Extending Training Capability Through The Use of Embedded Domain-Specific Languages in Training Devices

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Extending Training Capability Through The Use of
Embedded Domain-Specific Languages in Training
Devices

• John Aughey

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Point of this discussion

• Incorporate a scripting language into all
  software
• Leverage that embedded scripting language during
  development
• Expose that language to the end user
• Allow end users to use this language to extend
  and enhance usability

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Typical Flight Training Simulator
Instructor/Operator Station
Crew Station
Real-Time Host
Tactical Environment
Threat Stations
Brief/Debrief System
Visual System
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System of Systems
Collaboration of many systems
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Examples of embedded domain-specific languages
Internet Browsers
3-D Modeling
Interactive Content
Spreadsheets
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(No Transcript)
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Available Scripting Languages

• Ruby
• Perl
• Python
• ECMAScript
• LUA

• Smalltalk
• Tcl
• Ch
• RBScript
• Guile

Dont reinvent the wheel!
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Exposed Interface
Readable, approachable language

1. aircraft.extend_flaps
2. create_threat MIG29, distance gt 3.miles

In contrast to

1. aircraft.digital_inputsFLAPS 2
2. threat_environment-gtaddThreat(new
   ThreatAircraft(MIG_29, aircraft.altitude,
   position_offset(aircraft.latitude,aircraft.longitu
   de,aircraft.bearing,3MILES_TO_FEET)))

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How to Embed

• Frame-based
• Top-of-loop
• SCRIPT(begin)
• Computation
• SCRIPT(end)
• Loop

• Event Based
• Mouse Clicks
• Button Presses
• Weapons Launch
• Entity Damage
• Entity Interaction

Application includes hooks where the scripting
language can control the application.
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Life cycle of Embedded DSL

• Improved Requirements Definition
• Automated Testing
• Rapid Integration
• Simplified User Interfaces
• Extendable Software

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Requirements Definition

• The gear shall not extend above 10,000 feet
• DSL specification
• context The aircraft above 10,000 feet
• setup
• specify should not allow gear to extend

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context The aircraft above 10,000 feet" setup
initial_conditions altitude gt 10000.feet
specify should not allow gear to extend"
aircraft.lower_gear aircraft.gear_should_be
up specify should not allow flaps to
extend" aircraft.extend_flaps
aircraft.flaps_should_be retracted
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Conceptual vs Functional Requirements

• Functional Requirements have a measurable
  behavior
• Conceptual Requirements are difficult to define
  concretely
• User Interface Interaction
• Incomplete Understanding of use case
• Results in over defined or ill-defined
  requirements

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Example

• The operator software must provide a way to
  induce the following failure conditions
• Engine fire
• Loss of rudder control
• COMM failure
• HUD failure
• Defined by curriculum

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Implementation

• Provide the operator a menu with a list of these
  failures, and a button to induce the selected
  failure

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Next software update

• New requirement
• Define a conditional value into the failure menu
  to avoid needing to monitor the altitude
  indicator manually. Other failures might need
  different conditionals for altitude, airspeed,
  orientation, flight time, and so on.
• All of these different possible conditions are
  added to the requirement in lengthy detail.

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Discovered problem

• In practice, however, the operator soon discovers
  the failure event triggers too fast, because the
  instant the altitude hits 20,000 feet, the engine
  fire failure triggers. The training need is
  really engine failure at level flight, so the
  failure really needs to happen as a result of two
  conditions being met, a given altitude and a
  given rate of climb.

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Next software update

• New Requirement
• All failure conditions must have an operator
  defined conditional statement. Once the entire
  conditional statement is satisfied, the failure
  will occur. At least 10 different conditional
  statements must be definable by the operator for
  each failure condition with the option to chain
  the statements together with AND or OR logic
  operators. At least 16 failure conditions can be
  ready to be triggered at any point in the
  training scenario.

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DSL Solution

• Expose the following failure triggers to the
  scripting language
• Engine fire
• Loss of rudder control
• COMM failure
• HUD failure

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Operator Program

• description Fail the rudder 10 seconds after
  wheels-up
• trigger action gt Failures.trigger rudder
  ,
• when gt wheels_up_time gt 10

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Engine Fire Program

• description Trigger an engine fire once the
  aircraft reaches 20000 feet
• trigger action gt Failures.trigger
  engine_fire_left ,
• when gt altitude gt 20000.feet and
  rate_of_climb lt 10.feet.per.second

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Simplified/Extendable User Interfaces

• Push decision making out to the scripting
  language
• Native code
• Processor intensive computation
• Graphics/Rendering
• Device interaction
• Scripting code
• What, where, when, why

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Spot Meter Lab Software

• when_created do
• open_log_file "gammameasurements"
• set_intensity 0
• set_time_of_day midnight
• set_test_pattern "rectangle"
• set_testpattern_size 4.0
• drop_readings 20
• end
• for_each_reading do
• write_log intensity,measured_intensity
• increment_intensity_by 4
• drop_readings 4
• end

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Customer Extendable Software