• 한국정보과학회논문지:시스템및이론
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• 제33권1_2호
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• pp.128-136
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• 2006

점묘화(stippling)는 펜과 잉크를 이용한 수많은 점들로 대상을 표현하는 예술 기법이다. 기존 비사실적 렌더링(Non-Photorealistic Rendering; NPR)에서 점묘화 연구들은 단색의 점들을 사용하여 그레이 영상이나 표면의 재질 등을 표현하였다. 본 논문에서는 2차원 영상의 컬러 정보를 해석하여 다양한 컬러의 점들로 표현하는 새로운 점묘화 기법이 제안된다. 제안된 방법은 입력 영상의 HSV 모델로부터 해석된 정보를 이용하여 컬러 가중치 함수(weight function)를 정의한다. 그리고 정의된 컬러 가중치 함수를 통해 점의 적절한 개수와 크기를 자동으로 계산한다 제안된 방법은 컬러 가중치가 적용된 펜로즈(Penrose) 샘플링을 사용하여 점을 분포하기 위해 소요되는 처리시간을 크게 단축하였다. 그리고 먼셀(Munsell)의 색상모델에 기반한 컬러 지터링(jittering)으로 실제 컬러 점묘화에 가까운 표현을 구현하였다 제안된 컬러 점묘화 기법은 처리속도가 매우 빠르고 다양한 컬러 점들로 영상을 표현하므로 애니메이션, 디지털 아트, 컴퓨터 그래픽 도구 등에 다양하게 활용될 수 있다.

• 전자공학회논문지
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• 제50권1호
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• pp.269-275
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• 2013

본 논문에서는 Extreme Learning Machine(ELM)을 이용한 자기부상시스템 모델링 기법을 제안한다. 자기부상시스템의 모델링을 위하여 일반적으로 테일러 급수를 이용한 선형화 모델이 사용되어져 왔으나, 이런 수학적 기법의 경우 자기부상시스템의 비선형 반영에 한계가 있다는 단점을 가지고 있다. 이러한 단점을 극복하기 위해 본 논문에서는 학습시간이 빠른 특성을 가진 ELM을 이용한 자기부상시스템의 모델링 기법을 제안한다. 제안된 기법은 입력 가중치들과 은닉 바이어스들의 초기값을 무작위로 선택하고 출력 가중치들은 Moore-Penrose의 일반화된 역행렬 방법을 통하여 구해진다. 실험을 통하여 제안된 알고리즘이 자기부상시스템의 모델링에서 수학적 기법에 비해 우수한 성능을 보임을 알 수 있었다.

• Journal of applied mathematics & informatics
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• 제32권1_2호
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• pp.61-74
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• 2014

This paper describes an iterative method for orthogonal projections $AA^+$ and $A^+A$ of an arbitrary matrix A, where $A^+$ represents the Moore-Penrose inverse. Convergence analysis along with the first and second order error estimates of the method are investigated. Three numerical examples are worked out to show the efficacy of our work. The first example is on a full rank matrix, whereas the other two are on full rank and rank deficient randomly generated matrices. The results obtained by the method are compared with those obtained by another iterative method. The performance measures in terms of mean CPU time (MCT) and the error bounds for computing orthogonal projections are listed in tables. If $Z_k$, k = 0,1,2,... represents the k-th iterate obtained by our method then the sequence of the traces {trace($Z_k$)} is a monotonically increasing sequence converging to the rank of (A). Also, the sequence of traces {trace($I-Z_k$)} is a monotonically decreasing sequence converging to the nullity of $A^*$.

• Journal of Mechanical Science and Technology
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• 제18권9호
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• pp.1529-1536
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• 2004

A structure is broken down into a number of substructures by means of the finite element method and the substructures are synthesized for the complete structure. The divided substructures take two types: fixed-free and free-free elements. The flexibility and stiffness matrices of the free-free elements are the Moore-Penrose inverse of each other. Thus, it is not easy to determine the equilibrium equations of the complete structure composed of two mixed types of substructures. This study provides the general form of equilibrium equation of the entire structure through the process of assembling the equilibrium equations of substructures with end conditions of mixed types. Applications demonstrate that the proposed method is effective in the structural analysis of geometrically complicated structures.

