基于ARM9的航空相机测控系统设计与实现

性能测试是航空数码相机生产和装备过程中非常重要的一个环节,对其的使用评估有着不可替代的作用;以三星的ARM9处理器S3C2440A和Windows CE操作系统为核心,结合现代接口技术,介绍了某型航空数码相机地面检测系统总体设计思路和系统构成,重点分析了主体电路的硬件设计和Windows CE系统下相关软件的编写;通过BCD拨码器,串口电路,处理器和LED数码管组成模块模拟飞行状态输入和显示,编写相关软件完成了图像数据的格式转变和实时显示;实际使用结果显示,该检测系统运行稳定可靠,具有一定的实用性和参考价值。     

数据库系统原理课程中性能调优实验的设计与实践

论述了浙江大学计算机科学与技术学院采用数据库性能调优作为课程实验内容,分析讨论实验的过程、要求和内容安排等。性能调优是数据库系统应用开发的一项重要工作,具有实践性强、综合知识要求高等特点,非常适合于在探究型教学中作为实验内容。在本科生的数据库课程教学中进行了实践,取得了较好的效果。     

瞬间永恒——天津国庆彩车展演服装设计中的思考

人物展演服装设计,是天津国庆彩车整体设计系统中的重要组成部分。文章从主题设计、意象表现与造型特点等角度分析了天津国庆彩车中展演服装设计的特质与创意点,指出展演服装设计的关键在于准确定位,并以服装设计独特的艺术语言表述其它设计元素所不能表达的语意内涵。     

基于数据流程变换的Mashup性能优化方法

Mashup是一种流行的web2.0应用,由开发者将互联网上多个web数据源的数据进行聚合构建而成.大多数mashup工具支持通过可视化的数据流程设计来开发mashup,但是缺少编程经验的终端用户设计的数据流程可能执行效率很低,当处理较大规模数据时mashup的响应时间会大幅增加.本文研究如何通过数据处理操作的合并拆分、次序交换、并行化等技术实现mashup的数据流程优化,提高mashup的性能及可扩展性.本文提出一种新的mashup性能优化方法,对多样化的mashup组件标注其操作语义特征属性及代价模型,定义适用于mashup的流程变换规则,针对用户设计的rnashup数据流程生成所有与其语义等价的流程,并提出算法建立流程之间的代价偏序关系图从而快速选择执行代价最小的流程.文中实现了一个mashup工具,实验表明该方法可以有效提高终端用户设计的mashup的执行效率.     

基于MCF52223USB数据采集系统的实时性研究

详细分析了基于USB传输的数据采集系统的实时特性。针对实时工业控制环境,研究了采用32位微处理器MCF52223进行AD采集,并通过USB总线通信方式向PC机传送AD数据的多路数据采集系统的实时特性,并从软件滤波、数据传输等方面提出了提高系统实时性的有效方法,最后较为具体地给出了MCU方和PC方的编程方法。     

A representation method for performance specifications in UML domain

Performance related problems play a key role in the Software Development Process (SDP). In particular an early integration of performance specifications in the SDP has been recognized during last years as an effective approach to speed up the production of high quality and reliable software. In this context we defined and implemented a technique for automatically evaluating performance aspects of UML software architectures. To achieve this goal the starting UML model of the software architecture under exam has been mapped into a performance domain afterwards analyzed. The performance indices are inserted in the UML model exploiting the OMG Profile for Schedulability, Performance and Time Specification standard. However, to really automate the process, it was mandatory to specify the UML software representation by fixing semantic rules. The goal of this paper is the formalization of the model representation, characterizing the syntax and the semantics through which specifying performance requirements and behaviors into UML models in order to be compliant with the technique we implemented.     

What affects information systems development team performance? An exploratory study from the perspective of combined socio-technical theory and coordination theory

Quality is an important factor in information systems development (ISD), and ISD team performance closely relates to quality. To better understand ISD teams, we empirically tested a model on ISD team performance by combining socio-technical theory and coordination theory. Using existing empirical studies and data collected from three well-known ISD companies in China, our research results identified influential characteristics of ISD team performance, and revealed similarities and differences between China’s ISD team performance and those in other countries. By the results, we find that knowledge sharing and major do not affect team performance. The compensation satisfaction to job performance is not significant in China, either. Our research provides suggestions for building and supporting ISD teams that could lead to performance improvements.     

A longitudinal study of the effects of Internet use and videogame playing on academic performance and the roles of gender, race and income in these relationships

In this research we examined the effects of Internet use and videogame playing on children’s academic performance. Gender, race, and income were also considered. Participants were 482 youth, average age 12 years old. One-third were African American and two-thirds were Caucasian American. All measures were completed twice, first in Year 1 and then one year later, Year 2. Results indicated that greater Internet use was associated with better reading skills, but only for youth initially low in reading skills. Videogame playing was associated with better visual-spatial skill but also with lower GPAs. Gender, race and income influenced Internet use, videogame playing and academic performance but not the relationships between using these technologies and academic performance. Implications of the results for increasing the benefits of technology use are discussed.     

Gender-differences in Self-efficacy ICT related to various ICT-user profiles in Finland and Norway. How do self-efficacy,gender and ICT-user profiles relate to findings from PISA 2006

In this paper, we explored the relationship between self-efficacy, Information and Communication Technology (ICT) user profiles, and gender. Self-efficacy is an important theoretical and empirical concept to identify and describe how students perceive their own ability to solve a task. ICT user profiles were developed as an empirical framework to identify and categorize students based on how frequent they use ICT. In this paper, we have chosen six ICT user profiles in order to distinguish between leisure activities and school activities. Each ICT user-profile was computed by combining two dimensions (frequency of ICT use for leisure purposes and frequency of ICT use for school purposes). We tried to identify how students’ perception of their ability to solve a task is related to both their gender and how frequently they use ICT. The results showed that student’s self-efficacy varied between the ICT user profiles. The findings showed how an increased level of self-efficacy in ICT High-level tasks is related to both an increased level of leisure use and with an increased level of educational use. Further, our findings provided evidence in support of positive relationships (for both males and the females) between Self-efficacy in ICT and the ICT user profiles.     

How does Internet information seeking help academic performance? – The moderating and mediating roles of academic self-efficacy

Although researchers tend to agree that Internet is a good source for learning and research, little empirical data has substantiated this claim by specifically linking time and effort spent on the Internet for school related information seeking to academic performances. This research investigates the relationship between vocational high school students’ information seeking activities on the Internet, academic self-efficacy, and academic performance. We propose that academic self-efficacy both mediates and moderates the relationship between Internet information seeking and academic performance. Using survey data from 295 vocational high school students in Taiwan, we found that the positive effect of Internet information seeking to students’ academic performance is mediated through academic self-efficacy. Academic self-efficacy, at the same time, moderates the relationship between Internet information seeking to academic performance such that students’ with low academic self-efficacy benefit more from Internet information seeking in regard to their academic performance. We discussed the implications of our findings and provided future directions for research.