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Sample records for multifactor dimensionality reduction

  1. Risk score modeling of multiple gene to gene interactions using aggregated-multifactor dimensionality reduction

    Directory of Open Access Journals (Sweden)

    Dai Hongying

    2013-01-01

    Full Text Available Abstract Background Multifactor Dimensionality Reduction (MDR has been widely applied to detect gene-gene (GxG interactions associated with complex diseases. Existing MDR methods summarize disease risk by a dichotomous predisposing model (high-risk/low-risk from one optimal GxG interaction, which does not take the accumulated effects from multiple GxG interactions into account. Results We propose an Aggregated-Multifactor Dimensionality Reduction (A-MDR method that exhaustively searches for and detects significant GxG interactions to generate an epistasis enriched gene network. An aggregated epistasis enriched risk score, which takes into account multiple GxG interactions simultaneously, replaces the dichotomous predisposing risk variable and provides higher resolution in the quantification of disease susceptibility. We evaluate this new A-MDR approach in a broad range of simulations. Also, we present the results of an application of the A-MDR method to a data set derived from Juvenile Idiopathic Arthritis patients treated with methotrexate (MTX that revealed several GxG interactions in the folate pathway that were associated with treatment response. The epistasis enriched risk score that pooled information from 82 significant GxG interactions distinguished MTX responders from non-responders with 82% accuracy. Conclusions The proposed A-MDR is innovative in the MDR framework to investigate aggregated effects among GxG interactions. New measures (pOR, pRR and pChi are proposed to detect multiple GxG interactions.

  2. Mining nutrigenetics patterns related to obesity: use of parallel multifactor dimensionality reduction.

    Science.gov (United States)

    Karayianni, Katerina N; Grimaldi, Keith A; Nikita, Konstantina S; Valavanis, Ioannis K

    2015-01-01

    This paper aims to enlighten the complex etiology beneath obesity by analysing data from a large nutrigenetics study, in which nutritional and genetic factors associated with obesity were recorded for around two thousand individuals. In our previous work, these data have been analysed using artificial neural network methods, which identified optimised subsets of factors to predict one's obesity status. These methods did not reveal though how the selected factors interact with each other in the obtained predictive models. For that reason, parallel Multifactor Dimensionality Reduction (pMDR) was used here to further analyse the pre-selected subsets of nutrigenetic factors. Within pMDR, predictive models using up to eight factors were constructed, further reducing the input dimensionality, while rules describing the interactive effects of the selected factors were derived. In this way, it was possible to identify specific genetic variations and their interactive effects with particular nutritional factors, which are now under further study.

  3. A Simple and Computationally Efficient Approach to Multifactor Dimensionality Reduction Analysis of Gene-Gene Interactions for Quantitative Traits

    OpenAIRE

    Gui, Jiang; Moore, Jason H.; Williams, Scott M.; Andrews, Peter; Hillege, Hans L.; van der Harst, Pim; Navis, Gerjan; Van Gilst, Wiek H.; Asselbergs, Folkert W.; Gilbert-Diamond, Diane

    2013-01-01

    We present an extension of the two-class multifactor dimensionality reduction (MDR) algorithm that enables detection and characterization of epistatic SNP-SNP interactions in the context of a quantitative trait. The proposed Quantitative MDR (QMDR) method handles continuous data by modifying MDR's constructive induction algorithm to use a T-test. QMDR replaces the balanced accuracy metric with a T-test statistic as the score to determine the best interaction model. We used a simulation to ide...

  4. Multifactor dimensionality reduction analysis identifies specific nucleotide patterns promoting genetic polymorphisms

    Directory of Open Access Journals (Sweden)

    Arehart Eric

    2009-03-01

    Full Text Available Abstract Background The fidelity of DNA replication serves as the nidus for both genetic evolution and genomic instability fostering disease. Single nucleotide polymorphisms (SNPs constitute greater than 80% of the genetic variation between individuals. A new theory regarding DNA replication fidelity has emerged in which selectivity is governed by base-pair geometry through interactions between the selected nucleotide, the complementary strand, and the polymerase active site. We hypothesize that specific nucleotide combinations in the flanking regions of SNP fragments are associated with mutation. Results We modeled the relationship between DNA sequence and observed polymorphisms using the novel multifactor dimensionality reduction (MDR approach. MDR was originally developed to detect synergistic interactions between multiple SNPs that are predictive of disease susceptibility. We initially assembled data from the Broad Institute as a pilot test for the hypothesis that flanking region patterns associate with mutagenesis (n = 2194. We then confirmed and expanded our inquiry with human SNPs within coding regions and their flanking sequences collected from the National Center for Biotechnology Information (NCBI database (n = 29967 and a control set of sequences (coding region not associated with SNP sites randomly selected from the NCBI database (n = 29967. We discovered seven flanking region pattern associations in the Broad dataset which reached a minimum significance level of p ≤ 0.05. Significant models (p Conclusion The present study represents the first use of this computational methodology for modeling nonlinear patterns in molecular genetics. MDR was able to identify distinct nucleotide patterning around sites of mutations dependent upon the observed nucleotide change. We discovered one flanking region set that included five nucleotides clustered around a specific type of SNP site. Based on the strongly associated patterns identified in

  5. FAM-MDR: a flexible family-based multifactor dimensionality reduction technique to detect epistasis using related individuals.

    Directory of Open Access Journals (Sweden)

    Tom Cattaert

    Full Text Available We propose a novel multifactor dimensionality reduction method for epistasis detection in small or extended pedigrees, FAM-MDR. It combines features of the Genome-wide Rapid Association using Mixed Model And Regression approach (GRAMMAR with Model-Based MDR (MB-MDR. We focus on continuous traits, although the method is general and can be used for outcomes of any type, including binary and censored traits. When comparing FAM-MDR with Pedigree-based Generalized MDR (PGMDR, which is a generalization of Multifactor Dimensionality Reduction (MDR to continuous traits and related individuals, FAM-MDR was found to outperform PGMDR in terms of power, in most of the considered simulated scenarios. Additional simulations revealed that PGMDR does not appropriately deal with multiple testing and consequently gives rise to overly optimistic results. FAM-MDR adequately deals with multiple testing in epistasis screens and is in contrast rather conservative, by construction. Furthermore, simulations show that correcting for lower order (main effects is of utmost importance when claiming epistasis. As Type 2 Diabetes Mellitus (T2DM is a complex phenotype likely influenced by gene-gene interactions, we applied FAM-MDR to examine data on glucose area-under-the-curve (GAUC, an endophenotype of T2DM for which multiple independent genetic associations have been observed, in the Amish Family Diabetes Study (AFDS. This application reveals that FAM-MDR makes more efficient use of the available data than PGMDR and can deal with multi-generational pedigrees more easily. In conclusion, we have validated FAM-MDR and compared it to PGMDR, the current state-of-the-art MDR method for family data, using both simulations and a practical dataset. FAM-MDR is found to outperform PGMDR in that it handles the multiple testing issue more correctly, has increased power, and efficiently uses all available information.

  6. An alternative dimensional reduction prescription

    International Nuclear Information System (INIS)

    Edelstein, J.D.; Giambiagi, J.J.; Nunez, C.; Schaposnik, F.A.

    1995-08-01

    We propose an alternative dimensional reduction prescription which in respect with Green functions corresponds to drop the extra spatial coordinate. From this, we construct the dimensionally reduced Lagrangians both for scalars and fermions, discussing bosonization and supersymmetry in the particular 2-dimensional case. We argue that our proposal is in some situations more physical in the sense that it maintains the form of the interactions between particles thus preserving the dynamics corresponding to the higher dimensional space. (author). 12 refs

  7. Fermion masses from dimensional reduction

    International Nuclear Information System (INIS)

    Kapetanakis, D.; Zoupanos, G.

    1990-01-01

    We consider the fermion masses in gauge theories obtained from ten dimensions through dimensional reduction on coset spaces. We calculate the general fermion mass matrix and we apply the mass formula in illustrative examples. (orig.)

  8. Fermion masses from dimensional reduction

    Energy Technology Data Exchange (ETDEWEB)

    Kapetanakis, D. (National Research Centre for the Physical Sciences Democritos, Athens (Greece)); Zoupanos, G. (European Organization for Nuclear Research, Geneva (Switzerland))

    1990-10-11

    We consider the fermion masses in gauge theories obtained from ten dimensions through dimensional reduction on coset spaces. We calculate the general fermion mass matrix and we apply the mass formula in illustrative examples. (orig.).

  9. Dimensional Reduction and Hadronic Processes

    International Nuclear Information System (INIS)

    Signer, Adrian; Stoeckinger, Dominik

    2008-01-01

    We consider the application of regularization by dimensional reduction to NLO corrections of hadronic processes. The general collinear singularity structure is discussed, the origin of the regularization-scheme dependence is identified and transition rules to other regularization schemes are derived.

  10. Dimensional reduction in quantum gravity

    Energy Technology Data Exchange (ETDEWEB)

    Hooft, G [Rijksuniversiteit Utrecht (Netherlands). Inst. voor Theoretische Fysica

    1994-12-31

    The requirement that physical phenomena associated with gravitational collapse should be duly reconciled with the postulates of quantum mechanics implies that at a Planckian scale our world is not 3+1 dimensional. Rather, the observable degrees of freedom can best be described as if they were Boolean variables defined on a two- dimensional lattice, evolving with time. This observation, deduced from not much more than unitarity, entropy and counting arguments, implies severe restrictions on possible models of quantum gravity. Using cellular automata as an example it is argued that this dimensional reduction implies more constraints than the freedom we have in constructing models. This is the main reason why so-far no completely consistent mathematical models of quantum black holes have been found. (author). 13 refs, 2 figs.

  11. Dimensional reduction in anomaly mediation

    International Nuclear Information System (INIS)

    Boyda, Ed; Murayama, Hitoshi; Pierce, Aaron

    2002-01-01

    We offer a guide to dimensional reduction in theories with anomaly-mediated supersymmetry breaking. Evanescent operators proportional to ε arise in the bare Lagrangian when it is reduced from d=4 to d=4-2ε dimensions. In the course of a detailed diagrammatic calculation, we show that inclusion of these operators is crucial. The evanescent operators conspire to drive the supersymmetry-breaking parameters along anomaly-mediation trajectories across heavy particle thresholds, guaranteeing the ultraviolet insensitivity

  12. Multifactor dimensionality reduction reveals a three-locus epistatic interaction associated with susceptibility to pulmonary tuberculosis

    DEFF Research Database (Denmark)

    Collins, Ryan L; Hu, Ting; Wejse, Christian

    2013-01-01

    for this problem. The goal of the present study was to apply MDR to mining high-order epistatic interactions in a population-based genetic study of tuberculosis (TB). Results The study used a previously published data set consisting of 19 candidate single-nucleotide polymorphisms (SNPs) in 321 pulmonary TB cases...

  13. Measuring multifactor productivity growth

    Czech Academy of Sciences Publication Activity Database

    Wölfl, A.; Hájková, Dana

    -, 2007/5 (2007), s. 1-45 Institutional research plan: CEZ:AV0Z70850503 Keywords : multifactor productivity growth * GDP growth * measuring Subject RIV: AH - Economics http://www.oecd.org/dataoecd/61/17/39522985.pdf

  14. Multi-factor authentication

    Science.gov (United States)

    Hamlet, Jason R; Pierson, Lyndon G

    2014-10-21

    Detection and deterrence of spoofing of user authentication may be achieved by including a cryptographic fingerprint unit within a hardware device for authenticating a user of the hardware device. The cryptographic fingerprint unit includes an internal physically unclonable function ("PUF") circuit disposed in or on the hardware device, which generates a PUF value. Combining logic is coupled to receive the PUF value, combines the PUF value with one or more other authentication factors to generate a multi-factor authentication value. A key generator is coupled to generate a private key and a public key based on the multi-factor authentication value while a decryptor is coupled to receive an authentication challenge posed to the hardware device and encrypted with the public key and coupled to output a response to the authentication challenge decrypted with the private key.

  15. Reduction of infinite dimensional equations

    Directory of Open Access Journals (Sweden)

    Zhongding Li

    2006-02-01

    Full Text Available In this paper, we use the general Legendre transformation to show the infinite dimensional integrable equations can be reduced to a finite dimensional integrable Hamiltonian system on an invariant set under the flow of the integrable equations. Then we obtain the periodic or quasi-periodic solution of the equation. This generalizes the results of Lax and Novikov regarding the periodic or quasi-periodic solution of the KdV equation to the general case of isospectral Hamiltonian integrable equation. And finally, we discuss the AKNS hierarchy as a special example.

  16. The dimensional reduction in a multi-dimensional cosmology

    International Nuclear Information System (INIS)

    Demianski, M.; Golda, Z.A.; Heller, M.; Szydlowski, M.

    1986-01-01

    Einstein's field equations are solved for the case of the eleven-dimensional vacuum spacetime which is the product R x Bianchi V x T 7 , where T 7 is a seven-dimensional torus. Among all possible solutions, the authors identify those in which the macroscopic space expands and the microscopic space contracts to a finite size. The solutions with this property are 'typical' within the considered class. They implement the idea of a purely dynamical dimensional reduction. (author)

  17. Coset space dimensional reduction of gauge theories

    Energy Technology Data Exchange (ETDEWEB)

    Kapetanakis, D. (Physik Dept., Technische Univ. Muenchen, Garching (Germany)); Zoupanos, G. (CERN, Geneva (Switzerland))

    1992-10-01

    We review the attempts to construct unified theories defined in higher dimensions which are dimensionally reduced over coset spaces. We employ the coset space dimensional reduction scheme, which permits the detailed study of the resulting four-dimensional gauge theories. In the context of this scheme we present the difficulties and the suggested ways out in the attempts to describe the observed interactions in a realistic way. (orig.).

  18. Coset space dimensional reduction of gauge theories

    International Nuclear Information System (INIS)

    Kapetanakis, D.; Zoupanos, G.

    1992-01-01

    We review the attempts to construct unified theories defined in higher dimensions which are dimensionally reduced over coset spaces. We employ the coset space dimensional reduction scheme, which permits the detailed study of the resulting four-dimensional gauge theories. In the context of this scheme we present the difficulties and the suggested ways out in the attempts to describe the observed interactions in a realistic way. (orig.)

  19. Central subspace dimensionality reduction using covariance operators.

    Science.gov (United States)

    Kim, Minyoung; Pavlovic, Vladimir

    2011-04-01

    We consider the task of dimensionality reduction informed by real-valued multivariate labels. The problem is often treated as Dimensionality Reduction for Regression (DRR), whose goal is to find a low-dimensional representation, the central subspace, of the input data that preserves the statistical correlation with the targets. A class of DRR methods exploits the notion of inverse regression (IR) to discover central subspaces. Whereas most existing IR techniques rely on explicit output space slicing, we propose a novel method called the Covariance Operator Inverse Regression (COIR) that generalizes IR to nonlinear input/output spaces without explicit target slicing. COIR's unique properties make DRR applicable to problem domains with high-dimensional output data corrupted by potentially significant amounts of noise. Unlike recent kernel dimensionality reduction methods that employ iterative nonconvex optimization, COIR yields a closed-form solution. We also establish the link between COIR, other DRR techniques, and popular supervised dimensionality reduction methods, including canonical correlation analysis and linear discriminant analysis. We then extend COIR to semi-supervised settings where many of the input points lack their labels. We demonstrate the benefits of COIR on several important regression problems in both fully supervised and semi-supervised settings.

  20. Dimensional reduction of a generalized flux problem

    International Nuclear Information System (INIS)

    Moroz, A.

    1992-01-01

    In this paper, a generalized flux problem with Abelian and non-Abelian fluxes is considered. In the Abelian case we shall show that the generalized flux problem for tight-binding models of noninteracting electrons on either 2n- or (2n + 1)-dimensional lattice can always be reduced to an n-dimensional hopping problem. A residual freedom in this reduction enables one to identify equivalence classes of hopping Hamiltonians which have the same spectrum. In the non-Abelian case, the reduction is not possible in general unless the flux tensor factorizes into an Abelian one times are element of the corresponding algebra

  1. Multichannel transfer function with dimensionality reduction

    KAUST Repository

    Kim, Han Suk

    2010-01-17

    The design of transfer functions for volume rendering is a difficult task. This is particularly true for multi-channel data sets, where multiple data values exist for each voxel. In this paper, we propose a new method for transfer function design. Our new method provides a framework to combine multiple approaches and pushes the boundary of gradient-based transfer functions to multiple channels, while still keeping the dimensionality of transfer functions to a manageable level, i.e., a maximum of three dimensions, which can be displayed visually in a straightforward way. Our approach utilizes channel intensity, gradient, curvature and texture properties of each voxel. The high-dimensional data of the domain is reduced by applying recently developed nonlinear dimensionality reduction algorithms. In this paper, we used Isomap as well as a traditional algorithm, Principle Component Analysis (PCA). Our results show that these dimensionality reduction algorithms significantly improve the transfer function design process without compromising visualization accuracy. In this publication we report on the impact of the dimensionality reduction algorithms on transfer function design for confocal microscopy data.

  2. Pole masses of quarks in dimensional reduction

    International Nuclear Information System (INIS)

    Avdeev, L.V.; Kalmykov, M.Yu.

    1997-01-01

    Pole masses of quarks in quantum chromodynamics are calculated to the two-loop order in the framework of the regularization by dimensional reduction. For the diagram with a light quark loop, the non-Euclidean asymptotic expansion is constructed with the external momentum on the mass shell of a heavy quark

  3. General dimensional reduction of ten-dimensional supergravity and superstring

    International Nuclear Information System (INIS)

    Ferrara, S.; Porrati, M.

    1986-01-01

    Dimensional reductions of supergravity theories are shown to yield to specific glasses of four-dimensional no-scale models with N=4, 2 or 1 residual supersymmetry. N=1 ''maximal'' supergravity lagrangian, corresponding to the ''untwisted'' sector of orbifold compactification of superstrings, contains nine families and has a no-scale structure based on the Kaehler manifold [SU(3, 3+3n)/SU(3)xSU(3+3n)]x[SU(1, 1)/U(1)]. The quantum consistency of the resulting theories give information on the non Kaluza-Klein (string) ''twisted'' sector. (orig.)

  4. Dimensionality reduction with unsupervised nearest neighbors

    CERN Document Server

    Kramer, Oliver

    2013-01-01

    This book is devoted to a novel approach for dimensionality reduction based on the famous nearest neighbor method that is a powerful classification and regression approach. It starts with an introduction to machine learning concepts and a real-world application from the energy domain. Then, unsupervised nearest neighbors (UNN) is introduced as efficient iterative method for dimensionality reduction. Various UNN models are developed step by step, reaching from a simple iterative strategy for discrete latent spaces to a stochastic kernel-based algorithm for learning submanifolds with independent parameterizations. Extensions that allow the embedding of incomplete and noisy patterns are introduced. Various optimization approaches are compared, from evolutionary to swarm-based heuristics. Experimental comparisons to related methodologies taking into account artificial test data sets and also real-world data demonstrate the behavior of UNN in practical scenarios. The book contains numerous color figures to illustr...

  5. Dimensional reduction from entanglement in Minkowski space

    International Nuclear Information System (INIS)

    Brustein, Ram; Yarom, Amos

    2005-01-01

    Using a quantum field theoretic setting, we present evidence for dimensional reduction of any sub-volume of Minkowksi space. First, we show that correlation functions of a class of operators restricted to a sub-volume of D-dimensional Minkowski space scale as its surface area. A simple example of such area scaling is provided by the energy fluctuations of a free massless quantum field in its vacuum state. This is reminiscent of area scaling of entanglement entropy but applies to quantum expectation values in a pure state, rather than to statistical averages over a mixed state. We then show, in a specific case, that fluctuations in the bulk have a lower-dimensional representation in terms of a boundary theory at high temperature. (author)

  6. Photon-counting multifactor optical encryption and authentication

    International Nuclear Information System (INIS)

    Pérez-Cabré, E; Millán, M S; Mohammed, E A; Saadon, H L

    2015-01-01

    The multifactor optical encryption authentication method [Opt. Lett., 31 721-3 (2006)] reinforces optical security by allowing the simultaneous authentication of up to four factors. In this work, the photon-counting imaging technique is applied to the multifactor encrypted function so that a sparse phase-only distribution is generated for the encrypted data. The integration of both techniques permits an increased capacity for signal hiding with simultaneous data reduction for better fulfilling the general requirements of protection, storage and transmission. Cryptanalysis of the proposed method is carried out in terms of chosen-plaintext and chosen-ciphertext attacks. Although the multifactor authentication process is not substantially altered by those attacks, its integration with the photon-counting imaging technique prevents from possible partial disclosure of any encrypted factor, thus increasing the security level of the overall process. Numerical experiments and results are provided and discussed. (paper)

  7. Dimensional reduction for D3-brane moduli

    International Nuclear Information System (INIS)

    Cownden, Brad; Frey, Andrew R.; Marsh, M.C. David; Underwood, Bret

    2016-01-01

    Warped string compactifications are central to many attempts to stabilize moduli and connect string theory with cosmology and particle phenomenology. We present a first-principles derivation of the low-energy 4D effective theory from dimensional reduction of a D3-brane in a warped Calabi-Yau compactification of type IIB string theory with imaginary self-dual 3-form flux, including effects of D3-brane motion beyond the probe approximation, and find the metric on the moduli space of brane positions, the universal volume modulus, and axions descending from the 4-form potential. As D3-branes may be considered as carrying either electric or magnetic charges for the self-dual 5-form field strength, we present calculations in both duality frames. Our results are consistent with, but extend significantly, earlier results on the low-energy effective theory arising from D3-branes in string compactifications.

  8. Denoising and dimensionality reduction of genomic data

    Science.gov (United States)

    Capobianco, Enrico

    2005-05-01

    Genomics represents a challenging research field for many quantitative scientists, and recently a vast variety of statistical techniques and machine learning algorithms have been proposed and inspired by cross-disciplinary work with computational and systems biologists. In genomic applications, the researcher deals with noisy and complex high-dimensional feature spaces; a wealth of genes whose expression levels are experimentally measured, can often be observed for just a few time points, thus limiting the available samples. This unbalanced combination suggests that it might be hard for standard statistical inference techniques to come up with good general solutions, likewise for machine learning algorithms to avoid heavy computational work. Thus, one naturally turns to two major aspects of the problem: sparsity and intrinsic dimensionality. These two aspects are studied in this paper, where for both denoising and dimensionality reduction, a very efficient technique, i.e., Independent Component Analysis, is used. The numerical results are very promising, and lead to a very good quality of gene feature selection, due to the signal separation power enabled by the decomposition technique. We investigate how the use of replicates can improve these results, and deal with noise through a stabilization strategy which combines the estimated components and extracts the most informative biological information from them. Exploiting the inherent level of sparsity is a key issue in genetic regulatory networks, where the connectivity matrix needs to account for the real links among genes and discard many redundancies. Most experimental evidence suggests that real gene-gene connections represent indeed a subset of what is usually mapped onto either a huge gene vector or a typically dense and highly structured network. Inferring gene network connectivity from the expression levels represents a challenging inverse problem that is at present stimulating key research in biomedical

  9. Cosmological string solutions by dimensional reduction

    International Nuclear Information System (INIS)

    Behrndt, K.; Foerste, S.

    1993-12-01

    We obtain cosmological four dimensional solutions of the low energy effective string theory by reducing a five dimensional black hole, and black hole-de Sitter solution of the Einstein gravity down to four dimensions. The appearance of a cosmological constant in the five dimensional Einstein-Hilbert produces a special dilaton potential in the four dimensional effective string action. Cosmological scenarios implement by our solutions are discussed

  10. Discrete symmetries and coset space dimensional reduction

    International Nuclear Information System (INIS)

    Kapetanakis, D.; Zoupanos, G.

    1989-01-01

    We consider the discrete symmetries of all the six-dimensional coset spaces and we apply them in gauge theories defined in ten dimensions which are dimensionally reduced over these homogeneous spaces. Particular emphasis is given in the consequences of the discrete symmetries on the particle content as well as on the symmetry breaking a la Hosotani of the resulting four-dimensional theory. (orig.)

  11. On dimensional reduction over coset spaces

    International Nuclear Information System (INIS)

    Kapetanakis, D.; Zoupanos, G.

    1990-01-01

    Gauge theories defined in higher dimensions can be dimensionally reduced over coset spaces giving definite predictions for the resulting four-dimensional theory. We present the most interesting features of these theories as well as an attempt to construct a model with realistic low energy behaviour within this framework. (author)

  12. Multichannel transfer function with dimensionality reduction

    KAUST Repository

    Kim, Han Suk; Schulze, Jü rgen P.; Cone, Angela C.; Sosinsky, Gina E.; Martone, Maryann E.

    2010-01-01

    . Our new method provides a framework to combine multiple approaches and pushes the boundary of gradient-based transfer functions to multiple channels, while still keeping the dimensionality of transfer functions to a manageable level, i.e., a maximum

  13. Dimensionality reduction of collective motion by principal manifolds

    Science.gov (United States)

    Gajamannage, Kelum; Butail, Sachit; Porfiri, Maurizio; Bollt, Erik M.

    2015-01-01

    While the existence of low-dimensional embedding manifolds has been shown in patterns of collective motion, the current battery of nonlinear dimensionality reduction methods is not amenable to the analysis of such manifolds. This is mainly due to the necessary spectral decomposition step, which limits control over the mapping from the original high-dimensional space to the embedding space. Here, we propose an alternative approach that demands a two-dimensional embedding which topologically summarizes the high-dimensional data. In this sense, our approach is closely related to the construction of one-dimensional principal curves that minimize orthogonal error to data points subject to smoothness constraints. Specifically, we construct a two-dimensional principal manifold directly in the high-dimensional space using cubic smoothing splines, and define the embedding coordinates in terms of geodesic distances. Thus, the mapping from the high-dimensional data to the manifold is defined in terms of local coordinates. Through representative examples, we show that compared to existing nonlinear dimensionality reduction methods, the principal manifold retains the original structure even in noisy and sparse datasets. The principal manifold finding algorithm is applied to configurations obtained from a dynamical system of multiple agents simulating a complex maneuver called predator mobbing, and the resulting two-dimensional embedding is compared with that of a well-established nonlinear dimensionality reduction method.

  14. Stochastic confinement and dimensional reduction. 1

    International Nuclear Information System (INIS)

    Ambjoern, J.; Olesen, P.; Peterson, C.

    1984-03-01

    By Monte Carlo calculations on a 16 4 lattice the authors investigate four dimensional SU(2) lattice guage theory with respect to the conjecture that at large distances this theory reduces approximately to two dimensional SU(2) lattice gauge theory. Good numerical evidence is found for this conjecture. As a by-product the SU(2) string tension is also measured and good agreement is found with scaling. The 'adjoint string tension' is also found to have a reasonable scaling behaviour. (Auth.)

  15. Stochastic confinement and dimensional reduction. Pt. 1

    International Nuclear Information System (INIS)

    Ambjoern, J.; Olesen, P.; Peterson, C.

    1984-01-01

    By Monte Carlo calculations on a 12 4 lattice we investigate four-dimensional SU(2) lattice gauge theory with respect to the conjecture that at large distances this theory reduces approximately to two-dimensional SU(2) lattice gauge theory. We find good numerical evidence for this conjecture. As a by-product we also measure the SU(2) string tension and find reasonable agreement with scaling. The 'adjoint string tension' is also found to have a reasonable scaling behaviour. (orig.)

  16. A Guide to the Multifactored Evaluation (MFE).

    Science.gov (United States)

    Ohio Coalition for the Education of Children with Disabilities, Marion.

    This guide provides Ohio parents of children with disabilities with information on multifactored evaluations. It begins by discussing the Intervention Assistance Team and what occurs at the assistance team meeting. It also explains that to begin the multifactored evaluation process, the parent must complete a "Request for Parent Consent for…

  17. Parallel Framework for Dimensionality Reduction of Large-Scale Datasets

    Directory of Open Access Journals (Sweden)

    Sai Kiranmayee Samudrala

    2015-01-01

    Full Text Available Dimensionality reduction refers to a set of mathematical techniques used to reduce complexity of the original high-dimensional data, while preserving its selected properties. Improvements in simulation strategies and experimental data collection methods are resulting in a deluge of heterogeneous and high-dimensional data, which often makes dimensionality reduction the only viable way to gain qualitative and quantitative understanding of the data. However, existing dimensionality reduction software often does not scale to datasets arising in real-life applications, which may consist of thousands of points with millions of dimensions. In this paper, we propose a parallel framework for dimensionality reduction of large-scale data. We identify key components underlying the spectral dimensionality reduction techniques, and propose their efficient parallel implementation. We show that the resulting framework can be used to process datasets consisting of millions of points when executed on a 16,000-core cluster, which is beyond the reach of currently available methods. To further demonstrate applicability of our framework we perform dimensionality reduction of 75,000 images representing morphology evolution during manufacturing of organic solar cells in order to identify how processing parameters affect morphology evolution.

  18. Fukunaga-Koontz transform based dimensionality reduction for hyperspectral imagery

    Science.gov (United States)

    Ochilov, S.; Alam, M. S.; Bal, A.

    2006-05-01

    Fukunaga-Koontz Transform based technique offers some attractive properties for desired class oriented dimensionality reduction in hyperspectral imagery. In FKT, feature selection is performed by transforming into a new space where feature classes have complimentary eigenvectors. Dimensionality reduction technique based on these complimentary eigenvector analysis can be described under two classes, desired class and background clutter, such that each basis function best represent one class while carrying the least amount of information from the second class. By selecting a few eigenvectors which are most relevant to desired class, one can reduce the dimension of hyperspectral cube. Since the FKT based technique reduces data size, it provides significant advantages for near real time detection applications in hyperspectral imagery. Furthermore, the eigenvector selection approach significantly reduces computation burden via the dimensionality reduction processes. The performance of the proposed dimensionality reduction algorithm has been tested using real-world hyperspectral dataset.

  19. Dimensional reduction near the deconfinement transition

    International Nuclear Information System (INIS)

    Kurkela, A.

    2009-01-01

    It is expected that incorporating the center symmetry in the conventional dimensionally reduced effective theory for high-temperature SU(N) Yang-Mills theory, EQCD, will considerably extend its applicability towards the deconfinement transition. In this talk, I will discuss the construction of such center-symmetric effective theories and present results from their lattice simulations in the case of two colors. The simulations demonstrate that unlike EQCD, the new center symmetric theory undergoes a second order confining phase transition in complete analogy with the full theory. I will also describe the perturbative and non-perturbative matching of the parameters of the effective theory, and outline ways to further improve its description of the physics near the deconfinement transition. (author)

  20. Dimensionality reduction of quality of life indicators

    Directory of Open Access Journals (Sweden)

    Andrea Jindrová

    2012-01-01

    Full Text Available Selecting indicators for assessing the quality of life at the regional level is not unambigous. Currently, there are no precisely defined indicators that would give comprehensive information about the quality of life on a local level. In this paper we focus on the determination (selection of groups of indicators that can be interpreted, on the basis of studied literature, as factors characterizing the quality of life. Furthermore, on the application of methods to reduce the dimensionality of these indicators, from the source of the database CULS KROK, which provides statistics on the regional and districts level. To reduce the number of indicators and the subsequent creation of derived variables that capture the relationships between selected indicators multivariate statistical analysis methods, especially method of principal components and factor analysis were used. This paper also indicates the methodology grant project “Methodological Approaches to assess Subjective Aspects of the life quality in regions of the Czech Republic”.

  1. Method of dimensionality reduction in contact mechanics and friction

    CERN Document Server

    Popov, Valentin L

    2015-01-01

    This book describes for the first time a simulation method for the fast calculation of contact properties and friction between rough surfaces in a complete form. In contrast to existing simulation methods, the method of dimensionality reduction (MDR) is based on the exact mapping of various types of three-dimensional contact problems onto contacts of one-dimensional foundations. Within the confines of MDR, not only are three dimensional systems reduced to one-dimensional, but also the resulting degrees of freedom are independent from another. Therefore, MDR results in an enormous reduction of the development time for the numerical implementation of contact problems as well as the direct computation time and can ultimately assume a similar role in tribology as FEM has in structure mechanics or CFD methods, in hydrodynamics. Furthermore, it substantially simplifies analytical calculation and presents a sort of “pocket book edition” of the entirety contact mechanics. Measurements of the rheology of bodies in...

  2. Metric dimensional reduction at singularities with implications to Quantum Gravity

    International Nuclear Information System (INIS)

    Stoica, Ovidiu Cristinel

    2014-01-01

    A series of old and recent theoretical observations suggests that the quantization of gravity would be feasible, and some problems of Quantum Field Theory would go away if, somehow, the spacetime would undergo a dimensional reduction at high energy scales. But an identification of the deep mechanism causing this dimensional reduction would still be desirable. The main contribution of this article is to show that dimensional reduction effects are due to General Relativity at singularities, and do not need to be postulated ad-hoc. Recent advances in understanding the geometry of singularities do not require modification of General Relativity, being just non-singular extensions of its mathematics to the limit cases. They turn out to work fine for some known types of cosmological singularities (black holes and FLRW Big-Bang), allowing a choice of the fundamental geometric invariants and physical quantities which remain regular. The resulting equations are equivalent to the standard ones outside the singularities. One consequence of this mathematical approach to the singularities in General Relativity is a special, (geo)metric type of dimensional reduction: at singularities, the metric tensor becomes degenerate in certain spacetime directions, and some properties of the fields become independent of those directions. Effectively, it is like one or more dimensions of spacetime just vanish at singularities. This suggests that it is worth exploring the possibility that the geometry of singularities leads naturally to the spontaneous dimensional reduction needed by Quantum Gravity. - Highlights: • The singularities we introduce are described by finite geometric/physical objects. • Our singularities are accompanied by dimensional reduction effects. • They affect the metric, the measure, the topology, the gravitational DOF (Weyl = 0). • Effects proposed in other approaches to Quantum Gravity are obtained naturally. • The geometric dimensional reduction obtained

  3. Multi-factor authentication using quantum communication

    Science.gov (United States)

    Hughes, Richard John; Peterson, Charles Glen; Thrasher, James T.; Nordholt, Jane E.; Yard, Jon T.; Newell, Raymond Thorson; Somma, Rolando D.

    2018-02-06

    Multi-factor authentication using quantum communication ("QC") includes stages for enrollment and identification. For example, a user enrolls for multi-factor authentication that uses QC with a trusted authority. The trusted authority transmits device factor information associated with a user device (such as a hash function) and user factor information associated with the user (such as an encrypted version of a user password). The user device receives and stores the device factor information and user factor information. For multi-factor authentication that uses QC, the user device retrieves its stored device factor information and user factor information, then transmits the user factor information to the trusted authority, which also retrieves its stored device factor information. The user device and trusted authority use the device factor information and user factor information (more specifically, information such as a user password that is the basis of the user factor information) in multi-factor authentication that uses QC.

  4. Effective Image Database Search via Dimensionality Reduction

    DEFF Research Database (Denmark)

    Dahl, Anders Bjorholm; Aanæs, Henrik

    2008-01-01

    Image search using the bag-of-words image representation is investigated further in this paper. This approach has shown promising results for large scale image collections making it relevant for Internet applications. The steps involved in the bag-of-words approach are feature extraction, vocabul......Image search using the bag-of-words image representation is investigated further in this paper. This approach has shown promising results for large scale image collections making it relevant for Internet applications. The steps involved in the bag-of-words approach are feature extraction......, vocabulary building, and searching with a query image. It is important to keep the computational cost low through all steps. In this paper we focus on the efficiency of the technique. To do that we substantially reduce the dimensionality of the features by the use of PCA and addition of color. Building...... of the visual vocabulary is typically done using k-means. We investigate a clustering algorithm based on the leader follower principle (LF-clustering), in which the number of clusters is not fixed. The adaptive nature of LF-clustering is shown to improve the quality of the visual vocabulary using this...

  5. Adaptive Sampling for Nonlinear Dimensionality Reduction Based on Manifold Learning

    DEFF Research Database (Denmark)

    Franz, Thomas; Zimmermann, Ralf; Goertz, Stefan

    2017-01-01

    We make use of the non-intrusive dimensionality reduction method Isomap in order to emulate nonlinear parametric flow problems that are governed by the Reynolds-averaged Navier-Stokes equations. Isomap is a manifold learning approach that provides a low-dimensional embedding space that is approxi...... to detect and fill up gaps in the sampling in the embedding space. The performance of the proposed manifold filling method will be illustrated by numerical experiments, where we consider nonlinear parameter-dependent steady-state Navier-Stokes flows in the transonic regime.......We make use of the non-intrusive dimensionality reduction method Isomap in order to emulate nonlinear parametric flow problems that are governed by the Reynolds-averaged Navier-Stokes equations. Isomap is a manifold learning approach that provides a low-dimensional embedding space...

  6. A Tannakian approach to dimensional reduction of principal bundles

    Science.gov (United States)

    Álvarez-Cónsul, Luis; Biswas, Indranil; García-Prada, Oscar

    2017-08-01

    Let P be a parabolic subgroup of a connected simply connected complex semisimple Lie group G. Given a compact Kähler manifold X, the dimensional reduction of G-equivariant holomorphic vector bundles over X × G / P was carried out in Álvarez-Cónsul and García-Prada (2003). This raises the question of dimensional reduction of holomorphic principal bundles over X × G / P. The method of Álvarez-Cónsul and García-Prada (2003) is special to vector bundles; it does not generalize to principal bundles. In this paper, we adapt to equivariant principal bundles the Tannakian approach of Nori, to describe the dimensional reduction of G-equivariant principal bundles over X × G / P, and to establish a Hitchin-Kobayashi type correspondence. In order to be able to apply the Tannakian theory, we need to assume that X is a complex projective manifold.

  7. Construction of N=8 supergravity theories by dimensional reduction

    International Nuclear Information System (INIS)

    Boucher, W.

    1985-01-01

    In this paper I ask which N=8 supergravity theories in four dimensions can be obtained by dimensional reduction of the N=1 supergravity theory in eleven dimensions. Several years ago Scherk and Schwarz produced a particular class of N = 8 theories by giving a dimensional reduction scheme on the restricted class of coset spaces, G/H, with dim H=0 (and therefore dim G=7). I generalize their considerations by looking at arbitrary (seven-dimensional) coset spaces. Also, instead of giving a particular ansatz which happens to work, I set about the distinctly more difficult task of determining all ansatzes which produce N=8 theories. The basic ingredient of my dimensional reduction scheme is the demand that certain symmetries, including supersymmetry, be truncated consistently. I find the surprising result that the only N=8 theories obtainable within the contexts of my scheme are those theories already written down by Scherk and Schwarz. In particular dim H=0 and dim G=7. Independently of these considerations, I prove that any dimensional reduction scheme which consistently truncates supersymmetry must also be consistent with the equations of motion. I discuss Lorentz-invariant solutions of the theories of Scherk and Schwarz, pointing out that since the ansatz of Scherk and Schwarz consistently truncates supersymmetry, any solution of these theories is also a solution of the N=1 supergravity theory in eleven dimensions and, hence, in particular that there is a Freund-Rubin-type ansatz for these theories. However I demonstrate that for most gauge groups the ansatz must be trivial which implies that for these theories the cosmological constant of any Lorentz-invariant solution must be zero (classically). Finally, I make some comparisons with work by Manton on dimensional reduction. (orig.)

  8. Nonlinear dimensionality reduction methods for synthetic biology biobricks' visualization.

    Science.gov (United States)

    Yang, Jiaoyun; Wang, Haipeng; Ding, Huitong; An, Ning; Alterovitz, Gil

    2017-01-19

    Visualizing data by dimensionality reduction is an important strategy in Bioinformatics, which could help to discover hidden data properties and detect data quality issues, e.g. data noise, inappropriately labeled data, etc. As crowdsourcing-based synthetic biology databases face similar data quality issues, we propose to visualize biobricks to tackle them. However, existing dimensionality reduction methods could not be directly applied on biobricks datasets. Hereby, we use normalized edit distance to enhance dimensionality reduction methods, including Isomap and Laplacian Eigenmaps. By extracting biobricks from synthetic biology database Registry of Standard Biological Parts, six combinations of various types of biobricks are tested. The visualization graphs illustrate discriminated biobricks and inappropriately labeled biobricks. Clustering algorithm K-means is adopted to quantify the reduction results. The average clustering accuracy for Isomap and Laplacian Eigenmaps are 0.857 and 0.844, respectively. Besides, Laplacian Eigenmaps is 5 times faster than Isomap, and its visualization graph is more concentrated to discriminate biobricks. By combining normalized edit distance with Isomap and Laplacian Eigenmaps, synthetic biology biobircks are successfully visualized in two dimensional space. Various types of biobricks could be discriminated and inappropriately labeled biobricks could be determined, which could help to assess crowdsourcing-based synthetic biology databases' quality, and make biobricks selection.

  9. Perturbative QCD lagrangian at large distances and stochastic dimensionality reduction

    International Nuclear Information System (INIS)

    Shintani, M.

    1986-10-01

    We construct a Lagrangian for perturbative QCD at large distances within the covariant operator formalism which explains the color confinement of quarks and gluons while maintaining unitarity of the S-matrix. It is also shown that when interactions are switched off, the mechanism of stochastic dimensionality reduction is operative in the system due to exact super-Lorentz symmetries. (orig.)

  10. TPSLVM: a dimensionality reduction algorithm based on thin plate splines.

    Science.gov (United States)

    Jiang, Xinwei; Gao, Junbin; Wang, Tianjiang; Shi, Daming

    2014-10-01

    Dimensionality reduction (DR) has been considered as one of the most significant tools for data analysis. One type of DR algorithms is based on latent variable models (LVM). LVM-based models can handle the preimage problem easily. In this paper we propose a new LVM-based DR model, named thin plate spline latent variable model (TPSLVM). Compared to the well-known Gaussian process latent variable model (GPLVM), our proposed TPSLVM is more powerful especially when the dimensionality of the latent space is low. Also, TPSLVM is robust to shift and rotation. This paper investigates two extensions of TPSLVM, i.e., the back-constrained TPSLVM (BC-TPSLVM) and TPSLVM with dynamics (TPSLVM-DM) as well as their combination BC-TPSLVM-DM. Experimental results show that TPSLVM and its extensions provide better data visualization and more efficient dimensionality reduction compared to PCA, GPLVM, ISOMAP, etc.

  11. N-Dimensional LLL Reduction Algorithm with Pivoted Reflection

    Directory of Open Access Journals (Sweden)

    Zhongliang Deng

    2018-01-01

    Full Text Available The Lenstra-Lenstra-Lovász (LLL lattice reduction algorithm and many of its variants have been widely used by cryptography, multiple-input-multiple-output (MIMO communication systems and carrier phase positioning in global navigation satellite system (GNSS to solve the integer least squares (ILS problem. In this paper, we propose an n-dimensional LLL reduction algorithm (n-LLL, expanding the Lovász condition in LLL algorithm to n-dimensional space in order to obtain a further reduced basis. We also introduce pivoted Householder reflection into the algorithm to optimize the reduction time. For an m-order positive definite matrix, analysis shows that the n-LLL reduction algorithm will converge within finite steps and always produce better results than the original LLL reduction algorithm with n > 2. The simulations clearly prove that n-LLL is better than the original LLL in reducing the condition number of an ill-conditioned input matrix with 39% improvement on average for typical cases, which can significantly reduce the searching space for solving ILS problem. The simulation results also show that the pivoted reflection has significantly declined the number of swaps in the algorithm by 57%, making n-LLL a more practical reduction algorithm.

  12. Superfluid hydrodynamics of polytropic gases: dimensional reduction and sound velocity

    International Nuclear Information System (INIS)

    Bellomo, N; Mazzarella, G; Salasnich, L

    2014-01-01

    Motivated by the fact that two-component confined fermionic gases in Bardeen–Cooper–Schrieffer–Bose–Einstein condensate (BCS–BEC) crossover can be described through an hydrodynamical approach, we study these systems—both in the cigar-shaped configuration and in the disc-shaped one—by using a polytropic Lagrangian density. We start from the Popov Lagrangian density and obtain, after a dimensional reduction process, the equations that control the dynamics of such systems. By solving these equations we study the sound velocity as a function of the density by analyzing how the dimensionality affects this velocity. (paper)

  13. A sparse grid based method for generative dimensionality reduction of high-dimensional data

    Science.gov (United States)

    Bohn, Bastian; Garcke, Jochen; Griebel, Michael

    2016-03-01

    Generative dimensionality reduction methods play an important role in machine learning applications because they construct an explicit mapping from a low-dimensional space to the high-dimensional data space. We discuss a general framework to describe generative dimensionality reduction methods, where the main focus lies on a regularized principal manifold learning variant. Since most generative dimensionality reduction algorithms exploit the representer theorem for reproducing kernel Hilbert spaces, their computational costs grow at least quadratically in the number n of data. Instead, we introduce a grid-based discretization approach which automatically scales just linearly in n. To circumvent the curse of dimensionality of full tensor product grids, we use the concept of sparse grids. Furthermore, in real-world applications, some embedding directions are usually more important than others and it is reasonable to refine the underlying discretization space only in these directions. To this end, we employ a dimension-adaptive algorithm which is based on the ANOVA (analysis of variance) decomposition of a function. In particular, the reconstruction error is used to measure the quality of an embedding. As an application, the study of large simulation data from an engineering application in the automotive industry (car crash simulation) is performed.

  14. Kantowski-Sachs multidimensional cosmological models and dynamical dimensional reduction

    International Nuclear Information System (INIS)

    Demianski, M.; Rome Univ.; Golda, Z.A.; Heller, M.; Szydlowski, M.

    1988-01-01

    Einstein's field equations are solved for a multidimensional spacetime (KS) x Tsup(m), where (KS) is a four-dimensional Kantowski-Sachs spacetime and Tsup(m) is an m-dimensional torus. Among all possible vacuum solutions there is a large class of spacetimes in which the macroscopic space expands and the microscopic space contracts to a finite volume. We also consider a non-vacuum case and we explicitly solve the field equations for the matter satisfying the Zel'dovich equation of state. In non-vacuum models, with matter satisfying an equation of state p = γρ, O ≤ γ < 1, at a sufficiently late stage of evolution the microspace always expands and the dynamical dimensional reduction does not occur. (author)

  15. One-loop dimensional reduction of the linear σ model

    International Nuclear Information System (INIS)

    Malbouisson, A.P.C.; Silva-Neto, M.B.; Svaiter, N.F.

    1997-05-01

    We perform the dimensional reduction of the linear σ model at one-loop level. The effective of the reduced theory obtained from the integration over the nonzero Matsubara frequencies is exhibited. Thermal mass and coupling constant renormalization constants are given, as well as the thermal renormalization group which controls the dependence of the counterterms on the temperature. We also recover, for the reduced theory, the vacuum instability of the model for large N. (author)

  16. Multifactor Authentication: Its Time Has Come

    Directory of Open Access Journals (Sweden)

    Jim Reno

    2013-08-01

    Full Text Available Transactions of any value must be authenticated to help prevent online crime. Even seemingly innocent interactions, such as social media postings, can have serious consequences if used fraudulently. A key problem in modern online interactions is establishing the identity of the user without alienating the user. Historically, almost all online authentications have been implemented using simple passwords, but increasingly these methods are under attack. Multifactor authentication requires the presentation of two or more of the three authentication factor types: “What you know”, “What you have”, and “What you are”. After presentation, each factor must be validated by the other party for authentication to occur. Multifactor authentication is a potential solution to the authentication problem, and it is beginning to be implemented at websites operated by well-known companies. This article surveys the different mechanisms used to implement multifactor authentication. How a site chooses to implement multifactor authentication affects security as well as the overall user experience.

  17. Dimensional Reduction for the General Markov Model on Phylogenetic Trees.

    Science.gov (United States)

    Sumner, Jeremy G

    2017-03-01

    We present a method of dimensional reduction for the general Markov model of sequence evolution on a phylogenetic tree. We show that taking certain linear combinations of the associated random variables (site pattern counts) reduces the dimensionality of the model from exponential in the number of extant taxa, to quadratic in the number of taxa, while retaining the ability to statistically identify phylogenetic divergence events. A key feature is the identification of an invariant subspace which depends only bilinearly on the model parameters, in contrast to the usual multi-linear dependence in the full space. We discuss potential applications including the computation of split (edge) weights on phylogenetic trees from observed sequence data.

  18. Kernel Based Nonlinear Dimensionality Reduction and Classification for Genomic Microarray

    Directory of Open Access Journals (Sweden)

    Lan Shu

    2008-07-01

    Full Text Available Genomic microarrays are powerful research tools in bioinformatics and modern medicinal research because they enable massively-parallel assays and simultaneous monitoring of thousands of gene expression of biological samples. However, a simple microarray experiment often leads to very high-dimensional data and a huge amount of information, the vast amount of data challenges researchers into extracting the important features and reducing the high dimensionality. In this paper, a nonlinear dimensionality reduction kernel method based locally linear embedding(LLE is proposed, and fuzzy K-nearest neighbors algorithm which denoises datasets will be introduced as a replacement to the classical LLE’s KNN algorithm. In addition, kernel method based support vector machine (SVM will be used to classify genomic microarray data sets in this paper. We demonstrate the application of the techniques to two published DNA microarray data sets. The experimental results confirm the superiority and high success rates of the presented method.

  19. Supervised linear dimensionality reduction with robust margins for object recognition

    Science.gov (United States)

    Dornaika, F.; Assoum, A.

    2013-01-01

    Linear Dimensionality Reduction (LDR) techniques have been increasingly important in computer vision and pattern recognition since they permit a relatively simple mapping of data onto a lower dimensional subspace, leading to simple and computationally efficient classification strategies. Recently, many linear discriminant methods have been developed in order to reduce the dimensionality of visual data and to enhance the discrimination between different groups or classes. Many existing linear embedding techniques relied on the use of local margins in order to get a good discrimination performance. However, dealing with outliers and within-class diversity has not been addressed by margin-based embedding method. In this paper, we explored the use of different margin-based linear embedding methods. More precisely, we propose to use the concepts of Median miss and Median hit for building robust margin-based criteria. Based on such margins, we seek the projection directions (linear embedding) such that the sum of local margins is maximized. Our proposed approach has been applied to the problem of appearance-based face recognition. Experiments performed on four public face databases show that the proposed approach can give better generalization performance than the classic Average Neighborhood Margin Maximization (ANMM). Moreover, thanks to the use of robust margins, the proposed method down-grades gracefully when label outliers contaminate the training data set. In particular, we show that the concept of Median hit was crucial in order to get robust performance in the presence of outliers.

  20. Object-based Dimensionality Reduction in Land Surface Phenology Classification

    Directory of Open Access Journals (Sweden)

    Brian E. Bunker

    2016-11-01

    Full Text Available Unsupervised classification or clustering of multi-decadal land surface phenology provides a spatio-temporal synopsis of natural and agricultural vegetation response to environmental variability and anthropogenic activities. Notwithstanding the detailed temporal information available in calibrated bi-monthly normalized difference vegetation index (NDVI and comparable time series, typical pre-classification workflows average a pixel’s bi-monthly index within the larger multi-decadal time series. While this process is one practical way to reduce the dimensionality of time series with many hundreds of image epochs, it effectively dampens temporal variation from both intra and inter-annual observations related to land surface phenology. Through a novel application of object-based segmentation aimed at spatial (not temporal dimensionality reduction, all 294 image epochs from a Moderate Resolution Imaging Spectroradiometer (MODIS bi-monthly NDVI time series covering the northern Fertile Crescent were retained (in homogenous landscape units as unsupervised classification inputs. Given the inherent challenges of in situ or manual image interpretation of land surface phenology classes, a cluster validation approach based on transformed divergence enabled comparison between traditional and novel techniques. Improved intra-annual contrast was clearly manifest in rain-fed agriculture and inter-annual trajectories showed increased cluster cohesion, reducing the overall number of classes identified in the Fertile Crescent study area from 24 to 10. Given careful segmentation parameters, this spatial dimensionality reduction technique augments the value of unsupervised learning to generate homogeneous land surface phenology units. By combining recent scalable computational approaches to image segmentation, future work can pursue new global land surface phenology products based on the high temporal resolution signatures of vegetation index time series.

  1. Quantifying credit portfolio losses under multi-factor models

    NARCIS (Netherlands)

    G. Colldeforns-Papiol (Gemma); L. Ortiz Gracia (Luis); C.W. Oosterlee (Kees)

    2018-01-01

    textabstractIn this work, we investigate the challenging problem of estimating credit risk measures of portfolios with exposure concentration under the multi-factor Gaussian and multi-factor t-copula models. It is well-known that Monte Carlo (MC) methods are highly demanding from the computational

  2. Gaussian processes with built-in dimensionality reduction: Applications to high-dimensional uncertainty propagation

    International Nuclear Information System (INIS)

    Tripathy, Rohit; Bilionis, Ilias; Gonzalez, Marcial

    2016-01-01

    Uncertainty quantification (UQ) tasks, such as model calibration, uncertainty propagation, and optimization under uncertainty, typically require several thousand evaluations of the underlying computer codes. To cope with the cost of simulations, one replaces the real response surface with a cheap surrogate based, e.g., on polynomial chaos expansions, neural networks, support vector machines, or Gaussian processes (GP). However, the number of simulations required to learn a generic multivariate response grows exponentially as the input dimension increases. This curse of dimensionality can only be addressed, if the response exhibits some special structure that can be discovered and exploited. A wide range of physical responses exhibit a special structure known as an active subspace (AS). An AS is a linear manifold of the stochastic space characterized by maximal response variation. The idea is that one should first identify this low dimensional manifold, project the high-dimensional input onto it, and then link the projection to the output. If the dimensionality of the AS is low enough, then learning the link function is a much easier problem than the original problem of learning a high-dimensional function. The classic approach to discovering the AS requires gradient information, a fact that severely limits its applicability. Furthermore, and partly because of its reliance to gradients, it is not able to handle noisy observations. The latter is an essential trait if one wants to be able to propagate uncertainty through stochastic simulators, e.g., through molecular dynamics codes. In this work, we develop a probabilistic version of AS which is gradient-free and robust to observational noise. Our approach relies on a novel Gaussian process regression with built-in dimensionality reduction. In particular, the AS is represented as an orthogonal projection matrix that serves as yet another covariance function hyper-parameter to be estimated from the data. To train the

  3. Gaussian processes with built-in dimensionality reduction: Applications to high-dimensional uncertainty propagation

    Science.gov (United States)

    Tripathy, Rohit; Bilionis, Ilias; Gonzalez, Marcial

    2016-09-01

    Uncertainty quantification (UQ) tasks, such as model calibration, uncertainty propagation, and optimization under uncertainty, typically require several thousand evaluations of the underlying computer codes. To cope with the cost of simulations, one replaces the real response surface with a cheap surrogate based, e.g., on polynomial chaos expansions, neural networks, support vector machines, or Gaussian processes (GP). However, the number of simulations required to learn a generic multivariate response grows exponentially as the input dimension increases. This curse of dimensionality can only be addressed, if the response exhibits some special structure that can be discovered and exploited. A wide range of physical responses exhibit a special structure known as an active subspace (AS). An AS is a linear manifold of the stochastic space characterized by maximal response variation. The idea is that one should first identify this low dimensional manifold, project the high-dimensional input onto it, and then link the projection to the output. If the dimensionality of the AS is low enough, then learning the link function is a much easier problem than the original problem of learning a high-dimensional function. The classic approach to discovering the AS requires gradient information, a fact that severely limits its applicability. Furthermore, and partly because of its reliance to gradients, it is not able to handle noisy observations. The latter is an essential trait if one wants to be able to propagate uncertainty through stochastic simulators, e.g., through molecular dynamics codes. In this work, we develop a probabilistic version of AS which is gradient-free and robust to observational noise. Our approach relies on a novel Gaussian process regression with built-in dimensionality reduction. In particular, the AS is represented as an orthogonal projection matrix that serves as yet another covariance function hyper-parameter to be estimated from the data. To train the

  4. Gaussian processes with built-in dimensionality reduction: Applications to high-dimensional uncertainty propagation

    Energy Technology Data Exchange (ETDEWEB)

    Tripathy, Rohit, E-mail: rtripath@purdue.edu; Bilionis, Ilias, E-mail: ibilion@purdue.edu; Gonzalez, Marcial, E-mail: marcial-gonzalez@purdue.edu

    2016-09-15

    Uncertainty quantification (UQ) tasks, such as model calibration, uncertainty propagation, and optimization under uncertainty, typically require several thousand evaluations of the underlying computer codes. To cope with the cost of simulations, one replaces the real response surface with a cheap surrogate based, e.g., on polynomial chaos expansions, neural networks, support vector machines, or Gaussian processes (GP). However, the number of simulations required to learn a generic multivariate response grows exponentially as the input dimension increases. This curse of dimensionality can only be addressed, if the response exhibits some special structure that can be discovered and exploited. A wide range of physical responses exhibit a special structure known as an active subspace (AS). An AS is a linear manifold of the stochastic space characterized by maximal response variation. The idea is that one should first identify this low dimensional manifold, project the high-dimensional input onto it, and then link the projection to the output. If the dimensionality of the AS is low enough, then learning the link function is a much easier problem than the original problem of learning a high-dimensional function. The classic approach to discovering the AS requires gradient information, a fact that severely limits its applicability. Furthermore, and partly because of its reliance to gradients, it is not able to handle noisy observations. The latter is an essential trait if one wants to be able to propagate uncertainty through stochastic simulators, e.g., through molecular dynamics codes. In this work, we develop a probabilistic version of AS which is gradient-free and robust to observational noise. Our approach relies on a novel Gaussian process regression with built-in dimensionality reduction. In particular, the AS is represented as an orthogonal projection matrix that serves as yet another covariance function hyper-parameter to be estimated from the data. To train the

  5. Dimensional reduction in field theory and hidden symmetries in extended supergravity

    International Nuclear Information System (INIS)

    Kremmer, E.

    1985-01-01

    Dimensional reduction in field theories is discussed both in theories which do not include gravity and in gravity theories. In particular, 11-dimensional supergravity and its reduction to 4 dimensions is considered. Hidden symmetries of supergravity with N=8 in 4 dimensions, global E 7 and local SU(8)-invariances in particular are detected. The hidden symmmetries permit to interpret geometrically the scalar fields

  6. Water-Induced Dimensionality Reduction in Metal-Halide Perovskites

    KAUST Repository

    Turedi, Bekir; Lee, Kwangjae; Dursun, Ibrahim; Alamer, Badriah Jaber; Wu, Zhennan; Alarousu, Erkki; Mohammed, Omar F.; Cho, Namchul; Bakr, Osman

    2018-01-01

    . Here we employ water to directly transform films of the three-dimensional (3D) perovskite CsPbBr3 to stable two-dimensional (2D) perovskite-related CsPb2Br5. A sequential dissolution-recrystallization process governs this water induced transformation

  7. Perturbative QCD Lagrangian at large distances and stochastic dimensionality reduction. Pt. 2

    International Nuclear Information System (INIS)

    Shintani, M.

    1986-11-01

    Using the method of stochastic dimensional reduction, we derive a four-dimensional quantum effective Lagrangian for the classical Yang-Mills system coupled to the Gaussian white noise. It is found that the Lagrangian coincides with the perturbative QCD at large distances constructed in our previous paper. That formalism is based on the local covariant operator formalism which maintains the unitarity of the S-matrix. Furthermore, we show the non-perturbative equivalence between super-Lorentz invariant sectors of the effective Lagrangian and two dimensional QCD coupled to the adjoint pseudo-scalars. This implies that stochastic dimensionality reduction by two is approximately operative in QCD at large distances. (orig.)

