Algorithm for Training a Recurrent Multilayer Perceptron
Parlos, Alexander G.; Rais, Omar T.; Menon, Sunil K.; Atiya, Amir F.
2004-01-01
An improved algorithm has been devised for training a recurrent multilayer perceptron (RMLP) for optimal performance in predicting the behavior of a complex, dynamic, and noisy system multiple time steps into the future. [An RMLP is a computational neural network with self-feedback and cross-talk (both delayed by one time step) among neurons in hidden layers]. Like other neural-network-training algorithms, this algorithm adjusts network biases and synaptic-connection weights according to a gradient-descent rule. The distinguishing feature of this algorithm is a combination of global feedback (the use of predictions as well as the current output value in computing the gradient at each time step) and recursiveness. The recursive aspect of the algorithm lies in the inclusion of the gradient of predictions at each time step with respect to the predictions at the preceding time step; this recursion enables the RMLP to learn the dynamics. It has been conjectured that carrying the recursion to even earlier time steps would enable the RMLP to represent a noisier, more complex system.
KLASIFIKASI WEBSITE MENGGUNAKAN ALGORITMA MULTILAYER PERCEPTRON
Directory of Open Access Journals (Sweden)
Nyoman Purnama
2014-08-01
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%.
Optoelectronic implementation of multilayer perceptron and Hopfield neural networks
Domanski, Andrzej W.; Olszewski, Mikolaj K.; Wolinski, Tomasz R.
2004-11-01
In this paper we present an optoelectronic implementation of two networks based on multilayer perceptron and the Hopfield neural network. We propose two different methods to solve a problem of lack of negative optical signals that are necessary for connections between layers of perceptron as well as within the Hopfield network structure. The first method applied for construction of multilayer perceptron was based on division of signals into two channels and next to use both of them independently as positive and negative signals. The second one, applied for implementation of the Hopfield model, was based on adding of constant value for elements of matrix weight. Both methods of compensation of lack negative optical signals were tested experimentally as optoelectronic models of multilayer perceptron and Hopfield neural network. Special configurations of optical fiber cables and liquid crystal multicell plates were used. In conclusion, possible applications of the optoelectronic neural networks are briefly discussed.
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.
A Parallel Framework for Multilayer Perceptron for Human Face Recognition
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 ...
Learning of Multilayer Perceptrons with Piecewise-Linear Activation Functions.
Czech Academy of Sciences Publication Activity Database
Kozub, P.; Hole?a, Martin
Praha : Matfyzpress, 2008 - (Obdržálek, D.; Štanclová, J.; Plátek, M.), s. 27-46 ISBN 978-80-7378-076-0. [MIS 2008. Malý informatický seminá? /25./. Josef?v d?l (CZ), 12.01.2008-19.01.2008] R&D Projects: GA ?R GA201/08/0802; GA ?R 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
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
International Nuclear Information System (INIS)
A comparative study of powers of multidimensional classifiers on the basis of integral nonparametric goodness-off-fit criteria ?nk and multilayer perceptrons was carried out in the cases where investigated distributions present simultaneous measurements of the same physical values in some detectors of experimental set-up. With the help of a numerical experiment it has been shown that multilayer perceptron provides the power close to limit if the identification of events is carried out in the space of effective variables. A procedure of transformation to such variables is described. Recommendations for the joint usage of the ?nk criteria and multilayer perceptrons are given. (author). 29 refs.; 15 figs
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
Classification of fused face images using multilayer perceptron neural network
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...
Inversion of Self Potential Anomalies with Multilayer Perceptron Neural Networks
Kaftan, Ilknur; S?nd?rg?, Petek; Akdemir, Özer
2014-08-01
This study investigates the inverse solution on a buried and polarized sphere-shaped body using the self-potential method via multilayer perceptron neural networks (MLPNN). The polarization angle ( ?), depth to the centre of sphere ( h), electrical dipole moment ( K) and the zero distance from the origin ( x 0) were estimated. For testing the success of the MLPNN for sphere model, parameters were also estimated by the traditional Damped Least Squares (Levenberg-Marquardt) inversion technique (DLS). The MLPNN was first tested on a synthetic example. The performance of method was also tested for two S/N ratios (5 % and 10 %) by adding noise to the same synthetic data, the estimated model parameters with MLPNN and DLS method are satisfactory. The MLPNN also applied for the field data example in ?zmir, Urla district, Turkey, with two cross-section data evaluated by MLPNN and DLS, and the two methods showed good agreement.
Optical proximity correction using a multilayer perceptron neural network
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.
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
DEFF Research Database (Denmark)
Proud, Simon Richard
2015-01-01
A multilayer perceptron neural network cloud mask for Meteosat Second Generation SEVIRI (Spinning Enhanced Visible and Infrared Imager) images is introduced and evaluated. The model is trained for cloud detection on MSG SEVIRI daytime data. It consists of a multi-layer perceptron with one hidden 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 ?m) 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 and clear sky. The network was further evaluated using sixty MSG images taken at different dates. The network detected not only bright thick clouds but also thin or less bright clouds. The analysis demonstrated the feasibility of using machine learning models of cloud detection in MSG SEVIRI imagery.
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 ?R 1ET100300419 Institutional research plan: CEZ:AV0Z10300504 Keywords : perceptron networks * learning * evolutionary algorithms Subject RIV: IN - Informatics, Computer Science
Orozco-Monteagudo, Maykel; Taboada-Crispi, Alberto; Gutiérrez-Hernández, Liliana
2008-11-01
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.
Experts Fusion and Multilayer Perceptron Based on Belief Learning for Sonar Image Classification
Martin, Arnaud; Osswald, Christophe
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 ...
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.
Directory of Open Access Journals (Sweden)
Alireza Taravat
2015-02-01
Full Text Available A multilayer perceptron neural network cloud mask for Meteosat Second Generation SEVIRI (Spinning Enhanced Visible and Infrared Imager images is introduced and evaluated. The model is trained for cloud detection on MSG SEVIRI daytime data. It consists of a multi-layer perceptron with one hidden 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 ?m 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 and clear sky. The network was further evaluated using sixty MSG images taken at different dates. The network detected not only bright thick clouds but also thin or less bright clouds. The analysis demonstrated the feasibility of using machine learning models of cloud detection in MSG SEVIRI imagery.
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
Multilayered perceptron neural networks to compute energy losses in magnetic cores
Energy Technology Data Exchange (ETDEWEB)
Kucuk, Ilker [Physics Department, Faculty of Arts and Sciences, Uludag University, Gorukle Campus 16059, Bursa (Turkey)]. E-mail: ikucuk@uludag.edu.tr
2006-12-15
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.
Mohammad Fathian,; Arash N.Kia
2012-01-01
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 ac...
Ouadfeul, S.; Aliouane, L.; Tourtchine, V.
2013-09-01
In this paper, a tentative of geomagnetic storms prediction is implanted by analyzing the International Real-Time Magnetic Observatory Network data using the Artificial Neural Network (ANN). The implanted method is based on the prediction of future horizontal geomagnetic field component using a Multilayer Perceptron (MLP) neural network model. The input is the time and the output is the X and Y magnetic field components. Application to geomagnetic data of Mai 2002 shows that the implanted ANN model can greatly help the geomagnetic storms prediction.
Multilayered perceptron neural networks to compute energy losses in magnetic cores
Kucuk, Ilker
2006-12-01
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.
Training multilayer perceptron classifiers based on a modified support vector method.
Suykens, J K; Vandewalle, J
1999-01-01
In this paper we describe a training method for one hidden layer multilayer perceptron classifier which is based on the idea of support vector machines (SVM's). An upper bound on the Vapnik-Chervonenkis (VC) dimension is iteratively minimized over the interconnection matrix of the hidden layer and its bias vector. The output weights are determined according to the support vector method, but without making use of the classifier form which is related to Mercer's condition. The method is illustrated on a two-spiral classification problem. PMID:18252586
Experts Fusion and Multilayer Perceptron Based on Belief Learning for Sonar Image Classification
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.
Neural Networks for Gas Turbine Fault Identification: Multilayer Perceptron or Radial Basis Network?
Loboda, Igor; Feldshteyn, Yakov; Ponomaryov, Volodymyr
2012-03-01
Efficiency of gas turbine condition monitoring systems depends on quality of diagnostic analysis at all its stages such as feature extraction (from raw input data), fault detection, fault identification, and prognosis. Fault identification algorithms based on the gas path analysis may be considered as an important and sophisticated component of these systems. These algorithms widely use pattern recognition techniques, mostly different artificial neural networks. In order to choose the best technique, the present paper compares two network types: a multilayer perceptron and a radial basis network. The first network is being commonly applied to recognize gas turbine faults. However, some studies note high recognition capabilities of the second network. For the purpose of the comparison, both networks were included into a special testing procedure that computes for each network the true positive rate that is the probability of a correct diagnosis. Networks were first tuned and then compared using this criterion. Same procedure input data were fed to both networks during the comparison. However, to draw firm conclusions on the networks' applicability, comparative calculations were repeated with different variations of these data. In particular, two engines that differ in an application and gas path structure were chosen as a test case. By way of summing up comparison results, the conclusion is that the radial basis network is a little more accurate than the perceptron, however the former needs much more available computer memory and computation time.
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
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.
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 ?m 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.
Kalamatianos, Dimitrios; Liatsis, Panos; Wellstead, Peter E
2006-01-01
Near-infrared (NIR) spectroscopy is being applied to the solution of problems in many areas of biomedical and pharmaceutical research. In this paper we investigate the use of NIR spectroscopy as an analytical tool to quantify concentrations of urea, creatinine, glucose and oxyhemoglobin (HbO2). Measurements have been made in vitro with a portable spectrometer developed in our labs that consists of a two beam interferometer operating in the range of 800-2300 nm. For the data analysis a pattern recognition philosophy was used with a preprocessing stage and a multi-layer perceptron (MLP) neural network for the measurement stage. Results show that the interferogram signatures of the above compounds are sufficiently strong in that spectral range. Measurements of three different concentrations were possible with mean squared error (MSE) of the order of 10(-6). PMID:17947035
Classification of Polar-Thermal Eigenfaces using Multilayer Perceptron for Human Face Recognition
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%.
Übeyli, Mustafa; Übeyli, Elif Derya
2008-12-01
Artificial neural networks (ANNs) have recently been utilized in the nuclear technology applications since they are fast, precise and flexible vehicles to modeling, simulation and optimization. This paper presents a new approach based on multilayer perceptron neural networks (MLPNNs) for the estimation of some important neutronic parameters (net 239Pu production, tritium breeding ratio, cumulative fissile fuel enrichment, and fission rate) of a high power density fusion-fission (hybrid) reactor using light water reactor (LWR) spent fuel. A comparison of the results obtained by the MLPNNs and those found by using the code (Scale 4.3) was carried out. The results pointed out that the MLPNNs trained with least mean squares (LMS) algorithm could provide an accurate computation of the main neutronic parameters for the high power density reactor.
Cousseau, Florent; Mimura, Kazushi; Okada, Masato
2010-02-01
An error correcting code using a treelike multilayer perceptron is proposed. An original message s0 is encoded into a codeword y0 using a treelike committee machine (committee tree) or a treelike parity machine (parity tree). Based on these architectures, several schemes featuring monotonic or nonmonotonic units are introduced. The codeword y0 is then transmitted via a binary asymmetric channel where it is corrupted by noise. The analytical performance of these schemes is investigated using the replica method of statistical mechanics. Under some specific conditions, some of the proposed schemes are shown to saturate the Shannon bound at the infinite codeword length limit. The influence of the monotonicity of the units on the performance is also discussed. PMID:20365527
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.
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)
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
Su, Feng-Chun; Ho, Chung-Ru; Kuo, Nan-Jung
2005-01-01
The multilayer perceptron (MLP) neural network have been widely used to fit non-linear transfer function and performed well. In this study, we use MLP to estimate chlorophyll-a concentrations from marine reflectance measures. The optical data were assembled from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Bio-optical Algorithm Mini-workshop (SeaBAM). Most bio-optical algorithms use simple ratios of reflectance in blue and green bands or combinations of ratios as parameters for regression analysis. Regression analysis has limitations for nonlinear function. Neural network, however, have been shown better performance for nonlinear problems. The result showed that accuracy of chlorophyll-a concentration using MLP is much higher than that of regression method. Nevertheless, using all of the five bands as input can derive the best performance. The results showed that each band could carry some useful messages for ocean color remote sensing. Only using band ratio (OC2) or band switch (OC4) might lose some available information. By preprocessing reflectance data with the principle component analysis (PCA), MLP could derive much better accuracy than traditional methods. The result showed that the reflectance of all bands should not be ignored for deriving the chlorophyll-a concentration because each band carries different useful ocean color information.
Tfwala, Samkele S; Wang, Yu-Min; Lin, Yu-Chieh
2013-01-01
Hydrological data are often missing due to natural disasters, improper operation, limited equipment life, and other factors, which limit hydrological analysis. Therefore, missing data recovery is an essential process in hydrology. This paper investigates the accuracy of artificial neural networks (ANN) in estimating missing flow records. The purpose is to develop and apply neural networks models to estimate missing flow records in a station when data from adjacent stations is available. Multilayer perceptron neural networks model (MLP) and coactive neurofuzzy inference system model (CANFISM) are used to estimate daily flow records for Li-Lin station using daily flow data for the period 1997 to 2009 from three adjacent stations (Nan-Feng, Lao-Nung and San-Lin) in southern Taiwan. The performance of MLP is slightly better than CANFISM, having R (2) of 0.98 and 0.97, respectively. We conclude that accurate estimations of missing flow records under the complex hydrological conditions of Taiwan could be attained by intelligent methods such as MLP and CANFISM. PMID:24453876
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.
Cross Validation Evaluation for Breast Cancer Prediction Using Multilayer Perceptron Neural Networks
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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.
Vanzella, E.; Cristiani, S.; Fontana, A.; Nonino, M.; Arnouts, S.; Giallongo, E.; Grazian, A.; Fasano, G.; Popesso, P.; Saracco, P.; Zaggia, S.
2004-08-01
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
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%.
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
International Nuclear Information System (INIS)
Highlights: • Multilayer perceptrons are used to simulate the I–V 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 I–V 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 I–V curve to the measured one and the peak power point estimation
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.
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
Sarakhs branch; Sarakhs, Iran.
2012-01-01
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 app...
Sun, Zhongchang; Guo, Huadong; Li, Xinwu; Lu, Linlin; Du, Xiaoping
2011-01-01
In recent years, the urban impervious surface has been recognized as a key quantifiable indicator in assessing urbanization impacts on environmental and ecological conditions. A surge of research interests has resulted in the estimation of urban impervious surface using remote sensing studies. The objective of this paper is to examine and compare the effectiveness of two algorithms for extracting impervious surfaces from Landsat TM imagery; the multilayer perceptron neural network (MLPNN) and the support vector machine (SVM). An accuracy assessment was performed using the high-resolution WorldView images. The root mean square error (RMSE), the mean absolute error (MAE), and the coefficient of determination (R2) were calculated to validate the classification performance and accuracies of MLPNN and SVM. For the MLPNN model, the RMSE, MAE, and R2 were 17.18%, 11.10%, and 0.8474, respectively. The SVM yielded a result with an RMSE of 13.75%, an MAE of 8.92%, and an R2 of 0.9032. The results indicated that SVM performance was superior to that of MLPNN in impervious surface classification. To further evaluate the performance of MLPNN and SVM in handling the mixed-pixels, an accuracy assessment was also conducted for the selected test areas, including commercial, residential, and rural areas. Our results suggested that SVM had better capability in handling the mixed-pixel problem than MLPNN. The superior performance of SVM over MLPNN is mainly attributed to the SVM's capability of deriving the global optimum and handling the over-fitting problem by suitable parameter selection. Overall, SVM provides an efficient and useful method for estimating the impervious surface.
Kaftan, Ilknur; Sindirgi, Petek
2013-04-01
Self-potential (SP) is one of the oldest geophysical methods that provides important information about near-surface structures. Several methods have been developed to interpret SP data using simple geometries. This study investigated inverse solution of a buried, polarized sphere-shaped self-potential (SP ) anomaly via Multilayer Perceptron Neural Networks ( MLPNN ). The polarization angle ( ? ) and depth to the centre of sphere ( h )were estimated. The MLPNN is applied to synthetic and field SP data. In order to see the capability of the method in detecting the number of sources, MLPNN was applied to different spherical models at different depths and locations.. Additionally, the performance of MLPNN was tested by adding random noise to the same synthetic test data. The sphere model successfully obtained similar parameters under different S/N ratios. Then, MLPNN method was applied to two field examples. The first one is the cross section taken from the SP anomaly map of the Ergani-Süleymanköy (Turkey) copper mine. MLPNN was also applied to SP data from Seferihisar Izmir (Western Turkey) geothermal field. The MLPNN results showed good agreement with the original synthetic data set. The effect of The technique gave satisfactory results following the addition of 5% and 10% Gaussian noise levels. The MLPNN results were compared to other SP interpretation techniques, such as Normalized Full Gradient (NFG), inverse solution and nomogram methods. All of the techniques showed strong similarity. Consequently, the synthetic and field applications of this study show that MLPNN provides reliable evaluation of the self potential data modelled by the sphere model.
Directory of Open Access Journals (Sweden)
Sanong Amaroek
2010-01-01
Full Text Available Problem statement: Estimation of moisture contents of dried food products from their dielectric constants was an important step in moisture measurement systems. The regression models that provide good prediction performance are desirable. Approach: The Multilayer Perceptrons (MLP and Support Vector Regression (SVR were applied in this research to predict the moisture contents of dried longan arils from their dielectric constants. The data set was collected from 1500 samples of dried longan aril with five different moisture contents of 10, 14, 18, 22 and 25% Wet basis (Wb. Dielectric constant of dried longan aril was measured by using our previously proposed electrical capacitance-based system. The results from the MLP and SVR models were compared to that from the linear regression and polynomial regression models. To take into account the generalization of the models, the four-fold cross validation was applied. Results: For the training sets, the average mean absolute errors over three bulk densities of 1.30, 1.45 and 1.60 g cm-3 were 1.7578, 0.6157, 0.3812, 0.3113, 0.0103 and 0.0044% Wb for the linear regression, second-, third-, fourth-order polynomial regression, MLP and SVR models, respectively. For the validation sets, the average mean absolute errors over the three bulk densities were 1.7616, 0.6192, 0.3844, 0.3146, 0.0126 and 0.0093% Wb for the linear regression, 2nd, 3rd and 4th-order polynomial regression, MLP and SVR models, respectively. Conclusion: The regression models based on MLP and SVR yielded better performances than the models based on linear regression and polynomial regression on both training and validation sets. The models based on MLP and SVR also provided robustness to the variation of bulk density. Not only for dried longan aril, the proposed models can also be adapted and applied to other materials or dried food products.
Kucuk, Nil; Manohara, S. R.; Hanagodimath, S. M.; Gerward, L.
2013-05-01
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.
DEFF Research Database (Denmark)
Kucuk, Nil; Manohara, S.R.
2013-01-01
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 0.015–15MeV, 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.
Scientific Electronic Library Online (English)
Héctor, Tabares; John, Branch; Jaime, Valencia.
2006-09-01
Full Text Available En este trabajo se aplica un método constructivo aproximado para encontrar arquitecturas de redes neuronales artificiales (RNA) de tipo perceptrón multicapa (PMC). El método se complementa con la técnica de la búsqueda forzada de mejores mínimos locales. El entrenamiento de la red se lleva a cabo a [...] través del algoritmo gradiente descendente básico (GDB); se aplican técnicas como la repetición del entrenamiento y la detención temprana (validación cruzada), para mejorar los resultados. El criterio de evaluación se basa en las habilidades de aprendizaje y de generalización de las arquitecturas generadas específicas de un dominio. Se presentan resultados experimentales con los cuales se demuestra la efectividad del método propuesto y comparan con las arquitecturas halladas por otros métodos. Abstract in english This paper deals with an approximate constructive method to find architectures of artificial neuronal network (ANN) of the type MultiLayer Percetron (MLP) which solves a particular problem. This method is supplemented with the technique of the Forced search of better local minima. The training of th [...] e net uses an algorithm basic descending gradient (BDG). Techniques such as repetition of the training and the early stopping (cross validation) are used to improve the results. The evaluation approach is based not only on the learning abilities but also on the generalization of the specific generated architectures of a domain. Experimental results are presented in order to prove the effectiveness of the proposed method. These are compared with architectures found by other methods.
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
Directory of Open Access Journals (Sweden)
Mokhtar Attari
2013-03-01
Full Text Available 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 Description Language. The classifier relies on a multilayer neural network based on a back propagation algorithm with one hidden layer of four neurons and eight neurons at the input and five neurons at the output. The neural network designed after implementation consists of twenty thousand gates. The achieved experimental results seem to show the effectiveness of the proposed classifier, which can discriminate between five industrial gases.
Scientific Electronic Library Online (English)
Rodrigo Martins da, Silva; Luiza de Macedo, Mourelle; Nadia, Nedjah.
2011-12-01
Full Text Available Em termos computacionais, uma rede neural artificial (RNA) pode ser implementada em software ou em hardware, ou ainda de maneira híbrida, combinando ambos os recursos. O presente trabalho propõe uma arquitetura de hardware para a computação de uma rede neural do tipo perceptron com múltiplas camadas [...] (MLP). Soluções em hardware tendem a ser mais eficientes do que soluções em software. O projeto em questão, além de explorar fortemente o paralelismo das redes neurais, permite alterações do número de entradas, número de camadas e de neurônios por camada, de modo que diversas aplicações de RNAs possam ser executadas no hardware proposto. Visando a uma redução de tempo do processamento aritmético, um número real é aproximado por uma fração de inteiros. Dessa forma, as operações aritméticas limitam-se a operações inteiras, executadas por circuitos combinacionais. Uma simples máquina de estados é demandada para controlar somas e produtos de frações. A função de ativação usada neste projeto é a sigmóide. Essa função é aproximada mediante o uso de polinômios, cujas operações são regidas por somas e produtos. Um teorema é introduzido e provado, permitindo a fundamentação da estratégia de cálculo da função de ativação. Dessa forma, reaproveita-se o circuito aritmético da soma ponderada para também computar a sigmóide. Essa re-utilização dos recursos levou a uma redução drástica de área total de circuito. Após modelagem e simulação para validação do bom funcionamento, a arquitetura proposta foi sintetizada utilizando recursos reconfiguráveis, do tipo FPGA. Os resultados são promissores. Abstract in english There are several neural network implementations using either software, hardware-based or a hardware/software co-design. This work proposes a hardware architecture to implement an artificial neural network (ANN), whose topology is the multilayer perceptron (MLP). In this paper, we explore the parall [...] elism of neural networks and allow on-thefly changes of the number of inputs, number of layers and number of neurons per layer of the net. This reconfigurability characteristic permits that any application of ANNs may be implemented using the proposed hardware. In order to reduce the processing time that is spent in arithmetic computation, a real number is represented using a fraction of integers. In this way, the arithmetics is limited to integer operations, performed by fast combinational circuits. A simple state machine is required to control sums and products of fractions. Sigmoid is used as the activation function in the proposed implementation. It is approximated by polynomials, whose underlying computation requires only sums and products. A theorem is introduced and proven so as to cover the arithmetic strategy of the computation of the activation function. Thus, the arithmetic circuitry used to implement the neuron weighted sum is reused for computing the sigmoid. this resource sharing decreased drastically the total area of the system. After modeling and simulation for functionality validation, the proposed architecture synthesized using reconfigurable hardware. The results are promising.
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.
Scientific Electronic Library Online (English)
Haydeé Elena, Musso; Orlando José, Ávila Blas.
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 p [...] resentaban 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. Abstract in english 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 behavi [...] our, 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.
Scientific Electronic Library Online (English)
Carlos A., de Luna-Ortega; Miguel, Mora-González; Julio C., Martínez-Romo; Francisco J., Luna-Rosas; Jesús, Muñoz-Maciel.
Full Text Available En el presente artículo se da a conocer una alternativa algorítimica a los sistemas actuales de reconocimiento automático del habla (ASR), mediante una propuesta en la forma de realizar la caracterización de las palabras basada en una aproximación que usa la extracción de coeficientes de la codifica [...] ción de predicción lineal (LPC) y la correlación cruzada. La implementación consiste en extraer las características fonéticas mediante los coeficientes LPC, después se forman vectores de patrones de la pronunciación conformados por el promedio de los coeficientes LPC de las muestras de las palabras obteniendo un vector característico de cada pronunciación mediante la autocorrelación de las secuencias de coeficientes LPC; estos vectores se utilizan para entrenar un clasificador de tipo perceptrón multicapa (MLP). Se realizaron pruebas de desempeño previo entrenamiento con los diferentes patrones de las palabras a reconocer. Se utilizó la fonética de los dígitos del cero al nueve como vocabulario objetivo, debido a su amplia aplicación, y para estimar el desempeño de este método se utilizaron dos corpus de pronunciaciones: el corpus UPA, que contempla en su base de datos la pronuncación de la región occidente de México, y el corpus Tlatoa, que hace lo propio para la región centro de México. Las señales en ambos corpus fueron adquiridas en el lenguaje español, y a una frecuencia de muestreo de 8kHz. Los porcentajes de reconocimiento obtenidos fueron del 96.7 y 93.3% para las modalidades de mono-locutor para el corpus UPA y múltiple-locutor para el corpus Tlatoa, respectivamente. Asimismo, se realizó una comparación contra dos métodos clásicos del reconocimiento de voz y del habla, Dynamic Time Warping (DTW) y Hidden Markov Models (HMM). Abstract in english It this paper we present an algorithmic alternative to the current Automatic Speech Recognition (ASR) systems by proposing a way to characterize words based on approximations that use an extracted coefficient from Linear Predictive Coding (LPC). The method consists in extracting phonetic characteris [...] tics through the use of LPC coefficients, after which pattern vectors are formed from the LPC coefficient averages taken from the word sampling, thus creating a unique vector for each pronunciation through the auto correlation of the LPC coefficient sequences. These vectors are used to train a Multilayer Perceptron (MLP) classifier. After training performance trials were executed. The sounds from the digits zero through nine where used as a target vocabulary, given its general use, and to estimate the performance of this method two corpus where used: the UPA corpus, which in its vocabulary uses a pronunciation familiar to the western part of Mexico, and the Tlatoa corpus, who's vocabulary presents a pronunciation typical of the central region of Mexico. The signals from both corpus where sampled in the Spanish language, and at a sampling frequency of 8kHz. The recognition rate for the mono-speaker from the UPA corpus and the multiple-speaker from the Tlatoa corpus were 96.7% and 93.3% respectively. Additionally, there where comparisons done against two classic methods used for speech recognition, Dynamic Time Warping (DTW) and Hidden Markov Models (HMM).
Scientific Electronic Library Online (English)
Yuleidys, Mejías César; Ramón, Carrasco Velar; Isbel, Ochoa Izquierdo; Edel, Moreno Lemus.
2013-12-01
Full Text Available El perceptrón multicapa (PMC) figura dentro de los tipos de redes neuronales artificiales (RNA) con resultados útiles en los estudios de relación estructura-actividad. Dado que los volúmenes de datos en proyectos de Bioinformática son eventualmente grandes, se propuso evaluar algoritmos para acortar [...] el tiempo de entrenamiento de la red sin afectar su eficiencia. Se desarrolló 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 perceptrón multicapa. Se demostró que en dependencia de la muestra de entrenamiento, la variación de las funciones de transferencia pueden reportar resultados mucho más eficientes que los obtenidos con la clásica función Sigmoidal, con incremento de la g-media entre el 4.5 y el 17 %. Se encontró además 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.
Scientific Electronic Library Online (English)
José C, Cúrvelo Santana; Sidnei A, de Araújo; 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) Perceptrón Multicapa (PMC) para simular la variación de la concentración de proteína de acuerdo con el tiempo y también para determinar la hora final del procedimiento, además de los parámetros óptimos del proceso de biodegradació [...] n de las proteínas de un efluente de matadero. Para eso, han sido utilizadas las papaínas, presentes en el látex de la papaya (Carica papaya) con el objetivo de disminuir la concentración de proteínas de un efluente de matadero a pH (5 y 7) con una temperatura de (25 y 30° C) controlada. Los resultados mostraron que las papaínas redujeron de 82% a 91% la concentración de proteína 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 reducción de 91% de la concentración de proteínas. 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.
Scientific Electronic Library Online (English)
Alejandro J., Orozco-Naranjo; Pablo A., Muñoz-Gutiérrez.
2013-12-30
Full Text Available Este artículo presenta los resultados obtenidos al desarrollar una metodología para la detección de 5 tipos de latidos cardiacos (Normal (N), Bloqueo de Rama Derecha (RBBB), Bloqueo de Rama Izquierda (LBBB), Contracción Auricular Prematura (APC) y Contracción Ventricular Prematura (PVC)) utilizando [...] la transformada por paquetes Wavelet de manera no adaptativa en la extracción de características de las señales cardiacas, empleando la función Shanon para cálculo de la entropía y adicionando una fase de identificación de nodos por cada tipo de señal cardiaca en el árbol Wavelet. La utilización de la transformada por paquetes Wavelet permite acceder a información obtenida de la descomposición tanto de baja como de alta frecuencia proporcionando un análisis más integral que el logrado con la transformada Wavelet discreta. Se evaluaron Wavelets madre de las familias Daubechies, Symlet 5 y Biortogonal inversa; que fueron resultado de una investigación previa en que se identificaron las Wavelet madre que mayor entropía presentaban con las señales cardiacas. Con la modalidad no adaptativa se reduce el costo computacional al utilizar los paquetes Wavelet, coste que representa la mayor desventaja de esta transformada, dando validez a la investigación realizada. Para la clasificación de los patrones cardiacos se emplearon las máquinas de soporte vectorial y el perceptrón multicapa. Con las máquinas de soporte vectorial empleando kernel de función de base radial, se logró un error de clasificación del 2,57 %. Abstract in english 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 n [...] on-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 %.
Fault characterization of a multilayered perceptron network
Tan, Chang H.; Iyer, Ravishankar K.
1990-01-01
The results of a set of simulation experiments conducted to quantify the effects of faults in a classification network implemented as a three-layered perception model are reported. The percentage of vectors misclassified by the classification network, the time taken for the network to stabilize, and the output values are measured. The results show that both transient and permanent faults have a significant impact on the performance of the network. Transient faults are also found to cause the network to be increasingly unstable as the duration of a transient is increased. The average percentage of the vectors misclassified is about 25 percent; after relearning, this is reduced to 10 percent. The impact of link faults is relatively insignificant in comparison with node faults (1 percent versus 19 percent misclassified after relearning). A study of the impact of hardware redundancy shows a linear increase in misclassifications with increasing hardware size.
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 Evolutionary Computation. Singapore (SG), 25.09.2007-28.09.2007] R&D Projects: GA AV ?R 1ET100300419 Institutional research plan: CEZ:AV0Z10300504 Keywords : hybrid algorithm s * evolutionary learning * neural networks Subject RIV: IN - Informatics, Computer Science
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
Classification of fuels using multilayer perceptron neural networks
Ozaki, Sérgio T. R.; Wiziack, Nadja K. L.; Paterno, Leonardo G.; Fonseca, Fernando J.
2009-05-01
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.
