• 대한원격탐사학회지
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• 제10권2호
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• pp.49-62
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• 1994

Look direction bias in a single look SAR image can often be misinterpreted in the geological application of radar data. This paper investigates digital processing techniques for SAR image data integration and compensation of the SAR data look direction bias. The two important approaches for reducing look direction bias and integration of multiple SAR data sets are (1) principal component analysis (PCA), and (2) wavelet transform(WT) integration techniques. These two methods were investigated and tested with the ERS-1 (VV-polarization) and CCRS*s airborne (HH-polarization) C-SAR image data sets recorded over the Sudbury test site, Canada. The PCA technique has been very effective for integration of more than two layers of digital image data. When there only two sets of SAR data are available, the PCA thchnique requires at least one more set of auxiliary data for proper rendition of the fine surface features. The WT processing approach of SAR data integration utilizes the property which decomposes images into approximated image ( low frequencies) characterizing the spatially large and relatively distinct structures, and detailed image (high frequencies) in which the information on detailed fine structures are preserved. The test results with the ERS-1and CCRS*s C-SAR data indicate that the new WT approach is more efficient and robust in enhancibng the fine details of the multiple SAR images than the PCA approach.

• 한국융합학회논문지
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• 제10권9호
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• pp.47-53
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• 2019

본 논문은 소프트웨어 및 제품의 개발운영 및 개발보안운영에 대한 특성을 검토하고 소프트웨어 코드 관점에서 사용 분석도구를 고찰하였다. 또한 보안 설계규칙을 고려할 때 인적인 요소의 중요성과 이를 강화해야 할 필요성이 강조되었다. 본 논문에서는 개발보안운영을 고려할 때 절차적인 요소의 관점에서 신속하고 정확한 의사결정에 중점을 두고 변화를 관리하는 안전한 프로세스에 대해 분석하였다. 또한 본 논문에서는 개발보안운영 특성과 관련하여 성숙도 모델 분석의 필요성을 논의하였고, 이에 따른 동적인 요소와 정적인 요소의 강도 및 통합 요소에 대한 세부 절차를 통해 분석요소의 의미를 분석하였다. 본 논문에서는 위협모델링 및 컴플라이언스 그리고 통제를 위한 스캔 활동이나 코드 분석과 같은 요소에 대해서도 분석하였다.

• 대한조선학회논문집
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• 제45권2호
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• pp.168-174
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• 2008

To calculate the fluid-structure interaction(FSI) problem rationally, it should be the basic technology to analyse each domain of fluid and structure accurately. In this paper, a new FSI analysis algorithm was introduced using the 3D solid finite element for structural analysis and CFD code based on the HCIB method for viscous flow analysis. The fluid and structural domain were analysed successively and alternatively in time domain. The structural domain was analysed by the Newmark-b direct time integration scheme using the pressure field calculated by the CFD code. The results for example calculation were compared with other research and it was shown that those coincided each other. So we can conclude that the developed algorithm can be applied to the general FSI problems.

• 한국컴퓨터정보학회논문지
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• 제22권1호
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• pp.49-56
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• 2017

In this paper we propose the approach for big data integration so as to analyze, visualize and predict the future of the trend of the market, and that is to get the integration data model using the R language which is the future of the statistics and the Hadoop which is a parallel processing for the data. As four approaching methods using R and Hadoop, ff package in R, R and Streaming as Hadoop utility, and Rhipe and RHadoop as R and Hadoop interface packages are used, and the strength and weakness of four methods are described and analyzed, so Rhipe and RHadoop are proposed as a complete set of data integration model. The integration of R, which is popular for processing statistical algorithm and Hadoop contains Distributed File System and resource management platform and can implement the MapReduce programming model gives us a new environment where in R code can be written and deployed in Hadoop without any data movement. This model allows us to predictive analysis with high performance and deep understand over the big data.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.675-680
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• 2001

In this study, a fluid/structure coupled analysis system using computational fluid dynamics and computational structural dynamics has been developed. The unsteady flow fields are predicted using unstructured Euler code. Coupled time-integration method (CTIM) was applied to computer simulation of the flow-induced vibration phenomena. To investigate the interaction effect of shock motions, 2-DOF airfoil systems have been studied in the subsonic and transonic flow region. Also, aeroelastic analyses for the airfoil with an arbitrary object are performed to show the analysis capability and interference effects for the complex geometries. The present results show the flutter stabilities and characteristics of aeroelastic responses with moving shock effects.

