Physical Sciences and Mathematics Commons^™

Notes From The Director, The Mcnair Team

McNair Scholars Research Journal

No abstract provided.

Combinatorial Approach To Planar Non-Colliding Robot Arm Motion Planning, Ileana Streinu

Computer Science: Faculty Publications

We propose a combinatorial approach to plan non-colliding motions for a polygonal bar-and-joint framework. Our approach yields very efficient deterministic algorithms for a category of robot arm motion planning problems with many degrees of freedom, where the known general roadmap techniques would give exponential complexity. It is based on a novel class of one-degree-of-freedom mechanisms induced by pseudo triangulations of planar point sets, for which we provide several equivalent characterization and exhibit rich combinatorial and rigidity theoretic properties. The main application is an efficient algorithm for the Carpenter's Rule Problem: convexify a simple bar-and-joint planar polygonal linkage using only non …

Reconstructing Ancient Egyptian Tombs, Hany Farid

Computer Science Technical Reports

From the pyramids of Giza to the tombs of Thebes (modern Luxor), ancient Egypt's glorious history has produced remarkable architecture. Sadly, the nearly four million yearly tourists have taken a heavy toll on many of these ancient structures. Of particular concern are many of the tombs located opposite to Luxor on the western bank of the Nile. Digital reconstruction of these tombs has the potential to help document and preserve these important historical structures. Photographing and reconstruction of these tombs poses new and unique problems that this paper begins to address. Techniques for removing image distortions, recovering 3-D shape, and …

Bayes Optimal Metasearch: A Probabilistic Model For Combining The Results Of Multiple Retrieval Systems, Javed A. Aslam, Mark Montague

Computer Science Technical Reports

We introduce a new, probabilistic model for combining the outputs of an arbitrary number of query retrieval systems. By gathering simple statistics on the average performance of a given set of query retrieval systems, we construct a Bayes optimal mechanism for combining the outputs of these systems. Our construction yields a metasearch strategy whose empirical performance nearly always exceeds the performance of any of the constituent systems. Our construction is also robust in the sense that if ``good'' and ``bad'' systems are combined, the performance of the composite is still on par with, or exceeds, that of the best constituent …

A Simple Surface Temperature Assimilation Scheme For Use In Land Surface Models, Venkataraman Lakshmi

Faculty Publications

This paper examines the utilization of surface temperature as a variable which can be assimilated in off-line land surface hydrological models. The connection between the surface temperature and evapotranspiration is utilized in making adjustments to the model-computed surface soil moisture. This adjustment is a function of the difference between the model-computed and the observed surface temperature. Comparisons between the model-computed and satellite-observed surface temperatures have been carried out. The assimilation of surface temperature is carried out twice a day (corresponding to the A.M. and P.M. overpass of the NOAA 10) over the Red-Arkansas basin in the southwestern United States (31°50′N-36°N, …

Simplified Calculation Of The Stability Matrix For Semiclassical Propagation, Sophya Garashchuk, John C. Light

Faculty Publications

We present a simple method of calculation of the stability (monodromy) matrix that enters the widely used semiclassical propagator of Herman and Kluk and almost all other semiclassical propagators. The method is based on the unitarity of classical propagation and does not involve any approximations. The number of auxiliary differential equations per trajectory scales linearly rather than quadratically with the system size. Just the first derivatives of the potential surface are needed. The method is illustrated on the collinear H[sub 3] system.

Three-Body Effects In The Fragmentation Of D2 By Slow, Highly-Charged Xenon, Robert D. Dubois, I. Ali, C. L. Cocke, C. R. Feeler, Ronald E. Olson

Physics Faculty Research & Creative Works

Highly charged xenon ions were used for fragmentation of D₂ and the corresponding kinematic data. five-body classical trajectory Monte Carlo calculations were presented. Two types of three body effects were identified for strong collisions. Interactions between the undissociated molecules and the dipole fields of the projectiles were also found compatible with the fragmentation picture. Quadrupole-like and higher multipole interactions were the result of the differences between the dissociating fragments and the projectile fields.

