• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.127-130
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• 2003

In this paper, a hypothesis in order that the impulse response of a stable linear system does not change sign is suggested. For fixed zeros of the systems, the problem of synthesizing such a system is reduced to the problem of finding a proper denominator polynomial so that the step response of the overall system will not overshoot. The hypothesis is associated with the generalized time constant by Kim[5]. Under the hypothesis, we propose several methods that allow to compose a continuous time LTI systems achieving non-negative impulse response.

• 음성과학
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• 제1권
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• pp.153-200
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• 1997

In languages such as Japanese, it is very common to observe that short peripheral vowel are completely voiceless when surrounded by voiceless consonants. This phenomenon has been known as Montreal French, Shanghai Chinese, Greek, and Korean. Traditionally this phenomenon has been described as a phonological rule that either categorically deletes the vowel or changes the [+voice] feature of the vowel to [-voice]. This analysis was supported by Sawashima (1971) and Hirose (1971)'s observation that there are two distinct EMG patterns for voiced and devoiced vowel in Japanese. Close examination of the phonetic evidence based on acoustic data, however, shows that these phonological characterizations are not tenable (Jun & Beckman 1993, 1994). In this paper, we examined the vowel devoicing phenomenon in Korean using data from ENG fiberscopic and acoustic recorders of 100 sentences produced by one Korean speaker. The results show that there is variability in the 'degree of devoicing' in both acoustic and EMG signals, and in the patterns of glottal closing and opening across different devoiced tokens. There seems to be no categorical difference between devoiced and voiced tokens, for either EMG activity events or glottal patterns. All of these observations support the notion that vowel devoicing in Korean can not be described as the result of the application of a phonological rule. Rather, devoicing seems to be a highly variable 'phonetic' process, a more or less subtle variation in the specification of such phonetic metrics as degree and timing of glottal opening, or of associated subglottal pressure or intra-oral airflow associated with concurrent tone and stricture specifications. Some of token-pair comparisons are amenable to an explanation in terms of gestural overlap and undershoot. However, the effect of gestural timing on vocal fold state seems to be a highly nonlinear function of the interaction among specifications for the relative timing of glottal adduction and abduction gestures, of the amplitudes of the overlapped gestures, of aerodynamic conditions created by concurrent oral tonal gestures, and so on. In summary, to understand devoicing, it will be necessary to examine its effect on phonetic representation of events in many parts of the vocal tracts, and at many stages of the speech chain between the motor intent and the acoustic signal that reaches the hearer's ear.

• 문화기술의 융합
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• 제9권6호
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• pp.875-882
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• 2023

본 논문에서는 PID 알고리즘을 이용하는 온도제어기의 가상적 튜닝 기법을 제안한다. 제어대상의 수학적 표현을 이용하여 컴퓨터에서의 가상적 시뮬레이션을 활용하였다. 컴퓨터의 상세한 데이터 분석을 통하여 PID 알고리즘의 이득을 정확하게 구하는 기법을 도입하였고 기존의 실험적 튜닝 결과보다 우수한 성능을 검증하였다. 또한 실제의 제어대상에서 실시하는 튜닝 실험을 대체하는 장점이 있어 시간적 공간적 제한이 전혀 없다. 제어대상을 실제 가동하는 튜닝 실험은 그 과정에서 나타나는 자세한 데이터를 확인할 수 없다. 실험의 정확성을 보장할 수 없으며 그 결과를 즉시 확인할 수도 없었다. 제안하는 기법을 통해 튜닝의 모든 과정을 컴퓨터에서 정확하게 확인할 수 있으며 발생하는 문제의 원인도 분석할 수 있다.