990 resultados para numerical prediction
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Objective: To establish a prediction model of the degree of disability in adults with Spinal CordInjury (SCI ) based on the use of the WHO-DAS II . Methods: The disability degree was correlatedwith three variable groups: clinical, sociodemographic and those related with rehabilitation services.A model of multiple linear regression was built to predict disability. 45 people with sci exhibitingdiverse etiology, neurological level and completeness participated. Patients were older than 18 andthey had more than a six-month post-injury. The WHO-DAS II and the ASIA impairment scale(AIS ) were used. Results: Variables that evidenced a significant relationship with disability were thefollowing: occupational situation, type of affiliation to the public health care system, injury evolutiontime, neurological level, partial preservation zone, ais motor and sensory scores and number ofclinical complications during the last year. Complications significantly associated to disability werejoint pain, urinary infections, intestinal problems and autonomic disreflexia. None of the variablesrelated to rehabilitation services showed significant association with disability. The disability degreeexhibited significant differences in favor of the groups that received the following services: assistivedevices supply and vocational, job or educational counseling. Conclusions: The best predictiondisability model in adults with sci with more than six months post-injury was built with variablesof injury evolution time, AIS sensory score and injury-related unemployment.
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Non-specific Occupational Low Back Pain (NOLBP) is a health condition that generates a high absenteeism and disability. Due to multifactorial causes is difficult to determine accurate diagnosis and prognosis. The clinical prediction of NOLBP is identified as a series of models that integrate a multivariate analysis to determine early diagnosis, course, and occupational impact of this health condition. Objective: to identify predictor factors of NOLBP, and the type of material referred to in the scientific evidence and establish the scopes of the prediction. Materials and method: the title search was conducted in the databases PubMed, Science Direct, and Ebsco Springer, between1985 and 2012. The selected articles were classified through a bibliometric analysis allowing to define the most relevant ones. Results: 101 titles met the established criteria, but only 43 metthe purpose of the review. As for NOLBP prediction, the studies varied in relation to the factors for example: diagnosis, transition of lumbar pain from acute to chronic, absenteeism from work, disability and return to work. Conclusion: clinical prediction is considered as a strategic to determine course and prognostic of NOLBP, and to determine the characteristics that increase the risk of chronicity in workers with this health condition. Likewise, clinical prediction rules are tools that aim to facilitate decision making about the evaluation, diagnosis, prognosis and intervention for low back pain, which should incorporate risk factors of physical, psychological and social.
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Se realizó estudio cuasi experimental con el fin de comparar el efecto sobre la carga física de una intervención tecnológica y en la organización del trabajo en trabajadores en el cargo de horneros en la tarea de extracción de coque en Colombia. Se midió la carga física mediante frecuencia cardiaca e índice de costo cardiaco relativo en una población de trabajadores expuestos (37) y no expuestos (66) a una intervención tecnológica. La monitorización de la frecuencia cardiaca se realizó con 7 pulsímetros Polar RS 800cx debidamente calibrados. Las variables numéricas se describieron con base en la media aritmética, su desviación estándar, y el rango. Para evaluar la diferencia entre las medias de los grupos con respecto a la frecuencia cardiaca en reposo, media, máxima, índice de costo cardiaco relativo, gasto energético de trabajo se aplicó análisis de varianza de una vía. Se estableció a priori un nivel de significación estadística α = 0,05. Se encontraron diferencias estadísticamente significativas en el comportamiento de la frecuencia cardiaca media, frecuencia cardiaca máxima e índice de costo cardiaco relativo, entre los grupos de estudio. Se concluyó que este estudio valida la frecuencia cardiaca como una variable sensible para la medición del riesgo por carga física y a su utilidad en la evaluación intervenciones ergonómica. El estudio demostró que la intervención ergonómica logró controlar la carga física con una disminución significativa la frecuencia cardiaca, en el grupo de intervención.
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Se presenta el análisis de sensibilidad de un modelo de percepción de marca y ajuste de la inversión en marketing desarrollado en el Laboratorio de Simulación de la Universidad del Rosario. Este trabajo de grado consta de una introducción al tema de análisis de sensibilidad y su complementario el análisis de incertidumbre. Se pasa a mostrar ambos análisis usando un ejemplo simple de aplicación del modelo mediante la aplicación exhaustiva y rigurosa de los pasos descritos en la primera parte. Luego se hace una discusión de la problemática de medición de magnitudes que prueba ser el factor más complejo de la aplicación del modelo en el contexto práctico y finalmente se dan conclusiones sobre los resultados de los análisis.
