基于US-D-DD飞机油耗区间估计

飞机油耗区间估计是航空公司系统规划和运行决策的重要依据,针对传统油耗估计中对实际业载和航程差异分散特征以及运行环境和驾驶员操作习惯等因素变化的不确定性未能充分考虑而影响整体区间估计结果的问题,提出一种基于数据偏离性和密度分布欠采样US-D-DD(under-sampling based on data deviation and density distribution)的飞机油耗区间估计方法.对于同一机型的全部航程,在考虑数据的偏离性和密度分布的同时,运用相关向量机(RVM)建立飞机油耗区间估计模型,获得一定置信水平的飞机油耗区间估计结果.依据给出的综合评估指标,将考虑数据分布特性前后的结果进行对比,实验结果表明,该方法取得了更好的区间估计效果,验证了其有效性.     

航段截尾油耗数据的区间估计方法

对航段截尾油耗数据进行区间估计时，数据分布的稀疏性及非正态性会导致传统基于单因素的油耗估计区间难以建立。针对上述问题，提出基于分类和沙普利加性解释（classification and Shapley additive explanations,C-SHAP）的改进分位数回归森林区间估计（quantile regression forest,QRF）方法。通过C-SHAP方法，筛选全航程和各飞行阶段特征得到最优输入特征集；采用随机过采样算法增加训练集中截尾油耗样本的权值，提高QRF模型的估计性能；通过QRF估计给定上、下限油耗条件分位数，构建估计区间。实验结果表明，该方法的特征选择合理、估计区间质量较高。     

小样本下基于Bootstrap的航程油耗预测方法

利用传统的数据分析方法预测飞机燃油消耗量需要大量的样本,针对这一问题,提出一种基于Bootstrap统计理论建立油耗预测模型的方法.基于真实的QAR(quick access recorder)数据,首先利用Bootstrap统计方法得到相关航程下油耗均值和一定置信水平下均值的置信区间,然后对多组均值和置信区间的上、下限分别进行拟合建模,能够得到油耗与航程关系模型及航程与燃油消耗带关系模型.最后,将结果分别与最小二乘法下的预测模型及2203组数据样本下的油耗模型作对比,结果表明:小样本量下的Bootstrap方法预测模型准确度较高.     

油耗预测中显著影响参数提取方法的仿真

在油耗预测中显著影响参数提取问题的研究中,QAR记录了大量与飞行油耗相关的真实过程参量.由于参数之间呈非线性关系,若将相关参数全部输入到模型中,将导致油耗预测模型结果复杂,运行时间长,预测精度低.针对以上不足,提出了一种粗糙集属性约简的油耗估计显著影响参数的提取方法,首先是对QAR数据进行预处理,然后进行离散化,离散化采用了信息熵连续属性的离散化算法,进一步提高了数据分析的可靠性,再通过Rough set软件得出核心属性,经实验,新方法在提取油耗显著影响因素中有效,而且在处理QAR数据中有着广阔的应用前景.     

航段油耗深度学习高质量区间预测算法

为提高给定置信水平下航段油耗区间预测结果的可靠性和稳定性,提出航段油耗深度学习高质量区间预测算法.通过对初级数据源进行按航段分类、无量纲化等预处理,提高预测结果的可靠性和算法的普适性;通过自适应相关参数、柔和化处理优化损失函数,进一步提高算法的可靠性、稳定性和普适性.训练得到的预测区间覆盖率在设定的置信水平周围,多次训...     

不平衡油耗数据的区间预测方法

对油耗数据进行区间预测时,数据的不平衡性会导致一般的区间预测方法得到的预测区间质量较低。针对上述问题,提出了基于SMOTE-XGBoost算法的区间预测模型。采用SMOTE算法增加训练集中少数类样本的数量,消除了训练集数据的不平衡性;对XGBoost算法的分位数损失函数进行改进,平滑其一阶导数原点周围的小区域,解决了分位数损失函数对树分裂的影响;通过训练区间预测模型,得到预测区间的上下界。最后基于QAR数据集进行对比实验,结果表明,该方法使预测区间具有较高的区间覆盖率和较窄的区间宽度,提高了预测区间的质量。     

基于标准欧氏距离的燃油流量缺失数据填补算法

为减小数据缺失对飞机油耗统计推断精度带来的负面影响,针对基于传统欧氏距离、马氏距离以及精简关联度的最近邻填补算法的不足,提出了一种基于标准欧氏距离的填补算法来估计QAR(Quick Access Recorder)数据中部分燃油流量数值的缺失。该算法通过QAR数据样本之间的标准欧氏距离选择最近邻样本,并利用熵值赋权法计算最近邻的加权系数,基于最近邻样本中燃油流量的加权平均即可得到缺失燃油流量的估计值。实验结果表明,标准欧氏距离能够有效度量样本相似性,所提出的算法优于常规填补算法,是处理飞机油耗数据缺失的一种有效方法。     

基于自适应无迹卡尔曼滤波QAR数据降噪研究

针对QAR数据包含离群值、噪声值等异常数据严重影响数据分析的问题,提出了一种自适应无迹卡尔曼滤波的数据降噪方法.利用改进拉依达准则剔除粗大误差数据,以无迹卡尔曼滤波为基础,结合Sage-Husa噪声估计器对系统噪声进行实时预测和修正,有效地解决了系统噪声时变的问题.利用空客A330飞机的数据样本对算法有效性进行了数值验证,仿真结果表明,自适应无迹卡尔曼滤波算法估计精度更高,降噪效果更优.研究可提高基于QAR数据分析与挖掘工作的数据质量.     

飞机燃油消耗估计模型仿真研究

针对现有燃油估计方法大多只考虑飞机纵剖面、巡航阶段且模型参数复杂等问题,传统方法工程应用较差,提出一种采用T-S模糊神经网络的飞机燃油消耗估计模型.通过提取特定航班的若干次QAR数据及飞机性能,不同航段关键影响因素,实行航路分阶段建模.仿真中前件网络参数采用改进的衰减记忆全局关联函数和学习率自适应调整相结合的梯度下降算法进行计算,后件网络采用改进的遗传算法.实验结果表明,改进方法有效的提高了估计精度,更加契合工程应用需求,具有较高的实用价值.     

改进深度信念网络在飞机下降段油耗估计中的应用

为准确估计飞机油耗量,针对飞机下降段油耗影响因素众多且与油耗呈非线性关系的特点,提出一种基于改进深度信念网络(DBN)模型的飞机下降阶段油耗估计方法。通过引入高斯-伯努利受限玻尔兹曼机(GBRBM),解决传统DBN模型中受限玻尔兹曼机(RBM)处理连续油耗输入数据时信息丢失问题;采用自适应步长(AS)策略加快收敛速度。该方法利用改进DBN模型的深层非线性网络结构实现油耗影响因素与油耗复杂非线性函数关系的逼近,并通过模型顶层连接的BP网络进行油耗估计。实验结果表明,改进DBN模型在复杂非线性估计方面有较大优势,油耗估计精度和拟合度较高,验证了该方法在飞机下降段油耗估计领域具有可行性。     

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。     

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.