武汉城市住宅小区风环境计算机模拟分析

随着中国城市化快速增长,住宅小区风环境越发得到人们重视。对于夏热 冬冷的武汉市,城市住宅小区冬季防风以及夏季自然通风显得尤其重要。通过Airpak3.0 软 件建立武汉未建小区模型,采用  湍流物理模型求解住宅小区内风速及风压方法来研究 建筑布局与风场的关系。研究表明,计算机数值模拟能准确模拟小区风流场,建筑布局和风 向角对小区风环境影响较大。采用数值模拟方法,结合城市风玫瑰图进行合理建筑规划布局, 可为武汉住宅小区建筑布局规划建设提供指导和优化。     

掘进巷道热环境影响因素重要性分析

目前大多数研究仅讨论了单一因素对掘进巷道热环境的影响,未涉及多因素对掘进巷道热环境影响的重要性。利用Fluent软件对掘进巷道进行三维建模与数值模拟,通过正交试验与控制变量法分析了入风风速、入风温度、围岩温度和风筒直径对掘进巷道热环境的影响程度。数值模拟结果表明:对掘进巷道热环境的影响程度由大到小依次为围岩温度、风筒直径、入风温度、入风风速;入风风速、入风温度和风筒直径对掘进巷道热环境的影响程度保持稳定;距离掘进工作面越远,围岩温度对掘进巷道热环境的影响越显著;掘进巷道温度与入风风速之间呈负幂函数关系,增大入风风速可降低掘进巷道温度,但入风风速过大,降温效果越来越不明显;掘进巷道温度与入风温度、围岩温度之间呈线性正相关关系,与风筒直径之间呈线性负相关关系。利用Origin对数值模拟结果进行拟合,得到掘进巷道温度与入风风速、入风温度、围岩温度、风筒直径之间的多元线性回归方程,拟合程度较好,可为工程预测掘进巷道温度提供有效参考。     

双叶片直线翼垂直轴风力发电机流场特性分析

针对双叶片直线翼垂直轴风力发电机的流场复杂多变的问题,采用k-ω(SST)湍流模型进行数值模拟,展开了对垂直轴风力发电机流场特性的分析,建立了风速与位置的关系,得到了风速最低位置以及风速恢复区域.研究结果表明,三维CFD仿真所得数据与风洞试验数据虽然有所偏差但对于研究垂直轴风力发电机的流场特性影响较小;通过对垂直于z轴截面和垂直于x轴截面的风速云图分析得出:低风速区域不关于x轴对称,其偏向于y轴负半轴;利用风速值曲线定量得出随着x/R的增大,低风速区的面积逐渐扩散,其值先减小后增大.这为建立垂直轴风力发电厂建立基础.     

风对阵列定向精度影响的数值仿真研究

为研究传声系统的精度问题,针对由风导致的被动声阵列定向误差进行分析。对每一风速条件下的声场模型,采用平面四元十字阵和广义时延估计算法对声源进行全方位定向,绘制不同风速条件下的误差曲线。通过数值仿真验证,采用COMSOL Multiphysics 3.5软件,仿真了大型轮式车在不同风速条件下的二维声场。同时论证了仿真误差曲线集中体现了由风导致的误差,并指出造成误差的直接原因是风导致的声音传播方向的偏移。结果显示仿真误差曲线和理论误差曲线基本吻合,可以作为被动声阵列定向结果的矫正参考。     

考虑人体散热的轿车座舱内流场数值仿真研究

研究提高轿车热舒适性,汽车座舱空气的对流和人员体温,都会影响舒适度,有必要在开发前期,用数值方法对轿车座舱内流场进行仿真.根据雷诺平均的方法,应用RNGc-E湍流模型,为了控制舱内舒适性能,采用分区域划分网格的方法,对座舱内空气三维流场和温度场进行了数值仿真研究.引入人体模型,考虑车内人体散热对座舱内环境的影响,建立了轿车座舱舒适性研究的模型.给出了座舱内不同位置的速度分布和温度云图,分析了空调给风角度、空调给风口位置以及空调回风口位置对座舱内气流组织及温度场的影响.结果表明,采用前-中给风的给风口布置和后回风形式以及上攻角的给风口设计,均可以提高轿车座舱内乘员的热舒适性.     

