虚拟现实在无人驾驶地铁中的应用浅析

虚拟现实(Virtual Reality,VR)在近几年来在消费电子领域得到迅猛发展,得到学术界、工业界的广泛关注.从虚拟现实发展背景入手,简单介绍虚拟现实的发展现状和技术发展趋势.同时,结合目前先进的无人驾驶地铁技术,探讨了虚拟现实在轨道交通行业中的典型应用,一方面为虚拟现实中的关键技术找到了新的实际应用,另一方面,为无人驾驶地铁中的系统工程问题提供了新的解决思路和技术方案.     

基于UDK的虚拟现实技术在三维虚拟数字校园中的应用与研究

数字化校园虚拟漫游系统是数字化校园建设计划的核心平台。本文首先对目前主流的虚拟可视化开发工具作了介绍,并结合当今最流行的游戏引擎UDK（Unreal Development Kit）和三维设计软件3ads Max的虚拟现实技术问题进行了研究,以无锡城市职业技术学院校区为原型,运用三维设计软件3ads Max仿真技术建立了的虚拟校园三维模型。采用游戏引擎UDK（Unreal Development Kit）与SQL server后台数据库连接、实景拍摄与虚拟建筑相结合的方式,设计并实现了实时三维虚拟校园漫游系统的路径自动漫游、自主漫游、楼宇查询和鹰眼鸟瞰等功能。设计并实际运用结果表明,使用三维场景中烘焙贴图的制作运用UDK引擎技术改进的场景优化技术,系统运行效率得以很好的提高,甚至在普通PC机上实时运行时也很流畅和稳定。     

虚拟现实视频处理与传输技术

虚拟现实(VR)是当前视频领域研究热点.介绍了VR视频内容制作以及终端显示技术现状,分析了基于用户视点的VR视频处理关键技术,最后探讨了VR视频传输模式及其对承载网络的需求.     

基于虚拟现实的集装箱堆场可视化设计与研究

鉴于当前物流业的飞速发展以及集装箱堆场管理在整个物流枢纽中的重要地位,结合以Multigen Creator和Vega Prime为代表的虚拟现实技术,提出将集装箱堆场三维可视化并进行研究与设计。实现堆场集装箱二、三维可视化,箱体管理、调度、查询、操控过程等人机交互可视化,以及堆场场景搭建及漫游进而增加沉浸感。从而提高集装箱堆场的管理水平,运转效率和人机和谐度。     

虚拟现实技术在高职教育机电类专业课程中的应用

首先,文章提出一种有效提高教学质量的方法,介绍虚拟现实技术的特点;其次,论述虚拟现实技术在电机、供配电技术、机械制图等机电类专业教学改革中的应用;最后,总结出虚拟现实技术应用在机电类教学中有明显的优点以及存在的现实问题。     

研究基于并行渲染的虚拟现实开发平台设计与实现

在设计三维VR场景时需要依赖可视化的开发平台,设计开发平台时应注重提高软件运行速度,确保硬件接口与软件接口相互匹配,维持虚拟环境共享的一致性,能够及时更新网络协议与升级软件功能,保证VR系统具有兼容性的特点.     

Organic Haptics: Intersection of Materials Chemistry and Tactile Perception

The goal of the field of haptics is to create technologies that manipulate the sense of touch. In virtual and augmented reality, haptic devices are for touch what loudspeakers and RGB displays are for hearing and vision. Haptic systems that utilize micromotors or other miniaturized mechanical devices (e.g., for vibration and pneumatic actuation) produce interesting effects, but are quite far from reproducing the feeling of real materials. They are especially deficient in recapitulating surface properties: fine texture, friction, viscoelasticity, tack, and softness. The central argument of this progress report is that in order to reproduce the feel of everyday objects, molecular control must be established over the properties of materials; ultimately, such control will enable the design of materials which can change these properties in real time. Stimuli‐responsive organic materials, such as polymers and composites, are a class of materials which can change their oxidation state, conductivity, shape, and rheological properties, and thus might be useful in future haptic technologies. Moreover, the use of such materials in research on tactile perception could help elucidate the limits of human tactile sensitivity. The work described represents the beginnings of this new area of inquiry, in which the defining approach is the marriage of materials science and psychology.     

