云就算在教育中的應(yīng)用

1、Cloud computing for education: Anew dawn?AbstractEducational establishments continue to seek opportunities to rationalize the way they manage their resources. The economic crisis that befell the world following the near collapse of the global financial system and the subsequent bailouts of local ban

2、ks with billions of tax payerswill continue to affect educational establishments that are likely to discover that governments will have less money than before to invest in them. It is argued in this article that cloud computing is likely to be one of those opportunities sought by the cash-strapped e

3、ducational establishments in these difficult times and could prove to be of immense benefit (and empowering in some situations) to them due to its flexibility and pay-as-you-go cost structure. Cloud computing is an emerging new computing paradigm for delivering computing services. This computing app

4、roach relies on a number of existing technologies, e.g., the Internet, virtualization, grid computing, Web services, etc. The provision of this service in a pay-as-you-go way through (largely) the popular medium of the Internet gives this service a new distinctiveness. In this article, some aspects

5、of this distinctiveness will be highlighted and some light will be shed on the current concerns that might be preventing some云計(jì)算在教育中的應(yīng)用迎來(lái)新的曙光摘要： 教育機(jī)構(gòu)一直在尋找如 何更加合理的管理教學(xué)資源。經(jīng)濟(jì) 危機(jī)使全球經(jīng)濟(jì)系統(tǒng)臨近瓦解，隨 后地方銀行使用納稅人數(shù)以?xún)|計(jì)的 錢(qián)對(duì)其支援，隨之而來(lái)的是教育機(jī) money 構(gòu)發(fā)覺(jué)政府對(duì)其的投資比之前要縮 減。本文要論述的是在這樣的困難 時(shí)期，對(duì)于缺乏現(xiàn)金支持的教育機(jī) 構(gòu)來(lái)說(shuō)，云計(jì)算有可能成為其尋找 的機(jī)會(huì)之一，它的彈性

6、和按需支付 的費(fèi)用結(jié)構(gòu)將給教育機(jī)構(gòu)帶來(lái)巨大 的經(jīng)濟(jì)利益（在授權(quán)的情況下） 。云 計(jì)算是為交付計(jì)算服務(wù)提供的一種 新型計(jì)算規(guī)范。這種計(jì)算方法依賴(lài) 于大量的現(xiàn)存技術(shù)， 例如，互聯(lián)網(wǎng)、 虛擬化、網(wǎng)格計(jì)算、Web 服務(wù)等等。 按需支付服務(wù)通過(guò)大量通用的互聯(lián) 網(wǎng)媒介給這項(xiàng)服務(wù)賦予一種新的特 殊性。在本文中，這種特殊性的一 些方面將重點(diǎn)強(qiáng)調(diào)，并說(shuō)明了涉及organizations from adopting it.Keywords: Cloud computing Web services Virtualization Grid computing Small and medium enterprises

7、 (SMEs)IntroductionProviding software as a service is not a new computing practice.Some companies, known as Application Service Providers (ASPs), were providing businesses with software programs as a service via the medium of the Internet during the 1990s. However, such attempts at “ utility computi

8、ng ” did not take off. This was largely attributed to lack of sufficient bandwidth. During that period broadband was neither cheap nor plentiful enough for utilities to deliver computing services with the speed and reliability that businesses enjoyed with their local machines (Carr, 2009). Then came

9、Web services (especially those based on the XML-based SOAP1 message protocol) that represented a model of software delivery based on the notion that pieces of software applications can be developed and then published to a registry where they can be dynamically discovered and consumed by other client

10、 applications over different transport protocols (e.g., HTTP, TCP/IP, etc.) irrespective of the language used to develop those applications or the platforms (e.g., operation systems, Internet servers) on which they are 到防止一些組織采納它的方面。關(guān)鍵詞： 云計(jì)算， Web 服務(wù)， 虛擬化，網(wǎng)格計(jì)算，中小型企業(yè) （SMEs）1、概述 提供軟件作為一種服務(wù)已不是 新的計(jì)算實(shí)踐了。

