USER INTERFACE

OVERVIEW

What is Human Computer Interface (User Interface)

principles of user interface design

What makes a good Interface

Why should we care about UI?

GROUP MEMBERS

Abdulsemed Lezin

Habab Sadam

Michael Gebre

Ferhan Hussen

Amente Nigussie

WHAT IS UI?

Visual part of computer application or operating system through which a

user interacts with a computer or a software.

It determines how commands are given to the computer or the program and

how information is displayed on the screen.

Three main types of user interfaces are

(1) Command language: the user must know the machine and program-

specific instructions or codes.

(2) Menus: user chooses the commands from lists displayed on the screen.

(3) Graphical user interface (GUI): user gives commands by selecting and

clicking on icons displayed on the screen.

THE USER INTERFACE

System users often judge a system by its interface rather than its

functionality

A poorly designed interface can cause a user to make catastrophic

errors

Poor user interface design is the reason why so many software

systems are never used

Most users of business systems interact with these systems through

graphical user interfaces (GUIs)

In some cases, legacy text-based interfaces are still used

GRAPHICAL USER INTERFACE (GUI)

Graphical User interfaces rely much more heavily on the mouse. A

typical example of this type of interface is any version of the Windows

Operating System. The main advantages are:

1. Less expert knowledge is required to use it (more user friendly)

2. Easier to navigate.. can look through folders quickly in a guess

and check manner.

The main disadvantages are:

1. Typically decreased options (less powerful)

2. Typically less customizable. Not easy to use one button for tons of

different variations.

Graphical User Interfaces are more common than text-based

interfaces in modern computing.

GUI ADVANTAGES

They are easy to learn and use.

Users without experience can learn to use the system

quickly.

The user may switch quickly from one task to

another and can interact with several different applications.

Information remains visible in its own window when

attention is switched.

Fast, full-screen interaction is possible with immediate access to

anywhere on the screen

PROBLEMS

Actions involving logical conjunction (and) or disjunction (or) are

awkward to represent

If there are many choices, some menu structuring facility must be used

Experienced users find menus slower than command language

USER INTERFACE EVALUATION

Some evaluation of a user interface design should be carried out to

assess its suitability

Full scale evaluation is very expensive and impractical for most

systems

Ideally, an interface should be evaluated against a usability

specification

However, it is rare for such specifications to be produced

ELEMENTS OF USER INTERFACE

To perform user interface analysis, the practitioner needs to study and

understand four elements

The users who will interact with the system through the interface

The tasks that end users must perform to do their work

The content that is presented as part of the interface

The work environment in which these tasks will be conducted

THANK YOU

TYPES OF USER INTERFACE

There are two main types of user interfaces:

1. Text-Based User Interface or Command-Line

Interface

2. Graphical User Interface (GUI)

TEXT-BASED USER INTERFACE

This method relies primarily on the keyboard. A typical example of this

is UNIX. The main advantages of a Text-Based User Interface are:

1. Many and Easier to customization options

2. Typically capable of more powerful tasks

The main disadvantages of a Text-Based User Interface are:

1. Relies heavily on recall rather than recognition.

2. Navigation is often more difficult

GRAPHICAL USER INTERFACE (GUI)

Graphical User interfaces rely much more heavily on the mouse. A

typical example of this type of interface is any version of the Windows

Operating System. The main advantages are:

1. Less expert knowledge is required to use it (more user friendly)

2. Easier to navigate.. can look through folders quickly in a guess

and check manner.

The main disadvantages are:

1. Typically decreased options (less powerful)

2. Typically less customizable. Not easy to use one button for tons of

different variations.

Graphical User Interfaces are more common than text-based

interfaces in modern computing.

PRINCIPLES OF USER INTERFACE DESIGN

The principles of user interface design are a way to improve

the quality of user interface design.

According to Larry Constantine and Lucy Lockwood in their

usage-centered design, these are principles of User Interface

Design

UI DESIGN PRINCIPLE CONT..

The structure principle:- Design should organize the user interface

purposefully, in meaningful and useful ways based on clear, consistent

models that are apparent and recognizable to users, putting related

things together and separating unrelated things, differentiating

dissimilar things and making similar things resemble one another. The

structure principle is concerned with overall user interface architecture.

CONT..

• The simplicity principle: - The design should make simple,

common tasks easy, communicating clearly and simply in

the user's own language, and providing good shortcuts that

are meaningfully related to longer procedures.

CONT..

The visibility principle: The design should make all needed options and

materials for a given task visible without distracting the user with

extraneous or redundant information. Good designs don't overwhelm

users with alternatives or confuse with unneeded information.

The feedback principle: The design should keep users informed of

actions or interpretations, changes of state or condition, and errors or

exceptions that are relevant and of interest to the user through clear,

concise, and unambiguous language familiar to users.

