Web 2.0

1. Web 2.0 Introduction to Computing and Web Technologies 2 weeks

2. What is XML ? It is a technology primarily concerned with the description and structure of data

3. File Data Structures There are two kind of data files that are understood by computers: Binary files Text files

4. Metadata The codes inserted into the document can be considered metadata, or information about information. For example “this word shall be bold” etc. This metadata is really what differentiates one file type from another.

5. A brief history of markup The goal has been to find a universal data format An early attempt was SGML - Standard Generalized Markup Language Markup is any information that is part of a tag. <airlock id=“level1”><status>open</status></airlock> Character data Markup

6. SGML and HTML The best know application of SGML is HyperText Markup Language or HTML. HTML is a specific vocabulary for the display of information and for the linking of different pieces of information.

7. What is XML ? XML is a subset of SGML but with much of the complexity removed. Not really a language at all, but a standard for creating languages that meet the XML criteria. XML describes a syntax which you use to create your own languages.

8. XML XML is a compliment for HTML – not a replacement. In most applications, XML is used to transport data, while HTML is used to format and display the data. XML is a software – and hardware-independent tool for carrying information.

9. XML XML is now as important for the web as HTML was to the foundation of the Web. XML is the most common tool for data transmission between all sorts of applications.

10. The Basic structure of XML Trees Root, Branches and Leaves One Root Element Well Formed All elements must have matching start and end tags. All attributes must be in quotes. All elements must nest properly

11. The Basic structure of XML

12. Stylesheets To format and display the information, stylesheets are used. By combing style sheets with XML data you can separate your data from your presentation.

13. Style Sheets The two most common ways of creating style sheets are using a style sheet language called Cascading Style Sheets (CSS) and A transformation style sheet language called Extensible Style Sheet Language – Transformation (XSLT).

14. The benefits of XML Programmers structure data in an infinite variety of ways. With every new way of structuring data comes a new methodology for extracting the information we need. If the data changes, the methodologies also have to change, and testing and tweaking begin again. With XML there is a standardised way to get the information, no matter how we structure it.

15. XML Parsers There are programs, called parsers, which are able to read XML syntax and get the information out for us. These parsers can be used directly within programs, meaning applications never have to look at the XML directly.

16. Hierarchies of Information XML groups information in hierarchies. The items in a document relate to each other in parent/child and sibling/sibling relationships. Eg. <name> ________ <first> ________________”John” ________ <middle> ________________”Fitzgerald Johansen” ________ <last> ________________”Doe”

17. What is a Document Type ? A specific set elements called a vocabulary, used to mark up the data A document type is a document that is structured in a specific way using a specific vocabulary, to describe a certain type of information.

18. The Pieces that make up XML XML DTD’s and XML Schemas NameSpaces XPath CSS and XSLT

19. Exercises Find some examples of XML and explain what they do. Find some sites that use RSS feeds. Find examples of CSS from some websites.

20. Web 2.0 Monetization Models Many Web 1.0 businesses discovered that popularity (“eyeballs”) was not the same as financial success Web 2.0 companies are paying more attention to monetizing their traffic Web 2.0 monetization is heavily reliant on advertising Example: Google’s AdSense 20

21. Web 2.0 monetization models (Part 1 of 4). 21

22. Web 2.0 monetization models (Part 2 of 4). 22

23. Web 2.0 monetization models (Part 3 of 4). 23

24. Web 2.0 monetization models (Part 4 of 4). 24

25. Future of the Web Computers have a hard time deciphering meaning from XHTML content Web today involves users’ interpretations of what pages and images mean, but the future entails a shift from XHTML to a more sophisticated system based on XML, enabling computers to better understand meaning. Web 2.0 companies use “data mining” to extract as much meaning as they can from XHTML-encoded pages Tagging and Folksonomies Early hints a “web of meaning.” “loose” classification system Semantic Web Next generation in web development, “web of meaning” Depends heavily on XML and XML-based technologies Microformats Standard formats for representing information aggregates that can be understood by computers, enabling better search results and new types of applications 25

26.  Future of the Web (Cont.) Resource Description Framework (RDF) Based on XML Used to describe content in a way that is understood by computers Connects isolated databases across the web with consistent semantics Ontologies Ways of organizing and describing related items, and are used to represent semantics. Another way of cataloging the Internet 26

27. Web 2.0 news, analysis, technology and business resources. 27

28. Peer-to-Peer Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or work loads between peers. Peers are equally privileged, equipotent participants in the application. They are said to form a peer-to-peer network of nodes.

29. Peer-to-Peer Peer-to-peer was popularised by file sharing systems like Napster. The peer-to-peer computing paradigm has inspired new structures and philosophies in other areas of human interaction.

