基于递归神经网络的卷积码解码器的研究

详细介绍了一种基于递归神经网络(RNN)的1/n卷积码解码器的原理与实现。仿真结果表明RNN解码器与Vterbi解码器效果很接近,对一些特殊的卷积码,性能非常好。并通过模拟退火技术对此解码器的性能进行了改善。     

一种改进的差分空时协同分集方案及误码性能分析

提出了一种分布式差分空时分集方案，通过对差分编码方式的改进，可使用多种星座形状来进行调制。在采用了QAM星座调制时，比传统的PSK调制具有更好的性能，可以改善无线网络中的能量效率。在不考虑协同节点间误码的情况下，分析和推导了平坦衰落瑞利信道下该方案的SER性能上限的表达式。仿真结果表明采用QAM调制下的DSTBC性能优于PSK调制下的DSTBC。同时在慢衰落的条件下，仿真结果和理论分析的结果吻合较好，说明了方案的有效性。     

一种基于6进制概念的对转无刷直流电动机起动解算方法研究

提出了一种基于“6进制”概念的对转稀土永磁无刷直流电动机起动解算方法。文中利用内、外转子相对于电动机壳体的两组独立的位置代码,并根据位置代码的循环变化特性,引入“6进制”概念,得出了36种内、外转子相对位置状态代码的等价性,并依此给出了实用的起动解算方法。由于以“电角度”为基础进行讨论,所以得到的方法和结论适用于任意极对数的对转稀土永磁无刷直流电动机的起动问题。     

移动通信中发送分集性能分析

发送分集技术是第三代移动通信系统(3G)中的一种关键技术。主要分析了两种基于空时编码的发送分集:STTC和STTD。从成对错误概率角度和误码率等方面讨论了两种发送分集的性能。最后,进行了计算机仿真,并给出结论。     

复合测距伪随机码的选择

阐述了测距系统对测距伪随机码的一般要求,讨论了复合测距码的参数选择准则,介绍了复合测距码的构造原理,并提出了两种基于择多序列的改进复合测距码。     

SPC乘积码用于纠删译码的性能分析

SPC乘积码是一种既可以纠错,又可以恢复删除的高效码。该码的最小码距是4,能够恢复所有单阶,两阶和三阶的删除模式,实际上这种码能够恢复更高阶的删除模式。传统上是通过最小码间距来评价SPC乘积码译码性能,若从其空间结构入手,能够推导出SPC乘积码迭代译码后删除率的新上界。仿真显示这个上界更紧。     

Turbo-DFH Coding and Iterative Decoding

We combine the Turbo codes with differential frequency hopping （DFH） technique and propose a new technique called Turbo-DFH coding. The structures of Turbo-DFH encoder and decoder are given. Taking aim at characteristic of Turbo-DFH system, the modified Log-MAP algorithm is presented and used for iterative decoding of Turbo-DFH decoder. Simulation results show that because the ideas of random coding and iterative decoding are used, the bit error rate （BER） performance of the Turbo-DFH system is better than that of the conventional DFH system.     

Yesterday's Principles: Today's Challenges.

Discusses some of the questions faced by industrial psychologists in light of Title VII of the Civil Rights Act of 1964 and other fair employment codes. The author suggests that it is appropriate and timely for social scientists to reexamine and expand their role amidst the inevitable pressures of social legislation. For example, the psychologists' responsibility may, with justification, be extended to developing a climate of readiness on the part of clients for accepting social change. This can be done in part by developing an "idea exchange" to be published in our professional media incorporating the studies and experiences of psychologists in general relating to the problems arising out of the civil rights developments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recent trends in repair and refurbishing of steam turbine components

The repair and refurbishing of steam generator components is discussed from the perspective of repair welding philosophy including applicable codes and regulations. Some case histories of repair welding of steam generator components are discussed with special emphasis on details of repair welding of cracked steam turbine blades and shrouds in some of the commercial nuclear power plants using procedures developed.