11、20世紀(jì) 90 年代， 一些以應(yīng)用服務(wù)供應(yīng)商而著名的公 司通過(guò)互聯(lián)網(wǎng)這個(gè)媒介將軟件程序 作為一種服務(wù)開(kāi)始提供。然而，并 沒(méi)有脫離“效用計(jì)算”。這主要是由 于缺乏足夠的帶寬。當(dāng)時(shí)，帶寬既 不能廉價(jià)獲取，也不能像企業(yè)使用 本地設(shè)備一樣，滿(mǎn)足實(shí)用工具能夠 高速而可靠地傳遞計(jì)算服務(wù)（ Carr， 2009）。隨之 Web 服務(wù)（特別是基 于可擴(kuò)展標(biāo)記語(yǔ)言的 SOAP信息協(xié) 議）代表著軟件應(yīng)用的一部分 基于概念的軟件傳遞模式能夠得以 開(kāi)發(fā)，并且基于不同傳輸協(xié)議 （如， HTTP, TCP/IP等）的其他客戶(hù)應(yīng)用程 序能夠發(fā)現(xiàn)和使用他們，不用考慮implemented. This was a dramat

12、ic improvement over the services provided by ASPs which relied on proprietary (and hence un-portable) software.The advent of Web services promised many exciting possibilities. Some of these promised possibilities initially received a great deal of attention and were a frequent subject of media discu

13、ssions and futuristic scenarios (sometimes amounting to “ hype”) such as the ability to automate the process of discovery, binding, and invocation of Web services on the Internet without human intervention (Manes, 2004; Nakhimovsky & Myers, 2004). One technology analyst and author (David Chappell) i

14、n 2003 even doubted if there was a business case for Web services (Chappell, 2003).However, Web services are nowhere near achieving the full potential that was hoped for. Nevertheless, the technology is being implemented successfully (and commercially) by many of the big players such as eBay, Amazon

15、 and Google (Iskold, 2006). Furthermore, the technology has also created the foundation for a new Enterprise Application Integration (EAI) paradigm known 用于開(kāi)發(fā)應(yīng)用程序的語(yǔ)言或他們運(yùn) 行的平臺(tái)（如，操作系統(tǒng)，因特網(wǎng) 服務(wù)器）。這種信任所有 （因此包括 非便攜的）軟件的 ASP提供的服務(wù) 有了戲劇性的改善。Web 服務(wù)的出現(xiàn)使許多的不可 能變?yōu)榱丝赡堋Ｗ畛踹@受到了大量 的關(guān)注，并成為了媒體頻繁討論的 話(huà)題，未來(lái)的情境（不排除“炒作”） 能夠沒(méi)

16、有人的介入因特網(wǎng) Web 服 務(wù)的調(diào)用能夠自動(dòng)發(fā)現(xiàn)進(jìn)程、連接 （ Manes,2004;Nakhimovsky & Myers,2004）。一個(gè)技術(shù)分析家兼作 者（David Chappel）l 2003 年甚至懷 疑是否這是一項(xiàng)有關(guān) Web 服務(wù)的 商業(yè)案例（ Chappell，2003）。然而， Web 服務(wù)并沒(méi)有像我們 所期待的那樣發(fā)揮出全部的潛力。 然而，這項(xiàng)技術(shù)正在被許多大的玩 家所成功的實(shí)現(xiàn)，例如 eBay，亞馬 遜，谷歌（ Iskold，2006）。此外， 技術(shù)也能夠?yàn)樾碌钠髽I(yè)應(yīng)用集合as Service-Oriented Architecture (SOA). The exte

17、nsible XML-based nature of SOAP has enabled many organizations to expose some of their legacy and disparate systems as Web services in order to achieve total integration of their systems (Clark, 2007; Flinders, 2007; Mohamed, 2007).Most importantly, SOAP-basedWebservices arenowbeing used in the deli

18、very of some aspects of a new computing paradigm (namely cloud computing) which not only promises to deliver software remotely but also other computing-related functionality thanks also to other relatively new technologies such as virtualization2 and grid computing.3What is cloud computing? There se

19、ems to bemany definitions of cloud computing around. A study by McKinsey (the global management consulting firm) found that there are 22 possible separate definitions of cloud computing. In fact, no common standard or definition for cloud computing seems to exist (Grossman, 2009; Voas & Zhang, 2009)

