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TheimpactofAjaxonnetworkperformanceWeb2.0hasbeenbecomingthenewtendencyoftheInternetdevelopment.Inordertogetbettermanagementofweb2.0networkresourceandguaranteeofservicequality,thearchitectureandtheadvantagesofweb2.0overAjaxtechnologyisanalyzed,andtheimpactofAjaxonbandwidthperformanceofwebapplicationisdiscussed.AJAX技术对网络世界的影响与作用Acomponent-andpush-basedarchitecturalstyleforAJAXapplicationsAnewbreedofwebapplication,dubbedAJAX,isemerginginresponsetoalimiteddegreeofinteractivityinlarge-grainstatelessWebinteractions.Attheheartofthisnewapproachliesasinglepageinteractionmodelthatfacilitatesrichinteractivity.Alsopush-basedsolutionsfromthedistributedsystemsarebeingadoptedonthewebforAJAXapplications.Thefieldis,however,characterizedbythelackofacoherentandpreciselydescribedsetofarchitecturalconcepts.Asaconsequence,itisratherdifficulttounderstand,assess,andcomparetheexistingapproaches.WehavestudiedandexperimentedwithseveralAJAXframeworkstryingtounderstandtheirarchitecturalproperties.Inthispaper,wesummarizefouroftheseframeworksandexaminetheirpropertiesandintroducetheSPIARarchitecturalstylewhichcapturestheessenceofAJAXapplications.Wedescribetheguidingsoftwareengineeringprinciplesandtheconstraintschosentoinducethedesiredproperties.Thestyleemphasizesuserinterfacecomponentdevelopment,intermediarydelta-communicationbetweenclient/servercomponents,andpush-basedeventnotificationofstatechangesthroughthecomponents,toimproveanumberofpropertiessuchasuserinteractivity,user-perceivedlatency,datacoherence,andeaseofdevelopment.Inaddition,weusetheconceptsandprinciplestodiscussvariousopenissuesinAJAXframeworksandapplicationdevelopment.组建于工作流程结构方案特色的AJAX程序系统应用开发J2EEsupportforwirelessservicesJ2EE开发无线服务支持系统WeexplorebydesignandimplementationtheapplicabilityofJ2EE(Java2Platform,EnterpriseEdition)architectureinsupportingwirelessservicesaswellasweb-basedservices.Thishasbeendemonstratedbyimplementingawirelessprescriptionsystem,whichprovideswirelessservicestophysicians,andweb-basedservicestopharmaciesandadministrators.Thegoalofthewirelessprescriptionsystemistoimprovetheefficiencyofthehealthcaresystembyreducingtheoveralltimeandcostusedtocreatedocumentsandretrieveinformation.Wealsopresentaperformanceevaluationoftheimplementedwirelessprescriptionsystemusinglatencyastheperformancemetric.Inparticular,weinvestigatedtheoverheadsassociatedwithdifferentcomponentsoftheunderlyingJ2EEarchitecture,whichincludestheSessionBean,EntityBean,andthedatabase.Wefoundthatthelatencyoverheadsintroducedbythesecomponentsaccountfor3.8–4.3%,3.9–4.4%,and91.8%ofthetotaldelayexperiencedinsidetheJ2EEarchitecturerespectively.AschedulingframeworkforenterpriseservicesApplication-levelschedulingisacommonprocessintheenterprisedomain,butinordertobeproductiveitshouldbetime-effective,interoperableandreliable.Inthispaperwepresentthedesignandimplementationaspectsofamodularschedulingsolution,whichaimstofulfilltheabove-mentionedrequirements.Theproposedsolutionconstitutesanintegralpartofanexistingserviceprovisioningplatformtargetedtothelocationbasedservices(LBS)domain;howeverapplicationtootherservice-orientedarchitecturesisalsopossible.Acarefuldesignprocessisfollowedinordertoidentifythescheduler’sfunctionalsubsystemsandtherelationshipsbetweenthem.TheimplementationisbasedontheJ2EEframework,thusguaranteeingindependencefromunderlyingtechnologiesandapplicabilityinenterpriseenvironments.Thehighqualityandscalabilityoftheschedulerisalsovalidatedthroughanintensiveperformanceanalysis.J2EE开发企业服务平台框架ResearchanddesignofwapservicesystembasedonMISCplatformJ2EE开发wap无线通信服务平台系统设计方案Wirelessapplicationprotocol(WAP)havebecometheavailablemethodforsubscriberstoaccessmobileInternetthroughmobileterminal,regardlessofthelocationandtime.Inthisarticle,alogicalarchitectureofWAPservicesystembasedonmobileinformationservicecentre(MISC)[1,2]platformisdiscussed.ThewholesystemisdesignedanddevelopedonJava2enterpriseedition[3](J2EE)architectureanddeployedonBEAWebLogicServer[3,4].Furthermore,aseriesofvariousWAPservicesbasedonthissystemhavebeenimplemented,whichvalidatesthepracticevalueofthissystem.Thisoptimalschemepresentedinthisarticlewillreducethedevelopmentcomplexity,deploymentrisk,andsoon.VisualizingforestlandscapesusingpublicdatasourcesThree-dimensional(3-D)visualizationsofforestlandscapesarequantitativeecologicalinformation-basedtechniquesthatcanbeusedtovisualizeforeststructure,dynamics,landscapetransformationsandregionalplans.Visualizingforestsandlandscapeswithlimitedgroundobservationsareoftentheprimarychallengeforqualityanimations.Conductingstand-levelfieldsurveysoveralargeforestareaistimeconsuming,labor-intensiveandexpensive.Analternativeistouseexistingpublicdatasets.WeusedtheForestInventoryandAnalysis(FIA)databaseandotherexistingvegetationdata,classifiedLandsatTMimagery,measurementsoftreearchitectureandForestVegetationSimulator(FVS)tovisualizeaforestlandscapeintheWashburnDistrictoftheChequamegonNationalForest(CNF)innorthernWisconsintogenerateusefulinformationforresourcemanagementatmultiplescales.Realisticimagesfortreespeci