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Sample records for recurrent multilayer perceptron

  1. Learning multilayer perceptrons efficiently

    OpenAIRE

    Bunzmann, C.; Biehl, M.; Urbanczik, R

    2001-01-01

    A learning algorithm for multilayer perceptrons is presented which is based on finding the principal components of a correlation matrix computed from the example inputs and their target outputs. For large networks our procedure needs far fewer examples to achieve good generalization than traditional on-line algorithms.

  2. KLASIFIKASI WEBSITE MENGGUNAKAN ALGORITMA MULTILAYER PERCEPTRON

    Directory of Open Access Journals (Sweden)

    Nyoman Purnama

    2014-12-01

    Full Text Available Sistem klasifikasi merupakan proses temu balik informasi yang sangat bergantung dari elemen-elemen penyusunnya.Sistem ini banyak digunakan untuk mengatasi permasalahan segmentasi data. Klasifikasi dapat digunakan pada website sebagaimetode untuk mengelompokkan website. Website merupakan salah satu data yang memiliki informasi yang beraneka-ragam,sehingga pengelompokan data ini penting untuk diteliti. Sistem klasifikasi dimulai dengan melakukan proses pengumpulaninformasi dari halaman website (parsing dan untuk setiap hasil parsing dilakukan proses penghapusan kata henti, stemming,feature selection dengan tf-idf. Hasil dari proses ini berupa fitur yang menjadi inputan algoritma Multilayer Perceptron. Dalamalgoritma ini terjadi proses pembelajaran terhadap pola input masukan dan pembuatan bobot pelatihan. Bobot ini akandigunakan pada proses klasifikasi. Hasil dari penelitian menunjukkan bahwa algoritma Multilayer Perceptron dapatmenghasilkan klasifikasi website dengan akurasi yang bagus. Hal ini dibuktikan dengan beberapa tahapan penelitian yangberbeda dan didapatkan nilai akurasi rata-rata diatas 70%.

  3. Quaternionic Multilayer Perceptron with Local Analyticity

    Directory of Open Access Journals (Sweden)

    Nobuyuki Matsui

    2012-11-01

    Full Text Available A multi-layered perceptron type neural network is presented and analyzed in this paper. All neuronal parameters such as input, output, action potential and connection weight are encoded by quaternions, which are a class of hypercomplex number system. Local analytic condition is imposed on the activation function in updating neurons’ states in order to construct learning algorithm for this network. An error back-propagation algorithm is introduced for modifying the connection weights of the network.

  4. Extreme Learning Machine for Multilayer Perceptron.

    Science.gov (United States)

    Tang, Jiexiong; Deng, Chenwei; Huang, Guang-Bin

    2016-04-01

    Extreme learning machine (ELM) is an emerging learning algorithm for the generalized single hidden layer feedforward neural networks, of which the hidden node parameters are randomly generated and the output weights are analytically computed. However, due to its shallow architecture, feature learning using ELM may not be effective for natural signals (e.g., images/videos), even with a large number of hidden nodes. To address this issue, in this paper, a new ELM-based hierarchical learning framework is proposed for multilayer perceptron. The proposed architecture is divided into two main components: 1) self-taught feature extraction followed by supervised feature classification and 2) they are bridged by random initialized hidden weights. The novelties of this paper are as follows: 1) unsupervised multilayer encoding is conducted for feature extraction, and an ELM-based sparse autoencoder is developed via l1 constraint. By doing so, it achieves more compact and meaningful feature representations than the original ELM; 2) by exploiting the advantages of ELM random feature mapping, the hierarchically encoded outputs are randomly projected before final decision making, which leads to a better generalization with faster learning speed; and 3) unlike the greedy layerwise training of deep learning (DL), the hidden layers of the proposed framework are trained in a forward manner. Once the previous layer is established, the weights of the current layer are fixed without fine-tuning. Therefore, it has much better learning efficiency than the DL. Extensive experiments on various widely used classification data sets show that the proposed algorithm achieves better and faster convergence than the existing state-of-the-art hierarchical learning methods. Furthermore, multiple applications in computer vision further confirm the generality and capability of the proposed learning scheme. PMID:25966483

  5. Wind speed estimation using multilayer perceptron

    International Nuclear Information System (INIS)

    Highlights: • We present a method for determining the average wind speed using neural networks. • We use data from that site in the short term and data from other nearby stations. • The inputs used in the ANN were wind speed and direction data from a station. • The method allows knowing the wind speed without topographical data. - Abstract: Wind speed knowledge is prerequisite in the siting of wind turbines. In consequence the wind energy use requires meticulous and specified knowledge of the wind characteristics at a location. This paper presents a method for determining the annual average wind speed at a complex terrain site by using neural networks, when only short term data are available for that site. This information is useful for preliminary calculations of the wind resource at a remote area having only a short time period of wind measurements measurement in a site. Artificial neural networks are useful for implementing non-linear process variables over time, and therefore are a useful tool for estimating the wind speed. The neural network used is multilayer perceptron with three layers and the supervised learning algorithm used is backpropagation. The inputs used in the neural network were wind speed and direction data from a single station, and the training patterns used correspond to sixty days data. The results obtained by simulating the annual average wind speed at the selected site based on data from nearby stations with correlation coefficients above 0.5 were satisfactory, compared with actual values. Reliable estimations were obtained, with errors below 6%

  6. Prediction of Parametric Roll Resonance by Multilayer Perceptron Neural Network

    DEFF Research Database (Denmark)

    Míguez González, M; López Peña, F.; Díaz Casás, V.; Galeazzi, Roberto; Blanke, Mogens

    acknowledged in the last few years. This work proposes a prediction system based on a multilayer perceptron (MP) neural network. The training and testing of the MP network is accomplished by feeding it with simulated data of a three degrees-of-freedom nonlinear model of a fishing vessel. The neural network is...

  7. Newton's Method Backpropagation for Complex-Valued Holomorphic Multilayer Perceptrons

    OpenAIRE

    La Corte, Diana Thomson; Zou, Yi Ming

    2014-01-01

    The study of Newton's method in complex-valued neural networks faces many difficulties. In this paper, we derive Newton's method backpropagation algorithms for complex-valued holomorphic multilayer perceptrons, and investigate the convergence of the one-step Newton steplength algorithm for the minimization of real-valued complex functions via Newton's method. To provide experimental support for the use of holomorphic activation functions, we perform a comparison of using sigmoidal functions v...

  8. Validation of Infinite Impulse Response Multilayer Perceptron for Modelling Nuclear Dynamics

    Directory of Open Access Journals (Sweden)

    N. Pedroni

    2008-03-01

    Full Text Available Artificial neural networks are powerful algorithms for constructing nonlinear empirical models from operational data. Their use is becoming increasingly popular in the complex modeling tasks required by diagnostic, safety, and control applications in complex technologies such as those employed in the nuclear industry. In this paper, the nonlinear modeling capabilities of an infinite impulse response multilayer perceptron (IIR-MLP for nuclear dynamics are considered in comparison to static modeling by a finite impulse response multilayer perceptron (FIR-MLP and a conventional static MLP. The comparison is made with respect to the nonlinear dynamics of a nuclear reactor as investigated by IIR-MLP in a previous paper. The superior performance of the locally recurrent scheme is demonstrated.

  9. Validation of Infinite Impulse Response Multilayer Perceptron for Modelling Nuclear Dynamics

    International Nuclear Information System (INIS)

    Artificial neural networks are powerful algorithms for constructing nonlinear empirical models from operational data. Their use is becoming increasingly popular in the complex modeling tasks required by diagnostic, safety, and control applications in complex technologies such as those employed in the nuclear industry. In this paper, the nonlinear modeling capabilities of an infinite impulse response multilayer perceptron (IIR-MLP) for nuclear dynamics are considered in comparison to static modeling by a finite impulse response multilayer perceptron (FIR-MLP) and a conventional static MLP. The comparison is made with respect to the nonlinear dynamics of a nuclear reactor as investigated by IIR-MLP in a previous paper. The superior performance of the locally recurrent scheme is demonstrated

  10. A Parallel Framework for Multilayer Perceptron for Human Face Recognition

    CERN Document Server

    Bhowmik, M K; Nasipuri, M; Basu, D K; Kundu, M

    2010-01-01

    Artificial neural networks have already shown their success in face recognition and similar complex pattern recognition tasks. However, a major disadvantage of the technique is that it is extremely slow during training for larger classes and hence not suitable for real-time complex problems such as pattern recognition. This is an attempt to develop a parallel framework for the training algorithm of a perceptron. In this paper, two general architectures for a Multilayer Perceptron (MLP) have been demonstrated. The first architecture is All-Class-in-One-Network (ACON) where all the classes are placed in a single network and the second one is One-Class-in-One-Network (OCON) where an individual single network is responsible for each and every class. Capabilities of these two architectures were compared and verified in solving human face recognition, which is a complex pattern recognition task where several factors affect the recognition performance like pose variations, facial expression changes, occlusions, and ...

  11. Learning of Multilayer Perceptrons with Piecewise-Linear Activation Functions

    Czech Academy of Sciences Publication Activity Database

    Kozub, P.; Holeňa, Martin

    Praha : Matfyzpress, 2008 - (Obdržálek, D.; Štanclová, J.; Plátek, M.), s. 27-46 ISBN 978-80-7378-076-0. [ MIS 2008. Malý informatický seminář /25./. Josefův důl (CZ), 12.01.2008-19.01.2008] R&D Projects: GA ČR GA201/08/0802; GA ČR GA201/08/1744 Institutional research plan: CEZ:AV0Z10300504 Keywords : artificial neural networks * multilayer perceptrons * activation functions * function approximation * constrained optimization Subject RIV: IN - Informatics, Computer Science

  12. A Choice of Input Variables for a Multilayer Perceptron

    International Nuclear Information System (INIS)

    In the paper some aspects of multilayer perceptron (MLP) application to the problem of classifying the events presented by empirical samples of a finite volume are considered. The results of the MLP learning for various forms of the input data are analyzed and the reasons leading to the effect of an instantaneous learning of the MLP and rise of the neural network are investigated for the case when the input data are presented in a form of variational series. The problem of hidden layer neuron reduction without raising the recognition error is discussed. (author). 13 refs., 6 figs., 1 tab

  13. Multilayer Perceptron for Prediction of 2006 World Cup Football Game

    OpenAIRE

    Kou-Yuan Huang; Kai-Ju Chen

    2011-01-01

    Multilayer perceptron (MLP) with back-propagation learning rule is adopted to predict the winning rates of two teams according to their official statistical data of 2006 World Cup Football Game at the previous stages. There are training samples from three classes: win, draw, and loss. At the new stage, new training samples are selected from the previous stages and are added to the training samples, then we retrain the neural network. It is a type of on-line learning. The 8 features are select...

  14. Training trajectories by continuous recurrent multilayer networks.

    Science.gov (United States)

    Leistritz, L; Galicki, M; Witte, H; Kochs, E

    2002-01-01

    This paper addresses the problem of training trajectories by means of continuous recurrent neural networks whose feedforward parts are multilayer perceptrons. Such networks can approximate a general nonlinear dynamic system with arbitrary accuracy. The learning process is transformed into an optimal control framework where the weights are the controls to be determined. A training algorithm based upon a variational formulation of Pontryagin's maximum principle is proposed for such networks. Computer examples demonstrating the efficiency of the given approach are also presented. PMID:18244431

  15. Key Generation and Certification using Multilayer Perceptron in Wireless communication(KGCMLP)

    OpenAIRE

    Sarkar, Arindam; Mandal, J. K.

    2012-01-01

    In this paper, a key generation and certification technique using multilayer perceptron (KGCMLP) has been proposed in wireless communication of data/information. In this proposed KGCMLP technique both sender and receiver uses an identical multilayer perceptrons. Both perceptrons are start synchronization by exchanging some control frames. During synchronization process message integrity test and synchronization test has been carried out. Only the synchronization test does not guarantee the se...

  16. Dynamics of learning in multilayer perceptrons near singularities.

    Science.gov (United States)

    Cousseau, Florent; Ozeki, Tomoko; Amari, Shun-Ichi

    2008-08-01

    The dynamical behavior of learning is known to be very slow for the multilayer perceptron, being often trapped in the "plateau." It has been recently understood that this is due to the singularity in the parameter space of perceptrons, in which trajectories of learning are drawn. The space is Riemannian from the point of view of information geometry and contains singular regions where the Riemannian metric or the Fisher information matrix degenerates. This paper analyzes the dynamics of learning in a neighborhood of the singular regions when the true teacher machine lies at the singularity. We give explicit asymptotic analytical solutions (trajectories) both for the standard gradient (SGD) and natural gradient (NGD) methods. It is clearly shown, in the case of the SGD method, that the plateau phenomenon appears in a neighborhood of the critical regions, where the dynamical behavior is extremely slow. The analysis of the NGD method is much more difficult, because the inverse of the Fisher information matrix diverges. We conquer the difficulty by introducing the "blow-down" technique used in algebraic geometry. The NGD method works efficiently, and the state converges directly to the true parameters very quickly while it staggers in the case of the SGD method. The analytical results are compared with computer simulations, showing good agreement. The effects of singularities on learning are thus qualitatively clarified for both standard and NGD methods. PMID:18701364

  17. Theoretical Properties of Projection Based Multilayer Perceptrons with Functional Inputs

    CERN Document Server

    Rossi, F; Rossi, Fabrice; Conan-Guez, Brieuc

    2006-01-01

    Many real world data are sampled functions. As shown by Functional Data Analysis (FDA) methods, spectra, time series, images, gesture recognition data, etc. can be processed more efficiently if their functional nature is taken into account during the data analysis process. This is done by extending standard data analysis methods so that they can apply to functional inputs. A general way to achieve this goal is to compute projections of the functional data onto a finite dimensional sub-space of the functional space. The coordinates of the data on a basis of this sub-space provide standard vector representations of the functions. The obtained vectors can be processed by any standard method. In our previous work, this general approach has been used to define projection based Multilayer Perceptrons (MLPs) with functional inputs. We study in this paper important theoretical properties of the proposed model. We show in particular that MLPs with functional inputs are universal approximators: they can approximate to ...

  18. Classification of fused face images using multilayer perceptron neural network

    CERN Document Server

    Bhattacharjee, Debotosh; Nasipuri, Mita; Basu, Dipak Kumar; Kundu, Mahantapas

    2010-01-01

    This paper presents a concept of image pixel fusion of visual and thermal faces, which can significantly improve the overall performance of a face recognition system. Several factors affect face recognition performance including pose variations, facial expression changes, occlusions, and most importantly illumination changes. So, image pixel fusion of thermal and visual images is a solution to overcome the drawbacks present in the individual thermal and visual face images. Fused images are projected into eigenspace and finally classified using a multi-layer perceptron. In the experiments we have used Object Tracking and Classification Beyond Visible Spectrum (OTCBVS) database benchmark thermal and visual face images. Experimental results show that the proposed approach significantly improves the verification and identification performance and the success rate is 95.07%. The main objective of employing fusion is to produce a fused image that provides the most detailed and reliable information. Fusion of multip...

  19. Online learning dynamics of multilayer perceptrons with unidentifiable parameters

    International Nuclear Information System (INIS)

    In the over-realizable learning scenario of multilayer perceptrons, in which the student network has a larger number of hidden units than the true or optimal network, some of the weight parameters are unidentifiable. In this case, the teacher network consists of a union of optimal subspaces included in the parameter space. The optimal subspaces, which lead to singularities, are known to affect the estimation performance of neural networks. Using statistical mechanics, we investigate the online learning dynamics of two-layer neural networks in the over-realizable scenario with unidentifiable parameters. We show that the convergence speed strongly depends on the initial parameter conditions. We also show that there is a quasi-plateau around the optimal subspace, which differs from the well-known plateaus caused by permutation symmetry. In addition, we discuss the property of the final learning state, relating this to the singular structures

  20. Power grid higher-order harmonics estimation with multilayer perceptrons

    Science.gov (United States)

    Nguyen, Thien Minh; Wira, Patrice

    2015-12-01

    This work proposes a new neural approach based on the structure of a Multi-Layer Perceptron (MLP) for identifying current harmonics in power systems. The learning approach is based on several MLP, adopts the Fourier decomposition of a signal and a training set generated from harmonic waveforms is used to calculate the weights. After training, each MLP is able to identify two coefficients for each harmonic term of the input signal. The effectiveness of the new approach is evaluated by experiments. Results show that the proposed MLPs of the new approach enable to identify effectively the amplitudes of harmonic terms from the signals under noisy condition. Results are compared to other and recent MLP approaches. The new approach can be applied in harmonic compensation strategies by being implement in an active power filter to ensure the power quality in electrical power systems.

  1. Optical proximity correction using a multilayer perceptron neural network

    Science.gov (United States)

    Luo, Rui

    2013-07-01

    Optical proximity correction (OPC) is one of the resolution enhancement techniques (RETs) in optical lithography, where the mask pattern is modified to improve the output pattern fidelity. Algorithms are needed to generate the modified mask pattern automatically and efficiently. In this paper, a multilayer perceptron (MLP) neural network (NN) is used to synthesize the mask pattern. We employ the pixel-based approach in this work. The MLP takes the pixel values of the desired output wafer pattern as input, and outputs the optimal mask pixel values. The MLP is trained with the backpropagation algorithm, with a training set retrieved from the desired output pattern, and the optimal mask pattern obtained by the model-based method. After training, the MLP is able to generate the optimal mask pattern non-iteratively with good pattern fidelity.

  2. Optical proximity correction using a multilayer perceptron neural network

    International Nuclear Information System (INIS)

    Optical proximity correction (OPC) is one of the resolution enhancement techniques (RETs) in optical lithography, where the mask pattern is modified to improve the output pattern fidelity. Algorithms are needed to generate the modified mask pattern automatically and efficiently. In this paper, a multilayer perceptron (MLP) neural network (NN) is used to synthesize the mask pattern. We employ the pixel-based approach in this work. The MLP takes the pixel values of the desired output wafer pattern as input, and outputs the optimal mask pixel values. The MLP is trained with the backpropagation algorithm, with a training set retrieved from the desired output pattern, and the optimal mask pattern obtained by the model-based method. After training, the MLP is able to generate the optimal mask pattern non-iteratively with good pattern fidelity. (paper)

  3. Forecasting PM10 in Algiers: efficacy of multilayer perceptron networks.

    Science.gov (United States)

    Abderrahim, Hamza; Chellali, Mohammed Reda; Hamou, Ahmed

    2016-01-01

    Air quality forecasting system has acquired high importance in atmospheric pollution due to its negative impacts on the environment and human health. The artificial neural network is one of the most common soft computing methods that can be pragmatic for carving such complex problem. In this paper, we used a multilayer perceptron neural network to forecast the daily averaged concentration of the respirable suspended particulates with aerodynamic diameter of not more than 10 μm (PM10) in Algiers, Algeria. The data for training and testing the network are based on the data sampled from 2002 to 2006 collected by SAMASAFIA network center at El Hamma station. The meteorological data, air temperature, relative humidity, and wind speed, are used as inputs network parameters in the formation of model. The training patterns used correspond to 41 days data. The performance of the developed models was evaluated on the basis index of agreement and other statistical parameters. It was seen that the overall performance of model with 15 neurons is better than the ones with 5 and 10 neurons. The results of multilayer network with as few as one hidden layer and 15 neurons were quite reasonable than the ones with 5 and 10 neurons. Finally, an error around 9% has been reached. PMID:26381787

  4. Ground Radar Target Classification Using Singular Value Decomposition and Multilayer Perceptron

    OpenAIRE

    I. Mokris; J. Kurty; Z. Matousek

    2001-01-01

    The paper deals with classification of ground radar targets. Areceived radar signal backscattered from a ground radar target wasdigitized and in the form of radar signal matrix utilized for a featureextraction based on Singular Value Decomposition. Furthermore, singularvalues of a backscattered radar signal matrix, as a target feature,were utilized for Radar Target Classification by multilayer perceptron.In the learning phase of a multilayer perceptron we used the learningtarget set and in th...

  5. Asymptotic law of likelihood ratio for multilayer perceptron models

    CERN Document Server

    Rynkiewicz, Joseph

    2010-01-01

    We consider regression models involving multilayer perceptrons (MLP) with one hidden layer and a Gaussian noise. The data are assumed to be generated by a true MLP model and the estimation of the parameters of the MLP is done by maximizing the likelihood of the model. When the number of hidden units of the true model is known, the asymptotic distribution of the maximum likelihood estimator (MLE) and the likelihood ratio (LR) statistic is easy to compute and converge to a $\\chi^2$ law. However, if the number of hidden unit is over-estimated the Fischer information matrix of the model is singular and the asymptotic behavior of the MLE is unknown. This paper deals with this case, and gives the exact asymptotic law of the LR statistics. Namely, if the parameters of the MLP lie in a suitable compact set, we show that the LR statistics is the supremum of the square of a Gaussian process indexed by a class of limit score functions.

  6. Classification of Log-Polar-Visual Eigenfaces using Multilayer Perceptron

    CERN Document Server

    Bhowmik, Mrinal Kanti; Nasipuri, Mita; Kundu, Mahantapas; Basu, Dipak Kumar

    2010-01-01

    In this paper we present a simple novel approach to tackle the challenges of scaling and rotation of face images in face recognition. The proposed approach registers the training and testing visual face images by log-polar transformation, which is capable to handle complicacies introduced by scaling and rotation. Log-polar images are projected into eigenspace and finally classified using an improved multi-layer perceptron. In the experiments we have used ORL face database and Object Tracking and Classification Beyond Visible Spectrum (OTCBVS) database for visual face images. Experimental results show that the proposed approach significantly improves the recognition performances from visual to log-polar-visual face images. In case of ORL face database, recognition rate for visual face images is 89.5% and that is increased to 97.5% for log-polar-visual face images whereas for OTCBVS face database recognition rate for visual images is 87.84% and 96.36% for log-polar-visual face images.

  7. [Research on Early Identification of Bipolar Disorder Based on Multi-layer Perceptron Neural Network].

    Science.gov (United States)

    Zhang, Haowei; Gao, Yanni; Yuan, Chengmei; Liu, Ying; Ding, Yuqing

    2015-06-01

    Multi-layer perceptron (MLP) neural network belongs to multi-layer feedforward neural network, and has the ability and characteristics of high intelligence. It can realize the complex nonlinear mapping by its own learning through the network. Bipolar disorder is a serious mental illness with high recurrence rate, high self-harm rate and high suicide rate. Most of the onset of the bipolar disorder starts with depressive episode, which can be easily misdiagnosed as unipolar depression and lead to a delayed treatment so as to influence the prognosis. The early identifica- tion of bipolar disorder is of great importance for patients with bipolar disorder. Due to the fact that the process of early identification of bipolar disorder is nonlinear, we in this paper discuss the MLP neural network application in early identification of bipolar disorder. This study covered 250 cases, including 143 cases with recurrent depression and 107 cases with bipolar disorder, and clinical features were statistically analyzed between the two groups. A total of 42 variables with significant differences were screened as the input variables of the neural network. Part of the samples were randomly selected as the learning sample, and the other as the test sample. By choosing different neu- ral network structures, all results of the identification of bipolar disorder were relatively good, which showed that MLP neural network could be used in the early identification of bipolar disorder. PMID:26485974

  8. Application of multilayer perceptron for prediction of radionuclide migration from catchment area to watercourse

    International Nuclear Information System (INIS)

    In the thesis the results of verification of multilayer perceptron (MLP) {20–41–1} application with sigmoid activation function for prediction of lateral radionuclide migration are presented. The calculated values of Cs 137 and Sr 90 volumetric activity are close to experimental measurement limits, indicating the possibility of MLP application for the solving problem. (authors)

  9. Evolutionary Learning of Multi-Layer Perceptron Neural Networks

    Czech Academy of Sciences Publication Activity Database

    Neruda, Roman; Slušný, Stanislav

    Košice : Prírodovedecká fakulta, Univerzita P. J. Šafárika, 2006 - (Vojtáš, P.), s. 125-130 ISBN 80-969184-4-3. [ITAT 2006. Workshop on Theory and Practice of Information Theory. Bystrá dolina (SK), 26.09.2006-01.10.2006] R&D Projects: GA AV ČR 1ET100300419 Institutional research plan: CEZ:AV0Z10300504 Keywords : perceptron networks * learning * evolutionary algorithms Subject RIV: IN - Informatics, Computer Science

  10. Second-Order Learning Methods for a Multilayer Perceptron

    International Nuclear Information System (INIS)

    First- and second-order learning methods for feed-forward multilayer neural networks are studied. Newton-type and quasi-Newton algorithms are considered and compared with commonly used back-propagation algorithm. It is shown that, although second-order algorithms require enhanced computer facilities, they provide better convergence and simplicity in usage. 13 refs., 2 figs., 2 tabs

  11. Query-based learning applied to partially trained multilayer perceptrons.

    Science.gov (United States)

    Hwang, J N; Choi, J J; Oh, S; Marks, R J

    1991-01-01

    An approach is presented for query-based neural network learning. A layered perceptron partially trained for binary classification is considered. The single-output neuron is trained to be either a zero or a one. A test decision is made by thresholding the output at, for example, one-half. The set of inputs that produce an output of one-half forms the classification boundary. The authors adopted an inversion algorithm for the neural network that allows generation of this boundary. For each boundary point, the classification gradient can be generated. The gradient provides a useful measure of the steepness of the multidimensional decision surfaces. Conjugate input pairs are generated using the boundary point and gradient information and presented to an oracle for proper classification. These data are used to refine further the classification boundary, thereby increasing the classification accuracy. The result can be a significant reduction in the training set cardinality in comparison with, for example, randomly generated data points. An application example to power system security assessment is given. PMID:18276359

  12. Classification of non-performing loans portfolio using Multilayer Perceptron artificial neural networks

    Directory of Open Access Journals (Sweden)

    Flávio Clésio Silva de Souza

    2014-06-01

    Full Text Available The purpose of the present research is to apply a Multilayer Perceptron (MLP neural network technique to create classification models from a portfolio of Non-Performing Loans (NPLs to classify this type of credit derivative. These credit derivatives are characterized as the amount of loans that were not paid and are already overdue more than 90 days. Since these titles are, because of legislative motives, moved by losses, Credit Rights Investment Funds (FDIC performs the purchase of these debts and the recovery of the credits. Using the Multilayer Perceptron (MLP architecture of Artificial Neural Network (ANN, classification models regarding the posterior recovery of these debts were created. To evaluate the performance of the models, evaluation metrics of classification relating to the neural networks with different architectures were presented. The results of the classifications were satisfactory, given the classification models were successful in the presented economics costs structure.

  13. Photometric redshifts with the Multilayer Perceptron Neural Network: application to the HDF-S and SDSS

    OpenAIRE

    Vanzella, E.; Cristiani, S.; Fontana, A.; M. Nonino(INAF/OAT); Arnouts, S.; Giallongo, E.; Grazian, A.; Fasano, G.; Popesso, P.; Saracco, P.; Zaggia, S.

    2003-01-01

    We present a technique for the estimation of photometric redshifts based on feed-forward neural networks. The Multilayer Perceptron (MLP) Artificial Neural Network is used to predict photometric redshifts in the HDF-S from an ultra deep multicolor catalog. Various possible approaches for the training of the neural network are explored, including the deepest and most complete spectroscopic redshift catalog currently available (the Hubble Deep Field North dataset) and models of the spectral ene...

  14. Optimal Parameter for the Training of Multilayer Perceptron Neural Networks by Using Hierarchical Genetic Algorithm

    International Nuclear Information System (INIS)

    This paper deals with the controversial topic of the selection of the parameters of a genetic algorithm, in this case hierarchical, used for training of multilayer perceptron neural networks for the binary classification. The parameters to select are the crossover and mutation probabilities of the control and parametric genes and the permanency percent. The results can be considered as a guide for using this kind of algorithm.

  15. Experiments with Evolutionary and Hybrid Learning of Multi-layer Perceptron Neural Networks

    Czech Academy of Sciences Publication Activity Database

    Neruda, Roman; Slušný, Stanislav

    Ostrava : VŠB Technická univerzita, 2007 - (Mikulecký, P.; Dvorský, J.; Krátký, M.), s. 75-84 ISBN 978-80-248-1279-3. [Znalosti 2007. Ostrava (CZ), 21.02.2007-23.02.2007] R&D Projects: GA AV ČR 1ET100300414 Institutional research plan: CEZ:AV0Z10300504 Keywords : multilayer perceptron * evolutionary learning * hybrid algorithms Subject RIV: IN - Informatics, Computer Science

  16. Fault Classification in Cylinders Using Multilayer Perceptrons, Support Vector Machines and Guassian Mixture Models

    CERN Document Server

    Marwala, Tshilidzi; Chakraverty, Snehashish

    2007-01-01

    Gaussian mixture models (GMM) and support vector machines (SVM) are introduced to classify faults in a population of cylindrical shells. The proposed procedures are tested on a population of 20 cylindrical shells and their performance is compared to the procedure, which uses multi-layer perceptrons (MLP). The modal properties extracted from vibration data are used to train the GMM, SVM and MLP. It is observed that the GMM produces 98%, SVM produces 94% classification accuracy while the MLP produces 88% classification rates.

  17. Siamese Multi-layer Perceptrons for Dimensionality Reduction and Face Identification

    OpenAIRE

    Zheng, Lilei; Duffner, Stefan; Idrissi, Khalid; Garcia, Christophe; Baskurt, Atilla

    2015-01-01

    This paper presents a framework using siamese Multi-layer Percep-trons (MLP) for supervised dimensionality reduction and face identification. Compared with the classical MLP that trains on fully labeled data, the siamese MLP learns on side information only, i.e., how similar of data examples are to each other. In this study, we compare it with the classical MLP on the problem of face identification. Experimental results on the Extended Yale B database demonstrate that the siamese MLP training...

  18. Multilayer perceptron and regression modelling to forecast hourly nitrogen dioxide concentrations

    OpenAIRE

    Capilla, Carmen

    2014-01-01

    This paper presents the application of feed-forward multilayer perceptron networks and multiple regression models, to forecast hourly nitrogen dioxide levels 24 hours in advance. Input data are traffic and meteorological variables, and nitrogen dioxide hourly levels. The introduction of four periodic components (sine and cosine terms for the daily and weekly cycles), and nitrogen oxide hourly levels was analyzed in order to improve the prediction power. The data were measure...

  19. A multilayer perceptron solution to the match phase problem in rule-based artificial intelligence systems

    Science.gov (United States)

    Sartori, Michael A.; Passino, Kevin M.; Antsaklis, Panos J.

    1992-01-01

    In rule-based AI planning, expert, and learning systems, it is often the case that the left-hand-sides of the rules must be repeatedly compared to the contents of some 'working memory'. The traditional approach to solve such a 'match phase problem' for production systems is to use the Rete Match Algorithm. Here, a new technique using a multilayer perceptron, a particular artificial neural network model, is presented to solve the match phase problem for rule-based AI systems. A syntax for premise formulas (i.e., the left-hand-sides of the rules) is defined, and working memory is specified. From this, it is shown how to construct a multilayer perceptron that finds all of the rules which can be executed for the current situation in working memory. The complexity of the constructed multilayer perceptron is derived in terms of the maximum number of nodes and the required number of layers. A method for reducing the number of layers to at most three is also presented.

  20. Empirical model development and validation with dynamic learning in the recurrent multilayer perception

    International Nuclear Information System (INIS)

    A nonlinear multivariable empirical model is developed for a U-tube steam generator using the recurrent multilayer perceptron network as the underlying model structure. The recurrent multilayer perceptron is a dynamic neural network, very effective in the input-output modeling of complex process systems. A dynamic gradient descent learning algorithm is used to train the recurrent multilayer perceptron, resulting in an order of magnitude improvement in convergence speed over static learning algorithms. In developing the U-tube steam generator empirical model, the effects of actuator, process,and sensor noise on the training and testing sets are investigated. Learning and prediction both appear very effective, despite the presence of training and testing set noise, respectively. The recurrent multilayer perceptron appears to learn the deterministic part of a stochastic training set, and it predicts approximately a moving average response. Extensive model validation studies indicate that the empirical model can substantially generalize (extrapolate), though online learning becomes necessary for tracking transients significantly different than the ones included in the training set and slowly varying U-tube steam generator dynamics. In view of the satisfactory modeling accuracy and the associated short development time, neural networks based empirical models in some cases appear to provide a serious alternative to first principles models. Caution, however, must be exercised because extensive on-line validation of these models is still warranted

  1. Apply Multi-Layer Perceptrons Neural Network for Off-Line Signature Verification and Recognition

    Directory of Open Access Journals (Sweden)

    Suhail Odeh

    2011-11-01

    Full Text Available This paper discusses the applying of Multi-layer perceptrons for signature verification and recognition using a new approach enables the user to recognize whether a signature is original or a fraud. The approach starts by scanning images into the computer, then modifying their quality through image enhancement and noise reduction, followed by feature extraction and neural network training, and finally verifies the authenticity of the signature. The paper discusses the different stages of the process including: image pre-processing, feature extraction and pattern recognition through neural networks.

  2. Experts Fusion and Multilayer Perceptron Based on Belief Learning for Sonar Image Classification

    CERN Document Server

    Martin, Arnaud

    2008-01-01

    The sonar images provide a rapid view of the seabed in order to characterize it. However, in such as uncertain environment, real seabed is unknown and the only information we can obtain, is the interpretation of different human experts, sometimes in conflict. In this paper, we propose to manage this conflict in order to provide a robust reality for the learning step of classification algorithms. The classification is conducted by a multilayer perceptron, taking into account the uncertainty of the reality in the learning stage. The results of this seabed characterization are presented on real sonar images.

  3. Multilayered perceptron neural networks to compute energy losses in magnetic cores

    International Nuclear Information System (INIS)

    This paper presents a new approach based on multilayered perceptrons (MLPs) to compute the specific energy losses of toroidal wound cores built from 3% SiFe 0.27 mm thick M4, 0.1 and 0.08 mm thin gauge electrical steel strips. The MLP has been trained by a back-propagation and extended delta-bar-delta learning algorithm. The results obtained by using the MLP model were compared with a commonly used conventional method. The comparison has shown that the proposed model improved loss estimation with respect to the conventional method

  4. Functional Multi-Layer Perceptron: a Nonlinear Tool for Functional Data Analysis

    CERN Document Server

    Rossi, Fabrice

    2005-01-01

    In this paper, we study a natural extension of Multi-Layer Perceptrons (MLP) to functional inputs. We show that fundamental results for classical MLP can be extended to functional MLP. We obtain universal approximation results that show the expressive power of functional MLP is comparable to that of numerical MLP. We obtain consistency results which imply that the estimation of optimal parameters for functional MLP is statistically well defined. We finally show on simulated and real world data that the proposed model performs in a very satisfactory way.

  5. Generation of hourly irradiation synthetic series using the neural network multilayer perceptron

    Energy Technology Data Exchange (ETDEWEB)

    Hontoria, L.; Aguilera, J. [Universidad de Jaen, Linares-Jaen (Spain). Dpto. de Electronica; Zufiria, P. [Ciudad Universitaria, Madrid (Spain). Grupo de Redes Neuronales

    2002-05-01

    In this work, a methodology based on the neural network model called multilayer perceptron (MLP) to solve a typical problem in solar energy is presented. This methodology consists of the generation of synthetic series of hourly solar irradiation. The model presented is based on the capacity of the MLP for finding relations between variables for which interrelation is unknown explicitly. The information available can be included progressively at the series generator at different stages. A comparative study with other solar irradiation synthetic generation methods has been done in order to demonstrate the validity of the one proposed. (author)

  6. Classification of Polar-Thermal Eigenfaces using Multilayer Perceptron for Human Face Recognition

    CERN Document Server

    Bhowmik, Mrinal Kanti; Nasipuri, Mita; Basu, Dipak Kumar; Kundu, Mahantapas

    2010-01-01

    This paper presents a novel approach to handle the challenges of face recognition. In this work thermal face images are considered, which minimizes the affect of illumination changes and occlusion due to moustache, beards, adornments etc. The proposed approach registers the training and testing thermal face images in polar coordinate, which is capable to handle complicacies introduced by scaling and rotation. Polar images are projected into eigenspace and finally classified using a multi-layer perceptron. In the experiments we have used Object Tracking and Classification Beyond Visible Spectrum (OTCBVS) database benchmark thermal face images. Experimental results show that the proposed approach significantly improves the verification and identification performance and the success rate is 97.05%.

  7. Identification of Determinants for Globalization of SMEs using Multi-Layer Perceptron Neural Networks

    Directory of Open Access Journals (Sweden)

    Umar Draz

    2016-01-01

    Full Text Available SMEs (Small and Medium Sized Enterprises sector is facing problems relating to implementation of international quality standards. These SMEs need to identify factors affecting business success abroad for intelligent allocation of resources to the process of internationalization. In this paper, MLP NN (Multi-Layer Perceptron Neural Network has been used for identifying relative importance of key variables related to firm basics, manufacturing, quality inspection labs and level of education in determining the exporting status of Pakistani SMEs. A survey has been conducted for scoring out the pertinent variables in SMEs and coded in MLP NNs. It is found that ?firm registered with OEM (Original Equipment Manufacturer and ?size of firm? are the most important in determining exporting status of SMEs followed by other variables. For internationalization, the results aid policy makers in formulating strategies

  8. Highly Accurate Multi-layer Perceptron Neural Network for Air Data System

    Directory of Open Access Journals (Sweden)

    H. S. Krishna

    2009-11-01

    Full Text Available The error backpropagation multi-layer perceptron algorithm is revisited. This algorithm is used to train and validate two models of three-layer neural networks that can be used to calibrate a 5-hole pressure probe. This paper addresses Occam's Razor problem as it describes the adhoc training methodology applied to improve accuracy and sensitivity. The trained outputs from 5-4-3 feed-forward network architecture with jump connection are comparable to second decimal digit (~0.05 accuracy, hitherto unreported in literature.Defence Science Journal, 2009,59(6, pp.670-674,DOI:http://dx.doi.org/10.14429/dsj.59.1574

  9. An Analog Multilayer Perceptron Neural Network for a Portable Electronic Nose

    Directory of Open Access Journals (Sweden)

    Chih-Heng Pan

    2012-12-01

    Full Text Available This study examines an analog circuit comprising a multilayer perceptron neural network (MLPNN. This study proposes a low-power and small-area analog MLP circuit to implement in an E-nose as a classifier, such that the E-nose would be relatively small, power-efficient, and portable. The analog MLP circuit had only four input neurons, four hidden neurons, and one output neuron. The circuit was designed and fabricated using a 0.18 μm standard CMOS process with a 1.8 V supply. The power consumption was 0.553 mW, and the area was approximately 1.36 × 1.36 mm2. The chip measurements showed that this MLPNN successfully identified the fruit odors of bananas, lemons, and lychees with 91.7% accuracy.

  10. A New Approach to Predicting Bankruptcy: Combining DEA and Multi-Layer Perceptron

    Directory of Open Access Journals (Sweden)

    Ayan Mukhopadhyay

    2012-07-01

    Full Text Available The question of financial health and sustenance of a firm is so intriguing that it has spanned numerous studies. For investors,stakeholders and lenders, assessing the risk associated with an enterprise is vital. Several tools have been formulated to deal with predicting the solvency of a firm. This paper attempts to combine Data Envelopment Analysis and Multi-Layer Perceptron (MLP to suggest a new method for prediction of bankruptcy that not only focusses on historical financial data of firms that filed for bankruptcy like other past studies but also takes into account the data of those firms that were likely to do so. This method thus identifies firms that have a high chance of facing bankruptcy along with those that have filed for bankruptcy. The performance of this procedure is compared with MLP. The suggested method outperforms MLP in prediction of bankruptcy.

  11. Exchange rate prediction with multilayer perceptron neural network using gold price as external factor

    Directory of Open Access Journals (Sweden)

    Mohammad Fathian

    2012-04-01

    Full Text Available In this paper, the problem of predicting the exchange rate time series in the foreign exchange rate market is going to be solved using a time-delayed multilayer perceptron neural network with gold price as external factor. The input for the learning phase of the artificial neural network are the exchange rate data of the last five days plus the gold price in two different currencies of the exchange rate as the external factor for helping the artificial neural network improving its forecast accuracy. The five-day delay has been chosen because of the weekly cyclic behavior of the exchange rate time series with the consideration of two holidays in a week. The result of forecasts are then compared with using the multilayer peceptron neural network without gold price external factor by two most important evaluation techniques in the literature of exchange rate prediction. For the experimental analysis phase, the data of three important exchange rates of EUR/USD, GBP/USD, and USD/JPY are used.

  12. Detection of Pathological and Normal Heartbeat Using Wavelet Packet, Support Vector Machines and Multilayer Perceptron

    Directory of Open Access Journals (Sweden)

    Alejandro J. Orozco-Naranjo

    2013-11-01

    Full Text Available This paper presents the results obtained by developing a methodology to detect 5 types of heartbeats (Normal (N, Right bundle branch block (RBBB, Left bundle branch block (LBBB, Premature atrial contraction (APC and Premature ventricular contraction (PVC, using Wavelet transform packets with non-adaptative mode applied on features extraction from heartbeats. It was used the Shannon function to calculate the entropy and It was added an identification nodes stage per every type of cardiac signal in the Wavelet tree. The using of Wavelet packets transform allows the access to information which results of decomposition of low and high frecuency, giving providing a more integral analysis than achieved by the discrete Wavelet transform. Three families of mother Wavelet were evaluated on transformation: Daubechies, Symlet and Reverse Biorthogonal, which were results from a previous research in that were identified the mother Wavelet that had higher entropy with the cardiac signals. With non-adaptive mode, the computational cost is reduced when Wavelet packets are used; this cost represents the most marked disadvantage from the transform. To classify the heartbeats were used Support Vector Machines and Multilayer Perceptron. The best classification error was achieved employing Support Vector Machine and a radial basis function; it was 2.57 %.

  13. Photometric redshifts with the Multilayer Perceptron Neural Network: application to the HDF-S and SDSS

    CERN Document Server

    Vanzella, E; Fontana, A; Nonino, M; Arnouts, S; Giallongo, E; Grazian, A; Fasano, G; Popesso, P; Saracco, P; Zaggia, S R

    2003-01-01

    We present a technique for the estimation of photometric redshifts based on feed-forward neural networks. The Multilayer Perceptron (MLP) Artificial Neural Network is used to predict photometric redshifts in the HDF-S from an ultra deep multicolor catalog. Various possible approaches for the training of the neural network are explored, including the deepest and most complete spectroscopic redshift catalog currently available (the Hubble Deep Field North dataset) and models of the spectral energy distribution of galaxies available in the literature. The MLP can be trained on observed data, theoretical data and mixed samples. The prediction of the method is tested on the spectroscopic sample in the HDF-S (44 galaxies). Over the entire redshift range, $0.1

  14. Geomagnetic Dst index forecast using a multilayer perceptrons artificial neural network

    International Nuclear Information System (INIS)

    Complete text of publication follows. The best known manifestations of the impact of solar wind on the magnetosphere are the geomagnetic storms. The prediction of geomagnetic field behavior allows the alert of geomagnetic storms occurrence, as those phenomena can cause many damages in the planet. The Artificial Intelligence tools have been applied in many multidisciplinary studies, covering several areas of knowledge, as a choice of approach to the solution of problems with characteristics like non-linearity, imprecision, and other features that can not be easily solved with conventional computational models. Techniques such as Artificial Neural Networks, Expert Systems and Decision Trees have been used in the Space Weather studies to perform tasks such as forecasting geomagnetic storms and the investigation of rules and parameters related on its occurrence. The main focus of this work is on forecasting the geomagnetic field behavior, represented this time by the Dst index, using for that task, mainly, the interplanetary magnetic field components and solar wind data. The tool chosen here to solve the non-linear problem was a Multi-layer Perceptrons Artificial Neural Network, trained with the backpropagation algorithm. Unlike what was done in other studies, we chose to predict calm and disturbed periods like, for example, a full month of data, for application in a real time forecasting system. It was possible to predict the geomagnetic Dst index one or two hours before with great percentage efficiency.

  15. Wideband dynamic behavioral modeling of reflective semiconductor optical amplifiers using a tapped-delay multilayer perceptron.

    Science.gov (United States)

    Liu, Zhansheng; Violas, Manuel Alberto; Carvalho, Nuno Borges

    2013-02-11

    In this paper, we propose a wideband dynamic behavioral model for a bulk reflective semiconductor optical amplifier (RSOA) used as a modulator in colorless radio over fiber (RoF) systems using a tapped-delay multilayer perceptron (TDMLP). 64 quadrature amplitude modulation (QAM) signals with 20 Msymbol/s were used to train, validate and test the model. Nonlinear distortion and dynamic effects induced by the RSOA modulator are demonstrated. The parameters of the model such as the number of nodes in the hidden layer and memory depth were optimized to ensure the generality and accuracy. The normalized mean square error (NMSE) is used as a figure of merit. The NMSE was up to -44.33 dB when the number of nodes in the hidden layer and memory depth were set to 20 and 3, respectively. The TDMLP model can accurately approximate to the dynamic characteristics of the RSOA modulator. The dynamic AM-AM and dynamic AM-PM distortions of the RSOA modulator are drawn. The results show that the single hidden layer TDMLP can provide accurate approximation for behaviors of the RSOA modulator. PMID:23481795

  16. Multilayer perceptron neural network for downscaling rainfall in arid region: A case study of Baluchistan, Pakistan

    Indian Academy of Sciences (India)

    Kamal Ahmed; Shamsuddin Shahid; Sobri Bin Haroon; Wang Xiao-Jun

    2015-08-01

    Downscaling rainfall in an arid region is much challenging compared to wet region due to erratic and infrequent behaviour of rainfall in the arid region. The complexity is further aggregated due to scarcity of data in such regions. A multilayer perceptron (MLP) neural network has been proposed in the present study for the downscaling of rainfall in the data scarce arid region of Baluchistan province of Pakistan, which is considered as one of the most vulnerable areas of Pakistan to climate change. The National Center for Environmental Prediction (NCEP) reanalysis datasets from 20 grid points surrounding the study area were used to select the predictors using principal component analysis. Monthly rainfall data for the time periods 1961–1990 and 1991–2001 were used for the calibration and validation of the MLP model, respectively. The performance of the model was assessed using various statistics including mean, variance, quartiles, root mean square error (RMSE), mean bias error (MBE), coefficient of determination (R2) and Nash–Sutcliffe efficiency (NSE). Comparisons of mean monthly time series of observed and downscaled rainfall showed good agreement during both calibration and validation periods, while the downscaling model was found to underpredict rainfall variance in both periods. Other statistical parameters also revealed good agreement between observed and downscaled rainfall during both calibration and validation periods in most of the stations.

  17. Face Recognition through Multilayer Perceptron (MLP and Learning Vector Quantization (LVQ

    Directory of Open Access Journals (Sweden)

    Dr. Ikvinderpal Singh

    2012-12-01

    Full Text Available Face recognition is challenging problems and there is still a lot of work that needs to be done in this area. Over the past ten years, face recognition has received substantial attention from researchers in biometrics, pattern recognition, computer vision, and cognitive psychology communities. This common interest in facial recognition technology among researchers working in diverse fields is motivated both by the remarkable ability to recognize people and by the increased attention being devoted to security applications. Applications of face recognition can be found in security, tracking, multimedia, and entertainment domains.This paper presents a face recognition system using artificial neural network. Here, we have designed a neural network with some own set network parameters. The results presented here have been obtained using two basic methods: multilayer perceptron (MLP, and learning vector quantization (LVQ. In both cases, two kinds of data have been fed to the classifiers: reduced resolution images (gray level or segmented, and feature vectors. The experimental results also show that, for the approaches considered here, analyzing gray level images produced better results than analyzing geometrical features, either because of the errors introduced during their extraction or because the original images have a richer information content. Furthermore, training times were much shorter for LVQ than for MLP. On the other hand, MLP achieved lower error rates when dealing with geometrical features.

  18. Using multilayer perceptron and a satellite image for the estimation of soil salinity

    International Nuclear Information System (INIS)

    Applying the model of the Perceptron multilayer with momentum of an artificial neural network particularly and a multispectral image of high resolution spatial and radiometric, for the first time estimated the salinity of the soil cultivated with sugar cane. The study area is the UBPC 'Lazaro Romero' of the sugar company 'Hector Molina' of the locality San Nicolas de Bari, Havana province, located at 22° 44' North latitude and 81 ° 56' longitude West. The experiments were made in the framework of the El-479 project funded by the Inter universities Council of Flanders, Belgium. 36 samples geo referenced of soils were taken at 3 depths in each of the 4 sugar cane selected blocks, which determined the electrical conductivity of the saturation extract; half of that amount of data was used for the training of the network and the other half for control in a computer program of the artificial neural network created to that effect, together with the reflectance of vegetation indexes for the image, which were maps of electrical conductivity of each block and bands. They were compared with those obtained by simple linear regression between the normalized difference vegetation index and electrical conductivity, Ndv with the approach of the neuronal network, the correlation coefficient was 0.78 to 0.83, while the linear regression was between 0.65 to 0.75

  19. Multilayer perceptron neural network for downscaling rainfall in arid region: A case study of Baluchistan, Pakistan

    Science.gov (United States)

    Ahmed, Kamal; Shahid, Shamsuddin; Haroon, Sobri Bin; Xiao-jun, Wang

    2015-08-01

    Downscaling rainfall in an arid region is much challenging compared to wet region due to erratic and infrequent behaviour of rainfall in the arid region. The complexity is further aggregated due to scarcity of data in such regions. A multilayer perceptron (MLP) neural network has been proposed in the present study for the downscaling of rainfall in the data scarce arid region of Baluchistan province of Pakistan, which is considered as one of the most vulnerable areas of Pakistan to climate change. The National Center for Environmental Prediction (NCEP) reanalysis datasets from 20 grid points surrounding the study area were used to select the predictors using principal component analysis. Monthly rainfall data for the time periods 1961-1990 and 1991-2001 were used for the calibration and validation of the MLP model, respectively. The performance of the model was assessed using various statistics including mean, variance, quartiles, root mean square error (RMSE), mean bias error (MBE), coefficient of determination (R 2) and Nash-Sutcliffe efficiency (NSE). Comparisons of mean monthly time series of observed and downscaled rainfall showed good agreement during both calibration and validation periods, while the downscaling model was found to underpredict rainfall variance in both periods. Other statistical parameters also revealed good agreement between observed and downscaled rainfall during both calibration and validation periods in most of the stations.

