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• • 2019, Vol. 42 No. 5 Published date:28 October 2019 Last issue Next issue

  • A Mechanized Proof of Equivalence Between the Axiom of Choice and Tukey’s Lemma
  • SUN Tian-yu, YU Wen-sheng
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 1-7. DOI:10.13190/j.jbupt.2019-001
  • Abstract ( 507 )     HTML     　　
  • On the basis of the computer proof assistant Coq, a formal proof of the equivalence between the axiom of choice and Tukey's lemma is presented. The formal description of axiom of choice and Tukey lemma was given based on the "axiomatic set theory" formal system, which was the first formalization of Tukey's lemma. A complete proof code of the equivalence between the axiom of choice and Tukey's lemma was completed. All the proofs were formally checked in Coq. The formal proof demonstrated that the Coq-based mechanized proof of mathematics theorem had the characteristics of readability and interactivity. The proof process was standardized, rigorous and reliable. This formal work has important applications in many fields of formal mathematics, especially in set theory, topology and algebra.
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  • Implicit Overrelaxation LU-SGS Discontinuous Galerkin Finite Element Algorithm
  • DUAN Zhi-jian, XIE Gong-nan, ZHANG Ying-chun
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 8-14. DOI:10.13190/j.jbupt.2019-023
  • Abstract ( 514 )     HTML     　　
  • In order to improve the computational efficiency of solving Euler equation and Navier-Stokes equation, the discontinuous Galerkin finite element method was investigated by combining with the implicit time discrete scheme. The lower upper-symmetric Gauss-Seidel(LU-SGS) scheme was improved through retaining the round-off error item, and an overrelaxation interior iteration LU-SGS discrete scheme was constructed to realize the calculation of unsteady compressible flow fields. The reliability and accuracy of the algorithm were verified by solving the Sod shock tube problem and the two-dimensional pipeline problem. The transonic compressible flows around RAE2822 airfoil and ONERA M6 wing were numerically calculated, and the results were compared with that of the multistep Runge-Kutta(RK) algorithm, LU-SGS algorithm and generalized minimal residual algorithms(GMRES). The results show that the presented algorithm has good stability and efficiency, and its computational efficiency is 2.35~3.1 times that of LU-SGS scheme and 5.4 times that of RK scheme.
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  • Parameter Identification of Chaotic Systems Based on High-Order Correlation Computations
  • WU Lin-chong, YAN Zi-xiang, XIAO Jing-hua
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 15-21. DOI:10.13190/j.jbupt.2019-021
  • Abstract ( 471 )     HTML     　　
  • In order to reduce the influence of system nonlinearity and noise on the effect of parameter identification, the high-order correlation computations (HOCC) with missing variables and noise is used to identify the dynamic parameters of real chaotic Chua's circuit, based on both simulation and experimental data of a single chua's circuit and a coupled chua's circuit. The results showed that the relative errors between identifications and calibration parameters of the experiments can be controlled within 20%, which means HOCC not only has good robustness to noise but also solves the problem produced by the missing data of the current of inductance. This work provided a benchmark for the measurement of instrument parameters of Chua's circuit, and could further apply on the parameter identification of other complicated networks.
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  • Robotic Sorting Method in Complex Scene Based on Deep Neural Network
  • HAN Xing, LIU Xiao-ping, WANG Gang, HAN Song
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 22-28. DOI:10.13190/j.jbupt.2019-015
  • Abstract ( 476 )     HTML     　　
  • A robotic sorting method based on deep neural network in complex scene is proposed to improve the sorting efficiency and recognition accuracy of parcels. The sorting method consists of three main parts. Firstly, the improved object detection algorithm is proposed. More detailed features are extracted by combining the multi-layer shallow layer with the final feature map to improve the speed and accuracy of recognition. Then, an optimal grab position detection network based on cascading convolution of key points is proposed to realize real-time estimation of the optimal sorting position of the parcel. Finally, by combining with the target capture optimal frame and the depth information of the scene, the robotic sorting operation can be completed by the target pose estimation algorithm based on the three-dimensional information, and the effectiveness of the method is verified by experiments.
