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Analysis of 3D NAND technologies and comparison between charge-trap-based and floating-gate-based flash devices
JOURNAL OF CHINA UNIVERSITIES OF POSTS AND TELECOM    2017, 24 (3): 75-82.   DOI: 10.1016/S1005-8885(17)60214-0
Abstract1000)      PDF(pc) (1498KB)(2354)       Save
NAND flash chips have been innovated from two-dimension (2D) design which is based on planar NAND cells to three-dimension (3D) design which is based on vertical NAND cells. Two types of NAND flash technologies–charge-trap (CT) and floating-gate (FG) are presented in this paper to introduce NAND flash designs in detail. The physical characteristics of CT-based and FG-based 3D NAND flashes are analyzed. Moreover, the advantages and disadvantages of these two technologies in architecture, manufacture, interference and reliability are studied and compared.
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Novel high-PSRR high-order curvature-compensated bandgap voltage reference
周前能 闫凯 林金朝 庞宇 李国权 罗伟
JOURNAL OF CHINA UNIVERSITIES OF POSTS AND TELECOM    2016, 23 (2): 66-72.  
Abstract1991)      PDF(pc) (452KB)(1423)       Save

This paper proposes a novel high-power supply rejection ratio (high-PSRR) high-order curvature-compensated CMOS bandgap voltage reference (BGR) in SMIC 0.18 μm CMOS process. Three kinds of current are added to a conventional BGR in order to improve the temperature drift within wider temperature range, which include a piecewise-curvature- corrected current in high temperature range, a piecewise-curvature-corrected current in low temperature range and a proportional-to-absolute-temperature current. The high-PSRR characteristic of the proposed BGR is achieved by adopting the technique of pre-regulator. Simulation results shows that the temperature coefficient of the proposed BGR with pre-regulator is /°C from 55 °C to 125 °C with a 1.8 V power supply voltage. The proposed BGR with pre-regulator achieves PSRR of 123.51 dB, 123.52 dB, 88.5 dB and 50.23 dB at 1 Hz, 100 Hz, 100 kHz and 1 MHz respectively.

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Cited: Baidu(1)
Web log classification framework with data augmentation based on GANs
He Mingshu, Jin Lei, Wang Xiaojuan, Li Yuan
The Journal of China Universities of Posts and Telecommunications    2020, 27 (5): 34-46.   DOI: 10.19682/j.cnki.1005-8885.2020.0020
Abstract509)      PDF(pc) (1352KB)(398)       Save
Attacks on web servers are part of the most serious threats in network security fields. Analyzing logs of web attacks is an effective approach for malicious behavior identification. Traditionally, machine learning models based on labeled data are popular identification methods. Some deep learning models are also recently introduced for analyzing logs based on web logs classification. However, it is limited to the amount of labeled data in model training. Web logs with labels which mark specific categories of data are difficult to obtain. Consequently, it is necessary to follow the problem about data generation with a focus on learning similar feature representations from the original data and improve the accuracy of classification model. In this paper, a novel framework is proposed, which differs in two important aspects: one is that long short-term memory (LSTM) is incorporated into generative adversarial networks (GANs) to generate the logs of web attack. The other is that a data augment model is proposed by adding logs of web attack generated by GANs to the original dataset and improved the performance of the classification model. The results experimentally demonstrate the effectiveness of the proposed method. It improved the classification accuracy from 89.04% to 95.04%.
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Dynamic computation offloading in time-varying environment for  ultra-dense networks: a stochastic game approach
Xie Renchao, Liu Xu, Duan Xuefei, Tang Qinqin, Yu Fei Richard, Huang Tao
The Journal of China Universities of Posts and Telecommunications    2021, 28 (2): 24-37.   DOI: 10.19682/j.cnki.1005-8885.2021.1003
Abstract352)      PDF(pc) (3234KB)(612)       Save
To meet the demands of large-scale user access with computation-intensive and delay-sensitive applications,
combining ultra-dense networks (UDNs) and mobile edge computing (MEC)are considered as important solutions.
In the MEC enabled UDNs, one of the most important issues is computation offloading. Although a number of work
have been done toward this issue, the problem of dynamic computation offloading in time-varying environment,
especially the dynamic computation offloading problem for multi-user, has not been fully considered. Therefore, in
order to fill this gap, the dynamic computation offloading problem in time-varying environment for multi-user is
considered in this paper. By considering the dynamic changes of channel state and users queue state, the dynamic
computation offloading problem for multi-user is formulated as a stochastic game, which aims to optimize the delay
and packet loss rate of users. To find the optimal solution of the formulated optimization problem, Nash 
Q-l earning
(NQLN) algorithm is proposed which can be quickly converged to a Nash equilibrium solution. Finally, extensive
simulation results are presented to demonstrate the superiority of NQLN algorithm. It is shown that NQLN algorithm
has better optimization performance than the benchmark schemes.
 
