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Journal of Beijing University of Posts and Telecommunications

  • EI核心期刊

Current Issue

    • A Review of Network Operating System Research
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 1-10.
    • Abstract ( 413 )       
    • The network operating system (NOS) is the key to breaking through the "manageable and uncontrollable" limitations of large-scale wide area networks. The future NOS is the “brain” of network that provides intelligent, secure, flexible, and customizable network capabilities, and it promotes the Internet's evolution from consumption to production kind. To achieve the "manageable and controllable" network, the current research related to NOS is analyzed, and the concept and architecture of NOS are put forward systematically. The research progress, target architecture and development trend of NOS are studied from the "data plane-control plane-service plane". Finally, the potential application scenarios are summarized.
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    • Visual Language Learning for Few-Shot Image Classification
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 11-17.
    • Abstract ( 689 )       
    • This paper proposes a method to efficiently deal with the classification of images with few samples by making full use of large-scale visual language pre-training model. Firstly, in the text encoding part, multiple learnable text s are to be integrated. The purpose is to fully explore the influence of image categories in different positions in the sentence on the generalization performance of the model. Secondly, a learnable visual is added in the image coding part to make the image pre-training parameters better represent the image with few samples. Finally, a feature adapter is added to the image and text feature encoder, and the network is fine-tuned on the image classification dataset, so that the network can achieve better performance on the few-shot image classification datasets. Extensive experimental results on 10 public datasets show that the proposed method has a significant performance improvement compared to other existing methods. For example, the average accuracy of single-sample classification is increased by 2.9%.
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    • Multi-task emotion cause pair extraction based on context and semantic modal
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 18-23.
    • Abstract ( 241 )       
    • In this paper, contextual and semantic features are modeled in detail, and Emotion Cause Pair Extraction (ECPC) is carried out on the fusion of two modal features. For context modal, BiLSTM is used to convert word embedding into clause embedding to get emotion and cause representation, and the global context matrix is obtained by two-factor attention mechanism. For semantic modal, local semantic features are obtained by constructing Graph Convolution networks (GCN) through inter-clause semantics. Finally, the fusion features are obtained by the main and auxiliary mode matching method for multi-task prediction, including emotional sentence, cause sentence and emotion-cause pair extraction task. Extensive experiments have been done to verify that contextual and semantic fusion system (CSF-ECPE) is significantly improved by 2.2% compared with the best baseline system in the classical Chinese ECPC data.
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    • A Random Beam Search Text Attack Black Box Algorithm
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 24-29.
    • Abstract ( 221 )       
    • The existing adversarial attack in black box scenario aims to propose an algorithm for generating adversarial examples with a higher attack success rate, which is of great significance for studying the vulnerability of the deep learning model of natural language processing and improving the robustness of the deep learning model. To solve the problem that existing anti text generation algorithms are prone to fall into local optimal solution, this paper proposes a method to improve the attack success rate by using random element and bundle search. This method uses beam search to increase the diversity of adversarial examples, and adds random element in the iterative process of searching for adversarial examples, so as to achieve the goal of making full use of synonym space to search for the optimal solution, optimize the problems that are easily trapped in the local optimal solution in the attack process, and improve the attack success rate. Experiments have shown that the algorithm R-attack proposed in this paper can effectively improve the success rate of attacks against adversarial examples.
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    • Non-Homogeneous Dehazing Algorithm Based on Fusion of Dual Attention and Transformer
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 30-37.
    • Abstract ( 423 )       
    • Most of the existing dehazing algorithms lack of attention to different concentrations of hazy images,which will lead to unsatisfactory recovery of the details in dense haze areas. Furthermore, image dehazing is a pixel-level reconstruction process,detail extraction is critical to image restoration. To address this issue, this paper proposes a non-homogeneous dehazing algorithm based on fusion of dual attention convolution and Transformer. Firstly, in shallow feature extraction, in order to improve the attention to areas of the dense haze, a parallel dual attention convolution network is constructed to assign different weights to the images from the perspective of pixels and channels. Secondly, in deep feature extraction, a Transformer block is integrated into the global non-homogeneous hazy region features, which can fully capture the long-range dependence between features and avoid the problem of detail loss in ordinary convolution enlarged receptive fields. Finally, a multi-feature fusion reconstruction network is designed to adaptively fuse shallow and deep features to reconstruct clear images. To verify the effectiveness of the algorithm, experiments are conducted on I-HAZE, O-HAZE, NH-HAZE, self-built non-homogeneous hazy datasets, and SOTS. The experimental results demonstrate that the proposed algorithm outperforms other state-of-the-art comparative algorithms in terms of visual effects and objective evaluation metrics.
