一个国际产、学、研结合的范例--美国伍斯特工学院金属研究所

简要介绍美国伍斯特工学院金属研究所(MPI)在产学研结合方面的成功经验.美国伍斯特工学院是美国历史上第3所工科院校,以重视与企业合作进行工程教育而闻名.MPI是大学研究所与企业的联合体,有包括福特汽车公司、北美压铸协会等131个大大小小的企业及工业协会参加这一联合体.致力于进行针对企业存在的技术问题的基础与应用研究,开发和示范最先进的金属加工技术,为工业合伙人培训雇员等.会员自愿入会,交纳会费,由会员代表组成指导委员会,汇集和整理企业提出的技术需求,每年从中提炼出两个共性的问题,交由MPI进行研究.同时,MPI也同联合体成员共同承担美国政府资助的研究项目,这类项目多数由企业部分出资.研究工作以MPI与企业密切结合的方式开展.联合体每年举办两次会议,由MPI向企业汇报研究结果,交换信息.联合体也以伍斯特工学院为依托,开展企业的人员培训工作.     

大型异形铝铸件的铸造工艺研究

大型异形铝铸件,铸造工艺难度较大,常需依赖于丰富的生产经验辅之以计算机凝固模拟分析技术。针对不同的形状,制定相应的铸造工艺。对管体、轮毂、支腿垫块、螺旋桨等典型产品较为成熟的生产工艺进行介绍。通过对这些典型铸件的工艺案例进行分析,探讨大型异型铝铸件的铸造工艺设计方法。     

含银矿石的处理工艺技术

全面阐述国内外对含银矿石的处理工艺实践。包括①银的生产和银矿床,②银的工艺矿物学,③国外的含银矿石,④国内的含银矿石,⑤低品位银矿和尾矿中银的回收。     

铝合金支架间接挤压铸造的研究

基于有限差分法，对大型铝合金支架间接挤压铸造充型和凝固过程进行了数值模拟。通过对模拟结果的分析，确定了浇注温度为700℃，压射速度为0．03m／s，完成了模具结构和工艺设计，并制作了模具，进行了支架挤压铸造的试制。分析了试制过程铸件缺陷产生的原因，发现气孔和氧化夹渣等是主要缺陷，通过调整脱模剂的配方，适当减少脱模剂的喷涂，缩短挤压铸造循环时间等，获得了品质和性能良好的支架铸件。     

Guided Volume Editing based on Histogram Dissimilarity

Segmentation of volumetric data is an important part of many analysis pipelines, but frequently requires manual inspection and correction. While plenty of volume editing techniques exist, it remains cumbersome and errorprone for the user to find and select appropriate regions for editing. We propose an approach to improve volume editing by detecting potential segmentation defects while considering the underlying structure of the object of interest. Our method is based on a novel histogram dissimilarity measure between individual regions, derived from structural information extracted from the initial segmentation. Based on this information, our interactive system guides the user towards potential defects, provides integrated tools for their inspection, and automatically generates suggestions for their resolution. We demonstrate that our approach can reduce interaction effort and supports the user in a comprehensive investigation for high‐quality segmentations.     

基于ARM Cortex-M3的声磁商品电子防盗系统设计

针对普通EAS系统存在抗干扰性能差、检测灵敏度低、检测范围小、误报率高等缺点,设计了一种基于ARM Cortex-M3的声磁EAS系统。本文介绍了声磁EAS系统的工作原理和硬件结构框图,分析了声磁标签信号在时域和频域上的特征,提出了FFT信号频谱分析、信号互相关、最小二乘法拟合直线求取斜率、计算信号峰值数及峰值方差运算等多种检测声磁标签信号的算法,并详细描述了系统软件算法的设计。实验验证,本系统具有抗干扰性能强、检测灵敏度高、检测范围宽、误报率低等特点。     

The frequency partitioned block modified filtered-x NLMS with orthogonal correction factors for multichannel Active Noise Control

The Normalized Least Mean Square (NLMS) algorithm with a filtered-x structure (FxNLMS) is a widely used adaptive algorithm for Active Noise Control (ANC) due to its simplicity and ease of implementation. One of the major drawbacks is its slow convergence. A modified filtered-x structure (MFxNLMS) can be used to moderately improve the speed of convergence, but it does not offer a huge improvement. A greater increase in the speed of convergence can be obtained by using the MFxNLMS algorithm with orthogonal correction factors (M-OCF), but the usage of orthogonal correction factors also increases the computational complexity and limits the usage of the M-OCF in massive real-time applications. However, Graphics Processing Units (GPUs) are well known for their potential for highly parallel data processing. Therefore, GPUs seem to be a suitable platform to ameliorate this computational drawback. In this paper, we propose to derive the M-OCF algorithm to a partitioned block-based version in the frequency domain (FPM-OCF) for multichannel ANC systems in order to better exploit the parallel capabilities of the GPUs. The results show improvements in the convergence rate of the FPM-OCF algorithm in comparison to other NLMS-type algorithms and the usefulness of GPU devices for developing versatile, scalable, and low-cost multichannel ANC systems.     

Radiometric Transfer: Example‐based Radiometric Linearization of Photographs

We present an example‐based approach for radiometrically linearizing photographs that takes as input a radiometrically linear exemplar image and a target regular uncalibrated image of the same scene, possibly from a different viewpoint and/or under different lighting. The output of our method is a radiometrically linearized version of the target image. Modeling the change in appearance of a small image patch seen from a different viewpoint and/or under different lighting as a linear 1D subspace, allows us to recast radiometric transfer in a form similar to classic radiometric calibration from exposure stacks. The resulting radiometric transfer method is lightweight and easy to implement. We demonstrate the accuracy and validity of our method on a variety of scenes.     

High‐Order Recursive Filtering of Non‐Uniformly Sampled Signals for Image and Video Processing

We present a discrete‐time mathematical formulation for applying recursive digital filters to non‐uniformly sampled signals. Our solution presents several desirable features: it preserves the stability of the original filters; is well‐conditioned for low‐pass, high‐pass, and band‐pass filters alike; its cost is linear in the number of samples and is not affected by the size of the filter support. Our method is general and works with any non‐uniformly sampled signal and any recursive digital filter defined by a difference equation. Since our formulation directly uses the filter coefficients, it works out‐of‐the‐box with existing methodologies for digital filter design. We demonstrate the effectiveness of our approach by filtering non‐uniformly sampled signals in various image and video processing tasks including edge‐preserving color filtering, noise reduction, stylization, and detail enhancement. Our formulation enables, for the first time, edge‐aware evaluation of any recursive infinite impulse response digital filter (not only low‐pass), producing high‐quality filtering results in real time.