Physical Sciences and Mathematics Commons^™

Magnetism In One Dimension: Fe On Cu(111), J. Shen, Ralph Skomski, M. Klaua, H. Jenniches, S. Sundar Manoharan, J. Kirschner

Ralph Skomski Publications

The magnetism and the morphology of one-dimensional Fe stripes on a Cu(111) vicinal surface with perpendicular magnetization are investigated. Scanning tunneling microscopy shows that the Fe stripes have nanometer width and are aligned in parallel along the [011] direction. From the magnetization curves it is inferred that the stripes exhibit a ferromagnetic behavior well below the nominal thickness of one monolayer. In contrast to two-dimensional films, the magnetization of the stripes is not only temperature but also time dependent. The dynamics of the stripes have been described by a micromagnetic Ising model with Glauber dynamics, yielding an effective anisotropy constant …

Simulation Of A Microdosimetry Problem: Behavior Of A Pseudorandom Series At A Low Probability, P. Meyer, J. E. Groetz, Robert Katz, M. Fromm, A. Chambaudet

Robert Katz Publications

The carcinogenic effects for low dose irradiations are not very well known. Estimations usually are made based on the effects observed at high doses that are then extrapolated to low doses. To estimate low dose effects, the ICRP (International Commission on Radiological Protection) uses a linear extrapolation matched with a dose-rate reduction factor equal to two. This proportionality of the effect and dose, even for the lowest doses and dose-rates, leads to two assumptions which must be questioned :
1. the efficiency of DNA repair in cells does not vary with the dose and the dose-rate,
2. when one single …

Optical Components For Wdm Lightwave Networks, Michael S. Borella, Jason P. Jue, Dhritiman Banerjee, Byrav Ramamurthy, Biswanath Mukherjee

School of Computing: Faculty Publications

Recently, there has been growing interest in developing optical fiber networks to support the increasing bandwidth demands of multimedia applications, such as video conferencing and World Wide Web browsing. One technique for accessing the huge bandwidth available in an optical fiber is wavelength-division multiplexing (WDM). Under WDM, the optical fiber bandwidth is divided into a number of nonoverlapping wavelength bands, each of which may be accessed at peak electronic rates by an end user. By utilizing WDM in optical networks, we can achieve link capacities on the order of 50 THz. The success of WDM networks depends heavily on the …

White Dwarfs In Globular Clusters: Hubble Space Telescope Observations Of M4, Harvey B. Richer, Matt A. Wood

Aerospace, Physics, and Space Science Faculty Publications

Using WFPC2 on the Hubble Space Telescope, we have isolated a sample of 258 white dwarfs (WDs) in the Galactic globular cluster M4. Fields at three radial distances from the cluster center were observed, and sizable WD populations were found in all three. The location of these WDs in the color-magnitude diagram, their mean mass of 0.51(±0.03) M⊙, and their luminosity function confirm basic tenets of stellar evolution theory and support the results from current WD cooling theory. The WDs are used to extend the cluster main-sequence mass function upward to stars that have already completed their nuclear evolution. The …

Reservoir Characterization Of Crystal Field And Analysis Of The Tow#1-3 Hd-1 Well, Montcalm County, Michigan, Heidi Wines

Masters Theses

The goal of this project was to characterize the Dundee reservoir of Crystal oil field using the newly drilled Tow #1-3 well data in conjunction with historical well records to evaluate heterogeneity of facies and their controls on oil production.

From the Tow# 1-3 HD-1 well, three major facies were identified in the reservoir. A non-fractured intertidal grainstone facies provides storage of fluids with its uniform permeability and excellent intercrystalline porosity. The supratidal fractured micrites and open marine fractured biomicrites are interbedded with the grainstone facies providing conduits for fluid migration between the facies. Facies are important controls on oil …

Multiple Representation For Understanding Data Structures, Biffah Hancies, Venky Shankararaman, Jose Munoz

Research Collection School Of Computing and Information Systems

In this paper an approach to enhance the learning of abstract computing concepts by novice students is presented. This approach is based on effective use of multiple visual representations, and it was applied within the domain of linear data structures: array, stack, queue and linked list. A prototype computer-based instructional system called MRUDS (Multiple Representation for Understanding Data Structures) was developed and evaluated. It was found from the evaluation that the three presentation modules namely, analogy, representation and algorithm contributed to the students' learning process, each contributing to and reinforcing the effect of the others.

