• Journal of Biosystems Engineering
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• 제42권4호
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• pp.350-357
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• 2017

Purpose: In-situ monitoring of water quality is fundamental to most environmental applications. The high cost and long delays of conventional laboratory methods used to determine water quality, including on-site sampling and chemical analysis, have limited their use in efficiently managing water sources while preventing environmental pollution. The objective of this study was to develop an on-site water monitoring system consisting mainly of an Arduino board and a sensor array of multiple ion selective electrodes (ISEs) to measure the concentration of $NO_3$ ions. Methods: The developed system includes a combination of three ISEs, double-junction reference electrode, solution container, sampling system consisting of three pumps and solenoid valves, signal processing circuit, and an Arduino board for data acquisition and system control. Prior to each sample measurement, a two-point normalization method was applied for a sensitivity adjustment followed by an offset adjustment to minimize the potential drift that could occur during continuous measurement and standardize the response of multiple electrodes. To investigate its utility in on-site nitrate monitoring, the prototype was tested in a facility where drinking water was collected from a water supply source. Results: Differences in the electric potentials of the $NO_3$ ISEs between 10 and $100mg{\cdot}L^{-1}$ $NO_3$ concentration levels were nearly constant with negative sensitivities of 58 to 62 mV during the period of sample measurement, which is representative of a stable electrode response. The $NO_3$ concentrations determined by the ISEs were almost comparable to those obtained with standard instruments within 15% relative errors. Conclusions: The use of the developed on-site nitrate monitoring system based on automatic sampling and two-point normalization was feasible for detecting abrupt changes in nitrate concentration at various water supply sites, showing a maximum difference of $4.2mg{\cdot}L^{-1}$ from an actual concentration of $14mg{\cdot}L^{-1}$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.529-530
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• 2007

The paper considers the relation between on-line monitoring and diagnostics on the one hand and high-voltage (HV) withstand and partial discharge (PD) on-site testing on the other. HV testing supplies the basic data (fingerprints) for diagnostics. In case of warnings by on-line diagnostic systems, off-line withstand and PD testing delivers the best possible information about defects and enables the classification of the risk. Because alternating voltage (AC) is the most important test voltage, the AC generation on site is considered. Frequency tuned resonant (ACRF) test systems are best adapted to on-site conditions. They can be simply combined with PD measuring equipment. The available ACRF test systems and their application to electric power equipment -from cable systems to power transformers - is described.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.122-122
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• 2017

Recently, environmental problems have become an area of growing interests. In-situ monitoring of water quality is fundamental to most environmental applications. The accurate measurement of nitrate concentrations is fundamental to understanding biogeochemistry in aquatic ecosystems. Several studies have reported that one of the most feasible methods to measure nitrate concentration is the use of Ion Selective-electrodes (ISEs). The ISE application to water monitoring has several advantages, such as direct measurement methodology, high sensitivity, wide measurement range, low cost, and portability. However, the ISE methods may yield inconsistent results where there was a difference in temperature between the calibration and measurement solutions, which is associated with the temperature dependence of ionic activity coefficients in solution. In this study, to investigate the potential of using the combination of a temperature sensor and nitrate ISEs for minimizing the effect of temperature on real-time nitrate sensing in natural water, a prototype of on-site water monitoring system was built, mainly consisting of a sensor chamber, an array of 3 ISEs, an waterproof temperature sensor, an automatic sampling system, and an arduino MCU board. The analog signals of ISEs were obtained using the second-order Sallen-key filter for performing voltage following, differential amplification, and low pass filtering. The performance test of the developed water nitrate sensing system was conducted in a monitoring station of drinking water located in Jeongseon, Kangwon. A temperature compensation method based on two-point normalization was proposed, which incorporated the determination of temperature coefficient values using regression equations relating solution temperature and electrode signal determined in our previous studies.

• Environmental Engineering Research
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• 제23권4호
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• pp.430-441
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• 2018

The adverse health impact of air pollution is becoming more serious. The purpose of this study is twofold: One is to analyze the effect of air pollution and temperatures on human health by analyzing the number of deaths from cardiovascular disease in Seoul, Korea; the other is to determine what impact the location of a monitoring site has on the results of a health study. For this latter purpose, air pollution and temperature monitors are sited at three locations termed green, public, and residential. Then, a decision tree model is used to analyze factors linked with deaths occurring at each monitoring site. The results show that the environmental temperatures before death and the $PM_{2.5}$ concentrations on the day of death are highly linked with the number of deaths regardless of the monitoring location. However, results are most accurate with residential data. The results of this study can be used as base data for a similar analysis and ultimately, as a guide to minimize the health impact of air pollution.

• 국제학술발표논문집
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• The 7th International Conference on Construction Engineering and Project Management Summit Forum on Sustainable Construction and Management
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• pp.252-259
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• 2017

Nowadays, the existing manual method for recording actual progress of the construction site has some drawbacks, such as great reliance on the experience of professional engineers, work-intensive, time consuming and error prone. A method integrating computer vision and BIM(Building Information Modeling) is presented for indoor automatic progress monitoring. The developed method can accurately calculate the engineering quantity of target component in the time-lapse images. Firstly, sample images of on-site target are collected for training the classifier. After the construction images are identified by edge detection and classifier, a voting algorithm based on mathematical geometry and vector operation will divide the target contour. Then, according to the camera calibration principle, the image pixel coordinates are conversed into the real world Coordinate and the real coordinates would be corrected with the help of the geometric information in BIM model. Finally, the actual engineering quantity is calculated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.448-452
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• 2007

