• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.11-19
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• 2018

Although many researches related to monitoring and automatic measuring devices for early warning system during slope failure have been carried out in Korea and aboard, most of the researches have installed measuring devices on the slope surface, and there are only few researches about warning systems that can detect and warn before slope failure and disaster occurs. In this study, slope failure simulation experiment was performed by attaching sensors to rock bolts, and initial slope behavior characteristics during slope failure were analyzed. Also, the experiment results were compared and reviewed with varied slope conditions, i.e. shotcrete slope and natural slope, and varied material conditions, i.e. GFRP and steel rock bolt. This study can be used as a basic data in development of warning and alarm system for early evacuation through early detection and warning before slope failure occurs in steep slopes and slope failure vulnerable areas.

• Smart Media Journal
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• v.7 no.4
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• pp.44-51
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• 2018

The purpose of this research is to collect atmospheric environmental information at specific altitudes in a range of 0 to 1 km above the surface and to monitor it using drones. The corresponding temperature and humidity were measured with the meteorological factors, and the amounts of fine dust and $CO_2$ were observed by the environmental factors so that they could receive the normal values. Monitoring the status of atmospheric gas emission in specific enterprises, industrial complexes and regions through the measurement is meant to help establish policies to reduce pollution factors. In conventional means previously practiced, exhaust gas detection accompanies a great deal of risks in terms of safety because the surveyor is directly exposed to the source of contamination such as the holes installed in the chimney. However, in our proposed method, the drone can collect information in a wide range under safe circumstances, which can be utilized through wide industrial areas.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.153-172
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• 2018

Overloading of Commercial vehicles have been an important area of transportation as one of the main causes of pavement damage, bridge collapse, severe traffic accident, etc. In this study, we analyzed the effects of overweight prevention by analyzing overweight driving patterns and using weight sensors. First, we analyzed relevant literatures of overweight and surveyed the commercial weight sensors. Then we chose the typical type of overweight vehicles based of overweight enforcement data analysis. MEMs inclinometer weight sensor were installed to 10 test vehicles and data was collected by weight sensors and gps in real time. As a result of gross vehicle weight and axle weight analysis, it was found weight sensor could decrease overweight rate. However, since the number of samples of test vehicles is insufficient to represent the whole commercial vehicle, further studies are deemed possible through the extension test.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.83-90
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• 2018

LoRa (Long Range) is a long-distance, low-power communication technology. Broader range of communication than NFC technology allows communication without having to install multiple APs and reduces the cost of initial infrastructure deployment. MQTT (Message, Queuing, Telemetry, Transport) protocol is also low power and lightweight protocols. It can increase module persistence and reduce maintenance costs when used with LoRa. In this paper, we developed a system for compiling various environmental information in a factory using LoRa and MQTT. Environmental sensor data from long distances can be monitored by the management system and the facilities in each workshop can be controlled. Performance tests have also shown that the use of LoRa and MQTT is effective in terms of long-distance and power consumption.

• Journal of IKEEE
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• v.23 no.3
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• pp.1092-1095
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• 2019

In this paper, we propose the development of an embedded board for construction of smart factory. The proposed embedded board for construction of smart factory consists of main module, ADC module, I/O module. Main module is a main calculating device which includes communication pard that allows interface with external device with using industrial protocol and is ported operating system makes board operating into. ADC module takes part in transferring digital signal has converted from electrical signal to the main module from the external sensor which is installed on the field. I/O module is an input and output module which transfers to the main module about a status, alarm, command signal of field device and it has a function that blocks external noises from field device with isolation circuit into it. In order to evaluate the performance of the proposed embedded board for construction of smart factory, it has been tested by an authorized testing institute. As a result, quantity of interacting protocol was 5, speed of hardware clock synchronization was under 10us and operating time of battery without source power was over 8 hours. It produced the same result as the world's highest level.

• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.26-33
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• 2019

Control moment gyro (CMG) employed as satellite actuators, generates a large torque through the steering of its gimbals. Although each gimbal holds a high-speed rotating wheel, the wheel imbalances induces disturbance and degrades the satellite control quality. Therefore, the disturbances ought to be detected and identified as a precaution against actuator faults. Among the method used in detecting disturbances is the state observers. In this paper, we apply a continuous second order sliding mode observer to detect single disturbances/faults in CMGs. Verification of the algorithm is also done on the hardware satellite simulator where four CMGs are installed.

