Simulation-Transactions of the Society for Modeling and Simulation International最新文献_第5页

A methodological approach for modeling the spread of disease using geographical discrete-event spatial models 使用地理离散事件空间模型对疾病传播进行建模的方法学方法

IF 1.6 4区工程技术 Q4 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Simulation-Transactions of the Society for Modeling and Simulation International

Pub Date : 2023-02-14 DOI: 10.1177/00375497231152458

G. Davidson, Aidan Fahlman, Eric Mereu, Cristina Ruiz Martin, G. Wainer, P. Dobias, Mark Rempel

The study of infectious disease models has become increasingly important during the COVID-19 pandemic. The forecasting of disease spread using mathematical models has become a common practice by public health authorities, assisting in creating policies to combat the spread of the virus. Common approaches to the modeling of infectious diseases include compartmental differential equations and cellular automata, both of which do not describe the spatial dynamics of disease spread over unique geographical regions. We introduce a new methodology for modeling disease spread within a pandemic using geographical models. We demonstrate how geography-based Cell-Discrete-Event Systems Specification (DEVS) and the Cadmium JavaScript Object Notation (JSON) library can be used to develop geographical cellular models. We exemplify the use of these methodologies by developing different versions of a compartmental model that considers geographical-level transmission dynamics (e.g. movement restriction or population disobedience to public health guidelines), the effect of asymptomatic population, and vaccination stages with a varying immunity rate. Our approach provides an easily adaptable framework that allows rapid prototyping and modifications. In addition, it offers deterministic predictions for any number of regions simulated simultaneously and can be easily adapted to unique geographical areas. While the baseline model has been calibrated using real data from Ontario, we can update and/or add different infection profiles as soon as new information about the spread of the disease become available.

在COVID-19大流行期间，传染病模型的研究变得越来越重要。利用数学模型预测疾病传播已成为公共卫生当局的一种常见做法，有助于制定对抗病毒传播的政策。传染病建模的常用方法包括区隔微分方程和元胞自动机，这两种方法都没有描述疾病在独特地理区域传播的空间动态。我们介绍了一种使用地理模型在大流行中模拟疾病传播的新方法。我们演示了如何使用基于地理的单元-离散事件系统规范(DEVS)和镉JavaScript对象表示法(JSON)库来开发地理单元模型。我们通过开发不同版本的分区模型来举例说明这些方法的使用，该模型考虑了地理层面的传播动态(例如，运动限制或人群对公共卫生指南的不服从)，无症状人群的影响以及具有不同免疫率的疫苗接种阶段。我们的方法提供了一个易于适应的框架，允许快速原型和修改。此外，它为同时模拟的任何数量的区域提供确定性预测，并且可以很容易地适应独特的地理区域。虽然基线模型是使用安大略省的真实数据进行校准的，但一旦获得有关该疾病传播的新信息，我们就可以更新和/或添加不同的感染概况。

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引用次数: 1

A simulation approach for COVID-19 pandemic assessment based on vaccine logistics, SARS-CoV-2 variants, and spread rate. 基于疫苗物流、SARS-CoV-2变异和传播率的COVID-19大流行评估模拟方法

IF 1.6 4区工程技术 Q4 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Simulation-Transactions of the Society for Modeling and Simulation International

Pub Date : 2023-02-01 DOI: 10.1177/00375497221120018

Burak Erkayman, Ferhat Ak, Sadrettin Çodur

Despite advances in clinical care for the coronavirus (COVID-19) pandemic, population-wide interventions are vital to effectively manage the pandemic due to its rapid spread and the emergence of different variants. One of the most important interventions to control the spread of the disease is vaccination. In this study, an extended Susceptible-Infected Healed (SIR) model based on System Dynamics was designed, considering the factors affecting the rate of spread of the COVID-19 pandemic. The model predicts how long it will take to reach 70% herd immunity based on the number of vaccines administered. The designed simulation model is modeled in AnyLogic 8.7.2 program. The model was performed for three different vaccine supply scenarios and for Turkey with ~83 million population. The results show that, with a monthly supply of 15 million vaccines, social immunity reached the target value of 70% in 161 days, while this number was 117 days for 30 million vaccines and 98 days for 40 million vaccines.

