• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.3 no.1
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• pp.6-12
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• 1989

Methods of voice rehabilitation in laryngectomees include training of esophageal speech, use of electrolarynx and pneumatic speech aid and surgical methods, etc. In this paper, we introduce the experimental model of obturator-type electrolarynx which has several advantages for use such as ease of learning, no disagreeable appearance, and both hands not being occupied. We compared it to normal voice and other voice rehabilitation methods such as esophageal voice, japanese pneumatic speech aid and cervical electrolarynx in intelligibility and sonagraphic evaluation. The results are as follows; 1) Obturator-type electrolarynx exhibited the lowest intelligibility. 2) In sonagraphic evaluation, the spectrogram produced by the obturator-type electrolarynx was the most different from those of normal voice.

• The Journal of the Acoustical Society of Korea
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• v.32 no.5
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• pp.423-429
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• 2013

The present study aimed to find the most sensitive placement of the skull to perceive speech through the bone vibrator in various protection methods while being exposed to noise. Twenty young normal-hearing adults (10 male and 10 female) participated in the study. As stimulus, Korean spondee words were presented via one of five skull locations (i.e., jaw angle, condyle, temple, mastoid, and vertex), while the participants wore one of four protection methods (i.e., ear form, ear plug, ear muff, and ear form and muff together) against white noise in one of four noise directions (i.e., 0, 90, 180, 270 degrees). The results showed: 1) there was a significant difference among the five skull locations with condyle being the most sensitive placement; 2) there was a significant difference among the four protection methods, with the ear form plus ear muff condition (or dual protection) providing the lowest threshold; 3) when exposed to noise from 90 degrees, the significantly lowest threshold was found; 4) there was no significant difference in results by gender. The pattern of results suggests that the communicative condition via the condyle bone conduction and the dual protection of the air conduction under any noise direction might be ideal for preventing noise-induced hearing loss, although further studies should be undertaken in this area.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.353-358
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• 2001

Since the financial crisis broke out, liquidity has become the critical issue in housing construction industry. In order to secure liquidity, it is prerequisite to precisely forecast cash flow. However, construction companies have failed to come up with a systematic process to manage and forecast cash flow. Until now, companies have solely relied on the prediction of profits and losses, which is carried out as they review business feasibility. To obtain more accurate cash flow forecast model, practical pattern of payments should be taken into account. In this theory, basic model that analyzes practical housing payment collection pattern resulting from prepayments and arrears is described. This model is to complement conventional cash flow forecast scheme in the phase of business feasibility review. Analysis result on final losses in cash that occur as a result of prepayment and arrears is considered in this model. Additionally, in the estimation of construction cost in the phase of business feasibility review, real construction prices instead of official prices are applied to enhance accuracy of cash outflow forecast. The proportion of payment made by a bill and changes in payment date caused by rescheduling of a bill are also factored in to estimate cash outflow. This model would contribute to achieving accurate cash flow forecast that better reflect real situation and to enhancing efficiency in capital management by giving a clear picture with regard to the demand and supply timing of capital.

• The Journal of the Acoustical Society of Korea
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• v.41 no.1
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• pp.108-113
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• 2022

Speech recognition in noise situation is an important skill for effective communication. Hearing In Noise Test (HINT) has been suggested as a clinical tool to evaluate these aspects. However, this tool has not been used widely in domestic clinics. In this study, psychophysical aspects of HINT and burdens in clinical application were analyzed to improve the applicability of the tool. The difficulty in understanding speech in the elderly population is due to hearing loss based on aging of peripheral and central auditory pathways. As typical clinical cases, HINT scores for young and elderly listeners (20s vs 70s) were compared. Four conditions of HINT test were Quiet (Q), Noise Front (NF), Noise Right (NR), and Noise Left (NL). Quantitative scores showed that the elderly listener required more Signal to Noris Ratio (SNR) values than the younger counterpart in noisy situations. Although both showed Binaural Masking Level Difference (BMLD) effect, the strength was smaller in the elder. However, the age-matched normalized data were not established in detail for clinical application. Confirmed usefulness of HINT and the related improvement in clinical measuring procedure were suggested.

• Journal of agricultural medicine and community health
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• v.48 no.1
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• pp.41-49
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• 2023

Objectives: To obtain audiologic basic data to diagnose the noise induced hearing loss of workers in fisheries. Methods: The charts of the referred fishermen with noise induced hearing loss from November 2022 to February 2023 at a general hospital were retrospectively reviewed. Pure tone audiometry, speech audiometry, auditory brainstem response test and auditory steady state response test were conducted. Results: All of them were men over 60 years of age, and the average duration of exposure to noise was 38.9 ± 10.8 years, and the average symptom duration of hearing loss was 13.4 ± 4.3 years. Although the hearing thresholds in the high frequencies were higher than thresholds in the low frequencies, the audiogram showed a down-sloping pattern without rebound at 8 kHz. 10.5% of the cases had thresholds greater than 75 dB in high frequencies, but 57.9% had thresholds greater than 40 dB in low frequencies. Other hearing test results of fishermen were similar to those of general noise-induced hearing loss. Conclusions: Although the fishermen were exposed to noise for a long time, they recognized hearing loss late. The hearing threshold in lower frequencies of the fishermen was higher than expected. Further studies will be needed to analyze the audiologic characteristics of noise-induced hearing loss of the fishermen after confirming noise exposure by conducting a survey on the working environment, such as the noise level and working hours.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.271-279
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• 2007

We suggest a novel method for the evaluation of cochlear implant (CI) speech processing strategy based on neural spike train decoding. From formant trajectories of input speech and auditory nerve responses responding to the electrical pulse trains generated from a specific CI speech processing strategy, optimal linear decoding filter was obtained, and used to estimate formant trajectory of incoming speech. Performance of a specific strategy is evaluated by comparing true and estimated formant trajectories. We compared a newly-developed strategy rooted from a closer mimicking of auditory periphery using nonlinear time-varying filter, with a conventional linear-filter-based strategy. It was shown that the formant trajectories could be estimated more exactly in the case of the nonlinear time-varying strategy. The superiority was more prominent when background noise level is high, and the spectral characteristic of the background noise was close to that of speech signals. This confirms the superiority observed from other evaluation methods, such as acoustic simulation and spectral analysis.

