Search results for: Alexandre Hassanin
78 Molecular Evidence for Three Species of Giraffa
Authors: Alice Petzold, Alexandre Hassanin
Abstract:
The number of giraffe species has been in focus of interest since the exploration of sub-Saharan Africa by European naturalists during the 18th and 19th centuries, as previous taxonomists, like Geoffroy Saint-Hilaire, Richard Owen or William Edward de Winton, recognized two or three species of Giraffa. For the last decades, giraffes were commonly considered as a single species subdivided into nine subspecies. In this study, we have re-examined available nuclear and mitochondrial data. Our genetic admixture analyses of seven introns support three species: G. camelopardalis (i.e., northern giraffes including reticulated giraffes), G. giraffa (southern giraffe) and G. tippelskirchi (Masai giraffe). However, the nuclear alignments show small variation and our phylogenetic analyses provide high support only for the monophyly of G. camelopardalis. Comparisons with the mitochondrial tree revealed a robust conflict for the position and monophyly of G. giraffa and G. tippelskirchi, which is explained firstly by a mitochondrial introgression from Masai giraffe to southeastern giraffe, and secondly, by gene flow mediated by male dispersal between southern populations (subspecies angolensis and giraffa). We conclude that current data gives only moderate support for three giraffe species and point out that additional nuclear data need to be studied to revise giraffe taxonomy.Keywords: autosomal markers, Giraffidae, mitochondrial introgression, taxonomy
Procedia PDF Downloads 19377 Identification of Promising Infant Clusters to Obtain Improved Block Layout Designs
Authors: Mustahsan Mir, Ahmed Hassanin, Mohammed A. Al-Saleh
Abstract:
The layout optimization of building blocks of unequal areas has applications in many disciplines including VLSI floorplanning, macrocell placement, unequal-area facilities layout optimization, and plant or machine layout design. A number of heuristics and some analytical and hybrid techniques have been published to solve this problem. This paper presents an efficient high-quality building-block layout design technique especially suited for solving large-size problems. The higher efficiency and improved quality of optimized solutions are made possible by introducing the concept of Promising Infant Clusters in a constructive placement procedure. The results presented in the paper demonstrate the improved performance of the presented technique for benchmark problems in comparison with published heuristic, analytic, and hybrid techniques.Keywords: block layout problem, building-block layout design, CAD, optimization, search techniques
Procedia PDF Downloads 37876 A Model for Operating Rooms Scheduling
Authors: Jose Francisco Ferreira Ribeiro, Alexandre Bevilacqua Leoneti, Andre Lucirton Costa
Abstract:
This paper presents a mathematical model in binary variables 0/1 to make the assignment of surgical procedures to the operating rooms in a hospital. The proposed mathematical model is based on the generalized assignment problem, which maximizes the sum of preferences for the use of the operating rooms by doctors, respecting the time available in each room. The corresponding program was written in Visual Basic of Microsoft Excel, and tested to schedule surgeries at St. Lydia Hospital in Ribeirao Preto, Brazil.Keywords: generalized assignment problem, logistics, optimization, scheduling
Procedia PDF Downloads 28375 Templating Copper on Polymer/DNA Hybrid Nanowires
Authors: Mahdi Almaky, Reda Hassanin, Benjamin Horrocks, Andrew Houlton
Abstract:
DNA-templated poly(N-substituted pyrrole)bipyridinium nanowires were synthesised at room temperature using the chemical oxidation method. The resulting CPs/DNA hybrids have been characterised using electronic and vibrational spectroscopic methods especially Ultraviolet-Visible (UV-Vis) spectroscopy and FTIR spectroscpy. The nanowires morphology was characterised using Atomic Force Microscopy (AFM). The electrical properties of the prepared nanowires were characterised using Electrostatic Force Microscopy (EFM), and measured using conductive AFM (c-AFM) and two terminal I/V technique, where the temperature dependence of the conductivity was probed. The conductivities of the prepared CPs/DNA nanowires are generally lower than PPy/DNA nanowires showingthe large effect on N-alkylation in decreasing the conductivity of the polymer, butthese are higher than the conductivity of their corresponding bulk films.This enhancement in conductivity could be attributed to the ordering of the polymer chains on DNA during the templating process. The prepared CPs/DNA nanowires were used as templates for the growth of copper nanowires at room temperature using aqueous solution of Cu(NO3)2as a source of Cu2+ and ascorbic acid as reducing agent. AFM images showed that these nanowires were uniform and continuous compared to copper nanowires prepared using the templating method directly onto DNA. Electrical characterization of the nanowires by c AFM revealed slight improvement in conductivity of these nanowires (Cu-CPs/DNA) compared to CPs/DNA nanowires before metallisation.Keywords: templating, copper nanowires, polymer/DNA hybrid, chemical oxidation method
