The problem of automatic workload leveling and balancing occurring in the maintenance and inspection section of Petroleum Company in Thailand is studied, in each year, the company receives a tremendous number of ...
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ISBN:
(纸本)9781424472796
The problem of automatic workload leveling and balancing occurring in the maintenance and inspection section of Petroleum Company in Thailand is studied, in each year, the company receives a tremendous number of maintenance and inspection work orders regarding the gas and oil offshore platforms. Each worker is capable of doing more than one work order. Workload leveling is needed in order to distribute all works for limited number of personnel and accommodations on offshore platform. mixedintegerlinearprogramming (MILP) technique using branch and cut method is utilized for this problem.
Cellular manufacturing systems (CMS) are production systems that typically comprise a number of manufacturing cells served by a centralized material handling system. Designing such systems includes three major decisio...
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Cellular manufacturing systems (CMS) are production systems that typically comprise a number of manufacturing cells served by a centralized material handling system. Designing such systems includes three major decisions; cell formation (CF), group layout (GL), and group scheduling (GS). Traditionally, these three decisions have been dealt with separately, which has usually lead to less than optimal system performance. In this paper, a new mixed integer linear programming (MILP) model is proposed for the integrated CF, GL and GS problem, to efficiently design and operate CMSs. The model solves the integrated problem, taking into consideration intercellular and intracellular transportation times to determine the optimal cell formation, layout of machines and schedule of parts on the machines, simultaneously. Sequence-dependent set up times are also considered in the model. The performance of the model is tested by solving problems previously introduced in the literature considering two objectives; minimizing the makespan or minimizing the mean flow time in the system. The results show that the proposed model is efficient in solving small to medium-sized problems.
The optimal trajectory planning for trains under constraints and fixed maximal arrival time is considered. The variable line resistance (including variable grade profile, tunnels, and curves) and arbitrary speed restr...
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ISBN:
(纸本)9781457721977
The optimal trajectory planning for trains under constraints and fixed maximal arrival time is considered. The variable line resistance (including variable grade profile, tunnels, and curves) and arbitrary speed restrictions are included in this approach. The objective function is a trade-off between the energy consumption and the riding comfort. First, the nonlinear train model is approximated by a piece-wise affine model. Next, the optimal control problem is formulated as a mixed integer linear programming (MILP) problem, which can be solved efficiently by existing solvers. The good performance of this approach is demonstrated via a case study.
This paper proposes a novel method for determining the optimal number of renewable energy and storage components in a microgrid given typical load profiles, local pricing regime, and capital costs. Case studies using ...
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ISBN:
(纸本)9781479956159
This paper proposes a novel method for determining the optimal number of renewable energy and storage components in a microgrid given typical load profiles, local pricing regime, and capital costs. Case studies using solar panels and advanced lead acid battery modules are performed under residential, commercial, and off-grid sites. Simple mixed integer linear programming (MILP) optimization problems are formulated, presented, and solved in each scenario where economic analysis highlights the utility of the proposed approach.
Optimization of charging profiles for controlled charging of electric vehicles is commonly done via mixed integer linear programming. The runtime of the optimization can represent an issue for the practical use. Howev...
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ISBN:
(数字)9783030437220
ISBN:
(纸本)9783030437213;9783030437220
Optimization of charging profiles for controlled charging of electric vehicles is commonly done via mixed integer linear programming. The runtime of the optimization can represent an issue for the practical use. However, by tuning the parameter setting of the employed solver, it is possible to speed up the optimization process. The present work evaluates two popular hyperparameter tuning tools - irace (iterated racing) and SMAC (sequential model-based algorithm configuration) - for the optimization of parameters of the SCIP (Solving Constraint integer Programs) solver with the objective to speed up the solving process for four common variants of the electric vehicle charging scheduling problem. Based on the results, the most important solver parameters are identified. It is shown that by tuning a very limited number of parameters, speed-ups of 60% and more can be achieved.
Wavelength division multiplexing network is a method to improve capacity of transmission and to design the best path between the source and destination and assign the wavelength to the path for data transmission. A si...
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ISBN:
(纸本)9781479913565
Wavelength division multiplexing network is a method to improve capacity of transmission and to design the best path between the source and destination and assign the wavelength to the path for data transmission. A simple node is to be designed with mixed integer linear programming /GPLK 4.4 as the mathematical problem formulation for the single-hop and virtual hop of the network. Comparison of the topologies, INTERNET, EON and National Science Foundation Network (NSFNET) With Wavelength Division Multiplexing Conversion having different light-path flows is made for different number of nodes with capacity and average Ingress, Egress and groomed traffic. The performance metrics is determined by Wavelength of Light paths, single hop path, Number of Virtual hops, Network Congestion, Number of Wavelength per link, and Wavelength channel capacity.
In this paper, we consider the problem of localizing the subsequence in time series which contains the dynamic pattern of interest. This is motivated by brain computer interface application where we need to analyze th...
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ISBN:
(纸本)9781538637883
In this paper, we consider the problem of localizing the subsequence in time series which contains the dynamic pattern of interest. This is motivated by brain computer interface application where we need to analyze the dynamic pattern of brain signals in response to external stimulus. We treat the localization as a binary label assignment problem and formalize a mixed integer linear programming (MILP) problem. The optimal solution is obtained by minimizing a cost function associated with label assignment subject to empirical constraints induced by data acquisition process. We first experiment with synthetic data to evaluate the effectiveness of the proposed MILP formulation and achieve 10.8 % improvement on F-1-score. We then experiment with electrocorticographic (ECoG) data for a classification task and achieve 8.8 % improvement on accuracy using subsequences localized by our method compared to other methods.
With the ever growing number of technologies that interact with the grid, optimization and control strategies become critical to ensure the quality of service without disruption. This work analyses the application of ...
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A large part of the services provided on the Internet resides in virtualized environments of 'cloud' providers, whose IT infrastructures adopt, for the most part, the containers virtualization technique to hou...
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The energy sector is transitioning from heavy reliance on fossil fuels to focus on renewable energy production. This transition requires decarbonization of district heating. For Fortum, one of the largest heat produce...
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The energy sector is transitioning from heavy reliance on fossil fuels to focus on renewable energy production. This transition requires decarbonization of district heating. For Fortum, one of the largest heat producers in the world, this is an important strategic focus. To achieve decarbonization of district heating systems in a profitable and low risk way, advanced tools for decision making and risk analysis are required.
To answer for this need, this thesis aims to investigate how advanced MILP models created with the Fortum MONA tool can be used in a Monte Carlo simulation-based investment analysis process. To capture uncertainties in key input variables as accurately as possible, stochastic models for temperature and electricity spot prices are developed. An investment analysis process is created and tested by conducting a case study on a large heat pump investment in the Fortum Espoo district heating system.
The results of the case study indicate that the developed investment analysis process succeeds in conveying a comprehensive view on investment risk and profitability, and that MONA models can successfully be used in this type of analysis. However, multiple challenges are identified, which must be overcome in order for the analysis process to be taken into wide use in Fortum. The greatest challenges are related to computation time and issues with local processing. To tackle these challenges, it is recommended that in the future, cloud computing should be utilized to run the process. In addition, development of more stochastic models for uncertain variables is suggested, in order to capture all relevant uncertainties related to an investment.
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