  20. An application of the multilayer perceptron: Solar radiation maps in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Hontoria, L.; Aguilera, J. [Grupo Investigacion y Desarrollo en Energia Solar y Automatica, Dpto. de Ingenieria Electronica, de Telecomunicaciones y Automatica, Escuela Politecnica Superior de Jaen, Campus de las Lagunillas, Universidad de Jaen, 23071 Jaen (Spain); Zufiria, P. [Grupo de Redes Neuronales, Dpto. de Matematica Aplicada a las Tecnologias de la Informacion, ETSI Telecomunicaciones, UPM Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2005-11-01

    In this work an application of a methodology to obtain solar radiation maps is presented. This methodology is based on a neural network system [Lippmann, R.P., 1987. An introduction to computing with neural nets. IEEE ASSP Magazine, 4-22] called Multi-Layer Perceptron (MLP) [Haykin, S., 1994. Neural Networks. A Comprehensive Foundation. Macmillan Publishing Company; Hornik, K., Stinchcombe, M., White, H., 1989. Multilayer feedforward networks are universal approximators. Neural Networks, 2(5), 359-366]. To obtain a solar radiation map it is necessary to know the solar radiation of many points spread wide across the zone of the map where it is going to be drawn. For most of the locations all over the world the records of these data (solar radiation in whatever scale, daily or hourly values) are non-existent. Only very few locations have the privilege of having good meteorological stations where records of solar radiation have being registered. But even in those locations with historical records of solar data, the quality of these solar series is not as good as it should be for most purposes. In addition, to draw solar radiation maps the number of points on the maps (real sites) that it is necessary to work with makes this problem difficult to solve. Nevertheless, with the application of the methodology proposed in this paper, this problem has been solved and solar radiation maps have been obtained for a small region of Spain: Jaen province, a southern province of Spain between parallels 38{sup o}25' N and 37{sup o}25' N, and meridians 4{sup o}10' W and 2{sup o}10' W, and for a larger region: Andalucia, the most southern region of Spain situated between parallels 38{sup o}40' N and 36{sup o}00' N, and meridians 7{sup o}30' W and 1{sup o}40' W. (author)

  1. Recurrent network of perceptrons with three state synapses achieves competitive classification on real inputs

    Science.gov (United States)

    Amit, Yali; Walker, Jacob

    2012-01-01

    We describe an attractor network of binary perceptrons receiving inputs from a retinotopic visual feature layer. Each class is represented by a random subpopulation of the attractor layer, which is turned on in a supervised manner during learning of the feed forward connections. These are discrete three state synapses and are updated based on a simple field dependent Hebbian rule. For testing, the attractor layer is initialized by the feedforward inputs and then undergoes asynchronous random updating until convergence to a stable state. Classification is indicated by the sub-population that is persistently activated. The contribution of this paper is two-fold. This is the first example of competitive classification rates of real data being achieved through recurrent dynamics in the attractor layer, which is only stable if recurrent inhibition is introduced. Second, we demonstrate that employing three state synapses with feedforward inhibition is essential for achieving the competitive classification rates due to the ability to effectively employ both positive and negative informative features. PMID:22737121

  2. Multilayer Perceptron Model for Nowcasting Visibility from Surface Observations: Results and Sensitivity to Dissimilar Station Altitudes

    Science.gov (United States)

    Chaudhuri, Sutapa; Das, Debanjana; Sarkar, Ishita; Goswami, Sayantika

    2015-10-01

    The reduction in the visibility during fog significantly influences surface as well as air transport operations. The prediction of fog remains difficult despite improvements in numerical weather prediction models. The present study aims at identifying a suitable neural network model with proper architecture to provide precise nowcast of the horizontal visibility during fog over the airports of three significantly affected metropolises of India, namely: Kolkata (22°32'N; 88°20'E), Delhi (28°38'N; 77°12'E) and Bengaluru (12°95'N; 77°72'E). The investigation shows that the multilayer perceptron (MLP) model provides considerably less error in nowcasting the visibility during fog over the said metropolises than radial basis function network, generalized regression neural network or linear neural network. The MLP models of different architectures are trained with the data and records from 2000 to 2010. The model results are validated with observations from 2011 to 2014. Our results reveal that MLP models with different configurations (1) four input layers, three hidden layers with three hidden nodes in each layer and a single output; (2) four input layers with two hidden layers having one hidden node in the first hidden layer and two hidden nodes in the second hidden layer, and a single output layer; and (3) four input layers with two hidden layers having two hidden nodes in each hidden layer and a single output layer] provide minimum error in nowcasting the visibility during fog over the airports of Kolkata, Delhi and Bengaluru, respectively. The results show that the MLP model is well suited for nowcasting visibility during fog with 6 h lead time, however, the study reveals that the MLP model sensitive to dissimilar station altitudes in nowcasting visibility, as the minimum prediction error for the three metropolises having dissimilar mean sea level altitudes is observed through different configurations of the model.

  3. Cross Validation Evaluation for Breast Cancer Prediction Using Multilayer Perceptron Neural Networks

    Directory of Open Access Journals (Sweden)

    Shirin A. Mojarad

    2011-01-01

    Full Text Available Problem statement: The presence of metastasis in the regional lymph nodes is the most important factor in predicting prognosis in breast cancer. Many biomarkers have been identified that appear to relate to the aggressive behaviour of cancer. However, the nonlinear relation of these markers to nodal status and also the existence of complex interaction between markers have prohibited an accurate prognosis. Approach: The aim of this study is to investigate the effectiveness of a Multilayer Perceptron (MLP for predicting breast cancer progression using a set of four biomarkers of breast tumors. The biomarkers include DNA ploidy, cell cycle distribution (G0G1/G2M, steroid receptors (ER/PR and S-Phase Fraction (SPF. A further objective of the study is to explore the predictive potential of these markers in defining the state of nodal involvement in breast cancer. Two methods of outcome evaluation viz. stratified and simple k-fold Cross Validation (CV are studied in order to assess their accuracy and reliability for neural network validation. Criteria such as output accuracy, sensitivity and specificity are used for selecting the best validation technique besides evaluating the network outcome for different combinations of markers. Results: The results show that stratified 2-fold CV is more accurate and reliable compared to simple k-fold CV as it obtains a higher accuracy and specificity and also provides a more stable network validation in terms of sensitivity. Best prediction results are obtained by using an individual marker-SPF which obtains an accuracy of 65%. Conclusion/Recommendations: Our findings suggest that MLP-based analysis provides an accurate and reliable platform for breast cancer prediction given that an appropriate design and validation method is employed.

  4. Group Session Key Exchange Multilayer Perceptron Based Simulated Annealing Guided Automata and Comparison Based Metamorphosed Encryption in Wireless Communication (GSMLPSA

    Directory of Open Access Journals (Sweden)

    Arindam Sarkar

    2013-08-01

    Full Text Available In this paper, a group session Key Exchange multilayer Perceptron based Simulated Annealing guidedAutomata and Comparison based Metamorphosed encryption technique (GSMLPSA has been proposed inwireless communication of data/information. Both sender and receiver uses identical multilayer perceptronand depending on the final output of the both side multilayer perceptron, weights vector of hidden layer gettuned in both ends. As a results both perceptrons generates identical weight vectors which is consider as anone time session key. In GSMLPSA technique plain text is encrypted using metamorphosed code table forproducing level 1 encrypted text. Then comparison based technique is used to further encerypt the level 1encrypted text and produce level 2 encrypted text. Simulated Annealing based keystream is xored with theleve2 encrypted text and form a level 3 encrypted text. Finally level 3 encrypted text is xored with the MLPbased session key and get transmitted to the receiver. GSMLPSA technique uses two keys for encryptionpurpose. SA based key get further encrypted using Automata based technique and finally xored with MLPbased session key and transmitted to the receiver. This technique ensures that if intruders intercept the keyof the keystream then also values of the key not be known to the intruders because of the automata basedencoding. Receiver will perform same operation in reverse order to get the plain text back. Two partiescan swap over a common key using synchronization between their own multilayer perceptrons. But theproblem crop up when group of N parties desire to swap over a key. Since in this case each communicatingparty has to synchronize with other for swapping over the key. So, if there are N parties then total numberof synchronizations needed before swapping over the actual key is O(N2. GSMLPSA scheme offers a noveltechnique in which complete binary tree structure is follows for key swapping over. Using proposedalgorithm a set of N parties can be able to share a common key with only O(log2 N synchronization.Parametric tests have been done and results are compared with some existing classical techniques, whichshow comparable results for the proposed technique

  5. APPLICATION OF A MULTI-LAYER PERCEPTRON NETWORK FOR DETECTION OF HUMAN FACES ON A LARGE DATABASE

    OpenAIRE

    Salihmuhsin, Metin; İşler, Yavuz Selim

    2015-01-01

    In this paper, we present a face detection system that we have developed. The system is consisted of a camera, a computer, an image acquisition setup and a face detection method written in Matlab.  In order to test detection capability of the system, we have collected a database that contains 125 different images of 125 different people with this system. A program based on a multilayer perceptron network (MLP) is developed in order to detect faces. The program works in two levels and uses the...

  6. Fast accurate MEG source localization using a multilayer perceptron trained with real brain noise

    International Nuclear Information System (INIS)

    Iterative gradient methods such as Levenberg-Marquardt (LM) are in widespread use for source localization from electroencephalographic (EEG) and magnetoencephalographic (MEG) signals. Unfortunately, LM depends sensitively on the initial guess, necessitating repeated runs. This, combined with LM's high per-step cost, makes its computational burden quite high. To reduce this burden, we trained a multilayer perceptron (MLP) as a real-time localizer. We used an analytical model of quasistatic electromagnetic propagation through a spherical head to map randomly chosen dipoles to sensor activities according to the sensor geometry of a 4D Neuroimaging Neuromag-122 MEG system, and trained a MLP to invert this mapping in the absence of noise or in the presence of various sorts of noise such as white Gaussian noise, correlated noise, or real brain noise. A MLP structure was chosen to trade off computation and accuracy. This MLP was trained four times, with each type of noise. We measured the effects of initial guesses on LM performance, which motivated a hybrid MLP-start-LM method, in which the trained MLP initializes LM. We also compared the localization performance of LM, MLPs, and hybrid MLP-start-LMs for realistic brain signals. Trained MLPs are much faster than other methods, while the hybrid MLP-start-LMs are faster and more accurate than fixed-4-start-LM. In particular, the hybrid MLP-start-LM initialized by a MLP trained with the real brain noise dataset is 60 times faster and is comparable in accuracy to random-20-start-LM, and this hybrid system (localization error: 0.28 cm, computation time: 36 ms) shows almost as good performance as optimal-1-start-LM (localization error: 0.23 cm, computation time: 22 ms), which initializes LM with the correct dipole location. MLPs trained with noise perform better than the MLP trained without noise, and the MLP trained with real brain noise is almost as good an initial guesser for LM as the correct dipole location. (author) )

  7. Multilayer Perceptron Neural Networks Model for Meteosat Second Generation SEVIRI Daytime Cloud Masking

    DEFF Research Database (Denmark)

    Proud, Simon Richard

    2015-01-01

    sigmoid layer, trained with the error back-propagation algorithm. The model is fed by six bands of MSG data (0.6, 0.8, 1.6, 3.9, 6.2 and 10.8 μm) with 10 hidden nodes. The multiple-layer perceptrons lead to a cloud detection accuracy of 88.96%, when trained to map two predefined values that classify cloud...

  8. The effect of imposing 'fractional abundance constraints' onto the multilayer perceptron for sub-pixel land cover classification

    Science.gov (United States)

    Heremans, Stien; Suykens, Johan A. K.; Van Orshoven, Jos

    2016-02-01

    To be physically interpretable, sub-pixel land cover fractions or abundances should fulfill two constraints, the Abundance Non-negativity Constraint (ANC) and the Abundance Sum-to-one Constraint (ASC). This paper focuses on the effect of imposing these constraints onto the MultiLayer Perceptron (MLP) for a multi-class sub-pixel land cover classification of a time series of low resolution MODIS-images covering the northern part of Belgium. Two constraining modes were compared, (i) an in-training approach that uses 'softmax' as the transfer function in the MLP's output layer and (ii) a post-training approach that linearly rescales the outputs of the unconstrained MLP. Our results demonstrate that the pixel-level prediction accuracy is markedly increased by the explicit enforcement, both in-training and post-training, of the ANC and the ASC. For aggregations of pixels (municipalities), the constrained perceptrons perform at least as well as their unconstrained counterparts. Although the difference in performance between the in-training and post-training approach is small, we recommend the former for integrating the fractional abundance constraints into MLPs meant for sub-pixel land cover estimation, regardless of the targeted level of spatial aggregation.

  9. Exploiting Heavy Tails in Training Times of Multilayer Perceptrons. A Case Study with the UCI Thyroid Disease Database

    CERN Document Server

    Cebrian, Manuel

    2007-01-01

    The random initialization of weights of a multilayer perceptron makes it possible to model its training process as a Las Vegas algorithm, i.e. a randomized algorithm which stops when some required training error is obtained, and whose execution time is a random variable. This modelling is used to perform a case study on a well-known pattern recognition benchmark: the UCI Thyroid Disease Database. Empirical evidence is presented of the training time probability distribution exhibiting a heavy tail behavior, meaning a big probability mass of long executions. This fact is exploited to reduce the training time cost by applying two simple restart strategies. The first assumes full knowledge of the distribution yielding a 40% cut down in expected time with respect to the training without restarts. The second, assumes null knowledge, yielding a reduction ranging from 9% to 23%.

  10. Improving the Multilayer Perceptron Learning by Using a Method to Calculate the Initial Weights with the Similarity Quality Measure Based on Fuzzy Sets and Particle Swarms

    Directory of Open Access Journals (Sweden)

    Lenniet Coello

    2015-01-01

    Full Text Available The most widely used neural network model is Multilayer Perceptron (MLP, in which training of the connection weights is normally completed by a Back Propagation learning algorithm. G ood initial values of weights bear a fast convergence and a better generalization capability even with simple gradient - based error minimization techniques. This work presen ts a method to calculate the initial weights in order to train the Multilayer Perceptron Model. The method named PSO+RST+FUZZY is based on the similarity quality measure proposed within the framework of the extended Rough Set Theory that employs fuzzy sets to characterize the domain of similarity thresholds. Sensitivity of BP to initial weights with PSO+RST+FUZZY was studied experimentally, showing better performance than other methods used to calculate feature weights .

  11. Lithofacies prediction from well log data using a multilayer perceptron (MLP) and Kohonen's self-organizing map (SOM) - a case study from the Algerian Sahara

    Science.gov (United States)

    Ouadfeul, S.-A.; Aliouane, L.

    2013-06-01

    In this paper, a combination of supervised and unsupervised leanings is used for lithofacies classification from well log data. The main idea consists of enhancing the multilayer perceptron (MLP) learning by the output of the self-organizing map (SOM) neural network. Application to real data of two wells located the Algerian Sahara clearly shows that the lithofacies model built by the neural combination is able to give better results than a self-organizing map.

  12. Critical heat flux prediction by using radial basis function and multilayer perceptron neural networks: A comparison study

    Energy Technology Data Exchange (ETDEWEB)

    Vaziri, Nima [Department of Physics, Islamic Azad University, Karaj Branch, Moazen Blvd., Rajaee shahr (Iran, Islamic Republic of)]. E-mail: n.vaziri@gmail.com; Hojabri, Alireza [Department of Physics, Islamic Azad University, Karaj Branch, Moazen Blvd., Rajaee shahr (Iran, Islamic Republic of); Erfani, Ali [Department of Physics, Islamic Azad University, Karaj Branch, Moazen Blvd., Rajaee shahr (Iran, Islamic Republic of); Monsefi, Mehrdad [Department of Physics, Islamic Azad University, Karaj Branch, Moazen Blvd., Rajaee shahr (Iran, Islamic Republic of); Nilforooshan, Behnam [Department of Physics, Islamic Azad University, Karaj Branch, Moazen Blvd., Rajaee shahr (Iran, Islamic Republic of)

    2007-02-15

    Critical heat flux (CHF) is an important parameter for the design of nuclear reactors. Although many experimental and theoretical researches have been performed, there is not a single correlation to predict CHF because it is influenced by many parameters. These parameters are based on fixed inlet, local and fixed outlet conditions. Artificial neural networks (ANNs) have been applied to a wide variety of different areas such as prediction, approximation, modeling and classification. In this study, two types of neural networks, radial basis function (RBF) and multilayer perceptron (MLP), are trained with the experimental CHF data and their performances are compared. RBF predicts CHF with root mean square (RMS) errors of 0.24%, 7.9%, 0.16% and MLP predicts CHF with RMS errors of 1.29%, 8.31% and 2.71%, in fixed inlet conditions, local conditions and fixed outlet conditions, respectively. The results show that neural networks with RBF structure have superior performance in CHF data prediction over MLP neural networks. The parametric trends of CHF obtained by the trained ANNs are also evaluated and results reported.

  13. Multilayer perceptron applied to the estimation of the influence of the solar spectral distribution on thin-film photovoltaic modules

    International Nuclear Information System (INIS)

    Highlights: Multilayer perceptrons are used to simulate the IV curve of thin-film PV modules. APE from the spectral irradiance was added as an input variable to the network. A self-organised map is used to select the curves used for training the network. Curve error and maximum power error decrease when using this technique. This method could provide accurate estimation of the output of a PV plant. - Abstract: In this paper, we propose the use of a methodology to characterise the electrical parameters of several thin-film photovoltaic module technologies. This methodology allows us to use not only solar irradiance and module temperature as classical models do, but also spectral distribution of solar radiation. The methodology is based on the use of neural network models. From all measured IV curves of a module, a previous selection of them has been used in order to train the neural network model. This selection is performed using a Kohonen self-organising map fed with spectral data. This spectral information has been added as an input to the neural network itself. The results show that the incorporation of spectral measurements to simulate thin-film modules improves significantly both the fitting of the predicted IV curve to the measured one and the peak power point estimation

  14. Time series modeling with pruned multi-layer perceptron and 2-stage damped least-squares method

    International Nuclear Information System (INIS)

    A Multi-Layer Perceptron (MLP) defines a family of artificial neural networks often used in TS modeling and forecasting. Because of its ''black box'' aspect, many researchers refuse to use it. Moreover, the optimization (often based on the exhaustive approach where ''all'' configurations are tested) and learning phases of this artificial intelligence tool (often based on the Levenberg-Marquardt algorithm; LMA) are weaknesses of this approach (exhaustively and local minima). These two tasks must be repeated depending on the knowledge of each new problem studied, making the process, long, laborious and not systematically robust. In this paper a pruning process is proposed. This method allows, during the training phase, to carry out an inputs selecting method activating (or not) inter-nodes connections in order to verify if forecasting is improved. We propose to use iteratively the popular damped least-squares method to activate inputs and neurons. A first pass is applied to 10% of the learning sample to determine weights significantly different from 0 and delete other. Then a classical batch process based on LMA is used with the new MLP. The validation is done using 25 measured meteorological TS and cross-comparing the prediction results of the classical LMA and the 2-stage LMA

  15. Adaptive Weibull Multiplicative Model and Multilayer Perceptron Neural Networks for Dark-Spot Detection from SAR Imagery

    Directory of Open Access Journals (Sweden)

    Alireza Taravat

    2014-12-01

    Full Text Available Oil spills represent a major threat to ocean ecosystems and their environmental status. Previous studies have shown that Synthetic Aperture Radar (SAR, as its recording is independent of clouds and weather, can be effectively used for the detection and classification of oil spills. Dark formation detection is the first and critical stage in oil-spill detection procedures. In this paper, a novel approach for automated dark-spot detection in SAR imagery is presented. A new approach from the combination of adaptive Weibull Multiplicative Model (WMM and MultiLayer Perceptron (MLP neural networks is proposed to differentiate between dark spots and the background. The results have been compared with the results of a model combining non-adaptive WMM and pulse coupled neural networks. The presented approach overcomes the non-adaptive WMM filter setting parameters by developing an adaptive WMM model which is a step ahead towards a full automatic dark spot detection. The proposed approach was tested on 60 ENVISAT and ERS2 images which contained dark spots. For the overall dataset, an average accuracy of 94.65% was obtained. Our experimental results demonstrate that the proposed approach is very robust and effective where the non-adaptive WMM & pulse coupled neural network (PCNN model generates poor accuracies.

  16. Utility of coactive neuro-fuzzy inference system for pan evaporation modeling in comparison with multilayer perceptron

    Science.gov (United States)

    Tabari, Hossein; Hosseinzadeh Talaee, P.; Abghari, Hirad

    2012-05-01

    Estimation of pan evaporation ( E pan) using black-box models has received a great deal of attention in developing countries where measurements of E pan are spatially and temporally limited. Multilayer perceptron (MLP) and coactive neuro-fuzzy inference system (CANFIS) models were used to predict daily E pan for a semi-arid region of Iran. Six MLP and CANFIS models comprising various combinations of daily meteorological parameters were developed. The performances of the models were tested using correlation coefficient ( r), root mean square error (RMSE), mean absolute error (MAE) and percentage error of estimate (PE). It was found that the MLP6 model with the Momentum learning algorithm and the Tanh activation function, which requires all input parameters, presented the most accurate E pan predictions ( r = 0.97, RMSE = 0.81 mm day-1, MAE = 0.63 mm day-1 and PE = 0.58 %). The results also showed that the most accurate E pan predictions with a CANFIS model can be achieved with the Takagi-Sugeno-Kang (TSK) fuzzy model and the Gaussian membership function. Overall performances revealed that the MLP method was better suited than CANFIS method for modeling the E pan process.

  17. Critical heat flux prediction by using radial basis function and multilayer perceptron neural networks: A comparison study

    International Nuclear Information System (INIS)

    Critical heat flux (CHF) is an important parameter for the design of nuclear reactors. Although many experimental and theoretical researches have been performed, there is not a single correlation to predict CHF because it is influenced by many parameters. These parameters are based on fixed inlet, local and fixed outlet conditions. Artificial neural networks (ANNs) have been applied to a wide variety of different areas such as prediction, approximation, modeling and classification. In this study, two types of neural networks, radial basis function (RBF) and multilayer perceptron (MLP), are trained with the experimental CHF data and their performances are compared. RBF predicts CHF with root mean square (RMS) errors of 0.24%, 7.9%, 0.16% and MLP predicts CHF with RMS errors of 1.29%, 8.31% and 2.71%, in fixed inlet conditions, local conditions and fixed outlet conditions, respectively. The results show that neural networks with RBF structure have superior performance in CHF data prediction over MLP neural networks. The parametric trends of CHF obtained by the trained ANNs are also evaluated and results reported

  18. Application of Multi-Layered Perceptron Neural network (MLPNN to Combined Economic and Emission Dispatch

    Directory of Open Access Journals (Sweden)

    Sarakhs branch

    2012-01-01

    Full Text Available This paper presents a multi-layered perceptronneural network (MLPNN method to solve the combinedeconomic and emission dispatch (CEED problem. The harmfulecological effects caused by the emission of particulate andgaseous pollutants like sulfur dioxide (SO2 and oxides ofnitrogen ( NOx can be reduced by adequate distribution ofload between the plants of a power system. However, this leadsto a noticeable increase in the operating cost of the plants. Thispaper presents the (MLPNN method applied for the successfuloperation of the power system subject to economical andenvironmental constraints. The proposed MLP NN method istested for a three plant thermal power system and the results arecompared with the solutions obtained from the classical lambdaiterative technique and simple genetic algorithm (SGA refinedgenetic algorithm (RGA method.

  19. Laser spot detection-based computer interface system using autoassociative multilayer perceptron with input-to-output mapping-sensitive error back propagation learning algorithm

    Science.gov (United States)

    Jeong, Sungmoon; Jung, Chanwoong; Kim, Cheol-Su; Shim, Jae Hoon; Lee, Minho

    2011-08-01

    This paper presents a new computer interface system based on laser spot detection and moving pattern analysis of the detected laser spots in real-time processing. We propose a systematic method that uses either the frame difference of successive input images or an autoassociative multilayer perceptron (AAMLP) to detect laser spots. The AAMLP is applied only to areas of the input images where the frame difference of the successive images is not effective for detecting laser spots. In order to enhance the detection performance, the AAMLP is trained by a new training algorithm that increases the sensitivity of the input-to-output mapping of the AAMLP allowing a small variation in the input feature of the laser spot image to be successfully indicated. The proposed interface system is also able to keep track of the laser spot and recognize gesture commands. The moving pattern of the laser spot is recognized by using a multilayer perception. It is experimentally shown that the proposed computer interface system is fast enough for real-time operation with reliable accuracy.

  20. Modeling of gamma ray energy-absorption buildup factors for thermoluminescent dosimetric materials using multilayer perceptron neural network: A comparative study

    International Nuclear Information System (INIS)

    In this work, multilayered perceptron neural networks (MLPNNs) were presented for the computation of the gamma-ray energy absorption buildup factors (BA) of seven thermoluminescent dosimetric (TLD) materials [LiF, BeO, Na2B4O7, CaSO4, Li2B4O7, KMgF3, Ca3(PO4)2] in the energy region 0.015–15 MeV, and for penetration depths up to 10 mfp (mean-free-path). The MLPNNs have been trained by a Levenberg–Marquardt learning algorithm. The developed model is in 99% agreement with the ANSI/ANS-6.4.3 standard data set. Furthermore, the model is fast and does not require tremendous computational efforts. The estimated BA data for TLD materials have been given with penetration depth and incident photon energy as comparative to the results of the interpolation method using the Geometrical Progression (G-P) fitting formula. - Highlights: ► Gamma-ray energy absorption buildup factors estimation in TLD materials. ► The ANN approach can be alternative to G-P fitting method for BA calculations. ► The applied model is not time-consuming and easily predicted

  1. Determination of near-surface structures from multi-channel surface wave data using multi-layer perceptron neural network (MLPNN) algorithm

    Science.gov (United States)

    aylak, a?r?; Kaftan, ?lknur

    2014-12-01

    This study proposes the use of multi-layer perceptron neural networks (MLPNN) to invert dispersion curves obtained via multi-channel analysis of surface waves (MASW) for shear S-wave velocity profile. The dispersion curve used in inversion includes the fundamental-mode dispersion data. In order to investigate the applicability and performance of the proposed MLPNN algorithm, test studies were performed using both synthetic and field examples. Gaussian random noise with a standard deviation of 4 and 8% was added to the noise-free test data to make the synthetic test more realistic. The model parameters, such as S-wave velocities and thicknesses of the synthetic layered-earth model, were obtained for different S/N ratios and noise-free data. The field survey was performed over the natural gas pipeline, located in the Germencik district of Ayd?n city, western Turkey. The results show that depth, velocity, and location of the embedded natural gas pipe are successfully estimated with reasonably good approximation.

  2. Funciones de transferencia en el perceptrn multicapa: efecto de su combinacin en entrenamiento local y distribuido / Transfer functions in the multilayer perceptron: effects of its combination on local and distributed training

    Scientific Electronic Library Online (English)

    Yuleidys, Mejas Csar; Ramn, Carrasco Velar; Isbel, Ochoa Izquierdo; Edel, Moreno Lemus.

    2013-12-01

    Full Text Available El perceptrn multicapa (PMC) figura dentro de los tipos de redes neuronales artificiales (RNA) con resultados tiles en los estudios de relacin estructura-actividad. Dado que los volmenes de datos en proyectos de Bioinformtica son eventualmente grandes, se propuso evaluar algoritmos para acortar [...] el tiempo de entrenamiento de la red sin afectar su eficiencia. Se desarroll un algoritmo para el entrenamiento local y distribuido del PMC con la posibilidad de variar las funciones de transferencias para lo cual se utilizaron el Weka y la Plataforma de Tareas Distribuidas Tarenal para distribuir el entrenamiento del perceptrn multicapa. Se demostr que en dependencia de la muestra de entrenamiento, la variacin de las funciones de transferencia pueden reportar resultados mucho ms eficientes que los obtenidos con la clsica funcin Sigmoidal, con incremento de la g-media entre el 4.5 y el 17 %. Se encontr adems que en los entrenamientos distribuidos es posible alcanzar eventualmente mejores resultados que los logrados en ambiente local. Abstract in english The multilayer perceptron (PMC) ranks among the types of artificial neural networks (ANN), which has provided better results in studies of structure-activity relationship. As the data volumes in Bioinformatics' projects are eventually big, it was proposed to evaluate algorithms to shorten the traini [...] ng time of the network without affecting its efficiency. There were evaluated different tools that work with ANN and were selected Weka algorithm for extracting the network and the Platform for Distributed Task Tarenal to distribute the training of multilayer perceptron. Finally, it was developed a training algorithm for local and distributed the MLP with the possibility of varying transfer functions. It was shown that depending on the training sample, the change of transfer functions can yield results much more efficient than those obtained with the classic sigmoid function with increased g-media between 4.5 and 17 %. Moreover, it was found that with distributed training can be achieved eventually, better results than those achieved in the local environment.

  3. Simulacin del proceso de biodegradacin de aguas residuales de la industria de carne mediante una red neuronal artificial perceptrn multicapa / Simulation of biodegradation process of wastewater from meat industry by means of a multilayer perceptron artificial neural network

    Scientific Electronic Library Online (English)

    Jos C, Crvelo Santana; Sidnei A, de Arajo; Joana P, M. Biazus; Roberto R, de Souza.

    2015-04-01

    Full Text Available En este trabajo se propone utilizar una Red Neuronal Artificial (RNA) Perceptrn Multicapa (PMC) para simular la variacin de la concentracin de protena de acuerdo con el tiempo y tambin para determinar la hora final del procedimiento, adems de los parmetros ptimos del proceso de biodegradaci [...] n de las protenas de un efluente de matadero. Para eso, han sido utilizadas las papanas, presentes en el ltex de la papaya (Carica papaya) con el objetivo de disminuir la concentracin de protenas de un efluente de matadero a pH (5 y 7) con una temperatura de (25 y 30 C) controlada. Los resultados mostraron que las papanas redujeron de 82% a 91% la concentracin de protena en 30 y 40 h de proceso. Las simulaciones con la RNA apuntaron que las condiciones perfectas fueron obtenidas a pH 5, con 30 C y en 35 h, en el cual se ha alcanzado una reduccin de 91% de la concentracin de protenas. Abstract in english In this paper, the use of a multilayer perceptron (MLP) artificial neural network (ANN) is proposed to simulate the variation of protein concentration according to the time and also to determine the end and optimal conditions of the biodegradation process of wastewater from meat industry. To reduce [...] the protein concentration, papains from Carica papaya latex have been used at controlled condition of pH (5 and 7) and temperature (25 and 30 C). Results showed that a reduction of 82 to 91% of protein concentration by the action of papains for 30 to 40 h of process time. Simulations showed that the best condition of the process occurred at pH 5, 30 C and 35 h, in which a maximum biodegradation of 91% was obtained.

  4. Landslide susceptibility assesssment in the Uttarakhand area (India) using GIS: a comparison study of prediction capability of naïve bayes, multilayer perceptron neural networks, and functional trees methods

    Science.gov (United States)

    Pham, Binh Thai; Tien Bui, Dieu; Pourghasemi, Hamid Reza; Indra, Prakash; Dholakia, M. B.

    2015-12-01

    The objective of this study is to make a comparison of the prediction performance of three techniques, Functional Trees (FT), Multilayer Perceptron Neural Networks (MLP Neural Nets), and Naïve Bayes (NB) for landslide susceptibility assessment at the Uttarakhand Area (India). Firstly, a landslide inventory map with 430 landslide locations in the study area was constructed from various sources. Landslide locations were then randomly split into two parts (i) 70 % landslide locations being used for training models (ii) 30 % landslide locations being employed for validation process. Secondly, a total of eleven landslide conditioning factors including slope angle, slope aspect, elevation, curvature, lithology, soil, land cover, distance to roads, distance to lineaments, distance to rivers, and rainfall were used in the analysis to elucidate the spatial relationship between these factors and landslide occurrences. Feature selection of Linear Support Vector Machine (LSVM) algorithm was employed to assess the prediction capability of these conditioning factors on landslide models. Subsequently, the NB, MLP Neural Nets, and FT models were constructed using training dataset. Finally, success rate and predictive rate curves were employed to validate and compare the predictive capability of three used models. Overall, all the three models performed very well for landslide susceptibility assessment. Out of these models, the MLP Neural Nets and the FT models had almost the same predictive capability whereas the MLP Neural Nets (AUC = 0.850) was slightly better than the FT model (AUC = 0.849). The NB model (AUC = 0.838) had the lowest predictive capability compared to other models. Landslide susceptibility maps were final developed using these three models. These maps would be helpful to planners and engineers for the development activities and land-use planning.

  5. El uso de perceptrones multicapa para la modelización estadística de series de tiempo no lineales de so2, en Salta Capital, Argentina The use of multilayer perceptrons for statistical modeling so2 non linear time series in Salta Capital, Argentina

    Directory of Open Access Journals (Sweden)

    Haydeé Elena Musso

    2013-01-01

    Full Text Available En este trabajo se realizó un estudio estadístico de variables físico químicas asociadas al fenómeno de contaminación ambiental, en particular concentración media mensual de SO2 , medidas en la ciudad Salta Capital, Argentina, simultáneamente a concentraciones de NO2 y O3 . Las series bajo estudio presentaban comportamientos dinámicos no lineales, datos atípicos y cambios estructurales, lo que hizo imposible modelarlas con tipologías econométricas tradiciones (AR, MA, ARMA, ARIMA, entre otras. Una solución eficiente que se encontró, hace uso de la teoría de los perceptrones multicapa. Mediante el modelo estructural de series de tiempo, esta solución se presenta como un proceso matemático iterativo que permite obtener un modelado final el cual tiene una muy alta confiabilidad (95%, para realizar pronoósticos a futuro sobre el comportamiento de la variable estudiada.In this paper a statistical study of phisical-chemistry variables connected with enviroment pollution, specifically SO2 monthly average concentration, measured in Salta Capital city, Argentina, together with NO2 and O3 concentrations, was made. Time series under study shown non linear dinamic behaviour, outliers and structural changes. Due to these it was impossible to use typical econometric typologies (AR, MA, ARMA, ARIMA, among others. An effective solution which uses multistep perceptrons theory was found. By using structural time series modelling, this solution is presented by an iterative mathematical process that allows us to obtain a final model with a high confidence level (95% in order to do the forecasting step on the studied variable.

  6. Prediction of Bladder Cancer Recurrences Using Artificial Neural Networks

    Science.gov (United States)

    Zulueta Guerrero, Ekaitz; Garay, Naiara Telleria; Lopez-Guede, Jose Manuel; Vilches, Borja Ayerdi; Iragorri, Eider Egilegor; Castaos, David Lecumberri; de La Hoz Rastrollo, Ana Beln; Pea, Carlos Pertusa

    Even if considerable advances have been made in the field of early diagnosis, there is no simple, cheap and non-invasive method that can be applied to the clinical monitorisation of bladder cancer patients. Moreover, bladder cancer recurrences or the reappearance of the tumour after its surgical resection cannot be predicted in the current clinical setting. In this study, Artificial Neural Networks (ANN) were used to assess how different combinations of classical clinical parameters (stage-grade and age) and two urinary markers (growth factor and pro-inflammatory mediator) could predict post surgical recurrences in bladder cancer patients. Different ANN methods, input parameter combinations and recurrence related output variables were used and the resulting positive and negative prediction rates compared. MultiLayer Perceptron (MLP) was selected as the most predictive model and urinary markers showed the highest sensitivity, predicting correctly 50% of the patients that would recur in a 2 year follow-up period.

  7. A Deterministic and Polynomial Modified Perceptron Algorithm

    Directory of Open Access Journals (Sweden)

    Olof Barr

    2006-01-01

    Full Text Available We construct a modified perceptron algorithm that is deterministic, polynomial and also as fast as previous known algorithms. The algorithm runs in time O(mn3lognlog(1/ρ, where m is the number of examples, n the number of dimensions and ρ is approximately the size of the margin. We also construct a non-deterministic modified perceptron algorithm running in timeO(mn2lognlog(1/ρ.

  8. Fault Diagnosis of Multilevel Cascaded Inverter Using Multi Layer Perceptron Network

    OpenAIRE

    E. Parimalasundar; N.Suthanthira Vanitha

    2015-01-01

    In this study, a fault diagnostic system in a multi-level inverter using a MLP network is developed. Using a mathematical model, it is difficult to diagnose a Multilevel-Inverter Drive (MLID) system, because MLID system complexity has a non-linear factor and it consist of many switching devices. Therefore neural network classification is applied to fault diagnosis of MLID system. Multilayer perceptron networks (MLP) are used to identify the type and location of occurring faults from inverter ...

  9. Identification of Non-Linear Structures using Recurrent Neural Networks

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R. K.; Hansen, H. I.

    Two different partially recurrent neural networks structured as Multi Layer Perceptrons (MLP) are investigated for time domain identification of a non-linear structure.......Two different partially recurrent neural networks structured as Multi Layer Perceptrons (MLP) are investigated for time domain identification of a non-linear structure....

  10. Best approximation by Heaviside perceptron networks.

    Science.gov (United States)

    Kainen, P; K?rkov, V; Vogt, A

    2000-09-01

    In Lp-spaces with p an integer from [1, infinity) there exists a best approximation mapping to the set of functions computable by Heaviside perceptron networks with n hidden units; however for p an integer from (1, infinity) such best approximation is not unique and cannot be continuous. PMID:11152201

  11. Classification of Parking Spots Using Multilayer Perceptron Networks

    Directory of Open Access Journals (Sweden)

    FALCAO, H. S.

    2013-12-01

    Full Text Available This project intends to develop a prototype for the identification of free spots in open air parking area where there is a good aerial view without obstacles, allowing for the identification of occupied and free spots. We used image processing techniques and pattern recognition using Artificial Neural Networks (ANN. In order to help implement the prototype, we used Matlab. In order to simulate the parking area, we created a model so that we could acquire the images using a webcam, process them, train the neural network, classify the spots and finally, show the results. The results show that it is viable to apply pattern recognition through image capture to classify parking spots

  12. FPGA Implementation of Multilayer Perceptron for Modeling of Photovoltaic panel

    International Nuclear Information System (INIS)

    The Number of electronic applications using artificial neural network-based solutions has increased considerably in the last few years. However, their applications in photovoltaic systems are very limited. This paper introduces the preliminary result of the modeling and simulation of photovoltaic panel based on neural network and VHDL-language. In fact, an experimental database of meteorological data (irradiation, temperature) and output electrical generation signals of the PV-panel (current and voltage) has been used in this study. The inputs of the ANN-PV-panel are the daily total irradiation and mean average temperature while the outputs are the current and voltage generated from the panel. Firstly, a dataset of 4x364 have been used for training the network. Subsequently, the neural network (MLP) corresponding to PV-panel is simulated using VHDL language based on the saved weights and bias of the network. Simulation results of the trained MLP-PV panel based on Matlab and VHDL are presented. The proposed PV-panel model based ANN and VHDL permit to evaluate the performance PV-panel using only the environmental factors and involves less computational efforts, and it can be used for predicting the output electrical energy from the PV-panel

  13. Classification of fuels using multilayer perceptron neural networks

    International Nuclear Information System (INIS)

    Electrical impedance data obtained with an array of conducting polymer chemical sensors was used by a neural network (ANN) to classify fuel adulteration. Real samples were classified with accuracy greater than 90% in two groups: approved and adulterated.

  14. Hybrid Evolutionary Algorithm for Multilayer Perceptron Networks with Competetive Performance

    Czech Academy of Sciences Publication Activity Database

    Neruda, Roman

    Los Alamitos : IEEE, 2007, s. 1620-1627. ISBN 978-1-4244-1339-3. [CEC 2007. Congress on Evolution ary Computation. Singapore (SG), 25.09.2007-28.09.2007] R&D Projects: GA AV ČR 1ET100300419 Institutional research plan: CEZ:AV0Z10300504 Keywords : hybrid algorithms * evolution ary learning * neural networks Subject RIV: IN - Informatics, Computer Science

  15. Representations of Boolean Functions by Perceptron Networks

    Czech Academy of Sciences Publication Activity Database

    Kůrková, Věra

    Prague : Institute of Computer Science AS CR, 2014 - (Kůrková, V.; Bajer, L.; Peška, L.; Vojtáš, R.; Holeňa, M.; Nehéz, M.), s. 68-70 ISBN 978-80-87136-19-5. [ITAT 2014. European Conference on Information Technologies - Applications and Theory /14./. Demänovská dolina (SK), 25.09.2014-29.09.2014] R&D Projects: GA MŠk(CZ) LD13002 Institutional support: RVO:67985807 Keywords : perceptron networks * model complexity * Boolean functions Subject RIV: IN - Informatics, Computer Science

  16. Optimal Capacity of the Blume-Emery-Griffiths perceptron

    OpenAIRE

    Bolle', D.; Castillo, I. Perez; Shim, G. M.

    2002-01-01

    A Blume-Emery-Griffiths perceptron model is introduced and its optimal capacity is calculated within the replica-symmetric Gardner approach, as a function of the pattern activity and the imbedding stability parameter. The stability of the replica-symmetric approximation is studied via the analogue of the Almeida-Thouless line. A comparison is made with other three-state perceptrons.

  17. Learning from correlated patterns by simple perceptrons

    International Nuclear Information System (INIS)

    Learning behavior of simple perceptrons is analyzed for a teacher-student scenario in which output labels are provided by a teacher network for a set of possibly correlated input patterns, and such that the teacher and student networks are of the same type. Our main concern is the effect of statistical correlations among the input patterns on learning performance. For this purpose, we extend to the teacher-student scenario a methodology for analyzing randomly labeled patterns recently developed in Shinzato and Kabashima 2008 J. Phys. A: Math. Theor. 41 324013. This methodology is used for analyzing situations in which orthogonality of the input patterns is enhanced in order to optimize the learning performance

  18. Core reactivity estimation in space reactors using recurrent dynamic networks

    Science.gov (United States)

    Parlos, Alexander G.; Tsai, Wei K.

    1991-01-01

    A recurrent multilayer perceptron network topology is used in the identification of nonlinear dynamic systems from only the input/output measurements. The identification is performed in the discrete time domain, with the learning algorithm being a modified form of the back propagation (BP) rule. The recurrent dynamic network (RDN) developed is applied for the total core reactivity prediction of a spacecraft reactor from only neutronic power level measurements. Results indicate that the RDN can reproduce the nonlinear response of the reactor while keeping the number of nodes roughly equal to the relative order of the system. As accuracy requirements are increased, the number of required nodes also increases, however, the order of the RDN necessary to obtain such results is still in the same order of magnitude as the order of the mathematical model of the system. It is believed that use of the recurrent MLP structure with a variety of different learning algorithms may prove useful in utilizing artificial neural networks for recognition, classification, and prediction of dynamic systems.

  19. Fault Diagnosis of Multilevel Cascaded Inverter Using Multi Layer Perceptron Network

    Directory of Open Access Journals (Sweden)

    E. Parimalasundar

    2015-02-01

    Full Text Available In this study, a fault diagnostic system in a multi-level inverter using a MLP network is developed. Using a mathematical model, it is difficult to diagnose a Multilevel-Inverter Drive (MLID system, because MLID system complexity has a non-linear factor and it consist of many switching devices. Therefore neural network classification is applied to fault diagnosis of MLID system. Multilayer perceptron networks (MLP are used to identify the type and location of occurring faults from inverter output voltage measurement. Here, MLP network based fault identification system for five level cascade H-bridge Multilevel Inverter (MLI is analyzed. The proposed system identifies the fault with a greater accuracy and the results to various input patterns are presented for easy comprehension.

  20. The Perceptron Algorithm: Image and Signal Decomposition, Compression, and Analysis by Iterative Gaussian Blurring

    CERN Document Server

    Vassiliadis, V S

    2006-01-01

    A novel algorithm for tunable compression to within the precision of reproduction targets, or storage, is proposed. The new algorithm is termed the `Perceptron Algorithm', which utilises simple existing concepts in a novel way, has multiple immediate commercial application aspects as well as it opens up a multitude of fronts in computational science and technology. The aims of this paper are to present the concepts underlying the algorithm, observations by its application to some example cases, and the identification of a multitude of potential areas of applications such as: image compression by orders of magnitude, signal compression including sound as well, image analysis in a multilayered detailed analysis, pattern recognition and matching and rapid database searching (e.g. face recognition), motion analysis, biomedical applications e.g. in MRI and CAT scan image analysis and compression, as well as hints on the link of these ideas to the way how biological memory might work leading to new points of view i...

  1. Stability of the replica symmetric solution in diluted perceptron learning

    International Nuclear Information System (INIS)

    We study the role played by dilution in the average behavior of a perceptron model with continuous coupling with the replica method. We analyze the stability of the replica symmetric solution as a function of the dilution field for the generalization and memorization problems. Thanks to a Gardner-like stability analysis we show that at any fixed ratio α between the number of patterns M and the dimension N of the perceptron (α = M/N), there exists a critical dilution field hc above which the replica symmetric ansatz becomes unstable. (letter)

  2. Stability analysis of discrete-time recurrent neural networks.

    Science.gov (United States)

    Barabanov, N E; Prokhorov, D V

    2002-01-01

    We address the problem of global Lyapunov stability of discrete-time recurrent neural networks (RNNs) in the unforced (unperturbed) setting. It is assumed that network weights are fixed to some values, for example, those attained after training. Based on classical results of the theory of absolute stability, we propose a new approach for the stability analysis of RNNs with sector-type monotone nonlinearities and nonzero biases. We devise a simple state-space transformation to convert the original RNN equations to a form suitable for our stability analysis. We then present appropriate linear matrix inequalities (LMIs) to be solved to determine whether the system under study is globally exponentially stable. Unlike previous treatments, our approach readily permits one to account for non-zero biases usually present in RNNs for improved approximation capabilities. We show how recent results of others on the stability analysis of RNNs can be interpreted as special cases within our approach. We illustrate how to use our approach with examples. Though illustrated on the stability analysis of recurrent multilayer perceptrons, the approach proposed can also be applied to other forms of time-lagged RNNs. PMID:18244432

  3. Convergence Analysis of Adaptive Recurrent Neural Network

    OpenAIRE

    Hong Li; Ali Setoodehnia

    2014-01-01

    This paper presents analysis of a modified Feed Forward Multilayer Perceptron (FMP) by inserting an ARMA (Auto Regressive Moving Average) model at each neuron (processor node) with the Backp ropagation learning algorithm. The stability analysis is presented to establish the convergence theory of the Back propagation algorithm based on the Lyapunov function. Furthermore, the analysis extends the Back propagation learning rule by introducing the adaptive learning factors. A rang...

  4. Chaotic diagonal recurrent neural network

    International Nuclear Information System (INIS)

    We propose a novel neural network based on a diagonal recurrent neural network and chaos, and its structure and learning algorithm are designed. The multilayer feedforward neural network, diagonal recurrent neural network, and chaotic diagonal recurrent neural network are used to approach the cubic symmetry map. The simulation results show that the approximation capability of the chaotic diagonal recurrent neural network is better than the other two neural networks. (interdisciplinary physics and related areas of science and technology)

  5. Efficient learning algorithm for quantum perceptron unitary weights

    OpenAIRE

    Seow, Kok-Leong; Behrman, Elizabeth; Steck, James

    2015-01-01

    For the past two decades, researchers have attempted to create a Quantum Neural Network (QNN) by combining the merits of quantum computing and neural computing. In order to exploit the advantages of the two prolific fields, the QNN must meet the non-trivial task of integrating the unitary dynamics of quantum computing and the dissipative dynamics of neural computing. At the core of quantum computing and neural computing lies the qubit and perceptron, respectively. We see that past implementat...

  6. A coherent perceptron for all-optical learning

    Energy Technology Data Exchange (ETDEWEB)

    Tezak, Nikolas; Mabuchi, Hideo [Stanford University, Edward L. Ginzton Laboratory, Stanford, CA (United States)

    2015-12-15

    We present nonlinear photonic circuit models for constructing programmable linear transformations and use these to realize a coherent perceptron, i.e., an all-optical linear classifier capable of learning the classification boundary iteratively from training data through a coherent feedback rule. Through extensive semi-classical stochastic simulations we demonstrate that the device nearly attains the theoretical error bound for a model classification problem. (orig.)

  7. Higher-order probabilistic perceptrons as Bayesian inference engines

    International Nuclear Information System (INIS)

    This letter makes explicit a structural connection between the Bayes optimal classifier operating on K binary input variables and corresponding two-layer perceptron having normalized output activities and couplings from input to output units of all orders up to K. Given a large and unbiased training set and an effective learning algorithm, such a neural network should be able to learn the statistics of the classification problem and match the a posteriori probabilities given by the Bayes optimal classifier. (author). 18 refs

  8. A coherent perceptron for all-optical learning

    International Nuclear Information System (INIS)

    We present nonlinear photonic circuit models for constructing programmable linear transformations and use these to realize a coherent perceptron, i.e., an all-optical linear classifier capable of learning the classification boundary iteratively from training data through a coherent feedback rule. Through extensive semi-classical stochastic simulations we demonstrate that the device nearly attains the theoretical error bound for a model classification problem. (orig.)

  9. FORECASTING ON FOREX MARKET WITH RBF AND PERCEPTRON NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    ALEXANDRA KOTTILOV

    2012-01-01

    Full Text Available This work deals with an alternative approach in financial modelling -artificial neural networks approach. The aim of this paper is to show that this type oftime series modelling is an excellent alternative to classical econometric modelling. Atfirst, neural networks using methods of supervised machine learning are discussed.After explaining theoretical basis of ANN, these models are then applied to specificexchange rate (AUD/USD. Finally, the comparison between statistical models andRBF and perceptron neural networks is made to illustrate the sense of using ANNmodels

  10. Limitations of One-Hidden-Layer Perceptron Networks

    Czech Academy of Sciences Publication Activity Database

    Kůrková, Věra

    Aachen & Charleston : Technical University & CreateSpace Independent Publishing Platform, 2015 - (Yaghob, J.), s. 167-171 ISBN 978-1-5151-2065-0. ISSN 1613-0073. - (CEUR Workshop Proceedings. V-1422). [ITAT 2015. Conference on Theory and Practice of Information Technologies /15./. Slovenský Raj (SK), 17.09.2015-21.09.2015] R&D Projects: GA MŠk(CZ) LD13002 Institutional support: RVO:67985807 Keywords : perceptron networks * model complexity * representations of finite mappings by neural networks Subject RIV: IN - Informatics, Computer Science

  11. Representations of highly-varying functions by perceptron networks

    Czech Academy of Sciences Publication Activity Database

    Kůrková, Věra

    North Charleston : CreateSpace Independent Publishing Platform, 2013 - (Vinař, T.; Holeňa, M.; Lexa, M.; Peška, L.; Vojtáš, P.), s. 73-76 ISBN 978-1-4909-5208-6. [ITAT 2013. Conference on Theory and Practice of Information Technologies. Donovaly (SK), 11.09.2013-15.09.2013] R&D Projects: GA ČR GAP202/11/1368 Institutional support: RVO:67985807 Keywords : one-hidden-layer networks * perceptrons * Boolean functions * network complexity Subject RIV: IN - Informatics, Computer Science

  12. A multi-layer feed-forward perceptron for microwave signals processing

    OpenAIRE

    Rouveure, R.; Faure, P.; Monod, M.O.

    2003-01-01

    This paper investigates the processing of radar signals using artificial neural networks. Today, the use of FMCW radar is considered to control the agricultural implements working depth, in order to overcome the limitations of sensors based on optical or ultrasound devices towards agricultural environment (dust, rain, etc.). The objective is to determine the radar-target distance R with a direct identification of the discrete-time radar signal Sb[n]. The neural network structure in a multi-la...

  13. The reactor safety study with help of artificial neuron networks (multilayer perceptrons)

    International Nuclear Information System (INIS)

    One deals with deposition of insulation large amounts on settling tank components that may result in malfunction of residual heat removal systems. Paper describes briefly simulation of pressure drops in confinement systems by means of an artificial neuron nets and compares the simulation data with the experiment ones

  14. Electron/pion identification in the CBM TRD using a multilayer perceptron

    International Nuclear Information System (INIS)

    The problem of electron/pion identification in the CBM experiment based on the measurements of energy losses and transition radiation in the TRD detector is discussed. A possibility to solve such a problem by applying an artificial neural network (ANN) is considered. As input information for the network we used both the samples of energy losses of pions or electrons in the TRD absorbers and the 'clever' variable obtained on the basis of the original data. We show that usage of this new variable permits one to reach a reliable level of particle recognition no longer than after 10-20 training epochs; there are practically no fluctuations against the trend, and the needed level of pions suppression is obtained under the condition of a minimal loss of electrons

  15. Hybrid Optimized Back propagation Learning Algorithm For Multi-layer Perceptron

    OpenAIRE

    Chakraborty, Mriganka; Ghosh, Arka

    2012-01-01

    Standard neural network based on general back propagation learning using delta method or gradient descent method has some great faults like poor optimization of error-weight objective function, low learning rate, instability .This paper introduces a hybrid supervised back propagation learning algorithm which uses trust-region method of unconstrained optimization of the error objective function by using quasi-newton method .This optimization leads to more accurate weight update system for mini...

  16. Handwritten Arabic Numeral Recognition using a Multi Layer Perceptron

    CERN Document Server

    Das, Nibaran; Saha, Sudip; Haque, Syed Sahidul

    2010-01-01

    Handwritten numeral recognition is in general a benchmark problem of Pattern Recognition and Artificial Intelligence. Compared to the problem of printed numeral recognition, the problem of handwritten numeral recognition is compounded due to variations in shapes and sizes of handwritten characters. Considering all these, the problem of handwritten numeral recognition is addressed under the present work in respect to handwritten Arabic numerals. Arabic is spoken throughout the Arab World and the fifth most popular language in the world slightly before Portuguese and Bengali. For the present work, we have developed a feature set of 88 features is designed to represent samples of handwritten Arabic numerals for this work. It includes 72 shadow and 16 octant features. A Multi Layer Perceptron (MLP) based classifier is used here for recognition handwritten Arabic digits represented with the said feature set. On experimentation with a database of 3000 samples, the technique yields an average recognition rate of 94....

  17. Intelligent control of HVAC systems. Part II: perceptron performance analysis

    Directory of Open Access Journals (Sweden)

    Ioan URSU

    2013-09-01

    Full Text Available This is the second part of a paper on intelligent type control of Heating, Ventilating, and Air-Conditioning (HVAC systems. The whole study proposes a unified approach in the design of intelligent control for such systems, to ensure high energy efficiency and air quality improving. In the first part of the study it is considered as benchmark system a single thermal space HVAC system, for which it is assigned a mathematical model of the controlled system and a mathematical model(algorithm of intelligent control synthesis. The conception of the intelligent control is of switching type, between a simple neural network, a perceptron, which aims to decrease (optimize a cost index,and a fuzzy logic component, having supervisory antisaturating role for neuro-control. Based on numerical simulations, this Part II focuses on the analysis of system operation in the presence only ofthe neural control component. Working of the entire neuro-fuzzy system will be reported in a third part of the study.

