MissouriUniversity of Science and Technology

Rolla, MO, United States

MissouriUniversity of Science and Technology

Rolla, MO, United States
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Mukherjee S.,MissouriUniversity of Science and Technology | Shamsi P.,MissouriUniversity of Science and Technology | Ferdowsi M.,MissouriUniversity of Science and Technology
IEEE Transactions on Power Electronics | Year: 2017

This paper analyzes the possibility of controlling the output voltage of a standalone single-phase inverter by directly controlling the output filter capacitor current without using a dedicated output voltage sensor. The plant modeling and controller design are presented. The proposed method depends on having the value of the output filter capacitance. A method to estimate the output filter capacitance is also presented. Rigorous analysis is done to show that the proposed sensorless scheme is largely insensitive to parameter variations and ensure that the output voltage is within specified regulations at utility level. It is also demonstrated in this paper that compared to the conventional voltage control scheme the proposed control scheme ensures an improved total harmonic distortion of the output voltage waveform. Experimental results presented validate the proposed scheme. © 1986-2012 IEEE.

Baddipadiga B.P.,MissouriUniversity of Science and Technology | Ferdowsi M.,MissouriUniversity of Science and Technology
IEEE Transactions on Power Electronics | Year: 2017

A high-voltage-gain dc-dc converter is introduced in this paper. The proposed converter resembles a two-phase interleaved boost converter on its input side while having a Dickson-charge-pump-based voltage multiplier (VM) on its output side. This converter offers continuous input current, which makes it more appealing for the integration of renewable sources like solar panels to a 400-V dc bus. Also, the proposed converter is capable of drawing power from either a single source or two independent sources. Furthermore, the VM used offers low voltage ratings for capacitors that potentially leads to size reduction. The converter design and component selection have been discussed in detail with supporting simulation results. A hardware prototype of the proposed converter with Vin = 20 and Vout = 400 V has been developed to validate the analytical results. © 1986-2012 IEEE.

Xu J.,MissouriUniversity of Science and Technology | Koledintseva M.Y.,MissouriUniversity of Science and Technology | Zhang Y.,Missouri University of Science and Technology | He Y.,Laird Technologies | And 4 more authors.
IEEE Transactions on Electromagnetic Compatibility | Year: 2010

A methodology to efficiently design products based on magneto-dielectric (ferrite) materials with desirable frequency responses that satisfy electromagnetic compatibility and signal integrity requirements over RF and microwave bands is presented here. This methodology is based on an analytical model of a composite magneto-dielectric material with both frequency-dispersive permittivity and permeability. A procedure for extracting complex permittivity and permeability of materials from experimental data is based on transmission line measurements. The genetic algorithm is applied for approximating both permittivity and permeability of materials by series of Debye frequency dependencies, so that they are represented as double-Debye materials (DDM). The DDM is incorporated in the finite-difference time-domain numerical codes by the auxiliary differential equation approach. © 2010 IEEE.

Khatiwada B.K.,Oklahoma State University | Hetayothin B.,MissouriUniversity of Science and Technology | Hetayothin B.,Chaffey College | Blum F.D.,Oklahoma State University
Macromolecular Symposia | Year: 2013

The behavior of an amorphous polymer, poly(methyl methacrylate) (PMMA), adsorbed on silica was studied using temperature-modulated differential scanning calorimetry (TMDSC). A two-component model, based on loosely-bound polymer with a glass transition temperature (Tg) (similar to that of the bulk polymer) and a tightly-bound polymer (with a Tg higher than that of the loosely-bound polymer) was used to interpret the thermograms. Increased sensitivity allowed the two transitions in the thermograms to be quantified much more accurately than in previous work. Linear regression analysis of the ratio of the area under two transitions with composition yielded the amount of tightly bound polymer, m″B = 1.21 +/- 0.21 mg PMMA/m 2silica. Two methods of analyzing the thermograms, fitting with a Gaussian-Lorentzian (GL) cross distribution function and perpendicular drop (PD) method, yielded similar results for the amount of tightly-bound polymer on the surfaces with the GL method having a statistically better fit to the model. The ratio of heat capacity increments of loosely bound and tightly bound polymer, ΔCpA/ΔCpB, around the glass transition, indicated the relative mobility of the two components. It was found that the ΔCpA was aboutthree times as large as that of ΔC pB suggesting that the tightly bound polymer had a much smaller change in mobility through glass transition region. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Luo T.,Institute for Infocomm Research | Das S.K.,MissouriUniversity of Science and Technology | Tan H.P.,Singapore Management University | Xia L.,Rensselaer Polytechnic Institute
ACM Transactions on Intelligent Systems and Technology | Year: 2016

