• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제15권7호
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• pp.469-477
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• 2009

제한된 용량의 배터리로 동작해야 하는 모바일 시스템에서는 소프트웨어 설계시 성능뿐만 아니라 전력소모도 고려해야 한다. 따라서 소프트웨어의 실행 중에 전력소모를 정확하게 예측할 수 있으면 전력과 성능을 고려한 효율적인 소프트웨어의 설계가 가능해진다. 본 논문에서는 모바일 프로세서의 전력소모 예측을 위해 정량적으로 프로세서의 동작을 분석하고 모델링 하는 통계적인 분석 방법을 제안한다. 제안된 방식은 다양한 벤치마크 프로그램들을 실행하여 프로세서의 성능 모니터링 이벤트들과 전력소모 데이터를 수집한 후 계층적 클러스터링(hierarchical clustering) 분석 등을 적용하여 서로 중복되지 않으면서 전력소모에 크게 기여하는 대표적인 성능 모니터링 이벤트들을 추출한다. 전력 예측 모델은 선택된 성능 모니터링 이벤트들이 독립변수가 되고 전력소모가 종속변수가 되는 회귀분석(regression analysis)을 수행하여 개발한다. 전력 예측 모델은 Intel XScale 아키텍처 기반의 PXA320 모바일 프로세서에 적용하여 평균 4% 이내의 에러율로 전력소모를 예측할 수 있음을 보인다.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.558-567
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• 2024

Diagnostic support systems are being researched to assist operators in identifying and responding to abnormal events in a nuclear power plant. Most studies to date have considered single abnormal events only, for which it is relatively straightforward to obtain data to train the deep learning model of the diagnostic support system. However, cases in which multiple abnormal events occur must also be considered, for which obtaining training data becomes difficult due to the large number of combinations of possible abnormal events. This study proposes an approach to maintain diagnostic performance for multiple abnormal events by training a deep learning model with data on single abnormal events only. The proposed approach is applied to an existing algorithm that can perform feature selection and multi-label classification. We choose an extremely randomized trees classifier to select dedicated monitoring parameters for target abnormal events. In diagnosing each event occurrence independently, two-channel convolutional neural networks are employed as sub-models. The algorithm was tested in a case study with various scenarios, including single and multiple abnormal events. Results demonstrated that the proposed approach maintained diagnostic performance for 15 single abnormal events and significantly improved performance for 105 multiple abnormal events compared to the base model.

• 전기학회논문지
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• 제67권10호
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• pp.1271-1277
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• 2018

This paper deals with a voltage sag assessment based on a voltage monitoring program. The voltage sag performance at a specific site can be evaluated by analyzing voltage monitoring data recorded for a long time period. Although an assessment based on voltage monitoring is an effective way to understand voltage sag performance at a measurement site, the statistical confidence of voltage sag frequency estimation heavily depends on the length of monitoring period and the number of recorded events. Short monitoring period and insufficient recorded data can not provide a reliable assessment result. This paper proposes a compensation assessment method by combining a computer simulation approach for in case that monitoring period and data are not enough for a valid assessment.

• 정보보호학회논문지
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• 제24권3호
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• pp.507-522
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• 2014

