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INTERNET STUDIES LUMSA 2016/2017 Francesca Comunello [email protected] @fcomun 2. DATA COMPRESSION LOSSY VS LOSSLESS COMPRESSION “Lossless compression is a class of data compression algorithms that allows the original data to be perfectly reconstructed from the compressed data. By contrast, lossy compression permits reconstruction only of an approximation of the original data, though this usually improves compression rates (and therefore reduces file sizes)” (Wikipedia) Lossless data compression is used in many applications. For example, it is used in the ZIP file format. It is also used as a component whitin lossy data compression technologies. It is used in machine-to-machine communication LOSSY COMPRESSION Aim: reduce source size and transmission time It is most commonly used to compress multimedia data (audio, video, and images), especially in applications such as streaming media and Internet telephony. Files or data streams contain some irrelevant information (for a particular purpose or for a specific human being: a picture may have more detail than the eye can distinguish; an audio file does not need a lot of fine detail during a very loud passage. LOSSY COMPRESSION Video can be compressed immensely (e.g. 100:1) with little visible quality loss. Audio can often be compressed at 10:1 with imperceptible loss of quality. Still images are often compressed at 10:1, as with audio, but the quality loss is more noticeable, especially on closer inspection. e.g. Jpeg (images), MPEG 4 (video), MP3 (audio), etc. (since 1995). A file created using the setting of 128 kbit/s will result in a file that is about 1/11 the size of the CD file created from the original audio source. NAPSTER Initial release: 1999 Peer-to-peer file sharing service “Napster specialized in MP3 files of music and a user-friendly interface” Legal challenges and shutdown (2001) VIDEO COMPRESSION A typical MPEG-4 lossy compression video has a compression factor between 20 and 200. Some video compression schemes typically operate on square-shaped groups of neighboring pixels (macroblocks). These blocks of pixels are compared from one frame to the next, and the video compression codec sends only the differences within those blocks. 3. COMMUNICATION PROTOCOL ‘In telecommunications, a communications protocol is a system of rules that allow two or more entities of a communications system to communicate between them to transmit information via any kind of variation of a physical quantity’ (source: wikipedia). Systems typically use a set of cooperating protocols, sometimes called a protocol family or protocol suite (e.g. TCP/IP protocol suite). WHY IS THE TCP/IP SUITE RELEVANT? First, it became a “de facto” standard allowing for worldwide network interoperability It is an ef ficient protocol (it does not always happen that the “best” standard wins market competition, e.g.: VHS vs Betamax) It is not a “proprietary” standard It is at the core of the rapid spred of the internet TRANSMISSION CONTROL PROTOCOL (TCP) AND THE INTERNET PROTOCOL (IP) TCP/IP provides end-to-end connectivity specifying how data should be packetized, addressed, transmitted, routed and received at the destination. TCP IP THE INTERNET PROTOCOL (IP) The internet layer has the responsibility of sending packets across potentially multiple networks. Internet working requires sending data from the source network to the destination network. This process is called routing. The Internet Protocol (IP) performs two basic functions: Host addressing and identification: it is accomplished with a hierarchical IP addressing system. Packet routing: the basic task of sending packets of data from source to destination by forwarding them to the next network router closer to the final destination. THE INTERNET PROTOCOL (IP) Routers forward data packets The routers keep making these best effort routing decisions until the packet reaches its destination. THE TRANSMISSION CONTROL PROTOCOL (TCP) The TCP is a connection-oriented protocol that addresses numerous reliability issues in providing a reliable byte stream: - data arrives in-order data has minimal error (i.e. correctness) duplicate data is discarded lost or discarded packets are resent includes traffic congestion control. COMPUTING EVOLUTION Evolution Human - computer interaction MAINFRAME COMPUTING (1940-1980) One computer, many users PERSONAL COMPUTING (1980-2000) One user, one computer PERVASIVE COMPUTING (2000 - now ) One user, many computers 1. MAINFRAME COMPUTING Used in large institutions Proprietary operating system Execute many programs concurrently Image: ENIAC computer (1946 – 1955) Additional reference: The imitation game (2014) (Alan Turing) MOORE LAW (1970) Processor speed, or overall processing power for computers, will double every two years. 