  18. Recurrent varicocele.

    Science.gov (United States)

    Rotker, Katherine; Sigman, Mark

    2016-01-01

    Varicocele recurrence is one of the most common complications associated with varicocele repair. A systematic review was performed to evaluate varicocele recurrence rates, anatomic causes of recurrence, and methods of management of recurrent varicoceles. The PubMed database was evaluated using keywords "recurrent" and "varicocele" as well as MESH criteria "recurrent" and "varicocele." Articles were not included that were not in English, represented single case reports, focused solely on subclinical varicocele, or focused solely on a pediatric population (age varicocele repair from 0% to 35%. Anatomy of recurrence can be defined by venography. Management of varicocele recurrence can be surgical or via embolization. PMID:26806078

  19. Multilayer Networks

    CERN Document Server

    Kivelä, Mikko; Barthelemy, Marc; Gleeson, James P; Moreno, Yamir; Porter, Mason A

    2013-01-01

    Most real and engineered systems include multiple subsystems and layers of connectivity, and it is important to take such features into account to try to obtain a complete understanding of these systems. It is thus necessary to generalize "traditional" network theory by developing (and validating) a framework and associated tools to study multilayer systems in a comprehensive fashion. The origins of such efforts occurred several decades ago, but now the study of multilayer networks has become one of the major directions in network science. In this paper, we discuss the history of multilayer networks (and related concepts) and then review the exploding body of work on such networks. To unify the disparate terminology in the large body of recent work, we discuss a general framework for multilayer networks, construct a dictionary of terminology to relate the numerous existing concepts to each other, and provide a thorough discussion that compares, contrasts, and translates between related notions such as multila...

  20. Perceptron-like computation based on biologically-inspired neurons with heterosynaptic mechanisms

    Science.gov (United States)

    Kaluza, Pablo; Urdapilleta, Eugenio

    2014-10-01

    Perceptrons are one of the fundamental paradigms in artificial neural networks and a key processing scheme in supervised classification tasks. However, the algorithm they provide is given in terms of unrealistically simple processing units and connections and therefore, its implementation in real neural networks is hard to be fulfilled. In this work, we present a neural circuit able to perform perceptron's computation based on realistic models of neurons and synapses. The model uses Wang-Buzsáki neurons with coupling provided by axodendritic and axoaxonic synapses (heterosynapsis). The main characteristics of the feedforward perceptron operation are conserved, which allows to combine both approaches: whereas the classical artificial system can be used to learn a particular problem, its solution can be directly implemented in this neural circuit. As a result, we propose a biologically-inspired system able to work appropriately in a wide range of frequencies and system parameters, while keeping robust to noise and error.

  1. Quantum perceptron over a field and neural network architecture selection in a quantum computer.

    Science.gov (United States)

    da Silva, Adenilton José; Ludermir, Teresa Bernarda; de Oliveira, Wilson Rosa

    2016-04-01

    In this work, we propose a quantum neural network named quantum perceptron over a field (QPF). Quantum computers are not yet a reality and the models and algorithms proposed in this work cannot be simulated in actual (or classical) computers. QPF is a direct generalization of a classical perceptron and solves some drawbacks found in previous models of quantum perceptrons. We also present a learning algorithm named Superposition based Architecture Learning algorithm (SAL) that optimizes the neural network weights and architectures. SAL searches for the best architecture in a finite set of neural network architectures with linear time over the number of patterns in the training set. SAL is the first learning algorithm to determine neural network architectures in polynomial time. This speedup is obtained by the use of quantum parallelism and a non-linear quantum operator. PMID:26878722

  2. Recurrent croup.

    OpenAIRE

    Hide, D W; Guyer, B M

    1985-01-01

    Thirty one of 486 children followed from birth had recurrent croup in the first four years of life. Twenty one were boys, and 10 girls. Recurrent croup occurred significantly more often in families with a positive history of allergy but was not significantly associated with the initial feeding method.

  3. Gas Sensors Characterization and Multilayer Perceptron (MLP) Hardware Implementation for Gas Identification Using a Field Programmable Gate Array (FPGA)

    OpenAIRE

    Mokhtar Attari; Mounir Bouhedda; Fayçal Benrekia

    2013-01-01

    This paper develops a primitive gas recognition system for discriminating between industrial gas species. The system under investigation consists of an array of eight micro-hotplate-based SnO2 thin film gas sensors with different selectivity patterns. The output signals are processed through a signal conditioning and analyzing system. These signals feed a decision-making classifier, which is obtained via a Field Programmable Gate Array (FPGA) with Very High-Speed Integrated Circuit Hardware D...

  4. Modeling of gamma ray energy-absorption buildup factors for thermoluminescent dosimetric materials using multilayer perceptron neural network

    DEFF Research Database (Denmark)

    Kucuk, Nil; Manohara, S.R.; Hanagodimath, S.M.; Gerward, L.

    2013-01-01

    for penetration depths up to 10 mfp (mean-free-path). The MLPNNs have been trained by a Levenberg–Marquardt learning algorithm. The developed model is in 99% agreement with the ANSI/ANS-6.4.3 standard data set. Furthermore, the model is fast and does not require tremendous computational efforts. The...

  5. Automated torso organ segmentation from 3D CT images using structured perceptron and dual decomposition

    Science.gov (United States)

    Nimura, Yukitaka; Hayashi, Yuichiro; Kitasaka, Takayuki; Mori, Kensaku

    2015-03-01

    This paper presents a method for torso organ segmentation from abdominal CT images using structured perceptron and dual decomposition. A lot of methods have been proposed to enable automated extraction of organ regions from volumetric medical images. However, it is necessary to adjust empirical parameters of them to obtain precise organ regions. This paper proposes an organ segmentation method using structured output learning. Our method utilizes a graphical model and binary features which represent the relationship between voxel intensities and organ labels. Also we optimize the weights of the graphical model by structured perceptron and estimate the best organ label for a given image by dynamic programming and dual decomposition. The experimental result revealed that the proposed method can extract organ regions automatically using structured output learning. The error of organ label estimation was 4.4%. The DICE coefficients of left lung, right lung, heart, liver, spleen, pancreas, left kidney, right kidney, and gallbladder were 0.91, 0.95, 0.77, 0.81, 0.74, 0.08, 0.83, 0.84, and 0.03, respectively.

  6. Learning by random walks in the weight space of the Ising perceptron

    International Nuclear Information System (INIS)

    Several variants of a stochastic local search process for constructing the synaptic weights of an Ising perceptron are studied. In this process, binary patterns are sequentially presented to the Ising perceptron and are then learned as the synaptic weight configuration is modified through a chain of single- or double-weight flips within the compatible weight configuration space of the earlier learned patterns. This process is able to reach a storage capacity of α≈0.63 for pattern length N = 101 and α≈0.41 for N = 1001. If in addition a relearning process is exploited, the learning performance is further improved to a storage capacity of α≈0.80 for N = 101 and α≈0.42 for N = 1001. We found that, for a given learning task, the solutions constructed by the random walk learning process are separated by a typical Hamming distance, which decreases with the constraint density α of the learning task; at a fixed value of α, the width of the Hamming distance distribution decreases with N

  7. Recurrent miscarriage

    OpenAIRE

    Duckitt, Kirsten; Qureshi, Aysha

    2008-01-01

    Recurrent miscarriage is the spontaneous loss of three or more consecutive pregnancies with the same biological father in the first trimester; it affects 1% to 2% of women, in half of whom there is no identifiable cause. Overall, 75% of affected women will have a successful subsequent pregnancy, but this rate falls for older mothers and with increasing number of miscarriages.Antiphospholipid syndrome, with anticardiolipin or lupus anticoagulant antibodies, is present in 15% of women with r...

  8. Isomorphisms in Multilayer Networks

    CERN Document Server

    Kivelä, Mikko

    2015-01-01

    We extend the concept of graph isomorphisms to multilayer networks, and we identify multiple types of isomorphisms. For example, in multilayer networks with a single "aspect" (i.e., type of layering), permuting vertex labels, layer labels, and both of types of layers each yield a different type of isomorphism. We discuss how multilayer network isomorphisms naturally lead to defining isomorphisms in any type of network that can be represented as a multilayer network. This thereby yields isomorphisms for multiplex networks, temporal networks, networks with both such features, and more. We reduce each of the multilayer network isomorphism problems to a graph isomorphism problem, and we use this reduction to prove that the multilayer network isomorphism problem is computationally equally hard as the graph isomorphism problem. One can thus use software that has been developed to solve graph isomorphism problems as a practical means for solving multilayer network isomorphism problems.

  9. Inference from correlated patterns: a unified theory for perceptron learning and linear vector channels

    International Nuclear Information System (INIS)

    A framework to analyze inference performance in densely connected single-layer feed-forward networks is developed for situations where a given data set is composed of correlated patterns. The framework is based on the assumption that the left and right singular value bases of the given pattern matrix are generated independently and uniformly from Haar measures. This assumption makes it possible to characterize the objective system by a single function of two variables which is determined by the eigenvalue spectrum of the cross-correlation matrix of the pattern matrix. Links to existing methods for analysis of perceptron learning and Gaussian linear vector channels and an application to a simple but nontrivial problem are also shown

  10. Multilayer Insulation Material Guidelines

    Science.gov (United States)

    Finckenor, M. M.; Dooling, D.

    1999-01-01

    Multilayer Insulation Material Guidelines provides data on multilayer insulation materials used by previous spacecraft such as Spacelab and the Long-Duration Exposure Facility and outlines other concerns. The data presented in the document are presented for information only. They can be used as guidelines for multilayer insulation design for future spacecraft provided the thermal requirements of each new design and the environmental effects on these materials are taken into account.

  11. A morphological perceptron with gradient-based learning for Brazilian stock market forecasting.

    Science.gov (United States)

    Araújo, Ricardo de A

    2012-04-01

    Several linear and non-linear techniques have been proposed to solve the stock market forecasting problem. However, a limitation arises from all these techniques and is known as the random walk dilemma (RWD). In this scenario, forecasts generated by arbitrary models have a characteristic one step ahead delay with respect to the time series values, so that, there is a time phase distortion in stock market phenomena reconstruction. In this paper, we propose a suitable model inspired by concepts in mathematical morphology (MM) and lattice theory (LT). This model is generically called the increasing morphological perceptron (IMP). Also, we present a gradient steepest descent method to design the proposed IMP based on ideas from the back-propagation (BP) algorithm and using a systematic approach to overcome the problem of non-differentiability of morphological operations. Into the learning process we have included a procedure to overcome the RWD, which is an automatic correction step that is geared toward eliminating time phase distortions that occur in stock market phenomena. Furthermore, an experimental analysis is conducted with the IMP using four complex non-linear problems of time series forecasting from the Brazilian stock market. Additionally, two natural phenomena time series are used to assess forecasting performance of the proposed IMP with other non financial time series. At the end, the obtained results are discussed and compared to results found using models recently proposed in the literature. PMID:22391234

  12. Implementation of a spike-based perceptron learning rule using TiO2-x memristors.

    Science.gov (United States)

    Mostafa, Hesham; Khiat, Ali; Serb, Alexander; Mayr, Christian G; Indiveri, Giacomo; Prodromakis, Themis

    2015-01-01

    Synaptic plasticity plays a crucial role in allowing neural networks to learn and adapt to various input environments. Neuromorphic systems need to implement plastic synapses to obtain basic "cognitive" capabilities such as learning. One promising and scalable approach for implementing neuromorphic synapses is to use nano-scale memristors as synaptic elements. In this paper we propose a hybrid CMOS-memristor system comprising CMOS neurons interconnected through TiO2-x memristors, and spike-based learning circuits that modulate the conductance of the memristive synapse elements according to a spike-based Perceptron plasticity rule. We highlight a number of advantages for using this spike-based plasticity rule as compared to other forms of spike timing dependent plasticity (STDP) rules. We provide experimental proof-of-concept results with two silicon neurons connected through a memristive synapse that show how the CMOS plasticity circuits can induce stable changes in memristor conductances, giving rise to increased synaptic strength after a potentiation episode and to decreased strength after a depression episode. PMID:26483629

  13. Implementation of a spike-based perceptron learning rule using TiO2?x memristors

    Science.gov (United States)

    Mostafa, Hesham; Khiat, Ali; Serb, Alexander; Mayr, Christian G.; Indiveri, Giacomo; Prodromakis, Themis

    2015-01-01

    Synaptic plasticity plays a crucial role in allowing neural networks to learn and adapt to various input environments. Neuromorphic systems need to implement plastic synapses to obtain basic cognitive capabilities such as learning. One promising and scalable approach for implementing neuromorphic synapses is to use nano-scale memristors as synaptic elements. In this paper we propose a hybrid CMOS-memristor system comprising CMOS neurons interconnected through TiO2?x memristors, and spike-based learning circuits that modulate the conductance of the memristive synapse elements according to a spike-based Perceptron plasticity rule. We highlight a number of advantages for using this spike-based plasticity rule as compared to other forms of spike timing dependent plasticity (STDP) rules. We provide experimental proof-of-concept results with two silicon neurons connected through a memristive synapse that show how the CMOS plasticity circuits can induce stable changes in memristor conductances, giving rise to increased synaptic strength after a potentiation episode and to decreased strength after a depression episode. PMID:26483629

  14. The Multidimensional Cube Recurrence

    CERN Document Server

    Henriques, Andre

    2007-01-01

    We introduce a recurrence which we term the multidimensional cube recurrence, generalizing the octahedron recurrence studied by Propp, Fomin and Zelevinsky, Speyer, and Fock and Goncharov and the three-dimensional cube recurrence studied by Fomin and Zelevinsky, and Carroll and Speyer. The states of this recurrence are indexed by tilings of a polygon with rhombi, and the variables in the recurrence are indexed by vertices of these tilings. We travel from one state of the recurrence to another by performing elementary flips. We show that the values of the recurrence are independent of the order in which we perform the flips; this proof involves nontrivial combinatorial results about rhombus tilings which may be of independent interest. We then show that the multidimensional cube recurrence exhibits the Laurent phenomenon -- any variable is given by a Laurent polynomial in the other variables. We recognize a special case of the multidimensional cube recurrence as giving explicit equations for the isotropic Gras...

  15. Effective electromagnetic shielding in multilayer printed circuit boards

    Science.gov (United States)

    Wiles, K. G.; Moe, J. L.

    Multilayer printed circuit boards have proven to be recurrent abettors of electromagnetic coupling problems created by the incessantly faster response times in integrated circuit technologies. Coupling within multilayer boards has not only inhibited meeting certain EMI requirements but has also precipitated 'self-inflicted' malfunctions commonly experienced during development of avionic systems. A recent avionic system, interfacing two asynchronous processors through a fourteen-layer motherboard, permitted coupling through ground plane connector apertures of sufficient amplitude and duration as to cause unintentional intercommunication and system malfunctions. The coupling mechanism and ground plane modifications which reduced this coupling by 40 dB and eliminated the incompatibility are discussed in this paper

  16. The Normalized Radial Basis Function Neural Network and its Relation to the Perceptron

    OpenAIRE

    Grabec, I.

    2007-01-01

    The normalized radial basis function neural network emerges in the statistical modeling of natural laws that relate components of multivariate data. The modeling is based on the kernel estimator of the joint probability density function pertaining to given data. From this function a governing law is extracted by the conditional average estimator. The corresponding nonparametric regression represents a normalized radial basis function neural network and can be related with the multi-layer perc...

  17. On the conditions for the existence of Perfect Learning and power law in learning from stochastic examples by Ising perceptrons

    CERN Document Server

    Uezu, T

    2001-01-01

    In a previous letter, we studied learning from stochastic examples by perceptrons with Ising weights in the framework of statistical mechanics. Under the one-step replica symmetry breaking ansatz, the behaviours of learning curves were classified according to some local property of the rules by which examples were drawn. Further, the conditions for the existence of the Perfect Learning together with other behaviors of the learning curves were given. In this paper, we give the detailed derivation about these results and further argument about the Perfect Learning together with extensive numerical calculations.

  18. Core reactivity estimation in space reactors using recurrent dynamic networks

    International Nuclear Information System (INIS)

    A recurrent Multi Layer Perceptron (MLP) network topology is used in the identification of nonlinear dynamic systems from only the input/output measurements. This effort is part of a research program devoted in developing real-time diagnostics and predictive control techniques for large-scale complex nonlinear dynamic systems. The identification is performed in the discrete time domain, with the learning algorithm being a modified form of the Back Propagation (BP) rule. The Recurrent Dynamic Network (RDN) developed is applied for the total core reactivity prediction of a spacecraft reactor from only neutronic power level measurements. Results indicate that the RDN can reproduce the nonlinear response of the reactor while keeping the number of nodes roughly equal to the relative order of the system. As accuracy requirements are increased, the number of required nodes also increases, however, the order of the RDN necessary to obtain such results is still in the same order of magnitude as the order of the matematical model of the system. There are a number of issues identified regarding the behavior of the RDN, which at this point are unresolved and require further research. Nevertheless, it is believed that use of the recurrent MLP structure with a variety of different learning algorithms may prove useful in utilizing artifical neural networks (ANNs) for recognition, classification and prediction of dynamic systems

  19. Scattering from a multilayered chiral sphere using an iterative method

    Science.gov (United States)

    Shang, Qing-Chao; Wu, Zhen-Sen; Qu, Tan; Li, Zheng-Jun; Bai, Lu

    2016-04-01

    An iterative method for electromagnetic scattering from a multilayered chiral sphere is presented based on Lorenz-Mie regime. Electromagnetic fields in each region are expanded in terms of spherical vector wave functions. To calculate the scattering coefficients of the fields in outer space, an iterative form is constructed according to the coefficients equations obtained by the boundary condition on each layer. The iterative relations are expressed in forms of ratios and logarithmic derivatives of Riccati-Bessel functions, which can be calculated conveniently by their recurrence relations. The theory and codes are verified by comparing the scattered fields with those of a multilayered isotropic achiral sphere, and those of a single layered chiral sphere. Scattered fields of multilayered chiral spheres are presented and discussed, including a large sized case and a Gaussian beam incidence case.

  20. Recurrent groin hernia

    OpenAIRE

    Cox, P. J.; Leach, R. D.; Ellis, Harold

    1981-01-01

    One hundred consecutive recurrences following repair of inguinal hernias have been studied; 62 were direct, 30 indirect, 7 pantaloon and one a femoral hernia. Half the indirect recurrences occurred within a year of repair and probably represented failure to detect a small indirect sac. Later indirect recurrences probably represented failure to repair the internal ring. Nine of the direct hernias were medial funicular recurrences and represented failure to anchor the darn medially. The rest of...

  1. Advances in Artificial Neural Networks – Methodological Development and Application

    OpenAIRE

    Yanbo Huang

    2009-01-01

    Artificial neural networks as a major soft-computing technology have been extensively studied and applied during the last three decades. Research on backpropagation training algorithms for multilayer perceptron networks has spurred development of other neural network training algorithms for other networks such as radial basis function, recurrent network, feedback network, and unsupervised Kohonen self-organizing network. These networks, especially the multilayer perceptron network with a back...

  2. Control of Multilayer Networks

    CERN Document Server

    Menichetti, Giulia; Bianconi, Ginestra

    2015-01-01

    The controllability of a network is a theoretical problem of relevance in a variety of contexts ranging from financial markets to the brain. Until now, network controllability has been characterized only on isolated networks, while the vast majority of complex systems are formed by multilayer networks. Here we build a theoretical framework for the linear controllability of multilayer networks by mapping the problem into a combinatorial matching problem. We found that correlating the external signals in the different layers can significantly reduce the multiplex network robustness to node removal, as it can be seen in conjunction with a hybrid phase transition occurring in interacting Poisson networks. Moreover we observe that multilayer networks can stabilize the fully controllable multiplex network configuration that can be stable also when the full controllability of the single network is not stable.

  3. Control of Multilayer Networks.

    Science.gov (United States)

    Menichetti, Giulia; Dall'Asta, Luca; Bianconi, Ginestra

    2016-01-01

    The controllability of a network is a theoretical problem of relevance in a variety of contexts ranging from financial markets to the brain. Until now, network controllability has been characterized only on isolated networks, while the vast majority of complex systems are formed by multilayer networks. Here we build a theoretical framework for the linear controllability of multilayer networks by mapping the problem into a combinatorial matching problem. We found that correlating the external signals in the different layers can significantly reduce the multiplex network robustness to node removal, as it can be seen in conjunction with a hybrid phase transition occurring in interacting Poisson networks. Moreover we observe that multilayer networks can stabilize the fully controllable multiplex network configuration that can be stable also when the full controllability of the single network is not stable. PMID:26869210

  4. Controlling light with plasmonic multilayers

    DEFF Research Database (Denmark)

    Orlov, Alexey A.; Zhukovsky, Sergei; Iorsh, Ivan V.; Belov, Pavel A.

    2014-01-01

    Recent years have seen a new wave of interest in layered media - namely, plasmonic multilayers - in several emerging applications ranging from transparent metals to hyperbolic metamaterials. In this paper, we review the optical properties of such subwavelength metal-dielectric multilayered...... metamaterials and describe their use for light manipulation at the nanoscale. While demonstrating the recently emphasized hallmark effect of hyperbolic dispersion, we put special emphasis to the comparison between multilayered hyperbolic metamaterials and more broadly defined plasmonic-multilayer metamaterials...

  5. Investigation of periodic multilayers

    CERN Document Server

    Bodnarchuck, V; Ignatovich, V; Veres, T; Yaradaykin, S

    2009-01-01

    Periodic multilayers of various periods were prepared according to an algorithm proposed by the authors. The reflectivity properties of these systems were investigated using neutron reflectometry.The obtained experimental results were compared with the theoretical expectations. In first approximation, the results proved the main features of the theoretical predictions. These promising results initiate further research of such systems.

  6. Multi-Layer Perceptrons and Support Vector Machines for Detection Problems with Low False Alarm Requirements: an Eight-Month Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Chen, B; Hickling, T; Krnjajic, M; Hanley, W; Clark, G; Nitao, J; Knapp, D; Hiller, L; Mugge, M

    2007-01-09

    In this project, the basic problem is to automatically separate test samples into one of two categories: clean or corrupt. This type of classification problem is known as a two-class classification problem or detection problem. In what follows, we refer to clean examples as negative examples and corrupt examples as positive examples. In a detection problem, a classifier decision on any one sample can be grouped into one of four decision categories: true negative, true positive, false negative and false positive. These four categories are illustrated by Table 1. True negatives and true positives are cases where the classifier has made the correct decision. False positives are cases where the classifier decides positive when the true nature of the sample was negative, and false negatives are cases where the classifier decides negative when the sample was actually positive. To evaluate the performance of a classifier, we run the classifier on all the samples of a data set and then count all the instances of true negatives, true positives, false negatives, and false positives. All of the performance metrics in this report are then formed from a combination of these four basic decision categories.

  7. Geospatial scenario based modelling of urban and agricultural intrusions in Ramsar wetland Deepor Beel in Northeast India using a multi-layer perceptron neural network

    Science.gov (United States)

    Mozumder, Chitrini; Tripathi, Nitin K.

    2014-10-01

    In recent decades, the world has experienced unprecedented urban growth which endangers the green environment in and around urban areas. In this work, an artificial neural network (ANN) based model is developed to predict future impacts of urban and agricultural expansion on the uplands of Deepor Beel, a Ramsar wetland in the city area of Guwahati, Assam, India, by 2025 and 2035 respectively. Simulations were carried out for three different transition rates as determined from the changes during 2001-2011, namely simple extrapolation, Markov Chain (MC), and system dynamic (SD) modelling, using projected population growth, which were further investigated based on three different zoning policies. The first zoning policy employed no restriction while the second conversion restriction zoning policy restricted urban-agricultural expansion in the Guwahati Municipal Development Authority (GMDA) proposed green belt, extending to a third zoning policy providing wetland restoration in the proposed green belt. The prediction maps were found to be greatly influenced by the transition rates and the allowed transitions from one class to another within each sub-model. The model outputs were compared with GMDA land demand as proposed for 2025 whereby the land demand as produced by MC was found to best match the projected demand. Regarding the conservation of Deepor Beel, the Landscape Development Intensity (LDI) Index revealed that wetland restoration zoning policies may reduce the impact of urban growth on a local scale, but none of the zoning policies was found to minimize the impact on a broader base. The results from this study may assist the planning and reviewing of land use allocation within Guwahati city to secure ecological sustainability of the wetlands.

  8. Recurrence in Quantum Mechanics

    OpenAIRE

    Duvenhage, Rocco

    2002-01-01

    We first compare the mathematical structure of quantum and classical mechanics when both are formulated in a C*-algebraic framework. By using finite von Neumann algebras, a quantum mechanical analogue of Liouville's theorem is then proposed. We proceed to study Poincare recurrence in C*-algebras by mimicking the measure theoretic setting. The results are interpreted as recurrence in quantum mechanics, similar to Poincare recurrence in classical mechanics.

  9. Fungus Infections: Preventing Recurrence

    Science.gov (United States)

    ... Favorite Name: Category: Share: Yes No, Keep Private Fungus Infections: Preventing Recurrence Share | Doctors have excellent treatments for skin fungus infections that occur on the feet, nails, groin, ...

  10. Optimal Recurrence Grammars

    CERN Document Server

    Graben, Peter beim; Fröhlich, Flavio

    2015-01-01

    We optimally estimate the recurrence structure of a multivariate time series by Markov chains obtained from recurrence grammars. The goodness of fit is assessed with a utility function derived from the stochastic Markov transition matrix. It assumes a local maximum for the distance threshold of the optimal recurrence grammar. We validate our approach by means of the nonlinear Lorenz system and its linearized stochastic surrogates. Finally we apply our optimization procedure to the segmentation of neurophysiological time series obtained from anesthetized animals. We propose the number of optimal recurrence domains as a statistic for classifying an animals' state of consciousness.

  11. Recurrent Takotsubo Cardiomyopathy Related to Recurrent Thyrotoxicosis.

    Science.gov (United States)

    Patel, Keval; Griffing, George T; Hauptman, Paul J; Stolker, Joshua M

    2016-04-01

    Takotsubo cardiomyopathy, or transient left ventricular apical ballooning syndrome, is characterized by acute left ventricular dysfunction caused by transient wall-motion abnormalities of the left ventricular apex and mid ventricle in the absence of obstructive coronary artery disease. Recurrent episodes are rare but have been reported, and several cases of takotsubo cardiomyopathy have been described in the presence of hyperthyroidism. We report the case of a 55-year-old woman who had recurrent takotsubo cardiomyopathy, documented by repeat coronary angiography and evaluations of left ventricular function, in the presence of recurrent hyperthyroidism related to Graves disease. After both episodes, the patient's left ventricular function returned to normal when her thyroid function normalized. These findings suggest a possible role of thyroid-hormone excess in the pathophysiology of some patients who have takotsubo cardiomyopathy. PMID:27127432

  12. Thermopower of multilayer graphene

    OpenAIRE

    Hao, Lei; Lee, T. K.

    2010-01-01

    We systematically calculate thermopower of biased and unbiased multilayer grphene systems. The effect of screening to a bias field perpendicular to the graphene planes is taken into account self-consistently under the Hartree approximation. The model including nearest neighbor hopping and the more complete Slonczewski-Weiss-McClure (SWMcC) model are both considered for a comparison. The effect of impurity scattering is studied for monolayer and unbiased bilayer graphene and is treated in term...

  13. Clustering Multilayer Networks

    OpenAIRE

    Afsarmanesh Tehrani, Nazanin

    2016-01-01

    Detecting community structure is an important methodology to study complex networks. Community detection methods can be divided into two main categories: partitioning methods and overlapping clustering methods. In partitioning methods, each node can belong to at most one community while overlapping clustering methods allow communities with overlapping nodes as well. Community detection is not only a problem in single networks today, but also in multilayer networks where several networks with ...

  14. Multilayer graphene waveguides

    OpenAIRE

    Smirnova, Daria; Iorsh, Ivan; Shadrivov, Ilya; Kivshar, Yuri

    2014-01-01

    We study dispersion properties of TM-polarized electromagnetic waves guided by a multilayer graphene metamaterial. We demonstrate that both dispersion and localization of the guided modes can be efficiently controlled by changing the number of layers in the structure. Remarkably, we find that in the long wavelength limit, the dispersion of the fundamental mode of the N-layer graphene structure coincides with the dispersion of a plasmon mode supported by a single graphene layer, but with N tim...

  15. Screening in multilayer graphene

    OpenAIRE

    van Gelderen, R.; Olsen, Richard; de Morais Smith, C.

    2013-01-01

    In this paper, we study the static polarization in ABC-stacked multilayer graphene. Since the density of states diverges for these systems if the number of layers exceeds three, screening effects are expected to be important. In the random phase approximation, screening can be included through the polarization. We derive an analytical integral expression for the polarization in both the full-band model and an effective two-band model. Numerical evaluation of these integrals is very time consu...

  16. A comparative study of different feature sets for recognition of handwritten Arabic numerals using a Multi Layer Perceptron

    CERN Document Server

    Das, Nibaran; Sarkar, Ram; Basu, Subhadip

    2010-01-01

    The work presents a comparative assessment of seven different feature sets for recognition of handwritten Arabic numerals using a Multi Layer Perceptron (MLP) based classifier. The seven feature sets employed here consist of shadow features, octant centroids, longest runs, angular distances, effective spans, dynamic centers of gravity, and some of their combinations. On experimentation with a database of 3000 samples, the maximum recognition rate of 95.80% is observed with both of two separate combinations of features. One of these combinations consists of shadow and centriod features, i. e. 88 features in all, and the other shadow, centroid and longest run features, i. e. 124 features in all. Out of these two, the former combination having a smaller number of features is finally considered effective for applications related to Optical Character Recognition (OCR) of handwritten Arabic numerals. The work can also be extended to include OCR of handwritten characters of Arabic alphabet.

  17. The eternal recurrence today

    CERN Document Server

    Neves, J C S

    2015-01-01

    In this work we have carried out an approach between the nonsingular scientific cosmologies (without the initial singularity, the big bang), specially the cyclic models, and the Nietzsche's thought of the eternal recurrence. Moreover, we have pointed out reasons for the Nietzsche's search for scientific proofs about the eternal recurrence in the decade of 1880's.

  18. Recurrent aphthous stomatitis

    Directory of Open Access Journals (Sweden)

    L Preeti

    2011-01-01

    Full Text Available Recurrent aphthous ulcers are common painful mucosal conditions affecting the oral cavity. Despite their high prevalence, etiopathogenesis remains unclear. This review article summarizes the clinical presentation, diagnostic criteria, and recent trends in the management of recurrent apthous stomatitis.

  19. Polarizing multilayer spectrometer for neutrons

    International Nuclear Information System (INIS)

    Polarizing neutron monochromators were prepared by sputtering thin-film multilayers with d-spacings from 40 to 85A on large float-glass substrates. Peak reflectivities as great as 90% and polarizing efficiencies of 98% were measured. Increased angular acceptances were obtained by fabricating multilayers with multiple d- spacings. A planned polarized beam spectrometer which incorporates the multilayers and which has a variable energy resolution independent of angular beam divergence is described

  20. XUV multilayered optics for astrophysics

    OpenAIRE

    Catura, R. C.; Golub, Leon

    1988-01-01

    High quality multilayered optics operating in the extreme ultraviolet are now being fabricated by a number of laboratories and their use in astronomical observations from space has already begun. Many other applications are planned and future instruments involving multilayers hold great promise for the field of astrophysics. This paper presents an overview of the current status of multilayer-based astronomical instrumentation, observations that have already occured and some plans for the future.

  1. [Recurrent fevers in childhood].

    Science.gov (United States)

    Piram, Maryam; Kon-Paut, Isabelle

    2015-12-01

    Recurrent fevers are defined as multiple stereotypical febrile episodes separated by spontaneous symptom-free intervals and occurring for months and years. Hereditary recurrent fevers are rare prototype Mendelian diseases due to inherited mutations in genes encoding partners of the innate immunity. Recurrent episodes of fever plus acute features of inflammation starting during childhood with family history are the main clues for suspecting HRF. Their common associated complication is AA amyloidosis. The diagnosis is made on clinical grounds but the genetic diagnosis may contribute in most cases of monogenic hereditary recurrent fevers. Recurrent fevers must be distinguished from intermittent fevers, mostly infectious, characterized by variation in associated symptoms from episode-to-episode and without periodicity. PMID:26549686

  2. Multi-layers castings

    OpenAIRE

    J. Szajnar; P. Wrbel; T. Wrbel

    2010-01-01

    In paper is presented the possibility of making of multi-layers cast steel castings in result of connection of casting and welding coating technologies. First layer was composite surface layer on the basis of Fe-Cr-C alloy, which was put directly in founding process of cast carbon steel 200450 with use of preparation of mould cavity method. Second layer were padding welds, which were put with use of TIG Tungsten Inert Gas surfacing by welding technology with filler on Ni matrix, Ni and Co ...

  3. Recurrent corneal perforation due to chronic graft versus host disease; a clinicopathologic report

    Directory of Open Access Journals (Sweden)

    Mehrdad Mohammadpour

    2016-01-01

    Conclusion: Patients with GVHD are at risk of severe dry eye and subsequent corneal vascularization. Recurrent and recalcitrant corneal perforation resistant to cyanoacrylate glue and multilayer AMT may occur. Proper systemic and ocular management alongside close collaboration with the hematologist is strongly recommended to control the condition.

  4. Recurrence and algorithmic information

    OpenAIRE

    C. Bonanno; Galatolo, S.; Isola, S

    2003-01-01

    In this paper we initiate a somewhat detailed investigation of the relationships between quantitative recurrence indicators and algorithmic complexity of orbits in weakly chaotic dynamical systems. We mainly focus on examples.

  5. Recurrent erysipelas after radiotherapy

    International Nuclear Information System (INIS)

    A case of recurrent erysipelas is reported in a female with a history of vulvectomy and radiotherapy to the pelvis. On the basis of a review of the literature, risk factors for this condition and recommended treatments are discussed

  6. Ultrahard Multilayer Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Chrzan, D.C.; Dugger, M.; Follstaedt, D.M.; Friedman, Lawrence H.; Friedmann, T.A.; Knapp, J.A.; McCarty, K.F.; Medlin, D.L.; Mirkarimi, P.B.; Missert, N.; Newcomer, P.P.; Sullivan, J.P.; Tallant, D.R.

    1999-05-01

    We have developed a new multilayer a-tC material that is thick stress-free, adherent, low friction, and with hardness and stiffness near that of diamond. The new a-tC material is deposited by J pulsed-laser deposition (PLD) at room temperature, and fully stress-relieved by a short thermal anneal at 600°C. A thick multilayer is built up by repeated deposition and annealing steps. We measured 88 GPa hardness, 1100 GPa Young's modulus, and 0.1 friction coefficient (under high load). Significantly, these results are all well within the range reported for crystalline diamond. In fact, this material, if considered separate from crystalline diamond, is the 2nd hardest material known to man. Stress-free a-tC also has important advantages over thin film diamond; namely, it is smooth, processed at lower temperature, and can be grown on a much broader range of substrates. This breakthrough will enable a host of applications that we are actively pursuing in MEMs, sensors, LIGA, etc.

  7. Ultrahard Multilayer Coatings

    International Nuclear Information System (INIS)

    We have developed a new multilayer a-tC material that is thick stress-free, adherent, low friction, and with hardness and stiffness near that of diamond. The new a-tC material is deposited by J pulsed-laser deposition (PLD) at room temperature, and fully stress-relieved by a short thermal anneal at 600 ampersand deg;C. A thick multilayer is built up by repeated deposition and annealing steps. We measured 88 GPa hardness, 1100 GPa Young's modulus, and 0.1 friction coefficient (under high load). Significantly, these results are all well within the range reported for crystalline diamond. In fact, this material, if considered separate from crystalline diamond, is the 2nd hardest material known to man. Stress-free a-tC also has important advantages over thin film diamond; namely, it is smooth, processed at lower temperature, and can be grown on a much broader range of substrates. This breakthrough will enable a host of applications that we are actively pursuing in MEMs, sensors, LIGA, etc

  8. Dynamic recurrent neural networks

    OpenAIRE

    Pearlmutter, Barak A

    1990-01-01

    We survey learning algorithms for recurrent neural networks with hidden units and attempt to put the various techniques into a common framework. We discuss fixpoint learning algorithms, namely recurrent backpropagation and deterministic Boltzmann Machines, and non-fixpoint algorithms, namely backpropagation through time, Elman's history cutoff nets, and Jordan's output feedback architecture. Forward propagation, an online technique that uses adjoint equations, is also discussed. In many cases...

  9. Recurrences of strange attractors

    Indian Academy of Sciences (India)

    E J Ngamga; A Nandi; R Ramaswamy; M C Romano; M Thiel; J Kurths

    2008-06-01

    The transitions from or to strange nonchaotic attractors are investigated by recurrence plot-based methods. The techniques used here take into account the recurrence times and the fact that trajectories on strange nonchaotic attractors (SNAs) synchronize. The performance of these techniques is shown for the Heagy-Hammel transition to SNAs and for the fractalization transition to SNAs for which other usual nonlinear analysis tools are not successful.

  10. Kinetic Study of anti-HIV drugs by Thermal Decomposition Analysis: A Multilayer Artificial Neural Network Propose

    CERN Document Server

    Ferreira, B D L; Sebastião, R C O; Yoshida, M I; Mussel, W N; Fialho, S L; Barbosa, J

    2016-01-01

    Kinetic study by thermal decomposition of antiretroviral drugs, Efavirenz (EFV) and Lamivudine (3TC), usually present in the HIV cocktail, can be done by individual adjustment of the solid decomposition models. However, in some cases unacceptable errors are found using this methodology. To circumvent this problem, here is proposed to use a multilayer perceptron neural network (MLP), with an appropriate algorithm, which constitutes a linearization of the network by setting weights between the input layer and the intermediate one and the use of Kinetic models as activation functions of neurons in the hidden layer. The interconnection weights between that intermediate layer and output layer determines the contribution of each model in the overall fit of the experimental data. Thus, the decomposition is assumed to be a phenomenon that can occur following different kinetic processes. In the investigated data, the kinetic thermal decomposition process was best described by R1 and D4 model for all temperatures to EF...

  11. Hyperhomocysteinemia in Recurrent Miscarriage

    International Nuclear Information System (INIS)

    Objective: An elevated total plasma homocysteine level has been suggested as a possible risk factor in women suffering from recurrent pregnancy loss. The current study was undertaken to assess the association between homocysteine, folate, cobalamin (vitamin B12) and the risk of recurrent pregnancy loss. Design: Case . control study Materials and Methods: The study included 57 non-pregnant Egyptian women. They were classified according to their obstetric history into 2 groups: 32 cases with at least two consecutive miscarriages (Study group), and 25 cases with normal obstetric history (Control group). All cases were tested for plasma total homocysteine, serum folate and cobalamin (vitamin B12). Results: The fasting total homocysteine was significantly higher in the study group as compared to the control group. While the median concentrations for the vitamins studied were significantly lower in women of the study group as compared to the controls. Elevated homocysteine and reduced vitamin B12 can be considered risk factors for recurrent miscarriage with odds ratio (OR) and 95% confidence intervals (95% CI) of 1.839 (1.286, 2.63) and 1.993 (1.346, 2.951) respectively in the group of recurrent miscarriages. The OR (95% CI) in the study population for low serum folate concentrations was 1.23 (0.776, 2.256). Conclusion: Elevated homocysteine and reduced serum vitamin B12 are risk factors for recurrent miscarriage. Low serum folate did not seem a risk factor for recurrent miscarriage. Testing for homocysteine levels in women suffering from unexplained recurrent miscarriage and pre-conceptional supplementation with vitamin B12 might be beneficial to improve pregnancy outcome

  12. Comments on ‘Temporal significant wave height estimation from wind speed by perceptron Kalman filtering’ by A. Altunkaynak and M. Ozger, Ocean Engineering, Vol. 31(10); 2004,1245-1255

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.

    significant wave height estimation from wind speed by perceptron Kalman filtering? by A Altunkaynak and M Ozger, Ocean Engineering, 2004, 31, 1245-1255 Discussion by S Mandal* Ocean Engineering Division, National Institute of Oceanography, Dona Paula... the restrictive uses of regression method, especially for predicting wind generated waves. The authors have established the two layered Perceptron based on Kalman Filtering (PKF) technique to estimate the significant wave height (Hs) amounts for future time...

  13. Multi-layers castings

    Directory of Open Access Journals (Sweden)

    J. Szajnar

    2010-01-01

    Full Text Available In paper is presented the possibility of making of multi-layers cast steel castings in result of connection of casting and welding coating technologies. First layer was composite surface layer on the basis of Fe-Cr-C alloy, which was put directly in founding process of cast carbon steel 200450 with use of preparation of mould cavity method. Second layer were padding welds, which were put with use of TIG Tungsten Inert Gas surfacing by welding technology with filler on Ni matrix, Ni and Co matrix with wolfram carbides WC and on the basis on Fe-Cr-C alloy, which has the same chemical composition with alloy, which was used for making of composite surface layer. Usability for industrial applications of surface layers of castings were estimated by criterion of hardness and abrasive wear resistance of type metal-mineral.

  14. Multilayered folding with voids

    CERN Document Server

    Dodwell, Timothy; Peletier, Mark; Budd, Chris

    2011-01-01

    In the deformation of layered materials such as geological strata, or stacks of paper, mechanical properties compete with the geometry of layering. Smooth, rounded corners lead to voids between the layers, while close packing of the layers results in geometrically-induced curvature singularities. When voids are penalized by external pressure, the system is forced to trade off these competing effects, leading to sometimes striking periodic patterns. In this paper we construct a simple model of geometrically nonlinear multi-layered structures under axial loading and pressure confinement, with non-interpenetration conditions separating the layers. Energy minimizers are characterized as solutions of a set of fourth-order nonlinear differential equations with contact-force Lagrange multipliers, or equivalently of a fourth-order free-boundary problem. We numerically investigate the solutions of this free boundary problem, and compare them with the periodic solutions observed experimentally.

  15. Diffusion Processes on Multilayer Networks

    CERN Document Server

    Salehi, Mostafa; Marzolla, Moreno; Montesi, Danilo; Siyari, Payam; Magnani, Matteo

    2014-01-01

    Several systems can be modelled as sets of interdependent networks or networks with multiple types of connections, here generally called multilayer networks. Diffusion processes like the propagation of information or the spreading of diseases are fundamental phenomena occurring in these networks. However, while the study of diffusion processes in single networks has received a great deal of interest from various disciplines for over a decade, diffusion on multilayer networks is still a young and promising research area presenting many challenging research issues. In this paper we review the main models, results and applications of multilayer diffusion and discuss some promising research directions.

  16. Sistema de anlise de ativos atravs de redes neurais de mltiplas camadas. Asset analysis system using multilayer neural networks

    Directory of Open Access Journals (Sweden)

    Vnia Medianeira Flores Costa

    2012-04-01

    Full Text Available When investors decide to adventure through stock markets they search for a method to provide safety on making decision. In fact, there is no precise way to know which stocks will became a profitable investiment. Technical analysis is a discipline that support the investors on making decisions. Such a discipline uses a set of tools and statistical methods to forecast the markets movement. Such a paper presents the develpment of a robotical Trade System, using a heuristic method. The system has a Neural Network multilayer perceptron, trained with an algorithm for back propagation error. Thus, approaching to the technical analysis without emotional aspects, using the Neural Network forecast on supporting the decisions of a investor on stock market. In analyzing the results of the neural network can be seen that the neural network got a result of 42.6% higher than the diagnostic of the technical analysis.Quando investidores decidem se aventurar pelo mercado de renda varivel, como pelo mercado de aes, buscam um mtodo de ter mais segurana na tomada de deciso. Na prtica, no h como saber quais ativos tornar-se-o um investimento lucrativo. No mercado acionrio, a Anlise Tcnica procura auxiliar o investidor na tomada de deciso. Para isso, utiliza-se de ferramentas e de mtodos estatsticos para tentar predizer os movimentos do mercado. Este artigo apresenta o desenvolvimento de um Trade System robtico, utilizando um mtodo heurstico. O sistema conta com uma rede neural multilayer perceptron, treinada com o algoritmo de retro propagao de erro, aproximando-se da anlise tcnica sem o fator emoo. Ao avaliaros resultados darede neural, podeser visto que amesma obteve um resultadode 42,6% maior do queo diagnstico daanlise tcnica.

  17. Recurrent Fever in Children

    Science.gov (United States)

    Torreggiani, Sofia; Filocamo, Giovanni; Esposito, Susanna

    2016-01-01

    Children presenting with recurrent fever may represent a diagnostic challenge. After excluding the most common etiologies, which include the consecutive occurrence of independent uncomplicated infections, a wide range of possible causes are considered. This article summarizes infectious and noninfectious causes of recurrent fever in pediatric patients. We highlight that, when investigating recurrent fever, it is important to consider age at onset, family history, duration of febrile episodes, length of interval between episodes, associated symptoms and response to treatment. Additionally, information regarding travel history and exposure to animals is helpful, especially with regard to infections. With the exclusion of repeated independent uncomplicated infections, many infective causes of recurrent fever are relatively rare in Western countries; therefore, clinicians should be attuned to suggestive case history data. It is important to rule out the possibility of an infectious process or a malignancy, in particular, if steroid therapy is being considered. After excluding an infectious or neoplastic etiology, immune-mediated and autoinflammatory diseases should be taken into consideration. Together with case history data, a careful physical exam during and between febrile episodes may give useful clues and guide laboratory investigations. However, despite a thorough evaluation, a recurrent fever may remain unexplained. A watchful follow-up is thus mandatory because new signs and symptoms may appear over time. PMID:27023528

  18. Structure and Swelling Behaviour of Polyelectrolyte Multilayers

    OpenAIRE

    Dodoo, Samuel

    2011-01-01

    In this thesis, the relation between structure, growth and swelling in water of polyelectrolyte multilayers are investigated. Polyelectrolyte multilayers are fabricated by alternating adsorption of polyanions and polycations on a silicon substrate. The multilayer is sensitive to external stimuli, which often counteracts the stability of the multilayer. Also the many applications of polyelectrolyte multilayers have made the interphase between the substrate and the film bulk to be of interest. ...

  19. Recurrent Novae - A Review

    CERN Document Server

    Mukai, Koji

    2014-01-01

    In recent years, recurrent nova eruptions are often observed very intensely in wide range of wavelengths from radio to optical to X-rays. Here I present selected highlights from recent multi-wavelength observations. The enigma of T Pyx is at the heart of this paper. While our current understanding of CV and symbiotic star evolution can explain why certain subset of recurrent novae have high accretion rate, that of T Pyx must be greatly elevated compared to the evolutionary mean. At the same time, we have extensive data to be able to estimate how the nova envelope was ejected in T Pyx, and it turns to be a rather complex tale. One suspects that envelope ejection in recurrent and classical novae in general is more complicated than the textbook descriptions. At the end of the review, I will speculate that these two may be connected.

  20. Multilayered Magnetic Gelatin Membrane Scaffolds.

    Science.gov (United States)

    Samal, Sangram K; Goranov, Vitaly; Dash, Mamoni; Russo, Alessandro; Shelyakova, Tatiana; Graziosi, Patrizio; Lungaro, Lisa; Riminucci, Alberto; Uhlarz, Marc; Bañobre-López, Manuel; Rivas, Jose; Herrmannsdörfer, Thomas; Rajadas, Jayakumar; De Smedt, Stefaan; Braeckmans, Kevin; Kaplan, David L; Dediu, V Alek

    2015-10-21

    A versatile approach for the design and fabrication of multilayer magnetic scaffolds with tunable magnetic gradients is described. Multilayer magnetic gelatin membrane scaffolds with intrinsic magnetic gradients were designed to encapsulate magnetized bioagents under an externally applied magnetic field for use in magnetic-field-assisted tissue engineering. The temperature of the individual membranes increased up to 43.7 °C under an applied oscillating magnetic field for 70 s by magnetic hyperthermia, enabling the possibility of inducing a thermal gradient inside the final 3D multilayer magnetic scaffolds. On the basis of finite element method simulations, magnetic gelatin membranes with different concentrations of magnetic nanoparticles were assembled into 3D multilayered scaffolds. A magnetic-gradient-controlled distribution of magnetically labeled stem cells was demonstrated in vitro. This magnetic biomaterial-magnetic cell strategy can be expanded to a number of different magnetic biomaterials for various tissue engineering applications. PMID:26451743

  1. Acute recurrent polyhydramnios

    DEFF Research Database (Denmark)

    Rode, Line; Bundgaard, Anne; Skibsted, Lillian; Odum, Lars; Jrgensen, Connie; Langhoff-Roos, Jens

    2007-01-01

    Acute recurrent polyhydramnios is a rare occurrence characterized by a poor fetal outcome. This is a case report describing a 34-year-old woman presenting with acute recurrent polyhydramnios. Treatment with non-steroidal anti-inflammatory drugs (NSAID) and therapeutic amniocenteses was initiated...... immediately and resulted in a decreased amniotic fluid production from 30 weeks' gestation. Even after the discontinuation of NSAID treatment, the amniotic fluid production normalized, and the woman delivered a healthy boy at 39 weeks 2 days' gestation. Amniotic prolactin was measured at three occasions using...

  2. Anomalous Magnetoresistance in Fibonacci Multilayers

    OpenAIRE

    Machado, L. D.; Bezerra, C. G.; Correa, M. A.; Chesman, C.; Pearson, J. E.; Hoffmann, A.

    2012-01-01

    The present paper theoretically investigates magnetoresistance curves in quasiperiodic magnetic multilayers for two different growth directions, namely [110] and [100]. We considered identical ferromagnetic layers separated by non-magnetic layers with two different thicknesses chosen based on the Fibonacci sequence. Using parameters for Fe/Cr multilayers, four terms were included in our description of the magnetic energy: Zeeman, cubic anisotropy, bilinear and biquadratic couplings. The minim...

  3. Image Reconstruction Using Multi Layer Perceptron MLP And Support Vector Machine SVM Classifier And Study Of Classification Accuracy

    OpenAIRE

    Shovasis Kumar Biswas; Mohammad Mahmudul Alam Mia

    2015-01-01

    Abstract Support Vector Machine SVM and back-propagation neural network BPNN has been applied successfully in many areas for example rule extraction classification and evaluation. In this paper we studied the back-propagation algorithm for training the multilayer artificial neural network and a support vector machine for data classification and image reconstruction aspects. A model focused on SVM with Gaussian RBF kernel is utilized here for data classification. Back propagation neural networ...

  4. Recurrent Neural Network Grammars

    OpenAIRE

    Dyer, Chris; Kuncoro, Adhiguna; Ballesteros, Miguel; Smith, Noah A.

    2016-01-01

    We introduce recurrent neural network grammars, probabilistic models of sentences with explicit phrase structure. We explain efficient inference procedures that allow application to both parsing and language modeling. Experiments show that they provide better parsing in English than any single previously published supervised generative model and better language modeling than state-of-the-art sequential RNNs in English and Chinese.

  5. Lung Cancer Indicators Recurrence

    Science.gov (United States)

    This study describes prognostic factors for lung cancer spread and recurrence, as well as subsequent risk of death from the disease. The investigators observed that regardless of cancer stage, grade, or type of lung cancer, patients in the study were more

  6. On Solving Linear Recurrences

    Science.gov (United States)

    Dobbs, David E.

    2013-01-01

    A direct method is given for solving first-order linear recurrences with constant coefficients. The limiting value of that solution is studied as "n to infinity." This classroom note could serve as enrichment material for the typical introductory course on discrete mathematics that follows a calculus course.

  7. Multilayer optical calculations

    CERN Document Server

    Byrnes, Steven J

    2016-01-01

    When light hits a multilayer planar stack, it is reflected, refracted, and absorbed in a way that can be derived from the Fresnel equations. The analysis is treated in many textbooks, and implemented in many software programs, but certain aspects of it are difficult to find explicitly and consistently worked out in the literature. Here, we derive the formulas underlying the transfer-matrix method of calculating the optical properties of these stacks, including oblique-angle incidence, absorption-vs-position profiles, and ellipsometry parameters. We discuss and explain some strange consequences of the formulas in the situation where the incident and/or final (semi-infinite) medium are absorptive, such as calculating $T>1$ in the absence of gain. We also discuss some implementation details like complex-plane branch cuts. Finally, we derive modified formulas for including one or more "incoherent" layers, i.e. very thick layers in which interference can be neglected. This document was written in conjunction with ...

