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Formant frequencies of Malay vowels produced by Malay children aged between 7 and 12 years

Ting HN, Zourmand A, Chia SY, Yong BF, Abdul Hamid B

J Voice, 2012 Sep;26(5):664.e1-6.
PMID: 22285457 DOI: 10.1016/j.jvoice.2011.08.008

The formant frequencies of Malaysian Malay children have not been well studied. This article investigates the first four formant frequencies of sustained vowels in 360 Malay children aged between 7 and 12 years using acoustical analysis. Generally, Malay female children had higher formant frequencies than those of their male counterparts. However, no significant differences in all four formant frequencies were observed between the Malay male and female children in most of the vowels and age groups. Significant differences in all formant frequencies were found across the Malay vowels in both Malay male and female children for all age groups except for F4 in female children aged 12 years. Generally, the Malaysian Malay children showed a nonsystematic decrement in formant frequencies with age. Low levels of significant differences in formant frequencies were observed across the age groups in most of the vowels for F1, F3, and F4 in Malay male children and F1 and F4 in Malay female children.

Matched MeSH terms: Speech Acoustics*
Fundamental frequency and perturbation measures of sustained vowels in Malaysian Malay children between 7 and 12 years old

Ting HN, Chia SY, Manap HH, Ho AH, Tiu KY, Abdul Hamid B

J Voice, 2012 Jul;26(4):425-30.
PMID: 22243972 DOI: 10.1016/j.jvoice.2011.07.001

The study is going to investigate the fundamental frequency (F(0)) and perturbation measures of sustained vowels in 360 native Malaysian Malay children aged between 7 and 12 years using acoustical analysis.

Matched MeSH terms: Speech Acoustics*
Vocal fundamental frequency and perturbation measurements of vowels by normal Malaysian Chinese adults

Ting HN, Chia SY, Kim KS, Sim SL, Abdul Hamid B

J Voice, 2011 Nov;25(6):e311-7.
PMID: 21376529 DOI: 10.1016/j.jvoice.2010.05.004

The acoustic properties of vowel phonation vary across cultures. These specific characteristics, including vowel fundamental frequency (F(0)) and perturbation measures (Absolute Jitter [Jita], Jitter [Jitt], Relative Average Perturbation [RAP], five-point Period Perturbation Quotient [PPQ5], Absolute Shimmer [ShdB], Shimmer [Shim], and 11-point Amplitude Perturbation Quotient [APQ11]) are not well established for Malaysian Chinese adults. This article investigates the F(0) and perturbation measurements of sustained vowels in 60 normal Malaysian Chinese adults using acoustical analysis. Malaysian Chinese females had significantly higher F(0) than Malaysian males in all six vowels. However, there were no significant differences in F(0) across the vowels for each gender. Significant differences between vowels were observed for Jita, Jitt, PPQ5, ShdB, Shim, and APQ11 among Chinese males, whereas significant differences between vowels were observed for all the perturbation parameters among Chinese females. Chinese males had significantly higher Jita and APQ11 in the vowels than Chinese females, whereas no significant differences were observed between males and females for Jitt, RAP, PPQ5, and Shim. Cross-ethnic comparisons indicate that F(0) of vowel phonation varies within the Chinese ethnic group and across other ethnic groups. The perturbation measures cannot be simply compared, where the measures may vary significantly across different speech analysis softwares.

Matched MeSH terms: Speech Acoustics*
Tissue-mimicking gel phantoms for thermal therapy studies

Dabbagh A, Abdullah BJ, Ramasindarum C, Abu Kasim NH

Ultrason Imaging, 2014 Oct;36(4):291-316.
PMID: 24626566 DOI: 10.1177/0161734614526372

Tissue-mimicking phantoms that are currently available for routine biomedical applications may not be suitable for high-temperature experiments or calibration of thermal modalities. Therefore, design and fabrication of customized thermal phantoms with tailored properties are necessary for thermal therapy studies. A multitude of thermal phantoms have been developed in liquid, solid, and gel forms to simulate biological tissues in thermal therapy experiments. This article is an attempt to outline the various materials and techniques used to prepare thermal phantoms in the gel state. The relevant thermal, electrical, acoustic, and optical properties of these phantoms are presented in detail and the benefits and shortcomings of each type are discussed. This review could assist the researchers in the selection of appropriate phantom recipes for their in vitro study of thermal modalities and highlight the limitations of current phantom recipes that remain to be addressed in further studies.

