• 대한기계학회논문집A
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• 제32권9호
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• pp.740-753
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• 2008

The conventional Split Hopkinson Pressure Bar (C-SHPB) technique with aluminum pressure bars to achieve a closer impedance match between the pressure bars and the specimen materials such as hot temperature degraded POM (Poly Oxy Methylene) and PP (Poly Propylene) to obtain more distinguishable experimental signals is used to obtain a dynamic behavior of material deformation under a high strain rate loading condition. An experimental modification with Pulse shaper is introduced to reduce the nonequilibrium on the dynamic material response during a short test period to increase the rise time of the incident pulse for two polymeric materials. For the dynamic stress strain curve obtained from SHPB experiment under high strain rate, the Johnson-Cook model is applied as a constitutive equation, and we verify the applicability of this constitutive equation to the probabilistic reliability estimation method. The methodology to estimate the reliability using the probabilistic method such as the FORM and the SORM has been proposed, after compose the limit state function using Johnson-Cook model. It is found that the failure probability estimated by using the SORM is more reliable than those of the FORM, and the failure probability increases with the increase of applied stress. Moreover, it is noted that the parameters of Johnson-Cook model such as A and n, and applied stress affect the failure probability more than the other random variables according to the sensitivity analysis.

• 한국음향학회지
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• 제20권3호
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• pp.56-62
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• 2001

본 논문에서는 손실이 발생하는 상황에서 높은 인식률을 유지하기 위해서 손실 데이터 이론을 음성 인식기에 적용하였다 손실 데이터 이론은 일반적으로 이용되는 통계적 정합 방법인 은닉 마코프 모델 (HMM: hidden Markov model) 중 연속 Gaussian확률 밀도 함수를 이용하여 음성 특징들의 출력 확률을 나타내는 경우에 쉽게 적용할 수 있다는 장점을 갖고 있다. 손실 데이터 이론의 방법 중 계산량이 적고 인식기에 적용이 쉬운 주변화(marginalization)방법을 사용하였으며 특징 벡터의 특정 차수나 시간열의 손실 검출 방법은 음성 신호의 에너지와 주위 배경 잡음의 에너지의 차이가 임계치보다 작게 되는 부분을 찾는 주파수 차감 방법을 이용하였다. 본 논문에서 제안한 손실 영역의 신뢰도 평가는 분석 구간이 모음일 확률을 계산해서 비교적 잉여 정보가 많이 포함된 모음화된 구간의 손실만을 처리하도록 하였다. 제안한 방법을 사용하여 여러 잡음 환경에 대해서 기존의 손실 데이터 처리 방법만을 사용한 경우보다 452 단어의 화자독립 단어 인식 실험을 수행한 결과 오류율측면에서 평균적으로 약 12％의 성능 향상을 얻을 수 있었다.

• 융합신호처리학회논문지
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• 제12권4호
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• pp.242-249
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• 2011

화면 내의 평면영역에서 투영변환행렬 대응 매칭법을 제안한다. 본 연구는 RANSAC에 있지만, RANSAC에서 랜덤 샘플링에 균일분포를 이용하는 것아 아니고, 화상의 특징점 위치나 템플리트 매칭의 차이로부터 구한 다중의 비균일 분포를 이용한다. 기존의 매칭법은 정대응이 거의 만족해야 할 조건을 이용하여 올바르다고 추정되는 대응을 샘플링하고, 그 대응을 1대 1로 매칭시켜 RANSAC을 행하였지만, 제안 방법에서는 화상으로부터 구한 다중의 확률 분포에서 단계적으로 샘플링함으로써 확률이 높은 정대응을 다중의 대응 후보 중에서 효율적으로 샘플링할 수 있다. 그 결과 최종적으로 수많은 정대응을 구할 수 있으며, 시뮬레이션과 실제 화상의 실험에 의하여 제안 방법의 유효성을 검증한다.

• 정보처리학회논문지B
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• 제10B권7호
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• pp.829-836
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• 2003

본 논문에서는 사전과 시소러스를 이용하여 문장음성 이해를 위한 확률모델을 제안한다. 제안한 확률모델은 입력되는 음성과 텍스트 문장에서 단어를 추출한다. 컴퓨터가 선택한 카테고리의 사전 DB와 입력된 문장에서 추출된 단어와 비교하고 확률모델로부터 확률값을 얻는다. 이때 컴퓨터로부터 상위어 정보를 알아내고 상위어 사전을 검색하여 단어를 추출하고 입력된 단어와 확률 모델을 비교하여 결과값을 얻는다. 사전과 상위어 사전으로부터 얻은 두개의 확률값을 더하고 그 값을 미리 정해진 임계값과 비교하여 문장의 이해도를 측정한다. 이와 같은 이해 시스템을 스무고개 게임에 적용시켜 그 성능을 평가 하였다. 상위어 확률 값($\alpha$)이 0.9이고 임계값 ($\beta$)은 0.38일 때 문장음성 이해의 정확도는 79.8%였다.

