Publications

@inbook{3137,

title = {Providing quality end-to-end videoconference services in IP networks},

author = {Christos Bouras and Kostas Stamos},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/2414VTIA_NovaScience2009_Bouras.pdf},

year  = {2010},

date = {2010-01-01},

urldate = {2010-01-01},

booktitle = {Videoconferencing: Technology, Impact and Applications},

pages = {111 - 122},

publisher = {Nova Science Publishers},

chapter = {5},

organization = {Nova Science Publishers},

abstract = {<p>The development of quality and user satisfying videoconference applications at a low cost has been hindered in the past by, among other reasons, low quality connections and a difficulty for the average user to establish end-to-end connections without hassle. In this chapter, we describe some of the latest methods and developments that overcome these problems. In particular, we discuss ways to make establishment of universal videoconference connections easier by overcoming the problem of participants that reside behind NAT routers, by deploying new protocols at the application or even the network layer. An example of the former case is the development of establishment protocols specifically designed for this purpose, while an example for the latter case is the deployment of IPv6, which aims to make NAT deployments obsolete. Furthermore, we discuss efforts to provide targeted support for quality of experience in networks that support some kind of traffic classification through the usage of dynamic mechanisms and dynamic network re-configurations. Apart from describing the state of the art in the aforementioned areas, we provide detailed insight in specific research efforts that have taken place and assess their results in the overall user experience.</p>},

keywords = {},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3130,

title = {Adaptive multimedia transmission over the Internet},

author = {Christos Bouras and Apostolos Gkamas},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/4416adaptive.pdf},

year  = {2010},

date = {2010-01-01},

urldate = {2010-01-01},

booktitle = {Chapter 20, Selected Topics in Communication Networks and Distributed Systems},

pages = {589 - 606},

publisher = {World Scientific},

organization = {World Scientific},

abstract = {The Internet is a heterogeneous network environment and the network resources that are available to multimedia applications can be modified very quickly. Multimedia applications must have the capability to adapt their operation to network changes. In order to add adaptation characteristics to multimedia applications, we can use techniques both at the network and application layers. Adaptive multimedia transmission techniques have the capability to transmit multimedia data over heterogeneous networks and adapt media transmission to network changes. In order to provide adaptive multimedia transmission, mechanisms to monitor the network conditions and mechanisms to adapt the transmission of the data to the network changes must be implemented. This chapter concentrates on the architecture and design issues of adaptive multimedia techniques that provide the capability to transmit multimedia data over heterogeneous networks and adapt the transmission of the multimedia data to the network changes.},

keywords = {},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3139,

title = {Radio Resource Management for E-MBMS Transmissions towards LTE},

author = {Christos Bouras and Antonios Alexiou and Vasileios Kokkinos},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/1335K10322_C009.pdf},

year  = {2010},

date = {2010-01-01},

urldate = {2010-01-01},

booktitle = {Evolved Cellular Network Planning and Optimization for UMTS and LTE},

pages = {331 - 360},

publisher = {Auerbach Publications, CRC Press, Taylor and Francis Group},

chapter = {9},

organization = {Auerbach Publications, CRC Press, Taylor and Francis Group},

abstract = {<p>Long Term Evolution (LTE) constitutes a key standard that paves the way for the future mobile broadband landscape envisioned by 4th Generation (4G) wireless networks. Actu- ally, LTE addresses the emerging trend for the mass provision of rich multimedia services, such as Mobile TV, in a more power and spectral e±cient way than its predecessors. To this direction, the Evolved - Multimedia Broadcast/Multicast Service (E-MBMS) frame- work is envisaged to play an instrumental role for the LTE proliferation in mobile. E-MBMS constitutes the evolutionary successor of MBMS, which was introduced in the Release 6 of Universal Mobile Telecommunication System (UMTS). MBMS is designed in order to deliver multimedia data from a single source entity to multiple destinations. However, downlink ca- pacity in such networks is limited by base station transmission power. As an aftermath, in MBMS e±cient power allocation techniques should be implemented so as to ensure the mass provision of multimedia applications to mobile users. This chapter presents several techniques and mechanisms used today for MBMS power optimization in next generation cellular networks.</p>},

