• 한국안전학회지
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• 제33권3호
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• pp.27-32
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• 2018

Nowadays, to prevent electrical accidents in Korea, inspectors directly performed checking general electrical facilities as a cycle from every one to three years. It is difficult to presuppose an omen because intact conditions of electrical equipments are not kept at the time of inspection. In this paper, in order to ensure effectiveness of an online basis electric inspection, we developed an electrical safety IoT system using LoRa communication technology to enable monitoring mainly electrical safety components such as overcurrent, overvoltage, resistive leakage current, and power. Then we proposed a method for verifying performances of the prosed electrical safety IoT system. Resistive leakage currents are calculated by using difference of phase between voltages and currents. We verified that average errors are 0.97%, which reference goal is ${\pm}5%$ for a device, through reliability test according to conditions. Results of this research can be used as basic study materials to develop technologies for measuring three phase leakage current and for implementing public electrical safety. platform.

• 대한안전경영과학회지
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• 제22권1호
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• pp.15-21
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• 2020

Industrial Motors diagnostic equipment is highly dependent on the automation system, so if there are defects in the automation equipment, it can only rely on the operator's intuitive judgment.To help with intuitive judgment, Park's Vactor Approach(PVA) represents the current signal as a pattern of circles, so it can tell if a fault occurs when the circle is distorted. However, the failure to judge the degree of distortion of the circle pattern is the basis of the fault, so it will face difficulties. In this paper, in order to compare the faults of PVA, the period of d-axis current of PVA pulsation was mastered, so that two phase differences occurred in the same signal source. Through experiments, it is confirmed that this is a 90 degree cross formation of PVA, which is convenient for judging from the vision that there is no fault, thus helping the operator to make intuitive judgment.

• Smart Structures and Systems
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• 제33권3호
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• pp.227-241
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• 2024

Safety and structural integrity of civil structures, like bridges and buildings, can be substantially enhanced by employing appropriate structural health monitoring (SHM) techniques for timely diagnosis of incipient damages. The information gathered from health monitoring of important infrastructure helps in making informed decisions on their maintenance. This ensures smooth, uninterrupted operation of the civil infrastructure and also cuts down the overall maintenance cost. With an early warning system, SHM can protect human life during major structural failures. A real-time online damage localization technique is proposed using only the vibration measurements in this paper. The concept of the 'Degree of Scatter' (DoS) of the vibration measurements is used to generate a spatial profile, and fractal dimension theory is used for damage detection and localization in the proposed two-phase algorithm. Further, it ensures robustness against environmental and operational variability (EoV). The proposed method works only with output-only responses and does not require correlated finite element models. Investigations are carried out to test the presented algorithm, using the synthetic data generated from a simply supported beam, a 25-storey shear building model, and also experimental data obtained from the lab-level experiments on a steel I-beam and a ten-storey framed structure. The investigations suggest that the proposed damage localization algorithm is capable of isolating the influence of the confounding factors associated with EoV while detecting and localizing damage even with noisy measurements.

• 대한지역사회영양학회지
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• 제22권5호
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• pp.401-412
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• 2017

Objectives: The purpose of this study was to investigate the current status of parents' monitoring of school lunch programs and to examine the relationship of parents' school lunch monitoring with their level of trust in school lunch programs. Methods: During November 2016, a web survey was conducted with 1,283 parents who had participated in monitoring of school lunch programs. A total of 621 parents completed the questionnaires (48.4% response rate) and the responses from 442 parents were analyzed (34.5% analysis rate) for elementary (n=196) and middle/high school parents (n=246), respectively. Results: Both the elementary and middle/high school parents most wanted to participate in monitoring 1~2 times per month, which was less frequent than their current practice. They showed the highest experience rate in 'food sanitation' area in both the prior training and actual practice of school lunch monitoring. They most responded 'increasing trust in school lunch programs' as a merit and 'lack of parents participating in monitoring' as a problem of school lunch monitoring. The average levels of trust did not differ between elementary and middle/high school parents. Multiple regression analyses showed that elementary school parents' level of satisfaction in the monitored school lunch programs was positively associated with the parents' level of trust in general school lunch programs. Monitoring frequency and parents' age, in addition to level of satisfaction in the monitored school lunch program, were associated with level of trust in general school lunch programs among middle/high school parents. Conclusions: There was room for change in parents' school lunch monitoring programs to meet parents' needs better. Well-managed school lunch monitoring programs contributing to parents' satisfaction with school lunch programs could increase parents' level of trust in school lunch programs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.570-571
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• 2011