Procedia PDF Downloads 35574 A Quadcopter Stability Analysis: A Case Study Using Simulation
Authors: C. S. Bianca Sabrina, N. Egidio Raimundo, L. Alexandre Baratella, C. H. João Paulo
Abstract:
This paper aims to present a study, with the theoretical concepts and applications of the Quadcopter, using the MATLAB simulator. In order to use this tool, the study of the stability of the drone through a Proportional - Integral - Derivative (PID) controller will be presented. After the stability study, some tests are done on the simulator and its results will be presented. From the mathematical model, it is possible to find the Newton-Euler angles, so that it is possible to stabilize the quadcopter in a certain position in the air, starting from the ground. In order to understand the impact of the controllers gain values on the stabilization of the Euler-Newton angles, three conditions will be tested with different controller gain values.Keywords: controllers, drones, quadcopter, stability
Procedia PDF Downloads 19473 Changing Trends in the Use of Induction Agents for General Anesthesia for Cesarean Section
Authors: Mahmoud Hassanin, Amita Gupta
Abstract:
Background: During current practice, Thiopentone is not cost-effectively added to resources wastage, risk of drug error with antibiotics, short shelf life, infection risk, and risk of delay while preparing during category one cesarean section. There is no significant difference or preference to the other alternative as per current use. Aims and Objectives: Patient safety, Cost-effective use of trust resources, problem awareness, Consider improvising on the current practice. Methods: In conjunction with the local department survey results, many studies support the change. Results: More than 50%(15 from 29) are already using Propofol, more than 75% of the participant are willing to shift to Propofol if it becomes standard, and the cost analysis also revealed that Thiopentone 10 X500=£60 Propofol 10X200= £5.20, Cost of Thiopentone/year =£2190. Approximately GA in a year =35-40 could cost approximately £20 Propofol, given it is a well-established practice. We could save not only money, but it will be environmentally friendly also to avoid adding any carbon footprints. Recommendation: Thiopentone is rarely used as an induction agent for the category one Caesarean section in our obstetric emergency theatres. Most obstetric anesthetists are using Propofol. Keep both Propofol and thiopentone(powder not withdrawn) in the cat one cesarean section emergency drugs tray ready until the department completely changes the practice protocol. A further retrospective study is required to compare the outcomes for these induction agents through the local database.Keywords: thiopentone, propofol, category 1 caesarean, induction agents
Procedia PDF Downloads 13572 Envisioning Process in Medium Enterprises: An Exploratory Study of Cambodian Living Arts
Authors: Alexandre Bédard, Caroline Coulombe, Jonathan Harvey
Abstract:
Envisioning process (EP) in medium enterprises is treated equally in very small enterprises. Building on the concept of social construction, this study aims to explore how envisioning is constructed in a medium enterprise in which stakeholders are involved and how it is influenced. We use a unique case method based on qualitative data collected through 11 interviews representing various members of the organization. Through the discussion of the findings, we were able to confirm the social construction of the EP and to identify three main stakeholders responsible for the construction of the vision, mainly political and social powers, actors of the organization, and financial providers. Moreover, EP is influenced by external factors; in this case, the history of the organization and the value and importance of the art and the culture for Cambodians.Keywords: envisioning process, social constructivism, medium enterprise, legitimacy
Procedia PDF Downloads 10871 Protein Tertiary Structure Prediction by a Multiobjective Optimization and Neural Network Approach
Authors: Alexandre Barbosa de Almeida, Telma Woerle de Lima Soares
Abstract:
Protein structure prediction is a challenging task in the bioinformatics field. The biological function of all proteins majorly relies on the shape of their three-dimensional conformational structure, but less than 1% of all known proteins in the world have their structure solved. This work proposes a deep learning model to address this problem, attempting to predict some aspects of the protein conformations. Throughout a process of multiobjective dominance, a recurrent neural network was trained to abstract the particular bias of each individual multiobjective algorithm, generating a heuristic that could be useful to predict some of the relevant aspects of the three-dimensional conformation process formation, known as protein folding.Keywords: Ab initio heuristic modeling, multiobjective optimization, protein structure prediction, recurrent neural network