Matched MeSH terms: Acoustics
Emotional speech acoustic model for Malay: iterative versus isolated unit training

Mustafa MB, Ainon RN

J Acoust Soc Am, 2013 Oct;134(4):3057-66.
PMID: 24116440 DOI: 10.1121/1.4818741

The ability of speech synthesis system to synthesize emotional speech enhances the user's experience when using this kind of system and its related applications. However, the development of an emotional speech synthesis system is a daunting task in view of the complexity of human emotional speech. The more recent state-of-the-art speech synthesis systems, such as the one based on hidden Markov models, can synthesize emotional speech with acceptable naturalness with the use of a good emotional speech acoustic model. However, building an emotional speech acoustic model requires adequate resources including segment-phonetic labels of emotional speech, which is a problem for many under-resourced languages, including Malay. This research shows how it is possible to build an emotional speech acoustic model for Malay with minimal resources. To achieve this objective, two forms of initialization methods were considered: iterative training using the deterministic annealing expectation maximization algorithm and the isolated unit training. The seed model for the automatic segmentation is a neutral speech acoustic model, which was transformed to target emotion using two transformation techniques: model adaptation and context-dependent boundary refinement. Two forms of evaluation have been performed: an objective evaluation measuring the prosody error and a listening evaluation to measure the naturalness of the synthesized emotional speech.

Matched MeSH terms: Acoustics*; Speech Acoustics*
Fulltext Engineering Properties of Waste Sawdust-Based Lightweight Alkali-Activated Concrete: Experimental Assessment and Numerical Prediction

Alabduljabbar H, Huseien GF, Sam ARM, Alyouef R, Algaifi HA, Alaskar A

Materials (Basel), 2020 Dec 02;13(23).
PMID: 33276508 DOI: 10.3390/ma13235490

Alkali activated concretes have emerged as a prospective alternative to conventional concrete wherein diverse waste materials have been converted as valuable spin-offs. This paper presents a wide experimental study on the sustainability of employing waste sawdust as a fine/coarse aggregate replacement incorporating fly ash (FA) and granulated blast furnace slag (GBFS) to make high-performance cement-free lightweight concretes. Waste sawdust was replaced with aggregate at 0, 25, 50, 75, and 100 vol% incorporating alkali binder, including 70% FA and 30% GBFS. The blend was activated using a low sodium hydroxide concentration (2 M). The acoustic, thermal, and predicted engineering properties of concretes were evaluated, and the life cycle of various mixtures were calculated to investigate the sustainability of concrete. Besides this, by using the available experimental test database, an optimized Artificial Neural Network (ANN) was developed to estimate the mechanical properties of the designed alkali-activated mortar mixes depending on each sawdust volume percentage. Based on the findings, it was found that the sound absorption and reduction in thermal conductivity were enhanced with increasing sawdust contents. The compressive strengths of the specimens were found to be influenced by the sawdust content and the strength dropped from 65 to 48 MPa with the corresponding increase in the sawdust levels from 0% up to 100%. The results also showed that the emissions of carbon dioxide, energy utilization, and outlay tended to drop with an increase in the amount of sawdust and show more the lightweight concrete to be more sustainable for construction applications.