Crowdsourcing can be modeled as a principal-agent problem in which the principal (crowdsourcer) desires to solicit a maximal contribution from a group of agents (participants) while agents are only motivated to act according to their own respective advantages. To reconcile this tension, we propose an all-pay auction approach to incentivize agents to act in the principal's interest, i.e., maximizing profit, while allowing agents to reap strictly positive utility. Our rationale for advocating all-pay auctions is based on two merits that we identify, namely all-pay auctions (i) compress the common, two-stage "bid-contribute" crowdsourcing process into a single "bid-cum-contribute" stage, and (ii) eliminate the risk of task nonfulfillment. In our proposed approach, we enhance all-pay auctions with two additional features: an adaptive prize and a general crowdsourcing environment. The prize or reward adapts itself as per a function of the unknown winning agent's contribution, and the environment or setting generally accommodates incomplete and asymmetric information, risk-averse (and risk-neutral) agents, and a stochastic (and deterministic) population. We analytically derive this all-pay auction-based mechanism and extensively evaluate it in comparison to classic and optimized mechanisms. The results demonstrate that our proposed approach remarkably outperforms its counterparts in terms of the principal's profit, agent's utility, and social welfare. © 2016 ACM.

Nanjari E.L.,University of Atacama | Golosinski T.S.,MissouriUniversity of Science and Technology
International Journal of Mining, Reclamation and Environment | Year: 2013

In an earlier study, the authors introduced the new algorithm that allows for a definition of open pit limits taking into consideration time value of money. This study presents further expansion of this algorithm that allows determining the optimum mining sequence and optimum width of pushbacks, in a manner that maximises the net present value (NPV) of a deposit. The algorithm combines dynamic programming and mining heuristic, and allows for incorporation of price vectors, costs, cut-off grades and other mine design parameters. Test runs of the algorithm conducted by the authors have led consistently to pits and mining sequences with higher NPV values than those generated using parametric techniques. © 2013 Copyright Taylor and Francis Group, LLC.

Jentschura U.D.,MissouriUniversity of Science and Technology | Jentschura U.D.,Mta Of Particle Physics Research Group | Nandori I.,Mta Of Particle Physics Research Group
European Physical Journal H | Year: 2014

It has been a notably elusive task to find a remotely sensical ansatz for a calculationof Sommerfeld’s electrodynamic fine-structure constant αQED ≈ 1 /137.036 based on first principles. However, this has not prevented anumber of researchers to invest considerable effort into the problem, despite theformidable challenges, and a number of attempts have been recorded in the literature.Here, we review a possible approach based on the quantum electrodynamic (QED)β function,and on algebraic identities relating αQED to invariant properties of“internal” symmetry groups, as well as attempts to relate the strength of theelectromagnetic interaction to the natural cutoff scale for other gauge theories.Conjectures based on both classical as well as quantum-field theoretical considerationsare discussed. We point out apparent strengths and weaknesses of the most prominentattempts that were recorded in the literature. This includes possible connections toscaling properties of the Einstein-Maxwell Lagrangian which describes gravitational andelectromagnetic interactions on curved space-times. Alternative approaches inspired bystring theory are also discussed. A conceivable variation of the fine-structure constantwith time would suggest a connection of αQED to global structures of theUniverse, which in turn are largely determined by gravitational interactions. © 2014, EDP Sciences and Springer-Verlag Berlin Heidelberg.

Schein L.B.,San Jose State University | Weiss D.S.,University of Rochester | Dunlap D.H.,University of New Mexico | Tyutnev A.,MoscowState Institute of Electronics and Mathematics | Parris P.E.,MissouriUniversity of Science and Technology
International Conference on Digital Printing Technologies | Year: 2011

Organic materials are being investigated for their electronic properties. Such materials are especially attractive for lightweight, flexible, and low-cost solar cells and light emitting devices, as well as transistors and electrophotographic photoreceptors. Yet, even after 40 years of work and a large database, the physics and chemistry that determines the electronic properties of organic materials are not well understood. This paper briefly summarizes data obtained from a new experimental variant of the time of flight (TOF) technique called TOF1a, which are compared to the predictions of a two-layer multiple trapping model (MTM) with an exponential distribution of traps. In TOF1a the charge generation depth is varied continuously, from surface generation to bulk generation, by varying the energy of the electron-beam excitation source. This produces systematic changes in the shape of the current transient that can be compared to the predictions of the two-layer MTM. We find that we can semi-quantitatively fit current transient data over the whole time range of the experiment, but only by using theoretical parameters that lie in a narrow range, the extent of which we quantify here. ©2011 Society for Imaging Science and Technology.

Restuccia F.,MissouriUniversity of Science and Technology | Das S.K.,MissouriUniversity of Science and Technology | Payton J.,University of North Carolina at Charlotte
ACM Transactions on Sensor Networks | Year: 2016

Participatory sensing is a powerful paradigm that takes advantage of smartphones to collect and analyze data beyond the scale of what was previously possible. Given that participatory sensing systems rely completely on the user's willingness to submit up-to-date and accurate information, it is paramount to effectively incentivize user's active and reliable participation. In this article, we survey existing literature on incentive mechanisms for participatory sensing systems. In particular, we present a taxonomy of existing incentive mechanisms for participatory sensing systems, which are subsequently discussed in depth by comparing and contrasting different approaches. Finally, we discuss an agenda of open research challenges in incentivizing users in participatory sensing. © 2016 ACM.

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