• Title, Summary, Keyword: 복잡도

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Complexity Balancing for Distributed Video Coding Based on Entropy Coding (엔트로피 코딩 기반의 분산 비디오 코딩을 위한 블록 기반 복잡도 분배)

  • Yoo, Sung-Eun;Min, Kyung-Yeon;Sim, Dong-Gyu
    • Journal of Broadcast Engineering
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    • v.16 no.1
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    • pp.133-143
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    • 2011
  • In this paper, a complexity-balancing algorithm is proposed for distributed video coding based on entropy coding. In order to reduce complexity of DVC-based decoders, the proposed method employs an entropy coder instead of channel coders and the complexity-balancing method is designed to improve RD performance with minimal computational complexity. The proposed method performs motion estimation in the decoder side and transmits the estimated motion vectors to the encoder. The proposed encoder can perform more accurate refinement using the transmitted motion vectors from the decoder. During the motion refinement, the optimal predicted motion vectors are decided by the received motion vector and the predicted motion vectors and complexity load of block is allocated by adjusting the search range based on the difference between the received motion vector and the predicted motion vectors. The computational complexity of the proposed encoder is decreased 11.9% compared to the H.264/AVC encoder and that of the proposed decoder are reduced 99% compared to the conventional DVC decoder.

ISIS Architecture for Developing Complex Enterprise Applications (복잡한 엔터프라이즈 응용 개발을 위한 ISIS 아키텍처)

  • Jo, Eun-Hwan;Lee, Kap-Hoon;Lee, Min-Soo;Lee, Bong
    • Journal of KIISE:Computing Practices and Letters
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    • v.16 no.4
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    • pp.392-404
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    • 2010
  • Recently, as both business processes and IT systems become ever more complex. Especially, enterprise applications tend to become unmanageably complex and increasingly costly to maintain. Therefore complexity is the insidious enemy of software development. It is critical to have a methodology that recognizes and manages this enemy effectively. In this paper, we propose ISIS (Integrated System of Independent Subsystems) - the architectural style needed to develop the complex enterprise applications. The ISIS was developed to meet the challenge of reducing the complexity of a larger enterprise application today. It gives us architecture models for reducing development complexity and composite application. The enterprise application is partitioned into a collection of independent subsystems using ISIS decomposition schemes and equivalence relations. We use middleware named ISIS engine that provides a service for subsystems interoperability by enabling the integration of distributed, cross-platform subsystems. We have implemented an ITSM system that achieves our objectives, reducing development complexity, using the ISIS architecture. Finally, ISIS architecture provides greater flexibility and productivity when an organization needs either to change its business processes, or to update the underlying systems.

A Structural Complexity Metric for Web Application based on Similarity (유사도 기반의 웹 어플리케이션 구조 복잡도)

  • Jung, Woo-Sung;Lee, Eun-Joo
    • Journal of the Korea Society of Computer and Information
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    • v.15 no.8
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    • pp.117-126
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    • 2010
  • Software complexity is used to evaluate a target system's maintainability. The existing complexity metrics on web applications are count-based, so it is hard to incorporate the understandability of developers or maintainers. To make up for this shortcomings, entropy-theory can be applied to define complexity, however, it is assumed that information quantity of each paper is identical. In this paper, structural complexity of a web application is defined based on information theory and similarity. In detail, the proposed complexity is defined using entropy as the previous approach, but the information quantity of individual pages is defined using similarity. That is, a page which are similar with many pages has smaller information quantity than a page which are dissimilar to others. Furthermore, various similarity measures can be used for various views, which results in many-sided complexity measures. Finally, several complexity properties are applied to verify the proposed metric and case studies shows the applicability of the metric.

Performance Optimization of Tandem Source-Channel Coding Systems Employing Unequal Error Protection Under Complexity Constraints (복잡도 제한 하에서 비균등 오류 보호 기법을 사용하는 탠덤 소스-채널 코딩 시스템의 성능 최적화)

  • Lim, Jongtae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.10
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    • pp.2537-2543
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    • 2014
  • Between tandem source-channel coding systems and joint source-channel coding systems, it has been known that there is a complexity threshold in complexity versus performance. In this paper, by expanding the previous analysis for equal error protection systems, we analyze and compare the performance under complexity constrains for tandem source-channel coding systems which employ unequal error protection. Under a given complexity constraint, the optimization is performed to minimize the end-to-end distortion of each representative tandem and joint source-channel coding system. The results show that the complexity threshold for unequal error protection systems becomes smaller and the performance enhancement of unequal error protection systems over equal error protection systems gets smaller as the system complexity gets larger.

