• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.209-213
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• 1997

This paper deals with sensing ability of $2^{nd}$ smart sensor that has a sensing ability of distinguish materials. We have developed new signal processing method that have distinguish different materials. We made the $2^{nd}$ smart sensor for experiment. The second type of smart sensor is HH type. We have developed a new signal processing method that can distinguish among different materials. The estimation method (RSAIIn dex) is developed for $2^{nd}$ smart sensor(HH smart sensor). Experiment and analysis are executed for estimation the new method. We estimated sensing ability of $2^{nd}$ smart sensor with RsA, method. Sensing Ability of the $2^{nd}$ smart sensor were evaluated relatively through a new RsAl method. According to frequency changing, influences of the $2^{nd}$ smart sensor are evaluated through a new recognition index RSAI. Applications of this method are for finding abnormal conditions of objects (automanufacturing), feeling of objects (medical product), robotics, safety diagnosis of structure, etc.

• 농촌계획
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• 제25권2호
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• pp.15-21
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• 2019

The agricultural environment is changing and becoming more advanced due to the influence of the 4th Industrial Revolution. From the basic plan of Rural Informatics to the current level of 2nd generation smart farms aimed at improving productivity using Big data, cloud network and more IoT technology. We are continuing to provide support and research and development. However, many problems remain to be solved in order to supply and settle smart farms in Korea. The purpose of this study is to provide a method of collecting and sharing data on farming environment and to help improve the income and productivity of farmers based on collected data. In the case of hog farm, the multiple sensors for environmental data like temperature, humidity and gases and the network environment for connecting the internet were established. The environment sensor was made using the ESP8266 Node MCU board as micro-controller, DHT22 sensor for temperature and humidity, and MQ series sensors for various gases in the hog pens. The network sensor was applied experimentally for one month and the environmental data of the hog farm was stored on a web database. This study is expected to raise the importance of collecting and managing the agricultural and environmental data, for the next generation farmers to understand the smart farm more easily and to try it by themselves.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.461-480
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• 2010

This paper analyses the data collected from the $2^{nd}$ Jindo Bridge, a cable-stayed bridge in Korea that is a structural health monitoring (SHM) international test bed for advanced wireless smart sensors network (WSSN) technology. The SHM system consists of a total of 70 wireless smart sensor nodes deployed underneath of the deck, on the pylons, and on the cables to capture the vibration of the bridge excited by traffic and environmental loadings. Analysis of the data is performed in both the time and frequency domains. Modal properties of the bridge are identified using the frequency domain decomposition and the stochastic subspace identification methods based on the output-only measurements, and the results are compared with those obtained from a detailed finite element model. Tension forces for the 10 instrumented stay cables are also estimated from the ambient acceleration data and compared both with those from the initial design and with those obtained during two previous regular inspections. The results of the data analyses demonstrate that the WSSN-based SHM system performs effectively for this cable-stayed bridge, giving direct access to the physical status of the bridge.

• 전기전자학회논문지
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• 제23권2호
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• pp.636-641
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• 2019

저항형 센서 브리지들을 인터페이싱 하기 위한 간단한 저항 편차-시간 주기 변환기를 제안한다. 제안된 변환기는 두 개의 2세대 전류 컨베이어(current conveyor II: CCII)로 구성된다. 제안된 변환기는 연산 증폭기 또는 연산 트랜스컨덕턴스 증폭기(OTA)로 구성되는 기존의 변환기들보다 회로 구성이 간단하다는 장점을 가진다. 제안된 변환기를 AD844로 구현한 CCII를 이용하여 PSPICE 시뮬레이션을 진행하였다. 실험 결과는, 변환기가 $100{\sim}500{\Omega}$의 저항 편차 범위에 걸쳐서 $0.01934ms/{\Omega}$의 변환 감도를 가지며 선형 오차는 ${\pm}0.002%$ 이내라는 것을 보여준다.

• 센서학회지
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• 제21권4호
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• pp.241-248
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• 2012

Recently healthcare industry such as pharmaceutical, medical device and healthcare service technology is growing significantly. Mobile healthcare has attracted big attention due to IT convergence technology. Paradigm of healthcare has been changed from the 1st generation(communicable disease prevention) and the 2nd generation(treatment of disease due to extended life expectancy) to the 3rd generation(extended life expectancy due to prevention and control). In our study, we suggest the 3rd generation mobile healthcare system using Bluetooth based wearable ECG monitoring system and smart phone technology. The mobile healthcare system consists of wearable shirts with Bluetooth communication module, ECG sensor, battery, and mobile phone. The ECG data is obtained by a miniaturized sensor and the data is transferred to a mobile phone using Bluetooth communication. Then, user can monitor his/her own ECG signal on an application using Android in mobile phone. The Bluetooth communication device is used due to highly reliable data transmission property and the Bluetooth chip is embedded in every mobile phone. The wearable shirts with chest belt of Bluetooth ECG module is designed with a focus on convenience in the daily life of a wearer. The ECG signal evaluation software in Android based mobile phone is developed for the health check and the ECG signal variation is tested according to the activities of the wearer such as walking, climbing stairs, stand up and sit down, and so on.

