分析和比较开放和封闭的移动平台外文翻译毕业论文精品_毕业论文

1、河南科技学院2015届本科毕业设计外文资料及翻译An Analysisand Comparison of Open and Closed Mobile1. In troduct ionInrecent years, the popularity of smart phone kept going up.More and more smart phones are sold anda lot of peopleareembraci ngthem. Smartphonesbroughtgreatconvenienceto users, as well created opport un ities

2、 for smart pho ne rese archers. That?s to say, the wide spread of smart pho nes ben efitedbothsides. At thesame time, developingofsmart phone OS becomes one of the smartest industry. To be a smart phoneOS,thesystem should: 1.Provideserviceslike a PC. 2.Workwitha GPU forbettervisualeffects.3. Allowth

3、e user to surf on Internet freely. And apparently, there ?re also some weaknesses:1.Limitedbattery. 2. Poor CPU performance against PC CPU. 3. Small storage. 4. The use of RAM may leads to loss of data when the phone runs out of batteryNow the 2 gia nts of smart phone OS are An droid and iPh one OS.

4、 On one side, An droid is based on Linuxkernel and Dalvik virtual machine,and it is open sourced. The upper layer of An droidis Java based,allow ingdevelopersto develop Androidapplications with Google SDK and sell their softwarein An droid Market. On theother side, iPho ne OS, which bases on Unix ke

5、rnel and Darwin model but is closed sourced,evol ves from Mac OS X and is the default OS ofiPhone,iPodTouch and iPad.Objective C based software can run in iPhone OS, and justlike An droid, you can develop your own iPhone applicationsandupload them onto Apple?s,AppStore ?forsale 1234.By compari ng th

6、e latest An droid and iPh one OS, An droid 2.2 Froyo and iOS 4, we can take a glimpse at the main featur e of openandclosed smartphone OSs.While the2 OSsaredesig nedinratherdiffere ntmen talityand fun cti on ality,it?s a little early to tell which one is better.2. Smart Phone OS2.1. An droidThe syst

7、em architecture of An droidcon sistsof 5 layers, which are LinuxKern el,An droidRun time,Libraries, Applicati onFramework and Applications,from bottom to top.An droidprovidescoreserviceslikesecurity,memory management, processmanagement, networkstackand drivers,bas ingonLinux2.6.Bei ngtheabstractlaye

8、rbetwee nsoftware and hardware,thelayerofLi nuxKernel hides theimpleme nti ngdetails ofhardwareandprovidesin tegratedservices for upper layer.Dalvik virtualmachi ne and Java core libraries are in eludedin the layer of An droidRun time,provid ing most fun cti ons inJava core libraries.The layer of Li

9、braries containsa class of C/C+ librariesforAn droidcomp onen ts. Those libraries are in tegratedby thelayer of ApplicationFramework and then provided to developers.The layer of Application Framework provides all kinds of mod ules for program in itializatio nto simplify the use of componen ts,allow

10、ingdevelopers do whatever they want and provideservices for other softwares, un der thelimitati onof security, of course.Mai nstream applicati ons are locatedin the layerof Application, including e-mail,SMS, calendar, Google map, Web browserand con tacts.Users in teractdirectly with this layer 1 2.T

11、he latest versi onof An droid,An droid2.2 Froyo, puts on some new features.They are: 1. SupportFlash 10.1, enablesuser to watch flash on the phone. 2. V8 JavaScript engine in web browser leads to faster In ternet data tran sportati on.3. Big advanee innetwork sharing.You can use the phoneas a 3G NIC

12、,orcon vert 3G sig nalto Wi-Fi.4. Automaticallysoftware update.5. Softwares can be setup inSD card toexte nd file storages.2.2. iPhoneiPhone OS isconsistof 4 abstractlayers:Core OS, Core Service, Media and Cocoa Touch respectively.langu to CFNis uLayers of Core OS and Core Service are designed in C

13、age to han dle core system services,en abli ng developersperform fileaccess, sockets calli ngand data han dli ng.etwork and SQLite are also parts of these 2 layers.The layer of Media, accordi ngto itsn ame, this layersed to controlvideo and audio, as well handle 2D and 3D images. The Open GL-ES Qura

14、tz part of the layer is coded w ith C Ianguage, while the part of Core-Audio and Core-Animat ion is Objective C based.The layer of Cocoa Touch builds a basic framework for all kinds ofprogramsiniPhone.Mostprograms run in CocoaTouch layer, and it ?s surely Objective C based 34.The latestiPhoneOSis iO