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  • Time-Varying Channel Modeling Using Least Square Support Vector Machine
  • ZHAO Xiong-wen, SUN Ning-yao, GENG Sui-yan, ZHANG Yu, DU Fei
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 29-35. DOI:10.13190/j.jbupt.2019-008
  • Abstract ( 471 )     HTML     　　
  • Based on 2.55 GHz urban microcellular multiple-input multiple-output (MIMO) channel measurement data, the least squares support vector machine (LS-SVM) method was applied on time-varying channel model. Specifically, a genetic algorithm (GA) based LS-SVM (GA+LS-SVM) model was established for channel parameter prediction. Based on GA+LS-SVM model, the time-varying channel parameters, such as delay spread, horizontal angle spread and vertical angle spread of receiver, were investigated and predicted accurately. Moreover, the GA+LS-SVM model was compared with back propagation neural network and traditional LS-SVM algorithms to verify the effectiveness of the algorithm. In summary, with limited amount of data the GA based LS-SVM model can better adapt to non-linear time-varying channel to realize the accurate prediction of nonlinear time-varying channel parameters.
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  • Dynamic Time Allocation Strategy of Opportunity Cooperative Relay System for Optimizing Transmission Performance
  • LI Tao-shen, NING Qian-li, WANG Zhe
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 36-41,99. DOI:10.13190/j.jbupt.2019-007
  • Abstract ( 381 )     HTML     　　
  • A dynamic time allocation strategy for opportunistic cooperative relay system was proposed to optimize the transmission and extend the life cycle of energy-constrained nodes in energy harvesting wireless network. The relationship between outage probability and time distribution coefficient was derived under the constraint of satisfying the minimum transmission rate of the system. By reducing the system outage probability, the time allocation coefficient was optimized and the expression of the system throughput and energy efficiency was deduced. A suboptimal iteration time allocation algorithm was designed to solve the problem. The simulation results show that the proposed strategy is of higher system throughput and energy efficiency under the non-ideal channel condition, which will optimize the transmission performance and improve the reliability of the system.
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  • Improved MUSIC Algorithm for HF Direction Finding System with Non-Regular Antenna Array
  • LIU Yin-sheng, DUAN Hong-tao, FAN Zhen-xiong, LI Rong, LI Jing-chun
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 42-47. DOI:10.13190/j.jbupt.2019-006
  • Abstract ( 528 )     HTML     　　
  • Traditional high frequency (HF) finding system needs a large and plain area for antenna array, so it is difficult to find a suitable place for practical HF direction finding systems. To address this issue, an improved mutiple signal classification (MUSIC) algorithm is proposed for HF direction finding system with non-regular antenna array. This algorithm makes it possible to deploy HF direction finding system not only in plain area but also in the conditions of complex terrain, which makes it much easier to find a place to deploy HF direction finding system. On the basis of theoretical modeling and computer simulation, a prototype system of HF irregular array direction finding was developed and tested in the real environment. The experiment results showed that the improved MUSIC algorithm was available for direction finding in the condition of non-regular antenna array, and the corresponding HF direction finding systems can work well with complex terrain conditions.
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  • Power Matching Algorithm Considering Service Dynamics in Ultra-Dense Scenarios
  • ZHANG Hui, LIU Shu, ZHAO Hai-tao, SUN Yan-fei
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 48-53. DOI:10.13190/j.jbupt.2019-002
  • Abstract ( 465 )     HTML     　　
  • A wireless network resource matching algorithm considering service dynamics in ultra-dense scenarios is proposed. Firstly, according to heterogeneous characteristics of networks and dynamic changes of services, a two-layer dynamic game model was established. In particular, different benefit models were designed to maximize the utility function based on the demand characteristics of different game layer participants, and a pricing factor was dynamically adjusted by predicting service dynamics more accurately to reflect the network environment. Secondly, according to the characteristics of the two-tier non-cooperative game model, a layered power game was solved, so that an equilibrium was achieved through multiple non-cooperative power games among macro cell users, micro base stations and micro cell users. Finally, compared with several existing resource matching algorithms, the simulation results of our algorithm showed superior performances.
