university of southern california center for software engineering cse usc scrover increment 3 and...

University of Southern CaliforniaCenter for Software EngineeringC S E

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SCRover Increment 3 and JPL’s DDP Tool

USC-CSE Annual Research ReviewMarch 16, 2004

Barry Boehm, Ray Madachy, Jesal Bhuta, Eric Gradman, LiGuo Huang, Alex Lam,

Steve Meyers, Gustavo Perez, Vincent Rosso

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University of Southern CaliforniaCenter for Software EngineeringC S E

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HDC Project Background• Continuing USC research on the NASA/CMU

High Dependability Computing (HDC) Program– Research on dependability-enhancing technologies

(e.g. formal methods, model checking, architecture analysis, human factors, code analysis, testing, etc.)

– Empirical technology evaluation

• Testbeds are used to exercise new technologies under relevant mission conditions– Provide an organized archive of empirical data

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SCRover Overview• SCRover is an ITAR-safe testbed that uses JPL’s

Mission Data Systems (MDS) technology– MDS is a systems engineering methodology and software

toolset

• Goal: Make SCRover representative of Mars Science Lab (MSL) mission to evaluate dependability strategies– Reference mission is post-earthquake campus safety

monitoring

• Model SCRover on DDP risk tool to match MSL– Bridge the gap between results on technologies’ defect

reduction capabilities and assessments of their impact on dependability attributes

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SCRover

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Increment 3 Plan• Complete requirements this spring

– Obstacle avoidance• Use camera images and laser range finder to detect and maneuver around

– Target sensing and data processing• Visit points of interest along path to target

– Multi-user goal-conflict resolution• Find best path to maximize points of interest within power constraints

• Deliver in Q4• Developers: Eric Gradman, Alex Lam and Vincent

Rosso– Currently working on camera, power adapter, and goal-

conflict resolution algorithms

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DDP Background• Defect Detection and Prevention (DDP) is a

risk management framework– A systematic, continuous, top-down approach to

risk management– Embodied in a software tool

• Widely used in JPL, not including the software domain– USC collaboration for HDC is the first extensive

application for software risks– Results will be used by JPL for downstream

mission planning– Win-Win for all

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DDP Concepts

• Three linked tree structures for requirements (mission objectives), risks and mitigations– Risks related to requirements

• Indication of how much each risk impacts each requirement

– Mitigations related to risks• The effect of each mitigation on each risk

• A set of mitigations achieves benefits and incurs costs

• Facilitates the selection of a set of mitigations to attain requirements in a cost-effective manner

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SCRover Risk Model Portions

Risk

Mitigationsdata value not assigned

buddy checking 0.4formal peer reviews 0.8walk-throughs 0.7pair programming 0.7perspective based reviews 0.8

effectivenessmatrix showingdefect reductionpercentage

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SCRover Sample DDP Output• Green indicates risk reduction from selected mitigations

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DDP Acknowledgements and Demonstration

• JPL personnel collaborating on DDP include Steve Cornford, Martin Feather, Al Nikora, Leila Meshkat   

• Demos presented here by Steve Meyers