Gsp气化炉建模与动态模拟

为了能够更好的模拟Gsp煤气化炉,建立了新的气化炉模型。Gsp煤气化炉内部反应较为复杂,温度、压力较高难以模拟,为了对气化炉建立数学模型并且对生产工艺进行动态模拟,通过对煤气化炉装置物料流动方式的分析,结合煤气化反应的动力学、物料衡算和能量衡算,简化反应过程的次要因素,最终用通用化工动态流程模拟优化软件平台建立了气化炉反应器的串联全混流模型,并且选用四阶龙格-库塔法进行求解计算。反应器动态模拟的数值结果与实测值相比较,发现通过优化计算的结果可以把误差控制在1%以内,证明建立的数学模型能够很好地模拟工艺流程,为模拟Gsp煤气化炉提供了一种新的思路。     

三相鼓泡床反应器中固体浓度分布与数值模拟

在气、液两相为连续相固相为颗粒流(granular)的基础上进行模拟,建立了描述三相浆态鼓泡床中湍流流动的模型,在模型中考虑了气相在穿过液相中所形成的气泡直径以及固体颗粒大小对系统的影响,同时对任意两相之间的连续性方程和动量方程进行耦合。以三相浆态鼓泡床固体浓度分布为例进行数值模拟,模拟值与实验值吻合较好,表明模型可靠,模拟方法正确,为研究三相浆态床流态特征提供了一种便捷的方法,也为三相浆态床反应器的设计、开发、放大开辟了一条新的道路。     

基于Fluent的多相模拟反应器的设计

介绍Fluent在大气环境研究领域的应用,利用Fluent进行实验室多相反应的模拟反应器的数值模拟工作,以便得到最佳的反应器设计大小尺寸及反应条件,指导设计反应器。二相流采用Euler方法,湍流模型选择k-ε模型描述。设计了不同的三组模型模拟计算。并做对比,最终选择反应器设计为筛板与进气口分离,筛孔密集分布的设计方案,6个进气口均匀分布在反应器底部,4个气溶胶进口及4个压力出口在反应器顶部均匀分布。反应条件设为底部进气口进气速度0.5 m/s,气溶胶进口速度0.1 m/s.最终颗粒物在反应器内的分布从空间及时间上而言.在轴线处均大体是均匀分布,可以保证液滴捕集颗粒物模拟实验的准确性。     

基于类面向对象的模型表达与反应器模拟模型系统研究

提出了基于类面向对象的模型结构化表达方法,形成由模型框架、模型类和模型实例构成的继承层次,并应用到天然气等离子体合成乙烯乙炔反应器模拟研究中。同时考虑到模拟模型在多种条件下的优化,以星形模式设计描述模型关系。另外针对等离子体系的特点还讨论了以RGB三色素的不同合成描述温度分布的方法。最后介绍了反应器模拟模型系统的结构和功能。     

压气机三维流场数值仿真及湍流模型研究

本文利用商用CFD软件对压气机转子通流部分建立了一个三维的数值模拟计算平台.对NASA Rotor 37跨音速压气机转子全工况特性进行了计算,与NASA Rotor37的实验结果对比表明,本文的网格生成技术和数值模拟方法都是比较成功的,满足一定的数值求解精度,具有工程技术应用价值.在湍流模型方面引入Baldwin-Lonax(B-L)湍流模型和Spalart-All-maras(S-A)湍流模型,并对模拟结果进行了分析对比研究.对跨音速压气机转子内流场的数值模拟结果表明:S-A湍流模型对跨音速压气机转子的模拟能力优于B-L湍流模型.     

颗粒动力学与湍动能耦合的稠密两相流动数学模型

在气相湍流流动的k-ε模型基础上,建立了颗粒动力学与湍动能耦合的稠密两相流动数学模型。颗粒相的有效粘性系数取决于颗粒之间相互碰撞而引起的层流粘性以及颗粒微团的湍流脉动而形成的湍流粘性,其中颗粒的碰撞行为以及所形成的颗粒的层流特性用颗粒动力学模型来描述,颗粒的湍流特性采用颗粒湍动能输运方程模型来描述。利用所建立的模型对提升管内气固两相流动过程进行了数值模拟,可以合理地预报出提升管内气固两相的环核流动结构。     

聚碳酸酯合成中光化反应器的数值模拟

为了研究聚碳酸酯合成光化反应器内部的流场,了解反应器内部的混合情况,采用Fluent软件,用欧拉多相流及可实现k-ε模型,数值模拟了反应器内部的流体流动,分析了不同混合管长对物料混合的影响并得到了相应的最优管长;在最优管长下得到了反应器内部流场的速度分布、压力分布和体积分率分布,并对其流动特性进行了分析,获取了反应器内湍流流动的计算结果,为聚碳酸酯合成光化反应器的设计提供了数据。     

颗粒动力学与湍动能耦合的稠密两相流动数学模型

在气相湍流流动的κ-ε模型基础上，建立了颗粒动力学与湍动能耦合的稠密两相流动数学模型。颗粒相的有效粘性系数取决于颗粒之间相互碰撞而引起的层流粘性以及颗粒性以及颗粒微团的湍流脉动而形成的湍流粘性，其中颗粒的碰撞行为以及所形式的颗粒的层流特性用颗粒动力学模型来描述，颗粒的湍流特性采用颗粒湍动能输运方程模型来描述。利用所建立的模型对提升管内气固两相流动过程进行了数值模拟，可以合理地预报出提升管内气固两相的环核流动结构。     

湍流效应退化图像的数值模拟和仿真计算

大气湍流干扰空中目标的成像探测,使得观测到的目标图像是严重抖动和模糊的.为了具体分析湍流效应退化图像的特征,总结了光学成像系统的传输特性和湍流流场的统计特性,用随机相位屏对大气湍流效应进行了数值模拟,建立了湍流形成畸变波前过程的仿真模型,对点源目标发出的光波经过湍流流场后,在成像探测器焦面上形成的点源目标图像,计算了短曝光像和长曝光像的光强分布,定义了描述像点弥散和抖动的指标,并进行了定量分析和仿真计算.通过对计算结果进行分析,验证了仿真模型的合理性,并对湍流效应造成的图像退化给出了定量的描述,对进一步进行湍流效应退化图像校正算法研究具有重要意义.     

复杂天气下飞行HLA协同仿真系统的研究

在气动扰动影响下,笔者设计了一套数值求解大型飞机飞行的实时联合仿真模型。通过模拟实际飞行环境,用数值模拟方法研究大型飞机在低空大气湍流中的动态响应情况。应用联合仿真平台,既模拟了大气湍流,又经过数值求解计算,得出大气扰动与飞行性能响应的关系,可用来研究各类复杂大气扰动下的动力学分析与实时仿真问题。     

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.