2,637 research outputs found
Automatic Intent-Based Secure Service Creation Through a Multilayer SDN Network Orchestration
Growing traffic demands and increasing security awareness are driving the
need for secure services. Current solutions require manual configuration and
deployment based on the customer's requirements. In this work, we present an
architecture for an automatic intent-based provisioning of a secure service in
a multilayer - IP, Ethernet, and optical - network while choosing the
appropriate encryption layer using an open-source software-defined networking
(SDN) orchestrator. The approach is experimentally evaluated in a testbed with
commercial equipment. Results indicate that the processing impact of secure
channel creation on a controller is negligible. As the time for setting up
services over WDM varies between technologies, it needs to be taken into
account in the decision-making process.Comment: Parts of the presented work has received funding from the European
Commission within the H2020 Research and Innovation Programme, under grant
agreeement n.645127, project ACIN
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Bayesian retrieval of complete posterior PDFs of oceanic rain rate from microwave observations
A new Bayesian algorithm for retrieving surface rain rate from Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) over the ocean is presented, along with validations against estimates from the TRMM Precipitation Radar (PR). The Bayesian approach offers a rigorous basis for optimally combining multichannel observations with prior knowledge. While other rain-rate algorithms have been published that are based at least partly on Bayesian reasoning, this is believed to be the first self-contained algorithm that fully exploits Bayesās theorem to yield not just a single rain rate, but rather a continuous posterior probability distribution of rain rate. To advance the understanding of theoretical benefits of the Bayesian approach, sensitivity analyses have been conducted based on two synthetic datasets for which the ātrueā conditional and prior distribution are known. Results demonstrate that even when the prior and conditional likelihoods are specified perfectly, biased retrievals may occur at high rain rates. This bias is not the result of a defect of the Bayesian formalism, but rather represents the expected outcome when the physical constraint imposed by the radiometric observations is weak owing to saturation effects. It is also suggested that both the choice of the estimators and the prior information are crucial to the retrieval. In addition, the performance of the Bayesian algorithm herein is found to be comparable to that of other benchmark algorithms in real-world applications, while having the additional advantage of providing a complete continuous posterior probability distribution of surface rain rate
Race Differences in Initial Presentation, Early Treatment, and 1-year Outcomes of Pediatric CrohnŹ¼s Disease: Results from the ImproveCareNow Network
BACKGROUND: Racially disparate care has been shown to contribute to suboptimal health care outcomes for minorities. Using the ImproveCareNow network, we investigated differences in management and outcomes of pediatric patients with Crohn's disease at diagnosis and 1-year postdiagnosis.
METHODS: ImproveCareNow is a learning health network for pediatric inflammatory bowel disease. It contains prospective, longitudinal data from outpatient encounters. This retrospective study included all patients with Crohn's disease ā¤21 years, September 2006 to October 2014, with the first recorded encounter ā¤90 days from date of diagnosis and an encounter 1 year Ā±60 days. We examined the effect of race on remission rate and treatment at diagnosis and 1 year from diagnosis using t-tests, Wilcoxon rank-sum tests, Ļ statistic, and Fisher's exact tests, where appropriate, followed by univariate regression models.
RESULTS: Nine hundred seventy-six patients (Black = 118 (12%), White = 858 (88%), mean age = 13 years, 63% male) from 39 sites were included. Black children had a higher percentage of Medicaid insurance (44% versus 11%, P < 0.001). At diagnosis, Black children had more active disease according to physician global assessment (P = 0.027), but not by short Pediatric Crohn's Disease Activity Index (P = 0.67). Race differences in treatment were not identified. Black children had lower hematocrit (34.8 versus 36.7, P < 0.001) and albumin levels (3.6 versus 3.9, P = 0.001). At 1 year, Black children had more active disease according to physician global assessment (P = 0.016), but not by short Pediatric Crohn's Disease Activity Index (P = 0.06).