20、. A more commonly used definition describes it as clusters of distributed computers (largely vast data centers and server farms) which provide on-demand resources and services over a networked medium (usually （EAI）范例打造基礎(chǔ)，如面向服務(wù) 架構(gòu)（ SOA）。SOAP 可擴(kuò)展的基于 XML的特性作為 Web 服務(wù)能夠使許 多組織機(jī)構(gòu)展示一些他們的難以維 護(hù)及不同的系統(tǒng)，從而達(dá)到系統(tǒng)的

21、完全集成（ Clark， 2007；Flinders， 2007；Mohamed，2007）。最重要的是，基于 SOAP的 Web 服務(wù)用來(lái)一種新的計(jì)算模式（即云 計(jì)算）的某些方面的遞送，而不僅 承諾遠(yuǎn)程遞送軟件，還有其他與計(jì) 算相關(guān)的功能，這便不能忽視如虛 擬化及網(wǎng)格計(jì)算這些新技術(shù)。2、什么是云計(jì)算？ 現(xiàn)在似乎有許多有關(guān)云計(jì)算的 定義。 Mckinsey（一個(gè)全球企業(yè)管 理咨詢(xún)公司）的一項(xiàng)研究發(fā)現(xiàn)可能 有 22 種云計(jì)算的定義。 實(shí)際上， 并 沒(méi)有一個(gè)通用的標(biāo)準(zhǔn)或定義來(lái)定義 云 計(jì) 算 （ Grossman ， 2009 ； Voas&Zhang，2009）。一個(gè)較為普遍 的定義將云計(jì)算描述

22、為作為分布式the Internet). The term “ cloud”was probably inspired by IT text books illustrations which depicted remote environments (e.g., the Internet) as cloud images in order to conceal the complexity that lies behind them.However, by understanding the type of services offered by cloud computing, one b

23、egins to understand what this new approach is all about. The following is a list of the three main types of services that can be offered by the cloud4:? Infrastructure as a Service (IaaS): Products offered via this mode include the remote delivery (through the Internet) of a full computer infrastruc

24、ture (e.g., virtual computers, servers, storage devices, etc.);? Platform as a Service (PaaS): To understand this cloud computing layer one needs to remember the traditional computing model where each application managed locally required hardware, an operating system, a database, middleware, Web ser

25、vers, and other software. One also needs to remember the team of network, database, and system management 計(jì)算機(jī)（大規(guī)模的數(shù)據(jù)中心和服務(wù) 器群）的集群通過(guò)網(wǎng)絡(luò)媒介（通常 為因特網(wǎng)）提供按需服務(wù)的資源和 服務(wù)?！霸啤边@個(gè)詞可能是受 IT 文 字書(shū)籍的插畫(huà)靈感，描述了云圖遠(yuǎn) 程環(huán)境（如互聯(lián)網(wǎng)）掩蓋其背后的 復(fù)雜性。然而，了解云計(jì)算所提供的服 務(wù)類(lèi)型，便可開(kāi)始理解這種新方法 的全部?jī)?nèi)容。下面是云提供服務(wù)的 三種主要類(lèi)型：基礎(chǔ)設(shè)施即服務(wù)（ IaaS）：通 過(guò)這種方式提供產(chǎn)品，包括一個(gè)完 整的計(jì)算機(jī)

26、基礎(chǔ)設(shè)施（如虛擬計(jì)算 機(jī)，服務(wù)器，存儲(chǔ)設(shè)備等）的遠(yuǎn)程 遞送（通過(guò)互聯(lián)網(wǎng)）；平臺(tái)即服務(wù) （PaaS）：要想理 解云計(jì)算的這個(gè)層面，那么一方面 需要記住傳統(tǒng)計(jì)算模型中，每個(gè)應(yīng) 用程序分別負(fù)責(zé)管理的本地所需的 硬件、操作系統(tǒng)、數(shù)據(jù)庫(kù)、中間件、 Web 服務(wù)器和其他軟件。另一方面experts that are needed to keep everything up and running. With cloud computing, these services arenowprovided remotely by cloud providers under this layer;? Softwa

27、re as a Service (Saas): Under this layer, applications are delivered through themediumof the Internet as a service. Instead of installing and maintaining software, you simply access it via the Internet, freeing yourself from complex software and hardware management. This type of cloud service offers

