Kategorier: Alle - evaluation - security - data - design

af Long Le 5 år siden

725

Problem Solving Methodology BBC

The content covers a range of topics related to data management, programming, and solution development methodologies. It highlights the characteristics and structures of various data types, along with the tools and techniques used for data collection and analysis.

Problem Solving Methodology BBC

Related contents

Threats to the integrity and security of data

Events-based threats
Examples

Natural Disasters

Earthquake

Flood

Fire

File corruption

Software crash

Failure of a HDD

Power-surge

foreseeable, meaning measures can be put in place to reduce their impact
Events outside a user's control that cause a loss of data integrity.
Deliberate threats
A purposeful act by someone to cause a loss of data integrity or breach security measures.

DDOS

cause the web server to performance to suffer greatly, or even crash meaning legitimate users cannot access the website or service running on the web server.

The purpose of a DDOS is to have millions of computers infected with a worm or virus (a ‘botnet’) to simultaneously activate a payload which sends data traffic to a web server in order to overload it.

Distributed Denial of Service attack

Phishing

attempts by scammers to trick you into giving out personal information

Malware

Spyware

Adware

Generates ads in pop-up windows or browser tabs

Malware with the purpose of collecting information

Browsing history (for marketing / advertising)

Email addresses (for spam purposes)

Personal details (for identify theft)

Trojans

relies on the user downloading and running what they think is a legitimate program

A virus disguised as a legitimate program.

Worms

purpose is to spread and consume large amounts of bandwidth on a network, making the network unusable.

replicates itself WITHOUT any interaction or assistance from the user (different from a virus).

Viruses

cannot run by itself

replicate itself

Malicious software

may also contain a payload - a part of some malware that damages the computer in a specific way on a certain date or trigger.

Software designed to cause harm to data integrity.

Making data inaccessible to users

Stealing data

Deleting data

Accidental threats
measures that can be put in place to reduce their impact
Mistakes made by the user.

Characteristics

Characteristics of Networks

Maintainability

Reliability

Efficiency

Level of automation

Operational costs

Processing time

Productivity

Characteristics of Information Management Strategy

Integrity of data Security Ease of retrieval Currency of files

Characteristics of solutions
Look for effectiveness and efficiency (in evaluation criteria)

Key legislation

Look at the attachment

Networks

Check the slide
Virtual Private Network (VPN)
requires login
connect to a web-server through a different network path then normal to circumvent geo-blocking or make your internet traffic harder to track.
A secure, encrypted connection over the internet using publicly available infrastructure to access an organization's resources or intranet while off-site.
Global system of connected networks (WANs & LANs)
Intranet
accessible from outside the organisation by using a VPN.
stored on servers within the organisation.
An intranet is a collection of private network resources accessible only to an organization's staff.

Wired and wireless networks

Link:

Procedures for handling files/data

Archiving
Archiving frees up space on the primary file server, which in-tern reduces the size of backups
If the files are required, they must be retrieved from the archive system
Storing these files for an indefinite period of time in another, secure system.
Removing files no longer required for immediate access from the main system.
Security
Software ( ensure protection if someone has managed to gain physical access to an information system.)

Software (security protocols)

Transport Layer Security (TLS) and Secure Sockets Layer (SSL)

Asymmetric Key system Public / Private Keys

Public / Private Key Cryptography

A banking website provides a user’s browser with the bank’s public encryption key. The user’s username and password (plaintext) is encrypted with the bank’s public key. The encrypted data (ciphertext) is sent to the banking website. The banking website decrypts the encrypted username and password with the bank’s own private key. The bank can send out the public key to all its customers for encryption. The bank MUST keep its private key safe to decrypt the encrypted data.

Creates secure (encrypted) connections over a network (HTTPS).

firewalls and system protection

System Protection

Anti-malware software

Firewalls

stops unwanted traffic from entering a network

The encrypted data is known as ciphertext.

The original data is referred to as plaintext

Encoding information so that is unreadable without the use of the encryption key or ‘cipher’

access restrictions

Stops a user from accessing resources, even if they have managed to login successfully

Blocking users from data and resources on an IS, based on their classification in the system

access logs and audit trails

Audit Trails

Track the user activity once logged in

Access logs

Can detect strange or suspicious login activity

A record of user login attempts into an IS stored on the server.

usernames and passwords

Prevents unauthorised access to the computer system.

