同异步交错教学法在工科数学教学中的实践

在工科数学教学中,改变传统的同步教学方法为同步教学和异步教学交错进行的教学方法,并以工科数学中的一个知识点"可导与连续"的教学进行实践,促进了学生学习能力培养,取得了较好的教学效果。     

一种改进的LTE系统下行同步算法

LTE（Long Term Evolution）系统中,作为小区搜索的第一步,符号定时算法需要具备很强的鲁棒性。为了进一步增强现有符号同步算法的抗频偏性能,提出了一种优化的符号同步算法。该算法一方面保持已有分段相关同步算法的优点,同时考虑结合预频偏处理来进行符号定时与粗频偏的联合估计,再将多个相关运算集做叠加处理。理论分析和仿真实验结果表明,在多径信道下,所提算法在完成符号定时和粗频偏估计的同时,大大提高了系统抗频偏性能。     

一种基于位同步的复杂调制样式识别方法

针对卫星数字化视频广播第二代标准（Digital Video Broadcasting-Satellite -Second Generation,DVB-S2）中的多进制幅度移相键控（Multiple Amplitude and Phase-Shift Keying,MAPSK）和多进制正交幅度调制（Multiple Quadrature Amplitude Modulation,MQAM）信号的调制识别,提出了基于位同步的识别方法。首先利用信号星座图特征对信号包络进行位同步,然后统计信号码元的幅度值个数及其幅度值分布提取统计特征参数,最后利用特征参数完成识别。仿真结果表明,所提算法在载波频率等参数未知的条件下,能够有效对信号进行调制识别。     

基于嵌入式平台的高速CCSDS帧处理设备设计

针对空间链路数据传输速率的提高,设计了一种基于嵌入式PowerPC和FPGA平台的高速、可配置的实时帧处理系统。主要描述了系统的硬件电路,采用了PowerPC作为主处理器进行控制与数据处理;采用FPGA作为外部输入输出接口,并进行CCSDS帧的解析处理。FPGA映射到PowerPC中EMIF一段地址空间,通过总线进行数据交互。FPGA设计采用VHDL语言描述,主要对帧同步机制、RS译码进行设计。PowerPC设计采用Vxworks系统,满足实时性要求。实践证明系统的高速性和高可靠性。     

中国快速消费品战略性渠道建设初探

营销渠道的建设受特定因素的影响,特别是产品自身的特点在很大程度上影响着营销渠道的选择。产品的特点决定了企业对目标市场的选择和消费者的购买习惯,因此产品的行业特点在很大程度上决定着企业营销渠道的建设。中国特殊的国情决定了在中国进行渠道建设必须要有中国的视角,要从战略的高度把握中国渠道建设。时刻关注中国的市场特点。     

The Discouraging Effect of Risks in WTO Negotiations: Determinants and Perceived Changes

The observation has frequently been made that uncertainty about the legal meaning and the economic and political effects of WTO agreements exert a discouraging effect on the progress of multilateral trade negotiations. This article identifies the determinants of uncertainty and risk in the WTO. It also examines changes in these determinants over time, pointing to increasing levels of uncertainty and risk. The argument is based on a series of interviews conducted with members of national delegations to the WTO and with WTO employees.     

Stock Returns,Productivity, and Corruption in Eight European Fast-Emerging Markets

This article addresses the impact of productivity, corruption, and trade openness on the stock returns of 265 industrial companies listed in eight Eastern European fast-emerging markets, over the 2004-2013 period. Through a three-factor model that includes both measures at firm level and macro-level control variables, our findings suggest that country corruption index is negatively correlated with the total annual return of the stocks of the listed industrial companies of our sample. Moreover, the most productive firms are featured by higher stock returns, while leverage seems not to be a key predictor of stock returns. In addition, the article uncovers innovative evidence about trade openness that is negatively correlated with stock returns due to its connection with the recent financial crisis. That is, firms operating in markets that are more open to trade show a higher degree of interconnection with other economies and are more likely to undergo the effects of negative fluctuations from foreign markets during the economic crisis. © 2015 Wiley Periodicals, Inc.     

基于FPGA 的1GHz高速采样处理平台设计

介绍了一种高速宽带采样的数字信号处理平台设计方法，论述了在XilinxV4 FPGA中如何实现高速同步时钟设计和高速数据同步接收设计，介绍了与该设计相关的一些高速模数混合电路设计方法和一种采样后数据捕获的方法。该设计方案已用于瞬时测频中，并取得了良好的效果。     

A $15 U.S. Minimum Wage: How the Fast-Food Industry Could Adjust Without Shedding Jobs

We consider the extent to which U.S. fast-food businesses could adjust to an increase in the federal minimum wage from its current level of $7.25 an hour to $15 an hour without having to resort to reducing their workforce. We consider this issue through a set of simple illustrative exercises, whereby the US raises the federal minimum wage in two steps over four years, first to $10.50 within one year, then to $15 after three more years. We conclude that the fast-food industry could absorb the increase in its overall wage bill without resorting to cuts in their employment levels at any point over this four-year adjustment period. We find that the fast-food industry could fully absorb these wage bill increases through a combination of turnover reductions, trend increases in sales growth, and modest annual price increases over the four-year period. Working from the relevant existing literature, our results are based on a set of reasonable assumptions on fast-food turnover rates, the price elasticity of demand within the fast-food industry, and the industry’s underlying trend for sales growth. We also show that fast-food firms would not need to lower their average profit rate during this adjustment period.     

大动态PCM/FM信号的载波频率同步

针对大动态脉冲编码-频率调制（PCM/FM）遥测信号的载波频率同步,提出了基于快速傅里叶变换（FFT）及频谱重心的载波频率估计方法,并采用了频谱叠加及频谱截取的优化方法提高算法估计精度。相对于其他基于FFT的频率估计算法,频谱重心法有着更高的估计精度及更好的抗噪声性能,而且复杂度代价很小。仿真的均方误差结果表明,基于FFT长度为2 048和2块叠加以及保留信号99.9%能量的频谱截取方案有最好的估计性能。在最大多普勒频率、多普勒一阶变化率及二阶变化率分别为0.5倍、0.3倍及0.2倍符号率的大动态条件下,基于频谱重心法的二阶锁频环能够较好地完成载波频率跟踪。误码率曲线表明,经过频偏校正后的多符号非相干解调（MSD)性能与无频偏情况相比,无性能损失。