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Perspectives on Modeling and Simulation of Urban Systems with Multiple Actors and Subsystems
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Health Informatics and Logistics. (Hälsoinformatik och logistik, Health Informatics and Logistics)ORCID iD: 0000-0001-5737-8774
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Cities are the spaces of the interaction between social, physical, political, and economic entities, which makes planning and intervening in such systems difficult. Urban systems are complex adaptive systems in that their behaviours are often the result of the interaction of their components. The growth of urban systems is driven by mass urbanization. Their complexity is the result of interactions between its constituent systems and components.

Simulations and models as tools of exploration of urban systems face many challenges to be useful tools for intervening. Throughout the past decades, the use of simulation models focused on providing tools for managing functions and systems within metropolitan and urban environments. The cognizance of the complexity of these environments and the maturity of complexity science as a field of studying complex systems allow for the application of complexity science methods to study urban systems not only as physical systems but as social systems too.

As learning from simulations and models can occur both at their construction and their use, this thesis focused on model and simulation building, running, and final use. The thesis takes into account two main aspects of urban systems. First, urban systems are often multi-stakeholder, that is systems where multiple stakeholders are intervening at the same time, and sometimes without clear boundaries and agency over sub-parts of the system. Second, urban systems can have a multi-subsystem structure, where each subsystem often have their objectives and affecting the rest of the system in unfamiliar ways.

The thesis investigates through a multicase study, with three case studies, five main themes in simulation modeling that relate to increasing validity and usefulness of models for urban complex systems. Those themes are as follows; (1) the ability of simulation to be tools that capture complexity in ways that are similar to the real target systems, (2) the effects of the inclusion of experts in simulation models construction on the models, (3) the ways quantitative and qualitative ways of modeling can together make simulations and models more useful, (4) the value of simulation modeling to study connections in systems that are multi-system and multi-stakeholder, and (5) the ability to learn from models under the model building journey.

The study cases included are modeling of a city pedestrian network, a metropolitan emergency care provision, and urban mental health dynamics. The case studies provided a diversity of system granularity. The methods used for each of the case studies have also been different in able to study different levels of inclusion of expert knowledge, data, and theoretical models.

Besides its contribution to each of the case studies, with new models and simulation approaches, the thesis contributes to the five themes it investigated. It showed simulation modeling to be able to exhibit multiple elements of complexity. It also showed the ability of expert knowledge to help models become more useful and valid either by increasing their realism or level of representation. This result is achieved by the contextualization of the expert knowledge in the case of pedestrian modeling, and its full exploration in the mental health modeling. Furthermore, the thesis shows ways in which simulation and modeling can find and investigate bridges between urban subsystems. The outcomes suggest that simulation modeling can be a useful tool for exploring different kinds of complexity in urban systems as multi-actor and multi-system systems. Models can mirror the complexity of urban systems in their structure. They can also be ways of exploring non-intuitive behaviors and dynamics. Expert knowledge, in particular, is shown throughout the thesis to be able to help simulations achieve more validity and usefulness.

Abstract [sv]

Städer är platser för samspel mellan sociala, fysiska, politiska och ekonomiska enheter, detta gör planering i dessa system svårt. Urbana system är komplexa adaptiva system i och med att systemens beteende ofta är ett resultat av interaktion mellan deras komponenter. Tillväxten av urbana system drivs av massurbanisering. Deras komplexitet är resultatet av interaktioner mellan dess beståndsdelar och komponenter.

Simuleringar och modeller som verktyg för utforskning av stadssystem står inför många utmaningar för att bli användbara verktyg för att skapa åtgärder. Under de senaste decennierna, var inriktningen för användningen av simuleringsmodeller att tillhandahålla verktyg för att hantera och optimera funktioner och system inom storstads- och stadsmiljöer. Kunskapen om komplexiteten i dessa miljöer och mognaden för komplexitetsvetenskap som ett område för att studera komplexa system möjliggör tillämpning av komplexitetsvetenskapliga metoder för att studera stadssystem inte bara som fysiska system utan också som sociala system.

Eftersom lärande från simuleringar och modeller kan förekomma både vid deras uppbyggnad och deras användning, fokuserade denna avhandling på modell- och simuleringsbyggande, testande och slutanvändning. Avhandlingen tar hänsyn till två huvudaspekter av urbana system. För det första innehåller urbana system ofta flera flerparts-aktörer, det vill säga ett system där flera aktörer samverkar samtidigt, och ibland utan tydliga gränser och instanser för underdelar av systemet. För det andra kan urbana system ha en struktur med flera delsystem, där varje delsystem ofta har sina mål och påverkar resten av systemet på okända sätt.