  8. Multi-Factor Authentication: A Survey

    Directory of Open Access Journals (Sweden)

    Aleksandr Ometov

    2018-01-01

    Full Text Available Today, digitalization decisively penetrates all the sides of the modern society. One of the key enablers to maintain this process secure is authentication. It covers many different areas of a hyper-connected world, including online payments, communications, access right management, etc. This work sheds light on the evolution of authentication systems towards Multi-Factor Authentication (MFA starting from Single-Factor Authentication (SFA and through Two-Factor Authentication (2FA. Particularly, MFA is expected to be utilized for human-to-everything interactions by enabling fast, user-friendly, and reliable authentication when accessing a service. This paper surveys the already available and emerging sensors (factor providers that allow for authenticating a user with the system directly or by involving the cloud. The corresponding challenges from the user as well as the service provider perspective are also reviewed. The MFA system based on reversed Lagrange polynomial within Shamir’s Secret Sharing (SSS scheme is further proposed to enable more flexible authentication. This solution covers the cases of authenticating the user even if some of the factors are mismatched or absent. Our framework allows for qualifying the missing factors by authenticating the user without disclosing sensitive biometric data to the verification entity. Finally, a vision of the future trends in MFA is discussed.

  9. Water-Induced Dimensionality Reduction in Metal-Halide Perovskites

    KAUST Repository

    Turedi, Bekir

    2018-03-30

    Metal-halide perovskite materials are highly attractive materials for optoelectronic applications. However, the instability of perovskite materials caused by moisture and heat-induced degradation impairs future prospects of using these materials. Here we employ water to directly transform films of the three-dimensional (3D) perovskite CsPbBr3 to stable two-dimensional (2D) perovskite-related CsPb2Br5. A sequential dissolution-recrystallization process governs this water induced transformation under PbBr2 rich condition. We find that these post-synthesized 2D perovskite-related material films exhibit excellent stability against humidity and high photoluminescence quantum yield. We believe that our results provide a new synthetic method to generate stable 2D perovskite-related materials that could be applicable for light emitting device applications.

  10. On symmetry reduction and exact solutions of the linear one-dimensional Schroedinger equation

    International Nuclear Information System (INIS)

    Barannik, L.L.

    1996-01-01

    Symmetry reduction of the Schroedinger equation with potential is carried out on subalgebras of the Lie algebra which is the direct sum of the special Galilei algebra and one-dimensional algebra. Some new exact solutions are obtained

  11. Dimensional reduction and BRST approach to the description of a Regge trajectory

    International Nuclear Information System (INIS)

    Pashnev, A.I.; Tsulaya, M.M.

    1997-01-01

    The local free field theory for Regge trajectory is described in the framework of the BRST-quantization method. The corresponding BRST-charge is constructed with the help of the method of dimensional reduction

  12. Congruent reduction and mode conversion in 4-dimensional plasmas

    International Nuclear Information System (INIS)

    Friedland, L.; Kaufman, A.N.

    1987-04-01

    Standard eikonal theory reduces, to N=1, the order of the system of equations underlying wave propagation in inhomogeneous plasmas. The condition for this remarkable reducibility is that only one eigenvalue of the unreduced NxN dispersion matrix D(k,x) vanishes at a time. If, however, two or more eigenvalues of D become simultaneously small, the geometric optics reduction scheme becomes singular. These regions are associated with linear mode conversion, and are described by higher order systems. A new reduction scheme based on congruent transformations of D is developed, and it is shown that, in ''degenerate'' plasma regions, a partial reduction of order is possible. The method comprises a constructive step-by-step procedure, which, in the most frequent (doubly) degenerate case, yields a second order system, describing the pairwise mode conversion problems, the solution of which in general geometry has been found recently

  13. Symmetries, integrals, and three-dimensional reductions of Plebanski's second heavenly equation

    International Nuclear Information System (INIS)

    Neyzi, F.; Sheftel, M. B.; Yazici, D.

    2007-01-01

    We study symmetries and conservation laws for Plebanski's second heavenly equation written as a first-order nonlinear evolutionary system which admits a multi-Hamiltonian structure. We construct an optimal system of one-dimensional subalgebras and all inequivalent three-dimensional symmetry reductions of the original four-dimensional system. We consider these two-component evolutionary systems in three dimensions as natural candidates for integrable systems

  14. Coset Space Dimensional Reduction approach to the Standard Model

    International Nuclear Information System (INIS)

    Farakos, K.; Kapetanakis, D.; Koutsoumbas, G.; Zoupanos, G.

    1988-01-01

    We present a unified theory in ten dimensions based on the gauge group E 8 , which is dimensionally reduced to the Standard Mode SU 3c xSU 2 -LxU 1 , which breaks further spontaneously to SU 3L xU 1em . The model gives similar predictions for sin 2 θ w and proton decay as the minimal SU 5 G.U.T., while a natural choice of the coset space radii predicts light Higgs masses a la Coleman-Weinberg

  15. One-dimensional reduction of viscous jets. II. Applications

    Science.gov (United States)

    Pitrou, Cyril

    2018-04-01

    In a companion paper [Phys. Rev. E 97, 043115 (2018), 10.1103/PhysRevE.97.043115], a formalism allowing to describe viscous fibers as one-dimensional objects was developed. We apply it to the special case of a viscous fluid torus. This allows to highlight the differences with the basic viscous string model and with its viscous rod model extension. In particular, an elliptic deformation of the torus section appears because of surface tension effects, and this cannot be described by viscous string nor viscous rod models. Furthermore, we study the Rayleigh-Plateau instability for periodic deformations around the perfect torus, and we show that the instability is not sufficient to lead to the torus breakup in several droplets before it collapses to a single spherical drop. Conversely, a rotating torus is dynamically attracted toward a stationary solution, around which the instability can develop freely and split the torus in multiple droplets.

  16. One-dimensional reduction of viscous jets. I. Theory

    Science.gov (United States)

    Pitrou, Cyril

    2018-04-01

    We build a general formalism to describe thin viscous jets as one-dimensional objects with an internal structure. We present in full generality the steps needed to describe the viscous jets around their central line, and we argue that the Taylor expansion of all fields around that line is conveniently expressed in terms of symmetric trace-free tensors living in the two dimensions of the fiber sections. We recover the standard results of axisymmetric jets and we report the first and second corrections to the lowest order description, also allowing for a rotational component around the axis of symmetry. When applied to generally curved fibers, the lowest order description corresponds to a viscous string model whose sections are circular. However, when including the first corrections, we find that curved jets generically develop elliptic sections. Several subtle effects imply that the first corrections cannot be described by a rod model since it amounts to selectively discard some corrections. However, in a fast rotating frame, we find that the dominant effects induced by inertial and Coriolis forces should be correctly described by rod models. For completeness, we also recover the constitutive relations for forces and torques in rod models and exhibit a missing term in the lowest order expression of viscous torque. Given that our method is based on tensors, the complexity of all computations has been beaten down by using an appropriate tensor algebra package such as xAct, allowing us to obtain a one-dimensional description of curved viscous jets with all the first order corrections consistently included. Finally, we find a description for straight fibers with elliptic sections as a special case of these results, and recover that ellipticity is dynamically damped by surface tension. An application to toroidal viscous fibers is presented in the companion paper [Pitrou, Phys. Rev. E 97, 043116 (2018), 10.1103/PhysRevE.97.043116].

  17. Center-vortex dominance after dimensional reduction of SU(2) lattice gauge theory

    OpenAIRE

    Gattnar, J.; Langfeld, K.; Schafke, A.; Reinhardt, H.

    2000-01-01

    The high-temperature phase of SU(2) Yang-Mills theory is addressed by means of dimensional reduction with a special emphasis on the properties of center vortices. For this purpose, the vortex vacuum which arises from center projection is studied in pure 3-dimensional Yang-Mills theory as well as in the 3-dimensional adjoint Higgs model which describes the high temperature phase of the 4-dimensional SU(2) gauge theory. We find center-dominance within the numerical accuracy of 10%.

  18. Estimation and analysis of multifactor productivity in truck transportation : 1987 - 2003

    Science.gov (United States)

    2009-02-01

    The analysis has three objectives: 1) to estimate multifactor : productivity (MFP) in truck transportation during : 1987-2003; 2) to examine changes in multifactor productivity : in U.S. truck transportation, over time, and : to compare these changes...

  19. Relation between the pole and the minimally subtracted mass in dimensional regularization and dimensional reduction to three-loop order

    Energy Technology Data Exchange (ETDEWEB)

    Marquard, P.; Mihaila, L.; Steinhauser, M. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Theoretische Teilchenphysik; Piclum, J.H. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Theoretische Teilchenphysik]|[Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2007-02-15

    We compute the relation between the pole quark mass and the minimally subtracted quark mass in the framework of QCD applying dimensional reduction as a regularization scheme. Special emphasis is put on the evanescent couplings and the renormalization of the {epsilon}-scalar mass. As a by-product we obtain the three-loop on-shell renormalization constants Z{sub m}{sup OS} and Z{sub 2}{sup OS} in dimensional regularization and thus provide the first independent check of the analytical results computed several years ago. (orig.)

  20. Sharpening the weak gravity conjecture with dimensional reduction

    International Nuclear Information System (INIS)

    Heidenreich, Ben; Reece, Matthew; Rudelius, Tom

    2016-01-01

    We investigate the behavior of the Weak Gravity Conjecture (WGC) under toroidal compactification and RG flows, finding evidence that WGC bounds for single photons become weaker in the infrared. By contrast, we find that a photon satisfying the WGC will not necessarily satisfy it after toroidal compactification when black holes charged under the Kaluza-Klein photons are considered. Doing so either requires an infinite number of states of different charges to satisfy the WGC in the original theory or a restriction on allowed compactification radii. These subtleties suggest that if the Weak Gravity Conjecture is true, we must seek a stronger form of the conjecture that is robust under compactification. We propose a “Lattice Weak Gravity Conjecture” that meets this requirement: a superextremal particle should exist for every charge in the charge lattice. The perturbative heterotic string satisfies this conjecture. We also use compactification to explore the extent to which the WGC applies to axions. We argue that gravitational instanton solutions in theories of axions coupled to dilaton-like fields are analogous to extremal black holes, motivating a WGC for axions. This is further supported by a match between the instanton action and that of wrapped black branes in a higher-dimensional UV completion.

  1. Chaotic oscillator containing memcapacitor and meminductor and its dimensionality reduction analysis.

    Science.gov (United States)

    Yuan, Fang; Wang, Guangyi; Wang, Xiaowei

    2017-03-01

    In this paper, smooth curve models of meminductor and memcapacitor are designed, which are generalized from a memristor. Based on these models, a new five-dimensional chaotic oscillator that contains a meminductor and memcapacitor is proposed. By dimensionality reducing, this five-dimensional system can be transformed into a three-dimensional system. The main work of this paper is to give the comparisons between the five-dimensional system and its dimensionality reduction model. To investigate dynamics behaviors of the two systems, equilibrium points and stabilities are analyzed. And the bifurcation diagrams and Lyapunov exponent spectrums are used to explore their properties. In addition, digital signal processing technologies are used to realize this chaotic oscillator, and chaotic sequences are generated by the experimental device, which can be used in encryption applications.

  2. Scaling Properties of Dimensionality Reduction for Neural Populations and Network Models.

    Directory of Open Access Journals (Sweden)

    Ryan C Williamson

    2016-12-01

    Full Text Available Recent studies have applied dimensionality reduction methods to understand how the multi-dimensional structure of neural population activity gives rise to brain function. It is unclear, however, how the results obtained from dimensionality reduction generalize to recordings with larger numbers of neurons and trials or how these results relate to the underlying network structure. We address these questions by applying factor analysis to recordings in the visual cortex of non-human primates and to spiking network models that self-generate irregular activity through a balance of excitation and inhibition. We compared the scaling trends of two key outputs of dimensionality reduction-shared dimensionality and percent shared variance-with neuron and trial count. We found that the scaling properties of networks with non-clustered and clustered connectivity differed, and that the in vivo recordings were more consistent with the clustered network. Furthermore, recordings from tens of neurons were sufficient to identify the dominant modes of shared variability that generalize to larger portions of the network. These findings can help guide the interpretation of dimensionality reduction outputs in regimes of limited neuron and trial sampling and help relate these outputs to the underlying network structure.

  3. Coupled dimensionality reduction and classification for supervised and semi-supervised multilabel learning.

    Science.gov (United States)

    Gönen, Mehmet

    2014-03-01

    Coupled training of dimensionality reduction and classification is proposed previously to improve the prediction performance for single-label problems. Following this line of research, in this paper, we first introduce a novel Bayesian method that combines linear dimensionality reduction with linear binary classification for supervised multilabel learning and present a deterministic variational approximation algorithm to learn the proposed probabilistic model. We then extend the proposed method to find intrinsic dimensionality of the projected subspace using automatic relevance determination and to handle semi-supervised learning using a low-density assumption. We perform supervised learning experiments on four benchmark multilabel learning data sets by comparing our method with baseline linear dimensionality reduction algorithms. These experiments show that the proposed approach achieves good performance values in terms of hamming loss, average AUC, macro F 1 , and micro F 1 on held-out test data. The low-dimensional embeddings obtained by our method are also very useful for exploratory data analysis. We also show the effectiveness of our approach in finding intrinsic subspace dimensionality and semi-supervised learning tasks.

  4. Anisotropic inflation in a 5D standing wave braneworld and effective dimensional reduction

    Energy Technology Data Exchange (ETDEWEB)

    Gogberashvili, Merab, E-mail: gogber@gmail.com [Andronikashvili Institute of Physics, 6 Tamarashvili St., Tbilisi 0177, Georgia (United States); Javakhishvili State University, 3 Chavchavadze Ave., Tbilisi 0128, Georgia (United States); Herrera-Aguilar, Alfredo, E-mail: aha@fis.unam.mx [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apdo. Postal 48-3, 62251 Cuernavaca, Morelos (Mexico); Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, CP 58040, Morelia, Michoacán (Mexico); Malagón-Morejón, Dagoberto, E-mail: malagon@fis.unam.mx [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apdo. Postal 48-3, 62251 Cuernavaca, Morelos (Mexico); Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, CP 58040, Morelia, Michoacán (Mexico); Mora-Luna, Refugio Rigel, E-mail: rigel@ifm.umich.mx [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, CP 58040, Morelia, Michoacán (Mexico)

    2013-10-01

    We investigate a cosmological solution within the framework of a 5D standing wave braneworld model generated by gravity coupled to a massless scalar phantom-like field. By obtaining a full exact solution of the model we found a novel dynamical mechanism in which the anisotropic nature of the primordial metric gives rise to (i) inflation along certain spatial dimensions, and (ii) deflation and a shrinking reduction of the number of spatial dimensions along other directions. This dynamical mechanism can be relevant for dimensional reduction in string and other higher-dimensional theories in the attempt of getting a 4D isotropic expanding space–time.

  5. Anisotropic inflation in a 5D standing wave braneworld and effective dimensional reduction

    International Nuclear Information System (INIS)

    Gogberashvili, Merab; Herrera-Aguilar, Alfredo; Malagón-Morejón, Dagoberto; Mora-Luna, Refugio Rigel

    2013-01-01

    We investigate a cosmological solution within the framework of a 5D standing wave braneworld model generated by gravity coupled to a massless scalar phantom-like field. By obtaining a full exact solution of the model we found a novel dynamical mechanism in which the anisotropic nature of the primordial metric gives rise to (i) inflation along certain spatial dimensions, and (ii) deflation and a shrinking reduction of the number of spatial dimensions along other directions. This dynamical mechanism can be relevant for dimensional reduction in string and other higher-dimensional theories in the attempt of getting a 4D isotropic expanding space–time

  6. A finite-dimensional reduction method for slightly supercritical elliptic problems

    Directory of Open Access Journals (Sweden)

    Riccardo Molle

    2004-01-01

    Full Text Available We describe a finite-dimensional reduction method to find solutions for a class of slightly supercritical elliptic problems. A suitable truncation argument allows us to work in the usual Sobolev space even in the presence of supercritical nonlinearities: we modify the supercritical term in such a way to have subcritical approximating problems; for these problems, the finite-dimensional reduction can be obtained applying the methods already developed in the subcritical case; finally, we show that, if the truncation is realized at a sufficiently large level, then the solutions of the approximating problems, given by these methods, also solve the supercritical problems when the parameter is small enough.

  7. Neural networks for the dimensionality reduction of GOME measurement vector in the estimation of ozone profiles

    International Nuclear Information System (INIS)

    Del Frate, F.; Iapaolo, M.; Casadio, S.; Godin-Beekmann, S.; Petitdidier, M.

    2005-01-01

    Dimensionality reduction can be of crucial importance in the application of inversion schemes to atmospheric remote sensing data. In this study the problem of dimensionality reduction in the retrieval of ozone concentration profiles from the radiance measurements provided by the instrument Global Ozone Monitoring Experiment (GOME) on board of ESA satellite ERS-2 is considered. By means of radiative transfer modelling, neural networks and pruning algorithms, a complete procedure has been designed to extract the GOME spectral ranges most crucial for the inversion. The quality of the resulting retrieval algorithm has been evaluated by comparing its performance to that yielded by other schemes and co-located profiles obtained with lidar measurements

  8. Supersymmetry and the Parisi-Sourlas dimensional reduction: A rigorous proof

    International Nuclear Information System (INIS)

    Klein, A.; Landau, L.J.; Perez, J.F.

    1984-01-01

    Functional integrals that are formally related to the average correlation functions of a classical field theory in the presence of random external sources are given a rigorous meaning. Their dimensional reduction to the Schwinger functions of the corresponding quantum field theory in two fewer dimensions is proven. This is done by reexpressing those functional integrals as expectations of a supersymmetric field theory. The Parisi-Sourlas dimensional reduction of a supersymmetric field theory to a usual quantum field theory in two fewer dimensions is proven. (orig.)

  9. ANALYSIS OF IMPACT ON COMPOSITE STRUCTURES WITH THE METHOD OF DIMENSIONALITY REDUCTION

    Directory of Open Access Journals (Sweden)

    Valentin L. Popov

    2015-04-01

    Full Text Available In the present paper, we discuss the impact of rigid profiles on continua with non-local criteria for plastic yield. For the important case of media whose hardness is inversely proportional to the indentation radius, we suggest a rigorous treatment based on the method of dimensionality reduction (MDR and study the example of indentation by a conical profile.

  10. Some remarks on dimensional reduction of Gauge theories and model building

    International Nuclear Information System (INIS)

    Rudolph, G.; Karl-Marx-Universitaet, Leipzig; Volobujev, I.P.

    1989-01-01

    We study the group-theoretical aspect of dimensional reduction of pure gauge theories and propose a method of solving the constraint equations for scalar fields. We show that there are possibilities of model building which differ from those commonly used. In particular, we give examples in which the resulting potential is not of Higgs type. (orig.)

  11. The N=4 supersymmetric E8 gauge theory and coset space dimensional reduction

    International Nuclear Information System (INIS)

    Olive, D.; West, P.

    1983-01-01

    Reasons are given to suggest that the N=4 supersymmetric E 8 gauge theory be considered as a serious candidate for a physical theory. The symmetries of this theory are broken by a scheme based on coset space dimensional reduction. The resulting theory possesses four conventional generations of low-mass fermions together with their mirror particles. (orig.)

  12. Ultraviolet finiteness of N = 8 supergravity, spontaneously broken by dimensional reduction

    International Nuclear Information System (INIS)

    Sezgin, E.; Nieuwenhuizen, P. van

    1982-06-01

    The one-loop corrections to scalar-scalar scattering in N = 8 supergravity with 4 masses from dimensional reduction, are finite. We discuss various mechanisms that cancel the cosmological constant and infra-red divergences due to finite but non-vanishing tadpoles. (author)

  13. Dimensional reduction of 10d heterotic string effective lagrangian with higher derivative terms

    International Nuclear Information System (INIS)

    Lalak, Z.; Pawelczyk, J.

    1989-11-01

    Dimensional reduction of the 10d Supergravity-Yang-Mills theories containing up to four derivatives is described. Unexpected nondiagonal corrections to 4d gauge kinetic function and negative contributions to scalar potential are found. We analyzed the general structure of the resulting lagrangian and discuss the possible phenomenological consequences. (author)

  14. A trace ratio maximization approach to multiple kernel-based dimensionality reduction.

    Science.gov (United States)

    Jiang, Wenhao; Chung, Fu-lai

    2014-01-01

    Most dimensionality reduction techniques are based on one metric or one kernel, hence it is necessary to select an appropriate kernel for kernel-based dimensionality reduction. Multiple kernel learning for dimensionality reduction (MKL-DR) has been recently proposed to learn a kernel from a set of base kernels which are seen as different descriptions of data. As MKL-DR does not involve regularization, it might be ill-posed under some conditions and consequently its applications are hindered. This paper proposes a multiple kernel learning framework for dimensionality reduction based on regularized trace ratio, termed as MKL-TR. Our method aims at learning a transformation into a space of lower dimension and a corresponding kernel from the given base kernels among which some may not be suitable for the given data. The solutions for the proposed framework can be found based on trace ratio maximization. The experimental results demonstrate its effectiveness in benchmark datasets, which include text, image and sound datasets, for supervised, unsupervised as well as semi-supervised settings. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Dimensional reduction in Bose-Einstein-condensed alkali-metal vapors

    International Nuclear Information System (INIS)

    Salasnich, L.; Reatto, L.; Parola, A.

    2004-01-01

    We investigate the effects of dimensional reduction in atomic Bose-Einstein condensates (BECs) induced by a strong harmonic confinement in the cylindric radial direction or in the cylindric axial direction. The former case corresponds to a transition from three dimensions (3D) to 1D in cigar-shaped BECs, while the latter case corresponds to a transition from 3D to 2D in disk-shaped BECs. We analyze the first sound velocity in axially homogeneous cigar-shaped BECs and in radially homogeneous disk-shaped BECs. We consider also the dimensional reduction in a BEC confined by a harmonic potential both in the radial direction and in the axial direction. By using a variational approach, we calculate monopole and quadrupole collective oscillations of the BEC. We find that the frequencies of these collective oscillations are related to the dimensionality and to the repulsive or attractive interatomic interaction

  16. A Recurrent Probabilistic Neural Network with Dimensionality Reduction Based on Time-series Discriminant Component Analysis.

    Science.gov (United States)

    Hayashi, Hideaki; Shibanoki, Taro; Shima, Keisuke; Kurita, Yuichi; Tsuji, Toshio

    2015-12-01

    This paper proposes a probabilistic neural network (NN) developed on the basis of time-series discriminant component analysis (TSDCA) that can be used to classify high-dimensional time-series patterns. TSDCA involves the compression of high-dimensional time series into a lower dimensional space using a set of orthogonal transformations and the calculation of posterior probabilities based on a continuous-density hidden Markov model with a Gaussian mixture model expressed in the reduced-dimensional space. The analysis can be incorporated into an NN, which is named a time-series discriminant component network (TSDCN), so that parameters of dimensionality reduction and classification can be obtained simultaneously as network coefficients according to a backpropagation through time-based learning algorithm with the Lagrange multiplier method. The TSDCN is considered to enable high-accuracy classification of high-dimensional time-series patterns and to reduce the computation time taken for network training. The validity of the TSDCN is demonstrated for high-dimensional artificial data and electroencephalogram signals in the experiments conducted during the study.

  17. Using Artificial Intelligence Techniques to Implement a Multifactor Authentication System

    Directory of Open Access Journals (Sweden)

    Jackson Phiri

    2011-08-01

    Full Text Available The recent years have seen a rise in the number of cases of cyber-crime committed through identity theft and fraud. To address this problem, this paper uses adaptive neural-fuzzy inference system, fuzzy logic and artificial neural network to implement a multifactor authentication system through a technique of information fusion. To begin with, the identity attributes are mined using the three corpora from three major sources namely the social networks, a set of questionnaires and application forms from the various services offered both in the real and cyberspace. The statistical information generated by the corpora is then used to compose an identity attribute metric model. The composed identity attributes metrics values classified as biometrics, device metrics and pseudo metrics are then fused at the score level through a technique of information fusion in a multifactor authentication system by using each of the above artificial intelligence technologies and the results compared.

  18. Restoration of dimensional reduction in the random-field Ising model at five dimensions

    Science.gov (United States)

    Fytas, Nikolaos G.; Martín-Mayor, Víctor; Picco, Marco; Sourlas, Nicolas

    2017-04-01

    The random-field Ising model is one of the few disordered systems where the perturbative renormalization group can be carried out to all orders of perturbation theory. This analysis predicts dimensional reduction, i.e., that the critical properties of the random-field Ising model in D dimensions are identical to those of the pure Ising ferromagnet in D -2 dimensions. It is well known that dimensional reduction is not true in three dimensions, thus invalidating the perturbative renormalization group prediction. Here, we report high-precision numerical simulations of the 5D random-field Ising model at zero temperature. We illustrate universality by comparing different probability distributions for the random fields. We compute all the relevant critical exponents (including the critical slowing down exponent for the ground-state finding algorithm), as well as several other renormalization-group invariants. The estimated values of the critical exponents of the 5D random-field Ising model are statistically compatible to those of the pure 3D Ising ferromagnet. These results support the restoration of dimensional reduction at D =5 . We thus conclude that the failure of the perturbative renormalization group is a low-dimensional phenomenon. We close our contribution by comparing universal quantities for the random-field problem at dimensions 3 ≤D equality at all studied dimensions.

  19. Aggregate Multi-Factor Productivity: Measurement Issues in OECD Countries

    OpenAIRE

    Egert, Balazs

    2018-01-01

    This paper analyses for 34 OECD countries the extent to which the calculation of aggregate multi-factor productivity (MFP) is sensitive to alternative parameterisations. The starting point is the definition of MFP used in previous work in the OECD’s Economics Department (e.g. Johansson et al. 2013). They include alternative MFP measures, with human capital included or excluded, with different measures of Purchasing Power Parity (PPP) exchange rates, using time-varying capital depreciation rat...

  20. Behavioural Biometrics for Multi-factor Authentication in Biomedicine

    Czech Academy of Sciences Publication Activity Database

    Schlenker, Anna; Šárek, M.

    2012-01-01

    Roč. 8, č. 5 (2012), s. 19-24 ISSN 1801-5603 Grant - others:GA MŠk(CZ) LM2010005; GA UK(CZ) SVV-2012-264513 Institutional support: RVO:67985807 Keywords : biometric s * anatomical-physiological biometric s * behavioural biometric s * multi-factor authentication * keystroke dynamics * mouse dynamics Subject RIV: IN - Informatics, Computer Science http://www.ejbi.org/img/ejbi/2012/5/Schlenker_en.pdf

  1. A rough multi-factor model of electricity spot prices

    International Nuclear Information System (INIS)

    Bennedsen, Mikkel

    2017-01-01

    We introduce a new continuous-time mathematical model of electricity spot prices which accounts for the most important stylized facts of these time series: seasonality, spikes, stochastic volatility, and mean reversion. Empirical studies have found a possible fifth stylized fact, roughness, and our approach explicitly incorporates this into the model of the prices. Our setup generalizes the popular Ornstein–Uhlenbeck-based multi-factor framework of and allows us to perform statistical tests to distinguish between an Ornstein–Uhlenbeck-based model and a rough model. Further, through the multi-factor approach we account for seasonality and spikes before estimating – and making inference on – the degree of roughness. This is novel in the literature and we present simulation evidence showing that these precautions are crucial for accurate estimation. Lastly, we estimate our model on recent data from six European energy exchanges and find statistical evidence of roughness in five out of six markets. As an application of our model, we show how, in these five markets, a rough component improves short term forecasting of the prices. - Highlights: • Statistical modeling of electricity spot prices • Multi-factor decomposition • Roughness • Electricity price forecasting

  2. Target oriented dimensionality reduction of hyperspectral data by Kernel Fukunaga-Koontz Transform

    Science.gov (United States)

    Binol, Hamidullah; Ochilov, Shuhrat; Alam, Mohammad S.; Bal, Abdullah

    2017-02-01

    Principal component analysis (PCA) is a popular technique in remote sensing for dimensionality reduction. While PCA is suitable for data compression, it is not necessarily an optimal technique for feature extraction, particularly when the features are exploited in supervised learning applications (Cheriyadat and Bruce, 2003) [1]. Preserving features belonging to the target is very crucial to the performance of target detection/recognition techniques. Fukunaga-Koontz Transform (FKT) based supervised band reduction technique can be used to provide this requirement. FKT achieves feature selection by transforming into a new space in where feature classes have complimentary eigenvectors. Analysis of these eigenvectors under two classes, target and background clutter, can be utilized for target oriented band reduction since each basis functions best represent target class while carrying least information of the background class. By selecting few eigenvectors which are the most relevant to the target class, dimension of hyperspectral data can be reduced and thus, it presents significant advantages for near real time target detection applications. The nonlinear properties of the data can be extracted by kernel approach which provides better target features. Thus, we propose constructing kernel FKT (KFKT) to present target oriented band reduction. The performance of the proposed KFKT based target oriented dimensionality reduction algorithm has been tested employing two real-world hyperspectral data and results have been reported consequently.

  3. Reduction formalism for dimensionally regulated one-loop N-point integrals

    International Nuclear Information System (INIS)

    Binoth, T.; Guillet, J.Ph.; Heinrich, G.

    2000-01-01

    We consider one-loop scalar and tensor integrals with an arbitrary number of external legs relevant for multi-parton processes in massless theories. We present a procedure to reduce N-point scalar functions with generic 4-dimensional external momenta to box integrals in (4-2ε) dimensions. We derive a formula valid for arbitrary N and give an explicit expression for N=6. Further a tensor reduction method for N-point tensor integrals is presented. We prove that generically higher dimensional integrals contribute only to order ε for N≥5. The tensor reduction can be solved iteratively such that any tensor integral is expressible in terms of scalar integrals. Explicit formulas are given up to N=6

  4. Dimensionality Reduction Methods: Comparative Analysis of methods PCA, PPCA and KPCA

    Directory of Open Access Journals (Sweden)

    Jorge Arroyo-Hernández

    2016-01-01

    Full Text Available The dimensionality reduction methods are algorithms mapping the set of data in subspaces derived from the original space, of fewer dimensions, that allow a description of the data at a lower cost. Due to their importance, they are widely used in processes associated with learning machine. This article presents a comparative analysis of PCA, PPCA and KPCA dimensionality reduction methods. A reconstruction experiment of worm-shape data was performed through structures of landmarks located in the body contour, with methods having different number of main components. The results showed that all methods can be seen as alternative processes. Nevertheless, thanks to the potential for analysis in the features space and the method for calculation of its preimage presented, KPCA offers a better method for recognition process and pattern extraction

  5. Dimensionality Reduction of Hyperspectral Image with Graph-Based Discriminant Analysis Considering Spectral Similarity

    Directory of Open Access Journals (Sweden)

    Fubiao Feng

    2017-03-01

    Full Text Available Recently, graph embedding has drawn great attention for dimensionality reduction in hyperspectral imagery. For example, locality preserving projection (LPP utilizes typical Euclidean distance in a heat kernel to create an affinity matrix and projects the high-dimensional data into a lower-dimensional space. However, the Euclidean distance is not sufficiently correlated with intrinsic spectral variation of a material, which may result in inappropriate graph representation. In this work, a graph-based discriminant analysis with spectral similarity (denoted as GDA-SS measurement is proposed, which fully considers curves changing description among spectral bands. Experimental results based on real hyperspectral images demonstrate that the proposed method is superior to traditional methods, such as supervised LPP, and the state-of-the-art sparse graph-based discriminant analysis (SGDA.

  6. N=2-Maxwell-Chern-Simons model with anomalous magnetic moment coupling via dimensional reduction

    International Nuclear Information System (INIS)

    Christiansen, H.R.; Cunha, M.S.; Helayel Neto, Jose A.; Manssur, L.R.U; Nogueira, A.L.M.A.

    1998-02-01

    An N=1-supersymmetric version of the Cremmer-Scherk-Kalb-Ramond model with non-minimal coupling to matter is built up both in terms of superfields and in a component field formalism. By adopting a dimensional reduction procedure, the N=2-D=3 counterpart of the model comes out, with two main features: a genuine (diagonal) Chern-Simons term and an anomalous magnetic moment coupling between matter and the gauge potential. (author)

  7. Use of dimensionality reduction for structural mapping of hip joint osteoarthritis data

    International Nuclear Information System (INIS)

    Theoharatos, C; Fotopoulos, S; Boniatis, I; Panayiotakis, G; Panagiotopoulos, E

    2009-01-01

    A visualization-based, computer-oriented, classification scheme is proposed for assessing the severity of hip osteoarthritis (OA) using dimensionality reduction techniques. The introduced methodology tries to cope with the confined ability of physicians to structurally organize the entire available set of medical data into semantically similar categories and provide the capability to make visual observations among the ensemble of data using low-dimensional biplots. In this work, 18 pelvic radiographs of patients with verified unilateral hip OA are evaluated by experienced physicians and assessed into Normal, Mild and Severe following the Kellgren and Lawrence scale. Two regions of interest corresponding to radiographic hip joint spaces are determined and representative features are extracted using a typical texture analysis technique. The structural organization of all hip OA data is accomplished using distance and topology preservation-based dimensionality reduction techniques. The resulting map is a low-dimensional biplot that reflects the intrinsic organization of the ensemble of available data and which can be directly accessed by the physician. The conceivable visualization scheme can potentially reveal critical data similarities and help the operator to visually estimate their initial diagnosis. In addition, it can be used to detect putative clustering tendencies, examine the presence of data similarities and indicate the existence of possible false alarms in the initial perceptual evaluation

  8. Participatory three dimensional mapping for the preparation of landslide disaster risk reduction program

    Science.gov (United States)

    Kusratmoko, Eko; Wibowo, Adi; Cholid, Sofyan; Pin, Tjiong Giok

    2017-07-01

    This paper presents the results of applications of participatory three dimensional mapping (P3DM) method for fqcilitating the people of Cibanteng' village to compile a landslide disaster risk reduction program. Physical factors, as high rainfall, topography, geology and land use, and coupled with the condition of demographic and social-economic factors, make up the Cibanteng region highly susceptible to landslides. During the years 2013-2014 has happened 2 times landslides which caused economic losses, as a result of damage to homes and farmland. Participatory mapping is one part of the activities of community-based disaster risk reduction (CBDRR)), because of the involvement of local communities is a prerequisite for sustainable disaster risk reduction. In this activity, participatory mapping method are done in two ways, namely participatory two-dimensional mapping (P2DM) with a focus on mapping of disaster areas and participatory three-dimensional mapping (P3DM) with a focus on the entire territory of the village. Based on the results P3DM, the ability of the communities in understanding the village environment spatially well-tested and honed, so as to facilitate the preparation of the CBDRR programs. Furthermore, the P3DM method can be applied to another disaster areas, due to it becomes a medium of effective dialogue between all levels of involved communities.

  9. Three-dimensional assessment of unilateral subcondylar fracture using computed tomography after open reduction

    Directory of Open Access Journals (Sweden)

    Sathya Kumar Devireddy

    2014-01-01

    Full Text Available Objective: The aim was to assess the accuracy of three-dimensional anatomical reductions achieved by open method of treatment in cases of displaced unilateral mandibular subcondylar fractures using preoperative (pre op and postoperative (post op computed tomography (CT scans. Materials and Methods: In this prospective study, 10 patients with unilateral sub condylar fractures confirmed by an orthopantomogram were included. A pre op and post op CT after 1 week of surgical procedure was taken in axial, coronal and sagittal plane along with three-dimensional reconstruction. Standard anatomical parameters, which undergo changes due to fractures of the mandibular condyle were measured in pre and post op CT scans in three planes and statistically analysed for the accuracy of the reduction comparing the following variables: (a Pre op fractured and nonfractured side (b post op fractured and nonfractured side (c pre op fractured and post op fractured side. P < 0.05 was considered as significant. Results: Three-dimensional anatomical reduction was possible in 9 out of 10 cases (90%. The statistical analysis of each parameter in three variables revealed (P < 0.05 that there was a gross change in the dimensions of the parameters obtained in pre op fractured and nonfractured side. When these parameters were assessed in post op CT for the three variables there was no statistical difference between the post op fractured side and non fractured side. The same parameters were analysed for the three variables in pre op fractured and post op fractured side and found significant statistical difference suggesting a considerable change in the dimensions of the fractured side post operatively. Conclusion: The statistical and clinical results in our study emphasised that it is possible to fix the condyle in three-dimensional anatomical positions with open method of treatment and avoid post op degenerative joint changes. CT is the ideal imaging tool and should be used on

  10. The equivalence of information-theoretic and likelihood-based methods for neural dimensionality reduction.

    Directory of Open Access Journals (Sweden)

    Ross S Williamson

    2015-04-01

    Full Text Available Stimulus dimensionality-reduction methods in neuroscience seek to identify a low-dimensional space of stimulus features that affect a neuron's probability of spiking. One popular method, known as maximally informative dimensions (MID, uses an information-theoretic quantity known as "single-spike information" to identify this space. Here we examine MID from a model-based perspective. We show that MID is a maximum-likelihood estimator for the parameters of a linear-nonlinear-Poisson (LNP model, and that the empirical single-spike information corresponds to the normalized log-likelihood under a Poisson model. This equivalence implies that MID does not necessarily find maximally informative stimulus dimensions when spiking is not well described as Poisson. We provide several examples to illustrate this shortcoming, and derive a lower bound on the information lost when spiking is Bernoulli in discrete time bins. To overcome this limitation, we introduce model-based dimensionality reduction methods for neurons with non-Poisson firing statistics, and show that they can be framed equivalently in likelihood-based or information-theoretic terms. Finally, we show how to overcome practical limitations on the number of stimulus dimensions that MID can estimate by constraining the form of the non-parametric nonlinearity in an LNP model. We illustrate these methods with simulations and data from primate visual cortex.

  11. Multifactor-Driven Hierarchical Routing on Enterprise Service Bus

    Science.gov (United States)

    Mi, Xueqiang; Tang, Xinhuai; Yuan, Xiaozhou; Chen, Delai; Luo, Xiangfeng

    Message Routing is the foremost functionality on Enterprise Service Bus (ESB), but current ESB products don't provide an expected solution for it, especially in the aspects of runtime route change mechanism and service orchestration model. In order to solve the above drawbacks, this paper proposes a multifactor-driven hierarchical routing (MDHR) model. MDHR defines three layers for message routing on ESB. Message layer gives the original support for message delivery. Application layer can integration or encapsulate some legacy applications or un-standard services. Business layer introduces business model to supplies developers with a business rule configuration, which supports enterprise integration patterns and simplifies the service orchestration on ESB.

  12. Computational genetic neuroanatomy of the developing mouse brain: dimensionality reduction, visualization, and clustering

    Science.gov (United States)

    2013-01-01

    Background The structured organization of cells in the brain plays a key role in its functional efficiency. This delicate organization is the consequence of unique molecular identity of each cell gradually established by precise spatiotemporal gene expression control during development. Currently, studies on the molecular-structural association are beginning to reveal how the spatiotemporal gene expression patterns are related to cellular differentiation and structural development. Results In this article, we aim at a global, data-driven study of the relationship between gene expressions and neuroanatomy in the developing mouse brain. To enable visual explorations of the high-dimensional data, we map the in situ hybridization gene expression data to a two-dimensional space by preserving both the global and the local structures. Our results show that the developing brain anatomy is largely preserved in the reduced gene expression space. To provide a quantitative analysis, we cluster the reduced data into groups and measure the consistency with neuroanatomy at multiple levels. Our results show that the clusters in the low-dimensional space are more consistent with neuroanatomy than those in the original space. Conclusions Gene expression patterns and developing brain anatomy are closely related. Dimensionality reduction and visual exploration facilitate the study of this relationship. PMID:23845024

  13. Lifetime of rho meson in correlation with magnetic-dimensional reduction

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, Mamiya [Nagoya University, Department of Physics, Nagoya (Japan); Matsuzaki, Shinya [Nagoya University, Department of Physics, Nagoya (Japan); Nagoya University, Institute for Advanced Research, Nagoya (Japan)

    2017-04-15

    It is naively expected that in a strong magnetic configuration, the Landau quantization ceases the neutral rho meson to decay to the charged pion pair, so the neutral rho meson will be long-lived. To closely access this naive observation, we explicitly compute the charged pion loop in the magnetic field at the one-loop level, to evaluate the magnetic dependence of the lifetime for the neutral rho meson as well as its mass. Due to the dimensional reduction induced by the magnetic field (violation of the Lorentz invariance), the polarization (spin s{sub z} = 0, ±1) modes of the rho meson, as well as the corresponding pole mass and width, are decomposed in a nontrivial manner compared to the vacuum case. To see the significance of the reduction effect, we simply take the lowest Landau level approximation to analyze the spin-dependent rho masses and widths. We find that the ''fate'' of the rho meson may be more complicated because of the magnetic-dimensional reduction: as the magnetic field increases, the rho width for the spin s{sub z} = 0 starts to develop, reaches a peak, then vanishes at the critical magnetic field to which the folklore refers. On the other side, the decay rates of the other rhos for s{sub z} = ±1 monotonically increase as the magnetic field develops. The correlation between the polarization dependence and the Landau level truncation is also addressed. (orig.)

  14. Puzzle Imaging: Using Large-Scale Dimensionality Reduction Algorithms for Localization.

    Science.gov (United States)

    Glaser, Joshua I; Zamft, Bradley M; Church, George M; Kording, Konrad P

    2015-01-01

    Current high-resolution imaging techniques require an intact sample that preserves spatial relationships. We here present a novel approach, "puzzle imaging," that allows imaging a spatially scrambled sample. This technique takes many spatially disordered samples, and then pieces them back together using local properties embedded within the sample. We show that puzzle imaging can efficiently produce high-resolution images using dimensionality reduction algorithms. We demonstrate the theoretical capabilities of puzzle imaging in three biological scenarios, showing that (1) relatively precise 3-dimensional brain imaging is possible; (2) the physical structure of a neural network can often be recovered based only on the neural connectivity matrix; and (3) a chemical map could be reproduced using bacteria with chemosensitive DNA and conjugative transfer. The ability to reconstruct scrambled images promises to enable imaging based on DNA sequencing of homogenized tissue samples.

  15. A Multifactor Secure Authentication System for Wireless Payment

    Science.gov (United States)

    Sanyal, Sugata; Tiwari, Ayu; Sanyal, Sudip

    Organizations are deploying wireless based online payment applications to expand their business globally, it increases the growing need of regulatory requirements for the protection of confidential data, and especially in internet based financial areas. Existing internet based authentication systems often use either the Web or the Mobile channel individually to confirm the claimed identity of the remote user. The vulnerability is that access is based on only single factor authentication which is not secure to protect user data, there is a need of multifactor authentication. This paper proposes a new protocol based on multifactor authentication system that is both secure and highly usable. It uses a novel approach based on Transaction Identification Code and SMS to enforce another security level with the traditional Login/password system. The system provides a highly secure environment that is simple to use and deploy with in a limited resources that does not require any change in infrastructure or underline protocol of wireless network. This Protocol for Wireless Payment is extended as a two way authentications system to satisfy the emerging market need of mutual authentication and also supports secure B2B communication which increases faith of the user and business organizations on wireless financial transaction using mobile devices.

  16. The (2+1)-dimensional axial universes—solutions to the Einstein equations, dimensional reduction points and Klein–Fock–Gordon waves

    International Nuclear Information System (INIS)

    Fiziev, P P; Shirkov, D V

    2012-01-01

    The paper presents a generalization and further development of our recent publications, where solutions of the Klein–Fock–Gordon equation defined on a few particular D = (2 + 1)-dimensional static spacetime manifolds were considered. The latter involve toy models of two-dimensional spaces with axial symmetry, including dimensional reduction to the one-dimensional space as a singular limiting case. Here, the non-static models of space geometry with axial symmetry are under consideration. To make these models closer to physical reality, we define a set of ‘admissible’ shape functions ρ(t, z) as the (2 + 1)-dimensional Einstein equation solutions in the vacuum spacetime, in the presence of the Λ-term and for the spacetime filled with the standard ‘dust’. It is curious that in the last case the Einstein equations reduce to the well-known Monge–Ampère equation, thus enabling one to obtain the general solution of the Cauchy problem, as well as a set of other specific solutions involving one arbitrary function. A few explicit solutions of the Klein–Fock–Gordon equation in this set are given. An interesting qualitative feature of these solutions relates to the dimensional reduction points, their classification and time behavior. In particular, these new entities could provide us with novel insight into the nature of P- and T-violations and of the Big Bang. A short comparison with other attempts to utilize the dimensional reduction of the spacetime is given. (paper)

  17. Wideband radar cross section reduction using two-dimensional phase gradient metasurfaces

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yongfeng; Qu, Shaobo; Wang, Jiafu; Chen, Hongya [College of Science, Air Force Engineering University, Xi' an, Shaanxi 710051 (China); Zhang, Jieqiu [College of Science, Air Force Engineering University, Xi' an, Shaanxi 710051 (China); Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Xu, Zhuo [Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Zhang, Anxue [School of Electronics and Information Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China)

    2014-06-02

    Phase gradient metasurface (PGMs) are artificial surfaces that can provide pre-defined in-plane wave-vectors to manipulate the directions of refracted/reflected waves. In this Letter, we propose to achieve wideband radar cross section (RCS) reduction using two-dimensional (2D) PGMs. A 2D PGM was designed using a square combination of 49 split-ring sub-unit cells. The PGM can provide additional wave-vectors along the two in-plane directions simultaneously, leading to either surface wave conversion, deflected reflection, or diffuse reflection. Both the simulation and experiment results verified the wide-band, polarization-independent, high-efficiency RCS reduction induced by the 2D PGM.

  18. Wideband radar cross section reduction using two-dimensional phase gradient metasurfaces

    International Nuclear Information System (INIS)

    Li, Yongfeng; Qu, Shaobo; Wang, Jiafu; Chen, Hongya; Zhang, Jieqiu; Xu, Zhuo; Zhang, Anxue

    2014-01-01

    Phase gradient metasurface (PGMs) are artificial surfaces that can provide pre-defined in-plane wave-vectors to manipulate the directions of refracted/reflected waves. In this Letter, we propose to achieve wideband radar cross section (RCS) reduction using two-dimensional (2D) PGMs. A 2D PGM was designed using a square combination of 49 split-ring sub-unit cells. The PGM can provide additional wave-vectors along the two in-plane directions simultaneously, leading to either surface wave conversion, deflected reflection, or diffuse reflection. Both the simulation and experiment results verified the wide-band, polarization-independent, high-efficiency RCS reduction induced by the 2D PGM.

  19. Comparison of dimensionality reduction techniques for the fault diagnosis of mono block centrifugal pump using vibration signals

    Directory of Open Access Journals (Sweden)

    N.R. Sakthivel

    2014-03-01

    Full Text Available Bearing fault, Impeller fault, seal fault and cavitation are the main causes of breakdown in a mono block centrifugal pump and hence, the detection and diagnosis of these mechanical faults in a mono block centrifugal pump is very crucial for its reliable operation. Based on a continuous acquisition of signals with a data acquisition system, it is possible to classify the faults. This is achieved by the extraction of features from the measured data and employing data mining approaches to explore the structural information hidden in the signals acquired. In the present study, statistical features derived from the vibration data are used as the features. In order to increase the robustness of the classifier and to reduce the data processing load, dimensionality reduction is necessary. In this paper dimensionality reduction is performed using traditional dimensionality reduction techniques and nonlinear dimensionality reduction techniques. The effectiveness of each dimensionality reduction technique is also verified using visual analysis. The reduced feature set is then classified using a decision tree. The results obtained are compared with those generated by classifiers such as Naïve Bayes, Bayes Net and kNN. The effort is to bring out the better dimensionality reduction technique–classifier combination.

  20. Rhythmic dynamics and synchronization via dimensionality reduction: application to human gait.

    Directory of Open Access Journals (Sweden)

    Jie Zhang

    Full Text Available Reliable characterization of locomotor dynamics of human walking is vital to understanding the neuromuscular control of human locomotion and disease diagnosis. However, the inherent oscillation and ubiquity of noise in such non-strictly periodic signals pose great challenges to current methodologies. To this end, we exploit the state-of-the-art technology in pattern recognition and, specifically, dimensionality reduction techniques, and propose to reconstruct and characterize the dynamics accurately on the cycle scale of the signal. This is achieved by deriving a low-dimensional representation of the cycles through global optimization, which effectively preserves the topology of the cycles that are embedded in a high-dimensional Euclidian space. Our approach demonstrates a clear advantage in capturing the intrinsic dynamics and probing the subtle synchronization patterns from uni/bivariate oscillatory signals over traditional methods. Application to human gait data for healthy subjects and diabetics reveals a significant difference in the dynamics of ankle movements and ankle-knee coordination, but not in knee movements. These results indicate that the impaired sensory feedback from the feet due to diabetes does not influence the knee movement in general, and that normal human walking is not critically dependent on the feedback from the peripheral nervous system.

  1. Dimensionality Reduction for Hyperspectral Data Based on Class-Aware Tensor Neighborhood Graph and Patch Alignment.

    Science.gov (United States)

    Gao, Yang; Wang, Xuesong; Cheng, Yuhu; Wang, Z Jane

    2015-08-01

    To take full advantage of hyperspectral information, to avoid data redundancy and to address the curse of dimensionality concern, dimensionality reduction (DR) becomes particularly important to analyze hyperspectral data. Exploring the tensor characteristic of hyperspectral data, a DR algorithm based on class-aware tensor neighborhood graph and patch alignment is proposed here. First, hyperspectral data are represented in the tensor form through a window field to keep the spatial information of each pixel. Second, using a tensor distance criterion, a class-aware tensor neighborhood graph containing discriminating information is obtained. In the third step, employing the patch alignment framework extended to the tensor space, we can obtain global optimal spectral-spatial information. Finally, the solution of the tensor subspace is calculated using an iterative method and low-dimensional projection matrixes for hyperspectral data are obtained accordingly. The proposed method effectively explores the spectral and spatial information in hyperspectral data simultaneously. Experimental results on 3 real hyperspectral datasets show that, compared with some popular vector- and tensor-based DR algorithms, the proposed method can yield better performance with less tensor training samples required.

  2. Lie symmetry analysis and reduction for exact solution of (2+1)-dimensional Bogoyavlensky-Konopelchenko equation by geometric approach

    Science.gov (United States)

    Ray, S. Saha

    2018-04-01

    In this paper, the symmetry analysis and similarity reduction of the (2+1)-dimensional Bogoyavlensky-Konopelchenko (B-K) equation are investigated by means of the geometric approach of an invariance group, which is equivalent to the classical Lie symmetry method. Using the extended Harrison and Estabrook’s differential forms approach, the infinitesimal generators for (2+1)-dimensional B-K equation are obtained. Firstly, the vector field associated with the Lie group of transformation is derived. Then the symmetry reduction and the corresponding explicit exact solution of (2+1)-dimensional B-K equation is obtained.

  3. Probabilistic Multi-Factor Interaction Model for Complex Material Behavior

    Science.gov (United States)

    Abumeri, Galib H.; Chamis, Christos C.

    2010-01-01

    Complex material behavior is represented by a single equation of product form to account for interaction among the various factors. The factors are selected by the physics of the problem and the environment that the model is to represent. For example, different factors will be required for each to represent temperature, moisture, erosion, corrosion, etc. It is important that the equation represent the physics of the behavior in its entirety accurately. The Multi-Factor Interaction Model (MFIM) is used to evaluate the divot weight (foam weight ejected) from the external launch tanks. The multi-factor has sufficient degrees of freedom to evaluate a large number of factors that may contribute to the divot ejection. It also accommodates all interactions by its product form. Each factor has an exponent that satisfies only two points - the initial and final points. The exponent describes a monotonic path from the initial condition to the final. The exponent values are selected so that the described path makes sense in the absence of experimental data. In the present investigation, the data used were obtained by testing simulated specimens in launching conditions. Results show that the MFIM is an effective method of describing the divot weight ejected under the conditions investigated. The problem lies in how to represent the divot weight with a single equation. A unique solution to this problem is a multi-factor equation of product form. Each factor is of the following form (1 xi/xf)ei, where xi is the initial value, usually at ambient conditions, xf the final value, and ei the exponent that makes the curve represented unimodal that meets the initial and final values. The exponents are either evaluated by test data or by technical judgment. A minor disadvantage may be the selection of exponents in the absence of any empirical data. This form has been used successfully in describing the foam ejected in simulated space environmental conditions. Seven factors were required

  4. Optimal dimensionality reduction of complex dynamics: the chess game as diffusion on a free-energy landscape.

    Science.gov (United States)

    Krivov, Sergei V

    2011-07-01

    Dimensionality reduction is ubiquitous in the analysis of complex dynamics. The conventional dimensionality reduction techniques, however, focus on reproducing the underlying configuration space, rather than the dynamics itself. The constructed low-dimensional space does not provide a complete and accurate description of the dynamics. Here I describe how to perform dimensionality reduction while preserving the essential properties of the dynamics. The approach is illustrated by analyzing the chess game--the archetype of complex dynamics. A variable that provides complete and accurate description of chess dynamics is constructed. The winning probability is predicted by describing the game as a random walk on the free-energy landscape associated with the variable. The approach suggests a possible way of obtaining a simple yet accurate description of many important complex phenomena. The analysis of the chess game shows that the approach can quantitatively describe the dynamics of processes where human decision-making plays a central role, e.g., financial and social dynamics.

  5. The supersymmetric Adler-Bardeen theorem and regularization by dimensional reduction

    International Nuclear Information System (INIS)

    Ensign, P.; Mahanthappa, K.T.

    1987-01-01

    We examine the subtraction scheme dependence of the anomaly of the supersymmetric, gauge singlet axial current in pure and coupled supersymmetric Yang-Mills theories. Preserving supersymmetry and gauge invariance explicitly by using supersymmetric background field theory and dimensional reduction, we show that only the one-loop value of the axial anomaly is subtraction scheme independent, and that one can always define a subtraction scheme in which the Adler-Bardeen theorem is satisfied to all orders in perturbation theory. In general this subtraction scheme may be non-minimal, but in both the pure and the coupled theories, the Adler-Bardeen theorem is satisfied to two loops in minimal subtraction. (orig.)

  6. Fractional exclusion and braid statistics in one dimension: a study via dimensional reduction of Chern-Simons theory

    Science.gov (United States)

    Ye, Fei; Marchetti, P. A.; Su, Z. B.; Yu, L.

    2017-09-01

    The relation between braid and exclusion statistics is examined in one-dimensional systems, within the framework of Chern-Simons statistical transmutation in gauge invariant form with an appropriate dimensional reduction. If the matter action is anomalous, as for chiral fermions, a relation between braid and exclusion statistics can be established explicitly for both mutual and nonmutual cases. However, if it is not anomalous, the exclusion statistics of emergent low energy excitations is not necessarily connected to the braid statistics of the physical charged fields of the system. Finally, we also discuss the bosonization of one-dimensional anyonic systems through T-duality. Dedicated to the memory of Mario Tonin.

  7. Fractional exclusion and braid statistics in one dimension: a study via dimensional reduction of Chern–Simons theory

    International Nuclear Information System (INIS)

    Ye, Fei; Marchetti, P A; Su, Z B; Yu, L

    2017-01-01

    The relation between braid and exclusion statistics is examined in one-dimensional systems, within the framework of Chern–Simons statistical transmutation in gauge invariant form with an appropriate dimensional reduction. If the matter action is anomalous, as for chiral fermions, a relation between braid and exclusion statistics can be established explicitly for both mutual and nonmutual cases. However, if it is not anomalous, the exclusion statistics of emergent low energy excitations is not necessarily connected to the braid statistics of the physical charged fields of the system. Finally, we also discuss the bosonization of one-dimensional anyonic systems through T-duality. (paper)

  8. Pareto-optimal multi-objective dimensionality reduction deep auto-encoder for mammography classification.

    Science.gov (United States)

    Taghanaki, Saeid Asgari; Kawahara, Jeremy; Miles, Brandon; Hamarneh, Ghassan

    2017-07-01

    Feature reduction is an essential stage in computer aided breast cancer diagnosis systems. Multilayer neural networks can be trained to extract relevant features by encoding high-dimensional data into low-dimensional codes. Optimizing traditional auto-encoders works well only if the initial weights are close to a proper solution. They are also trained to only reduce the mean squared reconstruction error (MRE) between the encoder inputs and the decoder outputs, but do not address the classification error. The goal of the current work is to test the hypothesis that extending traditional auto-encoders (which only minimize reconstruction error) to multi-objective optimization for finding Pareto-optimal solutions provides more discriminative features that will improve classification performance when compared to single-objective and other multi-objective approaches (i.e. scalarized and sequential). In this paper, we introduce a novel multi-objective optimization of deep auto-encoder networks, in which the auto-encoder optimizes two objectives: MRE and mean classification error (MCE) for Pareto-optimal solutions, rather than just MRE. These two objectives are optimized simultaneously by a non-dominated sorting genetic algorithm. We tested our method on 949 X-ray mammograms categorized into 12 classes. The results show that the features identified by the proposed algorithm allow a classification accuracy of up to 98.45%, demonstrating favourable accuracy over the results of state-of-the-art methods reported in the literature. We conclude that adding the classification objective to the traditional auto-encoder objective and optimizing for finding Pareto-optimal solutions, using evolutionary multi-objective optimization, results in producing more discriminative features. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. A method of integration of atomistic simulations and continuum mechanics by collecting of dynamical systems with dimensional reduction

    International Nuclear Information System (INIS)

    Kaczmarek, J.

    2002-01-01

    Elementary processes responsible for phenomena in material are frequently related to scale close to atomic one. Therefore atomistic simulations are important for material sciences. On the other hand continuum mechanics is widely applied in mechanics of materials. It seems inevitable that both methods will gradually integrate. A multiscale method of integration of these approaches called collection of dynamical systems with dimensional reduction is introduced in this work. The dimensional reduction procedure realizes transition between various scale models from an elementary dynamical system (EDS) to a reduced dynamical system (RDS). Mappings which transform variables and forces, skeletal dynamical system (SDS) and a set of approximation and identification methods are main components of this procedure. The skeletal dynamical system is a set of dynamical systems parameterized by some constants and has variables related to the dimensionally reduced model. These constants are identified with the aid of solutions of the elementary dynamical system. As a result we obtain a dimensionally reduced dynamical system which describes phenomena in an averaged way in comparison with the EDS. Concept of integration of atomistic simulations with continuum mechanics consists in using a dynamical system describing evolution of atoms as an elementary dynamical system. Then, we introduce a continuum skeletal dynamical system within the dimensional reduction procedure. In order to construct such a system we have to modify a continuum mechanics formulation to some degree. Namely, we formalize scale of averaging for continuum theory and as a result we consider continuum with finite-dimensional fields only. Then, realization of dimensional reduction is possible. A numerical example of realization of the dimensional reduction procedure is shown. We consider a one dimensional chain of atoms interacting by Lennard-Jones potential. Evolution of this system is described by an elementary

  10. A Novel Four-Dimensional Energy-Saving and Emission-Reduction System and Its Linear Feedback Control

    Directory of Open Access Journals (Sweden)

    Minggang Wang

    2012-01-01

    Full Text Available This paper reports a new four-dimensional energy-saving and emission-reduction chaotic system. The system is obtained in accordance with the complicated relationship between energy saving and emission reduction, carbon emission, economic growth, and new energy development. The dynamics behavior of the system will be analyzed by means of Lyapunov exponents and equilibrium points. Linear feedback control methods are used to suppress chaos to unstable equilibrium. Numerical simulations are presented to show these results.

