Papers by Christos Kaklamanis
Springer eBooks, 2012
support tools and environments.-performance prediction and evaluation.-scheduling and load balanc... more support tools and environments.-performance prediction and evaluation.-scheduling and load balancing.-high-performance architectures and compilers.-parallel and distributed data management.-grid, cluster and cloud computing.-peer to peer computing.-distributed systems and algorithms.-parallel and distributed programming.-parallel numerical algorithms.-multicore and manycore programming.-theory and algorithms for parallel computation.-high performance network and communication.-mobile and ubiquitous computing.-high performance and scientific applications.-GPU and accelerators computing.
Springer eBooks, Nov 16, 2007
In this paper we give a short overview of the IST FET Integrated Project FP6-015964 AEOLUS “Algor... more In this paper we give a short overview of the IST FET Integrated Project FP6-015964 AEOLUS “Algorithmic Principles for Building Efficient Overlay Computers” which is funded by the European Union as part of the Proactive Initiative on Global Computing. We present the motivation and our long-term vision behind it and its objectives. We also give a short description of the research workplan and current activities.
Springer eBooks, 2001
We study the problem of allocating optical bandwidth to sets of communication requests in all-opt... more We study the problem of allocating optical bandwidth to sets of communication requests in all-optical networks that utilize Wavelength Division Multiplexing (WDM). WDM technology establishes communication between pairs of network nodes by establishing transmitter-receiver paths and assigning wavelengths to each path so that no two paths going through the same fiber link use the same wavelength. Optical bandwidth is the number of distinct wavelengths. Since state-of-the-art technology allows for a limited number of wavelengths, the engineering problem to be solved is to establish communication between pairs of nodes so that the total number of wavelengths used is minimized; this is known as the wavelength routing problem.In this paper we survey recent advances in bandwidth allocation in tree-shaped WDM all-optical networks. We present hardness results and lower bounds for the general problem and the special case of symmetric communication. We also survey various techniques that have been developed recently, and explain how they can be used to attack the problem. First, we give the main ideas of deterministic greedy algorithms and study their limitations. Then, we show how to use various ways and models of wavelength conversion in order to achieve almost optimal bandwidth utilization. Finally, we show that randomization can help to improve the deterministic upper bounds.
Journal of Parallel and Distributed Computing, Aug 1, 2018
Theory of computing systems, Apr 8, 2015
EDULEARN11 Proceedings, Jul 1, 2022
e-me is a social, collaborative, and extendable cloud-based digital educational platform for stud... more e-me is a social, collaborative, and extendable cloud-based digital educational platform for students and teachers, designed to support formal, non-formal, or informal learning experiences. e-me provides each member with a safe personal digital workspace to connect, communicate, collaborate, set up public or private collaborative learn-spaces, store and exchange files, along with a suite of tools (apps) to create and share learning resources, develop and monitor assignments, create e-portfolios, etc. We introduced e-me in 2015, as a Personal Learning Environment (PLE) we designed and developed for the Greek Ministry of Education (MoE) to operate as an educational platform for all students and teachers in Greece. Since then, e-me has greatly evolved and expanded with new functionalities, being today a mature and innovative educational platform supporting modern pedagogy, with three installations, and more than 650,000 registered users. In 2020, e-me was offered by the Greek MoE to all students and teachers to support emergency remote teaching in primary and secondary education in response to the Covid-19 pandemic-crisis. The paper presents the extended and updated e-me of today (v3.0), as well as our experiences from its nationwide official use in pandemic times.
Education and New Developments 2022 – Volume 2
2016 IEEE Intl Conference on Computational Science and Engineering (CSE) and IEEE Intl Conference on Embedded and Ubiquitous Computing (EUC) and 15th Intl Symposium on Distributed Computing and Applications for Business Engineering (DCABES), 2016
This work presents a case study for the integration of two web-based systems, the "Kaltura&q... more This work presents a case study for the integration of two web-based systems, the "Kaltura" video platform and the "Photodentro Video" digital repository. The integration is based on the Open Archives Initiative Protocol for Metadata Harvesting and an associated automation, transformation, and push/pull notification strategy. Kaltura is a video management platform, which allows publishers and content producers to distribute, manage, and monetize their videos and other rich-media content. Photodentro Video is the Greek Educational Video Repository for primary and secondary education, based on the DSpace open source digital repository management system. The architecture and the orchestrated workflow of the integration of Kaltura and Photodentro Video are presented, with emphasis on the addressed challenges. Furthermore, the technologies for scaling up the video service provided by Kaltura to a massive number of end-users are reviewed and discussed along with the proposed solution. Finally, the performance of the overall integrated platform is evaluated.
