基于组件的虚拟实验室反馈模型

提出了一种基于组件的虚拟实验室反馈模型. 该模型针对虚拟实验室中的实验设备以组件形式实现的特点, 把实验流程的拓扑结构以及实验设备的参数转换为有特定含义的字符串, 同时建立一个实验参照库, 库中预存好标准实验流程字符串, 用户实际搭建的实验流程字符串与库中的预存字符串进行模式匹配, 从而根据匹配结果给出实验指导意见. 该模型满足了学习者在虚拟实验过程对于纠错指导和效果评价的需求, 为改善学习者的使用体验提供了一种解决思路.     

虚拟环境下网络安全实验系统的构建

以QEMU为实验操作系统,通过Dynamips加载和模拟网络设备,采用MVC软件技术架构,从系统框架、实验界面、虚拟机资源管理、网络设备管理、实验结果保存等方面进行了虚拟环境网络安全实验系统的设计。     

一种虚拟路由器资源映射算法研究

网络虚拟化技术的提出,为解决互联网"僵化"问题找到了新的思路,受到广泛的关注。在虚拟路由器平台中,若干台互联的网络服务器资源组成了底层物理网络,通过虚拟网络映射技术,将物理网络资源有效地映射到虚拟网络设备上,组成多个虚拟网络,满足用户对网络的多样化需求。虚拟路由器资源映射问题是虚拟网络映射问题的基础,虚拟路由器实例与物理资源的映射方法决定了虚拟网络平台资源的利用率和虚拟网络系统的性能。针对虚拟路由器平台资源分配的问题,提出了物理网络资源模型和虚拟路由器资源请求模型,设计了一种启发式虚拟路由资源分配算法,并对算法的复杂性和优化目标进行了分析。     

Chasing the White “WHALE”: A Case Study in Using iPads to Promote Active Learning

In order to encourage more active learning in the library classroom, the college librarians at the Tidewater Community College/City of Virginia Beach Joint-Use Library turned one of their library instruction classrooms into a dynamic and flexible space using movable seating and iPads. This article explores the reasons for making such a change, the benefits of doing so, how the new classroom has affected librarians' teaching methods, and gives specific information about apps used for class activities.     

基于案例分析金字塔模型的主动运维案例体系建设

针对传统运维案例在经验共享和处置效率方面的不足及运维领域同类事件重复发生概率高、处置差异大的情况,提出一种案例分析金字塔模型,使用基于向量化解析和知识分层提取的素材库构建方法,实现由生产运维操作标准库、生产运行异常事件库到案例素材库再到案例教学库的自动生成转变,并以金字塔模型为基础,通过引入改进的趋势预测分析方法、案例推理"5R"模型和"4S"案例教学模式完善预警预测、辅助决策、案例教学相关应用,建立主动运维案例体系。实践结果表明,通过整个体系的推行,改变了企业信息系统运维被动应付的局面,同类事件占比逐年降低,事件响应时间和处置时间明显缩短,运维服务质量大幅提升。     

Performance of estimating depth in projection based stereoscopic virtual display

Accurate distance estimation is essential for effective user interaction with objects appearing in the virtual space. Research has shown that the distance estimation in the virtual space is not as accurate as that in the real world. The inaccuracy phenomenon is almost exclusively documented for estimating objects appearing straight ahead of the eye. A collection of the accuracy data for targets located in different angles of view in the visual field may be useful in aiding the design of user‐virtual object interaction. This study collected the object to object distance estimation accuracy for targets displayed stereoscopically. There are five horizontal and two vertical viewing angles and three depths, resulting in a total of 30 locations in the virtual space. The distance estimation for any of the 30 object pairs were performed with or without the aid of spatial cues. Significant factors influencing the accuracy and time of distance estimation were identified. Implications of the finding were discussed with respect to the stereoscopic display environment.     

Food-water security and virtual water trade in the Middle East and North Africa

The purpose of this study is to analyze the political economy of food-water security in the water-scarce Middle East and North Africa region. The study deploys the lens of virtual water trade to determine how the region's economies have met their rising food-water requirements over the past three decades. It is shown that the region's water and food security currently depend to a considerable extent on water from outside the region, ‘embedded’ in food imports and accessed through trade. The analysis includes blue (surface and groundwater) and green water resources.     

煤炭自动化装车系统数据回传技术研究

针对部分煤炭自动化装车系统因通信不便而无法及时回传数据的问题,提出了基于3G模式的自动化装车系统数据回传技术:采用CDMA2000实现自动化装车系统对公网的无线接入,通过OPC服务器实现上位机与现场生产系统PLC之间的数据收发,采用数据收集软件Transaction Manager完成OPC服务器和数据库之间的衔接。     

面向虚拟试验的可视化应用生成工具研究与实现

虚拟试验能够很好地辅助实物试验,缩短型号研制周期,降低研制费用;虚拟试验应用工程是开展虚拟试验的基础,基于GEF图形编辑器,研究并实现了一种面向虚拟试验可视化应用生成工具,具有可视化应用工程编辑、应用工程框架代码生成等功能;支持在可视化界面中定义VOM图元和APP图元之间的发布、订阅关系,最终生成应用工程框架,并通过应用实例验证了该可视化应用生成工具的实用性,较好地提高了虚拟试验应用工程的开发效率.     

基于Modbus RTU的虚拟仪器风洞电机温度监控系统开发

为监测风洞运行过程中动力系统电机温升状态,使其工作性能和绝缘等级处于合理范围,应用研华ADAM-4015模块对置于风洞6 KV高压电机相绕组与前后轴内的Pt100热电阻进行测量,本地PLC通过串口ModbusRTU协议与研华模块通讯获得电机实时温度,上位机虚拟仪器LabVIEW软件通过以太网OPC通讯实时获得PLC内电机温度值,实现了高压电机安全精确的隔离测量,以及本地、远程多个节点的温度实时监控、报警和安全联锁;实验结果表明,系统在-50～150℃内,可达到±0.1％精度,对最大功率下动力系统温升数据和特性曲线的获取实现了工作状态的分析预测,为安全互镇提供了控制依据.