This paper presents a mixedintegerlinearprogramming model for sizing green hydrogen refueling station driven by a photovoltaic grid-connected system. The developed model aims to determine the capacity of the statio...
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This paper presents a mixedintegerlinearprogramming model for sizing green hydrogen refueling station driven by a photovoltaic grid-connected system. The developed model aims to determine the capacity of the station's components and the optimal configuration of the on-grid PV system. The objective is to minimize the life cycle cost of the hydrogen refueling station while considering various constraints, including the station's energy requirement, powering system reliability, land availability, and upper and lower bounds of decision variables. The effectiveness of the developed model is assessed under the weather conditions of Dhahran, Saudi Arabia. The station is estimated to produce 152 kg of hydrogen to meet the daily demand of 100 hydrogen fuel cell vehicles. A total of 1772 PV solar panels are required to meet a portion of the station's energy needs. The energy shortage is covered by the grid. The economic assessment yields that the energy cost is 0.18 $/kWh and the hydrogen cost is 4.97 $/kg. This study offers valuable insights into the efficient allocation of PVs and grid, ensuring reliable hydrogen production. The findings contribute to advancing green hydrogen infrastructure in Saudi Arabia and facilitate the transition toward greener transportation.
Historically, forestry supply chains have operated in a disjointed manner, leading to insufficient coordination between forest management and wood processing in their planning and operations. In addition, generating e...
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Historically, forestry supply chains have operated in a disjointed manner, leading to insufficient coordination between forest management and wood processing in their planning and operations. In addition, generating energy using the available resources of the forestry activity has been largely considered a secondary activity, with slight synchronization with the remaining chain. However, currently, comprehensive supply chain integration is essential for guaranteeing the economic sustainability of forest supply chains. This article presents a multi-period mixedintegerlinearprogramming (MILP) model for forest resource management, covering everything from harvesting to energy generation. It considers supply chain planning, customer selection, and both internal and external raw material sources. The model considers transportation costs, production limits, and the use of specific equipment for processing biomass and industrial waste. Importantly, it includes bioenergy generation, highlighting its economic advantages and role in the overall management of forest supply chains. Analysis of a real-world case from Misiones, Argentina, reveals that meeting wood demand consistently necessitates the exploitation of external forest stands. Moreover, the integration of on-site waste processing equipment within the stands proves economic benefits for the supply chain, whereas incorporating units for processing pulpable logs yields a comparatively smaller economic return. Notably, the study indicates that satisfying potential increases in energy demand is largely contingent on the availability of waste from external sawmills. However, in instances where external sawmill waste is scarce, the plant maintains operational continuity by utilizing alternative byproducts, such as forest biomass chips, which are typically designated for sale.
In the area of network virtualisation, virtual network embedding (VNE) refers to the resource allocation problem. In the literature, researchers have proposed multiple VNE algorithms. These algorithms have the goal of...
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In the area of network virtualisation, virtual network embedding (VNE) refers to the resource allocation problem. In the literature, researchers have proposed multiple VNE algorithms. These algorithms have the goal of accommodating as many requested virtual networks (VNs) as possible. However, most of prior embedding algorithms belong to the two-stage (separated node and link embeddings) mapping algorithm category. Certain embedding algorithms embed each VN in one mapping stage by using mixed integer linear programming approach or graph theory, having very high computation time. There is a lack of heuristic algorithms, enabling to embed nodes and links per VN in one mapping stage. In addition, each requested VN embedding needs to be completed in polynomial time so as to be promoted to future dynamic VN service application and real-time VNs embedding. Based on these backgrounds, the authors propose a novel real-time and one-stage heuristic mapping algorithm (VNE-RTOS). Numerical evaluations are conducted to strengthen that VNE-RTOS earns more embedding revenues by 8% over typical two-stage heuristic embedding algorithms (e.g. VNE-TAGRD) while achieving the same substrate resource utilisation.
In this paper, we introduce a novel optimization framework for a station-to-door mobility-on-demand system that aims at ensuring an efficient transportation service for the daily mobility of passengers in densely popu...
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ISBN:
(纸本)9781467365963
In this paper, we introduce a novel optimization framework for a station-to-door mobility-on-demand system that aims at ensuring an efficient transportation service for the daily mobility of passengers in densely populated urban areas. We propose a mixed integer linear programming approach that maximizes both the customers' satisfaction and the provider's revenues, keeping at the same time the number of vehicles in each station within given bounds towards the improvement of system balancing. The proposed customer-oriented approach aims at meeting as many customer requests as possible, while maximizing the provider revenues and reducing the customers' impatience, thus increasing their satisfaction. This implies, in turn, a better reputation for the service provider. The performance of the proposed approach is assessed through an extensive Monte Carlo simulation campaign. In particular, through the analysis of different performance indices, we compare the optimal solution of the proposed approach with the optimal solution achieved by a previously presented approach based on the Profitable Tour Problem.
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