• 비파괴검사학회지
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• 제22권3호
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• pp.239-245
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• 2002

현재까지 다양한 토목구조물들은 여러 가지 요인에 의한 노후화와 축척된 손상에도 불구하고 별다른 조치 없이 계속해서 사용되고 있었다. 따라서, 이러한 구조물들의 효율적인 유지관리를 유해 계측관리가 중요시되었다. 이에 본 논문에서는 비파괴계측에 의해 사장교의 실시간 계측모니터링시스템을 개발하고자 하며 이를 통해 교량의 안전관리를 하고자 하였다. 계측모니터링시스템은 교량의 유지관리를 도모하고, 교량 관리의 경제적 비용을 줄이게 되며 사장교의 새로운 설계 및 분석방법을 개발하는데 중요한 데이터를 제공할 것이다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.595-601
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• 2003

For monitoring of the civil and building structure, optical fiber sensors are very convenient. The fiber sensors are very small and do not disturb the structural properties. They also have several merits such as electro-magnetic immunity, long signal transmission, good accuracy and multiplicity of one sensor line. Strain measurement technologies with fiber optic sensors have been investigated as a part of smart structure. In this paper, we investigated the possibilities of fiber optic sensor application to the monitoring of beam-column joints of structures. We expect that the fiber optic sensors replace electrical strain gauges. The commercial electric strain gauges show good stability und dominate tile strain measurement market. However, they lack durability and long term stability for continuous monitoring of the structures. In order to apply the strain gauges, we only have to attach them to the surfaces of the structures. In this paper, we investigate the possibility of using fiber optic Bragg grating sensors to joint structure. The sensors show nice response to the structural behavior of the joint.

• Smart Structures and Systems
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• 제6권3호
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• pp.239-262
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• 2010

Tube Lines has carried out a "knowledge and investigation programme" on the deep tube tunnels comprising the Jubilee, Northern and Piccadilly lines, as required by the PPP contract with London Underground. Many of the tunnels have been in use for over 100 years, so this assessment was considered essential to the future safe functioning of the system. This programme has involved a number of generic investigations which guide the assessment methodology and the analysis of some 5,000 individual structures. A significant amount of investigation has been carried out, including ultrasonic thickness measurement, detection of brickwork laminations using radar, stress measurement using magnetic techniques, determination of soil parameters using CPT, pressuremeter and laboratory testing, installation of piezometers, material and tunnel segment testing, and trialling of remote photographic techniques for inspection of large tunnels and shafts. Vibrating wire, potentiometer, electro level, optical and fibre-optic monitoring has been used, and laser measurement and laser scanning has been employed to measure tunnel circularity. It is considered that there is scope for considerable improvements in non-destructive testing technology for structural assessment in particular, and some ideas are offered as a "wish-list". Assessment reports have now been produced for all assets forming Tube Lines' deep tube tunnel network. For assets which are non-compliant with London Underground standards, the risk to the operating railway has to be maintained as low as reasonably practicable (ALARP) using enhanced inspection and monitoring, or repair where required. Monitoring techniques have developed greatly during recent years and further advances will continue to support the economic whole life asset management of infrastructure networks.

• Smart Structures and Systems
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• 제25권3호
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• pp.285-299
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• 2020

Long term structural health monitoring has gained wide attention among civil engineers in recent years due to the scale and severity of infrastructure deterioration. Establishing effective damage indicators and proposing enhanced monitoring methods are of great interests to the engineering practices. In the case of bridge health monitoring, long term structural vibration measurement has been acknowledged to be quite useful and utilized in the planning of maintenance works. Previous researches are majorly concentrated on linear time series models for the measurement, whereas nonlinear dependences among the measurement are not carefully considered. In this paper, a new bridge health monitoring method is proposed based on the use of long term vibration measurement. A combination of the fundamental ARMA model and copula theory is investigated for the first time in detecting bridge structural damages. The concept is applied to a real engineering practice in Japan. The efficiency and accuracy of the copula based damage indicator is analyzed and compared in different window sizes. The performance of the copula based indicator is discussed based on the damage detection rate between the intact structural condition and the damaged structural condition.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.717-723
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• 2002

