Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Towards Dynamic Dependable Open Cyber-Physical Systems
András PatariczaBudapest University of Technology and Economics
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Contributors Dr. Tamás DABÓCZY Dr. Tamás KOVÁCSHÁZY Prof. Dr. Dániel VARRÓ Dr. István MAJZIK Dr. István RÁTH Dr. Ákos HORVÁTH Imre KOCSIS Ábel HEGEDŰS Ágnes SALÁNKI and many others
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"Cyber-Physical Systems" European Union,
European Social Fund (TÁMOP-4.2.2.C-11/1/KONV-2012-0001), 2012-2014
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
THE NEW ERA: DYNAMIC CPS (?)
Unlimited intelligence by the synergy of intelligence in the cyber
space and ES interfacing
the physical world
|Institut nn | Prof. nn
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WEBCyber
CLOUDComp.
CPS
ESPhysical
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Motivation
Intention Reality: record flood
A lot of e-mails: − Is it safe to come to Budapest?
Fortunately: no request for“Life west under your conference seat”
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Solution
Reusable sensorsMultiple, on-demand algorithms
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
ExampleCameras on riverside Different applications
concurrently using the same primary information
Tasks can change according to time/season/requirements
● Identification of ships● Monitoring the break-up of ice● Monitoring the water level● Monitoring the speed of flood● Pollution check● Supervision of hostile entrance to the ship
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
The design triangle
WEBCyber
CLOUDComp.
CPS
ESPhysical
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Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Dynamic cyber-physical systemsCyber world
Physical world
Problem
Solutionscheme
Deployment
Service
Solutionpattern
Componentservice offering
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
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Critical CPS design and challenges
Transformation
Design modell
Communicationsynthesis
Behavioral model
Implementation& testing
Hardware synthesis
Software synthesis
Simulation
Parameterization
Verification
Partitioning
Optimization
Scheduling
Specification Completenessconsistency
Completenessconsistency
Fault modelling, testing
Fault modelling, testing
Measurement and extraction
Measurement and extraction
Benchmarking, data processingBenchmarking, data processing
Complexity?Complexity?Mobile, ad-hoc,
large scaleMobile, ad-hoc,
large scale
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
The change in ES design
WEBCyber
CLOUDComp.
CPS
ESPhysical
9
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
ES paradigm shift
Traditional
Industrialized• Best component technologies• Standardized components• Automated system design
Component integration based system designMDD/Service based integration
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Service Oriented Approach
SOAEmbedded systems
provide services Information of
− sensors− Internet
High level information derived
Actuation possibility (limited)
Services in a database
MDDUpon a new task: solution based on
− design patterns and − available resources
New solution deployed no interference with
the already running ones
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Case study: supervising a server roomObservations temperature humidity state of doors/windows monitoring the power consumption weather
(temp./humidity) temperature of outflow air of air conditioning state of server computers/switches (video
based)
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FIRST
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
The design triangle
WEBCyber
CLOUDComp.
CPS
ESPhysical
13
Sensors• Temperature• Humidity• Web camera• Power meter• Microswitches
windows/doorsImage processing• JPEG stream• Available via
the Internet • ThresholdVirtualization for sensor drivers
Weather• status• forecast
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Dynamic composition of cyber-physical systems
WEBCyber
CLOUD
Comp.
CPS
ESPhysical
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Composability through abstraction Finding a conceptual domain where devices
are homogeneous− Possibly the lowest level of such domains
Abstraction of computing capabilities− Virtualization
Abstraction of physical capabilities− Sensor virtualization (SOS), − Feature discovery
Abstraction of communication capabilities− Self-describing communication interface (SOS)
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Sensor Observation Service (SOS) Abstracts sensor data and
communication− Self-describing sensor information
database− Stores sensor data
with geographic relevance− Efficient data queries
● temporal or spatial filters
Members of the CPS− direct communication with the SOS
offering
procedure 1
feature of interest
procedure 2
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
W3C Semantic Sensor Network ontology Formal ontology : Capabilities of sensors
− system, deployment, sensing device, process− observed phenomenon (e.g. wind)
● sensor type (e.g. ultrasonic wind sensor)
● property (e.g. wind direction)
● meaning (e.g. blows from direction)
● unit of measure (e.g. radian)
− operating range (e.g. temperature, humidity...)
