Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

1999

Series

Portland State University

Discipline
Keyword
Publication

Articles 1 - 30 of 34

Full-Text Articles in Physical Sciences and Mathematics

A Comparison Of Training Algorithms For Dhp Adaptive Critic Neuro-Control, George G. Lendaris, Thaddeus T. Shannon, Andres Rustan Dec 1999

A Comparison Of Training Algorithms For Dhp Adaptive Critic Neuro-Control, George G. Lendaris, Thaddeus T. Shannon, Andres Rustan

Systems Science Faculty Publications and Presentations

A variety of alternate training strategies for implementing the Dual Heuristic Programming (DHP) method of approximate dynamic programming in the neuro-control context are explored. The DHP method of controller training has been successfully demonstrated by a number of authors on a variety of control problems in recent years, but no unified view of the implementation details of the method has yet emerged. A number of options are here described for sequencing the training of the Controller and Critic networks in DHP implementations. Results are given about their relative efficiency and the quality of the resulting controllers for two benchmark control …

Go to article

Work In Progress: Automating Proportion/Period Scheduling, David Steere, Jonathan Walpole, Calton Pu Dec 1999

Work In Progress: Automating Proportion/Period Scheduling, David Steere, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

The recent effort to define middleware capable of supporting real-time applications creates the opportunity to raise the level of abstraction presented to the programmer. We propose that proportion/period is a better abstraction for specifying resource needs and allocation than priorities. We are currently investigating techniques to address some issues that are restricting use of proportion/period scheduling to research real-time prototypes. In particular, we are investigating techniques to automate the task of selecting proportion and period, and that allow proportion/period to incorporate job importance under overload conditions.

Go to article

A New Numerical Model Of Coupled Inland Ice Sheet, Ice Stream, And Ice Shelf Flow And Its Application To The West Antarctic Ice Sheet, Christina L. Hulbe, D. R. Macayeal Nov 1999

A New Numerical Model Of Coupled Inland Ice Sheet, Ice Stream, And Ice Shelf Flow And Its Application To The West Antarctic Ice Sheet, Christina L. Hulbe, D. R. Macayeal

Geology Faculty Publications and Presentations

We have developed a dynamic/thermodynamic finite element numerical model that couples inland ice sheet, ice stream, and ice shelf dynamics. This new model stands apart from other whole ice sheet models in its explicit treatment of ice stream flow. Additionally, the model accounts for both horizontal and vertical advection and diffusion of temperature in the flowing ice. In present day simulations of the West Antarctic Ice Sheet (WAIS), modeled ice velocity agrees well with observed ice flow. In particular, the model reproduces the pattern of speed variation across ice streams although the continuous downstream speed up of ice flow cannot …

Go to article

Investigation Of Image Feature Extraction By A Genetic Algorithm, Steven P. Brumby, James P. Theiler, Simon J. Perkins, Neal R. Harvey, John J. Szymanski, Jeffrey J. Bloch, Melanie Mitchell Nov 1999

Investigation Of Image Feature Extraction By A Genetic Algorithm, Steven P. Brumby, James P. Theiler, Simon J. Perkins, Neal R. Harvey, John J. Szymanski, Jeffrey J. Bloch, Melanie Mitchell

Computer Science Faculty Publications and Presentations

We describe the implementation and performance of a genetic algorithm which generates image feature extraction algorithms for remote sensing applications. We describe our basis set of primitive image operators and present our chromosomal representation of a complete algorithm. Our initial application has been geospatial feature extraction using publicly available multi-spectral aerial-photography data sets. We present the preliminary results of our analysis of the efficiency of the classic genetic operations of crossover and mutation for our application, and discuss our choice of evolutionary control parameters. We exhibit some of our evolved algorithms, and discuss possible avenues for future progress.

Go to article

Human History As A Natural Science. Review Of: Guns, Germs, And Steel: The Fates Of Human Societies By Jared Diamond, Robert Costanza Oct 1999

Human History As A Natural Science. Review Of: Guns, Germs, And Steel: The Fates Of Human Societies By Jared Diamond, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

Book review of Guns, Germs, and Steel: The Fates of Human Societies. Jared Diamond. W. W. Norton, New York, 1997.

