• Structural Engineering and Mechanics
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• 제22권5호
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• pp.599-611
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• 2006

The theory with hierarchical warping functions had been used to analyze composite thin-walled structure, laminated beam and had good results. In the present paper, a series of hierarchical warping functions are developed to analyze the cylindrical bending problems of composite lamina. These warping functions which refine through-the-thickness variation of displacements were composed of basic and corrective functions by taking into account of anisotropic, material discontinues, and transverse shear and normal strain. Then the hierarchical finite element method was used to form a numerical algorithm. The distribution of the displacements, in-plane stresses, transverse shear stresses and transverse normal stress for composite laminate were analyzed with the present model. The results show that the present model has precise mechanical response compared with the first deformation transverse theory and the corrective order affects the accuracy of result.

• Korean Journal of Mathematics
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• 제27권4호
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• pp.1133-1147
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• 2019

In this paper, let M = B×_f² F be an Einstein Lorentzian warped product manifold with 2-dimensional base. We study the geodesic completeness of some metric with constant curvature. First of all, we discuss the existence of nonconstant warping functions on M. As the results, we have some metric g admits nonconstant warping functions f. Finally, we consider the geodesic completeness on M.

• 호남수학학술지
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• 제36권3호
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• pp.597-603
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• 2014

In this paper, we prove the existence of warping functions on Riemannian warped product manifolds with fiber manifold of class (B) having some prescribed scalar curvatures.

• 충청수학회지
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• 제28권4호
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• pp.591-602
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• 2015

In this paper, we prove the existence and the nonexistence of warping functions on Riemannian warped product manifolds with some prescribed scalar curvatures according to the fiber manifolds of class (A).

• 호남수학학술지
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• 제40권3호
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• pp.447-456
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• 2018

In this paper, we consider nonconstant warping functions on Einstein Lorentzian warped product manifolds $M=B{\times}_{f^2}F$ with an 1-dimensional base B which has a negative definite metric. As the results, we discuss that on M the resulting Einstein Lorentzian warped product metric is a future (or past) geodesically complete one outside a compact set.

• 산업기술연구
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• 제21권A호
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• pp.167-179
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• 2001

This paper discusses an index-based subsequence matching that supports time warping in large sequence databases. Time warping enables finding sequences with similar patterns even when they are of different lengths. In earlier work, we suggested an efficient method for whole matching under time warping. This method constructs a multidimensional index on a set of feature vectors, which are invariant to time warping, from data sequences. For filtering at feature space, it also applies a lower-bound function, which consistently underestimates the time warping distance as well as satisfies the triangular inequality. In this paper, we incorporate the prefix-querying approach based on sliding windows into the earlier approach. For indexing, we extract a feature vector from every subsequence inside a sliding window and construct a multi-dimensional index using a feature vector as indexing attributes. For query precessing, we perform a series of index searches using the feature vectors of qualifying query prefixes. Our approach provides effective and scalable subsequence matching even with a large volume of a database. We also prove that our approach does not incur false dismissal. To verily the superiority of our method, we perform extensive experiments. The results reseal that our method achieves significant speedup with real-world S&P 500 stock data and with very large synthetic data.

• 한국지능시스템학회논문지
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• 제11권6호
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• pp.563-567
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• 2001

We generalize the widebane P0-weyl symbol (P0WS) and the widebane spreading function (WSF) using the generalized warping function . The new generalized P0WS and WSF are useful for analyzing system and communication channels producing generalized time shifts. We also investigated the relationship between the affine Wey1 symbol(AWS) and the P0WS. By using specific warping functions, we derive new P0WS and WSF as analysis tools for systems and communication channels with non-linear group delary characteristics. The new P0WS preserves specific types of changes imposed on random processes. The new WSF provides a new interpretation of output of system and communication channel as weighted superpositions of non-linear time shifts on the input. It is compared to the conventional method obtaining output of system and communication channel as a convention integration of the input with the impulse response of the system and the communication channel. The convolution integration can be interpreted as weighted superpositions of liner time shifts on the input where the weight is the impulse response of the system and the communication channel. Application examples in analysis and detection demonstrate the advantages of our new results.

