基于自适应模板更新与多特征融合的视频目标分割算法

针对SiamMask不能很好地适应目标外观变化,特征信息利用不足导致生成掩码较为粗糙等问题,本文提出一种基于自适应模板更新与多特征融合的视频目标分割算法。首先,算法利用每一帧的分割结果对模板进行自适应更新;其次,使用混合池化模块对主干网络第四阶段提取的特征进行增强,将增强后的特征与粗略掩码进行融合;最后,使用特征融合模块对粗略掩码进行逐阶段细化,该模块能够对拼接后的特征进行有效的加权组合。实验结果表明,与SiamMask相比,本文算法性能有明显提升。在DAVIS2016数据集上,本文算法的区域相似度和轮廓相似度分别为0.727和0.696,比基准算法提升了1.0%和1.8%,速度达到40.2 f/s;在DAVIS2017数据集上,本文算法的区域相似度和轮廓相似度分别为0.567和0.615,比基准算法提升了2.4%和3.0%,速度达到42.6 f/s。     

Bandwidth-Efficient Transmission Method for User View-Oriented Video Services

The trend in video viewing has been evolving beyond simply providing a multiview option. Recently, a function that allows selection and viewing of a clip from a multiview service that captures a specific range or object has been added. In particular, the freeview service is an extended concept of multi-view and provides a freer viewpoint. However, since numerous videos and additional data are required for its construction, all of the clips constituting the content cannot be simultaneously provided. Only certain clips are selected and provided to the user. If the video is not the preferred video, change request is made, and a delay occurs during retransmission from the server. Delays due to frequent rerequests degrade the overall quality of service. For free-view services, selectively transmitting the video according to the user’s desired viewpoint and region of interest within the limited network of available videos is important. In this study, we propose a method of screening and providing the correct video based on objects in the contents. Based on the method of recognizing the object in each clip, we designed a method of setting its priority based on information about the object’s location for each viewpoint. During the transmission and receiving process using this information, the selected video can be rapidly recognized and changed. Herein, we present a service system configuration method and propose video selection examples for free-view services.     

基于运动一致性的视频对象分割方法研究

视频运动对象检测和分割是图像处理中最具挑战性的问题之一。针对目前大部分分割算法相当复杂而且计算量大的问题，提出了一种基于运动一致性的视频对象分割方法。该方法从MPEG压缩码流中提取运动矢量场来分割视频对象，首先对运动矢量场进行滤波和校正，然后进行全局运动补偿得到对象的绝对运动矢量场，最后采用K-means聚类算法对运动矢量场进行聚类分析从而分割出感兴趣的视频运动对象。MPEG标准测试序列的试验结果证明，该方法是有效的。     

基于VBR视频的联合信源信道码率控制方法

VBR视频编码与传输相比于CBR具有更大的优势。VBR编码中,需要根据编解码缓冲区和网络的约束进行信源信道码率控制。本文将联合信源信道码率选择问题进行简化,针对最新的视频压缩标准H．264提出准确的码率模型,在此模型下进行VBR信源编码码率控制,并根据缓)中器状态进行信道传输速率选择来获得平滑的网络流量。实验结果表明,这种VBR码率控制方法比CBR可以获得更高和更平稳的视频质量,而且在场景切换时效果更明显。     

基于跨时空域相似邻接图的视频分割算法

视频分割是视频处理领域的基本问题,也是该领域的研究前沿和热点问题之一,在视频监控、编辑合成等方面都有着重要的应用。传统的视频分割方法大多依赖帧间局部相似性或运动的连续性进行区域划分,对遮挡、大幅度运动等情况的分割效果较差,需要大量的手工交互。论文通过在视频空间建立跨时空域的相似性邻接关系,提出一种新的视频分割图分割模型,并且采用最大流/最小割算法对相应的模型进行快速求解,从而实现视频的有效分割。论文算法只需要用户在视频的关键帧图像上进行少量交互,便自动获取整个视频分割结果;并且,该分割过程不受前景对象遮挡、快速运动等情况的影响,具有很好的稳定性。     

一种HDTV视频编码器码率分配策略

以场景切换检测和I帧场景复杂度为依据 ,提出了一种适合基于子图划分HDTV的联合码率分配策略。实验表明 :该策略能很好地保证子图重建质量和HDTV各个子图之间主观重建质量的一致性 ,消除可能出现的子图划分效应。     

Assessment of an Engineering Ethics Video: Incident at Morales

A new engineering ethics video, Incident at Morales, was assessed with two different instruments: the standard Defining Issues Test and a short ad hoc survey. According to pre‐tests and post‐tests with the Defining Issues Test, viewers of the video increased the sophistication of their moral reasoning skills. According to the survey, viewers changed their opinions about the most important responsibilities of engineers and about meeting environmental regulations when working overseas. From these results, it appears that the video is an effective approach to teach engineering ethics.     

