present.

Metasurface-based angle-selective multichannel acoustic refractor

Science.gov (United States)

Liu, Bingyi; Jiang, Yongyuan

2018-05-01

We theoretically study the angle-selective refractions of an impedance-matched acoustic gradient-index metasurface, which is integrated with a rigid bar array of a deep subwavelength period. An interesting refraction order appears under the all-angle incidence despite the existence of a critical angle, and notably, the odevity of the phase-discretization level apparently selects the transmitted diffraction orders. We utilize the strategy of multilayered media design to realize a three-channel acoustic refractor, which shows good promise for constructing multifunctional diffractive acoustic elements for acoustic communication.

Analysis of acoustic emission signals of fatigue crack growth and corrosion processes. Investigation of the possibilities for continuous condition monitoring of transport containers by acoustic emission testing; Analyse der Schallemissionssignale aus Ermuedungsrisswachstum und Korrosionsprozessen. Untersuchung der Moeglichkeiten fuer die kontinuierliche Zustandsueberwachung von Transportbehaeltern mittels Schallemissionspruefung

Energy Technology Data Exchange (ETDEWEB)

Wachsmuth, Janne

2016-05-01

Fatigue crack growth and active corrosion processes are the main causes of structural failures of transport products like road tankers, railway tank cars and ships. To prevent those failures, preventive, time-based maintenance is performed. However, preventive inspections are costly and include the risk of not detecting a defect, which could lead to a failure within the next service period. An alternative is the idea of continuous monitoring of the whole structure by means of acoustic emission testing (AT). With AT, defects within the material shall be detected and repaired directly after their appearance. Acoustic emission testing is an online non-destructive testing method. Acoustic emission (AE) arises from changes within the material and is transported by elastic waves through the material. If the AE event generates enough energy, the elastic wave propagates to the boundaries of the component, produces a displacement in the picometre scale and can be detected by a piezoelectric sensor. The sensor produces an electrical signal. From this AE signal, AE features such as the maximum amplitude or the frequency can be extracted. Methods of signal analysis are used to investigate the time and frequency dependency of signal groups. The purpose of the signal analysis is to connect the AE signal with the originating AE source. If predefined damage mechanisms are identified, referencing the damage condition of the structure is possible. Acoustic emission from events of the actual crack propagation process can for example lead to the crack growth rate or the stress intensity factor, both specific values from fracture mechanics. A new development in the domain of acoustic emission testing is the pattern recognition of AE signals. Specific features are extracted from the AE signals to assign them to their damage mechanisms. In this thesis the AE signals from the damage mechanisms corrosion and fatigue crack growth are compared and analysed. The damage mechanisms were

Acoustic emission intrusion detector

International Nuclear Information System (INIS)

Carver, D.W.; Whittaker, J.W.

1980-01-01

An intrusion detector is provided for detecting a forcible entry into a secured structure while minimizing false alarms. The detector uses a piezoelectric crystal transducer to sense acoustic emissions. The transducer output is amplified by a selectable gain amplifier to control the sensitivity. The rectified output of the amplifier is applied to a Schmitt trigger circuit having a preselected threshold level to provide amplitude discrimination. Timing circuitry is provided which is activated by successive pulses from the Schmitt trigger which lie within a selected time frame for frequency discrimination. Detected signals having proper amplitude and frequency trigger an alarm within the first complete cycle time of a detected acoustical disturbance signal

Generation of thermo-acoustic waves from pulsed solar/IR radiation

Science.gov (United States)

Rahman, Aowabin

Acoustic waves could potentially be used in a wide range of engineering applications; however, the high energy consumption in generating acoustic waves from electrical energy and the cost associated with the process limit the use of acoustic waves in industrial processes. Acoustic waves converted from solar radiation provide a feasible way of obtaining acoustic energy, without relying on conventional nonrenewable energy sources. One of the goals of this thesis project was to experimentally study the conversion of thermal to acoustic energy using pulsed radiation. The experiments were categorized into "indoor" and "outdoor" experiments, each with a separate experimental setup. The indoor experiments used an IR heater to power the thermo-acoustic lasers and were primarily aimed at studying the effect of various experimental parameters on the amplitude of sound waves in the low frequency range (below 130 Hz). The IR radiation was modulated externally using a chopper wheel and then impinged on a porous solid, which was housed inside a thermo-acoustic (TA) converter. A microphone located at a certain distance from the porous solid inside the TA converter detected the acoustic signals. The "outdoor" experiments, which were targeted at TA conversion at comparatively higher frequencies (in 200 Hz-3 kHz range) used solar energy to power the thermo-acoustic laser. The amplitudes (in RMS) of thermo-acoustic signals obtained in experiments using IR heater as radiation source were in the 80-100 dB range. The frequency of acoustic waves corresponded to the frequency of interceptions of the radiation beam by the chopper. The amplitudes of acoustic waves were influenced by several factors, including the chopping frequency, magnitude of radiation flux, type of porous material, length of porous material, external heating of the TA converter housing, location of microphone within the air column, and design of the TA converter. The time-dependent profile of the thermo-acoustic signals

4th Pacific Rim Underwater Acoustics Conference

CERN Document Server

Xu, Wen; Cheng, Qianliu; Zhao, Hangfang

2016-01-01

These proceedings are a collection of 16 selected scientific papers and reviews by distinguished international experts that were presented at the 4th Pacific Rim Underwater Acoustics Conference (PRUAC), held in Hangzhou, China in October 2013. The topics discussed at the conference include internal wave observation and prediction; environmental uncertainty and coupling to sound propagation; environmental noise and ocean dynamics; dynamic modeling in acoustic fields; acoustic tomography and ocean parameter estimation; time reversal and matched field processing; underwater acoustic localization and communication as well as measurement instrumentations and platforms. These proceedings provide insights into the latest developments in underwater acoustics, promoting the exchange of ideas for the benefit of future research.

Acoustic cardiac signals analysis: a Kalman filter–based approach

Directory of Open Access Journals (Sweden)

Salleh SH

2012-06-01

for the given measurement. The model is formulated into state-space form to enable use of a Kalman filter to estimate the clean cycles of heart sounds. The estimates obtained by Kalman filtering are optimal in mean squared sense.Keywords: heart sound, murmurs, ECG, Kalman filters, acoustic cardiac signals

Sophisticated Communication in the Brazilian Torrent Frog Hylodes japi.

Science.gov (United States)

de Sá, Fábio P; Zina, Juliana; Haddad, Célio F B

2016-01-01

Intraspecific communication in frogs plays an important role in the recognition of conspecifics in general and of potential rivals or mates in particular and therefore with relevant consequences for pre-zygotic reproductive isolation. We investigate intraspecific communication in Hylodes japi, an endemic Brazilian torrent frog with territorial males and an elaborate courtship behavior. We describe its repertoire of acoustic signals as well as one of the most complex repertoires of visual displays known in anurans, including five new visual displays. Previously unknown in frogs, we also describe a bimodal inter-sexual communication system where the female stimulates the male to emit a courtship call. As another novelty for frogs, we show that in addition to choosing which limb to signal with, males choose which of their two vocal sacs will be used for visual signaling. We explain how and why this is accomplished. Control of inflation also provides additional evidence that vocal sac movement and color must be important for visual communication, even while producing sound. Through the current knowledge on visual signaling in Neotropical torrent frogs (i.e. hylodids), we discuss and highlight the behavioral diversity in the family Hylodidae. Our findings indicate that communication in species of Hylodes is undoubtedly more sophisticated than we expected and that visual communication in anurans is more widespread than previously thought. This is especially true in tropical regions, most likely due to the higher number of species and phylogenetic groups and/or to ecological factors, such as higher microhabitat diversity.

Sophisticated Communication in the Brazilian Torrent Frog Hylodes japi.

Directory of Open Access Journals (Sweden)

Fábio P de Sá

Full Text Available Intraspecific communication in frogs plays an important role in the recognition of conspecifics in general and of potential rivals or mates in particular and therefore with relevant consequences for pre-zygotic reproductive isolation. We investigate intraspecific communication in Hylodes japi, an endemic Brazilian torrent frog with territorial males and an elaborate courtship behavior. We describe its repertoire of acoustic signals as well as one of the most complex repertoires of visual displays known in anurans, including five new visual displays. Previously unknown in frogs, we also describe a bimodal inter-sexual communication system where the female stimulates the male to emit a courtship call. As another novelty for frogs, we show that in addition to choosing which limb to signal with, males choose which of their two vocal sacs will be used for visual signaling. We explain how and why this is accomplished. Control of inflation also provides additional evidence that vocal sac movement and color must be important for visual communication, even while producing sound. Through the current knowledge on visual signaling in Neotropical torrent frogs (i.e. hylodids, we discuss and highlight the behavioral diversity in the family Hylodidae. Our findings indicate that communication in species of Hylodes is undoubtedly more sophisticated than we expected and that visual communication in anurans is more widespread than previously thought. This is especially true in tropical regions, most likely due to the higher number of species and phylogenetic groups and/or to ecological factors, such as higher microhabitat diversity.

NEMO-SMO acoustic array: A deep-sea test of a novel acoustic positioning system for a km3-scale underwater neutrino telescope

Science.gov (United States)

Viola, S.; Ardid, M.; Bertin, V.; Enzenhöfer, A.; Keller, P.; Lahmann, R.; Larosa, G.; Llorens, C. D.; NEMO Collaboration; SMO Collaboration

2013-10-01

Within the activities of the NEMO project, the installation of a 8-floors tower (NEMO-Phase II) at a depth of 3500 m is foreseen in 2012. The tower will be installed about 80 km off-shore Capo Passero, in Sicily. On board the NEMO tower, an array of 18 acoustic sensors will be installed, permitting acoustic detection of biological sources, studies for acoustic neutrino detection and primarily acoustic positioning of the underwater structures. For the latter purpose, the sensors register acoustic signals emitted by five acoustic beacons anchored on the sea-floor. The data acquisition system of the acoustic sensors is fully integrated with the detector data transport system and is based on an “all data to shore” philosophy. Signals coming from hydrophones are continuously sampled underwater at 192 kHz/24 bit and transmitted to shore through an electro-optical cable for real-time analysis. A novel technology for underwater GPS time-stamping of data has been implemented and tested. The operation of the acoustic array will permit long-term test of sensors and electronics technologies that are proposed for the acoustic positioning system of KM3NeT.

Proposed frustrated-total-reflection acoustic sensing method

International Nuclear Information System (INIS)

Hull, J.R.

