Computer aided manufacturing of geometric models

As systems for computer-aided-design and production of mechanical parts have developed, there has arisen a need for techniques for the comprehensive description of the desired part, including its 3-D shape. The creation and manipulation of shapes is generally known as geometric modelling. It is desirable that links be established between geometric modellers and machining programs. Currently, unbounded APT and some bounded geometry systems are being widely used in manufacturing industry for machining operations such as: milling, drilling, boring and turning, applied mainly to engineering parts. APT systems, however, are presently only linked to wire-frame drafting systems. The combination of a geometric modeller and APT will provide a powerful manufacturing system for industry from the initial design right through part manufacture using NC machines. This thesis describes a recently developed interface (ROMAPT) between a bounded geometry modeller (ROMULUS) and an unbounded NC processor (APT). A new set of theoretical functions and practical algorithms for the computer aided manufacturing of 3D solid geometric model has been investigated. This work has led to the development of a sophisticated computer program, ROMAPT, which provides a new link between CAD (in form of a goemetric modeller ROMULUS) and CAM (in form of the APT NC system). ROMAPT has been used to machine some engineering prototypes successfully both in soft foam material and aluminium. It has been demonstrated above that the theory and algorithms developed by the author for the development of computer aided manufacturing of 3D solid modelling are both valid and applicable. ROMAPT allows the full potential of a solid geometric modeller (ROMULUS) to be further exploited for NC applications without requiring major investment in new NC processor. ROMAPT supports output in APT-AC, APT4 and the CAM-I SSRI NC languages.

A knowledge-based system for process planning in a seamless steel tube plant

The thesis describes the work carried out to develop a prototype knowledge-based system 'KBS-SETUPP' to generate process plans for the manufacture of seamless tubes. The work is specifically related to a plant in which hollows are made from solid billets using a rotary piercing process and then reduced to required size and finished properties using the fixed plug cold drawing process. The thesis first discusses various methods of tube production in order to give a general background of tube manufacture. Then a review of the automation of the process planning function is presented in terms of its basic sub-tasks and the techniques and suitability of a knowledge-based system is established. In the light of such a review and a case study, the process planning problem is formulated in the domain of seamless tube manufacture, its basic sub-tasks are identified and capabilities and constraints of the available equipment in the specific plant are established. The task of collecting and collating the process planning knowledge in seamless tube manufacture is discussed and is mostly fulfilled from domain experts, analysing of existing manufacturing records specific to plant, textbooks and applicable Standards. For the cold drawing mill, tube-drawing schedules have been rationalised to correspond with practice. The validation of such schedules has been achieved by computing the process parameters and then comparing these with the drawbench capacity to avoid over-loading. The existing models cannot be simulated in the computer program as such, therefore a mathematical model has been proposed which estimates the process parameters which are in close agreement with experimental values established by other researchers. To implement the concepts, a Knowledge-Based System 'KBS- SETUPP' has been developed on Personal Computer using Turbo- Prolog. The system is capable of generating process plans, production schedules and some additional capabilities to supplement process planning. The system generated process plans have been compared with the actual plans of the company and it has been shown that the results are satisfactory and encouraging and that the system has the capabilities which are useful.

