151 research outputs found

    FDI spill-overs in the Estonian economy: a trade performance analysis

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    The present thesis investigates the hypothesis of FDI export spill-overs from foreign multinationals to domestic Estonian companies by using a dataset comprising both exporters and non-exporters in the manufacturing sectors in a time-span ranging from 1999 to 2009. Estonia is an excellent case study in the field thanks to its historically high levels of FDI per capita. The study assesses both horizontal and vertical spill-overs, distinguishing the latter between backward and forward linkages. It starts by analysing FDI dynamics, previous studies on export spill-overs and the historical evolution of the Estonian economy. A Heckman selection model is then described and employed in order to distinguish between two different decisions, namely whether firms decide to start exporting or not (export-propensity) and how much they export (export-intensity). The results reveal a scarce significance of spill-overs in the decision to engage in exports, but various robustness checks confirm a strong relevance of backward linkages in export-intensity. These externalities seem to be stronger after EU accession. In contrast to the main findings of previous studies, horizontal spill-overs appear generally as insignificant even when controlled for time or technological heterogeneity in the dataset. Contrary to what usually found for developing and transitional markets, export-intensive Estonian firms are both younger and larger firms. This can be seen as a confirmation of successful institutional reforms during the years of transition, especially when integrated with earlier findings on Estonia by Sinani and Meyer (2004).http://www.ester.ee/record=b4502512*es

    Experimental study and modelling of Networked Virtual Environment server traffic

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    The paradigm of virtual world environment arises as an useful tool in diverse fields such as e-Health or education, where they provide a new way of communication and interaction with end users. Networking capabilities play an important role in these systems, which motivates the study and understanding of the gaming network traffic. The present work focuses on Open Wonderland, a system that provides the basis for the development of Networked Virtual Environments with educational or health purposes. The goal of this paper is defining a testing environment and modelling the behaviour of the outgoing network traffic at the server side.Ministerio de Industria, Comercio y Turismo AAL-010000-2012-10Ministerio de Ciencia e Innovación TEC2009-10639-C04-0

    Waterfall Traffic Classification: A Quick Approach to Optimizing Cascade Classifiers

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    Heterogeneous wireless communication networks, like 4G LTE, transport diverse kinds of IP traffic: voice, video, Internet data, and more. In order to effectively manage such networks, administrators need adequate tools, of which traffic classification is the basis for visualizing, shaping, and filtering the broad streams of IP packets observed nowadays. In this paper, we describe a modular, cascading traffic classification system—the Waterfall architecture—and we extensively describe a novel technique for its optimization—in terms of CPU time, number of errors, and percentage of unrecognized flows. We show how to significantly accelerate the process of exhaustive search for the best performing cascade. We employ five datasets of real Internet transmissions and seven traffic analysis methods to demonstrate that our proposal yields valid results and outperforms a greedy optimizer

    The last giant Araucaria trees in southern Brazil

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    Araucaria angustifolia (Bertol.) Kuntze is a native tree species of major importance in southern Brazil. It is a regional symbol due to its iconic shape and stature in the landscape; its wood was once economically important and its seeds are an important source of food for the fauna and are presently used in regional cuisine. Despite its importance and apparent abundance, the species is facing extinction mainly as a result of unregulated exploitation and deforestation. This study catalogued the remaining individuals in order to add to the body of knowledge available on A. angustifolia, a species that has become rare across its historic range. The circumference at breast height (1.30 m), the total height, and the tree volume were measured (3,529 araucarias). We catalogued trees with a large diameter measuring them in loco over three years involving a journey of more than 6,800 km. The volumes of these old trees are very large, ranging from 38.2 m3 to 106.6 m3. The largest A. angustifolia individual is located in the state of Santa Catarina and measures 3.25 m in diameter. The giant araucarias with > 2.00 m in diameter are rare and only 13 individuals could be found in southern Brazil; a priority action at the governmental level is to recognize and preserve these monumental trees and together with a need for a public policy of drawing up specific inventories of large trees

    Myocardial Deformation in Fontan Patients Assessed by Cardiac Magnetic Resonance Feature Tracking: Correlation with Function, Clinical Course, and Biomarkers