Time-Efficient Maze Routing Algorithms On Reconfigurable Mesh Architectures, Fikret Ercal, H. C. Lee

Computer Science Faculty Research & Creative Works

The routing problem is one of the most widely studied problems in VLSI design. Maze-routing algorithms are used in VLSI routing and robot path planning. Efficiency of the parallel maze routing algorithms which were mostly based on C. Y. Lee's algorithm8is poor. In this paper, we propose time-efficient algorithms to solve the maze-routing problem on a reconfigurable mesh architecture. The constant-time algorithms presented include: (i) testing the existence of specific types of paths between two terminals, and (ii) finding an absolute shortest path (ASP) and a shortest duplex-path (SDP). In addition, a fast algorithm to find the single shortest path …

Geophysical Characterization Of A Jp-4 (Lnapl) Contaminated Site At The Wurtsmith, Air Force Base, Oscoda, Michigan, Kristina C. Sprietzer

Masters Theses

The detection of hydrocarbon contamination in the subsurface using geophysical techniques has been based on the known physical properties of high electrical resistivities (ρa) (low conductivities). However, geophysical field investigations at uncontrolled spill sites yield measurements of low resistivity (high conductivity). The purpose of this study is to test that in the natural environment some hydrocarbon spills (in the case of LNAPLs), can exhibit changes with time due to biodegradation, from electrically resistive to conductive. Since time is an important factor, this hypothesis was tested at a site where the time when a hydrocarbon release occurred is known and where …

Influence And Consensus In Group Decision Making Environment, Fiona Fui-Hoon Nah, Byungcho Kim

Research Collection School Of Computing and Information Systems

In this research, the effect of expert support on influence and consensus in group decision making is investigated. The results indicate that ESS support diminishes the group members' influence on the group judgment as well as the influence exerted by the most influential group member. On the other hand, explanations support provided by ESS increases consensus in group decision making.

Using Expert Support And Its Explanation Facilities For Group Decision Making, Fiona Fui-Hoon Nah, Izak Benbasat

Research Collection School Of Computing and Information Systems

As information technology is increasingly used to support group work, it becomes desirable to identify the types of computer-based decision aids that are beneficial for supporting group decision making. In a review of the decision support literature, Benbasat, DeSanctis and Nault (1993) point out the lack of empirical research in examining the use of expert support for group decision making. In our review of the literature in this respect, we identified only one case study (Sviokla, 1989), which examined the processes involved in the pre- and post-use of an expert support system (ESS) called PlanPower by a group of financial …

Theoretical Foundation For Relationship Construct In Information Modeling – Relation Element Theory, Keng Siau

Research Collection School Of Computing and Information Systems

Information modeling is a critical process in software development. One of the key constructs in information modeling is the relationship construct. Though commonly used, the relationship construct is poorly defined and lacks a strong theoretical foundation. The objectives of this research are to define and classify the various relationships based on a theory in linguistic known as the relation element theory. This paper describes the theory, relates the theory to the relationship construct, and discusses the implication of the theory on the relationship construct.

An Improved Analytical Model For Wormhole Routed Networks With Application To Butterfly Fat-Trees, Ronald I. Greenberg, Lee Guan

Computer Science: Faculty Publications and Other Works

A performance model for wormhole routed interconnection networks is presented and applied to the butterfly fat-tree network. Experimental results agree very closely over a wide range of load rate. Novel aspects of the model, leading to accurate and simple performance predictions, include (1) use of multiple-server queues, and (2) a general method of correcting queuing results based on Poisson arrivals to apply to wormhole routing. These ideas can also be applied to other networks.

Breakdown Of The Iron Passive Layer By Use Of The Scanning Electrochemical Microscope, David O. Wipf, John W. Still

Publications

The scanning electrochemical microscope (SECM) is used to generate localized corrosion at passivating iron surfaces by using the tip to generate Cl^– ions. Use of the SECM allows the rapid establishment of a locally aggressive chemical environment at a pre-selected site on the iron surface. The susceptibility for passive-layer breakdown and corrosion initiation was examined as a function of the time between the start of the passive-layer growth and the formation of Cl^- ions. The breakdown of the passive-layer was found to depend strongly on the passivation potential and the site of Cl^- formation on the iron …

Using The Quantum Computer To Break Elliptic Curve Cryptosystems, Jodie Eicher, Yaw Opoku

Department of Math & Statistics Technical Report Series

This article gives an introduction to Elliptic Curve Cryptography and Quantum Computing. It includes an analysis of Peter Shor’s algorithm for the quantum computer breakdown of Discrete Log Cryptosystems and an analog to Shor’s algorithm for Elliptic Curve Cryptosystems. An extended example is included which illustrates how this modified Shor’s algorithm will work.

