Uniform Model Research Articles

Visualization of simulated coating efficiency and uniformity.

For a line-of-sight coating uniformity model, the source distribution is normalized such that all material can be traced. This is validated for a point source in an empty coating chamber. We can now quantify the source utilization of a coating geometry to determine what fraction of the evaporated source material is collected on the optics of interest. For the example of a planetary motion system, we calculate this utilization and two nonuniformity parameters for a large range of two input parameters, here the distance between the source and the rotary drive system and the lateral displacement of the source from the machine centerline. Contour plot visualizations in this 2D parameter space assist understanding geometry trade-offs.

Energy system transition pathways to meet the global electricity demand for ambitious climate targets and cost competitiveness

This study presents a novel energy system modelling approach for the analysis and comparison of global energy transition pathways for the decarbonisation of the electricity sector. The results of the International Energy Agency (IEA), and the Teske/DLR scenarios are each reproduced. Additionally, five new energy transition trajectories, called LUT, are presented. The research examines the feasibility of each scenario across nine major regions in 5-year intervals, from 2015 to 2050, under a uniform modelling environment with identical technical and financial assumptions. The main differences between the energy transition paths are identified across: (1) the average electricity generation costs; (2) energy diversity; (3) system flexibility; (4) energy security; and, (5) transition dynamics. All LUT and Teske/DLR scenarios are transitioned to zero CO2 emissions and a 100% renewable energy system by 2050 at the latest. Results reveal that the LUT scenarios are the least-cost pathways, while the Teske/DLR scenarios are centred around energy diversity with slightly higher LCOE of around 10–20%. The IEA shares similarities with the Teske/DLR scenarios in terms of energy diversity yet depends on the continued use of fossil fuels with carbon capture and storage, and nuclear power. The IEA scenario based on current governmental policies presents a worst-case situation regarding CO2 emissions reduction, climate change and overall system costs.

Astrometric observations of water maser sources toward the Galactic Center with VLBI

AbstractThe Central Molecular Zone (CMZ) in the Galactic Center region shows outstanding non-circular motion unlike the Galactic disk. While several models describing this non-circular motion have been proposed, a uniform kinematic model of the CMZ orbit has not yet emerged. To uncover the dynamics of the Galactic center region, we conducted VLBI astrometric observations of 22GHz water maser sources towards the Galactic center using VERA. By measuring parallaxes and proper motions, we can determine whether each source is actually located in the CMZ or not, and identify the three-dimensional positions and velocities in the non-circular orbit if the source is indeed located in the CMZ. We present the results of our astrometric study for several maser sources associated with molecular clouds towards the Galactic center. The astrometric observations toward Sgr B2(M) indicated that Sgr B2 complex is moving toward the positive Galactic longitude relative to Sgr A*.

Ground Motion Models for Non-Spectral Intensity Measures Based on the Iranian Database

ABSTRACT An Iranian earthquake database has been employed to propose local empirical equations to predict non-spectral ground motion intensity measures, including Arias intensity, cumulative absolute velocity and duration of ground motions. The significant duration models have been considered 5% – 75% and 5% – 95% of Arias intensity in analyses. The bracketed and uniform duration models were proposed for absolute or relative acceleration thresholds, including 0.025g, 0.05g, 0.1g 0.025PGA, 0.05PGA and 0.1PGA. In this study, we used an updated dataset consisting of 2965 three-component time histories from 654 seismic events with the magnitude range 3.5 to 7.7 at distances less than 300 km recorded between 1975 and 2019. The functional form of the proposed models consists of some variables, including moment magnitude (Mw), Joyner-Boore distance (RJB), average velocity of shear waves for the upper 30-m depth (Vs30), and faulting mechanisms. The random-effects algorithm is used for conducting the regression analysis, which considers inter-event and intra-event error terms, separately. To verify the trend of attenuation in the proposed models, some comparisons have been made between the proposed models in the current study and those developed for other similar regions.

