Showing papers by "Hellenic Military Academy published in 2016"

Investigating the feasibility of geo-Tagged photographs as sources of land cover input data

Abstract: Geo-tagged photographs are used increasingly as a source of Volunteered Geographic Information (VGI), which could potentially be used for land use and land cover applications. The purpose of this paper is to analyze the feasibility of using this source of spatial information for three use cases related to land cover: Calibration, validation and verification. We first provide an inventory of the metadata that are collected with geo-tagged photographs and then consider what elements would be essential, desirable, or unnecessary for the aforementioned use cases. Geo-tagged photographs were then extracted from Flickr, Panoramio and Geograph for an area of London, UK, and classified based on their usefulness for land cover mapping including an analysis of the accompanying metadata. Finally, we discuss protocols for geo-tagged photographs for use of VGI in relation to land cover applications.

Reliability and Security Issues for IoT-based Smart Business Center: Architecture and Markov Model

Abstract: One of the key subsystems from point of view of security of the complex IoT system is the smart business center (SB?) system. Some problems the design and operation of the SBC system are analyzed. When analysis of safety of the IoT system must take into account the reliability and security of the system at several levels: the level of sensors, the level of communication (communication lines, router, switch), the server level as the control device of components of the network, the level of the entire SBC subsystem. General architecture of network of the SB? is described. Reliability and security of key SB? hardwareand software manufacturers are analysed. In particular, security issue for SB? routers is considered. Shown the Markov model, which takes into account the technical conditions of typical network components of the SBC with the presence of software vulnerabilities when exposed to hacker attacks. On this model's basis it is possible to conduct further researches directed for improving the reliability operation and safety of IoT.

Volunteered geographic information measuring quality, understanding the value

Abstract: Oggi la Volunteer Geographic Information (VGI) e onnipresente. Proviene da varie fonti e puo essere trovata in molti aspetti tra cui toponimi, tracce GPS, foto geo-tag, applicazioni di social networking, blog, misurazioni dei sensori, mappe topografiche ecc. Puo essere il frutto di un lavoro sul campo o di bulk data importati da un dataset autorevole, disponibile gratuitamente. E' ovvio che tutte queste fonti non possono solo cadere in un'unica categoria. Ci sono molti aspetti che possono essere esaminati qui, ma di particolare interesse, quando si esaminano le fonti e le tipologie di VGI, sono l'origine, la motivazione e lo scopo di chi contribuisce alla VGI.

Pressure distension in leg vessels as influenced by prolonged bed rest and a pressure habituation regimen

Abstract: Bed rest increases pressure distension in arteries, arterioles, and veins of the leg. We hypothesized that bed-rest-induced deconditioning of leg vessels is governed by the removal of the local increments in transmural pressure induced by assuming erect posture and, therefore, can be counteracted by intermittently increasing local transmural pressure during the bed rest. Ten men underwent 5 wk of horizontal bed rest. A subatmospheric pressure (-90 mmHg) was intermittently applied to one lower leg [pressure habituation (PH) leg]. Vascular pressure distension was investigated before and after the bed rest, both in the PH and control (CN) leg by increasing local distending pressure, stepwise up to +200 mmHg. Vessel diameter and blood flow were measured in the posterior tibial artery and vessel diameter in the posterior tibial vein. In the CN leg, bed rest led to 5-fold and 2.7-fold increments (P < 0.01) in tibial artery pressure-distension and flow responses, respectively, and to a 2-fold increase in tibial vein pressure distension. In the PH leg, arterial pressure-distension and flow responses were unaffected by bed rest, whereas bed rest led to a 1.5-fold increase in venous pressure distension. It thus appears that bed-rest-induced deconditioning of leg arteries, arterioles, and veins is caused by removal of gravity-dependent local pressure loads and may be abolished or alleviated by a local pressure-habituation regimen.

Citizens as experts in a Greek political audience discussion program

Abstract: This article sets out to explore the type of discourses produced by participating citizens in a Greek political audience discussion program, capitalizing on different aspects of the economic crisis that has afflicted Greece since 2010. Departing from the dichotomy between abstract, expert talk and the ordinary discourse of personal experience postulated in the 1990s, and the subsequent transformations of ‘ordinariness’ in current broadcast output, this paper examines the situated performances of citizens in a concrete political broadcast format at a particular moment in time. This moment is characterized by economic crisis, as the overarching societal condition which legitimizes ordinary expertize by endowing citizens with increased conversational rights, compared to what is typical of citizen participation in political panel discussions with an audience in other European contexts, and the entitlement to engage in authoritative forms of talk. By drawing on discourse analysis and conversation analysis of sequences of TV talk, the analysis unveils the rhetorical strategies, as well as the evidential devices and forms of knowledge projected in citizen talk. Finally, the article calls attention to the implications of these forms of discursive participation for empowering the role of citizens in political communication, public dialog and democratic debate.

Real Hypersurfaces in Non-Flat Complex Space form with Structure Jacobi Operator of Lie-Codazzi Type

Abstract: In this paper the notion of Lie-Codazzi type of a tensor field T of type (1,1) on real hypersurfaces, which generalizes the notion of Lie parallel, is introduced. Real hypersurfaces in non-flat complex space forms, whose structure Jacobi operator is of Lie-Codazzi type, are studied. More precisely, the non-existence of such real hypersurfaces is proved.

The structure Jacobi operator of three-dimensional real hypersurfaces in non-flat complex space forms

Abstract: In this paper new results concerning three dimensional real hypersurfaces in non-flat complex space forms in terms of their stucture Jacobi operator are presented. More precisely, the conditions of 1) the structure Jacobi operator being of Codazzi type with respect to the generalized Tanaka-Webster connection and commuting with the shape operator and 2) η-invariance of the structure Jacobi operator and commutativity of it with the shape operator are studied. Furthermore, results concerning Hopf hypersurfaces and ruled hypersurfaces of dimension greater than three satisfying the previous conditions are also included.

Conditions of parallelism of *-Ricci tensor of three dimensional real hypersurfaces in non-flat complex space forms

Abstract: This paper focuses on the study of three dimensional real hypersurfaces in non-flat complex space forms whose $^{*}$-Ricci tensor satisfies conditions of parallelism. More precisely, extension of existing results concerning real hypersurfaces with vanishing, semi-parallel and pseudo-parallel $^{*}$-Ricci tensor in case of ambient space being the complex hyperbolic space are provided. Furthermore, new results concerning $\xi$-parallelism of $^{*}$-Ricci tensor of real hypersurfaces in non-flat complex space forms are presented.

Erasure Code for Efficient Error Correction in Block Data Transmission

Abstract: This paper proposes an innovative technique for correcting transmission burst errors in data transmitted over amplitude modulated channels suffering from strong electromagnetic interference, such as encountered in military situations. Efficiency is achieved by separating the error detection from the correction process and using different codes for each case. The proposed technique is based on simple mathematical operations and is suitable for implementation in FPGA devices. It is shown to be more efficient than existing ones, according to criteria that are relevant to current applications.