Análise de formas planas em imagens digitais: uma nova abordagem baseada na Transformada de Hough

Pós-graduação em Ciência da Computação - IBILCE

Fractal analysis of leaf-texture properties as a tool for taxonomic and identification purposes: a case study with species from Neotropical Melastomataceae (Miconieae tribe)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

An Intelligent System for Petroleum Well Drilling Cutting Analysis

Cutting analysis is a important and crucial task task to detect and prevent problems during the petroleum well drilling process. Several studies have been developed for drilling inspection, but none of them takes care about analysing the generated cutting at the vibrating shale shakers. Here we proposed a system to analyse the cutting's concentration at the vibrating shale shakers, which can indicate problems during the petroleum well drilling process, such that the collapse of the well borehole walls. Cutting's images are acquired and sent to the data analysis module, which has as the main goal to extract features and to classify frames according to one of three previously classes of cutting's volume. A collection of supervised classifiers were applied in order to allow comparisons about their accuracy and efficiency. We used the Optimum-Path Forest (OPF), Artificial Neural Network using Multi layer Perceptrons (ANN-MLP), Support Vector Machines (SVM) and a Bayesian Classifier (BC) for this task. The first one outperformed all the remaining classifiers. Recall that we are also the first to introduce the OPF classifier in this field of knowledge. Very good results show the robustness of the proposed system, which can be also integrated with other commonly system (Mud-Logging) in order to improve the last one's efficiency.

Brazilian Students and Working Capital: An Analysis of Their Decisions When Using Virtual Market Business Games

This study aims to demonstrate that data from business games can be an important resource for improving efficiency and effectiveness of learning. The proposal presented here was developed from preliminary studies of data from Virtual Market games that pointed the possibility of identifying gaps in learning by analyzing the decisions of students. This proposal helps students to refine their learning processes and equips tutors with strategies for teaching and student assessment. The proposal also complements the group discussion and/or debriefing, which are widely used to enhance learning mediated by games. However, from a management perspective the model has the potential to be erroneous and miss opportunities, which cannot be detected because of the dependence on the characteristics of the individual, such as ability to communicate and work together. To illustrate the proposed technique, data sets from two business games were analyzed with the focus on managing working capital and it was found that students had difficulties managing this task. Similar trends were observed in all categories of students in the study-undergraduate, postgraduate and specialization. This discovery led us to the analysis of data for decisions made in the performance of the games, and it was determined that indicators could be developed that were capable of indentifying inconsistencies in the decisions. It was decided to apply some basic concepts of the finance management, such as management of the operational and non-operational expenditures, as well as production management concepts, such as the use of the production capacity. By analyzing the data from the Virtual Market games using the indicator concept, it was possible to detect the lack of domain knowledge of the students. Therefore, these indicators can be used to analyze the decisions of the players and guide them during the game, increasing their effectiveness and efficiency. As these indicators were developed from specific content, they can also be used to develop teaching materials to support learning. Viewed in this light, the proposal adds new possibilities for using business games in learning. In addition to the intrinsic learning that is achieved through playing the games, they also assist in driving the learning process. This study considers the applications and the methodology used.

Analysis of speech fluency in Williams syndrome

Williams syndrome (WS) is a neurodevelopmental genetic disorder, often referred as being characterized by dissociation between verbal and non-verbal abilities, although the number of studies disputing this proposal is emerging. Indeed, although they have been traditionally reported as displaying increased speech fluency, this topic has not been fully addressed in research. In previous studies carried out with a small group of individuals with WS, we reported speech breakdowns during conversational and autobiographical narratives suggestive of language difficulties. In the current study, we characterized the speech fluency profile using an ecologically based measure - a narrative task (story generation) was collected from a group of individuals with WS (n = 30) and typically developing group (n = 39) matched in mental age. Oral narratives were elicited using a picture stimulus - the cookie theft picture from Boston Diagnosis Aphasia Test. All narratives were analyzed according to typology and frequency of fluency breakdowns (non-stuttered and stuttered disfluencies). Oral narratives in WS group differed from typically developing group, mainly due to a significant increase in the frequency of disfluencies, particularly in terms of hesitations, repetitions and pauses. This is the first evidence of disfluencies in WS using an ecologically based task (oral narrative task), suggesting that these speech disfluencies may represent a significant marker of language problems in WS. (C) 2011 Elsevier Ltd. All rights reserved.