Avhandlingen undersöker genom en flerfallsstudie, med tre fallstudier, fem huvudteman i simuleringsmodellering som relaterar till ökad validitet och användbarhet av modeller för urban komplexa system. Dessa teman är följande; (1) simuleringens förmåga att vara verktyg som fångar upp komplexitet på sätt som liknar de verkliga målsystemen undersöktes, (2) effekterna av att experter inkluderas i konstruktionen av simuleringsmodeller på modellerna studeras, (3) hur kvantitativa och kvalitativa sätt att modellera tillsammans kan göra simuleringar och modeller mer användbara studeras, (4) värdet av simuleringsmodellering för att studera anslutningar i system som är multisystem och består av flerparts-aktörer, och (5) förmågan att lära av modeller under arbetet med konstruktionen av modellen.

De fallstudier som studerats är en modellering av ett nätverk för gående i staden, en akutvårds nätverk inom en storstad, och dynamisk stads mentalhälsovård. Fallstudierna tillhandahöll en mångfald av bildning. Metoderna som använts för var och en av fallstudierna har också varit olika för att kunna studera olika nivåer av inkludering av expertkunskap, data och teoretiska modeller. Förutom dess bidrag till var och en av fallstudierna, med nya modeller och simuleringsmetoder, bidrar avhandlingen till de fem teman som den undersökte. Avhandlingen visade att simuleringsmodellering kunde visa flera element av komplexitet. Avhandlingen visade också effekten av expertkunskap, vilken var att bidra till att modeller blir mer användbara och tillförlitliga antingen genom att öka deras realism eller representationsnivå. Detta resultat uppnås genom kontextualisering av expertkunskapen (första fallstudien) och dess fullständiga undersökningen i modelleringen av psykisk hälsa. Vidare visar avhandlingen sätt på vilka simulering och modellering kan hitta och undersöka broar mellan urbana delsystem.

Resultaten tyder på att simuleringsmodellering kan vara ett användbart verktyg för att utforska olika typer av komplexitet i urbana system genom att de är flera aktörer och multisystem. Modeller kan spegla komplexiteten i urbana system i deras struktur. De kan också vara sätt att utforska icke-intuitivt beteende och dynamik. Särskilt expertkunskap visas i hela avhandlingen kunna bidra till att simuleringar uppnår högre validitet och användbarhet.

Place, publisher, year, edition, pages
Stockholm Sweden: KTH Royal Institute of Technology, 2019. , p. 57
Series
TRITA-CBH-FOU ; 2019:68
Keywords [en]
Simulation & Modeling, Urban Systems, Expert Knowledge, Complexity Science, Mathematical Modeling, Second Order Effects.
Keywords [sv]
Simulering och modellering, urbana system, expertkunskap, Komplexitetsvetenskap, matematisk modellering, andra graden effekt
National Category
Other Engineering and Technologies not elsewhere specified
Research subject
Technology and Health
Identifiers
URN: urn:nbn:se:kth:diva-264064ISBN: 978-91-7873-399-6 (print)OAI: oai:DiVA.org:kth-264064DiVA, id: diva2:1371983
Public defence
2019-12-18, T2, Hälsovägen 11C, Huddinge, 09:30 (English)
Opponent
Supervisors
Note

QC 2019-11-21

Available from: 2019-11-21 Created: 2019-11-21 Last updated: 2019-11-21Bibliographically approved
List of papers
1. Macroscopic Modelling of Complex Multidirectional Pedestrian Intersections
Open this publication in new window or tab >>Macroscopic Modelling of Complex Multidirectional Pedestrian Intersections
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Pedestrian movements are complex to understand and predict. The study of pedestrian flows is useful to the design and operation of pedestrian spaces. This article describes an approach to macroscopically model flows at multidirectional pedestrian intersec- tions. The proposed model relies on an existing pedestrian bidirectional fundamental diagram in combination with the incremental transfer principles in urban intersections to find flows at the level of pedestrian interfaces and intersections as a function of den- sities and few measurable parameters. The model writes the multidirectional pedestrian flows as a system of equations of dependent unidirectional flows. The final model is used as a cell transmission model, and it exhibits behaviour consistent with the Kine- matic Wave Model. The model allows simulating large pedestrian networks over time, relying on very few measurable parameters.

