基于三点工况下的无源滤波器组优化设计

无源滤波器组的参数设计通常均针对系统单一工况(通常为最大工况)进行。当系统运行在其他工况时,有可能无论退出哪一组滤波器的运行均无法同时满足系统的无功补偿和谐波治理要求。为此基于系统的3种典型工况(最大、平均和最小工况)对无源滤波器组进行优化设计,确定合理参数,以在最小的投资费用下达到谐波治理与无功补偿的最优匹配。算例结果验证了该方法的可行性。     

Efficient visual communication channels

This paper compares the efficiency of uniform quantization in the spatial domain with frequency dependent quantization in the spatial frequency domain, in the context of the end-to-end performance of visual-communication channels. Results show that the minimum data density required for informationally lossless transmission depends on the design of the image-gathering device. The information in the acquired signal, not the energy, dictates the trade-off between data transmission and visual quality. Frequency dependent quantization that maintains the information capacity of the channel while reducing the entropy of the encoded signal, improves its information efficiency. Information bit-allocation is preferable for optimized visual communication for restoration, whereas energy bit-allocation can be used only for image reconstruction.This research was supported by NASA Task Assignment NAS1-18584-90 with the Department of Mathematics, Old Dominion University, Norfolk, Virginia 23529.     

数字音频功放处理芯片设计与实现

介绍了一种数字音频功率放大器数字信号处理的基本原理与实现方法.对整个数字音频功放的数字信号处理器的设计进行了详细介绍,并通过Xilinx FPGA工具进行了验证,利用Synopsys工具进行了完整的电路设计、仿真和版图设计.流片采用Chartered 0.35μm工艺.     

基于LTC6804的锂离子电池阻抗测量系统设计

在对锂离子电池内部温度、寿命等状态估计中,常需要获得1~100 Hz下电池的阻抗信息。采用现有电池管理系统使用的LTC6804模块,基于数字锁相放大器原理设计了一套串联电池组阻抗在线测量系统,针对LTC6804设计电流采样电路,并对相关运算算法进行了适当改进,简化了硬件电路的设计及阻抗计算的过程,保证了阻抗测量的精度,阻抗模和阻抗角测量的误差均在5%以内,能够较好地适用于在线阻抗测量与电池温度估计等实际应用中。     

Optimality and convergence of adaptive optimal control by reinforcement synthesis

Adaptive Optimal Control (AOC) by reinforcement synthesis is proposed to facilitate the application of optimal control theory in feedback controls. Reinforcement synthesis uses the critic–actor architecture of reinforcement learning to carry out sequential optimization. Optimality conditions for AOC are formulated using the discrete minimum principle. A proof of the convergence conditions for the reinforcement synthesis algorithm is presented. As the final time extends to infinity, the reinforcement synthesis algorithm is equivalent to the Dual Heuristic dynamic Programming (DHP) algorithm, a version of approximate dynamic programming. Thus, formulating DHP with the AOC approach has rigorous proofs of optimality and convergence. The efficacy of AOC by reinforcement synthesis is demonstrated by solving a linear quadratic regulator problem.     

城中村问题调查与分析

以华北地区为主要研究对象,对秦皇岛山东堡地区进行了深入调研,从中发现城中村存在的一些共性问题,通过分析找出了症结所在并提出合理的解决方案。     

交流采样技术在嵌入式状态监测系统中的应用

为实现嵌入式状态监测系统对电站输出交流信号的实时监测,结合工程实际选用交流采样技术对信号进行采样,并利用适合的数字测量算法计算信号的真有效值和频率.通过仿真测试比较,快速傅里叶变换算法能在频率稳定和频率波动的情况下以较高的精度对异步采样信号进行技术参量求取,同时有效抑制了低次谐波和直流信号的干扰.将交流采样技术应用于嵌入式状态监测系统,不但利用嵌入式处理器的快速性和实时性克服了交流采样运算复杂的缺点,而且交流采样技术反向节省了系统的硬件开销,实现了优势互补.     

高速补充信道对cdma2000-1x前向链路功率分配的影响

分析了cdma2000-1x系统的前向信道发射功率分配。通过仿真试验及理论推导，给出了导频信道和业务信道信号质量之间的相互依赖关系并绘出导频信号和业务信道之间的相关性曲线：根据这种相关性曲线，从而发现使总发射功率最小的最佳导频功率；最后提出并分析了高速补充信道对cdma2000-1x前向链路功率分配的影响。     

Stochastic LQ-optimal control for 2-D systems

Stochastic LQ-optimal control problem is solved for linear 2-D systems via 2-D polynomial techniques. All stabilizing controllers are parameterized and then minimizing one is obtained. Its transfer function results from two 2-D spectral factorizations and a couple of linear equations in formal power series. A practically useful sub-optimal controller is also considered that results from truncated spectral factorizations and a couple of 2-D polynomial equations.     

新型耐温耐压多层结构管道及其壁温计算

为降低高温高压流体管道的制造成本,遵循耐温与耐压分离的原则,提出了一种耐温耐压的多层管道结构,并建立了计算该管道壁温的热力学模型,探讨了不同内管道外径时遮热管壁温、遮热管外半径和热流功率与遮热管数量的关系.结果表明:在内管道壁温为700℃时,随着遮热管数量的增加,外管道壁温迅速下降,最终可降至350℃以下,完全可以使用普通的钢材来制造耐压管道,大大降低了管道的制造成本.