예산성결교회 / 예산성결교회당신축기

이창제 기독교대한성결교회 활천사 1934 활천 Vol.140 No.-

대형화면을 이용한 교육선진화

이창제 한국스쿨넷학회 2000 학술발표 논문집 Vol.2000 No.1

PIV를 이용한 수중로봇용 림 추진기 후류 특성에 관한 연구

이창제,허민아,조경래,김형호 한국수산해양기술학회 2022 수산해양기술연구 Vol.58 No.1

본 연구는 수중 로봇용 림 추진기의 기초연구이다. 림 추진기는 림의 회전운동 등으로 인해 프로펠러 추진 기와는 다른 유동특성을 가진다. 따라서, 림 추진기의 고유 유동 특성을 반영하여 설계할 필요가 있다. 본 연구 에서는 단면이 대칭인 NAC 0012를 기반으로 날개를 설계하였고, PIV를 이용하여 후류 특성을 파악하였다. 낮은 전진비에서는 model 2가 더 높은 속도를 보였으나, 높은 전진비에서는 model 1이 높은 속도를 보였다. 축방 향 속도는 model 1의 경우 전진비 전체에 걸쳐 대칭인 형태를 보였으나, model 2는 낮은 전진비(0.2, 0.4)에서 비대칭으로 나타났다. 이것은 자유 수면과 바닥의 영향이 후류 구조에 영향을 미치는 것으로 판단된다. 림 추진 기 내부에서는 덕트와 가까운 영역에서 와도가 높았으 나, 덕트의 영향으로 인해 후류 방향의 와도가 상당히 소멸되었다. 그러나 덕트 형상은 최적화 될 필요가 있다. 본 연구를 통해 소형 수중 로봇에 사용되는 림 추진기의 설계에 필요한 후류 특성의 정보를 제공하였다. 각 부하 조건에서 후류 특성을 통해 수중로봇이 효율적, 안정적 으로 구동될 수 있는 조건을 확인하였다. 향후 설계조건 과 운영조건을 다양화하여 연구를 진행하고자 한다.

API강재의 파이버레이저 용접시 유기되는 플라즈마의 방사특성 (II) -용접조건과 방사신호의 관련성-

이창제,김종도,김유찬,Lee, Chang-Je,Kim, Jong-Do,Kim, Yu-Chan 대한용접접합학회 2012 대한용접·접합학회지 Vol.30 No.4

Laser welding by fiber laser accompanied by a lot of spatter and humping bead. This is because the deep and narrow keyhole usually form due to high beam quality. So the weld bead is formed defects, because the plasma jet with a high vapor pressure make the molten pool on keyhole wall scattered. For such a reason, unstable behavior of keyhole is difficult to monitor laser welding by using the laser induced plasma. Mostly, fiber laser welding of thick plates most be influenced by this effect. Therefore, fiber laser welding has been difficult to apply the sole. Thus, laser welding monitoring based on plasma measurements have much difficulty in measurements and analysis of signal. In this study, influence of the plasma emission signal according to welding speed and laser power in fiber laser welding analysed by using RMS and FFT analysis. We can verify that RMS value of the plasma emission signal changes with welding parameters in fiber laser welding, and aspect ratio greater than 1, the peak of FFT frequency had been moved in accordance with welding parameter.

API강재의 파이버레이저 용접시 유기하는 플라즈마의 방사특성 (III) - 보호가스가 플라즈마 방사 신호에 미치는 영향 -

이창제,김종도,김유찬,Lee, Chang-Je,Kim, Jong-Do,Kim, Yu-Chan 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.3

Ar, $N_2$, and He are the conventional kind of shield gas that are used for laser welding. Many researches on the impact of laser welding shield gas have been done, and it is on going until now. However, there are few studies that analyze the changes and differences of the plasma emission signal. Therefore, in this study, we evaluated the change in the penetration characteristics according to the type of shield gas during fiber laser welding impacts to the plasma signal. As a result, if was checked that the difference in molecular weight of Ar, $N_2$, and He affects to the amount of spatter, and also found that the measured plasma radiation signal changes similar to the order of the molecular weight of the gases. Especially, clear change on the signal intensity per each shield gas was measured through RMS, and found that the shield gas was nothing to do with the FFT analyzed result.

디지털 제어를 이용한 알루미늄 아크 용접기의 기술현황

이창제,김유찬,김종도,Lee, Chang-Je,Kim, Yu-Chan,Kim, Jong-Do 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.1

Recently, welding technology of nonferrous metals which were difficult to implement by arc welder has become available through digitalization of arc welding machine. Among them, the welding quality improvement of aluminum welding is very noticeable. These results increase the arc stability by controlling arc current and voltage waveform precisely, and control wire feed speed by synchronizing with arc current which the feed rate of filler wire is controlled by a precise motor control of servomotor and not by a simple constant speed feeding. Not only through the hardware digitalization of arc welding machine but also through advance of software of arc welding, it became possible to implement a certain level of welding quality by a simple operation. These led to CMT welding process implementation which requires low heat input than current arc welding and highly increased the applicability of the aluminum welding.

