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a b s t r a c tStringent cost and energy constraints impose the use of low-cost and low-power radio transceivers in large-scale wireless sensor networks (WSNs). This fact, together with the harsh characteristics of the physical environment, requires a rigorous WSN design. Mechanisms for WSN deployment and topology control, MAC and routing, resource and mobility management, greatly depend on reliable link quality estimators (LQEs). This paper describes the RadiaLE framework, which enables the experimental assessment, design and optimization of LQEs. RadiaLE comprises (i) the hardware components of the WSN testbed and (ii) a software tool for setting-up and controlling the experiments, automating link measurements gathering through packets-statistics collection, and analyzing the collected data, allowing for LQEs evaluation. We also propose a methodology that allows (i) to properly set different types of links and different types of traffic, (ii) to collect rich link measurements, and (iii) to validate LQEs using a holistic and unified approach. To demonstrate the validity and usefulness of RadiaLE, we present two case studies: the characterization of low-power links and a comparison between six representative LQEs. We also extend the second study for evaluating the accuracy of the TOSSIM 2 channel model.
This paper tackles the problem of ever changing embedded systems non-functional requirements, specially the architectural ones. It proposes a solution based on Features Model and MDA standards, which is called FeaturesOriented Model-Driven Architecture (FOMDA). This proposal can be used to help application designer in defining the mappings and transformations of UML models to as many target platforms as wished. This is done by configuring model-to-model and model-to-code transformations over tiers, where every tier represents some target platform properties that the system must be mapped and transformed to. To validate the proposal a case study related to the development of an embedded real-time system is presented, detailing how to transform a generic high-level UML model to a model specific for a given target platform. Obtained results are optimistic and conclude that the FOMDA approach can make designers re-think their current development process to make it more decoupled from a specific target platform.
This paper presents a new approach to the automatic identification of objects / classes from a system specification. The methodology is aimed at the development of Distributed Real-Time Systems (DRTS), specially those conceived for industrial automation applications. UML is used as the modeling language in conjunction with an extended version of traditional DFD (E-DFD), that conveys information on flow type (data or control) and on process complexity and timing constraints. E-DFDs are mapped into a graph and a tool is used to carry out an automatic graph partition, which allows the identification of a set of objects that constitute, from the design and test points of view, the 'best-fitted' architecture. To validate the proposed methodology, a case study is presented and analyzed, comparing two design strategies.
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