Physical ( protect data while it is being stored - restrict unauthorised people)

equipment

Biometrics

Photograph ID

Iris recognition

Face recognition

Fingerprints

Identifying individuals based on unique physical characteristics.

Barrier techniques

Anything put in place to prevent a person from physically accessing servers or computer equipment holding data.

Guards

Doors, locks, gates, bars, fences, walls

Zoned security strategies

Different keys open different locks, creating ‘zones’ or areas that are only accessible by employees with the required key.

Locks, alarms, fences, gates

Procedures

shredding confidential documents (disposal of paper/hdd)

checking authorisation credentials

backing up

Frequency

Highly dependant on the organisation Full Backup - Weekly / Monthly Differential - Daily Incremental - Hourly / Daily

Medium

Medium considerations

Ease-of-use

Speed (Bandwidth for data transfer)

Cost

Capacity

Cloud

Optical Disc

Tape Drives

HDD / SSD

On site / Off site Off site prevents larger disasters causing data loss

Types

Incremental

can backup more frequently Harder to restore (must be in correct order)

To restore Restore full backup Restore each incremental backup, in order, from earliest to most recent.

backup after the full backup, only contains files changed for that day, or since the last backup.

Full backup is made first

Differential

Uses less space than daily full backups

To restore Restore full backup Restore latest differential backup

Each backup after the full backup, only contains files changed since the full backup

Full backup is made first (total copy of selected files or HDD)

Full

Easiest to restore something goes wrong Access the latest backup, restore files or whole HDD from there.

largest amount of storage

All data copied to backup medium

original files are NOT removed from the main system

storing the duplicates in a secure location.

Creating a copy of files on the main system

Project Management

Factors that influence the effectiveness
Relevance

Are all the parts of the project plan relevant to the project?

Accuracy

How accurate are the time allocations, milestones and the tasks required?

Readability / Clarity

easy to read?

Completeness

contain all the required tasks, milestones, dependances?

Recording progress and influences
Logs
Adjustment to tasks and timeframes
Annotations

Making notes on the project plan were changes were made.

Concepts
Critical Path

The path followed through the project for its longest duration - this will be equal to the SHORTEST time possible to complete the project.

Time allocation

length of the bar.

Dependencies

represented with arrows

a following task cannot be begin until a previous task has been completed.

Milestones

used to judge whether a project is on schedule or not.

diamond shapes

Major points of progress in a project

goals and objectives of organisations and information systems

Example of the differences
More example

Identify the organisational and system goals and objectives in this case study.

Fred’s law firm has 2 computers. He wants his firm to be more successful, so he is updating his information system. He wants his PCs to run 20% faster to help him produce more accurate communications with customers and to increase income by 10% this year. With increased income, he can spend money on extra secretarial support because he wants his firm to get a reputation for professional excellence.

 

Organisational goal: his firm to be more successful, reputation for professional excellence.

Organisational objective: increase income by 10% this year

System goal: produce more accurate communications with customers

System objective: his PCs to run 20% faster

Organisations

Measurable statements that describe what needs to be achieved in order to reach a goal.

Help to achieve the mission statement

describe something to achieve.

Mission statement

Guides the actions of the organisation

Usually describes why the organisation exists.

A short statement describing the ultimate goal of the organisation.

Varied sizes _Single person _Multi-national company
An entity that has a collective purpose
Information system
support the goals and objectives of the organisation.

Interactions and Impacts

Impact of diminished data integrity on dependant systems (ALWAYS relate your answer back to the system in question)
Impact on Organisations

Jail

Sued

Customer loss

Reputation loss

Profit loss

Impact on SYSTEMS

Increased time taken to service customer

Incorrect information stored about customer address, letter sent to wrong person

Program crashes

Errors on invoices for new books

Garbage in - Garbage out
Factors affect access of data
Organisation of files

Where files are stored is also important

Use an appropriate file structure

Filename convention (How files are named)

Using a logical file naming convention

easier and quicker to find a file

Storage Medium

Comparison

hardware device where files are physically saved.

