Pair Of Coordinates Research Articles

Evolutionary Approach to Constructing a Deep Feedforward Neural Network for Prediction of Electronic Coupling Elements in Molecular Materials.

We present a general framework for the construction of a deep feedforward neural network (FFNN) to predict distance and orientation dependent electronic coupling elements in disordered molecular materials. An evolutionary algorithm automatizes the selection of an optimal architecture of the artificial neural network within a predefined search space. Systematic guidance, beyond minimizing the model error with stochastic gradient descent based backpropagation, is provided by simultaneous maximization of a model fitness that takes into account additional physical properties, such as the field-dependent carrier mobility. As a prototypical system, we consider hole transport in amorphous tris(8-hydroxyquinolinato)aluminum. Reference data for training and validation is obtained from multiscale ab initio simulations, in which coupling elements are evaluated using density-functional theory, for a system containing 4096 molecules. The Coulomb matrix representation is chosen to encode the explicit molecular pair coordinates into a rotation and translation invariant feature set for the FFNN. The final optimized deep feedforward neural network is tested for transport models without and with energetic disorder. It predicts electronic coupling elements and mobilities in excellent agreement with the reference data. Such a FFNN is readily applicable to much larger systems at negligible computational cost, providing a powerful surrogate model to overcome the size limitations of the ab initio approach.

Semantic repetition blindness and associative facilitation in the identification of stimuli in rapid serial visual presentation.

Repetition blindness (RB) is the inability to detect both instances of a repeated stimulus during rapid serial visual presentation (RSVP). Prior work has demonstrated RB for semantically related critical items presented as pictures, but not for word stimuli. It is not known whether the type of semantic relationship between critical items (i.e., conceptual similarity or lexical association) determines the manifestation of semantically mediated RB, or how this is affected by the format of the stimuli. These questions provided the motivation for the present study. Participants reported items presented in picture or word RSVP streams in which critical items were either low-associate category coordinates (horse-camel), high-associate noncoordinates (horse-saddle), or unrelated word pairs (horse-umbrella). Report accuracy was reduced for category coordinate critical items only when they were presented in pictorial form; accuracy for coordinate word pairs did not differ from that of their unrelated counterparts. Associated critical items were reported more accurately than unrelated critical items in both the picture and word versions of the task. We suggest that semantic RB for pictorial stimuli results from intracategory interference in the visuosemantic space; words do not reliably suffer from semantic RB because they do not necessitate semantic mediation to be reported successfully. Conversely, the associative facilitation observed in both picture and word versions of the task reflects the spread of activation between the representations of associates in the lexical network.

58: Human resources for maternal health: expanding geographic access to obstetrician/gynecologists in rwanda

The 1994 genocide decimated the Rwandan health care system. Human Resources for Health (HRH) is a Rwandan government designed program aimed to increase quality and access to health care through medical education. US OB/GYN and Rwandan faculty collaborate to support this goal by implementing medical student/resident training and faculty development. US MFMs provide consistent program support. We evaluated access to care through geospatial analysis. Evaluation of the program was measured by the number of qualified OB/GYNs trained over the first 5 years. The national impact on access to care was evaluated by geocoding the location of OB/GYNs serving in public hospitals throughout the country in 2011 (prior to initiation of the program) compared to 2016. Longitude and latitude coordinate pairs for hospitals were obtained by GPS tagging. Hospital locations were confirmed using rooftop visualization in Google Earth. To estimate population data, we obtained a WorldPop raster dataset of pregnancies in Rwanda from 2015. We used ArcGIS 10.5.1 for spatial operations and R 3.4.4 for statistical analysis. To determine the proportion of pregnant women in Rwanda within a 10 and 25 km circular buffer distance from a hospital with an OB/GYN, we used a zonal statistics tool. Cartographic output was produced using ArcGIS and consists of a basemap, national boundaries, city locations, and computed buffer zones. From 2012-2017 OB/GYNs increased 3.5-fold; annual residents graduated increased 2.6-fold. Faculty increased by 45%. In 2011, geospatial analysis demonstrated the majority of providers in Kigali. Between 2011--2016 the proportion of pregnant women living within 10 km of a hospital with OB/GYNs increased from 11.9% to 25.7% (95% CI of the difference 9.3-9.5%, p < 0.001); the proportion within 25 km increased from 26.8% to 72.8% (95% CI 46.2-45.9%, p < 0.001). University of Rwanda HRH-OB/GYN graduates now head 75% of referral hospital OB/GYN departments; others head provincial and district hospitals. Annual/Cumulative OB/GYN residency graduates OB/GYNs within 25km of pregnant population The HRH-Rwanda program significantly increased the number of OB/GYN graduates and new academic faculty. Geospatial analysis of OB/GYN presence in public hospitals demonstrated a marked nationwide improvement in access to care for Rwandan women. This study is the first spatial analysis of OB/GYN specialty care in public hospitals in sub-Saharan Africa.

