24 research outputs found

    Power Management Support to Optimal Duty-Cycling in Stateful Multitasking WSN

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    The present work proposes a power management infrastructure for WSN, with support for heterogeneous, concurrent applications that need to preserve their status during deep-idle periods. There are two main original contributions: i) the definition and implementation of an integrated and general power management infrastructure, transparent to the end user and supporting heterogeneous concurrent applications, ii) a rigorous model for the optimal choice of the power management policy, considering also set points at the lowest possible power state (power-off) with no memory retention. The power management infrastructure is based on the framework proposed in a previous work and this paper details the architecture and the interaction of its core modules. The whole system has been implemented on a prototype version of the PoliNode infrastructure and Miosix operating system. Results show energy gain up to 98%, varying with the period and size of the application

    A Lightweight Mechanism for Dynamic Linking in Wireless Sensor Networks

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    The implementation of high quality complex wireless sensor networks requires a good level of flexibility both at compile-time (configuration) and at run-time (management). The twofold goal is on one hand to improve the overall “fitness” of the application implemented to the changing environment and on the other hand to limit the footprint of the software. This paper presents a flexible and lightweight mechanism to implement dynamic linking of application modules over a wireless sensors network. The proposed approach is based on a client/server approach and a two-phases remote linking aimed at optimizing the resource usage on the network nodes. A prototypical implementation for MantisOS on TelosB nodes is also described

    Optimal hibernation policies for energy efficient stateful operation in high-end wireless sensor nodes

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    This paper proposes and studies an hibernation technique and optimal hibernation policies aimed at minimizing the power consumption, while allowing stateful processing and the adoption of more powerful nodes. To this purpose the paper models the energy trade-off for hibernating the system rather than putting it in a memory-retention sleep mode between two consecutive bursts of processing. Thanks to a simplified notion of system state, the paper formally determines the optimal conditions for deciding whether to hibernate or not the system during idle periods. Hibernation policies have been implemented as a module of the operating system and results demonstrate energy savings up to 50% compared to trivial hibernation approaches. Moreover, the hibernation policy proved to be robust and stable with respect to changes of the application parameters

    Power-Efficient Software Allocation in Wireless Sensor Networks

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    The present work concentrates on the formulation of a model and a heuristic for generating, respectively, optimal and sub-optimal software allocations to maximize the lifetime of Wireless Sensor Networks. This is achieved by minimizing and balancing the energy consumption, while preserving the completeness of the application and the resilience against pqfguÓ faults. In the considered scenario a node can schedule and execute multiple functions, either stored on its Flash memory or dynamically retrieved from the base station or the cluster head, through a dynamic reprogramming mechanism. Execution is guaranteed by a distributed scheduling mechanism, capable of orchestrating the execution of a given function among all the nodes on which that function is run, so that its execution frequency is guaranteed and the overall energy consumption minimized by exploiting parallelism among nodes. Both the model and the heuristic include constraints on the available memory and the desired execution frequency of functions, as well as routing and overhearing issues. The main result of the proposed work is a framework to efficiently define the software allocation on a WSN under power-consumption constraints, encompassing also more evolved architectures, equipped with a dynamic reprogramming mechanism, multitasking nodes and a distributed schedule

    Impaired gait kinematics in type 1 Gaucher's Disease

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    Type 1 Gaucher's disease (GD1) is traditionally regarded as "non-neurological". Spatiotemporal and kinematic analysis of gait was carried on thirteen GD1 patients and thirteen healthy controls. We identified a previously unknown subclinical reduction of amplitude of movements in GD1. Articular excursion of ankle, knee and hip was reduced during the swing phase of gait (p <  0.0001). Furthermore, the excursion of the knee appeared also significantly more asymmetric in GD1 patients (p = 0.02). Correction for age, BMI and basal walking speed did not modify the significance. Accordingly to the recent observations that GD1 predisposes to Parkinson's disease, the impaired and asymmetric gait kinematics that we observed might be interpreted as a form of extrapyramidal involvement
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