프랙탈 차원을 이용한 단음절 음성의 자$\cdot$모음 분리

최철영,김형순,김재호,손경식,Choi, Chul-Young,Kim, Hyung-Soon,Kim, Jae-Ho,Son, Kyung-Sik 한국음향학회 1994 韓國音響學會誌 Vol.13 No.3

본 논문에서는 음성신호의 프랙탈 차원을 이용하여 한국어 CV(Consonant-Vowel) 단음절에서 자음과 모음을 분리하는 실험을 하였다. 프랙탈 차원은 Minkowski-Bouligand 차원을 사용하였으며, 형태학적 커버링 (morphological covering) 방법을 이용하여 구하였다. 프랙탈 차원의 음성분리에 있어서의 유용성을 조사하기 위하여 프랙탈 차원과 단구간 에너지 각각을 이용한 음성분리 실험과 에너지와 프랙탈 차원을 같이 이용한 음성분리 실험을 하여 그 결과들을 비교하였다. 실험 결과 에너지의 기울기를 사용한 경우는 $88.0\%$의 바른 분리 결과를 보였고, 프랙탈 차원의 기울기를 사용한 경우는 그보다 더 나은 $93.6\%$의 바른 분리 결과를 보였으며, 에너지의 기울기와 프랙탈 차원의 기울기의 곱을 사용한 경우는 $96.1\%$로 가장 높은 바른 분리결과를 나타냈다. 이를 통해 프랙탈 차원이 음성신호의 분리에 있어서 하나의 유용한 파라메타가 될 수 있음을 확인하였다. In this paper, we performed a class of experiments on segmenting consonant and vowel from Korean consonant-vowel (CV) monosyllable data, using the fractal dimension of the speech signals. We chose the Minkowski-Bouligand dimension as the fractal dimension, and computed it using the morphological covering method. In order to examine the usefulness of the fractal dimension in speech segmentation we carried out speech segmentation experiments using the fractal dimension alone, using the short-time energy alone, and using both the fractal dimension and the short-time energy, and compared the results. From the experiments, segmentation accuracy of $96.1\%$ was achieved for the case with using the multiplication of the slope of the fractal dimension and that of the energy, while the segmentation accuracies for the cases with using the slope of either the fractal dimension or energy alone were slightly lower $(93.6\%)$ or much lower $(88.0\%)$ than the above case, respectively. These results indicate that the fractal dimension can be used as a good parameter for speech segmentation.

TMCP강의 용접 공정별 입열량에 따른 용접부 물성 평가 및 비교

최철영,지창욱,김형찬,남대근,김정돈,김순국,박영도,Choi, Chul Young,Ji, Chang Wook,Kim, Hyoung Chan,Nam, Dae-Geun,Kim, Joungdon,Kim, Soon Kook,Park, Yeong-Do 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.1

This paper has an aim to evaluate microstructure and fracture toughness of TMCP steel weldment applied for off-shore wind tower with the focus on the effect of heat input on the weldment with various welding processes; FCAW(13kJ/cm and 30kJ/cm), SAW(62kJ/cm), and EGW(177kJ/cm). Based on experimental results developed from this study, it was found that the impact toughness of top side for TMCP steel weldments with heat input up to 62 kJ/cm satisfied the required minimum value except the EGW(177kJ/cm). The heat input and microstructure are the main factors of impact toughness. The heat input of 13kJ/cm on back side with low heat input increased the amount of grain boundary ferrite which has low impact toughness, and heat input of 177kJ/cm on top side is significant enough to produce the austenite grain growth. The compositions and sizes of inclusions which are the dominant factors for the formation of acicular ferrite were analyzed by OM and EDS. As the heat input increased, the inclusions also grew and a nucleation site decreased. The size of nonmetallic inclusions and the crack width was nearly similar, therefore the inclusions were related with the crack propagation.

