• International Journal of Internet, Broadcasting and Communication
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• 제10권4호
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• pp.75-82
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• 2018

Efforts to reduce damages from micro dust and harmful gases in life have been led by national or local governments, and information on air quality has been provided along with real-time weather forecast through TV and internet. It is not enough to provide information on the individual indoor space consumed. So in this paper, we propose a IoT-based Real-Time Air Quality Sensing Board Corresponding Fine Particle for Air Quality Management in Buildings. Proposed board is easy to install and can be placed in the right place. In the proposed board, the air quality (level of pollution level) in the indoor space (inside the building) is easy and it is possible to recognize the changed indoor air pollution situation and provide countermeasures. According to the advantages of proposed system, it is possible to provide useful information by linking information about the overall indoor space where at least one representative point is located. In this paper, we compare the performance of the proposed board with the existing air quality measurement equipment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권11호
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• pp.2987-3002
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• 2023

In 2015, the number of senior citizens aged 65 and over in Korea was 6,662,400, accounting for 13.1% of the total population. Along with these social phenomena, risk information related to the elderly is increasing every year. In particular, a fall accident caused by a fall can cause serious injury to an elderly person, so special attention is required. Therefore, in this paper, we implemented a system that monitors fall accidents and informs them in real time to minimize damage caused by falls. To this end, beacon-based indoor location positioning was performed and biometric information based on an integrated module was collected using various sensors. In other words, a multi-functional sensor integration module was designed based on Arduino to collect and monitor user's temperature, heart rate, and motion data in real time. Finally, through the analysis and prediction of measurement signals from the integrated module, damage from fall accidents can be reduced and rapid emergency treatment is possible. Through this, it is possible to reduce the damage caused by a fall accident, and rapid emergency treatment will be possible. In addition, it is expected to lead a new paradigm of safety systems through expansion and application to socially vulnerable groups.

• Smart Structures and Systems
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• 제3권3호
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• pp.321-340
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• 2007

Structural control technologies have attracted great interest from the earthquake engineering community over the last few decades as an effective method of reducing undesired structural responses. Traditional structural control systems employ large quantities of cables to connect structural sensors, actuators, and controllers into one integrated system. To reduce the high-costs associated with labor-intensive installations, wireless communication can serve as an alternative real-time communication link between the nodes of a control system. A prototype wireless structural sensing and control system has been physically implemented and its performance verified in large-scale shake table tests. This paper introduces the design of this prototype system and investigates the feasibility of employing decentralized and partially decentralized control strategies to mitigate the challenge of communication latencies associated with wireless sensor networks. Closed-loop feedback control algorithms are embedded within the wireless sensor prototypes allowing them to serve as controllers in the control system. To validate the embedment of control algorithms, a 3-story half-scale steel structure is employed with magnetorheological (MR) dampers installed on each floor. Both numerical simulation and experimental results show that decentralized control solutions can be very effective in attaining the optimal performance of the wireless control system.

• 대한공간정보학회지
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• 제18권1호
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• pp.111-118
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• 2010

본 논문에서는 도시용수의 효율적인 관리 상 문제점을 파악하고 이를 개선하는 방안을 제시하는데 목적을 두었다. 데이터 모니터링부터 정보화과정 까지를 포함하는 실시간 모니터링 기법을 통해 센싱 데이터를 취득하고 데이터 분석을 통해 용수사용 예측행정에 도움이 되는 일련의 방법론을 제시했다. 또한 센싱 데이터 중 일부 샘플자료를 사용하여 다항식모형을 이용한 추세분석을 실시했다. 연구결과 제시된 실시간 모니터링 기법 및 분석결과는 도시용수 건전성 향상을 위해 중요한 정보제공을 할 것으로 기대된다.

• Structural Engineering and Mechanics
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• 제88권1호
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• pp.83-94
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• 2023

An accurate and highly efficient inverse element labelled iPCB is developed based on the inverse finite element method (iFEM) for real-time shape estimation of plane-curved structures (such as arch bridges) utilizing onboard strain data. This inverse problem, named shape sensing, is vital for the design of smart structures and structural health monitoring (SHM) procedures. The iPCB formulation is defined based on a least-squares variational principle that employs curved Timoshenko beam theory as its baseline. The accurate strain-displacement relationship considering tension-bending coupling is used to establish theoretical and measured section strains. The displacement fields of the isoparametric element iPCB are interpolated utilizing nonuniform rational B-spline (NURBS) basis functions, enabling exact geometric modelling even with a very coarse mesh density. The present formulation is completely free from membrane and shear locking. Numerical validation examples for different curved structures subjected to different loading conditions have been performed and have demonstrated the excellent prediction capability of iPCBs. The present formulation has also been shown to be practical and robust since relatively accurate predictions can be obtained even omitting the shear deformation contributions and considering polluted strain measures. The current element offers a promising tool for real-time shape estimation of plane-curved structures.

