• ETRI Journal
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• 제32권3호
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• pp.351-361
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• 2010

Multiple rotation-based transformation (MRBT) was introduced recently for mitigating the apriori-knowledge independent component analysis (AK-ICA) attack on rotation-based transformation (RBT), which is used for privacy-preserving data clustering. MRBT is shown to mitigate the AK-ICA attack but at the expense of data utility by not enabling conventional clustering. In this paper, we extend the MRBT scheme and introduce an augmented rotation-based transformation (ARBT) scheme that utilizes linearity of transformation and that both mitigates the AK-ICA attack and enables conventional clustering on data subsets transformed using the MRBT. In order to demonstrate the computational feasibility aspect of ARBT along with RBT and MRBT, we develop a toolkit and use it to empirically compare the different schemes of privacy-preserving data clustering based on data transformation in terms of their overhead and privacy.

• ETRI Journal
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• 제30권6호
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• pp.868-870
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• 2008

The rotation-based transformation (RBT) for privacy preserving data mining is vulnerable to the independent component analysis (ICA) attack. This paper introduces a modified multiple-rotation-based transformation technique for special mining applications, mitigating the ICA attack while maintaining the advantages of the RBT.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.939-944
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• 1990

To recognize isomorphic transformation patterns, such as scale-change, translation and rotation transformed patterns, is an old difficult but interesting problem. Many researches have been done with a dominant approach of normalization by many eminent pioneers. However, there seems no a perfect system which can even recognize 90 .deg.-multiple rotation isomorphic transformation patterns for real needs. Here, as a new challenge, we propose a method of how to recognize 90 .deg.-multiple rotation isomorphic and symmetry isomorphic transformation patterns.

• 전자공학회논문지S
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• 제34S권12호
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• pp.98-105
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• 1997

Image transformation ahs been widely used in compuater graphics, computer vision, robot vision, and image processing. Image rotation is one of important part of image transformation. In image rotation, a two-pass algorithm has many advantages over a one-pass algorithm in high speed computation. This paper presents a new two-pass algorithm that overcomes the limitations of previously reported effect of interpolation. A brief comparison of existent techniques and the twp-pass algorithm newly suggeste is presented. This paper also present the hardware structure for the two-pass algorithm suggested.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제4권10호
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• pp.431-438
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• 2015

본 논문에서는 대칭 변환을 지원하는 윤곽선 이미지 매칭 문제를 다룬다. 이미지 매칭에서 이미지의 대칭 변환을 지원하는 것은 직관적이고 정확한 매칭을 위한 매우 중요한 요소이다. 그러나 기존 이미지 매칭에서는 이미지의 회전 변환만 고려하였을 뿐 대칭 변환은 고려하지 않았다. 본 논문에서는 기존 회전-불변 윤곽선 이미지 매칭에 대칭 변환까지 지원하는 대칭-불변 윤곽선 이미지 매칭을 제안한다. 이를 위해, 먼저 이미지 대칭의 개념을 정의하고, 어떠한 대칭각을 사용하더라도 회전-불변 매칭의 결과는 동일함을 정형적으로 증명한다. 또한, 대칭 변환을 위해 이미지 윤곽선으로부터 대칭 시계열을 효율적으로 추출하는 방법을 제안한다. 그런 다음, 이미지를 대칭하여 생성한 대칭 시계열과 원본 이미지 시계열을 직접 대칭하여 생성한 대칭 시계열을 사용한 회전-불변 매칭 결과가 동일함을 정형적으로 증명한다. 실험 결과, 제안하는 대칭-불변 윤곽선 이미지 매칭은 회전 변환만을 지원하는 기존 이미지 매칭에 비해 보다 정확하고 직관적인 결과를 도출하는 것으로 나타났다. 이같은 결과는 대칭-불변 윤곽선 이미지 매칭이 이미지의 대칭 변환 문제를 시계열 도메인에서 해결한 우수한 해결책임을 의미한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.448-451
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• 1988

This paper deals with the rotation-free optical sensor which will be used for two dimensional robot tracking. This sensor consists of position sensing device and coordinate transformation unit which transform the sensor coordinate into base coordinate. A new coordinate transformation algorithm which use analog signal is presented, and an analog circuit based on this algorithm is constructed. To prove the rightness of this algorithm, same experiments are carried out. And the performance, of this sensor is investigated.

