• 정보교육학회논문지
• /
• 제2권2호
• /
• pp.260-268
• /
• 1998

본 연구에서는 HTML이나 XML로 작성한 Web 문서들의 복잡도를 측정하는 모델을 제안한다, 문서들의 복잡도는 문서들을 이해하는 데 밀접한 영향을 미치고, 이 이해도가 높은 Web 문서들은 결국 WEI에 좋은 효과를 거둘 수 있다. 본 연구에서 제안한 복잡도는 Web 문서들 간의 주고받는 정보의 흐름의 정도를 표현하기 위하여 엔트로피의 함수를 이용한다. 제안한 문서 복잡도는 문서들간의 정보 이동 관계에 의해서 문서들 내의 정보 흐름을 측정한다. 논 연구에서 제안한 문서 복잡도의 타당도는 Weyuker가 제안한 프로그램의 복잡도 평가 방법을 이용하여 평가하였고, 실제 문서들의 복잡도를 측정하였다. 또한 문서화일의 수와 문서 복잡도간의 상관관계를 분석하여 본 연구에서 제안한 문서 복잡도의 효율성을 제시하였다.

• 한국컴퓨터정보학회논문지
• /
• 제15권8호
• /
• pp.117-126
• /
• 2010

소프트웨어 복잡도는 대상 시스템의 유지보수성을 평가하는 주요한 메트릭인데 기존의 웹 어플리케이션 기반 복잡도는 대부분 단순히 개수 기반으로 정의되어 실제 개발자나 유지보수자의 관점에서 느끼는 이해도를 반영하기 어렵다. 이를 보완하기 위하여 정보이론의 엔트로피를 이용하여 복잡도를 정의할 수 있으나, 개별 페이지의 정보량을 동일하게 취급하고 있다. 본 논문에서는 웹 어플리케이션의 구조 복잡도를 유사도 및 정보이론에 기반하여 제안하였다. 즉, 엔트로피에 기반하되, 기존의 유사도를 이용하여 타 페이지들과 유사성이 높은 페이지의 내부 정보량은 그렇지 않은 페이지보다 낮도록 정의하여 이러한 단점을 보완하였다. 또한 관점에 따라 각기 다른 유사도를 적용할 수 있도록 함으로써 복잡도를 여러 관점에서 측정할 수 있도록 하였다. 이후 복잡도 속성을 이용하여 이론적으로 검증하였고, 사례 연구를 통하여 본 기법의 유용성을 보였다.

• The Journal of the Acoustical Society of Korea
• /
• 제17권3E호
• /
• pp.53-57
• /
• 1998

Spectral information at a speech coder should be quantized with sufficient accuracy to keep perceptually transparent output speech. Spectral information at a low bit rate speech coder is usually transformed into corresponding line spectrum pair parameters and is often quantized with a vector quantization algorithm. As the vector quantization algorithm generally has high complexity in the optimal code vector searching routine, the complexity reduction in that routine is investigated using the ordering property of the line spectrum pair. When the proposed complexity reduction algorithm is applied to the well-known split vector quantization algorithm, the 46% complexity reduction is achieved in the distortion measure compu-tation.

• 대한수학회지
• /
• 제45권1호
• /
• pp.221-228
• /
• 2008

In this paper, we study the complexity of semigroup actions using complexity functions of open covers. The main results are as follows: (1) A dynamical system is equicontinuous if and only if any open cover has bounded complexity; (2) Weak-mixing implies scattering; (3) We get a criterion for the scattering property.

• Asia pacific journal of information systems
• /
• 제11권2호
• /
• pp.141-158
• /
• 2001

This paper examines the effects of environmental uncertainty, structural decentralization, formalization, complexity and task interdependence on the information sharing through information system. 197 firms in Korea are surveyed and analyzed to investigate the relationship between the contextual variables and the information sharing. The result of multiple regression analysis shows that task interdependence, structural decentralization, complexity are significant factors to influence on the Information Sharing. Also, additional analysis shows that task interdependence, structural decentralization are major factors in service industry, and task interdependence, structural complexity are in manufacturing industry.