30. Peer-to-Peer There are numerous applications of peer-to-peer networks. The most commonly known is for content distribution Content delivery Many file sharing networks, including Gnutella, G2 and FastTrack. Peer-to-peer file sharing popularized peer-to-peer technologies. From 2004, it is the largest contributor of network traffic on the Internet. Peer-to-Peer Content Delivery Networks (P2P-CDN) (Giraffic, Kontiki, Ignite, RedSwoosh. Software publication and distribution (Linux, several games); via file sharing networks.

31. Peer-to-Peer Streaming media. P2PTV and PDTP. Applications include TVUPlayer, Joost, CoolStreaming, Cybersky-TV, PPLive, LiveStation Spotify uses a peer-to-peer network along with streaming servers to stream music to its desktop music player. Peercasting for multicasting streams. See PeerCast, IceShare, FreeCast, Rawflow Pennsylvania State University, MIT and Simon Fraser University are carrying on a project called LionShare designed for facilitating file sharing among educational institutions globally. Osiris (Serverless Portal System) allows its users to create anonymous and autonomous web portals distributed via P2P network.

32. Peer-to-Peer Networking Domain Name System, for Internet information retrieval. eg Comparison of DNS server software cloud computing Dalesa a peer-to-peer web cache for LANs (based on IP multicasting). Communications networks Skype, one of the most widely used internet phone applications is using P2P technology. VoIP (using application layer protocols such as SIP) Instant messaging and online chat

33. Skype Skype is a software application that allows users to make voice calls over the Internet. Calls to other users within the Skype service are free, while calls to both traditional landline telephones and mobile phones can be made for a fee using a debit-based user account system.

34. Skype Skype has also become popular for its additional features which include instant messaging, file transfer, and video conferencing. The network is operated by a company called Skype Limited, headquartered in Luxembourg and partly owned by eBay.

35. Skype • Registered users of Skype are identified by a unique Skype Name, and may be listed in the Skype directory. • Skype allows these registered users to communicate through both instant messaging and voice chat. • Voice chat allows calls between pairs of users and conference calling, and uses a proprietary audio codec. • Skype's text chat client allows group chats, emoticons, storing chat history, offline messaging and (in recent versions) editing of previous messages. • The usual features familiar to instant messaging users—user profiles, online status indicators, and so on—are also included.

36. Skype Skype is a secure communication; encryption cannot be disabled, and is invisible to the user. Skype reportedly uses non-proprietary, widely trusted encryption techniques: RSA for key negotiation and the Advanced Encryption Standard to encrypt conversations. Skype provides an uncontrolled registration system for users with no proof of identity. Instead, a free choice of nicknames permits users to use the system without revealing their identity to other users.

37. Cloud Computing Cloud computing is Internet-based development and use of computer technology. The cloud is a metaphor for the Internet, based on how it is depicted in computer network diagrams, and is an abstraction for the complex infrastructure it conceals. It is a style of computing in which IT-related capabilities are provided “as a service”. Cloud computing attracts more and more attentions from computer science researcher and entrepreneurs.

38. Why we use cloud computing?

39. Why we use cloud computing? Case 1: Write a file Save Computer down, file is lost Files are always stored in cloud, never lost

40. Why we use cloud computing? Case 2: Use IE --- download, install, use Use QQ --- download, install, use Use C++ --- download, install, use …… Get these from the cloud instead

41. What is cloud and cloud computing? Cloud computing is a style of computing in which dynamically scalable and often virtualised resources are provided as a service over the Internet. Users need not have knowledge of, expertise in, or control over the technology infrastructure in the "cloud" that supports them.

42. The architecture of cloud computing system

43. Characteristics of cloud computing Virtual: software, databases, Web servers, operating systems, storage and networking as virtual servers. On demand: add and subtract processors, memory, network bandwidth, storage.

44. Types of cloud service SaaS Software as a Service PaaS Platform as a Service IaaS Infrastructure as a Service

45. Cloud and Security The relative security of cloud computing services is a contentious issue which may be delaying its adoption. Some argue that customer data is more secure when managed internally, while others argue that cloud providers have a strong incentive to maintain trust and as such employ a higher level of security.

46. Cloud: Availability and Performance In addition to concerns about security, businesses are also worried about acceptable levels of availability and performance of applications hosted in the cloud. There are also concerns about a cloud provider shutting down for financial or legal reasons, which has happened in a number of cases.

47. Summary In this section we have looked at: Web 2.0 Content Networks Social Networking Rich Application Applications Location-Based Services Skype Cloud Computing

48. Exercise Copy the following code into a file called “test.html” <html><body><h1>My First Heading</h1><p>My first paragraph.</p></body></html> Using IE or Firefox open the file and see what you have produced. Using the website: http://www.w3schools.com/html/default.asp generate some further websites using the features of html