Besides Colloquiums, the Department of Computer Science at the University of Cyprus also holds Other Presentations
(Research Seminars, PhD Defenses, Short Term Courses, Demonstrations,
etc.). These presentations are given by scientists who aim to present
preliminary results of their research work and/or other technical
material. Other Presentations serve as a forum for educating Computer
Science students and related announcements are disseminated to the
Department of Computer Science (i.e., the csall list):
Subscribe to the Other Presentations RSS feed (copy the below URL into your favorite RSS reader) | Colloquiums | Other Presentations |
Other Presentations held by the Department
Course Lecture: Robust Implementations of Atomic Read/Write Objects in Message-Passing Systems, Dr. Chryssis Georgiou (University of Cyprus), Tuesday, March 23th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Robust Implementations of Atomic Read/Write Objects in Message-Passing Systems
Speaker: Dr. Chryssis Georgiou
Affiliation: University of Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Tuesday, March 23th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
Data survivability is undoubtedly essential in today's systems and applications. The only way
to ensure survivability of data is through redundancy: the data is replicated and maintained at
several network locations. Replication introduces the challenge of maintaining consistency
among the replicas despite system asynchrony and failures. Doing so efficiently, makes this
task even more challenging.
We investigate this challenging problem by studying efficient implementations of atomic read/write
sharable objects in asynchronous message-passing systems. An atomic read/write object allows
concurrent processes to share information through a common variable, as if they were accessing
this variable in a sequential manner. This abstraction, usually referred as atomic register, is
fundamental in distributed computing and is at the heart of a large number of distributed algorithms.
The object is replicated to several failure-prone server processes and failure-prone reader and writer
client processes perform read and write operations by communicating with the servers. We are
particularly interested in wait-free implementations of atomic registers, where any read or write
operation by any non-faulty client eventually completes, despite of the operational status of the
other clients. The efficiency of such implementations is expressed with the read/write operation
latency which is measured by the number of communication rounds required between clients
and servers for each operation to complete.
In this talk, I will present the conditions under which wait-free implementations of SWMR and
MWMR atomic registers in asynchronous message-passing systems can be both efficient and
fault-tolerant. I will also demonstrate how such implementations (when possible) can be constructed.
Short Bio:
Chryssis Georgiou is an Assistant Professor in the Department of Computer Science at the
University of Cyprus. He holds a Ph.D. (December 2003) and M.Sc. (May 2002) in Computer
Science and Engineering from the University of Connecticut and a B.Sc. (June 1998) in
Mathematics from the University of Cyprus. He has worked as a Teaching and Research Assistant
at the University of Connecticut, USA (1998-2003) and as a Visiting Lecturer (2004) and a
Lecturer (2005-2008) at the University of Cyprus. His research interests span the Theory and Practice
of Fault-tolerant Distributed and Parallel Computing. He has published in top journals and conference
proceedings in his area of study and he has co-authored a book on Distributed Cooperative Computing.
He served on Program Committees of top conferences in Distributed Computing and he is on the
Steering Committee (2008-2010) of the International Symposium on Distributed Computing (DISC).
Personal website: http://www.cs.ucy.ac.cy/~chryssis
 |
Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
|
Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: The Implications of Cache-Content-Duplication on Shared Caches, Marios Kleanthous (University of Cyprus), Tuesday, March 16th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
The Implications of Cache-Content-Duplication on Shared Caches
Speaker: Marios Kleanthous
Affiliation: University of Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Tuesday, March 16th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
The importance of caches and memory hierarchy has increased over time due to
the growing gap between processor and memory performance. Caches,
consequently, have been central to numerous research studies. Several
techniques have been proposed to improve various aspects of caches by
reducing their miss rates, size, latency and energy. Most of these
techniques attempt to exploit different types of properties of memory
addresses and data, such as locality, predictability, and redundancy.
Previous work identified a new cache property that may influence cache
performance: the Cache-Content-Duplication (CCD). This phenomenon occurs
when there is a miss for a block in a cache and the content of the missed
block resides already in the cache in another block with a different
address.
This presentation will give an insight on the effects of CCD on instruction
caches and the hardware mechanism that detects and exploits CCD. Also, we
will examine the importance of CCD in shared caches which are now widely
used by modern Chip Multi-Processors (CMP) and Simultaneous Multi-Threading
(SMT) technology.
Short Bio:
Marios Kleanthous completed his undergraduate degree in the Department of
Informatics and Telecommunications at the National and Kapodistrian
University of Athens in 2004. The same year he started his M.Sc degree in
Computer Science at the University of Cyprus. In 2006 he completed his M.Sc
degree and became a Ph.D student under the supervission of Prof. Yiannakis
Sazeides. Currently, he is a Ph.D student in Computer Science Department at the
University of Cyprus and also a member of the Xi-Computer Architecture
Research Group where he works on the Cache Content Duplication Phenomenon.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Oracle Hands-On Tutorial, Norman Christopher (Oracle Corporation), Friday, March 19th, 2010, 12:00-13:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Oracle Hands-On Tutorial
Speaker: Norman Christopher
Affiliation: Oracle Corporation
Category: Course Lecture
Location: Room B121, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Friday, March 19th, 2010
Time: 12:00-13:30 EET
Host: George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
This talk will cover the following topics: Oracle Overview. Database Market Position. Architectural Overview.
Installation. Tutorial/Demo (Enterprise Manager, Creating a Session, DDL & DML in SQL).
Short Bio:
Norman Christopher is principal consultant in Oracle Corporation. Experience: 19 Years, Oracle Database and ERP Applications technical and functional principal consultant. Skill Set: Applications analysis & development, Senior Oracle DBA (Versions 5,6,7,8, 9i, 10&11g), fluent on windows and all flavors of Unix. Software: Oracle Forms & Reports, C, PLSQL, Pro*C. Employment History Highlights: International Oracle Corporation - Principal Consultant: current employer (Four years), NCR Corporation - Senior IT Consultant (Five years), AT&T - IT Consultant, Local
Logicom Software Solutions - Oracle Department Manager (Four years), Globalsoft - Oracle Applications Technical Manager (Two years)
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Allocation and Admission Policies for Server Farms, Dr. Michelle Mazzucco (University of Cyprus), Friday, March 12th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Allocation and Admission Policies for Server Farms
Speaker: Michelle Mazzucco
Affiliation: University of Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Friday, March 12th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
As IT systems are becoming more and more important, one of the main concerns is that users may face major breakdowns and eventually incur major costs if computing systems do not meet the expected performance requirements: customers expect reliability and performance guarantees, while under-performing systems lose revenues. For example, it has been reported that Amazon tried delaying the page generation by 100 ms and found out that even very small delays would result in substantial and costly drops in revenue (1% sales drop for 100 ms delay).
