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Ganatsas P.,Aristotle University of Thessaloniki | Spanos I.,Greek National Agricultural Research Foundation | Tsakaldimi M.,Aristotle University of Thessaloniki | Goudelis G.,Lamia Institute of Technology
Notulae Botanicae Horti Agrobotanici Cluj-Napoca | Year: 2012

Nine years after a wildfire, above- and below-ground morphology of Pinus brutia Ten. saplings and the microsite factors prevailing in understorey (unburned area) and postfire conditions (burned area) of the Forest Park of Thessaloniki were studied. Major stand characteristics (density, tree canopy cover, tree height, crown height, and diameter) were measured in the unburned area. Light and soil conditions as well as plant cover of woody species were recorded in both areas (burned and unburned). A random sample of pine saplings, of uniform age, was taken from both burned and unburned areas, and their above-ground (height, diameter, number and total length of branches, needle biomass) and below-ground morphological characteristics (taproot length, total length of coarse and fine roots, and number of coarse roots) were measured. Data analysis showed that above- and below-ground morphology of pine saplings was adversely affected in saplings grown in understorey conditions, compared to those grown in postfire conditions. P. brutia is a shade-intolerant tree species and thus the light conditions seem to be the critical factor affecting the growth of pine saplings. Light is not a limiting factor in the burned area compared to the understorey, where density of the tree canopy limits available light.


Zarikas V.,Lamia Institute of Technology | Loupis M.,Lamia Institute of Technology | Papanikolaou N.,Lamia Institute of Technology | Kyritsi C.,Lamia General Hospital
Safety Science | Year: 2013

This work presents results from a statistical survey regarding accidents in elevators and escalators in Greece, based on data concerning accidents from the last 12. years. A main objective is to explore and utilize frequencies and "correlations" among the involved factors, in order to weight and evaluate crucial mistakes and misguided actions. Results will help preventing similar accidents for the technical staff and the users, as well as designing and teaching a new culture and attitude from the users' side. Various statistical inferences were derived related to regulations for the installation, service and operation of elevators. An important finding is that 65% of the reported accidents involve qualified servicing and installation personnel or employees during their work, mainly associated with simultaneous violation of safety/health and internal electrical installations regulations. Other important outcomes concern associations between number of victims and categories of building types or of severity of accidents as well as between severity of accidents and categories of type of violated regulations or of elevator type. Furthermore, associations between severity of injury and categories of type of accident or of victims' age have been found. Proposals for the organization of the responsible authorities, data collection and prevention of similar serious accidents in the future are included. © 2013 Elsevier Ltd.


Soras G.,National and Kapodistrian University of Athens | Psaroudakis N.,National and Kapodistrian University of Athens | Mousdis G.A.,National Hellenic Research Foundation | Manos M.J.,University of Cyprus | And 12 more authors.
Chemical Physics | Year: 2010

The synthesis of a new nickel complex with an extended multi-sulfur dithiolene ligand Ni(etodddt)2 (etodddt = 4,5-(1,4-oxathiane-2,3- diyldithio)-1,3-dithiole) is described. It is characterized analytically and spectroscopically. The structure of the compound is determined by single crystal X-ray crystallography. Its redox potentials are determined using cyclic voltammetry and are compared with similar dithiolene complexes. Several other nickel derivatives are synthesized: bis(5,6-dihydro-1,4-dithiine-2,3-dithiole) nickel (Ni(dddt)2) and bis(6,7-dihydro-5H-[1,4] dithiepine-2,3- ddithiole) nickel (Ni(pddt)2). The non-linear optical response of the synthesized dithiolenes is measured in the visible (532 nm) and in the infrared (1064 nm) using the Z-scan technique with picosecond laser pulses. Both the refractive and absorptive parts of the third-order susceptibility χ(3) are determined and the second-order hyperpolarizabilities γ of the dithiolenes are determined and compared between them and with other reported in the literature data. The second hyperpolarizabilities of the synthesized metal derivatives are calculated by employing a series of computational approaches, involving density functional theory and a semi-empirical method. The first strong transition of the derivatives is attributed mainly to HOMO-LUMO pair connected with the intramolecular charge transfer π → π. Similar trends are observed between the experimental and the theoretical second hyperpolarizabilities, although the former are much larger due to resonance enhancement. The reported analysis demonstrates the complementarity of both experimental and theoretical results. It is shown that modest substitution of Ni(SCH)4, for example substitution of four H atoms by two S2C2H4 groups, leads to a very large increase of the second hyperpolarizability. © 2010 Elsevier B.V. All rights reserved.


Loupis M.I.,Lamia Institute of Technology | Kavadias C.,TELETEL SA | Papanikolaou N.P.,Lamia Institute of Technology
International Review on Computers and Software | Year: 2012

OPEN-SME introduces an Open Software Component Reuse, which collectively provides two processes and three tools. COMPARE (Component Repository and Search Engine) is one of the three tools, the one that allows SME software re-users to search and discover the assets (software artefacts, technical documents, test suites, metamodels) produced by the Domain Engineering Process. COMPARE features an advanced search engine that can be used for searching among the components, according to specific needs and selection criteria. Also, COMPARE supports the effective communication of structured information flows between the software re-users (asset consumers) and the reuse engineers (asset producers). These information flows allow re-users to place orders/requests and provide their feedback to the reuse engineers. © 2012 Praise Worthy Prize S.r.l. - All rights reserved.


