협력 트랜잭션의 관리

이재혁(Jai-Hyuk Lee),이윤준(Yoon-Joon Lee) 한국정보과학회 1994 한국정보과학회 학술발표논문집 Vol.21 No.1

데이타베이스 응용분야에서 트랜잭션 관리에 대하여 많은 연구가 있었고, 그 연구 결과는 실제로 응용되고 있다. 그러나 CAD/CAM, 하이퍼미디어, 소프트웨어 공학 등 새로운 응용분야에서는 종래의 트랜잭션 관리 기법을 그대로 적용할 수가 없다. 이같은 응용분야의 트랜잭션이 갖는 특성을 협력(coopperative), 대화(interactive)와 장기(long)임으로 구분하고, 종래의 고립성(isolation)과 새로운 응용의 협력성(cooperation)의 상반된 개념이 종래의 트랜잭션 관리 기법을 적용할 수 없는 이유임을 보였다. 따라서 새로운 응용에서는 고립성 뿐만 아니라 협력성도 함께 지원할 수 있는 방법이 필요하다. 이 협력성을 위해 4가지 협력형태(coopperation form)를 제안하고, 이를 위한 트랜잭션 관리 시나리오를 제안하였다.

햅틱 진동자 시스템 성능인자 예측 및 Monte Carlo Simulation을 통한 진동 성능 예측 방법에 대한 연구

이재혁(Jai Hyuk Lee),허덕재(Deog Jae Hur),고동신(Dong Shin Ko),이성수(Sung Su Lee) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11

This study describes the characteristics on the electromagnetic force and the frequency bandwidth of the design parameters for upgrading the vibrator. Performance improvement is to maximize the band width at a constant acceleration. Design parameters were selected for the relevant position, height and width of the permanent magnet affecting to the excitation forces and were selected the spring stiffness and magnet weight affecting to the frequency response function. To consider the effect on electromagnetic force and band width improvement, this study was analyzed by both an independently variable and the coupled multi variables in these factors. Multi-factor analysis of the variables was applied to the full factorial experimental design, predictive model was induce the second order regression equation which include the nonlinearity of utilizes response surface methodology. In addition, performance prediction of electromagnetic force and band width for probability distribution of the physical design parameters was analyzed using Monte Carlo simulation applied to the regression model. A significance of the independence and interaction of the factors was analyzed by F-test, and it appeared to be the effective six variables which are three independence variables and three interaction effect variables. It was able to the design target value in the analysis of confidence interval over 99.7%, and the probability distribution of electromagnetic force was obtained in a mean value of 0.0399N and standard deviation 0.006N which is increased 73.5% from the design target value, the probability distribution of band width was obtained in a mean value of 27.86㎐ and standard deviation 4.54㎐ which is increased 85.7% from the design target value. It is determined to be able to make verification the design variable on performance and a reliable verification on prediction result by statistical analysis.

2차원 제스춰 인터페이스를 사용하는 한글 문서편집기의 설계와 구현

이재혁(Jai Hyuk Lee),김진형(Jin Hyung Kim),이윤준(Yoon Joon Lee),김명호(Myoung Ho Kim) 한국정보과학회 1992 한국정보과학회 학술발표논문집 Vol.19 No.2

제스춰란 “의미를 담고있는 몸짓”이라고 정의 할수있으며 기존의 키보드나 마우스등의 입력 장치와 같은 기계본위의 동작과는 다르게 실생활에서 쓰는 몸의 동작을 그대로 기계가 인지하는 인간 본위로의 전환이라는 점에서 중요한 의미를 갖는다. 최근에는 키보드나 마우스없이 펜만으로 입력을 하는 펜 컴퓨터가 상품화가 되고있는데 이 논문에서는 기존의 펜 컴퓨터에서의 제스춰를 확장하고 이것을 응용하여 2차원 제스춰 인터페이스를 사용하는 한글문서 편집기를 설계와 구현한다.

골전도 스피커의 성능향상을 위한 전자기력 예측과 Monte Carlo Simulation에 의한 성능 분포에 대한 고찰

이재혁(Jai Hyuk Lee),허덕재(Deog Jae Hur),고동신(Dong Shin Ko),김재용(Jae Yong Kim) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.10

This study is about the probabilistic characteristics of electromagnetic force of bone conduction speaker, which is applied to the smart glass, a smart wearable device. There is a variety of design parameters related to improve the bone conduction speaker performance. In this paper, the factors which improve the electromagnetic force were selected plate thickness, magnet height and coil turn. To consider the effect of these factors on electromagnetic force improvement, this paper has studied both an independent analysis by a single variable and characteristics of the multi variable. Factors for multiple variables were analyzed by applying a full factorial design of experiment. In addition, the Monte Carlo Simulation was used for the prediction of the electromagnetic force for distribution of the physical design parameters, and the prediction equation was used by creating a nonlinear regression. A significance analysis of the independence and interaction factors was conducted in F-test, and it was found three independent variables and one interaction effect to be valid. It was able to satisfy the design target value in the analysis of the reliability over 99%, and the distribution was obtained in a standard deviation of 0.003 and a mean value of 0.057, which is increased 18.8% from the design target value. It is suggested to be able to verify the impact on performance if utilizing this statistical analysis method in design step, and to be able to make a reliable verification of the prediction result accordingly.