국내 사이버공격 대응 전담조직(CERT)들은 탐지패턴 기반의 보안장비(IDS, TMS 등)를 활용하여 사이버 침해공격에 대한 탐지 대응을 수행하고 있다. 특히, 공공 연구기관의 경우 국가정보원(NIS) 내 국가사이버안전센터(NCSC)를 중심으로 30여개의 부문 보안관제 센터가 구축 운영되고 있으며, 주로 침해위협수집시스템(TMS)을 활용하여 사이버 공격에 대한 탐지 분석 대응을 수행하고 있다. 그러나 현재의 보안관제 체계에서는 대량의 보안이벤트가 보안장비에 의해 발생되고 있을 뿐만 아니라, 보안관제 요원이 보안이벤트에 대한 실제 공격여부를 판단하기 위해서는 추가적인 분석 작업을 수행해야 하므로 보안이벤트 전체에 대한 대응이 현실적으로 불가능한 실정이다. 또한 현재의 보안관제 업무는 보안관제 요원이 보유한 전문지식 및 경험에만 전적으로 의존하고 있기 때문에 특정 보안이벤트에만 분석이 집중되는 업무편중 현상이 발생하며, 이로 인해 기존에 알려지지 않은 새로운 해킹 공격기술에 대한 대응능력이 부족하다. 따라서 본 논문은 실시간 보안관제 및 침해대응 활동의 효율성을 극대화하고 대규모 해킹공격에 대한 조기대응 역량을 강화하기 위해 실제 해킹공격에 대한 실증적 분석에 기반한 대용량 보안이벤트 자동검증 방법을 제안한다.

• Structural Monitoring and Maintenance
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• 제3권1호
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• pp.51-69
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• 2016

Monitoring the performance and estimating the remaining useful life of aging civil infrastructure in the United States has been identified as a major objective in the civil engineering community. Structural health monitoring has emerged as a central tool to fulfill this objective. This paper presents a review of the major structural monitoring programs that have been recently implemented in the United States, focusing on the integrity and performance assessment of large-scale structural systems. Applications where response data from a monitoring program have been used to detect and correct structural deficiencies are highlighted. These applications include (but are not limited to): i) Post-earthquake damage assessment of buildings and bridges; ii) Monitoring of cables vibration in cable-stayed bridges; iii) Evaluation of the effectiveness of technologies for retrofit and seismic protection, such as base isolation systems; and iv) Structural damage assessment of bridges after impact loads resulting from ship collisions. These and many other applications show that a structural health monitoring program is a powerful tool for structural damage and condition assessment, that can be used as part of a comprehensive decision-making process about possible actions that can be undertaken in a large-scale civil infrastructure system after potentially damaging events.

• 한국콘텐츠학회논문지
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• 제11권12호
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• pp.71-77
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• 2011

CEP(Complex Event Processing)는 대규모 정보시스템에서 발생하는 복잡한 이벤트 패턴을 발견하는 기법이다. 게임 사용자가 게임 서버에 접속하여 게임을 수행하는 과정에서 발생하는 이벤트들을 관찰하면서 규칙에 위배되는 행위를 검출하기 위하여 CEP 기법을 사용하는 방법이 제안된 바 있다. 본 연구는 실제 게임서버 DB를 이용하여 선행 연구를 통해 제안된 모니터링 방법에 적용하여 보았다. 이를 통해 CEP 기반의 온라인서비스 감시가 대규모 사용자들이 이용하는 온라인 게임의 부정한 사용자들을 찾아내고 감시하는 것에 효과적임을 관찰하였다.

• Structural Monitoring and Maintenance
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• 제3권3호
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• pp.233-257
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• 2016

This paper provides an overview on development of long-span bridges monitoring in Japan, with emphasis on monitoring strategies, types of monitoring system, and effective utilization of monitoring data. Because of severe environment condition such as high seismic activity and strong wind, bridge monitoring systems in Japan historically put more emphasis on structural evaluation against extreme events. Monitoring data were used to verify design assumptions, update specifications, and facilitate the efficacy of vibration control system. These were among the first objectives of instrumentation of long-span bridges in a framework of monitoring system in Japan. Later, monitoring systems were also utilized to evaluate structural performance under various environment and loading conditions, and to detect the possible structural deterioration over the age of structures. Monitoring systems are also employed as the basis of investigation and decision making for structural repair and/or retrofit when required. More recent interest has been to further extend application of monitoring to facilitate operation and maintenance, through rationalization of risk and asset management by utilizing monitoring data. The paper describes strategies and several examples of monitoring system and lessons learned from structural monitoring of long-span bridges in Japan.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.207-210
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• 2005

