Comp123examnotes

Comp123examnotes PowerPoint PPT Presentation


  • 259 Views
  • Uploaded on
  • Presentation posted in: Internet / Web

Wendy G Lehnert,

Download Presentation

Comp123examnotes

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Slide 1:Internet

Wendy G Lehnert, “Internet 101, A Beginners Guide to the Internet and the World Wide Web”,Addison-Wesley, 1998 The Internet is simply a network of computers, linked together all over the world. A “network of networks”. size, history http://www.isoc.org/internet-history/ brief.html

Slide 2:Ownership, no rules “membership” by connecting to an ISP Packet-switching model (origin, destination, file name, packet number) LAN or WAN Every network has a IP address (URLs) Protocol://host computer/path/filename major domain name edu,com,org,net,gov country code au uk Protocol defines the type of connection you make to the Internet. WWW-http

Slide 3:Protocols

A set of rules for communicating the end points in a telecommunication network use when they send signals back and forth regardless of computer type need internet connection, appropriate software IP-internet protocol, TCP/IP-transmission control protocol, HTTP-hypertext transfer protocol, SMTP-simple mail transfer protocol, FTP-file transfer protocol, telnet, (video protocol?) how we make connection http:// ftp:// telnet://

Slide 4:Caches and proxy servers

The cache is simply a temporary storage area where your browser stores files that it downloads. Using BACK button. In Internet Explorer: temporary internet files under windows folder Proxy server - cache provided by ISP, invisible to user, intermediary between user and Internet, filters requirements, looks at local cache, requests server on Internet on behalf of user

Slide 5:Firewalls

In computer networks used to control the material that passes between a network and the outside world. Mixture of hardware and software that acts as a buffer between your network and the rest of the Internet. The firewall controls access into and out of your network.

Slide 6:Web Pages

Web page uses hypertext markup language view-page source home page (start of the book) Frames - designated sections of a page with different source, URL: right click-properties internet address - address of network e-mail address - address of account web page address - address of file

Slide 7:Searching the Web

Search Engine is a Web page which has been set up to allow you free web searching and support service. Altavista: Advertising, find good content search engine use a spider or crawler which work its way around the Web from link to link, collecting data to create a database. Spider/crawler, a database, software query

Slide 8:Searching

Spider captures references to many web pages out of date, moved location, account expired syntax use on queries “…..”, multiple words, comput*, be specific, and/or/not, + - hitlist, directory search engines (index of categories ), key word search engines

Slide 9:Favourites

Internet Explorer- Favorites Netscape Communicator- Bookmark URL and title, housekeeping use official sites referencingbooks: title, author, publication details, page number referencing Web pages: URL, author, date found

Slide 10:Search within page:edit-find, search button evaluating search engines: database, specific, search facilities being found when creating a site: query words in title or start, close together, many instances of query words, list of search engines, requirements, let them know, include links http://www.albany.edu/library/internet/second.html

Slide 11:Word Processing (2)

Document (.doc) has content ( text, graphics, charts) and form (appearance). “This is a text file “Text.txt contains 21 characters (the 19 characters that we wrote, plus an end-of-line character and an end-of-file character), Word.doc contains 19456 characters! RTF contains 2582 characters. RTF (Rich Text Format) it is a file format that allows you to exchange document files in text format between different versions of the same word processing software, Different word processing software packages, Different operating systems.

Slide 12:Word Processing (3)

Save, Save As, Autosave .tmp file keeps new changes before saving ASCII and Unicode show/hide on toolbar for structure of layout sections, margins in page setup headers and footers, make tables, help option (contents-index).