Semianalytical Solutions of Relative Motions with Applications to Periodic Orbits about a Nominal Circular Orbit

In the dynamical model of relative motion with circular reference orbit, the equilibrium points are distributed on the circle where the leader spacecraft is located. In this work, analytical solutions of periodic configurations around an arbitrary equilibrium point are constructed by taking Lindstedt-Poincaré (L-P) and polynomial expansion methods. Based on L-P approach, periodic motions are expanded as formal series of in-plane and out-of-plane amplitudes. According to the method of polynomial expansions, a pair of modal coordinates is chosen, and the remaining state variables are expressed as polynomial series about the modal coordinates. In order to check the validity of series solutions constructed, the practical convergence is evaluated. Considering the fact that relative motion model is a special case of restricted three-body problem, the periodic configurations constructed in the model of relative motion are taken as starting solutions to numerically identify the periodic orbits in restricted three-body problem by means of continuation technique with the mass of system as continuation parameter.

Google timeline accuracy assessment and error prediction

Google Location Timeline, once activated, allows to track devices and save their locations. This feature might be useful in the future as available data for evidence in investigations. For that, the court would be interested in the reliability of these data. The position is presented in the form of a pair of coordinates and a radius, hence the estimated area for tracked device is enclosed by a circle. This research focuses on the assessment of the accuracy of the locations given by Google Location History Timeline, which variables affect this accuracy and the initial steps to develop a linear multivariate model that can potentially predict the actual error with respect to the true location considering environmental variables. The determination of the potential influential variables (configuration of mobile device connectivity, speed of movement and environment) was set through a series of experiments in which the true position of the device was recorded with a reference Global Positioning System (GPS) device with a superior order of accuracy. The accuracy was assessed measuring the distance between the Google provided position and the de facto one, later referred to as Google error. If this Google error distance is less than the radius provided, we define it as a hit. The configuration that has the largest hit rate is when the mobile device has GPS available, with a 52% success. Then the use of 3G and 2G connection go with 38% and 33% respectively. The Wi-Fi connection only has a hit rate of 7%. Regarding the means of transport, when the connection is 2G or 3G, the worst results are in Still with a hit rate of 9% and the best in Car with 57%. Regarding the prediction model, the distances and angles from the position of the device to the three nearest cell towers, and the categorical (non-numerical) variables of Environment and means of transport were taking as input variables in this initial study. To evaluate the usability of a model, a Model hit is defined when the actual observation is within the 95% confidence interval provided by the model. Out of the models developed, the one that shows the best results was the one that predicted the accuracy when the used network is 2G, with 76% of Model hits. The second model with best performance had only a 23% success (with the mobile network set to 3G).

Revealing compactness of basins of attraction of multi-DoF dynamical systems

Abstract Global properties of Multi-Degrees-of-Freedom (M-DoF) systems, in particular phase space organization, are largely unexplored due to the computational challenge requested to build basins of attraction. To overcome this problem, various techniques have been developed, some trying to improve algorithms and to exploit high speed computing, others giving up to possibility of having the exact phase space organization and trying to extract major information on a probability base. Following the last approach, this work exploits the method of “basin stability” (Menck et al., 2013) in order to drastically reduce the numerical effort. The probability of reaching the attractors is evaluated using a reasonable number of trials with random initial conditions. Then we investigate how this probability depends on particular generalized coordinate or a pair of coordinates. The method allows to obtain information about the basins compactness and reveals particular features of the phase space topology. We focus the study on a 2-DoF multistable paradigmatic system represented by a parametric pendulum on a moving support and model of a Church Bell. The trustworthiness of the proposed approach is enhanced through the comparison with the classical computation of basins of attraction performed in the full range of initial conditions. The proposed approach can be effectively utilized to investigate the phase space in multidimensional nonlinear dynamical systems by providing additional insights over traditional methods.

