Administracion

Human Interface/ Human Error
18-849b Dependable Embedded Systems Charles P. Shelton February 25, 1999
Required Reading: Murphy, Niall; Safe Systems Through Better User Interfaces SupplementalReading: Burns, A.; The HCI component of dependable real-time systems Authoritative Books: Reason, James; Human Error Nielsen, Jacob; Usability Engineering

Overview: Human Interface/Human Error
x xIntroduction Key concepts
• Sources of Human Error • HCI problems • Usability versus Safety

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Techniques for User Interface Evaluation
• Inspection Methods • Empirical Methods

x xRelationship to other topics Conclusions & future work

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YOU ARE HERE
Maintenanc e and Reliability

Human Interface/ Mistake s

VERIFICATION/ VALIDATION/ CERTIFICATION
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Introduction
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“Human error” is the source of most problems in any embedded system System Design Errors
• Incomplete specifications • Design defects • Implementation errors (bugs in software, manufacturingdefects)

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Errors from the operator or Human-Computer Interface (HCI)
• • • • Poorly designed user interface Operator error Maintenance errors Designing HCI to provide appropriate response andfeedback for the operator and minimize and compensate for operator error
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Sources of Human Error
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Passive humans are the failsafe when errors occur
• Operator is removed from control of thesystem, but expected to prevent system breakdowns • People have short attention spans and will adapt to common case • If system usually works without their intervention, they will be slow to react toexceptional conditions

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Humans make more mistakes under stressful conditions
• But are the only part of the system capable of dealing with truly exceptional conditions

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Repetitive tasksencourage mistakes
• When you perform a task you’ve done a hundred times before, you don’t pay attention and will tend to make more mistakes
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Stress Factors
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Human performance will...