2022
Ahmady-Moghaddam, Nima; Osterholz, Daniel; Clemen, Thomas
Implementation and Application of a Base Model for Agent-Based Modelling Situated in Hamburg, Germany Inproceedings
In: Simulation in den Umwelt- und Geowissenschaften (Workshop Müncheberg 2021), pp. 99–110, GI (Gesellschaft für Informatik) Shaker Verlag, 2022, ISBN: 978-3-8440-8551-8.
Abstract | BibTeX | Tags: agent-based model, decision support systems, MARS, model development, multimodal travel, sohh, urban planning
@inproceedings{Ahm2022a,
title = {Implementation and Application of a Base Model for Agent-Based Modelling Situated in Hamburg, Germany},
author = {Ahmady-Moghaddam, Nima and Osterholz, Daniel and Clemen, Thomas},
isbn = {978-3-8440-8551-8},
year = {2022},
date = {2022-04-29},
booktitle = {Simulation in den Umwelt- und Geowissenschaften (Workshop Müncheberg 2021)},
volume = {1},
issue = {1},
pages = {99--110},
publisher = {Shaker Verlag},
organization = {GI (Gesellschaft für Informatik)},
abstract = {Agent-based models (ABMs) that are set in a specific geographic region tend to be rooted in similar geodata to define the setting and, by extension, tend to have a similar representation in their
environments. At the core, their agent types also tend to be similar. For example, ABMs that model a city’s traffic flow are likely populated by representations of vehicles and people as agents, just as ABMs that model the spread of infectious diseases might be populated by people and pathogens as agents. If these data and components that are common to ABMs with similar settings are gathered and implemented in a generalized fashion, the resulting model can potentially be used to develop a wide range of more domain-specific scenarios in the given setting. We refer to such a model as a base model. In this article, we describe the conception and implementation of a base model for the city of Hamburg, Germany. The process of data collection and preparation is outlined, and the portability of the approach to other geographic settings is highlighted. The base model's applicability is demonstrated by using it to create two simulation scenarios, each focused on a different domain and research question. Simulation data are analysed to address the research questions and showcase the base model’s potential. While data availability is one of the main limiting factors of a base model's efficacy, we find that a well-maintained and up-to-date base model can be a valuable tool for modellers and stakeholders, especially when required to make informed decisions under time constraints.},
keywords = {agent-based model, decision support systems, MARS, model development, multimodal travel, sohh, urban planning},
pubstate = {published},
tppubtype = {inproceedings}
}
Agent-based models (ABMs) that are set in a specific geographic region tend to be rooted in similar geodata to define the setting and, by extension, tend to have a similar representation in their
environments. At the core, their agent types also tend to be similar. For example, ABMs that model a city’s traffic flow are likely populated by representations of vehicles and people as agents, just as ABMs that model the spread of infectious diseases might be populated by people and pathogens as agents. If these data and components that are common to ABMs with similar settings are gathered and implemented in a generalized fashion, the resulting model can potentially be used to develop a wide range of more domain-specific scenarios in the given setting. We refer to such a model as a base model. In this article, we describe the conception and implementation of a base model for the city of Hamburg, Germany. The process of data collection and preparation is outlined, and the portability of the approach to other geographic settings is highlighted. The base model's applicability is demonstrated by using it to create two simulation scenarios, each focused on a different domain and research question. Simulation data are analysed to address the research questions and showcase the base model’s potential. While data availability is one of the main limiting factors of a base model's efficacy, we find that a well-maintained and up-to-date base model can be a valuable tool for modellers and stakeholders, especially when required to make informed decisions under time constraints.
environments. At the core, their agent types also tend to be similar. For example, ABMs that model a city’s traffic flow are likely populated by representations of vehicles and people as agents, just as ABMs that model the spread of infectious diseases might be populated by people and pathogens as agents. If these data and components that are common to ABMs with similar settings are gathered and implemented in a generalized fashion, the resulting model can potentially be used to develop a wide range of more domain-specific scenarios in the given setting. We refer to such a model as a base model. In this article, we describe the conception and implementation of a base model for the city of Hamburg, Germany. The process of data collection and preparation is outlined, and the portability of the approach to other geographic settings is highlighted. The base model's applicability is demonstrated by using it to create two simulation scenarios, each focused on a different domain and research question. Simulation data are analysed to address the research questions and showcase the base model’s potential. While data availability is one of the main limiting factors of a base model's efficacy, we find that a well-maintained and up-to-date base model can be a valuable tool for modellers and stakeholders, especially when required to make informed decisions under time constraints.
