BCN-Routing : càlcul web de rutes amb pgRouting, OpenStreetMaps i OpenLayers

Es presenta un sistema acurat de càlcul web d'itineraris mínims (per a vianants i per a vehicles) entre dos punts de la ciutat de Barcelona, un dels quals es triat per l'usuari directament a sobre un mapa i l'altre, alternativament, a sobre el mateix mapa o bé a sobre una llista de selecció de les principals atraccions turístiques de Barcelona.El sistema es troba implementat per medi de MapServer (1) com a servidor, OpenLayers (2) per a la interfície d'usuari, una base de dades PostrgreSQL (3)/PostGIS (4) que recull dades d'OpenStreetMaps (5) per a la navegació i dades introduïdes manualment, per a la llista de selecció d'atraccions turístiques. Per al càlcul d'itineraris es fa servir, pgRouting (6) alhora que s'accedeix a la cartografia de CartoCiudad (7) per a mostrar un mapa de base i opcionalment els noms dels carrers i punts d'interès a partir de les capes FondoUrbano, Vial i Topónimo del servidor WMS de CartoCiudad.Tot el sistema corre a sobre Windows 7 Home Premium (8).Així mateix es presenten quatre noves funcions i un tipus definit per l'usuari de PostgreSQL per al càlcul acurat d'itineraris mínims i l'estudi teòric que justifica la seva bondat.

Problemas en la implementación de algoritmos de routing de alta complejidad en dispositivos móviles: el caso Itiner@

La aparición de terminales de telefonía móvil cada vez más potentes abre un nuevo abanico de posibilidades en cuanto a usos y aplicaciones. Sin embargo, y dadas las limitaciones tanto de memoria como de CPU que tienen estos dispositivos, algunas de las aplicaciones potenciales resultan muy difíciles o incluso imposibles de llevar a la práctica. Este es el caso, por ejemplo, de aplicaciones de cálculo de rutas. En el contexto del proyecto Itiner@, un asistente para rutas turísticas completamente autónomo que debe funcionar incluso sin conexión a Internet, todos los procesos deben ejecutarse íntegramente de forma local en el dispositivo móvil. Dado que es un proyecto orientado al ocio, es importante que la experiencia del usuario sea satisfactoria, por lo que además de poder ejecutar el algoritmo de cálculo de rutas, el sistema debe hacerlo de forma rápida. En este sentido, los algoritmos recursivos habituales son demasiado costosos o lentos para su uso en Itiner@ y ha sido necesario reinventar este tipo de algoritmos en función de las limitaciones que tienen estos dispositivos. En el presente trabajo se presenta el proceso seguido y las dificultades encontradas para implementar un algoritmo recursivo de cálculo de rutas que se ejecute íntegramente en un dispositivo móvil Android de forma eficiente. Así, finalmente se llega a un algoritmo recursivo de cálculo de rutas para dispositivos móviles que se ejecuta de forma más eficiente frente a algoritmos directamente portados a dispositivos móviles. La principal contribución del trabajo es doble: por un lado ofrece algunas guías útiles al desarrollo de algoritmos más eficientes para dispositivos móviles; y por el otro, muestra un algoritmo de cálculo de rutas que funciona con un tiempo de respuesta aceptable, en un entorno exigente, como es el de las aplicaciones de turismo en móviles

Enhancing fault management performance of two-step QoS routing algorithms in GMPLS networks

In this paper a novel methodology aimed at minimizing the probability of network failure and the failure impact (in terms of QoS degradation) while optimizing the resource consumption is introduced. A detailed study of MPLS recovery techniques and their GMPLS extensions are also presented. In this scenario, some features for reducing the failure impact and offering minimum failure probabilities at the same time are also analyzed. Novel two-step routing algorithms using this methodology are proposed. Results show that these methods offer high protection levels with optimal resource consumption

Enhancing MPLS QoS routing algorithms by using the network protection degree paradigm

IP based networks still do not have the required degree of reliability required by new multimedia services, achieving such reliability will be crucial in the success or failure of the new Internet generation. Most of existing schemes for QoS routing do not take into consideration parameters concerning the quality of the protection, such as packet loss or restoration time. In this paper, we define a new paradigm to develop new protection strategies for building reliable MPLS networks, based on what we have called the network protection degree (NPD). This NPD consists of an a priori evaluation, the failure sensibility degree (FSD), which provides the failure probability and an a posteriori evaluation, the failure impact degree (FID), to determine the impact on the network in case of failure. Having mathematical formulated these components, we point out the most relevant components. Experimental results demonstrate the benefits of the utilization of the NPD, when used to enhance some current QoS routing algorithms to offer a certain degree of protection

