On global minimizers of quadratic functions with cubic regularization

In this paper, we analyze some theoretical properties of the problem of minimizing a quadratic function with a cubic regularization term, arising in many methods for unconstrained and constrained optimization that have been proposed in the last years. First we show that, given any stationary point that is not a global solution, it is possible to compute, in closed form, a new point with a smaller objective function value. Then, we prove that a global minimizer can be obtained by computing a finite number of stationary points. Finally, we extend these results to the case where stationary conditions are approximately satisfied, discussing some possible algorithmic applications.Comment: Optimization Letters (2018

Renewable Hydrogen Energy Communities layouts towards off-grid operation

Solar hydrogen technology, i.e. producing green hydrogen by electrolysis fed by solar panels, is gaining attention as studies show it can compete with traditional electric batteries. Contemporary, the interest in the realization of Renewable Energy Community driven by the recent adoption in almost all the EU Countries of the RED II Directive is increasing. To match innovative technologies and new business models making the energy demand and the production closer in terms of time and space, the feasibility of Renewable Hydrogen Energy Community is explored. To determine the profitability of these solutions and size and operate the energy system, energy and economic analyses are needed as well as the optimization of its performance. A building complex with 180 kWp of PhotoVoltaics was studied using hourly real data on energy loads and production. Storage capacities ranging from 500 to 2000 kWh were simulated for hydrogen and electric battery options. The cost of investment and operation was also analyzed for the years 2020, 2030, and 2040 to evaluate changes in technology readiness level as well as accounting for the strong changes in electricity tariff due to the geopolitical issues effects on the market. The analysis was conducted using the DECAPLAN™ digital platform, which employs a mixed integer linear programming solver. Finally, the dispatch on hourly base has been compared for the same two months in 2019, 2020 and 2021 corresponding to pre, during and after pandemic restrictions

Challenges and Barriers of Wireless Charging Technologies for Electric Vehicles

Electric vehicles could be a significant aid in lowering greenhouse gas emissions. Even though extensive study has been done on the features and traits of electric vehicles and the nature of their charging infrastructure, network modeling for electric vehicle manufacturing has been limited and unchanging. The necessity of wireless electric vehicle charging, based on magnetic resonance coupling, drove the primary aims for this review work. Herein, we examined the basic theoretical framework for wireless power transmission systems for EV charging and performed a software-in-the-loop analysis, in addition to carrying out a performance analysis of an EV charging system based on magnetic resonance. This study also covered power pad designs and created workable remedies for the following issues: (i) how power pad positioning affected the function of wireless charging systems and (ii) how to develop strategies to keep power efficiency at its highest level. Moreover, safety features of wireless charging systems, owing to interruption from foreign objects and/or living objects, were analyzed, and solutions were proposed to ensure such systems would operate as safely and optimally as possible