Psachná, Greece
Psachná, Greece

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Vartholomeos P.,Omega Technology | Katevas N.,TEI of Sterea Ellada | Sarakis L.,TEI of Sterea Ellada
2016 International Conference on Telecommunications and Multimedia, TEMU 2016 | Year: 2016

During the last decade there is an ever increasing interest for human-robot and, in general, user-machine interaction schemes of low-complexity and high-accuracy. In this context, intuitive and user-friendly interfaces based on hand gestures and movements are particular important for everyday users (especially older ones) of service robotics applications. In this paper, we explore the use of Inertial Measurement Unit (IMU) in a versatile movement sensing device that can be used by an elderly person to tele-manipulate a robot arm that helps him/her to complete bathing tasks. We present tele-manipulation system requirements taking into account the required accuracy in motion tracking and the need to address the limited physical abilities of the targeted user. We also discuss the integration of the tele-manipulation component into the envisaged service robotics environment and present an approach for its realization. Preliminary results assessing the performance of the proposed motion tracking system are also presented. © 2016 IEEE.

Fotiadis G.,TEI of Sterea Ellada | Vrahnakis M.,TEI of Thessaly | Kazoglou Y.,Municipality of Prespa | Tsiripidis I.,Aristotle University of Thessaloniki
Hacquetia | Year: 2014

A recently completed project on the Natura 2000 sites of Prespa National Park revealed that the area hosts 49 habitat types according to the EU classification, of which eight have a narrowly restricted distribution in Greece. The priority habitat type "6260 Pannonic sand steppes" is reported here for the first time for Greece. The new locality represents its southernmost occurrence on the Balkan Peninsula. The aim of this paper therefore is to describe the Greek stands of this habitat type, investigate the factors affecting its occurrence and discuss the associated conservation issues. This is based on a total of 87 releves sampled for this study and 8 additional releves from the literature. The releves were classified by applying TWINSPAN and ordinated using Detrended Correspondence Analysis (DCA). Six vegetation units could be distinguished. One of these corresponds to the habitat type 6260 and was found exclusively on inland sand dunes. Syntaxonomically, we assigned this unit to the alliance Sileno conicae-Cerastion semidecandri s.l. of the class Koelerio-Corynephoretea. Its occurrence in the study area seems to be determined by climatic factors, as well as by the sandy substrate, while anthropogenic disturbances such as grazing also appear to be beneficial to some degree. Apart from the Koelerio-Corynephoretea, another five grassland classes were distinguished in the national park, namely the Thero-Brachypodietea, Stellarietea mediae, Festuco-Brometea, Daphno-Festucetea and Juncetea trifidi.

Ktena A.,TEI of Sterea Ellada | Hristoforou E.,National Technical University of Athens | Gerhardt G.J.L.,University of Caxias do Sul | Missell F.P.,University of Caxias do Sul | And 3 more authors.
Physica B: Condensed Matter | Year: 2014

Magnetic Barkhausen noise (mBN) is known to be related to magnetization reversal mechanisms and the underlying microstructure in magnetic materials. However, the quantitative evaluation of the material properties is hindered by the stochastic nature of the method combined with the lack of standardization. In this paper, the results of interlaboratory tests on the same series of samples are presented. Electrical steel samples have been prepared with controlled grain size (11-148 μm) and strain (0-29%) and have been characterized using the mBN technique as developed in three different laboratories. In spite of the different methodologies used, mBN is found to increase with strain and decrease with decreasing grain size, in all cases. Of special interest is the variation of the double-peaked BN envelope with the grain size, with one peak occurring in positive and the other in negative fields. The significance of the methodology used in the correct interpretation of the results for a given material is discussed. © 2013 Elsevier B.V.

Vrahnakis M.,TEI of Thessaly | Fotiadis G.,TEI of Sterea Ellada | Kazoglou Y.,Lemos
Journal of Environmental Protection and Ecology | Year: 2015

The endemic Prespa trout (Salmo peristericus Karaman 1938) is a flagship species for the Prespa National Park. The aim of the research was to present environmental impacts of works done to improve a forest road (in January-February 2010) on the trout habitats in the Siroka stream which flows parallel to the road. The assessment was based on the use of the QBR (Qualitat del Bosc de Ribera) and RMP (Riparian Macrophyte Protocol) protocols. Results are presented in a comparative manner since the same protocols were used five months before the road improvement (September 2009). It was found that the irrational widening of the road and the volume of excavated soils deposited within the riparian zone, especially in the sampling stations, led to significant deterioration of the abiotic characteristics of the stream and the habitat quality of the Prespa trout.

Ktena A.,TEI of Sterea Ellada | Mele E.,SAIKON | Tsalkitzi E.,SAIKON | Manasis C.,TEI of Sterea Ellada | And 5 more authors.
Proceedings of the European Conference on Games-based Learning | Year: 2015

