667 research outputs found
Face Recognition Methods Based on Feedforward Neural Networks, Principal Component Analysis and Self-Organizing Map
In this contribution, human face as biometric is considered. Original method of feature extraction from image data is introduced using MLP (multilayer perceptron) and PCA (principal component analysis). This method is used in human face recognition system and results are compared to face recognition system using PCA directly, to a system with direct classification of input images by MLP and RBF (radial basis function) networks, and to a system using MLP as a feature extractor and MLP and RBF networks in the role of classifier. Also a two-stage method for face recognition is presented, in which Kohonen self-organizing map is used as a feature extractor. MLP and RBF network are used as classifiers. In order to obtain deeper insight into presented methods, also visualizations of internal representation of input data obtained by neural networks are presented
Error Concealment using Neural Networks for Block-Based Image Coding
In this paper, a novel adaptive error concealment (EC) algorithm, which lowers the requirements for channel coding, is proposed. It conceals errors in block-based image coding systems by using neural network. In this proposed algorithm, only the intra-frame information is used for reconstruction of the image with separated damaged blocks. The information of pixels surrounding a damaged block is used to recover the errors using the neural network models. Computer simulation results show that the visual quality and the MSE evaluation of a reconstructed image are significantly improved using the proposed EC algorithm. We propose also a simple non-neural approach for comparison
A Comparison Between The NORCAT Rover Test Results and the ISRU Excavation System Model Predictions Results
An Excavation System Model has been written to simulate the collection and transportation of regolith on the moon. The calculations in this model include an estimation of the forces on the digging tool as a result of excavation into the regolith. Verification testing has been performed and the forces recorded from this testing were compared to the calculated theoretical data. The Northern Centre for Advanced Technology Inc. rovers were tested at the NASA Glenn Research Center Simulated Lunar Operations facility. This testing was in support of the In-Situ Resource Utilization program Innovative Partnership Program. Testing occurred in soils developed at the Glenn Research Center which are a mixture of different types of sands and whose soil properties have been well characterized. This testing is part of an ongoing correlation of actual field test data to the blade forces calculated by the Excavation System Model. The results from this series of tests compared reasonably with the predicted values from the code
Asymmetric Image Encryption Approach with Plaintext-Related Diffusion
This paper deals with topic of image encryption based on chaotic maps. A solution which has advantage of robustness against chosen-plaintext attacks is proposed. Permutations of image pixels are carried out in a way that enables operations on grayscale images with arbitrary resolution. All calculations done with user key and also all diffusion processes employ the same chaotic map. This feature enables usage of look-up tables which reduce computational times. The paper includes several experiments which verify achieved results and also briefly describes advantages and drawbacks of proposed solution
An Open Virtual Neighbourhood Network to Connect IoT Infrastructures and Smart Objects – VICINITY:IoT enables interoperability as a service
Similar local, but different systemic, metabolomic responses of closely related pine subspecies to folivory by caterpillars of the processionary moth
ABSTRACT Plants respond locally and systemically to herbivore attack. Most of the research conducted on plant-herbivore relationships at element and molecular levels have focused on the elemental composition or/and certain molecular compounds or specific families of defence metabolites showing that herbivores tend to select plant individuals or species with higher nutrient concentrations and avoid those with higher levels of defence compounds. We performed stoichiometric and metabolomics, both local and systemic, analyses in two subspecies of Pinus sylvestris under attack from caterpillars of the pine processionary moth, an important pest in the Mediterranean Basin. Both pine subspecies responded locally to folivory mainly by increasing relative concentrations of terpenes and some phenolics. Systemic responses differed between pine subspecies, and most of the metabolites presented intermediate concentrations between those of the affected parts and unattacked trees. Our results support the hypothesis that foliar nutrient concentrations are not a key factor for plant selection by adult female processionary moths for oviposition, since folivory was not associated with any of the elements analysed. Phenolic compounds generally did not increase in the attacked trees, questioning the suggestion of induction of phenolics following folivory attack and the anti-feeding properties of phenolics. Herbivory attack produced a general systemic shift in pines, in both primary and secondary metabolism, which was less intense and chemically different from the local responses. Local pine responses were similar between pine subspecies, while systemic responses were more distant
