Book Chapters
Konstantinos Tsachrelias; Chrysostomos-Athanasios Katsigiannis; Vasileios Kokkinos; Apostolos Gkamas; Christos Bouras; Philippos Pouyioutas
Dynamic Resource Allocation in Future Cellular Networks: DUDe, MIMO, and Beyond Book Chapter
In: IntechOpen Cellurar Communication System - The Evolution from 1G to 6G, pp. 1-19 (Ed.): IntechOpen, 2026.
Abstract | Links | BibTeX | Tags:
@inbook{nokey,
title = {Dynamic Resource Allocation in Future Cellular Networks: DUDe, MIMO, and Beyond},
author = {Konstantinos Tsachrelias and Chrysostomos-Athanasios Katsigiannis and Vasileios Kokkinos and Apostolos Gkamas and Christos Bouras and Philippos Pouyioutas },
editor = {Cellurar Communication System - The Evolution from 1G to 6G, IntechOpen, pp. 1-19},
url = {https://telematics.upatras.gr/1239986-1-2/},
year = {2026},
date = {2026-01-19},
urldate = {2026-01-19},
publisher = {IntechOpen},
abstract = {Resource allocation in 5G and beyond networks remains a demanding problem, largely driven by the rising need for higher data rates, reliable communication, and large-scale device connectivity. This chapter examines approaches that combine Downlink (DL)/Uplink (UL) Decoupling (DUDe) with Multiple-Input-MultipleOutput (MIMO) systems to improve spectral usage and reduce energy consumption.
DUDe is used to separate UL and DL associations so that User Equipment (UE) can connect to the most suitable Base Station (BS) for each direction, while MIMO techniques contribute additional spatial degrees of freedom through multiplexing and beamforming. The analysis also incorporates machine learning models that predict UE behavior and assist in adaptive decision-making, together with gametheoretic frameworks that coordinate UE association and resource competition in dense deployments. By bringing these elements together, the chapter outlines how future cellular systems can support more efficient and responsive resource management under realistic mobility and traffic conditions.},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
Resource allocation in 5G and beyond networks remains a demanding problem, largely driven by the rising need for higher data rates, reliable communication, and large-scale device connectivity. This chapter examines approaches that combine Downlink (DL)/Uplink (UL) Decoupling (DUDe) with Multiple-Input-MultipleOutput (MIMO) systems to improve spectral usage and reduce energy consumption.
DUDe is used to separate UL and DL associations so that User Equipment (UE) can connect to the most suitable Base Station (BS) for each direction, while MIMO techniques contribute additional spatial degrees of freedom through multiplexing and beamforming. The analysis also incorporates machine learning models that predict UE behavior and assist in adaptive decision-making, together with gametheoretic frameworks that coordinate UE association and resource competition in dense deployments. By bringing these elements together, the chapter outlines how future cellular systems can support more efficient and responsive resource management under realistic mobility and traffic conditions.
DUDe is used to separate UL and DL associations so that User Equipment (UE) can connect to the most suitable Base Station (BS) for each direction, while MIMO techniques contribute additional spatial degrees of freedom through multiplexing and beamforming. The analysis also incorporates machine learning models that predict UE behavior and assist in adaptive decision-making, together with gametheoretic frameworks that coordinate UE association and resource competition in dense deployments. By bringing these elements together, the chapter outlines how future cellular systems can support more efficient and responsive resource management under realistic mobility and traffic conditions.
Christos Bouras; Vasileios Kokkinos; Apostolos Gkamas; Evangelos Michos; Ioannis Sina; Ioannis Prokopiou; Foivos Allayiotis
An Introduction of Upcoming Radio Resource Management Techniques for 5G Networks Book Chapter
In: Advances in Engineering Research, Nova Science Publishers, vol. 46, Chapter 3, pp. 147-188, 2022.
