A study on improving bone conduction speaker performance by electromagnetic prediction and performance distribution by statistical analysis method

고동신,허덕재,박태원,이재혁 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4

The present paper is focused on the stochastic characteristics of the electromagnetic force, one of the performance parameters for the bone conduction speaker which is one of the devices in the “smart glass”. The design parameters were taken as significant, affecting the electromagnetic force. Characteristic analysis of significant parameters was considered by using the factorial design method. Significant factor of main effect was selected via fractional factorial design method. Main effect and interaction of selected factor were analyzed applying the full factorial design method. The independency of the selected parameter and their significant interaction were examined by using the F-test method. Linear and non-linear characteristics for the selected parameters and performance were examined by creation of the median point within the analysis results for significance analysis. Therefore, prediction model derived non-linear regression model from the central composite design of response surface method. For probability distribution of the electromagnetic characteristics, related prediction model and Monte Carlo simulation method were applied. Electromagnetic performance prediction result showed 98.5 % level and improved maximum 99.8 % reliability level under 3σ level of dimensional management. In view of this, such stochastic design approach could improve design efficiency via verification of individual design parameters’ effect on the performance levels, thereby proving design reliability based on the object levels.

위상 최적화 기법을 이용한 충격하중에 대한 차량 탑재형 전력변환장치의 마운트 경량화 설계

고동신,이현경,허덕재 한국전산구조공학회 2018 한국전산구조공학회논문집 Vol.31 No.6

In this study, it is describe to an optimization analysis process for the weight reduction of the voltage converter in the electric vehicle charging systems. The optimization design is a technique that finds the optimal material distribution under a given material quantity constraint by combining the design sensitivity with the material properties and the mathematical optimization. Among the topology optimization, a lightweight design is performed by a solid isotropic material with penalization with simple formula and well-convergence. The lightweight design consists of three steps. As a first step, a finite element model for the basic design of the on-board voltage converter was constructed and static analysis was performed on the load. In the second step, the optimum shape is obtained for the lightweight by performing the topology optimization using the solid isotropic material with penalization applying the stiffness coefficient of the isotropic material to the static analysis result. As a final step, impact analysis was performed by applying a half-sinusoidal pulse shape impact load which satisfies the impact test standard of the vehicle-mounted part with respect to the optimum shape. In the topology optimization, the design domain was defined as the mounting bracket area, and the design technology was finally achieved by optimizing the mounting bracket to achieve a weight reduction of 20% over the basic design. 본 연구는 전기자동차 충전시스템에서 전력변환장치의 경량화를 위한 최적화 분석프로세스에 대한 내용을 서술하였다. 최적화 설계는 재료 물성치에 대한 설계민감도와 수학적 최적화를 결합하여 주어진 재료량 제한조건 하에 최적의 재료분포를 찾는 설계기법으로 위상의 고정화, 자유도가 묶이는 문제 등을 해결할 수 있는 위상 최적화방법을 사용하였으며, 위상 최적화방법 중 비교적 수식화가 간단하고 수렴성이 좋은 SIMP법(solid isotropic material with penalization)에 의해 경량화 설계를 수행하였다. 경량화 설계는 3단계의 절차로 구성하였으며, 첫 번째 단계로 전력변환장치의 기본 설계에 대한 유한요소모델을 구성하고, 하중에 대한 정적해석을 수행하였다. 두 번째 단계로 정적해석 결과에 대해 등방성 재료의 강성계수를 적용한 밀도법을 이용하여 위상 최적화를 수행하여 경량화를 위한 최적 형상을 도출하였다. 세 번째 단계로 최적 형상에 대해 차량 탑재 부품의 충격시험기준에 만족하는 반정현파 펄스형태 충격하중을 인가하여 충격해석을 수행하였다. 위상 최적화단계에서 사용 환경조건으로 설계영역 정의는 마운팅 브래킷 영역으로 제한하였으며, 마운팅 브래킷의 설계 최적화를 통해 최종적으로 기본설계대비 20%이상의 경량화가 가능한 설계기술을 확보하였다.

