1. M150: Data, Computing and information Outline 1.Unit two. 2.What’s next. 3.Some questions. 4.Your questions. 1

2. 1- Unit two : Representation  Communication, convention and representation.  Properties of representations.  Picking representations.  Sharing and formats.  Computer based activity: a case study. 2

3. 1- Unit two : communication  Communication satisfies the following requirements:  Need for human beings to interact with each other.  A means for sharing information.  Sophistication that sets us apart from animals. 3

4. 1- Unit two : communication  Communication also governs the human/machine and machine/machine relationship:  Extending the human/human communication.  Internet connectivity.  Chatting.  Emails.  Using computers to solve problems or perform tasks either individually or collectively.  Word Processing.  Speech Synthesis.  Iris scanning.  Interferometry.  Etc… 4

5. 1- Unit two : communication  Communication between two (or more) parties requires a common ground, an agreement that all can follow and understand.  Such an agreement would be known as a convention or a protocol. 5

6. 1- Unit two : convention  The main convention for human/human communication is the language.  Some protocols for communication with computers:  HTTP (Hyper Text Transfer Protocol) for web pages addresses.  FTP (File Transfer Protocol) for downloading files from the Internet.  SMTP (Simple Mail Transfer Protocol) for sending and receiving emails. 6

7. 1- Unit two : convention  A convention is all about representation which is a combination between a form (symbol, image, sound, etc…) and a content. 7

8. 1- Unit two : Representation  Properties of representations:  The form of the representation must be perceivable in a way.  The communicating parties understand the relationship between the form and the content. 8

9. 1- Unit two : Representation  Examples of representations:  Auditory perceived as sound (ex: spoken language).  Visual perceived as sight (ex: flags, traffic signs, etc…).  Tactile perceived by touch (ex: Braille alphabet). 9

10. 1- Unit two : Picking Representation  The relationship between form and content is not predefined, it is a consensus between the communicating parties.  The following form would mean “V” in English as it would also mean 5 in Roman numbers (context sensitivity).  A key element for a representation is precision (ex: clock accuracy in the representation of time). 10

11. 1- Unit two : Picking Representation  The choice of a representation is crucial for achieving a certain task.  The fit-for-purpose criteria is essential, a representation must include sufficient information while stripping out irrelevant detail.  The process of minimizing information for a fit-for- purpose representation is called abstraction. 11

12. 1- Unit two : Representation characteristics  Very few representations are independent, most of them belong to complex representation systems which have two characteristics:  The form of a representation is made out of basic parts.  The meaning of the representation is constructed from the meanings of its basic parts. 12

13. 1- Unit two : Representation  Examples of complex representation systems are a game of cards and the traffic signs system.  For the cards:  The basic parts are the card numbers, colors, and symbols.  The meaning or value of a card in a game depends on the features mentioned here above.  For the traffic signs:  The basic parts are the shape, color, symbol (number or image).  The meaning of a sign is build out of the parts mentioned here above. 13

14. 1- Unit two : Representation  In this traffic sign example:  Sign (a) is a circle which means an order, its color is blue, and has an image of a bicycle, it is a representation of a road only allowed for bicycles.  Sign (b) is also a circle which means an order, its color is red, along with an image of a bicycle, it is a representation of a road prohibited for bicycles.  Sign (c) is a triangle which means a warning, its color is red, with an image of a bicycle, it is a representation of a warning that there may be cyclists on the road. 14

15. 1- Unit two : Representation  A system where complex representations can be built out of more basic forms, and where the relationship between form and content is predictable, is considered as a language.  Human languages abide by this definition, computer languages also. 15

16. 1- Unit two : formats  Computer languages facilitate communication with and between computers.  Formats are a type of computer languages:  They represent the detail of the input and output associated with specific applications.  They ensure consistency, a document is displayed the same way every time it is opened by a user.  They enable sharing, a document is understood by output devices such as printers. 16

17. 1- Unit two : formats  There are two types of formats:  Proprietary formats protected by copyright laws, usually associated with popular applications for a large user public (ex: Microsoft Word).  Public formats are free, they encourage the development of new applications based on such formats (ex: HTML). 17

18. 1- Unit two : formats  Formats are not prefixed, some new formats may emerge, while others follow their evolution, and others even disappear or become obsolete.  New formats appear with new hardware equipment.  New versions of formats allow updated and enhanced features.  Some formats become obsolete because old technologies disappear. 18

19. 1- Unit two : format compatibility  In order to ensure compatibility between formats:  Either standardize a particular format where a very large group of users agrees to use it.  Or allow conversion between format which means one format can always be translated into another. 19

20. 1- Unit two : standardization  Definition  Advantages of standardization:  Compatibility ensured between a lot of applications as long as the standard is respected.  New formats and standards can evolve together.  Users don’t worry about sharing and communicating.  The responsibility of ensuring compatibility can be delegated to programmers and doesn’t lie on the user.  Drawbacks:  Reduction of the number of formats.  A new format evolves slowly into a standard.  Adding new features to an existing standard is expensive and time consuming. 20

21. 1- Unit two : conversion  Definition  Advantages of conversion:  Very beneficial between two standards each respected by a large group of applications.  Ability to translate documents from an obsolete format to a current format.  Drawbacks:  Inability to map all features of a certain format with another.  Difficulty in coping with the evolution of standards and formats as the conversion programs also need to keep track of the evolution.  Many standards are currently in use, it is not realistic to develop conversion programs between all of them, gaps will always exist. 21

22. 1- Unit two : Representation  File, file name, extension  Allowed characters: some characters are not allowed in the file name depending on the application and the operating system.  A file name needs to reflect in a way the content of the file. 22

23. 1- Unit two : extensions  Some extensions: 23

24. 2- What’s next  Unit 3: Crossing the boundary: analogue universe, digital world  The world we live in.  Analogue information: digital representation.  Crossing the boundary.  Going back.  What if? … changing the digital world.  Crossing the boundary – a final word. 24

25. 3- My questions  In which ways communication is important for human beings?  Explain how the same message can be interpreted in different ways?  Is a specific behavior expected during communication?  What are the advantages and drawbacks of using email?  Does the social background influence the way a representation is interpreted? How?  What is Microsoft?  What type of formats does Microsoft deal with?  What is a freeware?  What would you do if you encounter a file of a format unknown to you?  Give an example of an obsolete application?  Give an example of a format which have evolved into a newer format? Name extensions? Name associated applications?  Do different operating systems work with different standards and formats? Elaborate? 25

26. 4- Your questions ? 26