The aim of this project is to lay down the foundations of a novel approach to real-time control of networked cyber-physical systems (CPS) that leverages their cooperative nature. Most networked controllers are not implementable over embedded digital computer systems because they rely on continuous time or synchronous executions that are costly to enforce. These assumptions are unrealistic when faced with the cyber-physical world, where the interaction between computational and physical components is multiplex, information acquisition is subject to error and delay, and agent schedules are asynchronous. Even without implementation obstacles, the periodic availability of information leads to a wasteful use of resources. Tuning controller execution to the task at hand offers the potential for great savings in communication, sensing, and actuation. The goal of this project is to bring this opportunity to fruition by combining event- and self-triggered control ideas into a unified approach that inherits the best of both models. The key conceptual novelty is for agents to make promises to one another about their future states and warn each other if they later decide to break them. The information provided by promises allows agents to autonomously determine when fresh information is needed, resulting in an efficient network performance. Networked cyber-physical systems are transforming the way society interacts with the physical world. Advances in this field are extending the range of human capabilities in an increasing number of areas with high societal and economic impact, such as smart energy, intelligent transportation, advanced manufacturing, health technology, and the environment. This project contributes to the science and technology of cyber-physical systems by developing a novel principled approach for networked systems to operate efficiently and cope with the sources of uncertainty present in real-word applications. The potential benefits are real-time operation in a wide range of application domains of cooperative cyber-physical systems with a superior level of efficiency and robustness than currently possible. The project promises to contribute to the training of a new generation of engineering students at UC San Diego with the skills necessary to deal with this type of multi-faceted systems and applications. The plan includes undergraduate student involvement in research, graduate supervision and curriculum development, outreach to high-school students, retention of minorities in STEM disciplines, and broad dissemination activities.

The electric power grid is a national critical infrastructure that is increasing vulnerable to malicious physical and cyber attacks. As a result, detailed data describing grid topology and components is considered highly sensitive information that can be shared only under strict non-disclosure agreements. There is also increasing need to foster cooperation among the growing number of participants in microgrid-enabled electric marketplace. However, to maintain their economic competitiveness, the market participants are not inclined to share sensitive information about their grid with other participants. Motivated by this need for increased cyber-physical security and economic confidentiality, the project is developing techniques to obfuscate sensitive design information in power system models without jeopardizing the quality of the solutions obtained from such models. Specifically, solution approaches have been developed to hide sensitive structural information in Direct Current (DC) Optimal Power Flow models. These approaches are currently being extended to Alternating Current (AC) Optimal Power Flow models. The project is also developing secure multi-party methods where the market participants collectively optimize the grid operation while only sharing encrypted private sensitive information. Finally, the project is incorporating secure market operations in jointly solving the Optimal Power Dispatch problem without revealing sensitive private information from each participant to other participants. The techniques developed in this project have the potential to broadly impact areas beyond power systems. The general principles developed in the project can be used to mask sensitive information in many problems that can be formulated as a linear or non-linear programming optimization.

A hybrid system is a dynamical model that describes the coupled evolution of both continuous-valued variables and discrete patterns. A prime example of such a system is a power electronic circuit, where the semiconductor transistors behave as ideal switches whose switching actions effectively change the circuit topology (i.e., the discrete pattern) that in turn defines the dynamics of currents and voltages (i.e., the continuous variables) and hence the switching actions. There have been two disparate paths to analyzing and designing hybrid systems. One path is to focus on the discrete patterns and achieve scalable, high-level analysis and synthesis. The other path is to pay attention to the dynamics of continuous variables and guarantee low-level properties such as stability and transient performance. The research objective of this proposal is to bridge these approaches by enabling a synergy between the discrete pattern based and continuous variable based approaches. The theory and algorithms developed in course of this work will be applied to digital control of power electronic circuits in order to overcome the scalability and stability issues suffered by existing approaches to power electronics design. The PIs envision that a successful completion of the project will establish a new paradigm in the analysis and design of hybrid systems, and thus contribute to the needs of modern society, such as microgrids and embedded generation, where power electronic circuits are integral parts. The research will be integrated into educational programs through student mentoring and development of courses and laboratory equipment. The PIs will make a special effort to recruit women and minority students. These broader-impact programs will help innovate science and engineering education and prepare for next-generation CPS scientists and engineers.