원자력간 현미경을 이용한 TRIP강 저항 점용접부의 미세조직 분석에 관한 연구

최철영,지창욱,남대근,장재호,김순국,박영도,Choi, Chul Young,Ji, ChangWook,Nam, Dae-Geun,Jang, Jaeho,Kim, Soon Kook,Park, Yeong-Do 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.1

The spot welds of Transformation Induced Plasticity (TRIP) steels are prone to interfacial failure and narrow welding current range. Hard microstructures in weld metal and heat affected zone arenormally considered as one of the main reason to accelerate the interfacial failure mode. There fore, detailed observation of weld microstructure for TRIP steels should be made to ensure better weld quality. However, it is difficult to characterize the microstructure, which has similar color, size, and shape using the optical or electron microscopy. The atomic force microscope (AFM) can help to analyze microstructure by using different energy levels for different surface roughness. In this study, the microstructures of resistance spot welds for AHSS are analyzed by using AFM with measuring the differences in average surface roughness. It has been possible to identify the different phases and their topographic characteristics and to study their morphology using atomic force microscopy in resistance spot weld TRIP steels. The systematic topographic study for each region of weldments confirmed the presence of different microstructures with height of 350nm for martensite, 250nm for bainite, and 150nm for ferrite, respectively.

접착제 경화시점에 따른 하이브리드 접합 파단모드 및 접합강도 평가

최철영,최원호,김준기,김종훈,박영도,Choi, Chul-Young,Saha, Dulal Chandra,Choi, Won-Ho,Kim, Jun-Ki,Kim, Jong-Hoon,Park, Yeong-Do 대한용접접합학회 2011 대한용접·접합학회지 Vol.29 No.6

With the development of pre-painted steel sheets for automotive body application, a new joining method is required such as hybrid joining with combination of adhesive bonding and mechanical joining. The objective of this study is to investigate the effect of pre- and post-baking of adhesive bonding on failure mode and strength of hybrid joining of automotive steel sheets. Experiments show that the hybrid joining exhibits better bonding strength and displacement than conventional adhesive joining and mechanical fastening each. Comparison of pre- and post-baked hybrid joining results suggested that baking at $160^{\circ}C$ after mechanical joining was found to have higher joining properties than pre-baking condition. The prebaking condition changed its fracture mode from interfacial to button fracture. The changes in fracture mode with post-baking of hybrid joining was attributed to variation in neck thickness and undercut of joint.

비파괴 계장화 압입시험을 이용한 저항 점용접부 물성 평가

최철영,김준기,홍재근,염종택,박영도,Choi, Chul-Young,Kim, Jun-Ki,Hong, Jae-Keun,Yeom, Jong-Taek,Park, Yeong-Do 한국분말야금학회 2011 한국분말재료학회지 (KPMI) Vol.18 No.1

Nondestructive instrumented indentation test is the method to evaluate the mechanical properties by analyzing load - displacement curve when forming indentation on the surface of the specimen within hundreds of micro-indentation depth. Resistance spot welded samples are known to difficult to measure the local mechanical properties due to the combination of microstructural changes with heat input. Particularly, more difficulties arise to evaluate local mechanical properties of resistance spot welds because of having narrow HAZ, as well as dramatic changed in microstructure and hardness properties across the welds. In this study, evaluation of the local mechanical properties of resistance spot welds was carried out using the characterization of Instrumented Indentation testing. Resistance spot welding were performed for 590MPa DP (Dual Phase) steels and 780MPa TRIP (Transformation Induced Plasticity) steels following ISO 18278-2 condition. Mechanical properties of base metal using tensile test and Instrumented Indentation test showed similar results. Also it is possible to measure local mechanical properties of the center of fusion zone, edge of fusion zone, HAZ and base metal regions by using instrumented indentation test. Therefore, measurement of local mechanical properties using instrumented indentation test is efficient, reliable and relatively simple technique to evaluate the tensile strength, yield strength and hardening exponent.

당뇨병 환자에서 방수흐림의 정량적 분석

최철영,이준용,김준모,박기호,이은정,Chul Young Choi,Jun Yong Lee,Joon Mo KimKi Ho Park,Eun Jung Rhee 대한안과학회 2008 대한안과학회지 Vol.49 No.12

Purpose: We performed quantitative analysis of aqueous flare to evaluate the influence of diabetes mellitus on the flare values reflecting microvascular injuries of the retina. Methods: We compared aqueous flare values of diabetic patients without diabetic retinopathy (80 patients, 160 eyes), with those of normal control group (21 persons, 42 eyes) and diabetic retinopathy patients (20 patients, 40 eyes). The correlation between flare values and the risk factors of diabetic retinopathy was evaluated in diabetic patients without diabetic retinopathy. Results: Flare values were highest in diabetic retinopathy patients, and higher in diabetic patients without diabetic retinopathy than normal control group with statistical significance (p<0.01). Flare values were not significantly correlated with the risk factors of diabetic retinopathy. Conclusions: Microvascular injury appears to be developed in diabetic patients without diabetic retinopathy.