Matched MeSH terms: Acoustics
Fulltext Non-Destructive Evaluation for Corrosion Monitoring in Concrete: A Review and Capability of Acoustic Emission Technique

Zaki A, Chai HK, Aggelis DG, Alver N

Sensors (Basel), 2015;15(8):19069-101.
PMID: 26251904 DOI: 10.3390/s150819069

Corrosion of reinforced concrete (RC) structures has been one of the major causes of structural failure. Early detection of the corrosion process could help limit the location and the extent of necessary repairs or replacement, as well as reduce the cost associated with rehabilitation work. Non-destructive testing (NDT) methods have been found to be useful for in-situ evaluation of steel corrosion in RC, where the effect of steel corrosion and the integrity of the concrete structure can be assessed effectively. A complementary study of NDT methods for the investigation of corrosion is presented here. In this paper, acoustic emission (AE) effectively detects the corrosion of concrete structures at an early stage. The capability of the AE technique to detect corrosion occurring in real-time makes it a strong candidate for serving as an efficient NDT method, giving it an advantage over other NDT methods.

Matched MeSH terms: Acoustics
Selective Laryngeal Examination: Sensitivity of Endocrine Surgeons in Screening Voice Abnormality

Al-Yahya SN, Muhammad R, Suhaimi SNA, Azman M, Mohamed AS, Baki MM

J Voice, 2020 Sep;34(5):811.e13-811.e20.
PMID: 30612893 DOI: 10.1016/j.jvoice.2018.12.003

OBJECTIVES: Selective laryngeal examination for patients undergoing thyroidectomy is recommended for patients with voice alterations, history of prior cervical or chest surgery, and patients with proven or suspected thyroid malignancy. The study objective is to measure the sensitivity of surgeons in detecting voice abnormalities in patients undergoing thyroidectomy, parathyroidectomy complicated with laryngeal nerve paralysis, or patients with known vocal cords palsy (VCP) due to other neck surgeries.
DESIGN AND SETTING: Descriptive cross-sectional study in a tertiary center.
PARTICIPANTS AND METHODS: The subjects are 274 audio files of voices of patients undergoing thyroid, parathyroid surgeries, and known VCP due to other neck surgeries. Voice assessments were done by three endocrine surgeons (A, B, and C) with 20, 12, and 4 years of surgical experience.
MAIN OUTCOME MEASURES: Sensitivity and specificity of surgeon documented voice assessment in patients with underlying VCP. Subjects' acoustic analysis and Voice Handicap Index (VHI-10) were analyzed.
RESULTS: Raters A, B, and C have sensitivity of 63.6%, 78.8%, and 66.7%, respectively. Inter-rater reliability shows substantial agreement (ƙ = 0.67). VHI-10 has sensitivity of 75.8% and strong correlation of 0.707 (p value <0.001) to VCP. Subjects with VCP have notably higher jitter, shimmer, and noise-to-harmonic ratio compared to normal subjects with sensitivity of 74.2%, 71.2%, and 72.7%, respectively.
CONCLUSIONS: The results for surgeons documented voice assessment did not reach the desired sensitivity for a screening tool for patients with underlying VCP. Other tools such as VHI-10 and acoustic analysis may not be used as standalone tools in screening patients with underlying VCP. Routine preoperative laryngeal examination may be recommended for all patients undergoing thyroid, parathyroid, or other surgeries that places the laryngeal nerves at risk.

Matched MeSH terms: Acoustics
Maximum vocal intensity as a primary outcome measure in unilateral vocal fold paralysis patients

Johari SF, Azman M, Mohamed AS, Baki MM

J Laryngol Otol, 2020 Dec;134(12):1085-1093.
PMID: 33308327 DOI: 10.1017/S0022215120002558