Toward A Molecular Theory Of Vapor-Phase Nucleation. V. Self-Consistency In The Decoupled Dimer Limit, K.J. Oh, Xiao Cheng Zeng, H. Reiss

Xiao Cheng Zeng Publications

The previous papers of this series introduced a molecular i / υ cluster theory of vapor phase nucleation. This theory differs from most conventional ones in that the cluster (due to fluctuation) is not only characterized by its number of particles i but also by a spherical volume υ. Thus the free energy of formation of the cluster is not merely a one-dimensional function of the number of particles i but a two-dimensional function of both i and v (i.e., it is a free energy surface). In the first stage of this development (Refs. 1–3) the theory is based on …

Magneto-Optic Trapping Of Β-Decaying 38km, 37k From An On-Line Isotope Separator, J. A. Behr, A. Gorelov, T. Swanson, O. Hausser, K. P. Jackson, M. Trinczek, U. Giesen, J. M. D'Auria, R. Hardy, T. Wilson, P. Choboter, F, Leblond, L. Buchmann, M. Dombsky, C. D.P. Levy, G. Roy, B. A. Brown, J. Dilling

Mathematics

A magneto-optic trap (MOT) can provide a well-polarized, backing-free, localized source of radioactive atoms for β-decay experiments. We have trapped approximately 6000 atoms of ³⁸K^m ( t_1/2 = 0.925s) and 2000 atoms of ³⁷K (1.226 s) produced at the TRIUMF on-line separator TISOL in a vapor-cell MOT. We have measured optical isotope shifts and deduced the nuclear charge radii, which show an unusual lack of change at the neutron number N = 20 shell closure. Plans include a search for scalar contributions to the β⁺- ν correlation in the 0⁺→0⁺ decay …

Nested Hadamard Difference Sets, James A. Davis, Jonathan Jedwab

Department of Math & Statistics Faculty Publications

A Hadamard difference set (HDS) has the parameters (4N², 2N² − N, N² − N). In the abelian case it is equivalent to a perfect binary array, which is a multidimensional matrix with elements ±1 such that all out-of-phase periodic autocorrelation coefficients are zero. We show that if a group of the form H × Z²_p^r contains a (hp^2r, √hp^r(2√hp^r − 1), √hp^r(√hp^r − 1)) HDS (HDS), p a prime not dividing |H| …

Impedance Spectroscopy Of Bilayer Lipid Membranes And Tio₂ Based Solar Cells, Uwe Hermes

Dissertations and Theses

It has been proposed in the literature that a novel class of biosensors can be based on a bimolecular layer of lipids supported on one side by a metallic surface. In order to estimate the potential of this system for the design of membrane sensors, we have studied properties of a two-electrode system consisting of a teflon insulated metallic wire and a Ag/AgCl electrode, both immersed in KCl solution. The lipid bimolecular layer was formed on the metal surface of the cut teflon insulated wire. The electrical conductivity properties of such a device were studied in the frequency range 20 …

Vacuum Structure Of Two-Dimensional Gauge Theories On The Light Front, Gary Mccartor, David G. Robertson, Stephen S. Pinksy

Physics Faculty Scholarship

We discuss the problem of vacuum structure in light-front field theory in the context of (1+1)-dimensional gauge theories. We begin by reviewing the known light-front solution of the Schwinger model, highlighting the issues that are relevant for reproducing the θ structure of the vacuum. The most important of these are the need to introduce degrees of freedom initialized on two different null planes, the proper incorporation of gauge field zero modes when periodicity conditions are used to regulate the infrared, and the importance of carefully regulating singular operator products in a gauge-invariant way. We then consider SU(2) Yang-Mills theory in …

Multimedia Data Analysis Using Imagetcl (Extended Version), Charles B. Owen, Fillia Makedon

Computer Science Technical Reports

ImageTcl is an new system which provides powerful Tcl/Tk based media scripting capabilities similar to those of the ViewSystem and Rivl in a unique environment that allows rapid prototyping and development of new components in the C++ language. Powerful user tools automate the creation of new components as well as the addition of new data types and file formats. Applications using ImageTcl at the Dartmouth Experimental Visualization Laboratory (DEVLAB) include multiple stream media data analysis, automatic image annotation, and image sequence motion analysis. ImageTcl combines the high speed of compiled languages with the testing and parameterization advantages of scripting languages.

