Parcourir par auteur "Lampsas, P."
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Agent placement in wireless embedded systems: Memory space and energy optimizations
Tziritas, N.; Loukopoulos, T.; Lalis, S.; Lampsas, P. (2010)Embedded applications can be structured in terms of mobile agents that are flexibly installed on available nodes. In wireless systems, such nodes typically have limited battery and memory resources; therefore it is important ... -
Algorithms for energy-driven agent placement in wireless embedded systems with memory constraints
Tziritas, N.; Loukopoulos, T.; Lalis, S.; Lampsas, P. (2011)The agent programming paradigm provides an easy to use framework for coding embedded applications in a pervasive environment. Under this model, applications are structured as mobile agents that can be flexibly installed ... -
Continuous replica placement schemes in distributed systems
Loukopoulos, T.; Lampsas, P.; Ahmad, I. (2005)The Replica Placement Problem (RPP) aims at creating a set of duplicated data objects across the nodes of a distributed system in order to optimize certain criteria. Typically, RPP formulations fall into two categories: ... -
Distributed Online Algorithms for the Agent Migration Problem in WSNs
Tziritas, N.; Lalis, S.; Khan, S. U.; Loukopoulos, T.; Xu, C. Z.; Lampsas, P. (2013)The mobile agent paradigm has been adopted by several systems in the area of wireless sensor networks as it enables a flexible distribution and placement of application components on nodes, at runtime. Most agent placement ... -
Formal model and scheduling heuristics for the replica migration problem
Tziritas, N.; Loukopoulos, T.; Lampsas, P.; Lalis, S. (2008)Replication of the most popular objects is often used in distributed data provision systems to reduce access time and improve availability. In fact, a given replica placement scheme may have to be redefined as object ... -
GRAL: A grouping algorithm to optimize application placement in wireless embedded systems
Tziritas, N.; Loukopoulos, T.; Lalis, S.; Lampsas, P. (2011)Recent embedded middleware initiatives enable the structuring of an application as a set of collaborating agents deployed in the various sensing/actuating entities of the system. Of particular importance is the incurred ... -
Implementation and Integration of Regional Health Care Data Networks in the Hellenic National Health Service
Lampsas, P.; Vidalis, I.; Papanikolaou, C.; Vagelatos, A. (2002)Background: Modern health care is provided with close cooperation among many different institutions and professionals, using their specialized expertise in a common effort to deliver best-quality and, at the same time, ... -
Implementing replica placements: Feasibility and cost minimization
Loukopoulos, T.; Tziritas, N.; Lampsas, P.; Lalis, S. (2007)Given two replication schemes Xold and Xnew, the Replica Transfer Scheduling Problem (RTSP) aims at reaching Xnew, starting from Xold, with minimal implementation cost. In this paper we generalize the problem description ... -
Improved genetic algorithms and list scheduling techniques for independent task scheduling in distributed systems
Loukopoulos, T.; Lampsas, P.; Sigalas, P. (2007)Given a set of tasks with certain characteristics, e.g., data size, estimated execution time and a set of processing nodes with their own parameters, the goal of task scheduling is to allocate tasks at nodes so that the ... -
Improving application availability in wireless sensor networks with energy-harvesting capability
Rentifis, I.; Tziritas, N.; Lampsas, P.; Lalis, S.; Loukopoulos, T. (2012)We assume a wireless sensor and actuator network with nodes that can harvest energy from the environment, and an application deployed in this network, which is structured as a set of cooperating mobile components that can ... -
Introducing agent evictions to improve application placement in wireless distributed systems
Tziritas, N.; Lampsas, P.; Lalis, S.; Loukopoulos, T.; Khan, S. U.; Xu, C. Z. (2012)With the development of mobile code frameworks for embedded systems, an application can be structured as a set of cooperating components (agents) that are placed on the nodes of the system in a flexible way. Reducing the ... -
Investigating the replica transfer scheduling problem
Loukopoulos, T.; Tziritas, N.; Lampsas, P.; Lalis, S. (2006)The Replica Placement Problem (RPP) aims at selecting the nodes for duplicating data objects in order to optimize their access. Even though a lot of work already exists on RPP, the issue of implementing the resulting ... -
Middleware mechanisms for agent mobility in wireless sensor and actuator networks
Tziritas, N.; Georgakoudis, G.; Lalis, S.; Paczesny, T.; Domaszewicz, J.; Lampsas, P.; Loukopoulos, T. (2012)This paper describes middleware-level support for agent mobility, targeted at hierarchically structured wireless sensor and actuator network applications. Agent mobility enables a dynamic deployment and adaptation of the ... -
On deploying tree structured agent applications in networked embedded systems
Tziritas, N.; Loukopoulos, T.; Lalis, S.; Lampsas, P. (2010)Given an application structured as a set of communicating mobile agents and a set of wireless nodes with sensing/actuating capabilities and agent hosting capacity constraints, the problem of deploying the application ... -
Scheduling independent tasks in heterogeneous environments under communication constraints
Lampsas, P.; Loukopoulos, T.; Dimopoulos, F.; Athanasiou, M. (2006)With the advent of the Grid, task scheduling in heterogeneous environments becomes more and more important. Of particular interest is the fact that especially in scientific experiments a non negligible amount of data must ... -
Scriptable virtual onboard sensors for conducting post-deployment drills in wireless sensor networks
Koutsoubelias, M.; Lalis, S.; Grigoropoulos, N.; Lampsas, P.; Katsikas, S.; Dimas, D. (2015)Wireless sensor networks (WSNs) can be extensively tested, before being deployed, using simulators and testbeds. However, it is equally important to be able to test a WSN system after it has been deployed, to verify that ... -
Single and Group Agent Migration: Algorithms, Bounds, and Optimality Issues
Tziritas, N.; Khan, S. U.; Loukopoulos, T.; Lalis, S.; Xu, C. Z.; Lampsas, P. (2014)Recent embedded middleware platforms enable the structuring of an application as a set of collaborating agents deployed on various nodes of the underlying wireless sensor network (WSN). Of particular importance is the ... -
Using multicast transfers in the replica migration problem: Formulation and scheduling heuristics
Tziritas, N.; Loukopoulos, T.; Lampsas, P.; Lalis, S. (2009)Performing replica migrations in the minimum possible time, also called the Replica Migration Problem (RMP), is crucial in distributed systems using replication. In this paper we tackle RMP when multicast transfers are ...