灾难恢复一键通

惠普公司即将推出第一款支持 DDS-4标准的磁带机产品——SureStore DAT40,它的容量达到了40GB,传输速度可达6MB/s。DAT40集成了惠普所独有的单键灾难恢复(OBDR,One-Button Disaster Recovery)技术,OBDR 技术是业界第一个基于硬件的单键灾难恢复解决方案,它可以使服务器或桌面系统在数据被破坏后最快速、最简单地恢复到正常的工作状态。用户只需点击一个按键就可以使系统恢复到最后一次备份的情况。这样用户就不必再为操作系统创建独立备份软盘,也不必在系统升级时再升级备份了。OBDR 技术将会用在适合于中小型网络使用的 SureStore DAT8、DAT24和 DAT40产品中。     

OBDR“抗虫”现身手——惠普首推单键灾难恢复技术

记者王鹏报道“机”有不测风云。上周的 CIH 病毒让所有计算机用户都有了劫后余生的体验,与此同时惠普公司适时推出了单键系统灾难恢复(OBDR)技术,用户只需在灾难发生后,按下 SureStore DAT8和 DAT24上的一个键,就可完成系统的全面恢复。惠普的 DAT8和 DAT24是业界第一个硬件本身就能实现单键恢复的磁带备份解决方案,这将使用户在系统遭到病毒破坏、系统崩     

民航甚高频通信系统PTT信号在E&M信令下的传输与控制

本文对民航甚高频通信系统PTT信号在EM信令下的传输与控制研究时,首先分析了EM信令,其次分析了民航甚高频通信系统PTT的启动方式,最后探讨分析了民航甚高频通信系统PTT信号在EM信令下的传输和控制。     

低端磁带开始格式大战

在低端磁带机市场前景看好的时候,原本作为开放格式在低端磁带市场称雄的DDS/DAT却已经进入了其生命周期的晚期,众多分析机构都认为DDS/DAT在市场上的需求量呈现下降趋势。     

分食低磁带市场——昆腾推出DLT-V4产品

“在2004年,低端磁带机市场占有率最大是DAT/DDS格式,达到了72%;DLTVS格式达到了15%。不过,DDS/DAT磁带技术在2000年、2001年达到高峰以后,整个技术呈现下滑趋势,供应商的数目也从2000年之前的3个变成了现在的1个。”昆腾公司亚太区市场总监Jim Simon说,“昆腾在10月18日推出的DLT-V4磁带机期望能与DAT/DDS分享市场份额。”昆腾表示,DLT-V4磁带机以与DAT160磁带相当的价格在低端磁带机市场上提供了企业级特性,包括DLTSage预测预防性诊断管理套件以及利用标准介质、拥有WORM(一次读多次写)功能满足法规遵从要求的DLTIce…     

基于ISO 11784/5的动物识别标签设计

在介绍ISO11784/5动物识别国际标准的基础上,通过对动物识别卡片结构的详细分析,以及对于可读写射频卡EM4205和读写基站EM4095的说明,给出一种利用EM4095基站将EM4205射频卡仿真制作为动物识别卡的设计方法。这种方法使得动物标签卡的制作更为灵活,满足了各动物标签使用国家和领域对其定义的自由度需求,是一种先进的卡片仿真设计方法。     

Seagate推出新品TapeStor DAT

Seagate公司8月26日推出两个专为网络后备设计的整体解决方案TapeStor DAT 8和TapeStor DAT 24。 TapeStor DAT方案包适用干Windows NT及Novell NetWare,拥有Seagate后备Exce单个服务器版本的所有规格。TapeStor DAT 8由SeagateScorpion 8 DAT驱动器和两个DDS-2磁带组成,TapeStorDAT 24则由Scorpion 24 DAT驱动器以及两个DDS-3磁带组成。TapeStor DAT还包括一盒清洁磁     

数字声频磁带录音机计算机接口板

数字声频磁带录音机、简称DAT,已广泛应用于专业录音并进入了家庭音响世界。一般DAT录音机为双通道输入,每通道采样率48kHz,A/D分辨率在16bit以上,记录动态范围在90dB以上。DAT盒带只有模拟盒带一半大小,而记录时间达二小时,可存储1200MB信息。因此,有越来越多的人把它作为高精度的声频数据记录仪应用于语音、水声、振动等科研领域。但是,目前计算机系统缺乏与之相应的接口板,它记录的数据不能直接送计算机内处理,妨碍了它的推广应用。为此,中科院声学所最近研制了一种PC总线的DAT计算机接口板。     

EM310无线模块与PIC单片机的接口设计

设计了一种利用PIC单片机控制EM310无线模块的系统.该系统可以实现用模块拨打电话(无语音)、发送接收短信、GPRS数据传输功能,具有结构简单、通用性强、工作稳定的特点.详细介绍了EM310模块的外围电路、与PIC单片机的接口电路设计及单片机发送AT指令的方法,并对EM310开发过程中容易出现的问题及解决方法进行了介...     

