current trends in information technology

Intelligence, Agents and Multimedia GroupUniversity of Southampton

Current Trends in Information Technology

Paul Lewis

[email protected]

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Aims and Unit Synopsis:

• To develop a knowledge of some broad issues in computing and IT which are of current interest and of potential benefit and to enhance the students’ skill in applying some of the latest technology.

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Learning Outcomes:On successful completion of the unit the students should be

able to: • develop a web site using a web site authoring package• use scripts to develop dynamic web pages• understand some of the basic principles and jargon associated with some of the following topics information retrieval knowledge processing software agents object technology multimedia information handling communications and networks

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Syllabus

This course is an awareness course covering avariety of issues in Information Technologyincluding such topics as :• The World Wide Web• AI and Knowledge Processing• Agents and Agent technology• Object Oriented approaches to software engineering• Information retrieval and Multimedia information handling• Communications and Networks

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Assessment:

• The unit will be assessed completely by coursework, for example by a project to develop a modest but dynamic web site relevant to some other aspect of the degree course and an essay on a particular topic in IT.

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Format

• Each week we will have two lectures

followed by lab sessions in

Building 44 Room 1061

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Telecommunications and Networks

• World telecommunications network Largest man-made system Technology and services evolving rapidly• Facilities for linking computers Data volumes increasing Data transfer rates increasing Multimedia systems

(text/images/speech/video) require high bandwidth

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• Early computers all stand alone

• Direct inter computer communications has led to

electronic mail

bulletin boards

news services

distributed computer systems

the web and information sharing

electronic funds transfer

e-medicine

e-commerce

e-shopping

e-banking

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At the computer system level

Initially new types of system evolved• File systems became distributed or single systems shared by several

processors• Facilities for file transfer• Facilities for remote login• Facilities for automatic interaction between systems• Daemons to handle message passing over networksNow Ubiquitous / pervasive wirelessly interlinked computingcomputers embedded into the environment eg kitchen devices with

internet connectivity/ mobile computing eg on mobiles

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Common Types of Network Configuration

• Broadcast networks

• Token Ring

• Point to point links

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Broadcast Networkse.g. Ethernet

• Any computer on the net can send a message at any time

• message contains destination address

• Each computer checks all messages and picks up its own

• messages can collide and become garbled

• Sending systems detect this and rebroadcast after a random

short time

• If traffic is high, extra collision traffic may saturate the network

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Token Ringe.g. Fibre distributed data interface (FDDI)

• Message token is passed around the ring• A computer can only transmit when it has the

token• Avoids collisions• There is performance reduction in large rings• Network fails totally if there is a break

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Point to Point Links

• Only two end points involved

• Some wide area networks (WANs) are connected this way

• One computer can typically only handle a few links

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Data Transfer RatesTransfer rate Time to transmit a 20 page report(bits/sec) (36000 bits/page say)

300 40 mins 2,400 5 mins 9,600 1.25mins 19,600 37.5 secs1,000,000 0.072 secs

Eg BT Broadband 512000 bits/sec

a 512*512 colour image with24 bits/pixel is 6 million bits (uncompressed)

Compression algorithms are an important key

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Local Area Networks (LANs)

• Typically used in a single laboratory or building

• Typically run over copper wire or fibre optic cable

• Ethernet is popular

can now run at 1 gigabit /sec point to point

computers typically attached to coaxial cable at tap

points but can use twisted pair or fibre optic cable

or more recently wireless

• FDDI Fibre Distributed Data Interface

less popular than ethernet

interfacing is more difficult

peak rates 200 Mbits/sec

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Local Area Networks (cont)

• ATM Asynchronous Transfer Mode

technology for high data rate communications

can work at rates >> 100 MBits/sec

typically used for backbone of a WAN

(Note Ethernet and FDDI are LAN technologies not appropriate for WANs)

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Network Protocols

• Computers communicate over networks using protocols which determine the format of messages

• Protocol for the internet is TCP/IP Transmission Control Protocol/Internet Protocol

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The Internet• Loosely administered network of networks

• Agreed procedures for access and intercommunication

• Internetworking uses gateways, routers and firewalls

• Gateways: convert data traffic from one network format to another. They link LANs to WANs and WANs to WANs

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Routers• Decide which route through the network a

message should take to continue towards its destination

- networks are now very complex

- many different paths between points

- routers communicate with each other about network faults

- busy or broken routes can be avoided

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• telnet provides remote logon to distant computer• ftp transfers files between computers on the internet• ssh and sftp (secure shell) provides encryption

phl/40% telnet penelope.ecs.soton.ac.uk

Trying 152.78.68.135...

Connected to penelope.

Escape character is '^]'.

SunOS 5.6

login:

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Host Addresses

• Computers on the Internet have a unique address or host number.

