• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3275-3285
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• 2021

A Nuclear Power Plant (NPP) is a complex dynamic system-of-systems with highly nonlinear behaviors. In order to control the plant operation under both normal and abnormal conditions, the different systems in NPPs (e.g., the reactor core components, primary and secondary coolant systems) are usually monitored continuously, resulting in very large amounts of data. This situation makes it possible to integrate relevant qualitative and quantitative knowledge with artificial intelligence techniques to provide faster and more accurate behavior predictions, leading to more rapid decisions, based on actual NPP operation data. Data-driven models (DDM) rely on artificial intelligence to learn autonomously based on patterns in data, and they represent alternatives to physics-based models that typically require significant computational resources and might not fully represent the actual operation conditions of an NPP. In this study, a feed-forward backpropagation artificial neural network (ANN) model was trained to simulate the interaction between the reactor core and the primary and secondary coolant systems in a pressurized water reactor. The transients used for model training included perturbations in reactivity, steam valve coefficient, reactor core inlet temperature, and steam generator inlet temperature. Uncertainties of the plant physical parameters and operating conditions were also incorporated in these transients. Eight training functions were adopted during the training stage to develop the most efficient network. The developed ANN model predictions were subsequently tested successfully considering different new transients. Overall, through prompt prediction of NPP behavior under different transients, the study aims at demonstrating the potential of artificial intelligence to empower rapid emergency response planning and risk mitigation strategies.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.523-526
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• 1998

In an ongoing project at ETRI-CSTL, A debugger for distributed programs that run on a varied collection of machines is being built. To build such debugger, a clientserver model is incorporated. This strategy enables us to provide a unified user interface and isolate debugger core from the user interface. Several debugging servers running on a diverse set of platforms permit the implementation of a distributed debugger for heterogeneous environment, and the single debugging client provides unified debugging concept and graphical user interface over various servers. Also, the precise specification of the interaction protocol between the client and server facilitates client to be paired with a variety of server implementantations. This paper describes the design and implementation of our debugger, concentrating on the system architecture.

• Interaction and multiscale mechanics
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• 제1권4호
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• pp.437-448
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• 2008

This paper examined the stability of high-dense dislocation substructures (HDDSs) associated with martensite laths in High Cr steels supposed to be used for FBR, based on a series of dislocation dynamics (DD) simulations. The DD simulations considered interactions of dislocations with impurity atoms and precipitates which substantially stabilize the structure. For simulating the dissociation processes, a point defect model is developed and implemented into a discrete DD code. Wall structure composed of high dense dislocations with and without small precipitates were artificially constructed in a simulation cell, and the stability/instability conditions of the walls were systematically investigated in the light of experimentally observed coarsening behavior of the precipitates, i.e., stress dependency of the coarsening rate and the effect of external stress. The effect of stress-dependent coarsening of the precipitates together with application of external stress on the subsequent behavior of initially stabilized dislocation structures was examined.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.406-409
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• 2002

The primary insulation system used in an oil-filled transformer is Kraft paper, wood, porcelain and, of course, oil. Modern transformers use paper that is chemically treated to improve its tensile strength properties and resistance to aging caused by immersion in oil. These insulation papers are mainly aged to thermal stress. Over the course of the insulation paper and oil's life it is exposed to high temperatures, oxygen and water. Its interaction with the steel of the tank and core plus the copper and aluminium of the windings will eventually cause the chemical properties of the oil to decay. High temperature have an effect on mechanical strength of cellulous paper using the layer insulation. We made two aging cell in which thermal aging tests of insulation papers and mineral oil are conducted. It is measured dielectric strength, number of acid, moisture, etc. of insulation paper and oil aged in the aging cells.

• 한국레이저가공학회지
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• 제12권2호
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• pp.26-30
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• 2009

Scanning Electron Microscopy (SEM) includes high voltage generator, electron gun, column, secondary electron detector, scan coil system and image grabber. Column includes electron lenses (condenser lens and objective lens). Condenser lens generates fringe field, makes focal length and control spot size. Focal length represents property of lens. Objective lens control focus. Most of the electrons emitted from the filament, are captured by the anode. The portion of the electron current that leaves the gun through the hole in the anode is called the beam current. Electron beam probe is called the focused beam on the specimen. Because of the lens and aperture, the probe current becomes smaller than the beam current. It generate various signals(backscattered electron, secondary electron) in an interaction with the specimen atoms. In this paper, we describe the result of research to develop the core elements for low-resolution SEM.