Slide 13:Word

RAM (random access memory) and ROM( read only memory) with documents Clipboard - temporary memory space copy-paste cut-paste Deleting, Undo, Redo button Find ( can use * ? ) and Replace Insert-symbols (special characters) Clip Art and WordArt

Slide 14:Tools in Word

Spell checkers: language, technical and proper names, grammar errors of context, use of add button, Grammar Checker - Auto Correct - Thesaurus Properties of files to see statistics

Slide 15:HTML

HTML is the language that most Web browsers use. We say that most web pages are coded in HTML

Slide 16:HTML and Web Browsers

In this case, the "compiler" or document handler is your Web browser (Internet Explorer or Netscape) which is designed to handle text documents encoded with HTML tags.

Slide 17:How to start HTML

<html> <head> <title>First Marked up Document</title> </head> <body> ………… </body> </html>

Slide 18:Backgrounds

<body background="htmlbg.gif" bgcolor="#ffffcc" link=#ff7777 text=#cccccc> Declares background and default colours of background, text, and links in the web page.

Slide 19:Headings

the beginning and end tags are identical except for the forward slash (/) <H1>Make your own Heading</H1> <h2> smaller <h3> and smaller <h4> and smaller <h5> and smaller and <h6> smallest 

Slide 20:Formatting text

<font color="#FF0000"><font size=+2> ………….. </font></font> <b><u><i> comp123 </i></u></b> <hr WIDTH="100%"> draws a line <center> </center> centres text <br> and <p> line spaces

Slide 21:Images

<img SRC="Aobo.gif" height=118 width=350> Make sure picture is in same folder as web page (html file) The tag <img> has a number of attributes including "width", "height", "align“.

Slide 22:Links

<a href="http://www.opera-australia.org.au/”>link to opera page</a> <a href=“page1.html”>link to Web Page 1</a> <a href =“#Top”> go to top of page</a>

Slide 23:Lists

<li>............list item(puts a "dot" before each item) <ul>............unnumbered list <ol>............ordered list (numbers each item) <ul>…</ul> or <ol>…</ol> <li>item 1</li> <li>item 2</li>

Slide 24:Tables

<table> .... </table> define a table <th> specifies table heading <tr> specifies rows in a table <td> ... </td> define data contained in a cell <table border=4 width=100%> <th>Heading1</th><th>Head Cell 2</th><tr> <td>Cell 3</td><td>Cell 4</td><tr> <td>Cell 5</td><td>Cell 6</td> </table>

Slide 25:toolbars

Picture - controls a selected image. You can use this to adjust the brightness or contrast of an image, or carry out other functions. Office Clipboard - It used to be a fact that the clipboard could only hold one thing at a time. Using the Office Clipboard, as outlined in the text, allows you to store up to 12 different items on the Clipboard at once. Tables and Borders - This can be used as another way of controlling the tables in your document; you don't have to go to the Table menu.

Slide 26:Fonts

Scaleable Fonts:can be adjusted to any size, and can be printed well on any printer that prints graphics. Printer fonts are fonts that are built into the printer. True type or postcript fonts Screen Fonts: In order to display a font on your screen, the font type and size must be installed in your computer. Screen fonts are bitmapped fonts.

Slide 27:Lists : ordered or unordered, flat or multilevel. An ordered list would be used when whatever is being listed should be numbered while an unordered list may be used for a list of related items which could appear in any order. A normal list is flat, only one level, but it is possible to have a multilevel list (Outline Numbered List). Mammals Dogs Labrador Poodle Horses Dolphins

Slide 28:Paragraphs

“is any amount of text, graphics, objects or other items that are followed by a paragraph mark” (¶) You insert a paragraph mark each time you press “Enter” Wrap around - word wrap

Slide 29:Widow and Orphan Control

Widow: the last line of a paragraph printed by itself at the top of a page Orphan: the first line of a paragraph printed by itself at the bottom of a page Keeping lines together

Slide 30:Hyphenation

Allows more text to fit on a line Improves appearance Often used with full justification (e.g. newspaper columns) In Word can choose automatic or manual

Slide 31:Headers and Footers

Puts vital information on each page Can be text, drawing, page number, date, file name etc Need to use sections to have different headers and footers (as in assignment) Worth getting to know Logos First page

Slide 32:Templates

Master copy for all documents of a certain type Can include text and graphics Sets margins and document formats

Slide 33:Normal.dot

Times New Roman 12 pt (in Word 2000) Left aligned Single spacing ….