  8. Diagnostic problems in recurrent lymphogranulomatosis

    International Nuclear Information System (INIS)

    Report on the incidence of recurrences, the time necessary for complete remission, and the sites of recurrences in 333 patients with demonstrated lymphogranulomatosis. Suggestion of an examination scheme considering clinical data and laboratory findings for early diagnosis of recurrences. Among the image-producing methods, sonography and CT are of special importance besides thorax examination, lymphography, and bone scintigraphy. (orig.)

  9. Recurrent hyperphosphatemic tumoural calcinosis

    Science.gov (United States)

    Amit, Sonal; Agarwal, Asha; Nigam, Anand; Rao, Yashwant Kumar

    2012-01-01

    Tumoural calcinosis (TC) is a benign gradually developing disorder that can occur in a variety of clinical settings, characterised by subcutaneous deposition of calcium phosphate with or without giant cell reaction. We describe a case of 11-year-old girl presenting with recurrent hard swellings in the vicinity of shoulder and hip joints associated with elevated serum phosphate and normal serum calcium levels. TC has been mainly reported from Africa, with very few cases reported from India. After the diagnosis of hyperphosphatemic TC was established, the patient was treated with oral sevelamer and is under constant follow-up to detect recurrence, if any. The present case highlights the fact that although an uncommon lesion, TC must be considered in the differential diagnosis of subcutaneous hard lump in the vicinity of a joint. PMID:23010461

  10. Training Recurrent Networks

    DEFF Research Database (Denmark)

    Pedersen, Morten With

    Training recurrent networks is generally believed to be a difficult task. Excessive training times and lack of convergence to an acceptable solution are frequently reported. In this paper we seek to explain the reason for this from a numerical point of view and show how to avoid problems when...... training. In particular we investigate ill-conditioning, the need for and effect of regularization and illustrate the superiority of second-order methods for training...

  11. Recurrent Neural Network Regularization

    OpenAIRE

    Zaremba, Wojciech; Sutskever, Ilya; Vinyals, Oriol

    2014-01-01

    We present a simple regularization technique for Recurrent Neural Networks (RNNs) with Long Short-Term Memory (LSTM) units. Dropout, the most successful technique for regularizing neural networks, does not work well with RNNs and LSTMs. In this paper, we show how to correctly apply dropout to LSTMs, and show that it substantially reduces overfitting on a variety of tasks. These tasks include language modeling, speech recognition, image caption generation, and machine translation.

  12. Recurrent Batch Normalization

    OpenAIRE

    Cooijmans, Tim; Ballas, Nicolas; Laurent, César; Gülçehre, Çağlar; Courville, Aaron

    2016-01-01

    We propose a reparameterization of LSTM that brings the benefits of batch normalization to recurrent neural networks. Whereas previous works only apply batch normalization to the input-to-hidden transformation of RNNs, we demonstrate that it is both possible and beneficial to batch-normalize the hidden-to-hidden transition, thereby reducing internal covariate shift between time steps. We evaluate our proposal on various sequential problems such as sequence classification, language modeling an...

  13. Multilayer monochromators for neutron scattering

    International Nuclear Information System (INIS)

    In an earlier paper Schoenborn, Caspar, and Kammerer (J. Appl. Cryst. 7, 508-10(1974)) reported the fabrication of thin film monochromators for neutrons. They showed that a multilayer consisting of alternating films of two materials acts as a good monochromator with large and adjustable periodicity and wide bandwidth. The diffraction properties of these multilayers have been studied with the objective of using them as monochromators, filters and polarizers for neutrons. A theoretical understanding of these multilayers has been developed by using the kinematical and dynamical approaches. In order to compare these expressions with the observed properties, the effects of beam divergence and wavelength distribution for the spectrometer have been determined. The influence of some aperiodicity on the diffraction data has also been studied within the framework of kinematical theory. (auth)

  14. Structural reducibility of multilayer networks

    Science.gov (United States)

    de Domenico, Manlio; Nicosia, Vincenzo; Arenas, Alexandre; Latora, Vito

    2015-04-01

    Many complex systems can be represented as networks consisting of distinct types of interactions, which can be categorized as links belonging to different layers. For example, a good description of the full protein-protein interactome requires, for some organisms, up to seven distinct network layers, accounting for different genetic and physical interactions, each containing thousands of protein-protein relationships. A fundamental open question is then how many layers are indeed necessary to accurately represent the structure of a multilayered complex system. Here we introduce a method based on quantum theory to reduce the number of layers to a minimum while maximizing the distinguishability between the multilayer network and the corresponding aggregated graph. We validate our approach on synthetic benchmarks and we show that the number of informative layers in some real multilayer networks of protein-genetic interactions, social, economical and transportation systems can be reduced by up to 75%.

  15. Monocyte activation on polyelectrolyte multilayers.

    Science.gov (United States)

    Hwang, Jason J; Jelacic, Sandra; Samuel, Newton T; Maier, Ronald V; Campbell, Charles T; Castner, David G; Hoffman, Allan S; Stayton, Patrick S

    2005-01-01

    The adherence and activation of primary human monocytes was investigated on a polyelectrolyte multilayer film containing hyaluronic acid (HA) and poly-L-lysine (PLL). The sequential layer-by-layer deposition of the multilayer film was characterized by surface plasmon resonance. Eight alternating bilayers displayed an effective thickness of 16.15 nm with a total polymer coverage of 2.10 microg/cm2. For cell studies, HA-PLL multilayers were constructed on tissue culture polystyrene (TCPS) substrates and characterized by time of flight second ion mass spectrometry (ToF-SIMS) analysis. Principal component analysis of the ToF-SIMS spectra resolved no significant difference in surface chemistry between PLL-terminated and HA-terminated multilayer surfaces. Monocyte adhesion on PLL- and HA-terminated surfaces was measured by the lactate dehydrogenase assay and showed a significant decrease in cell adhesion after 24 h incubation. Cell viability measured by Live/Dead fluorescent staining showed significant cell death in the adherent cell population over these 24 h. Tumor necrosis factor-alpha (TNF-alpha) production, a measure of monocyte activation, was quantified by ELISA and normalized to the number of adherent monocytes. The activation of monocytes on PLL-terminated and HA-terminated surfaces was nearly identical, and both surfaces had TNF-alpha levels that were 8-fold higher than TCPS. These results demonstrate that sufficient PLL had diffused into the surface layer to direct monocyte adherence and to induce cytokine activation and cell death on the HA-terminated multilayer films. The diffusion of the second multilayer component to the coating surface should, thus, be taken into account in the design of polyelectrolyte-based biomaterial coating strategies. PMID:15794488

  16. Transfer matrices for multilayer structures

    International Nuclear Information System (INIS)

    We consider four of the transfer matrices defined to deal with multilayer structures. We deduce algorithms to calculate them numerically, in a simple and neat way. We illustrate their application to semi-infinite systems using SGFM formulae. These algorithms are of fast convergence and allow a calculation of bulk-, surface- and inner-layers band structure in good agreement with much more sophisticated calculations. Supermatrices, interfaces and multilayer structures can be calculated in this way with a small computational effort. (author). 10 refs

  17. Recurrent cerebral thrombosis

    International Nuclear Information System (INIS)

    Neuroradiological techniques were used to elucidate pathophysiology of recurrent cerebral thrombosis. Twenty-two patients with cerebral thrombosis who suffered a second attack under stable conditions more than 22 days after the initial stroke were studied. Hypertension, diabetes mellitus, and hypercholesterolemia were also seen in 20, 8, and 12 patients, respectively. The patients were divided into three groups according to their symptoms: (I) symptoms differed between the first and second strokes (n=12); (II) initial symptoms were suddenly deteriorated (n=6); and (III) symptoms occurring in groups I and II were seen (n=4). In group I, contralateral hemiparesis or suprabulbar palsy was often associated with the initial hemiparesis. The time of recurrent stroke varied from 4 months to 9 years. CT and MRI showed not only lacunae in both hemispheres, but also deep white-matter ischemia of the centrum semi-ovale. In group II, hemiparesis or visual field defect was deteriorated early after the initial stroke. In addition, neuroimaging revealed that infarction in the posterior cerebral artery was progressed on the contralateral side, or that white matter lesion in the middle artery was enlarged in spite of small lesion in the left cerebral hemisphere. All patients in group III had deterioration of right hemiparesis associated with aphasia. CT, MRI, SPECT, and angiography indicated deep white-matter ischemia caused by main trunk lesions in the left hemisphere. Group III seemed to be equivalent to group II, except for laterality of the lesion. Neuroradiological assessment of the initial stroke may help to predict the mode of recurrence, although pathophysiology of cerebral thrombosis is complicated and varies from patient to patient. (N.K.)

  18. Equine recurrent airway obstruction

    Directory of Open Access Journals (Sweden)

    Artur Niedźwiedź

    2014-10-01

    Full Text Available Equine Recurrent Airway Obstruction (RAO, also known as heaves or broken wind, is one of the most common disease in middle-aged horses. Inflammation of the airway is inducted by organic dust exposure. This disease is characterized by neutrophilic inflammation, bronchospasm, excessive mucus production and pathologic changes in the bronchiolar walls. Clinical signs are resolved in 3-4 weeks after environmental changes. Horses suffering from RAO are susceptible to allergens throughout their lives, therefore they should be properly managed. In therapy the most importanthing is to eliminate dustexposure, administration of corticosteroids and use bronchodilators to improve pulmonary function.

  19. Recurrent Spatial Transformer Networks

    DEFF Research Database (Denmark)

    Sønderby, Søren Kaae; Sønderby, Casper Kaae; Maaløe, Lars; Winther, Ole

    2015-01-01

    We integrate the recently proposed spatial transformer network (SPN) [Jaderberg et. al 2015] into a recurrent neural network (RNN) to form an RNN-SPN model. We use the RNN-SPN to classify digits in cluttered MNIST sequences. The proposed model achieves a single digit error of 1.5% compared to 2.......9% for a convolutional networks and 2.0% for convolutional networks with SPN layers. The SPN outputs a zoomed, rotated and skewed version of the input image. We investigate different down-sampling factors (ratio of pixel in input and output) for the SPN and show that the RNN-SPN model is able to down...

  20. Management of recurrent Crohn's disease.

    Science.gov (United States)

    van Hogezand, R A; Bemelman, W A

    1998-12-01

    After partial small bowel or colonic resection for Crohn's disease, recurrence frequently follows. Within half a year 60-73% of patients have endoscopic recurrence. This percentage increases substantially in as time passes. Symptoms will not always be present when endoscopic lesions are detected. The etiology of recurrent Crohn's disease is unknown. Some studies show that initial complications or extra-intestinal manifestations are more frequently seen in patients with a recurrence. The recurrent pattern of the lesions is also comparable to the pre-surgical state. The length of recurrent ileal inflammation after ileocolonic resection correlates with the pre-surgical extent of the disease. Some investigators have found electron-microscopic lesions in histologically unaffected resection margins demonstrating the presence of lesions. Luminal factors probably plays an important role as bypassing an anastomosis prevents an endoscopic recurrence. Some factors are considered to be important to increase the chance of a recurrence. A more aggressive disease may lead to earlier recurrence. Onset of disease at a younger age, a short pre-operative time, and localization, might play an important role. Smoking certainly influences the clinical, endoscopic and surgical recurrence. The number of daily cigarettes smoked and the duration of smoking, significantly increases the risk of recurrence. The type of surgery (kind of anastomosis, multiple anastomoses, length of resection) are not important. A longer macroscopic disease-free resection margin or presence of granuloma does not influence the recurrence rate. Also, the presence of microscopic disease at the margin is not important. Prevention of recurrent disease can be provided by administrating sulphasalazine, 5-aminosalicylic acid or metronidazole. For this reason, prophylactic medication after surgical resection seems appropriate. PMID:9883012

  1. New developments in Ni/Ti multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, I.; Hoghoj, P. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    It is now 20 years since super-mirrors were first used as a neutron optical element. Since then the field of multilayer neutron-optics has matured with multilayers finding their way to application in many neutron scattering instruments. However, there is still room for progress in terms of multilayer quality, performance and application. Along with work on multilayers for neutron polarisation Ni/Ti super-mirrors have been optimised. The state-of-the-art Ni/Ti super-mirror performance and the results obtained in two neutron-optics applications of Ni/Ti multilayers are presented. (author).

  2. Ultrathin multilayer capsules in drug delivery

    Directory of Open Access Journals (Sweden)

    Jain Arti

    2007-01-01

    Full Text Available Ultra thin multilayer capsules are attractive and stable systems capable of delivering the bioactives. Ultra thin multilayer capsules consist of polyelectrolytic materials that are formed in the presence of a template. This is achieved through layer-by-layer adsorption of oppositely charged macromolecules on to colloidal particles. Upon extraction, the resulting cavities retain affinity for the bioactives. This review considers the fabrication, of ultra thin multilayer capsules, physiochemical properties and role of ultra thin multilayer capsules within a pharmaceutical remit. Ultrathin multilayer capsules have potential for creating satisfactory drug dosage forms.

  3. Recurrent hypersomnia: a review of 339 cases. : Recurrent hypersomnias

    OpenAIRE

    Billiard, Michel; Jaussent, Isabelle; Dauvilliers, Yves; Besset, Alain

    2011-01-01

    Based on 339 cases this review identifies, quantifies and compares 4 clinical forms of recurrent hypersomnia (1) Kleine-Levin syndrome (KLS) (239 cases), (2) Kleine-Levin syndrome without compulsive eating (KLS WOCE) (54 cases), (3) Menstrual related hypersomnia (MRH) (18 cases) and Recurrent hypersomnia with comorbidity (RHC) (28 cases). A second part of the review considers the main current issues on recurrent hypersomnia: the predisposing factors, including a window on family cases; the pa...

  4. Multilayer Composite Pressure Vessels

    Science.gov (United States)

    DeLay, Tom

    2005-01-01

    A method has been devised to enable the fabrication of lightweight pressure vessels from multilayer composite materials. This method is related to, but not the same as, the method described in gMaking a Metal- Lined Composite-Overwrapped Pressure Vessel h (MFS-31814), NASA Tech Briefs, Vol. 29, No. 3 (March 2005), page 59. The method is flexible in that it poses no major impediment to changes in tank design and is applicable to a wide range of tank sizes. The figure depicts a finished tank fabricated by this method, showing layers added at various stages of the fabrication process. In the first step of the process, a mandrel that defines the size and shape of the interior of the tank is machined from a polyurethane foam or other suitable lightweight tooling material. The mandrel is outfitted with metallic end fittings on a shaft. Each end fitting includes an outer flange that has a small step to accommodate a thin layer of graphite/epoxy or other suitable composite material. The outer surface of the mandrel (but not the fittings) is covered with a suitable release material. The composite material is filament- wound so as to cover the entire surface of the mandrel from the step on one end fitting to the step on the other end fitting. The composite material is then cured in place. The entire workpiece is cut in half in a plane perpendicular to the axis of symmetry at its mid-length point, yielding two composite-material half shells, each containing half of the foam mandrel. The halves of the mandrel are removed from within the composite shells, then the shells are reassembled and bonded together with a belly band of cured composite material. The resulting composite shell becomes a mandrel for the subsequent steps of the fabrication process and remains inside the final tank. The outer surface of the composite shell is covered with a layer of material designed to be impermeable by the pressurized fluid to be contained in the tank. A second step on the outer flange of each end fitting accommodates this layer. Depending on the application, this layer could be, for example, a layer of rubber, a polymer film, or an electrodeposited layer of metal. If the fluid to be contained in the tank is a gas, then the best permeation barrier is electrodeposited metal (typically copper or nickel), which can be effective at a thickness of as little as 0.005 in (.0.13 mm). The electrodeposited metal becomes molecularly bonded to the second step on each metallic end fitting. The permeation-barrier layer is covered with many layers of filament-wound composite material, which could be the same as, or different from, the composite material of the inner shell. Finally, the filament-wound composite material is cured in an ov

  5. Evolution of recurrent fuzzy controllers

    OpenAIRE

    Kavka, Carlos; Roggero, Patricia; Apolloni, Javier

    2004-01-01

    The main advantage of a recurrent architecture is the ability to store information from prior system states. A recurrent fuzzy controller includes hidden fuzzy variables which makes the controller more appropriate to deal with dynamic systems. We are currently investigating the effect of evolution of recurrent fuzzy controllers by applying the FV representation, which provides a set of advantages that can signi catively benefit the quality of the knowledge insertion process.

  6. Local recurrence of laryngeal carcinoma

    OpenAIRE

    Skerleva, D; Stoyanov, S.; Rangachev, J; Assenova, K

    2011-01-01

    Stoma recurrence following total laryngectomy is one of the most severe complications with extremely poor prognosis. Objective: The aim of our study is to analyze the risk factors for stoma recurrence development and to highlight the measures for prevention.Materials and methods: We preformed retrospective study on 530 patients who underwent total laryngectomy at Queen Giovanna Hospital end Ministry of Interior Medical Institute, Sofia for a period of 2 years.Results: Stoma recurrence deve...

  7. Epidemiology of recurrent venous thrombosis

    Directory of Open Access Journals (Sweden)

    D.D. Ribeiro

    2012-01-01

    Full Text Available Venous thrombosis, including deep vein thrombosis and pulmonary embolism, is a common disease that frequently recurs. Recurrence can be prevented by anticoagulants, but this comes at the risk of bleeding. Therefore, assessment of the risk of recurrence is important to balance the risks and benefits of anticoagulant treatment. This review briefly outlines what is currently known about the epidemiology of recurrent venous thrombosis, and focuses in more detail on potential new risk factors for venous recurrence. The general implications of these findings in patient management are discussed.

  8. Abemaciclib in Children With DIPG or Recurrent/Refractory Solid Tumors

    Science.gov (United States)

    2016-04-12

    Diffuse Intrinsic Pontine Glioma; Brain Tumor, Recurrent; Solid Tumor, Recurrent; Neuroblastoma, Recurrent, Refractory; Ewing Sarcoma, Recurrent, Refractory; Rhabdomyosarcoma, Recurrent, Refractory; Osteosarcoma, Recurrent, Refractory; Rhabdoid Tumor, Recurrent, Refractory

  9. Recurrent vulvovaginal candidiasis.

    Science.gov (United States)

    Sobel, Jack D

    2016-01-01

    Recurrent vulvovaginal candidiasis (RVVC) is a common cause of significant morbidity in women in all strata of society affecting millions of women worldwide. Previously, RVVC occurrence was limited by onset of menopause but the widespread use of hormone replacement therapy has extended the at-risk period. Candida albicans remains the dominant species responsible for RVVC, however optimal management of RVVC requires species determination and effective treatment measures are best if species-specific. Considerable progress has been made in understanding risk factors that determine susceptibility to RVVC, particularly genetic factors, as well as new insights into normal vaginal defense immune mechanisms and their aberrations in RVVC. While effective control of RVVC is achievable with the use of fluconazole maintenance suppressive therapy, cure of RVVC remains elusive especially in this era of fluconazole drug resistance. Vaccine development remains a critical challenge and need. PMID:26164695

  10. Thermally induced delamination of multilayers

    DEFF Research Database (Denmark)

    Srensen, Bent F.; Sarraute, S.; Jrgensen, O.; Horsewell, A.

    1998-01-01

    Steady-state delamination of multilayered structures, caused by stresses arising during processing due to thermal expansion mismatch, is analyzed by a fracture mechanics model based on laminate theory. It is found that inserting just a few interlayers with intermediate thermal expansion coefficie......Steady-state delamination of multilayered structures, caused by stresses arising during processing due to thermal expansion mismatch, is analyzed by a fracture mechanics model based on laminate theory. It is found that inserting just a few interlayers with intermediate thermal expansion...... coefficients may be an effective way of reducing the delamination energy release rate. Uneven layer thickness and increasing elastic mismatch are shown to raise the energy release rate. Experimental work confirms important trends of the model....

  11. Constructing multilayers with absorbing materials

    OpenAIRE

    Larruquert, Juan Ignacio; Vidal-Dasilva, M.; Garca-Corts, S.; Fernndez Perea, Mnica; Mndez, Jos A.; Aznrez, Jos Antonio

    2010-01-01

    The strong absorption of materials in the extreme ultraviolet (EUV) above ~50 nm has precluded the development of efficient coatings. The development of novel coatings with improved EUV performance is presented. An extensive research was performed on the search and characterization of materials with moderate absorption, such as various lanthanides. Based on this research, novel multilayers based on Yb, Al, and SiO have been developed with a narrowband performance in the 50-92 nm range. Furthe...

  12. Polyelectrolyte Multilayers in Tissue Engineering

    OpenAIRE

    Detzel, Christopher J.; Larkin, Adam L.; Rajagopalan, Padmavathy

    2011-01-01

    The layer-by-layer assembly of sequentially adsorbed, alternating polyelectrolytes has become increasingly important over the past two decades. The ease and versatility in assembling polyelectrolyte multilayers (PEMs) has resulted in numerous wide ranging applications of these materials. More recently, PEMs are being used in biological applications ranging from biomaterials, tissue engineering, regenerative medicine, and drug delivery. The ability to manipulate the chemical, physical, surface...

  13. Exotic structures on magnetic multilayers

    OpenAIRE

    Kusmartsev, F. V.; Dhillon, H. S.; Crapper, M. D.

    1999-01-01

    To characterize the possible magnetic structures created on magnetic multilayers a model has been formulated and studied. The interlayer inhomogeneous structures found indicate either (i) a regular periodic, (ii) a quasiperiodic change in the magnetization or (iii) spatially chaotic glass states. The magnetic structures created depend mainly on the ratio of the magnetic anisotropy constant to the exchange constant. With the increase of this ratio the periodic structures first transform into t...

  14. Mathematical Formulation of Multilayer Networks

    Science.gov (United States)

    De Domenico, Manlio; Solé-Ribalta, Albert; Cozzo, Emanuele; Kivelä, Mikko; Moreno, Yamir; Porter, Mason A.; Gómez, Sergio; Arenas, Alex

    2013-10-01

    A network representation is useful for describing the structure of a large variety of complex systems. However, most real and engineered systems have multiple subsystems and layers of connectivity, and the data produced by such systems are very rich. Achieving a deep understanding of such systems necessitates generalizing “traditional” network theory, and the newfound deluge of data now makes it possible to test increasingly general frameworks for the study of networks. In particular, although adjacency matrices are useful to describe traditional single-layer networks, such a representation is insufficient for the analysis and description of multiplex and time-dependent networks. One must therefore develop a more general mathematical framework to cope with the challenges posed by multilayer complex systems. In this paper, we introduce a tensorial framework to study multilayer networks, and we discuss the generalization of several important network descriptors and dynamical processes—including degree centrality, clustering coefficients, eigenvector centrality, modularity, von Neumann entropy, and diffusion—for this framework. We examine the impact of different choices in constructing these generalizations, and we illustrate how to obtain known results for the special cases of single-layer and multiplex networks. Our tensorial approach will be helpful for tackling pressing problems in multilayer complex systems, such as inferring who is influencing whom (and by which media) in multichannel social networks and developing routing techniques for multimodal transportation systems.

  15. Ultra-thin multilayer capacitors.

    Energy Technology Data Exchange (ETDEWEB)

    Renk, Timothy Jerome; Monson, Todd C.

    2009-06-01

    The fabrication of ultra-thin lanthanum-doped lead zirconium titanate (PLZT) multilayer ceramic capacitors (MLCCs) using a high-power pulsed ion beam was studied. The deposition experiments were conducted on the RHEPP-1 facility at Sandia National Laboratories. The goal of this work was to increase the energy density of ceramic capacitors through the formation of a multilayer device with excellent materials properties, dielectric constant, and standoff voltage. For successful device construction, there are a number of challenging requirements including achieving correct stoichiometric and crystallographic composition of the deposited PLZT, as well as the creation of a defect free homogenous film. This report details some success in satisfying these requirements, although 900 C temperatures were necessary for PLZT perovskite phase formation. These temperatures were applied to a previously deposited multi-layer film which was then post-annealed to this temperature. The film exhibited mechanical distress attributable to differences in the coefficient of thermal expansion (CTE) of the various layers. This caused significant defects in the deposited films that led to shorts across devices. A follow-on single layer deposition without post-anneal produced smooth layers with good interface behavior, but without the perovskite phase formation. These issues will need to be addressed in order for ion beam deposited MLCCs to become a viable technology. It is possible that future in-situ heating during deposition may address both the CTE issue, and result in lowered processing temperatures, which in turn could raise the probability of successful MLCC formation.

  16. Interfaces in sequence permutated multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Balogh, J; Bujdoso, L; Kaptas, D; Kiss, L F; Kemeny, T; Vincze, I, E-mail: baloghj@szfki.h [Research Institute for Solid State Physics and Optics, 1525 Budapest PO Box 49 (Hungary)

    2010-03-01

    Sequence permutation of three building block multilayers was recently suggested as a new approach in studying bottom and top interfaces formed of a given layer with either of the other two elements. It was applied to Fe-B-Ag multilayers with 5 nm Ag layers separating the Fe and the B layers. Now we examine the dependence of the chemical mixing and the consequent amorphous phase formation on the nominal thickness of the Ag layers in [2 nm B / 2nm Fe / x nm Ag]{sub 4}, 0.2{<=}x{<=}10, multilayers. The ratio of the non-alloyed Fe layer and the amorphous Fe-B interface compound changes only below x=5 nm. It is attributed to discontinuities of the Ag layer due to its three dimensional island growth over the bcc-Fe layer. The results obtained on the variation of the hyperfine field distribution of the amorhous Fe-B layers also confirm that the top interfaces of Fe with B are more B-rich than the bottom ones.

  17. Shortest recurrence periods of novae

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Mariko [Department of Astronomy, Keio University, Hiyoshi, Yokohama 223-8521 (Japan); Saio, Hideyuki [Astronomical Institute, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan); Hachisu, Izumi [Department of Earth Science and Astronomy, College of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan); Nomoto, Ken' ichi, E-mail: mariko@educ.cc.keio.ac.jp [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

    2014-10-01

    Stimulated by the recent discovery of the 1 yr recurrence period nova M31N 2008-12a, we examined the shortest recurrence periods of hydrogen shell flashes on mass-accreting white dwarfs (WDs). We discuss the mechanism that yields a finite minimum recurrence period for a given WD mass. Calculating the unstable flashes for various WD masses and mass accretion rates, we identified a shortest recurrence period of about two months for a non-rotating 1.38 M {sub ?} WD with a mass accretion rate of 3.6 10{sup 7} M {sub ?} yr{sup 1}. A 1 yr recurrence period is realized for very massive (? 1.3 M {sub ?}) WDs with very high accretion rates (? 1.5 10{sup 7} M {sub ?} yr{sup 1}). We revised our stability limit of hydrogen shell burning, which will be useful for binary evolution calculations toward Type Ia supernovae.

  18. Multilayer Analysis and Visualization of Networks

    CERN Document Server

    De Domenico, Manlio; Arenas, Alex

    2014-01-01

    Multilayer relationships among and information about biological entities must be accompanied by the means to analyze, visualize, and obtain insights from such data. We report a methodology and a collection of algorithms for the analysis of multilayer networks in our new open-source software (muxViz). We demonstrate the ability of muxViz to analyze and interactively visualize multilayer data using empirical genetic and neuronal networks.

  19. BESSY Bragg-Fresnel multilayer beam monitors

    International Nuclear Information System (INIS)

    X-ray optical systems based on Bragg-Fresnel multilayer components imaging an electron beam in a storage ring with microm resolution are presented. Design concepts are compared to alternative methods, and the aberrations and limits of Bragg-Fresnel multilayer optics are discussed. Experimental results of imaging the BESSY 1 source with sub 10 microm resolution are presented and the development of a compact Bragg-Fresnel multilayer telescope as a BESSY 2 standard beam monitor is described

  20. Electrical conductivity of collapsed multilayer graphene tubes

    OpenAIRE

    De Mendoza, D

    2011-01-01

    Synthesis of multilayer graphene on copper wires by a chemical vapor deposition method is reported. After copper etching, the multilayer tube collapses forming stripes of graphitic films, their electrical conductance as a function of temperature indicate a semiconductor-like behavior. Using the multilayer graphene stripes, a cross junction is built and owing to its electrical behavior we propose that a tunneling process exists in the device.

  1. Vacuum multilayer lamination of printed wiring boards

    Science.gov (United States)

    Wilkus, J. W.

    1992-11-01

    This experiment investigates vacuum multilayer lamination of rigid/flex, epoxy glass, polyimide glass, and polyimide quartz printed wiring boards. The effectiveness of the vacuum in removing entrapped air during the lamination cycle is demonstrated. The results of the experiment have also shown that vacuum lamination of epoxy glass multilayers improves the delamination resistance. Thus, epoxy glass multilayers that have been vacuum laminated will be able to withstand soldering temperatures longer without delaminating. Also, the experiment shows that vacuum multilayer lamination does not significantly change thickness, layer-to-layer registration, glass transition temperature, dielectric spacing between conductors, electrical resistance following thermal shock test, and other critical printed wiring board properties.

  2. Plasma engineering of multilayered carbon coatings

    International Nuclear Information System (INIS)

    Full text: Thin film coatings consisting of alternating layers of different materials or phases (multilayers) with structural features in the nanometer scale can exhibit exceptional mechanical properties. For demanding applications such as cutting tools and biomedical devices, this new and novel method for producing coatings may prove to be superior compared to traditional single-layer coatings. However, the relationship between microstructure and properties in multilayers is not well understood. We investigate the possibility of producing multilayers consisting of different forms of amorphous carbon. We show that these types of multilayered structures can be synthesised using plasma deposition and processing. Copyright (2005) Australian Institute of Physics

  3. STDP in recurrent neuronal networks

    Directory of Open Access Journals (Sweden)

    Matthieu Gilson

    2010-09-01

    Full Text Available Recent results about spike-timing-dependent plasticity (STDP in recurrently connected neurons are reviewed, with a focus on the relationship between the weight dynamics and the emergence of network structure. In particular, the evolution of synaptic weights in the two cases of incoming connections for a single neuron and recurrent connections are compared and contrasted. A theoretical framework is used that is based upon Poisson neurons with a temporally inhomogeneous firing rate and the asymptotic distribution of weights generated by the learning dynamics. Different network configurations examined in recent studies are discussed and an overview of the current understanding of STDP in recurrently connected neuronal networks is presented.

  4. Giant recurrent retroperitoneal liposarcoma presenting as a recurrent inguinal hernia

    OpenAIRE

    Bhandarwar, Ajay H; Bakhshi, Girish D.; Borisa, Ashok D.; Shenoy, Sachin S.; Kori, Channabasappa G.; Sameer Vora

    2011-01-01

    Retroperitoneal liposarcoma presenting as an inguinal hernia is a rare entity. We present the first case of Giant recurrent liposarcoma presenting as a recurrent inguinal hernia in a 40-year-old male. Physical examination showed an irreducible lump in the right inguinal region and a scar in the right lumbar and right inguinal region. Computed tomography (CT) scan of abdomen revealed it to be a retro peritoneal mass extending into the right inguinal region along and involving the cord structur...

  5. Multi-Layer Traffic Steering

    DEFF Research Database (Denmark)

    Fotiadis, Panagiotis; Polignano, Michele; Gimenez, Lucas Chavarria; Viering, Ingo; Sartori, Cinzia; Lobinger, Andreas; Pedersen, Klaus I.

    2013-01-01

    This paper investigates the potentials of traffic steering in the Radio Resource Control (RRC) Idle state by evaluating the Absolute Priorities (AP) framework in a multilayer Long Term Evolution (LTE) macrocell scenario. Frequency priorities are broadcast on the system information and RRC Idle...... users can be steered towards higher priority carriers whenever coverage allows it. However, such an approach may overload the prioritized layers. For that purpose, an enhanced scheme is proposed, where priorities are adjusted on a user basis and are provided to the terminal via the connection release...

  6. Recurrent networks for wave forecasting

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Prabaharan, N.

    , merchant vessel routing, nearshore construction, etc. more efficiently and safely. This paper presents an application of the Artificial Neural Network, namely Backpropagation Recurrent Neural Network (BRNN) with rprop update algorithm for wave forecasting...

  7. Opioids and breast cancer recurrence

    DEFF Research Database (Denmark)

    Cronin-Fenton, Deirdre P; Heide-Jørgensen, Uffe; Ahern, Thomas P; Lash, Timothy L; Christiansen, Peer M; Ejlertsen, Bent; Sjøgren, Per; Kehlet, Henrik; Sørensen, Henrik T.

    2015-01-01

    BACKGROUND: Opioids may alter immune function, thereby potentially affecting cancer recurrence. The authors investigated the association between postdiagnosis opioid use and breast cancer recurrence. METHODS: Patients with incident, early stage breast cancer who were diagnosed during 1996 through...... 2008 in Denmark were identified from the Danish Breast Cancer Cooperative Group Registry. Opioid prescriptions were ascertained from the Danish National Prescription Registry. Follow-up began on the date of primary surgery for breast cancer and continued until breast cancer recurrence, death......, emigration, 10 years, or July 31, 2013, whichever occurred first. Cox regression models were used to compute hazard ratios and 95% confidence intervals associating breast cancer recurrence with opioid prescription use overall and by opioid type and strength, immunosuppressive effect, chronic use (≥6 months...

  8. Primary breast lymphoma; disease recurrence

    Directory of Open Access Journals (Sweden)

    Hüseyin KADIOĞLU

    2012-01-01

    Full Text Available Primary breast lymphoma (PBL accounts 0.4-0.5% of all breast cancers. The aim is to present the patient diagnosed with recurrency of primary breast lymphoma treated six year ago without radiotherapy. A 63-years-old woman patient admitted to our hospital with a palpabl mass in her left breast. Six years ago she was treated with chemoterapy after local excision for primary left breast lymphoma. Imaging modalities showed multiple lesion in breast and confirmed with biopsy. Pathologic results were similar with first one and the case was accepted as PBL recurrence. Multipl metastases has been determined with staging modalities. Patient started to chemotherapy treatment. PBL is a rare cancer of breast and there is no consensus at the treatment of disease. In the literature addition of radiotherapy to the treatment prevents local recurrence. There were occured recurrence without radiotherapy, mimicked that radiotherapy is an essential modality in PBL treatment.

  9. Opioids and breast cancer recurrence

    DEFF Research Database (Denmark)

    Cronin-Fenton, Deirdre P; Heide-Jrgensen, Uffe; Ahern, Thomas P; Lash, Timothy L; Christiansen, Peer M; Ejlertsen, Bent; Sjgren, Per; Kehlet, Henrik; Srensen, Henrik T

    2015-01-01

    BACKGROUND: Opioids may alter immune function, thereby potentially affecting cancer recurrence. The authors investigated the association between postdiagnosis opioid use and breast cancer recurrence. METHODS: Patients with incident, early stage breast cancer who were diagnosed during 1996 through...... 2008 in Denmark were identified from the Danish Breast Cancer Cooperative Group Registry. Opioid prescriptions were ascertained from the Danish National Prescription Registry. Follow-up began on the date of primary surgery for breast cancer and continued until breast cancer recurrence, death......, emigration, 10 years, or July 31, 2013, whichever occurred first. Cox regression models were used to compute hazard ratios and 95% confidence intervals associating breast cancer recurrence with opioid prescription use overall and by opioid type and strength, immunosuppressive effect, chronic use (?6 months...

  10. Recurrent ameloblastoma of the mandible

    OpenAIRE

    Joshi, C P; Vyas, K. C.; Deedwania, Seema; Jain, Sanjeev; Mangal, M. M.

    1999-01-01

    Ameloblastoma is an agressive locally recurring neoplasm of odentogenic epithelium. Here we describe a case of mandibular ameloblastoma with 12 yrs. history of local recurrences followed with history of excision twice (10 yrs. and 7 years back).

  11. Multi-Layer E-Textile Circuits

    Science.gov (United States)

    Dunne, Lucy E.; Bibeau, Kaila; Mulligan, Lucie; Frith, Ashton; Simon, Cory

    2012-01-01

    Stitched e-textile circuits facilitate wearable, flexible, comfortable wearable technology. However, while stitched methods of e-textile circuits are common, multi-layer circuit creation remains a challenge. Here, we present methods of stitched multi-layer circuit creation using accessible tools and techniques.

  12. Multilayer Graphene for Waveguide Terahertz Modulator

    DEFF Research Database (Denmark)

    Khromova, I.; Andryieuski, Andrei; Lavrinenko, Andrei

    2014-01-01

    We study terahertz to infrared electromagnetic properties of multilayer graphene/dielectric artificial medium and present a novel concept of terahertz modulation at midinfrared wavelengths. This approach allows the realization of high-speed electrically controllable terahertz modulators based on...... hollow waveguide sections filled with multilayer graphene....

  13. Annealing of Co/Ag multilayers

    Science.gov (United States)

    Tosin, G.; Schelp, L. F.; Carara, M.; Schmidt, J. E.; Gomes, A. A.; Baibich, M. N.

    1993-03-01

    We have measured the magnetoresistance and magnetic properties of annealed Co/Ag multilayers. The results show an increase of the magnetoresistance associated to lower interface roughness for these immiscible elements. Higher temperature anneals lead to destruction of the multilayer, but still showing giant magnetoresistance for the composite formed.

  14. Learning Compact Recurrent Neural Networks

    OpenAIRE

    Lu, Zhiyun; Sindhwani, Vikas; Sainath, Tara N.

    2016-01-01

    Recurrent neural networks (RNNs), including long short-term memory (LSTM) RNNs, have produced state-of-the-art results on a variety of speech recognition tasks. However, these models are often too large in size for deployment on mobile devices with memory and latency constraints. In this work, we study mechanisms for learning compact RNNs and LSTMs via low-rank factorizations and parameter sharing schemes. Our goal is to investigate redundancies in recurrent architectures where compression ca...

  15. Deep Gate Recurrent Neural Network

    OpenAIRE

    Gao, Yuan; Glowacka, Dorota

    2016-01-01

    This paper introduces two recurrent neural network structures called Simple Gated Unit (SGU) and Deep Simple Gated Unit (DSGU), which are general structures for learning long term dependencies. Compared to traditional Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU), both structures require fewer parameters and less computation time in sequence classification tasks. Unlike GRU and LSTM, which require more than one gates to control information flow in the network, SGU and DSGU only...

  16. Recurrence Quantification of Fractal Structures

    OpenAIRE

    Webber, Charles L.

    2012-01-01

    By definition, fractal structures possess recurrent patterns. At different levels repeating patterns can be visualized at higher magnifications. The purpose of this chapter is threefold. First, general characteristics of dynamical systems are addressed from a theoretical mathematical perspective. Second, qualitative and quantitative recurrence analyses are reviewed in brief, but the reader is directed to other sources for explicit details. Third, example mathematical systems that generate str...

  17. Treatment of Severe Recurrent Clubfoot.

    Science.gov (United States)

    Radler, Christof; Mindler, Gabriel T

    2015-12-01

    Understanding the pathoanatomy of severe recurrent clubfoot and its implication on treatment options is important for the successful treatment. A comprehensive clinical evaluation of the different components helps in selecting procedures. Individual needs and social and psychological factors influencing treatment and the impact of treatment on the child have to be considered. With increasing dissemination and improved understanding of the Ponseti method, a further decrease in the frequency of severe recurrent clubfoot can be hoped for and expected. PMID:26589079

  18. Recurrent Rhabdoid Meningioma: Case Report

    OpenAIRE

    Jansen, Jeroen C; Turner, Jenny; Sheehy, John; Fagan, Paul A.

    2003-01-01

    Most meningiomas are slow–growing tumors that do not rapidly recur after subtotal removal. After subtotal resection of a meningioma a 47–year–old woman developed a large extracranial recurrence 1 year later. The recurrence was resected successfully. On histological examination the typical characteristics of a meningioma were absent. Based on immunohistological and ultrastructural studies, the tumor was classified as a grade III meningioma of the newly recognized rhabdoid subtype.

  19. Recurrence for random dynamical systems

    OpenAIRE

    Marie, Philippe; Rousseau, Jerome

    2011-01-01

    This paper is a first step in the study of the recurrence behavior in random dynamical systems and randomly perturbed dynamical systems. In particular we define a concept of quenched and annealed return times for systems generated by the composition of random maps. We moreover prove that for super-polynomially mixing systems, the random recurrence rate is equal to the local dimension of the stationary measure.

  20. Multilayer Nanoporous Graphene Membranes for Water Desalination.

    Science.gov (United States)

    Cohen-Tanugi, David; Lin, Li-Chiang; Grossman, Jeffrey C

    2016-02-10

    While single-layer nanoporous graphene (NPG) has shown promise as a reverse osmosis (RO) desalination membrane, multilayer graphene membranes can be synthesized more economically than the single-layer material. In this work, we build upon the knowledge gained to date toward single-layer graphene to explore how multilayer NPG might serve as a RO membrane in water desalination using classical molecular dynamic simulations. We show that, while multilayer NPG exhibits similarly promising desalination properties to single-layer membranes, their separation performance can be designed by manipulating various configurational variables in the multilayer case. This work establishes an atomic-level understanding of the effects of additional NPG layers, layer separation, and pore alignment on desalination performance, providing useful guidelines for the design of multilayer NPG membranes. PMID:26806020

  1. Figure correction of multilayer coated optics

    Science.gov (United States)

    Chapman; Henry N. , Taylor; John S.

    2010-02-16

    A process is provided for producing near-perfect optical surfaces, for EUV and soft-x-ray optics. The method involves polishing or otherwise figuring the multilayer coating that has been deposited on an optical substrate, in order to correct for errors in the figure of the substrate and coating. A method such as ion-beam milling is used to remove material from the multilayer coating by an amount that varies in a specified way across the substrate. The phase of the EUV light that is reflected from the multilayer will be affected by the amount of multilayer material removed, but this effect will be reduced by a factor of 1-n as compared with height variations of the substrate, where n is the average refractive index of the multilayer.

  2. Antigen expression on recurrent meningioma cells

    International Nuclear Information System (INIS)

    Meningiomas are intracranial brain tumours that frequently recur. Recurrence rates up to 20% in 20 years for benign meningiomas, up to 80% for atypical meningiomas and up to 100% for malignant meningiomas, have been reported. The most important prognostic factors for meningioma recurrence are meningioma grade, meningioma invasiveness and radicality of neurosurgical resection. The aim of our study was to evaluate the differences in antigenic expression on the surface of meningioma cells between recurrent and non-recurrent meningiomas. 19 recurrent meningiomas and 35 non-recurrent meningiomas were compared regarding the expression of MIB-1 antigen, progesterone receptors, cathepsin B and cathepsin L, using immunohistochemistry. MIB-1 antigen expression was higher in the recurrent meningioma group (p=0.001). No difference in progesterone receptor status between recurrent and non-recurrent meningiomas was confirmed. Immunohistochemical intensity scores for cathepsin B (p= 0.007) and cathepsin L (p<0.001) were both higher in the recurrent than in the non-recurrent meningioma group. MIB-1 antigen expression is higher in recurrent compared to non-recurrent meningiomas. There is no difference in expression of progesterone receptors between recurrent and non-recurrent meningiomas. Cathepsins B and L are expressed more in recurrent meningiomas

  3. On uniform recurrence of a direct product

    OpenAIRE

    Salimov, Pavel Vadimovich

    2010-01-01

    The direct product of two words is a naturally defined word on the alphabet of pairs of symbols. An infinite word is uniformly recurrent if each its subword occurs in it with bounded gaps. An infinite word is strongly recurrent if the direct product of it with each uniformly recurrent word is also uniformly recurrent. We prove that fixed points of the expanding binary symmetric morphisms are strongly recurrent. In particular, such is the Thue-Morse word.

  4. Recent advances in etched multilayer X-ray optics

    OpenAIRE

    Andr, J; Sammar, A.; Bac, S.; Ouahabi, M.; Idir, M.; Soulli, G.; Barchewitz, R.

    1994-01-01

    We present the recent advances achieved in the Laboratoire de Chimie Physique of Universit Paris6, in the field of the soft X-ray etched multilayer optics. Modellings and characterizations are given for the laminar multilayer amplitude gratings, the highly resolutive X-ray multilayer monochromators, the X-ray polychromators and the Bragg-Fresnel multilayer linear lenses.?

  5. Solder fused interconnections in multilayer circuits

    Energy Technology Data Exchange (ETDEWEB)

    Voida, G.

    1977-02-01

    A new solder fusion process has been developed for production of multi-layer cables and multilayer printed wiring boards. The multilayer process consists of three steps: (1) the photo-etching fabrication of the basic flexcircuit, (2) the lamination bonding of several flexcircuit layers together, and (3) solder fusion interjoining of the exposed lands to provide electrical continuity. Solder fusion is the unique feature of the process. In the solder fusion process the multilayer assembly is never in contact with highly reactive chemicals which, if entrapped, can lead to corrosion and dielectric breakdown of the assembly. Accurate layer to layer registration can be accomplished with the solder fusion process. A multilayer assembly produced by solder fusion can be shaped into three-dimensional configurations. The repeatable electrical continuity of solder fused interconnections in multilayer assemblies has been confirmed by microhm resistance testing. The solder fused multilayer assembly can be used very advantageously in highly sophisticated instruments and apparatus where portability, weight, bulk, environmental stability, and high reliability are critical requirements.

  6. RECURRENT NOVAE IN M31

    Energy Technology Data Exchange (ETDEWEB)

    Shafter, A. W. [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); Henze, M. [European Space Astronomy Centre, P.O. Box 78, E-28692 Villanueva de la Cañada, Madrid (Spain); Rector, T. A. [Department of Physics and Astronomy, University of Alaska Anchorage, 3211 Providence Dr., Anchorage, AK 99508 (United States); Schweizer, F. [Carnegie Observatories, 813 Santa Barbara St., Pasadena, CA 91101 (United States); Hornoch, K. [Astronomical Institute, Academy of Sciences, CZ-251 65 Ondřejov (Czech Republic); Orio, M. [Astronomical Observatory of Padova (INAF), I-35122 Padova (Italy); Pietsch, W. [Max Planck Institute for Extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., D-85741, Garching (Germany); Darnley, M. J.; Williams, S. C.; Bode, M. F. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool L3 5RF (United Kingdom); Bryan, J., E-mail: aws@nova.sdsu.edu [McDonald Observatory, Austin, TX 78712 (United States)

    2015-02-01

    The reported positions of 964 suspected nova eruptions in M31 recorded through the end of calendar year 2013 have been compared in order to identify recurrent nova (RN) candidates. To pass the initial screen and qualify as a RN candidate, two or more eruptions were required to be coincident within 0.′1, although this criterion was relaxed to 0.′15 for novae discovered on early photographic patrols. A total of 118 eruptions from 51 potential RN systems satisfied the screening criterion. To determine what fraction of these novae are indeed recurrent, the original plates and published images of the relevant eruptions have been carefully compared. This procedure has resulted in the elimination of 27 of the 51 progenitor candidates (61 eruptions) from further consideration as RNe, with another 8 systems (17 eruptions) deemed unlikely to be recurrent. Of the remaining 16 systems, 12 candidates (32 eruptions) were judged to be RNe, with an additional 4 systems (8 eruptions) being possibly recurrent. It is estimated that ∼4% of the nova eruptions seen in M31 over the past century are associated with RNe. A Monte Carlo analysis shows that the discovery efficiency for RNe may be as low as 10% that for novae in general, suggesting that as many as one in three nova eruptions observed in M31 arise from progenitor systems having recurrence times ≲100 yr. For plausible system parameters, it appears unlikely that RNe can provide a significant channel for the production of Type Ia supernovae.

  7. An Undecidable Nested Recurrence Relation

    CERN Document Server

    Celaya, Marcel

    2012-01-01

    Roughly speaking, a recurrence relation is nested if it contains a subexpression of the form ... A(...A(...)...). Many nested recurrence relations occur in the literature, and determining their behavior seems to be quite difficult and highly dependent on their initial conditions. A nested recurrence relation A(n) is said to be undecidable if the following problem is undecidable: given a finite set of initial conditions for A(n), is the recurrence relation calculable? Here calculable means that for every n >= 0, either A(n) is an initial condition or the calculation of A(n) involves only invocations of A on arguments in {0,1,...,n-1}. We show that the recurrence relation A(n) = A(n-4-A(A(n-4)))+4A(A(n-4)) +A(2A(n-4-A(n-2))+A(n-2)). is undecidable by showing how it can be used, together with carefully chosen initial conditions, to simulate Post 2-tag systems, a known Turing complete problem.

  8. Magnetic quantization in multilayer graphenes

    CERN Document Server

    Lin, Chiun-Yan; Ou, Yih-Jon; Chiu, Yu-Huang; Lin, Ming-Fa

    2015-01-01

    Essential properties of multilayer graphenes are diversified by the number of layers and the stacking configurations. For an $N$-layer system, Landau levels are divided into $N$ groups, with each identified by a dominant sublattice associated with the stacking configuration. We focus on the main characteristics of Landau levels, including the degeneracy, wave functions, quantum numbers, onset energies, field-dependent energy spectra, semiconductor-metal transitions, and crossing patterns, which are reflected in the magneto-optical spectroscopy, scanning tunneling spectroscopy, and quantum transport experiments. The Landau levels in AA-stacked graphene are responsible for multiple Dirac cones, while in AB-stacked graphene the Dirac properties depend on the number of graphene layers, and in ABC-stacked graphene the low-lying levels are related to surface states. The Landau-level mixing leads to anticrossings patterns in energy spectra, which are seen for intergroup Landau levels in AB-stacked graphene, while in...

  9. Planar Multilayer Circuit Quantum Electrodynamics

    Science.gov (United States)

    Minev, Z. K.; Serniak, K.; Pop, I. M.; Leghtas, Z.; Sliwa, K.; Hatridge, M.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

    2016-04-01

    Experimental quantum information processing with superconducting circuits is rapidly advancing, driven by innovation in two classes of devices, one involving planar microfabricated (2D) resonators, and the other involving machined three-dimensional (3D) cavities. We demonstrate that circuit quantum electrodynamics can be implemented in a multilayer superconducting structure that combines 2D and 3D advantages. We employ standard microfabrication techniques to pattern each layer, and rely on a vacuum gap between the layers to store the electromagnetic energy. Planar qubits are lithographically defined as an aperture in a conducting boundary of the resonators. We demonstrate the aperture concept by implementing an integrated, two-cavity-mode, one-transmon-qubit system.

  10. Phase stability in metallic multilayers

    Science.gov (United States)

    Genc, Arda

    As the thin film materials used in electronic and optical applications continue to decrease in thickness to the nano-scales, marked changes in functional properties are expected to occur due to changes in crystal structure of these materials. Therefore, such multilayer systems have been of considerable interest due to the ability to control properties by engineering the structure of materials at these scales. The new characterization tools allow direct imaging and analysis of such materials in order to link the performance variations with the crystal structure variations. Transmission Electron Microscopy (TEM) has been often the technique of choice in characterization of nanomaterials enabling not only imaging the structure of the material but also chemically probing of the composition changes at a high spatial resolution. The ultimate resolution achievable in the electron microscope is a product of both microscope and the specimen and the simultaneous effect of each defines the quality and quantity of the information transferred through the microscope. In this sense, the common ion-beam assisted TEM sample preparation techniques have been deeply recognized as being surface damaging at high ion milling energies (>5kV) thus limiting the information transfer in the microscope. For the first time, a low energy (aberration of the electromagnetic lenses. Recently this problem has been solved by the correction of the spherical aberration of the microscope using a set of non-round lenses and consequently the information limit in an aberration corrected microscope (<0.1nm) has been pushed beyond an uncorrected microscope (˜0.13nm). In 2007, such a corrector system in the probe-forming lens of a Scanning TEM microscope was successfully installed at The Ohio State University. The preliminary results from this microscope were presented in the content of this work where we have studied the microscope and performed first hand experiments. Finally we have addressed the phase stability in Cu/Nb and Ti/Nb nanoscale metallic multilayers by extensive use of these advance characterization techniques and tools. At reduced layer thickness (<2nm) the change in fcc to bcc phase in Cu and hcp to bcc phase in Ti were experimentally confirmed using X-ray diffraction electron diffraction and electron imaging techniques along the plan-view and cross-section directions. These structural transformations were often referred to as being thermodynamic in nature and a classical thermodynamical model explains and predicts the formation of such pseudomorphic phases through the competition of volumetric and interfacial free energy variables. We have investigated both the structural and chemical changes in the Cu/Nb and Ti/Nb nanoscale metallic mutilayers as a function of length scale in order to understand and predict the phase stability. The important constituents: volumetric free energy and interfacial energy changes were experimentally derived considering the chemistry and structure of the multilayers and competition between these thermodynamic terms well explains the observed structural changes in nanoscale metallic multilayers.