1981-01-01

Modulation of electromagnetic energy transmission through a frustrated-total-reflection device by pressure-induced changes in the index of refraction is proposed for use as an acoustic detector. Maximum sensitivity occurs for angles of incidence near the critical angle. The minimum detectable pressure in air is limited by Brownian noise. Acoustic propagation losses and diffraction of the optical beam by the acoustic signal limit the minimum acoustic wavelength to lengths of the order of the spatial extent of the optical beam. The response time of the method is fast enough to follow individual acoustic waves

Adenylate Kinase and AMP Signaling Networks: Metabolic Monitoring, Signal Communication and Body Energy Sensing

Directory of Open Access Journals (Sweden)

Andre Terzic

2009-04-01

Full Text Available Adenylate kinase and downstream AMP signaling is an integrated metabolic monitoring system which reads the cellular energy state in order to tune and report signals to metabolic sensors. A network of adenylate kinase isoforms (AK1-AK7 are distributed throughout intracellular compartments, interstitial space and body fluids to regulate energetic and metabolic signaling circuits, securing efficient cell energy economy, signal communication and stress response. The dynamics of adenylate kinase-catalyzed phosphotransfer regulates multiple intracellular and extracellular energy-dependent and nucleotide signaling processes, including excitation-contraction coupling, hormone secretion, cell and ciliary motility, nuclear transport, energetics of cell cycle, DNA synthesis and repair, and developmental programming. Metabolomic analyses indicate that cellular, interstitial and blood AMP levels are potential metabolic signals associated with vital functions including body energy sensing, sleep, hibernation and food intake. Either low or excess AMP signaling has been linked to human disease such as diabetes, obesity and hypertrophic cardiomyopathy. Recent studies indicate that derangements in adenylate kinase-mediated energetic signaling due to mutations in AK1, AK2 or AK7 isoforms are associated with hemolytic anemia, reticular dysgenesis and ciliary dyskinesia. Moreover, hormonal, food and antidiabetic drug actions are frequently coupled to alterations of cellular AMP levels and associated signaling. Thus, by monitoring energy state and generating and distributing AMP metabolic signals adenylate kinase represents a unique hub within the cellular homeostatic network.

Radiation-induced perturbation of cell-to-cell signalling and communication

International Nuclear Information System (INIS)

Mariotti, L.; Facoetti, A.; Bertolotti, A.; Ranza, E.; Alloni, D.; Ottolenghi, A.

2011-01-01

The investigation of the bystander phenomena (i.e. the induction of damage in cells not directly traversed by radiation) is strictly related to the study of the mechanisms of intercellular communication and of the perturbative effects of radiation. A new possible way to try to solve the bystander puzzle is through a 'systems radiation biology' approach with the total integration of experimental and theoretical activities. In particular, this contribution will focus on: (1) 'ad hoc' experiments designed to quantify key parameters involved in intercellular signalling (focusing, as a pilot study, on release, decay and internalization of interleukin-6 molecules, their modulation by radiation, and possible differences between in vivo/in vitro behaviour); (2) the implementation and the development of two different modelling approaches: a stochastic model (based on a Monte Carlo code) that takes account of the local mechanisms of release and internalization of signalling molecules (e.g. cytokines) and an analytical model where signal molecules are treated as a population and their temporal behaviour is described by differential equations. This approach provided instruments to investigate the complex phenomena of signal transmission and the role of cell communication to guarantee (maintain) the robustness of the in vitro experimental systems against the effects of perturbations. (authors)

Reproducible Data Processing Research for the CABRI R.I.A. experiments Acoustic Emission signal analysis

Energy Technology Data Exchange (ETDEWEB)

Pantera, Laurent [CEA, DEN, CAD/DER/SRES/LPRE, Cadarache, F-13108 Saint-Paul-lez-Durance (France); Issiaka Traore, Oumar [Laboratory of Machanics and Acoustics (LMA) CNRS, 13402 Marseille (France)

2015-07-01

The CABRI facility is an experimental nuclear reactor of the French Atomic Energy Commission (CEA) designed to study the behaviour of fuel rods at high burnup under Reactivity Initiated Accident (R.I.A.) conditions such as the scenario of a control rod ejection. During the experimental phase, the behaviour of the fuel element generates acoustic waves which can be detected by two microphones placed upstream and downstream from the test device. Studies carried out on the last fourteen tests showed the interest in carrying out temporal and spectral analyses on these signals by showing the existence of signatures which can be correlated with physical phenomena. We want presently to return to this rich data in order to have a new point of view by applying modern signal processing methods. Such an antecedent works resumption leads to some difficulties. Although all the raw data are accessible in the form of text files, analyses and graphics representations were not clear in reproducing from the former studies since the people who were in charge of the original work have left the laboratory and it is not easy when time passes, even with our own work, to be able to remember the steps of data manipulations and the exact setup. Thus we decided to consolidate the availability of the data and its manipulation in order to provide a robust data processing workflow to the experimentalists before doing any further investigations. To tackle this issue of strong links between data, treatments and the generation of documents, we adopted a Reproducible Research paradigm. We shall first present the tools chosen in our laboratory to implement this workflow and, then we shall describe the global perception carried out to continue the study of the Acoustic Emission signals recorded by the two microphones during the last fourteen CABRI R.I.A. tests. (authors)

Experience with digital acoustic monitoring systems for PWRs and BWRs

International Nuclear Information System (INIS)

Olma, B.J.

1998-01-01

Substantial progress could be reached both in system technics and in application of digital acoustic monitoring systems for assessing mechanical integrity of reactor primary systems. For the surveillance of PWRs and BWRs during power operation of the plants, acoustic signals of Loose Parts Monitoring System sensors are continuously monitored for signal bursts associated with metallic impacts. ISTec/GRS experience with its digital systems MEDEA and RAMSES has shown that acoustic signature analysis is very successful for detecting component failures at an early stage. Methods for trending and classification of digital burst signals are shown, experience with their practical use will be presented. (author)

Molecular diagnostics reveal spiders that exploit prey vibrational signals used in sexual communication.

Science.gov (United States)

Virant-Doberlet, Meta; King, R Andrew; Polajnar, Jernej; Symondson, William O C

2011-05-01

Vibrational signalling is a widespread form of animal communication and, in the form of sexual communication, has been generally regarded as inherently short-range and a private communication channel, free from eavesdropping by generalist predators. A combination of fieldwork and laboratory experiments was used to test the hypothesis that predators can intercept and exploit such signals. First, we developed and characterized PCR primers specific for leafhoppers of the genus Aphrodes and specifically for the species Aphrodes makarovi. Spiders were collected from sites where leafhoppers were present and screened with these primers to establish which spider species were significant predators of this species during the mating period of these leafhoppers. Analysis using PCR of the gut contents of tangle-web spiders, Enoplognatha ovata (Theridiidae), showed that they consume leafhoppers in the field at a greater rate when signalling adults were present than when nymphs were dominant, suggesting that the spiders were using these vibrations signals to find their prey. Playback and microcosm experiments then showed that E. ovata can use the vibrational signals of male leafhoppers as a cue during foraging and, as a result, killed significantly more male than female A. makarovi. Our results show, for the first time, that arthropod predators can exploit prey vibrational communication to obtain information about prey availability and use this information to locate and capture prey. This may be a widespread mechanism for prey location, one that is likely to be a major unrecognized driver of evolution in both predators and prey. © 2011 Blackwell Publishing Ltd.

Acoustic and electromagnetic emission as a tool for crack localization

International Nuclear Information System (INIS)

Sedlak, P; Sikula, J; Lokajicek, T; Mori, Y

2008-01-01

The creation of cracks is accompanied by electric charge redistribution due to loosened chemical bounds. Electric charge on a crack wall creates dipole moments. Vibrations of crack walls produce time-dependent dipole moments and, consequently, electric and magnetic fields are generated. An electric signal is induced on metal electrodes. Simultaneously with the electromagnetic emission (EME) signal, an acoustic emission (AE) signal is generated, but due to the different velocities of propagation of both waves, the detection of the AE signal is delayed. This time delay presents the time of the wave propagation from the individual acoustic emission sensor to the crack. The defect can be located by means of these time intervals. This paper describes the localization using acoustic and electromagnetic emission signals for the two-dimensional case

Male Diaphorina citri searching responses to vibrational communication signals

Science.gov (United States)

Prototype devices have been developed that mimic D. citri female replies to male communication signals and lure males to a trap. The objective is to trap a high proportion of males that have landed on a host tree and have begun searching for females. This presentation describes the construction and ...

Intercellular signal communication among odontoblasts and trigeminal ganglion neurons via glutamate.

Science.gov (United States)

Nishiyama, A; Sato, M; Kimura, M; Katakura, A; Tazaki, M; Shibukawa, Y

2016-11-01

Various stimuli to the exposed surface of dentin induce changes in the hydrodynamic force inside the dentinal tubules resulting in dentinal pain. Recent evidences indicate that mechano-sensor channels, such as the transient receptor potential channels, in odontoblasts receive these hydrodynamic forces and trigger the release of ATP to the pulpal neurons, to generate dentinal pain. A recent study, however, has shown that odontoblasts also express glutamate receptors (GluRs). This implies that cells in the dental pulp tissue have the ability to release glutamate, which acts as a functional intercellular mediator to establish inter-odontoblast and odontoblast-trigeminal ganglion (TG) neuron signal communication. To investigate the intercellular signal communication, we applied mechanical stimulation to odontoblasts and measured the intracellular free Ca 2+ concentration ([Ca 2+ ] i ). During mechanical stimulation in the presence of extracellular Ca 2+ , we observed a transient [Ca 2+ ] i increase not only in single stimulated odontoblasts, but also in adjacent odontoblasts. We could not observe these responses in the absence of extracellular Ca 2+ . [Ca 2+ ] i increases in the neighboring odontoblasts during mechanical stimulation of single odontoblasts were inhibited by antagonists of metabotropic glutamate receptors (mGluRs) as well as glutamate-permeable anion channels. In the odontoblast-TG neuron coculture, we observed an increase in [Ca 2+ ] i in the stimulated odontoblasts and TG neurons, in response to direct mechanical stimulation of single odontoblasts. These [Ca 2+ ] i increases in the neighboring TG neurons were inhibited by antagonists for mGluRs. The [Ca 2+ ] i increases in the stimulated odontoblasts were also inhibited by mGluRs antagonists. We further confirmed that the odontoblasts express group I, II, and III mGluRs. However, we could not record any currents evoked from odontoblasts near the mechanically stimulated odontoblast, with or without

Acoustic measuring techniques for suspended sediment

Science.gov (United States)

Gruber, P.; Felix, D.; Storti, G.; Lattuada, M.; Fleckenstein, P.; Deschwanden, F.

2016-11-01

Acoustic signals can be used in various ways for suspended sediment monitoring. One possibility which lends itself particularly well in the context of hydropower plants (HPPs), is to use installations for acoustic discharge measurement (ADM). Such installations already exist at waterways of many HPPs. Similar to certain turbidimeters, the attenuation of the forward scattered signal travelling through the water-sediment mixture is correlated with suspended sediment concentration (SSC). This correlation can be based on reference SSCs, e.g. from gravimetric analyses of bottle samples. Without the need of additional sensors and practically maintenance-free, this method is used successfully in the HPP Fieschertal to warn the HPP operator of high SSC to prevent excessive turbine abrasion. Acoustic methods and systems that allow for estimating both SSC and particle size distribution (PSD) are under development. The simultaneous determination of SSC and PSD is not possible using a single frequency. Therefore, multi-frequency approaches are investigated for generally scattered signals. When backscattered signals are used, a stronger frequency dependency can be exploited. However, the reliable simultaneous determination of particle size (and distribution) and concentration is still a major challenge due to a low signal-to-noise ratio and an ill- posed problem of estimating concentration and size from recorded signals. The optimal setup configuration (angles, frequencies) for such a system is not unique and further investigations are recommended.

