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Networked
Cyber Physical Systems at SRI |
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In an NCPS, information about the physical world (e.g.,
wireless signal strength, sensor readings) is usually acquired via physical
devices, which can be geographically scattered. Hence, the management of an NCPS entails the integration
between a physical layer, which includes the underlying physical devices as
well as the network, and a higher layer, which includes the knowledge
dissemination layer and the application layer that is designed to achieve
global objectives To deal with uncertainty, complexity, and resource
constraints in both communication and computation, the cyber-framework is
concerned with decisions at each layer. For example, assume an application
operating a networked team of mobile robots, i.e., mobile computational
resources with sensors and actuators.
At the application layer, it needs to decide when to perform a local
action (e.g., move forward, sense the temperature of a certain area) to
achieve local goals, which are typically obtained by decomposition from
higher-level goals. Local computations are also needed for tasks such as
information fusion, based on which new goals may be triggered. In [1][3], we
presented a declarative approach to avoid low-level programming by combining
distributed reasoning and asynchronous control. In [2], we presented a case study of a dynamic distributed
optimization and control problem that is not solved using a distributed logic
but directly built on top of the cyber-framework. At the knowledge dissemination layer, a specific strategy
(e.g., deterministic flooding) is chosen to propagate knowledge on top of the
underlying physical network layer.
The global objective needs coordination among the nodes. Knowledge about local solutions needs
to be disseminated through the network to improve overall solution quality.
What kind of knowledge and how often the knowledge should be disseminated
depends on the specific application and its objective. 1. M-O.
Stehr, M. Kim, C. Talcott Toward Distributed Declarative Control of Networked
Cyber-Physical Systems
7th International Conference
on Ubiquitous Intelligence and Computing (UIC'10) Oct. 2010, Xian, China. 2. M. Kim, M-O. Stehr,
J. Kim, S. Ha, An
Application Framework for Loosely Coupled Networked Cyber Physical Systems
8th IEEE/IFIP Conference on Embedded and Ubiquitous Computing (EUC'10) 3. M. Kim,
M-O. Stehr, C. Talcott A Distributed Logic for Networked Cyber-Physical Systems
IPM International Conference on Fundamentals of Software Engineering (FSEN'11), Apr. 2011, Teheran, Iran. |
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Last updated: July
12, 2012