Recently, the interest in safety assessment of civil infrastructures is increasing in Korea. Especially, as bridge structures become large-scale, it is necessary to monitor and maintain the safety state of bridges, which requires the monitoring system that can make a long-term measurement during the service time of bridge. In this paper, advanced fiber optic sensors for long-term measurement, setup techniques of bridge monitoring system and the assessment of measured data are introduced. Attached or embedded optical fiber sensors to structural members of small and big structures including Sung San Bridge are surveyed. For the Sung San Bridge, the responses of the fiber optic sensors by 30 ton weigh truck loads with various speeds ate measured. Monitoring system is also applied to the mock-up of bridges. The monitoring capability of the advanced fiber optic sensor system was confirmed.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권2호
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• pp.136-140
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• 2011

Monitoring of water surfaces through permanent measurement of hydrodynamic and meteorological data is one of the main requirements in safe and sustainable water management. The Caspian Sea, the major surface water body in Iran, significantly affects more than 600 km of urban and industrial coastline. In the present work, an integrated marine monitoring network for the entire southern coastline of the Caspian Sea was developed. The main design concerns centered on the network measuring components and data recording, checking, filtering, gap recognition, and transferring systems. Four coastal monitoring stations were assigned, along with two regional collecting stations and one central data station for gathering, checking and delivering recorded data at different access levels. Applicable guidelines on selection of measuring devices for both shallow and deep water zones are presented herein.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권1호
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• pp.20-25
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• 2006

We suggest a novel temperature detection method utilized in temperature monitoring system. Suggested method detects temperature variation by using $R_{ds(on)}$ characteristics of MOSFET, while conventional methods are using extra devices such as a temperature sensor or an over-temperature detection transistor. For voltage detection between drain and source, 10 bits resolution ADC is needed. Therefore possible measurement signal range is about ten mV. If detected temperature's voltage exceed protection temperature's voltage then controller generates OT (Over Temperature) signal to stop MOSFET's trigger signal. Whole process of measurement is controlled by software. Experimental results show that the developed temperature monitoring system can provide the suitable temperature monitoring method and difference between detected and data sheet value of the suggested system is about $3\%$.

• 한국전자파학회논문지
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• 제16권3호
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• pp.277-285
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• 2005

본 논문은 감시국에서 99 $\%$ 점유 대역폭 측정을 효율적으로 측정 하기 위한 점유 대역폭 측정 방법을 제안한다. 제안된 측정법을 통해 얻어진 측정 결과의 타당성을 확인하기 위해 ATSC DTV 신호에 적용할 수 있는 MACPR을 정의하였다. MACPR은 감시국의 측정 지역을 선정하는데 적합한 측정 파라미터이다. 본 논문의 측정 결과, MACPR$\geq$35 dB 되는 지역 에서 600번 이상을 반복 측정 한다면, ATSC DTV 신호의 효율적인 점유 대역폭 측정이 가능하다는 결론을 얻었다. 본 논문은 제안된 측정 절차를 보여주고, 실제 필드 환경에서 제안한 효율적인 점유 대역폭 측정 방법을 적용하고 증명하였다.

• 한국안전학회지
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• 제25권2호
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• pp.29-34
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• 2010

This paper is aimed to develop monitoring software for detecting the characteristics of current and voltage signals for series arc on electric wire. In order to attain this purpose, the characteristics of series arc were analyzed by the current and voltage signals on electric wire which were installed, and also analyzed by the changes of RMS, instantaneous of waveform value in time domain and THD in frequency domain. Monitoring program which analyze the signal was developed by Labview which can analyze in time domain and frequency domain, and save data. Experimental setup for detecting verification of monitoring program was composed loads of a lamp, an electric heater and an electric fan loads which were usually using. Measurement points for detecting verification of monitoring program were selected at both the panel board and the arc generator at the same time. As results of the experiments by monitoring program, the arc current waveform showed the same characteristic in all measurement points of all load. But the arc voltage waveform was different in each measurement point. When arc occurred, the THD of current value increased above 20%. The results of this study will be effectively used in developing the preventive system of electric fire by series arc.

• Journal of Advanced Marine Engineering and Technology
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• 제35권6호
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• pp.829-834
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• 2011

본 논문에서는 대형 선박용 디젤 엔진의 실린더 라이너의 마모량을 측정하는 새로운 시스템의 개발에 관하여 소개한다. 제안된 시스템은 LVDT, 온도센서, 실린더 내부의 밝기조절용 LED 및 카메라가 각각 1개씩 부착된 측정부, 계측명령전달 및 측정데이터 모니터링을 담당하는 컴퓨터기반 모니터링부, 측정부의 제어 및 측정데이터의 모니터링부로의 전송을 담당하는 주 제어부로 구성된다. 개발된 시스템의 정도는 1/100 mm 의 측정정도를 갖는 내경게이지의 것과 비교되어진다.