Relevance of the Cyclomatic Complexity Threshold for the Web Programming (웹 프로그래밍을 위한 복잡도 한계값의 적정성)

  • Kim, Jee-Hyun
    • Journal of the Korea Society of Computer and Information
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    • v.17 no.6
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    • pp.153-161
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    • 2012
  • In this empirical study at the Web environment based on the frequency distribution of the cyclomatic complexity number of the application, the relevance of the threshold has been analyzed with the next two assumptions. The upper bound established by McCabe in the procedural programming equals 10 and the upper bound established by Lopez in the Java programming equals 5. Which numerical value can be adapted to Web application contexts? In order to answer this 10 web site projects have been collected and a sample of more than 4,000 ASP files has been measured. After analyzing the frequency distribution of the cyclomatic complexity of the Web application, experiment result is that more than 90% of Web application have a complexity less than 50 and also 50 is proposed as threshold of Web application. Web application has the complex architecture with Server, Client and HTML, and the HTML side has the high complexity 35~40. The reason of high complexity is that HTML program is usually made of menu type for home page or site map, and the relevance of that has been explained. In the near future we need to find out if there exist some hidden properties of the Web application architecture related to complexity.

Low-Complexity Detection Techniques for Run-Length Limited Codes with d=2 (RLL(2,10) 변조 부호를 고려한 저복잡도 검출 기법)

  • 조한규;이보형;손희기;강창언;홍대식
    • Proceedings of the IEEK Conference
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    • pp.141-144
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    • 2000
  • PRML (partial response maximum-likelihood) 과 FDTS/DF (fixed-delay tree search with decision feedback)는 기록 저장 시스템에서 준최적의 성능을 보임이 잘 알려져 있다. 그러나, 위와 같은 정보열 검출 기법은 피할 수 없는 복잡도 문제를 가지고 있다. 본 논문은 최소 run 길이 제한조건 d=2를 가진 광기록 채널을 위한 다양한 저복잡도 검출 기법을 다룬다. 우선, 결정 궤환 기법을 이용한 이산 정합 여파기 (discrete matched filter with decision feedback:DMF/DF)가 기존의 PRML로부터 유도된다. 유도된 시스템은 PRML보다 결정 궤환에 의한 성능 이득을 갖는다. 또한, 메트릭 계산을 사용하지 않는 저복잡도 FDTS/DF가 유도된다. 모의실험 결과에 의하면, 유도된 저복잡도 검출 기법들은 기록 밀도 S>=5.5에서 P(D)=1+D+D/sup 2/+D/sup 3/의 target을 갖는 PRML보다 우수한 성능을 보인다.

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Effect Analysis of Program Volume on Complexity (프로그램 볼륨이 복잡도에 미치는 영향 분석)

  • 김재웅;유철중;장옥배
    • Proceedings of the Korean Information Science Society Conference
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    • pp.528-530
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    • 2000
  • 최근 객체지향 소프트웨어 개발이 일반화되면서 품질 좋은 객체지향 소프트웨어의 개발을 돕기 위한 목적으로 객체지향 소프트웨어 복잡도 척도에 관한 연구들이 다양하게 행해져 왔다. 대부분의 연구가 구조적 복잡도 측정에 중점을 두어 프로그램 크기와 관련된 요인들을 측정하는 척도들이 제시되었다. 한편 소프트웨어 개발이나 복잡도 측정에 대하여 인지 심리 이론을 적용하여, 인간의 단기 기억의 한계 7$\pm$2와 제어 논리 처리에 3$\pm$1을 고려한 연구들이 많이 행해졌다. 본 논문에서는 프로그램 볼륨과 복잡도의 관계를 조사하기 위해 13개 척도의 값을 추출한 후 통계적 분석을 수행하고, 인지 심리 이론과의 관계를 파악해 보았다.