Acoustic control of sodium leakage in valve gates of NPP

International Nuclear Information System (INIS)

Trykov, E.L.; Kovtun, S.N.; Anan'ev, A.A.; Yugov, S.I.

2014-01-01

Short description of sodium bench and acoustic investigation results on leakage monitoring of valves DN10 and DN40 are given. It is shown that acoustic method can be used successfully to control the leakages of sodium valves. Leakages on both type of valves increase the acoustic signal dispersion by 2-3 orders. For each type of valve acoustic system of leakage determination allows to conduct the preliminary graduation of signal dispersion on the sodium discharge rate. It make possible not only to record the leakage presence but also to determine the sodium discharge rate through the valve during the leakage [ru

Theoretical detection threshold of the proton-acoustic range verification technique

International Nuclear Information System (INIS)

Ahmad, Moiz; Yousefi, Siavash; Xing, Lei; Xiang, Liangzhong

2015-01-01

Purpose: Range verification in proton therapy using the proton-acoustic signal induced in the Bragg peak was investigated for typical clinical scenarios. The signal generation and detection processes were simulated in order to determine the signal-to-noise limits. Methods: An analytical model was used to calculate the dose distribution and local pressure rise (per proton) for beams of different energy (100 and 160 MeV) and spot widths (1, 5, and 10 mm) in a water phantom. In this method, the acoustic waves propagating from the Bragg peak were generated by the general 3D pressure wave equation implemented using a finite element method. Various beam pulse widths (0.1–10 μs) were simulated by convolving the acoustic waves with Gaussian kernels. A realistic PZT ultrasound transducer (5 cm diameter) was simulated with a Butterworth bandpass filter with consideration of random noise based on a model of thermal noise in the transducer. The signal-to-noise ratio on a per-proton basis was calculated, determining the minimum number of protons required to generate a detectable pulse. The maximum spatial resolution of the proton-acoustic imaging modality was also estimated from the signal spectrum. Results: The calculated noise in the transducer was 12–28 mPa, depending on the transducer central frequency (70–380 kHz). The minimum number of protons detectable by the technique was on the order of 3–30 × 10 6 per pulse, with 30–800 mGy dose per pulse at the Bragg peak. Wider pulses produced signal with lower acoustic frequencies, with 10 μs pulses producing signals with frequency less than 100 kHz. Conclusions: The proton-acoustic process was simulated using a realistic model and the minimal detection limit was established for proton-acoustic range validation. These limits correspond to a best case scenario with a single large detector with no losses and detector thermal noise as the sensitivity limiting factor. Our study indicated practical proton-acoustic range

Theoretical detection threshold of the proton-acoustic range verification technique

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Moiz; Yousefi, Siavash; Xing, Lei, E-mail: lei@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305-5847 (United States); Xiang, Liangzhong [Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019-1101 (United States)

2015-10-15

Purpose: Range verification in proton therapy using the proton-acoustic signal induced in the Bragg peak was investigated for typical clinical scenarios. The signal generation and detection processes were simulated in order to determine the signal-to-noise limits. Methods: An analytical model was used to calculate the dose distribution and local pressure rise (per proton) for beams of different energy (100 and 160 MeV) and spot widths (1, 5, and 10 mm) in a water phantom. In this method, the acoustic waves propagating from the Bragg peak were generated by the general 3D pressure wave equation implemented using a finite element method. Various beam pulse widths (0.1–10 μs) were simulated by convolving the acoustic waves with Gaussian kernels. A realistic PZT ultrasound transducer (5 cm diameter) was simulated with a Butterworth bandpass filter with consideration of random noise based on a model of thermal noise in the transducer. The signal-to-noise ratio on a per-proton basis was calculated, determining the minimum number of protons required to generate a detectable pulse. The maximum spatial resolution of the proton-acoustic imaging modality was also estimated from the signal spectrum. Results: The calculated noise in the transducer was 12–28 mPa, depending on the transducer central frequency (70–380 kHz). The minimum number of protons detectable by the technique was on the order of 3–30 × 10{sup 6} per pulse, with 30–800 mGy dose per pulse at the Bragg peak. Wider pulses produced signal with lower acoustic frequencies, with 10 μs pulses producing signals with frequency less than 100 kHz. Conclusions: The proton-acoustic process was simulated using a realistic model and the minimal detection limit was established for proton-acoustic range validation. These limits correspond to a best case scenario with a single large detector with no losses and detector thermal noise as the sensitivity limiting factor. Our study indicated practical proton-acoustic

Distributed acoustic sensing with Michelson interferometer demodulation

Science.gov (United States)

Liu, Xiaohui; Wang, Chen; Shang, Ying; Wang, Chang; Zhao, Wenan; Peng, Gangding; Wang, Hongzhong

2017-09-01

The distributed acoustic sensing (DAS) has been extensively studied and widely used. A distributed acoustic sensing system based on the unbalanced Michelson interferometer with phase generated carrier (PGC) demodulation was designed and tested. The system could directly obtain the phase, amplitude, frequency response, and location information of sound wave at the same time and measurement at all points along the sensing fiber simultaneously. Experiments showed that the system successfully measured the acoustic signals with a phase-pressure sensitivity about-148 dB (re rad/μPa) and frequency response ripple less than 1.5 dB. The further field experiment showed that the system could measure signals at all points along the sensing fiber simultaneously.

Nondestructive online testing method for friction stir welding using acoustic emission

Science.gov (United States)

Levikhina, Anastasiya

2017-12-01

The paper reviews the possibility of applying the method of acoustic emission for online monitoring of the friction stir welding process. It is shown that acoustic emission allows the detection of weld defects and their location in real time. The energy of an acoustic signal and the median frequency are suggested to be used as informative parameters. The method of calculating the median frequency with the use of a short time Fourier transform is applied for the identification of correlations between the defective weld structure and properties of the acoustic emission signals received during welding.

iSAT: The Integrated Satellite and Acoustic Telemetry system for tracking marine megafauna

KAUST Repository

De La Torre, Pedro R.

2014-05-01

In this dissertation an innovative technology to study whale sharks, Rhincodon typus is presented. The Integrated Satellite and Acoustic Telemetry project (iSAT) combines underwater acoustic telemetry, autonomous navigation and radio frequency communications into a standalone system. The whale shark, a resident of the Saudi Arabian Red Sea, is the target of the study. The technology presented is designed to help close current gaps in the knowledge of whale shark biology; these are gaps that prohibit the design of optimal conservation strategies. Unfortunately, the various existing tracking technologies each have limitations and are unable to solve all the unanswered questions. Whale shark populations are increasingly threatened by anthropogenic activities such as targeted and indirect fishing pressure, creating an urgent need for better management practices. This dissertation addresses the current state-of-the-art of relevant technologies, including autonomous surface vehicles (ASVs), sensors for research in the ocean and remote monitoring of wild fauna (biotelemetry). iSAT contains components of all of these technologies, but the primary achievement of this dissertation is the development of iSAT’s Acoustic Tracking System (ATS). Underwater, the most efficient way of transmitting energy through long distances is sound. An electronic tag is attached to an animal and works as its acoustic identifier. iSAT’s hydrophone array detects the presence and direction of the acoustic signal generated by the tag. The expected performance, range, and capacity to tell the direction to the tag are explained and compared to the actual measured values. The first operational iSAT ATS is demonstrated. This work represents significant advancement towards a fully autonomous iSAT system. Developments on the power electronics, navigation, renewable energy harvesting, and other modules are included in this research. With the recent integration of digital acquisition systems, i

Experimental Acoustic Evaluation of an Auditorium

Directory of Open Access Journals (Sweden)

Marina Dana Ţopa

2012-01-01

Full Text Available The paper presents a case history: the acoustical analysis of a rectangular auditorium. The following acoustical parameters were evaluated: early decay time, reverberation time, clarity, definition, and center time. The excitation signal was linear sweep sine and additional analysis was carried out: peak-to-noise ratio, reverberation time for empty and occupied room, standard deviation of acoustical parameters, diffusion, and just noticeable differences analysis. Conclusions about room’s destination and modeling were drawn in the end.

Influence of multi-microphone signal enhancement algorithms on auditory movement detection in acoustically complex situations

DEFF Research Database (Denmark)

Lundbeck, Micha; Hartog, Laura; Grimm, Giso

2017-01-01

The influence of hearing aid (HA) signal processing on the perception of spatially dynamic sounds has not been systematically investigated so far. Previously, we observed that interfering sounds impaired the detectability of left-right source movements and reverberation that of near-far source...... movements for elderly hearing-impaired (EHI) listeners (Lundbeck et al., 2017). Here, we explored potential ways of improving these deficits with HAs. To that end, we carried out acoustic analyses to examine the impact of two beamforming algorithms and a binaural coherence-based noise reduction scheme...... on the cues underlying movement perception. While binaural cues remained mostly unchanged, there were greater monaural spectral changes and increases in signal-to-noise ratio and direct-to-reverberant sound ratio as a result of the applied processing. Based on these findings, we conducted a listening test...

Multipoint dynamically reconfigure adaptive distributed fiber optic acoustic emission sensor (FAESense) system for condition based maintenance

Science.gov (United States)

Mendoza, Edgar; Prohaska, John; Kempen, Connie; Esterkin, Yan; Sun, Sunjian; Krishnaswamy, Sridhar

2010-09-01

This paper describes preliminary results obtained under a Navy SBIR contract by Redondo Optics Inc. (ROI), in collaboration with Northwestern University towards the development and demonstration of a next generation, stand-alone and fully integrated, dynamically reconfigurable, adaptive fiber optic acoustic emission sensor (FAESense™) system for the in-situ unattended detection and localization of shock events, impact damage, cracks, voids, and delaminations in new and aging critical infrastructures found in ships, submarines, aircraft, and in next generation weapon systems. ROI's FAESense™ system is based on the integration of proven state-of-the-art technologies: 1) distributed array of in-line fiber Bragg gratings (FBGs) sensors sensitive to strain, vibration, and acoustic emissions, 2) adaptive spectral demodulation of FBG sensor dynamic signals using two-wave mixing interferometry on photorefractive semiconductors, and 3) integration of all the sensor system passive and active optoelectronic components within a 0.5-cm x 1-cm photonic integrated circuit microchip. The adaptive TWM demodulation methodology allows the measurement of dynamic high frequnency acoustic emission events, while compensating for passive quasi-static strain and temperature drifts. It features a compact, low power, environmentally robust 1-inch x 1-inch x 4-inch small form factor (SFF) package with no moving parts. The FAESense™ interrogation system is microprocessor-controlled using high data rate signal processing electronics for the FBG sensors calibration, temperature compensation and the detection and analysis of acoustic emission signals. Its miniaturized package, low power operation, state-of-the-art data communications, and low cost makes it a very attractive solution for a large number of applications in naval and maritime industries, aerospace, civil structures, the oil and chemical industry, and for homeland security applications.