尽管冠状病毒(COVID-19)大流行的临床护理取得了进展，但由于其迅速传播和不同变体的出现，全民干预对于有效管理大流行至关重要。控制疾病传播的最重要干预措施之一是接种疫苗。考虑影响新冠肺炎疫情传播速度的因素，设计了基于系统动力学的易感感染愈合(susceptibility - infected heal, SIR)扩展模型。该模型根据接种疫苗的数量预测达到70%的群体免疫力需要多长时间。设计的仿真模型在AnyLogic 8.7.2程序中建模。该模型是针对三种不同的疫苗供应方案和约8300万人口的土耳其进行的。结果表明，在每月供应1500万支疫苗的情况下，社会免疫力在161天内达到70%的目标值，而3000万支疫苗需要117天，4000万支疫苗需要98天。

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引用次数: 0

Modeling and simulation of a multistage heat recovery steam generator 多级热回收蒸汽发生器的建模与仿真

IF 1.6 4区工程技术 Q4 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Simulation-Transactions of the Society for Modeling and Simulation International

Pub Date : 2023-02-01 DOI: 10.1177/00375497221130098

Jonathan McConnell, Tuhin Das, Andres Caesar, P. Veeravalli

As the share of renewable energy increases in modern power grids, their inherent intermittency compels existing thermal power plants to become more agile and flexible in their operation. To achieve such flexibility, understanding the transient behavior of thermal power plants is key. In this regard, physics-based dynamic models are useful tools. They help in predicting performance and in exploring various operating conditions in a risk-free, cost-effective manner. To this end, this paper presents a multi-stage Heat Recovery Steam Generator (HRSG) model. Fast simulations are demonstrated for this three pressure-stage system with interconnected thermodynamic and mass transfer phenomena. The HRSG’s multi-physics behavior is captured through mathematically modeled and numerically simulated phase change, fluid dynamics, and thermal coupling. Heat exchange elements such as economizers and superheaters are modeled by directly solving the Unsteady Flow Energy Equation (UFEE). The phase change dynamics of the boiler are modeled using a multi-mode switching mechanism, where each mode is characterized by boiling/evaporation/condensation and heating/cooling phenomena. A judicious combination of spatially discretized or lumped and dynamic or quasi-static models is used to achieve reasonably accurate transient response while lowering the computational burden. In collaboration with Siemens Energy Inc., steady-state prediction capability and transient pressure behavior are validated with plant startup data from an operational HRSG.

随着可再生能源在现代电网中所占份额的增加，其固有的间歇性迫使现有火电厂在运行中变得更加敏捷和灵活。要实现这种灵活性，了解火电厂的瞬态行为是关键。在这方面，基于物理的动态模型是有用的工具。它们有助于以无风险、低成本的方式预测性能和探索各种操作条件。为此，本文提出了多级热回收蒸汽发生器(HRSG)模型。对具有相互关联的热力学和传质现象的三压力级系统进行了快速模拟。通过数学建模和数值模拟的相变、流体动力学和热耦合，可以捕捉到HRSG的多物理场行为。采用直接求解非定常流能方程(UFEE)的方法对省煤器和过热器等换热元件进行建模。采用多模式切换机制对锅炉的相变动力学进行建模，其中每种模式都具有沸腾/蒸发/冷凝和加热/冷却现象的特征。将空间离散化或集总化模型与动态或准静态模型合理地结合起来，可以在降低计算量的同时获得较为精确的瞬态响应。通过与西门子能源公司的合作，通过运行HRSG的工厂启动数据验证了稳态预测能力和瞬态压力行为。

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引用次数: 1

Investigating the effects of various control measures on economy and spread of COVID-19 in Turkey: a system dynamics approach. 调查各种控制措施对土耳其经济和COVID-19传播的影响:系统动力学方法。

IF 1.6 4区工程技术 Q4 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Simulation-Transactions of the Society for Modeling and Simulation International

