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Journal of Electronics(China) 2010年第3期27卷 305-315页

作者： Chen Jingwen Yang Fengfan Luo Lin tho le-ngoc College of Information Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China College of Information Science and Engineering Southeast University Nanjing 210096 China Department of Electrical and Computer Engineering McGill University Montreal H3A2A7 Quebec Canada

In this paper, a new kind of simple-encoding irregular systematic LDPC codes suitable for one-relay coded cooperation is designed, where the proposed joint iterative decoding is effectively performed in the destination which is in accordance with the corresponding joint Tanner graph characterizing two different component LDPC codes used by the source and relay in ideal and non-ideal relay cooperations. The theoretical analysis and simulations show that the coded cooperation scheme obviously outperforms the coded non-cooperation one under the same code rate and decoding complex. The significant performance improvement can be virtually credited to the additional mutual exchange of the extrinsic information resulted by the LDPC code employed by the source and its counterpart used by the relay in both ideal and non-ideal cooperations.

关键词： Cooperative communication Low-density parity-check code Relay channel Joint Tanner graph Joint iterative decoding

Selection of Design Parameters for Generalized Sphere Decoding Algorithms

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International Journal of Communications, Network and System Sciences 2010年第2期3卷 126-132页

作者： Ping WANG tho le-ngoc 不详

Various efficient generalized sphere decoding (GSD) algorithms have been proposed to approach optimal ML performance for underdetermined linear systems, by transforming the original problem into the full-column-rank one so that standard SD can be fully applied. However, their design parameters are heuristically set based on observation or the possibility of an ill-conditioned transformed matrix can affect their searching efficiency. This paper presents a better transformation to alleviate the ill-conditioned structure and provides a systematic approach to select design parameters for various GSD algorithms in order to high efficiency. Simulation results on the searching performance confirm that the proposed techniques can provide significant improvement.

关键词： Sphere Decoding (SD) Generalized Sphere Decoding (GSD) Maximum-likelihood (ML) Integer least-Square (ILS) MIMO λ-GSD Multi-User Detection (MUD) CDMA MC-CDMA

User Selection and Precoding Schemes Based on Partial Channel Information for Broadcast MIMO Systems

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International Journal of Communications, Network and System Sciences 2010年第4期3卷 339-349页

作者： Hamid Reza Bahrami tho le-ngoc 不详

Due to the large number of users and the time-varying characteristics of wireless channels, it is very tough to inform the transmitter of full channel information in real multi-user MIMO broadcast systems. On the other hand, the capacity of multi-user systems greatly depends on the knowledge of the channel at the transmitter while this is not always the case in single-user MIMO systems. In this paper, we investigate combined user selection and zero-forcing precoding schemes that use partial channel information, i.e., very low amount of channel information at the base station. We show that while greatly reducing the complexity and channel knowledge feedback load, the proposed schemes preserve the optimality of zero-forcing scheme in term of achievable ergodic sum capacity in limit of large number of active users.

关键词： Broadcast Channel Multi-User System Partial Channel Information Precoding

Maximum Ratio Combining Precoding for Multi-Antenna Relay Systems

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Communications and Network 2010年第2期2卷 97-103页

作者： Hamid Reza Bahrami tho le-ngoc 不详

This paper addresses the design of practical communication strategies for multi-antenna amplify-and-forward and decode-and-forward relay systems. We show that simple linear techniques at the source and destination in conjunction with maximum ratio combining can provide an optimal transmission strategy in terms of received SNR without imposing a huge computational load over the relay node(s). Besides, the structures of precoding matrices are very similar at the source and relay nodes, which reduces the complexity as all nodes can play the role of source and relay nodes without changing their transmission structure. Numerical results show that the proposed transmission and reception techniques can improve the received SNR, and hence enhance the ergodic capacity.

关键词： Cooperation Relay System Linear Precoding Maximum Ratio Combining

Accelerating BP-Based Iterative Low-Density Parity-Check Decoding by Modified Vertical and Horizontal Processes

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Journal of Southwest Jiaotong University(English Edition) 2009年第4期17卷 275-282页

作者：陈婧文仰枫帆罗琳 tho le-ngoc College of Information Science and Technology Nanjing University of Aeronautics and Astronautics College of Information Science and Engineering Southeast University Department of Electrical and Computer Engineering McGill UniversityMontreal

Two modified BP algorithms related to vertical and horizontal processes are proposed to accelerate iterative low-density parity- check （LDPC） decoding over an additive white Gaussian noise （AWGN） channel, where the newly updated extrinsic information is immediately used in the current decoding round. Theoretical analysis and simulation results demonstrate that both the modified approaches provide significant performance improvements over the traditional BP algorithm with almost no additional decoding complexity. The proposed algorithm with modified horizontal process offers even better performance than another algorithm with the modified horizontal process. The two modified BP algorithms are very promising in practical communications since both can achieve an excellent trade-off between the performance and decoding complexity.

