A data collection protocol for real-time sensor applications

The nature of many sensor applications as well as continuously changing sensor data often imposes real-time requirements on wireless sensor network protocols. Due to numerous design constraints, such as limited bandwidth, memory and energy of sensor platforms, and packet collisions that can potentially lead to an unbounded number of retransmissions, timeliness techniques designed for real-time systems and real-time databases cannot be applied directly to wireless sensor networks. Our objective is to design a protocol for sensor applications that require periodic collection of raw data reports from the entire network in a timely manner. We formulate the problem as a graph coloring problem. We then present TIGRA (Timely Sensor Data Collection using Distributed Graph Coloring) — a distributed heuristic for graph coloring that takes into account application semantics and special characteristics of sensor networks. TIGRA ensures that no interference occurs and spatial channel reuse is maximized by assigning a specific time slot for each node. Although the end-to-end delay incurred by sensor data collection largely depends on a specific topology, platform, and application, TIGRA provides a transmission schedule that guarantees a deterministic delay on sensor data collection.     

图像边缘检测在DM642上的应用研究

采用TMS320DM642EVM作为数字图像处理硬件平台,利用CCS开发环境来构建程序并对其进行优化;通过对改进后的Log算子和小波多尺度方法提取到的边缘图像进行数据融合,得到一幅新的边缘图像。实验结果表明,该方法提高了边缘检测的运算速度,满足了实时性要求;并能有效地抑制噪声的影响,保留了图像边缘细节。     

Logistic混沌网络会议加密系统的设计

文章采用Logistic混沌序列对实时视频传输系统进行数据的分块加／解密,并从算法的安全性、效率等方面进行了性能分析,该算法具有良好的实时性、快速性和易实施性,可以有效地防止敏感信息被轻易的窃取、篡改和传播,有效保障网络视频传输的流畅性及安全性。     

基于CC1100的无线抄表系统

介绍了一种利用单片机和CC1100无线通讯芯片构成的无线抄表系统,叙述了工作原理和实现过程,并重点介绍了CC1100的电磁波唤醒功能和原理,给出了详细的结论.     

一个基于Web日志的用户访问数据分析系统

通过结合网站设计初期的网站结构和典型用例的预先定义,构建一个基于Web日志数据的用户访问数据分析系统。该系统（AS-UAB,Analysis System of User Access Behaviors）通过对网站结构和典型用例的预先植入,利用该领域最新的研究方法和结论,为网站相关人员提供可视化的用户访问信息统计及趋势预测,网站结构设计及交互设计上存在的问题及改进建议等通用功能和个性化定制功能。     

遗传编程在符号回归中的应用

遗传编程是一种新型的搜索优化技术,文章介绍了遗传编程的基本原理,以及遗传编程的算法设计及其实现的几个关键问题,并研究了基于遗传编程方法的符号回归。与传统回归方法相比,该方法得到的拟合函数更精确,具有更广泛的适用性。文中通过对一个函数进行符号回归验证,说明此方法合理可行。     

The effect of time of day on injury patterns amongst adolescents in Australia

Labour force participation of adolescents in Australia is growing at an unprecedented rate. This increased participation is coupled with a growing realisation of the vulnerability of adolescents in the labour market in terms of occupational injury. Despite recent evidence that time of day may be an important determinant of adolescent injuries, the impact of non-standard and night work on adolescent injury rates has received scant attention to date. The current study addresses this shortcoming by examining injury patterns of 3201 working adolescents in Queensland. Results revealed that female adolescents are 2.5 times more likely to sustain an injury on day shift and 4.71 times more likely to sustain an injury on night shift than their adult counterparts when total work hours are taken into consideration. Similar results were found for male adolescents with an injury to work hours ratio of 2.19 on day shift and 3.05 on night shift. These findings point to the value of considering the temporal pattern of adolescent work in future research aimed at minimising injuries at work and improving the work experience of tomorrow's workforce.     

XML发布/订阅数据流系统基于共享的多查询连接算法

XML的发布/订阅系统中的XML多查询连接,涉及到多个XML文件之间关系的订阅的处理,包括了对XPath路径模式的评测,对XML文档之间的比较计算以及对系统时间进行管理等方面。基于共享的连接算法,通过适当的组织,使得多个订阅之间相同的变量连接计算结果得以被重复利用,较大程度地减少了开销很大的连接计算,从而较大地提高系统效率。实验结果表明,基于共享的算法取得了良好的实际效果,能适合于百万以上订阅的场合。     

Entrepreneurial acquisitions,open innovation and UK high growth SMEs

This paper examines the dynamics of entrepreneurial acquisitions undertaken by UK high growth small and medium enterprises (SMEs). While entrepreneurial acquisitions are increasingly deployed by SMEs, little is known about their antecedents, motivational drivers and organisational outcomes. Drawing on detailed case study evidence from Scotland, the key factor found to be driving these acquisitions was the desire to augment and exploit technological complementarities between the acquiring and acquired firms. Acquisition can therefore be conceptualised as an advanced stage of the outside-in ‘open innovation’ strategies proactively used within these innovative SMEs. Firms executing this strategy typically have an acute propensity for risk, a desire for close customer engagement, effective business models and strong external orientation. The work suggests that greater attention should be paid within M&A theory to the dynamics of these types of smaller scale entrepreneurial acquisitions.