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Architecture
Application monitoring
SISROOWL ontology
Application designer
User applicatio
ns
RDF triplestoreConfiguration planner
Plan execution
install/uninstallstart/stop
SOS -> OWLtransformation
Sensor metadataand observations
Node & applicationperformance data
Embedded system
Sensor search and monitoring
host OS (Linux)virtualizationapplications performance
riporting
Register application
Sensor / actuator
Store observation
Sensor Observation Service
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Core of run-time design
WEBCyber
CLOUDComp.
CPS
ESPhysical
19
Changedriven,
Incremental MDD
Challenge:Detect changes• in system state• in environmentAbstractionsDesign spaceexploration
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Dynamic reconfiguration of resources20 / 16
User applications describe observational and processing constraints
Design space exploration
New system state
Performance monitoringDeployment
System state monitoring
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
route: Route sp: SwitchPosition
switch: Switchsensor: Sensor
switchPosition
switchsensor
routeDefinition
Incremental Graph Pattern Matching
Main idea: More space to less time− Cache matches of patterns− Instantly retrieve match (if valid)− Update caches upon model changes− Notify about relevant changes
Approaches: − TREAT, LEAPS, RETE, …− Tools: VIATRA, GROOVE, MoTE,
TCore
straight
left
route sp switch sensorr1 sp1 sw1
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
• Declarative graphquery language• Transitive closure,
Negative cond., etc.• Compositional,
reusable
• Declarative graphquery language• Transitive closure,
Negative cond., etc.• Compositional,
reusable
Definition
• Incremental evaluation• Cache result set• Maintain incrementally
upon model change
• Incremental evaluation• Cache result set• Maintain incrementally
upon model change
Execution
• Derived features,• On-the-fly validation• View generation,
Notifications, Softlinks, Databinding,
• Derived features,• On-the-fly validation• View generation,
Notifications, Softlinks, Databinding,
Features
EMF-IncQuery: An Open Source Eclipse Project
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
IncQUERy-D: Distributed Incremental Model Queries
Decouple and separately distribute Storage, Indexer and Query
Distributed Model Storage
• Adaptable todifferent back-end storages
• Agnostic tograph repres.
• TripleStores(RDF), EMF,Property graph
Model Access Adapter
• Surrogate keyto identifydistibutedelements
• Graph manip. API
• Changenotifications
DistributedIndexer
• Type-instanceindices, etc.
• Stored onmultipleservers
• Protectsexceedingmemory limits
DistributedQuery Evaluator
• DistributedRETE network
• Distributedterminationprotocol
• Constructedand deployedby coordinatornode
yhttp://eclipse.org/incquery
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Design Space Exploration
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Design Space Exploration
Design Alternative 1
Design Alternative 2
Design Alternative 3
Design Alternative 4
Objectives
Global Constraints
Initial Design
Solvers• CLP solvers (Choco)• model finders (Alloy)• meta-heuristics + multi-objective optimization
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Self-* properties – dynamic challenges and solutions
WEBCyber
CLOUDComp.
CPS
ESPhysical
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Self-configuration
Self-healing
Self-protection
Self-optimization
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Appearance of cloud-based semantic services “Drag-and-drop”
application prototyping
Uniformization− Meta-algorithms− Data
● COMPUTED● SENSED
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IBM Internet of Things (IoT) Foundation
Wolfram Connected Devices Project
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
• Data protection• Detection ,• Identification , • Reaction
• Effectivity of resource use• Load balancing• Workload tuning
• FT• Detection• Diagnostics• Compensation
• Reactiveness• Adaptation to
the dynamically changing enviroment
Self-configuration Self-healing
Self-protection
Self-optimization
Self-* properties – dynamic challenges•Mobility•Evolution: • Problem• Requirement• Priorities
•Mobility•Evolution: • Problem• Requirement• Priorities
•Evolution: •Resource set•Capability•Capacity•Workload
•Evolution: •Resource set•Capability•Capacity•Workload
•Evolution: • Fault/failure
modes
•Evolution: • Fault/failure
modes
•Evolution: • Requirements• Threads
•Evolution: • Requirements• Threads
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Opportunities and threats in the CPS
WEBCyber
CLOUDComp.
CPS
ESPhysical
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Aaas –algorithm as a service- “Meta-algorithms’ - -Self-checking ABFT- External validator
Redundancy• Multitude of sensorsAlgorithmic failover/n-version
Cheap redundancyVirtualized network (SDN)
Budapest University of Technology and Economics
Fault-Tolerant Systems Research Group
Summary Virtualization is a means for
− Resource sharing− Dynamic task allocation− Redundancy based fault tolerance
Abstraction− “n-version” programming with failover
50 years of FT knowledge has to be revisited MDD
− Opprtunity for creating self-* systems
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