Spectral analysis of the electromyograph of the erector spinae muscle before and after a dynamic manual load-lifting test

The aim of the present study was to assess the spectral behavior of the erector spinae muscle during isometric contractions performed before and after a dynamic manual load-lifting test carried out by the trunk in order to determine the capacity of muscle to perform this task. Nine healthy female students participated in the experiment. Their average age, height, and body mass (± SD) were 20 ± 1 years, 1.6 ± 0.03 m, and 53 ± 4 kg, respectively. The development of muscle fatigue was assessed by spectral analysis (median frequency) and root mean square with time. The test consisted of repeated bending movements from the trunk, starting from a 45º angle of flexion, with the application of approximately 15, 25 and 50% of maximum individual load, to the stand up position. The protocol used proved to be more reliable with loads exceeding 50% of the maximum for the identification of muscle fatigue by electromyography as a function of time. Most of the volunteers showed an increase in root mean square versus time on both the right (N = 7) and the left (N = 6) side, indicating a tendency to become fatigued. With respect to the changes in median frequency of the electromyographic signal, the loads used in this study had no significant effect on either the right or the left side of the erector spinae muscle at this frequency, suggesting that a higher amount and percentage of loads would produce more substantial results in the study of isotonic contractions.

Screening Brazilian commercial gasoline quality by hydrogen nuclear magnetic resonance spectroscopic fingerprintings and pattern-recognition multivariate chemometric analysis

The identification of gasoline adulteration by organic solvents is not an easy task, because compounds that constitute the solvents are already in gasoline composition. In this work, the combination of Hydrogen Nuclear Magnetic Resonance ((1)H NMR) spectroscopic fingerprintings with pattern-recognition multivariate Soft Independent Modeling of Class Analogy (SIMCA) chemometric analysis provides an original and alternative approach to screening Brazilian commercial gasoline quality in a Monitoring Program for Quality Control of Automotive Fuels. SIMCA was performed on spectroscopic fingerprints to classify the quality of representative commercial gasoline samples selected by Hierarchical Cluster Analysis (HCA) and collected over a 6-month period from different gas stations in the São Paulo state, Brazil. Following optimized the (1)H NMR-SIMCA algorithm, it was possible to correctly classify 92.0% of commercial gasoline samples, which is considered acceptable. The chemometric method is recommended for routine applications in Quality-Control Monitoring Programs, since its measurements are fast and can be easily automated. Also, police laboratories could employ this method for rapid screening analysis to discourage adulteration practices. (C) 2010 Elsevier B.V. All rights reserved.

The application of interpolating MLS approximations to the analysis of MHD flows

The element-free Galerkin method (EFGM) is a very attractive technique for solutions of partial differential equations, since it makes use of nodal point configurations which do not require a mesh. Therefore, it differs from FEM-like approaches by avoiding the need of meshing, a very demanding task for complicated geometry problems. However, the imposition of boundary conditions is not straightforward, since the EFGM is based on moving-least-squares (MLS) approximations which are not necessarily interpolants. This feature requires, for instance, the introduction of modified functionals with additional unknown parameters such as Lagrange multipliers, a serious drawback which leads to poor conditionings of the matrix equations. In this paper, an interpolatory formulation for MLS approximants is presented: it allows the direct introduction of boundary conditions, reducing the processing time and improving the condition numbers. The formulation is applied to the study of two-dimensional magnetohydrodynamic flow problems, and the computed results confirm the accuracy and correctness of the proposed formulation. (C) 2002 Elsevier B.V. All rights reserved.

