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Articles 1951 - 1980 of 2359

Full-Text Articles in Engineering

Miniature Circularly Polarized Rectenna With Reduced Out-Of-Band Harmonics, Mohammod Ali, Guangli Yang, Roger A. Dougal Jan 2006

Miniature Circularly Polarized Rectenna With Reduced Out-Of-Band Harmonics, Mohammod Ali, Guangli Yang, Roger A. Dougal

Faculty Publications

Wireless embedded sensors are becoming increasingly important for many safety critical applications. Sensor batteries or capacitors must be charged as needed in order to achieve high data rate communications. A miniature circularly polarized rectenna operating at 5.5 GHz is introduced which, with the help of an integrated band-reject filter, reduces out-of-band harmonic emission significantly. The rectenna has a conversion efficiency of 74% with more than 50 dB out-of-band harmonic suppression at 11 GHz.

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Modeling Volume Changes In Porous Electrodes, Parthasarathy M. Gomadam, John W. Weidner Jan 2006

Modeling Volume Changes In Porous Electrodes, Parthasarathy M. Gomadam, John W. Weidner

Faculty Publications

A three-dimensional mathematical model is presented to describe volume changes in porous electrodes occurring during operation. Material conservation equations are used to derive governing relationships between electrode dimensions and porosity for deposition/precipitation, intercalation, and ionomer-based electrodes. By introducing a parameter, called the swelling coefficient, the relative magnitudes of the change in electrode dimensions and the change in porosity are determined. The swelling coefficient is design-dependent and measured experimentally for a given cell design. The model is general and forms a critical addition required to extend the existing porous electrode models to include volume change effects. For the special case of …

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Combinatorial Study Of Ni-Ti-Pt Ternary Metal Gate Electrodes On Hfo2 For The Advanced Gate Stack, K.-S. Chang, M. L. Green, J. Suehle, E. M. Vogel, H. Xiong, Jason R. Hattrick-Simpers, I. Takeuchi, O. Famodu, K. Ohmori, P. Ahmet, T. Chikyow, P. Majhi, B.-H. Lee, M. Gardner Jan 2006

Combinatorial Study Of Ni-Ti-Pt Ternary Metal Gate Electrodes On Hfo2 For The Advanced Gate Stack, K.-S. Chang, M. L. Green, J. Suehle, E. M. Vogel, H. Xiong, Jason R. Hattrick-Simpers, I. Takeuchi, O. Famodu, K. Ohmori, P. Ahmet, T. Chikyow, P. Majhi, B.-H. Lee, M. Gardner

Faculty Publications

The authors have fabricated combinatorial Ni–Ti–Pt ternary metal gate thin film libraries on HfO2 using magnetron co-sputtering to investigate flatband voltage shift (ΔVfb) , work function (Φm) , and leakage current density (JL) variations. A more negative ΔVfb is observed close to the Ti-rich corner than at the Ni- and Pt-rich corners, implying smaller Φm near the Ti-rich corners and higher Φm near the Ni- and Pt-rich corners. In addition, measured JL values can be explained consistently with the observed Φm variations. Combinatorial methodologies prove to be useful …

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An Experimental Investigation Of Guided Wave Propagation In Corrugated Plates Showing Stop Bands And Pass Bands, Tribikram Kundu, Sourav Banerjee, Kumar V. Jata Jan 2006

An Experimental Investigation Of Guided Wave Propagation In Corrugated Plates Showing Stop Bands And Pass Bands, Tribikram Kundu, Sourav Banerjee, Kumar V. Jata

Faculty Publications

Nonplanar surfaces are often encountered in engineering structures. In aerospace structures, periodically corrugated boundaries are formed by friction-stir-welding. In civil engineering structures, rebars used in reinforced concrete beams and slabs have periodic surface. Periodic structures are also being used to create desired acoustic band gaps. For health monitoring of these structures, a good understanding of the elastic wave propagation through such periodic structures is necessary. Although a number of research papers on the wave propagation in periodic structures are available in the literature, no one experimentally investigated the guided wave propagation through plates with periodic boundaries and compared the experimental …

