A large-scale traffic simulator with microscopic model requires trip generation for millions of vehicles. To achieve a realistic result, the trip generation should provide a variety of trips between pairs of locations...
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ISBN:
(纸本)9781479939503;9781479920778
A large-scale traffic simulator with microscopic model requires trip generation for millions of vehicles. To achieve a realistic result, the trip generation should provide a variety of trips between pairs of locations from Origin-Destination (OD) table reflecting the choices of drivers. Shortest paths take long time to generate and often differ from the choices of drivers. We propose a simple and fast tree-based algorithm in this paper. Our algorithm mixes shortest path trees starting from some location nodes in each subarea of the OD table as preprocessing and then generates trips by probabilistically traversing the mixed shortest path trees. Experiments reveal that the tree-based algorithm runs much faster than the naive one. We also confirm that, under certain conditions on the granularity of the OD table, the results of simulation using trips generated by our algorithm do not differ much from traffic conditions observed in the real world.
Many insurers pay independent agencies a contingent commission based on the agency's performance. The insurer must accrue funds during the year to recognize the expected contingent commission payout in the financi...
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ISBN:
(纸本)9781479939503;9781479920778
Many insurers pay independent agencies a contingent commission based on the agency's performance. The insurer must accrue funds during the year to recognize the expected contingent commission payout in the financial statements. Westfield Insurance wanted to reduce their accrual forecasting error from 20 percent to less than five percent. We built a Monte Carlo simulation to simulate each Westfield agency's performance. We clustered agencies into representative groups as a proxy for generating correlated random variables and then designed an experiment to shift statistical distributions of agency key performance indicators. The results of the simulation were then used to derive a formula for forecasting expected contingent commissions based on overall company results. The approach, results, and areas for further research are discussed.
Serious infections due to antibiotic-resistant bacteria are pervasive, and of particular concern within hospital units due to frequent interaction among health-care workers and patients. Such nosocomial infections are...
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ISBN:
(纸本)9781479939503;9781479920778
Serious infections due to antibiotic-resistant bacteria are pervasive, and of particular concern within hospital units due to frequent interaction among health-care workers and patients. Such nosocomial infections are difficult to eliminate because of inconsistent disinfection procedures and frequent interactions among infected persons, and because ill-chosen antibiotic treatment strategies can lead to a growth of resistant bacterial strains. Clinical studies to address these concerns have several issues, but chief among them are the effects on the patients involved. Realistic simulation models offer an attractive alternative. This paper presents a hybrid simulation model of antibiotic resistant infections in a hospital ward, combining agentbased simulation to model the inter-host interactions of patients and health-care workers with a detailed differential equations and probabilistic model of intra-host bacterial and antibiotic dynamics. Initial results to benchmark the model demonstrate realistic behavior and suggest promising extensions to achieve a highly-complex yet accurate mechanism for testing antibiotic strategies.
In this paper a simulation model is developed for evaluation of different berthing scenarios in Shahid Rajaee Container Terminal. Model is trying to handle Berth Allocation and Quay-Crane Assignment Problems simultane...
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ISBN:
(纸本)9781479939503;9781479920778
In this paper a simulation model is developed for evaluation of different berthing scenarios in Shahid Rajaee Container Terminal. Model is trying to handle Berth Allocation and Quay-Crane Assignment Problems simultaneously for more efficient solutions. Validity of developed model is examined by sensitivity analysis on model parameters and after that three berthing scenarios has been put to test in model and obtained results suggests that "Length Based Allocation" berthing scenario can reduce the turnaround time for vessels and also increase completed jobs by berth at a fixed time period.
ConductingVerification andValidation (V&V) of modeling and simulation (M&S) requires systematic and structured application of differentV&V techniques throughout the M& S life cycle. Whether an existing...
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ISBN:
(纸本)9781479939503;9781479920778
ConductingVerification andValidation (V&V) of modeling and simulation (M&S) requires systematic and structured application of differentV&V techniques throughout the M& S life cycle. Whether an existing technique is appropriate to a particularV&V activity depends not only on the characteristics of the technique but also on the situation where it will be applied. Although there already exit several guidance documents describing aVariety ofV&V techniques and their application potential, accessible findings or experiences on the effective selection of suitableV&V techniques for a given M&S context are still lacking. This paper presents: 1.) a characterization approach to developing aV&V techniques catalog that packages the available techniques together with the information about their application conditions;and 2.) a planning and tailoring strategy for project-specific selection of the appropriateV&V techniques from the established catalog according to the goals and characteristics of a simulation study.
