Murti V. Salapaka

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Distributed averaging over a large network is a well studied problem that converges asymptotically; however, existing protocols does not provide a way for each node to distributively detect the occurrence of convergence. In this paper a method is developed to distributively determine when the consensus has reached within a given error margin. In absence of(More)
In this paper, the design of controllers that incorporate structural and multiobjective performance requirements is considered. The control structures under study cover nested, chained, hierarchical, delayed interaction and communications, and symmetric systems. Such structures are strongly related to several modern-day and future applications including(More)
Several methods have been developed for joint working and spare capacity planning in survivable wavelength-division-multiplexing (WDM) networks. These methods have considered a static traffic demand and optimized the network cost assuming various cost models and survivability paradigms. Our interest primarily lies in network operation under dynamic traffic.(More)
This paper presents the identification and control of piezoelectric positioners used in atomic force microscopes (AFM) with the goal of improving probe positioning on the sample surface. A novel sensor was developed for this task and employed to infer a sixth order linear two input two output model of the piezo’s lateral dynamics. The piezo model was used(More)
The atomic force microscope ~AFM! is a powerful tool for investigating surfaces at atomic scales. Harmonic balance and power balance techniques are introduced to analyze the tapping-mode dynamics of the atomic force microscope. The harmonic balance perspective explains observations hitherto unexplained in the AFM literature. A nonconservative model for the(More)
In this paper, we consider two important objectives of network operation: (i) capacity minimization and (ii) revenue maximization. For capacity minimization, we formulate three operational phases in survivable WDM network operation viz., initial call set up, short/medium-term reconfiguration, and long-term reconfiguration. All three phases are derived from(More)
This paper addresses the development of distributed models for the piezoceramic positioning mechanisms employed in current atomic force microscope designs. Two common con gurations for positioning mechanisms employ stacked actuators utilizing d33 motion and piezoceramic shells utilizing a d31 motion. In both cases, the relation between input voltages and(More)
There is an increasing need for high density data storage devices driven by the increased demand of consumer electronics. In this work, we consider a data storage system that operates by encoding information as topographic profiles on a polymer medium. A cantilever probe with a sharp tip (few nm radius) is used to create and sense the presence of(More)