• 한국CDE학회논문집
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• 제20권2호
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• pp.171-181
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• 2015

Building Information Modeling (BIM) provides many advantages when it is adopted in virtual design construction, to analyze constructability, etc. For this reason, advanced countries have made it mandatory to adopt BIM in public construction projects. The Korea Public Procurement Service announced that from 2016, BIM adoption will be mandatory in every construction project in Korea. Currently, however, it is not possible to fully adopt BIM in the building design process domestically because BIM-based systems have not been used broadly in Korea's building approval system (Seumter). In this research, four challenges were drawn from a focus group interview. Focusing on tackling one challenge, this paper reviewed previous research into building approval systems and the building approval systems of Singapore, the U.K. and the U.S., and identified elements of the building approval application process and presents a system to create and manage the information. The system supports the creation and management of information and 2D drawings from an IFC-based BIM model. We expect that the system will encourage designers to use BIM from the beginning of the design process and ultimately increase the efficiency of design in a BIM-based project.

• 제어로봇시스템학회논문지
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• 제14권10호
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• pp.1038-1046
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• 2008

This paper presents a framework to generate human-like movements of a humanoid in real time using the movement primitive database of a human. The framework consists of two processes: 1) the offline motion imitation learning based on an Evolutionary Algorithm and 2) the online motion generation of a humanoid using the database updated bγ the motion imitation teaming. For the offline process, the initial database contains the kinetic characteristics of a human, since it is full of human's captured motions. The database then develops through the proposed framework of motion teaming based on an Evolutionary Algorithm, having the kinetic characteristics of a humanoid in aspect of minimal torque or joint jerk. The humanoid generates human-like movements far a given purpose in real time by linearly interpolating the primitive motions in the developed database. The movement of catching a ball was examined in simulation.

• 천문학회보
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• 제38권2호
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• pp.100.1-100.1
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• 2013

다가오는 거대마젤란망원경 (GMT) 시대를 이끌어갈 신진 연구자들의 연구역량 증진을 위해, 2013년 8월 27일부터 30일까지 3박4일에 걸쳐 강원도 홍천 가람밸리 리조트에서 제3회 거대마젤란망원경 여름학교를 개최한다. 총 47명의 대학원생과 박사후연구원들이 참여하는 이번 여름학교에서는, GMT 개관, 1세대 관측기기 가운데 최초로 활용될 계획인 GMACS와 G-CLEF의 소개 및 그것들을 활용한 대표적인 과학연구 분야에 대한 강의가 이루어진다. 또한 계절학교 참가자들이 'GMACS 또는 G-CLEF를 활용한 관측연구 제안'이라는 주제로 직접 토론과 발표에 참가하는 조별 활동이 주된 프로그램으로 추가된다. 이러한 여름학교 프로그램은 신진 연구자들이 GMT를 활용한 다양한 연구 가능성을 경험하고 서로 능동적으로 교류할 수 있는 계기가 될 것으로 기대된다. 2013년도부터 새로운 방식으로 시도되는 제3회 거대마젤란망원경 계절학교 결과를 정리함으로써 앞으로 나아갈 계절학교의 방향을 점검해본다.

• 한국생산제조학회지
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• 제21권4호
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• pp.644-650
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• 2012

This paper show the 2kW fiber laser cutting properties of SS400. The study was comparison of traditional 4kW $CO_2$ Laser cutting and 2kW Fiber laser cutting characteristics for the application of Industrial 2D Laser Cutting Machine. The laser used in this investigation was an IPG YLU-2000 multi-mode Ytterbium Fiber machine with a maximum power of 2000W and a wave length of 1070 nm. The laser was used in its Continuous Wave (CW) mode with an approximately top hat beam intensity distribution. Fiber laser high quality cuts at a large range of speeds (ranging from 2000 to 3800 mm/min) which has been obtained for the 2.3mm Sheet of SS400. 2kW power Fiber laser cut was able to max. 20mm sheets of SS400 (speed range from 650 to 850 mm/min). Fiber laser cutting used in conventional hole nozzle could cut 12mm SS400 but used in special dual cutting nozzle could cut 20mm SS400.