Gaming simulation in the railway sector often uses the same conceptual model as in computer simulation, and enables operators to interact with this model during a simulation run. Therefore, gaming simulation validatio...
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ISBN:
(纸本)9781479939503;9781479920778
Gaming simulation in the railway sector often uses the same conceptual model as in computer simulation, and enables operators to interact with this model during a simulation run. Therefore, gaming simulation validation poses different challenges. This paper aims to answer the question to what extent gaming simulation can be used as an experimental research setting, due to its loosely demarcated experimental features. Focusing on validity issues, we study five cases in which the Dutch railway sector used gaming simulation to test innovations in a controlled environment. The results show that in addition to traditional external validity issues, human game players inherently open up this controlled environment, bringing in many confounding variables. By signaling what the specific validity threats are, this paper strives to improve gaming simulation for testing innovations that tackle social and technical elements of a system.
Haulage cost typically accounts for around 30% of the total cost of mass earthmoving projects. The temporary road network is a major factor influencing haulage cost and production efficiency. The simulation of earthmo...
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ISBN:
(纸本)9781479939503;9781479920778
Haulage cost typically accounts for around 30% of the total cost of mass earthmoving projects. The temporary road network is a major factor influencing haulage cost and production efficiency. The simulation of earthmoving operations considering temporary road networks, not only facilitates the site formation design but also leads to realistic, cost-effective construction plans. Utilizing the Floyd-Warshall algorithm and linear programming, this study formulates the temporary road network problem and sheds light on the potential benefits of selecting routes and directions for handling earthmoving jobs. An optimization approach for temporary road networks is further proposed. It reduces the total cost of the project and shortens its duration. simulation models were used to prove the effectiveness and feasibility of optimization.
The overhead-crane scheduling problem with spatial constraints has attracted extensive attention and lots of approaches are introduced to solve the problem. As we all know, in the manufacturing plant the crane schedul...
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ISBN:
(纸本)9781479939503;9781479920778
The overhead-crane scheduling problem with spatial constraints has attracted extensive attention and lots of approaches are introduced to solve the problem. As we all know, in the manufacturing plant the crane scheduling is one part of the production scheduling. However, most of approaches concern the crane scheduling in isolation. In this paper, we include the crane scheduling problem into the production scheduling environment and combine them together to obtain an integrated schedule. A simulation-based optimization solves this integrated scheduling problem. A genetic algorithm is introduced to determine the allocation of machines and cranes. A simulation model referring to a queuing network is used to evaluate the crane and machine allocation results and provides the fitness value for the genetic algorithm. The sequences of operations (processing and transporting) on each machine and each crane are determined by using the dispatching rule LPT. A heuristic deals with crane collision events.
This work introduces an application of simulation-optimization techniques to the emerging field of green internet computing. The paper discusses the relevance of considering environmental factors in modern computing a...
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ISBN:
(纸本)9781479939503;9781479920778
This work introduces an application of simulation-optimization techniques to the emerging field of green internet computing. The paper discusses the relevance of considering environmental factors in modern computing and then describes how simulation can be combined with scheduling metaheuristics in order to reduce the expected time needed to complete a set of tasks in a server under the realistic assumption of stochastic processing times. This, in turn, allows for a reduction in average energy consumption, which makes the computing facility more efficient from an environmental perspective. Some experiments have been carried out in order to illustrate these potential savings.
Planning the loading operations on a vessel in a container terminal is a very time-consuming activity. On one hand, the placement of the containers within the vessel must satisfy various constraints;on the other, resh...
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ISBN:
(纸本)9781479939503;9781479920778
Planning the loading operations on a vessel in a container terminal is a very time-consuming activity. On one hand, the placement of the containers within the vessel must satisfy various constraints;on the other, reshuffles, i.e., unfruitful movements performed on the yard to retrieve a target container when it is not located on top of a stack, should be avoided. To support the work of terminal planners, we propose a simulation model that returns an accurate estimate of the number of reshuffles required with respect to a given loading sequence plan and a given yard configuration. The simulation model accounts for great details on operations under stochastic conditions. The estimates returned do not deteriorate as the dimension and complexity of the problem grow. Numerical experiments carried out for a real container terminal show how the model may easily support the planners in their daily job
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