• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.2
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• pp.181-189
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• 2021

In order to increase the practical usability of the virtual reality(VR)-based BIM object in the construction site, the difference between the virtual image and the real image should be resolved, and when it is applied to the construction schedule management function, it is necessary to reduce the image gap between the virtual completion and the actual completion. In this study, in order to solve this problem, a prototype of 4D model is developed in which augmented reality (AR) and 3D printing technologies are linked, and the practical usability of a 4D model linked with two technologies is verified. When a schedule simulation is implemented by combining a three-dimensional output and an AR object, it is possible to provide more intuitive information as a tangible image-based schedule information when compared to a simple VR-based 4D model. In this study, a methodology and system development of an AR implementation system in which subsequent activities are simulated in 4D model using markers on 3D printing outputs are attempted.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1132-1135
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• 2004

Recently. our construction industry is using 4D-CAD system but the public Database (DB) for the 4D-CAD system is insufficiently built. It is difficult to connect 4D-CAD system information such as schedule, drawings. Therefore this study suggest a methodology to link the 4D-CAD system information with work breakdown structure(WBS) and the methodology suggested in this study was applied to a 4D-CAD system

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.8
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• pp.79-86
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• 1999

A simulation of 10 Gbps optical fiber transmission system using DCf(dispersion compensating fiber) for the dispersion compensation is performed. In order to analyze the NRZ pulse propagation in nonlinear, dispersive and lossy fiber, the split-step finite element method that is combination of finite element method and finite difference method is used. Also, we obtained the optical eye diagram and BER characteristics at the receiver of the system that is contained the optical amplifier and system noises. As a result of simulation, we obtain that the dispersion penalty is about 0.8dB after 50km transmission and the receiver sensitivities at $10^{-9}$ BER are -27.4dBm with EDFA pre-amplifier of 12dB gain and -15.6dBm without EDFA.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.611-619
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• 2008

2.5D Mapping system that embody in this paper can make new design by doing draping to live various texture and model picture image of fashion clothes by pattern, and can confirm clothes work to simulation without producing direction sample or product directly. Also, the system can support function that can forecast fabric design and state of end article exactly, and the system can bring competitive power elevation of fashion industry and cost-cutting effect by doing draping using database of fabric and model picture image. 2.5D Mapping system composed and embodied by mesh warp algorithm module, light and shade extraction and application module, mapping path extraction module, mesh creation and transformation module, and 2.5D mapping module for more natural draping. Future work plans to study 3D fashion design system that graft together 3D clothes technology and 3D human body embodiment technology to do based on embodiment technology of 2.5D mapping system and overcomes expression limit of 2.5D mapping technology.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.12 s.115
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• pp.1164-1171
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• 2006

In this paper, a simple and nonlinear MMSE detector is derived from the conventional linear MMSE detector to improve the system performance in turbo processing MIMO system and a new turbo processing MIMO system with nonlinear MMSE detector and Gaussian approximation is proposed. In turbo coded turbo processing MIMO system, the proposed system of M=N=4 performs about 0.5 dB better than the conventional system and the proposed system of M=N=8 performs about 0.4 dB better than conventional system at 1 % FER. In addition, the average number of outer iterations of proposed system shows lower than that of conventional system. This is caused by the fact that the nonlinear MMSE detector of proposed system decides soft-outputs of coded bits based on the observation of received signals, so that it can reduce the uncertainty region in estimating the coded bits.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1714-1720
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• 2012

The purpose of the study was to evaluation of the radiation dose reduction and the possibility of the maintainability of the adequate image quality using various automatic exposure control (AEC) systems in multi-detector computed tomography (MDCT). We used three AEC systems for the study: General Electric Healthcare (Auto-mA 3D), Philips Medical systems (DoseRight) and Siemens Medical Solutions (Care Dose 4D). The general scanning protocol was created for the each examination with the same scanning parameters as many as possible. In the various AEC systems, the evaluation of reduced-dose was evaluated by comparing to fixed mAs with using human phantom. The image quality of the phantom was evaluated with measuring the image noise (standard deviation) by insert regions of interests. Finally, when we applied to AEC for three manufacturers, the radiation dose reduction decreased each 35.3% in the Auto-mA 3D, 58.2% in the DoseRight, and 48.6% in the Care Dose 4D. And, there was not statistical significant difference among the image quality in the Strong/Weak of the Care Dose 4D(P=.269). This applies to variety of the AEC systems which will be very useful to reduce the dose and to maintain the high quality.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06b
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• pp.101-106
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• 2007