CONCLUSIONS: Black children with Crohn's disease may have more severe disease than White children based on physician global assessment. Neither disease phenotype differences at diagnosis nor treatment differences at 1-year follow-up were identified
A Formal Framework for Modeling Trust and Reputation in Collective Adaptive Systems
Trust and reputation models for distributed, collaborative systems have been
studied and applied in several domains, in order to stimulate cooperation while
preventing selfish and malicious behaviors. Nonetheless, such models have
received less attention in the process of specifying and analyzing formally the
functionalities of the systems mentioned above. The objective of this paper is
to define a process algebraic framework for the modeling of systems that use
(i) trust and reputation to govern the interactions among nodes, and (ii)
communication models characterized by a high level of adaptiveness and
flexibility. Hence, we propose a formalism for verifying, through model
checking techniques, the robustness of these systems with respect to the
typical attacks conducted against webs of trust.Comment: In Proceedings FORECAST 2016, arXiv:1607.0200
Measuring Infrared SurfaceBrightness Fluctuation Distances with HST WFC3: Calibration and Advice
We present new calibrations of the near-infrared (near-IR) surface brightness fluctuation (SBF) distance method for the F110W ( ) and F160W ( ) bandpasses of the Wide Field Camera 3 Infrared Channel (WFC3/IR) on the Hubble Space Telescope. The calibrations are based on data for 16 early-type galaxies in the Virgo and Fornax clusters observed with WFC3/IR and are provided as functions of both the optical and near-infrared colors. The scatter about the linear calibration relations for the luminous red galaxies in the sample is approximately 0.10 mag, corresponding to a statistical error of 5% in distance. Our results imply that the distance to any suitably bright elliptical galaxy can be measured with this precision out to about 80 Mpc in a single-orbit observation with WFC3/IR, making this a remarkably powerful instrument for extragalactic distances. The calibration sample also includes much bluer and lower-luminosity galaxies than previously used for IR SBF studies, revealing interesting population differences that cause the calibration scatter to increase for dwarf galaxies. Comparisons with single-burst population models show that as expected, the redder early-type galaxies contain old, metal-rich populations, while the bluer dwarf ellipticals contain a wider range of ages and lower metallicities than their more massive counterparts. Radial SBF gradients reveal that IR color gradients are largely an age effect; the bluer dwarfs typically have their youngest populations near their centers, while the redder giant ellipticals show only weak trends and in the opposite sense. Because of the population variations among bluer galaxies, distance measurements in the near-IR are best limited to red early-type galaxies. We conclude with some practical guidelines for using WFC3/IR to measure reliable SBF distances
PKCĪ“ Clustering at the Leading Edge and Mediating Growth Factor-Enhanced, but not ECM-Initiated, Dermal Fibroblast Migration
We have previously shown that the immobilized extracellular matrices (ECMs) initiate cell migration and soluble growth factors (GFs) further enhance ECM-initiated cell migration. GFs alone cannot initiate cell migration. To further investigate the specificity of the two signaling mechanisms, we focused on the protein kinase C (PKC) family genes in primary human dermal fibroblasts (DFs). We here show that platelet-derived growth factor-BB (PDGF-BB) strongly stimulates membrane translocation and leading edge clustering of protein kinase CĪ“ (PKCĪ“). In contrast, attachment to collagen matrix alone does not cause the translocation. Although the kinase function of PKCĪ“ is dispensable for initial membrane translocation, it is critical for its sustained presence at the cells's leading edge. Blockade of endogenous PKCĪ“ signaling with dominant-negative kinase-defective PKC (PKCĪ“-KD) or PKCĪ“-small interfering RNA (siRNA) completely inhibited PDGF-BB-stimulated DF migration. In contrast, neither PKCĪ“-KD nor PKCĪ“-siRNA affected collagen-induced initiation of DF migration. Overexpression of a constitutively activated PKCĪ“ (PKCĪ“-R144/145A) partially mimics the effect of PDGF-BB. However, PKCĪ“-KD, PKCĪ“-siRNA, or PKCĪ“-R144/145A does not affect PDGF-BB-stimulated activation of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase1/2, or c-Jun N-terminal kinase. Instead, inhibition of PKCĪ“ blocks PDGF-BB-stimulated activation of signal transducer and activator of transcription 3 (Stat3). This study unveiled the specificity of PKCĪ“ in the control of DF migration
NASTransfer: Analyzing Architecture Transferability in Large Scale Neural Architecture Search
Neural Architecture Search (NAS) is an open and challenging problem in
machine learning. While NAS offers great promise, the prohibitive computational
demand of most of the existing NAS methods makes it difficult to directly
search the architectures on large-scale tasks. The typical way of conducting
large scale NAS is to search for an architectural building block on a small
dataset (either using a proxy set from the large dataset or a completely
different small scale dataset) and then transfer the block to a larger dataset.