In this talk I will discuss some performance models aiming at optimizing the revenue earned by IT providers running jobs subject to Quality of Service (QoS) constraints and present a middleware architecture for Web Service provision.
Experimental results show that revenues can be dramatically improved by imposing suitable conditions for accepting incoming traffic.
Short Bio:
Michele Mazzucco earned his BSc and MSc at the University of Bologna (Italy) in 2003 and 2005, and received his PhD from Newcastle University (UK) in 2009 (advisor Prof. Isi Mitrani) with a thesis on optimization problems in the context of commercial data centers.
From 2006 to 2008 he worked as a Research Associate at N'cle, funded by British Telecom (BT). He is currently a Marie Curie Fellow at the University of Cyprus.
|
Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
|
Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Adaptive Methods for the Transmission of Video Streams in Wireless Networks, Dr. Vasos Vassiliou (University of Cyprus), Tuesday, March 9th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Adaptive Methods for the Transmission of Video Streams in Wireless Networks
Speaker: Vasos Vassiliou
Affiliation: University of Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Tuesday, March 9th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
The task of a communication network is to provide traffic transportation services between end users by conveying data from one node to another in a reliable and timely fashion. This task means that a network is a shared entity; its services should not be dedicated to only a pair of communicating entities but to as many entities possible during its operational lifetime. Network planners have always strived to design networks that achieve high user capacities and high quality of service, but have always faced the same limitation: the finite amount of resources which a network has available for utilization in order to fulfill its task.
In this talk we will discuss the important issues that arise when trying to support video streams and other real-time multimedia applications over wireless networks. First we will illustrate the importance of applications' adaptability and QoS awareness in mobile wireless networks using as an example 3G cellular wireless networks. Then we will characterize the requirements of real-time multimedia applications and define the limitations of mobile wireless networks. Lastly, we will describe a new method for video stream adaptation based on Fuzzy Logic control, developed in the context of a UCY-funded research program.
Short Bio:
Dr. Vasos Vassiliou is a Lecturer at the Computer Science Department of the University of Cyprus since 2005. He is also the Associate Director of the Networks Research Laboratory (NetRL) at UCY. He held positions as a Visiting Lecturer at the same department (2004-2005) and as an Assistant Professor at the Computer Science Department of Intercollege (2002-2004). He has published several articles in International Conferences and Journals and participates actively in COST actions, local, and European Projects. His research interests include High Speed Network Architectures (MPLS), Mobile Networks (Mobile IP, MMPLS, Ad Hoc and Sensor Networks), Wireless Communications (Protocol enhancements for 3G/4G cellular wireless networks) and Quality of Service (QoS) and Traffic Engineering for computer and telecommunication networks. He holds an M.Sc. (1999) and a Ph.D. (2002) from the Georgia Institute of Technology both in Electrical and Computer Engineering. He is a member of IET (former IEE), IEEE, ACM, and participates in the Technical Program Committees of several international conferences, such as Globecom, VTC, PIMRC, WNET, EW. He is also an Associate Editor of the Journal of Telecommunication Systems.
|
Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
|
Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: GridStat Framework, Harald Gjermundrod (University of Nicosia, Cyprus), Friday, March 5th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
GridStat Framework
Speaker: Harald Gjermundrod
Affiliation: University of Nicosia, Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Friday, March 5th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
The North American power grids involve almost 3500 utility organizations. Existing SCADA-based status communication systems, which primarily use point-to-point links between substations and individual utility's control centers, provide inadequate cross-utility situational awareness for grid operators. The GridStat project is creating status dissemination middleware to allow creation of flexible, QoS-managed information infrastructures that address this problem for the power grid and other large, distributed infrastructures. The GridStat architecture naturally extends to nationwide, cross-infrastructure monitoring.
This talk will give an overview of the architecture and design of the GridStat framework. Three of its base line mechanisms will also be presented. The condensation function mechanism allows the users to subscribe to patterns of events and have the evaluation of these patterns be performed at the middleware layer. The mode change mechanism allows for rapid uninterrupted change of subscription sets within various regions of the infrastructure. The final mechanism to be presented is the Ratatoskr RPC that provides timeliness, redundancy, and safety properties over a Pub-Sub infrastructure.
Short Bio:
Harald Gjermundrod is currently an Assistant Professor of Computer Science at the University of Nicosia which he joined in September 2008 and an adjunct faculty at Washington State University. Prior to this he was an postdoctorate associate (2006-2008) at the High-Performance Computing Systems Laboratory in the Computer Science Department of the University of Cyprus.
His research interests include middleware, distributed computing systems, and Grid computing. Gjermundrod received his PhD, MS, and BS degrees in computer science from Washington State University in 2006, 2001, 1999 respectively and Dipl.-Ing degree from Oslo University College in 1998 (including a year as an Erasmus student at the Robert Gordon University). Gjermundrod has worked on projects funded by the EU, the National Institute of Technology(US), and the National Science Foundation(US).
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Data Parallel Acceleration of Decision Support Queries Using Cell/BE and GPUs, Pedro Trancoso (University of Cyprus, Cyprus), Tuesday, March 2nd, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Data Parallel Acceleration of Decision Support Queries Using Cell/BE and GPUs
Speaker: Pedro Trancoso
Affiliation: University of Cyprus, Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Tuesday, March 2nd, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
Decision Support System (DSS) workloads are known to be
one of the most time-consuming database workloads that
processes large data sets. Traditionally, DSS queries have
been accelerated using large-scale multiprocessor.
The topic addressed in this work is to analyze the benefits
of using high-performance/low-cost processors such as the
GPUs and the Cell/BE to accelerate DSS query execution.
In order to overcome the programming effort of developing
code for different architectures, in this work we explore the
use of a platform, Rapidmind, which offers the possibility of
executing the same program on both Cell/BE and GPUs.
To achieve this goal we propose data-parallel versions of the
original database scan and join algorithms.
In our experimental results we compare the execution of
three queries from the standard DSS benchmark TPC-H on
two systems with two different GPU models, a system with
the Cell/BE processor, and a system with dual quad-core
Xeon processors. The results show that parallelism can be
well exploited by the GPUs. The speedup values observed
were up to 21x compared to a single processor system.
