• Title, Summary, Keyword: 복잡도

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CCrash: system Complexity based kernel Crash model (CCrash: 시스템 복잡도 기반 커널 크래쉬 모델)

  • Kim, Young-Pil;Yoo, Chuck
    • Proceedings of the Korean Information Science Society Conference
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    • pp.384-388
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    • 2010
  • 일반적인 결함 문제와는 달리 커널 크래쉬는 커널 기반의 시스템에서 가장 중대하고 심각한 문제이다. 이러한 문제는 시스템이 복잡하고 거대해 질수록 문제가 심화되는데, 얼마나 야기하는지 또는 어떠한 요소들이 관련되어 있는지에 대한 연구가 미비하다. 즉, 시스템의 복잡도와 커널 크래쉬 간의 상관관계를 직접적으로 다룬 연구가 아직 존재하지 않는다. 따라서 본 논문에서는 시스템 복잡도에 관련된 요소와 전체 시스템의 커널 크래쉬 발생 확률과의 상관관계를 모델화 하여 도식하고, 분석하였다. 이를 위해 기존의 소프트웨어 복잡도 모델 중 반영할 만한 요소를 추려내고 커널 크래쉬 모델에 반영하였다. 또한 모델 분석과 수치 예제를 통해 평가하고자 하였다. 본 논문의 결과는 새로운 커널 크래쉬 처리 방안을 설계하고자 할 때, 또는 기존 커널을 분석하여 신뢰성을 향상시키는 새로운 구조 설계에 크게 활용될 수 있을 것이다.

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Model Parameter-based Rate Control Algorithm for Constant Quality Real-Time Video Coding (실시간 부호화를 위한 모델 파라미터 기반 일정 화질 비트율 제어 기법)

  • Jeong, Jin-Woo;Cho, Kyung-Min;Choe, Yoon-Sik
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.45 no.3
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    • pp.93-102
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    • 2008
  • In this paper, we propose a rate control algorithm for constant quality real time video coding. To achieve constant quality, previous algorithm exploit mean absolute of difference(MAD) as measure of frame complexity. However, if scene is abruptly changed or if quantization parameter is not constant, encoder produces various output bits with same MAD. Therefore we know that MAD does not appropriately reflect characteristic of frame. To solve this problem, we exploit model parameter as measure of frame complexity. Because model parameter means slope between output bits and MAD, it reflects correctly complexity of frame. And because previous model, R-MAD model, is not considered quantization parameter, as quantization parameter increases or decreases, model parameter of frame also vary. So model parameter obtained using previous model cannot reflect internal characteristic of video. We solve this problem using proposed model, which is considered quantization parameter. Experiment results show that our algorithm provide better performance, in terms of quality smoothness than previous algorithm. Especially, when scene is abruptly changed, our algorithm alleviates quality drop.

Statistical Characteristics and Complexity Analysis of HEVC Encoder Software (HEVC 부호화기 소프트웨어의 통계적 특성 및 복잡도 분석)

  • Ahn, Yongjo;Hwang, Taejin;Yoo, Sungeun;Han, Woo-Jin;Sim, Donggyu
    • Journal of Broadcast Engineering
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    • v.17 no.6
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    • pp.1091-1105
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    • 2012
  • In this paper, we analyzed statistical characteristics and complexity of HEVC encoder as a leading research of acceleration, optimization and parallelization. Computational complexity of the HEVC encoder is approximately twice the compression performance compared to H.264/AVC. But, the increase of encoder complexity remains a problem to be solved in the future. Before performing the research on acceleration, optimization and parallelization to reduce high complexity of HEVC encoder, we measure the complexity each module for HEVC encoder using it's reference software HM 7.1. We also measured the predicted complexity of fast HEVC encoder software, used in real applications, using HM 7.1 applying fast encoding method. The complexity is measured in terms of the operating cycle of the encoder software under the common test sequences and conditions in the Windows PC environment. In addition, we analyze statistical characteristics of HEVC encoder software according to encoding structures and limitation using coded bitstreams.

A Fast MB Mode Selection Algorithm in the H.264 Standard (H.264에서의 고속 매크로블록 모드 선택 알고리듬)

  • Kim Donghyung;Jeong Jechang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.1C
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    • pp.61-72
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    • 2005
  • For the improvement of coding efficiency, the H.264 standard uses new coding tools such as VBS, 1/4-pel accurate ME, multiple references, intra prediction, loop filter, etc. Using these coding tools, H.264 has achieved significant improvements from rate-distortion point of view compared to existing standards. However, the encoder complexity is greatly increased due to these coding tools. We focus on the complexity reduction method of MB mode selection. Among all modes which can be selected, $8{\times}8$ and intra $4{\times}4$ mode have higher complexity than the others. So we propose the methods for reduction of the $8{\times}8$ and intra $4{\times}4$ mode complexity by using information of other modes with relatively low complexity. Simulation results show that the proposed methods save up to $54.6{\%}$ of total encoding time while keeping the average decrease about 0.012dB in PSNR.

A Quantitative Analysis of the Cyclomatic Complexity of the Web Software (웹 소프트웨어의 순환복잡도에 대한 정량적 분석)

  • Kim, JeeHyun
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.2
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    • pp.183-191
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    • 2014
  • In this study Cyclomatic Complexity of Web Software has been analyzed quantitatively by correlation between complexity and Number of Classes(NOC), and Number of Methods(NOM) which are object oriented programming measures. Based on the frequency distribution of complexity, NOC and NOM of software at the Web environment, correlation between complexity threshold and NOC threshold, and NOM threshold has been measured and more than 4,000 ASP files of 10 Web real projects have been used as the sample. The empirical result shows that NOC threshold is 21, NOM threshold is 40 and complexity threshold is 68 as high value, and 8 projects among of 10 except 2 projects with especially high frequency distribution shows that NOC threshold is 12, NOM threshold is 21 and complexity threshold is 52 with relatively low value, so correlation has been found out as exists. And also 8 projects with low threshold of complexity, NOC and NOM were internal management software, and the other 2 projects were external sales service software, Number of Classes and Number of Methods can be defined at the design stage according to business properties, and also the complexity can be estimated in order to improve the software quality.

