• Smart Structures and Systems
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• 제29권3호
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• pp.421-431
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• 2022

Concrete slab cracks monitoring of modern high-speed railway is important for safety and reliability of train operation, to prevent catastrophic failure, and to reduce maintenance costs. This paper proposes a curvature filtering improved crack detection method in concrete slabs of high-speed railway via graph-based anomalies calculation. Firstly, large curvature information contained in the images is extracted for the crack identification based on an improved curvature filtering method. Secondly, a graph-based model is developed for the image sub-blocks anomalies calculation where the baseline of the sub-blocks is acquired by crack-free samples. Once the anomaly is large than the acquired baseline, the sub-block is considered as crack-contained block. The experimental results indicate that the proposed method performs better than convolutional neural network method even under different curvature structures and illumination conditions. This work therefore provides a useful tool for concrete slabs crack detection and is broadly applicable to variety of infrastructure systems.

• 한국산학기술학회논문지
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• 제21권10호
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• pp.248-258
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• 2020

본 연구에서는 해외 선진국의 유지관리 체계를 벤치마킹하여 시설물의 생애주기 차원에서 종합적 자산 관리개념을 고려한 유지관리 기술 분류체계를 제안하였다. 이를 위하여 비교사례 연구 기법을 적용하였으며, 국내·외 유지관리 제도, 정의, 기술 분류체계 등을 비교·분석하였다. 비교사례 분석을 위하여 유지관리 비용 집행 비율이 높은 미국, 영국, 일본을 대상 국가로 선정하였고, 해당 국가들의 유지관리 체계를 분석하였다. 다음으로, 국내 유지관리 관련 법에 내포되어있는 인프라 유지관리 기술의 분류 및 정의에 대하여 분석하였다. 그 결과 해외 선진국들은 유지관리 기술의 효과에 따라 유지보수와 개선을 명확하게 분류하고, 예방적 유지관리 활동 중심의 체계를 구성하고 있었다. 반면, 우리나라의 시설물 유지관리 기술은 그 분류 및 정의가 명확하게 구분되지 않고 아직도 사후 대응적 구조 중심으로 이루어져 있어 개선이 필요한 것으로 나타났다. 비교사례연구 결과를 토대로 제안한 분류체계는 유지관리, 유지보수, 성능개선의 개념을 정립하고, 예방적 유지보수와 대응적 유지보수를 명확하게 구분하였다. 결과적으로 제안된 기술 분류체계는 자산관리관점에서 선제적 유지관리 활동과 합리적인 유지관리 예산 분배를 위한 기초연구로서의 활용도가 높을 것으로 기대된다.

• 정보보호학회논문지
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• 제24권1호
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• pp.31-40
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• 2014

국내에서는 공개키 기반구조(PKI, Public Key Infrastructure)를 도입하여, 온라인상에서 안전한 정보 전송과 신원확인을 위해서 인증서 기반의 전자서명 인증체계를 구축하여 서비스를 제공하고 있다. 하지만 인증의 기본이 되는 온라인상의 개인 인감 증명서라고 할 수 있는 인증서는 사용자들이 쉽게 접근하고 복사할 수 있는 위치에 저장되어 있어, PC에 설치된 악성 프로그램이이나 웹 계정 해킹 등과 같은 공격에 의해 유출 될 수 있는 위험이 존재한다. 또한 개인키 패스워드는 키보드보안기능을 무력화 시킨 후 로깅 툴 등에 의해서 노출될 수 있기 때문에 인증서 파일이 유출되는 경우, 금전적인 피해와 불법 인증을 통한 사회적인 범죄가 발생할 수 있는 위험이 존재한다. 본 논문에서는 인증서와 개인키 파일 유출로 인한 피해를 예방하기 위해 해당 키 파일들을 Device에 의존적인 키로 암호화함으로서 안전하게 저장하고, 유출 되더라도 다른 Device에서 사용할 수 없도록 하는 기법을 제안한다.

