無線局域網-計算機畢業(yè)論文外文翻譯

1、<p>　　畢業(yè)設計(論文)外文資料翻譯</p><p>　　系： 信息工程學院 </p><p>　　專 業(yè)： 計算機科學與技術 </p><p>　　姓 名： </p>

2、<p>　　學 號： </p><p>　　外文出處：Chris Haseman. Android-essential</p><p>　　s[M].London:Spring--Verlag,2008</p><p>　　.8-13. </p&g

3、t;<p>　　附 件： 1.外文資料翻譯譯文；2.外文原文。 </p><p>　　注：請將該封面與附件裝訂成冊。</p><p>　　附件1：外文資料翻譯譯文</p><p><b>　　無線局域網</b></p><p>　　為何使用無線局域網絡</p><p>　　對于

4、局域網絡管理主要工作之一，對于鋪設電纜或是檢查電纜是否斷線這種耗時的工作，很容易令人煩躁，也不容易在短時間內找出斷線所在。再者，由于配合企業(yè)及應用環(huán)境不斷的更新與發(fā)展，原有的企業(yè)網絡必須配合重新布局，需要重新安裝網絡線路，雖然電纜本身并不貴，可是請技術人員來配線的成本很高，尤其是老舊的大樓，配線工程費用就更高了。因此，架設無線局域網絡就成為最佳解決方案。</p><p>　　什么情形需要無線局域網絡</p&

5、gt;<p>　　無線局域網絡絕不是用來替代有限局域網絡，而是用來彌補有線局域網絡之不足，以達到網絡延伸之目的，下列情形可能須要無線局域網絡。</p><p>　　無固定工作場所的使用者</p><p>　　有線局域網絡架設受環(huán)境限制</p><p>　　作為有線局域網絡的備用系統(tǒng)</p><p>　　無線局域網絡存取技術<

6、;/p><p>　　目前廠商在設計無線局域網絡產品時，有相當多種存取設計方式，大致可分為三大類：窄頻微波技術、展頻(Spread Spectrum)技術、及紅外線(Infrared)技術，每種技術皆有其優(yōu)缺點、限制及比較，接下來是這些技術方法的詳細探討。</p><p><b>　　技術要求</b></p><p>　　由于無線局域網需要支持高速、

7、突發(fā)的數(shù)據(jù)業(yè)務，在室內使用還需要解決多徑衰落以及各子網間串擾等問題。具體來說，無線局域網必須實現(xiàn)以下技術要求：</p><p>　　可靠性：無線局域網的系統(tǒng)分組丟失率應該低于10-5，誤碼率應該低于10-8。</p><p>　　兼容性：對于室內使用的無線局域網，應盡可能使其跟現(xiàn)有的有線局域網在網絡操作系統(tǒng)和網絡軟件上相互兼容。</p><p>　　數(shù)據(jù)速率：為了滿

8、足局域網業(yè)務量的需要，無線局域網的數(shù)據(jù)傳輸速率應該在1Mbps以上。</p><p>　　通信保密：由于數(shù)據(jù)通過無線介質在空中傳播，無線局域網必須在不同層次采取有效的措施以提高通信保密和數(shù)據(jù)安全性能。</p><p>　　移動性：支持全移動網絡或半移動網絡。</p><p>　　節(jié)能管理：當無數(shù)據(jù)收發(fā)時使站點機處于休眠狀態(tài)，當有數(shù)據(jù)收發(fā)時再激活，從而達到節(jié)省電力消耗

9、的目的。</p><p>　　小型化、低價格：這是無線局域網得以普及的關鍵。</p><p>　　電磁環(huán)境：無線局域網應考慮電磁對人體和周邊環(huán)境的影響問題。</p><p>　　Android是Google開發(fā)的基于Linux平臺的開源手機操作系統(tǒng)（在華注冊商標名為“安致”）。它包括操作系統(tǒng)、用戶界面和應用程序——移動電話工作所需的全部軟件，而且不存在任何以往阻礙移

10、動產業(yè)創(chuàng)新的專有權障礙，號稱是首個為移動終端打造的真正開放和完整的移動軟件。Google與開放手機聯(lián)盟合作開發(fā)了Android，這個聯(lián)盟由包括中國移動、摩托羅拉、高通和 T-Mobile在內的30多家技術和無線應用的領軍企業(yè)組成。Google通過與運營商、設備制造商、開發(fā)商和其他有關各方結成深層次的合作伙伴關系，希望借助建立標準化、開放式的移動電話軟件平臺，在移動產業(yè)內形成一個開放式的生態(tài)系統(tǒng)。</p><p>