15、S4. It includes the following new features:1.Software classification. Thisfeature en ables user to placesorted softwares into differe ntdocume nts, making it clearerto man age. 2. Email in tegration. One accountis for all e-mails fromdifferentproviders.3. iBook, originally from iPad, is built in iOS

16、. 4. A br and new Apple Game Centermakes iPhone a tremendous entertainment platform.2.3. An droid vs.iPho neBeing the top 2 smart phone OSs, we?re sure that both Andrand disadva ntages. and see what uniquwhich means you c And iOS 4, officia fact a play of coauthorized by Apploid and iPhone have thei

17、r own advantages Now let ?s take a look at each of them, e feature they have.An droid 2.2 Froyo fullysupportmultitask,an liste nto music while writi ng blog.lly announced to be ,multitasked ? is in ncept. Only a few of softwares which aree can run,simultaneously ? whose principle is much easier that

18、 multitask:whe nan applicati onis switched out, itscurre nt state is saved and the n the system just closes it. And when it ?s switched in, we?re back to the previous snapshot67.During the publicati on of An droid 2.2 Froyo, Google announ ced it has ,the most flue ntweb browser ?,because the use of

19、V8 JavaScript engine. V8 is a brand new engine,designedforrunning big size JavaScript application. In some kind of t ests, V8 is much fastertha n JScript fromIn ternetExplorer,SpiderM on key from Firefoxand JavaScriptCore from Safari. Itall owe to3 key partsof V8, they ?re fast attributeaccess,dyn a

20、mic code gen erati on,effective trash clea ning.2.3.1. Fast Attribute AccessJavaScriptisa kind of dynamic Ianguage,whichmeans attributes can be added or deleted at run time, and they ?re freq uen tly cha nged. Most JavaScript engines use a dict ionary styl e structure to store the attributes of an o

21、bject, so it re quires a whole dicti onary search to find the positi on of at tributes in memory.lt ?s quiteinefficientand it ?s slower than Java and Smalltalk.To solvethis problem,V8 discardeddynamic search and realized itin a differe ntway: Create hidde n classes for objects dynamically.In JavaScr

22、ipt, every time when we?re addinganew attribute to an object,we create a subclass withthenew attributefrom a hidden class as the super class.It ?sa recursive course and the above performa neehappe ns onlyonce when we first do this. Later we just use the previous hidden subclass when we?re in the sam

23、e situation. So there?s no n eedto repeatoperatio n and createadict ion ary.This leads tothe saveof timeand energy,aswell makeiteasier for theimpleme ntati onof classoptimizati onand innercache 4.232.Dynamic Code GenerationWhen JavaScript is running for the very first time, V8 tran slate it directly

24、 into localmach ine code, rathertha nexplain it to bytecode. Attribute access is done by inner cache, which isoftentranslated intoinstructionsby V8 at runtime.When it comes to the code where certainobject is accessed,V8 tries to find the curre nthidde n class.Mean while,V8assumes that allobjects in

25、the snippet are describedbythe same hiddenclass, so V8 willmodifycorrespondinginnercache to make the directuse of the hidden class more convenient. If thisassumptio n is correct, the access of attribute s can be all done in only 1 in structi on.Eve n if the predictio nfails,inner cache is modified a

26、ga in by V8, which wor?t take too much time and resource. When one hidden class is shared by a lot ofobjects,the access speed can beclose to most dynamic Ianguageaccess speed. Inner cache andhidde n class,mixed with dyn amic code and class optimization, improve theefficie ncyof JavaScript at a large

27、 scale. Effective Trash Clea ningV8 does memory recycles automatically. To guaranteethe speedof object distributi on,aswell cutthe timeof trash cleaning and clear fragmentup,V8 willinterruptthe runningapplicationwhen performing trash cleaning. Mostly, only a small part of object stackisinvo I

28、vedin trashclea ning cycle, so thein terrupti oncaused little. Alllocati onof objects and poi ntersare logged by V8, so the system wor?t takeobjectforpointer andmemory overflow is avoided 4.Besides,themost flue ntweb browser?,Google collaboratedwith Adobe and An droid2.2 Froyo fully supports Flash.

