基于PXA255的显示屏接口设计与驱动实现

本文介绍了Intel XScale PXA255处理器和嵌入式操作系统Windows CE在智能终端的应用。介绍了NEC公司的显示屏NL2432DR22与PXA255的连接电路的设计。分析了LCD驱动程序设计的要点,并能成功实现显示功能。     

基于XML的企业网络数据集成模型研究

随着企业信息化的逐步深入,企业内部及企业之间存在着大量的异构数据,数据集成问题是企业信息化建设所面临的问题之一。应用XML技术,提出了基于XML技术的企业数据集成模型的框架结构,对该框架的各个组成部分给出了说明以及所涉及的关键技术进行了研究。     

基于.NET平台和B/S结构的第三方客户端物流管理系统的设计

本文采用．NET平台和B／S架构对企业第三方客户端物流管理系统进行设计，对其中的问题提出改进方案，设计思路为：将企业产品放入第三方物流公司的就近库区，使企业把主要精力放在新产品的设计开发上，免除公司配备大量的仓储设施及运输车队所带来的费用和管理问题。     

一种基于多Agent的视频监控系统模型

在局域网多点视频监控系统中，当监控点和用户增加时视频数据在网络上的传播量会大大增加，将导致网络带宽严重不足，无法保证用户的QoS。该文针对此问题提出了基于多Agent的视频监控系统模型——MPMU(MultiPoint MultiUser)，用IDL(Interface Definition Language)对模型进行了描述，并在此模型中实现了QoS协商、重协商和基于MPEG—1数据流的丢帧机制。实验结果表明，此模型可以满足多监控点和多用户的需求。     

数据通信技术纵览

随着社会信息化进程的深入,数据通信技术获得了长足的发展,论文对数据通信技术的发展进行了回顾,并对几种主要的数据通信技术进行了比较。     

Response of framed buildings to excavation-induced movements

This paper presents a study of the influence of frame action on the response of buildings to deformations induced by deep excavations in soft clay. Using the finite element method, a building was modelled as a framed structure adjacent to a multi-propped excavation, firstly as a frame with continuous footings and then as a frame with individual footings. The geometry, location, and structural elements forming the frame models were varied to investigate the response of various frames. Using a structural analysis, parameters representing the stiffness of the frames in reducing deflection ratios and horizontal strains were derived. The influence of the frame action on the building stiffness can be quantified using the results from the finite element models. This makes it possible to estimate building modification factors from the relevant design charts so that induced deflection ratios and horizontal strains, caused by adjacent excavation and tunnelling activities, can be calculated. The approach gives a more realistic estimate of the tensile strains for assessing the potential damage caused to buildings.     

Channel measurement-based access point selection in IEEE 802.11 WLANs

With the wide deployment of IEEE 802.11 Wireless Local Area Networks, it has become common for mobile nodes (MNs) to have multiple access points (APs) to associate with. With the Received Signal Strength Indicator (RSSI)-based AP selection algorithm, which is implemented in most commercial IEEE 802.11 clients, the AP with the best signal strength is selected regardless of the candidate AP’s available throughput, resulting in unbalanced distribution of clients among the APs in the network. Several studies have shown performance improvement in not just the new MN (nMN), but also the network as a whole when the selection process considers the current load status of candidate APs. However, the proposed algorithms in these studies assume that there are no hidden terminal problems that severely affect the performance of the network. Hidden terminal problems frequently occur in wireless networks with unlicensed frequencies, like IEEE 802.11 in the 2.4 GHz band. Moreover, none of the previous studies have considered frame aggregation, a major improvement in transmission efficiency introduced and widely deployed with the IEEE 802.11n standard. In this paper, we propose a new AP selection algorithm based on the estimation of available throughput calculated with a model based on the IEEE 802.11 distributed coordination function in consideration of hidden terminal problems and frame aggregation. The proposed algorithm is evaluated through extensive simulation, and the results show that the nMN with the proposed AP selection algorithm can achieve up to 55.84% and 22.31% higher throughput compared to the traditional RSSI-based approach and the selection algorithm solely based on the network load, respectively.     

Relationship between static electrification of transformer oils with turbidity and spectrophotometry measurements

The paper presents the research results on electrostatic charging tendency (ECT) of transformer oil in a spinning disk system. The measurements were performed at different aging severity. Changes in static electrification were related to some classical aging indexes (conductivity, dissipation factor, water content, resistivity, etc.). Fast, inexpensive and reliable laboratory testing procedures developed by ASTM (D 6802 and D 6181) were also used to monitor the decay products as trace impurities. The obtained results show that static electrification currents increase with temperature, oil flow velocity, coating disk material properties and oil’s aging byproducts. The polarity, the amplitude and the time constant of the streaming electrification currents are also affected. This contribution is not only intended to provide a fresh review in this domain of research, but also contains a substantial amount of new material with a view of closing some gaps in the present state of knowledge of transformer oil streaming electrification phenomenon.     

Review of the recent developments in cellulose nanocomposite processing

This review addresses the recent developments of the processing of cellulose nanocomposites, focusing on the most used techniques, including solution casting, melt-processing of thermoplastic cellulose nanocomposites and resin impregnation of cellulose nanopapers using thermoset resins. Important techniques, such as partially dissolved cellulose nanocomposites, nanocomposite foams reinforced with nanocellulose, as well as long continuous fibers or filaments, are also addressed. It is shown how the research on cellulose nanocomposites has rapidly increased during the last 10 years, and manufacturing techniques have been developed from simple casting to these more sophisticated methods. To produce cellulose nanocomposites for commercial use, the processing of these materials must be developed from laboratory to industrially viable methods.     

浅谈PKPM框架结构设计注意事项

本文主要讲述在PKPM框架结构设计中注意的几个事项。从结构设计总说明各层布置图到基础平面图及详图几方面讲述。