OBJECTIVE: To evaluate voice intensity as the primary outcome measurement when treating unilateral vocal fold paralysis patients.
METHODS: This prospective observational study comprised 34 newly diagnosed unilateral vocal fold paralysis patients undergoing surgical interventions: injection laryngoplasty or medialisation thyroplasty. Voice assessments, including maximum vocal intensity and other acoustic parameters, were performed at baseline and at one and three months post-intervention. Maximum vocal intensity was also repeated within two weeks before any surgical interventions were performed. The results were compared between different time points and between the two intervention groups.
RESULTS: Maximum vocal intensity showed high internal consistency. Statistically significant improvements were seen in maximum vocal intensity, Voice Handicap Index-10 and other acoustic analyses at one and three months post-intervention. A significant moderate negative correlation was demonstrated between maximum vocal intensity and Voice Handicap Index-10, shimmer and jitter. There were no significant differences in voice outcomes between injection laryngoplasty and medialisation thyroplasty patients at any time point.
CONCLUSION: Maximum vocal intensity can be applied as a treatment outcome measure in unilateral vocal fold paralysis patients; it can demonstrate the effectiveness of treatment and moderately correlates with self-reported outcome measures.

Matched MeSH terms: Speech Acoustics
Demarcating and highlighting in Papuan Malay phrase prosody

Kaland C, Baumann S

J Acoust Soc Am, 2020 04;147(4):2974.
PMID: 32359299 DOI: 10.1121/10.0001008

Phrase-level prosody serves two essential functions in many languages of the world: chunking information into units (demarcating) and marking important information (highlighting). Recent work suggests that prosody has a mainly demarcating function in the Trade Malay language family. That is, the use of pitch accents in these languages is limited or absent, as the main prosodic events occur on the final two syllables in a phrase. The current study investigates the extent to which Papuan Malay phrase prosody is used for demarcating and highlighting, taking into account the potential influence of word stress. This is done by means of acoustic analyses on a corpus of spontaneous speech. Both the form (F0 movement) and the possible functions (demarcating and highlighting) of the final two syllables in Papuan Malay phrases are investigated. Although most results favor the demarcating function of Papuan Malay phrase prosody, a highlighting function cannot be ruled out. The results suggest that Papuan Malay might hold an exceptional position in the typology of prosodic prominence.

Matched MeSH terms: Speech Acoustics
Fulltext The effects of age on the strategic use of pitch accents in memory for discourse: a processing-resource account

Fraundorf SH, Watson DG, Benjamin AS

Psychol Aging, 2012 Mar;27(1):88-98.
PMID: 21639646 DOI: 10.1037/a0024138

In two experiments, we investigated age-related changes in how prosodic pitch accents affect memory. Participants listened to recorded discourses that contained two contrasts between pairs of items (e.g., one story contrasted British scientists with French scientists and Malaysia with Indonesia). The end of each discourse referred to one item from each pair; these references received a pitch accent that either denoted contrast (L + H* in the ToBI system) or did not (H*). A contrastive accent on a particular pair improved later recognition memory equally for young and older adults. However, older adults showed decreased memory if the other pair received a contrastive accent (Experiment 1). Young adults with low working memory performance also showed this penalty (Experiment 2). These results suggest that pitch accents guide processing resources to important information for both older and younger adults but diminish memory for less important information in groups with reduced resources, including older adults.

Matched MeSH terms: Speech Acoustics*
Fulltext CoSiM-RPO: Cooperative Routing with Sink Mobility for Reliable and Persistent Operation in Underwater Acoustic Wireless Sensor Networks

Ali M, Khan A, Aurangzeb K, Ali I, Mahmood H, Haider SI, et al.

Sensors (Basel), 2019 Mar 04;19(5).
PMID: 30836710 DOI: 10.3390/s19051101

An efficient algorithm for the persistence operation of data routing is crucial due to the uniqueness and challenges of the aqueous medium of the underwater acoustic wireless sensor networks (UA-WSNs). The existing multi-hop algorithms have a high energy cost, data loss, and less stability due to many forwarders for a single-packet delivery. In order to tackle these constraints and limitations, two algorithms using sink mobility and cooperative technique for UA-WSNs are devised. The first one is sink mobility for reliable and persistence operation (SiM-RPO) in UA-WSNs, and the second is the enhanced version of the SiM-RPO named CoSiM-RPO, which utilizes the cooperative technique for better exchanging of the information and minimizes data loss probability. To cover all of the network through mobile sinks (MSs), the division of the network into small portions is accomplished. The path pattern is determined for MSs in a manner to receive data even from a single node in the network. The MSs pick the data directly from the nodes and check them for the errors. When erroneous data are received at the MS, then the relay cooperates to receive correct data. The proposed algorithm boosts the network lifespan, throughput, delay, and stability more than the existing counterpart schemes.