• Journal of electromagnetic engineering and science
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• 제4권3호
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• pp.102-106
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• 2004

A novel Genetic Algorithm(GA)-based method is suggested to transform a coupling matrix to another, without the procedure of Matrix Rotation. This can remove tedious work like pivoting and deciding rotation angles needed for each of the iterations. The error function for the GA is simply formed and used as part of error minimization for obtaining the solution. An 8th order dual-mode elliptic integral function response filter is taken as an example to validate the present method.

• 한국운동역학회지
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• 제21권4호
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• pp.449-458
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• 2011

There are many functional methods for estimating the mean axis of rotation of a joint. However, it is still a controversial issue which method is superior. The purpose of this study was to compare functional methods for estimated axes of rotation from synthetic data. The comparison was made in terms of suitabilities on describing humans in sports. For a more practical situation, the axis error as well as measurement and marker movement error were applied to generated data. Simulations having 1000 times of 80 rotational displacements were performed. The functional methods used in the study were two transformation methods, two fitting methods, and one more transformation method called M. The M method is a combination of S$\ddot{o}$derk & Wedin(1993) and Mardia & Jupp(2000). Another factor of the study was angular velocity with levels of .01, .025, .05, .5 and 1 rad/s. The method M resulted in unbiased, stable, and consistent axis of rotation vectors in all levels of angular velocity except .01 rad/s. Therefore, the method M had the highest validity and reliability of all the methods. The fitting methods were very sensitive in small angular velocities and stable only in the velocities of more than .5 rad/s. The most suitable method for analyzing human motion by using marker photogrammetry is M.

• 한국군사과학기술학회지
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• 제12권3호
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• pp.368-377
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• 2009

In this paper we study the gyro bias calibration method of SDINS(Strap-Down Inertial Navigation System). Generally, SDINS's calibration is performed in 2-axis(or 3-axis) rate table with chamber for varying ambient temperature. We assumed that the majority of calibration-parameter except for gyro bias is knowned. During gyrobias calibration procedure, it can be induced some disturbances(accelerometer's short-term error induced rate table rotation and anti-vibration mount's rotation). In these cases, old gyro-bias calibration methods(using velocity error or attitude error) have an error, because these disturbances are not detectable at the same time. So that, we propose a new gyro-bias calibration method(heading error minimizing using equivalent linear transformation) that can detect anti-vibration mount's rotation. And we confirm efficiency of the new gyro-bias calibration method by simulation.

• 한국전자파학회논문지
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• 제14권6호
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• pp.599-605
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• 2003

이중모드 비대칭 canonical 구조 필터는 일반적으로 위성 중계기의 입력 멀티플렉서에 주로 사용된다. 본 논문에서는 비대칭형 canonical 필터의 용이한 합성 방법에 대하여 언급하였다. 비대칭형 canonical 필터의 결합행렬은 대칭형 canonical 필터의 결합 행렬로부터 평면 회전(plane rotation)과 같은 similarity transformation을 이용하여 구하였다. 비대칭형 canonical 필터의 결합 행렬을 구하기 위한 similarity transformation 과정에 있어서 회전 순서, 피벗(pivot), 회전각을 제시하였다. 본 논문에서 제시한 방법을 이용하여 8차 및 10차 비대칭 canonical filter의 결합 행렬을 추출하였으며, 비대칭형 canonical 필터의 주파수 응답 특성은 대칭형 canonical 필터의 주파수 응답 특성과 동일한 특성을 나타내었다.