Go to article

Capillary Surfaces In An Exotic Container: Results From Space Experiments, Paul Concus, Robert Finn, Mark M. Weislogel Sep 1999

Capillary Surfaces In An Exotic Container: Results From Space Experiments, Paul Concus, Robert Finn, Mark M. Weislogel

Mechanical and Materials Engineering Faculty Publications and Presentations

Experimental results from the Interface Configuration Experiment (ICE) performed aboard the Space Shuttle and the Mir Space Station are reported. The experiment concerns fluid interfaces in certain ‘exotic’ containers in a low-gravity environment. These containers are rotationally symmetric and have the property that for given contact angle and liquid volume, a continuum of distinct rotationally symmetric equilibrium configurations can appear, all of which have the same mechanical energy. These symmetric equilibrium configurations are unstable, in that deformations that are not rotationally symmetric can be shown mathematically to yield configurations with lower energy. It is found experimentally, in confirmation of mathematical …

Go to article

Addendum: "Bethe Stopping-Power Theory For Heavy-Target Atoms", P.T. Leung Sep 1999

Addendum: "Bethe Stopping-Power Theory For Heavy-Target Atoms", P.T. Leung

Physics Faculty Publications and Presentations

Our previous result on the correction of the Bethe stopping power theory for heavy target elements is amended, with the application of a more consistent version of the semirelativistic Bethe sum rule worked out recently [Phys. Rev. A 57, 4994 (1998)]. This correction is found to be significant for high-Z target atoms and relatively high-energy incident particles.

Go to article

Fine-Grain Period Adaptation In Soft Real-Time Environments, David Steere, Joshua Gruenberg, Dylan Mcnamee, Calton Pu, Jonathan Walpole Sep 1999

Fine-Grain Period Adaptation In Soft Real-Time Environments, David Steere, Joshua Gruenberg, Dylan Mcnamee, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Reservation-based scheduling delivers a proportion of the CPU to jobs over a period of time. In this paper we argue that automatically determining and assigning this period is both possible and useful in general purpose soft real-time environments such as personal computers and information appliances. The goal of period adaptation is to select the period over which a job is guaranteed to receive its portion of the CPU dynamically and automatically. The choice of period represents a trade-off between the amount of jitter observed by the job and the overall efficiency of the system. Secondary effects of period include quantization …

Go to article

Anomalous Low-Temperature And High-Field Magnetoresistance In The Organic Superconductor Β″-(Bedt-Ttf)2sf5ch2cf2so3, F. Zuo, X. Su, P. Zhang, J. S. Brooks, J. Wosnitza, J. A. Schlueter, Jack M. Williams, P. G. Nixon, Rolf Walter Winter, Gary L. Gard Sep 1999

Anomalous Low-Temperature And High-Field Magnetoresistance In The Organic Superconductor Β″-(Bedt-Ttf)2sf5ch2cf2so3, F. Zuo, X. Su, P. Zhang, J. S. Brooks, J. Wosnitza, J. A. Schlueter, Jack M. Williams, P. G. Nixon, Rolf Walter Winter, Gary L. Gard

Chemistry Faculty Publications and Presentations

We report direct observations of anomalous magnetic-field and temperature dependences of the Shubnikov–de Haas oscillations in the organic superconductor β″-(BEDT-TTF)₂SF₅CH₂CF₂SO₃. Unlike other BEDT-TTF based organic superconductors, a nonmetallic temperature dependence of the background magnetoresistance is clearly observed. It is speculated that the nonmetallic behavior may arise from a partial nesting of the open orbits, similar to the field-induced density wave in the quasi-one-dimensional systems or a charge localization. The analysis of the magnetoresistance oscillations are found to deviate from the conventional Lifshitz-Kosevich description at high field and low temperatures. [S0163-1829(99)05433-8]

Go to article

Qos Scalability For Streamed Media Delivery, Charles Krasic, Jonathan Walpole Sep 1999

Qos Scalability For Streamed Media Delivery, Charles Krasic, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Applications with real-rate progress requirements, such as mediastreaming systems, are difficult to deploy in shared heterogenous environments such as the Internet. On the Internet, mediastreaming systems must be capable of trading off resource requirements against the quality of the media streams they deliver, in order to match wide-ranging dynamic variations in bandwidth between servers and clients. Since quality requirements tend to be user- and task-specific, mechanisms for capturing quality of service requirements and mapping them to appropriate resource-level adaptation policies are required. In this paper, we describe a general approach for automatically mapping user-level quality of service specifications onto resource …