29、That ?sto say, not only flash media,but allflash web pages can display perfectly on An droid.To the con trary, Apple turned down Adobe and take HTML5 as iPhone?s web protocol, makin g itunableto show some flash based animation.An droid2.2 Froyo also leads the way inn etwork shari ng.Smart phone with

30、Froyocan be conn ectedtoaPC as a 3GNIC,and can alsoconvenien tlycon vert3Gsig nalto Wi-Fi.iOS4 can do thefirsttoo, butfailedto convert 3G toWi-FiVideo conferenceisboth supportedbyFroyoand iOS 4,butthe con diti onsarediffere nt.YoucanseeaFroyo userviacamera as longasyou get a cameraalso.However, iOS

31、4user can onlydo video talktoanotheriOS 4 user, whichis a big limitatio n.While An droid is asce ndant in n etwork in teracti on,Apple isunique in itsfrie ndshipand en terta inmen t.Theadded featureof ,softw are classification ? enablesuser to place sorted softwaresin todiffere ntdocume nts,maki ng

32、it clearer to man age.What?s more, there ?re hundreds ofthousands applications inAppStore, meaning thatiPho ne can have up to hun dreds of thousa nds fun cti ons.This is a ratherremarkable feature that Apple publicizes.And the most convincing pointgivenby Apple, is that ,Android looks exactly famili

33、ar withiPhone. ? Although it ? justa subjective sen se, the born of iPh one really brought big revolution to the phone industry,and thename ,Apple ? itself is a world famous brand 78.3. Open and Closed platforms3.1. SDKThe most importa ntpart of every develop ing platform is SDK,enable 3rd party dev

34、elopers to make software for the platf orm. Usually, libraries, debug tools and emulators are includ ed in SDK. Differentplatforms distribute their SDKs differently. Some SDK is complete free and open, while others are strictly limited.Developers of ope n platforms can get and modify part or all of

35、the source code. Google and Linux are leaders of ope n platforms;theypublicizedthewholesource codeofAn droidandLinux. Thegoodpointisthat,platform ownerscan save agreatamount oftimeanden ergy develop ingandmain taining the platform,because 3rd party developers will do thisforthem.Withlessmoney spent

36、ondevelopmentandmaintenance, a relativelylow price can attract more and more phone users.Con trarily, closed platforms lock their source code in the s afety and forbid 3rd party accesses. Apple and Microsoft are the represe ntatives of them, they arebothclosed sourced,butsome differences do exists.

37、3rdparty iPhoneapplications are restrictedwithin n arrow limits,forthat Apple willlookthrough everyapplicati onwhichis uploadedon to ,AppStore ? and a lot of applicationsare turned down.Microsoftdon?t check Windows applicationsat all, it all depends onthe users themselves. You in stalledthe mareware

38、, you suffer the loss.3.2. Applicati on MarketMarket is the medium between developers and users, hence it ?s very importa nt. d more application rrent for iousSoftwaresevery ir own compete rs. ess istmarkets, both their products, markets.from Nokia, market. applicatio n with eachHowever, the and cha

39、os, indiffere ntCorresp ondin gly, uld be sold no competitor. f sole und ininSome predictedthattheremarkets whilesomedon?tdo exist. Some specify while othersselltheirwill thi nkonly onesoftwaresbeso.more an In cu market invarby itself. ore ? is ot of prettyAnd a big is ,jailbreak ,Jailbreak ? isMicr

40、osoft and Linux Mobile are can release markets have is good forDevelopers of these platformssoThisin other lack of softwares markets,whatever markets, for a livi ng. uni versal thatsoldmanagement may lead have the same functionality users a lot.most applicatio ns leadswhichcon fusesthatinthetouseto

41、mexshotosole markets claim them. This kind ofmono polizati on,App Store ? and ?AndroidMarket? are deputy oNormally,iPhone applications can only be foand Apple will check every one of them in ,App St news is that a l for various by hackers,markets.,App Store ?,Good news isofficially tested, good soft

42、wares uno fficial ? and ,SIM a process rootcheck every every applicati on Badthatit ?s safe;are rejected builtmechanism is uniock ?.thatreas onsthatTouch users to gain stem thus removing e. Once jailbroken, exte nsionsand themesaccessiPad, uni ockiPhone and the operat ingiPodsyany limitati ons iPh o

43、ne users previouslyallowsandimposed upon them by Appl are ableun availableto dow ni oad through themanyAppStoreviain stallerssuch as Cydia.Ajailbroke niPad,iPhone oriPodTouch isstillable tousethe AppStoreand iTunes9.,SIM lock ? isbuiltinto GSM pho nes byAnd amobile phone manufacturers. providers use

