Physical Sciences and Mathematics Commons^™

Is Parallel Programming Hard, And If So, Why?, Paul E. Mckenney, Maged M. Michael, Manish Gupta, Philip William Howard, Josh Triplett, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Of the 200+ parallel-programming languages and environments created in the 1990s, almost all are now defunct. Given that parallel systems are now well within the budget of the typical hobbyist or graduate student, it is not unreasonable to expect a new cohort in excess of several thousand parallel languages and environments to appear in the 2010s. If this expected new cohort is to have more practical impact than did its 1990s counterpart, a robust and widely applicable framework will be required that encompasses exactly what, if anything, is hard about parallel programming. This paper revisits the fundamental precepts of concurrent …

Tree Canopy Types Constrain Plant Distributions In Ponderosa Pine- Gambel Oak Forests, Northern Arizona, Scott R. Abella

Public Policy and Leadership Faculty Publications

Trees in many forests affect the soils and plants below their canopies. In current high-density southwestern ponderosa pine (Pinus ponderosa) forests, managers have opportunities to enhance multiple ecosystem values by manipulating tree density, distribution, and canopy cover through tree thinning. I performed a study in northern Arizona ponderosa pine-Gambel oak (Quercus gambelii) forests to measure the influences of tree canopy types on understory plant communities and soil properties. On ten 2.5-acre (1-ha) sites, I sampled five 43-ft2 (4-m2) plots below each of the following five canopy types: openings; single ponderosa pine; and Gambel oak single stems, dispersed clumps, and thickets. …

An Extended Dust Disk In A Spiral Galaxy : An Occulting Galaxy Pair In The Acs Nearby Galaxy Survey Treasury., Benne W. Holwerda, W. C. Keel, B. Williams, J. J. Dalcanton, R. S. De Jong

Faculty and Staff Scholarship

We present an analysis of an occulting galaxy pair, serendipitously discovered in the ACS Nearby Galaxy Survey Treasury observations of NGC 253 taken with the Hubble Space Telescope’s (HST) Advanced Camera for Surveys in F475W, F606W, and F814W (SDSS − g, broad V, and I). The foreground disk system (at z 0.06) shows a dusty disk much more extended than the starlight, with spiral lanes seen in extinction out to 1.5 R25, approximately 6 half-light radii. This pair is the first where extinction can be mapped reliably out to this distance from the center. The spiral arms of the extended …

Ultrafast Energy Transfer In Oligofluorene-Aluminum Bis(8-Hydroxyquinoline)Acetylacetone Coordination Polymers, Victor A. Montes, Grigory V. Zyryanov, Evgeny Danilov, Neeraj Agarwal, Manuel A. Palacios, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

Understanding the excited-state dynamics in conjugated systems can lead to their better utilization in optical sensors, organic photovoltaics (OPVs), and organic light-emitting diodes (OLEDs). We present the synthesis of self-assembled coordination polymers comprising two types of fluorescent moieties: discrete fluorene oligomers of a well-defined length (n = 1-9) connected via aluminum(III) bis(8-quinolinolate)acetylacetone joints. Due to their well-defined structure, these materials allowed for a detailed study of energy migration processes within the materials. Thus, femtosecond transient spectroscopy was used to study the ultrafast energy transfer from the oligofluorene to the quinolinolate moieties, which was found to proceed at a rate of …

Probing Single-Molecule Interfacial Electron Transfer Dynamics Of Porphyrin On Tio2 Nanoparticles, Yuanmin Wang, Xuefei Wang, Sujit Kumar Ghosh, H. Peter Lu

Chemistry Faculty Publications

Single-molecule interfacial electron transfer (ET) dynamics has been studied by using single-molecule fluorescence spectroscopy and microscopic imaging. For a single-molecule zinc-tetra (4-carboxyphenyl) porphyrin (ZnTCPP)/TiO2 nanoparticle system, the single-molecule fluorescence trajectories show strong fluctuation and blinking between bright and dark states. The intermittency and fluctuation of the single-molecule fluorescence are attributed to the variation of the reactivity of interfacial electron transfer. The nonexponential autocorrelation function and the power-law distribution of the probability density of dark times imply the dynamic and static inhomogeneities of the interfacial ET dynamics. On the basis of the power-law analysis, the variation of single-molecule interfacial ET reactivity …

The Functions And Values Of Fringing Salt Marshes In Northern New England, Usa, Pamela A. Morgan, David M. Burdick, Frederick T. Short

Environmental Studies Faculty Publications

Although large salt marshes of the northeastern United States have been studied extensively, very little is known about the smaller, fringing marshes in this area, despite the fact that they are a common habitat type. We compared the functions and values of five fringing salt marshes (FM) to those of five meadow marshes (MM) along the southern Maine/New Hampshire coast. Specifically we compared their primary production, soil organic matter content, plant diversity, sediment trapping ability and wave dampening properties. Also explored were the relationships between these functions and several physical characteristics at each site, including soil salinity, percent surface slope, …

Ua35/1 Doers & Deeds Vol. 7, No. 9, Wku Provost

WKU Administration Documents

Newsletter created by the WKU Provost & Vice President of Academic Affairs to highlight the activities of faculty, staff and alumni.