The objective of this research is to develop a comprehensive theoretical and experimental cyber-physical framework to enable intelligent human-environment interaction capabilities by a synergistic combination of computer vision and robotics. Specifically, the approach is applied to examine individualized remote rehabilitation with an intelligent, articulated, and adjustable lower limb orthotic brace to manage Knee Osteoarthritis, where a visual-sensing/dynamical-systems perspective is adopted to: (1) track and record patient/device interactions with internet-enabled commercial-off-the-shelf computer-vision-devices; (2) abstract the interactions into parametric and composable low-dimensional manifold representations; (3) link to quantitative biomechanical assessment of the individual patients; (4) facilitate development of individualized user models and exercise regimen; and (5) aid the progressive parametric refinement of exercises and adjustment of bracing devices. This research and its results will enable us to understand underlying human neuro-musculo-skeletal and locomotion principles by merging notions of quantitative data acquisition, and lower-order modeling coupled with individualized feedback. Beyond efficient representation, the quantitative visual models offer the potential to capture fundamental underlying physical, physiological, and behavioral mechanisms grounded on biomechanical assessments, and thereby afford insights into the generative hypotheses of human actions. Knee osteoarthritis is an important public health issue, because of high costs associated with treatments. The ability to leverage a quantitative paradigm, both in terms of diagnosis and prescription, to improve mobility and reduce pain in patients would be a significant benefit. Moreover, the home-based rehabilitation setting offers not only immense flexibility, but also access to a significantly greater portion of the patient population. The project is also integrated with extensive educational and outreach activities to serve a variety of communities.

Intellectual Merit: Recent developments in nanostructures manufacturing, sensing and wireless networking, will soon enable us to deploy Flow-based Cyber-Physical Systems equipped with sensing and actuation capabilities for a broad range of applications. Some of these applications will be safety critical, including water distribution monitoring (i.e., critical national infrastructure systems particularly vulnerable to a variety of attacks, including contamination with deadly agents) and interventional medicine (i.e., a medical branch that makes use of tiny devices introduced in a living body through small incisions, to detect and treat diseases). The goal of this project is to advance our fundamental understanding, through a robust mathematical framework, of emerging field of Flow-based Cyber-Physical System. The project develops new architectures, models, metrics, algorithms and protocols for optimal sensing, communication and actuation in Flow-based Cyber-Physical System deployed on-demand (i.e., reactively, when sensing and actuation is needed) or proactively. Flow-based Cyber Physical Systems consist of mobile sensor nodes and static nodes, aware of their location. For stringent requirements (e.g., form factor, cost, energy budget) nodes may or may not possess node-to-node communication capabilities. Due to the lack of localization infrastructure, mobile sensor nodes infer their location only by proximity to static nodes. Sensor nodes are moved by the flow in the network, detect events of interest and proximity to static nodes, communicate and actuate. This research will enable, for example, water distribution monitoring systems to accurately and timely detect events of interest in the infrastructure and to react to these events. It may enable doctors to detect diseases and deliver medication with microscopic precision. Broader Impacts: Ultimately, the outcomes of this research will have impact on CPS that operate in critical modes and environments and control critical infrastructures and medical applications. The results from this research may also foster new research directions in CPS applications. The PI will integrate the research results in newly approved courses on CPS at Texas A&M and disseminate course materials online through the project website and Rice University Connections Consortium. This project will also offer research opportunities to undergraduate students, underrepresented groups, and high school students participating in the Texas Science Olympiad and National Science Olympiad.

This project develops the foundations of modeling, synthesis and development of verified medical device software and systems, from verified closed-loop models of the device and organ(s). The effort spans both implantable medical devices such as cardiac pacemakers and physiological control systems such as drug infusion pumps that have multiple networked medical systems. In both cases, the devices are physically connected to the body and exert direct control over the physiology and safety of the patient-in-the-loop. The goal is to ensure the device will never drive the patient into an unsafe state, while providing effective therapy. The contributions of are in three areas: closed-loop patient-device modeling; quantitative verification for optimized patient-specific devices; platforms for life-critical systems. Integrated modeling methodologies are developed to produce both the functional physiological signals, for clinically relevant testing with a medical device, and also generate the formal timing of device-patient interaction for formal verification. Starting with the problem of verifying the safety and correctness of medical device software, probabilistic patient models based on physiological data are then used to develop quantitative verification techniques to maintain the therapy?s efficacy on the patient and operational efficiency of the device. To facilitate participation of the CPS community, the Food and Drug Administration (FDA), physicians and manufacturers, open source libraries of device/patient models, software tools for verification and model translation and hardware platforms for testing with real medical devices are developed. The closed-loop design and verification techniques for medical device software and patients, developed here, have direct potential benefits on human health, and the quality and cost of medical care. Design of bug-free and safe medical device software is challenging, especially in complex implantable devices that control and actuate organs who's response is not fully understood. Safety recalls of pacemakers and implantable ?cardioverter? defibrillators between 1990 and 2000 affected over 600,000 devices. Of these, 200,000 or 41%, were due to firmware issues (i.e. software) that continue to increase in frequency. There is currently no formal methodology or open experimental platform to test and verify the correct operation of medical device software within the closed-loop context of the patient. If successful, this project has potential to not only increase the safety of such devices, but also to accelerate the development and certification process. The latter could reduce costs, and shorten the time to market for new devices. The project also has an extensive education and outreach component, including curriculum development in medical cyber-physical systems, involvement of undergraduate and graduate students in research, and cooperation with hospitals, makers of medical devices, and the FDA. The cross-cutting nature of the project brings together communities involving clinical physicians, electrical engineers, computer scientists and regulators of health care safety.

