Physical Sciences and Mathematics Commons^™

Is The Ozone Hole Over Your Classroom?, Eugene Cordero

Faculty Publications, Meteorology and Climate Science

First year university science students are surveyed about their understanding of the ozone layer, ozone depletion and the effect of ozone depletion on Australia. Although students seem to understand the basic function of the ozone layer, over 65% of students incorrectly believe that the ozone hole is over Australia, and over 90% of students incorrectly believe that the ozone hole is present during the summer. Together these ideas seem to explain why nearly 75% of students blame the ozone hole for Australia’s high rate of skin cancer. Survey results also indicate that students seem confused about global warming, and the …

The Planetary Nebula Spectrograph: The Green Light For Galaxy Kinematics, N. G. Douglas, M. Arnaboldi, K. C. Freeman, K. Kuijken, M. R. Merrifield, Aaron J. Romanowsky, K. Taylor, M. Capaccioli, T. Axelrod, R. Gilmozzi, J. Hart, G. Bloxham, D. Jones

Faculty Publications

Planetary nebulae (PNe) are now well established as probes of galaxy dynamics and as standard candles in distance determinations. Motivated by the need to improve the efficiency of planetary nebulae searches and the speed with which their radial velocities are determined, a dedicated instrument—the Planetary Nebula Spectrograph, or PN.S—has been designed and commissioned at the 4.2 m William Herschel Telescope. The high optical efficiency of the spectrograph results in the detection of typically ∼150 PNe in galaxies at the distance of the Virgo Cluster in one night of observations. In the same observation, the radial velocities are obtained with an …

A Note On Computing The Generalized Inverse A^(2)_{T,S} Of A Matrix A, Xiezhang Li, Yimin Wei

Department of Mathematical Sciences Faculty Publications

The generalized inverse A T,S (2) of a matrix A is a {2}-inverse of A with the prescribed range T and null space S. A representation for the generalized inverse A T,S (2) has been recently developed with the condition σ (GA| T)⊂(0,∞), where G is a matrix with R(G)=T andN(G)=S. In this note, we remove the above condition. Three types of iterative methods for A T,S (2) are presented if σ(GA|T) is a subset of the open right half-plane and they are extensions of existing computational procedures of A T,S (2), including special cases such as the weighted Moore-Penrose …

On Inequalities And Partial Orderings For Weighted Reliability Measures, Broderick O. Oluyede

Department of Mathematical Sciences Faculty Publications

Inequalities, relations and partial ordering for weighted reliability measures are presented. Inequalities for Lévy distance measure for weighted distributions are obtained in terms of the parent distributions. Reliability inequalities and stability results are established for weighted distributions with monotone hazard and mean residual life functions.

A New Megalonychid Sloth From The Late Wisconsinan Of The Dominican Republic, Elizabeth Rega, Donald A. Mcfarlane, Joyce Lundberg, Keith Christenson

WM Keck Science Faculty Papers

An unusually well preserved skull, mandible, and indisputably associated post-cranial elements of new sloth, Acratocnus (Miocnus), were recovered from a cave in Jaragua National Park, Dominican Republic. The animal died lying in a rimstone pool and was rapidly coated with a thin calcite patina. We have documented a late Wisconsinan age for this specimen by inorganic 14C radiometric dating of the patina, with supporting data on the carbon systematics of the speleothems in this cave. This sloth is described as a new species on the basis of the distinctive morphology and relative size of cranial and mandibular features. We consider …

A Middle Pleistocene Age And Biogeography For The Extinct Rodent Megalomys Curazensis From Curaçao, Netherlands Antilles, Donald A. Mcfarlane, Joyce Lundberg

WM Keck Science Faculty Papers

The extinct oryzomyine rodent Megalomys curazensis has been known from abundant but fragmentary remains on the island of Curaçao since 1959. Here we demonstrate an age of 130 000 to 400 000 years before present based on geomorphological context, and propose a biogeographical model for the genus.

A Late Quaternary Paleoecological Record From Caves Of Southern Jamaica, West Indies, Donald A. Mcfarlane, Joyce Lundberg, A.G. Fincham

WM Keck Science Faculty Papers

Studies of an unusual and diverse system of caves in coastal southern Jamaica have yielded a paleoclimatic record associated with a fossil vertebrate record that provides useful insights into the poorly documented paleoecology of latest Wisconsinan and Holocene Jamaica. Episodes of significantly increased precipitation during the Holocene have left characteristic deposits of speleothems, and have supported both faunal and archaeological communities that were dependent on these mesic conditions. Deposits of fossil bat guano preserved in the caves provide a δ¹³C record of alternating mesic and xeric climatic episodes that supports the interpretation of the faunal and archaeological record.