Slide 34:Customised Templates

Saved as .dot files Easiest way to make a template: Open a document that has the formatting you want, and save it as a template Task for you

Slide 35:Hidden text

Hides notes and comments in a document Options Can be seen on screen (or not) Can be printed (or not) Warning - be careful how you use it!

Slide 36:Mail Merge

Mail Merge can be used to merge any kind of data with any other kind of document to individualise the documents. create a mail merge, need the data document and the merge document. The data document needs to be a tab-delimited or comma-delimited text file, which is simply a file with repeating fields that are separated ("delimited") by a tab character or a comma. Set up in MS Word, MS Access, MS Excel, or Outlook.

Slide 37:Bits (smallest unit of information) 1 bit = 0 or 1 Byte (8 bits) 1 byte: A single character Kilobyte (approximately 1000 bytes) 1 Kilobyte: A very short story 2 Kilobytes: A Typewritten page Megabyte (approximately 1 000 000 bytes) 1 Megabyte: A small novel 5 Megabytes: The complete works of Shakespeare 100 Megabytes: 1 metre of shelved books 650 Megabytes: A CD-ROM

Data representation

Slide 38:Gigabyte (approximately 1 000 000 000 bytes) 1 Gigabyte: A pickup truck (eg. Ford F250) with cargo area filled with printed paper to a depth of 40 cm. 20 Gigabytes: A good collection of the works of Beethoven 100 Gigabytes: A floor of academic journals Terabyte (approximately 1 000 000 000 000 bytes) 1 Terabyte: 50, 000 trees made into paper and printed 10 Terabytes: The printed collection of the US Library of Congress Petabyte (approximately 1 000 000 000 000 000 bytes) 2 Petabytes: All US academic research libraries 200 Petabytes: All printed material Exabyte (approximately 1 000 000 000 000 000 000 bytes) 5 Exabytes: All words ever spoken by human beings. How many bits / bytes in a floppy disk / CD-ROM / in 10 GB? Conversion of binary to decimal

Data representation

Slide 39:Representation standards

ASC II and Unicode Conversion of characters, numbers and symbols to binary numbers A = 100000001 B = 10000010 (1 byte) ASC II limited to 256 (28) different variations or characters A = 1000000000000001 (2 bytes) Unicode limit is 65000 different variations

Slide 40:Memory, CPU

RAM - random access memory volatile, temporary, fast access ROM - read only memory non-volatile, permanent, slow access, CACHE The processor is called the CPU central processing unit compatibility, speed, RISC (reduced instruction set computer) - IBM for Macs faster CISC (complex instruction set computer) - Intel for Pentiums slower Fetch instruction - Memory - Bus interface unit - pre fetch unit-decode unit- control unit- ALU arithmetic logic unit (registers of 32 and 64 bits)-sent back to memory Machine cycle: instruction set is read - write - move –operate on data- make decisions Algorithm that repeats forever: fetch instruction – increment program counter – decode instruction – obey instruction

Slide 41:Hardware

Buses (travel between components of the computer in 8, 16, 32 bits) Ports (serial and parallel) Peripherals - input, output, storage (hard disk, floppy disk, tapes, zip, CD ROM, DVD) Moving data around - buses, ports, expansion slots, scsi drives Buying a computer - what will you do with it? Cost – software- expansion

Slide 42:Software

Software: compilers software applications, system software Compilers and translators - translate programs to machine language Programming languages - C++ Java Basic How CPU executes a program (adding 2numbers): get (read) number at memory location x and place in register A, get another number, add contents of registers and put in register C, write (copy) register C to memory location y.