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  • Research on Dynamic Energy Management for the Base Station Supplied by Smart Grid with Time-Varying Price
  • LIU Di-di, MA Li-na, SUN Hao-tian, HU Cong
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 54-61. DOI:10.13190/j.jbupt.2018-320
  • Abstract ( 430 )     HTML     　　
  • A dynamic energy management scheme of the energy harvesting base station powered by the smart grid with time-varying price is proposed. Specially, it was assumed that the base stations(BSs) were equipped with energy harvesting device, and the free energy collected by this device from renewable sources were stored in battery for BSs to use in future. Due to the randomness of energy harvest, smart grid was taken as a supplement of energy to ensure the stable operation of BSs. Based on queuing theory and Lyapunov optimization method, a dynamic energy management algorithm was proposed for BSs under two conditions of inelastic energy demand and elastic energy demand. Based on the proposed algorithm, BSs can dynamically choose to purchase energy from smart grid at low price and store it in battery for using at high price for reducing the energy cost of BSs. The proposed dynamic energy management algorithm has low complexity and does not need prior statistical information of energy collection, energy demand and time-varying price. The theoretical analysis showed that the proposed algorithm performed arbitrarily close to the optimal objective value, meanwhile, it ensured that the time delay did not exceed the tolerable time. Finally, simulation results showed the validity of the algorithm. And the effect of battery capacity on the performance of the algorithm was analyzed.
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  • An Online Cluster Anomaly Job Prediction Method
  • XIE Li-xia, WANG Zi-ying
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 62-68. DOI:10.13190/j.jbupt.2018-308
  • Abstract ( 476 )     HTML     　　
  • An online cluster anomaly job prediction method (OCAJP) is proposed. Firstly, a calculation of dynamic features of sub-tasks in the job was designed. Secondly, an improved gated recurrent unit (IGRU) neural network was designed according to the dynamic features. Then, the IGRU was used to predict whether the sub-task's final status was abnormal according to its dynamic features. Finally, the anomaly job was obtained based on the status relevance between the job and its sub-tasks, so as to complete prediction of abnormal jobs. The experimental results showed that OCAJP had a significant improvement in prediction sensitivity, error rate, accuracy, and prediction time compared with other prediction methods; this method had applicability in protecting the security of the cluster platform.
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  • Research on Identity-Based Batch Anonymous Authentication Scheme for Vehicular Network
  • SONG Cheng, GU Xin-an, WANG Lei, LIU Zhi-zhong, YAN Xi-xi
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 69-74. DOI:10.13190/j.jbupt.2018-274
  • Abstract ( 416 )     HTML     　　
  • For the security and efficiency of anonymous authentication in vehicular networks, an identity-based anonymous authentication scheme for vehicular networks is proposed by using bilinear pairing theory. The security of the scheme is further enhanced and the load of the trusted center is reduced by collaborating between the tamper-proof device of the onboard unit and the trusted center, the efficiency of the anonymous authentication of the onboard network is improved by batch verification. Security and efficiency analysis show that the scheme not only satisfies the security characteristics of anonymity, unforgeability and non-repudiation, but also has better time complexity and space complexity. The simulation results show that the scheme has certain advantages in both effectiveness and feasibility.
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  • Construction of Group Repairable Codes for Non-Uniform Fault Protection
  • WANG Jing, LIU Yan, YU Chun-lei, WANG Mi, LIU Xiang-yang
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 75-82. DOI:10.13190/j.jbupt.2019-026
  • Abstract ( 429 )     HTML     　　
  • Considering that there are files with different heat in actual distributed storage systems, a class of group repairable codes based on non-uniform fault protection (GRC-NFP) is proposed. GRC-NFP provides higher protection for hot files and nodes with high fault probability, and reduces the disk I/O overhead for repairing multiple failed nodes. Specifically, after hot and cold grouping, the fault probabilities of data blocks are represented and sorted by that of the stored target nodes. Data blocks are stored into multiple data groups with increasing lengths, and group encoded blocks are further generated. Performance analysis and actual system deployment showed that GRC-NFP had higher fault tolerance and lower repair locality under less storage overhead compared with Reed-Solomon codes and group repairable codes. Moreover, the hot files can be protected more effectively by adopting GRC-NFP. The fewer coding and fault repair time under system deployment further proved the feasibility of GRC-NFP.