Examples Hard disk drive Solid State Drive USB Flash Drive Optical media (CD / DVD / BD) Magnetic Tapes

File size

Measured in Bytes

Transfer speed of data in a storage medium is measured in MB per second (MBps), networks use Mbps

1 Byte (B) = 8 bits (b) - a single 0 or 1

The amount of space on a storage medium (HDD, DVD) taken up by a file.

Advantages and Disadvantages for Stakeholders Affected by IS
Disadvantages

customers deal with IS, not a person

24/7 access - work overtime

loss of 'personal touch' or face-to-face contact with the business

deskilling

loss of jobs, people being replaced by IS

users become dependent on IS for work

start-up costs ($)

conversion of data into the new IS

training costs for staff

significant investment in getting the IS running

Advantages

more effective/efficient for customers

can access own data or history in organisation

can order goods and services online --> reduced time/effort

24/7 access

Upskilling

users of IS must learn new IT skills to use IS

increased efficiency in running the business

less employees needed --> reduced cost

automated systems --> reduced time/effort

stakeholders

For businesses, these include: employees, employers, shareholders, customers

person or group with an interest or concern in something, especially a business

Data Management Practices that Cause Conflict
user permissions

could allow export but prevent import

incompatibility

different software

different setups can cause miscommunication

manual data entry

can be valid and reasonable but incorrect due to human error

converting data from different databases

missing data

differences in data types

differences in field names

Data Mining

conflicts:

reasonableness/relevance

some information found don't make sense or are irrelevant

is there consent for data sharing?

is there consent for data mining?

done by dedicated data mining software

the analysis of large sets of data in attempts to extract patterns and knowledge

Factors Affecting Integrity of Data
Factors:

correctness

whether or not data is right or wrong (always yes or no)

authenticity

primary data most trustworthy, if not find reputable sources

how trustworthy and proven the data's source is

reasonableness

should fall within a range that makes sense

how much the data makes sense with the source material (is it related to the context?)

timeliness

1999 data vs 2019 data for current trends

data too old will be irrelevant and not provide an accurate representation of source material

how much the data is within its "use-by-date" and can provide meaningful information

length of time for 'timely' data depends on the data

accuracy

In 2017: there were 24.5 million people living in Australia (less accurate) vs. there were 24,530,282 people living in Australia (more accurate)

greater accuracy leads to more precision

how much the data is a true representation of the source material (how well data is measured)

Integrity

internal consistency or lack of corruption in electronic data

raw facts and figures that have not been turned into information

Information Systems
Output

e.g. visual(monitor), sound(speaker), paper(fax or printer) and touch(gamepad)

data that has been stored or processed by the IS and turned to information

Input

e.g. keyboard, touch screen, microphone, etc.

data that is entered into the IS

should support goals and objectives of organisation's IS (Not related to organisation as a whole)

(see pg. 3 to 4 for more info)

Goals

e.g. Reduce user errors by 50% OR Remain stable and reliable 99.5% of time

statements that describe something the organisation is aiming to achieve

Objectives

e.g Record all students' attendance and report progress OR Produce annual reports for sales

measurable statements that describe what needs to be achieved to reach a goal

allows for:

reduction in time taken to process data

improved services for customers or clients

sharing of hardware between users

sharing of data between users

combination of _________ to create, control and communicate ideas and digital solutions

Data

includes information (attendance, personal details, etc.) and work (assignments, documents, etc.)

documents/files/statistics created and modified using the IS

Processes

includes general actions (saving files, etc.) and restrictions (access permissions, etc.)