  11. Centrality in Interconnected Multilayer Networks

    CERN Document Server

    De Domenico, Manlio; Omodei, Elisa; Gómez, Sergio; Arenas, Alex

    2013-01-01

    Real-world complex systems exhibit multiple levels of relationships. In many cases, they require to be modeled by interconnected multilayer networks, characterizing interactions on several levels simultaneously. It is of crucial importance in many fields, from economics to biology, from urban planning to social sciences, to identify the most (or the less) influent nodes in a network. However, defining the centrality of actors in an interconnected structure is not trivial. In this paper, we capitalize on the tensorial formalism, recently proposed to characterize and investigate this kind of complex topologies, to show how several centrality measures -- well-known in the case of standard ("monoplex") networks -- can be extended naturally to the realm of interconnected multiplexes. We consider diagnostics widely used in different fields, e.g., computer science, biology, communication and social sciences, to cite only some of them. We show, both theoretically and numerically, that using the weighted monoplex obta...

  12. The physics of multilayer networks

    CERN Document Server

    De Domenico, Manlio; Porter, Mason A; Arenas, Alex

    2016-01-01

    The study of networks plays a crucial role in investigating the structure, dynamics, and function of a wide variety of complex systems in myriad disciplines. Despite the success of traditional network analysis, standard networks provide a limited representation of these systems, which often includes different types of relationships (i.e., "multiplexity") among their constituent components and/or multiple interacting subsystems. Such structural complexity has a significant effect on both dynamics and function. Throwing away or aggregating available structural information can generate misleading results and provide a major obstacle towards attempts to understand the system under analysis. The recent "multilayer' approach for modeling networked systems explicitly allows the incorporation of multiplexity and other features of realistic networked systems. On one hand, it allows one to couple different structural relationships by encoding them in a convenient mathematical object. On the other hand, it also allows o...

  13. Near field imaging from multilayer lens.

    Science.gov (United States)

    Li, Guixin; Li, Jensen; Tam, H L; Chan, C T; Cheah, K W

    2011-12-01

    Multilayer superlens has been reported that it had advantages over the single metal layer superlens. In this work, single silver layer and Ag-SiO2 multilayer superlens devices working at wavelength of 365 nm were fabricated using standard photolithography method. Grating objects with line/space (190 nm/190 nm) resolution could be resolved through both kinds of lens structures with working distance up to 128 nm. However, Ag-SiO2 multilayer lens shows higher transmittance and image contrast than the single silver layer device, the experimental result proves the theoretical calculation. PMID:22408982

  14. Multilayer networks: metrics and spectral properties

    CERN Document Server

    Cozzo, Emanuele; Rodrigues, Francisco A; Moreno, Yamir

    2015-01-01

    Multilayer networks represent systems in which there are several topological levels each one representing one kind of interaction or interdependency between the systems' elements. These networks have attracted a lot of attention recently because their study allows considering different dynamical modes concurrently. Here, we revise the main concepts and tools developed up to date. Specifically, we focus on several metrics for multilayer network characterization as well as on the spectral properties of the system, which ultimately enable for the dynamical characterization of several critical phenomena. The theoretical framework is also applied for description of real-world multilayer systems.

  15. BESSY Bragg-Fresnel multilayer beam monitors

    International Nuclear Information System (INIS)

    X-ray optical systems based on Bragg-Fresnel multilayer components imaging an electron beam in a storage ring with μm resolution are presented. Design concepts are compared to alternative methods, and the aberrations and limits of Bragg-Fresnel multilayer optics are discussed. Experimental results of imaging the BESSY I source with sub-10-μm resolution are presented, and the development of a compact Bragg-Fresnel multilayer telescope as a BESSY II standard beam monitor is described. copyright 1996 American Institute of Physics

  16. Magnetic properties of Ni/Pt multilayers

    International Nuclear Information System (INIS)

    We have grown Ni/Pt multilayers with Pt buffer layer, by evaporation under UHV conditions on glass substrates maintained at 300 K. The magnetic properties of Ni/Pt multilayers are examined as a function of Ni layer thickness t Ni. The temperature dependence of the spontaneous magnetization M(T) is well described by a T 3/2 law in all multilayers. A spin-wave theory has been used to explain the temperature dependence of the magnetization and the approximate values for the bulk exchange interaction J b, surface exchange interaction J S and the interlayer coupling strength J I for various Ni layer thicknesses have been obtained

  17. Tunable optical properties of multilayers black phosphorus

    CERN Document Server

    Low, Tony; Carvalho, A; Jiang, Yongjin; Wang, Han; Xia, Fengnian; Neto, A H Castro

    2014-01-01

    We calculated the optical conductivity tensor of multilayers black phosphorus using the Kubo formula within an effective low-energy Hamiltonian. The optical absorption spectra of multilayers black phosphorus are shown to vary sensitively with thickness, doping, and light polarization. In conjunction with experimental spectra obtained from infrared absorption spectroscopy, we discuss the role of interband coupling and disorder on the observed anisotropic absorption spectra. Multilayers black phosphorus might offer attractive alternatives to narrow gap compound semiconductors for optoelectronics across mid- to near-infrared frequencies.

  18. Thermionic cooling in semiconductor multilayers

    International Nuclear Information System (INIS)

    Full text: A solid-state refrigerator in which electrons transport heat has advantages over the conventional vapour-cycle, compressor-based domestic refrigerator since it has no moving parts, it is low-maintenance, silent, vibration-free and does not require the use of refrigerant gases. The usual approach to making an all-electrical refrigerator is by thermoelectric refrigeration. After a period of intense research in the 1950s and 60s it was realised that the efficiency of thermoelectric devices was less than, and unlikely to exceed, that of conventional compressor units. While thermoelectric cooling has found specialised applications in cases where reliability, compactness and weight are important considerations, it does not appear that thermo-electrics will ever successfully compete in the domestic market, in spite of recent advances in the design and fabrication of thermoelectric materials. A new approach to an all-electric refrigerator is to employ thermionic emission over potential barriers. A key difference between a thermoelectric device and a thermionic device is that in the former the electrons are scattered in their motion and in the latter they are not. Thus thermionic cooling, in principle, can be much more efficient than thermoelectric cooling. A radical new realisation of the thermionic refrigerator was suggested recently in which a multilayer semiconductor structure would be used. We discuss the optimisation of such a multilayer semiconductor cooling system by considering (1) electron-phonon interactions in the barriers and electrodes; (2) the detailed treatment of thermal conductivity; (3) an exact numerical solution of the heat and energy currents (in contrast to the previous approximate analytic solutions); (4) the effect of varying layer thickness across the device; and (5) the effect of varying current density across the device

  19. Oncolytic HSV-1716 in Treating Younger Patients With Refractory or Recurrent High Grade Glioma That Can Be Removed By Surgery

    Science.gov (United States)

    2015-10-19

    Recurrent Childhood Anaplastic Astrocytoma; Recurrent Childhood Anaplastic Oligoastrocytoma; Recurrent Childhood Anaplastic Oligodendroglioma; Recurrent Childhood Giant Cell Glioblastoma; Recurrent Childhood Glioblastoma; Recurrent Childhood Gliomatosis Cerebri; Recurrent Childhood Gliosarcoma

  20. Recurrent IVF failure: other factors.

    Science.gov (United States)

    Penzias, Alan S

    2012-05-01

    IVF failure is a problem for a couple in the singular but can be a tragedy in the plural. Recurrent IVF failure has multiple known causes but many which are not routinely considered as part of the posttreatment analysis. The reason is there are several causes associated with lifestyle and other causes related to pre-existing conditions that have only a tenuous or no apparent connection to fertility. This article examines the impact of obesity, cigarette smoke, uterine anatomy, body mass index, thyroid dysfunction, immune factors, the hereditary and acquired thrombophilias, and embryo transfer technique on recurrent IVF failure. PMID:22464759

  1. Radiotherapy for recurrent breast cancer

    International Nuclear Information System (INIS)

    Clinico-radiobiological characteristics of radiotherapy for relapsed breast cancer were studied. Adequate choice of tissue mass to be exposed appeared much more important than any change in focal dose within 50-80 Gy, to achieve higher frequency of locoregional therapeutic effect. However, recurrent tumors more than 3 large lower radiosensitivity involving a sharp rise in the likelihood of dissemination. Radiotherapy for primary tumor did not affect the radiosensitivity of recurrent malignancies but slowed down the rate of its growth. Also, it might promote the dissemination acceleration

  2. Multilayer Kohonen network and its separability analysis

    Science.gov (United States)

    Liu, Chao-yuan; Li, Jie-Gu

    1995-04-01

    This paper presents a model of a multilayer Kohonen network. Because of obeying the winner- take-all learning rule and projecting high dimensional patterns into one or two dimensional space, the conventional Kohonen network has many limitations in its applications, such as pattern separability limitation and open ended limitation. Taking advantage of the innovation for learning method and its multilayer structure, the multilayer Kohonen network has the performance of nonlinear pattern partition. Owing to labeling pattern clusters with appropriate category names or numbers only, the network is an open ended system, so it is far more powerful than the conventional Kohonen network. The mechanism of the multilayer Kohonen network is explained in detail, and its nonlinear pattern separability is analyzed theoretically. As a result of an experiment made by two layer Kohonen network, a set of human head contour figures assigned into diverse by categories is shown.

  3. Irradiated multilayer film for primal meat packaging

    International Nuclear Information System (INIS)

    This patent deals with a heat-shrinkable, multilayer film suitable for use in fabricating bags for packaging primal and sub-primal meat cuts and processed meats. The multilayer film has a first outer layer of a first ethylene-vinyl acetate copolymer, a core layer of a polyvinylidene chloride-vinyl chloride copolymer containing between about 70 weight percent and about 90 weight percent vinylidene chloride as a barrier film, and a second outer layer of a second ethylene-vinyl acetate copolymer. The multilayer film is preferably made by co-extrusion of the layers, and then it is biaxially stretched. After biaxial stretching, the entire multilayer film is substantially uniformly irradiated to a dosage level of between about 2 megarads and about 3 megarads and heat-sealed in the form of a bag. The film is not significantly discoloured by the irradiation and the bag has improved toughness properties and heat-sealing characteristics

  4. Multilayered Josephson junction logic and memory devices

    International Nuclear Information System (INIS)

    Flux quantum logic and memory circuits using superconducting Josephson tunnel junctions have high-speed switching times (∼ 1 ps), low power dissipation (< 1 microW per circuit) and low levels of thermally induced electrical noise. Current designs of such circuits employ single trilayer junctions, which impose circuit size and logic threshold limitations. A new design component, the multilayered tunnel junction, consists of a vertically stacked array (a one dimensional superlattice) of Josephson tunnel junctions. The introduction of multilayered junctions into superconducting electronic circuitry offers a reduction in current device size, fault tolerances, and new device applications. The authors present numerical simulations of simple circuits employing multilayered Josephson junctions as design components. Comparison with conventional single flux quantum (SFQ) circuitry is discussed. They also present preliminary measurements of multilayered Josephson junctions fabricated for use in flux quantum devices

  5. Langmuir Blodgett multilayers and related nanostructures

    Indian Academy of Sciences (India)

    S S Major; S S Talwar; R S Srinivasa

    2006-07-01

    Langmuir Blodgett (LB) process is an important route to the development of organized molecular layered structures of a variety of organic molecules with suitably designed architecture and functionality. LB multilayers have also been used as templates and precursors to develop nano-structured thin films. In this article, studies on the molecular packing and three-dimensional structure of prototypic cadmium arachidate (CdA), zinc arachidate (ZnA) and mixed CdA–ZnA LB multilayers are presented. The formation of semiconducting nano-clusters of CdS, ZnS and CdZn1−S alloys within the organic multilayer matrix, using arachidate LB multilayers as precursors is also discussed.

  6. Training a Multilayer Perceptron to predict the final selling price of an apartment in co-operative housing society sold in Stockholm city with features stemming from open data. : MASTER'S PROJECT IN COMPUTER SCIENCE

    OpenAIRE

    Tibell, Rasmus

    2014-01-01

    The need for a robust model for predicting the value of condominiums and houses are becoming more apparent as further evidence of systematic errors in existing models are presented. Traditional valuation methods fail to produce good predictions of condominium sales prices and systematic patterns in the errors linked to for example the repeat sales methodology and the hedonic pricing model have been pointed out by papers referenced in this thesis. This inability can lead to monetary problems f...

  7. Spherical cloaking with homogeneous isotropic multilayered structures.

    Science.gov (United States)

    Qiu, Cheng-Wei; Hu, Li; Xu, Xiaofei; Feng, Yijun

    2009-04-01

    We propose a practical realization of electromagnetic spherical cloaking by layered structure of homogeneous isotropic materials. By mimicking the classic anisotropic cloak by many alternating thin layers of isotropic dielectrics, the permittivity and permeability in each isotropic layer can be properly determined by effective medium theory in order to achieve invisibility. The model greatly facilitates modeling by Mie theory and realization by multilayer coating of dielectrics. Eigenmode analysis is also presented to provide insights of the discretization in multilayers. PMID:19518392

  8. Multilayer Nanofilms as Substrates for Hepatocellular Applications

    OpenAIRE

    Wittmer, Corinne R.; Phelps, Jennifer A.; Lepus, Christin M.; Saltzman, W. Mark; Harding, Martha J.; van Tassel, Paul R

    2008-01-01

    Multilayer nanofilms, formed by the layer-by-layer (LbL) adsorption of positively and negatively charged polyelectrolytes, are promising substrates for tissue engineering. We investigate here the attachmemt and function of hepatic cells on multilayer films in terms of film composition, terminal layer, rigidity, charge, and presence of biofunctional species. Human hepatocellular carcinoma cells (HepG2), adult rat hepatocytes (ARH), and human fetal hepatoblasts (HFHb) are studied on films compo...

  9. Lipid layers on polyelectrolyte multilayer supports

    OpenAIRE

    Fischlechner, Martin; Zaulig, Markus; Meyer, Stefan; Estrela-Lopis, Irina; Cuéllar, Luis; Irigoyen, Joseba; Pescador, Paula; Brumen, Milan; Messner, Paul; Moya, Sergio; Donath, Edwin

    2008-01-01

    The mechanism of formation of supported lipid layers from phosphatidylcholine and phosphatidylserine vesicles in solution on polyelectrolyte multilayers was studied by a variety of experimental techniques. The interaction of zwitterionic and acidic lipid vesicles, as well as their mixtures, with polyelectrolyte supports was followed in real time by micro-gravimetry. The fabricated lipid–polyelectrolyte composite structures on top of multilayer coated colloidal particles were characterized by ...

  10. Pulsed laser deposition of multilayered structures

    Science.gov (United States)

    Jelinek, Miroslav; Olsan, V.; Trtik, V.

    1994-12-01

    Epitaxial superconductive and ferroelectric thin films, buffer layers and multilayers were created by laser ablation deposition on monocrystalline and technological substrates. Deposition of complex multilayer systems composed of YBaCuO, YSZ, ZrO2, CeO2, SrTiO3, PZT, PLZT, and PMN layers, and some properties of these systems characterized by XRD and electrical measurements are presented.

  11. Ordered organic-organic multilayer growth

    Energy Technology Data Exchange (ETDEWEB)

    Forrest, Stephen R.; Lunt, Richard R.

    2016-04-05

    An ordered multilayer crystalline organic thin film structure is formed by depositing at least two layers of thin film crystalline organic materials successively wherein the at least two thin film layers are selected to have their surface energies within .+-.50% of each other, and preferably within .+-.15% of each other, whereby every thin film layer within the multilayer crystalline organic thin film structure exhibit a quasi-epitaxial relationship with the adjacent crystalline organic thin film.

  12. Cylindrical multilayer metal-dielectric structures

    Science.gov (United States)

    Sasin, M. E.; Il'inskaya, N. D.; Zadiranov, Yu. M.; Kaliteevskaya, N. A.; Lazarenko, A. A.; Mazlin, V. A.; Brunkov, P. N.; Pavlov, S. I.; Kaliteevski, M. A.

    2015-11-01

    A method of creating a cylindrical structures consisting of thin metallic layer and dielectric multilayer Bragg reflector is described. Formation of the structures is observed experimentally as a result of separation and twisting away from the substrate a thin layer of gold coated with a multilayer SiO2/TiO2 Bragg reflector. It is suggested that such structures may be of interest for the creation of novel optoelectronic devices.

  13. Recurrence quantification analysis of chimera states

    Energy Technology Data Exchange (ETDEWEB)

    Santos, M.S. [Pós-Graduação em Ciências/Física, Universidade Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR (Brazil); Szezech, J.D., E-mail: jdanilo@gmail.com [Departamento de Matemática e Estatística, Universidade Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR (Brazil); Batista, A.M., E-mail: antoniomarcosbatista@gmail.com [Departamento de Matemática e Estatística, Universidade Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR (Brazil); Caldas, I.L. [Instituto de Física, Universidade de São Paulo, 05315-970, São Paulo, SP (Brazil); Viana, R.L.; Lopes, S.R. [Departamento de Física, Universidade Federal do Paraná, 81531-990, Curitiba, PR (Brazil)

    2015-10-02

    Chimera states, characterised by coexistence of coherence and incoherence in coupled dynamical systems, have been found in various physical systems, such as mechanical oscillator networks and Josephson-junction arrays. We used recurrence plots to provide graphical representations of recurrent patterns and identify chimera states. Moreover, we show that recurrence plots can be used as a diagnostic of chimera states and also to identify the chimera collapse. - Highlights: • Chimera states have been found in various physical systems. • Recurrence plots is a graphical method useful to locate recurring patterns. • We used recurrence plots to identify the chimera states. • We show also the recurrence plots can identify the chimera collapse.

  14. Recurrence quantification analysis of chimera states

    International Nuclear Information System (INIS)

    Chimera states, characterised by coexistence of coherence and incoherence in coupled dynamical systems, have been found in various physical systems, such as mechanical oscillator networks and Josephson-junction arrays. We used recurrence plots to provide graphical representations of recurrent patterns and identify chimera states. Moreover, we show that recurrence plots can be used as a diagnostic of chimera states and also to identify the chimera collapse. - Highlights: • Chimera states have been found in various physical systems. • Recurrence plots is a graphical method useful to locate recurring patterns. • We used recurrence plots to identify the chimera states. • We show also the recurrence plots can identify the chimera collapse

  15. Generalized Moshinsky bracket recurrence relations

    International Nuclear Information System (INIS)

    Recurrence relations for generalized Talmi-Moshinsky brackets are derived. These relations permit the generation of transformation brackets once appropriate starting brackets are determined. The savings in computer time, when compared with generating brackets individually, is at least a factor of 10 for brackets with radial quantum numbers as large as 9 and angular quantum numbers as large as 2. (author)

  16. Recurrent phaeohyphomycosis: a case report.

    Science.gov (United States)

    Shirbur, Sn; Telkar, Sr; Goudar, Bv; Mathew, Tony

    2013-09-01

    Phaeohyphomycoses are rare, opportunistic, fungal infections which are usually seen in immunocompromised individuals. We are reporting a case of a 40-year-old man with recurrent cutaneous phaeohyphomycosis, who did not have any clinical evidence of immunodeficiency, who presented with signs which resembled a malignancy of the skin. PMID:24179928

  17. Recurrent Phaeohyphomycosis: A Case Report

    OpenAIRE

    Shirbur, SN; Telkar, SR; Goudar, BV; Mathew, Tony

    2013-01-01

    Phaeohyphomycoses are rare, opportunistic, fungal infections which are usually seen in immunocompromised individuals. We are reporting a case of a 40-year-old man with recurrent cutaneous phaeohyphomycosis, who did not have any clinical evidence of immunodeficiency, who presented with signs which resembled a malignancy of the skin.

  18. Onychomycosis: Strategies to Minimize Recurrence.

    Science.gov (United States)

    Gupta, Aditya K; Elewski, Boni E; Rosen, Ted; Caldwell, Bryan; Pariser, David M; Kircik, Leon H; Bhatia, Neal; Tosti, Antonella

    2016-03-01

    Recurrence (relapse or re-infection) in onychomycosis is common, occurring in 10% to 53% of patients. However, data on prevalence is limited as few clinical studies follow patients beyond 12 months. It has been suggested that recurrence after continuous terbinafine treatment may be less common than with intermittent or continuous itraconazole therapy, probably due to the fungicidal activity of terbinafine, although these differences tended not to be significant. Relapse rates also increase with time, peaking at month 36. Although a number of factors have been suggested to play a role in recurrence, only the co-existence of diabetes has been shown to have a significant impact. Data with topical therapy is sparse; a small study showed amorolfine prophylaxis may delay recurrence. High concentrations of efinaconazole have been reported in the nail two weeks' post-treatment suggesting twice monthly prophylaxis with topical treatments may be a realistic option, and may be an important consideration in diabetic patients with onychomycosis. Data suggest that prophylaxis may need to be continued for up to three years for optimal effect. Treating tinea pedis and any immediate family members is also critical. Other preventative strategies include avoiding communal areas where infection can spread (such as swimming pools), and decontaminating footwear. J Drugs Dermatol. 2016;15(3):279-282. PMID:26954312

  19. Recurrence of benign spinal neoplasms.

    Science.gov (United States)

    Schick, U; Marquardt, G; Lorenz, R

    2001-03-01

    The outcome of surgical treatment of benign spinal neoplasms is considered to be excellent, with good improvement of neurological function. The risk of recurrence is estimated to be very low, except with subtotal resections. This retrospective study was designed to establish the course of illness, clinical outcome, and recurrence rate of benign spinal tumours. We present an overview of the clinical outcome and surgical treatment of 197 benign spinal tumours carried out in our centre from 1980 to 1999. Clinical history, signs, surgical approach, outcome, and radiological reports were obtained by reviewing patient charts. The most frequent benign tumour was meningeoma (41%), closely followed by neurinoma (33%) and neurofibroma (6.1%). Of all tumours, 79.7% were completely resected. Recurrence happened in 10.2% on an average of 4.3 years postoperatively. Only 2 patients suffered from neurofibromatosis. All neurinomas were completely resected at first operation, whereas three out of seven recurrent meningeomas and all ependymomas were classified as subtotally resected. Seventy per cent were treated by repeated surgical intervention. Benign tumours usually can be completely removed without adding to patients' neurological deficits. Benign tumours recur in 10.2% of cases, thus requiring long-term follow-up. Magnetic resonance imaging (MRI) studies are recommended up to 5 years postoperatively as a routine procedure. PMID:11339463

  20. Ovarian irradiation in recurrent endometriosis

    International Nuclear Information System (INIS)

    We describe a case of a young woman with a history of an aplastic anaemia in which pelvic radiotherapy was used successfully in the management of a recurrent and inoperable endometriosis. The use of therapeutic pelvic or ovarian irradiation in endometriosis may be considered, when surgical and medical treatments have been exhausted and have failed. (authors)

  1. Hyperthermia of recurrent breast sarcoma

    International Nuclear Information System (INIS)

    Full text: Breast sarcomas comprise approximately 3 % of all malignant breast tumors. The efficacy of adjuvant chemotherapy, hormone therapy or radiotherapy has not been proven. Recently, hyperthermia (HT) has been recognized as an effective adjuvant in treatment of locally advanced recurrent breast cancer. A 72-year-old female patient was admitted to our breast unit. In her history she had 10 resections for recurrent liposarcoma of the left breast over a period of 14 years, comprising resection of the infiltrated axillary vein. After a new wide resection and implantation of two interstitial devices HT was performed with a total number of 6 sessions over 3 weeks. The time for each session was 60 minutes. Temperature was exactly calibrated between 40 and 43 degrees Celsius. No notable complications were observed. The patient is free of local recurrence for a follow up period of 49 months. Our results suggest that local hyperthermia may be useful to prevent local recurrence in liposarcoma of the breast. The data should encourage further clinical studies. (author)

  2. Interpretation of Recurrent Neural Networks

    DEFF Research Database (Denmark)

    Pedersen, Morten With; Larsen, Jan

    This paper addresses techniques for interpretation and characterization of trained recurrent nets for time series problems. In particular, we focus on assessment of effective memory and suggest an operational definition of memory. Further we discuss the evaluation of learning curves. Various nume...

  3. Process capability of etched multilayer EUV mask

    Science.gov (United States)

    Takai, Kosuke; Iida nee Sakurai, Noriko; Kamo, Takashi; Morikawa, Yasutaka; Hayashi, Naoya

    2015-10-01

    With shrinking pattern size at 0.33NA EUV lithography systems, mask 3D effects are expected to become stronger, such as horizontal/vertical shadowing, best focus shifts through pitch and pattern shift through focus. Etched multilayer EUV mask structures have been proposed in order to reduce mask 3D effects. It is estimated that etched multilayer type mask is also effective in reducing mask 3D effects at 0.33NA with lithographic simulation, and it is experimentally demonstrated with NXE3300 EUV Lithography system. We obtained cross-sectional TEM image of etched multilayer EUV mask pattern. It is observed that patterned multilayer width differs from pattern physical width. This means that effective reflecting width of etched multilayer pattern is smaller than pattern width measured by CD-SEM. In this work, we evaluate mask durability against both chemical and physical cleaning process to check the feasibility of etched multilayer EUV mask patterning against mask cleaning for 0.33NA EUV extension. As a result, effective width can be controlled by suitable cleaning chemicals because sidewall film works as a passivation film. And line and space pattern collapse is not detected by DUV mask pattern inspection tool after mask physical cleaning that includes both megasonic and binary spray steps with sufficient particle removal efficiency.

  4. Capability of etched multilayer EUV mask fabrication

    Science.gov (United States)

    Takai, Kosuke; Murano, Koji; Kamo, Takashi; Morikawa, Yasutaka; Hayashi, Naoya

    2014-09-01

    Recently, development of next generation extremely ultraviolet lithography (EUVL) equipment with high-NA (Numerical Aperture) optics for less than hp10nm node is accelerated. Increasing magnification of projection optics or mask size using conventional mask structure has been studied, but these methods make lithography cost high because of low through put and preparing new large mask infrastructures. To avoid these issues, etched multilayer EUV mask has been proposed. As a result of improvement of binary etched multilayer mask process, hp40nm line and space pattern on mask (hp10nm on wafer using 4x optics) has been demonstrated. However, mask patterns are easily collapsed by wet cleaning process due to their low durability caused by high aspect ratio. We propose reducing the number of multilayer pairs from 40 to 20 in order to increase durability against multilayer pattern collapse. With 20pair multilayer blank, durable minimum feature size of isolated line is extended from 80nm to 56nm. CD uniformity and linearity of 20pair etched multilayer pattern are catching up EUV mask requirement of 2014.

  5. Clostridium difficile recurrences in Stockholm.

    Science.gov (United States)

    Sandell, Staffan; Rashid, Mamun-Ur; Jorup-Rönström, Christina; Ellström, Kristina; Nord, Carl Erik; Weintraub, Andrej

    2016-04-01

    Sixty-eight hospital-admitted patients with a first episode of Clostridium difficile infection (CDI) were included and followed up during 1 year. Faeces samples were collected at 1, 2, 6 and 12 months after inclusion and analyzed for the presence of C. difficile toxin B, genes for toxin A, toxin B, binary toxin and TcdC deletion by PCR. All strains were also PCR-ribotyped and the MICs of the isolates were determined against eight antimicrobial agents. In 68 patients initially included, antibiotics, clinical signs and co-morbidities were analyzed and 56 were evaluable for recurrences. The mean number of different antibiotics given during 3 months prior to inclusion was 2.6 (range 0-6). Six patients had not received any antibiotics and three of them had diagnosed inflammatory bowel disease. Thirty-two patients (57%) had either a microbiological or clinical recurrence, 16 of whom had clinical recurrences that were confirmed microbiologically (13, 23%) or unconfirmed by culture (3, 5%). Twenty-nine patients were positive in at least one of the follow-up tests, 16 had the same ribotype in follow-up tests, i.e. relapse, and 13 a different ribotype, i.e., reinfection. Most common ribotypes were 078/126, 020, 023, 026, 014/077, 001 and 005. No strain of ribotype 027 was found. Strains ribotype 078/126 and 023 were positive for binary toxin and were the strains most prone to cause recurrence. All strains were sensitive to vancomycin and metronidazole. Patients with recurrences were significantly older (p = 0.02) and all patients had a high burden of comorbidities, which could explain the high fatality rate, 26 (38%) patients died during the 1-year follow-up. PMID:26802875

  6. Giant recurrent retroperitoneal liposarcoma presenting as a recurrent inguinal hernia

    Directory of Open Access Journals (Sweden)

    Ajay H. Bhandarwar

    2011-11-01

    Full Text Available Retroperitoneal liposarcoma presenting as an inguinal hernia is a rare entity. We present the first case of Giant recurrent liposarcoma presenting as a recurrent inguinal hernia in a 40-year-old male. Physical examination showed an irreducible lump in the right inguinal region and a scar in the right lumbar and right inguinal region. Computed tomography (CT scan of abdomen revealed it to be a retro peritoneal mass extending into the right inguinal region along and involving the cord structures. Wide local excision of the tumour with right orchidectomy and inguinal hernioplasty was performed. Histo-pathology confirmed it to be a liposarcoma. Patient received postoperative radio therapy. Follow up of two years has shown him to be disease free. Retroperitoneal liposarcoma can grow along cord structures into the inguinal canal and mimic an irreducible indirect inguinal hernia.

  7. Giant recurrent retroperitoneal liposarcoma presenting as a recurrent inguinal hernia

    Science.gov (United States)

    Bhandarwar, Ajay H.; Bakhshi, Girish D.; Borisa, Ashok D.; Shenoy, Sachin S.; Kori, Channabasappa G.; Vora, Sameer

    2011-01-01

    Retroperitoneal liposarcoma presenting as an inguinal hernia is a rare entity. We present the first case of Giant recurrent liposarcoma presenting as a recurrent inguinal hernia in a 40-year-old male. Physical examination showed an irreducible lump in the right inguinal region and a scar in the right lumbar and right inguinal region. Computed tomography (CT) scan of abdomen revealed it to be a retro peritoneal mass extending into the right inguinal region along and involving the cord structures. Wide local excision of the tumour with right orchidectomy and inguinal hernioplasty was performed. Histo-pathology confirmed it to be a liposarcoma. Patient received postoperative radio therapy. Follow up of two years has shown him to be disease free. Retroperitoneal liposarcoma can grow along cord structures into the inguinal canal and mimic an irreducible indirect inguinal hernia. PMID:24765371

  8. Fifth International Symposium on Recurrence Plot

    CERN Document Server

    Riley, Michael; Giuliani, Alessandro; Webber, Charles; Jr, Jr; Translational Recurrences : From Mathematical Theory to Real-World Applications

    2014-01-01

    This book features 13 papers presented at the Fifth International Symposium on Recurrence Plots, held August 2013 in Chicago, IL. It examines recent applications and developments in recurrence plots and recurrence quantifi cation analysis (RQA) with special emphasis on biological and cognitive systems and the analysis of coupled systems using cross-recurrence methods. Readers will discover new applications and insights into a range of systems provided by recurrence plot analysis and new theoretical and mathematical developments in recurrence plots. Recurrence plot based analysis is a powerful tool that operates on real-world complex systems that are nonlinear, non-stationary, noisy, of any statistical distribution, free of any particular model type, and not particularly long. Quantitative analyses promote the detection of system state changes, synchronized dynamical regimes, or classifi cation of system states. Th e book will be of interest to an interdisciplinary audience of recurrence plot users and researc...

  9. Interference in multilayer relativistic mirrors

    Science.gov (United States)

    Mirzanejhad, Saeed; Sohbatzadeh, Farshad; Babaei, Javad; Taghipour, Meisam; Mohammadzadeh, Zahra

    2015-10-01

    In this paper, reflection coefficient of a relativistic ultra-thin electron multilayer is calculated using electromagnetic interference procedures. The relativistic electron layers are assumed to be formed by nonlinear plasma wake waves that constitute the electron density cusps. It is shown that the interference between successive relativistic mirrors is restricted by the condition, τ p ≫ ( 2 γ 0 ) 5 / 2 / ω p 0 , where τp is the laser pulse duration. The results showed that tailoring the pulse amplitude, incident wave frequency value, incidence angle, and plasma density leads to increasing reflection coefficient a few orders of magnitudes. This constructive interference condition can be used for increasing conversion efficiency in the reflected energy from relativistic mirrors for the purpose of generating ultra-short coherence pulses in the extreme ultraviolet and x-ray regions. We also performed reflection from relativistic thin electron layers using relativistic 1D3V electromagnetic particle-in-cell (PIC) simulation. It was found that the results of PIC simulation are in agreement with analytical considerations.

  10. Supplemental multilayer insulation research facility

    International Nuclear Information System (INIS)

    The Supplemental Multilayer Insulation Research Facility (SMIRF) provides a small scale test bed for conducting cryogenic experiments in a vacuum environment. The facility vacuum system is capable of simulating a Space Shuttle launch pressure profile as well as providing a steady space vacuum environment of 1.3x10-4 N/m2(1 x 10-6 torr). Warm side boundary temperatures can be maintained constant between 111 K(200 R) and 361 K(650 R) using a temperature controlled shroud. The shroud can also simulate a typical lunar day-night temperature profile. The test hardware consists of a cryogenic calorimeter supported by the lid of the vacuum chamber. A 0.45 m3 (120 gal) vacuum jacketed storage/supply tank is available for conditioning the cryogen prior to use in the calorimeter. The facility was initially designed to evaluate the thermal performance of insulation systems for long-term storage in space. The facility has recently been used to evaluate the performance of various new insulation systems for LH2 and LN2 ground storage dewars

  11. Multilayer Piezoelectric Stack Actuator Characterization

    Science.gov (United States)

    Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph

    2008-01-01

    Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

  12. Multilayer heterostructures and their manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, Scott R; Reese, Matthew; Rupert, Benjamin; Miedaner, Alexander; Curtis, Clavin; Olson, Dana; Ginley, David S

    2015-11-04

    A method of synthesizing multilayer heterostructures including an inorganic oxide layer residing on a solid substrate is described. Exemplary embodiments include producing an inorganic oxide layer on a solid substrate by a liquid coating process under relatively mild conditions. The relatively mild conditions include temperatures below 225.degree. C. and pressures above 9.4 mb. In an exemplary embodiment, a solution of diethyl aluminum ethoxide in anhydrous diglyme is applied to a flexible solid substrate by slot-die coating at ambient atmospheric pressure, and the diglyme removed by evaporation. An AlO.sub.x layer is formed by subjecting material remaining on the solid substrate to a relatively mild oven temperature of approximately 150.degree. C. The resulting AlO.sub.x layer exhibits relatively high light transmittance and relatively low vapor transmission rates for water. An exemplary embodiment of a flexible solid substrate is polyethylene napthalate (PEN). The PEN is not substantially adversely affected by exposure to 150.degree. C

  13. ON-RECURRENT LORENTZIAN -KENMOTSU MANIFOLDS

    OpenAIRE

    SREENIVASA, G.T.; VENKATESHA, VENKATESHA; C. S. Bagewadi; NAGANAGOUD, K.

    2009-01-01

    Abstract: In this paper, we study Lorentzian -Kenmotsu manifold and we shown that -recurrent Lorentzian -Kenmotsu manifold is an Einstein manifold and a pseudo-projective -recurrent Lorentzian -Kenmotsu manifold is an - Einstein manifold. And also we get the expression for 1-form A in a -recurrent Lorentzian -Kenmotsu manifold. Key words: -Kenmotsu manifold, locally pseudo-projective -symmetric manifold, -recurrent Lorentzian -Kenmotsu manifold, Einstein manifold, -Einstein manifo...

  14. 14 CFR 121.427 - Recurrent training.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Recurrent training. 121.427 Section 121.427..., FLAG, AND SUPPLEMENTAL OPERATIONS Training Program § 121.427 Recurrent training. (a) Recurrent training must ensure that each crew member or dispatcher is adequately trained and currently proficient...

  15. 14 CFR 91.1107 - Recurrent training.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Recurrent training. 91.1107 Section 91.1107... Management § 91.1107 Recurrent training. (a) Each program manager must ensure that each crewmember receives recurrent training and is adequately trained and currently proficient for the type aircraft and...

  16. 14 CFR 135.351 - Recurrent training.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Recurrent training. 135.351 Section 135.351... AND ON DEMAND OPERATIONS AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Training § 135.351 Recurrent training. (a) Each certificate holder must ensure that each crewmember receives recurrent...

  17. Strong laws for recurrence quantification analysis

    OpenAIRE

    Grendár, Marian; Majerová, Jana; Špitalský, Vladimír

    2013-01-01

    The recurrence rate and determinism are two of the basic complexity measures studied in the recurrence quantification analysis. In this paper, the recurrence rate and determinism are expressed in terms of the correlation sums, and strong laws of large numbers are given for them.

  18. Immunopathogenesis of recurrent vulvovaginal candidiasis.

    OpenAIRE

    Fidel, P. L.; Sobel, J D

    1996-01-01

    Recurrent vulvovaginal candidiasis (RVVC) is a prevalent opportunistic mucosal infection, caused predominantly by Candida albicans, which affects a significant number of otherwise healthy women of childbearing age. Since there are no known exogenous predisposing factors to explain the incidence of symptomatic vaginitis in most women with idiopathic RVVC, it has been postulated that these particular women suffer from an immunological abnormality that prediposes them to RVVC. Because of the inc...

  19. Hypocortisolism in recurrent affective disorders

    OpenAIRE

    Maripuu, Martin

    2015-01-01

    Bipolar disorders and recurrent depressions are two common psychiatric disorders with a life time prevalence of approximately 1% and 8%, respectively. Despite treatment these patients suffer from affective symptoms up to 50% of the time, resulting in lower well-being. The average life length is also reduced with 10-15 years, mainly attributable to suicide and cardiovascular disease. Increased stress is one of many factors that have been shown to be linked to an increased risk for developing a...

  20. Recurrent artery of Heubner aneurysm

    OpenAIRE

    Vellore, Yagnesh; Madan, Anoop; Hwang, Peter Yin Kai

    2014-01-01

    True Recurrent artery of Heubner (RAH) aneurysms are extremely rare and only three cases have been reported in the literature. We report a case of RAH aneurysm in a patient with World Federation of Neurosurgical Societies grade one subarachnoid hemorrhage (SAH), detected only on delayed cerebral angiography. We propose that an aneurysm in this location should be considered in the differential diagnosis of angiogram-negative SAH, and all vascular imaging studies be carefully scrutinized for RA...

  1. MR investigation of recurrent cholesteatomas

    International Nuclear Information System (INIS)

    Nine cases of recurrent petrous cholesteatomas have been studied by a 1.5 T MR unit. Gadolinium was injected in 1 case. In all cases, comparison between MR, CT and clinical findings were made. MR allows for accurate topographic study and assessment of cholesteatomas extension, in particular in the posterior fossa and skull base. Relationships with the internal carotid artery and the jugular vein are clearly depicted

  2. Factors predicting recurrent endometrial cancer

    OpenAIRE

    Huijgens, A.N.J.; Mertens, H.J.M.M.

    2013-01-01

    Objectives: The aim of this study was to identify (prognostic) factors that may predict the development of recurrent endometrial cancer and may improve the choice of adjuvant therapy subsequently. Methods: Data of all patients, diagnosed with primary endometrial cancer in Orbis Medical Center Sittard between 2002 and 2010, were analyzed retrospectively. Cox regression analysis was performed for identification of independent prognostic factors; survival was calculated by using the Kaplan-Meier...

  3. Pinealitis accompanying equine recurrent uveitis.

    OpenAIRE

    Kalsow, C M; Dwyer, A E; Smith, A. W.; Nifong, T P

    1993-01-01

    There is no direct verification of pineal gland involvement in human uveitis. Specimens of pineal tissue are not available during active uveitis in human patients. Naturally occurring uveitis in horses gives us an opportunity to examine tissues during active ocular inflammation. We examined the pineal gland of a horse that was killed because it had become blind during an episode of uveitis. The clinical history and histopathology of the eyes were consistent with post-leptospiral equine recurr...

  4. [Recurrent erysipelas and cellulitis: management].

    Science.gov (United States)

    Zürcher, Sven; Trellu, Laurence Toutous

    2015-04-01

    Erysipelas and infectious cellulitis are skin infections that develop following the entry of bacteria through gaps in the skin. The most common complication is recurrence. Control of predisposing factors remains essential to prevent it. Prophylactic antibiotics are sometimes prescribed, but this approach is based on small studies and expert opinion. This article reflects the current state of knowledge and the standard of care. PMID:26021136

  5. RECURRENT HAEMETEMESIS: THE MYSTERY UNFOLDS

    Directory of Open Access Journals (Sweden)

    Nayantara Rao

    2014-11-01

    Full Text Available This report presents the case history of a six year old child who was portrayed as having recurrent haemetemesis since two years by her mother. A detailed evaluation showed that the patient’s history was inconsistent with the clinical findings and investigations, leading to a diagnosis of Factitious Disorder by Proxy (FDbp. The report highlights the rationale for under-diagnosis of FDbp in India and challenges the conventional approach ( Parentectomy for treating FDbp.

  6. High-resolution X-ray Multilayers

    International Nuclear Information System (INIS)

    Two new approaches are taken in multilayer fabrication to help bridge the gap in bandwidth between traditional multilayers (1 to 2%) and perfect crystals (0.01%). The first approach is based on creating many layers of low-contrast Al2O3/ B4C materials. The second approach is based on using multilayer structures with a small d-spacing using traditional W/B4C and Mo/B4C materials. With 8 keV x-rays on the Chess A2 beamline, we measured a bandwidth of 0.27% with a reflectivity of 40% and a Darwin width of 17 arc seconds from a 26 A d-spacing multilayer with 800 bi-layers of Al2O3/B4C using the low-contrast approach. On the other hand, the short period approach with a W/B4C multilayer and a 14.8 A d-spacing showed a resolution of 0.5 % and a reflectivity of 58.5%. Two more Mo/B4C samples with d-spacings of 15 A and 20 A showed energy resolutions of 0.25% and 0.52% with corresponding reflectivities of 39% and 66%. Thus we observe that both methods can produce useful x-ray optical components

  7. Refractive index contrast in porous silicon multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Nava, R.; Mora, M.B. de la; Tagueena-Martinez, J. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Temixco, Morelos (Mexico); Rio, J.A. del [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Temixco, Morelos (Mexico); Centro Morelense de Innovacion y Transferencia Tecnologica, Consejo de Ciencia y Tecnologia del Estado de Morelos (Mexico)

    2009-07-15

    Two of the most important properties of a porous silicon multilayer for photonic applications are flat interfaces and a relative large refractive index contrast between layers in the optical wavelength range. In this work, we studied the effect of the current density and HF electrolyte concentration on the refractive index of porous silicon. With the purpose of increasing the refractive index contrast in a multilayer, the refractive index of porous silicon produced at low current was studied in detail. The current density applied to produce the low porosity layers was limited in order to keep the electrolyte flow through the multilayer structure and to avoid deformation of layer interfaces. We found that an electrolyte composed of hydrofluoric acid, ethanol and glycerin in a ratio of 3:7:1 gives a refractive index contrast around 1.3/2.8 at 600 nm. Several multilayer structures with this refractive index contrast were fabricated, such as dielectric Bragg mirrors and microcavities. Reflectance spectra of the structures show the photonic quality of porous silicon multilayers produced under these electrochemical conditions. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Base Metal Co-Fired Multilayer Piezoelectrics

    Directory of Open Access Journals (Sweden)

    Lisheng Gao

    2016-03-01

    Full Text Available Piezoelectrics have been widely used in different kinds of applications, from the automobile industry to consumer electronics. The novel multilayer piezoelectrics, which are inspired by multilayer ceramic capacitors, not only minimize the size of the functional parts, but also maximize energy efficiency. Development of multilayer piezoelectric devices is at a significant crossroads on the way to achieving low costs, high efficiency, and excellent reliability. Concerning the costs of manufacturing multilayer piezoelectrics, the trend is to replace the costly noble metal internal electrodes with base metal materials. This paper discusses the materials development of metal co-firing and the progress of integrating current base metal chemistries. There are some significant considerations in metal co-firing multilayer piezoelectrics: retaining stoichiometry with volatile Pb and alkaline elements in ceramics, the selection of appropriate sintering agents to lower the sintering temperature with minimum impact on piezoelectric performance, and designing effective binder formulation for low pO2 burnout to prevent oxidation of Ni and Cu base metal.

  9. Elastic properties of suspended multilayer WSe2

    International Nuclear Information System (INIS)

    We report the experimental determination of the elastic properties of suspended multilayer WSe2, a promising two-dimensional (2D) semiconducting material combined with high optical quality. The suspended WSe2 membranes have been fabricated by mechanical exfoliation of bulk WSe2 and transfer of the exfoliated multilayer WSe2 flakes onto SiO2/Si substrates pre-patterned with hole arrays. Then, indentation experiments have been performed on these membranes with an atomic force microscope. The results show that the 2D elastic modulus of the multilayer WSe2 membranes increases linearly while the prestress decreases linearly as the number of layers increases. The interlayer interaction in WSe2 has been observed to be strong enough to prevent the interlayer sliding during the indentation experiments. The Young's modulus of multilayer WSe2 (167.3 ± 6.7 GPa) is statistically independent of the thickness of the membranes, whose value is about two thirds of other most investigated 2D semiconducting transition metal dichalcogenides, namely, MoS2 and WS2. Moreover, the multilayer WSe2 can endure ∼12.4 GPa stress and ∼7.3% strain without fracture or mechanical degradation. The 2D WSe2 can be an attractive semiconducting material for application in flexible optoelectronic devices and nano-electromechanical systems

  10. Dynamical systems with low recurrence rate

    International Nuclear Information System (INIS)

    The question on the recurrence rate of a dynamical system in a metric space of finite Hausdorff measure is considered. For such systems upper bounds for the rate of simple recurrence are due to Boshernitzan and ones for the rate of multiple recurrence to the present author. The paper is concerned with finding lower bounds for the rate of multiple recurrence. More precisely, an example of a dynamical system (an odometer or a von Neumann transformation) with a low rate of multiple recurrence is constructed. Behrend's theorem on sets containing no arithmetic progressions is used in the proof.

  11. Stress Reduction in Improving Quality of Life in Patients With Recurrent Gynecologic or Breast Cancer

    Science.gov (United States)

    2015-10-08

    Anxiety Disorder; Depression; Fatigue; Leydig Cell Tumor; Ovarian Sarcoma; Ovarian Stromal Cancer; Pain; Peritoneal Carcinomatosis; Pseudomyxoma Peritonei; Recurrent Breast Cancer; Recurrent Cervical Cancer; Recurrent Endometrial Carcinoma; Recurrent Fallopian Tube Cancer; Recurrent Gestational Trophoblastic Tumor; Recurrent Ovarian Epithelial Cancer; Recurrent Ovarian Germ Cell Tumor; Recurrent Primary Peritoneal Cavity Cancer; Recurrent Uterine Sarcoma; Recurrent Vaginal Cancer; Recurrent Vulvar Cancer

  12. Multilayer cladding with hyperbolic dispersion for plasmonic waveguides

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Shalaginov, Mikhail Y.; Ishii, Satoshi; Boltasseva, Alexandra; Kildishev, Alexander V.

    2015-01-01

    We study the properties of plasmonic waveguides with a dielectric core and multilayer metal-dielectric claddings that possess hyperbolic dispersion. The waveguides hyperbolic multilayer claddings show better performance in comparison to conventional plasmonic waveguides. © OSA 2015....

  13. Magnetic properties of Ni/Pt multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Benkirane, K. [Laboratoire de Traitement d' information, Faculte des Sciences Ben' Msik Sidi-Othmane, B.P. 7955, Sidi-Othmane, Casablanca (Morocco)]. E-mail: karbenkirane@yahoo.fr; Elkabil, R. [Laboratoire de Traitement d' information, Faculte des Sciences Ben' Msik Sidi-Othmane, B.P. 7955, Sidi-Othmane, Casablanca (Morocco); Lassri, M. [Laboratoire de Physique des Materiaux et de Micro-electronique, Faculte des Sciences Ain Chock, Universite Hassan II, B.P. 5366 Ma-hat arif, Route d' El Jadida, km-8, Casablanca, Marocco (Morocco); Abid, M. [Laboratoire de Physique des Materiaux et de Micro-electronique, Faculte des Sciences Ain Chock, Universite Hassan II, B.P. 5366 Ma-hat arif, Route d' El Jadida, km-8, Casablanca, Marocco (Morocco); Lassri, H. [Laboratoire de Physique des Materiaux et de Micro-electronique, Faculte des Sciences Ain Chock, Universite Hassan II, B.P. 5366 Ma-hat arif, Route d' El Jadida, km-8, Casablanca, Marocco (Morocco); Berrada, A. [Laboratoire de Physique des Materiaux, Faculte des Sciences, Avenue Ibn Batouta, B.P. 1014, Rabat (Morocco); Hamdoun, A. [Laboratoire de Traitement d' information, Faculte des Sciences Ben' Msik Sidi-Othmane, B.P. 7955, Sidi-Othmane, Casablanca (Morocco); Krishnan, R. [Laboratoire de Magnetisme et d' Optique, URA 1531, 45 Avenue des Etats Unis, 78035 Versailles Cedex (France)

    2005-01-15

    We have grown Ni/Pt multilayers with Pt buffer layer, by evaporation under UHV conditions on glass substrates maintained at 300 K. The magnetic properties of Ni/Pt multilayers are examined as a function of Ni layer thickness t {sub Ni}. The temperature dependence of the spontaneous magnetization M(T) is well described by a T {sup 3/2} law in all multilayers. A spin-wave theory has been used to explain the temperature dependence of the magnetization and the approximate values for the bulk exchange interaction J {sub b}, surface exchange interaction J {sub S} and the interlayer coupling strength J {sub I} for various Ni layer thicknesses have been obtained.

  14. Long Range Surface Plasmons in Multilayer Structures

    CERN Document Server

    Delfan, Aida

    2013-01-01

    We present a new strategy, based on a Fresnel coefficient pole analysis, for designing an asymmetric multilayer structure that supports long range surface plasmons (LRSP). We find that the electric field intensity in the metal layer of a multilayer LRSP structure can be even slightly smaller than in the metal layer of the corresponding symmetric LRSP structure, minimizing absorption losses and resulting in LRSP propagation lengths up to 2mm. With a view towards biosensing applications, we also present semi-analytic expressions for a standard surface sensing parameter in arbitrary planar resonant structures, and in particular show that for an asymmetric structure consisting of a gold film deposited on a multilayer of SiO2 and TiO2 a surface sensing parameter G = 1.28(1/nm) can be achieved.

  15. Multilayer Integrated Film Bulk Acoustic Resonators

    CERN Document Server

    Zhang, Yafei

    2013-01-01

    Multilayer Integrated Film Bulk Acoustic Resonators mainly introduces the theory, design, fabrication technology and application of a recently developed new type of device, multilayer integrated film bulk acoustic resonators, at the micro and nano scale involving microelectronic devices, integrated circuits, optical devices, sensors and actuators, acoustic resonators, micro-nano manufacturing, multilayer integration, device theory and design principles, etc. These devices can work at very high frequencies by using the newly developed theory, design, and fabrication technology of nano and micro devices. Readers in fields of IC, electronic devices, sensors, materials, and films etc. will benefit from this book by learning the detailed fundamentals and potential applications of these advanced devices. Prof. Yafei Zhang is the director of the Ministry of Educations Key Laboratory for Thin Films and Microfabrication Technology, PRC; Dr. Da Chen was a PhD student in Prof. Yafei Zhangs research group.

  16. Multilayer neural networks a generalized net perspective

    CERN Document Server

    Krawczak, Maciej

    2013-01-01

    The primary purpose of this book is to show that a multilayer neural network can be considered as a multistage system, and then that the learning of this class of neural networks can be treated as a special sort of the optimal control problem. In this way, the optimal control problem methodology, like dynamic programming, with modifications, can yield a new class of learning algorithms for multilayer neural networks. Another purpose of this book is to show that the generalized net theory can be successfully used as a new description of multilayer neural networks. Several generalized net descriptions of neural networks functioning processes are considered, namely: the simulation process of networks, a system of neural networks and the learning algorithms developed in this book. The generalized net approach to modelling of real systems may be used successfully for the description of a variety of technological and intellectual problems, it can be used not only for representing the parallel functioning of homogen...

