• Communications for Statistical Applications and Methods
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• 제31권4호
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• pp.393-408
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• 2024

The sparse linear discriminant analysis can be incorporated into the penalized linear regression framework, but most studies have been limited to specific convex penalties, including the least absolute selection and shrinkage operator and its variants. Within this framework, concave penalties can serve as natural counterparts of the convex penalties. Implementing the concave penalized direction vector of discrimination appears to be straightforward, but developing its theoretical properties remains challenging. In this paper, we explore a class of concave penalties that covers the smoothly clipped absolute deviation and minimax concave penalties as examples. We prove that employing concave penalties guarantees an oracle property uniformly within this penalty class, even for high-dimensional samples. Here, the oracle property implies that an ideal direction vector of discrimination can be exactly recovered through concave penalized least squares estimation. Numerical studies confirm that the theoretical results hold with finite samples.

• 한국정보통신학회논문지
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• 제6권6호
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• pp.873-878
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• 2002

고정자 전류 스펙트럼(stator current spectrum)은 유도전동기의 고장 검출에 널리 사용되어왔다. 본 논문에서는 고정자 전류 스펙트럼 중에서 회전자 고장에 의해서 큰 영향을 받는 주파수 성분들로 특징벡터(feature vector)를 구성하고, 특징벡터와 기준벡터(reference vector)와의 평균 절대치 차이(mean absolute difference)를 구함으로써, 회전자 고장을 검출하는 방법을 제안한다. 제안한 방법에서는 전류 스펙트럼 중에서 추출된 매우 작은 크기(dimension)의 특징 벡터에 대한 평균 절대치 차이를 이용하기 때문에 신경회로망에 의한 고장 검출 알고리즘 둥에 비해서 훨씬 적은 계산량만으로 모터의 고장을 효율적으로 검출할 수 있다

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1144-1148
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• 1997

In this paper, a method for the daily maximum load forecasting which uses a chaotic time series in power system and artificial neural network. We find the characteristics of chaos in power load curve and then determine a optimal embedding dimension and delay time. For the load forecast of one day ahead daily maximum power, we use the time series load data obtained in previous year. By using of embedding dimension and delay time, we construct a strange attractor in pseudo phase plane and the artificial neural network model trained with the attractor mentioned above. The one day ahead forecast errors are about 1.4% for absolute percentage average error.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.578-580
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• 1995

In this paper, a method for the daily maximum load forecasting which uses a chaotic time series in power system and artificial neural network. We find the characteristics of chaos in power load curve and then determine a optimal embedding dimension and delay time, For the load forecast of one day ahead daily maximum power, we use the time series load data obtained in previous year. By using of embedding dimension and delay time, we construct a strange attractor in pseudo phase plane and the artificial neural network model trained with the attractor font mentioned above. The one day ahead forecast errors are about 1.4% of absolute percentage average error.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.835-837
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• 1996

In this paper, a method for the daily maximum load forecasting which uses a chaotic time series in power system and artificial neural network(Back-propagation) is proposed. We find the characteristics of chaos in power load curve and then determine a optimal embedding dimension and delay time. For the load forecast of one day ahead daily maximum power, we use the time series load data obtained in previous year. By using of embedding dimension and delay time, we construct a strange attractor in pseudo phase plane and the artificial neural network model trained with the attractor mentioned above. The one day ahead forecast errors are about 1.4% for absolute percentage average error.

• Journal of Astronomy and Space Sciences
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• 제21권4호
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• pp.263-274
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• 2004

한국천문연구원 보현산 천문대(Bohyunsan Optical Astronomical Observatory, BOAO)의 BOES(Bohyunsan Optical Echelle Spectrograph)를 이용하여 2003년 2월 26-27일 이틀간에 걸쳐 BX And의 고분산 관측을 수행하였다. 이 관측을 통하여 얻은 스펙트럼은 총 38개로 위상 $0.1{\sim}0.3$에 이르는 구간을 제외하고는 전위상에 걸쳐 골고루 관측이 이루어졌다. 시선속도를 구하기 위하여 BF(Broadening Function)와 CCF(Cross-Correlation Function)를 이용한 방법 이 모두 사용되었다. CCF를 이용하였을 때는 주성의 시선속도만을 얻은 반면, BF인 경우, 주성과 반성의 시선속도 모두를 잘 결정할 수 있었다. 새로운 시선속도곡선으로부터 주성과 반성의 최대 시선속도를 각각 $K_1=96.1km/s$와 $K_2=196.6km/s$으로 얻었으며, 이를 Bell et al.(1990)의 측광해와 결합하여 BX And의 절대 물리량을 새롭게 결정하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제25권4호
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• pp.371-374
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• 1999