A routine operational backscattering coefficient regrouping algorithm for a HY-2A scatterometer

The routine operational sigma0 regrouping method is proposed for a HY-2A scatterometer (HSCAT) that maps time-ordered sigma0s and related parameters into a subtrack aligned grid of wind vector cells (WVCs). The regrouping method consists of two critical steps: ground grid generation and sigma0 resampling. The HSCAT uses subtrack swath coordinates, in which the nadir track of the satellite represents the center and the designated positions are specified in terms of a pair of along-track and cross-track coordinates. To calculate the subtrack coordinates for each sigma0, a “triangle marking” resampling method is developed. Three points, including the point of intersection, the center of a pulse footprint, and the origin of the subtrack coordinate system, form a right triangle; the length of the two right-angled sides is used to represent the cross-track and the along-track coordinates in the subtrack coordinate system. In addition, a nadir point interpolation correction is used to ensure the operation of the regrouping algorithm when the nadir point positional information is missing. To illustrate the ability of the proposed regrouping algorithm, the distribution of the WVC positions and wind vector retrieval results are analyzed, which show that the proposed regrouping algorithm meets the requirements for high-quality sea surface wind field retrieval.

Pseudo-conformer models for linear molecules: Joint treatment of spectroscopic, electron diffraction and ab initio data for the C3O2 molecule

Dynamic analysis of the molecules with large-amplitude motions (LAM) based on the pseudo-conformer approach has been successfully applied to various molecules. Floppy linear molecules present a special class of molecular structures that possess a pair of conjugate LAM coordinates but allow one-dimensional treatment. In this paper, previously developed treatment for the semirigid molecules is applied to the carbon suboxide molecule. This molecule characterized by the extremely large CCC bending has been thoroughly investigated by spectroscopic and ab initio methods. However, the earlier electron diffraction investigations were performed within a static approach, obtaining thermally averaged parameters. In this paper we apply a procedure aimed at obtaining the short list of self-consistent reference geometry parameters of a molecule, while all thermally averaged parameters are calculated based on reference geometry, relaxation dependencies and quadratic and cubic force constants. We show that such a model satisfactorily describes available electron diffraction evidence with various QC bending potential energy functions when r.m.s. CCC angle is in the interval 151 ± 2°. This leads to a self-consistent molecular model satisfying spectroscopic and GED data. The parameters for linear reference geometry have been defined as re(CO) = 1.161(2) Å and re(CC) = 1.273(2) Å.

Three‐body molecular states of the system in the Born–Oppenheimer approximation

AbstractIn this work, we present a quantum mechanical treatment of the three‐body molecular system in the Born–Oppenheimer (BO) approximation, were the nuclei dynamics is evaluated over the potential energy surfaces (PES) induced by the electronic states. The PES corresponding to the two lowest electronic levels are the ones described by Martinazzo et al. (Chem. Phys. 2003, 287, 335), and are used to write the three‐body Schrdinger equation of the three atomic system. We use the generalized Sturmian functions method to expand the wave functions in each (distinguishable) pair of relative coordinates or Jacobi pairs, and analyze the convergence differences between the series. A partial‐wave decomposition of the potential is proposed to simplify the Hamiltonian matrix element calculation. Bound states are considered for the ground and first excited electronic PES, the spreading of energies after sudden electronic transitions studied, and the break‐up probability induced by the sudden change of the PES evidenced.