Parallel strategy for optimal learning in perceptrons
International Nuclear Information System (INIS)
We developed a parallel strategy for learning optimally specific realizable rules by perceptrons, in an online learning scenario. Our result is a generalization of the Caticha-Kinouchi (CK) algorithm developed for learning a perceptron with a synaptic vector drawn from a uniform distribution over the N-dimensional sphere, so called the typical case. Our method outperforms the CK algorithm in almost all possible situations, failing only in a denumerable set of cases. The algorithm is optimal in the sense that it saturates Bayesian bounds when it succeeds.
Minimization of Error Functionals over Perceptron Networks.
Czech Academy of Sciences Publication Activity Database
K?rková, V?ra
2008-01-01
Ro?. 20, ?. 1 (2008), s. 252-270. ISSN 0899-7667 R&D Projects: GA ?R GA201/05/0557 Institutional research plan: CEZ:AV0Z10300504 Keywords : model complexity of perceptron networks * minimization of error functionals Subject RIV: BA - General Mathematics Impact factor: 2.378, year: 2008
A diluted version of the perceptron model
Marquez-Carreras, D; Tindel, S; Marquez-Carreras, David; Rovira, Carles; Tindel, Samy
2006-01-01
This note is concerned with a diluted version of the perceptron model. We establish a replica symmetric formula at high temperature, which is achieved by studying the asymptotic behavior of a given spin magnetization. Our main task will be to identify the order parameter of the system.
Best Approximation by Heaviside Perceptron Networks.
Czech Academy of Sciences Publication Activity Database
Kainen, P.C.; K?rková, V?ra; Vogt, A.
2000-01-01
Ro?. 13, ?. 7 (2000), s. 695-697. ISSN 0893-6080 R&D Projects: GA ?R GA201/96/0917; GA AV ?R IAA2030602 Institutional research plan: AV0Z1030915 Keywords : one-hidden-layer networks * heaviside perceptrons * best approximation * metric projection * continuous selection * approximatively compact Subject RIV: BA - General Mathematics Impact factor: 1.221, year: 2000
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)
Simulating a perceptron on a quantum computer
Schuld, Maria; Sinayskiy, Ilya; Petruccione, Francesco
2014-01-01
Perceptrons are the basic computational unit of artificial neural networks, as they model the activation mechanism of an output neuron due to incoming signals from its neighbours. As linear classifiers, they play an important role in the foundations of machine learning. In the context of the emerging field of quantum machine learning, several attempts have been made to develop a corresponding unit using quantum information theory. Based on the quantum phase estimation algori...
Landscape statistics of the binary perceptron
Fontanari, J.F.; Köberle, R.
1990-01-01
The landscape of the binary perceptron is studied by Simulated Annealing, exhaustive search and performing random walks on the landscape. We find that the number of local minima increases exponentially with the number of bonds, becoming deeper in the vicinity of a global minimum, but more and more shallow as we move away from it. The random walker detects a simple dependence on the size of the mapping, the architecture introducing a nontrivial dependence on the number of steps.
Learning algorithms for perceptrons from statistical physics
Gordon, Mirta; Peretto, Pierre; Berchier, Dominique
1993-01-01
Learning algorithms for perceptrons are deduced from statistical mechanics. Thermodynamical quantities are used as cost functions which may be extremalized by gradient dynamics to find the synaptic efficacies that store the learning set of patterns. The learning rules so obtained are classified in two categories, following the statistics used to derive the cost functions, namely, Boltzmann statistics, and Fermi statistics. In the limits of zero or infinite temperatures some of the rules behav...
Multifractal analysis of perceptron learning with errors
Weigt, M
1998-01-01
Random input patterns induce a partition of the coupling space of a perceptron into cells labeled by their output sequences. Learning some data with a maximal error rate leads to clusters of neighboring cells. By analyzing the internal structure of these clusters with the formalism of multifractals, we can handle different storage and generalization tasks for lazy students and absent-minded teachers within one unified approach. The results also allow some conclusions on the spatial distribution of cells.
Minimization of Empirical Error over Perceptron Networks.
Czech Academy of Sciences Publication Activity Database
K?rková, V?ra
Wien : Springer-Verlag, 2005 - (Ribiero, B.; Albrecht, R.; Dobnikar, A.; Pearson, D.; Steele, N.), s. 46-49 ISBN 3-211-24934-6. [ICANNGA'2005 /7./. Coimbra (PT), 21.03.2005-23.03.2005] R&D Projects: GA ?R GA201/05/0557 Institutional research plan: CEZ:AV0Z10300504 Keywords : supervised learning * perceptron networks * approximate optimization Subject RIV: BA - General Mathematics
Representations of Boolean Functions by Perceptron Networks.
Czech Academy of Sciences Publication Activity Database
K?rková, V?ra
Prague : Institute of Computer Science AS CR, 2014 - (K?rková, V.; Bajer, L.; Peška, L.; Vojtáš, R.; Hole?a, 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 network s * model complexity * Boolean functions Subject RIV: IN - Informatics, Computer Science
Generalization ability of a multilayer neural network
Inoue, J; Kabashima, Yoshiyuki; Inoue, Jun-ichi; Nishimori, Hidetoshi; Kabashima, Yoshiyuki
1998-01-01
We investigate the generalization ability of a perceptron with non-monotonic transfer function of a reversed-wedge type in on-line mode. This network is identical to a parity machine, a multilayer network. We consider several learning algorithms. By the perceptron algorithm the generalization error is shown to decrease by the ${\\alpha}^{-1/3}$-law similarly to the case of a simple perceptron in a restricted range of the parameter $a$ characterizing the non-monotonic transfer function. For other values of $a$, the perceptron algorithm leads to the state where the weight vector of the student is just opposite to that of the teacher. The Hebbian learning algorithm has a similar property; it works only in a limited range of the parameter. The conventional AdaTron algorithm does not give a vanishing generalization error for any values of $a$. We thus introduce a modified AdaTron algorithm which yields a good performance for all values of $a$. We also investigate the effects of optimization of the learning rate as ...
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...
Stability of the replica symmetric solution in diluted perceptron learning
Lage-Castellanos, Alejandro; Pagnani, Andrea; Angulo, Gretel Quintero
2012-01-01
We study the role played by the 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 $\\alpha$ between the number of patterns M and the dimension N of the perceptron ($\\alpha=M/N$), there exists a critical d...
Replica calculation of the Vapnik-Chervonenkis bound for the perceptron
Engel, A.; Van den Broeck, C.
1993-11-01
Using the replica technique, we calculate the maximum difference between test and generalization error for the ensemble of all perceptrons trained by a teacher perceptron. The result is compared with the bound provided by the Vapnik-Chervonenkis theorem.
Multifractals and percolation in the coupling space of perceptrons
Weigt, M
1996-01-01
The coupling space of perceptrons with continuous as well as with binary weights gets partitioned into a disordered multifractal by a set of $p=\\gamma N$ random input patterns. The multifractal spectrum $f(\\alpha)$ can be calculated analytically using the replica formalism. The storage capacity and the generalization behaviour of the perceptron are shown to be related to properties of $f(\\alpha)$ which are correctly described within the replica symmetric ansatz. Replica symmetry breaking is interpreted geometrically as a transition from percolating to non-percolating cells. The existence of empty cells gives rise to singularities in the multifractal spectrum. The relation of these singularities to the Vapnik-Chervonenkis-dimension of the perceptron is discussed. The analytical results for binary couplings are corroborated by numerical studies.
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 ? between the number of patterns M and the dimension N of the perceptron (? = M/N), there exists a critical dilution field hc above which the replica symmetric ansatz becomes unstable. (letter)
Vapnik-Chervonenkis entropy of the spherical perceptron
Riegler, P.; Seung, H. S.
1997-03-01
Perceptron learning of randomly labeled patterns is analyzed using a Gibbs distribution on the set of realizable labelings of the patterns. The entropy of this distribution is an extension of the Vapnik-Chervonenkis (VC) entropy, reducing to it exactly in the limit of infinite temperature. The close relationship between the VC and Gardner entropies can be seen within the replica formalism.
Scientific Electronic Library Online (English)
F., Dall Cortivo; E. S., Chalhoub; H. F., Campos Velho.
2012-12-01
Full Text Available Estimativa do perfil de concentração de clorofila, em águas naturais, a partir da radiação emergente na superfície de um corpo d'agua, com o uso de rede neural artificial do tipo Perceptron de Múltiplas Camadas. A concentração de clorofila está relacionada com os coeficientes de absorção e espalhame [...] nto via modelos bio-ópticos. O treinamento da rede é formulado como um problema de otimização, no qual a atualização das variáveis livres da rede (pesos, viés e parâmetros de cada função de ativação) é feita através do método quasi-Newton. Abstract in english In this work the average profile of chlorophyll concentration is estimated from the emitted radiation at the surface of natural waters. This is performed through the use an Artificial Neural Network of Multilayer Perceptron type to act as the inverse operator. Bio-optical models are used to correlat [...] e the chlorophyll concentration with the absorption and scattering coefficients. The network training is formulated as an optimization problem, in which the update of the free variables of network (weights, viéses and each slope of the activation functions) is performed through the quasi-Newton method.
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...
The Role of Weight Shrinking in Large Margin Perceptron Learning
Panagiotakopoulos, Constantinos
2012-01-01
We introduce into the classical perceptron algorithm with margin a mechanism that shrinks the current weight vector as a first step of the update. If the shrinking factor is constant the resulting algorithm may be regarded as a margin-error-driven version of NORMA with constant learning rate. In this case we show that the allowed strength of shrinking depends on the value of the maximum margin. We also consider variable shrinking factors for which there is no such dependence. In both cases we obtain new generalizations of the perceptron with margin able to provably attain in a finite number of steps any desirable approximation of the maximal margin hyperplane. The new approximate maximum margin classifiers appear experimentally to be very competitive in 2-norm soft margin tasks involving linear kernels.
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.)
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.)
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
Spectral peak verification and recognition using a multilayered neural network.
Wythoff, B J; Levine, S P; Tomellini, S A
1990-12-15
The verification and recognition of peak-shaped signals in analytical data are ubiquitous scientific problems. Experimental data contain overlapping signals and noise, which make sensitive and reliable peak recognition difficult. A peak detection system based on a class of neural networks known as "multilayered perceptrons" has been created. The network was trained and evaluated with use of vapor-phase infrared spectral data. The results of varying the network architecture on system training and prediction performance along with refinement of the form of the input pattern are presented. PMID:2096735
Representations of highly-varying functions by perceptron networks.
Czech Academy of Sciences Publication Activity Database
K?rková, V?ra
North Charleston : CreateSpace Independent Publishing Platform, 2013 - (Vina?, T.; Hole?a, 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 ?R GAP202/11/1368 Institutional support: RVO:67985807 Keywords : one-hidden-layer network s * perceptrons * Boolean functions * network complexity Subject RIV: IN - Informatics, Computer Science
FORECASTING ON FOREX MARKET WITH RBF AND PERCEPTRON NEURAL NETWORKS
Directory of Open Access Journals (Sweden)
ALEXANDRA KOTTILOVÁ
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
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
Djerfaf, F.; Vincent, D.; Robert, S.; Merzouki, A.
2011-12-01
A novel characterization method using artificial neural networks is presented. This method allows one to determine the intrinsic permeability tensor of ferrite thin-films from S-parameters measurements. Neural networks, efficient to solve inverse problems, are used to compute the permeability tensor components ? and k. This optimization technique is used to find extremely complex functions between inputs and outputs and can be successfully applied on our magnetic thin-film characterization problem. Results of our networks are compared to a theoretical model. A great number of both simulated and measured tests have been performed on many magnetic thin-films. Neural network processing leads to a rapid and robust method for predicting the magnetic characterization of thin-films in microwave range.
Entropy landscape of solutions in the binary perceptron problem
International Nuclear Information System (INIS)
The statistical picture of the solution space for a binary perceptron is studied. The binary perceptron learns a random classification of input random patterns by a set of binary synaptic weights. The learning of this network is difficult especially when the pattern (constraint) density is close to the capacity, which is supposed to be intimately related to the structure of the solution space. The geometrical organization is elucidated by the entropy landscape from a reference configuration and of solution-pairs separated by a given Hamming distance in the solution space. We evaluate the entropy at the annealed level as well as replica symmetric level and the mean field result is confirmed by the numerical simulations on single instances using the proposed message passing algorithms. From the first landscape (a random configuration as a reference), we see clearly how the solution space shrinks as more constraints are added. From the second landscape of solution-pairs, we deduce the coexistence of clustering and freezing in the solution space. (paper)
Engel, A.; van den Broeck, C.
1993-09-01
The generalization abilities of neural networks for inferring a rule on the basis of examples can be characterized by the convergence of the learning error to the generalization error with increasing size of the training set. Using the replica technique, we calculate the maximum difference between training and generalization error for the ensemble of all perceptrons trained by a teacher perceptron and the maximal generalization error for the perceptrons that have a training error equal to zero. The results are compared with the rigorous bounds provided by the Vapnik-Chervonenkis theorem.
Handwritten Arabic Numeral Recognition using a Multi Layer Perceptron
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....
Object classifiction with recurrent feedback neural networks
Achler, Tsvi
2007-04-01
We present a mathematical model of interacting neuron- like units that we call Recurrent Feedback Neuronal Networks (RFNN). Our model is closer to biological neural networks than current approaches (e.g. Layered Neural Networks, Perceptron, etc.). Classification and reasoning in RFNN are accomplished by an iterative algorithm, and learning changes only structure (weights are fixed in RFNN). Thus it emphasizes network structure over edge weights. RFNNs are more flexible and scalable than previous approaches. In particular, integration of a new node can affect the outcome of existing nodes without modifying their prior structure. RFNN can produce informative responses to partial inputs or when the networks are extended to other tasks. It also enables recognition of complex entities (e.g. images) from parts. This new model is promising for future contributions to integrated human-level intelligent applications due to its flexibility, dynamics and structural similarity to natural neuronal networks.
Intelligent control of HVAC systems. Part II: perceptron performance analysis
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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.
Multilayer networks: Dangerous liaisons?
Bianconi, Ginestra
2014-10-01
Many networks interact with one another by forming multilayer networks, but these structures can lead to large cascading failures. The secret that guarantees the robustness of multilayer networks seems to be in their correlations.
Multilayer diffraction grating properties
Erko, A.; Martynov, V.; Roshchoupkin, D.; Yuakshin, A.; Vidal, B (Borja); Vincent, P.; Brunel, M
1994-01-01
In the paper the diffraction properties of multilayer static and dynamic gratings are discussed using reciprocal space and dispersive surfaces representation. A strong dependence of the multilayer grating properties on the lamellar period and the optical characteristics of multilayer grating materials are shown. Important points in the grating fabrication, computer simulation, and tests also described.?
Perceptron-like computation based on biologically-inspired neurons with heterosynaptic mechanisms
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.
Isomorphisms in Multilayer Networks
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.
On the Vapnik-Chervonenkis dimension of the Ising-perceptron
Mertens, S
1996-01-01
The VC dimension of the Ising perceptron with binary patterns is calculated by numerical enumerations for system sizes N <= 31. It is significantly larger than N/2. The data suggest that there is probably no well defined asymptotic behaviour for N to infinity.
LETTER TO THE EDITOR: On the Vapnik - Chervonenkis dimension of the Ising perceptron
Mertens, S.
1996-04-01
The Vapnik - Chervonenkis (VC) dimension of the Ising perceptron with binary patterns is calculated by numerical enumerations for system sizes 0305-4470/29/8/004/img1. It is significantly larger than 0305-4470/29/8/004/img2. The data suggest that there is probably no well-defined asymptotic behaviour for 0305-4470/29/8/004/img3.
Efficient routing on multilayered communication networks
Zhou, Jie; Lai, Choy-Heng; 10.1209/0295-5075/102/28002
2013-01-01
We study the optimal routing on multilayered communication networks, which are composed of two layers of subnetworks. One is a wireless network, and the other is a wired network. We develop a simple recurrent algorithm to find an optimal routing on this kind of multilayered network, where the single-channel transmission mode and the multichannel transmission mode used on the wireless subnetwork are considered, respectively. Compared with the performance of the shortest path algorithm, our algorithm can significantly enhance the transport capacity. We show that our methods proposed in this letter could take advantage of the coupling of the two layers to the most extent, so that the wireless subnetwork could sufficiently utilize the wired subnetwork for transportation.
Efficient routing on multilayered communication networks
Zhou, Jie; Yan, Gang; Lai, Choy-Heng
2013-04-01
We study the optimal routing on multilayered communication networks, which are composed of two layers of subnetworks. One is a wireless network, and the other is a wired network. We develop a simple recurrent algorithm to find an optimal routing on this kind of multilayered networks, where the single-channel transmission mode and the multichannel transmission mode used on the wireless subnetwork are considered, respectively. Compared with the performance of the shortest path algorithm, our algorithm can significantly enhance the transport capacity. We show that our methods proposed in this letter could take advantage of the coupling of the two layers to the most extent, so that the wireless subnetwork could sufficiently utilize the wired subnetwork for transportation.
Perfect transmission and highly asymmetric light localization in photonic multilayers
International Nuclear Information System (INIS)
General principles for the existence of perfect transmission resonances in photonic multilayer structures are formulated in terms of light interference described by recurrent Airy formulas. Mirror symmetry in the multilayer is shown to be a sufficient but not necessary condition for perfect transmission resonances. Asymmetric structures displaying perfect transmission in accordance with the proposed principles are demonstrated. A hybrid Fabry-Perot photonic-crystal structure of the type (BA)k(AB)k(AABB)m is proposed, combining perfect transmission and highly asymmetric electric field localization. Strength and asymmetry of localization can be controlled independently to be of use in tailoring nonreciprocal behavior of nonlinear all-optical diodes.
Full Text Available Resources Brochures & Videos Resource Links Books & Periodicals Cancer Centers print email Resources » Brochures & Videos Dealing with Recurrence We know that the topic of recurrence in cancer patients can be ...
Full Text Available Resources Brochures & Videos Resource Links Books & Periodicals Cancer Centers print email Resources » Brochures & Videos Dealing with Recurrence We know that the topic of recurrence in cancer patients can be an overwhelming ...
Full Text Available Resources Brochures & Videos Resource Links Books & Periodicals Cancer Centers print email Resources » Brochures & Videos Dealing with Recurrence We know that the topic of recurrence in cancer patients ...
Multilayer dielectric diffraction gratings
Perry, Michael D. (Livermore, CA); Britten, Jerald A. (Oakley, CA); Nguyen, Hoang T. (Livermore, CA); Boyd, Robert (Livermore, CA); Shore, Bruce W. (Livermore, CA)
1999-01-01
The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described.
TAG, dynamic programming, and the perceptron for efficient, feature-rich parsing
Carreras Pérez, Xavier; Collins, Michael; Koo, Terry
2008-01-01
We describe a parsing approach that makes use of the perceptron algorithm, in conjunction with dynamic programming methods, to recover full constituent-based parse trees. The formalism allows a rich set of parse-tree features, including PCFGbased features, bigram and trigram dependency features, and surface features. A severe challenge in applying such an approach to full syntactic parsing is the efficiency of the parsing algorithms involved. We show that efficient training is feasible, using...
Analysis of ensemble learning using simple perceptrons based on online learning theory
Miyoshi, Seiji; Hara, Kazuyuki; Okada, Masato
2004-01-01
Ensemble learning of $K$ nonlinear perceptrons, which determine their outputs by sign functions, is discussed within the framework of online learning and statistical mechanics. One purpose of statistical learning theory is to theoretically obtain the generalization error. This paper shows that ensemble generalization error can be calculated by using two order parameters, that is, the similarity between a teacher and a student, and the similarity among students. The different...
Recurrent zosteriform herpes simplex
Inamadar Arun; Yatgiri R
1992-01-01
A 25-year-old man had recurrent zosteriform herpes simplex for past 6 years. The attacks were precipitated by prolonged exposure to sunlight. Pain was mild and lesions used to subside each time in about 7 days. Clinical features which help in differentiating recurrent herpes simplex from recurrent herpes zoster are summarized.
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.
Control of Multilayer Networks
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.
Singh S; Singh Sanjay; Pandey S
1998-01-01
A case of recurrent pityriasis rosea in a 25-year old man is reported. He had his first attack 4 years ago and new outbreaks followed every year in winter with last 2 episodes occurring in the same year. All investigations were normal and no explanation for recurrences was found.
Directory of Open Access Journals (Sweden)
Singh S
1998-01-01
Full Text Available A case of recurrent pityriasis rosea in a 25-year old man is reported. He had his first attack 4 years ago and new outbreaks followed every year in winter with last 2 episodes occurring in the same year. All investigations were normal and no explanation for recurrences was found.
International Nuclear Information System (INIS)
Diffusion experiments are usually performed at macroscopic length scales, use of multilayers can lower these scale down to the nanometer range. This paper describes the main idea governing atomic transport at such short distance and in such inhomogeneous systems. The basic experimental methods involved are also discussed. Some representative recent works are shortly described
Energy Technology Data Exchange (ETDEWEB)
Piecuch, M.
1988-10-01
Diffusion experiments are usually performed at macroscopic length scales, use of multilayers can lower these scale down to the nanometer range. This paper describes the main idea governing atomic transport at such short distance and in such inhomogeneous systems. The basic experimental methods involved are also discussed. Some representative recent works are shortly described.
Piecuch, M.
1988-01-01
Diffusion experiments are usually performed at macroscopic length scales, use of multilayers can lower these scale down to the nanometer range. This paper describes the main idea governing atomic transport at such short distance and in such inhomogeneous systems. The basic experimental methods involved are also discussed. Some representative recent works are shortly described.
Investigation of periodic multilayers
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.
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 coe?cients 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.
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 ??0.63 for pattern length N = 101 and ??0.41 for N = 1001. If in addition a relearning process is exploited, the learning performance is further improved to a storage capacity of ??0.80 for N = 101 and ??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 ? of the learning task; at a fixed value of ?, the width of the Hamming distance distribution decreases with N
Treatment of recurrent craniopharyngiomas
International Nuclear Information System (INIS)
One of the most common complications of craniopharyngioma treatment is recurrence. The outcomes of treatment for recurrent tumors with different modalities were evaluated. Of the 61 patients treated initially, 24 had recurrence during follow-up period (1-29 years, mean 11 years). Twenty-two patients underwent a total of 35 additional operations for recurrence. With reoperation, total surgical removal was achieved for four occasions (Group A), subtotal resection was achieved with 31 surgical procedures. Nineteen procedures (Group B) were done without radiotherapy and seven were followed by radiotherapy (Group C). Seven patients were treated with radiosurgery (Group D) with or without surgical resection. The surgical mortality rate for Group A was 50% which was higher than for initial operation, while for Group B 10.5% and none for Groups C and D. Good functional status was maintained at follow-up in 50% of survived patients for Group A, 14% for Group B, 57% for Group C and 86% for Group D. The 5-year recurrence free survival rate was 50% for Group A, 16% for Group B, 80% for Group C, and 83.3% for Group D. The rate of recurrence free survival for Group B was significantly lower than Group C (P=0.004) and Group D (P=0.001). The recurrence free survival rates were higher for Groups C and D than for Group B. The mortality and morbidity higher in the Group A. Radiotherapy and radiosurgery are useful adjuncts for the treatment of recurrence, resulting in a high recurrent-free survival rate with better functional outcome. (author)
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
Recurrent partial hydatidiform mole.
Barut, Aykut; Arikan, Iker; Harma, Muge; Harma, Mehmeet Ibrahim; Barut, Figen; Coskan, Ahmet
2011-10-01
Hydatidiform moles are abnormal conceptions characterised by atypical hyperplastic trophoblasts and hydropic villi. Their incidence is approximately 1 in 1000 pregnancies. The recurrence risk of hydatidiform mole is approximately 1 in 60 in a subsequent pregnancy and 1 in 6.5 in the third pregnancy. In cases with recurrence, the majority of moles are of the same type as that in the preceding pregnancy. Here, we describe the case of a recurrent partial hydatidiform mole after an initial healthy pregnancy. Both pregnancies were evacuated by suction curettage, and the patient was followed by serial monitoring of beta-human chorionic gonadotropin levels. Recurrent molar pregnancy is not an indication for chemotherapy, and subsequent pregnancies do not have an increased risk for other obstetric complications. PMID:22356040
Recurrent Urinary Bladder Paraganglioma
Ali A. Al-Zahrani
2010-01-01
A 39-year-old male presented with recurrent attacks of painless haematuria. The patient has a history of partial cystectomy for bladder paraganglioma 10 years prior to the presentation. Imaging study and cystoscopic examination revealed a small anterior wall bladder tumor. The histological examination of the lesion confirmed that it was a urinary paraganglioma. Partial cystectomy was performed to this recurrent lesion. This case report stresses the importance of life-long follow-up of these l...
Mobile Multilayer IPsec protocol
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T.Gayathri
2009-08-01
Full Text Available A mobile user moves around and switches between wireless cells, subnets and domains, it needs to maintain the session continuity. At the same time security of signaling and transport media should not be compromised. A multi-layer security framework involving user authentication, packet based encryption and access control mechanism can provide the desired level of security to the mobile users. Supporting streaming traffic in a mobile wireless Internet is faced with several challenges due to continuous handoff experienced by a mobile user. These challenges include dynamic binding, location management, quality of service and end-to-end security for signaling and transport. Mobile users will use heterogeneous radio access networking technologies. Mobile multilayer IPsec protocol (MML IPSec extends ML-IPSec to deal with mobility and make it suitable for wireless networks. MML-IPSec is integration of ML-IPSec and mobile IP.
Mobile Multilayer IPsec protocol
T. Gayathri; S.Venkadajothi; S. Kalaivani; C. Divya; Dr.C. Suresh Gnana Dhas
2009-01-01
A mobile user moves around and switches between wireless cells, subnets and domains, it needs to maintain the session continuity. At the same time security of signaling and transport media should not be compromised. A multi-layer security framework involving user authentication, packet based encryption and access control mechanism can provide the desired level of security to the mobile users. Supporting streaming traffic in a mobile wireless Internet is faced with several challenges due to co...
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
Kabashima, Yoshiyuki
2007-01-01
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.
Beyond Bragg mirrors: the design of aperiodic omnidirectional multilayer reflectors
International Nuclear Information System (INIS)
A new method that enables omnidirectional reflectivity for all polarizations of incident light over a wide selectable range of wavelengths was used to design aperiodic multilayer mirrors. Choosing the materials, and with the desired threshold value of the reflection coefficient also being given, the resulting reflectors work for all polarizations in a predetermined range of incidence angles and wavelengths. They are 1D photonic aperiodic crystals composed of a stack of layers arranged according to a deterministic aperiodic substitutive sequence appropriately determined. In the calculation of the optical multilayer properties with the Rayleigh-Abeles matrices, the use of the computationally efficient building block recurrence or trace-antitrace map techniques avoids numerical instability and strongly reduces computational time. Experimental measurements of a prototype satisfying predetermined requirements fabricated after the sequence generated by ?:(a, b)?(bba, bbba) show excellent agreement.
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
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.
International Nuclear Information System (INIS)
A set of projection images is acquired during longitudinal tomography with an image intensifier TV system. Reconstruction of tomograms in each desired plane is achieved by shifting and summing up to the digitalized projection images. Digital multilayer and conventional film tomograms mainly of the respiratory tract and skeleton have been compared in 100 patients. Image quality is comparable with both methods. Disadvantage of digital tomography is lower spatial resolution (512x512 matrix size); advantages include lower radiation dose, shorter study time, and facilities of digital imaging. (orig.)
J. Szajnar; P. Wróbel; T. Wróbel
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 200–450 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 ...
Serially recurrent osteoid osteoma.
Sampath, Srihari C; Sampath, Srinath C; Rosenthal, Daniel I
2015-06-01
Osteoid osteoma is a relatively common, benign, painful tumor of bone. It is widely believed to run a course culminating in spontaneous regression. The tumor can usually be eliminated by excision or ablation, although it may recur locally. Although management has classically been surgical, thermocoagulation via percutaneously delivered radiofrequency energy has demonstrated excellent results, typically resulting in durable response following a single treatment. Here, we present an unusual case of serially recurrent pathologically proven pediatric osteoid osteoma, treated by radiofrequency ablation five times over the course of 11 years. Limitations of RF ablation of osteoid osteoma and possible factors predisposing to incomplete treatment or recurrence are discussed. PMID:25503857
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
International Nuclear Information System (INIS)
Utilizing self-consistent Hartree-Fock calculations, several aspects of multilayers and interfaces are explored: enhancement and reduction of the local magnetic moments, magnetic coupling at the interfaces, magnetic arrangements within each film and among non-neighboring films, global symmetry of the systems, frustration, orientation of the various moments with respect to an outside applied field, and magnetic-field induced transitions. Magnetoresistance of ferromagnetic-normal-metal multilayers is found by solving the Boltzmann equation. Results explain the giant negative magnetoresistance encountered in these systems when an initial antiparallel arrangement is changed into a parallel configuration by an external magnetic field. The calculation depends on (1) geometric parameters (thicknesses of layers), (2) intrinsic metal parameters (number of conduction electrons, magnetization, and effective masses in layers), (3) bulk sample properties (conductivity relaxation times), (4) interface scattering properties (diffuse scattering versus potential scattering at the interfaces, and (5) outer surface scattering properties (specular versus diffuse surface scattering). It is found that a large negative magnetoresistance requires considerable asymmetry in interface scattering for the two spin orientations. Features of the interfaces that may produce an asymmetrical spin-dependent scattering are studied: varying interfacial geometric random roughness with no lateral coherence, correlated (quasi-periodic) roughness, and varying chemical composition of the interfaces. The interplay between these aspects of the interfaces may enhance or suppress the magnetoresistance, depending on whether it increases or decreases the asymmetry in the spin-dependent scattering of the conduction electrons
Recurrent Retroperitoneal Cystic Lymphangioma
Ozdemir, Huseyin; Kocakoc, Ercan; Bozgeyik, Zulkif; Cobanoglu, Bengu
2005-01-01
Retroperitoneal cystic lymphangioma is a rare congenital malformation. The majority of lymphangiomas are present at birth and nearly all present before the age of two years. We report a case of giant cystic retroperitoneal lymphangioma in a patient who first presented with symptoms at the age of 7, underwent surgery, and who then suffered a recurrent mass 11 years later.
Risk for Recurrence in Depression
Burcusa, Stephanie L.; Iacono, William G.
2007-01-01
Depression is a highly recurrent disorder with significant personal and public health consequences. Prevention of recurrence would be extremely desirable, and thus researchers have begun to identify risk factors that are specific to recurrence, which may be different from risk factors for first-onset of depression. Methodological issues in this area of research are briefly reviewed (e.g., the various definitions of “recurrence” and “depression”), followed by a review of studies on specific ri...
Exploring recurrences in quasiperiodic systems
Zou, Yong
2007-01-01
In this work, some new results to exploit the recurrence properties of quasiperiodic dynamical systems are presented by means of a two dimensional visualization technique, Recurrence Plots(RPs). Quasiperiodicity is the simplest form of dynamics exhibiting nontrivial recurrences, which are common in many nonlinear systems. The concept of recurrence was introduced to study the restricted three body problem and it is very useful for the characterization of nonlinear systems. I have analyzed in ...
Diffusion Processes on Multilayer Networks
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.
