550 research outputs found

    Task allocation in group of nodes in the IoT: A consensus approach

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    The realization of the Internet of Things (IoT) paradigm relies on the implementation of systems of cooperative intelligent objects with key interoperability capabilities. In order for objects to dynamically cooperate to IoT applications' execution, they need to make their resources available in a flexible way. However, available resources such as electrical energy, memory, processing, and object capability to perform a given task, are often limited. Therefore, resource allocation that ensures the fulfilment of network requirements is a critical challenge. In this paper, we propose a distributed optimization protocol based on consensus algorithm, to solve the problem of resource allocation and management in IoT heterogeneous networks. The proposed protocol is robust against links or nodes failures, so it's adaptive in dynamic scenarios where the network topology changes in runtime. We consider an IoT scenario where nodes involved in the same IoT task need to adjust their task frequency and buffer occupancy. We demonstrate that, using the proposed protocol, the network converges to a solution where resources are homogeneously allocated among nodes. Performance evaluation of experiments in simulation mode and in real scenarios show that the algorithm converges with a percentage error of about±5% with respect to the optimal allocation obtainable with a centralized approach

    Energy consumption management in Smart Homes: An M-Bus communication system

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    Energy consumption management in Smart Home environments relies on the implementation of systems of cooperative intelligent objects named Smart Meters. In order for devices to cooperate to smart metering applications' execution, they need to make their information available. In this paper we propose a framework that aims at managing energy consumption of controllable appliances in groups of Smart Homes belonging to the same neighbourhood or condominium. We consider not only electric power distribution, but also alternative energy sources such as solar panels. We define a communication paradigm based on M-Bus for the acquisition of relevant data by managing nodes. We also provide a lightweight algorithm for the distribution of the available alternative power among houses. Performance evaluation of experiments in simulation mode prove that the proposed framework does not jeopardise the lifetime of Smart Meters, particularly in typical situations where managed devices do not continuously turn on and off

    Objects that agree on task frequency in the IoT: A lifetime-oriented consensus based approach

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    Some key features of the end-systems impact on the way communications happen within the IoT: available objects' resources are limited, different objects may provide the same information (e. g. sense the same physical measure), the number of nodes in the IoT is quickly overcoming the number of Internet hosts with greater reliability issues. This entails for a new paradigm of communication with respect to those characterizing the traditional Internet. Before providing the required information about the physical world, objects coordinate with the other objects in groups and provide a unified service to the external world (the application that requires the service), with the intent to distribute the load of the requested services according to specific community defined rules, which could be: lifetime extension, QoS (Quality of Service) maximization, reward maximization, or others. In this paper other than describing the characteristics of this new communication paradigm and challenges it is called to address, we also propose a first solution for its implementation that relies on a distributed optimization protocol based on the consensus algorithm. Results of simulations and real experiments are also presented that show the viability in implementing the new communication model in a distributed way

    Peri-implant diseases and metabolic syndrome components: a systematic review

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    OBJECTIVE: Metabolic syndrome (MetS) is defined as a spectrum of conditions associated with an increased risk of developing CVD and type 2 diabetes. MetS include: hyperglycemia, hypertension, visceral obesity, dyslipidemia with elevated values of triglycerides (TG) and low levels of HDL. The aim of this review is to provide current knowledge of the relationship between MetS, its components and peri-implant diseases. MATERIALS AND METHODS: An electronic literature search was conducted in the English language in several databases. The Newcastle-Ottawa Scale was used for quality assessment of cohort and cross-sectional studies; while systematic reviews were evaluated through AMSTAR; results were reported according to the PRISMA Statement. RESULTS: A total of 272 records were identified through database searching, six studies were included for qualitative analysis. No study directly related to MetS was found, there was inconsistent and controversial evidence regarding association with cardiovascular disease. A higher risk of peri-implantitis was detected in people with hyperglycemia. CONCLUSIONS: Future research should be orientated in assessing the risk of peri-implant diseases, evaluating patient's therapeutic response, analyzing directionality of the relationship between MetS, its components and biologic implant complications. Few studies have investigated the possible relationship between systemic conditions and peri-implant diseases. The aim of this review is to present, in a systematic manner, current evidence and knowledge regarding possible association between cardiovascular disease and implant biologic complications. Out of the one-hundred-eighty-nine studies screened, just five studies were selected for qualitative analysis: three cohort studies (one prospective and two retrospectives) and two cross-sectional studies. According to their results, there is inconsistent and controversial evidence regarding association of cardiovascular disease and implant biologic complications. Future research should be orientated in conducting longitudinal studies, evaluating patients affected by cardiovascular disease rehabilitated with dental implants