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Dynamic event-triggered leader-follower consensus of nonlinear multi-agent systems under directed weighted topology
Wu Yue, Chen Xiangyong, Qiu Jianlong, Hu Shunwei, Zhao Feng
The Journal of China Universities of Posts and Telecommunications    2023, 30 (6): 3-10.   DOI: 10.19682/j.cnki.1005-8885.2023.1019
Abstract831)      PDF(pc) (1536KB)(269)       Save
This paper studies the dynamic event-triggered leader-follower consensus of nonlinear multi-agent systems (MASs) under directed weighted graph containing a directed spanning tree, and also considers the effects of disturbances and leader of non-zero control inputs in the system. Firstly, a novel distributed control protocol is designed for uncertain disturbances and leader of non-zero control inputs in MASs. Secondly, a novel dynamic event-triggered control ( DETC) strategy is proposed, which eliminates the need for continuous communication between agents and reduces communication resources between agents. By introducing dynamic thresholds, the complexity of excluding Zeno behavior within the system is reduced. Finally, the effectiveness of the proposed theory is validated through numerical simulation.
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Joint global constraint and Fisher discrimination based multi-layer dictionary learning for image classification
Hong PENG yaozong liu
The Journal of China Universities of Posts and Telecommunications    2023, 30 (5): 1-10.   DOI: 10.19682/j.cnki.1005-8885.2023.0010
Abstract581)      PDF(pc) (890KB)(230)       Save

    A multi-layer dictionary learning algorithm that joints global constraints and Fisher discrimination (JGCFD-MDL) for image classification tasks was proposed. The algorithm reveals the manifold structure of the data by learning the global constraint dictionary and introduces the Fisher discriminative constraint dictionary to minimize the intra-class dispersion of samples and increase the inter-class dispersion. To further quantify the abstract features that characterize the data, a multi-layer dictionary learning framework is constructed to obtain high-level complex semantic structures and improve image classification performance. Finally, the algorithm is verified on the multi-label dataset of court costumes in the Ming Dynasty and Qing Dynasty, and better performance is obtained. Experiments show that compared with the local similarity algorithm, the average precision is improved by 3.34% . Compared with the single-layer dictionary learning algorithm, the one-error is improved by 1.00% , and the average precision is improved by 0.54% . Experiments also show that it has better performance on general datasets.