Bahi, Jacques M.; Couchot, Jean-François; Guyeux, Christophe; Salomon, Michel
2012-03-01
Many research works deal with chaotic neural networks for various fields of application. Unfortunately, up to now, these networks are usually claimed to be chaotic without any mathematical proof. The purpose of this paper is to establish, based on a rigorous theoretical framework, an equivalence between chaotic iterations according to Devaney and a particular class of neural networks. On the one hand, we show how to build such a network, on the other hand, we provide a method to check if a neural network is a chaotic one. Finally, the ability of classical feedforward multilayer perceptrons to learn sets of data obtained from a dynamical system is regarded. Various boolean functions are iterated on finite states. Iterations of some of them are proven to be chaotic as it is defined by Devaney. In that context, important differences occur in the training process, establishing with various neural networks that chaotic behaviors are far more difficult to learn.
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 200–450 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.
International Nuclear Information System (INIS)
Digital multilayer tomography combines the principles of conventional tomography with digital techniques. The development of this method in addition to DSA and digital radiography is another step forward towards the achievement of digital radiology. Clinical application of the method for initial experience and results is done in the Institut fuer Klinische Strahlenkunde of the Johannes Gutenberg University in Mainz, and so far seventy patients have been examined with the new diagnostic tool, covering the following regions of interest: hilus/lungs (30 patients); skeleton (28 patients); middle part of the face (7 patients); kidneys (5 patients). In all cases, conventional tomograms have been available for comparison. Dose measurements for assessing the required dose and the dose to the patient have been made with a pelvic phantom. (orig./MG)
A Three-Threshold Learning Rule Approaches the Maximal Capacity of Recurrent Neural Networks.
Alemi, Alireza; Baldassi, Carlo; Brunel, Nicolas; Zecchina, Riccardo
2015-08-01
Understanding the theoretical foundations of how memories are encoded and retrieved in neural populations is a central challenge in neuroscience. A popular theoretical scenario for modeling memory function is the attractor neural network scenario, whose prototype is the Hopfield model. The model simplicity and the locality of the synaptic update rules come at the cost of a poor storage capacity, compared with the capacity achieved with perceptron learning algorithms. Here, by transforming the perceptron learning rule, we present an online learning rule for a recurrent neural network that achieves near-maximal storage capacity without an explicit supervisory error signal, relying only upon locally accessible information. The fully-connected network consists of excitatory binary neurons with plastic recurrent connections and non-plastic inhibitory feedback stabilizing the network dynamics; the memory patterns to be memorized are presented online as strong afferent currents, producing a bimodal distribution for the neuron synaptic inputs. Synapses corresponding to active inputs are modified as a function of the value of the local fields with respect to three thresholds. Above the highest threshold, and below the lowest threshold, no plasticity occurs. In between these two thresholds, potentiation/depression occurs when the local field is above/below an intermediate threshold. We simulated and analyzed a network of binary neurons implementing this rule and measured its storage capacity for different sizes of the basins of attraction. The storage capacity obtained through numerical simulations is shown to be close to the value predicted by analytical calculations. We also measured the dependence of capacity on the strength of external inputs. Finally, we quantified the statistics of the resulting synaptic connectivity matrix, and found that both the fraction of zero weight synapses and the degree of symmetry of the weight matrix increase with the number of stored patterns. PMID:26291608
A Three-Threshold Learning Rule Approaches the Maximal Capacity of Recurrent Neural Networks
Alemi, Alireza; Baldassi, Carlo; Brunel, Nicolas; Zecchina, Riccardo
2015-01-01
Understanding the theoretical foundations of how memories are encoded and retrieved in neural populations is a central challenge in neuroscience. A popular theoretical scenario for modeling memory function is the attractor neural network scenario, whose prototype is the Hopfield model. The model simplicity and the locality of the synaptic update rules come at the cost of a poor storage capacity, compared with the capacity achieved with perceptron learning algorithms. Here, by transforming the perceptron learning rule, we present an online learning rule for a recurrent neural network that achieves near-maximal storage capacity without an explicit supervisory error signal, relying only upon locally accessible information. The fully-connected network consists of excitatory binary neurons with plastic recurrent connections and non-plastic inhibitory feedback stabilizing the network dynamics; the memory patterns to be memorized are presented online as strong afferent currents, producing a bimodal distribution for the neuron synaptic inputs. Synapses corresponding to active inputs are modified as a function of the value of the local fields with respect to three thresholds. Above the highest threshold, and below the lowest threshold, no plasticity occurs. In between these two thresholds, potentiation/depression occurs when the local field is above/below an intermediate threshold. We simulated and analyzed a network of binary neurons implementing this rule and measured its storage capacity for different sizes of the basins of attraction. The storage capacity obtained through numerical simulations is shown to be close to the value predicted by analytical calculations. We also measured the dependence of capacity on the strength of external inputs. Finally, we quantified the statistics of the resulting synaptic connectivity matrix, and found that both the fraction of zero weight synapses and the degree of symmetry of the weight matrix increase with the number of stored patterns. PMID:26291608
A morphological perceptron with gradient-based learning for Brazilian stock market forecasting.
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
Controlling light with plasmonic multilayers
DEFF Research Database (Denmark)
Orlov, Alexey A.; Zhukovsky, Sergei
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 A number of fundamental electromagnetic effects unique to the latter are identified and demonstrated. Examples include the evolution of isofrequency contour shape from elliptical to hyperbolic, all-angle negative refraction, and nonlocality-induced optical birefringence. Analysis of the underlying physical causes, which are spatial dispersion and optical nonlocality, is also reviewed. These recent results are extremely promising for a number of applications ranging from nanolithography to optical cloaking. © 2014 Elsevier B.V.
Paediatric recurrent herpetic whitlow.
Patel, Ramnik; Kumar, Hemant; More, Bharat; Patricolo, Mario
2013-01-01
We present a case of recurrent painful blisters of middle phalanx of the left ring finger of a 15-month-old previously healthy and immunocompetent female child. These lesions initially were confused with infective bacterial whitlow, treated with incision and drainage, and later with cigarette burns which led to referral to child protection team. Paediatric dermatologist finally diagnosed after scrapping and virology culture. The patient had recovery following full treatment with topical and systemic acyclovir. She presented again at the age of 4 with recurrence which required topical and systemic acyclovir therapy with good recovery. It is important to be aware of the danger of incorrect diagnosis, raising child protection concerns and management leading to danger of cross infection and serious illness especially in the immunocompromised patients. PMID:23904423
Paediatric recurrent herpetic whitlow
Patel, Ramnik; Kumar, Hemant; More, Bharat; Patricolo, Mario
2013-01-01
We present a case of recurrent painful blisters of middle phalanx of the left ring finger of a 15-month-old previously healthy and immunocompetent female child. These lesions initially were confused with infective bacterial whitlow, treated with incision and drainage, and later with cigarette burns which led to referral to child protection team. Paediatric dermatologist finally diagnosed after scrapping and virology culture. The patient had recovery following full treatment with topical and systemic acyclovir. She presented again at the age of 4 with recurrence which required topical and systemic acyclovir therapy with good recovery. It is important to be aware of the danger of incorrect diagnosis, raising child protection concerns and management leading to danger of cross infection and serious illness especially in the immunocompromised patients. PMID:23904423
Recurrent amiodarone pulmonary toxicity.
Chendrasekhar, A; Barke, R A; Druck, P
1996-01-01
Amiodarone, a widely used antiarrhythmic drug, is associated with pulmonary toxicity, with an estimated mortality of 1% to 33%. Standard treatment for amiodarone pulmonary toxicity (APT) has been discontinuance of the drug and steroid therapy. We report a case of APT that recurred after withdrawal of steroids and failed to respond to reinstatement of steroid therapy. Recurrent APT is a rare clinical entity that has been reported only twice in recent literature. PMID:8545700
Recurrent respiratory papillomatosis
Tasca, R A; Clarke, R W
2006-01-01
Recurrent respiratory papillomatosis (RRP) is a benign, often multi?focal neoplasm.1 A potentially fatal manifestation of human papilloma virus infection, the condition is characterised by multiple warty excrescences on the mucosal surface of the respiratory tract. RRP is rare—incidence is estimated at 3.5 per million person?years,2 with a prevalence of 4 in 100?000 children. Affected children usually require multiple interventions; the impact on patients, their families, and the healthcare s...
Karlsson, Amy J.; Flessner, Ryan M.; Gellman1, Samuel H.; Lynn, David M.; Palecek, Sean P.
2010-01-01
The fungal pathogen Candida albicans can form biofilms on the surfaces of medical devices that are resistant to drug treatment and provide a reservoir for recurrent infections. The use of fungicidal or fungistatic materials to fabricate or coat the surfaces of medical devices has the potential to reduce or eliminate the incidence of biofilm-associated infections. Here, we report on (i) the fabrication of multilayered polyelectrolyte thin films (PEMs) that promote the surface-mediated release ...
Incarcerated recurrent Amyand's hernia
Quartey, Benjamin; Ugochukwu, Obinna; Kuehn, Reed; Ospina, Karen
2012-01-01
Amyand's hernia is a rarity and a recurrent case is extremely rare. A 71-year-old male with a previous history of right inguinal hernia repair presented to the emergency department with a 1-day history of pain in the right groin. A physical examination revealed a nonreducible right inguinal hernia. A computed tomography scan showed a 1.3-cm appendix with surrounding inflammation within a right inguinal hernia. An emergent right groin exploration revealed an incarcerated and injected non-perfo...
Endoscopic Cubital Tunnel Recurrence Rates
Cobb, Tyson K.; Sterbank, Patrick T.; Lemke, Jon H.
2009-01-01
Cubital tunnel syndrome is the second most common nerve entrapment in the upper extremity. There are no current publications concerning the recurrence rates after endoscopic cubital tunnel release. The purpose of this study is to evaluate the recurrence rate of endoscopic cubital tunnel release compared to published reports of recurrence following open cubital tunnel procedures. We reviewed 134 consecutive cases of endoscopic cubital tunnel release in 117 patients. There were 104 cases in 94 ...
Recurrence theorems: A unified account
International Nuclear Information System (INIS)
I discuss classical and quantum recurrence theorems in a unified manner, treating both as generalisations of the fact that a system with a finite state space only has so many places to go. Along the way, I prove versions of the recurrence theorem applicable to dynamics on linear and metric spaces and make some comments about applications of the classical recurrence theorem in the foundations of statistical mechanics
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.
Poincaré recurrence:. old and new
Barreira, Luis
2006-03-01
The classical theorem of Poincaré on recurrence only gives information of qualitative nature. On the other hand it is clearly a matter of intrinsic difficulty and not of lack of interest that less is known concerning the quantitative behavior of recurrence. Here we discuss recent developments that include the almost everywhere coincidence between the recurrence rate and the pointwise dimension in the case of hyperbolic dynamics. We also discuss the almost product structure of recurrence, which closely imitates the product structure provided by the families of stable and unstable manifolds as well as the almost product structure of hyperbolic measures.
Epidemiology of recurrent venous thrombosis
Scientific Electronic Library Online (English)
D.D., Ribeiro; W.M., Lijfering; S.M., Barreto; F.R., Rosendaal; S.M., Rezende.
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.
Directory of Open Access Journals (Sweden)
V G Mahima
2011-01-01
Full Text Available Angioleiomyomas are vascular variant of leiomyomas which are benign tumors of smooth muscle. They are exceedingly rare in the oral cavity. Malignant transformation of these tumors has also been reported occasionally which warrants knowledge of this soft tissue tumor. A 57 year old male patient reported with a 15 day history of an asymptomatic growth that had started insidiously in his lower left back tooth region. Clinical examination revealed a solitary, oval, sessile growth in the mandibular left retro molar region. Excisional biopsy was suggestive of Angioleiomyoma. A recurrence of the same was noted two months later which was also histopathologically reported as Angioleiomyoma. The same was confirmed using special stains. This case reports an unusual presentation of Angioleiomyoma with regards to both recurrence as well as rapid growth. It is important to be well aware of this uncommon entity as these tumors often can mimic or transform into malignancy. Precise clinicopathological examinations are therefore invaluable in establishing an accurate diagnosis and delivering suitable treatment.
Recovery in Multilayer Optical Networks
Pickavet, Mario; Demeester, Piet; Colle, Didier; Staessens, Dimitri; Puype, Bart; Depré, Leen; Lievens, Ilse
2006-01-01
The integration of different network technologies into a multilayer network, as in Internet-based networks carried by optical transport networks (OTNs), creates new opportunities but also challenges with respect to network survivability. In different network layers, recovery mechanisms that are active can be exploited jointly to reach a more efficient or faster recovery from failures. This interworking is also indispensable in order to overcome the variety of failure scenarios that can occur in the multilayer-network environment. A well-considered coordination between the different layers and their recovery mechanisms is crucial in order to attain high performance recovery. This paper provides an overview of multilayer recovery issues and solutions in an Internet protocol (IP)-over-optical-network environment, which is illustrated by quantitative case studies.
Structural reducibility of multilayer networks
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%.
Stress analysis in multilayer structures
White, Dongming Yuan
1997-12-01
The magnitude and distribution of thermal stresses in multilayer thin film structures have been modeled using a analytical solution method (ASM) and a newly developed hybrid finite element method (HFEM). This combined approach treats stress singularity as well as nonsingularity with equal ease. The use of hybrid elements based on an analytical solution of the stress singularity at the free edge has been found to provide accurate thermal stress solutions with fast convergence. Modeling of stress behavior in multilayer structures has been extended to include solutions for non-90sp° wedges (so called sharp edges) and solutions for multimaterial wedges. The dependence of the order of the stress singularity as well as the intensity of the stress singularity on the specific free edge geometry has been worked out as well. The results of theoretical analysis and calculations have made feasible the development of a software program, titled "Multilayer Structures" (MLS). The program is Windows-based. It is user friendly, allowing efficient and rapid thermal stress analysis of virtually any multilayer structure. It is seen as a valuable tool in design and for manufacturing and quality control functions in areas in which multilayer structures play a vital role. With a specially designed automesh engine and a simplified procedure for residual stress calculations, tedious preprocessing procedures need not be of concern. The program still provides the opportunity to use conventional finite element analysis. The MLS program has been applied and evaluated in various areas, such as in the optimization of substrate and film thicknesses in Multi Chip Modules (MCM's), the design of functionally gradient transition layers required in the bonding of dissimilar materials, and the identification of suitable substrates or buffer layers in diamond film deposition. The work reported in this dissertation constitutes a first step towards a full understanding of the mechanical behavior of multilayer structures and the development of a complete and comprehensive tool to predict performance.
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.
Computing and fabricating multilayer models
Holroyd, Michael; Baran, Ilya; Lawrence, Jason; Matusik, Wojciech
2011-01-01
We present a method for automatically converting a digital 3D model into a multilayer model: a parallel stack of high-resolution 2D images embedded within a semi-transparent medium. Multilayer models can be produced quickly and cheaply and provide a strong sense of an object's 3D shape and texture over a wide range of viewing directions. Our method is designed to minimize visible cracks and other artifacts that can arise when projecting an input model onto a small number of parallel planes, a...
Treatment of juvenile recurrent parotitis.
Katz, Philippe; Hartl, Dana M; Guerre, Agnès
2009-12-01
Juvenile recurrent parotitis (JRP) can be a debilitating illness in children. Knowing how to recognize and diagnose it for early treatment avoids recurrences that could lead to significant destruction of the glandular parenchyma. This article discusses the various therapeutic modalities proposed in the literature (medical treatment or sialendoscopy) and describes the authors' treatment of choice of combining antibiotics and iodinated oil sialography. PMID:19962009
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).
Multilayer Controller for Outdoor Vehicle
DEFF Research Database (Denmark)
Reske-Nielsen, Anders; Mejnertsen, AsbjØrn
2006-01-01
A full software and hardware solution has been designed, implemented and tested for control of a small agricultural automatic tractor. The objective was to realise a user-friendly, multi-layer controller architecture for an outdoor platform. The collaborative research work was done as a part of a research project within the field of automated agriculture and precision farming.
Stability of multilayered neural networks
International Nuclear Information System (INIS)
Stability of multilayered neural networks against synaptic changes has been studied numerically. The average maximum change goes to zero as the number N of input neurons is much greater than one. If a fixed fraction of output errors is allowed, then the synapses may be changed within some limits even for large N. (Author)
Nonparametric Estimation of a Recurrent Survival Function
WANG, MEI-CHENG; Chang, Shu-Hui
1999-01-01
Recurrent event data are frequently encountered in studies with longitudinal designs. Let the recurrence time be the time between two successive recurrent events. Recurrence times can be treated as a type of correlated survival data in statistical analysis. In general, because of the ordinal nature of recurrence times, statistical methods that are appropriate for standard correlated survival data in marginal models may not be applicable to recurrence time data. Specifically, for estimating th...
Shafter, A W; Rector, T A; Schweizer, F; Hornoch, K; Orio, M; Pietsch, W; Darnley, M J; Williams, S C; Bode, M F; Bryan, J
2014-01-01
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 candidates. To pass the initial screen and qualify as a recurrent nova 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 recurrent nova 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 recurrent novae, with another 8 systems (17 eruptions) deemed unlikely to be recurrent. Of the remaining 16 systems, 12 candidates (32 eruptions) were judged to be recurrent novae, with an additional 4 systems (8 eruptions) b...
$\\omega$-recurrence in cocycles
Chaika, Jon
2011-01-01
After relating the notion of $\\omega$-recurrence in skew products to the range of values taken by partial ergodic sums and Lyapunov exponents, ergodic $\\mathbb{Z}$-valued cocycles over an irrational rotation are presented in detail. First, the generic situation is studied and shown to be $1/n$-recurrent. It is then shown that for any $\\omega(n) 1/2$, there are uncountably many infinite staircases (a certain specific cocycle over a rotation) which are \\textit{not} $\\omega$-recurrent, and therefore have positive Lyapunov exponent. A further section makes brief remarks regarding cocycles over interval exchange transformations of periodic type.
Recurrent respiratory papillomatosis. Case report.
Cong Luong, Tai; Scrigni, Adriana; Ruvinsky, Silvina; Cocciaglia, Alejandro; Rowensztein, Hernán
2015-08-01
Recurrent respiratory papillomatosis (RRP) is a rare condition characterized by recurrent growth of papilloma in the respiratory tract. RRP is caused by human papilloma virus. Its incidence is 4 per 100 000 children. Vertical transmission of the virus during gestation or during delivery is the major route of contracting the disease in children. One hundred and thirty different human papilloma virus types have been identified. Types 6 and 11 are involved in RRP and type 11 develops more aggressive disease with recurrence and progression to the respiratory tract and also nasopharyngeal surface. We present a 7 year old boy with diagnosis of RRP based on radiology and endoscopy. PMID:26172017
STDP in recurrent neuronal networks
Directory of Open Access Journals (Sweden)
MatthieuGilson
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.
Giant recurrent retroperitoneal liposarcoma presenting as a recurrent inguinal hernia
Sameer Vora; Kori, Channabasappa G.; Shenoy, Sachin S.; Borisa, Ashok D; Girish D. Bakhshi; Bhandarwar, Ajay H.
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...
Chronic recurrent multifocal osteomyelitis.
Roderick, Marion R; Ramanan, Athimalaipet V
2013-01-01
Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disease occurring primarily in children and adolescents. Episodes of systemic inflammation occur due to immune dysregulation without autoantibodies, pathogens or antigen-specific T cells. CRMO is characterised by the insidious onset of pain with swelling and tenderness over the affected bones. Clavicular involvement was the classical description; however, the metaphyses and epiphyses of long bones are frequently affected. Lesions may occur in any bone, including vertebrae. Characteristic imaging includes bone oedema, lytic areas, periosteal reaction and soft tissue reaction. Biopsies from affected areas display polymorphonuclear leucocytes with osteoclasts and necrosis in the early stages. Subsequently, lymphocytes and plasma cells predominate followed by fibrosis and signs of reactive new bone forming around the inflammation. Diagnosis is facilitated by the use of STIR MRI scanning, potentially obviating the need for biopsy and unnecessary long-term antibiotics due to incorrect diagnosis. Treatment options include non-steroidal anti-inflammatory drugs and bisphosphonates. Biologics have been tried in resistant cases with promising initial results. Gene identification has not proved easy although research in this area continues. Early descriptions of the disease suggested a benign course; however, longer-term follow up shows that it can cause significant morbidity and longer-term disability. Although it has always been thought of as very rare, the prevalence is likely to be vastly underestimated due to poor recognition of the disease. PMID:23654059
Coping with Fear of Recurrence
... a Job After Cancer Stopping Work After Cancer Treatment Post-Traumatic Stress Disorder and Cancer Post-Traumatic Growth and Cancer Long-Term Side Effects of Cancer Treatment Dealing With Cancer Recurrence Making a Difference Survivor ...
Recurrent ameloblastoma of the mandible
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).
Primary breast lymphoma; disease recurrence
Directory of Open Access Journals (Sweden)
Hüseyin KADIO?LU
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.
Recurrence risks in mental retardation.
Crow, Y. J.; Tolmie, J.L.
1998-01-01
Despite improvements in diagnostic techniques and progress made in mapping genes associated with syndromal mental handicap, the estimation of recurrence risks in non-syndromal mental retardation is still dependent on empirical data. Unfortunately, few studies are available to guide the clinician and their results differ significantly. For example, recurrence risks to all sibs of a male index patient with severe mental retardation vary between 3.5% and 14% in commonly quoted series. The presen...
Recurrence for random dynamical systems
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.
Multilayer weighted social network model
Murase, Yohsuke; Török, János; Jo, Hang-Hyun; Kaski, Kimmo; Kertész, János
2014-11-01
Recent empirical studies using large-scale data sets have validated the Granovetter hypothesis on the structure of the society in that there are strongly wired communities connected by weak ties. However, as interaction between individuals takes place in diverse contexts, these communities turn out to be overlapping. This implies that the society has a multilayered structure, where the layers represent the different contexts. To model this structure we begin with a single-layer weighted social network (WSN) model showing the Granovetterian structure. We find that when merging such WSN models, a sufficient amount of interlayer correlation is needed to maintain the relationship between topology and link weights, while these correlations destroy the enhancement in the community overlap due to multiple layers. To resolve this, we devise a geographic multilayer WSN model, where the indirect interlayer correlations due to the geographic constraints of individuals enhance the overlaps between the communities and, at the same time, the Granovetterian structure is preserved.
Anomalous magnetoresistance in Fibonacci multilayers.
Energy Technology Data Exchange (ETDEWEB)
Machado, L. D.; Bezerra, C. G.; Correa, M. A.; Chesman, C.; Pearson, J. E.; Hoffmann, A. (Materials Science Division); (Universidade Federal do Rio Grande do Norte)
2012-01-01
We theoretically investigated magnetoresistance curves in quasiperiodic magnetic multilayers for two different growth directions, namely, [110] and [100]. We considered identical ferromagnetic layers separated by nonmagnetic 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 coupling, and biquadratic coupling. The minimum energy was determined by the gradient method and the equilibrium magnetization directions found were used to calculate magnetoresistance curves. By choosing spacers with a thickness such that biquadratic coupling is stronger than bilinear coupling, unusual behaviors for the magnetoresistance were observed: (i) for the [110] case, there is a different behavior for structures based on even and odd Fibonacci generations, and, more interesting, (ii) for the [100] case, we found magnetic field ranges for which the magnetoresistance increases with magnetic field.
Polyelectrolyte Multilayers in Tissue Engineering
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...
Constructing multilayers with absorbing materials
Larruquert, Juan Ignacio; Vidal-Dasilva, M.; García-Cortés, S.; Fernández Perea, Mónica; Méndez, José A.; Aznárez, José 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...
Shock multiplication in multilayered targets
International Nuclear Information System (INIS)
The behavior of laser-driven shock waves in impedance-match, multilayered targets has been explored in hydrodynamic simulations as well as experimental measurements, taking aluminum-gold as the sample target. To achieve maximum pressure enhancement in the gold layer, one needs to consider not only the aluminum layer thickness but also the thickness of the gold layer. Such optimization was demonstrated in the numerical calculations which showed good agreement with observations. 13 references
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
Multilayer Analysis and Visualization of Networks
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.
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
Polarizability and Screening in Chiral Multilayer Graphene
Min, Hongki; Hwang, E. H.; Sarma, S. Das
2012-01-01
We calculate the static polarizability of multilayer graphene and study the effect of stacking arrangement, carrier density, and onsite energy difference on graphene screening properties. At low densities, the energy spectrum of multilayer graphene is described by a set of chiral two-dimensional electron systems and the associated chiral nature determines the screening properties of multilayer graphene showing very different behavior depending on whether the chirality index ...
Mathematical Formulation of Multilayer Networks
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.
Magnetoresistive multilayers deposited on the AAO membranes
International Nuclear Information System (INIS)
Silicon and GaAs wafers are the most commonly used substrates for deposition of giant magnetoresistive (GMR) multilayers. We explored a new type of a substrate, prepared electrochemically by anodization of aluminum sheets, for deposition of GMR multilayers. The surface of this AAO substrate consists of nanosized hemispheres organized in a regular hexagonal array. The current applied along the substrate surface intersects many magnetic layers in the multilayered structure, which results in enhancement of giant magnetoresistance effect. The GMR effect in uncoupled Co/Cu multilayers was significantly larger than the magnetoresistance of similar structures deposited on Si
On uniform recurrence of a direct product
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.
Shafter, A. W.; Henze, M.; Rector, T. A.; Schweizer, F.; Hornoch, K.; Orio, M.; Pietsch, W.; Darnley, M. J.; Williams, S. C.; Bode, M. F.; Bryan, J.
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.
International Nuclear Information System (INIS)
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
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 Ond?ejov (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.
Multi-Layer E-Textile Circuits
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.
Multilayer Graphene for Waveguide Terahertz Modulator
DEFF Research Database (Denmark)
Khromova, I.; Andryieuski, 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.
Phase stability in metallic multilayers
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 (spherical 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 (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.
Electronic Properties of Graphene Multilayers
Sadeghi, Hamed; de Rojas, Julius; Bill, Andreas
2012-11-01
We determine numerically the tight-binding band structure, the density of states and the plasmon spectrum of N stacked graphene layers beyond the Dirac cone approximation. We calculate the polarizability in the random phase approximation and determine the dielectric function ?(q,?). This allows to determine the acoustic and optical modes of the plasmon spectrum. Because we do not limit ourselves to the Dirac cone approximation we cannot use the semi-analytic approach usually proposed for graphene in the literature. Instead we use a combination of numerical procedures to determine the collective modes of graphene multilayer.
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)
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)
Recurrence Formulas for Fibonacci Sums
Brandao, Adilson J. V.; Martins, Joao L.
2008-01-01
In this article we present a new recurrence formula for a finite sum involving the Fibonacci sequence. Furthermore, we state an algorithm to compute the sum of a power series related to Fibonacci series, without the use of term-by-term differentiation theorem
Orthogonalization process by recurrence relations
International Nuclear Information System (INIS)
An orthogonalization process is proposed, applicable to spaces which are realizations of abstract Hilbert space. It is simpler than the Gram-Schmidt process. A recurrence relation which orthogonalizes a physical space is proposed and it is shown that the generalized Langevin equation is contained therein. This process serves as a basis for understanding the nature of the dynamic many-body formalism
Recent advances in etched multilayer X-ray optics
André, J.; Sammar, A.; Bac, S.; Ouahabi, M.; Idir, M.; 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.?
Fifth International Symposium on Recurrence Plot
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...
14 CFR 121.427 - Recurrent training.
2010-01-01
...respectively. (4) Approved recurrent CRM training. For flight crewmembers, this...training (LOFT) session. The recurrent CRM training requirement does not apply until a person has completed the applicable initial CRM training required by §§ 121.419,...
Giant recurrent retroperitoneal liposarcoma presenting as a recurrent inguinal hernia
Directory of Open Access Journals (Sweden)
Sameer Vora
2011-09-01
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.
On generalized M-projectively recurrent manifolds
Directory of Open Access Journals (Sweden)
Uday Chand De
2014-04-01
Full Text Available The purpose of the present paper is to study generalized M-projectively recurrent manifolds. Some geometric properties of generalized M-projectively recurrent manifolds have been studied under certain curvature conditions. An application of such a manifold in the theory of relativity has also been shown. Finally, we give an example of a generalized M-projectively recurrent manifold.
Recurrent Idiopathic Facial Paralysis: A Case Report
Directory of Open Access Journals (Sweden)
Hale Hekim Balo?lu
2010-09-01
Full Text Available Idiopathic facial paralysis is the mononeuropathy Multiple recurrences of idiopathic facial paralysis in a patient may be the sign or sympton of a serious illness. therefore; in recurrent cases, family history, systemic diseases and malignancy must be investigated. In this report, a case of recurrent idiopathic facial paralysis is presented.
2015-06-02
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
Recurrent and non-recurrent trajectories in a chaotic system
Directory of Open Access Journals (Sweden)
A. O. Akala
2010-09-01
Full Text Available The dynamics of a system subjected to a potential equal to the sum of the Henon-Heiles potential and that of thehydrogen atom in a uniform magnetic field has been studied. Depending on the energy of the system, the Poincaresurface is characterised by regions of regular motion, appearing and disappearing regions of regular motion, regions ofrecurrent (regular and chaotic trajectories and those of non-recurrent trajectories.
Tunable optical properties of multilayers black phosphorus
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.
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 ?m 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-?m 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
Multilayer networks: metrics and spectral properties
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.
Conductance through multilayer graphene films.
Kuroda, Marcelo A; Tersoff, J; Newns, Dennis M; Martyna, Glenn J
2011-09-14
The ballistic conductance through junctions between multilayer graphene films and several different metals is studied using ab initio calculations within the local density approximation. The system consists of films of up to four graphene layers (Bernal stacking) between metallic electrodes, assuming reasonable metal-graphene epitaxial relationships. For some metals, the conductance decays exponentially with increasing number of layers, while for others the conductance saturates with film thickness. This difference in asymptotic behavior stems from the crystal momentum (mis)match between the bulk Fermi-level states in the electrode and those in the film. In contrast, for sufficiently thin films the bonding between the metal and the adjacent graphene layer dominates, giving a metal dependence for graphene similar to that seen experimentally for single-wall carbon nanotubes. Among the metals considered here, we find Pd to be the best for electrodes to films with up to 4 graphene layers. PMID:21834553
Centrality in Interconnected Multilayer Networks
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...
Robustness of multilayer oscillator networks
Morino, Kai; Tanaka, Gouhei; Aihara, Kazuyuki
2011-05-01
We consider the robustness of multilayer networks composed of active and inactive oscillators from the viewpoint of interlayer coupling effects through the aging transition [H. Daido and K. Nakanishi, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.93.104101 93, 104101 (2004)]. We show in detail that two-layer networks increase or decrease their robustness depending on interlayer coupling schemes compared with single-layer networks. In addition, we find that an increase of mismatches of oscillator types (active or inactive) among interlayer-connected oscillators reduces the robustness of the networks with mean-field, chain, and diffusive interlayer couplings in two-layer networks. Moreover, we discuss the robustness of networks with more than two layers.
Magnetic quantization in multilayer graphenes
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...
