基于中间件的故障注入技术在嵌入式软件逻辑覆盖测试中的应用

以使用中间件故障注入增加软件测试覆盖率为目的,对故障注入技术和原理进行了介绍;并通过实际工程例子提出了一种基于中间件故障注入技术的应用,同时比较了采用故障注入技术后的软件逻辑覆盖测试结果与使用常规测试手段进行的覆盖测试结果,为嵌入式软件的逻辑覆盖测试提供了一种便利、有效的方法。     

油井井下高温度和压力测试系统研究与应用

为了对井下温度压力参数测试系统进行研制,采用铂电阻和蓝宝石硅晶体作为前端传感器,系统采用井下直接测量,避免通过中间介质进行传导,可实现较小误差。恒流源驱动方式使采集前端信号工作稳定,采用时间同步的方式将采集信号与深度关联,数据分析时能够绘出温度压强随油井深度变化的曲线,实现精确测量,掌握地层分布规律。     

水声信号的非高斯特性分析与检测方法的研究

本文研究了海洋环境噪声和船舶噪声的高斯性,通过实验研究发现,纯净的海洋环境噪声(夜晚无行船时)呈现出高斯性,反之是非高斯;船舶噪声是服从非高斯的,另外无论海洋环境噪声,还是船舶噪声,在相等样本长度下,在不同频段的高斯性上也有差异,分析频段越低,统计量越大,反之统计量越小.基于高阶累积量T2在船舶由远及近的过程中的变化规律,研究了非高斯背景下非高斯信号的一种检测方法,即在海洋环境噪声下检测船舶噪声的方法.通过实船实验得到了满意的结果.     

基于间歇耦合和广义混沌同步的数字信号传输方案

该文讨论了一种基于间歇耦合思想和广义混沌同步的保密通信方案。在这种数字信号传输过程中,每个信号周期被分为两部分T1,T2,分别用于实现同步和信号提取,分析了T1,T2与安全性能和信息解调精度的关系。数值仿真表明效果良好。     

Real People Meeting Virtually Real People — a Review of Some Experiments in Shared Virtual Environments

This paper reports on experimental studies looking into the experience of people who are collaborating in shared virtual environments. In these environments, people are represented as 'avatars' in virtual space. The studies reported here suggest that the way in which people are represented has a strong effect on others' perceptions. The effects on the feeling of closeness or 'accord' of people who meet in this way are contrasted with more natural real-life meetings where all the normal social cues are available. The characteristics of the systems used to access the shared virtual environment are considered. Different systems offering differing degrees of perceived 'immersion' in an environment are discussed, and their effects on social behaviours such as leadership are considered.     

“通信原理”课程教学质量指标体系的构建与评价

授课质量评价是检验教学质量的有效方法。本文结合＂通信原理＂课程的教学现状,建立了一种教学质量评价指标体系,确定了影响教学质量的因素。我们采用模糊数学理论,给出了多级模糊综合评判模型及模糊评判矩阵,用Delphi法确定了主因素权重系数,以模糊度量方式评价了＂通信原理＂课程教学质量。实例分析结果验证了本文所述方法能减少评估中的主观影响,提高了评估的准确性和公正性。     

光纤电流传感器检测系统的分析

本文给出了光纤电流传感器的两种检测方案:单路检测系统和双路检测系统。比较了他们的各自特点。分析表明:双路检测系统有较高的信噪比,较强的抗干扰能力,不仅可以探测交流大电流,也可用于测量直流大电流,是目前光纤电流传感器信号检测的较好方案之一;单路检测系统具有结构简单,调整方便,对探测器、放大器无特殊要求等优点,在其它光纤传感系统中(如光纤电压计)具有实用意义。     

图像压缩与增强

为了存储、处理和传输一些图像数据，必须要对图像进行压缩，利用哈夫曼进行无损压缩编码是可行的方法。图像增强的目的主要是改善图像质量，常用的图像增强技术有图像数据统计分析处理、直方图修改、图像平滑滤波等，这里主要介绍了直方图的均衡化和图像的均值滤波。     

Methods for physical impairment constrained routing with selected protection in all-optical networks

