Cyber-Physical Systems:
Issues and Challenges
Rabi N. Mahapatra
Texas A&M University
(Adopted from NSF Workshops)
March 18, 2016
WECON 2011
1
Overview





March 18, 2016
What are Cyber-Physical Systems?
Emerging Context: Applications, technical &
Economic
Issues & Challenges
Application Specific Research Identification
Summary
WECON 2011
2
What are Cyber-Physical Systems?
 What are CPS?
– Are they desktop computers?
– Are these traditional, post-hoc embedded/real-time systems?
– Are these today’s sensor nets?
Ans: None of the above!
• Some defining characteristics:
– Cyber capability in every physical component
– Networked at multiple and extreme scales
– Complex at multiple temporal and spatial scales
– Dynamically reorganizing/reconfiguring
– High degrees of automation, control loops must close at all
scales
– Unconventional computational and physical substrates (Bio?
Nano?)
– Operation must be dependable, certified in some cases
March 18, 2016
WECON 2011
3
Economic Context:
US & EU Competitiveness

American Competitiveness Initiative announced:
http://www.whitehouse.gov/stateoftheunion/2006/aci/

EU Framework Programme 7, European Research
Council, and related actions
• ARTEMIS
– Backbone of European Research Area for Embedded Systems,
http://www.artemis-office.org/
• Strategic Research Agenda (SRA)
• Joint Technology Initiative (JTI)
• Embedded systems education and curriculum
– “High-Level Group”
• CEOs: ABB, Airbus, Nokia, Parades, British Telecom, COMAU, Philips,
Bosch, Continental Teves, Daimler/Chrysler, ST Microelectronics,
Symbian, Ericsson, Finmecanicca, Telenor, Thales, IMEC, Infineon
• Universities and national research labs: TU Vienna, CNRS/Verimag
– Joint public and private funding
March 18, 2016
WECON 2011
4
Example: Health Care and Medicine
National Health Information Network, Electronic Patient Record
initiative
– Medical records at any point of service
– Hospital, ICU, …, EMT?
• Home care: monitoring and control
– Pulse oximeters (oxygen saturation), blood glucose
monitors, infusion pumps (insulin), accelerometers
(falling, immobility), wearable networks (gait
analysis), …
• Operating Room of the Future (Goldman)
– Closed loop monitoring and control; multiple
treatment stations, plug and play devices; robotic
microsurgery (remotely guided?)
– System coordination challenge
• Progress in bioinformatics: gene, protein
expression; systems biology; disease dynamics,
control mechanisms

Images thanks to Dr. Julian Goldman, Dr. Fred Pearce
March 18, 2016
WECON 2011
5
Example: Electric Power Grid

Current picture:
– Equipment protection devices trip
locally, reactively
– Cascading failure: August (US/Canada)
and October (Europe), 2003
 Better future?
– Real-time cooperative control of
protection devices
– Ubiquitous green technologies
– Issue: standard operational control concerns exhibit wide-area
characteristics (bulk power stability and quality, flow control,
fault isolation)
– Context: market (timing?) behavior, power routing
transactions, regulation
March 18, 2016
WECON 2011
6
Application Example
Example of a CPS concept (fiction)
Concept : Personal Assistant
Weebo – from the movie ‘Flubber’
Flubber © Disney Motion Pictures 1997
March 18, 2016
WECON 2011
7
Application Example
Fiction becomes reality
NASA – Personal Satellite Assistant (concept)
•Will help astronauts in space
•Will have built-in propulsion
and navigation
•Can go to difficult to reach
places
Personal Satellite Assistant © NASA Ames Research Center
March 18, 2016
WECON 2011
8
Personal Satellite Assistant
•The PSA is about the size of a softball
•Has sensors for measuring gases,
temperature, and air pressure.
•PSA can video conference &
communicate with electronic support
devices such as computer servers,
avionics systems, and wireless LAN
bridges.
•PSA is a robotic assistant for
astronauts working in space.
Prototype
Artist’s concept of a PSA
assisting an astronaut
March 18, 2016
WECON 2011
Images © NASA Ames Research Center
9
Defining Cyber-Physical Systems:

A cyber-physical system integrates
computing, communication and storage
capabilities with the monitoring and/or
control of entities in the physical world

dependably, safely, securely, efficiently and in
real-time.
Seek scientific foundations and technologies to
integrate cyber-concepts with the dynamics of
physical and engineered systems.
March 18, 2016
WECON 2011
10
Long-Term Goal

Transform how we interact with the
physical world just like the internet
transformed how we interact with one
another.

