Physical Sciences and Mathematics Commons^™

Experiences Using Case Studies To Teach Risk, A. Fuller, Khin Than Win, L. Dei

Faculty of Informatics - Papers (Archive)

Most software development projects today are facing increased risks. Despite this risk management planning is virtually nonexistent, as managers have not been trained in risk management. Few current software engineering curricula provide comprehensive coverage of risk, nor any practical experience in risk assessment. In this paper we discuss our experience using case studies to teach risk as part of a final year course in software process management with a view to determining the effectiveness of the particular case studies. This experience will be used as a foundation for implementing the full semester course in 2003.

Evaluating Probabilistic Queries Over Imprecise Data, Reynold Cheng, Dmitri V. Kalashnikov, Sunil Prabhakar

Department of Computer Science Technical Reports

No abstract provided.

Magnetic Relaxation Phenomena In The Superspin-Glass System [Co80Fe20/Al2O3]10, Sarbeswar Sahoo, O. Petracic, Christian Binek, Wolfgang Kleemann, J. B. Sousa, Susana Cardoso De Freitas, P. P. Freitas

Christian Binek Publications

Relaxation and temperature cycles of thermoremanent magnetization, M^TRM, in the superspin-glass phase of [Co₈₀Fe₂₀ (0.9 nm)/Al₂O₃ (3 nm)] ₁₀ have been investigated. The relaxation of M^TRM exhibits ageing phenomena. In negative temperature cycles for temperature steps larger than 1 K the magnetic state is retrieved (memory effect) on returning to the measurement temperature. This property is independent of the application of a field step during intermediate cooling. In positive temperature cycles the relaxation is suppressed after temporary heating. The observations are discussed in the light of both the droplet and the …

Microcathodoluminescence And Electron Beam Induced Current Observation Of Dislocations In Freestanding Thick N-Gan Sample Grown By Hydride Vapor Phase Epitaxy, A. Y. Polyakov, A. V. Govorkov, N. B. Smirnov, Z-Q. Fang, David C. Look, Seong-Ju S. Park, J. H. Han

Physics Faculty Publications

Microcathodolumunescence (MCL) spectra measurements, MCL and electron beam induced current (EBIC) imaging of the freestanding n-GaN samples grown by hydride vapor phase epitaxy were made. Dark-spot defects in plan-view EBIC and MCL images and dark line defects in MCL images taken on the cleaved surface of the samples could be associated with dislocations. MCL spectra measurements in the vicinity of dislocations and in the matrix do not reveal specific luminescence bands that could be attributed to dislocations but rather suggest that dislocation regions have higher density of deep nonradiative traps.

Deep Electron And Hole Traps In Freestanding N-Gan Grown By Hydride Vapor Phase Epitaxy, A. Y. Polyakov, N. B. Smirnov, A. V. Govorkov, Z-Q. Fang, David C. Look, Seong-Ju S. Park, J. H. Han

Physics Faculty Publications

Deep level electron and hole traps were studied by means of deep level transient spectroscopy with electrical and optical injection on a freestanding thick n-GaN sample with low dislocation density. It is shown that at both the upper and the lower surface of the sample there exists a thin, ∼0.5 μm layer of damaged material with lowered concentration of electrons and enhanced density of deep centers. Deep in the bulk of the film the densities of the majority of the electron and hole traps are shown to be very low, but measurably higher on the lower face (N face), …

On The Estimation Of Binomial Success Probability With Zero Occurrence In Sample, Mehdi Razzaghi

Journal of Modern Applied Statistical Methods

The problem of estimating the probability of a rare event when the sample shows no incidence of the event is considered. Several methodologies based on various statistical techniques are described and their relative performances are investigated. A decision theoretic approach for estimation of response probability when the sample contains zero responses is examined in depth. The properties of each method are discussed and an example from teratology is used to provide illustration and to demonstrate the results.

Null Distribution Of The Likelihood Ratio Statistic For Feed-Forward Neural Networks, Douglas Landsittel, Harshinder Singh, Vincent C. Arena, Stewart J. Anderson

Journal of Modern Applied Statistical Methods

Despite recent publications exploring model complexity with modern regression methods, their dimensionality is rarely quantified in practice and the distributions of related test statistics are not well characterized. Through a simulation study, we describe the null distribution of the likelihood ratio statistic for several different feed-forward neural network models.

A Simulation Study Of The Impact Of Forecast Recovery For Control Charts Applied To Arma Processes, John N. Dyer, B. Michael Adams, Michael D. Conerly

Journal of Modern Applied Statistical Methods

Forecast-based schemes are often used to monitor autocorrelated processes, but the resulting forecast recovery has a significant effect on the performance of control charts. This article describes forecast recovery for autocorrelated processes, and the resulting simulation study is used to explain the performance of control charts applied to forecast errors.

