Cumulative Density Distribution Research Articles

How ethnic name variations influence data linkage results: A population level study using public voter databases

ObjectivesIt has been shown that record linkage methods can induce bias in resulting datasets since the linkage quality may differ between ethno-racial groups. In this project, we used publicly available voter databases to investigate whether ethno-racial attributes can influence the similarities calculated using approximate string comparison functions on voters' names. ApproachWe used 11 annual snapshots of a publicly available US voter database between 2011 and 2021 with uniquely identifiable voter data. We extracted pairs of the same voter’s first and last name values from two consecutive snapshots where these values differ. We calculated string similarities and created similarity histograms for each of the available ethno-racial categories, and other sociodemographics variables such as gender and age. We characterized common patterns of name disagreements by ethno-racial groups and compared the shapes of these histograms using cumulative density distributions. Preliminary ResultsAcross the 10 snapshot pairs, eligible voters with non-missing first and last names are included (N2011/2012 = 6,193,001, N2020/2021 = 7,852,763), describing 124,009 first name changes and 485,807 last name changes. Results will be presented as a series of density plots. Using Jaro-Winkler similarity scores of 0.7, 0.8 and 0.9 as threshold, we examined whether match rates differ by ethno-racial categories. Conclusions and ImplicationsUsing the same string similarity function on names of individuals of different ethno-racial groups may lead to different distributions of the resulting similarity values. Understanding the patterns of ethno-racial-based name changes in your particular dataset is crucial on selecting linkage parameters that would minimise ethno-racial bias.

Impact structures on Mercury from MESSENGER data: Implications on their formation processes and crustal structure

In this study high-resolution stereo images and Digital Terrain Models (DTMs) from MErcury Surface, Space ENvironment, Geochemistry and Ranging (MESSENGER) mission were utilized to detect impact structures in regions not covered by Mercury’s Laser Altimeter (MLA), while gravitational data was utilized as a supported data set. We have established an inventory of 314 impact structures ≥150 km, classified on their morphological and gravitational characteristics. 24 basins ≥300 km have been newly discovered. Additionally, we have identified significant surface modifications in impact structures of smooth material infill, which can be either impact-induced or volcanic in origin. The Bouguer anomaly and crustal thinning in the center are displaying an interplay of predominant change of crustal structure in impact basins. Further, this study reveals a common impact history of Mercury and the Moon. Nevertheless, cumulative density distributions suggest the possibility of either a divergence in impactor populations responsible for forming large basins on both celestial bodies or a significant shift in impactor rates. This work holds important implications not only for understanding impact structure formation and evolution processes but also for interpreting the crustal structure. It presents an updated and expanded catalog of impact structures on Mercury, encompassing buried basins, and identifies new areas of interest, potentially serving as target sites for the forthcoming BepiColombo mission.

Eigenvalue Density, Li's Positivity, and the Critical Strip

We rewrite the zero-counting formula within the critical strip of the Riemann zeta function as a cumulative density distribution;this subsequently allows us to formally derive an integral expression for the Li coefficients associated with the Riemann Xi-function which, in particular, indicate that their positivity criterion is obeyed, whereby entailing the criticality of the non-trivial zeros. We conjecture the validity of this and related expressions without the need for the Riemann Hypothesis and also offer a physical interpretation of the result and discuss the Hilbert-Polya approach.

Surface Rupture and Slip Distribution along the Zheduotang Fault in the Kangding Section of the Xianshuihe Fault Zone

Abstract The Zheduotang fault (ZDTF) is located in the Kangding section of the Xianshuihe fault zone (XSHF). While the ZDTF plays an essential role in understanding the structural deformation pattern of the Kangding section. Little information is known about the paleoearthquake offsets and slip behavior of the ZDTF. It is therefore essential to analyze the seismic hazards in this area. Using UAV-based photogrammetry, high-resolution satellite images, and field observations, we mapped the surface trace of the fault in detail and measured the horizontal and vertical offsets geomorphological landforms along the fault. The binned cumulative offset probability density (COPD) distribution was calculated to analyze single-event and multievent cumulative offsets. We found that the ZDTF has scarps along its entire ~46 km length, and the offset distributions of its northwestern (NW) and southeastern (SE) sections feature different characteristics. The SE section follows a uniform slip model based on the relationship between cumulative and coseismic offsets. We estimated the maximum potential earthquake magnitudes of the NW section and SE section to be M6.6 and M7.0, respectively, from the measured offsets and empirical formulas. Finally, we discussed the seismic hazard of the ZDTF based on our findings and paleoearthquake data. The NW section is at risk of large earthquakes recurring in the future, whereas the SE section has a low risk of a >M7.0 earthquake recurring in the next 100 years. If these two sections rupture at the same event in the future, the maximum potential magnitude of the ZDTF is M7.2.