• 한국생산제조학회지
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• 제22권4호
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• pp.643-651
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• 2013

This study applied a laser cleaning method (dry cleaning) that is used for cleaning semiconductor elements to dental implant cleaning. The lasers used in this study were pulsed fiber lasers with wavelengths of 1,064 and 532 nm. The peak output, energy per pulse, energy density per pulse, time of pulse experiment, and number of pulse experiments served as process variables for this study, and the variables were changed for each experiment. As a result, a laser with a wavelength of 532 nm showed much higher cleaning efficiency than its 1,064 nm counterpart. As the wavelength range decreased, the quantized energy increased and the reflection rate of the titanium used for the implant decreased; consequently, the energy absorption rate increased. Therefore, it is proposed that the energy density by wavelength has a greater influence on cleaning than does the output size.

• 한국레이저가공학회지
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• 제17권3호
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• pp.1-9
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• 2014

In this study, we analyzed fiber laser welding for the pure copper thin plates in a series of secondary lithium-ion batteries; and performed the experiment for the purpose of the preceding study to replace bolt joints method the with the laser welding method. We have changed the peak power of the laser from 5 to 6kW, the pulse duration by 4, 6, 8, and 10ms, the frequency by 10, 12, 16, and 25Hz, and the focal position by -3, 0, and +3. As a result, when the focal position is at +3, the peak power is 5kW, and the pulse duration and the Frequency are 4ms and 25Hz, respectively, we obtain 2.1 and 2.5 times better tensional strengths, respectively, than the highest values of tensional strengths obtained with the focal positions at 0 and -3.

• 한국레이저가공학회지
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• 제16권3호
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• pp.11-21
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• 2013

As parts are becoming more complex and smaller with the development of new materials, high-quality laser precision processing is getting the limelight. Laser enables quick processing and less deformation of materials. It also enables welding with diverse materials. In this study, the pole rod and tap for the secondary battery were laser-welded using cross and coaxial nozzles. The results of the comparative analysis of cross and coaxial nozzles according to the processing parameters showed that the coaxial nozzle had more sensitive welding characteristic to the nozzle position or pressure than the cross nozzle. This indicated that the processing parameters should be carefully determined for the welding with the coaxial nozzle. The pole rod and tap were welded together in a form of T joint to improve the output of the secondary battery, and the cross nozzle had a better welding characteristic than the coaxial nozzle.

• 한국정밀공학회지
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• 제30권5호
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• pp.499-506
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• 2013

Heat-treatment is one of the core technologies to enhance various characteristics such as strength, hardness, toughness, abrasion resistance and fatigue resistance for the mold material. This paper focuses on characteristics of the laser heat-treatment according to the cylindrical bar diameter variation in case of the SM45C. From the results of the experiments, it has been observed that the maximum hardness is 744Hv when the power is 1630W and the travel of laser is 0.5m/min. And then, the hardness width, depth and microstructure were observed for characteristics. Finally, when the cylindrical bar diameter size grow, the hardness width decrease whereas hardness depth increase.

• 한국해양공학회지
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• 제23권6호
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• pp.12-16
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• 2009

In this study, the wave profiles and kinematics of highly nonlinear waves at various water depths were calculated using a 2D fully nonlinear Numerical Wave Tank (NWT). The NWT was developed based on the Boundary Element Method (BEM) with the potential theory and the mixed Eulerian-Lagrangian (MEL) time marching scheme by 4th-order Runge-Kutta time integration. The spatial variation of intermediate-depth waves along the direction of wave propagation was caused by the unintended generation of 2nd-order free waves, which were originally investigated both theoretically and experimentally by Goda (1998). These free waves were induced by the mismatch between the linear motion of wave maker and nonlinear displacement of water particles adjacent to the maker. When the 2nd-order wave maker motion was applied, the spatial modulation of the waves caused by the free waves was not observed. The respective magnitudes of the nonlinear wave components for various water depths were compared. It was found that the high-order wave components greatly increase as the water depth decreases. The wave kinematics at various locations were calculated and compared with the linear and the Stokes 2nd-order theories.

• 한국정밀공학회지
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• 제29권4호
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• pp.395-408
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• 2012

An experimental investigation with 2.8kW Nd:YAG laser system was carried out to study the effects of different laser process parameters on the microstructure and hardness of STD11. The optical lens with the elliptical profile are designed to obtain a wide surface hardening area with uniform hardness. The Laser beam is allowed to scan on the surface of the work piece varying the power (1600, 1800 and 1900kW) and traverse speed (200, 400, 600, 800 and 1000mm/min) at three different F-numbers of lens. After laser surface treatment three zones, In the microstructure have been observed : melted zone(decarburization), heat affected zone(martensite), and the substrate.