Accounting For Non-Independent Observations In 2×2 Tables, With Application To Correcting For Family Clustering In Exposure-Risk Relationship Studies, Leslie A. Kalsih, Katherine A. Riester, Stuart J. Pocock

Journal of Modern Applied Statistical Methods

Participants in epidemiologic studies may not represent statistically independent observations. We consider modifications to conventional analyses of 2×2 tables, including Fisher’s exact test and confidence intervals, to account for correlated observations in this setting. An example is provided, assessing the robustness of conclusions from a published analysis.

Combining Quantum Mechanical Calculations And A Χ^2 Fit In A Potential Energy Function For The Co_2 + O^+ Reaction, Ellen F. Sawilowsky

Journal of Modern Applied Statistical Methods

In order to compute a highly accurate statistical rate constant for the CO2 + O⁺ reaction, it is necessary to first calculate the potential energy of the system at many different geometric configurations. Quantum mechanical calculations are very time-consuming, making it difficult to obtain a sufficient number to allow for accurate interpolation. The number of quantum mechanical calculations required can be significantly reduced by using known relations in classical physics to calculate energy for configurations where the oxygen is relatively far from the CO2. A chi-squared fit to quantum mechanical points is obtained for these configurations, and the resulting …

Type I Error Rates For Rank-Based Tests Of Homogeneity Of Slopes, Alan J. Klockars, Tim P. Moses

Journal of Modern Applied Statistical Methods

The purpose of this study was to explicate two issues concerning the standard and rank based test of homogeneity of slopes. Two alternative ranking methods intended to address nonnormality and additive treatment effect patterns were developed and compared in terms of their ability to control Type I error. The results replicated previous findings of inflated Type I error rates with leptokurtic curves and with rank based tests with some patterns of additive treatment effects. The new nonparametric procedures generally control Type I error although they were slightly inflated with skewed distributions.

Exploration Of Distributions Of Ratio Of Partial Sum Of Sample Eigenvalues When All Population Eigenvalues Are The Same, Moonseong Heo

Journal of Modern Applied Statistical Methods

This paper explores empirically the first two moments of ratio of the partial sum of the first two sample eigenvalues to the sum of all eigenvalues when the population eigenvalues of a covariance matrix are all the same. Estimation of the first two moments can be practically crucial in assessing non-randomness of observed patterns on planar graphical displays based on lower rank approximations of data matrices. For derivation of the moments, exact and large sample asymptotic distributions of the sample ratios are reviewed but neither can be applicable to derivation of the moments. Therefore, I rely on simulations, where data …

On Distribution Function Estimation Using Double Ranked Set Samples With Application, Walid A. Abu-Dayyeh, Hani M. Samawi, Lara A. Bani-Hani

Journal of Modern Applied Statistical Methods

As a variation of ranked set sampling (RSS); double ranked set sampling (DRSS) was introduced by Al-Saleh and Al-Kadiri (2000), and it has been used only for estimating the mean of the population. In this paper DRSS will be used for estimating the distribution function (cdf). The efficiency of the proposed estimators will be obtained when ranking is perfect. Some inference on the distribution function will be drawn based on Kolomgrov-Smirnov statistic. It will be shown that using DRSS will increase the efficiency in this case.

A Program For Generating All Permutations Of {1, 2, ..., N}, Robert Disario

Journal of Modern Applied Statistical Methods

A Visual Basic program that generates all permutations of {1, 2, ..., n} is presented. The procedure for running the program as an Excel macro is described. An application is presented which involves selecting permutations which meet a specific constraint.

A Perspective On Two Decades Of Policies And Regulations Influencing The Protection And Restoration Of Submerged Aquatic Vegetation In Chesapeake Bay, Usa, R J. Orth, Ra Batiuk, Pw Bergstrom, Ken Moore

VIMS Articles

Seagrasses along with many other species of freshwater rooted submerged macrophytes in Chesapeake Bay (collectively called SAV) underwent serious declines in population abundances in the 1970s and have not as yet rebounded to previous levels. Cooperative efforts by scientists, politicians, federal and state resource managers, and the general public have developed policies and plans to protect, preserve and enhance SAV populations of Chesapeake Bay. These include the Chesapeake Bay Agreements (1983, 1987, 1992, 1993, 2000), an SAV Management Policy and Implementation Plan for Chesapeake Bay and Tidal Tributaries (1989 and 1990), Chesapeake Bay Blue Crab Fishery Management Plan (1997), as …