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  • Research and Implementation of Triangle Mesh Parameterization Method Based on Barycentric Mapping
  • GUAN Yan-ran, Oliver van Kaick, GUAN You-qing
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 83-90. DOI:10.13190/j.jbupt.2018-266
  • Abstract ( 716 )     HTML     　　
  • The parameterization of triangle meshes has numerous applications in the field of geometry processing. Using the halfedge-based data structure provided by geometry-processing-js, this paper researches on the mesh parameterization and its implementation based on barycentric mapping, as well as three weight sets applied in barycentric mapping, namely, the uniform Laplacian weights, the Laplace-Beltrami weights, and the mean value weights. A comparison between the results of parameterization is given based on the distortion caused to the triangles, and a conclusion is given that the mean value weights provide the best weighting scheme for barycentric mapping.
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  • Static Vulnerability Detection Technology for the Embedded Firmware Web Code Based on D-S Evidence Theory
  • WANG Si-qi, MIAO Si-wei, ZHANG Xiao-ling, SHI Zhi-qiang, LU Xin-dai
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 91-99. DOI:10.13190/j.jbupt.2018-212
  • Abstract ( 308 )     HTML     　　
  • Currently, vulnerabilities mining and detection for firmware mainly include dynamic analysis which based on virtual simulation and static auditing which based on reverse engineering. These techniques may have low simulation rate and high false positive rate. Proposing a method based on multi-dimensional features for detection of firmware web vulnerabilities. This method can detect common Web vulnerabilities in firmware effectively and lower the false positive rate by using multi-dimensional features, multi-level preprocessing and vulnerabilities reasoning models based on D-S evidence theory.
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  • The Zero Watermarking Algorithm Based on Distance Partition for BIM Modeling
  • JING Min, REN Na, ZHU Chang-qing, ZHOU Zi-chen
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 100-106. DOI:10.13190/j.jbupt.2019-027
  • Abstract ( 473 )     HTML     　　
  • Aiming at the building information modeling (BIM) model copyright problem, basing on the BIM data characteristics, designs a zero watermarking algorithm for BIM data, which will not change data precision. Because different modeling has its own primitives and constraint relation, the proposed algorithm must be taking full account of the difference. Firstly, the lowly constraints of the primitive points are removing and the other primitive location points are obtaining. The distance between each point benchmark and the feature point is the carrier for watermarking by choosing the feature point of the monomer precise modeling. Secondly, the algorithm bubbles sort the eigenvalues and obtains the change rate of consecutive eigenvalues, then removing the high change rate eigenvalues. Finally, dividing the eigenvalues and construct a series of zero watermarking sequence. The results of experiment showed that the algorithm had strong robustness to usual attacking such as translation, rotation and slightly deleting point.
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  • Path Planning Based on Energy Constraints of Mars Rover
  • LIU Tao, TANG Ling, YUAN Bao-feng, WEI Shi-min
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 107-112. DOI:10.13190/j.jbupt.2019-025
  • Abstract ( 656 )     HTML     　　
  • Aiming at the excessive energy consumption of Mars rover on Mars, a path planning algorithm based on energy constraints is proposed. Firstly, considering overcoming gravity work and internal loss of driving mechanism, the motion energy consumption function of Mars rover is deduced, and its minimum value is solved. Therefore, the energy weighted map is constructed. Then, the energy consumption minimal path of the energy weighted graph is calculated by Dijkstra algorithm and using quintic polynomial interpolation to realize trajectory planning. Finally, Adams is used to establish the typical terrain of Mars and dynamics model of Mars rover, and Matlab/Simulink is used to build the controller model of Mars rover. The dynamics and control simulation of Mars rover in typical environment is used to verify the effectiveness of the path planning algorithm. The results show that compared with the traditional avoidance algorithm, the energy consumption of Mars rover is reduced by more than 15% using the proposed path planning algorithm, which can effectively improve the energy utilization efficiency of Mars rover.
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  • Node Localization Algorithm of Wireless Sensor Networks for Complex Terrain in Mountain Areas
  • HU Zhong-dong, WANG Jun-ling, WANG Zhen-dong, ZENG Ting
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 113-118. DOI:10.13190/j.jbupt.2019-019
  • Abstract ( 516 )     HTML     　　
  • Aiming at the problem that the non-ranging three-dimensional distance vector based localization algorithm has a large positioning error in mountainous terrain, a wireless sensor network node localization algorithm (NLA-MT) is proposed. The algorithm effectively utilizes the characteristics of the mountainous terrain environment and uses the local plane to fit the surface of the mountainous terrain. The three-dimensional spatial positioning operation is reduced to a two-dimensional plane positioning operation to perform node positioning, which effectively improves the positioning accuracy of the node. The multi-angle simulation experiments with different communication radius, different anchor node ratios and different total nodes show that the NLA-MT localization algorithm performs well in mountainous terrain scenes. The accuracy of the non-ranging positioning algorithm of the wireless sensor network is effectively improved.