Minimum interference routing with fast protection

One of the most effective techniques offering QoS routing is minimum interference routing. However, it is complex in terms of computation time and is not oriented toward improving the network protection level. In order to include better levels of protection, new minimum interference routing algorithms are necessary. Minimizing the failure recovery time is also a complex process involving different failure recovery phases. Some of these phases depend completely on correct routing selection, such as minimizing the failure notification time. The level of protection also involves other aspects, such as the amount of resources used. In this case shared backup techniques should be considered. Therefore, minimum interference techniques should also be modified in order to include sharing resources for protection in their objectives. These aspects are reviewed and analyzed in this article, and a new proposal combining minimum interference with fast protection using shared segment backups is introduced. Results show that our proposed method improves both minimization of the request rejection ratio and the percentage of bandwidth allocated to backup paths in networks with low and medium protection requirements

QoS online routing and MPLS multilevel protection: a survey

A survey of MPLS protection methods and their utilization in combination with online routing methods is presented in this article. Usually, fault management methods pre-establish backup paths to recover traffic after a failure. In addition, MPLS allows the creation of different backup types, and hence MPLS is a suitable method to support traffic-engineered networks. In this article, an introduction of several label switch path backup types and their pros and cons are pointed out. The creation of an LSP involves a routing phase, which should include QoS aspects. In a similar way, to achieve a reliable network the LSP backups must also be routed by a QoS routing method. When LSP creation requests arrive one by one (a dynamic network scenario), online routing methods are applied. The relationship between MPLS fault management and QoS online routing methods is unavoidable, in particular during the creation of LSP backups. Both aspects are discussed in this article. Several ideas on how these actual technologies could be applied together are presented and compared

Adding QoS protection in order to enhance MPLS QoS routing

In this paper, a method for enhancing current QoS routing methods by means of QoS protection is presented. In an MPLS network, the segments (links) to be protected are predefined and an LSP request involves, apart from establishing a working path, creating a specific type of backup path (local, reverse or global). Different QoS parameters, such as network load balancing, resource optimization and minimization of LSP request rejection should be considered. QoS protection is defined as a function of QoS parameters, such as packet loss, restoration time, and resource optimization. A framework to add QoS protection to many of the current QoS routing algorithms is introduced. A backup decision module to select the most suitable protection method is formulated and different case studies are analyzed

All-Optical Label Stacking: Easing the Trade-offs Between Routing and Architecture Cost in All-Optical Packet Switching

All-optical label swapping (AOLS) forms a key technology towards the implementation of all-optical packet switching nodes (AOPS) for the future optical Internet. The capital expenditures of the deployment of AOLS increases with the size of the label spaces (i.e. the number of used labels), since a special optical device is needed for each recognized label on every node. Label space sizes are affected by the way in which demands are routed. For instance, while shortest-path routing leads to the usage of fewer labels but high link utilization, minimum interference routing leads to the opposite. This paper studies all-optical label stacking (AOLStack), which is an extension of the AOLS architecture. AOLStack aims at reducing label spaces while easing the compromise with link utilization. In this paper, an integer lineal program is proposed with the objective of analyzing the softening of the aforementioned trade-off due to AOLStack. Furthermore, a heuristic aiming at finding good solutions in polynomial-time is proposed as well. Simulation results show that AOLStack either a) reduces the label spaces with a low increase in the link utilization or, similarly, b) uses better the residual bandwidth to decrease the number of labels even more

Multicast algorithms evaluation using an adaptative routing in ATM networks

This paper proposes a multicast implementation based on adaptive routing with anticipated calculation. Three different cost measures for a point-to-multipoint connection: bandwidth cost, connection establishment cost and switching cost can be considered. The application of the method based on pre-evaluated routing tables makes possible the reduction of bandwidth cost and connection establishment cost individually

Social perceptions of floods and flood management in a Mediterranean area (Costa Brava, Spain)

