大规模室外场景漫游中入口问题的研究

提出一种综合适用于室内外场景的、添加更多细节的快速漫游方法.将室外场景漫游的预处理四叉树中加入层级入口的视载体,从而可以和室内场景漫游的BSP算法有机地结合起来,以期可以成为综合性场景的一种漫游和渲染的解决方案.     

虚拟场景自动漫游的路径规划算法

采用机器人学中的运动规划算法得到大致路径,并对路径进行数次优化得到最终路径．用户无需直接控制位置与视角,仅需给出目标点,系统就会自动地完成整个漫游;漫游过程中摄像机不会与物体发生碰撞,并且给出的画面符合一些基本的美学原则．该算法基于场景的层次分解,并采用了高效的路径平滑与视角规划方法,使得整个规划过程需要的时间非常少,提高了算法的实用性．     

场景分割算法及其在实时漫游系统中的应用

实时漫游中对实时性的要求很高,但通常情况下场景绘制速度很难满足实际需求,基于包络球检索和八叉树分割的思想,提出一种基于场景分割的加速绘制算法,并对绘制过程中探照灯的处理进行了探讨。     

城市轨道交通自动售检票系统顶层规划建设探讨

目前,城市轨道交通AFC系统基本都是采用传统的五层架构。传统的五层架构,较适用于线网建设规模较小、线路建设周期不密集的城市,而对于线网规模较大、同期建设线路较多的城市,无论从节省建设成本、提高经济效益,还是从运营管理需求方面,传统的架构都将面临着改造。郑州地铁根据线网建设的实际情况,结合云平台、大数据等新技术的快速发展和网络化建设、资源共享、统筹管理及线网化运营等方面的需求,提出了AFC系统的四层架构的设计理念。本文主要阐述郑州市轨道交通AFC系统顶层规划建设的发展历程、架构设计等,以此为其他地铁的建设规划过程提供参考。     

基于四叉树分割的连续LOD漫游地形绘制

针对大规模地形数据访问量大、场景渲染消耗内存大、实时渲染效率低的问题,提出了一种基于四叉树分割的连续LOD(层次细节)地形绘制方案,实现了多分辨率地形的快速绘制.视见体裁剪算法判断次数少,并结合四叉树分割过程,快速地对地形数据进行裁剪.采用与视点和地形粗糙度相关的分割评价系统,在预处理阶段对地形粗糙度误差进行计算,提升了地形实时绘制的速度:同时对分割标志位按位存储,使得内存占有率大幅减少.通过分割低分辨率节点边的方式,消除了节点间裂缝.算法运行效果良好,在普通PC机上即可达到较高的帧频率和较好的漫游效果.     

一个沉浸式场景漫游系统的构建

虚拟现实技术,是一种可以创建和体验虚拟环境的计算机系统技术,在军事、游戏、室内设计等诸多领域都有着广泛的应用。一个沉浸式的虚拟现实系统,可以让用户完全沉浸在虚拟世界中,得到与真实世界近似相同的感受。在高精度定位跟踪系统的辅助下,利用visual studio开发环境和3ds max、virtools软件构建了一个沉浸式场景漫游系统,并给出了一个游戏应用示例和一个室内设计应用示例。     

大规模三维地形场景实时漫游系统的构建

该文阐述了构建大规模三维地形模型的关键技术,包括地形分块技术、多分辨率模型管理技术、多级纹理贴图技术,给出了实时渲染时的动态调度与管理方法,并对在三维地形中显示文化特征做出一些探索和尝试。最后利用上述提出的技术,做了一些关于某一大规模三维地形实时漫游方面的实验,文中详细列出了这些实验结果。实验结果表明,采用该文提出的方法,可以在普通PC机上实现大规模三维地形场景的实时漫游。     

QuickWalk:一个大规模场景交互漫游系统

随着三维扫描与建模技术的飞速发展,三维场景的数据量急剧增大,无法一次性载入内存,而且难以进行交互绘制.研究开发了一个大规模外存场景的交互漫游系统QuickWalk,该系统集成了视点相关的层次细节技术、可见性剔除和场景数据的内外存调度,能够有效地减少运行时刻的内存需要,使CPU、GPU和I/O三者的效率得到充分发挥.实验表明,在保证场景绘制质量的前提下,该系统能够在目前普通的PC上实现大规模外存场景的实时显示和交互操纵.     