Spamed: A Spam Email Detection Approach Based On Phrase Similarity, Yiu-Kai D. Ng, Maria Soledad Pera

Faculty Publications

Emails are unquestionably one of the most popular communication media these days. Not only they are fast and reliable, but also free in general. Unfortunately, a significant number of emails received by email users on a daily basis are spam. This fact is annoying, since spam emails translate into a waste of user’s time in reviewing and deleting them. In addition, spam emails consume resources, such as storage, bandwidth, and computer processing time. Many attempts have been made in the past to eradicate spam emails; however, none has been proved highly effective. In this paper, we propose a spam-email detection …

Methods To Quantify Variable Importance: Implications For Theanalysis Of Noisy Ecological Data, Kim Murray, Mary M. Conner

Wildland Resources Faculty Publications

Determining the importance of independent variables is of practical relevance to ecologists and managers concerned with allocating limited resources to the management of natural systems. Although techniques that identify explanatory variables having the largest influence on the response variable are needed to design management actions effectively, the use of various indices to evaluate variable importance is poorly understood. Using Monte Carlo simulations, we compared six different indices commonly used to evaluate variable importance; zero-order correlations, partial correlations, semipartial correlations, standardized regression coefficients, Akaike weights, and independent effects. We simulated four scenarios to evaluate the indices under progressively more complex circumstances …

Desert Heat Island Study In Winter By Mobile Transect And Remote Sensing Techniques, Chen-Yi Sun, Anthony J. Brazel, Winston T. L. Chow, Brent C. Hedquist, Lela Prashad

Research Collection School of Social Sciences

A familiar problem in urban environments is the urban heat island (UHI), which potentially increases air conditioning demands, raise pollution levels, and could modify precipitation patterns. The magnitude and pattern of UHI effects have been major concerns of a lot of urban environment studies. Typically, research on UHI magnitudes in arid regions (such as Phoenix, AZ, USA) focuses on summer. UHI magnitudes in Phoenix (more than three million population) attain values in excess of 5°C. This study investigated the early winter period—a time when summer potential evapotranspiration >250 mm has diminished to 8.0°C, comparable to summertime UHI conditions. Through analysis …

Diffraction Of X-Waves From Multiple Rectangular Slits In An Opaque Screen, Ahmed El Saeed El Halawani

Archived Theses and Dissertations

No abstract provided.

Dynamically Error-Corrected Gates For Universal Quantum Computation, Kaveh Khodjasteh, Lorenza Viola

Dartmouth Scholarship

Scalable quantum computation in realistic devices requires that precise control can be implemented efficiently in the presence of decoherence and operational errors. We propose a general constructive procedure for designing robust unitary gates on an open quantum system without encoding or measurement overhead. Our results allow for a low-level err or correction strategy solely based on Hamiltonian engineering using realistic bounded-strength controls and may substantially reduce implementation requirements for fault-tolerant quantum computing architectures.

Programmer Friendly Refactoring Tools, Emerson Murphy-Hill

Dissertations and Theses

Tools that perform semi-automated refactoring are currently under-utilized by programmers. If more programmers adopted refactoring tools, software projects could make enormous productivity gains. However, as more advanced refactoring tools are designed, a great chasm widens between how the tools must be used and how programmers want to use them. This dissertation begins to bridge this chasm by exposing usability guidelines to direct the design of the next generation of programmer-friendly refactoring tools, so that refactoring tools fit the way programmers behave, not vice-versa.

Learning To Recognize Valuable Tags, Shilad Sen, Jesse Vig, John Riedl

Shilad Sen

No abstract provided.

All-Optical Control Of Nonlinear Focusing Of Laser Beams In Plasma Beat Wave Accelerator, Serguei Y. Kalmykov, Sunghwan A. Yi, Gennady Shvets

Serge Youri Kalmykov

Nonlinear focusing of a bi-color laser in plasma can be controlled by varying the difference frequency \Omega. The driven electron density perturbation forms a co-moving periodic focusing (de-focusing) channel if \Omega is below (above) the electron Langmuir frequency \omega_p. Hence, the beam focusing is enhanced for \Omega < \omega_p and is suppressed otherwise. In particular, a catastrophic relativistic self-focusing of a high-power laser beam can be prevented all-optically by a second, much weaker, co-propagating beam shifted in frequency by \Omega > \omega_p. A bi-envelope equation describing the early stage of the mutual de-focusing is derived and analyzed. Later stages, characterized by a well-developed electromagnetic cascade, are investigated numerically. Stable propagation of the over-critical laser pulse over several Rayleigh lengths is predicted. The non-resonant plasma beat wave (\Omega \not= \omega_p) can accelerate pre-injected electrons above …