Economic analyses of onshore commercial large scale wind turbines installed in Turkey

In this study, the average wind conditions and economic analyses of four identical wind turbines of three-bladed and 3 MW of rated power located in an installed wind farm abbreviated as WTPP and found in Eastern Mediterranean region of Turkey in Hatay province, were conducted. In this way, the probability density distributions based on wind directions regarding these identical wind turbines of the wind farm as well as cumulative probability density distributions regarding wind speeds for all identical wind turbines were performed. Besides, the economic analysis in terms of the present value calculation for a 3 MW rated power wind turbine was executed, in which the results demonstrated that the application of the wind turbine project of this type would be profitable.

Prenatal Multivitamin Use and MTHFR Genotype Are Associated with Newborn Cord Blood DNA Methylation.

Background: Fetal development involves cellular differentiation and epigenetic changes—complex processes that are sensitive to environmental factors. Maternal nutrient levels during pregnancy affect development, and methylene tetrahydrofolate reductase (MTHFR) is important for processing the nutrient folate. Hypothesis: We hypothesize that supplement intake before pregnancy and maternal genotype are associated with DNA methylation in newborns. Methods: In the pregnancy cohort, Early Autism Risk Longitudinal Investigation (EARLI), health history, and genotype information was obtained (n = 249 families). Cord blood DNA methylation (n = 130) was measured using the Illumina HumanMethylation450k array and global DNA methylation levels were computed over 455,698 sites. Supplement use preconception and during pregnancy were surveyed at visits during pregnancy. We evaluated associations between maternal preconception supplement intake and global DNA methylation or DNA methylation density distributions of newborn cord blood, stratified by the presence of a variant maternal MTHFR C677T allele. Results: Maternal preconceptional multivitamin intake was associated with cord blood methylation, dependent on maternal MTHFR genotype (interaction term p = 0.013). For mothers without the MTHFR variant allele, multivitamin intake was associated with 0.96% (95% CI: 0.09, 1.83) higher global cord blood methylation (p = 0.04) and was also associated with the cumulative density distribution of methylation (p = 0.03). For mothers with at least one variant allele, multivitamin intake had a null −0.06% (95% CI: −0.45, 0.33) association with global cord blood DNA methylation, and was not associated with the cumulative density distribution (p = 0.37). Conclusions: We observed that cord blood DNA methylation was associated with maternal supplement exposure preconception and maternal genotype. Genetic context should be considered when assessing DNA methylation effects of modifiable risk factors around the time of pregnancy.

METHOD OF DISTRIBUTIONS FOR SYSTEMS WITH STOCHASTIC FORCING

The method of distributions is developed for systems that are governed by hyperbolic conservation laws with stochastic forcing. The method yields a deterministic equation for the cumulative density distribution (CDF) of a system state, e.g., for flow velocity governed by an inviscid Burgers' equation with random source coefficients. This is achieved without recourse to any closure approximation. The CDF model is verified against MC simulations using spectral numerical approximations. It is shown that the CDF model accurately predicts the mean and standard deviation for Gaussian, normal and beta distributions of the random coefficients.