Abstract | Links | BibTeX | Tags: DUDe
@inbook{4569,
title = {An Introduction of Upcoming Radio Resource Management Techniques for 5G Networks},
author = {Christos Bouras and Vasileios Kokkinos and Apostolos Gkamas and Evangelos Michos and Ioannis Sina and Ioannis Prokopiou and Foivos Allayiotis},
url = {https://telematics.upatras.gr/978-1-68507-427-2-161-201/},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
booktitle = {Advances in Engineering Research, Nova Science Publishers},
volume = {46},
pages = {147-188},
chapter = {3},
abstract = {5G networks are the next generation of mobile internet connectivity, that are able to offer vastly increased speeds, more reliable connections, minimal latency and more supported devices. 5G networks are expected to supercharge Internet of Things (IoT) technology, so as to provide the infrastructure needed in order to support and transfer large data amounts that will enable a smarter and more connected world. To this direction, 5G incorporates many technologies and mechanisms that aid towards the overall goal, such as Multiple-Input and Multiple-Output (MIMO), Downlink (DL) and Uplink (UL) Decoupling (DUDe) and Machine Learning (ML). These technologies can significantly help towards more efficient resource allocation inside the next generation networks, offering increased spectral efficiency and data rates, better signal coverage, reduced latencies and many more. In this chapter, we will provide insights over the aforementioned technologies through firstly a literature review and later on by analyzing their architecture and their models. We will explain how these technologies can be taken advantage of in order to support the 5G networks and why they are core components of future networks, as it is expected that also 5G and Beyond networks will capitalize on them.},
keywords = {DUDe},
pubstate = {published},
tppubtype = {inbook}
}
5G networks are the next generation of mobile internet connectivity, that are able to offer vastly increased speeds, more reliable connections, minimal latency and more supported devices. 5G networks are expected to supercharge Internet of Things (IoT) technology, so as to provide the infrastructure needed in order to support and transfer large data amounts that will enable a smarter and more connected world. To this direction, 5G incorporates many technologies and mechanisms that aid towards the overall goal, such as Multiple-Input and Multiple-Output (MIMO), Downlink (DL) and Uplink (UL) Decoupling (DUDe) and Machine Learning (ML). These technologies can significantly help towards more efficient resource allocation inside the next generation networks, offering increased spectral efficiency and data rates, better signal coverage, reduced latencies and many more. In this chapter, we will provide insights over the aforementioned technologies through firstly a literature review and later on by analyzing their architecture and their models. We will explain how these technologies can be taken advantage of in order to support the 5G networks and why they are core components of future networks, as it is expected that also 5G and Beyond networks will capitalize on them.
Christos Bouras; Eirini Barri; Apostolos Gkamas; Nikos Karacapilidis; Dimitris Karadimas; Georgios Kournetas; Yiannis Panaretou
In: Springer Book of SIMULTECH 2020, 2021.
Abstract | Links | BibTeX | Tags:
@inbook{4498,
title = {A Novel Approach to Energy Management in Large Passenger and Cruise Ships: Integrating Simulation and Machine Learning Models},
author = {Christos Bouras and Eirini Barri and Apostolos Gkamas and Nikos Karacapilidis and Dimitris Karadimas and Georgios Kournetas and Yiannis Panaretou},
url = {https://telematics.upatras.gr/simultech2020_id32_cameraready_aiscs_submitted-updated-final/},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
booktitle = {Springer Book of SIMULTECH 2020},
abstract = {It has been broadly admitted that the prediction of energy consumption in large passenger and cruise ships is a complex and challenging issue. Aiming to address it, this chapter reports on the development of a novel approach that builds on a sophisticated agent-based simulation model, which takes into account diverse parameters such as the size, type and behavior of the different categories of passengers onboard, the energy consuming facilities and devices of a ship, spatial data concerning the layout of a ship’s decks, and alternative ship operation modes. According to the proposed approach, outputs obtained from multiple simulation runs are then exploited by prominent Machine Learning algorithms to extract meaningful patterns between the composition of passengers and the corresponding energy demands in a ship. In this way, our approach is able to predict alternative energy consumption scenarios and trigger meaningful insights concerning the overall energy management in a ship. Overall, the proposed approach may handle the underlying uncertainty by blending the process centric character of a simulation model and the data-centric character of Machine Learning algorithms. The chapter also describes the overall architecture of the proposed solution, which is based on the microservices approach.},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
It has been broadly admitted that the prediction of energy consumption in large passenger and cruise ships is a complex and challenging issue. Aiming to address it, this chapter reports on the development of a novel approach that builds on a sophisticated agent-based simulation model, which takes into account diverse parameters such as the size, type and behavior of the different categories of passengers onboard, the energy consuming facilities and devices of a ship, spatial data concerning the layout of a ship’s decks, and alternative ship operation modes. According to the proposed approach, outputs obtained from multiple simulation runs are then exploited by prominent Machine Learning algorithms to extract meaningful patterns between the composition of passengers and the corresponding energy demands in a ship. In this way, our approach is able to predict alternative energy consumption scenarios and trigger meaningful insights concerning the overall energy management in a ship. Overall, the proposed approach may handle the underlying uncertainty by blending the process centric character of a simulation model and the data-centric character of Machine Learning algorithms. The chapter also describes the overall architecture of the proposed solution, which is based on the microservices approach.
