Christos Bouras
Short CV: Christos Bouras is Professor in the University of Patras, Department of Computer Engineering and Informatics. Also he is a scientific advisor of Research Unit 6 in Computer Technology Institute and Press – Diophantus, Patras, Greece. His research interests include Analysis of Performance of Networking and Computer Systems, Computer Networks and Protocols, Mobile and Wireless Communications, Telematics and New Services, QoS and Pricing for Networks and Services, e-learning, Networked Virtual Environments and WWW Issues. He has extended professional experience in Design and Analysis of Networks, Protocols, Telematics and New Services. He has published more than 450 papers in various well-known refereed books, conferences and journals. He is a co-author of 9 books in Greek and editor of 2 in English. He has been member of editorial board for international journals and PC member and referee in various international journals and conferences. He has participated in R&D projects.
Conferences
Bouras, Christos; Spirakis, Paul; Lampsas, P; Antoniou, I
Enabling Distance Education over the World Wide Web Conference
World Conference of the WWW, Internet and Intranet- WebNet 97,Torodo,Canada, pp. 1, 1997.
Abstract | Links | BibTeX | Tags:
@conference{2842,
title = {Enabling Distance Education over the World Wide Web},
author = {Christos Bouras and Paul Spirakis and P Lampsas and I Antoniou},
url = {https://telematics.upatras.gr/9195524/},
year = {1997},
date = {1997-10-01},
urldate = {1997-10-01},
booktitle = {World Conference of the WWW, Internet and Intranet- WebNet 97,Torodo,Canada, pp. 1},
abstract = {The recent advancements in the field of the information and communication technology resulted in a revolution comparable to the industrial revolution. The basis of this revolution is the information and the value it has as the pure expression of human knowledge. The technological advancements offer us the ability to process, store, retrieve and transmit information in multiple formats (text, sound, image, video) independently of time, volume and distance. In this paper we present the technology that is required and an architecture for the realization of distance education over the World Wide Web. We also address some basic aspects of the users’ needs that every software tool for distance education should meet.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The recent advancements in the field of the information and communication technology resulted in a revolution comparable to the industrial revolution. The basis of this revolution is the information and the value it has as the pure expression of human knowledge. The technological advancements offer us the ability to process, store, retrieve and transmit information in multiple formats (text, sound, image, video) independently of time, volume and distance. In this paper we present the technology that is required and an architecture for the realization of distance education over the World Wide Web. We also address some basic aspects of the users’ needs that every software tool for distance education should meet.
Bouras, Christos; Konidaris, Agis; Sevasti, Afroditi; Kontogiannis, S; Fotakis, D; Katanou, A; Stephanou, E
Major Principles on the Design of an Educational Network Conference
Open Classroom II Conference, Crete, Greece, pp. 359-366, 1997.
Abstract | Links | BibTeX | Tags:
@conference{2839,
title = {Major Principles on the Design of an Educational Network},
author = {Christos Bouras and Agis Konidaris and Afroditi Sevasti and S Kontogiannis and D Fotakis and A Katanou and E Stephanou},
url = {https://telematics.upatras.gr/4819276/},
year = {1997},
date = {1997-09-01},
urldate = {1997-09-01},
booktitle = {Open Classroom II Conference, Crete, Greece, pp. 359-366},
pages = {359 - 366},
abstract = {The modern communication networks, apart from the specialized applications that they offer depending on the nature of their target groups, they support a set of general purpose elementary network services, that provide some essential communication facilities to the end users. Regarding an educational network, these facilities include collaboration, navigation into the information resources, as well as interpersonal communication, to the members of the Education Society. In the sequel the major principles on providing these elementary network services are presented. On-lline/off-line contact over an alternative means of communication among the members of the trans-European Education Society could be an adequate reason for the deployment of an educational communication network. This category of services will offer the members of the Education Society the ability of exchanging opinions on educational and social matters, as well as interpersonal messages, and collaborating. These facilities should be provided by already existing network services, enhanced where necessary by supporting multimedia information exchange (mostly off-line). In the latter case external media players of attachment viewers may be used for the presentation of the multiple media of information.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The modern communication networks, apart from the specialized applications that they offer depending on the nature of their target groups, they support a set of general purpose elementary network services, that provide some essential communication facilities to the end users. Regarding an educational network, these facilities include collaboration, navigation into the information resources, as well as interpersonal communication, to the members of the Education Society. In the sequel the major principles on providing these elementary network services are presented. On-lline/off-line contact over an alternative means of communication among the members of the trans-European Education Society could be an adequate reason for the deployment of an educational communication network. This category of services will offer the members of the Education Society the ability of exchanging opinions on educational and social matters, as well as interpersonal messages, and collaborating. These facilities should be provided by already existing network services, enhanced where necessary by supporting multimedia information exchange (mostly off-line). In the latter case external media players of attachment viewers may be used for the presentation of the multiple media of information.