  11. Reduction of multi-dimensional laboratory data to a two-dimensional plot: a novel technique for the identification of laboratory error.

    Science.gov (United States)

    Kazmierczak, Steven C; Leen, Todd K; Erdogmus, Deniz; Carreira-Perpinan, Miguel A

    2007-01-01

    The clinical laboratory generates large amounts of patient-specific data. Detection of errors that arise during pre-analytical, analytical, and post-analytical processes is difficult. We performed a pilot study, utilizing a multidimensional data reduction technique, to assess the utility of this method for identifying errors in laboratory data. We evaluated 13,670 individual patient records collected over a 2-month period from hospital inpatients and outpatients. We utilized those patient records that contained a complete set of 14 different biochemical analytes. We used two-dimensional generative topographic mapping to project the 14-dimensional record to a two-dimensional space. The use of a two-dimensional generative topographic mapping technique to plot multi-analyte patient data as a two-dimensional graph allows for the rapid identification of potentially anomalous data. Although we performed a retrospective analysis, this technique has the benefit of being able to assess laboratory-generated data in real time, allowing for the rapid identification and correction of anomalous data before they are released to the physician. In addition, serial laboratory multi-analyte data for an individual patient can also be plotted as a two-dimensional plot. This tool might also be useful for assessing patient wellbeing and prognosis.

  12. A Fast and High-precision Orientation Algorithm for BeiDou Based on Dimensionality Reduction

    Directory of Open Access Journals (Sweden)

    ZHAO Jiaojiao

    2015-05-01

    Full Text Available A fast and high-precision orientation algorithm for BeiDou is proposed by deeply analyzing the constellation characteristics of BeiDou and GEO satellites features.With the advantage of good east-west geometry, the baseline vector candidate values were solved by the GEO satellites observations combined with the dimensionality reduction theory at first.Then, we use the ambiguity function to judge the values in order to obtain the optical baseline vector and get the wide lane integer ambiguities. On this basis, the B1 ambiguities were solved. Finally, the high-precision orientation was estimated by the determinating B1 ambiguities. This new algorithm not only can improve the ill-condition of traditional algorithm, but also can reduce the ambiguity search region to a great extent, thus calculating the integer ambiguities in a single-epoch.The algorithm is simulated by the actual BeiDou ephemeris and the result shows that the method is efficient and fast for orientation. It is capable of very high single-epoch success rate(99.31% and accurate attitude angle (the standard deviation of pitch and heading is respectively 0.07°and 0.13°in a real time and dynamic environment.

  13. Dimensionality reduction for the quantitative evaluation of a smartphone-based Timed Up and Go test.

    Science.gov (United States)

    Palmerini, Luca; Mellone, Sabato; Rocchi, Laura; Chiari, Lorenzo

    2011-01-01

    The Timed Up and Go is a clinical test to assess mobility in the elderly and in Parkinson's disease. Lately instrumented versions of the test are being considered, where inertial sensors assess motion. To improve the pervasiveness, ease of use, and cost, we consider a smartphone's accelerometer as the measurement system. Several parameters (usually highly correlated) can be computed from the signals recorded during the test. To avoid redundancy and obtain the features that are most sensitive to the locomotor performance, a dimensionality reduction was performed through principal component analysis (PCA). Forty-nine healthy subjects of different ages were tested. PCA was performed to extract new features (principal components) which are not redundant combinations of the original parameters and account for most of the data variability. They can be useful for exploratory analysis and outlier detection. Then, a reduced set of the original parameters was selected through correlation analysis with the principal components. This set could be recommended for studies based on healthy adults. The proposed procedure could be used as a first-level feature selection in classification studies (i.e. healthy-Parkinson's disease, fallers-non fallers) and could allow, in the future, a complete system for movement analysis to be incorporated in a smartphone.

  14. Visualizing histopathologic deep learning classification and anomaly detection using nonlinear feature space dimensionality reduction.

    Science.gov (United States)

    Faust, Kevin; Xie, Quin; Han, Dominick; Goyle, Kartikay; Volynskaya, Zoya; Djuric, Ugljesa; Diamandis, Phedias

    2018-05-16

    There is growing interest in utilizing artificial intelligence, and particularly deep learning, for computer vision in histopathology. While accumulating studies highlight expert-level performance of convolutional neural networks (CNNs) on focused classification tasks, most studies rely on probability distribution scores with empirically defined cutoff values based on post-hoc analysis. More generalizable tools that allow humans to visualize histology-based deep learning inferences and decision making are scarce. Here, we leverage t-distributed Stochastic Neighbor Embedding (t-SNE) to reduce dimensionality and depict how CNNs organize histomorphologic information. Unique to our workflow, we develop a quantitative and transparent approach to visualizing classification decisions prior to softmax compression. By discretizing the relationships between classes on the t-SNE plot, we show we can super-impose randomly sampled regions of test images and use their distribution to render statistically-driven classifications. Therefore, in addition to providing intuitive outputs for human review, this visual approach can carry out automated and objective multi-class classifications similar to more traditional and less-transparent categorical probability distribution scores. Importantly, this novel classification approach is driven by a priori statistically defined cutoffs. It therefore serves as a generalizable classification and anomaly detection tool less reliant on post-hoc tuning. Routine incorporation of this convenient approach for quantitative visualization and error reduction in histopathology aims to accelerate early adoption of CNNs into generalized real-world applications where unanticipated and previously untrained classes are often encountered.

  15. M-Isomap: Orthogonal Constrained Marginal Isomap for Nonlinear Dimensionality Reduction.

    Science.gov (United States)

    Zhang, Zhao; Chow, Tommy W S; Zhao, Mingbo

    2013-02-01

    Isomap is a well-known nonlinear dimensionality reduction (DR) method, aiming at preserving geodesic distances of all similarity pairs for delivering highly nonlinear manifolds. Isomap is efficient in visualizing synthetic data sets, but it usually delivers unsatisfactory results in benchmark cases. This paper incorporates the pairwise constraints into Isomap and proposes a marginal Isomap (M-Isomap) for manifold learning. The pairwise Cannot-Link and Must-Link constraints are used to specify the types of neighborhoods. M-Isomap computes the shortest path distances over constrained neighborhood graphs and guides the nonlinear DR through separating the interclass neighbors. As a result, large margins between both interand intraclass clusters are delivered and enhanced compactness of intracluster points is achieved at the same time. The validity of M-Isomap is examined by extensive simulations over synthetic, University of California, Irvine, and benchmark real Olivetti Research Library, YALE, and CMU Pose, Illumination, and Expression databases. The data visualization and clustering power of M-Isomap are compared with those of six related DR methods. The visualization results show that M-Isomap is able to deliver more separate clusters. Clustering evaluations also demonstrate that M-Isomap delivers comparable or even better results than some state-of-the-art DR algorithms.

  16. Three-dimensional assemblies of graphene prepared by a novel chemical reduction-induced self-assembly method

    KAUST Repository

    Zhang, Lianbin; Chen, Guoying; Hedhili, Mohamed N.; Zhang, Hongnan; Wang, Peng

    2012-01-01

    In this study, three-dimensional (3D) graphene assemblies are prepared from graphene oxide (GO) by a facile in situ reduction-assembly method, using a novel, low-cost, and environment-friendly reducing medium which is a combination of oxalic acid

  17. Three-dimensional porous hollow fibre copper electrodes for efficient and high-rate electrochemical carbon dioxide reduction

    NARCIS (Netherlands)

    Kas, Recep; Hummadi, Khalid Khazzal; Kortlever, Ruud; de Wit, Patrick; Milbrat, Alexander; Luiten-Olieman, Maria W.J.; Benes, Nieck Edwin; Koper, Marc T.M.; Mul, Guido

    2016-01-01

    Aqueous-phase electrochemical reduction of carbon dioxide requires an active, earth-abundant electrocatalyst, as well as highly efficient mass transport. Here we report the design of a porous hollow fibre copper electrode with a compact three-dimensional geometry, which provides a large area,

  18. Dimensionality Reduction and Information-Theoretic Divergence Between Sets of Ladar Images

    National Research Council Canada - National Science Library

    Gray, David M; Principe, Jose C

    2008-01-01

    ... can be exploited while circumventing many of the problems associated with the so-called "curse of dimensionality." In this study, PCA techniques are used to find a low-dimensional sub-space representation of LADAR image sets...

  19. Dimensional reduction of exceptional E6,E8 gauge groups and flavour chirality

    International Nuclear Information System (INIS)

    Koca, M.

    1984-01-01

    Ten-dimensional Yang - Mills gauge theories based on the exceptional groups E 6 and E 8 are reduced to four-dimensional flavour-chiral Yang - Mills - Higgs theories where the extra six dimensions are identified with the compact G 2 /SU(3) and SO(7)/SO(6) coset spaces. A ten-dimensional E 8 theory leads to three families of SU(5), one of which lies in the 144-dimensional representation of SO(10)

  20. METHOD OF DIMENSIONALITY REDUCTION IN CONTACT MECHANICS AND FRICTION: A USERS HANDBOOK. I. AXIALLY-SYMMETRIC CONTACTS

    Directory of Open Access Journals (Sweden)

    Valentin L. Popov

    2014-04-01

    Full Text Available The Method of Dimensionality Reduction (MDR is a method of calculation and simulation of contacts of elastic and viscoelastic bodies. It consists essentially of two simple steps: (a substitution of the three-dimensional continuum by a uniquely defined one-dimensional linearly elastic or viscoelastic foundation (Winkler foundation and (b transformation of the three-dimensional profile of the contacting bodies by means of the MDR-transformation. As soon as these two steps are completed, the contact problem can be considered to be solved. For axial symmetric contacts, only a small calculation by hand is required which does not exceed elementary calculus and will not be a barrier for any practically-oriented engineer. Alternatively, the MDR can be implemented numerically, which is almost trivial due to the independence of the foundation elements. In spite of their simplicity, all the results are exact. The present paper is a short practical guide to the MDR.

  1. Comparative analysis of nonlinear dimensionality reduction techniques for breast MRI segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Akhbardeh, Alireza; Jacobs, Michael A. [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 (United States); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 (United States) and Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 (United States)

    2012-04-15

    Purpose: Visualization of anatomical structures using radiological imaging methods is an important tool in medicine to differentiate normal from pathological tissue and can generate large amounts of data for a radiologist to read. Integrating these large data sets is difficult and time-consuming. A new approach uses both supervised and unsupervised advanced machine learning techniques to visualize and segment radiological data. This study describes the application of a novel hybrid scheme, based on combining wavelet transform and nonlinear dimensionality reduction (NLDR) methods, to breast magnetic resonance imaging (MRI) data using three well-established NLDR techniques, namely, ISOMAP, local linear embedding (LLE), and diffusion maps (DfM), to perform a comparative performance analysis. Methods: Twenty-five breast lesion subjects were scanned using a 3T scanner. MRI sequences used were T1-weighted, T2-weighted, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging. The hybrid scheme consisted of two steps: preprocessing and postprocessing of the data. The preprocessing step was applied for B{sub 1} inhomogeneity correction, image registration, and wavelet-based image compression to match and denoise the data. In the postprocessing step, MRI parameters were considered data dimensions and the NLDR-based hybrid approach was applied to integrate the MRI parameters into a single image, termed the embedded image. This was achieved by mapping all pixel intensities from the higher dimension to a lower dimensional (embedded) space. For validation, the authors compared the hybrid NLDR with linear methods of principal component analysis (PCA) and multidimensional scaling (MDS) using synthetic data. For the clinical application, the authors used breast MRI data, comparison was performed using the postcontrast DCE MRI image and evaluating the congruence of the segmented lesions. Results: The NLDR-based hybrid approach was able to define and segment

  2. Comparative analysis of nonlinear dimensionality reduction techniques for breast MRI segmentation

    International Nuclear Information System (INIS)

    Akhbardeh, Alireza; Jacobs, Michael A.

    2012-01-01

    Purpose: Visualization of anatomical structures using radiological imaging methods is an important tool in medicine to differentiate normal from pathological tissue and can generate large amounts of data for a radiologist to read. Integrating these large data sets is difficult and time-consuming. A new approach uses both supervised and unsupervised advanced machine learning techniques to visualize and segment radiological data. This study describes the application of a novel hybrid scheme, based on combining wavelet transform and nonlinear dimensionality reduction (NLDR) methods, to breast magnetic resonance imaging (MRI) data using three well-established NLDR techniques, namely, ISOMAP, local linear embedding (LLE), and diffusion maps (DfM), to perform a comparative performance analysis. Methods: Twenty-five breast lesion subjects were scanned using a 3T scanner. MRI sequences used were T1-weighted, T2-weighted, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging. The hybrid scheme consisted of two steps: preprocessing and postprocessing of the data. The preprocessing step was applied for B 1 inhomogeneity correction, image registration, and wavelet-based image compression to match and denoise the data. In the postprocessing step, MRI parameters were considered data dimensions and the NLDR-based hybrid approach was applied to integrate the MRI parameters into a single image, termed the embedded image. This was achieved by mapping all pixel intensities from the higher dimension to a lower dimensional (embedded) space. For validation, the authors compared the hybrid NLDR with linear methods of principal component analysis (PCA) and multidimensional scaling (MDS) using synthetic data. For the clinical application, the authors used breast MRI data, comparison was performed using the postcontrast DCE MRI image and evaluating the congruence of the segmented lesions. Results: The NLDR-based hybrid approach was able to define and segment both

  3. Open reduction and internal fixation aided by intraoperative 3-dimensional imaging improved the articular reduction in 72 displaced acetabular fractures

    DEFF Research Database (Denmark)

    Eckardt, Henrik; Lind, Dennis; Toendevold, Erik

    2015-01-01

    was evaluated on reconstructed coronal and sagittal images of the acetabulum. Results - The fracture severity and patient characteristics were similar in the 2 groups. In the 3D group, 46 of 72 patients (0.6) had a perfect result after open reduction and internal fixation, and in the control group, 17 of 42 (0...

  4. The Multifactor Measure of Performance: Its Development, Norming, and Validation.

    Science.gov (United States)

    Bar-On, Reuven

    2018-01-01

    This article describes the development as well as the initial norming and validation of the Multifactor Measure of Performance™ (MMP™), which is a psychometric instrument that is designed to study, assess and enhance key predictors of human performance to help individuals perform at a higher level. It was created by the author, for the purpose of going beyond existing conceptual and psychometric models that often focus on relatively few factors that are purported to assess performance at school, in the workplace and elsewhere. The relative sparsity of multifactorial pre-employment assessment instruments exemplifies, for the author, one of the important reasons for developing the MMP™, which attempts to comprehensively evaluate a wider array of factors that are thought to contribute to performance. In that this situation creates a need in the area of test-construction that should be addressed, the author sought to develop a multifactorial assessment and development instrument that could concomitantly evaluate a combination of physical, cognitive, intra-personal, inter-personal, and motivational factors that significantly contribute to performance. The specific aim of this article is to show why, how and if this could be done as well as to present and discuss the potential importance of the results obtained to date. The findings presented here will hopefully add to what is known about human performance and thus contribute to the professional literature, in addition to contribute to the continued development of the MMP™. The impetus for developing the MMP™ is first explained below, followed by a detailed description of the process involved and the findings obtained; and their potential application is then discussed as well as the possible limitations of the present research and the need for future studies to address them.

  5. The multi-factor energy input–output model

    International Nuclear Information System (INIS)

    Guevara, Zeus; Domingos, Tiago

    2017-01-01

    Energy input–output analysis (EIO analysis) is a noteworthy tool for the analysis of the role of energy in the economy. However, it has relied on models that provide a limited description of energy flows in the economic system and do not allow an adequate analysis of energy efficiency. This paper introduces a novel energy input–output model, the multi-factor energy input–output model (MF-EIO model), which is obtained from a partitioning of a hybrid-unit input–output system of the economy. This model improves on current models by describing the energy flows according to the processes of energy conversion and the levels of energy use in the economy. It characterizes the vector of total energy output as a function of seven factors: two energy efficiency indicators; two characteristics of end-use energy consumption; and three economic features of the rest of the economy. Moreover, it is consistent with the standard model for EIO analysis, i.e., the hybrid-unit model. This paper also introduces an approximate version of the MF-EIO model, which is equivalent to the former under equal energy prices for industries and final consumers, but requires less data processing. The latter is composed by two linked models: a model of the energy sector in physical units, and a model of the rest of the economy in monetary units. In conclusion, the proposed modelling framework improves EIO analysis and extends EIO applications to the accounting for energy efficiency of the economy. - Highlights: • A novel energy input–output model is introduced. • It allows a more adequate analysis of energy flows than current models. • It describes energy flows according to processes of energy conversion and use. • It can be used for other environmental applications (material use and emissions). • An approximate version of the model is introduced, simpler and less data intensive.

  6. A Dimensionality Reduction-Based Multi-Step Clustering Method for Robust Vessel Trajectory Analysis

    Directory of Open Access Journals (Sweden)

    Huanhuan Li

    2017-08-01

    Full Text Available The Shipboard Automatic Identification System (AIS is crucial for navigation safety and maritime surveillance, data mining and pattern analysis of AIS information have attracted considerable attention in terms of both basic research and practical applications. Clustering of spatio-temporal AIS trajectories can be used to identify abnormal patterns and mine customary route data for transportation safety. Thus, the capacities of navigation safety and maritime traffic monitoring could be enhanced correspondingly. However, trajectory clustering is often sensitive to undesirable outliers and is essentially more complex compared with traditional point clustering. To overcome this limitation, a multi-step trajectory clustering method is proposed in this paper for robust AIS trajectory clustering. In particular, the Dynamic Time Warping (DTW, a similarity measurement method, is introduced in the first step to measure the distances between different trajectories. The calculated distances, inversely proportional to the similarities, constitute a distance matrix in the second step. Furthermore, as a widely-used dimensional reduction method, Principal Component Analysis (PCA is exploited to decompose the obtained distance matrix. In particular, the top k principal components with above 95% accumulative contribution rate are extracted by PCA, and the number of the centers k is chosen. The k centers are found by the improved center automatically selection algorithm. In the last step, the improved center clustering algorithm with k clusters is implemented on the distance matrix to achieve the final AIS trajectory clustering results. In order to improve the accuracy of the proposed multi-step clustering algorithm, an automatic algorithm for choosing the k clusters is developed according to the similarity distance. Numerous experiments on realistic AIS trajectory datasets in the bridge area waterway and Mississippi River have been implemented to compare our

  7. A Dimensionality Reduction-Based Multi-Step Clustering Method for Robust Vessel Trajectory Analysis.

    Science.gov (United States)

    Li, Huanhuan; Liu, Jingxian; Liu, Ryan Wen; Xiong, Naixue; Wu, Kefeng; Kim, Tai-Hoon

    2017-08-04

    The Shipboard Automatic Identification System (AIS) is crucial for navigation safety and maritime surveillance, data mining and pattern analysis of AIS information have attracted considerable attention in terms of both basic research and practical applications. Clustering of spatio-temporal AIS trajectories can be used to identify abnormal patterns and mine customary route data for transportation safety. Thus, the capacities of navigation safety and maritime traffic monitoring could be enhanced correspondingly. However, trajectory clustering is often sensitive to undesirable outliers and is essentially more complex compared with traditional point clustering. To overcome this limitation, a multi-step trajectory clustering method is proposed in this paper for robust AIS trajectory clustering. In particular, the Dynamic Time Warping (DTW), a similarity measurement method, is introduced in the first step to measure the distances between different trajectories. The calculated distances, inversely proportional to the similarities, constitute a distance matrix in the second step. Furthermore, as a widely-used dimensional reduction method, Principal Component Analysis (PCA) is exploited to decompose the obtained distance matrix. In particular, the top k principal components with above 95% accumulative contribution rate are extracted by PCA, and the number of the centers k is chosen. The k centers are found by the improved center automatically selection algorithm. In the last step, the improved center clustering algorithm with k clusters is implemented on the distance matrix to achieve the final AIS trajectory clustering results. In order to improve the accuracy of the proposed multi-step clustering algorithm, an automatic algorithm for choosing the k clusters is developed according to the similarity distance. Numerous experiments on realistic AIS trajectory datasets in the bridge area waterway and Mississippi River have been implemented to compare our proposed method with

  8. Investigating reduction of dimensionality during single-joint elbow movements: a case study on muscle synergies

    Directory of Open Access Journals (Sweden)

    Enrico eChiovetto

    2013-02-01

    Full Text Available A long standing hypothesis in the neuroscience community is that the CNS generates the muscle activities to accomplish movements by combining a relatively small number of stereotyped patterns of muscle activations, often referred to as muscle synergies. Different definitions of synergies have been given in the literature. The most well-known are those of synchronous, time-varying and temporal muscle synergies. Each one of them is based on a different mathematical model used to factor some EMG array recordings collected during the execution of variety of motor tasks into a well-determined spatial, temporal or spatio-temporal organization. This plurality of definitions and their separate application to complex tasks have so far complicated the comparison and interpretation of the results obtained across studies, and it has always remained unclear why and when one synergistic decomposition should be preferred to another one. By using well-understood motor tasks such as elbow flexions and extensions, we aimed in this study to clarify better what are the motor features characterized by each kind of decomposition and to assess whether, when and why one of them should be preferred to the others. We found that three temporal synergies, each one of them accounting for specific temporal phases of the movements could account for the majority of the data variation. Similar performances could be achieved by two synchronous synergies, encoding the agonist-antagonist nature of the two muscles considered, and by two time-varying muscle synergies, encoding each one a task-related feature of the elbow movements, specifically their direction. Our findings support the notion that each EMG decomposition provides a set of well-interpretable muscle synergies, identifying reduction of dimensionality in different aspects of the movements. Taken together, our findings suggest that all decompositions are not equivalent and may imply different neurophysiological substrates

  9. A Novel Medical Freehand Sketch 3D Model Retrieval Method by Dimensionality Reduction and Feature Vector Transformation

    Directory of Open Access Journals (Sweden)

    Zhang Jing

    2016-01-01

    Full Text Available To assist physicians to quickly find the required 3D model from the mass medical model, we propose a novel retrieval method, called DRFVT, which combines the characteristics of dimensionality reduction (DR and feature vector transformation (FVT method. The DR method reduces the dimensionality of feature vector; only the top M low frequency Discrete Fourier Transform coefficients are retained. The FVT method does the transformation of the original feature vector and generates a new feature vector to solve the problem of noise sensitivity. The experiment results demonstrate that the DRFVT method achieves more effective and efficient retrieval results than other proposed methods.

  10. On the dimensional reduction of a gravitational theory containing higher-derivative terms

    International Nuclear Information System (INIS)

    Pollock, M.D.

    1990-02-01

    From the higher-dimensional gravitational theory L-circumflex=R-circumflex-2Λ-circumflex-α-circumflex 1 R-circumflex 2 =α-circumflex 2 R-circumflex AB R-circumflex AB -α-circumflex 3 R-circumflex ABCD R-circumflex ABCD , we derive the effective four-dimensional Lagrangian L. (author). 12 refs

  11. Multi-Factor Impact Analysis of Agricultural Production in Bangladesh with Climate Change

    Science.gov (United States)

    Ruane, Alex C.; Major, David C.; Yu, Winston H.; Alam, Mozaharul; Hussain, Sk. Ghulam; Khan, Abu Saleh; Hassan, Ahmadul; Al Hossain, Bhuiya Md. Tamim; Goldberg, Richard; Horton, Radley M.; hide

    2012-01-01

    Diverse vulnerabilities of Bangladesh's agricultural sector in 16 sub-regions are assessed using experiments designed to investigate climate impact factors in isolation and in combination. Climate information from a suite of global climate models (GCMs) is used to drive models assessing the agricultural impact of changes in temperature, precipitation, carbon dioxide concentrations, river floods, and sea level rise for the 2040-2069 period in comparison to a historical baseline. Using the multi-factor impacts analysis framework developed in Yu et al. (2010), this study provides new sub-regional vulnerability analyses and quantifies key uncertainties in climate and production. Rice (aman, boro, and aus seasons) and wheat production are simulated in each sub-region using the biophysical Crop Environment REsource Synthesis (CERES) models. These simulations are then combined with the MIKE BASIN hydrologic model for river floods in the Ganges-Brahmaputra-Meghna (GBM) Basins, and the MIKE21Two-Dimensional Estuary Model to determine coastal inundation under conditions of higher mean sea level. The impacts of each factor depend on GCM configurations, emissions pathways, sub-regions, and particular seasons and crops. Temperature increases generally reduce production across all scenarios. Precipitation changes can have either a positive or a negative impact, with a high degree of uncertainty across GCMs. Carbon dioxide impacts on crop production are positive and depend on the emissions pathway. Increasing river flood areas reduce production in affected sub-regions. Precipitation uncertainties from different GCMs and emissions scenarios are reduced when integrated across the large GBM Basins' hydrology. Agriculture in Southern Bangladesh is severely affected by sea level rise even when cyclonic surges are not fully considered, with impacts increasing under the higher emissions scenario.

  12. Features in chemical kinetics. I. Signatures of self-emerging dimensional reduction from a general format of the evolution law.

    Science.gov (United States)

    Nicolini, Paolo; Frezzato, Diego

    2013-06-21

    Simplification of chemical kinetics description through dimensional reduction is particularly important to achieve an accurate numerical treatment of complex reacting systems, especially when stiff kinetics are considered and a comprehensive picture of the evolving system is required. To this aim several tools have been proposed in the past decades, such as sensitivity analysis, lumping approaches, and exploitation of time scales separation. In addition, there are methods based on the existence of the so-called slow manifolds, which are hyper-surfaces of lower dimension than the one of the whole phase-space and in whose neighborhood the slow evolution occurs after an initial fast transient. On the other hand, all tools contain to some extent a degree of subjectivity which seems to be irremovable. With reference to macroscopic and spatially homogeneous reacting systems under isothermal conditions, in this work we shall adopt a phenomenological approach to let self-emerge the dimensional reduction from the mathematical structure of the evolution law. By transforming the original system of polynomial differential equations, which describes the chemical evolution, into a universal quadratic format, and making a direct inspection of the high-order time-derivatives of the new dynamic variables, we then formulate a conjecture which leads to the concept of an "attractiveness" region in the phase-space where a well-defined state-dependent rate function ω has the simple evolution ω[over dot]=-ω(2) along any trajectory up to the stationary state. This constitutes, by itself, a drastic dimensional reduction from a system of N-dimensional equations (being N the number of chemical species) to a one-dimensional and universal evolution law for such a characteristic rate. Step-by-step numerical inspections on model kinetic schemes are presented. In the companion paper [P. Nicolini and D. Frezzato, J. Chem. Phys. 138, 234102 (2013)] this outcome will be naturally related to the

  13. Three-dimensional anisotropic adaptive filtering of projection data for noise reduction in cone beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Andreas; Wigstroem, Lars; Hofmann, Hannes G.; Hornegger, Joachim; Zhu Lei; Strobel, Norbert; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States) and Center for Medical Image Science and Visualization, Linkoeping University, Linkoeping (Sweden); Pattern Recognition Laboratory, Department of Computer Science, Friedrich-Alexander University of Erlangen-Nuremberg, 91054, Erlangen (Germany); Nuclear and Radiological Engineering and Medical Physics Programs, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Siemens AG Healthcare, Forchheim 91301 (Germany); Department of Radiology, Stanford University, Stanford, California 94305 (United States)

    2011-11-15

    Purpose: The combination of quickly rotating C-arm gantry with digital flat panel has enabled the acquisition of three-dimensional data (3D) in the interventional suite. However, image quality is still somewhat limited since the hardware has not been optimized for CT imaging. Adaptive anisotropic filtering has the ability to improve image quality by reducing the noise level and therewith the radiation dose without introducing noticeable blurring. By applying the filtering prior to 3D reconstruction, noise-induced streak artifacts are reduced as compared to processing in the image domain. Methods: 3D anisotropic adaptive filtering was used to process an ensemble of 2D x-ray views acquired along a circular trajectory around an object. After arranging the input data into a 3D space (2D projections + angle), the orientation of structures was estimated using a set of differently oriented filters. The resulting tensor representation of local orientation was utilized to control the anisotropic filtering. Low-pass filtering is applied only along structures to maintain high spatial frequency components perpendicular to these. The evaluation of the proposed algorithm includes numerical simulations, phantom experiments, and in-vivo data which were acquired using an AXIOM Artis dTA C-arm system (Siemens AG, Healthcare Sector, Forchheim, Germany). Spatial resolution and noise levels were compared with and without adaptive filtering. A human observer study was carried out to evaluate low-contrast detectability. Results: The adaptive anisotropic filtering algorithm was found to significantly improve low-contrast detectability by reducing the noise level by half (reduction of the standard deviation in certain areas from 74 to 30 HU). Virtually no degradation of high contrast spatial resolution was observed in the modulation transfer function (MTF) analysis. Although the algorithm is computationally intensive, hardware acceleration using Nvidia's CUDA Interface provided an 8

  14. Three-dimensional anisotropic adaptive filtering of projection data for noise reduction in cone beam CT

    International Nuclear Information System (INIS)

    Maier, Andreas; Wigstroem, Lars; Hofmann, Hannes G.; Hornegger, Joachim; Zhu Lei; Strobel, Norbert; Fahrig, Rebecca

    2011-01-01

    Purpose: The combination of quickly rotating C-arm gantry with digital flat panel has enabled the acquisition of three-dimensional data (3D) in the interventional suite. However, image quality is still somewhat limited since the hardware has not been optimized for CT imaging. Adaptive anisotropic filtering has the ability to improve image quality by reducing the noise level and therewith the radiation dose without introducing noticeable blurring. By applying the filtering prior to 3D reconstruction, noise-induced streak artifacts are reduced as compared to processing in the image domain. Methods: 3D anisotropic adaptive filtering was used to process an ensemble of 2D x-ray views acquired along a circular trajectory around an object. After arranging the input data into a 3D space (2D projections + angle), the orientation of structures was estimated using a set of differently oriented filters. The resulting tensor representation of local orientation was utilized to control the anisotropic filtering. Low-pass filtering is applied only along structures to maintain high spatial frequency components perpendicular to these. The evaluation of the proposed algorithm includes numerical simulations, phantom experiments, and in-vivo data which were acquired using an AXIOM Artis dTA C-arm system (Siemens AG, Healthcare Sector, Forchheim, Germany). Spatial resolution and noise levels were compared with and without adaptive filtering. A human observer study was carried out to evaluate low-contrast detectability. Results: The adaptive anisotropic filtering algorithm was found to significantly improve low-contrast detectability by reducing the noise level by half (reduction of the standard deviation in certain areas from 74 to 30 HU). Virtually no degradation of high contrast spatial resolution was observed in the modulation transfer function (MTF) analysis. Although the algorithm is computationally intensive, hardware acceleration using Nvidia's CUDA Interface provided an 8.9-fold

  15. Exploring the effects of dimensionality reduction in deep networks for force estimation in robotic-assisted surgery

    Science.gov (United States)

    Aviles, Angelica I.; Alsaleh, Samar; Sobrevilla, Pilar; Casals, Alicia

    2016-03-01

    Robotic-Assisted Surgery approach overcomes the limitations of the traditional laparoscopic and open surgeries. However, one of its major limitations is the lack of force feedback. Since there is no direct interaction between the surgeon and the tissue, there is no way of knowing how much force the surgeon is applying which can result in irreversible injuries. The use of force sensors is not practical since they impose different constraints. Thus, we make use of a neuro-visual approach to estimate the applied forces, in which the 3D shape recovery together with the geometry of motion are used as input to a deep network based on LSTM-RNN architecture. When deep networks are used in real time, pre-processing of data is a key factor to reduce complexity and improve the network performance. A common pre-processing step is dimensionality reduction which attempts to eliminate redundant and insignificant information by selecting a subset of relevant features to use in model construction. In this work, we show the effects of dimensionality reduction in a real-time application: estimating the applied force in Robotic-Assisted Surgeries. According to the results, we demonstrated positive effects of doing dimensionality reduction on deep networks including: faster training, improved network performance, and overfitting prevention. We also show a significant accuracy improvement, ranging from about 33% to 86%, over existing approaches related to force estimation.

  16. Dimensional reduction of a general advection–diffusion equation in 2D channels

    Science.gov (United States)

    Kalinay, Pavol; Slanina, František

    2018-06-01

    Diffusion of point-like particles in a two-dimensional channel of varying width is studied. The particles are driven by an arbitrary space dependent force. We construct a general recurrence procedure mapping the corresponding two-dimensional advection-diffusion equation onto the longitudinal coordinate x. Unlike the previous specific cases, the presented procedure enables us to find the one-dimensional description of the confined diffusion even for non-conservative (vortex) forces, e.g. caused by flowing solvent dragging the particles. We show that the result is again the generalized Fick–Jacobs equation. Despite of non existing scalar potential in the case of vortex forces, the effective one-dimensional scalar potential, as well as the corresponding quasi-equilibrium and the effective diffusion coefficient can be always found.

  17. The Analysis of Dimensionality Reduction Techniques in Cryptographic Object Code Classification

    Energy Technology Data Exchange (ETDEWEB)

    Jason L. Wright; Milos Manic

    2010-05-01

    This paper compares the application of three different dimension reduction techniques to the problem of locating cryptography in compiled object code. A simple classi?er is used to compare dimension reduction via sorted covariance, principal component analysis, and correlation-based feature subset selection. The analysis concentrates on the classi?cation accuracy as the number of dimensions is increased.

  18. arXiv Supersymmetric gauged matrix models from dimensional reduction on a sphere

    CERN Document Server

    Closset, Cyril; Seong, Rak-Kyeong

    2018-05-04

    It was recently proposed that $ \\mathcal{N} $ = 1 supersymmetric gauged matrix models have a duality of order four — that is, a quadrality — reminiscent of infrared dualities of SQCD theories in higher dimensions. In this note, we show that the zero-dimensional quadrality proposal can be inferred from the two-dimensional Gadde-Gukov-Putrov triality. We consider two-dimensional $ \\mathcal{N} $ = (0, 2) SQCD compactified on a sphere with the half-topological twist. For a convenient choice of R-charge, the zero-mode sector on the sphere gives rise to a simple $ \\mathcal{N} $ = 1 gauged matrix model. Triality on the sphere then implies a triality relation for the supersymmetric matrix model, which can be completed to the full quadrality.

  19. Two-dimensional dynamics of elasto-inertial turbulence and its role in polymer drag reduction

    Science.gov (United States)

    Sid, S.; Terrapon, V. E.; Dubief, Y.

    2018-02-01

    The goal of the present study is threefold: (i) to demonstrate the two-dimensional nature of the elasto-inertial instability in elasto-inertial turbulence (EIT), (ii) to identify the role of the bidimensional instability in three-dimensional EIT flows, and (iii) to establish the role of the small elastic scales in the mechanism of self-sustained EIT. Direct numerical simulations of viscoelastic fluid flows are performed in both two- and three-dimensional straight periodic channels using the Peterlin finitely extensible nonlinear elastic model (FENE-P). The Reynolds number is set to Reτ=85 , which is subcritical for two-dimensional flows but beyond the transition for three-dimensional ones. The polymer properties selected correspond to those of typical dilute polymer solutions, and two moderate Weissenberg numbers, Wiτ=40 ,100 , are considered. The simulation results show that sustained turbulence can be observed in two-dimensional subcritical flows, confirming the existence of a bidimensional elasto-inertial instability. The same type of instability is also observed in three-dimensional simulations where both Newtonian and elasto-inertial turbulent structures coexist. Depending on the Wi number, one type of structure can dominate and drive the flow. For large Wi values, the elasto-inertial instability tends to prevail over the Newtonian turbulence. This statement is supported by (i) the absence of typical Newtonian near-wall vortices and (ii) strong similarities between two- and three-dimensional flows when considering larger Wi numbers. The role of small elastic scales is investigated by introducing global artificial diffusion (GAD) in the hyperbolic transport equation for polymers. The aim is to measure how the flow reacts when the smallest elastic scales are progressively filtered out. The study results show that the introduction of large polymer diffusion in the system strongly damps a significant part of the elastic scales that are necessary to feed

  20. Transformative piezoelectric enhancement of P(VDF-TrFE) synergistically driven by nanoscale dimensional reduction and thermal treatment.

    Science.gov (United States)

    Ico, G; Myung, A; Kim, B S; Myung, N V; Nam, J

    2018-02-08

    Despite the significant potential of organic piezoelectric materials in the electro-mechanical or mechano-electrical applications that require light and flexible material properties, the intrinsically low piezoelectric performance as compared to traditional inorganic materials has limited their full utilization. In this study, we demonstrate that dimensional reduction of poly(vinylidene fluoride trifluoroethylene) (P(VDF-TrFE)) at the nanoscale by electrospinning, combined with an appropriate thermal treatment, induces a transformative enhancement in piezoelectric performance. Specifically, the piezoelectric coefficient (d 33 ) reached up to -108 pm V -1 , approaching that of inorganic counterparts. Electrospun mats composed of thermo-treated 30 nm nanofibers with a thickness of 15 μm produced a consistent peak-to-peak voltage of 38.5 V and a power output of 74.1 μW at a strain of 0.26% while sustaining energy production over 10k repeated actuations. The exceptional piezoelectric performance was realized by the enhancement of piezoelectric dipole alignment and the materialization of flexoelectricity, both from the synergistic effects of dimensional reduction and thermal treatment. Our findings suggest that dimensionally controlled and thermally treated electrospun P(VDF-TrFE) nanofibers provide an opportunity to exploit their flexibility and durability for mechanically challenging applications while matching the piezoelectric performance of brittle, inorganic piezoelectric materials.

  1. Effect evaluation of a multifactor community intervention to reduce falls among older persons

    NARCIS (Netherlands)

    Wijlhuizen, G.J.; Bois, P. du; Dommelen, P. van; Hopman-Rock, M.

    2007-01-01

    The objective of the study was to evaluate the effectiveness of a multifactor and multimethod community intervention programme to reduce falls among older persons by at least 20%. In a pre-test-post test design, self-reported falls were registered for 10 months in the intervention community and two

  2. Cautionary Note on Reporting Eta-Squared Values from Multifactor ANOVA Designs

    Science.gov (United States)

    Pierce, Charles A.; Block, Richard A.; Aguinis, Herman

    2004-01-01

    The authors provide a cautionary note on reporting accurate eta-squared values from multifactor analysis of variance (ANOVA) designs. They reinforce the distinction between classical and partial eta-squared as measures of strength of association. They provide examples from articles published in premier psychology journals in which the authors…

  3. Multifactor Screener in the 2000 National Health Interview Survey Cancer Control Supplement: Uses of Screener Estimates

    Science.gov (United States)

    Dietary intake estimates derived from the Multifactor Screener are rough estimates of usual intake of fruits and vegetables, fiber, calcium, servings of dairy, and added sugar. These estimates are not as accurate as those from more detailed methods (e.g., 24-hour recalls).

  4. Machine Learning Based Dimensionality Reduction Facilitates Ligand Diffusion Paths Assessment: A Case of Cytochrome P450cam.

    Science.gov (United States)

    Rydzewski, J; Nowak, W

    2016-04-12

    In this work we propose an application of a nonlinear dimensionality reduction method to represent the high-dimensional configuration space of the ligand-protein dissociation process in a manner facilitating interpretation. Rugged ligand expulsion paths are mapped into 2-dimensional space. The mapping retains the main structural changes occurring during the dissociation. The topological similarity of the reduced paths may be easily studied using the Fréchet distances, and we show that this measure facilitates machine learning classification of the diffusion pathways. Further, low-dimensional configuration space allows for identification of residues active in transport during the ligand diffusion from a protein. The utility of this approach is illustrated by examination of the configuration space of cytochrome P450cam involved in expulsing camphor by means of enhanced all-atom molecular dynamics simulations. The expulsion trajectories are sampled and constructed on-the-fly during molecular dynamics simulations using the recently developed memetic algorithms [ Rydzewski, J.; Nowak, W. J. Chem. Phys. 2015 , 143 ( 12 ), 124101 ]. We show that the memetic algorithms are effective for enforcing the ligand diffusion and cavity exploration in the P450cam-camphor complex. Furthermore, we demonstrate that machine learning techniques are helpful in inspecting ligand diffusion landscapes and provide useful tools to examine structural changes accompanying rare events.

  5. Parallel accelerated cyclic reduction preconditioner for three-dimensional elliptic PDEs with variable coefficients

    KAUST Repository

    Chavez Chavez, Gustavo Ivan; Turkiyyah, George; Zampini, Stefano; Keyes, David E.

    2017-01-01

    and the cyclic reduction method. The setup and application phases of the preconditioner achieve log-linear complexity in memory footprint and number of operations, and numerical experiments exhibit good weak and strong scalability at large processor counts in a

  6. Dual dimensionality reduction reveals independent encoding of motor features in a muscle synergy for insect flight control.

    Science.gov (United States)

    Sponberg, Simon; Daniel, Thomas L; Fairhall, Adrienne L

    2015-04-01

    What are the features of movement encoded by changing motor commands? Do motor commands encode movement independently or can they be represented in a reduced set of signals (i.e. synergies)? Motor encoding poses a computational and practical challenge because many muscles typically drive movement, and simultaneous electrophysiology recordings of all motor commands are typically not available. Moreover, during a single locomotor period (a stride or wingstroke) the variation in movement may have high dimensionality, even if only a few discrete signals activate the muscles. Here, we apply the method of partial least squares (PLS) to extract the encoded features of movement based on the cross-covariance of motor signals and movement. PLS simultaneously decomposes both datasets and identifies only the variation in movement that relates to the specific muscles of interest. We use this approach to explore how the main downstroke flight muscles of an insect, the hawkmoth Manduca sexta, encode torque during yaw turns. We simultaneously record muscle activity and turning torque in tethered flying moths experiencing wide-field visual stimuli. We ask whether this pair of muscles acts as a muscle synergy (a single linear combination of activity) consistent with their hypothesized function of producing a left-right power differential. Alternatively, each muscle might individually encode variation in movement. We show that PLS feature analysis produces an efficient reduction of dimensionality in torque variation within a wingstroke. At first, the two muscles appear to behave as a synergy when we consider only their wingstroke-averaged torque. However, when we consider the PLS features, the muscles reveal independent encoding of torque. Using these features we can predictably reconstruct the variation in torque corresponding to changes in muscle activation. PLS-based feature analysis provides a general two-sided dimensionality reduction that reveals encoding in high dimensional

  7. Dual dimensionality reduction reveals independent encoding of motor features in a muscle synergy for insect flight control.

    Directory of Open Access Journals (Sweden)

    Simon Sponberg

    2015-04-01

    Full Text Available What are the features of movement encoded by changing motor commands? Do motor commands encode movement independently or can they be represented in a reduced set of signals (i.e. synergies? Motor encoding poses a computational and practical challenge because many muscles typically drive movement, and simultaneous electrophysiology recordings of all motor commands are typically not available. Moreover, during a single locomotor period (a stride or wingstroke the variation in movement may have high dimensionality, even if only a few discrete signals activate the muscles. Here, we apply the method of partial least squares (PLS to extract the encoded features of movement based on the cross-covariance of motor signals and movement. PLS simultaneously decomposes both datasets and identifies only the variation in movement that relates to the specific muscles of interest. We use this approach to explore how the main downstroke flight muscles of an insect, the hawkmoth Manduca sexta, encode torque during yaw turns. We simultaneously record muscle activity and turning torque in tethered flying moths experiencing wide-field visual stimuli. We ask whether this pair of muscles acts as a muscle synergy (a single linear combination of activity consistent with their hypothesized function of producing a left-right power differential. Alternatively, each muscle might individually encode variation in movement. We show that PLS feature analysis produces an efficient reduction of dimensionality in torque variation within a wingstroke. At first, the two muscles appear to behave as a synergy when we consider only their wingstroke-averaged torque. However, when we consider the PLS features, the muscles reveal independent encoding of torque. Using these features we can predictably reconstruct the variation in torque corresponding to changes in muscle activation. PLS-based feature analysis provides a general two-sided dimensionality reduction that reveals encoding in

  8. Vehicle Color Recognition with Vehicle-Color Saliency Detection and Dual-Orientational Dimensionality Reduction of CNN Deep Features

    Science.gov (United States)

    Zhang, Qiang; Li, Jiafeng; Zhuo, Li; Zhang, Hui; Li, Xiaoguang

    2017-12-01

    Color is one of the most stable attributes of vehicles and often used as a valuable cue in some important applications. Various complex environmental factors, such as illumination, weather, noise and etc., result in the visual characteristics of the vehicle color being obvious diversity. Vehicle color recognition in complex environments has been a challenging task. The state-of-the-arts methods roughly take the whole image for color recognition, but many parts of the images such as car windows; wheels and background contain no color information, which will have negative impact on the recognition accuracy. In this paper, a novel vehicle color recognition method using local vehicle-color saliency detection and dual-orientational dimensionality reduction of convolutional neural network (CNN) deep features has been proposed. The novelty of the proposed method includes two parts: (1) a local vehicle-color saliency detection method has been proposed to determine the vehicle color region of the vehicle image and exclude the influence of non-color regions on the recognition accuracy; (2) dual-orientational dimensionality reduction strategy has been designed to greatly reduce the dimensionality of deep features that are learnt from CNN, which will greatly mitigate the storage and computational burden of the subsequent processing, while improving the recognition accuracy. Furthermore, linear support vector machine is adopted as the classifier to train the dimensionality reduced features to obtain the recognition model. The experimental results on public dataset demonstrate that the proposed method can achieve superior recognition performance over the state-of-the-arts methods.

  9. Dual Dimensionality Reduction Reveals Independent Encoding of Motor Features in a Muscle Synergy for Insect Flight Control

    Science.gov (United States)

    Sponberg, Simon; Daniel, Thomas L.; Fairhall, Adrienne L.

    2015-01-01

    What are the features of movement encoded by changing motor commands? Do motor commands encode movement independently or can they be represented in a reduced set of signals (i.e. synergies)? Motor encoding poses a computational and practical challenge because many muscles typically drive movement, and simultaneous electrophysiology recordings of all motor commands are typically not available. Moreover, during a single locomotor period (a stride or wingstroke) the variation in movement may have high dimensionality, even if only a few discrete signals activate the muscles. Here, we apply the method of partial least squares (PLS) to extract the encoded features of movement based on the cross-covariance of motor signals and movement. PLS simultaneously decomposes both datasets and identifies only the variation in movement that relates to the specific muscles of interest. We use this approach to explore how the main downstroke flight muscles of an insect, the hawkmoth Manduca sexta, encode torque during yaw turns. We simultaneously record muscle activity and turning torque in tethered flying moths experiencing wide-field visual stimuli. We ask whether this pair of muscles acts as a muscle synergy (a single linear combination of activity) consistent with their hypothesized function of producing a left-right power differential. Alternatively, each muscle might individually encode variation in movement. We show that PLS feature analysis produces an efficient reduction of dimensionality in torque variation within a wingstroke. At first, the two muscles appear to behave as a synergy when we consider only their wingstroke-averaged torque. However, when we consider the PLS features, the muscles reveal independent encoding of torque. Using these features we can predictably reconstruct the variation in torque corresponding to changes in muscle activation. PLS-based feature analysis provides a general two-sided dimensionality reduction that reveals encoding in high dimensional

  10. Analysis and application of a novel three-dimensional energy-saving and emission-reduction dynamic evolution system

    International Nuclear Information System (INIS)

    Fang, Guochang; Tian, Lixin; Sun, Mei; Fu, Min

    2012-01-01

    A novel three-dimensional energy-saving and emission-reduction chaotic system is proposed, which has not yet been reported in present literature. The system is established in accordance with the complicated relationship between energy-saving and emission-reduction, carbon emissions and economic growth. The dynamic behavior of the system is analyzed by means of Lyapunov exponents and bifurcation diagrams. With undetermined coefficient method, expressions of homoclinic orbits of the system are obtained. The Šilnikov theorem guarantees that the system has Smale horseshoes and the horseshoes chaos. Artificial neural network (ANN) is used to identify the quantitative coefficients in the simulation models according to the statistical data of China, and an empirical study of the real system is carried out with the results in perfect agreement with actual situation. It is found that the sooner and more perfect energy-saving and emission-reduction is started, the easier and sooner the maximum of the carbon emissions will be achieved so as to reduce carbon emissions and energy intensity. Numerical simulations are presented to demonstrate the results. -- Highlights: ► Use non-linear dynamical method to model the energy-saving and emission-reduction system. ► The energy-saving and emission-reduction attractor is obtained. ► Identify the unknown parameters of the energy-saving and emission-reduction system based on the statistical data. ► Evaluating the achievements of energy-saving and emission-reduction by the time-varying energy intensity calculation formula. ► Some statistical results based on the statistical data in China are presented, which are vivid and adherent to the reality.

  11. Green functions and dimensional reduction of quantum fields on product manifolds

    International Nuclear Information System (INIS)

    Haba, Z

    2008-01-01

    We discuss Euclidean Green functions on product manifolds P=N x M. We show that if M is compact and N is not compact then the Euclidean field on P can be approximated by its zero mode which is a Euclidean field on N. We estimate the remainder of this approximation. We show that for large distances on N the remainder is small. If P=R D-1 x S β , where S β is a circle of radius β, then the result reduces to the well-known approximation of the D-dimensional finite temperature quantum field theory by (D - 1)-dimensional one in the high-temperature limit. Analytic continuation of Euclidean fields is discussed briefly

  12. A Comparative Study of 3-Dimensional Titanium Versus 2-Dimensional Titanium Miniplates for Open Reduction and Fixation of Mandibular Parasymphysis Fracture.

    Science.gov (United States)

    Mittal, Yogesh; Varghese, K George; Mohan, S; Jayakumar, N; Chhag, Somil

    2016-03-01

    Three dimensional titanium plating system was developed by Farmand in 1995 to meet the requirements of semi rigid fixation with lesser complication. The purpose of this in vivo prospective study was to evaluate and compare the clinical effectiveness of three dimensional and two dimensional Titanium miniplates for open reduction and fixation of mandibular parasymphysis fracture. Thirty patients with non-comminuted mandibular parasymphysis fractures were divided randomly into two equal groups and were treated with 2 mm 3D and 2D miniplate system respectively. All patients were systematically monitored at 1st, 2nd, 3rd, 6th week, 3rd and 6th month postoperatively. The outcome parameters recorded were severity of pain, infection, mobility, occlusion derangement, paresthesia and implant failure. The data so collected was analyzed using independent t test and Chi square test (α = .05). The results showed that one patient in each group had post-operative infection, occlusion derangement and mobility (p > .05). In Group A, one patient had paresthesia while in Group B, two patients had paresthesia (p > .05). None of the patients in both the groups had implant failure. There was no statistically significant difference between 3D and 2D miniplate system in all the recorded parameters at all the follow-ups (p > .05). 3D miniplates were found to be better than 2D miniplates in terms of cost, ease of surgery and operative time. However, 3D miniplates were unfavorable for cases where fracture line was oblique and in close proximity to mental foramen, where they were difficult to adapt and more chances for tooth-root damage and inadvertent injury to the mental nerve due to traction.

  13. Three-dimensional MRI Analysis of Femoral Head Remodeling After Reduction in Patients With Developmental Dysplasia of the Hip.

    Science.gov (United States)

    Tsukagoshi, Yuta; Kamada, Hiroshi; Kamegaya, Makoto; Takeuchi, Ryoko; Nakagawa, Shogo; Tomaru, Yohei; Tanaka, Kenta; Onishi, Mio; Nishino, Tomofumi; Yamazaki, Masashi

    2018-05-02

    Previous reports on patients with developmental dysplasia of the hip (DDH) showed that the prereduced femoral head was notably smaller and more nonspherical than the intact head, with growth failure observed at the proximal posteromedial area. We evaluated the shape of the femoral head cartilage in patients with DDH before and after reduction, with size and sphericity assessed using 3-dimensional (3D) magnetic resonance imaging (MRI). We studied 10 patients with unilateral DDH (all female) who underwent closed reduction. Patients with avascular necrosis of the femoral head on the plain radiograph 1 year after reduction were excluded. 3D MRI was performed before reduction and after reduction, at 2 years of age. 3D-image analysis software was used to reconstruct the multiplanes. After setting the axial, coronal, and sagittal planes in the software (based on the femoral shaft and neck axes), the smallest sphere that included the femoral head cartilage was drawn, the diameter was measured, and the center of the sphere was defined as the femoral head center. We measured the distance between the center and cartilage surface every 30 degrees on the 3 reconstructed planes. Sphericity of the femoral head was calculated using a ratio (the distance divided by each radius) and compared between prereduction and postreduction. The mean patient age was 7±3 and 26±3 months at the first and second MRI, respectively. The mean duration between the reduction and second MRI was 18±3 months. The femoral head diameter was 26.7±1.5 and 26.0±1.6 mm on the diseased and intact sides, respectively (P=0.069). The ratios of the posteromedial area on the axial plane and the proximoposterior area on the sagittal plane after reduction were significantly larger than before reduction (P<0.01). We demonstrated that the size of the reduced femoral head was nearly equal to that of the intact femoral head and that the growth failure area of the head before reduction, in the proximal posteromedial

  14. On reduction and exact solutions of nonlinear many-dimensional Schroedinger equations

    International Nuclear Information System (INIS)

    Barannik, A.F.; Marchenko, V.A.; Fushchich, V.I.

    1991-01-01

    With the help of the canonical decomposition of an arbitrary subalgebra of the orthogonal algebra AO(n) the rank n and n-1 maximal subalgebras of the extended isochronous Galileo algebra, the rank n maximal subalgebras of the generalized extended classical Galileo algebra AG(a,n) the extended special Galileo algebra AG(2,n) and the extended whole Galileo algebra AG(3,n) are described. By using the rank n subalgebras, ansatze reducing the many dimensional Schroedinger equations to ordinary differential equations is found. With the help of the reduced equation solutions exact solutions of the Schroedinger equation are considered

  15. Dimensional reduction of the Standard Model coupled to a new singlet scalar field

    Energy Technology Data Exchange (ETDEWEB)

    Brauner, Tomáš [Faculty of Science and Technology, University of Stavanger,N-4036 Stavanger (Norway); Tenkanen, Tuomas V.I. [Department of Physics and Helsinki Institute of Physics,P.O. Box 64, FI-00014 University of Helsinki (Finland); Tranberg, Anders [Faculty of Science and Technology, University of Stavanger,N-4036 Stavanger (Norway); Vuorinen, Aleksi [Department of Physics and Helsinki Institute of Physics,P.O. Box 64, FI-00014 University of Helsinki (Finland); Weir, David J. [Faculty of Science and Technology, University of Stavanger,N-4036 Stavanger (Norway); Department of Physics and Helsinki Institute of Physics,P.O. Box 64, FI-00014 University of Helsinki (Finland)

    2017-03-01

    We derive an effective dimensionally reduced theory for the Standard Model augmented by a real singlet scalar. We treat the singlet as a superheavy field and integrate it out, leaving an effective theory involving only the Higgs and SU(2){sub L}×U(1){sub Y} gauge fields, identical to the one studied previously for the Standard Model. This opens up the possibility of efficiently computing the order and strength of the electroweak phase transition, numerically and nonperturbatively, in this extension of the Standard Model. Understanding the phase diagram is crucial for models of electroweak baryogenesis and for studying the production of gravitational waves at thermal phase transitions.

  16. Algorithm for statistical noise reduction in three-dimensional ion implant simulations

    International Nuclear Information System (INIS)

    Hernandez-Mangas, J.M.; Arias, J.; Jaraiz, M.; Bailon, L.; Barbolla, J.

    2001-01-01

    As integrated circuit devices scale into the deep sub-micron regime, ion implantation will continue to be the primary means of introducing dopant atoms into silicon. Different types of impurity profiles such as ultra-shallow profiles and retrograde profiles are necessary for deep submicron devices in order to realize the desired device performance. A new algorithm to reduce the statistical noise in three-dimensional ion implant simulations both in the lateral and shallow/deep regions of the profile is presented. The computational effort in BCA Monte Carlo ion implant simulation is also reduced

  17. Implementation of the Principal Component Analysis onto High-Performance Computer Facilities for Hyperspectral Dimensionality Reduction: Results and Comparisons

    Directory of Open Access Journals (Sweden)

    Ernestina Martel

    2018-06-01

    Full Text Available Dimensionality reduction represents a critical preprocessing step in order to increase the efficiency and the performance of many hyperspectral imaging algorithms. However, dimensionality reduction algorithms, such as the Principal Component Analysis (PCA, suffer from their computationally demanding nature, becoming advisable for their implementation onto high-performance computer architectures for applications under strict latency constraints. This work presents the implementation of the PCA algorithm onto two different high-performance devices, namely, an NVIDIA Graphics Processing Unit (GPU and a Kalray manycore, uncovering a highly valuable set of tips and tricks in order to take full advantage of the inherent parallelism of these high-performance computing platforms, and hence, reducing the time that is required to process a given hyperspectral image. Moreover, the achieved results obtained with different hyperspectral images have been compared with the ones that were obtained with a field programmable gate array (FPGA-based implementation of the PCA algorithm that has been recently published, providing, for the first time in the literature, a comprehensive analysis in order to highlight the pros and cons of each option.

  18. Three-dimensional iron, nitrogen-doped carbon foams as efficient electrocatalysts for oxygen reduction reaction in alkaline solution

    International Nuclear Information System (INIS)

    Ma, Yanjiao; Wang, Hui; Feng, Hanqing; Ji, Shan; Mao, Xuefeng; Wang, Rongfang

    2014-01-01

    Graphical abstract: Three-dimentional Fe, N-doped carbon foams prepared by two steps exhibited comparable catalytic activity for oxygen reduction reaction to commercial Pt/C due to the unique structure and the synergistic effect of Fe and N atoms. - Highlights: • Three-dimensional Fe, N-doped carbon foam (3D-CF) were prepared. • 3D-CF exhibits comparable catalytic activity to Pt/C for oxygen reduction reaction. • The enhanced activity of 3D-CF results of its unique structure. - Abstract: Three-dimensional (3D) Fe, N-doped carbon foams (3D-CF) as efficient cathode catalysts for the oxygen reduction reaction (ORR) in alkaline solution are reported. The 3D-CF exhibit interconnected hierarchical pore structure. In addition, Fe, N-doped carbon without porous strucuture (Fe-N-C) and 3D N-doped carbon without Fe (3D-CF’) are prepared to verify the electrocatalytic activity of 3D-CF. The electrocatalytic performance of as-prepared 3D-CF for ORR shows that the onset potential on 3D-CF electrode positively shifts about 41 mV than those of 3D-CF’ and Fe-N-C respectively. In addition, the onset potential on 3D-CF electrode for ORR is about 27 mV more negative than that on commercial Pt/C electrode. 3D-CF also show better methanol tolerance and durability than commercial Pt/C catalyst. These results show that to synthesize 3D hierarchical pores with high specific surface area is an efficient way to improve the ORR performance

  19. Dimensional reduction of a Lorentz and CPT-violating Maxwell-Chern-Simons model

    Energy Technology Data Exchange (ETDEWEB)

    Belich, H. Jr.; Helayel Neto, J.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas; Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); E-mails: belich@cbpf.br; helayel@cbpf.br; Ferreira, M.M. Jr. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); Maranhao Univ., Sao Luiz, MA (Brazil). Dept. de Fisica]. E-mail: manojr@cbpf.br; Orlando, M.T.D. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); Espirito Santo Univ., Vitoria, ES (Brazil). Dept. de Fisica e Quimica; E-mail: orlando@cce.ufes.br

    2003-01-01

    Taking as starting point a Lorentz and CPT non-invariant Chern-Simons-like model defined in 1+3 dimensions, we proceed realizing its dimensional to D = 1+2. One then obtains a new planar model, composed by the Maxwell-Chern-Simons (MCS) sector, a Klein-Gordon massless scalar field, and a coupling term that mixes the gauge field to the external vector, {nu}{sup {mu}}. In spite of breaking Lorentz invariance in the particle frame, this model may preserve the CPT symmetry for a single particular choice of {nu}{sup {mu}} . Analyzing the dispersion relations, one verifies that the reduced model exhibits stability, but the causality can be jeopardized by some modes. The unitary of the gauge sector is assured without any restriction , while the scalar sector is unitary only in the space-like case. (author)

  20. Feature Space Dimensionality Reduction for Real-Time Vision-Based Food Inspection

    Directory of Open Access Journals (Sweden)

    Mai Moussa CHETIMA

    2009-03-01

    Full Text Available Machine vision solutions are becoming a standard for quality inspection in several manufacturing industries. In the processed-food industry where the appearance attributes of the product are essential to customer’s satisfaction, visual inspection can be reliably achieved with machine vision. But such systems often involve the extraction of a larger number of features than those actually needed to ensure proper quality control, making the process less efficient and difficult to tune. This work experiments with several feature selection techniques in order to reduce the number of attributes analyzed by a real-time vision-based food inspection system. Identifying and removing as much irrelevant and redundant information as possible reduces the dimensionality of the data and allows classification algorithms to operate faster. In some cases, accuracy on classification can even be improved. Filter-based and wrapper-based feature selectors are experimentally evaluated on different bakery products to identify the best performing approaches.

