宽带码分多址系统无线资源管理的最优实现

本文通过定性分析宽带码分多址（WCDMA）系统的业务吞吐量的最大化,推导出了WCDMA系统无线资源管理的两种最优化方案,第一种是用户以相同的速率传输数据,在每信道发射功率受限条件下分配最小的功率给用户;第二种是在总发射功率受限制条件下分配给用户不同的传输速率。文章最后通过实际系统的分析比较了这两种方案的实现效果。     

An inter-lighting interference cancellation scheme for MISO-VLC systems

In this paper, we propose an inter-lighting interference cancellation (ILIC) scheme to reduce the interference between adjacent light-emitting diodes (LEDs) and enhance the transmission capacity of multiple-input–single-output (MISO)-visible light communication (VLC) systems. In indoor environments, multiple LEDs have normally been used as lighting sources, allowing the design of MISO-VLC systems. To enhance the transmission capacity, different data should be simultaneously transmitted from each LED; however, that can lead to interference between adjacent LEDs. In that case, relatively low-received power signals are subjected to large interference because wireless optical systems generally use intensity modulation and direct detection. Thus, only the signal with the highest received power can be detected, while the other received signals cannot be detected. To solve this problem, we propose the ILIC scheme for MISO-VLC systems. The proposed scheme preferentially detects the highest received power signal, and this signal is referred as interference signal by an interference component generator. Then, relatively low-received power signal can be detected by cancelling the interference signal from the total received signals. Therefore, the performance of the proposed scheme can improve the total average bit error rate and throughput of a MISO-VLC system.     

微带长度及阻抗比对SIR带通滤波器的谐波频率的影响

分析了微带长度及阻抗比对SIR带通滤波器的谐波参数的影响，并利用Angilent ADS仿真软件分别对不同长度及不同阻抗比的滤波器电路进行仿真分析，找出谐波频率随微带长度及阻抗比变化的规律。     

一种小型的交叉耦合阶梯阻抗谐振器带通滤波器

利用小型化的阶梯阻抗谐振器设计了一种交叉耦合带通滤波器.引入的交叉耦合结构在带外产生了一对传输零点以更好地抑制带外干扰信号而不影响通带特性.由于采用了小型化的阶梯阻抗谐振器,交叉耦合带通滤波器尺寸大为减小,同时寄生通带移向更高端.实验和仿真结果基本一致.     

Strategic measures in optimal control problems for stochastic sequences

Controlled discrete–time stochastic processes axe studied using the convex–analytic approach. Some new properties of strategic measures spaces are established, particular Markov models are considered. The meaningful example is presented.     

SARS传播的数学模型的建立与分析

建立一个SARS传播的实用的、可求解的改进SIR模型,并用差分方法进行求解。利用北京SARS病例数据对模型验证表明,拟合曲线与实际数据基本吻合,平均相对绝对值误差为0．0153。对隔离时机的提前或延后造成的后果进行数值分析,可得出最终确诊病例累计数与隔离时机的延长或提前呈指数增长或下降的结论。     

Effects of superspreaders in spread of epidemic

Within the standard SIR model with spatial structure, we propose two models for the superspreader. In one model, superspreaders have intrinsically strong infectiousness. In other model, they have many social connections. By Monte Carlo simulation, we obtain the percolation probability, the propagation speed, the epidemic curve, the distribution of secondary infected and the propagation path as functions of population and the density of superspreaders. By comparing the results with the data of SARS in Singapore 2003, we conclude that the latter model can explain the observation.     

一种设计小型滤波器的方法

体积更小、性能更高、成本更低且更易于大量生产是现在滤波器发展的趋势。体积的减小,使得滤波器的内部耦合的情况更加复杂和难以设计。提出一种设计小型滤波器的新方法,并设计了一个小型的微带环行阶跃阻抗(SIR)带通滤波器。这种方法就是先根据经验公式估算出了环行SIR单元的尺寸和抽头线位置;对Ansoft HFSS软件进行二次开发,利用遗传算法控制多台计算机上的Ansoft HFSS软件并行优化SIR单元的尺寸和抽头线位置。优化后的滤波器,满足设计指标,加工后进行实测,实测结果与仿真结果几乎完全一致。实验结果表明所提出的方法能准确、高效地设计一种设计小型滤波器。