Pub Date : 2023-02-01 DOI: 10.1177/00375497221116641

Muzaffer Alım, Saadettin Erhan Kesen

The coronavirus disease 2019 (COVID-19) which began in Wuhan in December 2019 has permeated all over the world in such a short time and was declared as a pandemic by World Health Organization (WHO). The pandemic that is erupting all of a sudden attracts the researchers to examine the spread and effects of the disease as well as the possible treatments and vaccine developments. In addition to the analytical models, such as compartmental modeling, Markov decision process, and so on, simulation and system dynamics (SD) are also widely applied in this field. In this study, we adopt the compartmental modeling stages to build an SD approach for the spread of the disease. A dynamic control measure decision support system (DSS) that varies depending on the number of daily cases is incorporated to the model. Furthermore, the economic loss in the gross domestic product (GDP) and workforce due to hospital stay and death caused by the COVID-19 are also investigated. The model is tested with various numerical parameters and the results are presented. The results on the spread of the disease and the associated economic loss provide meaningful insights into when control measures need to be imposed at which level. We also provide some policy insights, including some alternative policies, such as increasing awareness of people and vaccination in addition to control measures. The results reveal that the total number of cases and deaths is approximately 37% higher in the absence of dynamic DSS. However, everything comes at a price and applying such control measures brings about an increase in the economic loss about 47%.

2019年12月在武汉开始的新型冠状病毒病(COVID-19)在如此短的时间内蔓延到世界各地，并被世界卫生组织(WHO)宣布为大流行。突然爆发的大流行吸引了研究人员来研究这种疾病的传播和影响，以及可能的治疗方法和疫苗的发展。除了分析模型，如分区建模、马尔可夫决策过程等，仿真和系统动力学(SD)也被广泛应用于这一领域。在本研究中，我们采用分区建模阶段来建立疾病传播的SD方法。在模型中加入了一个动态控制措施决策支持系统(DSS)，该系统随日常案例数量的变化而变化。此外，还调查了因COVID-19造成的住院和死亡而导致的国内生产总值(GDP)和劳动力的经济损失。用不同的数值参数对模型进行了试验，并给出了试验结果。关于疾病传播和相关经济损失的结果为何时需要在哪个级别实施控制措施提供了有意义的见解。我们还提供了一些政策见解，包括一些替代政策，例如除了控制措施外，还要提高人们的认识和接种疫苗。结果显示，在没有动态DSS的情况下，病例总数和死亡人数大约高出37%。然而，一切都是有代价的，采取这种控制措施会使经济损失增加约47%。

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引用次数: 1

Computational fluid dynamics simulation of airborne COVID transmission in urban bus with different HVAC configurations 不同HVAC配置下城市客车空气传播的计算流体动力学仿真

IF 1.6 4区工程技术 Q4 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Simulation-Transactions of the Society for Modeling and Simulation International

Pub Date : 2023-01-28 DOI: 10.1177/00375497221151168

D. Ramajo, S. Corzo

The HVAC systems in closed buses promote high particle spread. Lagrangian particle tracking simulations were carried out to evaluate airborne COVID transmission through droplets emitted by sneezing while Eulerian simulations were performed to account for the spread of aerosols emitted by breathing. The position of passengers as well as the effect of three HVAC configurations were evaluated. On one hand, it was concluded that large droplets can travel more than 3 m without being significantly affected by the inflow conditions, but small droplets are easily dispersed by the airflow, and many of them are captured by the HVAC systems. On the other hand, the HVAC systems quickly spreads aerosols along the whole of the bus, increasing the average risk for all passengers, but sensibly reducing the high local risks observed under motionless inflow conditions. The transmission risk was calculated by applying the Wells-Riley model, concluding that the transmission risk for a 20-min trip could remain below 0.5% if HVAC configurations with many inlet/outlet vents are implemented, and the passengers remain in silence and wear face masks.