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    • Lightweight Detection Algorithm for Detecting Surface Defects in PCB
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 38-44.
    • Abstract ( 485 )       
    • Surface defect detection for PCB, the speed and accuracy of detection need to be improved, An image detection algorithm: FFS-YOLO is proposed, which is based on the YOLO-V4-tiny framework. The calculation process of the algorithm is: Firstly, the optimized K-means clustering method was used to cluster the defect data set to solve the problem that the initial prior frame was not suitable for PCB surface defect detection. Secondly, in order to solve the problem of small-scale target information loss during down sampling, FOCUS slicing operation is introduced. Thirdly, SCC structure was introduced into PANet to improve the model receptive field and enhance the expression ability of small target features, so as to optimize the model performance. Finally, the Focal loss is used to optimize the loss function. The dataset used for algorithm experimental verification comes from the PCB surface defect dataset published by Peking University, the results showed that: the average detection accuracy of FFS-YOLO was 99.22%, FPS was 142, and the number of model parameters was 6.10MB. Compared with the classical algorithm, the detection speed, accuracy and the number of model parameters of FFS-YOLO are greatly improved.
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    • Modeling and characteristic analysis of 11GHz indoor wireless channel with passer-by influence
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 45-50.
    • Abstract ( 174 )       
    • To study the channel propagation characteristics of high frequency broadband short distance wireless communication, the wireless propagation characteristics of different indoor scenarios in 11GHz frequency band are measured. Based on lots of measurements, a path loss model with passer-by shielding is established. By the inverse Fourier transform of the measured frequency channel, the power delay profile is obtained, and the statistical characteristic of root mean square delay is presented. In addition, the influences of passer-by shielding on channel propagation characteristics in corridor, classroom and large conference room are compared and analyzed. In the presence of pedestrian, the changes in the position of pedestrian relative to the receiver have an important impact on the path loss, that is, when the pedestrian moves between the transmitter and receiver, the path loss caused by passer-by shielding has a quadratic function relationship with the distance between the pedestrian and transmitter. When the pedestrian is standing, the path loss caused by passer-by shielding and the distance between the receiver and the pedestrian has a negative exponential function relationship, and the influence level of the pedestrian on the path loss will also change depending on the scenario. The above research results can provide theoretical and practical basis for the application of high-frequency indoor short-distance wireless communication in the future.
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    • Score-based generative model for time series anomaly detection
    • Hao ZHOU
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 51-57.
    • Abstract ( 261 )       
    • To solve the problems such as the difficulty to learn the representative stochastic variables of data and poor generalization ability for traditional time series anomaly detection methods, a score-based generative model was proposed. To detect anomalies for time series data in complex Cyber-Physical Systems, a regression model based anomaly detection method was devised to capture the intrinsic temporal pattern of the multivariate time series data. Considering the stochastic of the time series generation process, the gradient information was estimated based on the denoising score matching method. Using the estimated gradient information, an efficient anomaly scoring method was devised to improve the accuracy of the time series anomaly detection task. Experiments on Pooled Server Metrics (PSM) dataset and Secure Water Treatment (SWaT) dataset showed that the proposed method can achieve F1 score of 96% and 90.18% respectively, boosting accuracy by more than 1.02% and 1.01% compared than best baseline. Furthermore, the ablation experiments and case study proved the effectiveness of each module of the proposed method.
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    • Cooperative Relay Transmission Strategy and Optimization in Rate Splitting Multiple Access System
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 58-65.
    • Abstract ( 171 )       
    • A cooperative relay transmission strategy based on rate splitting multiple access for two-user systems is presented. A more complete evaluation method for the energy cost of the cooperative rate splitting multiple access system is designed. To maximize system efficiency, precoded matrices, common rate allocation, transmit power, and time allocation are jointly optimized. The golden section search method and successive convex approximation are used to transform the non-convex problem into a convex problem and solve it. The simulation results show that compared with the benchmark scheme, the proposed scheme can achieve higher system efficiency.
