@conference {
	title = {Numerical Study on Joint Quantization and Control Under Block-Coding},
	author = {Tan, Xiaobo., Xi, Wei., Baras, John S.},
	year = {2004},
	month = {12/2004},
	abstract = {This paper addresses the joint quantization and control problem for hidden Markov chains with variable-length block-coding. The aim is to understand the impact of communication bandwidth and information delay (due to block-coding) on the control performance. A heuristic algorithm is developed to solve the dynamic programming (DP) equation through the introduction of a metric on the discrete observation space. Numerical results are presented demonstrating the attention division in block-coding and the tradeoffs between control performance and communication bandwidth.},
	address = {Atlantis, Paradise Island, Bahamas},
	booktitle = {43rd IEEE Conference on Decision and Control},
	pages = {pp. 4515-4520}
}
@conference {
	title = {Control of Autonomous Swarms Using Gibbs Sampling},
	author = {Baras, John S., Tan, Xiaobo.},
	year = {2004},
	month = {12/2004},
	abstract = {A distributed control approach is proposed for self-organization of autonomous swarms. The swarm is modeled as a Markov random field (MRF) on a graph where the (mobile) nodes and their communication/sensing links constitute the vertices and the edges of the graph, respectively. The movement of nodes is governed by the Gibbs sampler. The Gibbs potentials, local in nature, are designed to reflect collective goals such as gathering, dispersion, and linear formation. The algorithm can be run completely in parallel, and hence it is robust and scalable. Simulation results are provided to illustrate the proposed method.},
	address = {Atlantis, Paradise Island, Bahamas},
	booktitle = {43rd IEEE Conference on Decision and Control},
	pages = {pp. 4752-4757}
}
@conference {
	title = {Vision-Based Microtribological Characterization of Linear Microball Bearings},
	author = {Tan, Xiaobo., Modafe, Alireza., Hergert, R., Ghalichechian, N., Shapiro, B, Baras, John S., Ghodssi, R.},
	year = {2004},
	month = {10/2004},
	abstract = {Microball bearings can potentially provide robust and low friction support in micromachines such as micromotors and microgenerators. Their microtribological behavior needs to be investigated for design and control of such micromachines. In this paper a vision-based, non-intrusive measurement method is presented for characterization of friction in linear microball bearings. Infrared imaging is used to directly observe the dynamics of microballs and track the motion of bearing components. It is verified that microballs roll most of the time with occasional sliding or bumping resulting from fabrication nonuniformity. The friction-velocity curve demonstrates evident hysteresis. The dependence of frictional behavior on several factors is studied.},
	address = {Long Beach, California},
	booktitle = {ASME/STLE International Joint Tribology Conference (IJTC04)},
	pages = {pp. 1-6}
}
@article {
	title = {Modeling and Control of Hysteresis in Magnetostrictive Actuators},
	author = {Tan, Xiaobo., Baras, John S.},
	year = {2004},
	month = {07/2004},
	abstract = {A novel dynamic model is proposed for the hysteresis in magnetostrictive actuators by coupling a Preisach operator to an ordinary differential equation, and a parameter identification method is described. An efficient inversion algorithm for a class of Preisach operators with piecewise uniform density functions is then introduced, based upon which an inverse control scheme for the dynamic hysteresis model is presented. Finally, the inversion error is quantified and l1 control theory is applied to improve the robustness of inverse compensation. Simulation and experimental results based on a Terfenol-D actuator are provided.},
	pages = {pp. 1469-1480},
	volume = {Volume 40},
	number = {Issue 9},
	journal = {Automatica}
}
@conference {
	title = {Adaptive Inverse Control of Hysteresis in Smart Materials},
	author = {Tan, Xiaobo., Baras, John S.},
	year = {2004},
	month = {09/2004},