Despite a number of recent results that show the promise of transfer from proxy
datasets, a comprehensive evaluation of different NAS methods studying the
impact of different source datasets has not yet been addressed. In this work,
we propose to analyze the architecture transferability of different NAS methods
by performing a series of experiments on large scale benchmarks such as
ImageNet1K and ImageNet22K. We find that: (i) The size and domain of the proxy
set does not seem to influence architecture performance on the target dataset.
On average, transfer performance of architectures searched using completely
different small datasets (e.g., CIFAR10) perform similarly to the architectures
searched directly on proxy target datasets. However, design of proxy sets has
considerable impact on rankings of different NAS methods. (ii) While different
NAS methods show similar performance on a source dataset (e.g., CIFAR10), they
significantly differ on the transfer performance to a large dataset (e.g.,
ImageNet1K). (iii) Even on large datasets, random sampling baseline is very
competitive, but the choice of the appropriate combination of proxy set and
search strategy can provide significant improvement over it. We believe that
our extensive empirical analysis will prove useful for future design of NAS
algorithms.Comment: 19 pages, 19 Figures, 6 Table
Relations of Sex Hormone Levels to Leukocyte Telomere Length in Black, Hispanic, and Asian/Pacific Islander Postmenopausal Women
Background
Sex hormones may play important roles in sex-specific biological aging. We specifically examined the associations between circulating concentrations of sex hormones and leukocyte telomere length (TL).
Methods
We conducted a cross-sectional study of 1124 black, 444 Hispanic, and 289 Asian/Pacific Islander women in the Women's Health Initiative Observational Cohort. Concentrations of estradiol and testosterone were measured using electrochemiluminescence immunoassays. TL was measured using quantitative PCR.
Results
Women included in the study were 50 to 79 years of age. Levels of estradiol were not significantly associated with TL in this sample of women. The associations between total and free testosterone and TL differed by race/ethnicity (P for interactionā=ā0.03 for total testosterone and 0.05 for free testosterone). Total and free testosterone concentrations were not associated with TL in black and Hispanic women, whereas in Asian/Pacific Islanders, their concentrations were inversely associated with TL (P-trendā=ā0.003 for both). These associations appeared robust in multiple subgroup analysis and multivariable models adjusted for potential confounding factors. In Asian/Pacific Islanders, doubling of serum free testosterone concentration was associated with 202ābp shorter TL (95% CI, 51 to 353ābp), and doubling of total testosterone concentration was associated with 203ābp shorter TL (95% CI, 50 to 355ābp).
Conclusions
Serum concentration of estradiol was not associated with leukocyte TL in this large sample of postmenopausal women. Total and free testosterone levels were inversely associated with TL in Asian/Pacific Islander women but not in black and Hispanic women, although future studies to replicate our observations are warranted particularly to address potential ethnicity-specific relations.
The significant findings of the study
This study elucidates the potential roles of sex hormones in biological aging, and identified that total and free testosterone levels were inversely associated with telomere length in Asian/Pacific Islander women but not in black and Hispanic women.
The study adds
The findings of this study suggest that Asian/Pacific Islander women may be susceptible to the potential detrimental effects of high testosterone level on biologic aging
Action-derived molecular dynamics in the study of rare events
We present a practical method to generate classical trajectories with fixed
initial and final boundary conditions. Our method is based on the minimization
of a suitably defined discretized action. The method finds its most natural
application in the study of rare events. Its capabilities are illustrated by
non-trivial examples. The algorithm lends itself to straightforward
parallelization, and when combined with molecular dynamics (MD) it promises to
offer a powerful tool for the study of chemical reactions.Comment: 7 Pages, 4 Figures (3 in color), submitted to Phys. Rev. Let
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