• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.4
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• pp.271-274
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• 2013

Inclinometer sensors are widely applied in many fields. Especially in the field of construction of high-rise buildings also measure the horizontal and vertical help has been applied to monitor. Recent micro electro-mechanical system(MEMS) technology with the development of the many sensors have been developed. In this paper, a MEMS inclinometer is based on a MEMS accelerometer. The sensor can measure the angle of inclination using the relationship between static acceleration and gravity acceleration from an accelerometer. From this principle, inclinometer has been developed that has more accurate. The accuracy is proved by the experiment with laser displacement. Results in the experiment express high-accuracy, stability and economics of MEMS inclinometer. In conclusion, wireless MEMS inclinometer sensor is expected to be applicable in the areas of construction and many other industries with accurate and convenient monitoring system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.3
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• pp.116-124
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• 2011

In this study, a new method to estimate the bridge deflection is developed by using Wireless Tilt Sensor. Most of evaluations of structural integrity, it is very important to measure the geometric profile, which is a major factor representing the global behavior of civil structure, especially bridges. In the past, Because of the lack of appropriate methods to measure the deflection curve of bridges on site, the measurement of deflection had been done restrictly within just a few discrete points along the bridge. Also the measurement point could be limited to locations installed with displacement transducers. So, in this study, the deflection of the structure was measured by wireless tilt sensor instead of LVDT(Linear Variable Differential Transformer). Angle change of tilt sensor shows structural behavior by the change of the resistor values which is presented to voltage. Moreover, the maximum deflection was calculated by changing the deflection angle which was calculated as V(measured voltage) ${\times}$F(factor) to deflection. The experimental tests were carried out to verify the developed deflection estimation techniques. Because the base of tilt measuring is the gravity, uniform measurement is possible independent of a measuring point. Also, measuring values were showed very high accuracy.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.597-600
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• 2010

본 연구에서는 한강 상 교량인 올림픽대교를 대상으로 첨단 무선센서를 구조물 주요 부재에 설치하고 본 센서를 통해 취득되는 데이터를 활용하여 실시간 구조 건전도 모니터링 시스템을 구축하는 것을 목적으로 하였다. 본 시스템은 유비쿼터스 센서 네트워크(USN, Ubiquitous Sensor Network)기술을 적용하여 림픽대교 주요 구조 부재 모니터링을 위한 센서 및 데이터 로깅 시스템으로 구성되어 운영된다. 본 연구에서는 1축 가속도계, 3축가속도계, 온도계, 경사계, 풍향풍속계 5종의 무선 센서를 총 10개 설치하였으며, 센서의 전원은 태양광 자가 전원공급 시스템으로 하였다. 데이터는 시스템 구축완료 후 9월1일부터 9월 7일까지의 일주일간의 데이터를 활용하여, 기존에 설치되어 있던 유선시스템으로부터 취득된 데이터와 비교분석하였으며, 이를 통행 USN 기반의 교량 계측시스템에 대한 실용성을 검증하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.1031-1034
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• 2008

최근 원하는 정보를 수집하기 위한 무선 센서 네트워크(WSN) 사용이 증가하고 있으며, 이때 여러개의 작은 센서들이 배터리의 용량에 한정되어 있기 때문에 가장 우선적으로 고려해야 할 부분은 에너지 효율성이다. Directed Diffusion(DD)은 데이터 중심 기반 라우팅 알고리즘으로 싱크는 모든 센서 노드에게 인터레스트(Interest)를 전송(Flooding)하면 Interest를 받은 노드들은 경사(Gradient)를 만들어서 그 경로들 중 최적화 경로를 강화(Reinforce)한다. 이 경로는 센서 네트워크 전체적으로 볼 때는 에너지를 최소화 하지만, 매 Flooding시 에너지 고갈과 시간 낭비의 문제점이 나타난다. 본 논문에서는 DD의 문제점을 개선하여 싱크가 Interest를 Flooding할 때 마다 여러 번의 Flooding으로 노드의 에너지 고갈과 시간 낭비가 심각해지는 것을 방지하기 위해 중간노드가 Interest를 기억하도록 Middle-Interest Node(MIN)를 두어 데이터를 전달하는 새로운 기법을 제안한다. 본 기법의 성능은 DD와 제안기법인 MIN에 대한 수학적 분석에 기반 하여 측정하였다.

• The KIPS Transactions:PartD
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• v.16D no.2
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• pp.177-184
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• 2009

Environmental monitoring systems are widely developed for analyzing environment and understanding an ecosystem according to the advance of wireless communication and various sensing techniques. To extract useful information, it requires high cost for processing a query, because these systems have to handle huge volume of raw sensor data which is transmitted from a wide area in environmental monitoring applications. Besides, it is also hard to answer an user defined query which requests to check current and near future condition. In this paper, we propose the monitoring system structure for processing a user defined query for environmental monitoring. It also describes the utilization of sensor data filtering and abstraction model. The designed abstraction model which is based on the slope grid in GIS supports fast data access and update. To analyze condition, the extracted data from abstraction model of each sensor type is combined in a query processor. It is useful to provide meaningful information to users.