  1. Reduction of the dimensionality and comparative analysis of multivariate radiological data

    International Nuclear Information System (INIS)

    Seddeek, M.K.; Kozae, A.M.; Sharshar, T.; Badran, H.M.

    2009-01-01

    Computational methods were used to reduce the dimensionality and to find clusters of multivariate data. The variables were the natural radioactivity contents and the texture characteristics of sand samples. The application of discriminate analysis revealed that samples with high negative values of the former score have the highest contamination with black sand. Principal component analysis (PCA) revealed that radioactivity concentrations alone are sufficient for the classification. Rough set analysis (RSA) showed that the concentration of 238 U, 226 Ra or 232 Th, combined with the concentration of 40 K, can specify the clusters and characteristics of the sand. Both PCA and RSA show that 238 U, 226 Ra and 232 Th behave similarly. RSA revealed that one or two of them can be omitted without degrading predictions.

  2. Dimensional reduction of a Lorentz and CPT-violating Maxwell-Chern-Simons model

    International Nuclear Information System (INIS)

    Belich, H. Jr.; Helayel Neto, J.A.; Ferreira, M.M. Jr.; Maranhao Univ., Sao Luiz, MA; Orlando, M.T.D.; Espirito Santo Univ., Vitoria, ES

    2003-01-01

    Taking as starting point a Lorentz and CPT non-invariant Chern-Simons-like model defined in 1+3 dimensions, we proceed realizing its dimensional to D = 1+2. One then obtains a new planar model, composed by the Maxwell-Chern-Simons (MCS) sector, a Klein-Gordon massless scalar field, and a coupling term that mixes the gauge field to the external vector, ν μ . In spite of breaking Lorentz invariance in the particle frame, this model may preserve the CPT symmetry for a single particular choice of ν μ . Analyzing the dispersion relations, one verifies that the reduced model exhibits stability, but the causality can be jeopardized by some modes. The unitary of the gauge sector is assured without any restriction , while the scalar sector is unitary only in the space-like case. (author)

  3. An MPCA/LDA Based Dimensionality Reduction Algorithm for Face Recognition

    Directory of Open Access Journals (Sweden)

    Jun Huang

    2014-01-01

    Full Text Available We proposed a face recognition algorithm based on both the multilinear principal component analysis (MPCA and linear discriminant analysis (LDA. Compared with current traditional existing face recognition methods, our approach treats face images as multidimensional tensor in order to find the optimal tensor subspace for accomplishing dimension reduction. The LDA is used to project samples to a new discriminant feature space, while the K nearest neighbor (KNN is adopted for sample set classification. The results of our study and the developed algorithm are validated with face databases ORL, FERET, and YALE and compared with PCA, MPCA, and PCA + LDA methods, which demonstrates an improvement in face recognition accuracy.

  4. Rough electricity: a new fractal multi-factor model of electricity spot prices

    DEFF Research Database (Denmark)

    Bennedsen, Mikkel

    We introduce a new mathematical model of electricity spot prices which accounts for the most important stylized facts of these time series: seasonality, spikes, stochastic volatility and mean reversion. Empirical studies have found a possible fifth stylized fact, fractality, and our approach...... explicitly incorporates this into the model of the prices. Our setup generalizes the popular Ornstein Uhlenbeck-based multi-factor framework of Benth et al. (2007) and allows us to perform statistical tests to distinguish between an Ornstein Uhlenbeck-based model and a fractal model. Further, through...... the multi-factor approach we account for seasonality and spikes before estimating - and making inference on - the degree of fractality. This is novel in the literature and we present simulation evidence showing that these precautions are crucial to accurate estimation. Lastly, we estimate our model...

  5. The Research of Regression Method for Forecasting Monthly Electricity Sales Considering Coupled Multi-factor

    Science.gov (United States)

    Wang, Jiangbo; Liu, Junhui; Li, Tiantian; Yin, Shuo; He, Xinhui

    2018-01-01

    The monthly electricity sales forecasting is a basic work to ensure the safety of the power system. This paper presented a monthly electricity sales forecasting method which comprehensively considers the coupled multi-factors of temperature, economic growth, electric power replacement and business expansion. The mathematical model is constructed by using regression method. The simulation results show that the proposed method is accurate and effective.

  6. Synthesis of molecular hexatechnetium clusters by means of dimensional reduction of their polymeric complexes

    International Nuclear Information System (INIS)

    Ikai, T.; Yoshimura, T.; Shinohara, A.; Takayama, T.; Sekine, T.

    2006-01-01

    Selenide capping hexatechnetium cluster complex [Tc 6 (μ 3 -Se) 8 CN 6 ] 4- (1) was prepared by the reactions of one-dimensional polymer complex [Tc 6 (μ 3 -Se) 8 Br 4 ] 2- and cyanides at high temperature. Similar reaction of sulfide capping hexatechnetium cluster complex, [Tc 6 (μ 3 -S) 8 Br 6 ] 4- with cyanide gave the terminal substituted complex [Tc 6 (μ 3 -S) 8 CN 6 ] 4- (2). The single-crystal X-ray analysis of 1 and 2, showed that the Tc-Tc bond lengths become longer with lager ionic radius of the face capping ligands in the order S -1 , and that of 2 showed it at 2119 cm -1 . Each of cyclic voltammogram of 1 and 2 showed a reversible one electron redox wave assignable to the Tc 6 III /Tc 5 III Tc IV process. These redox potentials shift to the positive about 0.4V compared to those of the Re cluster analogs. (author)

  7. Quantification of Artifact Reduction With Real-Time Cine Four-Dimensional Computed Tomography Acquisition Methods

    International Nuclear Information System (INIS)

    Langner, Ulrich W.; Keall, Paul J.

    2010-01-01

    Purpose: To quantify the magnitude and frequency of artifacts in simulated four-dimensional computed tomography (4D CT) images using three real-time acquisition methods- direction-dependent displacement acquisition, simultaneous displacement and phase acquisition, and simultaneous displacement and velocity acquisition- and to compare these methods with commonly used retrospective phase sorting. Methods and Materials: Image acquisition for the four 4D CT methods was simulated with different displacement and velocity tolerances for spheres with radii of 0.5 cm, 1.5 cm, and 2.5 cm, using 58 patient-measured tumors and respiratory motion traces. The magnitude and frequency of artifacts, CT doses, and acquisition times were computed for each method. Results: The mean artifact magnitude was 50% smaller for the three real-time methods than for retrospective phase sorting. The dose was ∼50% lower, but the acquisition time was 20% to 100% longer for the real-time methods than for retrospective phase sorting. Conclusions: Real-time acquisition methods can reduce the frequency and magnitude of artifacts in 4D CT images, as well as the imaging dose, but they increase the image acquisition time. The results suggest that direction-dependent displacement acquisition is the preferred real-time 4D CT acquisition method, because on average, the lowest dose is delivered to the patient and the acquisition time is the shortest for the resulting number and magnitude of artifacts.

  8. Parallel accelerated cyclic reduction preconditioner for three-dimensional elliptic PDEs with variable coefficients

    KAUST Repository

    Chavez Chavez, Gustavo Ivan

    2017-12-07

    We present a robust and scalable preconditioner for the solution of large-scale linear systems that arise from the discretization of elliptic PDEs amenable to rank compression. The preconditioner is based on hierarchical low-rank approximations and the cyclic reduction method. The setup and application phases of the preconditioner achieve log-linear complexity in memory footprint and number of operations, and numerical experiments exhibit good weak and strong scalability at large processor counts in a distributed memory environment. Numerical experiments with linear systems that feature symmetry and nonsymmetry, definiteness and indefiniteness, constant and variable coefficients demonstrate the preconditioner applicability and robustness. Furthermore, it is possible to control the number of iterations via the accuracy threshold of the hierarchical matrix approximations and their arithmetic operations, and the tuning of the admissibility condition parameter. Together, these parameters allow for optimization of the memory requirements and performance of the preconditioner.

  9. Security enhanced multi-factor biometric authentication scheme using bio-hash function.

    Directory of Open Access Journals (Sweden)

    Younsung Choi

    Full Text Available With the rapid development of personal information and wireless communication technology, user authentication schemes have been crucial to ensure that wireless communications are secure. As such, various authentication schemes with multi-factor authentication have been proposed to improve the security of electronic communications. Multi-factor authentication involves the use of passwords, smart cards, and various biometrics to provide users with the utmost privacy and data protection. Cao and Ge analyzed various authentication schemes and found that Younghwa An's scheme was susceptible to a replay attack where an adversary masquerades as a legal server and a user masquerading attack where user anonymity is not provided, allowing an adversary to execute a password change process by intercepting the user's ID during login. Cao and Ge improved upon Younghwa An's scheme, but various security problems remained. This study demonstrates that Cao and Ge's scheme is susceptible to a biometric recognition error, slow wrong password detection, off-line password attack, user impersonation attack, ID guessing attack, a DoS attack, and that their scheme cannot provide session key agreement. Then, to address all weaknesses identified in Cao and Ge's scheme, this study proposes a security enhanced multi-factor biometric authentication scheme and provides a security analysis and formal analysis using Burrows-Abadi-Needham logic. Finally, the efficiency analysis reveals that the proposed scheme can protect against several possible types of attacks with only a slightly high computational cost.

  10. Security enhanced multi-factor biometric authentication scheme using bio-hash function

    Science.gov (United States)

    Lee, Youngsook; Moon, Jongho

    2017-01-01

    With the rapid development of personal information and wireless communication technology, user authentication schemes have been crucial to ensure that wireless communications are secure. As such, various authentication schemes with multi-factor authentication have been proposed to improve the security of electronic communications. Multi-factor authentication involves the use of passwords, smart cards, and various biometrics to provide users with the utmost privacy and data protection. Cao and Ge analyzed various authentication schemes and found that Younghwa An’s scheme was susceptible to a replay attack where an adversary masquerades as a legal server and a user masquerading attack where user anonymity is not provided, allowing an adversary to execute a password change process by intercepting the user’s ID during login. Cao and Ge improved upon Younghwa An’s scheme, but various security problems remained. This study demonstrates that Cao and Ge’s scheme is susceptible to a biometric recognition error, slow wrong password detection, off-line password attack, user impersonation attack, ID guessing attack, a DoS attack, and that their scheme cannot provide session key agreement. Then, to address all weaknesses identified in Cao and Ge’s scheme, this study proposes a security enhanced multi-factor biometric authentication scheme and provides a security analysis and formal analysis using Burrows-Abadi-Needham logic. Finally, the efficiency analysis reveals that the proposed scheme can protect against several possible types of attacks with only a slightly high computational cost. PMID:28459867

  11. Security enhanced multi-factor biometric authentication scheme using bio-hash function.

    Science.gov (United States)

    Choi, Younsung; Lee, Youngsook; Moon, Jongho; Won, Dongho

    2017-01-01

    With the rapid development of personal information and wireless communication technology, user authentication schemes have been crucial to ensure that wireless communications are secure. As such, various authentication schemes with multi-factor authentication have been proposed to improve the security of electronic communications. Multi-factor authentication involves the use of passwords, smart cards, and various biometrics to provide users with the utmost privacy and data protection. Cao and Ge analyzed various authentication schemes and found that Younghwa An's scheme was susceptible to a replay attack where an adversary masquerades as a legal server and a user masquerading attack where user anonymity is not provided, allowing an adversary to execute a password change process by intercepting the user's ID during login. Cao and Ge improved upon Younghwa An's scheme, but various security problems remained. This study demonstrates that Cao and Ge's scheme is susceptible to a biometric recognition error, slow wrong password detection, off-line password attack, user impersonation attack, ID guessing attack, a DoS attack, and that their scheme cannot provide session key agreement. Then, to address all weaknesses identified in Cao and Ge's scheme, this study proposes a security enhanced multi-factor biometric authentication scheme and provides a security analysis and formal analysis using Burrows-Abadi-Needham logic. Finally, the efficiency analysis reveals that the proposed scheme can protect against several possible types of attacks with only a slightly high computational cost.

  12. Dimensional reduction of U(1) x SU(2) Chern-Simons bosonization: Application to the t - J model

    International Nuclear Information System (INIS)

    Marchetti, P.A.

    1996-09-01

    We perform a dimensional reduction of the U(1) x SU(2) Chern-Simons bosonization and apply it to the t - J model, relevant for high T c superconductors. This procedure yields a decomposition of the electron field into a product of two ''semionic'' fields, i.e. fields obeying Abelian braid statistics with statistics parameter θ = 1/4, one carrying the charge and the other the spin degrees of freedom. A mean field theory is then shown to reproduce correctly the large distance behaviour of the correlation functions of the 1D t - J model at >> J. This result shows that to capture the essential physical properties of the model one needs a specific ''semionic'' form of spin-charge separation. (author). 31 refs

  13. On the integrability of a Hamiltonian reduction of a 2+1-dimensional non-isothermal rotating gas cloud system

    International Nuclear Information System (INIS)

    Rogers, C; Schief, W K

    2011-01-01

    A 2+1-dimensional version of a non-isothermal gas dynamic system with origins in the work of Ovsiannikov and Dyson on spinning gas clouds is shown to admit a Hamiltonian reduction which is completely integrable when the adiabatic index γ = 2. This nonlinear dynamical subsystem is obtained via an elliptic vortex ansatz which is intimately related to the construction of a Lax pair in the integrable case. The general solution of the gas dynamic system is derived in terms of Weierstrass (elliptic) functions. The latter derivation makes use of a connection with a stationary nonlinear Schrödinger equation and a Steen–Ermakov–Pinney equation, the superposition principle of which is based on the classical Lamé equation

  14. Unlocking the Electrocatalytic Activity of Antimony for CO2 Reduction by Two-Dimensional Engineering of the Bulk Material.

    Science.gov (United States)

    Li, Fengwang; Xue, Mianqi; Li, Jiezhen; Ma, Xinlei; Chen, Lu; Zhang, Xueji; MacFarlane, Douglas R; Zhang, Jie

    2017-11-13

    Two-dimensional (2D) materials are known to be useful in catalysis. Engineering 3D bulk materials into the 2D form can enhance the exposure of the active edge sites, which are believed to be the origin of the high catalytic activity. Reported herein is the production of 2D "few-layer" antimony (Sb) nanosheets by cathodic exfoliation. Application of this 2D engineering method turns Sb, an inactive material for CO 2 reduction in its bulk form, into an active 2D electrocatalyst for reduction of CO 2 to formate with high efficiency. The high activity is attributed to the exposure of a large number of catalytically active edge sites. Moreover, this cathodic exfoliation process can be coupled with the anodic exfoliation of graphite in a single-compartment cell for in situ production of a few-layer Sb nanosheets and graphene composite. The observed increased activity of this composite is attributed to the strong electronic interaction between graphene and Sb. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Three-dimensional assemblies of graphene prepared by a novel chemical reduction-induced self-assembly method

    KAUST Repository

    Zhang, Lianbin

    2012-01-01

    In this study, three-dimensional (3D) graphene assemblies are prepared from graphene oxide (GO) by a facile in situ reduction-assembly method, using a novel, low-cost, and environment-friendly reducing medium which is a combination of oxalic acid (OA) and sodium iodide (NaI). It is demonstrated that the combination of a reducing acid, OA, and NaI is indispensable for effective reduction of GO in the current study and this unique combination (1) allows for tunable control over the volume of the thus-prepared graphene assemblies and (2) enables 3D graphene assemblies to be prepared from the GO suspension with a wide range of concentrations (0.1 to 4.5 mg mL-1). To the best of our knowledge, the GO concentration of 0.1 mg mL-1 is the lowest GO concentration ever reported for preparation of 3D graphene assemblies. The thus-prepared 3D graphene assemblies exhibit low density, highly porous structures, and electrically conducting properties. As a proof of concept, we show that by infiltrating a responsive polymer of polydimethylsiloxane (PDMS) into the as-resulted 3D conducting network of graphene, a conducting composite is obtained, which can be used as a sensing device for differentiating organic solvents with different polarity. © 2012 The Royal Society of Chemistry.

  16. Density prediction and dimensionality reduction of mid-term electricity demand in China: A new semiparametric-based additive model

    International Nuclear Information System (INIS)

    Shao, Zhen; Yang, Shan-Lin; Gao, Fei

    2014-01-01

    Highlights: • A new stationary time series smoothing-based semiparametric model is established. • A novel semiparametric additive model based on piecewise smooth is proposed. • We model the uncertainty of data distribution for mid-term electricity forecasting. • We provide efficient long horizon simulation and extraction for external variables. • We provide stable and accurate density predictions for mid-term electricity demand. - Abstract: Accurate mid-term electricity demand forecasting is critical for efficient electric planning, budgeting and operating decisions. Mid-term electricity demand forecasting is notoriously complicated, since the demand is subject to a range of external drivers, such as climate change, economic development, which will exhibit monthly, seasonal, and annual complex variations. Conventional models are based on the assumption that original data is stable and normally distributed, which is generally insignificant in explaining actual demand pattern. This paper proposes a new semiparametric additive model that, in addition to considering the uncertainty of the data distribution, includes practical discussions covering the applications of the external variables. To effectively detach the multi-dimensional volatility of mid-term demand, a novel piecewise smooth method which allows reduction of the data dimensionality is developed. Besides, a semi-parametric procedure that makes use of bootstrap algorithm for density forecast and model estimation is presented. Two typical cases in China are presented to verify the effectiveness of the proposed methodology. The results suggest that both meteorological and economic variables play a critical role in mid-term electricity consumption prediction in China, while the extracted economic factor is adequate to reveal the potentially complex relationship between electricity consumption and economic fluctuation. Overall, the proposed model can be easily applied to mid-term demand forecasting, and

  17. Effect of Intraoperative Three-Dimensional Imaging During the Reduction and Fixation of Displaced Calcaneal Fractures on Articular Congruence and Implant Fixation

    DEFF Research Database (Denmark)

    Eckardt, Henrik; Lind, Marianne

    2015-01-01

    BACKGROUND: Operative treatment of displaced calcaneal fractures should restore joint congruence, but conventional fluoroscopy is unable to fully visualize the subtalar joint. We questioned whether intraoperative 3-dimensional (3D) imaging would aid in the reduction of calcaneal fractures......, resulting in improved articular congruence and implant positioning. METHOD: Sixty-two displaced calcaneal fractures were operated on using standard fluoroscopic views. When the surgeon had achieved a satisfactory reduction, an intraoperative 3D scan was conducted, malreductions or implant imperfections were...

  18. Dynamic Multi-Factor Credit Risk Model with Fat-Tailed Factors

    Czech Academy of Sciences Publication Activity Database

    Gapko, Petr; Šmíd, Martin

    2012-01-01

    Roč. 62, č. 2 (2012), s. 125-140 ISSN 0015-1920 R&D Projects: GA ČR GD402/09/H045; GA ČR GA402/09/0965 Grant - others:Univerzita Karlova(CZ) GAUK 46108 Institutional research plan: CEZ:AV0Z10750506 Keywords : credit risk * probability of default * loss given default * credit loss * credit loss distribution * Basel II Subject RIV: AH - Economics Impact factor: 0.340, year: 2012 http://library.utia.cas.cz/separaty/2012/E/smid-dynamic multi-factor credit risk model with fat-tailed factors.pdf

  19. Quality management of airport services – An analysis of the multifactor structure of customer satisfaction

    Directory of Open Access Journals (Sweden)

    Josip Mikulić

    2007-07-01

    Full Text Available The purpose of this paper is to get an insight into the multifactor structure of satisfaction of the customers of a Croatian airport. Based on data from the primary research (n=1053, an importance-performance analysis was conducted that resulted in the categorization of airport services into the satisfaction factors according to Kano’s model of quality. Basic factors, performance factors and excitement factors were identified. The results of this analysis enrich the standard information basis which is obtained through customer satisfaction surveys. Furthermore, they represent a valuable resource for decision-making within the domain of service quality management.

  20. Assessment of Multifactor Gene-Environment Interactions and Ovarian Cancer Risk

    DEFF Research Database (Denmark)

    Usset, Joseph L; Raghavan, Rama; Tyrer, Jonathan P

    2016-01-01

    and non-obese women. METHODS: We considered interactions between 11,441 SNPs within 80 candidate genes related to hormone biosynthesis and metabolism and insulin-like growth factors with six hormone-related factors (oral contraceptive use, parity, endometriosis, tubal ligation, hormone replacement therapy...... Future work is needed to develop powerful statistical methods able to detect these complex interactions. IMPACT: Assessment of multifactor interaction is feasible, and, here, suggests that the relationship between genetic variants within candidate genes and hormone-related risk factors may vary EOC...

  1. Reduction of metal artifact in three-dimensional computed tomography (3D CT) with dental impression materials.

    Science.gov (United States)

    Park, W S; Kim, K D; Shin, H K; Lee, S H

    2007-01-01

    Metal Artifact still remains one of the main drawbacks in craniofacial Three-Dimensional Computed Tomography (3D CT). In this study, we tried to test the efficacy of additional silicone dental impression materials as a "tooth shield" for the reduction of metal artifact caused by metal restorations and orthodontic appliances. 6 phantoms with 4 teeth were prepared for this in vitro study. Orthodontic bracket, bands and amalgam restorations were placed in each tooth to reproduce various intraoral conditions. Standardized silicone shields were fabricated and placed around the teeth. CT image acquisition was performed with and without silicone shields. Maximum value, mean, and standard deviation of Hounsfield Units (HU) were compared with the presence of silicone shields. In every situation, metal artifacts were reduced in quality and quantity when silicone shields are used. Amalgam restoration made most serious metal artifact. Silicone shields made by dental impression material might be effective way to reduce the metal artifact caused by dental restoration and orthodontic appliances. This will help more excellent 3D image from 3D CT in craniofacial area.

  2. An iterated Laplacian based semi-supervised dimensionality reduction for classification of breast cancer on ultrasound images.

    Science.gov (United States)

    Liu, Xiao; Shi, Jun; Zhou, Shichong; Lu, Minhua

    2014-01-01

    The dimensionality reduction is an important step in ultrasound image based computer-aided diagnosis (CAD) for breast cancer. A newly proposed l2,1 regularized correntropy algorithm for robust feature selection (CRFS) has achieved good performance for noise corrupted data. Therefore, it has the potential to reduce the dimensions of ultrasound image features. However, in clinical practice, the collection of labeled instances is usually expensive and time costing, while it is relatively easy to acquire the unlabeled or undetermined instances. Therefore, the semi-supervised learning is very suitable for clinical CAD. The iterated Laplacian regularization (Iter-LR) is a new regularization method, which has been proved to outperform the traditional graph Laplacian regularization in semi-supervised classification and ranking. In this study, to augment the classification accuracy of the breast ultrasound CAD based on texture feature, we propose an Iter-LR-based semi-supervised CRFS (Iter-LR-CRFS) algorithm, and then apply it to reduce the feature dimensions of ultrasound images for breast CAD. We compared the Iter-LR-CRFS with LR-CRFS, original supervised CRFS, and principal component analysis. The experimental results indicate that the proposed Iter-LR-CRFS significantly outperforms all other algorithms.

  3. Integration of metabolomics and proteomics in molecular plant physiology--coping with the complexity by data-dimensionality reduction.

    Science.gov (United States)

    Weckwerth, Wolfram

    2008-02-01

    In recent years, genomics has been extended to functional genomics. Toward the characterization of organisms or species on the genome level, changes on the metabolite and protein level have been shown to be essential to assign functions to genes and to describe the dynamic molecular phenotype. Gas chromatography (GC) and liquid chromatography coupled to mass spectrometry (GC- and LC-MS) are well suited for the fast and comprehensive analysis of ultracomplex metabolite samples. For the integration of metabolite profiles with quantitative protein profiles, a high throughput (HTP) shotgun proteomics approach using LC-MS and label-free quantification of unique proteins in a complex protein digest is described. Multivariate statistics are applied to examine sample pattern recognition based on data-dimensionality reduction and biomarker identification in plant systems biology. The integration of the data reveal multiple correlative biomarkers providing evidence for an increase of information in such holistic approaches. With computational simulation of metabolic networks and experimental measurements, it can be shown that biochemical regulation is reflected by metabolite network dynamics measured in a metabolomics approach. Examples in molecular plant physiology are presented to substantiate the integrative approach.

  4. Effects of Single and Multifactor Treatments with Elevated Temperature, CO2 and Ozone on Oilseed Rape and Barley

    DEFF Research Database (Denmark)

    Clausen, Sabine Karin; Frenck, Georg; van der Linden, Leon Gareth

    2011-01-01

    We investigated the effect of elevated [CO2], [O3] and temperature on plant productivity and if these climate factors interacted with each other in multifactor treatments. The climate effects were studied in 14 different cultivars/lines of European spring oilseed rape (Brassica napus L.) and spring...... barley (Hordeum vulgare L.). Seven genotypes of each species were cultivated in six single- and multifactor treatments with ambient or elevated CO2 (385 ppm and 700 ppm), O3 (20 ppb and 60 ppb) and temperature (12/19 °C and 17/24 °C). Growth and production parameters were measured. Elevated CO2 increased....... A significantly decreased yield and thousand grain weight was also seen in barley due to elevated O3. The multifactor combination of elevated CO2, O3 and temperature showed a decrease in growth and production in the two species, though not statistically significant for all parameters. This trend suggests...

  5. MULTI-FACTOR ANALYSIS FOR SELECTING LUNAR EXPLORATION SOFT LANDING AREA AND THE BEST CRUISE ROUTE

    Directory of Open Access Journals (Sweden)

    N. Mou

    2018-04-01

    Full Text Available Selecting the right soft landing area and planning a reasonable cruise route are the basic tasks of lunar exploration. In this paper, the Von Karman crater in the Antarctic Aitken basin on the back of the moon is used as the study area, and multi-factor analysis is used to evaluate the landing area and cruise route of lunar exploration. The evaluation system mainly includes the factors such as the density of craters, the impact area of craters, the formation of the whole area and the formation of some areas, such as the vertical structure, rock properties and the content of (FeO + TiO2, which can reflect the significance of scientific exploration factor. And the evaluation of scientific exploration is carried out on the basis of safety and feasibility. On the basis of multi-factor superposition analysis, three landing zones A, B and C are selected, and the appropriate cruising route is analyzed through scientific research factors. This study provides a scientific basis for the lunar probe landing and cruise route planning, and it provides technical support for the subsequent lunar exploration.

  6. Multi-Factor Analysis for Selecting Lunar Exploration Soft Landing Area and the best Cruise Route

    Science.gov (United States)

    Mou, N.; Li, J.; Meng, Z.; Zhang, L.; Liu, W.

    2018-04-01

    Selecting the right soft landing area and planning a reasonable cruise route are the basic tasks of lunar exploration. In this paper, the Von Karman crater in the Antarctic Aitken basin on the back of the moon is used as the study area, and multi-factor analysis is used to evaluate the landing area and cruise route of lunar exploration. The evaluation system mainly includes the factors such as the density of craters, the impact area of craters, the formation of the whole area and the formation of some areas, such as the vertical structure, rock properties and the content of (FeO + TiO2), which can reflect the significance of scientific exploration factor. And the evaluation of scientific exploration is carried out on the basis of safety and feasibility. On the basis of multi-factor superposition analysis, three landing zones A, B and C are selected, and the appropriate cruising route is analyzed through scientific research factors. This study provides a scientific basis for the lunar probe landing and cruise route planning, and it provides technical support for the subsequent lunar exploration.

  7. Dimensionality reduction based on distance preservation to local mean for symmetric positive definite matrices and its application in brain-computer interfaces

    Science.gov (United States)

    Davoudi, Alireza; Shiry Ghidary, Saeed; Sadatnejad, Khadijeh

    2017-06-01

    Objective. In this paper, we propose a nonlinear dimensionality reduction algorithm for the manifold of symmetric positive definite (SPD) matrices that considers the geometry of SPD matrices and provides a low-dimensional representation of the manifold with high class discrimination in a supervised or unsupervised manner. Approach. The proposed algorithm tries to preserve the local structure of the data by preserving distances to local means (DPLM) and also provides an implicit projection matrix. DPLM is linear in terms of the number of training samples. Main results. We performed several experiments on the multi-class dataset IIa from BCI competition IV and two other datasets from BCI competition III including datasets IIIa and IVa. The results show that our approach as dimensionality reduction technique—leads to superior results in comparison with other competitors in the related literature because of its robustness against outliers and the way it preserves the local geometry of the data. Significance. The experiments confirm that the combination of DPLM with filter geodesic minimum distance to mean as the classifier leads to superior performance compared with the state of the art on brain-computer interface competition IV dataset IIa. Also the statistical analysis shows that our dimensionality reduction method performs significantly better than its competitors.

  8. Measurement Invariance of Second-Order Factor Model of the Multifactor Leadership Questionnaire (MLQ) across K-12 Principal Gender

    Science.gov (United States)

    Xu, Lihua; Wubbena, Zane; Stewart, Trae

    2016-01-01

    Purpose: The purpose of this paper is to investigate the factor structure and the measurement invariance of the Multifactor Leadership Questionnaire (MLQ) across gender of K-12 school principals (n=6,317) in the USA. Design/methodology/approach: Nine first-order factor models and four second-order factor models were tested using confirmatory…

  9. Dutch Multifactor Fatigue Scale : A New Scale to Measure the Different Aspects of Fatigue After Acquired Brain Injury

    NARCIS (Netherlands)

    Visser-Keizer, Annemarie C.; Hogenkamp, Antoinette; Westerhof-Evers, Herma J.; Egberink, Iris J. L.; Spikman, Jacoba M.

    Objectives: To develop the Dutch Multifactor Fatigue Scale (DMFS), a new scale to assess the nature and impact of fatigue and coping with fatigue in the chronic phase after acquired brain injury (ABI) and to analyze the psychometric properties of this scale in a mixed group of patients with ABI.

  10. Spectroscopically Enhanced Method and System for Multi-Factor Biometric Authentication

    Science.gov (United States)

    Pishva, Davar

    This paper proposes a spectroscopic method and system for preventing spoofing of biometric authentication. One of its focus is to enhance biometrics authentication with a spectroscopic method in a multifactor manner such that a person's unique ‘spectral signatures’ or ‘spectral factors’ are recorded and compared in addition to a non-spectroscopic biometric signature to reduce the likelihood of imposter getting authenticated. By using the ‘spectral factors’ extracted from reflectance spectra of real fingers and employing cluster analysis, it shows how the authentic fingerprint image presented by a real finger can be distinguished from an authentic fingerprint image embossed on an artificial finger, or molded on a fingertip cover worn by an imposter. This paper also shows how to augment two widely used biometrics systems (fingerprint and iris recognition devices) with spectral biometrics capabilities in a practical manner and without creating much overhead or inconveniencing their users.

  11. Multifactor investigation of relative postirradiation changes in various types of behavioural reactions in rats

    International Nuclear Information System (INIS)

    Davydov, B.I.; Tikhonchuk, V.S.; Karpov, V.N.; Ushakov, I.B.

    1989-01-01

    The use of the methods of multifactor, orthogonal and composition planning in studying the behavioural disturbances in rats after γ-irradiation with doses of 0.258 to 1.29 C/kg and the application of the proposed method of discrimination of effects by empirical models permitted to establish the informative and adequate dependences of the probability of these disturbances on dose of nonuniform irradiation and the degree of strengthening of the conditioned reflex. Within the range of the studied factors both the value of the dose of whole-body irradiation and the degree of strengthening of the conditioned reflex significantly affected the probability of fulfilling the task by the animals the significance of the radiation dose being several times higher. The effects of the interaction of the two factors, that is, irradiation and the radiation affection, were insignificant in changing the behavioural reactions under study

  12. Dimensional Reduction of N=1, E_8 SYM over SU(3)/U(1) x U(1) x Z_3 and its four-dimensional effective action

    CERN Document Server

    Irges, Nikos; Zoupanos, George

    2011-01-01

    We present an extension of the Standard Model inspired by the E_8 x E_8 Heterotic String. In order that a reasonable effective Lagrangian is presented we neglect everything else other than the ten-dimensional N=1 supersymmetric Yang-Mills sector associated with one of the gauge factors and certain couplings necessary for anomaly cancellation. We consider a compactified space-time M_4 x B_0 / Z_3, where B_0 is the nearly-Kaehler manifold SU(3)/U(1) x U(1) and Z_3 is a freely acting discrete group on B_0. Then we reduce dimensionally the E_8 on this manifold and we employ the Wilson flux mechanism leading in four dimensions to an SU(3)^3 gauge theory with the spectrum of a N=1 supersymmetric theory. We compute the effective four-dimensional Lagrangian and demonstrate that an extension of the Standard Model is obtained with interesting features including a conserved baryon number and fixed tree level Yukawa couplings and scalar potential. The spectrum contains new states such as right handed neutrinos and heavy ...

  13. Changes of platelet GMP-140 in diabetic nephropathy and its multi-factor regression analysis

    International Nuclear Information System (INIS)

    Wang Zizheng; Du Tongxin; Wang Shukui

    2001-01-01

    The relation of platelet GMP-140 and its related factors with diabetic nephropathy was studied. 144 patients of diabetic mellitus without nephropathy (group without DN, mean suffering duration of 25.5 +- 18.6 months); 80 with diabetic nephropathy (group DN, mean suffering duration of 58.7 +- 31.6 months) and 50 normal controls were chosen in the research. Platelet GMP-140, plasma α 1 -MG, β 2 -MG, and 24 hour urine albumin (ALB), IgG, α 1 -MG, β 2 -MG were detected by RIA, while HBA 1 C via chromatographic separation and FBG, PBG, Ch, TG, HDL, FG via biochemical methods. All the data had been processed with software on computer with t-test and linear regression, and multi-factor analysis were done also. The levels of platelet GMP-140, FG, DBP, TG, HBA 1 C and PBG in group DN were significantly higher than those of group without DN and normal control (P 0.05), while they were higher than those of normal controls. Multi-factor analysis of platelet GMP-140 with TG, DBP and HBA 1 C were performed in 80 patients with DN (P 1 C are the independent factors enhancing the activation of platelets. The disturbance of lipid metabolism in type II diabetic mellitus may also enhance the activation of platelets. Elevation of blood pressure may accelerate the initiation and deterioration of DN in which change of platelet GMP-140 is an independent factor. Elevation of HBA 1 C and blood glucose are related closely to the diabetic nephropathy

  14. Provincial carbon intensity abatement potential estimation in China: A PSO–GA-optimized multi-factor environmental learning curve method

    International Nuclear Information System (INIS)

    Yu, Shiwei; Zhang, Junjie; Zheng, Shuhong; Sun, Han

    2015-01-01

    This study aims to estimate carbon intensity abatement potential in China at the regional level by proposing a particle swarm optimization–genetic algorithm (PSO–GA) multivariate environmental learning curve estimation method. The model uses two independent variables, namely, per capita gross domestic product (GDP) and the proportion of the tertiary industry in GDP, to construct carbon intensity learning curves (CILCs), i.e., CO 2 emissions per unit of GDP, of 30 provinces in China. Instead of the traditional ordinary least squares (OLS) method, a PSO–GA intelligent optimization algorithm is used to optimize the coefficients of a learning curve. The carbon intensity abatement potentials of the 30 Chinese provinces are estimated via PSO–GA under the business-as-usual scenario. The estimation reveals the following results. (1) For most provinces, the abatement potentials from improving a unit of the proportion of the tertiary industry in GDP are higher than the potentials from raising a unit of per capita GDP. (2) The average potential of the 30 provinces in 2020 will be 37.6% based on the emission's level of 2005. The potentials of Jiangsu, Tianjin, Shandong, Beijing, and Heilongjiang are over 60%. Ningxia is the only province without intensity abatement potential. (3) The total carbon intensity in China weighted by the GDP shares of the 30 provinces will decline by 39.4% in 2020 compared with that in 2005. This intensity cannot achieve the 40%–45% carbon intensity reduction target set by the Chinese government. Additional mitigation policies should be developed to uncover the potentials of Ningxia and Inner Mongolia. In addition, the simulation accuracy of the CILCs optimized by PSO–GA is higher than that of the CILCs optimized by the traditional OLS method. - Highlights: • A PSO–GA-optimized multi-factor environmental learning curve method is proposed. • The carbon intensity abatement potentials of the 30 Chinese provinces are estimated by

  15. 'Marginal Employment' and the Demand for Heterogenous Labour: Empirical Evidence from a Multi-factor Labour Demand Model for Germany

    OpenAIRE

    Ronny Freier; Viktor Steiner

    2007-01-01

    We develop a structural multi-factor labour demand model which distinguishes between eight labour categories including non-standard types of employment such as marginal employment. The model is estimated for both the number of workers and total working hours using a new panel data set. For unskilled and skilled workers in full-time employment, we find labour demand elasticities similar to previous estimates for the west German economy. Our new estimates of own-wage elasticities for marginal e...

  16. Multifactor leadership styles and new exposure to workplace bullying: a six-month prospective study

    Science.gov (United States)

    TSUNO, Kanami; KAWAKAMI, Norito

    2014-01-01

    This study investigated the prospective association between supervisor leadership styles and workplace bullying. Altogether 404 civil servants from a local government in Japan completed baseline and follow-up surveys. The leadership variables and exposure to bullying were measured by Multifactor Leadership Questionnaire and Negative Acts Questionnaire-Revised, respectively. The prevalence of workplace bullying was 14.8% at baseline and 15.1% at follow-up. Among respondents who did not experience bullying at baseline (n=216), those who worked under the supervisors as higher in passive laissez-faire leadership had a 4.3 times higher risk of new exposure to bullying. On the other hand, respondents whose supervisors with highly considerate of the individual had a 70% lower risk of new exposure to bullying. In the entire sample (n=317), passive laissez-faire leadership was significantly and positively associated, while charisma/inspiration, individual consideration, and contingent reward were negatively associated both after adjusting for demographic and occupational characteristics at baseline, life events during follow-up, and exposure to workplace bullying at baseline. Results indicated that passive laissez-faire and low individual consideration leadership style at baseline were strong predictors of new exposure to bullying and high individual consideration leadership of supervisors/managers could be a preventive factor against bullying. PMID:25382384

  17. Multifactor Assessment of Metabolic Syndrome Risk in Uzbek Children and Adolescents with Obesity

    Directory of Open Access Journals (Sweden)

    Gulnara N. Rakhimova

    2016-03-01

    Full Text Available Metabolic syndrome (MetS contributes to early atherosclerotic changes of blood vessels and type 2 diabetes mellitusnot only among adults, but among children and adolescents, causing onset and progression of severe diseases resulting in early disablement and death. Multifactor analysis of MetS risk in Uzbek children and adolescents with exogenous-constitutional obesity (ECO was the purpose of the study. The study included 100 Uzbek children and adolescents with ECO aged from 6 to 16 (mean age 11.7±0.25 years—54(54.0% boys and 46(46.0% girls. Prognostic matrix was made up by means of a modification of Bayesian probability by E. Shigan (1986. Mathematical analysis confirmed a high degree of risk for MetS onset and progression in obese patients with disorders of lipid profile and hemodynamics. MetS risk is 8.2 times higher with levels of HDL-C 3.0, HbA1c >6.7%, and obesity onset before 5 years of age.

  18. Multifactor leadership styles and new exposure to workplace bullying: a six-month prospective study.

    Science.gov (United States)

    Tsuno, Kanami; Kawakami, Norito

    2015-01-01

    This study investigated the prospective association between supervisor leadership styles and workplace bullying. Altogether 404 civil servants from a local government in Japan completed baseline and follow-up surveys. The leadership variables and exposure to bullying were measured by Multifactor Leadership Questionnaire and Negative Acts Questionnaire-Revised, respectively. The prevalence of workplace bullying was 14.8% at baseline and 15.1% at follow-up. Among respondents who did not experience bullying at baseline (n=216), those who worked under the supervisors as higher in passive laissez-faire leadership had a 4.3 times higher risk of new exposure to bullying. On the other hand, respondents whose supervisors with highly considerate of the individual had a 70% lower risk of new exposure to bullying. In the entire sample (n=317), passive laissez-faire leadership was significantly and positively associated, while charisma/inspiration, individual consideration, and contingent reward were negatively associated both after adjusting for demographic and occupational characteristics at baseline, life events during follow-up, and exposure to workplace bullying at baseline. Results indicated that passive laissez-faire and low individual consideration leadership style at baseline were strong predictors of new exposure to bullying and high individual consideration leadership of supervisors/managers could be a preventive factor against bullying.

  19. Study of the X-Ray Diagnosis of Unstable Pelvic Fracture Displacements in Three-Dimensional Space and its Application in Closed Reduction.

    Science.gov (United States)

    Shi, Chengdi; Cai, Leyi; Hu, Wei; Sun, Junying

    2017-09-19

    ABSTRACTS Objective: To study the method of X-ray diagnosis of unstable pelvic fractures displaced in three-dimensional (3D) space and its clinical application in closed reduction. Five models of hemipelvic displacement were made in an adult pelvic specimen. Anteroposterior radiographs of the pelvis were analyzed in PACS. The method of X-ray diagnosis was applied in closed reductions. From February 2012 to June 2016, 23 patients (15 men, 8 women; mean age, 43.4 years) with unstable pelvic fractures were included. All patients were treated by closed reduction and percutaneous cannulate screw fixation of the pelvic ring. According to Tile's classification, the patients were classified into type B1 in 7 cases, B2 in 3, B3 in 3, C1 in 5, C2 in 3, and C3 in 2. The operation time and intraoperative blood loss were recorded. Postoperative images were evaluated by Matta radiographic standards. Five models of displacement were made successfully. The X-ray features of the models were analyzed. For clinical patients, the average operation time was 44.8 min (range, 20-90 min) and the average intraoperative blood loss was 35.7 (range, 20-100) mL. According to the Matta standards, 7 cases were excellent, 12 cases were good, and 4 were fair. The displacements in 3D space of unstable pelvic fractures can be diagnosed rapidly by X-ray analysis to guide closed reduction, with a satisfactory clinical outcome.

  20. One-dimensional reduction of the three-dimenstional Gross-Pitaevskii equation with two- and three-body interactions

    International Nuclear Information System (INIS)

    Cardoso, W. B.; Avelar, A. T.; Bazeia, D.

    2011-01-01

    We deal with the three-dimensional Gross-Pitaevskii equation which is used to describe a cloud of dilute bosonic atoms that interact under competing two- and three-body scattering potentials. We study the case where the cloud of atoms is strongly confined in two spatial dimensions, allowing us to build an unidimensional nonlinear equation,controlled by the nonlinearities and the confining potentials that trap the system along the longitudinal coordinate. We focus attention on specific limits dictated by the cubic and quintic coefficients, and we implement numerical simulations to help us to quantify the validity of the procedure.

  1. A Novel Sidelobe Reduction Algorithm Based on Two-Dimensional Sidelobe Correction Using D-SVA for Squint SAR Images

    Directory of Open Access Journals (Sweden)

    Min Liu

    2018-03-01

    Full Text Available Sidelobe reduction is a very primary task for synthetic aperture radar (SAR images. Various methods have been proposed for broadside SAR, which can suppress the sidelobes effectively while maintaining high image resolution at the same time. Alternatively, squint SAR, especially highly squint SAR, has emerged as an important tool that provides more mobility and flexibility and has become a focus of recent research studies. One of the research challenges for squint SAR is how to resolve the severe range-azimuth coupling of echo signals. Unlike broadside SAR images, the range and azimuth sidelobes of the squint SAR images no longer locate on the principal axes with high probability. Thus the spatially variant apodization (SVA filters could hardly get all the sidelobe information, and hence the sidelobe reduction process is not optimal. In this paper, we present an improved algorithm called double spatially variant apodization (D-SVA for better sidelobe suppression. Satisfactory sidelobe reduction results are achieved with the proposed algorithm by comparing the squint SAR images to the broadside SAR images. Simulation results also demonstrate the reliability and efficiency of the proposed method.

  2. A three-dimensional water quality modeling approach for exploring the eutrophication responses to load reduction scenarios in Lake Yilong (China)

    International Nuclear Information System (INIS)

    Zhao, Lei; Li, Yuzhao; Zou, Rui; He, Bin; Zhu, Xiang; Liu, Yong; Wang, Junsong; Zhu, Yongguan

    2013-01-01

    Lake Yilong in Southwestern China has been under serious eutrophication threat during the past decades; however, the lake water remained clear until sudden sharp increase in Chlorophyll a (Chl a) and turbidity in 2009 without apparent change in external loading levels. To investigate the causes as well as examining the underlying mechanism, a three-dimensional hydrodynamic and water quality model was developed, simulating the flow circulation, pollutant fate and transport, and the interactions between nutrients, phytoplankton and macrophytes. The calibrated and validated model was used to conduct three sets of scenarios for understanding the water quality responses to various load reduction intensities and ecological restoration measures. The results showed that (a) even if the nutrient loads is reduced by as much as 77%, the Chl a concentration decreased only by 50%; and (b) aquatic vegetation has strong interaction with phytoplankton, therefore requiring combined watershed and in-lake management for lake restoration. -- Highlights: ► We quantitatively investigated the non-linear lake responses to load reduction. ► The aquatic ecological condition had a great impact on algal blooms. ► Only water quality improvement cannot ensure the aquatic ecology restoration. -- The lake water quality responds to watershed load reduction in a nonlinear way, which requires combined watershed and in-lake management for lake restoration

  3. Bubble dynamic templated deposition of three-dimensional palladium nanostructure catalysts: Approach to oxygen reduction using macro-, micro-, and nano-architectures on electrode surfaces

    International Nuclear Information System (INIS)

    Yang Guimei; Chen Xing; Li Jie; Guo Zheng; Liu Jinhuai; Huang Xingjiu

    2011-01-01

    Highlights: → We synthesize the Pd nanostructures by bubbles dynamic templated. → We obtain Pd nanobuds and Pd nanodendrites by changing the reaction precursor. → We obtain Pd macroelectrode voltammertric behavior using small amount of Pd materials. → We proved a ECE process. → The Pd nanostructures/GCE for O 2 reduction is a 2-step 4-electron process. - Abstract: Three-dimensional (3D) palladium (Pd) nanostructures (that is, nano-buds or nano-dendrites) are fabricated by bubble dynamic templated deposition of Pd onto a glassy carbon electrode (GCE). The morphology can be tailored by changing the precursor concentration and reaction time. Scanning electron microscopy images reveal that nano-buds or nano-dendrites consist of nanoparticles of 40-70 nm in diameter. The electrochemical reduction of oxygen is reported at such kinds of 3D nanostructure electrodes in aqueous solution. Data were collected using cyclic voltammetry. We demonstrate the Pd macroelectrode behavior of Pd nanostructure modified electrode by exploiting the diffusion model of macro-, micro-, and nano-architectures. In contrast to bare GCE, a significant positive shift and splitting of the oxygen reduction peak (vs Ag/AgCl/saturated KCl) at Pd nanostructure modified GCE was observed.

  4. Multi-factor challenge/response approach for remote biometric authentication

    Science.gov (United States)

    Al-Assam, Hisham; Jassim, Sabah A.

    2011-06-01

    Although biometric authentication is perceived to be more reliable than traditional authentication schemes, it becomes vulnerable to many attacks when it comes to remote authentication over open networks and raises serious privacy concerns. This paper proposes a biometric-based challenge-response approach to be used for remote authentication between two parties A and B over open networks. In the proposed approach, a remote authenticator system B (e.g. a bank) challenges its client A who wants to authenticate his/her self to the system by sending a one-time public random challenge. The client A responds by employing the random challenge along with secret information obtained from a password and a token to produce a one-time cancellable representation of his freshly captured biometric sample. The one-time biometric representation, which is based on multi-factor, is then sent back to B for matching. Here, we argue that eavesdropping of the one-time random challenge and/or the resulting one-time biometric representation does not compromise the security of the system, and no information about the original biometric data is leaked. In addition to securing biometric templates, the proposed protocol offers a practical solution for the replay attack on biometric systems. Moreover, we propose a new scheme for generating a password-based pseudo random numbers/permutation to be used as a building block in the proposed approach. The proposed scheme is also designed to provide protection against repudiation. We illustrate the viability and effectiveness of the proposed approach by experimental results based on two biometric modalities: fingerprint and face biometrics.

  5. A polyacrylonitrile copolymer-silica template for three-dimensional hierarchical porous carbon as a Pt catalyst support for the oxygen reduction reaction.

    Science.gov (United States)

    Liu, Minmin; Li, Jian; Cai, Chao; Zhou, Ziwei; Ling, Yun; Liu, Rui

    2017-08-01

    Herein, we report a novel route to construct a hierarchical three-dimensional porous carbon (3DC) through a copolymer-silica assembly. In the synthesis, silica acts as a hard template and leads to the formation of an interconnected 3D macropore, whereas styrene-co-acrylonitrile polymer has been used as both a carbon source and a soft template for micro- and meso-pores. The obtained 3DC materials possess a large surface area (∼550.5 m 2 g -1 ), which facilitates high dispersion of Pt nanoparticles on the carbon support. The 3DC-supported Pt electrocatalyst shows excellent performance in the oxygen reduction reaction (ORR). The easy processing ability along with the characteristics of hierarchical porosity offers a new strategy for the preparation of carbon nanomaterials for energy application.

  6. Bioconductor workflow for single-cell RNA sequencing: Normalization, dimensionality reduction, clustering, and lineage inference [version 1; referees: 1 approved, 2 approved with reservations

    Directory of Open Access Journals (Sweden)

    Fanny Perraudeau

    2017-07-01

    Full Text Available Novel single-cell transcriptome sequencing assays allow researchers to measure gene expression levels at the resolution of single cells and offer the unprecendented opportunity to investigate at the molecular level fundamental biological questions, such as stem cell differentiation or the discovery and characterization of rare cell types. However, such assays raise challenging statistical and computational questions and require the development of novel methodology and software. Using stem cell differentiation in the mouse olfactory epithelium as a case study, this integrated workflow provides a step-by-step tutorial to the methodology and associated software for the following four main tasks: (1 dimensionality reduction accounting for zero inflation and over dispersion and adjusting for gene and cell-level covariates; (2 cell clustering using resampling-based sequential ensemble clustering; (3 inference of cell lineages and pseudotimes; and (4 differential expression analysis along lineages.

  7. Evaluation of Orthopedic Metal Artifact Reduction Application in Three-Dimensional Computed Tomography Reconstruction of Spinal Instrumentation: A Single Saudi Center Experience.

    Science.gov (United States)

    Ali, Amir Monir

    2018-01-01

    The aim of the study was to evaluate the commercially available orthopedic metal artifact reduction (OMAR) technique in postoperative three-dimensional computed tomography (3DCT) reconstruction studies after spinal instrumentation and to investigate its clinical application. One hundred and twenty (120) patients with spinal metallic implants were included in the study. All had 3DCT reconstruction examinations using the OMAR software after obtaining the informed consents and approval of the Institution Ethical Committee. The degree of the artifacts, the related muscular density, the clearness of intermuscular fat planes, and definition of the adjacent vertebrae were qualitatively evaluated. The diagnostic satisfaction and quality of the 3D reconstruction images were thoroughly assessed. The majority (96.7%) of 3DCT reconstruction images performed were considered satisfactory to excellent for diagnosis. Only 3.3% of the reconstructed images had rendered unacceptable diagnostic quality. OMAR can effectively reduce metallic artifacts in patients with spinal instrumentation with highly diagnostic 3DCT reconstruction images.

  8. Challenging terrestrial biosphere models with data from the long-term multifactor Prairie Heating and CO2 Enrichment experiment.

    Science.gov (United States)

    De Kauwe, Martin G; Medlyn, Belinda E; Walker, Anthony P; Zaehle, Sönke; Asao, Shinichi; Guenet, Bertrand; Harper, Anna B; Hickler, Thomas; Jain, Atul K; Luo, Yiqi; Lu, Xingjie; Luus, Kristina; Parton, William J; Shu, Shijie; Wang, Ying-Ping; Werner, Christian; Xia, Jianyang; Pendall, Elise; Morgan, Jack A; Ryan, Edmund M; Carrillo, Yolima; Dijkstra, Feike A; Zelikova, Tamara J; Norby, Richard J

    2017-09-01

    Multifactor experiments are often advocated as important for advancing terrestrial biosphere models (TBMs), yet to date, such models have only been tested against single-factor experiments. We applied 10 TBMs to the multifactor Prairie Heating and CO 2 Enrichment (PHACE) experiment in Wyoming, USA. Our goals were to investigate how multifactor experiments can be used to constrain models and to identify a road map for model improvement. We found models performed poorly in ambient conditions; there was a wide spread in simulated above-ground net primary productivity (range: 31-390 g C m -2  yr -1 ). Comparison with data highlighted model failures particularly with respect to carbon allocation, phenology, and the impact of water stress on phenology. Performance against the observations from single-factors treatments was also relatively poor. In addition, similar responses were predicted for different reasons across models: there were large differences among models in sensitivity to water stress and, among the N cycle models, N availability during the experiment. Models were also unable to capture observed treatment effects on phenology: they overestimated the effect of warming on leaf onset and did not allow CO 2 -induced water savings to extend the growing season length. Observed interactive (CO 2  × warming) treatment effects were subtle and contingent on water stress, phenology, and species composition. As the models did not correctly represent these processes under ambient and single-factor conditions, little extra information was gained by comparing model predictions against interactive responses. We outline a series of key areas in which this and future experiments could be used to improve model predictions of grassland responses to global change. © 2017 John Wiley & Sons Ltd.

  9. Tailored Combination of Low Dimensional Catalysts for Efficient Oxygen Reduction and Evolution in Li-O2 Batteries.

    Science.gov (United States)

    Yoon, Ki Ro; Kim, Dae Sik; Ryu, Won-Hee; Song, Sung Ho; Youn, Doo-Young; Jung, Ji-Won; Jeon, Seokwoo; Park, Yong Joon; Kim, Il-Doo

    2016-08-23

    The development of efficient bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a key issue pertaining high performance Li-O2 batteries. Here, we propose a heterogeneous electrocatalyst consisting of LaMnO3 nanofibers (NFs) functionalized with RuO2 nanoparticles (NPs) and non-oxidized graphene nanoflakes (GNFs). The Li-O2 cell employing the tailored catalysts delivers an excellent electrochemical performance, affording significantly reduced discharge/charge voltage gaps (1.0 V at 400 mA g(-1) ), and superior cyclability for over 320 cycles. The outstanding performance arises from (1) the networked LaMnO3 NFs providing ORR/OER sites without severe aggregation, (2) the synergistic coupling of RuO2 NPs for further improving the OER activity and the electrical conductivity on the surface of the LaMnO3 NFs, and (3) the use of GNFs providing a fast electronic pathway as well as improved ORR kinetics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Facile preparation of three-dimensional Co1-xS/sulfur and nitrogen-codoped graphene/carbon foam for highly efficient oxygen reduction reaction

    Science.gov (United States)

    Liang, Hui; Li, Chenwei; Chen, Tao; Cui, Liang; Han, Jingrui; Peng, Zhi; Liu, Jingquan

    2018-02-01

    Because of the urgent need for renewable resources, oxygen reduction reaction (ORR) has been widely studied. Finding efficient and low cost non-precious metal catalyst is increasingly critical. In this study, melamine foam is used as template to obtain porous sulfur and nitrogen-codoped graphene/carbon foam with uniformly distributed cobalt sulfide nanoparticles (Co1-xS/SNG/CF) which is prepared by a simple infiltration-drying-sulfuration method. It is noteworthy that melamine foam not only works as a three-dimensional support skeleton, but also provides a nitrogen source without any environmental pollution. Such Co1-xS/SNG/CF catalyst shows excellent oxygen reduction catalytic performance with an onset potential of only 0.99 V, which is the same as that of Pt/C catalyst (Eonset = 0.99 V). Furthermore, the stability and methanol tolerance of Co1-xS/SNG/CF are more outstanding than those of Pt/C catalyst. Our work manifests a facile method to prepare S and N-codoped 3D graphene network decorated with Co1-xS nanoparticles, which may be utilized as potential alternative to the expensive Pt/C catalysts toward ORR.

  11. Facile Synthesis of Quasi-One-Dimensional Au/PtAu Heterojunction Nanotubes and Their Application as Catalysts in an Oxygen-Reduction Reaction.