11、　　它采用了軟件堆層(software stack，又名軟件疊層)的架構，主要分為三部分：底層以Linux核心為基礎，由c語言開發(fā)，只提供基本功能。中間層包括函數(shù)庫Library和虛擬機Virtual Machine，由c++語言開發(fā)。最上層是各種應用軟件，包括通話程序，短信程序等，應用軟件則由各公司自行開發(fā)，以Java編寫。</p><p>　　為了推廣此技術，Google和其它幾十個手機公司建立了開放手機聯(lián)盟

12、（Open Handset Alliance）。</p><p><b>　　特性</b></p><p>　　應用程序框架：支持組件的重用與替換 </p><p>　　Dalvik虛擬機：專門為移動設備做了優(yōu)化 </p><p>　　內部集成瀏覽器：該瀏覽器基于開源的WebKit引擎 </p><p

13、>　　優(yōu)化的圖形庫：包括2D和3D圖形庫，3D圖形庫基于OpenGL ES 1.0 （硬件加速可選） </p><p>　　#SQLite：用作結構化的數(shù)據(jù)存儲 </p><p>　　多媒體支持：包括常見的音頻、視頻和靜態(tài)印象文件格式（如MPEG4， H.264，MP3，AAC，AMR，JPG，PNG，GIF） </p><p>　　GSM電話（依賴于硬件）

14、</p><p>　　藍牙Bluetooth，EDGE，3G和WiFi（依賴于硬件） </p><p>　　照相機，GPS，指南針和加速度計（依賴于硬件） </p><p>　　豐富的開發(fā)環(huán)境：包括設備模擬器，調試工具，內存及性能分析圖表，和Eclipse集成開發(fā)環(huán)境插件</p><p><b>　　應用程序</b>&l

15、t;/p><p>　　Android會同一個核心應用程序包一起發(fā)布，該應用程序包包括email客戶端，SMS短消息程序，日歷，地圖，瀏覽器，聯(lián)系人管理程序等。所有的應用程序都是用Java編寫的。</p><p>　　Android應用程序框架開發(fā)者也完全可以訪問核心應用程序所使用的API框架。該應用程序架構用來簡化組件軟件的重用，任何一個應用程序都可以發(fā)布它的功能塊并且任何其它的應用程序都可以

16、使用其所發(fā)布的功能塊（不過得遵循框架的安全性限制）。該應用程序重用機制使得組建可以被用戶替換。</p><p>　　以下所有的應用程序都由一系列的服務和系統(tǒng)組成，包括：</p><p>　　一個可擴展的視圖（Views）可以用來建應用程序，包括列表（lists），網格（grids），文本框（text boxes），按鈕（buttons），甚至包括一個可嵌入的web瀏覽器 </p>

17、;<p>　　內容管理器（Content Providers）使得應用程序可以訪問另一個應用程序的數(shù)據(jù)（如聯(lián)系人數(shù)據(jù)庫），或者共享它們自己的數(shù)據(jù)。 </p><p>　　一個資源管理器（Resource Manager）提供非代碼資源的訪問，如本地字符串，圖形，和分層文件（layout files）。 </p><p>　　一個通知管理器（Notification Manag

18、er）使得應用程序可以在狀態(tài)欄中顯示客戶通知信息。 </p><p>　　一個活動類管理器（Activity Manager）用來管理應用程序生命周期并提供常用的導航回退功能。</p><p><b>　　點餐系統(tǒng)</b></p><p>　　點餐系統(tǒng)利用軟件的全自動信息化手段，實現(xiàn)點菜、配菜、炒菜到傳菜的全部管理過程；完成點菜單計算機管理、點

19、菜單前端收銀臺與各廚房的同步打??；實現(xiàn)菜單無紙化操作；后臺經理查詢；倉庫進銷存管理等。</p><p>　　除此之外，點餐系統(tǒng)還可以對客戶資料進行有效的管理，存檔和備查，杜絕酒樓“漏單”、“跑單”現(xiàn)象；幫助酒樓利用計算機強大的數(shù)據(jù)處理能力和流程優(yōu)化能力，實現(xiàn)自動化管理，簡化酒樓的工作流程，減少浪費及人為管理的疏漏現(xiàn)象，重新優(yōu)化配置企業(yè)資源，把經營成本降低到最低。 </p><p>　　功能