一个基于Vega的虚拟场景漫游系统

针对城市水环境仿真的需求,提出满足实际需要的漫游方式和碰撞检测方式。采用三维图形高层开发环境Vega软件作为开发平台。开发了符合水环境仿真需要的自动漫游方式;采用Vega软件自带的运动方式进行交互漫游,并采用了利用物理思路解决点在凸多边形内的算法对交互漫游进行范围限定。采用查找相邻物体的算法,对Vega软件自带的碰撞检测方法进行改进,从而提高了检测效率。这些方法已经成功地运用到了城市水环境仿真中,并取得了很好的效果。     

分布式三维实时漫游系统数据存储和调度方法研究

本文针对工作站多通道输出的分布式三维实时漫游系统,设计并实现了DEM和纹理数据的存储和调度方法,详细介绍了数据的分块存储,视点相关的可见区裁剪和细节层次的选择,并且介绍了预可见区数据的预调度和多通道输出可见区的分割。该方法能保证场景显示的平滑和连续性,能达到比较满意的帧率。     

A Theoretical Framework for Physically Based Rendering

In this paper we introduce the concept of the global reflection distribution function which allows concise formulation of the global illumination problem. Unlike previous formulations it is not geared towards any specific algorithm. As an example of its versatility we derive a Monte Carlo rendering algorithm that seamlessly integrates the ideas of shooting and gathering power to create photorealistic images.     

Swat: A system for detecting salient Wikipedia entities in texts

We study the problem of entity salience by proposing the design and implementation of Swat , a system that identifies the salient Wikipedia entities occurring in an input document. Swat consists of several modules that are able to detect and classify on‐the‐fly Wikipedia entities as salient or not, based on a large number of syntactic, semantic, and latent features properly extracted via a supervised process, which has been trained over millions of examples drawn from the New York Times corpus. The validation process is performed through a large experimental assessment, eventually showing that Swat improves known solutions over all publicly available datasets. We release Swat via an API that we describe and comment in the paper to ease its use in other software.     

影子模式:一种新的用于测试的设计模式

介绍了一种新的设计模式：用于测试面向对象程序的影子模式．它为每个使用它的对象生成一个影子对象,这种模式允许测试脚本无缝地嵌入到程序中,无需额外的测试驱动或测试插件。在测试过程中,测试用例可以调用影子对象作为测试插件,也可以调用真实的应用代码,测试脚本可以在运行时做出选择,这些概念将在模块测试和集成测试中分别举例说明。     

视频监控系统中运动目标的检测和阴影抑制

提出了一种室内静止摄像机条件下的运动目标检测和阴影抑制方法。该方法采用一种自适应的背景估计方法来实时更新背景,用基于概率分类法检测运动目标,并在联合HMMD色彩空间和光度特征来抑制阴影之后,用Sobel边缘检测来修正运动目标。实验结果表明,该方法能够有效地检测运动目标和抑制阴影。     

A generic multi-attribute analysis system

This paper describes a generic decision support system based on an additive multiattribute utility model that is intended to allay many of the operational difficulties involved in the multicriteria decision-making process. The system accounts for uncertainty about the alternative consequences and admits incomplete information about the decision-makers’ preferences, which leads to classes of utility functions and weight intervals. The additive model is used to assess, on the one hand, average overall utilities, on which the ranking of alternatives is based and, on the other, minimum and maximum overall utilities, which give further insight into the robustness of this ranking. When the information obtained is not meaningful enough so as to definitively recommend an alternative, an iteration process can be carried out by tightening the imprecise parameters and assessing the non-dominated and potentially optimal alternatives or using Monte Carlo simulation techniques to determine useful information about dominance among the alternatives.     