封闭客车的暖通空调系统促进了高颗粒的扩散。采用拉格朗日粒子跟踪模拟来评估通过打喷嚏释放的飞沫传播的空气传播，采用欧拉模拟来解释呼吸释放的气溶胶的传播。评估了乘客的位置以及三种HVAC配置的效果。一方面，大液滴可以在不受入流条件影响的情况下移动3 m以上，但小液滴容易被气流分散，其中许多液滴被暖通空调系统捕获。另一方面，暖通空调系统在整个巴士上迅速扩散气溶胶，增加了所有乘客的平均风险，但明显降低了在静止流入条件下观察到的高局部风险。通过应用Wells-Riley模型计算传播风险，得出的结论是，如果采用具有多个进/出气孔的HVAC配置，并且乘客保持安静并戴口罩，那么20分钟行程的传播风险可以保持在0.5%以下。

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引用次数: 1

Low-latency GNSS multipath simulation and building wall detection in urban environments 城市环境下低延迟GNSS多径仿真与建筑墙体检测

IF 1.6 4区工程技术 Q4 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Simulation-Transactions of the Society for Modeling and Simulation International

Pub Date : 2023-01-20 DOI: 10.1177/00375497221145601

Marcus O'Connor, T. Kersten, C. Skupin, Fabian Ruwisch, Le Ren, T. Wübbena, S. Schön

Precise navigation for fully autonomous driving—especially in dense urban areas—requires periodic precise position estimates. Global Navigation Satellite System (GNSS) technology has the potential to provide absolute positioning accuracy at a centimeter level. However, buildings in urban environments cause signal distortions and signal reflections—the so-called multipath—which are the most challenging parts in the GNSS error budget. Hence, we developed a scalable real-time multipath simulator for mitigating potential multipath receptions. The simulator uses three-dimensional (3D) building information, satellite, and user positions. The key drivers of latency are the calculation of reflection, diffraction, and line-of-sight, as well as the response time of the 3D building model database. The memory manager of the graphic processing units (GPUs) in combination with a dedicated load balancer enables fast and efficient multipath analysis. Selected case studies demonstrate the simulator’s potential to significantly improve the position accuracy of the processing engine. The use of the multipath simulator reduces the error in 61% of the error measurements in a stress test scenario to less than half of the non-multipath processing. The scalability of the simulator is demonstrated by combining the multipath simulator with a traffic simulator. Furthermore, we present a novel methodology for the detection of walls using GNSS signals to better account for incomplete or erroneous 3D building information in GNSS signal processing.

完全自动驾驶的精确导航——尤其是在人口密集的城市地区——需要定期进行精确的位置估计。全球导航卫星系统(GNSS)技术有可能提供厘米级的绝对定位精度。然而，城市环境中的建筑物会导致信号失真和信号反射，即所谓的多路径，这是GNSS误差预算中最具挑战性的部分。因此，我们开发了一个可扩展的实时多路径模拟器，以减轻潜在的多路径接收。模拟器使用三维(3D)建筑信息、卫星和用户位置。延迟的关键驱动因素是反射、衍射和视线的计算，以及3D建筑模型数据库的响应时间。图形处理单元(gpu)的内存管理器与专用负载平衡器相结合，可实现快速高效的多路径分析。选定的案例研究表明，模拟器的潜力，以显着提高处理引擎的位置精度。多路径模拟器的使用将压力测试场景中61%的误差测量中的误差减少到不到非多路径处理的一半。通过将多路径模拟器与流量模拟器相结合，验证了该模拟器的可扩展性。此外，我们提出了一种使用GNSS信号检测墙壁的新方法，以更好地解释GNSS信号处理中不完整或错误的3D建筑信息。

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引用次数: 0

A formal GSPN model of a virtual doctor dialogue system 虚拟医生对话系统的形式化GSPN模型

IF 1.6 4区工程技术 Q4 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Simulation-Transactions of the Society for Modeling and Simulation International

Pub Date : 2023-01-18 DOI: 10.1177/00375497221147919

N. Bourbakis, S. Mallios

This paper presents a formal generalized stochastic Petri net (GSPN)–based modeling of a virtual doctor (VDr) dialogue system. The interaction model between the VDr dialogue system and the human patient is a modified version of the Wickens model. The purpose of this model is to provide a better understanding of the interaction between the VDr dialogue system and the patient, as well as the integration of other components in the system, such as the patient’s medical history and emotions. Initially, the formal definition of the GSPN model of the VDr dialogue system is presented by incorporating the token color concept, which is a feature of Color GSPNs. Then, the GSPN formal modeling is described. Note that, the GSPN model presented here is at the simulation level and not a product. Furthermore, some examples are provided with the intention of facilitating the understanding of the token color utilization and the different GSPN markings.

