• 대한임베디드공학회논문지
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• 제12권6호
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• pp.405-411
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• 2017

As the number of sensors in a ship has increased, studies have been actively conducted to efficiently manage a large amount of data. Sensors in a ship follow the NMEA (National Marine Electronics Association) data format. In particular, NMEA0183 standardized as IEC 61162-1 and NMEA2000 standardized as IEC 61162-3 are widely used. NMEA0183 is a protocol based on serial communication and NMEA2000 is a protocol based on CAN (Controller Area Network) communication. We implemented a gateway that receives data from NMEA0183 sensors and NMEA2000 sensors and then transmits them to the server on TCP/IP network. By using the NMEA2000 0183/2000 gateway to receive the sensor data and manage it through the ship's preventive maintenance system, the sensor data can be utilized efficiently and promptly. This management can reduce crew's daily tasks and reduce the number of accidents.

• 대한임베디드공학회논문지
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• 제13권4호
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• pp.169-178
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• 2018

Currently, various sensors have been used for advanced driver assistance systems. In order to overcome the limitations of individual sensors, sensor fusion has recently attracted the attention in the field of intelligence vehicles. Thus, vision and radar based sensor fusion has become a popular concept. The typical method of sensor fusion involves vision sensor that recognizes targets based on ROIs (Regions Of Interest) generated by radar sensors. Especially, because AVM (Around View Monitor) cameras due to their wide-angle lenses have limitations of detection performance over near distance and around the edges of the angle of view, for high performance of sensor fusion using AVM cameras and radar sensors the exact ROI extraction of the radar sensor is very important. In order to resolve this problem, we proposed a sensor fusion scheme based on commercial radar modules of the vendor Delphi. First, we configured multiple radar data logging systems together with AVM cameras. We also designed radar post-processing algorithms to extract the exact ROIs. Finally, using the developed hardware and software platforms, we verified the post-data processing algorithm under indoor and outdoor environments.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.251-257
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• 1999

Smart structure that contains sensors, which are either embedded in a composite material or attached to a structure, is currently receiving considerable attention. Fiber Bragg grating sensor, one of the optical fiber sensors, has been widely used to sense strain and temperature for smart structures since both parameters change the resonant frequency of the grating. In this paper, according to the various heating and cooling conditions the thermal behavior of unidirectional composite material was monitored by embedding the fiber Bragg grating sensors in the longitudinal and transverse directions of unidirectional composites. The thermal behavior of unidirectional composite material was monitored for various heating and cooling rates and applied pressure. It was found that the thermal behavior was unaffected by pressure variations and heating and cooling rates applied to the composites. The thermal strains were measured by considering the shift in Bragg wavelength that was generated by the thermal expansion of composite specimen. The longitudinal and transverse C.T.E.'s were also obtained from the corresponding temperature-thermal strain curves.

• Composites Research
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• 제18권5호
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• pp.1-8
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• 2005

여러 복합재료 제작기법 중에서 필라멘트 와인딩 제작 기법은 압력탱크, 파이프 등과 같은 실린더 형태의 축대칭 구조물의 제작에 가장 효율적인 방법이다. 또한, 필라멘트 와인딩으로 제작된 복합재료 압력탱크는 운용 중 큰 내압을 받게 되며 복잡한 손상 메커니즘과 파손 모드를 가지고 있다. 그러므로, 필라멘트 와인딩으로 제작된 복합재료 압력탱크는 탱크의 제작 과정과 제작 후 전 과정 동안의 탱크에 대한 건전성 모니터링이 필요하며 이를 위해 탱크의 제작 시부터 탱크 내부의 여러 지점에 센서가 삽입 적용되어야 한다. 여러 센서 중에서 광섬유 센서는 복합재료 내부에 삽입이용이한 센서이며 특히, 광섬유 브래그 격자 센서(fiber Bragg grating Sensors, FBG센서)는 다중화(multiplexing)가 용이한 것을 큰 장점으로 가장 많이 채택되고 있다. 하지만, FBG 센서를 필라멘트 와인딩된 복합재료 압력탱크에 성공적으로 삽입 적용하기 위해서는 극심한 탱크의 삽입 환경에 대한 센서의 삽입 기법의 개발이 선행되어야 한다. 본 연구에서는 필라멘트 와인딩된 복합재료 압력탱크의 제작 시 FBG 센서를 탱크 내부에 다중화하여 삽입적용하기 위한 기법에 대하여 연구하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 컴퓨터소사이어티 추계학술대회논문집
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• pp.61-64
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• 2003

