• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.28 no.6
• /
• pp.637-643
• /
• 2010

In this study, we developed a Portable Multi-sensor System, which consists of a video camera, a GPS/MEMS IMU and a UMPC to acquire video images and position/attitude data. We performed image georeferencing based on the bundle adjustment without ground control points using the acquired data and then evaluated the effectiveness of our system through the accuracy verification. The experimental results showed that the RMSE of relative coordinates on the ground point coordinates obtained from our system was several centimeters. Our system can be efficiently utilized to obtain the 3D model of object and their relative coordinates. In future, we plan to improve the accuracy of absolute coordinates through the rigorous calibration of the system and camera.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.211-211
• /
• 2003

PbTiO$_3$ 씨앗층을 이용하여 완화형 강유전체 Pb(Mg$_{1}$3/Ta$_{2}$3/)O$_3$ (PMT) 박막의 페로브스카이트 상안정화와 열처리 조건에 따른 미세구조변화, 이에 따른 전기적 특성 변화에 관하여 조사하였다. PbTiO$_3$ 박막을 스핀코팅법으로 3000 rpm에서 20초간(111) 방향으로 배향된 Pt / Ti / SiO$_2$/ Si 기판에 증착하여 안정화된 페로브스카이트 박막을 얻었다. 이렇게 제조된 PbTiO$_3$를 Buffer 층으로 사용하고 그 위에 Pb(Mg$_{1}$3/Ta$_{2}$3/)O$_3$를 박막을 Spin coating방법으로 증착한 후, 급속열처리 방법(RTA)으로 550- $650^{\circ}C$ 사이에서 열처리하였다. 제조된 박막의 열처리 온도에 따른 미세구조 변화와 결정성을 XRD, SEM, TEM으로 분석하였고 박막의 저온 강유전 특성을 RT66A를 이용하여 평가하였다. Pb(Mg$_{1}$3/Ta$_{2}$3/)O$_3$ 박막의 경우 씨앗층이 없는 경우에는 pyrochlore상이 주상이었지만 씨앗층을 사용한 경우 페로브스카이트 상이 주상임을 확인하였고 열처리 온도가 증가할수록 페로브스카이트상의 상대적 양이 증가함을 확인하였다. 미세구조와 상의 변화에 따른 전기적 특성 변화에 관하여 자세하게 논의할 것이다.

• Journal of Korean Institute of Industrial Engineers
• /
• v.31 no.4
• /
• pp.289-296
• /
• 2005

This study aims to measure maximum holding times(MHTs) of symmetric and asymmetric whole body postures, and to compare three representative observational methods including OWAS, RULA, REBA, based on the MHTs. An experiment was conducted for obtaining the MHTs, in which hand position was used as experimental variable, and the MHT and subjective discomfort rating as dependent variables. The hand position was defined by the percentage of the shoulder height(%SH), the percentage of the arm reach(%AR) and rotation angle(R). The results showed that three independent variables of %SH, %AR and R significantly affected on the MHTs at ${\alpha}$=0.01, and that the MHTs were negatively linearly related to the discomfort scores of Borg CR10. It was also revealed that OWAS and REBA were less sensitive to postural stress than RULA. In addition, OWAS and REBA underestimated postural load of given postures compared to RULA. Therefore, it is recommended that among the three observational methods investigated in this study, RULA be used for a more precise evaluation of postural load.

• Journal of Educational Research in Mathematics
• /
• v.15 no.2
• /
• pp.147-176
• /
• 2005

This study intends to examine the characteristics of mathematical literacy on Korean Students in PISA 2003(Programme for International Student Assessment 2003). We study the mean performance, the distribution of student performance, the student performance in terms of mathematics contents and process and situation and item format, the differences in mean scores between PISA 2000 and PISA 2003, and the gender differences in student performance. In addition to, we study students' engagement with mathematics, students' beliefs about themselves, students' anxiety in mathematics, and students' teaming strategies. Finally, we discuss the reasons of the characteristics of mathematical literacy on Korean students in PISA 2003, and suggest the implications for mathematics educators and educational policy-makers.

