1,720,958 research outputs found
A Noncooperative Stochastic Rolling Horizon Control Framework for V1G and V2B Scheduling in Energy Communities
No full textIn this paper, we propose a novel control strategy for the optimal scheduling of an energy community constituted by prosumers and equipped with unidirectional vehicle-to-grid (V1G) and vehicle-to-building (V2B) capabilities. In particular, V2B services are provided by long-term parked electric vehicles (EVs) thus acting as temporary storage systems by prosumers, which in turn offer the V1G service to EVs provisionally plugged into charging stations. To tackle the stochastic nature of the framework, we assume that EVs communicate their parking and recharging time distribution to prosumers, allowing them to improve their energy allocation. Prosumers and EVs interact in a rolling horizon control framework with the aim of achieving an agreement on their operating strategies. The resulting control problem is formulated as a generalized Nash equilibrium problem, addressed through the variational inequality theory, and solved in a distributed fashion leveraging on the accelerated distributed augmented Lagrangian method (ADALM). The convergence and effectiveness of the proposed approach are validated through numerical simulations under realistic scenarios
Optimal Decision Strategies for the Generalized Cuckoo Card Game
No full textCuckoo is a popular card game, which originated in France during the 15th century and then spread throughout Europe, where it is currently well-known under distinct names and with different variants. Cuckoo is an imperfect information game-of-chance, which makes the research regarding its optimal strategies determination interesting. The rules are simple: each player receives a covered card from the dealer; starting from the player at the dealer's left, each player looks at its own card and decides whether to exchange it with the player to their left, or keep it; the dealer plays at last and, if it decides to exchange card, it draws a random one from the remaining deck; the player(s) with the lowest valued card lose(s) the round. We formulate the gameplay mathematically and provide an analysis of the optimal decision policies. Different card decks can be used for this game, e.g., the standard 52-card deck or the Italian 40-card deck. We generalize the decision model for an arbitrary number decks' cards, suites, and players. Lastly, through numerical simulations, we compare the determined optimal decision strategy against different benchmarks, showing that the strategy outperforms the random and naive policies and approaches the performance of the ideal oracle
An Optimization Tool for Displacing Photovoltaic Arrays in Polygonal Areas
No full textIn this paper, we discuss the problem of optimally designing the layout of a given number of photovoltaic arrays on a flat polygonal surface, in order to maximize a suitable objective function, e.g., the total generated energy. This means finding their optimal position, azimuth and tilt. The considered problem becomes non-trivial when considering effects such as irradiance variability and self-shadowing. We first provide a description of the system model and the associated optimization problem, showing how the resulting formulation presents non-convexities. Then, we provide a tight parametrized convex relaxation, which is computationally tractable and for which optimality conditions hold. We provide numerical simulations using realistic data, showing how the proposed methodology yields near-optimal solutions in lower computational time with respect to the traditional global resolution approach
Game Theoretical Control Frameworks for Multiple Energy Storage Services in Energy Communities
No full textIn the last decade, distributed energy generation and storage have significantly contributed to the widespread of energy communities. In this context, we propose an energy community model constituted by prosumers, characterized by their own demand and renewable generation, and service-oriented energy storage providers, able to store energy surplus and release it upon a fee payment. We address the problem of optimally schedule the energy flows in the community, with the final goal of making the prosumers' energy supply more efficient, while creating a sustainable and profitable business model for storage providers. The proposed resolution algorithms are based on decentralized and distributed game theoretical control schemes. These approaches are mathematically formulated and then effectively validated and compared with a centralized method through numerical simulations on realistic scenarios
A Markowitz Optimization Approach for Automating the Italian Research Quality Monitoring and Evaluation
No full textThis paper presents a selection-supporting framework which can help research institutions to optimally and automatically pool the research products for research quality assessment programs, with a specific focus on the Italian evaluation process (VQR). After providing a mathematical description of the VQR exercise at the institutional level, we formulate the robust optimization problem which yields the optimal pair of research products and associated authors. We show how such a formulation quickly becomes unpractical, due to combinatorial issues, and propose a novel Markowitz-based alternative approach, which preserves computational feasibility and effectiveness. We strive to propose a reusable framework, not too tightly connected to the ruleset of the current VQR session (2020-2024). Finally, we validate the proposed framework on a synthetic set of parameters, which mimics a medium-sized research institution, with the aim of checking the computational feasibility of the proposed Markowitz-based variants
Generalized Nash Equilibrium Seeking for Crop Mix Selection in Sustainable Agriculture
No full textSince diversifying crop selection can significantly optimize resources, increase resilience to climate change, and contribute to sustainable development, decision-making tools are crucial to help farmers identify optimal crop cultivation strategies. This paper proposes a novel optimization framework for crop mix selection under the non-cooperative game-theoretical perspective, i.e., assuming that the agents (e.g., farmers and agriculture companies) behave selfishly. Such a perspective naturally arises when multiple agents are competing for shared resources, such as water, land, and carbon emissions quotas. First, we illustrate the system model, comprising both local and global resource constraints that the crop mix strategy of all agents must abide by. Then, we characterize the Generalized Nash Equilibrium problem stemming from such a formulation, providing an iterative equilibrium-seeking approach based on the consolidated operator splitting framework. Finally, we numerically test the proposed framework using real-world data
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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