This paper deals with the design ripple-free deadbeat controllers for sampled-data systems. Given a prescribed settling time, the design problem is tackled by computing a ripple-free deadbeat controller that optimizes an H2 performance criterion. This criterion accounts for the quality of the tracking response and for the control energy necessary to achieve the deadbeat behavior. Our main resul...

In a conventional three phase Brushless DC machine with 120° electrical conduction, Harmonics and commutation torque ripple occurs because of changeover of load current from one phase to another at every 60 electrical degrees. This paper presents techniques for diminishing the harmonics and torque ripples in sensor Brushless DC motor. This torque ripple reduction techniques based on voltage con...

This paper presents high speed direct digital frequency synthesizer (DDFS) based on pipelining phase accumulator (PA). The proposed 12-bit PA contains three pipelining stages with 4-bit carry-lookahead adder (CLA) with the carries ripple between these stages. Comparing results between similar phase accumulator designed with ripple carry adder on, Cyclone III FPGA platform reveals that the propo...

The observations will be used to validate existing models and to develop new models for ripple geometry as a function of forcing hydrodynamics and seabed characteristics. The observations will also have a smaller focus on small scale sediment transport processes over ripples and larger scale wave field variability over spatially variable ripples. The small scale sediment transport process obser...

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China's continuing evolution toward a market economy has generated ripple effects that are changing most of its economic institutions. One interesting institution cast adrift in this sea of change is the union. While formerly an instrument of the state, the certainty of this role is no more. Issues arise at to how the Chinese union will now evolve, and to what degree it will resemble the wester...

Ripples are sharp-wave-associated field oscillations (100-300 Hz) recorded in the hippocampus during behavioral immobility and slow-wave sleep. In epileptic rats and humans, a different and faster oscillation (200-600 Hz), termed fast ripples, has been described. However, the basic mechanisms are unknown. Here, we propose that fast ripples emerge from a disorganized ripple pattern caused by unr...

The hippocampus plays a key role in the acquisition of new memories for places and events. Evidence suggests that the consolidation of these memories is enhanced during sleep. At the neuronal level, reactivation of awake experience in the hippocampus during sharp-wave ripple events, characteristic of slow-wave sleep, has been proposed as a neural mechanism for sleep-dependent memory consolidati...

The formation of ripple structures on ion bombarded semiconductor surfaces is examined theoretically. Previous models are discussed and a new nonlinear model is formulated, based on the infinitesimal local atomic relocation induced by elastic nuclear collisions in the early stages of collision cascades and an associated density change in the near surface region. Within this framework ripple st...