CTMS(Compact Tower Online Monitoring System), which deals with the polymer insulation arms of new material, is the on-line monitoring system for verifying stability and reliability of a new Compact Tower. CTMS measures real time data from the installed sensors in a Compact Tower and transmission line, air craft warning lights for detecting and determining the life time and the replace cycle of these facilities. This paper introduces how develop the CTMS and proposes how it will be use.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.441-442
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• 2010

본 연구는 최근 국내 초고층 건물이나 초장대 교량에 쓰이는 고강도 콘크리트의 강도 발현을 임피던스 계측을 통해 발현된 강도를 모니터링 하는 시스템을 개발하고 무선 센서를 이용하여 현장에서 실시간으로 측정할 수 있는 시스템을 개발하는데 그 목적을 두었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.1326-1330
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• 2004

This study analyzes the rubber-dam of hydrologic character to be located in a Nagdong-river main stream in Dasamyeon Juggogli of the Dae-gu global city lot the river environment monitoring. The purpose of this research investigates the influence according to the rubber-dam install scientificly. A result natural disposition, prepare the gauge to matte the width of the area of the understanding and the computation of the rating which Apply is possible. Into the result of this research, $Q=898.8h^2-26126h+189886$ edge was computed to the rating. Also this study use the now rate to get for an upside expression and analysis a water balance. Through the officer to be efficient a hereafter seminar zero and processing of the data to be acquired, the supplementation so that this study can share the data to the online. High practical use of the The self-governinig body of the data and data confirmed report which loses in the trust will be achieved.

• Ocean Systems Engineering
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• 제1권1호
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• pp.59-72
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• 2011

The objective of this work is to investigate the possibility of using the longitudinal strain on the surface of a pipe to determine the inception of dangerous free spanning. The long term objective is to develop an online monitoring technique to detect the development of dangerous free spanning in subsea pipelines. This work involves experimental study as well as finite element modeling. In the experiments, the strains at four points on a cross section of a pipeline inside the free span zone are measured. Pipes with different boundary conditions and different diameter to length ratios were tested. The pipe is treated as a simple beam with fixed-fixed or simply supported boundary conditions. The variation of the strains as a function of the diameter to length ratio gives a pointer to the inception of dangerous free spanning. The finite element results agree qualitatively with the experiments. The quantitative discrepancy is a result of the difficulty to replicate the exact boundary conditions that is used by the finite element program.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.900-904
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• 2009

The measurement of contact wire uplift in electric railway is one of the most test method to accept the maximum permitted speed of new vehicles or pantographs. The contact wire uplift can be measured for shot periods when pantograph is running in monitoring station. This paper describes the development of two different methods for contact uplift measurement using vision-based system and wireless online monitoring system. Our vision-based system employs a high-speed CMOS (Complementary Metal Oxide Semiconductor) camera with gigabit ethernet LAN. The development of a real-time remote monitoring system that acquires data from any kind of sensor to be transmitted by wireless communication from overhead line and structure at 25 kV to a computer in catenary system. The proposed two kind of different measurement systems to evaluation for dynamic uplift of overhead contact wire shows promising on-field applications for high speed train such as Korea Tilting Train (TTX) and Korea Train eXpress (KTX).

• 조명전기설비학회논문지
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• 제26권10호
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• pp.72-80
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• 2012

In general, electronic conveyor scales are installed in a relatively distributed manner on the crushed rock and sand production site. It is one of the time-consuming and difficult engineering works to monitor and control the plant operation status such as the management of measuring data, malfunction of belt conveyor, and fault of electronic conveyor scale. Therefore, to alleviate the inefficient problems and to monitor the operating plant in the online and remote control room, a remote calibration and real-time monitoring system, which is practically applied to the electronic conveyor scale system and verified by onsite experiment, is developed based on the LabVIEW.