Physical Sciences and Mathematics Commons^™

Interface Relaxation Methods For Elliptic Differential Equations, John R. Rice, P. Tsompanopoulou, E. Vavalis

Department of Computer Science Technical Reports

No abstract provided.

The Grand Tour Of The Ruby-East Humboldt Metamorphic Core Complex, Northeastern Nevada: Part 1-Introduction & Road Log, Arthur W. Snoke, Keith A. Howard, Allen J. Mcgrew, Bradford R. Burton, Calvin G. Barnes, Mark T. Peters, James E. Wright

Geology Faculty Publications

The purpose of this geological excursion is to provide an overview of the multiphase developmental history of the Ruby Mountains and East Humboldt Range, northeastern Nevada. Although these mountain ranges are commonly cited as a classic example of a Cordilleran metamorphic core complex developed through large-magnitude, mid-Tertiary crustal extension, a preceding polyphase Mesozoic contractional history is also well preserved in the ranges. An early phase of this history involved Late Jurassic two-mica granitic magmatism, high-temperature but relatively low-pressure metamorphism, and polyphase deformation in the central Ruby Mountains. In the northern Ruby Mountains and East Humboldt Range, a Late Cretaceous history …

The Contested Domain Of Pastoralism: Landscape, Work And Outsiders In Central Australia , N. J. Gill

Faculty of Science - Papers (Archive)

Extensive cattle grazing has long been the dominant land use in Central Australian rangelands. Today, however, the pastoral landscape is increasingly fractured and contested by indigenous and environmentalist claims on land. Pastoralists in Central Australia are responding to environmentalist claims by reasserting territory. Territory is being constructed with reference to to particular forms of social nature and social space. Identities of insider and outsider have developed. These identities commonly correspond to pastoralists and others, such as conservationists and government, but the place specific nature of pastoralists' environmental knowledge has the potential to render pastoralists as outsiders as well. Moreover, as …

Subcritical, Transcritical And Supercritical Flows Over A Step, Y. Zhang, Song-Ping Zhu

Faculty of Informatics - Papers (Archive)

Free-surface flow over a bottom topography with an asymptotic depth change (a `step') is considered for di erent ranges of Froude numbers varying from subcritical, transcritical, to supercritical. For the subcritical case, a linear model indicates that a train of transient waves propagates upstream and eventually alters the conditions there. This leading-order upstream influence is shown to have profound e ects on higher-order perturbation models as well as on the Froude number which has been conventionally de ned in terms of the steady-state upstream depth. For the transcritical case, a forced Korteweg{de Vries (fKdV) equation is derived, and the numerical …

Minimal Critical Set Of A Room Square Of Order 7, Ghulam R. Chaudhry, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

A Room square R of order r is an r x r array each of whose cells may either be empty or contain an unordered pair of objects 0,1,2,...,r, subject to the following conditions:

(i) each of the objects 0,1,2.....r occurs precisely once in each row of R and precisely once in each column of R, and

(ii) every possible unordered pair of objects occurs precisely once in the whole array.

"Albert Leon Whiteman (1915-1995)", S. Golomb, T. Harris, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

The Mathematical Family Tree of Hans Rademacher (with A. Whiteman branch)

Secure Access To Electronic Strongboxes In Electronic Commerce, Thomas Hardjono, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Two protocols for access to electronic strongbox are described in the context of electronic commerce. The notion of electronic strongboxes is discussed, and the participants of the strongbox system are presented. The two protocols concern two participants of the strongbox systemn namely the Customer who wishes to access a strongbox maintained by a Strongbox Provider. The security aspects of the protocols are then analysed, focusing on possible methods of cheating by the two involved participants.

Factors From Trees, Jacqueline Ramagge, A G. Robertson

Faculty of Informatics - Papers (Archive)

We construct factors of type III,/n for n E N, n > 2, from group actions on homogeneous trees and their boundaries. Our result is a discrete analogue of a result of R.J Spatzier, where the hyperfinite factor of type III1 is constructed from a group action on the boundary of the universal cover of a manifold.

