Digital Commons Network^™

Predicting The Readability Of Transparent Text, Lauren F. V. Scharff, Albert J. Ahumada Jr.

Faculty Publications

Will a simple global masking model based on image detection be successful at predicting the readability of transparent text? Text readability was measured for two types of transparent text: additive (as occurs in head-up displays) and multiplicative (which occurs in see-through liquid crystal display virtual reality displays). Text contrast and background texture were manipulated. Data from two previous experiments were also included (one using very low contrasts on plain backgrounds, and the other using higher-contrast opaque text on both plain and textured backgrounds). All variables influenced readability in at least an interactive manner. When there were background textures, the global …

The Anti-Monopoly Origins Of The Patent And Copyright Clause, Tyler T. Ochoa, Mark Rose

Faculty Publications

The British experience with patents and copyrights prior to 1787 is instructive as to the context within which the Framers drafted the Patent and Copyright Clause. The 1624 Statute of Monopolies, intended to curb royal abuse of monopoly privileges, restricted patents for new inventions to a specified term of years. The Stationers' Company, a Crown-chartered guild of London booksellers, continued to hold a monopoly on publishing, and to enforce censorship laws, until 1695. During this time, individual titles were treated as perpetual properties held by booksellers. In 1710, however, the Statute of Anne broke up these monopolies by imposing strict …

A Large-Area Ccd Camera For The Schmidt Telescope At The Venezuelan National Astronomical Observatory, C. Baltay, J. A. Snyder, P. Andrews, W. Emmet, B. Schaefer, J. Sinnott, C. Bailyn, P. Coppi, A. Oemler, C. N. Sabbey, S. Sofia, W. Van Altena, A. K. Vivas, C. Abad, A. Bongiovanni, C. Briceño, G. Bruzual, F. Della Prugna, G. Magris, Ge Sánchez, Gu Sánchez, H. Schenner, J. Stock, B. Adams, M. Gebhard, R. K. Honeycutt, J. Musser, A. Rengstorff, I. Ferrin, F. Fuenmayor, J. Hernandez, O. Naranjo, P. Rosenzweig

Faculty Publications

We have designed, constructed, and put into operation a large-area CCD camera that covers a large fraction of the image plane of the 1 m Schmidt telescope at Llano del Hato in Venezuela. The camera consists of 16 CCD devices arranged in a 4 × 4 mosaic covering 2.°3 × 3.°5 of sky. The CCDs are 2048 × 2048 LORAL devices with 15 μm pixels. The camera is optimized for drift-scan photometry and objective-prism spectroscopy. The design considerations, construction features, and performance parameters are described in the following paper.

Wave Packet Spreading: Temperature And Squeezing Effects With Applications To Quantum Measurement And Decoherence, G. W. Ford, R. F. O'Connell

Faculty Publications

A localized free particle is represented by a wave packet and its motion is discussed in most quantum mechanics textbooks. Implicit in these discussions is the assumption of zero temperature. We discuss how the effects of finite temperature and squeezing can be incorporated in an elementary manner. The results show how the introduction of simple tools and ideas can bring the reader into contact with topics at the frontiers of research in quantum mechanics. We discuss the standard quantum limit, which is of interest in the measurement of small forces, and decoherence of a mixed ("Schrödinger cat") state, which has …

Using A Computer Simulation To Teach Science Process Skills To College Biology And Elementary Majors, Aimée T. Lee, Rosalina V. Hairston, Rachel Thames, Tonya Lawrence, Sherry S. Herron

Faculty Publications

The Lateblight computer simulation (Arneson and Ticknor, 1990) has been implemented in the general biology laboratory and the science methods course for elementary teachers to reinforce the processes of science and to allow the students to engage, explore, explain, elaborate and evaluate the methods of building concepts in science. The students develop testable hypotheses and then use the program to run experiments and collect data. In addition, they research relevant background information and subsequently present their results in a poster during class.

Coordinated Target Assignment And Intercept For Unmanned Air Vehicles, Erik P. Anderson, Randal W. Beard, Michael A. Goodrich, Timothy W. Mclain

Faculty Publications

This paper presents an end-to-end solution to the cooperative control problem represented by the scenario where unmanned air vehicles (UAVs) are assigned to transition through known target locations in the presence of dynamic threats. The problem is decomposed into the subproblems of: 1) cooperative target assignment; 2) coordinated UAV intercept; 3) path planning; 4) feasible trajectory generation; and 5) asymptotic trajectory following. The design technique is based on a hierarchical approach to coordinated control. Simulation results are presented to demonstrate the effectiveness of the approach.

