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Search Results: 1 - 10 of 2068 matches for " Askoxylakis Ioannis "
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Ubiquitous robust communications for emergency response using multi-operator heterogeneous networks
Fragkiadakis Alexandros,Askoxylakis Ioannis,Tragos Elias,Verikoukis Christos
EURASIP Journal on Wireless Communications and Networking , 2011,
Abstract: A number of disasters in various places of the planet have caused an extensive loss of lives, severe damages to properties and the environment, as well as a tremendous shock to the survivors. For relief and mitigation operations, emergency responders are immediately dispatched to the disaster areas. Ubiquitous and robust communications during the emergency response operations are of paramount importance. Nevertheless, various reports have highlighted that after many devastating events, the current technologies used, failed to support the mission critical communications, resulting in further loss of lives. Inefficiencies of the current communications used for emergency response include lack of technology inter-operability between different jurisdictions, and high vulnerability due to their centralized infrastructure. In this article, we propose a flexible network architecture that provides a common networking platform for heterogeneous multi-operator networks, for interoperation in case of emergencies. A wireless mesh network is the main part of the proposed architecture and this provides a back-up network in case of emergencies. We first describe the shortcomings and limitations of the current technologies, and then we address issues related to the applications and functionalities a future emergency response network should support. Furthermore, we describe the necessary requirements for a flexible, secure, robust, and QoS-aware emergency response multi-operator architecture, and then we suggest several schemes that can be adopted by our proposed architecture to meet those requirements. In addition, we suggest several methods for the re-tasking of communication means owned by independent individuals to provide support during emergencies. In order to investigate the feasibility of multimedia transmission over a wireless mesh network, we measured the performance of a video streaming application in a real wireless metropolitan multi-radio mesh network, showing that the mesh network can meet the requirements for high quality video transmissions.
A Family of Key Agreement Mechanisms for Mission Critical Communications for Secure Mobile Ad Hoc and Wireless Mesh Internetworking
Ioannis G. Askoxylakis,Theo Tryfonas,John May,Vasilios Siris
EURASIP Journal on Wireless Communications and Networking , 2011, DOI: 10.1155/2011/807684
Abstract:
Multimodal hypoxia imaging and intensity modulated radiation therapy for unresectable non-small-cell lung cancer: the HIL trial
Askoxylakis Vasileios,Dinkel Julien,Eichinger Monika,Stieltjes Bram
Radiation Oncology , 2012, DOI: 10.1186/1748-717x-7-157
Abstract: Background Radiotherapy, preferably combined with chemotherapy, is the treatment standard for locally advanced, unresectable non-small cell lung cancer (NSCLC). The tumor response to different therapy protocols is variable, with hypoxia known to be a major factor that negatively influences treatment effectiveness. Visualisation of tumor hypoxia prior to the use of modern radiation therapy strategies, such as intensity modulated radiation therapy (IMRT), might allow optimized dose applications to the target volume, leading to improvement of therapy outcome. 18 F-fluoromisonidazole dynamic positron emission tomography and computed tomography (18 F-FMISO dPET-CT) and functional magnetic resonance imaging (functional MRI) are attractive options for imaging tumor hypoxia. Methods/design The HIL trial is a single centre study combining multimodal hypoxia imaging with 18 F-FMISO dPET-CT and functional MRI, with intensity modulated radiation therapy (IMRT) in patients with inoperable stage III NSCLC. 15 patients will be recruited in the study. All patients undergo initial FDG PET-CT and serial 18 F-FMISO dPET-CT and functional MRI before treatment, at week 5 of radiotherapy and 6 weeks post treatment. Radiation therapy is performed as inversely planned IMRT based on 4D-CT. Discussion Primary objectives of the trial are to characterize the correlation of 18 F-FMISO dPET-CT and functional MRI for tumor hypoxia imaging in NSCLC and evaluate possible effects of radiation therapy on tumor re-oxygenation. Further objectives include the generation of data regarding the prognostic value of 18 F-FMISO dPET-CT and functional MRI for locoregional control, progression free survival and overall survival of NSCLC treated with IMRT, which will form the basis for larger clinical trials focusing on possible interactions between tumor oxygenation and radiotherapy outcome. Trial registration The ClinicalTrials.gov protocol ID is NCT01617980
