声学多普勒流速剖面仪实验室测试方法探讨

用声学多普勒流速剖面仪(ADCP)进行流量测量是近几年兴起的新技术,但声学多普勒流速剖面仪如何在实验室环境中进行测试是一个难点.给出了一种声学多普勒流速剖面仪实验室测试方法,该实验室由水槽、气泡发泡装置、仪器固定支架和自动化系统构成,通过气泡发泡装置模拟自然河流悬浮颗粒和水中气泡,仪器固定支架固定仪器并旋转超声换能器使其和水流方向一致,自动化系统携带仪器前进后退形成相对流速.此方法可以比测实测流速和自动化系统行进速度,简化了国标、行标中声学多普勒流速剖面仪的检测方法以及测试条件和设备需求,大大降低了开发仪器的测试、检测成本,更有利于国内仪器的研制和推广.     

声学多普勒流速剖面评价方法介绍与探讨

声学多普勒流速剖面仪是20世纪80年代初发展起来的一种新型测流设备,目前被广泛用于流速和流量测验。介绍了美国地质调查局(简称USGS)对声学多普勒流速剖面仪的评价方法,并探讨利用国内现有流速仪检定水槽评价多普勒流速剖面仪的方法。通过USGS的大量实践和我国水文工作者的工作,通过设备比测、底跟踪基线比测、断面流量比测、检定水槽等方法可有效评价声学多普勒流速剖面仪的流速性能。     

声学多普勒流速仪计量检定工作分析

从水量准确计量为切入点,根据声学多普勒流速仪推广使用中存在的计量检定问题,结合水利水文专业计量体系的促进和发展,论证了声学多普勒流速仪计量检定工作开展的必要性。从声学多普勒流速仪工作原理出发,探讨了利用水槽检定该类仪器的原理和方法,分析了检定方法的可行性。研究说明,利用现有水槽检定还存在一定难点,如何利用现有水槽,还需要进行试验。     

平原区河道流速分布规律及其在横向声学多普勒流量测验系统中的应用

横向声学多普勒流速仪(H-ADCP)因其测验的自动高效和信息传输的快捷在流量测验中得到广泛应用。针对现状代表流速选取存在水文物理含义不明的缺点,根据垂线流速分布理论模型,并结合实测垂线流速资料,提出了平原区不同类型河道流速分布拟合模型,并实际引用。应用结果表明：基于幂指数函数和一元多项式函数拟合的流速分布模型能够用于H-ADCP层流速到垂线流速的转化,率定的单断关系精度可靠,可为H-ADCP测流系统流速率定单断关系提供新的方法。     

基于声学多普勒流速仪测流的断面流速分布研究

选择泾河、射阳河闸2个水文站的走航式声学多普勒流速仪测流数据,进行测流断面上的垂向、水平层流速分布及垂向平均流速的横向分布研究。研究结果表明:对于顺直河段,垂线点流速分布基本符合理论流速分布;对于受感潮影响的测流断面,相对流速脉动和均化影响较大,难以找到流速分布规律。通过基于断面流速分布特点的断面有效测速单元确定,可以为测速垂线和垂线上测速点的布设、固定式声学多普勒流速仪安装位置选择等提供技术支撑。     

语音声学参数自动标注/提取系统简介

该文重点介绍了一个实用的语音声学参数自动标注/提取软件系统。使用该系统能够极大地降低语音参数标注和采集的错误率,有效提高语音声学参数库研制效率,确保实验方法和实验数据的可重复性和可验证性,从而推动语音声学参数数据库研制和语音声学实验研究工作的规范化和标准化。     

流速分布规律在横向声学多普勒流量测验系统中的应用

横向声学多普勒剖面流速仪(H-ADCP)因其测验的自动高效和信息传输的快捷在流量测验中得到广泛应用。针对现状代表流速选取存在水文物理含义不明的缺点,根据垂线流速分布理论模型,结合实测垂线流速资料,提出平原区不同类型河道指数、一元多项式流速分布模型,并实际应用于百渎口站 H-ADCP 测验系统的单断关系率定。应用结果表明：基于指数流速的分布模型能够用于 H-ADCP 层流速到垂线流速的转化,率定的单断关系精度可靠,为 H-ADCP 测流系统流速率定单断关系提供新的方法。     

智控扫描式声学多普勒测流系统应用探讨

为加快水文监测新技术与装备在水文测报中的应用,在浙江嵊州站、江苏前垾村水文站分别建设智控扫描式声学多普勒流速仪测流系统示范应用站点。智控扫描式声学多普勒流速仪测流系统,通过水下智控转动扫描测流方式使传统的一维流速剖面数据扩展为二维扫描流速数据,并融合计算流体动力学、人工智能等多学科前沿技术,建模仿真河道流场以计算实时流量,原理上可有效提高测流精度和降低人工比测率定分析的工作量。通过对示范应用站点半年时间运行的稳定性和流量监测数据比测分析,得出示范应用站点测流系统稳定可靠,流量监测和人工监测数据趋势基本一致;在流态快速变化期间,测流结果存在一定迟滞性,可采用提升扫描速度的方式提高对流速变化的敏感度;流体及神经网络算法模型还需要进一步优化,结合多模型算法提高智控扫描测流系统的智能化能力,进一步提高流量监测的精度。     

基于FPGA声学多普勒流速剖面仪的信号处理机设计

针对声学多普勒流速剖面仪的高速信号采集和处理对运算实时性与易升级的需求,提出一种基于现场可编程门阵列(FPGA)的软硬件协同设计方法。阐述声学多普勒剖面仪的测流原理,选择FPGA作为单一的信号处理器,使用Verilog HDL语言描述易于用硬件实现的模块,如同步采集、低通滤波及复数相关运算等计算量大的模块。采用FPGA内部的MicroBlaze软核作为系统的中央处理器,进行流程控制、分支判断以及调用硬件模块来控制系统回波信号的采集、处理和存储。实验结果表明,FPGA信号处理的实时性满足系统要求,且具有较高的精确性。     

点式超声波流速仪设计

点式超声波流速仪根据超声相位偏移测量原理设计而成。其核心是装在壳体内的单片机测控系统，能实时、连续、自动测量及显示特定测点的流速和流向。由于采用了声速补偿方法，保证了测量精度。     

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.     

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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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