最新刊期
卷 33 ， 期 8 ， 2017
- 摘要：A brief introduction was given to the development history of AVS video coding standards.Then an overview of the key technologies adopted in AVS2 video coding standard (GB/T 33475.2-2016) was provided,including flexible prediction partition,multiple hypothesis prediction,optimized two-level transform,adaptive loop filter and background picture model based prediction coding for scene video.Compared to the AVS1,AVS2 can achieve more than 50% bits saving.And compared to HEVC/H.265,AVS2 can achieve significant coding efficiency improvement for scene video coding.Moreover,the applications of AVS standard in digital TV broadcasting was introduced briefly.关键词：AVS;transform;prediction;entropy coding;loop filter1344|2349|0更新时间：2024-06-05
- 摘要：The current video coding uses block based hybrid architecture,which uses predictive,transform,quantization and entropy coding techniques to efficiently compress video signals.Further optimizations on current architectures provide more flexible processing and coding for local characteristics of video image signals.Video coding based on machine learning was expected to change the existing hybrid coding framework partially or comprehensively,and bring new research ideas to video coding.In addition to existing 2D video signal,the future of video also needs to spherical video coding and volumetric video coding for AR/VR applications,the new video source data format of the video encoding technology has brought new opportunities and challenges.关键词：video coding;machine learning;virtual reality;spherical video;volumetric video1622|2245|0更新时间：2024-06-05
- 摘要：The next generation video coding standard HEVC(high efficiency video coding) and AVS2 have been developed.The key technologies of video coding were surveyed,specifically including coding unit,intra-prediction,inter-prediction and de-blocking filter.Besides that,the new development directions were analyzed and discussed,such as scene video coding,cloud coding,deep learning video coding,and so on.关键词：video coding;HEVC;AVS2863|2391|0更新时间：2024-06-05
- 摘要：TPG(tiny portable graphic) is a new image compression technology based on the video part of AVS2 standard,whose compression efficiency is notably higher than traditional image formats like JPG,PNG and GIF.Theory and feature of TPG image compression technology were introduced.Then,the compression efficiency of TPG and traditional image formats was compared.Results show that TPG has overwhelming advantage.关键词：tiny portable graphic;AVS2;image compression1229|1452|0更新时间：2024-06-05
- 摘要：Virtual reality is a hot topic in the field of video.The current situation of VR video content production and VR video display technology was introduced,and the key technologies of viewport dependent VR video processing were analyzed.Finally,the mechanisms of VR video streaming and corresponding network requirements were discussed.关键词：virtual reality;virtual reality video;projection;region-wise packing;viewport dependent video coding;omnidirectional video streaming1134|1588|0更新时间：2024-06-05
- 摘要：For the limitations of existing IPTV system in personal service,interactive service,the existing and developing dynamic media packaging technologies were studied.In order to make dynamic media packaging technologies easy to apply in the IPTV system,a method that adding the label information to the source for MPEG-2 standard encoding was proposed,and TS package technology was used to transmit,and finally decoding was achieved by the decoder.This technology had been used in realizing the system of nine screens hottest business system and had achieved practical application.关键词：internet protocol television;dynamic media;label encoding personality709|1181|0更新时间：2024-06-05
- 摘要：MPEG2-TS VBR coding technology is widely used,but the traditional MDI-DF-based algorithm is not suitable for detecting the transmission quality of VBR stream.The MPEG2-TS VBR stream quality evaluation algorithm was proposed.By monitoring the PCR field of MPEG2-TS stream,the absolute amount of playback time and unit time of VBR video stream received in unit time was calculated.VBR video streaming quality was evaluated according to the absolute deviation.Experimental results show that the proposed algorithm is feasible and effective.关键词：video stream;MPEG2-TS;variable bit rate;quality monitoring;content delivery685|1102|0更新时间：2024-06-05
- 摘要：As videos becoming the major sources of acquiring information in current era,consumers have raised their expectations for video quality experience,which has become the most critical competitiveness for video service providers.A thorough review of quality of experience (QoE) was presented,and then detailed analysis of video QoE and relevant no reference assessment methods were provided.Further,the standardization process of video QoE in China and the evaluation results of Chinese video services quality were introduced.Last but not the least,the characteristics of Chinese video services was summarized and advices of improvement were presented.关键词：quality of experience;video service;no reference video quality assessment991|1751|0更新时间：2024-06-05
