T. Doukoglou

ADSL2: a sequel better than the original?

Communications Engineer, 2004

ABSTRACT Not Available

Subjective Video Codec Evaluation for Streaming Services up to 1 Mbps

Lecture Notes in Computer Science, 2004

ABSTRACT Recent research has established that we can offer dvd-quality video streaming services t... more ABSTRACT Recent research has established that we can offer dvd-quality video streaming services to customers with broadband network access using MPEG1 and MPEG2 coding schemes at bit-rates greater than 1.5Mbps, achieving an optimal balance between bandwidth and quality around 3Mbps. New video codecs have evolved and matured which can reduce the necessary streaming bandwidth without adversely affecting quality to an unacceptable degree [1]. As these codecs are based on lossy coding algorithms, it is essential to gain an understanding of the subjective quality offered, as perceived by the end user of multimedia services. This understanding will not be built on a mathematic analysis which would reveal the actual quality of each encoding, but will rather use a statistical method to ascertain the perceived quality from the user point of view, which will be the guideline for creating and offering multimedia network services.

Service Differentiation and Traffic Engineering in IP over WDM Networks

IEEE Communications Magazine, 2008

Wavelength-division multiplexing (WDM) tech-nology was originally developed and emerged as a solu... more

ADSL2 against SHDSL for symmetric broadband access networking

Electronics Letters, 2004

Increasing demand for more upstream bandwidth as well as better symmetry in broadband access tech... more Increasing demand for more upstream bandwidth as well as better symmetry in broadband access technologies (dictated partly by the ever increasing popularity of applications such as peer-to-peer networking) turns the attention of network access providers to the already established SHDSL and the emerging ADSL2 (Annex J=M) technologies. This report evaluates and compares these two alternatives with regard to their respective performance in relation to varying copper loop length. This comparison is based on actual measurements of bit rates, line attenuation and SNR levels for both technologies.

Download

On statistical power grid observability under communication constraints (invited paper)

IET Smart Grid, 2018

On statistical power grid observability under communication constraints (invited paper). IET Smar... more

Download

Integration of digital angiography and gamma-camera diagnostic modalities to a generalized hospital information system

Studies in Health Technology and Informatics, 1997

Within the framework of the NIKA project for the development of a "Generalized System for Pr... more Within the framework of the NIKA project for the development of a "Generalized System for Processing and Management of Medical Images", we have integrated a Digital Subtraction Angiography (DSA) station and a gamma-camera diagnostic modality to the newly developed generalized hospital-wide information system. The integration consists of acquiring, digitizing, converting and filing the information from the above diagnostic modalities to the hospital's Picture Archiving and Communication System (PACS). The PACS, which is installed in the Onasio Cardiosurgery Centre of Athens, Greece, is responsible for archival, cataloging, retrieval and viewing of the large volume of patient examination data accumulated during his/her stay in the Centre. The ultimate goal is for all patient data, from all different examinations, to be viewed on dedicated client workstations. Information from different modalities can then be simultaneously presented to the attending physician, for a comp...

Integration of digital angiography and gamma-camera diagnostic modalities to a generalized hospital information system

Within the framework of the NIKA project for the development of a "Generalized System for Pr... more Within the framework of the NIKA project for the development of a "Generalized System for Processing and Management of Medical Images", we have integrated a Digital Subtraction Angiography (DSA) station and a gamma-camera diagnostic modality to the newly developed generalized hospital-wide information system. The integration consists of acquiring, digitizing, converting and filing the information from the above diagnostic modalities to the hospital's Picture Archiving and Communication System (PACS). The PACS, which is installed in the Onasio Cardiosurgery Centre of Athens, Greece, is responsible for archival, cataloging, retrieval and viewing of the large volume of patient examination data accumulated during his/her stay in the Centre. The ultimate goal is for all patient data, from all different examinations, to be viewed on dedicated client workstations. Information from different modalities can then be simultaneously presented to the attending physician, for a comp...

Developing Measures and Standards for the European Electronic Signatures Market

Cases on Managing E-Services, 2009

The European Authorities have promoted a specific and innovative framework for the use of electro... more The European Authorities have promoted a specific and innovative framework for the use of electronic signatures, allowing the free flow of electronic signature-related products and services cross borders, and ensuring a basic legal recognition of such facilities. The core aim was to promote the emergence of the internal market for certification products, mainly intending to satisfy various requirements for the proper use and immediate “adoption” of electronic signature applications related to e-government and personal e-banking services. Thus, a number of technical, procedural, and quality standards for electronic signature products and solutions have been developed, all conforming to the requirements imposed by the EU regulation and the relevant market needs. In the present work, we examine the role of standardization activities for the promotion of several needs of an “open” European market based on the effective usage of e-signatures, and being able to affect a great variety of t...

Download

Characterization and use of a novel optical position sensor for microposition control of a linear motor

Review of Scientific Instruments, 1993

Download

Spherical-coordinate scanning confocal laser microscope

Optical Engineering, 1995

Download

E-Learning Applications through Space Observations

Encyclopedia of …, 2009

In the context of the present work, we discuss several fundamental issues originating from the wo... more In the context of the present work, we discuss several fundamental issues originating from the work already performed in the scope of the Discovery Space (DSpace) Research Project, founded by the European eTEN Work Program. The Project has been awarded as the “Project of the Month - November, 2006” and the “second best European research activity” in the scope of e-learning thematic activities (http://www. discoveryspace.net/). The prime purpose of the work was the development of a virtual science center, able to integrate robotic telescopes from all over the world into one “virtual observatory” through a proper Web-based interface, to provide an automated scheduling of the telescopes to end-users (i.e., students, teachers, and researchers) and access to a library of data and resources for lifelong learners. Potential users can benefit from professional-quality data from their local sites, using modern broadband (Internet-based) facilities (European Commission, 2002). Following the echo from the market request for more cost-effective and compelling applications to be delivered over the currently-launched broadband networks supporting the expansion of the global information society (The European Survey of National Priorities in Astronomy, 2004), the relevant service application aimed to take advantage of the convenience of the high-speed Internet access to involve its various users (originating from distinct thematic categories) in extended episodes of playful learning. The basic issue was the creation and presentation, to the market, of an entirely interoperable worldwide service, able to support options for further enhancement of e-learning facilities for teachers, students, researchers, and other practitioners. The approach has been considered the existing Internet-based facilities as the basis to “transform the today’s classroom to a research laboratory” and to develop further the European e-learning market (Chochliouros &amp; Spiliopoulou, 2004; Danish Technological Institute, 2004).