Lenfers, U. A.; Ahmady-Moghaddam, N.; Glake, D.; Ocker, F.; Weyl, J.; Clemen, T.
Modeling the Future Tree Distribution in a South African Savanna Ecosystem: An Agent-Based Model Approach Journal Article
In: Land, vol. 11, iss. 5, no. 619, 2022, ISSN: 2073-445X.
Abstract | Links | BibTeX | Tags: adaptive behavior, agent-based model, Bushbuckridge, decision support systems, firewood collection, Kruger, MARS, model development
@article{Lenfers2022a,
title = {Modeling the Future Tree Distribution in a South African Savanna Ecosystem: An Agent-Based Model Approach},
author = {Lenfers, U.A. and Ahmady-Moghaddam, N. and Glake, D. and Ocker, F. and Weyl, J. and Clemen, T.},
url = {https://www.mdpi.com/2073-445X/11/5/619},
doi = {10.3390/land11050619},
issn = {2073-445X},
year = {2022},
date = {2022-04-22},
urldate = {2022-04-22},
journal = {Land},
volume = {11},
number = {619},
issue = {5},
abstract = {Understanding the dynamics of tree species and their demography is necessary for predicting future developments in savanna ecosystems. In this contribution, elephant-tree and firewood collector-tree interactions are compared using a multiagent model. To investigate these dynamics, we compared three different tree species in two plots. The first plot is located in the protected space of Kruger National Park (KNP), South Africa, and the second plot in the rural areas of the Bushbuckridge Municipality, South Africa. The agent-based modeling approach enabled the modeling of individual trees with characteristics such as species, age class, size, damage class, and life history. A similar level of detail was applied to agents that represent elephants and firewood collectors. Particular attention was paid to modeling purposeful behavior of humans in contrast to more instinct-driven actions of elephants. The authors were able to predict future developments by simulating the time period between 2010 and 2050 with more than 500,000 individual trees. Modeling individual trees for a time span of 40 years might yield more detailed information than a simple woody mass aggregation. The results indicate a significant trend toward more and thinner trees together with a notable reduction in mature trees, while the total aboveground biomass appears to stay more or less constant. Furthermore, the KNP scenarios show an increase in young Combretum apiculatum, which may correspond to bush encroachment.},
keywords = {adaptive behavior, agent-based model, Bushbuckridge, decision support systems, firewood collection, Kruger, MARS, model development},
pubstate = {published},
tppubtype = {article}
}
Understanding the dynamics of tree species and their demography is necessary for predicting future developments in savanna ecosystems. In this contribution, elephant-tree and firewood collector-tree interactions are compared using a multiagent model. To investigate these dynamics, we compared three different tree species in two plots. The first plot is located in the protected space of Kruger National Park (KNP), South Africa, and the second plot in the rural areas of the Bushbuckridge Municipality, South Africa. The agent-based modeling approach enabled the modeling of individual trees with characteristics such as species, age class, size, damage class, and life history. A similar level of detail was applied to agents that represent elephants and firewood collectors. Particular attention was paid to modeling purposeful behavior of humans in contrast to more instinct-driven actions of elephants. The authors were able to predict future developments by simulating the time period between 2010 and 2050 with more than 500,000 individual trees. Modeling individual trees for a time span of 40 years might yield more detailed information than a simple woody mass aggregation. The results indicate a significant trend toward more and thinner trees together with a notable reduction in mature trees, while the total aboveground biomass appears to stay more or less constant. Furthermore, the KNP scenarios show an increase in young Combretum apiculatum, which may correspond to bush encroachment.
