On The Three-Receiver Multilevel Broadcast Channel with Random Parameters

In this paper we extend the analysis of tworeceiver broadcast channels with random parameters to the three-receivers case. Specifically we base our work on Nair and El Gamal's results for the three-receiver discrete memoryless multilevel broadcast channel and assume that state information is available non-causally at the transmitter.We provide an achievable rate region for this setting and acknowledge its importance in the study of multiuser cognitive radio configurations

The introduction of the Africanised honey bee: A stinging menace or a blessing of the Americas? : a comparison of the Brazilian and USA beekeeping experiences

In 1956, Brazilian scientist Warwick Estevam Kerr, introduced queens of the African honey bee (AHB) from South Africa to breed with European honey bees (EHB) in order to improve honey production in Brazil. Some of the AHB swarmed by accident out of the experimental apiary, located in Rio Claro-São Paulo State, and started to spread. Today, these have mixed with EHB and exist all over Brazil, the Neo tropic of South America, Central America, and South USA. This situation created drastic changes in the management of bees across the region. This research explores and analyses the effects of the spreading of AHB in the social, economic, and policy-making levels in the apiculture sector in Brazil and USA. The study also contrasts and discusses the challenges faced by beekeepers in both countries and the resulting adaptation strategies to manage this new species. One of the most important results in economic terms was the gradual increase in honey production years after the introduction of Africanised bees to Brazil; On the other hand, in the United States, the introduction did not cause any alteration in beekeeping in the already declining production of honey. In contrast, free market policies, inadequate handling of bees, diseases, inadequate use of pesticides among other factors have contributed to the fall in honey production and the number of boxes of bees for decades. Another result in the social field was the constitution of an interstate organisation of beekeepers allowing beekeepers to organise congresses and conferences with the purpose of discussing, analysing and proposing joint solutions to the emerging threat of Africanised bees as well as seeking new technologies for their management as well as government support to fund apiculture enterprises. In general terms, the introduction of the Africanised in the medium and long term turned out to be a blessing instead of a threat to Brazilian apiculture and the rest of the Americas. However, in the United States, before and during colonisation, Africanised bees were seen as a threat to the beekeeping system, a vision that was dissipated as beekeepers became informed and found the best way to face the threat of Africanised bees, but with a problem still unsolved what will happen to the Africanised bees that for more than 20 years are already in the United States as swarms around the apicultural areas

Control of an over-actuated nanopositioning system by means of control allocation

This Master’s Thesis is devoted to the analysis and design of a control structure for the nanopositioning system LAU based on the dynamic control allocation technique. The objective is to control the vertical displacement with nanometer precision under a control effort distribution criterion among the actuator set. In this case, the pneumatic actuator is used as a passive gravity compensator while the voice coil motor generates the transient forces. The analysis of the system characteristics allows defining the design criterion for the control allocation. In this direction, the proposed dynamic control allocation stage considers a frequency distribution of the control effort. The lower frequency components are assigned to the pneumatic actuator while the higher frequencies are handled by the voice coil drive. The significant actuator dynamics are compensated through a Kalman filter approach. The position controller is based on a feedback linearization framework with a disturbance observer for enhanced robustness. The experimental validation demonstrates the feasibility of the proposed technique.Diese Masterarbeit widmet sich der Analyse und dem Entwurf einer Regelungsstruktur für das Nanopositioniersystem LAU. Dabei werden Methoden untersucht, welche das notwendige Stellsignal auf zwei Aktoren aufteilen. Ziel ist es, die vertikale Verschiebung des LAU mit Nanometerpräzision zu regeln. In diesem Fall wird der pneumatische Aktor als passiver Schwerkraftkompensator verwendet, während die elktromagnetische Tauchspule die transienten Kräfte erzeugt. Die Analyse der Eigenschaften des LAUSystems ermöglicht die Definition der Entwurfskriterien zur Aufteilung der Stellgröße. In dieser Richtung berücksichtigt die vorgeschlagene dynamische Methode eine Aufteilung der Stellgröße bezüglich der Frequenzanteile. Die niederfrequenten Komponenten werden dem pneumatischen Aktor zugeordnet. Dem elektromagnetische Aktor werden die verbliebenen hochfrequenten Anteile zugeordnet. Die signifikanten Effekte der Aktordynamik in Bezug auf die Bewegungsdynamik werden durch einen Kalman- Filteransatz kompensiert. Nichtlineare Streckenanteile werden basierend auf dem Modell und einem Störbeobachter kompensiert, sodass der verbleibende Anteil des Positionsreglers mit linearen Methoden entworfen werden kann. Die experimentelle Validierung zeigt die Effektivität des untersuchten Konzeptes.Tesi

