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        검색결과 113

        41.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The demand for skyscrapers is increasing worldwide. Until now, various lateral resistance structures have been used for lateral displacement control of high-rise buildings. An outrigger damper system has been introduced recently to improve lateral dynamic response control performance further. However, a study of outrigger damper system is yet to be sufficiently investigated. In this study, time history analysis was performed to investigate the control performance of an outrigger damper system of high-rise building under eccentric loading. To do this, an actual scale 3-dimensional tall building model with an outrigger damper system was prepared. The control performance of the outrigger damper system was evaluated by varying stiffness and damping values. On the top floor torsional angle response to the earthquake load, was greatly affected by damping value. And the displacement response was affected greatly by the stiffness value and damping value of damper system. In conclusion, it is necessary to select the proper damping and stiffness values of the outrigger damper system.
        4,000원
        43.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In recent years, an outrigger damper system has been proposed to reduce dynamic responses of tall buildings. However, a study on outrigger damper system is still in its early stages. In this study, time history analysis was performed to investigate the dynamic response control performance of outrigger damper. To do this, a actual scale 3-dimensional tall building model with outrigger damper system has been developed. El Centro earthquake was applied as an earthquake excitation. The control performance of the outrigger damper system was evaluated by varying stiffness and damping values. Analysis results, on the top floor displacement response to the earthquake load, was greatly effected by damping value. And acceleration response greatly was effected by stiffness value of damper system. Therefore, it is necessary to select that proper stiffness and damping values of the outrigger damper system.
        4,000원
        44.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        부가적인 제어장치를 사용하여 구조물 감쇠를 증가시키는 것은 건축물의 풍응답을 제어하기 위해 자주 사용되는 방법 중 하나이다. 본 연구의 목적은 TMD와 AMD의 다중모드응답 제어성능을 비교하는 것이다. 실제 AMD가 설치된 39층 건물을 사용하였으며, 이전 연구에서 시스템식별을 통해 얻어진 모드정보에 따라 수정된 수치해석모델을 사용하였다. AMD 제어력은 속도피드백, 뱅뱅 제어, LQR 알고리즘을 사용하여 결정하였다. 1차 모드의 RMS 응답을 유사한 수준으로 맞추는 조건에서 TMD와 AMD의 고차모드제 어성능을 비교하였다. 그 결과 TMD는 단일 모드에 대해서만 응답을 저감시킬 수 있었으나, AMD는 다중모드 제어가 가능함을 확인하였다.
        4,000원
        45.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, the concept of damped outrigger system has been proposed for tall buildings. But, structural characteristics and design method of this system were not sufficiently investigated to date. In this study, the dynamic response control performance of outrigger damper has been analyzed. To this end, a simplified analysis model with outrigger damper system has been developed. Use the El Centro seismic(1940, NS) analysis was performed. Analysis results, on the top floor displacement response to the earthquake response, did not have a big effect. However, acceleration response control effect was found to be excellent. The increase of outrigger damper capacity usually results in the improved control performance. However, it is necessary to select that proper stiffness and damping values of the outrigger damper system because, the outrigger damper having large capacity is result in heavy financial burden.
        4,000원
        46.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to develop and evaluate an appropriate control device for a purge type controlled atmosphere (CA) storage in Korea. To determine ideal performance, oxygen and carbon dioxide control capability and airtightness were analyzed according to the postharvest management manual of CA storage of Fuji apples. In shortened experiments for CA storage, the condition was delayed CA at 0-0.5oC for three days and stored at 0.1-0.5% carbon dioxide levels for 3 days and then further stored 6 days under 1% carbon dioxide. As a result, the temperature control range of a developed CA container was 0.0-0.5oC, and the relative humidity was more than 90%, except for the defrosting step for the freezer during the storage period. The rate of pressure reduction for the CA container in the negative and positive pressure states was 0.45 and 0.21 mmH2O/min, respectively, and it was twofolds higher than standard airtightness for CA storage. After nitrogen injection, oxygen concentration was achieved at 2%, and carbon dioxide concentration was maintained at 0.1-0.5% for 6 days. Afterwards, carbon dioxide levels were tightly controlled between 0.1-1.0%. These results suggest that a developed purge type CA container could be effective in commercially maintaining the quality of agricultural products.
