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.

Secure, Green Implementation of Modular Arithmetic Operations for IoT and Cloud Applications

Abstract: In this chapter, methods for securely performing the calculations required for fundamental modular arithmetic operations, namely multiplication and exponentiation using mobile, embedded, remote or distant computational resources, are proposed that offer the possibility for green information processing system development. These methods are targeted to the distributed paradigms of cloud computing resources and Internet of Things applications. They provide security by avoiding the disclosure to the cloud resource of either the data or the user secret key. Simultaneously, environmental effects of processing are minimized by the simplifications of the operations and by transferring demanding calculations to energy efficient data centers. Hence the proposed methods are also shown to serve the green IT engineering paradigm. An algorithm for the software implementation of modular multiplication is proposed, which uses pre-computations with a constant modulus to reduce the computational load imposed upon the processor. The developed modular multiplication algorithm provides faster execution on low complexity hardware in comparison with the existing algorithms and is oriented towards the variable value of the modulus, especially with the software implementation on micro controllers and smart cards whose architectures include a small number of bits. The proposed technique for modular exponentiation is based on performing simple operations on the user computational resources, shifting the remaining complex operations to high performance, energy-efficient cloud resources and operates by separating the procedure for modular exponentiation in two components. Security is maintained by maintaining the purpose-specific secret key information exclusively in user resources. The details of the pre-calculation of the secret keys are described. Hence the procedure for transferring the most demanding part of the calculation to the cloud resources is given. It is therefore shown that a potential attacker receives no information by intercepting the data existing in the cloud. The overall process is illustrated by a simple numerical example. The use of the new algorithm in Information Society applications that demand security is investigated. Such applications include e-Government, e-Banking, e-Commerce etc. The algorithm is shown to be adequate both for the applications for which it was originally intended, as well as for applications that are much more demanding in the level of security they require, such as military applications.

Towards Multispectral Multimodal Non-ionising Diagnosis and Therapy

Abstract: As the boundary between biology, medicine, and engineering remains indistinct, electromagnetics engineering applications are expanding to encapsulate a variety of public health issues. Medical applications of microwaves are a very rapidly developing research and application field, especially for intracranial applications. Currently, in order to acquire the most valuable complementary data in terms of quality and quantity, benefiting from the advantages of the various techniques, combination of two or more techniques is pursued both in diagnostics and therapy. The so-called multimodal approach may be achieved either by post-session analysis of data or via simultaneous use of techniques in order to reveal the multifactorial interplay of the underlying mechanisms during brain activation, disease and therapy. This chapter will review the progress in diagnostic, therapeutic and theranostic multi-modal multispectral methods, with specific attention to cerebrovascular diseases and monitoring of the brain activity.

Hopf hypersurfaces in pseudo-Riemannian complex and para-complex space forms

Abstract: The study of real hypersurfaces in pseudo-Riemannian complex space forms and para-complex space forms, which are the pseudo-Riemannian generalizations of the complex space forms, is addressed. It is proved that there are no umbilic hypersurfaces, nor real hypersurfaces with parallel shape operator in such spaces. Denoting by J be the complex or para-complex structure of a pseudo-complex or para-complex space form respectively, a non-degenerate hypersurface of such space with unit normal vector field N is said to be Hopf if the tangent vector field JN is a principal direction. It is proved that if a hypersurface is Hopf, then the corresponding principal curvature (the Hopf curvature) is constant. It is also observed that in some cases a Hopf hypersurface must be, locally, a tube over a complex (or para-complex) submanifold, thus generalizing previous results of Cecil, Ryan and Montiel.

Non-smooth bending and buckling of a strain gradient elastic beam with non-convex stored energy function

Abstract: Non-smooth strain gradient fields are studied in bending beams, in the context of strain gradient elasticity. It is found that strain fields with continuous curvature, but discontinuous curvature derivatives (evolutes) are possible. The pure bending and buckling problems of a simply supported beam are investigated.