Effect of the Age on Central Incisors and Canine Teeth Color Correlation

Aim: The objective was to determine whether there were significant correlations in the three color coordinates of central incisors and canine teeth with age such as the Commission Internationale de l’Eclairage (CIE) L*, a*, b* system.Materials and Methods: The natural maxillary central incisor and maxillary canine teeth of a sample of 302 individuals (n=104 male, n=168 female) were measured by the Vita Easyshade V spectrophotometer. Pearson correlations between each pair of the color coordinates were determined (p<0.01).Results: Based on correlation analyses, for central incisors all the color coordinate parameters showed significant correlations but there was no correlation for canine teeth with all of three parameters.Conclusions: When age increases, the central incisors become darker, more red, and more yellow. The same correlation was found for the canine teth but the result is not significant.

Host Distribution Does Not Limit the Range of the Tick Ixodes ricinus but Impacts the Circulation of Transmitted Pathogens.

Ticks, pathogens, and vertebrates interact in a background of environmental features that regulate the densities of ticks and vertebrates, affecting their contact rates and thence the circulation of the pathogens. Regional scale studies are invaluable sources of information about the regulation of these interactions, but a large-scale analysis of the interaction of communities of ticks, hosts, and the environment has been never modeled. This study builds on network analysis, satellite-derived climate and vegetation, and environmental modeling, quantifying the interactions between the tick Ixodes ricinus and the transmitted bacteria of the complex Borrelia burgdorferi s.l. in the Western Palaearctic. We derived the rates of contact of the tick with 162 species of vertebrates recorded as hosts, and the relative importance of each vertebrate in the circulation of the pathogen. We compiled more than 11 millions of pairs of coordinates of the vertebrates, deriving distribution models of each species and the relative faunal composition in the target territory. The results of the modeling of the distribution of the tick and its hosts, weighted by their importance in the circulation of Borrelia captured the spatial patterns of interactions that allow the circulation of the pathogen. Results indicate that both I. ricinus and B. burgdorferi s.l. are supported in the Western Palaearctic by complex communities of vertebrates, which have large distribution ranges. This high functional redundancy results in the pervasiveness of B. burgdorferi s.l., which depends on the gradient of contributions of the large community of vertebrates, instead of relying on a few dominant vertebrates, which was the prevailing paradigm. Most prominent reservoirs of the pathogen are distributed in specific regions of the environmental niche. However, literally dozens of potential reservoirs can colonize many other environmental regions, marginally but efficiently contributing to the circulation of the pathogen. These results consistently point to the need of evaluating the beta-diversity of the community of vertebrates acting as reservoirs of the pathogen to better know the interactions with the vector. They also demonstrate why the pathogen is so resilient to perturbations in the composition of the reservoirs.

Constructing error-correcting binary codes using transitive permutation groups

Transitive permutation groups are recurrent in the study of automorphism groups of combinatorial objects. For binary error-correcting codes, groups are here considered that act transitively on the pairs of coordinates and coordinate values. By considering such groups in an exhaustive manner and carrying out computer searches, the following new bounds are obtained on A2(n,d), the maximum size of a binary code of length n and minimum distance d: A2(17,3)≥5632, A2(20,3)≥40960, A2(21,3)≥81920, A2(22,3)≥163840, A2(23,3)≥327680, A2(23,9)≥136, and A2(24,5)≥17920.

The semantic network, lexical access, and reading comprehension in monolingual and bilingual children: An individual differences study

ABSTRACTUsing a semantic priming experiment, the influence of lexical access and knowledge of semantic relations on reading comprehension was studied in Dutch monolingual and bilingual minority children. Both context-independent semantic relations in the form of category coordinates and context-dependent semantic relations involving concepts that co-occur in certain contexts were tested in an auditory animacy decision task, along with lexical access. Reading comprehension and the control variables vocabulary size, decoding skill, and mental processing speed were tested by means of standardized tasks. Mixed-effects modeling was used to obtain individual priming scores and to study the effect of individual differences in the various predictor variables on the reading scores. Semantic priming was observed for the coordinate pairs but not the context-dependently related pairs, and neither context-independent priming nor lexical access predicted reading comprehension. Only vocabulary size significantly contributed to the reading scores, emphasizing the importance of the number of words known for reading comprehension. Finally, the results show that the monolingual and bilingual children perform similarly on all measures, suggesting that in the current Dutch context, language status may not be highly predictive of vocabulary knowledge and reading comprehension skill.

