• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1554-1561
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• 1998

When the superposition of realtime traffic and non-realtime traffic is applied to the ATM network, the successive cell loss(block loss) is more influential on the quality of service (QoS) of two traffic streams than the single loss in case of bursty traffic. Block loss can be identified as an important performance measure because of delay-oriented policy for realtime traffic. In this paper, we consider the system with the two-level overload control reducing of the recurrence of shut-down periods and develop a recursive algorithm to obtain both block loss and cell loss probabilities of both traffic. We can see that it gives the more precise and diverse investigations on performance analysis of queuing strategy.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.924-926
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• 2017

본 논문에서는 좁고 곡률이 큰 도로에서의 자율 주행을 위한 AVM 시스템 기반의 알고리즘을 제안한다. 기존의 전방을 주시하는 모노/스테레오 카메라를 이용한 차선 인식 방법을 이용한 자율주행 알고리즘은 모노/스테레오 카메라의 제한된 FOV (Field of View)로 인해 좁고 곡률이 큰 도로에서의 자율 주행에 한계가 있다. 제안하는 알고리즘은 AVM 시스템을 기반으로 하여 이 한계를 극복하고자 한다. AVM 시스템에서 얻은 영상을 차선의 색상 정보를 이용해 차선의 영역을 이진화 한다. 이진화 영상으로부터, 차량의 뒷바퀴 주변의 관심영역을 시작으로 재귀적 탐색법을 이용하여 좌, 우 차선을 검출한다. 검출된 좌, 우 차선의 중앙선을 차량의 경로로 삼고 조향각을 산출해 낸다. 제한하는 알고리즘을 실제 차량에 적용시킨 실험을 수행하였고, 운전면허 시험장의 코스를 차선의 이탈없이 주행 가능함을 실험적으로 확인하였다.

• The Transactions of the Korea Information Processing Society
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• v.5 no.3
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• pp.833-841
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• 1998

The ann of this study is 10 propose all eff'tcient mclhod for partition of multi-dimensIOnal feature space into pattern subspace for automated generation of fuzzy rule. The suggested mclhod predicates on sequential subdivision of the fuzzy subspacc. and the size of construc1cd pattern space is variable. Under this procedure, n-dimensional pattern space, after considering the distributional characteristic patterns, is partitioned into two different pattern subspaces. From the two subspaces, the pattern space for further subdivision is chosen; then, this subdivision procedure recursively repeats itself until the stopping condition is fulfilled. The result of this study is applied to 2, 4, 7 band of satellite Landsat TM and satisfac10ry result is acquired.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06b
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• pp.182-187
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• 2007

본 논문에서는 이미지 상에 나타난 색상 정보를 추출하기 위한 새로운 커널 메소드(Kernel method)인 Grid kernel을 제안한다. 제안한 Grid kernel은 Convolution kernel의 하나로 이미지 상에 나타나는 자질을 주변 픽셀에서 나타나는 자질로 정의 하고 이를 재귀적으로 적용함으로써 두 이미지를 비교한다. 본 논문에서는 제안한 커널을 차량 색상 인식 문제에 적용하여 차량 색상 인식 모델을 제안한다. 이미지 생성시 나타나는 주변 요인으로 인해 차량의 색상을 추출하는 것은 어려운 문제이다. 이미지가 야외에서 촬영되기 때문에 시간, 날씨 등의 주변 요인은 같은 차량이라 하더라도 다른 색상을 보이게 할 수 있다. 이를 해결하기 위해 Grid kernel이 적용된 차량 색상 인식 모델은 이미지를 HSV (Hue-Saturation-Value) 색상 공간으로 사상하여 명도를 배제하였다. 제안한 커널과 색상 인식 모델을 검증하기 위해 5가지 색상을 가진 차량 이미지를 이용하여 실험을 하였으며, 실험 결과 92.4%의 정확율과 92.0%의 재현율을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10C
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• pp.1000-1010
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• 2006

This paper proposes a new architecture for DCT-based motion estimation and compensation. Previous methods do riot take sufficient advantage of the sparseness of 2-D DCT coefficients to reduce execution time. We first derive a recursion equation to perform DCT domain motion estimation more efficiently; we then use it to develop a wavefront array processor (WAP) consisting of processing elements. In addition, we show that the recursion equation enables motion predicted images with different frequency bands, for example, from the images with low frequency components to the images with low and high frequency components. The wavefront way Processor can reconfigure to different motion estimation algorithms, such as logarithmic search and three step search, without architectural modifications. These properties can be effectively used to reduce the energy required for video encoding and decoding. The proposed WAP architecture achieves a significant reduction in computational complexity and processing time. It is also shown that the motion estimation algorithm in the transform domain using SAD (Sum of Absolute Differences) matching criterion maximizes PSNR and the compression ratio for the practical video coding applications when compared to tile motion estimation algorithm in the spatial domain using either SAD or SSD.

