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51.
Scheduling algorithms are used in content delivery systems to control the resource allocation rate. They not only improve system efficiency, but also increase user satisfaction. Lower renege rate and less waiting time for users are the main goals for a scheduling algorithm. Among existing algorithms, On-Demand strategy does not perform well, while rate control channel allocation policies performs much better. Pure-Rate-Control (PRC) and Multiple-Service-Class (MSC) belong to the rate control algorithms. MSC performs well, but a drawback is that it uses the Hot Index, which is hard to decide and has significant effects on the performance. In order to solve this problem and to improve the overall system performance, two new algorithms, Modified MSC(MMSC) and Adaptive Algorithm (AA), are proposed in this paper. Both of them solved the problem of MSC very well and improved the overall performance. For example, the renege rate of AA is about 5.4% less than that of MMSC, and about 9.8% less than that of MSC.
Yun ZhangEmail:
  相似文献   
52.
Homogeneous and nano-sized BPNT [(Ba1-xPbx)Nd2Ti5O14] powders were prepared under various hydrothermal conditions. Crystallinity and homogeneity of the synthetic powders were investigated. The microwave dielectric properties of the filters prepared with hydrothermal powders were compared with those of the filters prepared with conventional powders. The microwave dielectric properties of the filter prepared with the hydrothermal powders were also better than those of the filter manufactured with the conventional powders. The dielectric constant, quality constant and temperature coefficient of resonance frequency of hydrothermally prepared filter under optimum condition and measured at 3.5 GHz around were about 93, 6067 and 0 ppm/°C, respectively.  相似文献   
53.
This paper describes a scheme for proactive human search for a designated person in an undiscovered indoor environment without human operation or intervention. In designing and developing human identification with prior information a new approach that is robust to illumination and distance variations in the indoor environment is proposed. In addition, a substantial exploration method with an octree structure, suitable for path planning in an office configuration, is employed. All these functionalities are integrated in a message- and component-based architecture for the efficient integration and control of the system. This approach is demonstrated by succeeding human search in the challenging robot mission of the 2009 Robot Grand Challenge Contest.  相似文献   
54.
55.
以实用英语教材中的课文为例,分析了语篇模式在高职英语教学中的应用.在此基础上阐释了语篇模式教学在高职英语教学中的优势,即有利于把握篇彰结构,理解篇章内容,认识词汇变化形态,进而有效提取关键信息,不断提高写作水平.  相似文献   
56.
玻璃网格板是一种相互垂直的纵、横刻线的二维线纹标准器,用来检测航测仪器、遥感仪器和各类二维坐标测量仪器的精度,因此,它的精度直接影响待检仪器的精度。结合计量圆光栅的制作工艺,详细介绍了基于光刻胶的玻璃网格板新型制作工艺,检验结果表明该种工艺制作的玻璃网格板线条均匀,280mm内刻线间距精度小于1μm。  相似文献   
57.
通过分析霍桑短篇小说《自我主义;或心底之蛇》中"蛇"的隐喻义,聚焦于作者的罪恶观,并阐释这种罪恶存在的根源、危害及其救赎良方。  相似文献   
58.
校园文化是思想政治教育重要的载体,具有育人导向、渗透和熏陶、约束、规范和传承、融合、创新文化等功能,本文依据时代的特征,从"两课"进网络文化、加强对校园文化活动的思想导向;结合本院社团文化活动的实际,阐述了对校园文化思想政治功能实现问题的看法。  相似文献   
59.
This paper deals with algorithms for text localization and character segmentation in images for process automation in the steel-making industry. Each character which comprises slab identification numbers may be corrupted severely before it is captured by network cameras. Therefore, proper processing is required to localize the target texts successfully. In this paper, we propose (1) a method to evaluate the closeness of an edge patch to the form of a closed contour, (2) an edge inspection method to determine character colors and estimate font thickness, and (3) three reasonable binarization methods to increase the performance of the algorithm for the detection of the left and right boundaries of the text rectangle. The experimental results show that the proposed algorithms are reliable.  相似文献   
60.
Dynamics of polymer electrolyte fuel cells undergoing load changes   总被引:1,自引:0,他引:1  
Yun Wang 《Electrochimica acta》2006,51(19):3924-3933
Numerical simulations are carried out for a single-channel polymer electrolyte fuel cell (PEFC) undergoing a step increase in current density. The objective is to elucidate profound interactions between the cell voltage response and water transport dynamics occurring in a low-humidity PEFC where the membrane hydration and hence resistance hinges upon the product water. Detailed results are presented to show that a step increase in the current density leads to anode dryout due to electroosmotic drag, while it takes several seconds for water back-diffusion and anode humidified gas to re-wet the anode side of the polymer membrane. The water redistribution process is controlled by water production, membrane hydration, electroosmotic drag, and water diffusion in the membrane. The anode dryout results in a substantial drop in cell voltage and hence temporary power loss. Under extreme situations such as dry anode feed, large step increase in the current density, and/or lower temperatures, the cell voltage may even reverse, resulting in not only power loss but also cell degradation. Finally, the dynamics of current distribution after a step change in gas humidification is numerically examined.  相似文献   
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