• 비파괴검사학회지
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• 제28권1호
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• pp.54-58
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• 2008

Time reversal (TR) of body waves in fluids and isotropic solids has been used in many applications including ultrasonic NDE. However, the study of the TR method for anisotropic materials is not well established. In this paper, the full reconstruction of the input signal is investigated for anisotropic media using an analytical formulation, called a modular Gaussian beam (MGB) model. The time reversal operation of this model in the frequency domain is done by taking the complex conjugate of the Gaussian amplitude and phase received at the TR mirror position. A narrowband reference signal having a particular frequency and number of cycles is then multiplied and the whole signal is inverse Fourier transformed. The original input signal is seen to be fully restored by the TR process of MGB model and this model can be more generalized to simulate the spatial and temporal focusing effects due to TR process in anisotropic materials.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.359-367
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• 2004

In this research on-line model for the prediction of the effective strain distribution in strip on finishing mill process is presented. To describe the effective strain distribution in strip, three guide points and a distribution fitting variable are used. On-line models to get these points and fitting variable non-dimensionalization method and least square method were used with FEM simulation results. The model is developed using strip only FEM simulation as reference sets and compared with roll coupled FEM simulation results as perturbed sets. The on-line model to describe effective strain distribution shows good agreement with coupled FEM analysis results.

• 한국콘텐츠학회논문지
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• 제11권12호
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• pp.586-596
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• 2011

현재 IT 분야는 응용을 수행하는 처리 장치가 소형화, 고성능화되고, 센서 기술의 비약적 발달로 인해 다양한 스마트 기능 실현이 가능해지고 있다. 특히, 측정된 사용자 정보를 기반으로 다양한 분석 및 예측을 시도하는 UX(User Experience) 분야는 UI(User Interface)를 중심으로 최근 연구가 활발히 진행되고 있다. 그러나 실세계에서 행동하는 사용자 경험 정보를 효과적으로 분류하고 저장하는 표준화된 형식의 공통 프레임워크에 대한 연구는 아직 미비하다. 본 논문에서는 실세계에서 센싱되어 해석되는 다양한 사용자의 행동정보를 체계적으로 저장 및 참조하기 위한 정보 표현 모델로 AUX(Associative User Experience) 모델과 처리구조를 제안하였다. 이러한 표현모델과 처리체계 분리는 인문적인 사용자 정보의 특성과 기술적인 처리체계의 독립을 통해 AUX 모델 적용 및 처리체계에 전문성과 생산성 및 유연성을 보장한다. AUX 모델은 관심 있는 사용자의 다양한 동작 정보를 확장된 E-TCPN 모델을 이용하여 표현하였다. 그리고 AUX 모델을 응용에서 참조할 수 있도록 XML을 이용한 자료구조로 표현하였다. XML로 표현된 AUX 모델은 응용에서 처리할 수 있는 AUX 정보처리 아키텍처를 설계하고, 이를 적용하여 성능 분석을 수행하기 위해 VOD 서버의 스트리밍 트래픽을 할당하는 MPP 알고리즘을 개선하여, AUX가 처리되는 과정을 나타내었다. 그리고 성능을 분석하기 위해 VOD의 MPP 트래픽 할당 기법에 적용하고, 동작을 시뮬레이션 하였다. AUX 모델을 적용한 MPP 트래픽 할당 알고리즘은 적용하지 않은 알고리즘에 비해 재생 편차가 10.41% 향상되었음을 알 수 있었다. 성능분석 결과는 사용자의 접근 매체 유형과 접근 콘텐츠 정보를 AUX로 변환하여, 동적 트래픽 할당을 위한 MPI, CPI 계산 결과가 스케듈링에 반영되어 재생 성능이 향상 되었음을 알 수 있었다.

• 방사성폐기물학회지
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• 제18권spc호
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• pp.75-87
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• 2020

The Korea Atomic Energy Research Institute (KAERI) has developed geological repository systems for the disposal of high-level wastes and spent nuclear fuels (SNFs) in South Korea. The purpose of the most recently developed system, the improved KAERI Reference Disposal System Plus (KRS⁺), is to dispose of all SNFs in Korea with improved disposal area efficiency. In this paper, a system-level safety assessment model for the KRS⁺ is presented with long-term assessment results. A system-level model is used to evaluate the overall performance of the disposal system rather than simulating a single component. Because a repository site in Korea has yet to be selected, a conceptual model is used to describe the proposed disposal system. Some uncertain parameters are incorporated into the model for the future site selection process. These parameters include options for a fractured pathway in a geosphere, parameters for radionuclide migration, and repository design dimensions. Two types of SNF, PULS7 from a pressurized water reactor and Canada Deuterium Uranium from a heavy water reactor, were selected as a reference inventory considering the future cumulative stock of SNFs in Korea. The highest peak radiological dose to a representative public was estimated to be 8.19×10^-4 mSv·yr^-1, primarily from ¹²⁹I. The proposed KRS⁺ design is expected to have a high safety margin that is on the order of two times lower than the dose limit criterion of 0.1 mSv·yr^-1.

