一种基于体系特性的SaaS系统评估框架

随着云计算、物联网和软件服务化等新技术的不断发展,在强调深入感知和互联互通互操作的过程中,SaaS应用系统越来越复杂,如何从体系的视角对这类软件系统的性能指标进行评估和预测成为新的研究方向。首先从体系的定义中抽取出体系独有的特征概念对SaaS系统进行描述,并根据体系特征间的依赖关系建立了SaaS系统评估框架,最后以SaaS系统CloudCRM为例,并利用文中的方法进行评估,验证了方法的可行性和有效性。     

金刚石薄膜的结构特征与电导率的相关性

讨论了ＣＶＤ金刚石薄膜作为半导体材料的一些基本特性，主要叙述了金刚石薄膜的生长习性和结构特征对其电性能的影响，即其电导率的“尺度交 ”和“晶面效应”，以及这些效应对由金刚薄膜制备的半导体器件性能的影响。     

基于GPRS远程温度采集网络的设计

利用DS18B20单总线温度传感器、PTR2000数传模块、GPRS传输模块GR64和AT89LV51微控制器构建的远程温度采集网络,具有无线传感器网络的一些特征和功能,能够较好实现分布式系统的无线温度采集和监控,实验结果表明,系统具有适应性强、传输速度快、可靠性高的特点。     

SPC的典型控制图的应用范围

研究了统计过程控制技术中的常规控制图、通用控制图、小波动控制图、多元控制图、选择控制图及其应用范围。     

Modeling of noninvasive microwave characterization of breast tumors

This paper describes an approach for the noninvasive microwave characterization of tumors in breast tissue. Tumors are modeled as lossy dielectric targets. Their complex natural resonances (CNR) can be extracted from the time-domain response and correlated with diagnostically useful properties. Finite-difference time-domain simulation is used to obtain the time-domain response from a tumor with a short electromagnetic pulse as an input. The normal breast tissue and tumor are modeled as dispersive media using the Debye model and CNRs are extracted using Prony's method. It is shown that the locations of the dominant CNRs are separated in the complex frequency plane as functions of the tumor dielectric properties. The technique has potential as a diagnostic tool to characterize breast lesions in conjunction with other imaging modalities such as ultrasound for detection.     

某型电台模拟训练器人机界面显示电路设计

介绍某型电台模拟训练器显示电路的设计过程。该电路以基于51内核的高性能单片机MSC1210单片机作为主控单元，通过虚拟I^2C总线（Inter IC BUS）控制数码管驱动芯片SD7218，实现实际装备的频率及工作状态显示、存贮、调用及出错信息提示等功能，同时通过串行接口连接网络通信单片机实现与主控计算机的互联。     

STUDIES OF THE DYNAMIC BEHAVIORS OF A CLASS OF LEARNING ASSOCIATIVE NEURAL NETWORKS

This paper investigates exponential stability and trajectory bounds of motions of equilibria of a class of associative neural networks under structural variations as learning a new pattern. Some conditions for the possible maximum estimate of the domain of structural exponential stability are determined. The filtering ability of the associative neural networks contaminated by input noises is analyzed. Employing the obtained results as valuable guidelines, a systematic synthesis procedure for constructing a dynamical associative neural network that stores a given set of vectors as the stable equilibrium points as well as learns new patterns can be developed. Some new concepts defined here are expected to be the instruction for further studies of learning associative neural networks.     

Photoshop应用漫谈

本文主要介绍了Photoshop学习方法、学习心得及一些不易发现的功能使用方法.     

Reduction of Facet Reflectivity of Quantum-Cascade Lasers With Subwavelength Gratings

We demonstrate the reduction of the facet reflectivity of quantum-cascade lasers (QCLs) by using subwavelength gratings. The gratings were fabricated on lambda=4.9- and 9.8-mum QCLs using focused ion beam milling. Reflectivities as low as 1%-3% for the 4.9-mum QCL and as low as 4%-8% for the 9.8-mum QCL are reported     

嵌入式技术发展状况综述

嵌入式系统与我们的生活息息相关。单片、嵌入、物联是嵌入式系统的三个基本特性。随着嵌入式系统向着高集成、多功能、微型化、网络化、低成本、低功耗的方向发展,嵌入式系统的技术革新也日新月异。文章主要研究了嵌入式系统的应用领域及特点,以及嵌入式技术发展的技术环境。最后论述了嵌入式产业的地位和发展状况以及嵌入式工程师面临的问题。     

噪声对人类听觉的损伤

探讨了噪声对人类听觉造成的损失和损伤,以及高强度噪声导致耳聋等相关问题;在此基础上测量和分析了社会噪声、交通噪声等对人类听觉损伤较大的噪声。     

单片机在烤烟炕房温度测量和控制中的应用

为了提高烟叶的初烤质量，烤房的温度的测量方法、控制方法和精度等诸多方面需要得到改善和提高。文中介绍了以单片机为核心的温度控制装置。实践证明该装置控制性能良好。     

On the convergence of the scattering statistics of finite number of randomly oriented dipoles to Rayleigh

For randomly oriented half-wavelength dipoles, the scattering statistics of an ensemble, containing as few as five members, is shown to be indistinguishable from Rayleigh statistics, which is the limiting form as the number of scatterers becomes infinite.     

