• 한국정보통신설비학회:학술대회논문집
• /
• 한국정보통신설비학회 2006년도 하계학술대회
• /
• pp.255-258
• /
• 2006

In the H.264/AVC standard, intra prediction increases the coding efficiency of intra macroblocks and by applying rate-distortion optimization to each macroblock, it is possible to choose Inter or Intra encoding adaptively. This sort of encoding scheme, however, increases encoding complexity dramatically and causes troubles in practical applications of the real-time mobile environment. In order to decrease the complexity, variety of methods is proposed but most of those take only its current block into consideration for selecting candidate modes which naturally causes degradation in PSNR (Peak Signal to Noise Ratio). The proposed fast intra mode decision finds the candidate modes by analyzing transformed coefficients of neighboring blocks stored in the buffer at the encoder stage of input sequences. We verify this proposed scheme in complexity, PSNR and bit-rate.

• 대한수학회지
• /
• 제46권2호
• /
• pp.225-236
• /
• 2009

The equicontinuity and scattering properties of continuous semi-flows are studied on a compact metric space. The main results are obtained as follows: first, the complexity function defined by the spanning set is bounded if and only if the system is equicontinuous; secondly, if a continuous semi-flow is topologically weak mixing, then it is pointwise scattering; thirdly, several equivalent conditions for the time-one map of a continuous semi-flow to be scattering are presented; Finally, for a minimal continuous map it is shown that the "non-dense" requirement is unnecessary in the definition of scattering by using open covers.

• 한국멀티미디어학회논문지
• /
• 제21권1호
• /
• pp.18-25
• /
• 2018

In High Efficiency Video Coding (HEVC), integer motion estimation (IME) requires a large amount of computational complexity because HEVC adopts the high flexible and hierarchical coding structures. In order to reduce the computational complexity of IME, this paper proposes the search range reduction algorithm, which takes advantage of motion vectors similarity between different layers. It needs only a few modification for HEVC reference software. Based on the experimental results, the proposed algorithm reduces the processing time of IME by 28.1% on average, whereas its the $Bj{\emptyset}ntegaard$ delta bitrate (BD-BR) increase is 0.15% which is negligible.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제5권8호
• /
• pp.1444-1456
• /
• 2011

This paper presents a low-complexity algorithm for an H.264/AVC encoder. The proposed motion estimation scheme determines the best coding mode for a given macroblock (MB) by finding motion-blurred MBs; identifying, before motion estimation, an early selection of MBs; and hence saving processing time for these MBs. It has been observed that human vision is more sensitive to the movement of well-structured objects than to the movement of randomly structured objects. This study analyzed permissible perceptual distortions and assigned a larger inter-mode value to the regions that are perceptually less sensitive to human vision. Simulation results illustrate that the algorithm can reduce the computational complexity of motion estimation by up to 47.16% while maintaining high compression efficiency.

• 디지털산업정보학회논문지
• /
• 제9권1호
• /
• pp.95-102
• /
• 2013

This paper covers nulling algorithm. In this algorithm, we assume that nulling points are already known. In general, nulling algorithm using matrix equation was utilized. But, this algorithm is pointed out that computational complexity is disadvantage. So, we choose gradient method to reduce the computational complexity. In order to further reduce the computational complexity, we propose approximate gradient method using characteristic of trigonometric functions. The proposed method has same performance compared with conventional method while having half the amount of computation when the number of antenna and nulling point are 20 and 1, respectively. In addition, we could virtually eliminate the trigonometric functions arithmetic. Trigonometric functions arithmetic cause a big problem in actual implementation like FPGA processor(Field Programmable gate array). By utilizing the above algorithm in a multi-cell environment, beamforming gain can be obtained and interference can be reduced at same time. By the above results, the algorithm can show excellent performance in the cell boundary.