Modeling the complexity of acoustic emission during intermittent plastic deformation: Power laws and multifractal spectra.

Science.gov (United States)

Kumar, Jagadish; Ananthakrishna, G

2018-01-01

Scale-invariant power-law distributions for acoustic emission signals are ubiquitous in several plastically deforming materials. However, power-law distributions for acoustic emission energies are reported in distinctly different plastically deforming situations such as hcp and fcc single and polycrystalline samples exhibiting smooth stress-strain curves and in dilute metallic alloys exhibiting discontinuous flow. This is surprising since the underlying dislocation mechanisms in these two types of deformations are very different. So far, there have been no models that predict the power-law statistics for discontinuous flow. Furthermore, the statistics of the acoustic emission signals in jerky flow is even more complex, requiring multifractal measures for a proper characterization. There has been no model that explains the complex statistics either. Here we address the problem of statistical characterization of the acoustic emission signals associated with the three types of the Portevin-Le Chatelier bands. Following our recently proposed general framework for calculating acoustic emission, we set up a wave equation for the elastic degrees of freedom with a plastic strain rate as a source term. The energy dissipated during acoustic emission is represented by the Rayleigh-dissipation function. Using the plastic strain rate obtained from the Ananthakrishna model for the Portevin-Le Chatelier effect, we compute the acoustic emission signals associated with the three Portevin-Le Chatelier bands and the Lüders-like band. The so-calculated acoustic emission signals are used for further statistical characterization. Our results show that the model predicts power-law statistics for all the acoustic emission signals associated with the three types of Portevin-Le Chatelier bands with the exponent values increasing with increasing strain rate. The calculated multifractal spectra corresponding to the acoustic emission signals associated with the three band types have a maximum

The Simplest Demonstration on Acoustic Beats

Science.gov (United States)

Ganci, Alessio; Ganci, Salvatore

2015-01-01

The classical demonstration experiment on acoustic beats using two signal generators and a dual trace oscilloscope is an important ingredient in teaching the subject. This short laboratory note aims to point out what may be the simplest demonstrative experiment on acoustic beats to carry out in a classroom without employing any lab apparatus.

Method and system for generating a beam of acoustic energy from a borehole, and applications thereof

Science.gov (United States)

Johnson, Paul A [Santa Fe, NM; Ten Cate, James A [Los Alamos, NM; Guyer, Robert [Reno, NV; Le Bas, Pierre-Yves [Los Alamos, NM; Vu, Cung [Houston, TX; Nihei, Kurt [Oakland, CA; Schmitt, Denis P [Katy, TX; Skelt, Christopher [Houston, TX

2012-02-14

A compact array of transducers is employed as a downhole instrument for acoustic investigation of the surrounding rock formation. The array is operable to generate simultaneously a first acoustic beam signal at a first frequency and a second acoustic beam signal at a second frequency different than the first frequency. These two signals can be oriented through an azimuthal rotation of the array and an inclination rotation using control of the relative phases of the signals from the transmitter elements or electromechanical linkage. Due to the non-linearity of the formation, the first and the second acoustic beam signal mix into the rock formation where they combine into a collimated third signal that propagates in the formation along the same direction than the first and second signals and has a frequency equal to the difference of the first and the second acoustic signals. The third signal is received either within the same borehole, after reflection, or another borehole, after transmission, and analyzed to determine information about rock formation. Recording of the third signal generated along several azimuthal and inclination directions also provides 3D images of the formation, information about 3D distribution of rock formation and fluid properties and an indication of the dynamic acoustic non-linearity of the formation.

Digital nonlinearity compensation in high-capacity optical communication systems considering signal spectral broadening effect.

Science.gov (United States)

Xu, Tianhua; Karanov, Boris; Shevchenko, Nikita A; Lavery, Domaniç; Liga, Gabriele; Killey, Robert I; Bayvel, Polina

2017-10-11

Nyquist-spaced transmission and digital signal processing have proved effective in maximising the spectral efficiency and reach of optical communication systems. In these systems, Kerr nonlinearity determines the performance limits, and leads to spectral broadening of the signals propagating in the fibre. Although digital nonlinearity compensation was validated to be promising for mitigating Kerr nonlinearities, the impact of spectral broadening on nonlinearity compensation has never been quantified. In this paper, the performance of multi-channel digital back-propagation (MC-DBP) for compensating fibre nonlinearities in Nyquist-spaced optical communication systems is investigated, when the effect of signal spectral broadening is considered. It is found that accounting for the spectral broadening effect is crucial for achieving the best performance of DBP in both single-channel and multi-channel communication systems, independent of modulation formats used. For multi-channel systems, the degradation of DBP performance due to neglecting the spectral broadening effect in the compensation is more significant for outer channels. Our work also quantified the minimum bandwidths of optical receivers and signal processing devices to ensure the optimal compensation of deterministic nonlinear distortions.

Wireless acoustic-electric feed-through for power and signal transmission

Science.gov (United States)

Doty, Benjamin (Inventor); Badescu, Mircea (Inventor); Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor); Bar-Cohen, Yoseph (Inventor); Chang, Zensheu (Inventor)

2011-01-01

An embodiment provides electrical energy from a source on one side of a medium to a load on the other side of the medium, the embodiment including a first piezoelectric to generate acoustic energy in response to electrical energy from the source, and a second piezoelectric to convert the received acoustic energy to electrical energy used by the load. Other embodiments are described and claimed.

Signal processing techniques for the acoustic detection of boiling in LMFBRs: preliminary results of an IAEA collaborative research programme

International Nuclear Information System (INIS)

Macleod, I.D.

1988-01-01

A specialist meeting organised by the International Working Group on Fast Reactors (IWGFR) of the International Atomic Energy Agency (IAEA) was held at Chester in the United Kingdom in 1981 to discuss techniques for the detection of acoustic noise from boiling. This meeting recommended that a benchmark test should be carried out to evaluate and compare signal processing methods for use in the detection of the acoustic noise produced by boiling sodium. In response to this recommendation the IAEA set up a collaborative research programme to examine and compare the processing techniques used in the laboratories of member countries. Eight laboratories in six countries have taken part in the programme which will be completed in 1988. This paper summarises the results obtained so far. (author)

Fatigue characteristics of high strength fire resistance steel for frame structure and time-frequency analysis its acoustic emission signal

International Nuclear Information System (INIS)

Kim, Hyun Soo; Nam, Ki Woo; Kang, Chang Young

2000-01-01

Demand for now nondestructive evaluation are growing to detect fatigue crack growth behavior to predict long term performance of materials and structure in aggressive environments, especially when they are in non-visible area. Acoustic emission technique is well suited to these problems and has drawn a keen interests because of its dynamic detection ability, extreme sensitivity and location of growing defects. In this study, we analysed acoustic emission signals obtained in fatigue and tensile test of high strength fire resistance steel for frame structure with time-frequency analysis methods. The main frequency range is different in the noise and the fatigue crack propagation. It could be classified that it were also generated by composite fracture mechanics of cleavage, dimple, inclusion separation etc

Acoustical Environment of Three Stations at Rileys Hump

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Passive acoustic recorders were deployed to record acoustic signals over the time span of two years, and the data analyzed for the existence of known spawning sounds...

Acoustic concentration of particles in fluid flow

Science.gov (United States)

Ward, Michael D.; Kaduchak, Gregory

2010-11-23

An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.

Acoustic concentration of particles in fluid flow

Science.gov (United States)

Ward, Michael W.; Kaduchak, Gregory

2017-08-15

Disclosed herein is a acoustic concentration of particles in a fluid flow that includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.

Acoustics aspects of technological process in the rock disintegration

Directory of Open Access Journals (Sweden)

Jozef Futó

2007-04-01

Full Text Available The paper describes some results of monitoring and aspects of the acoustic signal in the rock disintegration on the drillig stand of the Institute of Geotechnics, SAS in Košice. The registration and processing of the acoustic signal is solved as a part of the research grant task within the basic research of the rock disintegration by drilling.

Modulation Classification of Satellite Communication Signals Using Cumulants and Neural Networks

Science.gov (United States)

Smith, Aaron; Evans, Michael; Downey, Joseph

2017-01-01

National Aeronautics and Space Administration (NASA)'s future communication architecture is evaluating cognitive technologies and increased system intelligence. These technologies are expected to reduce the operational complexity of the network, increase science data return, and reduce interference to self and others. In order to increase situational awareness, signal classification algorithms could be applied to identify users and distinguish sources of interference. A significant amount of previous work has been done in the area of automatic signal classification for military and commercial applications. As a preliminary step, we seek to develop a system with the ability to discern signals typically encountered in satellite communication. Proposed is an automatic modulation classifier which utilizes higher order statistics (cumulants) and an estimate of the signal-to-noise ratio. These features are extracted from baseband symbols and then processed by a neural network for classification. The modulation types considered are phase-shift keying (PSK), amplitude and phase-shift keying (APSK),and quadrature amplitude modulation (QAM). Physical layer properties specific to the Digital Video Broadcasting - Satellite- Second Generation (DVB-S2) standard, such as pilots and variable ring ratios, are also considered. This paper will provide simulation results of a candidate modulation classifier, and performance will be evaluated over a range of signal-to-noise ratios, frequency offsets, and nonlinear amplifier distortions.

Remote listening and passive acoustic detection in a 3-D environment

Science.gov (United States)

Barnhill, Colin

Teleconferencing environments are a necessity in business, education and personal communication. They allow for the communication of information to remote locations without the need for travel and the necessary time and expense required for that travel. Visual information can be communicated using cameras and monitors. The advantage of visual communication is that an image can capture multiple objects and convey them, using a monitor, to a large group of people regardless of the receiver's location. This is not the case for audio. Currently, most experimental teleconferencing systems' audio is based on stereo recording and reproduction techniques. The problem with this solution is that it is only effective for one or two receivers. To accurately capture a sound environment consisting of multiple sources and to recreate that for a group of people is an unsolved problem. This work will focus on new methods of multiple source 3-D environment sound capture and applications using these captured environments. Using spherical microphone arrays, it is now possible to capture a true 3-D environment A spherical harmonic transform on the array's surface allows us to determine the basis functions (spherical harmonics) for all spherical wave solutions (up to a fixed order). This spherical harmonic decomposition (SHD) allows us to not only look at the time and frequency characteristics of an audio signal but also the spatial characteristics of an audio signal. In this way, a spherical harmonic transform is analogous to a Fourier transform in that a Fourier transform transforms a signal into the frequency domain and a spherical harmonic transform transforms a signal into the spatial domain. The SHD also decouples the input signals from the microphone locations. Using the SHD of a soundfield, new algorithms are available for remote listening, acoustic detection, and signal enhancement The new algorithms presented in this paper show distinct advantages over previous detection and

The record of electrical and communication engineering conversazione Tohoku University Volume 63, No. 3

Science.gov (United States)

1995-05-01

English abstracts contained are from papers authored by the research staff of the Research Institute of Electrical Communication and the departments of Electrical Engineering, Electrical Communications, Electronic Engineering, and Information Engineering, Tohoku University, which originally appeared in scientific journals in 1994. The abstracts are organized under the following disciplines: electromagnetic theory; physics; fundamental theory of information; communication theory and systems; signal and image processing; systems control; computers; artificial intelligence; recording; acoustics and speech; ultrasonic electronics; antenna, propagation, and transmission; optoelectronics and optical communications; quantum electronics; superconducting materials and applications; magnetic materials and magnetics; semiconductors; electronic materials and parts; electronic devices and integrated circuits; electronic circuits; medical electronics and bionics; measurements and applied electronics; electric power; and miscellaneous.

