从时空观看标志设计的新思路

本文先简要分析了现今流行的标志设计手法,从时间性和空间性出发,重新认识了二维标志的设计方法,探讨目前标志设计的一些动态发展方向,着重思考其在实际应用中所产生的一些标志设计的新思路。     

软件工程四位一体校企合作实践教学体系研究(英文)

To meet for the enterprise requirements of software engineers and to solve the problems that the software engineers with low capacity in engineering and innovation issues at present,this paper first analyzes the software engineering education objectives and methods,then proposes to build an engineering teaching architecture which called One Frame with Four Aspects.This architecture reforms the practical teaching experience from educational concepts,practical training links,practical training objectives as well as practical training evaluation mechanism,especially focuses on the content of practice teaching,engineering teaching curriculum,the school-enterprise cooperation model and evaluation mechanisms.Practice has shown that the practical teaching system can be applied to software training well in Software School and its training effect is remarkable.     

分组移动对象的区域偏离监视算法

以大量可分组移动对象的区域偏离监视问题为研究背景,扩展了基于区域覆盖的空间索引结构——虚拟网格四分树,提出了一种新的索引结构VGQ_G。基于VGQ_G,实现了区域偏离监视算法RDMA;给出了监视算法的性能对比实验。实验结果表明,在移动对象数量足够大的时候,设计的监视算法比朴素的监视算法在响应时间上提高了一个数量级。     

空间数据库中一种自适应的缓存替换策略

随着近年来空间数据库研究和应用的不断深入,针对空间数据库中数据组织和查询的特征来设计缓存页面替换策略成为一个新的研究问题.Voronoi图是一种重要的空间数据库组织技术,在处理kNN查询时具有非常好的性能.针对Voronoi图组织的空间数据库,首先利用空间局部性提出了一种基于欧氏距离的替换策略,在发生页面失效时选择距离上一次访问页面欧氏距离最远的页面进行替换;进一步,针对不同kNN查询的搜索空间大小差异非常大的特点,在LIRS替换策略基础上提出一种自适应替换策略,通过对HIR页面占缓存比例自动调整来适应不同的查询.综合两者,形成基于欧氏距离的自适应缓存页面替换算法AELIRS.大量实验表明,在缓存大小与搜索空间大范围变动中,AELIRS始终优于其他替换策略.     

基于聚类方法的空间度量物化选择算法

在空间数据仓库中,由于物化视图中空间度量的聚集结果需要占用较大的存储空间,因此只能选择部分空间度量进行物化.而现有的物化视图选择算法大部分只是针对视图选择设计的,没有考虑视图中度量的选择.为此,针对空间度量的区域合并操作,提出基于聚类方法的空间度量物化选择算法.把可合并的空间对象组进行聚类,在每个聚类中计算合并组的收益...     

基于信息熵的空间对象群聚类算法

针对利用空间关系建立空间对象群聚类的问题,提出一种基于信息熵的空间对象群聚类算法ESOGC。该算法考虑空间数据的复杂性和数据之间的联系,根据邻域范围内信息熵的变化情况,捡起或放下当前空间对象群,从而实现对空间对象群的聚类。实验结果表明,该算法能解决空间对象群中对象类型、对象属性值和对象数量不一致性的问题。     

Video game experience predicts virtual, but not real navigation performance

In recent years, studies have shown that video game experience is related to improvements across a variety of cognitive and visuospatial tasks. This study investigated the relationship between prior video game experience and spatial performance in virtual and real environments. Across two experiments, gaming experience was related to performance in desktop virtual environments; those with more video game experience were more accurate in pointing to nonvisible targets. In contrast, gaming experience was unrelated to three different real environment tasks, suggesting that video games may primarily influence perceptual and cognitive abilities in the visual domain over abilities that also involve kinesthetic or vestibular input. Contrary to expectations, gaming experience was also related to performance in immersive virtual environments, which may be related to the use of a joystick interface during immersive travel. Video game experience was also positively related to performance in a dynamic spatial task and to verbal SAT and math SAT scores. Sex differences in desktop virtual navigation and dynamic spatial ability were eliminated when game experience was included as a covariate.     

一种数据块关系指导的缓存替换方法

提出了一种数据块关系指导的缓存替换方法BDP(block correlations directed replacement policy).数据块关系所表示的空间局部性可以用来指导存储系统的缓存替换策略.BDP利用历史访问信息和实时访问信息,预测数据块未来的空间局部性特征,并设计数据块驻留时间的控制策略,减少现有替换算法对空间局部性预测失败带来的失效惩罚.同时给出了BDP的有效缓存模型.模拟结果显示,对大多数实际系统工作负载,BDP的失效率相对LRU算法下降11%～38%,优于现有的考虑空间局部性的替换算法.     

EST3火灾报警系统的应用层通信协议剖析

给出通信协议剖析的一般方法和步骤,介绍GE爱德华EST3火灾报警系统的组成。对该系统串行通信协议的结构以及数据链路层和应用层的帧格式进行剖析。举例说明其应用层的基本分组格式,包括命令服务帧格式、报告服务帧格式和日期／时间通告服务帧格式。     

面向用户的IMS媒体层统一安全框架

针对IMS媒体层安全保护机制存在的问题,提出一个面向用户的IMS媒体层统-安全框架,在此基础上设计了具体的实现方案,该方案能为用户提供灵活的媒体层安全保护机制,实现媒体层加密算法与密钥的安全协商,保证用户之间端到端的通信安全。实验结果证明了该方案的有效性。