• 호남수학학술지
• /
• 제35권2호
• /
• pp.235-249
• /
• 2013

It is well known that each kernel function defines primal-dual interior-point method (IPM). Most of polynomial-time interior-point algorithms for linear optimization (LO) are based on the logarithmic kernel function ([9]). In this paper we define new eligible kernel function and propose a new search direction and proximity function based on this function for LO problems. We show that the new algorithm has $\mathcal{O}(({\log}\;p)^{\frac{5}{2}}\sqrt{n}{\log}\;n\;{\log}\frac{n}{\epsilon})$ and $\mathcal{O}(q^{\frac{3}{2}}({\log}\;p)^3\sqrt{n}{\log}\;\frac{n}{\epsilon})$ iteration complexity for large- and small-update methods, respectively. These are currently the best known complexity results for such methods.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
• /
• pp.171-176
• /
• 1999

Template matching is one of the most often used techniques for machine vision applications to find a template of size M$\times$M or subimage in a scene image of size N$\times$N. Most template matching methods, however, require pixel operations between the template and the image under analysis resulting in high computational cost of O(M2N2). So in this thesis, we present a two stage template matching method. In the first stage, we use a novel low cost feature whose complexity is approaching O(N2) to select matching candidates. In the second stage, we use conventional template matching method to find out the exact matching point. We compare the result with other methods in terms of complexity, efficiency and performance. Proposed method was proved to have constant time complexity and to be quite invariant to noise.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 1998년도 춘계종합학술대회
• /
• pp.342-347
• /
• 1998

병렬 프로그램의 스케줄링 기법에 있어, 타스크 중복 알고리즘은 리스트 스케줄링 알고리즘에 비해 상대적으로 새로운 접근 방식이다. 타스크 중복이란 어떤 프로세서에 할당되어 있는 중요한(critical) 타스크들을 다른 프로세서에 중복시켜, 그 타스크들이 중복 실행하도록 프로그램을 스케쥴하는 것이다. 따라서, 중요한 타스크들이 같은 프로세서내에 있게 되어, 다른 타스크들의 시작 시간(start time)을 줄일 수 있게 된다. 이는 결국 전체 프로그램의 스케줄 길이(schedule length)를 줄이게 된다. 병렬 프로그램의 스케줄링 목적은 프로그램의 스케쥴 길이를 최소화하고, 스케줄의 complexity를 줄이는 것이다 그러나, 스케줄 길이와 complexity는 상호 trade-off 관계이다 본 논문에서는 기존의 중복 알고리즘과 비교하여, 스케쥴 길이를 승가 시키지 않으면서, complexity를 같거나 더 적게하는 알고리즘을 제시하여 컴파일 시간을 향상시키고자 한다.

• 한국IT서비스학회지
• /
• 제5권1호
• /
• pp.191-198
• /
• 2006

Boolean matrices have been successfully used in various areas, and many researches have been performed on them. However, almost all the researches focus on the efficient multiplication of two boolean matrices and no research has been shown to deal with the multiplication of all boolean matrices and their consecutive multiplications. The paper suggests a mathematical theory that enables the efficient consecutive multiplications of all $l{\times}n,\;n{\times}m,\;and\;m{\times}k$ boolean matrices, and discusses its computational complexity and the execution results of the consecutive multiplication algorithm based on the theory.

• 한국IT서비스학회지
• /
• 제6권1호
• /
• pp.151-158
• /
• 2007

D-class computation requires multiplication of three Boolean matrices for each of all possible triples of $n{\times}n$ Boolean matrices and search for equivalent $n{\times}n$ Boolean matrices according to a specific equivalence relation. It is easy to see that even multiplying all $n{\times}n$ Boolean matrices with themselves shows exponential time complexity and D-Class computation was left an unsolved problem due to its computational complexity. The vector-based multiplication theory shows that the multiplication of three Boolean matrices for each of all possible triples of $n{\times}n$ Boolean matrices can be done much more efficiently. However, D-Class computation requires computation of equivalent classes in addition to the efficient multiplication. The paper discusses a theory and an algorithm for efficient D-class computation, and shows execution results of the algorithm.