Christos Bouras; Eirini Barri; Apostolos Gkamas; Nikos Karacapilidis; Dimitris Karadimas; Giorgos Kournetas; Yiannis Panaretou
An agent-based simulation model for energy saving in large passenger and cruise ships Book Chapter
In: CRC Press, 2021.
Abstract | Links | BibTeX | Tags:
@inbook{4497,
title = {An agent-based simulation model for energy saving in large passenger and cruise ships},
author = {Christos Bouras and Eirini Barri and Apostolos Gkamas and Nikos Karacapilidis and Dimitris Karadimas and Giorgos Kournetas and Yiannis Panaretou},
url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/Chapter5.pdf},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
booktitle = {CRC Press},
abstract = {Undoubtedly, energy saving is of paramount importance in the shipping industry, as far as both the protection of environment and the reduction of the associated operating costs are concerned. In this direction, the
International Maritime Organization aims to reduce ship emissions by at least 50% by 2050, while ships to be built by 2025 are expected to be a massive 30% more energy efficient than those built some years ago [IMO,
2018].},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
Undoubtedly, energy saving is of paramount importance in the shipping industry, as far as both the protection of environment and the reduction of the associated operating costs are concerned. In this direction, the
International Maritime Organization aims to reduce ship emissions by at least 50% by 2050, while ships to be built by 2025 are expected to be a massive 30% more energy efficient than those built some years ago [IMO,
2018].
International Maritime Organization aims to reduce ship emissions by at least 50% by 2050, while ships to be built by 2025 are expected to be a massive 30% more energy efficient than those built some years ago [IMO,
2018].
Christos Bouras; Anastasia Kollia; Andreas Papazois
Exploring SDN & NFV in 5G Using ONOS & POX Conytollers Book Chapter
In: Research Anthology on Developing and Optimizing 5G Networks and the Impact on Society, IGI Global 2021, Chapter 9, pp. 187-203, 2021.
Abstract | Links | BibTeX | Tags:
@inbook{4513,
title = {Exploring SDN & NFV in 5G Using ONOS & POX Conytollers},
author = {Christos Bouras and Anastasia Kollia and Andreas Papazois},
url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/Exploring-SDN-NFV-in-5G-Using-ONOS-POX-Controllers.pdf},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
booktitle = {Research Anthology on Developing and Optimizing 5G Networks and the Impact on Society, IGI Global 2021},
pages = {187-203},
chapter = {9},
abstract = {This article describes how novel functionalities will take advantage of the cloud networking and will gradually replace the existing infrastructure of mobile networks with a virtualized one. Two technologies, namely software defined networking (SDN) and network function virtualization (NFV), offer their important benefits and a combination of them is an answer to the demands raised, such as central office re-architected as a data center (CORD). Open network operating system (ONOS) and POX are SDN controllers and offer an option to combine SDN and NFV addressing many ongoing problems in the field of mobile networks. In this paper, technologies and both controllers are compared and contrasted. Indicative cases of topologies are simulated and help evaluating both controllers. According to the experimental findings, ONOS is one of the most important controllers for practical, theoretical, research and educational purposes, while POX is a useful and simpler controller for other educative applications.},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
This article describes how novel functionalities will take advantage of the cloud networking and will gradually replace the existing infrastructure of mobile networks with a virtualized one. Two technologies, namely software defined networking (SDN) and network function virtualization (NFV), offer their important benefits and a combination of them is an answer to the demands raised, such as central office re-architected as a data center (CORD). Open network operating system (ONOS) and POX are SDN controllers and offer an option to combine SDN and NFV addressing many ongoing problems in the field of mobile networks. In this paper, technologies and both controllers are compared and contrasted. Indicative cases of topologies are simulated and help evaluating both controllers. According to the experimental findings, ONOS is one of the most important controllers for practical, theoretical, research and educational purposes, while POX is a useful and simpler controller for other educative applications.
Christos Bouras; Vaggelis Kapoulas; Enea Tsanai
Performance Evaluation of Routing Mechanisms for VANETs in Urban Areas Book Chapter
In: Algorithms, Probability, Networks, and Games: Scientific Papers and Essays, pp. 133-135, 2015.