Similar local, but different systemic, metabolomic responses of closely related pine subspecies to folivory by caterpillars of the processionary moth
ABSTRACT Plants respond locally and systemically to herbivore attack. Most of the research conducted on plant-herbivore relationships at element and molecular levels have focused on the elemental composition or/and certain molecular compounds or specific families of defence metabolites showing that herbivores tend to select plant individuals or species with higher nutrient concentrations and avoid those with higher levels of defence compounds. We performed stoichiometric and metabolomics, both local and systemic, analyses in two subspecies of Pinus sylvestris under attack from caterpillars of the pine processionary moth, an important pest in the Mediterranean Basin. Both pine subspecies responded locally to folivory mainly by increasing relative concentrations of terpenes and some phenolics. Systemic responses differed between pine subspecies, and most of the metabolites presented intermediate concentrations between those of the affected parts and unattacked trees. Our results support the hypothesis that foliar nutrient concentrations are not a key factor for plant selection by adult female processionary moths for oviposition, since folivory was not associated with any of the elements analysed. Phenolic compounds generally did not increase in the attacked trees, questioning the suggestion of induction of phenolics following folivory attack and the anti-feeding properties of phenolics. Herbivory attack produced a general systemic shift in pines, in both primary and secondary metabolism, which was less intense and chemically different from the local responses. Local pine responses were similar between pine subspecies, while systemic responses were more distant
Predictors of Citations in Neurosurgical Research: A 5-year Follow-Up
Introduction
Citation rates are an important measure for the impact of publications. This study is the most comprehensive analysis of predictors for scientific neurosurgical research articles.
Methods
Scientific articles published in 13 neurosurgical journals in 2015 were selected. Data collected included: article subject, level of evidence (LOE), journal impact factor (IF), authorship, contributing centers, and study design. Citation counts were collected for each article in the Web of Science (WoS), Google Scholar (GS), and Scopus 2.5 and 5 years after publication. A generalized linear mixed effects model using the predictors of search engine, LOE, number of centers, number of authors, and IF was constructed to predict total citation count at 5 years.
Results
2867 articles generated 39190 citations in WoS, 61682 in GS, and 43481 in Scopus. The median [interquartile range] number of citations per article was 10 [14] in WoS, 15 [20] in GS, and 11 [15] in Scopus. On average, for every 1 citation in WoS, Scopus and GS identified 1.11 and 1.58 citations, respectively. Significant predictors of citation count in all databases 5 years after publication included search engine, LOE, number of centers, number of authors, number of countries, journal IF, and the month of publication (p<0.05). The article subject (tumor, spine, etc.) did not significantly predict citation counts.
Conclusions
In the most thorough analysis of citation predictors in the neurosurgical literature, search engine, LOE, number of centers, number of authors, number of countries, journal impact factor, and month of publication influenced citations 5 years after publication
Plasma proteome changes in cardiovascular disease patients: novel isoforms of apolipoprotein A1
<p>Abstract</p> <p>Background</p> <p>The aim of this proteomic study was to look for changes taking place in plasma proteomes of patients with acute myocardial infarction (AMI), unstable angina pectoris (UAP), and stable angina pectoris (SAP).</p> <p>Methods</p> <p>Depleted plasma proteins were separated by 2D SDS-PAGE (pI 4-7), and proteomes were compared using Progenesis SameSpots statistical software. Proteins were identified by nanoLC-MS/MS. Proteins were quantified using commercial kits. Apolipoprotein A1 was studied using 1D and 2D SDS-PAGE, together with western blotting.</p> <p>Results</p> <p>Reciprocal comparison revealed 46 unique, significantly different spots; proteins in 34 spots were successfully identified and corresponded to 38 different proteins. Discrete comparisons of patient groups showed 45, 41, and 8 significantly different spots when AMI, UAP, and SAP were compared with the control group. On the basis of our proteomic data, plasma levels of two of them, alpha-1 microglobulin and vitamin D-binding protein, were determined. The data, however, failed to prove the proteins to be suitable markers or risk factors in the studied groups. The plasma level and isoform representation of apolipoprotein A1 were also estimated. Using 1D and 2D SDS-PAGE, together with western blotting, we observed extra high-molecular weight apolipoprotein A1 fractions presented only in the patient groups, indicating that the novel high-molecular weight isoforms of apolipoprotein A1 may be potential new markers or possible risk factors of cardiovascular disease.</p> <p>Conclusion</p> <p>The reported data show plasma proteome changes in patients with AMI, UAP, and SAP. We propose some apolipoprotein A1 fractions as a possible new disease-associated marker of cardiovascular disorders.</p
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