Investigations regarding means to achieve savings in primary energy use and to decrease anthropogenic CO2 emissions have shown that improved energy efficiency has potential to offer a significant contribution to this ...
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ISBN:
(纸本)9788895608266
Investigations regarding means to achieve savings in primary energy use and to decrease anthropogenic CO2 emissions have shown that improved energy efficiency has potential to offer a significant contribution to this cause. Considering energy networks and systems, improvements can be achieved by optimizing the structure of the energy chains and distribution networks. For instance, in the case of district heating, it is possible to find an optimal choice of energy supply and design of piping networks to provide the energy required by the customers. Additionally, heat storages and local small-scale energy contributions from e. g. heat pumps could provide benefits and should be taken into consideration. the complexity of the optimization problem increases when the choices of technologies and capacities as well as the network topologies need to be considered. Furthermore, a level of intricacy is added by the large differences in energy demand and temperature conditions between day and night and different seasons. A mixed-integer linear programming model for optimizing distributed energy systems, which takes into account the above mentioned aspects, is being developed and is presented herein. the model is tested with a case study concerning district heating in a locality in southern Finland.
maxsat is an optimization version of satisfiability. Since many practical problems involve optimization, there are a wide range of potential applications for effective maxsat solvers. In this paper we present an exten...
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this paper addresses the energy management of large-scale urban street lighting systems. We propose a multi-stage decision-making procedure that supports the energy manager in determining the optimal energy retrofit p...
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this paper addresses the energy management of large-scale urban street lighting systems. We propose a multi-stage decision-making procedure that supports the energy manager in determining the optimal energy retrofit plan of an existing public street lighting system. the problem statement is based on a quadratic integerprogramming formulation and aims at simultaneously reducing the energy consumption, ensuring an optimal allocation of the retrofit actions, and efficiently using the available budget. the proposed solution relies on a decentralized optimization algorithm that is based on discrete dynamic programming. the methodology is applied to a real street lighting system in the city of Bari, Italy.
We study resource constrained scheduling problems where the objective is to compute feasible preemptive schedules minimizing the makespan and using no more resources than what are available. We present approximation s...
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the multi-stage renewal planning problem is studied here for an energy supply system installed into a hospital from the long- Term economic viewpoint by applying the mathematical optimization method. this problem is m...
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ISBN:
(纸本)9782955553909
the multi-stage renewal planning problem is studied here for an energy supply system installed into a hospital from the long- Term economic viewpoint by applying the mathematical optimization method. this problem is mathematically formulated as a large-scale mixed-integer linear programming one, and the average annual total cost during the evaluation period is set as the objective function to be minimized. In this problem, by taking the deterioration of performance efficiency of the existing pieces of equipment, the renewal system is assumed to be composed by installing new pieces of equipment with improved efficiency by reflecting technical progress. By optimizing the system's operational policy for hourly and seasonally changing energy demands through years of the evaluation period, the renewal years and the system's configurations at each multi-stages are determined optimally. A numerical study is carried out for a really existing hospital with total floor area of 25000m2, and many comprehensive and useful results are obtained by comparing 13 alternative renewal plans by using the CPLEX solver.
the development and research of discrete optimization models with logical, resource and other constraints to solve complex products design problems are continued in the article. these models are based on the SAT probl...
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Fully automated sorting equipment plays a crucial role in modern distribution networks of the parcel service industry, and the efficiency of the sorting scheme is crucial for the sorting equipment. this study optimize...
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ISBN:
(纸本)9789811386831;9789811386824
Fully automated sorting equipment plays a crucial role in modern distribution networks of the parcel service industry, and the efficiency of the sorting scheme is crucial for the sorting equipment. this study optimizes the sorting scheme for a type of double-layer sorting equipment, which adapts "component-sorting" strategy. "Component-sorting" refers to the method of sorting multiple parcels sent to the same destination by the same tray. the problem is formulated as an integerprogramming model. then, we propose an efficient variable neighbor taboo search to solve the problem within a short time. the experimental results show that the proposed solution method is suitable for solving the problem of interest.
We introduce a two-machine flow shop scheduling problem under linear constraints (2-FLC problem in short), in which the processing times of two stages of jobs are also decision variables and satisfy a system of linear...
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In this paper, we study the maximum coverage problem with group budget constraints (MCG) that generalizes the maximum coverage problem. Given a ground set U in which i E U has a non-negative weight w,, a positive inte...
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ISBN:
(纸本)9783319711478;9783319711461
In this paper, we study the maximum coverage problem with group budget constraints (MCG) that generalizes the maximum coverage problem. Given a ground set U in which i E U has a non-negative weight w,, a positive integer k and a collection of sets S, the maximum coverage problem is to pick k sets of S to maximize the total weight of their union. In MCG, S is partitioned into groups g1,, c and the goal is to pick k sets from S to maximize the total weight of their union, with at most ni E Z sets being picked from group ci. For MCG with n,/ = 1, Vi, we first present a factor 1 eapproximation algorithm which runs in exponential time. then we improve the runtime of the algorithm to 0 ( (m n q)3.5 L k3.5 q7 L) where 1,51 = m, =12, q is the number of groups, and L is the length of the input. the key idea of the improvement is to model selecting groups for MCG as computing a constrained flow in a corresponding auxiliary graph. It is also shown that the algorithm can be extended to solve MCG with general ni. Later, based on the main idea of partition we further improve the runtime of the algorithm to 0((m n q)3.5 L k(51.5 L), while compromise the approximation ratio to 1 e+-5-1, where (5 > 2 is any fixed integer. Consequently, we can balance approximation ratio and runtime of the algorithm by setting the value of S. this improves the previous best ratio of 0.5 on MCG due to Chekuri and Kumar [4].
the best exact algorithms for the Capacitated Vehicle Routing Problem (CVRP) have been based on either branch-and-cut or Lagrangean relaxation/column generation. this paper presents an algorithm that combines both app...
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