Short Bio:
Pedro Trancoso received the undergraduate degree in electrical and
computer engineering from Instituto Superior Tecnico (IST), Technical
University of Lisbon, Lisbon, Portugal, in 1993, the MSc and PhD degrees
in computer science from the University of Illinois at Urbana-Champaign,
Illinois, U.S.A., in 1995 and 1998. He is currently an Assistant
Professor at the Department of Computer Science of the University of
Cyprus, Nicosia, Cyprus. He has worked at IBM T.J. Watson Research
Center, U.S.A. as a researcher (1997), at the University of Illinois at
Urbana-Champaign, U.S.A. as a visiting scholar (2000), and at
Intercollege Limassol, Cyprus as an assistant professor (1998-2001). He
has published several papers in the area of computer architecture, with
a focus on the memory hierarchy, intelligent memory technologies,
architecture-aware optimizations for database workloads and
benchmarking, power-performance efficient architectures, multi-core
architectures, and the use of graphics processors for general purpose
applications. He was a recipient of a Fulbright scholarship to pursue
his PhD studies, an EU-Mobility grant and a HPC-Europa grant to visit,
as a researcher, the Supercomputing Center CESCA-CEPBA at the
Universitat Politecnica de Catalunya, Barcelona, Spain, in 2002 and
2005. He is a member of the CoreGrid Network of Excellence, the IEEE and
ACM. He has been a member in the Program Committee of several
International Conferences including Parallel Architecture and
Compilation Techniques, PACT 2004, and Local-Chair of Topic 7 (Parallel
Computer Architecture and ILP) of EuroPar 2005. He is currently a member
of the Editorial Board for the International Journal of High-Performance
System Architecture. He is the head of the CASPER (Computer Architecture
and Systems Performance Evaluation Research) research group. His
research interest is in the area of computer architecture, with a focus
on the memory hierarchy, intelligent memory technologies,
architecture-aware optimizations for database workloads and
benchmarking, power-performance efficient architectures, multi-core
architectures, and the use of graphics processors for general purpose
applications.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Computational Intelligent Diagnostic Systems, Christos Schizas (University of Cyprus, Cyprus), Friday, February 26th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Computational Intelligent Diagnostic Systems
Speaker: Christos SchizasAffiliation: University of Cyprus, Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Friday, February 26th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
Theoretical applied studies of techniques for building useful intelligent
systems, something that has always been a goal of scientists and engineers.
Although Artificial Intelligence has been providing a shed to this for many
years, Computational Intelligence was restated in an effort to provide some
new links to human intelligence, and, therefore, some additional premises
and inspirations for building even smartest systems in more practical ways.
The backbone of Computational Intelligence is composed of relatively more
traditional areas such as artificial neural networks, fuzzy systems,
evolutionary computation, and genetic algorithms. The research work in this
area is outlines in four major groups: 1. Modeling Cognitive Systems; the
main purpose of this research activity is to use computational intelligence
techniques to develop systems that model several behaviors of the Brain
activity. In general, computational modeling can help to understand the
functional organization of a particular cognitive phenomenon, 2.
Computational modeling of visual selective attention; a computational model
of human visual selective attention has been implemented according to the
perspective of a systems engineer and computer scientist. The computational
model is biologically plausible and supports recent theories from the fields
of neuroscience and cognitive psychology. 3. Artificial Neural Network
Modeling; in Single Neuron Modeling, a generic neuronal model using a block
form of operational diagrams is investigated. The power of this
representation is determined by the fact that an easy identification and
extraction of the most essential features of single neuron models is
allowed. 4. Intelligent Applications; on the application side, computational
intelligent methods are investigated in many areas including, diagnostic and
prognostic systems in medicine, meteorological systems, engineering systems
design, electric load forecasting, and financial applications., and
intelligent applications.
Short Bio:
Christos N. Schizas
Professor of Computer Science, University of Cyprus. Received a B.Sc. degree
in electronic engineering from the University of London, UK, in 1978, M.B.A
degree from the University of Indianapolis, Indiana, in 1988, and Ph.D.
degree in systems theory from the University of London in 1981. He received
the 1979 William Lincoln Shelley award from the University of London for
excellence in research, and a Fulbright fellowship for collaborative
research in the USA in 1993. He was a Postdoctoral Fellow at the University
of London (1980-1983), and was Professor of Computer Information Systems at
the University of Indianapolis (1989-1991). Since 1991 he has been with the
Department of Computer Science, University of Cyprus. He served as Vice
Rector of the University of Cyprus (2002-2006). His research interests
include computational intelligence, medical informatics, diagnostic and
prognostic systems, system modelling and identification of brain activity.
He edited conference proceedings and served as associate editor of the
journal Technology and Health Care, area editor of the journal, IEEE
Transactions on Information Technology in Biomedicine, and member of the
editorial board of the journal, Intelligent Systems. He has published over
120 refereed journal and conference papers in these areas and supervised
researchers, PhD and MSc students. He is the founder of the Computational
Intelligence laboratory of the University of Cyprus. He has taken part in
European Commission initiatives for promoting the Information Society,
especially the Euro-Mediterranean partnership.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Usability of interactive systems: Current practices and challenges of its measurement, Panayiotis Zaharias (University of Cyprus, Cyprus), Tuesday, February 23th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Usability of interactive systems: Current practices and challenges of its measurement
Speaker: Panayiotis Zaharias
Affiliation: University of Cyprus, Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Tuesday, February 23th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
Usability is a core term in human-computer interaction (HCI).
The growing importance of usability evaluation of contemporary interactive information systems have
become evident in both researech and practice during the recent years.
The purpose of this lecture is to review current practice in how usability is measured and
to analyse problems with the measures of usability employed. Additionally this talk will present
the challenges to conducting usability studies and to research into how to measure usability.