Bouras, Christos; Spirakis, Paul; Triantafillou, Vasilis; Garofalakis, J
A General Performance Model for Multistage Interconnection Networks Conference
Euro-Par ’97, Passau, Germany, pp. 993-1000, 1997.
Abstract | Links | BibTeX | Tags:
@conference{2845,
title = {A General Performance Model for Multistage Interconnection Networks},
author = {Christos Bouras and Paul Spirakis and Vasilis Triantafillou and J Garofalakis},
url = {https://telematics.upatras.gr/2305355/},
year = {1997},
date = {1997-08-01},
urldate = {1997-08-01},
booktitle = {Euro-Par ’97, Passau, Germany, pp. 993-1000},
pages = {993 - 1000},
abstract = {Multistage Interconnection Networks (MINs) with crossbar switches are used to interconnect processors and memory modules in parallel multiprocessor systems. In this paper we analyze the general case of MINs, made of kk switches with nite, in nite or zero length buffers (unbuffered). The exact solution of the steady state distribution of the rst stage is derived for all cases. We use this to get an approximation for the steady state distributions in the second stage and beyond. In the case of unbu ered switches we reach the known exact solution for all the stages of the MIN. Our results are validated by extensive simulations. Keywords: analytical models, queueing theory models, evaluation.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Multistage Interconnection Networks (MINs) with crossbar switches are used to interconnect processors and memory modules in parallel multiprocessor systems. In this paper we analyze the general case of MINs, made of kk switches with nite, in nite or zero length buffers (unbuffered). The exact solution of the steady state distribution of the rst stage is derived for all cases. We use this to get an approximation for the steady state distributions in the second stage and beyond. In the case of unbu ered switches we reach the known exact solution for all the stages of the MIN. Our results are validated by extensive simulations. Keywords: analytical models, queueing theory models, evaluation.
Bouras, Christos; Spirakis, Paul; Lampsas, P; Tsakarissianos, G; Garofalakis, J; Antonis, K; Kastis, N; Kontogiannis, S
Conclusions on the Analysis of User Requirements concerning the use of ICT in the Didactic Process Conference
ED-MEDIA/ED-TELECOM 97, Calgary, Canada, pp. 13-18, 1997.
Abstract | Links | BibTeX | Tags:
@conference{2837,
title = {Conclusions on the Analysis of User Requirements concerning the use of ICT in the Didactic Process},
author = {Christos Bouras and Paul Spirakis and P Lampsas and G Tsakarissianos and J Garofalakis and K Antonis and N Kastis and S Kontogiannis},
url = {https://telematics.upatras.gr/4993265/},
year = {1997},
date = {1997-06-01},
urldate = {1997-06-01},
booktitle = {ED-MEDIA/ED-TELECOM 97, Calgary, Canada, pp. 13-18},
pages = {13 - 18},
abstract = {The co-operation of the Information and Communications Technologies (ICT) and the Educational Society, is deemed necessary for the adaptation and tuning of the
didactic process in terms of pedagogical methodologies, school infrastructure, human resources utilisation and organisational restructuring. The use of ICT in the classroom
should be viewed as a highly influencing tool that will support the educators’ effort for interaction with their students, rather than as a technical exercise. The initial phases of the TRENDS project, which are described in this paper, resulted in a widely accepted common methodology, that complies with the international standards for determining the User Requirements in the Secondary Education. The major results emerged from this survey are presented here, as well as some common axes that deal with the application of ICT in the didactic process.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The co-operation of the Information and Communications Technologies (ICT) and the Educational Society, is deemed necessary for the adaptation and tuning of the
didactic process in terms of pedagogical methodologies, school infrastructure, human resources utilisation and organisational restructuring. The use of ICT in the classroom
should be viewed as a highly influencing tool that will support the educators’ effort for interaction with their students, rather than as a technical exercise. The initial phases of the TRENDS project, which are described in this paper, resulted in a widely accepted common methodology, that complies with the international standards for determining the User Requirements in the Secondary Education. The major results emerged from this survey are presented here, as well as some common axes that deal with the application of ICT in the didactic process.
didactic process in terms of pedagogical methodologies, school infrastructure, human resources utilisation and organisational restructuring. The use of ICT in the classroom
should be viewed as a highly influencing tool that will support the educators’ effort for interaction with their students, rather than as a technical exercise. The initial phases of the TRENDS project, which are described in this paper, resulted in a widely accepted common methodology, that complies with the international standards for determining the User Requirements in the Secondary Education. The major results emerged from this survey are presented here, as well as some common axes that deal with the application of ICT in the didactic process.
