El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / In the mining industry, the mining cycle is a very important part in the operating stage of every mining unit. Through the exploitation method used, the mining cycle provides mineral ore, which subsequently undergoes various metallurgical processes and its commercialization and thereby generates profits to the mining company. Currently, within this cycle, the hauling and transportation stages are those that have a lower efficiency with respect to the drilling and blasting stages. Therefore, the sector is always seeking effective ways to optimize these processes, reduce downtime and increase productivity. Six Sigma is a technique that allows for the continuous process improvement. In this study, the factors that generate inefficiency in the hauling cycle are determined, and alternatives are implemented to solve the main problem and improve the operations cycle.

No description available.

Made available in DSpace on 2016-07-27T14:20:21Z (GMT). No. of bitstreams: 1 MARCOS PAULO GOMES DE ARAUJO.pdf: 1260442 bytes, checksum: 955ac57258629e7d5991a3817f55a8ac (MD5) Previous issue date: 2014-03-14 / Among several motor skills training techniques, covert rehearsal (or covert practice, mental training, symbolic repetition, mental practice, mental rehearsal, imagined execution, visualization, mentalizing ) has been used to improve sportive performance. From a radical behaviorism perspective, imagining is conceived as covert behavior. To imagine is see something in the absence of the thing being seen, with this seeing in the absence analogous in nature to the seeing when the thing saw is present. Who is imagining, are not doing two different things in these two different situations, but the same thing. In this sense, imagining is behavior. The effect of covert rehearsal upon motor skills executions depends of variables such as the mode and/or context in which the technique is used. The objective of the present study was to verify the effect of training procedures composed by instructional variables and covert rehearsal technique upon the motor execution of the volleyball overhand serve. Eight (8) teenagers, both sexes (six [6] men), with ages between 13 and 15 years, regular basic level apprentices in a volleyball initiation course, served as experimental participants. Randomly distributed into three groups, all participants were exposed to four experimental conditions: Baseline (BL), Regular Training (RT), Instructed Covert Rehearsal Training (ICR) and Covert Rehearsal Training with a Model (CRM). Groups differ in the order of exposition to the conditions from the second one, with the BL as the first condition for all groups. In each condition, participants executed ten (10) overhand serves, everyone filmed by the experimenter. Thirteen (13) volleyball experts (judges) evaluated the last three (3) BL serves and the first three (3) serves executed after exposition to RT, ICR and CRM conditions. Executions filmed were presented randomly and judges used a specific protocol to evaluate and quantify serve adequacy, considering serves in four main components (initial position, ball throwing, ball attack and finalization). Statistical analyses to verify order effects showed that the different order expositions to the experimental conditions did not affect executions, with no significant differences observed between the three groups. Friedman variance analysis, with the experimental conditions data taken together, showed that, for 31,25% comparisons, significant differences were observed between BL executions and that after covert rehearsal conditions (specially, in the ICR condition, but in the CRM condition too), but in a minor percent between these conditions. Results were interpreted in terms of: 1) the developmental level of self-perceptive, verbal and motor repertoires of the apprentices trained, 2) the nature of the control that can be exerted by the instructional components in the covert rehearsal conditions and 3) the interrelation between verbal (speaker and listening behaviors) and perceptual (imagining) variables as related with motor performance. / Dentre as várias técnicas de treinamento de habilidades motoras, o ensaio encoberto (ou prática encoberta, treino mental, repetição simbólica, prática mental, ensaio mental, execução imaginada, visualização, mentalização) tem sido usada com o objetivo de melhorar o desempenho esportivo. Na perspectiva do behaviorismo radical, o imaginar é entendido como comportamento encoberto. Imaginar é ver algo na ausência da coisa vista, sendo este ver na ausência análogo em natureza ao ver quando o que se vê está presente. Quem imagina, não está fazendo duas coisas diferentes nas duas situações, mas a mesma coisa. Nesse sentido, imaginar é um comportamento. O efeito do ensaio encoberto sobre a execução de habilidades motoras depende de variáveis tais como o modo e/ou o contexto em que a técnica é utilizada. O objetivo do presente estudo foi verificar o efeito de treinamento composto por variáveis instrucionais e técnica de ensaio encoberto sobre a execução motora do saque por cima do voleibol. Oito (8) adolescentes, de ambos os sexos (6 homens), com idade variando entre 13 e 15 anos, alunos regulares de iniciação ao voleibol, serviram como participantes do experimento. Distribuídos aleatoriamente em três grupos, todos os participantes foram expostos a quatro condições experimentais: Linha de Base (LB), Treinamento Padrão (TP), Treinamento com Ensaio Encoberto Instruído (TEI) e Treinamento com Ensaio Encoberto com Modelo (TEM). Os grupos diferiram quanto à ordem de exposição às condições a partir da segunda, sendo a LB a primeira para todos os grupos. Em cada condição, os participantes executaram dez (10) saques, todos eles tendo sido filmados pelo experimentador. Treze (13) avaliadores peritos em voleibol avaliaram, assistindo aos filmes, a execução dos três (3) últimos saques da condição LB e a execução dos três (3) primeiros após a exposição às condições TP, TEI e TEM. Nos filmes, as execuções foram apresentadas em ordem aleatória e a avaliação foi feita a partir de protocolo específico para dimensionar a adequação do saque, a partir dos seus quatro componentes principais (posição inicial, lançamento da bola, ataque à bola e finalização). Análise estatística dos dados para verificar efeito de ordem de exposição às condições mostrou que tal efeito não ocorreu, não sendo significativas as diferenças entre os três grupos. Tomados os dados em conjunto por condição experimental, análise de variância de Friedman mostrou que, em 31,25% das comparações, diferenças significativas ocorreram entre as execuções em LB e aquelas pós-ensaios encobertos (em especial no TEI, mas também no TEM), mas em número bem menor entre as condições. Os resultados foram interpretados quanto: 1) ao nível de desenvolvimento dos repertórios auto perceptivo, verbal e motor dos aprendizes expostos aos treinamentos, 2) a natureza do controle que pode ser exercido pelos componentes instrucionais nas condições com ensaio encoberto e 3) a inter-relação entre variáveis verbais (comportamentos de falante e ouvinte) e perceptuais (imaginação) na relação com o desempenho motor.

