1,720,963 research outputs found
Design and Implementation of a Service Discovery Architecture in Pervasive Systems
No full textThe availability of cheap wireless technologies,
which can be interconnected through the Internet, has paved
the way to a large fruition of (web) services and the
convergence of the Internet with mobile handheld devices. A
potential market opportunity could become concrete only if
users can easily locate and access the available services,
thorough support for Service Discovery. There are a number
of service discovery protocols and architectures incompatible
with each other and sometimes applicable to only specific
networks. Often the use of these protocols can be carried out
only by experienced users.
In this article we will describe an architecture implementing
Service Discovery for a Pervasive System, which is simple,
effective and compliant with standardization. Whenever a
generic user, equipped with his wireless or wired terminal, get
access into an IP Network, the Service Discovery service start
up finding all the available and suitable services which can be
accessed locally or remotely from that access point. This work
has resulted in the context of DAIDALOS (Designing
Advanced network Interfaces for the Delivery and
Administration of Location independent, Optimised personal
Services [1]), a project granted in the European 6th
Framework Research Programme, within the IST
(Information Society and Technology) thematic area
Modeling and Simulation of GNSS with NS2
No full textDeployment of GNSS systems has paved the way to
the provision of location-based and navigation services with
growing accuracy and reliability. The introduction of the Galileo
system besides the GPS and GLONASS will constitute a major
technological advance of strategical importance for Europe in
particular. In such context instruments for investigation in the
field of GNSS are perceived as particular important for the
research community. In this work we present simulations of
GNSS system based on NS2, a well known simulator in the field
of telecommunication and network technology. Namely, we have
implemented a model for calculation of positioning exploiting the
existing NS2 satellite network models. We added the delay model
of the ionosphere and the troposphere, the ionosphere and
troposphere delay correction model and navigation algorithm.
Performance of those models have been compared with those of a
well-know reference simulator, i.e. STK. This comparison shows
that NS2 models allows to better model location errors due to
diurnal TEC variations
A QoS architecture for DVB-RCS next generation satellite networks
No full textRapporto Tecnico CNRS-LAAS (France) N°05005, 13pp, January 200
A Cross-Layer Location-Based Approach for Mobile-Controlled Connectivity
Full text linkWe investigate into the potentiality of an enhanced Power and Location-based Vertical Handover (PLB-VHO) approach, based on a combination of physical parameters (i.e., location and power attenuation information), for mobile-controlled connectivity across UMTS and WLAN networks. We show that the location information in a multiparameter vertical handover can significantly enhance communication performance. In the presented approach a power attenuation map for the visited area is built and kept updated by exploiting the information sharing of power measurements with other cooperating mobile devices inside the visited networks. Such information is then used for connectivity switching in handover decisions. The analytical model for the proposed technique is first presented and then compared with a traditional Power-Based approach and a simplified Location-Based technique. Simulation results show the effectiveness of PLB-VHO approach, in terms of (i) network performance optimization and (ii) limitation of unnecessary handovers (i.e., mitigation of ping-pong effect)
Validation of a QoS Architecture for DVB/RCS Satellite Networks via the SATIP6 demonstration platform
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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