Bouras, Christos; Spirakis, Paul; Lampsas, P
Superhighways for Open and Distance Learning Conference
1997 EDEN Conference, Budapest, Hungary, pp. 32-36, 1997.
Abstract | Links | BibTeX | Tags:
@conference{2843,
title = {Superhighways for Open and Distance Learning},
author = {Christos Bouras and Paul Spirakis and P Lampsas},
url = {https://telematics.upatras.gr/7093481/},
year = {1997},
date = {1997-06-01},
urldate = {1997-06-01},
booktitle = {1997 EDEN Conference, Budapest, Hungary, pp. 32-36},
pages = {32 - 36},
abstract = {An educational information network, is a multimedia network with a centralized architecture for the provision of educational services. The educational services comprise basic network applications (such as multimedia e-mail, fora for debates on educational subjects, access to already existing information), video distribution of multimedia lessons and a custom developed teletraining tool for the conduction of lessons over a broadband networking infrastructure. The suitability of the widely available broadband networking technologies (ATM, ISDN), as opposed to the alternative of using already existing networking infrastructure (Internet, CATV), for the implementation of educational networks for the realization of an Open and Distance Learning Environment will be examined. More specifically the types of educational services that can be best hosted by each technology and the costs as opposed to the maturity for the deployment of each networking technology will be cited. Finally, a proposal for an implementation scheme of an educational information network, concerning the appropriate (and cost effective) networking infrastructure that can best accommodate the aforementioned educational services will be elaborated.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
An educational information network, is a multimedia network with a centralized architecture for the provision of educational services. The educational services comprise basic network applications (such as multimedia e-mail, fora for debates on educational subjects, access to already existing information), video distribution of multimedia lessons and a custom developed teletraining tool for the conduction of lessons over a broadband networking infrastructure. The suitability of the widely available broadband networking technologies (ATM, ISDN), as opposed to the alternative of using already existing networking infrastructure (Internet, CATV), for the implementation of educational networks for the realization of an Open and Distance Learning Environment will be examined. More specifically the types of educational services that can be best hosted by each technology and the costs as opposed to the maturity for the deployment of each networking technology will be cited. Finally, a proposal for an implementation scheme of an educational information network, concerning the appropriate (and cost effective) networking infrastructure that can best accommodate the aforementioned educational services will be elaborated.
Bouras, Christos; Kapoulas, Vaggelis; Spirakis, Paul; Tatakis, A
An HTML like language supporting time-depended transmission of hypermedia Conference
The Eighth International ACM Hypertext Conference-Hypertext 97, Southampton, UK, pp. 1-21, 1997.
@conference{2844,
title = {An HTML like language supporting time-depended transmission of hypermedia},
author = {Christos Bouras and Vaggelis Kapoulas and Paul Spirakis and A Tatakis},
url = {https://telematics.upatras.gr/6214354/},
year = {1997},
date = {1997-04-01},
urldate = {1997-04-01},
booktitle = {The Eighth International ACM Hypertext Conference-Hypertext 97, Southampton, UK, pp. 1-21},
pages = {1 - 21},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Bouras, Christos; Spirakis, Paul; Moiras, D; Ouzounis, V; Antoniou, I
HY-MOST: HYpermedia MOdel for Synchronised presenTations Conference
3rd Workshop on Open Hypermedia Systems, Southampton, UK, pp. 18-23, 1997.
Abstract | Links | BibTeX | Tags:
@conference{2846,
title = {HY-MOST: HYpermedia MOdel for Synchronised presenTations},
author = {Christos Bouras and Paul Spirakis and D Moiras and V Ouzounis and I Antoniou},
url = {https://telematics.upatras.gr/1281572/},
year = {1997},
date = {1997-04-01},
urldate = {1997-04-01},
booktitle = {3rd Workshop on Open Hypermedia Systems, Southampton, UK, pp. 18-23},
pages = {18 - 23},
abstract = {A brief abstract. In this paper we present a new model for hypermedia presentations. This model is based on an HTML-like language which provides the necessary modules
for the intermedia synchronisation of the inline media that comprise the hypermedia document. The model also enables a distributed approach in the storage of the hypermedia documents. Additionally, it is capable of incorporating the necessary protocols needed for the real-time delivery of continuous media such as audio and video.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
A brief abstract. In this paper we present a new model for hypermedia presentations. This model is based on an HTML-like language which provides the necessary modules
for the intermedia synchronisation of the inline media that comprise the hypermedia document. The model also enables a distributed approach in the storage of the hypermedia documents. Additionally, it is capable of incorporating the necessary protocols needed for the real-time delivery of continuous media such as audio and video.