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Elastic Wave Propagation In Sinusoidally Corrugated Waveguides, Sourav Banerjee, Tribikram Kundu Jan 2006

Elastic Wave Propagation In Sinusoidally Corrugated Waveguides, Sourav Banerjee, Tribikram Kundu

Faculty Publications

The ultrasonicwave propagation in sinusoidally corrugated waveguides is studied in this paper. Periodically corrugated waveguides are gaining popularity in the field of vibration control and for designing structures with desired acoustic band gaps. Currently only numerical method (Boundary Element Method or Finite Element Method) based packages (e.g., PZFlex) are in principle capable of modeling ultrasonic fields in complex structures with rapid change of curvatures at the interfaces and boundaries but no analyses have been reported. However, the packages are very CPU intensive; it requires a huge amount of computation memory and time for its execution. In this paper a new …

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Top-Down Structure And Device Fabrication Using In Situ Nanomachining, Xiaodong Li, Xinnan Wang, Qihua Xiong, Peter C. Eklund Dec 2005

Top-Down Structure And Device Fabrication Using In Situ Nanomachining, Xiaodong Li, Xinnan Wang, Qihua Xiong, Peter C. Eklund

Faculty Publications

We demonstrate the potential of an alternative tool for the fabrication of nanoscale structures and devices. A nanoindenter integrated with an atomic force microscope is shown to be a powerful machine tool for cutting precise length nanowires or nanobelts and for manipulating the shortened wires. We also demonstrate its utility in cutting grooves and fabricating dents (or periodic arrays of dents) in ZnSnanobelts. This approach permits the direct mechanical machining of nanodevices that are supported on a substrate without the inherent complications of e beam or photolithography.

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Effects Of Ebg Reflection Phase Profiles On The Input Impedance And Bandwidth Of Ultrathin Directional Dipoles, M. Faisal Abedin, Mohammod Ali Nov 2005

Effects Of Ebg Reflection Phase Profiles On The Input Impedance And Bandwidth Of Ultrathin Directional Dipoles, M. Faisal Abedin, Mohammod Ali

Faculty Publications

A comprehensive study of the effects of the reflection phase profiles on dipole antennas is presented with the ultimate objective of designing ultrathin printed dipoles (as thin as one hundredth of the wavelength). Dipole driving-point impedance and bandwidth are studied as function of various electromagnetic bandgap (EBG) reflection phase profiles. It is demonstrated that although many different reflection phase profiles can be generated for a certain antenna height, it is the profile that satisfies a specific range of reflection phase angles that is required to achieve good antenna performance. Such optimum EBG phase profiles are generated for a number of …

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Asynchronous Ds-Ss Cdma Random Spreading Code Correlation Statistics In The Presence Of Timing Error, David W. Matolak Nov 2005

Asynchronous Ds-Ss Cdma Random Spreading Code Correlation Statistics In The Presence Of Timing Error, David W. Matolak

Faculty Publications

We quantify the effect of timing tracking errors upon 2nd order correlation statistics of random binary spreading codes and, in so doing, fill a gap in the literature. Using a Gaussian model for timing tracking error, new expressions for autocorrelation statistics are derived. For crosscorrelations, we show that a zero mean Gaussian timing error has no effect upon 2nd order crosscorrelation statistics.

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Terahertz Studies Of The Dielectric Response And Second-Order Phonons In A Gase Crystal, B. L. Yu, F. Zeng, V. Kartazayev, R. R. Alfano, K. C. Mandal Oct 2005

Terahertz Studies Of The Dielectric Response And Second-Order Phonons In A Gase Crystal, B. L. Yu, F. Zeng, V. Kartazayev, R. R. Alfano, K. C. Mandal

Faculty Publications

No abstract provided.

