事物分类和数据库解决方案

文章介绍了事物分类,结合实例分析了数据库表字段内容的表示、合并字段的解决方法及其相应算法。针对事物的不同分类,提出了对数据库字段内容采用排序字符与实际全称相结合的表示方法,从而实现既可根据排序字符有效控制排序,又可取出字段的实际全称,直接将其显示在新闻页面中。该数据库解决方案有效地降低了编程复杂性,提高了新闻显示速度,已将其成功地用于即时新闻公布系统的数据库设计和查询处理。     

An experimental study on the role of 3D sound in augmented reality environment

Investigation of augmented reality (AR) environments has become a popular research topic for engineers, computer and cognitive scientists. Although application oriented studies focused on audio AR environments have been published, little work has been done to vigorously study and evaluate the important research questions of the effectiveness of three-dimensional (3D) sound in the AR context, and to what extent the addition of 3D sound would contribute to the AR experience.

Thus, we have developed two AR environments and performed vigorous experiments with human subjects to study the effects of 3D sound in the AR context. The study concerns two scenarios. In the first scenario, one participant must use vision only and vision with 3D sound to judge the relative depth of augmented virtual objects. In the second scenario, two participants must cooperate to perform a joint task in a game-based AR environment.

Hence, the goals of this study are (1) to access the impact of 3D sound on depth perception in a single-camera AR environment, (2) to study the impact of 3D sound on task performance and the feeling of ‘human presence and collaboration’, (3) to better understand the role of 3D sound in human–computer and human–human interactions, (4) to investigate if gender can affect the impact of 3D sound in AR environments. The outcomes of this research can have a useful impact on the development of audio AR systems, which provide more immersive, realistic and entertaining experiences by introducing 3D sound. Our results suggest that 3D sound in AR environment significantly improves the accuracy of depth judgment and improves task performance. Our results also suggest that 3D sound contributes significantly to the feeling of human presence and collaboration and helps the subjects to ‘identify spatial objects’.     

Unsupervised image segmentation using a simple MRF model with a new implementation scheme

A simple Markov random field model with a new implementation scheme is proposed for unsupervised image segmentation based on image features. The traditional two-component MRF model for segmentation requires training data to estimate necessary model parameters and is thus unsuitable for unsupervised segmentation. The new implementation scheme solves this problem by introducing a function-based weighting parameter between the two components. Using this method, the simple MRF model is able to automatically estimate model parameters and produce accurate unsupervised segmentation results. Experiments demonstrate that the proposed algorithm is able to segment various types of images (gray scale, color, texture) and achieves an improvement over the traditional method.     

Isotropic Energies, Filters and Splines for Vector Field Regularization

The aim of this paper is to propose new regularization and filtering techniques for dense and sparse vector fields, and to focus on their application to non-rigid registration. Indeed, most of the regularization energies used in non-rigid registration operate independently on each coordinate of the transformation. The only common exception is the linear elastic energy, which enables cross-effects between coordinates. Cross-effects are yet essential to give realistic deformations in the uniform parts of the image, where displacements are interpolated.In this paper, we propose to find isotropic quadratic differential forms operating on a vector field, using a known theorem on isotropic tensors, and we give results for differentials of order 1 and 2. The quadratic approximation induced by these energies yields a new class of vectorial filters, applied numerically in the Fourier domain. We also propose a class of separable isotropic filters generalizing Gaussian filtering to vector fields, which enables fast smoothing in the spatial domain. Then we deduce splines in the context of interpolation or approximation of sparse displacements. These splines generalize scalar Laplacian splines, such as thin-plate splines, to vector interpolation. Finally, we propose to solve the problem of approximating a dense and a sparse displacement field at the same time. This last formulation enables us to introduce sparse geometrical constraints in intensity based non-rigid registration algorithms, illustrated here on intersubject brain registration.     

一种简单适用的加油装置在液压挖掘机上的应用

介绍了液压挖掘机加油系统的改进过程,通过在液压挖掘机的先导泵和柴油箱之间加入齿轮泵,齿轮马达等装置,使机器实现自动加油;并且加入光控或声控系统,提高机器加油的自动化水平,提高生产效率.     

有限元法在标准电容器电场计算中的应用

本文在分析国外标准电容器有关资料和多年来积累的研究和制造500kV及以下标准电容器经验的基础上，对高压标准电容器的绝缘结构进行了大量的研究工作，并用FORTRAN语言编制了有限元法进行标准电容器电场分析和计算的软件。该软件可用于对标准电容器电场的分析计算和优化设计。是研究开发高压标准电容器的有效工具。     

全数字伺服系统中相序故障自恢复功能的实现

针对永磁同步电机的伺服控制系统,分析了由电机相序的错接造成的启动故障,并对故障情况进行了归类。文中介绍了一种使用F240DSP控制芯片实现电机转子定向控制的方法。在光电编码盘角度反馈信号的帮助下,采用定子电压定向控制技术可准确地判断电机的三相连接方式,并通过软件调整驱动器的输出相序,以实现故障的自恢复功能。实验表明,电机在发生相序故障时,可快速地自恢复并完成启动,它可用于伺服控制系统。     

高压输电线路用复合绝缘子电位和电场分布的计算与改善

采用模拟电荷法和有限元法计算高压线路用复合绝缘子的电场分布和电位分布，讨论了改善复合绝缘子电场和电位分布的措施。为验证计算结果，还进行了复合绝缘子的电位分布试验。     

应用矩量法计算变电站内的空间电磁场

基于矩最法，提出了一种适合于变电站内开关操作时母线、设备间连线、架空线路产生的电磁场的计算方法，可以应用于变电站内较高频率分量的电磁场计算。应用文中计算方法与给出的计算方法分别对同一算例进行计算，其计算结果均一致，验证了文中方法的有效性。最后，借助于快速傅立叶变换，应用文中计算方法对某500kV变电站开关合闸操作时空载母线上的电流波过程和空间瞬态电场分布进行了预测计算，计算结果被应用于该变电站保护小室的屏蔽设计。     

PS 类Bent函数的一种构造方法

PS 类bent函数类是所有2^(n/2)-1或2^(n/2)-1+1个Fⁿ₂的"不交的" n 2 维子空间的指示函数的模2和所组成的函数的集合.这些函数具有很好的代数结构并在密码学中有很多应用.如何来刻画 PS bent函数的代数范式一直是公开的难题.构造 PS 类bent函数关键在于如何将Fⁿ₂划分为2^n/2+1个 n 2 维子空间.本文给出一种划分的方法,从而构造出 PS 类bent函数,并给出了对应的代数范式.