mixed integer linear programming is a powerful and widely used approach to solving optimization problems, but its expressiveness is limited. In this paper we introduce the optimization-aided language SCIMITAR, which e...
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ISBN:
(纸本)9798400712159
mixed integer linear programming is a powerful and widely used approach to solving optimization problems, but its expressiveness is limited. In this paper we introduce the optimization-aided language SCIMITAR, which encodes optimization problems using an expressive functional language, with a compiler that targets a mixedintegerlinear program solver. SCIMITAR provides easy access to encoding techniques that normally require expert knowledge, enabling solve-time conditional constraints, inlining, loop unrolling, and many other high-level language constructs. We give operational semantics for SCIMITAR and constraint encodings of various features. To demonstrate SCIMITAR, we present a number of examples and benchmarks including classic optimization domains and more complex problems. Our results indicate that SCIMITAR's use of a dedicated MILP solver is effective for expressively modeling optimization problems embedded within functional programs.
Columnar database systems can process complex mixed workloads on a single node. In case of increasing and peak analytical processing demand, we can offload read-only queries to replicas. Partial replication, i.e., dup...
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ISBN:
(纸本)9798400704369
Columnar database systems can process complex mixed workloads on a single node. In case of increasing and peak analytical processing demand, we can offload read-only queries to replicas. Partial replication, i.e., duplicating only data subsets to additional nodes, is more cost-efficient than full replication for two primary reasons: (i) Partial replicas require less storage and can be set up faster. (ii) Partial replicas must synchronize only stored data subsets, allowing better scalability. However, determining which queries to offload is challenging for larger workloads because queries access overlapping data subsets and cause synchronization costs. This paper shows how to calculate optimized replica configurations that consider reallocation and data modification costs using integerlinearprogramming (ILP) techniques. While ILP is effective for solving assignment problems, it does not scale well. For larger problems, users often fall back to simple heuristics, which can lose optimization potential. This paper demonstrates that scalable heuristics can be built on ILP, preserving its strengths. The three proposed approaches for reducing the calculation time allow trading solution quality flexibly. Our evaluations using TPC-H, TPC-DS, and a large real-world accounting workload show that our approach outperforms state-of-the-art solutions, often reducing re=allocated data by more than 80% and halving modification costs. At the same time, the new allocations reduce the storage consumption by over 30%, with solutions computed in just a few seconds.
This paper considers an M-pursuer N-evader scenario involving virtual targets. The virtual targets serve as an intermediary target for the pursuers, allowing the pursuers to delay their final assignment to the evaders...
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ISBN:
(数字)9781624107115
ISBN:
(纸本)9781624107115
This paper considers an M-pursuer N-evader scenario involving virtual targets. The virtual targets serve as an intermediary target for the pursuers, allowing the pursuers to delay their final assignment to the evaders. However, upon reaching the virtual target, the pursuers must decide which evader to capture. It is assumed that there are more pursuers than evaders and that the pursuers are faster than the evaders. The objective is two-part: first, assign each pursuer to a virtual target and evader such that the pursuer team's energy is minimized, and second, choose the virtual targets' locations for this minimization problem. The approach taken is to consider the Apollonius geometry between each pursuer's virtual target location and each evader. Using the constructed Apollonius circles, the pursuer's travel distance and maneuver at a virtual target are obtained. These metrics serve as a gauge for the total energy required to capture a particular evader and are used to solve the joint virtual target selection and pursuer-evader assignment problem. This paper provides a mathematical definition of this problem, the solution approach taken, and an example.
This study considers a problem of coordinating production, transportation and sales in a multi-echelon supply chain network. A simulation model is built to generate the random customer demands at different locations, ...
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This study considers a problem of coordinating production, transportation and sales in a multi-echelon supply chain network. A simulation model is built to generate the random customer demands at different locations, which are affected by a marketing strategy. Customer demands need to be satisfied by the supply chain through production, transportation and distribution. The optimization problem for coordination of production, transportation and distribution is first formulated as a linearprogramming with demands as input parameters in the constraint. Our objective is to maximize the expectation of the optimal profit of the supply chain given random demands by selecting an optimal marketing strategy. A simulation optimization technique is proposed to control the generation of random demands and solve the linearprogramming for efficiently learning the optimal marketing strategy. Numerical results show that our method can significantly improve the expected profit of the supply chain and reduce the computational burden of solving linearprogramming for achieving a given level of probability of correct selection of the optimal marketing strategy. Furthermore, we extend the optimization problem to a mixedintegerprogramming and also demonstrate the computational efficiency of our proposed method.
Recognizing the growing global threat of air pollution, transit agencies and governments across the world are focusing on switching to electric vehicles (EVs). Battery electric buses (BEB) are becoming a crucial compo...
