控制点地震前后稳定性研究方法探讨

通过对某项目连续观测数据进行精密处理,对基线向量变化进行定性、定量及统计分析,研究各控制点在地震前后稳定性变化规律,探索稳定性分析方法,确保项目的顺利开展。     

共聚乳液型高速卷烟用胶粘剂的研制

采用乳液共聚和复合乳化技术合成乳液型高速卷烟胶粘剂。产品具有初粘性好，干燥快，稳定性高等特点。     

A source coding scheme for authenticating audio signal with capability of self-recovery and anti-synchronization counterfeiting attack

Authenticating the veracity and integrity of digital media content is the most important application of fragile watermarking technique. Recently, fragile watermarking schemes for digital audio signals are developed to not only detect the malicious falsification, but also recover the tampered audio content. However, they are fragile against synchronization counterfeiting attack, which greatly narrows the applicability of audio watermarking schemes. In this paper, a novel source coding scheme for authenticating audio signal based on set partitioning in hierarchical trees (SPIHT) encoding and chaotic dynamical system with capability of self-recovery and anti-synchronization counterfeiting attack is proposed. For self-recovery feature, the compressed version of audio signal generated by SPIHT source coding and protected against maliciously tampering by repeated coding is embedded into the original audio signal. Besides, for robustness against synchronization counterfeiting attack feature, based on the position and content of audio section, check bits are generated by Hash algorithm and chaotic sequence, and taken as part of fragile watermark. Simulation results show the self-embedding audio authentication scheme is recoverable with proper audio quality, and it has capability against synchronization counterfeiting attack.

     

A novel vibration modeling method for a rotating blade with breathing cracks

This paper proposes a vibration modeling method for a rotating blade with breathing cracks, considering the coupling of the centrifugal effects, the breathing effects and the crack effects. Firstly, considering the combined effects of the centrifugal stress and the bending stress, a crack breathing model for the rotating blade is proposed. Since the crack surface cannot provide the spanwise centrifugal tensile stress, an additional bending moment will be generated at the crack surface in the rotating state.Therefore, an additional bending moment caused by the centrifugal stress is then constructed. In addition, due to the discontinuity of the crack cross section, the additional stiffness caused by the centrifugal effects of the cracked blade will be smaller than that of the normal blade. Therefore, a correction coefficient of the centrifugal stiffness is built. Furthermore, based on the Lagrange equation and the assumed modal method, the vibration equation of the rotating blade with a breathing crack is established(RBC model), and a strategy is constructed for solving this vibration equation. Finally, taking the finite element model(FEM) as a reference, the vibration responses of the RBC model, the open crack model(OC) and the bilinear crack model(BC) are compared. The necessity of the RBC model is illustrated, and the accuracy of the RBC model is verified. The RBC model is a computationally efficient alternative to the finite element analysis for the rotating cracked blade. It can provide an important tool for the vibration modeling and the vibration analysis of the rotating shaft-disk-blade system with cracked blades.     

指纹图像预处理算法

介绍并实现了一套完整的指纹图像预处理算法,包括指纹图像有效区域提取、方向图计算、方向滤波、二值化及后处理、细化等算法。实验结果表明该算法能有效地增强指纹图像,且具有较快的速度。     

双阈值法在图像边缘检测中的应用

在多尺度小波变换局部模极大值图的基础上,分别以图像边缘链的长度和按边缘链长自适应分块的块灰度作为双重阈值检测图像的边缘。实验表明,采用这一方法,可获得单像素宽、定位精准、抗噪声效果好的边缘图像。     

生物信息学中的计算机技术应用

在跟踪了当前生物信息学发展的基础上，对生物信息学中的计算机技术应用进行分析，提炼出不同的计算机技术在生物信息学科中的不同作用，以让更多的同行对这方面有所认识并在选题上有所借鉴。文中采用由点到面的方法，得出了高性能的计算机体系和网络技术是生物信息学赖以生存和发展的生命线；数据库技术是生物信息学大厦的支柱；可视化技术是生物信息学研究的重要手段；人工智能以及神经网络技术是生物信息学得以发展的保障等结论。     

Centroid-based semi-fragile audio watermarking in hybrid domain

Many previous (semi-) fragile audio watermarking schemes adopt binary images as watermarks, which reduce the security of watermarking systems. On the other hand, the content-based or feature-based second generation digital watermarking has limited applicability, and its partial feature points may be damaged by watermarking operations and various common signal processing. To overcome these problems, in this paper, a novel centroid-based semi-fragile audio watermarking scheme in hybrid domain is proposed. The...     

利用Delphi开发基于Web Services的应用系统

通过实例说明了利用Delphi开发基于Web Services的应用系统的实现方法。