Overview Of The Lambda-* Performance Reasoning Frameworks, Gabriel A. Moreno, Jeffery Hansen

Gabriel A. Moreno

Variations Of Ice Bed Coupling Beneath And Beyond Ice Streams: The Force Balance, Terence J. Hughes

Earth Science Faculty Scholarship

A geometrical force balance that links stresses to ice bed coupling along a flow band of an ice sheet was developed in 1988 for longitudinal tension in ice streams and published 4 years later. It remains a work in progress. Now gravitational forces balanced by forces producing tensile, compressive, basal shear, and side shear stresses are all linked to ice bed coupling by the floating fraction phi of ice that produces the concave surface of ice streams. These lead inexorably to a simple formula showing how phi varies along these flow bands where surface and bed topography are known: phi …

Terahertz Response Of Microfluidic-Jetted Fabricated 3d Flexible Metamaterials, Yew Li Hor

Dissertations

Conventional materials exhibit some restrictions on their electromagnetic properties. Especially in terahertz region, for example, materials that exhibit magnetic response are far less common in nature than materials that exhibit electric response. However, materials can be designed, namely artificial man-made metamaterials that exhibit electromagnetic properties that are not found in natural materials by adjusting, for example, the dielectric, magnetic or structural parameters of the constituent elements.

This dissertation demonstrates the use of new fabrication techniques to construct metamaterials in THz range via a material deposition system. The metamaterials are fabricated by stacking alternative layers with conventional designs such as single …

Voting In Group Support Systems : Theory, Implementation, And Results From An Exploratory Study, Kung-E Cheng

Dissertations

Group decision making is essential in organizations. Group Support Systems (GSS) can aide groups in making decisions by providing tools and process support. GSS is especially useful for geographically or temporally distributed groups. Researchers of GSS have pointed out that convergence processes are hard to accomplish in GSS. Voting tools in GSS can be a valuable asset in alleviating the difficulty of convergence processes because voting is a concise communication of individual preferences with a well defined procedure that is accepted by group members. In addition, voting results can serve as a group memory of the convergence processes. Field observations …

Collaborative Learning Utilizing A Domain-Based Shared Data Repository To Enhance Learning Outcomes, David J. Lubliner

Dissertations

A number of learning paradigms have postulated that knowledge formation is a dynamic process where learners actively construct a representation of concepts integrating information from multiple sources. Current teaching strategies utilize a compartmentalized approach where individual courses contain a small subset of the knowledge required for a discipline. The intent of this research is to provide a framework to integrate the components of a discipline into a cohesive whole and accelerate the integration of concepts enhancing the learning process. The components utilized to accomplish these goals include two new knowledge integration models; a Knowledge Weighting Model (KWM) and the Aggregate-Integrate-Master …

Loss Of Synchrony In An Inhibitory Network Of Type-I Oscillators, Myongkeun Oh

Dissertations

Synchronization of excitable cells coupled by reciprocal inhibition is a topic of significant interest due to the important role that inhibitory synaptic interaction plays in the generation and regulation of coherent rhythmic activity in a variety of neural systems. While recent work revealed the synchronizing influence of inhibitory coupling on the dynamics of many networks, it is known that strong coupling can destabilize phase-locked firing. Here we examine the loss of synchrony caused by an increase in inhibitory coupling in networks of type-I Morris-Lecar model oscillators, which is characterized by a period-doubling cascade and leads to mode-locked states with alternation …

Synchrotron Radiation-Based Characterization Of Gan- Based Mqw Structures And Strongly Correlated Materials, Sean M. O'Malley

Dissertations

The following dissertation applies synchrotron radiation-based characterization techniques to the fields of gallium nitrides, multiferroic manganites, and self-assembled nano-domain oxide films. These material systems were chosen due to their unusual properties and potential device applications, which have made them very attractive to the scientific community.

Synchrotron-based High Resolution X-ray Diffraction (HRXRD) was used to characterize the structural properties of GaN-based multiple quantum well (MQW) structures grown on trapezoidal shaped GaN ridges. Results where interpreted within the framework of vapor-phase diffusion and surface-migration effects during the metalorganic vapor phase epitaxial growth. The relatively short diffusion length of group- III precursors and …

The Italian Chamber Of Lords Sits On Listed Company Boards. An Empirical Analysis Of Italian Listed Company Boards From 1998 To 2006 - Presentation (Powerpoint Format), Paolo Santella, Carlo Drago, Andrea Polo

Paolo Santella

No abstract provided.

