484 research outputs found

    A Secure Federated Data-Driven Evolutionary Multi-objective Optimization Algorithm

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    Data-driven evolutionary algorithms usually aim to exploit the information behind a limited amount of data to perform optimization, which have proved to be successful in solving many complex real-world optimization problems. However, most data-driven evolutionary algorithms are centralized, causing privacy and security concerns. Existing federated Bayesian algorithms and data-driven evolutionary algorithms mainly protect the raw data on each client. To address this issue, this paper proposes a secure federated data-driven evolutionary multi-objective optimization algorithm to protect both the raw data and the newly infilled solutions obtained by optimizing the acquisition function conducted on the server. We select the query points on a randomly selected client at each round of surrogate update by calculating the acquisition function values of the unobserved points on this client, thereby reducing the risk of leaking the information about the solution to be sampled. In addition, since the predicted objective values of each client may contain sensitive information, we mask the objective values with Diffie-Hellmann-based noise, and then send only the masked objective values of other clients to the selected client via the server. Since the calculation of the acquisition function also requires both the predicted objective value and the uncertainty of the prediction, the predicted mean objective and uncertainty are normalized to reduce the influence of noise. Experimental results on a set of widely used multi-objective optimization benchmarks show that the proposed algorithm can protect privacy and enhance security with only negligible sacrifice in the performance of federated data-driven evolutionary optimization.Comment: This paper has been accepted by IEEE Transactions on Emerging Topics in Computational Intelligence journa

    An Ice-Core Proxy for Antarctic Circumpolar Zonal Wind Intensity

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    Using US National Centers for Environmental Prediction/US National Center for Atmospheric Research re-analysis data, we investigate the relationships between crustal ion (nssCa(2+)) concentrations from three West Antarctic ice cores, namely, Siple Dome (SD), ITASE00-1 (IT001) and ITASE01-5 (IT015), and primary components of the climate system, namely, air pressure/geopotential height, zonal (u) and meridional (v) wind strength. Linear correlation analyses between nssCa(2+) concentrations and both air-pressure and wind fields for the period of overlap between records indicate that the SD nssCa(2+) variation is positively correlated with spring circumpolar zonal wind, while IT001 nssCa(2+) has a positive correlation with circumpolar zonal wind throughout the year (r \u3e 0.3, p \u3c 0.01). Intensified Southern Westerlies circulation is conducive to transport of more crustal aerosols to both sites. Further correlation analyses between nssCa(2+) concentrations from SD and IT001 and atmospheric circulation suggest that the high inland plateau (represented by core IT001) is largely influenced by transport from the upper troposphere. IT015 nssCa(2+) is negatively correlated with westerly wind in October and November, suggesting that stronger westerly circulation may weaken the transport of crustal species to IT015. Correlations of nssCa(2+) from the three ice cores with the Antarctic Oscillation index are consistent with results developed from the wind-field investigation. In addition, calibration between nssCa(2+) concentration and the multivariate El Nino-Southern Oscillation (ENSO) index shows that crustal species transport to IT001 is enhanced during strong ENSO events

    Doubly resonant photonic crystal cavity using merged bound states in the continuum

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    In this work, a doubly resonant photonic crystal (PhC) cavity using the merged bound states in the continuum (BICs) is proposed to obtain a higher second harmonic generation (SHG) efficiency. Firstly by scanning geometry parameters the accidental BICs and a band-edge mode outside the light cone can be obtained. Then as the lattice constant or the thickness of the slab is adjusted the accidental BICs will merge. A supercell with large and small holes is constructed and the band-edge mode outside the light cone can be mode-matched with the merged BICs mode. Finally the heterostructure PhC cavity is designed. The merged BICs show a high quality factor for the photonic crystal with finite size. Consequently, the SHG efficiency of the lattice constant near merged BICs of ~6000% W-1 is higher than the one of the isolated BIC

    PO-289 Lipidomic analysis of blood serum from prepubertal boys with different BMI

