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.

Adaptive Antenna Subarray Formation for MIMO Systems

Abstract: MIMO systems with reduced hardware complexity have attracted researchers' attention due to their high efficiency and low cost. Sub-optimum algorithms for antenna subset selection have been intensively studied in the literature. In this paper we present a new technique to maximize the capacity of multiple antenna wireless systems with reduced available RF chains. The technique is based on the adaptive formation of subarrays, i.e. the grouping of antenna elements and the application of appropriate element weights. The elements of each subarray and their weights are dynamically selected by an evolutionary optimization technique using the link capacity as a cost function

Cascading Effects of Common-Cause Failures in Critical Infrastructures

Abstract: One of the most challenging problems in critical infrastructure protection is the assessment and mitigation of cascading failures across infrastructures. In previous research, we have proposed a model for assessing the cumulative security risk of cascading threats due to high-order dependencies between infrastructures. However, recent empirical studies indicate that common-cause failures may result in extremely high impact situations, which may be comparable with or even more devastating than the cascading effects of high-order dependencies. This paper presents an extension to our model, which permits the assessment of the risk arising from complex situations involving multiple cascading failures triggered by major or concurrent common-cause events. The paper also discusses a realistic scenario that is used as a test case for the model extension.

The relationship between foreign direct investment and economic growth: evidence from transition countries

Abstract: This paper examines the importance of foreign direct investment on economic growth. Using a panel data set for 27 transition economies over the period 1991–2004 as well as the methodology of panel cointegration and causality tests, the empirical findings show that foreign direct investment does exhibit a significant relationship with economic growth, at least for those transition countries that are characterized by high levels of income and have implemented successful privatization programs.