基于STM32单片机和EM310的无线终端设计

设计了一种基于STM32单片机和EM310模块的无线终端。通过STM单片机实现SCADA系统监测点仪表的串口与EM310之间的数据传输,通过EM310将仪表数据发送到GPRS网络,实现了监测点仪表与控制中心的无线连接。该终端适用于各种SCADA系统,具有结构简单、扩展性强、通用性强、建设成本低、传输容量大、传输高速等优点。     

基于蓝牙的设备管理信息系统研究

本文给出了一种基于蓝牙的设备管理信息系统的结构,分析了系统中设备管理信息卡与数据访问终端之间基于蓝牙协议的数据交换的过程,介绍了设备管理信息卡和数据访问终端的设计,最后指出在实现具体产品时仍需研究的问题。     

Spectral efficiency enhancement using an antenna‐based orthogonal frequency division multiaccess technique

An approach to enhance antenna spectral efficiency is proposed based on combining spacetime electromagnetic (EM) models of Tx/Rx antennas with orthogonal frequency division multiaccess (OFDM), leading to the EM‐OFDM, a technology capable of removing intersymbol interference (ISI) in high‐data rate communication links caused by the EM‐induced distortion antenna effects. The proposed approach differs from traditional OFDM in wireless communication in several aspects. First, the technique suggests a new decoupling approach by treating each given antenna transreceive device pair as a “stand‐alone channel” with its own distortion mechanisms considered separately from the propagation channel. Moreover, the deterministic distortion caused by the nonflat pure antenna EM filtration effects is exploited to carefully design a specialized OFDM transmission techniques based on the antenna parameters, not the multipath fading channels often invoked in conventional uses of OFDM methods. (The EM‐OFDM, however, can be combined with a traditional OFDM later if fading channels are present.) In this manner, a more efficient implementation of the wireless link equalization strategy may be enacted since the EM antenna origin of ISI is very different from the traditional propagation channel one. As a proof of concept, the proposed EM‐OFDM method is implemented for a single‐input‐single‐output link comprised of half‐wavelength linear wire antennas. A careful use of finite difference time‐domain to provide EM data allowed the construction of 64 decoupled “pure antenna OFDM subchannels.” Simulation results suggests that the antenna‐based OFDM system is capable of completely neutralizing all ISI effects caused by the limited antenna matching bandwidth of the transreceive wires, therefore, supporting considerably higher data rates with low symbol error rate (SER). A concrete evaluation of the SER using quadrature phase‐shift keying (QPSK) digital carrier modulation resulted in an increase of the effective antenna digital communication spectral efficiency by ratios up to 300%. Moreover, the EM‐OFDM error rate was found to be close to the ideal QPSK level or the maximum possible theoretical limit. Thus, combining detailed EM knowledge with standard signal processing methods can lead to considerable improvement in system design without modifying the antenna physical layout. The proposed approach is expected to play a role in the forthcoming 5G/6G and millimetre wave technology systems currently under development where there is a trend toward integration of EM and digital signal processing at the physical layer level.     

Design considerations for electromagnetic couplers in contactless power transmission systems for deep-sea applications

In underwater applications of contactless power transmission （CLPT） systems, high pressure and noncoaxial operations will change the parameters of electromagnetic （EM） couplers. As a result, the system will divert from its optimum performance. Using a reluctance modeling method, we investigated the gap effects on the EM coupler in deep-sea environment. Calculations and measurements were performed to analyze the influence of high pressure and noncoaxial alignments on the coupler. It was shown that it is useful to set a relatively large gap between cores to reduce the influence of pressure. Experiments were carried out to verify the transferring capacity of the designed coupler and system for a fixed frequency. The results showed that an EM coupler with a large gap can serve a stable and efficient power transmission for the CLPT system. The designed system can transfer more than 400 W electrical power with a 2-mm gap in the EM coupler, and the efficiency was up to 90% coaxially and 87% non-coaxially in 40 MPa salt water. Finally, a mechanical layout of a 400 W EM coupler for the underwater application in 4000-m deep sea was proposed.     

Attention and driving skills in aging and Alzheimer's disease.

The number of older drivers with dementia is rising with the aging of the adult population. A public health issue is growing because of concerns about the motor vehicle accident risk posed by drivers with dementia of the Alzheimer's type (DAT) and other progressive, degenerative dementias. However, little is known about the specific perceptual/cognitive deficits contributing to impaired driving in DAT. The present paper proposes, on both theoretical and empirical grounds, that attentional skills in relation to driving should be examined in older adults with and without DAT. Such investigations should focus on normal older adults and those in the mild, early stages of dementia because the latter are the most likely among the dementia population to be still driving. Evidence is presented indicating (1) that motor vehicle accident rates are related to performance on information-processing measures of different components of attention; (2) that this relationship is greatest for measures of the switching of selective attention and less for that of divided and sustained attention (vigilance); and (3) that many of these same attentional functions, and particularly the switching of visual selective attention, are impaired in the early stages of DAT and thus may contribute to increased accident risk. Further studies of cognitive and driving performance in older drivers are necessary to establish that the attentional impairments found in mild DAT contribute to increased accident risk. Implications of these findings for driver assessment, education, and training are discussed.     