Fishing out regular polysemy with the Gener (generic) relation

Lexical Systems are formal network models of natural language lexicons. They are characterized by their graph structure that is mainly woven by paradigmatic and syntagmatic lexical relations known as lexical functions. Being organized as “social networks of words,” Lexical Systems are radically distinct from taxonomic models which organize lexical units within hierarchized classes. In spite of their apparent messiness, these structures are perfectly suited for the storage of lexical regularities. This paper is devoted to the Gener (generic) lexical function and its significance for the identification and modeling of regular polysemy in network models of the Lexical System family. We show how the systematic lexicographic encoding of Gener relations allows for the study of polysemy patterns and the uniform modeling of this phenomenon in lexicographic models. The approach is illustrated based on the lexicographic construction of a Lexical System – the French Lexical Network (fr-LN) –, using the generic term Fr. fleur ‘flower’.

The distributions under two species-tree models of the number of root ancestral configurations for matching gene trees and species trees

For a pair consisting of a gene tree and a species tree, the ancestral configurations at a species-tree internal node are the distinct sets of gene lineages that can be present at that node. The enumeration of root ancestral configurations—ancestral configurations at the species-tree root—assists in describing the complexity of gene-tree probability calculations in evolutionary biology. Assuming that the gene tree and species tree match in topology, we study the distribution of the number of root ancestral configurations of a random labeled tree topology under the uniform and Yule–Harding models. We employ analytic combinatorics, considering ancestral configurations in the context of additive tree parameters and using singularity analysis to evaluate asymptotic growth of the coefficients of generating functions. For both models, we obtain asymptotic lognormal distributions for the number of root ancestral configurations. For Yule–Harding random trees, we also obtain the asymptotic mean (∼1.425n) and variance (∼2.045n) of the number of root ancestral configurations, paralleling previous results for the uniform model (mean (4/3)n, variance ∼1.822n). A methodological innovation is that to obtain the Yule–Harding asymptotic variance, singularity analysis is conducted from the Riccati differential equation that the generating function satisfies—without possessing the generating function itself.

Zoom Transformer for Skeleton-Based Group Activity Recognition

Skeleton-based human action recognition has attracted increasing attention and many methods have been proposed to boost the performance. However, these methods still confront three main limitations: 1) Focusing on single-person action recognition while neglecting the group activity of multiple people (more than 5 people). In practice, multi-person group activity recognition via skeleton data is also a meaningful problem. 2) Unable to mine high-level semantic information from the skeleton data, such as interactions among multiple people and their positional relationships. 3) Existing datasets used for multi-person group activity recognition are all RGB videos involved, which cannot be directly applied to skeleton-based group activity analysis. To address these issues, we propose a novel Zoom Transformer to exploit both the low-level single-person motion information and the high-level multi-person interaction information in a uniform model structure with carefully designed Relation-aware Maps. Besides, we estimate the multi-person skeletons from the existing real-world video datasets i.e. Kinetics and Volleyball-Activity, and release two new benchmarks to verify the effectiveness of our Zoom Transfromer. Extensive experiments demonstrate that our model can effectively cope with the skeleton-based multi-person group activity. Additionally, experiments on the large-scale NTU-RGB+D dataset validate that our model also achieves remarkable performance for single-person action recognition. The code and the skeleton data are publicly available at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/Kebii/Zoom-Transformer</uri>

Tissue-specific accumulation, depuration, and effects of perfluorooctanoic acid on fish: Influences of aqueous pH and sex

Perfluorooctanoic acid (PFOA) is widely distributed in nature, particularly in aquatic environments. Its bioaccumulation and toxicity in aquatic organisms can be affected by both the chemical status of PFOA in water and the physiology of the organism. However, research on the patterns of these effects is scarce. In this study, we investigated the influence of aqueous pH (pH 6, acidic; pH 7.5, neutral; pH 9, basic) and fish sex on PFOA uptake, clearance, and biochemical effects in crucian carp (C. auratus) using flow-through exposure. In the 17-d kinetic experiment, PFOA bioaccumulation adhered to a uniform first-order model in which PFOA uptake rates from water to blood and liver in acidic conditions were faster than those in other conditions, indicating possible acidic pH influence on PFOA uptake. PFOA clearance rates in these compartments of males were slower than in females, which was attributed to the notably stronger expression of Oat2 (organic anion transporter 2, responsible for reabsorption) in the kidneys of males. Similar responses were observed for peroxisome proliferation-related biomarkers at different pH levels and in different sexes. These biochemical responses were driven by the internal concentrations of PFOA. The inhibition acetylcholinesterase activity in the fish brain was closely linked to changes in P-glycoprotein content, demonstrating a protective relationship. Collectively, an aqueous pH lower than 7.5 might affect the uptake of PFOA by fish. The clearance discrepancies between the sexes highlight the importance of anion carriers for ionizable organic compounds in aquatic organisms.