  17. Mechanical properties of polyelectrolyte multilayer microcapsules

    Energy Technology Data Exchange (ETDEWEB)

    Vinogradova, Olga I [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Laboratory of Physical Chemistry of Modified Surfaces, Institute of Physical Chemistry, Russian Academy of Sciences, 31 Leninsky Prospect, 119991 Moscow (Russian Federation)

    2004-08-18

    Polyelectrolyte multilayer microcapsules were recently suggested as a new type of nanoengineered microstructures and are potentially important in many areas of science and technology. The present review focuses on the mechanics of these microstructures, emphasizing novel experimental approaches and the main experimental observations. Methods based on confocal and atomic force microscopy-osmotic buckling, osmotic swelling, and compression experiments-are detailed. Also covered is the preparation of multilayer microcapsules and various encapsulation techniques. A discussion of the theoretical models suggested is given. Special emphasis is given to the analysis of experimental data. This covers regimes of deformations, the roles of elasticity and permeability in determining the capsule stiffness, the effects of ageing, molecular weight, pH, salt concentration, and organic solvent on the multilayer shell properties, a contribution from encapsulated (charged and neutral) polymers, and more. (topical review)

  18. Community Detection Using Multilayer Edge Mixture Model

    CERN Document Server

    Zhang, Han; Lai, Jian-Huang; Yu, Philip S

    2016-01-01

    A wide range of complex systems can be modeled as networks with corresponding constraints on the edges and nodes, which have been extensively studied in recent years. Nowadays, with the progress of information technology, systems that contain the information collected from multiple perspectives have been generated. The conventional models designed for single perspective networks fail to depict the diverse topological properties of such systems, so multilayer network models aiming at describing the structure of these networks emerge. As a major concern in network science, decomposing the networks into communities, which usually refers to closely interconnected node groups, extracts valuable information about the structure and interactions of the network. Unlike the contention of dozens of models and methods in conventional single-layer networks, methods aiming at discovering the communities in the multilayer networks are still limited. In order to help explore the community structure in multilayer networks, we...

  19. Thermal performance of multilayer insulation. Part 2

    International Nuclear Information System (INIS)

    A new heat-flux model that is able to explain the two thermal-conduction terms in the prediction-based heat-flux equation of multilayer insulation is proposed. Based on the new model, the expansion and applicability of the equation to various parameters of multilayer insulation are examined in detail. The prediction equation was derived from various parameters and the predicted heat-flux values were evaluated. The treatment parameters were the mesh size of the net, the number of layers of net inserted between films, film thickness, single- vs. double-aluminized films, the winding method for the multilayer insulation, the layer density, and the hot and cold boundary temperatures. Predicted values for the various parameters coincided well with measured values

  20. Evolutionary games on multilayer networks: A colloquium

    CERN Document Server

    Wang, Zhen; Szolnoki, Attila; Perc, Matjaz

    2015-01-01

    Networks form the backbone of many complex systems, ranging from the Internet to human societies. Accordingly, not only is the range of our interactions limited and thus best described and modeled by networks, it is also a fact that the networks that are an integral part of such models are often interdependent or even interconnected. Networks of networks or multilayer networks are therefore a more apt description of social systems. This colloquium is devoted to evolutionary games on multilayer networks, and in particular to the evolution of cooperation as one of the main pillars of modern human societies. We first give an overview of the most significant conceptual differences between single-layer and multilayer networks, and we provide basic definitions and a classification of the most commonly used terms. Subsequently, we review fascinating and counterintuitive evolutionary outcomes that emerge due to different types of interdependencies between otherwise independent populations. The focus is on coupling th...

  1. Magnetic studies of Fe/Cu multilayers

    Energy Technology Data Exchange (ETDEWEB)

    El Khiraoui, S. [Laboratoire de Physique et Mecanique des Materiaux, Universite Sultan Moulay Slimane, FST de Beni-Mellal, B.P. 523, 23000 Beni-Mellal (Morocco); Sajieddine, M. [Laboratoire de Physique et Mecanique des Materiaux, Universite Sultan Moulay Slimane, FST de Beni-Mellal, B.P. 523, 23000 Beni-Mellal (Morocco)], E-mail: sajieddinem@yahoo.fr; Hehn, M.; Robert, S.; Lenoble, O.; Bellouard, C. [Laboratoire de Physique des Materiaux, UMR-CNRS 7556, B.P. 239, 54506 Vandoeuvre-les-Nancy Cedex (France); Sahlaoui, M. [Laboratoire de Physique et Mecanique des Materiaux, Universite Sultan Moulay Slimane, FST de Beni-Mellal, B.P. 523, 23000 Beni-Mellal (Morocco); Benkirane, K. [Laboratoire des Materiaux, Micro-electronique, Automatique et Thermique, Faculte des Sciences Ain-Chock, Universite Hassan II, B.P. 5366 Maarif, Casablanca (Morocco)

    2008-07-01

    The structural and magnetic properties of sputtered Fe/Cu multilayers are examined as a function of Fe layer thickness t{sub Fe} by means of X-ray diffraction, Moessbauer spectrometry and superconducting quantum interference magnetometer. The temperature dependence of the spontaneous magnetization M(T) is well described by a T{sup 3/2} law in all multilayers in the temperature range 5-300 K. The interface anisotropy constant of Fe/Cu multilayers, K{sub s}, is found to be 0.31 and 0.45 erg/cm{sup 2} at 5 and 300 K, respectively. A spin-wave theory has been used to explain the temperature dependence of the magnetization and the approximate values for the bulk exchange interaction J{sub b}, surface exchange interaction J{sub s} and the interlayer coupling strength J{sub I} for various Fe layer thicknesses have been obtained.

  2. Magnetic characterization of U/Co multilayers

    International Nuclear Information System (INIS)

    With the aim of expanding the studies on 2D systems containing uranium, U/Co multilayers with layer thickness ranging from 50 to 200 A were recently prepared by dc magnetron sputtering onto glass. The multilayers were characterized by Grazing-Incidence X-Ray Diffraction (GIXRD) and Rutherford Backscattering Spectrometry (RBS). Magnetization measurements performed with a squid magnetometer showed that the multilayers have a ferromagnetic behaviour, with the magnetic signal increasing with the thickness of the layers. The analysis of magnetic anisotropy evidenced an easy magnetic direction in the film plane with large anisotropy fields, which increase with the thickness of the layers and suggests a positive contribution of surface anisotropy to the effective anisotropy Keff. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  3. Performance of multilayer coated silicon pore optics

    DEFF Research Database (Denmark)

    Ackermann, M. D.; Collon, M. J.; Cooper-Jensen, Carsten P.; Christensen, Finn Erland; Krumrey, M.; Cibik, L.; Marggraf, S.; Bavdaz, M.; Lumb, D.; Shortt, B.

    2010-01-01

    simultaneously requirements for effective area of 2.5 m2 at 1.25 keV, 0.65 m2 at 6 keV and 150 cm2 at 30 keV. The reflectivity of the bare mirror substrate materials does not allow these requirements to be met. As such the IXO baseline design contains a coating layout that varies as a function of mirror radius...... and in accordance with the variation in grazing incidence angle. The higher energy photon response is enhanced through the use of depth-graded multilayer coatings on the inner radii mirror modules. In this paper we report on the first reflectivity measurements of wedged ribbed silicon pore optics...... mirror plates coated with a depth graded W/Si multilayer. The measurements demonstrate that the deposition and performance of the multilayer coatings is compatible with the SPO production process....

  4. Recent advances in etched multilayer X-ray optics

    OpenAIRE

    André, J.; Sammar, A.; Bac, S.; Ouahabi, M.; M. IDIR; Soullié, G.; Barchewitz, R

    1994-01-01

    We present the recent advances achieved in the Laboratoire de Chimie Physique of Université Paris 6, in the field of the soft X-ray etched multilayer optics. Modellings and characterizations are given for the laminar multilayer amplitude gratings, the highly resolutive X-ray multilayer monochromators, the X-ray polychromators and the Bragg-Fresnel multilayer linear lenses.


  5. Physical and chemical characterization of multilayered structures

    International Nuclear Information System (INIS)

    It is important to know the physical and chemical properties of a multilayer if its performance is to be compared to theoretical predictions, or if guidance is needed for the production of superior multilayers. Accurate, nondestructive analytical methods, such as neutron activation analysis, are restricted to certain elements. Certain destructive methods, such as total carbon analysis by combustion, can be sensitive enough for use with very small samples. The method of choice depends upon sensitivity and specificity, both of which are discussed in this paper. 6 refs., 3 figs., 2 tabs

  6. Exchange interactions in Fe/Y multilayers

    International Nuclear Information System (INIS)

    The magnetization of Fe/Y multilayers has been measured as a function of temperature. A bulk-like T 3/2 temperature dependence of the magnetization is observed for all multilayers in the temperature range 5-300 K. The spin-wave constant B is found to decrease inversely with t Fe. A simple theoretical model with exchange interactions only, and with non-interacting magnons, has been used to explain the temperature dependence of the magnetization and the approximate values for the bulk exchange interaction J b, surface exchange interaction J s and the interlayer exchange interaction J I for various Fe layer thicknesses have been obtained

  7. Magnetostriction of Co/Pd multilayers

    Science.gov (United States)

    Schelp, L. F.; Viegas, A. D. C.; Carara, M.; Schmidt, J. E.

    1995-01-01

    We have performed magnetostriction measurements on Co/Pd multilayers with different Co and Pd layer thicknesses. The features of the curves as a function of the applied field are strongly related to the magnetic easy axis orientation and, consequently, to the Co layer thickness, and also to the presence of Pd at the interfaces. We present an averaging procedure that explains the observed experimental results and allows the extraction of the in-plane magnetostriction coefficients of the multilayer if the initial magnetic moment distribution without field is obtained independently.

  8. Tunable self-organization of nanocomposite multilayers

    International Nuclear Information System (INIS)

    In this letter we report the controlled growth and microstructural evolution of self-assembled nanocomposite multilayers that are induced by surface ion-impingement. The nanoscale structures together with chemical composition, especially at the growing front, have been investigated with high-resolution transmission electron microscopy. Concurrent ion impingement of growing films produces an amorphous capping layer 3 nm in thickness where spatially modulated phase separation is initiated. It is shown that the modulation of multilayers as controlled by the self-organization of nanocrystallites below the capping layer, can be tuned through the entire film.

  9. YBCO based multilayers for optoelectronic devices

    International Nuclear Information System (INIS)

    YBCO based multilayers have been deposited independently by three techniques: laser ablation, inverted cylindrical target sputtering (ICM) and on-axis planar D.C. Magnetron Sputtering. The last technique is used to cover uniformly R-plane sapphire and LaAlO3 2 inch wafers with YBCO or multilayers to achieve optoelectronic devices such as infrared detectors. Very thin (- 3 nm) YSZ and MgO dielectric films have been studied as tunnel barriers for making such high Tc tunnel junctions. 14 refs., 11 figs

  10. Synthesis and electrical conductivity of multilayer silicene

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, P., E-mail: patrick.vogt@tu-berlin.de, E-mail: bruno.grandidier@isen.iemn.univ-lille1.fr; Bruhn, T. [Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin (Germany); Capiod, P.; Berthe, M.; Grandidier, B., E-mail: patrick.vogt@tu-berlin.de, E-mail: bruno.grandidier@isen.iemn.univ-lille1.fr [Institut d' Electronique, de Microélectronique et de Nanotechnologies (IEMN), CNRS, UMR 8520 Département ISEN, 41 bd Vauban, 59046 Lille Cedex (France); Resta, A. [Aix-Marseille University, CNRS-CINaM, Campus de Luminy, Case 913, F-13288 Marseille Cedex 09 (France); De Padova, P. [Instituto di Struttura della Materia, Consiglio Nazionale delle Ricerche - ISM, via Fosso del Cavaliere, 00133 Roma (Italy); Le Lay, G. [Aix-Marseille University, CNRS-CINaM, Campus de Luminy, Case 913, F-13288 Marseille Cedex 09 (France); Instituto di Struttura della Materia, Consiglio Nazionale delle Ricerche - ISM, via Fosso del Cavaliere, 00133 Roma (Italy)

    2014-01-13

    The epitaxial growth and the electrical resistance of multilayer silicene on the Ag(111) surface has been investigated. We show that the atomic structure of the first silicene layer differs from the next layers and that the adsorption of Si induces the formation of extended silicene terraces surrounded by step bunching. Thanks to the controlled contact formation between the tips of a multiple probe scanning tunneling microscope and these extended terraces, a low sheet resistance, albeit much higher than the electrical resistance of the underlying silver substrate, has been measured, advocating for the electrical viability of multilayer silicene.

  11. Reverse engineering of multi-layer films

    Directory of Open Access Journals (Sweden)

    Effendi Widjaja

    2011-03-01

    Full Text Available This contribution introduces the combined application of Raman microscopy and band-target entropy minimization (BTEM in order to successfully reverse-engineer a multi-layer packaging material. Three layers are identified, namely, polyethylene, a paper and talc layer (with two distinct cellulose forms, and a poly-styrene co-polymer composite containing anatase and calcite. This rapid and non-destructive approach provides a unique opportunity for the assessment of multi-layer composites, including the constitution of the additives present.

  12. Sperm DNA fragmentation, recurrent implantation failure and recurrent miscarriage

    Directory of Open Access Journals (Sweden)

    Carol Coughlan

    2015-01-01

    Full Text Available Evidence is increasing that the integrity of sperm DNA may also be related to implantation failure and recurrent miscarriage (RM. To investigate this, the sperm DNA fragmentation in partners of 35 women with recurrent implantation failure (RIF following in vitro fertilization, 16 women diagnosed with RM and seven recent fathers (control were examined. Sperm were examined pre- and post-density centrifugation by the sperm chromatin dispersion (SCD test and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL assay. There were no significant differences in the age of either partner or sperm concentration, motility or morphology between three groups. Moreover, there were no obvious differences in sperm DNA fragmentation measured by either test. However, whilst on average sperm DNA fragmentation in all groups was statistically lower in prepared sperm when measured by the SCD test, this was not seen with the results from the TUNEL assay. These results do not support the hypothesis that sperm DNA fragmentation is an important cause of RIF or RM, or that sperm DNA integrity testing has value in such patients. It also highlights significant differences between test methodologies and sperm preparation methods in interpreting the data from sperm DNA fragmentation tests.

  13. Transmission fingerprints in quasiperiodic magnonic multilayers

    International Nuclear Information System (INIS)

    In this paper we investigated the influence of mirror symmetry on the transmission spectra of quasiperiodic magnonic multilayers arranged according to Fibonacci, Thue-Morse and double period quasiperiodic sequences. We consider that the multilayers composed of two simple cubic Heisenberg ferromagnets with bulk exchange constants JA and JB and spin quantum numbers SA and SB, respectively. The multilayer structure is surrounded by two semi-infinite slabs of a third Heisenberg ferromagnetic material with exchange constant JC and spin quantum number SC. For simplicity, the lattice constant has the same value a in each material, corresponding to epitaxial growth at the interfaces. The transfer matrix treatment was used for the exchange-dominated regime, taking into account the random phase approximation (RPA). Our numerical results illustrate the effects of mirror symmetry on (i) transmission spectra and (ii) transmission fingerprints. - Highlights: → We model quasiperiodic magnetic multilayers presenting mirror symmetry. → We investigated the allowed and forbidden bands of magnonic transmission. → Transmission return maps show the influence of mirror symmetry. → Mirror symmetry has no effect on the Fibonacci case. → Mirror symmetry does have effect on the Thue-Morse and double period cases.

  14. Thermal Transport in Graphene and Graphene Multilayers

    OpenAIRE

    Balandin, Alexander A.; Denis L. Nika

    2015-01-01

    In this paper we review thermal properties of graphene and multilayer graphene and discuss the optothermal technique developed for the thermal conductivity measurements. We also outline different theoretical approaches used for the description of phonon transport in graphene and provide comparison with available experimental thermal conductivity data.

  15. Study of thermal conductivity of multilayer insulation

    International Nuclear Information System (INIS)

    This paper presents experimental determination of the apparent thermal conductivity of multilayer insulation for a cryogenic system. The variation of thermal conductivity with residual gas pressure is studied and the optimum vacuum for good insulating performance is determined. Evaporation loss technique for heat-inleak determination is employed. (author)

  16. Guided wave sensing of polyelectrolyte multilayers

    DEFF Research Database (Denmark)

    Horvath, R.; Pedersen, H.C.; Cuisinier, F.J.G.

    2006-01-01

    A planar optical waveguide configuration is proposed to monitor the buildup of thick polyelectrolyte multilayers on the surface of the waveguide in aqueous solutions. Instead of detecting the layer by the electromagnetic evanescent field the polyelectrolyte layer acts as an additional waveguiding...

  17. Coherent multilayer crystals and method of making

    International Nuclear Information System (INIS)

    A new material consisting of a multilayer crystalline structure which is coherent perpendicular to the layers and where each layer is composed of a single crystalline element. The individual layers may vary from 2A to 100A or more in thickness

  18. Multilayer radio absorbing nanocomposite materials and coatings

    International Nuclear Information System (INIS)

    Basic principles for design of multilayer film materials on the base of nanocomposite and chiral layers (NbC, Y2Fe5O12) have been developed. By changing of the structure, number, and order of alternation of the layers, absorption spectra of produced composite materials can be varied in the range of electromagnetic radiation 0.8-14.0 cm

  19. Multilayers gratings for X-UV optics

    International Nuclear Information System (INIS)

    Multilayer gratings are thin film structures possessing periodicities both in the normal and lateral directions. They combine the properties of surface gratings and planar multilayers thus providing a high throughput and high spectral resolution on higher diffraction orders. The unique diffraction properties are utilized in the X-ray and ultraviolet optics where no lenses or mirrors comparable with those for visible light are available. Multilayer gratings act as constant resolution dispersion elements in a broad spectral range. A fan of grating diffractions in real space is represented by a set of points on equidistant truncation rods in the reciprocal space. The kinematical theory of X-ray scattering explains well the positions of the grating truncation rods while the dynamical theory is inevitable to calculate the intensities along the truncation rods (grating efficiency). The properties of multilayer gratings are exemplified on two differently prepared lamellar gratings with the nominal normal and lateral periods of 8 nm and 800 nm, respectively. The fabrication steps are described in detail. The specular and non-specular X-ray reflectivities at wavelength 0.15418 nm were measured on one of the samples. The dynamical theory of X-ray scattering with a matrix modal eigenvalue approach was applied to extract the real structural parameters such as the surface and interface roughnesses, individual layer thicknesses, and the lamella width to the grating period ratio. The X-ray reflectometry is completed by microscopy observations which provide complementary and direct information on the local surface profile. (Authors)

  20. Reliable Communications Using Multi-layer Transmission

    Science.gov (United States)

    Assimi, Abdel-Nasser; Poulliat, Charly; Fijalkow, Inbar

    In this paper, we propose a MIMO approach for packet combining in hybrid automatic repeat request (HARQ) protocols using single-carrier multi-layer transmission over block fading channels. Based on this model, the problem of the optimization of the linear superposition coefficients is briefly addressed.

  1. Growth and structure of metallic multilayer system

    International Nuclear Information System (INIS)

    The multichamber ultrahigh vacuum system which has been built for surface and interface studies in thin magnetic films in the Institute of Nuclear Physics in Cracow has been performed. The design and performance of this setup, together with a description of other analytical techniques used for studying the structural and magnetotransport properties of thin multilayered systems has been presented

  2. Josephson plasma resonance in superconducting multilayers

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig

    We derive an analytical solution for the josephson plasma resonance of superconducting multilayers. This analytical solution is derived mainly for low T-c systems with magnetic coupling between the superconducting layers, but many features of our results are more general, and thus an application to...

  3. Josephson plasma resonance in superconducting multilayers

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Sakai, S

    1998-01-01

    We derive an analytical solution for the Josephson plasma resonance of superconducting multilayers. This analytical solution is derived mainly for low-T-c systems with magnetic coupling between the superconducting layers. but many features of our results are more general, and thus an application to...

  4. [Recurrent urological cancer--diagnose and treatment].

    Science.gov (United States)

    Takeshima, H; Akaza, H

    1998-02-01

    Clinical efforts to spare bladder function even in the case of muscle invasive recurrent bladder cancer is taking. Early detection of recurrence is essential for bladder sparing, and both urinary NMP22 and BTA are thought to have potency to detect recurrence of bladder cancer earlier than urinary cytology. Intravesical administration of BCG for superficial bladder cancer and intraarterial injection of chemoagents (Methotrexate and Cisplatin) with radiation for muscle invasive bladder cancer are thought to play important roles in sparing the bladder. Early detection of recurrent prostate cancer is becoming easier by ultrasensitive PSA assay. Though the value of early detection of recurrence is not proven since the benefits of early hormonal treatment have not yet been established, that should be a good indicator to evaluate new and coming treatments and play a important role to develop an effective treatment for recurrent prostate cancer. PMID:9492827

  5. Multilayer Reflectors for Soft X-Rays

    Science.gov (United States)

    Fernandez, Felix Eugenio

    1987-11-01

    Current technology has made possible the fabrication of multilayered optical elements for soft x-ray radiation. These structures find a variety of important applications. Difficulties in the design and fabrication of multilayers for soft x -rays are related to the lack of information about the properties of materials in the very thin layers (~ 5-100 A) required. Imperfections cause the measured optical properties of the multilayers to deviate strongly from ideal behavior. Realistic calculations of reflectance must take these imperfections into account. We review the pertinent theory, with attention to the problem of including non-ideal properties. We also review characterization techniques suitable for the measurement of relevant structural and stoichiometric parameters of the multilayer. A detailed characterization procedure is presented. This procedure is capable of accurately determining the layer thicknesses, material densities, interfacial rms roughness or diffusion values, crystalline structure, concentration of contaminants, and extent of surface oxidation. The techniques used included low-angle x-ray theta-2theta diffraction with parallel-beam and Bragg-Brentano geometries, wide-film Debye-Scherrer ("Read") camera and Seemann-Bohlin diffractometer, Rutherford backscattering spectroscopy, and transmission electron microscopy. Si/W multilayer mirrors were designed for normal -incidence 210 A radiation. Samples were fabricated using a magnetically-confined-plasma dc-triode sputtering technique. Our characterization procedure was applied to these samples. To our knowledge, this is the first time such a comprehensive set of characterization techniques has been applied to a multilayer x-ray optical element. The same samples were tested with synchrotron radiation over a wide spectral range, and for several incidence angles. The measured reflectance is in excellent agreement with curves calculated using the information obtained from the characterization results, with no adjustable parameters. The Si/W combination is shown to have good layering characteristics. The near -normal reflectance of the multilayers was 20 to 30 times better than the reflectivity of the best single-surface mirrors at the same wavelengths.

  6. Esophageal recurrence of medullary thyroid carcinoma

    OpenAIRE

    Muñoz de Nova, Jose Luis; Dworzynska, Agnieszka; Lorente-Poch, Leyre; Sancho, Juan Jose; Sitges-Serra, Antonio

    2015-01-01

    Medullary thyroid carcinoma (MTC) metastasizes to the regional lymph nodes and to the lungs, liver and bones. Only one case of recurrence of MTC involving the upper gastrointestinal tract has been reported so far. We describe the case of a 38-year-old woman with MTC, who developed an upper esophageal submucosal recurrence after two previous local recurrences treated surgically and one ethanol injection. After resection of the right lateral esophageal wall, calcitonin dropped by 60% and showed...

  7. Recurrence quantification analysis of chimera states

    Science.gov (United States)

    Santos, M. S.; Szezech, J. D.; Batista, A. M.; Caldas, I. L.; Viana, R. L.; Lopes, S. R.

    2015-10-01

    Chimera states, characterised by coexistence of coherence and incoherence in coupled dynamical systems, have been found in various physical systems, such as mechanical oscillator networks and Josephson-junction arrays. We used recurrence plots to provide graphical representations of recurrent patterns and identify chimera states. Moreover, we show that recurrence plots can be used as a diagnostic of chimera states and also to identify the chimera collapse.

  8. Interpersonal mechanisms in recurrence of depression

    OpenAIRE

    Bos, Elisabeth Henriëtte

    2005-01-01

    Depression is serious disease, also because of its recurrent nature. Many people who have become depressed once, will become depressed more often. Moreover, the risk of depression seems to increase with every further episode. These observations underline the importance of gaining a better understanding of the mechanisms behind recurrence of depression. The present multidisciplinary project investigates 5 different types of risk factors for recurrence of depression (factors from the fields of ...

  9. Recurrent, giant subcutaneous leiomyosarcoma of the thigh

    Directory of Open Access Journals (Sweden)

    Gao Chuanping, MD

    2015-10-01

    Full Text Available We present a case of recurrent, massive subcutaneous leiomyosarcoma involving the left thigh in a 29-year-old male from Madagascar. The patient had earlier undergone local resection of subcutaneous leiomyosarcoma a half year before. After surgical intervention, local recurrence developed at this site and was rapidly growing. The patient was surgically treated with a 2-cm-wide margin local excision in our hospital. The patient has remained recurrence free at 1-year follow-up.

  10. Recurrent IVF failure and hereditary thrombophilia

    OpenAIRE

    Leila Safdarian; Zahra Najmi; Ashraf Aleyasin; Marzieh Aghahosseini; Mandana Rashidi; Sara Asadollah

    2014-01-01

    Background: The largest percentage of failed invitro fertilization (IVF) cycles, are due to lack of implantation. As hereditary thrombophilia can cause in placentation failure, it may have a role in recurrent IVF failure. Objective: Aim of this case-control study was to determine whether hereditary thrombophilia is more prevalent in women with recurrent IVF failures. Materials and Methods: Case group comprised 96 infertile women, with a history of recurrent IVF failure. Control gr...

  11. Diffraction gratings based on asymmetric-cut multilayers

    Science.gov (United States)

    Prasciolu, Mauro; Chapman, Henry N.; Bajt, Saša.

    2015-05-01

    We report on the fabrication of novel diffraction gratings for soft x-ray and extreme ultra-violet (EUV) photon energies based on asymmetric-cut multilayer structures. Asymmetric-cut multilayers are highly dispersive and highly efficient gratings obtained by slicing a thick multilayer coating. Multilayer deposition techniques enable sub-ångström precision in layer thickness control, which leads to close to perfect blazed gratings. However, the final grating size is limited by the maximum multilayer thickness for which one can still control the layer thickness, stress and roughness. Here, we present a new approach in which we substantially extend the grating size by combining specially prepared substrates, thick multilayer deposition and final polishing. Gratings prepared by this method, like asymmetric multilayers deposited on plane substrates, are highly dispersive and efficient. Their extended size make them ideal for use in monochromators, spectrometers and pulse compressors.

  12. Recurrence and Relapse in Bipolar Mood Disorder

    Directory of Open Access Journals (Sweden)

    S Gh Mousavi

    2004-06-01

    Full Text Available Background: Despite the effectiveness of pharmacotherapy in acute phase of bipolar mood disorder, patients often experience relapses or recurrent episodes. Hospitalization of patients need a great deal of financial and humanistic resources which can be saved through understanding more about the rate of relapse and factors affecting this rate. Methods: In a descriptive analytical study, 380 patients with bipolar disorder who were hospitalized in psychiatric emergency ward of Noor hospital, Isfahan, Iran, were followed. Each patient was considered for; the frequency of relapse and recurrence, kind of pharmachotherapy, presence of psychotherapeutic treatments, frequency of visits by psychiatrist and the rank of present episode. Results: The overall prevalence of recurrence was 42.2%. Recurrence was lower in patients using lithium carbonate or sodium valproate or combined therapy (about 40%, compared to those using carbamazepine (80%. Recurrence was higher in patients treated with only pharmacotherapy (44.5% compared to those treated with both pharmacotherapy and psychotherapy (22.2%. Patients who were visited monthy by psychiatrist had lower rate of recurrence compared to those who had irregular visits. Conclusion: The higher rate of recurrence observed in carbamazepine therapy may be due to its adverse reactions and consequently poor compliance to this drug. Lower rates of recurrence with psychotherapy and regular visits may be related to the preventive effects of these procedures and especially to the effective management of stress. Keywords: Bipolar Mood Disorder, Recurrence, Relapse.

  13. Recurrent odontogenic keratocyst within the masticatory space

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Su Yeon; Huh, Kyung Hoe; Yi, Won Jin; Choi, Hyun Bae; Choi, Soon Chul [School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    2008-06-15

    The odontogenic keratocyst (OKC) is a developmental odontogenic cyst typically occurring in the jaws. Since the first description of OKC was published in 1956, the lesion has been of particular interest because of its specific histopathologic features, high recurrence rate, and aggressive behavior. Recurrences most commonly arise within bone at the site of the original cyst. However, as lining cells may find their way into surrounding tissues either from implantation during surgery or from cortical perforation recurrences may arise at a distance from the original cyst. Here, we report a rare case of recurrent OKC which was first developed in mandible and recurred within the masticatory space.

  14. Palbociclib Isethionate in Treating Younger Patients With Recurrent, Progressive, or Refractory Central Nervous System Tumors

    Science.gov (United States)

    2015-10-19

    Childhood Choroid Plexus Tumor; Childhood Ependymoblastoma; Childhood Grade III Meningioma; Childhood High-grade Cerebellar Astrocytoma; Childhood High-grade Cerebral Astrocytoma; Childhood Medulloepithelioma; Recurrent Childhood Anaplastic Astrocytoma; Recurrent Childhood Anaplastic Oligoastrocytoma; Recurrent Childhood Anaplastic Oligodendroglioma; Recurrent Childhood Brain Stem Glioma; Recurrent Childhood Cerebellar Astrocytoma; Recurrent Childhood Cerebral Astrocytoma; Recurrent Childhood Giant Cell Glioblastoma; Recurrent Childhood Glioblastoma; Recurrent Childhood Gliomatosis Cerebri; Recurrent Childhood Gliosarcoma; Recurrent Childhood Medulloblastoma; Recurrent Childhood Pineoblastoma; Recurrent Childhood Supratentorial Primitive Neuroectodermal Tumor

  15. Recurrent pregnancy loss and obesity.

    Science.gov (United States)

    Sugiura-Ogasawara, Mayumi

    2015-05-01

    Recurrent pregnancy loss (RPL) was defined as two or more miscarriages. Antiphospholipid syndrome, uterine anomalies, and parental chromosomal abnormalities, particularly translocation and abnormal embryonic karyotype, are identifiable causes of RPL. Obesity may increase the risk of sporadic miscarriage in pregnancies conceived spontaneously. Obesity with body mass index (BMI)>30 kg/m2 is an independent risk factor for further miscarriage with odds ratio 1.7-3.5 in patients with early RPL. Obesity is associated with euploid miscarriage. Unexplained RPL with euploid embryo might be a common disease caused by both polymorphisms of multiple susceptibility genes and lifestyle factors such as women's age, obesity, and smoking. Patients with a history of RPL were found to have a higher risk of cardiovascular disease, celiac disease, gastric ulcer, gastritis, and atopic dermatitis. No study has examined the effect of weight loss on the prevention of further miscarriage in patients with RPL. PMID:25589398

  16. Atypical recurrence of rheumatic chorea

    Directory of Open Access Journals (Sweden)

    Gunjan Pankaj Kumar

    2015-05-01

    Full Text Available Syndenhams Chorea in acute rheumatic fever is reported to occur in 20-30% of patients. It is usually late onset, occurring upto 6 months after acute infection but may occasionally be present as presenting symptom of rheumatic fever. It is a self-limiting condition with spontaneous remission lasting from 1 week to 6 months. The risk of recurrence is present in 1st 1-2 years in about 20% of cases. Most of children (two thirds with rheumatic fever are of school age (5-15 years of age. It is common in India and the incidence has not shown the declining trends seen in the developing countries. We report the clinical findings, investigations and the course of clinical development of a 14-year-old girl, who presented with Rheumatic chorea which recurred 3 years after the initial episode. [Int J Res Med Sci 2015; 3(5.000: 1272-1273

  17. Recurrent Glioblastoma: Where we stand

    Directory of Open Access Journals (Sweden)

    Sanjoy Roy

    2015-01-01

    Full Text Available Current first-line treatment regimens combine surgical resection and chemoradiation for Glioblastoma that provides a slight increase in overall survival. Age on its own should not be used as an exclusion criterion of glioblastoma multiforme (GBM treatment, but performance should be factored heavily into the decision-making process for treatment planning. Despite aggressive initial treatment, most patients develop recurrent diseases which can be treated with re-resection, systemic treatment with targeted agents or cytotoxic chemotherapy, reirradiation, or radiosurgery. Research into novel therapies is investigating alternative temozolomide regimens, convection-enhanced delivery, immunotherapy, gene therapy, antiangiogenic agents, poly ADP ribose polymerase inhibitors, or cancer stem cell signaling pathways. Given the aggressive and resilient nature of GBM, continued efforts to better understand GBM pathophysiology are required to discover novel targets for future therapy.

  18. Modelling recurrent malaria in Thailand.

    Science.gov (United States)

    Tiensuwan, M

    2000-06-01

    Malaria is a common infectious disease in many tropical countries. Thailand is located geographically in the tropical zone and the transmission of malaria is found widely, for instance, in the Tak province. The objective of this study is to find risk factors for the number of experiences with malaria of malaria patients, i.e. repeated recurrences of the disease within an infected individual in the Tak province in the rainy season by using Poisson regression models. Among the models fitted, the best are chosen based on the analysis of deviance. The results of this study show that the risk factors are race, spraying insecticides in houses in an infectious area, number of days staying overnight without protection against mosquitoes of malaria patients, and whether or not any members of the family of the malaria patient have had malaria. PMID:11084707

  19. Chronic recurrent multifocal osteomyelitis (CRMO)

    International Nuclear Information System (INIS)

    Chronic recurrent multifocal osteomyelitis (CRMO) is an unusual clinical entity. More than 200 cases are described in the literature and it is presented here with special reference to its radiological aspects. It is an acquired disease of the skeleton which occurs predominantly during childhood and adolescence. About ten per cent of cases begin in early or, rarely, in later adult life. This variant is described here for the first time and is discussed as 'adult CRMO'. The underlying pathology is a bland, predominantly lympho-plasma cellular osteomyelitis which is self-limiting and leads to bone sclerosis (Garre). It probably involves an abnormal immune process which follows an infection but remains clinically latent and remains aseptic and sterile. In a quarter of cases there is an association with pustulosis palmo-plantaris and its relationship with psoriatic arthropathy is discussed. The clinical, histopathological and imaging features (radiological and particularly MRT) and the bone changes are described. (orig./AJ)

  20. Pharmacotherapy of recurrent aphthous ulcers

    Directory of Open Access Journals (Sweden)

    J P Angeline Archana

    2011-01-01

    Full Text Available Aphthous ulcer is the most common type of ulcer affecting the oral cavity and is considered to be one of the most painful conditions. Treatment is often unsatisfactory. Newer treatment modalities are therefore being tried. Amlexanox and rebamipide are the approved drugs for painful aphthous ulcers and have been used in painful symptoms of acid peptic disease as prostaglandin enhancers. Safety and efficacy of the drugs used in the treatment of recurrent aphthous ulcers were evaluated and being used widely by most of the treating physicians choosing a modality of treatment of their experience. There is no proper treatment modality available till date. Various drugs and their efficacy with least adverse drug effects while treating the various aphthous ulcers are discussed.

  1. Recurrent Primary Spinal Hydatid Cyst

    Directory of Open Access Journals (Sweden)

    Okan Turk

    2015-03-01

    Full Text Available Primary hydatid disease of spine is rare and spinal hydatitosis constitute only 1% of all hydatitosis. We report a case of recurrent primary intraspinal extradural hydatid cyst of the thoracic region causing progressive paraparesis. The patient was operated 16 years ago for primary spinal hydatid disease involvement and was instrumented dorsally for stabilization. The magnetic resonance imaging (MRI of thoracic spine showed a cystic lesion at T11-12 level and compressed spinal cord posterolaterally. Intraspinal cyst was excised through T11-12 laminectomy which made formerly. The early postoperative period showed a progressive improvement of his neurological deficit and he was discharged with antihelmintic treatment consisting of albendazole and amoxicillin-sulbactam combination. [Cukurova Med J 2015; 40(Suppl 1: 84-89

  2. Polyelectrolyte multilayers: An odyssey through interdisciplinary science

    Science.gov (United States)

    Jaber, Jad A.

    This dissertation provides an overview of a self assembled multilayer technique based on the alternating deposition of oppositely charged polyelectrolytes onto charged solid supports. The basic principles and methodologies governing this technique are laid down, and new strategies are built upon the latter, in an effort to develop innovative technologies that would be beneficial for making new products or improving the quality of existing ones. Fundamental studies to characterize the water content, efficiency of ion-pairing, differential strength of electrostatic interactions, topology, and viscoelastic properties of polyelectrolyte multilayers, PEMUs, are illustrated and conducted. In addition, polyelectrolyte multilayers that are stimulus responsive, or support active and controlled bio-motor protein interactions are described. Attenuated total reflectance Fourier transform infrared, (ATR), spectroscopy was used to compare the extent of swelling and doping within PAH/PSS and PDADMA/PSS polyelectrolyte multilayers. Unlike PDADMA/PSS, whose water content depended on the solution ionic strength, PAH/PSS was resistant to swelling by salt. It was stable up to 4.0 M sodium chloride, with 6 water molecules per ion-pair. Using the infrared active perchlorate sodium salt, the amount of residual persistent extrinsic sites in both PDADMA/PSS and PAH/PSS was determined to be 3% and 6%, respectively. The free energy of association between the polymer segments, in the presence of sodium perchlorate, was in the order of 4.5 kJ mol-1 and -9.5 kJ mol-1 for PDADMA/PSS and PAH/PSS correspondingly. Thus, indicating the relatively strong electrostatic association between the polymer segments in a PAH/PSS relative to PDADMA/PSS multilayer. Adjusting the pH of the solution in contact with the PAH/PSS multilayer to 11.5 resulted in a first order discontinuous dissociation of the Pol+Pol- bonds. Techniques used to study the mechanical properties of single muscle fiber were adapted to characterize the topology, viscoelastic behavior, complex modulus and loss factor of PDADMA/PSS multilayers, over a range of frequencies and strain amplitudes. Tensile mode (transient uniaxial stretching) of a PEMU microcoupon using a capacitative-type force transducer located on a modified stage of inverted microscope revealed evidence on the viscous-like behavior of polymer chains within PEMU. Dependence of viscosity was primarily on the ionic strength of the bathing solution, with appreciable stress relaxation occurring at high salt concentrations. Dynamic mechanical analysis was then used to determine the damping properties of PEMU where the length was oscillated sinusoidally, and the resulting force, amplitude and phase shift were observed. Compared to other commercially available polymer damping materials such as acrylic and rubber adhesives, PEMU demonstrated up to 250% enhancement in damping properties over the frequency range of 0.3-10 Hz. This was obtained while the multilayer dry thickness was 3000% less then that of the conventional adhesives. The synthesis of charged copolymers of poly(N-isopropylacrylamide), (PNIPAM), and their use in constructing thermally responsive PEMU were demonstrated. The temperature dependent water content of the thin film, studied in situ using ATR-FTIR spectroscopy, revealed microscopic and macroscopic transitions at 33 and 45C, respectively. About 7 water molecules per NIPAM repeat unit were found to be reversibly lost from, or recovered by, the film upon cycling over a temperature range of 10 to 55C. Assuming that each ion-pair represents a crosslink, swelling theory was used to translate these results into polymer-solvent interaction parameters and enthalpies of mixing for the various polymer components. In addition, the flux of a charged probe molecule, potassium ferricyanide, through the NIPAM-rich multilayer was assessed with rotating disk electrode voltammetry. Thermally reversible modulation of ion transport was demonstrated. Positive polyelectrolytes were investigated as new surface coatings for promoting in vi

  3. Preventing Relapse/Recurrence in Recurrent Depression With Cognitive Therapy: A Randomized Controlled Trial

    Science.gov (United States)

    Bockting, Claudi L. H.; Schene, Aart H.; Spinhoven, Philip; Koeter, Maarten W. J.; Wouters, Luuk F.; Huyser, Jochanan; Kamphuis, Jan H.

    2005-01-01

    This article reports on the outcome of a randomized controlled trial of cognitive group therapy (CT) to prevent relapse/recurrence in a group of high-risk patients diagnosed with recurrent depression. Recurrently depressed patients (N = 187) currently in remission following various types of treatment were randomized to treatment as usual,…

  4. Design and development of multilayer vascular graft

    Science.gov (United States)

    Madhavan, Krishna

    2011-07-01

    Vascular graft is a widely-used medical device for the treatment of vascular diseases such as atherosclerosis and aneurysm as well as for the use of vascular access and pediatric shunt, which are major causes of mortality and morbidity in this world. Dysfunction of vascular grafts often occurs, particularly for grafts with diameter less than 6mm, and is associated with the design of graft materials. Mechanical strength, compliance, permeability, endothelialization and availability are issues of most concern for vascular graft materials. To address these issues, we have designed a biodegradable, compliant graft made of hybrid multilayer by combining an intimal equivalent, electrospun heparin-impregnated poly-epsilon-caprolactone nanofibers, with a medial equivalent, a crosslinked collagen-chitosan-based gel scaffold. The intimal equivalent is designed to build mechanical strength and stability suitable for in vivo grafting and to prevent thrombosis. The medial equivalent is designed to serve as a scaffold for the activity of the smooth muscle cells important for vascular healing and regeneration. Our results have shown that genipin is a biocompatible crosslinker to enhance the mechanical properties of collagen-chitosan based scaffolds, and the degradation time and the activity of smooth muscle cells in the scaffold can be modulated by the crosslinking degree. For vascular grafting and regeneration in vivo, an important design parameter of the hybrid multilayer is the interface adhesion between the intimal and medial equivalents. With diametrically opposite affinities to water, delamination of the two layers occurs. Physical or chemical modification techniques were thus used to enhance the adhesion. Microscopic examination and graft-relevant functional characterizations have been performed to evaluate these techniques. Results from characterization of microstructure and functional properties, including burst strength, compliance, water permeability and suture strength, showed that the multilayer graft possessed properties mimicking those of native vessels. Achieving these FDA-required functional properties is essential because they play critical roles in graft performances in vivo such as thrombus formation, occlusion, healing, and bleeding. In addition, cell studies and animal studies have been performed on the multilayer graft. Our results show that the multilayer graft support mimetic vascular culture of cells and the acellular graft serves as an artery equivalent in vivo to sustain the physiological conditions and promote appropriate cellular activity. In conclusion, the newly-developed hybrid multilayer graft provides a proper balance of biomechanical and biochemical properties and demonstrates the potential for the use of vascular tissue engineering and regeneration.

  5. Recurrence in Major Depression: A Conceptual Analysis

    Science.gov (United States)

    Monroe, Scott M.; Harkness, Kate L.

    2011-01-01

    Theory and research on major depression have increasingly assumed a recurrent and chronic disease model. Yet not all people who become depressed suffer recurrences, suggesting that depression is also an acute, time-limited condition. However, few if any risk indicators are available to forecast which of the initially depressed will or will not…

  6. Recurrent hypersomnia: a review of 339 cases.

    Science.gov (United States)

    Billiard, Michel; Jaussent, Isabelle; Dauvilliers, Yves; Besset, Alain

    2011-08-01

    Based on 339 cases this review identifies, quantifies and compares 4 clinical forms of recurrent hypersomnia (1) Kleine-Levin syndrome (KLS) (239 cases), (2) Kleine-Levin syndrome without compulsive eating (KLS WOCE) (54 cases), (3) Menstrual related hypersomnia (MRH) (18 cases) and Recurrent hypersomnia with comorbidity (RHC) (28 cases). A second part of the review considers the main current issues on recurrent hypersomnia: the predisposing factors, including a window on family cases; the pathophysiology based on clinical patterns, neuroimaging data, neuropathological examinations and cerebrospinal fluid (CSF) hypocretin-1 measurements; the issues of recurrence and of a possible disruption of the circadian timing system; the relationships between recurrent hypersomnia and mood disorders; and a note on the atypical Kleine-Levin syndrome. The main outcomes of this study are a clear nosologic distinction of the different forms of recurrent hypersomnia, the finding that the prevalence of familial cases of KLS is in the same range as in narcolepsy, the suggestion of the possible involvement of a large set of cortical and subcortical structures in recurrent hypersomnia and some clues in favour of a relationship between recurrent hypersomnia and mood disorders. PMID:20970360

  7. Risk factors of recurrent anal sphincter ruptures

    DEFF Research Database (Denmark)

    Jangö, Hanna; Langhoff-Roos, J; Rosthøj, Steen; Sakse, A

    2012-01-01

    augmentation, epidural, episiotomy, vacuum extraction, forceps, shoulder dystocia, delivery interval and year of second delivery. Results  Out of 159 446 women, 7336 (4.6%) experienced an ASR at first delivery, and 521 (7.1%) had a recurrent ASR (OR 5.91). The risk factors of recurrent ASR in the multivariate...

  8. Forequarter amputation for recurrent breast cancer

    Directory of Open Access Journals (Sweden)

    Krishna N. Pundi

    2015-01-01

    Conclusion: Forequarter amputation can be judiciously used for patients with recurrent or metastatic breast cancer. Patients with recurrent disease without evidence of distant metastases may be considered for curative amputation, while others may receive palliative benefit; disappointingly our patient achieved neither of these outcomes. In the long term, these patients may still have significant psychological problems.

  9. Event dependent sampling of recurrent events

    DEFF Research Database (Denmark)

    Kvist, Tine Kajsa; Andersen, Per Kragh; Angst, Jules; Kessing, Lars Vedel

    2010-01-01

    The effect of event-dependent sampling of processes consisting of recurrent events is investigated when analyzing whether the risk of recurrence increases with event count. We study the situation where processes are selected for study if an event occurs in a certain selection interval. Motivation...

  10. Cross recurrence quantification of coupled oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Shockley, Kevin; Butwill, Matthew; Zbilut, Joseph P.; Webber, Charles L

    2002-11-25

    Subtle nonlinear behaviors of fluid-coupled mechanical oscillators at low and medium viscosities were better detected by cross recurrence analysis than spectral analysis. Cross recurrence with its high sensitivity to nonlinear dynamics may have applicability to weakly coupled oscillators prevalent in biology and physiology.

  11. Cross recurrence quantification of coupled oscillators

    Science.gov (United States)

    Shockley, Kevin; Butwill, Matthew; Zbilut, Joseph P.; Webber, Charles L.

    2002-11-01

    Subtle nonlinear behaviors of fluid-coupled mechanical oscillators at low and medium viscosities were better detected by cross recurrence analysis than spectral analysis. Cross recurrence with its high sensitivity to nonlinear dynamics may have applicability to weakly coupled oscillators prevalent in biology and physiology.

  12. Decomposable spaces of recurrent conformal curvature

    International Nuclear Information System (INIS)

    Definitions of a decomposable space, decomposition spaces and a space of recurrent conformal curvature are given. A decomposable space of recurrent conformal curvature Vn, (shortly CKn) is looked upon as decomposition spaces Vr and Vn-r. With this concept some results on decomposable CKn are derived. (author). 5 refs

  13. ACQUIRED CUTIS LAXA WITH RECURRENT URTICARIA

    Directory of Open Access Journals (Sweden)

    Ganaparthi

    2015-05-01

    Full Text Available A 30 year old male patient presented with progressive laxity and wrinkling of skin over the face for past 10 years, patient also gives history of recurrent urticaria since 12 years. Skin biopsy using Verhoff Van Gieson stain suggestive of cutis laxa. We are reporting a rare case of acquired cutis laxa with recurrent urticaria

  14. Local Recurrence After Uveal Melanoma Proton Beam Therapy: Recurrence Types and Prognostic Consequences

    Energy Technology Data Exchange (ETDEWEB)

    Caujolle, Jean-Pierre, E-mail: ncaujolle@aol.com [Department of Ophthalmology, Saint Roch Hospital, Nice Teaching Hospital, Nice (France); Paoli, Vincent [Department of Ophthalmology, Saint Roch Hospital, Nice Teaching Hospital, Nice (France); Chamorey, Emmanuel [Department of Radiation Oncology, Protontherapy Center, Centre Antoine Lacassagne, Nice (France); Department of Biostatistics and Epidemiology, Centre Antoine Lacassagne, Nice (France); Maschi, Celia; Baillif, Stéphanie [Department of Ophthalmology, Saint Roch Hospital, Nice Teaching Hospital, Nice (France); Herault, Joël [Department of Radiation Oncology, Protontherapy Center, Centre Antoine Lacassagne, Nice (France); Gastaud, Pierre [Department of Ophthalmology, Saint Roch Hospital, Nice Teaching Hospital, Nice (France); Hannoun-Levi, Jean Michel [Department of Radiation Oncology, Protontherapy Center, Centre Antoine Lacassagne, Nice (France)

    2013-04-01

    Purpose: To study the prognosis of the different types of uveal melanoma recurrences treated by proton beam therapy (PBT). Methods and Materials: This retrospective study analyzed 61 cases of uveal melanoma local recurrences on a total of 1102 patients treated by PBT between June 1991 and December 2010. Survival rates have been determined by using Kaplan-Meier curves. Prognostic factors have been evaluated by using log-rank test or Cox model. Results: Our local recurrence rate was 6.1% at 5 years. These recurrences were divided into 25 patients with marginal recurrences, 18 global recurrences, 12 distant recurrences, and 6 extrascleral extensions. Five factors have been identified as statistically significant risk factors of local recurrence in the univariate analysis: large tumoral diameter, small tumoral volume, low ratio of tumoral volume over eyeball volume, iris root involvement, and safety margin inferior to 1 mm. In the local recurrence-free population, the overall survival rate was 68.7% at 10 years and the specific survival rate was 83.6% at 10 years. In the local recurrence population, the overall survival rate was 43.1% at 10 years and the specific survival rate was 55% at 10 years. The multivariate analysis of death risk factors has shown a better prognosis for marginal recurrences. Conclusion: Survival rate of marginal recurrences is superior to that of the other recurrences. The type of recurrence is a clinical prognostic value to take into account. The influence of local recurrence retreatment by proton beam therapy should be evaluated by novel studies.

  15. Local Recurrence After Uveal Melanoma Proton Beam Therapy: Recurrence Types and Prognostic Consequences

    International Nuclear Information System (INIS)

    Purpose: To study the prognosis of the different types of uveal melanoma recurrences treated by proton beam therapy (PBT). Methods and Materials: This retrospective study analyzed 61 cases of uveal melanoma local recurrences on a total of 1102 patients treated by PBT between June 1991 and December 2010. Survival rates have been determined by using Kaplan-Meier curves. Prognostic factors have been evaluated by using log-rank test or Cox model. Results: Our local recurrence rate was 6.1% at 5 years. These recurrences were divided into 25 patients with marginal recurrences, 18 global recurrences, 12 distant recurrences, and 6 extrascleral extensions. Five factors have been identified as statistically significant risk factors of local recurrence in the univariate analysis: large tumoral diameter, small tumoral volume, low ratio of tumoral volume over eyeball volume, iris root involvement, and safety margin inferior to 1 mm. In the local recurrence-free population, the overall survival rate was 68.7% at 10 years and the specific survival rate was 83.6% at 10 years. In the local recurrence population, the overall survival rate was 43.1% at 10 years and the specific survival rate was 55% at 10 years. The multivariate analysis of death risk factors has shown a better prognosis for marginal recurrences. Conclusion: Survival rate of marginal recurrences is superior to that of the other recurrences. The type of recurrence is a clinical prognostic value to take into account. The influence of local recurrence retreatment by proton beam therapy should be evaluated by novel studies

  16. Calcaneal chondroblastoma with pathologic fracture and recurrence.

    Science.gov (United States)

    Dutt, Laksha; Schade, Valerie L; Manoso, Mark W

    2015-01-01

    Chondroblastomas account for 80% of cases. Local recurrence rates of ≤38% have been reported, most often because of inadequate resection, and have been associated with malignant conversion and metastasis. Adjuvant therapies can help minimize the incidence of local recurrence. Long-term follow-up examinations are recommended, given the protracted interval that can exist between recurrence and the potential for malignant conversion and metastasis. We present the case of a young, healthy, active male with a calcaneal chondroblastoma and associated pathologic fracture whose initial treatment consisted of curettage, hydrogen peroxide lavage, and allogeneic bone grafting. Recurrence developed at 15 months postoperatively and was treated with repeat curettage, high-speed burring, and reconstruction with steel Steinman pins and polymethylmethacrylate, resulting in no pain or recurrence at the 5-month follow-up point. PMID:25624038

  17. MRI diagnosis of recurrence of gynaecological tumours

    International Nuclear Information System (INIS)

    Because of the differences in the signals from recurrent tumours and fibrosis during MRT, this method is highly suitable for differentiating between recurrent gynaecological tumours and scar formation. The value of MRT in investigating suspected recurrences was studied in 27 patients aged between 34 and 83 years. It was possible to distinguish between recurrent tumour with its high intensity signal from low signal fibrosis, using T2-weighted spin echo sequences in all cases. By means of multiplanar reconstruction and because of its high soft tissue contrast it was possible to determine the extent of tumour growth and differentiate it from surrounding tissues. With a sensitivity of 90%, specificity of 100% and accuracy of 92%, MRT is superior to all other imaging methods, including CT, in the diagnosis of tumour recurrence. (orig.)