        4,000원
        47.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Damped outrigger systems have been proposed as a novel energy dissipation system to protect tall buildings from severe earthquakes and strong wind loads. In this study, semi-active damping devices such as magnetorheological (MR) dampers instead of passive dampers are installed vertically between the outrigger and perimeter columns to achieve large and adaptable energy dissipation. Control performance of semi-active outrigger damper system mainly depends on the control algorithm. Fuzzy logic control algorithm was used to generate command voltage sent to MR damper. Genetic algorithm was used to optimize the fuzzy logic controller. An artificial earthquake load was generated for numerical simulation. A simplified numerical model of damped outrigger system was developed. Based on numerical analyses, it has been shown that the semi-active damped outrigger system can effectively reduce both displacement and acceleration responses of the tall building in comparison with a passive outrigger damper system.
        4,000원
        48.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, the concept of damped outrigger system has been proposed for tall buildings. But, structural characteristics and design method of this system were not sufficiently investigated to date. In this study, the dynamic response control performance of outrigger damper has been analyzed. To this end, a simplified analysis model with outrigger damper system has been developed. An artificial wind of 1000 seconds with 0.1 second time steps was generated by using a Kaimal spectrum. Analysis results show that outrigger damper system is more effective up to 20-23% in the control of dynamic response compared to conventional outrigger system. The increase of outrigger damper capacity usually results in the improved control performance. However, it is necessary to select that proper stiffness and damping values of the outrigger damper system because, the outrigger damper having large capacity is result in heavy financial burden.
        4,000원
        49.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 살포비행의 주된 요운동과 순항비행에 대하여 시뮬레이션과 비행실험을 통해 얻은 적정 제어이득을 적용하여, 농용헬리콥터의 수동과 제어비행에서 순항비행 및 요의 행동을 비교하였다. 수동의 경우는 조종간의 입력 즉, 서보의 입력은 그대로 서보의 출력으로 전달되어 헬리콥터의 비행자세와 반응으로 나타나므로 조종자에 있어 높이와 자세를 유지하는데 높은 숙련도와 노력이 필요하였다. 반면 상용제어기의 적용은 기본적인 자세 및 요의 제어를 제공 받으므로 조종자가 살포작업에 편이성을 제공받을 수 있었다. 수동비행에서 요각의 행태는 편류비행의 결과를 보였으나, 제어에서는 목표진행 방위각에서 안정되게 유지되었다. 또한 수동 순항비행에서는 롤 및 피치각의 자세가 숙련된 조종자에 의해 ±6.9°(±0.11 rad) 정도의 롤 및 피치각의 큰 변동폭을 경험하였다. 반면 자세제어 비행에서는 ±2.8°(±0.05 rad) 정도의 안정된 변동폭을 유지하였다. 따라서, 상용제어기를 적용함으로써 요운동으로 방향을 유지하고 순항비행에서 살포높이와 속도를 조절하는데 조종자의 편이성을 제공 할 수 있을 것으로 생각되었다.
