42 research outputs found
An Unsupervised Method for Estimating the Global Horizontal Irradiance from Photovoltaic Power Measurements
In this paper, we present a method to determine the global horizontal
irradiance (GHI) from the power measurements of one or more PV systems, located
in the same neighborhood. The method is completely unsupervised and is based on
a physical model of a PV plant. The precise assessment of solar irradiance is
pivotal for the forecast of the electric power generated by photovoltaic (PV)
plants. However, on-ground measurements are expensive and are generally not
performed for small and medium-sized PV plants. Satellite-based services
represent a valid alternative to on site measurements, but their space-time
resolution is limited. Results from two case studies located in Switzerland are
presented. The performance of the proposed method at assessing GHI is compared
with that of free and commercial satellite services. Our results show that the
presented method is generally better than satellite-based services, especially
at high temporal resolutions
Vehicle-to-grid for car sharing -- A simulation study for 2030
The proliferation of car sharing services in recent years presents a
promising avenue for advancing sustainable transportation. Beyond merely
reducing car ownership rates, these systems can play a pivotal role in
bolstering grid stability through the provision of ancillary services via
vehicle-to-grid (V2G) technologies - a facet that has received limited
attention in previous research. In this study, we analyze the potential of V2G
in car sharing by designing future scenarios for a national-scale service in
Switzerland. We propose an agent-based simulation pipeline that considers
population changes as well as different business strategies of the car sharing
service, and we demonstrate its successful application for simulating scenarios
for 2030. To imitate car sharing user behavior, we develop a data-driven mode
choice model. Our analysis reveals important differences in the examined
scenarios, such as higher vehicle utilization rates for a reduced fleet size as
well as in a scenario featuring new car sharing stations. These disparities
translate into variations in the power flexibility of the fleet available for
ancillary services, ranging from 12 to 50 MW, depending on the scenario and the
time of the day. Furthermore, we conduct a case study involving a subset of the
car sharing fleet, incorporating real-world electricity pricing data. The case
study substantiates the existence of a sweet spot involving monetary gains for
both power grid operators and fleet owners. Our findings provide guidelines to
decision makers and underscore the pressing need for regulatory enhancements
concerning power trading within the realm of car sharing
Maturation signatures of conventional dendritic cell subtypes in COVID‐19 suggest direct viral sensing
Growing evidence suggests that conventional dendritic cells (cDCs) undergo
aberrant maturation in COVID-19, which negatively affects T-cell activation. The presence of
effector T cells in patients with mild disease and dysfunctional T cells in severely ill patients
suggests that adequate T-cell responses limit disease severity. Understanding how cDCs cope
with SARS-CoV-2 can help elucidate how protective immune responses are generated. Here, we
report that cDC2 subtypes exhibit similar infection-induced gene signatures, with the
upregulation of interferon-stimulated genes and interleukin (IL)-6 signaling pathways.
Furthermore, comparison of cDCs between patients with severe and mild disease showed
severely ill patients to exhibit profound downregulation of genes encoding molecules involved
in antigen presentation, such as MHCII, TAP, and costimulatory proteins, whereas we observed
the opposite for proinflammatory molecules, such as complement and coagulation factors. Thus,
as disease severity increases, cDC2s exhibit enhanced inflammatory properties and lose antigen
presentation capacity. Moreover, DC3s showed upregulation of anti-apoptotic genes and
accumulated during infection. Direct exposure of cDC2s to the virus in vitro recapitulated the
activation profile observed in vivo. Our findings suggest that SARS-CoV-2 interacts directly with cDC2s and implements an efficient immune escape mechanism that correlates with disease severity by downregulating crucial molecules required for T-cell activation
Constrained hierarchical networked optimization for energy markets
In this paper, we propose a distributed control strategy for the design of an energy market. The method relies on a hierarchical structure of aggregators for the coordination of prosumers (agents which can produce and consume energy). The hierarchy reflects the voltage level separations of the electrical grid and allows aggregating prosumers in pools, while taking into account the grid operational constraints. To reach optimal coordination, the prosumers communicate their forecasted power profile to the upper level of the hierarchy. Each time the information crosses upwards a level of the hierarchy, it is first aggregated, both to strongly reduce the data flow and to preserve the privacy. In the first part of the paper, the decomposition algorithm, which is based on the alternating direction method of multipliers (ADMM), is presented. In the second part, we explore how the proposed algorithm scales with increasing number of prosumers and hierarchical levels, through extensive simulations based on randomly generated scenarios
A rational decentralized generalized Nash equilibrium seeking for energy markets
We propose a method to design a decentralized energy market which guarantees individual rationality (IR) in expectation, in the presence of system-level grid constraints. We formulate the market as a welfare maximization problem subject to IR constraints, and we make use of Lagrangian duality to model the problem as a n-person non-cooperative game with a unique generalized Nash equilibrium (GNE). We provide a distributed algorithm which converges to the GNE. The convergence and properties of the algorithm are investigated by means of numerical simulations