1,240 research outputs found
Quantifying and modeling ecosystem services provided by urban greening in cities of the Southern Alps, N Italy
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
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 -PAC algorithm (such an algorithm
identifies the best representation with probability at least , and
the best predictor for a task with probability at least ). We
devise an algorithm OSRL-SC whose sample complexity approaches the lower bound,
and scales at most as , with
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 .Comment: Accepted at the Thirty-Seventh AAAI Conference on Artificial
Intelligence (AAAI23
Tube-Based Zonotopic Data-Driven Predictive Control
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
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
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
The school of thought surrounding the urban ecosystem has increasingly become in vogue among researchers worldwide. Since half of the worldâs 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 humanâecosystem 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 dâAragona (1451-1504): politica e ideologia nella dinastia aragonese di Napoli
Questo studio può essere collocato a metĂ 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 â 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 â, si indagano infatti le modalitĂ 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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