887 resultados para Computer forensic analysis
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The work of biochemists and molecular biologists often is dependent or extremely favored by a preliminary computer analysis. Thus, the development of an efficient and friendly computational tool is very important. In this work, we developed a package of programs in Javascript language which can be used online or locally. The programs depend exclusively of Web browsers and are compatible with Internet Explorer, Opera, Mozilla Firefox and Google Chrome. With the EBiAn package it is can perform the main analysis and manipulation of DNA, RNA, proteins and peptides sequences. The programs can be freely accessed and adapted or modified to generate new programs.
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Diottix(r) was calibrated at 25 Hz to achieve the frequency indicated in literature as being effective to mobilize the airways secretions. However, the amplitude and frequency of the waves generated by the equipment in different regions of the chest still need to be investigated. The objective of this study was to analyze the frequency and amplitude of waves generated by Diottix(r) in chests of healthy subjects. Diottix(r) was used in the anterior and posterior regions of the chest. The mechanical waves were captured using stethoscopes connected to electret microphones, which were connected to a digital oscilloscope. Frequency and amplitude data were recorded by the stethoscope, positioned in six points in the anterior region and six in the posterior region of the chest, following the positions commonly used in pulmonary auscultation. Signals were recorded and transferred to a computer with software for their analysis. The frequency of waves did not present a significant change (from 24.9 to 26.4 Hz). The wave amplitude in the anterior versus the posterior region in each area of the lung, the upper, middle and lower, had differences. Diottix(r) produces frequencies in the chest according to the calibrated; thus, it can be a complementary resource to bronchial hygiene maneuvers. The amplitudes of waves seem to be affected by other structures like bone parts and heart.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The state of insulating oils used in transformers is determined through the accomplishment of physical-chemical tests, which determine the state of the oil, as well as the chromatography test, which determines possible faults in the equipment. This article concentrate on determining, from a new methodology, a relationship among the variation of the indices obtained from the physical-chemical tests with those indices supplied by the chromatography tests.The determination of the relationship among the tests is accomplished through the application of neural networks. From the data obtained by physical-chemical tests, the network is capable to determine the relationship among the concentration of the main gases present in a certain sample, which were detected by the chromatography tests.More specifically, the proposed approach uses neural networks of perceptron type constituted of multiple layers. After the process of network training, it is possible to determine the existent relationship between the physical-chemical tests and the amount of gases present in the insulating oil.
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Results of the analysis of dynamic behavior of flashover phenomenon on the high voltage-polluted insulators are presented. These results were taken from a mathematical and an experimental model that introduce the variable thickness influence of the layer pollution deposited on the high-voltage insulator surface. Analysis of the flashover was done by way of introducing a variation in the thickness of the channel of Obenaus' model, simulating a layer pollution of variable thickness. The objective was to obtain a better reproduction of the real layer pollution deposited on the insulator that works in the polluted regions. Two types of thickness variations were used: a sudden variation, using a step; and a soft variation, using a ramp; that were put along the way of the discharge. Comparison between the mathematical and experimental models showed that introduction of a ramp makes Obenaus' model more efficient in analyzing behavior of flashover phenomenon.
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Veneer fracture is the most common complication in zirconia-based restorations. The aim of this study was to evaluate the mechanical behavior of a zirconia-based crown in a lower canine tooth supporting removable partial denture (RPD) prosthesis, varying the bond quality of the veneer/coping interface. Microtomography (μCT) data of an extracted left lower canine were used to build the finite element model (M) varying the core material (gold core - MAu; zirconia core - MZi) and the quality of the veneer/core interface (complete bonded - MZi; incomplete bonded - MZi-NL). The incomplete bonding condition was only applied for zirconia coping by using contact elements (Target/Contact) with 0.3 frictional coefficients. Stress fields were obtained using Ansys Workbench 10.0. The loading condition (L = 1 N) was vertically applied at the base of the RPD prosthesis metallic support towards the dental apex. Maximum principal (σmax) and von Mises equivalent (σvM) stresses were obtained. The σmax (MPa) for the bonded condition was similar between gold and zirconia cores (MAu, 0.42; MZi, 0.40). The incomplete bonded condition (MZi-NL) raised σmax in the veneer up to 800% (3.23 MPa) in contrast to the bonded condition. The peak of σvM increased up to 270% in the MZi-NL. The incomplete bond condition increasing the stress in the veneer/zirconia interface.
