Computer applications in the Transport and Communications Division of the Economic Commission for Latin America and the Caribbean

Presenta la experiencia de la Division de Transportes y Comunicaciones en el uso de computadores para aplicaciones substantivas. Examina los sistemas aplicados - codigo de puertos, ISIS, TRANDIS, COMPA -; el uso de procesamiento de textos en la preparacion de documentos de investigacion e informes y en la correspondencia, y entrega algunas consideraciones con respecto al uso de los microcomputadores.

Computer intensive methods for controlling bias in a generalized species diversity index

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A hybrid neutron diffraction and computer simulation study on the solvation of N-methylformamide in dimethylsulfoxide

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

Practising Arithmetic Using Educational Video Games with an Interpersonal Computer

Studies show the positive effects that video games can have on student performance and attitude towards learning. In the past few years, strategies have been generated to optimize the use of technological resources with the aim of facilitating widespread adoption of technology in the classroom. Given its low acquisition and maintenance costs, the interpersonal computer allows individual interaction and simultaneous learning with large groups of students. The purpose of this work was to compare arithmetical knowledge acquired by third-grade students through the use of game-based activities and non-game-based activities using an interpersonal computer, with knowledge acquired through the use of traditional paper-and-pencil activities, and to analyze their impact in various socio-cultural contexts. To do this, a quasi-experimental study was conducted with 271 students in three different countries (Brazil, Chile, and Costa Rica), in both rural and urban schools. A set of educational games for practising arithmetic was developed and tested in six schools within these three countries. Results show that there were no significant differences (ANCOVA) in the learning acquired from game-based vs. non-game-based activities. However, both showed a significant difference when compared with the traditional method. Additionally, both groups using the interpersonal computer showed higher levels of student interest than the traditional method group, and these technological methods were seen to be especially effective in increasing learning among weaker students.

Fluorescence Level of Composites Assessed by Computer Processing of Digital Images - ScanWhite

The human dentition is naturally translucent, opalescent and fluorescent. Differences between the level of fluorescence of tooth structure and restorative materials may result in distinct metameric properties and consequently perceptible disparate esthetic behavior, which impairs the esthetic result of the restorations, frustrating both patients and staff. In this study, we evaluated the level of fluorescence of different composites (Durafill in tones A2 (Du), Charisma in tones A2 (Ch), Venus in tone A2 (Ve), Opallis enamel and dentin in tones A2 (OPD and OPE), Point 4 in tones A2 (P4), Z100 in tones A2 ( Z1), Z250 in tones A2 (Z2), Te-Econom in tones A2 (TE), Tetric Ceram in tones A2 (TC), Tetric Ceram N in tones A1, A2, A4 (TN1, TN2, TN4), Four seasons enamel and dentin in tones A2 (and 4SD 4SE), Empress Direct enamel and dentin in tones A2 (EDE and EDD) and Brilliant in tones A2 (Br)). Cylindrical specimens were prepared, coded and photographed in a standardized manner with a Canon EOS digital camera (400 ISO, 2.8 aperture and 1/ 30 speed), in a dark environment under the action of UV light (25 W). The images were analyzed with the software ScanWhite©-DMC/Darwin systems. The results showed statistical differences between the groups (p < 0.05), and between these same groups and the average fluorescence of the dentition of young (18 to 25 years) and adults (40 to 45 years) taken as control. It can be concluded that: Composites Z100, Z250 (3M ESPE) and Point 4 (Kerr) do not match with the fluorescence of human dentition and the fluorescence of the materials was found to be affected by their own tone.

A nature-inspired approach to speed up optimum-path forest clustering and its application to intrusion detection in computer networks

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

Computer graphics applied to anatomy: a study of two bio-cad modeling methods on finite element analysis of human edentulous hemi-mandible

Modeling is a step to perform a finite element analysis. Different methods of model construction are reported in literature, as the Bio-CAD modeling. The purpose of this study was to perform a model evaluation and application using two methods of Bio-CAD modeling from human edentulous hemi-mandible on the finite element analysis. From CT scans of dried human skull was reconstructed a stereolithographic model. Two methods of modeling were performed: STL conversion approach (Model 1) associated to STL simplification and reverse engineering approach (Model 2). For finite element analysis was used the action of lateral pterygoid muscle as loading condition to assess total displacement (D), equivalent von-Mises stress (VM) and maximum principal stress (MP). Two models presented differences on the geometry regarding surface number (1834 (model 1); 282 (model 2)). Were observed differences in finite element mesh regarding element number (30428 nodes/16683 elements (model 1); 15801 nodes/8410 elements (model 2). D, VM and MP stress areas presented similar distribution in two models. The values were different regarding maximum and minimum values of D (ranging 0-0.511 mm (model 1) and 0-0.544 mm (model 2), VM stress (6.36E-04-11.4 MPa (model 1) and 2.15E-04-14.7 MPa (model 2) and MP stress (-1.43-9.14 MPa (model 1) and -1.2-11.6 MPa (model 2). From two methods of Bio-CAD modeling, the reverse engineering presented better anatomical representation compared to the STL conversion approach. The models presented differences in the finite element mesh, total displacement and stress distribution.

Evaluation of the Computer-based Battery for Oral Language (BILOv3) through the Rasch model for a Brazilian Sample

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

An esthetics rehabilitation with computer-aided design/ computer-aided manufacturing technology

This paper describes a case of a rehabilitation involving Computer Aided Design/Computer Aided Manufacturing (CAD-CAM) system in implant supported and dental supported prostheses using zirconia as framework. The CAD-CAM technology has developed considerably over last few years, becoming a reality in dental practice. Among the widely used systems are the systems based on zirconia which demonstrate important physical and mechanical properties of high strength, adequate fracture toughness, biocompatibility and esthetics, and are indicated for unitary prosthetic restorations and posterior and anterior framework. All the modeling was performed by using CAD-CAM system and prostheses were cemented using resin cement best suited for each situation. The rehabilitation of the maxillary arch using zirconia framework demonstrated satisfactory esthetic and functional results after a 12-month control and revealed no biological and technical complications. This article shows the important of use technology CAD/CAM in the manufacture of dental prosthesis and implant-supported.

