Active Learning and Dynamic Pricing Policies

In this paper, we address the problem of dynamic pricing to optimize the revenue coming from the sales of a limited inventory in a finite time-horizon. A priori, the demand is assumed to be unknown. The seller must learn on the fly. We first deal with the simplest case, involving only one class of product for sale. Furthermore the general situation is considered with a finite number of product classes for sale. In particular, a case in point is the sale of tickets for events related to culture and leisure; in this case, typically the tickets are sold months before the event, thus, uncertainty over actual demand levels is a very a common occurrence. We propose a heuristic strategy of adaptive dynamic pricing, based on experience gained from the past, taking into account, for each time period, the available inventory, the time remaining to reach the horizon, and the profit made in previous periods. In the computational simulations performed, the demand is updated dynamically based on the prices being offered, as well as on the remaining time and inventory. The simulations show a significant profit over the fixed-price strategy, confirming the practical usefulness of the proposed strategy. We develop a tool allowing us to test different dynamic pricing strategies designed to fit market conditions and seller s objectives, which will facilitate data analysis and decision-making in the face of the problem of dynamic pricing

Implementación de una infraestructura como servicio para desarrollo de prácticas SDN y NFV

Desplegar una infraestructura como servicio SDN utilizando herramientas de virtualización y computación en la nube para la realización de prácticas SDN/NFV en redes virtualizadas para la carrera de Telecomunicaciones.El presente trabajo expone el desarrollo de una infraestructura como servicio, la cual está basada en tecnologías de computación en la nube utilizando OpenStack, la misma tiene como propósito, brindar a los estudiantes de la carrera de Telecomunicaciones de la Universidad Técnica del Norte un sistema de instancias virtuales para el desarrollo de prácticas en tecnologías SDN y NFV. En el análisis situacional actual, mostro la existencia de problemas al momento que los estudiantes realizan prácticas o laboratorios, debido a los altos requerimientos que presentan los softwares a utilizar al simular ambientes de tecnologías SDN y NFV. Por este motivo el presente proyecto presenta una solución donde la carga de procesamiento es relevada hacia un servidor externo, mismo que presta instancias virtuales, con todas las herramientas y servicios ya instalados, de manera que el estudiante pueda realizar sus actividades, de manera remota inmediatamente. Los resultados obtenidos en el proyecto indican que su aplicación en la carrera de Telecomunicaciones facilitará el aprendizaje y desarrollo de las tecnologías SDN y NFV, debido a su conveniencia de implementación eliminando la necesidad de la instalación de todos los servicios y aplicaciones requeridas en el dispositivo personal, ya que la instancia virtual presenta las mismas herramientas y servicios ya instalados y listos para utilizar bajo demanda del estudiante.Ingenierí

Timber Specimens Parametrized Design for Numerical Analysis

[Abstract] The characterization of materials or the study of resistant response associated with new constructive solutions often convey progressive adjustment of models of analysis starting from the results obtained by means of test campaigns. The reliability of the conclusions will obviously be conditioned by the amplitude of the experimental development which, as a result, should contain a sufficiently representative sampling of cases. In the situations where significantly multiple parameters intervene, specimens that involve possible values and combinations should be examined, which in practice remarkably increases the number of specimens to be treated. The case being presented deals with the evaluation of the effectiveness of certain fixed joints carried out by gluing metallic bars into timber pieces by means of adhesives of different formulations. The set of calculus patterns, including the extensive variability of the associated magnitudes, has been treated in a parametrized form. The geometry of the studied pieces, as well as the sustenance conditions and the load, are automatically generated by means of software specially designed for those purposes. The resulting information is structured in an orderly way to facilitate its reading and also its manipulation if needed. The files of the process obtained in this way can optionally incorporate the meshing sequences, as well as the commands of the calculus, analysis and postprocess. The adopted strategy considerably reduces the time assigned to the phases of the geometrical definition and resolution, and enormously simplifies the interpretation of the results

Status and Dietary Intake of Phytoene and Phytofluene in Spanish Adults and the Effect of a Four-Week Dietary Intervention with Lutein-Rich Fruits or Vegetables.