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Synthacaine is a New Psychoactive Substance which is, due to its inherent psychoactive properties, reported to imitate the effects of cocaine and is therefore consequently branded as legal cocaine. The only analytical approach reported to date for the sensing of Synthacaine is mass spectrometry. In this paper, we explore and evaluate a range of potential analytical techniques for its quantification and potential use in the field screening Synthacaine using Raman spectroscopy, presumptive (colour) testing, High Performance Liquid Chromatography (HPLC) and electrochemistry. HPLC analysis of street samples reveals that Synthacaine comprises a mixture of methiopropamine (MPA) and 2-aminoindane (2-AI). Raman spectroscopy and presumptive (colour) tests, the Marquis, Mandelin, Simon's and Robadope test, are evaluated towards a potential in-the-field screening approach but are found to not be able to discriminate between the two when they are both present in the same sample, as is the case in the real street samples. We report for the first time a novel indirect electrochemical protocol for the sensing of MPA and 2-AI which is independently validated in street samples with HPLC. This novel electrochemical approach based upon one-shot disposable cost effective screen-printed graphite macroelectrodes holds potential for in-the-field screening for Synthacaine.
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This paper deals with transient stability analysis based on time domain simulation on vector processing. This approach requires the solution of a set of differential equations in conjunction of another set of algebraic equations. The solution of the algebraic equations has presented a scalar as sequential set of tasks, and the solution of these equations, on vector computers, has required much more investigations to speedup the simulations. Therefore, the main objective of this paper has been to present methods to solve the algebraic equations using vector processing. The results, using a GRAY computer, have shown that on-line transient stability assessment is feasible.
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Sparse traffic grooming is a practical problem to be addressed in heterogeneous multi-vendor optical WDM networks where only some of the optical cross-connects (OXCs) have grooming capabilities. Such a network is called as a sparse grooming network. The sparse grooming problem under dynamic traffic in optical WDM mesh networks is a relatively unexplored problem. In this work, we propose the maximize-lightpath-sharing multi-hop (MLS-MH) grooming algorithm to support dynamic traffic grooming in sparse grooming networks. We also present an analytical model to evaluate the blocking performance of the MLS-MH algorithm. Simulation results show that MLSMH outperforms an existing grooming algorithm, the shortest path single-hop (SPSH) algorithm. The numerical results from analysis show that it matches closely with the simulation. The effect of the number of grooming nodes in the network on the blocking performance is also analyzed.
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Static analysis tools report software defects that may or may not be detected by other verification methods. Two challenges complicating the adoption of these tools are spurious false positive warnings and legitimate warnings that are not acted on. This paper reports automated support to help address these challenges using logistic regression models that predict the foregoing types of warnings from signals in the warnings and implicated code. Because examining many potential signaling factors in large software development settings can be expensive, we use a screening methodology to quickly discard factors with low predictive power and cost-effectively build predictive models. Our empirical evaluation indicates that these models can achieve high accuracy in predicting accurate and actionable static analysis warnings, and suggests that the models are competitive with alternative models built without screening.