The role of affordance in the experience of virtual reality learning: Technological and affective affordances in virtual reality

As virtual reality becomes more and more mainstream, the role of affordances in virtual environments becomes an important question. The goal of this study is to explicate users’ motivational affordances and examine how they influence the acceptance of a virtual reality learning environment (VLE). It examines how motivational affordances in an educational virtual reality (VR) system affect user experience to track and achieve goals for users. A multimixed approach was used by combining qualitative methods and a quantitative survey. First, a critical incident technique was used to explore a range of affordance factors related to VLE. Second, based on the affordance factors identified from the qualitative methods, a survey was conducted to examine the effects of affordance on user cognitive processes and the influence of affordance on the learning process. The results of the user model confirmed the heuristic role of presence and immersion affordance regarding their underlying link to educational affordances, such as empathy and embodied cognition. The findings imply the embodied cognition process of VLE in which technological qualities are shaped by users’ perception and context. The results establish a foundation for VR technologies through a heuristic assessment tool from a user-embodied cognitive process. They confirm the validity and utility of applying affordances to the design of VR as a useful concept and prove that the optimum mix of affordances is crucial to the success of VR design.     

Industrial intelligent network: deepening and upgrading of industrial Internet

Manufacturing founds a major pillar of the national economy. The international community generally agrees that the core of the new wave of manufacturing upgrade is to achieve intelligent manufacturing. For this reason, the concepts of “Industrial Internet” and “Industry 4.0” was proposed by united state, Germany and other technologied, and formulated manufacturing development strategies suited to their national conditions. “Made in China 2025” was proposed by China which determines the development direction based on intelligent manufacturing in the level of national development strategy. Based on the status quo and technological advantages of China's industrial intelligent manufacturing, and aiming to help large, medium and small-sized production enterprises achieve industrial intelligence in a flexible, smooth and cost-controllable manner, the concept of “industrial intelligent network” was proposed to integrate the conditions and advantages in aspects of China's information infrastructure construction, cognitive identification, artificial intelligence, etc., to build an industrial intelligent network, to provide industrial intelligent services to large, medium and small-sized enterprises, so that production enterprises within a broader scale can benefit from intelligent manufacturing with lower costs.     

宽带 U 型槽矩形贴片微带天线设计

提出并设计了一种宽带广角覆盖的波束扫描折叠式反射阵列（folded reflect array,FRA）天线. 为了在宽带范围内以及较宽的波束覆盖范围（beam coverage range,BCR）内获得较低的扫描损耗,提出一种考虑照射权重因子、截获功率权重因子以及频率权重因子的多波束优化方法;为了降低FRA天线的剖面,采用小尺寸贴片天线作为馈源,将其与单层反射板集成在一起. 设计了一个尺寸为264 mm×264 mm、工作在Ku波段的11波束扫描的FRA天线,仿真验证本文所提设计方法的有效性,结果表明：该设计在13.5~16.5 GHz的宽带范围内,实现了3 dB波束可覆盖−28°~28°范围,中心频率处最大增益为26.6 dBi,口径效率范围为14%~20.9%,所设计的共口径FRA天线可以获得相当平坦的增益,扫描损耗都在3 dB以内. 该天线具有覆盖范围广、覆盖带宽宽、集成度高、增益高、口径效率高等优点,在无线通信、雷达成像和目标识别等领域具有广阔的应用前景.     

Toward energy‐proportional Internet core networks: an energy‐minimized routing and virtual topology design for Internet protocol layer

With the exponential growth of Internet traffic, the energy consumption issue of core networks is increasingly becoming critical. Today's core networks are highly underutilized most of the time because of the over‐provisioning and redundancy dimensioning, which results in severe energy inefficiency. In previous work, many non‐deterministic polynomial‐time hard mathematics formulation models have been proposed to minimize the energy consumption of core networks. However, effective heuristics are needed to solve these models in medium/large‐size networks. This work studies the energy‐minimized routing and virtual topology design problem of the power‐hungry Internet protocol (IP) layer in core networks, aiming to achieve an energy‐proportional IP layer by exploiting the variation of traffic with hours to reconfigure virtual topology and reroute traffic. We formulate energy‐minimized routing and virtual topology design as an Integer linear programming problem and propose a LR algorithm, a heuristic based on the Lagrangian relaxation, to solve this problem in a polynomial‐time. The simulation results indicate that the LR algorithm outperforms the best previous algorithm and can achieve a near energy‐proportional IP layer with significant power saving. Furthermore, a detailed analysis of simulation results is conducted, which suggests a design principle of network equipment to facilitate the power saving. Copyright © 2013 John Wiley & Sons, Ltd.     

The impact of innovation and gratification on authentic experience,subjective well-being,and behavioral intention in tourism virtual reality: The moderating role of technology readiness

Despite the increasing amount of attention paid to virtual reality (VR) tourism and the rising importance of VR tourism, a theoretically integrated model of behavior has not been developed. To fill this void, we build and test a framework based on both innovation diffusion and uses and gratifications theories to explain why people participate in VR tourism. The moderating role of VR tourists’ technology readiness (optimism and innovativeness) between subjective well-being and behavioral intention is also examined. Results demonstrate that authentic experience and subjective well-being are affected by simplicity, benefit, compatibility (attributes of innovation diffusion), informativeness, social interactivity, and playfulness (uses and gratifications attributes). Behavioral intention is more positively influenced by subjective well-being than by authentic experience. The moderating role of technology readiness between subjective well-being and behavioral intention is stronger in individuals with high optimism and innovativeness than their counterparts with low optimism and innovativeness.     

