Sound Invariant Generation for Continuous and Hybrid Systems
Lead PI:
Andre Platzer
Abstract
This project considers the pragmatic challenge of broadening the reach and general accessibility of cyber-physical system (CPS) analysis. It capitalizes on logical foundations for cyber-physical systems to study automated analysis for CPS without sacrificing correctness of the analysis results. While the complexities of CPSs can be quite demanding, there is a considerable pragmatic difference between rigorous reasoning techniques that are available to verification experts compared to techniques that provide a vast amount of automation support to become more accessible for novices and more productive for experts. This project focuses on finding invariants, which convey crucial insights about quantities or relationships, such as minimum safety distances, that do not change while the CPS drives or flies. Cyber-physical systems such as self-driving cars, advanced computerized car safety technology, and drones have considerable potential to change the world for the better. Their designs face intensive safety requirements, however, and feature increasingly complex behaviors. The advanced but correct automation of CPS analysis technology developed in this project is crucial to broaden the reach of trustworthy verification and validation results. In the long run, there is a chance that this technology will fundamentally change the way that CPS are engineered by enabling CPS engineers to have increasingly comprehensive safety analysis tools at their fingertips. As a demonstration with considerable impact potential, this project studies safe control functionalities for quadrotors. Quadcopters are a popular choice for realizing many applications, but their safety is a nontrivial challenge. Not every company or grass-roots effort will have the capacity to conduct a full verification and validation effort. That is why a set of baseline functionalities that have been preverified are expected to be a helpful basis for such designs. The results of this project, including CPS models, controllers, proofs, and tools, will be made available on the KeYmaera X web page: http://keymaeraX.org/
Andre Platzer

André Platzer is a Professor of Computer Science at Carnegie Mellon University, Pittsburgh, PA, USA. He develops the Logical Foundations of Cyber-Physical Systems (NSF CAREER). In his research, André Platzer works on logic-based verification and validation techniques for various forms of cyber-physical systems, including hybrid systems, distributed hybrid systems, and stochastic hybrid systems. He developed differential dynamic logic and differential invariants and leads the development of the CPS verification tool KeYmaera X.

André Platzer received an ACM Doctoral Dissertation Honorable Mention Award, an NSF CAREER Award, and was named one of the Brilliant 10 Young Scientists by the Popular Science magazine 2009 and one of the AI's 10 to Watch 2010 by the IEEE Intelligent Systems Magazine.

Performance Period: 09/01/2017 - 08/31/2020
Institution: Carnegie-Mellon University
Sponsor: National Science Foundation
Award Number: 1739629
CPS: Breakthrough: Design of Network Dynamics for Strategic Team-Competition
Lead PI:
Carolyn Beck
Abstract
Over the past decade there has been a growing awareness and interest in large networked systems such as those presented by power (smart-grid), communication, biological, social and sensor networks. A large body of research focused on networked systems has resulted where the primary goal has been the design of strategies by which individual agents in a network cooperate to achieve coordinated goals. Less studied are competitive-strategic scenarios where agents may be competing while trying to achieve their objectives, or may be competing in teams using local communications for local coordination purposes. This project considers the competitive-strategic domain for two opposing teams, motivated by applications that can abstractly be viewed as a competition between a large collection of autonomous agents, and an adversarial agent or team of adversaries. A primary example is the problem of controlling a large wind farm composed of numerous turbines: each rotating blade creates a downstream wake and every turbine faces the problem of setting an appropriate rotation speed under complex aerodynamic interactions. The cooperative control problem is to determine rotation speeds for the individual turbines that maximize the total collective energy extracted from the wind, under wake effects from neighboring turbines and difficult-to-predict variations in wind speeds and directions. In this example, the Principal Investigators propose to address a generalization of the problem where the turbines are viewed as competing against nature, which continually and adversarial changes the wind speed at each turbine. Ongoing with the analytical and applications-oriented research efforts will be the development of educational programs with interdisciplinary activities in optimization, mathematical systems theory, game theory and clustering algorithms. Both graduate and undergraduate students will be involved, with an emphasis on attracting students from underrepresented groups to participate in the research activities throughout the duration of the project.