        4,300원
        50.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The area of greenhouse heating is 21,202 ha which becomes 42% among the total greenhouse area. As heating fuel, diesel or oil is usually used by 60%, and the heating cost takes 30 to 40% percentage at the greenhouse running. In this study, the pellet fuel heater was developed to replace oil for reducing the burden of greenhouse heating cost. The pellet fuel heater was composed of a conveying grate stoker, which could control temperature precisely like the diesel heater. Diesel and pellet were used for the greenhouse heating, whose calorific values are 9,200 and 3,898 kcal/kg, respectively. As the heating cost due to the saving effect of pellet fuel heater compared with diesel, greenhouse heating cost was reduced by 44% with pellet
        4,000원
        51.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study discusses remote control torch system that is equipped with CO2 double wire reel. The welding machine is 30m away from the wire feeder at the industrial site and the feeder is three to five meters away from the torch. Accordingly, the welders cannot control the current and voltage that meets the welding condition during work when they are working at a place that prevents them from seeing the control panel such as inside a vehicle or tank or at a far work site. They also have no choice but to stop working to change the wire reel when it is completely burned out. Such work suspension resulting from frequent moves to adjust current and voltage as well as replace the wire and subsequent cooling causes welding defects. The study produced a remote control torch equipped with double wire reel by simplifying and streamlining the existing CO2 functions to reduce the troubling issue. The remote control torch equipped with double wire reel and the existing CO2 /MAG welding torch were applied as V-groove butt in the vertical position using 9mm rolled steel for SM50A welding structure. After completion of welding, the condition of welded surface beads went through visual inspection as well as radiographic inspection to analyze the welding quality inside the welded part. The study also evaluated reduction of welding defects, cost saving, the replacing performance against the existing commercial welders and the effect on possible compatibility
        4,000원
        52.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The control delay in seconds per vehicle is the most important traffic operational index to evaluate the level of service of signalized intersections. Thus, it is very critical to calculate accurate control delay because it is used as a basic quantitative evidence for decision makings regarding to investments on traffic facilities. The control delay consists of time-in-queue delay, acceleration delay, and deceleration delay so that it is technically difficult to directly measure it from fields. Thus, diverse analysis tools, including CORSIM, SYNCHRO, T7F, VISTRO, etc. have been utilized so far. However, each analysis tool may use a unique methodology in calculating control delays. Therefore, the estimated values of control delays may be different by the selection of an analysis tool, which has provided difficulties to traffic engineers in making solid judgments. METHODS: This study was initiated to verify the feasibility of diverse analysis tools, including HCM methodology, CORSIM, SYNCHRO, T7F, VISTRO, in calculating control delays by comparing estimated control delays with that measured from a field. RESULTS : As a result, the selected tools produced quite different values of control delay. In addition, the control delay value estimated using a calibrated CORSIM model was closest to that measured from the field. CONCLUSIONS: First, through the in-depth experiment, it was explicitly verified that the estimated values of control delay may depend on the selection of an analysis tool. Second, among the diverse tools, the value of control delay estimated using the calibrated microscopic traffic simulation model was most close to that measured from the field. Conclusively, analysts should take into account the variability of control delay values according to the selection of a tool in the case of signalized intersection analysis.
        4,200원
        53.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In GMAW welding used mostly at the scene of a welding industry, welders can not see control panels in internal welds of vehicles and tanks, and can not adjust the current and voltage properly during the welding, which is caused by distance from the working area. Therefore, welders have to move to control the current and voltage by stopping welding. This, however, can result in the welding defects by momentary cooling. In this research related to the existing GMAW welding methods and the manners with the remote control torch their performances were evaluated by comparing and analyzing the welds of V-type butt using SM50A 6 mm and welding structural rolled steels. As the result of conducting the visual inspection and bending test one by one against the V-type butt welds, the amount of spatter by the remote control torch method showed reducing effects about five times lower and it had a performance that did not affect the weld defects by displaying suitable effects on the bending test of welds. Consequently, the experimental study on the possibility of replacement and compatibility with the existing commercial welder for the remote control torch was performed.
        4,000원
        54.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A research was conducted on Seoul regional elementary, middle, and high school nutritionists to study about their perception of HACCP control standards & performance conditions and sanitation & safety inspection, to seek for more efficient methods of school meals' sanitation system settlement. All surveys were distributed and collected via email. A total of 305 survey papers were collected, and out of these, 300 school results were analyzed. As for CCP 1 performance conditions, 43.3% of the nutritionist put emphasis on temperature control for cooking duration and 71.0% said that they manage both temperature and PHF food control. In CCP 2 stage, 65.8% of the nutritionists maintained the food's temperature, and 56.7% documented the recordings after cooking. A total of 79.3% of the schools scored above 90 points on school meal sanitation & safety inspection, 3.72 points on necessity for revisions, 3.38 points on objectivity, and 3.34 points on reliability. As for these results, a clear CCP control criteria as well as training must be set. Also, because the necessity of revision for sanitation & safety inspection is higher than reliability and objectivity, appropriate complementary measures must be taken.