Properties Of Hadronic Final States In Diffractive Deep Inelastic Ep Scattering At Desy Hera, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Levi, A. Margotti, T. Massam, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli

Faculty Publications

Characteristics of the hadronic final state of diffractive deep inelastic scattering events ep→eXp were studied in the kinematic range 4X35GeV, 4

Polarization Effects In Photoluminescence Of C- And M-Plane Gan/Algan Multiple Quantum Wells, E. Kuokstis, C. Q. Chen, M. E. Gaevski, W. H. Sun, J. W. Yang, Grigory Simin, M. Asif Khan, H. P. Maruska, D. W. Hill, M. C. Chou, J. J. Gallagher, B. Chai

Faculty Publications

Polarizationeffects have been studied in GaN/AlGaN multiple quantum wells(MQWs) with different c-axis orientation by means of excitation-dependent photoluminescence(PL) analysis. Quantum structures were grown on [0001]-oriented sapphire substrates (C plane) and single-crystalline [11̄00]-oriented freestanding GaN (M plane) using the metalorganic chemical vapor deposition technique. Strong PL spectrum line blueshifts (up to 140 meV) which are correlated with the excitation intensity have been obtained for C-plane MQWs, whereas no shift has been observed for M-plane MQWs.Theoretical calculations and comparison with the PL data confirm that the built-in electric field for C-plane structures is much stronger than the field present for M-plane MQWs. …

A Quantum Rosetta Stone For Interferometry, Hwang Lee, Pieter Kok, Jonathan P. Dowling

Faculty Publications

Heisenberg-limited measurement protocols can be used to gain an increase in measurement precision over classical protocols. Such measurements can be implemented using, for example, optical Mach-Zehnder interferometers and Ramsey spectroscopes. We address the formal equivalence between the Mach-Zehnder interferometer, the Ramsey spectroscope and a generic quantum logic circuit. Based on this equivalence we introduce the 'quantum Rosetta stone', and we describe a projective-measurement scheme for generating the desired correlations between the interferometric input states in order to achieve Heisenberg-limited sensitivity. The Rosetta stone then tells us that the same method should work in atom spectroscopy.

Nitrogen Loading Into An Urban Estuary: Lake Pontchartrain (Louisiana, U.S.A.), R. Eugene Turner, Q. Dortch, Dubravko Justic, Erick M. Swenson

Faculty Publications

We constructed a nitrogen loading budget for the Lake Pontchartrain watershed located north of New Orleans, Louisiana (U.S.A.). Water quality measurements, discharge estimates, and literature values were used to establish the annual and seasonal variations in loading rates for total nitrogen and nitrate. The relatively stable annual loadings (million kg N) are about 10× that of the pre-settlement nitrogen loading, and come from atmosphere (1.3), the watershed (7.8), pumped urban runoff from New Orleans (1.0), and leakage through the Bonnet Carré flood control structure (0.5–0.9). Relatively minor additional amounts come from nitrogen fixation in the Lake. Occasional openings of the …

Deconstructing The General Plan Of Rehabilitation, John W. Lee

Faculty Publications

The general plan of rehabilitation doctrine provides that expenses incurred as part of a plan of general rehabilitation must be capitalized even though the same expenses incurred separately would be deductible as ordinary and necessary repairs. The emerging general standard after INDOPCO for current deduction of an expenditure with future benefits, the case with most repair/ improvement expenditures, is a balancing test: Whether the taxpayer ’s administrative and record keeping costs associated with capitalization outweigh the potential distortion of income from a current deduction of the future benefit expenditures. “Rough justice” rules for current deduction of future benefits expenditures, reflecting …

The Design And Evaluation Of Interactivities In A Digital Library, Muniram Budhu, Anita Coleman

Faculty Publications

The US National Science Foundation has established a program to create a National Science, Mathematics, Engineering and Technology Education Digital Library (NSDL). One of the subsidiary NSDL libraries under development is the National Civil Engineering Educational Resources Library (NCERL). The first phase of NCERL is the creation and collection of digital resources in three areas of civil engineering—geotechnical (soil), rock, and water engineering (GROW). The concept of interactivities guides the design, development, and evaluation efforts of the GROW digital collection. This article describes the salient features of GROW, defines and discusses interactivities as an emerging, integral part of teaching and …

Modeling The Multicast Address Allocation Problem, Daniel Zappala, Chris Gauthierdickey, Virginia Lo

Faculty Publications

To support IP multicast, domains must assign a unique multicast address to each application from a limited, globally-shared address space. We examine the performance of several classes of address allocation algorithms withln the context of the MASC architecture. This study is the first of its kind to model the generalized multicast address allocation problem and consider non-contiguous allocation algorithms. We find that prefix-based allocation outperforms our non-contiguous algorithm, despite the apparent advantages of non-contiguous allocation. We also verify the benefits of using worst-fit for new allocations.

