• Title/Summary/Keyword: Time Complexity

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Complexity Analysis of HM and JEM Encoder Software

  • Li, Xiang;Wu, Xiangjian;Marzuki, Ismail;Ahn, Yong-Jo;Sim, Donggyu
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2016.06a
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    • pp.264-266
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    • 2016
  • During the $2^{nd}$ JVET (Joint Group on Future Video Coding Technology Exploration) meeting, up to 22 coding tools focusing on Future Video Coding (FVC) were proposed. Despite that the application of proposed coding tools has a considerable performance enhancement, however, the encoding time of Joint Exploration Model (JEM) software is over 20 times for All Intra coding mode, 6 times for Random Access coding mode, of HEVC reference model (HM), and decoding time is 1.6 times for All Intra coding mode, 7.9 times for Random Access coding mode, of HM. This paper focuses on analyzing the complexity of the JEM software compared with HM.

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Low-Complexity Maximum-Likelihood Decoder for V-BLAST Architecture

  • Le, Minh-Tuan;Pham, Van-Su;Mai, Linh;Yoon, Gi-Wan
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.1
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    • pp.126-130
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    • 2005
  • In this paper, a low-complexity maximum-likelihood (ML) decoder based on QR decomposition, called real-valued LCMLDec decoder or RVLCMLDec for short, is proposed for the Vertical Bell Labs Layered Space-Time (V-BLAST) architecture, a promising candidate for providing high data rates in future fixed wireless communication systems [1]. Computer simulations, in comparison with other detection techniques, show that the proposed decoder is capable of providingthe V-BLAST schemes with ML performance at low detection complexity.

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STBC-OFDM Decoding Method for Fast-Fading Channels

  • Lee, Kyu-In;Kim, Jae-Kwon;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.2C
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    • pp.160-165
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    • 2007
  • In this paper, we propose a novel signal detection method that achieves the maximum likelihood (ML) performance but requires much less computational complexity than the ML detection. When the well-known linear decoding method is used for space-time block coded (STBC) OFDM systems in fast-fading channels, co-channel interference (CCI) as well as inter-carrier interference (ICI) occurs. A maximum likelihood (ML) method can be employed to deal with the CCI; however, its computational complexity is very high. In this paper, we propose a signal detection method for orthogonal space-time coded OFDM systems that achieves the similar error performance as the ML method, but requires much less computational complexity.

Key Recovery Attacks on HMAC with Reduced-Round AES

  • Ryu, Ga-Yeon;Hong, Deukjo
    • Journal of the Korea Society of Computer and Information
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    • v.23 no.1
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    • pp.57-66
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    • 2018
  • It is known that a single-key and a related-key attacks on AES-128 are possible for at most 7 and 8 rounds, respectively. The security of CMAC, a typical block-cipher-based MAC algorithm, has very high possibility of inheriting the security of the underlying block cipher. Since the attacks on the underlying block cipher can be applied directly to the first block of CMAC, the current security margin is not sufficient compared to what the designers of AES claimed. In this paper, we consider HMAC-DM-AES-128 as an alternative to CMAC-AES-128 and analyze its security for reduced rounds of AES-128. For 2-round AES-128, HMAC-DM-AES-128 requires the precomputation phase time complexity of $2^{97}$ AES, the online phase time complexity of $2^{98.68}$ AES and the data complexity of $2^{98}$ blocks. Our work is meaningful in the point that it is the first security analysis of MAC based on hash modes of AES.

Low Complexity Systolic Montgomery Multiplication over Finite Fields GF(2m) (유한체상의 낮은 복잡도를 갖는 시스톨릭 몽고메리 곱셈)

  • Lee, Keonjik
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.18 no.1
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    • pp.1-9
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    • 2022
  • Galois field arithmetic is important in error correcting codes and public-key cryptography schemes. Hardware realization of these schemes requires an efficient implementation of Galois field arithmetic operations. Multiplication is the main finite field operation and designing efficient multiplier can clearly affect the performance of compute-intensive applications. Diverse algorithms and hardware architectures are presented in the literature for hardware realization of Galois field multiplication to acquire a reduction in time and area. This paper presents a low complexity semi-systolic multiplier to facilitate parallel processing by partitioning Montgomery modular multiplication (MMM) into two independent and identical units and two-level systolic computation scheme. Analytical results indicate that the proposed multiplier achieves lower area-time (AT) complexity compared to related multipliers. Moreover, the proposed method has regularity, concurrency, and modularity, and thus is well suited for VLSI implementation. It can be applied as a core circuit for multiplication and division/exponentiation.