The influence of visual stimuli in ethnobotanical data collection using the listing task method

The listing task, a method used in social and behavioral sciences, is frequently used in ethnobotanical research to constructfolk taxonomies and select relevant itemsfor subsequent research. The objective of the present study was to determine whether visual stimuli are associated with responses to the theme plants or if context influences the answers. Interviews were conducted with 400 women in Rio Claro, São Paulo, Brazil, in four different locations: three with a visible presence of plants (a plant store, a supermarket, and a public plaza) and one with no plants (a street corner in the center of the city). The women were asked to name plants. Analysis indicates that visual stimuli influenced responses and that this is more marked in the plant store than in the other locations. The plants cited most often-roses, orchids, ferns, violets, and daisies-were, with little variation, the same in all the locales studied.

Electromyographic analysis of the rectus abdominis muscle in pelvic retroversion and the decrease of the lower limbs

We often face Patients searching for rehabilitation for lower back disorders during the physiotherapeutic routine, and it is known that the abdominal muscle, specially the rectus abdominis muscle, aid the stabilization of the pelvis. Therefore, this paper analyzes the electrical activity of the rectus abdominis muscle in the pelvic retroversion in dorsal decubitus and in orthostatic position and in the lowering of the lower limbs. 30 healthy students, male and female, 17-40 yr, divided into two groups - Group 1: 15 volunteers (pelvic balance); Group 2 (pelvic unbalance) took part in this study. The electrical activity of the right and left supra-umbilical and infra-umbilical portions of the rectus abdominis muscle was detected. The mean RMS values from three attempts ftom the electromyographic traces were usedfor the analysis of the electrical activity. The RMS value was submitted to the normalization process. The data were submitted to statistic treatment by the Friedman test, and the analyses of the means and standard deviation towards a level of significance of 95%. The results demonstrated that the portions of the rectus abdominis muscle presented low electrical activity for the groups studiedfor pelvic retroversion either in dorsal decubitus or and orthostatic position. However, the decreasing movement of the lower limbs towards the portions of the rectus abdominis muscle presented more significant electrical activity whereas the lower portions presented higher activity than the higher ones for Group 2.

The influence of the flexibility of the chair seat on pressure peak and distribution of the contact area in individuals with cerebral palsy during the execution of a task

This study aimed to determine the influence of flexibility of the chair seat surface on the pressure peak and on the contact area during the execution of a task of handling an object on the seated position by individuals with spastic cerebral palsy. Ten individuals of both genders with diagnosis of spastic cerebral palsy, who had some control to voluntarily move the body and the upper limbs, participated in this study. Quantification of data was carried out in two experimental situations: (1) execution of a task of fitting with upper limbs, and with the individual placed on an adapted canvas seat; (2) execution of a task of fitting with the participant positioned on an adapted wooden seat. Data obtained were submitted to a non-parametric and descriptive statistical analysis using the Wilcoxon test. Results indicated that the use of canvas seat increased the contact area and decreased the pressure peak and the medio-lateral displacement of centre pressure on the seated posture. © 2011 Informa UK, Ltd.

Grip and load force coordination in cyclical isometric manipulation task is not affected by the feedback type