파이버 레이저의 스테인리스강 용접시 인프로세스 모니터링을 위한 유기 플라즈마와 방사신호간의 상관성 연구(II) - 후판 용접시 측정신호의 특성 변화 -

이창제,김종도,Lee, Chang-Je,Kim, Jong-Do 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.6

On this study, we researched the in-process monitoring during fiber laser welding as well as on the first paper. On the previous/formal study, we analyzed the change of emission signal on thin plate welding. On this study, however, we analyzed RMS and FFT with emission signals in laser welding on lap joint and butt joint of 8mm-thick 316L stainless steel. As the result, the movement of specific frequency peak was observed according to welding speed changes. Furthermore, frequency peak as a result of FFT on the thick plate welding are much clearer than on the thin plate welding. Therefore, it is expected that the welding parameter changes can be predicted in case of applying FFT to in-process monitoring.

Study on Monitoring of Plasma Emission Signal in Lap Welding of Zn Coated Steel Sheet Using CO2 Laser

이창제,김종도,김유찬 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

In this study, induced plasma that is created during the CO2 laser lap welding of 6-mm-thick Zn coated steel for shipbuilding weremeasured through photo-diode and microphone. Then, we compared and analyzed the RMS value of plasma emission signal andspatter generation amount as a function of lap clearances with Zn coated thickness. The results indicated that as RMS valuesincreased depending on the amount of Zn vaporization, and RMS also changed abruptly when defects occurred depending on lap jointconditions. Also, as a result of obtaining FFT value of raw signal by welding conditions, the obtained frequency signal was about30 Hz at coating thickness 15 μm and about 50 Hz at coating thickness 30 μm in light signal, and in acoustic signal, peak valueappeared at about 1 kHz. In addition, it was found that when the frequency value was set as the bandwidth of bandpass-filter, andthe RMS values which were obtained after filtering raw signals were matched to weld bead. Thus we have considered that the signalsand defects were very closely related.

베이비부머의 노후를 대비한 사적 재무적 준비에 영향을 미치는 요인

박창제 ( Chang Je Park ) 한국사회보장학회 2011 사회보장연구 Vol.27 No.4

본 연구는 베이비부머의 사적인 재무적 노후준비에 대한 영향요인을 분석하고, 이를 바탕으로 정책적 함의를 논의하는 데 목적이 있다. 본 연구에서 사용된 자료는 노동연구원의 고령화연구패널 자료 중에서 1961년생에서 1955년생에 이르는 2,432명을 분석대상으로 삼았다. 본 연구의 개념체계는 Andersen 건강모형을 토대로 하였고 logistic 분석을 이용하여 영향요인을 찾고자 하였다. 분석결과는 다음과 같다. 첫째, 연금성 보험가입여부로 측정한 사적 재무적 노후준비 비율은 낮은 편이었다. 둘째, 소인적 특성요인 중에는 연령과 교육수준이 사적 재무적 준비에 영향을 미쳤지만, 성별과 결혼 상태는 유의한 영향을 주지 못하였다. 셋째, 가능자원요인 중에서 자녀수와 경제만족도를 제외한 경제활동, 가계소득, 주택보유, 고이자저축, 주식 및 투자신탁보유, 유산상속, 부채 등 많은 요인들이 사적 재무적 준비에 유의하게 영향을 미치는 것으로 나타났다. 넷째, 필요요인 중에서는 장애가 있음은 베이비부머의 사적 재무적 노후준비에 부정적 영향을 미친 반면, 장수가능성은 베이비부머의 사적 재무적 노후준비에 긍정적 영향을 미치는 것으로 나타났다. The purpose of this study is to analyse factors affecting private financial preparation for Aging of the Baby Boomers in Korea empirically, and then to discuss policy implications for the results of analysis. Data from Korean Longitudinal Study of Ageing(KLoSA) conducted by Korea Labor Institute are used in this study. From this dataset, 2,432 baby boomers born between 1961 and 1955 were selected for this study. The conceptual framework for this study was based on Andersen`s health behavioral model. The results is summarized as follows. First, baby boomers` private financial preparation proportion for aging measured by purchase of private pension insurances was low. Second, among predisposing characteristics, age and education had a statistically significant effects on private financial preparation for aging, but gender and married status did not have a statistically significant effects on private financial preparation for aging. Here is, age had negative effect, but positive effect on private financial preparation for aging. Third, among enabling resources, economic activities, household income, home ownership, high interest savings, having stocks and investment trusts, heritage gift possibility, having debts had a statistically significant effects on private financial preparation for aging of baby boomers. Here is, only having debts had negative effect on private financial preparation for aging. Fourth, among needs, having disabilities had a statistically significant negative effects but subjective expectation of potential longevity had a statistically significant positive effects on private financial preparation for aging of baby boomers.

가상영상 PIV기반 압력장 계산법 평가

이창제(Chang Je Lee),조경래(Gyong Rae Cho),김의간(Uei Kan Kim),김동혁(Dong Hyuk Kim),도덕희(Deog Hee Doh) 한국가시화정보학회 2016 한국가시화정보학회지 Vol.14 No.2

In this study, a Masked Omni-Directional Integration(MODI) method for pressure calculation is proposed using the Particle Image Velocimetry (PIV) data. To obtain the velocity field, the Affine PIV method was adopted. Synthetic images were generated for a solid body rotation. Calculation on the pressure was based on the Navier-Stokes equation. The results obtained by the MODI were compared with those obtained by theoretical pressure and by the Omni-Directional Integration(ODI) method. It was shown that the minimum error by the proposed MODI method was attained when the mask size was 1.