国际工程投标的标价优化

本文利用概率论，线性代数和效用理论来解决竞争性投标中的标价优化问题。参与投标的施工企业对以前的投标数据作概率统计，并为所选的投标指标建立效用函数，将正在投标的新项目的数据与过去的经验数据全面对照，经数据处理后计算出最高的期望标价从而达到既能中标又能最大限度地提高标价的目的。     

基于MMX技术的H.264解码器优化

新一代视频编码标准H.264为了提高编码效率采用了一系列新技术，而这些新技术的使用也极大地增加了算法的复杂度。因此，在保持编码效率的同时如何提高编解码器的运算速度成为目前研究的热点问题之一。介绍了符合H.264基本规范的解码器的基本框架和解码流程；通过复杂度分析确定了解码过程中计算最为密集的两个模块，即插值、整数余弦变换和重建模块；提出了基于MMX技术的优化方法，并对这两个模块进行了重点优化。实验结果表明，利用这些优化方法可以使解码器的平均解码速度提高到原来的1．4-2．1倍，优化效果十分显著。     

基于人类听觉的伪随机序列的信息隐藏技术

提出了一种在话音传递中，蒙蔽人类听觉的信息隐藏模型。给出了数字音频信号中信息隐藏的伪随机序列生成算法。利用此算法对隐蔽信息先加密，再对数字音频信号进行分段处理，并选出部分段做离散余弦变换(DCT)，最后依据人类的听觉系统选择DCT域中高频系数进行量化完成加密的隐蔽信息嵌入。实验结果表明，在提高鲁棒性的同时，还大大增加了安全性，就是在外界发现数字音频含有隐藏信息的情况下，在不知道密钥的情况下，还是很难提取隐蔽信息。     

MPEG2视频芯片IDCT的一种VLSI实现方案

介绍了一种2-D × 8 8 IDCT处理器系统的ASIC架构,采用分布算法、并行结构、流水线设计。对于常用的ROM查找表实现方案,该文提出了一种以寄存器、加法器构建的替代电路的新方案,同样省去了乘法器,避免了使用ROM,且硬件代价与使用ROM相比还略有减小,最终提高了数据的吞吐量,达到2.4GB/s,满足了MP@HL标准的HDTV的108MHz的频率要求,而同样工艺条件下采用ROM查找表则只能达到90MHz的频率。     

基于统计的中文文本主题自动提取研究

文本主题自动提取是一种很有实用价值的技术，它可以有效地浓缩整个web页面，解决无线网络终端由于显示屏太小而无法显示整个网页的难题。总结了目前有关文本主题提取方面的研究成果，设计了一个特征词加权函数，在此函数中考虑了词所跨的段落数因子，同时采用非线性函数描述词长因子和词所跨的段落数因子的作用，并将加权函数应用于主题自动提取。实现了一个中文主题自动提取系统原型，通过对文本集的测试验证了加权函数的有效性。     

双向渐厚综放工作面不同开采时期来压特征研究

针对焦作矿区首个综放工作面——九里山矿15081工作面的复杂开采技术条件,对其初采时期、局部放煤时期、放煤时期三个时期的基本顶来压步距与来压强度进行研究。根据理论计算和现场监测,揭示了该工作面在不同时期的来压特征:随着放煤范围的扩大,整个工作面的来压强烈程度会逐渐降低,直至基本消失;局部放煤时期与放煤时期相比,周期来压步距差距不大,来压强度较日常支架工作阻力水平略高。研究结果为矿井的安全高效绿色生产提供了理论指导与现场经验。     

Two-dimensional discrete cosine transform on sliding windows

The discrete cosine transform (DCT) has been successfully used for a wide range of applications in digital signal processing. While there are efficient algorithms for implementing the DCT, its use becomes difficult in the sliding transform scenario where the transform window is shifted one sample at a time and the transform process is repeated. In this paper, a new two-dimensional sliding DCT (2-D SDCT) algorithm is proposed for fast implementation of the DCT on 2-D sliding windows. In the proposed algorithm, the DCT coefficients of the shifted window are computed by exploiting the recursive relationship between 2-D DCT outputs of three successive windows. The theoretical analysis shows that the computational requirement of the proposed 2-D SDCT algorithm is the lowest among existing 2-D DCT algorithms. Moreover, the proposed algorithm enables independent updating of each DCT coefficient.     

A new SVM-based relevance feedback image retrieval using probabilistic feature and weighted kernel function

Relevance feedback (RF) is an effective approach to bridge the gap between low-level visual features and high-level semantic meanings in content-based image retrieval (CBIR). The support vector machine (SVM) based RF mechanisms have been used in different fields of image retrieval, but they often treat all positive and negative feedback samples equally, which will inevitably degrade the effectiveness of SVM-based RF approaches for CBIR. In fact, positive and negative feedback samples, different positive feedback samples, and different negative feedback samples all always have distinct properties. Moreover, each feedback interaction process is usually tedious and time-consuming because of complex visual features, so if too many times of iteration of feedback are asked, users may be impatient to interact with the CBIR system. To overcome the above limitations, we propose a new SVM-based RF approach using probabilistic feature and weighted kernel function in this paper. Firstly, the probabilistic features of each image are extracted by using principal components analysis (PCA) and the adapted Gaussian mixture models (AGMM) based dimension reduction, and the similarity is computed by employing Kullback–Leibler divergence. Secondly, the positive feedback samples and negative feedback samples are marked, and all feedback samples’ weight values are computed by utilizing the samples-based Relief feature weighting. Finally, the SVM kernel function is modified dynamically according to the feedback samples’ weight values. Extensive simulations on large databases show that the proposed algorithm is significantly more effective than the state-of-the-art approaches.     

直升机卫星通信系统关键技术研究

基于直升机卫星通信系统的特点,分析了卫星通信系统中姿态角提取、坐标变化及抗遮挡等关键技术,采用链路分析估算方法,提出了针对关键技术点的测试方案设计,通过工程案例验证,实现了对系统的测试与评估。     

Solitons and periodic solutions of coupled nonlinear evolution equations by using the sine–cosine method

In this paper, we establish exact solutions for coupled nonlinear evolution equations. The sine–cosine method is used to construct exact periodic and soliton solutions of coupled nonlinear evolution equations. Many new families of exact travelling wave solutions of the (2+1)-dimensional Konopelchenko–Dubrovsky equations and the coupled nonlinear Klein–Gordon and Nizhnik–Novikov–Veselov equations are successfully obtained. The obtained solutions include compactons, solitons, solitary patterns and periodic solutions. These solutions may be important and of significance for the explanation of some practical physical problems.