Current Issue : January - March Volume : 2016 Issue Number : 1 Articles : 4 Articles
A specially designed microcontroller with event-driven sensor data processing unit (EPU) is proposed to provide energy-efficient\nsensor data acquisition for Internet of Things (IoT) devices in rare-event human activity sensing applications. Rare-event sensing\napplications using a remotely installed IoT sensor device have a property of very long event-to-event distance, so that the inaccurate\nsensor data processing in a certain range of accuracy error is enough to extract appropriate events from the collected sensing data.\nThe proposed signal-to-event converter (S2E) as a preprocessor of the conventional sensor interface extracts a set of atomic events\nwith the specific features of interest and performs an early evaluation for the featured points of the incoming sensor signal. The\nconventional sensor data processing such as DSPs or software-driven algorithm to classify the meaningful event from the collected\nsensor data could be accomplished by the proposed event processing unit (EPU). The proposed microcontroller architecture\nenables an energy efficient signal processing for rare-event sensing applications.The implemented system-on-chip (SoC) including\nthe proposed building blocks is fabricated with additional 7500 NAND gates and 1-KB SRAM tracer in 0.18um CMOS process,\nconsuming only 20% compared to the conventional sensor data processing method for human hand-gesture detection....
Active vibration control of an axially translating robot arm with rotating-prismatic joint using self-sensing actuator is investigated.\nThe equations of the system are derived by Lagrange�s equation with the assumed mode method. The displacement and velocity\ncontrol law is used to configure the self-sensing actuator, which provides the active damping and stiffness effect to the structure.The\nnumerical simulations reveal that the tip deflection of the arm can be effectively reduced by the self-sensing actuator.The amplitude\nof sensor voltage is inversely proportional to the length of axially translating arm. And higher feedback control gain results in lower\nsensor voltages and vibration amplitudes....
Quantum dots (QDs), have great potential for fabricating optical sensing devices and imaging biomaterial degradation in vivo.\nIn the present study, 2-mercaptoethylamine- (MEA-) and mercaptopropionic acid- (MPA-) capped CdTe-QDs were physically\nincorporated in silk films that contained a high content (>30%) of crystalline beta-sheet structure. The beta-sheets were induced\nby the addition of glycerol, water annealing, glycerol/annealing, or treatment with methanol. Incorporation of QDs did not\ninfluence the formation of beta-sheets. When the films were extracted with water, most QDs remained associated with the silk,\nbased on the retention of photoluminescence in the silk films and negligible photoluminescence in the extracts. Compared to the\nsolution state, photoluminescence intensity significantly decreased for MEA-QDs but not forMPA-QDs in the silk films, while the\nemission maximum blue shifted (ââ?°Ë?4 nm) slightly for both. Further film digestion using protease XIV, alpha-chymotrypsin, and the\ncombination of the two proteases suggested that QDs may be bound to the silk beta-sheet regions but not the amorphous regions.\nQDs photoluminescence in silk films was quenched when the concentration of hydrogen peroxide (H2O2) was above 0.2-0.3 mM,\nindicating the QDs-incorporated silk films can be used to report oxidation potential in solution....
This paper deals with passive monomodal vibration control by shunting piezoelectric actuators to electric impedances constituting\nthe series of a resistance and an inductance. Although this kind of vibration attenuation strategy has long been employed, there are\nstill unsolved problems; particularly, this kind of control does suffer from issues relative to robustness because the features of the\nelectric impedance cannot be adapted to changes of the system. This work investigates different algorithms that can be employed\nto optimise the values of the electric components of the shunt impedance. Some of these algorithms derive from the theory of the\ntuned mass dampers. First a performance analysis is provided, comparing the attenuation achievable with these algorithms. Then,\nan analysis and comparison of the same algorithms in terms of robustness are carried out. The approach adopted herein allows\nidentifying the algorithm capable of providing the highest degree of robustness and explains the solutions that can be employed to\nresolve some of the issues concerning the practical implementation of this control technique.The analytical and numerical results\npresented in the paper have been validated experimentally by means of a proper test setup....
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