design for usability human factor system engineering and analysis

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design for usability (human factor)system
engineering and analysis

• 990916 im jae hyoun

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introduction

• for a system to be complete, one needs to address
  the human being and the interfaces between the
  human and other systems elements
• good hardware and software design alone will not
  guarantee good usability
• consideration must be given to the user's
  anthropometic characteristics, sensory factors,
  physiological factors, psychological factors and
  their interrelationships
• identification of functions and tasks that are to
  be performed by the human, the establishment and
  allocation of human factors design criteria, the
  accomplishment of human factors analysis, the
  identification of personnel and training
  requirements, and the conduct of personnel test
  and evaluation activities

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definition and explanation of human factors

• requirements for the human are derived through
  the descriptions of missions to be performed
• operational and maintenance functions are
  identified indicating the "whats"
• determining the "hows" through subsequent process
  of synthesis, analysis, and evaluation
• given the functions that have been identified and
  allocated to the human, the next step is to break
  these down into job operations, duties, tasks,
  subtasks, etc
• need to address some of the environmental and
  personnel factors that will ultimately influence
  work accomplishment
• personnel factors may be categorized in terms of
  anthropometic factors, sensory factors,
  physiological factors and psychological factors

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anthropometric factors

• when establishing basic design requirements,
  particularly regarding human activities, one must
  consider the physical dimensions of the human
  body
• body dimensions will vary somewhat from a static
  position to a dynamic condition
• when considering various system design
  alternatives, the designer must be aware of the
  different human profiles that are likely to occur
  in the performance of operator and maintenance
  activities
• two basic sources of data regarding information
  on body measurement
• anthropometric surveys
• experimental data
• application of anthropometric data involves many
  consideration
• human body
• work space dimension
• criteria covering specific facets of the objects
  to be designed

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human sensory factors

• vision
• consider degrees of possible eye and head
  rotation
• the eye sees different objects from different
  angles sees different parts of the spectrum with
  varying degrees of brightness
• relative to color, ones perception decreases as
  the viewing angle decreases
• performance is highly dependent on the level of
  illumination

• hearing
• need to address both requirements for oral
  communication and the aspect of noise
• character of noise steady or intermittent
• noise generated by the system (or generated
  externally) must be maintained at a level where
  human efficiency is maximized

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physiological factors

• effects of environmental stress on the human body
  while performing system tasks
• temperature extremes
• humidity
• vibration
• noise
• etc
• external stress factors result in individual
  human strain with impact on one or more body
  systems
• circulatory system
• digestive system
• nervous system
• respiratory system
• etc

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psychological factors

• psychological factors pertain to the human mind
  and the aggregate of emotions, traits, and
  behavior patterns as they relate to job
  performance
• psychological factors may be highly influenced by
  physiological factors
• one's attitude, initiative, motivation, and so
  on, is dependent on the needs and expectations of
  the individual
• designer needs to understand capability and
  abilities of the human relative to the
  information processing requirement
• information processing
• sensing subsystem
• storage subsystem
• information processing subsystem
• response subsystem

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the measures in human factors

• in addressing personnel requirements, the system
  should be able to be operated and maintained by
  an existing group of personnel, where the skill
  level requirements are held to a minimum
• anthropometric factors provide design-to guidance
  where the human is involved in performing system
  functions
• volume and rate of information processing serve
  as measures in the design of communication
  subsystems
• the objective is to establish system design
  criteria that will promote simplicity in
  operation
• resulting in minimized personnel training cost,
  reduced probability of personnel-induced system
  failure, minimized overall life cycle cost

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human factor in system life cycle

• human factors must be an inherent consideration
  within the overall systems engineering process
• beginning with the conceptual design, the
  designer must conduct some initial trade-off
  studies to determine the extent to which the
  human will be involved in the operation of the
  system, considering the criteria discussed
  earlier
• as an iterative part of system synthesis,
  analysis and evaluation human factor analysis
  should be incorporated into the system
  engineering process
• operator task analysis
• operational sequence diagram
• error analysis
• safety/hazard analysis
• mockups

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personnel and training requirements

• personnel quantities and skill levels are
  determined for all human activities by function,
  job operation, duty and task, then eventually for
  the system as an entity
• given the personnel requirements, the next step
  is to identify available resources
• these resources are evaluated relative to their
  current skill levels as compared to the skill
  level necessary. the differences dictate the need
  for training
• with the objective in mind a formal training plan
  should be developed and implemented in time to
  support system operation and maintenance
  activities as the system is distributed for use
• iterative evaluation of human performance
  efficiency

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reference

• system engineering and analysis
• 3rd edition
• benjamin s. blanchard wolter j. fabrycky