• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.665-666
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• 2015

Recently BIM technology has been expanded for using in construction project. However its spread has been delayed than the initial expectations, due to the high-cost of BIM infrastructure development, the lack of regulations, the lack of process and so forth. In construction site phase, especially the analysis of current research trend about IT technologies, virtualization and BIM service, data exchange such as drawing, 3D model, object data, properties using cloud computing and virtual server system is defined as a most successful solution. The purpose of this study is enable the cloud computing BIM server to provide several main function such as edit a model, 3D model viewer and checker, mark-up, snapshot in high-performance quality by proper design of VDI system. Concurrent client connection performance is a main technical index of VDI. Through test-bed server client, developed VDI system's multi-connect control will be evaluated. The performance-test result of BIM server VDI will effect to development direction of cloud computing BIM service for commercialization.

• 한국멀티미디어학회논문지
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• 제18권12호
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• pp.1439-1444
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• 2015

Measuring spectral reflectance can be regarded as obtaining inherent color parameters, and spectral reflectance has been used in image processing. Model-based spectrum recovering, one of the method for obtaining spectral reflectance, uses ordinary camera with multiple illuminations. Conventional model-based methods allow to recover spectral reflectance efficiently by using only a few parameters, however it requires some parameters such as power spectrum of illuminations and spectrum sensitivity of camera. In this paper, we propose an enhanced model-based spectrum recovering method without pre-measured parameters: power spectrum of illuminations and spectrum sensitivity of camera. Instead of measuring each parameters, spectral reflectance can be efficiently recovered by estimating and using the spectrum characteristic matrix which contains spectrum parameters: basis function, power spectrum of illumination, and spectrum sensitivity of camera. The spectrum characteristic matrix can be easily estimated using captured images from scenes with color checker under multiple illuminations. Additionally, we suggest fast recovering method preserving positive constraint of spectrum by nonnegative basis function of spectral reflectance. Results of our method showed accurately reconstructed spectral reflectance and fast constrained estimation with unmeasured camera and illumination. As our method could be conducted conveniently, measuring spectral reflectance is expected to be widely used.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.13-30
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• 2019

This paper presents the recent improvements in the DeCART code for HTGR analysis. A new 190-group DeCART cross-section library based on ENDF/B-VII.0 was generated using the KAERI library processing system for HTGR. Two methods for the eigen-mode adjoint flux calculation were implemented. An azimuthal angle discretization method based on the Gaussian quadrature was implemented to reduce the error from the azimuthal angle discretization. A two-level parallelization using MPI and OpenMP was adopted for massive parallel computations. A quadratic depletion solver was implemented to reduce the error involved in the Gd depletion. A module to generate equivalent group constants was implemented for the nodal codes. The capabilities of the DeCART code were improved for geometry handling including an approximate treatment of a cylindrical outer boundary, an explicit border model, the R-G-B checker-board model, and a super-cell model for a hexagonal geometry. The newly improved and implemented functionalities were verified against various numerical benchmarks such as OECD/MHTGR-350 benchmark phase III problems, two-dimensional high temperature gas cooled reactor benchmark problems derived from the MHTGR-350 reference design, and numerical benchmark problems based on the compact nuclear power source experiment by comparing the DeCART solutions with the Monte-Carlo reference solutions obtained using the McCARD code.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.181-183
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• 2002

The accurate permeability for preform is critical to model and design the impregnation of fluid resin in the composite manufacturing process. In this study, the in-plane and transverse permeability for a woven fabric are predicted numerically through the coupled flow model which combines microscopic with macroscopic flow. The microscopic and macroscopic flow which are flows within the micro-unit and macro-unit cell, respectively, are calculated by using 3-D CVFEM(control volume finite element method). To avoid checker-board pressure field and improve the efficiency on numerical computation, A new interpolation function for velocity is proposed on the basis of analytic solutions. The permeability of plain woven fabric is measured through unidirectional flow experiment and compared with the permeability calculated numerically. Based on the good agreement of the results, the relationships between the permeability and the structures of preform such as the fiber volume fraction and stacking effect can be understood. The reverse and the simple stacking are taken in account. Unlike past literatures, this study is based on more realistic unit cell and the improved prediction of permeability can be achieved. It is observed that in-plane flow is more dominant than transverse flow in the real flow through preform and the stacking effect of multi-layered preform is negligible. Consequently, the proposed coupled flow model can be applied to modeling of real composite materials processing.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.68-70
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• 2002

Prediction of 3-D permeability tensor for multi-axial preform is critical to model and design the manufacturing process of composites by considering resin flow through the multi-axial fiber structure. In this study, the in-plane and transverse permeabilities for braided preform are predicted numerically. The flow analyses are calculated by using 3-D CVFEM(control volume finite element method) for macro-unit cells. To avoid checker-board pressure field and improve the efficiency of numerical computation, a new interpolation function for velocity is proposed on the basis of analytic solutions. Permeability of a braided preform is measured through unidirectional flow experiment and compared with the permeability calculated numerically. Unlike other studies, the current study is based on more realistic unit cell and prediction of permeability is improved.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.1751-1754
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• 2003