Computer simulation of form-roll design

Changes in modern structural design have created a demand for products which are light but possess high strength. The objective is a reduction in fuel consumption and weight of materials to satisfy both economic and environmental criteria. Cold roll forming has the potential to fulfil this requirement. The bending process is controlled by the shape of the profile machined on the periphery of the rolls. A CNC lathe can machine complicated profiles to a high standard of precision, but the expertise of a numerical control programmer is required. A computer program was developed during this project, using the expert system concept, to calculate tool paths and consequently to expedite the procurement of the machine control tapes whilst removing the need for a skilled programmer. Codifying the expertise of a human and the encapsulation of knowledge within a computer memory, destroys the dependency on highly trained people whose services can be costly, inconsistent and unreliable. A successful cold roll forming operation, where the product is geometrically correct and free from visual defects, is not easy to attain. The geometry of the sheet after travelling through the rolling mill depends on the residual strains generated by the elastic-plastic deformation. Accurate evaluation of the residual strains can provide the basis for predicting the geometry of the section. A study of geometric and material non-linearity, yield criteria, material hardening and stress-strain relationships was undertaken in this research project. The finite element method was chosen to provide a mathematical model of the bending process and, to ensure an efficient manipulation of the large stiffness matrices, the frontal solution was applied. A series of experimental investigations provided data to compare with corresponding values obtained from the theoretical modelling. A computer simulation, capable of predicting that a design will be satisfactory prior to the manufacture of the rolls, would allow effort to be concentrated into devising an optimum design where costs are minimised.

A comparison between static and kinetic visual attention as a means of detecting age-related deterioration of the visual system and driving performance

A critical review of previous research revealed that visual attention tests, such as the Useful Field of View (UFOV) test, provided the best means of detecting age-related changes to the visual system that could potentially increase crash risk. However, the question was raised as to whether the UFOV, which was regarded as a static visual attention test, could be improved by inclusion of kinetic targets that more closely represent the driving task. A computer program was written to provide more information about the derivation of UFOV test scores. Although this investigation succeeded in providing new information, some of the commercially protected UFOV test procedures still remain unknown. Two kinetic visual attention tests (DRTS1 and 2), developed at Aston University to investigate inclusion of kinetic targets in visual attention tests, were introduced. The UFOV was found to be more repeatable than either of the kinetic visual attention tests and learning effects or age did not influence these findings. Determinants of static and kinetic visual attention were explored. Increasing target eccentricity led to reduced performance on the UFOV and DRTS1 tests. The DRTS2 was not affected by eccentricity but this may have been due to the style of presentation of its targets. This might also have explained why only the DRTS2 showed laterality effects (i.e. better performance to targets presented on the left hand side of the road). Radial location, explored using the UFOV test, showed that subjects responded best to targets positioned to the horizontal meridian. Distraction had opposite effects on static and kinetic visual attention. While UFOV test performance declined with distraction, DRTS1 performance increased. Previous research had shown that this striking difference was to be expected. Whereas the detection of static targets is attenuated in the presence of distracting stimuli, distracting stimuli that move in a structured flow field enhances the detection of moving targets. Subjects reacted more slowly to kinetic compared to static targets, longitudinal motion compared to angular motion and to increased self-motion. However, the effects of longitudinal motion, angular motion, self-motion and even target eccentricity were caused by target edge speed variations arising because of optic flow field effects. The UFOV test was more able to detect age-related changes to the visual system than were either of the kinetic visual attention tests. The driving samples investigated were too limited to draw firm conclusions. Nevertheless, the results presented showed that neither the DRTS2 nor the UFOV tests were powerful tools for the identification of drivers prone to crashes or poor driving performance.

A nanoliter volume nuclear magnetic resonance (NMR) system using tunneling magneto-resistive (TMR) sensors to recognize biomolecules

The need to incorporate advanced engineering tools in biology, biochemistry and medicine is in great demand. Many of the existing instruments and tools are usually expensive and require special facilities.^ With the advent of nanotechnology in the past decade, new approaches to develop devices and tools have been generated by academia and industry. ^ One such technology, NMR spectroscopy, has been used by biochemists for more than 2 decades to study the molecular structure of chemical compounds. However, NMR spectrometers are very expensive and require special laboratory rooms for their proper operation. High magnetic fields with strengths in the order of several Tesla make these instruments unaffordable to most research groups.^ This doctoral research proposes a new technology to develop NMR spectrometers that can operate at field strengths of less than 0.5 Tesla using an inexpensive permanent magnet and spin dependent nanoscale magnetic devices. This portable NMR system is intended to analyze samples as small as a few nanoliters.^ The main problem to resolve when downscaling the variables is to obtain an NMR signal with high Signal-To-Noise-Ratio (SNR). A special Tunneling Magneto-Resistive (TMR) sensor design was developed to achieve this goal. The minimum specifications for each component of the proposed NMR system were established. A complete NMR system was designed based on these minimum requirements. The goat was always to find cost effective realistic components. The novel design of the NMR system uses technologies such as Direct Digital Synthesis (DDS), Digital Signal Processing (DSP) and a special Backpropagation Neural Network that finds the best match of the NMR spectrum. The system was designed, calculated and simulated with excellent results.^ In addition, a general method to design TMR Sensors was developed. The technique was automated and a computer program was written to help the designer perform this task interactively.^