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Meta-heuristic optimization inspired by proton-electron swarm
The Journal of China Universities of Posts and Telecommunications    2020, 27 (3): 42-52.   DOI: 10.19682/j.cnki.1005-8885.2020.0015
Abstract393)      PDF(pc) (4683KB)(461)       Save
While solving unimodal function problems, conventional meta-heuristic algorithms often suffer from low accuracy and slow convergence. Therefore, in this paper, a novel meta-heuristic optimization algorithm, named proton-electron swarm (PES), is proposed based on physical rules. This algorithm simulates the physical phenomena of like-charges repelling each other while opposite charges attracting in protons and electrons, and establishes a mathematical model to realize the optimization process. By balancing the global exploration and local exploitation ability, this algorithm achieves high accuracy and avoids falling into local optimum when solving target problem. In order to evaluate the effectiveness of this algorithm, 23 classical benchmark functions were selected for comparative experiments. Experimental results show that, compared with the contrast algorithms, the proposed algorithm cannot only obtain higher accuracy and convergence speed in solving unimodal function problems, but also maintain strong optimization ability in solving multimodal function problems.
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Polarization-based optimal detection scheme for digital self-interference cancellation in full-duplex system
The Journal of China Universities of Posts and Telecommunications    2020, 27 (3): 73-82.   DOI: 10.19682/j.cnki.1005-8885.2020.0018
Abstract467)      PDF(pc) (1433KB)(406)       Save
In order to detect and cancel the self-interference (SI) signal from desired binary phase-shift keying (BPSK) signal, the polarization-based optimal detection (POD) scheme for cancellation of digital SI in a full-duplex (FD) system is proposed. The POD scheme exploits the polarization domain to isolate the desired signal from the SI signal and then cancel the SI to obtain the interference-free desired signal at the receiver. In FD communication, after antenna and analog cancellation, the receiver still contains residual SI due to non-linearities of hardware imperfections. In POD scheme, a likelihood ratio expression is obtained, which isolates and detects SI bits from the desired bits. After isolation of these signal points, the POD scheme cancels the residual SI. As compared to the conventional schemes, the proposed POD scheme gives significantly low bit error rate (BER), a clear constellation diagram to obtain the boundary between desired and SI signal points, and increases the receiver's SI cancellation performance in low signal to interference ratio (SIR) environment.
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Blockchain-based collaborative edge caching scheme for  trustworthy content sharing
Zhou Yutong, Li Xi, Ji Hong, Zhang Heli
The Journal of China Universities of Posts and Telecommunications    2021, 28 (2): 38-47.   DOI: 10.19682/j.cnki.1005-8885.2021.1004
Abstract377)      PDF(pc) (1645KB)(342)       Save
Moving data from cloud to the edge network can effectively reduce traffic burden on the core network, and edge collaboration can further improve the edge caching capacity and the quality of service ( QoS). However, it is difficult for various edge caching devices to cooperate due to the lack of trust and the existence of malicious nodes. In this paper,blockchain which has the distributed and immutable characteristics is utilized to build a trustworthy collaborative edge caching scheme to make full use of the storage resources of various edge devices. The collaboration process is described in this paper, and a proof of credit (PoC) protocol is proposed, in which credit and tokens are used to encourage nodes to cache and transmit more content in honest behavior. Untrusted nodes will pay for their malicious actions such as tampering or deleting cached data. Since each node chooses strategy independently to maximize its benefits in an environment of mutual influence, a non-cooperative game model is designed to study the caching behavior among edge nodes. The existence of Nash equilibrium (NE) is proved in this game, so the edge server (ES) can choose the optimal caching strategy for all collaborative devices, including itself, to obtain the maximum rewards. Simulation results show that the system can save mining overhead as well as organize a trusted collaborative edge caching effectively.  
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Design and implementation of labor arbitration system based on blockchain
Cui Hongyan CAI Ziyin Teng Shaokai
The Journal of China Universities of Posts and Telecommunications    2021, 28 (5): 36-45.   DOI: 10.19682/j.cnki.1005-8885.2021.0032
Abstract448)      PDF(pc) (2975KB)(217)       Save

Data island and information opacity are two major problems in collaborative administration. Blockchain has the potential to provide a trustable and transparent environment encouraging data sharing among administration members. However, the blockchain only stores Hash values and transactions in blocks which makes it unable to store big data and trace their changes. In this paper, a labor arbitration scheme based on blockchain was proposed to share labor arbitration data. In the system, a collaborative administration scheme that provides a big data storage model combined blockchain and interplanetary file system ( IPFS) is designed. It can store big data and share these data among different parties. Moreover, a file version control mechanism based on blockchain is designed to manage the data changes in IPFS network. It creates a tracing chain that consists of many IPFS objects to track changes of stored data. The relationship of previous and current IPFS objects recorded by blockchain can describe the changes of administration data and trace the data operations. The proposed platform is used in Rizhao City in China, and the experiment result shows collaborative administration scheme achieves traceability with high throughput and is more efficient than traditional hypertext transfer protocol ( HTTP) way to share data.