Transcend space and yet control the physical
environment
Produce significant impact on society and
national competitiveness.
March 18, 2016
WECON 2011
11
Industry Sectors To Benefit






Automobiles
Industrial Automation
Energy
Defense and Space
Intelligent Homes and
Health/Medical Equipment
Other Sectors to benefit:
• Telecommunications
• Consumer Electronics
March 18, 2016
WECON 2011
12
Possible Cyber-Physical Systems









Medical devices and health management networks
Tele-physical operations
Vehicular networks and smart highways
Physical infrastructure monitoring and control
Electricity generation and distribution
Robotic manufacturing
Aviation and airspace management
Defense and aerospace systems
…
In general, any “X by wire(less)” where X is
anything that is physical in nature.
March 18, 2016
WECON 2011
13
Issues & Challenges
March 18, 2016
WECON 2011
14
Fundamental Challenges

From a synthesis perspective



Architecture
Requirements and their management
Formalization of the constraints imposed by the
Physical layer (physical – cyber interface and
boundary)
Grand Challenge:
Compositional approach to Cyber-Physical
Systems Design and Synthesis.
March 18, 2016
WECON 2011
15
From IT Abstractions to
“Hardware/Software”
From CAD schematics to chips
From DNA
‘programs’ to
living organisms
ISR-SEIL, Copyright © 2006
March 18, 2016
WECON 2011
16
From IT Abstractions to “HW/SW”
From algorithms and schematics to radios
Embedded systems design tools
Picoradio
INS
UAV Controller
R-50 Hovering
GPS Antenna
No difference between HW and SW
HW/SW co-design,, software radios
GPS Card
ISR-SEIL, Copyright © 2006
March 18, 2016
WECON 2011
17
A Glimpse into the Future
Autonomic wireless networks, self-organizing collaborative robotics,
self assembled systems and materials

Computing over new Physical domains
(Quantum, organic, biological)
•from abacus to qubits
• entanglement
• nuclear spin, electron spin
• photon polarization, ion trap

As dimensions get
smaller what is cyber
and what is physical
gets fuzzier
•Communicating minds
From material layer
controlled by cyber layer
to “programmable matter”
•Swarm intelligence
March 18, 2016
True convergence of
Control, communication
computing
WECON 2011
ISR-SEIL, Copyright © 2006
18
Areas of Challenge







March 18, 2016
Communication between the components
Data Storage & Retrieval
Data Security
Scalability
Management of the CPS devices
User Interfaces
Safety
WECON 2011
19
Challenge > Communication
Communication


Large amounts of data transfer will be
required
Will need enhanced wireless protocols
which support

Low power consumption




March 18, 2016
(can power criteria be part of the protocol ? )
High Bandwidth
High Data Transfer Rates
Intelligent traffic management and routing.
WECON 2011
Image © davisdrive.wcpss.net
20
Challenge > Communication
Communication-Security




March 18, 2016
Will require robust security to protect the
data that is to be transferred.
Should be light on computational and
memory requirements.
Should be able to gracefully degrade in
case of attacks.
Can we have self-quarantining of
compromised sections/areas ?
WECON 2011
NSF Workshop, Austin, October 17,
212006
Challenge > Data Storage & Retrieval
Data Storage & Retrieval

Depending on application

Monitoring type application


Interactive application



March 18, 2016
low quantity on individual nodes
possibly huge amounts of data stored
Should adopt distributed storage
algorithms
Algorithm selection cannot be generic, will
be application specific.
WECON 2011
Image © NeoScale Systems
22Inc
Challenge > Scalability
Scalability


CPS will be a global, open & extensible
platform
Questions:



March 18, 2016
How do we describe, discuss, deduce the
invariants of such a global system ?
How do we model the expansion of such a
system ?
How will such a system scale to planetwide use and deployment ?
WECON 2011
23
Management of CPS

How do we deploy and control large scale
applications ?