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El libro presenta un conjunto de tests de aptitud (para medir el potencial de éxito de una persona) y tests de inteligencia normalizados, cada vez más utilizados en procesos de contratación, selección y evaluación de personal. Organizados en cuatro apartados, tests de aptitud verbal, espacial, numérica y tests de inteligencia, permiten trabajar distintas áreas (significado de palabras, gramática y comprensión, aptitud verbal avanzada, análisis lógico, cálculo mental, secuencias numéricas y problemas numéricos) para mejorar las habilidades verbales, numéricas y de razonamiento del lector.
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Resumen tomado de la publicaci??n
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Resumen tomado de la publicaci??n
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The control and prediction of wastewater treatment plants poses an important goal: to avoid breaking the environmental balance by always keeping the system in stable operating conditions. It is known that qualitative information — coming from microscopic examinations and subjective remarks — has a deep influence on the activated sludge process. In particular, on the total amount of effluent suspended solids, one of the measures of overall plant performance. The search for an input–output model of this variable and the prediction of sudden increases (bulking episodes) is thus a central concern to ensure the fulfillment of current discharge limitations. Unfortunately, the strong interrelation between variables, their heterogeneity and the very high amount of missing information makes the use of traditional techniques difficult, or even impossible. Through the combined use of several methods — rough set theory and artificial neural networks, mainly — reasonable prediction models are found, which also serve to show the different importance of variables and provide insight into the process dynamics
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A simple numerical model which calculates the kinetics of crystallization involving randomly distributed nucleation and isotropic growth is presented. The model can be applied to different thermal histories and no restrictions are imposed on the time and the temperature dependences of the nucleation and growth rates. We also develop an algorithm which evaluates the corresponding emerging grain-size distribution. The algorithm is easy to implement and particularly flexible, making it possible to simulate several experimental conditions. Its simplicity and minimal computer requirements allow high accuracy for two- and three-dimensional growth simulations. The algorithm is applied to explore the grain morphology development during isothermal treatments for several nucleation regimes. In particular, thermal nucleation, preexisting nuclei, and the combination of both nucleation mechanisms are analyzed. For the first two cases, the universal grain-size distribution is obtained. The high accuracy of the model is stated from its comparison to analytical predictions. Finally, the validity of the Kolmogorov-Johnson-Mehl-Avrami model SSSR, is verified for all the cases studied
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In this thesis I propose a novel method to estimate the dose and injection-to-meal time for low-risk intensive insulin therapy. This dosage-aid system uses an optimization algorithm to determine the insulin dose and injection-to-meal time that minimizes the risk of postprandial hyper- and hypoglycaemia in type 1 diabetic patients. To this end, the algorithm applies a methodology that quantifies the risk of experiencing different grades of hypo- or hyperglycaemia in the postprandial state induced by insulin therapy according to an individual patient’s parameters. This methodology is based on modal interval analysis (MIA). Applying MIA, the postprandial glucose level is predicted with consideration of intra-patient variability and other sources of uncertainty. A worst-case approach is then used to calculate the risk index. In this way, a safer prediction of possible hyper- and hypoglycaemic episodes induced by the insulin therapy tested can be calculated in terms of these uncertainties.
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La feina feta en aquest treball de tesis s'ha desenvolupat a partir de tres objectius vertebradors, que fonamentalment són: ·El primer dels objectius d'aquest treball de tesis és presentar un recull dels factors que intervenen en l'acústica urbanística: soroll produït pels diferents vehicles, fórmules de predicció de soroll, geometria dels edificis... , tot estudiant els seus efectes en la ciutat de Girona. ·Un altre objectiu ha estat desenvolupar uns mètodes numèrics propis, contrastats experimentalment i extrapolables a qualsevol entorn urbanístic, que permetin predir els valors de les pertorbacions acústiques produïdes pels diferents vehicles en diferents situacions, entre els que es destaquen: -Fórmula de predicció del soroll en un entorn urbà i la seva aplicació a Girona. -Càlcul de l'increment de soroll en un carrer provocat per les reflexions de les ones sonores en les façanes dels edificis. -Estudi del nivell de soroll en la boca de la cavitat d'un túnel produït pel pas del ferrocarril. -Determinació del soroll provocat pel pas d'un tren sobre un viaducte. -Mètode de distribució i planificació del trànsit urbà per disminuir l'impacte acústic sobre la zona. ·El darrer objectiu consisteix en fer una descripció analítica de les principals fonts de soroll que afecten a la ciutat: el trànsit viari i el ferrocarril. Per realitzar aquests objectius s'ha disposat d'un banc de dades amb més de 2.000 mesures sonores de Girona (nivells equivalents de 10 minuts de durada). La metodologia seguida i els principis en que es fonamenta es detallen a l'inici de cada apartat. La finalitat de tots aquests estudis, no és altre que millorar el confort