CCD Camera System으로 capture 한 image를 표준 display장치로 재현할 때 capture 할 당시의 원 피사체의 모습을 그대로 재현하여야만 한다. 그러나 일반 consumer 용 camera system의 CCD channel spectral sensitivity 특성이 인간의 spectral sensitivity(1(λ), m(λ), 5(λ)) 특성과 일치하지 않고, linear transform의 관계도 성립하지 않음으로써 capturing시 근본적인 color error가 발생하게 된다. 기존의 CCD Camera System 에서는 CCD sensor 의 color 정보와 display 장치의 color 정보와의 단순한 산술적인 관계로 color를 재구성하는 방법을 사용하고 있어 원 피사체의 color 를 그대로 재현할 수가 없다. 본 논문에서 제시하는 알고리즘은 CCD 의 channel spectral sensitivity특성 과 CIE-color matching function과의 관계를 고려하여 color를 재구성함으로써 color error를 줄이도록 하였다 제시된 알고리즘의 color error를 검증하기 위하여 물체의 고유반사율을 알고 있는 AGFA IT8.7-2 test chart(283 spectra), Dupont Paint Chips(120 spectra), Mcbeth Color Checker(64 spectra) 및 Natural Objects(170 spectra) 등 다양한 objects spectra(637 spectra) [1][2]를 이용하여 기존 방법의 알고리즘과 비교하여 보았다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 춘계학술발표대회
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• pp.493-496
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• 2016

차량 전장용 소프트웨어의 안정성을 플랫폼 단계에서 테스트 및 검증을 수행하면 많은 비용이 소요된다. 본 연구에서는 플랫폼 단계에서 차량용 내장형 소프트웨어를 테스트하기 이전에 Spin 모델 검증기를 활용하여 전장용 소프트웨어의 기본단위인 타스크들의 행위를 모의 실험함으로써 시스템의 설계오류를 검증할 수 있는 도구를 개발하였다. 본 연구에서는 운영체제와 환경설정 및 제어 프로그램이 수행할 타스크들을 모델로 구축하고, 모델 검증 도구 Spin을 이용하여 타스크의 상태변화를 확인할 수 있었으며, NuSMV를 이용한 방식과 비교하여 다양한 장점들을 확인하였다.

• 전자공학회논문지B
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• 제29B권1호
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• pp.18-25
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• 1992

In this paper, a rule checker which aids in composing a consistent knowledge base by checking redundancies and inconsistencies in a knowledge base is proposed. The proposed algorithm checks the rules by representing the rule connections as a network . The standard model of the rules adapted in this algorithm is in the Conjunctive Normal Form which includes NOT's, and rules of conventional expert system can be checked by converting them into the standard form by a rule form at converter. When compared with Ginsberg's KB-reducer which is conceptually most similar to the proposed algorithm among existing methods,it is shown by a computer simulation that with 360 rules, the checking time is three times faster and the rate increased as the number of rules increased, but the total memory requirement of the proposed agorithm is 1.2 times larger. The proposed algorithm has further advantages in that it can check circular rule chains and can find the paths of the redundant and inconsistent rules.

• 스마트미디어저널
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• 제7권4호
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• pp.37-43
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• 2018

Most of fruit quality classification has been done by time consuming, inaccurate and intensive manual labor. This study proposed an automated fruit grading system based on appearances and internal flavors. In this study, image processing technique and a weight checker were used to measure the value of appearance features and the near infrared spectroscopy analysis method was used to estimate the value of internal flavors. Additionally, I suggested 8x8x5x5 ANN based fruit quality classifier model to grade fruits quality. The proposed automated fruit quality classification system is expected to be very beneficial for many farms where heavy manual labor is usually needed for fruit quality classification.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.593-600
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• 2009

In Korea, the government has developed SEUMTER, an administration system for building related public service, to facilitate and promote the electronic submission and permission activities. SEUMTER is progressing legality system based on 2D drawing for building administration permission service. However, there are a lot of problems related to legality system owing to complexity of Korea regulation relation and structure, inefficiency of legality system based on 2D drawing, duplication examination of document (soliciting forms for civil affairs) and drawing. Therefore, the purpose of this study is to develop legality system for building administration permission service based on BIM in Korea. To achieve this purpose, the authors have investigated permission procedure and regulation structure that is used in current building administration permission and suggested permission procedure and regulation structure for legality system based on BIM. In addition, the authors have investigated element technologies (for examples, method of structured regulation, BIM model checker, Viewer, etc) for legality system based on BIM. Finally, the authors have suggested strategy and hereafter direction for application of legality system based on BIM.