Short Bio:
Panagiotis holds a Ph.D. degree in Information Systems (specialization on Human Computer Interaction, thesis title: A Usability Evaluation Method of E-learning Courses) from the Department of Management Science & Technology of Athens University of Economics and Business (2004). He received a first degree in Informatics from the Department of Informatics in Athens University of Economics and Business (1998), and a Masters degree in Information Systems from the MSc. Program in Information Systems in Athens University of Economics and Business (2000). His main research interests are focused on user experience, usability evaluation methods and e-Learning design. He has participated in various European and National-based research projects. He has published more than 30 papers in scientific journals and conference proceedings. He is a member of ACM Special Interest Group on Human-Computer Interaction (SIGCHI) and AACE (Association for the Advancement of Computing in Education) organization. He is currently a Visiting Lecturer at the Department of Computer Science at the University of Cyprus. He is also a research associate of IST lab/OIS Research Group of the Athens University of Economics and Business.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Keyword Search and Ranking in Relational Databases: Object Summaries, Georgios Fakas (Manchester Metropolitan University, UK and University of Cyprus, Cyprus), Friday, February 19th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Keyword Search and Ranking in Relational Databases: Object Summaries
Speaker: Georgios Fakas
Affiliation: Manchester Metropolitan University, UK and University of Cyprus, Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of
Pure and Applied Sciences, New Campus (map)
Date: Friday, February 19th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT
cs.ucy.ac.cy)
Abstract:
A novel Keyword Search paradigm in relational databases is proposed,where the result of a search is an Object Summary (OS). An OS
summarizes all data held about a particular Data Subject (DS) in a
database. More precisely, it is a tree with a tuple containing the
keyword(s) as a root and neighboring tuples as children. In contrast
to traditional Relational Keyword Search, an OS comprises a more
complete and therefore semantically meaningful set of information
about the enquired DS. The proposed paradigm introduces the concept of Affinity and
Importance in order to automatically generate OSs. More precisely, it
investigates and quantifies the Affinity of relations (i.e. Affinity)
and their attributes (i.e. Attributes Affinity) in order to decide
which tuples and attributes to include in the OS. A global Importance
score for each tuple of the database (denoted as Im(ti)) is
investigated and quantified. For this purpose, ValueRank, an extension
of ObjectRank, is introduced which incorporates also tuples' values in
authority flow and therefore facilitating the estimation of Importance
for arbitrary databases, e.g. trading databases etc.
Experimental evaluation on DBLP, TPC-H and Northwind databases
verifies the effectiveness and efficiency of our approach.
Short Bio:
Georgios Fakas is a Senior Lecturer at the Department of Computing and
Mathematics of the Manchester Metropolitan University, UK. Currently,
he is at the University of Cyprus under the "Hosting of Experienced
Researchers from Abroad" Programme of the Cyprus Research Promotion
Foundation (RPF). He also worked as a Research Associate at the
Institute for Automatic Control of the Swiss Federal Institute of
Technology - Lausanne (EPFL), Switzerland and at the Computer Science
Department of the University of Cyprus, Cyprus. He obtained his Ph.D.
in Computation in 1998 from the Department of Computation, UMIST,
Manchester, UK. His research interests include keyword search and
ranking in relational databases.
| Other Presentations Web: http://www.cs.uc y.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquiu m/ |
Course Lecture: Size Complexity of Two-Way Finite Automata, Christos Kapoutsis (University of Cyprus, Cyprus), Tuesday, February 16th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Size Complexity of Two-Way Finite Automata
Speaker: Christos Kapoutsis
Affiliation: University of Cyprus,
Cyprus
Category: Research Seminar
Location: Room 147, Building 12 Faculty of
Pure and Applied Sciences, New Campus (map)
Date: Tuesday, February 16th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract: This is a talk on the size complexity of two-way finite automata. We will present the central open
problem in the area, explain a motivation behind it, recall its early history, and introduce some of
the concepts used in its study. We will then sketch a possible future, describe a natural systematic
way of pursuing it, and record some of the progress that has been achieved so far. We will add
little to what is already known ---only exposition, terminology, and questions.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Rapid Creation of Photorealistic Large-Scale Urban City Models, Charis Poullis (University of Cyprus, Cyprus), Friday, February 12th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Rapid Creation of Photorealistic Large-Scale Urban City Models
Speaker: Charis Poullis
Affiliation: University of Cyprus,
Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of
Pure and Applied Sciences, New Campus (map)
Date: Friday, February 12th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
In recent years there has been an increasing demand for applications which
employ miniature representations of the real world to recreate realistic and immersive virtual
environments. Many applications ranging
from computer graphics and virtual reality, to Geographical Information
Systems have already successfully
used real world representations derived from the combination of multi-sensory
data captured from aerial or
satellite imagery and LiDAR(Light Detection and Ranging) scanners. However,
despite their widespread and successfull application, the creation of such realistic 3D content remains
a complex, time-consuming, expensive and labor-intensive task. In fact, the creation of models is still
widely viewed as a specialized art, requiring personnel with extensive training and experience to produce
useful models. In this research, we focus on historically-difficult problems in creating large-
scale (city size) scene models from sensor data, including rapid extraction and modeling of geometry models,
re-production of high-quality scene textures, and fusion and completion of the geometry and texture data to
produce photorealistic 3D scene models. We address the current problems and limitations of state of the
art techniques and present our solutions, including a fully automatic technique for extraction of polygonal
3D models from LiDAR data, and a flexible texture blending technique for generation of photorealistic
textures from multiple optical sensor resources. The result is a unified(multi-sensory),
comprehensive(structure and appearance) and immersive representation of large-scale areas of the real world.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Gredia Middleware Innovations, Dimitrios Tsoumakos (University of Cyprus, Cyprus), Tuesday, February 9th, 2010, 15:00-16:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Gredia Middleware Innovations
Speaker: Dimitrios Tsoumakos
Affiliation: University of Cyprus, Cyprus
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Tuesday, February 9th, 2010
Time: 15:00-16:30 EET
Host: Yannis Dimopoulos (yannis AT cs.ucy.ac.cy) and George Pallis (gpallis AT cs.ucy.ac.cy)
Abstract:
Grid technology has achieved significant advances in the past few
years with a plethora of prestigious organisations contributing to
middleware that opens the horizons for new exploitation opportunities.
However, this potential exploitation has not yet been seen to
materialise in emerging applications. The use of Grid technology is
still confined mainly within scientific applications, developed by
scientific organisations, being experts in Grid principles. GREDIA
(FP6 34363 - Grid enabled access to rich media content) addresses this
problem with the provision of a Grid application development platform.