High-fidelity standard model reconstruction and verification of an airliner based on point clouds.

Computational fluid dynamics (CFD) numerical simulation as the primary research tool is particularly essential for its credibility during the aerodynamic design of aircraft. To further promote CFD verification and validation on the airliner, a high-fidelity model reconstruction of the airliner is fundamental. Based on this, we put forward a novel framework, to our best knowledge, to reconstruct a high-fidelity standard model for an airliner efficiently, and the feasibility and accuracy of these reconstructed models are accessed by the CFD simulation-based validation method. First and foremost, a laser scanner was placed at each station around the airliner to scan and acquire multiview point clouds. Afterwards, the truncated least-squares-based algorithm was adopted to register these point clouds entirely. Additionally, we fitted the nonuniform rational basis spline surface based on the least-squares progressive and iterative approximation algorithm. Finally, CFD simulation results were compared and analyzed with the aerodynamic data obtained by the aircraft manufacturer under the same Mach number of the uniform model. It turns out that the coincidence between them is high, and the changing trend is basically consistent. Hence, this method is highly feasible and can establish a high-fidelity standard model of an airliner with unified high and low speeds so that its appearance, test data, and research results can be adopted as the standard data for CFD verification and validation.

Surface Smoothing by Atomic Layer Deposition and Etching for the Fabrication of Nanodevices.

In many nano(opto)electronic devices, the roughness at surfaces and interfaces is of increasing importance, with roughness often contributing toward losses and defects, which can lead to device failure. Consequently, approaches that either limit roughness or smoothen surfaces are required to minimize surface roughness during fabrication. The atomic-scale processing techniques atomic layer deposition (ALD) and atomic layer etching (ALE) have experimentally been shown to smoothen surfaces, with the added benefit of offering uniform and conformal processing and precise thickness control. However, the mechanisms which drive smoothing during ALD and ALE have not been investigated in detail. In this work, smoothing of surfaces by ALD and ALE is studied using finite difference simulations that describe deposition/etching as a front propagating uniformly and perpendicular to the surface at every point. This uniform front propagation model was validated by performing ALD of amorphous Al2O3 using the TMA/O2 plasma. ALE from the TMA/SF6 plasma was also studied and resulted in faster smoothing than predicted by purely considering uniform front propagation. Correspondingly, it was found that for such an ALE process, a second mechanism contributes to the smoothing, hypothesized to be related to curvature-dependent surface fluorination. Individually, the atomic-scale processing techniques enable smoothing; however, ALD and ALE will need to be combined to achieve thin and smooth films, as is demonstrated and discussed in this work for multiple applications.

Design of surface micro texture in the cutter-chip contact area of a cemented carbide cutter

Placing micro textures on a cutter surface can enhance the cutter-chip and cutter-workpiece contact, improving the cutter performance and machined surface quality. However, both the proper placement of micro textures and careful modeling of their density function are required for optimizing the cutting performance. In this study, a ball end milling cutter was utilized to demonstrate how these can be achieved. Initially, the theoretical cutter-chip contact length of the was calculated based on the chip curl theory and the theoretical cutter-chip contact area was obtained by combining the theories of cutter contact area and micro texture placement. Then, a mathematical model describing the micro texture distribution was established using a uniform density function, which allowed the determination of the specific distribution model for the micro textures. Finally, both simulations and experiments were used to validate the accuracy of the theoretical solution for the cutter-chip contact area and the uniformity of the micro texture density function. The results showed that the theoretical cutter-chip contact area and the uniform micro texture density mathematical model are consistent with the simulation and experimental results. The results reported in this paper provide a theoretical basis for the accurate preparation of micro textures.

Two results about the Sackin and Colless indices for phylogenetic trees and their shapes.