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  • Automatic Segmentation of Workpiece Based on Target Morphological Features
  • PANG Zeng-zhi, SHI Jian-jie, YIN Jian-qin, ZHU Li-min, LI Jin-ping
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 119-126. DOI:10.13190/j.jbupt.2018-309
  • Abstract ( 444 )     HTML     　　
  • Since many enterprises produce a huge number of workpiece images every day, and the existing interactive workpiece segmentation algorithm can not meet the real-time requirements, a workpiece segmentation method combining workpiece morphological features and image segmentation algorithm is proposed. This method consists of four steps:firstly, the image is segmented by use of MeanShift algorithm to extract the target region; secondly, the noise in the target region is eliminated using morphological open operation, and then the connected target region can be separated; thirdly, the edge detection of the target region is carried out to calculate the complete workpiece contour information, and then the workpiece region is determined according to the size of the outer contour area; fourthly, the foreground and background regions are labeled by using the minimal contour rectangle of the workpiece area and the Gaussian mixture model is established using GrabCut algorithm for foreground and background respectively, then the foreground and background regions can be segmented by use of mincut/maxflow algorithm, and finally the workpiece object can be extracted. The experimental results show that, for the samples provided by the manufacturer, the recall and accuracy of the proposed method are 94.97% and 88.48% respectively, and the method has strong practicability and good real-time performance.
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  • Flattop Broadband Wavelength Converters Based on Cascaded Sum+Difference Frequency Generation
  • LIU Tao, SUN Chun-yang, ZHU Cong, WANG Ping-ping, FANG Xin-xin
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 127-132. DOI:10.13190/j.jbupt.2018-311
  • Abstract ( 550 )     HTML     　　
  • In order to improve the conversion characteristics of wavelength converters,the effect of the segmented quasi-phase matched grating structure in the periodically poled lithium niobate crystal on the characteristics of wavelength converters based on cascaded sum + difference frequency generation is studied. For both of single-pass and double-pass configurations, high conversion efficiency, large conversion bandwidth, and good flatness can be achieved simultaneously by increasing the number of segments and optimizing the poling period of each segment. Under the same conditions, the conversion efficiency and flatness of the double-pass configuration are better, but the conversion bandwidth is slightly worse than that of the single-pass configuration. Compared with the method of shifting the wavelength of one of the pump light, the use of segmented quasi-phase matched grating structure in wavelength converter can obtain almost the same flatness but better conversion efficiency and conversion bandwidth. Moreover, the effect of crystal length on the characteristics of a wavelength converter based on the segmented quasi-phase matched grating structure is also investigated.
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  • A Low-Complexity Detection Algorithm Based on Relaxation Iteration Method for GSM-MBM Systems
  • JIN Ning, SONG Wei-jing, JIN Xiao-ping, CHEN Dong-xiao, XU Ling-jing
  • Journal of Beijing University of Posts and Telecommunications. 2019, 42(5): 133-138. DOI:10.13190/j.jbupt.2018-302
  • Abstract ( 232 )     HTML     　　
  • The complexity of the maximum likelihood (ML) detector of the generalized spatial modulation-media based modulation system is very high and exponentially grows with the number of active antennas. A low-complexity detection algorithm termed energy ordered-relaxation iteration method (EO-RIM) is proposed. First, the possible active transmit antenna combinations and corresponding mirror activation pattern combinations are sorted according to their signal energy, then a relaxation iterative method is performed to obtain corresponding modulated signals. According to a predefined threshold, the algorithm strikes a trade-off between complexity and performance. Simulations show that the bit error ratio performance of EO-RIM algorithm approaches that of ML detection algorithm and is comparable to that of the ordered block minimum mean squared error detection algorithm. The computational complexity of EO-RIM grows with the square of the number of active antennas, while ML detector has exponential complexity.
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