Phytoene (PT) and phytofluene (PTF) are colourless carotenoids presents in the human diet and in blood, faeces and tissues and are biologically active. However, there is very little data on these carotenoids. This study aims to assess PT and PTF concentrations in serum from healthy Spanish normolipemic subjects (n = 101, 45–65 years) and the effect of a fruit and vegetable dietary intervention (4 weeks, n = 29) on PT and PTF concentration in serum and faeces and dietary intake. Serum and faecal concentrations were analysed by HPLC and dietary intake by 3 × 24 h recalls. PT showed higher concentrations than PTF in serum, faeces and in the dietary intake. Considering both studies, PT and PTF concentrations in serum were 0.16 ± 0.07 and 0.05 ± 0.04 µmol/L, respectively, in faeces 17.7 ± 20.3 and 6.5 ± 7.9 µg/g, respectively, and in dietary intake the median was 2.4 and 0.6 mg/p/day, respectively. Carrots and tomatoes were the major dietary contributors of these carotenoids. The dietary intervention did not cause significant variations in the PT and PTF intake or serum concentrations, but a lower concentration in faeces was observed for the fruit group (PT: p = 0.024; PTF isomer-3: p = 0.034). These data highlight the need for further research on the activities of these carotenoids in humanspost-print1648 K

Dietary β-Cryptoxanthin and α-Carotene Have Greater Apparent Bioavailability Than β-Carotene in Subjects from Countries with Different Dietary Patterns.

β-carotene, α-carotene and β-cryptoxanthin are greater contributors to vitamin A intake than retinol in the human diet for most people around the world. Their contribution depends on several factors, including bioavailability and capacity of conversion into retinol. There is an increasing body of research showing that the use of retinol activity equivalents or retinol equivalents could lead to the underestimation of the contribution of β-cryptoxanthin and of α-carotene. The aim is to assess their apparent bioavailability by comparing concentrations in blood to their dietary intakes and identifying the major food contributors to their dietary intake. Dietary intake (3-day 24-h records) and serum concentrations (by HPLC) were calculated in normolipemic subjects with adequate retinol status (≥1.1 µmol/L) from our studies (n = 633) and apparent bioavailability calculated from 22 other studies (n = 29,700). Apparent bioavailability was calculated as the ratio of concentration in the blood to carotenoid intake. Apparent bioavailabilities for α-carotene and β-cryptoxanthin were compared to those for β-carotene. Eating comparable amounts of α-carotene, β-cryptoxanthin and β-carotene foods resulted in 55% greater α-carotene (95% CI 35, 90) and 686% higher β-cryptoxanthin (95% CI 556, 1016) concentrations than β-carotene in blood. This suggests differences in the apparent bioavailability of α-carotene and β-cryptoxanthin and even larger differences with β-cryptoxanthin, greater than that of β-carotene. Four fruits (tomato, orange, tangerine, red pepper) and two vegetables (carrot, spinach) are the main contributors to their dietary intake (>50%) in Europeans.post-print579 K

Módulo didáctico de los inyectores del sistema COMMON RAIL de la camioneta Volkswagen Amarok.

Módulo didáctico sobre los inyectores del sistema Common Rail de la camioneta Volkswagen Amarok.Este presente trabajo trata sobre la elaboración de un módulo didáctico sobre los inyectores del sistema Common Rail de la camioneta Volkswagen Amarok, a medida que se realiza este módulo se da una oportunidad de aprendizaje, en el cual los docentes y estudiantes de la carrera y de toda la universidad podrán adquirir conocimientos sobre el inyector piezoeléctrico del sistema common rail, de tal manera que puedan aprender de forma didáctica y practica dicho sistema. Para la realización de este trabajo se desarrolló un marco teórico definido al tema de inyector piezoeléctrico el cual nos ayuda a comprender de mejor manera la teoría y el funcionamiento del inyector CRDi. El modulo didáctico está constituido de dos unidades las cuales tienen una parte teórica y una parte donde se indica el mantenimiento del inyector y también tiene actividades y evaluaciones relacionadas a cada unidad. En la primera unidad describiremos el inyector piezoeléctrico de la camioneta Amarok tanto su estructura, componentes y el funcionamiento del mismo, siendo esta unidad la más teórica del módulo didáctico. La segunda unidad se da a conocer la clase de mantenimiento que se le da al inyector de tal manera que se pueda realizar un correcto mantenimiento del mismo, donde se realiza diferentes pruebas como la de volumen y retorno de combustible donde se verifica la clase de pulverización y se mide el desgate del cuerpo tobera-aguja mediante la entrega y retorno de combustible en el banco de pruebas, siendo esta unidad compuesta por conocimientos de mantenimiento y desarrollando dichos conocimientos de forma didáctica y práctica para los estudiantes. Este módulo permite al docente luego de cada unidad realizar actividades didácticas que el estudiante deberá realizar en contacto con la camioneta Amarok que se encuentra a disposición en el taller de la carrera, y más aún ya que cuenta el laboratorio con el banco de pruebas para los inyectores piezoeléctricos del sistema common rail CRDi.Ingenierí