Keynotes

Helen D. Karatza, Aristotle University of Thessaloniki, Greece "Scheduling in Grid Systems"

Abstract

Scheduling and resource management in complex heterogeneous distributed systems, such grids, became more important due to the increase of users and applications.

Computational and data grids are the most common grid types. In this talk we focus on computational grids, which are used for serving demanding and complex tasks.

Because of the nature of grids, there are important issues that must be addressed, such as efficient scheduling and load balancing.

Grid scheduling manages the selection of resources for a job, the allocation of jobs to resources and the monitoring of jobs execution. In a grid system where two different job types exist, grid jobs and local jobs, scheduling becomes much more challenging.

Scheduling algorithms usually have to deal with two issues: queue ordering and resource assignment. Queue ordering refers to the order in which jobs are assigned to resources and resource assignment refers to the selection of resources on which each job is assigned.

A grid system following a hierarchical architecture is organized at multiple levels. For example, at the grid level, a grid scheduler selects the appropriate sites for jobs, and at the in-site local level, local schedulers allocate jobs to specific resources.

Effective load distribution is of great importance at grids as it results to lower response times of jobs and fairness in utilization among the heterogeneous sites. Load balancing algorithms can be static or dynamic.

The performance evaluation of grid systems is often possible only by simulation rather than by analytical techniques, due to the complexity of the systems. Simulation can provide important insights into the efficiency and tradeoffs of scheduling in large-scale heterogeneous distributed systems, such as grids.  

Bio

Helen Karatza is an associate professor in the Department of Informatics at the Aristotle University of Thessaloniki, Greece. Her research interests include Computer Systems Modeling and Simulation, Performance Evaluation of Parallel and Distributed Systems, Resource Allocation and Scheduling, Cluster Computing, Grid Computing, Real-time Distributed Systems and P2P Systems.
Dr. Karatza is a Senior member of: IEEE, ACM and SCS (The Society for Computer Simulation International). She is Editor-in-Chief of the journal Simulation Modeling Practice and Theory (Elsevier).

Nik Bessis, University of Bedfordshire, UK "Using Next Generation Grid Technologies for Advancing Virtual Organizations"

Abstract

Computer-based developments over the last years have facilitated decision makers and problem solvers with numerous computational tools to support operational, tactical, and strategic levels of enquiry via the formation of collaborative virtual organizations.
Current ITs are capable of supporting collaborative activities in the cyberspace. These cyber-enabled collaborations involve the emergence of multiple organizations that function as one unit through the use of their shared resources for the purpose of one or more identified goals. This cluster of collaborative organizations functioning as a unit towards an identified goal lasts for the lifetime of the identified goal. The fact that such collaboration is happening in cyberspace and that it has a transient life labels it as a virtual organization.
On the other hand, the rapid developments in networking and resource integration domains have resulted in the emergence and in some instances to the maturation of distributed and collaborative paradigms such as Web Services, P2P, Grid and Cloud computing, data mashups and Web 2.0.
During the last ten years, scientists have almost exclusively used these technologies for their own research and development purposes. Most of these developments are focused on developing the platforms and the communication and networking infrastructures for solving very complex problems.
In this talk, the focus is shifting to more interdisciplinary application domains as possibly there is no better time to discuss about the inter-cooperation between virtual organizations using the ‘critical friend’ concept. The enabling nature of these technologies allows us to visualize the collaborative and synergetic use of next generation technology paradigms in a less conventional manner, which are currently problem focused.
Specifically, current Web and Web 2.0 implementations and future manifestations will store and continuously produce a vast amount of distributed data, which if combined and analyzed through a collective and computational intelligence manner using next generation data technologies will make a difference in the virtual organizational setting and their user communities, which they cater for.

Bio

DR. BESSIS IS CURRENTLY A PRINCIPAL LECTURER (ASSOCIATE PROFESSOR) IN THE DEPARTMENT OF COMPUTER SCIENCE AND TECHNOLOGY AT UNIVERSITY OF BEDFORDSHIRE (UK). HE OBTAINED A BA (1991) FROM THE TEI OF ATHENS AND COMPLETED HIS MA (1995) AND PHD (2002) AT DE MONTFORT UNIVERSITY (LEICESTER, UK).

HIS RESEARCH INTEREST IS THE ANALYSIS, RESEARCH, AND DELIVERY OF USER-LED DEVELOPMENTS WITH REGARD TO DATA INTEGRATION, DATA ANNOTATION, AND DATA PUSH METHODS AND SERVICES IN COLLABORATIVE AND APPLIED DISTRIBUTED ENVIRONMENTS. THESE HAVE A PARTICULAR FOCUS ON THE STUDY AND USE OF NEXT GENERATION AND DATA GRID TECHNOLOGIES FOR THE BENEFIT OF VARIOUS VIRTUAL ORGANIZATIONAL SETTINGS. HE IS INVOLVED IN (£2M) AND LEADING (£0.5M) A NUMBER OF FUNDED RESEARCH AND COMMERCIAL PROJECTS IN THESE AREAS.

HE HAS WIDELY PUBLISHED CHAPTERS, PAPERS AND ARTICLES IN BOOKS, INTERNATIONAL CONFERENCES AND JOURNALS, AND HE IS ALSO EDITOR OF BOOKS AND THE FOUNDING EDITOR-IN-CHIEF OF THE INTERNATIONAL JOURNAL OF DISTRIBUTED SYSTEMS AND TECHNOLOGIES (IJDST). HE IS A REGULAR REVIEWER OF SEVERAL JOURNALS AND CONFERENCES AND SERVES IN THE EDITORIAL BOARD OF SEVERAL INTERNATIONAL JOURNALS AS AN ASSOCIATE EDITOR. FINALLY, HE SERVES AS A SCIENTIFIC PROGRAM COMMITTEE MEMBER, A SESSION CHAIR AND A PROGRAME CHAIR AND/OR CO-CHAIR IN NUMEROUS INTERNATIONAL CONFERENCES.