Monitoreo de la Deforestacion en las Provincias de Huallaga, el Dorado y Lamas ; en el departamento de San Martin

The present thesis, "Monitoreo ofthe Deforestation in the provinces ofHuallaga, the Gilded one and You lick in the Department ofSan Martín", is oriented to contribute with the planning of the occupation of the territory and the use of the natural resources, in special with the process of Ecological and Economic Zonificación of the Region San Martín who the Institute of Investigations of the Peruvian Amazonía and the Regional Government of San Martín come promoting in our region. This work was made in arder to identify and to quantify the advance of the deforestation in the natural forests in the provinces of Huallaga, the Gilded one and You lick, in the department of San Martín; by means of the use of space indicators of the changes in the forest cover, using the Systems of Remate Perception (Teledetección) and the GIS (SIGs), as well as to identify and/or to describe the socioeconomic processes that detennine such process, besides to identify as it is the tendency of the advance of the deforestation in the area of intluence ofthe study. For the analysis it was used images of satellite Landsat TM5 and Landsat TM7, that date from the year of 1986 and 1999. These images were, previously corrected geometrically and treated specially for their later analysis. The analysis was visual optician or (digital format) directly of the screen using images in format of paper like support for the characterization of the units. For the field verification a fast sounding was made, registering sorne types of cover and Earth use in conventional photographies. The results are presented/displayed in images of satellite and maps of changes of the vegetal cover and patterns of use of the Earth as well as in maps of deforestation, for both years and map of evolution ofthe deforestation in a lapse of 13 years. One includes pictures and graphs as well as a matrix of changes those that facilitate the interpretation of the results. The study area, this conformed by the province of Huallaga that has a surface of 236.126 you have and it is located in the central and western part of the Region San Martín and almost occupies the totality of the river basin of the Saposoa river and the high river basin of the Huayabamba river; the province of the Gilded one that has a surface of 131.933 you have and it is located in the North and Western part of the Region San Martín; and the province of You lick that it has a surface of 501.056 you ha ve and is located in the North part of the Region San Martín. These three provinces altogether have a surface of 869.115 you have what represents 17,23 % of the territory of the Region. The economic base of this territory is the agriculture of subsistence, cattle ranch and the forest activity. lt was gotten to determine that the surface deforested in the provmce of Huallaga, in the lapse of the time of study, was of 30.440,92 you ha ve, with an annual rate of 1,64%, and mainly with farming aims, it is to say; subsistence agriculture (29.63%); in the province of the Gilded one, it was of 14.807,03 you have, with an annual rate of 1,54%, and also with aims of subsistence (54.77%); whereas in the province of You lick the intervention was of 41.889,96 you have, being 32,48% with farming aims, registering an annual rate of only 0.90%. These processes are fundamental consequence of one disordered occupation of the territory. The common denominator in the three provinces that form the study area is that, the deforestation pattem is massive or mosaic type in the zones of greater population and sorne zones where limitantes physicists exist or where the population is Iittle, the deforestation pattem is of linear type; in addition their economies are sustained in the subsistence agriculture, that includes bread cultures fundamentally to take (maize, frijol, rice, yucca, banana), complemented with agro-industrial cultures ( coffee, cacao, tobacco), fiuit trees (citric, papaya, fragmentation hand grenade), among others. Another activity is the cattle ranch that is carried out applying only sorne techniques essential to manage to maintain an suitable Earth use by lack of arboreal cover, giving rise to that the grounds, which they are highly vulnerable, are exposed to sorne way of erosion, impoverishment, risk of tloods in sorne cases, among others. And finally we have the forest activity like is the wood extraction, that is not considered like inaintained economy since at the present time this heading does not count on an ~luation of the logable volume to lack forest inventaries, since in lands of forest ap~itude and protection at the moment they are occupied in its majority by agricultura! activities. Two future scenes have been analyzed. In the tendencial scene it is anticipated, rhat to continue the same rate of deforestation of last the 13 years, the province of Huallaga will be of forestada in 40 years approximately, the province of the Gilded one in 09 years and the province of You tick approximately in 60 years, worsening the conditions of poverty, the loss of biodiversity and in general still more the environmental problems. However in scene wished, that it implies the ordered process of the occupation of the territory of the three provinces that cover the area with study, esteem that the intervention will be made only in areas with farming vocation, and in the areas with forest vocation projects of sustainable forest handling will be being been developing; in addition it is also anticipated that in this one scene it is managed to trigger a process of sustainable development, is increased the Earth productivity, improves the well-being of the population, the biological diversity is conserved and the atmosphere is preserved. The implementation is recommended in addition to a plan of territorial ordering for each one of the provinces that conform the study area, with base in the Ecological and Economic Zonificación of the Region San Martín; as well as to make the monitoreo of the deforestation at least every two years, in order to come up or to mitigate, according to is