LiveROMS: A virtual environment for ocean numerical simulations

LiveROMS is a bootable DVD that contains an Linux-based computer operating system which has a complete, functioning version of the ROMS ocean circulation model and an Octave version of ROMSTOOLS. It allows students and scientists to experiment with this ocean numerical model, with just a basic knowledge of Linux.     

GeoPDEs: A research tool for Isogeometric Analysis of PDEs

GeoPDEs (http://geopdes.sourceforge.net) is a suite of free software tools for applications on Isogeometric Analysis (IGA). Its main focus is on providing a common framework for the implementation of the many IGA methods for the discretization of partial differential equations currently studied, mainly based on B-Splines and Non-Uniform Rational B-Splines (NURBS), while being flexible enough to allow users to implement new and more general methods with a relatively small effort. This paper presents the philosophy at the basis of the design of GeoPDEs and its relation to a quite comprehensive, abstract definition of IGA.     

Low frequency frame-wise normalization over constant-Q transform for playback speech detection

The playback speech contains information from the environment, playback and recorder used. This work focuses on proposal of a novel normalization scheme, namely, low frequency frame-wise normalization (LFFN) as one of the modules in feature extraction process that is hypothesized to help in capturing the artifacts from the playback speech. It is based on low frequency bin processing that is performed frame-wise and hence its name. The constant-Q transform (CQT) based features are found to provide the benchmark results for detection of spoofing attacks. In this work, LFFN is combined with CQT to extract two new features from octave and linear power spectra, respectively. The first one is obtained by CQT, LFFN and octave segmentation that is referred to as constant-Q normalization segmentation coefficients (CQNSC). The latter uses conventional constant-Q cepstral coefficient (CQCC) and LFFN to obtain constant-Q normalization cepstral coefficients (CQNCC). The studies are performed on ASVspoof 2017 version 2.0 corpus that is designed for studying playback speech detection. The experimental results show the effectiveness of proposed LFFN with CQT based features. We obtain equal error rate of 10.63% and 10.31% for CQNSC and CQNCC features on the evaluation set of ASVspoof 2017 version 2.0 corpus, respectively.     

基于改进MultiResUNet网络的甲状腺超声图像分割

甲状腺超声图像分割在临床超声图像研究中有很重要的意义。针对甲状腺超声图像信噪比低,斑点噪声多,且甲状腺形态不确定等问题,提出了一种改进的MultiResUNet分割网络(称为Oct-MRU-Net网络)。该方法在MultiResUNet网络的基本结构的基础上引入Octave卷积,并采用改进的Inception模块学习不同空间尺度的特征,将训练过程中的特征图按通道方向分为高低频特征。其中,高频特征描述图像细节和边缘信息,低频特征描述图像整体轮廓信息。在甲状腺超声图像分割过程中可以重点关注高频信息,减少空间冗余,从而实现对边缘更加精细的分割。实验结果表明,Oct-MRU-Net网络的性能相较于U-Net网络和MultiResUNet网络都有较大的提升,说明该网络对甲状腺超声图像的分割效果较好。     

ZB45包装机组和ZJ17卷接机组噪声分析及治理方法

为降低ZB45包装机组和ZJ17卷接机组操作位噪声,利用噪声测试设备分别对两种机器进行了噪声测试,利用得出的噪声1/3倍频程图和频谱图,对ZB45包装机组和ZJ17卷接机组的噪声特性进行了分析。结果表明,ZB45包装机组和ZJ17卷接机组的噪声能量主要集中于低、中频率范围,其操作位噪声1/3倍频程最大噪声分别位于63 Hz和125 Hz频域,噪声均超过了85 dB(A)。通过采取减弱振动噪声强度、隔离振动噪声传播途径和阻尼吸声措施,使操作位的噪声控制在85 dB(A)以下,降低了噪声对操作者的危害。     

倍频程螺旋线行波管2.5维大信号分析和设计

本文利用2.5维大信号分析程序和辅助分析程序,对一只7-18GHz带宽,2-2.5kW脉冲输出功率的螺旋线行波管进行计算机模拟,电子注感应电流基波分量在螺旋线慢波系统高频场中的相位分析和最佳工作点分析。在此基础上,探讨了色散曲线布局,衰减器配置,切断位置,再同步设计等倍频程螺旋线行波管的设计方法。     

From Carnival to Satire: Photomontage as a Commentary on Photography

This article discusses two eras of manipulated photography –that of trick photography before 1914 and that of photomontage of the 1930s. The former had a carnivalesque character, while the latter highlighted political satire. Although profusely discussed in its days, trick photography was largely anonymous. By contrast, the 1930s brought about distinct personalities such as John Heartfield or the Soviet cartoonist Boris Klinch as well as prominent theorists, including Karel Teige or Günther Anders. Despite formal differences the article argues for a continuity of approaches: both periods represent steps that question photography as a medium that claims stable signification.     

Improved traffic sign recognition algorithm based on YOLOv4-tiny

This study offers an enhanced yolov4-tiny traffic sign identification method for easy deployment on mobile or embedded devices to address the difficulties of a high number of parameters, low recognition accuracy, and poor real-time performance of traffic sign recognition models in complex scenarios. The yolov4-tiny network serves as the model’s foundation. To begin, Octave Convolution is incorporated into the backbone network to eliminate low-frequency feature redundancy, lowering the number of parameters in the model and enhancing computational efficiency. Second, the convolutional block attention module is employed to improve the recognition accuracy of small and medium-sized targets by strengthening the weights of traffic sign regions and suppressing the weights of invalid features. Finally, in the feature fusion stage, the Feature Pyramid Networks structure is replaced with the Simplified Path Aggregation Network structure to improve the fusing of shallow feature information with deep semantic knowledge and lower the miss detection rate even more On the TT100K data set as well as on CCTSDB dataset, the experimental results suggest that our technique can achieve good recognition performance. With a 16MB model size, our solution improves the mean average precision by 3.5 percent and the Frame Per Second by 12.5 f/s when compared to the yolov4-tiny algorithm. Our method outperforms yolov4-tiny in terms of recognition accuracy and detection speed, and it can easily meet the real-time requirements for traffic sign recognition.     

利用同伦法解算自然分风网络

为了解决牛顿法解算自然分风网络时对初值的依赖性,并解决利用诸如Matlab 和VB等编程语言进行风网解算时所付出的版权费用,利用自由软件Octave对解非线性方程组的常用算法——同伦法进行了讨论,论证了其在解算自然分风网络时的有效性.     

车辆相关内饰件隔吸声性能的研究

车辆室内噪声是汽车NVH的主要内容。介绍了使用full window法来评价整车内饰件中相关材料的隔吸音性能的方法,利用倍频图和Front／back图对测试所得数据进行分析,确定车辆内饰相关部分对于整车噪声的贡献量;以及通过修改相关内饰件的设计和组合来改进车内噪声,同时也为汽车制造商内饰件的开发提供方便。