새마을 운동의 참뜻

高東臣 건국대학교 1972 法經論叢 Vol.1972 No.7

水泳訓鍊이 體脂肪, 運動遂行 能力에 미치는 效果

高東信,兪承熙 경희대학교 체육과학연구소 1991 體育學論文集 Vol.19 No.-

The objective of this study is to ascertain the effects that swimming has on physical structure, physical strength, and athletic performance capacity. The traning group was composed of ten student members of the "K" University amateur swim team while the comparative group was composed of ten ordinary students. The training roup, with the exception of Sundays, trained for about an hour daily for a period of six weeks. In order to ascertain physical structure, the thickness of subcutaneous fat, percentage of bodyfat, and weight of body fat were measured. Finally, to ascertain the change in athletic performance capacity, heart rate, athletic endurance, and time till appearance of PWC170 were measured using a cycle ergometer. The first measurements were taken before the experiment. The second measurements were taken after three weeks. The last measurements were taken after six weeks. The following resurts were obtained after analyzing the measurement data. 1)The swimming group, as compared to the control group, decreased the thickness of subcetaneous fat, percentage of bodyfat. 2)Excecising abiligty time of the control group and the training group average (8.07, 8.22 min) at first, The control group averaged (3.97) rose and decreased (1.61%), but the swimming group's average was(1.22%) and continue rose (3.28%) after three, six weeks. 3)PWC 170 of the control group and the swimming group averaged (6.32, 6.30 min) at first. The control group averaged (1.90%) rose and decreased (-0.79), but the training group's average was(1.99%) and continue rose (5.11%) after three, six weeks. 4)General heart-beat of the control group and the swimming group averaged (72.20, 71.80 beat/min) at first. The control group averaged (0.55%) rose and decreased (-1.39) and continue decreased (-4.57) after three, six weeks. 5)The best heart-beat of the control group and the swimming group averaged (192.20, 191.60 beat/min) at first. The control group averaged (0.41%) rose and decreased (-0.52), but the swimming group's average was (-3.40) and continue decreased (-1.77) after three, six weeks. 6)The swimming group, as comparsed to the comparative group, showed a striking reduction in heart rate both during activity and at rest. Synthesizing the above result it is found that not only was the scope of the swimming group's improvement of physical strength comparatively large, but also that they showed reduction in body fat. Further more, their normal and maximum heartbeat, either active or at rest wast reduced. Finally, they both increased their athletic endurance and time till appearance of PWC170.

수평 및 수직 착자에 대한 햅틱 진동자의 진동특성에 관한 연구

고동신(Dong Shin Ko),허덕재(Deog Jae Hur),박태원(Tae Won Park),이재혁(Jai Hyuk Lee),이성수(Sung Su Lee) 대한기계학회 2015 大韓機械學會論文集A Vol.39 No.4

본 연구는 햅틱 진동자의 개발과정에 있어 성능인자의 단계별 설정절차와 성능 및 소형화를 위한 자석의 착자방법에 대한 연구를 수행하였다. 착자방법에 대한 연구는 수평착자와 수직착자의 구성방법에 따른 전자기력을 비교분석하여 수행하였으며, 수행결과 수평착자가 우수한 것으로 나타났다. 시스템적 설계 절차로는 제품의 특성으로부터 설계 인자를 설정하는 단계적 절차를 구성하여 시작품을 제작하고 시험을 통하여 검증하였다. 해석적 방법에서는 진동응답 특성 해석과 전기장의 해석을 독립적으로 수행하였으며, 시험결과와의 검증을 통해 잘 일치하는 결과를 도출하였다. 제품신뢰성 확보를 위한 신뢰성 기반 설계인자는 스프링 높이, 용접 위치, 코일의 위치로 선정하였다. 그리고 설계 인자에 따른 전자기장 민감도 및 성능 변화를 분석하였고 이를 바탕으로 신뢰성 기반의 고성능 햅틱 진동자를 구현할 수 있도록 설계방법을 제시하였다. This paper describes the study of the design procedure for the step-by-step setup parameters and of the magnetizing method for performance and size reduction in the development of a haptic vibrator. The study of magnetization was accomplished by comparing the electromagnetic force in accordance with the horizontal and the vertical magnetization. The theoretical results indicated that the horizontal magnetization resulted in a better performance. The systematic design of a step-by-step procedure for establishing the design parameters was verified by testing the characteristics of the fabricated prototype product. The vibration response function analysis and electric field analysis were processed by decoupling of the analytical method, and these were determined to be in good agreement with the test results. The design parameters to contributing to the product reliability included the spring height, the welding position, and the coil position. The sensitivity of the electromagnetic field and the performance change were analyzed based on the design parameters. As a result, we proposed a design method to implement a reliability-based, high performance haptic vibrator.