Computer simulation of configurational properties of partially ionized polyelectrolytes

Monte Carlo simulation methods were used in order to study the conformational properties of partially ionized polyelectrolyte chains with Debye-Hückel screening in 1:1 electrolyte solution at room temperature. Configurational properties such as the distributions of probability for the square end to end distances, for the square radii of gyration and for the angles between polyion bonds were investigated as a function of the chain ionization and the salt concentration. © 1993.

Evolutionary stages of environmental management in computer companies located in Brazil: case studies

This study aims at identifying which environmental management practices computer companies located in Brazil are adopting, and classifying these companies according to the evolutionary stages of environmental management. For such, the case study research method was used at three companies. Results show that environmental management in the sector is geared towards compliance with laws and eco-efficiency, aimed at cutting costs. It was concluded that classification does not occur in a linear manner with defined borders, and that the multinational companies located in Brazil are greatly influenced by their foreign head offices, which are at more advanced evolutionary stages.

The Perception of Natural, Cell Phone, and Computer-Synthesized Speech During The Performance Of Simultaneous Visual-Motor Tasks

This study investigated the influence of top-down and bottom-up information on speech perception in complex listening environments. Specifically, the effects of listening to different types of processed speech were examined on intelligibility and on simultaneous visual-motor performance. The goal was to extend the generalizability of results in speech perception to environments outside of the laboratory. The effect of bottom-up information was evaluated with natural, cell phone and synthetic speech. The effect of simultaneous tasks was evaluated with concurrent visual-motor and memory tasks. Earlier works on the perception of speech during simultaneous visual-motor tasks have shown inconsistent results (Choi, 2004; Strayer & Johnston, 2001). In the present experiments, two dual-task paradigms were constructed in order to mimic non-laboratory listening environments. In the first two experiments, an auditory word repetition task was the primary task and a visual-motor task was the secondary task. Participants were presented with different kinds of speech in a background of multi-speaker babble and were asked to repeat the last word of every sentence while doing the simultaneous tracking task. Word accuracy and visual-motor task performance were measured. Taken together, the results of Experiments 1 and 2 showed that the intelligibility of natural speech was better than synthetic speech and that synthetic speech was better perceived than cell phone speech. The visual-motor methodology was found to demonstrate independent and supplemental information and provided a better understanding of the entire speech perception process. Experiment 3 was conducted to determine whether the automaticity of the tasks (Schneider & Shiffrin, 1977) helped to explain the results of the first two experiments. It was found that cell phone speech allowed better simultaneous pursuit rotor performance only at low intelligibility levels when participants ignored the listening task. Also, simultaneous task performance improved dramatically for natural speech when intelligibility was good. Overall, it could be concluded that knowledge of intelligibility alone is insufficient to characterize processing of different speech sources. Additional measures such as attentional demands and performance of simultaneous tasks were also important in characterizing the perception of different kinds of speech in complex listening environments.

Assessing Needs for Computer Pest Management Software in Nebraska Agriculture

A mail survey was conducted to assess current computer hardware use and perceived needs of potential users for software related to crop pest management in Nebraska. Surveys were sent to University of Nebraska-Lincoln agricultural extension agents, agribusiness personnel (including independent crop consultants), and crop producers identified by extension agents as computer users. There were no differences between the groups in several aspects of computer hardware use (percentage computer use, percentage IBM-compatible computer, amount of RAM memory, percentage with hard drive, hard drive size, or monitor graphics capability). Responses were similar among the three groups in several areas that are important to crop pest management (pest identification, pest biology, treatment decision making, control options, and pesticide selection), and a majority of each group expressed the need for additional sources of such information about insects, diseases, and weeds. However, agents mentioned vertebrate pest management information as a need more often than the other two groups. Also, majorities of each group expressed an interest in using computer software, if available, to obtain information in these areas. Appropriate software to address these needs should find an audience among all three groups.

A computer-controlled color vision test for children based on the Cambridge Colour Test

The present study aimed at providing conditions for the assessment of color discrimination in children using a modified version of the Cambridge Colour Test (CCT, Cambridge Research Systems Ltd., Rochester, UK). Since the task of indicating the gap of the Landolt C used in that test proved counterintuitive and/or difficult for young children to understand, we changed the target Stimulus to a patch of color approximately the size of the Landolt C gap (about 7 degrees Of Visual angle at 50 cm from the monitor). The modifications were performed for the CCT Trivector test which measures color discrimination for the protan, deutan and tritan confusion lines. Experiment I Sought to evaluate the correspondence between the CCT and the child-friendly adaptation with adult subjects (n = 29) with normal color vision. Results showed good agreement between the two test versions. Experiment 2 tested the child-friendly software with children 2 to 7 years old (n = 25) using operant training techniques for establishing and maintaining the subjects` performance. Color discrimination thresholds were progressively lower as age increased within the age range tested (2 to 30 years old), and the data-including those obtained for children-fell within the range of thresholds previously obtained for adults with the CCT. The protan and deutan thresholds were consistently lower than tritan thresholds, a pattern repeatedly observed in adults tested with the CCT. The results demonstrate that the test is fit for assessment of color discrimination in young children and may be a useful tool for the establishment of color vision thresholds during development.