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Mechanism Of Current Collapse Removal In Field-Plated Nitride Hfets, Alexei Koudymov, V. Adivarahan, Jinwei Yang, Grigory Simin, Asif Khan Oct 2005

Mechanism Of Current Collapse Removal In Field-Plated Nitride Hfets, Alexei Koudymov, V. Adivarahan, Jinwei Yang, Grigory Simin, Asif Khan

Faculty Publications

An experimental study of the mechanism of RF current collapse removal in high-power nitride-based HFETs is presented. The results show that the conductivity of the dielectric material under the field plate plays a crucial role in the current collapse removal. Identical geometry field plated HFETs differing only in the FP dielectric conductivity show varying degree of current collapse removal. Devices with semiconducting dielectric layers exhibit perfectly linear RF power - drain bias dependence with the output powers of 20 W/mm at 55 V drain bias with essentially no current collapse. A trapped charge discharging model is presented to explain the …

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Structure Of Human Thymidylate Synthase Under Low-Salt Conditions, Leslie L. Lovelace, Wladek Minor, Lukasz Lebioda Sep 2005

Structure Of Human Thymidylate Synthase Under Low-Salt Conditions, Leslie L. Lovelace, Wladek Minor, Lukasz Lebioda

Faculty Publications

Human thymidylate synthase, a target in cancer chemotherapy, was crystallized from PEG 3350 with 30 mM ammonium sulfate (AS) in the crystallization medium. The crystals are isomorphous with the high-salt crystals (~2.0 M AS) and the structure has been solved and refined (R = 22.6%, Rfree = 24.3%) at 1.8 Å resolution. The high- and low-AS-concentration structures are quite similar, with loop 181-197 is in the inactive conformation. Also, residues 95-106 and 129-135 (eukaryotic inserts region) show high mobility as assessed by poor electron density and high values of crystallographic temperature factors (residues 1-25 and 108-129 are disordered in both …

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Real-Space Electron Transfer In Iii-Nitride Metal-Oxide-Semiconductor-Heterojunction Structures, S. Saygi, A. Koudymov, V. Adivarahan, J. Yang, Grigory Simin, M. Asif Khan, J. Deng, R. Gaska, M. S. Shur Jul 2005

Real-Space Electron Transfer In Iii-Nitride Metal-Oxide-Semiconductor-Heterojunction Structures, S. Saygi, A. Koudymov, V. Adivarahan, J. Yang, Grigory Simin, M. Asif Khan, J. Deng, R. Gaska, M. S. Shur

Faculty Publications

The real-space transfer effect in a SiO2∕AlGaN∕GaN metal-oxide-semiconductor heterostructure (MOSH) from the two-dimensional (2D) electron gas at the heterointerface to the oxide-semiconductor interface has been demonstrated and explained. The effect occurs at high positive gate bias and manifests itself as an additional step in the capacitance-voltage (C‐V) characteristic. The real-space transfer effect limits the achievable maximum 2D electron gas density in the device channel. We show that in MOSH structures the maximum electron gas density exceeds up to two times that at the equilibrium (zero bias) condition. Correspondingly, a significant increase in the maximum channel current (up to …

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Mechanics Of Hydrogenated Amorphous Carbon Deposits From Electron-Beam-Induced Deposition Of Paraffin Precursor, W. Ding, D. A. Dikin, X. Chen, R. D. Piner, R. S. Ruoff, E. Zussman, X. Wang, Xiaodong Li Jul 2005

Mechanics Of Hydrogenated Amorphous Carbon Deposits From Electron-Beam-Induced Deposition Of Paraffin Precursor, W. Ding, D. A. Dikin, X. Chen, R. D. Piner, R. S. Ruoff, E. Zussman, X. Wang, Xiaodong Li

Faculty Publications

Many experiments on the mechanics of nanostructures require the creation of rigid clamps at specific locations. In this work, electron-beam-induced deposition(EBID) has been used to depositcarbonfilms that are similar to those that have recently been used for clamping nanostructures. The film deposition rate was accelerated by placing a paraffin source of hydrocarbon near the area where the EBIDdeposits were made. High-resolution transmission electron microscopy, electron-energy-loss spectroscopy, Raman spectroscopy, secondary-ion-mass spectrometry, and nanoindentation were used to characterize the chemical composition and the mechanics of the carbonaceous deposits. The typical EBIDdeposit was found to be hydrogenated amorphous carbon (a-C:H) having …