Background: The relationship between normal and tangential force components (grip force - GF and load force - LF, respectively) acting on the digits-object interface during object manipulation reveals neural mechanisms involved in movement control. Here, we examined whether the feedback type provided to the participants during exertion of LF would influence GF-LF coordination and task performance. Methods. Sixteen young (24.7 ±3.8 years-old) volunteers isometrically exerted continuously sinusoidal FZ (vertical component of LF) by pulling a fixed instrumented handle up and relaxing under two feedback conditions: targeting and tracking. In targeting condition, FZ exertion range was determined by horizontal lines representing the upper (10 N) and lower (1 N) targets, with frequency (0.77 or 1.53 Hz) dictated by a metronome. In tracking condition, a sinusoidal template set at similar frequencies and range was presented and should be superposed by the participants' exerted FZ. Task performance was assessed by absolute errors at peaks (AEPeak) and valleys (AEValley) and GF-LF coordination by GF-LF ratios, maximum cross-correlation coefficients (r max), and time lags. Results: The results revealed no effect of feedback and no feedback by frequency interaction on any variable. AE Peak and GF-LF ratio were higher and rmax lower at 1.53 Hz than at 0.77 Hz. Conclusion: These findings indicate that the type of feedback does not influence task performance and GF-LF coordination. Therefore, we recommend the use of tracking tasks when assessing GF-LF coordination during isometric LF exertion in externally fixed instrumented handles because they are easier to understand and provide additional indices (e.g., RMSE) of voluntary force control. © 2013 Pedão et al.; licensee BioMed Central Ltd.

Performance of Down syndrome subjects during a coincident timing task

Background: The time synchronization is a very important ability for the acquisition and performance of motor skills that generate the need to adapt the actions of body segments to external events of the environment that are changing their position in space. Down Syndrome (DS) individuals may present some deficits to perform tasks with synchronization demand. We aimed to investigate the performance of individuals with DS in a simple Coincident Timing task. Method. 32 individuals were divided into 2 groups: the Down syndrome group (DSG) comprised of 16 individuals with average age of 20 (+/- 5 years old), and a control group (CG) comprised of 16 individuals of the same age. All individuals performed the Simple Timing (ST) task and their performance was measured in milliseconds. The study was conducted in a single phase with the execution of 20 consecutive trials for each participant. Results: There was a significant difference in the intergroup analysis for the accuracy adjustment - Absolute Error (Z = 3.656, p = 0.001); and for the performance consistence - Variable Error (Z = 2.939, p = 0.003). Conclusion: DS individuals have more difficulty in integrating the motor action to an external stimulus and they also present more inconsistence in performance. Both groups presented the same tendency to delay their motor responses. © 2013 Torriani-Pasin et al.; licensee BioMed Central Ltd.

Separation of Scaptotrigona postica Workers into Defined Task Groups by the Chemical Profile on Their Epicuticle Wax Layer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Stabilometric parameters analysis in children with visual disorder

Background: Although postural changes were already reported in blind adults, no previous study has investigated postural stability in blind children. Moreover, there are few studies which used a stabilometric instrument to measure postural balance. In this study we evaluated stabilometric paramaters in blind children. Methods: We evaluated children between 7 to 12 years old, they were divided into two groups: Blind (n = 11) and age-matched control (n = 11) groups by using computerized stabilometry. The stabilometric examination was performed taking the gravity centers displacement of the individual projected into the platform. Thirthy seconds after the period in which this information was collected, the program defined a medium-pressure center, which was used to define x and y axes displacement and the distance between the pressure center and the platform center. Furthermore, the average sway rate and the body sway area were obtained by dividing the pressure center displacement and the time spent on the task; and by an ellipse function (95% percentille), respectively. Percentages of anterior, posterior, left and right feet weight also were calculated. Variables were compared by using the Student’s t test for unpaired data. Significance level was considered for p <0.05. Results: Displacement of the x axis (25.55 ± 9.851 vs. -3.545 ± 7.667; p <0.05) and average sway rate (19.18 ± 2.7 vs. -10.55 ± 1.003; p <0.001) were increased in the blind children group. Percentage of left foot weight was reduced (45.82 ± 2.017 vs. 52.36 ± 1.33; p <0.05) while percentage of right foot weight was increased (54.18 ± 2.17 vs. 47.64 ± 1.33; p <0.05) in blind children. Other variables did not show differences. Conclusions: Blind children present impaired stabilometric parameters.