• Smart Structures and Systems
• /
• 제26권1호
• /
• pp.11-21
• /
• 2020

The hinge joint is the key to the overall cooperative working performance of the assembled beam bridge, and it is also the weakest part during the service period. This paper proposes a method for monitoring and evaluating the lateral cooperative working performance of fabricated beam bridges based on dynamic strain correlation coefficient indicator. This method is suitable for monitoring and evaluation of hinge joints status between prefabricated girders and overall cooperative working performance of bridge, without interruption of traffic and easy implementation. The remote cloud monitoring and diagnosis system was designed and implemented on a real assembled beam bridge. The algorithms of data preprocessing, online indicator extraction and status diagnosis were given, and the corresponding software platform and scientific computing environment for cloud operation were developed. Through the analysis of real bridge monitoring data, the effectiveness and accuracy of the method are proved and it can be used in the health monitoring system of such bridges.

• 한국지반공학회논문집
• /
• 제39권9호
• /
• pp.51-61
• /
• 2023

본 연구의 목적은 보 구조물 기초지반의 파이핑 안정성을 모니터링할 수 있는 지표를 선정하고, 선정 지표를 활용한 파이핑 안정성 모니터링 방법을 제시하는 데에 있다. 기존 연구 결과에 대한 검토와 침투모사 수치해석 결과로부터 보 기초지반에서의 간극수압 변화를 파이핑 모니터링 지표로 선정하였다. 운영 중인 보에서 간극수압계의 설치 상황을 감안하여, 간극수압계가 보 기초 하부에 1개 또는 2개 설치된 경우 각각에 대해, 다양한 상류 저수위 조건에 따른 침투해석을 수행하였다. 침투해석 결과로부터 파이핑 모니터링 방안을 이러한 각각의 경우에 대하여 제안하였다. 아울러, 제안된 모니터링 방안을 운영 중인 보에 시범 적용하였고 이를 통해 그 실효성을 확인하였다.

• 보존과학연구
• /
• 통권31호
• /
• pp.59-68
• /
• 2010

Cultural heritages are damaged by surrounding several environmental factors. Main factors are temperature, humidity, light, atmosphere and indoor pollutant, organism, etc. Therefore, to prevent damage of cultural heritage from such environmental factor, conservation environment monitoring becomes more important. Indicator is one of the simple method for environment monitoring. It can be used without expensive and complex equipments. However, it should be performed scientific examination for application to cultural heritage. In this study, some Temperature Indicators were chosen and reliability assessment was carried out for application to cultural heritage. Brightness($L^*$) is selected for reliability assessment factor. As a result of lab test, Temperature Indicators were not influenced greatly in humidity change. When they were exposed to setting temperature, the color was changed in setting temperature area and ${\pm}2^{\circ}C$ part of setting temperature. Especially brightness value was high in setting temperature area. Also, Temperature Indicators were stabilized after about 16 minutes when were exposed to temperature difference of $10^{\circ}C$ and when temperature difference with exposure environment is smaller, stabilization time shortened. Therefore, it is a possible to confirm that selected Temperature Indicator is reliable product through measurement of color difference value and naked eye observation.

• 한국농공학회논문집
• /
• 제47권4호
• /
• pp.75-85
• /
• 2005

A study was performed to examine the effects of reclaimed-water irrigation on microorganism con-centration in ponded-water of paddy rice plots. Several treatments were used and each one was triplicated to evaluate the change of indicator microorganisms (total coliforms (TC), fecal coliforms FC), and E. coli) concentrations in 2003 and 2004 growing seasons. Their concentrations increased significantly right after irrigation, but decreased about $45\%$ in 24 hours. It implies that agricultural activities such as plowing and fertilizing should be practiced one or two days after irrigation considering health-risks. Treatments with UV-disinfected water irrigation demonstrated significantly lower concentrations than others including control plots where natural surface water was irrigated. The monitoring results from actual paddy rice fields and experimental paddy plots showed that concentrations of indicator microorganisms ranged from $10^2\;to\;10^5$ MPN/100mL. A comprehensive assessment of existing agricultural practices and a thorough monitoring in the field as well as treatment-plots are recommended to make more realistic national guidelines more applicable. UV-disinfected water irrigation reduced microorganism concentrations in paddy fields down to below the concentration of conventional paddy rice culture, and is thought to be an effective and feasible measure fur agricultural reuse of secondary effluent.