$Research paper thumbnail of Volumetric image distortion due to refractive index mismatch in 3D confocal scanning laser microscopy$

Volumetric image distortion due to refractive index mismatch in 3D confocal scanning laser microscopy

In the application of 3D-volume reconstruction from 2D image slices acquired by a confocal scanni... more In the application of 3D-volume reconstruction from 2D image slices acquired by a confocal scanning laser microscope errors arise due to refractive index mismatch. This paper presents a brief theoretical analysis of this error that can lead to miscalculating a specimen's 3D geometry. A comparison between the error analysis and experimental measurements is also provided

Download

ADSL2+ Technology

Encyclopedia of Internet Technologies and Applications, 2000

Implementation, management and service provisioning of an experimental IP-over-WDM overlay network

SympoTIC '04. Joint 1st Workshop on Mobile Future & Symposium on Trends In Communications (IEEE Cat. No.04EX877), 2004

ABSTRACT This paper describes the experimental IP over WDM overlay network which was implemented ... more ABSTRACT This paper describes the experimental IP over WDM overlay network which was implemented in the Athens Metropolitan area using the installed optical MAN infrastructure of the Hellenic Telecommunications Organization (OTE). Its main purpose was to serve as a real-life test-bed for evaluating and demonstrating the feasibility of providing next generation IP services over an ultra high-speed core network. It was also used to examine the manageability and resilience of such a network as well as to investigate the interoperability of the overlay optical network with legacy core and access technologies, including ATM, POS and xDSL.

ADSL2+ Technology

Encyclopedia of Internet Technologies and Applications, 2008

ADSL2+ Technology (9781591409939): D. Kagklis, S. Androulidakis, G. Patikis, T. Doukoglou: Book C... more

Image coding and compression of confocal microscope volumetric 3D images

Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 1997

ABSTRACT Confocal microscopy allows for 3D volumetric image acquisition and in many cases simulta... more ABSTRACT Confocal microscopy allows for 3D volumetric image acquisition and in many cases simultaneous 3D multi-mode image acquisition, where each image voxel encompasses multiple values representing the output from the different imaging (contrast) modes (i.e. intensity, phase, polarisation etc.) of the confocal microscope. The amount of the acquired data is therefore increased significantly, making essential the employment of data reduction techniques. In this paper the authors present techniques and preliminary results for 3D volumetric image compression that allow for reduced image compression storage requirements, improved transmission and more efficient browsing through large amounts of stored data

Integration of digital angiography and gamma-camera diagnostic modalities to a generalized hospital information system

Studies in health technology and informatics, 1997

Within the framework of the NIKA project for the development of a "Generalized System for Pr... more Within the framework of the NIKA project for the development of a "Generalized System for Processing and Management of Medical Images", we have integrated a Digital Subtraction Angiography (DSA) station and a gamma-camera diagnostic modality to the newly developed generalized hospital-wide information system. The integration consists of acquiring, digitizing, converting and filing the information from the above diagnostic modalities to the hospital's Picture Archiving and Communication System (PACS). The PACS, which is installed in the Onasio Cardiosurgery Centre of Athens, Greece, is responsible for archival, cataloging, retrieval and viewing of the large volume of patient examination data accumulated during his/her stay in the Centre. The ultimate goal is for all patient data, from all different examinations, to be viewed on dedicated client workstations. Information from different modalities can then be simultaneously presented to the attending physician, for a comp...

Provisioning of IP multimedia services with guaranteed QoS to residential customers over heterogeneous networks

International Journal of Internet Protocol Technology, 2006

As content providers turn their attention towards the residential market, offering triple-play se... more As content providers turn their attention towards the residential market, offering triple-play services over the expanding broadband access network, it is necessary to guarantee appropriate levels of quality. However, provisioning such services over a heterogeneous network is facilitated by adopting a common 'language' of defining quality policies. In this paper, we attempt to provision multimedia-rich services over such a network with guaranteed quality, based on an 'overlay' IP-based approach. This 'all-IP' approach will allow us to influence the treatment of service traffic along the network path from the content provider's network up to the home network, regardless of underlying technologies.

Download

Bonding Techniques for Symmetric Services over ADSL and ADSL2/2+

EUROCON 2005 - The International Conference on "Computer as a Tool", 2005

ABSTRACT Newer IP services are bandwidth-intense and/or symmetric in nature. Bonding multiple ADS... more ABSTRACT Newer IP services are bandwidth-intense and/or symmetric in nature. Bonding multiple ADSL links is an appealing high-speed low-cost solution for more bandwidth, in anticipation of ADSL2/2+ deployments, while upstream performance defines the symmetric link capacity. We examine techniques applicable to ADSL and ADSL2/2+, outlining the optimal solution for aggregating N access links

Nonparametric two-dimensional point spread function estimation for biomedical imaging

Medical & Biological Engineering & Computing, 1993

Download

Uploads

Papers by T. Doukoglou

Log In