流媒体代理缓存算法研究

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1、华中科技大学博士学位论文流媒体代理缓存算法研究姓名：余江申请学位级别：博士专业：通信与信息系统指导教师：杨宗凯20060401本文利用K变化下的Zipf-like模型，提出了一个基于参数模型的流媒体分段缓存算法。通过对模型关键参数的获取及更新方式进行有效设计，使得该算法可以使用较少的额外缓存空间代价，获取较为精确的流媒体内容流行度分布情况，从而获得较好的缓存性能表现。3）针对异构用户环境中，在一定缓存空间的限制下，提高满足用户观看质量的程度与降低骨干网带宽消耗是一对矛盾指标的问题，结合精细粒度可扩展编码方式，本文提出了一种缓存方案和发送方案自适应的流媒体缓存算法。仿真结果证明，该算法

2、可以在满足一定骨干网带宽消耗的前提下，使得整体用户观看流媒体的质量满足程度达到最高。关键词：流媒体，代理缓存，内容流行度，分段缓存，可扩展编码IIAbstractWithmoreandmoremultimediaapplicantion,manyresearcheshaveattachedimportancetothestreammediathatcanprovidethecapacityof“DownloadingandPlaying”andallowspeopletoenjoythecontinuousmediaonline.Withpopularizingthetypicals

3、treamsystem,suchasVideo-on-Demand,VideoConferenceandE-Learningetc,themultimediatraffictakesthelargestportioninthecurrentInternettraffic.However,thereissomeobviousdifferencebetweenstreammediaandnon-streammedia.a)Streammediawillconsumemorebandwidththannon-streammedia;b)Clientswillbemoresensitiveo

4、nstartupdelaywhentheyusestreammedia;c)Heterogeneousclientswillaskdifferentqualityrequirementforreceivedmediaaccordingtotheirownenvironment.Thisbringsnewchallengesandpressurestonetworksandstreammediatechnologyinthefollowingfields,includingtheassuranceofqualityofserviceforstreammedia,theassurance

5、ofstreammediasystemperformanceandtheinfluenceofheterogeneousclientbehaviorandnetworkenvironmentonstreammediatransmission.Tosolvetheaboveproblemsthroughprovidingnetworkedgeservicecapacity,thisthesisaddressesontheproxycacheofstreammedia.Thecontentofthisthesisincludesfourissues:(1)modelingandanaly

6、sisofstreammediainternalpopularitydistribution;(2)prefixstreammediacachingalgorithmbasedoninternalpopularitydistributionmodel;(3)prefixlengthandqualitytwo-dimensionadaptivestreammediacachingalgorithm.TheworksinthisthesishasbeensupportedbytheNaturalScienceFoundationofChina“InvestigationofWireles

7、sMultimediaTechniquesbasedonMultimediaTransmissionProperty”(No.60202005)and“Internet-basedinteractivestreamingdeliverytechnique”(No.60302004)respectively,andalsosupportedbytheAustralianResearchCouncilFoundation“Interactivevideo-on