밸런스드 아마추어 초소형 스피커의 진동 및 음향특성 연구

고동신(Dong Shin Ko),허덕재(Duk Jae Hur),권상엽(Sang Yup Kwon),이성수(Sung Su Lee) 한국소음진동공학회 2016 한국소음진동공학회 논문집 Vol.26 No.1

This paper describes the development process for vibration and acoustic characteristics of a balanced armature speaker. The design parameters were chosen in consideration of the influence of the bending stiffness of balanced armature which is the form of a cantilever structure in the speaker. For study of the performance of the speaker according to the design parameters, in the first step, we analyzed the characteristics of the velocity of the diaphragm to the electrical input. Next step, acoustic characteristics were analyzed by structural-acoustic coupled analysis. And the reliability of the analysis was verified by comparing the result of analysis with test results. Finally, we proposed a design method for implementing an enhanced balanced armature speakers through analysis method.

다목적 고액분리 모듈의 여과판 형상 최적화를 위한 구조해석

정희숙,고동신,송형운 한국폐기물자원순환학회 2016 한국폐기물자원순환학회지 Vol.33 No.2

Purpose of this study is the design of the optimal membrane plate in filter press which is one of the devices for improving the solid-liquid separation through the mechanical dewatering of sewage sludge. We tried to improve durability of the membrane plate and efficiency of the filtrate drainage through the flow and structural analysis. Characteristics of specific pressure were also evaluated according to the shape of the membrane plate.

다목적 고액분리 모듈의 여과판 형상 최적화를 위한 구조해석

정희숙,고동신,송형운 한국폐기물자원순환학회 2016 한국폐기물자원순환학회지 Vol.33 No.2

Purpose of this study is the design of the optimal membrane plate in filter press which is one of the devices forimproving the solid-liquid separation through the mechanical dewatering of sewage sludge. We tried to improve durabilityof the membrane plate and efficiency of the filtrate drainage through the flow and structural analysis. Characteristics ofspecific pressure were also evaluated according to the shape of the membrane plate.

차량 시트 레일용 리드 스크류의 동역학적 해석을 통한 회전 토크 값 분석 연구

김석범,고동신 한국기계기술학회 2023 한국기계기술학회지 Vol.25 No.5

The objective of this study is to analyze the difference between the theoretically calculated torque values of lead screws used in vehicle seat rails and the required torque values due to various disturbances that occur in actual systems. Lead screws were classified into square and trapezoidal threads and modeled by two lead type. Dynamic analysis models were constructed by applying contact conditions and rotational joints between the lead screw and nut. The validity of the dynamic model was verified by comparing the torque values obtained from rigid body dynamic analysis with the theoretically calculated torque values. Then, the lead screw was modeled as a flexible body to investigate the torque variation required for the lead screw when dynamic loads are considered. This study will help predict the actual torque values of lead screws for seat rails.

실험 계획법 기반의 다이나믹 댐퍼를 이용한 자동차 시트 진동 저감 연구

김소울,남재현,고동신 한국자동차공학회 2023 한국 자동차공학회논문집 Vol.31 No.12

This study aims to mitigate vibrations generated by the seats of autonomous vehicles. Vibration measurements were acquired through experiments, and an analytical model was calibrated using beam elements to accommodate variations in constraints. To assess the efficacy of vibration reduction, a two-degree-of-freedom model was employed to characterize the dynamic damper. Sensitivity analysis of vibration magnitude indicated a significant reduction achievable with the dynamic damper. Configured as a 3D finite element model, the dynamic damper’s design factors were determined by mass and Young’s modulus. Results from the response surface methodology revealed an approximate 6 % margin of error in optimal parameters. Consequently, it was demonstrated that the vibration amplitude of the sheet could be reduced by approximately 50 %, and optimal parameters corresponding to this reduction were identified.