提高系统容错性的软件技术

计算机在现代军事装备中的作用日益重要,他在装备研制中所占工作量的比例越来越大。由于军用计算机的工作环境一般较恶劣,常容易引起计算机电源不稳定等问题,因此,如何保证计算机系统的可靠性已成为影响装备质量的关键因素。本文综合分析嵌入式系统中提高计算机容错性的常用技术,并给出采用软件恢复块实现掉电恢复的实例。     

软交换容灾浅析

从技术角度对软交换的容灾备份方式、备份机制作了较详细的分析：     

An integrated 0.35 μm CMOS optical receiver with clock and data recovery circuit

This paper presents an integrated optical receiver that operates at 1 Gb/s in a standard 0.35 μm digital CMOS technology. The receiver consists of an integrated CMOS photodetector, a transimpedance amplifier (TIA) followed by a post-amplification stage and a dual-loop clock and data recovery (CDR) circuit. At a wavelength of 860 nm, the circuit requires an average light input power of −19.7 dBm to obtain a bit-error rate (BER) of 10⁻¹². The complete receiver consumes a total power of approximately 155 mW from a 3.3-V supply. The core circuit area is 0.85×1.32 mm².     

关于具有恢复消息功能的认证方案的一点注记

简述了基本的Nyberg-Rueppel认证方案和HMP认证方案,指出了LC认证方案是HMP认证方案的一个特例。     

一种基于PLL的CBR业务时钟恢复方案

信元在 ATM 网内传输时,由于网内缓存的存在,造成了信元延时变化。信元延时变化对基于锁相环(PLL)的恒定比特率业务时钟的恢复有很大影响,即时钟的抖动和漂移比较明显。从而使这种基于 PLL 的CBR 业务时钟恢复方案在某些场合不能应用。本文提出了一种基于 PLL 的时钟恢复新方案,该方案可以明显地降低由于信元延时变化而造成的 CBR 业务时钟的抖动和漂移,同时不增加缓存的容量。     

Optical-LSP Establishment and a QoS Maintenance Scheme Based on Differentiated Optical QoS Classes in OVPNs

A virtual private network (VPN) over Internet has the benefit of being cost-effective and flexible. However, it has difficulties providing sufficient QoS and adequate transmission capacity for high bandwidth services. Given the increasing demand for high bandwidth Internet and the demand for QoS assurances in a VPN over Internet, IP/generalized multi-protocol label switching (GMPLS) based on a control plane combined with a high-bandwidth, dense-wavelength division multiplexing (DWDM) optical network is seen as a very favorable approach for realizing the future optical VPN (OVPN) over IP/GMPLS over DWDM. Within this architecture, providing QoS guaranteed multimedia services with a differentiated QoS guaranteed protocol framework with QoS recovery is one of the key issues to implement. Therefore, we suggest in this paper optical-label switched path (O-LSP) establishment and its QoS maintenance scheme based on differentiated optical QoS-service (DOQoS) classes. They are the key components for this DOQoS framework in assuring end-to-end QoS in an OVPN over IP/GMPLS over DWDM architecture.     

LINUX下一种改进的音频会议系统的实现方法

提出了一种计算缓存区大小的改进方案．根据RTCP包中反馈回的丢包率,动态地改变音频数据的发送策略,有区分地采取差错控制手段,提高了网络带宽的利用率．在此基础上,设计了一个以RTP协议为基础的音频会议系统的模型,并在Linux平台上用多线程的方法实现了各个模块．模拟实验表明,该系统能自适应地调整缓存区大小和数据包的发送策略,在实时性及带宽资源的利用上都达到了较理想的效果．     

All first-order averaging techniques for a posteriori finite element error control on unstructured grids are efficient and reliable

All first-order averaging or gradient-recovery operators for lowest-order finite element methods are shown to allow for an efficient a posteriori error estimation in an isotropic, elliptic model problem in a bounded Lipschitz domain in . Given a piecewise constant discrete flux (that is the gradient of a discrete displacement) as an approximation to the unknown exact flux (that is the gradient of the exact displacement), recent results verify efficiency and reliability of

in the sense that is a lower and upper bound of the flux error up to multiplicative constants and higher-order terms. The averaging space consists of piecewise polynomial and globally continuous finite element functions in components with carefully designed boundary conditions. The minimal value is frequently replaced by some averaging operator applied within a simple post-processing to . The result provides a reliable error bound with .

This paper establishes and so equivalence of and . This implies efficiency of for a large class of patchwise averaging techniques which includes the ZZ-gradient-recovery technique. The bound established for tetrahedral finite elements appears striking in that the shape of the elements does not enter: The equivalence is robust with respect to anisotropic meshes. The main arguments in the proof are Ascoli's lemma, a strengthened Cauchy inequality, and elementary calculations with mass matrices.

     

Effect of aggregation on population recovery modeled by a forward-backward pseudoparabolic equation

In this paper we study the equation

in a bounded domain of , , with homogeneous boundary conditions of the Neumann type, as a model of aggregating population with a migration rate determined by , and total birth and mortality rates characterized by . We will show that the aggregating mechanism induced by allows the survival of a species in danger of extinction. Numerical simulations suggest that the solutions stabilize asymptotically in time to a not necessarily homogeneous stationary solution. This is shown to be the case for a particular version of the function .

     

2.5Gb/s 0.18μm CMOS时钟数据恢复电路

采用TSMC公司标准的0．18μm CMOS工艺，设计并实现了一个全集成的2．5Gb／s时钟数据恢复电路．时钟恢复由一个锁相环实现．通过使用一个动态的鉴频鉴相器，优化了相位噪声性能．恢复出2．5GHz时钟信号的均方抖动为2．4ps，单边带相位噪声在10kHz频偏处为-111dBc／Hz．恢复出2．5Gb／s数据的均方抖动为3．3ps．芯片的功耗仅为120mW．