2,101 research outputs found

    Theoretical Biomimetics: A biological design-driven concept for creative problem-solving as applied to the optimal sequencing of active learning techniques in educational theory

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    The article introduces the author’s concept of applying principles of biological design to drive creative problem-solving. It provides a brief background of the field of Biomimetics, which serves as a context for the reader to appreciate how it began with an established field upon which he constructed and adapted his concept to apply to human-made intangibles. A discussion of Theoretical Biomimetics specifies the differences between it and its predecessor. The final section provides the opportunity to see Theoretical Biomimetics in detail applied to education theory to address a problem related to student learning in higher education and how best to establish optimized sequences to implement evidence-based active-learning techniques to fill a void in the literature demonstrating from nature what has worked. The originality lies in the author taking a multidisciplinary approach to synergize a sequence of existing active-learning techniques and apply them to a new area in a new way

    A Comprehensive Definition of Technology from an Ethological Perspective

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    Definitions, uses, and understanding of technology have varied tremendously since Jacob Bigelow’s Elements of Technology in 1829. In addition to providing a frame of reference for understanding technology, the purpose of this study was to define or describe it conceptually. A determination of dimensions comprising technology was made by critiquing historical and contemporary examples of definition by Bigelow and Volti. An analytic-synthetic method was employed to deconstruct both definitions spanning two centuries to derive aspects of technology. Definitions relying on an anthropocentric “how humans use technology” viewpoint failed to account for different perspectives that were found when an ethological perspective inquiring “how technology is used” served as a framework. Findings support qualification of insulin as technology according to the following comprehensive definition: something inherently intelligent enough to either function, be used to function, or be interpreted as having a function that intelligent beings—human or otherwise—can appreciate, something devised, designed (by primary intention), or discovered (by secondary intention) serving particular purposes from a secular standpoint without humankind creating it, or a significant beneficiary of rationally derived knowledge that is “used for” a purpose without itself necessarily being translated into something material that “does” autonomously, or dependently when used

    A Minimal Type II Seesaw Model

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    We propose a minimal type II seesaw model by introducing only one right-handed neutrino besides the SU(2)LSU(2)_{L} triplet Higgs to the standard model. In the usual type II seesaw models with several right-handed neutrinos, the contributions of the right-handed neutrinos and the triplet Higgs to the CP asymmetry, which stems from the decay of the lightest right-handed neutrino, are proportional to their respective contributions to the light neutrino mass matrix. However, in our minimal type II seesaw model, this CP asymmetry is just given by the one-loop vertex correction involving the triplet Higgs, even though the contribution of the triplet Higgs does not dominate the light neutrino masses. For illustration, the Fritzsch-type lepton mass matrices are considered.Comment: 5 pages, 4 figures, some points clarified, useful references added, to appear in Phys. Rev.

    Possible Deviation from the Tri-bimaximal Neutrino Mixing in a Seesaw Model

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    We propose a simple but suggestive seesaw model with two phenomenological conjectures: three heavy (right-handed) Majorana neutrinos are degenerate in mass in the symmetry limit and three light Majorana neutrinos have the tri-bimaximal mixing pattern V0V^{}_0. We show that a small mass splitting between the first generation and the other two generations of heavy Majorana neutrinos is responsible for the deviation of the solar neutrino mixing angle θ12\theta^{}_{12} from its initial value 35.335.3^\circ given by V0V^{}_0, and the slight breaking of the mass degeneracy between the second and third generations of heavy Majorana neutrinos results in a small mixing angle θ13\theta^{}_{13} and a tiny departure of the atmospheric neutrino mixing angle θ23\theta^{}_{23} from 4545^\circ. It turns out that a normal hierarchy of the light neutrino mass spectrum is favored in this seesaw scenario.Comment: RevTex 12 pages (2 EPS figures included). More discussions and references adde

    Spin-orbit scattering in quantum diffusion of massive Dirac fermions

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    Effect of spin-orbit scattering on quantum diffusive transport of two-dimensional massive Dirac fermions is studied by the diagrammatic technique. The quantum diffusion of massive Dirac fermions can be viewed as a singlet Cooperon in the massless limit and a triplet Cooperon in the large-mass limit. The spin-orbit scattering behaves like random magnetic fields only to the triplet Cooperon, and suppresses the weak localization of Dirac fermions in the large-mass regime. This behavior suggests an experiment to detect the weak localization of bulk subbands in topological insulator thin films, in which a narrowing of the cusp of the negative magnetoconductivity is expected after doping heavy-element impurities. Finally, a detailed comparison between the conventional two-dimensional electrons and Dirac fermions is presented for impurities of orthogonal, symplectic, and unitary symmetries.Comment: 5 pages, 3 figures, 2 tables. To be submitted, comments are welcom

