THEORY EXAMINATION (SEM–VI) 2016-17 HUMAN COMPUTER INTERFACE

HUMAN COMPUTER INTERFACE (NCS070)

SECTION – A

(Short Answer Questions | 10 × 2 = 20 marks)

(a) Two Stages of Vision

The two stages of vision are:

Physical reception stage, where light enters the eye and forms an image on the retina

Perceptual interpretation stage, where the brain interprets the visual information

(b) Principles of Software Design in HCI

Key principles include consistency, simplicity, feedback, error prevention, flexibility, and user control.

(c) Four Main Translations in Interaction

The four translations are:                                 User goals to actions

Actions to system operations                          System output to display

Display interpretation by the user

(d) Types of Design Rationale                          Design rationale can be:

Informal (notes, comments)                           Formal (structured arguments)

Semi-formal (diagrams, tables)

(e) Principles Affecting Robustness

Robustness is affected by observability, recoverability, responsiveness, and task conformance.

(f) Elements of Windowing Systems

Common elements include windows, icons, menus, pointer, scroll bars, and dialog boxes.

(g) Properties of Windows

Windows can be moved, resized, overlapped, minimized, maximized, and closed.

(h) Cascading Window

A cascading window arrangement displays multiple windows stacked diagonally so that all title bars are visible.

(i) Drivers

Drivers are software programs that allow the operating system to communicate with hardware devices such as printers, keyboards, or mouse.

(j) Function Keys

Function keys (F1–F12) perform predefined tasks.
For example:

F1 – Help                                  F5 – Refresh                     F12 – Save As (in many applications)

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SECTION – B

(Descriptive Questions | Attempt any five | 5 × 10 = 50 marks)

(a) Graphical User Interface (GUI)

A Graphical User Interface allows users to interact with a system using graphical elements such as icons, menus, windows, and pointers instead of text commands.

Importance of GUI:
GUI makes systems easy to learn, reduces user errors, improves productivity, and enhances user satisfaction.

Characteristics of GUI:

User-friendly                                          Visual representation

Direct manipulation                               Consistency

Immediate feedback

(b) Human Memory Systems

Human memory consists of:

Sensory memory – stores information briefly

Short-term memory – holds limited information for short duration

Long-term memory – stores information permanently

Good interface design supports memory by using recognition rather than recall.

(c) Human Characteristics Influencing Interface Design

Important characteristics include perception, attention span, memory limitations, learning ability, motor skills, and user experience level. Interfaces should be designed considering these factors to reduce mental load.

(d) Information Retrieval on Web

Information retrieval on the web involves searching, indexing, ranking, and presenting relevant data to users. Search engines use keywords, hyperlinks, and algorithms to retrieve information efficiently.

(e) Organizing a Display & Getting User Attention

Displays should be organized logically using grouping, alignment, and consistency. User attention can be captured using color contrast, icons, animations, headings, and alerts.

(f) History of Screen Design

Early screen designs were text-based. With time, graphical interfaces evolved, introducing windows, icons, and multimedia. Modern designs focus on usability, responsiveness, and accessibility.

(g) Software Tools

Software tools assist in interface development, testing, and maintenance. Examples include prototyping tools, usability testing tools, and interface builders.

(h) Indirect Pointing Devices and Drivers

Indirect pointing devices include mouse, trackball, joystick, and touchpad. Drivers enable these devices to interact correctly with the operating system.

SECTION – C

(Long Answer Questions | Attempt any two | 2 × 15 = 30 marks)

3. Short Notes

(i) Text

Text is the primary medium for information display. Readable fonts, proper spacing, and contrast improve usability.

(ii) Hypertext

Hypertext allows non-linear navigation using links, enabling users to move easily between related information.

(iii) Multimedia

Multimedia combines text, graphics, audio, video, and animation, making interfaces more engaging and informative.

4. Window Components

(i) Tool Bar

Provides quick access to commonly used commands.

(ii) Split Box

Divides a window into separate sections for viewing different content.

(iii) Command Area

Contains buttons or controls for executing commands.

(iv) Work Area

Main area where user performs tasks.

(v) Menu Bar

Displays menus containing system commands and options.

5. Guidelines for Creating Text for Web Pages

Text should be concise, clear, and scannable. Use headings, bullet points, short paragraphs, readable fonts, and proper color contrast. Avoid clutter and ensure consistency across pages.