Mapping The Mesoscale Interface Structure In Polycrystalline Materials, Brent L. Adams, C. L. Bauer, D. Casasent, A. Morawiec, S. Ozdemir, A. Talukder, Chialin T. Wu

Faculty Publications

This work was supported primarily by the MRSEC Program of the National Science Foundation under Award Numbers DMR-9632556 and DMR-0079996. A new experimental approach to the quantitative characterization of polycrystalline microstructure by scanning electron microscopy is described. Combining automated electron backscattering diffraction with conventional scanning contrast imaging and with calibrated serial sectioning, the new method (Mesoscale Interface Mapping System, MIMS) recovers precision estimates of the 3-dimensional idealized aggregate function G(x). This function embodies a description of lattice phase and orientation (limiting resolution ~ 1 degree) at each point x (limiting spatial resolution ~ 100 nanometers), and therefore contains a complete …

Distributions Of Nobel Metal Pd And Pt In Mesoporous Silica, J. Arbiol, A. Cabot, J. R. Morante, Fanglin Chen, Meilin Liu

Faculty Publications

Mesoporous silicananostructures have been synthesized and loaded with Pd and Pt catalytic noble metals. It is found that Pd forms small nanoclusters (3–5 nm) on the surface of the mesoporous structure whereas Pt impregnation results in the inclusion of Pt nanostructures within the silica hexagonal pores (from nanoclusters to nanowires). It is observed that these materials have high catalyticproperties for CO–CH₄CO–CH₄CO–CH₄ combustion, even in a thick film form. In particular, results indicate that the Pt and Pd dispersed in mesoporous silica are catalytically active as a selective filter for gas sensors.

Distributions Of Noble Metal Pd And Pt In Mesoporous Silica, J. Arbiol, A. Cabot, J. R. Morante, Fanglin Chen, Meilin Liu

Faculty Publications

Mesoporous silica nanostructures have been synthesized and loaded with Pd and Pt catalytic noble metals. It is found that Pd forms small nanoclusters (3–5 nm) on the surface of the mesoporous structure whereas Pt impregnation results in the inclusion of Pt nanostructures within the silica hexagonal pores (from nanoclusters to nanowires). It is observed that these materials have high catalytic properties for CO–CH4 combustion, even in a thick film form. In particular, results indicate that the Pt and Pd dispersed in mesoporous silica are catalytically active as a selective filter for gas sensors.

Horizon Occlusion Culling For Real-Time Rendering Of Hierarchical Terrains, Parris K. Egbert, Brandon Lloyd

Faculty Publications

We present a technique to perform occlusion culling for hierarchical terrains at run-time. The algorithm is simple to implement and requires minimal pre-processing and additional storage, yet leads to 2-4 times improvement in framerate for views with high degrees of occlusion. Our method is based on the well-known occlusion horizon algorithm. We show how to adapt the algorithm for use with hierarchical terrains. The occlusion horizon is constructed as the terrain is traversed in an approximate front to back ordering. Regions of the terrain are compared to the horizon to determine when they are completely occluded from the viewpoint. Culling …

Gan Homoepitaxy On Freestanding (11̄00) Oriented Gan Substrates, C. Q. Chen, M. E. Gaevski, W. H. Sun, E. Kuokstis, J. P. Zhang, R. S. Q. Fareed, H. M. Wang, J. W. Yang, Grigory Simin, M. A. Khan, Herbert-Paul Maruska, David W. Hill, Mitch M. C. Chou, Bruce Chai

Faculty Publications

We report homoepitaxialGaNgrowth on freestanding (11̄00) oriented (M-plane GaN) substrates using low-pressure metalorganic chemical vapor deposition.Scanning electron microscopy,atomic-force microscopy, and photoluminescence were used to study the influence of growth conditions such as the V/III molar ratio and temperature on the surface morphology and optical properties of the epilayers. Optimized growth conditions led to high quality (11̄00) oriented GaN epilayers with a smooth surface morphology and strong band-edge emission. These layers also exhibited strong room temperature stimulated emission under high intensity pulsed optical pumping. Since for III-N materials the (11̄00) crystal orientation is free from piezoelectric or spontaneous polarization electric fields, …

Interactional Digital Libraries: Uses And Users, Anita Coleman

Faculty Publications

No abstract provided.