Abstract | Links | BibTeX | Tags:
@inbook{4105,
title = {Performance Evaluation of Routing Mechanisms for VANETs in Urban Areas},
author = {Christos Bouras and Vaggelis Kapoulas and Enea Tsanai},
url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/Spirakis-Festschrift-3A978-3-319-24024-4-bouras.pdf},
year = {2015},
date = {2015-01-01},
urldate = {2015-01-01},
booktitle = {Algorithms, Probability, Networks, and Games: Scientific Papers and Essays},
pages = {133-135},
abstract = {Mobile Ad hoc Networks (MANETs) and especially Vehicular Ad hoc Networks (VANETs) have recently gained large interest and their performance is heavily studied. A great challenge in VANETs, especially in an urban setting, is the routing scheme used and the subsequent performance obtained. This work presents an experimental performance evaluation of routing mechanisms in VANETs, using simulation, within an urban Manhattan grid like environment. It also describes and evaluates an enhancement of the Greedy Perimeter Stateless Routing (GPSR) protocol that takes into account the motion of the vehicles and the nature of the urban environment. The simulation results demonstrate that the proposed enhancement to the GPSR protocol manages to significantly increase the delivery ratio without increasing the power consumption; nevertheless, in some cases the improvement on delivery ratio is achieved at the expense of slightly increased end-to-end delay.},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
Mobile Ad hoc Networks (MANETs) and especially Vehicular Ad hoc Networks (VANETs) have recently gained large interest and their performance is heavily studied. A great challenge in VANETs, especially in an urban setting, is the routing scheme used and the subsequent performance obtained. This work presents an experimental performance evaluation of routing mechanisms in VANETs, using simulation, within an urban Manhattan grid like environment. It also describes and evaluates an enhancement of the Greedy Perimeter Stateless Routing (GPSR) protocol that takes into account the motion of the vehicles and the nature of the urban environment. The simulation results demonstrate that the proposed enhancement to the GPSR protocol manages to significantly increase the delivery ratio without increasing the power consumption; nevertheless, in some cases the improvement on delivery ratio is achieved at the expense of slightly increased end-to-end delay.
Christos Bouras; Vasileios Kokkinos; Georgios Diles; Lefteris Topaloglou; Christos Bouras; Andrej Kos; Andrew Frank
IMPACT OF BROADBAND ON ECONOMY Book Chapter
In: Policies and Tools for Efficient Design of Broadband Development, Chapter 2, pp. 28-42, 2014.
Abstract | Links | BibTeX | Tags:
@inbook{4067,
title = {IMPACT OF BROADBAND ON ECONOMY},
author = {Christos Bouras and Vasileios Kokkinos and Georgios Diles and Lefteris Topaloglou and Christos Bouras and Andrej Kos and Andrew Frank},
url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/SIVA-paper-Chapter-2.pdf},
year = {2014},
date = {2014-01-01},
urldate = {2014-01-01},
booktitle = {Policies and Tools for Efficient Design of Broadband Development},
pages = {28-42},
chapter = {2},
abstract = {<p>In this chapter, we investigate the impact of broadband on the growth and employment in SEE countries, namely Austria, Bulgaria, the former Yugoslav Republic of Macedonia (FYROM), Greece, Montenegro, Slovenia. Specifically, we define the macroeconomic evidence required for the analysis. We then enforce regression analysis on data collected by the respective countries in order to find the correlation between broadband, growth and employment. The period of the examination was set to be the last decade in order to obtain an extended amount of data, and take into account possible influences on the results by the economic crisis and the subsequent recession of the last years in the area. We also estimate the cost savings to companies and the state by the usage of broadband-based e-government services. We then forecast these benefits to 2015 when the respective countries are expected to have reached the e-government usage level which is set by the European digital agenda (Digital agenda, 2013).</p>},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
<p>In this chapter, we investigate the impact of broadband on the growth and employment in SEE countries, namely Austria, Bulgaria, the former Yugoslav Republic of Macedonia (FYROM), Greece, Montenegro, Slovenia. Specifically, we define the macroeconomic evidence required for the analysis. We then enforce regression analysis on data collected by the respective countries in order to find the correlation between broadband, growth and employment. The period of the examination was set to be the last decade in order to obtain an extended amount of data, and take into account possible influences on the results by the economic crisis and the subsequent recession of the last years in the area. We also estimate the cost savings to companies and the state by the usage of broadband-based e-government services. We then forecast these benefits to 2015 when the respective countries are expected to have reached the e-government usage level which is set by the European digital agenda (Digital agenda, 2013).</p>
Christos Bouras; Savvas Charalambides; Michalis Drakoulelis; G Kioumourtzis; Kostas Stamos
Enhancing simulation environment with TRAFIL Book Chapter
In: Simulation Technologies in Networking and Communications: Selecting the Best Tool for the Test, Chapter 14, pp. 391-415, CRC Press, 2014.