• International Journal of Internet, Broadcasting and Communication
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• 제12권2호
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• pp.1-7
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• 2020

The secure access the lighting, Heating, ventilation, and air conditioning (HVAC), fire safety, and security control boxes of building facilities is the primary objective of future smart buildings. This paper proposes an authorized user access to the electrical, lighting, fire safety, and security control boxes in the smart building, by using color grid coded optical camera communication (OCC) with face recognition Technologies. The existing CCTV subsystem can be used as the face recognition security subsystem for the proposed approach. At the same time a smart device attached camera can used as an OCC receiver of color grid code for user access authentication data sent by the control boxes to proceed authorization. This proposed approach allows increasing an authorization control reliability and highly secured authentication on accessing building facility infrastructure. The result of color grid code sequence received by the unauthorized person and his face identification allows getting good results in security and gaining effectiveness of accessing building facility infrastructure. The proposed concept uses the encoded user access authentication information through control box monitor and the smart device application which detect and decode the color grid coded informations combinations and then send user through the smart building network to building management system for authentication verification in combination with the facial features that gives a high protection level. The proposed concept is implemented on testbed model and experiment results verified for the secured user authentication in real-time.

• 해양환경안전학회지
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• 제15권2호
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• pp.111-117
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• 2009

국제해사기구(IMO)에서 검토되는 의제들은 갈수록 다양해지고 있으면, 내용도 목적기반선박건조기준(GBS), 선체보호도료의 성능기준개발(PSPC), 선박장거리위치추적제도(LRIT) 등 세부적인 사항까지도 국제적인 표준화를 도모하고 있는 추세이다. 본 논문에서는 IMO 각 위원회의 최근 동향을 살펴보고 이에 대한 한국의 대응 및 활동현황을 조사 분석해 본 결과, A그룹 이사국 지위에 맞는 역할 수행이 아직 미흡하고 정부의 IMO 대응능력을 지속적으로 뒷받침 할 연구지원 인프라가 없는 것으로 나타났다. 이에 한국은 국가차원에서 국제해사동향에 정책적으로 접근할 필요성을 절실히 인지하여야 하며, 국제해사정책을 주도할 수 있는 국내외 인프라 완비가 필요하다고 판단된다.

• 한국정보통신학회논문지
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• 제20권8호
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• pp.1466-1477
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• 2016

공인인증서의 원리 기술인 공개키 기반 구조는 인터넷 환경에서 본인확인, 부인 방지, 문서의 위변조 방지 등의 기능을 제공하는 보안기술이다. 국내 정부기관 및 금융기관들은 인터넷 서비스의 보안 사고 방지를 위해 ActiveX를 이용한 PKI인증시스템을 사용하고 있다. 그러나 ActiveX와 같은 플러그인 기술은 보안에 취약할 뿐만 아니라 특정 브라우저에서만 사용가능하기 때문에 사용자에게 불편함을 초래한다. 이러한 문제점을 해결하기 위해 웹 표준(HTML5) 기반의 인증 기술 연구가 활발하게 진행되고 있다. 최근 국내은행에서 최초로 웹 표준 기반의 PKI인증 기술을 도입하였다. 하지만 채택된 방법은 웹 스토리지의 동일 출처 정책으로 인해 각 사이트마다 인증서를 등록해야 하는 불편함이 있다. 본 논문에서는 동일 출처 정책의 단점을 해결하면서 웹 표준을 준수하는 인증서 기반 통합 인증 프로토콜을 제안하고 안전성을 증명한다.

• 보건교육건강증진학회지
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• 제23권1호
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• pp.143-171
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• 2006

There has been 10 years since the Health Promotion Act was legislated. The government began to establish a health promotion fund on the basis of Health Promotion Act in 1995, and to manage and operate the fund from 1998. It is evaluated that health promotion program have had various outcomes in many aspects. First, there has been growing awareness of the impotance of health promotion through the establishment of Health Plan 2010 and the effort to actualize the Plan. Second, the importance of securing health equity and identifying health determinants have been recognized during the planning process of Health Plan 2010. Third, the health promotion program have mainly focused on improving healthy life style of the population. As a result, desirable health behavior change of the population could be expected from the result of 2005 National Health and Nutrition Survey. Fourth, public health centers began to play a crucial role in implementing health promotion programs, and began to build infrastructure for health promotion programs. Fifth, management efficiency of private health related organizations have been improved. Finally, training for health promotion personnel and their participation in the program could be the foundation for the higher level of outcome achievement from the health promotion programs. Important challenges for future health promotion would be identification of the determinants and risk factors of health, formulating plan of regional health promotion programs, building infrastructure for health promotion, creation of specific action model by public health center, development of health promotion program for the elderly, conducting research for evidence concerning major factors reducing the need for health care through prevention disease activities, and establishment of evaluation and feed back system for health promotion programs.