컴퓨터그래픽스 기술을 이용한 효율적인 클레이 룩 애니메이션 제작 공정 구축 사례

최철영(Chul-Young Choi),김기홍(Ki-Hong Kim),최규돈(Kyu-Don Choi),채일진(Kyu-Don Choi) 한국애니메이션학회 2009 애니메이션연구 Vol.5 No.1

아이들뿐 아니라 어른들에게도 변함없이 사랑을 받고 있는 애니메이션의 표현기법들은 과학기술의 발달과 노동력의 가치향상에 의해 제작 방식의 변화가 요구되고 있다. 애니메이션 표현기법 중 클레이를 이용한 스톱모션 애니메이션은 제작기간이 길고 인력의존도가 높다. CG 기술을 도입하여 인력의존도를 낮추고 제작기간을 단축시켜 콘텐츠를 안정적으로 제작하기 위한 방법의 도입이 필요한 실정이다. 하지만 CG 기술만으로는 실사 클레이룩의 감성 도출이 쉽지 않기 때문에 실사 물체와 CG 캐릭터 간의 공간 속 공존을 통한 착시 효과가 필요하다. 클레이 배경 제작과 모션캡처를 적용한 캐릭터 애니메이션을 이용하여 클레이 룩 애니메이션을 만들기 위한 제작 공정을 알아보고 작업 효율을 높이기 위한 기술 개발을 통해 효율적인 애니메이션 제작을 위한 하나의 방향으로 제시하고자 한다. The constant interest and affection that have been shown by not only children but adults brings the issue of the expression techniques in animation that needs changes of production methods along the development of scientific technique and labor value. Stop-motion animation using clay, one of the representative methods of animation, requires long period of time for production and relies on human power as well. It brings us to the fact that it is necessary to come up with another method for a stabilized production of contents by shortening the production period and reducing the dependency of human power by importing Computer Graphics technique. However it is not a simple task to draw the sense of real clay-look animation with Computer graphics technique, and consequently it is very important to get a trick of the eye through coexistence between the real clay objects and Computer Graphics characters in one space. This study suggests an idea for effective animation production with its technique development to increase work efficiency after looking into the manufacturing process of clay-look animation using character animation that’s applied by motion-capture and background of real clay.

프로젝트식 수업을 위한 대학 애니메이션 교육모델 연구

최철영(Chul Young Choi),굴림(Qu Lin) 한국애니메이션학회 2013 애니메이션연구 Vol.9 No.2

스마트 어플리케이션(Smart application)을 통해 개인화된 생산과 소비가 가능해지는 시대가 도래함에 따라 전문화되고 세분화된 인력양성뿐 아니라 애니메이션 제작 공정을 잘 이해하고 전반의 과정을 수행할 수 있는 인력들이 요구되고 있다. 기존의 교육과정들은 3D 특성상 과목을 수행하기 위해 교수가 미리 준비한 준비물들을 이용하다 보니 학생들의 관심사와는 거리가 있어 학생들의 참여와 과제물의 완성도를 떨어트리는 원인이 되어 왔다. 이에 학생들이 좋아하는 웹툰의 형식을 빌려 학생들의 주변 아이디어를 발췌하여 스토리를 만들도록 하고 학생을 모티브로 개발한 캐릭터를 적용하여 애니메이션을 완성하게 함으로써 학생들의 관심과 참여를 극대화하는 교육내용을 만들어 보았다. 또한 발췌한 아이디어들로 2학기 이상 수업을 연계함으로서 개개인이 만든 아이디어가 다양한 콘텐츠로 산출될 수 있음을 증명하여 학생들이 애니메이션 전반의 제작능력을 갖출 수 있게 하고 완성도에 따른 성취감을 높여 보려 하였다. As the advent of an era of personalized production and consumption through smart applications become available, not only specialized and departmentalized manpower training system but also human resources that have a good understanding of animation production process and perform throughout the course of the workforce are required. The existing training courses has caused lowering the student participation and completion of assignments by using materials prepared in advance which has nothing to do with students’ interest in order to carry out the three-dimensional nature of the subject. As a way to solve the issue, this paper contains subject matter of what to maximize students’ interest and participation in the whole process by encouraging students to create their own unique stories drawing ideas around them, applying their computer-generated characters and completing animation in a format of WebToon that students’ prefer. In addition, it can provide a plan that helps students to be capable of managing overall process of producing animation and increases their sense of accomplishment for the degree of completion by demonstrating variety of content developed from their ideas for more than two semesters in a continuous stream.

