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        검색결과 25

        1.
        2024.04 구독 인증기관·개인회원 무료
        노후 구조물의 동적 특성 평가를 위해 대표적인 접촉식 센서인 LVDT와 가속도계를 활용한다. 전통 적인 센서의 데이터 신뢰성은 높지만, 작동 원리로 인하여 대상 구조물의 물리적 접근과 센서의 설치 가 필요하다. 조밀한 센서 설치를 위해선 많은 수의 센서와 데이터 수집장치도 추가적으로 필요하다. 이런 단점을 보완하고자 비접촉식 센서의 개발이 활발히 진행 중이며, 특히 비전센서를 활용한 동적 변위 측정에 관한 연구 및 개발에 많은 진척이 있다. 비전센서를 활용한 동적 변위 측정 시스템은 내 적 파라미터 및 외적 환경조건에 따라 측정 정확도가 크게 변화한다. 주된 내적 파라미터로 영상장비 의 공간분해능은 이미지 센서의 물리적 크리와 촬영거리의 증가 혹은 관심영역이 작아짐에 따라 영향 을 많이 받는다. 외적 환경조건으로 저조도 환경에서 타겟의 밝기차이가 줄어들어 이미지 프로세싱 과 정에서 불리한 조건이며, 이는 동적 변위 측정 정확도 저하로 이어진다. 본 연구에서 저조도 환경에서 비전센서의 운용거리 한계를 초해상화를 적용하여 극복하고자 하며, 인공적 및 자연적 타겟에 대한 동 적 변위 측정 성능을 비교 분석하였다. 동적 변위 측정 실내 실험을 위해 저조도 조건에서 3층 전단 구조물을 9Hz로 가진하였다. 동시에 Sony사의 DSC-100M7 카메라를 활용하여 조화진동으로 인해 발생되는 각층의 변위를 FHD화질 120FPS로 촬영하였고 측정 정확도 비교 분석을 각층의 LVDT 측 정값으로 진행하였다. 촬영거리를 10m를 기준으로 10m씩 증가하면서 최대 40m까지 변위 값을 측정 하였으며, 공간분해능 증가를 위해 GAN기반 초해상화 모델인 RealSR을 적용시켰다. 초해상화를 활용 하여 동적변위를 측정한 결과 저조도 환경에서도 비전센서의 운용 거리가 증가함을 확인할 수 있었으 며, 동시에 변위 측정 정확도도 함께 상승하는 것을 보여줬다.
        4.
        2022.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to determine the changes in ginsenosides content according to additional UV-A, and UV-B LED irradiation before harvesting the ginseng sprouts. One-year-old ginseng seedlings (n=100) were transplanted in a tray containing a ginseng medium. The ginseng sprouts were grown for 37 days at a temperature of 20°C (24h), a humidity of 70%, and an average light intensity of 80 μmol·m-2·s-1 (photoperiod; 24h) in a container-type plant factory. Ginseng sprouts were then transferred to a custom chamber equipped with UV-A (370 nm; 12.90 W·m-2) and UV-B (300 nm; 0.31 W·m-2) LEDs and treated for 3 days. Growth parameters and ginsenoside contents in shoot and root were conducted by harvesting on days 0 (control), 1, 2, and 3 of UV treatments, respectively. The growth parameters showed non-significant differences between the control and the UV treatments (wavelengths or the number of days). Ginsenoside contents of the shoot was highly improved by 186% in UV-A treatment compared to the control in 3 days of the treatment time. The ginsenoside contents of the roots was more improved in UV-A 1-day treatment and UV-B 3-day treatment, compared to the control by 171% and 160%, respectively. As a result of this experiment, it is thought that UV LED irradiation before harvesting can produce sprout ginseng with high ginsenoside contents in a plant factory.
        4,000원
        5.
        2018.10 서비스 종료(열람 제한)
        The purpose of this experimental study is to develop an waterborne silicon acrylic top finishing material of car parks. The gas toxicity test was conducted in order to provide fundamental data for developing the material by implementing modified polyamide resin. The outcomes were satisfied by the quality standard regarding elapsed mean stop times of mice which is prescribed in KS F 2271. As conclusion, this study confirmed that the developed finishing material could be an optimum material capable of applying for car parks’ deck.
        6.
        2018.10 서비스 종료(열람 제한)
        The purpose of this experimental study is to develop an water soluble silicone acrylic surface finishing material of car parks. The heavy metal contents test was conducted in order to supply a guideline for developing a top finishing material. As a results, the sample was satisfied with the quality standard regarding heavy metal contents which is prescribed in KS F 3888-2 of En 71-3. As conclusion, this study confirmed that the developed top finishing material could be an optimized material usable for car parks’ deck.
        7.
        2018.04 서비스 종료(열람 제한)
        The purpose of this experimental study is to develop the waterborne silicon acrylic surface finishing material of parking lots. Pollutant emission test was conducted in order to give a guide datum for developing the material by implementing modified polyamide resin. As a result, specimens satisfied with the quality standard regarding TVOc, HCHO, Toluene which is prescribed in KS F4937. As conclusion, this study confirmed that the developed finishing material could be an optimized surface finishing material usable for parking lot floor.
        8.
        2018.04 서비스 종료(열람 제한)
        The purpose of this experimental study is to develop the waterborne silicon acrylic finishing material of parking lots. Resistance-Wheel moving load test was conducted in order to supply basic datum for developing the material by implementing modified polyamide resin. As a result, all the specimens were satisfied by the quality standard regarding dynamic wheel load resistance which is prescribed in KS F 4937. As conclusion, this study confirmed that developed finishing material could be an optimum surface finishing material capable of applying for parking lots’ floors.
