基于人群活力的北京市延庆区城市公园风环境评价

[目的]已有风环境研究多从单一条件对城市空间风环境进行评价并提出优化策略,忽略了人群有效活动空间的影响,以简化体块代替公园物理环境部分要素,一定程度影响了风环境模拟分析结果的准确性。[方法]以占北京市风力资源70%的延庆区4个典型城市公园为对象,从公园人群游憩活力视角,结合场景建模技术、通讯探针和人工智能识别技术,确定公园游客活动范围,以此作为公园风环境评价的研究区域;利用不同季节风速、风压和涡旋分布等评价要素量化评价公园风环境质量,并以公园风环境质量综合评价来表征公园现状风环境质量优劣程度;以公园风环境质量评分方式相关性评价来表征公园进行风环境适应性改造的难易程度。[结果]结果表明：百泉公园现状风环境质量最差,且评分随季节变化呈现出明显差异性和不规律性;集贤城市森林公园风环境质量评分随季节变化有规律地逐渐减小,且进行风环境适应性改造难度最小。[结论]研究建立了全面的公园风环境质量评价体系,对延庆区城市公园建设和管理具有应用价值,为华北地区城市公园风环境质量评价提供创新方法。     

填石挤淤及强夯法在盐渍湖软土路基处理中的应用

某盐渍湖软土路基公路工程采用填石挤淤和强夯施工技术对软土路基进行了处理.在施工过程中,通过采用平板载荷检测,来评估地基承载力能否达到设计要求,并通过钻探和重型动力触探试验对处理后的路基进行了检测.结果表明,其处理效果能满足设计和工程质量要求.     

Agent-CA的体育场馆人群疏散模型

根据体育场馆人群疏散的特点与规律,提出一种基于多智能体和元胞自动机相融合的大型体育场馆人群疏散模型（Agent-CA）。将元胞空间中被虚拟人个体占据的元胞视为一个独立的智能体,将元胞及其状态进行封装,扩展为具有自主性的智能体,通过设计各种人群疏散行为策略做为演化规则,实现个体的差异性以体现个人个性、体力、心理等对疏散行为的影响,对体育场馆的人群疏散进行仿真实验。结果表明,Agent-CA综合了多智能体和元胞自动机的优点,充分考虑了个体内在因素,更接近现实大型体育场馆的人群疏散情形,缩短了疏散时间。     

大规模虚拟民众群体行为仿真概念建模研究

针对现实社会中大规模社会民众群体所具有的复杂性特征,将复杂网络最新研究成果与基于Agent的成熟建模理念相结合,提出了一个虚拟战争空间中大规模社会群体行为建模的概念建模框架,该框架由三部分组成：Agent 、关系网络、智能环境（Agent Relation Environment,ARE）,给出了该框架所涉及的一系列概念的定义,对框架的内容和特点进行了较为详细的阐释和探讨。     

基于GPU的视频流人群实时计数

为了解决人群遮挡严重、光照突变等恶劣环境下人群计数准确率低的问题,提出基于混合高斯模型（GMM）和尺度不变特征变换（SIFT）特征的人群数量统计分析新方法。首先,基于GMM提取运动人群,并采用灰度共生矩阵（GLCM）和形态学方法去除背景中移动的小物体和较密集的噪声等非人群前景,针对GMM算法提出了一种效率较高的并行模型;接着,检测运动人群的SIFT特征点作为人群统计的基础,基于二值图像的特征提取大大减少了执行时间;最后,提出基于人群特征数和人群数量进行统计分析的新方法,选择不同等级的人群数量的数据集分别进行训练,统计得出平均单个特征点数,并对不同密度的行人进行计数实验。算法采用基于GPU多流处理器进行加速,并针对所提算法在统一计算设备架构（CUDA）流上任务的有效调度的方法进行分析。实验结果显示,相比单流提速31.5%,相比CPU提速71.8%。     

改进遗传算法在人群行为仿真中的应用

针对目前人群行为仿真中多目标,有约束的组合优化问题,提出了一种改进遗传算法在人群行为仿真的应用方案。通过设定特殊的数据结构、仿真过程中的各种约束规则、遗传算法中的基因编码、适应度评价函数实现了人群行为仿真。仿真实验验证了该算法可以大大减少搜索空间,并能使结果达到最优。     

Towards a quantitative approach for comparing crowds

In this paper, we propose a new model to quantitatively compare global flow characteristics of two crowds. The proposed approach explores a 4‐D histogram that contains information on the local velocity (speed and orientation) of each spatial position, and the comparison is made using histogram distances. The 4‐D histogram also allows the comparison of specific characteristics, such as distribution of orientations only, speed only, relative spatial occupancy only, and combinations of such features. Experimental results indicate that the proposed quantitative metric correlates with visual inspection. Copyright © 2012 John Wiley & Sons, Ltd.     

Politeness improves interactivity in dense crowds

Traversing dense crowds can be challenging, but it is especially difficult in a virtual environment where the user is limited to simple input devices. Predicting near‐future user movements with a hidden Markov model allows nearby autonomous agents to react politely, that is, to specifically avoid impeding the movement of the user. This predictive model and simple avoidance scheme are tested by six subjects in 360 short interactive games and by a 10‐participant two‐alternative forced choice questionnaire. Polite agents are found to significantly improve the player's ability to navigate quickly and without collision, and the resulting character movements showed increased naturalness for two of the three game scenarios. Copyright © 2012 John Wiley & Sons, Ltd.     

Efficient rendering of animated characters through optimized per‐joint impostors

In this paper, we present a new impostor‐based representation for 3D animated characters supporting real‐time rendering of thousands of agents. We maximize rendering performance by using a collection of pre‐computed impostors sampled from a discrete set of view directions. Our approach differs from previous work on view‐dependent impostors in that we use per‐joint rather than per‐character impostors. Our characters are animated by applying the joint rotations directly to the impostors, instead of choosing a single impostor for the whole character from a set of pre‐defined poses. This offers more flexibility in terms of animation clips, as our representation supports any arbitrary pose, and thus, the agent behavior is not constrained to a small collection of pre‐defined clips. Because our impostors are intended to be valid for any pose, a key issue is to define a proper boundary for each impostor to minimize image artifacts while animating the agents. We pose this problem as a variational optimization problem and provide an efficient algorithm for computing a discrete solution as a pre‐process. To the best of our knowledge, this is the first time a crowd rendering algorithm encompassing image‐based performance, small graphics processing unit footprint, and animation independence is proposed. Copyright © 2012 John Wiley & Sons, Ltd.     

基于贝叶斯模型的相机间人群目标识别

准确获取相互遮挡粘连目标的位置特征,是在视野有重叠区域条件下进行相机间目标识别的关键。提出首先构造人体模型,利用贝叶斯模型将粘连目标的分割问题转换为求解最大后验概率问题,然后依据获得的目标轴线特征,在不同的相机间按照最小距离原则进行相同目标的匹配识别。结果表明,利用人体模型进行人群分割的抗干扰能力强,目标识别的准确率较高。