Slide 43:Programs

Integrated software: cheaper, transfer of data easier, feels and looks same Public domain software, shareware, freeware Proprietary software–licence(allowed to use the program,still property of the company) piracy

Slide 44:System Software

Taking care of hardware issues relating to what you are doing in software Operating systems: keeps hardware running efficiently, makes process of commun9icating with the hardware easier communicate with peripherals, coordinates concurrent processing of jobs (multitasking), manages the memory, data and program management, monitors resources, accounting and security, coordinates network communications. Multitasking is when the computer seems to be working on several programs at the same time (speed). Utility software: tools for doing system maintenance and some repairs the OS can’t automatically handle. Virus scan, fix corrupted data files

Slide 45:Operating System

MS-DOS, Macintosh, Microsoft Windows User Interface- software (application) program - operating system (hardware) Software compatibility (RTF) and reliability OS lives in ROM and starts up computer with “booting” process. Character based and Graphical User Interfaces (GUIs) – (advantages of GUIs) intuitive, consistent, forgiving, protective, flexible.

Slide 46:Bandwidth

bandwidth - amount of information cable can hold (allow to travel on it) ISDN -integrated services digital network - callup digital line with 128Kbps T1 and T3 direct digital with 1.5-3Mbps Intranet – a small copy of internet at work inside the LAN/WAN network of a company. Extranet – a private network between company and business clients

Slide 47:Linking Up: Network Basics

Why is networking important? Cost allows people to share hardware Efficiency & Productivity allows people to share data and software Opportunity allows people to work together in ways that are otherwise difficult or impossible

Slide 48:LAN (Local Area Network)

Network of interconnected workstations Sharing common resources Within a relatively small geographic area

Slide 49:Client-Server LAN

Server Storehouse for software and data Management of shared resources Printers Client Computers that request server services

Slide 50:Peer-to-Peer LAN

There are no servers Shared resources managed by all computers Effective for small LANs

Slide 51:LAN Architecture

Almost all LANs are set up as one of Star Ring Bus

Slide 52:Bus

Every node is connected to the bus All communication travels along the bus Only one node can send information along the bus at a time Ethernet uses this model Node Node Node Node Node Bus

Slide 53:MAN, WAN

Networks that extend over a long distance MAN: Metropolitan Area Network WAN: Wide Area Network Usually composed of smaller MAN / LANs

Slide 54:WAN (Wide Area Network)

WANs are often made up of LANs

Slide 55:Differences between LANS and WANs

LANs small geographic area WANs large LANs almost always controlled by single organisation WANs usually aren’t LANs have a regular structure WANs don’t

Slide 56:The Network Interface

A Network Interface Card (NIC): Is needed to connect directly to a network Adds an additional port to the computer Controls the flow of data between the computer’s RAM and the network cable Converts the computer’s digital signals into the type required for the particular network

Slide 57:Modem

Modulator/demodulator Connects a computer to a telephone line Connection speed: Kbps

Slide 58:A modem is needed to connect a computer to a phone line

Communication á la Modem The computer communicates with digital signals The telephone system was designed to transmit voice signals, which are analog

The word modem comes from the terms modulation and demodulation

Slide 59:How a Modem Works

Modulation Demodulation

Slide 60:A modem: Converts the digital stream of information from a computer to an analog stream in order to send a message on the telephone network

Communication á la Modem

Slide 61:A modem: Converts the analog stream of information received over the telephone network into the digital form that the computer understands

Communication á la Modem

Slide 62:Building Bandwidth

The quality of information transmitted through a communication medium depends upon bandwidth. Increased bandwidth means faster transmission speed Bandwidth is affected by the amount of network traffic, software protocols, and type of network connection

Slide 63:Intranet

An intranet is a private network that is contained within an enterprise Uses same technology as the Internet Typically connected to the internet by a firewall for security

Slide 64:Extranet

Private Internet-like network designed for outside use (E-Commerce) An extranet can be viewed as part of a company's intranet that is extended to users outside the company

Slide 65:What is an algorithm?

