Predictive and prescriptive techniques are being evaluated to predict demand for inpatient services within South East Wales. This work is specifically focusing on multi-site hospital services for elderly and frail pat...
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ISBN:
(数字)9781665468459
ISBN:
(纸本)9781665468459
Predictive and prescriptive techniques are being evaluated to predict demand for inpatient services within South East Wales. This work is specifically focusing on multi-site hospital services for elderly and frail patients, using classification and regression trees to determine patient clusters with similar attributes, yielding results of up to 89.62% accuracy. By incorporating these results into mathematical models we aim to quantify the value of incorporating the clustering results in a deterministic and stochastic mathematical programme.
Decision-making in complex systems is undoubtedly quite difficult, mostly under exceptional circumstances. Indeed, in the context of international market selection, the COVID-19 pandemic has made pharmaceutical export...
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ISBN:
(纸本)9781665427357
Decision-making in complex systems is undoubtedly quite difficult, mostly under exceptional circumstances. Indeed, in the context of international market selection, the COVID-19 pandemic has made pharmaceutical export decisions more complex. Several scientific approaches are used by researchers as well as practitioners to guide in this area. In particular, Operations Research techniques, including linear programming, discrete event simulation and queuing theory, are called by organizational leaders to make high-quality decisions. This study presents a Benchmarking methodology to support the decision-making process for international market selection based on the Data Envelopment Analysis method. A computational numerical study was conducted to highlight the performance of the proposed approach.
In recent years,China's dry ports have entered into a period of rapid development,especially driven by the Belt and Road initiative(BRI).This initiative not only provides valuable opportunities,but also intensifie...
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In recent years,China's dry ports have entered into a period of rapid development,especially driven by the Belt and Road initiative(BRI).This initiative not only provides valuable opportunities,but also intensifies fierce competition between *** order to earn more profits and maintain an advantageous position,dry ports generally tend to rely on seaports to increase competitiveness and attract more goods,and seaports are also willing to cooperate with dry ports to expand their *** a large coastal province in China,Shandong Province has good maritime *** of the fierce competition among seaports inside and outside Shandong Province,port operators should make good use of the opportunity offered by BRI to make connections with the inland cities through the dry port-seaport logistics network and enhance the *** order to take an active part in the process of the BRI,forming a dry port-seaport logistics network is a win-win strategy for Shandong *** research first analyzes the impact of the Belt and Road initiative on ports of Shandong and its development,then uses complex network theory and TOPSIS method to select dry port candidate cities from BRI's important transportation *** considering economic benefits,carbon emissions and construction costs,a multi-objective optimization model is established with a construction cost preference *** the NSGA-II algorithm is used to solve the realistic *** study finds that when the construction cost increases,the transportation cost and carbon emission cost will decrease,which indicates that the dry port-seaport logistics network established under the BRI can reduce the cost of logistics transportation and environmental pollution.
In the traffic assignment problem for predicting traffic flow patterns in a transportation network, it is important to account for route overlap and non-identical perception variance in route choice analysis. In this ...
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In the traffic assignment problem for predicting traffic flow patterns in a transportation network, it is important to account for route overlap and non-identical perception variance in route choice analysis. In this study, we establish a novel route choice model, named the paired combinatorial weibit (PCW) model, to capture the route overlap and route-specific perception variance. The PCW model retains a closed-form probability solution, which allows the development of an equivalent mathematical programming (MP) formulation for the PCW-based stochastic user equilibrium (PCW-SUE) model. Specifically, we propose two equivalent MP formulations for modeling the fixed demand (FD) and elastic demand (ED), named PCW-SUE-FD and PCW-SUEED, respectively. The PCW-SUE-ED model can address the abovementioned two issues in route choice for the FD scheme, but also can consider the effect level-of-service (LOS) in travel choice for the ED scheme. The equivalency and uniqueness of the PCW-SUE-FD and PCW-SUE-ED models are rigorously proved. In addition, a path-based partial linearization algorithm combined with a self-regulated averaging line search strategy is developed to solve the two SUE models. Numerical results are presented to illustrate the features of the PCW-SUE-FD and PCW-SUE-ED models and applicability of the solution algorithm to a real transportation network.
Maintenance planning is one of the main challenges of the management of production systems. Thanks to recent technological innovations and the development of sensors, it is possible to construct degradation models of ...
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Maintenance planning is one of the main challenges of the management of production systems. Thanks to recent technological innovations and the development of sensors, it is possible to construct degradation models of equipment condition, thus providing an assessment of the equipment health modeled by a health index indicator. In this work, we present an original tactical maintenance planning problem involving a Health Index indicator on the components of the equipment. Within this framework, maintenance can be seen as a form of delayed production. This observation allows us to derive an original lot-sizing based approach for our tactical maintenance planning problem. Aside from the classical cost minimization objective, the problem also involves a resource consumption objective to be minimized. The problem is proven to be strongly NP-hard in the general case, and a bi-objective Mixed Integer Linear Program is proposed. Then, two matheuristics are defined. A degradation matheuristic allowing several degradations of the objective functions and a Pareto-based matheuristic selecting solution of good quality from a restricted pareto front.
