• 말소리와 음성과학
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• 제4권3호
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• pp.129-136
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• 2012

Korean alveolar fricatives are late-developing speech sounds. Most previous research on phonemes used individual words or pseudo words to produce sounds, but word-level phonological analysis does not always reflect a child's practical articulation ability. Also, there has been limited research on articulation development looking at speech production by grammatical morphemes despite its importance in Korean language. Therefore, this research examines the articulation development and phonological patterns of the /s/ phoneme in terms of morphological types produced in children's spontaneous conversational speech. The subjects were twenty-two typically developing 3- and 4-year-old Koreans. All children showed normal levels in three screening tests: hearing, vocabulary, and articulation. Spontaneous conversational samples were recorded at the children's homes. The results are as follows. The error rates decreased with increasing age in all morphological contexts. Also, error percentages within an age group were significantly lower in lexical morphemes than in grammatical morphemes. The stopping of fricative sounds was the main error pattern in all morphological contexts and reduced as age increased. This research shows that articulation performance can differ significantly by morphological contexts. The present study provides data that can be used to identify the difficult context for articulatory evaluation and therapy of alveolar fricative sounds.

• 한국전기전자재료학회논문지
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• 제18권9호
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• pp.851-855
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• 2005

We investigated the unbalanced characteristics of the superconducting fault current limiters (SFCLs) based on YBCO thin films with a single line-to-ground fault. When a single line-to-ground fault occurred, the short circuit current of a fault phase increased about 6 times of transport currents after the fault onset but was effectively limited to the designed current level within 2 ms by the resistance development of the SFCL. The fault currents of the sound phases almost did not change because of their direct grounding system. The unbalanced rates of a fault phase were distributed from 6.4 to 1.4. It was found that the unbalanced rates of currents were noticeably improved within one cycle after the fault onset. We calculated the zero phase currents for a single line-to-ground fault using the balanced component analysis. The positive sequence resistance was reduced remarkably right after the fault onset but eventually approached the balanced positive resistance component prior to the system fault. This means that the system reaches almost the three-phase balanced state in about 60 ms after the fault onset at the three-phase system.

• 한국비블리아학회지
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• 제4권1호
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• pp.49-83
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• 1980

Rapid expansion has taken place in development of cooperative arrangements among libraries, in computerization, mechanization, and centralization of library services; in sizes of collections; and in the variety of services offered by libraries. These increasing complexities of library organizational arrangements and expansions in activities and services make it all the more important for libraries to define their objectives clearly and to have methods for measuring the level of attainment of these objectives. Libraries, as all other institutions and organizations, are faced with the economic problem of allocating their limited resources in such a manner as to generate maximum benefits and calculating the costs of a library. Furthermore, they should be able to measure their performance or degree of achievement of objectives. In order to it, it is essential to set a standard and review the time and motion study. This study is an attempt to build a general standard applicable to Korean university libraries to provide a persuasive basis to university library administrators in their work management: The usefulness of this study are given below. (1) It helps to balance available resources with estimated workload. (2) It helps in managing a library more efficiency and more economically (3) It helps in objective evaluation of individual employee performance and in evaluation of the organization as a whole. (4) It helps the librarian plan for financial and personnel needs on the basis of sound production figures.

• 음성과학
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• 제10권4호
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• pp.189-200
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• 2003

The objective of this study was to examine two new parameters by which we could screen people with malignant vocal folds. The new parameters were the difference sums and Pearson correlation coefficients between adjacent pairs of intensity level matrices of narrow-band spectra. Audio files from the Korean Disordered Speech Database were analyzed by Praat, a speech analysis software, to obtain matrices of 400 intensity levels at 16 time points of each sustained vowel spectra. We limited our study to 12 normal subjects and 20 patients with malignant vocal folds who recorded at least three Korean vowels at a sound-proofed booth in Busan National University Hospital. Results indicated that the average coefficients of the abnormal subjects were much lower than those of the normal subjects while the average difference sums of the patients were much higher than those of the normal ones. Also, we found that the degree of the malignancy of the vocal folds was related to the coefficients and sums. However, some subjects at the initial stages of cancerous vocal folds yielded almost comparable coefficients and difference sums to those of the normal speakers. Further studies on larger databases will be desirable to set certain criteria or threshold levels for screening people with vocal fold diseases.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.279-281
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• 2003