Abstract | Links | BibTeX | Tags:
@inbook{3435,
title = {Enhancing simulation environment with TRAFIL},
author = {Christos Bouras and Savvas Charalambides and Michalis Drakoulelis and G Kioumourtzis and Kostas Stamos},
url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/48386_RevisedManuscript.pdf},
year = {2014},
date = {2014-01-01},
urldate = {2014-01-01},
booktitle = {Simulation Technologies in Networking and Communications: Selecting the Best Tool for the Test},
pages = {391-415},
publisher = {CRC Press},
chapter = {14},
organization = {CRC Press},
abstract = {<p>This chapter presents TRAFIL, a comprehensive tool for enhancing execution of simulations. It provides an overview of the tool, its architecture and its functionalities. It explains how TRAFIL en-hances the entire simulation procedure including graphical setup of simulation scenarios, automated execution of simulations, flexible handling and storage of simulation trace files and presentation of plots based on processing of simulation results. It presents the concept of metafiles that provides TRAFIL with the flexibility to handle heterogeneous simulation environments. The chapter also compares TRAFIL performance with other similar tools and finds that it offers significantly im-proved performance. It therefore concludes that TRAFIL offers both a rich set of simulation en-hancement functionalities and top performance.</p>},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
<p>This chapter presents TRAFIL, a comprehensive tool for enhancing execution of simulations. It provides an overview of the tool, its architecture and its functionalities. It explains how TRAFIL en-hances the entire simulation procedure including graphical setup of simulation scenarios, automated execution of simulations, flexible handling and storage of simulation trace files and presentation of plots based on processing of simulation results. It presents the concept of metafiles that provides TRAFIL with the flexibility to handle heterogeneous simulation environments. The chapter also compares TRAFIL performance with other similar tools and finds that it offers significantly im-proved performance. It therefore concludes that TRAFIL offers both a rich set of simulation en-hancement functionalities and top performance.</p>
Christos Bouras; Antonios Alexiou; Andreas Papazois; Vasileios Kokkinos; George Tsichritzis
Multimedia Broadcasting in LTE Networks Book Chapter
In: Access Environments and Quality of Service Provisioning: Solutions and Applications, Chapter 11, pp. 269-289, IGI Global, 2012.
Abstract | Links | BibTeX | Tags: LTE, MBMS
@inbook{3145,
title = {Multimedia Broadcasting in LTE Networks},
author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and George Tsichritzis},
url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/Multimedia-Broadcasting-in-LTE-Networks.pdf},
year = {2012},
date = {2012-01-01},
urldate = {2012-01-01},
booktitle = {Access Environments and Quality of Service Provisioning: Solutions and Applications},
pages = {269-289},
publisher = {IGI Global},
chapter = {11},
organization = {IGI Global},
abstract = {Long Term Evolution (LTE) constitutes the latest step before the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile communications. To support Multimedia Broadcast/Multicast Services (MBMS), LTE offers the functionality to transmit MBMS over Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted from multiple cells for a given duration. In MBSFN transmissions, the achieved Spectral Efficiency (SE) is mainly determined by the Modulation and Coding Scheme (MCS) selected. This study proposes and evaluates four approaches for the selection of the MCS that will be utilized for the transmission of the MBSFN data. The evaluation of the approaches is performed for different users? distribution and from SE perspective. Based on the SE measurement, we determine the approach that either maximizes or achieves a target SE for the corresponding users? distribution.},
keywords = {LTE, MBMS},
pubstate = {published},
tppubtype = {inbook}
}
Long Term Evolution (LTE) constitutes the latest step before the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile communications. To support Multimedia Broadcast/Multicast Services (MBMS), LTE offers the functionality to transmit MBMS over Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted from multiple cells for a given duration. In MBSFN transmissions, the achieved Spectral Efficiency (SE) is mainly determined by the Modulation and Coding Scheme (MCS) selected. This study proposes and evaluates four approaches for the selection of the MCS that will be utilized for the transmission of the MBSFN data. The evaluation of the approaches is performed for different users? distribution and from SE perspective. Based on the SE measurement, we determine the approach that either maximizes or achieves a target SE for the corresponding users? distribution.
