• Journal of Computing Science and Engineering
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• 제7권2호
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• pp.112-121
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• 2013

The last years have seen a rise of interest in using electroencephalography-based brain computer interfacing methodology for investigating non-medical questions, beyond the purpose of communication and control. One of these novel applications is to examine how signal quality is being processed neurally, which is of particular interest for industry, besides providing neuroscientific insights. As for most behavioral experiments in the neurosciences, the assessment of a given stimulus by a subject is required. Based on an EEG study on speech quality of phonemes, we will first discuss the information contained in the neural correlate of this judgement. Typically, this is done by analyzing the data along behavioral responses/labels. However, participants in such complex experiments often guess at the threshold of perception. This leads to labels that are only partly correct, and oftentimes random, which is a problematic scenario for using supervised learning. Therefore, we propose a novel supervised-unsupervised learning scheme, which aims to differentiate true labels from random ones in a data-driven way. We show that this approach provides a more crisp view of the brain states that experimenters are looking for, besides discovering additional brain states to which the classical analysis is blind.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.94-101
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• 1998

This paper presents the psychoacoustic analyses on the vehicle interior, noise generated when accelerating. Following the objective quantification for vehicle noises of different classes, the subjective decision process by the jury test is adopted to interrelate these results based on two different approaches. In particular, the paired comparison method is employed in assessing the sound quality in terms of the quietness, the powerfulness, and the pleasantness of the human auditory sensation. Special attention is paid to the physical interpretation of psychoacoutic parameters and their interrelation to the subjective assessment scores. In order to ensure the integrity of statistics of the survey, various tests are performed. The results show that the consistency of the "quiet" sensation is far higher than that of the "powerful" and the "pleasant" sensations. Also, it is found that the most significant parameter determining these feelings turns out to be the inherent loudness of the noise instead of the conventional indicators such as the weighted sound pressure level. It may be concluded that the psychoacoustic analysis offers more realistic evaluation for vehicle noise and assists the improvement of NVH more efficiently.ement of NVH more efficiently.

• 한국음향학회지
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• 제20권7호
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• pp.3-12
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• 2001

본 연구에서는 소리에 대한 주관적 평가 인자 중 하나인 러프니스 계산 모델을 구현하였다. 구현된 러프니스 모델은 기존 모델의 고찰을 통해 계산 모델을 구체화하였으며, 주파수 영역으로부터 상호 상관 인자를 구하는 방법 등을 이용하여 계산 효율 및 정확도를 향상시켰다. 또한 기존의 주관적인 러프니스 평가치와의 비교를 통해 구현된 모델의 유용성을 확인하였다. 한편 기존 모델 및 구현된 러프니스 계산 모델을 통해 얻을 수 있는 러프니스 스펙트럼이 주파수 영역에서의 슬롭 가진(slope excitation)의 영향으로 인해 실제 변조되는 주파수 대역을 탐색하기 어려운 점을 발견하고, 구현된 모델의 상관 인자 계산 부분을 실제 변조가 발생하는 임계 대역에서만 러프니스 스펙트럼 값이 존재하도록 수정하여, 러프니스 기여성분의 탐색이 보다 용이해진 방법을 제안하였다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 추계학술대회
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• pp.147-150
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• 1995

최근의 마취과학에 관한 연구에 있어서의 주된 경향은 마취심도 및 의식수준의 결정을 신경생리학적인 관점에서 분석하고자 하는 것이다. 즉, 마취와 의식에 관한 인간의 뇌가 가지고 있는 기능이나 약리학적인 반응을 대표할 수 있는 생체신호를 검출, 분석하여 정량화하고 이들을 이용하면 마취심도 및 의식수준과의 큰 상관관계를 얻을 수 있을 것이라 가정하는 것이다. 본 연구에서는 청각유발전위 (LAEP, Long latency Auditory Evoked Potential)를 검출하여 추출된 변수들과 마취제 투여량간의 변화에 따른 상관성을 분석하고자 하였다. 수술환자(17명)를 대상으로 실험을 실시하였으며 마취제로서는 Midazolam과 Diazepam을 인체로 투여하고 1 KHz와 2 KHz의 청각자극을 제시하였을 때 피검자로부터 발생되는 LAEP를 검출하였다. 검출된 LAEP로부터 추출된 N100과 P300의 진폭은 마취량의 증가에 따라서 간소함을 알 수 있었으며, 이러한 유의한 상관성을 보이는 진폭의 변화는 마취제의 투여에 따른 의식수준의 변화를 나타내는 지수(index)의 설정 및 알고리듬의 수립에 이용될 수 있을 것이다.

• 한국간호교육학회지
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• 제19권4호
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• pp.684-692
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• 2013

Purpose: This study attempted to discover the effects of distraction on the hospitalized children's fear of the hospital and needle-related pain. Methods: The experimental group was given visual stimulation using a character from the injection room entrance. In addition, the video recording of 'bambarabam' was provided for visual and auditory stimulation to distract the children. The research tools included the hospital-related fear scale, Faces Pain Rating Scale (Wong & Baker, 1988) and Procedure Behaviour Check List (Lebaron&Zeltzer, 1984). For statistical analysis, the SPSS 19.0 program was used on the collected data for $X^2$-test and Mann-Whitney U test. Results: The experimental group showed significantly less fear ofthe hospital compared to the control group (U=151.50, p=.024). The experimental group showed significantly lower pain on both Faces Pain Rating Scale (U=167.50, p=.043) and the Procedure Behaviour Check List (U=106.00, p=.001) compared to the control group. Conclusion: These results suggest that distraction was effective in reducing the child's fear of the hospital and injection pain.