Histone Methyltransferase Activity Of A Drosophila Polycomb Group Repressor Complex, Jürg Müller, Craig M. Hart, Nicole J. Francis, Marcus L. Vargas, Aditya Sengupta, Brigitte Wild, Ellen L. Miller, Michael B. O'Connor, Robert E. Kingston, Jeffrey A. Simon

Faculty Publications

Polycomb group (PcG) proteins maintain transcriptional repression during development, likely by creating repressive chromatin states. The Extra Sex Combs (ESC) and Enhancer of Zeste [E(Z)] proteins are partners in an essential PcG complex, but its full composition and biochemical activities are not known. A SET domain in E(Z) suggests this complex might methylate histones. We purified an ESC-E(Z) complex from Drosophila embryos and found four major subunits: ESC, E(Z), NURF-55, and the PcG repressor, SU(Z)12. A recombinant complex reconstituted from these four subunits methylates lysine-27 of histone H3. Mutations in the E(Z) SET domain disrupt methyltransferase activity in vitro and …

Low-Temperature Operation Of Alfan Single-Quantum-Well Light-Emitting Diodes With Deep Ultraviolet Emission At 285 Nm, A. Chitnis, R. Pachipulusu, V. Mandavilli, M. Shatalov, E. Kuokstis, J. P. Zhang, V. Adivarahan, S. Wu, Grigory Simin, M. Asif Khan

Faculty Publications

We present a study of the electrical and optical characteristics of 285 nm emission deep ultraviolet light-emitting diodes(LED) at temperatures from 10 to 300 K. At low bias, our data show the tunneling carrier transport to be the dominant conduction mechanism. The room-temperature performance is shown to be limited mostly by poor electron confinement in the active region and a pronounced deep level assisted recombination but not by the hole injection into the active region. At temperatures below 100 K, the electroluminescence peak intensity increases by more than one order of magnitude indicating that with a proper device design and …

Rf Rendez-Blue: Reducing Power And Inquiry Costs In Bluetooth-Enabled Mobile Systems, Eric S. Hall, Charles D. Knutson, David K. Vawdrey

Faculty Publications

In resource-limited mobile computing devices, Bluetooth wireless technology imposes a weighty burden due to inefficient power utilization and a sluggish device discovery process. Buttressing Bluetooth with Radio Frequency Identification (RFID) technology by performing an operation we call “Rendez-Blue” alleviates these limitations. In the Rendez-Blue process, an RFID signal is used as a cue to “wake-up” a sleeping Bluetooth radio. This ensures that the Bluetooth radio is active only when needed, significantly reducing power consumption. In addition, RFID is used to communicate Bluetooth device information, allowing the user to bypass the traditional 10.24-second discovery process.

Measurement Of Diffractive Production Of D*±(2010) Mesons In Deep-Inelastic Scattering At Hera, S. Chekanov, D. Krakauer, S. Magill, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli, A. Zichichi, G. Aghuzumtsyan, D. Bartsch, I. Brock

Faculty Publications

Diffractive production of D*±(2010) mesons in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 44.3 pb-1. Diffractive charm production is identified by the presence of a large rapidity gap in the final state of events in which a D*±(2010) meson is reconstructed in the decay channel D*+ → (D0 → K-π+)πs+ (+ charge conjugate). Differential cross sections when compared with theoretical predictions indicate the importance of gluons in such diffractive interactions. © 2002 Elsevier Science B.V. All rights reserved.

Experiments With Grow, Anita Coleman

Faculty Publications

No abstract provided.