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    • Discrete wavelet analysis and self-encoder coupling for EEG signal abnormality detection
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 66-73.
    • Abstract ( 205 )       
    • Epilepsy is a common neurological disorder that is usually detected by electroencephalographic (EEG) signals. Visual inspection and interpretation of EEG is a slow, time-consuming process that is prone to errors and subjective variations. A discrete wavelet transform (DWT) and autoencoder (AE) coupled signal abnormality detection method is proposed to distinguish seizure signals from normal (seizure-free) signals. First, the wavelet transform is used to decompose the EEG signal into approximation and detail coefficients, and the number of wavelet coefficients is limited by rejecting insignificant coefficients according to the threshold criterion. Secondly, the DWT coefficients were encoded using a self-encoder. Finally, the EEG signal was analyzed to detect outliers, data reconstruction was performed by compressing the feature set, and a neural network classifier was used to detect epileptiform activity from epileptic-free signals. The results of this method were compared and validated with those of previous methods using the Bonn University database. The method achieved a good classification performance (99.93% accuracy, 100% specificity) using linear and nonlinear machine learning classifiers to detect seizure activity from EEG data. Therefore, this method can be considered as robust with good detection ability to distinguish seizure activity, seizure-free activity, and normal EEG activity with a simple linear classifier. The method is suitable for time series signal analysis with further detection and determination of abnormalities. The method of detecting abnormal EEG signals in epilepsy can provide an objective reference for diagnosing, treating, and evaluating epilepsy. Thus, it can reduce physicians' workload and improve treatment efficiency, which has important theoretical significance and practical application value.
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    • SCLF Decoding Algorithm of Polar Codes Based on the Improved First Critical Set
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 74-80.
    • Abstract ( 167 )       
    • In view of the fact that the current successive cancellation list bit-flip (SCLF) does not fully consider the influence of the previous bits decoding on the current bit decoding, this paper proposes a successive cancellation list bit-flip algorithm based on the improved first critical set (IFCS-SCLF). The algorithm takes the first critical set (FCS) as the initial critical set. Then, the theoretical bit unreliability is calculated by the channel error probability and the actual decoding bit unreliability is calculated by the path metric obtained through the cyclic redundancy check aided SCL (CA-SCL). If the bits with actual unreliability is higher than the theoretical value, the error possibility of the bits are higher and will be selected from the SC path status in the first critical set and arranged in ascending order of channel reliability to construct the improved first critical set (IFCS). Finally, the decision results on the SC state path in IFCS are exchanged when the first CA-SCL decoding fails. Simulation results show that the proposed algorithm has better bit error performance and lower complexity than the RCS-SCLF and the D-Post SCLF decoding algorithms, and it can be combined with CA-SCL decoder of small list size to achieve the similar decoding performance of large list size.
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    • Deep reinforcement learning-based power allocation in vehicular edge computing networks
    • Yunxiao Wang Hailin Xiao
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 81-89.
    • Abstract ( 201 )       
    • A deep reinforcement learning-based computation offloading and power allocation algorithm is proposed to address the time-varying channel and stochastic task arrival problems caused by the mobility of vehicle in the vehicular edge computing environment. In this paper, we first build a three-layer system model for end-edge-cloud orchestrated computing based on non-orthogonal multiple access in a two-way lane scenario. By combining the communication, computing, cache resources and the mobility of vehicle, a joint optimization problem is designed to minimize the long-term cumulative total system cost consisting of power consumption and cache latency. Furthermore, in view of the dynamics, time-varying and stochastic characteristics in vehicular edge computing networks, a decentralized intelligent algorithm based on deep deterministic policy gradient (DDPG) is proposed for obtaining the power allocation optimization. Compared with conventional baseline algorithms, the simulation results illustrate that the proposed algorithm can achieve a superior performance in reducing the system total cost.
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    • Dynamic Gesture Data Optimization and Recognition Based on Encoded Video
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 90-96.