• Journal of the Korean Geotechnical Society
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• v.34 no.9
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• pp.19-32
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• 2018

In this study, the applicability and practicality of landslides monitoring by using wireless sensor network (WSN) was analysed. WSN system consists of a sensor node for collecting and transmitting data using IEEE 802.14e standard, a gateway for collecting data and transmitting the data to the monitoring server. In the topology of the sensor network, a highly flexible and reliable mesh type was adopted, and three testbeds were chosen in each location of Seoul metropolitan area. Soil moisture sensors, tensiometers, inclinometers, and a rain gauge were installed at each testbed and sensor node to monitor the landslide. For the estimation of the optimal network topology between sensor nodes, the susceptibility assessment of landslides, forest density and viewshed analysis of terrain were conducted. As a result, the network connection works quite well and measured value of the volumetric water content and matric suction simulates well the general trend of the soil water characteristic curve by the laboratory test. As such, it is noted that WSN system, which is the reliable technique, can be applied to the landslide monitoring.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.534-539
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• 2008

This paper is about intelligent hexapod robot for the support walking of the aged person. The robot using various sensors and small camera has various abilities of forward backward walking, turing left or right, control the speed of walking, avoiding the obstacles and detecting risky situation of fire or gas. To let the aged feel soft and safe walking, we used special servo motor and developed hexapod walking mechanism and effective algorithm.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.228-228
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• 2020

과거 무분별하게 획일화되어 개발되었던 하천 개발 사업으로 인해 수질오염과 생태계 훼손으로 하천의 건천화 현상이 발생함에 따라 최근 하천복원 사업이 적극적으로 계획·추진되고 있다. 수생태계의 건강성과 종적 연속성을 회복하기 위한 하천복원사업에 앞서 하천환경의 현상태에 대한 평가는 매우 중요한 부분이다. 유럽과 미국에서는 드론을 활용하여 하천관리 및 재해 피해조사가 활발하게 이루어지고 있었다. 국내의 센서기술과 무선통신 기술의 발전으로 인해 실시간 수집 가능한 정보의 범위가 늘어남에 따라 국내 하천환경 분야에서는 드론을 활용하여 획득된 원격탐사(RS) 자료와 지리정보 데이터베이스를 접목한 하천 공간조사 연구가 증가하고 있는 추세이다. 본 연구에서는 2019년 국토부에서 제시한 하천환경 평가체계에 따라 국내 도시하천중 하천복원사업을 시행하였던 청미천 지역에 대해 현장 조사와 UAV 영상, 항공영상을 활용하여 하천환경평가 결과를 비교하고자 한다. 하천환경평가체계 지침서는 캐나다(2013) 온타리오 하천평가기법을 참조하였으며, 급경사/중경사/완경사로 구분되며 사전조사와 현장조사 야장으로 구성되나 본 연구에서는 물리 평가지표만을 대상으로 하였다. UAV를 이용하여 촬영한 영상을 PIX4D 프로그램을 활용하여 정합한 후 획득된 색체정보를 활용하여 하천환경평가를 실시하였으며, 항공영상은 국토지리정보원의 국토정보플랫폼 국토정보맵에서 다운받은 자료를 활용하였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1324-1331
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• 2008

Recently, landslides have frequently occurred on natural slopes during periods of intense rainfall. With a rapidly increasing population on or near steep terrain in Korea, landslides have become one of the most significant natural hazards. Thus, it is necessary to protect people from landslides and to minimize the damage of houses, roads and other facilities. To accomplish this goal, many landslide prediction methods have been developed in the world. In this study, a simple landslide prediction system that enables people to escape the endangered area is introduced. The system is focused to debris flows which happen frequently during periods of intense rainfall. The system is based on the wireless sensor network (WSN) that is composed of sensor nodes, gateway, and server system. Sensor nodes and gateway are deployed with Microstrain G-Link system. Five wireless sensor nodes and gateway are installed at the man-made slope to detect landslide. It is found that the acceleration data of each sensor node can be obtained via wireless sensor networks. Additionally, thresholds to determine whether the slope will be stable or not are proposed using finite element analysis. It is expected that the landslide prediction system by wireless senor network can provide early warnings when landslides such as debris flow occurs.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.316-321
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• 2007

The casualties due to slope failures such as landslide, rock fall, debris flow etc. are about 24% in total casualties caused by natural disasters for the last 10 years. And these slope failures are focused in the season in which typhoon and torrential rain take place. Not much attention, however, have been put into landslide mitigation research. Meanwhile, USN(Ubiquitous Sensor Network) forms the self-organization network, and transfers the information among sensor nodes that have computing technology ability. Accordingly, USN is embossed a social point technology. The objective of this paper is to develop a prototype system for slope failure monitoring using USN technology. For this we develop module that collects and change slope movement data measured by two tiltermeter and a tension wire, store transferred data in database. Also we develop application program that can easily analyze the data. We apply the prototype system to a test site at KICT for testing and analyzing the system's performance.