共查询到20条相似文献,搜索用时 15 毫秒
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随着政府部门对家电效率及节约能源的要求,基于DSP的电机控制器逐渐进入家电领域.本文阐述了嵌入式DSP的基本特征和优势,并且就基于DSP的异步电机磁场定向控制和无刷直流电机的扩展卡尔曼滤波算法进行了讨论. 相似文献
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现场总线将成为21世纪自控技术的主流。文章对现场总线、以及作者参与分析、研究的FF基金会现场总线协议作了简略的介绍。同时把FF的相关名词术语推介给读者,以便熟悉、研究、采用该协议。 相似文献
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现场总线和现场总线控制技术 总被引:4,自引:0,他引:4
现场总线是用于现场仪表和控制室系统之间的一种全数字化、双向、多站的通信系统,是过程控制技术,自动化仪表技术,计算机网络技术三大技术发展的交汇点,这种技术必将带来控制系统的一大变革。 相似文献
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The wireless medium may cause substantial packet losses, rendering Transmission Control Protocol (TCP) inefficient. We propose a cross-layer solution by combining link-layer retransmission techniques and a solution for TCP packet reordering. It is costly to conduct link-layer retransmission with the constraint of orderly packet delivery. We require the link layer to provide reliable packet delivery, but without orderly delivery guarantee, thus transforming the problem of high packet error rates to the problem of packet reordering. The latter is dealt with by enhancing TCP with a solution for packet reordering. We justify our design by analyzing both general scenarios and the case of IEEE 802.11n. Our simulation results demonstrate that the proposed method is effective in improving TCP connection goodput in wireless networks. 相似文献
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E.v. Collani 《Microelectronics Reliability》1989,29(3)
In this paper a general approach to optimal process control is developed, which leads to relatively simple objective functions for optimization. These two features “generality” and “simplicity” are the foundation of the development of powerful approximation techniques which allow simple determination of approximately optimal solutions for a great number of cases. 相似文献
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里程碑
蓝牙(Bluetooth)市场近年以惊人的速度成长,每周出货量约1000万件,每天约有3种产品通过认证。2005年底,超过5亿个产品已配备Bluetooth解决方案。 相似文献
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在工业控制中,可编程控制器(PLC)作为工业控制装置已得到广泛的应用。采用高度实时性、高可靠性的PLC通信技术,就成为构成性能优异的自动控制系统的关键所在。Modbus协议是应用于电子控制器的一种通用语言。通过此协议,可实现控制器与其他设备(上位机)之间的远程通信。本设计就是以实验室现有的PLC为对象,实现基于Modbus协议的上位机对PLC的远程控制。实现上位机对PLC的远程控制,最理想的通信媒介就是通常所用的网线,即非屏蔽双绞线(UTP)。这就需要建立在以太网之上,即TCP/IP协议之上的Modbus通信协议。本次设计主要完成了完成了硬件连接及梯形图程序的编写,实现了控制器对输出线圈的控制,在建立PLC与上位机网络通信时,完成了对PLC通信模块的配置和PC机与PLC基于以太网的连接,采用Modbus TCP调试软件进行通信测试,测试结果表明上位机与台达PLC两个从站均可建立稳定的Modbus通信。 相似文献
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参照ITU T建议草案:吉比特无源光网络传输汇聚层规范(G.GPON.gtc),提出了一种支持分组业务接入的媒质接入控制(MAC)协议.通过仿真建模对该协议的性能进行了分析. 相似文献
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《IEE Review》2001,47(4):31-34
The offshore industry's ultra-cautious approach to fieldbus technology is beginning to change. In this paper, the author reports on the factors helping to transform automation technology in a crucial international industry 相似文献
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TCP拥塞控制研究综述 总被引:3,自引:0,他引:3
系统深入地研究了TCP协议中的拥塞控制机制,TCP改进协议中研究最多的就是对TCP拥塞窗口调节机制的改进.从这个方面来看主要可以分为三种改进类型,即基于分组丢弃反馈的拥塞窗口调节方式;基于路径延时反馈的拥塞窗口调节方式;基于显式反馈和带宽测量的拥塞窗口调节方式.另外还针对无线网络的固有特性讨论了无线网络上TCP协议的一些改进方案.深入地分析了一些典型的算法,对它们的优劣做了详细的分析和总结,并提出了今后的一些研究方向. 相似文献
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里程碑蓝牙(Bluetooth)市场近年以惊人的速度成长,每周出货量约1000万件,每天约有3种产品通过认证。2005年底,超过5亿个产品已配备Bluetooth解决方案。Bluetooth技术快速广布于各类装置的主要原因,包括低成本、低耗电量及使用方便。耳机、免持听筒、笔记本计算机、移动电话及打 相似文献
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《Communications Magazine, IEEE》2008,46(10):140-146
The latest advances in traffic measurement, analysis, and modeling play an important role in automatically building and maintaining a distributed intelligent monitoring layer that we describe as the awareness plane. The purpose of this article is to describe the components of this awareness plane in the areas of flexible network measurement, application and relationship discovery, and traffic classification, as well as data aggregation and semantically enriched infrastructure models. We present management services and scenarios, and list the research challenges on the path to integrating the components and making them interoperate for future autonomic service and network management approaches. 相似文献
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In this article we present a comprehensive survey on the architecture, protocol issues, and standard of the hybrid fiber coaxial (HFC) networks which are evolving from the existing residential CATV networks. We first describe the HFC architecture and discuss the problems in providing two-way communication. Then, we identify three important medium access control (MAC) issues in designing the IEEE 802.14 standard; namely, synchronization, upstream channel access modes, and collision resolution. Resolutions adopted by the IEEE 802.14 Committee are illustrated after giving a protocol overview. Key resolutions include compensating round trip correction (RTC), interleaving minislots of data and request concurrently, and resolving collisions by multiple collision resolution engines, using the n-ary tree plus p-persistence algorithm with a first transmission rule. A comparative summary of some draft proposals that lead to the standard is given. Finally, we pinpoint two headend algorithms, minislot allocation and request scheduling, which are left open in the standard. They do not affect interoperability but may have a critical impact on performance. 相似文献
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