Effect Of An Electric Field On The Surface Tension Of A Dipolar-Quadrupolar Fluid And Its Implication For Sign Preference In Droplet Nucleation, V.B. Warshavsky, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The effect of a uniform electric field on interfacial properties of dipolar-quadrupolar fluids is investigated by using the density-functional theory. As in the case of purely dipolar fluids the (thermodynamic) surface tension is always altered by the external field, regardless of the direction of the field. However, unlike the purely dipolar fluids, for two given external fields with the same strength but exactly opposite direction the magnitude of variation in the surface tension is different. This apparent symmetry breaking by reversing the field direction suggests a new molecular mechanism to explain the phenomenon of sign preference in droplet formation on …

Two Quick Combinatorial Proofs, Arthur T. Benjamin, Michael E. Orrison

All HMC Faculty Publications and Research

Presentation of two simple combinatorial proofs.

Chronic Disease Data And Analysis: Current State Of The Field, Ralph D'Agostino Sr., Lisa M. Sullivan

Journal of Modern Applied Statistical Methods

Chronic disease usually spans years of a person’s lifetime and includes a disease free period, a preclinical, or latent period, where there are few overt signs of disease, a clinical period where the disease manifests and is eventually diagnosed, and a follow-up period where the disease might progress steadily or remain stable. It is often of interest to investigate the relationship between risk factors measured at a point in time (usually during the disease free or preclinical period), and the development of disease at some future point (e.g., 10 years later). We outline some popular designs for the identification of …

Curie Temperature Of Fept:B2O3 Nanocomposite Films, H. Zeng, Renat F. Sabirianov, O. Mryasov, M.L. Yan, K. Cho, David J. Sellmyer

David Sellmyer Publications

We report results on experimental and theoretical studies of structural and magnetic properties of FePt: B₂O₃ nanocomposite films. It was found for films prepared by magnetron sputtering with subsequent annealing that lattice parameters a and c of fct FePt change with significantly different rates with increase of the B₂O₃ fraction. As a consequence, fundamental magnetic properties change markedly, with the Curie temperature decreasing by 36% for 25% FePt volume fraction compared with the bulk value. Using an ab initio parametrization of magnetic interactions, we propose statistical model of thermal fluctuations in fct FePt, which …

The Capacity Of Multi-Hop Wireless Networks With Tcp Regulated Traffic, Sorav Bansal, Rajeev Shorey, Shobhit Chugh, Anurag Goel, Kapil Kumar, Archan Misra

Research Collection School Of Computing and Information Systems

We study the dependence of the capacity of multi-hop wireless networks on the transmission range of nodes in the network with TCP regulated traffic. Specifically, we examine the sensitivity of the capacity to the speed of the nodes and the number of TCP connections in an ad hoc network. By incorporating the notion of a minimal acceptable QoS metric (loss) for an individual session, we argue that the QoS-aware capacity is a more accurate model of the TCP-centric capacity of an ad-hoc network. We study the dependence of capacity on the source application (Telnet or FTP) and on the choice …

The Nadca Probe, Issue 225

The Probe: Newsletter of the National Animal Damage Control Association

Beaver Management- Nevada 1942-1943

CALENDAR OF UPCOMING EVENTS

If I think an animal may have been poisoned or exposed to a toxin, is there a source of information-a non-human animal poison control center?

"The Critter Control Handbook: Pro Secrets for Stopping Sneaky Squirrels & Other Crafty Critters in Their Tracks" by Dan "The Critter Man" Hershey.

U.S. Sportsmen's Alliance Launches Assault on an Animal Rights Movement

Rodent Rabies - Bolivia

Counter Terrorism Includes Animal Rights and Eco-Violence

High Frequency-Bandwidth Optical Technique To Measure Thermal Elongation Time Responses Of Near-Field Scanning Optical Microscopy Probes, Andres H. La Rosa, B. Biehler

Physics Faculty Publications and Presentations

A near-field scanning optical microscopy (NSOM) probe elongates when light is coupled into it. The time response of this thermal process is measured here by a new optical technique that exploits the typical flat-apex morphology of the probe as a mirror in a Fabry-Perot type cavity. Pulsed laser light is coupled into the probe to heat up the tip, while another continuous wave laser serves to monitor the elongation from the interference pattern established by the reflections from the flat-apex probe and a semitransparent metal-coated flat sample. A quarter wave plate is introduced into the interferometer optical path in order …

