Omiros Ragos

Effects in the anomalistic period of celestial bodies due to a logarithmic correction to the Newtonian gravitational potential

We study the motion of a secondary celestial body under the influence of the logarithmic corrected gravitational force of a primary one. This kind of correction was introduced by Fabris and Campos (Gen. Relativ. Gravit. 41(1):93, 2009). We derive two equations to compute the rate of change of the anomalistic period with respect to the eccentric anomaly and its total variation over one revolution. In a kinematical sense, this influence produces an apsidal motion. We perform numerical estimations for some celestial bodies. We also compare our results to those obtained by considering a Yukawa correction.

Kretschmann Invariant and Relations Between Spacetime Singularities Entropy and Information

Curvature invariants are scalar quantities constructed from tensors that represent curvature. One of the most basic polynomial curvature invariants in general relativity is the Kretschmann scalar. This study is an investigation of this curvature invariant and the connection of geometry to entropy and information of different metrics and black holes. The scalar gives the curvature of the spacetime as a function of the radial distance r in the vicinity as well as inside of the black hole. We derive the Kretschmann Scalar (KS) first for a fifth force metric that incorporates a Yukawa correction, then for a Yukawa type of Schwarzschild black hole, for a Reissner-Nordstrom black hole and finally an internal star metric. Then we investigate the relation and derive the curvature’s dependence on the entropy S and number of information N. Finally we discuss the settings in which the entropy’s full range of positive and negative values would have a meaningful interpretation. The Kretschmann scalar helps us understand the black hole’s appearance as a whole entity. It can be applied in solar mass size black holes, neutron stars or supermassive black holes at the center of various galaxies.

Quantum and post-Newtonian effects in the anomalistic period and the mean motion of celestial bodies

We study the motion of a secondary celestial body under the influence of the corrected gravitational force of a primary. We study the effect of quantum and relativistic corrections to the gravitational potential of a primary body acting on the orbiting body. More specifically, two equations are derived to approximate the perigee/perihelion/periastron time rate of change and its total variation over one revolution (i.e., the difference between the anomalistic period and the Keplerian period) under the influence of the quantum as well as post-Newtonian accelerations. Numerical results have been obtained for the artificial Earth satellite GRACE-A, Mercury, and, finally, the for the HW Vir c, planetary companion.

Role Modeling of IoT services in industry domains

In this paper, we describe our ongoing work on modeling services in industry domains. Nowadays, many large software systems that are developed for industry are mainly built from services. Yet, modeling services and their interaction still remain a challenging task. Moreover, new emerged technologies such as cloud computing, Internet of Things (IoT), microservices, smart factories and Cyber Physical Systems (CPS) create additional concerns and need to be integrated into existing models. This imposes a change to the monolithic architectures used to model service interaction and cooperation.n In this work, we argue that modeling interaction of services can be handled more effectively by modeling services with the role modeling (RM) approach. Afterwards, we aim to exploit the modeling features and formally present the RM diagrams to using a logic system where we will be able to reason over the composition of services in industry domains.

Radar Signal Delay in the Dvali-Gabadadze-Porrati Gravity in the Vicinity of the Sun

In this paper we examine the recently introduced Dvali-Gabadadze-Porrati (DGP) gravity model. We use a space-time metric in which the local gravitation source dominates the metric over the contributions from the cosmological flow. Anticipating ideal possible solar system effects, we derive expressions for the signal time delays in the vicinity of the Sun. and for various ranges of the angle θ of the signal approach, The time contribution due to DGP correction to the metric is found to be proportional to b3/2/c2r0. For r0 equal to 5xa0Mpc and θ in the range [−π/3,π/3], Δt is equal to 0.0001233xa0ps. This delay is extremely small to be measured by today’s technology but it could be probably measurable by future experiments.