Analysis Of Acoustic Waveforms Research Articles

Ultrasonically induced nanofatigue monitoring during nanoindentation

The ultrasonic nanoindentation tip integrated into a nanoindenter operates at hundreds of kHz, inducing millions of load cycles within seconds at the localized mechanical contact point. Then operating on brittle submicron thick films such as SiC, the resulting accumulated nanofatigue exhibits different contact fracture modes. During the process of quasi-static loading with ultrasonic excitation, the ultrasonic nanoindentation tip monitors associated acoustic waveforms, which can provide additional insights into the nanofatigue process dynamics via advanced acoustic waveform analysis and deep learning classifications.

Fansmitter: Acoustic data exfiltration from air-Gapped computers via fans noise

Computers that contain sensitive information are often maintained in air-gapped isolation. In this defensive measure, a computer is disconnected from the Internet - logically and physically - preventing accidental or intentional leakage of sensitive information outward. In recent years it has been shown that malware can leak data over an air-gap by transmitting sonic and ultrasonic signals from a computer speaker. In order to eliminate such acoustic covert channels, current best practice recommends the elimination of speakers in secured computers, thereby creating a so-called ‘audio-gapped’ system.In this paper, we present ‘Fansmitter,’ a malware that can acoustically exfiltrate data from air-gapped computers, even when audio hardware and speakers are not present. Our method utilizes the noise emitted from the CPU, GPU, and chassis fans. We show that a software can regulate the internal fans’ rotation speed in order to control their acoustic signal, known as blade pass frequency (BPF). Binary data can be modulated and transmitted over these audio signals to a remote microphone (e.g., a nearby smartphone). We present design considerations, including acoustic waveform analysis, data modulation and demodulation, and data transmission and reception. We evaluate the acoustic covert channel with various fans at different distances and present the results. We also discuss issues such as stealth, interference, and countermeasures. Using our method we successfully transmitted data from audio-less, air-gapped computers, to a mobile phone in the same room. We demonstrated an effective transmission at distances of 1–8 m, with a maximum bit rate of 60 bit/min per fan.

X-ray microtomography and linear discriminant analysis enable detection of embolism-related acoustic emissions

BackgroundAcoustic emission (AE) sensing is in use since the late 1960s in drought-induced embolism research as a non-invasive and continuous method. It is very well suited to assess a plant’s vulnerability to dehydration. Over the last couple of years, AE sensing has further improved due to progress in AE sensors, data acquisition methods and analysis systems. Despite these recent advances, it is still challenging to detect drought-induced embolism events in the AE sources registered by the sensors during dehydration, which sometimes questions the quantitative potential of AE sensing.ResultsIn quest of a method to separate embolism-related AE signals from other dehydration-related signals, a 2-year-old potted Fraxinus excelsior L. tree was subjected to a drought experiment. Embolism formation was acoustically measured with two broadband point-contact AE sensors while simultaneously being visualized by X-ray computed microtomography (µCT). A machine learning method was used to link visually detected embolism formation by µCT with corresponding AE signals. Specifically, applying linear discriminant analysis (LDA) on the six AE waveform parameters amplitude, counts, duration, signal strength, absolute energy and partial power in the range 100–200 kHz resulted in an embolism-related acoustic vulnerability curve (VCAE-E) better resembling the standard µCT VC (VCCT), both in time and in absolute number of embolized vessels. Interestingly, the unfiltered acoustic vulnerability curve (VCAE) also closely resembled VCCT, indicating that VCs constructed from all registered AE signals did not compromise the quantitative interpretation of the species’ vulnerability to drought-induced embolism formation.ConclusionAlthough machine learning could detect similar numbers of embolism-related AE as µCT, there still is insufficient model-based evidence to conclusively attribute these signals to embolism events. Future research should therefore focus on similar experiments with more in-depth analysis of acoustic waveforms, as well as explore the possibility of Fast Fourier transformation (FFT) to remove non-embolism-related AE signals.