Go to article

Simple Model For Linear And Nonlinear Mixing At Unstable Fluid Interfaces In Spherical Geometry, John D. Ramshaw Aug 1999

Simple Model For Linear And Nonlinear Mixing At Unstable Fluid Interfaces In Spherical Geometry, John D. Ramshaw

Physics Faculty Publications and Presentations

A simple model was recently described for predicting linear and nonlinear mixing at an unstable planar fluid interface subjected to an arbitrary time-dependent variable acceleration history [J. D. Ramshaw, Phys. Rev. E 58, 5834 (1998)]. Here we present an analogous model for describing the mixing of two adjacent spherical fluid shells of different density resulting from an arbitrary time-dependent mean interface radius R(t). As in the planar case, the model is based on a heuristic expression for the kinetic energy of the system. This expression is based on that for the kinetic energy of a linearly perturbed interface, but with …

Go to article

Modeling Macrophytes Of The Columbia Slough, Oregon, Chris Berger, Scott A. Wells Aug 1999

Modeling Macrophytes Of The Columbia Slough, Oregon, Chris Berger, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The Columbia Slough is a tidally influenced freshwater system of wetlands, channels, and lakes located within the Portland, Oregon metropolitan area at the confluence of the Willamette and Columbia Rivers. It is a eutrophic water body susceptible to algae blooms and crashes and periods of high pH which violate water quality standards. High nutrient loads from groundwater principally controls algae productivity. Past structural changes to the Columbia Slough have included filling of wetlands and lakes and the construction of levees, dikes, culverts and irrigation channels. These changes have altered the natural flow dynamics creating an environment more conducive to eutrophication. …

Go to article

Optical Properties Of Β″-(Et)2sf5ch2cf2so3: A Layered Molecular Superconductor With Large Discrete Counterions, J. Dong, J. L. Musfeldt, J. A. Schlueter, Jack M. Williams, P. G. Nixon, Rolf Walter Winter, Gary L. Gard Aug 1999

Optical Properties Of Β″-(Et)2sf5ch2cf2so3: A Layered Molecular Superconductor With Large Discrete Counterions, J. Dong, J. L. Musfeldt, J. A. Schlueter, Jack M. Williams, P. G. Nixon, Rolf Walter Winter, Gary L. Gard

Chemistry Faculty Publications and Presentations

We report the polarized infrared and optical reflectance of β″-(ET)₂SF₅CH₂CF₂SO₃ as a function of temperature. This fully organic superconductor displays weakly metallic behavior over the entire temperature range of our investigation. The electronic properties present several unusual features including the lack of a conventional free carrier (Drude) response at low temperature, infrared localization phenomena, and an unexpected temperature dependence of the oscillator strength. Similar behavior is observed in other β and β″ superconductors above Tc, suggesting that this class of compounds is very close to a metal→insulator transition where electronic correlations are important and the Drude response carries very little …

Go to article

One Giant Leap. Review Of: Consilience: The Unity Of Knowledge By Edward O. Wilson, Robert Costanza Jun 1999

One Giant Leap. Review Of: Consilience: The Unity Of Knowledge By Edward O. Wilson, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

Book review of Consilience: The Unity of Knowledge. Edward O. Wilson. Knopf, New York, 1998.

Go to article

Comment On "Relativistic Correction Of The Generalized Oscillator Strength Sum Rules", P.T. Leung, Scott M. Cohen Jun 1999

Comment On "Relativistic Correction Of The Generalized Oscillator Strength Sum Rules", P.T. Leung, Scott M. Cohen

Physics Faculty Publications and Presentations

Romero and Aucar [Phys. Rev. A 57, 2212 (1998)] have found a vanishing result for the relativistic correction to the dipole sum rule ∆S1 for a one-electron system. They have given a result for the dipole sum rule ∆S2 as well. We argue that these results are both incorrect and show explicitly that their approach yields a nonvanishing result for ∆S1. The corrected result is in agreement with that which we have obtained in a recent paper, in which we present explicit expressions for ∆S1, ∆S2, and several other more general sum rules.