• E.g. 140.138.30.5

• First six digits typically identify company or campus

• next group identifies eg a department

• last group identifies a specific computer

• Symbolic names can be associated with these

e.g. penelope.ecs.soton.ac.uk

• DNS Distributed name service keeps track of names and addresses

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Firewalls

• Used to protect local networks or individual computers by implementing access controls to and from the internet

• all traffic coming in or going out must pass through it

• only authorised traffic gets through

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Firewalls• can restrict insecure network services• restrict access to certain hosts• log activity• control use of internet• limit security effort to just one or a few

computers• do not necessarily protect against viruses in

files transferred by ftp

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Networks and Distributed Computing

• Networks of computers allow distributed access to resources

• Files may be configured so they may be seen by users of several machines

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Client Server Model

• Applications may be split between processors• Client/server model is a popular architecture• Client sends request to server for a particular

service• Server responds and may need to process

data, retrieve information or make requests to other servers etc to service the requests

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Client Server Model (cont)

• Clients and servers are software processes which are really two halves of the same application

• The world wide web uses a client server model• Browsers are clients… send request to web servers

for documents• Remote web server software receives the request

for a document, retrieves it and sends to client

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Client Server Model

• Clients and servers may be on the same or different machines

• One client may access many servers

• One server can serve many clients

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Client Server Model• Popular as makes good use of networked

resources• Growth in internet has increased popularity• Single repositories of data may be

maintained more easily eg database servers• Server typically sits on a large machine and

may be relatively expensive• Client can run on a small, low cost platform

if necessary

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Usenet and the World Wide Web

• Two different application which are usually accessed via the internet

• Both are world wide information systems but different in nature

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Usenet• Usenet is a distributed online bulletin board

(discussion group) system begun in 1979 - a set of news groups hierarchically classified by subjects

• Users can read, contribute and reply to postings on almost every conceivable subject

• Contributions are posted to the newsgroups• Newsgroups are broadcast to sites which take

them• Sites can choose which sites they take

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Usenet• Some groups are moderated• Most are open• Newsreaders are similar to email software and

allow you to select, read and respond to postings• Unlike a bulk email, only one copy of the usenet

feed is kept on a particular site• Web browsers now offer facilities for accessing

news groups without the need to receive the feed.• Information in Usenet is mainly transient

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The World Wide Web• Information is less transient than in Usenet• The web is a way of sharing access to documents

and navigating between documents using hypertext links

• The web has become an attempt to organise the bulk of the information on computers attached to the internet in an easily accessible way

• Invented by Sir Tim Berners-Lee in 1989 at CERN. He has a chair here in Southampton in the School of Electronics and Computer Science and at MIT and is giving his inaugural next month!

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The WWW

• The WWW is a client server system• Internet Explorer and Mozilla/Firefox are popular

web browsers (web clients)• Web documents are held on web servers• Web documents are usually written in HTML

(HyperText Markup Language) or increasingly XHTML (eXtensible HTML) which specifies the document content structure, (titles, paragraphs etc) and any links to other documents.

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Hypertext links and the WWW

• Hypertext systems allow non-linear reading of information using buttons and links for navigation

• Links in hypertext provide an association between some text (the source anchor) and another document (the destination of the link)

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Hypertext links and the WWW

• Each document on the Web is identified by a URL (uniform resource locator) e.g.

http://www.ecs.soton.ac.uk/dir1/file3.htm• Three parts:- transfer protocol- internet ddress of server where document is held- the pathname of the file containing the documentURLs are used in browsers to specify which documents to

readURLs are used in documents to specify destinations of links

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Some Other Aspects of the Web

• Documents on the web involve more effort than emailing to a usenet newsgroup for example. Web tends to be used for more durable information

• Search engines (Google, Yahoo, AltaVista)

• Links from non text.. image maps

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Newer Aspects (Web 2.0 ?)• Blogs or web logs - a website into which text can be added

easily (typically using web based forms) and are displayed in reverse chronological order

Blogging: - keeping a web log• Wikis -a website that allows users to easily add and edit

content and is suitable for collaborative writing • Community tagging (Flickr)• A folksonomy is an internet based information retrieval

methodology consisting of collaborativey generated, open-ended labels that categorize content such as Web pages, online photographs, and Web links.

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The Semantic Web"The Semantic Web is an extension of the

current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation." -- Tim Berners-Lee, James Hendler, Ora Lassila, The Semantic Web, Scientific American, May 2001

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The Semantic Web (cont)• provides a common framework that allows data to

be shared and reused across application, enterprise and community boundaries.

• collaborative effort led by W3C with participation from a large number of researchers and industrial partners.

• based on the Resource Description Framework (RDF), which integrates a variety of applications using XML for syntax and URIs for naming.

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The Grid• Grid computing is a form of distributed computing that

involves coordinating and sharing computing, application, data, storage, or network resources across dynamic and geographically dispersed organizations.

• Grid technologies promise to change the way organizations tackle complex computational problems. However, the vision of large scale resource sharing is not yet a reality in many areas

• Grid computing is an evolving area of computing, where standards and technology are still being developed to enable this new paradigm.

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The workshop Week 1

• Building 44 Room 1061

• Creating your own web pages