The Sackin and Colless indices are two widely-used metrics for measuring the balance of trees and for testing evolutionary models in phylogenetics. This short paper contributes two results about the Sackin and Colless indices of trees. One result is the asymptotic analysis of the expected Sackin and Colless indices of tree shapes (which are full binary rooted unlabelled trees) under the uniform model where tree shapes are sampled with equal probability. Another is a short direct proof of the closed formula for the expected Sackin index of phylogenetic trees (which are full binary rooted trees with leaves being labelled with taxa) under the uniform model.

Transition metal halide complexes of 4′-aminoacetophenone: Syntheses, structures, and magnetic behavior

A family of eight compounds of the general formula [(C8H9NO)2MX2] or [(C8H9NO)2(H2O)2MX2], (M = Ni, Co, Cu, Zn; X = Cl, Br) has been prepared and the compounds characterized by combustion analysis, IR, single-crystal X-ray diffraction and variable temperature magnetization measurements. [[(C8H9NO)2(H2O)nMX2], (1, n = 0, M = Cu, X = Cl; 2, n = 0, M = Cu, X = Br; 3, n = 2, M = Ni, X = Cl; 4, n = 2, M = Ni, X = Br; 5, n = 2, M = Co, X = Cl; 6, n = 2, M = Co, X = Br; 7, n = 0, M = Zn, X = Cl; 8, n = 0, M = Zn, X = Br.) The eight compounds crystallize in three distinct space groups and have coordination number of either four (compounds 1, 2, 7, and 8) or six (compounds 3–6). Compounds 1 and 2 are slightly distorted square planar, compounds 3–6 are slightly distorted octahedral, and compounds 7 and 8 are slightly distorted tetrahedral. All eight compounds form chains either through bihalide interactions (1 and 2) or systems of hydrogen bonds (3–8). Chains are linked into layers through short halide…halide (1, 2, 7) and both traditional and non-traditional hydrogen bonds. The complexes have also been studied via variable temperature magnetic susceptibility measurements. Data for Cu(II) complexes 1 and 2 the 1D-Heisenberg uniform chain model with J/kB of −13.4(6) K and −14.3(4) K, respectively, with antiferromagnetic interchain interactions (θ = −4.1(5) K, −2.5(5) K, respectively) following the H=-J∑si∙sj Hamiltonian. The Ni(II) and Co(II) compounds showed temperature dependent moments which were well-modeled as arising due to single-ion anisotropy.

Making Common Fund data more findable: catalyzing a data ecosystem.

The Common Fund Data Ecosystem (CFDE) has created a flexible system of data federation that enables researchers to discover datasets from across the US National Institutes of Health Common Fund without requiring that data owners move, reformat, or rehost those data. This system is centered on a catalog that integrates detailed descriptions of biomedical datasets from individual Common Fund Programs' Data Coordination Centers (DCCs) into a uniform metadata model that can then be indexed and searched from a centralized portal. This Crosscut Metadata Model (C2M2) supports the wide variety of data types and metadata terms used by individual DCCs and can readily describe nearly all forms of biomedical research data. We detail its use to ingest and index data from 11 DCCs.

Improvement X-ray radiation shield characteristics of composite cement/Titanium dioxide (TiO2)/Barium carbonate (BaCO3): Stability crystal structure and chemical bonding

The stability crystal structural and chemical bonding characteristics of composite cement filled with titanium dioxide (TiO2)/barium carbonate (BaCO3) were successfully studied through a quantitative analysis of X-ray diffraction and Fourier transform infrared spectra, respectively, for X-ray shielding applications. The Scherrer, uniform deformation model, and size–strain plot methods were used to determine the structural properties in the form of crystallite size (D), micro strain (ε), stress (σ), and energy deformation (u) of composite. D, ε, and σ shows small differences between non-irradiation and irradiation composites. The Ba–O bonding at a wavenumber of 714 cm−1 and –OH bonding at 2515 cm−1 shows a more constant position compared with that between before and after X-ray irradiation and indicated a stable crystal structure and bonding formation of composites. The best composite found in this study is composite 30% (TiO2 + BaCO3) indicated by the highest linear attenuation coefficient of 3.524 cm−1 for 60 keV, approximately 3.146 cm−1 for 70 keV, and 2.776 cm−1 for 80 keV and the lowest half-value layer and mean free path, which imply its high potential as a new X-ray shield.