Building Decision Tree Classifier On Private Data, Wenliang Du, Zhijun Zhan

Electrical Engineering and Computer Science - All Scholarship

This paper studies how to build a decision tree classifier under the following scenario: a database is vertically partitioned into two pieces, with one piece owned by Alice and the other piece owned by Bob. Alice and Bob want to build a decision tree classifier based on such a database, but due to the privacy constraints, neither of them wants to disclose their private pieces to the other party or to any third party. We present a protocol that allows Alice and Bob to conduct such a classifier building without having to compromise their privacy. Our protocol uses an untrusted …

A Practical Approach To Solve Secure Multi-Party Computation Problems, Wenliang Du, Zhijun Zhan

Electrical Engineering and Computer Science - All Scholarship

Secure Multi-party Computation (SMC) problems deal with the following situation: Two (or many) parties want to jointly perform a computation. Each party needs to contribute its private input to this computation, but no party should disclose its private inputs to the other parties, or to any third party. With the proliferation of the Internet, SMC problems becomes more and more important. So far no practical solution has emerged, largely because SMC studies have been focusing on zero information disclosure, an ideal security model that is expensive to achieve. Aiming at developing practical solutions to SMC problems, we propose a new …

Distributed And Multiprocessor Scheduling, Steven J. Chapin, Jon B, Weissman

Electrical Engineering and Computer Science - All Scholarship

This chapter discusses CPU scheduling in parallel and distributed systems. CPU scheduling is part of a broader class of resource allocation problems, and is probably the most carefully studied such problem. The main motivation for multiprocessor scheduling is the desire for increased speed in the execution of a workload. Parts of the workload, called tasks, can be spread across several processors and thus be executed more quickly than on a single processor. In this chapter, we will examine techniques for providing this facility. The scheduling problem for multiprocessor systems can be generally stated as \How can we execute a set …

Integration Of Naradabrokering And Audio/Video Conferencing As A Web Service, Hasan Bulut, Geoffrey C. Fox, Shrideep Pallickara, Ahmet Uyar, Wenjun Wu

Electrical Engineering and Computer Science - All Scholarship

Audio/Video Conferencing Systems need communication channels between their clients in order to transport RTP packets from one client to another. In this paper we investigate audio/video conferencing as a Web Service and the deployment of publish/subscribe systems in the context of audio/video conferencing systems. In this paper we use our research system NaradaBrokering, which supports both peer-to-peer and publish/subscribe paradigms, as a test bed to investigate these ideas. We also present results from our research system.

A Survey Of Various Frequency Domain Integral Equations For The Analysis Of Scattering From Three-Dimensional Dielectric Objects, Baek Ho Jung, T. K. Sarkar, Y.-S. Chung

Electrical Engineering and Computer Science - All Scholarship

In this paper, we present four different formulations for the analysis of electromagnetic scattering from arbitrarily shaped three-dimensional (3-D) homogeneous dielectric body in the frequency domain. The four integral equations treated here are the electric field integral equation (EFIE), the magnetic field integral equation (MFIE), the combined field integral equation (CFIE), and the PMCHW (Poggio, Miller, Chang, Harrington, and Wu) formulation. For the CFIE case, we propose eight separate formulations with different combinations of expansion and testing functions that result in sixteen different formulations of CFIE. One of the objectives of this paper is to illustrate that not all CFIE …

Interoperable Web Services For Computational Portals, Marlon Pierce, Geoffrey C. Fox, Choonhan Youn, Steve Mock, Kurt Mueller

Electrical Engineering and Computer Science - All Scholarship

Computational web portals are designed to simplify access to diverse sets of high performance computing resources, typically through an interface to computational Grid tools. An important shortcoming of these portals is their lack of interoperable and reusable services. This paper presents an overview of research efforts undertaken by our group to build interoperating portal services around a Web Services model. We present a comprehensive view of an interoperable portal architecture, beginning with core portal services that can be used to build Application Web Services, which in turn may be aggregated and managed through portlet containers.

Buffer Overflow And Format String Overflow Vulnerabilities, Kyung-Suk Lhee, Steve J. Chapin

Electrical Engineering and Computer Science - All Scholarship

This article surveys representative techniques of exploiting buffer overflow and format string overflow vulnerabilities and their currently available defensive measures. We also describe our buffer overflow detection technique that range checks the referenced buffers at run time. We augment executable files with type information of automatic buffers (local variables and parameters of functions) and static buffers (global variables in the data/bss section), and maintain the sizes of allocated heap buffers in order to detect an actual occurrence of buffer overflow. We describe a simple implementation with which we currently protect vulnerable copy functions in the C library.

