AUV/ASC cooperative survey

In this paper we describe a solution to perform autonomous surveys taking advantage of a cooperative multivehicle setup. In the proposed configuration, an ASC provides –through an USBL- absolute positioning and communications to an AUV. Thus, by following the AUV with the surface vehicle we facilitate the reception of USBL measurements in the AUV regardless of the extent of the mission. This turns into an improved navigation on the AUV’s side, with the drift bounded thanks to the absolute measurements. Experimental results show that the proposed algorithm is able to maintain the ASC at a close distance and improve the navigation of the AUV. Moreover, the bathymetric maps built from the AUV data are consistent enough to enable the automatic detection of present targets and program further localized missions in the area.Peer Reviewe

Active SLAM for autonomous underwater exploration

Exploration of a complex underwater environment without an a priori map is beyond the state of the art for autonomous underwater vehicles (AUVs). Despite several efforts regarding simultaneous localization and mapping (SLAM) and view planning, there is no exploration framework, tailored to underwater vehicles, that faces exploration combining mapping, active localization, and view planning in a unified way. We propose an exploration framework, based on an active SLAM strategy, that combines three main elements: a view planner, an iterative closest point algorithm (ICP)-based pose-graph SLAM algorithm, and an action selection mechanism that makes use of the joint map and state entropy reduction. To demonstrate the benefits of the active SLAM strategy, several tests were conducted with the Girona 500 AUV, both in simulation and in the real world. The article shows how the proposed framework makes it possible to plan exploratory trajectories that keep the vehicle’s uncertainty bounded; thus, creating more consistent maps.Peer ReviewedPostprint (published version

Geographical deviations in foreign trade statistics: A study into European trade with Latin American Countries, 1925

We have analyzed the spatial accuracy of European foreign trade statistics compared to Latin American. We have also included USA’s data because of the importance of this country in Latin American trade. We have developed a method for mapping discrepancies between exporters and importers, trying to isolate systematic spatial deviations. Although our results don’t allow a unique explanation, they present some interesting clues to the distribution channels in the Latin American Continent as well as some spatial deviations for statistics in individual countries. Connecting our results with the literature specialized in the accuracy of foreign trade statistics; we can revisit Morgernstern (1963) as well as Federico and Tena (1991). Morgernstern had had a really pessimistic view on the reliability of this statistic source, but his main alert was focused on the trade balances, not in gross export or import values. Federico and Tena (1991) have demonstrated how accuracy increases by aggregation, geographical and of product at the same time. But they still have a pessimistic view with relation to distribution questions, remarking that perhaps it will be more accurate to use import sources in this latest case. We have stated that the data set coming from foreign trade statistics for a sample in 1925, being it exporters or importers, it’s a valuable tool for geography of trade patterns, although in some specific cases it needs some spatial adjustments.Economic geography, statistical accuracy, foreign trade statistics

Adaptació de les instal·lacions d'un local de festes d'ús privat per a la obertura al públic

Es presenta a continuació el Projecte Final de Carrera a l’Escola d’Enginyeria Tècnica Industrial de Barcelona (EUETIB) de Marc Gonzalez Carreras, estudiant d’Enginyeria Tècnica Industrial en l’especialitat de Mecànica. El que s’ha realitzat en aquest projecte és l’adequació d’una sala de festes d’ús privat a Tiana, i la adaptació de les instal·lacions a la normativa vigent per poder-la obrir al públic i obtenir la llicència d’activitat. Les instal·lacions que s’han tractat són: reformes constructives, electricitat, il·luminació, ventilació, climatització, protecció contra incendis, i sonorització. A partir de les normatives europees, nacionals, autonòmiques i municipals, s’han anat dissenyant les diverses instal·lacions i fet els plànols corresponents que s’han cregut convenients, així com la informació addicional utilitzada per a realitzar el projecte en els annexos