Uma interface para o controle de robôs móveis por intermédio de gestos

The main objective of this work was to enable the recognition of human gestures through the development of a computer program. The program created captures the gestures executed by the user through a camera attached to the computer and sends it to the robot command referring to the gesture. They were interpreted in total ve gestures made by human hand. The software (developed in C ++) widely used the computer vision concepts and open source library OpenCV that directly impact the overall e ciency of the control of mobile robots. The computer vision concepts take into account the use of lters to smooth/blur the image noise reduction, color space to better suit the developer's desktop as well as useful information for manipulating digital images. The OpenCV library was essential in creating the project because it was possible to use various functions/procedures for complete control lters, image borders, image area, the geometric center of borders, exchange of color spaces, convex hull and convexity defect, plus all the necessary means for the characterization of imaged features. During the development of the software was the appearance of several problems, as false positives (noise), underperforming the insertion of various lters with sizes oversized masks, as well as problems arising from the choice of color space for processing human skin tones. However, after the development of seven versions of the control software, it was possible to minimize the occurrence of false positives due to a better use of lters combined with a well-dimensioned mask size (tested at run time) all associated with a programming logic that has been perfected over the construction of the seven versions. After all the development is managed software that met the established requirements. After the completion of the control software, it was observed that the overall e ectiveness of the various programs, highlighting in particular the V programs: 84.75 %, with VI: 93.00 % and VII with: 94.67 % showed that the nal program performed well in interpreting gestures, proving that it was possible the mobile robot control through human gestures without the need for external accessories to give it a better mobility and cost savings for maintain such a system. The great merit of the program was to assist capacity in demystifying the man set/machine therefore uses an easy and intuitive interface for control of mobile robots. Another important feature observed is that to control the mobile robot is not necessary to be close to the same, as to control the equipment is necessary to receive only the address that the Robotino passes to the program via network or Wi-Fi.

PENCALC: a program for penetrance estimation in autosomal dominant diseases

We present a computer program developed for estimating penetrance rates in autosomal dominant diseases by means of family kinship and phenotype information contained within the pedigrees. The program also determines the exact 95% credibility interval for the penetrance estimate. Both executable (PenCalc for Windows) and web versions (PenCalcWeb) of the software are available. The web version enables further calculations, such as heterozygosity probabilities and assessment of offspring risks for all individuals in the pedigrees. Both programs can be accessed and down-loaded freely at the home-page address http://www.ib.usp.br/~otto/software.htm.

Using FCD Mapper Software and Landsat Images to Assess Forest Canopy Density in Landscapes in Australia and the Philippines

Using Landsat imagery, forest canopy density (FCD) estimated with the FCD Mapper®, was correlated with predominant height (PDH, measured as the average height of the tallest 50 trees per hectare) for 20 field plots measured in native forest at Noosa Heads, south-east Queensland, Australia. A corresponding image was used to calculate FCD in Leyte Island, the Philippines and was validated on the ground for accuracy. The FCD Mapper was produced for the International Tropical Timber Organisation and estimates FCD as an index of canopy density using reflectance characteristics of Landsat Enhanced Thematic (ETM) Mapper images. The FCD Mapper is a ‘semi-expert’ computer program which uses interactive screens to allow the operator to make decisions concerning the classification of land into bare soil, grass and forest. At Noosa, a positive strong nonlinear relationship (r2 = 0.86) was found between FCD and PDH for 15 field plots with variable PDH but complete canopy closure. An additional five field plots were measured in forest with a broken canopy and the software assessed these plots as having a much lower FCD than forest with canopy closure. FCD estimates for forest and agricultural land in the island of Leyte and subsequent field validation showed that at appropriate settings, the FCD Mapper differentiated between tropical rainforest and banana or coconut plantation. These findings suggest that in forests with a closed canopy this remote sensing technique has promise for forest inventory and productivity assessment. The findings also suggest that the software has promise for discriminating between native forest with a complete canopy and forest which has a broken canopy, such as coconut or banana plantation.