An integrated workflow for fracture characterization in chalk reservoirs, applied to the Kraka Field

Abstract Oil and gas production of tight chalk reservoirs frequently rely on the presence of natural fractures, which increases the effective permeability of the reservoirs. Fracture characterization is therefore imperative in optimizing production schemes and obtaining economically viable recovery factors. Subsurface fracture characterization is often deemed challenging as the available data is typically of varying age and quality, and represents different scales. We have developed an integrated workflow for fracture characterization in chalk to address these challenges. The workflow is based on data from borehole images, cores and seismic. These data are typically available for most chalk (and hydrocarbon) fields. The interpreted borehole image dataset contains over 17 000 manual dip picks, ensuring a statistically viable base. A total of 150 m of core is available from 3 wells. The applied 3D seismic cube covers an 8 × 5 km hydrocarbon chalk field in the Danish North Sea. In this workflow, the scale-gap between the data sets is bridged by the introduction of two ant-tracked attribute volumes, which display structural trends below the resolution of amplitude seismic. Further insight into the intricacy of subsurface fracture systems is obtained from fracture density logs, which provide an opportunity to study spatial distribution of fractures as well as a qualitative measure of fracture clustering. Cumulative density distribution plots and calculation of the variation coefficient of fracture spacing provide a more quantitative analysis of the fracture distribution. The workflow, presented here in a step-by-step manner, is a general approach applied to data from the Kraka Field of the Danish North Sea. In the Kraka Field, the usage of this integrated approach shows that the fracture pattern in this region is more complex than previously suggested; probably controlled by the regional maximum horizontal stress and salt movements.

Mathematical Description of Rooting Profiles of Agricultural Crops and its Effect on Transpiration Prediction by a Hydrological Model

The geometry of rooting systems is important for modeling water flows in the soil-plant-atmosphere continuum. Measured information about root density can be summarized in adjustable equations applied in hydrological models. We present such descriptive functions used to model root density distribution over depth and evaluate their quality of fit to measured crop root density profiles retrieved from the literature. An equation is presented to calculate the mean root half-distance as a function of depth from root length density profiles as used in single root models for water uptake. To assess the importance of the shape of the root length density profile in hydrological modeling, the sensitivity of actual transpiration predictions of a hydrological model to the shape of root length density profiles is analyzed using 38 years of meteorological data from Southeast Brazil. The cumulative root density distributions covering the most important agricultural crops (in terms of area) were found to be well described by the logistic function or the Gompertz function. Root length density distribution has a consistent effect on relative transpiration, hence on relative yield, but the common approach to predict transpiration reduction and irrigation requirement from soil water storage or average water content is shown to be only partially supported by simulation results.

Nonparametric Bayesian-based recognition of solar irradiance conditions: Application to the generation of high temporal resolution synthetic solar irradiance data

High resolution synthetic irradiance is of interest for theoretical studies such as grid integration of solar PV and battery storage analysis. Access to site-specific data is often limited to inadequate temporal resolutions for such application. A new model for producing synthetic solar global horizontal irradiance (GHI) time-series at up to 1-min resolution is presented as derived from >10-min input data. Briefly, it is a clustered-based method for daily clearness index distributions using Dirichlet process Gaussian mixture model (DPGMM). DPGMM is a nonparametric Bayesian (NPB) model indexed with an infinite-dimensional space of parameters. The key benefit of the NPB paradigm is the automatic adaptation to the correct complexity level and model size, suggesting a local adaptation of the model to all climatic conditions. A posterior inference using Markov chain Monte Carlo algorithm (namely Gibbs sampling) is applied. The model only requires a valid number of intraday data to construct daily distributions, then it can be applied worldwide. The synthetic GHI time series are validated against observed 1-min GHI data for four locations distributed throughout the world with different climatic conditions and significant geographic separation. Moreover, the presented method can generate data based on similar climatic conditions. A good fit between real and generated data is observed. We present an nRMSE ≤4% and nMBE <±4% between generated and measured means at both daily and monthly scales for all sites. The agreement between the real and generated cumulative density distributions of six comparative variability metrics (defined in text) at four different sites is measured using the overlapping and the Kullback–Leibler coefficients, which are ≥75% and ≤10% respectively, in all cases. To ensure the reproducibility of the research presented in this paper, the methodology is freely available as an R-package downloadable from SolarClusGnr.