Recurrent gossypiboma in the thigh
International Nuclear Information System (INIS)
Gossypiboma, an iatrogenic mass lesion caused by a retained surgical sponge is an extremely rare event following musculoskeletal procedures. This entity is therefore a very unusual experience and can create considerable confusion. Unsuspecting surgeons may thus be caught out by this unlikely presentation. We present our experience with a recurrent gossypiboma in the thigh occurring several years after surgical evacuation of a similar gossypiboma from the same anatomic location with interval resolution of symptoms. The purpose of this case report is to highlight the possibility of a ''recurrent'' soft tissue mass occurring for reasons other than a neoplasm. In the absence of a definitive biopsy diagnosis of tumor in patients who have undergone prior surgical procedures in that area, it may be more prudent to adopt a conservative surgical resection rather than a conventional radical resection as warranted by the dramatic clinical presentation mimicking a soft tissue sarcoma. (orig.)
Recurrent gossypiboma in the thigh
Energy Technology Data Exchange (ETDEWEB)
Puri, Ajay; Anchan, Chetan; Agarwal, Manish G. [Tata Memorial Hospital, Department of Orthopaedic Oncology, Mumbai (India); Jambhekar, Nirmala A. [Tata Memorial Hospital, Department of Pathology, Mumbai (India); Badwe, Rajendra A. [Tata Memorial Hospital, Department of Surgical Oncology, Mumbai (India)
2007-06-15
Gossypiboma, an iatrogenic mass lesion caused by a retained surgical sponge is an extremely rare event following musculoskeletal procedures. This entity is therefore a very unusual experience and can create considerable confusion. Unsuspecting surgeons may thus be caught out by this unlikely presentation. We present our experience with a recurrent gossypiboma in the thigh occurring several years after surgical evacuation of a similar gossypiboma from the same anatomic location with interval resolution of symptoms. The purpose of this case report is to highlight the possibility of a ''recurrent'' soft tissue mass occurring for reasons other than a neoplasm. In the absence of a definitive biopsy diagnosis of tumor in patients who have undergone prior surgical procedures in that area, it may be more prudent to adopt a conservative surgical resection rather than a conventional radical resection as warranted by the dramatic clinical presentation mimicking a soft tissue sarcoma. (orig.)
[Recurrent erysipelas and cellulitis: management].
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
Visualizing and Understanding Recurrent Networks
Karpathy, Andrej; Johnson, Justin; Li, Fei-Fei
2015-01-01
Recurrent Neural Networks (RNNs), and specifically a variant with Long Short-Term Memory (LSTM), are enjoying renewed interest as a result of successful applications in a wide range of machine learning problems that involve sequential data. However, while LSTMs provide exceptional results in practice, the source of their performance and their limitations remain rather poorly understood. Using character-level language models as an interpretable testbed, we aim to bridge this ...
Recurrence In Turbulent Dynamical Systems.
Czech Academy of Sciences Publication Activity Database
Uruba, Václav
Prague : Institute of Thermomechanics AS CR, v. v. i., 2011 - (P?íhoda, J.; Kozel, K.), s. 129-132 ISBN 978-80-87012-32-1. [Topical Problems of Fluid Mechanics 2011. Praha (CZ), 16.02.2011-17.02.2011] R&D Projects: GA ?R GA101/08/1112; GA ?R GAP101/10/1230 Institutional research plan: CEZ:AV0Z20760514 Keywords : turbulence * recurrence * dynamical systems Subject RIV: BK - Fluid Dynamics
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
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
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 an ethylene-vinyl acetate copolymer, a core layer of a barrier film comprising vinylidene chloride-methyl acrylate copolymer, and a second outer layer of an 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 multilayer film is irradiated to a dosage level of between 1 megarad and 5 megarads and heat-sealed in the form of a bag. The bag has improved storage stability characteristics
MRI in recurrent nasopharyngeal carcinoma
International Nuclear Information System (INIS)
In this study, we retrospectively reviewed the MRI features of recurrent nasopharyngeal carcinoma (NPC) in 72 patients who underwent MRI before and after gadolinium injection. Recurrent NPC exhibited a high degree of regional spread and a variety of signal intensities and contours. MRI showed a nasopharyngeal mass in 50 patients (69.4 %); other sites of involvement included the parapharyngeal space (44.4 %), nasal cavity (12.5 %), paranasal sinuses (27.8 %), oropharynx (4.2 %), orbit (8.3 %), infratemporal fossa (18.1 %), skull base (59.8 %), intracranial area (51.4 %) and regional lymph nodes (15.3 %). On T2-weighted images, the nasopharyngeal mass gave high signal in 9 of 50 cases (18 %), intermediate in 27 (54 %), mixed in 8 (16 %) and low signal in 6 (12 %). Contrast enhancement was strong in 12 cases (24 %), moderate in 29 (58 %) and heterogeneous in 9 (18 %). The lesion was convex in 31 cases (62 %) and concave or straight in 19 (38 %). Recognition of the distribution and the appearance of recurrent NPC on MRI is essential for timely diagnosis and appropriate treatment. (orig.)
Fretting wear of metallic multilayer films
International Nuclear Information System (INIS)
Fretting wear behaviour of electrodeposited Cu/Ni multilayer films with 10 and 5 nm thick sublayers has been investigated against a hardened steel ball as the counter body and compared with that of the constituents, Cu and Ni. The wear tests were carried out by using a ball-on-flat geometry at a translation frequency of 8 Hz and slip amplitude of 100 ?m. Friction force was recorded on line during the tests. At the end of the tests, the wear scars were examined by laser surface profilometry, scanning electron microscopy and energy dispersive X-ray microanalysis. It has been observed that the frictional and wear mechanisms are very different for copper, nickel and Cu/Ni multilayers. Fretting of copper creates a relatively smooth wear scar mainly by mechanical ploughing of the asperities on steel counterbody (abrasive wear) and shows a very little third body interaction. Fretting of nickel involves adhesive wear resulting in a large transfer of steel to nickel, which is attributed to the strong chemical interaction between nickel and the steel counterbody. Fretting on multilayers involves a strong third body interaction resulting in ploughing mainly by debris (abrasive wear). The coefficient of friction is approximately 0.45 for copper, and approximately 0.8 for nickel as well as for multilayers. The values of the coefficient of friction for nickel and Cu/Ni multilayers found under the present fretting conditions are approximately double the corresponding values reported earlier for sliding wear conditions. It has been found that Cu/Ni multilayer is more resistance to fretting wear than the constituents, copper and nickel. Furthermore, the fretting wear resistance of Cu/Ni multilayers with 5 nm thick sublayer is better than that of the multilayers with 10 nm thick sublayers
Interlayer coupling in rotationally faulted multilayer graphenes
Mele, E. J.
2011-01-01
This article reviews progress in the theoretical modelling of the electronic structure of rotationally faulted multilayer graphenes. In these systems the crystallographic axes of neighboring layers are misaligned so that the layer stacking does not occur in the Bernal structure observed in three dimensional graphite and frequently found in exfoliated bilayer graphene. Notably, rotationally faulted graphenes are commonly found in other forms of multilayer graphene including e...
Multilayer Nanofilms as Substrates for Hepatocellular Applications
Wittmer, Corinne R.; Phelps, Jennifer A.; Lepus, Christin M.; Saltzman, W. Mark; Harding, Martha J.; Paul R. Van Tassel
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...
2015-02-19
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
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.
Recurrent priapism from therapeutic quetiapine.
Saghafi, Omeed; Kao, Amanda; Druck, Jeffrey
2014-02-01
Priapism is rarely related to use of non-erectile related medications. The objective was to educate about the multiple possible causes of priapism and to provide treatment recommendations for the different types of priapism. We present the case of a 43-year-old African American male with a history of schizoaffective disorder who presented to our emergency department multiple times over a three year period with priapism, each episode related to the ingestion of quetiapine. Following penile aspiration and intercavernosal injection of phenylephrine, this patient had resolution of his priapism. This case demonstrates an unusual case of recurrent priapism. PMID:24578777
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
Multilayer contactless dielectrophoresis: theoretical considerations.
Sano, Michael B; Salmanzadeh, Alireza; Davalos, Rafael V
2012-07-01
Dielectrophoresis (DEP), the movement of dielectric particles in a nonuniform electric field, is of particular interest due to its ability to manipulate particles based on their unique electrical properties. Contactless DEP (cDEP) is an extension of traditional and insulator-based DEP topologies. The devices consist of a sample channel and fluid electrode channels filled with a highly conductive media. A thin insulating membrane between the sample channel and the fluid electrode channels serves to isolate the sample from direct contact with metal electrodes. Here we investigate, for the first time, the properties of multilayer devices in which the sample and electrode channels occupy distinct layers. Simulations are conducted using commercially available finite element software and a less computationally demanding numerical approximation is presented and validated. We show that devices can be created that achieve a similar level of electrical performance to other cDEP devices presented in the literature while increasing fluid throughput. We conclude, based on these models, that the ultimate limiting factors in device performance resides in breakdown voltage of the barrier material and the ability to generate high-voltage, high-frequency signals. Finally, we demonstrate trapping of MDA-MB-231 breast cancer cells in a prototype device at a flow rate of 1.0 mL/h when 250 V(RMS) at 600 kHz is applied. PMID:22806458
Cates, Justin M M
2015-09-01
The optimal management of recurrent desmoid-type fibromatosis is undefined. This study was performed to determine what factors, if any, predict second recurrence after surgical resection of recurrent desmoid tumors. Of 41 patients with recurrent desmoid-type fibromatosis, 29 underwent surgical resection and 8 were followed by observation. Four others received adjuvant chemo/pharmacotherapy. Clinicopathologic features were assessed as prognostic factors for second recurrence after surgical resection of recurrent desmoid tumors by Cox proportional hazards regression. Nine of 29 patients who underwent surgical resection of recurrent desmoid tumor developed a second recurrence. Larger size of recurrent tumor was associated with increased risk of second recurrence (hazard ratio, 1.09; P?=?0.006). Treatment of the primary tumor with adjuvant radiation therapy also increased risk of re-recurrence (3.41; P?=?0.032). Second recurrence of desmoid-type fibromatosis after surgical resection is, much like recurrence of primary desmoid tumor, difficult to predict with current prognostic indicators. PMID:25916970
Is acute recurrent pancreatitis a chronic disease?
Mariani, Alberto; Testoni, Pier Alberto
2008-01-01
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 a...
Recurrent Network Models for Kinematic Tracking
Fragkiadaki, Katerina; Levine, Sergey; Malik, Jitendra
2015-01-01
We propose the Encoder-Recurrent-Decoder (ERD) model for recognition and prediction of human body pose in videos and motion capture. The ERD model is a recurrent neural network that incorporates nonlinear encoder and decoder networks before and after recurrent layers. We test instantiations of ERD architectures in the tasks of motion capture (mocap) generation, body pose labeling and body pose forecasting in videos. Our model handles mocap training data across multiple subje...
RECURRENT STROKE: WHAT HAVE WE LEARNT?
EM Khoo; Rabia K
2007-01-01
Stroke is the third leading cause of death, a major cause of disability in adults, and is frequently more disabling than fatal. With a decline in mortality from initial cerebral infarction and an increase in the life expectancy of the population, the number of patients with recurrent stroke and ensuing cardiovascular events will become greater. Thus it is important to find out those patients at high risk of stroke recurrence. This case report illustrates the process of recurrent stroke and th...
Recurrent Pyogenic Cholangitis Treated by Left Hepatectomy
Ray, Sukanta
2011-01-01
Recurrent pyogenic cholangitis is managed mostly by conservative treatment or by clearance of stones and biliary enteric by-pass procedure. Hepatectomy is rarely needed. We report a case of recurrent pyogenic cholangitis in a 34-year old man, who presented with recurrent upper abdominal pain, mild jaundice, and fever since childhood. Contrast enhanced computed tomography of abdomen and magnetic resonance cholangiopancreatography confirmed the diagnosis and showed significant atrophy of the le...
Prevention of postoperative recurrence of Crohn's disease
Van Loo, ES; Dijkstra, G.; Ploeg, RJ; Nieuwenhuijs, VB
2012-01-01
Background: Up to 75% of patients with Crohn's disease (CD) will have intestinal resection during their life. Most patients will, however, develop postoperative recurrence (endoscopic, clinical or surgical). Several medical and surgical strategies have been attempted to prevent postoperative recurrence. This review evaluates the efficacy of different drug regimens and surgical techniques in the prevention of clinical, endoscopic and surgical postoperative recurrence of CD. Methods: A literatu...
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.
Recurrent odontogenic keratocyst within the masticatory space
International Nuclear Information System (INIS)
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.
Multilayer PVD coatings for wear protection
Energy Technology Data Exchange (ETDEWEB)
Holleck, H. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Materialforschung; Schier, V. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Materialforschung
1995-11-01
The PVD technology is well suited to realize new and advanced coating concepts like gradient coatings, metastable coatings, multicomponent coatings, multilayer or superlattice coatings. Among these coating concepts the multilayer coatings seem to be the most promising concept because it meets many requirements (e.g. multifunctional character, moderate residual stresses, good adherence to metallic substrates, proper hardness to toughness ratio and low friction coefficients) for a composite exposed to complex wear conditions. Further the concept allows metastable and multicomponent materials to be introduced in a graded multilayer arrangement. By this way different layer concepts can be realized simultaneously. A functional and a structural design, taking into account the material selection for the individual layers, the adjustment of the interface volume and constitution and the optimization of the individual layer sequence and thickness, allows a tailoring of properties and performance. Covalent or ionic materials like B{sub 4}C, SiC, Si{sub 3}N{sub 4} or Al{sub 2}O{sub 3} can be introduced as intermediate layers in the multilayer arrangement, raising hardness and high temperature strength without reducing adherence or toughness of the coating. New results concerning constitution, properties and application characteristics for multilayer coatings mainly based on TiC/TiN are presented. (orig.)
Joint network design in multilayer networks
Zhu, Guolong; Zeng, Qingji; Ye, Tong; Yang, Junjie
2004-04-01
The demand to carry large amount of data as fast and as reliably as possible is continuously increasing, in parallel with formation of the information society. Nowadays, Fiber optic cables using Wavelength Division Multiplexing (WDM) are used to provide huge transport capability to support such demand effectively and economically. Each link is able to carry huge amount of traffic, thus a possible failure causes loss of tremendous data. So network survivability is highly required for such a high speed and huge capacity network. The operation of the modern telecommunication network is based on a multi-layer structure. The major reason of this multi-layer is the multiplexing hierarchy for efficient use of transmission facilities and the convenience of service and facility management. The most common example of multi-layer telecommunication network is the ATM over SDH over WDM configuration. This work investigates to the survivability of such multi-layer networks, and an integrated spare capacity dimensioning scheme, joint network design (JND) method, is proposed. Compared with single layer design (SLD) method, JND is bandwidth efficient and cost effective. The configuration problem of multi-layer fault tolerant networks is formulated as an Integer Linear Programming model. We also present a genetic algorithm approach for large networks whose size makes the ILP model difficult to use.
A degree centrality in multi-layered social network
Bródka, Piotr; Skibicki, Krzysztof; Kazienko, Przemys?aw; Musia?, Katarzyna
2012-01-01
Multi-layered social networks reflect complex relationships existing in modern interconnected IT systems. In such a network each pair of nodes may be linked by many edges that correspond to different communication or collaboration user activities. Multi-layered degree centrality for multi-layered social networks is presented in the paper. Experimental studies were carried out on data collected from the real Web 2.0 site. The multi-layered social network extracted from this d...
Magnetic damping in magnetic multilayers
International Nuclear Information System (INIS)
Full text: Magnetic multilayers provide a special case where dynamic interactions between the itinerant electrons and the magnetic moments in ultrathin films offer new possibilities compared to bulk materials. The precessing magnetization acts as a peristaltic spin pump, which transports the spin momentum away from the ferromagnet (F). In contrast to the well-known oscillatory exchange interaction in the ground state, this coupling is dynamical in nature and long ranged. In magnetic bilayers F/N/F, the transverse component of the spin current in non-magnetic spacer, N, is entirely absorbed at the N/F interface. This means that the N/F interface acts as an ideal spin sink providing an effective spin brake for the opposite ferromagnetic layer F, which results in an additional magnetic interface damping that obeys the Gilbert phenomenology. Experimental studies have been carried out using crystalline Au/Fe/Au/Fe/GaAs(001), Pd/Fe/GaAs(001), and Au/Fe/Au/Pd/Fe/GaAs(001) multilayers. The quantitative comparison with spin pumping theory is very good for Fe/Au/Fe structures. First principles electron band calculations of the spin mixing conductance ??? result in Gilbert damping, which is in a nearly perfect agreement with the measured non-local, interface damping. The spin transport across Pd spacers is different compared to that in Au spacers. The spin current is strongly attenuated by interaction with fluctuating moment in Pd. The propagation of the spin current becomes more complex in heterogeneous Pd/Au spacers. It will be shown that the propagation of the spin current in Pd/Au (001) spacers is affected by a partial reflection of spin current at the Pd/Au interface. The Pd lattice has a large lattice mismatch with respect to Fe. For the Pd layers thicker than 5ML the lattice strain is partially released by a rectangular network of misfit dislocations. It will be shown that the formation of a self-assembled nano network of misfit dislocations leads to a strong extrinsic magnetic damping. The out of plane measurements of the FMR linewidth have revealed that the extrinsic damping is caused by two magnon scattering. This system provides an ideal opportunity to investigate the role of two magnon scattering in a wide range of microwave frequencies. FMR measurements were carried out from 4 GHz to 73 GHz. The contribution to the FMR linewidth from two magnon scattering is strongly anisotropic and follows the rectangular symmetry of the glide planes of the misfit dislocation network. The angular dependence of the FMR linewidth is a consequence of an effective channeling of the scattered spinwaves. The extrinsic damping often results in FMR linewidth above 10GHz that increases linearly with microwave frequency but is accompanied by a zero frequency offset. Two magnon scattering in Pd/Fe systems is no exception. It will be shown that this behavior is not followed in the lower range of microwave frequencies. The FMR linewidth eventually shows a rapid decrease towards zero, resulting in a large effective Gilbert damping which can surpass the intrinsic contribution to Gilbert damping by two orders of magnitude. Corresponding Author: B. Heinrich, bheinrich at sfu.ca, 1 604 2914402
Calculation of nuclear resonant scattering spectra of magnetic multilayers
International Nuclear Information System (INIS)
Calculations of the angle- and time-dependent photon reflectivity of multilayers are presented, using the technique of characteristic matrices. Spectra of 56Fe/57Fe and Cr/57Fe multilayers are calculated under various conditions. The parameters of the multilayers are optimized for suitable test samples of reflectometry measurements. (author) 10 refs.; 6 figs
Monolayers and Langmuir-Blodgett multilayers of discotic liquid crystals?
Laschewsky, André
1989-01-01
Contents: 1. Discotic Liquid Crystals 2. Monolayers and Langmuir-Blodgett Multilayers 3. Theoretical Considerations on the Molecular Packing of Discotic LCs in Monolayers and Multilayers 4. Spreading Experiments with Discotic LCs 5. LB-Multilayers of Discotic LCs 6. Polymeric Discotic LCs 7. Summary
Chemoradiotherapy response in recurrent rectal cancer
International Nuclear Information System (INIS)
The efficacy of response to preoperative chemoradiotherapy (CRT) in recurrent versus primary rectal cancer has not been investigated. We compared radiological downsizing between primary and recurrent rectal cancers following CRT and determined the optimal size reduction threshold for response validated by survival outcomes. The proportional change in tumor length for primary and recurrent rectal cancers following CRT was compared using the independent sample t-test. Overall survival (OS) was calculated using the Kaplan–Meier product limit method and differences between survival for tumor size reduction thresholds of 30% (response evaluation criteria in solid tumors [RECIST]), 40%, and 50% after CRT in primary and recurrent rectal cancer groups. A total of 385 patients undergoing CRT were analyzed, 99 with recurrent rectal cancer and 286 with primary rectal cancer. The mean proportional reduction in maximum craniocaudal length was significantly higher for primary rectal tumors (33%) compared with recurrent rectal cancer (11%) (P < 0.01). There was no difference in OS for either primary or recurrent rectal cancer when ?30% or ?40% definitions were used. However, for both primary and recurrent tumors, significant differences in median 3-year OS were observed when a RECIST cut-off of 50% was used. OS was 99% versus 77% in primary and 100% versus 42% in recurrent rectal cancer (P = 0.002 and P = 0.03, respectively). Only patients that demonstrated >50% size reduction showed a survival benefit. Recurrent rectal cancer appears radioresistant compared with primary tumors for tumor size after CRT. Further investigation into improving/intensifying chemotherapy and radiotherapy for locally recurrent rectal cancer is justified
Magnetic studies of Fe/Cu multilayers
International Nuclear Information System (INIS)
The structural and magnetic properties of sputtered Fe/Cu multilayers are examined as a function of Fe layer thickness tFe 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 T3/2 law in all multilayers in the temperature range 5-300 K. The interface anisotropy constant of Fe/Cu multilayers, Ks, is found to be 0.31 and 0.45 erg/cm2 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 Jb, surface exchange interaction Js and the interlayer coupling strength JI for various Fe layer thicknesses have been obtained
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
Evolutionary games on multilayer networks: A colloquium
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...
Multilayer Integrated Film Bulk Acoustic Resonators
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 Education’s Key Laboratory for Thin Films and Microfabrication Technology, PRC; Dr. Da Chen was a PhD student in Prof. Yafei Zhang’s research group.
Multilayer neural networks a generalized net perspective
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...
Long Range Surface Plasmons in Multilayer Structures
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.
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
X-rays look through multilayers
International Nuclear Information System (INIS)
What was originally a one- or two-layer printed circuit-board has turned into multilayer boards of high complexity. Production of boards of this type place high requirements on production engineering and process reliability. One important quality criterion of the multilayer is e.g. a sufficient width of the copper ring around a plated-through hole, the so-called residual ring width. Printed circuit-boards can be measured exactly and scrap prevented by employing an X-ray tester with integrated image processing within the various production steps. (orig.)
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.
Interface resistance of disordered magnetic multilayers
Xia, K; Bauer, G E W; Turek, I; Kudrnovsky, J; Drchal, V
2001-01-01
We study the effect of interface disorder on the spin-dependent interface resistances of Co/Cu, Fe/Cr and Au/Ag multilayers using a newly developed method for calculating transmission matrices from first-principles. The efficient implementation using tight-binding linear-muffin-tin orbitals allows us to model interface disorder using large lateral supercells whereby specular and diffuse scattering are treated on an equal footing. Without introducing any free parameters, quantitative agreement with experiment is obtained. We predict that disorder {\\it reduces} the majority-spin interface resistance of Fe/Cr(100) multilayers by a factor 3.
Interface resistance of disordered magnetic multilayers
Xia, K.; Kelly, P. J.; Bauer, G. E.; Turek, I.; Kudrnovský, J.; Drchal, V.
2001-02-01
We study the effect of interface disorder on the spin-dependent interface resistances of Co/Cu, Fe/Cr, and Au/Ag multilayers using a newly developed method for calculating transmission matrices from first-principles. The efficient implementation using tight-binding linear-muffin-tin orbitals allows us to model interface disorder using large lateral supercells whereby specular and diffuse scattering are treated on an equal footing. Without introducing any free parameters, quantitative agreement with experiment is obtained. We predict that disorder reduces the majority-spin interface resistance of Fe/Cr(100) multilayers by a factor 3.
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.
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.
Recurrent pregnancy loss and obesity.
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
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)
Poincare recurrences and topological diversity
International Nuclear Information System (INIS)
Finite entropy thermal systems undergo Poincare recurrences. In the context of field theory, this implies that at finite temperature, timelike two-point functions will be quasi-periodic. In this note we attempt to reproduce this behavior using the AdS/CFT correspondence by studying the correlator of a massive scalar field in the bulk. We evaluate the correlator by summing over all the SL(2,Z) images of the BTZ spacetime. We show that all the terms in this sum receive large corrections after at certain critical time, and that the result, even if convergent, is not quasi-periodic. We present several arguments indicating that the periodicity will be very difficult to recover without an exact re-summation, and discuss several toy models which illustrate this. Finally, we consider the consequences for the information paradox. (author)
Recurrent gastric lactobezoar in an infant
Castro, Leonor; Berenguer, Alberto; Pilar, Carla; Gonçalves, Rute; Nunes, José L.
2014-01-01
Lactobezoars are a type of bezoar composed of undigested milk and mucus. The aetiology is likely multifactorial, being classically described in association with pre-term, low-birth weight infants fed with hyperconcentrated formula. The authors present a case of lactobezoar recurrence in a pre-term infant with oesophageal atresia. To our knowledge, this is the first report of recurrence of lactobezoar.
Lesson Learned from (some) Recurrent Novae
Mason, E.; Walter, F. M.
2014-12-01
In this talk we present early decline and nebular spectra of the recurrent novae YY Dor and nova LMC 2009. These and a few other recurrent novae of the same type, share similar spectral characteristics and evolution. We will discuss those common features critically suggesting same white dwarf progenitor and post outburst phases for all of them.
Lesson learned from (some) recurrent novae
Mason, Elena
2013-01-01
In this talk we present early decline and nebular spectra of the recurrent novae YY Dor and nova LMC 2009. These and a few other recurrent novae of the same type, share similar spectral characteristics and evolution. We will critically discuss those common features suggesting same white dwarf progenitor and post outburst phases for all of them.
Ocean wave forecasting using recurrent neural networks
Digital Repository Service at National Institute of Oceanography (India)
Mandal, S.; Prabaharan, N.
2006-01-01
Marmugao, west coast of India are used for this study. Here, the recurrent neural network of 3, 6 and 12 hourly wave forecasting yields the correlation coefficients of 0.95, 0.90 and 0.87 respectively. This shows that the wave forecasting using recurrent...
Recurrent Bilateral Breast Abscesses after Sternotomy
Hamza Cinar; Ali Naki Ulusoy; Emir Fatih Kaya; Gökhan Lap; Kagan Karabulut; Ayfer Kamal? Polat; Gökhan Selcuk Özbalci
2012-01-01
Median sternotomy is the most commonly used incision in cardiothoracic procedures. Development of breast abscess after sternotomy is a very rare situation. We present a case of sternal wound infection with recurrent bilateral breast abscess after sternotomy. Our case is the first and only case in the literature due to the presence of sternal wound infection with recurrent bilateral breast abscess after sternotomy.
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
A case of seven recurrent ectopic pregnancies.
Shakeel A. Faiz; Bengt G. Sporrong; Abdulaziz A. Al-Meshari
2003-01-01
ABSTRACT If a woman with previous ectopic pregnancy ever gets pregnant again, the risk of a repeat ectopic pregnancy is said to be 4-fold. We present a rare case of 7 recurrent ectopic pregnancies in a 39-year-old Saudi woman, together with a literature review of the reproductive performance after recurrent ectopic pregnancy.
Recurrence in Major Depression: A Conceptual Analysis
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…
Recurrent Malignant Pleural Mesothelioma: Case Report
Denton A Cooley; Frazier, O Howard
1983-01-01
A 42-year-old woman with malignant pleural mesothelioma was admitted initially to the Texas Heart Institute in 1967 for removal of a chest wall tumor. She subsequently underwent 17 additional thoracotomies for removal of recurrent localized tumor during a 15-year period. She died in 1982 at age 56 from cardiopulmonary failure secondary to extensive recurrent mesothelioma.
Chemoradiotherapy of unresectable and recurrent cholangiocarcinoma
International Nuclear Information System (INIS)
This study is for chemoradiotherapy of unresectable and recurrent cholangiocarcinoma (CCC). Between April 2005 and March 2007, 5 patients were evaluated for unresectable and recurrent CCC. All patients were performed percutaneous transhepatic biliary drainage (PTBD) and treated with chemoradiotherapy. The radiation method was an external beam radiotherapy (EBRT) and remote after loading system (RALS). The chemotherapy was 5-fluorouracil (FU) and gemcitabine by intravenous injection. Three patients had unresectable and 2 had recurrent CCC. As for the side effects, 4 patients had a slight neutropenia and 1 had an uncontrollable gastric bleeding. No patient had cholangitis. The mean survival time for unresectable and recurrent CCC was 13.7 months and 17 months, respectively. Our results indicated that chemoradiotherapy had been consistent with efficacy in patients with unresectable and recurrent CCC. (author)
MR imaging characteristics of recurrent thyroid tumors
International Nuclear Information System (INIS)
MR imaging was used to evaluate 32 patients after partial or total thyroidectomy. Surgical (n = 25) or clinical (n = 7) follow-up was done. Of 23 patients with primary thyroid carcinomas, MR imaging disclosed recurrence in 15 and no recurrence in eight. There were two false-positive diagnoses and one false-negative diagnosis. Nine patients who had undergone surgery for benign disease were studied to assess the appearance of the thyroid bed after thyroidectomy. Local recurrence of carcinoma was characterized by low to medium signal intensity on T1-weighted images and medium to high signal intensity on T2-weighted images. Scar tissue has low intensity. Coronal and sagittal images provided definition of local and mediastinal extension and metastasis. Thus, MR imaging can be used to evaluate recurrence of thyroid tumors and to differentiate recurrence from postoperative fibrosis
Diffraction gratings based on asymmetric-cut multilayers
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.
EduXs: Multilayer Educational Services Platforms
Chang, Li-Jie; Yang, Jie-Chi; Deng, Yi-Chan; Chan, Tak-Wai
2003-01-01
How to use the online social learning communities to improve quality and quantity of interactions in physical social learning communities is an important issue. This work describes the design and implementation of multilayer educational services platforms that enable learners to establish their own online social learning communities and integrate…
Diffraction Gratings Based on Multilayer Structures
International Science & Technology Center (ISTC)
Development of High Efficiency Diffraction Gratings on the Basis of Multilayer Structures for Monochromators and Polychromators of X-Ray Synchrotron Radiation and for Ultra-High Spectral Resolution X-Ray Diagnostics in the 0.1 – 10 Kev Energy Range
Surface immobilized protein multilayers for cell seeding.
Czech Academy of Sciences Publication Activity Database
Brynda, Eduard; Pacherník, J.; Houska, Milan; Pientka, Zbyn?k; Dvo?ák, P.
2005-01-01
Ro?. 21, ?. 17 (2005), s. 7877. ISSN 0743-7463 R&D Projects: GA ?R(CZ) GA203/02/1326; GA ?R 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
Electronic excitations of the multilayered graphite
International Nuclear Information System (INIS)
Electronic excitations of the multilayered graphite are studied within the random-phase approximation. The loss function, which characterizes the intrinsic excitation spectrum, is derived in details. The interlayer atomic hopping integrals and the interlayer e-e Coulomb interactions are taken into account simultaneously. They could create new plasmon modes and e-h excitation channels
Thermal mixing of Al-Fe multilayers
International Nuclear Information System (INIS)
Al-Fe multilayers have been mixed by thermal treatment and their evolution followed by conversion electron Moessbauer spectroscopy. The initial and final states have been characterized by Rutherford backscattering spectrometry. The results are compared with those previously obtained in the ion beam mixing of similar systems. (orig.)
Analysis of Fracture Behaviour of Multilayer Pipes.
Czech Academy of Sciences Publication Activity Database
Nezbedová, E.; Knésl, Zden?k; Vlach, B.