Christos Bouras; Kostas Stamos
Security issues for multi - domain resource reservation Book Chapter
In: Network Security, Administration, and Management: Advancing Technologies and Practises, pp. 38 - 50, IGI Global, 2011.
Abstract | Links | BibTeX | Tags:
@inbook{3142,
title = {Security issues for multi - domain resource reservation},
author = {Christos Bouras and Kostas Stamos},
url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/Security-Issues-for-Multi-Domain-Resource-Reservation.pdf},
year = {2011},
date = {2011-01-01},
urldate = {2011-01-01},
booktitle = {Network Security, Administration, and Management: Advancing Technologies and Practises},
pages = {38 - 50},
publisher = {IGI Global},
organization = {IGI Global},
abstract = {In this chapter, we deal with the issue of security regarding components that are responsible for provisioning multi-domain network services, either automatically or through some form of administrator interaction. It is evident that a malicious compromise of such a component would have far-reaching implications for the stability of the network. Furthermore, trust between cooperating domains is a delicate issue and each partner in the multi-domain federation has to have some guarantees that peers in the service are not going to be security compromised. We enumerate some of the related dangers and propose ways to limit the attack surface, reduce the intrusion possibilities, and guarantee the quick resolution of any successful violations. The issue of security is studied in two main parts: Inter-domain security, for the communication between domains and the successful negotiation of resource reservations and intra-domain security, for the internal communications within a domain for the initiation of a resource reservation and its actual realization in the network devices. Resource reservation is studied both on the level of IP services based on Differentiated Services architectures, and on the level of dynamic circuit reservation based on Layer 2 technologies. The chapter is completed with a case study on the authentication and authorization framework designed in the context of a pan-european network resource reservation service, in the Geant academic and research network.</p>},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
In this chapter, we deal with the issue of security regarding components that are responsible for provisioning multi-domain network services, either automatically or through some form of administrator interaction. It is evident that a malicious compromise of such a component would have far-reaching implications for the stability of the network. Furthermore, trust between cooperating domains is a delicate issue and each partner in the multi-domain federation has to have some guarantees that peers in the service are not going to be security compromised. We enumerate some of the related dangers and propose ways to limit the attack surface, reduce the intrusion possibilities, and guarantee the quick resolution of any successful violations. The issue of security is studied in two main parts: Inter-domain security, for the communication between domains and the successful negotiation of resource reservations and intra-domain security, for the internal communications within a domain for the initiation of a resource reservation and its actual realization in the network devices. Resource reservation is studied both on the level of IP services based on Differentiated Services architectures, and on the level of dynamic circuit reservation based on Layer 2 technologies. The chapter is completed with a case study on the authentication and authorization framework designed in the context of a pan-european network resource reservation service, in the Geant academic and research network.</p>
Christos Bouras; Andreas Papazois; Vasileios Kokkinos; Georgia Tseliou
Forward Error Correction for Reliable e-MBMS Transmissions in LTE Networks Book Chapter
In: Cellurar Networks, pp. 353 - 374, InTech, 2011.
Links | BibTeX | Tags: FEC, LTE, MBMS
@inbook{3144,
title = {Forward Error Correction for Reliable e-MBMS Transmissions in LTE Networks},
author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Georgia Tseliou},
url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/7910FEC.pdf},
year = {2011},
date = {2011-01-01},
urldate = {2011-01-01},
booktitle = {Cellurar Networks},
pages = {353 - 374},
publisher = {InTech},
organization = {InTech},
keywords = {FEC, LTE, MBMS},
pubstate = {published},
tppubtype = {inbook}
}
Christos Bouras; Vassilis Poulopoulos; Panagiotis Silintziris
Learning from user’s behavior - A technique for personalized news search supporting result cashing Book Chapter
In: Information Extraction from the Internet, Chapter 11, pp. 177-196, iConcept Press, 2011.