Fernandez Bay, San Salvador, Bahamas: A Natural Laboratory For Assessment Of The Preservation Of Coral Reef Community Structure, Benjamin J. Greenstein, Lora A. Harris, H. Allen Curran

Geosciences: Faculty Publications

Reprinted from: James L. Carew (ed.), Proceedings of the 8th Symposium on the Geology of the Bahamas: San Salvador, Bahamian Field Station

Effects Of Red Imported Fire Ants On Recruitment Of White-Tailed Deer Fawns, Craig R. Allen, Stephen Demarais, R. Scott Lutz

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

We investigated the effect of red imported fire ants (RIFA; Solenopsis invicta) on an index of whitetailed deer (Odocoileus virginianus) fawn recruitment (doe:fawn ratio) on 10 200-ha plots in the Texas Coastal Prairie during 1991-93. Five of the plots received treatments of the fire ant bait AMDRO© (Am. Cyanamid Co., Wayne, N.].) during April and October 1991 and May 1992 to reduce RIFA populations. The remaining 5 plots served as untreated comparison areas. Populations of RIFA were reduced (P < 0.10) on treated study areas during deer fawning periods in 1991-92. Fawn recruitment was higher on treated areas during 1991 (P = 0.037) and 1992 (P = 0.069), with recruitment about twice as high on treated areas. In 1993, after 1 year of RIFA reinfestation, fawn recruitment did not differ between treated and untreated plots (P = 0.443). We conclude that high density RIFA infestations reduced white-tailed deer fawn recruitment.

Environmental Characteristics Of Black Crappie (Pomoxis Nigromaculatus) Nesting Sites In Two South Dakota Waters, K. L. Pope, D. W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

A biotelemetry study was undertaken during spring 1995 to identify black crappie (Pomoxis nigromaculatus) nesting sites in two South Dakota water bodies. Individually coded ultrasonic transmitters were implanted into the body cavity of 15 adult male black crappie in each water body prior to spawning. Available habitat characteristics were recorded at 75 randomly selected sites within each water body, and habitat characteristics at nesting sites were recorded for each male black crappie believed to be nesting. Of the habitat characteristics analyzed, only substrate firmness did not differ (P=0.79) between water bodies. In Richmond Lake, black crappie selected nesting …

Effect Of Red Imported Fire Ant Envenomization On Neonatal American Alligators, Craig R. Allen, Kenneth G. Rice, Daniel P. Wojcik, H. Franklin Percival

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Alligator populations in the southeastern United States have substantially recovered since the late 1960s when they were placed on the federal Endangered Species List (Joanen and McNease, 1987). In Florida, both early age class and adult animals currently are harvested for commercial and recreational purposes (Hines and Abercrombie, 1987). In addition, the alligator is ecologically important as a keystone species and as an indicator of wetland health (Mazzotti and Brandt, 1994). Recently, the nonnative ant Solenopsis invicta (the red imported fire ant) has surfaced as a potential threat to alligator populations. Solenopsis invicta is a relatively new (approx. 65 yr) …

Oxytetracycline Marking Efficacy For Yellow Perch Fingerlings And Temporal Assays Of Tissue Residues, Eric G. Unkenholz, Michael L. Brown, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Differentiating between hatchery and naturally reproduced fishes is difficult because of the lack of appropriate marking techniques. Chemical immersion techniques can be a practical method for mass marking juvenile fishes. The objectives of this study were to determine the concentration of oxytetracycline (OTC) hydrochloride needed to effectively mark age-0 yellow perch Perca flavescens to observe the retention lime of the mark, and to measure the persistence of OTC in body tissues. Fish were immersed in 309, 534, and 748 mg OTC/L for 12 h. Initial fish collections were made weekly, and monthly collections began 1 month postmarking for tissue and …

Convolution And Fourier-Feynman Transforms, Chull Park, David Skough

Department of Mathematics: Faculty Publications

In this paper, for a class of funtionals on Wiener space of the form F(x) = exp{∫^T₀ f(t, x(t)) dt}, we show that the Fourier-Feynman transform of the convolution product is a product of Fourier-Feynman transforms. This allows us to compute the transform of the convolution product without computing the convolution product.

Yellagonga Wetlands: A Study Of The Water Chemistry And Aquatic Fauna, Adrianne Kinnear, Patrick Garnett, Hugo Bekle, K. Upton

Research outputs pre 2011

Wetlands worldwide are continually threatened by urbanisation and Western Australia is no exception. Since European settlement in 1829, it has been estimated that at least 75% of the wetlands of the Swan Coastal Plain have disappeared (Halse, 1988). The remaining 25% continue to be threatened by eutrophication and pollution, changes in hydrology and water level patterns, clearing of riparian vegetation, aesthetic disruption and weed invasion (CALM, 1980; Davis and Rolls, 1987; Wrigley et al., 1991; Balla and Davis, 1995). These degradation components are interrelated and largely the consequence of the extensive removal of surrounding vegetation...