OP104: Oncologic and functional outcomes of transoral robotic surgery for oropharyngeal cancer

This prospective study analyzed oncologic and functional results of transoral robotic surgery (TORS) and ascertained the validity of TORS as a minimally invasive therapy for oropharyngeal cancer. Between April 2008 and September 2011, 39 patients with oropharyngeal cancer underwent TORS. The Kaplan–Meier method was used to analyze overall and disease-free survival rate. Videopharyngogram study (VEF) and the functional outcome swallowing scale (FOSS) were used to evaluate swallowing function. Nasometer study was conducted to estimate hypernasality, and acoustic waveform analysis was used to evaluate voice status. A negative margin was reported in 94.9% of patients. Overall survival at two years was 96% and disease-free survival was 92%. An oral diet was tolerable after an average of 6.4 days. Significant swallowing difficulties were not observed for the VEF results. Favorable swallowing results were found in 97.4% of patients with FOSS scores ranging from 0 to 2. Voice parameters were maintained close to the normal range on the acoustic waveform analysis. The oncologic and functional results of TORS were quite acceptable for the treatment of oropharyngeal cancer. TORS is a valid treatment option for select patients with oropharyngeal cancer.

Surgical techniques and treatment outcomes of transoral robotic supraglottic partial laryngectomy

The objective of this prospective study was to confirm the validity of transoral robotic supraglottic partial laryngectomy as a conservation surgery for treating supraglottic cancer. Prospective case study. Between December 2009 and November 2011, 16 patients were enrolled in this study. Acoustic waveform analysis was conducted and Voice Handicap Index 10 was measured to assess voice status. Videopharyngogram study and the functional outcome swallowing scale were administered to evaluate swallowing function. Overall survival and disease-free survival were analyzed using the Kaplan-Meier method. A negative margin was reported in 88% patients. During the follow-up period, distant metastasis occurred in one patient at 6 months. The Kaplan-Meier disease-free survival at 1 year was 91%. Patients exhibited complete recovery of swallowing ability after an average of 8.3 days. Videopharyngogram study showed aspiration in one patient. The cannula could be removed at an average 11.2 days. The average hospital stay was 13.5 days. Concerning the results of the functional outcome swallowing scale and Voice Handicap Index 10, most patients (90.9%) subjectively reported favorable swallowing and voice function. Transoral robotic surgery was a safe and feasible modality of treating supraglottic cancer. According to our data, transoral robotic surgery demonstrated oncologically and functionally acceptable results in supraglottic cancer patients.

Oncological and functional outcomes of transoral robotic surgery for oropharyngeal cancer

In this prospective study we analysed the oncological and functional results of transoral robotic surgery (TORS) to find out if it was suitable as a minimally invasive treatment for oropharyngeal cancer. Between April 2008 and September 2011, 39 patients with oropharyngeal cancer were treated by TORS. We assessed overall and disease-free survival by the Kaplan–Meier test, and we used videopharyngography and the functional outcome swallowing scale (FOSS) to evaluate swallowing. We used nasometry to estimate hypernasality, and acoustic waveform analysis to evaluate the voice. Thirty-seven patients (95%) had histologically clear margins of resection. Overall survival at 2 years was 96% and disease-free survival 92%. An oral diet was tolerable after a mean of 6 (range 1–18) days. No serious swallowing difficulties were seen on the videopharyngogram. Thirty-six of 38 patients could swallow well (97%) with FOSS scores ranging from 0 to 2 (1 patient had a poor score but was able to take an oral diet after postural training). Voices were maintained close to the normal range on the acoustic waveform analysis. The oncological and functional results of TORS were quite acceptable for the treatment of oropharyngeal cancer. TORS is a valid treatment for selected patients with oropharyngeal cancer.

Transoral robotic surgery for hypopharyngeal squamous cell carcinoma: 3-Year oncologic and functional analysis

