Resume
Exam summary BIS
- Établissement
- Vrije Universiteit Brussel (VUB)
this is my summary for BIS from all the slides of the lectures and some additional notes
[Montrer plus]
Aperçu du contenu
1. Goal of this courseI. What is the main purpose of this course?
To provide the studens some important concepts and tools of business information
technology for good communication between management and computer scientists
o A few facts:
Infromation technology has become very important nowadays, but many projects
fail because of:
▫ Shortages or even absence of agreements
▫ Wrong explanation or misrepresentation
▫ …
Why is the knowledge of IT important for a company, organization and its
management team?
▫ Good communication
▫ Efficiency
▫ …
52% of the investments are related to IT
Return on IT versus IT envestment paradox: high investments in IT do not always
mean a higher productivity
80-90% of IT projects fail
o Alginment definition
"applying IT in an appropriate and timely way and in harmony with business strategies,
goals and needs"
o Weakness – risk:
Smooth progress depends on the appropriate functioning of IT
o What if the IT is down?
Problems with:
Web-shop
Management of orders
Payments
Customer service
…
II. Some introductory concepts
IT is increasingly present in our modern society
Input -> computer -> output
o Hardware:
Input
Output
Computer
▫ Memory: RAM/ROM
▫ CPU (Central Processing Unit)
o Software
Sequence of orders formulated by programs
Conversion into machine language
Machine language: the set of symbolic intstruction codes usually in binary form
that is used to represent operations and data in a machine
Modules
▫ Reuse
▫ Less complex
▫ Splitting into sub-problems
▫ Error module easier to find
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, ▫ Collaboration with several people
Besides programs, software can also be DATA
o Database
Organized collection of data stored in a computer
Relational database
o Network
Multiple comuters communicate and exchange data
Types: PAN, LAN, MAN, WAN
Protocols:
▫ TCP: Transmission COntrol Protocol
▫ IP: Internet Protocol
o Servers
Computer only for calculation and storage
o Internet
Teh biggest internetwork
In OECD penetration rate of +/- 83%
o Computer architecture
Fundamental organization of the computer system
▫ Phase 1: mainframe
▫ Phase 2: PC & client server
▫ Phase 3: browser/cloud
o Processes
A business process is a sequence of steps/actions with the aim of generating a
product or a service.
Start in '90: need for operation between various actors/departments within an
organization
o Information System
The combination of IT hardware, software, processes and people who use it
2. Algorithms
I. When solving a problem using the computer it is strongly recomended to go through the
following steps:
o Problem definition
The problem will be fully and accurately defined: from which initial situation is started,
which results must be obtained and what is the link between both.
o Solution strategy
This is the choice of a solution method and of the data repersentation:
Trying to divide the problem into smaller sub-problmes
Agreeing what will happen in each sub-problem
o Representation of the algorithm
Examples: flow chart, nassi-schneidermann-diagram, pseudo code,...
o Programming
When encoding, the fully elaborated algorithm translated into the selected
programming language.
For example: ADA, Basic, C++, Cocol, Delphi, Fortran, Java, Javascript, Pascal,
Python, R, Visual Basic,...
o Compiling
To detected eventual suntax errors
Translation into machine language
Compiler versus interpreter
o Testing
Results must also be logically correct
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, Compare with results obtained in a different way
Test all different cases
o Documenting
All information that will help third parties to understand, modify, improve or
complete the program
o Maintenance
After a while the program eventually has to be updated
Report changes in the documantation
II. What is an algorithm?
o Today, algorithms are used in many applications such as:
The functioning of computers
Cryptofraphy
Information routing
Planning and optimal use of resources
Image processing
Tekst processing
Bio-computing
…
o Definition:
An algorithm is a method to solve a problem:
A sequence of actions/commands/rules
Starting from a given initial situation
Leading to a certain goal
Within a finite time
The commands must be understood in an unambiguous way
III. Algorithm representations
o An algorithm can be presented by:
A flow chart
A flow chart is a scheme with basic figures instructions are included in the figures
and the figures are connected by lines/arrows
A nassi-schneidermann-diagram
Pseudo code
o Overvieuw algorithm representatations
Sequence
Selection
▫ If then
▫ If then else
▫ Case
Iteration
▫ While
▫ Repeat
▫ For
3. Programming
I. Python in a nutshell
a. A few facts
Programming language
Designed in the early 90's vy Fuido van Rossum
Affiliated with the Center for Mathematics in Amsterdam
BASIC based language based on ABC
Supported by volunteers on the internet
The Python development is led by the Python SOftware Foundation
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, Python is free software
b. Characteristics
Readable code
Structure through indentation
Statements ended by the end of the line
Variables do not receive a type declaration
Duck-typing:
▫ Type of a variable and the type of an argument does not have to be defined
▫ In the case of compilation, there is no type control
▫ In case of mismatch, an error message will folloz
EAFP (Easier to Ask for Forgiveness Than Permission)
▫ A function or method is started without first checking wether it is working
properly
Execution
▫ Written in one or more tekst files with the extension .py
Interpreter:
▫ Compiles to an itermediate form, called bytecode
▫ The byte code is independent of the operating system
▫ The next step is to change the bytecode into machine language
▫ Slower than programs written in a language with a compiler
Garbage collection
▫ Python memory space is automatically reserved for new variables
▫ Released again if there are no more references to those variables
Stnadalone executables
Libraries
c. Python single predefined types:
Integer: whole numbers
Float: with numbers after the comma
String: symbol
Boolean: true/false
d. Basic instructions
Traditional programming concepts:
Operators
= assignment
Arithmetic operatiors
▫ + addition
▫ - substraction
▫ * multiplication
▫ / division
▫ //floor division
▫ % modulo
▫ ** power
Functions input & print
▫ Print: to write something
▫ Input: to enter values in a variable
II. Programming
a. Generation programming languages
First-generation programming language
▫ Machine level languages
▫ No translator to compile or assemble
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