FRFT-OFDM系统联合同步算法

研究OFDM系统中的同步问题. 通过对LFM信号在分数阶傅里叶域能量汇聚性的分析,提出一种基于FRFT的具有较低复杂度的联合载波频率、采样频率以及符号定时的同步算法.该算法在分数阶傅里叶域对由插入到OFDM符号中的LFM信号所产生的对称点进行搜索,结合FRFT的时移、相移以及分数阶卷积等性质,对3种偏差进行估计.仿真结果表明,该算法的性能随LFM信号长度的增加而提高,且优于其他同类算法.     

Interactions among Dietary Pattern,Physical Activity and Skinfold Thickness

Abstract

This study was designed to assess the effects of a specifically designed perceptual-motor training program on the level of perceptual-motor development, self-concept, and academic ability of kindergarten children. Subjects for the study were 40 kindergarten children randomly assigned to 1 of 2 groups. Each group received the same kindergarten program with one exception, the experimental group was exposed to a specifically designed perceptual-motor program 30 min daily for 5 mo, while the control group received a free play period for 30 min daily. Results of the study indicated that the data tended to support the specificity of training concept. The variables showing the greatest change were the perceptual-motor tests which measured changes on specific aspects of the training program. There appeared to be some immediate transfer to academic abilities but this was not pronounced enough to suggest that perceptual-motor training was of real benefit in developing academic abilities for normal kindergarten children. In addition the follow-up test indicated no long term effects on academic performance.     

网上互动教学设计的实践与思考

本文提出网上教学设计的关键在于加强互动的观点,并结合电大开放教育试点“货币银行学”课程的具体实践,从“一个中心、两个结合、三个原则”等方面进行了具体阐述。     

Evaluating College Teaching

Subtle forms of prejudice called microaggressions occur in college classrooms, but the effective methods of managing such prejudice are not clear. This study explored teachers’ (N = 222) and students’ (N = 166) perceptions of vignettes describing classroom microaggressions and the effectiveness of various teacher responses to the microaggressions. Teachers of courses focused on diversity perceived microaggressions more negatively and were more likely to respond to the microaggressions than teachers of nondiversity courses. Students believed that teacher responses to microaggressions were effective and ignoring microaggressions was ineffective. The results suggest that teachers should in some way respond to classroom microaggressions. They also suggest that diversity awareness may be a factor in the ability of teachers to recognize subtle prejudice in the classroom.     

Students' Views of Teaching

Abstract

Much To Do About Writing: Teaching and Assessing Writing By Edward M. White San Francisco: Jossey-Bass, 1985, 304 pages, $19.95. Reviewed by David Taylor

A Poignant, Colorful Portrait: Refugee Scholars in America: Their Impact and Their Experiences By Lewis A. Coser New Haven and London: Yale University Press, 1984, xviii + 351 pages, $25.00. Reviewed by R. W. Franklin     

全面提高办刊质量 促进农业发展—— 《宁夏农林科技》 创刊50周年实践

综述了《宁夏农林科技》的办刊实践,结合地方特色论述了《宁夏农林科技》在服务本地经济建设、促进成果转化方面所发挥的作用,指出期刊存在的问题,并对未来发展提出了建议。