本文提出了一种基于形式化广义随机Petri网(GSPN)的虚拟医生对话系统建模方法。VDr对话系统与人类患者之间的交互模型是对Wickens模型的改进。该模型的目的是更好地理解VDr对话系统与患者之间的交互，以及系统中其他组件的集成，例如患者的病史和情绪。首先，通过引入颜色GSPN的特征令牌颜色概念，给出了VDr对话系统GSPN模型的形式化定义。然后，对GSPN的形式化建模进行了描述。请注意，这里提供的GSPN模型是在模拟级别，而不是产品。此外，为了便于理解令牌颜色的使用和不同的GSPN标记，还提供了一些示例。

引用次数: 1

DP in ice environments—development of a dynamic positioning in ice validation platform (DPIVP) 冰环境下的DP——动态定位冰验证平台的开发

IF 1.6 4区工程技术 Q4 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Simulation-Transactions of the Society for Modeling and Simulation International

Pub Date : 2023-01-12 DOI: 10.1177/00375497221141463

Jason Mills, Mohammed Islam, Wayne Pearson, Bob Gash

This paper presents the development of a dynamic positioning in ice validation platform (DPIVP) which is part of a larger research project aimed at developing dynamic positioning (DP) system technologies for ice-rich environments. One outcome is simulation software to aid research in this area. The DPIVP software was designed to realistically simulate the dynamics of ice-structure interactions for real-time applications and to validate components common to DP in ice simulations. The software consists of many components which the DPIVP ties together as a unified system. All components have well-defined interfaces. Many of them are also distributed, allowing execution on separate computers and/or CPUs which helps ensure real-time operation. These two characteristics also decreases coupling and encourages a more modular design with the benefit of easily substituting alternative component implementations without reprogramming the DPIVP. Alternate implementations are useful for conducting research in specific DP in ice areas without substantially changing the system, such as alternative ice force models, DP control algorithms, vessel models, 3D and 2D visualization, environment models, and data acquisition systems. The integrated system was tested and evaluated using unit testing, integration testing, and system testing. The completed system was also validated using test cases that match physical model tests; the results compared favorably. Although the software has some limitations, for example, validated ice-force models being limited to two vessels, and thus lacks the generality we wish, the end result is a working prototype that satisfies the research requirements and provides an architecture and framework for future development.

本文介绍了冰下动态定位验证平台(DPIVP)的开发，这是一个旨在开发富冰环境动态定位(DP)系统技术的大型研究项目的一部分。一个成果是模拟软件，以帮助在这一领域的研究。DPIVP软件旨在为实时应用逼真地模拟冰-结构相互作用的动态，并验证DP在冰模拟中的常见组件。该软件由许多组件组成，DPIVP将这些组件连接在一起作为一个统一的系统。所有组件都有定义良好的接口。它们中的许多也是分布式的，允许在不同的计算机和/或cpu上执行，这有助于确保实时操作。这两个特性还减少了耦合，并鼓励更模块化的设计，其好处是无需重新编程DPIVP即可轻松替换可选组件实现。替代实现对于在冰区进行特定DP研究非常有用，而无需实质性改变系统，例如替代冰力模型，DP控制算法，船舶模型，3D和2D可视化，环境模型和数据采集系统。使用单元测试、集成测试和系统测试对集成系统进行测试和评估。完成的系统还使用与物理模型测试相匹配的测试用例进行了验证;结果比较有利。虽然该软件有一些局限性，例如，验证的冰力模型仅限于两艘船，因此缺乏我们希望的通用性，但最终结果是一个满足研究要求的工作原型，并为未来的发展提供了一个架构和框架。

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引用次数: 2

Stair/escalator/elevator selection behavior of passengers in subway stations based on the fuzzy logic theory 基于模糊逻辑理论的地铁车站乘客楼梯/自动扶梯/电梯选择行为

IF 1.6 4区工程技术 Q4 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Simulation-Transactions of the Society for Modeling and Simulation International

