Search results for "Protocol"
showing 10 items of 1808 documents
Verifying a medical protocol with temporal graphs: the case of a nosocomial disease.
2014
Abstract Objective Our contribution focuses on the implementation of a formal verification approach for medical protocols with graphical temporal reasoning paths to facilitate the understanding of verification steps. Materials and methods Formal medical guideline specifications and background knowledge are represented through conceptual graphs, and reasoning is based on graph homomorphism. These materials explain the underlying principles or rationale that guide the functioning of verifications. Results An illustration of this proposal is made using a medical protocol defining guidelines for the monitoring and prevention of nosocomial infections. Such infections, which are acquired in the h…
Formal Modeling and Discrete-Time Analysis of BPEL Web Services
2008
International audience; Web services are increasingly used for building enterprise information systems according to the Service Oriented Architecture (SOA) paradigm. We propose in this paper a tool-equipped methodology allowing the formal modeling and analysis of Web services described in the BPEL language. The discrete-time transition systems modeling the behavior of BPEL descriptions are obtained by an exhaustive simulation based on a formalization of BPEL semantics using the Algebra of Timed Processes (ATP). These models are then analyzed by model checking value-based temporal logic properties using the CADP toolbox. The approach is illustrated with the design of a Web service for GPS na…
Identification of Synaptic Integration Mode in CA3 Pyramidal Neuron Model
2019
International audience; A morphologically realistic and anisotropic model of CA3 pyramidal neuron was developed to determine the synaptic integration modes the neuron is able to perform. Linearity and nonlinearity were identified in different synaptic locations with varying active mechanisms such as the presence of ionic channels in the dendritic arbor and the types of receptors in the synapse. Quantification of synaptic integration was performed using paired-pulse stimulation protocol and subthreshold input/output (sI/O) transformation. Results show that the mode of synaptic integration is location-dependent while the linearity or nonlinearity in the integration is mainly influenced by the…
Effects of school-based interventions on motivation towards physical activity in children and adolescents: Protocol for a systematic review
2019
Background Recent studies have observed low levels of physical activity in children and adolescents worldwide. Physical activity interventions are increasingly carried out to counteract this development. The school environment is an ideal setting for such interventions to take place as large numbers of children and adolescents can be addressed. With the assumption that motivation is the key to initiate and sustain beneficial health behaviors, theory-based intervention studies apply motivational strategies to increase students’ participation in physical activity. The main objective of this systematic review will be to analyze the effects of school-based physical activity interventions on a v…
An Efficient Distributed Algorithm for Generating Multicast Distribution Trees
2005
Multicast transmission may use network resources more efficiently than multiple point-to-point messages; however, creating optimal multicast trees (Steiner Tree Problem in Networks) is prohibitively expensive. For this reason, heuristic methods are generally employed. Conventional centralized Steiner heuristics provide effective solutions, but they are unpractical for large networks, since they require complete knowledge of the network topology. This paper proposes a distributed algorithm for the heuristic solution of the Steiner Tree Problem. The algorithm allows the construction of effective distribution trees using a coordination protocol among the network nodes. The algorithm has been i…
Enabling Retransmissions for Achieving Reliable Multicast Communications in WSNs
2016
To ensure end-to-end reliable multicast or broadcast transmissions in IEEE 802.15.4 based wireless sensor networks WSNs) is a challenging task since no retransmission and acknowledgment mechanisms are defined in such WSNs. In this paper, we propose three retransmission enabled multicast transmission schemes in order to achieve reliable packet transmissions in such networks. Different from the legacy CSMA/CA principle, these schemes allow a sending or forwarding node to retransmit a packet if necessary and enable implicit or/and explicit acknowledgment for multicast services. Simulations are performed in order to assess the performance of these schemes in terms of number of retransmissions, …
Multicast TV over WLAN in a University Campus Network
2009
One of the multimedia services offered by the campus network of the Polytechnic University of Valencia is TV over IP. This service works well in the devices connected directly to the wired network but we have detected some problems when the receivers access to the campus network through wireless IEEE 802.11, especially when devices roam across the Campus. In this paper we propose and evaluate a server-based solution to minimize the packet loss and reduce the lack of service when the mobile devices roam from an Access Point to another Access Point in the wireless network. This solution uses a location system to modify the behaviour of standard multicasting protocols in order to get a near-se…
Multicast access control concept for xDSL-customers
2006
Multicast is a tempting possibility for many broad- band services. It makes possible to deliver one data-stream to several receivers simultaneously. IP-Multicast is based on an open group concept. This means that it is possible for all the users to join the group and thus receive the data. The open concept is also the main reason why multicast has not been taken in wider use. There is two different solution to solve this problem, group access control and multicast data encryption. Group access control mechanisms focuses on restricting the group membership at the users edge device. Traffic encryption scheme relies on end-to-end encryption, so a key management architecture is also needed. We …
Quality of Service Multicasting over Differentiated Services Networks
2003
This paper proposes a solution to support real-time multicast traffic with Quality of Service (QoS) constraints over Differentiated Services (DiffServ) IP networks. Our solution allows multicast users to dynamically join and leave the multicast tree. Moreover, it allows a multicast user which has negotiated a best-effort session to upgrade to a QoS-enabled session. Our solution is backward compatible with the Protocol Independent Multicast (PIM) scheme. It combines two ideas. First, resource availability along a new QoS path is verified via a probe-based approach. Second, QoS is maintained by marking replicated packets with a special DSCP value, before forwarding them on the QoS path.
Multicast polling and efficient voip connections in ieee 802.16 networks
2007
IEEE 802.16 standard defines the wireless broadband access network technology called WiMAX which introduces several interesting advantages including its the support for quality of service (QoS) at the MAC layer. Its several features, such as multicast polling support the base station (BS) to provide the QoS guarantees for subscriber stations (SSs). The specification, however, does not define very exactly how this optional multicast polling technique should be used. We propose a way to use this feature on the base stations and also suggest an addition to the specification, to serve several different delay requirements. To test the proposed solution and the performance of the multicast pollin…