• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.94-102
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• 2022

Construction workers are engaged in many activities that may expose them to serious hazards, such as falling, unguarded machinery, or being struck by heavy construction equipment. Despite extensive research in building information modeling (BIM) for safety management, current approaches, detecting safety issues after design completion, may limit the opportunities to prevent predictable and potential accidents when decisions of building materials and systems are made. In this respect, this research proposes a proactive approach to detecting safety issues from the early design phase. This research aims to explore accident precursors and integrate them into BIM for tracking safety hazards during the design development process. Accident precursors can be identified from construction incident reports published by OSHA using a text mining technique. Through BIM-integrated accident precursors, construction safety hazards can be identified during the design phase. The results will contribute to supporting a successful transition from the design stage to the construction stage that considers a safe construction workplace. This will advance the body of knowledge about construction safety management by elucidating a hypothesis that safety hazards can be detected during the design phase involving decisions about materials, building elements, and equipment. In addition, the proactive approach will help the Architecture, Engineering and Construction (AEC) industry eliminate occupational safety hazards before near-miss situations appear on construction sites.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.223-224
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• 2023

Optimal fleet management in the planning stage is one of the most critical activities that guarantee successful construction projects. In South Korea, the construction standard production rate database (CSPRD) is normally employed. However, when it comes to a trade-off problem that involves decision-making on optimal sets of equipment to perform a certain task, the method will require the planners' in-depth knowledge and experience regarding the target process and a time consuming estimation of the performance of every possible scenario must be conducted for the deduction of the optimal fleet management. On this account, this research paper proposes a lightweight method of using mixed integer nonlinear programming (MINLP) in multi-objective problems based on CSPRD-based mathematical equations to assist planners in the preplanning stage of choosing the optimal sets of types and size machinery to efficiently arrange the construction scheduling and budgeting.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2006년도 추계학술대회 발표 논문집
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• pp.150-153
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• 2006

Micro vibration isolation, typically originated from ground, is always a prime concern for the nano-measurement instruments such as Atomic Force Microscopes. A four mount active vibration isolation system is proposed in this paper. Modeling and control of such a four mount system as analyzed. Combined active-passive isolation principle is used for vibration isolation by mounting the instrument on a passively damped isolation system made of Elastomer along with the active stage in parallel that consists of very soft actuation system, the Voice Coil Motor. The active stage works in combination with the passive stage for working as a very low frequency vibration attenuator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.258-261
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• 2006

The structure of small launch vehicle can be divided into engine section and payload section. This paper introduces modal test of the payload section of small launch vehicle which is composed to satellite, PLA (Payload Adapter), VEB (Vehicle Equipment Bay), KMS (Kick Motor Support) and KM (Kick Motor). From this test, dynamic properties of the 2nd stage structure of small launch vehicle can be obtained. In this test, to simulate free-free boundary condition, test object was hung by 4 bungee cords and excited by using impact hammer Modal test data are analyzed by using TDAS(Test Data Analysis Software). As the result, modal parameters and mode shapes below 100Hz of the 2nd stage of small launch vehicle were identified.

• 유공압시스템학회:학술대회논문집
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• 유공압시스템학회 2010년도 춘계학술대회
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• pp.18-24
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• 2010

Because of the increasing demand on the high precision and high response of a machinery, electronic control valves are widely adopted at various application fields. This paper studies on the static characteristic of a first-stage proportional pressure control valve. At first an experimental apparatus including hyd. pump variable speed inverter, pressure and data aquisition system was setted up with the experimental apparatus, various tests such as P-Q-W test, hyd, pump, dynamic, static, frequency response test of the proportional valve was carride out and the results are discussed.

• 한국분무공학회지
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• 제12권3호
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• pp.160-165
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• 2007

In this study, the breakup characteristics of mono disperse droplets were studied with various fuels, ethanol, diesel fuel, biodiesel fuel extracted from soybean oil, and pure water. In order to investigate the droplet behavior in air cross-flow conditions, the experimental equipment was composed of a droplet generator with an air nozzle, and a high-magnification photo detecting system. Droplets produced by the droplet generator were injected into the air stream flowing normal to a direction of liquid drop jet. Digital images of the droplet behavior in air flow field were recorded by controlling the air flow rate. From the inspections, droplet breakup mechanism is primarily classified into the two kinds of stage, first breakup stage and second breakup stage. At the first breakup stage, droplet deformation rate seems to be affected by the force induced by the surface tension and the viscosity. On the other hand, at the second breakup stage, droplet is broken up mainly induced by the surface tension, so the breakup transition can be divided by the regular Weber number.