Topic:theory and practice of video technology
- 摘要：The two-stage hybrid beamforming architecture can solve the problem of limited number of RF chains effectively.However,it is still difficult to design a hybrid beamforming algorithm with better performance.In order to achieve higher spectral efficiency,an alternating minimum mean square error (Alt-MMSE) hybrid beamforming algorithm was proposed.Firstly,the initial digital matrix by using the orthogonal properties of the digital matrix was designed,and then the digital matrix by minimizing the square error of the transmitted signal and the received signal was updated.During each iteration,the phase of the analog matrix could be obtained from the updated digital matrix and the optimal fully digital matrix.The simulation results show that the proposed algorithm has better performance and is closer to fully digital beamforming than OMP hybrid beamforming algorithm and hybrid processing scheme based on matrix decomposition .关键词：mmWave MIMO;minimum mean square error;hybrid beamforming;RF chain1069|1303|0更新时间：2024-06-05
- 摘要：ISM (industrial scientific and medical) bands where wireless sensor network works faced with the shortage of spectrum resources problems.Aimed at this case,dynamic spectrum allocation in cognitive radio technology was applied in wireless sensor network.A dynamic frequency spectrum allocation scheme was proposed.The algorithm was a modified adaptive genetic algorithm which was based on graph coloring model.In addition,the objective functions of the algorithm were maximum bandwidth gains and minimum spectrum handoff,besides,in the crossover and mutation process,adaptive crossover probability and mutation probability was used instead of the fixed.Experimental results confirm that compared with the traditional genetic algorithm and color sensitive graph coloring algorithm,the proposed algorithm can achieve the expected goal of improving the spectral efficiency and reducing energy consumption.关键词：cognitive radio sensor network;genetic algorithm;graph coloring;dynamic spectrum allocation653|673|0更新时间：2024-06-05
- 摘要：Mobility management (MM) is a vital part of future 5G mobile communication.How to balance the paging loads and reduce the location update costs is a key topic in wireless communication research.A novel model of group mobility management based on user behavior prediction was proposed,in which users with the similar moving characteristics could be under unified management,thereby repeated costs from the traditional model of single mobility management (SMM) could be reduced.Simulation results show that GMM can get better running cost than SMM.关键词：group mobility management;user behavior prediction;centroid aiming model;paging cost730|998|0更新时间：2024-06-05
- 摘要：Energy efficiency based PUEA defensive scheme was investigated with performance analysis.In this scheme,CSS energy efficiency was constructed as the optimum objective in the presence of PUEA with secure detection probability and false alarm probability threshold as the constraint conditions.Secure CSS model and PUEA defensive scheme were proposed to achieve energy efficiency based secure CSS.K-out-of-N criterion is set as global decision criterion in the scheme.Optimal fusion threshold K and optimal cooperative SUs N can be determined in secure CSS with the guarantee of energy efficiency.Compared with the traditional maximum ratio combining (MRC) fusion rule,the proposed PUEA defensive scheme not only guarantees system energy efficiency,but also improves system detection performance.Namely,the proposed scheme makes a trade-off between energy efficiency and detection performance in the presence of PUEA.The numerical simulation results show that the proposed strategy is not affected by the PUE interference power,and it has a high degree of persistence for PUEA attack.关键词：cognitive radio network;primary user emulation attack;defensive scheme;energy efficiency;detection performance387|686|0更新时间：2024-06-05
- 摘要：Cognitive wireless sensor network (CRSN) is a new type of network that introduces cognitive radio (CR) technology into traditional WSN,and has certain application value and developmental prospect.However,the additional energy consumption,processing requirements and its high cost implementation have hindered its further development and application.Based on this,transfering cognitive functions to another nodes——cognitive nodes which have ability of processing and collecting energy was proposed.The cognitive nodes were deployed with the ordinary sensor nodes according to the certain proportion.They form a new type of network——heterogeneous node CRSN (HT-CRSN).The new network can improve network performance and reduce the deployment cost.Then a work schedule which can be applied to this kind of heterogeneous node sensor networks and a series of feasible MAC protocols was proposed.The analysis of the proposed MAC protocol proves that energy consumption can be balanced by adjusting the deployed ratio of the two kinds of heterogeneous nodes and the network life cycle is improved.关键词：wireless sensor network;cognitive wireless sensor network;heterogeneous node;work schedule;MAC protocol352|1077|0更新时间：2024-06-05
