A talk given at ACVI 2016. Abstract: Recent research in embedded and cyber-physical systems has developed theories and tools for integration of heterogeneous components and models. These efforts, although important, are insufficient for high-quality and error-free systems integration since inconsistencies between system elements may stem from factors not directly represented in models (e.g., analysis tools and expert disagreements). Therefore, we need to broaden our perspective on integration, and devise approaches in three novel directions of integration: modeling methods, data sets, and humans. This paper summarizes the latest advances, and discusses those directions and associated challenges in integration for cyber-physical systems.

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Integration Beyond Components and
Models: Directions and Challenges
Ivan Ruchkin
4th
Architecture-Centric Virtual Integration Workshop
WICSA/CompArch 2016
Venice, Italy
April 5, 2016

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Image credit: Ajinkya Bhave

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● Goal: Autonomy in the physical world

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● Goal: Autonomy in the physical world
● But: Heterogeneity of system elements

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● Goal: Autonomy in the physical world
● But: Heterogeneity of system elements
● But: Growing complexity and scale

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● Goal: Autonomy in the physical world
● But: Heterogeneity of system elements
● But: Growing complexity and scale
● Danger: interactions fail → systems fail

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Integration
Bringing together elements of a system
to make them operate cohesively.
Imagecredit:chevinfleet.com

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Integration
● What have we been doing?
– Integration for components; models.
Imagecredit:chevinfleet.com

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Integration
● What have we been doing?
– Integration for components; models.
● What is coming up?
– Integration for modeling methods; data; humans.
Imagecredit:chevinfleet.com

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Component IntegrationImagecredit:
technologynewhere.wordpress.com
Image credit: Ajinkya Bhave

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Component IntegrationImagecredit:
technologynewhere.wordpress.com
Image credit: Ajinkya Bhave

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Component IntegrationImagecredit:
technologynewhere.wordpress.com
Image credit: Ajinkya Bhave

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Component IntegrationImagecredit:
technologynewhere.wordpress.com
Image credit: Ajinkya Bhave

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Component IntegrationImagecredit:
technologynewhere.wordpress.com
Image credit: Ajinkya Bhave

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Component Integration
● Interface and composition
– E.g., FMI [1], automata interfaces [2]
[1] Blochwitz et al. Functional Mockup Interface 2.0: The Standard for Tool independent
Exchange of Simulation Models. 2012.
[2] Lampka et al. Component-based system design: analytic real-time interfaces for state-
based component implementations, STTT 2013.

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Component Integration
● Interface and composition
– E.g., FMI [1], automata interfaces [2]
– Tradeoff: universality vs. tractability
[1] Blochwitz et al. Functional Mockup Interface 2.0: The Standard for Tool independent
Exchange of Simulation Models. 2012.
[2] Lampka et al. Component-based system design: analytic real-time interfaces for state-
based component implementations, STTT 2013.

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Component Integration
● Interface and composition
– E.g., FMI [1], automata interfaces [2]
– Tradeoff: universality vs. tractability
● Compositional reasoning
– Contract-based design [3]
[1] Blochwitz et al. Functional Mockup Interface 2.0: The Standard for Tool independent
Exchange of Simulation Models. 2012.
[2] Lampka et al. Component-based system design: analytic real-time interfaces for state-
based component implementations, STTT 2013.
[3] Benveniste et al. Contracts for Systems Design: Theory, Research Report, 2015.

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Component Integration
● Interface and composition
– E.g., FMI [1], automata interfaces [2]
– Tradeoff: universality vs. tractability
● Compositional reasoning
– Contract-based design [3]
● Shortcoming: cross-cutting quality concerns
[1] Blochwitz et al. Functional Mockup Interface 2.0: The Standard for Tool independent
Exchange of Simulation Models. 2012.
[2] Lampka et al. Component-based system design: analytic real-time interfaces for state-
based component implementations, STTT 2013.
[3] Benveniste et al. Contracts for Systems Design: Theory, Research Report, 2015.

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Model Integration

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Model Integration

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Model Integration
1. Abstraction

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Model Integration
1. Abstraction
2. Relation

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Model Integration
1. Abstraction
2. Relation
Structural Behavioral
...

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● On the structural side:
– Metamodel composition [4]
– Architectural views [5]
Model Integration
[4] Passarini et al. Cyber-physical systems design: transition from functional to architectural models,
DAES 2015.
[5] Bhave et al. View Consistency in Architectures for Cyber-Physical Systems, ICCPS 2011.

