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이승훈,정원혁,최홍식,김수찬,임재중,김덕원,Lee, Seung Hoon,Jung, Won Hyuk,Choi, Hong-Shik,Kim, Soo-Chan,Im, Jae-Joong,Kim, Deok-Won 한국음성학회 2005 음성과학 Vol.12 No.4
Voice is made by systemic interaction of respiration, vocalization, articulation and resonation. There is no existing multi-channel voice analysis system to assess voice and respiration simultaneously. The most existing systems consist of. vocal fold vibration measurement such as stroboscopy, EGG (electroglottography) or laryngeal electromyography and voice analysis system. Since respiration has close relationship with voice simultaneous analysis of both vocal cord vibration and respiration are essential. In this study, a four channel integrated system are developed for acoustic analysis through microphone, vocal fold vibratory analysis using EGG, and respiratory analysis using two channel RIP (respiratory inductive plethysmography).
각종 음성분석기에 따른 음성장애 환자의 주기간 주파수 및 진폭변동률 분석
최성희,남도현,이승훈,정원혁,김덕원,최홍식,Choi Seong Hee,Nam Do-Hyun,Lee Seung-Hoon,Jung Won-Hyuk,Kim Deok-Won,Choi Hong-Shik 대한후두음성언어의학회 2005 대한후두음성언어의학회지 Vol.16 No.2
Background and Objectives : Voice perturbation measures, such as jitter and shimmer has been importantly used for diagnosis and treatment efficacy of laryngeal dysfunction. This study was conducted to investigate validity of newly developed multi-channel voice analyzer program by comparing with MDVP, PRAAT, TF32. In addition, we compared the voice perturbation measures with different voice analyzer program by type of signals. Materials and Methods : Nineteen mild-severe dysphonic patients participated in our study. Fundamental frequency, jitter and shimmer values were obtained from different voice analyzer program using the same sustained/ah/phonation. Results : Fundamental frequency and shimmer were highly correlated whereas jitter was weakly correlated between newly developed multi-channel voice analyzer program and the others though different pitch computation algorithm except MDVP, In addition, Type 2 and 3 signals were weakly correlated than Type 1. Conclusion : In the clinical setting, clinician may have sufficient information of voice analyzer and control conditions properly for severity of pathologic voice before voice perturbation measure to obtain reliable results.
패브릭 블레이드를 적용한 100W급 수직축 풍력발전기 개발
허영근(Young-Gun Heo),정원혁(Won-Hyuk Jung),정종현(Jong-Hyun Jeong) 한국산학기술학회 2023 한국산학기술학회논문지 Vol.24 No.10
본 논문은 패브릭을 이용한 100 W급 사보니우스형 수직축 소형 풍력발전기의 개발에 대한 내용이다. 패브릭 소재를 적용하여 블레이드 파손에 의한 사고를 예방하고 저속회전이 가능한 사보니우스형태를 적용하여 로터 회전에 의한 위협감을 줄이고자 하였다. 기본 설계를 통하여 로터의 형상 치수를 결정하고 유동해석을 통하여 정격 조건에서의 정격 출력을 확인하였다. 그리고 구조적 안전성을 고려하기 위하여 정격 출력 조건과 극한 조건에 대한 구조해석을 수행하였으며 정격 풍속 조건에서의 안전율은 30.4 이상, 극한 풍속 조건에서의 안전율은 10.5로 구조적 안전성을 확인하였다. 유동해석 결과, 106.8 W의 출력을 확인하였으며 이를 토대로 풍력발전기 로터를 제작하였다. 풍동시험을 통하여 로터의 출력을 검증하였으며 개선된 로터의 풍동 시험 결과는 107.9 W가 나타남을 확인하였다. This paper presents the development of a 100 W Savonius small VAWT (Vertical Axis Wind Turbine) using fabric blades. The aims were to prevent accidents caused by blade damage using fabric material and enable low-speed rotation by adopting the Savonius-type rotor, reducing the hazards associated with rotor rotation. The dimensions of the rotor were determined through the basic design. Computational Fluid Dynamics (CFD) confirmed the rated power output under rated operating conditions. In addition, structural analysis was performed for both rated wind speed conditions and extreme wind speed conditions to assess the structural safety. The safety factors were 30.4 or higher at rated wind speed conditions and 10.5 at extreme wind speed conditions, confirming the structural integrity. The CFD results confirmed the power output of 106.8 W. The wind turbine rotor was manufactured based on the CFD results. Wind tunnel testing was conducted to validate the rotor performance, and the wind tunnel test results from the improved rotor achieved 107.9 W.