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Tb3+-Doped K Pb2Br5: Low-Energy Phonon Mid-Infrared Laser Crystal, U. N. Roy, R. H. Hawrami, Y. Cui, S. Morgan, A. Burger, K. C. Mandal, C. C. Noblitt, S. A. Speakman, K. Rademaker, S. A. Payne Apr 2005

Tb3+-Doped K Pb2Br5: Low-Energy Phonon Mid-Infrared Laser Crystal, U. N. Roy, R. H. Hawrami, Y. Cui, S. Morgan, A. Burger, K. C. Mandal, C. C. Noblitt, S. A. Speakman, K. Rademaker, S. A. Payne

Faculty Publications

No abstract provided.

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Nanomechanical Characterization Of Cavity Growth And Rupture In Hydrogen-Implanted Single-Crystal Batio3., Young-Bae Park, Patrick Nardi, Xiaodong Li, Harry A. Atwater Apr 2005

Nanomechanical Characterization Of Cavity Growth And Rupture In Hydrogen-Implanted Single-Crystal Batio3., Young-Bae Park, Patrick Nardi, Xiaodong Li, Harry A. Atwater

Faculty Publications

A thermodynamic model of cavitynucleation and growth in ion-implanted single-crystal BaTiO3 layer is proposed, and cavity formation is related to the measured mechanical properties to better understand hydrogen implantation-induced layer transfer processes for ferroelectric thin films. The critical radius for cavitynucleation was determined experimentally from blistering experiments performed under isochronal anneal conditions and was calculated using continuum mechanical models for deformation and fracture, together with thermodynamic models. Based on thermodynamic modeling, we suggest that cavitiesgrow toward the cracking criteria at a critical blister size whereupon gas is emitted from ruptured cavities. The main driving force for layer splitting is …

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Salient Closed Boundary Extraction With Ratio Contour, Song Wang, Toshiro Kubota, Jeffrey Mark Siskind, Jun Wang Apr 2005

Salient Closed Boundary Extraction With Ratio Contour, Song Wang, Toshiro Kubota, Jeffrey Mark Siskind, Jun Wang

Faculty Publications

We present ratio contour, a novel graph-based method for extracting salient closed boundaries from noisy images. This method operates on a set of boundary fragments that are produced by edge detection. Boundary extraction identifies a subset of these fragments and connects them sequentially to form a closed boundary with the largest saliency. We encode the Gestalt laws of proximity and continuity in a novel boundary-saliency measure based on the relative gap length and average curvature when connecting fragments to form a closed boundary. This new measure attempts to remove a possible bias toward short boundaries. We present a polynomial-time algorithm …

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Effect Of Tensile Offset Angles On Micro/Nanoscale Tensile Testing, Xiaodong Li, Xinnan Wang, Wei-Che Chang, Yuh-Jin Chao, Ming Chang Mar 2005

Effect Of Tensile Offset Angles On Micro/Nanoscale Tensile Testing, Xiaodong Li, Xinnan Wang, Wei-Che Chang, Yuh-Jin Chao, Ming Chang

Faculty Publications

For one-dimensional (1D) structures such as tubes, wires, and beams, tensile testing is a simple and reliable methodology for measuring their mechanical properties. The tensile offset angle effect on mechanical property measurement has long been ignored. In this study, theoretical and finite-element analysis(FEA) models for analyzing the tensile offset angle effect have been established. It is found that longitudinal stress decreases with increasing offset angles. The theoretically calculated elastic modulus relative errors reach 4.45% at the offset angle of 10°, whereas the experimentally measured elastic modulus relative errors are 45.4% at the offset angle of 15°. The difference in elastic …

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Design And Simulation Of A Permanent-Magnet Electromagnetic Aircraft Launcher, Dean Patterson, Antonello Monti, Charles W. Brice, Roger A. Dougal, Robert O. Pettus, Srinivas Dhulipala, Dilip Chandra Kovuri, Tiziana Bertoncelli Mar 2005