Impact of transmission techniques in asymmetric RF/FSO system over Nakagami‐m and gamma‐gamma fading channels with pointing errors

SummaryIn this paper, the performance of transmission techniques on the fixed‐gain amplify‐and‐forward–based asymmetric radio frequency/free space optical (RF/FSO) communication system is studied. The RF link and FSO link are, respectively, modeled by the Nakagami‐m and Gamma‐Gamma fading channels under the effect of zero boresight and non‐zero boresight pointing errors subject to heterodyne detection. Maximum ratio transmission (MRT) and orthogonal space‐time block coding (OSTBC) techniques are the transmission scenarios considered at the system source while selection combining is used for reception at the relay and destination for the signal detection. Moreover, a unified cumulative density distribution (CDF) of end‐to‐end signal‐to‐noise ratio is derived for the system. By utilizing this channel statistical CDF, the closed‐form expressions for the outage probability and average bit error rate for the M‐ary phase shift keying modulation are then obtained for the system. The analysis presented illustrates that both the atmospheric turbulence and pointing error significantly degrade the system performance. Based on this, the MRT transmission technique offers a better performance compared with the OSTBC techniques under the same system conditions. The accuracy of the analytical results is verified by Monte‐Carlo simulations.

Surface rupture and slip distribution along the Lenglongling fault in the NE Tibetan Plateau: Implications for faulting behavior

The Lenglongling Fault (LLLF) is located in the western section of the “Tianzhu seismic gap” along the Qilian-Haiyuan fault zone in the NE Tibetan Plateau, between the 1920 M8.5 Haiyuan and the 1927 M8.0 Gulang earthquakes. There is little information about the paleoseismic history of the LLLF and understanding the faulting history of the LLLF is important for determining the seismic hazards of both the fault and the seismic gap. Using UAV-based photogrammetry, high-resolution satellite imagery, and field investigations, we mapped the surface trace of the fault in detail and measured 192 left-lateral offsets of geomorphic markers along the fault trace. A binned cumulative offset probability density (COPD) distribution was calculated to analyze single-event and multi-event cumulative offsets. As a result, we find that the LLLF has fresh scarps along the entire ∼120 km length, indicating that the most recent event might have ruptured the full-segment of the fault. The coseismic offset of the most recent event changes along the fault trace and has an asymmetrical bell-shaped distribution. The maximum offset was ∼7 m, located in the middle-eastern section of the fault, and the offset decreases progressively towards both ends. The minimum offset, located at the western end, was ∼3.0 m, and the average coseismic offset was ∼4.8 m. The cumulative offsets of the four most recent paleoearthquakes are multiples of the coseismic offset of the most recent event, and show similar slip distributions, indicating that the fault ruptures with a characteristic slip. The fault slip distribution, estimated recurrence interval, and estimated moment magnitude imply that the LLLF releases accumulated strain energy mainly by repeatedly producing Mw 7.5–7.8 earthquakes every 1000 ± 200 years. We also show that the binned COPD technique performs well to separate single-event and multi-event cumulative offsets.

Deconvolution of fractionation data to deduce consistent washability and partition curves for a mineral separator

A density partition curve for a hypothetical steady-state separator is applied to a known feed density distribution to give the density distributions of the product and reject. Density fractionation of each of these streams is then simulated, with the fractionator Ecarte Probable, EpX, set at a specific level, to produce a set of seven or more fractions of varying mass and increasing average density. This study then describes a new algorithm that attempts to recover the partition curve of the original steady-state separator, using only the three sets of limited fractionation data and the assumption that the form of the partition curve equation is known. The algorithm first uses a simple interpolation rule to convert each set of fractionation data into a cumulative density distribution. Then the feed density distribution and the partition curve parameters are simultaneously adjusted until a consistent set of feed, product and reject density distributions is found with minimum variation from the raw fractionation data. The algorithm was applied to a simple rectangular feed distribution, and then a more realistic distribution. In both cases the algorithm accurately determined the density cut point (D50) of the separator, even for poor quality fractionations. The accuracy of the determined separator Ep value depended on the fractionator EpX and the amount of near-density material. For the simple rectangular distribution, the algorithm under predicted the separator Ep, with the error being about 34% of the fractionator EpX. For the more realistic feed distribution, there was more scatter in the Ep values, but still the same general trend. The error increased when there was little near-density material. Increasing the number of flow fractions from 7 to 11 brought some improvement in accuracy. However, above 11 fractions there was no further significant improvement. Expressing the partition function in terms of D75 and D25 (instead of D50 and Ep) reduced the sensitivity of the algorithm to the initial guess values.