2007-01-01
Ro?. 36, ?. 5 (2007), s. 207-212. ISSN 1465-8011. [Plastic Pipes /13./. Washington, D. C., 02.10.2006-05.10.2006] R&D Projects: GA ?R 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
Transmission fingerprints in quasiperiodic magnonic multilayers
Energy Technology Data Exchange (ETDEWEB)
Coelho, I.P. [Departamento de Ensino Superior, Instituto Federal de Educacao, Ciencia e Tecnologia do Maranhao, Imperatriz-MA 65919-050 (Brazil); Departamento de Fisica, Universidade Federal do Rio Grande do Norte, Natal-RN 59072-970 (Brazil); Vasconcelos, M.S. [Escola de Ciencias e Tecnologia, Universidade Federal do Rio Grande do Norte, Natal-RN 59072-970 (Brazil); Bezerra, C.G., E-mail: cbezerra@dfte.ufrn.br [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, Natal-RN 59072-970 (Brazil)
2011-12-15
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 J{sub A} and J{sub B} and spin quantum numbers S{sub A} and S{sub B}, respectively. The multilayer structure is surrounded by two semi-infinite slabs of a third Heisenberg ferromagnetic material with exchange constant J{sub C} and spin quantum number S{sub C}. 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.
Thermal Transport in Graphene and Graphene Multilayers
Balandin, Alexander A.; Nika, Denis L.
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.
Flint, Alex; Blaschko, Matthew
2012-01-01
Boolean satisfiability (SAT) as a canonical NP-complete decision problem is one of the most important problems in computer science. In practice, real-world SAT sentences are drawn from a distribution that may result in efficient algorithms for their solution. Such SAT instances are likely to have shared characteristics and substructures. This work approaches the exploration of a family of SAT solvers as a learning problem. In particular, we relate polynomial time solvability of a SAT subset t...
Endoscopic surgery for recurrent undifferentiated nasopharyngeal carcinoma.
Emanuelli, Enzo; Albu, Silviu; Cazzador, Diego; Pedruzzi, Barbara; Babighian, Gregorio; Martini, Alessandro
2014-05-01
One of the biggest challenges for otolaryngologists is represented by the locally recurrent undifferentiated nasopharyngeal carcinoma (uNPC). Despite improvements in its treatment options, such as modern radiotherapy, chemotherapy, or external surgical approaches, the risk for severe complications, functional disabilities, and even death remains considerable. Over the years, advances in endoscopic surgery have led to a new alternative in the salvage surgery for recurrent uNPC: the nasopharyngeal endoscopic resection (NER). We retrospectively reviewed clinical records of 8 patients (6 men and 2 women), who underwent NER for recurrent T1 (rT1) locally recurrent uNPC between 2008 and 2011. Together with resections for subsequent recurrences, a total of 9 NERs were performed by a single surgeon with curative intent. Negative margins were obtained for the whole group of patients. After a mean follow-up period of 27 months (range, 16-54 mo), all the patients had no evidence of the disease. We had only 1 recurrence after 7 months. Two-year overall survival and disease-free survival rates were 100% and 88.9%, respectively. Only 1 patient presented with a complication, osteitis. Nasopharyngeal endoscopic resection can be considered a valid and promising treatment option for rT1 locally recurrent uNPC, showing encouraging short-term outcomes and complication rate. Long-term follow-up is needed to state the efficacy of NER, together with a larger number of patients. PMID:24670277
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.
Sallinen, Ville; Mali, Juha; Leppäniemi, Ari; Mentula, Panu
2015-02-01
Recurrence of acute diverticulitis is common, and--especially complicated recurrence--causes significant morbidity. To prevent recurrence, selected patients have been offered prophylactic sigmoid resection. However, as there is no tool to predict whose diverticulitis will recur and, in particular, who will have complicated recurrence, the indications for sigmoid resections have been variable. The objective of this study was to identify risk factors predicting recurrence of acute diverticulitis. This is a retrospective cohort study of patients presenting with computed tomography-confirmed acute diverticulitis and treated nonresectionally during 2006 to 2010. Risk factors for recurrence were identified using uni- and multivariate Cox regression. A total of 512 patients were included. History of diverticulitis was an independent risk factor predicting uncomplicated recurrence of diverticulitis (1-2 earlier diverticulitis HR 1.6, 3 or more--HR 3.2). History of diverticulitis (HR 3.3), abscess (HR 6.2), and corticosteroid medication (HR 16.1) were independent risk factors for complicated recurrence. Based on regression coefficients, risk scoring was created: 1 point for history of diverticulitis, 2 points for abscess, and 3 points for corticosteroid medication. The risk score was unable to predict uncomplicated recurrence (AUC 0.48), but was able to predict complicated recurrence (AUC 0.80). Patients were further divided into low-risk (0-2 points) and high-risk (>2 points) groups. Low-risk and high-risk groups had 3% and 43% 5-year complicated recurrence rates, respectively. Risk for complicated recurrence of acute diverticulitis can be assessed using risk scoring. The risk for uncomplicated recurrence increases along with increasing number of previous diverticulitis. PMID:25715253
What Is an Earthquake?: Recurrence Interval
This activity consists of two exercises on determining recurrence interval; one, a hypothetical example, and the other, using real data from the San Andreas Fault. They provide the learner with a good idea of how valuable the concept can be in assessing earthquake hazards, and of a few of the problems associated with determining and correctly applying recurrence intervals in fault studies. The learner is familiarized with the concept of recurrence interval, and several different ways to determine this value for a given fault. There is also a graphing exercise that looks at real-world data from studies made on the San Andreas fault.
RECURRENT STROKE: WHAT HAVE WE LEARNT?
Directory of Open Access Journals (Sweden)
EM Khoo
2007-01-01
Full Text Available Stroke is the third leading cause of death, a major cause of disability in adults, and is frequently more disabling than fatal. With a decline in mortality from initial cerebral infarction and an increase in the life expectancy of the population, the number of patients with recurrent stroke and ensuing cardiovascular events will become greater. Thus it is important to find out those patients at high risk of stroke recurrence. This case report illustrates the process of recurrent stroke and the resulting disabilities and morbidities in a 42-year- old man. The role of integrated stroke rehabilitation programme is described.
Prevention of Recurrent Staphylococcal Skin Infections.
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
Generalised Recurrence Plot Analysis for Spatial Data
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.
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.
Urban legends: recurrent aphthous stomatitis.
Baccaglini, L; Lalla, R V; Bruce, A J; Sartori-Valinotti, J C; Latortue, M C; Carrozzo, M; Rogers, R S
2011-11-01
Recurrent aphthous stomatitis (RAS) is the most common idiopathic intraoral ulcerative disease in the USA. Aphthae typically occur in apparently healthy individuals, although an association with certain systemic diseases has been reported. Despite the unclear etiopathogenesis, new drug trials are continuously conducted in an attempt to reduce pain and dysfunction. We investigated four controversial topics: (1) Is complex aphthosis a mild form of Behçet's disease (BD)? (2) Is periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome a distinct medical entity? (3) Is RAS associated with other systemic diseases [e.g., celiac disease (CD) and B12 deficiency]? (4) Are there any new RAS treatments? Results from extensive literature searches, including a systematic review of RAS trials, suggested the following: (1) Complex aphthosis is not a mild form of BD in North America or Western Europe; (2) Diagnostic criteria for PFAPA have low specificity and the characteristics of the oral ulcers warrant further studies; (3) Oral ulcers may be associated with CD; however, these ulcers may not be RAS; RAS is rarely associated with B12 deficiency; nevertheless, B12 treatment may be beneficial, via mechanisms that warrant further study; (4) Thirty-three controlled trials published in the past 6 years reported some effectiveness, although potential for bias was high. PMID:21812866
Polyelectrolyte multilayers: An odyssey through interdisciplinary science
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 45°C, 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 55°C. 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
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.
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
Postoperative recurrence after VATS for spontaneous pneumothorax
International Nuclear Information System (INIS)
A total of 88 cases of 81 patients with spontaneous pneumothorax treated at the hospital from March 1992 to August 2001 were subjected to a study of examining preoperative chest CT and thoracographic findings from the standpoint of postoperative recurrence. Preoperative chest CT and thoracography were conducted in 82 cases and 41 cases (including 25 cases with continuous air leakage), respectively. Eight (9.1%) patients developed recurrence of pneumothorax, and three patients of them underwent reoperation. Considering the intraoperative findings, newly formed bullae appeared to be a cause of recurrence. Resulting from these examinations, we conclude that it is difficult to predict the risk factor for postoperative recurrence at this time, in addition, it is important that the area of air leakage can be confirmed by thoracoscopic findings. (author)
Broncholithiasis presenting as bronchiectasis and recurrent pneumonias.
Dakkak, Melissa; Siddiqi, Furqan; Cury, James Davis
2015-01-01
A broncholith is defined as the presence of calcified material within a bronchus or within a cavity communicating with a bronchus. It is most frequently caused by Histoplasmosis or tuberculosis (TB) spp. Bronchial distortion, irritation and erosion by broncholiths can cause bronchiectasis, recurrent pneumonias and haemoptysis. We present a case of recurrent pneumonia due to a broncholith, which resolved conservatively with antibiotics. Owing to recurrent fevers and post obstructive pneumonias, a lobectomy or rigid bronchoscopic removal were considered but the patient was deemed not to be a candidate for general anaesthesia due to her comorbidities. Broncholiths are an uncommon cause of bronchiectasis and recurrent pneumonias. However, the wide range of symptoms and low clinical suspicion are the main reasons why a diagnosis can be delayed. Various treatment options are available and the choice of therapy should be made depending on the broncholith's size, mobility, location and local surgical expertise. PMID:26106172
Forequarter amputation for recurrent breast cancer
Pundi, Krishna N.; AlJamal, Yazan N.; Ruparel, Raaj K.; Farley, David R.
2015-01-01
•Forequarter amputation is an aggressive treatment for recurrent breast cancer.•Some patients with regional metastatic disease do benefit from forequarter amputation.•Patients with unrelenting cancer pain do gain relief from forequarter amputation.
Familial recurrence of congenital heart diseases.
Thammineni, K; Lohr, J; Trefz, M; Sivanandam, S
2011-11-01
Familial recurrence of congenital heart disease (CHD), in particular, d-transposition of great arteries (d-TGA) is rare. However, there have been several reports in the literature of sibling recurrence of total anomalous pulmonary venous return (TAPVR). This is the first case report in the literature, describing mother to offspring recurrence of d-TGA. We describe two cases of non-syndromic CHD with mother to offspring and sibling recurrence. The first case is an antenatally diagnosed d-TGA on fetal echocardiogram at 25 weeks of gestational age in the offspring of a 30-year-old mother with d-TGA. The second case is a sibling reoccurrence of TAPVR diagnosed antenatally at 30 weeks of gestational age, with supradiaphragmatic TAPVR on fetal echocardiogram in a mother, whose first child was diagnosed with infradiaphragmatic TAPVR in infancy. PMID:22037157
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.)
Recurrence quantification analysis theory and best practices
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.
Chondrosarcoma of the Maxilla-Recurrent
Directory of Open Access Journals (Sweden)
Aniece Chowdhary, Parmod Kalsotra, Des Raj Bhagat, Poonam Sharma*, Pervez Katoch**
2008-04-01
Full Text Available An uncommon case of recurrent chondrosarcoma of the maxilla is presented. A brief discussion on theradiologic and histologic presentation of the tumor and the treatment modalities of this unusual tumor isdiscussed.
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.
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
Design and development of multilayer vascular graft
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.
Risk factors that affect recurrence in strokes
Directory of Open Access Journals (Sweden)
Sevim Bayba?
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 Bak?rkoy 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.
FDG-PET probe-guided surgery for recurrent retroperitoneal testicular tumor recurrences
de Jong, J S; 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...
Recurrent gastric lactobezoar in an infant.
Castro, Leonor; Berenguer, Alberto; Pilar, Carla; Gonçalves, Rute; Nunes, José L
2014-07-01
Lactobezoars are a type of bezoar composed of undigested milk and mucus. The aetiology is likely multifactorial, being classically described in association with pre-term, low-birth weight infants fed with hyperconcentrated formula. The authors present a case of lactobezoar recurrence in a pre-term infant with oesophageal atresia. To our knowledge, this is the first report of recurrence of lactobezoar. PMID:25988036
Recurrent Multifocal Primary Amyloidosis of Urinary Bladder
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Patel S
2008-01-01
Full Text Available Primary localized amyloidosis of bladder is rare. We report a case of recurrence of multifocal primary amyloidosis of urinary bladder. Cystoscopy revealed a diffuse left lateral wall lesion with normal surrounding mucosa. Histopathological examination of the specimen revealed urinary bladder amyloidosis with negative surgical margins. Recurrent urinary bladder amyloidosis was confirmed 3 months after the first resection. Close follow-up is recommended.
International Nuclear Information System (INIS)
On the example of a hard-disk system the non-recurrence problem have been investigated. Some of the properties of differential equation for the motion of hard-disk system have been analyzed. Using the suggestions of all disk pairs occur simultaneously within a rather small period ?, asymptotic properties of the non-equilibrium hard-disk system when t?? have been studied. The explanation of non-recurrence nature have been submitted. (author)
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
Recurrent Respiratory Papillomatosis: an Extensive Review
Angelou Valerie; Kalodimou E. Vasiliki
2012-01-01
Recurrent respiratory papillomatosis (RRP) is characterized by the recurrence of benign tumors (papillomata) in the aero digestive tract caused by Human Papilloma Virus. The burden for the patient and the society is non negligible, due to the high frequency of repetitive surgeries. The disease follows a bimodal age distribution. Usually the very first manifestation is hoarseness or voice changes but if negligee it can cause airway obstruction resulting in respiratorystridor or acute resp...
Laboratory constraints on models of earthquake recurrence
Beeler, N. M.; Tullis, Terry; Junger, Jenni; Kilgore, Brian; Goldsby, David
2014-12-01
In this study, rock friction "stick-slip" experiments are used to develop constraints on models of earthquake recurrence. Constant rate loading of bare rock surfaces in high-quality experiments produces stick-slip recurrence that is periodic at least to second order. When the loading rate is varied, recurrence is approximately inversely proportional to loading rate. These laboratory events initiate due to a slip-rate-dependent process that also determines the size of the stress drop and, as a consequence, stress drop varies weakly but systematically with loading rate. This is especially evident in experiments where the loading rate is changed by orders of magnitude, as is thought to be the loading condition of naturally occurring, small repeating earthquakes driven by afterslip, or low-frequency earthquakes loaded by episodic slip. The experimentally observed stress drops are well described by a logarithmic dependence on recurrence interval that can be cast as a nonlinear slip predictable model. The fault's rate dependence of strength is the key physical parameter. Additionally, even at constant loading rate the most reproducible laboratory recurrence is not exactly periodic, unlike existing friction recurrence models. We present example laboratory catalogs that document the variance and show that in large catalogs, even at constant loading rate, stress drop and recurrence covary systematically. The origin of this covariance is largely consistent with variability of the dependence of fault strength on slip rate. Laboratory catalogs show aspects of both slip and time predictability, and successive stress drops are strongly correlated indicating a "memory" of prior slip history that extends over at least one recurrence cycle.
PET Imaging in Recurrent Medullary Thyroid Carcinoma
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...
Solving recurrence relations supported by Wolfram Mathematica
Directory of Open Access Journals (Sweden)
Enrique Vílchez-Quesada
2015-01-01
Full Text Available This paper introduces some algorithms for solving linear relationships, homogeneous and non-homogeneous recurrence with constant and non-constant coefficients, using software as the main resource in solving processes. The Mathematica commercial application has provided the technical support necessary for the implementation of the methods used. It also presents other examples of recurrence relations, showing the effectiveness and limitations of the algorithms created by the author and programmed in Mathematica environment that provides.
Surgical treatment for residual or recurrent strabismus
WANG, TAO; Wang, Li-Hua
2014-01-01
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 su...
Par-4 prevents breast cancer recurrence
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.
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)
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 margiage, EIC-comedo status, the surgical margin, and negative ER status were correlated with breast recurrence. Countermeasures against these factors should be investigated. (author)
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.
Mathematical Formulation of Multi-Layer Networks
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...
The structure and dynamics of multilayer networks
Boccaletti, S; Criado, R; del Genio, C I; Gómez-Gardeñes, J; Romance, M; Sendiña-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...
The structure and dynamics of multilayer networks
Boccaletti, S.; Bianconi, G.; Criado, R.; del Genio, C. I.; Gómez-Gardeñes, J.; Romance, M.; Sendiña-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.
Mo-C Multilayered CVD Coatings
Directory of Open Access Journals (Sweden)
A. Sagalovych
2013-12-01
Full Text Available Production processes of multi-layered Mo-C coatings by the method of chemical vapor deposition (CVD with the use of organometallic compounds were developed. Coatings are applied on technical purpose steel DIN 1.2379 (H12F1 and DIN 1.7709 (25H2MF (ÉI10 heat-treated ball with the high class of surface roughness (> 10. The average deposition rate was 50 ?m / h. The optimal conditions of deposition coatings for different technological schemas were defined. Metallographic investigations of the obtained coatings were carried out. Tribological studies of the friction and wear characteristics of sliding friction in conditions of boundary lubrication of Ï-S multilayered CVD coatings shows, that coatings have low friction coefficients (0075-0095 at loads up to 2.0 kN, showed high resistance to wear and are effective in increasing the stability of the pair for precision friction pairs of hydraulical units.
Optical model for multilayer glazing systems
International Nuclear Information System (INIS)
In the design phase of a glazing system, multiple laminated glass configurations may be conceived for various architectural purposes (mainly related to aesthetical issues, energy efficiency, safety and security and/or acoustic insulation). Therefore, the availability of computational simulations of optical and thermal properties of laminated glass as a function of the properties of its constituents (glass panes, polymeric films, selective coatings) may be of great utility. Standardised procedures for this kind of calculations are still being prepared by CEN (European Committee for Standardization). The theoretical study of laminated glass with internal selective coatings is especially relevant due to the introduction of reflectivity within the multilayer optical system. Here, a theoretical model based on transfer matrix method and applied to multilayer glazing with external and internal coatings is presented. Simulation results are compared with UV-VIS-NIR spectrophotometric measurements. (Author)
Random walk centrality in interconnected multilayer networks
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.
Magnetic nanodiscs fabricated from multilayered nanowires.
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
Information Propagation in Clustered Multilayer Networks
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...
EUV Ellipsometry on Mo/Si Multilayers
Uschakow, S.; Gaupp, A.; MacDonald, M.; Schäfers, F.
2013-03-01
We investigate polarisation properties of a reflective Mo/Si multilayer system in the EUV range using polarized synchrotron radiation at BESSY-II. The characterization involves reflectivity measurements with s- and p-polarized light as a function of the wavelength for three different angles near normal incidence. The phase retardance is determined near normal incidence for one fixed angle of incidence as a function of the wavelength. As an additional spin-off of the polarimetry measurement the Stokes parameters of the beamline could be determined. With the 8-axis UHV-polarimeter we have measured the complex reflection coefficients for the first time and establish this ellipsometry technique as an additional sensitive probe to characterize and model multilayer optical elements.
Growth and characterisation on giant magnetoresistance property of metallic multilayers
International Nuclear Information System (INIS)
Metallic multilayers with specific materials configurations have been shown to exhibit giant magnetoresistance effect at room temperature. In this study, microstructural analysis was carried out on magnetron sputtered Co/Cu multilayers using various diffraction and imaging techniques. Dominant characteristic features associated with the multilayers, such as lateral and vertical columnar grain orientations as well as layer undulation and regularity were identified. By deliberately introducing microstructural changes using a buffer layer and via heat treatment, detailed microstructural analysis carried out on the multilayers has provided an insight into the dependence of giant magnetoresistance on the observed microstructures. Our study shows that high giant magnetoresistance effect of the multilayers was associated with highly correlated interfacial profiles, sharp columnar grain boundaries and high degree of lateral coherency in columnar grain growth. While the introduction of iron buffer layer favored the growth of these structural features that were responsible for large giant magnetoresistance effect, annealing led to deterioration of giant magnetoresistance property of the multilayers. (Author)
An ensemble perspective on multi-layer networks
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.
Development of multilayered chitosan-based nanofibers
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...
Principles of Bragg-Fresnel multilayer optics
International Nuclear Information System (INIS)
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
Multilayer coatings monitoring using admittance diagram.
Lee, Cheng-Chung; Chen, Yu-Jen
2008-04-28
A method based on admittance diagram called Admittance Real-time Monitoring, ARM, was proposed to monitor multilayer coatings. This optical monitoring method is highly sensitive and capable to compensate for thickness errors. The sensitivities of ARM were compared with that of the conventional method by using runsheet diagram. The in situ error compensation of ARM showed a great improvement in the optical performance when utilized in an anti-reflection coating process. PMID:18545313
Fracture mechanics parameters of multilayer pipes.
Czech Academy of Sciences Publication Activity Database
Šestáková, Lucie; Náhlík, Luboš; Huta?, Pavel; Knésl, Zden?k
2007-01-01
Ro?. 1, ?. 1 (2007), s. 299-306. ISSN 1802-680X. [Výpo?tová mechanika 2007. Hrad Ne?tiny, 05.11.2007-07.11.2007] R&D Projects: GA ?R GA101/05/0227; GA ?R GD106/05/H008 Institutional research plan: CEZ:AV0Z20410507 Keywords : multilayer pipes * K-calibration * T-stress * finite element method Subject RIV: JL - Materials Fatigue, Friction Mechanics
Toughening mechanisms in bioinspired multilayered materials.
Askarinejad, Sina; Rahbar, Nima
2015-01-01
Outstanding mechanical properties of biological multilayered materials are strongly influenced by nanoscale features in their structure. In this study, mechanical behaviour and toughening mechanisms of abalone nacre-inspired multilayered materials are explored. In nacre's structure, the organic matrix, pillars and the roughness of the aragonite platelets play important roles in its overall mechanical performance. A micromechanical model for multilayered biological materials is proposed to simulate their mechanical deformation and toughening mechanisms. The fundamental hypothesis of the model is the inclusion of nanoscale pillars with near theoretical strength (?th ~ E/30). It is also assumed that pillars and asperities confine the organic matrix to the proximity of the platelets, and, hence, increase their stiffness, since it has been previously shown that the organic matrix behaves more stiffly in the proximity of mineral platelets. The modelling results are in excellent agreement with the available experimental data for abalone nacre. The results demonstrate that the aragonite platelets, pillars and organic matrix synergistically affect the stiffness of nacre, and the pillars significantly contribute to the mechanical performance of nacre. It is also shown that the roughness induced interactions between the organic matrix and aragonite platelet, represented in the model by asperity elements, play a key role in strength and toughness of abalone nacre. The highly nonlinear behaviour of the proposed multilayered material is the result of distributed deformation in the nacre-like structure due to the existence of nano-asperities and nanopillars with near theoretical strength. Finally, tensile toughness is studied as a function of the components in the microstructure of nacre. PMID:25551150
Plasmonic waveguides with hyperbolic multilayer cladding
Babicheva, Viktoriia E.; Shalaginov, Mikhail Y.; Ishii, Satoshi; Boltasseva, Alexandra; Kildishev, Alexander V.
2014-01-01
Engineering plasmonic metamaterials with anisotropic optical dispersion enables us to tailor the properties of metamaterial-based waveguides. We investigate plasmonic waveguides with dielectric cores and multilayer metal-dielectric claddings with hyperbolic dispersion. Without using any homogenization, we calculate the resonant eigenmodes of the finite-width cladding layers, and find agreement with the resonant features in the dispersion of the cladded waveguides. We show th...
How would nanostructures emerge in stressed multilayers?
Colin, J.; Grilhé, J.; D'Anterroches, C.; Misbah, C.
2006-08-01
We study theoretically the emergence of nanostructures in stressed multilayers. A non-linear amplitude expansion provides us with a simple argument on how the nanostructures emerging at the interfaces of the materials should behave. The criterion is simply expressed in terms of the relative elastic hardness of the solids. This study should serve as a guide to design new nano-architectures, a problem of much current interest.
Numerical modeling of multilayer pipes fracture.
Czech Academy of Sciences Publication Activity Database
Knésl, Zden?k; Huta?, Pavel; Nezbedová, E.; Korbel, J.
Merseburg : Polymer service GmbH, 2009, s. 215-222. ISBN 978-3-86829-170-4. [Tagung problemseminar /12./ : Deformation und Bruchverhalten von Kunststoffen. Merseburg (DE), 24.06.2009-26.06.2009] R&D Projects: GA ?R GA106/09/0279 Institutional research plan: CEZ:AV0Z20410507 Keywords : Multilayer pipes * K-calibration * linear elastic fracture mechanics Subject RIV: JL - Materials Fatigue, Friction Mechanics
Planar multilayer structure analysis: an educational approach
Scientific Electronic Library Online (English)
D.B., Ferreira; A.F., Tinoco Salazar; I., Bianchi; J.C. da S., Lacava.
2012-06-01
Full Text Available This paper discusses how symbolic computation combined with a circuit model can be used for analyzing planar multilayer structures, in a manner suitable for educational approach. Working in the Fourier domain, expressions for the transversal spectral Green’s functions are evaluated in compact, close [...] d form using the symbolic computation capability of the Mathematica package. Printed antennas were analyzed through the method of moments. Further validation was achieved with the IE3D and HFSS packages.
PROACTIVE NETWORK SECURITYAPPROACH FOR MULTILAYERED ARCHITECURE
Lalitha Kumari R; Priyanka M; Lizyflorance. C
2013-01-01
In order to fulfill the organization goals and objectives, multilayered network architecture and various heterogeneous server environments are used. As the network architectures are complex, there is an increased demand in information security. So each organization needs to provide sufficient network security for the known and the unknown attacks according to its goals, requirements and objectives. Highly skilled hacker’s everyday discovers the new threats in order to break the security bridg...
NEUTRON REFLECTIVITY STUDIES FROM A PLATINUM CARBON MULTILAYER
Harwood, N.; Messoloras, S.; R Stewart; Penfold, J; Ward, R
1988-01-01
The neutron reflectivity from 30 Pt/C bilayers on an Si substrate has been measured using the time-of-flight (TOF) technique. The thickness of the bilayers, the total thickness of the multilayer structure and the density of the carbon and platinum layers are determined. The influence on the reflectivity curve of different types of multilayer-substrate and air-multilayer interfaces are examined. The experimental data are fitted with a reflectivity curve calculated by using a smoothly varying d...
Multiperiodicity in plasmonic multilayers: General description and diversity of topologies
DEFF Research Database (Denmark)
Orlov, Alexey A.; Krylova, Anastasia K.
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 multiperiodicity up to its fourth order are investigated. We demonstrate that various topologies of multiple-sheet isofrequency and dispersion surfaces exist for such plasmonic multilayers, including a photonic realization of nontrivial isolated Dirac cones.
Thermal behaviour of polymeric Langmuir-Blodgett multilayers
Erdelen, C.; Laschewsky, André; Ringsdorf, H.; Schneider, J; Schuster, A
1989-01-01
Langmuir-Blodgett multilayers of hydrocarbon and fluorocarbon polymers with hydrophilic spacer, lipid-polyelectrolyte complexes and mesogenic polymers have been prepared. The thermal behaviour of the multilayers was studied by small angle X-ray scattering, IR and UV—visible spectroscopy. Good thermal stabilities were found for the various classes of polymers. In addition, for both complexed multilayers and mesogenic polymer films, reorientation processes were observed.
Theory of the acoustical properties of symmetric multilayer structures
Martin, B. G.
1989-09-01
A theoretical investigation has been made of the acoustical properties of symmetrical multilayer structures. Acoustic symmetric multilayers (ASMs) exhibit behavior analogous to that of optical symmetric multilayers. For a three-layer ASM, a range of effective acoustic impedances is possible merely by varying the thickness of the middle layer for a given frequency. This has the advantage that one can design an antireflection coating for virtually any substrate impedance. Some illustrative examples are given.
Power Control in Multi-Layer Cellular Networks
Davaslioglu, Kemal; Ayanoglu, Ender
2012-01-01
We investigate the possible performance gains of power control in multi-layer cellular systems where microcells and picocells are distributed within macrocells. Although multilayers in cellular networks help increase system capacity and coverage, and can reduce total energy consumption; they cause interference, reducing the performance of the network. Therefore, downlink transmit power levels of multi-layer hierarchical cellular networks need to be controlled in order to ful...
Shortest Path Discovery in the Multi-layered Social Network
Bródka, Piotr; Stawiak, Pawe?; Kazienko, Przemys?aw
2012-01-01
Multi-layered social networks consist of the fixed set of nodes linked by multiple connections. These connections may be derived from different types of user activities logged in the IT system. To calculate any structural measures for multi-layered networks this multitude of relations should be coped with in the parameterized way. Two separate algorithms for evaluation of shortest paths in the multi-layered social network are proposed in the paper. The first one is based on ...
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.
Performance of multilayer coated silicon pore optics
DEFF Research Database (Denmark)
Ackermann, M. D.; Collon, M. J.
2010-01-01
The requirements for the IXO (International X-ray Observatory) telescope are very challenging in respect of angular resolution and effective area. Within a clear aperture with 1.7 m > R > 0.25 m that is dictated by the spacecraft envelope, the optics technology must be developed to satisfy 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.
Physical Properties of PC-PMMA Multilayers
Rahman, Arifur; Baer, Eric; Chipara, Alin Cristian; Vajtai, Robert; Ajayan, Pullickel M.; Hinthorne, James; Elamin, Ibrahim; Chipara, Mircea; Eric Baer Collaboration; Pullickel Ajayan Collaboration; Mircea Chipara Collaboration
2015-03-01
Multilayers of polycarbonate (PC) and polymethylmethacrylate (PMMA) have been obtained by the layer multiplying coextrusion method. Each sample (1024 layers, of equal thickness, with individual thickness between 10 and 200 nm) has been investigated at room temperature by Wide Angle X-Ray Scattering (WAXS) using a Bruker Discovery 8 spectrometer (Cu K ? radiation), Raman spectroscopy (Bruker Senterra confocal Raman spectrometer operating at 785 nm), FTIR spectroscopy (Tensor 27 Bruker), and UV-Vis spectroscopy. Further details about the glass transition temperature in these samples have been obtained by Dynamical Mechanical Analysis, DMA, (TA Instruments Q800) at various frequencies in the range 1 to 100 Hz. Isothermal Differential Scanning Calorimetry, DSC, (TA Instruments Q200) was used to investigate the effect of the thickness of the polymeric film on the crystallization processes. Non-isothermal DSC measurements aimed at the identification and location of the main phase transitions (glass, crystallization, and melting) occurring in these multilayers. The effects of confinement on the phase transitions occurring in these multilayers are discussed in detail.
Evolutionary games on multilayer networks: a colloquium
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.
Heat Transfer in High Temperature Multilayer Insulation
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.
Quantum Spin Hall phase in multilayer graphene
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.
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.
Modeling of composite materials and multilayered structures
Energy Technology Data Exchange (ETDEWEB)
Touratier, M. [ENSAM, Paris (France). Laboratoire de Mecanique des Structures
1993-12-31
The aim of this paper is to present efficient tools for predicting mechanical properties of most of the usual composite materials, and the response to the loading for multilayered structures. The essence of these tools is such that they are especially appropriate to the design of composite constructions. Three types of composite materials have been considered: composite materials with a matrix reinforced by long parallel fibers; composite materials with a matrix reinforced by randomly distributed short fibers; and last, two-dimensional woven fabric composites. For all these composite materials homogenized elastic properties are given and some indications are provided for hygrothermal properties. Experimental techniques in statics and in dynamics by ultrasonic wave propagation have allowed us to validate the above homogenization models. In order to provide a complete set of tools for the composite designer, a multilayered, doubly curved shallow shell model has been designed. This model is based on a new type of kinematics which has a three-dimensional essence and allows us to take into account a proper transverse shear deformation distribution and avoid transverse shear correction factors. Finally, contact conditions at interfaces between layers of the laminate have been taken into account both for displacements and for transverse shear stresses, the latter satisfying the free boundary conditions upon the top and bottom surfaces of the multilayered structures. Thus this model allows for instance, analyzing interface stresses useful to the design of composite structures in order to prevent delamination. The analysis may use analytical and/or finite element computations.