for the intermedia synchronisation of the inline media that comprise the hypermedia document. The model also enables a distributed approach in the storage of the hypermedia documents. Additionally, it is capable of incorporating the necessary protocols needed for the real-time delivery of continuous media such as audio and video.
Bouras, Christos; Spirakis, Paul; Lampsas, P
In-Service Training through ODL Environments:From User Needs To Functional Specifications Conference
8th International Conference Society for Information Technology and Teacher Education-SITE 97, Orlando, USA, pp. 519-522, 1997.
@conference{2838,
title = {In-Service Training through ODL Environments:From User Needs To Functional Specifications},
author = {Christos Bouras and Paul Spirakis and P Lampsas},
url = {https://telematics.upatras.gr/5744275/},
year = {1997},
date = {1997-04-01},
urldate = {1997-04-01},
booktitle = {8th International Conference Society for Information Technology and Teacher Education-SITE 97, Orlando, USA, pp. 519-522},
pages = {519 - 522},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Bouras, Christos; Kapoulas, Vaggelis; Spirakis, Paul; Moiras, D; Ouzounis, V; Antoniou, I; Karageorgopoylos, D
Hermes Service: Distributed Hypermedia Educational Services on Demand Conference
ED-MEDIA/ED-TELECOM 97, Calgary, Canada, pp. 19-24, 1997.
Abstract | Links | BibTeX | Tags:
@conference{2840,
title = {Hermes Service: Distributed Hypermedia Educational Services on Demand},
author = {Christos Bouras and Vaggelis Kapoulas and Paul Spirakis and D Moiras and V Ouzounis and I Antoniou and D Karageorgopoylos},
url = {https://telematics.upatras.gr/6594271/},
year = {1997},
date = {1997-01-01},
urldate = {1997-01-01},
booktitle = {ED-MEDIA/ED-TELECOM 97, Calgary, Canada, pp. 19-24},
pages = {19 - 24},
abstract = {In this paper we present a distributed HypERMEdia SERVICE (HERMES SERVICE) which supports integrated capabilities for distance education and learning purposes. Hermes service consists of hermes servers and hermes browsers. The users are connected with the service using hermes browsers and retrieve hypermedia lessons organised in thematical units. The lessons are stored in various distributed Hermes servers which retrieve the requested lesson and transmit it to the corresponding browser on on-demand basis. The requested lesson is presented to the user according to a well defined presentation scenario. The media objects are rendered in a synchronized manner according to the spatio-temporal relationships existing among them. Finally, special monitoring mechanism controls the state of the network and adjusts the presentation process so as to improve presentation quality.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
In this paper we present a distributed HypERMEdia SERVICE (HERMES SERVICE) which supports integrated capabilities for distance education and learning purposes. Hermes service consists of hermes servers and hermes browsers. The users are connected with the service using hermes browsers and retrieve hypermedia lessons organised in thematical units. The lessons are stored in various distributed Hermes servers which retrieve the requested lesson and transmit it to the corresponding browser on on-demand basis. The requested lesson is presented to the user according to a well defined presentation scenario. The media objects are rendered in a synchronized manner according to the spatio-temporal relationships existing among them. Finally, special monitoring mechanism controls the state of the network and adjusts the presentation process so as to improve presentation quality.
Bouras, Christos; Kapoulas, Vaggelis; Spirakis, Paul; Moiras, D; Ouzounis, V; Tatakis, A
On-Demand Hypermedia/Multimedia Service over Broadband Networks Conference
5th IEEE International Symposium On High Performance Distributed Computing-HPDC-5, Syracuse, New York, USA, pp. 224-231, 1996.