Problem instance is an assignment of values to parameters Algorithm for a problem is a general step-by-step method taking any problem instance and giving a correct answer for the instance Algorithm is correct (for a problem) if it gives the correct answer for every instance of the given problem

Slide 66:Characteristics of Algorithms

Algorithm: sequence of steps to accomplish a task must produce output in all cases must terminate in all cases must produce correct results in all cases must be effective(each step is doable) must be definite (specific course of action for every eventuality)

Slide 67:Algorithms vs. Programs

Aren’t they the same thing? Computer can only perform tasks specified by simple operations it can execute We need to describe how the task can be completed; which operations to perform This description is known as an algorithm A program is an algorithm that can be directly executed by a computer

Slide 68:Selecting the Appropriate Chart

Bar and column charts emphasize variations between items over time use when data falls into a few categories Line chart show trends in data over time show relationship of one variable to another Pie chart show proportion of parts to a whole XY (scatter) chart used more often to discover relationships between data different chart types are better for displaying different sorts of data bar/col: E.g. Slide 24… show emphasize variations show few categories (don’t want lots of bars or lots of groups of bars - becomes hard to read) NOTE: stacked: shows how proportions of a whole change over time line charts: graphs of mathematical functions/statistical distributions different chart types are better for displaying different sorts of data bar/col: E.g. Slide 24… show emphasize variations show few categories (don’t want lots of bars or lots of groups of bars - becomes hard to read) NOTE: stacked: shows how proportions of a whole change over time line charts: graphs of mathematical functions/statistical distributions

Slide 69:Record Macro

to automate often repeated tasks Tools/Macro/Record New Macro Macro name box - name for macro Shortcut key Description box - what macro does Record Macro Click stop record button

Slide 70:Record Macro : Example

DEMO: Click on a cell, then Tools ? Macro ? Record Macro, Then select Format ? Cells ? Pattern ? Colour and select Red; hit OK. Then stop recording. Now this macros can be applied to other cells to highlight them.DEMO: Click on a cell, then Tools ? Macro ? Record Macro, Then select Format ? Cells ? Pattern ? Colour and select Red; hit OK. Then stop recording. Now this macros can be applied to other cells to highlight them.

Slide 71:Sort or filter macros

Highlight spreadsheet Data? sort: Data? filter? autofilter ? custom

Slide 72:Run a macro

Tools/macro/select name - as previous e.g. Shortcut key combination Assign macro to button/graphic & click

Slide 73:Adding Buttons

Forms toolbar/Button Tool Active cell - location of button Drag to desired size & shape Assign macro dialog displayed To display forms toolbar: right click on any toolbar - select forms can type any text in a button - can format font/alignment/orientation of button text - can assign existing macro or record a new macroTo display forms toolbar: right click on any toolbar - select forms can type any text in a button - can format font/alignment/orientation of button text - can assign existing macro or record a new macro

Slide 74:Representation in spreadsheets

Data consists of numbers or text Numeric data is real: dates, currency, percentages are stored as real numbers We said cell: data/formula - data: assumes data numeric unless it obviously is NOT (contains letters) - e.g. next slide... So 1 stored as 1.0 in Excel - this is significant!!! Real nos aren’t exact - more presently. What you see is NOT what Excel stores - The real nos are formatted to display currency, percentage & date A20 : typed in the no. 89993 - data: number (note right-justified) A21: typed in text data - data: text A22: typed in text 123this is text (first alpha. Char. -> text) - text left-justfified A23: typed in a no. preceded by ‘ --> treat this number as text. (Note: formula bar ) Why? some numeric-looking data isn’t - never to be used in a calculation e.g. student numbers ask yourself, will it ever be used in a calculation? If not, text - cannot then be inadvertently/mistakenly used in a formula (calculation) Dates: the 2 dates have the same real no. stored which represents 1/1/00 - different formatting -> different display characteristics Currency: similarly We said cell: data/formula - data: assumes data numeric unless it obviously is NOT (contains letters) - e.g. next slide... So 1 stored as 1.0 in Excel - this is significant!!! Real nos aren’t exact - more presently. What you see is NOT what Excel stores - The real nos are formatted to display currency, percentage & date A20 : typed in the no. 89993 - data: number (note right-justified) A21: typed in text data - data: text A22: typed in text 123this is text (first alpha. Char. -> text) - text left-justfified A23: typed in a no. preceded by ‘ --> treat this number as text. (Note: formula bar ) Why? some numeric-looking data isn’t - never to be used in a calculation e.g. student numbers ask yourself, will it ever be used in a calculation? If not, text - cannot then be inadvertently/mistakenly used in a formula (calculation) Dates: the 2 dates have the same real no. stored which represents 1/1/00 - different formatting -> different display characteristics Currency: similarly