The recent trend in treatment of hypopharyngeal cancer is organ preservation in order to maintain swallowing and speech function as well as improve quality of life. Transoral robotic surgery (TORS) can remove hypopharyngeal lesions successfully without an external incision, preserving physiologic functions of affected organs. However, studies have yet to assess the oncologic and functional results of TORS for the treatment of hypopharyngeal cancer. This prospective study evaluated the oncologic and functional results of TORS for the treatment of hypopharyngeal cancer obtained at our institution over a period of 3 years and confirmed the validity of TORS as a surgical organ-preserving strategy. Between April 2008 and September 2011, 23 patients who were diagnosed with hypopharyngeal cancer underwent TORS for removal of a primary lesion. The da Vinci Robotic system (Intuitive Surgical Inc., Sunnyvale, California) was used to remove the lesion. The Kaplan-Meier method was used to analyze overall survival and disease-free survival. Videopharyngogram study (VEF) was performed and functional outcome swallowing scale (FOSS) was utilized to measure and evaluate swallowing function. Acoustic wave form analysis was conducted to evaluate voice status. Overall survival at 3 years was 89% and disease-free survival was 84%. On the VEF study, serious aspiration or delay of swallowing was not observed during the pharyngeal stage of the swallowing process. Overall, 96% of the patients showed favorable swallowing abilities with an FOSS score ranging from 0 to 2. The fundamental frequency variation (vF0) and jitter were increased upon acoustic waveform analysis (vF0=2.71 ± 0.063, Jitter=2.01 ± 0.034), but the harmonic-to-noise ratio (HNR) and shimmer were maintained close to the normal range (HNR=1.28 ± 0.001, Shim=1.74 ± 0.036). The oncologic and functional results of TORS were quite acceptable for the treatment of hypopharyngeal cancer. TORS is a valid treatment option as a surgical, organ-preserving strategy for select patients with hypopharyngeal cancer.

The oncologic safety and functional preservation of supraglottic partial laryngectomy

Objective The purpose of this study was to evaluate the appropriateness of the conservative surgery as the initial treatment of supraglottic cancer by the comparative study of supraglottic partial laryngectomy with radiation therapy. Methods We analyzed 48 patients diagnosed as having supraglottic cancer who underwent supraglottic partial laryngectomy and 20 patients treated with radiation therapy as initial treatment from 1991 to 2005. Oncologic safety was evaluated by comparison of survival rates. Swallowing test was performed with videoesophagofluoroscopy under the category of the pharyngeal phase and the presence or absence of aspiration. Phonologic analysis was performed with acoustic waveform analysis and stroboscopy. Results Positive resection margin was observed in 12 of the patients who received supraglottic partial laryngectomy (SPL), and its relationship with the primary subsite was evaluated. For the patients in stages I and II, the overall survival rate in each of the SPL group and the radiotherapy (RTx) group was 87% and 80%, respectively. For the patients in stages III and IV, the overall survival rate was 87% and 80%, respectively. On evaluation of swallowing and phonation function, no significant difference was noted between the SPL group and the RTx group. Conclusion This study suggests that for patients with supraglottic cancer, SPL provides acceptable survival, swallowing, and phonologic results in comparison with radiation therapy.

African Englishes: acoustic analysis of vowels

ABSTRACT: This paper focuses on acoustic analysis of African English (AfrE) vowels produced by a controlled sample of speakers from Kenya, Ghana, and Zimbabwe. Adopting quantitative methods of data sampling and analysis, and holding dialectal factors as homogeneous as possible, this exploratory study subjects Schmied's (1991a) claim – that a major source of regional variation is the ‘deviation’ in the production of RP central vowel [] (as in bird) – to empirical scrutiny. Schmied contends that [] backs and lowers to [] in West African English, fronts and lowers to [a] or fronts to [e] in East African English, while in (Black) South African English it fronts to [e]. However, analysis of acoustic waveforms of AfrE vowels, produced by educated speakers of Bantu and Kwa languages, partially corroborate Schmied's contention. For instance, Ghanaian and Zimbabwean respondents in this study front the RP vowel [] to [e], while Kenyans lower it to [a]. The paper provides a methodological framework that will at least address some research concerns voiced over the years: lack of “objective, systematic study” (Abdulaziz 1991: 393), “deficiency in methodology” (Adegbija 1994: 53), and “overgeneralization” (Simo Bobda 2000: 264). Sustained empirical studies could eventually lead to a fresh perspective on AfrE's phonological variation.