광PCB를 위한 폴리머 저온 접합기술 연구

차두열,이재혁,장성필,Cha, Doo-Yeol,Lee, Jai-Hyuk,Chang, Sung-Pil 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.1

As the demands for the higher data transmission speed and capacity as well as integration density grow throughout the network, much works have being done in order to integrate the Electrical PCB with Optical PCB. However, one of the most troublesome problems in the commercial bonding process is to need the high temperature for the bonding. Due to the high temperature bonding process, lots of side problems are followed such as warpage and crack, etc. In this paper, we tried to develop the new bonding technology with low temperature around $100^{\circ}C$. As a result of this study, the PCB bonding technology with high bonding strength is demonstrated with the value of bonding strength from 7 to 8 MPa at the temperature of $100^{\circ}C$.

마이크로 머시닝 기술을 이용한 니켈기반의 압전 진동형 에너지 하베스터 제작

차두열,이재혁,장성필,Cha, Doo-Yeol,Lee, Jai-Hyuk,Chang, Sung-Pil 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.1

Owing to the rapid growth of mobile and electronic equipment miniaturization technology, the supply of micro mobile computing machine has been fast raised. Accordingly they have performed many researches on energy harvesting technology to provide promising power supply equipment to substitute existing batteries. In this paper, in order to have low resonance frequency for piezoelectric energy harvester, we have tried to make it larger than before by adopting nickel that has much higher density than silicon. We have applied it for our energy harvesting actuator instead of the existing silicon based actuator. Through such new concept and approach, we have designed energy harvesting device and made it personally by making with micromachining process. The energy harvester structure has a cantilever type and has a dimension of $10{\times}2.5{\times}0.1\;mm^3$ for length, width and thickness respectively. Its electrode type is formed by using Au/Ti of interdigitate d33 mode. The pattern size and gap size is 50 ${\mu}m$. Based on the measurement of the nickel-based piezoelectric energy harvester, it is found to have 778 Hz for a resonant frequency with no proof mass. In that resonance frequency we could get a maximum output power of 76 ${\mu}W$ at 4.8 $M{\Omega}$ being applied with 1 g acceleration.

투자율이 높은 NiFe 코어를 이용한 마이크로 트랜스포머 제작

조세준,차두열,이재혁,이수진,장성필,Cho, Se-Jun,Cha, Doo-Yeol,Lee, Jai-Hyuk,Lee, Soo-Jin,Chang, Sung-Pil 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.3

Recently as the electronic devices are getting to be more and more smaller, transformers are needed to be micro fabricated using MEMS technology. In this paper transformers have been fabricated and measured by depositing insulation layer to reduce the loss of eddy current and in the middle core a high permeability permalloy was designed based on the turns ratio between primary coil and secondary coil which are 1:1 transformers. (the number of turns of primary coil and secondary coil: 3/3, 5/5, 7/7). The size of the transformers including ground shield are $1mm{\times}1.5mm$, $1mm{\times}1.95mm$, $1mm{\times}2.35mm$ respectively. The line width, pitch and the height of post are 50um. Based on the measured data from the micro fabricated transformers, the 3/3 turns in the primary coil and secondary coil showed the lowest insertion loss with 1.5 dB at 480 MHz and the 7/7 turns in the primary coil and secondary coil showed the highest insertion loss with 2.5 dB at 280 MHz. Also confirmed that the bandwidth goes up as the number of turns goes down. There was some difference between the actual measured data and the HFSS simulation result. It looks as if it is an error of the difference between oxidation of copper or the permeability of SU-8.

하이퍼텍스트 방식을 이용한 관계형 데이타베이스 검색 기법에 관한 연구

정병희(Byung Hee Jung),이재혁(Jai Hyuk Lee),홍석희(Seok Hee Hong),이윤준(Yoon Joon Lee) 한국정보과학회 1995 한국정보과학회 학술발표논문집 Vol.22 No.2A

현재 하이퍼 미디어 시스템은 다양한 미디어로 구성된 자료들을 노드, 링크의 집합으로 구성하고 조작하는 방법과 이로인한 장점으로 인해서 정보 검색 시스템으로서 보편화되고 있으며 이 분야의 연구가 활발히 진행되고 있다. 하이퍼 미디어 시스템을 통해 더 많은 정보를 효과적으로 제공하기 위해서는 기존의 데이타베이스를 통해 축적된 정도도 하이퍼 미디어 시스템을 통하여 같이 제공하여야 하며, 이에 대한 기존의 연구는 제한된 정보를 정보제공자의 조작을 통해 제공하였다는 점에서 문제가 있다. 본 논문에서는 하이퍼 텍스트 방식으로 기존의 구축되어 있는 관계형 데이타베이스를 검색하는 기법을 제안한다. 이러한 기법은 데이타베이스 설계시에 형성되는 스키마로 부터 노드와 링크 생성의 기초 정보를 얻는다. 본 논문에서 제안한 기법을 기반으로 하여 데이타베이스 내의 자료들을 검색하게 되면 질의어의 사용법을 모르는 검색자도 하이퍼 미디어 시스템을 사용하는 것과 동일한 방법으로 검색을 수행하여 단순 질의를 사용해서 데이타베이스를 검색한 것과 동일한 결과를 얻을 수 있다.

수평 착자형 액추에이터의 전자기력 성능 향상에 관한 연구

허덕재(Deog Jae Hur),이재혁(Jai Hyuk Lee),권상엽(Sang Youp Kwon),이성수(Sung Su Lee) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.4

This paper describes optimization design to improve the performance of bandwidth and the maximum acceleration of the linear AC vibrator with horizontal magnetization. The variable was set the electromagnetic force of the exciting force of the haptic vibrator. Optimization in horizontal magnetization design leads the maximum electromagnetic force when the permanent magnet and coil are centrally aligned. In addition, when increasing the width and height of magnet, the electromagnetic force has increased also. The final optimized design is applied with the parameter combination, and the electromagnetic force has risen about 81.4% compared to the previous model.

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.