Design And Simulation Of A Permanent-Magnet Electromagnetic Aircraft Launcher, Dean Patterson, Antonello Monti, Charles W. Brice, Roger A. Dougal, Robert O. Pettus, Srinivas Dhulipala, Dilip Chandra Kovuri, Tiziana Bertoncelli

Faculty Publications

This paper describes the basic design, refinement, and verification using finite-element analysis, and operational simulation using the Virtual Test Bed, of a linear machine for an electromagnetic aircraft launcher, for the aircraft carrier of the future. Choices of basic machine format and procedures for determining basic dimensions are presented. A detailed design for a permanent-magnet version is presented, and wound-field coil and induction machine versions are briefly discussed. The long armature-short field geometry is justified, and in particular the impact of this geometry on the scale of the power electronic drive system is examined.

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Study And Design Of A Capacitively Coupled Polymeric Internal Antenna, Khan M.Z. Shams, Mohammod Ali Mar 2005

Study And Design Of A Capacitively Coupled Polymeric Internal Antenna, Khan M.Z. Shams, Mohammod Ali

Faculty Publications

A capacitively coupled polymeric internal antenna is introduced for Bluetooth or GPS applications. Such an antenna can be easily fabricated on a flexible film substrate and attached to the inside surface of the plastic housing of a portable wireless device; such as a PDA. The proposed antenna saves critical space on the printed circuit board (PCB) and eliminates the need for a vertical contact feed. Thus manufacturing is also simplified and cost is reduced. Practical examples of utilizing such a concept for Bluetooth (2.45 GHz) and GPS (1.575 GHz) applications are provided. The antenna system requires a small coupling plate …

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A Virtual Environment For Remote Testing Of Complex Systems, Loredana Cristaldi, Alessandro Ferrero, Antonello Monti, Ferdinanda Ponci, William Mckay, Roger A. Dougal Feb 2005

A Virtual Environment For Remote Testing Of Complex Systems, Loredana Cristaldi, Alessandro Ferrero, Antonello Monti, Ferdinanda Ponci, William Mckay, Roger A. Dougal

Faculty Publications

Complex systems, realized by integration of several components or subsystems, pose specific problems to simulation environments. It is, in fact, desirable to simulate the complex system altogether, and not component by component, since the operation of the single part depends on the surrounding system and an early verification can prevent damages and save time for modifications. The availability of detailed and validated models of the single parts is therefore critical. This task may be difficult to achieve. In fact, in industrial applications, where a system can be a mix of different devices produced by different manufacturers, the physical device may …

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A Miniaturized Hilbert Pifa For Dual-Band Mobile Wireless Applications, Mohammed Z. Azad, Mohammod Ali Jan 2005

A Miniaturized Hilbert Pifa For Dual-Band Mobile Wireless Applications, Mohammed Z. Azad, Mohammod Ali

Faculty Publications

A miniaturized planar inverted-F antenna (PIFa) is proposed for dual-band mobile phone application in the 900- and 1900-MHz bands. By employing a Hilbert geometry, an overall size reduction of 50% was achieved compared to a conventional rectangular PIFa. The proposed antenna can be easily printed on the inside surface of the plastic housing of a mobile phone or other wireless device. An experimental prototype of this miniature antenna was fabricated on 0.125 mm thick Duroid 5880 substrate. Measured results demonstrate dual-band characteristics with good radiation patterns.

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A New Circularly Polarized Rectenna For Wireless Power Transmission And Data Communication, Mohammod Ali, G. Yang, Roger A. Dougal Jan 2005

A New Circularly Polarized Rectenna For Wireless Power Transmission And Data Communication, Mohammod Ali, G. Yang, Roger A. Dougal

Faculty Publications

Small distributed wireless sensors are becoming very important in many aspects of our lives. While low data rate passive sensors operate with little energy there is a need for moderate to high data rate distributed sensors for infrastructure monitoring and other applications. Such sensors will require their batteries or onboard capacitors to be charged when depleted for proper operation. In this letter, we propose a circularly polarized (CP) microstrip patch antenna that can function as a WLAN antenna in the 5.15-5.35 GHz and as a rectenna at 5.5 GHz.