Extrapolating wind data at high altitudes with high precision methods for accurate evaluation of wind power density, case study: Center of Iran

With growing wind turbine sizes and increasing demands for electricity, it is important to determine accurately wind shear profile, up to high altitudes, for large scale wind turbine installation. The installed wind turbine towers in Iran have hardly exceeded the height of 40 m. In this study, the effectiveness of different extrapolation methods are investigated to determine robustly wind speed and wind power density at higher altitudes. As a case study, wind data was collected from the center of Iran which consists of 35 wind stations in nine provinces. For precise evaluation, the wind speed data were recorded based on 10-min average at various heights ranging from 10 m to 100 m and the wind power potential was obtained on both seasonally and daily basis. The widely used Weibull distribution function is selected for which the shape factor and scale parameter are determined using the standard deviation method, the empirical method of Lysen and the power density method at different heights. From the extrapolated wind data, the mean wind speed, wind power density, optimal wind speed, probability and cumulative density distributions are obtained and the geographic information systems maps are produced and discussed. The results indicate that the power density method is the most accurate method for extrapolating wind characteristics. From the results, it is also observed that variation of power density with time is significant. In period I (spring and summer), most parts of the center of Iran have significant potential for installing large scale wind turbines. However in period II (fall and winter), the amount of wind power density decreases considerably. In overall, the north western and north eastern parts of the center of Iran are recommended for large scale wind turbine installation. The methodology discussed here can be equally employed for extrapolating of wind speeds data at any heights within any geographical region.

A Search for Fast Radio Bursts with the GBNCC Pulsar Survey

Abstract We report on a search for fast radio bursts (FRBs) with the Green Bank Northern Celestial Cap (GBNCC) Pulsar Survey at 350 MHz. Pointings amounting to a total on-sky time of 61 days were searched to a dispersion measure (DM) of 3000 pc cm−3, while the rest (23 days; 29% of the total time) were searched to a DM of 500 pc cm−3. No FRBs were detected in the pointings observed through 2016 May. We estimate a 95% confidence upper limit on the FRB rate of FRBs sky−1 day−1 above a peak flux density of 0.63 Jy at 350 MHz for an intrinsic pulse width of 5 ms. We place constraints on the spectral index α by running simulations for different astrophysical scenarios and cumulative flux density distributions. The nondetection with GBNCC is consistent with the 1.4 GHz rate reported for the Parkes surveys for α &gt; +0.35 in the absence of scattering and free–free absorption and α &gt; −0.3 in the presence of scattering, for a Euclidean flux distribution. The constraints imply that FRBs exhibit either a flat spectrum or a spectral turnover at frequencies above 400 MHz. These constraints also allow estimation of the number of bursts that can be detected with current and upcoming surveys. We predict that CHIME may detect anywhere from several to ∼50 FRBs per day (depending on model assumptions), making it well suited for interesting constraints on spectral index, the log N–log S slope, and pulse profile evolution across its bandwidth (400–800 MHz).

High-Fidelity Modeling and Simulation for a High Flux Isotope Reactor Low-Enriched Uranium Core Design

A high-fidelity model of the High Flux Isotope Reactor (HFIR) with a low-enriched uranium (LEU) fuel design and a representative experiment loading has been developed to serve as a new reference model for LEU conversion studies. With the exception of the fuel elements, this HFIR LEU model is completely consistent with the current highly enriched uranium HFIR model. Results obtained with the new LEU model provide a baseline for analysis of alternate LEU fuel designs and further optimization studies.The newly developed HFIR LEU model has an explicit representation of the HFIR-specific involute fuel plate geometry, including the within-plate fuel meat contouring, and a detailed geometry model of the fuel element side plates. Such high-fidelity models are necessary to accurately account for the self-shielding from 238U and the depletion of absorber materials present in the side plates. In addition, a method was developed to account for fuel swelling in the high-density LEU fuel plates during the depletion simulation. Calculated time-dependent metrics for the HFIR LEU model include fission rate and cumulative fission density distributions, flux and reaction rates for relevant experiment locations, point kinetics data, and reactivity coefficients.

Influence of shockwave profile on ejecta from shocked Pb surface: Atomistic calculations**Project supported by the National Natural Science Foundation of China (Grant Nos. 11472254 and 11272006).

