Lecture 1: Introduction SGN-5226 Content Sharing Technologies and Services

Transcription

1 1 Lecture 1: Introduction SGN-5226 Content Sharing Technologies and Services

2 2 About the course Focus of the course: Technologies and wider aspects of Internet services in relation to content. Multimedia content, commercial and user-generated, has been driving the transformation of the web Objective of the course: Provide an understanding of how such services are designed, developed, interlinked and maintained Knowledge valuable for working on, or further researching, this domain. High-level topics to be covered: key technologies and enablers hands-on implementation examples popular p paradigms and use cases legal, privacy and trust issues

3 3 Practicalities Course runs for 2 periods (Sept-Dec 2010) Once a week Every Thursday at TB214 in Period I (other room in Period II) We will have lectures 2-3 of them will be invited external experts from the industry Lecture attendance 70% expected (but flexible if special reasons) Small weekly exercises for home All key material in slidesets Final exam OR longer assignment (you choose) 4cr Accepted as post-graduate level Requirements: 70% attendance + 70% of exercises + (exam OR assignment) Pass/Fail grade

4 4 Practicalities All material will be available at:

5 5 About me (cc) Flickr user: Anynonymoose

6 6 Content Sharing Technologies and Services

7 7 Content Sharing Technologies and Services

8

9

10

11 Traditional distribution flow

12 Few people generate the content

13 Many consume

14 Few-to-many

15 Change

16 Content turned digital

17 ...with the introduction of digital still cameras...

18 ... Digital camcorders...

19 ... Which became cheap...

20 ...small...

21 ... Consumable products...

22 ... so almost every could afford one...

23 Change2

24 The introduction of the camera phone...

25 Even more functionality in a cheaper... Even more functionality in a cheaper offering...

26 ... Could reach even more people...

27 ... Even young people that were previously excluded.

28

29 7

30 7:1

31 7:1

32 7:1

33 As people have a media capturing device at hand...

34 ... The capture content: Of landscapes...

35 ... Of their friends...

36 ... Of themselves...

37 ... Of themselves in ridiculous poses.

38 And what do they do with this content? Share it!

39 Content Sharing Technologies and Services

40 Aristotle said (350 BC):

41 φύσει πολιτικόν ζώον (Αριστοτέλης, Πολιτικά, Α, 1253a)

42 by nature a social animal (Aristotles, Politica, Α, 1253a)

43 Maslow (1943):

44 Hierarchy of needs

45

46 Family Intimacy Friendship Communication

47 Social

48 Sharing

49 In the digital era: Stay in touch Broadcast social presence Exchange experiences

50 50 Media

51 51 Media

52 52 Media Nowadays, I would categorize also Apps as content. The threshold of generating them has gotten so low, that many (advanced) users can create and share them...

53 53 Social Media

54 54 Social Media Commenting

55 55 Social Media Commenting Tagging

56 56 Social Media Commenting Tagging Voting

57 57 Social Media Commenting Tagging Voting Rating

58 58 Social Media Landscape

59 59 Social Media Video:

60 60 Web 2.0 There is no single definition (and there will probably never be) Some think that Web 2.0 is: The assimilation of human participation into web architecture The web as a platform Business model revolution Natural progression of the Internet What the first generation of the Internet t tried to be Just a buzzword

61 61 Web 2.0 Web 2.0 is the business revolution in the computer industry caused by the move to the Internet as platform, and an attempt to understand the rules for success on that new platform. Chief among those rules is this: Build applications that harness network effects to get better the more people use them. - Tim O Reilly

62 62 Web 2.0 Generally refers to a set of: Social Architectural Design patterns Resulting in the mass migration of business to the Internet as a platform The focus is on the interaction models between: Communities People Computers Software Human interactions are important Blending human experience with technology

63 63 Web 1.0 vs 2.0

64 64 Common Web 2.0 Architecture Patterns Most of the Web 2.0 patterns can be abstracted, ranging from the most concrete to the most abstract (high-level design pattern) Abstraction example: - A company uses a PDF form to collect user input from its customers - An organization uses an electronic form to collect data from a person - An entity uses an electronically encoded artifact to convey data between other entities and itself Each statement is true and accurate. But patterns become more abstract. Keep this simple example in mind, for the Web2.0 patterns we will discuss

65 Common Web 2.0 Architecture Patterns Service-Oriented Architecture (SOA) Service Oriented Architecture (SOA) is an architectural paradigm, a way of architecting a framework for matching needs and capabilities. Key feature: integrating services that are owned and managed independently Core pattern underlying Web 2.0 on top of which other patterns rely (e.g. Mash-ups and dsoftware as a Service) Example: An application is offering an end-point/interface where consumers can invite a service and get the weather conditions in a city

66 Common Web 2.0 Architecture Patterns Software as a Service (SaaS) SaaS delivers computational functionality to users, without then having to persist the entire application or system, on their computers Applies the SOA to software, moving away from the older model of locally stored, self-contained software Web-based applications Example: allows users to turn an HTML document in PDF, without the need of installing the PDF creator on their PC. Also, Google docs allow users to edit documents on-line