    Estimating carbon dioxide fluxes from temperate mountain grasslands using broad-band vegetation indices

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    The broad-band normalised difference vegetation index (NDVI) and the simple ratio (SR) were calculated from measurements of reflectance of photosynthetically active and short-wave radiation at two temperate mountain grasslands in Austria and related to the net ecosystem CO<sub>2</sub> exchange (NEE) measured concurrently by means of the eddy covariance method. There was no significant statistical difference between the relationships of midday mean NEE with narrow- and broad-band NDVI and SR, measured during and calculated for that same time window, respectively. The skill of broad-band NDVI and SR in predicting CO<sub>2</sub> fluxes was higher for metrics dominated by gross photosynthesis and lowest for ecosystem respiration, with NEE in between. A method based on a simple light response model whose parameters were parameterised based on broad-band NDVI allowed to improve predictions of daily NEE and is suggested to hold promise for filling gaps in the NEE time series. Relationships of CO<sub>2</sub> flux metrics with broad-band NDVI and SR however generally differed between the two studied grassland sites indicting an influence of additional factors not yet accounted for

    Merkel cell carcinoma with an unusual immunohistochemical profile

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    The clinical and morphological picture of Merkel cell carcinoma (MCC) may be rather challenging; therefore, the immunohistochemical profile plays a relevant role in confirming the microscopic diagnosis. A panel of antibodies including cytokeratins 20, 7 and epithelial membrane antigen, and neuron-specific enolase is used in confirming the morphological diagnosis of MCC. The majority of MCCs express CK20 and are CK7-negative. Herein, we present a case of primary cutaneous neuroendocrine carcinoma with an atypical immunohistochemical pattern. A 83-years old woman presented with a painless plaque, red to violaceous in colour, located in the leg. The skin tumor was excided, formalin-fixed and paraffinembedded. Tissue sections were immunostained with a panel of antibodies routinely utilized in complex primary skin tumors for evidencing epithelial and neuroendocrine differentiation of tumor cells. The neuroendocrine differentiation of tumor cells was evidenced by their immunoreactivity for synaptophysin, chromograninA and neuron-specific enolase. Tumor cells also showed diffuse cytoplasmic staining for CK7. No immunoreactivity was detected for CK20 and thyroid transcription factor-1. Our data, together with previous rare reports of CK20−/CK7+ MCCs, lay stress on the importance of routinely utilizing a panel of antibodies in the differential diagnosis of complex primary carcinomas of the skin and may have important implications in expanding the differential diagnosis of skin tumors. In particular, caution should be taken in excluding the diagnosis of MCC only on the basis of the absence of reactivity of tumor cells for CK20, favouring the wrong diagnosis of less aggressive skin tumors

    On the η\eta and η′\eta' Photoproduction Beam Asymmetry at High Energies

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    We show that, in the Regge limit, beam asymmetries in η\eta and η′\eta' photoproduction are sensitive to hidden strangeness components. Under reasonable assumptions about the couplings we estimate the contribution of the ϕ\phi Regge pole, which is expected to be the dominant hidden strangeness contribution. The ratio of the asymmetries in η′\eta' and η\eta production is estimated to be close to unity in the forward region 0<−t/GeV2≤10 < -t/\text{GeV}^2 \leq 1 at the photon energy Elab=9E_\text{lab} = 9~GeV, relevant for the upcoming measurements at Jefferson Lab.Comment: 9 pages, 4 figure

    Structure of Pion Photoproduction Amplitudes

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    We derive and apply the finite energy sum rules to pion photoproduction. We evaluate the low energy part of the sum rules using several state-of-the-art models. We show how the differences in the low energy side of the sum rules might originate from different quantum number assignments of baryon resonances. We interpret the observed features in the low energy side of the sum rules with the expectation from Regge theory. Finally, we present a model, in terms of a Regge-pole expansion, that matches the sum rules and the high-energy observables.Comment: 19 pages, 15 figures and 4 table

    A nose for trouble.

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    A 63‑year‑old Caucasian non‑smoker presented with purplish, firm, slowly growing plaques on the nose, of 20 years duration. The bigger one involved the upper part of the nose in its entirety [Figure 1], while there were smaller ones on the left and right cheek. All the plaques were asymptomatic and did not worsen after sunlight exposure. His past medical history was unremarkable. Hematological and biochemical parameters were within normal limits. Histological examination revealed a diffuse mid‑dermal cellular infiltrate composed of neutrophils, eosinophils, plasma cells, and lymphocytes. A narrow Grenz zone was present. In the lower part of the reticular dermis, the mixed infiltrate was intermingled with a massive deposition of fascicled pattern collagen fibers and spindle cell
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