Perspectives On The Evolution Of Simulation, Richard E. Nance, Robert G. Sargent

Electrical Engineering and Computer Science - All Scholarship

Simulation is introduced in terms of its different forms and uses, but the focus on discrete event modeling for systems analysis is dominant as it has been during the evolution of the technique within operations research and the management sciences. This evolutionary trace of over almost fifty years notes the importance of bidirectional influences with computer science, probability and statistics, and mathematics. No area within the scope of operations research and the management sciences has been affected more by advances in computing technology than simulation. This assertion is affirmed in the review of progress in those technical areas that collectively …

Integrated Ecological Economic Modeling Of The Patuxent River Watershed, Maryland, Robert Costanza, Alexey Voinov, Roelof Boumans, Thomas Maxwell, Ferdinando Villa, Lisa Wainger, Helena Voinov

Institute for Sustainable Solutions Publications and Presentations

Understanding the way regional landscapes operate, evolve, and change is a key area of research for ecosystem science. It is also essential to support the "placebased" management approach being advocated by the U.S. Environmental Protection Agency and other management agencies. We developed a spatially explicit, process-based model of the 2352 km2 Patuxent River watershed in Maryland to integrate data and knowledge over several spatial, temporal, and complexity scales, and to serve as an aid to regional management. In particular, the model addresses the effects of both the magnitude and spatial patterns of human settlements and agricultural practices on hydrology, plant …

Ilp Operators For Propositional Connectionist Networks, Miguel Angel Gutierrez-Naranjo, Pascal Hitzler

Computer Science and Engineering Faculty Publications

No abstract provided.

Closed Streamlines In Flow Visualization, Thomas Wischgoll

Computer Science and Engineering Faculty Publications

Vector Fields occur in many of the problems in science and engineering. In combustion processes for instance, vector fields describe the flow of the gas. This process can be enhanced using vector field visualization techniques. Also wind tunnel experiments can be analyzed. An example is the design of an air wing. The wing can be optimized to crate a smoother flow around it. Vector field visualization methods help the engineer to detect critical features of the flow. Consequently, feature detection methods gained great importance during the last years.

Topological methods are often used to visualize vector fields because they clearly …

Method Of The Quasilinearization For Nonlinear Impulsive Differential Equations With Linear Boundary Conditions, Paul W. Eloe, S. G. Hristova

Mathematics Faculty Publications

The method of quasilinearization for nonlinear impulsive differential equations with linear boundary conditions is studied. The boundary conditions include periodic boundary conditions. It is proved that the convergence is quadratic.

The Method Of Quasilinearization And A Three-Point Boundary Value Problem, Paul W. Eloe, Yang Gao

Mathematics Faculty Publications

The method of quasilinearization generates a monotone iteration scheme whose iterates converge quadratically to a unique solution of the problem at hand. In this paper, we apply the method to two families of three-point boundary value problems for second order ordinary differential equations: Linear boundary conditions and nonlinear boundary conditions are addressed independently. For linear boundary conditions, an appropriate Green's function is constructed. For nonlinear boundary conditions, we show that these nonlinearities can be addressed similarly to the nonlinearities in the differential equation.

Pricing And Product Mix Optimization In Freight Transportation, Michael F. Gorman

MIS/OM/DS Faculty Publications

We propose improved pricing and market mix can improve the profitability of the freight transportation provider through the reduction of equipment repositioning costs. We hypothesize that because of complexities surrounding pricing and equipment repositioning costing, existing pricing strategies in freight transportation fail to fully consider these costs. We test this hypothesis in an applied setting in which Monte Carlo simulation captures the stochasticity of market conditions inherent in the problem. We use a heuristic to improve the nondifferentiable, discontinuous objective function.

Our results from test cases show with high confidence that current prices are not optimal, as indicated by a …

Conversations Among Women In Mathematics (Program), University Of Dayton. Department Of Mathematics

Biennial Alumni Seminar

No abstract provided.

Cooling Atoms In An Optical Trap By Selective Parametric Excitation, Nicola Poli, Robert J. Brecha, Giacomo Roati, Giovanni Modugno

Physics Faculty Publications

We demonstrate the possibility of energy-selective removal of cold atoms from a tight optical trap by means of parametric excitation of the trap vibrational modes. Taking advantage of the anharmonicity of the trap potential, we either selectively remove the most energetic trapped atoms or excite those at the bottom of the trap by tuning the parametric modulation frequency. This process, which had been previously identified as a possible source of heating, also appears to be a robust way for forcing evaporative cooling in anharmonic traps.