67 Common Web 2.0 Architecture Patterns Participation-Collaboration Focusing on self-organizing communities and social interactions Embraces: Reuse of content Fractional updates or contributions to collective works The constant Beta culture Trusting of users Making the user core part of the architecture t and model for Web 2.0 Example: Wikipedia -> Harnessing collective intelligence

68 Common Web 2.0 Architecture Patterns Asynchronous Particle Update The core pattern behind Asynchronous JavaScript and XML (AJAX) Instead of forcing a complete object (e.g. page view) update, a smaller part of the whole can be updated asynchronously. Updates could be triggered by timeouts, user activity, changes in state, or present parameters. Example: Twitter real-time results

69 Common Web 2.0 Architecture Patterns Mash-up Aggregating content or computational resources from multiple sources, and mixing them together to create something new Typically, two of more applications/services appear working together Example: Showing bus information on Google Maps

70 Common Web 2.0 Architecture Patterns Rich User Experience (RUE) Is the replication of the complete, real-world interaction, between two entities, rather than some part of the interaction Combining several aspects, such as: Visual Presentation Contextually relevant information Applications modeled to understand the complete scope of possible interactions between users and software

71 Common Web 2.0 Architecture Patterns The Synchronized Web Multiple applications or users share the same state or view of the same state Typically in online games, but has evolved far beyond Essential pattern that supports multiple forms of interactions, including: Request/response Subscribe/push Probe and match Pull

72 Common Web 2.0 Architecture Patterns Collaborative Tagging Referred as folksonomy : the ability of users to add labels (or tags ) to link resources with semantic symbols Major top-down efforts to create a semantic web have failed, while Collaborative Tagging g has added a new aspect to the creation of common schematic layer for the Internet Example: where users can apply labels to public bookmarks

73 Common Web 2.0 Architecture Patterns Declarative Living and Tag Gardening In real world people make statements about just about everything Declarative Living: the act of encoding those declarations in syntax that a machine can process, and making them visible to other entities on the web Tag Gardening: harvesting the declarations to learn about users collective state Example: Twitter where users make declarations about their daily activities. Even Facebook where people simply declare existing social structures (i.e their list of friends), are a specialized form of this pattern

74 Common Web 2.0 Architecture Patterns Schematic Web Grounding This pattern assembles interactions that monitor the links between declarations (e.g. semantic tags ) and resources, as well as how users interact based on those artifacts Facilitates self-learning, self-healing software, as observing the patterns of interactions can lead to inferences about the relevancy of semantic declarations. Example: Adaptive learning software systems, and Google Search

75 Common Web 2.0 Architecture Patterns Persistent Rights Management A pattern of users retaining their Create, Read, Update, Delete (CRUD) rights on every copy of a digital artifact. As opposed to simply securing the location of the original copy, this pattern bestows authors rights on all copies of a work Not to be confused with Digital Right Management (DRM), which is only a subset of this pattern. DRM is addressing only read access to digital files Persistent Right Management is finer-grained. Control over: printing, viewing, modifying and more. Example: Adobe LiveCycle Rights Management Server and Microsoft s Rights Management Server

76 Common Web 2.0 Architecture Patterns Structured Information The advent of XML and the ability to apply customized tagging to specific elements has lead to the rise of syntaxes commonly referred as microformats Small formats with highly specialized abilities to mark up precise information within documents. Enables users to address content at a much more granular level than ordinary HTML. Example: XML Friends Network (XFN)

77 77 Architectural Patterns Patterns are abstract designs that may be applied to multiple and diverse manifestations of a common problem. They can be expressed in many formats, however, they generally include three basic elements 1.A problem 2.A context in which the problem occurs 3.The solution to the problem Example: Consider a pattern that captures the concepts of pants. Have: Legs Pockets Etc. But different materials (based on requirements) Example: YouTube = Participation-Collaboration, Semantic Web Grouping

78 78 Architectural Patterns While a pattern describes functionality shared across any number of implementations, patterns can evolve over time and adjust to meet different needs As a general rule, the higher level of abstraction of a pattern is, the more it can be repurposed Finding patterns involves examining i case after case, looking for commonalities

79 79 Guiding Architecture

80 80 The core of the Internet It makes sense to examine the foundation, the Internet, from an architectural perspective and ask some architectural questions. The Internet is comprised of a series of interconnected devices, computers, and networks that interoperate via a set of protocols and standards governing their externally visible behavior. One could describe the Internet t as a platform or large bus that t allows multiple patterns of interaction

81 81 The Internet Fuses multiple disparate networks into one cohesive network Based on open standards (TCP/IP, HTTP, TLS/SSL, etc) and HTML, CSS, JavaScript

82 82 Open Standards Open standards generally have the following characteristics: They re not controlled by any one private entity, and they can t be changed at the will of any one entity without an input process that facilitates consideration of the points of view and input of others. They re developed by organizations that are operating with an open and transparent t process, allowing stakeholders to have a say in their development. They re not loaded by patents or other intellectual property p claims that result in unfair distribution of the ability to implement them, whether for commercial or noncommercial purposes. They re designed to benefit the whole community of users rather than one specific subset of users for financial or other gains.