Pub Date : 2023-01-12 DOI: 10.1177/00375497221145645

Rui Zhang, Xiaoxia Yang, Meiqi Zhou, Yongxing Li, Xiaoli Yang

The behavior of stair/escalator/elevator selection of passengers at the subway platform could directly affect the travel efficiency and even the service level of the station. This paper proposes a stair/escalator/elevator selection model of passengers at the subway platform, where the cellular automata model is used to simulate passenger movement, and the fuzzy logic theory is used to describe selection behavior. The distance to the stair/escalator/elevator and the density of passengers in front of the facility are selected as the main influence factors. The rationality and effectiveness of the selection model are verified by comparing the field data with simulation results of passengers choosing different stairs/escalators/elevators. The relationship between passenger quantity, passenger speed, escalator quantity, escalator location, and the traffic rate is analyzed based on simulation results, which can provide a theoretical reference for the facility layout optimization at the platform floor of the subway station.

乘客在地铁站台的楼梯/自动扶梯/电梯选择行为直接影响到车站的出行效率甚至服务水平。本文提出了一种地铁站台乘客楼梯/自动扶梯/电梯选择模型，该模型采用元胞自动机模型模拟乘客运动，并采用模糊逻辑理论描述乘客选择行为。选择到楼梯/自动扶梯/电梯的距离和设施前的乘客密度作为主要影响因素。将现场数据与乘客选择不同楼梯/自动扶梯/电梯的仿真结果进行对比，验证了选择模型的合理性和有效性。基于仿真结果，分析了地铁站台客流量、乘客速度、扶梯数量、扶梯位置与通行率之间的关系，为地铁站台层设施布局优化提供理论参考。

引用次数: 2

Proposal of a module-driven architecture for building simulation models devoted to container terminals: dilemmas in applying generic, flexible, and modular principles 模块驱动的集装箱码头仿真模型构建体系结构的建议:通用、灵活和模块化原则的应用困境

IF 1.6 4区工程技术 Q4 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Simulation-Transactions of the Society for Modeling and Simulation International

Pub Date : 2023-01-12 DOI: 10.1177/00375497221144646

Mohamed Nezar Abourraja, N. Kringos, S. Meijer

Container terminals are complex systems where containerized cargo undergoes a set of processing and handling operations to be delivered to their outgoing modes. A pool of decision support methods and simulation models has been developed to assist planners and managers in making decisions about daily operations. Nevertheless, most are designed for a particular terminal and not generic types. Indeed, a generic model serves as a conceptual factory to create specific models which greatly reduces the time and efforts of development; however, building such a model is no mean feat. To this aim, the paper on hand discusses the complexity of applying genericity, flexibility, and modularity in system modeling and proposes a generic architecture to build modular and flexible simulation models for container terminals. This architecture is split into a set of smaller, manageable, well-connected, and generic modules that facilitate the creation of highly parametrized specific models. An illustrative example of the architecture usage is presented in a case study, the new container terminal of Stockholm, and the resulting models were validated by subject matter experts. Finally, to prove its efficiency, a numerical study fed with real data is conducted to investigate the handling capacity of the studied system under different handling and flow scenarios. The obtained results show that the terminal handling capacity can be increased by around 50% if three to four more straddle carriers are added to the existing fleet.

集装箱码头是一个复杂的系统，在这里，集装箱货物要经过一系列的加工和处理操作，才能送到他们的出站模式。已经开发了一套决策支持方法和模拟模型，以协助规划人员和管理人员对日常业务作出决策。然而，大多数都是为特定的终端而不是通用类型设计的。实际上，通用模型可以作为一个概念工厂来创建特定的模型，这大大减少了开发的时间和精力;然而，建立这样一个模型绝非易事。为此，本文讨论了在系统建模中应用通用性、灵活性和模块化的复杂性，并提出了一种通用的体系结构来构建模块化和柔性的集装箱码头仿真模型。该体系结构被分成一组较小的、可管理的、连接良好的通用模块，这些模块有助于创建高度参数化的特定模型。在一个案例研究中，提出了一个架构使用的说明性示例，即斯德哥尔摩的新集装箱码头，并由主题专家验证了所得到的模型。最后，为验证该方法的有效性，利用实际数据对研究系统在不同处理和流量情况下的处理能力进行了数值研究。结果表明，如果在现有船队中再增加3至4艘跨界运输船，码头的处理能力可增加约50%。

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引用次数: 1