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Modern embedded computing systems tend to be heterogeneous in the sense of being composed of subsystems with very different characteristics, that communicate and interact in a variety of ways—synchronous or asynchronous, buffered or unbuffered, etc. Obviously, when designing such systems, a modeling language needs to reflect this het-erogeneity. Today's(More)
We present an " opportunistic " transmission scheduling policy that exploits time-varying channel conditions and maximizes the system performance stochastically under a certain resource allocation constraint. We establish the optimality of the scheduling scheme, and also that every user experiences a performance improvement over any non-opportunistic(More)
This paper presents a hierarchical hybrid system modeling and simulation framework using the Ptolemy I1 environment. Ptolemy I1 is a system-level design tool that supports the integration of multiple models of computation. The modeling of hierarchical hybrid systems is achieved by combining continuous-time models with finite state autom-ata. Breakpoint(More)
—Complex control systems are heterogeneous, in the sense of discrete computer-based controllers interacting with continuous physical plants, regular data sampling interleaving with irregular communication and user interaction, and multi-layer and multimode control laws. This heterogeneity imposes great challenges for control system design in terms of(More)
  • John Davis, Mudit Goel, Christopher Hylands, Bart Kienhuis, Edward A Lee, Jie Liu +7 others
  • 1994
The Ptolemy project studies heterogeneous modeling, simulation, and design of concurrent systems. The focus is on embedded systems, particularly those that mix technologies, including for example analog and digital electronics, hardware and software, and electronics and mechanical devices (including MEMS, microelectromechanical systems). The focus is also(More)
In the present study, the antidepressant-like effect of bacopaside I, a saponin compound present in the Bacopa monniera plant, was evaluated by behavioral and neurochemical methods. Bacopaside I (50, 15 and 5 mg/kg) was given to mice via oral gavage for 7 successive days. The treatment significantly decreased the immobility time in mouse models of despair(More)