• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.32 no.6
• /
• pp.401-408
• /
• 2019

The objective of this study is to develop a new type of buried sensor module that can directly assess pre-stressed concrete by measuring strain using a hetero-core optical fiber sensor. In this regard, experiments were conducted to evaluate the performance of the sensor using an exposure sensor module. Based on the experimental results, when the values of the displacement control velocity were 0.12 mm/min and 1.80 mm/min, the corresponding delays in the measurement were 52.1 s and 2.6 s respectively, which indicated that the maximum delay between the two measurements was a factor of 19. Due to the measurement delay phenomena, the sensor module used in the experiments cannot be employed to check the real-time state of the structure. Thus, additional experiments were needed to develop a new sensor module that can measure the real-time state of the structure. To investigate the cause of the measurement delay phenomena, three experiments were conducted. It was confirmed that measurement delay is mainly attributed to frictional resistance. The measurement delay phenomena were not observed in the experiments using the friction-removed device.

• 한국HCI학회:학술대회논문집
• /
• 2007.02a
• /
• pp.328-333
• /
• 2007

RFID와 sensor network의 두 기반 기술은 독특한 물리적 특정을 가지며 상호 보완적인 관계를 가지고 있다. 이러한 관계는 창고 안 물품의 상태파악과 입출 재고를 관리하는 형태로 응용된다. 창고 내 물품 보관 단위인 파렛트(Pallet) 에 RFID 태그를 부착하여 입/출고시의 물품을 식별한다. 그리고 Zigbee 무선 통신기능을 가진 센서 모듈에 의해 물품의 환경 상태 정보를 파악한다. 이후 현장 관리자나 소비자들은 이동형 단말장치를 통해 현장에서 다양한 USN 상의 정보들과 상호작용 한다. 이 과정에서 이동형 단말장치를 통한 RFID tag 정보와 센서 노드의 접근이 공중파 상에 노출 된다. 이러한 센서 노드 접근을 보호하기 위해 추가적인 칩 설계 등의 비용 지불로 기밀 노출에 대처할 수 있다. 이에 대한 대안으로 인프라형태로 놓여진 RFID tag와 단말장치에 탑재될 RFID 리더를 활용해 더 적은 비용으로 보안 서비스를 받고자 한다. 그래서 유비쿼터스 환경에서 센서 노드에 대한 접근을 제어하기 위해 RFID tag를 지역키(local key) 처럼 사용한다. 또한 이 과정에 보안이 적용된 프로토콜을 설계 하는 것이 본 논문의 주된 목표이다.

• Proceedings of the KAIS Fall Conference
• /
• 2012.05b
• /
• pp.812-816
• /
• 2012

본 논문은 산사태 감지 및 붕괴예측을 위한 현장에 USN(Ubiquitous Sensor Network)을 적용한 실시간 모니터링 시스템 모델을 개발하였다. 이 시스템의 성능을 검증하기 위해 USN기반의 상시모니터링시스템모델을 제작하고 실험적 평가를 수행하였다. 성능평가는 지표변위 센서모듈 동작특성 실험적 평가, USN은 Data 수집 전송 효율성 실험적 평가, 개발한 상시감시모니터링 프로그램 동작성능 실험적 평가 등을 수행하였다. 성능평가 결과 지표변위 측정센서모듈은 변위각도에 일치성을 확인하고, USN은 지표변위 센서모듈로부터 측정된 Data를 상시모니터링시스템에 오류 없이 전송되는지를 확인하였으며, 개발한 상시모니터링 프로그램 동작기능은 실시간 모니터링 그래프, 임계동작 알고리즘, 위험성 통보 문자서비스(SMS)기능, 알람서비스기능, 현장 감시카메라 등 동작기능의 우수성을 실험으로 증명하였다. 따라서 본 연구에서 개발된 산사태 감지 예측을 위한 USN기반 실시간 모니터링 시스템 모델은 산사태위험성노출 지역에 원격 실시간 모니터링 시스템으로 널리 사용될 것으로 사료된다.