In this paper, we investigate the problem of survivable all-optical routing in WDM networks with physical impairments. One of the recent key issues in survivable optical network design refers to maximization of the ratio of routeable demands while keeping the overall network cost low. In WDM networks, this goal can be achieved by routing as many demands in all-optical way as possible. Based on the latest technical trends driven by deployment costs, technical constraints, and backward compatibility, this will not mean that all demands will be routed in all-optical way in the near future. Nowadays, operators are mostly willing to dedicate only a given ratio of their power budget to all-optical routing. This in turn implies a new problem to be solved: operators have to find a way to select demands that should be routed in all-optical way and which should not. The problem gets even more complicated, if we add demand protection issues. In this paper, we introduce and evaluate methods able to maximize the number of demands routed with protection in all-optical way in capacity-constrained networks with limitations on path lengths according to physical impairments.     

Fuzzy logic arbiters for multiple-bus multiprocessor systems

This paper describes and evaluates the use of fuzzy logic arbiters for multiple-bus shared memory multiprocessor system. Multiple-bus systems allow multiple and simultaneous bus transfer in addition to a high degree of fault tolerance. In such systems, arbiters are used to resolve conflicts to system resources, which are the shared memory modules and the buses. Typically, these conflicts are resolved by using two-stage arbitration schemes that employ policies such as random choice, daisy chaining, round-robin, etc. A new way of implementing these arbiters is the use of fuzzy logic to resolve resource request conflicts based on the system state and performance variables. This paper describes a new technique for implementation of fuzzy logic in the system arbiters and presents a simulation program that evaluates the system performance. The program is coded in such a way as to accommodate any arbitration scheme, from which the fixed priority and fuzzy priority have been implemented. Parameters affecting multiple-bus system performance are considered and used as inputs to the fuzzy arbiters. The inputs are fuzzified by using appropriate membership functions, and rules have been defined in such a way as to increase and distribute evenly the acceptance probability of each processor in the system. Results from the simulation program using a prioritized arbitration scheme are compared against other published results and show very close agreement. Furthermore, results show an increase in the acceptance probability of the processors using fuzzy arbiters.     

液晶显示技术（上）

本文系统地介绍了扭曲向列型（ＴＮ）、超扭曲向列型（ＳＴＮ）和有源矩阵型（ＡＭ）液晶显示器的典型结构、工作原理、性能特点和制造技术及液晶显示器的应用与发展。另外，对液晶材料和彩色滤色器也作了简要介绍。     

MMSPEED: multipath Multi-SPEED protocol for QoS guarantee of reliability and. Timeliness in wireless sensor networks

In this paper, we present a novel packet delivery mechanism called Multi-Path and Multi-SPEED Routing Protocol (MMSPEED) for probabilistic QoS guarantee in wireless sensor networks. The QoS provisioning is performed in two quality domains, namely, timeliness and reliability. Multiple QoS levels are provided in the timeliness domain by guaranteeing multiple packet delivery speed options. In the reliability domain, various reliability requirements are supported by probabilistic multipath forwarding. These mechanisms for QoS provisioning are realized in a localized way without global network information by employing localized geographic packet forwarding augmented with dynamic compensation, which compensates for local decision inaccuracies as a packet travels towards its destination. This way, MMSPEED can guarantee end-to-end requirements in a localized way, which is desirable for scalability and adaptability to large scale dynamic sensor networks. Simulation results show that MMSPEED provides QoS differentiation in both reliability and timeliness domains and, as a result, significantly improves the effective capacity of a sensor network in terms of number of flows that meet both reliability and timeliness requirements up to 50 percent (12 flows versus 18 flows).     

基于直流无刷电机的雷达伺服系统设计

介绍了连续扫描工作的长寿命伺服系统设计与实现,选用无刷电机作为执行元件并选用无刷旋转变压器作为测角反馈元件来实现长寿命要求。文中描述了直流无刷电机的Matlab模型和基于无刷电机的雷达伺服系统仿真模型。伺服系统的校正运算通过PI调节器实现,参数通过系统仿真决定,简化了系统参数的设计。仿真模型中考虑了结构谐振,用以保证调节器的可实现性。功放电路由单路PWM经FP—GA分离出6路开关信号来控制,简单可靠。从系统的实际工作数据结果来看达到了较好的控制性能。     