- 摘要：Aiming at the problem of tamper detection of composite image of natural images and highly simulated computer-generated images,a method of extracting image block color and texture feature based on differential histogram and local binary texture descriptor in YCbCr color space was proposed.By training posterior probability support vector machine,the image block to be measured was identified.In the case of non-overlapping block,the approximate tampering area was general judged,then the block was discriminated by pixel in the region,ultimately the accurate location of tampering area was achieved.The experimental results show that the recognition rate of 128 dpi×128 dpi image blocks is 94.75%,which is higher than other methods.The tapering region of the synthesized image can be precisely positioned,and the rotation and scaling operation show good coercivity.关键词：composite image;feature extraction;posterior probability support vector machine;tampering detection1076|770|0更新时间：2024-06-05
- 摘要：The network slicing is an important technology for 5G to implement the on-demand networking based on SDN/NFV network architecture.According to the main scene of 5G,a network segmentation algorithm based on GA-PSO was proposed in SDN/NFV architecture.The merit of quick converging to the global optimal solution was used to design the evaluation function of the network slicing.Using the ability of the fast random search of genetic algorithm,the updating and optimization of the network slices could be realized by using the particle swarm to chase the local optimal solution and the global optimal solution.The simulation results show that the algorithm can realize the personalized creation of multi-service scene network slices,and give full play to the advantages of SDN centralized control mode.It can reduce the energy consumption of the network and improve the utilization rate of cyber source at the same time.关键词：5G;network slicing;genetic algorithm-particle swarm optimization;orchestration892|1977|0更新时间：2024-06-05
- 摘要：Sparse code multiple access (SCMA) is a type of code domain non-orthogonal multiple access technology,which is regarded as a promising multiple access technology for 5G due to its excellent performance.The uplink SCMA system generally uses a message passing algorithm (MPA) in the receiver.The priori information can be inaccurated to cause an increased detection error.A novel receiver for the uplink SCMA system,called ring-MPA (R-MPA) receiver,was proposed to solve this problem,by using a joint detection process.The proposed R-MPA receiver was compared with the log-MPA receiver and the classic MPA receiver,two state-of-the-art existing schemes.Both theoretical analysis and computer simulation results show that the proposed receiver not only has a superior error performance,but also has a lower implementation complexity than these existing schemes.关键词：5G;sparse code multiple access;message passing algorithm;R-MPA;overloading factor421|680|0更新时间：2024-06-05
- 摘要：Due to a high similarity between the recaptured voice recorded by high-fidelity ripping equipment and the original voice,the automatic speaker verification（ASV）system used to be attacked illegally by the recaptured voice.In order to improve the ability of resisting the attack,a recaptured voice detection method was proposed based on the difference of phase spectrum between original and recaptured voices for the ASV system.In addition,the effects of different recording and replay devices,the FFT were discussed.Experimental results show that the proposed method can accurately recognize the recording voice,of which detection rate is 99.04%。Meanwhile,the equal error rate (EER) of the ASV system has dropped about 22% with this method being integrated,which indicates that the system’s ability of resisting playback attack is enhanced.关键词：ASV system;recaptured voice detection;phase spectrum406|997|0更新时间：2024-06-05
research and development
- 摘要：Location services based on mobile signaling data analysis and base station positioning services are two different user location services.One is the real-time positioning service; the other is the location service based on historical signaling data analysis,and they all have their own advantages and disadvantages.Some technical solutions that combined the base station real-time positioning with the open capability of mobile signaling data analysis based on historical trajectory and regional population statistics were presented,and the implementation of these methods were described in detail.A new idea for telecom operators to open and optimize their location capability based on network signaling was provided.关键词：mobile network;signaling data analysis;location service;positioning679|1544|0更新时间：2024-06-05
