Developing personas to improve understanding of users’ needs in digital mobility: An experience of the DIGNITY project in the Barcelona Metropolitan Area
Al andar se hace camino y al volver la vista atrás se ve la senda que nunca se ha de volver a pis... more Al andar se hace camino y al volver la vista atrás se ve la senda que nunca se ha de volver a pisar. Caminante, no hay camino, sino estelas en la mar. Caminante, son tus huellas el camino, y nada más; caminante, no hay camino, se hace camino al andar.
Sea-land interaction along the Catalan coast (NW Mediterranean): Assessment of Submarine Groundwater Discharge (SGD) based on seawater nutrient concentrations
Measurements in sequencing studies are mostly based on counts. There is a lack of theoretical dev... more Measurements in sequencing studies are mostly based on counts. There is a lack of theoretical developments for the analysis and modelling of this type of data. Some thoughts in this direction are presented, which might serve as a seed. The main issues addressed are the compositional character of multinomial probabilities and the corresponding representation in orthogonal (isometric) coordinates, and modelling distributions for sequencing data taking into account possible effects of amplification techniques.
Characterizing the evolution of the Yangtze River Delta multi-port system using compositional data techniques
Maritime Policy & Management, 2021
The Yangtze River Delta multi-port system (YMPS) receives increasing attention due to its relevan... more The Yangtze River Delta multi-port system (YMPS) receives increasing attention due to its relevance in world trade and excellent competitiveness in the container traffic market. To insight into the...
The aim of this work is to present and test a novel approach to describe access to community drin... more The aim of this work is to present and test a novel approach to describe access to community drinking water points for planning purposes. The technical limits and possible benefits of including compositional population description based on service level into water and sanitation sector-related planning is illustrated with a simplified case example. New conceptual frameworks, such as the human right to water and sanitation and the Sustainable Development Goals, consider in addition to physical access to the infrastructure the explicit inclusion of availability, affordability, acceptability and quality criteria. These approaches also point the identification of vulnerable groups with respect to the provision of a minimum level of service (1).Typically, regional planners compare the situation between local administrations through the average value of service-based indicators at the household level (2). However, the suitability of this planning approach may be questioned as it will hard...
Monitoring energy indicators has acquired a renewed interest with the 2030 Agenda for Sustainable... more Monitoring energy indicators has acquired a renewed interest with the 2030 Agenda for Sustainable Development, and specifically with goal 7 (SDG7), which seeks to guarantee universal access to energy. The predominant criteria to monitor SDG7 are given in a set of individual indicators. Along this line, the UN indicators proposed in the 47th session of the UN Statistical commission are a practical starting point. A relevant characteristic of these indicators is that they can be expressed as proportions from a whole, i.e., they are compositions. Notably, directly implementing traditional multivariate models onto indicators that are proportions without an intermediate process can lead to spurious analysis. Here, we aim to assess the application of compositional data analysis(CoDa) to follow up on the temporal trend indicators of the energy sector in the context of SDG7, with a case study for the most affected areas addressing the problem of electricity access. Following CoDa methodology, we first use a log-ratio transformation to bring compositions to real space and then apply three multivariate methods: linear regression, generalized additive models and support vector machine. We also address other characteristic problems of the electricity access indicators, such as data quality, which was treated by considering mod
Extreme events, such as wave-storms, need to be characterized for coastal infrastructure design p... more Extreme events, such as wave-storms, need to be characterized for coastal infrastructure design purposes. Such description should contain information on both the univariate behaviour and the joint-dependence of storm-variables. These two aspects have been here addressed through generalized Pareto distributions and hierarchical Archimedean copulas. A non-stationary model has been used to highlight the relationship between these extreme events and non-stationary climate. It has been applied to a Representative Concentration pathway 8.5 Climate-Change scenario, for a fetch-limited environment (Catalan Coast). In the non-stationary model, all considered variables decrease in time, except for storm-duration at the northern part of the Catalan Coast. The joint distribution of storm variables presents cyclical uctuations, with a stronger inuence of climate dynamics than of climate itself.
Storm surges are one of the main drivers for extreme flooding at the coastal areas. Such events c... more Storm surges are one of the main drivers for extreme flooding at the coastal areas. Such events can be characterized with the maximum level in an extreme storm surge event (surge peak), as well as the duration of the event. Surge projections come from a barotropic model for the 1950–2100 period, under a severe climate change scenario (RCP 8.5) at the northeastern Spanish coast. The relationship of extreme storm surges to three large-scale climate patterns was assessed: North Atlantic Oscillation ( N A O ), East Atlantic Pattern ( E A W R ), and Scandinavian Pattern ( S C ). The statistical model was built using two different strategies. In Strategy #1, the joint probability density was characterized by a moving-average series of stationary Archimedean copula, whereas in Strategy #2, the joint probability density was characterized by a non-stationary probit copula. The parameters of the marginal distribution and the copula were defined with generalized additive models. The analysis s...
Abstract:- The European institutions of higher education have undertaken one of the most importan... more Abstract:- The European institutions of higher education have undertaken one of the most important educational reform movements in history. It represents an opportunity for renovation and improvement which will require profound reflection, perseverance and a common effort on the part of all those involved in higher education. The concepts and strategies defined in the Bologna Process to develop a European Higher Education Area (EHEA), involve a change in the educative programs. This change has to be adapted to innovative teaching and learning processes based on achieving specific knowledge according to the degree, and based on developing abilities and skills to adapt that knowledge to the professional field of work. Thus, the method has to be focused in the learning process (based in the student and his capability to learn) and not in the teaching process (based in the teacher work). In this paper, we will describe several experiences applied at the Technical University of Catalonia...