Performance Period: 02/15/2016 - 01/31/2019
Institution: University of Illinois at Urbana-Champaign
Sponsor: National Science Foundation
Award Number: 1544953
CPS: Synergy: Sensor Network-Based Lower-Limb Prosthetic Optimization and Control
Lead PI:
Array Array
Abstract
More than one million people including many wounded warfighters from recent military missions are living with lower-limb amputation in the United States. This project will design wearable body area sensor systems for real-time measurement of amputee's energy expenditure and will develop computer algorithms for automatic lower-limb prosthesis optimization. The developed technology will offer a practical tool for the optimal prosthetic tuning that may maximally reduce amputee's energy expenditure during walking. Further, this project will develop user-control technology to support user's volitional control of lower-limb prostheses. The developed volitional control technology will allow the prosthesis to be adaptive to altered environments and situations such that amputees can walk as using their own biological limbs. An optimized prosthesis with user-control capability will increase equal force distribution on the intact and prosthetic limbs and decrease the risk of damage to the intact limb from the musculoskeletal imbalance or pathologies. Maintenance of health in these areas is essential for the amputee's quality of life and well-being. Student participation is supported. This research will advance Cyber-Physical Systems (CPS) science and engineering through the integration of sensor and computational technologies for the optimization and control of physical systems. This project will design body area sensor network systems which integrate spatiotemporal information from electromyography (EMG), electroencephalography (EEG) and inertia measurement unit (IMU) sensors, providing quantitative, real-time measurements of the user's physical load and mental effort for personalized prosthesis optimization. This project will design machine learning technology-based, automatic prosthesis parameter optimization technology to support in-home prosthesis optimization by users themselves. This project will also develop an EEG-based, embedded computing-supported volitional control technology to support user?s volitional control of a prosthesis in real-time by their thoughts to cope with altered situations and environments. The technical advances from this project will provide wearable and wireless body area sensing solutions for broader applications in healthcare and human-CPS interaction applications. The explored computational methods will be broadly applicable for real-time, automatic target recognition from spatiotemporal, multivariate data in CPS-related communication and control applications. This synergic project will be implemented under multidisciplinary team collaboration among computer scientists and engineers, clinicians and prosthetic industry engineers. This project will also provide interdisciplinary, CPS relevant training for both undergraduate and graduate students by integrating computational methods with sensor network, embedded processors, human physical and mental activity recognition, and prosthetic control.
Performance Period: 05/16/2015 - 11/30/2019
Institution: Florida International University
Sponsor: National Science Foundation
Award Number: 1552163
CPS/Synergy/Collaborative Research: Safe and Efficient Cyber-Physical Operation System for Construction Equipment
Lead PI:
Mani Golparvar-Fard
Co-PI:
Abstract
Equipment operation represents one of the most dangerous tasks on a construction sites and accidents related to such operation often result in death and property damage on the construction site and the surrounding area. Such accidents can also cause considerable delays and disruption, and negatively impact the efficiency of operations. This award will conduct research to improve the safety and efficiency of cranes by integrating advances in robotics, computer vision, and construction management. It will create tools for quick and easy planning of crane operations and incorporate them into a safe and efficient system that can monitor a crane's environment and provide control feedback to the crane and the operator. Resulting gains in safety and efficiency will reduce fatal and non-fatal crane accidents. Partnerships with industry will also ensure that these advances have a positive impact on construction practice, and can be extended broadly to smart infrastructure, intelligent manufacturing, surveillance, traffic monitoring, and other application areas. The research will involve undergraduates and includes outreach to K-12 students. The work is driven by the hypothesis that the monitoring and control of cranes can be performed autonomously using robotics and computer vision algorithms, and that detailed and continuous monitoring and control feedback can lead to improved planning and simulation of equipment operations. It will particularly focus on developing methods for (a) planning construction operations while accounting for safety hazards through simulation; (b) estimating and providing analytics on the state of the equipment; (c) monitoring equipment surrounding the crane operating environment, including detection of safety hazards, and proximity analysis to dynamic resources including materials, equipment, and workers; (d) controlling crane stability in real-time; and (e) providing feedback to the user and equipment operators in a "transparent cockpit" using visual and haptic cues. It will address the underlying research challenges by improving the efficiency and reliability of planning through failure effects analysis and creating methods for contact state estimation and equilibrium analysis; improving monitoring through model-driven and real-time 3D reconstruction techniques, context-driven object recognition, and forecasting motion trajectories of objects; enhancing reliability of control through dynamic crane models, measures of instability, and algorithms for finding optimal controls; and, finally, improving efficiency of feedback loops through methods for providing visual and haptic cues.