• Journal of Chest Surgery
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• 제24권6호
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• pp.585-589
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• 1991

We experienced a rare hepatic tuberculous granuloma with subphrenic abscess. The patient was 45-years old female. She complained the right flank pain and tenderness on the protruding mass for 2 weeks. It was fixed, erythematous and 5x5cm sized mass, which was thought as cold abscess. She has done the hysterectomy as endometriosis at November 1990. Under general endotracheal anesthesia, the mass was incised, but the pus was not found. The needle aspiration was done through the 8th ICS, then the yellowish non-foul odor pus was rushed out. The 7th and 8th ribs were resected segmentally about 5cm. The abscess cavity was placed in the subphrenic area, therefore the operative fields extended along the 8th ICS. After the evacuation of subphrenic abscess, the granulomatous tissues from the superior aspect of liver was seen. The granuloma was resected and the penrose drainage was inserted. The tuberculosis was resulted from the 8th ICS muscles. subphrenic abscess and granuloma on the pathology report.

• 대한수학회지
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• 제52권5호
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• pp.1003-1021
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• 2015

A matrix completion problem has been exploited amply because of its abundant applications and the analysis of contractions enables us to have insight into structure and space of operators. In this article, we focus on a specific completion problem related to Hankel partial contractions. We provide concrete necessary and sufficient conditions for the existence of completion of Hankel partial contractions for both extremal and non-extremal types with lower dimensional matrices. Moreover, we give a negative answer for the conjecture presented in [8]. For our results, we use several tools such as the Nested Determinants Test (or Choleski's Algorithm), the Moore-Penrose inverse, the Schur product techniques, and a congruence of two positive semi-definite matrices; all these suggest an algorithmic approach to solve the contractive completion problem for general Hankel matrices of size $n{\times}n$ in both types.

• 대한수학회지
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• 제48권1호
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• pp.33-48
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• 2011

The notion of the generalized Fibonacci matrix $\mathcal{F}_n^{(a,b,s)}$ of type s, whose nonzero elements are generalized Fibonacci numbers, is introduced in the paper [23]. Regular case s = 0 is investigated in [23]. In the present article we consider singular case s = -1. Pseudoinverse of the generalized Fibonacci matrix $\mathcal{F}_n^{(a,b,-1)}$ is derived. Correlations between the matrix $\mathcal{F}_n^{(a,b,-1)}$ and the Pascal matrices are considered. Some combinatorial identities involving generalized Fibonacci numbers are derived. A class of test matrices for computing the Moore-Penrose inverse is presented in the last section.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.679-684
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• 1993

This article presents an approach to estimate the general 3D motion of a polyhedral object using multiple, sensory data some of which may not provide sufficient information for the estimation of object motion. Motion can be estimated continuously from each sensor through the analysis of the instantaneous state of an object. We have introduced a method based on Moore-Penrose pseudo-inverse theory to estimate the instantaneous state of an object. A linear feedback estimation algorithm is discussed to estimate the object 3D motion. Then, the motion estimated from each sensor is fused to provide more accurate and reliable information about the motion of an unknown object. The techniques of multisensor data fusion can be categorized into three methods: averaging, decision, and guiding. We present a fusion algorithm which combines averaging and decision.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2008년도 춘계 학술발표회 논문집
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• pp.89-94
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• 2008

This paper deals with the method of self-equilibrium stress mode analysis of cable dome structures. From the point of view of analysis, cable dome structure is a kind of unstable truss structure which is stabilized by means of introduction of prestressing. The prestress must be introduced according to a specific proportion among different structural member and it is determined by an analysis called self-equilibrium stress mode analysis. The mathematical equation involved in the self-equilibrium stress mode analysis is a system of linear equations which can be solved numerically by adopting the concept of Moore-Penrose generalized inverse. The calculation of the generalized inverse is carried out by rank factorization method. This method involves a parameter called epsilon which plays a critical role in self-equilibrium stress mode analysis. It is thus of interest to investigate the range of epsilon which produces consistent solution during the analysis of self-equilibrium stress mode.

• Journal of applied mathematics & informatics
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• 제26권5_6호
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• pp.1011-1020
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• 2008

The problem of finding Cramer rule for solutions of some restricted linear equation Ax = b has been widely discussed. Recently Wang and Qiao consider the following more general problem AXB = D, $R(X){\subset}T$, $N(X){\supset}\tilde{S}$. They present the solution of above general restricted matrix equation by using generalized inverses and give an explicit expression for the elements of the solution matrix for the matrix equation. In this paper we re-consider the restricted matrix equation and give an equivalent matrix equation to it. Through the equivalent matrix equation, we derive condensed Cramer rule for above restricted matrix equation. As an application, condensed determinantal expressions for $A_{T,S}^{(2)}$ A and $AA_{T,S}^{(2)}$ are established. Based on above results, we present a method for computing the solution of a kind of restricted matrix equation.