On training non-uniform fuzzy partitions for function approximation using differential evolution: A study on fuzzy transform and fuzzy projection

This paper focuses on the use of differential evolution to improve the approximation properties of function approximation models based on fuzzy partitions. Two cases are considered: Fuzzy transform and Fuzzy projection, and the design of hybrid evolutionary fuzzy systems, is studied. Even though function approximation techniques based on fuzzy partitions have been well studied, few papers consider the problem of centroid selection of the basis functions. Thus, in most cases uniform fuzzy partitions are considered. By using an evolutionary algorithm a systematic approach on the selection of the partition, is provided. The optimisation problem involves the determination of the model parameters, which in our case are the fuzzy partition’s membership functions’ locations. The proposed method is tested on the scattered data approximation problem, in a regression sense, that is given a set of sparse data the latent function is approximated. Numerical studies on one and two-dimensional test functions demonstrate that the evolutionary algorithm based fuzzy projection displays high performance in terms of approximation error. Moreover, the proposed approach shows high approximation capabilities with a small number of basis functions. Comparison results, with uniform fuzzy partition models, neural networks and support vector machines, are provided.

An extended approach for the generalized powered uniform distribution.

A new uniform distribution model, generalized powered uniform distribution (GPUD), which is based on incorporating the parameter k into the probability density function (pdf) associated with the power of random variable values and includes a powered mean operator, is introduced in this paper. From this new model, the shape properties of the pdf as well as the higher-order moments, the moment generating function, the model that simulates the GPUD and other important statistics can be derived. This approach allows the generalization of the distribution presented byJayakumar and Sankaran (2016) through the new distribution. Two sets of real data related to COVID-19 and bladder cancer were tested to demonstrate the proposed model's potential. The maximum likelihood method was used to calculate the parameter estimators by applying the maxLik package in R. The results showed that this new model is more flexible and useful than other comparable models.

Estimation of the perceptual color gamut on displays.

A new method was developed to evaluate the perceived gamut of a display. A multispectral image of a white gypsum sphere was projected onto various highly chromatic lights, producing a series of images with distinct hue perceptions at the gamut boundary of displays. These images were subsequently used in a psychophysical experiment to examine the perceived color gamut. Afterwards, the visual results were further compared with the prediction results from various uniform color spaces (UCSs) and color appearance models (CAMs). The present results demonstrate that CAM16-UCS provides the most accurate prediction across the entire color gamut, whereas the cyan-to-blue region is more poorly predicted than the other hue regions for all CAMs and UCSs investigated.

Leptin Densities in Amenable Groups

Consider a positive Borel measure on a locally compact group. We define a notion of uniform density for such a measure, which is based on a group invariant introduced by Leptin in 1966. We then restrict to unimodular amenable groups and to translation bounded measures. In that case our density notion coincides with the well-known Beurling density from Fourier analysis, also known as Banach density from dynamical systems theory. We use Leptin densities for a geometric proof of the model set density formula, which expresses the density of a uniform regular model set in terms of the volume of its window, and for a proof of uniform mean almost periodicity of such model sets.

Constant Hue Loci in Rec. 2020 Gamut under an HDR Condition

Hue linearity is critically important to uniform color spaces and color appearance models. Past studies investigating hue linearity only covered relatively small color gamuts, which was generally acceptable for conventional display technologies. The recent development of HDR and WCG display technologies has motivated the development of new color spaces (e.g., IC&lt;sub&gt;T&lt;/sub&gt;C&lt;sub&gt;P&lt;/sub&gt; and J&lt;sub&gt;z&lt;/sub&gt;a&lt;sub&gt;z&lt;/sub&gt;b&lt;sub&gt;z&lt;/sub&gt;). The hue linearity of these new color spaces, however, was not verified for the claimed HDR and WCG conditions, due to the lack of constant hue loci data. In this study, an experiment setup was carefully developed to produce HDR and WCG conditions, with the stimulus luminance of 3400 cd/m&#xB2; and the diffuse white luminance of 1000 cd/m&#xB2; and the stimulus chromaticities almost covering the Rec. 2020 gamut. The human observers performed a hue matching task, adjusting the hue of the test stimulus, with a hue angle step of 0.2&#xB0;, at various chroma levels to match that of the reference stimulus at 21 different hues. The derived constant hue loci were used to test the various UCSs and suggested the need to improve the hue linearity of these spaces.