• 정보관리연구
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• 제36권4호
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• pp.155-174
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• 2005

최근 국가적 필요성의 인식 하에 과학기술정보, 특히 연구개발정보의 종합적 수집 관리 및 유통을 위한 국가 과학기술 종합정보 시스템(NTIS)의 개발이 논의되고 있다. 국가 과학기술 종합정보 시스템은 연구개발 프로세스, 연구개발활동, 연구개발정보, 연구개발 데이터 레벨의 구성요소들 간의 유기적 연계를 그 근간으로 한다. 본 논문에서는 국가 과학기술 종합정보 시스템의 개발에 기반이 되는 연구개발정보들 간의 상호연계 모델을 제안한다. 연계를 위해 고려되는 연구개발정보는 연구과제정보, 연구인력정보, 연구성과정보로 연구개발활동에 있어 매우 중요한 정보라 할 수 있다. 제안된 연계 모델을 통해 연구개발정보들 간의 상호 참조 및 탐색이 가능하며, 다양한 관점에서 다양한 형태의 질의를 수행할 수 있다. 연계 모델은 ISO13250 표준인 XML Topic Map을 이용하여 개발되었으며, 예제를 통해 연계 모델의 우수성 및 향후 활용가능성을 살펴보았다.

• 경영정보학연구
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• 제3권1호
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• pp.205-219
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• 2001

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.74.3-74
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• 2001

This paper proposes a nonlinear adaptive controller based on back-stepping method for tracking reference substrate concentration by manipulating dilution rate in a continuous baker´s yeast cultivating process in stirred tank bioreactor. Control law is obtained from Lyapunov control function to ensure asymptotical stability of the system. The Haldane model for the specific growth rate depending on only substrate concentration is used in this paper. Due to the uncertainty of specific growth rate, it has been modified as a function including the unknown parameter with known bounded values. The substrate concentration in the bioreactor and feed line are measured. The deviation from the reference is observed when the external disturbance such as the change of the feed is introduced to the system ...

• Transactions on Control, Automation and Systems Engineering
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• 제4권4호
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• pp.277-282
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• 2002

This paper proposes a nonlinear adaptive controller based on back-stepping method for tracking reference substrate concentration by manipulating dilution rate in a continuous baker's yeast cultivating process in stirred tank bioreactor. Control law is obtained from Lyapunov control function to ensure asymptotical stability of the system. The Haldane model for the specific growth rate depending on only substrate concentration is used in this paper. Due to the uncertainty of specific growth rate, it has been modified as a function including the unknown parameter with known bounded values. The substrate concentration in the bioreactor and feed line are measured. The deviation from the reference is observed when the external disturbance such as the change of the feed is introduced to the system. The effectiveness of the proposed controller is shown through simulation results in continuous system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.4008-4022
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• 2016

This paper tries to extend the conventional conceptual framework of the Internet of Things (IoT) so as to reify an advanced pervasive IoT-community collaboration concept, which is called the process-aware Internet of Things. The extended conceptual framework is embodied as a referential architecture that can be a standardized reference model supporting the conceptual integration of the Internet of Things and the process awareness. The extended referential architecture covers the full range of the architectural details from abstracting the process-aware behavioral semantics to reifying the IoT-process enactments. These extended framework and architecture ought to be the theoretical basis for implementing a process-aware IoT-community computing system supporting process-aware collaborations of Things in pervasive computing environments. In particular, we do point up that the proposed framework of the process-aware Internet of Things is revised from the Internet of Things framework announced in ITU-T SG13³ Y.2060 [26] by integrating the novel concept of process awareness. We strongly believe that the extended conceptual framework and its referential architecture are able to deliver the novel and meaningful insight as a standardized platform for describing and achieving the goals of IoT-communities and societies.

• 한국기계가공학회지
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• 제2권3호
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• pp.41-47
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• 2003

In this study an elevator plant model is made with an electro-hydraulic servo valve and a single rod cylinder. A PID controller, a velocity feedback PID controller and a MRAC controller ate designed. Experimental apparatus including an elevator plant model and these controllers are constructed. In case of experiment, external load which is made with a hydraulic cylinder and a pressure control valve burdens varying load to the elevator plant model being driven. With experiment, the control performances of three proposed control methods are compared.