Diffraction Resistant Scalar Beams Generated by a Parabolic Reflector and a Source of Spherical Waves

In this work, we propose the generation of diffraction resistant beams by using a parabolic reflector and a source of spherical waves positioned at a point slightly displaced from its focus (away from the reflector). In our analysis, considering the reflector dimensions much greater than the wavelength, we describe the main characteristics of the resulting beams, showing their properties of resistance to the diffraction effects. Due to its simplicity, this method may be an interesting alternative for the generation of long range diffraction resistant waves.Comment: 22 pages, 9 figures, Applied Optics, 201

A Simulation-Based Optimization Framework for Urban Transportation Problems

This paper proposes a simulation-based optimization (SO) method that enables the efficient use of complex stochastic urban traffic simulators to address various transportation problems. It presents a metamodel that integrates information from a simulator with an analytical queueing network model. The proposed metamodel combines a general-purpose component (a quadratic polynomial), which provides a detailed local approximation, with a physical component (the analytical queueing network model), which provides tractable analytical and global information. This combination leads to an SO framework that is computationally efficient and suitable for complex problems with very tight computational budgets. We integrate this metamodel within a derivative-free trust region algorithm. We evaluate the performance of this method considering a traffic signal control problem for the Swiss city of Lausanne, different demand scenarios, and tight computational budgets. The method leads to well-performing signal plans. It leads to reduced, as well as more reliable, average travel times

A tractable analytical model for large-scale congested protein synthesis networks

This paper presents an analytical model, based on finite capacity queueing network theory, to evaluate congestion in protein synthesis networks. These networks are modeled as a set of single server bufferless queues in a tandem topology. This model proposes a detailed state space formulation, which provides a fine description of congestion and contributes to a better understanding of how the protein synthesis rate is deteriorated. The model approximates the marginal stationary distributions of each queue. It consists of a system of linear and quadratic equations that can be decoupled. The numerical performance of this method is evaluated for networks with up to 100,000 queues, considering scenarios with various levels of congestion. It is a computationally efficient and scalable method that is suitable to evaluate congestion for large-scale networks. Additionally, this paper generalizes the concept of blocking: blocking events can be triggered by an arbitrary set of queues. This generalization allows for a variety of blocking phenomena to be modeled.Swiss National Science Foundation (Grant 205320-117581

Dynamic network loading: a stochastic differentiable model that derives link state distributions

We present a dynamic network loading model that yields queue length distributions, accounts for spillbacks, and maintains a differentiable mapping from the dynamic demand on the dynamic queue lengths. The model also captures the spatial correlation of all queues adjacent to a node, and derives their joint distribution. The approach builds upon an existing stationary queueing network model that is based on finite capacity queueing theory. The original model is specified in terms of a set of differentiable equations, which in the new model are carried over to a set of equally smooth difference equations. The physical correctness of the new model is experimentally confirmed in several congestion regimes. A comparison with results predicted by the kinematic wave model (KWM) shows that the new model correctly represents the dynamic build-up, spillback, and dissipation of queues. It goes beyond the KWM in that it captures queue lengths and spillbacks probabilistically, which allows for a richer analysis than the deterministic predictions of the KWM. The new model also generates a plausible fundamental diagram, which demonstrates that it captures well the stationary flow/density relationships in both congested and uncongested conditions

La Informalidad del mercado laboral en el sector comercio de Managua 2009-2013

La realización de este trabajo surge de una motivación por encontrar las respuestas a una serie de interrogantes que, obligatoriamente nos planteamos día tras día al caminar por las calles de Managua, donde se observa la creciente tendencia que ha venido presentando la economía informal en el sector comercio desde hace varios años atrás. Este es un tema de muy vieja data el cual no está presente solo en nuestro país, sino también en diferentes ciudades del mundo y en especial en los países latinoamericanos

Análisis de las condiciones de seguridad vial ligadas a temas de infraestructura en las vías rápidas de Bogotá

Trabajo de investigaciónRevisión del paquete “salve vidas” diseñado por la Organización mundial de la salud (OMS), en la infraestructura vial de Bogotá, con el fin de disminuir el nivel de mortalidad debido a la accidentalidad vial, por medio de la comparación de países que han realizado proyectos para mitigar la accidentalidad vial y que hacen uso de las recomendaciones de la OMS, con el estado actual de las zonas con mayor índice de mortalidad vial de Bogotá.INTRODUCCIÓN. 1. ANTECEDENTES Y JUSTIFICACIÓN. 2. PLANTEAMIENTO Y FORMULACIÓN DEL PROBLEMA. 3. MARCO DE REFERENCIA 4. OBJETIVOS 5. ALCANCES Y LIMITACIONES. 6. METODOLOGÍA. 7. ANTECEDENTES INTERNACIONALES 8. ANÁLISIS DE LA SEGURIDAD VIAL DE BOGOTÁ 9. FACTORES A ESTUDIAR DE INFLUENCIA EN LA ACCIDENTABILIDAD VIAL EN BOGOTÁ 10. POSIBLES CAUSAS DE ACCIDENTALIDAD. 11. ESTUDIO DE LAS ZONAS ROJAS DE BOGOTÁ 12. COMPARACIÓN DE BOGOTÁ CON PAÍSES QUE CUMPLEN CON LAS NORMATIVAS DICTADAS POR LA OMS 13. RESUMEN DE LA COMPARACIÓN CON LOS OTROS PAÍSES. 14. CONCLUSIONES 15. RECOMENDACIONES BIBLIOGRAFÍAPregradoIngeniero Civi