  18. Mathematical Formulation of Multi-Layer Networks

    CERN Document Server

    De Domenico, Manlio; Cozzo, Emanuele; Kivelä, Mikko; Moreno, Yamir; Porter, Mason A; Gòmez, Sergio; Arenas, Alex

    2013-01-01

    A network representation is useful for describing the structure of a large variety of complex systems. However, most real and engineered systems have multiple subsystems and layers of connectivity, and the data produced by such systems is very rich. Achieving a deep understanding of such systems necessitates generalizing "traditional" network theory, and the newfound deluge of data now makes it possible to test increasingly general frameworks for the study of networks. In particular, although adjacency matrices are useful to describe traditional single-layer networks, such a representation is insufficient for the analysis and description of multiplex and time-dependent networks. One must therefore develop a more general mathematical framework to cope with the challenges posed by multi-layer complex systems. In this paper, we introduce a tensorial framework to study multi-layer networks, and we discuss the generalization of several important network descriptors and dynamical processes ---including degree centr...

  19. Multiple wavelength photolithography for preparing multilayer microstructures

    Science.gov (United States)

    Dentinger, Paul Michael (Livermore, CA); Krafcik, Karen Lee (Livermore, CA)

    2003-06-24

    The invention relates to a multilayer microstructure and a method for preparing thereof. The method involves first applying a first photodefinable composition having a first exposure wavelength on a substrate to form a first polymeric layer. A portion of the first photodefinable composition is then exposed to electromagnetic radiation of the first exposure wavelength to form a first pattern in the first polymeric layer. After exposing the first polymeric layer, a second photodefinable composition having a second exposure wavelength is applied on the first polymeric layer to form a second polymeric layer. A portion of the second photodefinable composition is then exposed to electromagnetic radiation of the second exposure wavelength to form a second pattern in the second polymeric layer. In addition, a portion of each layer is removed according to the patterns to form a multilayer microstructure having a cavity having a shape that corresponds to the portions removed.

  20. Thermal stability of Co/C multilayers

    International Nuclear Information System (INIS)

    The structural and interface changes induced by thermal annealing in Co/C multilayers were investigated. Co/C multilayers with period thickness of 4.1 nm and bi-layer number of 20 were deposited by direct current magnetron sputtering. We characterized all samples by using x-ray reflectivity, x-ray diffuse scattering, zero-field nuclear magnetic resonance spectroscopy and x-ray diffraction. The results indicate that Co and C atoms mixed during deposition and then after annealing both atoms separated from their mixed region. The annealing process also causes a sharp increase of roughness at interfaces, which can be attributed to the crystallization of Co layers. (paper)

  1. Magnetic studies in Fe/Zn multilayers

    International Nuclear Information System (INIS)

    The structural and magnetic properties of Fe/Zn films prepared by thermal evaporation have been studied by means of X-ray diffraction, vibrating-sample magnetometry and ferromagnetic resonance (FMR). For Fe layer thickness smaller than 20 A the saturation magnetization decreases with decreasing Fe thickness, which is an indication of the island growth of Zn and Fe-Zn interdiffusion at the layer interfaces. The effective field magnetization 4πMeff of the Fe/Zn multilayers was determined from the FMR data in a rotating external magnetic field. The interface anisotropy constant of the Fe/Zn multilayers, KS, is found to be 1.0 erg/cm2 at 300 K. This indicates the presence of a large perpendicular interface anisotropy and this may suggest that the largest part of KS originates from lattice misfit strain

  2. Random walk centrality in interconnected multilayer networks

    CERN Document Server

    Solé-Ribalta, Albert; Gómez, Sergio; Arenas, Alex

    2015-01-01

    Real-world complex systems exhibit multiple levels of relationships. In many cases they require to be modeled as interconnected multilayer networks, characterizing interactions of several types simultaneously. It is of crucial importance in many fields, from economics to biology and from urban planning to social sciences, to identify the most (or the less) influential nodes in a network using centrality measures. However, defining the centrality of actors in interconnected complex networks is not trivial. In this paper, we rely on the tensorial formalism recently proposed to characterize and investigate this kind of complex topologies, and extend two well known random walk centrality measures, the random walk betweenness and closeness centrality, to interconnected multilayer networks. For each of the measures we provide analytical expressions that completely agree with numerically results.

  3. Optics in magnetic multilayers and nanostructures

    CERN Document Server

    Visnovsky, Stefan

    2006-01-01

    In the continuing push toward optical computing, the focus remains on finding and developing the right materials. Characterizing materials, understanding the behavior of light in these materials, and being able to control the light are key players in the search for suitable optical materials. Optics in Magnetic Multilayers and Nanostructures presents an accessible introduction to optics in anisotropic magnetic media.While most of the literature presents only final results of the complicated formulae for the optics in anisotropic media, this book provides detailed explanations and full step-by-step derivations that offer insight into the procedure and reveal any approximations. Based on more than three decades of experimental research on the subject, the author explains the basic concepts of magnetooptics; nonreciprocal wave propagation; the simultaneous effect of crystalline symmetry and arbitrarily oriented magnetization on the form of permittivity tensors; spectral dependence of permittivity; multilayers at...

  4. Patterning of EUVL binary etched multilayer mask

    Science.gov (United States)

    Takai, Kosuke; Motokawa, Takeharu; Murano, Koji; Kamo, Takashi; Hayashi, Naoya

    2013-09-01

    Recently, development of next generation extremely ultraviolet lithography (EUVL) equipment with high-NA (Numerical Aperture) optics for less than hp10nm node is accelerated. While studying more than 0.45 NA, incident angle distribution of EUV light irradiation to mask becomes larger. It induces degradation of exposure margin to form horizontal line pattern (perpendicular to EUV light direction) because of large mask 3D effect. In order to resolve this issue, we evaluate binary etched multilayer mask structure, unlike conventional stacked absorber structure. As a result of improvement of binary etched multilayer mask process, hp40nm line and space pattern on mask (hp10nm on wafer using 4X optics) is demonstrated. This result suggests the capability of high-NA EUVL with 6inch and 4X optics with new mask structure.

  5. Information Propagation in Clustered Multilayer Networks

    CERN Document Server

    Zhuang, Yong

    2015-01-01

    In today's world, individuals interact with each other in more complicated patterns than ever. Some individuals engage through online social networks (e.g., Facebook, Twitter), while some communicate only through conventional ways (e.g., face-to-face). Therefore, understanding the dynamics of information propagation among humans calls for a multi-layer network model where an online social network is conjoined with a physical network. In this work, we initiate a study of information diffusion in a clustered multi-layer network model, where all constituent layers are random networks with high clustering. We assume that information propagates according to the SIR model and with different information transmissibility across the networks. We give results for the conditions, probability, and size of information epidemics, i.e., cases where information starts from a single individual and reaches a positive fraction of the population. We show that increasing the level of clustering in either one of the layers increas...

  6. Thermal performance of multilayer insulation. Part 3

    International Nuclear Information System (INIS)

    The effects of various parameters on heat flux between room temperature and liquid nitrogen temperature through multilayer insulation (MLI) are examined using prediction equations and experimental results. The investigated parameters were the following: the winding method of multilayer insulation, hot boundary temperature, mesh size of the net, number of layers of net inserted between films, direction of layer installation, film thickness, and use of single- vs. double-aluminized films. To accomplish good thermal performance, laminated winding, larger mesh size, a layer of net inserted between films, thinner film (light weight), and double-aluminized film are needed. The optimum number of layers for different parameters is also discussed. It is found that the optimum number of layers is in the range of 30 to 60 layers in many cases

  7. Magnetic nanodiscs fabricated from multilayered nanowires.

    Science.gov (United States)

    Min, Ji Hyun; Cho, Ji Ung; An, Boo Hyun; Choi, Daniel S; Kimlr, Young Keun

    2014-10-01

    We report a simple, high throughput synthesis method of producing magnetic nanodiscs, in which the diameter and thickness are easily controlled. This method consists of two steps: (1) Electrodeposition for growing multilayered nanowires and (2) Selective etching of sacrificial layers. The electrodeposition step results in a bundle of multilayered nanowires. The nanowires consist of alternating layers of magnetic (e.g., Co) and sacrificial materials (e.g., Cu) inside the nanometer-sized pores of an anodized aluminum oxide (AAO) template. The diameter of each layer is determined by pore size, while the thickness is controlled by electrodeposition time. The selective wet etching step removes sacrificial layers, leaving the magnetic nanodiscs. Through this process, the magnetic nanodiscs are fabricated with aspect ratios ranging from 0.25 to 2.0. PMID:25942895

  8. Characterization of multilayers for extended ultraviolet optics

    International Nuclear Information System (INIS)

    We describe an extensive characterization procedure developed to study multilayers for extended ultraviolet (XUV, 1 Aapprox. <λapprox. <1000 A) optics. We present results of this procedure applied to sputtered Si/W multilayers designed as normal-incidence XUV reflectors for --200 A. Techniques used were low-angle x-ray diffraction, Bragg--Brentano and Seemann--Bohlin diffraction, wide-film Debye--Scherrer (Read) camera, Rutherford backscattering spectroscopy, and transmission electron microscopy. Reflectances at several incidence angles were measured with synchrotron radiation and found to agree very well with reflectance curves calculated without adjustable parameters. The information obtained from the different techniques forms a coherent picture of the structure of these materials

  9. Characterization of multilayers for extended ultraviolet optics

    Science.gov (United States)

    Fernández, Félix E.; Falco, Charles M.; Dhez, P.; Khandar-Shahabad, A.; Névot, L.; Pardo, B.; Corno, J.; Vidal, B.

    1987-09-01

    We describe an extensive characterization procedure developed to study multilayers for extended ultraviolet (XUV, 1 Å≲λ≲1000 Å) optics. We present results of this procedure applied to sputtered Si/W multilayers designed as normal-incidence XUV reflectors for ˜200 Å. Techniques used were low-angle x-ray diffraction, Bragg-Brentano and Seemann-Bohlin diffraction, wide-film Debye-Scherrer (Read) camera, Rutherford backscattering spectroscopy, and transmission electron microscopy. Reflectances at several incidence angles were measured with synchrotron radiation and found to agree very well with reflectance curves calculated without adjustable parameters. The information obtained from the different techniques forms a coherent picture of the structure of these materials.

  10. The structure and dynamics of multilayer networks

    Science.gov (United States)

    Boccaletti, S.; Bianconi, G.; Criado, R.; del Genio, C. I.; Gmez-Gardees, J.; Romance, M.; Sendia-Nadal, I.; Wang, Z.; Zanin, M.

    2014-11-01

    In the past years, network theory has successfully characterized the interaction among the constituents of a variety of complex systems, ranging from biological to technological, and social systems. However, up until recently, attention was almost exclusively given to networks in which all components were treated on equivalent footing, while neglecting all the extra information about the temporal- or context-related properties of the interactions under study. Only in the last years, taking advantage of the enhanced resolution in real data sets, network scientists have directed their interest to the multiplex character of real-world systems, and explicitly considered the time-varying and multilayer nature of networks. We offer here a comprehensive review on both structural and dynamical organization of graphs made of diverse relationships (layers) between its constituents, and cover several relevant issues, from a full redefinition of the basic structural measures, to understanding how the multilayer nature of the network affects processes and dynamics.

  11. The structure and dynamics of multilayer networks

    CERN Document Server

    Boccaletti, S; Criado, R; del Genio, C I; Gmez-Gardees, J; Romance, M; Sendia-Nadal, I; Wang, Z; Zanin, M

    2014-01-01

    In the past years, network theory has successfully characterized the interaction among the constituents of a variety of complex systems, ranging from biological to technological, and social systems. However, up until recently, attention was almost exclusively given to networks in which all components were treated on equivalent footing, while neglecting all the extra information about the temporal- or context-related properties of the interactions under study. Only in the last years, taking advantage of the enhanced resolution in real data sets, network scientists have directed their interest to the multiplex character of real-world systems, and explicitly considered the time-varying and multilayer nature of networks. We offer here a comprehensive review on both structural and dynamical organization of graphs made of diverse relationships (layers) between its constituents, and cover several relevant issues, from a full redefinition of the basic structural measures, to understanding how the multilayer nature of...

  12. Solar absorption in thick and multilayered glazings

    Energy Technology Data Exchange (ETDEWEB)

    Powles, Rebecca; Curcija, Dragan; Kohler, Christian

    2002-02-01

    Thick and multilayered glazings generally have a nonuniform distribution of absorbed solar radiation which is not taken into account by current methods for calculating the center of glass solar gain and thermal performance of glazing systems. This paper presents a more accurate method for calculating the distribution of absorbed solar radiation inside thick and multilayered glazings and demonstrates that this can result in a small but significant difference in steady-state temperature profile and Solar Heat Gain Coefficient for some types of glazing systems when compared to the results of current methods. This indicates that a more detailed approach to calculating the distribution of absorbed solar radiation inside glazings and resulting thermal performance may be justified for certain applications.

  13. Perpendicular anisotropy in Fe/Ag multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Fetzer, C.; Szucs, I.S.; Dezsi, I. [KFKI Research Institute for Particle and Nuclear Physics, Budapest (Hungary); Kaptas, D.; Kiss, L.F.; Vincze, I. [Research Institute for Solid State Physics and Optics, Budapest (Hungary); Balogh, J.

    2008-08-15

    The direction of the spontaneous magnetization changes from out of plane to in plane at around x=0.6 in[Ag(2.6 nm)/Fe(x nm)]{sub 10} multilayers (0.2{<=}x{<=}1) prepared on Si(111) substrate by vacuum evaporation. Transmission Moessbauer spectroscopy measurements of removed samples with a thick capping layer are compared to conversion electron Moessbauer spectroscopy measurements of samples on the Si substrate with a thin capping layer. The stress arising because of the application of a thick capping layer and the removal of the samples from the substrate is shown to have negligible effect on the spontaneous magnetization. The results support that the appearance of the perpendicular anisotropy below x=0.6 is an intrinsic property of Fe/Ag multilayers. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Polyelectrolyte Multilayer Capsules for Medical Applications

    OpenAIRE

    Nazarenus, Moritz

    2015-01-01

    This thesis deals with the application of polymer capsules for diagnostic and therapeutic purposes in mammalian cells. The capsules comprise a multilayer shell of oppositely charged polyelectrolytes surrounding a cavity and have a size of two to five microns. Concerning diagnostics, capsules were produced to monitor the dynamics of the lysosomal pH in cancer cells. The cavities of the capsules were filled with a fluoresce...

  15. A Multilayer Model of Computer Networks

    OpenAIRE

    Andrey A. Shchurov

    2015-01-01

    The fundamental concept of applying the system methodology to network analysis declares that network architecture should take into account services and applications which this network provides and supports. This work introduces a formal model of computer networks on the basis of the hierarchical multilayer networks. In turn, individual layers are represented as multiplex networks. The concept of layered networks provides conditions of top-down consistency of the model. Next, we determined the...

  16. Thermal Conduction in Graphene and Graphene Multilayers

    OpenAIRE

    Ghosh, Suchismita

    2009-01-01

    There has been increasing interest in thermal conductivity of materials motivated by the heat removal issues in electronics and by the need of fundamental science to understand heat conduction at nanoscale. This dissertation reports the results of the experimental investigation of heat conduction in graphene and graphene multilayers. Graphene is a planar single sheet of sp2–bonded carbon atoms arranged in honeycomb lattice. It reveals many unique properties, including the extraordinaril...

  17. Multilayer nanofilms as substrates for hepatocellular applications.

    Science.gov (United States)

    Wittmer, Corinne R; Phelps, Jennifer A; Lepus, Christin M; Saltzman, William M; Harding, Martha J; Van Tassel, Paul R

    2008-10-01

    Multilayer nanofilms, formed by the layer-by-layer (LbL) adsorption of positively and negatively charged polyelectrolytes, are promising substrates for tissue engineering. We investigate here the attachment and function of hepatic cells on multilayer films in terms of film composition, terminal layer, rigidity, charge, and presence of biofunctional species. Human hepatocellular carcinoma (HepG2) cells, adult rat hepatocytes (ARH), and human fetal hepatoblasts (HFHb) are studied on films composed of the polysaccharides chitosan (CHI) and alginate (ALG), the polypeptides poly(l-lysine) (PLL) and poly(l-glutamic acid) (PGA), and the synthetic polymers poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS). The influence of chemical cross-linking following LbL assembly is also investigated. We find HepG2 to reach confluence after 7 days of culture on only 2 of 18 candidate multilayer systems: (PAH-PSS)(n) (i.e. nPAH-PSS bilayers) and cross-linked (PLL-ALG)(n)-PLL. Cross-linked PLL-ALG and PLL-PGA films support attachment and function of ARH, independently of the terminal layer, provided collagen is adsorbed to the top of the film. (PAH-PSS)(n), cross-linked (PLL-ALG)(n), and cross-linked (PLL-PGA)(n)-PLL films all support attachment, layer confluence, and function of HFHb, with the latter film promoting the greatest level of function at 8 days. Overall, film composition, terminal layer, and rigidity are key variables in promoting attachment and function of hepatic cells, while film charge and biofunctionality are somewhat less important. These studies reveal optimal candidate multilayer biomaterials for human liver tissue engineering applications. PMID:18653230

  18. Principles of Bragg-Fresnel multilayer optics

    OpenAIRE

    Aristov, V. V.; Erko, A.I.; Martynov, V.V.

    1988-01-01

    The paper describes the principles and theoretical models of new X-ray optical elements based on the behaviour of Bragg-Fresnel diffraction. The use of volume diffraction permits one to achieve better spatial resolution compared with conventional plane optics and bending mirrors. The construction of Bragg-Fresnel elements combines the advantages of high-resolution Fresnel optics with stability of multilayer mirrors.

  19. Fracture mechanics parameters of multilayer pipes

    OpenAIRE

    Šestáková L.; Náhlík L.; Hutař P.; Knésl Z.

    2007-01-01

    Multilayer pipes consisting of different materials are frequently used in praxis because of partial improvement of the properties of pipe systems. To estimate lifetime of these pipes the basic fracture parameters have to be determined. In this work finite element calculations are applied in order to estimate the stress intensity factor K and T-stress values for a new type of non-homogenous C-shape specimen. The application of calculated K and T values to laboratory estimation of fracture toug...

  20. Wetpaint: Scraping Through Multi-Layered Images

    OpenAIRE

    Bonanni, Leonardo Amerigo; XIAO Xiao; Hockenberry, Matthew; Subramani, Praveen; ISHII, HIROSHI; Seracini, Maurizio; Schulze, Jurgen

    2009-01-01

    We introduce a technique for exploring multi-layered images by scraping arbitrary areas to determine meaningful relationships. Our system, called Wetpaint, uses perceptual depth cues to help users intuitively navigate between corresponding layers of an image, allowing a rapid assessment of changes and relationships between different views of the same area. Inspired by art diagnostic techniques, this tactile method could have distinct advantages in the general domain as shown by our user study...

  1. Polyelectrolyte multilayers for plasmonics and picosecond ultrasonics

    OpenAIRE

    Mitzscherling, Steffen

    2015-01-01

    This thesis investigates the application of polyelectrolyte multilayers in plasmonics and picosecond acoustics. The observed samples were fabricated by the spin-assisted layer-by-layer deposition technique that allowed a precise tuning of layer thickness in the range of few nanometers. The first field of interest deals with the interaction of light-induced localized surface plasmons (LSP) of rod-shaped gold nanoparticles with the particles' environment. The environment consists of an air...

  2. Optical absorption spectrum in disordered semiconductor multilayers

    OpenAIRE

    Saffarzadeh, Alireza; Gharaee, Leili

    2010-01-01

    The effects of chemical disorder on the electronic and optical properties of semiconductor alloy multilayers are studied based on the tight-binding theory and single-site coherent potential approximation. Due to the quantum confinement of the system, the electronic spectrum breaks into a set of subbands and the electronic density of states and hence the optical absorption spectrum become layer-dependent. We find that, the values of absorption depend on the alloy concentration, the strength of...

  3. Magneto-optical properties of multilayer graphenes

    OpenAIRE

    Koshino, Mikito; Ando, Tsuneya

    2008-01-01

    The magneto-optical absorption properties of graphene multilayers are theoretically studied. It is shown that the spectrum can be decomposed into sub-components effectively identical to the monolayer or bilayer graphene, allowing us to understand the spectrum systematically as a function of the layer number. Odd-layered graphenes always exhibit absorption peaks which shifts in proportion to sqrt(B), with B being the magnetic field, due to the existence of an effective monolayer-like subband. ...

  4. Development of multilayered chitosan-based nanofibers

    OpenAIRE

    Croisier, Florence; Aqil, Abdelhafid; Detrembleur, Christophe; Jérôme, Christine

    2009-01-01

    By combining electrospinning and layer-by-layer deposition techniques, new porous material scaffolds of multilayered, chitosan-based nanofibers were produced. Layer-by-layer (LBL) is a well-known method for surface coating, based on electrostatic interactions. It enables the controllable deposition of a variety of polyelectrolytes including synthetic and natural materials, with designable layer structure, defined layer thickness and size. Electrospinning (ESP) allows the fabrication of po...

  5. Spin transport in molybdenum disulfide multilayer channel

    OpenAIRE

    Liang, S. H.; Lu, Y.; Tao, B. S.; Mc-Murtry, S.; G. Wang; Marie, X.; Renucci, P.; Jaffrs, H.; Montaigne, F.; Lacour, D.; George, J.-M.; Petit-Watelot, S.; Hehn, M.; Djeffal, A.; Mangin, S.

    2015-01-01

    Molybdenum disulfide has recently emerged as a promising two-dimensional semiconducting material for nano-electronic, opto-electronic and spintronic applications. However, demonstrating spin-transport through a semiconducting MoS2 channel is challenging. Here we demonstrate the electrical spin injection and detection in a multilayer MoS2 semiconducting channel. A magnetoresistance (MR) around 1% has been observed at low temperature through a 450nm long, 6 monolayer thick channel with a Co/MgO...

  6. Analysis of Fracture Behaviour of Multilayer Pipes

    Czech Academy of Sciences Publication Activity Database

    Nezbedová, E.; Knésl, Zdeněk; Vlach, B.

    2007-01-01

    Roč. 36, č. 5 (2007), s. 207-212. ISSN 1465-8011. [Plastic Pipes /13./. Washington, D. C., 02.10.2006-05.10.2006] R&D Projects: GA ČR GA106/07/1284 Institutional research plan: CEZ:AV0Z20410507 Keywords : multi-layer pipes Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.431, year: 2007

  7. Surface immobilized protein multilayers for cell seeding

    Czech Academy of Sciences Publication Activity Database

    Brynda, Eduard; Pacherník, J.; Houska, Milan; Pientka, Zbyněk; Dvořák, P.

    2005-01-01

    Roč. 21, č. 17 (2005), s. 7877. ISSN 0743-7463 R&D Projects: GA ČR(CZ) GA203/02/1326; GA ČR GA102/03/0633; GA MŠk(CZ) LN00A065 Keywords : surface modification * layer-by-layer deposition * protein multilayers Subject RIV: CE - Biochemistry Impact factor: 3.705, year: 2005

  8. Superabsorption of light by multilayer nanowires.

    Science.gov (United States)

    Mirzaei, Ali; Shadrivov, Ilya V; Miroshnichenko, Andrey E; Kivshar, Yuri S

    2015-11-14

    We suggest a new strategy for tailoring and enhancing the absorption of light by multilayered nanowires. We use the multipole expansion method and experimental data for dielectric and plasmonic materials and demonstrate that the absorption for one of the polarizations can be substantially enhanced due to an overlap of different resonant modes in nanowires. We show that our approach can be employed for a design of multiband tunable optical absorption across a wide spectral range for both TE and TM polarizations. PMID:26462974

  9. Suppression of Brazier Effect in Multilayered Cylinders

    OpenAIRE

    Hiroyuki Shima; Motohiro Sato; Sung-Jin Park

    2014-01-01

    When a straight hollow tube having circular cross-section is bent uniformly into an arc, the cross-section tends to ovalize or flatten due to the in-plane stresses induced by bending; this ovalization phenomenon is called the Brazier effect. The present paper is aimed at theoretical formulation of the Brazier effect observed in multilayered cylinders, in which a set of thin hollow cylinders are stacked concentrically about the common axis. The results indicate that mechanical couplings betwee...

  10. Magnetic properties of Tm-Zr multilayers

    International Nuclear Information System (INIS)

    A 600 A film of thulium and Tm-Zr multilayers in which the Tm layers are separated by 30 A non-magnetic Zr layers were evaporated on superficially oxidized silicon substrates under ultra-vacuum conditions. The thickness of the Tm layers was varied between 8 and 30 A. X-ray diffraction gives evidence for a columnar growth along the c axis of the HCP structure, with in-plane compression of Tm layers thinner than 20 A. The magnetic structure of the film is quite similar to that of bulk Tm. On the contrary, the c-axis modulated antiferromagnetic phase which takes place in the film at TN∼54 K is not observed in the multilayers. This phenomenon is preferentially attributed to an enhancement of the ferromagnetic coupling at the edges of the thulium layers, which favours a structure close to the squared 3-4 antiphase ferromagnetic arrangement of the magnetic moments displayed by the bulk below 30 K. A marked trend to ferromagnetism is observed as the Tm layers become thinner. Contrary to that observed in Dy-Zr and Ho-Zr multilayers, the interface and volume anisotropies do not compensate each other for 8 A Tm layers. The c-axis magnetic anisotropy of Tm is preserved whatever the thickness of the Tm layers. The estimated anisotropies are compared with the results of point-charge crystal-field calculations. (orig.)

  11. Quantum Spin Hall phase in multilayer graphene

    Science.gov (United States)

    Garcia, Noel; Lado, Jose Luis; Fernandez-Rossier, Joaquin; Theory of Nanostructures Team

    2015-03-01

    We address the question of whether multilayer graphene systems are Quantum Spin Hall (QSH) insulators. Since interlayer coupling coples pz orbitals to s orbitals of different layers and Spin-Orbit (SO) couples pz orbitals with px and py of opposite spins, new spins mixing channels appear in the multilayer scenario that were not present in the monolayer. These new spin-mixing channels cast a doubt on the validity of the spin-conserving Kane-Mele model for multilayers and motivates our choice of a four orbital tight-binding model in the Slater-Koster approximation with intrinsic Spin-Orbit interaction. To completely determine if the QSH phase is present we calculate for different number of layers both the Z2 invariant for different stackings (only for inversion symmetric systems), and the density of states at the edge of semi-infinite graphene ribbon with armchair termination. We find that systems with even number of layers are normal insulators while systems with odd number of layers are QSH insulators, regardless of the stacking. We acknowledge financial support by Marie-Curie-ITN 607904-SPINOGRAPH.

  12. Automation Enhancement of Multilayer Laue Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Lauer K. R.; Conley R.

    2010-12-01

    X-ray optics fabrication at Brookhaven National Laboratory has been facilitated by a new, state of the art magnetron sputtering physical deposition system. With its nine magnetron sputtering cathodes and substrate carrier that moves on a linear rail via a UHV brushless linear servo motor, the system is capable of accurately depositing the many thousands of layers necessary for multilayer Laue lenses. I have engineered a versatile and automated control program from scratch for the base system and many subsystems. Its main features include a custom scripting language, a fully customizable graphical user interface, wireless and remote control, and a terminal-based interface. This control system has already been successfully used in the creation of many types of x-ray optics, including several thousand layer multilayer Laue lenses.Before reaching the point at which a deposition can be run, stencil-like masks for the sputtering cathodes must be created to ensure the proper distribution of sputtered atoms. Quality of multilayer Laue lenses can also be difficult to measure, given the size of the thin film layers. I employ my knowledge of software and algorithms to further ease these previously painstaking processes with custom programs. Additionally, I will give an overview of an x-ray optic simulator package I helped develop during the summer of 2010. In the interest of keeping my software free and open, I have worked mostly with the multiplatform Python and the PyQt application framework, utilizing C and C++ where necessary.

  13. Evolutionary games on multilayer networks: a colloquium

    Science.gov (United States)

    Wang, Zhen; Wang, Lin; Szolnoki, Attila; Perc, Matjaž

    2015-05-01

    Networks form the backbone of many complex systems, ranging from the Internet to human societies. Accordingly, not only is the range of our interactions limited and thus best described and modeled by networks, it is also a fact that the networks that are an integral part of such models are often interdependent or even interconnected. Networks of networks or multilayer networks are therefore a more apt description of social systems. This colloquium is devoted to evolutionary games on multilayer networks, and in particular to the evolution of cooperation as one of the main pillars of modern human societies. We first give an overview of the most significant conceptual differences between single-layer and multilayer networks, and we provide basic definitions and a classification of the most commonly used terms. Subsequently, we review fascinating and counterintuitive evolutionary outcomes that emerge due to different types of interdependencies between otherwise independent populations. The focus is on coupling through the utilities of players, through the flow of information, as well as through the popularity of different strategies on different network layers. The colloquium highlights the importance of pattern formation and collective behavior for the promotion of cooperation under adverse conditions, as well as the synergies between network science and evolutionary game theory.

  14. Heat Transfer in High Temperature Multilayer Insulation

    Science.gov (United States)

    Daryabeigi, Kamran; Miller, Steve D.; Cunnington, George R.

    2007-01-01

    High temperature multilayer insulations have been investigated as an effective component of thermal-protection systems for atmospheric re-entry of reusable launch vehicles. Heat transfer in multilayer insulations consisting of thin, gold-coated, ceramic reflective foils and Saffil(TradeMark) fibrous insulation spacers was studied both numerically and experimentally. A finite volume numerical thermal model using combined conduction (gaseous and solid) and radiation in porous media was developed. A two-flux model with anisotropic scattering was used for radiation heat transfer in the fibrous insulation spacers between the reflective foils. The thermal model was validated by comparison with effective thermal conductivity measurements in an apparatus based on ASTM standard C201. Measurements were performed at environmental pressures in the range from 1x10(exp -4) to 760 torr over the temperature range from 300 to 1300 K. Four multilayer samples with nominal densities of 48 kg/cu m were tested. The first sample was 13.3 mm thick and had four evenly spaced reflective foils. The other three samples were 26.6 mm thick and utilized either one, two, or four reflective foils, located near the hot boundary with nominal foil spacing of 1.7 mm. The validated thermal model was then used to study relevant design parameters, such as reflective foil spacing and location in the stack-up and coating of one or both sides of foils.

  15. Technique for etching monolayer and multilayer materials

    Energy Technology Data Exchange (ETDEWEB)

    Bouet, Nathalie C. D.; Conley, Raymond P.; Divan, Ralu; Macrander, Albert

    2015-10-06

    A process is disclosed for sectioning by etching of monolayers and multilayers using an RIE technique with fluorine-based chemistry. In one embodiment, the process uses Reactive Ion Etching (RIE) alone or in combination with Inductively Coupled Plasma (ICP) using fluorine-based chemistry alone and using sufficient power to provide high ion energy to increase the etching rate and to obtain deeper anisotropic etching. In a second embodiment, a process is provided for sectioning of WSi.sub.2/Si multilayers using RIE in combination with ICP using a combination of fluorine-based and chlorine-based chemistries and using RF power and ICP power. According to the second embodiment, a high level of vertical anisotropy is achieved by a ratio of three gases; namely, CHF.sub.3, Cl.sub.2, and O.sub.2 with RF and ICP. Additionally, in conjunction with the second embodiment, a passivation layer can be formed on the surface of the multilayer which aids in anisotropic profile generation.

  16. Multilayer modal actuator-based piezoelectric transformers.

    Science.gov (United States)

    Huang, Yao-Tien; Wu, Wen-Jong; Wang, Yen-Chieh; Lee, Chih-Kung

    2007-02-01

    An innovative, multilayer piezoelectric transformer equipped with a full modal filtering input electrode is reported herein. This modal-shaped electrode, based on the orthogonal property of structural vibration modes, is characterized by full modal filtering to ensure that only the desired vibration mode is excited during operation. The newly developed piezoelectric transformer is comprised of three layers: a multilayered input layer, an insulation layer, and a single output layer. The electrode shape of the input layer is derived from its structural vibration modal shape, which takes advantage of the orthogonal property of the vibration modes to achieve a full modal filtering effect. The insulation layer possesses two functions: first, to couple the mechanical vibration energy between the input and output, and second, to provide electrical insulation between the two layers. To meet the two functions, a low temperature, co-fired ceramic (LTCC) was used to provide the high mechanical rigidity and high electrical insulation. It can be shown that this newly developed piezoelectric transformer has the advantage of possessing a more efficient energy transfer and a wider optimal working frequency range when compared to traditional piezoelectric transformers. A multilayer piezoelectric, transformer-based inverter applicable for use in LCD monitors or portable displays is presented as well. PMID:17328332

  17. Multilayer network decoding versatility and trust

    Science.gov (United States)

    Sarkar, Camellia; Yadav, Alok; Jalan, Sarika

    2016-01-01

    In the recent years, the multilayer networks have increasingly been realized as a more realistic framework to understand emergent physical phenomena in complex real-world systems. We analyze massive time-varying social data drawn from the largest film industry of the world under a multilayer network framework. The framework enables us to evaluate the versatility of actors, which turns out to be an intrinsic property of lead actors. Versatility in dimers suggests that working with different types of nodes are more beneficial than with similar ones. However, the triangles yield a different relation between type of co-actor and the success of lead nodes indicating the importance of higher-order motifs in understanding the properties of the underlying system. Furthermore, despite the degree-degree correlations of entire networks being neutral, multilayering picks up different values of correlation indicating positive connotations like trust, in the recent years. The analysis of weak ties of the industry uncovers nodes from a lower-degree regime being important in linking Bollywood clusters. The framework and the tools used herein may be used for unraveling the complexity of other real-world systems.

  18. Interline power flow controller (IPFC) based damping recurrent neural network controllers for enhancing stability

    International Nuclear Information System (INIS)

    Highlights: → A method is presented to improve power system stability using IPFC. → Recurrent neural network controllers damp oscillations in a power system. → Training is based on back propagation with adaptive training parameters. → Selection of effectiveness damping control signal carried out using SVD method. -- Abstract: This paper presents a method to improve power system stability using IPFC based damping online learning recurrent neural network controllers for damping oscillations in a power system. Parameters of equipped controllers for enhancing dynamical stability at the IPFC are tuned using mathematical methods. Therefore these control parameters are often fixed and are set for particular system configurations or operating points. Multilayer recurrent neural network, which can be tuned for changing system conditions, is used in this paper for effectively damp the oscillations. Training is based on back propagation with adaptive training parameters. This controller is tested to variations in system loading and fault in the power system and its performance is compared with performance of a controller that the phase compensation method is used to set its parameters. Selection of effectiveness damping control signal for the design of robust IPFC damping controller carried out through singular value decomposition (SVD) method. Simulation studies show the superior robustness and stabilizing effect of the proposed controller in comparison with phase compensation method.

  19. An ensemble perspective on multi-layer networks

    CERN Document Server

    Wider, Nicolas; Scholtes, Ingo; Schweitzer, Frank

    2015-01-01

    We study properties of multi-layered, interconnected networks from an ensemble perspective, i.e. we analyze ensembles of multi-layer networks that share similar aggregate characteristics. Using a diffusive process that evolves on a multi-layer network, we analyze how the speed of diffusion depends on the aggregate characteristics of both intra- and inter-layer connectivity. Through a block-matrix model representing the distinct layers, we construct transition matrices of random walkers on multi-layer networks, and estimate expected properties of multi-layer networks using a mean-field approach. In addition, we quantify and explore conditions on the link topology that allow to estimate the ensemble average by only considering aggregate statistics of the layers. Our approach can be used when only partial information is available, like it is usually the case for real-world multi-layer complex systems.

  20. Conjunctival Autograft in Primary and Recurrent Pterygium: A Study

    OpenAIRE

    Salagar, Kavita Mallikarjun; Biradar, Kalyanappa Gurlingappa

    2013-01-01

    Aim: Investigate the efficiency of limbal conjunctival autograft in primary and recurrent pterygium. (2) To report the incidence of recurrence after primary and recurrent pterygium surgery using limbal conjunctival autograft.

  1. Immunopathogenesis of recurrent vulvovaginal candidiasis.

    Science.gov (United States)

    Fidel, P L; Sobel, J D

    1996-07-01

    Recurrent vulvovaginal candidiasis (RVVC) is a prevalent opportunistic mucosal infection, caused predominantly by Candida albicans, which affects a significant number of otherwise healthy women of childbearing age. Since there are no known exogenous predisposing factors to explain the incidence of symptomatic vaginitis in most women with idiopathic RVVC, it has been postulated that these particular women suffer from an immunological abnormality that prediposes them to RVVC. Because of the increased incidence of mucosal candidiasis in individuals with depressed cell-mediated immunity (CMI), defects in CMI are viewed as a possible explanation for RVVC. In this review, we attempt to place into perspective the accumulated information regarding the immunopathogenesis of RVVC, as well as to provide new immunological perspectives and hypotheses regarding potential immunological deficiencies that may predispose to RVVC and potentially other mucosal infections by the same organism. The results of both clinical studies and studies in an animal model of experimental vaginitis suggest that systemic CMI may not be the predominant host defense mechanism against C. albicans vaginal infections. Rather, locally acquired mucosal immunity, distinct from that in the peripheral circulation, is now under consideration as an important host defense at the vaginal mucosa, as well as the notion that changes in local CMI mechanism(s) may predispose to RVVC. PMID:8809464

  2. Treatment of Recurrent Ovarian Cancer.

    Directory of Open Access Journals (Sweden)

    Neville F. Hacker

    2004-08-01

    Full Text Available Recurrent ovarian cancer is a common clinical problem and the management of eachpatient must be individualized. Diagnosis is usually based on a progressively rising CA-125titre, and a CT scan of the pelvis and abdomen, together with a chest X-ray should be performed.Although there is no study to support immediate treatment in the asymptomaticpatient, our approach is to commence such patients on Tamoxifen. Chemotherapy isreserved for asymptomatic patients or those who progress on Tamoxifen. The longer thetreatment-free interval of 18-24 months. The choice of non-platinum second or subsequentline chemotherapy is based on many factors including likelihood of benefit, potential toxicity,schedule and convenience to the patient, as well as organ function and residual toxicityfrom prior treatment. Aggressive secondary cytoreductive surgery can significantly prolongsurvival in those with a disease-free interval of 24 months or more and in those in whom allmacroscopic disease can be removed. Radiation therapy to the tumour bed following resectionof localized disease may be beneficial in selected patients. Quality of life issues are particularlyimportant for this group of patients and have not been adequately studies.Communication regarding the objectives of therapy is important, and the multidisciplinaryapproach should include palliative care and psycho-social support, in addition to the moretraditional medical options.

  3. Forecasting US unemployment with radial basis neural networks, kalman filters and support vector regressions

    OpenAIRE

    Stasinakis, Charalampos; Sermpinis, Georgios; Theofilatos, Konstantinos; Karathanasopoulos, Andreas

    2015-01-01

    This study investigates the efficiency of the radial basis function neural networks in forecasting the US unemployment and explores the utility of Kalman filter and support vector regression as forecast combination techniques. On one hand, an autoregressive moving average model, a smooth transition autoregressive model and three different neural networks architectures, namely a multi-layer perceptron, recurrent neural network and a psi sigma network are used as benchmarks for our radial basis...

  4. Artificial neural networks applied to forecasting time series

    OpenAIRE

    Montaño Moreno, Juan José; Palmer Pol, Alfonso; Muñoz Gracia, María del Pilar

    2011-01-01

    This study offers a description and comparison of the main models of Artificial Neural Networks (ANN) which have proved to be useful in time series forecasting, and also a standard procedure for the practical application of ANN in this type of task. The Multilayer Perceptron (MLP), Radial Base Function (RBF), Generalized Regression Neural Network (GRNN), and Recurrent Neural Network (RNN) models are analyzed. With this aim in mind, we use a time series made up of 244 time points. A comparativ...

  5. Multilayered Polymer Coated Carbon Nanotubes to Deliver Dasatinib

    OpenAIRE

    Moore, Thomas L.; Grimes, Stuart W.; Lewis, Robert L.; Alexis, Frank

    2013-01-01

    Multilayered, multifunctional polymer coatings were grafted onto carbon nanotubes (CNT) using a one-pot, ring-opening polymerization in order to control the release kinetic and therapeutic efficacy of dasatinib. Biocompatible, biodegradable multilayered coatings composed of poly(glycolide) (PGA), and poly(lactide) (PLA) were polymerized directly onto hydroxyl-functionalized CNT surfaces. Sequential addition of monomers into the reaction vessel enabled multilayered coatings of PLA-PGA, or PGA-...

  6. Reactive multilayers fabricated by vapor deposition: A critical review

    International Nuclear Information System (INIS)

    Reactive multilayer thin films are a class of energetic materials that continue to attract attention for use in joining applications and as igniters. Generally composed of two reactants, these heterogeneous solids can be stimulated by an external source to promptly release stored chemical energy in a sudden emission of light and heat. In this critical review article, results from recent investigations of these materials are discussed. Discussion begins with a brief description of the vapor deposition techniques that provide accurate control of layer thickness and film composition. More than 50 reactive film compositions have been reported to date, with most multilayers fabricated by magnetron sputter deposition or electron-beam evaporation. In subsequent sections, we review how multilayer ignition threshold, reaction rate, and total heat are tailored via thin film design. For example, planar multilayers with nanometer-scale periodicity exhibit rapid, self-sustained reactions with wavefront velocities up to 100 m/s. Numeric and analytical models have elucidated many of the fundamental processes that underlie propagating exothermic reactions while demonstrating how reaction rates vary with multilayer design. Recent, time-resolved diffraction and imaging studies have further revealed the phase transformations and the wavefront dynamics associated with propagating chemical reactions. Many reactive multilayers (e.g., Co/Al) form product phases that are consistent with published equilibrium phase diagrams, yet a few systems, such as Pt/Al, develop metastable products. The final section highlights current and emerging applications of reactive multilayers. Examples include reactive Ni(V)/Al and Pd/Al multilayers which have been developed for localized soldering of heat-sensitive components. - Highlights: • Vapor-deposited, reactive multilayers and their properties are reviewed. • This article includes discussion of various structure-property relationships. • Multilayers can be ignited at a point or by uniform heating. • Reactive multilayers can exhibit self-sustained, rapid deflagration reactions • This review summarizes current and emerging applications of reactive multilayers

  7. Multilayer microwave structures using thick-film technology.

    OpenAIRE

    Tian, Zhengrong

    2002-01-01

    Multilayer techniques, in conjunction with thick-film technology have been applied to the design and fabrication of several multilayer microwave structures to achieve the low cost and high performance goals set by modern microwave circuits and systems. To provide accurate material parameters for the design of multilayer thick-film components, a novel slit cavity resonator method has been developed that enables the relative permittivity and loss tangent of dielectric samples to be measured ...

  8. Neutron diffraction studies of thin film multilayer structures

    International Nuclear Information System (INIS)

    The application of neutron diffraction methods to the study of the microscopic chemical and magnetic structures of thin film multilayers is reviewed. Multilayer diffraction phenomena are described in general and in particular for the case in which one of the materials of a bilayer is ferromagnetic and the neutron beam polarized. Recent neutron diffraction measurements performed on some interesting multilayer systems are discussed. 70 refs., 5 figs

  9. Etched-multilayer phase shifting masks for EUV lithography

    Science.gov (United States)

    Chapman, Henry N.; Taylor, John S.

    2005-04-05

    A method is disclosed for the implementation of phase shifting masks for EUV lithography. The method involves directly etching material away from the multilayer coating of the mask, to cause a refractive phase shift in the mask. By etching into the multilayer (for example, by reactive ion etching), rather than depositing extra material on the top of the multilayer, there will be minimal absorption loss associated with the phase shift.

  10. Stress in tungsten carbide-diamond like carbon multilayer coatings

    OpenAIRE

    Pujada, B.R.; Tichelaar, F. D.; Janssen, G.C.A.M.

    2007-01-01

    Tungsten carbide-diamond like carbon (WC-DLC) multilayer coatings have been prepared by sputter deposition from a tungsten-carbide target and periodic switching on and off of the reactive acetylene gas flow. The stress in the resulting WC-DLC multilayers has been studied by substrate curvature. Periodicity and microstructure have been studied by transmission electron microscopy. It has been observed that compressive stress in the multilayers decreases when the bilayer thickness is reduced. Re...

  11. Stress in tungsten carbide-diamond like carbon multilayer coatings:

    OpenAIRE

    Pujada, B.R.; Tichelaar, F. D.; Janssen, G. C. A. M.

    2007-01-01

    Tungsten carbide-diamond like carbon (WC-DLC) multilayer coatings have been prepared by sputter deposition from a tungsten-carbide target and periodic switching on and off of the reactive acetylene gas flow. The stress in the resulting WC-DLC multilayers has been studied by substrate curvature. Periodicity and microstructure have been studied by transmission electron microscopy. It has been observed that compressive stress in the multilayers decreases when the bilayer thickness is reduced. Re...

  12. Eigenfunctional representation of dyadic Green's functions in multilayered gyrotropic chiral media

    International Nuclear Information System (INIS)

    Studying electromagnetic waves in complex media has been an important research topic due to its useful applications and scientific significance of its physical performance. Dyadic Green's functions (DGFs), as a mathematical kernel or a dielectric medium response, have long been a valuable tool in solving both source-free and source-incorporated electromagnetic boundary value problems for electromagnetic scattering, radiation and propagation phenomena. A complete eigenfunctional expansion of the dyadic Green's functions for an unbounded and a planar, arbitrary multilayered gyrotropic chiral media is formulated in terms of the vector wavefunctions. After a general representation of Green's dyadics is obtained, the scattering coefficients of Green's dyadics are determined from the boundary conditions at each interface and are expressed in a greatly compact form of recurrence matrices. In the formulation of Green's dyadics and their scattering coefficients, three cases are considered, i.e. the current source is immersed in (1) the first, (2) the intermediate, and (3) the last regions, respectively. Although the dyadic Green's functions for an unbounded gyroelectric medium has been reported in the literature, we here present not only unbounded but also multilayered DGFs for the gyrotropic chiral media. The explicit representation of the DGFs after reduction to the gyroelectric or isotropic case agrees well with those existing corresponding results

  13. Eigenfunctional representation of dyadic Green's functions in multilayered gyrotropic chiral media

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, C-W [Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore 117576, Singapore (Singapore); Yao, H-Y [Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore 117576, Singapore (Singapore); Li, L-W [Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore 117576, Singapore (Singapore); Zouhdi, Said [Lab de Genie Electrique de Paris, CNRS, Ecole Superieure d' Electricite, Plateau de Moulon 91192, Gif-sur-Yvette Cedex (France); Yeo, T-S [Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore 117576, Singapore (Singapore)

    2007-05-25

    Studying electromagnetic waves in complex media has been an important research topic due to its useful applications and scientific significance of its physical performance. Dyadic Green's functions (DGFs), as a mathematical kernel or a dielectric medium response, have long been a valuable tool in solving both source-free and source-incorporated electromagnetic boundary value problems for electromagnetic scattering, radiation and propagation phenomena. A complete eigenfunctional expansion of the dyadic Green's functions for an unbounded and a planar, arbitrary multilayered gyrotropic chiral media is formulated in terms of the vector wavefunctions. After a general representation of Green's dyadics is obtained, the scattering coefficients of Green's dyadics are determined from the boundary conditions at each interface and are expressed in a greatly compact form of recurrence matrices. In the formulation of Green's dyadics and their scattering coefficients, three cases are considered, i.e. the current source is immersed in (1) the first, (2) the intermediate, and (3) the last regions, respectively. Although the dyadic Green's functions for an unbounded gyroelectric medium has been reported in the literature, we here present not only unbounded but also multilayered DGFs for the gyrotropic chiral media. The explicit representation of the DGFs after reduction to the gyroelectric or isotropic case agrees well with those existing corresponding results.

  14. Inguinal hernia recurrence: Classification and approach

    Directory of Open Access Journals (Sweden)

    Campanelli Giampiero

    2006-01-01

    Full Text Available The authors reviewed the records of 2,468 operations of groin hernia in 2,350 patients, including 277 recurrent hernias updated to January 2005. The data obtained - evaluating technique, results and complications - were used to propose a simple anatomo-clinical classification into three types which could be used to plan the surgical strategy:Type R1: first recurrence ′high,′ oblique external, reducible hernia with small (< 2 cm defect in non-obese patients, after pure tissue or mesh repairType R2: first recurrence ′low,′ direct, reducible hernia with small (< 2 cm defect in non-obese patients, after pure tissue or mesh repairType R3: all the other recurrences - including femoral recurrences; recurrent groin hernia with big defect (inguinal eventration; multirecurrent hernias; nonreducible, linked with a controlateral primitive or recurrent hernia; and situations compromised from aggravating factors (for example obesity or anyway not easily included in R1 or R2, after pure tissue or mesh repair.

  15. Empirical Evaluation of Gated Recurrent Neural Networks on Sequence Modeling

    OpenAIRE

    Chung, Junyoung; Gulcehre, Caglar; Cho, Kyunghyun; Bengio, Yoshua

    2014-01-01

    In this paper we compare different types of recurrent units in recurrent neural networks (RNNs). Especially, we focus on more sophisticated units that implement a gating mechanism, such as a long short-term memory (LSTM) unit and a recently proposed gated recurrent unit (GRU). We evaluate these recurrent units on the tasks of polyphonic music modeling and speech signal modeling. Our experiments revealed that these advanced recurrent units are indeed better than more traditional recurrent unit...

  16. The first example of multilayer films with thermochromic properties

    International Nuclear Information System (INIS)

    A novel thermochromic multilayer film containing polyoxometalate cluster K12.5Na1.5[NaP5W30O110] has been fabricated by layer-by-layer self-assembly method. In case of the multilayer film, the color changes gradually from yellowish to blue when it is subjected to temperatures between 120 deg. C and 180 deg. C for a period of time, and the multilayer film could be bleached in air at room temperature to recover its initial state. The novel thermochromic multilayer may be of practical benefit in the development of thermosensors, which would represent promising materials for future applications

  17. The first example of multilayer films with thermochromic properties

    Science.gov (United States)

    Jiang, Min; Wang, Enbo; Xu, Lin; Kang, Zhenhui; Lian, Suoyuan

    2004-04-01

    A novel thermochromic multilayer film containing polyoxometalate cluster K 12.5Na 1.5[NaP 5W 30O 110] has been fabricated by layer-by-layer self-assembly method. In case of the multilayer film, the color changes gradually from yellowish to blue when it is subjected to temperatures between 120°C and 180°C for a period of time, and the multilayer film could be bleached in air at room temperature to recover its initial state. The novel thermochromic multilayer may be of practical benefit in the development of thermosensors, which would represent promising materials for future applications.

  18. Scattering anisotropy and giant magnetoresistance in magnetic multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Binder, J.; Zahn, P.; Mertig, I.

    2001-06-01

    We present full ab initio calculations of giant magnetoresistance (GMR) in Co/Cu (001) multilayers including self-consistent impurity scattering potentials. Starting from density functional theory the electronic structure of the multilayer and the scattering at impurities are described by means of a new Green function method. It will be demonstrated that impurity scattering in magnetic multilayers is strongly anisotropic in comparison to impurity scattering in bulk systems. Concerning transport the anisotropy of scattering leads to a formation of highly conducting channels which give rise to short circuits and cause strong variation of GMR as a function of the impurity position in the multilayer. {copyright} 2001 American Institute of Physics.