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● On the structural side:
– Metamodel composition [4]
– Architectural views [5]
● On the behavioral side:
– Heterogeneous simulation [6]
– Behavior relations [7]
Model Integration
[4] Passarini et al. Cyber-physical systems design: transition from functional to architectural models,
DAES 2015.
[5] Bhave et al. View Consistency in Architectures for Cyber-Physical Systems, ICCPS 2011.
[6] Eker et al. Taming heterogeneity - the Ptolemy approach, Proc. of IEEE 20013.
[7] Rajhans et al. Supporting Heterogeneity in Cyber-Physical Systems Architectures, TAC 2014.

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● On the structural side:
– Metamodel composition [4]
– Architectural views [5]
● On the behavioral side:
– Heterogeneous simulation [6]
– Behavior relations [7]
● Shortcoming: fragility in the face of change
Model Integration
[4] Passarini et al. Cyber-physical systems design: transition from functional to architectural models,
DAES 2015.
[5] Bhave et al. View Consistency in Architectures for Cyber-Physical Systems, ICCPS 2011.
[6] Eker et al. Taming heterogeneity - the Ptolemy approach, Proc. of IEEE 20013.
[7] Rajhans et al. Supporting Heterogeneity in Cyber-Physical Systems Architectures, TAC 2014.

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Integration
● What have we been doing?
– Integration for components; models.
● What is coming up?
– Integration for modeling methods; data; humans.
Imagecredit:chevinfleet.com

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Modeling Method Integration

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Modeling Method Integration

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Modeling Method Integration
Focus: analysis/transformation procedures

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Modeling Method Integration
● Techniques:
– Dependency management [8]
[8] A. Qamar. Model and Dependency Management in Mechatronic Design, PhD Thesis, KTH 2013.

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Modeling Method Integration
● Techniques:
– Dependency management [8]
– Assumption verification [9]
[8] A. Qamar. Model and Dependency Management in Mechatronic Design, PhD Thesis, KTH 2013.
[9] Ruchkin et al. Contract-based Integration of Cyber-physical Analyses, EMSOFT 2014.

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Modeling Method Integration
● Techniques:
– Dependency management [8]
– Assumption verification [9]
● How can evolution of sets of heterogeneous
CPS models be systematically supported?
[8] A. Qamar. Model and Dependency Management in Mechatronic Design, PhD Thesis, KTH 2013.
[9] Ruchkin et al. Contract-based Integration of Cyber-physical Analyses, EMSOFT 2014.

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Modeling Method Integration
● Techniques:
– Dependency management [8]
– Assumption verification [9]
● How can evolution of sets of heterogeneous
CPS models be systematically supported?
● How can tools, processes, and methods for
CPS modeling be integrated?
[8] A. Qamar. Model and Dependency Management in Mechatronic Design, PhD Thesis, KTH 2013.
[9] Ruchkin et al. Contract-based Integration of Cyber-physical Analyses, EMSOFT 2014.

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Data Integration

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Data Integration
Imagecredit:DeshengZhang

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Data Integration
Focus: heterogeneous datasets
from CPS elements
Imagecredit:DeshengZhang

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Data Integration
● How can data incompleteness in CPS design
be detected and compensated for?

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Data Integration
● How can data incompleteness in CPS design
be detected and compensated for?
● How can model-based and data-centric
approaches to system design be (non-trivially)
synergized?

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Integration with Humans
● Humans as external agents
– “Human-in-the-loop”

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Integration with Humans
● Humans as external agents
– “Human-in-the-loop”
Imagecredit:historiaviation.com

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Integration with Humans
● Humans as external agents
– “Human-in-the-loop”
● How can humans be given adequate
comprehension and control of complex
systems?

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Integration with Humans
● Humans as external agents
– “Human-in-the-loop”
● How can humans be given adequate
comprehension and control of complex
systems?
● How can competing theories of human
cognition be reconciled in practical human
models?

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Integration with Humans
● Humans as external agents
– “Human-in-the-loop”
● How can humans be given adequate
comprehension and control of complex
systems?
● How can competing theories of human
cognition be reconciled in practical human
models?
● How can contextual fragility of human models
be bridged?

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Integration with Humans
● Humans as engineers

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Integration with Humans
Computer Science Electrical Engineering
Mechanical Engineering
● Humans as engineers

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Integration with Humans
● Humans as engineers
● How do the inherent biases of each CPS
discipline affect design and development?

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Integration with Humans
● Humans as engineers
● How do the inherent biases of each CPS
discipline affect design and development?
● What are the shared concepts, conflicts, and
omissions at the boundaries of disciplines?

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Summary
● In CPS integration overcomes heterogeneity and complexity.
● Foundations of integration:
– Components
– Models
● Emerging directions of integration:
– Modeling methods
– Data
– Humans
● Takeaway: let's broaden the horizons of integration!