• Title/Summary/Keyword: a rate of convergence

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Combined Horizontal-Vertical Serial BP Decoding of GLDPC Codes with Binary Cyclic Codes (이진 순환 부호를 쓰는 GLDPC 부호의 수평-수직 결합 직렬 복호)

  • Chung, Kyuhyuk
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.10
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    • pp.585-592
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    • 2014
  • It is well known that serial belief propagation (BP) decoding for low-density parity-check (LDPC) codes achieves faster convergence without any increase of decoding complexity per iteration and bit error rate (BER) performance loss than standard parallel BP (PBP) decoding. Serial BP (SBP) decoding, such as horizontal SBP (H-SBP) decoding or vertical SBP (V-SBP) decoding, updates check nodes or variable nodes faster than standard PBP decoding within a single iteration. In this paper, we propose combined horizontal-vertical SBP (CHV-SBP) decoding. By the same reasoning, CHV-SBP decoding updates check nodes or variable nodes faster than SBP decoding within a serialized step in an iteration. CHV-SBP decoding achieves faster convergence than H-SBP or V-SBP decoding. We compare these decoding schemes in details. We also show in simulations that the convergence rate, in iterations, for CHV-SBP decoding is about $\frac{1}{6}$ of that for standard PBP decoding, while the convergence rate for SBP decoding is about $\frac{1}{2}$ of that for standard PBP decoding. In simulations, we use recently proposed generalized LDPC (GLDPC) codes with binary cyclic codes (BCC).

OPTIMAL PORTFOLIO CHOICE IN A BINOMIAL-TREE AND ITS CONVERGENCE

  • Jeong, Seungwon;Ahn, Sang Jin;Koo, Hyeng Keun;Ahn, Seryoong
    • East Asian mathematical journal
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    • v.38 no.3
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    • pp.277-292
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    • 2022
  • This study investigates the convergence of the optimal consumption and investment policies in a binomial-tree model to those in the continuous-time model of Merton (1969). We provide the convergence in explicit form and show that the convergence rate is of order ∆t, which is the length of time between consecutive time points. We also show by numerical solutions with realistic parameter values that the optimal policies in the binomial-tree model do not differ significantly from those in the continuous-time model for long-term portfolio management with a horizon over 30 years if rebalancing is done every 6 months.

Design and Development of T-DMB Multichannel Audio Service System Based on Spatial Audio Coding

  • Lee, Yong-Ju;Seo, Jeong-Il;Beack, Seung-Kwon;Jang, Dae-Young;Kang, Kyeong-Ok;Kim, Jin-Woong;Hong, Jin-Woo
    • ETRI Journal
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    • v.31 no.4
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    • pp.365-375
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    • 2009
  • In this paper, a terrestrial digital multimedia broadcasting (T-DMB) multichannel audio broadcasting system based on spatial audio coding is presented. The proposed system provides realistic multichannel audio service via T-DMB with a small increase of data rate as well as backward compatibility with the conventional stereo-based T-DMB player. To reduce the data rate for additional multichannel audio signals, we compress the multichannel audio signals using the sound source location cue coding algorithm, which is an efficient parametric multichannel audio compression technique. For compatibility, we use the dependent property of an elementary stream descriptor, and this property should be ignored in a conventional T-DMB player. To verify the feasibility of the proposed system, we implement the T-DMB multichannel audio encoder and a prototype player. We perform a compatibility test using the T-DMB multichannel audio encoder and conventional T-DMB players. The test demonstrates that the proposed system is compatible with a conventional T-DMB player and that it can provide a promisingly rich audio service.

Robust Sign Recognition System at Subway Stations Using Verification Knowledge

  • Lee, Dongjin;Yoon, Hosub;Chung, Myung-Ae;Kim, Jaehong
    • ETRI Journal
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    • v.36 no.5
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    • pp.696-703
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    • 2014
  • In this paper, we present a walking guidance system for the visually impaired for use at subway stations. This system, which is based on environmental knowledge, automatically detects and recognizes both exit numbers and arrow signs from natural outdoor scenes. The visually impaired can, therefore, utilize the system to find their own way (for example, using exit numbers and the directions provided) through a subway station. The proposed walking guidance system consists mainly of three stages: (a) sign detection using the MCT-based AdaBoost technique, (b) sign recognition using support vector machines and hidden Markov models, and (c) three verification techniques to discriminate between signs and non-signs. The experimental results indicate that our sign recognition system has a high performance with a detection rate of 98%, a recognition rate of 99.5%, and a false-positive error rate of 0.152.