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    Objective Childhood obesity is a worldwide health problem which may causes metabolic diseases such as hyperglycemia, hyperlipidemia, hypertension and hyperuricemia. It is well know that lipid metabolites regulate fatty acid and glucose homeostasis. Lipidomics is the comprehensive analysis of lipid metabolites which include their quantitation and metabolic pathways. The intention of this study is to identify the circulating lipid species which are altered in obese prepubertal boys. Methods A total number of 72 boys aged 10.28 ±0.69 years old were included into this study, and divided into normal(NC), overweight(OW) and obese group(OB). The degree of maturation of all boys were measured by bone age and sex hormones. Then we measured the form indexes, blood lipids, blood glucose level to identify the current state of all boys. Serum indexes were detected by CLIA and ELISA methods. A lipidomic method was established by using a Waters Acquity UPLCI-Class liquid system combined with Waters Xevo G2-SQ-TOF mass spectrometry system. The identification and analysis of lipid metabolites were complished by using MassLynx 4.1, Progenesis QI software and LipidMaps database. Statistical analyzes were performed using SPSS22.0 software. Results (1)The waist-to-hip ratio, bone age and HDL-c levels ware significant lower in OW and OB groups. The TG level was significant higner in OB group. The DHEA and SHBG levels was significant higner in OW and OB groups and the other sex hormones are not . (2) In this study, 153 most significant different lipid metabolites were founded, incluing 3 diacylglycerol, 32 triglyceride, 1 Phosphatidyl cholines, 1 Phosphatidylinositol, 3 Sphingomyelin, 1 Ceramide which significant higher in OW&OB group; 4 diacylglycerol, 17 Phosphatidic acid, 32 Phosphatidyl cholines, 4 Phosphatidylinositol, 13 Phosphatidylserine, 18 Phosphatidyl ethanolamine, 3 Phosphoglycerides, 13 Sphingomyelin and 6 Ceramide which significant lower in OW&OB group. Among all this metabolites, 8 lipids (fold change ≥5) were founded as the significant biomarkers related prepubertal obesity , including 1 Phosphatidyl cholines, 1 phosphatidylserine, 2 sphingomyelin and 4 Triglyceride. What’s more, the level of SM(d16:1/24:0) and TG(15:0/17:1/20:3) which measured by UPLC-QTOF/MS are highly positive correlated with the level of serum SHBG; PC(18:0/0:0) and TG(16:1/18:0/20:3) are highly negtive correlated with serum SHBG. Conclusions Overweight and obese prepubertal boys showed disorder in lipid metabolism and bone growth. The lipidomic results showed lower SHBG level is related with the disorder of lipid metabolism. We suggest that further studies on these metabolites could help us gain a better understanding of the relationship between obesity and growth disorder

    Sea Level Pressure Variability Over the Southern Indian Ocean Inferred from a Glaciochemical Record in Princess Elizabeth Land, East Antarctica

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    A 250-year, high-resolution, multivariate ice core record from LGB65 (70degrees50\u2707 S, 77degrees04\u2729 E; 1850 m asl), Princess Elizabeth Land (PEL), is used to investigate sea level pressure (SLP) variability over the southern Indian Ocean (SIO). Empirical orthogonal function (EOF) analysis reveals that the first EOF (EOF1) of the glaciochemical record from LGB65 represents most of the variability in sea salt throughout the 250-year record. EOF1 is negatively correlated (95% confidence level and higher) to instrumental mean sea level pressure (MSLP) at Kerguelen and New Amsterdam islands, SIO. On the basis of comparison with NCEP/NCAR reanalysis, strong correlations were found between sea-salt variations and a quasi-stationary low that lies to the north of Prydz Bay, SIO. Comparison with a 250-year-long summer transpolar index (STPI) inferred from sub-Antarctic tree ring records reveals strong coherency. Decadal-scale SLP variability over SIO suggests shifting of the polar vortex. Prominent decadal-scale deepening of the southern Indian Ocean low (SIOL) exists circa 1790, 1810, 1835, 1860, 1880, 1900, and 1940 A. D., continuously after the 1970s, and prominent weakening circa 1750, 1795, 1825, 1850, 1870, 1890, 1910, and 1955 A. D. The LGB65 sea-salt record is characterized by significant decadal-scale variability with a strong similar to21-year periodic structure (99.9% confidence level). The relationship between LGB65 sea salt and solar irradiance changes shows that this periodicity is possibly the solar Hale cycle ( 22 years)

    Impaired Sensorimotor Integration in Restless Legs Syndrome

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    Objective: Restless legs syndrome (RLS) is a complicated sensorimotor syndrome that may be linked to changes in sensorimotor integration. The mechanism of such changes is unclear. The aim of this study was to investigate sensorimotor integration in patients with RLS through transcranial magnetic stimulation-motor evoked potentials (TMS-MEPs) preceded by peripheral electric stimulation.Methods: Fourteen RLS patients and 12 healthy, age-matched controls were investigated. The clinical severity of RLS was evaluated based on the International Criteria of the International Restless Legs Syndrome Study Group (IRLSSG) severity scores. The tibial and median H-reflexes and the resting motor threshold (RMT) of the abductor pollicis brevis (APB) were tested in all 26 subjects. The RMT of the tibialis anterior (TA) was tested in 8 patients and 7 controls. All 26 subjects underwent measurement of unconditioned MEPs of the APB. Electric pulses were applied to the right median nerve, followed by TMS pulses over the left motor cortex at interstimulus intervals (ISIs) of 20, 25, 30, 50, 100, 150, and 200 ms. Unconditioned MEPs of the TA were measured in 8 patients and 7 controls. Electric pulses were applied to the right peroneal nerve, followed by TMS pulses over the left motor cortex at ISIs of 30, 35, 45, 60, 100, and 200 ms. The degree of modulation of MEPs by electric stimulation was expressed as the ratio of the conditioned MEP amplitude to the unconditioned MEP amplitude. Ratios <1 indicated inhibition, and ratios >1 indicated facilitation.Results: No significant differences in RMT or H-reflex latencies or amplitudes were found between RLS patients and controls. A significant increase in unconditioned MEP amplitudes of the TA was observed in patients compared to controls (p = 0.03). Long-latency afferent inhibition (LAI) of the median nerve in RLS patients was decreased significantly at ISIs of 150 (p = 0.000) and 200 ms (p = 0.004). Upon peroneal nerve stimulation, no significant difference was observed between the two groups at any ISI.Conclusions: Our results suggest increased motor cortical excitability of the legs and disturbed sensorimotor integration in RLS patients; this disturbance might originate at the cortical level