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    Cardiac MR (CMR) is a standard modality for assessing ventricular function of single ventricles. CMR feature-tracking (CMR-FT) is a novel application enabling strain measurement on cine MR images and is used in patients with congenital heart diseases. We sought to assess the feasibility of CMR-FT in Fontan patients and analyze the correlation between CMR-FT strain values and conventional CMR volumetric parameters, clinical findings, and biomarkers. Global circumferential (GCS) and longitudinal (GLS) strain were retrospectively measured by CMR-FT on Steady-State Free Precession cine images. Data regarding post-operative course at Fontan operation, and medication, exercise capacity, invasive hemodynamics, and blood biomarkers at a time interval ± 6 months from CMR were collected. Forty-seven patients underwent CMR 11 ± 6 years after the Fontan operation; age at CMR was 15 ± 7 years. End-diastolic volume (EDV) of the SV was 93 ± 37 ml/m2, end-systolic volume (ESV) was 46 ± 23 ml/m2, and ejection fraction (EF) was 51 ± 11%. Twenty (42%) patients had a single right ventricle (SRV). In single left ventricle (SLV), GCS was higher (p < 0.001), but GLS was lower (p = 0.04) than in SRV. GCS correlated positively with EDV (p = 0.005), ESV (p < 0.001), and EF (p ≤ 0.0001). GLS correlated positively with EF (p = 0.002), but not with ventricular volumes. Impaired GCS correlated with decreased ventricular function (p = 0.03) and atrioventricular valve regurgitation (p = 0.04) at echocardiography, direct atriopulmonary connection (p = 0.02), post-operative complications (p = 0.05), and presence of a rudimentary ventricle (p = 0.01). A reduced GCS was associated with increased NT-pro-BNP (p = 0.05). Myocardial deformation can be measured by CMR-FT in Fontan patients. SLVs have higher GCS, but lower GLS than SRVs. GCS correlates with ventricular volumes and EF, whereas GLS correlates with EF only. Myocardial deformation shows a relationship with several clinical parameters and NT-pro-BNP. Keywords: Biomarkers; CMR; CMR-FT; Fontan; Strai

    An Architecture for Securing Communications in Critical Infrastructure

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    7th International Conference on Data Communication Networking - DCNET 2016, , 26/07/2016-28/07/2016, Lisboa, PortugalThe disruption of communications in critical infrastructures could have a serious impact on the health, safety, security or economic well-being of citizens or even prevent the effective functioning of governments or other agencies. For this reason, in this paper we present a distributed architecture, named CYBERSENS, aimed at preventing, early detecting, and mitigating cyber attacks to critical infrastructure networks. CYBERSENS is an advanced IDS/IPS system specially tailored for securing communications in critical infrastructures. It"s federated architecture, the combination of misuse detection techniques and novel anomaly detection approaches, and the inclusion of mechanisms for self-obfuscation and self-protection, makes our proposal specially suitable for these scenarios.European Commissio

    Three-Dimensional Shapes of Spinning Helium Nanodroplets

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    A significant fraction of superfluid helium nanodroplets produced in a free-jet expansion have been observed to gain high angular momentum resulting in large centrifugal deformation. We measured single-shot diffraction patterns of individual rotating helium nanodroplets up to large scattering angles using intense extreme ultraviolet light pulses from the FERMI free-electron laser. Distinct asymmetric features in the wide-angle diffraction patterns enable the unique and systematic identification of the three-dimensional droplet shapes. The analysis of a large dataset allows us to follow the evolution from axisymmetric oblate to triaxial prolate and two-lobed droplets. We find that the shapes of spinning superfluid helium droplets exhibit the same stages as classical rotating droplets while the previously reported metastable, oblate shapes of quantum droplets are not observed. Our three-dimensional analysis represents a valuable landmark for clarifying the interrelation between morphology and superfluidity on the nanometer scale

    Experimental Analysis of ViLTE Service

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    Long-term evolution (LTE) is a broadband wireless cellular system currently available in about 200 countries. From the mobile network operator point of view, one of the most appealing characteristics of LTE is the possibility of providing the users with mobile broadband services like voice over LTE and video over LTE (ViLTE), with strict quality of service (QoS) guarantees. The success of such services, which usually require a subscription fee, is obviously tightly bound to the users' quality of experience (QoE), that must be significantly better than the quality perceived in case of free services. This paper attempts to evaluate the perceived quality of the ViLTE service. In more detail, we present the results of an experimental test–bed realised at one of the most popular italian MNO, aimed at evaluating the impact of several network layer QoS parameters on the QoE of the ViLTE service

    Distributed physical sensors network for the protection of critical infrastractures against physical attacks

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    The SCOUT project is based on the use of multiple innovative and low impact technologies for the protection of space control ground stations and the satellite links against physical and cyber-attacks, and for intelligent reconfiguration of the ground station network (including the ground node of the satellite link) in the case that one or more nodes fail. The SCOUT sub-system devoted to physical attacks protection, SENSNET, is presented. It is designed as a network of sensor networks that combines DAB and DVB-T based passive radar, noise radar, Ku-band radar, infrared cameras, and RFID technologies. The problem of data link architecture is addressed and the proposed solution described
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