Over the last two decades we are witnessing an accelerating paradigm shift in electricity grids and markets. The power grid, enabled by technologies such as renewable energy sources (RES), microgeneration, telemetering and telecontrol, is moving towards demand side management, under the pressure for energy saving and low carbon economy on the one hand and electricity market deregulation on the other. Demand side management requires the user to be an active agent interacting in real time with the grid and the markets rather than a passive consumer whose only interaction with the gird is paying the bill and reporting faults. Under this light, the majority of electricity users could be considered as technologically illiterate, lacking fundamental knowledge and skills, which hinders the uptake of technologies and distorts related policies. Smartege has been designed and developed as a gamified application to educate electricity users, regardless of their profile, and modify the way they perceive their relationship with the electricity grid. To that end, persuasive modeling, gamification and cognitive learning have been used in a synergistic way. The expected learning outcomes of the user are to know, understand, apply basics of electricity use and generation towards efficient energy management as well as to analyse, evaluate and create energy efficient scenarios. Existing applications, such as Electric Box, Energy Quest, Ollie's World, Electrocity, Power Matrix, Energy Ville, et. al., focus mostly on children's and teenagers' conditioning towards a more overall 'green' attitude; address only one type of user's interaction with the electricity grid; or, are designed to promote commercial products and processes. Smartege on the other hand is a game of roles, simulation, strategy, quizzes and learning. The game uses an engaging graphical user interface that emulates the basic daily functions and activities of an electricity user in a house and an office building, in real time. Using gamification mechanics, the user is guided to understand the energy profile of appliances and equipment operating in the virtual buildings with respect to user-defined set points, to evaluate the effect of his/her actions and habits on them, to analyse the costs and benefits associated with energy upgrading or saving tactics. The user is gradually allowed to 'produce' electricity in the quest for net Zero Energy Buildings. The user's knowledge base is improving through various content forms, such as tips, information, reading material, quizzes, exercises. The user is triggered at appropriate times with engaging messages and is motivated by counters, reputation points, leaderboards and badges. Special emphasis is given in the game's social dimension, employing social media, promoting user's interaction and information exchange for gaining points. Finally, at advanced levels, by purchasing appropriate hardware, the user can emulate, monitor and control the electricity use and production of a real installation.

Papaefstathiou I.,Synelixis Solutions Ltd | Chrysos G.,Technical University of Crete | Sarakis L.,TEI of Sterea Ellada
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

This paper present a recently started multi-national project which will provide an innovative comprehensible, ultra-Fast, security-Aware CPS Simulator (called COSSIM) that will seamlessly simulate both the networking and the processing parts of the Cyber Physical Systems (CPS) significantly faster and more accurate than any existing solution. In order to achieve that COSSIM will develop a novel simulator framework based on a processing simulation subsystem (i.e. a “full-system simulator”) which will be integrated with a novel network simulator. Furthermore, innovative power consumption and security measurement models will be developed and incorporated to the end framework. On top of that, COSSIM will also address another critical aspect of an accurate CPS simulation environment: the performance as measured in required simulation time. COSSIM will create a framework that is orders of magnitude faster, while also being more accurate and reporting more CPS aspects, than existing solutions, by applying hardware acceleration through the use of field programmable gate arrays (FPGAs), which have been proven extremely efficient in relevant tasks. This paper presents the high-level architecture of the end-system as well the most innovative aspects of it that will allow it to be the fastest and most accurate such simulator, while it does not cover the security aspects of this novel system. © Springer International Publishing Switzerland 2015.

Karagiannis V.,TEI of Sterea Ellada | Ktena A.,TEI of Sterea Ellada | Manasis C.,TEI of Sterea Ellada | Ladoukakis O.,TEI of Sterea Ellada | And 3 more authors.
MATEC Web of Conferences | Year: 2016

A homemade electrodeposition device is presented, capable of depositing thin films of variable stoichiometry on cylindrical substrates offering control of electrolysis current, temperature and stirring velocity. The device design eliminates gravitational settling and uses a novel technique for fluid agitation in order to optimize deposition uniformity. The device surpasses traditional burato-style design in terms of gravitational settling of the solution and stirring homogeneity, as well as in terms of coating quality, i.e. cracking and blackened areas. © Owned by the authors, published by EDP Sciences, 2016.

Ktena A.,TEI of Sterea Ellada
Physica B: Condensed Matter | Year: 2016

Residual stresses in magnetic materials, whether the result of processing or intentional loading, leave their footprint on macroscopic data, such hysteresis loops and differential permeability measurements. A Preisach-type vector model is used to reproduce the phenomenology observed based on assumptions deduced from the data: internal stresses lead to smaller and misaligned grains, hence increased domain wall pinning and angular dispersion of local easy axes, favouring rotation as a magnetization reversal mechanism; misaligned grains contribute to magnetostatic fields opposing the direction of the applied field. The model is using a vector operator which accounts for both reversible and irreversible processes; the Preisach concept for interactions for the role of stress related demagnetizing fields; and a characteristic probability density function which is constructed as a weighed sum of constituent functions: the material is modeled as consisting of various subsystems, e.g. reversal mechanisms or areas subject to strong/weak long range interactions and each subsystem is represented by a constituent probability density function. Our assumptions are validated since the model reproduces the hysteresis loops and differential permeability curves observed experimentally and calculations involving rotating inputs at various residual stress levels are consistent and in agreement with experimental evidence. © 2016 Elsevier B.V.

Sarakis L.,TEI of Sterea Ellada | Leligou H.C.,TEI of Sterea Ellada | Karkazis P.,Technical University of Crete | Velivassaki T.-H.,TEI of Sterea Ellada | Zahariadis T.,TEI of Sterea Ellada
2014 International Conference on Telecommunications and Multimedia, TEMU 2014 | Year: 2014

We evaluate a routing metric, called TXPFI, which captures the expected number of frame transmissions needed for successful delivery of data in Wireless Sensor Networks (WSNs) featuring non-fully cooperative nodes and unreliable links. The study, which addresses the exploitation of the TXPFI in routing protocols of distance-vector type, assesses the impact of different network settings on the performance of the metric, compares the TXPFI with a number of routing metrics derived from the composition of primary metrics commonly used in routing protocols for WSNs, and evaluates the distribution of the transmission load to network nodes. The simulation results show that the TXPFI exhibits consistent behavior for different network parameters, outperforms the other composite metrics included in the study in terms of the overall number of transmitted frames and performs reasonably well regarding the maximum transmission load placed on the network nodes. © 2014 IEEE.

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