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Behavioral – Cognitive Methods. System Design, Development & Testing. Basic HFE definitions Human-Machine System What are the basic elements of a system that must be considered during system development?
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System Design, Development & Testing • Basic HFE definitions • Human-Machine System • What are the basic elements of a system that must be considered during system development? • Where do the concepts of safety management, biomechanics, anthropometrics, human modeling, human capabilities and limitations, system performance requirements, system component performance, procedures, management processes, cost, life cycle, (etc.) apply?
General Characteristics of Systems Development • Molecularization • Requirements as Forcing Functions • System Development as Discovery • System Development as Transformation • Time • Cost • Iteration • Design Competition • Priorities • Relevance • Design Reviews
Behavioral Inputs • Selection and acquisition of system personnel • Personnel training related issues • Inputs affecting design of system hardware, software and procedures • Inputs related to testing
Behavioral Questions during System Development • Feasibility Analysis and Program Initiation • Demonstration/Validation • Full-Scale Engineering Development • Production/Deployment
Function Analysis • Basic Approaches • Terminology • Uses of Functional Analysis • Hierarchical Nature • Methods of Representation
Flow Analysis • Progressive travel (personnel or material) from place to place and/or operation to operation (may include information flow) • Process Charts • Represent the flow of events and activities (functions) involved in system performance • Questions about functions • Operation Process Charts • Flow Process Charts
Flow Diagram • Symbolically represent the various functions in some process • Diagrammatically or drawing based • Representative of function’s setting • Demonstrates various steps in procedure completion
Operational Sequence Diagram • Depicts graphically the information-decision sequences in a system necessary to complete a mission or task • Three uses: • Establish sequence-of-operations requirements • Depict logical result of decision-action sequences • Evaluate panel layout/workspace design
Functional Analysis Systems Technique • FAST charted as verb,noun two-word statements defining functions • Similar to OSD, focus on defining functions and related sequences • Not dependent on standard symbols; uses verb-noun descriptions instead • Statements placed in boxes to demonstrate sequence
Gang Charts • Developed to simultaneously represent more than one sequence of events or activities • Multiprocess or multiple activity charts • Left-hand, right-hand • Gang charts • Triple resource charts
Time-Line Analysis • Analytical technique that focuses on human performance deviations based on both functional and temporal loading • Requirements can be extended to system elements (vehicles, machines, equipment, computers) • Used for workload prediction, analysis, allocation, scheduling
Network / Link Charts & Procedures • Network Analysis • Link Analysis • Network Diagrams • Mathematical Procedures • Task Network Modeling
Background/Application • Process by which design team allocates jobs, tasks, system functions, responsibility to human-system components (human, machine, automation) • Considers the relative strengths and weaknesses of each system component • Automation is changing the nature of FA; its benefits and limitations are becoming clearer
Task Analysis Stakeholder analysis for FA Analyze alternative allocations Human-computer (automation) capabilities – H, H-C, C-H, C Review allocation results Explore alternatives Procedure
Provides structure for automation decisions Process ensures automation decisions are traceable Helps ensure system user will not be inappropriately delegated the role of monitor/supervisor of an automated system Cost on large scale systems (consider the entire ROI) Requires familiarity and expertise with both human factors, human performance, and system design Requires access and participation of system stakeholders Advantages/Disadvantages
Related Methods • Task Analysis • Sociotechnical systems analysis • Stakeholder analysis • Safety Management Systems (SMS)
Analyst familiarity with background methodologies Experience dealing with human factor Usually involves entire design team (technical, hardware, software, users, HF personnel, safety, IT, maintenance) Simple FAs are fairly straightforward and inexpensive Cost can increase almost exponentially with system complexity Remember the cost of NOT properly allocating functions Training/Application
Considerable debate about validity of FA Some think process is deeply flawed (Jordan, 1963; Fuld, 2000) Two main problems Failure to coordinate theoretical system FA with practical context No evidence that misallocation has led to failure (not valid anymore) No real measures of validity yet. Reliability and Validity
Tools • Paper and Pencil • Automated tools and aids have been developed to facilitate • Need for design documentation to audit decisions about FA
Function Allocation in Manufacturing • Automation, Robotics and Flexible Manufacturing Systems (FMS) • What biomechanics issues do these technologies introduce? • What are the issues that must be investigated? How would you investigate them? • Do the older methods of allocation still apply? • Concepts of Design for Automation (DfA) and Dynamic Function Allocation (DFA)
Task Analysis • Early History • Nature of Tasks in Technological Systems • Definitions • Hierarchical Task Analysis (HTA) • People engaged in the HTA process • Summary of general HTA concepts and terminology
Background/Application • Developed to analyze complex tasks • Originally used for repetitive physical work but has been modified to cognitive/knowledge based method due to changes in automation • Analysis at the Goal/Operations level • Operations decomposed to identify potential for operational failure • INPUT – ACTION – FEEDBACK • Task decomposition to level of sensible analysis
Purpose of Analysis Task Goals & Performance Criteria Sources of Task Info Acquire Data/Draft Decomposition Table/Diagram Recheck Decomposition Data Identify Significant Operations Generate & Test Hypothetical Solutions Procedure
Widely adaptable Flexible in terms of detail based on purpose Exhaustive in its ability to address a problem Requires considerable training Requires human performance and human factors knowledge Requires full participation and collaboration of stakeholders Significant time and cost Advantages/Disadvantages
Related Methods • Task Analysis for Error Identification (TAFEI) • Systematic Human Error Reduction and Prediction Approach (SHERPA) • Method for Usability Engineering (MUSE) • Sub-Goal Template (SGT) • Task Analysis for Knowledge-Based Descriptions (TAKD)
Training/Application • No formal training although requires considerable experience both with the system, organization, users as well as human factors methods and principles. • Level of experience can determine level of analysis quality • Work as a team at first or with an experienced human factors professional your first time
Reliability depends on care taken in data acquisition (trash in-trash out) Don’t downsize recheck stage. Validity depends on selection and addressing the “correct” or appropriate question. The question asked in some ways defines the solution derived from this process No sufficient data on Validity Reliability and Validity
Tools • Pencil and Paper method • May use data from interviews • Tape or video record task performance • May want to use a software tool that support group think/group decision making • Video tape team or individual behavior in critical operations • Don’t fall off the airplane
Cognitive Task Analysis • Next Time !!!