Multiple Media Stream Data Analysis: Theory And Applications (Extended Version), Charles B. Owen, Fillia Makedon

Computer Science Technical Reports

This paper presents a new model for multiple media stream data analysis as well as descriptions of some applications of this model in development at Dartmouth College. This model formalizes the exploitation of correlations between multiple, potentially heterogeneous, media streams in support of numerous application areas. The goal of the technique is to determine temporal and spatial alignments which optimize a correlation function and indicate commonality and synchronization between media streams. It also provides a framework for comparison of media in unrelated domains. Applications such as text-to-speech alignment, functional magnetic resonance imaging, speaker localization, and degraded media realignment are described.

Long Dormancy, Low Slip Rate, And Similar Slip‐Per‐Event For The Emerson Fault, Eastern California Shear Zone, Charles M. Rubin, Kerry Sieh

All Faculty Scholarship for the College of the Sciences

Excavations in a playa along the 1992 rupture of the Emerson fault reveal evidence of two paleoseismic events, with only one large prehistoric rupture in the past 15 millennia. Accelerator mass spectrometer radiocarbon ages of charcoal from playa sediments and from fault‐scarp colluvium directly beneath the playa beds indicate that the last large prehistoric slip event occurred about 9000 ka. Trench‐wall exposures revealed clear evidence of at least one pre‐9 ka rupture at the playa site. The event horizon of this earthquake is between two pedogenic carbonate layers that have radiocarbon ages of 14.8 ka and 24.1 ka, implying that …

Detection Of Volcanic Ash Clouds From Nimbus 7/Total Ozone Mapping Spectrometer, C. J. Seftor, N. C. Hsu, J. R. Herman, P. K. Bhartia, O. Torres, William I. Rose, David J. Schneider, N. Krotkov

Department of Geological and Mining Engineering and Sciences Publications

Measured radiances from the Version 7 reprocessing of the Nimbus 7/total ozone mapping spectrometer (TOMS) 340- and 380-nm channels are used to detect absorbing particulates injected into the atmosphere after the El Chichon eruption on April 4, 1982. It is shown that while the single-channel reflectivity determined from the 380-nm channel is able to detect clouds and haze composed of nonabsorbing aerosols, the spectral contrast between the 340- and 380-nm channels is sensitive to absorbing particulates such as volcanic ash, desert dust, or smoke from biomass burning. In this paper the spectral contrast between these two channels is used to …

Bern Porter International: Volume 1 Number 1 (Summer, 1997), Bern Porter, Sheila Holtz, Natasha Bernstein

Newsletters

A Literary Newspaper

Featuring the Bern Porter International mission statement with an introduction to the Institute of Advanced Thinking and Porter's literary philosophy.

An Analysis Of Tropical Transport: Influence Of The Quasi-Biennial Oscillation, Eugene C. Cordero, S. Randolph Kawa, Mark R. Schoeberl

Faculty Publications, Meteorology and Climate Science

An analysis of over 4 years of Upper Atmosphere Research Satellite (UARS) measurements of CH₄, HF, O₃, and zonal wind are used to study the influence of the quasi-biennial oscillation (QBO) on constituent transport in the tropics. At the equator, spectral analysis of the Halogen Occultation Experiment (HALOE) and Microwave Limb Sounder (MLS) observations reveals QBO signals in constituent and temperature fields at altitudes between 20 and 45 km. Between these altitudes, the location of the maximum QBO amplitude roughly corresponds with the location of the largest vertical gradient in the constituent field. Thus, at 40 …

What Kind Of Thing Is A Number?: A Talk With Reuben Hersh, Reuben Hersh

Humanistic Mathematics Network Journal

No abstract provided.

Math Lingo Vs. Plain English: Multiple Entendre, Stephen I. Brown

Humanistic Mathematics Network Journal

No abstract provided.

Book Review: The Crest Of The Peacock: Non-European Roots Of Mathematics,By George Gheverghese Joseph, Bernadette Anne Berken

Humanistic Mathematics Network Journal

No abstract provided.

Algebra Anyone?, Leslie Jones, Ted Panitz, Walter Burlage

Humanistic Mathematics Network Journal

No abstract provided.

Abe Shenitzer At 75, Hardy Grant

Humanistic Mathematics Network Journal

No abstract provided.