Matched MeSH terms: Acoustics
Reliability of OperaVOX against Multidimensional Voice Program (MDVP)

Mat Baki M, Wood G, Alston M, Ratcliffe P, Sandhu G, Rubin JS, et al.

Clin Otolaryngol, 2015 Feb;40(1):22-8.
PMID: 25263076 DOI: 10.1111/coa.12313

OBJECTIVE: To evaluate the agreement between OperaVOX and MDVP.
DESIGN: Cross sectional reliability study.
SETTING: University teaching hospital.
METHODS: Fifty healthy volunteers and 50 voice disorder patients had supervised recordings in a quiet room using OperaVOX by the iPod's internal microphone with sampling rate of 45 kHz. A five-seconds recording of vowel/a/was used to measure fundamental frequency (F0), jitter, shimmer and noise-to-harmonic ratio (NHR). All healthy volunteers and 21 patients had a second recording. The recorded voices were also analysed using the MDVP. The inter- and intrasoftware reliability was analysed using intraclass correlation (ICC) test and Bland-Altman (BA) method. Mann-Whitney test was used to compare the acoustic parameters between healthy volunteers and patients.
RESULTS: Nine of 50 patients had severe aperiodic voice. The ICC was high with a confidence interval of >0.75 for the inter- and intrasoftware reliability except for the NHR. For the intersoftware BA analysis, excluding the severe aperiodic voice data sets, the bias (95% LOA) of F0, jitter, shimmer and NHR was 0.81 (11.32, -9.71); -0.13 (1.26, -1.52); -0.52 (1.68, -2.72); and 0.08 (0.27, -0.10). For the intrasoftware reliability, it was -1.48 (18.43, -21.39); 0.05 (1.31, -1.21); -0.01 (2.87, -2.89); and 0.005 (0.20, -0.18), respectively. Normative data from the healthy volunteers were obtained. There was a significant difference in all acoustic parameters between volunteers and patients measured by the Opera-VOX (P

Matched MeSH terms: Speech Acoustics*
Fulltext An Inventory of Vowel Phonemes of the Melanau Rajang dialect

MARINA KAWI, DAYANG SARIAH ABANG SUHAI

Trends in Undergraduate Research, 2018;1(1):0-0.
MyJurnal

The study aims to identify an inventory of vowel phonemes of Melanau Rajang dialect in Belawai under the administration of Tanjung Manis District, Sarawak. This study is a field survey using interview methods to obtain data. A total 250 Swadesh list (Samarin, 1967) are used as a guide for data collection. In this study, two infotmants of different genders aged between 40 and 60 years old were selected based on criteria of informant selections according to Asmah Haji Omar (2001). In analysis data, qualitative method is used based on structural approaches. The findings show that there are eight (8) vowel phonemes have been identified; four (4) front vowels [i, e, ε, a]; one (1) central vowel [ə]; and three (3) back vowels [u, o, ɔ]. Besides that, the distribution/alternation of all vowel phonemes of Melanau Rajang dialect in Belawai are also discussed in this study. The findings also indicate that active vowel phonemes are vowels [a, i, u], while inactive vocal phonemes are vowels [ɔ, o, ε, ə, e].