28、 a complete application functionality that ranges from productivity (e.g., office-type) applications to programs such as those for Customer Relationship Management (CRM) or enterprise-resource management.Before proceeding any further at this stage, a word of caution is necessary. One must not assume

29、 that cloud products offered by any of the above services are likely to work out-of-the-box. In some cases they might. Google Apps, a messaging and collaboration cloud platform from Google, is probably one good example of those out-of-the-box products (even though it does require some level of confi

30、guration nevertheless). Many of the products that are offered by those three types of cloud services will require some 也要記住網(wǎng)絡(luò)、數(shù)據(jù)庫(kù)及系統(tǒng)管理 的專(zhuān)家團(tuán)隊(duì)，他們保證了一切都正 常建立和運(yùn)轉(zhuǎn)。有了云計(jì)算，云提 供商依據(jù)本層來(lái)提供這些服務(wù)； 軟件即服務(wù) （SaaS）：在這一 層，應(yīng)用程序作為一種服務(wù)通過(guò)互 聯(lián)網(wǎng)這個(gè)媒介進(jìn)行傳遞。與安裝和 維護(hù)軟件部同，你只要通過(guò)簡(jiǎn)單的 互聯(lián)網(wǎng)訪(fǎng)問(wèn)，從復(fù)雜的軟件和硬件 管理中解脫出來(lái)。這種云服務(wù)的類(lèi) 型提供了一個(gè)整的應(yīng)用程序功能， 從生產(chǎn)率（

31、如辦公類(lèi)）應(yīng)用程序到 一些客戶(hù)關(guān)系管理（ CRM）或企業(yè) 資源管理的程序。在這個(gè)階段進(jìn)行任何一步之 前，以下的注意是十分必要的。不 必假設(shè)云產(chǎn)品提供上述任何一種服 務(wù)，它有可能是即開(kāi)即用的。 Google 應(yīng)用程序、 Google 的消息傳送和合 作云平臺(tái)是很好的一個(gè)即開(kāi)即用產(chǎn) 品的例子（即使它確實(shí)需要一些配 置級(jí)別）。許多產(chǎn)品由三種類(lèi)型的云degree of programming (by the user or indeed the cloud provider) in order to access the functionality that exists in those servi

32、ces. Cloud providers will have created their own APIs (application pro-gramming interfaces) so that software developers can use them to create client applications in order to access that functionality. Currently, some of those APIs are proprietary; an issue which will be revisited later when examini

33、ng some of the limitations of cloudcomputing. However, some are based on open source standards such as SOAP or REST .To demonstrate how those services can be utilized and the processes involved in their utilization (in a very simplified manner), a hypothetical example can be given. Take, for example

34、, a typical university with an IT infrastructure that caters for the needs of students, teaching staff and management, research staff and software developers (e.g., Web developers). As illustrated in Fig. 1, demand for IT services in this environment is directed to the IT Services Department (pictur

35、ed in the middle) whose job is to:服務(wù)提供，需要一定程度的編程（用 戶(hù)或?qū)嶋H的云提供商）來(lái)訪(fǎng)問(wèn)現(xiàn)有 服務(wù)的功能。云提供商將創(chuàng)建他們 自己的應(yīng)用程序接口，從而軟件開(kāi) 發(fā)者能夠使用它們?nèi)?chuàng)建客戶(hù)端應(yīng) 用程序來(lái)訪(fǎng)問(wèn)這些功能。目前，一 些應(yīng)用程序接口是私有的；當(dāng)測(cè)試 云計(jì)算的局限性時(shí)將重新審查的問(wèn) 題。然而，一些應(yīng)用程序接口是基 于開(kāi)源標(biāo)準(zhǔn)的，如 SOAP和 REST。為了展示如何利用這些服務(wù)并 且了解如何利用的過(guò)程（用一個(gè)非 常簡(jiǎn)化的方式），我們給出了一個(gè)假 設(shè)的例子。例如，一個(gè)典型的擁有 IT 基礎(chǔ)設(shè)施的大學(xué)為學(xué)生、教職工 和管理者，研究院及軟件開(kāi)發(fā)者提 供所需（