JED: a Java Essential Dynamics Program for comparative analysis of protein trajectories

BackgroundEssential Dynamics (ED) is a common application of principal component analysis (PCA) to extract biologically relevant motions from atomic trajectories of proteins. Covariance and correlation based PCA are two common approaches to determine PCA modes (eigenvectors) and their eigenvalues. Protein dynamics can be characterized in terms of Cartesian coordinates or internal distance pairs. In understanding protein dynamics, a comparison of trajectories taken from a set of proteins for similarity assessment provides insight into conserved mechanisms. Comprehensive software is needed to facilitate comparative-analysis with user-friendly features that are rooted in best practices from multivariate statistics.ResultsWe developed a Java based Essential Dynamics toolkit called JED to compare the ED from multiple protein trajectories. Trajectories from different simulations and different proteins can be pooled for comparative studies. JED implements Cartesian-based coordinates (cPCA) and internal distance pair coordinates (dpPCA) as options to construct covariance (Q) or correlation (R) matrices. Statistical methods are implemented for treating outliers, benchmarking sampling adequacy, characterizing the precision of Q and R, and reporting partial correlations. JED output results as text files that include transformed coordinates for aligned structures, several metrics that quantify protein mobility, PCA modes with their eigenvalues, and displacement vector (DV) projections onto the top principal modes. Pymol scripts together with PDB files allow movies of individual Q- and R-cPCA modes to be visualized, and the essential dynamics occurring within user-selected time scales. Subspaces defined by the top eigenvectors are compared using several statistical metrics to quantify similarity/overlap of high dimensional vector spaces. Free energy landscapes can be generated for both cPCA and dpPCA.ConclusionsJED offers a convenient toolkit that encourages best practices in applying multivariate statistics methods to perform comparative studies of essential dynamics over multiple proteins. For each protein, Cartesian coordinates or internal distance pairs can be employed over the entire structure or user-selected parts to quantify similarity/differences in mobility and correlations in dynamics to develop insight into protein structure/function relationships.

Happy sad demarcation from facial images using neural networks

The aim of this paper is to discuss the development of an efficient neural network that demarcates primary emotions of humans such as happiness and sadness. The neural network implements a back-propagation algorithm that minimizes the error in the network, by traversing back in the network and rectifying the weights of the nodes in the layers of the neural network. The artificial neural network takes inputs in the form of co-ordinate pairs that constitute the facial fiducial points around the lips. The three pairs of points are the six input layer nodes. These nodes are connected to two nodes in the hidden layer which are connected to two output nodes. The output layer nodes are the results of the network and these nodes are binary. If the emotion is happy, the first node will be active having a value 1 while second node will be inactive having a value 0 and vice versa if the emotion is sad. Using the data generated by the algorithm the artificial neural network is trained. The paper also compares the effect of normalization in neural networks by comparing the confusion matrix for normalized input data and raw input data. Keywords: Image analysis; Emotion Recognition; Neural Networks; Facial Images.

What Does \u201cWithout Loss of Generality\u201d Mean, and How Do We Detect It

When one goes from a geometrical statement to an algebraic statement, the immediate translation is to replace every point by a pair of coordinates, if in the plane (or more as required). A statement with N points is then a statement with 2N (or 3N or more) variables, and the complexity of tools like cylindrical algebraic decomposition is doubly exponential in the number of variables. Hence one says “without loss of generality, A is at (0,0)” and so on. How might one automate this, in particular the detection that a “without loss of generality” argument is possible, or turn it into a procedure (and possibly even a formal proof)?

Optimal convection cooling flows in general 2D geometries

We generalize a recent method for computing optimal 2D convection cooling flows in a horizontal layer to a wide range of geometries, including those relevant for technological applications. We write the problem in a conformal pair of coordinates which are the pure conduction temperature and its harmonic conjugate. We find optimal flows for cooling a cylinder in an annular domain, a hot plate embedded in a cold surface, and a channel with a hot interior and cold exterior. With a constraint of fixed kinetic energy, the optimal flows are all essentially the same in the conformal coordinates. In the physical coordinates, they consist of vortices ranging in size from the length of the hot surface to a small cutoff length at the interface of the hot and cold surfaces. With the constraint of fixed enstrophy (or fixed rate of viscous dissipation), a geometry-dependent metric factor appears in the equations. The conformal coordinates are useful here because they map the problems to a rectangular domain, facilitating numerical solutions. With a small enstrophy budget, the optimal flows are dominated by vortices that have the same size as the flow domain.