    Deduction of Pure Spin Current from Spin Linear and Circular Photogalvanic Effect in Semiconductor Quantum Wells

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    We study the spin photogalvanic effect in two-dimensional electron system with structure inversion asymmetry by means of the solution of semiconductor optical Bloch equations. It is shown that a linearly polarized light may inject a pure spin current in spin-splitting conduction bands due to Rashba spin-orbit coupling, while a circularly polarized light may inject spin-dependent photocurrent. We establish an explicit relation between the photocurrent by oblique incidence of a circularly polarized light and the pure spin current by normal incidence of a linearly polarized light such that we can deduce the amplitude of spin current from the measured spin photocurrent experimentally. This method may provide a source of spin current to study spin transport in semiconductors quantitatively

    Non-Classical Stress Concentration Behavior in a Radically Stretched Hyperelastic Sheet Containing a Circular Hole

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    Non-classical stress concentration behavior in a stretched circular hyperelastic sheet (outer radius b = 10 in., thickness t = 0.0625 in.) containing a central hole (radius a = 0.5 in.) was analyzed. The hyperelastic sheet was subjected to different levels of remote radial stretchings. Nastran large-strain large-deformation analysis and the Blatz-Ko large deformation theory were used to calculate the equal-biaxial stress concentration factors K. The results show that the values of K calculated from the Blatz-Ko theory and Nastran are extremely close. Unlike the classical linear elasticity theory, which gives the constant K = 2 for the equal-biaxial stress field, the hyperelastic K values were found to increase with increased stretching and can exceed the value K = 6 at a remote radial extension ratio of 2.35. The present K-values compare fairly well with the K-values obtained by previous works. The effect of the hole-size on K-values was investigated. The values of K start to decrease from a hole radius a = 0.125 in. down to K = 1 (no stress concentration) as a shrinks to a = 0 in. (no hole). Also, the newly introduced stretch and strain magnification factors {K(sub ),K(sub ) } are also material- and deformation-dependent, and can increase from linear levels of {1.0, 4.0} and reaching {3.07, 4.61}, respectively at a remote radial extension ratio of 2.35

    Fuzzy automata as coalgebras

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    The coalgebraic method is of great significance to research in process algebra, modal logic, object-oriented design and component-based software engineering. In recent years, fuzzy control has been widely used in many fields, such as handwriting recognition and the control of robots or air conditioners. It is then an interesting topic to analyze the behavior of fuzzy automata from a coalgebraic point of view. This paper models different types of fuzzy automata as coalgebras with a monad structure capturing fuzzy behavior. Based on the coalgebraic models, we can define a notion of fuzzy language and consider several versions of bisimulation for fuzzy automata. A group of combinators is defined to compose fuzzy automata of two branches: state transition and output function. A case study illustrates the coalgebraic models proposed and their composition.This work has been supported by the Guangdong Science and Technology Department (Grant No. 2018B010107004) and the National Natural Science Foundation of China under grant No. 61772038, 61532019 and 61272160. L.S.B. was supported by the ERDF—European Regional Development Fund through the Operational Programme for Competitiveness and InternationalisationCOMPETE 2020 Programme and by National Funds through the Portuguese funding agency, FCT, within project KLEE - POCI-01-0145-FEDER-030947

    Place-based correlates of Motor Vehicle Theft and Recovery: Measuring spatial influence across neighbourhood context

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    Social scientists have long shown great interest in the spatial correlates of crime patterns. A subset of the literature has focused on how micro-level spatial factors influence the formation of crime hot spots. At the same time, tangential research has highlighted how neighbourhood disadvantage influences crime occurrence. The current study focuses on the intersection of these perspectives through a spatial analysis of Motor Vehicle Theft (MVT) and Motor Vehicle Recovery (MVR) in Colorado Springs, CO. We begin by conducting a Risk Terrain Modelling analysis to identify spatial risk factors significantly related to MVT and MVR occurrence. We then test whether the spatial influences of the criminogenic risk factors differ across traditional measures of neighbourhood disadvantage. Findings suggest that while a citywide effect is evident for multiple risk factors, their spatial influence on crime significantly varies across neighbourhood contexts
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