• Journal of the Society of Disaster Information
• /
• v.17 no.4
• /
• pp.890-896
• /
• 2021

Purpose: The called Aero System is important to find the well detected place in the livingroom or bedroom so, it needs to the confirmation through the Fire Dynamics Simulation Method: A fire simulation of a residential space of 59 m² was performed, and in order to find the point where the fire environment was exposed quickly, measuring points were installed at 0.6 m and 1.5 m in height for each bedroom and living room, and the point where the fire was quickly detected was confirmed. Result: It was confirmed that the temperature and carbon monoxide sensor set at a point of 1.5 m was quickly detected at the reference value. Conclusion: The Fire detection would be relatively quick if the product in which the fire extinguishing module and the AQI module were separated was installed on the wall.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.11
• /
• pp.99-106
• /
• 2016

When radon is staying at alveoli and bronchial tubes, the collapse of radon creates progeny nuclides (alpha ray, beta ray, gamma ray, etc.). They emit radiation causing a mutation in the chromosome of the cell, resulting in lung cancer. In other words, the main cause of lung cancer is radiation emitting as the result of radon collapse rather than radon gas. The 82% of radiation exposed to people is the natural radiation. Most of the natural radiation is radon. If we properly control the concentration of radon indoors, the probability of occurrence of lung cancer could be decreases to be 70%. Until now, to measure the indoor radon concentration, imported radon sensors are needed. So, DB construction of indoor radon emission and popular radon measuring apparatus should be developed. In this paper, we propose the radon detecting method using PIN photodiode. Also, we confirmed the PIN photodiode could be used as radon sensor module through some experimental studies.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.13 no.1
• /
• pp.27-34
• /
• 2020

Human access is restricted to environment where radiation sources are used, however observation equipment should be radiation-resistant as it is exposed. Therefore, if tungsten with the highest specific gravity and melting point and the lowest lead were selected to reduce the dose to the Cobalt 60 radiation source to 1/8, Tu had a volume of 432.6cm3, a thickness of 2.4cm, and Pb had a volume of 961cm3,, a thickness of 3.6cm. By applying this method, produced a radiation resistant CMOS camera with a camera module using a CMOS Image sensor and a radiation shielding structured housing. As a result of applying the head detachable 2M AHD camera (No. ①) that survived the experiment to select the optimal shielding thickness, when shielding the associated equipment such as cameras, adapters, etc. is achieved, it was confirmed that the design of the structure is appropriate by operating well at doses higher than 1.88×106rad. Therefore, it is expected to secure the camera technology and business feasibility that can be applied to high radiation environments.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.26 no.2
• /
• pp.28-36
• /
• 2022

As port structures are exposed to various extreme external loads such as wind (typhoons), sea waves, or collision with ships; it is important to evaluate the structural safety periodically. To monitor the port structure, especially the rubber fender, a fender segmentation system using a vision sensor and deep learning method has been proposed in this study. For fender segmentation, a new deep learning network that improves the encoder-decoder framework with the receptive field block convolution module inspired by the eccentric function of the human visual system into the DenseNet format has been proposed. In order to train the network, various fender images such as BP, V, cell, cylindrical, and tire-types have been collected, and the images are augmented by applying four augmentation methods such as elastic distortion, horizontal flip, color jitter, and affine transforms. The proposed algorithm has been trained and verified with the collected various types of fender images, and the performance results showed that the system precisely segmented in real time with high IoU rate (84%) and F1 score (90%) in comparison with the conventional segmentation model, VGG16 with U-net. The trained network has been applied to the real images taken at one port in Republic of Korea, and found that the fenders are segmented with high accuracy even with a small dataset.

• Journal of the Institute of Convergence Signal Processing
• /
• v.10 no.3
• /
• pp.207-213
• /
• 2009

The quality of tap water on the whole water-supply system, from a large filtration plant to a private faucet, has to be guaranteed the standards of drinking water. At this point in time, however, the supply process of the tap water has not been monitored and managed scientifically. The piped water, especially the most small-scale reservoirs(underground or overhead type) are always exposed to various contaminations and impurities. Recently monitoring systems of water-quality were spread on some large filtration plants or distributing reservoirs. In particular, the water quality monitoring method using the internet is adopted into some local government whose inhabitants can check up the water quality anytime and anywhere. The construction of this system that has to apply a large scale needs, and has a limitation on the small water-supply system, such as apartments, public facilities and small-scale underground or overhead reservoirs. In this work, we suggest the integration system of individual water-quality sensor modules that have a low price. By using the developed integration system and online monitoring program operated on the internet, the system managers of reservoirs can monitor and manage water-quality characteristic values of drinking water in online. Since the proposed system was modularized, the system can be applied easily into various reservoirs with a low cost and regardless of its scale, small or large.