基于多小波变换及多层阈值的图像降噪研究

提出了一种基于多小波变换分层阈值的图像降噪的方法。此方法首先对一幅噪声图像进行多小波分解;接着根据多小波分解后的能量分布特性,在不同尺度的高频子带内,对小波系数进行不同阀值处理;最后经多小波反变换,得到重构图像。实验结果表明:此方法既可以有效地降低噪声,又可以较好地保持图像细节。     

Intelligent condition monitoring using fuzzy inductive learning

Extensive research has been performed for developing knowledge based intelligent monitoring systems for improving the reliability of manufacturing processes. Due to the high expense of obtaining knowledge from human experts, it is expected to develop new techniques to obtain the knowledge automatically from the collected data using data mining techniques. Inductive learning has become one of the widely used data mining methods for generating decision rules from data. In order to deal with the noise or uncertainties existing in the data collected in industrial processes and systems, this paper presents a new method using fuzzy logic techniques to improve the performance of the classical inductive learning approach. The proposed approach, in contrast to classical inductive learning method using hard cut point to discretize the continuous-valued attributes, uses soft discretization to enable the systems have less sensitivity to the uncertainties and noise. The effectiveness of the proposed approach has been illustrated in an application of monitoring the machining conditions in uncertain environment. Experimental results show that this new fuzzy inductive learning method gives improved accuracy compared with using classical inductive learning techniques.     

Visibility threshold in sharpness for people with different regional backgrounds

Abstract— The influence of regional background on the visibility of sharpness differences has been investigated by blurring various still images to different extents. The assessment of sharpness has been performed both in China by Chinese people and in the Netherlands by European people. The results showed that both Chinese characters and Roman text were clearly more critical image material for judging sharpness than natural images. Independent on whether the image contained Chinese characters or Roman text, the visibility threshold for a difference in sharpness was the same for both the Chinese and European people. When related to a diagonal step response, the threshold on average equaled an angular resolution of 5 arcsec.     

基于KELM和多传感器信息融合的风电齿轮箱故障诊断

为提高风电齿轮箱的运行效率,降低风电场的运行维护成本,结合时域统计特征分析和多传感器信息融合技术,提出了一种基于灰狼优化核极限学习机(GWO-KELM)的风电齿轮箱状态监测新方法。首先,计算原始振动信号不同的时域统计特征参数,并采用并行叠加的方式对特征级和数据级进行信息融合以得到融合数据集。其次,利用融合数据集,建立了基于GWO-KELM的故障分类识别模型。最后,运用所提方法对QPZZ-Ⅱ旋转机械振动试验台齿轮箱实测数据进行状态监测,实例结果表明了该方法的有效性和可行性,与其他同类方法相比,所提方法具有最佳分类性能。     

往复压缩机组状态监测系统开发

往复压缩机组状态监测系统的开发，主要是针对机组的运行特点和现场要求而设计的，通过对机组进行状态监测，可以实时掌握机组运行状态和变化趋势，为实现预知维修及机组的高效运行提供了可靠的保障。     

基于组态思想的压缩机组网络工况监测与远程诊断系统开发

提出一种新型的基于组态化思想的压缩机组网络工况监测与远程故障诊断系统。该系统以组态化网络监视与诊断系统管理平台的Web服务器为核心，加上多台工控机和普通计算机组成。用户在远程的浏览器上方便地控制和管理现场工控机，组建网络在线实时监视子系统、数据分析了系统和远程诊断子系统。论述系统的总体方案，现场监视子系统、数据传输管理软件、网络监视与诊断子系统以及系统管理平台的设计，阐述系统组态构建过程、最后给出系统在现场实际应用的例子。     

奥氏体不锈钢搪玻璃反应釜的研制和应用

用奥氏体不锈钢作为搪玻璃反应釜的受压元件基体和设计的专用底釉 ,经特定的搪烧工艺方法制成在一定的低温工况 (≥ - 40℃～≤ - 2 0℃ )下能安全运行的不锈钢搪玻璃反应釜。该设备的推广应用对促进我国生物工程、医药化工、有机高分子等行业的发展起到积极作用。     

管线钢氢致断裂门槛应力与氢渗透的相关性

用电化学和恒载荷拉伸试验方法，测定了不同充氢电流下氢在X80管线钢中的扩散系数、试样中可扩散氢浓度以及管线钢氢致断裂门槛应力。结果表明，X80管线钢在0．5mol／LH2SO4 0．25g／LAs2O3溶液中充氢时，试样中可扩散氢浓度(C0)与充氢电流的方根（√i)呈线性关系；恒载荷下氢致断裂门槛应力(σHIC)随氢浓度的对数(1nC0)而线性下降。     

联合收获机谷物状态监测装置采样盒及其减振器

联合收获机的作业参数与作业性能密切相关,为了满足联合收获机作业性能的实时监测需求,设计了谷物状态监测装置采样盒及其减振器。采用动力学原理分析了联合收获机作业过程中阻流阀往复运动的“采样-卸样”动作特性;运用能量守恒原理建立了有约束条件的减振器保守系统动力学模型;利用多体动力学分析软件ADAMS建立了减振器动力学模型的虚拟样机并进行了求解,通过田间试验验证了该装置的可行性。对比无减振器作业情况,有减振器时谷物状态监测装置获取的图像中籽粒和杂质边缘清晰,图像质量更高;在同样的图像处理算法下,有减振器时破碎率监测结果精度提升了13.7%,监测精度达到了81.3%,含杂率监测结果精度提升了33.6%,精度达到了86.0%。     

Contact and friction between catheter and blood vessel

Therapeutic vascular catheterization techniques are sometimes hampered by the frictional forces between the blood vessel and the catheter, when contact points of the vessel are changing and deforming during the movement of the catheter. The goal of the present study was to characterize frictional interactions between the blood vessel wall and the catheter using experimental and numerical analysis. First, the frictional force was measured with an experimental apparatus that uses a ball and flattened porcine aorta to simulate frictional forces between the catheter and the vessel. Second, catheter motion was characterized by two-dimensional numerical calculations based on the experimental results. Experimental analysis demonstrated that slip occurred and that friction coefficient between the vessel and the catheter and the deformation of the specimen were small when the contact between the ball and the aorta occurred at a small angle. The compliance of the specimen in the normal direction obtained by the experiment was by far larger than that calculated according to the Hertzian contact theory. Numerical analysis shows that this difference of the parameter of the vessel, which must be determined accurately in surgical simulator, could affect the trajectory of the catheter.