• Phonetics and Speech Sciences
• /
• v.15 no.1
• /
• pp.35-45
• /
• 2023

Tohoku Japanese is known to have voiced stops without pre-voicing in word-initial position, whereas traditional or conservative Japanese has voiced stops with pre-voicing in the same position. One problem with this devoicing of voiced stops is that it affects the distinction between voiced and voiceless stops because their voice onset time (VOT) values overlap. Previous studies have confirmed that Tohoku speakers use post-stop fundamental frequency (F0) as an acoustic cue along with VOT to avoid overlap. However, the role of post-stop F0 as a perceptual cue in this region has barely been investigated. Therefore, this study explored the role of post-stop F0 in stop voicing perception along with VOT. Several perception tests were conducted using resynthesized stimuli, which were manipulated along a VOT continuum orthogonal to an F0 continuum. The results showed no significant regional difference (Tohoku vs. Chubu) for nonsense words (/ta-da/). However, for meaningful words (/pari/ 'Paris' vs. /bari/ 'Bali,' /piza/ 'pizza' vs. /biza/ 'visa'), a significant word effect was found, and it was confirmed that some listeners utilized the post-stop F0 more consistently and steadily than others. Based on these results, we discuss innovative listeners who may lead the change in the perception of stop voicing.

• Phonetics and Speech Sciences
• /
• v.14 no.4
• /
• pp.67-75
• /
• 2022

This study compared voice range profiles (VRPs) of modal and falsetto register in 53 dysphonic and 53 non-dysphonic adult women with gliding vowel /a/'. The results shows that maximum fundamental frequency (F0_MAX), maximum intensity (I_MAX), F0 range (F0_RANGE), and intensity range (I_RANGE) are lower in the dysphonic group than in the non-dysphonic group. F0_MAX and F0_RANGE are significantly higher in falsetto register than modal register in both groups. I_MAX and I_RANGE are significantly higher in falsetto register in the non-dysphonic group, but those are not different between two registers in the dysphonic group. There was no statistically significant difference in minimum F0 (F0_MIN) and minimum intensity (I_MIN) between the two groups. Modal-falsetto register transition occurred at 378.86 Hz (F4#) in the dysphonic group and 557.79 Hz (C5#) in the non-dysphonic group, which was significantly lower in the dysphonic group. It can be seen that both modal and falsetto registers in dysphonic adult women are reduced compared to non-dysphoinc adult women, indicating that the vocal folds of dysphonic adult women are not easy to vibrate in high pitches. The results of this study would be the basic data for understanding the acoustic features of voice disorders.

• Phonetics and Speech Sciences
• /
• v.14 no.4
• /
• pp.45-56
• /
• 2022

This paper proposes an optimal methodology for automatically diagnosing and predicting the severity of the chronic kidney disease (CKD) using patients' utterances. In patients with CKD, the voice changes due to the weakening of respiratory and laryngeal muscles and vocal fold edema. Previous studies have phonetically analyzed the voices of patients with CKD, but no studies have been conducted to classify the voices of patients. In this paper, the utterances of patients with CKD were classified using the variety of utterance types (sustained vowel, sentence, general sentence), the feature sets [handcrafted features, extended Geneva Minimalistic Acoustic Parameter Set (eGeMAPS), CNN extracted features], and the classifiers (SVM, XGBoost). Total of 1,523 utterances which are 3 hours, 26 minutes, and 25 seconds long, are used. F1-score of 0.93 for automatically diagnosing a disease, 0.89 for a 3-classes problem, and 0.84 for a 5-classes problem were achieved. The highest performance was obtained when the combination of general sentence utterances, handcrafted feature set, and XGBoost was used. The result suggests that a general sentence utterance that can reflect all speakers' speech characteristics and an appropriate feature set extracted from there are adequate for the automatic classification of CKD patients' utterances.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.12
• /
• pp.67-76
• /
• 2006