National Category
Other Mathematics
Identifiers
urn:nbn:se:kth:diva-264060 (URN)
Note

QC 20191122

Submitted to a journal

Available from: 2019-11-21 Created: 2019-11-21 Last updated: 2019-11-22Bibliographically approved
2. A hybrid approach for building models and simulations for smart cities: Expert knowledge and low dimensionality
Open this publication in new window or tab >>A hybrid approach for building models and simulations for smart cities: Expert knowledge and low dimensionality
2017 (English)In: Proceedings of the 2017 Winter Simulation Conference, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1551-1562Conference paper, Published paper (Refereed)
Abstract [en]

In face of high urbanization and increasing mobility, models and simulations are used to find answers for urban planning problems. However, simulations face criticism for over-simplifying complex reality, having models disconnected from the context of their use or excluding policy-makers from the building of models. Smart city approaches did not overcome that reality even if they relied more and more on microscopic models, together with data available through technology. This article describes a hybrid approach combining the expert knowledge on the city and its limits in terms of data, with models having the right dimensionality to provide policy-makers and urban managers with the necessary information for understanding and managing the city. This approach has been applied in Venice, but it describes in more general terms a way of bridging the world of theoretically sound models with their potential use.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Series
Proceedings - Winter Simulation Conference, ISSN 0891-7736
National Category
Other Civil Engineering
Identifiers
urn:nbn:se:kth:diva-225492 (URN)10.1109/WSC.2017.8247896 (DOI)000427768601062 ()2-s2.0-85044536722 (Scopus ID)9781538634288 (ISBN)
Conference
WSC 2017
Funder
EU, FP7, Seventh Framework Programme, FP7-SMARTCITIES-2013 609042
Note

QC 20180406

Available from: 2018-04-06 Created: 2018-04-06 Last updated: 2019-11-26Bibliographically approved
3. Agent-Based Modeling of a Network of Emergency Departments in Urban Environments
Open this publication in new window or tab >>Agent-Based Modeling of a Network of Emergency Departments in Urban Environments
2018 (English)In: The CSCI'18 International Conference on Computational Science and Computational Intelligence / [ed] Hamid R. Arabnia, Leonidas Deligiannidis, Fernando G. Tinetti, and Quoc-Nam Tran, Piscataway, New Jersey, 2018, p. 697-702Conference paper, Published paper (Refereed)
Abstract [en]

Modeling the workload of emergency departments traditionally looks into single hospitals. Today, in a world of high urbanization and increasing levels of exchange of flows of information and patients, it is important to have a systems approach when planning or managing emergency care. This paper presents a low-dimensional Agent-Based Simulation to model the provision of emergency care in a metropolitan environment. The model explores the patient choice of emergency departments and its effects on waiting times. Through the Stockholm use-case, the model is shown to be a good fit against data. The model showed also consistent results when tried with another predictable scenario. 

Place, publisher, year, edition, pages
Piscataway, New Jersey: , 2018
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:kth:diva-264053 (URN)
Conference
5th Annual Conf. on Computational Science & Computational Intelligence (CSCI'18) | Dec 13-15, 2018 | Las Vegas, Nevada, USA
Note

QC 20191122

Available from: 2019-11-21 Created: 2019-11-21 Last updated: 2019-11-22Bibliographically approved
4. A System Approach to Study Waiting Times at Emergency Departments in Metropolitan Environments
Open this publication in new window or tab >>A System Approach to Study Waiting Times at Emergency Departments in Metropolitan Environments
2019 (English)In: Proceedings of the 2019 Winter Simulation Conference / [ed] N. Mustafee, K.-H.G. Bae, S. Lazarova-Molnar, M. Rabe, C. Szabo, P. Haas, and Y.-J. Son, Piscataway, New Jersey, 2019Conference paper, Published paper (Refereed)
Abstract [en]

Providing quality emergency care is one of the biggest challenges faced in healthcare today. This article lays the groundwork for operating and planning emergency care provision in metropolitan environments using a system approach that goes beyond studying each emergency department in isolation. The approach consists of the development of an agent-based simulation using a bottom-up approach modeling patients, doctors, hospitals, and their interactions. The simulation is validated against real historical data of waiting times in the Stockholm region. Through experimentation with the simulation, changing the way patients choose emergency departments in metropolitan areas through the provision of information in real-time is shown to have generally a positive effect on waiting times and the quality of care. The simulation analysis shows that the effects are not uniform over the whole system and its agents.