A Family of Key Agreement Mechanisms for Mission Critical Communications for Secure Mobile Ad Hoc and Wireless Mesh Internetworking
Askoxylakis IoannisG,Tryfonas Theo,May John,Siris Vasilios
EURASIP Journal on Wireless Communications and Networking , 2011,
Abstract: Future wireless networks like mobile ad hoc networks and wireless mesh networks are expected to play important role in demanding communications such as mission critical communications. MANETs are ideal for emergency cases where the communication infrastructure has been completely destroyed and there is a need for quick set up of communications among the rescue/emergency workers. In such emergency scenarios wireless mesh networks may be employed in a later phase for providing advanced communications and services acting as a backbone network in the affected area. Internetworking of both types of future networks will provide a broad range of mission critical applications. While offering many advantages, such as flexibility, easy of deployment and low cost, MANETs and mesh networks face important security and resilience threats, especially for such demanding applications. We introduce a family of key agreement methods based on weak to strong authentication associated with several multiparty contributory key establishment methods. We examine the attributes of each key establishment method and how each method can be better applied in different scenarios. The proposed protocols support seamlessly both types of networks and consider system and application requirements such as efficient and secure internetworking, dynamicity of network topologies and support of thin clients.
Risk Management in On-Line Banking  [PDF]
Ioannis V. Koskosas
Intelligent Information Management (IIM) , 2011, DOI: 10.4236/iim.2011.34013
Abstract: In the context of goal setting, the more difficult the goal, given feedback on performance, the more focused is individuals’ attention and persistence to accomplish the goal and in turn, their performance is also improved. Similarly, when the goal is multi-complex and performance time constraint, the deployment of specific strategies maybe the best approach developed. In effect of the above, this investigation takes a socio-psychological and organizational perspective in setting information systems (IS) security goals. In doing so, three important issues of goal setting are identified, these are: trust, culture and risk communication. Since system security breaches are still on the rise, the performance of managing such online risks is not the one expected. The framework suggested in this paper aims to contribute to socio-psychological and organizational values by enhancing the performance of the IS risk management process with a focus on security risks.
Study the Critical Role of Admixtures in Cement Production: The Optimum State of Cassiterite (SnO2) Addition as a Natural Mineralizer-Oxide Influencing the Cement Properties  [PDF]
Ioannis Baziotis, Andreas Chandrinos
Advances in Chemical Engineering and Science (ACES) , 2011, DOI: 10.4236/aces.2011.14031
Abstract: In this work we evaluate the role of a natural mineralizer-oxide like cassiterite (SnO2) on the cement properties. In particular, we study the effect of different quantities of SnO2 with 0.5, 1.0, 1.5 and 2.0 wt% on burnability of industrial raw mix by free lime evaluation. We obtain four datasets, with successive increase of temperature at 1250℃, 1350℃, 1400℃ and 1450℃. We study the produced cassiterite-added clinker with X-ray diffraction (XRD), thermal analysis (DTA) and scanning electron microscopy (SEM). Though, we characterize the new phases formed and whether, adding excess SnO2 is promote forms of C3S, C2S influencing the final quality of cement.
Experimental Testing of Composite Panels Reinforced with Cotton Fibers  [PDF]
Ioannis G. Raftoyiannis
Open Journal of Composite Materials (OJCM) , 2012, DOI: 10.4236/ojcm.2012.22005
Abstract: A research project has been carried out at the National Technical University of Athens, Greece, to develop composite panels reinforced with cotton fibers. The primary aim of the project is to examine the mechanical properties of such panels for use in secondary structural members such as wall or door systems. The use of natural fibers such as cotton, flax or sisal fibers has the primary advantage of being eco-friendly, low cost and low weight compared to glass fibers on the expense of lower structural properties. This paper presents results from experimental work on composite plates made from polyester resin reinforced with cotton fibers, with special attention given to the effect of the fiber type on the structural properties of the plates. The results from this study showed that the structural performance of cotton fiber composites is satisfactory for structural parts with low requirements, such as wall panels or doors. The present results for cotton fiber composites are also compared to testing results from previous studies on composites with flax/sisal fibers.