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Linearly Decreasing K-Best List Sphere Decoding Algorithm (선형 감소 K-Best LSD 알고리즘)

  • Hong, Seokchul;Lee, Jungwoo
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.373-376
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    • 2012
  • Multiple-Input Multiple-Output (MIMO) 시스템의 복잡도를 감소시키는 방식은 실생활에서 MIMO 시스템을 활용하는 데에 있어 중요한 부분이다. 널리 사용되는 Maximum Likelihood (ML) 복호기의 경우 낮은 에러오율 (BER) 을 보여주지만 복잡도가 높다. 실생활에 활용하기 위하여 ML 복호기의 복잡도를 감소시킬 필요가 있고 이에 Sphere Decoding Algorithm (SDA) 이 제안되었다. 이를 발전시킨 List Sphere Decoding(LSD) 은 여러 종류가 있다. 그 중에 넓이 우선 탐색 방식인 K-Best LSD 알고리즘은 각 레이어에서 리스트의 크기가 복잡도와 밀접한 연관이 있다. 본 논문에서는 기존의 K-Best LSD 알고리즘에 기반하여 초기 반지름 설정 및 선형적으로 리스트 크기를 감소시키는 방식으로 K-Best LSD 알고리즘의 복잡도를 기존 알고리즘에 비해 크게 낮추면서도 비트 오율 성능 열화가 적은 알고리즘을 제안하고 전산 실험을 통해 이를 검증한다.

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Fast Intra Prediction Mode Decision for HEVC (HEVC의 고속 화면내 예측 모드 결정 기법)

  • Chang, Yong-Jun;Kim, Dong-Hyun;Kim, Jae-Gon
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.174-175
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    • 2013
  • HEVC의 화면내 예측 부호화는 예측 모드를 최대 35개까지 확장함으로써 기존H.264/AVC에 비해서 향상된 부호화 효율을 갖는다. 반면 화면내 부호화의 복잡도 또한 크게 증가하여 복잡도 감소를 위한 고속 부호화 기법이 요구된다. HEVC의 차조모델인 HM에서는 화면내 부호화 고속화를 위해 RMD(Rough Mode Decision) 과정을 통하여 후보 모드를 결정하고 선택된 후보 모드에서 초종 예측 모드를 결정한다. 본 논문에서는 화면내 부호화의 복잡도 감소를 위하여 고속 화면내 예측 모드 결정 기법을 제시한다. 본 기법은 후보 모드를 결정하기 위한 RMD 과정에서의 탐색 모드 수와후보 모드로부터 최종 모드를 결정하기 위한 탐색 모드 수를 제한하는 방법을 결합하여 모드 결정을 위한 복잡도를 감소한다. 본 제안 기법은 실험결과 HM 12.0대비 1.0%의 비트 증가로 13.19%의 복잡도를 감소시킬 수 있었다.

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A Study on Complexity Analysis of Extensible Profile Verification Software for Energy Storage System (에너지저장장치용 확장성 프로파일 검증 소프트웨어 복잡도 분석에 관한 연구)

  • Kwon, Hyeokyoung;Ryu, Youngsu;Park, Jaehong;Kwon, Kiwon
    • Journal of Internet Computing and Services
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    • v.17 no.5
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    • pp.59-65
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    • 2016
  • Recently, a study has been progressed about the energy storage system for resolving energy shortage problems in the world. The energy storage system can maximize energy storage system's energy usage by monitoring and controlling about all energy infrastructures on energy network. However, compatibility problems among main components or devices of the energy storage system are obstacles to development of energy storage system products. An extensible profile and extensible profile verification software being able to verify the extensible profile have been required in order to resolve compatibility problems. In this paper, the study on complexity analysis for the extensible profile verification software for the energy storage system is performed. A XML based profile and C language structure based profile are used for analysis of the profile verification software. The complexity of complex verification structure that parses the XML based profile several times and simple verification structure that parses the C language structure based profile are analyzed and compared. Time complexity, space complexity, and cyclomatic complexity are used for complexity analysis. By using these complexity analysis, the study result that compares and analyzes the complexity of XML based and C language structure based profile verification software is presented.