靶场仿真中分布式异构网关技术研究

为快速、高效地实现试验与训练领域各靶场、设施和仿真的互操作、重用和可组合,构建实物的、虚拟的、构造的(LVC)分布式网络,研究了目前主要存在的高级分布式仿真架构,包括分布式交互仿真(DIS)、高层体系架构(HLA)及试验与训练使能体系结构(TENA);在对它们的异同进行分析比较的基础上,确定以TENA网关对异构靶场进行无缝连接是实现靶场互联的最佳方案;对网关进行了总体设计并对关键技术进行了分析,网关原型的建立为网关的深入研究和开发奠定了基础。     

动态偏置射频宽带功放设计

射频宽带功率放大器是目前功率放大器的主要发展趋势。为了提高射频宽带功率放大器的增益平坦度与效率,采用推挽结构LDmos晶体管,使用ADS软件对动态偏置电路和匹配电路进行仿真设计。详细介绍了动态偏置功率放大器的工作原理及其实现方法。实现了多倍频程带宽、确保带内增益平坦、提高功率附加效率。仿真结果表明该功率放大器对于100MHz~400MHz的信号,在整个输入功率变化范围内,功率附加效率（PAE）与传统的功放相比提高了5~15%左右。     

嵌入式软件测试的数据获取技术

测试数据获取是嵌入式软件测试的关键技术,其准确性.实时性和可靠性对测试质量有决定性影响.嵌入式软件测试需要根据软件特性和测试要求对数据获取方法进行定制设计.针对侵入式的软件插桩测试技术,着重研究了硬件采集、硬件收发、纯软件方式的插桩实现过程.对非侵入式的边界扫描技术和虚拟仿真技术的数据获取原理进行了分析,并提出了嵌入式开发测试一体化集成应用和全生存周期嵌入式软件开发,测试与管理的思想,指出了嵌入式软件测试的新方向.     

Sorcery: Overcoming deceptive votes in P2P content sharing systems

Deceptive voting behaviors of malicious users are known as the main reason of causing content pollution in Peer-to-Peer (P2P) content sharing systems. Due to the nature of P2P overlay network such as self-organization and anonymity, the existing methods on identifying deceptive votes are not effective, especially for collusive attackers. This paper presents Sorcery, a novel active challenge-response mechanism based on the notion that one side of interaction with the dominant information can detect whether the other side is telling a lie. To make each client obtain the dominant information, our approach introduces the social network to the P2P content sharing system; therefore, clients can establish the friend-relationships with the users who are either acquaintances in reality or those reliable online friends. Using the confidential voting histories of friends as own dominant information, the client challenges target content providers with the overlapping votes of both his friends and the target content provider, thus detecting whether the content provider is a deceptive user. Moreover, Sorcery provides the punishment mechanism which can reduce the impact brought by deceptive voting behaviors, and our work also discusses some key practical issues. The experimental results illustrate that Sorcery can effectively overcome the problem of deceptive voting behaviors in P2P content sharing systems, and work better than the existing reputation models.     

微电子器件温度分布测试技术研究

为改善微电子器件性能,提高可靠性,确定筛选、考核条件等都必须对器件的结温、表面温度分布以及热斑等热特性进行精确测量,红外热像法是当前测量微电子器件热特性最有效的方法之一。文章针对InfrascopeⅡ型显微红外热像仪在实际应用中如何提高其测温准确度和一致性等问题进行了研究,重点分析了样品发射率、背景环境和大气衰减等因素的影响,并给出验证解决方案,取得了满意的结果。     

Exploiting effective features for chinese sentiment classification

Features play a fundamental role in sentiment classification. How to effectively select different types of features to improve sentiment classification performance is the primary topic of this paper. Ngram features are commonly employed in text classification tasks; in this paper, sentiment-words, substrings, substring-groups, and key-substring-groups, which have never been considered in sentiment classification area before, are also extracted as features. The extracted features are then compared and analyzed. To demonstrate generality, we use two authoritative Chinese data sets in different domains to conduct our experiments. Our statistical analysis of the experimental results indicate the following: (1) different types of features possess different discriminative capabilities in Chinese sentiment classification; (2) character bigram features perform the best among the Ngram features; (3) substring-group features have greater potential to improve the performance of sentiment classification by combining substrings of different lengths; (4) sentiment words or phrases extracted from existing sentiment lexicons are not effective for sentiment classification; (5) effective features are usually at varying lengths rather than fixed lengths.     

Global sampled-data output feedback stabilisation for a class of nonlinear systems with unknown output function

This paper discusses the problem of global sampled-data output feedback stabilisation for a class of nonlinear systems whose output function is unknown. A systematic design scheme is developed to construct a linear output feedback control law in sampled-data form. An explicit formula for the maximum allowable sampling period is computed to guarantee global stability of the uncertain nonlinear systems under the proposed controller with appropriate gains. Two examples are given to demonstrate the effectiveness of the proposed design procedure.     

Global finite-time stabilization for a class of switched nonlinear systems via output feedback

This paper addresses the problem of global finite-time stabilization for a class of uncertain switched nonlinear systems via output feedback under arbitrary switchings. Based on the adding a power integrator approach, we design a homogeneous observer and controller for the nominal switched system without the perturbing nonlinearities. Then, a scaling gain is introduced into the proposed output feedback stabilizer to implement global finite-time stability of the closed-loop system. In addition, the proposed approach can be also extended to a class of switched nonlinear systems with upper-triangular growth condition. Two examples are given to illustrate the effectiveness of the proposed method.     

The Ground Process Segment of SAR Altimeter

The key innovation technology of SAR Altimeter (Synthetic Aperture Radar Altimeter)are Doppler\|beam sharpen and delay/Doppler range compensation.The cooperation of these two technologies makes it has high along track resolution and high precision in height measurement.The ground processor is the key hinge to make sure that SAR altimeter could obtain these superiorities.Many key technologies for SAR altimeter processor,such as Doppler beam\|sharpen,delay/Doppler compensation and the second range correction,multilook,echo model and gradient function for retracker,are introduced in the paper.Based on the processor and related work,some simulation work and airborne experiment were tested by the processor,and both of the quantity results show that the SAR altimeter has more potential superiorities.     

面向手持式3维扫描设备的本征纹理重建

目的 针对目前手持式3维扫描设备生成的模型纹理分辨率不够,且部分区域存在高光、阴影及明暗变化等问题,提出一种基于多幅实拍照片的纹理重建方法。方法 首先使用基于特征匹配的方法将照片图像与几何模型进行配准;其次根据重建纹理大小,采用特殊编码方式的位置纹理建立照片像素到纹理像素直接且精确的对应关系;然后根据多幅使用闪光灯作为光源拍摄的照片,通过位置纹理建立联立方程,求解漫反射分量;最后采用改进的基于混合权重的融合方法对求解的漫反射分量进行纹理融合。结果 使用本文方法对3个实验模型进行本征纹理重建,与3维扫描设备生成纹理和直接用照片生成纹理相比,该方法操作简单、使用方便,可获得高度清晰的,不含高光和明暗效果的本征纹理图像。结论 实验结果表明,重建纹理质量在分辨率、色彩还原性及一致性方面明显优于原有纹理,且该方法具有很高的精确性和鲁棒性,可满足高质量的纹理重建需求。