一种新的扩展复数正交空时分组码

Recent research challenges in the wireless communication include the usage of diversity and efficient coding to improve data transmission quality and spectral efficiency. Space diversity uses multiple transmitting and/or receiving antennas to create independent fading channels without penalty in bandwidth efficiency. Space-time block coding is an encoding scheme for communication over Rayleigh fading channels using multiple transmitting antennas. Space-time block codes from complex orthogonal designs exist only for two transmitting antennas. This paper generalizes a new complex orthogonal space-time block code for four transmitting antennas, whose decoding complexity is very low. Simulations show that the generalized complex orthogonal space-time block code has low bit error rate, full rate and possibly large diversity.     

中国传统纹样在服饰创意设计中的应用及影响

中国传统纹样的审美特征与吉祥寓意常常作为服饰创意设计的借鉴要素,其设计运用既有传统纹样的形似借鉴,更有传统精神本质的神似变化和创意再造。中国传统纹样是现代服饰创意设计的精神源泉和不竭动力。     

The Relation of Body Motility in Young Infants to Some Physical Traits

Fourth grade children learned consonant-digit associates of their choice from two novel, distinctive lists during daily, five-minute study sessions. Points exchangeable for free time reinforced correct responses on corresponding tests under high (80%) and low (20%) reinforcement conditions. Equivalent novel high- and low-reinforcement lists were also studied each day as homework on which, unlike session materials, correct test responses were reinforced equally (100%). Results showed that children preferred to study and learned more on the highly reinforced lists during the experimental sessions. Children also displayed a generalized nonreinforced preference for learning the “highly reinforced” homework material.     

基于嵌套圆的可视化聚类方法研究

将嵌套圆融入可视化聚类方法之中,探讨和研究了基于嵌套圆的可视化聚类方法和主要算法,并选择情报学领域的数字资源进行实证分析。实证结果表明,该方法既能够在有限的可视化空间提供海量资源的整体描述和全局视图展示,又可以根据实际需要对重要聚类簇或核心节点进行深入挖掘和个性化展示,能够为海量信息资源的深度开发与利用提供技术支持。     

旗传递(v,k,3)-对称设计的自同构群与它们的抛物子群

文章研究了(v,k,3)-对称设计D的分类;证明了如果群G是D的几乎单型的自同构群,即存在非交换单群X使得X≤G≤Aut(D),那么X∩Ga不可能是X的抛物子群.     

德国政治教育课程设计分析

政治课在德国学校政治教育中发挥着主导作用,承载着重要的社会政治职能.政治课特殊的教学目标和任务对课程设计提出了很高的要求,课程设计对政治课教学能否取得良好效果至关重要.本文试对德国政治教育课程设计的一般阶段及其特点进行分析,希望能对我国政治课教学有所启示.     

Hidden structure: Using network methods to map system architecture

In this paper, we describe an operational methodology for characterizing the architecture of complex technical systems and demonstrate its application to a large sample of software releases. Our methodology is based upon directed network graphs, which allows us to identify all of the direct and indirect linkages between the components in a system. We use this approach to define three fundamental architectural patterns, which we label core–periphery, multi-core, and hierarchical. Applying our methodology to a sample of 1286 software releases from 17 applications, we find that the majority of releases possess a “core–periphery” structure. This architecture is characterized by a single dominant cyclic group of components (the “Core”) that is large relative to the system as a whole as well as to other cyclic groups in the system. We show that the size of the Core varies widely, even for systems that perform the same function. These differences appear to be associated with different models of development – open, distributed organizations develop systems with smaller Cores, while closed, co-located organizations develop systems with larger Cores. Our findings establish some “stylized facts” about the fine-grained structure of large, real-world technical systems, serving as a point of departure for future empirical work.     

Modern Regression Discontinuity Analysis

Abstract

This article provides a detailed discussion of the theory and practice of modern regression discontinuity (RD) analysis for estimating the effects of interventions or treatments. Part 1 briefly chronicles the history of RD analysis and summarizes its past applications. Part 2 explains how in theory an RD analysis can identify an average effect of treatment for a population and how different types of RD analyses—“sharp” versus “fuzzy”—can identify average treatment effects for different conceptual subpopulations. Part 3 of the article introduces graphical methods, parametric statistical methods, and nonparametric statistical methods for estimating treatment effects in practice from regression discontinuity data plus validation tests and robustness tests for assessing these estimates. Section 4 considers generalizing RD findings and presents several different views on and approaches to the issue. Part 5 notes some important issues to pursue in future research about or applications of RD analysis.     

试论期刊设计中色彩的市场效应

色彩是期刊设计中最为直观也最具想象力的因素 ,它以其自身的机能和内在规律 ,在现代期刊装帧设计中发挥着愈来愈重要的作用 ,尤其体现在市场效应上 ,色彩的意义是其他形式不可替代的 .以几种杂志的装帧设计为例 ,具体阐述了色彩在期刊设计中的市场效应