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Laser Induced Fluorescence Photobleaching Anemometer For Microfluidic Devices, Guiren Wang Jan 2005

Laser Induced Fluorescence Photobleaching Anemometer For Microfluidic Devices, Guiren Wang

Faculty Publications

We have developed a novel, non-intrusive fluid velocity measurement method based on photobleaching of a fluorescent dye for microfluidic devices. The residence time of thefluorescent dye in a laser beam depends on the flow velocity and approximately corresponds to the decaying time of the photobleaching of the dye in the laser beam. The residence time is inversely proportional to the flow velocity. The fluorescence intensity increases with the flow velocity due to the decrease of the residence time. A calibration curve between fluorescence intensity and known flow velocity should be obtained first. The calibration relationship is then used to calculate …

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Power Enhancement Of An Actively Controlled Battery/Ultracapacitor Hybrid, Lijun Gao, Roger A. Dougal, Shengyi Liu Jan 2005

Power Enhancement Of An Actively Controlled Battery/Ultracapacitor Hybrid, Lijun Gao, Roger A. Dougal, Shengyi Liu

Faculty Publications

An actively controlled battery/ultracapacitor hybrid has broad applications in pulse-operated power systems. A converter is used to actively control the power flow from a battery, to couple the battery to an ultracapacitor for power enhancement, and to deliver the power to a load efficiently. The experimental and simulation results show that the hybrid can achieve much greater specific power while reducing battery current and its internal loss. A specific example of the hybrid built from two size 18650 lithium-ion cells and two 100-F ultracapacitors achieved a peak power of 132 W which is a three-times improvement in peak power compared …

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Data Management And Visualization Of X-Ray Diffraction Spectra From Thin Film Ternary Composition Spreads, I. Takeuchi, C. J. Long, O. O. Famodu, M. Murakami, Jason R. Hattrick-Simpers, G. W. Rubloff, M. Stukowski, K. Rajan Jan 2005

Data Management And Visualization Of X-Ray Diffraction Spectra From Thin Film Ternary Composition Spreads, I. Takeuchi, C. J. Long, O. O. Famodu, M. Murakami, Jason R. Hattrick-Simpers, G. W. Rubloff, M. Stukowski, K. Rajan

Faculty Publications

We discuss techniques for managing and visualizing x-ray diffraction spectrum data for thin film composition spreads which map large fractions of ternary compositional phase diagrams. An in-house x-ray microdiffractometer is used to obtain spectra from over 500 different compositions on an individual spread. The MATLAB software is used to quickly organize the data and create various plots from which one can quickly grasp different information regarding structural and phase changes across the composition spreads. Such exercises are valuable in rapidly assessing the “overall” picture of the structural evolution across phase diagrams before focusing in on specific composition regions for detailed …

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Interphase Exchange Coupling In Fe/Sm-Co Bilayers With Gradient Fe Thickness, Ming-Hui Yu, Jason R. Hattrick-Simpers, Ichiro Takeuchi, Jing Li, Z. L. Wang, J. P. Liu, S. E. Lofland, Somdev Tyagi, J. W. Freeland, D. Giubertoni, M. Bersani, M. Anderle Jan 2005

Interphase Exchange Coupling In Fe/Sm-Co Bilayers With Gradient Fe Thickness, Ming-Hui Yu, Jason R. Hattrick-Simpers, Ichiro Takeuchi, Jing Li, Z. L. Wang, J. P. Liu, S. E. Lofland, Somdev Tyagi, J. W. Freeland, D. Giubertoni, M. Bersani, M. Anderle

Faculty Publications

We have fabricated Fe∕Sm–Co bilayers with gradient Fe thicknesses in order to systematically study the dependence of exchange coupling on the thickness of the Fe layer. The Fe layer was deposited at two different temperatures (150 and 300°C) to study the effect of deposition temperature on the exchange coupling. Magneto-optical Kerr effect and x-ray magnetic circular dichroism (XMCD) have been employed as nondestructive rapid characterization tools to map the magnetic properties of the gradient samples. Systematic enhancement in exchange coupling between the soft layer and the hard layer is observed as the soft layer thickness is decreased. Separate exchange couplings …