In this talk I will describe the general goals of the GREDIA project
and specifically describe the design of the data/metadata layers of
its middleware component.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
PhD Defense: Cooperative Interactions in Converged Heterogeneous Communication Networks, Josephina Antoniou (University of Cyprus, Cyprus), Monday, January 18th, 2010, 9:30-10:30 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the PhD Defense entitled:
Cooperative Interactions in Converged Heterogeneous Communication Networks
Speaker: Josephina Antoniou
Affiliation: University of Cyprus, Cyprus
Category: PhD Defense
Location: Room 148, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Monday, January 18th, 2010
Time: 9:30-10:30 EET
Host: Andreas Pitsillides (Andreas.Pitsillides AT ucy.ac.cy)
Abstract:
Next Generation Communication Networks employ the idea of convergence, where heterogeneous access technologies may co-exist. Since in this new network model, a user (or a set of users) may be served by any (one or many) of the multiple, available access networks, the emergence of a new resource management mechanism is motivated to handle the selection of the most appropriate access network(s) for supporting a user request for a service (or a particular service demand). This new mechanism is known as Network Selection.
The triggering and execution of the Network Selection mechanism becomes a challenging task due to the heterogeneity of the entities involved, i.e. the user(s) and the access network(s). This heterogeneity results in different and often conflicting interests for these entities. Since cooperation between these entities, if achieved, is expected to be beneficial, we pose the following question: Can cooperation be motivated in interactive situations related to Network Selection, and if yes, is it beneficial for the interacting entities? In pursue of answering this question, this thesis isolates and studies three different interactive situations between user(s) and network(s) in a heterogeneous environment, which are related to Network Selection and proposes appropriate modes of behaviour that allow the interacting entities to achieve own satisfaction, despite their conflicting interests.
Short Bio:
Josephina Antoniou is a PhD Candidate at the Department of Computer Science, University of Cyprus.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
PhD Defense: Middleware-based Development of Context-aware Applications with Reusable Components, Nearchos Paspallis (University of Cyprus, Cyprus), Wednesday, September 30th, 2009, 10:00-11:00 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the PhD Defense entitled:
Middleware-based Development of Context-aware Applications with Reusable Components
Speaker: Nearchos Paspallis
Affiliation: University of Cyprus, Cyprus
Category: PhD Defense
Location: Room 148, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Wednesday, September 30th, 2009
Time: 10:00-11:00 EET
Host: George A. Papadopoulos (george AT cs.ucy.ac.cy)
Abstract:
Driven by the proliferation of mobile and pervasive computing, there is a growing demand for context-aware, self-adaptive applications. Such applications benefit users by dynamically adjusting their offered services to the highly dynamic context which characterizes mobile and pervasive computing environments. To achieve this kind of sophistication, however, such applications must be capable of sensing the context, and autonomously reacting upon their knowledge on it. However, enabling this kind of behavior inevitably results in a measurable increase to the complexity of the underlying software.
This presentation discusses the challenges in developing context-aware software and compiles an extensive list of requirements that need to be addressed. It then proposes a component-based development approach that facilitates reusability and eases the task of designing and implementing context-aware applications using separation-of-concerns. The development methodology is extended with a Model-driven development approach and is supported by a pluggable and modular middleware architecture which optimizes the resource consumption in run-time. The proposed approach is evaluated both quantitatively and qualitatively.
Short Bio:
Nearchos Paspallis is a PhD Candidate at the Department of Computer Science, University of Cyprus. He received an MSc in Computer Science from the University of California, Santa Barbara, and a BSc in Computer Engineering and Informatics from the University of Patras.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Broadcast Scheduling Algorithms for Ad-hoc TDMA Networks, Dr. Dimitrios D. Vergados (University of Pireaus, Greece), Tuesday, September 22nd, 2009, 10:30-12:00 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Broadcast Scheduling Algorithms for Ad-hoc TDMA Networks
Speaker: Dimitrios D. Vergados
Affiliation: University of Piraeus, Greece
Category: Course Lecture
Location: Room 005, Building XWD, New Campus (map)
Date: Tuesday, September 22nd, 2009
Time: 10:30-12:00 EET
Host: Vasos Vassiliou (vasosv AT cs.ucy.ac.cy)
Abstract:
Ad-hoc networks rely on multihop transmission among the nodes on the same channel. Possible simultaneous transmissions may cause collisions, whenever transmitting nodes have a common destination node in their interference range. To avoid these collisions while minimizing the frame length, the NP-complete Broadcast Scheduling Problem (BSP) should be approximated. This is usually done by interpreting the BSP into a corresponding Graph Coloring Problem. In this talk, I will presented a proposed algorithm that tries to approximate the BSP, using an interference vector. Additionally, the node ordering policies used for scheduling are evaluated in terms of frame length and execution time. Simulation results show that the proposed algorithm has smaller execution time than the ones using graph coloring, and decreasing degree ordering results to the best frame length.
Short Bio:
Dimitrios D. Vergados was born in Athens, Greece in 1973. He is a Lecturer in the Department of Informatics, University of Piraeus. He has held position as a Lecturer in the University of the Aegean, Department of Information and Communication Systems Engineering. He received his B.Sc. from the University of Ioannina and his Ph.D. from the National Technical University of Athens, Department of Electrical and Computer Engineering. His research interests are in the area of Communication Networks (Wireless Broadband Networks, Sensor Networks, Ad-hoc Networks, WLANs, IMS, Mesh Networks), Neural Networks, GRID Technologies, and Computer Vision. He has participated in several projects funded by EU and National Agencies and has several publications in journals, books and conference proceedings. He has served in technical program committees of several conferences. He is a guest editor and a reviewer in several journals.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Insect Visual Homing: Investigations of the Snapshot Model, Dr. Andrew Philippides (University of Sussex, UK), Monday, September 21th, 2009, 10:00-13:00 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Course Lecture entitled:
Insect Visual Homing: Investigations of the Snapshot Model
Speaker: Dr. Andrew Philippides
Affiliation: University of Sussex, UK
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Monday, September 21th, 2009
Time: 10:00-13:00 EET
Host: Christos Schizas (schizas AT cs.ucy.ac.cy)
Abstract:
Visual homing, the ability to get back to a nest or goal location using visual landmarks, is a vital capability for insects. Insects appear to achieve this behaviour through a process of image-matching in which the direction to nest or goal is recovered from the difference between the view from their current position and a view or 'snapshot' stored at the nest or goal position. Since this type of view-based homing was first proposed, simple, snapshot-type models have demonstrated successful homing performance over a range of environments and robotic platforms. In this talk, I will introduce the field of view-based homing and review the main snapshot-type models. I will then discuss three aspects of visual homing that I am currently working on: how the snapshot is learnt and used; what visual features make up the snapshot; and over what range a single snapshot is sufficient for homing.