• Journal of Broadcast Engineering
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• v.24 no.4
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• pp.633-642
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• 2019

Recently, the convolution neural network (CNN) model at a single image super-resolution (SISR) have been very successful. The residual learning method can improve training stability and network performance in CNN. In this paper, we propose a SISR using recursive residual network architecture by introducing dense skip connections for learning nonlinear mapping from low-resolution input image to high-resolution target image. The proposed SISR method adopts a method of the recursive residual learning to mitigate the difficulty of the deep network training and remove unnecessary modules for easier to optimize in CNN layers because of the concise and compact recursive network via dense skip connection method. The proposed method not only alleviates the vanishing-gradient problem of a very deep network, but also get the outstanding performance with low complexity of neural network, which allows the neural network to perform training, thereby exhibiting improved performance of SISR method.

• The Journal of the Acoustical Society of Korea
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• v.27 no.5
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• pp.256-261
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• 2008

In this paper, we propose a novel approach to improve the performance of minima controlled recursive averaging (MCRA) which is based on the conditional maximum a posteriori criterion. A crucial component of a practical speech enhancement system is the estimation of the noise power spectrum. One state-of-the-art approach is the minima controlled recursive averaging (MCRA) technique. The noise estimate in the MCRA technique is obtained by averaging past spectral power values based on a smoothing parameter that is adjusted by the signal presence probability in frequency subbands. We improve the MCRA using the speech presence probability which is the a posteriori probability conditioned on both the current observation the speech presence or absence of the previous frame. With the performance criteria of the ITU-T P.862 perceptual evaluation of speech quality (PESQ) and subjective evaluation of speech quality, we show that the proposed algorithm yields better results compared to the conventional MCRA-based scheme.

• The KIPS Transactions:PartB
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• v.13B no.2 s.105
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• pp.127-132
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• 2006

K-NN (k-Nearest Neighbors), which is a well-known instance-based learning algorithm, simply stores entire training patterns in memory, and uses a distance function to classify a test pattern. K-NN is proven to show satisfactory performance, but it is notorious formemory usage and lengthy computation. Various studies have been found in the literature in order to minimize memory usage and computation time, and NGE (Nested Generalized Exemplar) theory is one of them. In this paper, we propose RPA (Recursive Partition Averaging) and IRPA (Incremental RPA) which is an incremental version of RPA. RPA partitions the entire pattern space recursively, and generates representatives from each partition. Also, due to the fact that RPA is prone to produce excessive number of partitions as the number of features in a pattern increases, we present IRPA which reduces the number of representative patterns by processing the training set in an incremental manner. Our proposed methods have been successfully shown to exhibit comparable performance to k-NN with a lot less number of patterns and better result than EACH system which implements the NGE theory.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.11b
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• pp.224-228
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• 2002

DRM(Distal Right Management)은 컨텐츠의 불법 사용을 방지하여 저작권을 보호하고, 컨턴츠의 생성·유통·사용 관리 등에 필요한 모든 처리를 지원하는 종합 솔루션이다. DRM 체계에서 사용자(customer)는 컨텐츠를 정당하게 사용하기 위해서 클리어링하우스(clrearinghouse)로부터 라이센스를 발급받아야 한다. 일반적으로 라이센스(license)는 사용자의 공개키로 암호화된다. 그래서 사용자의 계산적 부담이 크다. 특히 무선 DRM 환경이라면, 사용자의 부담은 더 클 것이다. 따라서 본 논문은 익명성을 갖는 제안 1회용 대리서명 기법과 Y.Zheng의 Singcryption 기법을 적용하여 사용자의 계산량을 줄이고, 익명성을 갖는 효율적인 라이센스 다운로드 방식을 제안한다.

• Journal of Korea Multimedia Society
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• v.15 no.3
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• pp.398-407
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• 2012

We propose a tree modeling method of expressing realistically and efficiently numerous trees distributed on a broad terrain. This method combines and simplifies the recursive hierarchy of tree branch and branch generation process through self-organizing from buds, allowing users to generate trees that can be used more intuitively and efficiently. With the generation process the leveled structure and the appearance such as branch length, distribution and direction can be controlled interactively by user. In addition, we introduce an environment-adaptive model that allows to grow a number of trees variously by controlling at the same time and we propose an efficient application method of growing environment. For the real-time rendering of the complex tree models distributed on a broad terrain, the rendering process, the LOD(level of detail) for the branch surfaces, and shader instancing are introduced through the GPU(Graphics Processing Unit). Whether the numerous trees are expressed realistically and efficiently on wide terrain by proposed models are confirmed through simulation.