상악협소증으로 인하여 골격관계의 수평적인 부조화와 부정 교합을 보인 상기환자의 경우 상악확대를 위해 구개확대장치를 이용하여 치료하였으나 원하는 치료결과를 얻을 수 없었다. 방사선 평가상 안면골의 봉합부골화가 이미 끝난 것으로 보여 외과적인 피질골절단술을 시행하였다. 외과적인 피질골절단술은 상악확대시 주위안면골의 저항을 줄이기 위한 목적으로 시행하는데 좋은 결과를 얻을 수 있었다. 술후 2주경과후와 12개월 경과후 교합관계 및 확대된 상악궁의 재발상태를 평가한 결과 술후 상태로 유지되고 있었다. 전반적인 교합상태도 많이 개선되어 있었다. 그러나 피질골절단술은 사전에 악궁의 형태나 길이, 수술방법의 선택, 술후 합병증에 대한 충분한 평가를 하여야 한다. 외과적인 피질골절단술은 치료비와 치료기간을 줄일 수 있고 술후 재귀가능성을 줄일 수 있다. 이에 본과에서 피질골절단술을 이용하여 양호한 결과를 얻었기에 본 학회지에 보고하는 바이다.

• 말소리와 음성과학
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• 제9권3호
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• pp.33-40
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• 2017

This study aimed to examine how Korean-English bilinguals make use of VOT and F0 cues in perception and production of Korean (lenis vs. aspirated) and English (voiced vs. voiceless) stops. It was explored whether bilinguals with extensive experience living in the U.S. exhibit native-like or interactive patterns in the cue use for both languages. Participants produced monosyllabic word-initial stops within a carrier sentence in each language, and performed forced-choice identification tasks with synthesized stimuli varying in 7 VOT steps and 7 F0 steps with base tokens of /$t^han$/ for Korean and /$t{\ae}n$/ for English. Listeners were required to select either /tan/ or /$t^han$/ for Korean and either /$d{\ae}n$/ or /$t{\ae}n$/ for English. The results from binary logistic regression analyses for each listener indicated that all bilinguals placed greater weight on F0 than VOT when distinguishing between the Korean lenis and aspirated stops, and greater weight on VOT than F0 in distinguishing between the English voiced and voiceless stops. In terms of production, all participants showed remarkably overlapping ranges in the VOT dimension and separating ranges in the F0 dimension for the stop contrast of Korean, while forming overlapping ranges in the F0 dimension and separating ranges in the VOT dimension for the stop contrast of English. These results indicate that the bilinguals with extensive exposure to L2 manage the stop systems of the two languages independently, both in perception and production, employing the opposite cue use for stops in the two languages. It was also found that the absolute beta-coefficient values of the perceptual cues for Korean stops were generally smaller than those for English and those reported in a previous study as for later bilinguals, which may have resulted from Korean not being their dominant language.

• 재활복지공학회논문지
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• 제9권2호
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• pp.129-135
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• 2015

본 연구에서는 3차원 영상처리와 노팅험 스케일을 이용하여 안면마비 평가 시스템을 개발하였다. 시스템은 측정부, 영상처리부, 연산부, 그리고 안면마비 평가 및 출력부로 구성되어 있다. 두 개의 웹캠을 사용하여 안면부의 8곳에 부착된 마커의 3차원 위치를 계산하였으며, 이를 이용하여 노팅험 스케일을 계산하고 화면에 보여준다. 피험자의 자세변화와 측정방식이 노팅험 스케일에 미치는 영향을 조사하였다. 측정방식은 2차원과 3차원을 비교하였으며, 피험자자세는 정면응시와 $11^{\circ}$ 측면응시를 비교하였다. 측면응시한 피험자를 2차원 방식으로 측정한 경우의 오차가 가장 컸다. 3차원 측정방식이 피험자의 자세변화에 따른 오차에 가장 덜 민감하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제39권
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• pp.15.1-15.7
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• 2017

Background: This study constructed a partial-least-square path-modeling (PLS-PM) model and found the pathway by which the postsurgical vertical dimension (VD) affects the extent of the final mandibular setback on the B point at the posttreatment stage for the skeletal class III surgery-first approach (SFA). Methods: This study re-analyzed the data from the retrospective study by Lee et al. on 40 patients with skeletal class III bimaxillary SFA. Variables were obtained from cone beam computed tomography (CBCT)-generated cephalograms. Authors investigated all variables at each time point to build a PLS-PM model to verify the effect of the VD on the final setback of the mandible. Results: From PLS-PM, an increase in $VD_{10}$ was found to decrease the absolute value of the final setback amount of the mandible, which reflects the postsurgical physiological responses to both surgery and orthodontic treatment, which, in turn, can be interpreted as an increase in postoperative mandibular changes. Conclusions: To resolve the issue of collinear cephalometric data, the present study adopted PLS-PM to assess the orthodontic treatment. From PLS-PM, it was able to summarize the effect of increased postsurgery occlusal vertical dimension on the increased changeability of the B point position at the posttreatment stage.