    Quasi-phase-matching with Spontaneous Domain Inversion in an Integrated Lithium Niobate Micro-racetrack Resonator

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    Quasi-phase-matching (QPM) technology is the most popular and significant method to achieve efficient nonlinear frequency conversion. The realization of periodically poling to achieve QPM in photonic integrated circuits (PICs) is a challenging issue for the requirement of CMOS compatible and large-scale fabrication. Here we realize a spontaneous periodical domain inversion without poling but by dispersion engineering and designing the orientation of the crystal due to the circular propagation of light waves in an integrated lithium niobate micro-racetrack resonator (MRR). The QPM second harmonic generation (SHG) with a normalized conversion efficiency of 2.25%\%/W (169th-order QPM) has been achieved in the high-quality factor resonator of ∼108 \sim 10^{8} with the straight waveguide (TE00_{00} mode) of ultra-low propagation loss of 0.0022dB/cm. The efficiency can be further enhanced by using a first-order QPM, and the bandwidth can be made broader by employing a shorter interaction length for photonics and quantum optics. The configurable spontaneous quasi-phase-matching lithium niobate MRR on X-cut thin-film lithium niobate on insulator (LNOI) provides a significant on-chip integrated platform for other optical parametric processes

    The Xiaoyangqiao section, Dayangcha, North China: the new global Auxiliary Boundary Stratotype Section and Point (ASSP) for the base of the Ordovician System

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    In 2019 the Sub-Commission on the Ordovician System approved the Xiaoyangqiao section, North China as a new ASSP section for the base of the Ordovician System. The sedimentary succession of the section is exposed in a natural outcrop near the Dayangcha Village at a position of 42°3'24''N, 126°42'21''E. It has a well-preserved, abundant and diverse fossil record across the boundary with key markers (conodonts and graptolites), which provide improved intercontinental correlation of the Cambrian– Ordovician boundary. The appearance of the first planktonic graptolites is immediately below the base of the Cordylodus lindstromi Conodont Zone. Other fossils, including acritarchs, brachiopods and trilobites are also present in the Xiaoyangqiao ASSP section. Non-biotic secondary global markers near the base of the Ordovician System include a positive carbon isotopic excursion with the maximum peak (named HSS) below the boundary, a prominent unnamed negative peak immediately below the boundary and a prominent carbon isotope excursion with positive peaks above the boundary. The latter excursion is associated with the appearance of the planktonic graptolites in the Ordovician. The strength of the Xiaoyangqiao ASSP section is the correlation between the conodonts and graptolites, correspondence of sea-level lowstands, and the matches of geochemical parameters

    The impact of an abandoned mercury mine on the environment in the Xiushan region, Chongqing, southwestern China

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    Mercury contamination is a serious problem in the Hg mining area of Xiushan County, Chongqing, southwestern China. The concentrations of total mercury (THg) and methylmercury (MeHg) in paddy soil, surface water, and rice (grain) samples were determined to investigate the regional distribution of Hg contamination. Simultaneously, gaseous elemental Hg (GEM) in ambient air near the sampling sites was measured. The total Hg concentrations in surface water were highly elevated, ranging from 13 to 2390 ng/L, and the total MeHg concentrations varied between 0.17 and 1.1 ng/L. The dissolved Hg and MeHg concentrations in surface water ranged from 4.7 to 470 ng/L and 0.14–0.35 ng/L, respectively. High THg and MeHg concentrations were also obtained in paddy soils from mining areas, ranging from 0.45 to 68 μg/g and 0.13–4.8 ng/g, respectively. Similar to the high concentrations in water and soil, the THg concentration in rice (grain) ranged from 4.7 to 550 ng/g and MeHg from 2.9 to 26 ng/g. Elevated Hg concentrations in rice, as a staple food of local residents, confirmed that rice consumption could be a vital pathway for MeHg exposure to native people. Humic acid and fulvic acid had significant correlations with soil MeHg, implying that they have important roles that influence MeHg production in soil. The spatial distribution characteristics of Hg and MeHg pollution in the local environment indicated their origins from historic Hg mining sites in the Xiushan area.acceptedVersio
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