Matched MeSH terms: Speech Acoustics
Direct airborne acoustic wave modulation of Fabry-Perot fiber laser (FPFL) over 100 kHz of operating bandwidth

Pua CH, Ahmad H, Harun SW, De La Rue RM

Appl Opt, 2012 May 20;51(15):2772-7.
PMID: 22614578 DOI: 10.1364/AO.51.002772

The idea of applying a simple Fabry-Perot fiber laser (FPFL) set-up in a free-running condition as an acoustic sensing medium is proposed. Conventional optical microphone requires a stringently aligned diaphragm to mediate the acoustic impedance mismatch between air and silica fiber. Motivated by the difficulty of optical sensing of airborne acoustic waves, a new sensing method is proposed to sense acoustic waves without the assistance of a diaphragm as transducer. By studying the output power fluctuation of the FPFL, the operating bandwidth and sensitivity of the proposed sensing method are determined. The tunability of the resonant frequency from 5 kHz to 85 kHz allows sensing of acoustic waves in the range of 100 Hz to 100 kHz. Tuning of the resonant frequency can be performed by changing the optical pumping power from as low as 10 mW to 68.5 mW or higher.

Matched MeSH terms: Acoustics
Fulltext Correlation between prenatal doppler ultrasound exposure durations and newborn rabbit’s body weight

Umi Nadrah Amran, Farah Wahida Ahmad Zaiki

Malaysian Journal of Medicine and Health Sciences, 2020;16(1):115-120.
MyJurnal

Introduction: Doppler mode ultrasound is widely used in prenatal scanning and known to produce a higher acoustic
output which later leads to higher heat energy conversion compared to other ultrasound modes. It has been reported
that the use of Doppler imaging might increase the temperature of tissues, thus, when Doppler is used in combination with 2D ultrasound, the risks of bioeffects tend to increase more. It is also known that prolonged exposure to
ultrasound during pregnancy can cause irreversible biological destructions to the fetus. Despite the benefits of using
Doppler ultrasound, its potential adverse effects have received scant attention in the research literature. Therefore,
this study aimed to examine a correlation between gestational stages (GS) and newborn rabbit’s body weight at different prenatal Doppler ultrasound exposure durations. Methods: Twelve pregnant New Zealand white rabbits (NZWR)
were exposed once using three different Doppler ultrasound exposure durations (30, 60, 90 minutes exposure) at
three different GSs (1st, 2nd, and 3rd GS). After delivery, the mean weights of the 62 newborns were statistically analysed. Results: Strong negative and positive correlation between newborn’s body weight at different GSs and Doppler
ultrasound exposure durations with a significant result found in 60 minutes exposure (p =

Matched MeSH terms: Acoustics
Fulltext Applications and advances in acoustic monitoring for infectious disease epidemiology

Johnson E, Campos-Cerqueira M, Jumail A, Yusni ASA, Salgado-Lynn M, Fornace K

Trends Parasitol, 2023 May;39(5):386-399.
PMID: 36842917 DOI: 10.1016/j.pt.2023.01.008

Emerging infectious diseases continue to pose a significant burden on global public health, and there is a critical need to better understand transmission dynamics arising at the interface of human activity and wildlife habitats. Passive acoustic monitoring (PAM), more typically applied to questions of biodiversity and conservation, provides an opportunity to collect and analyse audio data in relative real time and at low cost. Acoustic methods are increasingly accessible, with the expansion of cloud-based computing, low-cost hardware, and machine learning approaches. Paired with purposeful experimental design, acoustic data can complement existing surveillance methods and provide a novel toolkit to investigate the key biological parameters and ecological interactions that underpin infectious disease epidemiology.

Matched MeSH terms: Acoustics
Fulltext The role of f0 shape and phrasal position in Papuan Malay and American English word identification

Kaland C, Gordon MK

Phonetica, 2022 Jun 27;79(3):219-245.
PMID: 35981718 DOI: 10.1515/phon-2022-2022

The prosodic structure of under-researched languages in the Trade Malay language family is poorly understood. Although boundary marking has been uncontroversially shown as the major prosodic function in these languages, studies on the use of pitch accents to highlight important words in a phrase remain inconclusive. In addition, most knowledge of pitch accents is based on well-researched languages such as the ones from the Western-Germanic language family. This paper reports two word identification experiments comparing Papuan Malay with the pitch accent language American English, in order to investigate the extent to which the demarcating and highlighting function of prosody can be disentangled. To this end, target words were presented to native listeners of both languages and differed with respect to their position in the phrase (medial or final) and the shape of their f0 movement (original or manipulated). Reaction times for the target word identifications revealed overall faster responses for original and final words compared to manipulated and medial ones. The results add to previous findings on the facilitating effect of pitch accents and further improve our prosodic knowledge of underresearched languages.

