Who contributes voluntarily to OSS? An investigation among German IT employees

Based on newly assembled survey data, we analyze which individual characteristics of IT employees are associated with the willingness to participate voluntarily in Open Source Software (OSS) projects. We find that, contrary to common expectations, formal educational attainment is not positively associated with the probability or level of OSS contributions. The group of university dropouts, however, does show a particularly high probability of working on such projects. Furthermore, we obtain the striking and novel finding that work-related OSS activities play an important role in determining voluntary OSS contributions during leisure time. Although one has to be cautious regarding the direction of causality, we interpret this as evidence of career-oriented motives in voluntary OSS contributors. The finding is also reinforced by our more specific analysis of the importance of such motives in determining the actual effort invested in OSS projects.     

H.264熵编码的技术研究及H.264的应用展望

随着视频通信的发展,多媒体通信平台功能越来越强大,同时也对视频编码的性能提出了更高要求。H.264视频编码标准正因为使用了熵编码技术,使得其压缩效率大大提高,同时图像质量和差错鲁棒性方面也表现优异,成为图像处理和通信领域研究的热点问题之一。论文搭建了H.264的系统框图,对H.264的三种熵编码分别进行了技术研究,得到H.264编码的整体优势,通过其在视频通信上的应用调查,阐述H.264的前景。     

高校甲型H1N1流感监测系统的设计

针对高校的实际需求,研究基于B/S模式的甲型H1N1流感监测系统.文章介绍了该系统的内容,分析了系统的特色,同时,阐述了该系统的推广前景.     

视讯业务新热点--视频会议系统

视频会议系统集语音、数据、图像为一体，可帮助相隔千里之外的人们实现面对面的实时沟通，它分为软件视频会议系统和硬件视频会议系统。硬件视频会议系统价格昂贵，但稳定性强，视频质量可靠；软件视频会议系统价格低廉，实现方便，易于升级维护，是视频会议系统今后的发展方向。     

尖晶石型复合氧化物MAl_2O_4（M=Sr,Ba）的制备、表征及可见光催化性能研究

用柠檬酸络合法制备了尖晶石型复合氧化物SrAl2O4、BaAl2O4,用XRD、TEM等手段对催化剂结构和性能进行了表征,并考察了其在可见光下降解刚果红的催化性能。结果表明,在可见光条件下,60 min内BaAl2O4使刚果红降解率达80%以上,SrAl2O4降解率大约为70%。SrAl2O4的催化活性低于BaAl2O4可能是由于电子层结构的不同造成的。     

Effects of school choice on the margin: The cream is already skimmed

Critics of school choice argue that cream-skimming will worsen outcomes for those left behind in public schools. Since “high ability” families may have already sorted themselves out of the schools in question, this paper will examine whether existing within-school heterogeneity leaves any scope for cream-skimming to operate. It asks, “given the current level of within-school heterogeneity, how strong would peer effects have to be to significantly worsen outcomes for those left behind?” In order for cream-skimming to lower math test scores by one half-year's progress, the peer effect would have to be as strong as increasing class sizes by 8–20 students, or cutting per-student funding by $400–2000. These results indicate that current levels of within-school heterogeneity are so low that peer effects would have to be unrealistically strong to give cream-skimming any bite.     

氢原子光谱同位素谱线位移实验的参数优化

讨论了氢原子光谱实验中狭缝宽度、采集次数和负高压对氢原子光谱同位素位移谱线的影响,优化了氢原子光谱同位素位移实验的工作参数,获得了清晰的氢原子同位素位移光谱。通过该实验让学生掌握实验中多参数优化的方法,有利于加深学生对光谱理论的理解,有利于提高学生分析问题解决问题的能力。     

谢拉的文献工作教育思想与实践

在1952—1970年担任西储大学图书馆学院院长期间,谢拉积极探索文献工作教育:在学科理论方面,进行文献工作学科理论建设;在学术研究方面,设立美国图书馆学院第一个专门的文献工作研究中心“文献工作与交流研究中心”;在教学活动方面,在图书馆学教育项目中引入文献工作相关课程,强化以文献工作为重点的专业图书馆人才培养。谢拉的文献工作教育是对传统图书馆学教育的改造,适应了图书馆学教育专门化的发展趋势,其立足点是以文献工作提升图书馆职业的社会价值,服务于图书馆人才培养,体现出明显的图书馆本位立场。谢拉领导下的西储大学图书馆学院的文献工作教育是一种过渡形态的早期情报学教育,促进了20世纪美国图书馆学教育向图书情报学教育格局的转型。参考文献62。     

NSP:一种作者评价指标及其与H指数之比较

介绍由M.Kosmulski提出的成功论文概念以及一种以计算成功论文篇数为基础的作者评价方法--NSP方法,并总结该方法与H指数方法的异同。以我国图书情报学领域100名作者为例,分别计算出每人近10年间的NSP与H指数,并对结果加以分析,讨论变化原因,当多人分数相同时,可通过对作者合著情况加以控制来提高区分度,最后分析NSP与H指数各自的适用范围及NSP的潜在局限性。     

采用六西格玛工具降低矩形坯白点缺陷率

利用六西格玛工具,通过对本钢矩形坯白点的成因分析,提出了采用控制入炉物料的干燥、对白点敏感性钢种采取RH真空处理、加强坯材保温等措施,可有效控制白点的产生。得出如果钢水〔H〕含量控制在5ppm以下可以基本保障钢材不出现白点缺陷。