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Recognizing the growing global threat of air pollution, transit agencies and governments across the world are focusing on switching to electric vehicles (EVs). Battery electric buses (BEB) are becoming a crucial component to plan a sustainable transportation system. Two biggest drawbacks of BEBs are range anxiety and higher charging time. To overcome these hurdles, decision-makers are required to execute strategic decisions such as planning and design of charging locations as well as operational decisions like scheduling the charging activities for BEBs. This study gives insight into the planning and design of charging infrastructure network for BEBs while minimizing the total annual cost of designing the BEB system Apart from this, this study also focuses on the scheduling part for BEBs and provide information on the occurrence of charging activities for BEBs. A mixed-integerlinearprogramming model is formulated which models the trade-off between route-specific battery capacity and terminal-level charging power (charger size along with the number of chargers at a terminal) and generates a scheduling plan for charging the BEBs. A part of New Delhi's public bus network identified for electrification (18 bus routes and 21 terminal stations) by its transit agency was selected for our model application. Results suggested that model was able to obtain trade-off between battery size allocation and charger size selection.
Demand response manages energy demand to match available energy in the smart grid. Residential community loads in the smart grid are diverse and flexible. To integrate user preferences with demand response scheduling ...
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ISBN:
(纸本)9798350387780;9798350387797
Demand response manages energy demand to match available energy in the smart grid. Residential community loads in the smart grid are diverse and flexible. To integrate user preferences with demand response scheduling for residential communities, a centralized demand response scheduling algorithm is proposed. In this paper, user willingness price is first introduced through fuzzy c-means to quantify user preferences. Secondly, a complete residential community DR scheduling algorithm is established based on use preference and mixed integer linear programming to minimize the total energy cost of the residential community. Simulation results show that the proposed algorithm can reduce the total energy cost of the residential community and communication traffic.
This paper proposes a study motivated by the problem of minimizing the environmental impact of air transport considering the complete air network, thereby several aircraft. Both CO2 and non-CO2 effects are taken into ...
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This paper explores three new competitive heuristic procedures, which are compared with the mixed integer linear programming (MILP), all used to commit units within a hydroplant to give the maximal electrical producti...
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This paper explores three new competitive heuristic procedures, which are compared with the mixed integer linear programming (MILP), all used to commit units within a hydroplant to give the maximal electrical production during a study horizon, given the cascade operation has already determined the quarter-hourly releases from individual reservoirs. The problem incorporates constraints on the unit up/down hours and its shutdown times. The procedures are applied to seven hydroplants, with 2, 3, 4, 5, 6, 9 and 18 units installed respectively. The application suggests that the MILP performs the best in minimizing spillages and improving generating efficiency but volatile in computation time when the number of units is more than 4 in a hydroplant, while the heuristic procedures can obtain fairly good results and have a significant advantage in computation time when committing more than 6 units in a hydroplant. The heuristic procedures are valuable when incorporating unit commitment into a large-scale operational problem of cascaded hydropower reservoirs. (C) 2022 The Authors. Published by Elsevier Ltd.
We consider a Job Shop Scheduling Problem with transport (JSPT) which consists in jointly scheduling machines and robots. In contrast with the literature, we assume that a transport operation may involve several robot...
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ISBN:
(纸本)9783031629112;9783031629129
We consider a Job Shop Scheduling Problem with transport (JSPT) which consists in jointly scheduling machines and robots. In contrast with the literature, we assume that a transport operation may involve several robots simultaneously, which requires resource synchronization over time. We formulate this problem as a mixed integer linear programming (MILP) formulation. Then we propose a GRASP-ELS meta-heuristic and a local search procedure where we use a Bierwith's sequence approach to evaluate a solution. In a numerical study, we have adapted instances from the literature to our problem. The meta-heuristic competes with the exact resolution providing high quality solution in reduced computation time, which lead us to consider that both the modeling and local search are accurate.
Restoring a power system following a blackout is a critical undertaking, necessitating the efficient allocation of Black Start (BS) resources-generators capable of initiating without external power. This research intr...
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ISBN:
(纸本)9798350372410;9798350372403
Restoring a power system following a blackout is a critical undertaking, necessitating the efficient allocation of Black Start (BS) resources-generators capable of initiating without external power. This research introduces an innovative approach to address a critical challenge in power system restoration-optimal black start allocation. Efficient allocation of resources when power systems face blackouts is crucial for rapid restoration. Leveraging the power of mixed integer linear programming (MILP), this study formulates and solves the black start allocation problem with the primary objective of minimizing allocation costs, all while satisfying many operational constraints. These constraints include ensuring power supply meets demand, adhering to generator output limits and ramping rates, and enforcing time-bound generator startup decisions. Furthermore, it maintains power flow equilibrium and network stability through branch flow and voltage magnitude constraints. This research offers a promising solution to enhance the resilience and reliability of power systems by optimizing the allocation of black start resources. This would reduce downtime ultimately and mitigate the far-reaching impacts of blackouts on society and the economy.
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