Abstract | Links | BibTeX | Tags:
@conference{2848,
title = {On-Demand Hypermedia/Multimedia Service over Broadband Networks},
author = {Christos Bouras and Vaggelis Kapoulas and Paul Spirakis and D Moiras and V Ouzounis and A Tatakis},
url = {https://telematics.upatras.gr/8142358/},
year = {1996},
date = {1996-08-01},
urldate = {1996-08-01},
booktitle = {5th IEEE International Symposium On High Performance Distributed Computing-HPDC-5, Syracuse, New York, USA, pp. 224-231},
pages = {224 - 231},
abstract = {In this paper we present a uni ed approach for delivering hypermedia/multimedia objects over broadband networks. Documents are stored in various multimedia servers, while the inline data may reside in their own media servers, attached to the multimedia servers. The described service consists of several multimedia servers and a set of functions that intend to present to the end user interactive information in real-time. Users interact with the service requesting multimedia documents on demand. Various media streams are transmitted over di erent parallel connections according to their transmission requirements. The hypermedia documents are structured using a hypermedia markup language that keeps information of the spatiotemporal relationships among document’s media components. In order to deal with the variant network behavior, buffering manipulation mechanisms and grading of the transmitted media quality techniques are proposed to smooth presentation and synchronization anomalies.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
In this paper we present a uni ed approach for delivering hypermedia/multimedia objects over broadband networks. Documents are stored in various multimedia servers, while the inline data may reside in their own media servers, attached to the multimedia servers. The described service consists of several multimedia servers and a set of functions that intend to present to the end user interactive information in real-time. Users interact with the service requesting multimedia documents on demand. Various media streams are transmitted over di erent parallel connections according to their transmission requirements. The hypermedia documents are structured using a hypermedia markup language that keeps information of the spatiotemporal relationships among document’s media components. In order to deal with the variant network behavior, buffering manipulation mechanisms and grading of the transmitted media quality techniques are proposed to smooth presentation and synchronization anomalies.
Bouras, Christos; Kapoulas, Vaggelis; Spirakis, Paul; Tsakarissianos, G; Kastis, N
TRENDS: Training Educators through Networks and Distributed Systems Conference
EDEN Conference 1996, Futuroscope Poitiers, France, pp. 195-199, 1996.
Abstract | Links | BibTeX | Tags:
@conference{2851,
title = {TRENDS: Training Educators through Networks and Distributed Systems},
author = {Christos Bouras and Vaggelis Kapoulas and Paul Spirakis and G Tsakarissianos and N Kastis},
url = {https://telematics.upatras.gr/7831439/},
year = {1996},
date = {1996-07-01},
urldate = {1996-07-01},
booktitle = {EDEN Conference 1996, Futuroscope Poitiers, France, pp. 195-199},
pages = {195 - 199},
abstract = {The TRENDS project aims at the in-service, distance training of 2,400 school teachers in Secondary Education, and the use of Information Technology and Telematics in the learning process, by six countries (Greece, Italy, Spain, Portugal, France, and United Kingdom). The training process will be implemented by flexible and distance learning methods, through the development and use of an in-service school-based training system, which will be based on multimedia telematics and existing mature network technologies, and the establishment and operation of a European Teacher’s Training Network, consisted of six interconnected National Sites (Training Centre, schools and teachers per country). Each Training Centre in the Network will act as service provider to the schools and the teachers. The major aspect of the project is to provide the educator and their trainers, with various services including : e-mail contact with other educators and trainers, access to multimedia information, forums for the discussion and debate on educational projects, access to curriculum-related information for the educators, and multimedia teletraining for the conduction of lessons over the network. Due
to the nature of the planned services and applications, the network infrastructure that will be used for the realization of the TRENDS, must offer high speed, multicasting, trans-European interoperability and certified quality of services.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The TRENDS project aims at the in-service, distance training of 2,400 school teachers in Secondary Education, and the use of Information Technology and Telematics in the learning process, by six countries (Greece, Italy, Spain, Portugal, France, and United Kingdom). The training process will be implemented by flexible and distance learning methods, through the development and use of an in-service school-based training system, which will be based on multimedia telematics and existing mature network technologies, and the establishment and operation of a European Teacher’s Training Network, consisted of six interconnected National Sites (Training Centre, schools and teachers per country). Each Training Centre in the Network will act as service provider to the schools and the teachers. The major aspect of the project is to provide the educator and their trainers, with various services including : e-mail contact with other educators and trainers, access to multimedia information, forums for the discussion and debate on educational projects, access to curriculum-related information for the educators, and multimedia teletraining for the conduction of lessons over the network. Due
to the nature of the planned services and applications, the network infrastructure that will be used for the realization of the TRENDS, must offer high speed, multicasting, trans-European interoperability and certified quality of services.
to the nature of the planned services and applications, the network infrastructure that will be used for the realization of the TRENDS, must offer high speed, multicasting, trans-European interoperability and certified quality of services.