Performance Period: 01/01/2016 - 12/31/2019
Institution: University of Illinois at Urbana-Champaign
Sponsor: National Science Foundation
Award Number: 1544999
CPS: Synergy: Collaborative Research: Autonomy Protocols: From Human Behavioral Modeling to Correct-By-Construction, Scalable Control
Lead PI:
Behcet Acikmese
Abstract
Computer systems are increasingly coming to be relied upon to augment or replace human operators in controlling mechanical devices in contexts such as transportation systems, chemical plants, and medical devices, where safety and correctness are critical. A central problem is how to verify that such partially automated or fully autonomous cyber-physical systems (CPS) are worthy of our trust. One promising approach involves synthesis of the computer implementation codes from formal specifications, by software tools. This project contributes to this "correct-by-construction" approach, by developing scalable, automated methods for the synthesis of control protocols with provable correctness guarantees, based on insights from models of human behavior. It targets: (i) the gap between the capabilities of today's hardly autonomous, unmanned systems and the levels of capability at which they can make an impact on our use of monetary, labor, and time resources; and (ii) the lack of computational, automated, scalable tools suitable for the specification, synthesis and verification of such autonomous systems. The research is based on study of modular reinforcement learning-based models of human behavior derived through experiments designed to elicit information on how humans control complex interactive systems in dynamic environments, including automobile driving. Architectural insights and stochastic models from this study are incorporated with a specification language based on linear temporal logic, to guide the synthesis of adaptive autonomous controllers. Motion planning and other dynamic decision-making are by algorithms based on computational engines that represent the underlying physics, with provision for run-time adaptation to account for changing operational and environmental conditions. Tools implementing this methodology are validated through experimentation in a virtual testing facility in the context of autonomous driving in urban environments and multi-vehicle autonomous navigation of micro-air vehicles in dynamic environments. Education and outreach activities include involvement of undergraduate and graduate students in the research, integration of the research into courses, demonstrations for K-12 students, and recruitment of research participants from under-represented demographic groups. Data, code, and teaching materials developed by the project are disseminated publicly on the Web.
Performance Period: 01/01/2016 - 09/30/2018
Institution: University of Washington
Sponsor: National Science Foundation
Award Number: 1624328
CPS: Synergy: Collaborative Research: Support for Security and Safety of Programmable IoT Systems
Lead PI:
Atul Prakash
Abstract
This work examines how to get safety and security in Internet of Things (IoT) systems where multiple devices (things), each designed in isolation from others, are brought together to form a networked system, controlled via one or more software applications ("apps"). "Things" in an IoT environment can include simple devices such as switches, lightbulbs, smart locks, thermostats, and safety alarms as well as complex systems such as appliances, smartphones, and cars. Software IoT "apps" can monitor and control multiple devices in homes, cars, cities, and businesses, providing significant benefits such as energy efficiency, security, safety, and user convenience. Unfortunately, programmable IoT systems also introduce new risks, including enabling remote control by hackers of devices in smart homes, cars, and cities, via buggy IoT apps. Testing IoT apps to remove bugs is currently challenging due to a variety of physical devices with which such apps may interact, including devices that were not even available during app development. The proposed work will help develop techniques for testing IoT apps efficiently and for enforcing safety and security constraints on their run-time behavior. More specifically, the proposed work is centered around three technical thrusts: 1) creating virtual device models to help efficiently test IoT apps systematically without knowing the precise details of physical devices that the apps will control in advance; 2) automating test development for an IoT app to check safety and security specifications against a flexible set of devices; and 3) providing support for enforcement of specifications at run-time for security and safety assertions. The work includes extensive experimentation and evaluation using diverse devices and will represent a significant advance in hardening this important spaces
Performance Period: 01/01/2017 - 12/31/2019
Institution: University of Michigan Ann Arbor
Sponsor: National Science Foundation
Award Number: 1646392
CPS:TTP Option: Synergy: Collaborative Research: Internet of Self-powered Sensors - Towards a Scalable Long-term Condition-based Monitoring and Maintenance of Civil Infrastructure
Lead PI:
Shantanu Chakrabartty
Abstract
