oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 1 )

2019 ( 7 )

2018 ( 15 )

2017 ( 11 )

Custom range...

Search Results: 1 - 10 of 3026 matches for " Dennis The "
All listed articles are free for downloading (OA Articles)
Page 1 /3026
Display every page Item
Contact Geometry of Hyperbolic Equations of Generic Type
Dennis The
Symmetry, Integrability and Geometry : Methods and Applications , 2008,
Abstract: We study the contact geometry of scalar second order hyperbolic equations in the plane of generic type. Following a derivation of parametrized contact-invariants to distinguish Monge-Ampère (class 6-6), Goursat (class 6-7) and generic (class 7-7) hyperbolic equations, we use Cartan's equivalence method to study the generic case. An intriguing feature of this class of equations is that every generic hyperbolic equation admits at most a nine-dimensional contact symmetry algebra. The nine-dimensional bound is sharp: normal forms for the contact-equivalence classes of these maximally symmetric generic hyperbolic equations are derived and explicit symmetry algebras are presented. Moreover, these maximally symmetric equations are Darboux integrable. An enumeration of several submaximally symmetric (eight and seven-dimensional) generic hyperbolic structures is also given.
Invariant Yang-Mills connections over Non-Reductive Pseudo-Riemannian Homogeneous Spaces
Dennis The
Physics , 2007, DOI: 10.1090/S0002-9947-09-04797-7
Abstract: We study invariant gauge fields over the 4-dimensional non-reductive pseudo-Riemannian homogeneous spaces G/K recently classified by Fels & Renner (2006). Given H compact semi-simple, classification results are obtained for principal H-bundles over G/K admitting: (1) a G-action (by bundle automorphisms) projecting to left multiplication on the base, and (2) at least one G-invariant connection. There are two cases which admit nontrivial examples of such bundles and all G-invariant connections on these bundles are Yang-Mills. The validity of the principle of symmetric criticality (PSC) is investigated in the context of the bundle of connections and is shown to fail for all but one of the Fels-Renner cases. This failure arises from degeneracy of the scalar product on pseudo-tensorial forms restricted to the space of symmetric variations of an invariant connection. In the exceptional case where PSC is valid, there is a unique G-invariant connection which is moreover universal, i.e. it is the solution of the Euler-Lagrange equations associated to any G-invariant Lagrangian on the bundle of connections. This solution is a canonical connection associated with a weaker notion of reductivity which we introduce.
Contact Geometry of Hyperbolic Equations of Generic Type
Dennis The
Mathematics , 2008, DOI: 10.3842/SIGMA.2008.058
Abstract: We study the contact geometry of scalar second order hyperbolic equations in the plane of generic type. Following a derivation of parametrized contact-invariants to distinguish Monge-Ampere (class 6-6), Goursat (class 6-7) and generic (class 7-7) hyperbolic equations, we use Cartan's equivalence method to study the generic case. An intriguing feature of this class of equations is that every generic hyperbolic equation admits at most a nine-dimensional contact symmetry algebra. The nine-dimensional bound is sharp: normal forms for the contact-equivalence classes of these maximally symmetric generic hyperbolic equations are derived and explicit symmetry algebras are presented. Moreover, these maximally symmetric equations are Darboux integrable. An enumeration of several submaximally symmetric (eight and seven-dimensional) generic hyperbolic structures is also given.
Conformal geometry of surfaces in the Lagrangian--Grassmannian and second order PDE
Dennis The
Mathematics , 2010, DOI: 10.1112/plms/pdr023
Abstract: Of all real Lagrangian--Grassmannians $LG(n,2n)$, only $LG(2,4)$ admits a distinguished (Lorentzian) conformal structure and hence is identified with the indefinite M\"obius space $S^{1,2}$. Using Cartan's method of moving frames, we study hyperbolic (timelike) surfaces in $LG(2,4)$ modulo the conformal symplectic group $CSp(4,R)$. This $CSp(4,R)$-invariant classification is also a contact-invariant classification of (in general, highly non-linear) second order scalar hyperbolic PDE in the plane. Via $LG(2,4)$, we give a simple geometric argument for the invariance of the general hyperbolic Monge--Amp\`ere equation and the relative invariants which characterize it. For hyperbolic PDE of non-Monge--Amp\`ere type, we demonstrate the existence of a geometrically associated ``conjugate'' PDE. Finally, we give the first known example of a Dupin cyclide in a Lorentzian space.
General Theory of Economics: CDR Supply Side Scientific Growth Law Unveiled  [PDF]
Dennis Ridley
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.815223
Abstract: The capitalism (C), democracy (D) and rule of law (R)CDR global invariant hypothesis was previously demonstrated for year 2014 cross country per capita real gross domestic product adjusted for purchasing power parity (G). Consistent with the principle of parsimony, the CDR index explained G with only these three variables. This paper re-estimates the model for the last 22 years of available data. The result is model parameters that are a set of global time invariant constants. These constants constitute the global time invariant CDR index defined by the vector inner (dot) product of the global constants and country C, D, R and C·D·R. This establishes the CDR global time invariant hypothesis. Exogenous and endogenous components of capital are decoupled to calculate and explain the values and roles of new ideas versus old capital stock. Based on the unitary entrepreneurship elasticity of G, the theoretical optimal reinvestment in capital stock is validated by empirical gross fixed capital formation. Together, these place economic growth on a scientific basis. Because of the absence of explicit definitions in the extant literature for concepts such as capitalist, capitalism, entrepreneurship and other consequential terminologies, they are clarified in concise nomenclature.
Urban Vulnerabilities in the Kathmandu Valley, Nepal: Visualizations of Human/Hazard Interactions  [PDF]
Keshav Bhattarai, Dennis Conway
Journal of Geographic Information System (JGIS) , 2010, DOI: 10.4236/jgis.2010.22012
Abstract: Excessive unplanned urban growth leads to many vulnerabilities and impacts on urban environments to varying degrees. However, the majority of the extant literature focuses on the problems related to location and socioeconomic conditions, rather than vulnerability processes and related environmental degradation. This paper analyzes the scope of urban vulnerabilities for five rapidly urbanizing and highly-congested cities in the Kathmandu Valley, Nepal. First, the historic context of the Valley’s uncontrolled urbanization sets the scene. Second, the optic is narrowed to focus upon the geographical features of the resultant urbanized Valley landscape that includes spatial arrangements and of houses, population densities, road networks, vehicular densities, garbage problems, and available open spaces. Additionally, seismic vulnerabilities in the urban areas are also considering in this examination. Third, three-dimensional visualizations of selected urban locations are presented to differentiate between vulnerable and relatively safe locations. The intent of this research is to contribute to the methodological understanding of human/hazards interactions in rapidly urbanizing cities of the Third World, which share similar socioeconomic conditions and environmental con-texts.
The Use of Life Narrative and Living Standard Measurement Survey Data in the Study of Poverty in the Caribbean: A Resolution of Conflicting Epistemologies  [PDF]
Dennis A. V. Brown
Sociology Mind (SM) , 2013, DOI: 10.4236/sm.2013.33030
Abstract:

The paper examines the compatibility or usefulness of fit between epistemologically disparate quantitative survey data and qualitative life narrative data gleaned in the study of poverty in the Caribbean. It aims to find out whether or not the different approaches to the understanding of reality on which the two methodologies are based preclude the integration of their findings as a means of furthering understanding of the dynamics of Caribbean poverty. The analysis draws on Country Poverty Studies conducted in the territory of Grenada in the Eastern Caribbean. It is centered on the demographic measure of fertility, a measure of chronic illnesses by socioeconomic status and life narrative interviews conducted around the themes of poverty, family and life experiences with select poor households across the country. Fertility was measured using parity of women aged <15 - 30+. Statistical analyses were done using cross tabulations. The findings indicate that the hermeneutic understanding of the life narratives, and the causal explanatory accounts provided by the positivist quantitative data, allow for understanding of negative health seeking behaviour on the part of the poor, not provided by the quantitative data by themselves. They also provide insight into the synergy between family, reproductive behaviour, labour market status and chronic poverty in the Caribbean region that would not have been possible through the use of the positivist quantitative method by itself.

Social Pressure on Patient Decision Making through Shifting Mental Models: Presenting Evidence to Patients  [PDF]
Dennis J. Mazur
Sociology Mind (SM) , 2015, DOI: 10.4236/sm.2015.52010
Abstract: In humans, the processes of thinking or making decisions are usually based on mental models. Some of these mental models are designed to represent how humans think and decide, while others aim to improve their thinking and decision making. In decision making related to a patient’s health and medical care, high courts aim to protect the patient’s right to be involved in this process, while societal forces attempt to control costs associated with health and medical decision making. This paper examines legal, decision making, and social theories regarding the societal forces that attempt to influence the grounds upon which a patient thinks and decides about his or her health and medical care.
General Theory of Antithetic Time Series  [PDF]
Pierre Ngnepieba, Dennis Ridley
Journal of Applied Mathematics and Physics (JAMP) , 2015, DOI: 10.4236/jamp.2015.312197
Abstract: A generalized antithetic time series theory for exponentially derived antithetic random variables is developed. The correlation function between a generalized gamma distributed random variable and its pth exponent is derived. We prove that the correlation approaches minus one as the exponent approaches zero from the left and the shape parameter approaches infinity.
A Routine Activity Approach: Assessing Victimization by Gender in Transit Environments and Other Public Locations  [PDF]
Dennis M. Savard
Advances in Applied Sociology (AASoci) , 2018, DOI: 10.4236/aasoci.2018.81004
Abstract: The purpose of this research is to examine how transit environments and other public spaces shape women’s and men’s victimization for simple assault, aggravated assault, sexual assault, robbery, and kidnapping crimes. This research applies routine activities theory to examine how everyday activities shape victimization within these environments. Using data from the Federal Bureau of Investigations’ 2014 National Incident-Based Reporting System, this research finds that women were more likely to be victimized in certain spaces such as shopping centers and transit terminals. Regarding certain violent crimes, it was also discovered that women were more likely to be robbed at shopping centers, grocery stores, parking lots/garages, and transit terminals. It is argued that understanding the vulnerability of simple assault, aggravated assault, sexual assault, robbery, and kidnapping victimization women have in transit environments and other public spaces may provide useful insight regarding preventing crime in these locations.
Page 1 /3026
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.