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Research Directions For Service-Oriented Multiagent Systems, Michael N. Huhns, Munindar P. Singh, Mark Burstein, Keith Decker, Edmund Durfee, Tim Finin, Les Gasser, Hrishikesh Goradia, Nick Jennings, Kiran Lakkaraju, Hideyuki Nakashima, H. Van Dyke Parunak, Jeffrey S. Rosenschein, Alicia Ruvinsky, Gita Sukthankar, Samarth Swarup, Katia Sycara, Milind Tambe, Tom Wagner, Laura Zavala, Mas Research Roadmap Project Jan 2005

Research Directions For Service-Oriented Multiagent Systems, Michael N. Huhns, Munindar P. Singh, Mark Burstein, Keith Decker, Edmund Durfee, Tim Finin, Les Gasser, Hrishikesh Goradia, Nick Jennings, Kiran Lakkaraju, Hideyuki Nakashima, H. Van Dyke Parunak, Jeffrey S. Rosenschein, Alicia Ruvinsky, Gita Sukthankar, Samarth Swarup, Katia Sycara, Milind Tambe, Tom Wagner, Laura Zavala, Mas Research Roadmap Project

Faculty Publications

Today's service-oriented systems realize many ideas from the research conducted a decade or so ago in multiagent systems. Because these two fields are so deeply connected, further advances in multiagent systems could feed into tomorrow's successful service-oriented computing approaches. This article describes a 15-year roadmap for service-oriented multiagent system research.

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A Semantic Web Services Architecture, Mark Burstein, Christoph Bussler, Michal Zaremba, Tim Finn, Michael N. Huhns, Massimo Paolucci, Amit P. Sheth, Stuart Williams Jan 2005

A Semantic Web Services Architecture, Mark Burstein, Christoph Bussler, Michal Zaremba, Tim Finn, Michael N. Huhns, Massimo Paolucci, Amit P. Sheth, Stuart Williams

Faculty Publications

The semantic Web services initiative architecture (SWSA) committee has created a set of architectural and protocol abstractions that serve as a foundation for semantic Web service technologies. This article summarizes the committee's findings, emphasizing its review of requirements gathered from several different environments. We also identify the scope and potential requirements for a semantic Web services architecture.

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Effects Of A Smaller Unit Cell Planar Ebg Structure On The Mutual Coupling Of A Printed Dipole Array, M. Faisal Abedin, Mohammod Ali Jan 2005

Effects Of A Smaller Unit Cell Planar Ebg Structure On The Mutual Coupling Of A Printed Dipole Array, M. Faisal Abedin, Mohammod Ali

Faculty Publications

A new smaller unit-cell planar electromagnetic bandgap (EBG) structure is proposed on low dielectric constant low-cost substrate (TMM: epsilon(r) = 4.5, thickness = 25 mils) that has a stopband frequency at around 4 GHz. The proposed structure when placed in between a two-element printed dipole array results in over 13-dB reduction in mutual coupling and a significant improvement in antenna return loss bandwidth and gain pattern.

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Flexible Multiobjective Control Of Power Converter In Active Hybrid Fuel Cell/Battery Power Sources, Zhenhua Jiang, Lijun Gao, Roger A. Dougal Jan 2005

Flexible Multiobjective Control Of Power Converter In Active Hybrid Fuel Cell/Battery Power Sources, Zhenhua Jiang, Lijun Gao, Roger A. Dougal

Faculty Publications

Hybrid power sources composed of fuel cells and secondary batteries can combine the high energy density of fuel cells with the high power density of batteries. A dc/dc power converter can be placed between the fuel cell and the battery to balance the power flow and greatly augment the peak output power. This paper presents a novel, flexible strategy for multiobjective control of the power converter in the hybrid power source. The control strategy is able to regulate the output current of the fuel cell and the charging current or voltage of the battery while limiting the discharging current of …

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