• 한국ITS학회 논문지
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• 제23권4호
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• pp.37-53
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• 2024

본 연구는 자전거도로에서의 사고 예방 및 위험요소 관리를 위해 이동형 IoT 센서 장비 운용을 위한 자전거도로 위험 감지요소 선정 및 서비스 적용방안을 제시하였다. 전문가 심층조사를 통해 12개의 자전거도로 위험 감지요소를 도출하였고, 도로·교통 전문가 30명을 대상으로 Fuzzy AHP 기반의 중요도 분석을 수행하였다. 그 결과, 시인성이 낮으나 사고 위험성이 높은 포장상태 손상(전체 1순위), 환경적 장애요소(2순위)가 최상위권에 선정되었다. 중상위권으로는 단절노선 발생(4순위), 인공적 장애요소(5순위), 유효 폭(6순위), 배수 불량(7순위) 등 시설관리 요소들이 선정되었다. 노면표시 손실(11순위), 여유공간 폭(12순위)과 같이 직접적인 사고유발 요인이 아닌 요소들은 최하위권에 선정되었다. 이를 토대로 자전거도로 위험 감지 서비스 적용방안 및 실시간성에 따른 서비스 운영전략을 함께 제시하였다. 향후 자전거도로 유형별 분석, 서비스 실증 및 시범운영 등 후속연구가 활발히 진행되어, 국민들이 안전하게 이용할 수 있는 자전거도로 운영 및 관리가 이루어지길 기대한다.

• Smart Structures and Systems
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• 제31권1호
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• pp.1-11
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• 2023

Assessment of the compressive strength of concrete plays a major role during formwork removal and in the prestressing process. In concrete, temperature changes occur due to hydration which is an influencing factor that decides the compressive strength of concrete. Many methods are available to find the compressive strength of concrete, but the maturity method has the advantage of prognosticating strength without destruction. The temperature-time factor is found using a LM35 temperature sensor through the IoT technique. An experimental investigation was carried out with 56 concrete cubes, where 35 cubes were for obtaining the compressive strength of concrete using a universal testing machine while 21 concrete cubes monitored concrete's temperature by embedding a temperature sensor in each grade of M25, M30, M35, and M40 concrete. The mathematical prediction model equation was developed based on the temperature-time factor during the early age compressive strength on the 1^st, 2^nd, 3^rd and 7^th days in the M25, M30, M35, and M40 grades of concrete with their temperature. The 14^th, 21^st and 28^th day's compressive strength was predicted with the mathematical predicted equation and compared with conventional results which fall within a 2% difference. The compressive strength of concrete at any desired age (day) before reaching 28 days results in the discovery of the prediction coefficient. Comparative analysis of the results found by the predicted mathematical model show that, it was very close to the results of the conventional method.

• 전자공학회논문지
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• 제49권11호
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• pp.118-131
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• 2012

기존 전자발찌 시스템은 GPS 위성 및 휴대폰 기지국 통신을 통해 성범죄자의 위치를 추적하고 재범을 방지하는 장치이다. 하지만 GPS 위성통신 방식은 위성 신호 수신이 어려운 도심 건물의 실내나 지하철에서는 제대로 작동하지 않는다. 이러한 경우 휴대폰 기지국 통신을 통해 위치추적을 할 수 있다. 그러나 휴대폰 기지국은 설치범위가 수백 미터 간격으로 넓기 때문에, 위치추적을 할 경우 오차범위가 최대 2 km일 만큼 정확도가 떨어진다. 만약 도심의 5층 건물에서 유치원이 2층에 위치해 있고 커피숍과 성범죄자가 3층에 위치해 있다면, 기존 전자발찌는 건물 내부로 인해 GPS 위성통신으로 위치추적이 안되고 휴대폰 기지국 통신으로도 정확한 층에 대한 위치인식이 안 된다. 전자발찌는 위치인식 기반의 시스템으로 이러한 현상은 커다란 문제가 된다. 따라서 본 논문은 이런 위치인식 불가의 극한환경에서 USN을 이용하여 성범죄자들을 감시할 수 있는 스마트 전자발찌 시스템을 제안한다.