1,240 research outputs found

    Quantifying and modeling ecosystem services provided by urban greening in cities of the Southern Alps, N Italy

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    Population growth in urban areas is a world-wide phenomenon. According to a recent United Nations report, over half of the world now lives in cities. Numerous health and environmental issues arise from this unprecedented urbanization. Recent studies have demonstrated the effectiveness of urban green spaces and the role they play in improving both the aesthetics and the quality of life of its residents. In particular, urban green spaces provide ecosystem services such as: urban air quality improvement by removing pollutants that can cause serious health problems, carbon storage, carbon sequestration and climate regulation through shading and evapotranspiration. Furthermore, epidemiological studies with controlled age, sex, marital and socio-economic status, have provided evidence of a positive relationship between green space and the life expectancy of senior citizens. However, there is little information on the role of public green spaces in mid-sized cities in northern Italy. To address this need, a study was conducted to assess the ecosystem services of urban green spaces in the city of Bolzano, South Tyrol, Italy. In particular, we quantified the cooling effect of urban trees and the hourly amount of pollution removed by the urban forest. The information was gathered using field data collected through local hourly air pollution readings, tree inventory and simulation models. During the study we quantified pollution removal for ozone, nitrogen dioxide, carbon monoxide and particulate matter (<10 microns). We estimated the above ground carbon stored and annually sequestered by the urban forest. Results have been compared to transportation CO2 emissions to determine the CO2 offset potential of urban streetscapes. Furthermore, we assessed commonly used methods for estimating carbon stored and sequestered by urban trees in the city of Bolzano. We also quantified ecosystem disservices such as hourly urban forest volatile organic compound emissions

    On the Sample Complexity of Representation Learning in Multi-task Bandits with Global and Local structure

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    We investigate the sample complexity of learning the optimal arm for multi-task bandit problems. Arms consist of two components: one that is shared across tasks (that we call representation) and one that is task-specific (that we call predictor). The objective is to learn the optimal (representation, predictor)-pair for each task, under the assumption that the optimal representation is common to all tasks. Within this framework, efficient learning algorithms should transfer knowledge across tasks. We consider the best-arm identification problem for a fixed confidence, where, in each round, the learner actively selects both a task, and an arm, and observes the corresponding reward. We derive instance-specific sample complexity lower bounds satisfied by any (δG,δH)(\delta_G,\delta_H)-PAC algorithm (such an algorithm identifies the best representation with probability at least 1−δG1-\delta_G, and the best predictor for a task with probability at least 1−δH1-\delta_H). We devise an algorithm OSRL-SC whose sample complexity approaches the lower bound, and scales at most as H(Glog⁡(1/δG)+Xlog⁡(1/δH))H(G\log(1/\delta_G)+ X\log(1/\delta_H)), with X,G,HX,G,H being, respectively, the number of tasks, representations and predictors. By comparison, this scaling is significantly better than the classical best-arm identification algorithm that scales as HGXlog⁡(1/δ)HGX\log(1/\delta).Comment: Accepted at the Thirty-Seventh AAAI Conference on Artificial Intelligence (AAAI23

    Tube-Based Zonotopic Data-Driven Predictive Control

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    We present a novel tube-based data-driven predictive control method for linear systems affected by a bounded addictive disturbance. Our method leverages recent results in the reachability analysis of unknown linear systems to formulate and solve a robust tube-based predictive control problem. More precisely, our approach consists in deriving, from the collected data, a zonotope that includes the true error set. In addition to that, we show how to guarantee the stability of the resulting error zonotope in a probabilistic sense. Results on a double-integrator affected by strong adversarial noise demonstrate the effectiveness of the proposed control approach

    Data-Driven Control and Data-Poisoning attacks in Buildings: the KTH Live-In Lab case study

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    This work investigates the feasibility of using input-output data-driven control techniques for building control and their susceptibility to data-poisoning techniques. The analysis is performed on a digital replica of the KTH Livein Lab, a non-linear validated model representing one of the KTH Live-in Lab building testbeds. This work is motivated by recent trends showing a surge of interest in using data-based techniques to control cyber-physical systems. We also analyze the susceptibility of these controllers to data-poisoning methods, a particular type of machine learning threat geared towards finding imperceptible attacks that can undermine the performance of the system under consideration. We consider the Virtual Reference Feedback Tuning (VRFT), a popular data-driven control technique, and show its performance on the KTH Live-In Lab digital replica. We then demonstrate how poisoning attacks can be crafted and illustrate the impact of such attacks. Numerical experiments reveal the feasibility of using data-driven control methods for finding efficient control laws. However, a subtle change in the datasets can significantly deteriorate the performance of VRFT

    Conformal Off-Policy Evaluation in Markov Decision Processes

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    Reinforcement Learning aims at identifying and evaluating efficient control policies from data. In many real-world applications, the learner is not allowed to experiment and cannot gather data in an online manner (this is the case when experimenting is expensive, risky or unethical). For such applications, the reward of a given policy (the target policy) must be estimated using historical data gathered under a different policy (the behavior policy). Most methods for this learning task, referred to as Off-Policy Evaluation (OPE), do not come with accuracy and certainty guarantees. We present a novel OPE method based on Conformal Prediction that outputs an interval containing the true reward of the target policy with a prescribed level of certainty. The main challenge in OPE stems from the distribution shift due to the discrepancies between the target and the behavior policies. We propose and empirically evaluate different ways to deal with this shift. Some of these methods yield conformalized intervals with reduced length compared to existing approaches, while maintaining the same certainty level

    Urban Ecosystem Services: Toward a Sustainable Future

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    The school of thought surrounding the urban ecosystem has increasingly become in vogue among researchers worldwide. Since half of the world’s population lives in cities, urban ecosystem services have become essential to human health and well-being. Rapid urban growth has forced sustainable urban developers to rethink important steps by updating and, to some degree, recreating the human–ecosystem service linkage. This talk addresses topics such as ecosystem services, green infrastructure, nature-based solutions, urban green spaces, edible green infrastructure, human health, and more. It highlights current knowledge, gaps, and future research with the focus on building a sustainable future

    Federico d’Aragona (1451-1504): politica e ideologia nella dinastia aragonese di Napoli

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    Questo studio può essere collocato a metà strada tra una biografia principesca in senso stretto, e la parziale ricostruzione del profilo politico-ideologico non solo del singolo personaggio storico, ma di una dinastia regnante del XV secolo. Utilizzando come punto d'osservazione le vicende del figlio secondogenito di Ferrante I d'Aragona, Federico – che fu sovrano del Regno di Napoli dal 1496 al 1501, e ancor prima principe inserito a fondo nelle istituzioni regnicole e nei disegni politici dei precedenti monarchi –, si indagano infatti le modalità della costruzione e rappresentazione del potere, i sistemi di governo e le strutture ideologiche degli Aragonesi del ramo napoletano, interrogandosi anche sulle cause della loro caduta. Il largo uso delle fonti diplomatiche, integrato con gli apporti di fonti giuridiche, letterarie, cronachistiche e storiografiche, permette inoltre di inserire le dinamiche aragonesi nel contesto serrato della politica del Quattrocento, non solo italiana, ma europea
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