Slide 75:Query

Queries are used either to ask questions about the data in a database, or to specify those parts of a database for which data is to be changed in some way Choose the fields in a table that you wish to display Select on a certain set of the records in a table Show the selected material in some particular sequence Derive the data that is to be shown from a number of tables in the database Calculate totals

Slide 76:Queries

Access provides 2 ways to specify queries: QBE approach (Query By Example) - a graphical interface that allows you to design your query in a fairly intuitive manner. SQL (Structured Query Language) If you choose to use QBE to develop your query, you can have a look at the SQL view and see what SQL the query you design produces.

Slide 77:Three views for a query: Design view This lets you see the rules by which the query is constructed. It will show the table(s) used, the fields that have been selected, and any constraints  (criteria) used to select particular records from the table(s). Datasheet view The datasheet view shows you the information that is produced when the query is run. SQL view This view shows the SQL query that is generated from the graphical specification

Slide 78:Types of queries

Select queries: The purpose of a select query is to extract and present information from the database. The way in which we specify what is to be selected and presented is by establishing criteria. Action queries: Action queries are used either to make new tables in a database, or to alter in some way the data (make table, delete,update,append).

Slide 79:QBE

Query by example, we select the fields that we wish to incorporate in the query by: First selecting the table(s) that we need to provide the required output Then selecting (in the order (left to right) that you wish the data to be presented) the fields you need.

Slide 80:QBE

Criteria are restrictions you place on a query to identify the specific records you wish to work with. Criteria: 2124 Use Null, And Or Not, Between Null is defined as nothing - an empty or zero length string. Is Not Null (has a value in the field) <> 0 (not equal to 0)

Slide 81:And / Or

And in QBE (>= 15 And <= 18) Field: WinbCommbWordbSsheetb Criteria:"O“ "E“ "E“ "E“ Or Tu2p Or Tu3p Criteria:     Tu2p Or: Tu3p

Slide 82:Wild Cards

* (anything after or before *) Tu* (anything that starts with Tu). *p (anything that ends with p). ? - Matches any single alphabetic character (categori?e) [] - Matches any single character within the brackets (c[au]t) ! - matches any character that is not specified in the square brackets b[!ae]ll finds bill and bull but not ball or bell - #

Slide 83:Wild Cards

- - Matches a range of characters. The range is in ascending order (A - Z). a[a-d]x will match aax, abx, acx, adx # - Matches a single numeric character 1#3 would match 103, 113, 123, 133, but not 1A3.

Slide 84:Sorting

Sorting on one field Three options are available for the sequence in which any field appears: Ascending sequence Descending sequence Not sorted The field that you choose to sort over may be text, numeric or date

Slide 85:Show field option

The Show line on the QBE grid contains a Tick box for every field that is used in the query. When the box is crossed, the field is shown; if it is not, it is not visible when the query is viewed in datasheet view.

Slide 86:Saving queries

All query names start with Qry Update queries start with Qry Update  Append queries start with Qry Append Name queries when you close the datasheet view of query

Slide 87:Multi-table queries

Much of the power of querying tables in a relational database is the ability to bring together data from multiple tables.