On The Persistence Of Small Regions Of Vorticity In The Protoplanetary Nebula, S. S. Davis, D. P. Sheehan, J. N. Cuzzi

Physics and Biophysics: Faculty Scholarship

The fate of small regions of vorticity in a barotropic model of the protoplanetary nebula is investigated over thousands of years using a finite difference model. It is found that the coherence time for a small island of vorticity depends on its size, strength, orientation, and radial location in the nebula. Anticyclonic vorticity retains its coherence for longer times than cyclonic vorticity due to favorable interactions with the Keplerian shear flow. Rossby waves are generated as a result of mean vorticity gradients across the disk. The two-dimensional nebula evolves from discrete vortices into an axisymmetric flow consisting of small-amplitude vortex …

Searches For Neutral Higgs Bosons In Quark-Antiquark Tau-Antitau Final States Using The Opal Detector At Lep, James Andrew Hocker '91

Doctoral Dissertations

Searches for neutral Higgs bosons have been performed with the OPAL detector at LEP. Approximately 170 /pb of e+e- collision data at a center-of-mass energy of 189 GeV have been used to search for the SM process e+e- to HZ as well as for the processes e+e- to hZ and e+e- to hA which occur in extended Higgs theories. The searches are sensitive to final states containing quarks and tau leptons, for which an artificial neural network for the identification of tau leptons was designed. The results have been combined with OPAL searches for other final states to obtain a …

Water Current, Volume 32, No. 6, December 2000

Water Current Newsletter

Lake Classification Project Could Establish National Water Quality Ranking Procedure
From the Director: Profiling the Individuals and Efforts That Comprise the Water Center; Faculty Members Named to Administrative Posts
Meet the Faculty: David M. Admiraal; John C. Holz
Quality-Assessed Groundwater Pesticide Data Available Online
Groundwater Guardians
Pesticides Discovered in Ogallala Aquifer According to Recent USGS Study
Spring Semester Water Resources Seminar: Social Sciences Affect on Allocation of Water and Natural Resources
Nominations Solicited for 2001 Nebraska Water Conference
Water News Briefs
Congratulations to Our Winners
Avoid Fall Irrigation
TGF National Award Recipients
Our New Look
Watch Us on the Web …

Surface Segregation And Restructuring Of Colossal-Magnetoresistant Manganese Perovskites La0.65Sr0.35Mno3, Hani Dulli, Peter A. Dowben, Sy-Hwang Liou, E. Ward Plummer

Department of Physics and Astronomy: Faculty Publications

We have investigated the surface chemical composition of crystalline films of La_0.65Sr_0.35MnO₃ by angle-resolved x-ray photoelectron spectroscopy. The surface composition was found to be significantly different from that of the bulk because of an appreciable Sr segregation. Furthermore, our study suggests that this Sr segregation has caused a major restructuring of the surface region characterized by the formation of a Ruddlesden-Popper phase (La,Sr)_n+1Mn_nO_3n+1 with n = 1. Segregation and restructuring in the surface region should be common in these doped perovskites and will have a profound impact on the electronic …

Allosteric Tuning Of Ruthenium 2,2’-Bipyridyl Luminescent Sensor Systems, Daqing Gan

Masters Theses

A series of new ruthenium bipyridyl crown supramolecular sensor systems containing two binding sites were synthesized. The crystal structure and photophysical properties of the developed sensor systems were thoroughly studied using x-ray, nuclear magnetic resonance and photoscopy methods. It turned out that the chelation of transition metal on the remote sites of the bipyridyl crown ligands greatly reduced the reactivity of the crown cavity. It is believed that the chelation of transition metal on the nitrogen atoms forces the bipyridyl function towards coplanarity and restricts the conformational freedom of the crown ring. The conformational rigidity in turn influences the binding …

Flow Near Submarine Canyons Driven By Constant Winds, Jun She, John M. Klinck

CCPO Publications

Circulation over coastal submarine canyons driven by constant upwelling or downwelling wind stress is simulated and analyzed with a primitive equation ocean model. Astoria Canyon, on the west coast of North America, is the focus of this study, and model results are consistent with most major features of mean canyon circulation observed in Astoria Canyon. Near-surface flow crosses over the canyon, while a closed cyclone occurs within the canyon. Upwelling prevails within the canyon and is larger than wind-driven upwelling along the adjacent shelf break. Water rises from depths reaching 300 m to the canyon rim and, subsequently, onto the …

Eustasy Determination From Borehole Data, Onshore New Jersey: New Boreholes And New Porosity Estimates, William Alan Van Sickel

Masters Theses

Backstripping analysis of detailed stratigraphic data from the Bass River and Ancora boreholes on the New Jersey Coastal Plain (Ocean Drilling Project Leg 17 4AX) was conducted to test and refine previous eustatic estimates (Kominz et al., 1998) and provide new Upper Cretaceous estimates. Porositydepth relationships required by the backstripping method were estimated to supplement those from the Cost B-2 well (Rhodehamel, 1977). Sand and mud porosity at shallow depths (<500 m) obtained here are higher than was seen at the Cost B-2 well.

