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991.
移动网络结构日趋复杂,网络场景多样化,影响用户体验的因素也越来越难以判断。结合SEQ平台系统,通过调整上行调度算法参数中"上行HARQ最大传输次数"参数,增大UE配置的最大传输次数,提高数据包传输成功率,降低信道编码率,提高解码效果,以降低HTTP页面打开时延。通过试验区优化验证,该措施能有效降低HTTP页面的各项时延。 相似文献
992.
Encrypted traffic classification plays a vital role in cybersecurity as network traffic encryption becomes prevalent. First, we briefly introduce three traffic encryption mechanisms: IPsec, SSL/TLS, and SRTP. After evaluating the performances of support vector machine, random forest, naïve Bayes, and logistic regression for traffic classification, we propose the combined approach of entropy estimation and artificial neural networks. First, network traffic is classified as encrypted or plaintext with entropy estimation. Encrypted traffic is then further classified using neural networks. We propose using traffic packet’s sizes, packet's inter‐arrival time, and direction as the neural network's input. Our combined approach was evaluated with the dataset obtained from the Canadian Institute for Cybersecurity. Results show an improved precision (from 1 to 7 percentage points), and some application classification metrics improved nearly by 30 percentage points. 相似文献
993.
Jiang Yi Wang Jinjin Shi Jieke Zhu Junwu Teng Ling 《Mobile Networks and Applications》2020,25(4):1457-1468
Mobile Networks and Applications - As a key technology of cloud computing, virtualization technology enables multiple virtual machines (VMs) to run on a host to meet the operational needs and... 相似文献
994.
Peigen Li Teng Ding Junqin Li Chunxiao Zhang Yubo Dou Yu Li Lipeng Hu Fusheng Liu Chaohua Zhang 《Advanced functional materials》2020,30(15)
Because the intrinsic Ge vacancies in GeTe usually lead to high hole concentration beyond the optimal range, many previous studies tend to consider Ge vacancies as negative effects on increasing the figure of merit ZT of GeTe‐based alloys, and consequently have proposed various approaches to suppress Ge vacancies. However, in this work, it is demonstrated that the Ge vacancies can have great positive effects on enhancing the ZT of GeTe‐based alloys when the hole concentration falls into the optimal range. First, hole concentration of GeTe is reduced close to the optimal range by co‐alloying of Pb and Bi, and then the Ge vacancies are increased by adding excess Te into the Ge0.8Pb0.1Bi0.1Te1+x. The Ge vacancies can cause lattice shrinkage and promote rhombohedral‐to‐cubic phase transition. As revealed by first‐principle calculations, theoretical simulations, and experimental tests, Ge vacancies can facilitate the band convergence, suppress the bipolar transport at higher temperature range, and reduce the lattice thermal conductivity. Combining these effects, a peak ZT of 1.92 at 637 K and an average ZT of 1.34 within 300–773 K in Ge0.8Pb0.1Bi0.1Te1.06 can be obtained, demonstrating the great significance of utilizing vacancy‐type defects for enhancing ZT. 相似文献
995.
Xizheng Wang Zhenqian Pang Chaoji Chen Qinqin Xia Yubing Zhou Shuangshuang Jing Ruiliu Wang Upamanyu Ray Wentao Gan Claire Li Gegu Chen Bob Foster Teng Li Liangbing Hu 《Advanced functional materials》2020,30(22)
Among all the plastic pollution, straws have brought particularly intricate problems since they are single use, consumed in a large volume, cannot be recycled in most places, and can never be fully degraded. To solve this problem, replacements for plastic straws are being developed following with the global trend of plastic straw bans. Nevertheless, none of the available degradable alternatives are satisfactory due to drawbacks including poor natural degradability, high cost, low mechanical performance, and poor water stability. Here, all‐natural degradable straws are designed by hybridizing cellulose nanofibers and microfibers in a binder‐free manner. Straws are fabricated by rolling up the wet hybrid film and sealed by the internal hydrogen bonding formed among the cellulose fibers after drying. The cellulose hybrid straws show exceptional behaviors including 1) excellent mechanical performance (high tensile strength of ≈70 MPa and high ductility with a fracture strain of 12.7%), 2) sufficient hydrostability (10× wet mechanical strength compared to commercial paper straw), 3) low cost, and 4) high natural degradability. Given the low‐cost raw materials, the binder‐free hybrid design based on cellulose structure can potentially be a suitable solution to solve the environmental challenges brought by the enormous usage of plastics straws. 相似文献
996.
