• 한국음향학회지
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• 제26권2호
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• pp.69-74
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• 2007

입력신호의 상관도가 높은 신호처리 응용에서 부밴드 인접투사(Subband Affine Projection: SAP) 알고리즘과 스텝사이즈 조정은 LMS형(Least Mean Square-type) 알고리즘이 갖는 느린 수렴속도와 큰 정상상태오차를 개선할 수 있는 좋은 해결책이다. 본 논문은 가변 스텝사이즈를 사용하는 부밴드 인접투사 알고리즘을 제안한다. 제안한 방법은 부밴드 구조의 인접투사 알고리즘과 스텝사이즈 조정을 결합함으로써 적은 계산량으로 빠른 수렴속도와 작은 정상상태오차를 얻을 수 있다. 높은 상관도를 갖는 입력신호에 대한 실험을 통해 제안한 방법이 기존 방법에 비해 우수함을 보인다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2004년도 춘계학술대회 학술발표 논문집 제14권 제1호
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• pp.133-136
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• 2004

This paper proposes a stability condition in affine Takagi-Sugeno (T-S) fuzzy systems with parametric uncertainties and then, introduces the design method of a fuzzy-model-based controller which guarantees the stability. The analysis is based on Lyapunov functions that are continuous and piecewise quadratic. The search for a piecewise quadratic Lyapunov function can be represented in terms of linear matrix inequalities (LMIs).

• 전자공학회논문지CI
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• 제48권2호
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• pp.55-65
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• 2011

본 논문은 증강현실 시스템에서 마커가 가려진 상황에서도 강건한 마커 검출을 위하여 지역적인 특징 점들을 이용하는 방법을 제안한다. 가려진 마커를 효율적으로 검출하기 위하여, 첫 번째 단계로 등록된 마커와 가려진 마커가 포함된 입력 영상을 Affine-SIFT (ASIFT, Affine-Scale Invariant Features Transform) 방법을 이용해 정합된 특징 점들을 검출한다. 두 번째 단계로 정합된 특징 점들의 이상치(Outlier)를 제거하기 위하여, 등록된 마커의 특징 점들에 주성분 분석(Principal Component Analysis)을 적용하고 제 1 주축과 제 2 주축으로 사영한 후 중심으로 부터의 거리에 대한 평균값을 타원의 장축과 단축으로 지정한다. 세 번째 단계로 마커의 기하학적인 왜곡을 추정하기 위하여 특징 점들이 이루는 Convex-hull 지점들을 다각형의 꼭짓점으로 정한다. 마지막 단계로, 입력영상에 정합된 특징 점들의 기하적인 왜곡의 변화를 추정함으로써 마커의 가려진 환경에 서도 강건한 마커 검출 결과를 얻을 수 있다.

• 제어로봇시스템학회논문지
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• 제6권8호
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• pp.727-731
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• 2000

This paper presents a new practical autopilot design approach to acceleration control for tail-controlled STT(Skid-to-Turn) missiles. The approach is novel in that the proposed parametric affine missile model adopts acceleration as th controlled output and considers the couplings between the forces as well as the moments and control fin deflections. The aerodynamic coefficients in the proposed model are expressed in a closed form with fittable parameters over the whole operating range. The parameters are fitted from aerodynamic coefficient look-up tables by the function approximation technique which is based on the combination of local parametric models through curve fitting using the corresponding influence functions. In this paper in order to employ the results of parametric affine modeling in the autopilot controller design we derived a parametric affine missile model and designed a feedback linearizing controller for the obtained model. Stability analysis for the overall closed loop sys-tem is provided considering the uncertainties arising from approximation errors. the validity of the proposed modeling and control approach is demonstrated through simulations for an STT missile.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.658-662
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• 2004

This paper develops a stability analysis and controller synthesis methodology for a continuous-time affine Takagi-Sugeno (T-S) fuzzy systems with parametric uncertainties. Affine T-S fuzzy system can be an advantage because it may be able to approximate nonlinear functions to high accuracy with fewer rules than the homogeneous T-S fuzzy systems with linear consequents only. The analysis is based on Lyapunov functions that are continuous and piecewise quadratic. The search for a piecewise quadratic Lyapunov function can be represented in terms of bilinear matrix inequalities (BMIs). A simulation example is given to illustrate the application of the proposed method.