Interface roughness in Mo/Si multilayers
International Nuclear Information System (INIS)
In this work we present a study of surface roughness development at the molybdenum-on-silicon and silicon-on-molybdenum interfaces in Mo/Si multilayers as employed in Extreme UV lithography. Thin Mo/Si multilayers, with layer thicknesses of 3-5 nm, were deposited using electron beam evaporation. The effect of ion treatment on the surface roughness was studied by X-ray reflectometry and transmission electron microscopy. Without ion treatment we observed build up of correlated roughness. The roughness development is shown here to depend strongly on the thickness of the crystalline Mo layer. Independent of the Mo ratio in a period, we show that a minimal amount of ion treatment is required to smoothen the multilayer roughness, which is also confirmed by EUV reflectivity measurements. At high ion energies the layers become smoother due to a larger ion penetration depth. The higher penetration depth is also shown to initiate additional interdiffusion and structural changes at buried interfaces
Guana, Heyuan; Huang, Chenze; Chen, Zhe; Jin, Yunxia; Yi, Kui; Shao, Jianda
2015-07-01
The multilayer ridge metal/multilayer-dielectric gratings (MMDGs) for pulse compressors show high efficiency, broad bandwidths, large fabrication tolerances and high laser-induced damage thresholds. The diffraction efficiency, bandwidth, and near-field distribution of the multilayer structure ridge MMDG are theoretically investigated. Simulation results show that the film structure of the grating ridge has a great influence on the bandwidth and near-field distribution. The maximum electric field is located in the high-index layer of the grating ridge with high -1st diffraction efficiency. As the thickness of the high-index layer decreases, the maximum electric field moves to the low-index layer of the grating ridge with. Base on the results, the sandwich ridge MMDG is an ideal pulse compression grating for chirped pulse amplification systems.
Detection of recurrent rectal carcinoma with computed tomography
International Nuclear Information System (INIS)
In patients with abdominoperineal resection CT is the only effective radiological method for demonstrating the recurrence of rectal carcinomas. Our series consists of 20 patients examined with CT (38 examinations) because of suspected recurrent rectal carcinoma. Three patients had no recurrence. 13 recurrences were definitely diagnosed. In 2 cases the possibility of an abscess was considered. One recurrent tumour was misdiagnosed as postoperative fibrosis and one as a uterine fibroid. (orig.)
Detection of recurrent rectal carcinoma with computed tomography
Energy Technology Data Exchange (ETDEWEB)
Myllylae, V.; Paeivaensalo, M.; Laitinen, S.; Maekaeraeinen, H.
1986-03-01
In patients with abdominoperineal resection CT is the only effective radiological method for demonstrating the recurrence of rectal carcinomas. Our series consists of 20 patients examined with CT (38 examinations) because of suspected recurrent rectal carcinoma. Three patients had no recurrence. 13 recurrences were definitely diagnosed. In 2 cases the possibility of an abscess was considered. One recurrent tumour was misdiagnosed as postoperative fibrosis and one as a uterine fibroid.
Multi-Periodicity Induces Prominent Optical Phenomena in Plasmonic Multilayers
DEFF Research Database (Denmark)
Orlov, Alexey A.; Krylova, A. K.
2014-01-01
We introduce multi-periodicity in plasmonic multilayers and develop a general theory for the description of their eigenwaves. We define the order of multi-periodicity as the number of different kinds of plasmonic interfaces present in the multilayer, and investigate the optical effects that arise as this order increases from one (simple periodic multilayers) to two (bi- periodic multilayers) and beyond. For example, we show the formation of additional photonic bands, multi-refringence of p -polarized light, Dirac and mixed states.
A degree centrality in multi-layered social network
Bródka, Piotr; Kazienko, Przemys?aw; Musia?, Katarzyna
2012-01-01
Multi-layered social networks reflect complex relationships existing in modern interconnected IT systems. In such a network each pair of nodes may be linked by many edges that correspond to different communication or collaboration user activities. Multi-layered degree centrality for multi-layered social networks is presented in the paper. Experimental studies were carried out on data collected from the real Web 2.0 site. The multi-layered social network extracted from this data consists of ten distinct layers and the network analysis was performed for different degree centralities measures.
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.
Ultra hydrophobicity of Polydimethylsiloxanes-Based Multilayered Thin Films
International Nuclear Information System (INIS)
The formation of polydimethylsiloxanes (PDMSs)-based layer-by-layer multilayer ultrathin films on charged surfaces prepared from water and phosphate buffer solutions has been investigated. The multilayer films prepared under these conditions showed different surface roughness. Nano scale islands and network structures were observed homogeneously on the multilayer film prepared from pure water solutions, which is attributing to the ultrahydrobic property of the multilayer film. The formation of nano scale islands and network structures was due to the aggregation of PDMS-based poly electrolytes in water. This work provides a facile approach for generating ultra hydrophobic thin films on any charged surfaces by PDMS poly electrolytes
The first example of multilayer films with thermochromic properties
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.
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
FEBRILE SEIZURE: RECURRENCE AND RISK FACTORS
Directory of Open Access Journals (Sweden)
A. TALEBIAN
2006-06-01
Full Text Available Background:Febrile Convulsion is the most common convulsive disorder in children,occurring in 2 to 4% of the pediatric population and recurring in 30-50% of cases. Considering the varying recurrence rates reported, thisstudy was conducted at the pediatric ward of the Shaheed BeheshtiGeneral Hospital, between 2000-2001 to determine the frequencyof recurrence and related risk factors in children presenting with theirfirst episode of febrile convulsionMaterials & Methods:A two–year cohort study was performed on 50 children presentingwith the first attack of febrile convulsion. Patient demographic dataincluding age, sex, type and duration of seizure, family history offebrile seizure or epilepsy and the interval between fever onset andoccurrence of seizure were recorded in questionnaires. Those patients,for whom prophylactic medication was not administered, werefollowed at three–month intervals for up to one year. Findings werestatistically analyzed using Fisher’s exact testResults:Recurrence was observed in twelve children (24% out of the fifty,being most common in patients aged less than one year (54.4%.Recurrence rates among children with a positive family history offebrile convulsion, presence of complex febrile seizure and positivefamily history of epilepsy were 42.1%, 42.8% and 25% respectively.From among those children with a “less than one hour” intervalbetween fever onset and occurrence of seizure, recurrence occurredin 43-7% of cases, while in those with a “more than one hourinterval”, 14.7% experienced recurrence.Conclusion:Recurrence rates are increased by certain factors including age-belowone year-, positive family history of febrile convulsion, and a “lessthan one hour” interval between time of fever onset and seizureoccurrence.
Cytogenetic Study in Couples with Recurrent Miscarriage
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Tarek A. Atia, **Salah E. Mourad*** Salem H
2007-03-01
Full Text Available 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 common cause. About 7% of couples with RM have one partner with balanced chromosomal rearrangement. Aim of the study: This study is a prospective study carried out to evaluate the incidence of chromosomal abnormalities in couples suffering recurrent miscarriage. Patient and methods: The present study included one hundred couples attending the antenatal clinic. They have been divided into two groups; the first, is a study group, included 50 couples with recurrent miscarriage. And the second, is a control group, included 50 couples with normal reproductive history. Conventional cytogenetic analysis was done for both groups. Result: We have found four cases (8% carrying chromosomal rearrangements (two reciprocal translocations, one Robertsonian translocation, and one with duplicated chromosome segment among RM group, and no cases of chromosomal rearrangement among those with normal reproductive history. Statistically, there was a significant association between recurrent miscarriage and chromosomal rearrangement. Conclusion: We have concluded that chromosome analysis is highly important to evaluate such cases with RM
CT findings in recurrent pyogenic cholangitis
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Jung, Seung Hye; Lim, Jae Hoon; Ko, Young Tae; Lee, Dong Ho [Kyung Hee University Hospital, Seoul (Korea, Republic of)
1991-07-15
Recurrent pyogenic cholangitis is characterized clinically by recurrent attacks of right upper abdominal pain, fever and jaundice, and pathologically by chronic inflammation of the bile ducts with or without pigment bile duct stones. We analyzed the CT findings of 33 cases with recurrent pyogenic cholangitis. Twenty-four cases were confirmed by operation, and 9 cases were diagnosed clinically and cholangiographically. The CT findings of recurrent pyogenic cholangitis were dilatation of the intrahepatic ducts (n = 30), dilatation of the extrahepatic ducts (n = 24) intrahepatic stones (n = 16), extrahepatic stones (n = 12), stricture of the bile ducts (n = 10), wall enhancement of the bile ducts (n = 8), gallstones (n = 8), segmental atrophy of the liver (n = 7), pneumobilia (n = 4), abscess (n = 3), and segmental enhancement (n = 1) of the liver. A CT is considered helpful when sectional imaging is needed, but sonographic findings are equivocal or not confirmative; space-occupying lesions complicated with recurrent pyogenic cholangitis: hepatic resection is planned; and imaging guidance is needed for complex drainage procedures.
CT findings in recurrent pyogenic cholangitis
International Nuclear Information System (INIS)
Recurrent pyogenic cholangitis is characterized clinically by recurrent attacks of right upper abdominal pain, fever and jaundice, and pathologically by chronic inflammation of the bile ducts with or without pigment bile duct stones. We analyzed the CT findings of 33 cases with recurrent pyogenic cholangitis. Twenty-four cases were confirmed by operation, and 9 cases were diagnosed clinically and cholangiographically. The CT findings of recurrent pyogenic cholangitis were dilatation of the intrahepatic ducts (n = 30), dilatation of the extrahepatic ducts (n = 24) intrahepatic stones (n = 16), extrahepatic stones (n = 12), stricture of the bile ducts (n = 10), wall enhancement of the bile ducts (n = 8), gallstones (n = 8), segmental atrophy of the liver (n = 7), pneumobilia (n = 4), abscess (n = 3), and segmental enhancement (n = 1) of the liver. A CT is considered helpful when sectional imaging is needed, but sonographic findings are equivocal or not confirmative; space-occupying lesions complicated with recurrent pyogenic cholangitis: hepatic resection is planned; and imaging guidance is needed for complex drainage procedures
2015-07-22
Estrogen Receptor Negative; HER2/Neu Negative; Ovarian Endometrioid Adenocarcinoma; Ovarian Serous Cystadenocarcinoma; Ovarian Serous Surface Papillary Adenocarcinoma; Progesterone Receptor Negative; Recurrent Breast Carcinoma; Recurrent Fallopian Tube Carcinoma; Recurrent Ovarian Carcinoma; Recurrent Primary Peritoneal Carcinoma; Triple-Negative Breast Carcinoma
RECURRENT SUBCLITORAL ABSCESS TREATED BY MARSUPIALIZATION
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HORMOZ DABIRASHRAFI
1986-05-01
Full Text Available This is a report of a very rare case of recurrent subclitoral abscess. Its etiology and the best treatment of the disease is here in discussed. We, the same as Sur, believe that marsupialization is the most promising treatment. Recurrent periclitoral abscess has been described previously5. s ome of the authors believe that it is part of the pilonidal disease. The first pilonidal cyst in 7 the clitoral region was introduced by Palmer (1957."nAnother case of pilonidal sinus of clitoris was repor-2 ted by Betson . All of the researchers are not in this opinion that the disease is necessarily a pilonidal sinus 1 3,and, sometimes, there is not any hair in the epithelium lining of the cyst. One case of recurrent subclitoral abscess treated by marsupialization is presented here.
Sickle cell disease with recurrent priapism.
Khot, Rajashree; Aher, Archana
2012-11-01
Sickle cell disease is a very common entity in central India, especially in Maharashtra. Patients usually present with recurrent haemolytic and/or vaso-occlusive crises. Although unusual, Priapism i.e. spontaneous painful erection of penis can be a debilitating manifestation of crisis. Especially when it occurs in prepubertal males it can lead to impotence in later life. It is also one of the least discussed complications of sickle cell disease. Here we present a case of sickle cell disease with recurrent priapism in a young boy of 16 years of age. He failed to respond to standard line of treatment. When all modalities failed he was given Tablet Gabapentin after which his priapism was totally relieved. We would like to recommend the use of Gabapentin in such cases of recurrent priapism. PMID:23767208
Fetal gender ratio in recurrent miscarriages
Del Fabro, Anna; Driul, Lorenza; Anis, Omar; Londero, Ambrogio P; Bertozzi, Serena; Bortotto, Livio; Marchesoni, Diego
2011-01-01
Background: The purpose of this study was to evaluate the gender ratio and incidence of chromosomal anomalies in the products of conception (POC) from recurrent miscarriages. Methods: We determined the karyotypes of POC from patients with recurrent spontaneous miscarriages between 1999 and 2009. Results: In total, 313 specimens were successfully karyotyped, with a median gestational age of 10 weeks at miscarriage (interquartile range 8–13); 199 (64%) were females and 114 (36%) were males. In total, 121 (39%) had abnormal karyotypes, the most prevalent of which were chromosome 21 and 16 trisomies, triploidy, and monosomy X. Conclusion: Our findings suggest that female POC might be more susceptible to recurrent miscarriages than male ones during embryogenesis, implantation, and initial fetal development. PMID:21845066
Hausdorff Dimension of Measuresvia Poincaré Recurrence
Barreira, L.; Saussol, B.
We study the quantitative behavior of Poincaré recurrence. In particular, for an equilibrium measure on a locally maximal hyperbolic set of a C1+? diffeomorphism f, we show that the recurrence rate to each point coincides almost everywhere with the Hausdorff dimension d of the measure, that is, inf{k>0 :fkx?B(x,r)} r-d. This result is a non-trivial generalization of work of Boshernitzan concerning the quantitative behavior of recurrence, and is a dimensional version of work of Ornstein and Weiss for the entropy. We stress that our approach uses different techniques. Furthermore, our results motivate the introduction of a new method to compute the Hausdorff dimension of measures.
Recurrence quantification analysis of global stock markets
Bastos, João A.; Caiado, Jorge
2011-04-01
This study investigates the presence of deterministic dependencies in international stock markets using recurrence plots and recurrence quantification analysis (RQA). The results are based on a large set of free float-adjusted market capitalization stock indices, covering a period of 15 years. The statistical tests suggest that the dynamics of stock prices in emerging markets is characterized by higher values of RQA measures when compared to their developed counterparts. The behavior of stock markets during critical financial events, such as the burst of the technology bubble, the Asian currency crisis, and the recent subprime mortgage crisis, is analyzed by performing RQA in sliding windows. It is shown that during these events stock markets exhibit a distinctive behavior that is characterized by temporary decreases in the fraction of recurrence points contained in diagonal and vertical structures.
Recurrent intramedullary epidermoid cyst of conus medullaris.
LENUS (Irish Health Repository)
Fleming, Christina
2011-01-01
Spinal intramedullary epidermoid cyst is a rare condition. Recurrent epidermoid cyst in the spine cord is known to occur. The authors describe a case of recurrent conus medullaris epidermoid cyst in a 24-year-old female. She initially presented at 7 years of age with bladder disturbance in the form of diurnal enuresis and recurrent urinary tract infection. MRI lumbar spine revealed a 4 cm conus medullaris epidermoid cyst. Since the initial presentation, the cyst had recurred seven times in the same location and she underwent surgical intervention in the form of exploration and debulking. This benign condition, owing to its anatomical location, has posed a surgical and overall management challenge. This occurrence is better managed in a tertiary-care centre requiring multi-disciplinary treatment approach.
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...
Recurrent benign myoepithelioma of the auricle.
Oh, Se-Joon; Kong, Soo-Keun; Lee, Il-Woo; Goh, Eui-Kyung
2014-12-01
Myoepithelioma, a generally benign tumor comprised of myoepithlial cells, is an uncommon salivary gland tumor. Myoepithelioma originates primarily in the parotid gland, but several isolated cases have been described. Although myoepithelioma has a benign nature, but there is a potential risk of malignant change and recurrence in case of incomplete resection. We acknowledge that benign myoepithelioma originating from the auricle has not been reported in the English literature. We present a rare case of 27-year-old female who had recurrent benign myoepithelioma originating from the auricle and already had been given twice operations at the other clinic. PMID:25558409
Comment on "Recurrences without closed orbits"
Main, J
1999-01-01
In a recent paper Robicheaux and Shaw [Phys. Rev. A 58, 1043 (1998)] calculate the recurrence spectra of atoms in electric fields with non-vanishing angular momentum not equal to 0. Features are observed at scaled actions ``an order of magnitude shorter than for any classical closed orbit of this system.'' We investigate the transition from zero to nonzero angular momentum and demonstrate the existence of short closed orbits with L_z not equal to 0. The real and complex ``ghost'' orbits are created in bifurcations of the ``uphill'' and ``downhill'' orbit along the electric field axis, and can serve to interpret the observed features in the quantum recurrence spectra.
RECURRENT SUBCLITORAL ABSCESS TREATED BY MARSUPIALIZATION
HORMOZ DABIRASHRAFI; SIMIN KAMYAB TEHRANY
1986-01-01
This is a report of a very rare case of recurrent subclitoral abscess. Its etiology and the best treatment of the disease is here in discussed. We, the same as Sur, believe that marsupialization is the most promising treatment. Recurrent periclitoral abscess has been described previously5. s ome of the authors believe that it is part of the pilonidal disease. The first pilonidal cyst in 7 the clitoral region was introduced by Palmer (1957)."nAnother case of pilonidal sinus of clitoris wa...
Optimizing of recurrence plots for noise reduction.
Matassini, Lorenzo; Kantz, Holger; Ho?yst, Janusz; Hegger, Rainer
2002-02-01
We propose a way to automatically detect the best neighborhood size for a local projective noise reduction filter, where a typical problem is the proper identification of the noise level. Here we make use of concepts from the recurrence quantification analysis in order to adaptively tune the filter along the incoming time series. We define an index, to be computed via recurrence plots, whose minimum gives a clear indication of the best size of the neighborhood in the embedding space. Comparison of the local projective noise reduction filter using this optimization scheme with the state of the art is also provided. PMID:11863498
Mining Recurrent Pattern Identification on Large Database
Shivangi Srivastava; Ganesh Khadanga; Divya Gupta
2014-01-01
Recurrent pattern mining is an important problem in the context of data mining. In this paper data mining algorithms have been discussed and compared. Recurrent pattern mining has been an important area in data mining research and it is the first step in the analysis of data rising in a broad range of applications. The algorithms are compared with respect to the items like methodology and its basic principles in terms of the elements user like support, and scan of the database (full or parti...
Mining Recurrent Pattern Identification on Large Database
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Shivangi Srivastava
2014-04-01
Full Text Available Recurrent pattern mining is an important problem in the context of data mining. In this paper data mining algorithms have been discussed and compared. Recurrent pattern mining has been an important area in data mining research and it is the first step in the analysis of data rising in a broad range of applications. The algorithms are compared with respect to the items like methodology and its basic principles in terms of the elements user like support, and scan of the database (full or partial.
Characterization of normal-incidence water-window multilayer optics
International Nuclear Information System (INIS)
Spherical normal-incidence multilayer mirrors are attractive alternatives as condensers in compact water-window x-ray microscopes. In this paper we discuss the properties of such multilayer mirrors and the requirements when they are combined with a line-emitting soft x-ray source
MAGNETIZATION PROCESS OF Gd/Co MULTILAYER FILMS
Tsunashima, S.; Ichikawa, T; Nawate, M.; UCHIYAMA, S
1988-01-01
Gd/Co multilayer films were prepared by electron beam evaporation in a vacuum of ~ 10-7 Torr. The multilayer film of (110 Å Gd/147 Å Co) x 12 showed peculiar magnetization process around 150 K. This can be attributed to a transition of Gd spins from aligned to twisted states.
Tactile display with dielectric multilayer elastomer actuatorsq
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.
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 theoreollows from the Lorentz reciprocity theorem. Thus, in this case the formalism of Green's functions is not needed
MULTI-LAYER GRID REFINEMENT METHOD
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TSUN-ZEE MAI
2012-07-01
Full Text Available The uniform grid scheme has been widely used to solve a partial differential equation. Due to the extreme large linear systems generated by the uniform grid scheme, a lot of computation time is required. To improve the efficiency of the uniform grid scheme, a more economical method is desirable. In this paper, we propose a multi-layer grid refinement method for solving a partial different equation over a rectangular domain with Dirichlet boundary conditions. Numerical experiments demonstrate that the efficiency has been improved significantly, and the accuracy is satisfactory.
Digital biomagnetism: Electrodeposited multilayer magnetic barcodes
International Nuclear Information System (INIS)
A novel magnetic encoding technique for performing high-throughput biological assays is presented. Electrodeposited Ni/Cu and Co/Cu multilayer pillar structures with a diameter of 15 ?m and a thickness up to 10 ?m are presented as 'magnetic barcodes', where the number of unique codes possible increases exponentially with a linear increase in length. A gold cap facilitates the growth of self-assembled monolayers (SAMs), while microdrop printing allows efficient generation of large libraries of tagged probes. Coercivity-tuning techniques are used to exploit a non-proximity encoding methodology compatible with microfluidic flow.
Spin wave spectra in metamagnet multilayers
Energy Technology Data Exchange (ETDEWEB)
Souza, J.M. de; Albuquerque, E.L.; Anselmo, D.H.A.L.; Farias, G.A
2002-12-01
A microscopic theory is employed to investigate the spin wave spectra in binary multilayer structures, where one of their components is a metamagnetic material, the other one being a simple cubic ferromagnetic crystal. The metamagnet consists of ferromagnetically ordered layers, with the intralayer ferromagnetic exchange interactions being much stronger than the weak antiferromagnetic interaction between adjacent layers. The calculations are carried out for the exchange-dominated regime within the framework of the Heisenberg model and taking into account the random phase approximation. For numerical calculations, we consider as the metamagnet material the well-known FeCl{sub 2} and FeBr{sub 2}, Fe being the ferromagnet spacer.
Spin wave spectra in metamagnet multilayers
International Nuclear Information System (INIS)
A microscopic theory is employed to investigate the spin wave spectra in binary multilayer structures, where one of their components is a metamagnetic material, the other one being a simple cubic ferromagnetic crystal. The metamagnet consists of ferromagnetically ordered layers, with the intralayer ferromagnetic exchange interactions being much stronger than the weak antiferromagnetic interaction between adjacent layers. The calculations are carried out for the exchange-dominated regime within the framework of the Heisenberg model and taking into account the random phase approximation. For numerical calculations, we consider as the metamagnet material the well-known FeCl2 and FeBr2, Fe being the ferromagnet spacer
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.
Magnetoelectronic properties of multilayer black phosphorus
Jiang, Yongjin; Roldán, Rafael; Guinea, Francisco; Low, Tony
2015-08-01
We examine the electronic properties of two-dimensional electron gas in black phosphorus multilayers in the presence of a perpendicular magnetic field, highlighting the role of in-plane anisotropy on various experimental quantities such as ac magnetoconductivity, screening, and magnetoplasmons. We find that resonant structures in the ac conductivity exhibits a redshift with increasing doping due to interband coupling ? . This arises from an extra correction term in the Landau energy spectrum proportional to n2?2 (n is Landau index), up to second order in ? . We found also that Coulomb interaction leads to highly anisotropic magnetoexcitons.
Plasmonic waveguides with hyperbolic multilayer cladding
Babicheva, Viktoriia E; Ishii, Satoshi; Boltasseva, Alexandra; Kildishev, Alexander V
2014-01-01
Engineering plasmonic metamaterials with anisotropic optical dispersion enables us to tailor the properties of metamaterial-based waveguides. We investigate plasmonic waveguides with dielectric cores and multilayer metal-dielectric claddings with hyperbolic dispersion. Without using any homogenization, we calculate the resonant eigenmodes of the finite-width cladding layers, and find agreement with the resonant features in the dispersion of the cladded waveguides. We show that at the resonant widths, the propagating modes of the waveguides are coupled to the cladding eigenmodes and hence, are strongly absorbed. By avoiding the resonant widths in the design of the actual waveguides, the strong absorption can be eliminated.
Optical nutation in multilayered ellipsoidal quantum dots
Sadeghi, E.
2015-09-01
The optical nutation signal of two and three ellipsoidal quantum dots (EQD) with finite confinement potential in the presence of polarized laser field is considered. In this regard, the effective-mass approximation within a perturbation scheme is used and the induced effective polarization of atoms in the multilayered ellipsoidal quantum dots is calculated for GaAs/GaAlAs/GaAs structure. The results showed that the optical nutation peak depends not only on the thickness of the intermediate layer but also on the ellipticity constant.
Supervised Learning in Multilayer Spiking Neural Networks
Sporea, Ioana
2012-01-01
The current article introduces a supervised learning algorithm for multilayer spiking neural networks. The algorithm presented here overcomes some limitations of existing learning algorithms as it can be applied to neurons firing multiple spikes and it can in principle be applied to any linearisable neuron model. The algorithm is applied successfully to various benchmarks, such as the XOR problem and the Iris data set, as well as complex classifications problems. The simulations also show the flexibility of this supervised learning algorithm which permits different encodings of the spike timing patterns, including precise spike trains encoding.
A polyoxometalate-cyanometalate multilayered coordination network.
Compain, Jean-Daniel; Nakabayashi, Koji; Ohkoshi, Shin-ichi
2012-05-01
The reaction of the ?-Keggin polyoxometalate (POM) [PMo(12)O(36)(OH)(4){La(H(2)O)(4)}(4)](5+) with Fe(II)(CN)(6)(4-) under typical bench conditions at room temperature and ambient pressure has afforded the novel [?-PMo(12)O(37)(OH)(3){La(H(2)O)(5)(Fe(CN)(6))(0.25)}(4)] network, which exhibits a three-dimensional multilayered structure. The compound has been fully characterized by synchrotron-radiation X-ray crystallography, IR spectroscopy, elemental analysis, and thermogravimetric analysis. This coordination network constitutes the first example of a cyanometalate bonded to a POM unit. PMID:22506558
Multimedia Traffic Routing in Multilayer WDM Networks
Amphawan, Angela; Hasan, Hassanuddin
2012-01-01
The advent of real-time multimedia services over the Internet has stimulated new technologies for expanding the information carrying capacity of optical network backbones. Multilayer wavelength division multiplexing (WDM) packet switching is an emerging technology for increasing the bandwidth of optical networks. Two algorithms for the routing of the multimedia traffic flows were applied: (i) Capacitated Shortest Path First (CSPF) routing, which minimizes the distance of each flow linking the given source and destination nodes and satisfying capacity constraints; and (ii) Flow Deviation Algorithm (FDA) routing, which minimizes the network?wide average packet delay.
Power Control in Multi-Layer Cellular Networks
Davaslioglu, Kemal
2012-01-01
We investigate the possible performance gains of power control in multi-layer cellular systems where microcells and picocells are distributed within macrocells. Although multilayers in cellular networks help increase system capacity and coverage, and can reduce total energy consumption; they cause interference, reducing the performance of the network. Therefore, downlink transmit power levels of multi-layer hierarchical cellular networks need to be controlled in order to fully exploit their benefits. In this work, we present an analytical derivation to determine optimum power levels for two-layer cellular networks and generalize our solution to multi-layer cellular networks. We also simulate our results in a typical multi-layer network setup and observe significant power savings compared to single-layer cellular networks.
Tc vs n relationship for multilayered high-Tc superconductors
International Nuclear Information System (INIS)
We have proposed a Tc vs n relationship for multilayered high-Tc superconductors from the analysis of HgBa2Can-1CunOy grain-aligned samples containing n=6 to 16 phases. The sample showed a large and sharp superconducting transition at 105 K in its susceptibility vs temperature curve. This means that multilayered HgBa2Can-1CunOy can maintain a high Tc at least up to n approx. = 16, otherwise many transitions would have been observed. It is generally believed that the highest Tc decreases with n for n?4-5 for multilayered superconductors. We conclude that the highest Tc is almost constant above about n=5 if the factors reducing Tc, such as disorder, are eliminated for multilayered superconductors. This behavior can be explained using an inhomogeneous charge distribution model in multilayered cuprates. (author)
Clustering Network Layers With the Strata Multilayer Stochastic Block Model
Stanley, Natalie; Taylor, Dane; Mucha, Peter J
2015-01-01
Multilayer networks are a useful data structure for simultaneously capturing multiple types of relationships between a set of nodes. In such networks, each relational definition gives rise to a layer. While each layer provides its own set of information, community structure can be collectively utilized to discover and quantify underlying relational patterns. To most concisely extract information from a multilayer network, we propose to identify and combine sets of layers with meaningful similarities in community structure. In this paper, we describe the strata multilayer stochastic block model (sMLSBM), a probabilistic model for multilayer community structure. The assumption of the model is that there exist groups of layers, that we call strata, with community structure described by a common stochastic block model (SBM). That is, layers in a stratum exhibit similar node-to-community assignments as well as SBM probability parameters. Fitting the sMLSBM to a multilayer network provides a joint clustering of nod...
An X-ray grazing incidence phase multilayer grating
International Nuclear Information System (INIS)
An X-ray grazing incidence phase multilayer grating, representing a thin grating placed on a multilayer mirror, is proposed. A high efficiency of grating diffraction can be obtained by the possibility of changing the phase shift of the wave diffracted from the multilayer under the Bragg and total external reflection conditions. A grazing incidence phase multilayer grating consisting of Pt grating stripes on a Ni/C multilayer and optimized for the hard X-ray range was fabricated. Its diffraction properties were studied at photon energies of 7 and 8 keV. The obtained maximum value of the diffraction efficiency of the +1 grating order was 9% at 7 keV and 6.5% at 8 keV. The data obtained are in a rather good accordance with the theory
Fabrication, measurement, and analysis of multilayer x- ray diffraction gratings
Hansen, Douglas P.
1997-12-01
I examine the theory and fabrication of lamellar multilayer x-ray diffraction gratings. I use current theory based on the Kirchoff Integral for amplitude gratings and a new equation for phase gratings to analyze current technology multilayer grating performance (where the period/? exceeds 10). I examine the possible fabrication methods and define two general categories (additive: multilayer added to patterned substrate, subtractive: grating etched into multilayer). I conclude the additive approach is superior, leading to x-ray analogues to binary optics and holographic optical elements. I define an additive process in detail and demonstrate the serviceability of the key processes: thermal growth of silicon dioxide on silicon, lithography, a combined plasma-etch and wet-etch. Multilayer fabrication difficulties on patterned substrates are identified, including: mushroom cap growth, and filleting in the grooves. Measurements done at NSLS on 2 amplitude gratings and 1 phase grating are reported. The data is shown to be compatible with the Kirchoff theory.
An X-ray grazing incidence phase multilayer grating
Chernov, V A; Mytnichenko, S V
2001-01-01
An X-ray grazing incidence phase multilayer grating, representing a thin grating placed on a multilayer mirror, is proposed. A high efficiency of grating diffraction can be obtained by the possibility of changing the phase shift of the wave diffracted from the multilayer under the Bragg and total external reflection conditions. A grazing incidence phase multilayer grating consisting of Pt grating stripes on a Ni/C multilayer and optimized for the hard X-ray range was fabricated. Its diffraction properties were studied at photon energies of 7 and 8 keV. The obtained maximum value of the diffraction efficiency of the +1 grating order was 9% at 7 keV and 6.5% at 8 keV. The data obtained are in a rather good accordance with the theory.