建筑外窗保温性能检测装置测控系统的设计与实现

以建筑节能为目的,介绍了一种建筑外窗保温性能检测装置测控系统的设计与实现。依照现场总线的技术要求,系统硬件采用通用微型计算机为主机,各种测控仪表为从机,双绞线为传输介质,按照RS-232／RS-485串行总线标准及接口技术实现主从机之间的信息交换。讨论了在Visual C＋＋开发平台下,利用串口类CSerialPort实现多串口通信,以及多线程、数据库、打印等功能的实现。实现了根据国家标准GB／T8484-2002的要求完成的测控功能。     

喇叭共振和预防研究

基于喇叭的共振原理,提高扬声器的发声强度并尽可能的降低因振动而消耗的能量,从而提高喇叭的效率。依照理论计算数据作为后续试验基础,通过多组试验对比,分别对输入谐振频率进行调节,来检测各组试验的音量即声能。试验结果表明当输入谐振频率与喇叭的固有频率相同时,喇叭出现共振,此时检测喇叭的声能是相对较弱的。     

Transfer matrix of a Dirac-like singularity of the dielectricpermittivity

We derive the general expression, for TE-polarization, of the transfer matrix associated to a Dirac-like singularity of the dielectric permittivity. We show that this approach is successful in modeling quantum wells, as well as localized loss centers used for the “modal sculpturing” in semiconductor lasers. Its range of validity includes any discontinuity of finite length as long as its actual extension remains much inferior to the optical wavelength     

Evaluation of reliability and safety of long-term unmaintained computer systems

In many applications such as critical life-saving systems, safety is an important design issue as well as reliability. Among various commonly-used approaches in the implementation of on-line unrepairable fault-tolerant systems, standby systems achieve the most satisfactory reliability figure, followed by duplex systems, hybrid systems and triple modular redundancy. Nevertheless, the safety figure of duplex systems is superior to that of the standby approach. In this paper, the failure rate of system modules and hard core is predicted by the M1L-HDBK-217E model, and we show that the reliability and safety figure of cold standby systems can be further dramatically improved by increasing the number of spare units. Furthermore, comparative measures such as the reliability improvement factor, the safety improvement factor and the mission time improvement factor are proposed for showing that long-term unmaintained systems have reliability and safety as high as other systems that must be repaired.     

The greening of television

That big liquid-crystal display in your new TV may be twice as efficient as the old cathode-ray tube was, but because it's much larger, it may be using as much energy as your old set--or even more.     

Model-based reconstruction of multiple circular and ellipticalobjects from a limited number of projections

We consider tomographic image reconstruction from a limited number of noisy projections. An efficient algorithm based on maximum likelihood estimation (MLE) is developed to reconstruct images of multiple discs with unknown locations and radii. The algorithm is successfully applied to images with signal-to-noise ratio (SNR) as low as 0 dB, using as few as 16 projections, and containing as many as twelve discs with widely varying radii. Experimental results show that our approach significantly outperforms conventional convolution back projection. The algorithm is successfully extended to the multiple ellipse case.     

Role of molecular beam epitaxy in the field of optoelectronics

This article reviews the role of molecular beam epitaxy (MBE) in the field of optoelectronics. In the past 25 years, this crystal growth technology has helped researchers to investigate important physical phenomena related to materials properties. In particular, success in engineering the band structure and refractive index was a key to the exploration and development of carrier transport devices such as high-mobility, bipolar and tunnel transistors, as well as optoelectronic elements such as LEDs, lasers, modulators and photodetectors. Because of its relatively simple growth process, excellent growth control and ability to characterize growth-related phenomena in situ, MBE initiated many important research fields such as GaAs on silicon, fast optical switches and detectors, and vertical cavity and edge-emitting quantum well lasers, particularly in the GaAs/AlGaAs materials system. In addition, relatively unexplored systems such as II/VI materials, nitrides or even Si/Ge heterostructures, are currently hot topics among MBE crystal growers.

Over the years, the division of the roles of MBE as a research and prototyping tool and metal-organic vapor-phase epitaxy (MOVPE) as a production tool has become well established. However, for certain production processes, specifically compact disc and 980 nm Er-fiber pump lasers, MBE has been proved to be as good or better than MOVPE, even when high throughput is a necessity. New fields, such as devices based on very precise vertical Fabry-Perot cavity designs and low-temperature GaAs, are emerging in which the uniform thickness control, in situ monitoring capability and low-temperature growth ability of MBE offer clear superiority over MOVPE for eventual production.