The reasonable assessment of the shear stiffness of a dredged soft ground and soft clay is difficult due to the soil disturbance. This study addresses the development and application of a new in-situ shear wave measuring apparatus (field velocity probe: FVP), which overcomes several of the limitations of conventional methods. Design concerns of this new apparatus include the disturbance of soils, cross-talking between transducers, electromagnetic coupling between cables, self acoustic insulation, the constant travel distance of S-wave, the rotation of the transducer, directly transmitted wave through a frame from transducer to transducer, and protection of the transducer and the cable. These concerns are effectively eliminated by continuous improvements through performing field and laboratory tests. The shear wave velocity of the FVP is simply calculated, without any inversion process, by using the travel distance and the first arrival time. The developed FVP Is tested in soil up to 30m in depth. The experimental results show that the FVP can produce every detailed shear wave velocity profiles in sand and clay layers. In addition, the shear wave velocity at the tested site correlates well with the cone tip resistance. This study suggests that the FVP may be an effective technique for measuring the shear wave velocity in the field to assess dynamic soil properties in soft ground.

• Korean Journal of Environmental Biology
• /
• v.40 no.1
• /
• pp.25-53
• /
• 2022

In this study, trends in research methods and topics of seabird and marine fish migration were examined. Based on the framework of existing animal migration studies, future research directions were proposed in relation to the migration of seabirds and fish. In terms of research methodology, with the development of science and technology, tracking techniques using radio telemetry, acoustic telemetry, RFID (radio-frequency identification), satellite tracking, and geolocators are widely used to study seabird and fish migration. Research is also conducted indirectly through a population survey and the analysis of substances in the body. Research contents are largely classified into extrinsic factors that affect migration(such as environmental variables and interspecific competition), intrinsic factors such as hormones, anthropogenic activities including fishery and offshore wind farm, and the effect of global climate change. In future studies, physiological factors that influence or cause migration and dispersal should be identified concerning intrinsic factors. For the analysis of migration ability, it is necessary to study effects of changes in the magnetic field on the migration ability of seabirds and fish, interspecific differences in spatiotemporal migration ability, and factors that influence the migration success rate. Regarding extrinsic factors, research studies on effects of anthropogenic disturbances such as fishery and offshore wind farm and global climate change on the migration and dispersal patterns of marine animals are needed. Finally, integrated studies on the migration of seabirds and fish directly or indirectly affecting each other in various ecological aspects are required.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.43 no.3
• /
• pp.321-335
• /
• 2023

Monitoring sediment loads in natural rivers is the key process in river engineering, but it is costly and dangerous. In practice, suspended loads are directly measured, and total loads, which is a summation of suspended loads and bed loads, are estimated. This study proposes a real-time sediment discharge monitoring system using the horizontal acoustic Doppler current profiler (H-ADCP) and support vector regression (SVR). The proposed system is comprised of the SVR model for suspended sediment concentration (SVR-SSC) and for total loads (SVR-Q_TL), respectively. SVR-SSC estimates SSC and SVR-Q_TL mimics the modified Einstein procedure. The grid search with K-fold cross validation (Grid-CV) and the recursive feature elimination (RFE) were employed to determine SVR's hyperparameters and input variables. The two SVR models showed reasonable cross-validation scores (R²) with 0.885 (SVR-SSC) and 0.860 (SVR-Q_TL). During the time-series sediment load monitoring period, we successfully detected various sediment transport phenomena in natural streams, such as hysteresis loops and sensitive sediment fluctuations. The newly proposed sediment monitoring system depends only on the gauged features by H-ADCP without additional assumptions in hydraulic variables (e.g., friction slope and suspended sediment size distribution). This method can be applied to any ADCP-installed discharge monitoring station economically and is expected to enhance temporal resolution in sediment monitoring.