Procedia PDF Downloads 20070 An Audit on Tracheal Tube Cuff Pressure Check and Monitoring during Current Practice
Authors: Mahmoud Hassanin, Roshan Thawale, Kiran Yelamati
Abstract:
Background: During current practice, intraoperative regular endotracheal cuff pressure monitoring is not routine, despite the significant number of clinicians interested in checking it after intubation to ensure a good seal and adequate ventilation. Aims and objectives: to highlight that the current practice has no guidance related to regular intra-operative monitoring of the endotracheal tube cuff pressure, which can improve patient safety and post-operative experience. Methods: local department survey was done targeting anaesthetists' current practice, measuring their knowledge and problem awareness to improve patient satisfaction and change the current approach. Results: The participants were not using the manometer, despite their interest in ensuring that the cuff pressure was high enough and there was a proper seal. More than 50% of the participant don't know the ideal range of the endotracheal tube cuff pressure range, and 32% don't know whether it is available or not in the theatre. Despite the previous finding, 100% of the participants used different methods to ensure adequate cuff pressure. The collected data revealed that at least 26% of the participant confirmed that they had seen patients having post-intubation complications. Conclusion: There is an increasing importance placed on quality assurance. Clinical practice varies widely among practitioners, with the only consistency being the omission of cuff manometers during routine intra-operative management, despite their proven benefit and efficacy. Encourage the anaesthetists and ODPs to use cuff pressure manometers. The availability of portable pressure manometers can help to maintain safe cuff pressures in patients requiring endotracheal intubation.Keywords: endotracheal cuff pressure, intra-operative monitoring, current practice, patient satisfaction
Procedia PDF Downloads 10269 Memetic Algorithm for Solving the One-To-One Shortest Path Problem
Authors: Omar Dib, Alexandre Caminada, Marie-Ange Manier
Abstract:
The purpose of this study is to introduce a novel approach to solve the one-to-one shortest path problem. A directed connected graph is assumed in which all edges’ weights are positive. Our method is based on a memetic algorithm in which we combine a genetic algorithm (GA) and a variable neighborhood search method (VNS). We compare our approximate method with two exact algorithms Dijkstra and Integer Programming (IP). We made experimentations using random generated, complete and real graph instances. In most case studies, numerical results show that our method outperforms exact methods with 5% average gap to the optimality. Our algorithm’s average speed is 20-times faster than Dijkstra and more than 1000-times compared to IP. The details of the experimental results are also discussed and presented in the paper.Keywords: shortest path problem, Dijkstra’s algorithm, integer programming, memetic algorithm
Procedia PDF Downloads 46168 Magnetic Fluctuations in the Terrestrial Magnetosheath
Authors: Alexandre Gurchumelia, Luca Sorriso-Valvo, David Burgess, Khatuna Elbakidze, Oleg Kharshiladze, Diana Kvaratskhelia
Abstract:
The terrestrial magnetosheath is a highly turbulent medium, with a high level of magnetic1field fluctuations throughout a broad range of scales. These often include an inertial range where a2magnetohydrodynamic turbulent cascade is observed. The multifractal properties of the turbulent3cascade, strictly related to intermittency, are observed here during the transition from quasi-parallel to4quasi-perpendicular magnetic field with respect to the bow-shock normal. The different multifractal5behavior in the two regions is analyzed. A standard coarse-graining technique has been used6to evaluate the generalized dimensions and the corresponding multifractal spectrumf(α). A7p-model fit provided a quantitative measure of multifractality and intermittency, to be compared with8standard indicators: the width of the multifractal spectrum, the peak of the kurtosis, and its scaling9exponent. Results show a clear transition and sharp differences in the intermittency properties for the two regions.Keywords: magnetos heath, turbulence, multifractal, instabilities
Procedia PDF Downloads 17167 Psychosocial Processes and Strategies behind Islamic Deradicalisation: A Scoping Review
Authors: Carvalho M. Catia, Pinto R. Isabel, Azevedo F. Luis, Guerreiro, T. Alexandre, Barbosa R. Mariana, Pinto S. Marta
