103,098 research outputs found
Pentaquarks
Since LEPS collaboration reported the first evidence of pentaquark
in early 2003, eleven other experimental groups have confirmed this exotic
state while many other groups didn't see any signal. If this state is further
established by future high statistical experiments, its discovery shall be one
of the most important events in hadron physics for the past three decades. This
exotic baryon with such a low mass and so narrow a width imposes a big
challenge to hadron theorists. Up to now, there have appeared more than two
hundred theoretical papers trying to interpret this charming state. I will
review some important theoretical developments on pentaquarks based on my
biased personal views.Comment: Review Commissioned by International Journal of Modern Physics
Estimation Schemes for Networked Control Systems Using UDP-Like Communication
In this work we consider a class of networked control systems (NCS) when the control signal is sent to the plant via a UDP-like communication protocol, the controller sends a communication packet to the plant across a lossy network but the controller does not receive any acknowledgement signal indicating the status of reception/delivery of the control packet. Standard observer based estimators assume the estimator has knowledge of what control signal is applied to the plant, but under the UDP-like communication scheme the estimator does not know what control is applied. Continuing previous work, we present a simple estimation algorithm consisting of a state estimator and mode observer. For single input systems we can add an extra control signal that guarantees recovery of the fate of the control packet. Using a modified state feedback with the added input we can guarantee the estimation error is bounded as is the expected value of the state. This extra input is removed and sufficient conditions on the system properties are given to assure the estimation remain bounded. Comparisons are made between the algorithm presented and the method of unknown input observer. Simulations are provided to demonstrate the algorithm
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