Technological progress in integrated, low-power, CMOS communication devices and sensors makes a rich design space of networked sensors viable. These sensors can be deeply embedded in the physical world and spread throughout sensor network environment like smart dust. So ubiquitous computing will be come true. SmartDust project is the one of ubiquitous computing approach. It produces TinyOS, mote(mica, mica2, rene2, mica2dot, etc.), NesC, TinyDB, etc. We constructs sensor network test bed and tests to approach sensor network and ubiquitous computing.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.160-163
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• 2005

Several sensors are involved in the cor개sion monitoring of concrete structures. This paper deals with the monitoring of concrete structures by embeddable reference sensors. $MnO_2$, MMO and graphite reference sensors are fabricated in the laboratory as suitable as embeddable type into the concrete structures. Sensors are embedded into the mortars and the performance was studied in the absence and presence of chloride ions. The electrochemical stability of the sensors was carried out for the exposure period of one year. Polarisation behaviour and impedance of the sensors in mortar was carried out in three aqueous solutions namely distilled water, 3% NaCl and natural sea water.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.413-416
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• 2004

The tracking antenna system must be always pointed to a satellite for data link among moving vehicles. Especially, for an antenna mounted on a moving vehicle, it needs the stabilized the antenna system. So, software and hardware, signal processing of motion detection sensors, real-time processing of vehicle dynamics, trajectory estimation of satellite, antenna servo mechanism, and tracking algorithm, are unified in the antenna system. The purpose of this paper is to design the embedded tracking antenna control system for satellite communication. The embedded OS(Operating System) based stabilization and tracking algorithm was implemented. The performance of the designed embedded control system was verified by the real satellite communication test.

• 전기학회논문지
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• 제59권9호
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• pp.1692-1698
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• 2010

In this paper we use wireless sensor network and ultrasonic sensors to estimate local position of mobile robots, and to navigate it. Ultra sonic sensor is simple and accurate so it is good to use in local estimation and navigation of mobile robots. But to obtain accurate distance of two sensors they need to face each others as possible as they can. To solve this problem we rotate ultra sonic sensor which is attached to robot in 360 degrees and obtain accurate distance. We can estimate precise position of mobile robot by triangulation using obtained distance information. A mobile robot navigates using embedded encoder and compensates its coordinates by ultrasonic sensors. Results of Experiments show proposed method obtains accurate distance between sensors and coordinates of position of robot. And mobile robots can navigate designated path well.

• Smart Structures and Systems
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• 제19권3호
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• pp.269-277
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• 2017

Recently, there has been significant interest in structural health monitoring for civil engineering applications. In this research, a specially designed tendon, proposed by embedding FBG sensors into the center king cable of a 7-wire strand tendon, was applied for long-term health monitoring of tensile forces on a ground anchor. To make temperature independent sensors, the effective temperature compensation of FBG sensors must be considered. The temperature sensitivity coefficient ${\beta}^{\prime}$ of the FBG sensors embedded tendon was successfully determined to be $2.0{\times}10^{-5}^{\circ}C^{-1}$ through calibrated tests in both a model rock body and a laboratory heat chamber. Furthermore, the obtained result for ${\beta}^{\prime}$ was formally verified through the ground temperature measurement test, expectedly. As a result, the ground temperature measured by a thermometer showed good agreement compared to that measured by the proposed FBG sensor, which was calibrated considering to the temperature sensitivity coefficient ${\beta}^{\prime}$. Finally, four prototype ground anchors including two tension ground anchors and two compression ground anchors made by replacing a tendon with the proposed smart tendon were installed into an actual slope at the Yeosu site. Tensile forces, after temperature compensation was taken into account using the verified temperature sensitivity coefficient ${\beta}^{\prime}$ and ground temperature obtained from the Korean Meteorological Administration (KMA) have been monitored for over one year, and the results were very consistent to those measured from the load cell, interestingly.

• 센서학회지
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• 제16권1호
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• pp.52-61
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• 2007

Networked embedded systems using the smart device and fieldbus technologies are now found in many industrial fields including process automation and automobiles. However the discrepancy between a node's view of current time and the rest of the system can cause many difficulties in the design and implementation of a networked system. To provide a networked system with a global reference time, the problem of clock synchronization has been intensively studied over the decades. However, many of the existing solutions, which are mainly developed for large scale distributed computer systems, cannot be directly applied to embedded systems. This paper presents a fault-tolerant clock synchronization technique that can be used for a low-cost embedded system using a CAN bus. The effectiveness of the proposed method is demonstrated with a set of microcontrollers and DC motor-based actuators.