Hellenic Military Academy

About: Hellenic Military Academy is a education organization based out in Voula, Greece. It is known for research contribution in the topics: Complex space & Jacobi operator. The organization has 36 authors who have published 97 publications receiving 541 citations.

Influence of an External DC Electric Current on Plasma Cleaning Rate: an Application on the Enlarged Plasma-Surface Theory

Abstract: During the last decades many researchers have been occupied with other plasma applications apart from the big challenge which the thermonuclear fusion poses. Many experiments have been carried out on the plasma behavior in contact with a solid surface; when the surface material consists of chemical compounds (e.g. oxides of metals), then the plasma chemistry takes place. The present paper contains the final experimental and theoretical work of Plasma Laboratory at "Demokritos", which consists of an elaboration of plasma sheath parameters adapted to experimental conditions, a suitable choice of plasma gases (either H2 or N2), and an electric potential current enforcement on objects. Additionally, a brief theory is given to explain the results, with a short reference to both boundary phenomena in thermonuclear reactors and low pressure plasma of glow discharges, so as to reveal the similarities and differences of these two cases. An extensive examination of the treated objects by X-ray diffraction method (XRD) gives results in agreement with the theoretical predictions. Using this improvement on plasma restoration system, (a combination of electric current on metallic object into suitable plasma), it is shown that better results can be achieved on the cleaning and conservation of archaeological objects.

Generalized Padé-type approximants to continuous functions

Abstract: We define generalized Pade-type approximants to continuous functions on a compact subset Eof Rnsatisfying the Markov's inequality and we show that the Fourier series expansion of a generalized Pade-type approximant to a u ∈ C ∞(E ) matches the Fourier series expansion of uas far as possible. After studying the errors, we give integral representations and an answer to the convergence problem of a generalized Pade-type approximation sequence.

Combination of cost effective 3D scanning techniques for the development of web virtual museums

Abstract: The increase of the speed of broadband internet and the need of the museums for an attractive and impressive way of online presentation of their artifacts guide the IT companies to a search for cost effective 3D scanning techniques. The 3D scanning Techniques, which were evaluated, were topographic, photogrammetric and photo based model creation techniques. Using as a case study the museum of "Pontian Hellenism" at the building of "The Committee For Pontian Studies", with a specific budget which includes the 3D Scanning and the development of the web virtual museum, the above techniques were tested on field. The result of the evaluated techniques was a series of guidelines of which method of 3D Scanning is better to be used in cases of developing web virtual museum.

Modeling Cyber-Security

Abstract: This paper documents a holistic mathematical modeling theory to provide a rigorous description of cyber-attacks and cyber-security. After determining valuations and vulnerabilities of parts of a node constituent, we recall the definitions of cyber-effect and cyber-interaction. Based on these concepts, we give the mathematical definitions of cyber navigation and infected node and we explain what is meant by dangerous cyber navigation and protection of cyber nodes from unplanned attacks. Our discussion proceeds to a rigorous description of passive and active cyber-attacks, as well as the relevant protections.

Synchronization Error Correction for Asynchronous Channels Data Transmission

Abstract: Loss of synchronization is a common source of errors in asynchronous data channels. Minute differences in the operating frequencies between the transmitter and the receiver result in data bits being lost or false bits being inserted. This paper presents an innovative technique, especially designed for detecting and correcting errors of this type. Data packets are preprocessed and areas that are susceptible to are determined. Suitable redundancy is introduced in the form of control symbols. On the receiver side, similar calculations take place and decisions are made on the occurrence and positions of the transmission errors due to loss of synchronization, which are hence corrected. The proposed method is computationally simple, since it uses a small number of simple mathematical operations, contrary to existing, general purpose techniques. The transmission overheads it imposes do not vary significantly from existing error control codes. Additionally, the number of errors that may be corrected is not subject to the same limits as existing techniques.