Diseño de un sistema de baliza automática para puertos deportivos

Este proyecto se centra en el diseño conceptual de una baliza automática para uso en puertos deportivos. A partir del estado del arte se ha constatado que el mercado actual es inexistente, así pues, partiendo de cero, se han creado dos posibles conceptos. Estos conceptos incluyen un diseño del sistema mecánico, electrónico y de telecomunicaciones. Dicha embarcación de servicios tendrá la función de baliza, la cual estará dentro de puerto y se encargará de ir a buscar embarcaciones y guiarlas hasta su amarre. Todo esto de forma automática. Con tal de realizar un diseño conceptual, primero se estudiará las opciones que presenta el mercado, para posteriormente presentar dos alternativas que puedan cumplir las funciones deseadas. Con la ayuda del programa de diseño asistido Solidworks 2018 se presentan las soluciones conceptuales de ambas propuestas. Para el análisis de la embarcación, a partir del planteamiento de las ecuaciones matemáticas y físicas se realiza una simulación de su funcionamiento. Esta simulación va acompañada de una hoja de cálculo que simula el controlador PID incorporado. Todo esto con el fin de tomar la decisión de cuál de las dos propuestas es la más adecuada para este proyecto y su fin

La fiabilidad de la asignación geográfica en las estadísticas de comercio exterior: América Latina y el Caribe

The statistical accuracy of Historical Foreign Trade Sources has been stated by Federico and Tena (1991) and Tena (1985, 19991 y 1992). This article follows his works in the most suspect field: geographical distribution. We have use Latin American Coal Trade Data among 1908-1930. Most international trade, considering weight, was coal trade; meanwhile it is an ideal product to isolate geographical effects. Statistical disagreements persistence makes us to think this is not a random phenomenon. We have specified an econometric model based on distance. Results show that including geography we can understand statistical disagreements. As a consequence Latin American Sources appear reasonably accurate, considering its geographical pattern.La fiabilidad de las estadísticas de comercio exterior a nivel agregado fue analizada detalladamente por Federico y Tena (1991) y Tena (1985, 19991 y 1992). Este artículo sigue el trabajo de estos autores, adentrándose en el ámbito más problemático de la distribución geográfica. Para ello se han usado los datos del comercio de carbón de América Latina y el Caribe entre 1908 y 1930. Por un lado, el carbón resulta un buen representante del comercio internacional, en términos de peso, y por otro lado, precisamente por su peso, se trata de un producto que permite aislar los posibles efectos geográficos en el registro estadístico. La persistencia temporal, tanto del signo como de la magnitud, de las discrepancias estadísticas entre socios comerciales lleva a plantear un modelo econométrico que introduce la distancia como explicación de tales diferencias. Los resultados de la estimación ponen de manifiesto la aceptable calidad de las estadísticas latinoamericanas, en volúmenes, una vez considerados los patrones geográficos de la distribución comercial.Publicad

The First World War and Coal Trade Geography in Latin America and the Caribbean, 1890-1930

This paper aims to illustrate the dynamics of coal trade between Latin America and its main trade partners, i.e., the USA, Great Britain, and Germany, before and after the enormous disruption caused by the First World War. The coal trade was used as an indicator of modernization for Latin American countries, given that oil was at that time of secondary importance. Energy imports have determined the possibilities of each Latin American country in its process of development. Here, we address this question and place special emphasis on supply channels, concluding that the trade link with main suppliers was of key significance. Although this was very clear by the end of the period, the process had started well before the First World War, at least for the majority of LA&C countries. These points are developed through a gravity model applied to the bilateral coal trade. The importance of the market supplier share is addressed through cluster methodologies

Fiabilidad de las estadísticas de comercio exterior referentes a América Latina y el Caribe (1908-1930) - Una aproximación al patron geográfico de las discrepancias distributivas a traves del carbón

The statistical accuracy of Historical Foreign Trade Sources has been stated by Federico and Tena (1991) and Tena (1985, 19991 y 1992). This article follows his works in the most suspect field: geographical distribution. We have use Latin American Coal Trade Data among 1908-1930. Most international trade, considering weight, was coal trade; meanwhile it is an ideal product to isolate geographical effects. Statistical disagreements persistence makes us to think this is not a random phenomenon. We have specified an econometric model based on distance. Results show that including geography we can understand statistical disagreements. As a consequence Latin American Sources appear reasonably accurate, as well as those of its trade partners, considering each geographical pattern. The knowledge of the statistical sources error allows us to learn about their reliability margins.Fiabilidad Estadistica, Comercio Exterior, America Latina y el Caribe, Comercio de carbon, Geografia economica