Lecture 24: Human Systems Requirements

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Lecture 24 Human Systems Requirements
Readings Chapter 8 of Chapanis (1996)
09/10/99
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Goals

• Show how Human System Requirements flow from the
  physiological and psychological properties of
  people
• Discuss relationship between requirements and
  standards
• Discuss how to identify requirements based on
  operational and task analysis

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What are Human Requirements?

• a way of steering designers away from bad
  solutions
• One of the many types of requirements designers
  may have to face
• Documents (specifications) that designers follow

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Example Workspace for a Knowledge Worker

• What is the relative vertical position of the
  hands and elbows when typing?
• What is the angle of the knees when sitting at
  the workstation?
• Is there enough legroom? etc.

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Workspace Components
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Human Spatial Requirements (Anthopometry)

• Fit
• Reach
• Support
• Posture
• Visibility
• Safety

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Human Requirements for a Computer Workstation
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Key Issues

• visual angle between eye and monitor
• leg clearance
• position of elbows and hands
• position of the foot.

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Requirements should be Detailed

• Side View
• Overhead View
• Close-ups
• Sitting vs. Standing
• Different Versions for Different Types of
  Workstation

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Sketches and Layouts

• Frequently used in human factors engineering
• to specify requirements
• to assess suitability of workstation designs.
• Can be supplemented with written descriptions

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Design requirements must be

• Precise
• Project specific
• Stated in verifiable form
• Stated with different amounts of specificity

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Where do you get Requirements from?

• Standards
• Design Guidelines and Handbooks
• Analysis and Measurement
• Operational and Task Analysis

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Coverage of Requirements

• General
• More flexible
• Project-Specific
• Focused on the specific project
• More precisely defined
• Be careful in borrowing requirements from
  similar projects

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Kinds of Requirement

• System access requirements
• Personnel requirements
• Training requirements
• Workspace requirements (dimensions, doors, etc.)
• Work requirements (environmental factors etc.)
• Interface requirements (controls etc.)
• Task requirements (e.g., work-rest)

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Different Kinds of Requirements

• Human requirements
• Low power utilization
• Cost of payload
• Thermal properties
• Etc.

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Tradeoffs between Requirements

• Fitting more workstations into a small space
• Human requirements vs. cost of space
• Guarding robots on a factory floor (more
  expensive)
• Speed of emergency vehicles
• Design of car seat for comfort vs. alertness

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Lessons

• Requirements guide design
• Human requirements flow from operational and task
  analysis
• Human requirements also flow from standards and
  guidelines as applied to the results of task and
  operational analysis
• Different types of requirements
• Need to assess tradeoffs between requirements