起伏地形双向抛物线方法的计算与验证研究

双向抛物线方法是复杂环境下电波传播计算中的一种重要方法,提出一种新的不规则地形下双向抛物线方程用于电波传播的计算方法,该算法在求解过程中记录了所有波源的历史路径,结合具体路径对双向抛物线方法进行相位修正,并在步进过程中,对不同极化下障碍物表面的边界条件进行了重新处理,对目前采用的阶梯模型进行了改进。在此基础上,提出使用矩量法来精确验证近距离不同极化下双向抛物线方法的计算精度。通过实例分析,证明了起伏地形下新算法计算的精确性。     

高重复频率脉冲激光谱线宽度的测量方法

本文介绍了一种用扫描标准具配合检测系统测量重复频率脉冲激光线宽的方法,分析了造成测量误差的几种相关因素,并指出了测量中应该注意的几个问题,实验测定了几种不同染料激光器输出激光的线宽.     

A new model for fault and availability in complex multimedia services

The definition of fault and availability in systems that offer simple services tends to be binary and static. This is because 1) systems that offer simple services are operative if and only if all the parts of the system are in full operative condition and 2) faults can be defined by the service providers regardless of the context in which the service is used. In the case of complex multimedia services however, even when parts of the system are not available, the service is still worth offering. Moreover, the definition of the level of failure at which the service should be declared as unavailable is user and context dependent. In this paper we introduce a new way of defining fault and availability that is appropriate for systems that offer not only simple but also complex multimedia communication services. Our model provides ways of capturing in a useful way 1) the difference between functionally identical faults that appear in different applications, 2) the difference between faults that although they are functionally identical, they have different roles and significance in the application, 3) the change in the value of providing certain resources, depending on the availability of other resources, 4) the difference in the value of providing certain resources depending on the preferences of the users. Our model takes into consideration the user's point of view as far as availability and fault tolerance are concerned. It also provides different degrees of fault and availability (as opposed to binary definition of faults). We use these definitions to allocate the available resources to support the different parts of the system in a provably optimal way, i.e., in a way that maximizes the expected value of the offered service. This revised version was published online in June 2006 with corrections to the Cover Date.     

一种基于预约的无线传感器网络MAC协议

无线传感器网络要求的能量高效,低延时,使得MAC协议的设计充满挑战。近来已经提出了很多基于簇的MAC协议,为减少冲突在簇内部采用TDMA方式来协调簇内各个节点的传输。提出了一种在采用簇结构的基础上,使用预约方式来发送数据的R-MAC（Reservation-MAC）协议。当争用节点少的时候,采用随机争用方式来预约数据的发送;在争用节点多的时候,采用时隙争用方式来预约数据的发送。分析表明,R-MAC能够有效地降低能耗和减少延迟。     

Trench VDMOS制造流程中多晶相关工艺问题研究

Trench VDMOS的制造流程中,要进行多晶的淀积、回蚀、清洗,其效果的好坏会直接影响到器件的电学参数,诸如Vth、Igss等。在淀积工艺中,要重点控制沉积速率、炉管清洁周期,防止产生沟槽内多晶膜层出现缝隙以及沟槽外多晶层出现凸起。在回蚀工序,要重点控制刻蚀反应物,防止造成多晶残留。清洗工序,通过选择不含水分的溶剂,避免大量水痕缺陷的产生。     

基于最佳鉴别准则的目标识别方法

讨论了使用最佳鉴别准则作为特征提取的方法识别飞机的问题。在介绍最佳鉴别集求法之后,通过计算距离可分性测度得出该方法比一般的Ｋ－Ｌ变换提取特征具有更好的可分性;最后用模糊ＡＲＴＭＡＰ神经网络作为分分类器以处理后的数据进行识别。对某相控阵雷达所得到的三类过航飞机的数据识别结果表明,该方法可以得到更高的识别率。     

使用粒子群算法进行特征选择及对支持向量机参数的优化

特征选取和参数设置是提升支持向量机分类器的效果的两个主要手段.为了将两者结合起来,实现同步优化,以达到更好的分类效果,设计了一种基于粒子群算法的分类器优化算法.新算法对粒子采用2进制编码的,设计适合的目标函数,同步进行特征选择和支持向量机参数的优化.经过对比验证,新方法能够更加准确的得到待分类数据的特征子集跟支持向量机参数,最终得到更优的处理结果.