• 대한후두음성언어의학회지
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• 제8권1호
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• pp.59-64
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• 1997

In this Paper, we developed an electrolarynx controlled by the EMG(electromyography) of the sternohyoid muscle, and rested the property of the new electrolarynx while normal persons with his own larynx use it. for the examination of property of the developed electrolarynx, our researchers performed three different experiments. The first experiment was tested whether that on/off control of the vibrator of the electrolarynx is synchronized with the activity of the sternohyoid EMG. In the second experiment, it was tested when the lower amplitude of the sternohyoid EMG is produced, whether the higher pitch of the electrolarynx is produced, and vice versa. The third experiment was tested the probability that the electrolarynx can produce the voiceless sound. As the results, we found that the developed electrolarynx had the good produce of the on/off vibrator control and the pitch control of the electrolarynx. Also, we ascertained the possibility that it can produce the voiceless sound.

• 농촌계획
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• 제13권4호
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• pp.53-67
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• 2007

This study analyzed the probability that experiment stations, agricultural technology and extension centers, provincial agricultural research and extension services, central government organs, or civilian and other related organs will be the first choice of the compositional subjects of local innovation networks. While gender effect was statistically insignificant, educational level, income, main acquired information, sources of necessary information, and frequency of information acquisition sessions were significant, and the preference ranking model was highly relevant. According to the analysis, highly academic and business-related information was most likely to be acquired from the civilian sector; agricultural technology such as technology, crops/plants, storage, and circulation was most likely to be acquired from experiment stations and provincial agricultural research and extension services; and information on agricultural production was most likely to be acquired from agricultural technology centers.

• 말소리와 음성과학
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• 제5권1호
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• pp.91-98
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• 2013

This paper investigated Korean prosody as it relates to graded internal structure in an identification function. Within Korean prosody, variants regarded as dialectal variations can appear as different prosodic scales, which contain the range of within-category variations. The current experiment was intended to show how the prosodic scale corresponding to the range of within-category differences relates to f0 contours for speakers of two Korean dialects, North Kyungsang and South Cholla. In an identification task, participants responded by selecting an item from two answer choices. The probability of choosing the correct response from the two choices was computed by a logistic regression analysis using intercepts and slopes. That is, the correct response between two choices was used to show a linear line with an s-shape presentation. In this paper, to investigate the graded internal structure of labeling, 25%, 50%, and 75% of predicted probability were assessed. Listeners from North Kyungsang showed progressive variations, whereas listeners from South Cholla revealed random patterns in the internal structure of the identification function. In this paper, the results were plotted using scatterplot graphs, applying the range of within-category variation and predicted probability obtained from the logistic regression analyses. The scatterplot graphs showed the different degree of the responses for f0 scales (i.e., variations within categories). The results demonstrate that the gradient structures of native pitch accent users become more progressive in response to f0 scales.

• International Journal of Precision Engineering and Manufacturing
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• 제5권4호
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• pp.61-68
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• 2004

Necessity to address engineering system uncertainties in design processes has long been acknowledged. To obtain quality of product, a safety factor is traditionally used by many design engineers due to its easy of use and comprehension. However, the safety factor approach often yields either conservative or unreliable designs, since it ignores the type of probability distribution and the mechanism of uncertainty propagation from the input to the output. For a consistent reliability-based design, two fundamental issues must be investigated thoroughly. First, the design-decision process that clearly identifies a mechanism of uncertainty propagation under system uncertainties needs to be developed, which must be an efficient and accurate process. To identify the mechanism more effectively, an adaptive probability analysis is proposed by adaptively setting probability levels through a posteriori error estimation. The second is to develop the design process that not only yields a high quality design but also a cost-effective optimum design from manufacturing point of view. As a result, a response surface methodology is specially developed for RBDO, thus enhancing numerical challenges of efficiency and complicatedness. Side crashworthiness application is used to demonstrate the integrated design process for product and manufacturing process design.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제12권2호
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• pp.119-131
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• 2008

The paper considers the computation method in the performance evaluation of cellular network in the phase-type distribution assumptions that the channel holding times induced from mobility are modeled by well-fitted distributions to reflect an actual situation. When ww consider a phase-type distribution model instead of exponential distribution, the complexity of the computation increase exponential even though the accuracy is improved. We consider an efficient numerical algorithm to compute the performance evaluations in cellular networks such as a handoff call dropping probability, new call blocking probability, and handoff arrival rate. Numerical experiment shows that numerical analysis results are well approximated to the results of simulation.

• 제어로봇시스템학회논문지
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• 제10권9호
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• pp.763-770
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• 2004

The important issue of emotion recognition from speech is a feature extracting and pattern classification. Features should involve essential information for classifying the emotions. Feature selection is needed to decompose the components of speech and analyze the relation between features and emotions. Specially, a pitch of speech components includes much information for emotion. Accordingly, this paper searches the relation of emotion to features such as the sound loudness, pitch, etc. and classifies the emotions by using the statistic of the collecting data. This paper deals with the method of recognizing emotion from the sound. The most important emotional component of sound is a tone. Also, the inference ability of a brain takes part in the emotion recognition. This paper finds empirically the emotional components from the speech and experiment on the emotion recognition. This paper also proposes the recognition method using these emotional components and the transition probability.