2. PERSONAL COMPUTING 1973: the Xerox Alto, developed at Xerox PARC in 1973 (it uses a mouse, the desktop metaphor, and a graphical user interface (GUI). 1984: the Macintosh (Apple) was the first successful mass-market mouse-driven computer with a graphical user interface or 'WIMP' (Windows, Icons, Menus, and Pointers). COMMAND LINE INTERFACE USER-FRIENDLY INTERFACE (WIMP) 16/10/10 GUI: GRAPHIC USER INTERFACE WIMP (Windows, Icons, Menu, Pointing device) QWERT Y keyboard, mouse Direct manipulation of the dataspace The pointer represents the user on the screen: a virtual Doppelgänger (alter ego) The user get visual feedbacks. USER FRIENDLY INTERFACE Users cognitive resources can be used to accomplish other tasks DEFINING INTERFACE (JOHNSON) “Software that shapes the interaction between user and computer”. Computer as a symbolic system Space to be explored Humans – Machines interaction (Norman) “We are analog beings trapped in a digital world , and the worst part is, we did it to ourselves. ” Machines do better with digital encoding . The problem comes about in the form of interaction between people and machines . People do best with signals and information that fit the way they perceive and think, which means analogous to the real world. Machines do best with signals and information that is suited for the way they function, which means digital, rigid, precise. So when the two have to meet, which side should dominate? Reference: Norman, D. A . “The invisible computer ”, MIT Press, 1997. MACHINE PERSPECTIVE PEOPLE MACHINE Unclear Accurate Disorganized Organized Inattentive Attentive Emotional Unemotional Illogical Logical HUMAN PERSPECTIVE PEOPLE MACHINE Creative Accurate Tolerant Severe Attentive to change Insensitive to changes Talented Without imagination MULTITOUCH AND “NUI” (NATURAL UI) 26 SPEECH RECOGNITION Siri: voice command https://www.youtube.com/watch?v=8ciagGASro0 TOUCH USER INTERFACE MOTION DETECTION Nintendo Wii HUMAN COMPUTER INTERACTION (HCI) Human–computer interaction (HCI) researches the design and use of computer technology, focusing particularly on the interfaces between people (users) and computers. Researchers in the field of HCI both observe the ways in which humans interact with computers and design technologies that lets humans interact with computers in novel ways. (Source: Wikipedia) HUMAN COMPUTER INTERACTION (HCI) 2 main terms: functionality and usability Functionality of a system is defined by the set of actions or services that it provides to its users . Usability of a system with a certain functionality is the range and degree by which the system can be used efficiently and adequately to accomplish certain goals for certain users. Source: Karray et al. 2008 3. PERVASIVE/UBIQUITOUS COMPUTING Term created by Mark Weiser (1988) at Xerox Park. Embedding microprocessors in everyday objects so they can communicate and share information. Mobile trend: pervasive computing devices are completely connected and constantly available. Some devices: PDA , smart phones, notebook, tablet, etc. THE INTERNET THE INTERNET: A DEFINITION “Internet refers to the global information system that (i) is logically linked together by a globally unique address space based on the Internet Protocol (IP) or its subsequent extensions/follow -ons; (ii) is able to support communications using the Transmission Control Protocol/Internet Protocol (TCP/IP) suite or its subsequent extensions/follow -ons, and/or other IP-compatible protocols; (iii) provides, uses or makes accessible, either publicly or privately, high level services layered on the communications and related infrastructure described herein. Federal Networking Council (FNC) - 1995 THE INTERNET CULTURE (CASTELLS, 2001) It is characterized by a four-layer structure: the techno-meritocratic culture; the hacker culture; the virtual (online) communitarian culture; the entrepreneurial culture. THE PC CULTURE The Pirates of Silicon Valley Documentary APPLE AND MICROSOFT a THE WEB The World Wide Web functions as a layer on top of the Internet. The Web is an information space that can be accessed through the Internet. Web Pages are connected by links and can be explored using a browser (Firefox, Chrome, Safari, etc.) . TIM BERNERS LEE AND THE WEB 1991: Tim Berners-Lee invents the World Wide Web. 1993: Marc Andreessen creates predecessor to Netscape browser (Mosaic). "I just had to take the hypertext idea and connect it to the TCP Protocol and Domain Name System ideas and – Ta-da! – the World Wide Web!” (Tim Berners-Lee) THE WEB Three essential technologies: a system of globally unique identifiers for resources: uniform resource locator ( URL); the publishing language HyperText Markup Language (HTML); the Hypertext Transfer Protocol ( HTTP). Source: T. Berner s Lee, Weaving the Web (1999) URL Each Internet URL (e.g. www.google.com) corresponds to an IP address (173.194.44.49). Let’s try! THE WEB WWW Hypertext idea + Internet protocols - TCP/IP (early70) - DNS (early 80) + HTTP HTML URL BROWSER (since 1990-91) DIGITAL MEDIA HISTORY: 1960-2000 1969 DOD’s ARPAnet, predecessor of the Internet 1970s Email is developed 1976 Steve Jobs and Steve Wozniak, co -founders of Apple Computer, Inc. 1981 IBM PC is introduced 1982 CDs are introduced 1985 Microsoft Windows is launched 1989 Compaq laptop computer is launched 1991 Tim Berners-Lee invents the World Wide Web 1993 Marc Andreessen creates predecessor to Netscape browser 1995 Amazon.com launches online shopping 1997 DVDs replace VHS format NETWORK TOPOGRAPHY Some examples: 1) traf fic control systems; 2) the Internet; 3) bitTorrent 2 LOGICS WEB EVOLUTION Web 1.0 – Connecting information Web 2.0 – Connecting people Web 3.0 – Connecting the physical world Web 1.0 – Connecting information Try to use the Internet archive: Wayback machine https://arc hive.org/w eb/ Web 2.0 – Connecting people (2004) “Is all about harnessing collective intelligence using the web as a Platform” (Tim O’Reilly, 2004) es. Google, Amazon, Wikipedia, eBay, craigslist, YouTube, Facebook and Twitter. 16/10/10 Web 2.0 – o’reilly (2005) Web 2.0 is the network as platform, spanning all connected devices. Web 2.0 applications are those that make the most of the intrinsic advantages of that platform: delivering software as a continually -updated service that gets better the more people use it; consuming and remixing data from multiple sources including individual users, while providing their own data and services in a form that allows remixing by others; creating network effects through an “architecture of participation”; going beyond the page metaphor of Web 1.0 to deliver rich user experiences. WEB 2.0 Users add value Examples? WEB 2.0: THE POWER OF REVIEWS TAGGING 16/10/10 WEB 1.0 VS WEB 2.0? Tim Berners-Lee: "Web 1.0 was all about connecting people. It was an interactive space, and I think Web 2.0 is of course a piece of jargon, nobody even knows what it means. If Web 2.0 for you is blogs and wikis, then that is people to people. But that was what the Web was supposed to be all along.” (2006) “The essential difference between Web 1.0 and Web 2.0 is that content creators were few in Web 1.0 with the vast majority of users simply acting as consumers of content, while any participant can be a content creator in Web 2.0 and numerous technological aids have been created to maximize the potential for content creation. (Cormode and Krishnamurthy, 2008) THE COMPUTER FOR THE 21ST CENTURY M. Weiser, 1991 Invisible technology Ubiquitous computing vs virtual reality? Examples? Web 3.0 – Connecting the physical world The Web meets the World Some traits: Real time Mobile Sentient Social A video (Intel) 57 58 Web squared (Battelle, o’reilly, 2009) The smartphone revolution has moved the Web from our desks to our pockets. Collective intelligence applications are no longer being driven solely by humans typing on keyboards but, increasingly, by sensors. Our phones and cameras are being turned into eyes and ears for applications; motion and location sensors tell where we are, what we’re looking at, and how fast we’re moving. Source: http://www.web2summit.com/web2009/public/sched ule/detail/10194 WEB EVOLUTION z a WEB EVOLUTION z