• Structural Engineering and Mechanics
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• 제37권6호
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• pp.671-684
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• 2011

Deciding on an optimal sensor placement (OSP) is a common problem encountered in many engineering applications and is also a critical issue in the construction and implementation of an effective structural health monitoring (SHM) system. The present study focuses with techniques for selecting optimal sensor locations in a sensor network designed to monitor the health condition of Dalian World Trade Building which is the tallest in the northeast of China. Since the number of degree-of-freedom (DOF) of the building structure is too large, multi-modes should be selected to describe the dynamic behavior of a structural system with sufficient accuracy to allow its health state to be determined effectively. However, it's difficult to accurately distinguish the translational and rotational modes for the flexible structures with closely spaced modes by the modal participation mass ratios. In this paper, a new method of the OSP that computing the mode shape matrix in the weak axis of structure by the simplified multi-DOF system was presented based on the equivalent rigidity parameter identification method. The initial sensor assignment was obtained by the QR-factorization of the structural mode shape matrix. Taking the maximum off-diagonal element of the modal assurance criterion (MAC) matrix as a target function, one more sensor was added each time until the maximum off-diagonal element of the MAC reaches the threshold. Considering the economic factors, the final plan of sensor placement was determined. The numerical example demonstrated the feasibility and effectiveness of the proposed scheme.

• 한국보건교육건강증진학회:학술대회논문집
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• 한국보건교육건강증진학회 2005년도 국민건강증진법 제정 10주년 국제학술대회
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• pp.153-195
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• 2005

There has been 10 years since The Health Promotion Act was legislated. The government began to establish a health promotion fund on the basis of Health Promotion Act in 1995, and to manage and operate the fund from 1998. It is evaluated that health promotion program have had various outcomes in many aspects. First, there has been growing awareness of the impotance of health promotion through the establishment of Health Plan 2010 and the effort to actualize the Plan. Second, the importance of securing health equity and identifying health determinants have been recognized during the planning process of Health Plan 2010. Third, the health promotion program have mainly focused on improving healthy life style of the population. As a result, desirable health behavior change of the population could be expected from the result of 2005 National Health and Nutrition Survey. Fourth, public health centers began to play a crucial role in implementing health promotion programs, and began to build infrastructure for health promotion programs. Fifth, the outcomes of health promotion programs by public health centers and private health organizations have been increasing. Finally, training for health promotion personnel and their participation in the program could be the foundation for the higher level of outcome achievement from the health promotion programs. Important challenges for future health promotion would be identification of the determinants and risk factors of health in Korea, establishment of local health promotion plan, building infrastructure for health promotion, creation of specific action model by public health center, development of diverse health promotion programs and health promotion program for the elderly, conducting research for evidence concerning major factors reducing the need for health care through prevention disease activities, and establishment of evaluation and feed back system for health promotion programs.

• Smart Structures and Systems
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• 제29권1호
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• pp.181-193
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• 2022

Data-driven structural health monitoring (SHM) of civil infrastructure can be used to continuously assess the state of a structure, allowing preemptive safety measures to be carried out. Long-term monitoring of large-scale civil infrastructure often involves data-collection using a network of numerous sensors of various types. Malfunctioning sensors in the network are common, which can disrupt the condition assessment and even lead to false-negative indications of damage. The overwhelming size of the data collected renders manual approaches to ensure data quality intractable. The task of detecting and classifying an anomaly in the raw data is non-trivial. We propose an approach to automate this task, improving upon the previously developed technique of image-based pre-processing on one-dimensional (1D) data by enriching the features of the neural network input data with multiple channels. In particular, feature engineering is employed to convert the measured time histories into a 3-channel image comprised of (i) the time history, (ii) the spectrogram, and (iii) the probability density function representation of the signal. To demonstrate this approach, a CNN model is designed and trained on a dataset consisting of acceleration records of sensors installed on a long-span bridge, with the goal of fault detection and classification. The effect of imbalance in anomaly patterns observed is studied to better account for unseen test cases. The proposed framework achieves high overall accuracy and recall even when tested on an unseen dataset that is much larger than the samples used for training, offering a viable solution for implementation on full-scale structures where limited labeled-training data is available.