• Smart Structures and Systems
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• 제6권9호
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• pp.1079-1105
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• 2010

Railway transport of goods and passengers is effective in terms of energy conservation and travel time savings. Safety and ride quality have become important issues as train speeds have increased. Due to increased speeds, minor damage to railway structures and abnormal interactions between trains and structures have given rise to increasingly serious accidents. Therefore, structural health and operational conditions must be monitored continuously in all service environments. Currently, various health and operation management systems are being developed and these are reducing both maintenance frequency and costs associated with disassembly. In this review, major damage and malfunctions and their locations are first analyzed based on numerous references. Then advanced train health and operation management technologies are classified into wayside detection methods and advanced integrated sensor methods and their operating principle and functions are reviewed and analyzed.

• 대한원격탐사학회지
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• 제20권5호
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• pp.315-327
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• 2004

Nowadays, interests in land cover classification using not only multi-sensor images but also thematic GIS information are increasing. Often, although useful GIS information for the classification is available, the traditional MLE (maximum likelihood estimation techniques) does not allow us to use the information, due to the fact that it cannot handle the GIS data properly. This paper propose two extended MLE algorithms that can integrate both remote sensing images and GIS thematic data for land-cover classification. They include modified MLE and Bayesian predictive likelihood estimation technique (BPLE) techniques that can handle both categorical GIS thematic data and remote sensing images in an integrated manner. The proposed algorithms were evaluated through supervised land-cover classification with Landsat ETM+ images and an existing land-use map in the Gongju area, Korea. As a result, the proposed method showed considerable improvements in classification accuracy, when compared with other multi-spectral classification techniques. The integration of remote sensing images and the land-use map showed that overall accuracy indicated an improvement in classification accuracy of 10.8% when using MLE, and 9.6% for the BPLE. The case study also showed that the proposed algorithms enable the extraction of the area with land-cover change. In conclusion, land cover classification results produced through the integration of various GIS spatial data and multi-spectral images, will be useful to involve complementary data to make more accurate decisions.

• 전기전자학회논문지
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• 제23권1호
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• pp.44-52
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• 2019

본 논문은 라이다 센싱 정보와 RGB-D 카메라 영상 정보를 융합하여 이용하는 교육용 실내 자율주행 로봇 시스템을 구현한다. 이 시스템은 라이다 센싱 정보를 획득하기 위해 기존의 소 채널 라이다 센싱 방식을 이용한다. 또한 소 채널 라이다 센싱 방식의 약점을 보완하기 위해, RGB-D 카메라 깊이 영상과 딥러닝 기반 객체인식 알고리즘을 이용하는 3차원 구조물 인식 방법을 제안하고 이 시스템에 적용한다.

• 자원환경지질
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• 제46권2호
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• pp.105-121
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• 2013

본 연구에서는 원격탐사, 전기비저항탐사, 전기전도도탐사(전자기탐사), 시추공 영상촬영법을 융합하여 효과적인 제방의 안정성 및 누수 평가 방법을 서산 A지구 방조제에 적용하여 제시하였다. Landsat ETM+열적외선 밴드를 사용하여 방조제 부근에서 다른 온도의 해수와 담수가 혼합되는 양상을 통해 누수의 존재, 규모 및 기간을 유추하였다. 전기비저항탐사를 방조제를 따라 실시하여 평균비저항 값 83.197 ${\Omega}$-m이하를 보이는 이상대의 수평적 수직적 분포를 확인하였다. 간조와 만조 시의 전기전도도 값의 분석을 통해 배경치의 영향을 최소화한 수평적 이상대 분포를 확인하였다. 시추공영상촬영을 통해 파쇄대의 수직적 분포양상과 기존 탐사법의 정확도를 확인하였다. 그 결과 전체 제방의 연장 중 41.7%에서 세 수평적 이상대 탐사법의 중첩구간이 확인되었으며, 시추공에서 확인된 수직적 파쇄양상을 고려할 때 누수구간이 제방단면의 중심부를 따라 상당부분 수평적으로 연장이 되어 방대한 양의 누수가 존재할 가능성이 높을 것으로 사료된다. 네 탐사법의 융합적 접근은 각 탐사방법이 가지고 있는 장점을 부각하고 단점을 보완하여 수평적 및 수직적인 누수구간과 기간의 확인 및 판별이 가능하고, 시추공에서 확인된 수직적 파쇄양상의 수평적 연장성을 예측하는데 높은 신뢰도를 보인다 할 수 있다.

• Smart Structures and Systems
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• 제5권4호
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• pp.457-468
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• 2009

A novel approach for integrating active sensing data interrogation algorithms for structural health monitoring (SHM) applications is presented. These algorithms cover Lamb wave propagation, impedance methods, and sensor diagnostics. Contrary to most active-sensing SHM techniques, which utilize only a single signal processing method for damage identification, a suite of signal processing algorithms are employed and grouped into one package to improve the damage detection capability. A MATLAB-based user interface, referred to as HOPS, was created, which allows the analyst to configure the data acquisition system and display the results from each damage identification algorithm for side-by-side comparison. By grouping a suite of algorithms into one package, this study contributes to and enhances the visibility and interpretation of the active-sensing methods related to damage identification. This paper will discuss the detailed descriptions of the damage identification techniques employed in this software and outline future issues to realize the full potential of this software.