20、強大的點餐系統(tǒng)除支持一般的單機和局域網應用之外，還支持總店/分店多級架構的遠程聯(lián)網應用于分店使用POS系統(tǒng)實現(xiàn)前臺銷售收銀、即時打印銷售小票、銷售日結、上報銷售數(shù)據(jù)和接收新菜品信息等功能。</p><p>　　目前點餐系統(tǒng)共有三種實現(xiàn)模式：</p><p>　　觸摸屏點菜模式：它利用了目前最為流行的觸摸式電腦實現(xiàn)點菜過程，即點菜員可以根據(jù)軟件的畫面提示，只需用手指點擊畫面就可以完成整個點菜

21、過程，方便快捷，這種模式適用于菜式和做法豐富大型的酒樓、酒家和菜館等。</p><p>　　無線PDA點菜模式：它利用了無線WiFi技術，通過PDA顯示點菜界面，使用觸摸筆完成點菜過程，真正實現(xiàn)隨時隨地點菜實時響應，這種模式適用于菜式和做法較為簡單的西餐廳、特色菜館和特具情調的中高級餐廳等。</p><p>　　無線點菜寶模式：它使用了ISM頻段，可以在有樓層或其它障礙物阻擋的情況下無縫覆

22、蓋達10米之遠，而信號依然穩(wěn)定，這是其比之無線PDA點菜模式最大的優(yōu)勢，這種模式適用于菜式和做法較為簡單及其它要求較少的快餐店、火鍋店等。</p><p><b>　　附件2：外文原文</b></p><p><b>　　WLAN</b></p><p>　　Why use WLAN</p><p>

23、;　　For one of the main local area network management, for the laying of cables, or check the cable is disconnected this time-consuming work, it is easy to upset, not easy to break in a short time to find out where. Furth

24、ermore, for the business and application environment constantly updating and development of enterprise network must be matched with the original re-layout, need to re-install the network lines, although the cable itself

25、is not expensive, but requested the technical staff to the high</p><p>　　What conditions need to use WLAN </p><p>　　WLAN is not limited to alternative local area network, but to make up for lack

26、 of wired local area networks, in order to achieve the purpose of extending the network, the following circumstances may have wireless local area network.</p><p>　　no fixed workplace users</p><p&g

27、t;　　wired local area network set up by the environmental constraints</p><p>　　As a wired local area network backup system</p><p>　　WLAN access technology</p><p>　　Currently manufact

28、urers in the design of wireless local area network products, there are quite a variety of access design methods can be divided into three categories: narrowband microwave, spread spectrum (Spread Spectrum) technology, an

29、d infrared have their advantages and disadvantages, limitations, and more, followed by detailed discussion of these techniques. (Infrared) technology, each technique has their advantages and disadvantages, limitations, a

30、nd more, followed by detailed discussion o</p><p>　　Technical requirements</p><p>　　As wireless local area network needs to support high-speed, burst data services, need to be addressed in the i

31、ndoor use of multipath fading, as well as issues such as crosstalk subnets. Specifically, wireless local area network must achieve the following technical requirements:</p><p>　　Reliability: Wireless LAN sys

32、tem packet loss rate should be lower than 10-5, the error rate should be lower than 10-8.</p><p>　　Compatibility: For indoor use of wireless local area network, so as far as possible with the existing wired

33、LAN network operating system and network software compatible. </p><p>　　Data rate: In order to meet the needs of local area network traffic, wireless LAN data transfer rate should be more than 1Mbps.</p&g

34、t;<p>　　The confidentiality of communications: As the data transmitted in the air via wireless media, wireless local area networks at different levels must take effective measures to improve communication security

35、 and data security.</p><p>　　Mobility: support for all mobile networks or semi-mobile network.</p><p>　　Energy Management: When receiving or sending data to the site when the machine is in sleep

36、 mode, when activated again when the data transceiver to achieve the savings in power consumption.</p><p>　　small size and low price: This is the key to the popularity of wireless local area network can be.&

37、lt;/p><p>　　Electromagnetic environment: wireless LAN should consider the humanbodyand the surrounding electromagnetic environment effects.</p><p><b>　　Android</b></p><p>　

38、　Google Android is a Linux-based platform for developing open-source phone operating system (registered trademark in China called &quot;Achi;). It includes operating systems, user interface and applications - mobile

39、phone work required by the software, but there is no past, the exclusive right to impede innovation and barriers to mobile industry, called mobile terminal is the first to create a truly open and complete mobile software

40、. Google and Open Handset Alliance to develop the Android, the al</p><p>　　It uses software stack layers (software stack, also known as the software stack) architecture, is divided into three parts: the core