An object oriented implementation of a front tracking finite element method for directional solidification processes

This paper focuses on the numerical simulation of phase‐change processes using a moving finite element technique. In particular, directional solidification and melting processes for pure materials and binary alloys are studied. The melt is modelled as a Boussinesq fluid and the transient Navier–Stokes equations are solved simultaneously with the transient heat and mass transport equations as well as the Stefan condition. The various streamline‐upwind/Petrov–Galerkin‐based FEM simulators developed for the heat, flow and mass transport subproblems are reviewed. The use of classes, virtual functions and smart pointers to represent and link the particular simulators in order to model a phase change process is discussed. The freezing front is modelled using a spline interpolation, while the mesh motion is defined from the freezing front motion using a transfinite mapping technique. Various two‐ and three‐dimensional numerical tests are analysed and discussed to demonstrate the efficiency of the proposed techniques. Copyright © 1999 John Wiley & Sons, Ltd.     

Large-scale three-dimensional object measurement: a practical coordinate mapping and image data-patching method

In a practical three-dimensional (3-D) sensing system, the measurement of a large-scale object cannot be completed in only one operation. A relieflike object is generally divided into several subregions, an optical sensor positioned at each of these locations, and the shape of the whole object obtained by patching together all the 3-D data of the subregions. It is important to have accurate 3-D coordinates (x, y, z) for each subregion. We propose a new phase-to-height mapping algorithm and an accurate lateral coordinate calibration method with which to obtain the 3-D coordinates. After all the subregions are measured, it is necessary to transform the local coordinates into global world coordinates; here we present a new image data-patching method based on a flood algorithm. This method provides the optimal path along which to patch all the subregions into the shape of the entire object. We have measured and successfully patched a large sandy pool (9 m x 5 m), and the reliability and feasibility of our method have been demonstrated by experiment.     

Fast method to compute scattering by a buried object under a randomly rough surface: PILE combined with FB-SA

A fast, exact numerical method based on the method of moments (MM) is developed to calculate the scattering from an object below a randomly rough surface. Déchamps et al. [J. Opt. Soc. Am. A23, 359 (2006)] have recently developed the PILE (propagation-inside-layer expansion) method for a stack of two one-dimensional rough interfaces separating homogeneous media. From the inversion of the impedance matrix by block (in which two impedance matrices of each interface and two coupling matrices are involved), this method allows one to calculate separately and exactly the multiple-scattering contributions inside the layer in which the inverses of the impedance matrices of each interface are involved. Our purpose here is to apply this method for an object below a rough surface. In addition, to invert a matrix of large size, the forward-backward spectral acceleration (FB-SA) approach of complexity O(N) (N is the number of unknowns on the interface) proposed by Chou and Johnson [Radio Sci.33, 1277 (1998)] is applied. The new method, PILE combined with FB-SA, is tested on perfectly conducting circular and elliptic cylinders located below a dielectric rough interface obeying a Gaussian process with Gaussian and exponential height autocorrelation functions.     

Method of determining the systematic variation of the frequency of a driving oscillator situated on a moving object

A new approach to the determination of the systematic variation in the frequency of onboard time and frequency standards located on intermediate-altitude space vehicles is considered.Translated from Izmeritelnaya Tekhnika, No. 10, pp. 27–30, October, 2004.     

Reconstruction of an object from its noisy Fourier modulus: ideal estimate of the object to be reconstructed and a method that attempts to find that estimate

In general, the problem of reconstructing an object from its Fourier modulus has no solution when the Fourier modulus is contaminated by noise. Therefore a quasi solution, which we call the ideal estimate of the object to be reconstructed, is defined here based on the concept of territories of the convergence objects of the error-reduction algorithm, and a method that attempts to find that solution is presented. Keeping in mind that the ideal estimate is one of the output-stagnation objects of the hybrid input-output algorithm, we modify the hybrid input-output algorithm so that the output-stagnation objects can be located even when the value of the feedback parameter is not infinitesimally small, and this modified algorithm is combined with the hybrid input-output algorithm itself. The results of computer simulations carried out to test the performance of the proposed method are shown.     

Wavelet array decomposition of images using a Hermite sieve

Generalized Hermite polynomials are used in a novel way to arrive at a multi-layered representation of images. This representation, which is centred on the creation of a new class ofwavelet arrays, is (i) distinct from what we find in the current literature, (ii) stable, and (iii) in the manner of standard transforms, transforms the image, explicitly, into matrices of coefficients, reminiscent of Fourier series,but at various scales, controlled by ascale parameter. Among the other properties of the wavelet arrays, (a) the shape of the resolution cell in the ‘phase-space’ is variable even at a specified scale, depending on the nature of the signal under consideration; and (b) a systematic procedure is given for extracting the zero-crossings from the coefficients at various scales. This representation has been successfully applied to both synthetic and natural images, including textures.     