Abstract:
Due to the loss of territory, foreign terrorist fighters who have joined Islamic State are returning to their home countries. In order to counter this threat to international security, it is important to implement deradicalisation programmes, through strategies and processes that can reverse radicalisation. The objectives of this scoping review - which is underway - are to provide a comprehensive overview of the programmes being implemented, its main characteristics, the main motives and processes leading to deradicalisation, and to identify the key findings and the existing gaps in the literature. The methodology to be implemented in this scoping review follows the guidelines proposed by Arksey and O’Malley and by The Joanna Briggs Institute. The main results will be the development of a synthesis map of the deradicalisation programmes existing in the world, its main features, and recommendations to policy-makers and professionals.Keywords: deradicalisation strategies, psychosocial processes, radicalisation, terrorism
Procedia PDF Downloads 38566 Generating 3D Anisotropic Centroidal Voronoi Tessellations
Authors: Alexandre Marin, Alexandra Bac, Laurent Astart
Abstract:
New numerical methods for PDE resolution (such as Finite Volumes (FV) or Virtual Elements Method (VEM)) open new needs in terms of meshing of domains of interest, and in particular, polyhedral meshes have many advantages. One way to build such meshes consists of constructing Restricted Voronoi Diagrams (RVDs) whose boundaries respect the domain of interest. By minimizing a function defined for RVDs, the shapes of cells can be controlled, e.g., elongated according to user-defined directions or adjusted to comply with given aspect ratios (anisotropy) and density variations. In this paper, our contribution is threefold: First, we introduce a new gradient formula for the Voronoi tessellation energy under a continuous anisotropy field. Second, we describe a meshing algorithm based on the optimisation of this function that we validate against state-of-the-art approaches. Finally, we propose a hierarchical approach to speed up our meshing algorithm.Keywords: anisotropic Voronoi diagrams, meshes for numerical simulations, optimisation, volumic polyhedral meshing
Procedia PDF Downloads 9765 Fast Short-Term Electrical Load Forecasting under High Meteorological Variability with a Multiple Equation Time Series Approach
Authors: Charline David, Alexandre Blondin Massé, Arnaud Zinflou
Abstract:
In 2016, Clements, Hurn, and Li proposed a multiple equation time series approach for the short-term load forecasting, reporting an average mean absolute percentage error (MAPE) of 1.36% on an 11-years dataset for the Queensland region in Australia. We present an adaptation of their model to the electrical power load consumption for the whole Quebec province in Canada. More precisely, we take into account two additional meteorological variables — cloudiness and wind speed — on top of temperature, as well as the use of multiple meteorological measurements taken at different locations on the territory. We also consider other minor improvements. Our final model shows an average MAPE score of 1:79% over an 8-years dataset.Keywords: short-term load forecasting, special days, time series, multiple equations, parallelization, clustering
Procedia PDF Downloads 9564 Patient-Specific Modeling Algorithm for Medical Data Based on AUC
Authors: Guilherme Ribeiro, Alexandre Oliveira, Antonio Ferreira, Shyam Visweswaran, Gregory Cooper
Abstract:
Patient-specific models are instance-based learning algorithms that take advantage of the particular features of the patient case at hand to predict an outcome. We introduce two patient-specific algorithms based on decision tree paradigm that use AUC as a metric to select an attribute. We apply the patient specific algorithms to predict outcomes in several datasets, including medical datasets. Compared to the patient-specific decision path (PSDP) entropy-based and CART methods, the AUC-based patient-specific decision path models performed equivalently on area under the ROC curve (AUC). Our results provide support for patient-specific methods being a promising approach for making clinical predictions.Keywords: approach instance-based, area under the ROC curve, patient-specific decision path, clinical predictions
Procedia PDF Downloads 47263 Institutional Capacity and Corruption: Evidence from Brazil
Authors: Dalson Figueiredo, Enivaldo Rocha, Ranulfo Paranhos, José Alexandre
Abstract:
This paper analyzes the effects of institutional capacity on corruption. Methodologically, the research design combines both descriptive and multivariate statistics to examine two original datasets based on secondary data. In particular, we employ a principal component model to estimate an indicator of institutional capacity for both state audit institutions and subnational judiciary courts. Then, we estimate the effect of institutional capacity on two dependent variables: (1) incidence of administrative irregularities and (2) time elapsed to judge corruption cases. The preliminary results using ordinary least squares, negative binomial and Tobit models suggest the same conclusions: higher the institutional audit capacity, higher is the probability of detecting a corruption case. On the other hand, higher the institutional capacity of state judiciary, the lower is the time to judge corruption cases.Keywords: institutional capacity, corruption, state level institutions, evidence from Brazil
Procedia PDF Downloads 36362 Selective Solvent Extraction of Calcium and Magnesium from Concentrate Nickel Solutions Using Mixtures of Cyanex 272 and D2EHPA
Authors: Alexandre S. Guimarães, Marcelo B. Mansur
Abstract:
The performance of organophosphorus extractants Cyanex 272 and D2EHPA on the purification of concentrate nickel sulfate solutions was evaluated. Batch scale tests were carried out at pH range of 2 to 7 using a laboratory solution simulating concentrate nickel liquors as those typically obtained when sulfate intermediates from nickel laterite are re-leached and treated for the selective removal of cobalt, zinc, manganese and copper with Cyanex 272 ([Ca] = 0.57 g/L, [Mg] = 3.2 g/L, and [Ni] = 88 g/L). The increase on the concentration of D2EHPA favored the calcium extraction. The extraction of magnesium is dependent on the pH and of ratio of extractants D2EHPA and Cyanex 272 in the organic phase. The composition of the investigated organic phase did not affect nickel extraction. The number of stages is dependent on the magnesium extraction. The most favorable operating condition to selectively remove calcium and magnesium was determined.Keywords: solvent extraction, organophosphorus extractants, alkaline earth metals, nickel
Procedia PDF Downloads 51961 Analysis of the Volatile Organic Compounds of Tillandsia Flowers by HS-SPME/GC-MS
Authors: Alexandre Gonzalez, Zohra Benfodda, David Bénimélis, Jean-Xavier Fontaine, Roland Molinié, Patrick Meffre
Abstract:
Volatile organic compounds (VOCs) emitted by flowers play an important role in plant ecology. However, the Tillandsia genus has been scarcely studied according to the VOCs emitted by flowers. Tillandsia are epiphytic flowering plants belonging to the Bromeliaceae family. The VOCs composition of twelve unscented and two faint-scented Tillandsia species was studied. The headspace solid phase microextraction coupled with gas chromatography combined with mass spectrometry method was used to explore the chemical diversity of the VOCs. This study allowed the identification of 65 VOCs among the fourteen species, and between six to twenty-five compounds were identified in each of the species.Keywords: tillandsia, headspace solid phase microextraction (HS-SPME), gas chromatography-mass spectrometry (GC-MS), scentless flowers, volatile organic compounds (VOCs), PCA analysis, heatmap
Procedia PDF Downloads 11260 Mesotrione and Tembotrione Applied Alone or in Tank-Mix with Atrazine on Weed Control in Elephant Grass
Authors: Alexandre M. Brighenti
Abstract:
The experiment was carried out in Valença, Rio de Janeiro State, Brazil, to evaluate the selectivity and weed control of carotenoid biosynthesis inhibiting herbicides applied alone or in combination with atrazine in elephant grass crop. The treatments were as follows: mesotrione (0.072 and 0.144 kg ha-1 + 0.5% v/v mineral oil - Assist®), tembotrione (0.075 and 0.100 kg ha-1 + 0.5% v/v mineral oil - Aureo®), atrazine + mesotrione (1.25 + 0.072 kg ha-1 + 0.5% v/v mineral oil - Assist®), atrazine + tembotrione (1.25 + 0.100 kg ha-1 + 0.5% v/v mineral oil - Aureo®), atrazine + mesotrione (1.25 + 0.072 kg ha-1), atrazine + tembotrione (1.25 + 0.100 kg ha-1) and two controls (hoed and unhoed check). Two application rates of mesotrione with the addition of mineral oil or the tank mixture of atrazine plus mesotrione, with or without the addition of mineral oil, did not provide injuries capable to reduce elephant grass forage yield. Tembotrione was phytotoxic to elephant grass when applied with mineral oil. Atrazine and tembotrione in a tank-mix, with or without mineral oil, were also phytotoxic to elephant grass. All treatments provided satisfactory weed control.Keywords: forage, Napier grass, pasture, Pennisetum purpureum, weeds
Procedia PDF Downloads 27659 Modeling of Crack Propagation Path in Concrete with Coarse Trapezoidal Aggregates by Boundary Element Method
Authors: Chong Wang, Alexandre Urbano Hoffmann
Abstract:
Interaction between a crack and a trapezoidal aggregate in a single edge notched concrete beam is simulated using boundary element method with an automatic crack extension program. The stress intensity factors of the growing crack are obtained from the J-integral. Three crack extension paths: deflecting around the particulate, growing along the interface and penetrating into the particulate are achieved in terms of the mismatch state of mechanical characteristics of matrix and the particulate. The toughening is also given by the ratio of stress intensity factors. The results reveal that as stress shielding occurs, toughening is obtained when the crack is approaching to a stiff and strong aggregate weakly bonded to a relatively soft matrix. The present work intends to help for the design of aggregate reinforced concretes.Keywords: aggregate concrete, boundary element method, two-phase composite, crack extension path, crack/particulate interaction
Procedia PDF Downloads 42258 Chemical and Mechanical Characterization of Composites Reinforced with Coconut Fiber in the Polymeric Matrix of Recycled PVC
Authors: Luiz C. G. Pennafort Jr., Alexandre de S. Rios, Enio P. de Deus
Abstract:
In the search for materials that replace conventional polymers in order to preserve natural resources, combined with the need to minimize the problems arising from environmental pollution generated by plastic waste, comes the recycled materials biodegradable, especially the composites reinforced with natural fibers. However, such materials exhibit properties little known, requiring studies of manufacturing methods and characterization of these composites. This article shows informations about preparation and characterization of a composite produced by extrusion, which consists of recycled PVC derived from the recycling of materials discarded, added of the micronized coconut fiber. The recycled PVC with 5% of micronized fiber were characterized by X-ray diffraction, thermogravimetric, differential scanning calorimetry, mechanical analysis and optical microscopy. The use of fiber in the composite caused a decrease in its specific weight, due to the lower specific weight of fibers and the appearance of porosity, in addition to the decrease of mechanical properties.Keywords: recycled PVC, coconut fiber, characterization, composites
Procedia PDF Downloads 46057 Hairy Beggarticks (Bidens pilosa L. - Asteraceae) Control in Sunflower Fields Using Pre-Emergence Herbicides
Authors: Alexandre M. Brighenti
Abstract:
One of the most damaging species in sunflower crops in Brazil is the hairy beggarticks (Bidens pilosa L.). The large number of seeds, the various vegetative cycles during the year, the staggered germination and the scarcity of selective and effective herbicides to control this weed in sunflower are some of attributes that hinder the effectiveness in controlling hairy beggarticks populations. The experiment was carried out with the objectives of evaluating the control of hairy beggarticks plants in sunflower crops, and to assess sunflower tolerance to residual herbicides. The treatments were as follows: S-metolachlor (1,200 and 2,400 g ai ha-1), flumioxazin (60 and 120 g ai ha-1), sulfentrazone (150 and 300 g ai ha-1) and two controls (weedy and weed-free check). Phytotoxicity on sunflower plants, percentage of control and density of hairy beggarticks plants, sunflower stand and plant height, head diameter, oil content and sunflower yield were evaluated. The herbicides flumioxazin and sulfentrazone were the most efficient in hairy beggarticks control. S-metolachlor provided acceptable control levels. S-metolachlor (1,200 g ha-1), flumioxazin (60 g ha-1) and sulfentrazone (150 g ha-1) were the most selective doses for sunflower crop.Keywords: flumioxazin, Helianthus annuus, S-metolachlor, sulfentrazone, weeds
Procedia PDF Downloads 35056 Integrated Target Tracking and Control for Automated Car-Following of Truck Platforms
Authors: Fadwa Alaskar, Fang-Chieh Chou, Carlos Flores, Xiao-Yun Lu, Alexandre M. Bayen
Abstract:
This article proposes a perception model for enhancing the accuracy and stability of car-following control of a longitudinally automated truck. We applied a fusion-based tracking algorithm on measurements of a single preceding vehicle needed for car-following control. This algorithm fuses two types of data, radar and LiDAR data, to obtain more accurate and robust longitudinal perception of the subject vehicle in various weather conditions. The filter’s resulting signals are fed to the gap control algorithm at every tracking loop composed by a high-level gap control and lower acceleration tracking system. Several highway tests have been performed with two trucks. The tests show accurate and fast tracking of the target, which impacts on the gap control loop positively. The experiments also show the fulfilment of control design requirements, such as fast speed variations tracking and robust time gap following.Keywords: object tracking, perception, sensor fusion, adaptive cruise control, cooperative adaptive cruise control
Procedia PDF Downloads 22555 Comparison of Classical Computer Vision vs. Convolutional Neural Networks Approaches for Weed Mapping in Aerial Images
Authors: Paulo Cesar Pereira Junior, Alexandre Monteiro, Rafael da Luz Ribeiro, Antonio Carlos Sobieranski, Aldo von Wangenheim
