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Solomou G.,Hellenic Open University | Pierrakeas C.,Hellenic Open University | Pierrakeas C.,Technological Educational Institute TEI of Western Greece | Kameas A.,Hellenic Open University
Educational Technology and Society | Year: 2015

The ability to effectively administrate educational resources in terms of accessibility, reusability and interoperability lies in the adoption of an appropriate metadata schema, able of adequately describing them. A considerable number of different educational metadata schemas can be found in literature, with the IEEE LOM being the most widely known; however, it is often the case where it cannot fully accommodate the characteristics of several types of educational resources, that's why application profiles have been proposed. Each metadata standard and application profile usually comes with a different (either less or more semantically enriched) binding, thus allowing the retrieval and dissemination of resources with varying degrees of effectiveness. In this work, we propose an application profile of the IEEE LOM standard having special focus on distance learning material, while being generic enough so as to be applicable to any educational material and application. We then present an ontology model for this profile that aims to improve the potential discovery and retrieval of educational resources within intelligent e-learning environments. Source

Stanev D.,University of Patras | Moustakas K.,University of Patras | Gliatis J.,University of Patras | Koutsojannis C.,Technological Educational Institute TEI of Western Greece
Methods of Information in Medicine | Year: 2016

Introduction: This article is part of the Focus Theme of Methods of Information in Medicine on “Methodologies, Models and Algorithms for Patients Rehabilitation”. Objectives: The objective of the proposed approach is to develop a clinical decision support system (DSS) that will help clinicians optimally plan the ACL reconstruction procedure in a patient specific manner. Methods: A full body model is developed in this study with 23 degrees of freedom and 93 muscles. The knee ligaments are modeled as non-linear spring-damper systems and a tibiofemoral contact model was utilized. The parameters of the ligaments were calibrated based on an optimization criterion. Forward dynamics were utilized during simulation for predicting the model’s response to a given set of external forces, posture configuration and physiological parameters. Results: The proposed model is quantified using MRI scans and measurements of the well-known Lachman test, on several patients with a torn ACL. The clinical potential of the proposed framework is demonstrated in the context of flexion-extension, gait and jump actions. The clinician is able to modify and fine tune several parameters such as the number of bundles, insertion position on the tibia or femur and the resting length that correspond to the choices of the surgical procedure and study their effect on the biomechanical behavior of the knee. Conclusion: Computational knee models can be used to predict the effect of surgical decisions and to give insight on how different parameters can affect the stability of the knee. Special focus has to be given in proper calibration and experimental validation. © Schattauer 2016. Source

Papoulis D.,University of Patras | Komarneni S.,Pennsylvania State University | Panagiotaras D.,Technological Educational Institute TEI of Western Greece
Clay Minerals | Year: 2014

Trachyandesite rocks, occurring over an area of about 1 km2 in the southwest part of Limnos Island, Greece, are altered mainly to halloysite. The samples were collected and analysed by polarizing microscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and chemical analysis. The alteration of plagioclase to halloysite follows seven discrete stages that are described in detail. The geochemical evaluation of the data shows enrichment of the light REE (LREE) over heavy REE (HREE) as expressed by the (La/Yb)n ratio. The SLREE range from 206.44 to 272.30, while the sum of HREE varies from 11.01 to 26.26. The (La/Yb)n ratio ranges from 9.72 to 27.64. Fractionation among LREE expressed as (La/Sm)n and between middle REE (MREE) and HREE is shown as (Tb/Yb)n ratios. The most altered rocks close to the fault zone have high (Tb/Yb)n ratios and low (La/Sm)n and Eu/Eu ratios. Although mineralogy and clay mineral textures indicate hydrothermal genesis of halloysite, the geochemical data are not conclusive due to a secondary weathering effect. © 2014 The Mineralogical Society. Source

Kottou S.,National and Kapodistrian University of Athens | Nikolopoulos D.,Technological Educational Institute of Piraeus | Yannakopoulos P.H.,Technological Educational Institute of Piraeus | Petraki E.,Technological Educational Institute of Piraeus | And 2 more authors.
Physica Medica | Year: 2015

The main purpose of this work was to investigate the fluctuation of Greek indoor electromagnetic field (EMF) intensity values and identify peaks that might occur. The scientific interest is mainly focused on the bands of extremely low-frequency (ELF) magnetic fields and radiofrequency (RF) electric fields which have been suggested to be possibly carcinogenic to humans by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR).Electromagnetic radiation (EMR) measurements were performed in a variety of indoor dwellings, in Attica and in the islands of Zakynthos and Lesvos.A total number of 4540 measurements were taken in a wide frequency range (50 Hz-2100 MHz) of which 3301 in Attica, 963 in Lesvos and 276 in Zakynthos.Statistical analysis of the data revealed specific statistically significant differences between the mean values of the electric (ELF and RF) but not the magnetic (ELF) field strengths measured at different distances from the EMF source, as well as between some of the mean values of the RF electric field at different bands. Some statistically significant differences between mean electric field values at different geographic locations were also identified.As far as the RF electric field is concerned, the maximum values, in most cases, were below 0.5 V/m, however increased values above 1 V/m and up to 5.6 V/m were occasionally observed. The ELF magnetic field values were lower than 1 μT. It may be concluded that overall, the observed indoor EMF intensity values remained well below domestic and European established limits. © 2015 Associazione Italiana di Fisica Medica. Source

Papoulis D.,University of Patras | Komarneni S.,Pennsylvania State University | Panagiotaras D.,Technological Educational Institute TEI of Western Greece | Stathatos E.,Technological Educational Institute TEI of Western Greece | And 7 more authors.
Applied Catalysis B: Environmental | Year: 2014

For the first time two different nanoclay minerals were combined with nanophase anatase for the synthesis of three-phase nanocomposites with improved photocatalytic properties. The novel halloysite (H)+palygorskite (Pal)-TiO2 nanocomposites were prepared using palygorskite and halloysite from Greece. Three nanocomposites were synthesized using [Hal+Pal] to TiO2 mass ratios of [10+20]:70, [15+15]:70 and [20+10]:70, respectively by depositing anatase form of TiO2 on the clay surfaces using titanium isopropoxide as a precursor under hydrothermal treatment at 180°C. Phase composition, particle morphology and physical properties of these three-phase nanocomposites were characterized by XRD, ATR-FTIR, SEM, TEM, DR-UV-Vis, N2-adsorption/desorption isotherms. The photocatalytic activities of three-phase clay-titania nanocomposites in decomposing NOx gas and toluene vapor were determined. The three-phase clay-titania nanocomposites showed significantly higher photocatalytic activity in decomposing inorganic and organic pollutants compared to that of either palygorskite- or halloysite-TiO2 nanocomposites under both UV- and visible-light irradiation. These studies led to a new class of clay-based nanocomposite materials with advanced photocatalytic properties. © 2013 Elsevier B.V. Source

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