the case, the negative effects of the deforestation process.La presente tesis, "Monitoreo de la Deforestación en las pr0l1incias de Huallaga, El Dorado y Lamas en el Departamento de San Martín", está orientado a contribuir con la planificación de la ocupación del territorio y el uso de los recursos naturales, en especial con el proceso de Zonificación Ecológica y Económica de la Región San Martín que el Instituto de Investigaciones de la Amazonía Peruana y el Gobierno Regional de San Martín vienen promoviendo en nuestra región. Este trabajo se realizó con el propósito de identificar y cuantificar el avance de la deforestación en los bosques naturales en las provincias de Huallaga, El Dorado y Lamas, en el departamento de San Martín; mediante el uso de indicadores espaciales de los cambios en la cobertura forestal, utilizando los Sistemas de Percepción Remota (Teledetección) y los Sistemas de Información Geográfica (SIGs), así como identificar y/o describir los procesos socio-económicos que determinan tal proceso, además de identificar cual es la tendencia del avance de la deforestación en el área de influencia del estudio. Para el análisis se utilizó imágenes de satélite Landsat TMS y Landsat TM7, que datan del año de 1986 y 1999. Estas imágenes fueron, previamente corregidas geométricamente y tratadas especialmente para su posterior análisis. El análisis fue óptico o visual (formato digital) directamente de la pantalla utilizando imágenes en formato de papel como apoyo para la caracterización de las unidades. Para la verificación de campo se realizó un sondeo rápido, registrándose algunos tipos de cobertura y uso de la tierra en fotografias convencionales. Los resultados son presentados en imágenes de satélite y en mapas de cambios de la cobertura vegetal y patrones de uso de la tierra así como en mapas de deforestación, para ambos años y mapa de evolución de la deforestación en un lapso de 13 años. Se incluye cuadros y gráficos así como una matriz de cambios los que facilitan la interpretación de los resultados. El área de estudio, esta conformada por la provincia de Huallaga que tiene una superficie de 236, 126 has. y se ubica en la parte central y occidental de la Región San Martín y ocupa casi la totalidad de la cuenca del río Saposoa y la cuenca alta del río Huayabamba; la provincia de El Dorado que tiene una superficie de 131, 933 has. y se ubica en la parte Norte y Occidental de la Región San Martín; y la provincia de Lamas que tiene una superficie de 501,056 has. y se ubica en la parte Norte de la Región San Martín. Estas tres provincias en conjunto tienen una superficie de 869, 1 l 5 has. lo que representa el 17.23 % del territorio de la Región. La base económica de este territorio es la agricultura de subsistencia. ganadería y la actividad forestal. Se llegó a determinar que la superficie deforestada en la provincia de Huallaga. en el lapso del tiempo de estudio, fue de 30.440.92 has .. con una tasa anual de 1.64%, y principalmente con fines agropecuarios. es decir; agricultura de subsistencia (29.63%); en la provincia de El Dorado, fue de 14,807.03 has., con una tasa anual de 1.54%, y también con fines de subsistencia (54.77%); mientras que en la provincia de Lamas la intervención fue de 41,889. 96 has .. siendo un 32.48% con fines agropecuarios, registrando una tasa anual de solamente 0.90%. Estos procesos son consecuencia fundamental de una desordenada ocupación del territorio. El común denominador en las tres provincias que forman el área de estudio es que. el patrón de deforestación es masivo o tipo mosaico en las zonas de mayor población y en algunas zonas donde existen limitantes fisicos o donde la población es escasa, el patrón de deforestación es de tipo lineal; además sus economías se sustentan en la agricultura de subsistencia, que incluye fundamentalmente cultivos de pan llevar (maíz. frijol, arroz, yuca, plátano). complementado con cultivos agroindustriales (café, cacao, tabaco), frutales (cítricos, papaya, pii'\a,), entre otros. Otra actividad es la ganadería que se lleva a cabo aplicando sólo algunas técnicas imprescindibles para lograr mantener un uso adecuado de la tierra por falta de cobertura arbórea, dando lugar a que los suelos, que son altamente vulnerables. estén expuestos a alguna forma de erosión, empobrecimiento, riesgo de inundaciones en algunos casos, entre otras. Y por último tenemos la actividad forestal mediante la extracción de madera, que no es considerada como economía sostenida ya que en la actualidad este rubro no cuenta con una evaluación del volumen maderable por carecer de inventarios forestales, puesto que en los terrenos de aptitud forestal y de protección son actualmente ocupados en su mayoría por actividades agrícolas. Se han analizado dos escenarios futuros. En el escenario tendencia! se prevé, que de continuar el mismo ritmo de deforestación de los últimos 13 años, la provincia de Huallaga será deforestada en 33 años aproximadamente, la provincia de El Dorado en 09 años y la provincia de Lamas en 60 años aproximadamente, agudizando aún más las condiciones de pobreza, la pérdida de biodiversidad y en general los problemas ambientales. Empero en el escenario deseado, que implica el proceso ordenado de la ocupación del territorio de las tres provincias que cubren el área de estudio, se estima que la intervención se realizará sólo en áreas con vocación agropecuaria, y en las áreas con vocación forestal se estarán desarrollando proyectos de manejo forestal sostenible; además se prevé también que en éste escenario se logre desencadenar un proceso de desarrollo sostenible, se incremente la productividad de la tierra, se mejore el bienestar de la población, se conserve la diversidad biológica y se preserve el ambiente. Se recomienda además la implementación de un plan de ordenamiento territorial para cada una de las provincias que conforman el área de estudio, con base en la Zonificación Ecológica y Económica de la Región San Martín; así como realizar el monitoreo de la deforestación por lo menos cada dos años, con el propósito de prevenir o mitigar, según sea el caso, los efectos negativos del proceso de deforestación.Tesi