액체의 표면 특성을 고려한 3차원 캐버티 내부의 스톡스 유동 특성 연구
허효원(Hyo Weon Heo),정원혁(Won Hyuk Jung),서용권(Yong Kweon Suh) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.5
In this study, a CFD code is developed to perform simulation of the surface and internal flow of a three-dimensional rectangular cavity driven by an external gas flow. Investigated in this study are surface characteristic such as surface tension, surface dilational viscosity(or surface elasticity), and surface viscosity. Visualization of the surface of water is performed to compare with the numerical results obtained with the developed in-house code. We have found that the surface flow is very sensitive to the surface tension and other configurations. The surface flow velocity obtained from the numerical solution is lower than the experimental result.
백석흠(Seok Heum Baek),정원혁(Won Hyuk Jung),강상모(Sangmo Kang) 대한기계학회 2012 大韓機械學會論文集B Vol.36 No.12
이 논문은 선박에서 자세 안정용 양방향 축류펌프에 대한 임펠러 블레이드의 형상최적설계를 설명한 것이다. 양방향 축류펌프용 블레이드는 대칭형 익형을 사용하므로 효율이 기존의 단방향 축류펌프 보다 낮다. 이러한 양방향 축류펌프의 단점을 최소화 하고 효율을 증가시키기 위해 최적설계기법을 사용하였다. 양방향 축류펌프의 성능 개선을 위해 상용 CFD 프로그램인 ANSYS CFX v.13 을 이용하여 유동 해석을 수행하였다. 직교배열표, 분산분석과 직교다항식을 이용한 대리모델기반 최적설계방법은 최적 설계변수를 결정하고 주효과를 찾는데 사용하였다. 최적설계 결과로부터, 임펠러 블레이드의 유효한 설계변수를 확인하고 이의 최적해와 설계요구조건 만족에 대한 유용성을 설명하였다. This paper describes the shape optimization of impeller blades for an anti-heeling bidirectional axial flow pump used in ships. In general, a bidirectional axial pump has efficiency much lower than that of a classical unidirectional pump because of the symmetry of the blade type. In this study, by focusing on a pump impeller, the shape of the blades is redesigned to develop a bidirectional axial pump with higher efficiency. The commercial code employed in this simulation is CFX v.13. The CFD result of the pump torque, head, and hydraulic efficiency was compared. The orthogonal array (OA) and analysis of variance (ANOVA) techniques and surrogate-model-based optimization using orthogonal polynomials are employed to determine the main effects and their optimal design variables. According to the optimal design, we confirm an effective design variable for impeller blades and explain the optimal solution as well as the usefulness of satisfying the constraints of the pump torque and head.
3차원 캐버티 표면의 스톡스 유동 가시화 및 수치해석을 통한 표면 특성 연구
허효원(Hyo Weon Heo),이헌덕(Heon-deok Lee),정원혁(Won Hyuk Jung),조동식(Dong Sik Cho),서용권(Yong Kweon Suh) 한국가시화정보학회 2011 한국가시화정보학회지 Vol.9 No.3
?;?;In this study, we propose a method for characterizing fluid-mechanical properties of a fluid surface, such as surface dilatational and shear viscosity, by matching the flow visualization and the numerical simulation for a stokes flow in a three-dimensional cavity. The surface flow is driven by shear stress exerted on the free surface by an external gas flow. The external gas flow is simulated by using a commercial code, while the Stokes flow is calculated by an in-house code. We have found that the surface flow is very sensitive to the surface tension and other properties. The qualitative feature of the surface flow can be reproduced by the parameter tuning.