	abstract = {Hysteresis hinders the effective use of smart materials in sensors and actuators. This paper addresses recursive identification and adaptive inverse control of hysteresis in smart material actuators, where hysteresis is modeled by a Preisach operator with a piecewise uniform density function. Two classes of identification schemes are proposed and compared, one based on the hysteresis output, the other based on the time-difference of the output. Conditions for parameter convergence are presented in terms of the input to the Preisach operator. An adaptive inverse control scheme is developed by updating the Preisach operator (and thus its inverse) with the output-based identification method. The asymptotic tracking property of this scheme is established, and for periodic reference trajectories, the parameter convergence behavior is characterized. Practical issues in the implementation of the adaptive identification and inverse control methods are also investigated. Simulation and experimental results based on a magnetostrictive actuator are provided to illustrate the proposed approach.},
	address = {Stuttgart, Germany},
	booktitle = {2004 Nonlinear Control Systems (NOLCOS) IFAC Workshop}
}
@article {
	title = {Adaptive Identification and Control of Hysteresis in Smart Materials},
	author = {Tan, Xiaobo., Baras, John S.},
	year = {2004},
	month = {09/2004},
	abstract = {Hysteresis hinders the effective use of smart materials in sensors and actuators. This paper addresses recursive identification and adaptive inverse control of hysteresis in smart material actuators, where hysteresis is modeled by a Preisach operator with a piecewise uniform density function. Two classes of identification schemes are proposed and compared, one based on the hysteresis output, the other based on the time difference of the output. Conditions for parameter convergence are presented in terms of the input to the Preisach operator. An adaptive inverse control scheme is developed by updating the Preisach operator (and thus its inverse) with the output-based identification method. The asymptotic tracking property of this scheme is established, and for periodic reference trajectories, the parameter convergence behavior is characterized. Practical issues in the implementation of the adaptive identification and inverse control methods are also investigated. Simulation and experimental results based on a magnetostrictive actuator are provided to illustrate the proposed approach.},
	pages = {pp. 827-839},
	volume = {Vol.  50},
	number = {No. 6},
	journal = {IEEE Transactions on Automatic Control.}
}
@conference {
	title = {Recursive Identification of Hysteresis in Smart Materials},
	author = {Tan, Xiaobo., Baras, John S.},
	year = {2004},
	month = {06/2004},
	abstract = {This paper studies recursive identification of hysteresis in smart materials. A Preisach operator with a piece-wise uniform density function is used to model the hysteresis. Persistent excitation conditions for parameter convergence are discussed in terms of the input to the Preisach operator. Two classes of recursive identification schemes are explored, one based on the hysteresis output, the other based on the time difference of the output. Experimental results based on a magnetostrictive actuator are presented.},
	address = {Boston, MA},
	booktitle = {2004 American Control Conference},
	pages = {pp. 3857-3862}
}
@conference {
	title = {A Parallel Queue Structure for Active Queue Management},
	author = {Jou,  Jia-Shiang., Tan, Xiaobo., Baras, John S.},
	year = {2004},
	month = {03/2004},
	address = {Princeton, NJ},
	booktitle = {Annual Conference on Information Sciences and Systems}
}
@conference {
	title = {A Parallel Virtual Queue Structure for Active Queue Management},
	author = {Jou,  Jia-Shiang., Tan, Xiaobo., Baras, John S.},
	year = {2004},
	month = {03/2004},
	abstract = {Performance of the Adaptive RED scheme is susceptible to bursty web traffic. A parallel queue structure was proposed earlier to address this problem, where real time connections (such as web and UDP) and non-real time connections (such as FTP) are served in two different queues with droptail and Adaptive RED policies, respectively. In this paper a modified Adaptive RED scheme is proposed for the second queue to improve the goodput of non-real time connections. In this scheme the queue length thresholds for the Adaptive RED are dynamically determined by the average droppping probability. Simulation shows that the packet dropping probability of the Adaptive RED queue stays within a desired small region. The stability of the queue length variation under this policy is proved under mild conditions.},
	address = {Princeton, New Jersey},
	booktitle = {Proceedings of 38th Conference on Information Sciences and Systems - CISS 2004,},
	pages = {pp. 1-6}
}