I will first discuss recent work testing snapshot models in several natural environments. While it is known that insects use image matching to return home, the extent of the area within which insects can navigate in natural environments using a single snapshot has yet to be determined. This information is necessary before we can interpret data coming from the radar tracking of homing bees which some authors have used to conclude that a map-like representation is required for navigation over bees' natural foraging range. I will show that the information for homing can exist in natural environments over large-scales (100s of metres) and where in the world this information is coming from.
I will then discuss the results of this work in the light of both the natural visual ecology and natural behaviour of Australian Desert Ants as they navigate between nest and a feeder. Recent work by a colleague at Sussex has shown that the outline of objects against the skyline is sufficient for these ants to recover the direction home from the feeder. Here I will show that the skyline contains enough information for visual homing algorithms to function successfully. I will then discuss how the environment limits the range of a single snapshot, but that this range can be increased by considering the ant's required behaviour - route following - which leads to a simpler model of navigation.
I will conclude by discussing bumblebee learning flights and how this remarkable innate behaviour facilitates view-based homing. To enable them to locate their inconspicuous nest entrances using local visual landmarks, bees and wasps perform orientation or learning flights when they leave the nest to forage. This behaviour includes a number of stereotyped flight manoeuvres which appear to be structured to mediate the active acquisition of visual information. We have recorded and analysed bumblebee learning flights in multiple visual environments. Here I will present several flight strategies that bumblebees use to learn, and later find, the nest location during outward and return flights, respectively.
Short Bio:
Andrew Philippides is a Lecturer II within the Department of Informatics in the University of Sussex, where he is a member of the Sussex insect Navigation Group within the Centre for Computational Neuroscience and Robotics. He gained his doctorate in neuroscience at Sussex studying diffusible neuromodulators in real and artificial nervous systems and has been at Sussex ever since. While continuing his research into neuromodulation in networks, he also studies visual navigation in insects using a combination of behavioural experiments, mathematical and robotic modelling.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Course Lecture: Neuromodulation in Artificial Neural Networks, Dr. Andrew Philippides (University of Sussex, UK), Friday, September 18th, 2009, 15:00-18:00 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the Short Duration Course entitled:
Neuromodulation in Artificial Neural Networks
Speaker: Dr. Andrew Philippides
Affiliation: University of Sussex, UK
Category: Course Lecture
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus (map)
Date: Friday, September 18th, 2009
Time: 15:00-18:00 EET
Host: Christos Schizas (schizas AT cs.ucy.ac.cy)
Abstract:
The discovery of freely diffusing gaseous neurotransmitters, such as nitric oxide (NO), in biological nervous systems has radically altered the traditional connectionist picture of the brain. A type of artificial neural network (ANN) inspired by such gaseous signalling, the GasNet, has previously been shown to be more evolvable than traditional ANNs when used as an artificial nervous system in an evolutionary robotics setting. In this context evolvability means consistent speed to very good solutions - here, appropriate sensorimotor behaviour-generating systems. Inspired by recently discovered features of NO signalling in brains, several GasNet variants have been produced which further increase evolvability.
Subsequent work aiming to explain these results asked to what extent the coupling between the GasNet's two signalling mechanisms, one "chemical" and one "electrical", can explain the differences in network performance. The results of these investigations can be crystallised into three linked hypotheses on why the GasNets evolve faster:
1. The action of gas over multiple different timescales from the electrical activity introduces rich dynamics which can be exploited
2. The spatial embedding of the networks serves to (flexibly) couple two interacting signalling systems
3. The particular modulatory effects are key to evolvability
Interestingly, these three factors can be found in an oft-cited definition of neuromodulation:
"Any communication between neurons caused by the release of a chemical that is either not fast, or not point-to-point or not simply excitation or inhibition" (Katz, 1999)
In this talk, I will introduce the GasNet and its use as a controller for autonomous robots. I will present a summary of experiments which highlight the increased evolvability of the GasNet and which suggest the reasons lie in the factors highlighted above. I will then attempt to disentangle which of the abstracted elements of neuromodulation added into standard ANNs aid evolvability, by examining the hypotheses above in the light of various empirical studies, focusing on a comparison of variants of the basic GasNet formed by imposing constraints on spatial, temporal and modulatory properties.
Short Bio:
Andrew Philippides is a Lecturer II within the Department of Informatics in the University of Sussex, where he is a member of the Sussex insect Navigation Group within the Centre for Computational Neuroscience and Robotics. He gained his doctorate in neuroscience at Sussex studying diffusible neuromodulators in real and artificial nervous systems and has been at Sussex ever since. While continuing his research into neuromodulation in networks, he also studies visual navigation in insects using a combination of behavioural experiments, mathematical and robotic modelling.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
PhD Defense: Grid Computational Resource Performance Ranking and Auditing, Mr. George P. Tsouloupas (University of Cyprus), Monday, May 11th, 2009, 13:00 - 14:00 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the PhD defense entitled:
Grid Computational Resource Performance Ranking and Auditing
Speaker: Mr. George P. Tsouloupas
Affiliation: University of Cyprus, Cyprus
Category: PhD Defense
Location: Room 148, Building 12 Faculty of Pure and Applied Sciences, New Campus, University of Cyprus (map)
Date: Monday, May 11th, 2009
Time: 13:00 - 14:00 EET
Host: Marios Dikaiakos (mdd AT cs.ucy.ac.cy)
Abstract:
Over the recent years the area of Grid Computing has seen an astonishing growth. Grid infrastructures have become the platform of choice for large- scale eScience. The world's largest Grid infrastructure - EGEE - currently comprises 300 sites distributed around the world, petabytes of storage capacity and CPU's in excess of 80,000. The different computing resources in these heterogeneous infrastructures gather impressive and unprecedented computational potential, yet, in order to utilize them, users need mechanisms for selecting the right resources for the right job. Users and Virtual Organization administrators also need end-to-end mechanisms to evaluate the performance of resources and audit resources according to their advertised performance. This can be a complicated process, and when large infrastructures are involved, it becomes unmanageable and prohibitively tedious in the absence of specialized tools.
Performance ranking in a large, shared, heterogeneous and dynamic environment is a complex task because it needs to be done in an efficient and unobtrusive way. At the same time, it has to address many different types of application that come from several Virtual Organizations.
This thesis presents a methodology for putting correct, meaningful and contextualized performance information at the user's disposal, thus facilitating the ranking of computational resources based on customizable criteria. Contextualization is achieved by enriching the measurements with metadata about when, where, how and in many cases under what circumstances the measurement is obtained. The thesis proceeds to propose a userdriven approach for ranking resources by employing custom ranking functions.