• The Optical Journal
• /
• s.143
• /
• pp.78-85
• /
• 2013

올해 중소기업 정책자금 지원규모는 3조 8500억 원으로 지난해 3조 3330억 원에서 15.5% 증가한다. 중소기업청과 중소기업진흥공단은 정책자금의 우선순위를 일자리 창출에 두고 민간금융기관을 통해 자금 조달이 어려운 창업자와 기술개발기업에 전체 정책자금의 40.3%인 1조 5500억 원을 배분한다. 이에 창업기업지원자금이 지난해보다 200억 원, 개발기술사업화자금이 420억 원 늘어나며, 정책자금을 지원받은 기업이 일자리를 1명씩 늘릴 때마다 0.1%포인트씩 최대 1%포인트까지 금리를 인하해 일자리 창출 효과를 극대화 한다는 계획이다. 또한 중진공을 통한 직접 대출 비중이 기존 55%에서 70%로 확대되며, 개발기술사업화자금, 수출금융, 소공인 특화자금은 전액 직접대출로 운영되고 운전자금에 대한 보증서부 대출은 폐지된다. 반면 신용대출 규모는 20% 늘어나 중소기업의 담보 부담이 줄어들 전망이다. 변화하는 산업 구조에 맞춰 정책자금 구조도 바뀐다. 담보력이 부족한 창업 및 소기업의 자금 지원을 위해 기계기구, 재고자산, 매출채권의 담보 인정비율을 높인다. 하반기 중에는 지식재산권 담보대출이 새로 도입된다. 별도의 기술가치 평가 모형을 통해 특허기술의 경제적 가치를 평가하고 특허권을 담보로 대출을 시행한다. 자세한 사항 및 정책자금 신청 희망기업은 중소기업진흥공단 홈페이지(www.sbc.or.kr) '정책자금 융자도우미'를 통해 신청요건 및 추천자금 등을 자가진단 후 신청하면 된다.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.10 no.4
• /
• pp.77-84
• /
• 2006

With the development of micro/nano spacecraft, concepts of micro propulsion are introduced for orbit transfer and drag compensation as well as attitude control. Micro solid propellant thruster has been attention as one of possible solution for micro thruster. In this paper, micro solid propellant thruster is introduced and research on basic components of a micro solid propellant thruster is reported. Micro Pt igniter was fabricated through negative patterning and quantitative effect of geometry was estimated. The characteristic of HTPB/AP solid propellant was investigated to measure the homing velocity. A combustion chamber was fabricated by means of anisotropic etching of photosensitive glass. Finally, micro solid propellant thrusters having various geometries were fabricated and tested.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.139-142
• /
• 2011

A water-flow test for acceptance verification is carried out for a nonimpinging-type injector prior to the design-performance verification of hydrazine thruster under development. The injector used in the experiment is to be equipped on the hydrazine thruster producing 70 N of nominal thrust at an inlet pressure of 24.6 $kg_f/cm^2$. It is observed that there exist varying characteristics of atomization among the injector-nozzle orifices caused by a fabrication error which can be judged from a microscopic standpoint. On the other hand, all of the injector orifices are placed within the design criteria in an injection-angle performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.05a
• /
• pp.425-431
• /
• 1999

We develope plasma monitoring system which detect plasma signals and store them for Laser welding quality evaluation and analysis using photo detector. The most fundamental and important aspects in such a system are signal restoration fidelity, noise immunity and noise cancelation capability. In this paper, we propose implementation method using distribute processing structure and hybrid digital communication for high noise cancelation capability, immunity and signal fidelity which are poorly presented in other researches. Lab experimental results and welding experimental results show a effectiveness of proposed method and plasma data is stored with 256 kbps without any communication error. we are implementing various welding defect recognition algorithm in this system.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.8
• /
• pp.877-882
• /
• 2011

Stabilizers are balancing equipment that can reduce the severe rolling of ships, vehicles, and aircraft. We manufactured a stabilizer link using a metal and a composite material with 25% POM-GF. We evaluated the strength of the stabilizer link via tensile, compressive, and ball-stud separation. The standard criteria were satisfied. Of four types of rod, knurled rod has the greatest strength. We improved the shape of the stabilizer-link body by a reanalysis of the injection molding.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.3
• /
• pp.50-57
• /
• 2003

In the paper, the design and evaluation of a helicopter trajectory tracking controller are presented. The control algorithm is implemented using the feedback linearization technique and the two time-scale separation architecture. In addition, and on-line adaptive architecture that employs a neural network compensating the model inversion error caused by the deficiency of full knowledge of helicopter dynamic is applied to augment the attitude control system. Trajectory tracking performance of the control system in evaluated using modified TMAN simulation program representing as Apache helicopter. It is show that the on-line neural network in an adaptive control architecture is very effective in dealing with the performance depreciation problem of the trajectory tracking control caused by insufficient information of dynamics.