Ubiquitous computing is one of the key technology areas in the "Project on Development of Ubiquitous computing and network technology" promoted by the Ministry of Science and Technology as a frontier business of the $21^{st}$ century in Korea, which is based on the new concept merging physical space and computer-based cyber space. With recent advances in Micro Electro Mechanical System (MEMS) technology, low cost and low-power consumption wireless micro sensor nodes have been available. Using these smart sensor nodes, there are many activities to monitor real world, for example, habitat monitoring, earthquake monitoring and so on. In this paper, we introduce web-based real environment monitoring system incorporating wireless sensor nodes. It collects sensing data produced by some wireless sensor nodes and stores them into a database system to analyze. Our environment monitoring system is composed of a networked camera and environmental sensor nodes, which are called Mica2 and developed by University of California at Berkeley. We have modified and ported network protocols over TinyOS and developed a monitoring application program using the MTS310 and MTS420 sensors that are able to observe temperature, relative humidity, light and accelerator. The sensed data can be accessed user-friendly because our environment monitoring system supports web-based user interface. Moreover, in this system, we can setup threshold values so the system supports a function to inform some anomalous events to administrators. Especially, the system shows two useful pre-processed data as a kind of practical uses: a discomfort index and a septicity index. To make both index values, the system restores related data from the database system and calculates them according to each equation relatively. We can do enormous works using wireless sensor technologies, but just environment monitoring. In this paper, we show just one of the plentiful applications using sensor technologies.

• 정보보호학회논문지
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• 제33권6호
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• pp.929-938
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• 2023

모바일 장치에서 사용되는 ARM 프로세서는 하드웨어 기반의 격리 실행 환경인 TrustZone 개념을 도입하여 신뢰 실행 환경인 Secure World와 비신뢰 실행 환경인 Normal World를 구현하였다. 악성 소프트웨어의 종류 중 루트킷은 관리자 권한을 획득하고 자신의 존재를 숨기면서 백도어를 만든다. Secure World에서 동작하는 프로세스는 메모리 접근에 제한이 없고, 격리되어 있어 Secure World에서 루트킷이 실행되었을 때 탐지하기 어렵다. 본 논문에서는 하드웨어 기반의 성능 측정 모니터인 Performance Monitoring Unit을 활용하여 Secure World 루트킷의 이벤트를 측정하고 딥러닝 기반으로 루트킷을 탐지하는 기법을 제시한다.

• Earthquakes and Structures
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• 제8권4호
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• pp.859-887
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• 2015

Structural health monitoring (SHM) has gained in popularity in recent years since it can assess the performance and condition of instrumented structures in real time and provide valuable information to the asset's manager and owner. Operational modal analysis plays an important role in SHM and it involves the determination of natural frequencies, damping ratios and mode shapes of a constructed structure based on measured dynamic data. This paper presents the operational modal analysis and seismic response characterization of the Tsing Ma Suspension Bridge of 2,160 m long subjected to different earthquake events. Three kinds of events, i.e., short-distance, middle-distance and long-distance earthquakes are taken into account. A fast Bayesian modal identification method is used to carry out the operational modal analysis. The modal properties of the bridge are identified and compared by use of the field monitoring data acquired before and after the earthquake for each type of the events. Research emphasis is given on identifying the predominant modes of the seismic responses in the deck during short-distance, middle-distance and long-distance earthquakes, respectively, and characterizing the response pattern of various structural portions (deck, towers, main cables, etc.) under different types of earthquakes. Since the bridge is over 2,000 m long, the seismic wave would arrive at the tower/anchorage basements of the two side spans at different time instants. The behaviors of structural dynamic responses on the Tsing Yi side span and on the Ma Wan side span under each type of the earthquake events are compared. The results obtained from this study would be beneficial to the seismic design of future long-span bridges to be built around Hong Kong (e.g., the Hong Kong-Zhuhai-Macau Bridge).