rules to ensure the IS is used properly

Software

includes OS and other websites as well

applications and services used on hardware

Hardware

includes machines and computers used

physical components of IS

People

everyone

the human beings that use the IS

Problem Solving Methodology BBC

Check out slides (have not added all info) - do not delete this list

  1. U4O2 KK09 - Technical underpinnings of Intranets, Internet and VPN

-----------------------------------------------------

Completed KK

  1. U3O1 KK01 - Characteristics of Data Types
  2. U3O1 KK02 - Data Strucutes
  3. U3O1 KK03 - Design Tools
  4. U3O1 KK04 - Input / Output and XML
  5. U3O1 KK06 - Processing features of programming languages
  6. U3O1 KK07 - Searching - Linear and Binary
  7. U3O1 KK08 - Trace tables and test data
  8. U3O1 KK9 - Internal Documentaiton
  9. U3O2 KK01 - Techniques for collecting data
  10. U3O1 KK04 - Methods for determining solution requirements, constraints, and scope
  11. U3O2 KK03 - Analysis - Solution Constraints
  12. U3O2 KK04 - Analysis - Scope of Solution
  13. U3O2 KK05 - SRS
  14. U3O2 KK07 - Evaluation Criteria - Efficiency and Effectiveness of solutions
  15. U3O2 KK08 - Analysis Tools - Use Case Diagrams
  16. U3O2 KK09 - Analysis Tools - Context Diagrams and Data Flow Diagrams
  17. U3O2 KK10 - Design Tools
  18. U3O2 KK11 - Factors influencing design
  19. U3O2 KK14 - Project Management
  20. U3O2 KK15 - Security - Data protection and authentication
  21. U3O2 KK16 - Styles of modern applicaiton architecture
  22. U3O2 KK17 - Types of goals and objectives
  23. U3O2 KK18 - Legal Requirements relating to ownership and privacy of data
  24. U4O1 KK01 - File size, storage medium and organisation of files affect access of data
  25. U4O1 KK02 - Data Structures - Associative Arrays
  26. U4O1 KK03 - Security, archiving, backing up and disposing files
  27. U4O1 KK04 - Processing features of a programming langauge
  28. U4O1 KK05 - Sorting Algorithms - Selection and Quick
  29. U4O1 KK06 - Characteristics of Efficient and Effective solutions
  30. U4O1 KK07 - Test Data
  31. U4O1 KK08 - Validation - Existence, Type, Range
  32. U4O1 KK09 - Usability testing and documenting test results
  33. U4O1 KK10+11 - Project plans - Recording progress and influences
  34. U4O1 KK12 - Evaluation of solutions and project plans
  35. U4O2 KK01 - Reasons why individuals and organisations use information systems
  36. U4O2 KK02 - Types of goals and objectives
  37. U4O2 KK03 - Types of interactions (input and output) generated by IS
  38. U4O2 KK04 - Characteristics of data that has integrity
  39. U4O2 KK05 - Key legislation that affects how organisations control the storage, communication and disposal of their data and information
  40. U4O2 KK06 - Data management practices that cause conflict between information systems, including data mining
  41. U4O2 KK07 - Advantages and Disadvantages for stakeholders affected by the operation of information systems
  42. U4O2 KK08 - Impact of diminished data integrity on dependant systems
  43. (too much)grdggdrgdgdthdhfthfthfthfhfhfh kk9
  44. U4O2 KK10 - Wired and Wireless Networks
  45. U4O2 KK11 - Threats to the intergrity and security of data
  46. U4O2 KK12 - Physical and software controls to secure data
  47. U4O2 KK13 - Hardware, Software, and Technical Protocols used to secure data

3) Development

Documentation
Characteristics of internal documentation

Meaningful names

All controls, variables and arrays in a program should have meaningful names. This makes it easier to identify their purpose just by reading the name. Use naming conventions: => v, before all variables - vName, vAge => CamelCase for controls _Description of purpose _Type of Control _FirstNameLabel, CalcButton

Comments

Purpose Reminds a programmer what a piece of code was for (its purpose) Helps team members understand each other's coding Comments are not executed and have no affect on the performance of an application.

Testing
Types of testing

Trace table

remember to list all the variables given Store values as they change Only enter a new value if a change occurs.

Algorithm testing

Example (Question 1 Section B 2018 exam)

testing table

Testing for logic errors (test the program overall)

Example

Useability (Acceptance) Testing (given to client/user)

Completed by a section of its daily users Makes sure that solution included all the required functionality Gives the chance for users to provide feedback before the solution is deployed Test functional and non-functional requirements from analysis stage. Once passed the solution is almost ready to be deployed.