        4,200원
        55.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        풍진동에 의한 사용성의 문제를 해결하고 진동을 저감시키기 위하여 TLCD가 설치된 건물의 태풍에 의한 풍진동 계측결과를 바탕으로 시스템식별을 통하여 동특성 및 모달풍하중을 추정하고 TLCD의 풍진동 저감성능을 분석하였다. 대상건물은 인천 송도에 위치한 지상 64층 237m의 주거용건물로 상층부에 TLCD가 설치되었으며, 건물과 TLCD의 거동을 계측하기 위하여 풍향풍속계, 가속도계, 수위계및 인터넷기반 송수신시스템을 구축하였다. 계측된 건물의 가속도와 TLCD 액체의 변위결과를 바탕으로 구조물-TLCD 연계 모드를 식별하였으며 이를 바탕으로 구조물과 TLCD의 고유진동수를 식별하였다. 또한 계측된 구조물과 TLCD의 가속도응답으로부터 칼만필터를 이용하여 모달풍하중을 역추정하여 식별된 구조물의 동특성을 바탕으로 TLCD의 풍진동 저감성능을 분석하였다. 분석결과 TLCD의 설치로 인하여 태풍에 의한 풍진동이 최대 29.9% 정도 저감되는 것으로 나타났다.
        4,000원
        56.
        2013.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Recently, functional building materials which are made of sorption materials have been widely used as board products, inorganic paints and wall papers. These remove chemical substances(VOCs, HCHO) from indoor air by physical sorption or chemical reaction and control humidity by capillary condensation. Also these materials have been used as countermeasures to sick building syndrome (SBS). However, in case of using internal building materials, the hazardous substances affecting to indoor air quality are emitted from not only the material itself but also the subsidiary materials such as adhesives for construction. Particularly in case of wallpaper and flooring material, the amount of emission from adhesives for construction is larger than that from the material itself. Therefore, this research tried to develop a technology system that can improve the performance of adsorption, absorption and desorption of moisture including the construction process that can affect to indoor air quality. To attend this end, ‘porous securement manufacturing technology system’ and ‘porous keeping construction technology system’ are developed that can secure more micropores in the process of production and construction of inorganic paint and maintain them. Consequently the reduction performance of chemical substances(VOCs, HCHO) concentrations and the humidity control performance improved almost over 30% by the technology system of the Inorganic paint.
        4,000원
