Resource dimensioning aspect of heterogeneous traffic with different service requirements: Integration versus segregation

In this paper, we consider the ATM networks in which the virtual path concept is implemented. The question of how to multiplex two or more diverse traffic classes while providing different quality of service requirements is a very complicated open problem. Two distinct options are available: integration and segregation. In an integration approach all the traffic from different connections are multiplexed onto one VP. This implies that the most restrictive QOS requirements must be applied to all services. Therefore, link utilization will be decreased because unnecessarily stringent QOS is provided to all connections. With the segregation approach the problem can be much simplified if different types of traffic are separated by assigning a VP with dedicated resources (buffers and links). Therefore, resources may not be efficiently utilized because no sharing of bandwidth can take place across the VP. The probability that the bandwidth required by the accepted connections exceeds the capacity of the link is evaluated with the probability of congestion (PC). Since the PC can be expressed as the CLP, we shall simply carry out bandwidth allocation using the PC. We first focus on the influence of some parameters (CLP, bit rate and burstiness) on the capacity required by a VP supporting a single traffic class using the new convolution approach. Numerical results are presented both to compare the required capacity and to observe which conditions under each approach are preferred

Optimal Traffic Grooming in WDM using Lighttours

Recent developments in optical communications have allowed simpler optical devices to improve network resource utilization. As such, we propose adding a lambda-monitoring device to a wavelength-routing switch (WRS) allowing better performance when traffic is routed and groomed. This device may allow a WRS to aggregate traffic over optical routes without incurring in optical-electrical-optical conversion for the existing traffic. In other words, optical routes can be taken partially to route demands creating a sort of "lighttours". In this paper, we compare the number of OEO conversions needed to route a complete given traffic matrix using either lighttours or lightpaths

A new approach to real time traffic sign recognition based on colour information

The automatic interpretation of conventional traffic signs is very complex and time consuming. The paper concerns an automatic warning system for driving assistance. It does not interpret the standard traffic signs on the roadside; the proposal is to incorporate into the existing signs another type of traffic sign whose information will be more easily interpreted by a processor. The type of information to be added is profuse and therefore the most important object is the robustness of the system. The basic proposal of this new philosophy is that the co-pilot system for automatic warning and driving assistance can interpret with greater ease the information contained in the new sign, whilst the human driver only has to interpret the "classic" sign. One of the codings that has been tested with good results and which seems to us easy to implement is that which has a rectangular shape and 4 vertical bars of different colours. The size of these signs is equivalent to the size of the conventional signs (approximately 0.4 m2). The colour information from the sign can be easily interpreted by the proposed processor and the interpretation is much easier and quicker than the information shown by the pictographs of the classic signs

G+: Enhanced Traffic Grooming in WDM Mesh Networks using Lighttours

In this article, a new technique for grooming low-speed traffic demands into high-speed optical routes is proposed. This enhancement allows a transparent wavelength-routing switch (WRS) to aggregate traffic en route over existing optical routes without incurring expensive optical-electrical-optical (OEO) conversions. This implies that: a) an optical route may be considered as having more than one ingress node (all inline) and, b) traffic demands can partially use optical routes to reach their destination. The proposed optical routes are named "lighttours" since the traffic originating from different sources can be forwarded together in a single optical route, i.e., as taking a "tour" over different sources towards the same destination. The possibility of creating lighttours is the consequence of a novel WRS architecture proposed in this article, named "enhanced grooming" (G+). The ability to groom more traffic in the middle of a lighttour is achieved with the support of a simple optical device named lambda-monitor (previously introduced in the RingO project). In this article, we present the new WRS architecture and its advantages. To compare the advantages of lighttours with respect to classical lightpaths, an integer linear programming (ILP) model is proposed for the well-known multilayer problem: traffic grooming, routing and wavelength assignment The ILP model may be used for several objectives. However, this article focuses on two objectives: maximizing the network throughput, and minimizing the number of optical-electro-optical conversions used. Experiments show that G+ can route all the traffic using only half of the total OEO conversions needed by classical grooming. An heuristic is also proposed, aiming at achieving near optimal results in polynomial time

Testing for Hidden Information and Action in Automobile Insurance Market

I test the presence of hidden information and action in the automobile insurance market using a data set from several Colombian insurers. To identify the presence of hidden information I find a common knowledge variable providing information on policyholder s risk type which is related to both experienced risk and insurance demand and that was excluded from the pricing mechanism. Such unused variable is the record of policyholder s traffic offenses. I find evidence of adverse selection in six of the nine insurance companies for which the test is performed. From the point of view of hidden action I develop a dynamic model of effort in accident prevention given an insurance contract with bonus experience rating scheme and I show that individual accident probability decreases with previous accidents. This result brings a testable implication for the empirical identification of hidden action and based on that result I estimate an econometric model of the time spans between the purchase of the insurance and the first claim, between the first claim and the second one, and so on. I find strong evidence on the existence of unobserved heterogeneity that deceives the testable implication. Once the unobserved heterogeneity is controlled, I find conclusive statistical grounds supporting the presence of moral hazard in the Colombian insurance market.