Mining Social and Affective Data for Recommendation of Student Tutors

This paper presents a learning environment where a mining algorithm is used to learn patterns of interaction with the user and to represent these patterns in a scheme called item descriptors. The learning environment keeps theoretical information about subjects, as well as tools and exercises where the student can put into practice the knowledge gained. One of the main purposes of the project is to stimulate collaborative learning through the interaction of students with different levels of knowledge. The students' actions, as well as their interactions, are monitored by the system and used to find patterns that can guide the search for students that may play the role of a tutor. Such patterns are found with a particular learning algorithm and represented in item descriptors. The paper presents the educational environment, the representation mechanism and learning algorithm used to mine social-affective data in order to create a recommendation model of tutors

Finanzas

Las finanzas corresponden a un área de la economía que estudia la obtención y administración del dinero y el capital, es decir, los recursos financieros. Estudia tanto la obtención de esos recursos (financiación), así como la inversión y el ahorro de los mismos. Las finanzas estudian cómo los agentes económicos (empresas, familias o Estado) deben tomar decisiones de inversión, ahorro y gasto en condiciones de incertidumbre. Al momento de elegir, los agentes pueden optar por diversos tipos de recursos financieros tales como: dinero, bonos, acciones o derivados, incluyendo la compra de bienes de capital como maquinarias, edificios y otras infraestructuras. Ver diferencia entre ahorro e inversión. Los intermediarios financieros son los agentes dedicados a poner en contacto las dos partes de las finanzas, los ahorradores y los que necesitan financiación. Las finanzas ayudan a controlar los ingresos y gastos, tanto al Gobierno, a las empresas, como a cada uno de nosotros. Tener un buen control de las finanzas nos permite gestionar mejor nuestros recursos, conociendo al detalle todos los ingresos y gastos, para tener un mayor control sobre ellos mismos

