Energy-Efficient Optimization for Energy-Harvesting-Enabled mmWave-UAV Heterogeneous Networks

Energy Harvesting (EH) is a promising paradigm for 5G heterogeneous communication. EH-enabled Device-to-Device (D2D) communication can assist devices in overcoming the disadvantage of limited battery capacity and improving the Energy Efficiency (EE) by performing EH from ambient wireless signals. Although numerous research works have been conducted on EH-based D2D communication scenarios, the feature of EH-based D2D communication underlying Air-to-Ground (A2G) millimeter-Wave (mmWave) networks has not been fully studied. In this paper, we considered a scenario where multiple Unmanned Aerial Vehicles (UAVs) are deployed to provide energy for D2D Users (DUs) and data transmission for Cellular Users (CUs). We aimed to improve the network EE of EH-enabled D2D communications while reducing the time complexity of beam alignment for mmWave-enabled D2D Users (DUs). We considered a scenario where multiple EH-enabled DUs and CUs coexist, sharing the full mmWave frequency band and adopting high-directive beams for transmitting. To improve the network EE, we propose a joint beamwidth selection, power control, and EH time ratio optimization algorithm for DUs based on alternating optimization. We iteratively optimized one of the three variables, fixing the other two. During each iteration, we first used a game-theoretic approach to adjust the beamwidths of DUs to achieve the sub-optimal EE. Then, the problem with regard to power optimization was solved by the Dinkelbach method and Successive Convex Approximation (SCA). Finally, we performed the optimization of the EH time ratio using linear fractional programming to further increase the EE. By performing extensive simulation experiments, we validated the convergence and effectiveness of our algorithm. The results showed that our proposed algorithm outperformed the fixed beamwidth and fixed power strategy and could closely approach the performance of exhaustive search, particle swarm optimization, and the genetic algorithm, but with a much reduced time complexity.     

不同形貌Sb2O3的控制合成及其光催化性能研究

采用醇解法与水热法制备了Sb2O3光催化材料,研究了制备条件对Sb2O3晶型、形貌及催化性能的影响.结果表明,以PEG-400为表面活性剂、反应体系pH=7时,通过醇解法制得的立方晶型、呈球形颗粒状的Sb2O3催化性能最佳,在紫外光照180 min时,对10.0 mg/L罗丹明B的降解率达到了96.8;;对20.0 mg/L左氧氟沙星降解率为66.3;;对10.0 mg/L磺胺吡啶降解率为46.2;.当反应温度为160℃,反应时间为12 h时,由水热法制得的斜方晶型、呈枕头状的Sb2O3催化性能较差,在紫外光照射180 min时,对10.0 mg/L罗丹明B的降解率为57;.     

分类问题的在线顺序双并联快速学习机

双并联前馈神经网络模型是单层感知机和单隐层前馈神经网络的混合结构,本文构造了一种双并联快速学习机算法,与其他类似算法比较,提出的算法能利用较少的隐层单元及更少的待定参数,获得近似的学习性能.数值实验表明,对很多实际分类问题,提出的算法具备更佳的泛化能力,因而可以作为快速学习机算法的有益补充.     

氯酸钠氧化法制备超细氧化铁黄的研究

利用氯酸钠氧化硫酸亚铁工艺制备超细氧化铁黄,制备过程中采用低成本的氨水合成氢氧化铁。制备过程包括亚铁盐水溶液的氧化、氢氧化铁胶体的合成和转化以及产物的表面处理。产物是分布在长100～230 nm,宽15～30 nm范围的针状粒子。通过X-射线衍射鉴别晶相,利用X-射线衍射和透射电镜测定产物的粒径,考察了反应温度等多种因素对样品的色相和粒径的影响。     

相位敏感OTDR和布里渊OTDR结合的双参量分布式光纤传感的研究

在分布式光纤传感及应用中,单一传感系统一般只能实现一种参量的监测,如相位敏感光时域反射计(Φ-OTDR)只能监测光纤沿线的振动信息,布里渊光时域反射计(BOTDR)仅能监测应变/温度信息.对于多参量监测的应用场合,必须通过配合多种技术和系统来实现多参量监测和分析,增加监测成本和复杂性.设计并搭建了一种集成Φ-OTDR和...     

速率光纤陀螺寻北仪倾斜补偿算法研究

针对速率光纤陀螺寻北仪,提出了一种倾斜补偿算法.通过采用积分滑动和最小二乘拟合滤波技术,对光纤陀螺和加速度计原始测量信号进行数据处理.试验数据表明,采用本算法解决了由倾斜角存在影响其寻北准确度的关键技术问题.同时给出了提高光纤陀螺寻北仪的准确度的可能因素.     

热处理对氧化铋在8μm～14μm波段内的发射率的影响

本文通过设计正交实验,采用不同的热处理工艺对着色颜料氧化铋粉末进行热处理,随后测量样品在8μm～14μm波段的平均法向发射率,并得出优化的热处理工艺路线;对各个影响因素进行的分析表明,温度是热处理过程中影响样品发射率变化的主要因素,并通过XRD、SEM、EDS等多种表征手段,分析了红外发射率变化的内在机理.结果表明,晶格畸变是引起发射率变化的主要因素,而由气体分子吸附引起的表面成分变化对发射率也有一定的影响.     

Selected-Mapping Peak-to-Average Power Reduction Method with Orthogonal Pilot Sequences in Underwater Acoustic OFDM System Without Side Information

A novel Selected-mapping (SLM) Peak-to-average power ratio (PAPR) reduction scheme requires no Side information (SI) in Underwater acoustic (UWA) OFDM system is proposed. In the proposed scheme, every distinct phase sequence is represented by a unique Orthogonal comb pilot sequence (OPS), and the orthogonal properties of the OPSs are used to distinguish the index of phase sequences at the receiver. Therefore, the proposed scheme does not need to reserve bits for transmitting SI, so that the data rate can be raised. Simulation results show that the PAPR reduction performance has almost 0.5dB gains comparing to the Conventional SLM (C-SLM) scheme and the Bit error ratio (BER) performance is approximately the same as the SLM scheme with perfect SI. Field experimental results also demonstrate that the proposed scheme can differentiate phase sequences, therefore significantly enhance the quality of the UWA OFDM communication system.     

TD-SCDMA与WCDMA扰码规划比较

由于WCDMA和TD-SCDMA的扰码组成有着根本性的区别,本文对两个系统扰码规划考虑的主要因素进行了深入的研究。在对码资源分析的基础上,对比了WCDMA和TD-SCDMA规划特点的区别,得出了WCDMA和TD-SCDMA系统扰码规划应该遵循的不同原则。     

WiMAX技术经济分析及应用探讨

本文首先介绍了WiMAX的技术特点,然后着重对WiMAX技术的当前两大主流业务--中小企业数据和语音业务、家庭用户数据和语音业务进行了经济分析,提出在当前情况下,WiMAX可以考虑在有一定业务需求的地方进行部署,最后对WiMAX的应用进行了分析和探讨.