关键词： LDPC codes Iterative decoding BP algorithm Extrinsic information Horizontal process Vertical process

Prevalence and risk factors associated with long COVID symptoms in children and adolescents in a southern province of Vietnam

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Asian Pacific Journal of Tropical Medicine 2024年第3期17卷 119-128,I0001,I0002页

作者： Huynh ngoc Linh Nguyen The Tan le Thi Minh Thu Nguyen Tu Loan Nguyen Thi To Uyen le Thanh Thao Trang Truong Thanh Nam Doan Hoang Phu Faculty of Medicine Ca Mau Medical CollegeCa Mau 98000Vietnam Ca Mau Obstetrics and Pediatrics Hospital Ca Mau 98000Vietnam Faculty of Basic Science and Public Health Dong Thap Medical CollegeDong Thap 81000Vietnam Graduate University of Sciences and Technology Vietnam Academy of Science and TechnologyHa Noi 10000Vietnam Community Public Health Research Program School of Public HealthWalailak UniversityNakhon Si Thammarat 80160Thailand Faculty Public Health Can Tho University of Medicine and PharmacyCan Tho City 94000Vietnam Doctoral Program in Health Sciences College of Graduate StudiesWalailak UniversityNakhon Si Thammarat 80160Thailand

Objective:To investigate the prevalence and risk factors associated with long COVID symptoms among children and adolescents who have recovered from ***:This study applied a cross-sectional approach within community settings in a southern province of Vietnam.A structured questionnaire featuring socio-demographic information and common long COVID symptoms was *** correlation coefficients assessed associations among pairs of long COVID ***,multivariable logistic regression models were performed to investigate the risk factors of long COVID in recovered COVID-19 children and ***:Among 422 participants,39.3%reported long COVID symptoms,with a prevalence of 45.2%(SD=0.5)in children and 22.2%(SD=0.4)in *** symptoms reported were cough 34.6%(SD=0.5),fatigue 20.6%(SD=0.4),shortness of breath 10.9%(SD=0.3),and lack of appetite 6.6%(SD=0.3).Concerning risk factors of long COVID,a higher risk was observed among demographic groups,including girls(OR 1.25,95%CI 1.15-1.37;Plescents(OR 1.24,95%CI 1.12-1.37;Pthout any COVID-19 vaccination(OR 1.36,95%CI 1.20-1.54;Ple dose(OR 1.35,95%CI 1.10-1.64;P=0.004)compared to those who have received two ***,patients with a COVID-19 treatment duration exceeding two weeks also had a higher risk of long COVID(OR 1.32,95%CI 1.09-1.60;P=0.003)than those who recovered less than seven ***:The insights from this study provide crucial guidance for predicting the factors associated with the occurrence of long COVID in pediatric patients,contributing to strategic interventions aimed at mitigating the long COVID risks among children and adolescents in Vietnam.

关键词： Long COVID Prevalence Risk factors Children Adolescent Vietnam

Optimal Scheduling of Multiple Rail Cranes in Rail Stations with Interference Crane Areas

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Intelligent Automation & Soft Computing 2024年第1期39卷 15-31页

作者： Nguyen Vu Anh Duy Nguyen le Thai Nguyen Huu tho Faculty of Engineering and Technology Nguyen Tat Thanh UniversityHo Chi Minh City700000Vietnam

In this paper,we consider a multi-crane scheduling problem in rail stations because their operations directly influence the throughput of the rail *** particular,the job is not only assigned to cranes but also the job sequencing is implemented for each crane to minimize the makespan of cranes.A dual cycle of cranes is used to minimize the number of working cycles of *** rail crane scheduling problems in this study are based on the movement of *** consider not only the gantry moves,but also the trolley moves as well as the rehandle cases are also included.A mathematical model of multi-crane scheduling is *** traditional and parallel simulated annealing(SA)are adapted to determine the optimal scheduling *** examples are conducted to evaluate the applicability of the proposed *** of the proposed parallel SA is done by comparing it to existing previous *** of numerical computation highlighted that the parallel SA algorithm outperformed the SA and gave better solutions than other considered algorithms.

