Reusable,lifelike virtual humans for mentoring and role-playing

Lifelike, interactive digital characters, serving as mentors and role-playing actors, have been shown to significantly improve learner motivation and retention. However, the cost of modeling such characters, authoring and editing their interactions, and delivering them over limited-bandwidth connections can be prohibitive. This paper describes a framework, authoring tools, and Web-based run-time environment that support the creation of training scenarios using digital virtual humans and other reusable 3D components. By conforming to the Humanoid Animation (H-Anim), Extensible 3D, and ADL Shareable Content Object Reference Model specifications, these 3D components are designed to promote reuse and interoperability at several levels. Recently, these software tools were used to develop prototype lessons in foreign language and cultural familiarization for use at the Defense Language Institute Foreign Language Center. These lessons include simulations in which the student, taking the role of a US soldier, interacts with the local population of a foreign culture in authentic situations, using both English and the local dialect. Digital virtual humans are used to represent not only the soldier, and the role-playing actors; but also a mentor who reviews language and cultural learning points, and provides remediation. Using these prototype lessons as examples, we review the potential advantages of the technology in other training applications.     

BW-RAID系统的重构技术及优化研究

高效的重构技术可以有效地提高系统数据恢复时的性能,减少数据的恢复时间。针对BW-RAID系统的结构特点,提出了系统数据卷数据优先重构的机制和对已重构数据请求重定向的方法,有效地提高了系统数据恢复时的对外服务性能。基于上面的机制和方法,同时利用数据恢复时的用户负载特点,采用热点和缓存数据指导数据重构以及用户请求辅助数据重构两种策略,进一步地提高了数据恢复时的性能和重构效率。     

微型直升机自主飞行辅助视觉系统研究

为了实现微型直升机自主飞行,论文设计了实时的计算机视觉系统。该系统包括机载上的硬件设备和软件算法,能够实现目标识别、特征点提取和位置估计。文中设计了特定图标,并主要依据颜色来进行快速识别。此外,通过检测4个共面的图像特征点,能够在单目单帧的基础上计算出直升机相对于特定目标的三维位置信息。视觉系统任务由位于机载上的IntelSitsang板来执行。由于受到板子运算能力的限制,每秒钟可以处理5帧160×120的彩色图像。飞行实验结果表明,该视觉系统的目标识别率高达93%,角点计算偏差小于3个像素,同时自身定位的三维位置坐标平均偏差为8cm、13cm和6cm。因此,该视觉系统通过精确自身定位,能够很好的辅助微型直升机完成自主悬停、起飞和降落等飞行任务。     

D型打结器架体的随机振动分析与结构优化

针对D型打结器架体易断裂、寿命短等问题,采用动力学与疲劳分析相结合的研究方法.基于模态-谐响应分析,得到架体应变幅值曲线.采用随机振动分析与Miner线性损伤累加法则对架体进行疲劳寿命分析,结果得出架体的疲劳寿命不高.设计架体四因素三水平的正交试验,对架体进行结构优化.结果 表明优化后的架体疲劳寿命显著提高.     

Differences in wearer response to garments for outdoor activity

The performance of garments for outdoor activity was compared. Three fabrics, each in garments for the upper body, matched garment/wearer dimensions, were worn by 10 athletically 'well-trained' males under controlled conditions (hot 32 +/- 2 degrees C, 20 +/- 2% relative humidity (RH); cold 8 +/- 2 degrees C, 40 +/- 2% RH) with physical (instrumental) and sensory responses obtained during the trials. Differences in human responses to the fabrics/garments included heart rate, core temperature during run (hot, cold), rest (hot) and walk (cold), heat content of the body, humidity under garments during rest and run and time to onset of sweating. No such differences were identified for change in body mass, core temperature during walk (hot) and rest (cold), skin temperature, temperature of skin covered by the garment, humidity under the garments during walk or for any perceptions (thermal sensations, thermal comfort of torso, exertion, wetness). The garment in single jersey wool fabric performed best in both hot and cold conditions. Effects of garments on wearers are often related to properties of the fabrics from which the garments are made. This study shows that only some differences in fabric properties result in measurable thermophysiological and perceptual responses of the garment wearers and underlines the difficulty in predicting performance of garments/persons from laboratory tests on fabrics.     

单级倒立摆建模及其控制方法设计

单级倒立摆控制是一个即复杂而又对准确性、快速性要求很高的非线性不稳定系统控制问题。单级倒立摆数学模型的建立对研究其稳定性具有指导作用。用拉格朗日功能平衡法建立了倒立摆的刚体动力学方程,采用了LQR法对其进行了控制设计,并且进行了MATLAB仿真,结果表明此方法均可以成功控制倒立摆,使其稳定并具有良好的鲁棒性。     

应用谱直方图相似性的纹理图像分割研究

提出基于谱直图相似性的纹理图像分割算法,在提出的纹理分割算法中,无需选择种子点。首先通过使用一组滤波器来获取纹理图像的纹理特征,基于空域/频域的表示方法,使用谱直方图作为特征统计,然后利用x²统计特征度量谱直方图之间的相似性,得到初始分割,然后基于形态学骨架化的原理,对区域边界进行精确定位,得到最终的分割结果。实验结果验证了算法的有效性。     

虚拟MIMO传感器网络中一种联合网络效用和生存时间优化的分布式算法

虚拟(协作式)MIMO技术被认为是传感器网络中有效的节能解决方案之一,然而,现有虚拟MIMO传输策略的设计大多只关注如何有效降低网络能耗,而很少关注反映网络性能的其他指标,例如网络效用(Network Utility),该指标反映了网络数据采集和传输量的多少.为了联合优化网络效用和网络生存时间这两个网络性能参数.本文首先分析虚拟MIMO传输能耗特点,然后基于网络效用最大化(Network Utility Maximization)思想对虚拟MIMO传感器网络进行联合网络生存时间和网络效用的优化建模.在该模型的求解过程中,通过使用对偶分解技术将原需要集中计算的优化问题分解为可以在不同节点上进行计算的子优化问题,并得出一种联合优化网络效用和生存时间的分布式优化算法.该算法的仿真结果显示,网络中的虚拟MIMO节点仅需要交互邻居节点信息,通过有限次的迭代计算,就能收敛到全局最优的发送速率以及功率值.从而使系统总的效用和网络生存时间之间能够达到帕累托(Pareto)最优平衡.     

iDCX 51在Webit上的设计与实现

Webit是一个独立的、低成本的网络服务器,由东大新业技术股份有限公司研制成功.iDCX 51是Intel公司开发的实时操作系统,在工业控制等领域已成功应用,为使其能在Webit中也能够运行,以增强Webit的性能,对此本文以Webit内部单片机AT90S8515为例介绍iDCX 51往Webit中移植的设计与实现,并对移植后的时间性能进行了测试与对比分析,得知其任务切换时间与最大中断禁止时间这两项关键的时间性能指标分别减少33.3%和31.9%,表明系统移植后实时性得到了提高.     

PIC单片机在逆变电源系统中的应用

本文介绍了一种以高性能dsPIC30F2010控制器为内核的逆变电源系统,阐述了它的工作原理、硬件组成及软件设计。该逆变电源系统具有硬件电路简单、体积小、成本低等优点。经试验表明:电源动态响应速度快,输出波形失真小,可靠性高。