Wireless networks that can perform selforganization.
Adaptive routing protocols for traffic control
and efficient routing.
Multiple smaller deployments that collaborate
into one large network .

(an Internet of CPS ?)
Image © www.niaid.nih.gov
March 18, 2016
WECON 2011
24
Safety of Cyber-Physical Systems
March 18, 2016
WECON 2011
25
Interactive Complexity

Two dimensions
− Coupling: Tight vs. Loose
• Delay and ordering tolerance,resource slack,
inherent buffering (vs. designed in)
− Interactions: Complex vs. Linear
• Degree of feedback, number of common mode
connections, limited system understanding, reliance
of human expertise, many control parameters
Systems with high interactive complexity
possess numerous hidden interactions
that can lead to systems accidents
− Nuclear Power Plants

− Chemical Plants
− Software Systems
System Accident: The halting of system
operations due to damage or failure of
multiple subsystems that arises from the
unanticipated interactions of multiple
failures

March 18, 2016
WECON 2011
26
Cyber Physical System Accidents

USS Yorktown
(http://www.slothmud.org/~hayward/mic_humor/nt_
navy.html )
− Suffered a systems failure when bad data was fed into its
computers during maneuvers off the coast of Cape Charles,
VA.
− The ship had to be towed into the Naval base at Norfolk,
VA., because a database overflow caused its propulsion
system to fail
− ”We are putting equipment in the engine room that we
cannot maintain and, when it fails, results in a critical
failure," DiGiorgio said. It took two days of pier-side
maintenance to fix the problem.
March 18, 2016
WECON 2011
27
Accident due to SW Bug
Ariane Five
(http://www.ima.umn.edu/~arnold/disasters/ariane5rep.html)
Ariane 5 reused a module developed for
Ariane 4, which assumed that the
horizontal velocity component would not
overflow a 16-bit variable.
− This was true for Ariane 4 but not for
Ariane 5, leading to self-destruction roughly
40 seconds after the launch.
− “The [Ariane 5] alignment function is
operative for 50 seconds after starting of
the Flight … This time sequence is based
on a requirement of Ariane 4 and is not
required for Ariane 5.” (Report by the
Inquiry Board)
March 18, 2016
WECON 2011
28
Interactive Complexity in Cyber Physical
Systems
Cyber Physical Systems Typically Have High Interactive Complexity
− Many tightly coupled system threads with hard deadlines
− Shared resources among mission critical and non-mission critical systems
− Give rise to numerous hidden dependencies, which then lead to unexpected
function, performance, or accidents
 Limited Design Time Support to Understand or Reduce Interactive
Complexity
− Existing analytical methods e.g. rate monotonic analysis, address individual
aspects but skilled practitioners are required to employ these techniques
• As a result we see limited application
− Simulations are typical hand written and are difficult to keep synchronized
with the design; or abstract away details that lead to hidden dependencies
 Present Cyber Physical Systems Rely on Human Ingenuity at Design Time
and Extensive System Testing to Manage Interactive Complexity
− As a result, we experience long and costly development efforts that are expected to
encounter system accidents.

March 18, 2016
WECON 2011
29
Application Research Initiative
March 18, 2016
WECON 2011
30
Application Specific Approaches