Teaching human anatomy based on 3d anatomical models in the Obstetric Career

ABSTRACT The subject of Human Anatomy treats in a theoretical and practical way the morphology of the different systems of a living being, being one of the preclinical subject's base for every career in the health, through which the future professional is used to diagnose and cure various pathologies.Worldwide the teaching of this subjecthas beenthroughthe master class where the teacher is the one who explains on an illustrative plate to a course of about 40 students, Ecuadorian universities that offer health careers are not the exception. At present there are teachers who resort to these traditional practices, which causes the students community to resort to self-education. This is limited to the acquisition of knowledge in the appropriate manner, resulting in disadvantages in the development of the analytical plan. To this end, the objective is to develop a methodology with learning strategies and techniques through the use of virtual environments and learning methods to improve academic performance inthe firstsemesterofthe ObstetricsCareerofthe CentralUniversityofEcuador. In order to achieve this objective, a methodology based on Design Science has been created, which aims to solve social problems through the use and application of technological devices. These devices such as 3D models have been implemented together with the Design Science methodology to positively influence academic performance. (221) In order to achieve this objective,a methodologybased onDesignScience has beencreated,which aims tosolve social problems through the use and application of technological devices. These devices such as 3D models have been implemented together with the Design Science methodology to positively influence academic performance. (221) Inorder to achieve this objective, a methodology based on Design Science has beencreated, which aims to solve social problems through the use and applicationof technological devices. These devices such as 3D models have beenimplemented together with the Design Science methodology to positively influence academic performance. (221) KEYWORDS: Academic performance; Human Anatomy; Virtual classroom; 3D anatomical models

Comunicação corporativa e licença social para operar : o caso ARACRUZ Celulose, Guaíba, RS

O objeto deste trabalho é analisar o processo de obtenção da licença social para operar da Aracruz Celulose, Unidade Guaíba, RS, tendo como referência incidente de invasão de suas instalações por membros do movimento de camponeses e trabalhadores sem-terra. A metodologia incluiu uma pesquisa bibliográfica em torno dos conceitos de desenvolvimento sustentável, comunicação corporativa e licença social. Sob a abordagem de uma pesquisa qualitativa, envolveu a análise de conteúdo de matérias de jornais relacionadas ao incidente de invasão da empresa pelo Movimento da Via Campesina e MST, ocorrido em março de 2006. Inclui o histórico da atuação da empresa no Estado, a fim de identificar o processo de constituição de uma política de comunicação corporativa fundamentada em estratégias de diálogo com a comunidade externa, público interno, autoridades governamentais, mídia, ONGs, entre outros. Analisa como se dá o diálogo entre as empresa e estas partes interessadas, a fim de constituir um roteiro eficaz para obtenção de sua licença social para operar. Conclui que, em função das manifestações solidárias à empresa ocorridas a partir do incidente, revela-se uma tendência favorável à obtenção da licença social para operar entre parcela das partes interessadas da empresa no Estado

ANÁLISIS ESPACIAL DE LA SEGREGACIÓN TERRITORIAL EL CASO DE LA COMUNIDAD LÉSBICO-GAY EN LAS CIUDADES DE TOLUCA Y MÉXICO. CAUSAS Y CONSECUENCIAS SOCIOCULTURALES.

Se determina el análisis espacial sobre la dinámica sociocultural de la comunidad Lésbico, Gay, Bisexual, Transexual, Travesti, Transgénero e Intersexual (LGBTTTI) en las ciudades de México y Toluca para determinar los niveles y formas de segregación territorial. Por tal motivo es necesario delimitar y caracterizar el área de estudio, elaborar el conteo y caracterización de los sitios de reunión (Clubes, Bares, Antros, Café, Restaurantes, Hoteles, Gimnasios, Spa, Estéticas, Transportes, Tours y Marchas). Por medio de cartografía específica (cartas topográficas a escala 1:50 000, del Estado de México), se elaboró la cartografía sobre la distribución espacial de los sitios de reunión y el análisis de segregación territorial, además, se cuantificó la magnitud de la comunidad (LGBTTTI) por sitio de reunión y determinó espacialmente el área de influencia de las comunidades (LGBTTTI) de la Ciudad de Toluca, la cartografía automatizada, permitió matizar mucho mejor, la zona de estudio de acuerdo a las visibilidades gay que existen en las diferentes zonas. El análisis espacial y las formas de segregación están fundamentadas bajo la Geografía Social, se interesa por la expresión de las relaciones de la sociedad y analiza e interpreta sus cambiantes procesos en el mundo bajo una perspectiva espacio temporal. A través de la investigación se examinó la diferencia de los territorios, la identidad de las regiones, las estrategias y medios para su transformación por parte de los habitantes, los procesos de cambio social y las dinámicas demográficas y urbanas. En términos generales, el concepto de segregación refiere a “…la existencia de diferencias o desigualdades dentro de un colectivo y a la separación de los sujetos en categorías que tienen cierto grado de distinción jerárquica o valorativa” (Rodríguez. 2001)