• 천문학회보
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• 제46권2호
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• pp.60.3-60.3
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• 2021

Squeezed vacuum injection을 이용한 중력파 검출기의 관측감도 향상 기술은 중력파 검출기 광신호의 양자 잡음을 제어하여 관측감도를 높이는 기술로 이론적으로는 10dB에 가까운 신호 대 잡음비 향상을 달성할 수 있다. 실험실 환경에서는 이미 10dB 이상의 신호 대 잡음비 향상을 달성했으며 실제 중력파 검출기에서는 GEO600의 6dB의 신호 대 잡음비 향상이 현재까지 가장 높은 수준이다. 한국천문연구원에서는 2019년부터 차세대 중력파 검출기 기술개발로 1064 nm 파장의 squeezer 개발을 추진했으며 현재 parametric down conversion을 이용해 squeezed vacuum을 생성하는 공진기를 제작하여 시험하는 단계에 있다. 이 발표에서는 한국천문연구원의 1064 nm squeezer 개발 연구와 개발 현황에 대해 소개하고자 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.163-165
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• 2006

This paper presents a implementation of speed sensorless vector control algorithm of induction motor using MATLAB/SIMULINK amd dSPACE DSl104 R&D board. The estimation of rotor flux linkage and rotor speed is carried out using model reference adaptive system(MRAS) method. Estimated rotor speed is used to speed controller of induction motor. Simulation results are presented to confirm speed sensorless vector control algorithm.

• 충청수학회지
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• 제17권2호
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• pp.111-124
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• 2004

In [4], Dhage proved a result for common fixed point of two self-maps satisfying a contractive condition in D-metric spaces. This note proves a fixed point theorem for five self-maps under weak-compatibility in D-metric space which improves and generalizes the above mentioned result.

• Nonlinear Functional Analysis and Applications
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• 제27권2호
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• pp.309-322
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• 2022

In this paper, we introduce the notion of a new generalized type of rational F-contraction mapping. Further, the concept is used to obtain fixed points in a complete b-metric space. We also prove another unique fixed point theorem in the context of b-metric space. Our results are verified with example.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.2315-2324
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• 2023

Space nuclear reactors are becoming popular in deep space exploration owing to their advantages of high-power density and stability. Following the fourth-generation nuclear reactor technology, a conceptual design of the dual drum-controlled space molten salt reactor (D²-SMSR) is proposed. The reactor concept uses molten salt as fuel and heat pipes for cooling. A new reactivity control strategy that combines control drums and safety drums was adopted. Critical physical characteristics such as neutron energy spectrum, neutron flux distribution, power distribution and burnup depth were calculated. Flow and heat transfer characteristics such as natural convection, velocity and temperature distribution of the D²-SMSR under low gravity conditions were analyzed. The reactivity control effect of the dual-drums strategy was evaluated. Results showed that the D²-SMSR with a fast spectrum could operate for 10 years at the full power of 40 kWth. The D²-SMSR has a high heat transfer coefficient between molten salt and heat pipe, which means that the core has a good heat-exchange performance. The new reactivity control strategy can achieve shutdown with one safety drum or three control drums, ensuring high-security standards. The present study can provide a theoretical reference for the design of space nuclear reactors.

• 한국건축시공학회지
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• 제7권3호
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• pp.91-98
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• 2007

Recently a construction industry introduces information that brings about many advantages in the early planning phase, design phase and construction phase. Especially it replaces 2D, 3D systems(usually using explanation of drawing information) ai 4D CAD(offering a sort of 4D-having relation of construction schedule and 3D drawing information). Nevertheless a 4D has these benefits, it has limits which are not only usually using 3D modeling but also limit of making full use of practical affairs because of a lack of connecting varietals of progress of work. To solve these uppermost limits, this research is presenting unified systems to use in risk management which are efficient management of space and non-space information, space analysis, making full use of data base, introducing GIS system of easy interaction.

• 한국콘텐츠학회논문지
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• 제14권7호
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• pp.1-9
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• 2014

2D 영상 콘텐츠 시퀀스로부터 입체 3D 영상을 생성하는 기존의 2D-3D 변환(conversion) 방법은 제작파이프라인 상에서 많은 수작업이 요구된다. 본 논문에서는 기존 변환 방식의 문제점을 해결하기 위해 대상 장면의 공간을 재구성하는 효율적인 2D-3D 변환 방법을 제안한다. 제안된 방법은 영상 시퀀스를 입체적으로 분석하여 3차원 공간모델을 구성하고 텍스처 재사영 방법을 통해 스테레오 영상을 생성한다. 해석된 장면의 구조 정보를 이용하여 정확한 3D 입체 콘텐츠를 제작할 수 있음을 확인하였다. 제안된 시스템을 이용하여 스테레오그래퍼(stereographer)와 영상 제작자가 2D-3D 입체변환을 효율적으로 진행할 수 있다.

• 디지털산업정보학회논문지
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• 제12권3호
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• pp.157-166
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• 2016

This paper presents the interior space information using 6D-360 degree immersive media video information. And we implement the augmented reality, which includes a variety of information such as position information, movement information of the specific location in the interior space GPS signal does not reach the position information. Augmented reality containing the 6D-360 degree immersive media video information provides the position information and the three dimensional space image information to identify the exact location of a user in an interior space of a moving object as well as a fixed interior space. This paper constitutes a three dimensional image database based on the 6D-360 degree immersive media video information and provides augmented reality service. Therefore, to map the various information to 6D-360 degree immersive media video information, the user can check the plant in the same environment as the actual. It suggests the augmented reality service for the emergency escape and repair to the passengers and employees.

• ETRI Journal
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• 제39권4호
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• pp.493-501
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• 2017

This paper introduces a new motion-synthesis technique for animating multiple characters. At a high level, we introduce a hub-sub-control-point scheme that automatically generates many different spline curves from a user scribble. Then, each spline curve becomes a trajectory along which a 3D character moves. Based on the given curves, our algorithm synthesizes motions using a cyclic motion. In this process, space-time warp curves, which are time-warp curves, are embedded in the 3D environment to control the speed of the motions. Since the space-time warp curve represents a trajectory over the time domain, it enables us to verify whether the trajectory causes any collisions between characters by simply checking whether two space-time warp curves intersect. In addition, it is possible to edit space-time warp curves at run time to change the speed of the characters. We use several experiments to demonstrate that the proposed algorithm can efficiently synthesize a group of character motions. Our method creates collision-avoiding trajectories ten times faster than those created manually.

• Journal of information and communication convergence engineering
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• 제8권4호
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• pp.411-415
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• 2010

Conventional Augmented Reality has used data gloves or markers for smooth interaction between objects and background. This causes inconvenience of use and lower immersion. To build up immersion in Augmented Reality, additional input devices must be removed. For this purpose, accurate recognition of space coordinates is needed even with no attachment of markers. This paper proposes a method to create virtual space coordinates for interaction without wearing additional input devices so as to improve immersion in Augmented Reality. The acquired image was projected to 2D space and vanishing lines were extracted to calculate the virtual space coordinates. Then the sizes of the inserted objects were varied in accordance with the size of the virtual coordinates area based on the image projected onto the 2D coordinates. This resulted in improved immersion. This method can increase the efficiency of object creation by excluding the use of a 3D modeler for creation of 3D objects.