2021
Lenfers, Ulfia Annette; Ahmady-Moghaddam, Nima; Glake, Daniel; Ocker, Florian; Ströbele, Jonathan; Clemen, Thomas
Incorporating Multi-Modal Travel Planning into an Agent-Based Model: A Case Study at the Train Station Kellinghusenstraße in Hamburg Journal Article
In: Land 2021, vol. 11, no. 10, 2021, ISSN: 2073-445X.
Abstract | Links | BibTeX | Tags: adaptive behavior, agent-based model, decision support systems, multimodal travel, sohh, urban planning
@article{Lenfers2021b,
title = {Incorporating Multi-Modal Travel Planning into an Agent-Based Model: A Case Study at the Train Station Kellinghusenstraße in Hamburg},
author = {Ulfia Annette Lenfers and Nima Ahmady-Moghaddam and Daniel Glake and Florian Ocker and Jonathan Ströbele and Thomas Clemen},
editor = {Simon Elias Bibri},
url = {https://www.mdpi.com/2073-445X/10/11/1179/htm},
doi = {10.3390/land10111179},
issn = {2073-445X},
year = {2021},
date = {2021-11-03},
journal = {Land 2021},
volume = {11},
number = {10},
abstract = {Models can provide valuable decision support in the ongoing effort to create a sustainable and effective modality mix in urban settings. Modern transportation infrastructures must meaningfully combine public transport with other mobility initiatives such as shared and on-demand systems. The increase of options and possibilities in multi-modal travel implies an increase in complexity when planning and implementing such an infrastructure. Multi-agent systems are well-suited for addressing questions that require an understanding of movement patterns and decision processes at the individual level. Such models should feature intelligent software agents with flexible internal logic and accurately represent the core functionalities of new modalities. We present a model in which agents can choose between owned modalities, station-based bike sharing modalities, and free-floating car sharing modalities as they exit the public transportation system and seek to finish their personal multi-modal trip. Agents move on a multi-modal road network where dynamic constraints in route planning are evaluated based on an agent’s query. Modality switch points (MSPs) along the route indicate the locations at which an agent can switch from one modality to the next (e.g., a bike rental station to return a used rental bike and continue on foot). The technical implementation of MSPs within the road network was a central focus in this work. To test their efficacy in a controlled experimental setting, agents optimized only the travel time of their multi-modal routes. However, the functionalities of the model enable the implementation of different optimization criteria (e.g., financial considerations or climate neutrality) and unique agent preferences as well. Our findings show that the implemented MSPs enable agents to switch between modalities at any time, allowing for the kind of versatile, individual, and spontaneous travel that is common in modern multi-modal settings. },
keywords = {adaptive behavior, agent-based model, decision support systems, multimodal travel, sohh, urban planning},
pubstate = {published},
tppubtype = {article}
}
Models can provide valuable decision support in the ongoing effort to create a sustainable and effective modality mix in urban settings. Modern transportation infrastructures must meaningfully combine public transport with other mobility initiatives such as shared and on-demand systems. The increase of options and possibilities in multi-modal travel implies an increase in complexity when planning and implementing such an infrastructure. Multi-agent systems are well-suited for addressing questions that require an understanding of movement patterns and decision processes at the individual level. Such models should feature intelligent software agents with flexible internal logic and accurately represent the core functionalities of new modalities. We present a model in which agents can choose between owned modalities, station-based bike sharing modalities, and free-floating car sharing modalities as they exit the public transportation system and seek to finish their personal multi-modal trip. Agents move on a multi-modal road network where dynamic constraints in route planning are evaluated based on an agent’s query. Modality switch points (MSPs) along the route indicate the locations at which an agent can switch from one modality to the next (e.g., a bike rental station to return a used rental bike and continue on foot). The technical implementation of MSPs within the road network was a central focus in this work. To test their efficacy in a controlled experimental setting, agents optimized only the travel time of their multi-modal routes. However, the functionalities of the model enable the implementation of different optimization criteria (e.g., financial considerations or climate neutrality) and unique agent preferences as well. Our findings show that the implemented MSPs enable agents to switch between modalities at any time, allowing for the kind of versatile, individual, and spontaneous travel that is common in modern multi-modal settings.
