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.

Users Association in Ultra Dense THz Networks

Abstract: In this paper, we formulate a novel throughput aware user association scheme for ultra dense terahertz (THz) networks. In more detail, we introduce a user association problem, which takes into account the THz channel particularities, the directivity of the BSs' and UEs' antennas, as well as their position and the UEs' minimum rate requirements. Moreover, we provide the solution framework, which is based on the grey wolf optimizer (GWO) and returns the optimal user association table. Finally, we present comparative simulation results, which validate the superiority of the proposed framework against the commonly-used particle swarm optimizer (PSO) approach.

Software-Based Self-Testing of Symmetric Shared-Memory Multiprocessors

Abstract: Software-based or instruction-based self-testing has recently emerged as an effective alternative for the manufacturing and online testing of microprocessors, and is progressively adopted by major microprocessor manufacturers mainly as a supplement to other mature and well-established testing approaches to reach higher test quality. Thus far, software-based self-test approaches presented in the literature have focused almost exclusively on uniprocessors. With the continuing prevalence of multiprocessors, the focus of such research approaches moves from the uniprocessor to the multiprocessor case. In this paper, we study the application of software-based self-testing on symmetric shared-memory multiprocessors (SMP) considering the most common interconnection architectures, shared bus and crossbar switch. We focus on the impact of the shared-memory system architecture, the cache coherence mechanisms, and the interconnection architecture on the execution time of self-test programs running on each separate core and exploit the SMP's parallelism during testing to reduce the test execution time. We propose a generic methodology that allocates the test programs and test responses into the shared on-chip memory and schedules the test routines among the cores aiming at the reduction of the total test application time, and thus, test cost, for the SMP, by increasing the execution parallelism and reducing both bus contentions and data cache invalidations. We demonstrate the proposed solutions with detailed experiments on several two-core, four-core, and eight-core SMP benchmarks based on a popular RISC benchmark processor using both the shared bus and the crossbar switch interconnection architectures.

Old Wine in a New Bottle: Growth Convergence Dynamics in the EU

Abstract: In this paper, we explore convergence of real per capita output across the European Union (EU) countries, as well as the transitional behavior of possible underlying factors that are responsible for any convergence or divergence pattern The new panel convergence methodology developed by Phillips and Sul (2007) is employed in a production function growth accounting approach and data from the Total Economy Database and the Total Economy Growth Accounting Database The empirical findings suggest that the EU countries form two distinct convergent clubs, exhibiting considerable heterogeneity in the underlying growth factors These findings should help policy makers in designing appropriate growth-oriented programs as well as in setting priorities in their implementation

Specifying Workflow Process Requirements for an Emergency Medical Service

Abstract: Recent trends in healthcare delivery have led to a gradual shift in the conceptualisation of healthcare information systems towards supporting healthcare processes in a more direct way. The move towards integrated and managed care, which requires designing healthcare processes around patient needs and incorporating efficiency considerations, has led to an increased interest in process-oriented healthcare information systems based on workflow technology. This means to actively deliver the tasks to be performed to the right persons at the right time with the necessary information and the application functions needed. Moreover, workflow technology promotes a component-oriented development whereby the process logic is separated from application logic. This paper presents an approach to capturing process logic requirements for healthcare workflow systems with a view to design a system that is easily adjustable to process changes and to evolving organizational structures at a reasonable cost.