软件项目实训教学的虚拟公司模式探索

项目实训是深化专业知识理解,提高实践能力的重要手段。为提升教学效果,改善实训的逼真程度,针对软件项目实训的需求提出了虚拟公司项目实训教学模式。首先对虚拟公司项目实训教学的发展进行了梳理,着重对虚拟公司的组织,教学组织与管理,学习效果评价等具体环节进行了设计和讨论。最后总结了该教学模式对于学生专业能力提升的作用。     

一种太阳能供电LED照明系统电路设计

文章以太阳能供电的LED照明系统为研究对象,探讨了其基本构成,重点探讨了太阳能充电控制器的设计及其电路实现。设计了以PWM控制器CS51221为控制核心的充电控制器的电路,探讨了相关元器件参数的计算方法：分析了LED照明驱动系统的组成及其功能,设计了以NCP3066为核心的LED驱动电路、光敏二极管开关电路、PWM波调光电路;完成了简易太阳能供电LED照明系统电路的硬件,并对其功能及工作性能参数进行了测试和分析。结果表明,该LED照明系统满足设计要求,系统运行良好。     

流量经营要素分析及对业务支撑系统的要求

在各大运营商纷纷提出流量经营概念的背景下,探讨了如何做好流量经营的产品设计运营和业务支撑系统（BSS）的规划,并对具备纳入产品设计中的经营要素进行了分析,提出了智能管道PCC架构体系下的BSS规划定位和改造建议。     

Adaptive clutter suppression based on iterative adaptive approach for airborne radar

To improve the performance of the recently developed weighted least-squares-based iterative adaptive approach (IAA) in space–time adaptive processing (STAP) for weak or slow targets detection, we propose a novel IAA scheme to adaptively suppress the ground clutter by using the secondary training data (STD). Especially, we use the IAA to estimate the clutter plus noise covariance matrix from a very small number of STD. The resulting clutter plus noise covariance matrix can be utilized to form the STAP filter and then suppress the clutter. To reduce the computational complexity of the IAA, we exploit the sparsity of large clutter components in the angle-Doppler image and develop a modified IAA algorithm employing a soft-thresholding to adaptively determine the entries of each iteration that should be updated. Simulation results show that our proposed scheme outperforms the conventional IAA scheme over weak or slow targets detection and the modified IAA algorithm exhibits a comparable or even a better performance than the IAA algorithm but a lower computational complexity.     

基于AT89C51单片机的十进制计算器系统设计

本设计是基于AT89C51单片机进行的十进制计算器系统设计,可以完成计算器的键盘输入,进行加、减、乘、除4位无符号数字的简单四则运算,并在LED上相应的显示结果。硬件方面从功能考虑,首先选择内部存储资源丰富的AT89C51单片机,输入采用4×4矩阵键盘。显示采用4位7段共阳极LED动态显示。软件方面从分析计算器功能、流程图设计,再到程序的编写进行系统设计。     

Red,Green, and Blue Light‐Emitting Polyfluorenes Containing a Dibenzothiophene‐S,S‐Dioxide Unit and Efficient High‐Color‐Rendering‐Index White‐Light‐Emitting Diodes Made Therefrom

A series of blue (B), green (G) and red (R) light‐emitting, 9,9‐bis(4‐(2‐ethyl‐hexyloxy)phenyl)fluorene (PPF) based polymers containing a dibenzothiophene‐S,S‐dioxide (SO) unit (PPF‐SO polymer), with an additional benzothiadiazole (BT) unit (PPF‐SO‐BT polymer) or a 4,7‐di(4‐hexylthien‐2‐yl)‐benzothiadiazole (DHTBT) unit (PPF‐SO‐DHTBT polymer) are synthesized. These polymers exhibit high fluorescence yields and good thermal stability. Light‐emitting diodes (LEDs) using PPF‐SO25, PPF‐SO15‐BT1, and PPF‐SO15‐DHTBT1 as emission polymers have maximum efficiencies LE_max = 7.0, 17.6 and 6.1 cd A^?1 with CIE coordinates (0.15, 0.17), (0.37, 0.56) and (0.62, 0.36), respectively. 1D distributed feedback lasers using PPF‐SO30 as the gain medium are demonstrated, with a wavelength tuning range 467 to 487 nm and low pump energy thresholds (≥18 nJ). Blending different ratios of B (PPF‐SO), G (PPF‐SO‐BT) and R (PPF‐SO‐DHTBT) polymers allows highly efficient white polymer light‐emitting diodes (WPLEDs) to be realized. The optimized devices have an attractive color temperature close to 4700 K and an excellent color rendering index (CRI) ≥90. They are relatively stable, with the emission color remaining almost unchanged when the current densities increase from 20 to 260 mA cm^?2. The use of these polymers enables WPLEDs with a superior trade‐off between device efficiency, CRI, and color stability.     

程序切片技术在程序理解中的应用

随着计算机软件技术的飞速发展,软件系统的规模变得越来越大,软件的维护工作也随之越来越复杂。绝大部分软件开发的主要精力都消耗在维护或者扩展原有的系统上面,而不是重新开发新系统。因此,对于软件系统的维护问题变得极其重要,对于遗留软件的维护、理解在软件开发过程中已经变得越来越重要。分别介绍了程序理解的模型及工具,并结合程序切片技术探讨程序切片在程序理解中的应用。     

基于CODE Ⅴ的手机摄像镜头光学设计

为了满足市场对微型、简单化手机摄像镜头的需求,运用光学设计软件CODEⅤ,结合非球面透镜理论,设计出用于可见光波段且符合结构简洁、生产成本低的要求的手机定焦镜头。该镜头F数为2.05,视场角为62°,半像高为2.4mm,系统总长度为5.59mm。为了使结构紧凑并且最大限度地降低生产成本,在结构设计中采用非球面的塑料镜片。设计结果显示:镜头的适应像素尺寸是1.1μm×1.1μm,相应的尼奎斯特频率为454lp/mm,在1/2尼奎斯特频率处绝大部分视场调制传递函数(MTF)值大于0.4,各个视场的横向像差均小于9.26μm,均方根(RMS)半径都在艾里斑之内,畸变小于1%,获得良好的成像效果。     

Antenna subset selection at multi‐antenna relay with adaptive modulation

In this paper, we proposed several antenna selection schemes for cooperative diversity systems with adaptive transmission. The proposed schemes were based on dual‐hop relaying where a relay with multiple‐antenna capabilities at reception and transmission is deployed between the source and the destination nodes. We analyzed the performance of the proposed schemes by quantifying the average spectral efficiency and the outage probability. We also investigated the trade‐off of performance and complexity by comparing the average number of active antennas, path estimations, and signal‐to‐noise ratio comparisons of the different proposed schemes. Copyright © 2011 John Wiley & Sons, Ltd.     

针对PMOS应用的TiN金属栅功函数调节

PMOS管需要金属栅的功函数接近硅的价带边,所以寻找到合适的方法调节TiN的功函数使之正向移动是金属栅工程的重点,也是难点。本文详细研究了TiN金属栅的厚度,栅介质沉积后退火,氧引入,以及N含量变化对TiN功函数的影响。发现随着TiN的厚度变厚,功函数会正向移动,但是在某一个厚度会达到饱和,另外,在少量氧气氛围下的栅介质沉积后退火,也能使功函数正向移动,而在TiN中引入氧元素,以及增大N的含量都会使TiN的功函数正向漂移。以上所述方法都能有效的调节TiN的功函数来适应PMOS的需要。