• Structural Engineering and Mechanics
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• 제27권6호
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• pp.683-696
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• 2007

This article is concerned with the presentation of a time-domain BEM approach applied to the solution of the scalar wave equation for 2D problems. The basic idea is quite simple: the basic variables of the problem at time $t_n$ (potential and flux) are computed with the results related to the potential and to its time derivative at time $t_{n-1}$ playing the role of "initial conditions". This time-marching scheme needs the computation of the potential and its time derivative at all boundary nodes and internal points, as well as the entire discretization of the domain. The convolution integrals of the standard time-domain BEM formulation, however, are not computed; the matrices assembled, only at the initial time interval, are those related to the potential, flux and to the potential time derivative. Two examples are presented and discussed at the end of the article, in order to verify the accuracy and potentialities of the proposed formulation.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제5권1호
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• pp.7-12
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• 2016

사용자 인터페이스는 프로그램 상호 연동의 중요한 요소가 된다. 사용자 인터페이스에서 발생되는 오류는 전체 시스템에 영향을 주게 되고, 그 결과 고객의 만족도가 낮아진다. 따라서 도메인 단계에서 신뢰성 있는 분석을 위하여 사용자 인터페이스의 형태를 분석할 수 있는 방법이 필요하게 된다. 본 논문에서는 이와 같은 문제를 해결하기 위하여 도메인 분석의 신뢰성 향상을 위한 사용자 인터페이스의 추출 방법과 기준을 제시하고자 한다.

• International Journal of CAD/CAM
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• 제11권1호
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• pp.1-10
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• 2011

Product lifecycle management (PLM) is a new business strategy for enterprise's product R&D. A PLM system holds and maintaining the integrity of the product data produced throughout its entire lifecycle. There is, therefore, a need to build a safe and effective product data model to support PLM system. The paper proposes a domain-based product data model for PLM. The domain modeling method is introduced, including the domain concept and its defining standard along the product evolution process. The product data model in every domain is explained, and the mapping rules among these models are discussed. Mapped successively among these models, product data can be successfully realized the dynamic evolution and the historical traceability in PLM system.

• ETRI Journal
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• 제28권1호
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• pp.51-58
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• 2006

In this paper, we propose a method of applying a lifting-based wavelet domain e-median filter (LBWDEMF) for image restoration. LBWDEMF helps in reducing the number of computations. An e-median filter is a type of modified median filter that processes each pixel of the output of a standard median filter in a binary manner, keeping the output of the median filter unchanged or replacing it with the original pixel value. Binary decision-making is controlled by comparing the absolute difference of the median filter output and the original image to a preset threshold. In addition, the advantage of LBWDEMF is that probabilities of encountering root images are spread over sub-band images, and therefore the e-median filter is unlikely to encounter root images at an early stage of iterations and generates a better result as iteration increases. The proposed method transforms an image into the wavelet domain using lifting-based wavelet filters, then applies an e-median filter in the wavelet domain, transforms the result into the spatial domain, and finally goes through one spatial domain e-median filter to produce the final restored image. Moreover, in order to validate the effectiveness of the proposed method we compare the result obtained using the proposed method to those using a spatial domain median filter (SDMF), spatial domain e-median filter (SDEMF), and wavelet thresholding method. Experimental results show that the proposed method is superior to SDMF, SDEMF, and wavelet thresholding in terms of image restoration.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권8호
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• pp.4174-4190
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• 2019

IEC 62304 is a standard for the medical device software lifecycle. Developers must develop software that complies with all specifications in the standard for licensing. However, because the standard contains not only a large number of specifications, but also domain-specific information and association relationships between specifications, it requires considerable effort and time for developers to understand and interpret the standard. To support developers, this paper presents a method for extracting the contents of the IEC 62304 standard as a goal model, which is the core methodologies of requirements engineering. The proposed method analyzes the grammar of the standard to robustly extract complex structures and various information from standard specifications and define rules that extract goals and links from syntactic element units. We validated the actual extraction process for the standard document experimentally. Based on the extracted goal model, developers can intuitively and efficiently comply with the standard and track specific information within the medical software and standard domains.

