• 대한수학회논문집
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• 제37권4호
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• pp.1259-1267
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• 2022

In this paper we present a full circle approximation method using parametric polynomial curves with algebraic coefficients which are curvature continuous at both endpoints. Our method yields the n-th degree parametric polynomial curves which have a total number of 2n contacts with the full circle at both endpoints and the midpoint. The parametric polynomial approximants have algebraic coefficients involving rational numbers and radicals for degree higher than four. We obtain the exact Hausdorff distances between the circle and the approximation curves.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.706-709
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• 1992

This paper deals with the operation of a parametric transformer through the normalization of system equations. Based on these equations, the effects of excitation voltage waveforms on the performances of the parametric transformer are analyzed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.121-124
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• 2003

In this paper, the non-parametric algorithm to estimate DOA(Direction Of Arrival) of signals is proposed and compared with the multidimensional MUSIC algorithm. This non-parametric algorithm with regularizing sparsity constraints achieves super-resolution and noise suppression, effectively. Also, this algorithm offers the increased resolution and significantly reduced sidelobes.

• 건축사
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• 통권556호
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• pp.86-87
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• 2015

지난 회에서는 parametric tool의 근간이 되는 기본 개념에 대해 간략하게 논의 하였고, 이를 통하여 삼차원 프로그램상의 형태 구현의 논리와 방법이 어떻게 발전해 왔는지에 대해 이야기 해 보았습니다. 전회에 말씀드렸듯이 이번회에서는 최근 실무에서 가장 많이 사용되고 있는 parametric tool에 대해 간략히 알아보도록 하겠습니다. 참고로 이번 회를 마지막으로 parametric tool의 개략적인 소개는 마치도록 하고 현장감 있는 실무에서의 적용에 대해 이야기 해 보도록 하겠습니다.

• 한국진공학회지
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• 제12권1호
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• pp.20-24
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• 2003

Parametric semiconductor model을 이용하여 $In_{\chi}Ga_{1-\ch}As \;(0\leq\chi\leq1)$ 화합물 반도체 박막의 유전함수를 얻었다. Parametric model은 Gaussian-broadened polynomial들의 합으로 임계점에 대한 모델 유전 함수를 묘사하여 InGaAs 화합물의 광학 상수들을 재현할 수 있는 parameterized 함수를 제공하였다. 이러한 parametric 모델을 통하여 임의의 성분비 $\chi$에 대한 파라미터 값들을 얻었고, 이렇게 얻어진 파라미터들로부터 $In_{\chi}Ga_{1-\ch}As \;(0\leq\chi\leq1)$ 화합물 박막의 임의의 성분비에 대한 유전 함수를 얻을 수 있었다.

• 한국CDE학회논문집
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• 제11권3호
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• pp.164-171
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• 2006

As collaborative design and configuration design are of increasing importance in product development, it becomes essential to exchange the feature and parametric CAD models among participants. A history-based parametric method has been proposed and implemented. But each translator which exchanges the feature and parametric information tends to be heavy because to implement duplicated functions such as the identification of the selected geometries, mapping between features which have different attributes. Furthermore. because the history-based parametric translator uses the procedural model as the neutral format, which is the XML macro file, the history-based parametric translators need a geometric modeling kernel to generate an internal explicit geometric model. To ease the problem, we implemented a shared integration platform, the TransCAD. The TransCAD separates translators from the XML macro files. The translators for various CAD systems need to communicate with only the TransCAD. To support the communication with the TransCAD, we exposed the functions of the TransCAD by using the Automation APIs, which is developed by Microsoft. The Automation APIs of the TransCAD consist of the part modeling functions, the data extraction functions, and the utility functions. Each translator uses these functions to translate a parametric CAD model from the sending CAD system into the XML format, or from the in format into the model of the receiving CAD system This paper introduces what the TransCAD is and how it works for the exchange of the feature and parametric models.

• Investigative Magnetic Resonance Imaging
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• 제25권4호
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• pp.300-312
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• 2021

Compressed sensing (CS) has been investigated in magnetic resonance (MR) parametric mapping to reduce scan time. However, the relatively long reconstruction time restricts its widespread applications in the clinic. Recently, deep learning-based methods have shown great potential in accelerating reconstruction time and improving imaging quality in fast MR imaging, although their adaptation to parametric mapping is still in an early stage. In this paper, we proposed a novel deep learning-based framework DEMO for fast and robust MR parametric mapping. Different from current deep learning-based methods, DEMO trains the network in an unsupervised way, which is more practical given that it is difficult to acquire large fully sampled training data of parametric-weighted images. Specifically, a CS-based loss function is used in DEMO to avoid the necessity of using fully sampled k-space data as the label, thus making it an unsupervised learning approach. DEMO reconstructs parametric weighted images and generates a parametric map simultaneously by unrolling an interaction approach in conventional fast MR parametric mapping, which enables multi-tasking learning. Experimental results showed promising performance of the proposed DEMO framework in quantitative MR T1ρ mapping.