• 한국정밀공학회지
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• 제31권5호
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• pp.423-430
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• 2014

In this study, the five-DOF motion at ultra-precision linear stage under static and dynamic conditions are evaluated through the extending application of ISO 230-2. As the performance factors, the bi-directional accuracy and repeatability of the five-DOF motion are quantitatively evaluated with the measurement uncertainties which are determined using the standard uncertainty of equipment used in experiment. The motion under static condition are analyzed using geometric errors. The five geometric errors except the linear displacement error are measured using optimal measurement system which is designed to enhance the standard uncertainty of geometric errors. In addition, the motion under dynamic conditions are analyzed with respect to the conditions with different feed rate of the stage. The experimental results shows that the feed rate of stage has a significant effect on straightness motions.

• 한국시스템다이내믹스연구
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• 제9권2호
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• pp.129-154
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• 2008

As a practical means to upgrade urban sustainability, this paper focuses on resource cyclical systems concerned with the waste of electric and electronic equipment (WEEE) in Korea. Borrowing System Dynamics concepts and approaches, it examines behavioral changes of WEEE dynamics to observe whether the existing management methods can be readjusted. The measurement is based upon both reuse and material and thermal recycle simulation works in the individual stage of WEEE discharge, collection, and treatment, going beyond the traditional recycle-only customs. This research estimates that the newly introduced Extended Producer Responsibility (EPR) system would definitely exert a significant impact on the final stage of WEEE treatment, decreasing the final treatment volume in the first half of the research period. The trend, nonetheless, would be reversed in the second half, mainly owing to the additional waste volume originated from the local government and recycling center. Sensitivity analysis poses, among others, that the local government-supported reuse center should take charge of a pivotal role in the long run. The research also shows that sufficientand necessary conditions for the WEEE management and treatment should be given to the combined efforts, both from the private sectors and the public domains. Based on these research findings, the paper recommends that key stakeholders including the producer and the public organizations should devise how to jointly carry out specific agenda centered around partnership or network buildings.

• 한국항공우주학회지
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• 제41권3호
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• pp.246-252
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• 2013

본 논문에서는 항공기에 장착되는 RF(Radio Frequency) 장비간의 신호 간섭을 방지하기 위한 방안으로 가해 장비의 RF 단에 필터를 사용하여 간섭 성분을 억제하는 방안을 제안한다. 특히 가해 장비에서 발생하는 고조파 성분의 억제를 위한 필터 설계와 필터 성능을 검증하기 위한 시험 방안을 제시한다. 필터는 U/VHF(Ultra/Very High Filter) 무전기와 데이터링크 시스템간의 간섭을 방지하기 위해 U/VHF 무전기의 RF 단에 설치하였다. 본 논문에서의 필터 설계와 시험 방안은 항공기에서 발생하는 간섭 문제에 대한 대책을 수립할 수 있는 도구로써 항공기 RF 장비 설계에 도움을 줄 것이다.

• 복식문화연구
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• 제18권6호
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• pp.1194-1210
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• 2010

The influence of digital media according to environmental change of multi-media came to have significance more than what we imagine. In accordance with high resolution of HDTV in digital media era, the cautious awareness is required for skin color by the immediate color such as replica of TV color, lighting and clothing. As for the broadcasting makeup expression technique caused by a change in broadcasting environment in the digital media era, the first, There is necessity for natural makeup technique, and for expressing the whole makeup evenly and very delicately. The makeup work gets much more delicate. For the delicate expression, more time is being required than the existing makeup time. Second, Lots of time and manpower are required for elaborate real-object processing on all the production fields such as background set, stage properties, and makeup. Third, Realistic expression is available on the screen. Importance of basic makeup is highlighted. Thus, even the skin care shop came to be prevalent. Development in only HD cosmetics is needed for foundation with fine particle in new material and with diverse colors hereafter. The video-media field is a method that is ignored a sense of distance through vehicles such as camera, picture tube, and several kinds of broadcasting machinery and equipment and that is delivered vividly to viewers through screen, unlike the stage makeup, thereby being needed the makeup technology proper for HDTV according to the changing broadcasting environment and media. The video machinery and equipment are proceeding with being gradually high-tech and precise. Thus, an expert in makeup needs to know common sense on the video machinery and equipment before makeup, and needs to make an effort according to it. And, a follow-up research can be said to be necessary on the advance in makeup method and on more diverse dedicated cosmetics along with a research on color tone proper for HDTV.