The transition to a carbon-neutral power system requires replacing conventional generation with distributed renewable energy (RE) sources. This poses challenges related to reduced system inertia and large and long-dis...
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ISBN:
(数字)9798350390421
ISBN:
(纸本)9798350390438
The transition to a carbon-neutral power system requires replacing conventional generation with distributed renewable energy (RE) sources. This poses challenges related to reduced system inertia and large and long-distance power transmission in the system. This paper presents a novel generation expansion planning (GEP) methodology called inertia-aware clustered generation expansion planning (I-CGEP). The I-CGEP approach integrates spatial clustering and generator clustering to optimize discrete generation expansion options while avoiding overestimation of system inertia. The model incorporates advanced Rate of Change of Frequency (RoCoF) constraints that, in addition to standard constraints following predefined outages, also account for the expected power imbalance resulting from large disturbance scenarios such as regional islanding. The entire problem is formulated as a mixed-integerlinearprogramming (MILP) problem. The proof of concept of the methodology is demonstrated using the open European transmission system model PyPSA-Eur. The results show its suitability for maintaining the required RoCoF under different scenarios.
Operations research is usually employed to solve the facility location problem, mainly using mixed integer linear programming (MILP). Meanwhile, some MILP models were not originally designed to solve a large class of ...
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Operations research is usually employed to solve the facility location problem, mainly using mixed integer linear programming (MILP). Meanwhile, some MILP models were not originally designed to solve a large class of location problems, corresponding to those where customers are served in a routing operation. In this case location and routing decisions are strongly interrelated. Moreover, this modeling approach has the difficult of facing a NP-hard problem situation, which means a very high algorithm complexity. Therefore, for large-scale problems the computational times are practically infeasible. This paper has developed an alternative method using a hybrid approach to solve the location problem, taking into account these two aspects: the NP- hard situation and the routing operation. The suggestion is to decompose the problem through a clustering procedure applied to the demand points, followed by the application of an optimization model to each cluster. The proposal appeared to be effective when applied to a set of test problems used on a conducted experiment designed to validate the method.
The adoption of Electric Vehicles(EVs) is growing because of their environment-friendly properties and more efficient, With the increasing shift toward EVs, the need for a robust and well-coordinated charging infrastr...
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ISBN:
(数字)9798350367065
ISBN:
(纸本)9798350367072
The adoption of Electric Vehicles(EVs) is growing because of their environment-friendly properties and more efficient, With the increasing shift toward EVs, the need for a robust and well-coordinated charging infrastructure has become critical. The current lack of sufficient Fast Charging Stations (FCS) poses a significant challenge to supporting widespread EV usage. Proper planning of charging stations, both in terms of location and capacity, is essential to accommodate rising EV demand. Complicating this process is the interdependence between Transportation Networks (TN) and Power Distribution Networks (PDN), which requires a unified approach for efficient large-scale EV integration. This paper introduces a coordinated planning approach for integrating EV charging stations within both TN and PDN frameworks. A detailed optimization model is presented to identify the optimal locations and capacities for charging stations based on EV traffic patterns and power network capabilities. The traffic flow across the transportation network is modelled using an unconstrained traffic assignment method, while the PDN is represented through a linearized power flow model. To capture the complex interactions between TN and PDN, the model employs a mixed-integerlinearprogramming (MILP) framework that incorporates constraints from both networks. Through simulations on coupled traffic and power networks, the proposed approach demonstrates its effectiveness in optimizing EV charging infrastructure, facilitating a smoother transition to electric mobility.
Summary from only given. This paper presents a hierarchical demand response (DR) bidding framework in the day-ahead energy markets which integrates customer DR preferences and characteristics in the ISO's market c...
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Summary from only given. This paper presents a hierarchical demand response (DR) bidding framework in the day-ahead energy markets which integrates customer DR preferences and characteristics in the ISO's market clearing process. In the proposed framework, load aggregators submit aggregated DR offers to the ISO which would centrally optimize final decisions on aggregators' DR contributions in wholesale markets. The hourly load reduction strategies include load shifting and curtailment and the use of onsite generation and energy storage systems. The ISO applies mixed-integerlinearprogramming (MILP) to the solution of the proposed DR model in the day-ahead market clearing problem. The proposed model is implemented using a 6-bus system and the IEEE-RTS, and several studies are conducted to demonstrate the merits of the proposed DR model.
This work presents a mathematical programming formulation for the static Bike Rebalancing Problem to meet the practical constraints faced by the operators of Bike Sharing Systems. Adaptating a mixedintegerlinear Pro...