Surface Textural Analysis Of Quartz Sand Grains From Odp Site 918 Off The Southeast Coast Of Greenland Suggests Glaciation Of Southern Greenland At 11 Ma, P. E. Helland, Mary Anne Holmes

Department of Earth and Atmospheric Sciences: Faculty Publications

Shipboard analysis of the 1,183-m sedimentary section recovered at Site 918 in the Irminger Basin during Ocean Drilling Program Leg 152 revealed material of glacial origin (diamictons, ice-rafted debris (IRD) and dropstones) as deep as 543 m below sea floor (bsf). The sediment containing the deepest dropstone was biostratigraphically dated shipboard as approximately 7 Ma, pushing back the date for the onset of glaciation on southern Greenland by 5 Ma. Thin layers of fine sand were found as much as 60 m deeper in the core, raising the possibility of an even earlier date for glaciation. To determine the sedimentary …

Carbon Monoxide Hydrogenation Over Ru-Mn-K/Al_2o_3 Catalysts, S. Tajammul Hussain, M. Ashraf Atta

Turkish Journal of Chemistry

The catalytic behavior of a series Ru/Al_2O_3 catalysts promoted with various levels of Mn and K prepared by coimpregnation were investigated in the CO-hydrogenation reaction. Catalytic studies showed that the addition of Mn enhances the production of Fischer Tropsch products and K promotion in particular enhances the production of unsaturated hydrocarbons while inhibiting the methanation reaction. The influence of K and Mn on the Fischer Tropsch product selectivity in CO-hydrogenation studies is discussed in terms of ensemble and electronic effects, and the production of a new surface site Ru:Mn:K.

Noise-Tolerant Parallel Learning Of Geometric Concepts, Nader H. Bshouty, Sally A. Goldman, H. David Mathias

All Computer Science and Engineering Research

We present several efficient parallel algorithms for PAC-learning geometric concepts in a constant-dimensional space. The algorithms are robust even against malicious classification noise of any rate less than 1/2. We first give an efficient noise-tolerant parallel algorithm to PAC-learn the class of geometric concepts defined by a polynomial number of (d-1)-dimensional hyperplanes against an arbitrary distribution where each hyperplane has a slope from a set of known slopes. We then describe how boosting techniques can be used so that our algorithms' dependence on {GREEK LETTER} and {DELTA} does not depend on d. Next we give an efficient noise-tolerant parallel algorithm …

Noise-Tolerant Distribution-Free Learning Of General Geometric Concepts, Nader H. Bshouty, Sally A. Goldman, H. David Mathias, Subhash Suri, Hisao Tamaki

All Computer Science and Engineering Research

We present an efficient algorithm for PAC-learning a very general class of geometric concepts over Rd for fixed d. More specifically, let T be any set of s halfspaces. Let x = (x1,...,xd) be an arbitrary point in Rd. With each t Є T we associate a boolean indicator function It(x) which is 1 if and only if x is in the halfspace t. The concept class Cds that we study consists of all concepts formed by any boolean function over It1, ...Its for ti Є T. This class is much more general than any geometric concept class known to …

An Error Control Scheme For Large-Scale Multicast Applications, Christos Papadopoulos, Guru Parulkar, George Varghese

All Computer Science and Engineering Research

Retransmission based error control for large scale multicast applications is difficult because of two main problems: request implosion and lack of local recovery. Existing schemes (SRM, RMTP, TMTP, LBRRM) have good solutions to request implosion, but only approximate solutions (e.g., based on scoped multicast) for the local recovery problem. Our scheme achieves finer grain fault recovery by exploiting new forwarding services that allow us to create a dynamic hierarchy of receivers. We use a new paradigm, where routers provide a more refined form of multicasting (that may be useful to other applications), that enables local recovery. The new services, however, …

Reducing Web Latencies Using Precomputed Hints, Girish P. Chandranmenon, George Varghese

All Computer Science and Engineering Research

Current network technology is bandwidth-rich but latency-poor; thus round-trip delays will dominate access latency for web traffic. We describe four new techniques that reduce the round-trips needed for web accesses. The techniques are based on the paradigm of preprocessing a web page to collect information about links and inline data in the page. Stored Address Binding almost always eliminates the DNS lookup (which can cost seconds) at the start of a transaction. In Informed Server Proxying, a server tells its client that it has cached pages referenced in a page the client just retrieved; this allows the client to retrieve …

An Architecture For Monitoring Visualization And Control Of Gigabit Networks, Guru Parulkar, Douglas Schmidt, Eileen Kraemer, Jonathan Turner, Anshul Kantawala

All Computer Science and Engineering Research

We propose a network monitoring, visualization and control system (NMVC) that ensures adequate quality of service to network users while maintaining high network resource utilization. The main components of our system are a network probe, an endsystem probe, software network management agents that provide extensible multi-attribute event filtering for highly scalable data/event collection, network operation centers (NOCs) which can remotely install and (re)configure these agents, efficient online event ordering algorithms that can help synthesize and display a consistent view of network health, status and performance and a View Choreographer that allows management applications and administrators to specify the mapping of …

Euphoria Reference Manual, T. Paul Mccartney, Kenneth J. Goldman

All Computer Science and Engineering Research

EUPHORIA is a user interface management system that enables end-users to create direct manipulation graphical user interfaces (GUIs) through interactive drawing. Used in conjunction with The Programmers' Playground, a distributed programming environment, end-users can dynamically create and associate GUI components with an underlying application without programming, This document describes EUPHORIA's functionality.

