Jonathan Sallet (University of Maryland) discussed the nature of and policy challenges posed by ... more Jonathan Sallet (University of Maryland) discussed the nature of and policy challenges posed by next-generation networks. He defined next-generation networks as networks that qualitatively improve on existing networks. Such networks generally offer higher bandwidth and new ...
Understandably and perhaps inevitably, the ever more urgent effort to comprehend the causes of vi... more Understandably and perhaps inevitably, the ever more urgent effort to comprehend the causes of violence in Iraq has so far relied on familiar conceptions. The conflict occurring there is variously described as an insurgency, a civil war, and a manifestation of global terrorism. Standard religious and ethnic categories are used to identify the participants and impute their motives. It is becoming evident, however, that the pattern of violence reflects not only a collision of organized purposes but more fundamentally a profound disintegration of Iraq’s social fabric, a process that exposes innocent victims but also limits the capacity of predators. Violence resulting from the breakdown of legal order does not have the same character as that which occurs between managed opponents. Better understanding of that distinction is likely to be one of the more important lessons to be learned.
A major accomplishment of the World Summit on Sustainable Development in Johannesburg was an incr... more A major accomplishment of the World Summit on Sustainable Development in Johannesburg was an increased focus on implementing sustainable development: words are good, actions are better. This results-oriented focus raises several important questions:
Abstract: An agent-based model conflict between herdsmen in east Africa using the MASON agent-bas... more Abstract: An agent-based model conflict between herdsmen in east Africa using the MASON agent-based simulation environment is presented. Herders struggle to keep their herds fed and watered in a GIS-based, spatially diverse environment with data-driven seasonal cycles. ...
SwePub titelinformation: Global Metropolis : The Role of Cities and Metropolitan Areas in the Glo... more SwePub titelinformation: Global Metropolis : The Role of Cities and Metropolitan Areas in the Global Economy.
This paper examines detailed records from the civil conflict in Guatemala between 1977 and 1986. ... more This paper examines detailed records from the civil conflict in Guatemala between 1977 and 1986. It reveals a number of novel patterns which support the use of complex systems methods for understanding civil violence. It finds a surprising, non-linear relationship between ethnic mix and killing; thereby inviting analysis based on group dynamics. It shows the temporal texture of the conflict to be far from smooth, with a power spectrum that closely resembles that of other, better understood, complex systems. The distribution of incident sizes within the data seems to fall into two distinct sets, one of which, corresponding to "regular " conflict, is Zipf distributed, the other of which includes acts of genocide and is distributed differently. This difference may indicate that that agents of the state were proceeding under different types of orders. These results provide an empirical benchmark for the modeling of civil violence and may have implications for conflict preventi...
Proceedings of the 2017 International Conference of The Computational Social Science Society of the Americas, 2017
This paper summarizes priority challenges for social and behavioral modeling based on a recent st... more This paper summarizes priority challenges for social and behavioral modeling based on a recent study building on a base of prior studies. Our focus is less on describing and hand- wringing about the current state than on identifying what is necessary for moving on. Some of the obstacles reflect inherent challenges: social systems are complex adaptive systems; they often pose "wicked problems;" and even the structure of social systems shows emergent behavior. Other obstacles reflect disciplinary norms and practices, mindsets, and numerous very difficult scientific and methodological challenges. We discuss challenges in six groups: (1) tightening links among theory, modeling, and both empirical and computational experimentation; (2) seeking more general and coherent theories while retaining alternative perspectives and narratives, and while effectively confronting multidimensional uncertainty from the outset; (3) assuring that explanatory models represent science faithfully,...
We use mobile device data to construct empirical interpersonal physical contact networks in the c... more We use mobile device data to construct empirical interpersonal physical contact networks in the city of Portland, Oregon, both before and after social distancing measures were enacted during the COVID-19 pandemic. These networks reveal how social distancing measures and the public’s reaction to the incipient pandemic affected the connectivity patterns within the city. We find that as the pandemic developed there was a substantial decrease in the number of individuals with many contacts. We further study the impact of these different network topologies on the spread of COVID-19 by simulating an SEIR epidemic model over these networks, and find that the reduced connectivity greatly suppressed the epidemic. We then investigate how the epidemic responds when part of the population is vaccinated, and we compare two vaccination distribution strategies, both with and without social distancing. Our main result is that the heavy-tailed degree distribution of the contact networks causes a tar...