Magnetisation reversal in anisotropy graded Co/Pd multilayers
Barton, C. W.; Thomson, T.
2015-08-01
We demonstrate high precision controllability of the magnetization reversal nucleation process in [Co/Pd]8 multilayer films consisting of two sets of bilayers with high and low perpendicular anisotropy, respectively. The anisotropy of the entire film is set by the degree of Co/Pd interfacial mixing during deposition which provides fine control of the anisotropy of an individual bilayer in the multilayer stack. The relative number of each type of bilayer is used to select the magnetisation reversal behavior such that changing one bilayer changes the properties of the entire multilayer through anisotropy averaging. A simple extension to the sputtering protocol would provide multilayer films with fully graded anisotropy, while maintaining a constant saturation magnetization opening new possibilities for the creation of highly engineered multilayer structures for spin torque devices and future magnetic recording media.
Co/Mg/X Multilayer Mirrors For the EUV Range
International Nuclear Information System (INIS)
A new material combination namely Co/Mg multilayer designed for optics applications in the EUV range, is reported. Simulations show that reflectivity value of the Co/Mg multilayer can reach a reflectivity of 55% at 25.2 nm (49.2 eV), when the grazing incidence angle is set to 45 deg. and s polarization is considered. The introduction of additional materials, e.g., Y and Zr can improve the reflectivity to 61%. Co/Mg and Co/Mg/B4C multilayers have been deposited following the parameters deduced from the simulations. The introduction of a B4C barrier layer would in principle increase the multilayer reflectivity to 61%. In fact the reflectivity measurements at 0.154 nm show that the introduction of B4C does not improve the structural quality of the multilayers.
Chen, Wei-Shing
2011-04-01
The aim of the article is to answer the question if the Taiwan unemployment rate dynamics is generated by a non-linear deterministic dynamic process. This paper applies a recurrence plot and recurrence quantification approach based on the analysis of non-stationary hidden transition patterns of the unemployment rate of Taiwan. The case study uses the time series data of the Taiwan’s unemployment rate during the period from 1978/01 to 2010/06. The results show that recurrence techniques are able to identify various phases in the evolution of unemployment transition in Taiwan.
Endoluminal brachytherapy for recurrent laryngeal carcinoma.
Latham, M M; Smart, G P; Hedland-Thomas, B; Harper, C S
1997-11-01
Early-stage squamous cell carcinoma of the larynx is usually treated with local field radiotherapy. Surgery is used for salvage following recurrence. Further recurrences present a more difficult therapeutic problem which requires individualized management. The aims of local control, survival, maintenance of function and minimizing side effects all need to be balanced according to the site and extent of disease. The present case study looks at the management of a 54-year-old man with multiple recurrences from a squamous cell carcinoma of the larynx. It describes a technique of endoluminal brachytherapy using an iridium-192 wire spiralled around the outer part of a tracheostomy tube that achieves good local control while enabling self-insertion and self-cleaning during the procedure. The dose given was 2500 cGy at 5 mm over 25.2 h and was achieved with minimal early or delayed side effects. The patient had no further symptoms relating to the stomal recurrence until his death from metastatic disease 6 months later. PMID:9409028
Chemoprophylaxis in the vesical tumoral recurrence
International Nuclear Information System (INIS)
The superficial bladder tumors are characterized by a high rate of recurrence taking place especially within the first two years that is even higher in the high risk groups. There is an agreement in the usefulness of the Calmette-Guerin Bacillus (CGB) to diminish the tumoral recurrence. The intravesical chemotherapy with other medications have demonstrated its profit or not in decreasing the recurrence of these bladder tumors. Between 1999 and 2008 we studied and treated 110 patients (96 men and 14 women), aged in average 63 years old. They were divided into three groups for the treatment of the tumoral recidivism after the transurethral resection or partial cystectomy, using three different chemoprophylactic agents and inmunomodulators (Thio-Tepa, BCG+Transference Factor, Doxorubicin +Interferon Alpha 2b). The objective of this research was presenting our experience in the treatment of these patients during five years, obtaining better results in the group treated with doxorubicin + interferon alpha 2b, followed by the group treated by means of BCG + transference factor, with a remarked decrease of the recurrence and a limitation in the long term progression of the disease
Periodic and recurrent variations of cosmic rays
International Nuclear Information System (INIS)
The new results achieved in the field of periodic and recurrent variations of the intensity of 109 to 1013 eV cosmic rays are reviewed. Particular emphasis is given to developments in understanding the fluctuations of corotation-type anisotropies as well as to the structure of the heliosphere and its temporal changes. (author)
Recurrent furunculosis – challenges and management: a review
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Ibler KS
2014-02-01
Full Text Available Kristina Sophie Ibler, Charles B Kromann Department of Dermatology, Roskilde Hospital, Copenhagen University, Denmark Abstract: Furunculosis is a deep infection of the hair follicle leading to abscess formation with accumulation of pus and necrotic tissue. Furuncles appear as red, swollen, and tender nodules on hair-bearing parts of the body, and the most common infectious agent is Staphylococcus aureus, but other bacteria may also be causative. In some countries, methicillin resistant S. aureus is the most common pathogen in skin and soft tissue infections which is problematic since treatment is difficult. Furunculosis often tends to be recurrent and may spread among family members. Some patients are carriers of S. aureus and eradication should be considered in recurrent cases. Solitary lesions should be incised when fluctuant, whereas patients with multiple lesions or signs of systemic disease or immunosuppression should be treated with relevant antibiotics. The diagnostic and therapeutic approach to a patient suspected of staphylococcosis should include a thorough medical history, clinical examination, and specific microbiological and biochemical investigations. This is particularly important in recurrent cases where culture swabs from the patient, family members, and close contacts are mandatory to identify and ultimately control the chain of infection. Focus on personal, interpersonal, and environmental hygiene issues is crucial to reduce the risk of contamination and recurrences. Keywords: furunculosis, MRSA, SSTI, boils, abscess, staphylococcosis
Surgical Management of Recurrent Nasopharyngeal Carcinoma
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Sheng-Po Hao
2010-08-01
Full Text Available 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 access the nasopharynx. Through amultidisciplinary approach with the collaboration of neurosurgeons,the surgical indication of salvage surgery is extended.This allowed improved respectability in locally advanced diseaseand involved the skull base and intracranial extensionwith reasonable morbidity and mortality. Endoscopic nasopharyngectomyis a choice for recurrent NPC with central roof orfloor lesions with minimal lateral extension. Multivariate analysis indicated that gender,parapharyngeal space involvement, surgical margin, and the modality of adjuvant therapyimpact significantly on local control. The impact on survival is indicated by the dura orbrain involvement, local recurrence and modality of adjuvant therapy. It is apparent thatrecurrent NPC patients who underwent surgery had a significantly better survival rate thanthe re-radiation therapy group.
Fetal gender ratio in recurrent miscarriages
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Del Fabro A
2011-07-01
Full Text Available Anna Del Fabro1, Lorenza Driul1, Omar Anis1, Ambrogio P Londero1, Serena Bertozzi2, Livio Bortotto3, Diego Marchesoni11Clinic of Obstetrics and Gynecology, 2Clinic of Surgery, 3Unit of Genetics, University Hospital of Udine, Udine, ItalyBackground: The purpose of this study was to evaluate the gender ratio and incidence of chromosomal anomalies in the products of conception (POC from recurrent miscarriages.Methods: We determined the karyotypes of POC from patients with recurrent spontaneous miscarriages between 1999 and 2009.Results: In total, 313 specimens were successfully karyotyped, with a median gestational age of 10 weeks at miscarriage (interquartile range 8–13; 199 (64% were females and 114 (36% were males. In total, 121 (39% had abnormal karyotypes, the most prevalent of which were chromosome 21 and 16 trisomies, triploidy, and monosomy X.Conclusion: Our findings suggest that female POC might be more susceptible to recurrent miscarriages than male ones during embryogenesis, implantation, and initial fetal development.Keywords: fetal gender, recurrent miscarriages, karyotype anomalies
Recurrent Catamenial Pneumothorax Suggestive of Pleural Endometriosis
Badawy, Shawky Z. A.; Pujan Shrestha
2014-01-01
A 42-year-old multiparous patient presented for consultation as a referral for management of recurrent catamenial pneumothorax. Evaluation by a pulmonologist failed to reveal any chest masses. She was treated for endometriosis using Danazol 800?mg daily for 6 months. Pneumothorax did not recur during treatment and during follow-up visits.
Recurrent Sepsis Caused by Streptococcus pyogenes?
Rasmussen, Magnus
2011-01-01
I report that a 75-year-old man with severe atherosclerosis experienced two episodes of bacteremia with Streptococcus pyogenes of type emm87. Recurrent sepsis with S. pyogenes is extremely rare, and a foot ulcer was the suspected point of entry. The patient did not develop opsonizing antibodies to the isolate.
Recurrent focal segmental glomerulosclerosis after kidney transplantation.
Trachtman, Rebecca; Sran, Simranjeet S; Trachtman, Howard
2015-10-01
Focal segmental glomerulosclerosis (FSGS) is an important cause of glomerular disease in children and adolescents and nearly 50 % of affected patients will progress to end-stage kidney disease over a 5 to 10-year period. Unfortunately, there is no established treatment for disease in the native kidney. Moreover, up to 55 % of patients develop recurrent disease after receiving a kidney transplant, with a substantially higher risk in patients who have already experienced recurrent disease in a prior transplant. A number of clinical and laboratory factors have been identified as risk factors for this complication. In addition, new investigations into podocyte biology and circulating permeability factors have shed light on the cause of recurrent the disease. While a number of novel therapeutic agents have been applied in the management of this problem, there still is no proven treatment. In this review, we summarize recent advances in the epidemiology, pathophysiology, and treatment of recurrent FSGS in pediatric patients who have received a kidney transplant. PMID:25690943
Recurrent Intestinal Obstruction Caused by Abdominal Cocoon
Rohit Bansal; Singh, D.P.
2014-01-01
Abdominal cocoon is a rare disease of the peritoneum and the rare cause of intestinal obstruction. The etiology of this disease is largely unknown. It primarily affects young adolescent females. We report a case of abdominal cocoon in a 16-year-old girl patient who presented with recurrent episodes of subacute intestinal obstruction.
ConcepTest: EQ Recurrence Interval
Plate A moves 3 cm/yr past plate B. A typical earthquake along the plate boundary has 6 meters of slip. What is the recurrence interval of the earthquake? a. 0.2 years b. 2 years c. 200 years d. 2000 years
Recurrence quantification analysis in Liu's attractor
International Nuclear Information System (INIS)
Recurrence Quantification Analysis is used to detect transitions chaos to periodical states or chaos to chaos in a new dynamical system proposed by Liu et al. This system contains a control parameter in the second equation and was originally introduced to investigate the forming mechanism of the compound structure of the chaotic attractor which exists when the control parameter is zero
Otobasal liquor fistula causing recurrent bacterial meningitis
International Nuclear Information System (INIS)
Cerebral subarachnoid space scintigraphy today still is the modality of choice for detection of a liquorrea or a liquor fistula, especially in the case of a recurrent menengitis of unclear origin. This diagnostic method yielded the results required in the case reported for efficient and successful surgical treatment. (orig./CB)
Epidemic model with isolation in multilayer networks
Zuzek, L G Alvarez; Braunstein, L A
2014-01-01
The Susceptible-Infected-Recovered (SIR) model has successfully mimicked the propagation of such airborne diseases as influenza A (H1N1). Although the SIR model has recently been studied in a multilayer networks configuration, in almost all the research the dynamic movement of infected individuals, e.g., how they are often kept in isolation, is disregarded. We study the SIR model in two multilayer networks and use an isolation parameter, indicating time period, to measure the effect of isolating infected individuals from both layers. This isolation reduces the transmission of the disease because the time in which infection can spread is reduced. In this scenario we find that the epidemic threshold increases with the isolation time and the isolation parameter and the impact of the propagation is reduced. We also find that when isolation is total there is a threshold for the isolation parameter above which the disease never becomes an epidemic. We also find that regular epidemic models always overestimate the e...
Polymer multilayer tattooing for enhanced DNA vaccination
Demuth, Peter C.; Min, Younjin; Huang, Bonnie; Kramer, Joshua A.; Miller, Andrew D.; Barouch, Dan H.; Hammond, Paula T.; Irvine, Darrell J.
2013-04-01
DNA vaccines have many potential benefits but have failed to generate robust immune responses in humans. Recently, methods such as in vivo electroporation have demonstrated improved performance, but an optimal strategy for safe, reproducible, and pain-free DNA vaccination remains elusive. Here we report an approach for rapid implantation of vaccine-loaded polymer films carrying DNA, immune-stimulatory RNA, and biodegradable polycations into the immune-cell-rich epidermis, using microneedles coated with releasable polyelectrolyte multilayers. Films transferred into the skin following brief microneedle application promoted local transfection and controlled the persistence of DNA and adjuvants in the skin from days to weeks, with kinetics determined by the film composition. These ‘multilayer tattoo’ DNA vaccines induced immune responses against a model HIV antigen comparable to electroporation in mice, enhanced memory T-cell generation, and elicited 140-fold higher gene expression in non-human primate skin than intradermal DNA injection, indicating the potential of this strategy for enhancing DNA vaccination.
Finite element analysis of multilayer coextrusion.
Energy Technology Data Exchange (ETDEWEB)
Hopkins, Matthew Morgan; Schunk, Peter Randall; Baer, Thomas A. (Proctor & Gamble Company, West Chester, OH); Mrozek, Randy A. (Army Research Laboratory, Adelphi, MD); Lenhart, Joseph Ludlow (Army Research Laboratory, Adelphi, MD); Rao, Rekha Ranjana; Collins, Robert (Oak Ridge National Laboratory); Mondy, Lisa Ann
2011-09-01
Multilayer coextrusion has become a popular commercial process for producing complex polymeric products from soda bottles to reflective coatings. A numerical model of a multilayer coextrusion process is developed based on a finite element discretization and two different free-surface methods, an arbitrary-Lagrangian-Eulerian (ALE) moving mesh implementation and an Eulerian level set method, to understand the moving boundary problem associated with the polymer-polymer interface. The goal of this work is to have a numerical capability suitable for optimizing and troubleshooting the coextrusion process, circumventing flow instabilities such as ribbing and barring, and reducing variability in layer thickness. Though these instabilities can be both viscous and elastic in nature, for this work a generalized Newtonian description of the fluid is used. Models of varying degrees of complexity are investigated including stability analysis and direct three-dimensional finite element free surface approaches. The results of this work show how critical modeling can be to reduce build test cycles, improve material choices, and guide mold design.
Twisted and coiled ultralong multilayer graphene ribbons
International Nuclear Information System (INIS)
The mechanical behavior and properties of multilayer graphene sheets and nanoribbons have been a subject of intensive research in recent years, due to their potential in electronic, structural and thermal applications. Calculations of effective properties range from molecular dynamic simulations to use of structural mechanical continuum models. Here, structural and elastic parameters are obtained via full atomistic simulations, and a two-dimensional mesoscopic model for a sheet of graphene is developed utilizing coarse-grain bead-spring elements with rotational-spring potentials. The assertion of energy conservation between atomistic and mesoscale models through elastic strain energy is enforced to arrive at model parameters, incorporating normal and shear strains, out-of-plane bending and intramolecular interactions. We then apply our mesoscopic model to investigate the structure and conformational behavior of twisted ultralong multilayer graphene ribbons with lengths of hundreds of nanometers, representing several millions of individual atoms, beyond the accessible regime of full atomistic molecular dynamics. We find a distinct transition from a twisted (saddle-like) configuration to a helical (coil-like) configuration as a function of imposed rotation and number of graphene layers. Further, for single layer graphene ribbons, multiple, stable configurations occur at discrete rotations due to the surface adhesion. The model developed and applied here can be more generally used to investigate properties of other two-dimensional membrane and ribbon-like systems for mesoscale hierarchical material design
2014-07-09
Adult Anaplastic Astrocytoma; Adult Anaplastic Oligodendroglioma; Adult Giant Cell Glioblastoma; Adult Glioblastoma; Adult Gliosarcoma; Adult Grade I Meningioma; Adult Grade II Meningioma; Adult Grade III Meningioma; Adult Mixed Glioma; Recurrent Adult Brain Tumor
Surgical treatment of intra hepatic recurrence of hepatocellular carcinoma
Lacaze, Laurence; Scotté, Michel
2015-01-01
Recurrence after hepatocellular carcinoma (HCC) is frequent. Currently, there are no recommendations on therapeutic strategy after recurrence of HCC. Whereas the 5 year-recurrence rate after resection of HCC is 100%, this drops to 15% after primary liver transplantation. Repeat hepatectomy and salvage liver transplantation (SLT) could be performed in selected patients to treat recurrent HCC and enable prolonged overall survival after treatment of recurrence. Other therapies such as local ablation, chemoembolization or sorafenib could be proposed to those patients unable to benefit from resection or SLT. A clear definition of the place of SLT and “prophylactic” liver transplantation is required. Indeed, identifying risks factors for recurrence at time of primary liver resection of HCC may help to avoid recurrence beyond Milan criteria and non-resectable situations. In this review, we summarize the recent data available in the literature on the feasibility and outcomes of repeat hepatectomy and SLT as treatment for recurrent HCC.
Linear Recurrent Subsequences of Meta-Fibonacci Sequences
Fox, Nathan
2015-01-01
In a recent paper, Frank Ruskey asked whether every linear recurrent sequence can occur in some solution of a meta-Fibonacci sequence. In this paper, we answer his question in the affirmative for recurrences with positive coefficients.
If I Had - A Child with Recurrent Chest Infections
Full Text Available ... Help Treat Certain Medical Conditions If I Had - Child With Recurrent Chest Infections - Dr. Larry Lands, MD, ... University Back to Home Page If I Had - Child With Recurrent Chest Infections - Dr. Larry Lands, MD, ...
Factors predicting survival after post-transplant hepatocellular carcinoma recurrence
Toso, Christian; Cader, Sonia; Mentha-Dugerdil, Ariane; Meeberg, Glenda; Majno, Pietro; Morard, Isabelle; Giostra, Emiliano; Berney, Thierry; Morel, Philippe; MENTHA, Gilles; Kneteman, Norman M
2012-01-01
Although factors associated with an increased risk of recurrence after liver transplantation for hepatocellular carcinoma (HCC) have been extensively studied, the history of patients with a post-transplant recurrence is poorly known.
Recurrent Glomerulonephritis after Renal Transplantation: An Unsolved Problem
Golgert, William A.; Appel, Gerald B.; Hariharan, Sundaram
2008-01-01
Background and objectives: Despite advances in prevention of acute rejection and improved short- and long-term kidney graft survival, recurrent glomerulonephritis remains problematic and poorly characterized. This study analyzed prevalence and outcome of recurrent glomerulonephritis from various registries.
Recurrent Dreams and Psychosocial Adjustment in Preteenaged Children
Gauchat, Aline; Zadra, Antonio; Tremblay, Richard E.; Zelazo, Philip David; Séguin, Jean. R.
2009-01-01
Research indicates that recurrent dreams in adults are associated with impoverished psychological well-being. Whether similar associations exist in children remains unknown. The authors hypothesized that children reporting recurrent dreams would show poorer psychosocial adjustment than children without recurrent dreams. One hundred sixty-eight 11-year-old children self-reported on their recurrent dreams and on measures of psychosocial adjustment. Although 35% of children reported having exper...
Thalidomide in Treating Patients With Recurrent or Persistent Endometrial Cancer
2013-01-23
Endometrial Adenoacanthoma; Endometrial Adenocarcinoma; Endometrial Adenosquamous Cell Carcinoma; Endometrial Clear Cell Carcinoma; Endometrial Papillary Serous Carcinoma; Recurrent Endometrial Carcinoma
Does psychiatric illness affect the recurrence rate of genital herpes?
Goldmeier, D; A Johnson
1982-01-01
The progress of 58 patients with first attacks of genital herpes was monitored for up to 30 weeks. The effects of sex (gender), age, social class, and non-psychotic psychiatric illness (as measured by the "general health questionnaire," GHQ) on the recurrence rate of herpes was studied. The recurrence rates, measured by the actuarial percentage recurrence-free curves, showed that the 29 patients with GHQ scores above 11 had a significantly higher recurrence rate than those who scored less tha...
Imaging metallic multilayer structures through ultrafast optically driven quasiparticle transport
Bron, W. E.; Guerra, A.; Suárez, C.
1996-03-01
It has recently been demonstrated that ultrashort excitation of quasiparticles by femtosecond laser pulses in thin metallic films leads to nonequilibrium particle dynamics and nonthermal transport. In a specific geometry of ultrathin metallic multilayers the effective driving force for the transport is a linear concentration gradient of nonequilibrium quasiparticles that exists between excited and unexcited volumes. The dynamics of excited particles are shown to be governed by Fermi-Liquid Theory. We report here on an advancement of this topic and demonstrate that this phenomena can be used to ``image" otherwise hidden components of metallic multilayers. Specifically we report on the transport of nonequilibrium electrons through multilayers composed of AuTiAu films. The results are compared to a Au film deposited next to the multilayer film. The experimental observation of the fractional change in the reflectivity ? R/R is dependent on which component of the multilayer component is being interrogated. The difference in reflectivity between pure gold and the multilayer film is being considered to result from stronger electron-phonon coupling in titanium. The discontinuity of the transport across the interface is clearly observed. ``Images" of more complicated multilayer geometries will also be presented.
Tuning the electrochemical swelling of polyelectrolyte multilayers toward nanoactuation.
Zahn, Raphael; Vörös, János; Zambelli, Tomaso
2014-10-14
We discuss physicochemical determinants of electrochemical polyelectrolyte multilayer swelling that are relevant to actuator usage. We used electrochemical quartz crystal microbalance with dissipation monitoring (EC-QCM-D) and cyclic voltammetry to compare the electrochemical swelling of two types of ferrocyanide-containing polyelectrolyte multilayers, poly(l-glutamic acid)/poly(allylamine hydrochloride) (PGA/PAH), and carboxymethyl cellulose/poly(diallyldimethylammonium chloride) (CMC/PDDA). We showed that ferrocyanide oxidation causes the swelling of PGA/PAH multilayers whereas it results in the contraction of CMC/PDDA multilayers. This behavior can be attributed to the presence of a positive and a negative Donnan potential in the case of PGA/PAH and CMC/PDDA multilayers, respectively. Using multilayers consisting of PGA and poly(allylamine) ferrocene (PGA/PAH-FC), we applied EC-QCM-D and demonstrated potentiostatic thickness control with nanometer precision and showed that the multilayer's thickness depends linearly on the applied potential within a certain potential range. PMID:25229875
Extended asymmetric-cut multilayer X-ray gratings.
Prasciolu, Mauro; Haase, Anton; Scholze, Frank; Chapman, Henry N; Bajt, Saša
2015-06-15
The fabrication and characterization of a large-area high-dispersion blazed grating for soft X-rays based on an asymmetric-cut multilayer structure is reported. An asymmetric-cut multilayer structure acts as a perfect blazed grating of high efficiency that exhibits a single diffracted order, as described by dynamical diffraction throughout the depth of the layered structure. The maximum number of grating periods created by cutting a multilayer deposited on a flat substrate is equal to the number of layers deposited, which limits the size of the grating. The size limitation was overcome by depositing the multilayer onto a substrate which itself is a coarse blazed grating and then polish it flat to reveal the uniformly spaced layers of the multilayer. The number of deposited layers required is such that the multilayer thickness exceeds the step height of the substrate structure. The method is demonstrated by fabricating a 27,060 line pairs per mm blazed grating (36.95 nm period) that is repeated every 3,200 periods by the 120-?m period substrate structure. This preparation technique also relaxes the requirements on stress control and interface roughness of the multilayer film. The dispersion and efficiency of the grating is demonstrated for soft X-rays of 13.2 nm wavelength. PMID:26193502
Recurrent Klebsiella pneumoniae Liver Abscess: Clinical and Microbiological Characteristics?
Yang, Ya-Sung; Siu, L. K.; Yeh, Kuo-Ming; Fung, Chang-Phong; Huang, Shenq-Jie; Hung, Han-Chang; Lin, Jung-Chung; Chang, Feng-Yee
2009-01-01
Recurrent Klebsiella pneumoniae liver abscesses (KLAs) are rarely reported. Six cases of recurrent KLAs are characterized. Most of the patients had diabetes and K1 serotype KLAs. All of the isolates were uniformly susceptible to cefazolin. Distinct molecular fingerprints were found for the strains isolated from both primary and recurrent KLAs.
Multilayer stochastic block models reveal the multilayer structure of complex networks
Valles-Catala, Toni; Guimera, Roger; Sales-Pardo, Marta
2014-01-01
In complex systems, the network of interactions we observe between system's components is the aggregate of the interactions that occur through different mechanisms or layers. Recent studies reveal that the existence of multiple interaction layers can have a dramatic impact in the dynamical processes occurring on these systems. However, these studies assume that the interactions between systems components in each one of the layers are known, while typically for real-world systems we do not have that information. Here, we address the issue of uncovering the different interaction layers from aggregate data by introducing multilayer stochastic block models (SBMs), a generalization of single-layer SBMs that considers different mechanisms of layer aggregation. First, we find the complete probabilistic solution to the problem of finding the optimal multilayer SBM for a given aggregate observed network. Because this solution is computationally intractable, we propose an approximation that enables us to verify that mu...
Polymerization of hydrocarbon and fluorocarbon amphiphiles in Langmuir-Blodgett multilayers
Laschewsky, André; Ringsdorf, H.; Schmidt, G
1985-01-01
Langmuir-Blodgett multilayers of polymerizable carboxylic acids with hydrocarbon or fluorocarbon chains were prepared. The multilayers were polymerized by UV light and the reactions were studied by UV/visible spectroscopy. The polyreactions strongly influence the multilayer structures which were investigated by X-ray small-angle scattering and scanning electron microscopy. The spreading behaviour of the monomers, the preparation of multilayers, their reactivities in multilayers and structural...
Directory of Open Access Journals (Sweden)
Kasetsuwan N
2015-09-01
Full Text Available Ngamjit Kasetsuwan, Kanokorn Sakpisuttivanit, Usanee Reinprayoon, Vilavun Puangsricharern Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand Objective: To assess the recurrent rate, mean survival time, and risk factors associated with recurrent painful bullous keratopathy (BK after primary treatment with phototherapeutic keratectomy.Methods: Medical records from 72 patients (72 eyes who had phototherapeutic keratectomy for painful BK were evaluated. Data for sex, age, duration of BK, associated ocular and systemic diseases (hypertension, diabetes mellitus, ischemic heart disease, asthma, dyslipidemia, and rheumatoid arthritis, frequency and degree of pain (grade 1–3, visual acuity, corneal thickness, intraocular pressure, and laser setting were extracted and analyzed.Results: The mean age of the patients was 64.2±11.4 years. The mean preoperative duration of BK was 15.0±11.0 months. Most patients had pseudophakic BK (69.40%. Majority of the cases had grade 3 degree of pain (48.60%. Glaucoma and hypertension were markedly found among these patients (51.40% and 19.40%, respectively. Preoperative mean intraocular pressure and corneal thickness were 13.70±4.95 mmHg and 734.1±83.80 µm, respectively. The mean laser diameter and depth were 8.36±1.22 mm and 38.89±8.81 µm, respectively. Systemic disease was significantly associated with the risk for developing recurrent painful BK (P=0.022, hazard ratio [HR] 1.673, 95% confidence interval [CI] 1.08–2.58. The overall recurrent rate was 51%. The average duration time of recurrent painful BK was 17.3±12.9 months (range 1–50 months. The median survival time before recurrence was 29.0±6.6 months.Conclusion: Systemic disease was found to be the only risk factor significantly associated with the development of recurrent painful BK. Low recurrent rate and long mean survival time showed that phototherapeutic keratectomy was effective in relieving recurrent painful BK and can be used as an alternative procedure for patients waiting for corneal transplantation. Keywords: bullous keratopathy, recurrent painful, phototherapeutic keratectomy, PTK, risk factor, mean survival time
Origin of cracking in nanoscale Cu/Ta multilayers
International Nuclear Information System (INIS)
Cracking behaviors in nanoscale Cu/Ta multilayers bonded to polyimide substrates have been investigated by uniaxial tensile tests. Experimental results show that cracks originate from the localized deformation regions associated with aligned grain boundaries. Microscopical observations suggest that the alignment of the grain boundaries is caused by local grain boundary sliding and grain rotation, which resulted in the in-plane and out-of-plane cooperative movements of the grains in the multilayers. From the localized damage regions, shear fracture in the through-thickness direction occurred in the nanoscale Cu/Ta multilayer
Performance of multilayer coated carbide tools when turning cast iron
Y???T, Recep; FINDIK, Fehim; ÇEL?K, Erdal
2009-01-01
The tool life performance of multilayer hard coatings was evaluated for machining of spheroidal graphite cast iron. TiCN+TiC+Al2O3+TiN and TiCN+TiC+Al2O3+TiN multilayered coatings with different thicknesses were fabricated on WC substrates using high temperature chemical vapor deposition (HTCVD). These cutting tools with hard multilayered coating systems were used in the longitudinal turning of spheroidal graphite cast iron under the cutting conditions encountered in the work. To inv...
Effect of surface roughness on multilayer film growth
Modi, M. H.; Rai, S. K.; Thomasset, M.; Lodha, G. S.; Idir, M.
2009-02-01
NbC/Si multilayers grown on silicon substrates of different roughness have been used to study the influence of surface quality on growth characteristics. Surface morphology of substrate and multilayer film are characterized by topographic measurements using atomic force microscopy (AFM) technique and power spectral density analysis (PSD). Grazing incidence x-ray reflectivity (GIXR) technique in combination with PSD analysis reveals a growth characteristic of multilayer film on substrates of different roughness. It is revealed that the stochastic growth of NbC on rough substrate leads to formation of clusters of varying size depending on initial substrate roughness. Details of growth characteristic are discussed.
Multilayer bandpass filter with extended lower and upper stop bands.
Belyaev, B A; Tyurnev, V V
2015-09-15
We propose a novel design for a multilayer bandpass filter in which every resonant dielectric layer is separated from adjacent dielectric layers or from the ambient by a nonresonant grating of strip conductors on the layer interface. Here, every grating acts as a mirror with specified transparency. Relative to the conventional multilayer bandpass filter with multilayer dielectric mirrors, the proposed filter has multiply extended stop bands below and above the passband. Additionally, we provide formulas for computing the filter's frequency response. A comparison between the computed frequency responses for the proposed and conventional filters with the same passband is presented. PMID:26371929
Magnetization reversal of Co/Pd multilayers on nanoporous templates
Huang, Chien-Chih; Yu, Chin-Chung; Chen, Shih-Yuan; Yao, Yeong-Der; Lai, Jun-Yang
2012-01-01
By making use of an e-beam deposition system, the [Co(2 Å)/Pd(10 Å)]15 multilayers were prepared on a Si(100) substrate and anodized aluminum oxide [AAO] templates with average pore diameters of around 185, 95, and 40 nm. The mechanism of magnetization reversal of the Co/Pd multilayers was investigated. Wall motion was observed on the Co/Pd multilayers grown on the Si substrate. A combination of wall motion and domain rotation was found in the sample grown on the AAO template with a 185-nm po...