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Not long ago, most software was written by professional programmers, who could be presumed to have an interest in software engineering methodologies and in tools and techniques for improving software dependability. Today, however, a great deal of software is written not by professionals but by end-users, who create applications such as multimedia simulations, dynamic web pages, and spreadsheets. Applications such as these are often used to guide important decisions or aid in important tasks, and it is important that they be sufficiently dependable, but evidence shows that they frequently are not. For example, studies have shown that a large percentage of the spreadsheets created by end-users contain faults. Despite such evidence, until recently, relatively little research had been done to help end-users create more dependable software. We have been working to address this problem by finding ways to provide at least some of the benefits of formal software engineering techniques to end-user programmers. In this talk, focusing on the spreadsheet application paradigm, I present several of our approaches, focusing on methodologies that utilize source-code-analysis techniques to help end-users build more dependable spreadsheets. Behind the scenes, our methodologies use static analyses such as dataflow analysis and slicing, together with dynamic analyses such as execution monitoring, to support user tasks such as validation and fault localization. I show how, to accommodate the user base of spreadsheet languages, an interface to these methodologies can be provided in a manner that does not require an understanding of the theory behind the analyses, yet supports the interactive, incremental process by which spreadsheets are created. Finally, I present empirical results gathered in the use of our methodologies that highlight several costs and benefits trade-offs, and many opportunities for future work.
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The elimination of all external incisions is an important step in reducing the invasiveness of surgical procedures. Natural Orifice Translumenal Endoscopic Surgery (NOTES) is an incision-less surgery and provides explicit benefits such as reducing patient trauma and shortening recovery time. However, technological difficulties impede the widespread utilization of the NOTES method. A novel robotic tool has been developed, which makes NOTES procedures feasible by using multiple interchangeable tool tips. The robotic tool has the capability of entering the body cavity through an orifice or a single incision using a flexible articulated positioning mechanism and once inserted is not constrained by incisions, allowing for visualization and manipulations throughout the cavity. Multiple interchangeable tool tips of the robotic device initially consist of three end effectors: a grasper, scissors, and an atraumatic Babcock clamp. The tool changer is capable of selecting and switching between the three tools depending on the surgical task using a miniature mechanism driven by micro-motors. The robotic tool is remotely controlled through a joystick and computer interface. In this thesis, the following aspects of this robotic tool will be detailed. The first-generation robot is designed as a conceptual model for implementing a novel mechanism of switching, advancing, and controlling the tool tips using two micro-motors. It is believed that this mechanism achieves a reduction in cumbersome instrument exchanges and can reduce overall procedure time and the risk of inadvertent tissue trauma during exchanges with a natural orifice approach. Also, placing actuators directly at the surgical site enables the robot to generate sufficient force to operate effectively. Mounting the multifunctional robot on the distal end of an articulating tube provides freedom from restriction on the robot kinematics and helps solve some of the difficulties otherwise faced during surgery using NOTES or related approaches. The second-generation multifunctional robot is then introduced in which the overall size is reduced and two arms provide 2 additional degrees of freedom, resulting in feasibility of insertion through the esophagus and increased dexterity. Improvements are necessary in future iterations of the multifunctional robot; however, the work presented is a proof of concept for NOTES robots capable of abdominal surgical interventions.
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Overhead distribution lines are often exposed to lightning overvoltages, whose waveforms vary widely and can differ substantially from the standard impulse voltage waveform (1,2 - 50). Different models have been proposed for predicting the strength of insulation subjected to impulses of non-standard waveforms. One of the most commonly used is the disruptive effect model, for which there are different methods for the estimation of the parameters required for its application. This paper aims at evaluating the dielectric behavior of medium voltage insulators subjected to impulses of non-standard waveforms, as well as at evaluating two methods for predicting their dielectric strength against such impulses. The test results relative to the critical lightning impulse flashover voltage (U50) and the volt-time characteristics obtained for the positive and negative polarities of different voltage waveforms are presented and discussed.
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Color texture classification is an important step in image segmentation and recognition. The color information is especially important in textures of natural scenes, such as leaves surfaces, terrains models, etc. In this paper, we propose a novel approach based on the fractal dimension for color texture analysis. The proposed approach investigates the complexity in R, G and B color channels to characterize a texture sample. We also propose to study all channels in combination, taking into consideration the correlations between them. Both these approaches use the volumetric version of the Bouligand-Minkowski Fractal Dimension method. The results show a advantage of the proposed method over other color texture analysis methods. (C) 2011 Elsevier Ltd. All rights reserved.