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Research on cross-chain and interoperability for blockchain system

李鸣 邱鸿霖 徐泉清 宋文鹏 Liu Baixiang
The Journal of China Universities of Posts and Telecommunications    2021, 28 (5): 1-17.   DOI: 10.19682/j.cnki.1005-8885.2021.0029
Abstract793)      PDF(pc) (3984KB)(387)       Save

At present, there is an urgent need for blockchain interoperability technology to realize interconnection between various blockchains, data communication and value transfer between blockchains, so as to break the ‘ value silo’ phenomenon of each blockchain. Firstly, it lists what people understand about the concept of interoperability. Secondly, it gives the key technical issues of cross-chain, including cross-chain mechanism, interoperability, eventual consistency, and universality. Then, the implementation of each cross-chain key technology is analyzed, including Hash-locking, two-way peg, notary schemes, relay chain scheme, cross-chain protocol, and global identity system. Immediately after that, five typical cross-chain systems are introduced and comparative analysis is made. In addition, two examples of cross-chain programmability and their analysis are given. Finally, the current state of cross-chain technology is summarized from two aspects: key technology implementation and cross-chain application enforcement. The cross-chain technology as a whole has formed a centralized fixed mechanism, as well as a trend of modular design, and some of the solutions to mature applications were established in the relevant standards organizations, and the cross-chain technology architecture tends to be unified, which is expected to accelerate the evolution of the open cross-chain network that supports the real needs of the interconnection of all chains.