The European institutions of higher education have undertaken one of the most important education... more The European institutions of higher education have undertaken one of the most important educational reform movements in history. It represents an opportunity for renovation and improvement which will require profound reflection, perseverance and a common effort on the part of all those involved in higher education. The concepts and strategies defined in the Bologna Process to develop a European Higher Education Area (EHEA), involve a change in the educative programs. This change has to be adapted to innovative teaching and learning processes based on achieving specific knowledge according to the degree, and based on developing abilities and skills to adapt that knowledge to the professional field of work. Thus, the method has to be focused in the learning process (based in the student and his capability to learn) and not in the teaching process (based in the teacher work). In this paper, we will describe several experiences applied at the Universitat Politècnica de Catalunya (UPC). ...
Coastal flood risk assessment requires a reliable estimation of the frequency of inundation hazar... more Coastal flood risk assessment requires a reliable estimation of the frequency of inundation hazards, that is, characterising the hazard magnitude and assigning a probability of occurrence. In this work we analyse the uncertainty introduced in the assessment associated to the method to assign the probability of occurrence to coastal flood hazards. To this end we have compared the use of two general methods, the response and the event approaches. Different procedures are used to characterise coastal inundation hazards depending on the analysis scale and data availability. Thus, a range of possibilities has been analysed, from simple estimators such as run-up to modelled flood-prone areas. The analysis has been performed for all wave and water level conditions around the Spanish coast. The results show that the differences between the methods are location-dependent, and thus, determined by the exposure to wave and water level conditions. When using the event approach, the run-up or total water level (with good correlation between waves and surge) distributions reasonably approximate those of the response approach with low associated uncertainty. When the assessment aims to output overtopping discharges or inundation maps, observed differences suggest that the event approach would produce misleading conclusions in inundation-related coastal management and decision-making.
Daily precipitation is recorded as the total amount of water collected by a rain-gauge in 24 h. E... more Daily precipitation is recorded as the total amount of water collected by a rain-gauge in 24 h. Events are modelled as a Poisson process and the 24 h precipitation by a Generalised Pareto Distribution (GPD) of excesses. Hazard assessment is complete when estimates of the Poisson rate and the distribution parameters, together with a measure of their uncertainty, are obtained. The shape parameter of the GPD determines the support of the variable: Weibull domain of attraction (DA) corresponds to finite support variables as should be for natural phenomena. However, Fréchet DA has been reported for daily precipitation, which implies an infinite support and a heavy-tailed distribution. Bayesian techniques are used to estimate the parameters. The approach is illustrated with precipitation data from the Eastern coast of the Iberian Peninsula affected by severe convective precipitation. The estimated GPD is mainly in the Fréchet DA, something incompatible with the common sense assumption of that precipitation is a bounded phenomenon. The bounded character of precipitation is then taken as a priori hypothesis. Consistency of this hypothesis with the data is checked in two cases: using the raw-data (in mm) and using logtransformed data. As expected, a Bayesian model checking clearly rejects the model in the raw-data case. However, logtransformed data seem to be consistent with the model. This fact may be due to the adequacy of the log-scale to represent positive measurements for which differences are better relative than absolute.
A Point-Over-Threshold approach using a reparameterization of the Generalized Pareto Distribution... more A Point-Over-Threshold approach using a reparameterization of the Generalized Pareto Distribution (GPD) has been used to assess changes in the daily rainfall Barcelona series (1854-2006). A Bayesian approach, considering the suitable scale and physical features of the phenomenon, has been used to look for these alterations. Two different models have been assessed: existence of abrupt changes in the new GPD parameters due to modifications of the observatory locations and trends in these GPD parameters, pointing to a climate change scenario.
The reviewer acknowledges the interest of the topic discussed in the manuscript but suggest a lon... more The reviewer acknowledges the interest of the topic discussed in the manuscript but suggest a long list of topics that require further attention or detailed explanation. In general, we agree that the suggested topics are of interest although most of them may be out of the possibilities of the present paper, both due to the limited extension and the fact that these suggested studies require further experience on the use of Bayesian methods to estimate extremal parameters. Precisely, this paper is the result of a second step using this kind of model (two series, secular trend, using extremal data and Generalised Pareto Distribution). The first step was an analysis of ocean waves
Wave-height hazard analysis in Eastern Coast of Spain – Bayesian approach using generalized Pareto distribution
Abstract. Standard practice of wave-height hazard analysis often pays little attention to the unc... more Abstract. Standard practice of wave-height hazard analysis often pays little attention to the uncertainty of assessed return periods and occurrence probabilities. This fact favors the opinion that, when large events happen, the hazard assessment should change accordingly. However, uncertainty of the hazard estimates is normally able to hide the effect of those large events. This is illustrated using data from the Mediterranean coast of Spain, where the last years have been extremely disastrous. Thus, it is possible to compare the hazard assessment based on data previous to those years with the analysis including them. With our approach, no significant change is detected when the statistical uncertainty is taken into account. The hazard analysis is carried out with a standard model. Time-occurrence of events is assumed Poisson distributed. The wave-height of each event is modelled
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Papers by M.I. Ortego