The Bass River and Ancora boreholes targeted older sequences of the Upper Cretaceous to Paleocene. This new data allow for more accurate estimate of the magnitude of long-term sea-level …

Introduction: Symposium 2000: Water Rights And Watershed Management: Planning For The Future, Brian J. Perron, Sarah Richardson

William & Mary Environmental Law and Policy Review

No abstract provided.

Faint Radio Sources And Star Formation History, Deborah B. Haarsma, R. B. Partridge, R. A. Windhorst, E. A. Richards

University Faculty Publications and Creative Works

The centimeter-wave luminosity of local radio galaxies correlates well with their star formation rate. We extend this correlation to surveys of high-redshift radio sources to estimate the global star formation history. The star formation rate found from radio observations needs no correction for dust obscuration, unlike the values calculated from optical and ultraviolet data. Three deep radio surveys have provided catalogs of sources with nearly complete optical identifications and nearly 60% complete spectroscopic redshifts: the Hubble Deep Field and Flanking Fields at 12h + 62°, the SSA13 field at 13h + 42°, and the V15 field at 14h + 52°. …

Commuting Self-Adjoint Extensions Of Symmetric Operators Defined From The Partial Derivatives, Palle Jorgensen, Steen Pedersen

Mathematics and Statistics Faculty Publications

We consider the problem of finding commuting self-adjoint extensions of the partial derivatives {(1/i)(∂/∂x_j):j=1,...,d} with domain C^∞_c(Ω) where the self-adjointness is defined relative to L²(Ω), and Ω is a given open subset of R^d.

Estauarine And Coastal Marine Waters: Bioassessment And Biocriteria Technical Guidance, George R. Gibson, Michael L. Bowman, Jeroen Gerritsen, Blaine D. Snyder

Miscellaneous Articles, Papers, and Reports

(First paragraph) This technical guidance document is based on the concept that bioassessment and biocriteria programs for estuaries and near coastal waters are interrelated and critical components of comprehensive water resource protection and management. Understanding how estuarine ecosystems function and respond to human activity requires a holistic approach to protection and management that integrates biological assessments into the more traditional chemical and physical evaluations. Section 101 of the Clean Water Act requires federal and state agencies to “restore and maintain the chemical, physical, and biological integrity of the nation’s waters.”

An Efficient And Practical Scheme For Privacy Protection In E-Commerce Of Digital Goods, Feng Bao, Robert H. Deng, Peirong Feng

Research Collection School Of Computing and Information Systems

It is commonly acknowledged that customers’ privacy in electronic commerce should be well protected. The solutions may come not only from the ethics education and legislation, but also from cryptographic technologies. In this paper we propose and analyze a privacy protection scheme for e-commerce of digital goods. The scheme takes cryptography as its technical means to realize privacy protection for online customers. It is efficient in both computational cost and communication cost. It is very practical for real e-commerce systems compared with previous solutions. The cryptographic technique presented in this paper is rather simple. But the scheme has great application …

New Kinematic Models For Pacific‐North America Motion From 3 Ma To Present, Ii: Evidence For A “Baja California Shear Zone”, Timothy Dixon, Fred Farina, Charles Demets, Francisco Suarez-Vidal, John Fletcher, Bertha Marquez-Azua, M. Meghan Miller, Osvaldo Sanchez, Paul Umhoefer

All Faculty Scholarship for the College of the Sciences

We use new models for present‐day Pacific‐North America motion to evaluate the tectonics of offshore regions west of the Californias. Vandenburg in coastal Alta California moves at the Pacific plate velocity within uncertainties (∼1 mm/yr) after correcting for strain accumulation on the San Andreas and San Gregorio‐Hosgri faults with a model that includes a viscoelastic lower crust. Modeled and measured velocities at coastal sites in Baja California south of the Agua Blanca fault, a region that most previous models consider Pacific plate, differ by 3–8 mm/yr, with coastal sites moving slower that the Pacific plate. We interpret these discrepancies in …

Computational Geometry Column 40, Joseph O'Rourke

Computer Science: Faculty Publications

It has recently been established by Below, De Loera, and Richter-Gebert that finding a minimum size (or even just a small) triangulation of a convex polyhedron is NP-complete. Their 3SAT-reduction proof is discussed.