Bouras, Christos; Kapoulas, Vaggelis; Spirakis, Paul; Lampsas, P; Tatakis, A; Kontogiannis, S; Fotakis, D; Kyriakou, K
An Interactive Cooperative Teleworking Environment-Tηλεµάθεια * Conference
ED-TELECOM 96, Boston, USA, pp. 37-42, 1996.
Abstract | Links | BibTeX | Tags:
@conference{2852,
title = {An Interactive Cooperative Teleworking Environment-Tηλεµάθεια *},
author = {Christos Bouras and Vaggelis Kapoulas and Paul Spirakis and P Lampsas and A Tatakis and S Kontogiannis and D Fotakis and K Kyriakou},
url = {https://telematics.upatras.gr/1055303/},
year = {1996},
date = {1996-06-01},
urldate = {1996-06-01},
booktitle = {ED-TELECOM 96, Boston, USA, pp. 37-42},
pages = {37 - 42},
abstract = {In this paper we present the design and the implementation of an interactive environment for cooperative teleworking. Telemathea offers tools that support the communication and the teleworking between tutor and trainee, who may reside in remote geographical regions. This environment offers audio communication over the network as well as support for joint editing of text documents and still images. It supports different audio coding techniques so as to adjust to the available bandwidth, and makes use of the RTP protocol in order to facilitate the exchange of audio and, in the future, video packets.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
In this paper we present the design and the implementation of an interactive environment for cooperative teleworking. Telemathea offers tools that support the communication and the teleworking between tutor and trainee, who may reside in remote geographical regions. This environment offers audio communication over the network as well as support for joint editing of text documents and still images. It supports different audio coding techniques so as to adjust to the available bandwidth, and makes use of the RTP protocol in order to facilitate the exchange of audio and, in the future, video packets.
Bouras, Christos; Kapoulas, Vaggelis; Spirakis, Paul; Tatakis, A; Fotakis, D; Balaouras, P; Chadelis, L; Palikarakis, N; Sandalatzopoulos, R
FINE:Implementation of a Distributed Telematics Environment for Clinical Engineers Conference
1996 Concurrent Engineering Europe, Cambridge, UK, pp. 56-60, 1996.
@conference{2850,
title = {FINE:Implementation of a Distributed Telematics Environment for Clinical Engineers},
author = {Christos Bouras and Vaggelis Kapoulas and Paul Spirakis and A Tatakis and D Fotakis and P Balaouras and L Chadelis and N Palikarakis and R Sandalatzopoulos},
url = {https://telematics.upatras.gr/8533438/},
year = {1996},
date = {1996-04-01},
urldate = {1996-04-01},
booktitle = {1996 Concurrent Engineering Europe, Cambridge, UK, pp. 56-60},
pages = {56 - 60},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Bouras, Christos; Kapoulas, Vaggelis; Spirakis, Paul; Pantziou, G
Randomized adaptive video on demand Conference
15th ACM-PODC, Philadelphia PA, USA, pp. 179, 1996.
@conference{2849,
title = {Randomized adaptive video on demand},
author = {Christos Bouras and Vaggelis Kapoulas and Paul Spirakis and G Pantziou},
url = {https://telematics.upatras.gr/1232344/},
year = {1996},
date = {1996-01-01},
urldate = {1996-01-01},
booktitle = {15th ACM-PODC, Philadelphia PA, USA, pp. 179},
pages = {179},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Bouras, Christos; Kapoulas, Vaggelis; Spirakis, Paul; Lampsas, P; Tatakis, A; Kontogiannis, S; Fotakis, D
Multilingual Implementations of OSI Applications Conference
10th International Symposium on Computers and Information Sciences-ISCIS X, Izmir, Turkey, pp. 367-374, 1995.
Abstract | Links | BibTeX | Tags:
@conference{2854,
title = {Multilingual Implementations of OSI Applications},
author = {Christos Bouras and Vaggelis Kapoulas and Paul Spirakis and P Lampsas and A Tatakis and S Kontogiannis and D Fotakis},
url = {https://telematics.upatras.gr/4960440/},
year = {1995},
date = {1995-10-01},
urldate = {1995-10-01},
booktitle = {10th International Symposium on Computers and Information Sciences-ISCIS X, Izmir, Turkey, pp. 367-374},
pages = {367 - 374},
abstract = {In this work the problem of supporting multilingual environments over OSI applications is addressed. Initially a solution based on the idea of using multilingual structures and transcription techniques is presented. Another solution based on the major principles of the former follows, which exploits the coding of all of character sets uniformally.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
In this work the problem of supporting multilingual environments over OSI applications is addressed. Initially a solution based on the idea of using multilingual structures and transcription techniques is presented. Another solution based on the major principles of the former follows, which exploits the coding of all of character sets uniformally.