• IEIE Transactions on Smart Processing and Computing
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• 제1권2호
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• pp.78-87
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• 2012

In this paper, we address the tracking problem caused by camera motion and rolling shutter effects associated with CMOS sensors in consumer handheld cameras, such as mobile cameras, digital cameras, and digital camcorders. A modified particle filtering method is proposed for simultaneously tracking objects and compensating for the effects of camera motion. The proposed method uses an elastic registration algorithm (ER) that considers the global affine motion as well as the brightness and contrast between images, assuming that camera motion results in an affine transform of the image between two successive frames. By assuming that the camera motion is modeled globally by an affine transform, only the global affine model instead of the local model was considered. Only the brightness parameter was used in intensity variation. The contrast parameters used in the original ER algorithm were ignored because the change in illumination is small enough between temporally adjacent frames. The proposed particle filtering consists of the following four steps: (i) prediction step, (ii) compensating prediction state error based on camera motion estimation, (iii) update step and (iv) re-sampling step. A larger number of particles are needed when camera motion generates a prediction state error of an object at the prediction step. The proposed method robustly tracks the object of interest by compensating for the prediction state error using the affine motion model estimated from ER. Experimental results show that the proposed method outperforms the conventional particle filter, and can track moving objects robustly in consumer handheld imaging devices.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권6호
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• pp.1253-1272
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• 2010

In this paper, we propose a new affine shape adaptation scheme for the affine invariant feature detector, in which the convergence stability is still an opening problem. This paper examines the relation between the integration scale matrix of next iteration and the current second moment matrix and finds that the convergence stability of the method can be improved by adjusting the relation between the two matrices instead of keeping them always proportional as proposed by previous methods. By estimating and updating the shape of the integration kernel and differentiation kernel in each iteration based on the anisotropy of the current second moment matrix, we propose a coarse-to-fine affine shape adaptation scheme which is able to adjust the pace of convergence and enable the process to converge smoothly. The feature matching experiments demonstrate that the proposed approach obtains an improvement in convergence ratio and repeatability compared with the current schemes with relatively fixed integration kernel.

• 대한전기학회논문지:전력기술부문A
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• 제55권3호
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• pp.133-138
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• 2006

This paper presents an Optimal Power Flow (OPF) algorithm using Interior Point Method (IPM) to swiftly and precisely perform the five minute dispatch. This newly suggested methodology is based on Affine Scaling Interior Point Method which is favorable for large-scale problems involving many constraints. It is also eligible for OPF problems in order to improve the calculation speed and the preciseness of its resultant solutions. Big-M Method is also used to improve the solution stability. Finally, this paper provides relevant case studies to confirm the efficiency of the proposed methodology.

• 한국해안해양공학회지
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• 제16권1호
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• pp.10-17
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• 2004

지본 연구에서는 장기해안선변화를 조사, 해석함에 있어서 정사사진해석에 비해 비교적 손쉬운 affine 변환 해석방법을 이용하여 항공사진 자료를 분석하고, 정확도 평가를 수행하였다. 검토결과, 대상해안은 과거에 비해 해안선이 현저히 후퇴하여 침식되고 있음을 확인할 수 있었다. 또한, 정확도 평가 분석에서 나타난 RMS 오차는 1∼2m 미만의 오차에 불과하다는 것이 확인되었다. 항공사진측량작업내규에서 제시하는 최대허용오차범위가 2m인 점을 감안한다면, 본 연구에서 도출된 해안선변화 분석결과는 신뢰성이 높은 것이라 사료된다.

• 대한수학회지
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• 제36권1호
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• pp.193-207
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• 1999

Let ${\gamma}$ : Ilongrightarrow R2 be a sufficiently smooth curve and $\sigma$${\gamma}$ be the affine arclength measure supported on ${\gamma}$. In this paper, we study the Lp - improving properties of the convolution operators T$\sigma$${\gamma}$ associated with $\sigma$${\gamma}$ for various curves ${\gamma}$. Optimal results are obtained for all finite type plane curves and homogeneous curves (possibly blowing up at the origin). As an attempt to extend this result to infinitely flat curves we give and example of a family of flat curves whose affine arclength measure has same Lp-improvement property. All of these results will be based on uniform estimates of damping oscillatory integrals.