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This work presents a mathematical programming formulation for the static Bike Rebalancing Problem to meet the practical constraints faced by the operators of Bike Sharing Systems. Adaptating a mixed integer linear programming formulation, it now includes different types of vehicles and bicycles, the autonomy of each vehicle, the duration of its route and the stations that require inspection actions. An intermediate station is introduced to temporarily store bicycles, relaxing the restrictions imposed by the vehicles' capacity. After incorporating different acceleration procedures, a Branch-and-Cut scheme is run for 30 min to find optimized routes for the reposition vehicle on five real instances of the Lisbon Bike Sharing System. The computed routes resulted in a 30% to 75% decrease in total length, when compared to the real routes. This decrease is mainly attributed to the integration of all the mentioned factors in one global model, encouraging its future implementation.
This paper considers a single-machine scheduling problem to minimize the total weighted completion time with a weight modifying activity, after which the job weights are discounted by a given factor. The problem is kn...
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In proposing an integrated production-distribution model for multinational corporations (MNC), the current research undertakes a novel, simultaneous consideration of facility location, capacity acquisition/disposal, l...
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In proposing an integrated production-distribution model for multinational corporations (MNC), the current research undertakes a novel, simultaneous consideration of facility location, capacity acquisition/disposal, labor, manufacturing, purchasing, exchange rates, tariffs, and container and/or individual shipping factors. Unlike prior studies that examined some such factors. Based on real-world data from a window manufacturing MNC, a mixed integer linear programming model is developed and solved using CPLEX Solver. It reveals how the different features affect the base solution. Specifically, increased demand pushes more manufacturing to US and UK facilities rather than (low-cost) Chinese facilities;it helps meets some of China's demand and leads to reduced total tariff costs. Decreased demand instead favors the Chinese facility, and the increase in tariff costs can be offset by savings in manufacturing and transportation costs. Changes to the factors have insignificant effects on the production and distribution mix, with little to no impact on total profits, because these costs are lower than capacity costs. The comprehensive proposed model provides firms with a framework for obtaining meaningful insights into how they can maintain their operations in sustainable, profitable ways. This research also should assist policymakers in making informed decisions regarding regulations on production and distribution strategies.
Manufacturers often dispatch jobs in batches to reduce delivery costs. However, this technique can have a negative effect on other scheduling-related objective functions such as minimising maximum tardiness. This pape...
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We present a new scheduling approach to improve access to care at an inner-city community health centre in Vancouver, Canada, serving marginalised clients with complex biopsychosocial needs. In order to meet the speci...
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We present a new scheduling approach to improve access to care at an inner-city community health centre in Vancouver, Canada, serving marginalised clients with complex biopsychosocial needs. In order to meet the specific care needs of clients, the centre provides a range of services on a booked and walk-in basis, and it is important that clients are seen in a timely manner. To align schedules with client demand, we developed a schedule optimisation model that maximises time nurses spend with clients. This new objective function allows for a simple mixed integer linear programming structure that directly incorporates carryover demand. Client-centred key performance indicators were evaluated using a discrete event simulation model. Optimisation aligns schedules to demand, leading to fewer clients who leave without being seen due to an extended wait. This increases the number of clients receiving care by up to 9 per week, without compromising wait times. Furthermore, our approach addresses service delivery concerns, including baseline nurse coverage for triage and weekly variability in total nurse hours. Strategically aligning nurse shifts to demand is an effective approach to better meet client needs without increasing total nurse staffing levels in a community health centre context. (C) 2021 Elsevier Ltd. All rights reserved.
The p-regions is a mixedintegerprogramming (MIP) model for the exhaustive clustering of a set of n geographic areas into p spatially contiguous regions while minimizing measures of intraregional heterogeneity. This ...
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The p-regions is a mixedintegerprogramming (MIP) model for the exhaustive clustering of a set of n geographic areas into p spatially contiguous regions while minimizing measures of intraregional heterogeneity. This is an NP-hard problem that requires a constant research of strategies to increase the size of instances that can be solved using exact optimization techniques. In this article, we explore the benefits of an iterative process that begins by solving the relaxed version of the p-regions that removes the constraints that guarantee the spatial contiguity of the regions. Then, additional constraints are incorporated iteratively to solve spatial discontinuities in the regions. In particular we explore the relationship between the level of spatial autocorrelation of the aggregation variable and the benefits obtained from this iterative process. The results show that high levels of spatial autocorrelation reduce computational times because the spatial patterns tend to create spatially contiguous regions. However, we found that the greatest benefits are obtained in two situations: (1) when n/p >= 3;and (2) when the parameter p is close to the number of clusters in the spatial pattern of the aggregation variable.
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