Bouras, Christos; Kapoulas, Vaggelis; Spirakis, Paul; Lampsas, P; Tatakis, A; Fotakis, D; Papoutsopoulos, G
HIPPOCRATES: A multimedia tool for distance education Conference
ED-MEDIA 95, Gratz, Austria, pp. 103-108, 1995.
Abstract | Links | BibTeX | Tags:
@conference{2853,
title = {HIPPOCRATES: A multimedia tool for distance education},
author = {Christos Bouras and Vaggelis Kapoulas and Paul Spirakis and P Lampsas and A Tatakis and D Fotakis and G Papoutsopoulos},
url = {https://telematics.upatras.gr/2777305/},
year = {1995},
date = {1995-06-01},
urldate = {1995-06-01},
booktitle = {ED-MEDIA 95, Gratz, Austria, pp. 103-108},
pages = {103 - 108},
abstract = {In this paper we present a software tool for the realisation of the distance education service, that is the conduction of classes through the use of computers. The classes
are directed towards personnel in various areas and aim at the retraining and update of the personnel in subjects of special interest in their line of work. The conduction of
classes takes place, from and towards, remote regions with the aid of a computer network. Hippocrates is a flexible and easy-to-use application, which permits students, who sit in front of remotely situated workstations, to attend classes or seminars given by a teacher or expert, who can also be located in some remote geographical area. Hippocrates can be thought of as a distributed transparency projector. The teacher can project transparencies on the screens of the students’ workstations and can emphasize or indicate regions of interest on them by using the graphical tools offered by Hippocrates. Immediate results of the use of Hippocrates are the fast updating of the personnel in remote areas and the upgrading of the quality of the services they offer.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
In this paper we present a software tool for the realisation of the distance education service, that is the conduction of classes through the use of computers. The classes
are directed towards personnel in various areas and aim at the retraining and update of the personnel in subjects of special interest in their line of work. The conduction of
classes takes place, from and towards, remote regions with the aid of a computer network. Hippocrates is a flexible and easy-to-use application, which permits students, who sit in front of remotely situated workstations, to attend classes or seminars given by a teacher or expert, who can also be located in some remote geographical area. Hippocrates can be thought of as a distributed transparency projector. The teacher can project transparencies on the screens of the students’ workstations and can emphasize or indicate regions of interest on them by using the graphical tools offered by Hippocrates. Immediate results of the use of Hippocrates are the fast updating of the personnel in remote areas and the upgrading of the quality of the services they offer.
are directed towards personnel in various areas and aim at the retraining and update of the personnel in subjects of special interest in their line of work. The conduction of
classes takes place, from and towards, remote regions with the aid of a computer network. Hippocrates is a flexible and easy-to-use application, which permits students, who sit in front of remotely situated workstations, to attend classes or seminars given by a teacher or expert, who can also be located in some remote geographical area. Hippocrates can be thought of as a distributed transparency projector. The teacher can project transparencies on the screens of the students’ workstations and can emphasize or indicate regions of interest on them by using the graphical tools offered by Hippocrates. Immediate results of the use of Hippocrates are the fast updating of the personnel in remote areas and the upgrading of the quality of the services they offer.
Bouras, Christos; Spirakis, Paul
ICCI’93, Sudbury, Ontario, Canada, pp. 403-407, 1993.
Abstract | Links | BibTeX | Tags:
@conference{2857,
title = {The perfect and imperfect clocks approach to performance analysis of basic timestamp ordering in distributed databases},
author = {Christos Bouras and Paul Spirakis},
url = {https://telematics.upatras.gr/3253311/},
year = {1993},
date = {1993-05-01},
urldate = {1993-05-01},
booktitle = {ICCI’93, Sudbury, Ontario, Canada, pp. 403-407},
pages = {403 - 407},
abstract = {Locking and timestamping are two popular approaches to concurrency control in databases systems. Although more than a dozen analytic performance studies of locking techniques have recently appeared in the literature, analytic performance study of timestamp–based concurrency algorithms largely remains an unexplored area. This work presents a model of a distributed database system which provides the framework to study the performance of timestamp ordering concurrency control. We exhibit an analytical solution, which has been tested with extensive simulation. The accuracy seems to be very high. We assume perfect and also imperfect clocks for synchronization and quantify the way in which local clock inaccuracies affect the phenomenon of transaction conflicts. In particular, we derive a lot of interesting performance measures such as probability of abort, throughput and others.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Locking and timestamping are two popular approaches to concurrency control in databases systems. Although more than a dozen analytic performance studies of locking techniques have recently appeared in the literature, analytic performance study of timestamp–based concurrency algorithms largely remains an unexplored area. This work presents a model of a distributed database system which provides the framework to study the performance of timestamp ordering concurrency control. We exhibit an analytical solution, which has been tested with extensive simulation. The accuracy seems to be very high. We assume perfect and also imperfect clocks for synchronization and quantify the way in which local clock inaccuracies affect the phenomenon of transaction conflicts. In particular, we derive a lot of interesting performance measures such as probability of abort, throughput and others.