Tráfico del demonio: vías y vidas de las motocicletas en Bogotá

En las últimas dos décadas el crecimiento de la ciudad ha generado una serie de problemas relacionados con la movilidad y el transporte para los bogotanos. La incapacidad de los distintos gobiernos distritales al proponer soluciones efectivas para mejorar dichas problemáticas, ha provocado que los ciudadanos busquen distintas alternativas para mejorar su movilización. El mercado y la ciudadanía encontraron en las motos una respuesta a los problemas del transporte en la ciudad, sin embargo, esta alternativa viene acompañada de una serie de efectos que por sí mismas repercuten y ahondan el problema de movilidad. Este trabajo pretende determinar las causas y consecuencias del uso de la moto en Bogotá como alternativa de movilización, ello a través de la mirada tanto de conductores de motocicletas como de los demás participantes de las vías y calles de la ciudad.

Accidents infantils de 0 a 6 anys : Programa d'Educació Sanitària. 'Accidentes infantiles de 0 a 6 años : Programa de Educación Sanitaria'.

Resumen del autor en catalán

Accidents infantils de 7 a 14 anys : Programa d'Educació Sanitària. 'Accidentes infantiles de 7 a 14 años : Programa de Educación Sanitaria'.

Resumen del autor en catalán

Accidents de treball : curar-se en salut. Primers Auxilis III. 'Accidentes de trabajo : curarse en salud. Primeros Auxilios III'.

Vídeo destinado a la prevención de los accidentes laborales: quemadas químicas producidas por productos varios. Explica las normas de primeros auxilios según el producto interior de la quemada. Presenta las normas de actuación ante objetos cítricos en el ojo. Se dedica una parte del vídeo para hacer ver la importancia de la revisión y atención médicas en el ámbito laboral.

Els accidents de 7 a 14 anys. 'Los accidentes de 7 a 14 a??os'

Se presentan varias situaciones de riesgo con ni??os de siete a catorce a??os: cruzar la calle, subir a un ??rbol, juegos deportivos, laboratorio, animales de compa????a, playa, bicicleta, etc. Se comenta y analiza la manera de evitar los accidentes.

Accidents de muntanya : curar-se en salut. Primers Auxilis II. 'Accidentes de montaña : curarse en salud. Primeros Auxilios II'.

Duración 29 minutos

Accidents de trànsit : curar-se en salut. Primers Auxilis I. 'Accidentes de tráfico : curarse en salud. Primeros Auxilios I'.

Video destinado a la prevención de los accidentes de tráfico:las fracturas de las extremidades, las precauciones que se deben tomar para evitar incendios, la posición de defensa,etc. Se trabajan las consecuencias sobre imprudencias con distintos tipos de transportes motorizados.

Avoiding accidents. 'Evitar los accidentes'.

Se presenta una secuencia didáctica sobre normas básicas de Educación Vial contextualizadas en situaciones cotidianas donde el niño es sujeto activo. Se plantea un juego de mesa sencillo como hilo conductor de las actividades que inciden en el refuerzo de actitudes seguras.

Traffic.

A través de la película de Steven Soderbergh se ofrecen propuestas educativas de experiencia, reflexión y acción común para ser realizadas en el aula. Además de la ficha técnica y el argumento, se presenta un conjunto de actividades relacionadas con la película. Se ofrecen una serie de cuestiones o preguntas en las cuales se indaga sobre aspectos relacionados con la droga, el blanqueo de dinero y los paraisos fiscales.

Bumper to Bumper : a traffic jam.

Básicamente se trata de la historia de un embotellamiento. Muestra más de treinta vehículos diferentes y de sus conductores y pasajeros atrapados en un gigantesco atasco. Al final se ve la causa de la congestión. Los modos de transporte se identifican claramente a través del texto en negrita. El libro muestra señales del mundo moderno a través de imágenes, como un hombre hablando por su teléfono móvil. Los niños pueden descubrir y comentar la gran variedad de emociones mostradas por la gente a través de la expresiones faciales, los movimientos, y las actividades.