Deterministic coherence resonance in coupled chaotic oscillators with frequency mismatch

A small mismatch between natural frequencies of unidirectionally coupled chaotic oscillators can induce coherence resonance in the slave oscillator for a certain coupling strength. This surprising phenomenon resembles “stabilization of chaos by chaos,” i.e., the chaotic driving applied to the chaotic system makes its dynamics more regular when the natural frequency of the slave oscillator is a little different than the natural frequency of the master oscillator. The coherence is characterized with the dominant component in the power spectrum of the slave oscillator, normalized standard deviations of both the peak amplitude and the interpeak interval, and Lyapunov exponents. The enhanced coherence is associated with increasing negative both the third and the fourth Lyapunov exponents, while the first and second exponents are always positive and zero, respectively

La educación ambiental en la sociedad globalizada

La globalización ha supuestos cambios importantes en nuestra sociedad, incrementado el desequilibrio entre los países ricos y pobres, tanto desde el punto de vista económico como ambiental. La educación ambiental puede ser un instrumento para paliar estos desequilibrios, ya que la concienciación de nuestra sociedad puede influir en el consumo y este a su tiene efectos sobre la producción de bienes y servicios. En el artículo se muestran algunos ejemplos de la influencia de la concienciación ciudadana en los sistemas de producción

WILLINGNESS TO PAY FOR ENVIRONMENTAL SERVICES AMONG SLASH-AND-BURN FARMERS IN THE PERUVIAN AMAZON: IMPLICATIONS FOR DEFORESTATION AND GLOBAL ENVIRONMENTAL MARKETS

A Contingent Valuation survey shows that the possibility of trade in carbon sequestration services exists between utility companies and slash-and-burn farmers in the Amazon and that farmers positively value the environmental services of the forest. Global environmental markets could enhance the effectiveness of traditional forest conservation efforts while benefitting resource-poor farmers.Environmental Economics and Policy,

Evaluating the affective dimension to support the learning process in the discipline of algorithms: a case study

Este artigo apresenta um estudo visando avaliar aspectos afetivos relacionados aos processos de aprendizagem na área de Algoritmos. A dificuldade apresentada pelos estudantes na aprendizagem de conceitos e técnicas de construção de algoritmos pode levar à frustração, um estado afetivo relacionado aos sentimentos de descontentamento e desesperança. Dois experimentos foram realizados como parte desta pesquisa. No primeiro, um grupo de 58 estudantes foi monitorado enquanto utilizava um sistema de aprendizagem de algoritmos. Quando sentiam-se frustrados na resolução dos exercícios propostos, os alunos podiam indicar este estado ao ambiente de aprendizagem por meio de um botão "Estou Frustrado". Após, um sistema de mineração de dados foi empregado para identificar quais os padrões de interação com o sistema poderiam estar relacionados ao estado de frustração. Estes padrões, representados na forma de regras, foram incorporados no sistema e empregados em um último experimento com um grupo de 6 estudantes com dificuldade de aprendizagem na disciplina. Os resultados da pesquisa mostraram que o sistema foi capaz de prover assistência personalizada aos alunos em momentos em que estes apresentavam dificuldades, auxiliando-os a melhorar seu desempenho.This paper presents a study on the evaluation of affective aspects related to learning processes in the area of Algorithms. Students' difficulties in designing solutions for algorithmic problems may lead to frustration, an affective state related to feelings of disappointment and discouragement. Two experiments were carried out as part of this research. In the first one, a group of 58 students was monitored while using a system for learning algorithms. Whenever the students felt frustrated while working on an algorithmic problem, they could indicate it by pressing a button with the label "I'm frustrated". Later on, a data mining tool was used to identify patterns of student-system interaction that could be related to the state of frustration. These patterns, represented in the form of rules, were then incorporated in the system and used in a last experiment with another group of 6 students who had learning difficulties in the course. Results showed that the system has been able to provide personalized assistance to the students at moments when they were showing difficulties, helping them to improve their performance