Avramopoulos A.,National Hellenic Research Foundation | Avramopoulos A.,Lamia Institute of Technology | Serrano-Andres L.,University of Valencia | Li J.,Accelrys Inc. | Papadopoulos M.G.,National Hellenic Research Foundation
Journal of Chemical Theory and Computation | Year: 2010

The electronic ground state of H-Ng-Ng-F (Ng = Ar, Kr, Xe) has been studied theoretically by employing the ab initio complete active space valence bond (CASVB) and multi-state complete active space perturbation theory (MS-CASPT2) methods. Both levels of theory confirm the diradicaloid character (DC) of the HNg2F ground state, increasing in the order Ar > Kr > Xe. The very significant effect of the first and, even more, the second Xe atom on the (hyper)polarizabilities has been shown and interpreted. Thus, the present results demonstrate a mechanism for producing very large (hyper) polarizabilities. © 2010 American Chemical Society.


Filippou A.,University of Portsmouth | Karras D.A.,Chalkis Institute of Technology | Papazoglou P.M.,Lamia Institute of Technology | Papademetriou R.C.,University of Portsmouth
Communications in Computer and Information Science | Year: 2010

Coverage is one of the fundamental metrics used to quantify the quality of service (QoS) of sensor networks. In general, we use this term to measure the ability of the network to observe and react to the phenomena taking place in the area of interest of the network. In addition, coverage is associated with connectivity and energy consumption, both important aspects in the design process of a Wireless Sensor Network (WSN). On the other hand, simulating a WSN involves taking into account different software and hardware aspects. In this paper we attempt to present a simulation framework suitable for integrating coverage mechanisms in WSN emulation using a layered architecture and a fitting scheduling model. The suggested model is derived after a critical overview and presentation of the coverage strategies as well as the simulation approaches for WSN developed so far. The main advantage of the proposed framework is its capability to handle concurrent events occurring at WSN deployment and operation through the suitable layered scheduler integrated. © 2010 Springer-Verlag.


Papazoglou P.M.,Lamia Institute of Technology | Papazoglou P.M.,University of Portsmouth | Karras D.A.,Chalkis Institute of Technology | Papademetriou R.C.,University of Portsmouth
Telecommunication Systems | Year: 2013

The goal of this paper is to investigate the application of the Multi Agent technology in modeling and simulating large scale wireless communication systems. There are very few studies using the multi agent concept as an alternative approach for designing and simulating resource allocation in cellular systems and especially in large scale ones. Thus, a novel modeling methodology of wireless network services exploiting multi agent technology and investigating in depth critical agent issues is proposed in this paper. It is shown that the multi agent concept proves to be a suitable solution for modeling and implementing cellular network services simulation even in the case of large scale wireless networks. The whole investigation is divided in two phases: (a) multi agent modeling analysis and (b) multi agent model development for controlling network performance. Simulation results show the effectiveness of the proposed multi agent model when is applied in combination with the state of the art event scheduling mechanism. © 2011 Springer Science+Business Media, LLC.


Papazoglou P.M.,Lamia Institute of Technology | Papazoglou P.M.,University of Portsmouth | Karras D.A.,Chalkis Institute of Technology | Papademetriou R.C.,University of Portsmouth
1st International Conference on Future Generation Communication Technologies, FGCT 2012 | Year: 2012

The increasing number of cellular users and the demand for broadband mobile communications (3rd and 4th generation) raises the problem of bandwidth availability and the associated channel allocation strategies. Moreover, Quality of Service (QoS) is the challenge for such modern wireless multimedia telecommunications. This paper presents new algorithms for efficient bandwidth management of GSM cellular multimedia systems. Besides, it proposes a comprehensive simulation system for evaluating channel assignment schemes in QoS multimedia cellular systems incorporating their principles, entities and concepts involved. The proposed system is implemented in Java, in order to create an educational generic simulation environment with the future capability of internetworking. The system is designed with the goal to be efficient in simulating large scale generic cellular multimedia telecommunication systems. © 2012 IEEE.


Skwara B.,National Hellenic Research Foundation | Skwara B.,Wroclaw University of Technology | Loboda O.,National Hellenic Research Foundation | Loboda O.,Kyushu University | And 5 more authors.
AIP Conference Proceedings | Year: 2012

Recent studies of the linear and nonlinear electric properties of various fullerene-based subsystems are reviewed. The electric properties of derivatives of C60 fullerene with carbazole, benzothiazole, benzothiazole- triphenyloamine and free-base porphyrin substituents at different levels of theory are summarized. In addition, the electronic and vibrational electric properties of endohedral Sc2@C72 system are reported. © 2012 American Institute of Physics.

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