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191.
Epidemic路由算法是一种多副本路由算法,在资源受限的情况下,会由于无限制的洪泛使得网络中存有大量的消息副本,消耗大量网络资源,导致网络性能下降。针对Epidemic路由算法中存在的问题,提出一种基于节点协作的Epidemic路由算法,该算法通过节点间相互的协作和一定策略抑制网络中副本数多的消息的转发机会,提高副本数少的消息的转发机会,进而控制网络中总的消息副本的增长,以此保证消息转发公平性和较好的网络性能。仿真结果表明,与传统的Epidemic路由算法和Prophet路由算法相比,该路由算法能显著提高消息的交付率,减少消息传输延迟和路由开销,有效提高了网络总体性能。  相似文献   
192.
Online courses play an increasing role in professional development of environmental educators, yet little information is available on the interactive processes involved in online learning. We examined the relationship of three types of interactions in an urban environmental education online course – participant–participant, participant–instructor, and participant–content – to four course outcomes: participants’ motivation to learn, intent to adapt ideas and information learned through the course in their practice, actual adaptation of ideas in their practice, and development of professional networks. Content analysis was used to characterize participants’ and instructors’ weekly online posts and comments, and generalized estimation equation modeling was used to explore the relationships between interactions and outcomes. The results showed that participant–content interaction had significant positive relationships with participants’ motivation to learn, intent to adapt ideas, and adaptation of ideas. Participant–participant interaction had significant positive relationships with participants’ motivation to learn, and development of professional networks with each other. Finally, participant–instructor interaction had a significant positive relationship with participants’ development of professional networks. The results of this study can be used to improve professional development online courses for environmental educators.  相似文献   
193.
从知识管理角度对CoPS进行了研究,提出了CoPS环境下KM影响因素、KM活动、研发绩效的关系模型。通过问卷调查,本研究收集了217个有效的样本数据,经过分析,得出以下主要研究结果:(1)复杂的知识特性是CoPS复杂性的根本;(2)CoPS环境下关键KM活动是知识创造和知识整合;(3)CoPS环境下KM活动对"KM影响因素-研发绩效"有着中介作用;(4)验证了CoPS环境下KM影响因素、KM活动、研发绩效的关系模型。  相似文献   
194.
本文归纳和比较了在配电网中理论线损计算的两类常规方法:基于均方根电流原理的近似计算和潮流计算,概括地阐述了几种常见方法的基本原理和优缺点,并在此基础上提出了一种优化算法的思想.  相似文献   
195.
Political polarization remains perhaps the “greatest barrier” to effective COVID-19 pandemic mitigation measures in the United States. Social media has been implicated in fueling this polarization. In this paper, we uncover the network of COVID-19 related news sources shared to 30 politically biased and 2 neutral subcommunities on Reddit. We find, using exponential random graph modeling, that news sources associated with highly toxic – “rude, disrespectful” – content are more likely to be shared across political subreddits. We also find homophily according to toxicity levels in the network of online news sources. Our findings suggest that news sources associated with high toxicity are rewarded with prominent positions in the resultant network. The toxicity in COVID-19 discussions may fuel political polarization by denigrating ideological opponents and politicizing responses to the COVID-19 pandemic, all to the detriment of mitigation measures. Public health practitioners should monitor toxicity in public online discussions to familiarize themselves with emerging political arguments that threaten adherence to public health crises management. We also recommend, based on our findings, that social media platforms algorithmically promote neutral and scientific news sources to reduce toxic discussion in subcommunities and encourage compliance with public health recommendations in the fight against COVID-19.  相似文献   
196.
设计了一种基于无线传感网络的机器人竞赛裁判系统.开发了机器人击打感应道具、全场定位系统、WiFi无线数传网络.实现了比赛中各机器人和比赛道具状态通过无线方式与裁判系统实时通信,显示比分和自动判罚的功能.能够实时感知场上所有机器人的状态、位置信息,并记录、统计、显示双方机器人的得分情况,减少人工裁判的误判、漏判现象,有效...  相似文献   
197.
Early research on the social implications of e-mail has promoted the role of electronic communication channels in fostering social equality and reducing gaps between the social classes. Follow-up studies, however, suggest that people continue to rely on social cues in electronic communication as a way of dealing with uncertainties and reducing feelings of discomfort associated with unfamiliar contexts. Based on a review of the Social Cognitive Theory, social status and electronic communication literatures, along with the results of a previous qualitative study, we propose a formal model that indicates how self-perceptions of social status are related to the use of e-mail and the acquisition of social resources over electronic channels. The model is tested using data collected from 206 faculty members in a major U.S. university. The empirical results support the proposed model implying that self-perceptions of social status influence social assertiveness, which in turn reinforces the use of e-mail to seek help and acquire social resources from others. The use of e-mail for the acquisition of social resources is associated with a socially diverse network whose contacts are perceived to acquire valuable information and to extend instrumental support for career development. Implications are drawn for both theory and practice.  相似文献   
198.
利用多人博弈的思想对簇内节点间协作和竞争的关系进行分析,提出一种簇内信息融合算法。通过仿真实验对节点能量消耗的均衡性、网络生存周期及信息融合精度等方面进行性能评估验证该算法的有效性。  相似文献   
199.
建立并评价了一种简单灵敏的方法测定狗血浆中PZS的含量.该方法利用HPLC-FLD结合乙醚萃取的前处理方法,采用C18色谱柱(150 mm×4.6 mm,5 μm),流动相为30%乙腈和70%乙酸-乙酸钠缓冲液(pH=3.6),荧光检测器的激发波长为258 nm,发射波长为387 nm,在流动相流速为1.0 mL/mi...  相似文献   
200.
遗传算法是一种较新的工程优化算法,将其引入给水管网优化设计,增强了管网设计方案的经济合理性。对给水管网优化设计的数学模型建立,遗传算法的基本原理、实数编码技术、评价函数的建立进行了分析,并用实例验证了其有效性。  相似文献   
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