Cyber-Bio Interface

Critical Physical Infrastructure

Tele-Interaction

Smart Transportation

System Infrastructure
March 18, 2016
WECON 2011
31
Application Specific Approaches
Cyber Bio Interface
The four questions for cyber-bio systems
1.
Can biological systems operationalize certain aspects of cyber
systems so that we can understand and design advanced
biological systems?
2.
Can biological systems operationalize certain aspects of cyber
systems so that we can understand and design advanced
cyber systems?
3.
Can cyber systems operationalize certain aspects of biological
systems so that we can understand and design advanced
biological systems?
4.
Can cyber systems operationalize certain aspects of biological
systems so that we can understand and design advanced cyber
systems?
Harvey Rubin, MD, PhD University of Pennsylvania, NSF, Austin, October 17, 2006
March 18, 2016
WECON 2011
32
Application Specific Approaches
Cyber Bio Interface
1.
Can biological systems operationalize certain aspects of
cyber systems so that we can understand and design
advanced biological systems?
Answer : YES

Up to the level of tissues and cultures, this is
predominantly in the world of synthetic biology.
1918 Flu Epidemic : Complete genome sequenced in 2005
March 18, 2016
Harvey Rubin,
MD, PhD University of Pennsylvania, NSF, Austin, October 17,
WECON
2011
332006
Application Specific Approaches
Cyber Bio Interface
2. Can biological systems operationalize certain aspects of
cyber systems so that we can understand and design
advanced cyber systems?
Answer : No
While DNA computation has been proved possible, time for the
‘gate’ to operate has been in the order of several seconds
Harvey Rubin, MD, PhD University of Pennsylvania, NSF, Austin, October 17, 2006
March 18, 2016
WECON 2011
34
Application Specific Approaches
Cyber Bio Interface

Physical Limitations of DNA Computing

March 18, 2016
Hamiltonian path problem
 25 nodes…..
 1 kilogram of DNA needed
 70 nodes…..
 1000 kilograms of DNA needed !
Harvey Rubin,
MD, PhD University of Pennsylvania, NSF, Austin, October 17,
WECON
2011
352006
Application Specific Approaches
Cyber Bio Interface
3.
Can cyber systems operationalize certain aspects of
biological systems so that we can understand and design
advanced biological systems?
Answer: Yes
Nano-bio

Medical devices

Lab on a chip

NSF workshop on high confidence medical
devices and software systems last year

Subject of Tele-Physical services and
applications working group at NSF
Workshop
> $3 billion invested already !

2007 NSTI Nanotechnology Conference and Trade Show – May 2007 - Santa Clara
March 18, 2016
Harvey Rubin,
MD, PhD, University of Pennsylvania, NSF, Austin, October 17,
WECON
2011
362006
Application Specific Approaches
Cyber Bio Interface
4. Can cyber systems operationalize certain aspects of biological
systems so that we can understand and design advanced
cyber systems?

Answer : Yes !
Has been happening all the time:
Harvey Rubin, MD, PhD, University of Pennsylvania, NSF, Austin, October 17, 2006
March 18, 2016
WECON 2011
37
Application Specific Approaches
Cyber Bio Interface

examples abound
(from molecular level to societal level)

Persistence in bacteria


Cellular metabolism : metabolic flux models


supply chain
Swarm behavior



hedge strategy against attack
Autonomous mobile robots
Inverse problem
Markets


Data aggregation
Event prediction
Harvey Rubin, MD, PhD, University of Pennsylvania, NSF, Austin, October 17, 2006
March 18, 2016
WECON 2011
38
Critical Physical Infrastructure

What is Critical Physical Infrastructure?

March 18, 2016
CPS Infrastructure: Interconnected systems
with seamless interaction between computing
and physical systems.
WECON 2011
39
Critical Physical Infrastructure
Current Challenges

What to do with data collected by the CPS - for e.g. (oil

Develop large scale models of the physical world
pipeline inspections)
 Translate / Interpret data and arrive at a decision
 Communicate with the people in charge.





