管制空域内无人机与有人机侧向碰撞风险研究

随着无人机的逐渐发展和使用范围的扩大,空域将变得越来越拥挤。把无人机系统融入有人机管制空域将是未来解决空域拥挤问题的必要手段之一。基于无人机性能特征和机载设备设施要求,结合有人机和无人机的延迟推导出二者之间的管制防撞间隔,并根据等效安全水平原则求出二者之间可行的目标安全水平。在Reich模型的基础上进行改进,从而建立有人机与无人机的侧向碰撞风险模型,再通过仿真算例对不同管制空域内的有人机和无人机之间进行风险评估,计算碰撞风险并与目标安全水平进行比较。仿真结果表明在1000 m以上的管制空域采用所推导的防碰撞间隔满足ICAO规定的碰撞风险要求,所以该间隔可以作为无人机融入有人机管制空域时的侧向间隔使用。     

基于稀有事件仿真的商业银行IT操作风险评估研究

系统仿真是风险评价的一种重要手段,针对商业银行IT操作风险预警问题,提出了一种基于稀有事件仿真的IT操作风险评估方法。采用商业银行IT操作风险的概率作为衡量IT操作风险高低的标准,构造基于稀有事件的商业银行IT操作风险识别模型,利用交叉熵方法构建了一种稀有事件仿真的有效算法,并由此估计出发生损失的概率。实证分析结果表明,模型对商业银行IT操作风险具有很强的识别能力,从而提供了一个风险预警的新视角。     

基于概率统计的空域容量评估模型研究

利用概率统计的方法分析研究空域容量的评估问题,从理论上建立估计空域容量的数学模型与方法,建模过程考虑了飞行规则、管制员的能力,空管有关间隔规定,以及机型混杂等多种因素的影响,可分别计算航路、交叉点及空域的容量.在该模型的基础上,设计开发空域容量评估系统,对空域的理论容量进行评估,并利用该系统对某空域容量进行了计算,实际数据证明该模型具有一定的可行性.     

基于稀有事件仿真的商业银行个人信用风险评估研究

系统仿真是风险评价的一种重要手段,针对商业银行个人信用风险预警问题,提出一种基于稀有事件仿真的个人信用风险评估方法.采用商业银行个人未偿还贷款的概率作为衡量个人信用风险高低的标准,构造基于稀有事件的商业银行个人信用风险识别模型,利用交叉熵方法构建了一种稀有事件仿真的有效算法,并由此估计出发生损失的概率.实证分析结果表明,模型对商业银行个人信用风险具有很强的识别能力,从而提供了一个风险预警的新视角.     

IEEE802.11e无线局域网语音性能分析模型

无线多媒体传输中,正确评估IEEE802.11e无线局域网的语音质量尤为重要.提出一种IEEE802.11e无线局域网的语音质量评价模型.该模型引入E-Model VoIP语音质量评估方法,估计IEEE802.11e无线局域网的语音质量.重点考虑碰撞丢失对语音质量的影响,建立新的碰撞概率表达式.通过MATLAB、NS2仿真分析比较了不同碰撞概率在新模型下的语音质量.结果表明提出的碰撞概率在新模型下语音质量最接近真实值,具有最高的评估准确度.     

交叉熵算法在企业违约风险评估中的应用研究

系统仿真是风险评价的一种重要手段,针对企业违约预测问题,提出了一种基于交叉熵算法的违约风险评判方法。采用公司未偿还贷款的概率作为衡量违约风险高低的标准,利用交叉熵方法构造企业违约风险识别模型及其算法,并由此估计出发生损失的概率。与传统的预测方法进行比较,结果表明该模型对违约风险具有很强的识别能力,预测精度高。     

基于改进分水岭算法的空域实时流量监测

为缓解空中交通拥挤和拥堵现状,提高空域资源利用效率和航空器运行效率,需对空域流量进行实时监测与告警,在已有研究基础上提出改进分水岭算法的空域流量监测模型。首先对分水岭算法中的距离操作算子进行改进,其次结合航路航线与尾流间隔要求进行约束条件构建;最后选取西南贵州地区某一空域进行算法仿真,并对改进前后的空域流量监测结果进行分析说明,实验结果表明：基于传统分水岭算法的空域流量监测准确率为93.5%,改进后的监测准确率为100%,证明改进分水岭算法在空域流量监测方面是合理高效的。     

基于ADSB的RVSM空域模拟监视系统研究

广播式自动相关监视系统(ADSB)现已成功应用于无雷达覆盖地区和高密度飞行区域的远程航空器运行监视,可以用作缩小垂直间隔(RVSM)空域航空器高度保持性能监视.本模拟监视系统的研究结合了广汉机场的ADSB运行实际,逼真地模拟了飞机目标的运动,实现了飞机的高度、航向、速度等参数改变的实时便捷操作,解决了飞机自动加入修正角航线等几个关键飞行程序的模拟,为RVSM空域内安全监视及进行航空器高度保持性能监视的完成奠定了基础.     

ADS-B信息的球状模型飞行冲突探测算法

随着空中飞行流量日趋增大,飞行器自由飞行过程中发生碰撞的可能性也越来越大,针对飞行器周围空域进行合理划分,给出了一种基于ADS-B信息的球状模型飞行冲突探测算法.该算法结合ADS-B的原理和特点,运用球状模型取代圆柱体模型对飞行器周围空域进行建模,然后进行冲突目标初选,对可能发生冲突飞行器的位置、航迹交叉点、距离进行计算并预估到达时间,与门限值比较判断能否发生碰撞,最后,对算法进行仿真.结果验证:算法能够更准确并且快速地完成冲突探测,并对驾驶员发出冲突告警,对防止飞行冲突的发生具有积极作用.     

基于改进贝叶斯模型的信息安全风险评估

 随着信息化时代的到来,信息安全问题变得日益复杂与多样,因此急需一种高性能的解决方法。本文在前人的研究基础上进一步改进贝叶斯网络模型在信息安全风险评估中的应用。首先分析信息系统风险元素种类,提出一种新的确定风险因素的方法,即建立因素之间常见关联关系;然后依据因素关联关系确定信息系统指标体系,并结合经验积累的条件概率,利用Matlab贝叶斯网络工具箱（BNT）构建完整的贝叶斯网络风险评估模型,其中包括对评估流程、方法使用及风险等级确定的分析;最后通过实例分析改进的贝叶斯评估模型,对实验数据推理出风险各等级概率。仿真结果与实际结论相一致,表明改进的贝叶斯评估模型能够准确反映信息系统安全风险等级,是一种有效且合理的评估方法。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

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。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

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。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。