The Role of Selected Lexical Factors on Confrontation Naming Accuracy, Speed, and Fluency in Adults Who Do and Do Not Stutter

The purpose of this study was to investigate whether lexical access in adults who stutter (AWS) differs from that in people who do not stutter. Specifically, the authors examined the role of 3 lexical factors on naming speed, accuracy, and fluency: word frequency, neighborhood density, and neighborhood frequency. If stuttering results from an impairment in lexical access, these factors were hypothesized to differentially affect AWS performance on a confrontation naming task. Twenty-five AWS and 25 normally fluent comparison speakers, matched for age and education, participated in a confrontation naming task designed to explore within-speaker performance on naming accuracy, speed, and fluency based on stimulus word frequency and neighborhood characteristics. Accuracy, fluency, and reaction time (from acoustic waveform analysis) were computed. In general, AWS demonstrated the same effects of lexical factors on their naming as did adults who do not stutter. However, accuracy of naming was reduced for AWS. Stuttering rate was influenced by word frequency but not other factors. Results suggest that AWS could have a fundamental deficit in lexical retrieval, but this deficit is unlikely to be at the level of the word's abstract phonological representation. Implications for further research are discussed.

Attenuation analysis of acoustic waveforms in a borehole intercepted by a sand-shale sequence reservoir

We applied a new processing algorithm to extract intrinsic attenuation (1/Q) from the head P-wave of a full waveform sonic log. The sonic log was acquired in an oil reservoir in northeast Texas (USA). The reservoir is a sand-shale sequence characterized at the pore, core, and borehole scales. We found that the attenuation correlates with the lithology, including a sandstone zone partially saturated with oil and water. A comparison of 1/Q with the microseismogram and the petrophysics of other well logs provides a way of evaluating the consistency of Q at each borehole depth location. An analysis of the results explains the different attenuation anomalies found in the Q log.

Investigation of interfaces with analytical tools

This paper focuses on advancements in three areas of analyzing interfaces, namely, acoustic microscopy for detecting damage to closely spaced interfaces, thermal imaging to detect damage and degradation of thermal interface materials and laser spallation, a relatively new concept to understand the strength of interfaces. Acoustic microscopy has been used widely in the semiconductor assembly and package area to detect delamination, cracks and voids in the package, but the resolution in the axial direction has always been a limitation of the technique. Recent advancements in acoustic waveform analysis has now allowed for detection and resolution of closely spaced interfaces such as layers within the die. Thermal imaging using infrared (IR) thermography has long been used for detection of hot spots in the die or package. With recent advancements in very high-speed IR cameras, improved pixel resolution, and sophisticated software programming, the kinetics of heat flow can now be imaged and analyzed to reveal damage or degradation of interfaces that are critical to heat transfer. The technique has been demonstrated to be useful to understand defects and degradation of thermal interface materials used to conduct heat away from the device. Laser spallation is a method that uses a short duration laser pulse to cause fracture at the weakest interface and has the ability to measure the adhesion strength of the interface. The advantage of this technique is that it can be used for fully processed die or wafers and even on packaged devices. The technique has been used to understand interfaces in devices with copper metallization and low-k dielectrics.

Application of acoustic full wavetrains for the determination of lithology, reservoir and mechanical parameters of formation1

AbstractThe significant development in acoustic full waveform logging during the last ten years has made it increasingly possible for log analysts to determine the physical properties of a rock formation in situ.Parallel to the methods applied to a single wavetrain during seismic processing, the new techniques, used for sets of wavetrains, have been successfully tested with acoustic full waveforms. Instantaneous characteristics analysis is included in this group of methods. This approach, leading to qualitative and quantitative interpretation, reveals the influence of small changes in physical properties on acoustic full wavetrains.Applications of complex acoustic waveform analysis for the determination of inhomogeneous zones are presented. Colour diagrams of instantaneous characteristics are used for the detection of fractured regions and slow formations with increased attenuation of acoustic waves.Results of the interpretation of individual acoustic full waveforms, based on cross‐correlation and spectral analysis, using the IDNP and IDNS computer programs, e.g. velocities of compressional waves, shear and Stoneley waves, are presented. Since the bulk density of the rocks was known, it was possible, using the velocities of P‐ and S‐waves obtained, to calculate the dynamic elastic moduli. We used the interpretation of acoustic full wavetrains to calculate porosity. The sonic porosity is compared to the porosity obtained from other logs and to that obtained from core sample analysis.The examples of acoustic full wavetrains were recorded in the Miocene sulphur‐bearing limestones in central Poland. Field measurements were made using the domestic prototype equipment for well log recordings in shallow boreholes.

