电力系统非线性负荷谐波源的仿真分析

从理论上推导出电力系统中的非线性负荷在吸收系统基波功率的同时向系统发出谐波,从而成为谐波源,并从功率方向着手,根据非线性负荷的不同作用机理建立不同的仿真模型分别验证了两种不同类型的非线性负荷谐波功率流向。实验结果表明,非线性负荷使系统电压、电流发生畸变,向系统发出谐波功率,从而验证了理论分析的正确性。     

At the foundations of information justice

Is there such a thing as information justice? In this paper, I argue that the current state of the information economy, particularly as it regards information and computing technology (ICT), is unjust, conferring power disproportionately on the information-wealthy at great expense to the information-poor. As ICT becomes the primary method for accessing and manipulating information, it ought to be treated as a foundational layer of the information economy. I argue that by maximizing the liberties (freedom to use, freedom to distribute, freedom to modify, and so on) associated with certain computer software, an incentives-rich and stable environment can be established in ICT that will foster development of the information economy among the information poor. I suggest that the now-mature Free and Open Source Software paradigm, which has already produced widely-used enterprise-class applications, can be harnessed in support of these ends.     

Social networks and coordination performance of distributed software development teams

In this study, we explore the coordination performance of the geographically distributed software development teams by exploring OSS (Open Source Software) development dataset available through SourceForge.com. OSS team structures have traditionally been geographically dispersed and therefore, the coordination of post release activities such as testing efforts have been carried out by means of communication via electronic forms, such as email or message boards and forums. In our current communication-enriched environment, best practices for coordination are adopted by all software projects yet some still fail to achieve their target performance. Does team structure have any bearing on the performance outcome of the project? How does the communication between teams and their external parties affect ultimate success or failure of projects? We seek to answer above questions by applying existing theories and analytical methods from social networks for exploring the coordination performance of defect management activities found in OSS projects. We propose social networks based theoretical model for exploring distributed coordination structure and apply that for the case of OSS defect management process for exploring the structural properties, which induce the greatest coordination performance. The outcome of our suggest that there is correlation between certain network measures such as density, centrality and betweenness and coordination performance measures of defect management systems such as quality and timeliness.     

基于OpenGL的三维图形绘制和3D建模

介绍了利用OpenGL实现三维图形绘制的基本编程框架和方法,对OpenGL中光照、材质、投影等关键技术的应用方法进行了重点阐述。简要介绍了利用3D Studio Max构建复杂模型,以降低用OpenGL构造复杂模型难度、减少建模工作量的方法。     

青海三江源地区小康社会建设中的全民健身活动

通过实地调查和相关数据统计,分析了三江源地区的小康社会建设的实现程度和全民健身活动的开展情况,对三江源地区小康社会建设中的全民健身活动的发展对策进行了探讨。     

星载SAR方位压缩处理的FPGA实现

星上实时成像处理器是未来星载合成孔径雷达的重要组成部分,它可以进一步提高星载合成孔径雷达的性能,拓宽其应用。方位压缩处理是实时成像处理的核心。本文介绍了合成孔径雷达方位压缩处理的基本原理,并对星上实时成像处理器的系统参数进行了详细分析,提出了一种基于FPGA实现星载合成孔径雷达实时成像处理器中方位压缩处理的方法,完成了包括ISA接口、FFT运算、匹配滤波和复数取模在内的方位压缩处理器的设计。根据星上环境对器件的特殊要求,选用Xilinx的VirtexII系列FPGA进行硬件实现。对点目标仿真数据和实际数据的测试表明,该方法完全满足星上实时处理需求。     

税源集中度的分析方法

本文阐述了税源绝对集中度与相对集中度方法的内在联系,分析了各自的优缺点及对税收工作的影响。提出了赫佛因德指标分析法。     

煤矿数据集成技术研究与应用

本文分析了当前煤炭企业信息化水平低,信息孤岛现象严重,应用系统间相互隔离无法协同工作以及更上层次的集成应用更加困难的问题,提出了数据集成的目标,设计了该系统的体系结构,从而解决了不同平台间异构系统互操作以及数据多级综合利用的问题。并结合本系统的体系结构,详述了系统设计流程、实现过程和模式集成示例。     

Using a Heuristic-Systematic Model to assess the Twitter user profile’s impact on disaster tweet credibility

Journalists, emergency responders, and the general public use Twitter during disasters as an effective means to disseminate emergency information. However, there is a growing concern about the credibility of disaster tweets. This concern negatively influences Twitter users’ decisions about whether to retweet information, which can delay the dissemination of accurate—and sometimes essential—communications during a crisis. Although verifying information credibility is often a time-consuming task requiring considerable cognitive effort, researchers have yet to explore how people manage this task while using Twitter during disaster situations.To address this, we adopt the Heuristic-Systematic Model of information processing to understand how Twitter users make retweet decisions by categorizing tweet content as systematically processed information and a Twitter user’s profile as heuristically processed information. We then empirically examine tweet content and Twitter user profiles, as well as how they interact to verify the credibility of tweets collected during two disaster events: the 2011 Queensland floods, and the 2013 Colorado floods. Our empirical results suggest that using a Twitter profile as source-credibility information makes it easier for Twitter users to assess the credibility of disaster tweets. Our study also reveals that the Twitter user profile is a reliable source of credibility information and enhances our understanding of timely communication on Twitter during disasters.     

Identity on Social Networks as a Cue: Identity,Retweets, and Credibility

The current study investigates how social media affordances influence individuals’ source credibility perceptions in the presence of risk information, specifically examining how bandwagon heuristics interact with different identity heuristics at the individual level. The MAIN model and warranting theory serve as the theoretical framework to examine the effects of bandwagon cues and identity cues embedded in retweets and users’ profile pages for health and risk online information processing. A posttest-only experiment with a self-report questionnaire was administered to participants. Results indicate that different online heuristic cues impact the judgments of competence, goodwill, and trustworthiness. Authority cues strongly influenced source credibility perceptions. A reverse-bandwagon effect was observed in influencing source credibility judgments.