Go to article

Near-Field Fluorescence Microscopy Based On Two-Photon Excitation With Metal Tips, Erik J. Sánchez, Lukas Novotny, X. Sunney Xie May 1999

Near-Field Fluorescence Microscopy Based On Two-Photon Excitation With Metal Tips, Erik J. Sánchez, Lukas Novotny, X. Sunney Xie

Physics Faculty Publications and Presentations

We present a new scheme for near-field fluorescence imaging using a metal tip illuminated with femtosecond laser pulses of proper polarization. The strongly enhanced electric field at the metal tip (ap15 nm end diameter) results in a localized excitation source for molecular fluorescence. Excitation of the sample via two-photon absorption provides good image contrast due to the quadratic intensity dependence. The spatial resolution is shown to be better than that of the conventional aperture technique. We used the technique to image fragments of photosynthetic membranes, as well as j-aggregates with spatial resolutions on the order of 20 nm.

Go to article

Measurement Of Free Radicals Oh And Ho₂ In Los Angeles Smog, Linda Acha George, Thomas M. Hard, Robert J. O'Brien May 1999

Measurement Of Free Radicals Oh And Ho₂ In Los Angeles Smog, Linda Acha George, Thomas M. Hard, Robert J. O'Brien

Environmental Science and Management Faculty Publications and Presentations

Atmospheric free radicals hydroxyl and hydroperoxyl (OH and HO₂, collectively HOᵪ ) are the catalysts that cause secondary or photochemical air pollution. Chemical mechanisms for oxidant and acid formation, on which expensive air pollution control strategies are based, must accurately predict these radical concentrations. We have used the fluorescence assay with gas expansion (FAGE) technique to carry out the first simultaneous, in situ measurements of these two radicals in highly polluted air during the Los Angeles Free Radical Experiment. A complete suite of ancillary measurements was also made, including speciated hydrocarbons, carbon monoxide, aldehydes, nitric oxide, nitrogen dioxide, and ozone …

Go to article

Natural Emissions Of Chlorine-Containing Gases: Reactive Chlorine Emissions Inventory, M. A. K. Khalil, R. M. Moore, D. B. Harper, J. M. Lobert, D. J. Erickson, V. Koropalov, W. T. Sturges, W. C. Keene Apr 1999

Natural Emissions Of Chlorine-Containing Gases: Reactive Chlorine Emissions Inventory, M. A. K. Khalil, R. M. Moore, D. B. Harper, J. M. Lobert, D. J. Erickson, V. Koropalov, W. T. Sturges, W. C. Keene

Physics Faculty Publications and Presentations

Although there are many chlorine-containing trace gases in the atmosphere, only those with atmospheric lifetimes of 2 years or fewer appear to have significant natural sources. The most abundant of these gases are methyl chloride, chloroform, dichloromethane, perchloroethylene, and trichloroethylene. Methyl chloride represents about 540 parts per trillion by volume (pptv) Cl, while the others together amount to about 120 pptv Cl. For methyl chloride and chloroform, both oceanic and land-based natural emissions have been identified. For the other gases, there is evidence of oceanic emissions, but the roles of the soils and land are not known and have not …

Go to article

Globalization And The Sustainability Of Human Health: An Ecological Perspective, Robert Costanza, A. J. Mcmichael, Bert Bolin, Gretchen C. Daily, Carl Folke, Kerstin Lindahl-Kiessling, Elisabet Lindgren, Bo Niklasson Mar 1999

Globalization And The Sustainability Of Human Health: An Ecological Perspective, Robert Costanza, A. J. Mcmichael, Bert Bolin, Gretchen C. Daily, Carl Folke, Kerstin Lindahl-Kiessling, Elisabet Lindgren, Bo Niklasson

Institute for Sustainable Solutions Publications and Presentations

The last half-century has seen momentous and accelerating changes in humankind's economic activities, political relations, and social and demographic profile. A prominent feature of this change is the increasing scale of human impact on Earth's natural biophysical systems: the climate system, stratospheric ozone, biodiversity, terrestrial and marine food-producing ecosystems, and the great cycles of water, nitrogen, and sulfur (Meyer 1996, Vitousek et al. 1997). These systems sustain the conditions on which life depends, and their weakening may therefore have profound long-term implications for human population health (McMichael 1993, Last 1997).