keywords = {LTE, MBMS, Power Control},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3132,

title = {Squeak Etoys: Interactive and Collaborative Learning Environment},

author = {Christos Bouras and Vassilis Poulopoulos and Vassilis Tsogkas},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/9805978-1-60566-368-5_ch037.pdf},

year  = {2010},

date = {2010-01-01},

urldate = {2010-01-01},

booktitle = {Handbook of Research on SocialInteraction Technologies and Collaboration Software: Concepts and Trends},

pages = {417 - 427},

publisher = {IGI Global},

chapter = {37},

organization = {IGI Global},

abstract = {<p>Squeak Etoys is a free software program and media-rich authoring system with a user-friendly visual interface. The software is designed to help six to twelve year-old children learn through interaction and collaboration; it comes preinstalled on XO laptop computers distributed by the One Laptop Per Child Foundation. The goal of the One Laptop Per Child initiative is to create novel educational opportunities for the world?s children by providing each child with a book-size, light and portable computer for personal use at school and at home. This chapter elaborates on the educational dimensions of the XO laptop and the Etoys environment developed to empower teachers and students with the capacity for creative learning, exploration, interaction, and collaboration. The authors focus on how the hardware and software capabilities of XO laptops can be utilized to allow children to interact, work together on projects, and engage in computer simulations and games while learning mathematics, physics, chemistry, and geometry.</p>},

keywords = {},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3134,

title = {Exploiting Virtual Environments and Web2.0 Immersive Worlds to Support Collaborative e-Learning Communities},

author = {Christos Bouras and Thrasivoulos Tsiatsos and Eleftheria Giannaka},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/ADVANCED-ISSUES-IN-THE-DESIGN-OF-A-PLATFORM-FOR-EDUCATIONAL-VIRTUAL-ENVIRONMENTS.pdf},

year  = {2010},

date = {2010-01-01},

urldate = {2010-01-01},

booktitle = {Novel Approaches in Web - Based Learning Technologies: Tools for ModernTeaching},

pages = {20 - 45},

publisher = {IGI Global},

chapter = {2},

organization = {IGI Global},

abstract = {<p>The main goal of this chapter is to facilitate educational designers and developers by providing a point of reference for making decisions on how to incorporate 3D environments into the applications they develop as well as for extending their capabilities by integrating more functionality. Therefore, this chapter presents the design principles for virtual spaces, which aim at supporting multi-user communication in web-based learning communities. In addition the implementation of these principles is presented using as point of reference EVE Training Area. This environment constitutes a three-dimensional space where participants, represented by 3D humanoid avatars, have the ability to use a variety of 3D e-collaboration tools for learning together. Furthermore, this chapter presents how these principles could be used as criteria for validating and extending ready Web2.0 Immersive worlds for supporting collaborative e-learning. Finally, collaborative e-learning usage scenarios that could be realized by exploiting collaborative virtual environments are described.</p>},

keywords = {},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3129,

title = {Congestion Control for Multicast Transmission over UMTS},

author = {Christos Bouras and Antonios Alexiou and Andreas Papazois},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/9346final_chapter_with_pics.pdf},

year  = {2009},

date = {2009-01-01},

urldate = {2009-01-01},

booktitle = {Wireless Quality of Service: Techniques, Standards and Applications},

