51 research outputs found

    Asynchronous Distributed Averaging on Communication Networks

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    Distributed algorithms for averaging have attracted interest in the control and sensing literature. However, previous works have not addressed some practical concerns that will arise in actual implementations on packet-switched communication networks such as the Internet. In this paper, we present several implementable algorithms that are robust to asynchronism and dynamic topology changes. The algorithms are completely distributed and do not require any global coordination. In addition, they can be proven to converge under very general asynchronous timing assumptions. Our results are verified by both simulation and experiments on Planetlab, a real-world TCP/IP network. We also present some extensions that are likely to be useful in applications

    Trunk Control Response to Unstable Seated Posture During Various Feedback Conditions in People with Chronic Low Back Pain

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    AIMS: People with chronic low back pain (CLBP) tend to have altered postural control. Visual biofeedback may be used to restore postural control. The purpose of this pilot study was to investigate the effect of visual biofeedback on seated postural trunk control in subjects with CLBP, and to investigate the relationship between the postural control parameters and clinical tests. METHODS: Ten CLBP subjects (8 female, 2 male; age 40.6±5 yrs; BMI 25.06±2.93) and 10 healthy matched controls (8 female, 2 male; age 41.2±5.88 yrs; BMI 24.61±3.17) underwent seated postural assessment. Center of pressure (COP) parameters were collected under three experimental conditions: eyes-open, visual biofeedback, and eyes-closed. RESULTS: The results revealed that COP velocity was significantly different between healthy and CLBP subjects for each condition, both healthy and CLBP subjects had no differences in COP parameters between eyes-open and visual biofeedback conditions, and in subjects with CLBP, the straight leg raise clinical test had a strong negative correlation with all COP parameters. CONCLUSIONS: Our results suggest that 30-second visual biofeedback training did not improve the seated postural control of CLBP subjects, potentially due to the short duration of training, and that hamstrings muscle tightness or decreased sciatic nerve mobility was associated with worse postural control. J Allied Health 2019; 48(1):54–60

    In-Network Outlier Detection in Wireless Sensor Networks

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    To address the problem of unsupervised outlier detection in wireless sensor networks, we develop an approach that (1) is flexible with respect to the outlier definition, (2) computes the result in-network to reduce both bandwidth and energy usage,(3) only uses single hop communication thus permitting very simple node failure detection and message reliability assurance mechanisms (e.g., carrier-sense), and (4) seamlessly accommodates dynamic updates to data. We examine performance using simulation with real sensor data streams. Our results demonstrate that our approach is accurate and imposes a reasonable communication load and level of power consumption.Comment: Extended version of a paper appearing in the Int'l Conference on Distributed Computing Systems 200

    Management and outcomes of unilateral group d tumors in retinoblastoma

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    Purpose: Retinoblastoma presents most commonly as advanced unilateral disease, particularly in developing countries for which primary enucleation has been the preferred method of treatment. However, with the evolution of newer treatment modalities including intravitreal chemotherapy, intra-arterial chemotherapy and newer chemotherapeutic combinations, a trend towards more conservative approaches is being observed. Our aim is to evaluate outcomes of group D eyes following conservative and non-conservative treatment options. Patients and Methods: The ocular oncology database was used to identify eyes with unilateral retinoblastoma that fulfilled the International Intraocular Retinoblastoma Classification (IIRC) group D criteria from August 2010 to August 2018 and these were retrospectively reviewed. Overall, 39 eyes were identified. Results: Nineteen (49%) eyes underwent primary enucleation and 20 (51%) received eyeconserving treatment. Eye salvage was possible in 15 (75%) eyes in the attempted salvage group. None of the patient revealed signs of metastasis. All eyes received conventional chemotherapy (carboplatin, vincristine, etoposide) and focal laser therapy. Additional treatment modalities offered included intravitreal chemotherapy, intra-arterial chemotherapy and topotecan. Three (11%) eyes in the primary enucleation group showed high-risk features on histopathology and none developed metastasis. Conclusion: The results of the study seem promising and conservative measures can be adopted in selected unilateral group D eyes