    • Abstract ( 156 )       
    • The syntax elements extract from encoding video data streaming, such as motion vectors and residuals, can be used to characterize the motion of action recognition and obtain the better precision than optical-flow. But its inherent pixel noise and feature sparsity may also lead to some error when fine movements recognized. To address these issues, a dynamic gesture recognition framework was designed to get higher-precision and lower-complexity, by using the data optimization of syntax elements in coding video. Specifically, a key P-frame selection strategy is introduced to cope with the feature sparsity by selecting encoding frames which cover higher information content. Moreover, a joint residual feature representation method is proposed to remove the noisy motion vectors outside the hand by using finer gesture contour maps obtained from residuals. It is demonstrated that the presented model achieves the similar computation effects as optical flow. Experiments on the baseline dataset, VIVA dataset, SKIG dataset, NvGesture and EgoGesture dataset, the results show that the scheme achieves an average recognition accuracy of 82.94%, 99.72%, 81.12% and 90.48% using only RGB data, reducing storage overhead by 89% and achieving similar results to SOTA methods at 4.7 times the operating speed.
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    • Certificateless batch verification signature scheme based on dynamic vehicle insurance assessment
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 97-102.
    • Abstract ( 123 )       
    • The dynamic vehicle insurance evaluation mode based on Vehicular ad-hoc network(VANET) analyzes user behavior by collecting real-time data, and then realizes the behavior driven of insurance fee collection. However, providing real-time data can easily lead to the disclosure of private information, which might discourage users from contributing data and thus affect the effectiveness of the evaluation. This paper designs a novel ring signature scheme to preserve user privacy by implementing broken links between data uploaders and data. When the quantity of data increases, this solution relies on the batch verification algorithm to reduce the signature verification overhead of the data collection platform and improve verification efficiency. Meanwhile, the selective conversion mechanism from anonymous signature to normal signature is designed to verify whether the user is the owner of the data in response to the user's need to declare the ownership of the data. The experimental results show that the computational overhead of the single signature process does not increase significantly in this scheme with a larger number of signing users, and the efficiency of the server-side signature verification is much higher than that of existing schemes. When both the signature group and the number of signatures increase, this scheme still maintains better performance.
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    • Dynamic event-triggered consensus control of multi-agent systems with communication link information known
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 103-109.
    • Abstract ( 219 )       
    • This paper investigates the consensus problem of multi-agent systems with communication link information known via dynamic event-triggered control. Specifically, the proposed dynamic event-triggered mechanism takes account of channel capacity in the triggering condition, which makes the frequency of information exchange between agents vary with the change of communication resources. That is, to reduce the communication volume when the communication link status is poor, and vice versa. Furthermore, to avoid the use of global topology information so as to be scalable with large systems, an adaptive coupling gain that converges to a finite steady-state value is introduced to form a fully distributed communication link information dynamic event-triggered consensus control scheme. Compared with traditional event-triggered mechanisms, we show that the proposed communication link-aware dynamic event-triggered consensus control protocol can balance the triggering frequency between communication resources and convergence speed. When communication resources are sufficient, the convergence speed is faster than that of traditional event-triggered mechanisms. When communication resources are insufficient, the triggering frequency is less than that of traditional mechanisms.
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    • Research on Flow Deterministic Transmission in Smart Substation based on TSN
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 110-117.
    • Abstract ( 207 )       
    • There are many kinds of traffic in the communication network of smart substations, and there are unexpected event messages with low delay requirements. At present, smart substation adopts hierarchical networking and point-to-point communication mode for data transmission. In order to achieve the deterministic transmission of all messages in the same network, a TSN-based networking scheme for smart substation called " entire substation sharing network " is designed to realize mixed transmission of various types of smart substation messages in the same network. For the periodic and unexpected event-driven traffic in the smart substation, the time-aware shaper function in TSN 802.1Qbv is used to schedule all traffic with time-delay requirements in the network, formulate traffic scheduling constraints, and calculate configuration parameters of network device for traffic transmission. The simulation experiment is designed, and the calculated configuration parameters are configured to the TSN node in the simulation experiment, so that the traffic is transmitted according to the solved time slot. In the simulation experiment, multiple groups of comparative experiments were carried on the presence or absence of Qbv scheduling and interference from background traffic. Experiments show that the Qbv scheduling strategy can ensure the mixed transmission of multiple traffic in smart substation, and the traffic with strict delay requirements can be transmitted in the special time slot. The scheduled traffic is not interfered by the background traffic, achieving low delay and deterministic transmission of messages in the smart substation.