Ornithological Literature, Robert C. Beason

United States Department of Agriculture Wildlife Services: Staff Publications

BABY BIRD PORTRAITS BY GEORGE MIKSCH SUTTON.

COLLINS ILLUSTRATED CHECKLIST: BIRDS OF SOUTHERN AFRICA.

BIRDS OF AFRICA: FROM SEABIRDS TO SEED-EATERS. By Chris and Tilde Stuart.

HARMONY AND CONFLICT IN THE LIVING WORLD. By Alexander F. Skutch.

HOPE IS THE THING WITH FEATHERS. By Christopher Cokinos.

STURKIE’S AVIAN PHYSIOLOGY. Edited by G. Causey Whittow.

STARLINGS AND MYNAS. By Chris Feare and Adrian Craig.

BIRDING IN THE AMERICAN WEST. By Kevin J. Zimmer.

TAKING WING: ARCHAEOPTERYX AND THE EVOLUTION OF BIRD FLIGHT. By Pat Shipman.

Knowledge Discovery As An Aid To Organizational Creativity, Keng Siau

Research Collection School Of Computing and Information Systems

Computers can play an important role in the creative process. With the abundance of data and increasing speed of computers, creativity can now be stimulated and enhanced with knowledge mined from available data. The process is known as knowledge discovery or data mining. Knowledge discovery is the process of discovering interesting associations among data in the database. Users in the creativity process can feed on the discovered associations to generate creative solutions. The objective of this paper is to present knowledge discovery as an aid to creativity. The paper first presents the concept of knowledge discovery and then discusses the …

The Environmental Science Minor: A Disciplinary Approach To Interdisciplinary Studies With A Grounding In Undergraduate Research, Brian E. Bodenbender, Edward C. Hansen, Graham F. Peaslee, Jonathan W. Peterson

Faculty Publications

No abstract provided.

The Relative Age Of The Thin And Thick Galactic Disks, Wilson M. Liu, Brian Chaboyer

Dartmouth Scholarship

We determine the relative ages of the open cluster NGC 188 and selected Hipparcos field stars by isochrone fitting and compare them to the age of the thick-disk globular cluster 47 Tuc. The best-fit age for NGC 188 was determined to be 6.5 ± 1.0 Gyr. The solar-metallicity Hipparcos field stars yielded a slightly older thin-disk age, 7.5 ± 0.7 Gyr. Two slightly metal-poor ([Fe/H] = -0.22) field stars whose kinematic and orbital parameters indicate that they are members of the thin disk were found to have an age of 9.7 ± 0.6 Gyr. The age for 47 Tuc was …

The Use Of Benthic Macroinvertebrates By Rainbow Trout (Oncorhynchus Mykiss) In Lake Ogallala, Nebraska, Tyler J. Pearson

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.

Generalized Tcp Congestion Avoidance And Its Effect On Bandwidth Sharing And Variability, Archan Misra, John Baras, Teunis Ott

Research Collection School Of Computing and Information Systems

To model possible suggested changes in TCP window adaptation in response to randomized feedback, such as ECN (explicit congestion notification), we formulate a generalized version of the TCP congestion avoidance algorithm. We first consider multiple such generalized TCP flows sharing a bottleneck buffer under the assured service model and use a fixed point technique to obtain the mean window sizes and throughputs for the TCP flows, To further study how changes in the adaptation algorithm affect the variability in the throughput, we use an analytical-cum-numerical technique to derive the window distribution (and related statistics) of a single generalized flow under …

Simulation Of Instability Onset In A Gas Turbine, S. Fleeter, Elias N. Houstis, John R. Rice, C. Zhou

Department of Computer Science Technical Reports

No abstract provided.

A Proactive Approach To Distributed Dos Prevention Using Route-Based Packet Filtering, Kihong Park, Heejo Lee

Department of Computer Science Technical Reports

No abstract provided.

Impact Of Tile-Size Selection For Skewed Tiling, Yonghong Song, Zhiyuan Li

Department of Computer Science Technical Reports

No abstract provided.