pages = {291 - 312},

publisher = {Auerbach Publications, Taylor & Francis Group},

chapter = {10},

organization = {Auerbach Publications, Taylor & Francis Group},

abstract = {<p>In this chapter, we present a novel mechanism for the multicast congestion control over Universal Mobile Telecommunications System (UMTS) networks. The proposed mechanism is based on the well known TCP-Friendly Multicast Congestion Control (TFMCC) scheme. TFMCC is an equation-based multicast congestion control mechanism intended to scale to groups of several thousand receivers. It is based on the concept of Current Limiting Receiver (CLR). The CLR is the receiver that the sender believes currently has the lowest expected throughput of the multicast group. The key challenge in the design of the new scheme lies in extending TFMCC in order to support the UMTS Terrestrial Radio-Access Network (UTRAN). Our major contribution is that the TFMCC mechanism was improved in order to cope with the packet losses caused by either the temporary or the permanent degradation of the wireless channel. One of the major advantages of the proposed scheme is that it introduces minor modifications in the UMTS nodes with respect to the computing power of the mobile terminals. Finally, we implement our approach in the ns-2 network simulator and we evaluate it under various conditions. The simulation results are presented along with their analysis.</p>},

keywords = {Congestion Control, UMTS},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3128,

title = {An Integrated Architecture for Supporting Vocational Training},

author = {Christos Bouras and Thrasivoulos Tsiatsos and Eleftheria Giannaka},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/172311.pdf},

year  = {2008},

date = {2008-01-01},

urldate = {2008-01-01},

booktitle = {Architecture Solutions for e-Learning Systems},

pages = {197 - 218},

publisher = {IDEA Group Publishing},

organization = {IDEA Group Publishing},

abstract = {<p>E-learning and Web-based training have evolved over time from a newborn trend for complementing the learning process to a major form of education and training for supporting mainly geographically scattered users. The basic aim of this chapter is the description of a platform for open and distance training, which is mainly focused at supporting the needs of Vocational Training Centers as well as of institutions providing life-long adult training and learning. In particular, the issues that this chapter focuses on are vocational education and training characteristics and requirements, the current situation and technological trends in ICT-supported VET, the development framework and processes while it also proposes basic vocational training services and the system architecture of the integrated platform. The presented platform aims to provide services of both synchronous and asynchronous and collaborative distance learning.</p>},

keywords = {},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3127,

title = {Metropolitan Broadband Networks: Design and implementation aspects and business models},

author = {Christos Bouras and Dimitris Primpas and Antonios Alexiou and J Papagiannopoulos},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/4113Dwived196.pdf},

year  = {2008},

date = {2008-01-01},

urldate = {2008-01-01},

booktitle = {Global Diffusion of Broadband Data Transmission: Factors Affecting the Adoption, Usage and Economics of Broadband},

volume = {1},

pages = {196 - 210},

publisher = {IDEA Group Publishing},

chapter = {XIII},

organization = {IDEA Group Publishing},

abstract = {<p>This chapter presents the design principles that cover the implementation of broadband infrastructure in the region of Western Greece, by examining all the necessary parameters that arise while implementing such a critical developmental project. The broadband infrastructure that is deployed is either based on optical fiber (on big municipalities) or on wireless systems (OFDM based and WiFi cells). Furthermore, we present as two case studies, all issues of the designing of the Metropolitan Area Network of Patras, the third biggest city of Greece and the Wireless Access Network of Messatida. The major target of the broadband networks is to interconnect the buildings of the public sector in the city and also deploy infrastructure (fibers or wireless systems) that will create conditions of competition in providing both access and content services in advantage of the end consumer. The usage of the broadband infrastructure by service providers will be based on the open availability of the infrastructure in a cost effective way. Finally, we present the main characteristics of a proposed business plan that ensures financial viability of the broadband infrastructure and guarantees the administration, growth, and exploitation of infrastructure.</p>},

keywords = {},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3126,

title = {Using Open Source to Building and Accessing Learning Objects and Online Courses},

author = {Christos Bouras and Maria Nani},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/758409Bouras_Nani.pdf},

year  = {2007},

date = {2007-01-01},

urldate = {2007-01-01},

booktitle = {Open Source for Knowledge and LearningManagement: Strategies beyond Tools},

