CRIS - former TEI of Epirushttp://cris.teiep.gr/jspuiThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Fri, 30 Jul 2021 16:45:17 GMT2021-07-30T16:45:17Z5041A solution of the 4th clay millennium problem about the Navier-Stokes equations.http://cris.teiep.gr/jspui/handle/123456789/1628Title: A solution of the 4th clay millennium problem about the Navier-Stokes equations.
Authors: Kyritsis, Konstantinos
Abstract: In this paper it is solved the 4th Clay Millennium problem about the Navier-Stokes equations, in the direction of regularity. It is done so by utilizing the hypothesis of finite initial energy and by applying the regularity of the Poisson equation which is a well- studied linear PDE, involving the also well studies harmonic functions. The Poisson equation either in scalar or vector form, relates many magnitudes of the flow, like pressures and velocities, velocity and vorticity and velocities and viscosity forces. It is also proved 5 new necessary and sufficient conditions of regularity based on the pressures, viscosity forces, trajectories lengths, pressure forces etc. The final key result to derive the regularity is that the pressures are bounded in finite time intervals, as proved after projecting the work of the pressures forces on specially chosen bundles of paths.
Sun, 25 Feb 2018 00:00:00 GMThttp://cris.teiep.gr/jspui/handle/123456789/16282018-02-25T00:00:00ZOptimal portfolio selection of securities in the Athens Stock-Exchance during 2011-2016.http://cris.teiep.gr/jspui/handle/123456789/1630Title: Optimal portfolio selection of securities in the Athens Stock-Exchance during 2011-2016.
Authors: Kyritsis, Konstantinos; Koutsoukis, Thomas D.; Gikas, Grigorios; Arnis, Nikolaos
Abstract: Σε αυτό το άρθρο, εφαρμόζουμε δύο μεθόδους για τη βέλτιστη επιλογή χαρτοφυλακίων μετοχών του
Χρηματιστηρίου Αθηνών κατά την περίοδο 2011-2016. Η πρώτη είναι η πολύ γνωστή μέθοδος του Warren
Buffett, βασισμένη σε θεμελιώδη ανάλυση, και η δεύτερη είναι αρχικά θεμελιώδης ανάλυση για τη μείωση
του αριθμού των τίτλων σε διαχειρίσιμο πλήθος για υπολογισμούς, και στη συνέχεια η πολύ γνωστή μέθοδος
cut-off rate of single index market στο πλαίσιο της θεωρίας χαρτοφυλακίων του Markowitz.
Description: Conference proceedings pp 122-136 https://books.google.gr/books?isbn=6188298024
Mon, 05 Mar 2018 00:00:00 GMThttp://cris.teiep.gr/jspui/handle/123456789/16302018-03-05T00:00:00ZData envelopment analysis (DEA) for efficiency assessment of the best use of information systems in Greek Stock-Excanche brokerageshttp://cris.teiep.gr/jspui/handle/123456789/1629Title: Data envelopment analysis (DEA) for efficiency assessment of the best use of information systems in Greek Stock-Excanche brokerages
Authors: Kyritsis, Konstantinos; Reklitis, Panagiotis; Chytis, Evangelos
Abstract: In this paper we analyze data from Greek stock-exchange brokerage companies, with the method of Data Envelopment Analysis (DEA) so as to assess the utilization and the effect of the relevant ERP modules for the production of financial services. It is discussed both the appropriate conceptual models for the value of the IT systems, and also the managerial recommendations to the companies for improving the efficiency of the utilization.
Description: Conference proceedings in https://books.google.gr/books?isbn=6188298024 pp 137-147
Mon, 05 Mar 2018 00:00:00 GMThttp://cris.teiep.gr/jspui/handle/123456789/16292018-03-05T00:00:00ZThe new digital mathematics of the millenniumhttp://cris.teiep.gr/jspui/handle/123456789/1684Title: The new digital mathematics of the millennium
Authors: Kyritsis, Konstantinos
Abstract: This project is under the next philosophical principles
1) Consciousness has the experience of the infinite.
2) But the physical material world is finite.
3) Therefore mathematical models in their ontology should contain only finite entities and should not involve the infinite at all which is a phenomenological abstraction. In digital mathematics we may have the concepts of seemingly infinite sets (or seemingly infinitesimal numbers) but they are essentially finite sets or numbers with finite decimal representation.
These principles allow for an alternative and more realistic universe of mathematics, directly usable in artificial intelligence of computers. The development of digital mathematics is somehow more elaborate in the definitions but radically easier in the proofs compared to classical mathematics. It is certainly not equivalent to the classical mathematics. But here we give emphasis only to the theorems that are very similar and very familiar with corresponding to classical mathematics.
The previous principles require a rewriting of the classical axiomatic systems to those of
1) the natural digital numbers,
2) the digital 1st and 2nd order formal logic,
3) the digital set theory,
4) the digital real numbers,
5) the digital differential and integral calculus,
6) the digital Euclidean axiomatic continuous geometry
etc.
In the next two papers we present the digital real numbers with the digital differential and integral calculus and the digital axiomatic continuous Euclidean geometry, where all sets of points (visible or invisible) or numbers are finite sets of points and numbers with finite decimal representation.
Our perception and experience of the reality, depends on the system of beliefs that we have. In mathematics, the system of spiritual beliefs is nothing else than the axioms of the axiomatic systems that we accept. The rest is the work of reasoning and acting.
For each of the two papers we give at its end a fictional philosophical or epistemological dialogue with the celebrated immortals of the classical mathematics (like Euclid, Pythagoras, Hilbert, Cantor, Gödel, Newton, Leibniz etc) where the reader can grasp in non-technical terns the main differences and the main advantages (or disadvantages) of the digital mathematics where all are finite compared to the classical mathematics which are based on the phenomenological abstraction of the infinite
The 2nd of the two papers on the digital but continuous axiomatic Euclidean geometry has already been published in the World Journal of Research and Review (WJRR)ISSN:2455-3956, Volume-5, Issue-4, October 2017 Pages 31-43
Wed, 20 Feb 2019 00:00:00 GMThttp://cris.teiep.gr/jspui/handle/123456789/16842019-02-20T00:00:00Z