This proposed task provides the support for a community meeting by the Federal agencies, whose mission is to advance the science and technology of cyber security, with leading experts and researchers in academia, industry, and government at the Gaylord National Hotel and Convention Center, National Harbor, Maryland. This meeting will focus on recent progress in developing the scientific foundation for the design and analysis of trusted systems. Over 150 leaders from government, industry, and the academic community met to discuss new and ongoing programs in security science being pursued by U.S. government research sponsors, and an exciting new Cybersecurity Research Institute recently established in the U.K. The presentations included work in a broad range of disciplines including mathematics, computer science, behavioral science, economics, physics, and biology. The meeting introduced a new Science of Security Virtual Organization website designed to promote research collaboration and community development. NSA's Director of Research concluded the meeting with the announcement of a Cybersecurity Science Paper Competition.

This project's objective is to enable assertion-driven development and debugging of cyber-physical systems (CPS), in which required conditions are formalized as part of the design. In contrast with traditional uses of assertions in software engineering, CPS demand a tight coupling of the cyber with the physical, including in system validation. This project uses mathematical models of key physical attributes to guide creation of assertions, to identify inconsistent or infeasible assertions, and to localize potential causes for CPS failures. The goal is to produce methods and tools that use physical models to guide assertion-based verification of cyber-physical systems. An assertion language is being developed that is founded in mathematical logic while providing the familiarity of commonly used programming languages. This foundation enables new automated debugging techniques for CPS. By leveraging models that encode laws of physics and an automated decision procedure, the techniques being developed help identify causes of CPS failures by distinguishing inconsistent or infeasible physical states from valid ones. This model-based approach incorporates means to assess these physical states using both probabilistic and non-probabilistic measures. Two safety-critical applications guide the research and demonstrate the impact on the development of CPS: coordinated control of autonomous vehicles and monitoring and control of left-ventricular assist devices (LVADs). The focus on these safety-critical applications are motivational for recruiting and educating engineering students who have high expectations for how their lives should be enabled by computing advances. Further, this research advances methods needed to validate safe and effective CPS, promoting the public's confidence in their application to safety-critical systems.

Cyber physical systems (CPSs) are merging into major mobile systems of our society, such as public transportation, supply chains, and taxi networks. Past researchers have accumulated significant knowledge for designing cyber physical systems, such as for military surveillance, infrastructure protection, scientific exploration, and smart environments, but primarily in relatively stationary settings, i.e., where spatial and mobility diversity is limited. Differently, mobile CPSs interact with phenomena of interest at different locations and environments, and where the context information (e.g., network availability and connectivity) about these physical locations might not be available. This unique feature calls for new solutions to seamlessly integrate mobile computing with the physical world, including dynamic access to multiple wireless technologies. The required solutions are addressed by (i) creating a network control architecture based on novel predictive hierarchical control and that accounts for characteristics of wireless communication, (ii) developing formal network control models based on in-situ network system identification and cross-layer optimization, and (iii) designing and implementing a reference implementation on a small scale wireless and vehicular test-bed based on law enforcement vehicles. The results can improve all mobile transportation systems such as future taxi control and dispatch systems. In this application advantages are: (i) reducing time for drivers to find customers; (ii) reducing time for passengers to wait; (iii) avoiding and preventing traffic congestion; (iv) reducing gas consumption and operating cost; (v) improving driver and vehicle safety, and (vi) enforcing municipal regulation. Class modules developed on mobile computing and CPS will be used at the four participating Universities and then be made available via the Web.

This project aims to achieve key technology, infrastructure, and regulatory science advances for next generation medical systems based on the concept of medical application platforms (MAPs). A MAP is a safety/security-critical real-time computing platform for: (a) integrating heterogeneous devices and medical IT systems, (b) hosting application programs ("apps") that provide medical utility through the ability to both acquire information and update/control integrated devices, IT systems, and displays. The project will develop formal architectural and behavioral specification languages for defining MAPs, with a focus on techniques that enable compositional reasoning about MAP component interoperability and safety. These formal languages will include an extensible property language to enable the specification of real-time, quality-of-service, and attributes specific to medical contexts that can be leveraged by code generation, testing, and verification tools. The project will work closely with a synergistic team of clinicians, device industry partners, regulators, and medical device interoperability and safety standard organizations to develop an open source MAP innovation platform to enable key stakeholders within the nation's health care ecosphere to identify, prototype, and evaluate solutions to key technology and regulatory challenges that must be overcome to develop a commodity market of regulated MAP components. Because MAPs provide pre-built certified infrastructure and building blocks for rapidly developing multi-device medical applications, this research has the potential to usher in a new paradigm of medical system that significantly increases the pace of innovation, lowers development costs, enables new functionality by aggregating multiple devices into a system of systems, and achieves greater system safety.