• Smart Structures and Systems
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• 제24권5호
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• pp.617-630
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• 2019

Currently most of the vision-based structural identification research focus either on structural input (vehicle location) estimation or on structural output (structural displacement and strain responses) estimation. The structural condition assessment at global level just with the vision-based structural output cannot give a normalized response irrespective of the type and/or load configurations of the vehicles. Combining the vision-based structural input and the structural output from non-contact sensors overcomes the disadvantage given above, while reducing cost, time, labor force including cable wiring work. In conventional traffic monitoring, sometimes traffic closure is essential for bridge structures, which may cause other severe problems such as traffic jams and accidents. In this study, a completely non-contact structural identification system is proposed, and the system mainly targets the identification of bridge unit influence line (UIL) under operational traffic. Both the structural input (vehicle location information) and output (displacement responses) are obtained by only using cameras and computer vision techniques. Multiple cameras are synchronized by audio signal pattern recognition. The proposed system is verified with a laboratory experiment on a scaled bridge model under a small moving truck load and a field application on a footbridge on campus under a moving golf cart load. The UILs are successfully identified in both bridge cases. The pedestrian loads are also estimated with the extracted UIL and the predicted weights of pedestrians are observed to be in acceptable ranges.

• Smart Structures and Systems
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• 제24권4호
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• pp.459-474
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• 2019

This study develops a novel recursive algorithm to significantly enhance the computation efficiency of a recently proposed stochastic subspace identification (SSI) methodology based on an alternative stabilization diagram. Exemplified by the measurements taken from the two investigated office buildings, it is first demonstrated that merely one sixth of computation time and one fifth of computer memory are required with the new recursive algorithm. Such a progress would enable the realization of on-line and almost real-time monitoring for these two steel framed structures. This recursive SSI algorithm is further applied to analyze 20 months of monitoring data and comprehensively assess the environmental effects. It is certified that the root-mean-square (RMS) response can be utilized as an excellent index to represent most of the environmental effects and its variation strongly correlates with that of the modal frequency. More detailed examination by comparing the monthly correlation coefficient discloses that larger variations in modal frequency induced by greater RMS responses would typically lead to a higher correlation.

• 한국추진공학회지
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• 제17권1호
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• pp.80-88
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• 2013

최근 개발되는 엔진 진단 시스템들은 현장에서 일하는 엔진 정비사들이 이들 시스템들의 복잡성, 비실용성, 공학적 이해부족으로 사용하기가 매우 어렵다. 따라서 실용성 있는 엔진 진단시스템이 요구된다. 본 연구는 작동중인 온라인 성능진단 자료와 기본엔진 성능모델에 의해 계산된 초기고장이 없는 엔진 성능자료와의 비교를 통한 소형엔진의 실용적 성능진단 시스템 개발에 관한 것이다. 또한 제안된 성능진단 시스템은 성능이 저하되거나 고장이 난 엔진으로 간주되는 작동 중 엔진과 고장이 없는 엔진으로 간주되는 기본 엔진 성능모델 사이의 구성품 성능특성을 비교함으로서 가스경로 구성품의 온라인 진단을 확인할 수 있다. 개발된 상태진단시스템은 실제 적용을 용이하게 하기위해 SIMULINK와 LabVIEW프로그램을 이용하여 사용자조건의 GUI형 프로그램으로 작성하였다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2011년도 춘계학술발표대회
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• pp.1218-1221
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• 2011

The development of the internet and information management has enabled new applications which include: Electronic medical record (EMR), intelligent transportation, environmental monitoring, etc. In this paper, we design and implement the Continuity Care Record(CCR) Data Stream management server that compiled with DSMS and DBMS in EMR system for processing, monitoring the incoming CCR data stream and storing the processed result with high-efficiency. The proposed system enables users not only to query stored CCR information from DBMS, but also enables to execute continue query for the real-time CCR Data Stream. By using of CCR Viewer Application users can view or update their personal health records even compare self health care records with standard health care records in order to monitor the healthy status, and the on line updating information would be minimized and medical error.

• Structural Engineering and Mechanics
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• 제19권2호
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• pp.123-139
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• 2005

An automatic modal identification program is developed for continuous extraction of modal parameters of three cable-supported bridges in Hong Kong which are instrumented with a long-term monitoring system. The program employs the Complex Modal Indication Function (CMIF) algorithm for identifying modal properties from continuous ambient vibration measurements in an on-line manner. By using the LabVIEW graphical programming language, the software realizes the algorithm in Virtual Instrument (VI) style. The applicability and implementation issues of the developed software are demonstrated by using one-year measurement data acquired from 67 channels of accelerometers permanently installed on the cable-stayed Ting Kau Bridge. With the continuously identified results, variability in modal vectors due to varying environmental conditions and measurement errors is observed. Such an observation is very helpful for selection of appropriate measured modal vectors for structural health monitoring use.