Location-based big data analytics for guessing the next Foursquare check-ins

Location-based services on GPS-enabled smartphones are undergoing strong growth. Capitalizing on the popularity of this geo-location social media, a mobile app called Foursquare is developed to recommend its users places where they may be interested in, to travel from their current proximities. Such location data, in the form of check-ins by Foursquare, have huge business potentials including marketing, advertising and consumers' behaviors analysis. Many researchers from both academia and industries are seriously looking into this location-based big data which comes in high velocity (with millions of users and frequent geo-tagging), and wide variety (with potentially many meta-data and associations), accumulating into a huge volume. One of the fundamental analytics in such big data is to guess which check-in locations a user would move to, as a prerequisite for sequential mining and other lifestyle pattern analysis. This paper reports a novel, but simple big data analytic by sampling a portion of location data for predicting the next check-in locations. This proposed analytic does not need every individual user's history path and ID to match the history path of the current user in the database in order to infer a prediction. We show by a simulation experiment based on a Foursquare dataset that a minimum of two pairs of coordinates are required to provide a prediction. Several variables such as segment lengths, number of check-ins, and time factors are investigated in the experiment in relation to the prediction accuracy.

Super‐speed up robust features image geometrical registration algorithm

Speed up robust features (SURF) image geometrical registration algorithm available tends to have a one-to-many association problem in feature association. One feature point in an image is associated with multiple feature points in another image, of which some or even all are mismatching points. Coordinates of these mismatching points are used to compute transformation matrix, making it difficult to obtain desirable registration. To solve this problem of SURF algorithm, super-SURF image geometrical registration algorithm is proposed, in which information richness areas are selected to detect feature points and to implement feature points association. The degree of closeness of multiple feature points from the one-to-many feature point pairs is analysed in order to remove feature point pairs with larger errors and retain those with smaller errors. Transformation matrix is then determined with coordinates of feature point pairs retained. Registration image can be obtained after transformation of floating image. Experimental results indicate that super-SURF image geometrical registration algorithm is of higher matching accuracy with less running time than SURF algorithm.

Monte Carlo MP2 on Many Graphical Processing Units.

In the Monte Carlo second-order many-body perturbation (MC-MP2) method, the long sum-of-product matrix expression of the MP2 energy, whose literal evaluation may be poorly scalable, is recast into a single high-dimensional integral of functions of electron pair coordinates, which is evaluated by the scalable method of Monte Carlo integration. The sampling efficiency is further accelerated by the redundant-walker algorithm, which allows a maximal reuse of electron pairs. Here, a multitude of graphical processing units (GPUs) offers a uniquely ideal platform to expose multilevel parallelism: fine-grain data-parallelism for the redundant-walker algorithm in which millions of threads compute and share orbital amplitudes on each GPU; coarse-grain instruction-parallelism for near-independent Monte Carlo integrations on many GPUs with few and infrequent interprocessor communications. While the efficiency boost by the redundant-walker algorithm on central processing units (CPUs) grows linearly with the number of electron pairs and tends to saturate when the latter exceeds the number of orbitals, on a GPU it grows quadratically before it increases linearly and then eventually saturates at a much larger number of pairs. This is because the orbital constructions are nearly perfectly parallelized on a GPU and thus completed in a near-constant time regardless of the number of pairs. In consequence, an MC-MP2/cc-pVDZ calculation of a benzene dimer is 2700 times faster on 256 GPUs (using 2048 electron pairs) than on two CPUs, each with 8 cores (which can use only up to 256 pairs effectively). We also numerically determine that the cost to achieve a given relative statistical uncertainty in an MC-MP2 energy increases as O(n3) or better with system size n, which may be compared with the O(n5) scaling of the conventional implementation of deterministic MP2. We thus establish the scalability of MC-MP2 with both system and computer sizes.