Search results for "computer.internet_protocol"
showing 10 items of 168 documents
Refinements on IEEE 802.11 Distributed Coordination Function Modeling Approaches
2010
With the popularity of the IEEE 802.11 standards, many analytical saturation throughput studies for the distributed coordination function (DCF) have been reported. In this paper, we outline a number of issues and criticalities raised by previously proposed models. In particular, a careful look at backoff counter decrement rules allows us to conclude that, under saturation conditions, the slot immediately following a successful transmission can be accessed only by the station (STA) that has successfully transmitted in the previous channel access. Moreover, due to the specific acknowledgment (ACK) timeout setting adopted in the standard, the slot immediately following a collision cannot be ac…
An efficient distributed algorithm for generating and updating multicast trees
2006
As group applications are becoming widespread, efficient network utilization becomes a growing concern. Multicast transmission represents a necessary lower network service for the wide diffusion of new multimedia network applications. 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. This paper proposes a distributed algorithm for the heuristic solution of the Steiner Tree Problem, allowing the construction of effective distribution trees using a coordination protocol among the network nodes. Furthermore, we propose a novel distribut…
A new Media Access Control layer Quality of Service multicast scheme for IEEE 802.11s based wireless mesh networks
2014
Inderscience Publishers; International audience; We propose a new Media Access Control (MAC) layer enabling Quality of Service (QoS) multicast scheme for IEEE 802.11s networks, where a unicast routing protocol called HWMP (Hybrid Wireless Mesh Protocol) is defined. The HWMP protocol is more adapted for best effort traffic, that's why its usage is not suitable for real time multimedia applications. The goal of our proposed mechanism is to take into account multicast communication under QoS constraints for the IEEE 802.11s mesh networks where no QoS multicasting has been defined. Our multicasting scheme handles QoS guarantee for real time applications. Indeed, our scheme is based on finding t…
Ultra-Low Power Wake-up Radio for 5G IoT
2019
5G Internet of Things (5G IoT), which is currently under development by 3GPP, paves the way for connecting diverse categories of devices to the IoT via cellular networks. For battery-powered low-cost IoT devices, wake-up radio (WuR) appears as an eminent technique for prolonging the lifetime of such devices, thanks to its outstanding energy consumption performance. However, only some small-size battery-powered IoT devices are able to transmit to a cellular IoT base station (BS) directly. In this article, we present W2B-IoT, a prototype implementation of a WuR-based two-tier system, which bridges cellular IoT BS and WuR via a Bluetooth low energy (BLE)-enabled Android smartphone. Such a WuR-…
A Method of Three-Dimensional Visualization of Molecular Processes of Apoptosis
2014
Apoptosis or programmed cell death plays an important role in many physiological states and diseases. Detection of apoptotic cells, tracing the development of apoptosis, drug development and regulation of apoptosis are an important parts of basic research in medicine. A large number of models have been developed that are based on the differential equations of the chemical kinetics, and can be expressed in a uniform notation using some XML-based languages, such as SBML and CellML. We describe the CellML and the simulation environment OpenCell herein. These tools can display models schematically and output results in the form of graphs showing time dependencies of component concentrations. Ho…
Interoperability of B2B Applications
2011
This paper presents a Web-based data integration methodology and tool framework, called X-TIME, for the development of Business-to-Business (B2B) design environments and applications. X-TIME provides a data model translator toolkit based on an extensible meta model and XML. It allows the creation of adaptable semantic-oriented meta models to support the design of wrappers or reconciliators (mediators), taking into account characteristics of interoperable information systems, such as extensibility and composability. X-TIME defines a set of meta types which correspond to g meta level semantic descriptors of data models found in the Web. The meta types are organized in a generalization hierarc…
Managing IFC for civil engineering projects
2003
The "Industrial Foundation Classes" (IFC) are an ISO norm to define all components of a building in a civil engineering project. IFC files are textual files whose size can reach 100 megabytes. Several IFC files can coexist on the same civil engineering project. Due to their size, their handling and sharing is a complex task. In this paper, we present an approach to automatically identify business objects in the IFC files and simplify their visualization and manipulation on the Internet. We construct an IFC Viewer which transforms the IFC file into a XML IFC tree manipulated through the 3D visualization of the building. The IFC Viewer composed a web-based platform called ACTIVe3D BUILD SERVE…
Gaussian Process Regression (GPR) Representation in Predictive Model Markup Language (PMML)
2017
International audience; This paper describes Gaussian process regression (GPR) models presented in predictive model markup language (PMML). PMML is an extensible-markup-language (XML) -based standard language used to represent data-mining and predictive analytic models, as well as pre- and post-processed data. The previous PMML version, PMML 4.2, did not provide capabilities for representing probabilistic (stochastic) machine-learning algorithms that are widely used for constructing predictive models taking the associated uncertainties into consideration. The newly released PMML version 4.3, which includes the GPR model, provides new features: confidence bounds and distribution for the pred…
The problem of interoperability: A common data format for quantum chemistry codes
2007
A common format for quantum chemistry (QC), enhancing code interoperability and communication between different programs, has been designed and implemented. An XML-based format, QC-ML, is presented for representing quantities such as geometry, basis set, and so on, while an HDF5-based format is presented for the storage of large binary data files. Some preliminary applications that use the format have been implemented and are also described. This activity was carried out within the COST in Chemistry D23 project “MetaChem,” in the Working Group “A meta-laboratory for code integration in ab initio methods.” © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
A Formal Semantics and a Client Synthesis for a BPEL Service
2008
A complex Web service described with languages like BPEL4WS, consists of an executable process and its observable behaviour (called an abstract process) based on the messages exchanged with the client. The abstract process behaviour is non deterministic due to the internal choices during the service execution. Furthermore the specification often includes timing constraints which must be taken into account by the client. Thus given a service specification, we identify the synthesis of a client as a key issue for the development of Web services. To this end, we propose an approach based on (dense) timed automata to first describe the observable service behaviour and then to build correct inte…