        57.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내·외 기업 간 경쟁의 심화로 인해 근로시간이 증가하면서 일중독 발생 가능성이 높은 환경이 조성되고 있다. 일중독은 일몰입, 일에 대한 강박관념, 일향유감으로 구성된 개념으로, 일중독자일수록 직무성과뿐 아니라 개인의 건강에까지 부정적인 영향을 미칠 수 있다. 그러나 일중독은 성취지향성이 높은 개인의 한 특성을 나타내기도 한다. 따라서 일중독이 가진 부정적·긍정적 효과를 함께 연구할 필요가 있으나 국내에서는 일중독 자체에 대한 연구가 많지 않으며 대부분이 일중독의 부정적 효과에만 초점을 두고 있다. 본 연구는 일중독이 직무성과에 미치는 영향을 검증하여 개인적·조직적 차원의 관리방안을 제시하는데 목적을 두고 있다. 우리나라 대기업과 100억 이상 매출을 가진 중소기업 종사자 218명을 대상으로 실증분석을 한 결과는 다음과 같다. 첫째, 일에 대한 강박관념과 일 향유감이 높아질수록 직무만족은 높아지는 것으로 나타났다. 또한 일 향유감이 높아질수록 이직의도는 낮아지는 것으로 나타났다. 이러한 결과는 선행연구에서 일중독이 부정적 결과만을 유발한다는 것과 달리 긍정적 측면도 있음을 제시한 것이다. 둘째, 일중독이 직무성과에 미치는 부정적 영향은 조직적 차원에서 관리가능한 것으로 나타났다. 즉,일중독 경향이 강한 구성원이라도 조직의 사회적 지원이 있는 경우 직무만족은 향상시키고 이직의도는 감소시켜 직무성과에 긍정적인 영향을 미칠 수 있는 것으로 나타났다. 그러나 사회적 지원은 상황요소를 고려하여 적용할 필요가 있는 것으로 나타났다. 셋째, 일중독과 직무성과간 부정적 관계는 개인적 차원에서도 관리가능한 것으로 나타났다. 즉, 내재론자는 외재론자에 비해 일중독 정도가 높게 나타났다. 그러나 외재론자라 하더라도 일중독의 하위요소 중 일향유감이 높은 경우, 직무에 대한 만족감이 높게 나타났다. 이러한 결과는 조직에서 내재론자에 대한 일중독 관리가 더 필요하며, 나아가 외재론자하더라도 일향유감을 만끽할 수 있도록 일관리를 한다면 성취지향적 업무수행이 가능함을 보여주는 것이다.
        6,300원
        58.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 전하 조절층을 이용하여 녹색 인광 유기발광다이오드의 효율의 향상을 나타냈다. 양극성의 4,4,N,N'-dicarbazolebiphenyl (CBP)를 호스트와 전하 조절층으로 사용하여 발광층 내에서 전하의 이동을 원활하게 할 수 있다. 게다가 전하 조절층의 삽입으로 엑시톤을 효과적으로 발광층 내에 제한하여, 삼중항-삼중항 소멸 현상을 억제할 수 있음을 확인하였다. 발광층의 전체 두께는 유지하고, 전하 조절층의 변화를 준 다섯 개의 소자를 제작하여 최적화된 전하 조절층의 두께를 이용한 Device D는 외부 양자 효율 16.22%와 휘도 효율 55.76 cd/A의 성능을 보였다.
        4,000원
        59.
        2013.06 구독 인증기관 무료, 개인회원 유료
        농용무인 헬리콥터는 벼농사는 물론 전작, 과수 등 소규모 필지의 정밀방제에 이용되고 있으며 농작업의 새로운 패러다임으로 자리 잡고 있다. 본 연구의목적은 농용헬리콥터의 비상시퀀스에서 정지비행 중 측풍에 의해서 비상착륙자리를 이탈하지 않고 위치를 유지하는 편류제어 모듈과 알고리즘의 성능을 평가하는데 있다편류제어의 목적은 비상착륙과 연동되어있는데, 비상조건에 도달하게 되면 호버링을 하면서 비상대처 알고리즘이 작동하게 된다. 그러나 관성 제어 는등속운동에서기체의 움직임을 감지하지 못하게 되고 측풍에 의하여 비상지점으로부터 편류를 하게 되어 착륙 목표지점으로부터 멀어질 수 있다.GPS 모듈을 기초로 개발한 편류제어모듈을 시험하였다.알고리즘 및 실효성을 고려하여 5 m 직경 내에 위치를벗어나지 않는지에 대한 기준을 적용하였다. 초기에는 2~4m/s의 측풍 교란에 대하여 과민하게 반응하였지만 이후5 m직경 내에서 위치를 벗어나지 않고 자세 및 요의 방향을 유지 하였다. 목도의 관찰에서는 전후좌우 흔들림을인지하기 어려운 정도이지만, 데이터에서 보인 편위는GPS 수신기의 특성에 기인하는 것으로 판단한다. 이와같은 편류제어는 비상착륙이나 호버링을 유지하려 할 때의도하지 않는 편류를 제어하는데 사용될 수 있다.
        4,000원
        60.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Material flow control mechanism is a kind of operational policy in manufacturing. It is very important because it varies throughput, throughput time, and work-in-process (WIP) under the same manufacturing resources. Many Researchers have developed various
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