• 한국정보통신학회논문지
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• 제26권7호
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• pp.963-971
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• 2022

상수도 관망은 국가 수도 시설의 주요한 구성 요소이지만 대부분이 지중에 매립되어 있어 배관의 노후화 정도 및 누수를 파악하기 어려우므로 유지관리 하기가 매우 어렵다. 본 연구에서는 관망에 설치된 다양한 센서 조합을 가정하여, 데이터 조합에 따른 관로 누수 판별 가능성을 검토하기 위하여 선형회귀분석, 뉴로퍼지 등의 인공지능 알고리즘을 통한 유량과 압력 예측을 실시하여 최적 알고리즘을 도출하였다. 공급압력 예측을 통한 누수판별의 경우 뉴로퍼지 알고리즘이 선형회귀분석에 비하여 우수하였다. 누수유량 예측에서는 뉴로퍼지를 이용한 유량예측이 우선 고려되어야 한다. 다만, 유량을 모사하기 힘든 경우에는 선형 알고리즘을 이용한 공급압력 예측이 이루어져야 할 것으로 사료 된다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.517-520
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• 1999

In this paper, we propose a non-invasive method to estimate blood velocity from the real medical images. To measure the magnitude and direction components associated with the blood velocity, we apply the optical flow analysis algorithm. It is demonstrated that the accuracy of the blood velocity estimate could possibly be increased by segmenting the optical flow region. We call this the Region Optical Flow(ROF) algorithm. We carried out some preliminary experiments using the aorta medical images, and corresponding regional optical flow diagrams are provided.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.69-72
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• 2011

In this paper, we propose a method to track the movement of camera from the video sequences. This method is useful for video analysis and can be applied as pre-processing step in some application such as video stabilizer and marker-less augmented reality. First, we extract the features in each frame using corner point detection. The features in current frame are then compared with the features in the adjacent frames to calculate the optical flow which represents the relative movement of the camera. The optical flow is then analyzed to obtain camera movement parameter. The final step is camera movement estimation and correction to increase the accuracy. The method performance is verified by generating a 3D map of camera movement and embedding 3D object to the video. The demonstrated examples in this paper show that this method has a high accuracy and rarely produce any jitter.

• Interaction and multiscale mechanics
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• 제5권1호
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• pp.27-40
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• 2012

The two-dimensional incompressible flow of a linear viscoelastic fluid we considered in this research has rapidly oscillating initial conditions which contain both the large scale and small scale information. In order to grasp this double-scale phenomenon of the complex flow, a multiscale analysis method is developed based on the mathematical homogenization theory. For the incompressible flow of a linear viscoelastic Maxwell fluid, a well-posed multiscale system, including averaged equations and cell problems, is derived by employing the appropriate multiple scale asymptotic expansions to approximate the velocity, pressure and stress fields. And then, this multiscale system is solved numerically using the pseudospectral algorithm based on a time-splitting semi-implicit influence matrix method. The comparisons between the multiscale solutions and the direct numerical simulations demonstrate that the multiscale model not only captures large scale features accurately, but also reflects kinetic interactions between the large and small scale of the incompressible flow of a linear viscoelastic fluid.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 추계학술발표회논문집(1)
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• pp.403-408
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• 1996

The subchannel analysis was performed to verify the behavior of hot channel characteristics and obtain the information to support the core thermal-hydraulic behavior at post-trip steam line break with low flow condition. During this postulated accident, buoyancy-induced cross flow occurs, and the coupled nuclear and thermal-hydraulic interactions become important. The code predictions with TORC are in good agreement with the test data. Under such conditions, the mass flow increase in the hot channel by buoyancy-induced cross flow depends on the parameter $GR^{*}\;/\;Re^2$, and buoyancy effect becomes more noticeable as $GR^{*}\;/\;Re^2$ increases.

• 한국도서관정보학회지
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• 제25권
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• pp.501-527
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• 1996

This study attempts to provide the foundation that KINITI and industrial su n.0, pporting organizations can be strong information analysis centers if they fortify their information analysis activities. The following conclusions are resulted from the analysis in the state-of-the-art-report covered in national information flow system, service methods and their publications of the information analysis activities provided by the KINITI and industrial su n.0, pporting organizations. First, the KINITI and industrial su n.0, pporting organizations have not be acquiring enough information materials. The services for bibliographic information should guarantee the uses of original documents. Second, the number of organizations providing on-line information services has been increasing, but the provided materials are not sufficiently suited for user's requests. Third, the speedy information provision and efficient information dissemination for the end users in the long distance may be possible through on-line service, but it requires information analysis procedure to select the necessary information in our industrial environment. Forth, the information activities provided by the libraries of industrial su n.0, pporting organizations should be fortified.