• 말소리와 음성과학
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• 제5권3호
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• pp.39-46
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• 2013

This study examined the perception of two Korean vowels using F1/F2 manipulated synthetic vowels. Previous studies indicated that there is an overlap between the acoustic spaces of Korean /o/ and /u/ in terms of the first two formants. A continuum of eleven synthetic vowels were used as stimuli. The experiment consisted of three tasks: an /o/ identification task (Yes-no), an /u/ identification task (Yes-no), and a forced choice identification task (/o/-/u/). ROC(Receiver Operating Characteristic) analysis and logistic regression were performed to calculate the boundary criterion of the two vowels along the stimulus continuum, and to predict the perceptual judgment on F1 and F2. The result indicated that the location between stimulus no.5 (F1 = 342Hz, F2 = 691Hz) and no.6 (F1 = 336Hz, F2 = 700Hz) was estimated as a perceptual boundary region between /o/ and /u/, while stimulus no.0 (F1=405Hz, F2=666Hz) and no.10 (F1=321Hz, F2=743Hz) were at opposite ends of the continuum. The influence of F2 was predominant over F1 on the perception of the vowel categories.

• 한국소음진동공학회논문집
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• 제24권3호
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• pp.253-260
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• 2014

conducted. In-situ measurements were conducted to investigate the noise characteristics in high-speed trains such as KTX and KTX-Sancheon. Binaural microphones and spherical microphone were adopted to record and evaluate the spectral characteristics and noise incidence characteristics at the seats in the passenger cars. Environmental elements were also recorded during the noise measurements using a camcorder and GPS application. In addition, auditory tests were conducted to investigate annoyance of interior noise of high-speed trains. Based on the objective measure and subjective responses on interior noise, statistical analysis such as correlation and regression analyses were carried out. From the results perception models for evaluating the interior noise of high-speed train were derived.

• Child Health Nursing Research
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• 제23권4호
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• pp.494-504
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• 2017

Purpose: The aim of this study was to analyze Neonatal Intensive Care Unit nurses' behaviors while soothing newborns with bronchopulmonary dysplasia. Methods: An observational study was used to assess nurses' soothing behaviors. Data were collected from September, 2012 to March, 2013 using an audio-video recording system. Participants were eight babies and 12 nurses caring for those babies. After obtaining parental permission, the overall process of each episode from nurses' engagement in soothing to the end of soothing was recorded. Then a researcher interviewed each participating nurse. Data from 18 episodes were transcribed as verbal and nonverbal nursing behaviors and then categorized by two researchers. Results: There were 177 observed soothing behaviors which were classified with the five sensory-based categories (tactile, oral, visual, auditory, vestibular). Most frequently observed soothing behavior was 'Gently talking' followed by 'Removing irritant', and 'Providing non-nutritive sucking'. Nurses' perceived soothing behaviors were similar to the observed soothing behaviors except for 'Gently talking'. Conclusion: Nurses used diverse and mixed soothing behaviors as well as recognizing those behaviors as essential nursing skills. Nurses' soothing behaviors identified in this study can be used to comfort babies and to enhance their developmental potential in accordance with individual characterstics or cues.

• 대한의용생체공학회:의공학회지
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• 제26권4호
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• pp.199-205
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• 2005

When recording single-unit responses from neural systems, a common problem is the accurate detection of spikes (action potentials) in the presence of competing unwanted (noise) signals. While some sources of noise can be readily dealt with through filtering or 'template subtraction' techniques, other sources present a more difficult problem. In particular, noise components introduced by power supplies, which contain harmonics of the power-line frequency, can be particularly troublesome in that they can mimic the shape of the desired spikes. Thus, standard 'template subtraction' techniques or notch-filtering approaches are not appropriate. In this study, we propose the use of a novel template-subtraction scheme that involves estimating the power-line noise waveform and using cross-correlation techniques to subtract them from the recordings. This technique requires two key steps: (1) cross-correlation analysis of each recorded waveform extracts a robust representation of the power-line noise waveform and (2) a second level of cross-correlation to successfully subtract that representation from each recorded waveform. This paper describes this algorithm and provides examples of its implementation using actual recorded waveforms that are contaminated with these noise signals. An improvement (reduction) in the noise level is reported, as are suggestions for future implementation of this strategy.

• 한국소음진동공학회논문집
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• 제25권2호
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• pp.90-100
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• 2015

Recently, creating a signature sound for a brand has become more important in the automotive industry. It is important to remember that the people inside a vehicle are not the only one, who assess the signature sound, exhaust sound has become a more important factor. Most research has used psycho-acoustic parameter to objectively measure the aesthetic qualities of exhaust sound. However, these results do not parallel the results from subjective analysis. Therefore, this research focused on developing a method for objective quantification to assess the aesthetic qualities of exhaust sound in order to help develop a more appealing signature sound. To do so, the actual exhaust sound was synthesized and subjectively assessed at varied frequencies samples of 30 individuals employed at sejong R&D center. The results were analyzed using the science of harmony scale.