• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.221-224
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• 2001

In connection with the monitoring of insulation degradation of large power apparatus in order to predict their unexpected service failures, a statistical treatment, such as phase resolved partial discharge analysis(PRPDA), has been established for the on-line monitoring system during the past decades. However, this method has shown some inconveniences to distinguish the nature of the PD source in power apparatus. In this regard, a novel approach based on the chaotic analysis(CAPD) is proposed describing the fundamental ideas, outcomes and different view points from conventional PRPDA. In order to make a model for the possible defects causing sudden failures in service, several types of specimen were prepared. And partial discharge signals, originated from those samples, were measured and analysed by means of PRPDA and CAPD respectively. Throughout this paper, it seems that the correlation between the consecutive PD pulses depending on the nature of PD could be investigated by CAPD. Therefore, it could be considered that the nature of PD source can be distinguished more distinctively when the PRPDA is combined with CAPD.

• Smart Structures and Systems
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• v.17 no.4
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• pp.631-646
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• 2016

Although the deployment of wireless sensors for structural sensing and monitoring is becoming popular, supplying power to these sensors remains as a daunting task. To address this issue, there have been large volume of ongoing energy harvesting studies that aimed to find a way to scavenge energy from surrounding ambient energy sources such as vibration, light and heat. In this study, a magnetic resonance based wireless power transfer (MR-WPT) system is proposed so that sensors inside a concrete structure can be wirelessly powered by an external power source. MR-WPT system offers need-based active power transfer using an external power source, and allows wireless power transfer through 300-mm thick reinforced concrete with 21.34% and 17.29% transfer efficiency at distances of 450 mm and 500 mm, respectively. Because enough power to operate a typical wireless sensor can be instantaneously transferred using the proposed MR-WPT system, no additional energy storage devices such as rechargeable batteries or supercapacitors are required inside the wireless sensor, extending the expected life-span of the sensor.

• Journal of the Korean Dietetic Association
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• v.12 no.2
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• pp.185-199
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• 2006

The purpose of this study was to estimate the sites providing accurate and useful informations to the public by monitoring food and nutrition informations distributed through the internet quantitatively about 13 items of 7 necessary requisites. Total of 457 internet sites on the searching engines of Yahoo, Empas, Nate, Naver and Daum were monitored by 10 panels from May, 2004 to October. Thirty eight % of the sites got 7 & 8 total of 14 points and total sites showed a normal distribution. From the estimation of meta data, individual sites(5.19) were operated insufficiently compared with the commercial sites(6.10) and institutional sites(6.60) (p<0.000). According to administrators, sites were evaluated in the order of research institute> government organization> academic association> pharmaceutical company, club, food company, university> hospital> individual (p<0.000). While low-ranked sites were lack of authority because they didn't show the information provider and source, high-ranked ones lack of sustainable management(updating informations) and security. From this study, we suggest that 1) theme, contents and design have to prepared with variety to suit the need of target clients instead of that of site operator; 2) source and origin of information have to be provided; 3) informations have to be updated often and site to be managed sustainably.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.3
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• pp.115-127
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• 1997

Nonpoint source (NPS) pollution from small watersheds has recently been brought into attention as a potential pollutant to streams and tnbutaries, as majority of them are experiencing water quality degradation. This necessiates the quantification of NPS loadings from agricultural and forested lands. And this study attempts to quantify daily loadings from forested and farm lands using hydrologic and water quality monitoring. The hydrologic monitoring program consists of five water level gauging stations along creeks and stream at the Banweol reservoir watershed having 1220 hectare in size. Water sam pies were taken and analyzeel periodically at the streamf low gaging sites and tributaries. Soil samples were also taken and the chemical constitutes analyzed. The primary results indicate that the major sources of pollution were small villages and dairy farms on the watersheds, constituting two-third of total nutrient loadings to the reservoir. However, the loadings from paddies and upland areas may cause a problem to the water quality of the reservoir and stream as the measured levels of total nitrogen and phosporus are not low enough to ignore. Further studies are needed to quantify the effects of landuses and treatments at a watershed scale.

