基于CORBA的移动多Agent框架

随着网络和移动智能体技术的不断发展,如何在网络资源中找到自己需要的服务成为一个热门话题。描述以一种移动的多智能体系统,并且在进行系统底层通信、智能体在网络环境移动、智能体与服务器之间通信应用CORBA。服务器接受任务,派遣服务请求智能体在网络环境中寻找能为自己提供服务的服务器,完成向服务器预订服务任务。给出系统接受任务后派遣请求智能体的工作流程及服务器接受智能体访问的流程。     

MPEG-2/4 AAC 音频编码器实时性能优化研究进展

目前,MPEG-2/4 AAC已成为广泛使用的一种音频编码压缩标准,但是MPEG-2/4 AAC标准的音频编码器存在算法复杂度高、计算量和时闻延迟大等缺点,无法满足实时性要求.从MPEG-2/4 AAC音频编码器的内部结构入手,分析了制约其实时性能的主要环节,就心理声学模型、滤波器组、量化与编码模块3个部分,归纳了当前MPEG-2/4 AAC实时音频编码器实现与优化研究的相关内容和进展,给出了若干算法的主要思想、改进结果和优缺点.在此基础上,提出了进一步优化MPEG-2/4 AAC实时性能的研究方向,以及需要解决的主要问题.     

红外探测系统计算机仿真模型研究

从红外系统的探测原理出发,通过分析红外探测系统中各子模块的物理效应对目标探测的影响,对不同物理效应进行建模,构建了一套红外探测系统计算机仿真模型。通过仿真试验,验证了模型的正确性。     

一种新型CMOS电流反馈运算放大器的分析与设计

通过加入对电源电压不灵敏的基准源产生偏置电流,采用MOS管产生的电阻和MOS管电容串联的补偿结构,消除补偿电容带来的零点;并在输出端采用电阻反馈,降低了输出电阻,增强了带负载能力.在1.5 V电压下,偏置约为1 μA.基于BSM3 0.5 μm CMOS工艺,对电路进行了PSPICE仿真.负载为20 pF时,该电路获得了87 dB的开环增益,353 MHz的单位增益带宽,61°的相位裕度和132 dB的共模抑制比,功耗为1.24 mW.     

有限域上超椭圆曲线离散对数问题的错误攻击

In this paper, we present two explicit inva-lid-curve attacks on the genus 2 hyperelliptic curve o-ver a finite field. First, we propose two explicit attack models by injecting a one-bit fault in a given divisor. Then, we discuss the construction of an invalid curve based on the faulted divisor. Our attacks are based on the fact that the Hyperelliptic Curve Scalar Multiplica-tion (HECSM) algorithm does not utilize the curve parameters and We consider three hyperelliptic curves as the attack targets. For curve with security level 186 (in bits), our attack method can get the weakest inva-lid curve with security level 42 (in bits); there are 93 invalid curves with security level less than 50. We al-so estimate the theoretical probability of getting a weak hyperelliptic curve whose cardinality is a smooth integer. Finally, we show that the complexity of the fault attack is subexponential if the attacker can freely inject a fault in the input divisor. Cryptosystems based on the genus 2 hyperelliptic curves cannot work against our attack algorithm in practice.     

Novel 4-(2,2-diphenyl-vinyl)-phenyl substituted pyrene derivatives as efficient emitters for organic light-emitting diodes

Two pyrene derivatives (PVPP and TPVPP) bearing 4-(2,2-diphenyl-vinyl)-phenyl side unit were developed for organic light-emitting diodes. Their photophysical, thermal, electrochemical, and electroluminescent properties as well as the film morphologies have been investigated in detail. Both of them exhibit high solid-state quantum yields, good thermal stability, and high glass-transition temperatures in the range of 127–150 °C. In particular, it is found that multiple side units can significantly affect the electrochemical properties to improve the electron injection. The LUMO energy level of TPVPP is −2.76 eV, which is very close to that of commonly used electron transport materials. The maximum luminance of OLED devices using TPVPP as an emitter layer is 103835 cd/m² with a maximum current efficiency of 5.19 cd/A and a maximum power efficiency of 3.38 lm/W.     

Restoration of embedded image from corrupted stego image

Digital images are easily corrupted by noise during transmission. This paper presents a robust method for restoring embedded image from corrupted stego image. We firstly identify unreliable bits of each pixel in the embedded image by detecting noise in the stego image. Secondly, we calculate the distortion value and credibility value of each pixel, and use them to determine corrupted pixels. For each corrupted pixel, we correct its value by adjusting the unreliable bits. Experimental results show that the proposed method can restore embedded image with good visual quality.     

雷达红外诱饵弹对抗反辐射导弹技术研究

针对雷达电磁诱饵不能诱偏加装红外制导导引头反辐射导弹的问题,提出了雷达红外诱饵弹对抗反辐射导弹的方法,分析了雷达红外诱饵弹的工作原理,建立了红外诱饵弹对抗反辐射导弹的效能模型,仿真分析了不同条件下的效能模型,对红外诱饵弹在实际中的运用有一定的指导意义。     

OFDMA感知无线电网络中一种基于拍卖博弈的频谱共享新算法

在基于OFDMA的感知无线电网络中,为了最大化从网络的吞吐量,考虑了空间频率复用,通过干扰判据和邻接矩阵描述感知链路在子载波上的冲突,将最大化从网络和速率的问题建模为基于VCG机制的多个赢家的子载波拍卖博弈。通过逐一求解单个子载波上的二进制整数规划问题获得最优解。仿真结果表明,所提出的子载波拍卖算法有效地提高了感知无线电网络中资源的利用效率。     

典型线面目标合成孔径雷达参数化成像

在复杂场景(特别是城区场景)合成孔径雷达(SAR)遥感成像中,存在大量线、面目标,如城区中的道路和建筑物边缘等目标,这些线面目标微波散射信号方向性强。传统SAR从单一视角获取场景的散射信息,且传统成像算法均基于点目标模型,使得传统SAR图像中线面目标主要特征表现为一系列的强散射点,而非线散射特征和面散射特征,最终造成SAR图像中目标不连续,SAR图像解译困难。因此,该文通过建立典型线段、三角面元目标的参数化回波模型,对线面目标SAR成像机理进行了深入细致的研究;并基于提出的参数化模型对线面目标进行参数化成像,即首先基于贝叶斯理论和所提的参数化模型对典型的线面目标进行分类判决,随后采用再成像的方式获得有效表征线、面目标散射特征的SAR图像,为线、面目标SAR图像解译提供有效支撑。最后,数值仿真实验成功验证了所提算法的有效性和正确性。