pages = {268 - 298},

publisher = {IDEA Group Publishing},

organization = {IDEA Group Publishing},

abstract = {As e-learning continuously gains the interest of the scientific community, industry, and government, a wide variety of learning technology products have been incorporated into the marketplace. Advances in information and communication technologies are in favor of the incorporation of innovative services and functionalities in such systems, though content creation and delivery remain the two key factors in any e-learning system. Therefore, in this chapter, we present the design and implementation of a tool targeted at building and accessing learning objects and online courses through the Web. This tool aims to facilitate instructors and trainers to easily develop accessible, reusable, and traceable learning content that can meet their distant students? needs for anytime and anyplace learning. Learners are able to access learning content, in addition to consulting, at any time, reports on their interactions within a course and get support by subject experts. Furthermore, all users can request to upgrade their role in the system and, thus, actively participate in the learning process. Special attention has been paid on the utilization of reliable and qualitative open source technologies and Web standards so that the proposed solution can form an easily accessible system.},

keywords = {},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3122,

title = {An Integrated Platform for Educational Virtual Environments},

author = {Christos Bouras and Thrasivoulos Tsiatsos and Eleftheria Giannaka and Alexandros Panagopoulos and Maria Nani},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/81341159.pdf},

year  = {2006},

date = {2006-01-01},

urldate = {2006-01-01},

booktitle = {Web-Based Intelligent e - Learning Systems: Technologies and Applications},

pages = {291 - 320},

publisher = {IDEA Group Publishing},

chapter = {XV},

organization = {IDEA Group Publishing},

abstract = {In this chapter, we present the design and implementation of an integrated platform for Educational Virtual Environments. This platform aims to support an educational community, synchronous online courses in multi-user three-dimensional (3D) environments, and the creation and access of asynchronous courses through a learning content management system. In order to offer synchronous courses, we have implemented a system called EVE-II, which supports stable event sharing for multi-user 3D places, easy creation of multi-user 3D places, H.323-based voice- over IP services fully integrated in a 3D space, as well as many concurrent 3D multi-user spaces.},

keywords = {},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3123,

title = {Modeling Data Intensive Web Sites for Personalisation, Integrity and Performance},

author = {Christos Bouras and Agis Konidaris},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/7151905.pdf},

year  = {2003},

date = {2003-01-01},

urldate = {2003-01-01},

booktitle = {Information Modeling for Internet Applications},

pages = {259 - 276},

publisher = {IDEA Group Publishing},

chapter = {XII},

organization = {IDEA Group Publishing},

abstract = {This chapter presents a step-by-step approach to the design, implementation and management of a Data-Intensive Web Site (DIWS). The approach introduces five data formulation and manipulation graphs that are presented analytically. The core concept behind the modeling approach is that of “Web fragments,” that is an information decomposition technique that aids design, implementation and management of DIWS. We then present the steps that must be followed in order to “build” a DIWS based on Web fragments. Finally, we show how our approach can be used to ensure the basic DIWS user requirements of personalization, integrity and performance.},

keywords = {},

pubstate = {published},

tppubtype = {inbook}

}

@inbook{3124,

title = {Virtual Environments in Educational Networks},

author = {Christos Bouras and Agis Konidaris and Afroditi Sevasti},

url = {https://telematics.upatras.gr/wp-content/uploads/2024/01/6551356.pdf},

year  = {2000},

date = {2000-01-01},

urldate = {2000-01-01},

booktitle = {COMMUNICATIONS AND NETWORKING IN EDUCATION Learning in a Networked society, Edited by T. Downes and D. Watson},

pages = {195 - 203},

publisher = {Kluwer Academic Publishers},

organization = {Kluwer Academic Publishers},

abstract = {The field of Virtual Environments (VEs) is rapidly evolving into a new means of communication and accessing information, likely to overcome many existent technologies. However, being a new field makes the design and implementation of educational VEs an important aspect for scientific research in their educational potentials and the exploitation of existent technologies. New technologies in the field of VEs have appeared the establishment and combination of which, is yet to be investigated. This paper makes an effort to approach the issue of developing educational VEs introducing new aspects in the issues of interface, interaction with the user and functionality.},

keywords = {},

pubstate = {published},

tppubtype = {inbook}

}