We conduct molecular dynamics simulations of the ejection process from a grooved Pb surface subjected to supported and unsupported shock waves with various shock-breakout pressures (PSB) inducing a solid–liquid phase transition upon shock or release. It is found that the total ejecta mass changing with PSB under a supported shock reveals a similar trend with that under an unsupported shock and the former is always less than the latter at the same PSB. The origin of such a discrepancy could be unraveled that for an unsupported shock, a larger velocity difference between the jet tip and its bottom at an early stage of jet formation results in more serious damage, and therefore a greater amount of ejected particles are produced. The cumulative areal density distributions also display the discrepancy. In addition, we discuss the difference of these simulated results compared to the experimental findings.

AN HST/COS SURVEY OF THE LOW-REDSHIFT INTERGALACTIC MEDIUM. I. SURVEY, METHODOLOGY, AND OVERALL RESULTS*

ABSTRACT We use high-quality, medium-resolution Hubble Space Telescope/Cosmic Origins Spectrograph (HST/COS) observations of 82 UV-bright active galactic nuclei (AGNs) at redshifts z AGN &lt; 0.85 to construct the largest survey of the low-redshift intergalactic medium (IGM) to date: 5138 individual extragalactic absorption lines in H i and 25 different metal-ion species grouped into 2611 distinct redshift systems at z abs &lt; 0.75 covering total redshift pathlengths Δz H i = 21.7 and Δz O vi = 14.5. Our semi-automated line-finding and measurement technique renders the catalog as objectively defined as possible. The cumulative column density distribution of H i systems can be parametrized d &#x0E23A; ( &gt; N ) / dz ?> = C 14 ( N / 10 14 cm &minus; 2 ) &minus; ( &beta; &minus; 1 ) ?> , with C 14 = 25 ± 1 and β = 1.65 ± 0.02. This distribution is seen to evolve both in amplitude, C 14 &prop; ( 1 &plus; z ) 2.3 &PlusMinus; 0.1 ?> , and slope β(z) = 1.75–0.31 z for z ≤ 0.47. We observe metal lines in 418 systems, and find that the fraction of IGM absorbers detected in metals is strongly dependent on N H I ?> . The distribution of O vi absorbers appears to evolve in the same sense as the Lyα forest. We calculate contributions to Ω b from different components of the low-z IGM and determine the Lyα decrement as a function of redshift. IGM absorbers are analyzed via a two-point correlation function in velocity space. We find substantial clustering of H i absorbers on scales of Δv = 50–300 km s−1 with no significant clustering at Δv ≳ 1000 km s−1. Splitting the sample into strong and weak absorbers, we see that most of the clustering occurs in strong, N H i ≳ 1013.5 cm−2, metal-bearing IGM systems. The full catalog of absorption lines and fully reduced spectra is available via the Mikulski Archive for Space Telescopes (MAST) as a high-level science product at http://archive.stsci.edu/prepds/igm/.

TOBAE: A Density-based Agglomerative Clustering Algorithm

This paper presents a novel density based agglomerative clustering algorithm named TOBAE which is a parameter-less algorithm and automatically filters noise. It finds the appropriate number of clusters while giving a competitive running time. TOBAE works by tracking the cumulative density distribution of the data points on a grid and only requires the original data set as input. The clustering problem is solved by automatically finding the optimal density threshold for the clusters. It is applicable to any N-dimensional data set which makes it highly relevant for real world scenarios. The algorithm outperforms state of the art clustering algorithms by the additional feature of automatic noise filtration around clusters. The concept behind the algorithm is explained using the analogy of puddles ('tobae'), which the algorithm is inspired from. This paper provides a detailed algorithm for TOBAE along with the complexity analysis for both time and space. We show experimental results against known data sets and show how TOBAE competes with the best algorithms in the field while providing its own set of advantages.

General partially linear additive transformation model with right-censored data

We propose a class of general partially linear additive transformation models (GPLATM) with right-censored survival data in this work. The class of models are flexible enough to cover many commonly used parametric and nonparametric survival analysis models as its special cases. Based on the B spline interpolation technique, we estimate the unknown regression parameters and functions by the maximum marginal likelihood estimation method. One important feature of the estimation procedure is that it does not need the baseline and censoring cumulative density distributions. Some numerical studies illustrate that this procedure can work very well for the moderate sample size.