Efficient self-certified proxy CAE scheme and its variants

Elaborating on the merits of proxy signature schemes and convertible authenticated encryption (CAE) schemes, we adopt self-certified public key systems to construct efficient proxy CAE schemes enabling an authorized proxy signer to generate an authenticated ciphertext on behalf of the original signer. To satisfy the requirement of confidentiality, only the designated recipient is capable of decrypting the ciphertext and verifying the proxy signature. A significant advantage of the proposed schemes is that the proxy signature conversion process takes no extra cost, i.e., when the case of a later dispute over repudiation occurs, the designated recipient can easily reveal the ordinary proxy signature for the public arbitration. If needed, the designated recipient can also convince anyone that he is the real recipient. In addition, integrating with self-certified public key systems, our schemes can earn more computational efficiency, since authenticating the public key and verifying the proxy signature can be simultaneously carried out within one-step.     

Special issue on omnidirectional vision and its applications

Machine Vision and Applications -     

Design and development of new control technique for standalone PV system

A Sub-Maximum Power Point Tracking (S-MPPT) algorithm improves the performance of Photo Voltaic (PV) systems. This S-MPPT is used in single-phase PV system to test the tracking accuracy and its impact on the consistency of the whole system. Single phase PV Deadbeat Scheduler is proposed in this paper. The Deadbeat scheduler is a linear system. It initializes each initial state of the system to zero in shortest time possible. A single phase PV structure configuration is proposed to decrease the partial shading effect by changing the parameters of S-MPPT control algorithm. Thus, voltage sensor based S-MPPT algorithm through voltage reference control technique with the help of controller is developed for minimizing the tracking time and steady state oscillations. Selection of the objective function to mitigate the drawbacks associated with voltage sensor based algorithm for a decrease in solar irradiance are also demonstrated. The proposed MPPT algorithm with the designed controller is tested for a step change in irradiance from 270 to 480 W/m2 with a perturbation time of 20 ms and ∆V = 0.5 V (perturbation of voltage). From the simulation results, the proposed method with S-MPPT plus deadbeat control algorithm is compared with other existing algorithms.     

CAE技术的全球化

崛起于航空航天的CAE(Computer Aided Engineering)技术今天已经成为很多行业进行科学研究、技术创新以及产品设计的重要技术手段.几十年前欧美借助全球领先的航空航天中的计算分析技术以及成熟的商业运营模式,成功地将计算机分析与仿真技术制成便于操作的商业软件包,使其应用范围和求解问题的能力空前增长.近10年来,CAE技术已经通过软件运营商和商业流通渠道,成为发达国家结构分析、产品造型、新材料开发、医药化工、人机工程等各领域普遍采用的数字化虚拟仿真平台.     

Quadtree-based genetic algorithm and its applications to computer vision

Many computer vision problems can be formulated as optimization problems. Presented in this paper is a new framework based on the quadtree-based genetic algorithm that can be applied to solve many of these problems. The proposed algorithm incorporates the quadtree structure into the conventional genetic algorithm. The solutions of image-related problems are encoded through encoding the corresponding quadtrees, and therefore, the 2D locality within a solution can be preserved. Examples addressed using the proposed framework include image segmentation, stereo vision, and motion estimation. In all cases, encouraging results are obtained.     

光场成像技术及其在计算机视觉中的应用

目的 光场成像技术刚刚在计算机视觉研究中展开初步应用,其相关研究比较零散,缺乏系统性。本文旨在系统介绍光场成像技术发展以及其应用在计算机视觉研究中有代表性的工作。方法 从解决计算机视觉问题的角度出发,4个层面讨论光场成像技术最近十年的研究工作,包括:1)主流的光场成像设备及其作为计算机视觉传感器的优点与不足;2)光场相机作为视觉传感器的标定、解码以及预处理方法;3)基于4维光场的图像渲染与重建技术,以及其如何促进计算机视觉研究;4)以4维光场数据为基础的特征表达方法。结果 逐层梳理出光场成像在求解视觉问题中的优势和局限,分析其中根本性的原理与掣肘,力图总结出亟待解决的关键问题以及未来的发展趋势。结论 作为一种颇具前景的新型计算机视觉传感器技术,光场成像技术的研究必将更为广泛和深入。研究应用于计算机视觉的光场成像技术将有力的引导和促进计算机视觉和光场成像技术协同发展。     

深度学习及其在计算机视觉领域中的应用

首先回顾了计算视觉发展的历史,介绍了神经元、多层感知机和反向传播等人工神经网络的基本知识以及卷积神经网络的发展史及其卷积、池化等基本操作;讨论了AlexNet、VGGNet、GoogLeNet和ResNet等经典卷积神经网络结构,并重点介绍了CapsNet;总结了卷积神经网络在图像分类、语义分割、目标检测以及图像生成等领域的研究进展;最后提出了卷积神经网络研究所面临的挑战以及对CapsNet未来研究的展望。     