This research investigates a cyber-physical framework for scalable, long-term monitoring and maintenance of civil infrastructures. With growth of the world economy and its population, there has been an ever increasing dependency on larger and more complex networks of civil infrastructure as evident in the billions of dollars spent by the federal, state and local governments to either upgrade or repair transportation systems or utilities. Despite these large expenditures, the nation continues to suffer staggering consequences from infrastructural decay. Therefore, paramount to the concept of a smart city of the future is the concept of smart civil infrastructure that can self-monitor itself to predict any impending failures and in the cases of extreme events (e.g. earthquakes) identify portions that would require immediate repair, and prioritize areas for emergency response. A goal of this research project is to make significant progress towards this grand vision by investigating a framework of infrastructural Internet-of-Things (i-IoT) using a network of self-powered, embedded health monitoring sensors. The collaborative and interdisciplinary nature of this research would provide opportunities for unique outreach programs involving undergraduate and graduate students in technical areas, e.g., sensors, IoTs and structural health monitoring. The project would also provide avenues for disseminating the results of this research to stakeholders in the state governments and for translating the results of the research into field deployable prototypes. This research addresses different elements of the proposed i-IoT framework by bringing together expertise from three universities in the area of self-powered sensors, energy scavenging processors, structural health monitoring and earthquake engineering. At the fundamental level, the project involves investigating self-powered sensors that will require zero maintenance and can continuously operate over the useful lifespan of the structure without experiencing any downtime. The challenge in this regard is that sensors need to occupy a small enough volume such that an array of these devices could be easily embedded and can provide accurate spatial resolution in structural imaging. This research is also investigates techniques that would enable real time wireless collection of data from an array of self-powered sensors embedded inside a structure, without taking the structure out-of-service. The methods to be explored involve combining the physics of energy scavenging, transduction, rectification and logic computation to improve the system's energy-efficiency and reduce the system latency. At the algorithmic level the project explores novel structural failure prediction and structural forensic algorithms based on historical data collected from self-powered sensors embedded at different spatial locations. This includes kernel algorithms that can exploit the data to quickly identify the most vulnerable part of a structure after a man-made or a natural crisis (for example an earthquake). Finally, the technology translation plan for this research is to validate the proposed i-IoT framework in real-world deployment, which includes buildings, multi-span bridges and highways.
Performance Period: 09/01/2016 - 08/31/2020
Institution: Washington University in St. Louis
Sponsor: National Science Foundation
Award Number: 1646380
CPS: Breakthrough: Secure Interactions with Internet of Things
Lead PI:
Kang Shin
Abstract
The objective of this research is to (1) gain insights into the challenges of securing interactions in Internet of Things (IoT)deployments, (2) develop a practical framework that mitigates security and privacy threats to IoT interactions, and (3) validate the proposed framework in a medium-scale IoT testbed and through user studies. The emerging IoT computing paradigm promises novel applications in almost all sectors by enabling interactions between users, sensors, and actuators. These interactions can take the form of device-to-device (e.g., Bluetooth Low Energy (BLE)) or human-to-device (e.g., voice control). By exploiting vulnerabilities in these interaction surfaces, an adversary can gain unauthorized access to the IoT, which enables tracking, profiling and posing harm to the user. With the thousands of diverse IoT manufacturers, developers, and devices, it is very challenging, if not impossible, to ensure all devices are properly secured at production and kept up-to-date after production. IoT users and administrators have to place their trust in a set of devices, with the least secure device breaking the security chain. By shifting the trust base from the various manufacturers and developers to a single framework under the user's control, deploying IoT devices will be more feasible and less vulnerable. The proposed framework will help advance the national health, prosperity and welfare, and also secure the national defense. Securing IoT interface surfaces as case studies will be integrated in graduate-level courses, and used to train (especially underrepresented and female) students with interdisciplinary topics that require a balanced mix of theory and practice, thus developing human resources in the nationally needed areas.The proposed research will also significantly advance the understanding of the challenges to secure IoT interaction surfaces in practice, thus promoting the progress of science. This project will establish a general direction to secure interactions in the current and future IoT deployments. It will offer an additional protection layer in the cases where security cannot be properly built-in and maintained.