본 논문에서는 SOA(Service Oriented Architecture) 기반으로 국가 R&D 정보의 종합 조회 기능을 제공하는 국가 R&D 정보시스템(RnDIS: R&D Information System)을 설계 및 구현하였다. 물리적으로 분산되고 각각 별도의 DB를 구성하여 활용하는 이질적인 4개의 응용시스템의 기능을 효과적으로 연계 및 활용하기 위해 유연하며 확장이 용이한 SOA를 채택하였다. 서비스의 식별, 정의, 분석 등의 개발을 위해 CBD 방법론을 확장한 새로운 서비스 개발방법론을 정의 및 활용하였으며, RnDIS를 위해 4개의 어플리케이션 서비스와 4개의 비즈니스 프로세스 서비스를 정의 및 설계하였다. 어플리케이션 서비스는 기존의 자바코드로부터 WSDL(Web Service Description Language)을 생성하는 래핑(wrapping) 방식을 사용하여 구현하였며, 비즈니스 프로세스 서비스는 BPEL(Business Process Execution Language) 엔진을 이용하여 어플리케이션 서비스를 조합하는 방식을 이용하여 구현하였다. RnDIS는 NTIS(National Science and Technology Information System) 공식 홈페이지(http://www.ntis.go.kr)의 종합검색 메뉴로 시범서비스 되고 있으며, 향후 서비스 대상 데이터의 확장과 기능 추가를 통해 정식 서비스를 오픈 할 예정이다.

• Journal of Digital Convergence
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• v.18 no.11
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• pp.187-194
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• 2020

This study present to Framework & R&D direction of the 3d printing Integrated Control & Monitoring System. To ensure this purpose, we developed integrated 3d printing control system Framework for DED & PBF and we introduce 4 monitoring system include photo diode, gas flow, acoustic and spectrometer sensors. For this study, we utilize metal 3d printing system from Conception., OKE Tech and DE&T who are still developing Metal 3D Printing Technology since 2017. In the result, we represent the latest 3D Printing Control and Monitoring System for the next 3D Printing researcher and we hope this study will be used as a basic reference and data for Cooperation between mechanic, electronic and material fields.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.254-258
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• 2007

본 논문에서는 OFDM 변조와 단축블록터보코드를 사용하는 시스템에서 단축블록터보코드를 반복 복호하는 과정에서 채널상태정보(Channel State Information : CSI)값을 적용한 방법을 새롭게 제안하였다. 새롭게 제안된 시스템의 경우 1회의 같은 반복 횟수를 가지는 경우에 BER 성능이 신호의 변조방식에 따라 4.5[dB] $\sim$ 10.0[dB] 정도의 뛰어난 전능 향상을 보였다. 또한 CSI값을 적용하고 1회 반복 복호한 시스템이 CSI값을 적용하지 않은 기존의 복호 시스템의 4회 반복 복호한 경우보다도 1[dB] $\sim$ 7.0[dB]의 성능 향상을 보임으로써 반복 복호의 시간을 70[%] 이상 감소시킬 수 있다. 따라서 단축블록터보코드를 반복 복호하는 경우에 CSI값을 적용한 시스템이 뛰어난 성능 향상과 더불어 반복 복호 시간을 줄임을 알 수 있었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1A
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• pp.36-43
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• 2008

In this paper, we propose an optimal relay selection scheme for decode-and-forward relaying systems. The optimal relay selection minimizes the number of time slots used to relay source's signal and maximizes an end-to-end signal-to-noise ratio. However, decode-and-forward relaying systems require additional overhead for the optimal relay selection. Assuming independent and identically distributed Rayleigh fading channels, we provide exact and closed-form expressions for the outage probability of capacity and the bit error rate for decode-and-forward relaying systems with the optimal relay selection. It is shown that the analytic results are perfectly matched with the simulated ones. When the numbers of relay nodes are 2, 4, and 8, and the numbers of time slots for overhead are 1, 2, and 4, respectively, the proposed system achieves 1 dB, 2 dB, and 3 dB gains at 1% bit error rate, respectively, and 0.5 dB, 4 dB, and 12 dB gains at 1% outage probability for 1 bps/Hz, respectively, over the conventional decode-and-forward relaying system.