44、 this phones to specifica capability Network to andphones can be lockedIntern ati onalit possible toiescapability coun tries to accept Subscriberrestrict n etwork only SIM Ide ntity.the use of these providers.Ge nerally, cards,SIM unlock ?based on the make countrMobileuse a mobile phone withoutconsi

45、deringby mobilephone manufacturers.does n?ttestan officialrelease problems,and n etworks specifiedGoogle there ?sAn droid, although you can still want.Con sideri ngsecurityHowever inall, so plicatio ns,every applicati on marketsome components. Like ,jailbreake, ,root ? in An droid gives usersat for

46、An droid ap your productany where youGoogle banned the use of iPho n devi? and ,SIM unlock ? in 100% control of theirces, along with some security risks. ,Root? is a process th at allows users of cellph onesrunning the An droidoperat ingsystem to atta in privilegedcon trol(known as root access)withi

47、n An droids Linux subsystem, similar tojailbreaki ngonApple devices running the iOS operati ng system,overco minglimitati onsthat the carriers and manu facturers put on suchphones. Rootingmakesit possible touse customversions ofthe An droidsystem such as CyanogenM od, support ing featuresunavailable

48、 instock ROMs. Italsoallows fornewer versions of An droidnot supplied by the orig inal device manu facturer. In con trastto iOS jailbreak ing, rooti ng is notn eededto run applicatio nsnot distributed by the official An droidMarket. It isneeded however, when trying to access paid Androidapplicati on

49、sfrom coun tries which are not part of thepaid applicati ons market.33In tegrati onSome companies focus only on their core industry, i.e. devel op an operati ng system and provide an en vir onmentfor 3rd party developme nt. Others not only do these, but man age the process ofdevelop inga software to

50、 publiciz ing it.Depe ndingon thein tegrati onof platforms, we sort them to 4 kin ds:fullin tegrati onplatform, market in tegrati onplatform, device in tegrati onplatform and noin tegrati onplatform.The publiciz ing modelof fullin tegrati onplatformis very strict. Its management ranges from device m

51、anufacturing to app licationrelease, whose representative is Apple. Apple ?s factory produces iPhone, Apple ?s,App Store ? sellsapplication,Apple ?s ,iTunes ? is the channel of Apple?s resources. The whol e process is un der Apple ?scon trol.Market in tegratio n platformscommit themselvesto develop

52、ingand selli ng softwares. Google is one of them.Un likeapple,Google don?t have a factoryto manufacture itsown handsets,but only developed An droidand set up ,An droid Market? forAn droidapplicati ons. However, compa nies like Google defi nitelyhave the capabilityto produce itsown devices. Google is

53、 in good relationshipwith HTC, who is the OEM of T-Mobile, 02 and Orange, etc.Device integrationplatforms produce their own handsets, butdon?t set up applicationmarkets. Forexample, RIM makes Blackberry, but there ? no officialapplicationmarket for Blackberry. No integration platforms do few things.

54、Microsoft neither makes mobile phones, nor sets up a market.What they do i s only developing the operatingsystem: Windows Phone 7.分析和比较开放和圭寸闭的移动平台1 介绍近年来，智能手机的普及率不断攀升。越来越多的智能手机被卖出和很多人都更 加青睐于它们。智能手机给用户带来了极大方便，并为智能手机研究者创建了机 会。这就是说，智能手机的广泛普及，对双方都有利双方。同时，智能手机操作 系统发展成为最智能的行业之一。要成为一个智能手机操作系统，该系统应：1. 提供服务P

55、C式的服务。2.使用GPU#到更绚丽的视觉效果。3.允许用户在互联网上自由地冲浪。显然，它们也有一些弱点：1,电池的限制。2。较电脑CPU来说，手机CPU性能差。3.存储空间小。4.在手机电池耗尽时，RAM的使用可能会导致数据丢失。现在智能手机操作系统的两巨头是An droid和iPho ne OS 一方面，An droid是基于Linux内核，Dalvik虚拟机，它是开源的。上层的 An droid是基于Java 的，允许开发者使用谷歌SDK开发An droid应用程序和在An droid 市场销售他 们的软件。另一方面，iPhone操作系统基于Unix内核和达尔文模型，但它是封 源的，是从Mac OS X继承而来，是iPhone，iPod Touch和iPad默认的操作 系统。基于C语言的软件可以在iPho ne OS上运行，就像An droid，你可以开 发自己的iPhone应用程序，并上传到苹果的 App Store进行销售。通过比较 An droid 和 iPh one OS 的最新系统：An droid 2.2 Fro