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31.
Xiaoming Zhou Martin Jacobsson Henk Uijterwaal Piet Van Mieghem 《International Journal of Communication Systems》2008,21(6):643-663
Although packet delay and loss are two important parameters of the Internet performance, to the best of our knowledge, the evolution of large‐scale IPv6 delay and loss performance has previously not been studied. In this paper, we analyze more than 600 end‐to‐end IPv6 paths between about 26 testboxes of RIPE Network Coordination Centre over two years, and compare the delay and loss performance over time with their IPv4 counterparts. We present and discuss the measurement methodologies and show that IPv6 paths have a higher delay and loss than their IPv4 counterparts. The main reason for the worse performance stems from IPv6‐in‐IPv4 tunnels rather than from native IPv6 paths and such tunnels are still widely used today. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
32.
It has been reported that it is harder to switch to a strong, well-practiced task from a weaker, less-practiced task than vice versa. Three experiments replicated this surprising asymmetry and investigated how it is affected by a reduction in interference between tasks. Experiment 1 progressively delayed the onset of the stimulus attribute associated with the stronger task. Experiments 2 and 3 separated the response sets of the tasks. Both manipulations reduced, without eliminating, interference of the stronger with the weaker task but reversed the asymmetry of switch costs, resulting in a larger cost of switching to the weaker task. The results are interpreted in terms of a model of the interactions between control input, task strength, and task priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
Madden Gregory J.; Begotka Andrea M.; Raiff Bethany R.; Kastern Lana L. 《Canadian Metallurgical Quarterly》2003,11(2):139
The degree to which real and hypothetical rewards were discounted across delays ranging from 6 hr to 1 year was explored in a within-subjects design. An adjusting-amounts procedure was used to estimate the subjective value of real and hypothetical rewards at each delay. A hyperbolic discounting function provided a significantly better fit to individual participants' preferences than did an exponential function. No significant effect of reward type on degree of hyperbolic discounting or area under the discounting curves was detected. These findings offer some support for the validity of using hypothetical rewards to estimate discounting rates in substance-abusing and other populations, but caution is suggested because this support is gleaned from a failure to detect an effect of reward type. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
35.
在传统的信号配时中,都是以减少车辆的总延误为目标,这样并不能很好地体现出整个社会中人的时间价值。现以减少所有通过交叉口的出行者的总延误为目标,在传统的信号配时方案的基础上,提出了一套新的配时方案,同时以减少全部出行者的总延误时间为目标给出了相应的延误评价公式,最后以杭州市文一路-古翠路口的实测交通数据进行分析,论证了本配时方案的有效性。 相似文献
36.
In many automatic face recognition systems,posture constraining is a key factor preventing them from application.In this paper a series of strategies will be described to achieve a system which enables face recognition under varying pose.These approaches include the multi-view face modeling,the threschold image based face feature detection,the affine transformation based face posture normalization and the template matching based face identification.Combining all of these strategies,a face recognition system with the pose invariance is designed successfully,Using a 75MHZ Pentium PC and with a database of 75 individuals,15 images for each person,and 225 test images with various postures,a very good recognition rate of 96.89% is obtained. 相似文献
37.
钨系延期药预点火反应机理研究 总被引:7,自引:3,他引:4
通过程控升温模拟点火条件,根据DSC图谱分析,找出主要反应区的温度范围。研究结果表明,钨系延期药预点火反应是一个真正的固-固反应。 相似文献
38.
介绍了扩频通信有效的MSK信号特点及声表面波MSK抽头延迟线构成方式,给出了声表面波32位MSK抽头延迟线的实验结果。 相似文献
39.
本文在Knockout交换结构的基础上,探讨一种新的ATM交换结构,使其本身带有优先权控制功能,以适应不同业务对信元丢失率及时延的不同要求。这种结构既能最大限度地有效利用系统资源,又能满足不同用户对业务质量的不同要求,并能降低交换结构复杂度。 相似文献
40.