Slide 88:Basics

Graphics are represented by pixels (640x480, 800x600, 1024x768, 1280x960 screen sizes) Quality of graphics is determined by: Resolution of the screen (dpi) Number of colors Determined by hardware and software

Slide 89:Forms of Graphics

Bit mapped (raster graphics) Objects (vector graphics)

Slide 90:Black and White

Grey scale Represented as 1 byte per pixel 256 shades – more than naked eye can distinguish See demo at: http://www.aa6g.org/Astronomy /Articles/grayscale.html

Slide 91:Grayscale

Slide 92:Colour implementation

1 byte gives 256 colours 2 bytes gives 65536 colours Tradeoff between resolution and storage requirement

Slide 93:Dithering

Dithering is the attempt by a computer program to approximate a colour from a mixture of other colours when the required colour is not available. For example, dithering occurs when a colour is specified for a Web page that a browser on a particular operating system can't support.

Slide 94:Browser Safe Palette

216-Color Browser-Safe Palette When specifying colors for Web page backgrounds, fonts, and other elements for 256-color displays (the most common display capability), you will probably want to choose from the 216 colors that look the same on both PC and Mac operating system

Slide 95:Compression

Graphics files are large The COMP123 logo is 472 x 81 pixels (38232 bytes) It is compressed to 23019 bytes Compression is the reduction in size of data in order to save space or transmission time.

Slide 96:Forms of compression

Lossless – e.g Winzip Lossy – e.g. jpeg

Slide 97:JPEG

A JPEG (pronounced JAY-peg) is a graphic image created by choosing from a range of compression qualities (actually, from one of a suite of compression algorithm). When you create a JPEG or convert an image from another format to a JPEG, you are asked to specify the quality of image you want.

Slide 98:GIF

On the Web and elsewhere on the Internet, the GIF has become a de facto standard form of image. The LZW compression algorithm used in the GIF format is owned by Unisys replaced by PNG (which is free) GIF uses up more space.

Slide 99:Sound

Measured by sampling Uses lots of space Quality is a function of Sampling rate (Telephone line is 33KHz; ) Bit rate (Twice the bandwidth (Nyquist theory))

Slide 100:Video

Combines pictures and sound Uses huge amounts of storage

Slide 101:Hypermedia

Combination of text, numbers, graphics, sound, music, video, virtual reality and other media in hyperlinked documents

Slide 102:Bandwidth

Bandwidth is directly proportional to the amount of data transmitted or received per unit time (measure of the range of frequencies the signal occupies)

Slide 103:Summary queries

Do not change the data in the database Produce total information View ?totals Created by using the ? tab Can combine the options

Slide 104:Action queries

An action query is a query that makes changes to many records in just one operation. Query?action queries There are four types of action queries: delete update append make-table

Slide 105:Delete query

Delete query Deletes a group of records from one or more tables.

Slide 106:Update queries

Example: Update the results for the Winb Basic assignment First – be quite clear about the rules.

Slide 107:Append query

Adds a group of records from one or more tables to the end of one or more tables Example: Add new students to Studdetails

Slide 108:Make Table

Creates a new table from all or part of the data in one or more tables Used for: Creating a history table that contains old records Creating a table to export to other Microsoft Access databases Taking a snapshot of a table

Slide 109:The expression we use:

Value:[UnitPrice] * [Quantity] What do the square brackets mean? Existing fields New price: [price]*1.1

Slide 110:SQL – Structured Query Language

Each query that you create produces an SQL version You can check this – there are three views of a query: Datasheet Design SQL

Slide 111:What is Electronic Commerce?

Electronic Commerce is the term used when commercial transactions take place across the Internet or another private network without human intervention

Slide 112:Business to Business Transactions

Most common form of E-Commerce Used in: Manufacturing Sales Allows for Just-In-Time manufacturing

Slide 113:EDI (Electronic Data Interchange)

EDI refers to the exchange of electronic business documents (no human intervention) EDI standards Agreement between 2 organisations

Slide 114:B2C Business to Customer

Growing area Some successes, lots of failures Must be built into the business model

Slide 115:Internet banking

Faster Cheaper More flexible Not time dependent

Slide 116:Web based retailing

Business to Customer The issues Is it working? Amazon has never made a profit for a whole year What sort of products sell?