Matched MeSH terms: Speech Acoustics
Fulltext QoSRP: A Cross-layer QoS Channel-Aware Routing Protocol for the Internet of Underwater Acoustic Sensor Networks

Faheem M, Butt RA, Raza B, Alquhayz H, Ashraf MW, Shah SB, et al.

Sensors (Basel), 2019 Nov 02;19(21).
PMID: 31684014 DOI: 10.3390/s19214762

Quality of service (QoS)-aware data gathering in static-channel based underwater wireless sensor networks (UWSNs) is severely limited due to location and time-dependent acoustic channel communication characteristics. This paper proposes a novel cross-layer QoS-aware multichannel routing protocol called QoSRP for the internet of UWSNs-based time-critical marine monitoring applications. The proposed QoSRP scheme considers the unique characteristics of the acoustic communication in highly dynamic network topology during gathering and relaying events data towards the sink. The proposed QoSRP scheme during the time-critical events data-gathering process employs three basic mechanisms, namely underwater channel detection (UWCD), underwater channel assignment (UWCA) and underwater packets forwarding (UWPF). The UWCD mechanism finds the vacant channels with a high probability of detection and low probability of missed detection and false alarms. The UWCA scheme assigns high data rates channels to acoustic sensor nodes (ASNs) with longer idle probability in a robust manner. Lastly, the UWPF mechanism during conveying information avoids congestion, data path loops and balances the data traffic load in UWSNs. The QoSRP scheme is validated through extensive simulations conducted by NS2 and AquaSim 2.0 in underwater environments (UWEs). The simulation results reveal that the QoSRP protocol performs better compared to existing routing schemes in UWSNs.

Matched MeSH terms: Acoustics
Fulltext The heterospecific calling song can improve conspecific signal detection in a bushcricket species

Abdelatti ZAS, Hartbauer M

Hear Res, 2017 11;355:70-80.
PMID: 28974384 DOI: 10.1016/j.heares.2017.09.011

In forest clearings of the Malaysian rainforest, chirping and trilling Mecopoda species often live in sympatry. We investigated whether a phenomenon known as stochastic resonance (SR) improved the ability of individuals to detect a low-frequent signal component typical of chirps when members of the heterospecific trilling species were simultaneously active. This phenomenon may explain the fact that the chirping species upholds entrainment to the conspecific song in the presence of the trill. Therefore, we evaluated the response probability of an ascending auditory neuron (TN-1) in individuals of the chirping Mecopoda species to triple-pulsed 2, 8 and 20 kHz signals that were broadcast 1 dB below the hearing threshold while increasing the intensity of either white noise or a typical triller song. Our results demonstrate the existence of SR over a rather broad range of signal-to-noise ratios (SNRs) of input signals when periodic 2 kHz and 20 kHz signals were presented at the same time as white noise. Using the chirp-specific 2 kHz signal as a stimulus, the maximum TN-1 response probability frequently exceeded the 50% threshold if the trill was broadcast simultaneously. Playback of an 8 kHz signal, a common frequency band component of the trill, yielded a similar result. Nevertheless, using the trill as a masker, the signal-related TN-1 spiking probability was rather variable. The variability on an individual level resulted from correlations between the phase relationship of the signal and syllables of the trill. For the first time, these results demonstrate the existence of SR in acoustically-communicating insects and suggest that the calling song of heterospecifics may facilitate the detection of a subthreshold signal component in certain situations. The results of the simulation of sound propagation in a computer model suggest a wide range of sender-receiver distances in which the triller can help to improve the detection of subthreshold signals in the chirping species.

Matched MeSH terms: Acoustics

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