83 83 Basic Communications: TCP/IP The Transmission Control Protocol (TCP) and Internet Protocol (IP), often grouped together as TCP/IP, are two of the core technology standards upon which the Internet relies. TCP/IP is a low-level protocol that ensures that signals can be moved from one place to another. IP moves packets of data from one point to another, with routers helping those packets find their way across networks. The Hypertext Transfer Protocol (HTTP) works as a layer on top of TCP/IP

84 84 Conversations: HTTP and More HTTP is a text-based messaging protocol that piggybacks on TCP/IP and handles the actions required for web browsers to interact with web resources. The HTTP specification defines eight core methods, the best known of which are GET and POST, commonly used to request information and submit information through forms. Most of the methods are variations on the theme of sending a request object containing some bytes and receiving a response object One key feature of HTTP is that it is a stateless protocol. There is nothing in the protocol itself that establishes connections between multiple requests. Each incoming HTTP request is treated uniquely and individually, and the web server itself doesn t need to know of any other previous requests that the same client may have made.

85 85 Conversations: HTTP and More Changes over the last decade have left the basic infrastructure of HTTP intact but made it possible to use it in new and transformative ways. It isn t always necessary to change the underpinnings of a system to be able to evolve it in unexpected directions. AJAX, introduction of an asynchronous communication revolution. It still uses HTTP, but instead of having to refresh the entire page, it supports a pattern of incrementally updating only a small facet of an information set. Developers started exploring a range of possibilities that didn t necessarily involve web browsers. Called web services, these technologies use HTTP to share information across a wide variety of programs and environments E.g. REST relies on the GET, PUT, POST, and DELETE methods already present in HTTP to build a simple but powerful Create, Read, Update, and Delete(CRUD) interface. REST:

86 86 Security As the Internet has grown up, many requirements for controlling access to information and functionality have manifested as a set of standards to address security concerns. The Secure Sockets Layer, otherwise known as SSL secure pipes upon which to transmit data as a layer via the Internet. The protocol utilizes a cryptographic system of two keys to encrypt and decrypt data. By convention, URLs that require an SSL connection start with instead of Transport Layer Security, or TLS is a dual-layered model wherein the first layer, the record protocol, piggybacks upon a reliable transport protocol and ensures that the connection is not eavesdropped upon by using a technique known as symmetric data encryption. The next layer, the handshake protocol, allows authentication between the server and client and the negotiation of an encryption algorithm and cryptographic keys before the application protocol transmits or receives any data.

87 87 Content: Text and data While the technologies for transferring information across the Internet have evolved relatively slowly, technologies for describing content have sprouted rapidly since the inception of the Web HTML created an open format for sharing information between humans. Humans (or their tools) could use HTML to create documents that humans (through their browsers)could read. That worked well, unless you needed to send information from computer to computer. In 1998, Extensible Markup Language (XML): While XML was originally meant to be a replacement for (or at least a supplement to) HTML as hypertext t on the Web, it settled instead into a role of a format for exchanging data between programs and became a key component of web services. Feeds: For describing lists. RSS & Atom (we will introduce later)

88 88 Content: Presentation and scripting Web browsers typically support two layers of additional functionality for making the textual data visually interesting and more interactive: styles and scripting. A style, usually provided by Cascading Style Sheets (CSS), supplies the color, layout, fontography, and more for documents. Much of this used to be done in HTML directly, but separating the presentation information makes it much easier to create attractive and flexible styles for many documents at once. Changing a background color across a site shouldn t require visiting every page on the site and changing it there. Scripting, usually provided d by JavaScript, lets web developers create interfaces that respond more directly to user requests. Scripting can capture user interactions with a page and modify the HTML document or the style sheet for the page in response.

89 89 Content: Graphics & Multimedia Graphics: Formats(JPEG, GIF, PNG, SVG) come and go, and a few new features (such as animation and transparency) have been introduced along the way, but graphics have mostly stayed within the same general parameters inside of web pages. Multimedia: Plug-ins most notably Adobe s Flash provided an alternative approach for supporting fast animation, more interactivity, and more control over features such as video and sound. (Plug-ins like QuickTime and RealPlayer supported particular audio and video formats, but Flash has remained more versatile.) Rich Internet t Applications (RIAs) often include Flash, Silverlight, li or similar il plug-ins to create a more interactive experience than is easily done within the browser itself.

90 90 On a happy and funny conclusion... Try this Rich User Experience example A hunter shoots a bear! P.S. Don t forget the homework 1 for next week!

91 91 References This lecture has been based on material from : James Governor, Dion Hinchcliffe, Duane Nickull, Web 2.0 Architectures, O'Reilly Media, May