        9.
        2018.04 서비스 종료(열람 제한)
        The purpose of this experimental study is to develop the waterborne silicon acrylic surface finishing material of parking lots. Adhesion strength experiment was conducted in order to enhance performance of the finishing material by adopting modified polyamide resin. The results qualified the standard regarding bond strength which is prescribed in KS F 4937. They are confirmed that the strength tend to increase as the amount of polyamide increased and could be an optimum surface finishing material applicable for parking lot floor.
        10.
        2017.09 서비스 종료(열람 제한)
        The purpose of this experimental study is to carry out test for the surface finishing material of parking lot using Cross-linking agent(Zinc Oxide). The specimen was fabricated by KS F 4937, Cross-linking agent 2%, 3%, 4% is mixed in water soluble acrylic resin. As a result, bond strength of surface finishing material using Zinc oxide 4% was confirmed to be superior than surface finishing material using ordinary Acrylic resin.
        11.
        2016.10 서비스 종료(열람 제한)
        The existing domestic bridge has become deterioration with the increase of bridges to be managed. Therefore appropriate maintenance such as an inspection, diagnosis, repair, and rehabilitation is required to extend the service life of the bridge. The domestic and international cases of the maintenance budget for bridges were investigated and analyzed. As a result, surveyed countries represent maintenance cost as only accounting values without clear and accurate categorized maintenance items.
        12.
        2016.04 서비스 종료(열람 제한)
        A lot of bridges have been built with economic growth and national development for a long time. The existing domestic bridge has been become deterioration with the increase of the quantity management. Therefore appropriate maintenance such as an inspection, diagnosis, repair, and rehabilitation is required to extend the service life of the bridge. The domestic and international cases of the maintenance for inspection personnel were investigated and analyzed. As a result, there was hardly clear and accurate criteria about inspection personnel but Denmark. However, the qualification and competence of the team members have been presented.
        13.
        2015.10 서비스 종료(열람 제한)
        Recently efficient maintenance technology has been rising because of the structural deterioration. Specific technology development and research related to the real-time monitoring has been conducted in various ways. All-in-one enclosure including GPS was fabricated to measure the displacement of the retaining wall structure exposed the extreme environment such as very high and low temperature. Also it measured the displacement of the structure under the phased construction.
        14.
        2015.04 서비스 종료(열람 제한)
        Presently, the wind power tower grows actively in all countries of the world as the part of renewable energy securing. Recently, as to the wind power tower, the advance to and diversification of the wind power tower form and material are made. but the maintenance manual about the wind power tower in which this foundation is based is insufficient. therefore, the object is that in being safe and maintaining efficiently the wind power tower, by developing the maintenance manual about the fundamental vulnerable element the life span improvement of the wind power tower is planned and it contributes to the maintenance management technology development.
        15.
        2014.10 서비스 종료(열람 제한)
        The maintenance of the general structures has been studied until today. but maintenance guide line of the wind power tower has not been studied yet. In this study it was performed analysis on structural features through wind power tower technique data survey. which can be developed to basic data for the wind power tower maintenance manual through analysis of vulnerable elements.
        16.
        2014.04 서비스 종료(열람 제한)
        This study was conducted to investigate the Structural Health Monitoring(SHM) system built in large-scale structures. Recently large-scale structures such as bridges and high-rise building have installed SHM system and using the SHM system, large-scale structures are monitoring the status of structures. In many practical cases, SHM systems are used sensor, such as strain gauge, inclinometer, accelerometers, seismic, wind anemometer, GPS, to monitor status of structures. This case study foreground potential future research dealing with SHM system using integrated sensor module.
        18.
        2012.11 서비스 종료(열람 제한)
        During modular bridge construction, the construction delay and the problems of workability due to the high-altitude operations are occurred by using in-site concrete diaphragm. To solve these problems, selected alternative suitable for modular bridge diaphragm is needed. Therefore, in this study, to select the suitable diaphragm for modular PSC T-Girder bridge, seven diaphragm specimens were fabricated and static loading tests were carried out. Through the static load tests, the behavior of diaphragm in terms of joints and load distribution was observed and experimental results were analyzed and compared with each data. Finally, the alternative of suitable diaphragm for modular PSC T-Girder bridge was proposed considering the structural performance and workability.
        19.
        2012.11 서비스 종료(열람 제한)
        This research was performed to evaluate physical properties of polysulfide epoxy overlay material for bridge deck, as part of a review for possibility of domestic of epoxy polymer concrete binder for thin bridge deck pavements. After mix test, carry out experiment such as harden, viscosity, tensile, compressive strength and Ultraviolet ray test for evaluate strength and durability characteristics. The tests showed that the results, met the criteria suggested by the ACI in hardness, viscosity, tensile strength and compressive strength. Furthemore, a comparsion of the in this study and goods of Transpo.co in USA, this study were excellent.
        20.
        2012.05 KCI 등재 서비스 종료(열람 제한)
        본 연구는 RTK-GPS (Real Time Kinematic-Global Positioning System) 측위법을 이용한 변위 계측 결과, 가속도계를 이용한 변위계측 결과, 그리고 LVDT(Linear variable differential transformer)의 변위계측 결과를 비교하여 RTK-GPS와 가속도계 센서를 구조물에 적용할 때의 문제점들을 파악하였다. 또한, 관측빈도와 측위 정확도를 향상시킨 RTK-GPS와 가속도계를 이용한 변위계측 결과를 통합 계산하여 절대변위인 LVDT와 비교를 통해 생성된 통합 변위의 정확도와 타당성을 확인하였다.
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