• Smart Structures and Systems
• /
• 제21권3호
• /
• pp.287-303
• /
• 2018

Applications of energy harvesting from mechanical vibrations is becoming popular but the full potential of such applications is yet to be explored. This paper addresses this issue by considering an application of energy harvesting for the dual objective of serving as an indicator of structural health monitoring (SHM) and extent of control. Variation of harvested energy from an undamaged baseline is employed for this purpose and the concept is illustrated by implementing it for active vibrations of a pipe structure. Theoretical and experimental analyses are carried out to determine the energy harvesting potential from undamaged and damaged conditions. The use of energy harvesting as indicator for control is subsequently investigated, considering the effect of the introduction of a tuned mass damper (TMD). It is found that energy harvesting can be used for the detection and monitoring of the location and magnitude of damage occurring within a pipe structure. Additionally, the harvested energy acts as an indicator of the extent of reduction of vibration of pipes when a TMD is attached. This paper extends the range of applications of energy harvesting devices for the monitoring of built infrastructure and illustrates the vast potential of energy harvesters as smart sensors.

• Structural Monitoring and Maintenance
• /
• 제6권3호
• /
• pp.219-235
• /
• 2019

Scheduled inspections of common crossings are one of the main cost drivers of railway maintenance. Prognostics and health management (PHM) approach and modern monitoring means offer many possibilities in the optimization of inspections and maintenance. The present paper deals with data driven prognosis of the common crossing remaining useful life (RUL) that is based on an inertial monitoring system. The problem of scheduled inspections system for common crossings is outlined and analysed. The proposed analysis of inertial signals with the maximal overlap discrete wavelet packet transform (MODWPT) and Shannon entropy (SE) estimates enable to extract the spectral features. The relevant features for the acceleration components are selected with application of Lasso (Least absolute shrinkage and selection operator) regularization. The features are fused with time domain information about the longitudinal position of wheels impact and train velocities by multivariate regression. The fused structural health (SH) indicator has a significant correlation to the lifetime of crossing. The RUL prognosis is performed on the linear degradation stochastic model with recursive Bayesian update. Prognosis testing metrics show the promising results for common crossing inspection scheduling improvement.

• 국제학술발표논문집
• /
• The 6th International Conference on Construction Engineering and Project Management
• /
• pp.354-356
• /
• 2015

As domestic recession has had an adverse impact on many Korean companies in Korea, financial soundness has become a critical issues. It is essential to identify financial risk factors to prevent workout as well as to improve the financial condition of domestic construction companies. Therefore, this study derived important management indicators and the financial ratios that belong to each indicator through a comparative analysis between healthy companies and workout companies with financial statement. As a consequence, key financial ratios are derived into 3 of 25 ratios; Equity Ratio in stability indicator, Total Asset Turnover Ratio in activity indicator, and Labor Equipment Ratio in productivity indicator. So, Korean construction firms are required close monitoring these critical financial ratios indicating variation between construction companies which have opposing statuses in finance in order to keep sound financial condition and increase productivity.

• 정보보호학회논문지
• /
• 제22권3호
• /
• pp.637-644
• /
• 2012

오늘날과 같은 정보화 사회에서는 정보가 기업의 핵심자산으로 인식되고 있으며, 특히 금융권에서는 고객의 개인정보 유출이 커다란 이슈로 대두되고 있다. 현재 상용화된 개인정보보호 기술은 전사적인 차원이 아닌 일부 기능으로 국한되거나 극히 일부분의 개인정보만 포함되는 경우가 많다. 따라서 전사적인 차원에서 개인정보 유출을 사전에 예방하기 위해서는 개인정보 유출의 징후를 지속적으로 모니터링 할 수 있는 체계에 대한 연구가 필요하다. 본 연구에서는 개인정보 접근에 대한 패턴분석 및 SRI(Security Risk Indicator)를 이용한 모니터링 체계 구축 방법론을 제안하였으며, 실제 금융권 기업에 적용하여 사례 연구를 수행하였다. 이를 통해 탐지된 개인정보 유출 시도는 탐지된 유형에 맞춰 체계화된 대응 방안을 수립할 수 있게 되었다.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 2000년도 추계학술대회 학술발표 논문집
• /
• pp.393-398
• /
• 2000

In this paper, we propose an Intelligent Monitoring Network System(IMNS) for the truck scale balance system. Truck scale balance system consis of three parts; Load cell part, Indicator part, and Junction box part. IMNS is attached to Junction box in truck scale balance system. Even if Load cell have been some problems, a truck scale balance system still has been run to determine, the values involved error. Therefore prosed system is has concentrated on Load cell part. Other Parts have been changed a portion of circuit for monitoring system.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 추계종합학술대회 논문집(3)
• /
• pp.41-44
• /
• 2000

In this paper, we propose an Intelligent Monitoring Network System(IMNS) for The truck scale balance system. Truck scale balance system consis of three parts； Load cell part, Indicator part, and Junction box part. IMNS is attached to Junction box in truck scale balance system. Even if Load cell have been some problems, a truck scale balance system still has been run to determine, the values involved error. therefore prosed system is has concentrated on Load cell part. Other Parts have been changed a portion of circuit for monitoring system.