Signal Processing of Underwater Acoustic Waves

Science.gov (United States)

1969-11-01

for the interest they have shown in the work and for many helpful discussions. The book was supported by Naval Ship Systems Corn- mand tinder ...inclination of the ray. The relationship is such that for the maximum values of dnldz just quoted radius of 0ectromapnetic ray 2,0 radius of acoustic... relationship for the angles, in, of the geometric ray, and carry out the limiting process as h -- 0. Show that when the velocity func- tion c(z) is

Systematic Error of Acoustic Particle Image Velocimetry and Its Correction

Directory of Open Access Journals (Sweden)

Mickiewicz Witold

2014-08-01

Full Text Available Particle Image Velocimetry is getting more and more often the method of choice not only for visualization of turbulent mass flows in fluid mechanics, but also in linear and non-linear acoustics for non-intrusive visualization of acoustic particle velocity. Particle Image Velocimetry with low sampling rate (about 15Hz can be applied to visualize the acoustic field using the acquisition synchronized to the excitation signal. Such phase-locked PIV technique is described and used in experiments presented in the paper. The main goal of research was to propose a model of PIV systematic error due to non-zero time interval between acquisitions of two images of the examined sound field seeded with tracer particles, what affects the measurement of complex acoustic signals. Usefulness of the presented model is confirmed experimentally. The correction procedure, based on the proposed model, applied to measurement data increases the accuracy of acoustic particle velocity field visualization and creates new possibilities in observation of sound fields excited with multi-tonal or band-limited noise signals.

Acoustic Emission from Elevator Wire Ropes During Tensile Testing

Science.gov (United States)

Bai, Wenjie; Chai, Mengyu; Li, Lichan; Li, Yongquan; Duan, Quan

The acoustic emission (AE) technique was used to monitor the tensile testing process for two kinds of elevator wire ropes in our work. The AE signals from wire breaks were obtained and analyzed by AE parameters and waveforms. The results showed that AE technique can be a useful tool to monitor wire break phenomenon of wire ropes and effectively capture information of wire break signal. The relationship between AE signal characteristics and wire breaks is investigated and it is found that the most effective acoustic signal discriminators are amplitude and absolute energy. Moreover, the wire break signal of two kinds of ropes is a type of burst signal and it is believed that the waveform and spectrum can be applied to analyze the AE wire break signals.

A New Acoustic Emission Sensor Based Gear Fault Detection Approach

Directory of Open Access Journals (Sweden)

Junda Zhu

2013-01-01

Full Text Available In order to reduce wind energy costs, prognostics and health management (PHM of wind turbine is needed to ensure the reliability and availability of wind turbines. A gearbox is an important component of a wind turbine. Therefore, developing effective gearbox fault detection tools is important to the PHM of wind turbine. In this paper, a new acoustic emission (AE sensor based gear fault detection approach is presented. This approach combines a heterodyne based frequency reduction technique with time synchronous average (TSA and spectrum kurtosis (SK to process AE sensor signals and extract features as condition indictors for gear fault detection. Heterodyne technique commonly used in communication is first employed to preprocess the AE signals before sampling. By heterodyning, the AE signal frequency is down shifted from several hundred kHz to below 50 kHz. This reduced AE signal sampling rate is comparable to that of vibration signals. The presented approach is validated using seeded gear tooth crack fault tests on a notational split torque gearbox. The approach presented in this paper is physics based and the validation results have showed that it could effectively detect the gear faults.

The tradeoff between signal detection and recognition rules auditory sensitivity under variable background noise conditions.

Science.gov (United States)

Lugli, Marco

2015-12-07

Animal acoustic communication commonly takes place under masked conditions. For instance, sound signals relevant for mating and survival are very often masked by background noise, which makes their detection and recognition by organisms difficult. Ambient noise (AN) varies in level and shape among different habitats, but also remarkable variations in time and space occurs within the same habitat. Variable AN conditions mask hearing thresholds of the receiver in complex and unpredictable ways, thereby causing distortions in sound perception. When communication takes place in a noisy environment, a highly sensitive system might confer no advantage to the receiver compared to a less sensitive one. The effects of noise masking on auditory thresholds and hearing-related functions are well known, and the potential role of AN in the evolution of the species' auditory sensitivity has been recognized by few authors. The mechanism of the underlying selection process has never been explored, however. Here I present a simple fitness model that seeks for the best sensitivity of a hearing system performing the detection and recognition of the sound under variable AN conditions. The model predicts higher sensitivity (i.e. lower hearing thresholds) as best strategy for species living in quiet habitats and lower sensitivity (i.e. higher hearing thresholds) as best strategy for those living in noisy habitats provided the cost of incorrect recognition is not low. The tradeoff between detection and recognition of acoustic signals appears to be a key factor determining the best level of hearing sensitivity of a species when acoustic communication is corrupted by noise. Copyright © 2015 Elsevier Ltd. All rights reserved.

Practical acoustic emission testing

CERN Document Server

2016-01-01

This book is intended for non-destructive testing (NDT) technicians who want to learn practical acoustic emission testing based on level 1 of ISO 9712 (Non-destructive testing – Qualification and certification of personnel) criteria. The essential aspects of ISO/DIS 18436-6 (Condition monitoring and diagnostics of machines – Requirements for training and certification of personnel, Part 6: Acoustic Emission) are explained, and readers can deepen their understanding with the help of practice exercises. This work presents the guiding principles of acoustic emission measurement, signal processing, algorithms for source location, measurement devices, applicability of testing methods, and measurement cases to support not only researchers in this field but also and especially NDT technicians.

Acoustic biosensors.

Science.gov (United States)

Fogel, Ronen; Limson, Janice; Seshia, Ashwin A

2016-06-30

Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Recent experiments on acoustic leak detection

International Nuclear Information System (INIS)

Voss, J.; Arnaoutis, N.

1984-01-01

In the ASB-sodium loop a series of injection experiments with water, helium, argon and nitrogen was performed. The aim of these tests was to get: a comparison of the acoustic signals, generated by water and gas injections with regard to intensity and frequency content; an experimental basis for the design of an acoustic calibration source. The experimental set-up, the variation parameters and first results will be discussed. The principal design of an acoustic calibration source and its range of application will be given. (author)

Measuring procedure of experimental data acquisition and data evaluation of acoustic emission in rock disintegration

Directory of Open Access Journals (Sweden)

Lucia Ivaničová

2009-12-01

Full Text Available The paper describes the results of measurements of acoustic signal arising in rock disintegration on the drilling standof the Institute of Geotechnics SAS in Košice. The acoustic signal was registered with sonometer Mediator 2238. Registrationand processing of the acoustic signal is solved as a part of the research grant task within the basic research of the rock disintegrationby drilling.

Fractal Communication System Using Digital Signal Processing Starter Kit (DSK TMS320c6713

Directory of Open Access Journals (Sweden)

Arsyad Ramadhan Darlis

2015-12-01

Full Text Available In 1992, Wornell and Oppenheim did research on a modulation which is formed by using wavelet theory. In some other studies, proved that this modulation can survive on a few channels and has reliability in some applications. Because of this modulation using the concept of fractal, then it is called as fractalmodulation. Fractal modulation is formed by inserting information signal into fractal signals that are selffractal similary. This modulation technique has the potential to replace the OFDM (Orthogonal Frequency Division Multiplexing, which is currently used on some of the latest telecommunication technologies. The purpose of this research is to implement the fractal communication system using Digital Signal Processing Starter Kit (DSK TMS320C6713 without using AWGN and Rayleigh channel in order to obtain the ideal performance of the system. From the simulation results using MATLAB7.4. it appears that this communication system has good performance on some channels than any other communication systems. While in terms of implementation by using (DSK via TMS320C6713 Code Composer Studio (CCS, it can be concluded that thefractal communication system has a better execution time on some tests.

Acoustic Emission Stethoscope - Measurements with Acoustic Emission on Wind Turbines

Energy Technology Data Exchange (ETDEWEB)

Krystof Kryniski [AaF Infrastructure, Stockholm (Sweden)

2013-02-15

A remote ultrasonic stethoscope, designed on mobile devices to help a maintenance team in diagnosing drive train problems, has been demonstrated. By implementing an acoustic emission technology, the operating conditions of wind turbines have been assessed by trending techniques and ultrasonic acoustic emission converted into audible sound. The new approach has been developed and tested and compared to other monitoring techniques. Acoustic emission has generally been shown to provide a number of advantages over vibration and shock pulse methods because the system is operating in a substantially higher frequency range (100 kHz) and therefore it is more immune to operation of surrounding machines and components. Quick attenuation of ultrasonic propagation waves in the drive-train structure helps to pin-point the origin of any fault as the signals are sharper and more pronounced. Further, with the intensity measurements a direction of the source of ultrasonic energy can be identified. Using a high frequency thus makes the method suitable for measuring local effects and to determine local defects since the disturbing signals from other parts are damped. Recently developed programmable sensors capable of processing signals onboard, producing quality outputs with extremely low noise-to-signal ratio, have been used. It is discussed how the new approach can lower the cost of a wind-turbine monitoring system, while at the same time making it simple and more reliable, see Appendix A. The method has been tested on rotating parts of wind-turbines, including traditionally difficult areas such as low speed main bearings and planetary gearboxes. The method developed in the project was designed to see physical processes such as friction, impacts and metal removal, occurring when machinery degrades, can be detected and notified with the developed notification system. Apart from reporting the status and displaying the changes of the pre-defined parameters or symptoms, the system has

Removing Background Noise with Phased Array Signal Processing

Science.gov (United States)

Podboy, Gary; Stephens, David

2015-01-01

Preliminary results are presented from a test conducted to determine how well microphone phased array processing software could pull an acoustic signal out of background noise. The array consisted of 24 microphones in an aerodynamic fairing designed to be mounted in-flow. The processing was conducted using Functional Beam forming software developed by Optinav combined with cross spectral matrix subtraction. The test was conducted in the free-jet of the Nozzle Acoustic Test Rig at NASA GRC. The background noise was produced by the interaction of the free-jet flow with the solid surfaces in the flow. The acoustic signals were produced by acoustic drivers. The results show that the phased array processing was able to pull the acoustic signal out of the background noise provided the signal was no more than 20 dB below the background noise level measured using a conventional single microphone equipped with an aerodynamic forebody.

Secure communications of CAP-4 and OOK signals over MMF based on electro-optic chaos.