  19. Microstructural Characterisation of Giant Magnetoresistive Co/Cu Multilayers

    International Nuclear Information System (INIS)

    Antiferromagnetically-coupled Co/Cu multilayers prepared by magnetron sputtering exhibit pronounced giant magnetoresistance (GMR) effect at room temperature. Using both diffraction and imaging techniques, we studied the in-plane and out-of-plane crystallographic and layering microstructural features of these multilayers. Dominant characteristic features associated with the multilayers, such as lateral and vertical columnar grain orientations as well as layer undulations and regularity, were identified. By deliberately introducing microstructural changes to the materials system using buffer layer and heat treatment, detailed microstructural analysis have provided an insight into the dependence of GMR on microstructures of the multilayers.

  20. Microstructural Characterisation of Giant Magnetoresistive Co/Cu Multilayers

    International Nuclear Information System (INIS)

    Antiferromagnetically-coupled Co/Cu multilayers prepared by magnetron sputtering exhibit pronounced giant magnetoresistance (GMR) effect at room temperature. Using both diffraction and imaging techniques, we studied the in-plane and out-of-plane crystallographic and layering microstructural features of these multilayers. Dominant characteristic features associated with the multilayers, such as the lateral and vertical columnar grain orientations as well as layer undulations and regularity, were identified. By deliberately introducing microstructural changes to the materials system using buffer layer and heat treatment, detailed microstructural analysis had provided an insight into the dependence of GMR on the microstructures of the multilayers.

  1. Generalised Recurrence Plot Analysis for Spatial Data

    CERN Document Server

    Marwan, N; Saparin, P; Marwan, Norbert; Kurths, Juergen; Saparin, Peter

    2006-01-01

    Recurrence plot based methods are highly efficient and widely accepted tools for the investigation of time series or one-dimensional data. We present an extension of the recurrence plots and their quantifications in order to study recurrent structures in higher-dimensional spatial data. The capability of this extension is illustrated on prototypical 2D models. Next, the tested and proved approach is applied to assess the bone structure from CT images of human proximal tibia. We find that the spatial structures in trabecular bone become more self-similar during the bone loss in osteoporosis.

  2. Prevention of Recurrent Staphylococcal Skin Infections.

    Science.gov (United States)

    Creech, C Buddy; Al-Zubeidi, Duha N; Fritz, Stephanie A

    2015-09-01

    Staphylococcus aureus infections pose a significant health burden. The emergence of community-associated methicillin-resistant S aureus has resulted in an epidemic of skin and soft tissue infections (SSTI), and many patients experience recurrent SSTI. As S aureus colonization is associated with subsequent infection, decolonization is recommended for patients with recurrent SSTI or in settings of ongoing transmission. S aureus infections often cluster within households, and asymptomatic carriers serve as reservoirs for transmission; therefore, a household approach to decolonization is more effective than measures performed by individuals alone. Novel strategies for the prevention of recurrent SSTI are needed. PMID:26311356

  3. Recurrence relations for spin foam vertices

    OpenAIRE

    Bonzom, Valentin; Livine, Etera R.; Speziale, Simone

    2010-01-01

    Abstract We study recurrence relations for various Wigner 3nj-symbols and the non-topological 10j-symbol. For the 6j-symbol and the 15j-symbols which correspond to basic amplitudes of 3d and 4d topological spin foam models, recurrence relations are obtained from the invariance under Pachner moves and can be interpreted as quantizations of the constraints of the underlying classical field theories. We also derive recurrences from the action of holonomy operators on spin network functionals,...

  4. Some Recurrence Relations Between Hansen Coefficients

    Science.gov (United States)

    Vakhidov, Akmal A.

    2001-11-01

    A new system of recurrence relations for Hansen coefficients is obtained. This system gives a connection between only those coefficients which are included in the disturbing function of planetary or satellite motion and allows to compute efficiently the Hansen coefficients for perturbations both from internal and external bodies. The recurrence process can be realized both from high to low and from low to high harmonical terms of the disturbing function. The corresponding algorithms of evaluation of Hansen coefficients are presented. The efficiency of the obtained system of recurrence relations is discussed.

  5. Ethanol ablation of predominantly cystic thyroid nodules: Evaluation of recurrence rate and factors related to recurrence

    International Nuclear Information System (INIS)

    Aim: To evaluate recurrence rate and associated risk factors for recurrence after ethanol ablation (EA) in patients with predominantly cystic thyroid nodules. Materials and methods: This observational study was approved by the Ethics Committee of the Institutional Review Board and informed consent for procedures was obtained. From April 2009 to April 2013, 107 consecutive patients with predominantly cystic nodules were treated using EA. Recurrence was defined as nodules showing a residual solid portion with internal vascularity, cosmetic problems remaining, or persistent symptoms, and patients who requested additional therapy to resolve their symptomatic or cosmetic problems. Delayed recurrence was defined as treated nodules that showed no recurrent features at 1 month, but showed newly developed recurrent features during the longer follow-up period. Multivariate analysis was used for variables to demonstrate the independent factors related to volume reduction. Results: One month after EA, 18.7% of patients (20/107) showed recurrence. Among 87 patients with non-recurrence, 24.1% (21/87) showed delayed recurrence. The total recurrence rate was 38.3% (41/107). Patients with recurrence (n = 41) were treated using radiofrequency ablation (n = 28), second EA (n = 4), and refused further treatment (n = 9). These patients responded well to repeat EA and radiofrequency ablation. Multivariate analysis demonstrated that the initial nodule volume (>20 ml; p < 0.036) and vascularity (grade >1; p < 0.049) were independent predictors of volume reduction at last follow-up. Conclusions: The results revealed that although EA seemed to be effective during the initial period, delayed recurrence should be considered during longer-term follow-up. The independent predictors of recurrence were initial volume (>20 ml) and vascularity. - Highlights: • Ethanol ablation showed unsatisfactory results in 18.7% of patient at one month. • Delayed recurrence was observed in 24.1% of patients during the follow-up period. • Total recurrence rate was 38.3% after ethanol ablation. • Our study results revealed that although EA seemed to be effective in the initial period, delayed recurrence should be considered during the longer follow-up period. • The independent predictors of recurrence were initial volume (>20 mL) and vascularity

  6. Recurrence of hypertensive disorders of pregnancy

    DEFF Research Database (Denmark)

    van Oostwaard, Miriam F; Langenveld, Josje; Schuit, Ewoud; Papatsonis, Dimitri N M; Brown, Mark A; Byaruhanga, Romano N; Bhattacharya, Sohinee; Campbell, Doris M; Chappell, Lucy C; Chiaffarino, Francesca; Crippa, Isabella; Facchinetti, Fabio; Ferrazzani, Sergio; Ferrazzi, Enrico; Figueiró-Filho, Ernesto A; Gaugler-Senden, Ingrid P M; Haavaldsen, Camilla; Lykke, Jacob A; Mbah, Alfred K; Oliveira, Vanessa M; Poston, Lucilla; Redman, Christopher W G; Salim, Raed; Thilaganathan, Baskaran; Vergani, Patrizia; Zhang, Jun; Steegers, Eric A P; Mol, Ben Willem J; Ganzevoort, Wessel

    2015-01-01

    OBJECTIVE: We performed an individual participant data (IPD) metaanalysis to calculate the recurrence risk of hypertensive disorders of pregnancy (HDP) and recurrence of individual hypertensive syndromes. STUDY DESIGN: We performed an electronic literature search for cohort studies that reported on...... increased with decreasing gestational age at delivery in the index pregnancy. If the HDP recurred, in general it was milder, regarding maximum diastolic blood pressure, proteinuria, the use of oral antihypertensive and anticonvulsive medication, the delivery of a small-for-gestational-age child, premature...... delivery, and perinatal death. Normotensive women experienced chronic hypertension after pregnancy more often after experiencing recurrence (odds ratio, 3.7; 95% CI, 2.3-6.1). CONCLUSION: Among women that experience hypertension in pregnancy, the recurrence rate in a next pregnancy is relatively low, and...

  7. Surgical treatment for residual or recurrent strabismus

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2014-12-01

    Full Text Available Although the surgical treatment is a relatively effective and predictable method for correcting residual or recurrent strabismus, such as posterior fixation sutures, medial rectus marginal myotomy, unilateral or bilateral rectus re-recession and resection, unilateral lateral rectus recession and adjustable suture, no standard protocol is established for the surgical style. Different surgical approaches have been recommended for correcting residual or recurrent strabismus. The choice of the surgical procedure depends on the former operation pattern and the surgical dosages applied on the patients, residual or recurrent angle of deviation and the operator''s preference and experience. This review attempts to outline recent publications and current opinion in the management of residual or recurrent esotropia and exotropia.

  8. Recurrence of Gestational Diabetes in Primiparous Women

    DEFF Research Database (Denmark)

    Kruse, Anne Raabjerg; Darling, Mette S.; Hansen, Mia K. L.; Markman, Miriam J.; Lauszus, Finn F.; Wielandt, Hanne B.

    2015-01-01

    women had a subsequent pregnancy and they all attended the recommended screening procedure, a 75-g oral glucose tolerance test at 14–20 (early) or 27–30 (late) weeks' gestation. The recurrence rate of GDM was 47.2%. The risk of recurrence was less in women who lost weight between the first and the...... women and evaluate the factors involved such as age, body mass index, weight gain, time between pregnancy and postpartum OGTT results. Material and methods We established a prospective cohort during a 5-year period at the Department of Obstetrics at Kolding Hospital. Women with diet-treated GDM in their...... subsequent pregnancy. Conclusions Recurrence of diet-treated GDM was 47.2% in primiparous women with previous GDM and the recurrence was associated with weight gain between pregnancies....

  9. Recurrent encephalic hemorrhage associated with cocaine abuse

    International Nuclear Information System (INIS)

    We report a case of recurrent intracerebral hemorrhage secondary to cocaine abuse in a patient with no other predisposing factors. The hemorrhages were located both supra- and infratentorially. (orig.)

  10. Recurrence quantification analysis theory and best practices

    CERN Document Server

    Jr, Jr; Marwan, Norbert

    2015-01-01

    The analysis of recurrences in dynamical systems by using recurrence plots and their quantification is still an emerging field.  Over the past decades recurrence plots have proven to be valuable data visualization and analysis tools in the theoretical study of complex, time-varying dynamical systems as well as in various applications in biology, neuroscience, kinesiology, psychology, physiology, engineering, physics, geosciences, linguistics, finance, economics, and other disciplines.   This multi-authored book intends to comprehensively introduce and showcase recent advances as well as established best practices concerning both theoretical and practical aspects of recurrence plot based analysis.  Edited and authored by leading researcher in the field, the various chapters address an interdisciplinary readership, ranging from theoretical physicists to application-oriented scientists in all data-providing disciplines.

  11. Ocean wave forecasting using recurrent neural networks

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Prabaharan, N.

    , merchant vessel routing, nearshore construction, etc. more efficiently and safely. This paper describes an artificial neural network, namely recurrent neural network with rprop update algorithm and is applied for wave forecasting. Measured ocean waves off...

  12. Mindfulness Therapy May Help Ease Recurrent Depression

    Science.gov (United States)

    ... nlm.nih.gov/medlineplus/news/fullstory_158537.html Mindfulness Therapy May Help Ease Recurrent Depression Review of ... 27, 2016 WEDNESDAY, April 27, 2016 (HealthDay News) -- Mindfulness therapy may help reduce the risk of repeated ...

  13. Is acute recurrent pancreatitis a chronic disease?

    Directory of Open Access Journals (Sweden)

    Alberto Mariani, Pier Alberto Testoni

    2008-02-01

    Full Text Available Whether acute recurrent pancreatitis is a chronic disease is still debated and a consensus is not still reached as demonstrated by differences in the classification of acute recurrent pancreatitis. There is major evidence for considering alcoholic pancreatitis as a chronic disease ab initio while chronic pancreatitis lesions detectable in biliary acute recurrent pancreatitis (ARP seem a casual association. Cystic fibrosis transmembrane conductance regulator (CFTR gene mutation, hereditary and obstructive pancreatitis seem an acute disease that progress to chronic pancreatitis, likely as a consequence of the activation and proliferation of pancreatic stellate cells that produce and activate collagen and therefore fibrosis. From the diagnostic point of view, in patients with acute recurrent pancreatitis Endoscopic ultrasound (EUS seems the more reliable technique for an accurate evaluation and follow-up of some ductal and parenchymal abnormalities suspected for early chronic pancreatitis.

  14. Risk factors that affect recurrence in strokes

    Directory of Open Access Journals (Sweden)

    Sevim Baybaş

    2010-01-01

    Full Text Available Introduction: Recurrent stroke is defined as a new cerebrovascular event which occurs after the stabilization of the previous stroke. Recurrence of stroke increases likelihood of disability-mortality associated with stroke. Systematic evaluation of stroke cases can help to reduce the risk of recurrence. Objective: In order to predict strokes which carry the risk of recurrence, we aimed to compare data related to risk factors, stroke type, etiology and disability-mortality rates associated with stroke. Material And Method: Patients with stroke who referred to Bakırkoy Neurological and Psychiatric Diseases Training and Research State Hospital between June 1, 2002 and February 28, 2003 were recorded into the stroke database in a consecutive and prospective manner. Strokes were classified as ischemic/hemorrhagic and first/recurrent. For recurrent strokes, information about previous strokes was also recorded. Risk factors were classified as hypertension (HT, diabetes mellitus (DM, hyperlipidemia, atrial fibrillation (AF, coronary artery disease (CAD, migraine, transient ischemic accident (TIA, family history of cerebrovascular accident (CVA, oral contraceptive use, PAD, congestive heart failure (CHF, other heart diseases, smoking cigarette and alcohol consumption. Disability-mortality rates associated with stroke were evaluated. All data were compared for first and recurrent strokes. Results: In our study, 631 patients were evaluated, 52.3% of whom were female and 47.7% male. Frequency of stroke was statistically high (p<0.001 in females over 70 years old. Recurrent strokes were of the same type. For the first and recurrent strokes, HT was the highest risk factor. AF frequency increased with age (p<0.001. The rate of disability-mortality was found high in strokes of undetermined and cardioembolic origin. Conclusion: Knowledge of etiologic group can help to predict recurrence of stroke and prevent death. We think that effective treatment of modifiable risk factors identified in stroke groups where recurrence is the highest, and prioritising the investigation of cardioembolic risk factors in elderly women are significant in terms of primary and secondary stroke prevention.

  15. The Sonographic Features of Recurrent Breast Cancer

    International Nuclear Information System (INIS)

    We wanted to evaluate the sonographic findings of recurrent breast cancer in the patients who underwent mastectomy or breast conserving surgery (BCS). We also wanted to evaluate the characteristics of recurrent cancer that's detected on follow up sonography only. We retrospectively reviewed 87 patients with recurrent breast cancer and who were operated on during the previous 10 years. We analyzed the method of detection and the sonographic appearance of tumor, including the location, size, shape, margin, internal echogenicity and BI-RADS categories, in 52 patients who had abnormal sonographic findings. We compared the sonographic findings of the recurrent cancer between the patients who underwent mastectomy and the patients who underwent BCS. We also analyzed the characters of the recurrent cancer that was only detectable on follow-up sonography. Among the 87 patients with recurrent breast cancer, 37 patients had undergone previous mastectomy and 50 patients had undergone previous BCS. The most common mode of detection was a palpable mass on physical examination for the patients who underwent mastectomy (64.9%, 24/37) and the most common mode of detection was the follow-up sonography for the patients who underwent BCS (40%, 20/50). The sonographic appearance of the recurrent cancer was similar for both the patients who underwent mastectomy or BCS. The most common locations were the breast parenchymal layer in 82% (36/44) of the patients who underwent BCS and the subcutaneous fat layer of the operated area in 67% (14/21) of the patients who underwent mastectomy. The type of recurrent cancer detected on sonography only was small nodules in the patients who underwent BCS, and that for the patients who underwent mastectomy was nodules, regardless of size, that were located in the deep muscle layer. Recurrent breast cancer, regardless of size, was frequently detected on a physical examination in the patients who underwent previous mastectomy, and this was detected on sonography in the patients who underwent with previous BCS. Follow up sonography was valuable to evaluate for tumor recurrence after breast cancer surgery, and this detected 16% (6/37), 28% (14/50) of the recurrent cancers that were otherwise occult tumor

  16. Cytogenetic Study in Couples with Recurrent Miscarriage

    OpenAIRE

    Tarek A. Atia, **Salah E. Mourad*** Salem H

    2007-01-01

    Introduction: Recurrent miscarriage (RM) is a mysterious reproductive problem affecting a proportion of couples trying to conceive. Although spontaneous abortion occurs in approximately 15 to 20% of clinically diagnosed pregnancies of reproductive-aged women, recurrent miscarriage occurs in approximately 1 to 2% of these women. Many syndromes are involved in the aetiology of RM, where genetic factors appear to be highly associated. Indeed, chromosomal anomaly constitutes the single most commo...

  17. PET Imaging in Recurrent Medullary Thyroid Carcinoma

    OpenAIRE

    Giorgio Treglia; Vittoria Rufini; Massimo Salvatori; Alessandro Giordano; Luca Giovanella

    2012-01-01

    Purpose. To perform an overview about the role of positron emission tomography (PET) or PET/computed tomography (PET/CT) using different radiopharmaceuticals in recurrent medullary thyroid carcinoma (MTC) based on biochemical findings (increased tumor marker levels after primary surgery). Methods. A comprehensive literature search of studies published in PubMed/MEDLINE, Scopus, and Embase databases through February 2012 regarding PET or PET/CT in patients with recurrent MTC was performed. Res...

  18. Par-4 prevents breast cancer recurrence

    OpenAIRE

    Hebbar, Nikhil; Shrestha-Bhattarai, Tripti; RANGNEKAR, VIVEK M.

    2013-01-01

    Therapy resistance and disease recurrence are two of the most challenging aspects in breast cancer treatment. A recent article in Cancer Cell makes a significant contribution toward a better understanding of this therapeutic problem by establishing downregulation of the tumor suppressor Par-4 as the primary determinant of breast cancer recurrence. This viewpoint brings forth the importance of their findings and its implications on future research and therapy.

  19. Par-4 prevents breast cancer recurrence.

    Science.gov (United States)

    Hebbar, Nikhil; Shrestha-Bhattarai, Tripti; Rangnekar, Vivek M

    2013-01-01

    Therapy resistance and disease recurrence are two of the most challenging aspects in breast cancer treatment. A recent article in Cancer Cell makes a significant contribution toward a better understanding of this therapeutic problem by establishing downregulation of the tumor suppressor Par-4 as the primary determinant of breast cancer recurrence. This viewpoint brings forth the importance of their findings and its implications on future research and therapy. PMID:24164776

  20. Autocorrelation function and quantum recurrence of Wavepackets

    International Nuclear Information System (INIS)

    Quantum wavepackets follow classical orbits and spread initially with time except for the special case when the energy levels are equally spaced, e.g. the harmonic oscillator. However, for integrable systems bound localized wavepackets can exhibit at long times quantum recurrences which do not have a classical correspondence. For the Coulomb potential the recurrence time is approximately n/3 times the Kepler period 2πn3, where n is the mean value of the principal quantum numbers of the wavepacket

  1. Optimizing and Contrasting Recurrent Neural Network Architectures

    OpenAIRE

    Krause, Ben

    2015-01-01

    Recurrent Neural Networks (RNNs) have long been recognized for their potential to model complex time series. However, it remains to be determined what optimization techniques and recurrent architectures can be used to best realize this potential. The experiments presented take a deep look into Hessian free optimization, a powerful second order optimization method that has shown promising results, but still does not enjoy widespread use. This algorithm was used to train to a number of RNN arch...

  2. Surgical Management of Recurrent Nasopharyngeal Carcinoma

    OpenAIRE

    Sheng-Po Hao; Ngan-Ming Tsang

    2010-01-01

    Current standard treatment of nasopharyngeal carcinoma(NPC) is either radiotherapy alone or combined chemoradiotherapy.Surgery in the form of nasopharyngectomy is usuallyonly offered when there is evidence of local recurrence or persistentdisease. Recurrent NPC (rNPC) can be detected earlierwith the utilization of Epstein-Barr virus molecular diagnosis.This may result in early management with salvage surgery andhence improved survival. The facial translocation approachenhanced our ability to ...

  3. Inguinal hernia recurrence: Classification and approach

    OpenAIRE

    Campanelli Giampiero; Pettinari Diego; Cavalli Marta; Avesani Ettore

    2006-01-01

    The authors reviewed the records of 2,468 operations of groin hernia in 2,350 patients, including 277 recurrent hernias updated to January 2005. The data obtained - evaluating technique, results and complications - were used to propose a simple anatomo-clinical classification into three types which could be used to plan the surgical strategy:Type R1: first recurrence ′high,′ oblique external, reducible hernia with small (< 2 cm) defect in non-obese patients, after pure tissu...

  4. Regional phlebography in patients with varicocele recurrences

    International Nuclear Information System (INIS)

    Diagnostic potentialities of phlebography were studies in 50 patients with varicocele recurrences. Two methods of phlebography: transfemoral renospermaticography and transscrotal orthograde testiculophlebography - were employed. The main cause of recurrence development was shown to be the abnormality of venous outflow from the testicle in the region of the left renal vein, testicular vein and in the pelvic veins. The effectiveness of both methods was 71.9 and 94.4%, respectively, their combined use provided additional information

  5. Current surgery of retinal detachment recurrence. Review

    Directory of Open Access Journals (Sweden)

    V. D. Zakharov

    2014-07-01

    Full Text Available this review presents a detailed analysis and an experience of surgical treatment of retinal detachment recurrence associated with light silicone oil tamponade of vitreous cavity. Approaches and variants of treatment were described in the historical aspect and till now. there are considered general and particular issues in case of retinal detachment recurrence appearance, expediency and volume of intraoperative manipulations, time of operation and choice of temporary substitute of vitreous body for a purpose of postoperative tamponade of vitreous cavity.

  6. Family history and recurrence of febrile seizures.

    OpenAIRE

    Van Esch, A; Steyerberg, E.W.; Berger, M. Y.; Offringa, M.; Derksen-Lubsen, G; Habbema, J D

    1994-01-01

    To determine the value of a detailed family history for the assessment of the risk of recurrence of febrile seizures, 115 children who visited the emergency room of an academic children's hospital were studied prospectively. The recurrence risk of febrile seizures was analysed in relation to the child's family history and the proportion of relatives affected by febrile seizures using Kaplan-Meier estimates and Cox proportional hazard models. A first degree family history positive for febrile ...

  7. TODDLER WITH RECURRENT ABDOMINAL PAIN: MIGRAINE?

    OpenAIRE

    Amit; Vaishali

    2014-01-01

    Abdominal migraine is a migraine variant, causing chronic idiopathic recurrent abdominal pain in 4-15% of children. It is usually seen between the ages of seven to twelve years and is more common in girls, with peak prevalence at the age of ten years. We report a 3 year old girl suffering from recurrent abdominal pain since 1½ years of age, who underwent extensive investigations as well as diagnostic laparotomy with appendectomy, and was ultimately diagnosed to have abdomi...

  8. Biopsychosocial model of chronic recurrent pain

    OpenAIRE

    Zlatka Rakovec-Felser; Jernej Vidmar; Rok Holnthaner

    2009-01-01

    Pain is not merely a symptom of disease but a complex independent phenomenon where psychological factors are always present (Sternberg, 1973). Especially by chronic, recurrent pain it's more constructive to think of chronic pain as a syndrome that evolves over time, involving a complex interaction of physiological/organic, psychological, and behavioural processes. Study of chronic recurrent functional pain covers tension form of headache. 50 suffering persons were accidentally chosen ...

  9. Recurrence of breech presentation in consecutive pregnancies

    OpenAIRE

    Ford, JB; Roberts, CL; Nassar, N.; Giles, W; Morris, JM

    2010-01-01

    Objective To investigate the recurrence risk of breech presentation at term, and to assess the risk factors that contribute to its recurrence. Design Cohort study. Setting New South Wales, Australia. Population Women with their first two (n = 113 854) and first three (n = 21 690) consecutive singleton term pregnancies, in the period 1994–2002. Methods Descriptive statistics including rates, relative risks and adjusted relative risks, as determined from logistic regression and Poisson analyses...

  10. Heterogeneous recurrence monitoring and control of nonlinear stochastic processes

    Science.gov (United States)

    Yang, Hui; Chen, Yun

    2014-03-01

    Recurrence is one of the most common phenomena in natural and engineering systems. Process monitoring of dynamic transitions in nonlinear and nonstationary systems is more concerned with aperiodic recurrences and recurrence variations. However, little has been done to investigate the heterogeneous recurrence variations and link with the objectives of process monitoring and anomaly detection. Notably, nonlinear recurrence methodologies are based on homogeneous recurrences, which treat all recurrence states in the same way as black dots, and non-recurrence is white in recurrence plots. Heterogeneous recurrences are more concerned about the variations of recurrence states in terms of state properties (e.g., values and relative locations) and the evolving dynamics (e.g., sequential state transitions). This paper presents a novel approach of heterogeneous recurrence analysis that utilizes a new fractal representation to delineate heterogeneous recurrence states in multiple scales, including the recurrences of both single states and multi-state sequences. Further, we developed a new set of heterogeneous recurrence quantifiers that are extracted from fractal representation in the transformed space. To that end, we integrated multivariate statistical control charts with heterogeneous recurrence analysis to simultaneously monitor two or more related quantifiers. Experimental results on nonlinear stochastic processes show that the proposed approach not only captures heterogeneous recurrence patterns in the fractal representation but also effectively monitors the changes in the dynamics of a complex system.

  11. Heterogeneous recurrence monitoring and control of nonlinear stochastic processes.

    Science.gov (United States)

    Yang, Hui; Chen, Yun

    2014-03-01

    Recurrence is one of the most common phenomena in natural and engineering systems. Process monitoring of dynamic transitions in nonlinear and nonstationary systems is more concerned with aperiodic recurrences and recurrence variations. However, little has been done to investigate the heterogeneous recurrence variations and link with the objectives of process monitoring and anomaly detection. Notably, nonlinear recurrence methodologies are based on homogeneous recurrences, which treat all recurrence states in the same way as black dots, and non-recurrence is white in recurrence plots. Heterogeneous recurrences are more concerned about the variations of recurrence states in terms of state properties (e.g., values and relative locations) and the evolving dynamics (e.g., sequential state transitions). This paper presents a novel approach of heterogeneous recurrence analysis that utilizes a new fractal representation to delineate heterogeneous recurrence states in multiple scales, including the recurrences of both single states and multi-state sequences. Further, we developed a new set of heterogeneous recurrence quantifiers that are extracted from fractal representation in the transformed space. To that end, we integrated multivariate statistical control charts with heterogeneous recurrence analysis to simultaneously monitor two or more related quantifiers. Experimental results on nonlinear stochastic processes show that the proposed approach not only captures heterogeneous recurrence patterns in the fractal representation but also effectively monitors the changes in the dynamics of a complex system. PMID:24697400

  12. Heterogeneous recurrence monitoring and control of nonlinear stochastic processes

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hui, E-mail: huiyang@usf.edu; Chen, Yun [Complex Systems Monitoring, Modeling and Analysis Laboratory, University of South Florida, Tampa, Florida 33620 (United States)

    2014-03-15

    Recurrence is one of the most common phenomena in natural and engineering systems. Process monitoring of dynamic transitions in nonlinear and nonstationary systems is more concerned with aperiodic recurrences and recurrence variations. However, little has been done to investigate the heterogeneous recurrence variations and link with the objectives of process monitoring and anomaly detection. Notably, nonlinear recurrence methodologies are based on homogeneous recurrences, which treat all recurrence states in the same way as black dots, and non-recurrence is white in recurrence plots. Heterogeneous recurrences are more concerned about the variations of recurrence states in terms of state properties (e.g., values and relative locations) and the evolving dynamics (e.g., sequential state transitions). This paper presents a novel approach of heterogeneous recurrence analysis that utilizes a new fractal representation to delineate heterogeneous recurrence states in multiple scales, including the recurrences of both single states and multi-state sequences. Further, we developed a new set of heterogeneous recurrence quantifiers that are extracted from fractal representation in the transformed space. To that end, we integrated multivariate statistical control charts with heterogeneous recurrence analysis to simultaneously monitor two or more related quantifiers. Experimental results on nonlinear stochastic processes show that the proposed approach not only captures heterogeneous recurrence patterns in the fractal representation but also effectively monitors the changes in the dynamics of a complex system.

  13. Heterogeneous recurrence monitoring and control of nonlinear stochastic processes

    International Nuclear Information System (INIS)

    Recurrence is one of the most common phenomena in natural and engineering systems. Process monitoring of dynamic transitions in nonlinear and nonstationary systems is more concerned with aperiodic recurrences and recurrence variations. However, little has been done to investigate the heterogeneous recurrence variations and link with the objectives of process monitoring and anomaly detection. Notably, nonlinear recurrence methodologies are based on homogeneous recurrences, which treat all recurrence states in the same way as black dots, and non-recurrence is white in recurrence plots. Heterogeneous recurrences are more concerned about the variations of recurrence states in terms of state properties (e.g., values and relative locations) and the evolving dynamics (e.g., sequential state transitions). This paper presents a novel approach of heterogeneous recurrence analysis that utilizes a new fractal representation to delineate heterogeneous recurrence states in multiple scales, including the recurrences of both single states and multi-state sequences. Further, we developed a new set of heterogeneous recurrence quantifiers that are extracted from fractal representation in the transformed space. To that end, we integrated multivariate statistical control charts with heterogeneous recurrence analysis to simultaneously monitor two or more related quantifiers. Experimental results on nonlinear stochastic processes show that the proposed approach not only captures heterogeneous recurrence patterns in the fractal representation but also effectively monitors the changes in the dynamics of a complex system

  14. FDG-PET probe-guided surgery for recurrent retroperitoneal testicular tumor recurrences

    OpenAIRE

    Jong, J.S. de; van Ginkel, R.J.; Slart, R.H.J.A.; Lemstra, C.L.; Paans, A.M.J.; Mulder, N. H.; Hoekstra, H.J.

    2010-01-01

    Abstract Aim Tumor marker based recurrences of previously treated testicular cancer are generally detected with CT-scan. They sometimes cannot be visualized with conventional morphologic imaging. FDG-PET has the ability to detect these recurrences. PET probe-guided surgery, may facilitate the extent of surgery and optimize the surgical resection. Methods Three patient with resectable 2nd or 3rd recurrent testicular cancer based on elevated tumor mar...

  15. FSGS Recurrence in Adults after Renal Transplantation

    Science.gov (United States)

    Rudnicki, Michael

    2016-01-01

    Recurrence of focal segmental glomerulosclerosis (FSGS) in the allograft occurs in 30–50% of patients, and it is associated with poor renal allograft survival. Major risk factors for recurrence are younger age at diagnosis, rapid progression to end-stage renal disease, white race, and the loss of previous allografts due to recurrence. Recent data support the hypothesis that circulating permeability factors play a crucial role in podocyte injury and progression of FSGS. Due to lack of controlled trials, the management of recurrent FSGS is inconsistent and highly empirical. Prophylactic and perioperative treatment with plasmapheresis and high-dose (intravenous) cyclosporine represent the main cornerstones of immunosuppressive therapy. In recent years, therapy with rituximab has shown promising results. Despite evidence of activation of the renin-angiotensin system (RAS) in recurrent FSGS and its association with progression, only limited data exist on the renoprotective role of RAS blockade in this setting. Further well designed studies are needed on pathogenesis risk factors and therapeutical options in FSGS and its recurrence after transplantation.

  16. Management of recurrent postoperative fungal endophthalmitis

    Directory of Open Access Journals (Sweden)

    Anand Vinekar

    2014-01-01

    Full Text Available Aim: To report the management of recurrent postoperative fungal endophthalmitis (POFE after failed pars plana vitrectomy (PPV and antifungal therapy. Settings and Design: Tertiary Care Referral Centre in North India. Retrospective, single institution, interventional case-series. Materials and Methods: Six patients with microbiologically proven recurrent post-operative fungal endophthalmitis refractory to conventional management were included. The final recurrence was managed with intraocular lens (IOL explantation and re-PPV. Main outcome measures included preserved globe anatomy, visual acuity and retinal status. ′Anatomical success′ was defined as preserved anatomy of the globe, and absence of signs of inflammation. ′Functional success′ was defined as an attached retina and a best corrected visual acuity of better than 20/400. Results: Of the six cases of POFE, five were culture positive [Aspergillus flavus (1, Aspergillus fumigatus (2, Candida albicans (1 and Candida glabrata (1] and one was smear positive for yeast. All recurred (mean recurrences, 4 despite a mean of 2.17 PPVs and intravitreal amphotericin B. No recurrences were observed after IOL explantation with re - PPV (median follow-up, 37 months. Pre-study defined criteria for successful ′anatomical′ and ′functional′ outcomes were achieved in 83.3% and 50% respectively. Conclusion: This report highlights the effective role of combined IOL explantation with PPV in managing recurrent POFE.

  17. Recurrence relations for spin foam vertices

    International Nuclear Information System (INIS)

    We study recurrence relations for various Wigner 3nj-symbols and the non-topological 10j-symbol. For the 6j- and the 15j-symbols which correspond to basic amplitudes of 3d and 4d topological spin foam models, recurrence relations are obtained from the invariance under Pachner moves and can be interpreted as quantizations of the constraints of the underlying classical field theories. We also derive recurrences from the action of holonomy operators on spin network functionals, making a more precise link between the topological Pachner moves and the classical constraints. Interestingly, our recurrence relations apply to any SU(2) invariant symbol, depending on the cycles of the corresponding spin network graph. Another method is used for non-topological objects such as the 10j-symbol and pseudo-isosceles 6j-symbols. The recurrence relations are also interpreted in terms of elementary geometric properties. Finally, we discuss the extension of the recurrences to take into account boundary states which leads to equations similar to Ward identities for correlation functions in the Barrett-Crane model.

  18. Tactile display with dielectric multilayer elastomer actuatorsq

    Science.gov (United States)

    Matysek, Marc; Lotz, Peter; Schlaak, Helmut F.

    2009-03-01

    Tactile perception is the human sensation of surface textures through the vibrations generated by stroking a finger over the surface. The skin responds to several distributed physical quantities. Perhaps the most important are high-frequency vibrations, pressure distributions (static shape) and thermal properties. The integration of tactile displays in man-machine interfaces promises a more intuitive handling. For this reason many tactile displays are developed using different technologies. We present several state-of-the-art tactile displays based on different types of dielectric elastomer actuators to clarify the advantages of our matrix display based on multilayer technology. Using this technology perpendicular and hexagonal arrays of actuator elements (tactile stimulators) can be integrated into a PDMS substrate. Element diameters down to 1 mm allow stimuli at the range of the human two-point-discrimination threshold. Driving the elements by column and row addressing enables various stimulation patterns with a reduced number of feeding lines. The transient analysis determines charging times of the capacitive actuators depending on actuator geometry and material parameters. This is very important to ensure an adequate dynamic characteristic of the actuators to stimulate the human skin by vibrations. The suitability of multilayer dielectric elastomer actuators for actuation in tactile displays has been determined. Beside the realization of a static tactile display - where multilayer DEA are integrated as drives for movable contact pins - we focus on the direct use of DEA as a vibrotactile display. Finally, we present the scenario and achieved results of a recognition threshold test. Even relative low voltages in the range of 800 V generate vibrations with 100% recognition ratio within the group of participants. Furthermore, the frequency dependent characteristic of the determined recognition threshold confirms with established literature.

  19. Dipole radiation in a multilayer geometry

    International Nuclear Information System (INIS)

    There are several kinds of experiments that can be done with multilayer stacks of dielectric media which require an understanding of light emission by sources within the stack for their analysis. These experiments may involve, for example, light-emitting tunnel junctions, Raman scattering in Kretschmann and other multilayered geometries, and Rayleigh scattering by small amounts of surface or interface roughness, either alone or in combination with other processes. A set of electromagnetic Green's functions for a multilayer stack of isotropic dielectric media [D. L. Mills and A. A. Maradudin, Phys. Rev. B 12, 2943 (1975)] gives the electric fields produced everywhere by a point source of current oscillating at a frequency f. These Green's functions can thus be used to solve this type of problem. In this paper we show how these Green's functions can be written in terms of 2 x 2 transfer matrices of the type commonly used to find the fields in a dielectric stack due to an incident plane wave. With this simplification we can easily evaluate the Green's functions for a stack with an arbitrary number of layers. We further show that, when the electric fields generated by a point source within the stack are evaluated far away, they can be written directly in terms of the electric fields that would be generated at the location of the current source by plane waves incident from the direction of the observation point. We show that this follows from the Lorentz reciprocity theorem. Thus, in this case the formalism of Green's functions is not needed

  20. Ceramic-Metal Interfaces in Multilayer Actuators

    DEFF Research Database (Denmark)

    Engell, John; Pedersen, Henrik Guldberg; Andersen, Bjørn; James, Andrew S.

    1996-01-01

    Multilayer actuators consist of a number of piezoelectric or electrostrictive ceramic layers, separated by thin metal electrodes. Thus, the ceramic-metal interface plays an even more important role than for bulk piezoceramics. The performance and durability of the actuator depends closely on the...... quality and strength of this interface. In the case of a weak ceramic-metal interface, delaminations will occur under severe working conditions.Work has been carried out on a commercial PZT type ceramic and various types of Pt electrode paste. The present study involves characterization of the interface...

  1. Oscillating magnetocaloric effect of a multilayer graphene

    Energy Technology Data Exchange (ETDEWEB)

    Alisultanov, Z. Z., E-mail: zaur0102@gmail.com [Amirkhanov Institute of Physics, Russian Academy of Sciences, Dagestan Science Centre, Makhachkala (Russian Federation); Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Dagestan State University, Makhachkala (Russian Federation); Paixão, L. S.; Reis, M. S. [Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, 24210-346 Niterói, RJ (Brazil)

    2014-12-08

    The oscillating magnetocaloric effect of a multilayer graphene in Bernal and rhombohedral stacking is investigated to extend the previous knowledge of the effect on a single layer graphene. We started from results of a tight-binding model and obtained analytical expressions for the thermodynamic potential and for the entropy change. The last exhibits the same dependence on field and temperature observed for other diamagnetic systems; it oscillates with the inverse magnetic field and presents a maximum value at a given temperature. The amplitude of the oscillating entropy change decreases with the number of layers and the stacking sequence rules the magnetocaloric properties of the system.

  2. Analysis of multi-layer ERBS spectra

    International Nuclear Information System (INIS)

    Highlights: • Electron Rutherford backscattering (ERBS) spectra are presented. • The spectra are fitted based on physical meaningful quantities. • Very consistent results are obtained for spectra taken under different conditions. • This establishes that ERBS can be used to measure film thicknesses. - Abstract: A systematic way of analysis of multi-layer electron Rutherford backscattering spectra is described. The approach uses fitting in terms of physical meaningful parameters. Simultaneous analysis then becomes possible for spectra taken at different incoming energies and measurement geometries. Examples are given to demonstrate the level of detail that can be resolved by this technique

  3. High photovoltage multilayer organic dye photocells

    Energy Technology Data Exchange (ETDEWEB)

    Ke Xiao; Gonzalez, E.R.; Anani, A.; Srinivasan, S.; Appleby, A.J. (Texas A and M Univ., College Station, TX (United States). Texas Engineering Experiment Station)

    1993-02-01

    When mixtures of dyes with close enough characteristic wavelengths were employed in single cell arrangements, the light absorbing capabilities were found to increase, giving rise to enhanced photovoltages. Multilayer-organic dye photocells, which were fabricated, generated a high photovoltage. These photocells were then investigated as photoelectrochemical cells. In a 10 layer cell arrangement of the type SnO[sub 2]/10 mM Phenosafranine + 10 mM Brilliant Cresyl Blue + 0.5 M EDTA/Pt, in optical and electrical series, photovoltages as high as 6.4 V were recorded. The characteristics of the photoelectrochemical processes and the problems of photocurrent generation are discussed. (author)

  4. Engineering aspects of multilayer piezoceramic actuators

    International Nuclear Information System (INIS)

    With the increasing demand for multilayer ceramic chip components a full understanding of the co-firing of ceramics with metal electrodes becomes important. In the present work the processing of a piezoelectric monolithic actuator by stacking and cofiring Ag-Pd electroded tape cast layers was studied. The inter-diffusion and microstructure of the co-fired interface of PZT ferroelectrics and Ag-Pd metal electrode were examined by scanning electron microscopy (SEM) and energy-dispersive microanalysis. No strong structural distortions and interdiffusion were observed at the co-fired ceramic-electrode interface

  5. Magnetic properties of Fe/Tb multilayers

    International Nuclear Information System (INIS)

    Multilayered Fe/Tb samples were prepared under ultrahigh vacuum conditions (p-9 mbar) on kapton substrates. A total of four different samples were prepared. Three of them correspond to a series where the Tb thickness is constant at 26 A and Fe varies from 10 to 30 A. The fourth one is the first of a new series where Tb is 7 A thick and Fe 40 A. The samples were investigated by means of SQUID magnetometry and Moessbauer spectroscopy. All samples show perpendicular magnetic anisotropy at low temperature (4.2 K), but only two of them are able to show it at room temperature

  6. Growth and characterisation of uranium multilayers.

    OpenAIRE

    Springell, R.

    2008-01-01

    This thesis investigates the extents of the 5f-3d and 5f-4f electronic interactions in U/Fe, U/Co and U/Gd thin films, where electronic hybridisation effects are expected to influence the magnetism of the U 5f states. The samples were prepared by DC magnetron sputtering and included niobium buffer and capping layers to instigate crystalline growth and prevent oxidation of the multilayer stack. Layer thicknesses were varied between 5A and 90A with up to 30 bilayer repeats. The majority of the ...

  7. Fracture mechanics parameters of multilayer pipes

    Czech Academy of Sciences Publication Activity Database

    Šestáková, Lucie; Náhlík, Luboš; Hutař, Pavel; Knésl, Zdeněk

    2007-01-01

    Roč. 1, č. 1 (2007), s. 299-306. ISSN 1802-680X. [Výpočtová mechanika 2007. Hrad Nečtiny, 05.11.2007-07.11.2007] R&D Projects: GA ČR GA101/05/0227; GA ČR GD106/05/H008 Institutional research plan: CEZ:AV0Z20410507 Keywords : multilayer pipe s * K-calibration * T- stress * finite element method Subject RIV: JL - Materials Fatigue, Friction Mechanics

  8. Fracture mechanics parameters of multilayer pipes

    Directory of Open Access Journals (Sweden)

    Šestáková L.

    2007-10-01

    Full Text Available Multilayer pipes consisting of different materials are frequently used in praxis because of partial improvement of the properties of pipe systems. To estimate lifetime of these pipes the basic fracture parameters have to be determined. In this work finite element calculations are applied in order to estimate the stress intensity factor K and T-stress values for a new type of non-homogenous C-shape specimen. The application of calculated K and T values to laboratory estimation of fracture toughness and its transferability to real pipe system is discussed.

  9. Engineering aspects of multilayer piezoceramic actuators

    Science.gov (United States)

    Golovnin, V. A.; Kaplunov, I. A.; Ivanova, A. I.; Grechishkin, R. M.

    2013-12-01

    With the increasing demand for multilayer ceramic chip components a full understanding of the co-firing of ceramics with metal electrodes becomes important. In the present work the processing of a piezoelectric monolithic actuator by stacking and cofiring Ag-Pd electroded tape cast layers was studied. The inter-diffusion and microstructure of the co-fired interface of PZT ferroelectrics and Ag-Pd metal electrode were examined by scanning electron microscopy (SEM) and energy-dispersive microanalysis. No strong structural distortions and interdiffusion were observed at the co-fired ceramic-electrode interface.

  10. Interface stress in Au/Ni multilayers

    DEFF Research Database (Denmark)

    Schweitz, K.O.; Böttiger, J.; Chevallier, J.; Feidenhans'l, Robert Krarup; Nielsen, Martin Meedom; Rasmussen, Frank Berg

    2000-01-01

    The effect of intermixing on the apparent interface stress is studied in < 111 >-textured dc-magnetron sputtered Au/Ni multilayers by use of two methods commonly used for determining interface stress. The method using profilometry and in-plane x-ray diffraction does not take intermixing into...... inapplicable to interface stress determinations in systems exhibiting a modulation period-dependent stress-free lattice parameter. Finally, a deviation of the interface stress in the Au/Ni sample with the smallest modulation period as compared to specimens with larger bilayer lengths is observed to be...

  11. Optics and multilayer coatings for EUVL systems

    Energy Technology Data Exchange (ETDEWEB)

    Soufli, R; Bajt, S; Hudyma, R M; Taylor, J S

    2008-03-21

    EUV lithography (EUVL) employs illumination wavelengths around 13.5 nm, and in many aspects it is considered an extension of optical lithography, which is used for the high-volume manufacturing (HVM) of today's microprocessors. The EUV wavelength of illumination dictates the use of reflective optical elements (mirrors) as opposed to the refractive lenses used in conventional lithographic systems. Thus, EUVL tools are based on all-reflective concepts: they use multilayer (ML) coated optics for their illumination and projection systems, and they have a ML-coated reflective mask.

  12. Swift ion irradiation of magnetostrictive multilayers

    International Nuclear Information System (INIS)

    The modification of the magnetic and magnetostrictive properties of TbFe2/Co exchange-coupled multilayers irradiated with 700 MeV Pb ions was investigated as a function of ion fluence. After irradiation, the magnetostrictive properties of the sample are first strongly improved up to a fluence of 1 x 1012 ions cm-2 where the magnetoelastic susceptibility is six times higher than for the as-deposited sample. This effect is ascribed to stress relaxation and Fe-Co intermixing at the interfaces. For higher fluences, the magnetostrictive properties do not vary further, indicating a stationary state of mixing

  13. An evaluation of factors predicting breast recurrence and prognosis after recurrence, on distinguishing intramammary and extramammary recurrence, in breast-conserving surgery

    International Nuclear Information System (INIS)

    Recurrence of cancer in the breast is an important problem in breast-conserving therapy. We evaluated risk factors for recurrence from the viewpoint of recurrence type and outcome after recurrence. Of 533 cases of breast cancer treated with breast-conserving surgery from April 1989 through July 2000, disease in 66 recurred (12.4%) and were classified as 23 cases of breast recurrence only, 16 cases of both breast recurrence and distant metastasis, and 27 cases of distant metastasis only. The clinical factors examined included age, lymphatic invasion, nodal status, extensive intraductal component (EIC), proliferative activity, and estrogen receptor (ER) status. Of the 39 cases of breast recurrence, 19 had intramammary tumors and 20 had extramammary tumors of the skin, subcutaneous tissue, or muscle, including 8 cases with inflammatory breast recurrence. Multivariate analysis showed that factors correlated with breast recurrence were age, ER status, proliferative activity, and surgical margin. EIC-comedo was related to intramammary recurrence, whereas lymphatic invasion and nodal status were related to extramammary recurrence. Postoperative irradiation was an effective treatment for tumors in young women and tumors with positive margins or a comedo component. Outcome after breast recurrence depended on nodal status at primary operation, and survival rates were worst in patients with inflammatory breast recurrence. In conclusion, age, EIC-comedo status, the surgical margin, and negative ER status were correlated with breast recurrence. Countermeasures against these factors should be investigated. (author)

  14. An evaluation of factors predicting breast recurrence and prognosis after recurrence, on distinguishing intramammary and extramammary recurrence, in breast-conserving surgery

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Reiki; Nagao, Kazuharu; Miyayama, Haruhiko [Kumamoto City Hospital (Japan)] (and others)

    2001-06-01

    Recurrence of cancer in the breast is an important problem in breast-conserving therapy. We evaluated risk factors for recurrence from the viewpoint of recurrence type and outcome after recurrence. Of 533 cases of breast cancer treated with breast-conserving surgery from April 1989 through July 2000, disease in 66 recurred (12.4%) and were classified as 23 cases of breast recurrence only, 16 cases of both breast recurrence and distant metastasis, and 27 cases of distant metastasis only. The clinical factors examined included age, lymphatic invasion, nodal status, extensive intraductal component (EIC), proliferative activity, and estrogen receptor (ER) status. Of the 39 cases of breast recurrence, 19 had intramammary tumors and 20 had extramammary tumors of the skin, subcutaneous tissue, or muscle, including 8 cases with inflammatory breast recurrence. Multivariate analysis showed that factors correlated with breast recurrence were age, ER status, proliferative activity, and surgical margin. EIC-comedo was related to intramammary recurrence, whereas lymphatic invasion and nodal status were related to extramammary recurrence. Postoperative irradiation was an effective treatment for tumors in young women and tumors with positive margins or a comedo component. Outcome after breast recurrence depended on nodal status at primary operation, and survival rates were worst in patients with inflammatory breast recurrence. In conclusion, age, EIC-comedo status, the surgical margin, and negative ER status were correlated with breast recurrence. Countermeasures against these factors should be investigated. (author)

  15. Multiperiodicity in plasmonic multilayers: General description and diversity of topologies

    DEFF Research Database (Denmark)

    Orlov, Alexey A.; Krylova, Anastasia K.; Zhukovsky, Sergei; Babicheva, Viktoriia; Belov, Pavel A.

    2014-01-01

    We introduce multiperiodicity in periodicmetal-dielectric multilayers by stacking more than two types of metal and/or dielectric layers into the unit cell. A simple way to characterize arbitrary multiperiodic multilayers using permutation vectors is suggested and employed. Effects of...

  16. Novel polyelectrolyte multilayer micro- and nanocapsules as magnetic carriers

    International Nuclear Information System (INIS)

    Polyelectrolyte multilayer (PEM) capsules are introduced as versatile magnetic carrier systems. Superparamagnetic magnetite is mounted to the multilayer shell itself or is a component of the capsule interior. The PEM is formed at different (decomposable) colloidal templates, e.g. melamine formaldehyde resin, glutaraldehyde fixed red blood cells, emulsion oil droplets. The results are illustrated by transmission electron microscopy and confocal laser scanning microscopy

  17. Propagation of Acoustic Waves in Liquid Containing Multilayer Barrier

    International Nuclear Information System (INIS)

    The dynamics of acoustic waves in a liquid containing multilayer barrier is studied. Using the subroutine of the fast Fourier transform the calculation of the distortion of the acoustic signal at the diagnosis of a multilayer sample comprising a layer of a liquid with polydispersed bubbles is executed. A good agreement between theoretical and experimental data is obtained

  18. High-Density Stretchable Electronics: Toward an Integrated Multilayer Composite

    OpenAIRE

    Guo, Liang; DeWeerth, Stephen P.

    2010-01-01

    High-density stretchable electronics is achieved using multilayer interconnects on an elastomeric substrate. Two major challenges associated with stretchable electronics—increasing integration density and improving electrical bonding—have been addressed by our innovative multilayer via-bonding technology. The resulting multichip-module architecture provides an elastic, high-density solution for numerous potential applications.

  19. Multi-layer laminate structure and manufacturing method

    Science.gov (United States)

    Keenihan, James R.; Cleereman, Robert J.; Eurich, Gerald; Graham, Andrew T.; Langmaid, Joe A.

    2013-01-29

    The present invention is premised upon a multi-layer laminate structure and method of manufacture, more particularly to a method of constructing the multi-layer laminate structure utilizing a laminate frame and at least one energy activated flowable polymer.

  20. Magnetostrictive properties of Kr-ion irradiated multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Grenier, A. [Groupe de Physique des Materiaux, UMR CNRS 6634, Universite de Rouen, 76801 Saint Etienne du Rouvray (France); Juraszek, J. [Groupe de Physique des Materiaux, UMR CNRS 6634, Universite de Rouen, 76801 Saint Etienne du Rouvray (France)]. E-mail: jean.juraszek@univ-rouen.fr; Tiercelin, N. [Groupe de Physique des Materiaux, UMR CNRS 6634, Universite de Rouen, 76801 Saint Etienne du Rouvray (France); Teillet, J. [IEMN-UMR 8520, Avenue poincare, BP 69, 59652 Villeneuve d' Ascq cedex (France); Toulemonde, M. [Laboratoire CIRIL, GANIL-Boulevard H. Becquerel, BP5133, 14070 Caen Cedex 5 (France); Le Breton, J.M. [Groupe de Physique des Materiaux, UMR CNRS 6634, Universite de Rouen, 76801 Saint Etienne du Rouvray (France)

    2007-03-15

    The influence of irradiation with high energy Kr ions has been experimentally studied on the magnetostrictive properties of TbFe/Co multilayers. Enhancement of magnetostriction at saturation can be obtained at an optimal fluence with a lower saturation field than for the non-irradiated multilayer. For high fluences, these properties are degraded.