Craniofacial morphology and otitis media with effusion in children

Otitis media with effusion (OME) affects 28-38% of pre-school children, and it occurs due to the dysfunction of the auditory tube. Anatomical development of the auditory tube depends on the craniofacial growth and development. Deviations of normal. craniofacial. morphology and growth using cephatometric studies, may predict the evolution of otitis. Our goal in this paper is to determine if there are differences in craniofacial morphology between children with adenoid enlargement, with and without otitis media with effusion. This is a prospective study in which the sample consisted of 67 children (mate and female) from 5 to 10 years old. All patients presented chronic upper airway obstruction due to tonsil. and adenoid enlargement (>80% degree of obstruction). Thirty-three patients presented otitis media with effusion, for more than 3 months and 34 did not. The tatter composed the control group. Standardized lateral head radiographs were obtained for all. subjects. Radiographs were taken with patient positioned by a cephalostat and stayed with mandibles in centric occlusion and Lips at rest. Radiographs were digitalized and specific Landmarks were identified using a computer program Radiocef 2003, 5th edition. Measurements, angles and tines were taken of the basicranium, maxilla and mandible according to the modified Ricketts analysis. In addition, facial height and facial axis were determined. Children with otitis media with effusion present differences in the morphology of the face, regarding these measures: N-S (anterior cranial base length), N-ANS (upper facial height), ANS-PNS (size of the hard palate), Po-Or.N-Pog (facial depth), Ba-N.Ptm-Gn (facial axis), Go-Me (mandibular Length) and Vaia--Vaip (inferior pharyngeal airway). (C) 2008 Elsevier Ireland Ltd. All rights reserved.

Modelagem e simulação de sistema logístico de distribuição de carne de frango

O sistema logístico para distribuição de produtos acabados caracteriza-se pela integração dos serviços de comunicação, transporte e financeiros com a finalidade de atender às demandas do consumidor final. Estima-se que no estado do Espírito Santo, o consumo de carne de frango seja de 44,4 quilos per capita por ano. Para atender a esta demanda, o estado conta com matadouros-frigoríficos distribuídos pelo seu território, bem como, com a participação de outras empresas localizadas no país. Em sistemas de transportes, são característicos Problemas de Roteamento de Veículos (VRP), que precisam ser estudados, caracterizados e otimizados, normalmente, através de rotinas computacionais, que permitem avaliar maior quantidade de variáveis. O presente trabalho teve por objetivo caracterizar um VRP de um matadouro-frigorífico da região do Sul do Espírito Santo e desenvolver um aplicativo computacional que seja suporte para os gestores de logística, servindo para avaliar e propor rotas, e analisar parâmetros logísticos do processo de distribuição de produtos. No desenvolvimento do aplicativo computacional foi necessário caracterizar o sistema logístico da empresa, coletar e analisar os dados das operações logísticas, desenvolver as rotinas computacionais que representassem o sistema em estudo, verificar a confiabilidade dos resultados fornecidos pelo aplicativo, validá-lo e então, poder realizar as experimentações. O aplicativo desenvolvido permitiu reproduzir dados do sistema estudado e avaliar rotas segundo parâmetros logísticos. Pode-se concluir que o aplicativo computacional desenvolvido é útil aos gestores de logística, permitindo a avaliação das rotas praticadas e de novas configurações de rotas.