- 摘要：Near field communication (NFC) is a kind of short-range wireless communication technology which has been applied around the world.The applications of mobile payments and access control are the most common applications of NFC technology.Technically,the NFC device can be used as a bank card or an entrance card with the help of the card emulation mode of NFC,which will be validated by external reader.It is very essential to select a appropriate and safe certification scheme in this scenario.First of all,the existing NFC authentication system and security scheme was introduced and the system security requirements and potential security risks were analyzed.Then,by using Hash,AES and password Key dynamic updating mechanism,a mutual authentication security scheme for mobile NFC devices was proposed,and the synchronization mechanism was designd.Finally,GNY logic was used to prove the security correctness of our proposed scheme.The security analysis shows that our scheme can avoid a number of attacks,such as forgery,replay attack,eavesdropping,tampering attack,asynchronous attack and so on.关键词：near field communication;mutual authentication;security;mobile device482|1228|0更新时间：2024-06-05
- 摘要：Considering of the characteristics such as small amount data of single communication terminal node and large scale distribution of terminal nodes,the strategy of network planning should increase the number of access nodes and maximize the capacity of the network.In the macro and micro base station deployment,the macro base station and the micro base station were simultaneously deployed to provide more deployment options for the micro base station.Based on the analysis of the demand of smart distribution network communication services and the drawbacks of the existing network planning,a multi-objective optimization model was established and a single objective optimization model was established for comparative analysis.Finally,the superiority of the strategy was proved from the scheme diagram and network performance analysis.关键词：smart distribution network;heterogeneous wireless network;network planning317|786|0更新时间：2024-06-05
- 摘要：With the arrival of large data age,data has become the most valuable resource.And web crawler technology as an important means of external data collection,has become a standard tool for data analysis.A high-performance,convenient cloud-based crawler architecture design was introduced.The overall structure of the reptile to the distributed design and the design of the sub-module was described in detail.Each module of the crawler was encapsulated in Docker,and Kubernetes was used as the resource scheduling and management of the cluster.In the performance of optimization,the MD5 reset tree algorithm,DNS optimization and asynchronous I/O were adopted.Experimental results show that the performance of crawler has obvious advantages compared with the UN optimized scheme.关键词：distributed system architecture;web crawler;Docker;high-performance496|1268|0更新时间：2024-06-05
- 摘要：2015 is the year when “the 12th Five-year Plan” fully completed,and “the 13th Five-year Plan” starts.To discover problems,judge trends and solve problems are the top priorities in the first year of planning.According to“Global Information Technology Report 2015”that released by World Economic Forum,China is also facing three weaknesses,such as the low per capita internet bandwidth,the limited mobile broadband penetration and the urgent need of innovation environment.Situation analysis and international comparison were presented,and policy recommendations were given from three major aspects,such as improving broadband capabilities,developing Aerospace integrated networks and innovative application environments，which break down into six sub-directions such as domestic broadband networks,international network layout,mobile communications,space infrastructure,application infrastructure and software-defined network.关键词：national information infrastructure;international comparison analysis;policy recommendation509|1116|0更新时间：2024-06-05
- 摘要：After more than ten years of development and construction,the electric power industry has achieved remarkable results.Information integration of the company's production,operation and management of various fields,strongly promote the transformation of development of the company and power production.Informatization has become the key driving force to promote the production of electric power safety,customer service,scheduling and control,and gradually realize the transformation of enterprise information to the information enterprise.Based on the current situation of electric power enterprise information construction,the core elements of the evaluation system of the electric power industry informatization enterprise were studied,and the framework of information enterprise evaluation system was put forward.关键词：informationization-based enterprise;evaluation system;core element395|1222|0更新时间：2024-06-05
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