@inbook{3146,
title = {Learning from user’s behavior - A technique for personalized news search supporting result cashing},
author = {Christos Bouras and Vassilis Poulopoulos and Panagiotis Silintziris},
url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/1345100715050620.pdf},
year = {2011},
date = {2011-01-01},
urldate = {2011-01-01},
booktitle = {Information Extraction from the Internet},
pages = {177-196},
publisher = {iConcept Press},
chapter = {11},
organization = {iConcept Press},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
Christos Bouras; Vaggelis Kapoulas; Petros Ganos
Broadband Infrastructures as a Common and the Role of Local Governments Book Chapter
In: Public Sector Reform Using Information Technologies : Trandforming Policy into Practice, pp. 298-319, IGI Global, 2011.
@inbook{3141,
title = {Broadband Infrastructures as a Common and the Role of Local Governments},
author = {Christos Bouras and Vaggelis Kapoulas and Petros Ganos},
url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/Broadband-Infrastructures-as-a-Common-and-the-Role-of-Local-Governments.pdf},
year = {2011},
date = {2011-01-01},
urldate = {2011-01-01},
booktitle = {Public Sector Reform Using Information Technologies : Trandforming Policy into Practice},
pages = {298-319},
publisher = {IGI Global},
organization = {IGI Global},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
Conferences
Christos Bouras; Paul Spirakis
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.
Christos Bouras; Paul Spirakis
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.
Christos Bouras; Vaggelis Kapoulas; Paul Spirakis; T Georgantas; K Goutis
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}
}
Christos Bouras; Paul Spirakis
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.
Christos Bouras; Paul Spirakis; J Garofalakis; G Papoutsopoulos; P Basiroglou
RECPHONE: A new environment for medical remote expert consultation Conference
EuroPACS’91, 9th International Meeting, Berlin, Germany, pp. 22-23, 1991.
@conference{2859,
title = {RECPHONE: A new environment for medical remote expert consultation},
author = {Christos Bouras and Paul Spirakis and J Garofalakis and G Papoutsopoulos and P Basiroglou},
url = {https://telematics.upatras.gr/7799recphone_bouras/},
year = {1991},
date = {1991-07-01},
urldate = {1991-07-01},
booktitle = {EuroPACS’91, 9th International Meeting, Berlin, Germany, pp. 22-23},
pages = {22 - 23},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Christos Bouras; Paul Spirakis
5th International Symposium on Computers and Information Sciences- ISCIS V, Volume II, Cappadocia, Nevsehir, Turkey, pp. 719-727, 1990.
@conference{2861,
title = {Simplified performance models of the reordering issue in timestamp ordering concurrency control in distributed databases},
author = {Christos Bouras and Paul Spirakis},
url = {https://telematics.upatras.gr/8684simplified_bouras/},
year = {1990},
date = {1990-10-01},
urldate = {1990-10-01},
booktitle = {5th International Symposium on Computers and Information Sciences- ISCIS V, Volume II, Cappadocia, Nevsehir, Turkey, pp. 719-727},
pages = {719 - 727},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Christos Bouras; Paul Spirakis; Vasilis Triantafillou; J Garofalakis
Queueing Delays in Buffered Multistage Interconnection Networks Conference
ACM SIGMETRICS Conference 1987, Banff, Alberta, Canada, pp. 111-121, 1987.
Abstract | Links | BibTeX | Tags:
@conference{2862,
title = {Queueing Delays in Buffered Multistage Interconnection Networks},
author = {Christos Bouras and Paul Spirakis and Vasilis Triantafillou and J Garofalakis},
url = {https://telematics.upatras.gr/5267queueing_delays_bouras/},
year = {1987},
date = {1987-05-01},
urldate = {1987-05-01},
booktitle = {ACM SIGMETRICS Conference 1987, Banff, Alberta, Canada, pp. 111-121},
pages = {111 - 121},
abstract = {Our Work with the analysis of the queueing delays of buffered multistage banyan networks of multiprocessors. We provide tight upper bounds on the mean delays of the second stage and beyond, in the case of infinite buffers. Our results are validated by simulations performed on a network simulator constructed by us. The analytic work for network stages beyond the first, provides a partial answer to open problems posed by previous research. },
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Our Work with the analysis of the queueing delays of buffered multistage banyan networks of multiprocessors. We provide tight upper bounds on the mean delays of the second stage and beyond, in the case of infinite buffers. Our results are validated by simulations performed on a network simulator constructed by us. The analytic work for network stages beyond the first, provides a partial answer to open problems posed by previous research.