“e-me” is the Hellenic Digital Educational Platform to be provided by the Ministry of Education t... more “e-me” is the Hellenic Digital Educational Platform to be provided by the Ministry of Education to the Greek K-12 community that includes more than 1,100,000 pupils and 120,000 teachers. It is currently under development by CTI Diophantus. e-me implements a social learning environment with a modern and intuitive user interface, where certified members of the primary and secondary education community can safely share content, connect and collaborate with peers, publish their work, use a large number of embedded applications, and interact with a wealth of digital learning resources. The article introduces the core concepts of e-me, the main goal and objectives for its implementation, and highlights the key elements of its software design and development.
This paper presents Photodentro LOR, the Greek National Learning Object Repository (LOR) for prim... more This paper presents Photodentro LOR, the Greek National Learning Object Repository (LOR) for primary and secondary education. Photodentro LOR hosts open learning objects: small, semantically and functionally autonomous, reusable, open educational resources, tagged with educational metadata. It is targeted to teachers and pupils and it constitutes a core part of the Greek Ministry of Education digital infrastructure for educational content for schools. The paper also discusses issues to be taken into account when designing a National Learning Object Repository for schools, and provides an overview of the Photodentro LOR design and implementation, including semantic interoperability and metadata issues, technical decisions, and workflows for content population. The big picture of the infrastructure that includes the Photodentro National Educational Content Aggregator is also given.
Journal of Parallel and Distributed Computing, 2018
ICERI2016 Proceedings, 2016
The "Photodentro SaaS" initiative drives the expansion of the Photodentro ecosystem of Open Educa... more The "Photodentro SaaS" initiative drives the expansion of the Photodentro ecosystem of Open Educational Resource (OER) repositories. The initiative is based on the "Software as a Service" model (SaaS), allowing for all interested organisations to implement a Photodentro repository to manage, describe, and publish their digital artefacts. The benefits are twofold: (i) the new content provider gains exclusive access to a standards-based digital repository, integrating the best practices and workflows specifically designed to meet the needs of OER for K12 education; (ii) being part of the Photodentro ecosystem, all resources of the new repository are readily available and profit of high visibility through the web portal of the Photodentro Greek National Educational Content Aggregator.
Lecture Notes in Computer Science, 2005
Partitioned Optimal Passive Stars network, POPS(d, g), is an optical interconnection network of N... more Partitioned Optimal Passive Stars network, POPS(d, g), is an optical interconnection network of N processors (N = dg) which uses g 2 optical passive star couplers. The processors of this network are partitioned into g groups of d processors each and the g 2 couplers are used for connecting each group with each of the groups, including itself. In this paper, we present an optimal embedding of the hypercube on this network for all combinations of values of d and g. Specifically, we show how to optimally simulate the most common hypercube communication pattern where each hypercube node sends a packet along the same dimension. Optimal simulation of this communication on the POPS(d, g) network has already been presented for d ≤ g in the literature, but for the case d > g, the optimality remained an open problem. Now, we show that an optimal simulation is feasible in this case too.
Theory of Computing Systems, 2015
Parallel Algorithms and Applications, 2004
One of the most important features in image analysis and understanding is shape. Mathematical mor... more One of the most important features in image analysis and understanding is shape. Mathematical morphology is the image processing branch that deals with shape analysis. The definition of all morphological transformations is based on two primitive operations, i.e. dilation and erosion. Since many applications require the solution of morphological problems in real time, researching time efficient algorithms for these two
Lecture Notes in Computer Science, 2002
Algorithms – ESA 2005, 2005
Proceedings 14th International Parallel and Distributed Processing Symposium. IPDPS 2000
SPIE Proceedings, 1999
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Papers by Christos Kaklamanis