Note: Testing is NOT the same as Evaluation Testing = does the solution work -->ensure validation is working Completed BEFORE the solution has been deployed Conducted by the developer User Acceptance Test - conducted by the main users of the program to make sure it does what is required.
Test data: It is extremely important that you choose an appropriate range of test data for each test. Good test data tests every possible input: Typical(Values you expect a user to enter) Edge cases (aka Inside range values - Values at the extreme ends of the allowable range) Outside allowable range (Values outside the allowed data range) Garbage input (Invalid data - wrong data type, blank etc.) Make sure you testing is through but not repetitive - the exam will often ask you to select the best set of test data, don’t select the set that tests the same type of input multiple times! Focus on testing edge cases.
What should you test?

Effectiveness

Networks - reliability and maintainability

Information Management Strategy - integrity of data, security, ease of retrieval and currency of files

Solution - completeness, readability, attractiveness, clarity, accuracy, accessibility, timeliness, communication of message, relevance and useability

Efficiency - cost, time, effort

Network - productivity, processing time, operational costs and level of automation

Solution - speed of processing, its functionality(?) and the cost of file manipulation

Non-functionality - useability, reliability, portability, robustness, maintainability.

Functionality - Does the solution do what is is supposed to?

Does the solution run?

Validation techniques

Range (data in an acceptable range?)

Type (correct data type?)

Existence (Does any data exist?)

Validation: ensure users are only allowed to input REASONABLE data. It DOES NOT check the ACCURACY of input data. Proper validation ensures that: Your program does not crash if the user enters unreasonable or unexpected data. Users are given a prompt if unreasonable data has been entered. Users are able to re-input data.
Manipulation (Coding)
Searching algorithms

Binary searching

Algorithm: Binary searches can only be applied to sorted data. A Binary search divides a list of values in half and makes a comparison on whether the value searched for is above or below the divided value. Find the value mid-way through the data and ask: Is this the value we are searching for? If so, search is finished. If not, is the value less than or greater than the mid-way value? Search the half that should contain the data, ignore the other half. Repeat until the value is found, or is proved to be not present. ______________________________________________ Very fast to run More complex algorithm to write.. Great for large data sets, bad for small ones (use linear instead) -------------------------------------------------------------- A binary search algorithm requires the following: The array of values Low - lowest index of list being searched (0) High - highest index of list being searched (array.Length - 1) Mid - middle index of list being searched (0) Found - indicates if the value was found (false) SearchValue - value being searched for A loop to run through the search -If statements

Linear searching

Algorithm: Similar to a human looking through a list of values. Look at the first index in an array and check if it contains the data we are looking for. If not, move to the next index. Repeat this until the item is found, or you have reached the end of the array. A Linear search is the only way to search unsorted data. easy to code slow (on average it will have check half the data set to find if the value is in an array) efficient for small data sizes

Sorting algorithms

Quick sort

Uses Recursion - A function or procedure that calls itself. Divide and Conquer algorithm - data broken down into smaller pieces to be worked on. Sort Time - Faster and more efficient than selection sort. Algorithmic Complexity - More complex to write then a selection sort. Time taken to run the sort changes depending on the “unsortedness” of the data No. of Comparisons (N the number of items in the array) Best Case - N * log(N) Worst Case (rare) - N2

Algorithm: Pick an element from the array to act as the pivot value. There are many ways to pick the pivot value, but it is often best to select it randomly. Re-order all the values that are smaller than the pivot value to come before it, all the ones higher to go after it. The pivot will now be in its proper position Recursively (run the method again) apply the above steps to the sub-array of elements with smaller values and separately to the sub-array of elements with greater values. Keep applying the algorithm until the array is sorted.

Selection sort

Pseudocode

Easier to code than other sorts Good enough for small amounts of data Performs the same, no matter how the data is unsorted. No. of Passes (how many times it looks at the whole array) n-1 (n is the number of indexes in the array.) No. of Swaps (how many times data is moved in the array) n-1 No. of Comparisons (checking if a value is smaller or larger) N² Selection sorts are overall not very good for most situations.