• 한국가시화정보학회지
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• 제20권2호
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• pp.28-37
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• 2022

Flow characteristics of jet impingement over concave hemispherical surface with effusion cooling holes is relatively more complex than that of a flat surface, so the experimental validation for computational fluid dynamics (CFD) results is important. In this study, experimental results were compared with simulation results obtained by assuming different turbulence models. The vortex was observed in the region between the central jets where the recirculation structure appeared. The different patterns of vorticity distributions were observed for each turbulence models due to different interaction of the injected jet flow. Among them, the transition k-kl-ω model predicted similarly not only the jet potential core region with higher velocity, but also the recirculation region between the central jets. From the validation, it may be helpful to accurately predict heat and mass transfer in jet impingement/effusion hole system.

• 한국전자통신학회논문지
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• 제16권2호
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• pp.379-384
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• 2021

사람들이 인공 지능 분야를 계속 연구하고 제안 한다. 그 때문에 상대적으로 성숙한 인공지능 기술이 일상생활에 더 많이 활용된다. 평소 어디서나 볼 수 있는 생활용품들이 지능화되기 시작하고 있다. 그러나 미러는 생활용품에서 가장 많이 쓰이는 용품 이다. 그 인공 지능 기술을 미러에 적용하는 데 가장 적합 하다. 이 논문의 연구 결과는 라즈베리 pi를 기반으로 설계된 스마트 미러가 날씨, 온도, 인사를 표시하고, 인간-미러 상호작용 기능을 가지고 있다. 본 논문 연구방법은 라즈베리 pi 3B +를 핵심 컨트롤러로 사용하고 Google 어시스턴트를 지능형 제어로 사용한다. 라즈베리 pi의 자체 WiFi를 통해 네트워크에 연결하면 미러가 자동으로 시간, 날씨 및 뉴스 정보 기능을 표시하고 업데이트 할 수 있다. 키워드를 사용하여 Google 어시스턴트를 깨운 다음 미러를 제어하여 음악을 재생하고 시간을 상기시키는 등의 작업을 할 수 있다. 스마트 미러 음성 상호 작용의 기능을 실현한다. 또한 이 연구에 사용 된 하드웨어는 모두 모듈식 어셈블리이고, 나중에 사용자가 직접 조립하는 것이 편리 하며. 저렴한 가격으로 시장 진흥에 적합하다.

• Journal of Electrical Engineering and Technology
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• 제2권2호
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• pp.208-215
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• 2007

The significant drawback of the permanent magnet linear synchronous motor (PMLSM) is force ripples, which are generated by the distortion of the stator flux linkage distributions, cogging forces caused by the interaction of the permanent magnet and the iron core and the end effects. This will deteriorate the performance of the drive system in high precision applications. The PMLSM and its parasitic effects are analyzed and modeled using the complex state-variable approach. To minimize the force ripple and realize the high precision control, the components of force ripples are extracted first and then compensated by injecting the instantaneous current to counteract the force ripples. And this method of the PMLSM system is realized by the field oriented control method. In order to verify the validity of this proposed method, the system simulations are carried out and the results are analyzed. The effectiveness of the proposed force ripples reduction method can be seen according to the comparison between the compensation and non-compensation cases.

• 간호행정학회지
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• 제22권5호
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• pp.437-447
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• 2016

Purpose: The purpose of this study was to conduct a grounded theoretical analysis on the hospital accreditation experience of head nurses in order to understand their behavior on the adaption of this new system. Methods: The participants were 8 head nurses with more than 3 years of experience. The data were collected through in-depth interviews using audiotape recording analyzed by the constant comparative method described in Strauss and Corbin's methodology. Results: There were 113 concepts, 26 subcategories and 12 categories identified through the open coding process. In the axial coding, the following paradigm model was proposed: 1) the causal conditions were 'hardware problem' and 'software problem', 2) the contextual conditions were 'vertical relationship', 'individual preference', and 'family support', 3) the intervening conditions were 'passive conditions' and 'active conditions', 4) the action/interaction strategies were 'leading role' and 'dependent role', 5) the consequences were 'positive acceptance' and 'negative acceptance', 6) the central phenomenon was 'difficult situation' and 7) the core category was 'leading in harmony'. Conclusion: The new system led head nurses having difficulties as the middleman between the hospital administration and general nurses, but they made a continuous effort to overcome and adapt to it through a number of strategies.

• 한국생산제조학회지
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• 제23권1호
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• pp.7-14
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• 2014

The core of the automotive industry's strategy to handle the climate change can be explained as the development and distribution of the vehicles with high fuel efficiencies and low emission. Clean Diesel, hydrogen fuel cell, electric, and especially hybrid power-train vehicles have been actively studied. This paper dynamically analyzes the performance of a hybrid system's five driving modes. The research subject consists of one engine, two electric motors, two simple planetary gears, and one compound planetary gears with five clutches. To define the steady state equation of the system, interaction formulas of five driving modes are introduced with motion variables and torque variables. These formulas are then used to analyze the speeds, torques, and power flows of each mode.