• Structural Engineering and Mechanics
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• 제59권2호
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• pp.243-259
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• 2016

This research develops a finite element code for the transient dynamic analysis of tapered fiber reinforced polymer (FRP) poles with hollow circular cross-section and flexible joints used in power transmission lines. The FRP poles are modeled by tapered beam elements and their flexible joints by a rotational spring. To solve the time equations of transient dynamic analysis, precise time integration method is utilized. In order to verify the utilized formulations, a typical jointed FRP pole under step, triangular and sine pulses is analyzed by the developed finite element code and also ANSYS commercial finite element software for comparison. Thereafter, the effect of joint flexibility on its dynamic behavior is investigated. It is observed that by increasing the joint stiffness, the amplitude of the pole tip deflection history decreases, and the time of occurrence of the maximum deflection is earlier.

• International Journal of Aeronautical and Space Sciences
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• 제7권2호
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• pp.155-174
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• 2006

Parabolized stability equations for compressible flows in general curvilinear coordinate system are derived to deal with a broad range of transition prediction problems on complex geometry. A highly accurate finite difference PSE code has been developed using an implicit marching procedure. Compressible and incompressible flat plate flow stability under two-dimensional and three¬dimensional disturbances has been investigated to test the present code. Results of the present computation are found to be in good agreement with the multiple scale analysis and DNS data. Stability calculation results by the present PSE code for compressible boundary layer at Mach numbers ranging from 0.02 to 1.5 are also presented and are again seen to be as accurate as the spectral method.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.673-684
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• 2024

STREAM, developed by the Computational Reactor Physics and Experiment laboratory (CORE) of the Ulsan National Institute of Science and Technology (UNIST), is a deterministic neutron- and photon-transport code primarily designed for light water reactor (LWR) analysis. Initially, the photon module in STREAM did not account for fluorescence and bremsstrahlung photons. This article presents recent developments regarding the integration of atomic relaxation and bremsstrahlung models into the existing photon module, thus allowing for the transport of secondary photons. The photon flux and photon heating computed with the newly incorporated models is compared to results obtained with the Monte Carlo code MCS. The incorporation of secondary photons has substantially improved the accuracy of photon flux calculations, particularly in scenarios involving strong gamma emitters. However, it is essential to note that despite the consideration of secondary photon sources, there is no noticeable improvement in the photon heating for LWR problems when compared to the photon heating obtained with the previous version of STREAM.

• 한국항공우주학회지
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• 제32권6호
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• pp.23-33
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• 2004

다분야 통합 최적화 설계 환경을 제공하는 소프트웨어 체계인 MDO 프레임워크 개발을 위해서는 다양한 운영체계와 언어에서 개발된 해석코드들의 통합, CAD 및 데이터베이스 시스템과의 통합, 복잡한 GUI 환경의 구현 등이 필수적으로 요구되고 해석코드의 추가, 새로운 MDO 기법의 도입에 따른 수정 및 확장에 대한 고려가 충분히 이루어져야 한다. 본 논문에서는 MDO 프레임워크의 설계단계부터 고려되어야 할 사항들과 각 구성요소들의 시스템 통합 방법을 연구, 적용 방안을 제시하며 이를 바탕으로 비행체 통합 최적설계 시스템 환경을 구현하였다. MDF 및 CO 기법 등 대표적인 MDO 기법을 적용할 수 있는 데이터베이스 설계과정을 정립하고, 구현된 통합 최적설계 시스템을 이용하여 전투기 날개 형상 최적 설계를 수행하여 개발된 MDO 프레임워크의 효율성 및 유용성을 검증하였다. 구배 기반 최적화 기법을 이용하여 삼십번의 설계 반복으로 최적 날개 형상을 도출하였다.

• 시큐리티연구
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• 제32호
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• pp.177-204
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• 2012

본 연구는 민간조사 전문직업화의 실태를 분석하여, 이를 기초로 향후 민간조사업의 직업전문성을 제고하기 위한 방안을 모색해 보고자 하는데 그 목적이 있다. 이를 위해 이론적 논의와 선행연구를 바탕으로 전문직업화 과정을 밝히는 구조적인 접근방식의 전문직 특징인 전문협회, 전문지식, 교육과정, 자격제도, 윤리규정의 네 가지 요소를 중심으로 민간조사업의 전문직업화 실태를 분석하였다. 실태분석 결과를 바탕으로 민간조사업의 직업전문성을 제고하기 위해서는 법인화를 위한 관련 협회들 간의 적극적인 노력, 전문지식 편중성의 극복, 전문교과 과정의 편성 운영, 공인화된 자격제도로의 전환, 윤리강령의 제정 등이 요구된다고 할 수 있다.