Abstract:
In this paper, we present a comparison between convolutional neural networks and classical computer vision approaches, for the specific precision agriculture problem of weed mapping on sugarcane fields aerial images. A systematic literature review was conducted to find which computer vision methods are being used on this specific problem. The most cited methods were implemented, as well as four models of convolutional neural networks. All implemented approaches were tested using the same dataset, and their results were quantitatively and qualitatively analyzed. The obtained results were compared to a human expert made ground truth for validation. The results indicate that the convolutional neural networks present better precision and generalize better than the classical models.Keywords: convolutional neural networks, deep learning, digital image processing, precision agriculture, semantic segmentation, unmanned aerial vehicles
Procedia PDF Downloads 24554 Shock and Particle Velocity Determination from Microwave Interrogation
Authors: Benoit Rougier, Alexandre Lefrancois, Herve Aubert
Abstract:
Microwave interrogation in the range 10-100 GHz is identified as an advanced technique to investigate simultaneously shock and particle velocity measurements. However, it requires the understanding of electromagnetic wave propagation in a multi-layered moving media. The existing models limit their approach to wave guides or evaluate the velocities with a fitting method, restricting therefore the domain of validity and the precision of the results. Moreover, few data of permittivity on high explosives at these frequencies under dynamic compression have been reported. In this paper, shock and particle velocities are computed concurrently for steady and unsteady shocks for various inert and reactive materials, via a propagation model based on Doppler shifts and signal amplitude. Refractive index of the material under compression is also calculated. From experimental data processing, it is demonstrated that Hugoniot curve can be evaluated. The comparison with published results proves the accuracy of the proposed method. This microwave interrogation technique seems promising for shock and detonation waves studies.Keywords: electromagnetic propagation, experimental setup, Hugoniot measurement, shock propagation
Procedia PDF Downloads 20953 Restraint and Seclusion: Individual and Environmental Characteristics of the Educators Super Users
Authors: Caroline A. Mathieu, Steve Geoffrion, Alexandre Dumais, Denis Lafortune
Abstract:
In Quebec, troubled youths stay in a rehabilitation Center (RC), and educators in RC’S are particularly at risk of exposure to workplace violence. In order to manage youth violence and protect youth safety or their own, educators can resort to restraint and seclusion (R&S) strategies. To our best knowledge, in the literature, no study was found on the topic of R&S super users either in psychiatry or in a rehabilitation center. The objective of this study is to explore the differences between R&S super users and normal users among educators in terms of individual and environmental characteristics, over an eight weeks period. The 278 participants were volunteers recruited from 36 units that foster around 8 to 12 youths per unit, in a suburb of Montreal; Quebec, Canada. The results indicate that among the variables that were studied, only fear of violence and past exposure to violence at work characterized the R&S super users. These results suggest that exposure to violence in the workplace might increase the anticipation and fear of violence from a youth; this is concordant with the results indicating that these variables are the ones separating normal users from super users.Keywords: seclusion and restraint, violence, youth, educators
Procedia PDF Downloads 18252 Enhancing Human Mobility Exoskeleton Comfort Using Admittance Controller
Authors: Alexandre Rabaseda, Emelie Seguin, Marc Doumit
Abstract:
Human mobility exoskeletons have been in development for several years and are becoming increasingly efficient. Unfortunately, user comfort was not always a priority design criterion throughout their development. To further improve this technology, exoskeletons should operate and deliver assistance without causing discomfort to the user. For this, improvements are necessary from an ergonomic point of view. The device’s control method is important when endeavoring to enhance user comfort. Exoskeleton or rehabilitation device controllers use methods of control called interaction controls (admittance and impedance controls). This paper proposes an extended version of an admittance controller to enhance user comfort. The control method used consists of adding an inner loop that is controlled by a proportional-integral-derivative (PID) controller. This allows the interaction force to be kept as close as possible to the desired force trajectory. The force-tracking admittance controller modifies the actuation force of the system in order to follow both the desired motion trajectory and the desired relative force between the user and the exoskeleton.Keywords: mobility assistive device, exoskeleton, force-tracking admittance controller, user comfort