关键词： Multi-crane scheduling logistics containers makespan rail stations

A Complex Fuzzy LSTM Network for Temporal-Related Forecasting Problems

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Computers, Materials & Continua 2024年第9期80卷 4173-4196页

作者： Nguyen tho thong Nguyen Van Quyet Cu Nguyen Giap Nguyen Long Giang Luong Thi Hong Lan Institute of Information Technology Vietnam Academy of Science and TechnologyHoang Quoc VietCau GiayHanoi100000Vietnam Academic Affairs Department Thai Nguyen University of EducationThai Nguyen250000Vietnam Center of Science and Technology Research and Development Thuongmai UniversityHo Tung MauCau GiayHanoi100000Vietnam Faculty of Information Technology Hanoi University of IndustryBac Tu LiemHanoi100000Vietnam

Time-stamped data is fast and constantly growing and it contains significant information thanks to the quick development ofmanagement platforms and systems based on the Internet and cutting-edge information communication *** the time series data including time series prediction has many practical *** new techniques were developed for use with various types of time series data in the prediction *** those,this work suggests a unique strategy to enhance predicting quality on time-series datasets that the timecycle matters by fusing deep learning methods with fuzzy *** order to increase forecasting accuracy on such type of time-series data,this study proposes integrating deep learning approaches with fuzzy ***,it combines the long short-termmemory network with the complex fuzzy set theory to create an innovative complex fuzzy long short-term memory model(CFLSTM).The proposed model adds a meaningful representation of the time cycle element thanks to a complex fuzzy set to advance the deep learning long short-term memory(LSTM)technique to have greater power for processing time series *** on standard common data sets and real-world data sets published in the UCI Machine learning Repository demonstrated the proposedmodel’s utility compared to other well-known forecasting *** results of the comparisons supported the applicability of our proposed strategy for forecasting time series data.

关键词： Complex fuzzy set long short-term memory(LSTM) CFLSTM T-CFLSTM

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基于BP算法的LDPC码改进译码算法

江苏航空 2008年第S1期 135-140页

作者：陈婧文仰枫帆 tho le-ngoc 南京航空航天大学信息科学与技术学院南京210016 加拿大McGill大学电气与计算机工程系

目前,LDPC码的译码主要采用MacKay和Neal提出的BP(Belief-Propagation)迭代译码算法。但其水平步骤和垂直步骤的孤立使部分外信息在下一次迭代中才能对译码产生帮助。为了使这部分外信息得到更有效的利用,本文提出两种以外信息的传递路... 详细信息

目前,LDPC码的译码主要采用MacKay和Neal提出的BP(Belief-Propagation)迭代译码算法。但其水平步骤和垂直步骤的孤立使部分外信息在下一次迭代中才能对译码产生帮助。为了使这部分外信息得到更有效的利用,本文提出两种以外信息的传递路径为导向的改进BP算法,用于LDPC码的译码。模拟显示,在加性高斯白噪声信道下,本文提出的两种方法在译码复杂度的不变或基本不变的情况下,有效加速了迭代的收敛,得到了更好的译码性能。

关键词： LDPC码迭代译码 BP算法外信息

Effect of sintering temperature on the dielectric,ferroelectric and energy storage properties of SnO_(2)-doped Bi_(0.5)(Na_(0.8)K_(0.2))_(0.5)TiO_(3)lead-free ceramics

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Journal of Advanced Dielectrics 2020年第4期10卷 13-21页

作者： Nguyen Truong-tho le Dai Vuong Department of Physics College of Sciences Hue UniversityHue CityVietnam Faculty of Natural Sciences Thu Dau Mot University Binh Duong Province Vietnam

Sintered lead-free Bi_(0.5)(Na_(0.8)K_(0.2)T_(0.5)(Ti0:96Sn0:04TO_(3)ceramics(BNKTS)have been fabricated via a solid-state *** effect of sintering temperature on the structural,morphological,dielectric,ferroelectric and energy storage properties of BNKTS ceramics was investigated,and it was found that the electrical properties of the synthesized ceramics increased with the increase in the sintering temperature,and the highest values were achieved at 1100℃.The ceramics sintered at the optimized temperature of 1100℃exhibited the best physical,dielectric,ferroelectric and energy storage properties,namely,high density(the relative density,ρ=5:88 ***^(-3),approximate to 96.7%of the theoretical value),high densification factor(DF=0:93),high dielectric constant(ε_(r)=1215),low dielectric loss(tanδ=0:051),highest dielectric constant(ε_(max)=4335),high remanent polarization(Pr=9:5μ***^(-2),high coercive field(E_(c)=14:3 kV/cm),high energy storage density(0.12 J/cm^(3),and high energy storage efficiency(41.7%at 46.3 kV/cm).

关键词： lead-free ceramics BNKT sintering temperature dielectric constant