We analysed the operating properties of resistive type superconducting fault current limiters (SFCLs) based on YBCO thin films with a single line-to-ground fault. When a single line-to-ground fault occurred, the short circuit current of a fault phase increased up to about 6 times of transport currents immediately after the fault instant and was effectively limited to the designed current level within 2 ms by the resistance development of the SFCL. The fault currents of the sound phases almost did not change because of their direct grounding system. The unsymmetrical rates of a fault phase were distributed from 6.4 to 1.4. It was found that the unsymmetrical rates of currents were noticeably improved within one cycle after the fault instant. We calculated the zero phase currents for a single line-to-ground fault using the symmetrical component analysis. The positive sequence resistance was reduced remarkably right after the fault but eventually approached the balanced positive resistance component prior to the system fault. This means that the system reaches almost the three-phase symmetrical state in about 60 ㎳ after the fault. The ground currents were almost 3 times of the zero phase mts since most of the fault currents flowed through the grounding line.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.178-185
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• 2012

In Korea, researches on the exposure assessment of the hand-transmitted vibration started from the mid-90, however, they were performed in the limited industries such as auto-assembly plants and the evaluation of the vibration was mostly conducted by ISO 5349(1986). Therefore, it was necessary to assess hand-transmitted vibration levels of workplace such as ship building/repairing industry or mining industry where occupational injuries are largely occurred and to evaluate the vibration levels using revised ISO 5349(2001). The SVAN 949 Four Channels Sound & Vibration Analyser was used for the measurement. The workers using a chain saw were exposed to $1.7{\sim}2.8m/s^2$ of daily vibration level. Workers using a rock drill in a coal mining were exposed to the highest vibration acceleration among workers and the levels were $7.1{\sim}10.8m/s^2$. Vibration levels of grinders were different according to the types of grinders. The hand-transmitted vibration of 3 types of grinders were measured and the levels were $3.3{\sim}11.1m/s^2$. Workers using a impact wrench were exposed to $1.5{\sim}1.6m/s^2$ of vibration. Out of 20 kinds of machines, only 4 tools provided the information of vibration acceleration on the instructions. In addition, the current condition of workplaces to control vibration was not much different from the past because there are no vibration exposure limit.

• 한국소음진동공학회논문집
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• 제22권10호
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• pp.940-948
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• 2012

In Korea, researches on the exposure assessment of the hand-transmitted vibration started from the mid-90, however, they were performed in the limited industries such as auto-assembly plants and the evaluation of the vibration was mostly conducted by ISO 5349(1986). Therefore, it was necessary to assess hand-transmitted vibration levels of workplace such as ship building/repairing industry or mining industry where occupational injuries are largely occurred and to evaluate the vibration levels using revised ISO 5349(2001). The SVAN 948 Four Channels Sound & Vibration Analyser was used for the measurement. The workers using a chain saw were exposed to 1.7~2.8 $m/s^2$ of daily vibration level. Workers using a rock drill in a coal mining were exposed to the highest vibration acceleration among workers and the levels were 7.1~10.8 $m/s^2$. Vibration levels of grinders were different according to the types of grinders. The hand-transmitted vibration of 3 types of grinders were measured and the levels were 3.3~11.1 $m/s^2$. Workers using a impact wrench were exposed to 1.5~1.6 $m/s^2$ of vibration. Out of 20 kinds of machines, only 4 tools provided the information of vibration acceleration on the instructions. In addition, the current condition of workplace to control vibration was not much different from the past because there are no vibration exposure limit.