Stable Tracking Control to a Non-linear Process Via Neural Network Model

  • Zhai, Yujia
    • Journal of the Korea Convergence Society
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    • v.5 no.4
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    • pp.163-169
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    • 2014
  • A stable neural network control scheme for unknown non-linear systems is developed in this paper. While the control variable is optimised to minimize the performance index, convergence of the index is guaranteed asymptotically stable by a Lyapnov control law. The optimization is achieved using a gradient descent searching algorithm and is consequently slow. A fast convergence algorithm using an adaptive learning rate is employed to speed up the convergence. Application of the stable control to a single input single output (SISO) non-linear system is simulated. The satisfactory control performance is obtained.

STANCU TYPE GENERALIZATION OF MODIFIED GAMMA OPERATORS BASED ON q-INTEGERS

  • Chen, Shu-Ni;Cheng, Wen-Tao;Zeng, Xiao-Ming
    • Bulletin of the Korean Mathematical Society
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    • v.54 no.2
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    • pp.359-373
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    • 2017
  • In this paper, we propose the Stancu type generalization of a kind of modified q-Gamma operators. We estimate the moments of these operators and give the basic convergence theorem. We also obtain the Voronovskaja type theorem. Furthermore, we obtain the local approximation, rate of convergence and weighted approximation for these operators.

Structural Convergence Improvement Schemes on Adaptive Control Redesigning a Lyapunov's Function (Lyapunov 함수를 재설계한 적응제어외의 구조적 수렴향상 방법에 대한 연구)

  • Kang, Hoon
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.1
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    • pp.1-9
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    • 1989
  • The convergence analysis of adavtive control schemes has been studied over the past decades, but the importance of structure to fast conversgece of adaptive control systems is still a controversial issue. This paper deals with the relative improvement of the exponential rate of convergence in adaptive error models. The Lyapunov's direct method is applied to adaptive control systems in order to improve the convergence rate by modifying the feedback structure of the error systems. Some simulation examples are illustrated to show fast convergence and robustness of these schemes.

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SMOSLG Algorithm for Digital Image Restoration (디지털 영상복원을 위한 SMOSLG 알고리즘)

  • Song, Min-Koo;Yum, Joon-Keun
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.12
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    • pp.3694-3702
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    • 1999
  • OSL algorithm has an advantage that repeated algorithm is easily derived, even though penalty function which has a complicated transcendental function. In order to solve this problem, we suggested MPEMG algorithm. However, though this algorithm extend convergence rate of smoothing constant, it include the problem that is not faster than OSL algorithm in the convergence rate increasing penalized log-likelihood. Accordingly, in this paper, we will suggest SMOSLG digital image restoration algorithm which is fast in the convergence rate as well as extend convergence region of smoothing constant. And also we will study the usefulness of algorithm suggested through digital image simulation.

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16-QAM-Based Highly Spectral-Efficient E-band Communication System with Bit Rate up to 10 Gbps

  • Kang, Min-Soo;Kim, Bong-Su;Kim, Kwang Seon;Byun, Woo-Jin;Park, Hyung Chul
    • ETRI Journal
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    • v.34 no.5
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    • pp.649-654
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    • 2012
  • This paper presents a novel 16-quadrature-amplitude-modulation (QAM) E-band communication system. The system can deliver 10 Gbps through eight channels with a bandwidth of 5 GHz (71-76 GHz/81-86 GHz). Each channel occupies 390 MHz and delivers 1.25 Gbps using a 16-QAM. Thus, this system can achieve a bandwidth efficiency of 3.2 bit/s/Hz. To implement the system, a driver amplifier and an RF up-/down-conversion mixer are implemented using a $0.1{\mu}m$ gallium arsenide pseudomorphic high-electron-mobility transistor (GaAs pHEMT) process. A single-IF architecture is chosen for the RF receiver. In the digital modem, 24 square root raised cosine filters and four (255, 239) Reed-Solomon forward error correction codecs are used in parallel. The modem can compensate for a carrier-frequency offset of up to 50 ppm and a symbol rate offset of up to 1 ppm. Experiment results show that the system can achieve a bit error rate of $10^{-5}$ at a signal-to-noise ratio of about 21.5 dB.