    Science.gov (United States)

    Cai, Kai; Liu, Jiawei; Zhang, Huan; Huang, Zhao; Lu, Zhicheng; Foda, Mohamed F; Li, Tingting; Han, Heyou

    2015-05-11

    An intermediate-template-directed method has been developed for the synthesis of quasi-one-dimensional Au/PtAu heterojunction nanotubes by the heterogeneous nucleation and growth of Au on Te/Pt core-shell nanostructures in aqueous solution. The synthesized porous Au/PtAu bimetallic nanotubes (PABNTs) consist of porous tubular framework and attached Au nanoparticles (AuNPs). The reaction intermediates played an important role in the preparation, which fabricated the framework and provided a localized reducing agent for the reduction of the Au and Pt precursors. The Pt7 Au PABNTs showed higher electrocatalytic activity and durability in the oxygen-reduction reaction (ORR) in 0.1 M HClO4 than porous Pt nanotubes (PtNTs) and commercially available Pt/C. The mass activity of PABNTs was 218 % that of commercial Pt/C after an accelerated durability test. This study demonstrates the potential of PABNTs as highly efficient electrocatalysts. In addition, this method provides a facile strategy for the synthesis of desirable hetero-nanostructures with controlled size and shape by utilizing an intermediate template. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Controllable one-pot synthesis of various one-dimensional Bi2S3 nanostructures and their enhanced visible-light-driven photocatalytic reduction of Cr(VI)

    International Nuclear Information System (INIS)

    Hu, Enlai; Gao, Xuehui; Etogo, Atangana; Xie, Yunlong; Zhong, Yijun; Hu, Yong

    2014-01-01

    Highlights: • 1D Bi 2 S 3 nanostructures were prepared by a facile ethanol-assisted one-pot reaction. • The size and morphology of the products can be conveniently varied. • The sulfur source plays a crucial role in determining the morphologies of products. • 1D Bi 2 S 3 nanostructures exhibit enhanced photocatalytic reduction of Cr(VI). • Bi 2 S 3 nanowires exhibit the highest photoreduction activity among three samples. - Abstract: One-dimensional (1D) Bi 2 S 3 nanostructures with various morphologies, including nanowires, nanorods, and nanotubes, have been successfully synthesized through a facile ethanol-assisted one-pot reaction. It is found that the size, morphology and structure of the products can be conveniently varied or controlled by simply adjusting the volume ratio of ethanol and water in the reaction system. Further experimental results indicate that sulfur source also plays the other crucial role in determining the product morphology. The synthetic strategy developed in this work is highly efficient in producing 1D Bi 2 S 3 nanostructures with high quality and large quantity. Photocatalysis experiments show the as-prepared 1D Bi 2 S 3 nanostructures possess significantly enhanced photocatalytic reduction of Cr(VI) when exposed to visible light irradiation. Especially, Bi 2 S 3 nanowires exhibit the highest photocatalytic activity and can be used repeatedly after washed with dilute HCl

  13. Facile fabrication of three-dimensional mesoporous Si/SiC composites via one-step magnesiothermic reduction at relative low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Zhihang; Ma, Yongjun [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Zhou, Yong [Eco-materials and Renewable Energy Research Center (ERERC), School of Physics, National Lab of Solid State Microstructure, ERERC, Nanjing University, Nanjing 210093 (China); Hu, Shanglian [School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Han, Chaojiang [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Pei, Chonghua, E-mail: peichonghua@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China)

    2013-10-15

    Graphical abstract: - Highlights: • The Si/SiC composites were synthesized by one-step magnesiothermic reduction. • The mesoporous composites have a high specific surface area (655.7 m{sup 2} g{sup −1}). • The composites exhibited a strong photoluminescence and better biocompatibility. • The mechanisms of formation and photoluminescence of sample were discussed. - Abstract: By converting modified silica aerogels to the corresponding silicon/silicon carbide (Si/SiC) without losing its nanostructure, three-dimensional mesoporous (3DM) Si/SiC composites are successfully synthesized via one-step magnesothermic reduction at relative low temperature (650 °C). The phase composition and microstructure of the resulting samples are measured by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectra, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). N{sub 2}-sorption isotherms results show that the products have high Brunauer–Emmett–Teller (BET) specific surface areas (up to 656 m{sup 2} g{sup −1}) and narrow pore-size distributions (1.5–30 nm). The composites exhibit a strong photoluminescence (PL) in blue-green light region (peak centered at 533 nm). We have set out work on the biocompatibility and enhancing PL of samples. As a result of excellent performances of the composites, it can be expected to have significant application in optoelectronics, biosensors, biological tracer and so on.

  14. Posterior Reduction and Monosegmental Fusion with Intraoperative Three-dimensional Navigation System in the Treatment of High-grade Developmental Spondylolisthesis

    Directory of Open Access Journals (Sweden)

    Wei Tian

    2015-01-01

    Full Text Available Background: The treatment of high-grade developmental spondylolisthesis (HGDS is still challenging and controversial. In this study, we investigated the efficacy of the posterior reduction and monosegmental fusion assisted by intraoperative three-dimensional (3D navigation system in managing the HGDS. Methods: Thirteen consecutive HGDS patients were treated with posterior decompression, reduction and monosegmental fusion of L5/S1, assisted by intraoperative 3D navigation system. The clinical and radiographic outcomes were evaluated, with a minimum follow-up of 2 years. The differences between the pre- and post-operative measures were statistically analyzed using a two-tailed, paired t-test. Results: At most recent follow-up, 12 patients were pain-free. Only 1 patient had moderate pain. There were no permanent neurological complications or pseudarthrosis. The magnetic resonance imaging showed that there was no obvious disc degeneration in the adjacent segment. All radiographic parameters were improved. Mean slippage improved from 63.2% before surgery to 12.2% after surgery and 11.0% at latest follow-up. Lumbar lordosis changed from preoperative 34.9 ± 13.3° to postoperative 50.4 ± 9.9°, and 49.3 ± 7.8° at last follow-up. L5 incidence improved from 71.0 ± 11.3° to 54.0 ± 11.9° and did not change significantly at the last follow-up 53.1 ± 15.4°. While pelvic incidence remained unchanged, sacral slip significantly decreased from preoperative 32.7 ± 12.5° to postoperative 42.6 ± 9.8°and remained constant to the last follow-up 44.4 ± 6.9°. Pelvic tilt significantly decreased from 38.4 ± 12.5° to 30.9 ± 8.1° and remained unchanged at the last follow-up 28.1 ± 11.2°. Conclusions: Posterior reduction and monosegmental fusion of L5/S1 assisted by intraoperative 3D navigation are an effective technique for managing high-grade dysplastic spondylolisthesis. A complete reduction of local deformity and excellent correction of overall

  15. Survival dimensionality reduction (SDR: development and clinical application of an innovative approach to detect epistasis in presence of right-censored data

    Directory of Open Access Journals (Sweden)

    Beretta Lorenzo

    2010-08-01

    Full Text Available Abstract Background Epistasis is recognized as a fundamental part of the genetic architecture of individuals. Several computational approaches have been developed to model gene-gene interactions in case-control studies, however, none of them is suitable for time-dependent analysis. Herein we introduce the Survival Dimensionality Reduction (SDR algorithm, a non-parametric method specifically designed to detect epistasis in lifetime datasets. Results The algorithm requires neither specification about the underlying survival distribution nor about the underlying interaction model and proved satisfactorily powerful to detect a set of causative genes in synthetic epistatic lifetime datasets with a limited number of samples and high degree of right-censorship (up to 70%. The SDR method was then applied to a series of 386 Dutch patients with active rheumatoid arthritis that were treated with anti-TNF biological agents. Among a set of 39 candidate genes, none of which showed a detectable marginal effect on anti-TNF responses, the SDR algorithm did find that the rs1801274 SNP in the FcγRIIa gene and the rs10954213 SNP in the IRF5 gene non-linearly interact to predict clinical remission after anti-TNF biologicals. Conclusions Simulation studies and application in a real-world setting support the capability of the SDR algorithm to model epistatic interactions in candidate-genes studies in presence of right-censored data. Availability: http://sourceforge.net/projects/sdrproject/

  16. Reduction of respiratory ghosting motion artifacts in conventional two-dimensional multi-slice Cartesian turbo spin-echo: which k-space filling order is the best?

    Science.gov (United States)

    Inoue, Yuuji; Yoneyama, Masami; Nakamura, Masanobu; Takemura, Atsushi

    2018-06-01

    The two-dimensional Cartesian turbo spin-echo (TSE) sequence is widely used in routine clinical studies, but it is sensitive to respiratory motion. We investigated the k-space orders in Cartesian TSE that can effectively reduce motion artifacts. The purpose of this study was to demonstrate the relationship between k-space order and degree of motion artifacts using a moving phantom. We compared the degree of motion artifacts between linear and asymmetric k-space orders. The actual spacing of ghost artifacts in the asymmetric order was doubled compared with that in the linear order in the free-breathing situation. The asymmetric order clearly showed less sensitivity to incomplete breath-hold at the latter half of the imaging period. Because of the actual number of partitions of the k-space and the temporal filling order, the asymmetric k-space order of Cartesian TSE was superior to the linear k-space order for reduction of ghosting motion artifacts.

  17. Multi-factor analysis on events related to hematological toxicity in 153Sm-EDTMP palliative therapy for skeletal metastases

    International Nuclear Information System (INIS)

    Zhan Hongwei; Yu Xiaoling; Ye Xiaojuan; Bao Chengkan; Sun Da; He Gangqiang

    2006-01-01

    Objective: To investigate the clinical factors related to hematological toxicity induced by intravenous samarium-153 ethylenediaminetetramethylene phosphonic acid ( 153 Sm-EDTMP) treatment. Methods A total of 206 patients with bony metastases treated with 153 Sm-EDTMP were retrospectively analyzed. Logistic regression (SPSS 10.0 for Windows) and correlation analysis were used to evaluate the factors concerned. Results: Age of the patient, number of bone metastatic lesion, chemotherapy before 153 Sm-EDTMP therapy, concurrent radiotherapy and repeat-times of 153 Sm-EDTMP treatments were found the individual factors related to hematological toxicity. Chemotherapy before 153 Sm-EDTMP, concurrent radiotherapy, medication for normal blood counting and repeat-times of 153 Sm-EDTMP treatments were the hematological toxicity factors in multi-factor analysis. Conclusion: In 153 Sm-EDTMP therapy, several factors were found related to hematological toxicity suggesting more attention be paid to the change of blood cell counting after the palliative therapy. (authors)

  18. Template-free synthesis of three-dimensional nanoporous N-doped graphene for high performance fuel cell oxygen reduction reaction in alkaline media

    International Nuclear Information System (INIS)

    Tang, Sheng; Zhou, Xuejun; Xu, Nengneng; Bai, Zhengyu; Qiao, Jinli; Zhang, Jiujun

    2016-01-01

    Highlights: • 3-D porous N-doped graphene was prepared using one-step silica template-free method. • High specific surface area of 920 m 2 g −1 was achieved for 3-D porous N-doped graphene. • Much higher ORR activity was observed for N-doped graphene than S-doped one in 0.1 M KOH. • The as-prepared catalyst gave a peak power density of 275 mW cm −2 as zinc–air battery cathode. - Abstract: Three-dimensional nanoporous nitrogen-doped graphene (3D-PNG) has been synthesized through a facial one-step synthesis method without additional silica template. The as-prepared 3D-PNGwas used as an electrocatalyst for the oxygen reduction reaction (ORR), which shows excellent electrochemistry performance, demonstrated by half-cell electrochemical evaluation in 0.1 M KOH including prominent ORR activity, four electron-selectivity and remarkable methanol poisoning stability compared to commercial 20%Pt/C catalyst. The physical and surface properties of 3D-PNG catalyst were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and BET surface area analysis. The experiments show that 3D-PNG catalyst possesses super-large specific surface area reaching 920 m 2 g −1 , which is superior to our most recently reported 3D-PNG synthesized by silica template (670 m 2 g −1 ) and other doped graphene catalysts in literature. When used for constructing a zinc–air battery cathode, such an 3D-PNG catalyst can give a discharge peak power density of 275 mW cm −2 . All the results announce a unique procedure to product high-efficiency graphene-based non-noble metal catalyst materials for electrochemical energy devices including both fuel cells and metal–air batteries.

  19. An Out-of-Core GPU based dimensionality reduction algorithm for Big Mass Spectrometry Data and its application in bottom-up Proteomics.

    Science.gov (United States)

    Awan, Muaaz Gul; Saeed, Fahad

    2017-08-01

    Modern high resolution Mass Spectrometry instruments can generate millions of spectra in a single systems biology experiment. Each spectrum consists of thousands of peaks but only a small number of peaks actively contribute to deduction of peptides. Therefore, pre-processing of MS data to detect noisy and non-useful peaks are an active area of research. Most of the sequential noise reducing algorithms are impractical to use as a pre-processing step due to high time-complexity. In this paper, we present a GPU based dimensionality-reduction algorithm, called G-MSR, for MS2 spectra. Our proposed algorithm uses novel data structures which optimize the memory and computational operations inside GPU. These novel data structures include Binary Spectra and Quantized Indexed Spectra (QIS) . The former helps in communicating essential information between CPU and GPU using minimum amount of data while latter enables us to store and process complex 3-D data structure into a 1-D array structure while maintaining the integrity of MS data. Our proposed algorithm also takes into account the limited memory of GPUs and switches between in-core and out-of-core modes based upon the size of input data. G-MSR achieves a peak speed-up of 386x over its sequential counterpart and is shown to process over a million spectra in just 32 seconds. The code for this algorithm is available as a GPL open-source at GitHub at the following link: https://github.com/pcdslab/G-MSR.

  20. Image Quality and Radiation Dose of CT Coronary Angiography with Automatic Tube Current Modulation and Strong Adaptive Iterative Dose Reduction Three-Dimensional (AIDR3D.

    Directory of Open Access Journals (Sweden)

    Hesong Shen

    Full Text Available To investigate image quality and radiation dose of CT coronary angiography (CTCA scanned using automatic tube current modulation (ATCM and reconstructed by strong adaptive iterative dose reduction three-dimensional (AIDR3D.Eighty-four consecutive CTCA patients were collected for the study. All patients were scanned using ATCM and reconstructed with strong AIDR3D, standard AIDR3D and filtered back-projection (FBP respectively. Two radiologists who were blinded to the patients' clinical data and reconstruction methods evaluated image quality. Quantitative image quality evaluation included image noise, signal-to-noise ratio (SNR, and contrast-to-noise ratio (CNR. To evaluate image quality qualitatively, coronary artery is classified into 15 segments based on the modified guidelines of the American Heart Association. Qualitative image quality was evaluated using a 4-point scale. Radiation dose was calculated based on dose-length product.Compared with standard AIDR3D, strong AIDR3D had lower image noise, higher SNR and CNR, their differences were all statistically significant (P<0.05; compared with FBP, strong AIDR3D decreased image noise by 46.1%, increased SNR by 84.7%, and improved CNR by 82.2%, their differences were all statistically significant (P<0.05 or 0.001. Segments with diagnostic image quality for strong AIDR3D were 336 (100.0%, 486 (96.4%, and 394 (93.8% in proximal, middle, and distal part respectively; whereas those for standard AIDR3D were 332 (98.8%, 472 (93.7%, 378 (90.0%, respectively; those for FBP were 217 (64.6%, 173 (34.3%, 114 (27.1%, respectively; total segments with diagnostic image quality in strong AIDR3D (1216, 96.5% were higher than those of standard AIDR3D (1182, 93.8% and FBP (504, 40.0%; the differences between strong AIDR3D and standard AIDR3D, strong AIDR3D and FBP were all statistically significant (P<0.05 or 0.001. The mean effective radiation dose was (2.55±1.21 mSv.Compared with standard AIDR3D and FBP, CTCA

  1. Potential barriers to the application of multi-factor portfolio analysis in public hospitals: evidence from a pilot study in the Netherlands.

    Science.gov (United States)

    Pavlova, Milena; Tsiachristas, Apostolos; Vermaeten, Gerhard; Groot, Wim

    2009-01-01

    Portfolio analysis is a business management tool that can assist health care managers to develop new organizational strategies. The application of portfolio analysis to US hospital settings has been frequently reported. In Europe however, the application of this technique has received little attention, especially concerning public hospitals. Therefore, this paper examines the peculiarities of portfolio analysis and its applicability to the strategic management of European public hospitals. The analysis is based on a pilot application of a multi-factor portfolio analysis in a Dutch university hospital. The nature of portfolio analysis and the steps in a multi-factor portfolio analysis are reviewed along with the characteristics of the research setting. Based on these data, a multi-factor portfolio model is developed and operationalized. The portfolio model is applied in a pilot investigation to analyze the market attractiveness and hospital strengths with regard to the provision of three orthopedic services: knee surgery, hip surgery, and arthroscopy. The pilot portfolio analysis is discussed to draw conclusions about potential barriers to the overall adoption of portfolio analysis in the management of a public hospital. Copyright (c) 2008 John Wiley & Sons, Ltd.

  2. Multi-factor evaluation indicator method for the risk assessment of atmospheric and oceanic hazard group due to the attack of tropical cyclones

    Science.gov (United States)

    Qi, Peng; Du, Mei

    2018-06-01

    China's southeast coastal areas frequently suffer from storm surge due to the attack of tropical cyclones (TCs) every year. Hazards induced by TCs are complex, such as strong wind, huge waves, storm surge, heavy rain, floods, and so on. The atmospheric and oceanic hazards cause serious disasters and substantial economic losses. This paper, from the perspective of hazard group, sets up a multi-factor evaluation method for the risk assessment of TC hazards using historical extreme data of concerned atmospheric and oceanic elements. Based on the natural hazard dynamic process, the multi-factor indicator system is composed of nine natural hazard factors representing intensity and frequency, respectively. Contributing to the indicator system, in order of importance, are maximum wind speed by TCs, attack frequency of TCs, maximum surge height, maximum wave height, frequency of gusts ≥ Scale 8, rainstorm intensity, maximum tidal range, rainstorm frequency, then sea-level rising rate. The first four factors are the most important, whose weights exceed 10% in the indicator system. With normalization processing, all the single-hazard factors are superposed by multiplying their weights to generate a superposed TC hazard. The multi-factor evaluation indicator method was applied to the risk assessment of typhoon-induced atmospheric and oceanic hazard group in typhoon-prone southeast coastal cities of China.

  3. A computational intelligent approach to multi-factor analysis of violent crime information system

    Science.gov (United States)

    Liu, Hongbo; Yang, Chao; Zhang, Meng; McLoone, Seán; Sun, Yeqing

    2017-02-01

    Various scientific studies have explored the causes of violent behaviour from different perspectives, with psychological tests, in particular, applied to the analysis of crime factors. The relationship between bi-factors has also been extensively studied including the link between age and crime. In reality, many factors interact to contribute to criminal behaviour and as such there is a need to have a greater level of insight into its complex nature. In this article we analyse violent crime information systems containing data on psychological, environmental and genetic factors. Our approach combines elements of rough set theory with fuzzy logic and particle swarm optimisation to yield an algorithm and methodology that can effectively extract multi-knowledge from information systems. The experimental results show that our approach outperforms alternative genetic algorithm and dynamic reduct-based techniques for reduct identification and has the added advantage of identifying multiple reducts and hence multi-knowledge (rules). Identified rules are consistent with classical statistical analysis of violent crime data and also reveal new insights into the interaction between several factors. As such, the results are helpful in improving our understanding of the factors contributing to violent crime and in highlighting the existence of hidden and intangible relationships between crime factors.

  4. The visualization and analysis of urban facility pois using network kernel density estimation constrained by multi-factors

    Directory of Open Access Journals (Sweden)

    Wenhao Yu

    Full Text Available The urban facility, one of the most important service providers is usually represented by sets of points in GIS applications using POI (Point of Interest model associated with certain human social activities. The knowledge about distribution intensity and pattern of facility POIs is of great significance in spatial analysis, including urban planning, business location choosing and social recommendations. Kernel Density Estimation (KDE, an efficient spatial statistics tool for facilitating the processes above, plays an important role in spatial density evaluation, because KDE method considers the decay impact of services and allows the enrichment of the information from a very simple input scatter plot to a smooth output density surface. However, the traditional KDE is mainly based on the Euclidean distance, ignoring the fact that in urban street network the service function of POI is carried out over a network-constrained structure, rather than in a Euclidean continuous space. Aiming at this question, this study proposes a computational method of KDE on a network and adopts a new visualization method by using 3-D "wall" surface. Some real conditional factors are also taken into account in this study, such as traffic capacity, road direction and facility difference. In practical works the proposed method is implemented in real POI data in Shenzhen city, China to depict the distribution characteristic of services under impacts of multi-factors.

  5. Decline in the deepwater benthic communities abundance in the Onego Lake under multifactor influence

    Directory of Open Access Journals (Sweden)

    Kalinkina Nataliya Michailovna

    2016-06-01

    Full Text Available The dynamics of deepwater benthic communities state between 1988 and 2015 was analyzed. In the last decade the decline in the deepwater benthic communities development indicators is observed in Petrozavodskaya Bay and contiguous central area of the Lake Onego. The abundance of benthos decreased by 6-7 times, biomass dropped in 2-4 times. At the same time the changes in sedimentation processes of organic matter, nutrients, iron and manganese are observed in the water ecosystem. This has resulted in an increase in the concentrations of Fe and Mn in the sediment surface layers; in pore waters up to 13 mg Fe/l and 7 mg Mn/l. The sharp increase in the content of iron and manganese in the bottom sediment can be considered as a possible factor of benthos oppression. Another reason of the benthos decrease is the reduction of anthropogenic load. Now Petrozavodskaya bay receives 3 times less light organic substances than 10 years ago. The third possible reason for the reduction of benthic communities is invasion of baikalian amphipods Gmelinoides fasciatus, resulting in the redistribution of organic matter flow from the littoral zone to the pelagic zone and depletion of deepwater benthic food resources.

  6. Cloud Computing Integrated Multi-Factor Authentication Framework Application in Logistics Information Systems

    Directory of Open Access Journals (Sweden)

    Zeynel Erdi Karabulut

    2017-12-01

    Full Text Available As new technology enables firms to perform many daily processes easier the need of authentication and authorization process is becoming an integral part of many businesses. Also mobile applications are very popular nowadays play an important role in our lives. Such demands are not only limited to Logistics Information Systems (LIS but many field of information system as well. In this study multi-dimensional authentication which consist of online biometric face detection integrated as cloud computing software as a Service (SaaS, Near Field Communication (NFC card authentication, location confirmation, and temporal data confirmation are gathered together to fulfill different scenarios of authentication needs of business. Microsoft Face API (Application Program Interface, SAAS (software as a service has been used in face recognition module of developed mobile application. The face recognition module of the mobile application has been tested with Yale Face Database. Location, temporal data and NFC card information are collected and confirmed by the mobile application for authentication and authorization. These images were tested with our facial recognition module and confusion matrices were created. The accuracy of the system after the facial recognition test was found to be 100%. NFC card, location and temporal data authentication not only further increases security level but also fulfils many business authentication scenarios successfully. To the best of our knowledge there is no other authentication model other than implemented one that has a-4-factor confirmation including biometric face identification, NFC card authentication, location confirmation and temporal data confirmation.

  7. Tumor Volume Changes Assessed by Three-Dimensional Magnetic Resonance Volumetry in Rectal Cancer Patients After Preoperative Chemoradiation: The Impact of the Volume Reduction Ratio on the Prediction of Pathologic Complete Response

    International Nuclear Information System (INIS)

    Kang, Jeong Hyun; Kim, Young Chul; Kim, Hyunki; Kim, Young Wan; Hur, Hyuk; Kim, Jin Soo; Min, Byung Soh; Kim, Hogeun; Lim, Joon Seok; Seong, Jinsil; Keum, Ki Chang; Kim, Nam Kyu

    2010-01-01

    Purpose: The aim of this study was to determine the correlation between tumor volume changes assessed by three-dimensional (3D) magnetic resonance (MR) volumetry and the histopathologic tumor response in rectal cancer patients undergoing preoperative chemoradiation therapy (CRT). Methods and Materials: A total of 84 patients who underwent preoperative CRT followed by radical surgery were prospectively enrolled in the study. The post-treatment tumor volume and tumor volume reduction ratio (% decrease ratio), as shown by 3D MR volumetry, were compared with the histopathologic response, as shown by T and N downstaging and the tumor regression grade (TRG). Results: There were no significant differences in the post-treatment tumor volume and the volume reduction ratio shown by 3D MR volumetry with respect to T and N downstaging and the tumor regression grade. In a multivariate analysis, the tumor volume reduction ratio was not significantly associated with T and N downstaging. The volume reduction ratio (>75%, p = 0.01) and the pretreatment carcinoembryonic antigen level (≤3 ng/ml, p = 0.01), but not the post-treatment volume shown by 3D MR (≤ 5ml), were, however, significantly associated with an increased pathologic complete response rate. Conclusion: More than 75% of the tumor volume reduction ratios were significantly associated with a high pathologic complete response rate. Therefore, limited treatment options such as local excision or simple observation might be considered after preoperative CRT in this patient population.

  8. Development of a two-dimensional high-performance liquid chromatography system coupled with on-line reduction as a new efficient analytical method of 3-nitrobenzanthrone, a potential human carcinogen.

    Science.gov (United States)

    Hasei, Tomohiro; Nakanishi, Haruka; Toda, Yumiko; Watanabe, Tetsushi

    2012-08-31

    3-Nitrobenzanthrone (3-NBA) is an extremely strong mutagen and carcinogen in rats inducing squamous cell carcinoma and adenocarcinoma. We developed a new sensitive analytical method, a two-dimensional HPLC system coupled with on-line reduction, to quantify non-fluorescent 3-NBA as fluorescent 3-aminobenzanthrone (3-ABA). The two-dimensional HPLC system consisted of reversed-phase HPLC and normal-phase HPLC, which were connected with a switch valve. 3-NBA was purified by reversed-phase HPLC and reduced to 3-ABA with a catalyst column, packed with alumina coated with platinum, in ethanol. An alcoholic solvent is necessary for reduction of 3-NBA, but 3-ABA is not fluorescent in the alcoholic solvent. Therefore, 3-ABA was separated from alcohol and impurities by normal-phase HPLC and detected with a fluorescence detector. Extracts from surface soil, airborne particles, classified airborne particles, and incinerator dust were applied to the two-dimensional HPLC system after clean-up with a silica gel column. 3-NBA, detected as 3-ABA, in the extracts was found as a single peak on the chromatograms without any interfering peaks. 3-NBA was detected in 4 incinerator dust samples (n=5). When classified airborne particles, that is, those 7.0 μm in size, were applied to the two-dimensional HPLC system after purified using a silica gel column, 3-NBA was detected in those particles with particle sizes NBA in airborne particles and the detection of 3-NBA in incinerator dust. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Efficacy and safety of a multifactor intervention to improve therapeutic adherence in patients with chronic obstructive pulmonary disease (COPD: protocol for the ICEPOC study

    Directory of Open Access Journals (Sweden)

    Prados-Torres Daniel

    2011-02-01

    Full Text Available Abstract Background Low therapeutic adherence to medication is very common. Clinical effectiveness is related to dose rate and route of administration and so poor therapeutic adherence can reduce the clinical benefit of treatment. The therapeutic adherence of patients with chronic obstructive pulmonary disease (COPD is extremely poor according to most studies. The research about COPD adherence has mainly focussed on quantifying its effect, and few studies have researched factors that affect non-adherence. Our study will evaluate the effectiveness of a multifactor intervention to improve the therapeutic adherence of COPD patients. Methods/Design A randomized controlled clinical trial with 140 COPD diagnosed patients selected by a non-probabilistic method of sampling. Subjects will be randomly allocated into two groups, using the block randomization technique. Every patient in each group will be visited four times during the year of the study. Intervention: Motivational aspects related to adherence (beliefs and behaviour: group and individual interviews; cognitive aspects: information about illness; skills: inhaled technique training. Reinforcement of the cognitive-emotional aspects and inhaled technique training will be carried out in all visits of the intervention group. Discussion Adherence to a prescribed treatment involves a behavioural change. Cognitive, emotional and motivational aspects influence this change and so we consider the best intervention procedure to improve adherence would be a cognitive and emotional strategy which could be applied in daily clinical practice. Our hypothesis is that the application of a multifactor intervention (COPD information, dose reminders and reinforcing audiovisual material, motivational aspects and inhalation technique training to COPD patients taking inhaled treatment will give a 25% increase in the number of patients showing therapeutic adherence in this group compared to the control group. We will

  10. COVAR: Computer Program for Multifactor Relative Risks and Tests of Hypotheses Using a Variance-Covariance Matrix from Linear and Log-Linear Regression

    Directory of Open Access Journals (Sweden)

    Leif E. Peterson

    1997-11-01

    Full Text Available A computer program for multifactor relative risks, confidence limits, and tests of hypotheses using regression coefficients and a variance-covariance matrix obtained from a previous additive or multiplicative regression analysis is described in detail. Data used by the program can be stored and input from an external disk-file or entered via the keyboard. The output contains a list of the input data, point estimates of single or joint effects, confidence intervals and tests of hypotheses based on a minimum modified chi-square statistic. Availability of the program is also discussed.

  11. A Variational Reduction and the Existence of a Fully Localised Solitary Wave for the Three-Dimensional Water-Wave Problem with Weak Surface Tension

    Science.gov (United States)

    Buffoni, Boris; Groves, Mark D.; Wahlén, Erik

    2018-06-01

    Fully localised solitary waves are travelling-wave solutions of the three- dimensional gravity-capillary water wave problem which decay to zero in every horizontal spatial direction. Their existence has been predicted on the basis of numerical simulations and model equations (in which context they are usually referred to as `lumps'), and a mathematically rigorous existence theory for strong surface tension (Bond number {β} greater than {1/3}) has recently been given. In this article we present an existence theory for the physically more realistic case {0 point of the reduced functional is found by minimising it over its natural constraint set.

  12. Quasi-one-dimensional polaronic states due to the preferential reduction in the Li sub 1 sub + sub x V sub 3 O sub 8 insertion electrode

    CERN Document Server

    Onoda, M

    2003-01-01

    The structural and electronic properties of the Li sub 1 sub + sub x V sub 3 O sub 8 insertion electrode, where 0 sup 0.1 with nearly stoichiometric oxygen atoms, small polarons exist without carrier-creation energy at high temperatures, while at low temperatures the conduction may be of variable-range hopping (VRH) type. For x > 0.2, one-dimensional magnetic properties appear due to sizable exchange couplings and order-disorder effects of additional Li ions may lead to significant change of transport properties. For the intermediate composition 0 < x sup<= 0.1, strong randomness of the Li doping and the congenital oxygen deficiency cause VRH states even at high temperatures.

  13. Truncated Painleve expansion: Tanh-traveling wave solutions and reduction of sine-Poisson equation to a quadrature for stationary and nonstationary three-dimensional collisionless cold plasma

    International Nuclear Information System (INIS)

    Ibrahim, R. S.; El-Kalaawy, O. H.

    2006-01-01

    The relativistic nonlinear self-consistent equations for a collisionless cold plasma with stationary ions [R. S. Ibrahim, IMA J. Appl. Math. 68, 523 (2003)] are extended to 3 and 3+1 dimensions. The resulting system of equations is reduced to the sine-Poisson equation. The truncated Painleve expansion and reduction of the partial differential equation to a quadrature problem (RQ method) are described and applied to obtain the traveling wave solutions of the sine-Poisson equation for stationary and nonstationary equations in 3 and 3+1 dimensions describing the charge-density equilibrium configuration model

  14. Facile synthesis of silver nanoparticles supported on three dimensional graphene oxide/carbon black composite and its application for oxygen reduction reaction

    International Nuclear Information System (INIS)

    Yuan, Lizhi; Jiang, Luhua; Liu, Jing; Xia, Zhangxun; Wang, Suli; Sun, Gongquan

    2014-01-01

    Graphical abstract: - Highlights: • Ag nanoparticles were prepared using GO as reductant without any stabilizers. • A composite support with a 3D structure was constructed by GO and carbon black. • The Ag/GO/C composite shows enhanced ORR activity compared with Ag/GO. - Abstract: A 3D graphene oxide/carbon sphere supported silver composite (Ag/GO/C) was synthesized using graphene oxide as the reducing agent. The reducing process of Ag + was monitored by the ultra violet-visible (UV-vis) absorption spectrometer and the physical properties of the Ag/GO/C composite were characterized by Fourier transform infrared spectrometer (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the dispersive Ag nanoparticles are anchored uniformly on the surface of GO sheets with a mean size of about 6.9 nm. With introducing carbon black, the Ag nanoparticles aggregated slightly. Compared with its counterpart Ag/GO, the Ag/GO/C composite showed a significantly enhanced activity towards the oxygen reduction reaction in alkaline media. The enhancement can be ascribed to the 3D composite support, which not only improves the electrical conductivity, but also enforces the mass transport in the catalyst layer facilitating the reactants access to the active sites. Moreover, the Ag/GO/C composite exhibits good tolerance to alcohols, carbonates and tetramethylammonium hydroxide. This work is expected to open a new pathway to use GO as a reducing agent to synthesize electrocatalysts without surfactants

  15. Preoperative assessment of pleural adhesion by Four-Dimensional Ultra-Low-Dose Computed Tomography (4D-ULDCT) with Adaptive Iterative Dose Reduction using Three-Dimensional processing (AIDR-3D).

    Science.gov (United States)

    Hashimoto, Masayuki; Nagatani, Yukihiro; Oshio, Yasuhiko; Nitta, Norihisa; Yamashiro, Tsuneo; Tsukagoshi, Shinsuke; Ushio, Noritoshi; Mayumi, Masayuki; Kimoto, Tatsuya; Igarashi, Tomoyuki; Yoshigoe, Makoto; Iwai, Kyohei; Tanaka, Koki; Sato, Shigetaka; Sonoda, Akinaga; Otani, Hideji; Murata, Kiyoshi; Hanaoka, Jun

    2018-01-01

    To assess the feasibility of Four-Dimensional Ultra-Low-Dose Computed Tomography (4D-ULDCT) for distinguishing pleural aspects with localized pleural adhesion (LPA) from those without. Twenty-seven patients underwent 4D-ULDCT during a single respiration with a 16cm-coverage of the body axis. The presence and severity of LPA was confirmed by their intraoperative thoracoscopic findings. A point on the pleura and a corresponding point on the outer edge of the costal bone were placed in identical axial planes at end-inspiration. The distance of the two points (PCD), traced by automatic tracking functions respectively, was calculated at each respiratory phase. The maximal and average change amounts in PCD (PCD MCA and PCD ACA ) were compared among 110 measurement points (MPs) without LPA, 16MPs with mild LPA and 10MPs with severe LPA in upper lung field cranial to the bronchial bifurcation (ULF), and 150MPs without LPA, 17MPs with mild LPA and 9MPs with severe LPA in lower lung field caudal to the bronchial bifurcation (LLF) using the Mann-Whitney U test. In the LLF, PCD ACA as well as PCD MCA demonstrated a significant difference among non-LPA, mild LPA and severe LPA (18.1±9.2, 12.3±6.2 and 5.0±3.3mm) (p<0.05). Also in the ULF, PCD ACA showed a significant difference among three conditions (9.2±5.5, 5.7±2.8 and 2.2±0.4mm, respectively) (p<0.05), whereas PCD MCA for mild LPA was similar to that for non-LPA (12.3±5.9 and 17.5±11.0mm). Four D-ULDCT could be a useful non-invasive preoperative assessment modality for the detection of the presence or severity of LPA. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Climate change impacts: The challenge of quantifying multi-factor causation, multi-component responses, and leveraging from extremes

    Science.gov (United States)

    Field, C. B.

    2012-12-01

    area is the ability to utilize data of uneven quality and standards. Novel approaches to meta-analysis provide other options for taking advantage of diverse case studies. Techniques for summarizing responses across impacts, drivers, and scales can play a huge role in increasing the value of information from case studies. In some cases, expert elicitation may provide alternatives for identifying mechanisms or for interpreting multi-factor drivers or responses. Especially when designed to focus on a well-defined set of observations, a sophisticated elicitation can establish formal confidence limits on responses that are otherwise difficult to constrain. A final possible approach involves a focus on the mechanisms contributing to an impact, rather than the impact itself. Approaches based on quantified mechanisms are especially appealing in the context of models where the number of interactions makes it difficult to intuitively understand the chain of connections from cause to effect, when actors differ in goals or sensitivities, or when scale affects parts of the system differently. With all of these approaches, useful evidence may not conform to traditional levels of statistical confidence. Some of the biggest challenges in taking advantage of the potential tools will involve defining what constitutes a meaningful evaluation.

  17. Facile preparation of efficient electrocatalysts for oxygen reduction reaction: One-dimensional meso/macroporous cobalt and nitrogen Co-doped carbon nanofibers

    Science.gov (United States)

    Yoon, Ki Ro; Choi, Jinho; Cho, Su-Ho; Jung, Ji-Won; Kim, Chanhoon; Cheong, Jun Young; Kim, Il-Doo

    2018-03-01

    Efficient electrocatalyst for oxygen reduction reaction (ORR) is an essential component for stable operation of various sustainable energy conversion and storage systems such as fuel cells and metal-air batteries. Herein, we report a facile preparation of meso/macroporous Co and N co-doped carbon nanofibers (Co-Nx@CNFs) as a high performance and cost-effective electrocatalyst toward ORR. Co-Nx@CNFs are simply obtained from electrospinning of Co precursor and bicomponent polymers (PVP/PAN) followed by temperature controlled carbonization and further activation step. The prepared Co-Nx@CNF catalyst carbonized at 700 °C (Co-Nx@CNF700) shows outstanding ORR performance, i.e., a low onset potential (0.941 V) and half wave potential (0.814 V) with almost four-electron transfer pathways (n= 3.9). In addition, Co-Nx@CNF700 exhibits a superior methanol tolerance and higher stability (>70 h) in Zn-air battery in comparison with Pt/C catalyst (∼30 h). The outstanding performance of Co-Nx@CNF700 catalysts is attributed to i) enlarged surface area with bimodal porosity achieved by leaching of inactive species, ii) increase of exposed ORR active Co-Nx moieties and graphitic edge sites, and iii) enhanced electrical conductivity and corrosion resistance due to the existence of numerous graphitic flakes in carbon matrix.

  18. High index surfaces of Au-nanocrystals supported on one-dimensional MoO3-nanorod as a bi-functional electrocatalyst for ethanol oxidation and oxygen reduction

    International Nuclear Information System (INIS)

    Karuppasamy, L.; Chen, C.Y.; Anandan, S.; Wu, J.J.

    2017-01-01

    Highlights: •Synthesis of a new class of Au nanocrystals enclosed with high index surface supported on MoO 3 nanorods by ultrasonic probe method. •The role of supporting materials reduces the loading of Au and acts as a co-catalyst. •The as prepared electrocatalyst exhibits enhanced catalytic activity and stability towards both EOR and ORR. -- Abstract: The design of highly active electrocatalyst for ethanol electrooxidation (EOR) and oxygen reduction reaction (ORR) is of great significance for the improvement of efficient direct ethanol fuel cells (DEFCs). Therefore, creating high index facets nanocrystals with abundant catalytic active sites of stepped atoms is an effective way to enhance the electrocatalytic performance. In this article, we prepared the high index surface structures of Au nanocrystals supported on one-dimensional (1-D) MoO 3 nanorods by using two steps ultrasonic probe irradiation method. The size and physical properties of as electrocatalysts were studied by using field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and x-ray diffraction (XRD) instrumentation. Besides, the catalytic activity of as Au-MoO 3 electrocatalyst was determined by using cyclic voltammetry (CV), chronoamperometric (CA), electrochemical impedance spectroscopy (EIS), CO-stripping, and linear sweep voltammetry-rotating disk electrode (LSV-RDE). As a consequence, the Au-MoO 3 nanocomposites has been considered as an effective electrocatalyst for both ethanol oxidation and oxygen reduction reaction.

  19. An overview of a multifactor-system theory of personality and individual differences: III. Life span development and the heredity-environment issue.

    Science.gov (United States)

    Powell, A; Royce, J R

    1981-12-01

    In Part III of this three-part series on multifactor-system theory, multivariate, life-span development is approached from the standpoint of a quantitative and qualitative analysis of the ontogenesis of factors in each of the six systems. The pattern of quantitative development (described via the Gompertz equation and three developmental parameters) involves growth, stability, and decline, and qualitative development involves changes in the organization of factors (e.g., factor differentiation and convergence). Hereditary and environmental sources of variation are analyzed via the factor gene model and the concept of heredity-dominant factors, and the factor-learning model and environment-dominant factors. It is hypothesized that the sensory and motor systems are heredity dominant, that the style and value systems are environment dominant, and that the cognitive and affective systems are partially heredity dominant.

  20. Modeling of Alpine Grassland Cover Based on Unmanned Aerial Vehicle Technology and Multi-Factor Methods: A Case Study in the East of Tibetan Plateau, China

    Directory of Open Access Journals (Sweden)

    Baoping Meng

    2018-02-01

    Full Text Available Grassland cover and its temporal changes are key parameters in the estimation and monitoring of ecosystems and their functions, especially via remote sensing. However, the most suitable model for estimating grassland cover and the differences between models has rarely been studied in alpine meadow grasslands. In this study, field measurements of grassland cover in Gannan Prefecture, from 2014 to 2016, were acquired using unmanned aerial vehicle (UAV technology. Single-factor parametric and multi-factor parametric/non-parametric cover inversion models were then constructed based on 14 factors related to grassland cover, and the dynamic variation of the annual maximum cover was analyzed. The results show that (1 nine out of 14 factors (longitude, latitude, elevation, the concentrations of clay and sand in the surface and bottom soils, temperature, precipitation, enhanced vegetation index (EVI and normalized difference vegetation index (NDVI exert a significant effect on grassland cover in the study area. The logarithmic model based on EVI presents the best performance, with an R2 and RMSE of 0.52 and 16.96%, respectively. Single-factor grassland cover inversion models account for only 1–49% of the variation in cover during the growth season. (2 The optimum grassland cover inversion model is the artificial neural network (BP-ANN, with an R2 and RMSE of 0.72 and 13.38%, and SDs of 0.062% and 1.615%, respectively. Both the accuracy and the stability of the BP-ANN model are higher than those of the single-factor parametric models and multi-factor parametric/non-parametric models. (3 The annual maximum cover in Gannan Prefecture presents an increasing trend over 60.60% of the entire study area, while 36.54% is presently stable and 2.86% exhibits a decreasing trend.

  1. Exploring Dimensionality Reduction for Text Mining

    Science.gov (United States)

    2007-05-04

    result is v: v = √ K2 · 1 (3.20) 6) Define K3 to be the element-by-element division of K2 by the product of v and its transpose: K3i,j = K2i,j/(v · vT...3.21) 30 7) Compute the singular value decomposition of K3 to get U , D, and V as specified in Equation 3.5. 8) The output points can then be...adequate safety studies. Procter and Gamble agrees that olestra helps carry away fat-soluble vitamins such as A, D, E, and K. Indeed, the firm plans to

  2. Two-color QCD via dimensional reduction

    Czech Academy of Sciences Publication Activity Database

    Zhang, T.; Brauner, Tomáš; Kurkela, A.; Vuorinen, A.

    2012-01-01

    Roč. 2012, č. 139 (2012), s. 1-16 ISSN 1126-6708 Institutional support: RVO:61389005 Keywords : thermal field theory * QCD * confinement Subject RIV: BE - Theoretical Physics Impact factor: 5.618, year: 2012

  3. Deep Belief Networks for dimensionality reduction

    NARCIS (Netherlands)

    Noulas, A.K.; Kröse, B.J.A.

    2008-01-01

    Deep Belief Networks are probabilistic generative models which are composed by multiple layers of latent stochastic variables. The top two layers have symmetric undirected connections, while the lower layers receive directed top-down connections from the layer above. The current state-of-the-art

  4. Reduction of vascular artifact on T1-weighted images of the brain by using three-dimensional double IR fast spoiled gradient echo recalled acquisition in the steady state (FSPGR) at 3.0 Tesla

    International Nuclear Information System (INIS)

    Fujiwara, Yasuhiro; Yamaguchi, Isao; Ookoshi, Yusuke; Ootani, Yuriko; Matsuda, Tsuyoshi; Ishimori, Yoshiyuki; Hayashi, Hiroyuki; Miyati, Tosiaki; Kimura, Hirohiko

    2007-01-01

    The purpose of this study was to decrease vascular artifacts caused by the in-flow effect in three-dimensional inversion recovery prepared fast spoiled gradient recalled acquisition in the steady state (3D IR FSPGR) at 3.0 Tesla. We developed 3D double IR FSPGR and investigated the signal characteristics of the new sequence. The 3D double IR FSPGR sequence uses two inversion pulses, the first for obtaining tissue contrast and the second for nulling vascular signal, which is applied at the time of the first IR period at the neck region. We have optimized scan parameters based on both phantom and in-vivo study. As a result, optimized parameters (1st TI=700 ms, 2nd TI=400 ms) successfully have produced much less vessel signal at reduction than conventional 3D IR FSPGR over a wide imaging range, while preserving the signal-to-noise ratio (SNR) and gray/white matter contrast. Moreover, the decreased artifact was also confirmed by visual inspection of the images obtained in vivo using those parameters. Thus, 3D double IR FSPGR was a useful sequence for the acquisition of T1-weighted images at 3.0 Tesla. (author)

  5. Two-Dimensional N,S-Codoped Carbon/Co 9 S 8 Catalysts Derived from Co(OH) 2 Nanosheets for Oxygen Reduction Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Shaofang [School of Mechanical; Zhu, Chengzhou [School of Mechanical; Song, Junhua [School of Mechanical; Feng, Shuo [School of Mechanical; Du, Dan [School of Mechanical; Key Laboratory of Pesticide and Chemical; Engelhard, Mark H. [Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Xiao, Dongdong [Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Li, Dongsheng [Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Lin, Yuehe [School of Mechanical

    2017-10-12

    Investigation of highly active and cost-efficient electrocatalysts for oxygen reduction reaction is of great importance in a wide range of clean energy devices, including fuel cells and metal-air batteries. Herein, the simultaneous formation of Co9S8 and N,S-codoped carbon was achieved in a dual templates system. First, Co(OH)2 nanosheets and tetraethyl orthosilicate were utilized to direct the formation of two-dimensional carbon precursors, which were then dispersed into thiourea solution. After subsequent pyrolysis and templates removal, N/S-codoped porous carbon sheets confined Co9S8 catalysts (Co9S8/NSC) were obtained. Owing to the morphological and compositional advantages as well as the synergistic effects, the resultant Co9S8/NSC catalysts with modified doping level and pyrolysis degree exhibit superior ORR catalytic activity and long-term stability compared with the state-of-the-art Pt/C catalyst in alkaline media. Remarkably, the as-prepared carbon composites also reveal exceptional tolerance of methanol, indicating their potential applications in fuel cells.

  6. Assessment of the reduction methods used to develop chemical schemes: building of a new chemical scheme for VOC oxidation suited to three-dimensional multiscale HOx-NOx-VOC chemistry simulations

    Directory of Open Access Journals (Sweden)

    S. Szopa

    2005-01-01

    Full Text Available The objective of this work was to develop and assess an automatic procedure to generate reduced chemical schemes for the atmospheric photooxidation of volatile organic carbon (VOC compounds. The procedure is based on (i the development of a tool for writing the fully explicit schemes for VOC oxidation (see companion paper Aumont et al., 2005, (ii the application of several commonly used reduction methods to the fully explicit scheme, and (iii the assessment of resulting errors based on direct comparison between the reduced and full schemes. The reference scheme included seventy emitted VOCs chosen to be representative of both anthropogenic and biogenic emissions, and their atmospheric degradation chemistry required more than two million reactions among 350000 species. Three methods were applied to reduce the size of the reference chemical scheme: (i use of operators, based on the redundancy of the reaction sequences involved in the VOC oxidation, (ii grouping of primary species having similar reactivities into surrogate species and (iii grouping of some secondary products into surrogate species. The number of species in the final reduced scheme is 147, this being small enough for practical inclusion in current three-dimensional models. Comparisons between the fully explicit and reduced schemes, carried out with a box model for several typical tropospheric conditions, showed that the reduced chemical scheme accurately predicts ozone concentrations and some other aspects of oxidant chemistry for both polluted and clean tropospheric conditions.

  7. The Multi-factor Predictive Seis &Gis Model of Ecological, Genetical, Population Health Risk and Bio-geodynamic Processes In Geopathogenic Zones

    Science.gov (United States)

    Bondarenko, Y.

    I. Goal and Scope. Human birth rate decrease, death-rate growth and increase of mu- tagenic deviations risk take place in geopathogenic and anthropogenic hazard zones. Such zones create unfavourable conditions for reproductive process of future genera- tions. These negative trends should be considered as a protective answer of the com- plex biosocial system to the appearance of natural and anthropogenic risk factors that are unfavourable for human health. The major goals of scientific evaluation and de- crease of risk of appearance of hazardous processes on the territory of Dnipropetrovsk, along with creation of the multi-factor predictive Spirit-Energy-Information Space "SEIS" & GIS Model of ecological, genetical and population health risk in connection with dangerous bio-geodynamic processes, were: multi-factor modeling and correla- tion of natural and anthropogenic environmental changes and those of human health; determination of indicators that show the risk of destruction structures appearance on different levels of organization and functioning of the city ecosystem (geophys- ical and geochemical fields, soil, hydrosphere, atmosphere, biosphere); analysis of regularities of natural, anthropogenic, and biological rhythms' interactions. II. Meth- ods. The long spatio-temporal researches (Y. Bondarenko, 1996, 2000) have proved that the ecological, genetic and epidemiological processes are in connection with de- velopment of dangerous bio-geophysical and bio-geodynamic processes. Mathemat- ical processing of space photos, lithogeochemical and geophysical maps with use of JEIS o and ERDAS o computer systems was executed at the first stage of forma- tion of multi-layer geoinformation model "Dnipropetrovsk ARC View GIS o. The multi-factor nonlinear correlation between solar activity and cosmic ray variations, geophysical, geodynamic, geochemical, atmospheric, technological, biological, socio- economical processes and oncologic case rate frequency, general and primary

  8. Supersymmetric dimensional regularization

    International Nuclear Information System (INIS)

    Siegel, W.; Townsend, P.K.; van Nieuwenhuizen, P.

    1980-01-01

    There is a simple modification of dimension regularization which preserves supersymmetry: dimensional reduction to real D < 4, followed by analytic continuation to complex D. In terms of component fields, this means fixing the ranges of all indices on the fields (and therefore the numbers of Fermi and Bose components). For superfields, it means continuing in the dimensionality of x-space while fixing the dimensionality of theta-space. This regularization procedure allows the simple manipulation of spinor derivatives in supergraph calculations. The resulting rules are: (1) First do all algebra exactly as in D = 4; (2) Then do the momentum integrals as in ordinary dimensional regularization. This regularization procedure needs extra rules before one can say that it is consistent. Such extra rules needed for superconformal anomalies are discussed. Problems associated with renormalizability and higher order loops are also discussed

  9. Benchmarking energy performance of residential buildings using two-stage multifactor data envelopment analysis with degree-day based simple-normalization approach

    International Nuclear Information System (INIS)

    Wang, Endong; Shen, Zhigang; Alp, Neslihan; Barry, Nate

    2015-01-01

    Highlights: • Two-stage DEA model is developed to benchmark building energy efficiency. • Degree-day based simple normalization is used to neutralize the climatic noise. • Results of a real case study validated the benefits of this new model. - Abstract: Being able to identify detailed meta factors of energy performance is essential for creating effective residential energy-retrofitting strategies. Compared to other benchmarking methods, nonparametric multifactor DEA (data envelopment analysis) is capable of discriminating scale factors from management factors to reveal more details to better guide retrofitting practices. A two-stage DEA energy benchmarking method is proposed in this paper. This method includes (1) first-stage meta DEA which integrates the common degree day metrics for neutralizing noise energy effects of exogenous climatic variables; and (2) second-stage Tobit regression for further detailed efficiency analysis. A case study involving 3-year longitudinal panel data of 189 residential buildings indicated the proposed method has advantages over existing methods in terms of its efficiency in data processing and results interpretation. The results of the case study also demonstrated high consistency with existing linear regression based DEA.

  10. A multi-factor model of panic disorder: results of a preliminary study integrating the role of perfectionism, stress, physiological anxiety and anxiety sensitivity

    Directory of Open Access Journals (Sweden)

    Cristina M. Wood

    2015-05-01

    Full Text Available Background: Panic disorder (PD is a highly prevalent and disabling mental health problem associated with different factors including perfectionism, stress, physiological anxiety, and anxiety sensitivity regarding physical concerns; however, no studies have analyzed the joint relationship between these factors and PD in a multi-factor model using structural equation modeling. Method: A cross-sectional study was carried out to collect data on these factors and self-reported DSM-IV past-year PD symptoms in a large sample of the general population (N=936. Results: Perceived stress had a significant effect in increasing physiological anxiety, which in turn had an important association with physical concerns. Perfectionism and perceived stress had an indirect relation with past year PD via the mediator role of physiological anxiety and physical concerns. Physical concerns, on one hand, seemed to mediate the impact between perfectionism and PD and, on the other, partially mediated the role between physiological anxiety and PD. Conclusions: Although there is considerable evidence on the association between each of these factors and PD, this model can be considered a broader and productive framework of research on the nature and treatment of PD.

  11. Diffusion trajectory of self-propagating innovations interacting with institutions-incorporation of multi-factors learning function to model PV diffusion in Japan

    International Nuclear Information System (INIS)

    Nagamatsu, Akira; Watanabe, Chihiro; Shum, Kwok L.

    2006-01-01

    This paper first proposes a modeling framework to study diffusion of innovations which exhibit strong interaction with the institution systems across which they diffuse. A unique character of such generic innovation is that specific applications are continually developed during its diffusion. This self-propagation in continual applications generation, which is dependent upon the cumulative installed base of the technological innovation, can be modeled to lead to a dynamic changing carrying capacity in an otherwise simple logistic diffusion curve. The cumulative installed base is dependent upon the price of technology and the cost learning dynamics. This paper utilizes a multi-factors learning function to represent such learning dynamics. Empirical estimates from our model are compared with those from other logistics curve formulations and are shown to better fit the annual PV production data during the past quarter century in the case of Japan. The very fact that the potential of this class of innovation can be leveraged only if it interacts closely with the institution highlights the importance of institutional determinants of adoption and diffusion of such innovations like PV. We therefore attempt to put forward an institutional framework, based on viewing PV as a technology platform, to consider PV diffusion beyond mathematical and empirical modeling. Some future research directions are also proposed. (author)

  12. Robust methods for data reduction

    CERN Document Server

    Farcomeni, Alessio

    2015-01-01

    Robust Methods for Data Reduction gives a non-technical overview of robust data reduction techniques, encouraging the use of these important and useful methods in practical applications. The main areas covered include principal components analysis, sparse principal component analysis, canonical correlation analysis, factor analysis, clustering, double clustering, and discriminant analysis.The first part of the book illustrates how dimension reduction techniques synthesize available information by reducing the dimensionality of the data. The second part focuses on cluster and discriminant analy

  13. Reduction redux.

    Science.gov (United States)

    Shapiro, Lawrence

    2018-04-01

    Putnam's criticisms of the identity theory attack a straw man. Fodor's criticisms of reduction attack a straw man. Properly interpreted, Nagel offered a conception of reduction that captures everything a physicalist could want. I update Nagel, introducing the idea of overlap, and show why multiple realization poses no challenge to reduction so construed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Soil health in the Mediterranean region: Development and consolidation of a multifactor index to characterize the health of agricultural lands

    Science.gov (United States)

    Gil, Eshel; Guy, Levy; Oshri, Rinot; Michael, Borisover; Uri, Yermiyahu; Leah, Tsror; Hanan, Eizenberg; Tal, Svoray; Alex, Furman; Yael, Mishael; Yosef, Steinberger

    2017-04-01

    The link among between soil health, soil conservation, and food security, resilience, and function under a wide range of agricultural uses and different environmental systems, is at the heart of many ecofriendly research studies worldwide. We consider the health of soil as a function of its ability to provide ecosystem services, including agricultural production (provisional services); regulating natural cycles (regulation services) and as a habitat for plants (support services). Soil health is affected by a wide range of soil properties (biotic and abiotic) that maintain complex interactions among themselves. The decline in soil health includes degradation in its physical properties (e.g., deterioration of soil structure, compaction and sealing, water-repellency, soil erosion by water and wind), chemical properties (e.g., salinization, depletion of nutrients and organic matter content, accumulation of pollutants and reduction of the soils' ion exchange capacity) and biological properties (e.g., vulnerable populations of microflora, microfauna, and mesofauna, leading to a breach of ecological balance and biodiversity and, as a result, destruction of beneficial populations and pathogen outbreaks). Numerous studies show that agricultural practices have a major impact on soil functioning. Substituting longstanding tillage with no-till cropping and the amalgamation of cover crops in crop rotations were found to improve soil properties. Such changes contributed to the enhancement of the agronomical performance of the soil. On the other hand, these practices may result in lessened effectiveness of controlling perennial weeds. The evaluation of soil-health status in the Mediterranean region is very limited. Moreover, existing approaches for evaluation that have been used (such as the Cornell and Hany tests) do not give sufficient weight to important agronomic processes, such as soil erosion, salinization, sodification, spread of weeds in the fields (in particular, weeds

  15. Learning in robotic manipulation: The role of dimensionality reduction in policy search methods. Comment on "Hand synergies: Integration of robotics and neuroscience for understanding the control of biological and artificial hands" by Marco Santello et al.

    Science.gov (United States)

    Ficuciello, Fanny; Siciliano, Bruno

    2016-07-01

    A question that often arises, among researchers working on artificial hands and robotic manipulation, concerns the real meaning of synergies. Namely, are they a realistic representation of the central nervous system control of manipulation activities at different levels and of the sensory-motor manipulation apparatus of the human being, or do they constitute just a theoretical framework exploiting analytical methods to simplify the representation of grasping and manipulation activities? Apparently, this is not a simple question to answer and, in this regard, many minds from the field of neuroscience and robotics are addressing the issue [1]. The interest of robotics is definitely oriented towards the adoption of synergies to tackle the control problem of devices with high number of degrees of freedom (DoFs) which are required to achieve motor and learning skills comparable to those of humans. The synergy concept is useful for innovative underactuated design of anthropomorphic hands [2], while the resulting dimensionality reduction simplifies the control of biomedical devices such as myoelectric hand prostheses [3]. Synergies might also be useful in conjunction with the learning process [4]. This aspect is less explored since few works on synergy-based learning have been realized in robotics. In learning new tasks through trial-and-error, physical interaction is important. On the other hand, advanced mechanical designs such as tendon-driven actuation, underactuated compliant mechanisms and hyper-redundant/continuum robots might exhibit enhanced capabilities of adapting to changing environments and learning from exploration. In particular, high DoFs and compliance increase the complexity of modelling and control of these devices. An analytical approach to manipulation planning requires a precise model of the object, an accurate description of the task, and an evaluation of the object affordance, which all make the process rather time consuming. The integration of

  16. Dimensional Analysis

    Indian Academy of Sciences (India)

    Dimensional analysis is a useful tool which finds important applications in physics and engineering. It is most effective when there exist a maximal number of dimensionless quantities constructed out of the relevant physical variables. Though a complete theory of dimen- sional analysis was developed way back in 1914 in a.

  17. Reduction corporoplasty.

    Science.gov (United States)

    Hakky, Tariq S; Martinez, Daniel; Yang, Christopher; Carrion, Rafael E

    2015-01-01

    Here we present the first video demonstration of reduction corporoplasty in the management of phallic disfigurement in a 17 year old man with a history sickle cell disease and priapism. Surgical management of aneurysmal dilation of the corpora has yet to be defined in the literature. We preformed bilateral elliptical incisions over the lateral corpora as management of aneurysmal dilation of the corpora to correct phallic disfigurement. The patient tolerated the procedure well and has resolution of his corporal disfigurement. Reduction corporoplasty using bilateral lateral elliptical incisions in the management of aneurysmal dilation of the corpora is a safe an feasible operation in the management of phallic disfigurement.

  18. Recursions of Symmetry Orbits and Reduction without Reduction

    Directory of Open Access Journals (Sweden)

    Andrei A. Malykh

    2011-04-01

    Full Text Available We consider a four-dimensional PDE possessing partner symmetries mainly on the example of complex Monge-Ampère equation (CMA. We use simultaneously two pairs of symmetries related by a recursion relation, which are mutually complex conjugate for CMA. For both pairs of partner symmetries, using Lie equations, we introduce explicitly group parameters as additional variables, replacing symmetry characteristics and their complex conjugates by derivatives of the unknown with respect to group parameters. We study the resulting system of six equations in the eight-dimensional space, that includes CMA, four equations of the recursion between partner symmetries and one integrability condition of this system. We use point symmetries of this extended system for performing its symmetry reduction with respect to group parameters that facilitates solving the extended system. This procedure does not imply a reduction in the number of physical variables and hence we end up with orbits of non-invariant solutions of CMA, generated by one partner symmetry, not used in the reduction. These solutions are determined by six linear equations with constant coefficients in the five-dimensional space which are obtained by a three-dimensional Legendre transformation of the reduced extended system. We present algebraic and exponential examples of such solutions that govern Legendre-transformed Ricci-flat Kähler metrics with no Killing vectors. A similar procedure is briefly outlined for Husain equation.