Taking as an example three study cases in the Costa Brava area, this paper examines the social perceptionof floods through surveys, interviews and Focus Group sessions. Perception is then related to vulnerability, flood management, and citizen’s preferences regarding alternatives to curb flood losses in the future. The study concludes that flood awareness and the willingness to take actions regarding this hazard are clearly related to the degree of social involvement with the affairs of the local community. Furthermore, participatory settings such as Focus Group sessions appear to enable a better environment for assessing and implementing flood management options that attempt to modify human activities rather than modify natural processes as has been frequently the case in the past

Consumer Advisory Bulletin, Price-Gouging Rule in Effect in Storm- and Flood-damaged Counties, August 2007

The Attorney General’s Consumer Protection Division receives hundreds of calls and consumer complaints every year. Follow these tips to avoid unexpected expense and disappointments. This record is about: Price-Gouging Rule in Effect in Storm- and Flood-damaged Counties

Consumer Advisory Bulletin, "Flood and Storm Warning: Be Wary of Impostors Posing as Utility Workers", June 12, 2008

The Attorney General’s Consumer Protection Division receives hundreds of calls and consumer complaints every year. Follow these tips to avoid unexpected expense and disappointments. This record is about: "Look Before You Lease!"

Inventory-routing model, for a multi-period problem with stochastic and deterministic demand

The need for integration in the supply chain management leads us to considerthe coordination of two logistic planning functions: transportation andinventory. The coordination of these activities can be an extremely importantsource of competitive advantage in the supply chain management. The battle forcost reduction can pass through the equilibrium of transportation versusinventory managing costs. In this work, we study the specific case of aninventory-routing problem for a week planning period with different types ofdemand. A heuristic methodology, based on the Iterated Local Search, isproposed to solve the Multi-Period Inventory Routing Problem with stochasticand deterministic demand.

Nest plasticity of Cornitermes silvestrii (Isoptera, Termitidae, Syntermitinae) in response to flood pulse in the Pantanal, Mato Grosso, Brazil

Nest plasticity of Cornitermes silvestrii (Isoptera, Termitidae, Syntermitinae) in response to flood pulse in the Pantanal, Mato Grosso, Brazil. The Pantanal is one of the largest wetlands in the world. Since many areas in Pantanal are flooded during part of the year, it is expected that plants and animals would have mechanisms for their survival during the flooded period. This study investigated the existence of differences in nest shape and inquilines of Cornitermes silvestrii in areas influenced by the flood pulse. We measured the volume, height, width, and height/width ratio of 32 nests in flooded areas and 27 in dry areas, and performed an one-way-Anova with the quasi-Poisson distribution to determine if there were differences in the nest measurements between the points. To analyze the relationship of nest inquilines to flood pulse and nest shape, we performed a regression with a Poisson distribution with the inquiline richness and flood pulse, and the above measurements. The nests of C. silvestrii in flooded areas were significantly higher than nests in dry areas, and had a larger height/width ratio. Colonies in periodically flooded areas would probably make a larger effort to extend their nests vertically, to maintain at least some portion of the structure out of the water and prevent the entire colony from being submerged. Neither the size of the nest nor the flood pulses influenced the assemblage of 11 species found in nests of C. silvestrii.

Stationarity analysis of historical flood series in France and Spain (14th-20th centuries)

Interdisciplinary frameworks for studying natural hazards and their temporal trends have an important potential in data generation for risk assessment, land use planning, and therefore the sustainable management of resources. This paper focuses on the adjustments required because of the wide variety of scientific fields involved in the reconstruction and characterisation of flood events for the past 1000 years. The aim of this paper is to describe various methodological aspects of the study of flood events in their historical dimension, including the critical evaluation of old documentary and instrumental sources, flood-event classification and hydraulic modelling, and homogeneity and quality control tests. Standardized criteria for flood classification have been defined and applied to the Isère and Drac floods in France, from 1600 to 1950, and to the Ter, the Llobregat and the Segre floods, in Spain, from 1300 to 1980. The analysis on the Drac and Isère data series from 1600 to the present day showed that extraordinary and catastrophic floods were not distributed uniformly in time. However, the largest floods (general catastrophic floods) were homogeneously distributed in time within the period 1600¿1900. No major flood occurred during the 20th century in these rivers. From 1300 to the present day, no homogeneous behaviour was observed for extraordinary floods in the Spanish rivers. The largest floods were uniformly distributed in time within the period 1300-1900, for the Segre and Ter rivers.