A Study on the Method of CAN Identifier assignment for Real-Time Network (실시간 네트워크를 위한 CAN 식별자 지정 방법에 관한 고찰)

  • 정의헌;이홍희
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.34-34
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    • 2000
  • One of the basic goals, when considering networks for communication in industrial control applications, is the reduction of complexity of related wiring harnesses. In addition, the networking offers the advantages for industrial control applications, such as ease of cabling, ease of changes in the cabling, ease of adding controller modules, etc. CAN (Controller Area Network) is generally applied in car networking in order to reduce the complexity of the related wiring harnesses. These traditional CAN application techniques are modified to achieve the real time communication for the industrial control applications. In this paper, we propose the method of CAN Identifier assignment for Real-Time network system. This method is can be used to scheduling messages on CAN for Real-Time network system. And also, the real-time network system is developed and the proposed moth(Ids are verified experimentally.

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The complexity of opt-in procedures in mobile shopping: Moderating effects of visual attention using the eyetracker (모바일 쇼핑에서 옵트인의 절차적 복잡성 연구: 아이트래커(eyetracker) 기반 시각적 주의의 조절효과)

  • Kim, Sang-Hu;Kim, Yerang;Yang, Byunghwa
    • Journal of Digital Convergence
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    • v.15 no.8
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    • pp.127-135
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    • 2017
  • Consumers tend to feel concern about disclosure of personal information and, at the same time, to avoid inconvenience of procedural complexity caused by the privacy protections. The purpose of current paper is to investigate relationships between opt-in procedural complexity and shopping behavior using smart phones, moderating by the amount of visual attentions using eyetrackers. Therefore, we created a virtual mobile Web-site in which the complexity of opt-in procedures in our experiment is manipulated and measured. Also, we measured the dwell-time of area of interest using SMI-RED 250 instrument for tracking the real eye movement. Results indicated that the levels of procedural complexity are related to repurchase, indicating a moderating effect of the amount of visual attentions. Finally, we discussed several theoretical and practical implications of management for mobile commerce.

Investigation into Longitudinal Writing Development Using Linear Mixed Effects Model (선형 혼합 모형을 통해 살펴본 쓰기 능력의 장기적인 발전 양상 탐색)

  • Lee, Young-Ju
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.2
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    • pp.315-319
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    • 2022
  • This study investigates longitudinal writing development in terms of syntactic complexity using linear mixed effects (LME) model. This study employs essays written by four case study participants. Participants voluntarily wrote essays outside of the classroom and submitted the first and second drafts, after reflecting on the automated writing evaluation feedback (i.e., Criterion) every month over one year. A total of 48 first drafts were analyzed and syntactic complexity features were selected from Syntactic Complexity Analyzer. Results of LME showed that there was a significant positive linear relationship between time and mean length of T-unit and also between time and the ratio of dependent clauses to independent clauses, indicating that case study participants wrote longer T-units and also a higher proportion of dependent clauses over one year.

A Practical Method for Predicting Initial Maintenance Time To Repair (MTTR) Using Maintenance Complexity in Equipment Design (장비 설계 시 정비복잡도를 활용한 현실적인 초기 정비시간 및 정비도(MTTR) 예측방법)

  • Shin, Sang-Hee;Lee, Hak-Jae;Hwang, Seong-Guk;Kim, Moo-Young;Kwon, Ki-Sang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.9
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    • pp.247-254
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    • 2019
  • Recently, in designing military equipment, considerable attention has been paid to maintaining operations, including reliability, maintenance, and maintenance time of equipment, from the early stages of development. Therefore, both users and developers stress the importance of design considering the maintenance time. This study evaluated the specific methodologies for predicting the realistic maintenance time, such as the access complexity of equipment, other than the standard maintenance time provided by the conventional method mil-hdbk-470a at the beginning of the design, and applied the time conversion factor using a measure of the maintenance complexity. In addition, the actual maintenance time reflecting the actual maintenance time of the developed equipment and the time-conversion factor applied was compared/verified to confirm the reliability of the data. In a study to set a target for repair and the repair of equipment design in the future, it is expected that the maintenance time of equipment that fails to measure the maintenance time for the initial actual equipment will be reflected as a more realistic time. Moreover, activities, such as research and design reflection activities, will be performed to reduce the maintenance time, operational maintenance cost, etc.

Algorithm and Implementation for Real-Time Intelligent Browsing of HD Bitstream in DTV PVR (DTV PVR에서 HD급 데이터의 실시간 지능형 검색을 위한 알고리즘 및 구현)

  • 정수운;장경훈;이동호
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.40 no.6
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    • pp.118-126
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    • 2003
  • This paper presents a low-complexity algorithm lot browsing a HD bit stream in DTV PVR according to its characteristics and also presents its implementation results. We propose an efficient algorithm which detects shots using some information after decoding MPEG-2 data, clusters them into scene and episode, and intelligently browses them according to some criteria after calculating their complexity. Some simulation results are presented to show the performance feasibility of the proposed algorithm. To implement it in real time, we propose an efficient hybrid architecture which partitions the algorithm into two parts of hardware and software. The hardware covers decoding process and extraction of some basic information which take most complexity in implementing the algorithm. The software covers the heuristic part of tile algorithm which has low complexity and needs to be expandable.