    Utilization of galactomannan from Gleditsia triacanthos in polysaccharide-based films : effects of interactions between film constituents on film properties

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    The objective of this work was to evaluate the effect of the concentrations of Gleditsia triacanthos galactomannan and glycerol and the presence of corn oil in the physical properties of edible films. The influence of interactions between those constituents on films' permeability to gases (water vapour, CO2 and O2), solubility in water, mechanical properties and colour was evaluated. The effects of those variables were analysed according to a 23 factorial design; regression coefficients were used to understand the influence of each variable (factor) on the studied properties, and a multifactor model was developed. Results show that galactomannan concentration is the most significant factor affecting the studied properties; moreover, the increase of plasticizer concentration and the presence of oil showed to be the most influent in the particular cases of solubility and transport properties (water vapour permeability and O2 permeability), respectively. These results show that galactomannan films' properties can be tailored to allow their use as alternative to non-biodegradable, non-edible packaging materials.The author M. A. Cerqueira is recipient of a fellowship from Fundacao para a Ciencia e Tecnologia (FCT, SFRH/BPD/72753/2010) and B. W. S. Souza is a recipient of a fellowship from the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior, Brazil (Capes, Brazil)

    Performance, Carcass Characteristics, and Meat Quality of Broiler Chickens Fed β-Mannanase and Two Levels of Energy

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    This study aimed at evaluating the response to supplementation of β-Mannanase with two levels of energy on performance, carcass yield, and meat quality of 1600 1-d-old straight run Indian River broilers which were randomly allotted to 4 dietary treatments (10 replicates/treatment, 40 chicks per replicate) in a 35-d feeding trial. The trial consisted of 2 phases, starter (0 to 14 d) and grower (15 to 35 d). The experiment was designed in a 2 x 2 factorial arrangement. The first factor was the energy level of the ration consisted of 2 levels, i.e., a low energy level with 2.900 kcal ME/kg during the starter phase and 3.000 kcal ME/kg during the grower phase; and a normal energy level with 3020 kcal ME/kg during starter phase and 3120 kcal ME/kg during grower phase, with variations based on the content of feed grade soybean oil. The second factor was the level of β-Mannanase in the diet consisted of 2 levels, i.e., ration without β-Mannanase (BETAMINUS: 0%) and ration with 0.05% β-Mannanase (BETAPLUS: 0.05%). Feeding low ME increased feed intake (p<0.05) during the overall phase (0 to 35 d) and normal ME decreased (p<0.05) feed conversion ratio during the starter and overall phases. Birds fed normal ME exhibited higher (p<0.05) hot and cold carcass weights. There was a significant interaction between dietary ME level and β-Mannanase to breast meat pH (p= 0.006), meat redness (a*) (p= 0.01), and meat yellowness (b*) (p= 0.0001). In conclusion, the results of enzyme supplementation did not elicit any noticeable response pertaining to productive performance, carcass characteristics, or meat quality (except pH and meat color). Moreover, feeding low dietary ME and β-Mannanase did not compromise overall broiler chickens performance

    Spanning Tree or Gossip for Aggregation: A Comparative Study

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    Abstract. Distributed aggregation queries like average and sum can be imple-mented in several different paradigms including gossip and hierarchical approaches. In the literature, these two paradigms are routinely associated with stereotypes such as “trees are fragile and complicated ” and “gossip is slow and expensive”. However, a closer look reveals that these statements are not backed up by thor-ough studies. A fair and informative comparison is clearly needed. However, it is a very hard task, because the performance of protocols from the two paradigms depends on different subtleties of the environment and the implementation of the protocols. We tackle this problem by carefully designing the comparison study. We use state-of-the-art algorithms and propose the problem of monitoring the network size in the presence of churn as the ideal problem for comparing very different paradigms for global aggregation. Our experiments help us identify the most important factors that differentiate between gossip and spanning tree aggre-gation: the time needed to compute a truly global output, the properties of the underlying topology, and the sensitivity to dynamism. We demonstrate the effect of these factors in different practically interesting topologies and scenarios. Our results help us to choose the right protocol in the knowledge of the topology and dynamism patterns.
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