• Structural Engineering and Mechanics
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• 제61권4호
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• pp.497-510
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• 2017

A framed structure may be composed of two sub-structures, which are linked by a hinged joint. One sub-structure is the primary system and the other is the secondary system. The primary system, which is subjected to the periodic external load, can give rise to an auto-parametric resonance of the second system. Considering the geometric-stiffness effect produced by the axially internal force, the element equation of motion is derived by the extended Hamilton's principle. The element equations are then assembled into the global non-homogeneous Mathieu-Hill equations. The Newmark's method is introduced to solve the time-history responses of the non-homogeneous Mathieu-Hill equations. The energy-growth exponent/coefficient (EGE/EGC) and a finite-time Lyapunov exponent (FLE) are proposed for determining the auto-parametric instability boundaries of the structural system. The auto-parametric instabilities are numerically analyzed for the two frames. The influence of relative stiffness between the primary and secondary systems on the auto-parametric instability boundaries is investigated. A phenomenon of the "auto-parametric internal resonance" (the auto-parametric resonance of the second system induced by a normal resonance of the primary system) is predicted through the two numerical examples. The risk of auto-parametric internal resonance is emphasized. An auto-parametric resonance experiment of a ${\Gamma}$-shaped frame is conducted for verifying the theoretical predictions and present calculation method.

• 한국전자거래학회지
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• 제9권4호
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• pp.117-136
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• 2004

치열한 경쟁 환경 하에서 빠른 시간 안에 고객이 원하는 제품을 생산해야 하는 즉, 시장 출시까지의 시간 (time to market) 단축의 필요성이 더욱 높아짐에 따라, 제품 설계 시에 협업(collaborative) 설계와 편집(configuration) 설계의 중요성이 커지고 있다. 이를 위해서 효율적인 부품 검색 방법이 필요하고, 그 방법의 하나로써 전자 카달로그 (e-Catalog)가 많이 사용된다. 편집설계를 통한 설계 모델 재사용을 위해서는 파라메트릭 정보가 필수적이다. 따라서 전자 카달로그는 파라메트릭 (parametric) 정보가 포함된 CAD 모델 라이브러리를 제공해야 한다. 그러나 제품의 구성에 따라 무수히 많은 조합이 존재하기 때문에, 기존의 방법으로는 파라메트릭 CAD 모델 라이브러리를 구축하기가 어렵다. 예를 들어, 몰드베이스 종이 카달로그의 한 페이지에는 8000만개 이상의 조합이 존재한다. 이와 같은 문제를 해결하기 위해서, 본 논문에서는 파라메트릭 CAD 모델 자동 생성을 위한 테이블 파라메트릭 (table parametric) 방법을 제안하고, 테이블 파라메트릭 모델을 선정하는 방법과 설계 파라메트릭 세트를 구성하는 방법에 대해서 설명한다. 테이블 파라메트릭 방법을 적용하게 되면, 전자 카달로그 시스템의 분류체계와 테이블 파라메트릭 모델의 설계 파라메터 세트 (design parameters set) 와의 매핑을 통해, 모든 조합의 몰드베이스 CAD 모델을 자동으로 생성할 수 있다.

• International Journal of Control, Automation, and Systems
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• 제3권2호
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• pp.159-165
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• 2005

This paper designs observers for matrix second-order linear systems on the basis of generalized eigenstructure assignment via unified parametric approach. It is shown that the problem is closely related with a type of so-called generalized matrix second-order Sylvester matrix equations. Through establishing two general parametric solutions to this type of matrix equations, two unified complete parametric methods for the proposed observer design problem are presented. Both methods give simple complete parametric expressions for the observer gain matrices. The first one mainly depends on a series of singular value decompositions, and is thus numerically simple and reliable; the second one utilizes the right factorization of the system, and allows eigenvalues of the error system to be set undetermined and sought via certain optimization procedures. A spring-mass system is utilized to show the effect of the proposed approaches.