  19. Topotactic reduction as a synthetic route for the preparation of low-dimensional Mn(II) oxide phases: the structure and magnetism of LaAMnO(4-x) (A = Sr, Ba).

    Science.gov (United States)

    Kitchen, Helen J; Saratovsky, Ian; Hayward, Michael A

    2010-07-14

    Reaction of LaSrMnO(4) with CaH(2) at 420 degrees C yields LaSrMnO(3.67(3)). Raising the temperature to 480 degrees C yields the Mn(II) phase LaSrMnO(3.50(2)). Neutron powder diffraction data show both phases adopt body-centred orthorhombic crystal structures (LaSrMnO(3.67(3)), Immm: a = 3.7256(1) A, b = 3.8227(1) A, c = 13.3617(4) A; LaSrMnO(3.50(2)), Immm: a = 3.7810(1) A, b = 3.7936(1) A, c = 13.3974(3) A) with anion vacancies located within the equatorial MnO(2-x) planes of the materials. Analogous reactivity is observed between LaBaMnO(4) and CaH(2) to yield body-centred tetragonal reduced phases (LaBaMnO(3.53(3)), I4/mmm: a = 3.8872(1)A, c = 13.6438(2) A). Low-temperature neutron diffraction and magnetisation data show that LaSrMnO(3.5) and LaBaMnO(3.5) exhibit three-dimensional antiferromagnetic order below 155 K and 135 K respectively. Above these temperatures, they exhibit two-dimensional antiferromagnetic order with paramagnetic behaviour observed above 480 K in both phases. The origin of the low dimensional magnetic order and ordering of the anion vacancies in the reduced phases is discussed.

  20. Reduction Corporoplasty

    Directory of Open Access Journals (Sweden)

    Tariq S. Hakky

    2015-04-01

    Full Text Available Objective Here we present the first video demonstration of reduction corporoplasty in the management of phallic disfigurement in a 17 year old man with a history sickle cell disease and priapism. Introduction Surgical management of aneurysmal dilation of the corpora has yet to be defined in the literature. Materials and Methods: We preformed bilateral elliptical incisions over the lateral corpora as management of aneurysmal dilation of the corpora to correct phallic disfigurement. Results The patient tolerated the procedure well and has resolution of his corporal disfigurement. Conclusions Reduction corporoplasty using bilateral lateral elliptical incisions in the management of aneurysmal dilation of the corpora is a safe an feasible operation in the management of phallic disfigurement.

  1. Radioactive waste isolation in salt: Peer review of the Office of Nuclear Waste Isolation's draft report on a multifactor test design to investigate uniform corrosion of low-carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Paddock, R.A.; Lerman, A.; Ditmars, J.D.; Macdonald, D.D.; Peerenboom, J.P.; Was, G.S.; Harrison, W.

    1987-01-01

    This report documents Argonne National Laboratory's review of an internal technical memorandum prepared by Battelle Memorial Institute's Office of Nuclear Waste Isolation (ONWI) entitled Multifactor Test Design to Investigate Uniform Corrosion of Low-Carbon Steel in a Nuclear Waste Salt Repository Environment. The several major areas of concern identified by peer review panelists are important to the credibility of the test design proposed in the memorandum and are to adequately addressed there. These areas of concern, along with specific recommendations to improve their treatment, are discussed in detail in Sec. 2 of this report. The twenty recommendations, which were abstracted from those discussions, are presented essentially in the order in which they are introduced in Sec. 2.

  2. Radioactive waste isolation in salt: Peer review of the Office of Nuclear Waste Isolation's draft report on a multifactor test design to investigate uniform corrosion of low-carbon steel

    International Nuclear Information System (INIS)

    Paddock, R.A.; Lerman, A.; Ditmars, J.D.; Macdonald, D.D.; Peerenboom, J.P.; Was, G.S.; Harrison, W.

    1987-01-01

    This report documents Argonne National Laboratory's review of an internal technical memorandum prepared by Battelle Memorial Institute's Office of Nuclear Waste Isolation (ONWI) entitled Multifactor Test Design to Investigate Uniform Corrosion of Low-Carbon Steel in a Nuclear Waste Salt Repository Environment. The several major areas of concern identified by peer review panelists are important to the credibility of the test design proposed in the memorandum and are to adequately addressed there. These areas of concern, along with specific recommendations to improve their treatment, are discussed in detail in Sec. 2 of this report. The twenty recommendations, which were abstracted from those discussions, are presented essentially in the order in which they are introduced in Sec. 2

  3. Snubber reduction

    International Nuclear Information System (INIS)

    Olson, D.E.; Singh, A.K.

    1986-01-01

    Many safety-related piping systems in nuclear power plants have been oversupported. Since snubbers make up a large percentage of the pipe supports or restraints used in a plant, a plant's snubber population is much larger than required to adequately restrain the piping. This has resulted in operating problems and unnecessary expenses for maintenance and inservice inspections (ISIs) of snubbers. This paper presents an overview of snubber reduction, including: the incentives for removing snubbers, a historical perspective on how piping became oversupported, why it is possible to remove snubbers, and the costs and benefits of doing so

  4. Higher-dimensional Bianchi type-VIh cosmologies

    Science.gov (United States)

    Lorenz-Petzold, D.

    1985-09-01

    The higher-dimensional perfect fluid equations of a generalization of the (1 + 3)-dimensional Bianchi type-VIh space-time are discussed. Bianchi type-V and Bianchi type-III space-times are also included as special cases. It is shown that the Chodos-Detweiler (1980) mechanism of cosmological dimensional-reduction is possible in these cases.

  5. Radon reduction

    International Nuclear Information System (INIS)

    Hamilton, M.A.

    1990-01-01

    During a radon gas screening program, elevated levels of radon gas were detected in homes on Mackinac Island, Mich. Six homes on foundations with crawl spaces were selected for a research project aimed at reducing radon gas concentrations, which ranged from 12.9 to 82.3 pCi/l. Using isolation and ventilation techniques, and variations thereof, radon concentrations were reduced to less than 1 pCi/l. This paper reports that these reductions were achieved using 3.5 mil cross laminated or 10 mil high density polyethylene plastic as a barrier without sealing to the foundation or support piers, solid and/or perforated plastic pipe and mechanical fans. Wind turbines were found to be ineffective at reducing concentrations to acceptable levels. Homeowners themselves installed all materials

  6. Extended supersymmetry in four-dimensional Euclidean space

    International Nuclear Information System (INIS)

    McKeon, D.G.C.; Sherry, T.N.

    2000-01-01

    Since the generators of the two SU(2) groups which comprise SO(4) are not Hermitian conjugates of each other, the simplest supersymmetry algebra in four-dimensional Euclidean space more closely resembles the N=2 than the N=1 supersymmetry algebra in four-dimensional Minkowski space. An extended supersymmetry algebra in four-dimensional Euclidean space is considered in this paper; its structure resembles that of N=4 supersymmetry in four-dimensional Minkowski space. The relationship of this algebra to the algebra found by dimensionally reducing the N=1 supersymmetry algebra in ten-dimensional Euclidean space to four-dimensional Euclidean space is examined. The dimensional reduction of N=1 super Yang-Mills theory in ten-dimensional Minkowski space to four-dimensional Euclidean space is also considered

  7. Significant reduction of normal tissue dose by proton radiotherapy compared with three-dimensional conformal or intensity-modulated radiation therapy in Stage I or Stage III non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Chang, Joe Y.; Zhang Xiaodong; Wang Xiaochun; Kang Yixiu; Riley, Beverly C.; Bilton, Stephen C.; Mohan, Radhe; Komaki, Ritsuko; Cox, James D.

    2006-01-01

    Purpose: To compare dose-volume histograms (DVH) in patients with non-small-cell lung cancer (NSCLC) treated by photon or proton radiotherapy. Methods and Materials: Dose-volume histograms were compared between photon, including three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and proton plans at doses of 66 Gy, 87.5 Gy in Stage I (n = 10) and 60-63 Gy, and 74 Gy in Stage III (n 15). Results: For Stage I, the mean total lung V5, V10, and V20 were 31.8%, 24.6%, and 15.8%, respectively, for photon 3D-CRT with 66 Gy, whereas they were 13.4%, 12.3%, and 10.9%, respectively, with proton with dose escalation to 87.5 cobalt Gray equivalents (CGE) (p = 0.002). For Stage III, the mean total lung V5, V10, and V20 were 54.1%, 46.9%, and 34.8%, respectively, for photon 3D-CRT with 63 Gy, whereas they were 39.7%, 36.6%, and 31.6%, respectively, for proton with dose escalation to 74 CGE (p = 0.002). In all cases, the doses to lung, spinal cord, heart, esophagus, and integral dose were lower with proton therapy even compared with IMRT. Conclusions: Proton treatment appears to reduce dose to normal tissues significantly, even with dose escalation, compared with standard-dose photon therapy, either 3D-CRT or IMRT

  8. Three-Dimensional Zn0.5Cd0.5S/Reduced Graphene Oxide Hybrid Aerogel: Facile Synthesis and the Visible-Light-Driven Photocatalytic Property for Reduction of Cr(VI in Water

    Directory of Open Access Journals (Sweden)

    Wei Xiao

    2016-01-01

    Full Text Available A series of three-dimensional ZnxCd1-xS/reduced graphene oxide (ZnxCd1-xS/RGO hybrid aerogels was successfully synthesized based on a one-pot hydrothermal approach, which were subsequently used as visible-light-driven photocatalysts for photoreduction of Cr(VI in water. Over 95% of Cr(VI was photoreduced by Zn0.5Cd0.5S/RGO aerogel material within 140 min, and such photocatalytic performance was superior to that of other ZnxCd1-xS/RGO aerogel materials (x≠0.5 and bare Zn0.5Cd0.5S. It was assumed that the enhanced photocatalytic activity of Zn0.5Cd0.5S/RGO aerogel was attributed to its high specific surface area and the preferable synergetic catalytic effect between Zn0.5Cd0.5S and RGO. Besides, Zn0.5Cd0.5S/RGO aerogel materials were robust and durable enough so that they could be reused several times with merely limited loss of photocatalytic activity. The chemical composition, phase, structure, and morphology of Zn0.5Cd0.5S/RGO aerogel material were carefully examined by a number of techniques like XRD, SEM, TEM, BET, Raman characterizations, and so on. It was found that Zn0.5Cd0.5S/RGO aerogel possessed hierarchically porous architecture with the specific surface area as high as 260.8 m2 g−1. The Zn0.5Cd0.5S component incorporated in Zn0.5Cd0.5S/RGO aerogel existed in the form of solid solution nanoparticles, which were uniformly distributed in the RGO matrix.

  9. Hidden symmetries in five-dimensional supergravity

    International Nuclear Information System (INIS)

    Poessel, M.

    2003-05-01

    This thesis is concerned with the study of hidden symmetries in supergravity, which play an important role in the present picture of supergravity and string theory. Concretely, the appearance of a hidden G 2(+2) /SO(4) symmetry is studied in the dimensional reduction of d=5, N=2 supergravity to three dimensions - a parallel model to the more famous E 8(+8) /SO(16) case in eleven-dimensional supergravity. Extending previous partial results for the bosonic part, I give a derivation that includes fermionic terms. This sheds new light on the appearance of the local hidden symmetry SO(4) in the reduction, and shows up an unusual feature which follows from an analysis of the R-symmetry associated with N=4 supergravity and of the supersymmetry variations, and which has no parallel in the eleven-dimensional case: The emergence of an additional SO(3) as part of the enhanced local symmetry, invisible in the dimensional reduction of the gravitino, and corresponding to the fact that, of the SO(4) used in the coset model, only the diagonal SO(3) is visible immediately upon dimensional reduction. The uncovering of the hidden symmetries proceeds via the construction of the proper coset gravity in three dimensions, and matching it with the Lagrangian obtained from the reduction. (orig.)

  10. Advances in data reduction of high-pressure x-ray powder diffraction data from two-dimensional detectors: a case study of schafarzikite (FeSb{sub 2}O{sub 4})

    Energy Technology Data Exchange (ETDEWEB)

    Hinrichsen, B [Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Dinnebier, R E [Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Rajiv, P [Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Hanfland, M [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP220, 38043 Grenoble Cedex (France); Grzechnik, A [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Technologia, Universidad del Pais Vasco, Apartado 644, E-48080 Bilbao (Spain); Jansen, M [Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany)

    2006-06-28

    Methods have been developed to facilitate the data analysis of multiple two-dimensional powder diffraction images. These include, among others, automatic detection and calibration of Debye-Scherrer ellipses using pattern recognition techniques, and signal filtering employing established statistical procedures like fractile statistics. All algorithms are implemented in the freely available program package Powder3D developed for the evaluation and graphical presentation of large powder diffraction data sets. As a case study, we report the pressure dependence of the crystal structure of iron antimony oxide FeSb{sub 2}O{sub 4} (p{<=}21 GPa, T = 298 K) using high-resolution angle dispersive x-ray powder diffraction. FeSb{sub 2}O{sub 4} shows two phase transitions in the measured pressure range. The crystal structures of all modifications consist of frameworks of Fe{sup 2+}O{sub 6} octahedra and irregular Sb{sup 3+}O{sub 4} polyhedra. At ambient conditions, FeSb{sub 2}O{sub 4} crystallizes in space group P4{sub 2}/mbc (phase I). Between p = 3.2 GPa and 4.1 GPa it exhibits a displacive second order phase transition to a structure of space group P 2{sub 1}/c (phase II, a = 5.7792(4) A, b = 8.3134(9) A, c = 8.4545(11) A, {beta} = 91.879(10){sup 0}, at p = 4.2 GPa). A second phase transition occurs between p = 6.4 GPa and 7.4 GPa to a structure of space group P4{sub 2}/m (phase III, a = 7.8498(4) A, c = 5.7452(5) A, at p = 10.5 GPa). A nonlinear compression behaviour over the entire pressure range is observed, which can be described by three Vinet equations in the ranges from p = 0.52 GPa to p 3.12 GPa, p = 4.2 GPa to p = 6.3 GPa and from p = 7.5 GPa to p = 19.8 GPa. The extrapolated bulk moduli of the high-pressure phases were determined to K{sub 0} = 49(2) GPa for phase I, K{sub 0} = 27(3) GPa for phase II and K{sub 0} = 45(2) GPa for phase III. The crystal structures of all phases are refined against x-ray powder data measured at several pressures between p = 0.52 GPa

  11. Model reduction of parametrized systems

    CERN Document Server

    Ohlberger, Mario; Patera, Anthony; Rozza, Gianluigi; Urban, Karsten

    2017-01-01

    The special volume offers a global guide to new concepts and approaches concerning the following topics: reduced basis methods, proper orthogonal decomposition, proper generalized decomposition, approximation theory related to model reduction, learning theory and compressed sensing, stochastic and high-dimensional problems, system-theoretic methods, nonlinear model reduction, reduction of coupled problems/multiphysics, optimization and optimal control, state estimation and control, reduced order models and domain decomposition methods, Krylov-subspace and interpolatory methods, and applications to real industrial and complex problems. The book represents the state of the art in the development of reduced order methods. It contains contributions from internationally respected experts, guaranteeing a wide range of expertise and topics. Further, it reflects an important effor t, carried out over the last 12 years, to build a growing research community in this field. Though not a textbook, some of the chapters ca...

  12. Infinite dimensional gauge structure of Kaluza-Klein theories II: D>5

    International Nuclear Information System (INIS)

    Aulakh, C.S.; Sahdev, D.

    1985-12-01

    We carry out the dimensional reduction of the pure gravity sector of Kaluza Klein theories without making truncations of any sort. This generalizes our previous result for the 5-dimensional case to 4+d(>1) dimensions. The effective 4-dimensional action has the structure of an infinite dimensional gauge theory

  13. Dimensional degression in AdSd

    International Nuclear Information System (INIS)

    Artsukevich, A. Yu.; Vasiliev, M. A.

    2009-01-01

    We analyze the pattern of fields in (d+1)-dimensional anti-de Sitter space in terms of those in d-dimensional anti-de Sitter space. The procedure, which is neither dimensional reduction nor dimensional compactification, is called dimensional degression. The analysis is performed group theoretically for all totally symmetric bosonic and fermionic representations of the anti-de Sitter algebra. The field-theoretical analysis is done for a massive scalar field in AdS d+d ' and massless spin-one-half, spin-one, and spin-two fields in AdS d+1 . The mass spectra of the resulting towers of fields in AdS d are found. For the scalar field case, the obtained results extend to the shadow sector those obtained by Metsaev [Nucl. Phys. B, Proc. Suppl. 102, 100 (2001)] by a different method.

  14. Model reduction for circuit simulation

    CERN Document Server

    Hinze, Michael; Maten, E Jan W Ter

    2011-01-01

    Simulation based on mathematical models plays a major role in computer aided design of integrated circuits (ICs). Decreasing structure sizes, increasing packing densities and driving frequencies require the use of refined mathematical models, and to take into account secondary, parasitic effects. This leads to very high dimensional problems which nowadays require simulation times too large for the short time-to-market demands in industry. Modern Model Order Reduction (MOR) techniques present a way out of this dilemma in providing surrogate models which keep the main characteristics of the devi

  15. Cohomological reduction of sigma models

    Energy Technology Data Exchange (ETDEWEB)

    Candu, Constantin; Mitev, Vladimir; Schomerus, Volker [DESY, Hamburg (Germany). Theory Group; Creutzig, Thomas [North Carolina Univ., Chapel Hill, NC (United States). Dept. of Physics and Astronomy

    2010-01-15

    This article studies some features of quantum field theories with internal supersymmetry, focusing mainly on 2-dimensional non-linear sigma models which take values in a coset superspace. It is discussed how BRST operators from the target space super- symmetry algebra can be used to identify subsectors which are often simpler than the original model and may allow for an explicit computation of correlation functions. After an extensive discussion of the general reduction scheme, we present a number of interesting examples, including symmetric superspaces G/G{sup Z{sub 2}} and coset superspaces of the form G/G{sup Z{sub 4}}. (orig.)

  16. Joint statistics of strongly correlated neurons via dimensionality reduction

    International Nuclear Information System (INIS)

    Deniz, Taşkın; Rotter, Stefan

    2017-01-01

    The relative timing of action potentials in neurons recorded from local cortical networks often shows a non-trivial dependence, which is then quantified by cross-correlation functions. Theoretical models emphasize that such spike train correlations are an inevitable consequence of two neurons being part of the same network and sharing some synaptic input. For non-linear neuron models, however, explicit correlation functions are difficult to compute analytically, and perturbative methods work only for weak shared input. In order to treat strong correlations, we suggest here an alternative non-perturbative method. Specifically, we study the case of two leaky integrate-and-fire neurons with strong shared input. Correlation functions derived from simulated spike trains fit our theoretical predictions very accurately. Using our method, we computed the non-linear correlation transfer as well as correlation functions that are asymmetric due to inhomogeneous intrinsic parameters or unequal input. (paper)

  17. Dimensionality Reduction in Big Data with Nonnegative Matrix Factorization

    Science.gov (United States)

    2017-06-20

    Multiplicative Update Rule(MUR), Projected Gradient Meth- ods (PrG), Block Principal Pivoting method(BlP), Fast Active-set-like method(AcS), Fast...16], one of the robust ensemble meth- ods , to classify the testing datasets. The proposed algorithm outperforms the other algorithms and PCA over all

  18. Finite-dimensional reductions of the discrete Toda chain

    International Nuclear Information System (INIS)

    Kazakova, T G

    2004-01-01

    The problem of construction of integrable boundary conditions for the discrete Toda chain is considered. The restricted chains for properly chosen closure conditions are reduced to the well-known discrete Painleve equations dP III , dP V , dP VI . Lax representations for these discrete Painleve equations are found

  19. Gauss-Bonnet actions and their dimensionally reduced descendants

    International Nuclear Information System (INIS)

    Mueller-Hoissen, F.

    1989-01-01

    A brief introduction to Gauss-Bonnet type generalizations of the Einstein-Hilbert gravity action in more than four dimensions is given and the structure of associated (effective) theories obtained by dimensional reduction is discussed. (author)

  20. Finding optimal exact reducts

    KAUST Repository

    AbouEisha, Hassan M.

    2014-01-01

    The problem of attribute reduction is an important problem related to feature selection and knowledge discovery. The problem of finding reducts with minimum cardinality is NP-hard. This paper suggests a new algorithm for finding exact reducts

  1. Two-dimensional errors

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This chapter addresses the extension of previous work in one-dimensional (linear) error theory to two-dimensional error analysis. The topics of the chapter include the definition of two-dimensional error, the probability ellipse, the probability circle, elliptical (circular) error evaluation, the application to position accuracy, and the use of control systems (points) in measurements

  2. Breast Reduction Surgery

    Science.gov (United States)

    ... considering breast reduction surgery, consult a board-certified plastic surgeon. It's important to understand what breast reduction surgery entails — including possible risks and complications — as ...

  3. Assessing Multiple Pathways for Achieving China’s National Emissions Reduction Target

    Directory of Open Access Journals (Sweden)

    Mingyue Wang

    2018-06-01

    Full Text Available In order to achieve China’s target of carbon intensity emissions reduction in 2030, there is a need to identify a scientific pathway and feasible strategies. In this study, we used stochastic frontier analysis method of energy efficiency, incorporating energy structure, economic structure, human capital, capital stock and potential energy efficiency to identify an efficient pathway for achieving emissions reduction target. We set up 96 scenarios including single factor scenarios and multi-factors combination scenarios for the simulation. The effects of each scenario on achieving the carbon intensity reduction target are then evaluated. It is found that: (1 Potential energy efficiency has the greatest contribution to the carbon intensity emissions reduction target; (2 they are unlikely to reach the 2030 carbon intensity reduction target of 60% by only optimizing a single factor; (3 in order to achieve the 2030 target, several aspects have to be adjusted: the fossil fuel ratio must be lower than 80%, and its average growth rate must be decreased by 2.2%; the service sector ratio in GDP must be higher than 58.3%, while the growth rate of non-service sectors must be lowered by 2.4%; and both human capital and capital stock must achieve and maintain a stable growth rate and a 1% increase annually in energy efficiency. Finally, the specific recommendations of this research were discussed, including constantly improved energy efficiency; the upgrading of China’s industrial structure must be accelerated; emissions reduction must be done at the root of energy sources; multi-level input mechanisms in overall levels of education and training to cultivate the human capital stock must be established; investment in emerging equipment and accelerate the closure of backward production capacity to accumulate capital stock.

  4. Dimensional cosmological principles

    International Nuclear Information System (INIS)

    Chi, L.K.

    1985-01-01

    The dimensional cosmological principles proposed by Wesson require that the density, pressure, and mass of cosmological models be functions of the dimensionless variables which are themselves combinations of the gravitational constant, the speed of light, and the spacetime coordinates. The space coordinate is not the comoving coordinate. In this paper, the dimensional cosmological principle and the dimensional perfect cosmological principle are reformulated by using the comoving coordinate. The dimensional perfect cosmological principle is further modified to allow the possibility that mass creation may occur. Self-similar spacetimes are found to be models obeying the new dimensional cosmological principle

  5. Hamiltonian reduction and supersymmetric mechanics with Dirac monopole

    International Nuclear Information System (INIS)

    Bellucci, Stefano; Nersessian, Armen; Yeranyan, Armen

    2006-01-01

    We apply the technique of Hamiltonian reduction for the construction of three-dimensional N=4 supersymmetric mechanics specified by the presence of a Dirac monopole. For this purpose we take the conventional N=4 supersymmetric mechanics on the four-dimensional conformally-flat spaces and perform its Hamiltonian reduction to three-dimensional system. We formulate the final system in the canonical coordinates, and present, in these terms, the explicit expressions of the Hamiltonian and supercharges. We show that, besides a magnetic monopole field, the resulting system is specified by the presence of a spin-orbit coupling term. A comparision with previous work is also carried out

  6. Infinitary Combinatory Reduction Systems: Normalising Reduction Strategies

    NARCIS (Netherlands)

    Ketema, J.; Simonsen, Jakob Grue

    2010-01-01

    We study normalising reduction strategies for infinitary Combinatory Reduction Systems (iCRSs). We prove that all fair, outermost-fair, and needed-fair strategies are normalising for orthogonal, fully-extended iCRSs. These facts properly generalise a number of results on normalising strategies in

  7. Reduction of Large Dynamical Systems by Minimization of Evolution Rate

    Science.gov (United States)

    Girimaji, Sharath S.

    1999-01-01

    Reduction of a large system of equations to a lower-dimensional system of similar dynamics is investigated. For dynamical systems with disparate timescales, a criterion for determining redundant dimensions and a general reduction method based on the minimization of evolution rate are proposed.

  8. Hidden symmetries in minimal five-dimensional supergravity

    International Nuclear Information System (INIS)

    Poessel, Markus; Silva, Sebastian

    2004-01-01

    We study the hidden symmetries arising in the dimensional reduction of d=5, N=2 supergravity to three dimensions. Extending previous partial results for the bosonic part, we give a derivation that includes fermionic terms, shedding light on the appearance of the local hidden symmetry SO(4) in the reduction

  9. Formulation of 11-dimensional supergravity in superspace

    International Nuclear Information System (INIS)

    Cremmer, E.; Ferrara, S.

    1980-01-01

    We formulate on-shell 11-dimensional supergravity in superspace and express its equations of motion in terms of purely geometrical quantities. All torsion and curvature components are solved in terms of a single superfield Wsub(rstu), totally antisymmetric in its (flat vector) indices. The dimensional reduction of this formulation is expected to be related to the superspace formulation of N = 8 extended supergravity and might explain the origin of the hidden (local) SU(8) and (global) E 7 symmetries present in this theory. (orig.)

  10. Reduction in language testing

    DEFF Research Database (Denmark)

    Dimova, Slobodanka; Jensen, Christian

    2013-01-01

    /video recorded speech samples and written reports produced by two experienced raters after testing. Our findings suggest that reduction or reduction-like pronunciation features are found in tested L2 speech, but whenever raters identify and comment on such reductions, they tend to assess reductions negatively......This study represents an initial exploration of raters' comments and actual realisations of form reductions in L2 test speech performances. Performances of three L2 speakers were selected as case studies and illustrations of how reductions are evaluated by the raters. The analysis is based on audio...

  11. The use of the bi-factor model to test the uni-dimensionality of a battery of reasoning tests.

    Science.gov (United States)

    Primi, Ricardo; Rocha da Silva, Marjorie Cristina; Rodrigues, Priscila; Muniz, Monalisa; Almeida, Leandro S

    2013-02-01

    The Battery of Reasoning Tests 5 (BPR-5) aims to assess the reasoning ability of individuals, using sub-tests with different formats and contents that require basic processes of inductive and deductive reasoning for their resolution. The BPR has three sequential forms: BPR-5i (for children from first to fifth grade), BPR-5 - Form A (for children from sixth to eighth grade) and BPR-5 - form B (for high school and undergraduate students). The present study analysed 412 questionnaires concerning BPR-5i, 603 questionnaires concerning BPR-5 - Form A and 1748 questionnaires concerning BPR-5 - Form B. The main goal was to test the uni-dimensionality of the battery and its tests in relation to items using the bi-factor model. Results suggest that the g factor loadings (extracted by the uni-dimensional model) do not change when the data is adjusted for a more flexible multi-factor model (bi-factor model). A general reasoning factor underlying different contents items is supported.

  12. System reduction for nanoscale IC design

    CERN Document Server

    2017-01-01

    This book describes the computational challenges posed by the progression toward nanoscale electronic devices and increasingly short design cycles in the microelectronics industry, and proposes methods of model reduction which facilitate circuit and device simulation for specific tasks in the design cycle. The goal is to develop and compare methods for system reduction in the design of high dimensional nanoelectronic ICs, and to test these methods in the practice of semiconductor development. Six chapters describe the challenges for numerical simulation of nanoelectronic circuits and suggest model reduction methods for constituting equations. These include linear and nonlinear differential equations tailored to circuit equations and drift diffusion equations for semiconductor devices. The performance of these methods is illustrated with numerical experiments using real-world data. Readers will benefit from an up-to-date overview of the latest model reduction methods in computational nanoelectronics.

  13. Four-dimensional Hall mechanics as a particle on CP3

    International Nuclear Information System (INIS)

    Bellucci, Stefano; Casteill, Pierre-Yves; Nersessian, Armen

    2003-01-01

    In order to establish an explicit connection between four-dimensional Hall effect on S 4 and six-dimensional Hall effect on CP 3 , we perform the Hamiltonian reduction of a particle moving on CP 3 in a constant magnetic field to the four-dimensional Hall mechanics (i.e., a-bar particle on S 4 in a SU(2) instanton field). This reduction corresponds to fixing the isospin of the latter system

  14. MCNP variance reduction overview

    International Nuclear Information System (INIS)

    Hendricks, J.S.; Booth, T.E.

    1985-01-01

    The MCNP code is rich in variance reduction features. Standard variance reduction methods found in most Monte Carlo codes are available as well as a number of methods unique to MCNP. We discuss the variance reduction features presently in MCNP as well as new ones under study for possible inclusion in future versions of the code

  15. Modern Reduction Methods

    CERN Document Server

    Andersson, Pher G

    2008-01-01

    With its comprehensive overview of modern reduction methods, this book features high quality contributions allowing readers to find reliable solutions quickly and easily. The monograph treats the reduction of carbonyles, alkenes, imines and alkynes, as well as reductive aminations and cross and heck couplings, before finishing off with sections on kinetic resolutions and hydrogenolysis. An indispensable lab companion for every chemist.

  16. Three-dimensional versus two-dimensional vision in laparoscopy

    DEFF Research Database (Denmark)

    Sørensen, Stine D; Savran, Mona Meral; Konge, Lars

    2016-01-01

    were cohort size and characteristics, skill trained or operation performed, instrument used, outcome measures, and conclusions. Two independent authors performed the search and data extraction. RESULTS: Three hundred and forty articles were screened for eligibility, and 31 RCTs were included...... through a two-dimensional (2D) projection on a monitor, which results in loss of depth perception. To counter this problem, 3D imaging for laparoscopy was developed. A systematic review of the literature was performed to assess the effect of 3D laparoscopy. METHODS: A systematic search of the literature...... in the review. Three trials were carried out in a clinical setting, and 28 trials used a simulated setting. Time was used as an outcome measure in all of the trials, and number of errors was used in 19 out of 31 trials. Twenty-two out of 31 trials (71 %) showed a reduction in performance time, and 12 out of 19...

  17. Lower dimensional gravity

    International Nuclear Information System (INIS)

    Brown, J.D.

    1988-01-01

    This book addresses the subject of gravity theories in two and three spacetime dimensions. The prevailing philosophy is that lower dimensional models of gravity provide a useful arena for developing new ideas and insights, which are applicable to four dimensional gravity. The first chapter consists of a comprehensive introduction to both two and three dimensional gravity, including a discussion of their basic structures. In the second chapter, the asymptotic structure of three dimensional Einstein gravity with a negative cosmological constant is analyzed. The third chapter contains a treatment of the effects of matter sources in classical two dimensional gravity. The fourth chapter gives a complete analysis of particle pair creation by electric and gravitational fields in two dimensions, and the resulting effect on the cosmological constant

  18. Three dimensional strained semiconductors

    Science.gov (United States)

    Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui

    2016-11-08

    In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

  19. Clustering high dimensional data

    DEFF Research Database (Denmark)

    Assent, Ira

    2012-01-01

    High-dimensional data, i.e., data described by a large number of attributes, pose specific challenges to clustering. The so-called ‘curse of dimensionality’, coined originally to describe the general increase in complexity of various computational problems as dimensionality increases, is known...... to render traditional clustering algorithms ineffective. The curse of dimensionality, among other effects, means that with increasing number of dimensions, a loss of meaningful differentiation between similar and dissimilar objects is observed. As high-dimensional objects appear almost alike, new approaches...... for clustering are required. Consequently, recent research has focused on developing techniques and clustering algorithms specifically for high-dimensional data. Still, open research issues remain. Clustering is a data mining task devoted to the automatic grouping of data based on mutual similarity. Each cluster...

  20. Big Data, Biostatistics and Complexity Reduction

    Czech Academy of Sciences Publication Activity Database

    Kalina, Jan

    2018-01-01

    Roč. 14, č. 2 (2018), s. 24-32 ISSN 1801-5603 R&D Projects: GA MZd(CZ) NV15-29835A Institutional support: RVO:67985807 Keywords : Biostatistics * Big data * Multivariate statistics * Dimensionality * Variable selection Subject RIV: IN - Informatics, Computer Science OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) https://www.ejbi.org/scholarly-articles/big-data-biostatistics-and-complexity-reduction.pdf

  1. Hamiltonian formalism of two-dimensional Vlasov kinetic equation.

    Science.gov (United States)

    Pavlov, Maxim V

    2014-12-08

    In this paper, the two-dimensional Benney system describing long wave propagation of a finite depth fluid motion and the multi-dimensional Russo-Smereka kinetic equation describing a bubbly flow are considered. The Hamiltonian approach established by J. Gibbons for the one-dimensional Vlasov kinetic equation is extended to a multi-dimensional case. A local Hamiltonian structure associated with the hydrodynamic lattice of moments derived by D. J. Benney is constructed. A relationship between this hydrodynamic lattice of moments and the two-dimensional Vlasov kinetic equation is found. In the two-dimensional case, a Hamiltonian hydrodynamic lattice for the Russo-Smereka kinetic model is constructed. Simple hydrodynamic reductions are presented.

  2. Super integrable four-dimensional autonomous mappings

    International Nuclear Information System (INIS)

    Capel, H W; Sahadevan, R; Rajakumar, S

    2007-01-01

    A systematic investigation of the complete integrability of a fourth-order autonomous difference equation of the type w(n + 4) = w(n)F(w(n + 1), w(n + 2), w(n + 3)) is presented. We identify seven distinct families of four-dimensional mappings which are super integrable and have three (independent) integrals via a duality relation as introduced in a recent paper by Quispel, Capel and Roberts (2005 J. Phys. A: Math. Gen. 38 3965-80). It is observed that these seven families can be related to the four-dimensional symplectic mappings with two integrals including all the four-dimensional periodic reductions of the integrable double-discrete modified Korteweg-deVries and sine-Gordon equations treated in an earlier paper by two of us (Capel and Sahadevan 2001 Physica A 289 86-106)

  3. Lung nodule detection performance in five observers on computed tomography (CT) with adaptive iterative dose reduction using three-dimensional processing (AIDR 3D) in a Japanese multicenter study: Comparison between ultra-low-dose CT and low-dose CT by receiver-operating characteristic analysis.

    Science.gov (United States)

    Nagatani, Yukihiro; Takahashi, Masashi; Murata, Kiyoshi; Ikeda, Mitsuru; Yamashiro, Tsuneo; Miyara, Tetsuhiro; Koyama, Hisanobu; Koyama, Mitsuhiro; Sato, Yukihisa; Moriya, Hiroshi; Noma, Satoshi; Tomiyama, Noriyuki; Ohno, Yoshiharu; Murayama, Sadayuki

    2015-07-01

    To compare lung nodule detection performance (LNDP) in computed tomography (CT) with adaptive iterative dose reduction using three dimensional processing (AIDR3D) between ultra-low dose CT (ULDCT) and low dose CT (LDCT). This was part of the Area-detector Computed Tomography for the Investigation of Thoracic Diseases (ACTIve) Study, a multicenter research project being conducted in Japan. Institutional Review Board approved this study and informed consent was obtained. Eighty-three subjects (body mass index, 23.3 ± 3.2) underwent chest CT at 6 institutions using identical scanners and protocols. In a single visit, each subject was scanned using different tube currents: 240, 120 and 20 mA (3.52, 1.74 and 0.29 mSv, respectively). Axial CT images with 2-mm thickness/increment were reconstructed using AIDR3D. Standard of reference (SOR) was determined based on CT images at 240 mA by consensus reading of 2 board-certificated radiologists as to the presence of lung nodules with the longest diameter (LD) of more than 3mm. Another 5 radiologists independently assessed and recorded presence/absence of lung nodules and their locations by continuously-distributed rating in CT images at 20 mA (ULDCT) and 120 mA (LDCT). Receiver-operating characteristic (ROC) analysis was used to evaluate LNDP of both methods in total and also in subgroups classified by LD (>4, 6 and 8 mm) and nodular characteristics (solid and ground glass nodules). For SOR, 161 solid and 60 ground glass nodules were identified. No significant difference in LNDP for entire solid nodules was demonstrated between both methods, as area under ROC curve (AUC) was 0.844 ± 0.017 in ULDCT and 0.876 ± 0.026 in LDCT (p=0.057). For ground glass nodules with LD 8mm or more, LNDP was similar between both methods, as AUC 0.899 ± 0.038 in ULDCT and 0.941 ± 0.030 in LDCT. (p=0.144). ULDCT using AIDR3D with an equivalent radiation dose to chest x-ray could have comparable LNDP to LDCT with AIDR3D except for smaller ground

  4. Workshop on multifactor aging mechanisms and models

    Science.gov (United States)

    Agarwal, V. K.

    1992-10-01

    There have been considerable efforts to understand the aging and failure mechanisms of insulation in electrical systems. However, progress has been slow because of the complex nature of the subject particularly when dealing with multiple stresses e.g. electrical, thermal, mechanical, radiation, humidity and other environmental factors. When an insulating material is exposed to just one stress factor e.g. electric field, one must devise test(s) which are not only economically efficient and practical but which take into account the nature of electric field (ac, dc and pulsed), duration and level or field strength, and field configurations. Any additional stress factor(s) make the matrix of measurements and the understanding of resulting degradation processes more complex, time consuming and expensive.

  5. Dynamic multifactor clustering of financial networks

    Science.gov (United States)

    Ross, Gordon J.

    2014-02-01

    We investigate the tendency for financial instruments to form clusters when there are multiple factors influencing the correlation structure. Specifically, we consider a stock portfolio which contains companies from different industrial sectors, located in several different countries. Both sector membership and geography combine to create a complex clustering structure where companies seem to first be divided based on sector, with geographical subclusters emerging within each industrial sector. We argue that standard techniques for detecting overlapping clusters and communities are not able to capture this type of structure and show how robust regression techniques can instead be used to remove the influence of both sector and geography from the correlation matrix separately. Our analysis reveals that prior to the 2008 financial crisis, companies did not tend to form clusters based on geography. This changed immediately following the crisis, with geography becoming a more important determinant of clustering structure.

  6. Organizational Deviance and Multi-Factor Leadership

    Science.gov (United States)

    Aksu, Ali

    2016-01-01

    Organizational deviant behaviors can be defined as behaviors that have deviated from standards and uncongenial to organization's expectations. When such behaviors have been thought to damage the organization, it can be said that reducing the deviation behaviors at minimum level is necessary for a healthy organization. The aim of this research is…

  7. Dimensional comparison theory.

    Science.gov (United States)

    Möller, Jens; Marsh, Herb W

    2013-07-01

    Although social comparison (Festinger, 1954) and temporal comparison (Albert, 1977) theories are well established, dimensional comparison is a largely neglected yet influential process in self-evaluation. Dimensional comparison entails a single individual comparing his or her ability in a (target) domain with his or her ability in a standard domain (e.g., "How good am I in math compared with English?"). This article reviews empirical findings from introspective, path-analytic, and experimental studies on dimensional comparisons, categorized into 3 groups according to whether they address the "why," "with what," or "with what effect" question. As the corresponding research shows, dimensional comparisons are made in everyday life situations. They impact on domain-specific self-evaluations of abilities in both domains: Dimensional comparisons reduce self-concept in the worse off domain and increase self-concept in the better off domain. The motivational basis for dimensional comparisons, their integration with recent social cognitive approaches, and the interdependence of dimensional, temporal, and social comparisons are discussed. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  8. Unitarity cuts and Reduction to master integrals in d dimensions for one-loop amplitudes

    CERN Document Server

    Anastasiou, C; Feng, B; Kunszt, Z; Mastrolia, Pierpaolo; Anastasiou, Charalampos; Britto, Ruth; Feng, Bo; Kunszt, Zoltan; Mastrolia, Pierpaolo

    2007-01-01

    We present an alternative reduction to master integrals for one-loop amplitudes using a unitarity cut method in arbitrary dimensions. We carry out the reduction in two steps. The first step is a pure four-dimensional cut-integration of tree amplitudes with a mass parameter, and the second step is applying dimensional shift identities to master integrals. This reduction is performed at the integrand level, so that coefficients can be read out algebraically.

  9. DataHigh: Graphical user interface for visualizing and interacting with high-dimensional neural activity

    OpenAIRE

    Cowley, Benjamin R.; Kaufman, Matthew T.; Churchland, Mark M.; Ryu, Stephen I.; Shenoy, Krishna V.; Yu, Byron M.

    2012-01-01

    The activity of tens to hundreds of neurons can be succinctly summarized by a smaller number of latent variables extracted using dimensionality reduction methods. These latent variables define a reduced-dimensional space in which we can study how population activity varies over time, across trials, and across experimental conditions. Ideally, we would like to visualize the population activity directly in the reduced-dimensional space, whose optimal dimensionality (as determined from the data)...

  10. Three dimensional canonical transformations

    International Nuclear Information System (INIS)

    Tegmen, A.

    2010-01-01

    A generic construction of canonical transformations is given in three-dimensional phase spaces on which Nambu bracket is imposed. First, the canonical transformations are defined as based on cannonade transformations. Second, it is shown that determination of the generating functions and the transformation itself for given generating function is possible by solving correspondent Pfaffian differential equations. Generating functions of type are introduced and all of them are listed. Infinitesimal canonical transformations are also discussed as the complementary subject. Finally, it is shown that decomposition of canonical transformations is also possible in three-dimensional phase spaces as in the usual two-dimensional ones.

  11. Gauged supergravities from M-theory reductions

    Science.gov (United States)

    Katmadas, Stefanos; Tomasiello, Alessandro

    2018-04-01

    In supergravity compactifications, there is in general no clear prescription on how to select a finite-dimensional family of metrics on the internal space, and a family of forms on which to expand the various potentials, such that the lower-dimensional effective theory is supersymmetric. We propose a finite-dimensional family of deformations for regular Sasaki-Einstein seven-manifolds M 7, relevant for M-theory compactifications down to four dimensions. It consists of integrable Cauchy-Riemann structures, corresponding to complex deformations of the Calabi-Yau cone M 8 over M 7. The non-harmonic forms we propose are the ones contained in one of the Kohn-Rossi cohomology groups, which is finite-dimensional and naturally controls the deformations of Cauchy-Riemann structures. The same family of deformations can be also described in terms of twisted cohomology of the base M 6, or in terms of Milnor cycles arising in deformations of M 8. Using existing results on SU(3) structure compactifications, we briefly discuss the reduction of M-theory on our class of deformed Sasaki-Einstein manifolds to four-dimensional gauged supergravity.

  12. Reduction - competitive tomorrow

    International Nuclear Information System (INIS)

    Worley, L.; Bargerstock, S.

    1995-01-01

    Inventory reduction is one of the few initiatives that represent significant cost-reduction potential that does not result in personnel reduction. Centerior Energy's Perry nuclear power plant has embarked on an aggressive program to reduce inventory while maintaining plant material availability. Material availability to the plant was above 98%, but at an unacceptable 1994 inventory book value of $47 million with inventory carrying costs calculated at 30% annually

  13. Process energy reduction

    International Nuclear Information System (INIS)

    Lowthian, W.E.

    1993-01-01

    Process Energy Reduction (PER) is a demand-side energy reduction approach which complements and often supplants other traditional energy reduction methods such as conservation and heat recovery. Because the application of PER is less obvious than the traditional methods, it takes some time to learn the steps as well as practice to become proficient in its use. However, the benefit is significant, often far outweighing the traditional energy reduction approaches. Furthermore, the method usually results in a better process having less waste and pollution along with improved yields, increased capacity, and lower operating costs

  14. Finding optimal exact reducts

    KAUST Repository

    AbouEisha, Hassan M.

    2014-01-01

    The problem of attribute reduction is an important problem related to feature selection and knowledge discovery. The problem of finding reducts with minimum cardinality is NP-hard. This paper suggests a new algorithm for finding exact reducts with minimum cardinality. This algorithm transforms the initial table to a decision table of a special kind, apply a set of simplification steps to this table, and use a dynamic programming algorithm to finish the construction of an optimal reduct. I present results of computer experiments for a collection of decision tables from UCIML Repository. For many of the experimented tables, the simplification steps solved the problem.

  15. Metallothermic reduction of molybdate

    International Nuclear Information System (INIS)

    Mukherjee, T.K.; Bose, D.K.

    1987-01-01

    This paper gives a brief account of the investigations conducted so far on metallothermic reduction of high grade molybdenite with particular emphasis on the work carried out in Bhabha Atomic Research Centre. Based on thermochemical considerations, the paper first introduces a number of metallic reductants suitable for use in metallothermic reduction of molybdenite. Aluminium, sodium and tin are found to be suitable reducing agents and very rightly they have found most applications in the research and development efforts on metallothermic reduction of molybdenite. The reduction with tin was conducted on fairly large scale both in vacuum and hydrogen atmosphere. The reaction was reported to be invariant depending mainly on the reduction temperature and a temperature of the order of 1250deg to 1300degC was required for good metal recovery. In comparison to tin, aluminothermic reduction of molybdenite was studied more extensively and it was conducted in closed bomb, vacuum and also in open atmosphere. In aluminothermic reduction, the influence of amount of reducing agent, amount of heat booster, preheating temperature and charging procedure on these metal yield was studied in detail. The reduction generally yielded massive molybdenum metal contaminated with aluminium as the major impurity element. Efforts were made to purify the reduced metal by arc melting, electron beam melting and molten salt electrorefining. 9 refs. (author)

  16. High-dimensional data in economics and their (robust) analysis

    Czech Academy of Sciences Publication Activity Database

    Kalina, Jan

    2017-01-01

    Roč. 12, č. 1 (2017), s. 171-183 ISSN 1452-4864 R&D Projects: GA ČR GA17-07384S Institutional support: RVO:67985556 Keywords : econometrics * high-dimensional data * dimensionality reduction * linear regression * classification analysis * robustness Subject RIV: BA - General Mathematics OBOR OECD: Business and management http://library.utia.cas.cz/separaty/2017/SI/kalina-0474076.pdf

  17. High-dimensional Data in Economics and their (Robust) Analysis

    Czech Academy of Sciences Publication Activity Database

    Kalina, Jan

    2017-01-01

    Roč. 12, č. 1 (2017), s. 171-183 ISSN 1452-4864 R&D Projects: GA ČR GA17-07384S Grant - others:GA ČR(CZ) GA13-01930S Institutional support: RVO:67985807 Keywords : econometrics * high-dimensional data * dimensionality reduction * linear regression * classification analysis * robustness Subject RIV: BB - Applied Statistics, Operational Research OBOR OECD: Statistics and probability

  18. Microbial reductive dehalogenation.

    Science.gov (United States)

    Mohn, W W; Tiedje, J M

    1992-01-01

    A wide variety of compounds can be biodegraded via reductive removal of halogen substituents. This process can degrade toxic pollutants, some of which are not known to be biodegraded by any other means. Reductive dehalogenation of aromatic compounds has been found primarily in undefined, syntrophic anaerobic communities. We discuss ecological and physiological principles which appear to be important in these communities and evaluate how widely applicable these principles are. Anaerobic communities that catalyze reductive dehalogenation appear to differ in many respects. A large number of pure cultures which catalyze reductive dehalogenation of aliphatic compounds are known, in contrast to only a few organisms which catalyze reductive dehalogenation of aromatic compounds. Desulfomonile tiedjei DCB-1 is an anaerobe which dehalogenates aromatic compounds and is physiologically and morphologically unusual in a number of respects, including the ability to exploit reductive dehalogenation for energy metabolism. When possible, we use D. tiedjei as a model to understand dehalogenating organisms in the above-mentioned undefined systems. Aerobes use reductive dehalogenation for substrates which are resistant to known mechanisms of oxidative attack. Reductive dehalogenation, especially of aliphatic compounds, has recently been found in cell-free systems. These systems give us an insight into how and why microorganisms catalyze this activity. In some cases transition metal complexes serve as catalysts, whereas in other cases, particularly with aromatic substrates, the catalysts appear to be enzymes. Images PMID:1406492

  19. Active3 noise reduction

    International Nuclear Information System (INIS)

    Holzfuss, J.

    1996-01-01

    Noise reduction is a problem being encountered in a variety of applications, such as environmental noise cancellation, signal recovery and separation. Passive noise reduction is done with the help of absorbers. Active noise reduction includes the transmission of phase inverted signals for the cancellation. This paper is about a threefold active approach to noise reduction. It includes the separation of a combined source, which consists of both a noise and a signal part. With the help of interaction with the source by scanning it and recording its response, modeling as a nonlinear dynamical system is achieved. The analysis includes phase space analysis and global radial basis functions as tools for the prediction used in a subsequent cancellation procedure. Examples are given which include noise reduction of speech. copyright 1996 American Institute of Physics

  20. Lung nodule detection performance in five observers on computed tomography (CT) with adaptive iterative dose reduction using three-dimensional processing (AIDR 3D) in a Japanese multicenter study: Comparison between ultra-low-dose CT and low-dose CT by receiver-operating characteristic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nagatani, Yukihiro, E-mail: yatsushi@belle.shiga-med.ac.jp [Department of Radiology, Shiga University of Medical Science, Otsu 520-2192, Shiga (Japan); Takahashi, Masashi; Murata, Kiyoshi [Department of Radiology, Shiga University of Medical Science, Otsu 520-2192, Shiga (Japan); Ikeda, Mitsuru [Department of Radiological and Medical Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673, Aichi (Japan); Yamashiro, Tsuneo [Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa (Japan); Miyara, Tetsuhiro [Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa (Japan); Department of Radiology, Okinawa Prefectural Yaeyama Hospital, Ishigaki 907-0022, Okinawa (Japan); Koyama, Hisanobu [Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo (Japan); Koyama, Mitsuhiro [Department of Radiology, Osaka Medical College, Takatsuki 569-8686, Osaka (Japan); Sato, Yukihisa [Department of Radiology, Osaka University Graduate School of Medicine, Suita 565-0871, Osaka (Japan); Department of Radiology, Osaka Medical Center of Cancer and Cardiovascular Diseases, Osaka 537-8511, Osaka (Japan); Moriya, Hiroshi [Department of Radiology, Ohara General Hospital, Fukushima 960-8611 (Japan); Noma, Satoshi [Department of Radiology, Tenri Hospital, Tenri 632-8552, Nara (Japan); Tomiyama, Noriyuki [Department of Radiology, Osaka University Graduate School of Medicine, Suita 565-0871, Osaka (Japan); Ohno, Yoshiharu [Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo (Japan); Murayama, Sadayuki [Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa (Japan)

    2015-07-15

    Highlights: • Using AIDR 3D, ULDCT showed comparable LND of solid nodules to LDCT. • Using AIDR 3D, LND of smaller GGN in ULDCT was inferior to that in LDCT. • Effective dose in ULDCT was about only twice of that in chest X-ray. • BMI values in study population were mostly in the normal range body habitus. - Abstract: Purpose: To compare lung nodule detection performance (LNDP) in computed tomography (CT) with adaptive iterative dose reduction using three dimensional processing (AIDR3D) between ultra-low dose CT (ULDCT) and low dose CT (LDCT). Materials and methods: This was part of the Area-detector Computed Tomography for the Investigation of Thoracic Diseases (ACTIve) Study, a multicenter research project being conducted in Japan. Institutional Review Board approved this study and informed consent was obtained. Eighty-three subjects (body mass index, 23.3 ± 3.2) underwent chest CT at 6 institutions using identical scanners and protocols. In a single visit, each subject was scanned using different tube currents: 240, 120 and 20 mA (3.52, 1.74 and 0.29 mSv, respectively). Axial CT images with 2-mm thickness/increment were reconstructed using AIDR3D. Standard of reference (SOR) was determined based on CT images at 240 mA by consensus reading of 2 board-certificated radiologists as to the presence of lung nodules with the longest diameter (LD) of more than 3 mm. Another 5 radiologists independently assessed and recorded presence/absence of lung nodules and their locations by continuously-distributed rating in CT images at 20 mA (ULDCT) and 120 mA (LDCT). Receiver-operating characteristic (ROC) analysis was used to evaluate LNDP of both methods in total and also in subgroups classified by LD (>4, 6 and 8 mm) and nodular characteristics (solid and ground glass nodules). Results: For SOR, 161 solid and 60 ground glass nodules were identified. No significant difference in LNDP for entire solid nodules was demonstrated between both methods, as area under ROC

  1. Euclidean D-branes and higher-dimensional gauge theory

    International Nuclear Information System (INIS)

    Acharya, B.S.; Figueroa-O'Farrill, J.M.; Spence, B.; O'Loughlin, M.

    1997-07-01

    We consider euclidean D-branes wrapping around manifolds of exceptional holonomy in dimensions seven and eight. The resulting theory on the D-brane-that is, the dimensional reduction of 10-dimensional supersymmetric Yang-Mills theory-is a cohomological field theory which describes the topology of the moduli space of instantons. The 7-dimensional theory is an N T =2 (or balanced) cohomological theory given by an action potential of Chern-Simons type. As a by-product of this method, we construct a related cohomological field theory which describes the monopole moduli space on a 7-manifold of G 2 holonomy. (author). 22 refs, 3 tabs

  2. Potential for waste reduction

    International Nuclear Information System (INIS)

    Warren, J.L.

    1990-01-01

    The author focuses on wastes considered hazardous under the Resource Conservation and Recovery Act. This chapter discusses wastes that are of interest as well as the factors affecting the quantity of waste considered available for waste reduction. Estimates are provided of the quantities of wastes generated. Estimates of the potential for waste reduction are meaningful only to the extent that one can understand the amount of waste actually being generated. Estimates of waste reduction potential are summarized from a variety of government and nongovernment sources

  3. Dimensional transition of the universe

    International Nuclear Information System (INIS)

    Terazawa, Hidezumi.

    1989-08-01

    In the extended n-dimensional Einstein theory of gravitation, where the spacetime dimension can be taken as a 'dynamical variable' which is determined by the 'Hamilton principle' of minimizing the extended Einstein-Hilbert action, it is suggested that our Universe of four-dimensional spacetime may encounter an astonishing dimensional transition into a new universe of three-dimensional or higher-than-four-dimensional spacetime. (author)

  4. Two-dimensional models

    International Nuclear Information System (INIS)

    Schroer, Bert; Freie Universitaet, Berlin

    2005-02-01

    It is not possible to compactly review the overwhelming literature on two-dimensional models in a meaningful way without a specific viewpoint; I have therefore tacitly added to the above title the words 'as theoretical laboratories for general quantum field theory'. I dedicate this contribution to the memory of J. A. Swieca with whom I have shared the passion of exploring 2-dimensional models for almost one decade. A shortened version of this article is intended as a contribution to the project 'Encyclopedia of mathematical physics' and comments, suggestions and critical remarks are welcome. (author)

  5. Three-dimensional neuroimaging

    International Nuclear Information System (INIS)

    Toga, A.W.

    1990-01-01

    This book reports on new neuroimaging technologies that are revolutionizing the study of the brain be enabling investigators to visualize its structure and entire pattern of functional activity in three dimensions. The book provides a theoretical and practical explanation of the new science of creating three-dimensional computer images of the brain. The coverage includes a review of the technology and methodology of neuroimaging, the instrumentation and procedures, issues of quantification, analytic protocols, and descriptions of neuroimaging systems. Examples are given to illustrate the use of three-dimensional enuroimaging to quantitate spatial measurements, perform analysis of autoradiographic and histological studies, and study the relationship between brain structure and function

  6. Four-dimensional anti-de Sitter toroidal black holes from a three-dimensional perspective: Full complexity

    International Nuclear Information System (INIS)

    Zanchin, Vilson T.; Kleber, Antares; Lemos, Jose P.S.

    2002-01-01

    The dimensional reduction of black hole solutions in four-dimensional (4D) general relativity is performed and new 3D black hole solutions are obtained. Considering a 4D spacetime with one spacelike Killing vector, it is possible to split the Einstein-Hilbert-Maxwell action with a cosmological term in terms of 3D quantities. Definitions of quasilocal mass and charges in 3D spacetimes are reviewed. The analysis is then particularized to the toroidal charged rotating anti-de Sitter black hole. The reinterpretation of the fields and charges in terms of a three-dimensional point of view is given in each case, and the causal structure analyzed

  7. A Corresponding Lie Algebra of a Reductive homogeneous Group and Its Applications

    International Nuclear Information System (INIS)

    Zhang Yu-Feng; Rui Wen-Juan; Wu Li-Xin

    2015-01-01

    With the help of a Lie algebra of a reductive homogeneous space G/K, where G is a Lie group and K is a resulting isotropy group, we introduce a Lax pair for which an expanding (2+1)-dimensional integrable hierarchy is obtained by applying the binormial-residue representation (BRR) method, whose Hamiltonian structure is derived from the trace identity for deducing (2+1)-dimensional integrable hierarchies, which was proposed by Tu, et al. We further consider some reductions of the expanding integrable hierarchy obtained in the paper. The first reduction is just right the (2+1)-dimensional AKNS hierarchy, the second-type reduction reveals an integrable coupling of the (2+1)-dimensional AKNS equation (also called the Davey-Stewartson hierarchy), a kind of (2+1)-dimensional Schrödinger equation, which was once reobtained by Tu, Feng and Zhang. It is interesting that a new (2+1)-dimensional integrable nonlinear coupled equation is generated from the reduction of the part of the (2+1)-dimensional integrable coupling, which is further reduced to the standard (2+1)-dimensional diffusion equation along with a parameter. In addition, the well-known (1+1)-dimensional AKNS hierarchy, the (1+1)-dimensional nonlinear Schrödinger equation are all special cases of the (2+1)-dimensional expanding integrable hierarchy. Finally, we discuss a few discrete difference equations of the diffusion equation whose stabilities are analyzed by making use of the von Neumann condition and the Fourier method. Some numerical solutions of a special stationary initial value problem of the (2+1)-dimensional diffusion equation are obtained and the resulting convergence and estimation formula are investigated. (paper)

  8. Breast reduction (mammoplasty) - slideshow

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/presentations/100189.htm Breast reduction (mammoplasty) - series—Indications To use the sharing features ... Lickstein, MD, FACS, specializing in cosmetic and reconstructive plastic surgery, Palm Beach Gardens, FL. Review provided by ...

  9. Medical Errors Reduction Initiative

    National Research Council Canada - National Science Library

    Mutter, Michael L

    2005-01-01

    The Valley Hospital of Ridgewood, New Jersey, is proposing to extend a limited but highly successful specimen management and medication administration medical errors reduction initiative on a hospital-wide basis...

  10. Microbial reductive dehalogenation.

    OpenAIRE

    Mohn, W W; Tiedje, J M

    1992-01-01

    A wide variety of compounds can be biodegraded via reductive removal of halogen substituents. This process can degrade toxic pollutants, some of which are not known to be biodegraded by any other means. Reductive dehalogenation of aromatic compounds has been found primarily in undefined, syntrophic anaerobic communities. We discuss ecological and physiological principles which appear to be important in these communities and evaluate how widely applicable these principles are. Anaerobic commun...