• Journal of applied mathematics & informatics
• /
• 제9권2호
• /
• pp.607-620
• /
• 2002

In this paper, we consider the updating problems to reconstruct the biconnected-components and to reconstruct the weighted shortest path in response to the topology change of the network. We propose two distributed algorithms. The first algorithm solves the updating problem that reconstructs the biconnected-components after the several processors and links are added and deleted. Its bit complexity is O((n'+a+d)log n'), its message complexity is O(n'+a+d), the ideal time complexity is O(n'), and the space complexity is O(e long n+e' log n'). The second algorithm solves the updating problem that reconstructs the weighted shortest path. Its message complexity and ideal-time complexity are $O(u^2+a+n')$ respectively.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2006년도 하계종합학술대회
• /
• pp.533-534
• /
• 2006

This paper presents the architecture design of a high-speed, low-complexity 128-point radix-$2^4$ FFT processor for ultra-wideband (UWB) systems. The proposed high-speed, low-complexity FFT architecture can provide a higher throughput rate and low hardware complexity by using 2-parallel data-path scheme and single-path delay-feedback (SDF) structure. This paper presents the key ideas applied to the design of high-speed, low-complexity FFT processor, especially that for achieving high throughput rate and reducing hardware complexity. The proposed FFT processor has been designed and implemented with the 0.18-m CMOS technology in a supply voltage of 1.8 V. The throughput rate of proposed FFT processor is up to 1 Gsample/s while it requires much smaller hardware complexity.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권9호
• /
• pp.4372-4389
• /
• 2019

Spectrum sensing has attracted much attention due to its significant contribution to idle spectrum detection in Cognitive Radio Networks. However, specialized discussion is on complexity-based sensing strategy for spectrum sensing seldom considered. Motivated by this, this paper is devoted to complexity-based sensing strategy for spectrum sensing. Firstly, three efficiency functions are defined to estimate sensing efficiency of a spectrum scheme. Then a novel sensing strategy is proposed given sensing performance and computational complexity. After that, the proposed sensing strategy is extended to energy detector, Cyclostationary feature detector, covariance matrix detector and cooperative spectrum detector. The proposed sensing strategy provides a novel insight into sensing performance estimation for its consideration of both sensing capacity and sensing complexity. Simulations analyze three efficiency functions and optimal sensing strategy of energy detector, Cyclostationary feature detector and covariance matrix detector.

• Journal of Electrical Engineering and Technology
• /
• 제11권4호
• /
• pp.1020-1026
• /
• 2016

Motion estimation (ME) algorithms supporting quarter-pixel accuracy have been recently introduced to retain detailed motion information for high quality of video in the state-of-the-art video compression standard of H.264/AVC. Conventional sub-pixel ME algorithms in the spatial domain are faced with a common problem of computational complexity because of embedded interpolation schemes. This paper proposes a low-complexity sub-pixel motion estimation algorithm in the transform domain utilizing shifting matrix. Simulations are performed to compare the performances of spatial-domain ME algorithms and transform-domain ME algorithms in terms of peak signal-to-noise ratio (PSNR) and the number of bits per frame. Simulation results confirm that the transform-domain approach not only improves the video quality and the compression efficiency, but also remarkably alleviates the computational complexity, compared to the spatial-domain approach.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제10권4호
• /
• pp.1944-1956
• /
• 2016

The Digital Video Broadcasting-Common Scrambling Algorithm is an ETSI-designated algorithm designed for protecting MPEG-2 signal streams, and it is universally used. Its structure is a typical hybrid symmetric cipher which contains stream part and block part within a symmetric cipher, although the entropy is 64 bits, there haven't any effective cryptanalytic results up to now. This paper studies the security level of CSA against impossible differential cryptanalysis, a 20-round impossible differential for the block cipher part is proposed and a flaw in the cipher structure is revealed. When we attack the block cipher part alone, to recover 16 bits of the initial key, the data complexity of the attack is O(2^44.5), computational complexity is O(2^22.7) and memory complexity is O(2^10.5) when we attack CSA-BC reduced to 21 rounds. According to the structure flaw, an attack on CSA with block cipher part reduced to 21 rounds is proposed, the computational complexity is O(2^21.7), data complexity is O(2^43.5) and memory complexity is O(2^10.5), we can recover 8 bits of the key accordingly. Taking both the block cipher part and stream cipher part of CSA into consideration, it is currently the best result on CSA which is accessible as far as we know.