• The Journal of Korean Institute of Next Generation Computing
• /
• v.13 no.6
• /
• pp.96-105
• /
• 2017

In this paper, we investigated the age classification from the speaker by analyzing the voice calls of the emergency center. We classified the adult and elderly from the call center calls using behavioral speech utterances and SVM(Support Vector Machine) which is a machine learning classifier. We selected two behavioral speech utterances through analysis of the call data from the emergency center: Silent Pause and Turn-taking latency. First, the criteria for age classification selected through analysis based on the behavioral speech utterances of the emergency call center and then it was significant(p <0.05) through statistical analysis. We analyzed 200 datasets (adult: 100, elderly: 100) by the 5 fold cross-validation using the SVM(Support Vector Machine) classifier. As a result, we achieved 70% accuracy using two behavioral speech utterances. It is higher accuracy than one behavioral speech utterance. These results can be suggested age classification as a new method which is used behavioral speech utterances and will be classified by combining acoustic information(MFCC) with new behavioral speech utterances of the real voice data in the further work. Furthermore, it will contribute to the development of the emergency situation judgment system related to the age classification.

• Science of Emotion and Sensibility
• /
• v.25 no.4
• /
• pp.129-138
• /
• 2022

In the context of the increasing applications of voice assistants in vehicles, we focused on the association between the visual appeal of the cars and the acoustic characteristics of the voice assistants. This study aimed to investigate the relationship between the visual appeal of the vehicle and the voice assistant based on their emotional characteristics. A total of 15 adjectives were used to assess the emotional characteristics of 12 types of cars and six types of voices. An online interview was carried out, instructing participants to match three adjectives with the presented car images or voices. This was followed with a brief interview to allow the participants to reflect on the adjective matches. Based on the assessments, we performed principal component analysis (PCA) to determine factors. We aimed to deploy the cars and voices and analyze the patterns of clustering. The PCA analysis revealed two factors profiled as "Light-Heavy" and "Comfortable-Radical." Both car and voice stimuli were deployed in a two-dimensional space showing the internal relationship within and between the two substances. Based on the coordination data, a hierarchical cluster grouped the 18 stimuli into four groups labeled as challenge, elegance, majesty, and vigor. This study identified two latent factors describing the emotional characteristics of both car images and voice types clustered into four groups based on their emotional characteristics. The coherent matches between car style and voice type are expected to address the design concept more successfully.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.230-230
• /
• 2020

하천 유량측정을 위한 표면유속계는 비접촉식 방식이기 때문에 현장에서의 측정이 간편하고, 비교적 안전하기 때문에 홍수시 유량측정에 널리 이용되고 있다. 비접촉식 유속계가 가지고 있는 이러한 장점으로 전자파표면유속계의 활용이 점차 증가하고 있으며, 영상유속계와 같은 비접촉 측정방식의 활용방안 마련에 대한 연구개발 등이 꾸준히 진행되어 왔다. 최근에는 고정식으로 상시 운영이 가능한 표면유속계 등이 출시되어 소규모 하천이나 수로에서의 상시 유량측정에 활용되고 있다. 다만, 이러한 비접촉식 유속계는 표면의 유속을 측정하기 때문에 유량산정을 위해서는 평균유속으로의 환산이 필요하지만, 현재까지는 평균유속 환산계수를 사용하여 표면유속을 평균유속으로 환산하는 방법이 유일하게 활용되고 있다. 하지만, 실제 하천에서는 단면 및 하도형태, 하상조건, 수리특성 및 유속분포 등의 다양한 조건에 따라 환산계수가 결정되기 때문에 이를 단순히 일률적으로 적용하는 것은 곤란하며, 이로 인해 과거 오랫동안 표면유속을 평균유속으로 환산하기 위한 다양한 연구가 진행되었지만, 실제 다양한 조건의 하천에 적용할 수 있는 표준화된 방법은 아직까지 제시되지 못하고 있다. 현재까지, 고정식으로 설치된 유속계로부터 측정된 유속을 평균유속으로 환산하는 방법으로는 국내외적으로 지표유속법(Index Velocity Method)과 유속분포법(Velocity Profile Method)이 대표적이며, H-ADCP (Horizontal-Acoustic Doppler Velocity Profiler) 또는 UVM(Ultrasonic Velocity Meter) 등과 같은 초음파유속계를 활용한 자동유량측정시설의 유량산정방법으로 활용되고 있다. 이러한 방법들은 고정된 유속계의 측정유속을 지표유속(V_i)으로 하여 다양한 범위의 실측된 평균유속과의 관계를 개발하여 활용하거나, 지표유속을 매개로 개수로 단면의 이론적인 유속분포를 추정하여 평균유속을 산정한다. 이러한 지표유속을 활용하는 방법들에서 공통적으로 중요한 것은 하천단면의 최대유속(V_max)이 가장 좋은 지표유속이라는 것이다. 따라서 국제기준에서는 지표유속을 측정하는 유속계의 가장 바람직한 위치로 유심부(core flow)를 권장하고 있다. 하지만, 접촉식 유속계의 경우 유심부 설치가 매우 어렵고 많은 비용이 들기 때문에, 비접촉식 유속계를 활용하여 하천단면의 최대유속을 측정할 수 있다면, 가장 효율적인 고정식 측정방법이 될 수 있을 것이다. 따라서, 본 연구에서는 비접촉식 표면유속계의 고정식 유량측정 활용성 및 적용성을 검토할 목적으로 표면유속에 대한 유량산정방법을 검토하였다. 이를 위해 24GHz의 주파수를 갖는 레이다표면유속계인 Sensoflow를 낙동강 수계 길안천에 위치한 안동시(대사3교)에 고정설치하여 표면유속을 지표유속으로 수집하였다. 다양한 유량규모에서 측정한 실측 표면유속과 수집된 표면유속을 지표유속으로 활용하여 지표유속관계를 개발하였으며, 산정된 유량을 기존 수위-유량관계곡선식의 환산유량과 비교하여 표면유속의 지표유속 활용성을 검토하였다.

