Local Image Features Resulting from 3-Dimensional Geometric Features,Illumination, and Movement: I

We study images of smooth or piecewise smooth objects illuminated by a single light source, with only background illumination from other sources. The objects may have geometric features (F), namely surface markings, boundary edges, creases and corners; and shade features (S), namely shade curves and cast shadow curves. We determine the local stable interactions between these and apparent contours (C) for the various configurations of F, S, C, and we concisely summarize them using an “alphabet” of local curve configurations. We further determine the generic transitions for the configurations resulting from viewer movement. These classifications are obtained using the methods of singularity theory, which allows us to ensure that our lists are complete, in some cases correcting earlier attempts at similar classifications. Authors were partially supported by Insight 2+ grant from the European Commission. J. Damon was partially supported by the National Science Foundation grants DMS-0405947 and DMS-0706941.     

个性化视频情感内容分析:综述

个性化视频情感内容分析是近几年兴起的一个研究热点,其目的是基于视频用户的个人兴趣和爱好来向其推荐个性化的视频内容。然而,当前仍然缺乏对该研究方向的最新研究进展的综述和讨论。为解决此问题,从3个方面对该领域的研究成果进行论述,讨论了各类现有方法的优缺点、存在的问题和挑战,并对未来的研究方向提出一些思路和建议。     

Impact of viewer engagement on gift-giving in live video streaming

This study investigates the effect of viewer engagement on gifting items to a streamer in a live video streaming. Data were collected from AfreecaTV, a leading live video streaming platform in South Korea, to examine viewer engagement and gift-giving behavior. After analyzing 2,294,837 viewers over a three-month period, the empirical results provide evidence that viewer engagement is positively associated with gift-giving decisions. However, the impact of viewer engagement on the amount of gifts purchased is different depending on how the engagement is measured (i.e., by stream or by channel). This study empirically proves that the motive for socialization has a high correlation with gift-giving behavior, which is considered as commoditization of a viewer’s social interaction while consuming media. The study concludes with a discussion on practical implications for live video streaming services and suggestions for future research.     

Internet-based dimensional verification system for reverse engineering processes

This paper proposes a design methodology for a Web-based collaborative system applicable to reverse engineering processes in a distributed environment. By using the developed system, design reviewers of new products are able to confirm geometric shapes, inspect dimensional information of products through measured point data, and exchange views with other design reviewers on the Web. In addition, it is applicable to verifying accuracy of production processes by manufacturing engineers. Functional requirements for designing this Web-based dimensional verification system are described in this paper. ActiveX-server architecture and OpenGL plug-in methods using ActiveX controls realize the proposed system. In the developed system, visualization and dimensional inspection of the measured point data are done directly on the Web; conversion of the point data into a CAD file or a VRML form is unnecessary. Dimensional verification results and design modification ideas are uploaded to markups and/or XML files during collaboration processes. Collaborators review the markup results created by others to produce a good design result on the Web. The use of XML files allows information sharing on the Web to be independent of the platform of the developed system. It is possible to diversify the information sharing capability among design collaborators. Validity and effectiveness of the developed system has been confirmed by case studies.     

PDM系统三维浏览器的研究与开发

从PDM读取和管理产品以及生产过程的三维信息的重要性出发，分析了开发三维浏览器的必要性；通过对DXF文件的分析，提出了采用SQLServer数据库来存储DXF的几何信息，以供OpenGL进行三维方针的设计思路，并给出了系统的总体结构框架和设计方法。     

嵌入式系统故障诊断辅助工具ADV的设计与实现

嵌入式系统故障诊断辅助工具Advanced Data Viewer(ADV)，是用于嵌入式系统故障诊断的辅助工具。它提供了一种以用户定义的格式显示Dump Data的能力，通过对Dump Data的分析，可以有效地帮助诊断软件系统和嵌入式系统故障的原因。介绍了ADV系统数据类型定义、数据解析以及数据显示等的设计和实现。     

Gamma rate theory for causal rate control in source coding and video coding

The rate distortion function in information theory provides performance bounds for lossy source coding. However, it is not clear how to causally encode a Gaussian sequence under rate constraints while achieving R–D optimality. This problem has significant implications in the design of rate control for video communication. To address this problem, we take distortion fluctuation into account and develop a new theory, called gamma rate theory, to quantify the trade-off between rate and distortion fluctuation. The gamma rate theory implies that, to evaluate the performance of causal rate controls in source coding, the traditional R–D metric needs to be replaced by a new GRD metric. The gamma rate theory identifies the trade-off between quality fluctuation and bandwidth, which is not known previously. To validate the gamma rate theory, we design a rate control algorithm for video coding; our experimental results demonstrate the utility of the gamma rate theory in video coding.     

The oberon system

In this paper we describe an operating system for a workstation designed and implemented by the authors within two and a half years. It includes memory management and module loader, a file system, a viewer system, editors for text and graphics, a compiler, a server interface and various tools. The primary motivation was to demonstrate the feasibility of a small, yet highly flexible and powerful, system, a system that is a (decimal) order of magnitude smaller than commonly used operating systems. This is possible due to regularity of concepts and concentration on the essential. The benefits are not only fewer resources needed, but elegance and generality of concepts resulting in transparency and convenience of use and increased reliability. A corner-stone of this approach is genuine extensibility, which is achieved by a new language, in particular by a facility called type extension. It allows for the integration of variables (objects) of a new, extended type in structures of elements of an existing base type.     

基于水平集函数拓扑优化设计的数字化制造实现

基于水平集函数和Lagrange乘子法实现结构拓扑优化设计,并将优化后空间三维模型的点云数据存入结构数据库.提出用空间三角形面片法逼近拓扑优化后水平集曲面,用面片边线的参数方程实现对优化结果边界的提取.基于数字化制造技朱的加工程序标准,将提取的边界点云数据变成数控机床的加工程序代码,实现数字化优化后工件的数控加工.文中算例使用线切割机床的数字化加工技术实现数字化制造.该结果真正实现了从拓扑优化设计到数字化制造的全过程,为拓扑优化设计的数字化制造奠定了基础.     

基于LTI Viewer的负反馈放大器频率补偿

为了提高负反馈放大器的稳定性,需要对负反馈放大器进行频率补偿.用Matlab中的LTI Viewer进行负反馈放大器的稳定性分析和频率补偿设计是一种非常有效的方法.本文介绍LTI Viewer进行负反馈放大器的滞后补偿、超前补偿和超前带后补偿的设计方法,对比了三种不同补偿方式的特点,给出相应的程序及结果分析.表明用LTI Viewer进行多级负反馈放大器的设计与分析,方法简便、实用,图形化特点强,且交互性好.