ITERATION / LOOPING.
Is where a number of statements/block of codes is repeatedly executed until a certain condition is
Iteration is vital in situations where the same operation has to be carried out on a set of
data many times. Iteration also reduc
The Execution, Evaluation Cycle:
The interactive cycle can be divided into major phases:
i. Evaluation Phase
ii. Execution Phase
These are then subdivided into seven stages
Stage 1: User establishes the goal
Stage 2: User formulates the intention
HUMAN COMPUTER INTERACTION
Human Computer Interaction its a discipline concerned with the design, evaluation and
implementation of interaction computing systems for human use and together with the study of
the major phenomena surrounding them.
Is the classification of particular type of information to be used in programming and the
operations that can be carried upon them.
Programming languages like Pascal use the following data types:
1. Integer: Whole number values. Pascal distingu
Usability engineering is a discipline that provides structured methods for achieving usability in
user interface design during product development.
Usability Engineering helps us to achieve usability.
Mayhues model emphasizes usabili
User interface Software Engineering Service Model
Focuses on programming support provided for the implementation of an interactive system.
Programming tools for an interactive system provides a means of effectively translating abstract
Design and usabilit
How a designer can achieve a High Level of Usability
By employing usability principles, or guidelines
Visibility helps users form correct mental models of the 'thing'models that help users predict
the effect(s) of their actions. Important el
It involves embedding of IF statements within another.
For every IF THEN statement, there must be an ENDIF.
IF ELSE <Condition 3> THEN
Technologies for Implementation implementing the U.I
There are two technologies for implementing the U.I
1. Discrete Architecture
2. Implicit Architecture
1. Implicit Architecture
In this technique the code that drives the U.I is tangled with the applicat
Paradigms are predominant theoretical frameworks or scientific world views. They are also
effective strategies for building interactive systems. The evaluation of the usability paradigms
provides a good perspective on the history of
Usability testing aims to achieve the following five goals:
i. To improve the products usability
ii. To involve real users in the testing
iii. To give the users real task to accomplish
iv. To enable testers to observe and receive the actions
Types of Questions used in Questionnaires
1. Scaler Questions: used in Questionnaires
They ask the user to judge a specific statement on a numeric scales usually corresponding to a
measure of agreement or disagreements with the statement.
2. Multi Choice
GOALS OF USERS CENTERED DESIGN
Designing for maximum usability is the goal of interactive systems design. However the
essential principles can summarized by three fundamental goals:
It is the case with which real users can begin effective
It allows statements within the loop (between Repeat & UNTIL) to be executed at least once
since the condition is tested at the end of the loop.
Repeat Until can hold multiple statements using compound statements
Differences between compilers and interpreter.
Translates source program line by line to
machine code equivalent
Slower as it translates the program each
time it runs
Interpreted object takes less space
Interpreters are cheap
What makes a website or piece of software usable
If the design meets the conventional standards, other programmers may be able to understand the
software years later and therefore its usefulness life is elongated.
Error detection and debugging
Usability is part of a broader scope of what makes a system good enough to be acceptable to the
end user and other stakeholders satisfying the needs and requirements of both.
Nielsen Jacob describes usability as a broad concept that refers to ho
Process of testing the functionality and the usability of an interactive system
Goals for Evaluation
1. To assess the extents of system functionality
2. To assess the effect of the interface on users
3. To identity specific problems
Q2. Discuss the following in detail
User-centered design (UCD) is an approach to design that grounds the process in information
about the people who will use the product. UCD processes focus on users through the planning,
Q1. Using well-labeled diagrams, explain how you would develop a system with usable
interfaces in your design. Clearly show all the phases of the design.
Most user-centered design methodologies are more detailed in suggesting specific activities, and
ELEMENTARY PROGRAMMING PRINCIPLES
By the end of the topic, the learner should be able to:
a) Define programming.
b) Describe various levels of programming languages.
c) State the advantages and disadvantages of each level of programming languages.
HIGH LEVEL LANGUAGES
These are machine independent languages coded in human language (English) which is easy to
read and understand.
The instructions closely resemble the human language (English) and mathematical notations.
They are user friendly and prob
A C program that prints a rectangle using nested loop
printf(" * ");
1. What is the output of the following code fragment
SYSTEM AND INTERFACE ARCHITECTURE
The architecture of an interface refers to the look and feel together with the behavior of the
system. Characterized bt dialogue style, structure and content of presentation.
Is the character and control of informat
The For Loop.
The executions of statements are repeated a pre determined number of times i.e. the number of
repetitions is known well in advance.
The loop is controlled by a counter which increases each time a set of instructions is executed.
Stages/modes of error detection
i) Desk checking (dry run)
It involves the programmer going through the program while on paper to pick up any errors that
would otherwise cause extra work at a later stage
The programmer detects the obvious logical and synt
These instructions display/ output data that is in the computer memory.
- Commands used to output data are: PRINT or WRITE
- You can output string variables and numeric variables as follows:
Syntax: PRINT <Variable name>,<Variable name
Four Documents that accompany a full /complete
1. Functional Description manual
It describe briefly the services the system provides
2. An Installation Document
Provides details of how to install the system including information of the disks (CDs) on whic
Where is Usability Applied in a developed system
The User Centered Design activities are broken down into four phases: Usability is applied
in Analysis, Design, Implementation and Deployment.
Are in-inbuilt programs (modules) that perform a single task like calculating a
mathematical expression, then returns a value.
- Each function performs a different mathematical operation e.g. square root, cosine etc.
The programmer can u
OBJECT ORIENTED PROGRAMMING (OOP)
Is a programming that focuses on objects and data rather than the action and logic.
The OOP looks at a program as comprising of various objects that interact to make up a
whole. Historically, a program has been viewed as
A Pascal program
Write a Pascal program that would solve the equation of the straight line i.e. y=mx+c
Line 1: Program StraightLine (i,o);
Line 2: Var
y, m, x, c: integer;
Line 4: Begin
Writeln (Enter the va