COMPARISON OF THE EFFECTS OF THE LARYNGEAL MASK AIRWAY AND ENDOTRACHEAL INTUBATION ON VOCAL FUNCTION

We have compared changes in vocal function produced after insertion of a laryngeal mask airway (LMA) with those produced by tracheal intubation in 20 patients. Using acoustic waveform analysis, we computed amplitude variability (AV), pitch variability (PV), harmonics-to-noise ratio (HNR) and additive noise level (ANL) before anaesthesia and at 1, 4, and 24 h after tracheal extubation. There were no significant changes in vocal function after extubation except for HNR ratio (P = 0.046) at 4 h in the LMA group. There were differences in all four variables at 1 h, 4 h, or both, after tracheal extubation compared with baseline in the tracheal tube group. In both groups, all variables were the same as baseline values 24 h after extubation. We observed significant differences in AV (4 h), PV and ANL (1, 4 h) values between the two groups. These observations suggest that the LMA causes less vocal change than tracheal intubation.

Study of KBr/Pb(NO 3) 2 growth and crystal morphologies by acoustic emission and photomicrographic techniques

Simultaneous optical and acoustic information was used to elucidate the mechanism of acoustic emission (AE) generation during growth of pure and Pb(NO 3) 2 doped KBr crystals. The mechanism of generation is postulated as one of inter-crystal interaction. The use of AE for monitoring the growth of different crystal structures was examined by studying different KBr morphologies grown with varying degrees of Pb dopant (0–32000 ppm). The AE profiles collected during the crystal growth of the dendritic form of KBr (4080–8120 ppm Pb dopant), and the doped forms of 12210 ppm Pb and above were found to give the best agreement with the image whitening profiles collected simultaneously. The dendritic form of KBr observed between 4080 and 8120 ppm consisted of finger-like outgrowths, that spread outwards from the evaporating droplet. Scanning electron microscopy showed these fingers to consist of contiguous chains of tiny (< 25 μm) octahedra, a microscopic structure that provided many potential sources of emission. The total AE observed during the growth of the different KBr morphologies was found to vary in a reproducible manner over 60 experiments. The mass of crystals grown was less than 0.12 g for all samples. Acoustic waveform analysis showed that these signals arising during growth were distinguishable from artificially produced signals of bulk dendrite fracture and crystal impact.

Auditory space expansion via linear filtering

A signal-processing algorithm that modifies the interaural time delays associated with directional sources is described. Signals received at two microphones are processed by four linear filters arranged in a lattice configuration to produce two outputs, one for each ear. Since the processing is linear, the method is equally applicable to single or multiple directional sources. The filters are designed to minimize the average squared error between a user specified desired space warping function and the actual warping function that they implement. Two classes of filters are considered: filters whose frequency response is unconstrained and filters constrained to be causal with finite impulse response. In both cases the solution of the least-squares problem is given and properties of the actual space warping function are examined. Perceptual experiments and analysis of acoustic waveforms are utilized to demonstrate the effectiveness of the algorithm. Extension of this method for utilizing more than two microphones is described.

Does short-term endotracheal intubation affects the acoustic characteristics?

Endotracheal intubation can produce various degrees of temporary and sometimes permanent damage to the laryngotracheal mechanism. Recent development of computer based voice analysis technology can now detect a minute changes in acoustic waveforms which a normal human ear cannot. In the study we compared and analyzed the acoustic waveforms of 35 patients undergoing surgery under intubation anaesthesia. The aim of the present series is to analyze the effects of short term intubation with computerized voice laboratory. Values of acoustic waveforms obtained from 35 patients were compared 48 hours after the short term endotracheal intubation anaesthesia. The comparisons were made in terms of perturbation (jitter and shimmer), harmonic- to noise ratio (HNR) and fundamental frequency (F0). The pre-intubated voice characteristics when compared with the post-intubation group did not reveal any statistical difference (P>0.05). However, there was only a minimal decrease in F0. The study revealed that, short term intubation anaesthesia does not alter the acoustic characteristics. The analysis of acoustic waveforms is a non invasive technique that helps to evaluate the effects of tracheal intubation on laryngeal function, a technique that warrants further evaluation.