On the development of an automatic voice pleasantness classification and intensity estimation system

In the last few years, the number of systems and devices that use voice based interaction has grown significantly. For a continued use of these systems, the interface must be reliable and pleasant in order to provide an optimal user experience. However there are currently very few studies that try to evaluate how pleasant is a voice from a perceptual point of view when the final application is a speech based interface. In this paper we present an objective definition for voice pleasantness based on the composition of a representative feature subset and a new automatic voice pleasantness classification and intensity estimation system. Our study is based on a database composed by European Portuguese female voices but the methodology can be extended to male voices or to other languages. In the objective performance evaluation the system achieved a 9.1% error rate for voice pleasantness classification and a 15.7% error rate for voice pleasantness intensity estimation.

Despacho Económico de um SEE com coordenação Hidrotérmica Departamento de Engenharia Electrotécnica

O Despacho económico de um sistema eléctrico de energia com a coordenação hidrotérmica tem como objectivo alcançar a operação óptima do sistema em um determinado período de tempo, ao menor custo possível, e com alto grau de fiabilidade. O problema é muito complexo, pois depende do grau de dificuldade em se prever os caudais dos afluentes, e da capacidade das albufeiras das centrais hídricas. De um modo geral, a produção térmica é determinada de modo a proporcionar o uso mais racional possível da água, dentro do contexto de incertezas quanto às afluências futuras, de modo a, por um lado manter o sistemas o mais económico possível, e por outro, evitar o desperdício energético implícito em descarregamentos de volumes de água turbináveis. Neste trabalho é proposta uma metodologia baseada em programação linear para a solução da coordenação hidrotérmica de curto prazo, e que permite obter custos-sombra de água em centrais hídricas com armazenamento. Esta metodologia foi posteriormente implementado num programa computacional em Microsoft Excel 2010 para a solução numa primeira fase, da rede de 24 barramentos do IEEE, e numa segunda fase, para a solução da Rede Nacional de Transporte referente ao ano de 2010. Para efeitos de análise e validação de dados, os dados provenientes do programa, são depois comparados aos dados dos relatórios da REN. Por último, os dados provenientes do programa em Excel são colocados e analisados no programa PowerWorld Simulator 8.0.

Models and tools for value systems analysis in collaborative environments

Dissertation to obtain the degree of Doctor in Electrical and Computer Engineering, specialization of Collaborative Networks

Factors that Influence Adherence to Exercise among Patients Attending a Cardiac Rehabilitation Program

Objective: The aim of this study was to compare the factors of adherence to physical activity in subjects attending a cardiac rehabilitation program, and subjects who have withdrawal this same program using the Transtheoretical Model of behavior change. Methods: We conducted an observational, cross sectional type study, with a sample of 33 individuals (15 currently participating in the Cardiac Rehabilitation Program and 18 who no more attended the same program), with the questionnaires being personally delivered or sent by mail. For data analysis, we used the computer program SPSS® version 16.0. The significance level was set at 0.05. Results: There were no significant differences in the states of Change, Self-efficacy, Decisional Balance and Change Processes in both groups. We obtained a high Spearman correlation between States of Change and Self-efficacy (r2 = 0.778) and the Pros (r2 = 0.764) and Againsts (r2 = -0.744) in Decisional Balance. However, there were no significant evidence to affirm that States of Change and experiential processes of change (p = 0.465) andbehavioral (p = 0.300) had a correlation. A relationship was found, in terms of proportions between physical activity incorporated or not in a Cardiac Rehabilitation Program and age (p = 0.003), occupation (p = 0.010) and the entity paying the costs of program (p = 0.027). Conclusion: It was concluded that perceived self-efficacy and Pros and Againsts of the Decisional Balance are related to adherence to physical activity. Results also point out that age, profession and the entity paying the costs of the program influences the dropout of Cardiac Rehabilitation Programs.

Framework development for providing accessibility to qualitative spatial calculi

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.