CONT..

The tolerance principle: The design should be flexible and tolerant,

reducing the cost of mistakes and misuse by allowing undoing and

redoing, while also preventing errors wherever possible by tolerating

varied inputs and sequences and by interpreting all reasonable actions.

The reuse principle: The design should reuse internal and external

components and behaviors, maintaining consistency with purpose

rather than merely arbitrary consistency, thus reducing the need for

users to rethink and remember.

LAWS OF UI DESIGN

According to Jef Raskin in his book The Humane Interface, there are

two laws of user interface design

1, First Law: - A computer shall not harm your work or, through

inactivity, allow your work to come to harm.

2, Second Law: - A computer shall not waste your time or require

you to do more work than is strictly necessary.

Jef Raskin also mentions that "users should set the pace of an

interaction," meaning that a user should not be kept waiting

unnecessarily.

THANK YOU

WHAT MAKES A GOOD USER INTERFACE?

A good interface makes it easy for users to tell the computer what

they want to do, for the computer to request information from the users,

and for the computer to present understandable information. Clear

communication between the user and the computer is the working

premise of good UI design.

Good interfaces are: Clear

A clear interface helps prevent user errors, makes important information

obvious,

and contributes to ease of learning and use.

ConsistentA consistent interface allows users to apply previously learned knowledge

to new tasks.

Effective applications are both consistent within themselves and consistent

with one another.

SimpleThe best interface designs are simple. Simple designs are easy to learn

and to use and give the interface a consistent look. A good design requires a

good balance between maximizing Functionality and maintaining simplicity

through progressive disclosure of information.

User-ControlledThe user, not the computer, initiates and controls all actions.

DirectUsers must see the visible cause-and-effect relationship between the actions they

take and the objects on the screen.

This allows users to feel that they are in charge of the computer's activities.

ForgivingUsers make mistakes.

User actions should be reversible.

A good interface facilitates exploration and trial and

error learning.

Provide feedbackKeep the user informed and provide immediate feedback.

Also, ensure that feedback is appropriate to the task.

AestheticEvery visual element that appears on the screen potentially competes for the

user's attention. Provide an environment that is pleasant to work in and

contributes to the user's understanding of the information presented.

THANK YOU

4. WHY YOU SHOULD CARE

4.1 Finance

4.2 Impact

4.3 Ethics

4.1 FINANCE

Cost savings of usability testing.

For commercial organizations, greater usability leads to increased sales

and greater competitive advantage.

FINANCE(CONT..)

• For non-profits, “conversion rates” (e.g. transforming a casual

user to a signed-up and engaged user) are still important: a

resource that addresses the needs of its users is more likely to

lead to greater use and (repeated) engagement.

• Reduce support costs.

4.2 IMPACT

• Increased user engagement in design This can lead to more

user-focused resources which in turn can increase a

resource’s impact.

• Impact important consideration when creating funding

applications.

4.3 ETHICS

• All resources have users or potential users.

• Jef Raskin, The Humane Interface (2000): laws of interface design:

• A computer shall not harm your work or, through inactivity, allow your work to

come to harm.

• A computer shall not waste your time or require you to do more work than is

strictly necessary.

USER INTERFACE (ADVANTAGE AND DISADVANTAGES)

Graphical User Interface

Menu Driven Interfaces

Command Line Interface Applications

ADVANTAGES (GUI)

It can be user-friendly and speed up the user's work.

It can be more attractive for non-technical people.

In general, it looks more professional (but this does not mean it is

always the best solution).

DISADVANTAGES

When it is not properly built, it can be very difficult to work with.

It generally requires more memory resources than a non-graphical one.

It might require the installation of additional software, e.g., the "runtime

environment" in the case of java.

Depending on the programmer, it might require more time to be implemented.

MENU DRIVEN INTERFACES

Menu Driven Applications

• ATM

• Mobile Phone

• MP3 Player

• Video recorder

• Household Devices

• Digital/Cable TV

ADVANTAGES (MENU DRIVEN INTERFACES)

No need to learn complex commands/language

Easier for a novice to learn/use

Ideal when there are a limited number of options (efficient)

DISADVANTAGES

• Can be frustrating for experienced users i.e. the command

they want to use is buried 5 levels deep!!!!

• User interface may be limited by screen space and number

of options available

COMMAND LINE INTERFACE APPLICATIONS

System administration

Engineering applications

Scientific applications

And for other specific application

ADVANTAGES (COMMAND LINE INTERFACES)

Very flexible with the use of “switches” (options)

Good for “expert” users - can quickly access commands

Uses the fewest system resources

COMMAND LINE INTERFACES(DISADVANTAGE)

Requires the user to learn “complex” commands or language

“Hidden” features i.e. if you don’t know the commands you wont know

the features are there!

Not very good for novice users