  11. Air Layer Drag Reduction

    Science.gov (United States)

    Ceccio, Steven; Elbing, Brian; Winkel, Eric; Dowling, David; Perlin, Marc

    2008-11-01

    A set of experiments have been conducted at the US Navy's Large Cavitation Channel to investigate skin-friction drag reduction with the injection of air into a high Reynolds number turbulent boundary layer. Testing was performed on a 12.9 m long flat-plate test model with the surface hydraulically smooth and fully rough at downstream-distance-based Reynolds numbers to 220 million and at speeds to 20 m/s. Local skin-friction, near-wall bulk void fraction, and near-wall bubble imaging were monitored along the length of the model. The instrument suite was used to access the requirements necessary to achieve air layer drag reduction (ALDR). Injection of air over a wide range of air fluxes showed that three drag reduction regimes exist when injecting air; (1) bubble drag reduction that has poor downstream persistence, (2) a transitional regime with a steep rise in drag reduction, and (3) ALDR regime where the drag reduction plateaus at 90% ± 10% over the entire model length with large void fractions in the near-wall region. These investigations revealed several requirements for ALDR including; sufficient volumetric air fluxes that increase approximately with the square of the free-stream speed, slightly higher air fluxes are needed when the surface tension is reduced, higher air fluxes are required for rough surfaces, and the formation of ALDR is sensitive to the inlet condition.

  12. De fire dimensioner

    DEFF Research Database (Denmark)

    Larsen, Mihail

    De fire dimensioner er en humanistisk håndbog beregnet især på studerende og vejledere inden for humaniora, men kan også læses af andre med interesse for, hvad humanistisk forskning er og kan. Den er blevet til over et langt livs engageret forskning, uddannelse og formidling på Roskilde Universitet...... og udgør på den måde også et bidrag til universitetets historie, som jeg var med til at grundlægge. De fire dimensioner sætter mennesket i centrum. Men det er et centrum, der peger ud over sig selv; et centrum, hvorfra verden anskues, erfares og forstås. Alle mennesker har en forhistorie og en...... fremtid, og udstrakt mellem disse punkter i tiden tænker og handler de i rummet. Den menneskelige tilværelse omfatter alle fire dimensioner. De fire dimensioner udgør derfor også et forsvar for en almen dannelse, der gennemtrænger og kommer kulturelt til udtryk i vores historie, viden, praksis og kunst....

  13. dimensional nonlinear evolution equations

    Indian Academy of Sciences (India)

    in real-life situations, it is important to find their exact solutions. Further, in ... But only little work is done on the high-dimensional equations. .... Similarly, to determine the values of d and q, we balance the linear term of the lowest order in eq.

  14. Two dimensional generalizations of the Newcomb equation

    International Nuclear Information System (INIS)

    Dewar, R.L.; Pletzer, A.

    1989-11-01

    The Bineau reduction to scalar form of the equation governing ideal, zero frequency linearized displacements from a hydromagnetic equilibrium possessing a continuous symmetry is performed in 'universal coordinates', applicable to both the toroidal and helical cases. The resulting generalized Newcomb equation (GNE) has in general a more complicated form than the corresponding one dimensional equation obtained by Newcomb in the case of circular cylindrical symmetry, but in this cylindrical case , the equation can be transformed to that of Newcomb. In the two dimensional case there is a transformation which leaves the form of the GNE invariant and simplifies the Frobenius expansion about a rational surface, especially in the limit of zero pressure gradient. The Frobenius expansions about a mode rational surface is developed and the connection with Hamiltonian transformation theory is shown. 17 refs

  15. Quantum transport in d -dimensional lattices

    International Nuclear Information System (INIS)

    Manzano, Daniel; Chuang, Chern; Cao, Jianshu

    2016-01-01

    We show that both fermionic and bosonic uniform d -dimensional lattices can be reduced to a set of independent one-dimensional chains. This reduction leads to the expression for ballistic energy fluxes in uniform fermionic and bosonic lattices. By the use of the Jordan–Wigner transformation we can extend our analysis to spin lattices, proving the coexistence of both ballistic and non-ballistic subspaces in any dimension and for any system size. We then relate the nature of transport to the number of excitations in the homogeneous spin lattice, indicating that a single excitation always propagates ballistically and that the non-ballistic behaviour of uniform spin lattices is a consequence of the interaction between different excitations. (paper)

  16. Extended inflation from higher dimensional theories

    International Nuclear Information System (INIS)

    Holman, R.; Kolb, E.W.; Vadas, S.L.; Wang, Yun.

    1990-04-01

    The possibility is considered that higher dimensional theories may, upon reduction to four dimensions, allow extended inflation to occur. Two separate models are analayzed. One is a very simple toy model consisting of higher dimensional gravity coupled to a scalar field whose potential allows for a first-order phase transition. The other is a more sophisticated model incorporating the effects of non-trivial field configurations (monopole, Casimir, and fermion bilinear condensate effects) that yield a non-trivial potential for the radius of the internal space. It was found that extended inflation does not occur in these models. It was also found that the bubble nucleation rate in these theories is time dependent unlike the case in the original version of extended inflation

  17. Extended inflation from higher-dimensional theories

    International Nuclear Information System (INIS)

    Holman, R.; Kolb, E.W.; Vadas, S.L.; Wang, Y.

    1991-01-01

    We consider the possibility that higher-dimensional theories may, upon reduction to four dimensions, allow extended inflation to occur. We analyze two separate models. One is a very simple toy model consisting of higher-dimensional gravity coupled to a scalar field whose potential allows for a first-order phase transition. The other is a more sophisticated model incorporating the effects of nontrivial field configurations (monopole, Casimir, and fermion bilinear condensate effects) that yield a nontrivial potential for the radius of the internal space. We find that extended inflation does not occur in these models. We also find that the bubble nucleation rate in these theories is time dependent unlike the case in the original version of extended inflation

  18. Incomplete Dirac reduction of constrained Hamiltonian systems

    Energy Technology Data Exchange (ETDEWEB)

    Chandre, C., E-mail: chandre@cpt.univ-mrs.fr

    2015-10-15

    First-class constraints constitute a potential obstacle to the computation of a Poisson bracket in Dirac’s theory of constrained Hamiltonian systems. Using the pseudoinverse instead of the inverse of the matrix defined by the Poisson brackets between the constraints, we show that a Dirac–Poisson bracket can be constructed, even if it corresponds to an incomplete reduction of the original Hamiltonian system. The uniqueness of Dirac brackets is discussed. The relevance of this procedure for infinite dimensional Hamiltonian systems is exemplified.

  19. A supersymmetric reduction on the three-sphere

    International Nuclear Information System (INIS)

    Deger, Nihat Sadik; Samtleben, Henning; Sarıoğlu, Özgür; Van den Bleeken, Dieter

    2015-01-01

    We present the embedding of three-dimensional SO(4)⋉R 6 gauged N=4 supergravity with quaternionic target space SO(4,4)/(SO(4)×SO(4)) into D=6, N=(1,0) supergravity coupled to a single chiral tensor multiplet through a consistent reduction on AdS 3 ×S 3

  20. Quantum theory without reduction

    International Nuclear Information System (INIS)

    Cini, Marcello; Levy-Leblond, J.-M.

    1990-01-01

    Quantum theory offers a strange, and perhaps unique, case in the history of science. Although research into its roots has provided important results in recent years, the debate goes on. Some theorists argue that quantum theory is weakened by the inclusion of the so called 'reduction of the state vector' in its foundations. Quantum Theory without Reduction presents arguments in favour of quantum theory as a consistent and complete theory without this reduction, and which is capable of explaining all known features of the measurement problem. This collection of invited contributions defines and explores different aspects of this issue, bringing an old debate into a new perspective, and leading to a more satisfying consensus about quantum theory. (author)

  1. Measuring mandibular ridge reduction

    International Nuclear Information System (INIS)

    Steen, W.H.A.

    1984-01-01

    This thesis investigates the mandibular reduction in height of complete denture wearers and overdenture wearers. To follow this reduction in the anterior region as well as in the lateral sections of the mandible, an accurate and reproducible measuring method is a prerequisite. A radiologic technique offers the best chance. A survey is given of the literature concerning the resorption process after the extraction of teeth. An oblique cephalometric radiographic technique is introduced as a promising method to measure mandibular ridge reduction. The reproducibility and the accuracy of the technique are determined. The reproducibility in the positioning of the mandible is improved by the introduction of a mandibular support which permits a precise repositioning of the edentulous jaw, even after long periods of investigation. (Auth.)

  2. Effective Hamiltonian for 2-dimensional arbitrary spin Ising model

    International Nuclear Information System (INIS)

    Sznajd, J.; Polska Akademia Nauk, Wroclaw. Inst. Niskich Temperatur i Badan Strukturalnych)

    1983-08-01

    The method of the reduction of the generalized arbitrary-spin 2-dimensional Ising model to spin-half Ising model is presented. The method is demonstrated in detail by calculating the effective interaction constants to the third order in cumulant expansion for the triangular spin-1 Ising model (the Blume-Emery-Griffiths model). (author)

  3. Chronoprojective invariance of the five-dimensional Schroedinger formalism

    International Nuclear Information System (INIS)

    Perrin, M.; Burdet, G.; Duval, C.

    1984-10-01

    Invariance properties of the five-dimensional Schroedinger formalism describing a quantum test particle in the Newton-Cartan theory of gravitation are studied. The geometry which underlies these invariance properties is presented as a reduction of the 0(5,2) conformal geometry various applications are given

  4. How to Reduce Dimensionality of Data: Robustness Point of View

    Czech Academy of Sciences Publication Activity Database

    Kalina, Jan; Rensová, D.

    2015-01-01

    Roč. 10, č. 1 (2015), s. 131-140 ISSN 1452-4864 R&D Projects: GA ČR GA13-17187S Institutional support: RVO:67985807 Keywords : data analysis * dimensionality reduction * robust statistics * principal component analysis * robust classification analysis Subject RIV: BB - Applied Statistics, Operational Research

  5. Finite-dimensional calculus

    International Nuclear Information System (INIS)

    Feinsilver, Philip; Schott, Rene

    2009-01-01

    We discuss topics related to finite-dimensional calculus in the context of finite-dimensional quantum mechanics. The truncated Heisenberg-Weyl algebra is called a TAA algebra after Tekin, Aydin and Arik who formulated it in terms of orthofermions. It is shown how to use a matrix approach to implement analytic representations of the Heisenberg-Weyl algebra in univariate and multivariate settings. We provide examples for the univariate case. Krawtchouk polynomials are presented in detail, including a review of Krawtchouk polynomials that illustrates some curious properties of the Heisenberg-Weyl algebra, as well as presenting an approach to computing Krawtchouk expansions. From a mathematical perspective, we are providing indications as to how to implement infinite terms Rota's 'finite operator calculus'.

  6. REDUCTIONS WITHOUT REGRET: SUMMARY

    Energy Technology Data Exchange (ETDEWEB)

    Swegle, J.; Tincher, D.

    2013-09-16

    This paper briefly summarizes the series in which we consider the possibilities for losing, or compromising, key capabilities of the U.S. nuclear force in the face of modernization and reductions. The first of the three papers takes an historical perspective, considering capabilities that were eliminated in past force reductions. The second paper is our attempt to define the needed capabilities looking forward in the context of the current framework for force modernization and the current picture of the evolving challenges of deterrence and assurance. The third paper then provides an example for each of our undesirable outcomes: the creation of roach motels, box canyons, and wrong turns.

  7. Dimensional analysis for engineers

    CERN Document Server

    Simon, Volker; Gomaa, Hassan

    2017-01-01

    This monograph provides the fundamentals of dimensional analysis and illustrates the method by numerous examples for a wide spectrum of applications in engineering. The book covers thoroughly the fundamental definitions and the Buckingham theorem, as well as the choice of the system of basic units. The authors also include a presentation of model theory and similarity solutions. The target audience primarily comprises researchers and practitioners but the book may also be suitable as a textbook at university level.

  8. Three Dimensional Dirac Semimetals

    Science.gov (United States)

    Zaheer, Saad

    2014-03-01

    Dirac points on the Fermi surface of two dimensional graphene are responsible for its unique electronic behavior. One can ask whether any three dimensional materials support similar pseudorelativistic physics in their bulk electronic spectra. This possibility has been investigated theoretically and is now supported by two successful experimental demonstrations reported during the last year. In this talk, I will summarize the various ways in which Dirac semimetals can be realized in three dimensions with primary focus on a specific theory developed on the basis of representations of crystal spacegroups. A three dimensional Dirac (Weyl) semimetal can appear in the presence (absence) of inversion symmetry by tuning parameters to the phase boundary separating a bulk insulating and a topological insulating phase. More generally, we find that specific rules governing crystal symmetry representations of electrons with spin lead to robust Dirac points at high symmetry points in the Brillouin zone. Combining these rules with microscopic considerations identifies six candidate Dirac semimetals. Another method towards engineering Dirac semimetals involves combining crystal symmetry and band inversion. Several candidate materials have been proposed utilizing this mechanism and one of the candidates has been successfully demonstrated as a Dirac semimetal in two independent experiments. Work carried out in collaboration with: Julia A. Steinberg, Steve M. Young, J.C.Y. Teo, C.L. Kane, E.J. Mele and Andrew M. Rappe.

  9. Symmetry Reductions of a 1.5-Layer Ocean Circulation Model

    International Nuclear Information System (INIS)

    Huang Fei; Lou Senyue

    2007-01-01

    The (2+1)-dimensional nonlinear 1.5-layer ocean circulation model without external wind stress forcing is analyzed by using the classical Lie group approach. Some Lie point symmetries and their corresponding two-dimensional reduction equations are obtained.

  10. hdm: High-dimensional metrics

    OpenAIRE

    Chernozhukov, Victor; Hansen, Christian; Spindler, Martin

    2016-01-01

    In this article the package High-dimensional Metrics (\\texttt{hdm}) is introduced. It is a collection of statistical methods for estimation and quantification of uncertainty in high-dimensional approximately sparse models. It focuses on providing confidence intervals and significance testing for (possibly many) low-dimensional subcomponents of the high-dimensional parameter vector. Efficient estimators and uniformly valid confidence intervals for regression coefficients on target variables (e...

  11. Three-dimensional ICT reconstruction

    International Nuclear Information System (INIS)

    Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

    2005-01-01

    The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context, qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

  12. Three-dimensional ICT reconstruction

    International Nuclear Information System (INIS)

    Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

    2004-01-01

    The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by order, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

  13. Dimensional control of die castings

    Science.gov (United States)

    Karve, Aniruddha Ajit

    The demand for net shape die castings, which require little or no machining, is steadily increasing. Stringent customer requirements are forcing die casters to deliver high quality castings in increasingly short lead times. Dimensional conformance to customer specifications is an inherent part of die casting quality. The dimensional attributes of a die casting are essentially dependent upon many factors--the quality of the die and the degree of control over the process variables being the two major sources of dimensional error in die castings. This study focused on investigating the nature and the causes of dimensional error in die castings. The two major components of dimensional error i.e., dimensional variability and die allowance were studied. The major effort of this study was to qualitatively and quantitatively study the effects of casting geometry and process variables on die casting dimensional variability and die allowance. This was accomplished by detailed dimensional data collection at production die casting sites. Robust feature characterization schemes were developed to describe complex casting geometry in quantitative terms. Empirical modeling was utilized to quantify the effects of the casting variables on dimensional variability and die allowance for die casting features. A number of casting geometry and process variables were found to affect dimensional variability in die castings. The dimensional variability was evaluated by comparisons with current published dimensional tolerance standards. The casting geometry was found to play a significant role in influencing the die allowance of the features measured. The predictive models developed for dimensional variability and die allowance were evaluated to test their effectiveness. Finally, the relative impact of all the components of dimensional error in die castings was put into perspective, and general guidelines for effective dimensional control in the die casting plant were laid out. The results of

  14. Adjunctive dental therapy via tooth plaque reduction and gingivitis treatment by blue light-emitting diodes tooth brushing

    Science.gov (United States)

    Genina, Elina A.; Titorenko, Vladimir A.; Belikov, Andrey V.; Bashkatov, Alexey N.; Tuchin, Valery V.

    2015-12-01

    The efficacy of blue light-emitting toothbrushes (B-LETBs) (405 to 420 nm, power density 2 mW/cm2) for reduction of dental plaques and gingival inflammation has been evaluated. Microbiological study has shown the multifactor therapeutic action of the B-LETBs on oral pathological microflora: in addition to partial mechanical removal of bacteria, photodynamic action suppresses them up to 97.5%. In the pilot clinical studies, subjects with mild to moderate gingivitis have been randomly divided into two groups: a treatment group that used the B-LETBs and a control group that used standard toothbrushes. Indices of plaque, gingival bleeding, and inflammation have been evaluated. A significant improvement of all dental indices in comparison with the baseline (by 59%, 66%, and 82% for plaque, gingival bleeding, and inflammation, respectively) has been found. The treatment group has demonstrated up to 50% improvement relative to the control group. We have proposed the B-LETBs to serve for prevention of gingivitis or as an alternative to conventional antibiotic treatment of this disease due to their effectiveness and the absence of drug side effects and bacterial resistance.

  15. A Comparison of Machine Learning Methods in a High-Dimensional Classification Problem

    OpenAIRE

    Zekić-Sušac, Marijana; Pfeifer, Sanja; Šarlija, Nataša

    2014-01-01

    Background: Large-dimensional data modelling often relies on variable reduction methods in the pre-processing and in the post-processing stage. However, such a reduction usually provides less information and yields a lower accuracy of the model. Objectives: The aim of this paper is to assess the high-dimensional classification problem of recognizing entrepreneurial intentions of students by machine learning methods. Methods/Approach: Four methods were tested: artificial neural networks, CART ...

  16. Wake Management Strategies for Reduction of Turbomachinery Fan Noise

    Science.gov (United States)

    Waitz, Ian A.

    1998-01-01

    The primary objective of our work was to evaluate and test several wake management schemes for the reduction of turbomachinery fan noise. Throughout the course of this work we relied on several tools. These include 1) Two-dimensional steady boundary-layer and wake analyses using MISES (a thin-shear layer Navier-Stokes code), 2) Two-dimensional unsteady wake-stator interaction simulations using UNSFLO, 3) Three-dimensional, steady Navier-Stokes rotor simulations using NEWT, 4) Internal blade passage design using quasi-one-dimensional passage flow models developed at MIT, 5) Acoustic modeling using LINSUB, 6) Acoustic modeling using VO72, 7) Experiments in a low-speed cascade wind-tunnel, and 8) ADP fan rig tests in the MIT Blowdown Compressor.

  17. One-Dimensionality and Whiteness

    Science.gov (United States)

    Calderon, Dolores

    2006-01-01

    This article is a theoretical discussion that links Marcuse's concept of one-dimensional society and the Great Refusal with critical race theory in order to achieve a more robust interrogation of whiteness. The author argues that in the context of the United States, the one-dimensionality that Marcuse condemns in "One-Dimensional Man" is best…

  18. One-dimensional structures behind twisted and untwisted superYang-Mills theory

    CERN Document Server

    Baulieu, Laurent

    2011-01-01

    We give a one-dimensional interpretation of the four-dimensional twisted N=1 superYang-Mills theory on a Kaehler manifold by performing an appropriate dimensional reduction. We prove the existence of a 6-generator superalgebra, which does not possess any invariant Lagrangian but contains two different subalgebras that determine the twisted and untwisted formulations of the N=1 superYang-Mills theory.

  19. One-dimensional structures behind twisted and untwisted super Yang-Mills theory

    Energy Technology Data Exchange (ETDEWEB)

    Baulieu, Laurent [CERN, Geneve (Switzerland). Theoretical Div.; Toppan, Francesco, E-mail: baulieu@lpthe.jussieu.f, E-mail: toppan@cbpf.b [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    2010-07-01

    We give a one-dimensional interpretation of the four-dimensional twisted N = 1 super Yang-Mills theory on a Kaehler manifold by performing an appropriate dimensional reduction. We prove the existence of a 6-generator superalgebra, which does not possess any invariant Lagrangian but contains two different subalgebras that determine the twisted and untwisted formulations of the N = 1 super Yang-Mills theory. (author)

  20. One-dimensional structures behind twisted and untwisted super Yang-Mills theory

    International Nuclear Information System (INIS)

    Baulieu, Laurent

    2010-01-01

    We give a one-dimensional interpretation of the four-dimensional twisted N = 1 super Yang-Mills theory on a Kaehler manifold by performing an appropriate dimensional reduction. We prove the existence of a 6-generator superalgebra, which does not possess any invariant Lagrangian but contains two different subalgebras that determine the twisted and untwisted formulations of the N = 1 super Yang-Mills theory. (author)

  1. The one-loop Green's functions of dimensionally reduced gauge theories

    International Nuclear Information System (INIS)

    Ketov, S.V.; Prager, Y.S.

    1988-01-01

    The dimensional regularization technique as well as that by dimensional reduction is applied to the calculation of the regularized one-loop Green's functions in dsub(o)-dimensional Yang-Mills theory with real massless scalars and spinors in arbitrary (real) representations of a gauge group G. As a particular example, the super-symmetrically regularized one-loop Green's functions of the N=4 supersymmetric Yang-Mills model are derived. (author). 17 refs

  2. Reduction of dinitrogen ligands

    International Nuclear Information System (INIS)

    Richards, R.L.

    1983-01-01

    Processes of dinitrogen ligand reduction in complexes of transition metals are considered. The basic character of the dinitrogen ligand is underlined. Data on X-ray photoelectronic spectroscopy and intensities of bands ν (N 2 ) in IR-spectra of nitrogen complexes are given. The mechanism of protonation of an edge dinitrogen ligand is discussed. Model systems and mechanism of nitrogenogenase are compared

  3. Infinitary Combinatory Reduction Systems

    DEFF Research Database (Denmark)

    Ketema, Jeroen; Simonsen, Jakob Grue

    2011-01-01

    We define infinitary Combinatory Reduction Systems (iCRSs), thus providing the first notion of infinitary higher-order rewriting. The systems defined are sufficiently general that ordinary infinitary term rewriting and infinitary ¿-calculus are special cases. Furthermore,we generalise a number...

  4. Galactorrhea after reduction mammaplasty

    NARCIS (Netherlands)

    Schuurman, A. H.; Assies, J.; van der Horst, C. M.; Bos, K. E.

    1993-01-01

    A case of extremely painful swelling of the breasts following a reduction mammaplasty is presented. There were no signs of an abscess or hematoma. A milky white fluid due to galactorrhea was evacuated at operation, and further galactorrhea was inhibited by medication. The pathogenesis of

  5. (MTT) dye reduction assay.

    African Journals Online (AJOL)

    to inhibit proliferation of HeLa cells was determined using the 3443- dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) dye reduction assay. Extracts from roots of Agathisanthemum bojeri, Synaptolepis kirkii and Zanha africana and the leaf extract of Physalis peruviana at a concentration of 10 pg/ml inhibited cell ...

  6. Streaming Reduction Circuit

    NARCIS (Netherlands)

    Gerards, Marco Egbertus Theodorus; Kuper, Jan; Kokkeler, Andre B.J.; Molenkamp, Egbert

    2009-01-01

    Reduction circuits are used to reduce rows of floating point values to single values. Binary floating point operators often have deep pipelines, which may cause hazards when many consecutive rows have to be reduced. We present an algorithm by which any number of consecutive rows of arbitrary lengths

  7. Dixon-Souriau equations from a 5-dimensional spinning particle in a Kaluza-Klein framework

    International Nuclear Information System (INIS)

    Cianfrani, F.; Milillo, I.; Montani, G.

    2007-01-01

    The dimensional reduction of Papapetrou equations is performed in a 5-dimensional Kaluza-Klein background and Dixon-Souriau results for the motion of a charged spinning body are obtained. The splitting provides an electric dipole moment, and, for elementary particles, the induced parity and time-reversal violations are explained

  8. Reduced order methods for modeling and computational reduction

    CERN Document Server

    Rozza, Gianluigi

    2014-01-01

    This monograph addresses the state of the art of reduced order methods for modeling and computational reduction of complex parametrized systems, governed by ordinary and/or partial differential equations, with a special emphasis on real time computing techniques and applications in computational mechanics, bioengineering and computer graphics.  Several topics are covered, including: design, optimization, and control theory in real-time with applications in engineering; data assimilation, geometry registration, and parameter estimation with special attention to real-time computing in biomedical engineering and computational physics; real-time visualization of physics-based simulations in computer science; the treatment of high-dimensional problems in state space, physical space, or parameter space; the interactions between different model reduction and dimensionality reduction approaches; the development of general error estimation frameworks which take into account both model and discretization effects. This...

  9. Discovering Hidden Controlling Parameters using Data Analytics and Dimensional Analysis

    Science.gov (United States)

    Del Rosario, Zachary; Lee, Minyong; Iaccarino, Gianluca

    2017-11-01

    Dimensional Analysis is a powerful tool, one which takes a priori information and produces important simplifications. However, if this a priori information - the list of relevant parameters - is missing a relevant quantity, then the conclusions from Dimensional Analysis will be incorrect. In this work, we present novel conclusions in Dimensional Analysis, which provide a means to detect this failure mode of missing or hidden parameters. These results are based on a restated form of the Buckingham Pi theorem that reveals a ridge function structure underlying all dimensionless physical laws. We leverage this structure by constructing a hypothesis test based on sufficient dimension reduction, allowing for an experimental data-driven detection of hidden parameters. Both theory and examples will be presented, using classical turbulent pipe flow as the working example. Keywords: experimental techniques, dimensional analysis, lurking variables, hidden parameters, buckingham pi, data analysis. First author supported by the NSF GRFP under Grant Number DGE-114747.

  10. Two-dimensional NMR spectrometry

    International Nuclear Information System (INIS)

    Farrar, T.C.

    1987-01-01

    This article is the second in a two-part series. In part one (ANALYTICAL CHEMISTRY, May 15) the authors discussed one-dimensional nuclear magnetic resonance (NMR) spectra and some relatively advanced nuclear spin gymnastics experiments that provide a capability for selective sensitivity enhancements. In this article and overview and some applications of two-dimensional NMR experiments are presented. These powerful experiments are important complements to the one-dimensional experiments. As in the more sophisticated one-dimensional experiments, the two-dimensional experiments involve three distinct time periods: a preparation period, t 0 ; an evolution period, t 1 ; and a detection period, t 2

  11. Mining High-Dimensional Data

    Science.gov (United States)

    Wang, Wei; Yang, Jiong

    With the rapid growth of computational biology and e-commerce applications, high-dimensional data becomes very common. Thus, mining high-dimensional data is an urgent problem of great practical importance. However, there are some unique challenges for mining data of high dimensions, including (1) the curse of dimensionality and more crucial (2) the meaningfulness of the similarity measure in the high dimension space. In this chapter, we present several state-of-art techniques for analyzing high-dimensional data, e.g., frequent pattern mining, clustering, and classification. We will discuss how these methods deal with the challenges of high dimensionality.

  12. Chemical Reduction Synthesis of Iron Aluminum Powders

    Science.gov (United States)

    Zurita-Méndez, N. N.; la Torre, G. Carbajal-De; Ballesteros-Almanza, L.; Villagómez-Galindo, M.; Sánchez-Castillo, A.; Espinosa-Medina, M. A.

    In this study, a chemical reduction synthesis method of iron aluminum (FeAl) nano-dimensional intermetallic powders is described. The process has two stages: a salt reduction and solvent evaporation by a heat treatment at 1100°C. The precursors of the synthesis are ferric chloride, aluminum foil chips, a mix of Toluene/THF in a 75/25 volume relationship, and concentrated hydrochloric acid as initiator of the reaction. The reaction time was 20 days, the product obtained was dried at 60 °C for 2 h and calcined at 400, 800, and 1100 °C for 4 h each. To characterize and confirm the obtained synthesis products, X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) techniques were used. The results of morphology and chemical characterization of nano-dimensional powders obtained showed a formation of agglomerated particles of a size range of approximately 150 nm to 1.0 μm. Composition of powders was identified as corundum (Al2O3), iron aluminide (FeAl3), and iron-aluminum oxides (Fe0. 53Al0. 47)2O3 phases. The oxide phases formation were associated with the reaction of atmospheric concentration-free oxygen during synthesis and sintering steps, reducing the concentration of the iron aluminum phase.

  13. Coset space dimension reduction of gauge theories

    International Nuclear Information System (INIS)

    Farakos, K.; Kapetanakis, D.; Koutsoumbas, G.; Zoupanos, G.

    1989-01-01

    A very interesting approach in the attempts to unify all the interactions is to consider that a unification takes place in higher than four dimensions. The most ambitious program based on the old Kaluza-Klein idea is not able to reproduce the low energy chiral nature of the weak interactions. A suggested way out was the introduction of Yang-Mills fields in the higher dimensional theory. From the particle physics point of view the most important question is how such a theory behaves in four dimensions and in particular in low energies. Therefore most of our efforts concern studies of the properties of an attractive scheme, the Coset-Space-Dimensional-Reduction (C.S.D.R.) scheme, which permits the study of the effective four dimensional theory coming from a gauge theory defined in higher dimensions. Here we summarize the C.S.D.R. procedure the main the rems which are obeyed and to present a realistic model which is the result of the model building efforts that take into account all the C.S.D.R. properties. (orig./HSI)

  14. Higher (odd dimensional quantum Hall effect and extended dimensional hierarchy

    Directory of Open Access Journals (Sweden)

    Kazuki Hasebe

    2017-07-01

    Full Text Available We demonstrate dimensional ladder of higher dimensional quantum Hall effects by exploiting quantum Hall effects on arbitrary odd dimensional spheres. Non-relativistic and relativistic Landau models are analyzed on S2k−1 in the SO(2k−1 monopole background. The total sub-band degeneracy of the odd dimensional lowest Landau level is shown to be equal to the winding number from the base-manifold S2k−1 to the one-dimension higher SO(2k gauge group. Based on the chiral Hopf maps, we clarify the underlying quantum Nambu geometry for odd dimensional quantum Hall effect and the resulting quantum geometry is naturally embedded also in one-dimension higher quantum geometry. An origin of such dimensional ladder connecting even and odd dimensional quantum Hall effects is illuminated from a viewpoint of the spectral flow of Atiyah–Patodi–Singer index theorem in differential topology. We also present a BF topological field theory as an effective field theory in which membranes with different dimensions undergo non-trivial linking in odd dimensional space. Finally, an extended version of the dimensional hierarchy for higher dimensional quantum Hall liquids is proposed, and its relationship to quantum anomaly and D-brane physics is discussed.

  15. Multi-dimensional imaging

    CERN Document Server

    Javidi, Bahram; Andres, Pedro

    2014-01-01

    Provides a broad overview of advanced multidimensional imaging systems with contributions from leading researchers in the field Multi-dimensional Imaging takes the reader from the introductory concepts through to the latest applications of these techniques. Split into 3 parts covering 3D image capture, processing, visualization and display, using 1) a Multi-View Approach and 2.) a Holographic Approach, followed by a 3rd part addressing other 3D systems approaches, applications and signal processing for advanced 3D imaging. This book describes recent developments, as well as the prospects and

  16. Dimensional analysis made simple

    International Nuclear Information System (INIS)

    Lira, Ignacio

    2013-01-01

    An inductive strategy is proposed for teaching dimensional analysis to second- or third-year students of physics, chemistry, or engineering. In this strategy, Buckingham's theorem is seen as a consequence and not as the starting point. In order to concentrate on the basics, the mathematics is kept as elementary as possible. Simple examples are suggested for classroom demonstrations of the power of the technique and others are put forward for homework or experimentation, but instructors are encouraged to produce examples of their own. (paper)

  17. Two-dimensional calculus

    CERN Document Server

    Osserman, Robert

    2011-01-01

    The basic component of several-variable calculus, two-dimensional calculus is vital to mastery of the broader field. This extensive treatment of the subject offers the advantage of a thorough integration of linear algebra and materials, which aids readers in the development of geometric intuition. An introductory chapter presents background information on vectors in the plane, plane curves, and functions of two variables. Subsequent chapters address differentiation, transformations, and integration. Each chapter concludes with problem sets, and answers to selected exercises appear at the end o

  18. Three-Dimensional Flows

    CERN Document Server

    Araujo, Vitor; Viana, Marcelo

    2010-01-01

    In this book, the authors present the elements of a general theory for flows on three-dimensional compact boundaryless manifolds, encompassing flows with equilibria accumulated by regular orbits. The book aims to provide a global perspective of this theory and make it easier for the reader to digest the growing literature on this subject. This is not the first book on the subject of dynamical systems, but there are distinct aspects which together make this book unique. Firstly, this book treats mostly continuous time dynamical systems, instead of its discrete counterpart, exhaustively treated

  19. Two dimensional simplicial paths

    International Nuclear Information System (INIS)

    Piso, M.I.

    1994-07-01

    Paths on the R 3 real Euclidean manifold are defined as 2-dimensional simplicial strips which are orbits of the action of a discrete one-parameter group. It is proven that there exists at least one embedding of R 3 in the free Z-module generated by S 2 (x 0 ). The speed is defined as the simplicial derivative of the path. If mass is attached to the simplex, the free Lagrangian is proportional to the width of the path. In the continuum limit, the relativistic form of the Lagrangian is recovered. (author). 7 refs

  20. Three dimensional system integration

    CERN Document Server

    Papanikolaou, Antonis; Radojcic, Riko

    2010-01-01

    Three-dimensional (3D) integrated circuit (IC) stacking is the next big step in electronic system integration. It enables packing more functionality, as well as integration of heterogeneous materials, devices, and signals, in the same space (volume). This results in consumer electronics (e.g., mobile, handheld devices) which can run more powerful applications, such as full-length movies and 3D games, with longer battery life. This technology is so promising that it is expected to be a mainstream technology a few years from now, less than 10-15 years from its original conception. To achieve thi

  1. High dimensional entanglement

    CSIR Research Space (South Africa)

    Mc

    2012-07-01

    Full Text Available stream_source_info McLaren_2012.pdf.txt stream_content_type text/plain stream_size 2190 Content-Encoding ISO-8859-1 stream_name McLaren_2012.pdf.txt Content-Type text/plain; charset=ISO-8859-1 High dimensional... entanglement M. McLAREN1,2, F.S. ROUX1 & A. FORBES1,2,3 1. CSIR National Laser Centre, PO Box 395, Pretoria 0001 2. School of Physics, University of the Stellenbosch, Private Bag X1, 7602, Matieland 3. School of Physics, University of Kwazulu...

  2. Dimensiones de la sostenibilidad

    OpenAIRE

    Usón Guardiola, Ezequiel

    2004-01-01

    Recientemente, las palabras sostenibilidad y desarrollo sostenible se han incorporado plenamente al vocabulario de muchos arquitectos, pero sólo en algunos casos se han convertido en una preocupación fundamental de su discurso arquitectónico. Es más, entre los arquitectos, tampoco se entiende muy bien la conexión que puede establecerse entre esta nueva sensibilidad y el proyecto arquitectónico, es decir, cómo pueden formalizarse y cuáles son las dimensiones de la sostenibilidad. Por ello y co...

  3. Dimensional crossover in fragmentation

    Science.gov (United States)

    Sotolongo-Costa, Oscar; Rodriguez, Arezky H.; Rodgers, G. J.

    2000-11-01

    Experiments in which thick clay plates and glass rods are fractured have revealed different behavior of fragment mass distribution function in the small and large fragment regions. In this paper we explain this behavior using non-extensive Tsallis statistics and show how the crossover between the two regions is caused by the change in the fragments’ dimensionality during the fracture process. We obtain a physical criterion for the position of this crossover and an expression for the change in the power-law exponent between the small and large fragment regions. These predictions are in good agreement with the experiments on thick clay plates.

  4. Spontaneous wave packet reduction

    International Nuclear Information System (INIS)

    Ghirardi, G.C.

    1994-06-01

    There are taken into account the main conceptual difficulties met by standard quantum mechanics in dealing with physical processes involving macroscopic system. It is stressed how J.A.Wheeler's remarks and lucid analysis have been relevant to pinpoint and to bring to its extreme consequences the puzzling aspects of quantum phenomena. It is shown how the recently proposed models of spontaneous dynamical reduction represent a consistent way to overcome the conceptual difficulties of the standard theory. Obviously, many nontrivial problems remain open, the first and more relevant one being that of generalizing the model theories considered to the relativistic case. This is the challenge of the dynamical reduction program. 43 refs, 2 figs

  5. BP volume reduction equipment

    International Nuclear Information System (INIS)

    Kitamura, Yoshinori; Muroo, Yoji; Hamanaka, Isao

    2003-01-01

    A new type of burnable poison (BP) volume reduction system is currently being developed. Many BP rods, a subcomponent of spent fuel assemblies are discharged from nuclear power reactors. This new system reduces the overall volume of BP rods. The main system consists of BP rod cutting equipment, equipment for the recovery of BP cut pieces, and special transport equipment for the cut rods. The equipment is all operated by hydraulic press cylinders in water to reduce operator exposure to radioactivity. (author)

  6. Anaerobic azo dye reduction

    OpenAIRE

    Zee, van der, F.P.

    2002-01-01

    Azo dyes, aromatic moieties linked together by azo (-N=N-) chromophores, represent the largest class of dyes used in textile-processing and other industries. The release of these compounds into the environment is undesirable, not only because of their colour, but also because many azo dyes and their breakdown products are toxic and/or mutagenic to life. To remove azo dyes from wastewater, a biological treatment strategy based on anaerobic reduction of the azo dye...

  7. Global sensitivity analysis by polynomial dimensional decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Sharif, E-mail: rahman@engineering.uiowa.ed [College of Engineering, The University of Iowa, Iowa City, IA 52242 (United States)

    2011-07-15

    This paper presents a polynomial dimensional decomposition (PDD) method for global sensitivity analysis of stochastic systems subject to independent random input following arbitrary probability distributions. The method involves Fourier-polynomial expansions of lower-variate component functions of a stochastic response by measure-consistent orthonormal polynomial bases, analytical formulae for calculating the global sensitivity indices in terms of the expansion coefficients, and dimension-reduction integration for estimating the expansion coefficients. Due to identical dimensional structures of PDD and analysis-of-variance decomposition, the proposed method facilitates simple and direct calculation of the global sensitivity indices. Numerical results of the global sensitivity indices computed for smooth systems reveal significantly higher convergence rates of the PDD approximation than those from existing methods, including polynomial chaos expansion, random balance design, state-dependent parameter, improved Sobol's method, and sampling-based methods. However, for non-smooth functions, the convergence properties of the PDD solution deteriorate to a great extent, warranting further improvements. The computational complexity of the PDD method is polynomial, as opposed to exponential, thereby alleviating the curse of dimensionality to some extent.

  8. Thermochemical nitrate reduction

    International Nuclear Information System (INIS)

    Cox, J.L.; Lilga, M.A.; Hallen, R.T.

    1992-09-01

    A series of preliminary experiments was conducted directed at thermochemically converting nitrate to nitrogen and water. Nitrates are a major constituent of the waste stored in the underground tanks on the Hanford Site, and the characteristics and effects of nitrate compounds on stabilization techniques must be considered before permanent disposal operations begin. For the thermochemical reduction experiments, six reducing agents (ammonia, formate, urea, glucose, methane, and hydrogen) were mixed separately with ∼3 wt% NO 3 - solutions in a buffered aqueous solution at high pH (13); ammonia and formate were also mixed at low pH (4). Reactions were conducted in an aqueous solution in a batch reactor at temperatures of 200 degrees C to 350 degrees C and pressures of 600 to 2800 psig. Both gas and liquid samples were analyzed. The specific components analyzed were nitrate, nitrite, nitrous oxide, nitrogen, and ammonia. Results of experimental runs showed the following order of nitrate reduction of the six reducing agents in basic solution: formate > glucose > urea > hydrogen > ammonia ∼ methane. Airnmonia was more effective under acidic conditions than basic conditions. Formate was also effective under acidic conditions. A more thorough, fundamental study appears warranted to provide additional data on the mechanism of nitrate reduction. Furthermore, an expanded data base and engineering feasibility study could be used to evaluate conversion conditions for promising reducing agents in more detail and identify new reducing agents with improved performance characteristics

  9. New results for algebraic tensor reduction of Feynman integrals

    Energy Technology Data Exchange (ETDEWEB)

    Fleischer, Jochem [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Riemann, Tord [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Yundin, Valery [Copenhagen Univ. (Denmark). Niels Bohr International Academy and Discovery Center

    2012-02-15

    We report on some recent developments in algebraic tensor reduction of one-loop Feynman integrals. For 5-point functions, an efficient tensor reduction was worked out recently and is now available as numerical C++ package, PJFry, covering tensor ranks until five. It is free of inverse 5- point Gram determinants and inverse small 4-point Gram determinants are treated by expansions in higher-dimensional 3-point functions. By exploiting sums over signed minors, weighted with scalar products of chords (or, equivalently, external momenta), extremely efficient expressions for tensor integrals contracted with external momenta were derived. The evaluation of 7-point functions is discussed. In the present approach one needs for the reductions a (d +2)-dimensional scalar 5-point function in addition to the usual scalar basis of 1- to 4-point functions in the generic dimension d=4-2{epsilon}. When exploiting the four-dimensionality of the kinematics, this basis is sufficient. We indicate how the (d+2)-dimensional 5-point function can be evaluated. (orig.)

  10. New results for algebraic tensor reduction of Feynman integrals

    International Nuclear Information System (INIS)

    Fleischer, Jochem; Yundin, Valery

    2012-02-01

    We report on some recent developments in algebraic tensor reduction of one-loop Feynman integrals. For 5-point functions, an efficient tensor reduction was worked out recently and is now available as numerical C++ package, PJFry, covering tensor ranks until five. It is free of inverse 5- point Gram determinants and inverse small 4-point Gram determinants are treated by expansions in higher-dimensional 3-point functions. By exploiting sums over signed minors, weighted with scalar products of chords (or, equivalently, external momenta), extremely efficient expressions for tensor integrals contracted with external momenta were derived. The evaluation of 7-point functions is discussed. In the present approach one needs for the reductions a (d +2)-dimensional scalar 5-point function in addition to the usual scalar basis of 1- to 4-point functions in the generic dimension d=4-2ε. When exploiting the four-dimensionality of the kinematics, this basis is sufficient. We indicate how the (d+2)-dimensional 5-point function can be evaluated. (orig.)

  11. Higher-order gravity in higher dimensions: geometrical origins of four-dimensional cosmology?

    Energy Technology Data Exchange (ETDEWEB)

    Troisi, Antonio [Universita degli Studi di Salerno, Dipartimento di Fisica ' ' E.R. Caianiello' ' , Salerno (Italy)

    2017-03-15

    Determining the cosmological field equations is still very much debated and led to a wide discussion around different theoretical proposals. A suitable conceptual scheme could be represented by gravity models that naturally generalize Einstein theory like higher-order gravity theories and higher-dimensional ones. Both of these two different approaches allow one to define, at the effective level, Einstein field equations equipped with source-like energy-momentum tensors of geometrical origin. In this paper, the possibility is discussed to develop a five-dimensional fourth-order gravity model whose lower-dimensional reduction could provide an interpretation of cosmological four-dimensional matter-energy components. We describe the basic concepts of the model, the complete field equations formalism and the 5-D to 4-D reduction procedure. Five-dimensional f(R) field equations turn out to be equivalent, on the four-dimensional hypersurfaces orthogonal to the extra coordinate, to an Einstein-like cosmological model with three matter-energy tensors related with higher derivative and higher-dimensional counter-terms. By considering the gravity model with f(R) = f{sub 0}R{sup n} the possibility is investigated to obtain five-dimensional power law solutions. The effective four-dimensional picture and the behaviour of the geometrically induced sources are finally outlined in correspondence to simple cases of such higher-dimensional solutions. (orig.)

  12. Mapping Earth's electromagnetic dimensionality

    Science.gov (United States)

    Love, J. J.; Kelbert, A.; Bedrosian, P.

    2017-12-01

    The form of a magnetotelluric impedance tensor, obtained for a given geographic site through simultaneous measurement of geomagnetic and geoelectric field variation, is affected by electrical conductivity structure beneath the measurement site. Building on existing methods for characterizing the symmetry of magnetotelluric impedance tensors, a simple scalar measure is developed for measuring the (frequency dependent) proportion of the impedance tensor that is not just a one-dimensional (1D) function of depth ("non-1D-ness"). These measures are applied to nearly 1000 impedance tensors obtained during magnetotelluric surveys, those for the continental United States and obtained principally through the National Science Foundation's EarthScope project. Across geomagnetic/geoelectric variational periods ranging from 30 s to 3,000 s, corresponding to crustal and upper mantle depths, it is shown that local Earth structure is very often not simply 1D-depth-dependent - often less than 50% of magnetotelluric impedance is 1D. For selected variational frequencies, non-1D-ness is mapped and the relationship between electromagnetic dimensionality and known geological and tectonic structures is discussed. The importance of using realistic surface impedances to accurately evaluate magnetic-storm geoelectric hazards is emphasized.

  13. Two-dimensional ferroelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Blinov, L M; Fridkin, Vladimir M; Palto, Sergei P [A.V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow, Russian Federaion (Russian Federation); Bune, A V; Dowben, P A; Ducharme, Stephen [Department of Physics and Astronomy, Behlen Laboratory of Physics, Center for Materials Research and Analysis, University of Nebraska-Linkoln, Linkoln, NE (United States)

    2000-03-31

    The investigation of the finite-size effect in ferroelectric crystals and films has been limited by the experimental conditions. The smallest demonstrated ferroelectric crystals had a diameter of {approx}200 A and the thinnest ferroelectric films were {approx}200 A thick, macroscopic sizes on an atomic scale. Langmuir-Blodgett deposition of films one monolayer at a time has produced high quality ferroelectric films as thin as 10 A, made from polyvinylidene fluoride and its copolymers. These ultrathin films permitted the ultimate investigation of finite-size effects on the atomic thickness scale. Langmuir-Blodgett films also revealed the fundamental two-dimensional character of ferroelectricity in these materials by demonstrating that there is no so-called critical thickness; films as thin as two monolayers (1 nm) are ferroelectric, with a transition temperature near that of the bulk material. The films exhibit all the main properties of ferroelectricity with a first-order ferroelectric-paraelectric phase transition: polarization hysteresis (switching); the jump in spontaneous polarization at the phase transition temperature; thermal hysteresis in the polarization; the increase in the transition temperature with applied field; double hysteresis above the phase transition temperature; and the existence of the ferroelectric critical point. The films also exhibit a new phase transition associated with the two-dimensional layers. (reviews of topical problems)

  14. Reduced basis ANOVA methods for partial differential equations with high-dimensional random inputs

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Qifeng, E-mail: liaoqf@shanghaitech.edu.cn [School of Information Science and Technology, ShanghaiTech University, Shanghai 200031 (China); Lin, Guang, E-mail: guanglin@purdue.edu [Department of Mathematics & School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 (United States)

    2016-07-15

    In this paper we present a reduced basis ANOVA approach for partial deferential equations (PDEs) with random inputs. The ANOVA method combined with stochastic collocation methods provides model reduction in high-dimensional parameter space through decomposing high-dimensional inputs into unions of low-dimensional inputs. In this work, to further reduce the computational cost, we investigate spatial low-rank structures in the ANOVA-collocation method, and develop efficient spatial model reduction techniques using hierarchically generated reduced bases. We present a general mathematical framework of the methodology, validate its accuracy and demonstrate its efficiency with numerical experiments.

  15. Kaluza-Klein cosmology from five-dimensional Lovelock-Cartan theory

    Science.gov (United States)

    Castillo-Felisola, Oscar; Corral, Cristóbal; del Pino, Simón; Ramírez, Francisca

    2016-12-01

    We study the Kaluza-Klein dimensional reduction of the Lovelock-Cartan theory in five-dimensional spacetime, with a compact dimension of S1 topology. We find cosmological solutions of the Friedmann-Robertson-Walker class in the reduced spacetime. The torsion and the fields arising from the dimensional reduction induce a nonvanishing energy-momentum tensor in four dimensions. We find solutions describing expanding, contracting, and bouncing universes. The model shows a dynamical compactification of the extra dimension in some regions of the parameter space.

  16. Vietnam; Poverty Reduction Strategy Paper

    OpenAIRE

    International Monetary Fund

    2004-01-01

    This paper assesses the Poverty Reduction Strategy Paper of Vietnam, known as the Comprehensive Poverty Reduction and Growth Strategy (CPRGS). It is an action program to achieve economic growth and poverty reduction objectives. This paper reviews the objectives and tasks of socio-economic development and poverty reduction. The government of Vietnam takes poverty reduction as a cutting-through objective in the process of country socio-economic development and declares its commitment to impleme...

  17. ONE-DIMENSIONAL AND TWO-DIMENSIONAL LEADERSHIP STYLES

    Directory of Open Access Journals (Sweden)

    Nikola Stefanović

    2007-06-01

    Full Text Available In order to motivate their group members to perform certain tasks, leaders use different leadership styles. These styles are based on leaders' backgrounds, knowledge, values, experiences, and expectations. The one-dimensional styles, used by many world leaders, are autocratic and democratic styles. These styles lie on the two opposite sides of the leadership spectrum. In order to precisely define the leadership styles on the spectrum between the autocratic leadership style and the democratic leadership style, leadership theory researchers use two dimensional matrices. The two-dimensional matrices define leadership styles on the basis of different parameters. By using these parameters, one can identify two-dimensional styles.

  18. Three-dimensional laparoscopy vs 2-dimensional laparoscopy with high-definition technology for abdominal surgery

    DEFF Research Database (Denmark)

    Fergo, Charlotte; Burcharth, Jakob; Pommergaard, Hans-Christian

    2017-01-01

    BACKGROUND: This systematic review investigates newer generation 3-dimensional (3D) laparoscopy vs 2-dimensional (2D) laparoscopy in terms of error rating, performance time, and subjective assessment as early comparisons have shown contradictory results due to technological shortcomings. DATA...... Central Register of Controlled Trials database. CONCLUSIONS: Of 643 articles, 13 RCTs were included, of which 2 were clinical trials. Nine of 13 trials (69%) and 10 of 13 trials (77%) found a significant reduction in performance time and error, respectively, with the use of 3D-laparoscopy. Overall, 3D......-laparoscopy was found to be superior or equal to 2D-laparoscopy. All trials featuring subjective evaluation found a superiority of 3D-laparoscopy. More clinical RCTs are still awaited for the convincing results to be reproduced....

  19. Giant Andreev backscattering and reentrant resistance in a 2- dimensional electron gas coupled to superconductors

    NARCIS (Netherlands)

    den Hartog, Sander; Wees, B.J. van; Nazarov, Yu.V.; Klapwijk, T.M.; Borghs, G.

    1998-01-01

    We have investigated the superconducting-phase modulated reduction in the resistance of a ballistic quantum point contact (QPC) connected via a disordered 2-dimensional electron gas (2DEG) to superconductors. We show that this reduction is caused by coherent Andreev back scattering of holes through

  20. Understanding decay resistance, dimensional stability and strength changes in heat treated and acetylated wood

    Science.gov (United States)

    Roger M. Rowell; Rebecca E. Ibach; James McSweeny; Thomas Nilsson

    2009-01-01

    Reductions in hygroscopicity, increased dimensional stability and decay resistance of heat-treated wood depend on decomposition of a large portion of the hemicelluloses in the wood cell wall. In theory, these hemicelluloses are converted to small organic molecules, water and volatile furan-type intermediates that can polymerize in the cell wall. Reductions in...

  1. Exact solutions for the (2+1)-dimensional Boiti-Leon-Pempielli system

    International Nuclear Information System (INIS)

    Hu, Y H; Zheng, C L

    2008-01-01

    The object reduction approach is applied to the (2+1)-dimensional Boiti-Leon-Pempielli system using a special conditional similarity reduction. Abundant exact solutions of this system, including the hyperboloid function solutions, the trigonometric function solutions and a rational function solution, are obtained

  2. Discrete Routh reduction

    International Nuclear Information System (INIS)

    Jalnapurkar, Sameer M; Leok, Melvin; Marsden, Jerrold E; West, Matthew

    2006-01-01

    This paper develops the theory of Abelian Routh reduction for discrete mechanical systems and applies it to the variational integration of mechanical systems with Abelian symmetry. The reduction of variational Runge-Kutta discretizations is considered, as well as the extent to which symmetry reduction and discretization commute. These reduced methods allow the direct simulation of dynamical features such as relative equilibria and relative periodic orbits that can be obscured or difficult to identify in the unreduced dynamics. The methods are demonstrated for the dynamics of an Earth orbiting satellite with a non-spherical J 2 correction, as well as the double spherical pendulum. The J 2 problem is interesting because in the unreduced picture, geometric phases inherent in the model and those due to numerical discretization can be hard to distinguish, but this issue does not appear in the reduced algorithm, where one can directly observe interesting dynamical structures in the reduced phase space (the cotangent bundle of shape space), in which the geometric phases have been removed. The main feature of the double spherical pendulum example is that it has a non-trivial magnetic term in its reduced symplectic form. Our method is still efficient as it can directly handle the essential non-canonical nature of the symplectic structure. In contrast, a traditional symplectic method for canonical systems could require repeated coordinate changes if one is evoking Darboux' theorem to transform the symplectic structure into canonical form, thereby incurring additional computational cost. Our method allows one to design reduced symplectic integrators in a natural way, despite the non-canonical nature of the symplectic structure

  3. Reduction of the N-component scalar model at the two-loop level

    International Nuclear Information System (INIS)

    Jakovac, A.

    1996-01-01

    Dimensional reduction of high temperature field theories improves IR features of their perturbative treatment. A crucial question is the following: What three-dimensional theory is representing the full system the most faithful way? A careful investigation of the induced three-dimensional counterterm structure of the finite temperature 4D O(N) symmetric scalar theory at the two-loop level leads to proposing the presence of nonlocal operators in the effective theory. A three-dimensional matching process is applied for the construction of the optimal local, superrenormalizable approximation. copyright 1996 The American Physical Society

  4. A two-dimensional lattice equation as an extension of the Heideman-Hogan recurrence

    Science.gov (United States)

    Kamiya, Ryo; Kanki, Masataka; Mase, Takafumi; Tokihiro, Tetsuji

    2018-03-01

    We consider a two dimensional extension of the so-called linearizable mappings. In particular, we start from the Heideman-Hogan recurrence, which is known as one of the linearizable Somos-like recurrences, and introduce one of its two dimensional extensions. The two dimensional lattice equation we present is linearizable in both directions, and has the Laurent and the coprimeness properties. Moreover, its reduction produces a generalized family of the Heideman-Hogan recurrence. Higher order examples of two dimensional linearizable lattice equations related to the Dana Scott recurrence are also discussed.

  5. Towards realistic models from Higher-Dimensional theories with Fuzzy extra dimensions

    CERN Document Server

    Gavriil, D.; Zoupanos, G.

    2014-01-01

    We briefly review the Coset Space Dimensional Reduction (CSDR) programme and the best model constructed so far and then we present some details of the corresponding programme in the case that the extra dimensions are considered to be fuzzy. In particular, we present a four-dimensional $\\mathcal{N} = 4$ Super Yang Mills Theory, orbifolded by $\\mathbb{Z}_3$, which mimics the behaviour of a dimensionally reduced $\\mathcal{N} = 1$, 10-dimensional gauge theory over a set of fuzzy spheres at intermediate high scales and leads to the trinification GUT $SU(3)^3$ at slightly lower, which in turn can be spontaneously broken to the MSSM in low scales.

  6. Ecosystem Approach To Flood Disaster Risk Reduction

    Directory of Open Access Journals (Sweden)

    RK Kamble

    2013-12-01

    Full Text Available India is one of the ten worst disaster prone countries of the world. The country is prone to disasters due to number of factors; both natural and anthropogenic, including adverse geo-climatic conditions, topographical features, environmental degradation, population growth, urbanisation, industrlisation, non-scientific development practices etc. The factors either in original or by accelerating the intensity and frequency of disasters are responsible for heavy toll of human lives and disrupting the life support systems in the country. India has 40 million hectares of the flood-prone area, on an average, flood affect an area of around 7.5 million hectares per year. Knowledge of environmental systems and processes are key factors in the management of disasters, particularly the hydro-metrological ones. Management of flood risk and disaster is a multi-dimensional affair that calls for interdisciplinary approach. Ecosystem based disaster risk reduction builds on ecosystem management principles, strategies and tools in order to maximise ecosystem services for risk reduction. This perspective takes into account the integration of social and ecological systems, placing people at the centre of decision making. The present paper has been attempted to demonstrate how ecosystem-based approach can help in flood disaster risk reduction. International Journal of Environment, Volume-2, Issue-1, Sep-Nov 2013, Pages 70-82 DOI: http://dx.doi.org/10.3126/ije.v2i1.9209

  7. Economical benzene emission reduction

    International Nuclear Information System (INIS)

    Schuetz, R.

    1999-01-01

    Benzene has been classified as a toxic compound under the Canadian Environmental Protection Act. This has prompted the Alberta Energy and Utilities Board (AEUB) to introduce specific reporting and monitoring guidelines for the oil and gas industry regarding excessive benzene emissions. Glycol dehydration units have been determined to be the major single source of benzene emissions causing air and soil pollution. DualTank Corp. has designed a condensation and storage tank unit to enhance emission reduction, odour elimination and liquid recovery from dehydration units. Their newly designed combined tank unit consists of a large, uninsulated surface area for cooling, and an excessive internal volume for increased retention time. The first prototype was installed in December 1998 at an Enerplus Resources Site. The system provides excellent benzene emission reduction and the elimination of odours and visual plumes. Effective January 1, 1999, the petroleum and natural gas industry must either clean up excessive emissions voluntarily or face government imposed regulations, facility shutdowns and/or fines. 1 fig

  8. LOFT data reduction

    International Nuclear Information System (INIS)

    Norman, N.L.

    1975-08-01

    The Loss-of-Fluid Test (LOFT) Facility is an experimental facility built around a ''scaled'' version of a large pressurized water reactor (LPWR). LOFT will be used to run loss-of-coolant experiments (LOCEs) and to acquire the necessary data required ''to evaluate the adequacy and improve the analytical methods currently used to predict the loss-of-coolant accident (LOCA) response of LPWRs'' and ''to identify and investigate any unexpected event(s) or threshold(s) in the response of either the plant or the engineered safety features and develop analytical techniques that adequately describe and account for the unexpected behavior(s)''. During the LOCE this required data will be acquired and recorded in both analog and digital modes. Subsequent to the test the analog data will also be converted to the raw digital mode. This raw digital data will be converted to the desired engineering units using the LOFT Data Reduction System. This system is implemented on the IBM 360/75 and is a part of a commercially available data processing program called MAC/RAN III. The theory of reducing LOFT data to engineering units and the application of the MAC/ RAN III system to accomplish this reduction is given. (auth)

  9. Islam and harm reduction.

    Science.gov (United States)

    Kamarulzaman, A; Saifuddeen, S M

    2010-03-01

    Although drugs are haram and therefore prohibited in Islam, illicit drug use is widespread in many Islamic countries throughout the world. In the last several years increased prevalence of this problem has been observed in many of these countries which has in turn led to increasing injecting drug use driven HIV/AIDS epidemic across the Islamic world. Whilst some countries have recently responded to the threat through the implementation of harm reduction programmes, many others have been slow to respond. In Islam, The Quran and the Prophetic traditions or the Sunnah are the central sources of references for the laws and principles that guide the Muslims' way of life and by which policies and guidelines for responses including that of contemporary social and health problems can be derived. The preservation and protection of the dignity of man, and steering mankind away from harm and destruction are central to the teachings of Islam. When viewed through the Islamic principles of the preservation and protection of the faith, life, intellect, progeny and wealth, harm reduction programmes are permissible and in fact provide a practical solution to a problem that could result in far greater damage to the society at large if left unaddressed. Copyright (c) 2009. Published by Elsevier B.V.