The Italian Chamber Of Lords Sits On Listed Company Boards. An Empirical Analysis Of Italian Listed Company Boards From 1998 To 2006 - Presentation (Powerpoint Format), Paolo Santella, Carlo Drago, Andrea Polo

Carlo Drago

No abstract provided.

Interagency Science And Research: Quarterly Progress Report, January 31, 2009, Margaret N. Rees

Interagency Science and Research Strategy

• The major focus this quarter has been on reviewing, interpreting, and incorporating the review comments for the SNAP Science and Research Strategy.
• A concept paper template has been designed for use in beta testing implementation of the SNAP Science and Research Strategy.
• Four Round 10 SNPLMA Conservation Initiative proposals were entered into the SNAP Science and Research peer review process.

Thermochemistry And Bond Energies Of Nitro -Alkanes, -Alkenes, -Carbonyls And Corresponding Nitrites, Surawee Snitsiriwat

Theses

Density functional and ab initio theory based calculations were performed on a series of nitro -alkanes, -alkenes, carbonyl and corresponding nitrites representing large-scale primary, secondary and tertiary nitro compounds and their radicals resulting from the loss of skeletal hydrogen atoms. Geometries, vibration frequencies and thermochemical properties, ΔfH°₂₉₈, S °(T) and C°p(T) (10K T 5 5000K) are calculated at the individual B3LYP/6-31G(d,p), B3LYP /6-31+G(2d,2p) and composite CBS-QB3 levels. Potential energy barriers for the internal rotations have been computed at the B3LYP/6-31G(d, p) level of theory and the lower barrier contributions are incorporated into entropy and heat capacity data. The …

Sustainable Site Remediation : A Life Cycle Assessment Approach, Harnoor Dhaliwal

Theses

Remediation of contaminated areas is often a resource-intensive activity that itself can create environmental burdens. Life cycle assessment (LCA) was used as a tool to examine the environmental impacts associated with remediation activities. A hypothetical contaminated site with five remediation alternatives was developed for this analysis. The results of Life cycle Impact Assessment (LCIA) indicated that greater site activity in terms of transportation, material and equipment use translated into higher environmental impacts.

A sensitivity analysis was performed to evaluate the environmental impacts further in different time horizons. The results showed that choice of time horizon can have a significant effect …

Road-Based Proactive Routing Protocols For Vehicular Networks, Neeraj Mahadevrao Rajgure

Theses

Vehicular networks are formed by vehicles communicating in an ad hoc manner or through cellular and IEEE 802.11 base stations. Routing in vehicular networks is challenging due to highly dynamic network topologies. Previous research done at the UbiNetS lab at NJIT has proposed the idea of Road-Based using Vehicular Traffic information (RBVT) routing. In RBVT, routes are sequences of road intersections, and geographical forwarding is used for sending packets between the intersections.

This thesis proposes two proactive RBVT protocols (RBVT-P and RBVT-PS) for city-based Vehicular Ad hoc NETworks (VANETs). RBVT-P is a completely distributed protocol that unicasts connectivity packets in …

Rna Secondary Structure Detection Programs With An Emphasis On Covariance Models, Justin Slotman

Theses

RNA secondary structure prediction requires a different approach from traditional alignment methods. Functional RNAs often have their secondary structure better conserved than their primary structure. Covariance models, probabilistic models that utilize stochastic-context-free grammars, are one approach. CMs allow for homology to be detected where purely sequence-based methods would fail. A background on CMs is given, as well as a background of the major classes of non-coding RNAs (ncRNAs). Comparisons are made between some CM-using tools (the Infernal suite and CMfinder) and some other RNA secondary structure tools (CARNAC, miRNAminer, Pfold, Mfold) as well as between Infernal and the primary alignment …

State Of The Antarctic And Southern Ocean Climate System, Paul Andrew Mayewski, M. P. Meredith, C. P. Summerhayes, J. Turner, A. Worby, P. J. Barrett, G. Casassa, Nancy A.N. Bertler, T. Bracegirdle, A. C. Naveira Garabato, D. Bromwich, H. Campbell, Gordon S. Hamilton, W. B. Lyons, Kirk A. Maasch, S. Aoki, C. Xiao, Tas Van Ommen

Earth Science Faculty Scholarship

This paper reviews developments in our understanding of the state of the Antarctic and Southern Ocean climate and its relation to the global climate system over the last few millennia. Climate over this and earlier periods has not been stable, as evidenced by the occurrence of abrupt changes in atmospheric circulation and temperature recorded in Antarctic ice core proxies for past climate. Two of the most prominent abrupt climate change events are characterized by intensification of the circumpolar westerlies (also known as the Southern Annular Mode) between similar to 6000 and 5000 years ago and since 1200-1000 years ago. Following …