人群行为分析研究综述

近年来,人群行为分析成为计算机视觉领域中备受关注的研究方向,主要运用于智能视频监控、人机交互、智能家居、视频检索等领域,以视频中运动人群的行为分析和理解为研究目的,对输入序列图像中的运动目标进行运动检测、匹配和建模.文中对人群行为分析的研究现状以及典型算法进行全面综述.首先对当前人群行为数据库进行简要介绍并分类比较;之后根据人群行为分析算法核心侧重点的不同,将人群行为分析算法分为基于特征和基于模型两大类,并根据每一大类各自的特点进行细分和比较,详细介绍了每类中具有代表性的算法,分析各算法的优缺点和适用的人群场景;最后总结了人群行为分析中的困难和挑战,对该研究领域的发展进行展望.     

城市轨道交通智能视频分析关键技术综述

轨道交通是改善城市公共交通状况的有效途径。随着城市轨道交通的快速建设,人们对城市轨道交通的安全问题越来越重视。智能视频分析技术通过对监控视频流的实时分析,对场景中的各种目标进行检测、分类、跟踪,并分析和判断目标的行为,从而能在异常情况发生时可以及时报警、主动防范,提高处理突发事件的效率。主要研究了智能视频分析技术在轨道交通智能视频监控系统中的应用背景及技术框架,总结了智能视频分析中的关键技术的不同实现方法及其常见的算法。     

智能视频监控系统异常行为检测算法研究综述

随着公共安全需求的快速增长,监控摄像头数量不断增多,视频监控数据呈爆炸式增长;传统的视频监控系统难以对如此海量的数据进行理解分析,因此智能视频监控系统应运而生;作为一个跨学科的研究领域,智能视频监控系统异常行为检测技术迎来重大机遇的同时也面临不少挑战;为了更好地研究智能视频监控系统异常行为检测算法,梳理了相关研究并从原理上对不同算法进行分类,对基于能量、基于聚类、基于重构、基于推断以及基于深度学习几个不同依据的算法进行对比分析,归纳了各类算法的分支研究方向,接着简要介绍了异常行为检测常用的公开数据集,最后讨论了目前异常行为检测算法所面临的挑战并针对性地提出了未来智能视频监控系统异常行为检测算法的可行研究方向。     

视频中运动目标分类方法研究

现如今智能视频监控是计算机的一项热点应用,发展前景十分广阔,通过计算机的作用,可将目标从监视图像中提取出来,以此来实现分类处理.本文根据以往工作经验,对智能视频监控技术的方法流程进行总结,并从静态特征的运动目标分类、运动特征的运动目标分类、动静结合的运动目标分类三方面,论述了视频中运动目标分类的研究方法.     

智能视觉监控技术研究进展

新一代智能视觉监控技术的研究是一个极具挑战性的前沿课题,它旨在赋予监控系统观察分析场景内容的能力,实现监控的自动化和智能化,因而具有巨大的应用潜力。视觉监控系统的智能化分析过程由运动目标检测、分类、跟踪和视频内容分析等几个基本环节组成,其中视频内容分析又包括异常检测、人的身份识别以及视频内容理解描述等。本文在总结以上有关关键技术研究进展的基础上,进一步提出将超分辨率复原技术引入视觉监控领域,介绍了超分辨率复原的主要算法及其在智能视觉监控中的应用。     

人脸识别视频分析的设计与实现

智能视频监控随着大数据视频分析技术的应用得到迅速发展,通过实时监控,视频分析系统即时反应。识别出视频监控采集到的目标人脸。在基于ARM11的S3C6410嵌入式硬件平台,以Linux操作系统为软件平台,用LBP算法对人脸图像进行预处理,减少光照对识别的干扰;用PCA算法对经一致模式统计后的均衡直方图进行特征提取和降维,降低数据的计算量;对降维后的数据运用岭回归算法进行分类,设计并优化LBP＋PCA算法,结合RidgeRegression分类技术作为人脸识别视频分析的解决方案。     

关于智能视频监控中运动目标的分类识别研究

智能视频监控是计算机视觉中视频分析技术的一个重要应用方向,在各个领域中得到了广泛的应用,并取得了良好的成绩.对此,本文提出了一种监控视频中运动目标识别分类法,并通过对视频监控运动目标的提取来获得Zernike矩高阶矩、长宽比和占空比,之后再运用向量机进行分类识别,并证所得出来的分类识别结果具有较高的准确性.     

视觉单目标跟踪算法综述

目标跟踪技术根据视频上下文信息，建立一个跟踪模型对目标的运动状态进行预测，被广泛用于智能视频监控、自动驾驶、机器人导航、人机交互等多个计算机视觉领域。随着深度学习在语音识别，图像分类以及目标检测等领域的巨大成功，越来越多的研究将深度学习框架应用于目标跟踪任务中。介绍了当前单目标跟踪任务的难点和传统的方法,重点分析了当前基于深度学习的单目标跟踪算法的发展现状，从预训练网络＋相关滤波算法、基于孪生网络的方法、基于卷积神经网络的方法、基于生成对抗网络的方法以及其他深度学习方法几个方面，分别对当前流行的深度学习目标跟踪算法进行了概述。此外，总结了用于评测单目标跟踪算法性能的代表性数据集，列举了最新的研究成果在不同数据集上的实验结果并分析了当前单目标跟踪领域的问题和趋势。     

基于深度学习的视觉单目标跟踪综述

单目标跟踪是一种在视频中利用目标外观和上下文信息对单个目标分析运动状态、提供定位的技术,在智能监控、智能交互、导航制导等方面具有应用前景,但遮挡、背景干扰、目标变化等问题导致实际应用的进展缓慢.随着近年来深度学习的快速发展,研究使用深度学习技术优化单目标跟踪算法已成为计算机视觉领域的热点之一.围绕基于深度学习的单目标跟踪算法,在分析了单目标跟踪的基本原理基础上,从相关滤波、孪生网络、元学习、注意力、循环神经网络和生成对抗网络六个方面,根据核心算法的不同分别进行了概述和分析;此外,对研究现状进行了总结,提出了算法的发展趋势和优化思路.     

基于计算机视觉的行人检测技术的发展

智能车辆作为智能交通系统的关键技术,是许多高新技术综合集成的载体。智能车辆的一个非常重要的研究课题就是在城市道路交通环境下如何避免行人被车辆碰撞。总结了基于计算机视觉的行人检测的现有的主要技术,针对摄像机在交通视频监控系统中的静止情况,以及在智能车辆上的运动情况下的行人检测算法及其性能进行了评述和比较,并分析了当前行人检测技术的研究现状,指出了存在的问题和研究前景。     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).