Results 11 to 20 of about 2,096,695 (356)
Maximum Principles for Null Hypersurfaces and Null Splitting Theorems [PDF]
Annales Poincare Phys.Theor. 1 (2000) 543-567, 1999 A maximum principle for C^0 null hypersurfaces is obtained and used to derive a splitting theorem for spacetimes which contain null lines. As a consequence of this null splitting theorem, it is proved that an asymptotically simple vacuum (Ricci flat) spacetime which contains a null line is isometric to Minkowski space.
Galloway, Gregory J.
arxiv +3 more sources
Null Killing vectors and geometry of null strings in Einstein spaces [PDF]
Gen. Relativ. Gravit. (2014) 46: 1714, 2013 Einstein complex spacetimes admitting null Killing or null homothetic Killing vectors are studied. These vectors define totally null and geodesic 2-surfaces called the null strings or twistor surfaces. Geometric properties of these null strings are discussed.
Chudecki, Adam
arxiv +5 more sources
The appearance, motion, and disappearance of three-dimensional magnetic null points [PDF]
arXiv, 2015 While theoretical models and simulations of magnetic reconnection often assume symmetry such that the magnetic null point when present is co-located with a flow stagnation point, the introduction of asymmetry typically leads to non-ideal flows across the null point.
Andrew L. Haynes +6 more
arxiv +5 more sources
A Model for Effective Accountability at Public Universities: Mixed Method [PDF]
پژوهش در نظامهای آموزشی, 2019 The purpose of this study was to investigate experts' perceptions and attitudes towards various aspects of public universities accountability in Tehran city. This study used an exploratory mixed methods approach involving 309 faculty members, experts and
abbas abbaspour +3 more
doaj +1 more source
The Functions of Transcendental Ego in Kant's Epistemology [PDF]
حکمت و فلسفه, 2019 Kant's transcendental ego is the absolute and final subject which constitutes the logical foundation of knowledge and experience. It is completely subjective, and as the most necessary and fundamental element in Kant's epistemology is involved in any ...
null null, behzad hassanpour
doaj +1 more source
A Formalization of SQL with Nulls [PDF]
Journal of Automated Reasoning, 2022 AbstractSQL is the world’s most popular declarative language, forming the basis of the multi-billion-dollar database industry. Although SQL has been standardized, the full standard is based on ambiguous natural language rather than formal specification.
Wilmer Ricciotti, James Cheney
openaire +3 more sources
Face recognition using fine-tuning of Deep Convolutional Neural Network and transfer learning [PDF]
مجله مدل سازی در مهندسی, 2019 Deep learning is one of the most important scopes of the Machine Learning that includes some important architectures. Deep Convolutional Neural Network is one of the attractive architectures that uses in digital image processing.
Razieh Rastgoo, kourosh kiani
doaj +1 more source
Psychological / social and perceptual / motor ergonomics of intelligent classes with students' health [PDF]
مطالعات روانشناسی تربیتی, 2019 Objective of this survey is to evaluate the mental-social and conceptual-kinetic ergonomic relationship of smart classes with students’ health. Its statistical population is all girl and boy students of grade six in primary schools who were studying in ...
alireza badele, Fahimeh Al-Sadat Sahebi
doaj +1 more source
Search for Physics beyond the Standard Model at the Tevatron [PDF]
, 2006 Recent searches for physics beyond the standard model at the Tevatron are reported, with emphasis on supersymmetry.Comment: to appear in Proceedings of SUSY06, the 14th International Conference on Supersymmetry and the Unification of Fundamental ...
Jean-François Grivaz +2 more
core +4 more sources
Capabilities and Challenges of Virtual Social Networking for Iranian Civil Society [PDF]
مطالعات رسانههای نوین, 2019 This paper identifies the capacities and challenges of virtual social networks in the development of civil society in Iran and the attitudes of civil activists in Tehran about them. This study was a blended method and its method was deep interviewing and
yousef khojir, hadi khaniki
doaj +1 more source