Go to article

Prestructuring Neural Networks Via Extended Dependency Analysis With Application To Pattern Classification, George G. Lendaris, Thaddeus T. Shannon, Martin Zwick Mar 1999

Prestructuring Neural Networks Via Extended Dependency Analysis With Application To Pattern Classification, George G. Lendaris, Thaddeus T. Shannon, Martin Zwick

Systems Science Faculty Publications and Presentations

We consider the problem of matching domain-specific statistical structure to neural-network (NN) architecture. In past work we have considered this problem in the function approximation context; here we consider the pattern classification context. General Systems Methodology tools for finding problem-domain structure suffer exponential scaling of computation with respect to the number of variables considered. Therefore we introduce the use of Extended Dependency Analysis (EDA), which scales only polynomially in the number of variables, for the desired analysis. Based on EDA, we demonstrate a number of NN pre-structuring techniques applicable for building neural classifiers. An example is provided in which EDA …

Go to article

Four Visions Of The Century Ahead: Will It Be Star Trek, Ecotopia, Big Government Or Mad Max?, Robert Costanza Feb 1999

Four Visions Of The Century Ahead: Will It Be Star Trek, Ecotopia, Big Government Or Mad Max?, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

Lays out different visions as to what the 21st century will be like. Where these visions are based; Default technological optimist vision; Technological skeptic's nightmare; War between public interest and private enterprise; Low-consumption sustainable vision; How society should decide among the visions; Challenges.

Go to article

Internal Temperature Of Douglas-Fir Buds Is Altered At Elevated Temperature, Martha E. Apple, Melissa S. Lucash, David M. Olszyk, David T. Tingey, Donald L. Phillips Feb 1999

Internal Temperature Of Douglas-Fir Buds Is Altered At Elevated Temperature, Martha E. Apple, Melissa S. Lucash, David M. Olszyk, David T. Tingey, Donald L. Phillips

Environmental Science and Management Faculty Publications and Presentations

Pseudotsuga menziesii (Douglas-fir) saplings were grown in sun-lit controlled environment chambers at ambient or elevated (4°C above ambient) temperature. We measured internal temperatures of vegetative buds with thermocouple probes and compared temperatures of normal buds and abnormal buds with loosened, rosetted outer scales in elevated temperature chambers. The abnormal buds had higher and earlier peak daily temperatures than normal buds. Elevated temperature may influence the internal temperature of buds and contribute to the development of abnormal, rosetted buds with loosened outer scales. Abnormal bud development may alter branching patterns and allometry of Douglas-fir trees subjected to climatic change.

Go to article

Anisotropic Magnetoresistance In The Organic Superconductor Β″–(Bedt-Ttf)2sf5ch2cf2so3, X. Su, F. Zuo, J. A. Schlueter, Jack M. Williams, P. G. Nixon, Rolf Walter Winter, Gary L. Gard Feb 1999

Anisotropic Magnetoresistance In The Organic Superconductor Β″–(Bedt-Ttf)2sf5ch2cf2so3, X. Su, F. Zuo, J. A. Schlueter, Jack M. Williams, P. G. Nixon, Rolf Walter Winter, Gary L. Gard

Chemistry Faculty Publications and Presentations

In this paper, we report transport measurements of interlayer magnetoresistance with field parallel and perpendicular to the current direction in an all organic superconductor β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃. For H∥I, the isothermal magnetoresistance R(H) at low temperatures (T

Go to article

Guide For Developing Integrated Aquatic Vegetation Management Plans In Oregon, Maribeth Gibbons, Mark Rosenkranz, Harry L. Gibbons, Mark Sytsma Jan 1999

Guide For Developing Integrated Aquatic Vegetation Management Plans In Oregon, Maribeth Gibbons, Mark Rosenkranz, Harry L. Gibbons, Mark Sytsma

Center for Lakes and Reservoirs Publications and Presentations

This manual focuses on controlling nuisance aquatic plants, occurring in Oregon lakes. To use this manual, it is necessary to distinguish between an aquatic plant problem, and a water quality enrichment problem that typically results in excessive algae production (See Box this page). The most serious type of aquatic plant problem is caused by invasion of a waterbody by a non-native species. Non-native weed invaders may flourish in suitable conditions and degrade habitat and other beneficial uses. The biology and ecology of weeds allows them to fluorish under a wide range of conditions. Nutrient enrichment is not a prerequisite for …