Performance Period: 10/01/2016 - 09/30/2019
Institution: University of Michigan Ann Arbor
Sponsor: National Science Foundation
Award Number: 1646130
CPS: Synergy: Collaborative Research: Towards Dependable Self-Powered Things for the IoT
Lead PI:
Susan Troiler-McKinstry
Abstract
Scaling the Internet of Things (IoT) to billions and possibly trillions of "things" requires transformative advances in the science, technology, and engineering of cyber-physical systems (CPS), with none more pressing or challenging than the power problem. Consider that if every device in a 1 trillion IoT network had a battery that lasted for a full five years, over 500 million batteries would need to be changed every day. Clearly, a battery-powered IoT is not feasible at this scale due to both human resource logistics and environmental concerns. There is a need for a battery-less approach that dependably meets functionality requirements using energy harvested from the physical world. This project brings together experts in materials, devices, circuits, and systems to pursue a holistic approach to self-powered wireless devices deployed in real-world environments and IoT systems and applications. In addition, educational and outreach activities will help develop the workforce for this relatively new field with the holistic, materials-to-systems perspective that will be necessary to lead innovation in this space.A critical challenge that this project addresses is that both optimal device operation and energy harvester efficiency are heavily dependent on physical world dynamics, and thus, self-powered devices that are statically configured or that just respond to instantaneous conditions are unlikely to provide the dependability required for many IoT systems and applications. To address this fundamental and critically enabling challenge, data collections will be performed to study the physical world dynamics that impact device operation and harvester efficiency, such as ambient conditions, electromagnetic interference, and human behavior. This scientific study will lead to the development of dynamic models that will, in turn, be used to develop algorithms to dynamically configure devices and harvesters based not only on past and current conditions but also on predictions of future conditions. These algorithms will then be used to dynamically configure technological innovations in ultra-low power device operation and ultra-high efficiency energy harvesting to engineer and operate dependable self-powered things for the IoT.
Performance Period: 09/15/2016 - 08/31/2019
Institution: Pennsylvania State University
Sponsor: National Science Foundation
Award Number: 1646399
EAGER: Collaborative Research: Empowering Smart Energy Communities: Connecting Buildings, People, and Power Grids
Lead PI:
David Corman
Abstract
By 2050, 70% of the world's population is projected to live and work in cities, with buildings as major constituents. Buildings' energy consumption contributes to more than 70% of electricity use, with people spending more than 90% of their time in buildings. Future cities with innovative, optimized building designs and operations have the potential to play a pivotal role in reducing energy consumption, curbing greenhouse gas emissions, and maintaining stable electric-grid operations. Buildings are physically connected to the electric power grid, thus it would be beneficial to understand the coupling of decisions and operations of the two. However, at a community level, there is no holistic framework that buildings and power grids can simultaneously utilize to optimize their performance. The challenge related to establishing such a framework is that building control systems are neither connected to, nor integrated with the power grid, and consequently a unified, global optimal energy control strategy at a smart community level cannot be achieved. Hence, the fundamental knowledge gaps are (a) the lack of a holistic, multi-time scale mathematical framework that couples the decisions of buildings stakeholders and grid stakeholders, and (b) the lack of a computationally-tractable solution methodology amenable to implementation on a large number of connected power grid-nodes and buildings. In this project, a novel mathematical framework that fills the aforementioned knowledge gaps will be investigated, and the following hypothesis will be tested: Connected buildings, people, and grids will achieve significant energy savings and stable operation within a smart city. The envisioned smart city framework will furnish individual buildings and power grid devices with custom demand response signals. The hypothesis will be tested against classical demand response (DR) strategies where (i) the integration of building and power-grid dynamics is lacking and (ii) the DR schemes that buildings implement are independent and individual. By engaging in efficient, decentralized community-scale optimization, energy savings will be demonstrated for participating buildings and enhanced stable operation for the grid are projected, hence empowering smart energy communities. To ensure the potential for broad adoption of the proposed framework, this project will be regularly informed with inputs and feedback from Southern California Edison (SCE). In order to test the hypothesis, the following research products will be developed: (1) An innovative method to model a cluster of buildings--with people's behavior embedded in the cluster's dynamics--and their controls so that they can be integrated with grid operation and services; (2) a novel optimization framework to solve complex control problems for large-scale coupled systems; and (3) a methodology to assess the impacts of connected buildings in terms of (a) the grid's operational stability and safety and (b) buildings' optimized energy consumption. To test the proposed framework, a large-scale simulation of a distribution primary feeder with over 1000 buildings will be conducted within SCE?s Johanna and Santiago substations in Central Orange County.
Performance Period: 09/01/2016 - 08/31/2018
Institution: University of California-Riverside
Sponsor: National Science Foundation
Award Number: 1637258
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