Bouras, Christos; Spirakis, Paul
Performance Models for Perfect and Imperfect Clocks on Timestamp Ordering in Distributed Databases Conference
MASCOTS’93, San Diego, California, USA, pp. 243-246, 1993.
Abstract | Links | BibTeX | Tags:
@conference{2856,
title = {Performance Models for Perfect and Imperfect Clocks on Timestamp Ordering in Distributed Databases},
author = {Christos Bouras and Paul Spirakis},
url = {https://telematics.upatras.gr/6258309/},
year = {1993},
date = {1993-01-01},
urldate = {1993-01-01},
booktitle = {MASCOTS’93, San Diego, California, USA, pp. 243-246},
pages = {243 - 246},
abstract = {This work presents a model of a distributed database system which provides the framework to study the performance of timestamp ordering concurrency control. We exhibit an analytical solution, which has been tested with extensive simulation. The accuracy seems to be very high. We assume perfect and also imperfect clocks for synchronization and quantify the way in which local clock inaccuracies affect the phenomenon of transaction conflicts.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
This work presents a model of a distributed database system which provides the framework to study the performance of timestamp ordering concurrency control. We exhibit an analytical solution, which has been tested with extensive simulation. The accuracy seems to be very high. We assume perfect and also imperfect clocks for synchronization and quantify the way in which local clock inaccuracies affect the phenomenon of transaction conflicts.
Bouras, Christos; Kapoulas, Vaggelis; Spirakis, Paul; Georgantas, T; Goutis, K
MIPL:An Image Processing Library for Medical Applications Conference
S/CAR’92, Baltimore, Maryland, USA, pp. 519-525, 1992.
@conference{2858,
title = {MIPL:An Image Processing Library for Medical Applications},
author = {Christos Bouras and Vaggelis Kapoulas and Paul Spirakis and T Georgantas and K Goutis},
url = {https://telematics.upatras.gr/3973306/},
year = {1992},
date = {1992-06-01},
urldate = {1992-06-01},
booktitle = {S/CAR’92, Baltimore, Maryland, USA, pp. 519-525},
pages = {519 - 525},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Bouras, Christos; Spirakis, Paul
The effect of clock drifts on the performance of distributed timestamp ordering Conference
3rd COMAD 91, Bombay, India, pp. 69-85, 1991.
Abstract | Links | BibTeX | Tags:
@conference{2860,
title = {The effect of clock drifts on the performance of distributed timestamp ordering},
author = {Christos Bouras and Paul Spirakis},
url = {https://telematics.upatras.gr/7832887/},
year = {1991},
date = {1991-12-01},
urldate = {1991-12-01},
booktitle = {3rd COMAD 91, Bombay, India, pp. 69-85},
pages = {69 - 85},
abstract = {Timestamp–based algorithms have been proposed to protect distributed database from inconsistencies during concurrent access. In such algorithms, transactions may reach a paricular site out of the order of their timestamps, due to unexpected network delays. This causes conflicts which the distributed concurrency control mechanism has to cope with. In this paper we analyze the essential features of the conflict phenomenon under the realistic assumption of the local site clocks out of total synchrony. We quantify the way in which local clock inaccuracies affect the phenomenon of transaction conflicts. In particular, we express the probability of order–reverse as a particular increasing function of the maximum clock drift.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Timestamp–based algorithms have been proposed to protect distributed database from inconsistencies during concurrent access. In such algorithms, transactions may reach a paricular site out of the order of their timestamps, due to unexpected network delays. This causes conflicts which the distributed concurrency control mechanism has to cope with. In this paper we analyze the essential features of the conflict phenomenon under the realistic assumption of the local site clocks out of total synchrony. We quantify the way in which local clock inaccuracies affect the phenomenon of transaction conflicts. In particular, we express the probability of order–reverse as a particular increasing function of the maximum clock drift.