CAE技术回顾与展望

计算机技术的进步和企业的需求促进了CAE的迅速发展。文章对CAE进行了较全面的概述,首先介绍了产生背景与发展历程,然后分析了CAE的发展与应用现状,最后阐述了其未来发展趋势。     

Pervasive and standalone computing: the perceptual effects of variable multimedia quality

The introduction of multimedia on pervasive and mobile communication devices raises a number of perceptual quality issues; however, limited work has been done examining the three-way interaction between use of equipment, quality of perception and quality of service. Our work measures levels of informational transfer (objective) and user satisfaction (subjective) when users are presented with multimedia video clips at three different frame rates, using four different display devices, simulating variation in participant mobility. Our results will show that variation in frame rate does not impact a user's level of information assimilation, however, does impact a users’ perception of multimedia video ‘quality’. Additionally, increased visual immersion can be used to increase transfer of video information, but can negatively affect the users’ perception of ‘quality’. Finally, we illustrate the significant affect of clip-content on the transfer of video, audio and textual information, placing into doubt the use of purely objective quality definitions when considering multimedia presentations.     

实时卫星导航接收机在独立DSP平台上的设计实现

针对目前卫星导航接收机通常需要依赖FPGA芯片或ASIC芯片,功能扩展升级困难的问题,提出了基于独立DSP芯片的模块化卫星导航接收机平台的构建方法,并研究了中频卫星信号的实时采集、程序和数据的分配与存储、线程调度管理技术.在此基础上,以TI公司的TMS320C6416芯片为实例,设计实现了实时软件接收机样机.实验结果表明,依照该方案设计的平台能够很好地实现实时卫星导航软件接收机的功能.     

CAE在中国及"力学机械化"

中国的经济发展模式准备从制造经济转向创新经济的时候,意味着CAE在中国已经可以找到自己巨大的发展空间.中国是一个航天大国,航天工业的迅速发展奠定了CAE在中国的基础;同时,中国又是一个制造大国,CAE所引航的先进虚拟制造技术必然在未来制造创新技术中起着决定性的作用.     

高分子材料PVT特性在线测试技术及其在注射成形CAE仿真中的应用

针对离线测试方法无法真实反映注射成形过程中高分子材料实际PVT参数的变化历程,利用这些参数进行CAE仿真会产生较大误差的问题,研发基于注塑机的高分子材料PVT关系在线测试技术和装置.分别采用在线测试和离线测试装置获得PVT参数进行注射成形CAE模拟,并将模拟结果与实际注射成形样品进行对比.结果表明利用在线测试PVT参数模拟得到的制品收缩率更接近实际值.以在线测试技术为基础建立的PVT关系状态方程可显著提高数值模拟精度,为高分子材料成形加工CAE仿真分析和先进制造提供重要技术支撑.     

Evolutionary aspects of CAE systems

Computer-aided engineering (CAE) comprises several disciplines of computer application to engineering problems. From a systems analysis point of view, the different stages of the development of a new product may be mapped on to disciplines such as computer-aided design, computer-aided manufacturing, and others. These constituents of CAE are briefly discussed, with emphasis on the need for their integration. A short review of the development of CAE systems technology is also given. Present trends and needs for more research are indicated.     

基于独立DSP平台的实时卫星导航接收机的设计

以TI公司的TMS320C6416芯片为例,设计实现了基于独立DSP芯片的通用卫星导航接收机平台,说明了如何通过单独的DSP平台实现中频卫星信号的采集、程序和数据的存储、线程调度等功能,以及如何支持多星座卫星导航接收机扩展。实验结果表明,根据本方案实现的平台能够很好地实现实时卫星导航软件接收机的功能。     

游戏梦工场

“大话西游”里面有句经典的台词：“我猜中了开头，可是我猜不着这结局。”夕阳武士这番话可以带给观众无限的遐想，观众记住了这部电影。制作游戏和制作电影一样，一定要抓住玩家的心态，了解玩家的期望，适当留下悬念，这样才能吸引玩家。那玩家期望的到底是什么呢？     

游戏梦工场

二，玩家的需要 大学时的一个舍友QQ签名有点意思：“如果一个游戏设计师根本不知道玩家为什么要玩游戏，那他是在作梦而不是造梦。”这期．我就和大家。聊聊玩家为什么要玩游戏。     

游戏梦工场

上海某网络游戏运营商为了打击非法外挂．一夜封杀12万游戏玩家账号。其后，在该游戏运营商的组织下．百余名游戏玩家集体献血，其中半数被封账号的玩家因此而被“解封”。专家称以“解封”为条件鼓励玩家献血不妥。[编者按]     

The Radon transform and its application to shape parametrization in machine vision

A general method is presented that uses the Radon transform as a means of defining a two-dimensional transform space in which information about different, analytically defined shape primitives in an edge image space may be encoded simultaneously. Examples are given illustrating how the shape-indicative distributions within the transform space may be deduced. The results show that each set of coded information is transparent to any other and that each shape-indicative distribution may be located using a convolution mask peculiar to that distribution.