• Smart Structures and Systems
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• 제8권3호
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• pp.303-320
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• 2011

Comparing to active damage monitoring, impact localization on composite by using time reversal focusing method has several difficulties. First, the transfer function of the actuator-sensor path is difficult to be obtained because of the limitation that no impact experiment is permitted to perform on the real structure and the difficulty to model it because the performance of real aircraft composite is much more complicated comparing to metal structure. Second, the position of impact is unknown and can not be controlled as the excitation signal used in the active monitoring. This makes it not applicable to compare the difference between the excitation and the focused signal. Another difficulty is that impact signal is frequency broadband, giving rise to the difficulty to process virtual synthesis because of the highly dispersion nature of frequency broadband Lamb wave in plate-like structure. Aiming at developing a practical method for on-line localization of impact on aircraft composite structure which can take advantage of time reversal focusing and does not rely on the transfer function, a PZT sensor array based phase synthesis time reversal impact imaging method is proposed. The complex Shannon wavelet transform is presented to extract the frequency narrow-band signals from the impact responded signals of PZT sensors. A phase synthesis process of the frequency narrow-band signals is implemented to search the time reversal focusing position on the structure which represents the impact position. Evaluation experiments on a carbon fiber composite structure show that the proposed method realizes the impact imaging and localization with an error less than 1.5 cm. Discussion of the influence of velocity errors and measurement noise is also given in detail.

• 전력전자학회논문지
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• 제11권6호
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• pp.558-562
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• 2006

현대사회에서 축전지라 불리우는 2차 전지는 그 용도가 중요하지만, 비선형적이고 다양한 파라메타에 따른 복잡한 특성 때문에 그 사용법에 있어서 발전에 제한을 받아왔다. 각 축전지 셀의 건강상태(SOH)를 실시간으로 정확히 파악하는 것은 장비의 안정된 운전과 원활한 관리를 위하여 필수적이다. 본 논문에서는 축전지의 내부컨덕턴스를 측정하는 간접적인 방법에 의하여 장비의 운전이나 축전지의 수명에 영향을 주지 않고 납축전지의 건강상태(SOH)를 실시간으로 진단하는 방법을 제시하고, 실제로 120개의 납축전지에 대한 컨덕턴스 자료에 의하여 건강상태를 진단하고 교체시기를 판단한다.

• 비파괴검사학회지
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• 제23권5호
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• pp.445-454
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• 2003

구조건전성 모니터링은 복합재 구조물이 운용되는 단계에서뿐만 아니라 설계 및 제작단계에서도 중요한 관심사가 되고 있다. 과도한 하중이나 저속충격은 모재균열이나 층간분리와 같은 복합재 파손의 원인이 될 수 있으며 이러한 손상은 구조물의 하중지지성능을 저하시키게 된다. 지능형 복합재 구조물에서의 구조건전성 모니터링기술의 개발은 항공기와 길은 복합재 구조물의 안전성 향상에 도움이 될 수 있다 본 연구에서는 압전세라믹 센서 및 광섬유 센서를 복합재 구조물의 건전성 모니터링에 적용하였으며 파손신호의 특징파악 틴 충격위치 검출을 위한 신호처리 방법을 제안하였다.

• Molecules and Cells
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• 제42권11호
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• pp.783-793
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• 2019

When endoplasmic reticulum (ER) functions are perturbed, the ER induces several signaling pathways called unfolded protein response to reestablish ER homeostasis through three ER transmembrane proteins: inositol-requiring enzyme 1 (IRE1), PKR-like ER kinase (PERK), and activating transcription factor 6 (ATF6). Although it is important to measure the activity of ATF6 that can indicate the status of the ER, no specific cell-based reporter assay is currently available. Here, we report a new cell-based method for monitoring ER stress based on the cleavage of $ATF6{\alpha}$ by sequential actions of proteases at the Golgi apparatus during ER stress. A new expressing vector was constructed by using fusion gene of GAL4 DNA binding domain (GAL4DBD) and activation domain derived from herpes simplex virus VP16 protein (VP16AD) followed by a human $ATF6{\alpha}$ N-terminal deletion variant. During ER stress, the GAL4DBD-VP16AD(GV)-$hATF6{\alpha}$ deletion variant was cleaved to liberate active transcription activator encompassing GV-$hATF6{\alpha}$ fragment which could translocate into the nucleus. The translocated GV-$hATF6{\alpha}$ fragment strongly induced the expression of firefly luciferase in HeLa Luciferase Reporter cell line containing a stably integrated 5X GAL4 site-luciferase gene. The established double stable reporter cell line HLR-GV-$hATF6{\alpha}$(333) represents an innovative tool to investigate regulated intramembrane proteolysis of $ATF6{\alpha}$. It can substitute active pATF6(N) binding motif-based reporter cell lines.

• 전기학회논문지P
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• 제61권1호
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• pp.41-46
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• 2012

Electrolytic power capacitors have been widely used in power conversion system such as inverter or UPS because of characteristics of large capacitance, high-voltage and low-cost. The electrolytic capacitor, which is most of the time affected by the aging effect, plays a very important role for the power-electronics system quality and reliability. Therefore it is important to diagnosis monitoring the condition of an electrolytic capacitor in real-time to predict the failure. In this paper, the on-line remote diagnosis monitoring system for UPS DC link electrolytic capacitors using low-cost single-chip zigbee communication modules is developed. To estimate the health status of the capacitor, the equivalent series resistor(ESR) of the component has to be determined. The capacitor ESR is estimated by using RMS computation using BPF modeling of DC link ripple voltage/current. Zigbee-based hardware experimental results show that the proposed remote capacitor diagnosis monitoring system can be applied to UPS successfully.