• The Journal of the Acoustical Society of Korea
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• v.19 no.2
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• pp.61-67
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• 2000

Recent progress in digital and VLSI technology has offered new possibility fer noticeable advance of hearing aids. Yet, environmental noise remains one of the major problems to hearing aid users. This paper describes results which speech recognition performance and speech discrimination performance was measured for listeners with sensorineural hearing loss, while listeners in speech-band noise. In addition, to ameliorate hearing-aided environments of hearing impaired listeners, environmental noise reduction using speech enhancement techniques are investigated as a front-end of conventional hearing aids. Speech enhancement techniques are implemented in a realtime system equipped with DSP board. The clinical test results suggest that the speech enhancement technique may work in synergy with gain functions fer the greater SNR improvement as the preprocessing algorithm of digital hearing aids.

• Journal of Biomedical Engineering Research
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• v.31 no.5
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• pp.385-394
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• 2010

Automatic gain control(AGC) is used in hearing aids to compensate for the hearing level as to reduced dynamic range. AGC is consisted of the main 4 factors which are compression threshold, compression ratio, attack time, and release time. This study especially focus on each individual need for optimum release time parameters that can be changed within 7 certain range such as 12, 64, 128, 512, 2094, and 4096ms. To estimate the effect of various release time in AGC, twelve normal hearing and twelve hearing impaired listeners are participated. The stimuli are used by one syllable and sentence which have the same acoustic energy respectively. Then, each of score of the word recognition score is checked in quiet and noise conditions. As a result, it is verified that most people have the different best recognition score on specific release time. Also, if hearing aids is set by the optimum release time in each person, it is helpful in speech recognition and discrimination.

• Journal of Biomedical Engineering Research
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• v.28 no.5
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• pp.694-702
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• 2007

The adaptation effect originating from the chemical synapse between auditory nerve and inner hair cell gives advantage in accurate representation of temporal cues of incoming speech such as speech onset. Thus it is expected that the modification of conventional speech processing strategies of cochlear implant(CI) by incorporating the adaptation effect will result in considerable improvement of speech perception performance such as consonant perception score. Our purpose in this paper was to evaluate our new CI speech processing strategy incorporating the adaptation effect by the observation of auditory nerve responses. By classifying the presence or absence of speech from the auditory nerve responses, i. e. spike trains, we could quantitatively compare speech onset detection performances of conventional and improved strategies. We could verify the effectiveness of the adaptation effect in improving the speech onset representation characteristics.

• KDI Journal of Economic Policy
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• v.17 no.4
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• pp.97-141
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• 1995

본고(本稿)는 우리 경제의 개방화(開放化) 자율화(自律化) 추세 속에서 거시경제정책수단(巨視經濟政策手段)으로서의 재정정책(財政政策)의 기능과 역할에 대해 다음의 두가지 방안을 제시하고 있다. 첫째로, 분기별(分期別) 통합재정통계(統合財政統計)를 이용한 실증분석 결과에 기초해서 안정적 경제운영(經濟運營)에 있어서 통합예산관리(統合豫算管理)의 중요성을 강조하였다. 분석결과, 기존의 연간자료를 이용한 분석에서 밝혀진 바와 같이 물가 상승률과 재정적자 변수간에 정(正)의 상관관계가 존재하는 것으로 나타났으며, 총통화 변수와 재정수지(財政收支)를 포함하는 물가상승률의 추정식 결과를 이용해서 단기적인 통화(通貨) 재정변수(財政變數)의 적정조합을 모색해 볼 수 있다. 다른 조건이 일정하다면 연간 총통화 증가율 1%포인트와 재정적자(財政赤字)의 대(對)GNP 비율 1%포인트 증가가 평균적으로 비슷한 정도의 물가압력을 낳는 것으로 나타난다. 둘째로, 효율적인 거시경제운영(巨視經濟運營)을 위해 요구되는 재정의 보다 근본적인 역할재정립 방향에 대해서 논의하였다. 해외자본유입(海外資本流入) 등에 대비하기 위해서는 신축적인 통화관리여건이 조성되어야 하고, 이를 위해서는 한은대출에 의한 정책금융 지원분의 재정이관 문제가 보다 적극적 전향적으로 검토되어야 한다. 총액한도대출대상 정책금융 중 지방중소기업자금의 이관문제가 검토되어야 하며, 상업어음할인, 무역금융, 소재 부품생산자금의 경우 기존의 중소기업지원관련 기금에 대한 출연을 확대해서 단기운전자금의 대출 등을 담당하게 하는 방안을 검토할 필요가 있다. 또한 총액한도대출대상 정책금융이 중소기업에 대한 지원인 점을 감안할 때, 중소기업부문(中小企業部門)에 대한 재정지원체계(財政支援體系)를 금리자유화 일정 등을 감안하여 종합적으로 정비함으로써 총액대출한도의 축소를 유도하는 역할을 재정이 담당해야 할 것이다.