Integer programming (IP) is an extension of linear programming (LP) whereby the goal is to determine values for a set of decision variables (some or all of which have integer restrictions) so as to maximize or minimiz...
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The Unmanned Aerial Vehicles (UAVs), commonly known as drones, are significant in the agriculture sphere to automate the work such as: data acquisition, crop spraying among others. This paper proposes a path planning ...
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ISBN:
(数字)9781665499965
ISBN:
(纸本)9781665499965
The Unmanned Aerial Vehicles (UAVs), commonly known as drones, are significant in the agriculture sphere to automate the work such as: data acquisition, crop spraying among others. This paper proposes a path planning solution for a team of UAVs that is required to whiten a greenhouse's roof, this problem having both social-economic impact, as well as scientific-technical impact. First, the space around the roof is partitioned into cells based on a 3D cell decomposition technique, labeling the cells including the surface of the roof as regions of interest (ROIs). Based on this representation, a Petri net (PN) model captures the motion of drones, while their trajectories are returned by a Mixed Integer Linear programming (MILP) problem which optimizes the energy consumption. An adaptable strategy is used such that the MILP problem considers only the available UAVs with enough energy to reach the ROIs. The algorithm is implemented in MATLAB and the simulation results are captured in a video link, evaluating the impact of the size of the team and the precision used for mapping the environment over the running time.
The study of a better use of hydrogen in refineries is essential due to its increasing use in hydrotreating fractions obtained from petroleum. Since several factors affect this process, it is essential not only that t...
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The study of a better use of hydrogen in refineries is essential due to its increasing use in hydrotreating fractions obtained from petroleum. Since several factors affect this process, it is essential not only that the hydrogen network must be able to operate feasibly in various conditions but also accomplish it with minimum costs. In this work, a systematic approach is proposed considering a multi-scenario optimization problem formulation for the network design coupled with the flexibility evaluation of the proposed design to verify the flexibility and identify critical scenarios that are used to update the previous set of scenarios for the design problem. As a result, it is obtained a cost-efficient flexible design. The proposed approach can be used for new designs or for the retrofit case. For the design a superstructure based MILP and MINLP multi-scenario models were developed and completely described, to optimize hydrogen networks through uncertainties in hydrogen consumption in consumer units. The flexibility index problem formulated for hydrogen networks is presented. All the optimization models were implemented in the modeling system GAMS. The initialization strategy consist of using the network obtained from linear optimization as a starting point for nonlinear optimization. In addition, it was also used the proposed technique of virtual compressors, able to reduce the cost of capital even further. Two case studies were used to validate the proposed approach. A case study from the literature was used and also a second case using real data of a Brazilian refinery. Compared to the initially proposed network, the model through optimization achieved flexible design with a reduction of more than 13.8% (example 1) and 16% (example 2) in the operating cost. For both cases, the procedure could find a cost-efficient flexible design that can be coupled with the refinery production planning for the whole process economy. (c) 2021 Institution of Chemical Engineers. Pu
Waste thermal energy recovery with thermoelectric generators has been widely studied as a method to make systems that produce hot exhaust gases, such as aircrafts, ground vehicles and factories, more sustainable. In t...
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Waste thermal energy recovery with thermoelectric generators has been widely studied as a method to make systems that produce hot exhaust gases, such as aircrafts, ground vehicles and factories, more sustainable. In this type of applications, the mismatch in hot and cold side temperatures of thermoelectric modules (TEMs) creates a mismatch in the electrical output. For each situation, there is a certain electrical interconnection between the modules that gives the maximum global power output. Three optimization models to find what is the best way of connecting the TEMs without a trial-and-error process, as usually done in previous literature, based on mathematical programming are proposed: single branch of series-connected TEMs, multiple parallelconnected branches of series-connected TEMs, and multiple groups of independent series-connected TEMs. The main novel contributions of this paper are: (i) a mathematical optimization approach that provides how to connect the thermoelectric modules one by one, (ii) the application of the above-mentioned method in a common case study: an automotive thermoelectric generator, (iii) information about how the optimal connection between modules changes if the heat source changes its operation (iv) a method for selecting a fixed optimal connection even when the heat source operation changes, e.g. different operation modes in a thermal engine, based on introducing weighting parameters in the optimization mathematical model. The optimization approach followed here is novel and has not been applied before to thermoelectric generators.
The benefits of automation in human-operated assembly lines are well known. Despite the rapid progress made in the field, complete automation is not always possible. Often robots cannot replace workers' flexibilit...
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The benefits of automation in human-operated assembly lines are well known. Despite the rapid progress made in the field, complete automation is not always possible. Often robots cannot replace workers' flexibility, and sometimes there is no economically viable option for automation. A combined production system with both manual and automated parts could be the best configuration in such circumstances. Even with partial automation the number of workers in the line could be decreased, and workers' safety and health conditions could be dramatically improved. In this paper, MILP models are suggested to compare the total workload of workers when different numbers of robots are applied in an assembly line with partial automation and the minimum possible number of workers. The proposed MILP model is implemented in the AIMNIS modelling environment and solved using CPLEX. The presented models can help evaluate the impact of adding robots to the line on total workers' workload and may assist decision makers in finding the best possible line configuration. Copyright (C) 2022 The Authors.
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