• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1931-1936
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• 2016

In this paper, we analyzed causes of accidents that recently increased in the illegal and defective LED lamps. They were analyzed by the electrical characteristics calculation and reappearance experiments. The causes of the accidents were analyzed from the circuit affected by the variation of voltage, current and power by harmonics. We drew a conclusion for electrical safety in illegal or degraded LED lamps from the analysis result. The management factors for electrical safety in LED lamps were harmonics, reactive power and power factor. It is possible to secure the electrical safety through monitoring of power factor in failure products and available in smart meters or smart distribution boards.

• International journal of advanced smart convergence
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• v.13 no.3
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• pp.101-108
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• 2024

This paper addresses the implementation of an on-device AI-based metal detection system using a Magneto-Impedance Sensor. Performing calculations on the AI device itself is essential, especially for unmanned aerial vehicles such as drones, where communication capabilities may be limited. Consequently, a system capable of analyzing data directly on the device is required. We propose a lightweight gated recurrent unit (GRU) model that can be operated on a drone. Additionally, we have implemented a real-time detection system on a CPU embedded system. The signals obtained from the Magneto-Impedance Sensor are processed in real-time by a Raspberry Pi 4 Model B. During the experiment, the drone flew freely at an altitude ranging from 1 to 10 meters in an open area where metal objects were placed. A total of 20,000,000 sequences of experimental data were acquired, with the data split into training, validation, and test sets in an 8:1:1 ratio. The results of the experiment demonstrated an accuracy of 94.5% and an inference time of 9.8 milliseconds. This study indicates that the proposed system is potentially applicable to unmanned metal detection drones.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.488-489
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• 2011

This technical reports describes KEPCO's PLC technology and PLC AMI projects. KEPCO has developed PLC and PLC convergence technology. KEPCO's BPL(Broadband over PLC) standard was selected as an IEC International Standard (IEC 12139-1) in 2009. KEPCO conducted a project installing 550,000 smart meters to residential customers finishing in 2010. KEPCO will carry out a PLC-AMI project around country until 2020, as well as many pilot projects to test its PLC convergence technology.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.12
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• pp.101-106
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• 2011

An utilization of electricity usage measured data by region and time through the consumer portal system for building and large consumer are suggested. Electricity usage data by region and time can't be measured by traditional approach. A measured data from smart meters which are installed various regions can be utilized to set up a management of electricity peak demand.

• Smart Structures and Systems
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• v.14 no.3
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• pp.367-376
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• 2014

Ambient vibration techniques are nowadays a very popular tool to assess dynamic properties of buildings. Due to its non destructive character, this method is particularly valuable, especially for health monitoring of historical monuments. The present ambient vibration experiment consists on the evaluation of vibration modes of a Medieval tower. Situated in Soncino (close to Cremona, in the Northern Italian region named Lombardia), the tower of 41.5 meters height has been monitored by seismometers located at different points inside the structure. Spectral ratios of the recorded ambient vibrations clearly identify a fundamental mode at about 1 Hz, with a slight difference in the two horizontal components. A second mode is also evidenced at approx 4-5 Hz, with a moderate degree of uncertainty. The records of a ML 4.4 earthquake, occurred during the monitoring period, confirm the information obtained by microtremor analysis. Daily variations of both 1st and 2nd mode were detected: these variations, of an amount up to 2%, seem to be well related with the temperature.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.2
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• pp.301-307
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• 2021

After the spread of the data collection devices such as smart meters, energy data is increasingly collected in a variety of ways, and its importance continues to grow. However, due to technical or practical limitations, errors such as missing or outliers in the data occur during data collection process. Especially in the case of customer-related data, billing problems may occur, so energy companies are conducting various research to process such data. In addition, efforts are being made to create added value from data, which makes it difficult to provide such services unless reliability of data is guaranteed. In order to solve these challenges, this research analyzes prior research related to bad data processing specifically in the energy field, and propose new missing value processing methods to improve the reliability and field utilization of energy data.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.653-662
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• 2016

Recently, advanced metering infrastructure (AMI) has been recognized as a core technology of smart water grid, and the relevant market is growing constantly. In this study, we developed all-in-one smart water meter of the AMI system, which was installed on the test-bed to verify both effectiveness and field applicability in office building water usage. Developed 15 mm-diameter smart water meter is a magneto-resistive digital meter, and measures flow rate and water quality parameters (temperature, conductivity) simultaneously. As a result of the water usage analysis by installing six smart water meters on various purposes in office building water usage, the water usage in shower room showed the highest values as the 1,870 L/day and 26.6 liter per capita day (LPCD). But, the water usage in laboratory was irregular, depending on the many variables. From the analysis of the water usage based on day of the week, the water usage on Monday showed the highest value, and tended to decrease toward the weekend. According to the PCA results and multivariate statistical approaches, the shower room (Group 3) and 2 floor man's restroom sink (Group 1-3) have been classified as a separate group, and the others did not show a significant difference in both water use and water quality aspects. From the analysis of water usage measured in this study, the leak or water quality accident did not occur. Consequently, all-in-one smart water meter developed in this study can measure flow rate and water quality parameters (temperature, conductivity) simultaneously with effective field applicability in office building water usage.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.139-143
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• 2019

Measurement of flow rate is required in various fields. Water meters are often used at home, and flow meters are used in water and sewage plants, petrochemical industries and so on.. A system is needed to monitor the flow rate in real time and notify immediately when flow rate is abnormal. Recently, with the development of the IoT it is possible to construct such devices at low cost. WeMos can be programmed with Arduino IDE as a mini wifii IoT module. The flow sensor can output a digital pulse proportional to the flow rate. In this paper, we developed the flow monitoring and warning system using WeMos and IoT technology. When the system operates, it calculates the flow rate, sends the value as JSON format to the server, monitors the flow rate as graph from the remote with the smartphone. We also implement the system to promptly send alert message to the smart phone using Pushbullet when the flow rate is abnormal.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.6
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• pp.347-361
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• 2023

Water utilities are making various efforts to reduce water losses from water networks, and an essential part of them is to recognize the moment when a pipe burst occurs during operation quickly. Several physics-based methods and data-driven analysis are applied using real-time flow and pressure data measured through a SCADA system or smart meters, and methodologies based on machining learning are currently widely studied. Water utilities should apply various approaches together to increase pipe burst detection. The most intuitive and explainable water balance method and its procedure were presented in this study, and the applicability and detection performance were evaluated by applying this approach to water supply pipelines. Based on these results, water utilities can establish a mass balance-based pipe burst detection system, give a guideline for installing new flow meters, and set the detection parameters with expected performance. The performance of the water balance analysis method is affected by the water network operation conditions, the characteristics of the installed flow meter, and event data, so there is a limit to the general use of the results in all sites. Therefore, water utilities should accumulate experience by applying the water balance method in more fields.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.199-205
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• 2013

The purpose of this study was to analyze the changes in gait according to four style of bag's carryied method and three different bag's weights. Twenty healthy adults participated in four conditions. The first condition, they wearing a bag on one side shoulder and walked. The second condition, they carried a bag sling across on shoulder and walked. The third condition, they carried a bag on a back using both shoulders and walked. The fourth condition, they hold a bag in their right hand and walked. During all four conditions participants wore a SmartStep insole in their right shoe and had a pressure control device strapped to their right ankle. Each participant walked 10 meters carrying a 2.5 kg, 5 kg and 7.5 kg bag under all four conditions. There were significantly differents in stance phase rate; swing phase rate and walking speed according to bag weight of 2.5 kg, 5 kg, 7.5 kg.