System prototype for vehicle collision avoidance using wireless sensors embedded at intersections

This paper presents research results regarding a vehicle collision avoidance system that uses a wireless sensor platform and communication based on 802.15.4 standard. The system is comprised of two components: monitoring stationary nodes mounted on the road and mobile nodes installed in vehicles. Signal strength and link quality indicators are evaluated to assist in the sequence identification of vehicles as they approach each other at an intersection. The study shows the feasibility of implementing 802.15.4 standard in wireless sensor network communication to act as a time-critical vehicle warning system that can be used for safety application.     

Components, systems and discontinuities: The case of magnetic recording and playback equipment

Using the history of magnetic recording and playback equipment, this paper explores the relationship between incremental improvements in components and technological discontinuities in systems. It finds that improvements in components have been the major source of all discontinuities in the industry. Focusing just on tape-based systems, all of the basic design approaches had been identified by the late 1950s and thus one of the largest technological challenges for firms has been to modify the design in response to improvements in the magnetic recording density of tape. This paper explores this phenomenon by analyzing data on equipment performance and price, and several design choices for the tape-based equipment. It shows how improvements in the magnetic recording density have changed the tradeoffs that exist between price and different dimensions of performance and between various design choices and thus led to about 10 technological discontinuities in magnetic tape system design.     

航空分销系统在电子商务中的应用

从传统航空分销系出发,提出了改进的系统模型,确立设计分销系统的目标,并分别从系统的业务构架,商业运作,技术方案详细分析了本文设计的系统在电子商务运作中的优势和作用。     

运用VFP9.0实现环境监测信息系统

数据库技术的成熟发展,为环境管理信息化提供了强有力的工具。建立一个科学合理、维护使用方便的基层环境监测信息系统也就成了可能。通过介绍Microsoft公司数据库Visual Foxpm9.0的特点,结合县级环境监测部门的工作实际,探讨了基层环境监测信息系统的开发。     

一种入侵容忍的资料库

ARECA的设计保护了CA私钥的保密性，使ARECA能实时在线地为用户签发证书或撤销证书；但作为安全的在线CA，分发证书的资料库的安全也是关键问题。ARECA的资料库是入侵容忍的，通过将复制的服务器组织成分发屏蔽失效法定数目团体系统，能屏蔽良性失效或者被攻击者控制的服务器的行为，为用户提供正确的证书和证书撤销列表查询服务。异步通信条件下，n>3f个服务器组成的资料库能够容忍至多f个服务器同时失效。     

资源系统工程的研究与应用

本文从资源定义出发,提出资源系统是指在一定区域内能够产生经济价值的、以提高人类当前和将来福利因素和条件的复杂系统。资源系统工程是对资源系统进行合理规划、设计和运行管理的一门交叉学科。研究分析认为：资源系统工程的理论基础是系统工程理论、系统工程技术和资源科学,研究的主要内容为资源系统规律、资源开发利用、资源协调控制,并初步确定了资源系统工程研究的方法论和学科体系。文章最后指出资源生态学、资源信息学的研究、资源系统定量分析,以及现代工程技术和方法的采用是资源系统工程研究的重点方向。资源系统工程是一门正在孕育发展中的学科,有待进一步去探索。     

"一国两制"提出的历史条件及其实践过程初探

“一个国家 ,两种制度”是解决祖国统一问题的重大战略构想 ,是邓小平理论的主要组成部分。对资本主义的重新认识是“一国两制”提出的基本前提 ;台港澳现状是“一国两制”战略决策的客观条件 ;争取在国际关系和两岸互动中占据主动是“一国两制”决策提出的战略目的 ;“一国”条件下“两制”关系如何处理是“一国两制”决策必须面对的最大现实。     

Training preservice teachers to use evidence-based practices: Effects of coaching with performance feedback on teacher and child outcomes

Three-term contingency trials (TCTs) involve planned/naturally occurring antecedents, child's demonstration of target behaviors, and planned/naturally occurring consequences. Positive relationships between teachers' frequent use of TCTs and children's learning were noted in literature. This study aimed to investigate impact of an intervention package including training and coaching with performance feedback on experienced and novice special education preservice teachers' use of TCTs and relationship between teachers' implementation and child outcomes through two single-case experiments using multiple baseline across participants design. Three special education preservice teachers and three children with disabilities participated in each study. Results indicated intervention package was effective in increasing preservice teachers' use of TCTs. Preservice teachers generalized their use and sustained it during maintenance sessions conducted after intervention ended. Furthermore, as frequency and accuracy of preservice teachers' implementation increased, percentage of children's correct responses in relation to target skills improved. Implications for future practice and research are discussed.     

数字图书馆-理想与现实

文章首先讨论理想的数字图书馆概念,介绍并比较两个主要的数字图书馆项目类型:研究型和实践型。在此基础上,论述了“混合图书馆”的概念及其特征、目标和任务,讨论混合图书馆较之理想中的数字图书馆,在资源、服务和系统等方面所面对的更为复杂的情况和问题,并从整合机制以及图书馆系统的选择等方面,提出混合图书馆目前需要关注的几项工作。     

基于Windows的父子线程控制实验设计

目前基于Linux系统的“操作系统原理”课程父子进程控制实验,都是通过调用Linux系统的函数fork0创建子进程的方法来实现。为了使高职高专学生在学习课程的同时提高在Windows系统下的编程能力,设计了基于Windows的父子线程控制实验。