Science.gov (United States)

Ai, Jianzhou; Wang, Lulu; Wang, Jian

2017-09-15

Chaos-based secure communication can provide a high level of privacy in data transmission. Here, we experimentally demonstrate secure signal transmission over two kinds of multimode fiber (MMF) based on electro-optic intensity chaos. High-quality synchronization is achieved in an electro-optic feedback configuration. Both 5  Gbit/s carrier-less amplitude/phase (CAP-4) modulation and 10  Gbit/s on-off key (OOK) signals are recovered efficiently in electro-optic chaos-based communication systems. Degradations of chaos synchronization and communication system due to mismatch of various hardware keys are also discussed.

International Conference on VLSI, Communication, Advanced Devices, Signals & Systems and Networking

CERN Document Server

Shirur, Yasha; Prasad, Rekha

2013-01-01

This book is a collection of papers presented by renowned researchers, keynote speakers and academicians in the International Conference on VLSI, Communication, Analog Designs, Signals and Systems, and Networking (VCASAN-2013), organized by B.N.M. Institute of Technology, Bangalore, India during July 17-19, 2013. The book provides global trends in cutting-edge technologies in electronics and communication engineering. The content of the book is useful to engineers, researchers and academicians as well as industry professionals.

Vibro-acoustic modulation–based damage identification in a composite skin–stiffener structure

NARCIS (Netherlands)

Ooijevaar, T.H.; Rogge, M.D.; Loendersloot, Richard; Warnet, Laurent; Akkerman, Remko; Tinga, Tiedo

2016-01-01

Vibro-acoustic modulation–based damage identification relies on the modulation of a high-frequency carrier signal by an intenser low-frequency vibration signal due to damage-induced structural nonlinearities. A time domain analysis of the vibro-acoustic modulation phenomena was presented at multiple

Systems and methods for biometric identification using the acoustic properties of the ear canal

International Nuclear Information System (INIS)

Bouchard, A.M.; Osbourn, G.C.

1998-01-01

The present invention teaches systems and methods for verifying or recognizing a person's identity based on measurements of the acoustic response of the individual's ear canal. The system comprises an acoustic emission device, which emits an acoustic source signal s(t), designated by a computer, into the ear canal of an individual, and an acoustic response detection device, which detects the acoustic response signal f(t). A computer digitizes the response (detected) signal f(t) and stores the data. Computer-implemented algorithms analyze the response signal f(t) to produce ear-canal feature data. The ear-canal feature data obtained during enrollment is stored on the computer, or some other recording medium, to compare the enrollment data with ear-canal feature data produced in a subsequent access attempt, to determine if the individual has previously been enrolled. The system can also be adapted for remote access applications. 5 figs

Systems and methods for biometric identification using the acoustic properties of the ear canal

Science.gov (United States)

Bouchard, Ann Marie; Osbourn, Gordon Cecil

1998-01-01

The present invention teaches systems and methods for verifying or recognizing a person's identity based on measurements of the acoustic response of the individual's ear canal. The system comprises an acoustic emission device, which emits an acoustic source signal s(t), designated by a computer, into the ear canal of an individual, and an acoustic response detection device, which detects the acoustic response signal f(t). A computer digitizes the response (detected) signal f(t) and stores the data. Computer-implemented algorithms analyze the response signal f(t) to produce ear-canal feature data. The ear-canal feature data obtained during enrollment is stored on the computer, or some other recording medium, to compare the enrollment data with ear-canal feature data produced in a subsequent access attempt, to determine if the individual has previously been enrolled. The system can also be adapted for remote access applications.

Acoustic emission measurement during instrumented impact tests

International Nuclear Information System (INIS)

Crostack, H.A.; Engelhardt, A.H.

1983-01-01

Results of instrumented impact tests are discussed. On the one hand the development of the loading process at the hammer tup was recorded by means of a piezoelectric transducer. This instrumentation supplied a better representation of the load versus time than the conventional strain gauges. On the other hand the different types of acoustic emission occurring during a test could be separated. The acoustic emission released at the impact of the hammer onto the specimen is of lower frequency and its spectrum is strongly decreasing with increasing frequency. Plastic deformation also emits signals of lower frequency that are of quasi-continuous character. Both signal types can be discriminated by filtering. As a consequence typical burst signal were received afterwards that can be correlated with crack propagation. Their spectra exhibit considerable portions up to about 1.9 MHz. The development in time of the burst signals points to the kind of crack propagation resp. its sequence of appearance. However, definitive comparison between load and acoustic emission should become possible, only when the disadvantages of the common load measurement can be reduced, e.g. by determining the load directly at the specimen instead of the hammer tup

Analysis of acoustic emission signals at austempering of steels using neural networks

Science.gov (United States)

Łazarska, Malgorzata; Wozniak, Tadeusz Z.; Ranachowski, Zbigniew; Trafarski, Andrzej; Domek, Grzegorz

2017-05-01

Bearing steel 100CrMnSi6-4 and tool steel C105U were used to carry out this research with the steels being austempered to obtain a martensitic-bainitic structure. During the process quite a large number of acoustic emissions (AE) were observed. These signals were then analysed using neural networks resulting in the identification of three groups of events of: high, medium and low energy and in addition their spectral characteristics were plotted. The results were presented in the form of diagrams of AE incidence as a function of time. It was demonstrated that complex transformations of austenite into martensite and bainite occurred when austempering bearing steel at 160 °C and tool steel at 130 °C respectively. The selected temperatures of isothermal quenching of the tested steels were within the area near to MS temperature, which affected the complex course of phase transition. The high activity of AE is a typical occurrence for martensitic transformation and this is the transformation mechanism that induces the generation of AE signals of higher energy in the first stage of transition. In the second stage of transformation, the initially nucleated martensite accelerates the occurrence of the next bainitic transformation.

[Acoustic characteristics of adductor spasmodic dysphonia].

Science.gov (United States)

Yang, Yang; Wang, Li-Ping

2008-06-01

To explore the acoustic characteristics of adductor spasmodic dysphonia. The acoustic characteristics, including acoustic signal of recorded voice, three-dimensional sonogram patterns and subjective assessment of voice, between 10 patients (7 women, 3 men) with adductor spasmodic dysphonia and 10 healthy volunteers (5 women, 5 men), were compared. The main clinical manifestation of adductor spasmodic dysphonia included the disorders of sound quality, rhyme and fluency. It demonstrated the tension dysphonia when reading, acoustic jitter, momentary fluctuation of frequency and volume, voice squeezing, interruption, voice prolongation, and losing normal chime. Among 10 patients, there were 1 mild dysphonia (abnormal syllable number dysphonia (abnormal syllable number 25%-49%), 1 severe dysphonia (abnormal syllable number 50%-74%) and 2 extremely severe dysphonia (abnormal syllable number > or = 75%). The average reading time in 10 patients was 49 s, with reading time extension and aphasia area interruption in acoustic signals, whereas the average reading time in health control group was 30 s, without voice interruption. The aphasia ratio averaged 42%. The respective symptom syllable in different patients demonstrated in the three-dimensional sonogram. There were voice onset time prolongation, irregular, interrupted and even absent vowel formants. The consonant of symptom syllables displayed absence or prolongation of friction murmur in the block-friction murmur occasionally. The acoustic characteristics of adductor spasmodic dysphonia is the disorders of sound quality, rhyme and fluency. The three-dimensional sonogram of the symptom syllables show distinctive changes of proportional vowels or consonant phonemes.

Ambiguity of source location in acoustic emission technique

International Nuclear Information System (INIS)

Barat, P.; Mukherjee, P.; Kalyanasundaram, P.; Raj, B.

1996-01-01

Location of acoustic emission (AE) source in a plane is detected from the difference of the arrival times of the AE signal to at least three sensors placed on it. The detected location may not be unique in all cases. In this paper, the condition for the unambiguous solution for the location of the source has been deduced mathematically in terms of arrival times of the AE signal, the coordinate of the three sensors and the acoustic velocity. (author)

Acoustic waveform of continuous bubbling in a non-Newtonian fluid.

Science.gov (United States)

Vidal, Valérie; Ichihara, Mie; Ripepe, Maurizio; Kurita, Kei

2009-12-01

We study experimentally the acoustic signal associated with a continuous bubble bursting at the free surface of a non-Newtonian fluid. Due to the fluid rheological properties, the bubble shape is elongated, and, when bursting at the free surface, acts as a resonator. For a given fluid concentration, at constant flow rate, repetitive bubble bursting occurs at the surface. We report a modulation pattern of the acoustic waveform through time. Moreover, we point out the existence of a precursor acoustic signal, recorded on the microphone array, previous to each bursting. The time delay between this precursor and the bursting signal is well correlated with the bursting signal frequency content. Their joint modulation through time is driven by the fluid rheology, which strongly depends on the presence of small satellite bubbles trapped in the fluid due to the yield stress.

Digital Signal Processing for Optical Coherent Communication Systems

DEFF Research Database (Denmark)

Zhang, Xu

spectrum narrowing tolerance 112-Gb/s DP-QPSK optical coherent systems using digital adaptive equalizer. The demonstrated results show that off-line DSP algorithms are able to reduce the bit error rate (BER) penalty induced by signal spectrum narrowing. Third, we also investigate bi...... wavelength division multiplex (U-DWDM) optical coherent systems based on 10-Gbaud QPSK. We report U-DWDM 1.2-Tb/s QPSK coherent system achieving spectral efficiency of 4.0-bit/s/Hz. In the experimental demonstration, digital decision feed back equalizer (DFE) algorithms and a finite impulse response (FIR......In this thesis, digital signal processing (DSP) algorithms are studied to compensate for physical layer impairments in optical fiber coherent communication systems. The physical layer impairments investigated in this thesis include optical fiber chromatic dispersion, polarization demultiplexing...

Tactile band : accessing gaze signals from the sighted in face-to-face communication

NARCIS (Netherlands)

Qiu, S.; Rauterberg, G.W.M.; Hu, J.

2016-01-01

Gaze signals, frequently used by the sighted in social interactions as visual cues, are hardly accessible for low-vision and blind people. A concept is proposed to help the blind people access and react to gaze signals in face-to-face communication. 20 blind and low-vision participants were

A GPS-free passive acoustic localization scheme for underwater wireless sensor networks

KAUST Repository

Mirza, Mohammed

2011-10-01

Seaweb is an acoustic communication technology that enables communication between sensor nodes. Seaweb interconnects the underwater nodes through digital signal processing (DSP)-based modem by using acoustic links between the neighbouring sensors. In this paper, we design and investigate a global positioning system (GPS)-free passive localization protocol using seaweb technology. This protocol uses the range data and planar trigonometry to estimate the positions of the discovered nodes. We take into consideration the small displacement of sensor nodes due to watch circles and placement of sensor nodes on non-uniform underwater surface, for precise localization. Once the nodes are localized, we divide the whole network .eld into circular levels that minimizes the traf.c complexity and thereby increases the lifetime of the sensor network .eld. We then form the mesh network inside each of the circular levels that increases the reliability. The algorithm is designed in such a way that it overcomes the ambiguous nodes errata and re.ected paths and makes the algorithm more robust. The synthetic network geometries are so designed which can evaluate the algorithm in the presence of perfect or imperfect ranges or in case of incomplete data. A comparative study is made with the existing algorithms which proves our newly proposed algorithm to be more effective. © 2011 IEEE.

