Now showing 1 - 10 of 4225
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    Cross-layer scheduling with infrequent channel and queue measurements
    (01-12-2009)
    Manikandan, C.
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    Rajesh, Sundaresan
    The downlink scheduling problem in multi-queue multi-server systems under channel uncertainty is considered. Two policies that make allocations based on predicted channel states are proposed. The first is an extension of the well-known dynamic backpressure policy to the uncertain channel case. The second is a variant that improves delay performance under light loads. The stability region of the system is characterized and the first policy is argued to be throughput optimal. A recently proposed policy of Kar et al [1] has lesser complexity, but is shown to be throughput suboptimal. Further, simulations demonstrate better delay and backlog properties for both our policies at light loads. © 2009 IEEE.
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    Day ahead scheduling of generation and storage sources in a microgrid using artificial fish swarm algorithm
    (27-09-2017)
    Kumar, K. Prakash
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    Saravanan, B.
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    Non-consistency of energy availability from Renewable Energy Sources needs estimation and scheduling in advance so that the other certain sources of energy like fuel cells, diesel generators, storage devices etc., can be scheduled appropriately to maintain load-generation balance in real time. Evolutionary program techniques are proving handy and reliable in the process. This article uses an Artificial Fish Swarm algorithm to solve the problem of day-ahead scheduling of generation in a mix of Renewable Energy Sources, despatchable sources and storage. The utility function of hourly generation cost is considered for optimization along with various microgrid operational constraints. The performance of the algorithm is validated by applying to schedule generation in a microgrid in grid connected mode consisting of one wind turbine and one PV source as Renewable energy sources, one diesel generator and fuel cell as despatchable generators and a battery for storage. The scheduled generation of each generator, power exchange of storage source along with its state of charge are evaluated for optimum cost of generation.
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    Modified boost inverter topology for compensation of unbalanced and nonlinear loads in three phase system
    (01-12-2012)
    Panda, Soumya Kanta
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    Kollimalla, Sathish Kumar
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    This paper proposes a boost inverter topology to realize the reference currents generated by Instantaneous Symmetrical Component theory. The circuit topology and the switching pattern of the boost inverter boosts up a low voltage DC (e.g. photovoltaic panel or fuel cell) of a sustainable energy source to inject the required filter currents. The proposed boost inverter can perform load balancing, harmonic compensation and reactive power control while supplying real power to the grid. In a PV based boost inverter, PV panels of low output voltage can be connected in parallel, and eventually, a panel's defect or malfunction will not affect the operation of the whole system significantly. The boost inverter's switching are controlled by the Power Balance concept. This inverter topology is connected to the Point of Common Coupling (PCC) of the distribution system. The reference waveform generated from instantaneous symmetrical component theory are used further to generate instantaneous boost reference parameters. These boost reference parameters are then tracked by the boost converters to inject the desired filter currents into the corresponding phase. ©2012 IEEE.
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    Modulation-domain particle filter for template tracking
    (01-01-2008)
    Prakash, R. Senthil
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    Particle filters provide a robust framework for non-linear and non-Gaussian estimation problems. In this paper, we present a method to incorporate dominant modulation-domain (Amplitude Modulation-Frequency Modulation) features into particle filter based template tracking. The dominant AM-FM features capture the local texture structure of an image. Tracking is performed based on correlations of these AM-FM features. We propose an adaptive method that weights these correlations based on the significance of the features for tracking. The performance of the tracker is demonstrated on a few standard test sequences. © 2008 IEEE.
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    Applications of the single-port linear Thevenin theorem for focused and efficient analysis of a sub-network connected with a large existing pipe network
    An existing water distribution network (WDN) may need to be expanded by adding a sub-network for the newly developed areas. The size of the problem becomes larger when the stochastic nature of domestic demands, optimal design and layouts, control, and operation of various hydraulic components are considered. In this study, the single-port Thevenin theorem used in electrical circuits is applied to reduce a large WDN with its equivalent network consisting of a single source and a single pipe. The equivalent network is then attached to a sub-network for focused analysis. The accuracy and robustness of the proposed network reduction procedure are investigated on realistic WDNs for various sub-network demands using steady and extended period simulations. A simplified approach is also presented to achieve the same objective but constrained by the level of accuracy. Hydraulic engineers can use the proposed methodology as an efficient network reduction tool.
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    A resistive sensor readout circuit with intrinsic insensitivity to circuit parameters and its evaluation
    (01-07-2017)
    Sreenath, Vijayakumar
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    Semeerali, Koniyath
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    A novel readout circuit for interfacing single element resistive sensors is presented in this paper. The proposed scheme is based on a new relaxation oscillator (RO). The RO, along with a timer counter provides a digital output proportional to the resistance of the sensor. The output characteristic of most of the existing readout circuits for resistive sensors suffers from gain, offset, and nonlinearity errors. The sources of errors include various nonideal circuit parameters and their drift. The output of the proposed readout circuit has a special feature that it is not a function of the circuit parameters such as: 1) offset voltages of the opamps and comparators; 2) bias currents of the opamps and comparators; 3) gain of various units employed; 4) ON-resistance of the switches; 5) value or mismatch in the magnitudes of the reference voltages employed; 6) delay of the switches and comparator; 7) leakage current of the switch; and 8) slew rate of the opamp. Such a scheme will be useful for high accuracy measurements, even when the parameters 1)-8) may vary or drift, due to variation in the measurement environment. A prototype of the proposed readout scheme has been developed in the laboratory and the performance has been evaluated under various conditions. The output was found to be linear with a worst-case nonlinearity of 0.05%. Test results from a prototype developed show that the proposed scheme possesses all the features, described above, as expected.
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    Message from the program chairs
    (25-03-2011) ;
    Karthik, S.
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    Raghunathan, Anand
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    Modified widely linear filter for simultaneous multi-impairment compensation
    (01-01-2021)
    Yadav, Rekha
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    Venkatasubramani, Lakshmi Narayanan
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    We present a modified w idely l inear s ingle-tap b lind e qualizer f or t he joint multi-impairment compensation of polarization mixing, IQ Imbalance and transceiver phase noise, analyze its performance through simulation and experiments for 32Gbaud PM-16QAM transmission.
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    Distributed high temperature sensing using fiber bragg gratings
    In this paper we present a novel, practical approach for carrying out distributed high temperature sensing in boilers. We have demonstrated distributed high temperature sensing using fiber Bragg gratings encapsulated inside a rugged mechanical structure. The encapsulation is designed to not only protect the optical fiber from the harsh environment of the boiler, but also to scale the temperature down to a range over which the gratings are relatively stable. A key aspect of our work is the use of a Bayesian inference technique to retrieve the temperature outside the encapsulation within < 1°C accuracy based on the temperature measured by the fiber Bragg grating (FBG).
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    Design and development of a piezoelectrically actuated micropump for drug delivery application
    (01-01-2014)
    Eladi, Paul Braineard
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    Micropumps form the heart of several microfluidic systems like micro total analysis system (µTAS) and drug delivery devices, which have resulted from the advancement of silicon micromachining technology. Among the different available types of micropumps, valveless micropumps are better suited for biological applications as they do not have flow-rectifying valves and are less prone to clogging and wear. However, their main drawback is low thermodynamic efficiency. This can be improved if we have a better understanding of the effects of geometry on the performance. This forms one of the objectives of this work. This chapter describes the activity on the design and development of valveless micropumps. A numerical parametric study of the performance of valveless micropumps has been carried out and is presented to bring out the effects of different geometrical parameters. Based on these design approaches, silicon-based micropumps are fabricated and characterized. The performance of one of these micropumps is compared with designed value in this work.