A 0.5 Μm Thick Polysilicon Schottky Diode With Rectification Ratio Of 10^6, Elena A. Guliants, Chunhai Ji, Young J. Song, Wayne A. Anderson

Electrical and Computer Engineering Faculty Publications

Polycrystalline Si films, 0.5-mm thick, were obtained as a result of metal-induced growth by sputtering from a Si target on 25 nm thick Ni prelayers at 525 °C. Silicon grew heteroepitaxially on the NiSi2 layer formed due to the reaction between the sputtered Si atoms and Ni. Schottky diodes were fabricated on the Si films by deposition of a Schottky metal on the front surface of the film while Ni disilicide provided an intimate ohmic contact at the back. A Pd/n-Si diode using an n-Si film annealed for 2 h at 700 °C in forming gas demonstrated a rectification ratio …

Implementation Of A Si/Sic Hybrid Optically Controlled High-Power Switching Device, Prashant Bhadri, Kuntao Ye, Elena A. Guliants, Fred R. Beyette Jr.

Electrical and Computer Engineering Faculty Publications

The ever-increasing performance and economy of operation requirements placed on commercial and military transport aircraft are resulting in very complex systems. As a result, the use of fiber optic component technology has lead to high data throughput, immunity to EMI, reduced certification and maintenance costs and reduced weight features. In particular, in avionic systems, data integrity and high data rates are necessary for stable flight control. Fly-by-Light systems that use optical signals to actuate the flight control surfaces of an aircraft have been suggested as a solution to the EMI problem in avionic systems. Current fly-by-light systems are limited by …

Bronston And Burnside Members: Subdivision Of The St. Louis Limestone In South-Central Kentucky, Garland R. Dever Jr., Jack R. Moody

Report of Investigations--KGS

The St. Louis Limestone (Mississippian) of south-central Kentucky consists of two major lithologic units that herein are named, in ascending order, the Bronston Member and Burnside Member. Two other lithologic units occurring in the St. Louis Limestone and in correlative rocks of the Slade Formation (Mississippian), which extends from south-central into northeastern Kentucky, herein are named the Ringgold Bed and Big Sinking Bed.

The principal part of the St. Louis Member of the Slade Formation, which consists of Burnside lithologies, herein is renamed the Burnside Member of the Slade. This renaming addresses the problem associated with the previous use of …

Mapped Karst Groundwater Basins In The Lexington 30 X 60 Minute Quadrangle, James C. Currens, Randall L. Paylor, Joseph A. Ray

Map and Chart--KGS

This map shows karst groundwater basins in the Lexington quadrangle, determined primarily by groundwater tracer studies. It can be used to quickly identify the groundwater basins and springs to which a site may drain. Major springs and the relative size of their catchment areas can be evaluated for potential as water supplies. The map also serves as a geographic index to literature on karst groundwater in the area.

Decentralized Control For Coordinated Flow Of Multi-Agent Systems, Valentino Crespi, George Cybenko, Daniela Rus, Massimo Santini

Computer Science Technical Reports

This paper describes a distributed algorithm for coordinating the flow of a mass of vehicles approaching a highway exit or a tollbooth. We provide the problem formulation, a general methodology for distributed control and an instantiation of this methodology to the coordinated flow problem. We analyze our algorithm and provide experimental data.

Angular Range For Reflection Of P-Polarized Light At The Surface Of An Absorbing Medium With Reflectance Below That At Normal Incidence, R. M.A. Azzam, Ericson E. Ugbo

Electrical Engineering Faculty Publications

The range of incidence angle, 0 < φ < φ_e, over which p-polarized light is reflected at interfaces between transparent and absorbing media with reflectance below that at normal incidence is determined. Contours of constant φ_e in the complex plane of the relative dielectric constant ε are presented. A method for determining the real and imaginary parts of the complex refractive index, ε^1/2 = n + jk, which is based on measuring φ_e and the pseudo-Brewster angle φ_pB, is viable in the domain of fractional optical constants, n, k < 1.

Magnetic Measurements On Ga1-Xmnxs In High Fields Using The Cantilever Technique, Carl W. Maymi

All Volumes (2001-2008)

High field magnetic measurements have been taken on the III-VI Diluted Magnetic Semiconductor Ga1-xMnxS at the National High Magnetic Field Laboratory. This paper discusses the calibration of magnetic measurements made using the cantilever technique. It has been discovered that efficiency of cantilevers may decline over time, signaled by the onset of an oscillatory effect in the cantilever data.