Many industrial operations require continuous or nearly-continuous operation of machines, which if interrupted can result in significant financial loss. The condition monitoring of these machines has received considerable attention recent years. Rapid developments in semiconductor, computing, and communication with a remote site have led to a new generation of sensor called "smart" sensors which are capable of wireless communication with a remote site. The purpose of this research is the development of smart sensor using which can on-line perform condition monitoring. This system is addressed to detect conditions that may lead to equipment failure when it is running. Moreover it will reduce condition monitoring expense using low cost MEMS accelerometer. This sensor can receive data in real-time or periodic time from MEMS accelerometer. Furthermore, this system is capable for signal preprocessing task (High Pass Filter, Low Pass Filter and Gain Amplifier) and analog to digital converter (A/D) which is controlled by CPU. A/D converter that converts 10bit digital data is used. This sensor communicates with a remote site PC using TCP/IP protocols. Wireless LAN contain IEEE 802.11i-PSK or WPA (PSK, TKIP) encryption. Developed sensor executes performance tests for data acquisition accuracy estimations.

• Smart Structures and Systems
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• 제30권5호
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• pp.433-446
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• 2022

Despite efforts to reduce unexpected accidents at confined construction sites, choking accidents continue to occur. Because of the poorly ventilated atmosphere, particularly in long, confined underground spaces, workers are subject to dangerous working conditions despite the use of artificial ventilation. Moreover, the traditional monitoring methods of using portable gas detectors place safety inspectors in direct contact with hazardous conditions. In this study, a long-range (LoRa)-based wireless safety monitoring system that features the network organization, fault-tolerant, power management, and a graphical user interface (GUI) was developed for underground construction sites. The LoRa wireless data communication system was adopted to detect hazardous gases and oxygen deficiency within a confined underground space with adjustable communication range and low power consumption. Fault tolerance based on the mapping information of the entire wireless sensor network was particularly implemented to ensure the reliable operation of the monitoring system. Moreover, a sleep mode was implemented for the efficient power management. The GUI was also developed to control the entire safety-monitoring system and to manage the measured data. The developed safety-monitoring system was validated in an indoor testing and at two full-scale water pipeline construction sites.

• 한국환경복원기술학회지
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• 제18권6호
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• pp.227-237
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• 2015

From January 2013 to October 2015, weed invasion control techniques was tested in the test road of Jungbunaeryuk expressway so as to collect preliminary data for the management methods of the upper exterior banking of expressway shoulders. Then, monitoring was conducted and its results are as follows. Mat (sheet), solidifying agent, and mulching (wood chips) were applied for the test and their initial effects of preventing weed invasion were all excellent. It was found that the homogeneity of the wood chip mulching method needs to improve. In the mat method and the mulching method were found to have the most excellent economic feasibility and aesthetics, respectively. The covering degree was found to be the highest at 80% in the control site, followed by the wood chip site at 20% and the solidifying agent site and the non-woven fabric site at 5% each. As for species diversity, the control had the largest variety of species. Two years after the construction, many different species of plants invaded and were growing. Plants including weed didn't tend to invade the slopes applied with non-woven fabric. In addition, weed didn't invade the solidifying agent site and the aesthetics of the upper exterior banking of expressway shoulders was found to be excellent. The wood chip site was found to require consistent management for preventing weed invasion. The mat (sheet) site, the solidifying agent site, and the wood chip mulching site were found to have excellent weed prevention effects. As time passed, the mat (sheet) site and the solidifying agent site showed better weed prevention effects. However, they need consistent monitoring for further application.

• 방사성폐기물학회지
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• 제9권3호
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• pp.149-159
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• 2011

원전 운영자는 계통 및 기기의 열화 등에 의해서 발생할 수 있는 비계획적 방사성물질의 방출로 인한 환경 및 주변 주민에의 영향을 합리적으로 달성 가능한 한 낮게 유지하기 위해서 비계획적 방출을 조기에 감지할 수 있는 부지에 적합한 지하수 감시 프로그램을 수립해야 하며, 이를 위해서는 해당 부지의 수문지질 특성의 파악을 통해 지하수 유동을 평가해야 한다. 본 논문에서는 고리 1호기에서 계획되고 있는 지하수 감시 프로그램에 필요한 자료를 제공하기 위해, 고리 1발전소 부지의 기존 수문지질 조사 및 관련 자료의 조사를 통해 부지 내 지하수 유동특성을 파악하고 이를 바탕으로 가상의 비계획적 방출에 의한 삼중수소의 오염운(汚染雲)의 거동을 모의하였다. 모의 결과 지하수의 주 유동 방향은 남서방향이었으며 지하수의 대부분이 남쪽 및 동쪽 바다로 유입되었다. 삼중수소 오염운 역시 바다로 향하였으나 지하집수조(dewatering sump)에 의해 그 속도가 지연되는 것을 확인할 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1993년도 지반.환경 매립에 관한 학술발표회 논문집
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• pp.28-44
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• 1993

Remediation actions in uncontrolled landfill site should be conducted after the investigation of contamination status and potential health risk or damage. Based on the above, proper control measures should be established and operated. Also continuous monitoring should be followed. In this study, the status of ground water contamination around Nanji Landfill Site was investigated. Monitoring wells were installed around the landfill and ground water was sampled once a month and analyzed. Water quality of each monitoring well was different depending on the horizontal and vertical distance from the landfill, and the seasonal leachate characteristics were not significantly changed because percolating water stayed long time in the deep waste layer. It was predicted that major multivalent cations were mainly precipitated as metal carbonate form, and chemical mass balances (CMBs) could be applied for the apportionment of leachate contamination to ground water quality of surrounding areas of Nanji Landfill. Parameters required to estimate pollutant flux to the receptor near landfill were listed and discussion to get these parameters was made. Finally, based on the above data, control measures of ground water contamination were suggested and discussed.