Algorithm: Look at each item in the array, starting at first value (index 0) Find smallest value (if sorting small to highest values) Swap with the value at index (0) Look at each item in array, starting from the next index (index 1) Find smallest value Swap with the value at index (1) etc.

Selection-Sort-Animation.gif

Term: Pass Counted each time an array is cycled through Comparison Two array elements are compared to each other Swap When two array elements are moved within the array.

Sorting data in an array is effected by

The complexity of the sorting algorithm

How many items there are to sort

How unsorted the data is

Processing features of a programing language

Control Structures (a block of code that controls which lines of code executed)

Iteration / Repetition (Loops)

Differences between for, do, while

Selection (If)

Sequence (Code running line by line in order)

Subtopic

Functions (A procedure that returns a value that can be used elsewhere)

return a result

perform some instructions

can be passed

Method ( an action that DOES something to a variable, object, class)

Procedures (Multiple lines of code that do something (method in C#)) -a set of instructions

modular programming - breaking codes into procedurea

can be called at anytime

prevent duplication

debugging easier

Instruction (a line of code)

Data structures (a way to store multiple pieces of data) data element: variables(one variable is not a structure), arrays, records

variables (one variable is not a structure)

records

why use records instead of arrays? =>Each array does not make much sense on its own -need to access the ‘name’ and ‘MobNo’ array to see who the number belongs to. =>Sorting arrays like this becomes hard -How do you keep the indexes and values lined up between arrays?

example

contain variables of different data types

group variables together for a particular purpose or to describe a particular object.

associative arrays

includes _Hash tables _Dictionaries

Dictionaries

Hash tables

A hash function generates an index to store data, based on a key Collisions can occur if a hash function produces the same index from different keys. Searching would return the index value of where the data is stored each time - no linear or binary searching required.

data stored as: key : value pairs

purpose: organise data -> retrieval easier, esp for large data

One dimensional arrays

-only store values of the same data type, that are referenced with an index. -usually start at 0 (beware: can start at 1 if the question says so )

4) Evaluation

Note: Evaluation = did the solution meet its goal? Completed AFTER the solution has been deployed Conducted by the users and organisation Relate back to system goals, objectives Can use measured in terms of Efficiency and Effectiveness
Report
findings must be presented in the form of a written report.
Strategy
Using evaluation criteria in the Design stage --> evaluate efficiency and effectiveness during design
Collect information using Surveys, Interviews, Observations - just like collecting data for the solution requirements activity.

Technique for collecting data

Observations

Watching and recording how a system is used, or how it performed. Unobtrusive Time consuming Must choose appropriate time to observe Users may behave differently if they know they are being observed.

Surveys

Structured questions Multiple-choice Scale Short answer, long answer text Easier to process, not as detailed Short time taken for multiple responses Some people don't like filling in surveys People sometimes write down what they THINK they do, not what they ACTUALLY do. Online (Google Forms)

Interview

Qualitative data Prepared questions, but can elaborate or move onto other topics Harder to process Takes more time, especially for multiple interviews. Voice recorder, camera etc.

information to collect

Information about the current system: What is the current system used for? What works? What doesn’t work? What does the new solution need / require? (Solution Requirements)

How well has the solution met its goals?

2) Design

Evaluation criteria
effectiveness

usability (is software easy to use?)

relevance (is output relevant to required functions?)

communication of message (is it easy to understand info?)

timeliness (is it up-to-date?)

accessibility (does solution cater to people with disabilities?)

accuracy (is output correct and precise enough?)

attractiveness (does solution look good?)

readability/clarity (is it easy to read the output?)

completeness (does required info get produced?)

efficiency (cost/time/effort)

less cost/time/effort = better

cost of file manipulation

use more efficient algorithm

minimise time taken by solution to change files

functionality

does app address the tasks it was designed for?

output generated at reasonable time?

can data be entered quickly?

Solution design
Styles of application architecture

Internet

Example: Google Docs

Most processing occurs on the server, rather than the user computer.

require the use of the internet to function.

Peer to Peer

No connection to a central server

processing and data are shared between peers (users).

Rich Client

Example Microsoft Word

requires some connection to a central server.

does most of the processing of data on the client (users) computer.

Mobile

Usually, will not require internet connection to function (apart from the initial download).