March 18, 2016
Being done in SCADA for prediction
SCADA - Supervisory Control And Data Acquisition :
 (called Human Machine Interface in Europe)
Large Scale Distributed Measurement (and Control) System
We need data on abnormal conditions
 CPS are subject to massive (cascading) failures.
 Power Grid, Air Traffic, Automotive, Data Centers
How do we handle unpredictable component interactions ?
WECON 2011
40
Tele-Interaction

Remote/Distributed = Tele



March 18, 2016
Perception
Action
Interaction
WECON 2011
NSF Workshop, Austin, October 17,
412006
Scenarios Tele-Interaction Application

First responder applications


Tele-health, tele-services for aging population
(assisted living)




March 18, 2016
Collaborative dancing
Physiotherapy between a doctor and patient
Training environment for training medical personal for
tele-surgery


Dangerous environments, under water exploration,
fire fighting
Tele-immersion inside of the body
Network of robots and sensors that work in a cyber-physical
spaces with a remote human in the loop to accomplish
dangerous, unpleasant, or super-human activities
Factory automation and reconfiguration
WECON 2011
NSF Workshop, Austin, October 17,
422006
Tele Interaction - Unmet Needs







March 18, 2016
Latency-sensitive Internet
Display technology and the overall I/O technology
Haptic technology needs higher time resolution,
many sensors and display to emulate whole hand
sensing and actuation
Interactive human-machine interfaces are limited
Managing Complexity
Networked self-organization
Trust, Security and self-certifying software
WECON 2011
43
Tele-Interaction Challenges






March 18, 2016
How do we achieve
 being in remote space
 feeling in remote space
 effecting remote space
Synchronization in multi-modal environments;
Trust (reliability, safety, privacy, …)
Robust and fault tolerant systems
Achievement of autonomy and semi-autonomy
Reusable user interfaces
WECON 2011
44
Smart Transportation
Challenges

Basic Goal : move people and goods





“Smart” ?


March 18, 2016
Safely and reliably
Efficiently (min resources, no environmental damage)
Quickly
Desirably (passenger’s experience should be fun)
Use CPS to improve / facilitate all of the above
Use the transportation system to provide traffic, GIS,
terrain data
WECON 2011
NSF Workshop, Austin, October 17,
452006
CPS Enabled Automobile Trend
Goals
– Enhance safety of vehicle and occupants during various driving
maneuvers; avoid crashes
– Enhance convenience of driver of the vehicle
• Trend is shift from warning-only or information-only systems (e.g.,
collision warning systems) to systems that actively control acceleration
and braking (longitudinal motion) and steering (lateral motion), leading
to semi-autonomous and eventually fully autonomous vehicle
operation
• Examples:
– Forward collision warning
– Adaptive Cruise Control (ACC) + extensions
– Curve speed control
– Side blind zone alert
– Lane change assist
– Lane keeping / lane centering control
– Cross traffic collision avoidance
– Parking assist
March 18, 2016
WECON 2011
46
Research Needs for Auto Industries
360°sensing via vision, radar, sonar, and sensor fusion for higher
level
situational awareness
• Robust requirements: how should the vehicle behave in anticipation of
every possible real-world driving scenario

• Driver experience, skill level, and mental state (e.g., drowsiness,
inattentiveness)
• Vehicle state of health / maintenance / repair
• External environmental factors (weather conditions, road conditions,
traffic conditions)
• Learning, adaptable, reconfigurable run-time systems
• Fault tolerant architectures
– Hardware and Software fault tolerance (USCAR project on run-time
architecture)
• Distributed diagnosis/prognosis
• Human Vehicle Interface
– Sensing and learning the driver’s skills, habits, and current condition
(attention, drowsiness, impairment)
– Driver workload management
March 18, 2016
WECON 2011
47
System Infrastructure

Problem Statement:

Coupling interface between computers and the
physical world.



Self Configurability of systems and system
parameters within requirements


March 18, 2016
Methods and models for validation
Co-development
Self description capable , self aware systems
Education
WECON 2011
48
System Infrastructure -Challenges


Dealing with time, distributed architecture,
space, scale
Dealing with the hybrid nature of CPS



March 18, 2016
Security ?
Adaptive OS / Self regeneration capability
Engineering Education Issues
WECON 2011
NSF Workshop, Austin, October 17,
492006
Summary


CPS is the hype of next decades!
Involves multi-disciplinary research




March 18, 2016
High confidence SW
CPS has the potential to change the way
people interact with their surroundings
applications in the future for CPS are
limited only by human imagination
Affordability and ease of use will drive
adoption
WECON 2011
50