• 한국컴퓨터정보학회논문지
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• 제19권6호
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• pp.93-100
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• 2014

본 연구의 목적은170dB 이상의 고충격 소음원에서 실내 충격소음을 측정 평가 할 수 있는 측정시스템 구축 방법을 제안하는데 있다. 이러한 목적을 달성하기 위하여 실내충격소음 측정시스템용 시험장을 설계 및 구현하고, 충격소음 측정용 마이크로폰, Head & Torso Simulator, Ear Simulator를 구성하였다. 충격소음 측정 시 정확한 측정을 위하여 3가지 측정방법을 동시에 측정할 수 있도록 구현하였으며, 정확성과 신뢰성을 위하여 3가지의 실내충격소음 측정값을 상호 비교하였다. 3가지 측정방법에 따른 최대 음압레벨과 옥타브 밴드 결과를 비교 분석함으로써 실내 충격소음의 주파수 특성에 따른 차이점을 확인하였다. 이러한 결과는 반사파의 영향에 의한 것으로 판단된다. 이에, 시험장의 크기를 변형하면서 측정할 수 있도록 실내 충격소음 측정시스템을 구현하였다. 본 시스템 구현을 통하여, 충격 소음원의 특징분석과 해당 주파수별 스펙트럼의 반사파 영향들을 파악할 수 있을 것이며, 향후, 실내 충격소음에 대한 데이터 획득 및 분석을 위하여 유용하게 활용될 수 있을 것으로 판단된다.

• 디지털콘텐츠학회 논문지
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• 제11권2호
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• pp.235-242
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• 2010

음악제작에 쓰이는 음성합성엔진은 악기 소리와 음색의 합성에 머물던 과거의 신디사이저와는 달리, 인간의 목소리를 각 음소에 따라 샘플화하여 탑재함과 동시에 각 음소의 연결을 주파수 영역 내에서 자연스럽게 처리함으로써 실제 사람이 노래하는 것과 같은 수준까지 도달하게 되었다. 사용자들은 이러한 음성합성엔진을 음악제작에 국한하여 쓰지 않고 캐릭터를 활용한 콘서트, 영상제작, 음반, 모바일 서비스 등 2차 창작물로 새로운 음악의 형태를 창조하며 문화적 패러다임을 바꾸어 나가고 있다. 현재 음성합성엔진 기술은 악보 편집기를 통하여 사용자가 원하는 음과 가사, 그리고 음악적 표현 파라미터를 입력한 뒤, 실제 가성 샘플을 데이터베이스에서 가져와 합성엔진에서 발음들을 조합, 연결하여 노래하는 것을 가능하게 한다. 이러한 컴퓨터음악 기술의 발전으로 인해 파생된 새로운 음악 형태들은 문화적으로 큰 반향을 불러일으키고 있다. 이에 따라 본 논문은 구체적 활용 사례를 살펴보고 합성기술을 탐색함으로써, 사용자들이 음성합성엔진을 이해하고 습득하는 데 기여함과 동시에 그들의 다양한 음악제작에 도움이 되고자 한다.

• 한국음향학회지
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• 제19권1호
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• pp.25-31
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• 2000

이 논문에서는 직적법을 이용하여 반복법인 BFGS법의 초기값을 설정하는 알고리즘을 제안하고, 이를 이용하여 점배열음원 형태의 적응형 초음파 트랜스듀서의 최적 지향성합성을 시도했다. 이의 유효성을 확인하기 위하여 부엽의 레벨을 -30dB 이하로 제한한 임의의 빔폭을 갖는 준이상 빔, 회전 빔, 그리고 다중 빔을 보기로 하여 점배열음원으로 형성되는 2차원 음장내의 지향성합성 문제 및 복수의 주파수에 대한 적응 지향성합성 시스템의 적응성 문제를 검토하였다. 수치계산 결과, 제안한 방법은 BFGS법 단독에 의한 지향성합성보다 수렴속도가 빠르고, 목적 지향성합성을 위한 오차개선도 탁월하며, BFGS법과 같은 반복법에서 문제가 되는 초기치의 선택이 필요하지 않다는 장점도 있다. 또한, 제안법은 직접법 단독으로는 불가능한 적응제어도 가능하다.