도보관광에 참여하는 대학생들의 환경인식이 장소귀속감과 도보여행동기에 미치는 영향

최철영(Choi, Chul-Young),임진선(Lim, Jin-Sun) 한국웰니스학회 2018 한국웰니스학회지 Vol.13 No.3

이 연구는 도보관광에 참여하는 대학생들의 환경인식이 장소귀속감과 도보여행동기에 미치는 영향을 알아보는 것이 연구의 목적이다. 제주올레길에 방문하는 대학생들을 대상으로 유목적적표집 방법으로 250명에게 설문을 배포하였고, 불성실한 답변이나 제출되지 않은 설문지 20부를 제외한 230부를 이 연구에 사용하였다. 성별, 주거지역, 동반자, 참여횟수를 묻는 인구통계학적 문항과 환경인식, 장소귀속감, 도보여행동기를 묻는 리커트 척도 문항으로 구성하였다. 이 대상자들을 분석하기 위하여 빈도분석, 요인분석, 신뢰도분석, 상관관계, 회귀분석 방법을 사용하여 통계처리를 하였다. 그 결과 도보관광에 참여하는 대학생들의 환경인식이 장소귀속감에 긍정적 영향을 미쳤고, 도보관광에 참여하는 대학생들의 환경인식이 도보여행동기에 긍정적 영향을 미치는 것으로 나타났다. 이는 도보관광에서의 환경인식의 요인이 도보관광지의 장소귀속감을 높여주는데 긍정적 작용을 하고 있었다. 또한 이 환경인식은 참여자의 내재적 요소인 도보여행동기를 강화시켜주는 작용을 하고 있었다. 따라서 도보관광지역에서 환경인식을 할 수 있는 교육이나 광고 등의 마련이 필요가 있다. This study aims to study the effects of environmental awareness by college students who participate in road trip on their place attachment and walking-tour motivation. Data was collected through surveys on 250 college students visiting Jeju Olle Trail using purposive sampling method. 230 surveys, excluding 20 surveys with insincere or no response, were used for the study. The survey consisted of demographic questionnaires, including gender, place of residence, partner, and number of participation, and Likert scale questionnaires, including environmental awareness, place attachment, and walking-tour motivation. To analyze these subjects, they were statistically processed sing frequency analysis, factorial analysis, reliability analysis, correlation, and regression analysis methods. The result showed that environmental awareness by college students participating in road trip positively influenced walking-tour motivation. This was because environmental awareness at road trip was positively affecting enhancement of place attachment for road trip. Also, environmental awareness was reinforcing walking-tour motivation, an internal factor, by the participants. Consequently, there is a need for tourist regions to provide methods for enhancing environmental awareness, such as education or advertisement.

고강도 강판 저항 점용접부 강도 및 파단에 미치는 Paint Baking의 영향

최철영 ( Chul Young Choi ),이동윤 ( Dong Yun Lee ),김인배 ( In Bae Kim ),김양도 ( Yang Do Kim ),박영도 ( Yeong Do Park ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.12

Conventional fracture tests of resistance spot welds have been performed without consideration of the paint baking process in the automobile manufacturing line. The aim of this paper is to investigate the effect of the paint baking process on load carrying capacity and fracture mode for resistance spot welded 590 dual phase (DP), 780DP, 980DP, 590 transformation in duced plasticity (TRIP), 780TRIP and 1180 complex phase (CP) steels. With paint baking after resistance spot welding, the l-shape tensile test (LTT) and nano-indentation test were conducted on the as-welded and paint baked samples. Paint baking increased the load-carrying capacity of the resistance spot welded samples and improved the fracture appearance from partial interfacial fracture (PIF) to button fracture (BF). Improvement in fracture appearance after LTT is observed on weldments of 780 MPa grade TRIP steels, especially in the low welding current range with paint baking conditions. The higher carbon contents (or carbon equivalent) are attributed to the low weldability of the resistance spot welding of high strength steels. Improvement of the fracture mode and load carrying ability has been achieved with ferrite hardening and carbide formation during the paint baking process. The average nano-indentation hardness profile for each weld zone shows hardening of the base metal and softening of the heat affected zone (HAZ) and the weld metal, which proves that microstructural changes occur during low temperature heat treatment.