Jonathan Sallet (University of Maryland) discussed the nature of and policy challenges posed by ... more Jonathan Sallet (University of Maryland) discussed the nature of and policy challenges posed by next-generation networks. He defined next-generation networks as networks that qualitatively improve on existing networks. Such networks generally offer higher bandwidth and new ...
Understandably and perhaps inevitably, the ever more urgent effort to comprehend the causes of vi... more Understandably and perhaps inevitably, the ever more urgent effort to comprehend the causes of violence in Iraq has so far relied on familiar conceptions. The conflict occurring there is variously described as an insurgency, a civil war, and a manifestation of global terrorism. Standard religious and ethnic categories are used to identify the participants and impute their motives. It is becoming evident, however, that the pattern of violence reflects not only a collision of organized purposes but more fundamentally a profound disintegration of Iraq’s social fabric, a process that exposes innocent victims but also limits the capacity of predators. Violence resulting from the breakdown of legal order does not have the same character as that which occurs between managed opponents. Better understanding of that distinction is likely to be one of the more important lessons to be learned.
A major accomplishment of the World Summit on Sustainable Development in Johannesburg was an incr... more A major accomplishment of the World Summit on Sustainable Development in Johannesburg was an increased focus on implementing sustainable development: words are good, actions are better. This results-oriented focus raises several important questions:
Abstract: An agent-based model conflict between herdsmen in east Africa using the MASON agent-bas... more Abstract: An agent-based model conflict between herdsmen in east Africa using the MASON agent-based simulation environment is presented. Herders struggle to keep their herds fed and watered in a GIS-based, spatially diverse environment with data-driven seasonal cycles. ...
SwePub titelinformation: Global Metropolis : The Role of Cities and Metropolitan Areas in the Glo... more SwePub titelinformation: Global Metropolis : The Role of Cities and Metropolitan Areas in the Global Economy.
This paper examines detailed records from the civil conflict in Guatemala between 1977 and 1986. ... more This paper examines detailed records from the civil conflict in Guatemala between 1977 and 1986. It reveals a number of novel patterns which support the use of complex systems methods for understanding civil violence. It finds a surprising, non-linear relationship between ethnic mix and killing; thereby inviting analysis based on group dynamics. It shows the temporal texture of the conflict to be far from smooth, with a power spectrum that closely resembles that of other, better understood, complex systems. The distribution of incident sizes within the data seems to fall into two distinct sets, one of which, corresponding to "regular " conflict, is Zipf distributed, the other of which includes acts of genocide and is distributed differently. This difference may indicate that that agents of the state were proceeding under different types of orders. These results provide an empirical benchmark for the modeling of civil violence and may have implications for conflict preventi...
Proceedings of the 2017 International Conference of The Computational Social Science Society of the Americas, 2017
This paper summarizes priority challenges for social and behavioral modeling based on a recent st... more This paper summarizes priority challenges for social and behavioral modeling based on a recent study building on a base of prior studies. Our focus is less on describing and hand- wringing about the current state than on identifying what is necessary for moving on. Some of the obstacles reflect inherent challenges: social systems are complex adaptive systems; they often pose "wicked problems;" and even the structure of social systems shows emergent behavior. Other obstacles reflect disciplinary norms and practices, mindsets, and numerous very difficult scientific and methodological challenges. We discuss challenges in six groups: (1) tightening links among theory, modeling, and both empirical and computational experimentation; (2) seeking more general and coherent theories while retaining alternative perspectives and narratives, and while effectively confronting multidimensional uncertainty from the outset; (3) assuring that explanatory models represent science faithfully,...
We use mobile device data to construct empirical interpersonal physical contact networks in the c... more We use mobile device data to construct empirical interpersonal physical contact networks in the city of Portland, Oregon, both before and after social distancing measures were enacted during the COVID-19 pandemic. These networks reveal how social distancing measures and the public’s reaction to the incipient pandemic affected the connectivity patterns within the city. We find that as the pandemic developed there was a substantial decrease in the number of individuals with many contacts. We further study the impact of these different network topologies on the spread of COVID-19 by simulating an SEIR epidemic model over these networks, and find that the reduced connectivity greatly suppressed the epidemic. We then investigate how the epidemic responds when part of the population is vaccinated, and we compare two vaccination distribution strategies, both with and without social distancing. Our main result is that the heavy-tailed degree distribution of the contact networks causes a tar...
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Papers by Timothy Gulden