基于GPS、磁罗盘与大气数据计算机的无人机风估计

针对无人机实时航路规划及适应环境变化的自主能力发展需求,提出了一种新的风估计与空速校准的方法;该方法基于GPS接收机、大气计算机和磁罗盘等传感器实现;针对定常风模型,风速、风向能够利用地速、风速和空速之间的速度矢量三角形关系计算得到;采用无导扩展卡尔曼滤波(DEKF),估计风场信息以及真空速的比例校准系数;利用某型无人机数字仿真平台,在2D定常风条件下进行了全过程自主飞行仿真;仿真结果表明:该方法在航路跟随的直线段、转弯段均能准确估计。     

一种矿用皮托管式风速传感器设计

针对传统风速传感器因井下特殊环境常造成超声波探头性能减弱,不能正确反映环境风速值的问题,提出一种矿用皮托管式风速传感器设计方案,详细介绍了其原理及软硬件设计。该传感器采用S型皮托管测量风的压力,利用差压芯片计算差压信号值,并根据电信号、差压信号、风速之间的对应关系求取风速信息。实验结果表明,在0.4～15m/s风速范围内,该传感器测量误差低于±0.2m/s,且具有较好的温度稳定特性、贮存特性和防潮防堵性能。     

风载荷对车载平台稳定性干扰的研究

研究车载平台稳定性优化设计问题,针对车载光电跟踪设备工作环境的复杂性,存在温差、风载荷等外界因素干扰车载平台定位的稳定性.为了分析风载荷对车载平台重复定位稳定性的干扰程度,在车载平台的前支撑腿和后支撑腿处分别建立了数学模型,推算出在风载荷的作用下副车架的挠度公式.使用三维仿真软件MSC.PATRAN生成有限元模型,在三点支撑的状态下对模型进行变形仿真,得到0级、4级、5级、6级风速下的副车架的变形值,综合比较无风状态和不同风速下的副车架变形情况,检验风载荷对车载平台稳定性的干扰情况.实验结果表明,6级风对已对准光路造成了0.3″的误差影响,与20″的工作精度要求相比,承受性能较好.验证了车载光电跟踪设备可以达到6级风环境中的工作性能.     

超高速电梯气压控制系统的风口布局优化分析

超高速电梯在运行过程中,轿厢内气压的快速变化会对乘客的耳朵产生压耳感.为了减轻这种压耳感,有些超高速电梯内配备了气压控制系统,能够使电梯轿厢内的气压在运行过程中呈线性地变化,从而降低气压变化率,改善乘客的压耳感.但那些气压控制系统的风口布局方式会对乘客产生不舒适的吹风感.为了解决上述问题,提出了一种新的风口布局方式.为了验证其合理性,运用计算流体力学分析软件Fluent对气压控制过程中的增减压过程进行了数值仿真,并对不同送排风口的设置以及在不同的风口高度下,电梯轿厢内的风速场进行分析.仿真结果表明,采用非对称的风口布局方式在人体头部周围产生的风速较小,是一种较优的风口布局方式.     

基于Fluent的超声波换能器测风阵列模型改进研究

针对垂直相交型阵列易受阴影效应影响的问题,根据时差法原理,采用三组超声波换能器互成120°放置,设计了一种具有三条独立测风路径的改进型测风阵列,并建立了风速计算模型。该阵列保证至少有两组换能器正常工作的前提下,对某一条受到绕流干扰严重的测风路径进行校正。利用SpaceClaim软件建立测风阵列及风洞模型,通过Meshing软件进行网格划分,使用FLUENT软件改变模拟风洞内的风速及雷诺数等指标,仿真两种阵列在不同流态下的性能表现,得到速度分布云图以及测风路径速度曲线图,说明了改进型测风阵列能明显提升测风精度。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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