A Simple Semaphore Signaling Technique for Ultra-High Frequency Spacecraft Communications

Science.gov (United States)

Butman, S.; Satorius, E.; Illott, P.

2005-11-01

For planetary lander missions such as the upcoming Phoenix mission to Mars, the most challenging phase of the spacecraft-to-ground communications is during the critical phase termed entry, descent, and landing (EDL). At 8.4 GHz (X-band), the signals received by the largest Deep Space Network (DSN) antennas can be too weak for even 1 bit per second (bps) and therefore not able to communicate critical information to Earth. Fortunately, the lander's ultra-high frequency (UHF) link to an orbiting relay can meet the EDL requirements, but the data rate needs to be low enough to fit the capability of the UHF link during some or all of EDL. On Phoenix, the minimum data rate of the as-built UHF radio is 8 kbps and requires a signal level at the Odyssey orbiter of at least minus 120 dBm. For lower signaling levels, the effective data rate needs to be reduced, but without incurring the cost of rebuilding and requalifying the equipment. To address this scenario, a simple form of frequency-shift keying (FSK) has been devised by appropriately programming the data stream that is input to the UHF transceiver. This article describes this technique and provides performance estimates. Laboratory testing reveals that input signal levels at minus 140 dBm and lower can routinely be demodulated with the proposed signaling scheme, thereby providing a 20-dB and greater margin over the 8-kbps threshold.

Acoustic rainbow trapping by coiling up space

KAUST Repository

Ni, Xu

2014-11-13

We numerically realize the acoustic rainbow trapping effect by tapping an air waveguide with space-coiling metamaterials. Due to the high refractive-index of the space-coiling metamaterials, our device is more compact compared to the reported trapped-rainbow devices. A numerical model utilizing effective parameters is also calculated, whose results are consistent well with the direct numerical simulation of space-coiling structure. Moreover, such device with the capability of dropping different frequency components of a broadband incident temporal acoustic signal into different channels can function as an acoustic wavelength division de-multiplexer. These results may have potential applications in acoustic device design such as an acoustic filter and an artificial cochlea.

Acoustic rainbow trapping by coiling up space

KAUST Repository

Ni, Xu; Wu, Ying; Chen, Ze-Guo; Zheng, Li-Yang; Xu, Ye-Long; Nayar, Priyanka; Liu, Xiao-Ping; Lu, Ming-Hui; Chen, Yan-Feng

2014-01-01

We numerically realize the acoustic rainbow trapping effect by tapping an air waveguide with space-coiling metamaterials. Due to the high refractive-index of the space-coiling metamaterials, our device is more compact compared to the reported trapped-rainbow devices. A numerical model utilizing effective parameters is also calculated, whose results are consistent well with the direct numerical simulation of space-coiling structure. Moreover, such device with the capability of dropping different frequency components of a broadband incident temporal acoustic signal into different channels can function as an acoustic wavelength division de-multiplexer. These results may have potential applications in acoustic device design such as an acoustic filter and an artificial cochlea.

Analysis on the Acoustic Emission Signals in the Crack Evolution of Steam Generator Tube

International Nuclear Information System (INIS)

Han, Jung Ho; Hur, Do Haeng; Kim, Kyung Mo; Choi, Myung Sik; Lee, Deok Hyun

2007-01-01

The evolution of a defect in steam generator (SG) tube during plant operation can be classified into the stages of initiation and propagation. However, the detection and discrimination of these two stages are difficult, and the real time monitoring of the defect evolution in plant operation is impossible. Moreover, it was generally known that the commercial nondestructive examination techniques such as eddy current test(ECT) can detect the defect already grown up to the size of more than 40% in tube wall thickness. Therefore, the scope of the present study is to develop the fundamental technology for monitoring the degradation process from the initiation stage to the subsequent propagation stage by acoustic emission (AE) signal measurement

Leak detection and localization system through acoustics; Sistema de deteccao e localizacao de vazamentos por acustica

Energy Technology Data Exchange (ETDEWEB)

Alonso, Julio [Aselco Automacao, Sao Paulo, SP (Brazil)

2003-07-01

Acoustic Leak Detection Systems (ALDS) are used on both liquid and gas pipelines as well as multi-phase flow pipelines to detect leaks quickly and provide a means of limiting product loss. The real-time acoustic signal is continuously compared against signature leak profiles for the particular operating and geometric conditions. These profiles were developed from a database established from over 20 years of experimental and field leak tests. This technique not only drastically reduces the false alarm rate, but also significantly improves the sensitivity and leak location accuracy. This system will also detect leaks with shut-in flow (zero flow rate in the pipeline). With the use of GPS (Global Positioning System) it not only improves leak location accuracy, but also allows for continuous leak detection during the loss of communications. (author)

A micro-Doppler sonar for acoustic surveillance in sensor networks

Science.gov (United States)

Zhang, Zhaonian

Wireless sensor networks have been employed in a wide variety of applications, despite the limited energy and communication resources at each sensor node. Low power custom VLSI chips implementing passive acoustic sensing algorithms have been successfully integrated into an acoustic surveillance unit and demonstrated for detection and location of sound sources. In this dissertation, I explore active and passive acoustic sensing techniques, signal processing and classification algorithms for detection and classification in a multinodal sensor network environment. I will present the design and characterization of a continuous-wave micro-Doppler sonar to image objects with articulated moving components. As an example application for this system, we use it to image gaits of humans and four-legged animals. I will present the micro-Doppler gait signatures of a walking person, a dog and a horse. I will discuss the resolution and range of this micro-Doppler sonar and use experimental results to support the theoretical analyses. In order to reduce the data rate and make the system amenable to wireless sensor networks, I will present a second micro-Doppler sonar that uses bandpass sampling for data acquisition. Speech recognition algorithms are explored for biometric identifications from one's gait, and I will present and compare the classification performance of the two systems. The acoustic micro-Doppler sonar design and biometric identification results are the first in the field as the previous work used either video camera or microwave technology. I will also review bearing estimation algorithms and present results of applying these algorithms for bearing estimation and tracking of moving vehicles. Another major source of the power consumption at each sensor node is the wireless interface. To address the need of low power communications in a wireless sensor network, I will also discuss the design and implementation of ultra wideband transmitters in a three dimensional

Signal interactions and interference in insect choruses: singing and listening in the social environment.

Science.gov (United States)

Greenfield, Michael D

2015-01-01

Acoustic insects usually sing amidst conspecifics, thereby creating a social environment-the chorus-in which individuals communicate, find mates, and avoid predation. A temporal structure may arise in a chorus because of competitive and cooperative factors that favor certain signal interactions between neighbors. This temporal structure can generate significant acoustic interference among singers that pose problems for communication, mate finding, and predator detection. Acoustic insects can reduce interference by means of selective attention to only their nearest neighbors and by alternating calls with neighbors. Alternatively, they may synchronize, allowing them to preserve call rhythm and also to listen for predators during the silent intervals between calls. Moreover, males singing in choruses may benefit from reduced per capita predation risk as well as enhanced vigilance. They may also enjoy greater per capita attractiveness to females, particularly in the case of synchronous choruses. In many cases, however, the overall temporal structure of the chorus is only an emergent property of simple, pairwise interactions between neighbors. Nonetheless, the chorus that emerges can impose significant selection pressure on the singing of those individual males. Thus, feedback loops may occur and potentially influence traits at both individual and group levels in a chorus.

Acoustic explorations of the upper ocean boundary layer

Science.gov (United States)

Vagle, Svein

2005-04-01

The upper ocean boundary layer is an important but difficult to probe part of the ocean. A better understanding of small scale processes at the air-sea interface, including the vertical transfer of gases, heat, mass and momentum, are crucial to improving our understanding of the coupling between atmosphere and ocean. Also, this part of the ocean contains a significant part of the total biomass at all trophic levels and is therefore of great interest to researchers in a range of different fields. Innovative measurement plays a critical role in developing our understanding of the processes involved in the boundary layer, and the availability of low-cost, compact, digital signal processors and sonar technology in self-contained and cabled configurations has led to a number of exciting developments. This talk summarizes some recent explorations of this dynamic boundary layer using both active and passive acoustics. The resonant behavior of upper ocean bubbles combined with single and multi-frequency broad band active and passive devices are now giving us invaluable information on air-sea gas transfer, estimation of biological production, marine mammal behavior, wind speed and precipitation, surface and internal waves, turbulence, and acoustic communication in the surf zone.

Sub-sampling-based 2D localization of an impulsive acoustic source in reverberant environments

KAUST Repository

Omer, Muhammad

2014-07-01

This paper presents a robust method for two-dimensional (2D) impulsive acoustic source localization in a room environment using low sampling rates. The proposed method finds the time delay from the room impulse response (RIR) which makes it robust against room reverberations. We consider the RIR as a sparse phenomenon and apply a recently proposed sparse signal reconstruction technique called orthogonal clustering (OC) for its estimation from the sub-sampled received signal. The arrival time of the direct path signal at a pair of microphones is identified from the estimated RIR, and their difference yields the desired time delay estimate (TDE). Low sampling rates reduces the hardware and computational complexity and decreases the communication between the microphones and the centralized location. Simulation and experimental results of an actual hardware setup are presented to demonstrate the performance of the proposed technique.

Sub-sampling-based 2D localization of an impulsive acoustic source in reverberant environments

KAUST Repository

Omer, Muhammad; Quadeer, Ahmed A; Sharawi, Mohammad S; Al-Naffouri, Tareq Y.

2014-01-01

This paper presents a robust method for two-dimensional (2D) impulsive acoustic source localization in a room environment using low sampling rates. The proposed method finds the time delay from the room impulse response (RIR) which makes it robust against room reverberations. We consider the RIR as a sparse phenomenon and apply a recently proposed sparse signal reconstruction technique called orthogonal clustering (OC) for its estimation from the sub-sampled received signal. The arrival time of the direct path signal at a pair of microphones is identified from the estimated RIR, and their difference yields the desired time delay estimate (TDE). Low sampling rates reduces the hardware and computational complexity and decreases the communication between the microphones and the centralized location. Simulation and experimental results of an actual hardware setup are presented to demonstrate the performance of the proposed technique.

Behavioral and Single-Neuron Sensitivity to Millisecond Variations in Temporally Patterned Communication Signals.

