Modeling Power Supply Noise in Delay Testing

Excessive power supply noise during test can cause overkill. This article discusses two models for supply noise in delay testing and their application to test compaction. The proposed noise models avoid complicated power network analysis, making them much faster than existing power noise analysis tools. can cause performance degradation and     

A Subcarriers Allocation Scheme for Cognitive Radio Systems Based on Multi-Carrier Modulation

Cognitive radio (CR) is a dynamic spectrum access technology as a solution to spectrum under-utilization problem in some licensed bands. Operating over an exceedingly wide spectrum, CR systems usually adopt multi-carrier modulation (MCM) to implement flexible channelization. Consequently, efficient channel allocation scheme becomes extremely important to an MCM based CR (MCM-CR) system. In this paper, a maximum likelihood detection model is developed to detect the presence and locations of licensed users (LUs) signals in the frequency domain. Performance of the detection model, including the optimal detection region, detection probability and false alarm probability, is analyzed. A one-order two-state Markovian chain model is proposed to predict channel status information. In particular, a novel subcarrier allocation scheme for MCM-CR systems is proposed, taking into account the confidence of channel estimation, quality of services (QoS) of rental users (RUs) and throughput. To validate the analytical results, simulations have been conducted to show effectiveness of the proposed scheme.     

论供电企业思想政治工作管理科学化

思想政治工作管理科学化,既是思想政治工作实践的重要方面,也是思想政治工作理论研究的重要内容.我们电力行业在创建国际一流企业,特别是在建立现代企业制度的今天,企业管理的科学化水平有了明显的提高,特别是世界先进的管理理论逐步在取代传统的管理方式方法.但企业在思想政治工作等方面的管理仍大多沿用一些传统的管理方法,与企业的其它管理相比较既显脱节又显滞后.因此,运用现代管理科学理论进行企业思想政治工作管理显得十分重要而迫切.     

Mitigation of polarization-mode dispersion in multichannel lightwave transmission systems

We propose a novel polarization-mode dispersion (PMD) compensation scheme for wavelength-division-multiplexing (WDM) systems, in which many WDM channels share one or a few PMD compensators at receiver site. It is shown, both analytically and numerically, that this scheme can achieve virtually the same performance as that using per-channel-based PMD compensation.     

Courtesy piggybacking: supporting differentiated services in multihop mobile ad hoc networks

Due to the salient characteristics such as the time-varying and error-prone wireless links, the dynamic and limited bandwidth, the time-varying traffic pattern and user locations, and the energy constraints, it is a challenging task to efficiently support heterogeneous traffic with different quality of service (CoS) requirements in multihop mobile ad hoc networks. In the last few years, many channel-dependent mechanisms are proposed to address this issue based on the cross-layer design philosophy. However, a lot of problems remain before more efficient solutions are found. One of the problems is how to alleviate the conflict between throughput and fairness for different prioritized traffic, especially how to avoid the bandwidth starvation problem for low-priority traffic when the high-priority traffic load is very high. In this paper, we propose a novel scheme named Courtesy Piggybacking to address this problem. With the recognition of interlayer coupling, our Courtesy Piggybacking scheme exploits the channel dynamics and stochastic traffic features to alleviate the conflict. The basic idea is to let the high-priority traffic help the low-priority traffic by sharing unused residual bandwidth with courtesy. Another noteworthy feature of the proposed scheme is its implementation simplicity: The scheme is easy to implement and is applicable in networks using either reservation-based or contention-based MAC protocols.     

北京火车站抗震鉴定与加固技术

北京火车站是首都重要的标志性建筑之一 ,195 9年建成 ,当时按 7度设防考虑 ,存在着许多不符合抗震要求的问题 ,一些设施也明显不能满足现代使用功能要求。北京火车站抗震加固与改造设计项目组 ,运用多种先进的加固手段 ,在保持原建筑外貌不变的前提下 ,实现了抗震能力和改善使用功能的协调 ,取得了大型公共建筑加固改造的新经验     

可燃性粉尘环境用电气设备标准介绍

章着重对可燃性粉尘环境用电气设备新标准（GB12476．1－2000和GB12476．2－2XXX）的主要内容进行了介绍，并对粉尘的爆炸机理，国内外粉尘标准体系等进行了阐述。     

石家庄市室内氡及其子体浓度

本文报道了用双滤膜法对石家庄市室内空气中氡及其子体浓度的调查结果。47个房间室内氡年平均浓度为17.0Bq·m~(-3),氡子体平均浓度是7.14Bq·m~(-3)。氡及其子体浓度的日变化是清晨4—8时出现峰值。季节变化是夏秋季低,冬季高,全年的最低值出现在8月,最高值出现在11月。     

脉冲相干激光雷达对运动目标成像模拟

针对运动目标，在考虑激光雷达方程、信噪比和自动增益、成像指标、噪声、图像处理等模块的基础上，对脉冲相干成像激光雷达进行了运动目标的成像模拟。     

后桥壳的可靠性优化设计

该文讨论了后桥壳的可靠性优化设计问题.在基本随机变量的概率特性已知的情况下,应用随机摄动法和约束随机方向法对后桥壳进行可靠性优化设计,并编制了实用的计算机程序,可以迅速准确地得到后桥壳的可靠性设计参数.