Questioning the assumptions: the role of vulnerability assessments in climate change adaptation

A number of challenges prevent climate change adaptation activities from contributing to vulnerability reduction. Some of these relate to the nature and quality of vulnerability assessments, while others concern how well assessments link with adaptation actions. By highlighting four persistent assumptions about the role of vulnerability assessments in adaptation, this paper seeks to identify ways in which the practice of vulnerability assessment can better support progressive adaptation actions. This paper argues that, for adaptation actions identified within vulnerability assessments to be successful, there is a need for assessment to: (i) engage with marginalized perspectives; (ii) draw upon diverse knowledge domains; (iii) integrate scales of analysis with appropriate scales of action; and (iv) build political will. This requires vulnerability assessment to be considered as more than just a method for information generation on who is most vulnerable to climate change, where they are located and the underlying reasons for their vulnerability. In addition, improving the rigor and transparency of assessments and engagement with stakeholders during the assessment process can better facilitate vulnerability-focused adaptation.     

Fast numerical method for electromagnetic scattering from an object above a large-scale layered rough surface at large incident angle: vertical polarization

A fast numerical method has been proposed in this paper for calculating the electromagnetic scattering from a perfectly electric conducting object above a two-layered dielectric rough surface. The focus in this study is large incidence. The parallel fast multipole method is combined with the method of moments for fast implementation of the scattering from this composite model. The biconjugate gradient method is adopted to solve the unsymmetrical matrix equation and parallelized. The simulating time and parallel speedup ratio with different processors are provided. Several numerical results are shown and analyzed to discuss the influences of the parameters of the rough surface, the object, and the intermediate medium on the bistatic scattering.     

Designing Nanofluidic Diode from a Hybrid-Bilayer Covalent Organic Framework: Molecular Simulation Investigation

Nanofluidic diodes are potentially useful in many important applications such as sensing, electronics, and energy conversion. However, the manufacturing of controllable nanopores for nanofluidic diodes is technically challenging. Herein, a nanofluidic diode is designed from a highly programmatic covalent organic framework (COF). Through molecular simulation, remarkable diode behavior is observed in a hybrid-bilayer COF but not in its constituent single-layer COFs. The rectification effect of ion current in the hybrid-bilayer COF is attributed to an asymmetric electrostatic potential across the COF nanopore. Furthermore, a synergistic effect of counterion is unraveled in the hybrid-bilayer COF, and the presence of counterion is found to reduce the entry barrier and facilitate ion transport. The performance of the hybrid-bilayer COF as a nanofluidic diode is comprehensively investigated by varying salt concentration, layer number, interlayer spacing, and slipping. This proof-of-concept simulation study demonstrates the feasibility of the hybrid-bilayer COF as a nanofluidic diode and the finding may stimulate the development of new nanofluidic platforms.     

Development and validation of an instrument to evaluate the content effectiveness of video games: a pilot study

Storytelling is the key design element in game design. Content preparation, which examines ‘what information users want’, yielded valuable data concerning the necessary attributes of storytelling in a web-based interface. After identifying 17 basic components of video games, the authors of this paper were able to categorise the components based on guidelines reported from the literature review into four major factors: game play; game setup; game control; and game help. In order to evaluate these factors, an experiment was conducted that required participants to evaluate three PC games selected for their distinctiveness and popularity: Need for Speed VII: Most Wanted; StarCraft; and Diablo II. Twelve highly skilled video game players were selected as participants. After playing each game, participants were asked to complete a 56-question survey and the results of a multiple regression analysis revealed that all items of development and content preparation are not of equal importance. Fantasy, pressure, reward/bonus, next step, pressure, status, menu, goal, character, hints and instruction are the components that have the most significant impact on user satisfaction.     

基于混合模型的超大规模隧道结构非线性动态有限元分析

提出了一种用于对超大规模隧道结构进行有限元分析的混合模型建模方法,弥补了以往仿真计算中宏观与微观不能同时兼顾的不足。利用并行算法,并对整体混合模型的计算时间步进行了有效的控制,使超级计算机能完成此类超大规模整体混合模型的计算。用混合模型建模法对青草沙水源地原水工程输水隧道进行非线性动态有限元仿真,得到的结果既反映了宏观的响应规律,又反映了局部精细结构的具体变化,证明了此种混合模型建模方法的可行性。     

浅谈小型空分设备间断停车后快速出氧的方法

在KDON-400/1000型空分设备因故障临时停车前、停车中及重新启动时采取了一系列优化操作,缩短了空分设备间断停车再开车的出氧时间,满足用氧需求。