Feature Extraction for Audio Classification of Gunshots Using the Hartley Transform  [PDF]
Ioannis Paraskevas, Maria Rangoussi
Open Journal of Acoustics (OJA) , 2012, DOI: 10.4236/oja.2012.23015
Abstract: In audio classification applications, features extracted from the frequency domain representation of signals are typically focused on the magnitude spectral content, while the phase spectral content is ignored. The conventional Fourier Phase Spectrum is a highly discontinuous function; thus, it is not appropriate for feature extraction for classification applications, where function continuity is required. In this work, the sources of phase spectral discontinuities are detected, categorized and compensated, resulting in a phase spectrum with significantly reduced discontinuities. The Hartley Phase Spectrum, introduced as an alternative to the conventional Fourier Phase Spectrum, encapsulates the phase content of the signal more efficiently compared with its Fourier counterpart because, among its other properties, it does not suffer from the phase ‘wrapping ambiguities’ introduced due to the inverse tangent function employed in the Fourier Phase Spectrum computation. In the proposed feature extraction method, statistical features extracted from the Hartley Phase Spectrum are combined with statistical features extracted from the magnitude related spectrum of the signals. The experimental results show that the classification score is higher in case the magnitude and the phase related features are combined, as compared with the case where only magnitude features are used.
Erythropoiesis Stimulating Agents (ESAs) in the Treatment of Cardio-Renal Syndrome Anaemia  [PDF]
Ioannis Koulouridis, Efstathios Koulouridis
Open Journal of Nephrology (OJNeph) , 2012, DOI: 10.4236/ojneph.2012.23004
Abstract: Coexistence of chronic kidney disease (CKD) and chronic heart failure (CHF) define a recently recognized clinical entity known as cardio-renal syndrome. Sufficient evidence suggests that the two pathological conditions share common pathogenic etiology which is not yet fully defined. Superimposed anaemia is a common finding among patients suffering from cardio-renal syndrome. The combination of CKD, CHF and anaemia increase the probability of death by 6 times compared to normal individuals. Early attempts to restore anaemia either by iron supplementation, erythropoiesis stimulating agents (ESAs) or combination of the two have reported to improve quality of life, morbidity and mortality especially among patients treated by cardiologists. Recent publications of well controlled epidemiological studies failed to prove convincing beneficial effect of the above mentioned therapy moreover skepticism has raised concerning the safety of restoring anaemia among patients with cardio-renal syndrome as well as used medications. There are still unresolved problems concerning the definition of anaemia, by means of hemoglobin level among these patients, the target hemoglobin level and the therapeutic regimen of ESAs administration and iron supplementation. We need much more evidence in order to define an effective and safe treatment strategy correcting anaemia among patients with cardio-renal syndrome.
Third-Order Corrections and Mass-Shedding Limit of Rotating Neutron Stars Computed By a Complex-Plane Strategy  [PDF]
Ioannis Sfaelos, Vassilis Geroyannis
International Journal of Astronomy and Astrophysics (IJAA) , 2012, DOI: 10.4236/ijaa.2012.24027
Abstract: We implement the so-called “complex-plane strategy” for computing general-relativistic polytropic models of uniformly rotating neutron stars. This method manages the problem by performing all numerical integrations, required within the framework of Hartle’s perturbation method, in the complex plane. We give emphasis on computing corrections up to third order in the angular velocity, and the mass-shedding limit. We also compute the angular momentum, moment of inertia, rotational kinetic energy, and gravitational potential energy of the models considered.
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