Place, publisher, year, edition, pages
Piscataway, New Jersey: , 2019
National Category
Other Engineering and Technologies not elsewhere specified
Research subject
Applied and Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-264058 (URN)
Conference
WSC 2019
Note

Upcoming

QC 20191126

Available from: 2019-11-21 Created: 2019-11-21 Last updated: 2019-11-26Bibliographically approved
5. A Simulation Study of the Effect of Information on Waiting Times and Quality of Care in Major Emergency Departments in the Stockholm Region
Open this publication in new window or tab >>A Simulation Study of the Effect of Information on Waiting Times and Quality of Care in Major Emergency Departments in the Stockholm Region
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Emergency departments in metropolitan environments face challenges in providing urban populations with the best services. Stockholm, as one of the fastest-growing metropolitan areas in Europe, is challenged to respond to increasing demand for emergency care. This paper studies, through the use of an agent-based simulation, the effect of information on the waiting times and the quality of care in the largest emergency care departments in the Stockholm region. The analysis of the simulation shows the outcomes of informing groups of patients with the expected time to seeing a doctor on the waiting times and the treatment times at emergency departments. The results show the effects of different information strategies and their second-order effects. The aggregation of the results by hospital, municipality, or level of adherence shows the potential winners and losers of the redistribution of patients resulting from such an information system.

National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:kth:diva-264061 (URN)
Note

QC 20191126

Available from: 2019-11-21 Created: 2019-11-21 Last updated: 2019-11-26Bibliographically approved
6. A System of Systems of Mental Health in Cities: Digging Deep into the Origins of Complexity
Open this publication in new window or tab >>A System of Systems of Mental Health in Cities: Digging Deep into the Origins of Complexity
2019 (English)In: Article in journal (Refereed) Submitted
Abstract [en]

Mental health in urban environments is often treated from a healthcare provision perspective. Research in recent decades showed that mental illness in cities is a result of dysfunctional coordination between different city systems and structures. Given the nature of the city as a system of systems, this work builds participatorily a general system dynamic model of factors that affect mental health in urban and regional environments. Through this method, we investigated the challenges of the application of such methodology to identify important factors, feedback loops, and dependencies between systems to move forward in planning for mental health in cities. The outcome is a general model that showed the importance of factors that vary from individuals, families to communities and feedback loops that span multiple systems such as the city physical infrastructures, social environments, schools, labor market, and healthcare provision.

Keywords
Mental Health, System Dynamics, Participatory Methods, Urban Health
National Category
Health Care Service and Management, Health Policy and Services and Health Economy
Identifiers
urn:nbn:se:kth:diva-243017 (URN)
Note

QC 20190208

Available from: 2019-02-01 Created: 2019-02-01 Last updated: 2019-11-21Bibliographically approved
7. Sensitivity Analysis of policy options for urban mental health using system dynamics and fuzzy cognitive maps
Open this publication in new window or tab >>Sensitivity Analysis of policy options for urban mental health using system dynamics and fuzzy cognitive maps
2019 (English)In: Proceedings of the 2019 Winter Simulation Conference / [ed] N. Mustafee, K.-H.G. Bae, S. Lazarova-Molnar, M. Rabe, C. Szabo, P. Haas, and Y.-J. Son, eds., 2019Conference paper, Published paper (Refereed)
Abstract [en]

Urban mental health challenges call for new ways of designing policies to address the ongoing mental health issues in cities. Policymaking for mental health in cities is extremely difficult due to the complex nature of mental health, the structure of cities, and their multiple subsystems. This paper presents a general system dynamic model of factors affecting mental health and a method to test the sensitivity of the model to policy options using an approach combining system dynamics and fuzzy cognitive maps. The method is developed and tested to evaluate policies built around feedback loops. The approach succeeded in identifying the factors that substantially improve the mental health of the city population for specific contexts. It also suggests the coordination needed between different subsystems to reach these objectives.

National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:kth:diva-264059 (URN)
Conference
WSC 2019
Note

QC 20191126

Available from: 2019-11-21 Created: 2019-11-21 Last updated: 2019-11-26Bibliographically approved

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