• Steel and Composite Structures
• /
• v.46 no.1
• /
• pp.53-73
• /
• 2023

Man-made structure materials like concrete usually contain inclusions. These inclusions affect the mechanical properties of concrete. In this investigation, the influence of inclusion length and inclination angle on three-dimensional failure mechanism of concrete under uniaxial compression were performed using experimental test and numerical simulation. Approach of acoustic emission were jointly used to analyze the damage and fracture process. Besides, by combining the stress-strain behavior, quantitative determination of the thresholds of crack stress were done. concrete specimens with dimensions of 120 mm × 150 mm × 100 mm were provided. One and two holes filled by gypsum are incorporated in concrete samples. To build the inclusion, firstly cylinder steel tube was pre-inserting into the concrete and removing them after the initial hardening of the specimen. Secondly, the gypsum was poured into the holes. Tensile strengths of concrete and gypsum were 2.45 MPa and 1.5 MPa, respectively. The angle bertween inclusions and axial loadind ary from 0 to 90 with increases of 30. The length of inclusion vary from 25 mm to 100 mm with increases of 25 mm. Diameter of the hole was 20 mm. Entirely 20 various models were examined under uniaxial test. Simultaneous with experimental tests, numerical simulation (Particle flow code in two dimension) were carried out on the numerical models containing the inclusions. The numerical model were calibrated firstly by experimental outputs and then failure behavior of models containing inclusions have been investigated. The angle bertween inclusions and axial loadind vary from 0 to 90 with increases of 15. The length of inclusion vary from 25 mm to 100 mm with increases of 25 mm. Entirely 32 various models were examined under uniaxial test. Loading rate was 0.05 mm/sec. The results indicated that when inclusion has occupied 100% of sample thickness, two tensile cracks originated from boundaries of sample and spread parallel to the loading direction until being integrated together. When inclusion has occupied 75% of sample thickness, four tensile cracks originated from boundaries of sample and spread parallel to the loading direction until being integrated together. When inclusions have occupied 50% and 25% of sample thickness, four tensile cracks originated from boundaries of sample and spread parallel to the loading direction until being integrated together. Also the inclusion was failed by one tensile crack. The compressive strength of samples decease with the decreases of the inclusions length, and inclusion angle had some effects on that. Failure of concrete is mostly due to the tensile crack. The behavior of crack, was affected by the inclusion length and inclusion number.