GridBench is an extensible tool that has been designed and implemented in the context of this thesis and along the lines of this methodology. It allows for context-augmented performance evaluation using several types of benchmarks, ranging from synthetic microbenchmarks to real-world parallel applications. It demonstrates how the evaluation and ranking process, an otherwise complicated and tedious task, can be simplified. Grid- Bench features a user-friendly graphical interface that facilitates the invocation of tests and benchmark and the collection, archival and analysis of results. A primary component, SiteRank, enables the interactive user-driven creation of custom ranking functions and provides a ranking of resources according to a users' specification.
The methodology and tools are applied through several experiments to the largest production Grid infrastructure in existence today. Among the arguments of the thesis is that the use of evidence-based "measured" data, in contrast to the "quoted" data advertised in information services by resource owners, is imperative. The existing de facto approach for selecting resources according to performance is shown to be insufficient and unreliable.
Short Bio:
George P. Tsouloupas is a PhD Candidate at the Department of Computer Science, University of Cyprus.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Presentation: Building Robust Enterprise Data Centers, Mr. Michele Mazzucco (Newcastle University, UK), Monday, March 16th, 2009, 15:00 - 16:00 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the presentation entitled:
Building Robust Enterprise Data Centers
Speaker: Mr. Michele Mazzucco
Affiliation: University of Newcastle, UK
Category: Presentation
Location: Room 147, Building 12 Faculty of Pure and Applied Sciences, New Campus, University of Cyprus (map)
Date: Monday, March 16th, 2009
Time: 15:00 - 16:00 EET
Host: Marios Dikaiakos (mdd AT cs.ucy.ac.cy)
Abstract:
As IT systems are becoming more important everyday, one of the main concerns is that users may face major breakdowns and eventually incur major costs if computing systems do not meet the expected performance requirements. Even with the adoption of data centers as the hub of IT organizations and provider of business efficiencies the problems are not over because it is extremely difficult for service providers to meet the promised performance guarantees in spite of unpredictable user demand. One possible approach is the adoption of Service Level Agreements (SLAs), contracts that specify a level of performance that must be met and remedies in case of failure.
In this talk I will address some of the performance problems arising when IT companies sell the service of running 'jobs' subject to Quality of Service (QoS) constraints. QoS issues can be addressed from several perspectives, such as an engineering point of view (i.e., how to provide a service subject to performance constraints) or a semantic one (i.e., how to dynamically discover or select service with tight performance needs, or how to negotiate QoS requirements at run time). Here I will focus on the former one. First, I will define the problem in terms of an utility function to maximize, then I will present dynamic allocation and admission policies for enterprise data centers as well as an autonomic architecture for service provisioning.
Short Bio:
Michele Mazzucco received is BSc and MSc from University of Bologna (Italy) in 2003 and 2005 respectively. From 2006 to 2008 he worked as a Research Associate at the Newcastle University (UK) on a BT founded project. He is completing his PhD under the supervision of Prof. Isi Mitrani with a thesis focused on the design of adaptive service provisioning systems (part of the thesis is subject to an European Union patent application). Since March 2008 he is one of the committers at the Apache Software Foundation.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
PhD Defense: Active Ontology: Information Dynamicity Management in a Large Scale Distributed System, Mr. Wei Xing (University of Cyprus), Friday, March 13th, 2009, 13:00 - 14:00 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the PhD defense entitled:
Active Ontology: Information Dynamicity Management in a Large Scale Distributed System
Speaker: Mr. Wei Xing
Affiliation: University of Cyprus, Cyprus
Category: PhD Defense
Location: Room 148, Building 12 Faculty of Pure and Applied Sciences, New Campus, University of Cyprus (map)
Date: Friday, March 13th, 2009
Time: 13:00 - 14:00 EET
Host: Marios Dikaiakos (mdd AT cs.ucy.ac.cy)
Abstract:
Ontologies are a key technology for resolving the problem of information heterogeneity. A number of ontology based information integration systems has been developed that support information management tasks. However almost all of those systems rely on a number of assumptions about the nature of environment they are used in. One of these assumptions is that the domain is more or less static. In many realistic application scenarios for ontology based information systems, however, environments are highly dynamic. This is especially true to manage heterogeneous information in large scale distributed systems, such as Grids, cloud computing. In such environments, a number of issues are raised when applying an ontology based information integration approach for information management, because of changing information, changing ontology, and changing information sources.
This dissertation studies a key issue, semantic information dynamicity management in a large scale distributed environment. In our work we proposed an Active Ontology (ActOn) information model for representing dynamic information by strengthening ontology technology with a new dynamic management element. Based on the ActOn model, we developed a lifetime control and information source selection mechanisms to ensure the accurateness and consistence of the information that represented using ActOn model. Lifetime control is important for information quality. In fact, inaccurate information is an even bigger problem than missing information, because services or consumers relying on information will produce wrong actions or wrong results without warning. The selection of a suitable information source for information retrieving is particular important as the high alternative and redundancy of the available information sources in a large scale distributed environment. The idea behind ActOn model is simple: information is represented as instantiation of classes of ActOn domain ontology. In particular, it allows the value of dynamic part of information can be interpreted as an executable query; the execution of the query is controlled by its lift-time. The ActOn model comprises two kinds of ontologies, domain ontology and information source ontology, from which one can retrieve metadata to instantiate the model. A new ontology element DObject is particularly designed to link the domain ontology and the information source ontology, which in turn enable those ActOn instances be generated (or updated) dynamically in cope with the changes in a distributed environment. The life-time control mechanism is used to manage (update) dynamic information. The information source selection mechanism is used to select a suitable information source against the query execution from multiple information source candidates during the information life cycle management. To illustrate the usefulness of our ActOn model, a design and development of an ActOnbased information service for EGEE Grid is presented. The main difference with respect to other Grid information services is that it incorporate two ActOn specific modules that are not commonly found in others: a semantic information cache with lifetime management, which provides fast access to information that has been already integrated and materialized and which is still valid, and an information source selector, which is used during the generation of the execution plan for retrieving information from the information sources and allows system to adapt to changing conditions of the EGEE Grid infrastructure and to add new information sources easily.
Another important aspect of our research is the study of information quality in a large scale distributed environment. We proposed a fair systematic approach to measure information quality of different information services deployed in a large scale distributed environment. Our proposed evolution framework mainly tests three key metrics of information: information completeness, consistency, and accessibility. We conducted experiments to compare and analysis two EGEE deployed information services (BDII and RGMA) and the ActOn information service on EGEE production testbed.