acústic, i la qualitat de vida, de les ciutats. Gairebé tots els grans nuclis de població del planeta es veuen afectats per una gravíssima problemàtica mediambiental, doncs a l'anomenada contaminació acústica cal afegir uns alts índexs de pol·lució atmosfèrica (altes concentracions de biòxid de carboni, generació d'illes de calor...). Aquesta situació, generalitzada arreu del planeta, ha propiciat l'aparició de mesures dràstiques consistents fonamentalment en restringir l'accés dels vehicles motoritzats als nuclis i zones centrals de les àrees urbanes. Precisament aquesta opció s'ha proposat per les zones interiors de Girona on l'elevada densitat de les edificacions deixa un escàs marge per plantejar la construcció de noves rutes o vies alternatives. Cal esmentar que tots els càlculs i teories que es desenvolupen en aquest treball de tesis reflecteixen la realitat acústica actual provocada pels diferents mitjans de transport. Molt possiblement, en un futur no massa llunyà, els nivells de soroll (dB) enregistrats en situacions de tràfic similar seran força menors. Són molts els factors que poden contribuir a aquesta disminució de la intensitat de les emissions sonores: reducció del fregament mecànic, augment del coeficient aerodinàmic, nous materials pels pneumàtics i l'asfalt ... Sense cap mena de dubte, però, una millora transcendental, i no només pel que fa al confort acústic sinó per l'ecosistema en general, seria potenciar la construcció de motors elèctrics o d'hidrogen. Aquests últims per exemple, a diferència dels motors de combustió, funcionen mitjançant piles de combustible que converteixen, amb molta netedat, el gas hidrogen en electricitat i possibiliten l'existència de vehicles no contaminants propulsats per motors elèctrics menys sorollosos. Així, al haver-hi menys fregament entre les parts mòbils del motor (no hi ha pistons ni cilindres) el soroll generat es reduiria considerablement.
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Silvicultural treatments have been shown to alter the composition of species assemblages in numerous taxa. However, the intensity and persistence of these effects have rarely been documented. We used a before-after, control-impact (BACI) paired design, i.e., five pairs of 25-ha study plots, 1-control and 1-treated plot, to quantify changes in the density of eight forest bird species in response to selection harvesting over six breeding seasons, one year pre- and five years postharvest. Focal species included mature forest associates, i.e., Northern Parula (Setophaga americana) and Black-throated Green Warbler (Setophaga virens), forest generalists, i.e., Yellow-bellied Sapsucker (Sphyrapicus varius) and Swainson’s Thrush (Catharus ustulatus), early-seral specialists, i.e., Mourning Warbler (Geothlypis philadelphia) and Chestnut-sided Warbler (Setophaga pensylvanica), species associated with shrubby forest gaps, i.e., Black-throated Blue Warbler (Setophaga caerulescens), and mid-seral species, i.e., American Redstart (Setophaga ruticilla). As predicted, we found a negative numerical response to the treatment in the Black-throated Green Warbler, no treatment effect in the Yellow-bellied Sapsucker, and a positive treatment effect in early-seral specialists. We only detected a year effect in the Northern Parula and the American Redstart. There was evidence for a positive treatment effect on the Swainson’s Thrush when the regeneration started to reach the pole stage, i.e., fifth year postharvest. These findings suggest that selection harvesting has the potential to maintain diverse avian assemblages while allowing sustainable management of timber supply, but future studies should determine whether mature-forest associates can sustain second- and third-entry selection harvest treatments.
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A new method for assessing forecast skill and predictability that involves the identification and tracking of extratropical cyclones has been developed and implemented to obtain detailed information about the prediction of cyclones that cannot be obtained from more conventional analysis methodologies. The cyclones were identified and tracked along the forecast trajectories, and statistics were generated to determine the rate at which the position and intensity of the forecasted storms diverge from the analyzed tracks as a function of forecast lead time. The results show a higher level of skill in predicting the position of extratropical cyclones than the intensity. They also show that there is potential to improve the skill in predicting the position by 1 - 1.5 days and the intensity by 2 - 3 days, via improvements to the forecast model. Further analysis shows that forecasted storms move at a slower speed than analyzed storms on average and that there is a larger error in the predicted amplitudes of intense storms than the weaker storms. The results also show that some storms can be predicted up to 3 days before they are identified as an 850-hPa vorticity center in the analyses. In general, the results show a higher level of skill in the Northern Hemisphere (NH) than the Southern Hemisphere (SH); however, the rapid growth of NH winter storms is not very well predicted. The impact that observations of different types have on the prediction of the extratropical cyclones has also been explored, using forecasts integrated from analyses that were constructed from reduced observing systems. A terrestrial, satellite, and surface-based system were investigated and the results showed that the predictive skill of the terrestrial system was superior to the satellite system in the NH. Further analysis showed that the satellite system was not very good at predicting the growth of the storms. In the SH the terrestrial system has significantly less skill than the satellite system, highlighting the dominance of satellite observations in this hemisphere. The surface system has very poor predictive skill in both hemispheres.