On degree-degree correlations in multilayer networks
de Arruda, Guilherme Ferraz; Moreno, Yamir; Rodrigues, Francisco A
2015-01-01
We propose a generalization of the concept of assortativity based on the tensorial representation of multilayer networks, covering the definitions given in terms of Pearson and Spearman coefficients. Our approach can also be applied to weighted networks and provides information about correlations considering pairs of layers. By analyzing the multilayer representation of the airport transportation network, we show that contrasting results are obtained when the layers are analyzed independently or as an interconnected system. Finally, we study the impact of the level of assortativity and heterogeneity between layers on the spreading of diseases. Our results highlight the need of studying degree-degree correlations on multilayer systems, instead of on aggregated networks.
Recurrent breast cancer after segmental resection and radiation treatment
International Nuclear Information System (INIS)
To determine the clinical and mammographic features of recurrent breast cancer after lumpectomy and radiation therapy, the authors have reviewed the clinical history and serial mammograms of 25 patients who developed recurrence and 25 patients with suspected recurrence in whom the biopsies were benign. In patients developing recurrence, 32% had positive mammograms alone, 28% had positive physical examinations alone, and 40% had both positive mammograms and physical examination. Positive mammographic findings include developing calcifications, mass, increasing density, or skin thickening. Patients diagnosed on mammography alone had lower systemic failure. The authors concluded that serial mammographic and clinical examinations are complementary for detection of recurrence
Late local recurrence of tongue carcinoma after radiation therapy
International Nuclear Information System (INIS)
Nine patients with local recurrence more than 5 years after intial treatment of tongue carcinoma were studied. The intervals between initial brachytherapy and local recurrence were 5.3 to 19.3 years. The incidence of recurrence was 7.1% of 84 patients in both T1 and T2 tumors. In most cases, the recurrent lesion was near the marginal portion of the initial lesion. We speculate that the recurrence may be attributable to residual tumor over looked during the initial procedure. (author)
Recurrent Respiratory Papillomatosis: an Extensive Review
Directory of Open Access Journals (Sweden)
Angelou Valerie
2012-07-01
Full Text Available Recurrent respiratory papillomatosis (RRP is characterized by the recurrence of benign tumors (papillomata in the aero digestive tract caused by Human Papilloma Virus. The burden for the patient and the society is non negligible, due to the high frequency of repetitive surgeries. The disease follows a bimodal age distribution. Usually the very first manifestation is hoarseness or voice changes but if negligee it can cause airway obstruction resulting in respiratorystridor or acute respiratory distress The treatment is challenging, includes surgery (mostly CO2 laser and adjuvant medical therapy is almost always required (Cidofovir, interferon a, and others. The risk of malignant transformation is not negligent. Advances in immunology will lead us to understand the biology of HPV and will permit successful therapies. Prophylactic HPV vaccines are a promising area of research concerning RRP
Supervised Sequence Labelling with Recurrent Neural Networks
Graves, Alex
2012-01-01
Supervised sequence labelling is a vital area of machine learning, encompassing tasks such as speech, handwriting and gesture recognition, protein secondary structure prediction and part-of-speech tagging. Recurrent neural networks are powerful sequence learning tools—robust to input noise and distortion, able to exploit long-range contextual information—that would seem ideally suited to such problems. However their role in large-scale sequence labelling systems has so far been auxiliary. The goal of this book is a complete framework for classifying and transcribing sequential data with recurrent neural networks only. Three main innovations are introduced in order to realise this goal. Firstly, the connectionist temporal classification output layer allows the framework to be trained with unsegmented target sequences, such as phoneme-level speech transcriptions; this is in contrast to previous connectionist approaches, which were dependent on error-prone prior segmentation. Secondly, multidimensional...
Multi-Dimensional Recurrent Neural Networks
Graves, Alex; Schmidhuber, Juergen
2007-01-01
Recurrent neural networks (RNNs) have proved effective at one dimensional sequence learning tasks, such as speech and online handwriting recognition. Some of the properties that make RNNs suitable for such tasks, for example robustness to input warping, and the ability to access contextual information, are also desirable in multidimensional domains. However, there has so far been no direct way of applying RNNs to data with more than one spatio-temporal dimension. This paper introduces multi-dimensional recurrent neural networks (MDRNNs), thereby extending the potential applicability of RNNs to vision, video processing, medical imaging and many other areas, while avoiding the scaling problems that have plagued other multi-dimensional models. Experimental results are provided for two image segmentation tasks.
An unusual cause for recurrent chest infections.
LENUS (Irish Health Repository)
Lobo, Ronstan
2012-10-01
We present a case of an elderly non-smoking gentleman who, since 2005, had been admitted multiple times for recurrent episodes of shortness of breath, wheeze, cough and sputum. The patient was treated as exacerbations of chronic obstructive pulmonary disease (COPD) and\\/or lower respiratory tract infections. Bronchoscopy was done which revealed multiple hard nodules in the trachea and bronchi with posterior tracheal wall sparing. Biopsies confirmed this as tracheopathia osteochondroplastica (TO). He had increasing frequency of admission due to methicillin-resistant Staphylococcus aureus and pseudomonas infections, which failed to clear despite intravenous, prolonged oral and nebulised antibiotics. The patient developed increasing respiratory distress and respiratory failure. The patient died peacefully in 2012. This case report highlights the typical pathological and radiological findings of TO and the pitfalls of misdiagnosing patients with recurrent chest infections as COPD.
Human papillomavirus types and recurrent cervical warts
International Nuclear Information System (INIS)
The authors analyzed cervical intraepithelial neoplasias (CINs) detected after cryotherapy to determine if recurrence is associated with the same human papillomavirus (HPV) type found in the original lesion. Eight women had detectable HPV DNA in CINs that occurred after ablation of another CIN, and for each patient the HPV type in the pretreatment lesion was different from that in the CIN that appeared after cryotherapy. This compares with 12 women who had HPV detected in two or more CINs present at the same time, 11 of whom had the same HPv type noted. they concluded that although multiple, simultaneous CINs in a woman often contain the same HPV type, recurrent CINs that occur after cryotherapy contain an HPV type different from that present in the pretreatment lesion
Radiotherapeutic alternatives for previously irradiated recurrent gliomas
International Nuclear Information System (INIS)
Re-irradiation for recurrent gliomas has been discussed controversially in the past. This was mainly due to only marginal palliation while being associated with a high risk for side effects using conventional radiotherapy. With modern high-precision radiotherapy re-irradiation has become a more wide-spread, effective and well-tolerated treatment option. Besides external beam radiotherapy, a number of invasive and/or intraoperative radiation techniques have been evaluated in patients with recurrent gliomas. The present article is a review on the available methods in radiation oncology and summarizes results with respect to outcome and side effects in comparison to clinical results after neurosurgical resection or different chemotherapeutic approaches
Influence of Observational Noise On Recurrence Plots
Romano, C.; Thiel, M.; Kurths, J.
The methods of recurrence plots (RP's) and recurrence quantification analyis (RQA) have become widely applied tools for data analysis. Nevertheless, until recently, the interpretation was mainly a matter of experience due to a lacking mathematical formulation for these methods. Now the mathematical fun- damentals have been scrutinized (see the contribution of Thiel et al. in this session). But there is still another problem applying RP's and RQA to experimental data. The influence of the observational noise on the results of both methods is a crucial point for their interpretation. We present the results of the estimation of these effects on RP's and RQA. We further show how to reduce the errors due to the observational noise by a suitable choice of parameters needed for the computation of the RP's.
Recurrent syncope and chronic ear pain.
Clegg, Andrew; Daverede, Luis; Wong, Winson; Loney, Elizabeth; Young, John
2010-01-01
An elderly gentleman presented to hospital with recurrent blackout episodes consistent with syncope and a 3-month history of right ear pain. Significant postural hypotension was recorded. White cell count and C reactive protein were elevated. MRI of the head and neck revealed a soft tissue abnormality in the right nasopharynx and base of skull. Tissue biopsies were obtained and microbiology specimens revealed a mixed growth of pseudomonas and diphtheroids. There was no histological evidence of malignancy. A diagnosis of skull base infection was made. Infective involvement of the carotid sinus was considered to be the cause of the recurrent syncope and postural hypotension. The patient responded well to a 12-week course of intravenous meropenem. Inflammatory markers returned to normal and a repeat MRI after 3 months of treatment showed significant resolution of infection. The syncopal episodes and orthostatic hypotension resolved in parallel with treatment of infection. PMID:22791782
On explicit formulae and linear recurrent sequences
Directory of Open Access Journals (Sweden)
L. H. Gallardo
2011-09-01
Full Text Available We notice that some recent explicit results about linear recurrent sequences over a ring R with 1 were already obtained by Agou in a 1971 paper by considering the euclidean division of polynomials over R. In this paper we study an application of these results to the case when R = Fq[t] and q is even, completing Agou's work. Moreover, for even q we prove that there is an infinity of indices i such that gi = 0 for the linear recurrent, Fibonacci-like, sequence defined by g0 = 0, g1 = 1 and gn + 1 = gn + D gn - 1 for n > 1, where D is any nonzero polynomial in R = Fq[t] A new identity is established.
Recurrent respiratory papillomatosis: current and future perspectives.
Carifi, Marco; Napolitano, Domenico; Morandi, Morando; Dall'Olio, Danilo
2015-01-01
Although recurrent respiratory papillomatosis is a benign disease of the upper aerodigestive tract caused by infection with human papillomavirus, the disease process is unpredictable, ranging from mild disease and spontaneous remission to an aggressive disease with pulmonary spread and requirement for frequent surgical debulking procedures. It can present a protracted clinical course and cause potentially life-threatening compromise of the airways. Over recent decades, a number of alternative medical therapies to standard surgical treatment have been investigated, with modest outcomes overall. Currently, some additional therapies are being explored, together with novel surgical instrumentation that can help to avoid inevitable long-term stenotic complications, ultimately affecting quality of life. Hopefully, clinicians might soon be able to significantly improve the quality of treatment and outcomes for patients affected with recurrent respiratory papillomatosis, with human papillomavirus vaccination having a potentially important role. PMID:25999724
Recurrent Oligodendroglioma Treated with Acupuncture and Pharmacopuncture.
Kim, Jae Soo; Lee, Hyun Jong; Lee, Sang Hoon; Lee, Bong Hyo
2015-06-01
Acupuncture and pharmacopuncture have been shown to be effective in tumor treatment. However, their effectiveness for treating oligodendroglioma has not been reported yet. The purpose of this study was to provide an initial report on the effectiveness of acupuncture and pharmacopuncture for the treatment of an oligodendroglioma by presenting a case that was treated successfully. A 54-year-old man, who had experienced intracranial hemorrhage, was diagnosed with recurrent oligodendroglioma. His expected survival period was 3-6 months. The patient received daily acupuncture and weekly pharmacopuncture of mountain ginseng and bee venom. After treatment for 18 months, the tumor size was decreased markedly on brain magnetic resonance imaging, and severe seizures had disappeared. In this case, a combination of acupuncture and pharmacopuncture was shown to be effective for the treatment of recurrent oligodendroglioma. PMID:26100069
The nutrition consult for recurrent stone formers.
Penniston, Kristina L
2015-07-01
Diet is implicated in stone formation and growth. Whether alone or in concert with pharmacologics, dietary changes may be useful in reducing recurrence but only when they correct dietary stone-forming risks. Patients benefit from recommendations individualized to their food preferences as well as to lifestyle, age, food knowledge and access, preparation skills, and cultural and ethnic identities. Urologists can provide general dietary recommendations but often lack the time to provide the full complement of individualized nutrition care offered by a registered dietitian nutritionist (RDN). Urologists can partner with and refer patients to a RDN for any component of the nutrition care process: assessment of diet, diagnosis of dietary factors that contribute to stone risk factors, intervention formulation and implementation, and monitoring the effectiveness of the intervention and modifying it as needed to maintain suitably low dietary risk for stone recurrence. PMID:26025494
A multilayer surface detector for ultracold neutrons
Wang, Zhehui; Callahan, N B; Adamek, E R; Bacon, J D; Blatnik, M; Brandt, A E; Broussard, L J; Clayton, S M; Cude-Woods, C; Currie, S; Dees, E B; Ding, X; Gao, J; Gray, F E; Hoffbauer, M A; Holley, A T; Ito, T M; Liu, C -Y; Makela, M; Ramsey, J C; Pattie,, R W; Salvat, D J; Saunders, A; Schmidt, D W; Schulze, R K; Seestrom, S J; Sharapov, E I; Sprow, A; Tang, Z; Wei, W; Wexler, J W; Womack, T L; Young, A R; Zeck, B A
2015-01-01
A multilayer surface detector for ultracold neutrons (UCNs) is described. The top $^{10}$B layer is exposed to the vacuum chamber and directly captures UCNs. The ZnS:Ag layer beneath the $^{10}$B layer is a few microns thick, which is sufficient to detect the charged particles from the $^{10}$B(n,$\\alpha$)$^7$Li neutron-capture reaction, while thin enough so that ample light due to $\\alpha$ and $^7$Li escapes for detection by photomultiplier tubes. One-hundred-nm thick $^{10}$B layer gives high UCN detection efficiency, as determined by the mean UCN kinetic energy, detector materials and others. Low background, including negligible sensitivity to ambient neutrons, has also been verified through pulse-shape analysis and comparisons with other existing $^3$He and $^{10}$B detectors. This type of detector has been configured in different ways for UCN flux monitoring, development of UCN guides and neutron lifetime research.
Multilayer Multiconfiguration Time-Dependent Hartree Theory.
Wang, Haobin
2015-07-23
Multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) theory is a rigorous and powerful method to simulate quantum dynamics in complex many-body systems. This approach extends the original MCTDH theory of Meyer, Manthe, and Cederbaum to include dynamically contracted layers in a recursive way, within which the equations of motion are determined from the Dirac-Frenkel variational principle. This paper presents the general derivation of the theory and analyzes the important features that make the ML-MCTDH method numerically efficient. Furthermore, we discuss the generalization of the theory to treat many-body identical particles (fermions or bosons) as well as calculating energy eigenstates via the improved relaxation method. PMID:26020459
Multilayer Statistical Intrusion Detection in Wireless Networks
Directory of Open Access Journals (Sweden)
Noureddine Boudriga
2008-12-01
Full Text Available The rapid proliferation of mobile applications and services has introduced new vulnerabilities that do not exist in fixed wired networks. Traditional security mechanisms, such as access control and encryption, turn out to be inefficient in modern wireless networks. Given the shortcomings of the protection mechanisms, an important research focuses in intrusion detection systems (IDSs. This paper proposes a multilayer statistical intrusion detection framework for wireless networks. The architecture is adequate to wireless networks because the underlying detection models rely on radio parameters and traffic models. Accurate correlation between radio and traffic anomalies allows enhancing the efficiency of the IDS. A radio signal fingerprinting technique based on the maximal overlap discrete wavelet transform (MODWT is developed. Moreover, a geometric clustering algorithm is presented. Depending on the characteristics of the fingerprinting technique, the clustering algorithm permits to control the false positive and false negative rates. Finally, simulation experiments have been carried out to validate the proposed IDS.
Multilayer Bit Allocation for Video Encoding
Directory of Open Access Journals (Sweden)
Elavarasan.R
2011-05-01
Full Text Available Video compression approach removes spatial and temporal redundancy based on the signal statisticalcorrelation. Bit allocation technique adopts a visual distortion model for a better rate visual distortionvideo coding. Visual distortion model uses both motion and the texture structures in the video sequences.The existing video coding mechanisms reduces the bit rate for video coding. However to get better videocompression ratio there is a need for multilayer compression technique. In this paper we proposed amultilayer bit allocation video coding mechanism. The proposed model reduces the bit allocation for videocoding by retaining the same video quality. The experimental results using the proposed model reduced thebit rate by 3% to 4%. The result are promising. Finally we conclude with conclusion and future work.
Plasmon Resonance in Multilayer Graphene Nanoribbons
Emani, Naresh Kumar; Chung, Ting-Fung; Prokopeva, Ludmila J; Kildishev, Alexander V; Shalaev, Vladimir M; Chen, Yong P; Boltasseva, Alexandra
2015-01-01
Plasmon resonance in nanopatterned single layer graphene nanoribbon (SL-GNR), double layer graphene nanoribbon (DL-GNR) and triple layer graphene nanoribbon (TL-GNR) structures is studied both experimentally and by numerical simulations. We use 'realistic' graphene samples in our experiments to identify the key bottle necks in both experiments and theoretical models. The existence of electrical tunable plasmons in such stacked multilayer GNRs was first experimentally verified by infrared microscopy. We find that the strength of the plasmonic resonance increases in DL-GNR when compared to SL-GNRs. However, we do not find a further such increase in TL-GNRs compared to DL-GNRs. We carried out systematic full wave simulations using finite element technique to validate and fit experimental results, and extract the carrier scattering rate as a fitting parameter. The numerical simulations show remarkable agreement with experiments for unpatterned SLG sheet, and a qualitative agreement for patterned graphene sheet. W...
Heat transfer processes in multilayer building structures
International Nuclear Information System (INIS)
The thermal behaviour of rooms and buildings is essentially characterized by the instationary heat transfer behaviour of room enclosing, intransparent building structure (i.e. walls). The paper gives a summarized description of heat transfer processes in single and multilayer building components within the frequency area. Furthermore, the application of a procedure for the approximation of frequency pattern by broken rational functions on the results of the analysis. This approximation guides to mathematical models for the instationary heat transfer behaviour of the nontransparent building components, to be solved easily and directly with the wellknown simulation processes of a digital computer. The process is investigated as to his degree of accuracy and compared with a method using differences. (orig.)
Topological Crystalline Insulator Phase in Graphene Multilayers
Kindermann, M.
2015-06-01
While the experimental progress on three dimensional topological insulators is rapid, the development of their 2D counterparts has been comparatively slow, despite their technological promise. The main reason is materials challenges of the to date only realizations of 2D topological insulators, in semiconductor quantum wells. Here we identify a 2D topological insulator in a material which does not face similar challenges and which is by now most widely available and well charaterized: graphene. For certain commensurate interlayer twists, graphene multilayers are insulators with sizable band gaps. We show that they are moreover in a topological phase protected by crystal symmetry. As its fundamental signature, this topological state supports one-dimensional boundary modes. They form low-dissipation quantum wires that can be defined purely electrostatically.
PROACTIVE NETWORK SECURITYAPPROACH FOR MULTILAYERED ARCHITECURE
Directory of Open Access Journals (Sweden)
Lalitha Kumari R
2013-06-01
Full Text Available In order to fulfill the organization goals and objectives, multilayered network architecture and various heterogeneous server environments are used. As the network architectures are complex, there is an increased demand in information security. So each organization needs to provide sufficient network security for the known and the unknown attacks according to its goals, requirements and objectives. Highly skilled hacker’s everyday discovers the new threats in order to break the security bridge in each organization. Hence the organizations are forced to revise their security policies in order to handle the network vulnerabilities that are increasing day by day. So to handle this issue a proactive network strategy is proposed against network vulnerabilities such as fraud, information leakage, denial of service attack and so on. By this approach the network is scanned periodically and the threats are prioritized andevaluated accordingly.
Fast multilayer fission chamber with 239Pu
International Nuclear Information System (INIS)
For the investigation of neutron induced fission of heavy nuclei in the resonance energy range, a fast multilayer ionization fission chamber with a 239Pu content of 1.6 g was constructed. The chamber is compact and a minimum of material has been used for its construction. There is not more than 100 mg of plutonium in every section whose intrinsic capacity is less than 100 pF. By using fast preamplifiers and constant fraction discriminators, together with the combined method of amplitude and pulse length discrimination the background due to ?-particles is suppressed and a less perturbed pulse height distribution is obtained. The absolute fission fragment detection efficiency of the chamber is (60±8)%. Its time resolution does not exceed 2.6 ns
An ultra-broadband multilayered graphene absorber
Amin, Muhammad
2013-01-01
An ultra-broadband multilayered graphene absorber operating at terahertz (THz) frequencies is proposed. The absorber design makes use of three mechanisms: (i) The graphene layers are asymmetrically patterned to support higher order surface plasmon modes that destructively interfere with the dipolar mode and generate electromagnetically induced absorption. (ii) The patterned graphene layers biased at different gate voltages backedup with dielectric substrates are stacked on top of each other. The resulting absorber is polarization dependent but has an ultra-broadband of operation. (iii) Graphene\\'s damping factor is increased by lowering its electron mobility to 1000cm 2=Vs. Indeed, numerical experiments demonstrate that with only three layers, bandwidth of 90% absorption can be extended upto 7THz, which is drastically larger than only few THz of bandwidth that can be achieved with existing metallic/graphene absorbers. © 2013 Optical Society of America.
Chronic Recurrent Multifocal Osteomyelitis: A Case Report
Sadeghi, E; Kadivar, M R; Ghadimi moghadam, A K; Pooladfar, Gh R; Sadeghi, N (Nader)
2011-01-01
Chronic recurrent multifocal osteomyelitis (CRMO) is a rare inflammatory bone disease. It is a diagnosis of exclusion based on the clinical, radiological and pathological criteria. The awareness of the corresponding feature can help avoid of unnecessary diagnostic procedures and prolonged antibiotic therapy. We present a case of 4.5 year old girl, diagnosed with CRMO who were followed for 6 months as a case of chronic bacterial osteomyelitis and received long course of antibiotic therapy.
Chronic recurrent multifocal osteomyelitis: a case report.
Sadeghi, E; Kadivar, M R; Ghadimi Moghadam, A K; Pooladfar, Gh R; Sadeghi, N
2011-01-01
Chronic recurrent multifocal osteomyelitis (CRMO) is a rare inflammatory bone disease. It is a diagnosis of exclusion based on the clinical, radiological and pathological criteria. The awareness of the corresponding feature can help avoid of unnecessary diagnostic procedures and prolonged antibiotic therapy. We present a case of 4.5 year old girl, diagnosed with CRMO who were followed for 6 months as a case of chronic bacterial osteomyelitis and received long course of antibiotic therapy. PMID:22946018
Recurrent Deep Vein Thrombosis due to Thrombophilia
Rahman, Afzalur; Islam, AKM Monwarul; Husnayen, SAM
2012-01-01
Deep vein thrombosis (DVT) is a common condition that is often under-diagnosed. Acquired or hereditary defects of coagulation or a combination of these defects may facilitate the development of DVT. Recurrent DVT, a positive family history or unusual presentation may warrant investigation for hereditary thrombophilia. Investigations are best when conducted at least one month after completion of a course of anticoagulant therapy. Most patients are managed with heparin in the acute stage overla...
Recurrent Benign Myoepithelioma of the Auricle
Oh, Se-Joon; Kong, Soo-Keun; Lee, Il-Woo; Goh, Eui-Kyung
2014-01-01
Myoepithelioma, a generally benign tumor comprised of myoepithlial cells, is an uncommon salivary gland tumor. Myoepithelioma originates primarily in the parotid gland, but several isolated cases have been described. Although myoepithelioma has a benign nature, but there is a potential risk of malignant change and recurrence in case of incomplete resection. We acknowledge that benign myoepithelioma originating from the auricle has not been reported in the English literature. We present a rare...
Recurrent Vertigo: Is it Takayasu's Arteritis?
Tiwari Ashutosh; Kumar Nilesh; Varshney Ankur Nandan; Behera Dibyaranjan; Anand Arvind; Anand Ravi; N K Singh
2013-01-01
Takayasu's arteritis (TA) is a chronic, idiopathic, inflammatory disease, that is more common in females and Asian countries. A 38-year-old female presented with recurrent vertigo. Detailed examination revealed discrepancies in peripheral pulses and raised blood pressure in bilateral lower limbs. Possibility of vasculitis involving arch of aorta or its branches was kept. Investigations were suggestive of Takayasu's arteritis, and noncontrast tomographic scanning (NCCT) of head showed B/L pari...
Generating Sequences With Recurrent Neural Networks
Graves, Alex
2013-01-01
This paper shows how Long Short-term Memory recurrent neural networks can be used to generate complex sequences with long-range structure, simply by predicting one data point at a time. The approach is demonstrated for text (where the data are discrete) and online handwriting (where the data are real-valued). It is then extended to handwriting synthesis by allowing the network to condition its predictions on a text sequence. The resulting system is able to generate highly re...
Correlations in nuclear energy recurrence relations
Buck, B.; Merchant, A. C.; Perez, S. M.
2014-05-01
The excitation energies of states belonging to the ground state bands of heavy even-even nuclei are analysed using recurrence relations. Excellent agreement with experimental data at the 10 keV level is obtained by taking into account strong correlations which emerge in the analysis. This implies that the excitation energies can be written as a polynomial of maximum degree 4 in the angular momentum.
Correlations in nuclear energy recurrence relations
Buck, B; Perez, S M
2013-01-01
The excitation energies of states belonging to the ground state bands of heavy even-even nuclei are analysed using recurrence relations. Excellent agreement with experimental data at the 10 keV level is obtained by taking into account strong correlations which emerge in the analysis. This implies that the excitation energies can be written as a polynomial of maximum degree four in the angular momentum.
Comment on "Recurrences without closed orbits"
J. Main
1999-01-01
In a recent paper Robicheaux and Shaw [Phys. Rev. A 58, 1043 (1998)] calculate the recurrence spectra of atoms in electric fields with non-vanishing angular momentum not equal to 0. Features are observed at scaled actions ``an order of magnitude shorter than for any classical closed orbit of this system.'' We investigate the transition from zero to nonzero angular momentum and demonstrate the existence of short closed orbits with L_z not equal to 0. The real and complex ``g...
Rhythmicity, Recurrence, and Recovery of Flagellar Beating
Wan, Kirsty Y.; Goldstein, Raymond E.
2014-01-01
The eukaryotic flagellum beats with apparently unfailing periodicity, yet responds rapidly to stimuli. Like the human heartbeat, flagellar oscillations are now known to be noisy. Using the alga \\textit{C. reinhardtii}, we explore three aspects of nonuniform flagellar beating. We report the existence of rhythmicity, waveform noise peaking at transitions between power and recovery strokes, and fluctuations of interbeat intervals that are correlated and even recurrent, with mem...
Research Methodology in Recurrent Pregnancy Loss
DEFF Research Database (Denmark)
Christiansen, Ole B
2014-01-01
The aim of this article is to highlight pitfalls in research methodology that may explain why studies in recurrent pregnancy loss (RPL) often provide very divergent results. It is hoped that insight into this issue may help clinicians decide which published studies are the most valid. It may help researchers to eliminate methodological flaws in future studies, which may hopefully come to some kind of agreement about the usefulness of diagnostic tests and treatments in RPL.
MORSE DECOMPOSITION, ATTRACTORS AND CHAIN RECURRENCE
Scientific Electronic Library Online (English)
JOSE, AYALA; PATRICK, CORBIN; KELLY, MC CONVILLE; FRITZ, COLONIUS; WOLFGANG, KLIEMANN; JUSTIN, PETERS.
2006-05-01
Full Text Available The global behavior of a dynamical system can be described by its Morse decompositions or its attractor and repeller configurations. There is a close relation between these two approaches and also with (maximal) chain recurrent sets that describe the system behavior on finest Morse sets. These sets [...] depend upper semicontinuously on parameters. The connection with ergodic theory is provided through the construction of invariant measures based on chains
MORSE DECOMPOSITION, ATTRACTORS AND CHAIN RECURRENCE
Directory of Open Access Journals (Sweden)
JOSE AYALA
2006-05-01
Full Text Available The global behavior of a dynamical system can be described by its Morse decompositions or its attractor and repeller configurations. There is a close relation between these two approaches and also with (maximal chain recurrent sets that describe the system behavior on finest Morse sets. These sets depend upper semicontinuously on parameters. The connection with ergodic theory is provided through the construction of invariant measures based on chains
Deep Recurrent Neural Networks for Acoustic Modelling
Chan, William; Lane, Ian
2015-01-01
We present a novel deep Recurrent Neural Network (RNN) model for acoustic modelling in Automatic Speech Recognition (ASR). We term our contribution as a TC-DNN-BLSTM-DNN model, the model combines a Deep Neural Network (DNN) with Time Convolution (TC), followed by a Bidirectional Long Short-Term Memory (BLSTM), and a final DNN. The first DNN acts as a feature processor to our model, the BLSTM then generates a context from the sequence acoustic signal, and the final DNN takes ...
Recurrent spontaneous intracranial hypotension in early pregnancy
McGrath, Emer; Monaghan, Thomas S; Alexander, Michael; Hennessy, Michal J
2010-01-01
Spontaneous intracranial hypotension (SIH) is an uncommon condition characterised by postural headache secondary to low cerebrospinal fluid pressure. Here we present a case of recurrence of SIH in early pregnancy in a 26-year-old woman. She first presented at the age of 21 years at 15 weeks’ gestation with a history of headache, nausea, vomiting, neck stiffness and photophobia. Findings from a MRI brain scan led to a diagnosis of SIH. She was treated with autologous epidural blood patching an...
An Unusual Cause of Recurrent Respiratory Distress
Joshi Neha
2010-01-01
A one and a half years old boy presented with recurrent episodes of respiratory distress, accompanied by dry non spasmodic cough and characterized by appearance of a continuous stridor showing no positional variation. The child was symptomatic since early infancy. Parents also complained of inability to gain weight as compared to other siblings. There was no history of foreign body ingestion or complaints of asthma or tuberculosis in the family. General physical examination revealed tachypne...
Recurrent cutaneous leishmaniasis Leishmaniose recidiva cútis
Ciro Martins Gomes; Fabiana dos Santos Damasco; Orlando Oliveira de Morais; Carmen Déa Ribeiro de Paula; Raimunda Nonata Ribeiro Sampaio
2013-01-01
We present a case of an 18-year-old male patient who, after two years of inappropriate treatment for cutaneous leishmaniasis, began to show nodules arising at the edges of the former healing scar. He was immune competent and denied any trauma. The diagnosis of recurrent cutaneous leishmaniasis was made following positive culture of aspirate samples. The patient was treated with N-methylglucamine associated with pentoxifylline for 30 days. Similar cases require special attention mainly because...
A cognitive model of recurrent nightmares
Spoormaker, Victor I.
2008-01-01
Nightmares are a prevalent mental disorder resulting in disturbed sleep, distress, and impairment in daily functioning. Elaborating on previous theoretical models for anxiety disorders, sleep disorders and dreaming, this study introduces a cognitive model of recurrent nightmares, the central element of which concerns representation of the nightmare’s repetitive storyline in the memory as a script. It is suggested that activation of this script during REM sleep results in a replay of the night...
Disease recurrence in paediatric renal transplantation
Cochat, Pierre; Fargue, Sonia; Mestrallet, Guillaume; Jungraithmayr, Therese; Koch-Nogueira, Paulo; Ranchin, Bruno; Zimmerhackl, Lothar Bernd
2009-01-01
Renal transplantation (Tx) is the treatment of choice for end-stage renal disease. The incidence of acute rejection after renal Tx has decreased because of improving early immunosuppression, but the risk of disease recurrence (DR) is becoming relatively high, with a greater prevalence in children than in adults, thereby increasing patient morbidity, graft loss (GL) and, sometimes, mortality rate. The current overall graft loss to DR is 7–8%, mainly due to primary glomerulonephritis (70–80%) a...