Short Bio:
Wei Xing is a PhD Candidate at the Department of Computer Science, University of Cyprus.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Demonstration: Digital Libraries and Tools for Organizing Bibliography, Mr. Louis Prokopiou (University of Cyprus, Cyprus), Friday, March 6th, 2009, 15:00 - 16:00 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the demonstration entitled:
Digital Libraries and Tools for Organizing Bibliography
Speaker: Mr. Louis Prokopiou
Affiliation: Library, University of Cyprus
Category: Demonstration
Location: Room 021, Building 12 Faculty of Pure and Applied Sciences, New Campus, University of Cyprus (map)
Date: Friday, March 6th, 2009
Time: 15:00 - 16:00 EET
Host: Marios Dikaiakos (mdd AT cs.ucy.ac.cy)
Abstract:
Στην παρουσίαση αυτή θα γίνει αναφορά στον τρόπο αναζήτησης σε βάσεις δεδομένων βιβλιογραφικής φύσεως (Scopus, WebofScience, Googlescholar κ.α.) με σκοπό τον εντοπισμό ηλεκτρονικού υλικού (άρθρων, βιβλίων, τεχνικών εκθέσεων) και στη συνέχεια διαχείρισής του με εργαλεία διαχείρισης βιβλιογραφίας και συγκεκριμένα με το RefWorks. Το RefWorks είναι ένα εργαλείο οργάνωσης και διαχείρισης βιβλιογραφίας και βιβλιογραφικών αναφορών. Παρέχει την δυνατότητα δημιουργίας προσωπικής βάσης δεδομένων, εισάγοντας βιβλιογραφικές αναφορές απευθείας από δικτυακές βάσεις βιβλιογραφικών δεδομένων ή χειρωνακτικά, από κατάλληλα ηλεκτρονικά αρχεία κειμένου. Επίσης παρέχει την δυνατότητα μορφοποίησης των αναφορών αυτών (MLA, APA, Chicago Manual of Style, Turabian, κ.α.) και χρήσης τους για την δημιουργία βιβλιογραφιών σε επιστημονικά συγγράμματα, άρθρα, εργασίες κλπ. Στην παρουσίαση θα γίνει αναλυτική επίδειξη των λειτουργιών του εργαλείου όπως εισαγωγή και εξαγωγή αναφορών στην εσωτερική βάση του Refworks, οργάνωση και διαχείριση αναφορών, ετοιμασία και συγγραφή βιβλιογραφίας για εργασίες και δημιουργία παραπομπών (citation) σε κείμενα με αυτόματη ενημέρωση της τελικής βιβλιογραφικής λίστας.
Short Bio:
Ο Λούης Προκοπίου είναι υπεύθυνος του Γραφείου Διαχείρισης Έργων της ΒΠΚ και απόφοιτος του τμήματος Επιστημών της Αγωγής του Πανεπιστημίου Κύπρου. Για περισσότερες πληροφορίες επικοινωνήστε με το Λούη Προκοπίου στο 22892016 ή στην ηλεκτρονική διεύθυνση Prokopiou.louis@ucy.ac.cy
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
PhD Defense: The TFlux Parallel Processing Platform, Mr. Kyriakos Stavrou (University of Cyprus), Friday, January 24th, 2009, 11:00 - 12:00 EET.
The Department of Computer Science at the University of Cyprus cordially invites you to the PhD defense entitled:
The TFlux Parallel Processing Platform
Speaker: Mr. Kyriakos Stavrou
Affiliation: University of Cyprus, Cyprus
Category: PhD Defense
Location: Room 148, Building 12 Faculty of Pure and Applied Sciences, New Campus, University of Cyprus (map)
Date: Friday, January 24th, 2009
Time: 11:00 - 12:00 EET
Host: Pedro Trancoso (pedro AT cs.ucy.ac.cy)
Abstract:
This work presents the TFlux (Thread Flux) Parallel Processing Platform, a complete system that offers an efficient dataflow-like thread-based model of execution, the Data-Driven Multithreading (DDM), to its users using commodity components, i.e. unmodified Operating System, unmodified compiler and unmodified ISA hardware making it applicable to off-the-shelf systems. TFlux provides a complete solution from the programming toolchain to the hardware implementation. The abstraction layer TFlux exports to its users hides all the details of the underlying machine allowing different hardware configurations to support its model of execution transparently to the programmer.
The user of TFlux can develop applications using a set of simple but powerful compiler directives. Then the TFlux-C-Preprocessor coverts this code to an ANSI C program that includes the Runtime Support for TFlux and all calls to the system’s scheduler. This code can be compiled with a commodity C compiler resulting in a binary that is executable by any commodity Operating Systems on any commodity CPU processors. The layered design of TFlux has been tested on different Unix-based multiprocessor systems. Moreover, this design enabled the porting of TFlux to different machines with minimum effort.
In this work, two TFlux implementations are presented: TFluxHard and TFluxSoft. For TFluxHard the thread Scheduler is implemented as a hardware unit whereas for TFluxSoft, the Scheduler’s functionality is provided at the software level. As such, TFluxHard is applicable to systems that offer the ability to augment the machine with a small hardware module while TFluxSoft is directly applicable to any existing off-the-shelf systems. To evaluate the TFlux implementations, a benchmark suite based on existing and synthetic applications was developed. The applications in this suite were carefully chosen in order to have different characteristics both in terms of their dynamic behavior and complexity of their dataflow graph. Although for most applications the performance of the two implementations is close, TFluxHard shows an advantage over TFluxSoft arising from offloading the Scheduler’s functionality to the hardware module.
In addition, the experimental results also show that TFlux is able to exploit better the parallelism for applications with complex dependency graphs, compared with traditional parallel programming model approaches. Overall, TFlux proves to be a platform that allows applications to efficiently exploit the available parallelism. This is achieved by supporting dataflow-like thread scheduling in commodity multicore/multiprocessor systems.
Short Bio:
Kyriakos Stavrou is a PhD Candidate at the Department of Computer Science, University of Cyprus.
| Other Presentations Web: http://www.cs.ucy.ac.cy/colloquium/presentations.php |
| Colloquiums Web: http://www.cs.ucy.ac.cy/colloquium/ |
Copyright University of Cyprus, Credits: Demetris Zeinalipour