Nima Ahmady-Moghaddam Ulfia A. Lenfers, Daniel Glake; Clemen, Thomas
Improving Model Predictions—Integration of Real-Time Sensor Data into a Running Simulation of an Agent-Based Model Journal Article
In: Sustainability, vol. 13, no. 13, 2021.
Abstract | Links | BibTeX | Tags: agent-based model, decision support systems, IoT sensors, MARS, model development, multimodal travel, real-time data, simulation correction, smart cities, sohh, urban planning
@article{Lenfers2021,
title = {Improving Model Predictions—Integration of Real-Time Sensor Data into a Running Simulation of an Agent-Based Model},
author = {Ulfia A. Lenfers, Nima Ahmady-Moghaddam, Daniel Glake, Florian Ocker, Daniel Osterholz, Jonathan Ströbele and Thomas Clemen},
editor = {Philippe J. Giabbanelli and Arika Ligmann-Zielinska},
url = {https://doi.org/10.3390/su13137000},
doi = {10.3390/su13137000},
year = {2021},
date = {2021-06-22},
journal = {Sustainability},
volume = {13},
number = {13},
abstract = {The current trend towards living in big cities contributes to an increased demand for efficient and sustainable space and resource allocation in urban environments. This leads to enormous pressure for resource minimization in city planning. One pillar of efficient city management is a smart intermodal traffic system. Planning and organizing the various kinds of modes of transport in a complex and dynamically adaptive system such as a city is inherently challenging. By deliberately simplifying reality, models can help decision-makers shape the traffic systems of tomorrow. Meanwhile, Smart City initiatives are investing in sensors to observe and manage many kinds of urban resources, making up a part of the Internet of Things (IoT) that produces massive amounts of data relevant for urban planning and monitoring. We use these new data sources of smart cities by integrating real-time data of IoT sensors in an ongoing simulation. In this sense, the model is a digital twin of its real-world counterpart, being augmented with real-world data. To our knowledge, this is a novel instance of real-time correction during simulation of an agent-based model. The process of creating a valid mapping between model components and real-world objects posed several challenges and offered valuable insights, particularly when studying the interaction between humans and their environment. As a proof-of-concept for our implementation, we designed a showcase with bike rental stations in Hamburg-Harburg, a southern district of Hamburg, Germany. Our objective was to investigate the concept of real-time data correction in agent-based modeling, which we consider to hold great potential for improving the predictive capabilities of models. In particular, we hope that the chosen proof-of-concept informs the ongoing politically supported trends in mobility—away from individual and private transport and towards—in Hamburg.},
keywords = {agent-based model, decision support systems, IoT sensors, MARS, model development, multimodal travel, real-time data, simulation correction, smart cities, sohh, urban planning},
pubstate = {published},
tppubtype = {article}
}
The current trend towards living in big cities contributes to an increased demand for efficient and sustainable space and resource allocation in urban environments. This leads to enormous pressure for resource minimization in city planning. One pillar of efficient city management is a smart intermodal traffic system. Planning and organizing the various kinds of modes of transport in a complex and dynamically adaptive system such as a city is inherently challenging. By deliberately simplifying reality, models can help decision-makers shape the traffic systems of tomorrow. Meanwhile, Smart City initiatives are investing in sensors to observe and manage many kinds of urban resources, making up a part of the Internet of Things (IoT) that produces massive amounts of data relevant for urban planning and monitoring. We use these new data sources of smart cities by integrating real-time data of IoT sensors in an ongoing simulation. In this sense, the model is a digital twin of its real-world counterpart, being augmented with real-world data. To our knowledge, this is a novel instance of real-time correction during simulation of an agent-based model. The process of creating a valid mapping between model components and real-world objects posed several challenges and offered valuable insights, particularly when studying the interaction between humans and their environment. As a proof-of-concept for our implementation, we designed a showcase with bike rental stations in Hamburg-Harburg, a southern district of Hamburg, Germany. Our objective was to investigate the concept of real-time data correction in agent-based modeling, which we consider to hold great potential for improving the predictive capabilities of models. In particular, we hope that the chosen proof-of-concept informs the ongoing politically supported trends in mobility—away from individual and private transport and towards—in Hamburg.