昆虫运动图像分割中的阴影消除算法

昆虫运动图像分割是昆虫步态提取、跟踪及分析的基础,根据昆虫运动图像中阴影点灰度小和色度保持稳定的特点提出一种适合室内运动检测的图像分割及阴影消除方法。先将当前帧图像与当前的背景图像对应像素点的像素值相除,比值小于1的点可能包括阴影和运动目标;然后计算比值小于1的点在RGB空间中的向量与对应背景点向量的夹角余弦。因为阴影色度保持不变,其夹角为0或极小,所以可将余弦接近1的点判为阴影。实验表明该方法简单有效,提取出来的昆虫前景图轮廓清晰,特征部分保持完整,为昆虫步态检测、分析及机器人步态规划提供支持。     

A dynamic and automatic traffic light control expert system for solving the road congestion problem

Traffic congestion is a severe problem in many modern cities around the world. To solve the problem, we have proposed a framework for a dynamic and automatic traffic light control expert system combined with a simulation model, which is composed of six submodels coded in Arena to help analyze the traffic problem. The model adopts interarrival time and interdeparture time to simulate the arrival and leaving number of cars on roads. In the experiment, each submodel represents a road that has three intersections. The simulation results physically prove the efficiency of the traffic system in an urban area, because the average waiting time of cars at every intersection is sharply dropped when the red light duration is 65 s and the green light time duration is 125 s. Meanwhile, further analysis also shows if we keep the interarrival time of roads A, B, and C, and change that of roads D, E, and F from 1.7 to 3.4 s and the interdeparture times at the three intersections on roads A, B, and C are equal to 0.6 s, the total performance of the simulation model is the best. Finally, according to the data collected from RFID readers and the best, second and third best traffic light durations generated from the simulation model, the automatic and dynamic traffic light control expert system can control how long traffic signals should be for traffic improvement.     

A robust web personal name information extraction system

Personal information extraction, which extracts the persons in question and their related information (such as biographical information and occupation) from web, is an important component to construct social network (a kind of semantic web). For this practical task, two important issues are to be discussed: personal named entity ambiguity and the extraction of personal information for a specific person. For personal named entity ambiguity, which is a common phenomenon in the fast growing web resource, we propose a robust system which extracts lightweight features with a totally unsupervised approach from broad resources. The experiments show that these lightweight features not only improve the performances, but also increase the robustness of a disambiguation system. To extract the information of the focus person, an integrated system is introduced, which is able to effectively re-use and combine current well-developed tools for web data, and at the same time, to identify the expression properties of web data. We show that our flexible extraction system achieves state-of-the-art performances, especially the high precision, which is very important for real applications.     

交通事故处理信息系统的设计与实现

交通事故处理在维护社会治安、保障公众安全以及促进社会经济的发展等方面扮演了一个极为重要的角色,实现交通事故处理的计算机化管理具有非常重要的现实意义。作为一个尝试,该文提供了一个从网络平台设计到软件系统开发的一体化解决方案。该方案已经成功地运用于浙江省交通事故处理信息系统的建设。     

A simple index rule for efficient traffic splitting over parallel wireless networks with partial information

Multi-path communication solutions provide a promising means to improve the network performance in areas covered by multiple wireless access networks. Today, little is known about how to effectively exploit this potential. We study a model where flows are transferred over multiple parallel networks, each of which is modeled as a processor sharing node. The goal is to minimize the expected transfer time of elastic data traffic by smartly dispatching the flows to the networks, based on partial information about the numbers of foreground and background flows in each of the nodes. In the case of full state information, the optimal policy can be derived via standard MDP-techniques, but for models with partial information an optimal solution is hard to obtain. An important requirement is that the splitting algorithm is efficient, yet simple, easy-to-implement, scalable in the number of parallel networks and robust against changes in the parameter settings. We propose a simple index rule for splitting traffic streams based on partial information, and benchmark the results against the optimal solution in the case of full state information. Extensive simulations with real networks show that this method performs extremely well under practical circumstances for a wide range of realistic parameter settings.