Costs Of Constraint Based Networks On A Sphere, Hongzhou Ma, Jonathan Turner

All Computer Science and Engineering Research

This paper estimates the link costs of constraint based nonblocking ATM networks on a sphere. Analytical results are obtained when switches are uniformly distributed on the surface of a unit sphere and every switch has source and sink capacity of one, and the results are compared with simulations.

An Algorithm For Message Delivery In A Micromobility Environment, Amy L. Murphy, Gruia-Catalin Roman, George Varghese

All Computer Science and Engineering Research

With recent advances in wireless communication and the ubiquity of laptops, mobile computing has become an important research area. An essential problem in mobile computing is the delivery of a message from a source to either a single mobile node, unicast, or to a group of mobile nodes, multicast. Standard solutions proposed for macromobility (Mobile IP) and micromobility (cellular phones) for the unicast problem rely on tracking the mobile node. Tracking solutions scale badly when mobile nodes move frequently, and do not generalize well to multicast delivery. Our paper proposes a new message delivery algorithm for micromobility based on a …

Symmetrical Routes And Reverse Path Congestion Control, Rajib Ghosh, George Varghese

All Computer Science and Engineering Research

We describe new mechanisms to deal with asymmetries that arise in routing protocols. We show how to avoid route asymmetries (due to non-unique shortest paths) by adding random integer link costs. We show in detail how RIP can be modified to avoid route asymmetry with high probability, without affecting either its efficiency or performance metrics such as convergence time. Symmetrical intra-domain routing also makes possible a new form of congestion control that we call Reverse Path Congestion Control (RPCC). We show, using simulations, that RPCC can augment existing TCP congestion control mechanisms to improve start up behavior and to avoid …

Enhancements To 4.4 Bsd Unix For Efficient Networked Multimedia In Project Mars, Milind M. Buddhikot, Xin Jane Chen, Dakang Wu, Guru M. Parulkar

All Computer Science and Engineering Research

Cluster based architectures that employ high performance inexpensive Personal Computers (PCs) interconnected by high speed commodity interconnect have been recognized as a cost-effective way of building high performance scalable Multimedia-On-Demand (MOD) storage servers [4, 5, 7, 9]. Typically, the PCs in these architectures run operating systems such as UNIX that have traditionally been optimized for interactive computing. They do not provide fast disk-to-network data paths and guaranteed CPU and storage access. This paper reports enhancements to the 4.4 BSD UNIX system carried out to rectify these limitations in the context of our Project Massively-parallel And Real-time Storage (MARS) [7]. We …

End-User Visualization And Manipulation Of Distributed Aggregate Data, T. Paul Mccartney, Kenneth J. Goldman

All Computer Science and Engineering Research

Aggregate visualization and manipulation enables the viewing and interaction of dynamically changing data sets in a graphically meaningful way. However, off-the-shelf applications typically provide only limited ways to view static aggregates and generally to not support manipulation of aggregate data through the resulting visualization. To be fully dynamic, an aggregate visualization should be customizable to suit the individual's needs and should allow end-users to modify the data through direct manipulation. This paper describes a software system that empowers end-users to create interactive aggregate visualizations through a visual language interface. Included are mechanisms for specifying how aggregate data is processed from …

Replication Of The First Controlled Experiment On The Usefulness Of Design Patterns: Detailed Description And Evaluation, Lutz Prechelt, Barbara Unger, Douglas Schmidt

All Computer Science and Engineering Research

Advocates of software design patterns claim that using design patterns improves communication between software developers. The controled experiment that we describe in this report tests the hypothesis that software maintainers of well-structured, well-documented software containing design patterns can make changes (1) faster and (2) with less errors if the use of patterns is explicitly documented in the software. The experiment was performed with 22 participants of a university course on C++ and design patterns; it is similar to a previous experiment performed in Karlsruhe. For one of the two experiment tasks the experiment finds that both hypotheses appear to be …

Table Of Contents Volume Eight, Number One, Winter 1997, Risk Editorial Board

RISK: Health, Safety & Environment (1990-2002)

Table of contents for the journal RISK: Health, Safety & Environment (ISSN: 1073-8673)