  10. Emergency planning zone reduction

    International Nuclear Information System (INIS)

    Edwards, C.

    2002-01-01

    This paper describes the process used by a large industrial Department of Energy (DOE) site to communicate changing hazards to its stakeholders and install the confidence necessary to implement the resulting emergency planning changes. Over the last decade as the sites missions have shifted from full-scale production to a greater emphasis on environmental restoration and waste management, the off-site threat from its operations has substantially decreased. The challenge was to clearly communicate the reduced hazards, install confidence in the technical analysis that documented the hazard reduction, and obtain stakeholder buy-in on the path forward to change the emergency management program. The most significant change to the emergency management program was the proposed reduction of the sites Emergency Planning Zone (EPZ). As the EPZ is defined as an area for which planning is needed to protect the public in the event of an accident, the process became politically challenging. An overview of how the site initially approached this problem and then learned to more substantially involve the state and local emergency preparedness agencies and the local Citizens Advisory Board will be presented. (author)

  11. Reduction operators of Burgers equation.

    Science.gov (United States)

    Pocheketa, Oleksandr A; Popovych, Roman O

    2013-02-01

    The solution of the problem on reduction operators and nonclassical reductions of the Burgers equation is systematically treated and completed. A new proof of the theorem on the special "no-go" case of regular reduction operators is presented, and the representation of the coefficients of operators in terms of solutions of the initial equation is constructed for this case. All possible nonclassical reductions of the Burgers equation to single ordinary differential equations are exhaustively described. Any Lie reduction of the Burgers equation proves to be equivalent via the Hopf-Cole transformation to a parameterized family of Lie reductions of the linear heat equation.

  12. Consistência interna e fatorial do Inventário Multifatorial de Coping para Adolescentes Reliability and confirmatory factorial analysis of the Multifactor Coping for Adolescents Inventory with Brazilian students

    Directory of Open Access Journals (Sweden)

    Marcos Alencar Abaide Balbinotti

    2006-12-01

    Full Text Available Coping é um construto multidimensional relativo às formas como as pessoas lidam com situações estressantes. Diversas pesquisas assinalam a importância dessas "respostas de enfrentamento". Este estudo visa verificar os índices de consistência interna e fatorial confirmatórios do Inventário Multifatorial de Coping para Adolescentes (IMCA-43. Assim, a coleta de dados foi realizada mediante aplicações coletivas, em sala de aula, em uma amostra de 285 estudantes do ensino fundamental e médio, de ambos os sexos e com idades variando de 13 a 18 anos. Os resultados dos índices alfa de Cronbach (0,71 a 0,89 foram satisfatórios. A adequação aos modelos tridimensional (x2/gl = 2,85; GFI = 0,757; AGFI = 0,724; RMSEA = 0,081 tetradimensional (x2/gl = 2,44; GFI = 0,724; AGFI = 0,695; RMSEA = 0,071 e pentadimensional (x2/gl = 2,32; GFI = 0,750; AGFI = 0,723; RMSEA = 0,068 é pouco recomendada. Os resultados indicam serem necessárias pesquisas continuadas a fim de melhorar certas qualidades métricas deste instrumento.Coping is a multidimensional concept concerning how people face and deal with stressful situations. Researches have been showing the importance of these forms of behavior responses. This study aimed to measure the internal consistency of the Multifactorial Inventory of Coping for Adolescents (IMCA-43 and evaluate the fit of the model through confirmatory factorial analysis. A sample of 285 students of Intermediate and High School, of both sexes, with ages ranging from 13 to 18 years old was used. The data was colected colectivelly in their classrooms. The results of the Cronbach alfa (0,71 to 0,89 were satisfactory. The index of adequacy for the tri-dimensional model (x2/gl = 2,85; GFI = 0,757; AGFI = 0,724; RMSEA = 0,081, tetra-dimensional (x2/gl = 2,44; GFI = 0,724; AGFI = 0,695; RMSEA = 0,071 and penta-dimensional (x2/gl = 2,32; GFI = 0,750; AGFI = 0,723; RMSEA = 0,068 are non-recommended for the fit of the model. The results

  13. Oxygen Reduction on Platinum

    DEFF Research Database (Denmark)

    Nesselberger, Markus

    . The influence of the ion adsorption strength, which is observed in the “particle size studies” on the oxygen reduction rate on Pt/C catalysts, is further investigated under similar reaction conditions by infrared spectroscopy. The designed in situ electrochemical ATR-FTIR setup features a high level...... of instrument automation and online data treatment, and provides welldefined mass transport conditions enabling kinetic measurements. A modified electrochemical / spectroscopic interface is presented allowing the exclusive investigation of the Pt/C catalyst layer. Three types of potential dependent adsorption...... adsorption on Pt does not block the ORR directly. Instead, the onset of oxide formation with the concomitant conversion of the anion adsorbate layer is the decisive blocking mechanism....

  14. Multiple gas reduction strategy

    Energy Technology Data Exchange (ETDEWEB)

    A. Kurosawa [Institute of Applied Energy, Tokyo (Japan)

    2003-07-01

    Future global warming has a close relationship with the abatement potential of six greenhouse gases (GHGs), including carbon dioxide (CO{sub 2}), methane (CH{sub 4}), nitrous oxide (N{sub 2}O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). Therefore, multiple gas reduction flexibility should be assessed. The emission of each non-CO{sub 2} GHG is calculated endogenously by the sum of the product of the emission factor and the endogenous activity index using an integrated assessment model, GRAPE (Global Relationship Assessment to Protect the Environment). The model consists of five modules dealing with issues on energy, climate, land use, macroeconomics and environmental impacts. The uncertainty in the non-CO{sub 2} GHG emission inventory and emission factors is discussed. 5 refs., 3 figs., 1 tab.

  15. Minimal Reducts with Grasp

    Directory of Open Access Journals (Sweden)

    Iris Iddaly Mendez Gurrola

    2011-03-01

    Full Text Available The proper detection of patient level of dementia is important to offer the suitable treatment. The diagnosis is based on certain criteria, reflected in the clinical examinations. From these examinations emerge the limitations and the degree in which each patient is in. In order to reduce the total of limitations to be evaluated, we used the rough set theory, this theory has been applied in areas of the artificial intelligence such as decision analysis, expert systems, knowledge discovery, classification with multiple attributes. In our case this theory is applied to find the minimal limitations set or reduct that generate the same classification that considering all the limitations, to fulfill this purpose we development an algorithm GRASP (Greedy Randomized Adaptive Search Procedure.

  16. Aircraft engine pollution reduction.

    Science.gov (United States)

    Rudey, R. A.

    1972-01-01

    The effect of engine operation on the types and levels of the major aircraft engine pollutants is described and the major factors governing the formation of these pollutants during the burning of hydrocarbon fuel are discussed. Methods which are being explored to reduce these pollutants are discussed and their application to several experimental research programs are pointed out. Results showing significant reductions in the levels of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen obtained from experimental combustion research programs are presented and discussed to point out potential application to aircraft engines. An experimental program designed to develop and demonstrate these and other advanced, low pollution combustor design methods is described. Results that have been obtained to date indicate considerable promise for reducing advanced engine exhaust pollutants to levels significantly below current engines.

  17. Mindfulness-Based Stress Reduction

    Science.gov (United States)

    ... R S T U V W X Y Z Mindfulness-Based Stress Reduction (MBSR) Information 6 Things You ... Disease and Dementia (12/20/13) Research Spotlights Mindfulness-Based Stress Reduction, Cognitive-Behavioral Therapy Shown To ...

  18. Consumer's Guide to Radon Reduction

    Science.gov (United States)

    ... Labs and Research Centers Radon Contact Us Share Consumer's Guide to Radon Reduction: How to Fix Your ... See EPA’s About PDF page to learn more. Consumer's Guide to Radon Reduction: How to Fix Your ...

  19. Confluence reduction for Markov automata

    NARCIS (Netherlands)

    Timmer, Mark; Katoen, Joost P.; van de Pol, Jaco; Stoelinga, Mariëlle Ida Antoinette

    2016-01-01

    Markov automata are a novel formalism for specifying systems exhibiting nondeterminism, probabilistic choices and Markovian rates. As expected, the state space explosion threatens the analysability of these models. We therefore introduce confluence reduction for Markov automata, a powerful reduction

  20. Hazardous material reduction initiative

    International Nuclear Information System (INIS)

    Nichols, D.H.

    1995-02-01

    The Hazardous Material Reduction Initiative (HMRI) explores using the review of purchase requisitions to reduce both the use of hazardous materials and the generation of regulated and nonregulated wastes. Based on an 11-month program implemented at the Hanford Site, hazardous material use and waste generation was effectively reduced by using a centralized procurement control program known as HMRI. As expected, several changes to the original proposal were needed during the development/testing phase of the program to accommodate changing and actual conditions found at the Hanford Site. The current method requires a central receiving point within the Procurement Organization to review all purchase requisitions for potentially Occupational Safety and Health Administration (OSHA) hazardous products. Those requisitions (approximately 4% to 6% of the total) are then forwarded to Pollution Prevention personnel for evaluation under HMRI. The first step is to determine if the requested item can be filled by existing or surplus material. The requisitions that cannot filled by existing or surplus material are then sorted into two groups based on applicability to the HMRI project. For example, laboratory requests for analytical reagents or standards are excluded and the purchase requisitions are returned to Procurement for normal processing because, although regulated, there is little opportunity for source reduction due to the strict protocols followed. Each item is then checked to determine if it is regulated or not. Regulated items are prioritized based on hazardous contents, quantity requested, and end use. Copies of these requisitions are made and the originals are returned to Procurement within 1-hr. Since changes to the requisition can be made at later stages during procurement, the HMRI fulfills one of its original premises in that it does not slow the procurement process

  1. Dose Reduction Techniques

    International Nuclear Information System (INIS)

    WAGGONER, L.O.

    2000-01-01

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program

  2. Dose Reduction Techniques

    Energy Technology Data Exchange (ETDEWEB)

    WAGGONER, L.O.

    2000-05-16

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program.

  3. Dimensional analysis in field theory

    International Nuclear Information System (INIS)

    Stevenson, P.M.

    1981-01-01

    Dimensional Transmutation (the breakdown of scale invariance in field theories) is reconciled with the commonsense notions of Dimensional Analysis. This makes possible a discussion of the meaning of the Renormalisation Group equations, completely divorced from the technicalities of renormalisation. As illustrations, I describe some very farmiliar QCD results in these terms

  4. On four dimensional mirror symmetry

    International Nuclear Information System (INIS)

    Losev, A.; Nekrasov, N.; Shatashvili, S.

    2000-01-01

    A conjecture relating instanton calculus in four dimensional supersymmetric theories and the deformation theory of Lagrangian submanifolds in C 2r invariant under a (subgroup of) Sp(2r,Z) is formulated. This is a four dimensional counterpart of the mirror symmetry of topological strings (relating Gromov-Witten invariants and generalized variations of Hodge structure). (orig.)

  5. Low-dimensional molecular metals

    CERN Document Server

    Toyota, Naoki; Muller, Jens

    2007-01-01

    Assimilating research in the field of low-dimensional metals, this monograph provides an overview of the status of research on quasi-one- and two-dimensional molecular metals, describing normal-state properties, magnetic field effects, superconductivity, and the phenomena of interacting p and d electrons.

  6. Two-dimensional metamaterial optics

    International Nuclear Information System (INIS)

    Smolyaninov, I I

    2010-01-01

    While three-dimensional photonic metamaterials are difficult to fabricate, many new concepts and ideas in the metamaterial optics can be realized in two spatial dimensions using planar optics of surface plasmon polaritons. In this paper we review recent progress in this direction. Two-dimensional photonic crystals, hyperbolic metamaterials, and plasmonic focusing devices are demonstrated and used in novel microscopy and waveguiding schemes

  7. On reductions of the discrete Kadomtsev-Petviashvili-type equations

    Science.gov (United States)

    Fu, Wei; Nijhoff, Frank W.

    2017-12-01

    The reduction by restricting the spectral parameters k and k\\prime on a generic algebraic curve of degree N is performed for the discrete AKP, BKP and CKP equations, respectively. A variety of two-dimensional discrete integrable systems possessing a more general solution structure arise from the reduction, and in each case a unified formula for the generic positive integer N≥slant 2 is given to express the corresponding reduced integrable lattice equations. The obtained extended two-dimensional lattice models give rise to many important integrable partial difference equations as special degenerations. Some new integrable lattice models such as the discrete Sawada-Kotera, Kaup-Kupershmidt and Hirota-Satsuma equations in extended form are given as examples within the framework.

  8. Alcohol harm reduction in Europe

    DEFF Research Database (Denmark)

    Herring, Rachel; Betsy, Thom; Beccaria, Franca

    2010-01-01

    The EMCDDA’s 10th scientific monograph, entitled Harm reduction: evidence, impacts and challenges provides a comprehensive overview of the harm reduction field. Part I of the monograph looks back at the emergence of harm reduction approaches and their diffusion, and explores the concept from diff...

  9. Higher dimensional loop quantum cosmology

    International Nuclear Information System (INIS)

    Zhang, Xiangdong

    2016-01-01

    Loop quantum cosmology (LQC) is the symmetric sector of loop quantum gravity. In this paper, we generalize the structure of loop quantum cosmology to the theories with arbitrary spacetime dimensions. The isotropic and homogeneous cosmological model in n + 1 dimensions is quantized by the loop quantization method. Interestingly, we find that the underlying quantum theories are divided into two qualitatively different sectors according to spacetime dimensions. The effective Hamiltonian and modified dynamical equations of n + 1 dimensional LQC are obtained. Moreover, our results indicate that the classical big bang singularity is resolved in arbitrary spacetime dimensions by a quantum bounce. We also briefly discuss the similarities and differences between the n + 1 dimensional model and the 3 + 1 dimensional one. Our model serves as a first example of higher dimensional loop quantum cosmology and offers the possibility to investigate quantum gravity effects in higher dimensional cosmology. (orig.)

  10. Model Reduction of Fuzzy Logic Systems

    Directory of Open Access Journals (Sweden)

    Zhandong Yu

    2014-01-01

    Full Text Available This paper deals with the problem of ℒ2-ℒ∞ model reduction for continuous-time nonlinear uncertain systems. The approach of the construction of a reduced-order model is presented for high-order nonlinear uncertain systems described by the T-S fuzzy systems, which not only approximates the original high-order system well with an ℒ2-ℒ∞ error performance level γ but also translates it into a linear lower-dimensional system. Then, the model approximation is converted into a convex optimization problem by using a linearization procedure. Finally, a numerical example is presented to show the effectiveness of the proposed method.

  11. Reduction of seismic response in breeder plants

    International Nuclear Information System (INIS)

    Tajirian, F.F.; Somes, N.F.; Todeschini, R.A.

    1984-01-01

    Thin-walled vessels to be used in the Nuclear Steam Supply Systems (NSSS) of future LMFBR's will be more sensitive to seismic excitation than their equivalents used in conventional LWR plants. Optimization studies of building arrangement have indicated that embedment of future plants may be one feasible strategy for reducing seismic response. This paper presents the results of a three-dimensional soil-structure interaction analysis using the computer program SASSI. Two types of embedded buildings are considered: full embedment of the nuclear island, and embedment of the reactor cavity alone. A comparison, between the response of the embedded structure with that of a plant supported on the surface, indicates that the seismic response at the reactor vessel support ledge can be lowered by embedment of either the entire nuclear island or the reactor cavity alone. This reduction is larger when the plant is embedded in a softer site due to the increased effect of soil-structure interaction

  12. Model Reduction in Biomechanics

    Science.gov (United States)

    Feng, Yan

    mechanical parameters from experimental results. However, in real biological world, these homogeneous and isotropic assumptions are usually invalidate. Thus, instead of using hypothesized model, a specific continuum model at mesoscopic scale can be introduced based upon data reduction of the results from molecular simulations at atomistic level. Once a continuum model is established, it can provide details on the distribution of stresses and strains induced within the biomolecular system which is useful in determining the distribution and transmission of these forces to the cytoskeletal and sub-cellular components, and help us gain a better understanding in cell mechanics. A data-driven model reduction approach to the problem of microtubule mechanics as an application is present, a beam element is constructed for microtubules based upon data reduction of the results from molecular simulation of the carbon backbone chain of alphabeta-tubulin dimers. The data base of mechanical responses to various types of loads from molecular simulation is reduced to dominant modes. The dominant modes are subsequently used to construct the stiffness matrix of a beam element that captures the anisotropic behavior and deformation mode coupling that arises from a microtubule's spiral structure. In contrast to standard Euler-Bernoulli or Timoshenko beam elements, the link between forces and node displacements results not from hypothesized deformation behavior, but directly from the data obtained by molecular scale simulation. Differences between the resulting microtubule data-driven beam model (MTDDBM) and standard beam elements are presented, with a focus on coupling of bending, stretch, shear deformations. The MTDDBM is just as economical to use as a standard beam element, and allows accurate reconstruction of the mechanical behavior of structures within a cell as exemplified in a simple model of a component element of the mitotic spindle.

  13. Quantum fluctuations and spontaneous compactification of eleven-dimensional gravity

    International Nuclear Information System (INIS)

    Nguen Van Hieu.

    1985-01-01

    The reduction of the eleven-dimensional pure gravity to the field theory in the four-dimensional Minkowski space-time by means of the spontaneous compactification of the extra dimensions is investigated. The contribution of the quantum fluctuations of the eleven-dimen-- sonal second rank symmetric tensor field to the curvatures of the space-time and the compactified space of the extra dimensions are calculated in the one-loop approximation. It is shown that there exist the values of the cosmological constant for which tachions are absent. As a result, self-consistent quantum field theory is obtained in spontaneous compactified Minkowski space M 4 xS 7 ,is where M 4 is Minkowski space-time, and S 7 is seven-dimensional sphere

  14. Universal contributions to scalar masses from five dimensional supergravity

    CERN Document Server

    Dudas, Emilian

    2012-01-01

    We compute the effective Kahler potential for matter fields in warped compactifications, starting from five dimensional gauged supergravity, as a function of the matter fields localization. We show that truncation to zero modes is inconsistent and the tree-level exchange of the massive gravitational multiplet is needed for consistency of the four-dimensional theory. In addition to the standard Kahler coming from dimensional reduction, we find the quartic correction coming from integrating out the gravity multiplet. We apply our result to the computation of scalar masses, by assuming that the SUSY breaking field is a bulk hypermultiplet. In the limit of extreme opposite localization of the matter and the spurion fields, we find zero scalar masses, consistent with sequestering arguments. Surprisingly enough, for all the other cases the scalar masses are tachyonic. This suggests the holographic interpretation that a CFT sector always generates operators contributing in a tachyonic way to scalar masses. Viability...

  15. Reduction of blue tungsten oxide

    International Nuclear Information System (INIS)

    Wilken, T.; Wert, C.; Woodhouse, J.; Morcom, W.

    1975-01-01

    A significant portion of commercial tungsten is produced by hydrogen reduction of oxides. Although several modes of reduction are possible, hydrogen reduction is used where high purity tungsten is required and where the addition of other elements or compounds is desired for modification of the metal, as is done for filaments in the lamp industry. Although several investigations of the reduction of oxides have been reported (1 to 5), few principles have been developed which can aid in assessment of current commercial practice. The reduction process was examined under conditions approximating commercial practice. The specific objectives were to determine the effects of dopants, of water vapor in the reducing atmosphere, and of reduction temperature upon: (1) the rate of the reaction by which blue tungsten oxide is reduced to tungsten metal, (2) the intermediate oxides associated with reduction, and (3) the morphology of the resulting tungsten powder

  16. Three-dimensional quantum electrodynamics as an effective interaction

    International Nuclear Information System (INIS)

    Abdalla, E.; Carvalho Filho, F.M. de

    1995-10-01

    We obtain a Quantum Electrodynamics in 2 + 1 dimensions by applying a Kaluza-Klein type method of dimensional reduction to Quantum Electrodynamics in 3 + 1 dimensions rendering the model more realistic to application in solid-state systems, invariant under translations in one direction. We show that the model obtained leads to an effective action exhibiting an interesting phase structure and that the generated Chern-Simons term survives only in the broken phase. (author). 20 refs

  17. Size reduction machine

    International Nuclear Information System (INIS)

    Fricke, V.

    1999-01-01

    The Size Reduction Machine (SRM) is a mobile platform capable of shearing various shapes and types of metal components at a variety of elevations. This shearing activity can be performed without direct physical movement and placement of the shear head by the operator. The base unit is manually moved and roughly aligned to each cut location. The base contains the electronics: hydraulic pumps, servos, and actuators needed to move the shear-positioning arm. The movable arm allows the shear head to have six axes of movement and to cut to within 4 inches of a wall surface. The unit has a slick electrostatic capture coating to assist in external decontamination. Internal contamination of the unit is controlled by a high-efficiency particulate air (HEPA) filter on the cooling inlet fan. The unit is compact enough to access areas through a 36-inch standard door opening. This paper is an Innovative Technology Summary Report designed to provide potential users with the information they need to quickly determine if a technology would apply to a particular environmental management problem. They also are designed for readers who may recommend that a technology be considered by prospective users

  18. Electrochemical reduction of NOx

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund

    NO and NO2 (collectively referred to as NOx) are air pollutants, and the largest single contributor to NOx pollution is automotive exhaust. This study investigates electrochemical deNOx, a technology which aims to remove NOx from automotive diesel exhaust by electrochemical reduction of NOx to N2...... and O2. The focus in this study is on improving the activity and selectivity of solid oxide electrodes for electrochemical deNOx by addition of NOx storage compounds to the electrodes. Two different composite electrodes, La0.85Sr0.15MnO3-δ-Ce0.9Gd0.1O1.95 (LSM15-CGO10) and La0.85Sr0.15FeO3-δ-Ce0.9Gd0.1O......1.95 (LSF15-CGO10), have been investigated in combination with three different NOx storage compounds: BaO, K2O and MnOx. The main focus in the investigation has been on conversion measurements and electrochemical characterization, the latter by means of electrochemical impedance spectroscopy...

  19. Syncrude emissions reduction project

    Energy Technology Data Exchange (ETDEWEB)

    Fiedler, M.A. [Alstom Power Inc., Knoxville, TN (United States); Ibbotson, P. [Syncrude Canada Ltd., Calgary, AB (Canada)

    2008-07-01

    This paper described an emissions reduction project conducted by Syncrude Canada and various other companies currently developing and processing oil sands in Alberta. Syncrude's upgrader expansion program included the installation of an ammonia-based wet flue gas desulfurizer (FGD) designed to remove sulphur dioxide (SO{sub 2}) from a coker train. Syncrude is also installing the FGD technology at its existing plants. It is expected that installation of the FGDs will reduced total site emissions of SO{sub 2} by 60 per cent. The fluid cokers are used to crack the long hydrocarbon chain bitumen molecules into shorter molecules. It is expected that the FGD system will also reduce particulate and SO{sub 3} levels. The FGD system was selected after an evaluation of technologies used by the coal-fired power industry. A dry FGD system was selected to operate above the water saturation temperature of the flue gas. Calcium oxide was used as a reagent. Hot gas was quenched in a spray dryer absorber with a slurry of calcium hydroxide. Rotary atomizers were used to developer uniform droplets of slurry. The system's fabric filter was a low ratio reverse gas-cleaned unit. Particulate matter from the gases was deposited on the interior of the filter bags. Clean hot gas was drawn through reverse gas fans into a reverse gas manifold. A timeline of the FGD technology installation process was included. 3 tabs., 28 figs.

  20. Spinors and supersymmetry in four-dimensional Euclidean space

    International Nuclear Information System (INIS)

    McKeon, D.G.C.; Sherry, T.N.

    2001-01-01

    Spinors in four-dimensional Euclidean space are treated using the decomposition of the Euclidean space SO(4) symmetry group into SU(2)xSU(2). Both 2- and 4-spinor representations of this SO(4) symmetry group are shown to differ significantly from the corresponding spinor representations of the SO(3, 1) symmetry group in Minkowski space. The simplest self conjugate supersymmetry algebra allowed in four-dimensional Euclidean space is demonstrated to be an N=2 supersymmetry algebra which resembles the N=2 supersymmetry algebra in four-dimensional Minkowski space. The differences between the two supersymmetry algebras gives rise to different representations; in particular an analysis of the Clifford algebra structure shows that the momentum invariant is bounded above by the central charges in 4dE, while in 4dM the central charges bound the momentum invariant from below. Dimensional reduction of the N=1 SUSY algebra in six-dimensional Minkowski space (6dM) to 4dE reproduces our SUSY algebra in 4dE. This dimensional reduction can be used to introduce additional generators into the SUSY algebra in 4dE. Well known interpolating maps are used to relate the N=2 SUSY algebra in 4dE derived in this paper to the N=2 SUSY algebra in 4dM. The nature of the spinors in 4dE allows us to write an axially gauge invariant model which is shown to be both Hermitian and anomaly-free. No equivalent model exists in 4dM. Useful formulae in 4dE are collected together in two appendixes

  1. Three dimensional energy profile:

    International Nuclear Information System (INIS)

    Kowsari, Reza; Zerriffi, Hisham

    2011-01-01

    The provision of adequate, reliable, and affordable energy has been considered as a cornerstone of development. More than one-third of the world's population has a very limited access to modern energy services and suffers from its various negative consequences. Researchers have been exploring various dimensions of household energy use in order to design strategies to provide secure access to modern energy services. However, despite more than three decades of effort, our understanding of household energy use patterns is very limited, particularly in the context of rural regions of the developing world. Through this paper, the past and the current trends in the field of energy analysis are investigated. The literature on rural energy and energy transition in developing world has been explored and the factors affecting households' decisions on energy use are listed. The and the factors affecting households' decisions on energy use are listed. The gaps identified in the literature on rural household energy analysis provide a basis for developing an alternative model that can create a more realistic view of household energy use. The three dimensional energy profile is presented as a new conceptual model for assessment of household energy use. This framework acts as a basis for building new theoretical and empirical models of rural household energy use. - Highlights: ► Reviews literature on household energy, energy transitions and decision-making in developing countries. ► Identifies gaps in rural household energy analysis and develops a new conceptual framework. ► The 3-d energy profile provides a holistic view of household energy system characteristics. ► Illustrates the use of the framework for understanding household energy transitions.

  2. Three-dimensional echocardiography

    International Nuclear Information System (INIS)

    Buck, Thomas

    2011-01-01

    Presents tips and tricks for beginners and experts Provides educational material for 3D training courses Features comprehensively illustrated cases Includes an accompanying DVD with video clips of all sample cases Three-dimensional echocardiography is the most recent fundamental advancement in echocardiography. Since real-time 3D echocardiography became commercially available in 2002, it has rapidly been accepted in echo labs worldwide. This book covers all clinically relevant aspects of this fascinating new technology, including a comprehensive explanation of its basic principles, practical aspects of clinical application, and detailed descriptions of specific uses in the broad spectrum of clinically important heart disease. The book was written by a group of well-recognized international experts in the field, who have not only been involved in the scientific and clinical evolution of 3D echocardiography since its inception but are also intensively involved in expert training courses. As a result, the clear focus of this book is on the practical application of 3D echocardiography in daily clinical routine with tips and tricks for both beginners and experts, accompanied by more than 150 case examples comprehensively illustrated in more than 800 images and more than 500 videos provided on a DVD. In addition to an in-depth review of the most recent literature on real-time 3D echocardiography, this book represents an invaluable reference work for beginners and expert users of 3D echocardiography. - Tips and tricks for beginners and experts - Educational material for 3D training courses - Comprehensively illustrated cases - DVD with video clips of all sample cases.

  3. Deliberating emission reduction options

    Energy Technology Data Exchange (ETDEWEB)

    Dowd, A. M.; Rodriguez, M.; Jeanneret, T. [Commonwealth Scientific and Industrial Research Organisation CSIRO, 37 Graham Rd, Highett VIC 3190 (Australia); De Best-Waldhober, M.; Straver, K.; Mastop, J.; Paukovic, M. [Energy research Centre of the Netherlands ECN, Policy Studies, Amsterdam (Netherlands)

    2012-06-15

    For more than 20 years there has been a concerted international effort toward addressing climate change. International conventions, such as the United Nations Foreign Convention on Climate Change (UNFCCC; ratified in 1994), have been established by committed nations seeking to address global climate change through the reduction of greenhouse gases emitted into the Earth's atmosphere (Global CCS Institute, 2011). Long recognised as the most crucial of the greenhouse gases to impact global warming, the majority of carbon dioxide's anthropogenic global emissions are directly related to fuel combustion of which both Australia and the Netherlands' energy production is significantly reliant. Both these nations will need to consider many opinions and make hard decisions if alternative energy options are to be implemented at the scale that is required to meet international emission targets. The decisions that are required not only need to consider the many options available but also their consequences. Along with politicians, policy developers and industry, the general public also need to be active participants in deciding which energy options, and their subsequent consequences, are acceptable for implementation at the national level. Access to balanced and factual information is essential in establishing informed opinions on the many policy options available. Past research has used several methods to measure public perceptions and opinions yet for complex issues, such as emission reduction, some of these methods have shown to be problematic. For example, semi structured interviews can provide data that is flexible and context rich yet is does also come with the limitations such as it seldom provides a practical assessment that can be utilised from researcher to researcher, across disciplines and public participation techniques. Surveys on the other hand usually address these limitations but surveys that do not encourage comparison of information or ask participants to

  4. Deliberating emission reduction options

    Energy Technology Data Exchange (ETDEWEB)

    Dowd, A.M.; Rodriguez, M.; Jeanneret, T. [Commonwealth Scientific and Industrial Research Organisation CSIRO, 37 Graham Rd, Highett VIC 3190 (Australia); De Best-Waldhober, M.; Straver, K.; Mastop, J.; Paukovic, M. [Energy research Centre of the Netherlands ECN, Policy Studies, Amsterdam (Netherlands)

    2012-06-15

    For more than 20 years there has been a concerted international effort toward addressing climate change. International conventions, such as the United Nations Foreign Convention on Climate Change (UNFCCC; ratified in 1994), have been established by committed nations seeking to address global climate change through the reduction of greenhouse gases emitted into the Earth's atmosphere (Global CCS Institute, 2011). Long recognised as the most crucial of the greenhouse gases to impact global warming, the majority of carbon dioxide's anthropogenic global emissions are directly related to fuel combustion of which both Australia and the Netherlands' energy production is significantly reliant. Both these nations will need to consider many opinions and make hard decisions if alternative energy options are to be implemented at the scale that is required to meet international emission targets. The decisions that are required not only need to consider the many options available but also their consequences. Along with politicians, policy developers and industry, the general public also need to be active participants in deciding which energy options, and their subsequent consequences, are acceptable for implementation at the national level. Access to balanced and factual information is essential in establishing informed opinions on the many policy options available. Past research has used several methods to measure public perceptions and opinions yet for complex issues, such as emission reduction, some of these methods have shown to be problematic. For example, semi structured interviews can provide data that is flexible and context rich yet is does also come with the limitations such as it seldom provides a practical assessment that can be utilised from researcher to researcher, across disciplines and public participation techniques. Surveys on the other hand usually address these limitations but surveys that do not encourage comparison of information or ask

  5. Principal Components as a Data Reduction and Noise Reduction Technique

    Science.gov (United States)

    Imhoff, M. L.; Campbell, W. J.

    1982-01-01

    The potential of principal components as a pipeline data reduction technique for thematic mapper data was assessed and principal components analysis and its transformation as a noise reduction technique was examined. Two primary factors were considered: (1) how might data reduction and noise reduction using the principal components transformation affect the extraction of accurate spectral classifications; and (2) what are the real savings in terms of computer processing and storage costs of using reduced data over the full 7-band TM complement. An area in central Pennsylvania was chosen for a study area. The image data for the project were collected using the Earth Resources Laboratory's thematic mapper simulator (TMS) instrument.

  6. Three New (2+1)-dimensional Integrable Systems and Some Related Darboux Transformations

    International Nuclear Information System (INIS)

    Guo Xiu-Rong

    2016-01-01

    We introduce two operator commutators by using different-degree loop algebras of the Lie algebra A 1 , then under the framework of zero curvature equations we generate two (2+1)-dimensional integrable hierarchies, including the (2+1)-dimensional shallow water wave (SWW) hierarchy and the (2+1)-dimensional Kaup-Newell (KN) hierarchy. Through reduction of the (2+1)-dimensional hierarchies, we get a (2+1)-dimensional SWW equation and a (2+1)-dimensional KN equation. Furthermore, we obtain two Darboux transformations of the (2+1)-dimensional SWW equation. Similarly, the Darboux transformations of the (2+1)-dimensional KN equation could be deduced. Finally, with the help of the spatial spectral matrix of SWW hierarchy, we generate a (2+1) heat equation and a (2+1) nonlinear generalized SWW system containing inverse operators with respect to the variables x and y by using a reduction spectral problem from the self-dual Yang-Mills equations. (paper)

  7. Three New (2+1)-dimensional Integrable Systems and Some Related Darboux Transformations

    Science.gov (United States)

    Guo, Xiu-Rong

    2016-06-01

    We introduce two operator commutators by using different-degree loop algebras of the Lie algebra A1, then under the framework of zero curvature equations we generate two (2+1)-dimensional integrable hierarchies, including the (2+1)-dimensional shallow water wave (SWW) hierarchy and the (2+1)-dimensional Kaup-Newell (KN) hierarchy. Through reduction of the (2+1)-dimensional hierarchies, we get a (2+1)-dimensional SWW equation and a (2+1)-dimensional KN equation. Furthermore, we obtain two Darboux transformations of the (2+1)-dimensional SWW equation. Similarly, the Darboux transformations of the (2+1)-dimensional KN equation could be deduced. Finally, with the help of the spatial spectral matrix of SWW hierarchy, we generate a (2+1) heat equation and a (2+1) nonlinear generalized SWW system containing inverse operators with respect to the variables x and y by using a reduction spectral problem from the self-dual Yang-Mills equations. Supported by the National Natural Science Foundation of China under Grant No. 11371361, the Shandong Provincial Natural Science Foundation of China under Grant Nos. ZR2012AQ011, ZR2013AL016, ZR2015EM042, National Social Science Foundation of China under Grant No. 13BJY026, the Development of Science and Technology Project under Grant No. 2015NS1048 and A Project of Shandong Province Higher Educational Science and Technology Program under Grant No. J14LI58

  8. Bioinspired surfaces for turbulent drag reduction.

    Science.gov (United States)

    Golovin, Kevin B; Gose, James W; Perlin, Marc; Ceccio, Steven L; Tuteja, Anish

    2016-08-06

    In this review, we discuss how superhydrophobic surfaces (SHSs) can provide friction drag reduction in turbulent flow. Whereas biomimetic SHSs are known to reduce drag in laminar flow, turbulence adds many new challenges. We first provide an overview on designing SHSs, and how these surfaces can cause slip in the laminar regime. We then discuss recent studies evaluating drag on SHSs in turbulent flow, both computationally and experimentally. The effects of streamwise and spanwise slip for canonical, structured surfaces are well characterized by direct numerical simulations, and several experimental studies have validated these results. However, the complex and hierarchical textures of scalable SHSs that can be applied over large areas generate additional complications. Many studies on such surfaces have measured no drag reduction, or even a drag increase in turbulent flow. We discuss how surface wettability, roughness effects and some newly found scaling laws can help explain these varied results. Overall, we discuss how, to effectively reduce drag in turbulent flow, an SHS should have: preferentially streamwise-aligned features to enhance favourable slip, a capillary resistance of the order of megapascals, and a roughness no larger than 0.5, when non-dimensionalized by the viscous length scale.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. © 2016 The Author(s).

  9. dimensional Jaulent–Miodek equations

    Indian Academy of Sciences (India)

    (2+1)-dimensional Jaulent–Miodek equation; the first integral method; kinks; ... and effective method for solving nonlinear partial differential equations which can ... of the method employed and exact kink and soliton solutions are constructed ...

  10. Weakly infinite-dimensional spaces

    International Nuclear Information System (INIS)

    Fedorchuk, Vitalii V

    2007-01-01

    In this survey article two new classes of spaces are considered: m-C-spaces and w-m-C-spaces, m=2,3,...,∞. They are intermediate between the class of weakly infinite-dimensional spaces in the Alexandroff sense and the class of C-spaces. The classes of 2-C-spaces and w-2-C-spaces coincide with the class of weakly infinite-dimensional spaces, while the compact ∞-C-spaces are exactly the C-compact spaces of Haver. The main results of the theory of weakly infinite-dimensional spaces, including classification via transfinite Lebesgue dimensions and Luzin-Sierpinsky indices, extend to these new classes of spaces. Weak m-C-spaces are characterised by means of essential maps to Henderson's m-compacta. The existence of hereditarily m-strongly infinite-dimensional spaces is proved.

  11. Physical model of dimensional regularization

    Energy Technology Data Exchange (ETDEWEB)

    Schonfeld, Jonathan F.

    2016-12-15

    We explicitly construct fractals of dimension 4-ε on which dimensional regularization approximates scalar-field-only quantum-field theory amplitudes. The construction does not require fractals to be Lorentz-invariant in any sense, and we argue that there probably is no Lorentz-invariant fractal of dimension greater than 2. We derive dimensional regularization's power-law screening first for fractals obtained by removing voids from 3-dimensional Euclidean space. The derivation applies techniques from elementary dielectric theory. Surprisingly, fractal geometry by itself does not guarantee the appropriate power-law behavior; boundary conditions at fractal voids also play an important role. We then extend the derivation to 4-dimensional Minkowski space. We comment on generalization to non-scalar fields, and speculate about implications for quantum gravity. (orig.)

  12. Three-dimensional biomedical imaging

    International Nuclear Information System (INIS)

    Robb, R.A.

    1985-01-01

    Scientists in biomedical imaging provide researchers, physicians, and academicians with an understanding of the fundamental theories and practical applications of three-dimensional biomedical imaging methodologies. Succinct descriptions of each imaging modality are supported by numerous diagrams and illustrations which clarify important concepts and demonstrate system performance in a variety of applications. Comparison of the different functional attributes, relative advantages and limitations, complementary capabilities, and future directions of three-dimensional biomedical imaging modalities are given. Volume 1: Introductions to Three-Dimensional Biomedical Imaging Photoelectronic-Digital Imaging for Diagnostic Radiology. X-Ray Computed Tomography - Basic Principles. X-Ray Computed Tomography - Implementation and Applications. X-Ray Computed Tomography: Advanced Systems and Applications in Biomedical Research and Diagnosis. Volume II: Single Photon Emission Computed Tomography. Position Emission Tomography (PET). Computerized Ultrasound Tomography. Fundamentals of NMR Imaging. Display of Multi-Dimensional Biomedical Image Information. Summary and Prognostications

  13. Myth and One-Dimensionality

    Directory of Open Access Journals (Sweden)

    William Hansen

    2017-12-01

    Full Text Available A striking difference between the folk-narrative genres of legend and folktale is how the human characters respond to supernatural, otherworldly, or uncanny beings such as ghosts, gods, dwarves, giants, trolls, talking animals, witches, and fairies. In legend the human actors respond with fear and awe, whereas in folktale they treat such beings as if they were ordinary and unremarkable. Since folktale humans treat all characters as belonging to a single realm, folklorists have described the world of the folktale as one-dimensional, in contrast to the two-dimensionality of the legend. The present investigation examines dimensionality in the third major genre of folk narrative: myth. Using the Greek and Hebrew myths of primordial paradise as sample narratives, the present essay finds—surprisingly—that the humans in these stories respond to the otherworldly one-dimensionally, as folktale characters do, and suggests an explanation for their behavior that is peculiar to the world of myth.

  14. A Four-Dimensional Approach

    African Journals Online (AJOL)

    ... of East Asian Students in English-speaking Countries: A Four-Dimensional ... country's language greatly shapes all aspects of the student's international education ... Taking this ecological approach will help clearly define the role that home ...

  15. Radiation Damage and Dimensional Changes

    International Nuclear Information System (INIS)

    El-Barbary, A.A.; Lebda, H.I.; Kamel, M.A.

    2009-01-01

    The dimensional changes have been modeled in order to be accommodated in the reactor design. This study has major implications for the interpretation of damage in carbon based nuclear fission and fusion plant materials. Radiation damage of graphite leads to self-interstitials and vacancies defects. The aggregation of these defects causes dimensional changes. Vacancies aggregate into lines and disks which heal and contract the basal planes. Interstitials aggregate into interlayer disks which expand the dimension

  16. Dimension reduction methods for microarray data: a review

    Directory of Open Access Journals (Sweden)

    Rabia Aziz

    2017-03-01

    Full Text Available Dimension reduction has become inevitable for pre-processing of high dimensional data. “Gene expression microarray data” is an instance of such high dimensional data. Gene expression microarray data displays the maximum number of genes (features simultaneously at a molecular level with a very small number of samples. The copious numbers of genes are usually provided to a learning algorithm for producing a complete characterization of the classification task. However, most of the times the majority of the genes are irrelevant or redundant to the learning task. It will deteriorate the learning accuracy and training speed as well as lead to the problem of overfitting. Thus, dimension reduction of microarray data is a crucial preprocessing step for prediction and classification of disease. Various feature selection and feature extraction techniques have been proposed in the literature to identify the genes, that have direct impact on the various machine learning algorithms for classification and eliminate the remaining ones. This paper describes the taxonomy of dimension reduction methods with their characteristics, evaluation criteria, advantages and disadvantages. It also presents a review of numerous dimension reduction approaches for microarray data, mainly those methods that have been proposed over the past few years.

  17. Fraction Reduction in Membrane Systems

    Directory of Open Access Journals (Sweden)

    Ping Guo

    2014-01-01

    Full Text Available Fraction reduction is a basic computation for rational numbers. P system is a new computing model, while the current methods for fraction reductions are not available in these systems. In this paper, we propose a method of fraction reduction and discuss how to carry it out in cell-like P systems with the membrane structure and the rules with priority designed. During the application of fraction reduction rules, synchronization is guaranteed by arranging some special objects in these rules. Our work contributes to performing the rational computation in P systems since the rational operands can be given in the form of fraction.

  18. Logistics Reduction: Heat Melt Compactor

    Data.gov (United States)

    National Aeronautics and Space Administration — The Advanced Exploration Systems (AES) Logistics Reduction (LR) project Heat Melt Compactor (HMC) technology is a waste management technology. Currently, there are...

  19. Nonlinear Model Reduction for RTCVD

    National Research Council Canada - National Science Library

    Newman, Andrew J; Krishnaprasad, P. S

    1998-01-01

    ...) for semiconductor manufacturing. They focus on model reduction for the ordinary differential equation model describing heat transfer to, from, and within a semiconductor wafer in the RTCVD chamber...

  20. Effects of applying three-dimensional seismic isolation system on the seismic design of FBR

    International Nuclear Information System (INIS)

    Hirata, Kazuta; Yabana, Shuichi; Kanazawa, Kenji; Matsuda, Akihiro

    1997-01-01

    In this study conceptional three-dimensional seismic isolation system for fast breeder reactor (FBR) is proposed. Effects of applying three-dimensional seismic isolation system on the seismic design for the FBR equipment are evaluated quantitatively. From the evaluation, it is concluded following effects are expected by applying the three-dimensional seismic isolation system to the FBR and the effects are evaluated quantitatively. (1) Reduction of membrane thickness of the reactor vessel (2) Suppression of uplift of fuels by reducing vertical seismic response of the core (3) Reduction of the supports for the piping system (4) Three-dimensional base isolation system for the whole reactor building is advantageous to the combined isolation system of horizontal base isolation for the reactor building and vertical isolation for the equipment. (author)

  1. Quantum Hamiltonian reduction and conformal field theories

    International Nuclear Information System (INIS)

    Bershadsky, M.

    1991-01-01

    It is proved that irreducible representation of the Virasoro algebra can be extracted from an irreducible representation space of the SL (2, R) current algebra by putting a constraint on the latter using the BRST formalism. Thus there is a SL(2, R) symmetry in the Virasoro algebra which is gauged and hidden. This construction of the Virasoro algebra is the quantum analog of the Hamiltonian reduction. The author then naturally leads to consider an SL(2, R) Wess-Zumino-Witten model. This system is related to the quantum field theory of the coadjoint orbit of the Virasoro group. Based on this result he presents the canonical derivation of the SL(2, R) current algebra in Polyakov's theory of two dimensional gravity; it is manifestation of the SL(2, R) symmetry in the conformal field theory hidden by the quantum Hamiltonian reduction. He discusses the quantum Hamiltonian reduction of the SL(n, R) current algebra for the general type of constraints labeled by index 1 ≤ l ≤ (n - 1) and claim that it leads to the new extended conformal algebras W n l . For l = 1 he recovers the well known W n algebra introduced by A. Zamolodchikov. For SL(3, R) Wess-Zumino-Witten model there are two different possibilities of constraining it. The first possibility gives the W 3 algebra, while the second leads to the new chiral algebra W 3 2 generated by the stress-energy tensor, two bosonic supercurrents with spins 3/2 and the U(1) current. He conjectures a Kac formula that describes the highly reducible representation for this algebra. He also makes some speculations concerning the structure of W gravity

  2. Low Dimensionality Effects in Complex Magnetic Oxides

    Science.gov (United States)

    Kelley, Paula J. Lampen

    Complex magnetic oxides represent a unique intersection of immense technological importance and fascinating physical phenomena originating from interwoven structural, electronic and magnetic degrees of freedom. The resulting energetically close competing orders can be controllably selected through external fields. Competing interactions and disorder represent an additional opportunity to systematically manipulate the properties of pure magnetic systems, leading to frustration, glassiness, and other novel phenomena while finite sample dimension plays a similar role in systems with long-range cooperative effects or large correlation lengths. A rigorous understanding of these effects in strongly correlated oxides is key to manipulating their functionality and device performance, but remains a challenging task. In this dissertation, we examine a number of problems related to intrinsic and extrinsic low dimensionality, disorder, and competing interactions in magnetic oxides by applying a unique combination of standard magnetometry techniques and unconventional magnetocaloric effect and transverse susceptibility measurements. The influence of dimensionality and disorder on the nature and critical properties of phase transitions in manganites is illustrated in La0.7 Ca0.3MnO3, in which both size reduction to the nanoscale and chemically-controlled quenched disorder are observed to induce a progressive weakening of the first-order nature of the transition, despite acting through the distinct mechanisms of surface effects and site dilution. In the second-order material La0.8Ca0.2MnO3, a strong magnetic field is found to drive the system toward its tricritical point as competition between exchange interactions in the inhomogeneous ground state is suppressed. In the presence of large phase separation stabilized by chemical disorder and long-range strain, dimensionality has a profound effect. With the systematic reduction of particle size in microscale-phase-separated (La, Pr

  3. Symmetry Analysis and Exact Solutions of (2+1)-Dimensional Sawada-Kotera Equation

    International Nuclear Information System (INIS)

    Zhi Hongyan; Zhang Hongqing

    2008-01-01

    Based on the symbolic computation system Maple, the infinite-dimensional symmetry group of the (2+1)-dimensional Sawada-Kotera equation is found by the classical Lie group method and the characterization of the group properties is given. The symmetry groups are used to perform the symmetry reduction. Moreover, with Lou's direct method that is based on Lax pairs, we obtain the symmetry transformations of the Sawada-Kotera and Konopelchenko-Dubrovsky equations, respectively.

  4. Green reduction of graphene oxide by ascorbic acid

    Science.gov (United States)

    Khosroshahi, Zahra; Kharaziha, Mahshid; Karimzadeh, Fathallah; Allafchian, Alireza

    2018-01-01

    Graphene, a single layer of sp2-hybridized carbon atoms in a hexagonal (two-dimensional honey-comb) lattice, has attracted strong scientific and technological interest due to its novel and excellent optical, chemical, electrical, mechanical and thermal properties. The solution-processable chemical reduction of Graphene oxide (GO is considered as the most favorable method regarding mass production of graphene. Generally, the reduction of GO is carried out by chemical approaches using different reductants such as hydrazine and sodium borohydride. These components are corrosive, combustible and highly toxic which may be dangerous for personnel health and the environment. Hence, these reducing agents are not promising choice for reducing of graphene oxide (GO). As a consequence, it is necessary for further development and optimization of eco-friendly, natural reducing agent for clean and effective reduction of GO. Ascorbic acid, an eco-friendly and natural reducing agents, having a mild reductive ability and nontoxic property. So, the aim of this research was to green synthesis of GO with ascorbic acid. For this purpose, the required amount of NaOH and ascorbic acid were added to GO solution (0.5 mg/ml) and were heated at 95 °C for 1 hour. According to the X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and electrochemical results, GO were reduced with ascorbic acid like hydrazine with better electrochemical properties and ascorbic acid is an ideal substitute for hydrazine in the reduction of graphene oxide process.

  5. Confluence reduction for probabilistic systems

    NARCIS (Netherlands)

    Timmer, Mark; van de Pol, Jan Cornelis; Stoelinga, Mariëlle Ida Antoinette

    In this presentation we introduce a novel technique for state space reduction of probabilistic specifications, based on a newly developed notion of confluence for probabilistic automata. We proved that this reduction preserves branching probabilistic bisimulation and can be applied on-the-fly. To

  6. Aircraft Noise Reduction Subproject Overview

    Science.gov (United States)

    Fernandez, Hamilton; Nark, Douglas M.; Van Zante, Dale E.

    2016-01-01

    The material presents highlights of propulsion and airframe noise research being completed for the Advanced Air Transport Technology Project. The basis of noise reduction plans along with representative work for the airframe, propulsion, and propulsion-airframe integration is discussed for the Aircraft Noise reduction Subproject.

  7. Casting light on harm reduction

    DEFF Research Database (Denmark)

    Jourdan, Michael

    2009-01-01

    Background: Harm reduction is commonly regarded as complementary to other drug problem responses - as the fourth tier. Yet even core examples of harm reduction such as the provision of injection equipment and methadone treatment has over and over encountered considerable opposition, and harm redu...

  8. Reduction of chemical reaction models

    Science.gov (United States)

    Frenklach, Michael

    1991-01-01

    An attempt is made to reconcile the different terminologies pertaining to reduction of chemical reaction models. The approaches considered include global modeling, response modeling, detailed reduction, chemical lumping, and statistical lumping. The advantages and drawbacks of each of these methods are pointed out.

  9. Comments on Beckmann's Uniform Reducts

    OpenAIRE

    Cook, Stephen

    2006-01-01

    Arnold Beckmann defined the uniform reduct of a propositional proof system f to be the set of those bounded arithmetical formulas whose propositional translations have polynomial size f-proofs. We prove that the uniform reduct of f + Extended Frege consists of all true bounded arithmetical formulas iff f + Extended Frege simulates every proof system.

  10. Chronic sleep reduction in adolescents

    NARCIS (Netherlands)

    Dewald-Kaufmann, J.F.

    2012-01-01

    Based on the results of this thesis, it can be concluded that sleep problems and chronic sleep reduction have a high impact on adolescents’ daytime functioning. Additionally, this research shows that gradual sleep extension can improve adolescents’ sleep and especially their chronic sleep reduction.

  11. Biochemistry of Catabolic Reductive Dehalogenation.

    Science.gov (United States)

    Fincker, Maeva; Spormann, Alfred M

    2017-06-20

    A wide range of phylogenetically diverse microorganisms couple the reductive dehalogenation of organohalides to energy conservation. Key enzymes of such anaerobic catabolic pathways are corrinoid and Fe-S cluster-containing, membrane-associated reductive dehalogenases. These enzymes catalyze the reductive elimination of a halide and constitute the terminal reductases of a short electron transfer chain. Enzymatic and physiological studies revealed the existence of quinone-dependent and quinone-independent reductive dehalogenases that are distinguishable at the amino acid sequence level, implying different modes of energy conservation in the respective microorganisms. In this review, we summarize current knowledge about catabolic reductive dehalogenases and the electron transfer chain they are part of. We review reaction mechanisms and the role of the corrinoid and Fe-S cluster cofactors and discuss physiological implications.

  12. Three dimensional MEMS supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei

    2011-10-15

    The overall objective of this research is to achieve compact supercapacitors with high capacitance, large power density, and long cycle life for using as micro power sources to drive low power devices and sensors. The main shortcoming of supercapacitors as a power source is that its energy density typically is about 1/10 of that of batteries. To achieve compact supercapacitors of large energy density, supercapacitors must be developed with high capacitance and power density which are mainly depended on the effective surface area of the electrodes of the supercapacitors. Many studies have been done to increase the effective surface area by modifying the electrode materials, however, much less investigations are focus on machining the electrodes. In my thesis work, micro- and nano-technologies are applied as technology approaches for machining the electrodes with three dimensional (3D) microstructures. More specific, Micro-electro-mechanical system (MEMS) fabrication process flow, which integrates the key process such as LIGA-like (German acronym for Lithographie, Galvanoformung, Abformung, which mean Lithography, Electroplating and Molding) technology or DRIE (deep reactive ion etching), has been developed to enable innovative designs of 3D MEMS supercapacitors which own the electrodes of significantly increased geometric area. Two types of 3D MEMS supercapcitors, based on LIGA-like and DRIE technology respectively, were designed and successfully created. The LIGA-like based 3D MEMS supercapacitor is with an interdigital 3D structure, and consists of silicon substrate, two electroplated nickel current collectors, two PPy (poly pyrrole) electrodes, and solid state electrolyte. The fabrication process flow developed includes the flowing key processes, SU-8 lithography, nickel electroplating, PPy polymerization and solid state electrolyte coating. Electrochemical tests showed that the single electrode of the supercapacitor has the specific capacitance of 0.058 F cm-2

  13. Determination of reduction yield of lithium metal reduction process

    International Nuclear Information System (INIS)

    Choi, In Kyu; Cho, Young Hwan; Kim, Taek Jin; Jee, Kwang Young

    2004-01-01

    Metal reduction of spent oxide fuel is the first step for the effective storage of spent fuel in Korea as well as transmutation purpose of long-lived radio-nuclides. During the reduction of uranium oxide by lithium metal to uranium metal, lithium oxide is stoichiometrically produced. By determining the concentration of lithium oxide in lithium chloride, we can estimate that how much uranium oxide is converted to uranium metal. Previous method to determine the lithium oxide concentration in lithium chloride is tedious and timing consuming. This paper describe the on-line monitoring method of lithium oxide during the reduction process

  14. Two-dimensional beam profiles and one-dimensional projections

    Science.gov (United States)

    Findlay, D. J. S.; Jones, B.; Adams, D. J.

    2018-05-01

    One-dimensional projections of improved two-dimensional representations of transverse profiles of particle beams are proposed for fitting to data from harp-type monitors measuring beam profiles on particle accelerators. Composite distributions, with tails smoothly matched on to a central (inverted) parabola, are shown to give noticeably better fits than single gaussian and single parabolic distributions to data from harp-type beam profile monitors all along the proton beam transport lines to the two target stations on the ISIS Spallation Neutron Source. Some implications for inferring beam current densities on the beam axis are noted.

  15. Three-dimensional oscillator and Coulomb systems reduced from Kaehler spaces

    International Nuclear Information System (INIS)

    Nersessian, Armen; Yeranyan, Armen

    2004-01-01

    We define the oscillator and Coulomb systems on four-dimensional spaces with U(2)-invariant Kaehler metric and perform their Hamiltonian reduction to the three-dimensional oscillator and Coulomb systems specified by the presence of Dirac monopoles. We find the Kaehler spaces with conic singularity, where the oscillator and Coulomb systems on three-dimensional sphere and two-sheet hyperboloid originate. Then we construct the superintegrable oscillator system on three-dimensional sphere and hyperboloid, coupled to a monopole, and find their four-dimensional origins. In the latter case the metric of configuration space is a non-Kaehler one. Finally, we extend these results to the family of Kaehler spaces with conic singularities

  16. Apparent destruction of superconductivity in the disordered one-dimensional limit

    International Nuclear Information System (INIS)

    Graybeal, J.M.; Mankiewich, P.M.; Dynes, R.C.; Beasley, M.R.

    1987-01-01

    We present the results of a model-system study of the competition between superconductivity and disorder in narrow superconducting wires. As one moves from the two-dimensional regime toward the one-dimensional limit, large and systematic reductions in the superconducting transition temperature are obtained. The observed behavior extrapolates to the total destruction of superconductivity in the disordered one-dimensional limit. Our findings are in clear disagreement with a recent theoretical treatment. In addition, the superconducting fluctuations appear to be modified by disorder for the narrowest samples

  17. Instability in near-horizon geometries of even-dimensional Myers–Perry black holes

    International Nuclear Information System (INIS)

    Tanahashi, Norihiro; Murata, Keiju

    2012-01-01

    We study the gravitational, electromagnetic and scalar field perturbations on the near-horizon geometries of the even-dimensional extremal Myers–Perry black holes. By dimensional reduction, the perturbation equations are reduced to effective equations of motion in AdS 2 . We find that some modes in the gravitational perturbations violate the Breitenlöhner–Freedman bound in AdS 2 . This result suggests that the even-dimensional (near-)extremal Myers–Perry black holes are unstable against gravitational perturbations. We also discuss implications of our results to the Kerr–CFT correspondence. (paper)

  18. Two-dimensional field theory description of a disoriented chiral condensate

    International Nuclear Information System (INIS)

    Kogan, I.I.

    1993-01-01

    We consider the effective (1+1)-dimensional chiral theory describing fluctuations of the order parameter of the disoriented chiral condensate (DCC) which can be formed in the central rapidity region in relativistic nucleus-nucleus or nucleon-nucleon collisions at high energy. Using (1+1)-dimensional reduction of QCD at high energies and assuming spin polarization of the DDC one can find the Wess-Zumino-Novikov-Witten model at the level k=3 as the effective chiral theory for the one-dimensional DDC. Some possible phenomenological consequences are briefly discussed

  19. Reentrant resistance and giant Andreev back scattering in a two-dimensional electron gas coupled to superconductors

    NARCIS (Netherlands)

    den Hartog, Sander; Wees, B.J. van; Nazarov, Yu.V.; Klapwijk, T.M.; Borghs, G.

    1998-01-01

    We first present the bias-voltage dependence of the superconducting phase-dependent reduction in the differential resistance of a disordered T-shaped two-dimensional electron gas (2DEG) coupled to two superconductors. This reduction exhibits a reentrant behavior, since it first increases upon

  20. (Weakly) three-dimensional caseology

    International Nuclear Information System (INIS)

    Pomraning, G.C.

    1996-01-01

    The singular eigenfunction technique of Case for solving one-dimensional planar symmetry linear transport problems is extended to a restricted class of three-dimensional problems. This class involves planar geometry, but with forcing terms (either boundary conditions or internal sources) which are weakly dependent upon the transverse spatial variables. Our analysis involves a singular perturbation about the classic planar analysis, and leads to the usual Case discrete and continuum modes, but modulated by weakly dependent three-dimensional spatial functions. These functions satisfy parabolic differential equations, with a different diffusion coefficient for each mode. Representative one-speed time-independent transport problems are solved in terms of these generalised Case eigenfunctions. Our treatment is very heuristic, but may provide an impetus for more rigorous analysis. (author)