41、 of the underlying Linux-based language developed by the c, only basic functions. Middle layer consists of library. Library and Virtual Machine Virtual Machine, developed by the C +. At the top are a variety of applicati

42、ons, including the call procedures, SMS procedures, application software is developed by the companies themselves to write java.</p><p>　　To promote this technology, Google, and dozens of other phone company

43、 has established the Open Handset Alliance (Open Handset Alliance).</p><p>　　Characteristic</p><p>　　application framework to support component reuse and replacement</p><p>　　Dalvik

44、 virtual machine specifically for mobile devices is optimized</p><p>　　Internal integrated browser, the browser-based open-source WebKit engine</p><p>　　optimization of 2D and 3D graphics librar

45、y includes graphics library, 3D graphics library based on OpenGL ES 1.0 (hardware-accelerated optional)</p><p>　　# SQLite for structured data storage</p><p>　　Multimedia support includes the com

46、mon audio, video and static image file formats (such as MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, GIF)</p><p>　　GSM phone (depending on hardware)</p><p>　　Bluetooth Bluetooth, EDGE, 3G, and WiFi (h

47、ardware dependent)</p><p>　　Camera, GPS, compass, and accelerometer (hardware dependent)</p><p>　　Rich development environment including a device emulator, debugger, memory and performance ana

48、lysis charts, and the Eclipse integrated development environment plug-ins</p><p>　　Applications</p><p>　　A core Android application package together with the release of the application package,

49、including email client, SMS short messaging program, calendar, maps, browser, contact management procedures. A ll applications are written using JAVA.</p><p>　　Android Application Framework Developers have f

50、ull access to core applications used by the API framework. The application framework designed to simplify the reuse of software components; any application can publish its functional blocks and any other applications can

51、 use the function block its release (but must follow the framework of security restrictions). Reuse mechanism allows the application form can be user replaced.</p><p>　　All of the following applications by t

52、he composition of a range of services and systems, including:</p><p>　　an expanded view (Views) can be used to build applications, including a list of (lists), grid (grids), text boxes (text boxes)

53、, buttons (buttons), and even an embeddable web browser.</p><p>　　Content Manager (Content Providers) allows applications to access data from another application program (such as the contact database), or to

54、 share their own data.</p><p>　　A resource manager (Resource Manager) to provide access to non-code resources, such as local strings, graphics, and hierarchical file (layout files).</p><p>　　A n

55、otification manager (Notification Manager) allows applications to customers in the status bar display notification information.</p><p>　　An activity class Manager (Activity Manager) to manage the application

56、 life cycle and provides common navigation rollback feature.</p><p>　　Ordering the system</p><p>　　Ordering the system information using automated software tools to achieve la carte, side dishes

57、, stir fry vegetables to the transfer of all management processes; completion point, the computer management menu, point the menu and the kitchen, front-end checkout synchronization print; achieved without the menu paper

58、-based operation; backstage manager of inquiry; warehouse inventory management and so on.</p><p>　　In addition, ordering the system can also effectively manage customer data, archiving and future reference,

59、put an end to the restaurant "leakage List", "run list" phenomenon; help restaurants using computer data processing capability and powerful ability to process optimization to achieve automated managem

60、ent, streamline workflow restaurant, reduce waste and man-made phenomenon of management oversight, re-optimal allocation of corporate resources, the operating costs to a minimum.</p><p>　　Powerful addition t

61、o ordering the system to support the general application of stand-alone and LAN in addition to support head office / branch of multi-level framework used for remote network using the POS system to achieve front store sal

62、es cashier, sales of small-ticket instantly print sales day-end, reporting sales data and receive information of new features dishes.</p><p>　　There are three currently ordering the system to achieve mode:&l

63、t;/p><p>　　First, the touch screen a la carte model: It uses the currently most popular touch-computer ordering process to achieve that members can to order the software screen prompts, simply click on the scre

64、en with your fingers can complete the entire ordering process and convenient This model applies to the practice of rich dishes and large restaurants, restaurants, and restaurant, etc..</p><p>　　Second,the wi

65、reless PDA ordering mode: it uses a wireless WiFi technology, a la carte interface by PDA display, use touch pen to complete the ordering process, virtually anywhere, anytime to order real-time response, this model is mo

66、re suitable for dishes and practices simple restaurant, features a restaurant and special mood of senior restaurants. Third, the wireless ordering Po mode: it uses the ISM band, can be a floor or other obstruction in