New finite-dimensional filters for parameter estimation ofdiscrete-time linear Gaussian models

The authors derive a new class of finite-dimensional recursive filters for linear dynamical systems. The Kalman filter is a special case of their general filter. Apart from being of mathematical interest, these new finite-dimensional filters can be used with the expectation maximization (EM) algorithm to yield maximum likelihood estimates of the parameters of a linear dynamical system. Important advantages of their filter-based EM algorithm compared with the standard smoother-based EM algorithm include: 1) substantially reduced memory requirements, and 2) ease of parallel implementation on a multiprocessor system. The algorithm has applications in multisensor signal enhancement of speech signals and also econometric modeling     

Coupled nonlinear/electromagnetic CAD of injection‐locked self‐oscillating microstrip antennas

This article presents a systematic approach to the simulation and design of self‐oscillating integrated antennas, based on the combination of state‐of‐the‐art nonlinear and electromagnetic (EM) CAD techniques. The linear subnetwork, including the oscillator circuit and the antenna, is treated as a whole and its admittance matrix is computed at all frequencies of interest (including harmonics) by EM analysis. The oscillating subsystem is then analysed by harmonic balance (HB) for autonomous circuits. The design problem is turned into the solution of a nonlinear system, with a significant reduction in the overall number of EM analyses with respect to a conventional optimization. A simple linear model of the radiated far field in terms of the exciting voltages is generated by inexpensive post‐processing of the data generated by EM analysis. This allows the far‐field properties to be directly specified during the design step. The conditions for stable injection locking are then determined by nonlinear methods based on the numerical implementation of bifurcation theory. Finally, when the antenna is injection‐locked by a digitally modulated RF/microwave carrier, the system response in terms of radiated far‐field is efficiently computed by envelope‐oriented HB analysis. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13, 398–414, 2003.     

Efficient External Memory Algorithms by Simulating Coarse-Grained Parallel Algorithms

External memory (EM) algorithms are designed for large-scale computational problems in which the size of the internal memory of the computer is only a small fraction of the problem size. Typical EM algorithms are specially crafted for the EM situation. In the past, several attempts have been made to relate the large body of work on parallel algorithms to EM, but with limited success. The combination of EM computing, on multiple disks, with multiprocessor parallelism has been posted as a challenge by the ACM Working Group on Storage I/ O for Large-Scale Computing. In this paper we provide a simulation technique which produces efficient parallel EM algorithms from efficient BSP-like parallel algorithms. The techniques obtained can accommodate one or multiple processors on the EM target machine, each with one or more disks, and they also adapt to the disk blocking factor of the target machine. When applied to existing BSP-like algorithms, our simulation technique produces improved parallel EM algorithms for a large number of problems.     

Integrated structure-electromagnetic optimization of large reflector antenna systems

A novel multiparameter optimization method is developed for use with terrestrial and space reflector antenna electromechanical systems and other metallic and composite engineering structures. To satisfy extremely high design requirements, the proposed approach incorporates the objectives from various structural and electromagnetic (EM) performances of the system at many working/loading cases simultaneously. A finite element method is used for structural analysis. Optical ray tracing, spline function aperture field interpolation, geometric optics aperture integration, and FFT techniques are employed to analyse the EM performances of distorted reflector antennas. A systematic method is used for parameter profile analysis of the system. The optimization involves member size, structural geometric and material design variables. Various terrestrial and orbital working environments and loading cases which affect antenna performances can be included in the optimization model. The optimization of an 8 m antenna system, as an example, is discussed and the results are given.     

面向对象的图可视化系统设计与实现

阐述了一个小型图可视化系统的设计原理及方法。系统采用面向对象的方法设计并按照信息可视化模型分层架构,具有良好的可扩展性。系统支持随机布局、弹力模型、对称[1]等多种图形布局方式;并提供了对GML、DAT、TXT、自定义等多种图形数据封装格式的存取功能。     

A hybrid of electromagnetism-like mechanism and back-propagation algorithms for recurrent neural fuzzy systems design

This article introduces a novel hybrid evolutionary algorithm for recurrent fuzzy neural systems design in applications of nonlinear systems. The hybrid learning algorithm, IEMBP-improved electromagnetism-like (EM) with back-propagation (BP) technique, combines the advantages of EM and BP algorithms which provides high-speed convergence, higher accuracy and less computational complexity (computation time in seconds). In addition, the IEMBP needs only a small population to outperform the standard EM that uses a larger population. For a recurrent neural fuzzy system, IEMBP simulates the ‘attraction’ and ‘repulsion’ of charged particles by considering each neural system parameters as a charged particle. The EM algorithm is modified in such a way that the competition selection is adopted and the random neighbourhood local search is replaced by BP without evaluations. Thus, the IEMBP algorithm combines the advantages of multi-point search, global optimisation and faster convergence. Finally, several illustration examples for nonlinear systems are shown to demonstrate the performance and effectiveness of IEMBP.