Matakuliah
Tahun
Versi
: M0086/Analisis dan Perancangan Sistem Informasi
: 2005
:5
Pertemuan 22
Interface
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Mahasiswa dapat Menerangkan kegunaan User
Interface (C2)
• Mahasiswa dapat Membuat diagram / skema
Navigation (C4)
• Mahasiswa dapat Mendesain User Interface
(C5)
2
Outline Materi
• User dan Sistem Interface
• Pola User Interface
• Menentukan pola user interface
3
Aktivitas utama dalam
Analisis Application Domain
System Definition
and model
Interfaces
Usage
Functions
Requirements
(Mathiassen et al, 2000)
4
Terminologi
• Interface: Fasilitas yang membuat model
sistem dan function dapat berinteraksi
dengan actors.
• User interface: Interface untuk users.
• System interface: interface ke sistem lain.
• Usage context: The application domain
characterized by actors and use cases.
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User Interface
• Are very important: they can make or break
system use and benefit realisation.
• Needs to carefully fit the usage context.
• Need to be designed carefully - small details
multiply difficulties with usage.
• Need to account for the different kinds of users
with different skills and capabilities.
• Very difficult to design without feedback generally must be tested with users.
6
Systems Interface(s)
• May need interfaces for non-human actors, i.e.
other systems
• Not commonly used for administrative systems
• More common for monitoring & control systems
– direct sensors in the environment - e.g. temperature
– direct intervention, e.g. motors, switches
– may also input or output from other computer systems
• Need to design and make sure that these
technical connections can be realised
7
Sub-activities in
Interface Analysis
Function
list
Class
diagram
Explore
patterns
Determine
interface
elements
Use cases
Evaluate interface
elements
Describe interface
elements
Description of
interfaces
(Mathiassen et al, 2000)
8
Tailor Usability to Context
• Usage is relative to usage context
Usage context
Desired
properties
Technology
 Routine tasks
 Efficient
 Fixed, well Reliable
structured tasks
 Activation of functions
 Fixed defined dialogue
 Menu and command
driven manipulation
 Non-routine
 Flexible to use
tasks
 Easy to learn
 Varying problem new functions
solving tasks
 Manipulation of objects
 Loosely defined dialogue
 Direct manipulation
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Study the Usage Context
• Study both human actors and use cases
– Does the individual user solve several tasks in
parallel?
– Does the user move physically while working?
– Is the work often interrupted?
– Are certain use cases significantly different from the
typical use cases?
– Do certain work tasks require a quick response from
the computerized system?
– How is it ensured that the users notice when the
computerized system performs a signal function?
10
Explore User-Interface Patterns
• A user interface usually mixes several
patterns or styles
• Four main patterns/styles
– menu
– form filling
– command language
– direct manipulation
• (also natural language)
11
Menu Selection
• Advantages
– Shortens learning
– Reduces key-strokes
– Structures decision
making
– Allows easy support of
error handling
– High level tools allow
for easy programming
• Disadvantages
– Risk of too many
menus
– Slows the frequent
user down
– Consumes screen
space
– Requires rapid display
rate
12
Form Filling
• Advantages
– Simplified data entry
– Requires modest
training
– Makes assistance
convenient
– High level tools allow
for easy programming
• Disadvantages
– Consumes screen
space
13
Command Language
• Advantages Flexible
– Appeals to “power”
users
– Supports user initiative
– Convenient for
creating user-defined
macros
• Disadvantages
– Poor error handling
– Requires extensive
training
14
Direct Manipulation
• Advantages
– Immediately visible
result of interaction
– Useful for both casual
and frequent users
– Can be extremely
efficient
• Disadvantages
– Effort required to
develop
– Difficult to invent
meaningful icons,
symbols, etc., unless
can rely on standard
objects
15
Dialog Style: Function-Oriented vs
Object-Oriented
• Is the interface primarily based on functions or
objects? Need both, but which choose first?
– I.e., does the user choose the function first, then
choose the object or vice versa?
• Function-oriented dialogues are better for routine,
automated work
• Object-oriented ones are better for varied
individual work tasks as they give more flexibility
– But, usually require more development time and effort
16
Some Guidelines
• A dialogue needs to be simple, natural, and
consistent.
• Requirements placed on the users’ memory
need to be minimal.
• Feedback must be informative and constructive.
• Errors must be prevented.
• Detailed discussion is beyond the scope of this
unit.
17
Determine User-Interface
Elements
• Representations of objects in the model
– Many possibilities: icons, fields, tables, diagrams,
windows
– Need a clear & consistent system of representations
• Activation of functions
– Buttons, menu screens, pull-down/pop-up menus
– Also need support for visualisation and feedback
– Needs to be consistent and fit within the dialog
pattern/style
• Result is a list of user-interface elements
18
Describe Interface Elements
• User Interface:
– General effect: colours, fonts, types of menus,
types of icons, default positions
– Navigation: dialog linkages between buttons,
menus, screens, windows, etc.
– Computer screens/windows/forms, etc.:
layout, interactivity, consistency
– Outcome of activity is screen/form designs,
navigation diagram and other descriptions
19
Example Navigation Diagram
(Partial)
Start
Miniature
of screen
or window
Exit
Commands,
menu
selections,
or buttons to
change
screens
or windows
20
Evaluate the User Interface
• A User Interface cannot be constructed bottom
up without experiments using prototypes.
• Should be a carefully controlled process using
the five sub-activities.
• Planning needs to lead to concrete evaluation
and quick development with efficient tools.
• Preparation needs to determine how collaborate
with users, ensure realism, and select good
example tasks that enhance feedback.
21
Explore Systems Interface
Patterns
• Consider what/how data should be sent to
and received from other systems (if any)
• Other systems may be
– simple external devices: sensor, switch, or
motor use simple read or activate device
patterns
– complex computer systems: need a
communication protocol which may be
supplied or need to be designed
22
Read External Device Pattern
• Read either regularly or dependent on an event
Device
connection to
external device
state
Memory
1
read
• Memory object can just be the
1
time
value
measurement
latest-value
model
object
23
Interaction Protocol
• A protocol defines command facilities supporting
the possible use cases for a system by another
• Is agreed upon by designers of the two systems
(unless one has already been designed/built!)
• Specify a pattern for interaction using a list of
commands for each side and their expected
responses
– Separate protocol item named for each command
– E.g. Request some info or Prepare to accept info
– Commands may check the state of the other system
24
Determine and Describe the
Systems Interface Elements
• What other computer systems will the system be
connected to and exchange information with?
– What protocol(s) will be needed?
• Will the system be connected directly to the
problem domain through external devices?
– What external device read or write interfaces are
needed?
• Result is a list and specification of each.
25
Evaluate System Interfaces
• Protocols can be tested on pencil and
paper by working through use cases
• Ultimate test is that the physical
connections actually work
– If there is any doubt, these connections need
to be tested as early as possible
– Build and test technical feasibility prototypes
26
Principles of
Interface Analysis
• Tailor usability to the application domain
– need to know who the users are and in what
situations the computerised system will be
used
• Experiment and iterate
– interfaces are complex and interact with users
in ways that can’t be anticipated
– experiments need to be planned, efficient, and
realistic - and likely will be repeated
27
Principles of
Interface Analysis (2)
• Identify all interface elements
– Important not to leave anything out!
– Details can be supplied/determined later, as
long as the basic structure is clear and
coherent
28
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disewakan, dan member dapat memesan video tertentu untuk di
sewa pada tanggal tertentu.
•Diskusikan Navigation Diagram dan User Interface
29
Terima kasih
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