• 전기학회논문지
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• 제64권11호
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• pp.1564-1570
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• 2015

This paper intends to suggest a sensing circuit of PWM voltage for a motor emulator operated in the inverter. In the emulation of the motor using a power converter, it is necessary to measure instantaneous voltage at the PWM voltage loaded from the inverter. Using a filter can generate instantaneous voltage, while it is difficult to follow the rapidly changing inverter voltage caused by the propagation delay and signal attenuation. The method of measuring the duty of PWM using FPGA can generate output voltage from the one-cycle delay of PWM, while the cost of hardware is increasing in order to acquire high precision. This paper suggests a PWM voltage sensing circuit using the analogue system that shows high precision, one-cycle delay of PWM and low-cost hardware. The PWM voltage sensing circuit works in the process of integrating input voltage for valid time by comparing levels of three-phase PWM input voltage, and produce the output value integrated at zero vector. As a result of PSIM simulation and the experiment with the produced hardware, it was verified that the suggested circuit in this paper is valid.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2004년도 국내 LBS 기술개발 및 표준화 동향세미나
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• pp.153-158
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• 2004

Nowadays, the demand of the output analyzed from the gridded data has been sharply increased as the remote sensing technologies and GIS related industry have been developed. Therefore, a metadata access system which fits the requirements of the users should be developed for better managing and utilizing gridded data. In this background, this study defined a common application schema through the analysis of the metadata built by numerous institutes based on the draft metadata standards proposed from the study which maily concentrated on establishing the standards of distributing metadata for the gridded data supported by ETRI at 2003. Also, XML based integrated system was developed to access metadata maintained by SaTReC as well as SIMC to facilitate more convenient data access for the grid data users. The results of the pilot system developed from this study can be expected to contribute to build an more efficient and enlarged integrated access system of the metadata for the gridded data.

• Transactions on Electrical and Electronic Materials
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• 제16권1호
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• pp.16-19
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• 2015

A wearable sensing ECG T-shirt for ubiquitous vital signs sensing is proposed. The sensor system consists of a signal processing board and capacitive sensing electrodes which together enable measurement of an electrocardiogram (ECG) on the human chest with minimal discomfort. The capacitive sensing method was employed to prevent direct ECG measurement on the skin and also to provide maximum convenience to the user. Also, low power integrated circuits (ICs) and passive electrodes were employed in this research to reduce the power consumption of the entire system. Small flexible electrodes were placed into cotton pockets and affixed to the interior of a worn tight NIKE Pro combat T-shirt. Appropriate signal conditioning and processing were implemented to remove motion artifacts. The entire system was portable and consumed low power compared to conventional ECG devices. The ECG signal obtained from a 24 yr. old male was comparable to that of an ECG simulator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.761-765
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• 2008

This study presents an effective methodology on integrated monitoring system for a maglev guideway using WDM-based FBG sensors. The measuring quantities include both local and global quantities of the guideway response, such as stains, curvatures, and vertical deflections. The strains are directly measured from multiplexed FBG sensors at various locations of the test bridge followed by curvature calculations based on the plane section assumption. Vertical deflections are then estimated using the Bernoulli beam theory and regression analysis. Frequency contents obtained from the proposed method are compared with those from a conventional accelerometer. Verification tests were conducted on the newly-developed Korean Maglev test track. It has been shown that good agreement between the measured deflection and the estimated deflection is achieved. The difference between the two peak displacements was only 3.5% in maximum and the correlations between data from two sensing systems are overall very good. This confirms that the proposed technique is capable of tracing the dynamic behavior of the maglev guideway with an acceptable accuracy. Furthermore, it is expected that the proposed scheme provides an effective tool for monitoring the behavior of the maglev guideway structures without electro magnetic interference.

• 디지털융복합연구
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• 제15권11호
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• pp.231-243
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• 2017

본 논문은 전기적 감지 방식 바이오센서의 개념을 리뷰하고, 의류 및 텍스트 기반의 바이오센서의 연구 사례를 조사하였다. 생체 신호를 측정 할 수 있는 바이오센서는 생물학적 감지 물질을 이용하여 생물학적 물질의 물리적, 화학적 특성을 감지하는 장치이다. 따라서 바이오센서를 사용하여 생체신호를 측정할 수 있는 웰니스 의류는 U-Health 서비스를 제공하는데 중요한 역할을 한다. 기존 센서와 다르게 바이오센서의 차별화된 특징은 선택적 반응과 생물학적 물질의 결합을 사용한다는 점이다. 이러한 바이오센서 중 전기적 감지 바이오센서는 전기 신호의 처리로 인해 크기가 매우 작아 유비쿼터스 환경을 조성하는데 이용될 수 있다. 따라서 웰니스 의류를 개발하기 위해 소형화가 쉬운 전기적 감지 바이오센서를 연구할 필요가 있다. 본 논문에서는 전기적 감지 바이오센서(전기화학적 방식, 나노와이어/탄소나노튜브 기반 FET 방식)에 대해 자세히 기술하였다. 마지막으로, 이러한 고찰을 통해 향후 웰니스 의류에 적용 가능할 바이오센서의 기술개발 방향을 제언하였다.