Prevalence of physical inactivity in children and adolescents and the associated epidemic of obesity are increasing concerns. U.S. national health statistics indicate early adolescence (i.e., 10-14 years) appears to be a period of importance regarding physical activity, sedentary behavior, health-related physical fitness, and obesity trends. Considering a significant portion of their waking hours are spent in school, it is widely held that schools' should play a significant role in increasing students' physical activity and health-related physical fitness. To do this, physical education in schools focus on providing quality physical education programs that produce physically literate individuals who have the knowledge, skills, and confidence to enjoy a lifetime of health-producing physical activity. In effect, a call for developing a comprehensive and valid measure of physical literacy has been aptly expressed. Thus, the purpose of this dissertation was to test the psychometric properties of proposed models of physical literacy, examine correlates of the physical literacy factor, and investigate the significance of the relationship between physical literacy and interscholastic sport intention via structural equation modeling. Participants were 400 (231 female, 169 male) sixth-grade physical education students who completed three brief surveys assessing maturation, self-efficacy, self-esteem, knowledge and understanding, motivation, physical activity and sport participation, and interscholastic sport intention. In addition, students completed a sedentary behavior log, a health-related physical fitness assessment, and an overhand throwing skill assessment. Analyses offered overall support for the proposed physical literacy measurement models. Results also supported positive relationship Physical literacy was statistically significantly positively related physical activity and sport team participation, and significantly negatively related and screen-time sedentary behavior. Results also supported a positive path between physical literacy and interscholastic sport intention. The implications of promoting physical literacy within physical education are discussed in light of the three higher-order underlying factors of physical literacy.

科学研究費補助金 研究種目:一般研究(C)(2) 課題番号:07680107 研究代表者:櫻井 伸二 研究期間:1995-1996年度