University of Piraeus

About: University of Piraeus is a education organization based out in Piraeus, Attiki, Greece. It is known for research contribution in the topics: Context (language use) & Computer science. The organization has 1731 authors who have published 6209 publications receiving 106699 citations.

On the Double-Generalized Gamma Statistics and Their Application to the Performance Analysis of V2V Communications

Abstract: Important statistical properties of the double-generalized Gamma (dGG) distribution are studied in this paper The dGG distribution is suitable for modeling non-homogeneous double-scattering radio propagation fading conditions, which can be frequently observed in vehicle-to-vehicle (V2V) communications In this context, important statistical metrics for the bivariate dGG distribution, such as the joint probability density function, cumulative distribution function, and the moments, are derived for the first time, while simplified expressions for the corresponding marginal statistical metrics are presented Moreover, the second-order statistics of this distribution are also analytically studied The derived analytical framework has been employed to analyze the performance of a transmit antenna selection system operating in V2V communication channels modeled by the dGG distribution In this scenario, the impact of outdated channel state information (CSI) to the system’s performance is investigated in terms of various metrics, including the level crossing rate and the average fade duration Furthermore, simplified asymptotic closed-form expressions for the outage probability have been derived to examine the achievable diversity and coding gains Based on our analysis, insightful discussions are provided It is shown that the diversity gain is independent from the number of transmit antennas when the available CSI becomes outdated

The Consolidation of European Stock Exchanges

Abstract: With the growing appeal of cross-border trading in Europe, efforts are under way to establish consolidated exchanges that offer trading in stocks from many European countries. An analysis of these evolving pan-European exchanges suggests that consolidation could reduce the costs and complications of cross-border trading through such enhancements as a standardization of trading platforms. Yet regulatory, legal, and economic barriers to the creation of these exchanges may delay any benefits of consolidation.

Re-examining Bitcoin Volatility: A CAViaR-based Approach

Abstract: The article aims to explore the heterogeneous feature in the determination of Bitcoin volatility using a Markov regime-switching model and test its forecasting ability. The forecasting methodology ...

Performance Analysis of Multi-Hop Amplify-and-Forward Relaying Systems in Rayleigh Fading Channels with a Poisson Interference Field

Abstract: In this paper, we analyze the performance of multi-hop transmission systems that employ amplify-and-forward relays over a Rayleigh fading environment in the presence of a Poisson field of interferers. The interference model considers the effect of spatial distribution of co-channel interferers in the vicinity of the relays and the destination node. Using a tight upper bound on the end-to-end signal-to-interference ratio, a closed-form expression for the system outage probability is derived. Moreover, a lower bound for the average symbol error rate of general modulations, the exact average bit error rate (BER) of binary modulations and the average channel capacity are presented in the form of single-fold integrals that can be reliably evaluated numerically, whereas closed-form results are obtained for a special case of the dual-hop relaying system. Finally, asymptotic expressions for the system outage probability and the end-to-end BER are derived which provide useful insights regarding the factors affecting the performance of the considered system. The novel expressions can be used to show the impact of interference model parameters such as the transmit power, path loss exponent, and spatial density of interferers on the performance of multi-hop wireless systems. Simulation results are further provided to demonstrate the accuracy of the analytical expressions.