Slide 117:Advertising, Marketing

The 4 Ps of Internet marketing Product Price Place (Distribution) Promotion

Slide 118:Security Issues

1.       Confidentiality Privacy of message (encryption) 2.     Integrity Detecting message tampering(Hashing) 3.     Non-repudiation Provision of irrefutable evidence of origin, receipt and contents (Digital signatures etc)

Slide 119:Cont ..

4.     Authentication Is the sender who he/she claims to be? (Digital signature, password etc) 5.     Authorization Access control (limiting entry to authorized users) (Firewalls, passwords etc)

Slide 120:What is Cryptography?

Cryptography is a means of mathematical encoding that converts messages into a form that is unreadable, in an effort to maintain confidentiality of data.

Slide 121:Public key cryptography

There are two keys, public key, private key Public keys are published Private keys are kept secret (you keep your own private key)

Slide 122:Sending a message:A to B

Adam encrypts the message using Beth’s public key Beth decrypts the message using her private key

Slide 123:

Anyone can send you a message Only you can decode it How does the recipient know who really sent the message?

Slide 124:What is a system?

A system is much more than the software that is used. System incorporates the software the training of users installation plan user documentation maintenance plan …….

Slide 125:Software Development Life Cycle

Requirements analysis Design Implementation Testing Installation Maintenance

Slide 126:Systems Development Life Cycle (1)

First catch your problem (the hardest bit it to get this right) Understand how the problem fits into the organisation’s overall scheme of things

Slide 127:Systems DLC (2)

Design a solution that fits into the organisation Develop the system as a whole Software Testing Training Systems documentation User documentation Installation plan Maintenance plan Plan for obsolescence

Slide 128:Systems DLC (3)

Systems Installation Systems maintenance (about 60-70% of the cost of a system is spent after the syetem is installed)

Slide 129:What is a VIRUS?

A virus is code inserted into a program cause some unexpected/undesirable result replicates itself

Slide 130:What should I do?

Install Anti-virus Software Use a legal copy - why? E-mail Downloads Floppies

Slide 131:How does Anti-Virus Software Work?

Signatures built in to the infected file The anti-virus trail Collect suspicious files Identify similar cases Work out what the virus does Develop antivenene Add to repertoire

Slide 132:Boot Sector Virus

Boot sector floppy disk hard disk Effect?

Slide 133:File Infector Virus

Attaches itself to program files .COM .EXE The effect?

Slide 134:Macro Virus

Typically Word or Excel Effect - often inserts rubbish Note the warning in Outlook!

Slide 135:Trojan Horse

Program that is expected to do one thing and does another Password capture

Slide 136:Worms

Self-contained program Spreads functional copies of itself Does not attach to a host program Two types Host worm Internet worm

Slide 137:What is Artificial Intelligence?

AI is the study of ideas which enable computers to do the things that make people seem intelligent (Winston). AI is the study of how to make computers do things which at the moment people are better at (Rich) AI is the study of the computations that make it possible to reason, perceive, and act (Winston).

Slide 138:How do you tell if a computer is intelligent?

Turing test (1950) A machine can be deemed intelligent when it can pass for a human being in a blind test. (computer, human) answer questions from human….depending on answers human must determine which answer came from a machine…if fooled then computer deemed intelligent. No computer has passed test.

Slide 139:Natural Language Processing

Speech recognition Language understanding Translation Language generation Text to speech synthesis Problem Syntax Semantics Syntactical ambiguity Semantic ambiguity Fluidity of language

Slide 140:Expert Systems

A software program designed to replicate the decision making process of a human expert. Examples Bank loans Credit card applications Medicine - diagnosis systems Design - Xerox paper handling systems Farming - CSIRO

  • Login