• 전기학회논문지P
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• 제54권4호
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• pp.179-184
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• 2005

This paper examines the application of high voltage static var compensator(SVC) with cascade multilevel inverter which employs H-bridge inverter(HBI). A new switching scheme is developed for the SVC system. To improve the unbalanced problem of the DC capacitor voltages, the rotated switching scheme of fundamental frequency is newly used. The optimized fundamental switching pattern with low switching frequency is adapted to be suitable for high application. The selective harmonic elimination method(SHEM) allows to keep the total harmonic distortion(THD) low in the output voltage of multilevel inverter. The SVC system is modeled using the d-q transform which calculates the instantaneous reactive power. This model is used to design a controller and analyze the SVC system. Simulated and experimental results are also presented and discussed to validate the proposed schemes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 학술대회 논문집 전문대학교육위원
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• pp.136-141
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• 2000

This paper proposes the novel control of a static synchronous compensator (STATCOM). This STATCOM system consists of cascade multilevel inverter which employs H-bridge inverter(HBI) The STATCOM system is modeled in the d-q transform matrix. This model is used to design a controller. The selective harmonic elimination method(SHEM) allows to keep the total harmonic distortion (THD) low in the output voltage. The switching method produces the staircase type waveform in cascade multilevel inverter. To balance the DC voltages in HBIs capacitor, the rotated switching scheme is newly proposed in this paper. The proposed control scheme is verified in the simulated results.

• 한국해양공학회지
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• 제18권3호
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• pp.26-31
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• 2004

This paper presents a process planning system that will generate and verify assembly sequences of block assemblies. It consists of a CAD interface system and an assembly sequence planning system. In developing this system, we used an open architecture CAD kernel for the CAD interface system, for visualizing the CAD model and the assembly sequences, and an expert system shell for the assembly sequence planning system. This paper also proposes a framework for the integration of all the steps required to automate the procedures, from design to production. The process planning system is demonstrated by a simple example.

• 제어로봇시스템학회논문지
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• 제7권7호
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• pp.567-573
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• 2001

A real-time HVAC system is proposed which implements real-time control of thermal environment for virtual reality. It consists of a pair of hot and cold loops that serve as thermal reservoirs, and a mixing box to mix hot and cold air streams flowing if from loops. Their flow rates are controlled in real-time to meet a set temperature and flow rate. A cascade control algorithm along with gain scheduling is applied to the system and test results shows that the closed-loop response approached set values within 3 to 4 seconds.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2584-2586
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• 2000

A drum level control is one of the most important control systems in thermal power plant. The control objective of drum level of boiler in thermal power plant is to maintain drum level at constant set-point regardless of disturbance such as main steam flow. The implemented drum level controller is the cascade PI controller. The important factor in drum level controller is the parameters of two PI controllers. The tuning of PI controller parameter is tedious and time-consuming job. In this paper, the relay feedback Ziegler - Nichols tuning method extended to auto-tune cascade PI drum level controller. Finally, the simulation result using boiler model in Power Plant shows the validity of auto-tuned cascade PI controller.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.17-21
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• 2003

This paper presents a CAD interface system that imports CAD model data and exports input information to a CAPP(Compute Aided Process Planning) system to generate a sequence for block assembly operations. In developing this system we use an open architecture CAD kernel, OpenCASCASE. The functions of the system developed are visualization of the product, definition of relations between parts, and generation of relation graph and input file for CAPP. The functions are demonstrated with a simple example.

• 대한기계학회논문집
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• 제16권2호
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• pp.313-324
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• 1992

Two-dimensional Navier-Stokes code has been developed for analysis of turbomachinery blade rows and other internal flows. The Navier-Stokes equations are written in a Cartesian coordinate system, then mapped into a generalized body-fitted coordinate system. All direction of viscous terms are incorporated and turbulent effects are modeled using the Baldwin-Lomax algebraic model. Equation are discretized using finite difference method on the C-type grids and solved using implicit LU-ADI decomposition scheme. Calculations are made at a VKI turbine cascade flow in a transonic wind-tunnel and compared to experimental data. Present numerical scheme is shown to be in good agreement with the previous experimental results and simulates the two-dimensional viscous flow phenomena.

• 전력전자학회논문지
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• 제22권2호
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• pp.118-125
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• 2017

In this paper, we propose a smart transformer for a smart transformer miniature model, which can replace a 60 [Hz] single-phase transformer installed in an electric vehicle. The proposed smart transformer is lighter than a conventional transformer, can control instantaneous voltage, and can be expected to improve power quality through harmonic compensation. The proposed intelligent transformer consists of an incoming part, an AC/DC converter, and a dual active bridge. Only the incoming part and the AC/DC converter are described in this paper. The proposed intelligent transformer has 75 kVA 3.3 kV input and 750 V DC output, which are verified by simulation and experiment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권12호
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• pp.6018-6033
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• 2018

Fires are a common cause of catastrophic personal injuries and devastating property damage. Every year, many fires occur and threaten human lives and property around the world. Providing early important sign for early fire detection, and therefore the detection of smoke is always the first step in fire-alarm systems. In this paper we propose an automatic smoke detection system built on camera surveillance and image processing technologies. The key features used in our algorithm are to detect and track smoke as moving objects and distinguish smoke from non-smoke objects using a convolutional neural network (CNN) model for cascade classification. The results of our experiment, in comparison with those of some earlier studies, show that the proposed algorithm is very effective not only in detecting smoke, but also in reducing false positives.

• Neonatal Medicine
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• 제18권1호
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• pp.1-5
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• 2011

Coagulation involves the regulated sequence of proteolytic activation of a series of proteins to achieve appropriate and timely hemostasis in an injured vessel. In the non-pathological state, the inciting event involves exposure of circulating factor VIIa to extravascularly expressed tissue factor, which brings into motion the series of steps which results in cell based model of coagulation. In the new concepts of coagulation system, initiation, amplification and propagation steps are involved to converse of fibrinogen to fibrin. The precisely synchronized cascade of events is counter-balanced by a system of anticoagulant mechanisms. Developmental hemostasis refers to the age-related changes in the coagulation system that are most marked during neonate and childhood. An understanding of these changes in crucial to the accurate diagnosis of hemostatic abnormalities in neonate and children. This review aims to elucidate the main events within the coagulation cascade as it is currently understood to operate in vivo, and also a short review of the anticoagulants as they relate to this model. Also this paper describes the common pitfalls observed in the clinical data related to the coagulation system in neonate to children.