• Journal of Mechanical Science and Technology
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• 제19권9호
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• pp.1811-1820
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• 2005

Thermo-acoustic instability of methane/ air flames in an industrial gas-turbine combustor is numerically investigated adopting CFD analysis. The combustor has 37 EV burners through which methane and air are mixed and then injected into the chamber. First, steady fuel! air mixing and flow characteristics established by the burner are investigated by numerical analysis with single burner. And then, based on information on the flow data, the burners are modeled numerically via equivalent swirlers, which facilitates the numerical analysis with the whole combustion system including the chamber and numerous burners. Finally, reactive flow fields within the chamber are investigated numerically by unsteady analysis and thereby, spontaneous instability is simulated. Based on the numerical results, scaling analysis is conducted to find out the instability mechanism in the combustor and the passive control method to suppress the instability is proposed and verified numerically.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권12호
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• pp.3315-3337
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• 2012

Crowded scenes analysis is a challenging topic in computer vision field. How to detect diverse motion patterns in crowded scenarios from videos is the critical yet hard part of this problem. In this paper, we propose a novel approach to mining motion patterns by utilizing motion information during both long-term period and short interval simultaneously. To capture long-term motions effectively, we introduce Motion History Image (MHI) representation to access to the global perspective about the crowd motion. The combination of MHI and optical flow, which is used to get instant motion information, gives rise to discriminative spatial-temporal motion features. Benefitting from the robustness and efficiency of the novel motion representation, the following motion pattern mining is implemented in a completely unsupervised way. The motion vectors are clustered hierarchically through automatic hierarchical clustering algorithm building on the basis of graphic model. This method overcomes the instability of optical flow in dealing with time continuity in crowded scenes. The results of clustering reveal the situations of motion pattern distribution in current crowded videos. To validate the performance of the proposed approach, we conduct experimental evaluations on some challenging videos including vehicles and pedestrians. The reliable detection results demonstrate the effectiveness of our approach.

• 디지털융복합연구
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• 제19권1호
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• pp.389-399
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• 2021

본 논문의 연구배경은 플로우 이론을 적용한 u-융합정보시스템이 관광객의 만족도 측정이 부족하기 때문에 연구를 시작하게 되었다. 본 연구의 목적 및 연구 방법은 다음과 같다. 첫째는 플로우 관계정보 표시형식 알고리즘 제안이다. 둘째는 이 알고리즘과 플로우 이론을 접목시켜 콘텐츠 정보품질과 관광객의 성격 유형에 따라 패턴 알고리즘을 생성한 것이다. 본 연구의 기대효과는 플로우 관계정보 표시형식과 관광객의 성격 유형에 따라 패턴 알고리즘을 생성함으로서 u-융합정보시스템의 성공요인을 도출한 것이다. 본 논문의 한계성은 한 지역을 한정적으로 하였으며 데이터의 부족과 소규모 지역으로 객관성이 떨어진다. 추후, 다른 관광지에 제시하는 방법 적용 후, 분석을 통해 효용성을 평가할 필요가 있다. 향후 과제는 전문가 집단의 데이터 보완이 필요하고 여러 지역의 객관성이 보완되어야 할 것이다.

• 한국지리정보학회지
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• 제9권3호
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• pp.14-24
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• 2006

국내에서 이루어지고 있는 부분적인 교통량분석 장비에는 여러 문제점과 한계성을 가지고 있다. 또한, 교통량분석 장비를 통하여 획득한 기존의 교통량 정보는 실시간 제공이 되지 못하고, 도심지의 경우 교통량 밀도분석과 시계열 분석이 어려워 적절한 도로용량 파악의 신뢰성 확보에 한계가 있고, 교통소통 제어관련 정보를 제공하지 못하는 등 도로정책 수립에 활용하기 어려운 실정이다. 따라서 실시간 교통량조사를 통한 정확한 도로소통정보와 후처리 통계분석에 의한 도로소통정보를 통해 정확하고 신속한 교통 및 도로소통정책수립이 필요하다. 본 연구에서는 차량위치정보를 교통정보화하여 교통관제센터로 교통정보를 전송할 수 있는 인공위성측량 기술기반의 차량용 교통정보수집시스템을 개발하였다. 또한, 전송된 교통정보를 관리 분석하고 처리된 도로소통정보를 실시간으로 웹상에 제공해줄 수 있는 웹 지리정보체계 기술기반의 교통관제시스템을 개발하였다.