• 대한공간정보학회지
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• 제17권1호
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• pp.79-87
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• 2009

ISO TC 211은 지리정보 분야와 관련된 하나의 국제 표준화 기구로서 지구상의 지리적 위치와 직 간접적인 관계있는 사물이나 현상에 대한 표준을 정의 개발한다. ISO TC 211은 기존 연구되어진 핵심 지적 도메인 모델(CCDM : Core Cadastral Domain Model)을 발전시켜 토지 행정 도메인 모델(LADM : Land Administration Domain Model)을 새로운 국제표준화 프로젝트로서 진행하고 있다. 토지 행정 도메인 모델(LADM)은 국제표준화 모델로서 전 세계 많은 국가들이 지적과 관련된 행정 법, 공간 측량적인 구성요소들의 관계를 정의한다. 이를 통해 토지관련 데이터를 효과적으로 관리하고, 나아가 국가들 간의 토지관련 데이터를 공유할 수 있다. 본 연구에서는 기존의 핵심 지적 도메인 모델(CCDM)을 발전시킨 토지 행정 도메인 모델(LADM)의 연구 진행 상황과 내용을 소개하고 토지 행정 도메인 모델의 부동산, 측량, 기하 위상, 법 행정 부분을 우리나라의 한국토지정보시스템에 적용방안을 연구하였다.

• 한국통신학회논문지
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• 제17권9호
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• pp.1029-1039
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• 1992

본 논문은 한글인식 방법중 주파수 변환영역에서 행하는 필터링의 방법을 제시한 것이다. 한글 문자패턴을 2차원 변조처리하여 공간위치에 의존적인 한글자소의 위상문자적 특징을 주파수 영역으로 사상하였고, 이때 변조 주파수를 정규화함으로서 주파수 영역에서 문자의 크기를 정규화 한다. 또한 한글의 각 자소를 발생위치에 따라 분류하여 표준패턴으로 설정하고, 설정된 각 자소의 표준패턴을 자소필터로 사용하여 주파수 영역으로 사상된 문자패턴을 필터링하였다. 한글자소의 분별 파라미터로는 정규화된 상호상관함수와 필터링 결과로 부터 유도된 코히어런스 함수를 산출하여 분별기준을 설정하였으며, 그 결과로서 문자크기의 변화, 자소의 융착, 제한적인 자획의 유실이나 잡음의 혼입등의 요인이 발생하였음 경우에도 한글자소의 분별이 가능하였고 또한 표준패턴을 설정함에 따라 숫자, 영문자등의 분별에도 적용할 수 있었다.

• ETRI Journal
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• 제37권2호
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• pp.369-379
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• 2015

Fault management of virtualized network environments using user-driven network provisioning systems (NPSs) is crucial for guaranteeing seamless virtual network services irrespective of physical infrastructure impairment. The network service interface (NSI) of the Open Grid Forum reflects the need for a common standard management API for the reservation and provisioning of user-driven virtual circuits (VCs) across global networks. NSI-based NPSs (that is, network service agents) can be used to compose user-driven VCs for mission-critical applications in a dynamic multi-domain. In this article, we first attempt to outline the design issues and challenges faced when attempting to provide mission-critical applications using dynamic VCs with a protection that is both user-driven and trustworthy in a dynamic multi-domain environment, to motivate work in this area of research. We also survey representative works that address inter-domain VC protection and qualitatively evaluate them and current NSI against the issues and challenges.

• 비파괴검사학회지
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• 제29권6호
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• pp.579-585
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• 2009

The multifrequency eddy current testing(ECT) have been proposed various frequency mixing algorithms. In this study, we compare these approaches to frequency mixing of ECT signals from steam generator tubes; time-domain optimization, discrete cosine transform-domain optimization. Specifically, in this study, two different frequency mixing algorithms, a time-domain optimization method and a discrete cosine transform(DCT) optimization method, are investigated using the experimental signals captured from the ASME standard tube. The DCT domain optimization method is computationally fast but produces larger amount of residue.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1744-1746
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• 1996

Surface impedance boundary condition(SIBC) concepts are introduced into the finite-difference time-domain(FDTD) method. Lossy conductors are replaced by surface impedance boundary computations reducing the soluton space and producing significant computational savings. Specifically, a surface impedance boundary condition is developed to reduce a lossy dielectric half-space. Since Maxwell's eqations are solved directly, the reflected and transmitted pulse amplitude demonstrate how the reflection and transmision coefficient determine reflected wave amplitude. In this paper, two implementations of reflection coefficient are presented. One implementation is a standard FDTD technique and the other is a FDTD using surface impedence boundary condition(FDTD-SIBC) that are applicabIe over a very large frequency bandwidth. Particulary, an efficient way to transform the time domain results to frequency domain is presented. Thus, frequency domain results are presented in one dimension and are compared with exact results.