• Journal of Environmental Science International
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• v.19 no.7
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• pp.819-827
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• 2010

This study was conducted to investigate runoff characteristics of non-point pollutants source at the urban area in boeun area, Chungbuk Province. The monitoring site covering the watershed of $2.11\;km^2$ contains about 40.3 % of total watershed with the urban area. The monitoring was conducted with six events for five months and Event Mean Concentration(EMC) and Site Mean Concentration(SMC) of SS, BOD, CODMn, T-N, T-P were calculated on the result of the water quality parameters. As a result of the comparion between Arithmetic Mean Concentration and Event Mean Concentration, it showed that over all Event Mean Concentration was higher than Arithmetic Mean Concentration. And it showed that SS, BOD, T-P featured the first-flushing effect, showing relatively high concentration in early-stage storm event.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.5-8
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• 2019

Recently, we have been demanding the comfort of the indoor environment due to environmental problems such as fine dust and yellow dust. In addition it is pursuing the most pleasant indoor environment for humans. In this study, we designed and implemented monitoring systems and mobile applications to enable information such as room temperature and humidity. Open source software and open source hardware are required to design and implement the systems proposed in this study. In this study, the systems implemented used a bluetooth module, a light sensor, and a temperature and humidity sensor. In the future, we expect to be a basic study of systems that can operate dehumidifiers, warm-air fans, fans and humidifiers using motors and optimize indoor environment.

• Journal of IKEEE
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• v.24 no.4
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• pp.1129-1135
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• 2020

The effects of battery aging limit the rechargeable capacity, State of Health(SoH). It is very important to estimate the SoH in the battery monitoring system(BMS) and many algorithms of measuring the internal resistance of the battery were proposed. A method is used by applying a current source of a specific frequency to the battery and measuring the voltage response. When charging harmonic noise is generated in the voltage response, it results in poor resistance measurement accuracy. In this paper, a robust battery internal resistance measurement algorithm is proposed to eliminate the effect of charging noise by integrating the current source and voltage response signals for a certain period. It showed excellent accuracy and stable measurement results. Applying to the BMS for uninterruptible power supply, the usefulness of the proposed method is verified.

• Journal of Sensor Science and Technology
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• v.32 no.2
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• pp.75-81
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• 2023

The significance of gas sensors has been emphasized in various industries and applications, owing to the growing significance of environmental, social, and governance (ESG) management in corporate operations. In particular, the monitoring of hazardous gas leakages and detection of fugitive emissions have recently garnered significant attention across several industrial sectors. As industrial workplaces evolve to ensure the safety of their working environments and reduce greenhouse gas emissions, the demand for high-performance gas sensors in industrial sectors dealing with toxic substances is on the rise. However, conventional gas-sensing systems have limitations in monitoring fugitive gas leakages at both critical and subcritical concentrations in complex environments. To overcome these difficulties, recent studies in the field of gas sensors have employed techniques such as mobile robotic olfaction, remote optical sensing, chemical grid sensing, and remote acoustic sensing. This review highlights the significant progress made in various technologies that have enabled accurate and real-time mapping of gas distribution and localization of hazardous gas sources. These recent advancements in gas-sensing technology have shed light on the future role of gas-detection systems in industrial safety.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.1
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• pp.34-39
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• 2018

Along with the development of ICT technology, wearable devices of various sizes and shapes have been developed. In addition, performance and specifications are rebuilt with IOT fusion products so that they can connect with the current smartphone. This is one of the general-purpose technologies of the 4th industrial revolution, which is spot-lighted with technology that changes the quality and environment of our lives. Along with this, as new technology products combining health care technology increases, various functions are provided to users who need it. Wearable technology is ongoing trend of technology development. It also sells products developed as products in the form of smart watches. At present, various related products are made in various ways, and it is recommended to use the Arduino processor in accordance with the application. In this study, we developed wearable physical activity monitoring system using open source hardware based TinyDuino. TinyDuino is an ultra-compact Arduino compatible board made on the basis of Atmega process Board, and it can be programmed in open source integrated development environment(named Sketch). The physical activity monitoring system of the welfare body can be said to be a great advantage, as a smart u-Healthcare system that can perform daily health management.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.860-870
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• 2016

Continuous monitoring of environmental parameters provides farmers with useful information, which can improve the quality and productivity of crops grown in greenhouses. The objective of this study was to develop a greenhouse environment measurement system using a low-cost microcontroller with open-source software. Greenhouse environment parameters measured were air temperature, relative humidity, and carbon dioxide ($CO_2$) concentration. The ranges of the temperature, relative humidity, and $CO_2$ concentration were -40 to $120^{\circ}C$, 0 to 100%, and 0 to 10,000 ppm, respectively. A $128{\times}64$ graphic LCD display was used for real-time monitoring of the greenhouse environments. An Arduino Uno R3 consisted of a USB interface for communicating with a computer, 6 analog inputs, and 14 digital input/output pins. A temperature/relative humidity sensor was connected to digital pins 2 and 3. A $CO_2$ sensor was connected to digital pins 12 and 13. The LCD was connected to digital pin 1 (TX). The sketches were programmed with the Arduino Software (IDE). A measurement system including the Arduino board, sensors, and accessories was developed (totaling $244). Data for the environmental parameters in a venlo-type greenhouse were obtained using this system without any problems. We expect that the low-cost microcontroller using open-source software can be used for monitoring the environments of plastic greenhouses in Korea.