A Prediction Cost based Complexity Reduction Method for Bi-Prediction in High Efficiency Video Coding (HEVC) (HEVC의 양-예측을 위한 예측 비용 기반의 복잡도 감소 기법)

  • Kim, Jong-Ho;Lee, Ha-Hyun;Jun, Dong-San;Cho, Suk-Hee;Choi, Jin-Soo
    • Journal of Broadcast Engineering
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    • v.17 no.5
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    • pp.781-788
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    • 2012
  • In HEVC, the fast search method is used for reducing the complexity of the motion prediction procedure. It is consisted of the sub-sampled SAD which reduce the complexity of Sum of Absolute Differences(SAD) calculation and the simplified bi-prediction method which reduce the iterations of the uni-prediction for the bi-prediction. The computational complexity is largely decreased by the fast search method but the coding gain is also decreased. In this paper, the simplified bi-prediction is extended to compensate the performance loss and the prediction cost based complexity reduction methods are also proposed to reduce the complexity burden by the extended bi-prediction method. A prediction cost based complexity reduction method is consisted of early termination method for the extended bi-prediction and the bi-prediction skipping method. Compare with HM 6.0 references S/W, the average 0.42% of BD-bitrate is decreased by both the extended bi-prediction method and the prediction cost based complexity reduction methods with negligible increasement of the complexity.

The Complexity of the Static Structures of Object-Oriented Systems by Analyzing the Class Diagram of UML (UML 클래스 다이어그램의 분석에 의한 객체지향 시스템의 정적 구조 복잡도 연구)

  • Chung, Hong;Hong, Dong-Kwon
    • Journal of Korean Institute of Intelligent Systems
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    • v.14 no.6
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    • pp.793-799
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    • 2004
  • Many researches and validations for the complexity metrics of the object-oriented systems have been studied. Most of them are aimed for the measurement of the partial aspects of the systems, for example, the coupling between objects, the complexity of inheritance structures, the cohesion of methods, and so on. But the software practitioners want to measure the complexity of overall system, not partial. We studied the complexity of the overall structures of object-oriented systems by analyzing the class diagram of UML. The class diagram is composed of classes and their relations. There are three kinds of relations, association, generalization, and aggregation, which are making the structure of object-oriented systems to be difficult to understand. We proposed a heuristic metric to measure the complexity of object-oriented systems by putting together the three kinds of the relations. This metric will be helpful to the software developers for their designing tasks by evaluating the complexity of the structures of object-oriented system and redesigning tasks of the system.

A Slice-based Complexity Measure (슬라이스 기반 복잡도 척도)

  • Moon, Yu-Mi;Choi, Wan-Kyoo;Lee, Sung-Joo
    • The KIPS Transactions:PartD
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    • v.8D no.3
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    • pp.257-264
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    • 2001
  • We developed a SIFG (Slice-based Information Graph), which modelled the information flow on program on the basis of the information flow of data tokens on data slices. Then we defied a SCM (Slice-based complexity measure), which measured the program complexity by measuring the complexity of information flow on SIFG. SCM satisfied the necessary properties for complexity measure proposed by Briand et al. SCM could measure not only the control and data flow on program but also the physical size of program unlike the existing measures.

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Low-Complexity Detection Techniques for High-Density DVD Systems (고밀도 DVD시스템을 위한 저 복잡도 검출 기법)

  • Cho, Han-Gyu;Woo, Choong-Chae;Joo, Man-Sic;Kang, Chang-Eon;Hong, Dae-Sik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.10A
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    • pp.1000-1010
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    • 2002
  • Partial response maximum-likelihood (PRML) and fixed-delay tree search with decision feedback (FDTS/DF) yield a sub-optimum performance in storage systems. However, they suffer from the inevitable complexity problems. this paper focuses on detection schemes to overcome the drawbacks of the sequence detections by exploiting minimum run-length d=2. It is expected that the proposed systems yield substantial reductions of both processing speed and receiver complexity. When combined with a decision feedback equalization (DFE), they prove to keep pace with the FDTS/DF with ${\tau}$=2 and even outperform the PR(1111)ML at normalized density S>5.6.

Fast Disparity Motion Vector Searching Method for the MV-HEVC (MV-HEVC에서 빠른 변위 움직임 벡터 탐색 방법)

  • Lee, Jae-Yung;Han, Jong-Ki
    • Journal of Broadcast Engineering
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    • v.22 no.2
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    • pp.240-252
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    • 2017
  • Multi-view video codec based on the High Efficiency Video Coding (MV-HEVC) has high encoding complexity because it exploits an additional reference picture for disparity compensation prediction (DCP) when the picture of dependent view is encoded. In this paper, we propose an efficient method to reduce the complexity of disparity motion vector search for the MV-HEVC. The proposed method includes the initial search point decision method using affine transform and the adaptive search range decision method. The simulation results show that the proposed method reduces the complexity of disparity motion vector search up to 90.78% with negligible coding efficiency degradation. Also the results show that the proposed method outperforms other conventional techniques reducing complexity.