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Despite availability of multiple orthogonal communication channels on common sensor network platforms, such as MicaZ motes, and despite multiple simulation-supported designs of multi-channel MAC protocols, most existing sensor networks use only one channel for communication, which is a source of bandwidth inefficiency. In this work, we design, implement,(More)
The paper presents a feedback scheduling strategy for multiple control tasks that uses feedback from the plant states to distribute the computing resources optimally among the tasks. Linear-quadratic controllers are analyzed, and expressions relating the expected cost to the sampling period and the plant state are derived and used for on-line samplerate(More)
Embedded systems are becoming increasingly networked and are deployed in application areas that require close interaction with their physical environment. Examples include distributed mobile agents and wireless sensor/actuator networks. The complexity of these applications make cosimulation a necessary tool during system development. This paper presents a(More)
Co-simulation of controller task execution, network transmissions, and continuous plant dynamics. Accomplished by providing models of real-time kernels and networks as Simulink blocks User code in the form of tasks and interrupt handlers is modeled by MATLAB or C-code Investigate the true, timely behaviour of time or event-triggered control loops, subject(More)
Most currently deployed sensor networks use the same channel to communicate information among nodes. This is a source of great inefficiency as it poorly utilizes the available wireless spectrum. This paper takes advantage of radio capabilities of MicaZ motes that can communicate on multiple frequencies as specified in the 802.15.4 standard. We consider the(More)
1. Background The use of control-based methods for resource management in real-time computing and communication systems has gained a substantial interest recently. Applications areas include performance control of web-servers, dynamic resource management in embedded systems, traffic control in communication networks, transaction management in database(More)
The paper presents two recently developed, MATLAB-based analysis tools for real-time control systems. The first tool, called JITTERBUG, is used to compute a performance criterion for a control loop under various timing conditions. The tool makes it easy to quickly judge how sensitive a controller is to implementation effects such as slow sampling, delays,(More)
Delay-tolerant networks (DTNs), where no connected path generally exists between a source and a destination at any given time, present significant challenges from a routing perspective. A plethora of routing approaches have been previously introduced that make use of node mobility models or probabilistic models of network topology. In this paper, we offer a(More)
This paper introduces the area of Cyber-Physical Systems (CPS) and describes the relation to Modeli-ca and Modelica-based tools. Special aspects of CPS applications that should make Modelica well suited for their modeling and simulation are highlighted. Recent Modelica developments facilitating integrated model-based system development applicable to CPS are(More)