36、如 Web 開(kāi)發(fā)商）。如圖 1 所示，在這種環(huán)境下， IT 服務(wù)需求 是針對(duì) IT 服務(wù)部門(mén)（如圖中間所示） 的，他們的工作為：圖 1 ：一個(gè)典型大學(xué)的 IT 服務(wù)主要使用者 簡(jiǎn)圖? provide students and staff with software (e.g., email accounts, operating systems, productivity applications, malware detectors and cleaners, etc.) and hardware (e.g., PCs, Servers, etc.);? provide researcher

37、s and postgraduate students with the required special software and hardware to run experiments that are likely to involve a great deal of processing and computation;? provide Web developers with the development tools needed to write and host Web applications.Many aspects of this arrangement can be m

38、igrated to the cloud as demonstrated in Fig. 2. For example, students, administrative staff and lecturers can be made to use the services of providers of SaaS and IaaS clouds. These services will be ideally accessed through thin clients.6 Any software launched by these groups of people resides on th

39、e servers of the SaaS cloud provider and is accessed online. Any requirement for disk space or additional hardware (e.g., a virtual提供給學(xué)生及教職工軟件 （如，電子郵件賬戶(hù)，操作系統(tǒng)， 生產(chǎn)率應(yīng)用程序，惡意軟件監(jiān)控器 及清理工具等）及硬件（如，個(gè)人 電腦，服務(wù)器等）；提供給研究員及碩士研究生 所需的特殊軟件和硬件，用來(lái)操作 可能包含大量的處理及計(jì)算的實(shí) 驗(yàn)；提供給 Web 開(kāi)發(fā)商編寫(xiě)及 管理 Web 應(yīng)用程序的開(kāi)發(fā)工具。各種安排的許多方面都能夠遷 移到云下，如圖

40、2 所示。例如，學(xué) 生、行政人員和講師能夠使用軟件 即服務(wù)及基礎(chǔ)設(shè)施即服務(wù)類(lèi)型的云 提供的服務(wù)。這些服務(wù)將理想地通 過(guò)瘦客戶(hù)端進(jìn)行訪(fǎng)問(wèn)。任何軟件由 用戶(hù)所在的 SaaS 云提供者的服務(wù)PC or a virtual Server) is executed immediately online by the IaaS cloud provider. The same situation applies to the developers category in this scenario. Developers can now use all the software they need for

41、 their development online and all the hardware for hosting their applications through a PaaS cloud provider. Finally, researchers whose projects require a great deal of processing power and/or additional server capacity can do so at the click of a button through an IaaS cloud provider.器啟動(dòng)，并且在線(xiàn)訪(fǎng)問(wèn)。任何桌

42、面和額外的硬件（虛擬個(gè)人電腦或虛擬服務(wù)器）需求由 IaaS云提供商在線(xiàn)即時(shí)執(zhí)行。在這個(gè)方案中，相同的情況適用于開(kāi)發(fā)商的策略。通過(guò)PaaS云供應(yīng)商，開(kāi)發(fā)者現(xiàn)在能在線(xiàn)使用所有他們開(kāi)發(fā)時(shí)所需的所有軟件及硬件托管他們的應(yīng)用程序。最后，研究員的項(xiàng)目需要具有大量處 理能力和額外服務(wù)器容量，也能夠 僅僅點(diǎn)擊按鈕便可從 IaaS云提供商那里獲得。圖 2：一個(gè)典型的大學(xué)所中使用的云計(jì)算 服務(wù)，及 IT 服務(wù)的主要使用者簡(jiǎn)圖Some analysts dispute the validity of attaching the title “ new paradigm ” to cloud computing ar

43、guing that this approach is largely dependent on existing technologies and approaches such as utility computing, distributed computing and centralized data centers. Cloud computing s only innovation,一些分析家爭(zhēng)論給云計(jì)算附上新范式”有效性，這種方式要極大的依靠現(xiàn)存的技術(shù)和方法，如效用計(jì)算、分布式計(jì)算和集中的數(shù)據(jù)中心。根據(jù)這種觀點(diǎn)，云計(jì)算僅僅according to this view, is that it combines and integrates these approaches( Weinhardt, Anandasivam, Blau, & Ster, 2009).However, the notion of providing a wide array of computingrelated services on the fly on a pay-as-you-go basis opens many opportunities for the providers of