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QoE-based video segments caching strategy in urban public  transportation system
Wang Hang, Li Xi, Ji Hong, Zhang Heli
The Journal of China Universities of Posts and Telecommunications    2021, 28 (4): 29-38.   DOI: 10.19682/j.cnki.1005-8885.2021.2003
Abstract520)      PDF(pc) (1902KB)(195)       Save
With the rapid development of vehicle-based applications, entertainment videos have gained popularity for  passengers on public vehicles. Therefore, how to provide high quality video service for passengers in typical public  transportation scenarios is an essential problem. This paper proposes a quality of experience (QoE)-based video  segments caching (QoE-VSC) strategy to guarantee the smooth watching experience of passengers. Consequently,  this paper considers a jointly caching scenario where the bus provides the beginning segments of a video, and the  road side unit (RSU) offers the remaining for passengers. To evaluate the effectiveness, QoE hit ratio is defined to  represent the probability that the bus and RSUs jointly provide passengers with desirable video segments  successfully. Furthermore, since passenger volume change will lead to different video preferences, a deep  reinforcement learning (DRL) network is trained to generate the segment replacing policy on the video segments  cached by the bus server. And the training target of DRL is to maximize the QoE hit ratio, thus enabling more  passengers to get the required video. The simulation results prove that the proposed method has a better  performance than baseline methods in terms of QoE hit ratio and cache costs.
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Distributed consensus of Lurie multi-agent systems under directed topology: a contraction approach
Zhang Xiaojiao, Wu Xiang
The Journal of China Universities of Posts and Telecommunications    2023, 30 (6): 11-21.   DOI: 10.19682/j.cnki.1005-8885.2023.1018
Abstract719)      PDF(pc) (3622KB)(147)       Save
This paper is devoted to investigate the consensus problems for the multi-agent systems with Lurie nonlinear dynamics in directed topology. Under some assumptions, some sufficient conditions for the systems reaching leaderless consensus and tracking consensus are established by using contraction analysis theory. Compared with the existing results, there is no need to formulate the multi-agent networks in compact form. These conditions are only related to the individual agent in lower-dimensional case and the communication topology of the network. Additionally, a generalized nonlinear function is introduced. Finally, three numerical examples are demonstrated to illustrate the effectiveness of the theoretical results.
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Review of reader antennas for UHF RFID systems
Niu Yaohui, Li Xiuping, Zhao Wenyu
The Journal of China Universities of Posts and Telecommunications    2023, 30 (5): 72-92.   DOI: 10.19682/j.cnki.1005-8885.2023.0008
Abstract145)      PDF(pc) (5205KB)(135)       Save
   Radio-frequency identification (RFID) antennas are critical components in wireless communication networks for the Internet of things (IoT). The RFID systems make it possible to realize the dynamic interconnection of various things. To better summarize the operating principles of the RFID antennas and associate antennas with specific complex applications, a review of RFID systems and antennas is necessary. In this paper, a review of reader antennas for ultra-high frequency ( UHF) RFID systems is presented, and the categories of RFID systems are summarized for the first time. The antennas are classified according to the reading region and operating principle. The reading region determines the most crucial performance that should be concentrated on when designing an antenna, while the operating principle affects the current distribution on the surface of the antenna, and further the electromagnetic radiation. By the summary of the RFID systems and antennas, the understanding of future researchers on the operating principles of the RFID antennas could be facilitated, which can be helpful in the advanced design and implementation of RFID antennas. In addition, taking engineering requirements into account, the future prospective of RFID applications is discussed, as well as the challenges to be addressed.
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Autonomous parking control for intelligent vehicles based on a novel algorithm
Hongbo Gao Guotao Xie Xin-Yu ZHANG Bo Cheng
JOURNAL OF CHINA UNIVERSITIES OF POSTS AND TELECOM    2017, 24 (4): 51-56.   DOI: 10.1016/S1005-8885(17)60223-1
Abstract1597)      PDF(pc) (932KB)(1089)       Save
Along with the increasing number of vehicles, parking space becomes narrow gradually, safety parking puts forward higher requirements on the driver’s driving technology. How to safely, quickly and accurately park the vehiclo to parking space right? This paper presents an automatic parking scheme based on trajectory planning, which analyzing the mechanical model of the vehicle, establishing vehicle steering model and parking model, coming to the conclusion that it is the turning radius is independent of the vehicle speed at low speed. The Matlab simulation environment verifies the correctness and effectiveness of the proposed algorithm for parking. A class of the automatic parking problem of intelligent vehicles is solved.
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Cited: Baidu(2)
Mining microblog user interests based on TextRank with TF-IDF factor
Tu Shouzhong, Huang Minlie
JOURNAL OF CHINA UNIVERSITIES OF POSTS AND TELECOM    2016, 23 (5): 40-46.   DOI: 10.1016/S1005-8885(16)60056-0
Abstract3642)      PDF(pc) (1273KB)(1157)       Save
It is of great value and significance to model the interests of microblog user in terms of business and sociology. This paper presents a framework for mining and analyzing personal interests from microblog text with a new algorithm which integrates term frequency-inverse document frequency (TF-IDF) with TextRank. Firstly, we build a three-tier category system of user interest based on Wikipedia. In order to obtain the keywords of interest, we preprocess the posts, comments and reposts in different categories to select the keywords which appear both in the category system and microblogs. We then assign weight to each category and calculate the weight of keyword to get TF-IDF factors. Finally we score the ranking of each keyword by the TextRank algorithm with TF-IDF factors. Experiments on real Sina microblog data demonstrate that the precision of our approach significantly outperforms other existing methods.
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Cited: Baidu(20)
Research on swarm intelligence optimization algorithm
Fei Wei Liu /Cong Hu /Sheng
The Journal of China Universities of Posts and Telecommunications    2020, 27 (3): 1-20.   DOI: 10.19682/j.cnki.1005-8885.2020.0012
Abstract829)      PDF(pc) (843KB)(550)       Save
The bionics-based swarm intelligence optimization algorithm is a typical natural heuristic algorithm whose goal is to find the global optimal solution of the optimization problem. It simulates the group behavior of various animals and uses the information exchange and cooperation between individuals to achieve optimal goals through simple and effective interaction with experienced and intelligent individuals. This paper first introduces the principles of various swarm intelligent optimization algorithms. Then, the typical application of these swarm intelligence optimization algorithms in various fields is listed. After that, the advantages and defects of all swarm intelligence optimization algorithms are summarized. Next, the improvement strategies of various swarm intelligence optimization algorithms are explained. Finally, the future development of various swarm intelligence optimization algorithms is prospected.
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Remaining useful life prediction of lithium-ion batteries using a fusion method based on Wasserstein GAN
The Journal of China Universities of Posts and Telecommunications    2020, 27 (1): 1-9.   DOI: 10.19682/j.cnki.1005-8885.2020.0004
Abstract2625)      PDF(pc) (1567KB)(10473)       Save
Lithium-ion batteries are the main power supply equipment in many fields due to their advantages of no memory, high energy density, long cycle life and no pollution to the environment. Accurate prediction for the remaining useful life (RUL) of lithium-ion batteries can avoid serious economic and safety problems such as spontaneous combustion. At present, most of the RUL prediction studies ignore the lithium-ion battery capacity recovery phenomenon caused by the rest time between the charge and discharge cycles. In this paper, a fusion method based on wasserstein generative adversarial network (GAN) is proposed. This method achieves a more reliable and accurate RUL prediction of lithium-ion batteries by combining the artificial neural network (ANN) model which takes the rest time between battery charging cycles into account and the empirical degradation models which provide the correct degradation trend. The weight of each model is calculated by the discriminator in the wasserstein GAN model. Four data sets of lithium-ion battery provided by the NASA Ames Research Center are used to prove the feasibility and accuracy of the proposed method.
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Pointer-prototype fusion network for few-shot named entity recognition
Zhao Haiying, GUO Xuan
The Journal of China Universities of Posts and Telecommunications    2023, 30 (5): 32-41.   DOI: 10.19682/j.cnki.1005-8885.2023.0011
Abstract149)      PDF(pc) (1526KB)(112)       Save

