508 research outputs found
The Δρομοδείχτης της Ελλάδος of 1824 and Athanasios Stageirites (Τίτλος περίληψης)
No full textσ. [281]-290Κείμενο στα ελληνικά με περίληψη στα αγγλικά με τον τίτλο: The Δρομοδείχτης της Ελλάδος of 1824 and Athanasios StageiritesThe article first examines the close relationship between the publication “Δρομοδείχτης της Ελλάδος” [1824] and the publication “Ηπειρωτικά” (1819) by Athanasios Stageirites and then suggests that Athanasios Stageirites is the likeliest author of the “Δρομοδείχτης της Ελλάδος”.Δωδώνη: Τεύχος Πρώτο: επιστημονική επετηρίδα του Τμήματος Ιστορίας και Αρχαιολογίας της Φιλοσοφικής Σχολής του Πανεπιστημίου Ιωαννίνων; Τόμ. 43-44 (2014-2015
Dataset in support of the Southampton doctoral thesis 'The boatbuilding tradition of the Aegean during the Late Neolithic – Early Bronze Age periods. Typological classification, digital reconstruction and seakeeping assessment'
No full textDataset in support of the Southampton doctoral thesis 'The boatbuilding tradition of the Aegean during the Late Neolithic – Early Bronze Age periods. Typological classification, digital reconstruction and seakeeping assessment' Appendix D - Resistance data and Appendix C - Stability data.
This dataset is focused on two appendices:
Appendix D - Resistance data. D.1 Resistance data produced by the author via MAXSURF Resistance for this thesis.
Appendix C - Stability data
C1. Stability data – STIX and ISO criteria, produced by the author via MAXSURF Stability software for his thesis
This research was funded by Southampton Marine and Maritime Institute (SMMI), Vice-Chancellor's Scholarship, Greek Archaeological Committee UK (GACUK)
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Critical points and trajectories of the Bohmian quantum flow
No full textIn the present work we study the critical points of the Bohmian quantum flow, namely the nodal point and its associated X-point, which are responsible for the generation of chaos in Bohmian trajectories. In the first part of the paper we find an analytical equation for the position of the X-point in a planar 2-d Bohmian system with a single nodal point and test its accuracy numerically. We then calculate its asymptotic curves and comment on the way they affect the evolution of the nearby Bohmian trajectories. In the second part we present our first results on the position of the X-point and its asymptotic curves in a 3d partially integrable system, where the Bohmian trajectories evolve on spherical surfaces
Chaos in 2-d Bohmian Trajectories
No full textWe make a short review of the most general mechanism for the generation of chaos in 2-d Bohmian trajectories, the so called `nodal point-X-point complex' (NPXPC) mechanism. The presentation is based on numerical calculations made with Maple and is enriched with new results on the details of the generation of chaos, and the form of the potential around the NPXPC
A comparison between classical and Bohmian quantum chaos
No full textWe study the emergence of chaos in a 2d system corresponding to a classical Hamiltonian system consisting of two interacting harmonic oscillators and compare the classical and the Bohmian quantum trajectories for increasing values of . In particular we present an initial quantum state composed of two coherent states in and , which in the absence of interaction produces ordered trajectories (Lissajous figures) and an initial state which contains {both chaotic and ordered} trajectories for . In both cases we find that, in general, Bohmian trajectories become chaotic in the long run, but chaos emerges at times which depend on the strength of the interaction between the oscillators.19 figure
Peak power reduction algorithms in asymmetric digital subscriber line modems
No full textThesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (leaves 94-96).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.This thesis investigates peak-to-average ratio (PAR) reduction techniques for multicarrier modulation systems, such as discrete multitone (DMT) modems and orthogonal frequency-division multiplexed (OFDM) terrestrial broadcast transmitters. Through simulation and test implementation on a state-of-the-art programmable ADSL development platform, this thesis pursues a suitable solution for minimizing PAR given the resources of a programmable platform. This solution is integrated as a prototype implementation into a fully-functional ADSL modem and optimized for maximum PAR reduction performance within modem complexity constraints.by Athanasios Dimitri Dousis.M.Eng
Classical and Bohmian Trajectories in Integrable and Nonintegrable Systems
No full textIn the present paper, we study both classical and quantum Hénon–Heiles systems. In particular, we make a comparison between the classical and quantum trajectories of integrable and nonintegrable Hénon–Heiles Hamiltonians. From a classical standpoint, we study both theoretically and numerically the form of invariant curves in the Poincaré surfaces of section for several values of the coupling parameter in the integrable case and compare them with those in the nonintegrable case. Then, we examine the corresponding Bohmian trajectories, and we find that they are chaotic in both cases, but with chaos emerging at different times
Dynamics of quantum observables and Born's rule in Bohmian Quantum Mechanics
No full textWe investigate both ordered and chaotic Bohmian trajectories within the Born
distribution of Bohmian particles of an anisotropic 2d quantum harmonic
oscillator. We compute the average values of energy, momentum, angular
momentum, and position using both Standard Quantum Mechanics and Bohmian
Mechanics. In particular, we examine realizations of the Born distribution for
a wavefunction with a single nodal point and two different wavefunctions with
multiple nodal points: one with an almost equal number of ordered and chaotic
trajectories, and another composed primarily of chaotic trajectories.
Throughout our analysis, we focus on elucidating the contribution of ordered
and chaotic Bohmian trajectories in determining these average values.Comment: 19 pages, 14 figure
Unstable Points, Ergodicity and Born’s Rule in 2d Bohmian Systems
No full textWe study the role of unstable points in the Bohmian flow of a 2d system composed of two non-interacting harmonic oscillators. In particular, we study the unstable points in the inertial frame of reference as well as in the frame of reference of the moving nodal points, in cases with 1, 2 and multiple nodal points. Then, we find the contributions of the ordered and chaotic trajectories in the Born distribution, and when the latter is accessible by an initial particle distribution which does not satisfy Born’s rule
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