48 research outputs found
Complexity of near-optimal robust versions of multilevel optimization problems
Near-optimality robustness extends multilevel optimization with a limited
deviation of a lower level from its optimal solution, anticipated by higher
levels. We analyze the complexity of near-optimal robust multilevel problems,
where near-optimal robustness is modelled through additional adversarial
decision-makers. Near-optimal robust versions of multilevel problems are shown
to remain in the same complexity class as the problem without near-optimality
robustness under general conditions
A Bilevel Approach to Optimal Price-Setting of Time-and-Level-of-Use Tariffs
Time-and-Level-of-Use (TLOU) is a recently proposed pricing policy for
energy, extending Time-of-Use with the addition of a capacity that users can
book for a given time frame, reducing their expected energy cost if they
respect this self-determined capacity limit. We introduce a variant of the TLOU
defined in the literature, aligned with the supplier interest to prevent
unplanned over-consumption. The optimal price-setting problem of TLOU is
defined as a bilevel, bi-objective problem anticipating user choices in the
supplier decision. An efficient resolution scheme is developed, based on the
specific discrete structure of the lower-level user problem. Computational
experiments using consumption distributions estimated from historical data
illustrate the effectiveness of the proposed framework
Integrating Academic and Everyday Learning Through Technology: Issues and Challenges for Researchers, Policy Makers and Practitioners
This paper builds on work undertaken over a number of years by a group of international researchers with an interest in the potential of connecting academic and everyday practices and knowledge. Drawing extensively on literature and our own work, we first discuss the challenges around defining informal learning, concluding that learning is multidimensional and has varying combinations of formal and informal attributes. We then highlight the potential of technology for integrating formal and informal learning attributes and briefly provide some exemplars of good practice. We then discuss in depth the challenges and issues of this approach to supporting learning from the perspective of pedagogy, research, policy and technology. We also provide some recommendations of how these issues may be addressed. We argue that for the learner, integration of formal and informal learning attributes should be an empowering process, enabling the learner to be self-directed, creative and innovative, taking learning to a deeper level. Given the complexity of the learning ecosystem, this demands support from the teacher but also awareness and understanding from others such as parents, family, friends and community members. We present a conceptual model of such an ecosystem to help develop further discussions within and between communities of researchers, policy makers and practitioners
A Tabu search algorithm for the network pricing problem
International audienceIn this paper, we propose an efficient Tabu Search procedure for solving the NP-hard network pricing problem. By exploiting the problem's features, the algorithm allows the near-optimal solution of problem instances that are out of reach of exact combinatorial methods
Optimal planning of autonomous electric vehicles charging stations with photovoltaic generations and energy storage systems
<p>This database contains technical information on the 69-bus electrical distribution system. This system was tested in a mixed integer linear programming model for allocating autonomous electric vehicle charging stations equipped with photovoltaic generation and energy storage systems. Additionally, this document contains data related to charging stations, energy storage systems, and operational scenarios applied to the case studies.</p>The authors acknowledge the work facilities and equipment provided by GECAD research center (UIDB/00760/2020 and UIDP/00760/2020) to the project team and CEECIND/00420/2022. Additionally, we acknowledge the collaboration of our visiting researcher (Haider Ali), who was supported by the I-SITE ULNE Foundation through the PEARL Programme for EArly-stage Researchers in Lille. The authors also acknowledge the support provided by the Thematic Network 723RT0150 (RIBIERSE-CYTED)'' financed by CYTED 2022