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    • Research on image defogging algorithm based on dark channel prior and particle swarm optimization
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 118-122.
    • Abstract ( 171 )       
    • In the case of haze,aiming at the shortcomings of traditional fixed-value dark channel prior algorithm,such as low image quality and color distortion,an improved dark channel prior and particle swarm optimization algorithm is proposed. According to the characteristics of the particle swarm optimization algorithm,the best value of the retention factor in each average brightness range is optimized and brought into the dark channel prior algorithm. At the same time,the median filtering algorithm is used to replace the original two minimum filtering algorithm when solving the atmospheric light value. The experimental results show that the proposed algorithm has better subjective visual effect and objective evaluation criteria in image defogging compared with the traditional fixed value dark channel prior algorithm,and the operation speed of the algorithm is improved by about 14.3%.
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    • A Retrieval Model of Engineering Consulting Report Based on Joint Semantic and Association Matching
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 123-129.
    • Abstract ( 137 )       
    • Writing engineering consulting reports requires writers to collect and read a large number of government policy documents, news reports, etc. There exist some problems such as high labor cost and long writing cycle. How to use text retrieval technology to intelligently match relevant paragraphs and recommend them to writers become particularly important. Proposes a text retrieval model for engineering consulting reports, abbreviated as JSAM, which combines semantic matching and association matching to achieve accurate and efficient retrieval of titles and paragraphs, and can effectively assist the writing of engineering consulting reports. A text retrieval corpus for engineering consulting reports is constructed. The comparative learning model of simCSE is fine-tuned by the corpus set. The Vanilla BERT model is initialized by the obtained model parameters, and the semantic matching score is obtained by sending the text information of the corpus into the Vanilla BERT model. At the same time, the text information and keyword information are represented by word-level semantic primitive vectors through the SAT model, and sent to the deep text interaction model DRMM to obtain the association matching score. The obtained semantic matching score and association matching score are normalized and then weighted and fused to obtain the final matching score, and the text retrieval between the title and the paragraph is completed. Compared with the comparative model CEDR-DRMM, the JSAM combines context vector representation and text interaction matching method, which improves the evaluation index of P@20 by 4.03 percentage points and effectively enhances the effect of text retrieval.
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    • Research on AGV System Planning of Express Distribution Center Considering Load Balancing
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 130-136.
    • Abstract ( 145 )       
    • To address the load imbalance in the road network that occurs during the deployment of Automated Guided Vehicles (AGVs) in express distribution center, a multi-objective hierarchical model that considers load balancing is developed. The model is pre-processed using the A* algorithm, which considers the cost of turning. Based on this, the nodal load cost is introduced. Then, to complete the optimization of the drop point layout, a hybrid genetic algorithm is used with the optimization objectives of minimizing the path cost and maximizing the load balance. The load cost is added to the improved A* algorithm as part of the fitness function to obtain the fitness function value. Finally, simulation experiments were conducted in a raster map. The results show that the model can effectively balance the load of the road network by optimizing the layout of courier distribution center drop-off points and achieve good load balance.
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    • On the Capacity of Optical Wireless Channels Based on IM-DD
    • Journal of Beijing University of Posts and Telecommunications. 2024, 47(2): 137-142.
    • Abstract ( 203 )       
    • Most of current optical wireless communication (OWC) systems use the intensity modulation-direct detection (IM-DD) method to convey information. Existing results on the capacity analysis of OWC channels based on IM-DD cannot give good approximations to the capacity at finite SNR. In the light of this, with duality capacity expression, by choosing an auxiliary output distribution, a new capacity upper bound on the capacity is derived. Compared with existing capacity bounds, numerical results show that the upper bound gives better approximation to the capacity at moderate and high SNR, and is asymptotically tight at high SNR. Also, by using the properties of discrete input entropy, combined with maximum entropy argument, a new capacity lower bound is derived. Numerical results show that the lower bound significantly improves the performance of capacity approximation at low and moderate SNR.
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