Go to article

Aquatic Vegetation In Irrigation Canals, Mark Sytsma, Michael Parker Jan 1999

Aquatic Vegetation In Irrigation Canals, Mark Sytsma, Michael Parker

Center for Lakes and Reservoirs Publications and Presentations

Preparation of this guidance manual for integrated aquatic vegetation management in irrigation canals was stimulated, in large part, by the accidental release of acrolein-treated irrigation water into Bear Creek in southern Oregon. The resulting fish kill brought into focus the need to examine the methods available for managing aquatic vegetation in flowing water. Furthermore, it demonstrated the need for technical assistance on aquatic vegetation management in Oregon. Vegetation management in flowing water is a difficult undertaking. The interconnectedness of natural and manmade water conveyance systems, the tenuous status of many aquatic species, and the necessity of water delivery for profitable …

Go to article

Approaching Critical Thinking Through Science, Linda A. George, Jack C. Straton Jan 1999

Approaching Critical Thinking Through Science, Linda A. George, Jack C. Straton

Physics Faculty Publications and Presentations

One unanticipated development of University Studies is the degree to which it rapidly became seen not just as general education, but as the replacement for all generally re quired courses. Because the natural sciences had com prised one of the distribution areas of the old program, expectations that the new program would teach science quickly flowered, although exactly what faculty mean by that term has yet to be established. In fact, discussions of what we intend by science education have brought in creased attention to these expectations as we continually revisit the goals of University Studies. The matter is far …

Go to article

Chlorine-Containing Gases In Antarctica, M. A. K. Khalil, R. A. Rasmussen Jan 1999

Chlorine-Containing Gases In Antarctica, M. A. K. Khalil, R. A. Rasmussen

Physics Faculty Publications and Presentations

In recent years, there has been considerable interest in chlorine-containing trace gases in the atmosphere, particularly in Antarctica because of the relationship between chlorofluorocarbons and the antarctic ozone hole. All chlorinecontaining trace gases, whether produced by human activities or by natural processes, have a potential for destroying ozone in the stratosphere. This is a complex environmental problem, but it is clear that manmade chlorine-containing gases are the driving force behind the antarctic ozone hole and, by extension, reductions of stratospheric ozone over other parts of the world [World Meteorological Organization (WMO) 1989, 1991, 1995]. We have taken measurements of the …

Go to article

Geometrical Models For Grain Dynamics, Giovani L. Vasconcelos, J. J. P. Veerman Jan 1999

Geometrical Models For Grain Dynamics, Giovani L. Vasconcelos, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

We study models for the gravity-driven, dissipative motion of a single grain on an inclined rough surface. Imposing some conditions on the momentum loss due to the collisions between the particle and the surface, we arrive at a class of models in which the grain dynamics is described by one-dimensional maps. The dynamics of these maps is studied in detail. We prove the existence of various dynamical phases and show that the presence of these phases is independent of the restitution law (within the class considered).

Go to article

On 2-Reptiles In The Plane, Sze-Man Ngai, Víctor F. Sirvent, J. J. P. Veerman, Yang Wang Jan 1999

On 2-Reptiles In The Plane, Sze-Man Ngai, Víctor F. Sirvent, J. J. P. Veerman, Yang Wang

Mathematics and Statistics Faculty Publications and Presentations

We classify all rational 2-reptiles in the plane. We also establish properties concerning rational reptiles in the plane in general.

Go to article

Soliton Stability In A Z (2) Field Theory, J. J. P. Veerman, D. Bazeia, Fernando Moraes Jan 1999

Soliton Stability In A Z (2) Field Theory, J. J. P. Veerman, D. Bazeia, Fernando Moraes

Mathematics and Statistics Faculty Publications and Presentations

We investigate the stability of the coupled soliton solutions of a two-component Z(2) vector fieldmodel, in contraposition to similar solutions of a Z(2)×Z(2)model recently introduced. We demonstrate that the coupled soliton solutions of the Z(2) model are classically unstable.

Go to article

Next Last