   Few-shot named entity recognition (NER) aims to identify named entities in new domains using a limited amount of annotated data. Previous methods divided this task into entity span detection and entity classification, achieving good results. However these methods are limited by the imbalance between the entity and non-entity categories due to the use of sequence labeling for entity span detection. To this end, a point-proto network ( PPN) combining pointer and prototypical networks was proposed. Specifically, the pointer network generates the position of entities in sentences in the entity span detection stage. The prototypical network builds semantic prototypes of entity types and classifies entities based on their distance from these prototypes in the entity classification stage. Moreover, the low-rank adaptation ( LoRA) fine-tuning method, which involves freezing the pre-trained weights and injecting a trainable decomposition matrix, reduces the parameters that need to be trained and saved. Extensive experiments on the few-shot NER Dataset (Few-NERD) and Cross-Dataset demonstrate the superiority of PPN in this domain.

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SNR-adaptive deep joint source-channel coding scheme for imagesemantic transmission with convolutional block attention module
Yang Yujia, Liu Yiming, Zhang Wenjia, Zhang Zhi
The Journal of China Universities of Posts and Telecommunications    2024, 31 (1): 1-11.   DOI: 10.19682/j.cnki.1005-8885.2024.2001
Abstract655)      PDF(pc) (2443KB)(126)       Save
With the development of deep learning (DL), joint source-channel coding (JSCC) solutions for end-to-end transmission have gained a lot of attention. Adaptive deep JSCC schemes support dynamically adjusting the rate according to different channel conditions during transmission, enhancing robustness in dynamic wireless environment. However, most of the existing adaptive JSCC schemes only consider different channel conditions, ignoring the different feature importance in the image processing and transmission. The uniform compression of different features in the image may result in the compromise of critical image details, particularly in low signal-to-noise ratio (SNR) scenarios. To address the above issues, in this paper, a dual attention mechanism is introduced and an SNR-adaptive deep JSCC mechanism with a convolutional block attention module (CBAM) is proposed, in which matrix operations are applied to features in spatial and channel dimensions respectively. The proposedsolution concatenates the pooling feature with the SNR level and passes it sequentially through the channel attention network and spatial attention network to obtain the importance evaluation result. Experiments show that the proposed solution outperforms other baseline schemes in terms of peak SNR (PSNR) and structural similarity (SSIM), particularly in low SNR scenarios or when dealing with complex image content.
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