Multimedia Tools and Applications - In High Efficiency Video Coding (HEVC), the coding efficiency of intra frames is much lower than inter frames. If the bits allocated to intra frames are not... 相似文献
997.
998.
热电材料利用Seebeck与Peltier效应可以实现热能和电能的相互转化,是颇具潜力的新型功能材料.本文聚焦四元硫属化合物Cu2B^ⅡC^ⅣSe4(其中, B位为Zn, Cd, Mn, Hg, C位为Si, Ge, Sn)的热电性能.此类材料具有复杂的晶格结构,导致其具有较低的晶格热导率,是一类具有本征低热导的热电材料.本文系统地总结了各类优化四元硫属化合物电学及热学的方法.首先,非化学计量法、元素掺杂和η=1定理用于改善其电学性能.然后,纳米结构工程可用于进一步降低其热导率.最后,基于文中的论述,我们提出通过多种实验方法的结合使用,协同调控四元硫属化合物的电、热性能,以期进一步提高其热电性能. 相似文献
999.
Longqing Tang Guowei Bo Fulin Jiang Shiwei Xu Jie Teng Dingfa Fu Hui Zhang 《材料科学技术学报》2021,75(16):184-195
The precipitation evolutions of Mg-Al-Zn alloys play essential roles in their mechanical properties,corro-sion performance,formability,plastic deformation mechanisms and texture development.In the present work,the precipitation evolutions of AZ80 magnesium alloy during both non-isothermal and isothermal processes were unraveled by utilizing in situ electrical resistivity monitoring,hardness testing,differen-tial scanning calorimetry and microstructural characterization.The results showed that discontinuous precipitation(DP)and continuous precipitation(CP)occurred competitively during non-isothermal and isothermal processes.The precipitation of dominant 3-Mgi7Ali2 phase during non-isothermal processes was highly dependent on the thermal history.During isothermal processes,the precipitation behavior of AZ80 magnesium alloy could be considered as the functions of holding temperature and time.At lower temperatures,massive DP and CP were gradually formed to equally strengthen the alloy.At higher tem-peratures,the Ostwald coarsening was characterized in the later stages and indicated to slightly soften the alloy.Isothermal time-temperature-precipitation curves and quantitative precipitate evolution were estimated to unravel precipitation characteristics and their strengthening functions. 相似文献
1000.
Teng‐Sing Wei Bok Yeop Ahn Julia Grotto Jennifer A. Lewis 《Advanced materials (Deerfield Beach, Fla.)》2018,30(16)
The growing demand for rechargeable lithium‐ion batteries (LIBs) with higher capacity in customized geometries underscores the need for new battery materials, architectures, and assembly strategies. Here, the design, fabrication, and electrochemical performance of fully 3D printed LIBs composed of thick semisolid electrodes that exhibit high areal capacity are reported. Specifically, semisolid cathode and anode inks, as well as UV curable packaging and separator inks for direct writing of LIBs in arbitrary geometries are created. These fully 3D printed and packaged LIBs, which are encased between two glassy carbon current collectors, deliver an areal capacity of 4.45 mAh cm?2 at a current density of 0.14 mA cm?2, which is equivalent to 17.3 Ah L?1. The ability to produce high‐performance LIBs in customized form factors opens new avenues for integrating batteries directly within 3D printed objects. 相似文献