• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 동계연구발표회 논문개요집
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• pp.17-17
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• 2002

The magnetic effects connected to finite-size of the particles become dominant at transition of particles in region several nanometers and less [1]. At reduction of atom numbers in magnetic cluster (tens or hundreds atoms), along the classical features, essential appear the quantum phenomena resulting in spin transformation of magnetic structure, both with reduction of the size and at applying of an external magnetic field. (omitted)

• 대한전기학회논문지
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• 제38권6호
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• pp.431-440
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• 1989

This paper proposes a new PWM cycloconverter which can step up input voltage. With input reactors ac power supply acts as current source, and with output capacitors the balanced output voltage is build-up. The converter is modeled with fourth order state equation using dq transformation and the steady state characteristics are evaluated. It is shown that the proposed converter can generate the output voltage 2-5 times greater than input voltage. The output voltage and input current have sinusoidal and smooth waveforms and the converter is capable of voltage build-up. The characteristics of the proposed converter is verified simulation and experiment.

• 한국주조공학회지
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• 제18권5호
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• pp.474-480
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• 1998

Microstructural characteristics of semi-solid state processed hypereutectic Al-Si alloys have been investigated. Main concern of the present study is to investigate the effects of P and Sr addition on the size and morphology change of the primary Si particles. Refinement of the primary Si particles was observed with the addition of P and Sr at the early stage of semi-solid state processing, but such a refining effects became negligible resulting in Si particles with a near-spherical morphology with continuous stirring. This implies that the microstructural transformation mechanism became more dependent to stirring effects than to the alloying effects during semi-solid state processing. Brittle fracture and agglomeration were proposed as the mechanisms for microstructural alterations during semi-solid state processing.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1648-1649
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• 2007

This paper proposes a very novel method which makes it possible that state feedback controller can be designed for unknown dynamic system with measurable states. The RLS algorithm is used for the identification of input-output relationship. A virtual state space representation is derived from the relationship and the SVM(Support Vector Machines) makes the relationship between actual states and virtual states. A state feedback controller can be designed based on the virtual system and the SVM makes the controller be with actual states. The results of this paper can give many opportunities that the state feedback control can be applied for unknown dynamic systems

• 한국분말재료학회지
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• 제18권6호
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• pp.496-501
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• 2011

In this study, the effect of milling time on the microstructure and phase transformation behaviors of Ni-12 wt.%B powders was investigated using vibratory ball milling process. X-ray diffraction patterns showed that the phase transformation of mixed Ni-B elemental powder occurred after 50 hours of milling, with a formation of nickel boride phases. Through the study of microstructures in mechanical alloying process, it was considered that ball milling strongly accelerates solid-state diffusions of the Ni and B atoms during mechanical alloying process. The results of X-ray photoelectron spectroscopy showed that most of B atoms in the powder were linked to Ni with a formation of nickel boride phases after 200 hours of milling. It was finally concluded that mechanical alloying using ball milling process is feasible to synthesize fine and uniform nickel boride powders.

• 전자공학회논문지 IE
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• 제44권4호
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• pp.19-25
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• 2007

본 논문에서는 일반적으로 시변 선형 시스템에 존재하는 불확실성에 대한 해석을 위하여 입력-상태 변환을 고려하였다. 이는 불확실성에 대한 유계 범위를 결정하는데 중요한 역할을 한다. 그러므로 불확실성을 갖는 선형 시변 시스템에 대한 입력-상태 변환을 적용하여 선형 시불변 시스템으로 변환될 수 있는 불확실성의 유계 범위에 대하여 논의하였으며 입력-상태 변환을 위한 필요충분조건을 제시하였다. 변환된 시스템은 다중 적분기를 갖는 시스템으로 표현되며, 예제를 통하여 제안된 알고리즘을 확인하고, 검토하였다.

• Journal of Power Electronics
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• 제13권3호
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• pp.400-408
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• 2013

This paper presents a discrete state-space controller using state feedback control and feed-forward decoupling to provide a desirable control bandwidth and control stability for dynamic voltage restorers (DVR). The paper initially discusses three typical applications of a DVR. The load-side capacitor DVR topology is preferred because of its better filtering capability. The proposed DVR controller offers almost full controllability because of the multi-feedback of state variables, including one-beat delay feedback. Feed-forward decoupling is usually employed to prevent disturbances of the load current and source voltage. Directly obtaining the feed-forward paths of the load current and source voltage in the discrete domain is a complicated process. Fortunately, the full feed-forward decoupling strategy can be easily applied to the discrete state-space controller by means of continuous transformation. Simulation and experimental results from a digital signal processor-based system are included to support theoretical analysis.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2019년도 춘계학술발표대회
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• pp.451-454
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• 2019

In this paper, we propose a verifiable image transformation networks to transform face sketch to photo and vice versa. Face sketch-photo is very popular in computer vision applications. It has been used in some specific official departments such as law enforcement and digital entertainment. There are several existing face sketch-photo synthesizing methods that use feed-forward convolution neural networks; however, it is hard to assure whether the results of the methods are well mapped by depending only on loss values or accuracy results alone. In our approach, we use two Resnet encoder-decoder networks as image transformation networks. One is for sketch-photo and another is for photo-sketch. They depend on each other to verify their output results during training. For example, using photo-sketch transformation networks to verify the photo result of sketch-photo by inputting the result to the photo-sketch transformation networks and find loss between the reversed transformed result with ground-truth sketch. Likely, we can verify the sketch result as well in a reverse way. Our networks contain two loss functions such as sketch-photo loss and photo-sketch loss for the basic transformation stages and the other two-loss functions such as sketch-photo verification loss and photo-sketch verification loss for the verification stages. Our experiment results on CUFS dataset achieve reasonable results compared with the state-of-the-art approaches.

• 방송공학회논문지
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• 제27권5호
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• pp.685-693
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• 2022

디지털 전환과 비대면 소통 플랫폼에 대한 요구로 메타버스가 주목받고 있지만, 원활한 의사소통을 돕는 대화 시스템이 아직 메타버스에서는 널리 적용되지 않았다. 본 연구에서는 메타버스에 대화 시스템을 적용하는 경우 메타버스에서의 주변 상황에 대한 정보를 이용하여 기존의 대화 상태를 수정하는 방법을 제안한다. 대화와 상황에 대한 정보를 모두 활용하는 본 모델은 대화 상태를 추적하는 모듈과 상황 상태를 추적하는 모듈, 그리고 추적한 상황 상태와 대화 상태를 비교하여 수정하는 알고리즘으로 구성된다. 사용자의 의도를 재확인하는 대화가 추가됨에 따라 잘못된 대화 상태를 수정할 수 있고, 대화 시스템의 정확도 향상이 가능하다.

• Journal of applied mathematics & informatics
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• 제3권2호
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• pp.117-128
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• 1996

Complementation theory in krein spaces can be extended for any self-adjoint transformation. There is a close relation between Julia operators and linear systems. The theory of Julia operators can be used to construct distinct Krein spaces which are the state spaces of extended canonical linear systems with given transfer function.