Interface needs to be designed to work with touch input. Larger icons, less text on interface

Mobiles devices, such as smartphones and tablets.

factors influencing design

marketability (easy to sell?)

improve marketability by improving above factors + effiviency and effectiveness

how easy will software be to sell?

measure of how much can be sold

interoperability (work with other systems? aka portability)

must be compatible with other software packages (e.g. data in XML works with other programs)

security (also affects coding)

authentication

Single-Sign-On (SSO)

Login - Username and Password

data protection

must comply with Privacy Act

needs to protect sensitive data

encryption

affordability (cost/development budget enough? reasonable price for user?)

usability (easy to use? target audience?)

design tools

mock-ups

Hand drawn visual representation of the solution. Provides the layout and relative positioning of all controls on a form. Labelled to indicate how the solution is used.

data dictionaries

Data dictionary example

defines all data elements (variables and arrays) in program

size (no. of characters)

data type (characterised by the kind of operations)

Note: Correct data type benefits: -efficient use of storage (e.g integers use less memory) -speed up performance -calculations can be performed?

boolean

True/False only

character (cannot use for calculations)

string

Examples: John Computer ID785342 mark@telstra.com.au 0407897235 - a 0 at the front cannot use a numeric data type!

a collection of individual characters (Any single alphanumeric characters and symbols)

numeric (can use for calculations)

date

Stores date and time values DD/MM/YYYY, HH:MM:SS.MS

double

Any number, including decimals up to 15-16 digits greater precision than a float

floating point

Any number, including decimals of up to 7 digits greater precision in stored values

integer

Whole numbers (+/-)

purpose of data

name of variable

pseudocode (before coding)

Note: EXPECTED outcome is based on the description of the algorithm in the question stem The ACTUAL outcome is based on the pseudocode algorithm.

Structured English Write down the methods for your program to describe it Language independent You should be able to read an algorithm in pseudocode, then write the algorithm in any programming language you are familiar with.

iteration (loops)

loop through an array

For i = 0 to len(arr)

For/EndFor (for loop)

While/EndWhile (while loop)

Repeat/Until (do loop)

selection (if statements)

Must Endif

indent code

If/Then/ElseIf/Else/EndIf

assigning values to variable

name ← user input

age ← 16

to access file contents

Until End of File (do loop)

While Not End of file (while loop)

keywords are bold

Pseudocode summary

object descriptions

describes objects/controls in solution

formatting info (font, size, colour, alignment)

attached procedures/functions

purpose

type

name of control

Reasons for using design tools _Represent solution before development begins _Generate, brainstorm faster _Ensure meeting the requirement of the client

1) Analysis

SRS (Software requirements specification)
Content of an SRS
SRS is done during analysis
_breaking down a problem into component parts _providing input to the design stage _serving as a reference point for further stages of the problem-solving methodology.
Scope of solution (describes the boundaries or parameters of the solution)
list of what the program cannot do
list of what the program can do
Solution constraints
usability

ease of use

usefulness

legal

privacy

copyright

social

users' level of expertise

technical

security

compatibility

availability of equipment

capacity (storage)

speed of processing

economic

time (how much time do we have?)

cost (how much money do we have?)

Solution requirements
Analysis Tools

use case diagram

UCD symbols

Data flow diagram (shows movement of data)

DFD symbols

Context diagram

interaction between the organisation and external entities

non-functional

attributes

reliability (same output every time?)

portability (work in/ move to different environment?)

robustness (no crashing?)

maintainability (easy to update/add?)

usability (easy to use?)

functional

functions

Validation

Data manipulation (process)

output

input

xml file formats

Easy to edit and read by humans and software. XML is CASE sensitive. XML is an open-source file format. XML files can be directly edited with a Text Editor (Notepad), or by instructions written in an application. XML tags cannot start with a number, xml, or have spaces.

XML = eXtensible Markup Language XML files are used to store and transport data between software. provides a common structure for sharing data between applications. Uses tags to describe data, similar to HTML. CSV (comma separated value) files are similar, but only contain raw data, whereas XML files have field names and structure. XML files give structure - they show which pieces of data relate to each other through indentation.