气液两相流三维测量中虚拟立体视觉传感器的优化设计与实验

针对高速动态的气液两相流动对象,基于双目体视原理,采用单台高速摄像机和反射镜组,对虚拟立体视觉传感器进行了优化设计;对气泡发生装置中竖直向上的气泡特征参数进行三维测量。建立虚拟立体视觉传感器三维测量模型,综合考虑实际视场、传感器结构和测量误差等因素,通过结构参数对3方面性能影响的仿真分析,最终确定传感器的结构参数。实验结果表明,传感器测量空间距离误差优于0.14 mm,相对误差优于0.49%,适于气液两相流动态测量,可以实现气泡运动的三维重建。     

Evidence and Effect of Photogenerated Charge Transfer for Enhanced Photocatalysis in WO3/TiO2 Heterojunction Films: A Computational and Experimental Study

Semiconductor heterojunctions are used in a wide range of applications including catalysis, sensors, and solar‐to‐chemical energy conversion devices. These materials can spatially separate photogenerated charge across the heterojunction boundary, inhibiting recombination processes and synergistically enhancing their performance beyond the individual components. In this work, the WO₃/TiO₂ heterojunction grown by chemical vapor deposition is investigated. This consists of a highly nanostructured WO₃ layer of vertically aligned nanorods that is then coated with a conformal layer of TiO₂. This heterojunction shows an unusual electron transfer process, where photogenerated electrons move from the WO₃ layer into TiO₂. State‐of‐the‐art hybrid density functional theory and hard X‐ray photoelectron spectroscopy are used to elucidate the electronic interaction at the WO₃/TiO₂ interface. Transient absorption spectroscopy shows that recombination is substantially reduced, extending both the lifetime and population of photogenerated charges into timescales relevant to most photocatalytic processes. This increases the photocatalytic efficiency of the material, which is among the highest ever reported for a thin film. In allying computational and experimental methods, this is believed to be an ideal strategy for determining the band alignment in metal oxide heterojunction systems.     

Simulation of SiGe:C HBTs using neural network and adaptive neuro-fuzzy inference system for RF applications

In this article, the small-signal equivalent circuit model of SiGe:C heterojunction bipolar transistors (HBTs) has directly been extracted from S-parameter data. Moreover, in this article, we present a new modelling approach using ANFIS (adaptive neuro-fuzzy inference system), which in general has a high degree of accuracy, simplicity and novelty (independent approach). Then measured and model-calculated data show an excellent agreement with less than 1.68?×?10^?5% discrepancy in the frequency range of higher than 300 GHz over a wide range of bias points in ANFIS. The results show ANFIS model is better than ANN (artificial neural network) for redeveloping the model and increasing the input parameters.     

Digital inequalities and implications for social inequalities: A study of Internet penetration amongst university students in South Africa

International and national data sources confirm the limited access to the Internet in South Africa. However, there is a need to study how this limited access is distributed amongst population groups in the country. This study investigates the pattern of Internet access amongst university students in South Africa. University students are a relevant population group for studying technology penetration; this population is a generation born in the current era of digital revolution, they are presumably early adopters of technology and are adept in using them. A survey conducted in ten South African universities reveals that beyond publicly available access on campuses – with its attendant constraints, personal/household Internet access is a challenge and it reflects a pattern of inequalities in South Africa. Bearing in mind that social and economic exclusion is the biggest challenge for South Africa, this study reveals that digital inequalities amongst students replicate the pattern of social inequalities in the country. This exacerbates existing social inequalities, specifically amongst university students in South Africa, with certain categories of students being disproportionately disadvantaged.     

Probing the growth of β‐FeSi2 nanoparticles for photovoltaic applications: a combined imaging and spectroscopy study using transmission electron microscopy

The microstructure of β‐FeSi₂ nanoparticles grown using magnetron sputtering on Si has been examined using various electron microscopy techniques. FeSi₂ nanoparticles as small as ∼4 nm are found embedded in Si after growth using co‐sputtering of FeSi₂ and Si, followed by rapid thermal annealing (RTA). The formation of nanoparticles and its variation in density with Fe content is discussed in terms of phase separation. Our study shows that the size and density of the nanoparticles as well as the extent of Fe diffusion into sputtered Si and substrate can be controlled by controlling the Fe content in the co‐sputtered film. Copyright © 2011 John Wiley & Sons, Ltd.