Fluid Dynamics Of Flapping Aquatic Flight In The Bird Wrasse: Three-Dimensional Unsteady Computations With Fin Deformation, Ravi Ramamurti, William C. Sandberg, Rainald Lӧhner, Jeffrey A. Walker Phd, Mark W. Westneat

Faculty Publications

Many fishes that swim with the paired pectoral fins use fin-stroke parameters that produce thrust force from lift in a mechanism of underwater flight. These locomotor mechanisms are of interest to behavioral biologists, biomechanics researchers and engineers. In the. present study, we performed the first three-dimensional unsteady computations of fish swimming with oscillating and deforming fins. The objective of these computations was to investigate the fluid dynamics of force production associated with the flapping aquatic flight of the bird wrasse Gomphosus varius. For this computational work, we used the geometry of the wrasse and its pectoral fin, and previously measured …

Bluetooth: An Emerging Technology For Wireless Personal Area Networks, Eric S. Hall, Charles D. Knutson, David K. Vawdrey

Faculty Publications

Look under your desk or behind your computer. See that rat’s nest of wires and cables? Almost every cable or wire that tethers us to our devices (or our devices to one another) is unnecessary. Bluetooth wireless technology promises to reduce the cabling chaos that afflicts us all. Bluetooth is a recently developed technology that uses radio frequency (RF) transceivers to provide point-to-multipoint wireless connectivity within a personal space. Bluetooth was designed for both voice and data communication at low per-unit costs while consuming little power. To achieve the cost and power goals, Bluetooth limits connectivity to a sphere of …

Near-Band-Edge Photoluminescence Of Wurtzite-Type Aln, E. Kuokstis, J. Zhang, Q. Fareed, J. W. Yang, Grigory Simin, M. Asif Khan, R. Gaska, M. Shur, C. Rojo, L. Schowalter

Faculty Publications

Temperature-dependentphotoluminescence(PL)measurements were performed for A-plane and C-plane bulk AlN single crystals and epitaxial layers on sapphire. A strong near-band-edge (NBE) emission and deep-level luminescence were observed. At low excitations, the emission spectra are dominated by free and bound excitonic transitions and their LO-phonon replicas. At high excitations, the broadening and redshift of the NBE band is attributed to dense electron–hole plasma formation. The PL spectra differences of bulk single crystals and epilayers is explained by the electron–hole plasma expansion peculiarities.

Modeling The Thermal Behavior Of A Surface-Micromachined Linear-Displacement Thermomechanical Microactuator, Christian D. Lott, Timothy W. Mclain, John N. Harb, Larry L. Howell

Faculty Publications

Thermomechanical microactuators possess a number of desirable attributes including ease of fabrication and large force and displacement capabilities relative to other types of microactuators. These advantages provide motivation for improving thermomechanical microactuator designs that are more energy efficient and thus better suited for low-power applications. To this end, this paper describes the development and experimental validation of a finite-difference thermal model of a thermomechanical in-plane microactuator (TIM). Comparisons between the model and experimental results demonstrate the importance of including the temperature dependence of several parameters in the model. Strategies for reducing the power and energy requirements of the TIM were …

Evolution And Dynamics Of Tropical River Plumes In The Great Barrier Reef: An Integrated Remote Sensing And In Situ Study, D.M. Burrage, M.L. Heron, J.M. Hacker, T.C. Stieglitz, C.R. Steinberg, A. Prytz

Faculty Publications

[1] The short-lived but intense discharge of freshwater from tropical rivers into the Great Barrier Reef (GBR) Lagoon and the associated salinity reductions are a critical consideration in marine research and management of the ecologically sensitive GBR World Heritage Area. Salinity provides a unique tracer that gives clues to the origin of river-borne contaminants and allows the influences of storm-induced resuspension and river discharge on turbidity to be clearly distinguished. We describe a field investigation of the evolution and dynamics of the Herbert River plume in the central GBR. Its primary goals were to use an airborne salinity mapper and …

Investigating The Mechanism Of Acoustically Activated Uptake Of Drugs From Pluronic Micelles, Ghaleb A. Husseini, Christopher M. Runyan, William G. Pitt

Faculty Publications

Background

This paper examines the mechanism of ultrasonic enhanced drug delivery from Pluronic micelles. In previous publications by our group, fluorescently labeled Pluronic was shown to penetrate HL-60 cells with and without the action of ultrasound, while drug uptake was increased with the application of ultrasound.

Methods

In this study, the amount of uptake of two fluorescent probes, Lysosensor Green (a pH-sensitive probe) and Cell Tracker Orange CMTMR (a pH-independent probe), was measured in HL-60 and HeLa cells.

Results

The results of our experiments show that the increase in drug accumulation in the cells as a result of ultrasonication is …