Science.gov (United States)

Baker, Christa A; Ma, Lisa; Casareale, Chelsea R; Carlson, Bruce A

2016-08-24

In many sensory pathways, central neurons serve as temporal filters for timing patterns in communication signals. However, how a population of neurons with diverse temporal filtering properties codes for natural variation in communication signals is unknown. Here we addressed this question in the weakly electric fish Brienomyrus brachyistius, which varies the time intervals between successive electric organ discharges to communicate. These fish produce an individually stereotyped signal called a scallop, which consists of a distinctive temporal pattern of ∼8-12 electric pulses. We manipulated the temporal structure of natural scallops during behavioral playback and in vivo electrophysiology experiments to probe the temporal sensitivity of scallop encoding and recognition. We found that presenting time-reversed, randomized, or jittered scallops increased behavioral response thresholds, demonstrating that fish's electric signaling behavior was sensitive to the precise temporal structure of scallops. Next, using in vivo intracellular recordings and discriminant function analysis, we found that the responses of interval-selective midbrain neurons were also sensitive to the precise temporal structure of scallops. Subthreshold changes in membrane potential recorded from single neurons discriminated natural scallops from time-reversed, randomized, and jittered sequences. Pooling the responses of multiple neurons improved the discriminability of natural sequences from temporally manipulated sequences. Finally, we found that single-neuron responses were sensitive to interindividual variation in scallop sequences, raising the question of whether fish may analyze scallop structure to gain information about the sender. Collectively, these results demonstrate that a population of interval-selective neurons can encode behaviorally relevant temporal patterns with millisecond precision. The timing patterns of action potentials, or spikes, play important roles in representing

Modeling ground vehicle acoustic signatures for analysis and synthesis

International Nuclear Information System (INIS)

Haschke, G.; Stanfield, R.

1995-01-01

Security and weapon systems use acoustic sensor signals to classify and identify moving ground vehicles. Developing robust signal processing algorithms for this is expensive, particularly in presence of acoustic clutter or countermeasures. This paper proposes a parametric ground vehicle acoustic signature model to aid the system designer in understanding which signature features are important, developing corresponding feature extraction algorithms and generating low-cost, high-fidelity synthetic signatures for testing. The authors have proposed computer-generated acoustic signatures of armored, tracked ground vehicles to deceive acoustic-sensored smart munitions. They have developed quantitative measures of how accurately a synthetic acoustic signature matches those produced by actual vehicles. This paper describes parameters of the model used to generate these synthetic signatures and suggests methods for extracting these parameters from signatures of valid vehicle encounters. The model incorporates wide-bandwidth and narrow- bandwidth components that are modulated in a pseudo-random fashion to mimic the time dynamics of valid vehicle signatures. Narrow- bandwidth feature extraction techniques estimate frequency, amplitude and phase information contained in a single set of narrow frequency- band harmonics. Wide-bandwidth feature extraction techniques estimate parameters of a correlated-noise-floor model. Finally, the authors propose a method of modeling the time dynamics of the harmonic amplitudes as a means adding necessary time-varying features to the narrow-bandwidth signal components. The authors present results of applying this modeling technique to acoustic signatures recorded during encounters with one armored, tracked vehicle. Similar modeling techniques can be applied to security systems

Industrial installation surveillance acoustic device

International Nuclear Information System (INIS)

Marini, Jean; Audenard, Bernard.

1981-01-01

The purpose of this invention is the detection of possible impacts of bodies migrating inside the installation, using acoustic sensors of the waves emitted at the time of impact of the migrating bodies. This device makes it possible to take into account only those acoustic signals relating to the impacts of bodies migrating in the area under surveillance, to the exclusion of any other acoustic or electric perturbing phenomenon. The invention has a preferential use in the case of a linear shape installation in which a fluid flows at high rate, such as a section of the primary system of a pressurized water nuclear reactor [fr

An accurate quantification of the flow structure along the acoustic signal cycle in a forced two-phase jet

Directory of Open Access Journals (Sweden)

Calvo Bernad Esteban

2014-03-01

Full Text Available This paper provides an experimental study of an acoustically forced two-phase air jet generated by a convergent nozzle. The used particles are transparent glass spheres with diameters between 2 and 50 μm (which gives Stokes number of order 1 and the selected forcing frequency (f=400 Hz induces a powerful nearly periodic flow pattern. Measurements were done by a two-colour Phase-Doppler Anemometer. The experimental setup is computer-controlled to provide an accurate control with a high long-term stability. Measurements cover the whole forcing signal cycle. Raw measurements were carefully post-processed to avoid bias induced by the forcing and the instrument setup, as well as obtain right mean values of the dispersed flow. The effect of the forcing and the particle load allows authors to establish the effect of the acoustic forcing and the particle load on the jet.

Analysis and Classification of Acoustic Emission Signals During Wood Drying Using the Principal Component Analysis

Energy Technology Data Exchange (ETDEWEB)

Kang, Ho Yang [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Kim, Ki Bok [Chungnam National University, Daejeon (Korea, Republic of)

2003-06-15

In this study, acoustic emission (AE) signals due to surface cracking and moisture movement in the flat-sawn boards of oak (Quercus Variablilis) during drying under the ambient conditions were analyzed and classified using the principal component analysis. The AE signals corresponding to surface cracking showed higher in peak amplitude and peak frequency, and shorter in rise time than those corresponding to moisture movement. To reduce the multicollinearity among AE features and to extract the significant AE parameters, correlation analysis was performed. Over 99% of the variance of AE parameters could be accounted for by the first to the fourth principal components. The classification feasibility and success rate were investigated in terms of two statistical classifiers having six independent variables (AE parameters) and six principal components. As a result, the statistical classifier having AE parameters showed the success rate of 70.0%. The statistical classifier having principal components showed the success rate of 87.5% which was considerably than that of the statistical classifier having AE parameters

Analysis and Classification of Acoustic Emission Signals During Wood Drying Using the Principal Component Analysis

International Nuclear Information System (INIS)

Kang, Ho Yang; Kim, Ki Bok

2003-01-01

In this study, acoustic emission (AE) signals due to surface cracking and moisture movement in the flat-sawn boards of oak (Quercus Variablilis) during drying under the ambient conditions were analyzed and classified using the principal component analysis. The AE signals corresponding to surface cracking showed higher in peak amplitude and peak frequency, and shorter in rise time than those corresponding to moisture movement. To reduce the multicollinearity among AE features and to extract the significant AE parameters, correlation analysis was performed. Over 99% of the variance of AE parameters could be accounted for by the first to the fourth principal components. The classification feasibility and success rate were investigated in terms of two statistical classifiers having six independent variables (AE parameters) and six principal components. As a result, the statistical classifier having AE parameters showed the success rate of 70.0%. The statistical classifier having principal components showed the success rate of 87.5% which was considerably than that of the statistical classifier having AE parameters

Large-signal modulation characteristics of a GaN-based micro-LED for Gbps visible-light communication

Science.gov (United States)

Tian, Pengfei; Wu, Zhengyuan; Liu, Xiaoyan; Fang, Zhilai; Zhang, Shuailong; Zhou, Xiaolin; Liu, Kefu; Liu, Ming-Gang; Chen, Shu-Jhih; Lee, Chia-Yu; Cong, Chunxiao; Hu, Laigui; Qiu, Zhi-Jun; Zheng, Lirong; Liu, Ran

2018-04-01

The large-signal modulation characteristics of a GaN-based micro-LED have been studied for Gbps visible-light communication. With an increasing signal modulation depth the modulation bandwidth decreases, which matches up with the increase in the sum of the signal rise time and fall time. By simulating the band diagram and the carrier recombination rate of the micro-LED under large-signal modulation, carrier recombination and the carrier sweep-out effect are analyzed and found to be the dominant mechanisms behind the variation of modulation bandwidth. These results give further insight into improving the modulation bandwidth for high-speed visible-light communication.

Portable acoustic myography

DEFF Research Database (Denmark)

Harrison, Adrian Paul; Danneskiold-Samsøe, Bente; Bartels, Else Marie

2013-01-01

Muscle sound gives a local picture of muscles involved in a particular movement and is independent of electrical signals between nerve and muscle. Sound recording (acoustic myography) is a well-known noninvasive technique that has suffered from not being easily applicable, as well as not being able...

Vectorial signalling mechanism required for cell-cell communication during sporulation in Bacillus subtilis.

Science.gov (United States)

Diez, Veronica; Schujman, Gustavo E; Gueiros-Filho, Frederico J; de Mendoza, Diego

2012-01-01

Spore formation in Bacillus subtilis takes place in a sporangium consisting of two chambers, the forespore and the mother cell, which are linked by pathways of cell-cell communication. One pathway, which couples the proteolytic activation of the mother cell transcription factor σ(E) to the action of a forespore synthesized signal molecule, SpoIIR, has remained enigmatic. Signalling by SpoIIR requires the protein to be exported to the intermembrane space between forespore and mother cell, where it will interact with and activate the integral membrane protease SpoIIGA. Here we show that SpoIIR signal activity as well as the cleavage of its N-terminal extension is strictly dependent on the prespore fatty acid biosynthetic machinery. We also report that a conserved threonine residue (T27) in SpoIIR is required for processing, suggesting that signalling of SpoIIR is dependent on fatty acid synthesis probably because of acylation of T27. In addition, SpoIIR localization in the forespore septal membrane depends on the presence of SpoIIGA. The orchestration of σ(E) activation in the intercellular space by an acylated signal protein provides a new paradigm to ensure local transmission of a weak signal across the bilayer to control cell-cell communication during development. © 2011 Blackwell Publishing Ltd.

Acoustic manipulation of bacteria cells suspensions

Science.gov (United States)

GutiéRrez-Ramos, Salomé; Hoyos, Mauricio; Aider, Jean Luc; Ruiz, Carlos; Acoustofluidics Team Team; Soft; Bio Group Collaboration

An acoustic contacless manipulation gives advantages in the exploration of the complex dynamics enviroment that active matter exhibits. Our works reports the control confinement and dispersion of Escherichia coliRP437-pZA3R-YFP suspensions (M9Glu-Ca) via acoustic levitation.The manipulation of the bacteria bath in a parallel plate resonator is achieved using the acoustic radiation force and the secondary radiation force. The primary radiation force generates levitation of the bacteria cells at the nodal plane of the ultrasonic standing wave generated inside the resonator. On the other side, secondary forces leads to the consolidation of stable aggregates. All the experiments were performed in the acoustic trap described, where we excite the emission plate with a continuous sinusoidal signal at a frequency in the order of MHz and a quartz slide as the reflector plate. In a typical experiment we observed that, before the input of the signal, the bacteria cells exhibit their typical run and tumble behavior and after the sound is turned on all of them displace towards the nodal plane, and instantaneously the aggregation begins in this region. CNRS French National Space Studies, CONACYT Mexico.

Acoustic Measurement of the Length of Air-plasma Filament Induced by an Intense Femtosecond Laser Pulse

Directory of Open Access Journals (Sweden)

Wu Si-Qing

2017-01-01

Full Text Available The paper studies acoustic emission from air-plasma filament induced by a strong femtosecond laser pulse. Acoustic signal is detected with a sensitive directional microphone. Acoustic measurement provides a new method to determine the length of a filament. Compared with other methods, acoustic measurement is simpler, more sensitive, and with higher spatial resolution. Information of filament length is experimentally acquired through measuring acoustic pressure at different position of filament. On the basis of the relationship between acoustic signal and free-electron density in filament, profile of free-electron density is demonstrated

Acoustic analysis of trill sounds.

Science.gov (United States)