• 대한전자공학회논문지SD
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• 제43권6호
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• pp.23-29
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• 2006

본 논문에서는 Quadratic Programming(QP)을 이용한 효과적인 광역배치 기법을 제안한다. QP를 이용한 배치 기법의 단점인 셀 밀집 문제를 해결하기 위해 추가적인 힘(additional force)과 Grid Pre-warping 기법을 사용하였다 추가적인 힘은 밀집도에 기반한 값으로 적절한 힘을 구하기 위해 새로운 밀집도 함수를 고안하였다. Grid Pre-warping은 셀 좌표 사이의 상대적인 순서에 따라 셀들을 전체 영역에 재배치하는 기법이다. 새로운 밀집도 함수를 통해 구해진 추가적인 힘과 Pre-warping 기법을 반복적으로 적용하여 셀들이 효과적으로 분산된 광역배치를 얻었다. 이렇게 얻어진 배치를 "middle-down" 방식의 배치기인 Mongre의 초기배치로 적용하여 최종 상세배치 결과를 얻었다 제안하는 기법을 적용한 실험결과, FM 기법을 이용한 광역배치에 비해 향상된 결과를 보였으며, 우수한 배치기로 알려진 FengShui, Dragon과도 비교할만한 결과를 얻었다.

• 정보처리학회논문지D
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• 제13D권3호
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• pp.357-368
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• 2006

본 논문에서는 타임 워핑 하의 시계열 서브시퀀스 매칭을 처리하는 방법에 대하여 논의한다. 타임 워핑은 시퀀스의 길이가 서로 다른 경우에도 유사한 패턴을 갖는 시퀀스들을 찾을 수 있도록 해 주는 변환이다. 접두어 질의 기법(prefix-querying method)는 착오 기각 없이 타임 워핑 하의 시계열 서브시퀀스 매칭을 처리하는 인덱스를 이용한 최초의 방식이다. 이 방법은 사용자가 질의를 편리하게 작성하도록 하기 위하여 기본 거리함수로서 $L_{\infty}$를 사용한다. 본 논문에서는 $L_{\infty}$ 대신 타임 워핑 하의 시계열 서브시퀀스 매칭에서 기본 거리 함수로서 가장 널리 사용되는 $L_1$을 적용할 수 있도록 접두어 질의를 확장한다. 또한, 제안된 기법으로 타임 워핑 하의 시계열 서브시퀀스 매칭을 수행하는 경우 착오 기각(false dismissal)이 발생하지 않음을 이론적으로 증명한다. 다양한 실험을 통한 성능 평가를 통하여 본 연구에서 제시하는 기법의 우수성을 검증한다. 실험 결과에 의하면, 제안된 기법은 가장 좋은 성능을 보이는 기존의 기법과 비교하여 매우 뛰어난 성능 개선 효과를 보이는 것으로 나타났다.

• 한국자동차공학회논문집
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• 제13권3호
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• pp.146-153
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• 2005

Structural design of the torsion beam rear suspension is investigated by calculating warping of the torsion beam. Since the longitudinal displacement in the cross section of the torsion beam due to torsional moment causes normal stress across the beam restrained from outside at both ends, the profile of torsion beam needs to be designed considering the warping. Warping function of the beam is derived with the parameters of cross section fur the arbitrary shapes of torsion beam profiles assuming thin-walled open section. From comparing the warping calculated for two different beam profiles, the design method for the torsion beam in the view point of low stress is discussed. It is shown that the gusset used to reinforce the torsion beam can be optimized in accordance with warping shape. The method to fix the end point of the gusset is proposed to minimize the stress concentrated on the end point of the gusset produced during torsional moment. The result from finite element analysis shows the stress is minimized when the height of gusset end point is coincident with the point where warping of the beam is minimized.