• Coupled systems mechanics
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• 제5권2호
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• pp.191-201
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• 2016

Coupled structures are widely seen in civil and mechanical engineering. In coupled structures, monitoring the translational motion of its key components is of great importance. For instance, some coupled arms are equipped with a hydraulic piston to provide the stiffness along the piston axial direction. The piston moves back and forth and a distance sensing system is necessary to make sure that the piston is within its stroke limit. The measured motion data also give us insight into how the coupled structure works and provides information for the design optimization. This paper develops two distance sensing systems for coupled structures. The first system measures distance with ultrasonic sensor. It consists of an ultrasonic sensing module, an Arduino interface board and a control computer. The system is then further upgraded to a three-sensor version, which can measure three different sets of distance data at the same time. The three modules are synchronized by the Arduino interface board as well as the self-developed software. Each ultrasonic sensor transmits high frequency ultrasonic waves from its transmitting unit and evaluates the echo received back by the receiving unit. From the measured time interval between sending the signal and receiving the echo, the distance to an object is determined. The second distance sensing system consists of a wire draw encoder, a data collection board and the control computer. Wire draw encoder is an electromechanical device to monitor linear motion by converting a central shaft rotation into electronic pulses of the encoder. Encoder can measure displacement, velocity and acceleration simultaneously and send the measured data to the control computer via the data acquisition board. From experimental results, it is concluded that both the ultrasonic and the wire draw encoder systems can obtain the linear motion of structures in real-time.

• 한국산학기술학회논문지
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• 제17권5호
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• pp.1-9
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• 2016

본 우리나라 철도 영업 구간중 철도교량은 2012년 기준 약 25%를 차지한다. 이러한 교량 구조들은 시공 직후부터 열차의 충격하중, 태풍, 선박 및 차량 충돌 등 다양한 하중을 받게 된다. 특히 고속 철도 교량의 경우, 열차의 속도로부터 전가되는 매우 큰 충격하중을 받게 되며, 이러한 교량에 가해지는 충격 응답을 분석하는 것은 교량의 안전성 평가에 매우 중요하다. 최근 무선 센서를 이용해 교량의 건전성을 평가하는 연구들이 주목받고 있다. 무선 센서는 가격 및 설치의 용이성으로 인해 교량의 응답계측에 유용하게 적용되고 있다. 하지만 고속철도 교량에서 발생하는 충격 하중은 그 지속시간이 10초 내외로 매우 짧게 발생하므로, 기존 무선 센서의 시스템의 자체 실행 후 시간 지연으로 인해, 이러한 충격하중의 계측은 매우 어렵게 된다. 따라서 본 연구에서는 철도 교량의 충격하중에 의한 구조물의 응답을 계측하기 위한 하드웨어 및 소프트웨어 프레임워크를 제안한다. 구체적으로 1) 초저전력 가속도계를 이용한 구조물의 과도응답 감지 및 평가, 2) 무선 센서 네트워크의 트리거링 후 계측이 시작되는 지연 시간의 단축, 그리고 네트워크의 시간 및 데이터 동기화 기법을 개발하였다. 최종적으로 제안된 프레임 워크에서 소수의 진동 감지 센서 노드들이 상시진동을 계측하며, 열차의 진입으로 인한 진동이 감지될 시, 전체 센서 네트워크의 계측을 시작한다. 시간 지연을 최소화하기 위해 모든 센서는 다른 시작시간을 가지며, 이를 제어하기 위해 후처리 기반 시간 동기화를 한다. 제안된 프레임워크는 실내실험 및 수치해석을 통해 그 효용성을 입증하였다.

• 센서학회지
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• 제27권2호
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• pp.137-141
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• 2018

Detecting the ego-lane of a vehicle (the lane on which the vehicle is currently running) is one of the basic techniques for a smart car. Vision sensing is a widely-used method for the ego-lane detection. Existing studies usually find road lane lines by detecting edge pixels in the image from a vehicle camera, and then connecting the edge pixels using Hough Transform. However, this approach takes rather long processing time, and too many straight lines are often detected resulting in false detections in various road conditions. In this paper, we find the lane lines by scanning only a limited number of horizontal lines within a small image region of interest. The horizontal image line scan replaces the edge detection process of existing methods. Automatic thresholding and spatiotemporal filtering procedures are also proposed in order to make our method reliable. In the experiments using real road images of different conditions, the proposed method resulted in high success rate.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.25-30
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• 1999

This paper covers the development of a highly portable and low cost SPOT image data receiving system. We followed two design approaches. One is the software-based approach by which most of the real-time processing is handled by software. With the complete software-based design, it is simple to add a function for receiving any additional satellite data. Satellite-specific format handlers including error correction, decompression and decryption can easily be accommodated. On the other approach. we used a general hardware platform, IBM-PC and a low cost SCSI RAID (Redundant Away of Independent Disks), and therefore, we can make a low cost system.

• 수산해양기술연구
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• 제41권2호
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• pp.140-146
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• 2005

The aim of our study understands the influence of meteorological factors relating to the formation of the red tide, and monitors the red tide by satellite remote sensing. The meteorological factors have directly influenced on red tide formation. Thus, it was possible to predict and apply to red tide formation from statistical analyses on the realtionships between red tide formation and meteorological factors, and also to realize the near real time monitoring for red tide by satellite remote sensing.