• Journal of Platform Technology
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• v.9 no.3
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• pp.44-51
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• 2021

In general, golden time refers to the most important time in the initial response to accidents such as saving lives or extinguishing fires. The golden time varies from disaster to disaster, but is aimed at five minutes in terms of fire and first aid. However, for the actual site, the average dispatch time for ambulances is 9 minutes and the average transfer time is 17.6 minutes, which is quite large compared to the golden time. There are various causes for this delay, but the main cause is traffic jams. In order to solve the problem, the government has established emergency car concession obligations and secured golden time to prioritize ambulances in places with the highest accident rate, but it is not a solution in rush hour when traffic is increasing rapidly. Therefore, this paper proposed a deep learning-based emergency vehicle priority signal system using collected sound data by installing sound sensors on traffic lights and conducted an experiment to classify frequency signals that differ depending on the distance of the emergency vehicle.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.74-74
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• 2017

자연하천에서 수자원의 원활하고 안전한 관리에 있어서 오염물의 혼합 거동에 대한 이해는 매우 중요하다. 대부분의 자연하천의 경우 만곡부 및 합류부와 같은 복잡한 지형을 갖고 있으며 이러한 경우 하천의 흐름이 복잡한 형태를 갖게 된다. 특히 수생태계에 많은 영향을 미치는 하폐수 처리장 처리수는 대부분 1차적으로 지류로 방류되어 이후 본류로 지속적으로 유입되게 된다. 이러한 오염물질이 지류로부터 본류로 혼합되는 합류부 구간의 경우 일반적인 1차원 혼합이 아닌 횡방향을 포함하는 2차원적인 혼합 거동에 대한 분석이 필요하다. 본 연구에서는 금호강과 진천천이 좌안으로부터 오염물질이 지속적으로 유입되는 낙동강 중류구간 합류부에서의 혼합 구간의 연구를 위하여 횡분산계수 산정을 위하여 전기전도도(electrical conductivity: EC)를 이용한 농도 추적 실험을 수행하였다. 낙동강 본류에서 정해진 측선을 따라 센서가 설치된 보트를 이용하여 실시간으로 농도, 수리량 데이터를 GPS 위치 데이터와 함께 취득하였다. 또한 실험으로부터 취득한 자료를 바탕으로 2차원 이송-확산 혼합 거동 모델인 CTM-2D 수치모형을 이용하여 모의하였다. 실험 수행 결과, 지류인 금호강과 진천천의 EC 농도가 합류 전 낙동강 본류의 EC 기저농도 보다 더 높은 값을 나타내었다. 지류의 유입으로 인하여 본류 좌안 쪽에서 전기전도도의 값의 상승을 확인할 수 있었으며 하류로 이동할수록 불균등했던 전기전도도의 분포가 횡방향 혼합을 통하여 점점 균등한 분포로 전환되는 것으로 나타났다. 또한 2차원 혼합 거동 분석에 필요한 횡 분산계수 산정을 위해 모멘트법, 해석해를 이용한 추적법, 수치모형을 통한 역산법을 통해 산정하여 결과를 비교하였다. 그 결과 모멘트법의 경우 다른 방법들에 비하여 전반적으로 과소 산정하는 경향을 나타내었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.935-941
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• 2020

People estimation is important to provide IoT services. Most people counting technologies use camera or sensor data. However, the conventional technologies have the disadvantages of invasion of privacy and the need to install extra infrastructure. This paper proposes a method for estimating the number of people using a Wi-Fi AP. We use channel state information of Wi-Fi and analyze that using deep learning technology. It can be achieved by pre-installed Wi-Fi infrastructure that reduce cost for people estimation and privacy infringement. The proposed algorithm uses a k-binding data for pre-processing process and a 1D-CNN learning model. Two APs were installed to analyze the estimation results of six people. The result of the accurate number estimation was 64.8%, but the result of classifying the number of people into classes showed a high result of 84.5%. This algorithm is expected to be applicable to estimate the density of people in a small space.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.5
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• pp.95-108
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• 2011

Smart Grids are intelligent next generating Electric Power System (EPS) that provide environment-friendliness, high-efficiency, and high-trustworthiness by integrating information and communication technology with electric power technology. Smart grids help to supply power more efficiently and safely than past systems by bilaterally exchanging information between the user and power producer. In addition, it alleviates environmental problems by using renewable energy resources. However, smart grids have many cyber security risks because of the bilateral service, the increase of small and medium-sized energy resources, and the installation of multi-sensors or control devices. These cyber risks can cause critical problems within a national grid through even small errors. Therefore, in order to reduce these risks, it is necessary to establish a cyber security strategy and apply it from the developmental stage to the implementation stage. This thesis analyzes and recommends security strategy in order to resolve the security risks. By applying cyber security strategy to a smart grid, it will provide a stepping-stone to creating a safe and dependable smart grid.