Procedia PDF Downloads 14851 Controller Design and Experimental Evaluation of a Motorized Assistance for a Patient Transfer Floor Lift
Authors: Donatien Callon, Ian Lalonde, Mathieu Nadeau, Alexandre Girard
Abstract:
Patient transfer is a challenging, critical task because it exposes caregivers to injury risks. Available transfer devices, like floor lifts, lead to improvements but are far from perfect. They do not eliminate the caregivers’ risk of musculoskeletal disorders, and they can be burdensome to use due to their poor maneuverability. This paper presents a new motorized floor lift with a single central motorized wheel connected to an instrumented handle. Admittance controllers are designed to 1) improve the device maneuverability, 2) reduce the required caregiver effort, and 3) ensure the security and comfort of patients. Two controller designs, one with a linear admittance law and a non-linear admittance law with variable damping, were developed and implemented on a prototype. Tests were performed on seven participants to evaluate the performance of the assistance system and the controllers. The experimental results show that 1) the motorized assistance with the variable damping controller improves maneuverability by 28%, 2) reduces the amount of effort required to push the lift by 66%, and 3) provides the same level of patient comfort compared to a standard unassisted floor lift.Keywords: floor lift, human robot interaction, admittance controller, variable admittance
Procedia PDF Downloads 9850 Corrosion Behavior of Different Electroplated Systems Coated With Physical Vapor Deposition
Authors: Jorge Santos, Ana V. Girão, F. J. Oliveira, Alexandre C. Bastos
Abstract:
Protective or decorative coatings containing hexavalent chromium compounds are still used on metal and plastic parts. These hexavalent chromium compounds represent a risk to living beings and the environment, and, for this reason, there is a great need to investigate alternatives. Physical Vapor Deposition (PVD) is an environmentally friendly process that allows the deposition of wear and corrosion resistant thin films with excellent optical properties. However, PVD thin films are porous and if deposited onto low corrosion resistant substrates, lead to a degradation risk. The corrosion behavior of chromium-free electroplated coating systems finished with magnetron sputtered PVD thin films was investigated in this work. The electroplated systems consisted of distinct nickel layers deposited on top of a copper interlayer on acrylonitrile butadiene styrene (ABS) plates. Electrochemical and corrosion evaluation was conducted by electrochemical impedance spectroscopy and polarization curves on the different electroplated coating systems, with and without PVD thin film on top. The results show that the corrosion resistance is lower for the electroplated coating systems finished with PVD thin film for extended exposure periods when compared to those without the PVD overlay.Keywords: PVD, electroplating, corrosion, thin film
Procedia PDF Downloads 14149 Antarctica, Global Change and Deaf Education in Brazil
Authors: Luiz Antonio Da Costa Rodrigues, Mara Aparecida De Castilho Lopes, Alexandre Santos Alencar
Abstract:
Teaching of science must transcend simple transmission of fundamental concepts and allow scientific literacy, as a process for understanding the human being as an integral part of a complex and interdependent whole. In this context, approaching the theme ‘Antarctica’ in deaf education is an important advance for teaching, considering that that continent has direct interactions with the climatic and environmental system of the planet. Therefore, textbooks can be important tools to enable the Deaf Community to access the discussion about the natural environment. A specific script was used to analyze textbooks adopted by schools in the Rio de Janeiro Metropolitan Region. Results show that none of the 14 analyzed books have a specific chapter on the theme, some presents images of the continent without reference to their environmental importance, and the complementary texts present in the analyzed material do not address the theme either. It is concluded that the study on Antarctica and global changes in elementary education is still incipient and the material used by most Brazilian public schools does not contemplate that subject in an accessible way for the deaf person. This fact represents the distance between deaf students and their environment, denoting the need for actions to promote that and other neglected themes in Science teaching.Keywords: Antarctica, deaf education, science teaching, textbook
Procedia PDF Downloads 271