Nonlocal Electrodynamic Modeling Of Fluorescence Characteristics For Molecules In A Spherical Cavity, Pui T. Leung, M. H. Hider

Physics Faculty Publications and Presentations

The emission characteristics for molecules in a spherical metallic microcavity are computed using a nonlocal electrodynamic model, based on a theory previously published by Fuchs and Claro [Phys. Rev. B 35, 3722 (1987)] for the multipole polarizability of a sphere. Both radially and tangentially oriented molecules at arbitrary locations inside the cavity are considered, and the results are compared with those from both the local response theory and those for molecules outside a spherical particle. The issue of reciprocity of the solutions for each of the sphere and cavity cases, respectively, is examined in the light of the nonlocal effects. …

Horizontal-Branch Morphology And The Photometric Evolution Of Old Stellar Populations, Hyun Chul Lee, Young Wook Lee, Brad K. Gibson

Physics and Astronomy Faculty Publications and Presentations

Theoretical integrated broadband colors ranging from far-UV to near-IR have been computed for old stellar systems from our evolutionary population synthesis code. These models take into account, for the first time, the detailed systematic variation of horizontal-branch (HB) morphology with age and metallicity. Our models show that some temperature-sensitive color indices are significantly affected by the presence of blue HB stars. In particular, B-V does not become monotonically redder as metallicity increases at given ages, but becomes bluer by as much as ∼0.15 mag because of the contribution from blue HB stars. Similar trends are also found in the Washington …

Data Summary From The Tampa Bay Interagency Seagrass Monitoring Program Through The Year 2001, Roger Johansson, Walt Avery

Reports

This paper presents a general overview of the Tampa Bay Interagency Seagrass Monitoring Program and results concerning seagrass distribution within Tampa Bay. Further, a summary of trends in areal coverage and major changes in species composition observed during the course of the monitoring program are also included. Data collected during the course of the program pertaining to water quality, sediment composition, and epiphytes are not discussed within this report. All inf

Federal Consistency In New Jersey, Urban Harbors Institute, University Of Massachusetts Boston

Urban Harbors Institute Publications

A discussion paper prepared as part of a focus group on the topic of Federal Consistency in New Jersey.

In 1972, the U. S. Congress passed the Coastal Zone Management Act (CZMA), designed to “preserve, protect, develop, and where possible, to restore and enhance the resources of the nation's coastal zone.” The CZMA encouraged coastal states to develop and implement comprehensive management programs that balance the need for coastal resource protection with the need for economic growth and development within the coastal zone.

In the latter portion of the 1970s New Jersey developed a coastal management plan that was fully …

Fragmentation Processes Following Core Excitation In Acetylene And Ethylene By Partial Ion Yield Spectroscopy, Maria Novella Piancastelli, Wayne C. Stolte, Gunnar Ohrwall, S-W Yu, D. Bull, K. Lantz, Alfred S. Schlachter, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

Partial ion yield spectroscopy provides a very detailed picture of fragmentation processes following core excitation in isolated molecules. We exploit this potential in the analysis of decay processes following C1s→π and C1s→Rydberg excitations in ethylene and acetylene. We show that the relative intensity of spectral features related to the excitation to empty molecular orbitals or to Rydberg states is a function of the time variation of the fragmentation process. Namely, we see an intensity increase in the Rydberg states compared to the molecular orbitals as the fragmentation process becomes more extensive, a result attributable to the diffuse nature of the …

Influence Of Terrain On Scaling Laws For River Networks, D. A. Vasquez, D. H. Smith, Boyd F. Edwards

All Physics Faculty Publications

The upper Cheat River network departs from scaling laws describing a large number of river networks in North America. This departure is traced to its corrugated terrain. The more typical random terrain of the lower Cheat River network obeys the standard scaling laws. We modify the random network model of Scheidegger to include the effects of topography, reproducing the behavior observed in the Cheat River basin.

Statistical Characteristics Ofsprite Halo Events Using Coincident Photometric And Imaging Data, R. Miyasato, Michael J. Taylor, H. Fukunishi, Y. Takahashi, H. Nielsen

All Physics Faculty Publications

Sprite halos are brief, diffuse flashes, which occur at the top of a sprite and precede the development of streamer structures at lower altitudes. We have investigated the characteristics of sprite halos in detail using coincident photometric and imaging data obtained during the Sprites'96 and '99 campaign in Colorado and Wyoming, USA. It is found that the average altitude of the centroid of the halo emission and the mean horizontal diameter of the halo events are ∼80 and ∼86 km, respectively, while the average speed of the descending motion of the sprite halos was ∼4.3 × 10⁷ m/s. It …

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.