Research

34 pages, 8212 KiB

Open AccessArticle

Contingencies of Violent Radicalization: The Terror Contagion Simulation

by Timothy Clancy, Bland Addison, Oleg Pavlov and Khalid Saeed

Systems 2021, 9(4), 90; https://0-doi-org.brum.beds.ac.uk/10.3390/systems9040090 - 20 Dec 2021

Cited by 3 | Viewed by 4493

This paper builds confidence in the terror contagion hypothesis that violent radicalization leading to predatory mass violence operates as a system. Within this system, the contingent values of key root causes create channels within which violent ideologies and terrorism emerge. We built a [...] Read more.

This paper builds confidence in the terror contagion hypothesis that violent radicalization leading to predatory mass violence operates as a system. Within this system, the contingent values of key root causes create channels within which violent ideologies and terrorism emerge. We built a system dynamics simulation model capable of replicating historical reference modes and sophisticated enough to test the contingent values of these propositions. Of 16 propositions, we identified six root-cause propositions that must simultaneously exist, act in concert and explain the dynamics of their interaction which generate a terror contagion. Other propositions can strengthen or weaken an existing contagion but not eliminate it. We use an experiment to demonstrate how changing the contingent values of these propositions creates downward channels. This experiment helps reconcile the swarm vs. fishermen debate over the true root causes of violent radicalization. Within these channels, the contingent values can favor swarm or fishermen manifestations. The simulation and experimentation results enable the future development of the terror contagion hypothesis, provide a testing environment for research on violent radicalization, and provide a pathway to policy development in the combating of terrorism that arises from violent radicalization. Full article

(This article belongs to the Special Issue System Dynamics: Insights and Policy Innovation)

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22 pages, 3361 KiB

Open AccessArticle

Latent Errors and Visible Earned Value: How the Evolutionary Model Integrates Earned Value Metrics with Project System Dynamics

by John M. Nevison and Karim J. Chichakly

Systems 2021, 9(4), 88; https://0-doi-org.brum.beds.ac.uk/10.3390/systems9040088 - 16 Dec 2021

Cited by 1 | Viewed by 2318

Abstract

A project model is presented that weaves together ideas from earned value project management and systems dynamics. It is able to adjust to increasingly unhealthy actual project behaviors in ways that preserve the signature pattern of the staffing histograms observed in the real [...] Read more.

A project model is presented that weaves together ideas from earned value project management and systems dynamics. It is able to adjust to increasingly unhealthy actual project behaviors in ways that preserve the signature pattern of the staffing histograms observed in the real world and provide a tool for managers to correct projects that are not meeting the plan. Starting from the planned staffing histogram and the project performance baseline, the model captures the delay and cost of experience dilution, includes the unplanned-for effort that is revealed in the typical pattern of the Cost Performance Index, assesses progress using the actual cost to date and the earned value to date, and adjusts staffing, scope, or both, to complete the project on schedule. A new method of approximating work remaining, called project-to-date, is shown to track the planned staffing histogram better than the commonly used fraction-complete method. Full article

(This article belongs to the Special Issue System Dynamics: Insights and Policy Innovation)

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22 pages, 5425 KiB

Open AccessArticle

Identifying Climate Adjacency for Enhancing Climate Action Using Systems Thinking and Modelling

by Kabir Sharma and Mihir Mathur

Systems 2021, 9(4), 83; https://0-doi-org.brum.beds.ac.uk/10.3390/systems9040083 - 16 Nov 2021

Cited by 2 | Viewed by 4268

Abstract

This paper presents findings from a process aimed at identifying the climate linkages of non-climate focused environment and development projects in India. Findings from four case studies based on workshops using participatory systems thinking are summarized. These climate adjacencies are documented as systems [...] Read more.

This paper presents findings from a process aimed at identifying the climate linkages of non-climate focused environment and development projects in India. Findings from four case studies based on workshops using participatory systems thinking are summarized. These climate adjacencies are documented as systems stories using the tools of systems thinking—behavior over time graphs and causal loop diagrams. These place-based stories highlight how the environment and development projects have linkages with climate change mitigation and adaptation. An attempt has been made to convert one of the systems stories into a computable simulation model using system dynamics modelling. A small concept model has been created thus and used to perform simulation runs. Four scenarios have been generated and the results discussed. Our learning from converting feedback maps into stock-flow models is presented. The insights generated from interpreting the feedback maps and simulation results are also presented. These insights are then compared and the benefits of simulation evaluated. The paper highlights the need to document climate linkages of non-climate-focused development projects and the benefit of converting systems stories into simulation models for developing operational insights. The important role such methods can play in developing capacities for enhancing climate action is also discussed. Full article

(This article belongs to the Special Issue System Dynamics: Insights and Policy Innovation)

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19 pages, 5928 KiB

Open AccessArticle

Behavioral Implications in COVID-19 Spread and Vaccinations

by Karim Chichakly

Systems 2021, 9(4), 72; https://0-doi-org.brum.beds.ac.uk/10.3390/systems9040072 - 14 Oct 2021

Cited by 4 | Viewed by 3038

Abstract

COVID-19 vaccinations have been administered quickly in the USA. However, a surprisingly large number of Americans are unwilling to get vaccinated. Without enough people getting vaccinated, the pandemic will not end. The longer the pandemic persists, the more opportunities exist for more virulent [...] Read more.

COVID-19 vaccinations have been administered quickly in the USA. However, a surprisingly large number of Americans are unwilling to get vaccinated. Without enough people getting vaccinated, the pandemic will not end. The longer the pandemic persists, the more opportunities exist for more virulent strains to emerge. This model looks at the effects of people’s behavior in containing and ending the COVID-19 pandemic in the USA. Human behavior adds several feedback loops to the standard SEIR model. Comparisons are made between cases with and without behavior loops, with reduced adherence to the recommended or mandated masks and social distancing, with and without the vaccine, and the effects of an early mask mandate termination. The results suggest human behavior must be accounted for in epidemiology models and that removing masks before enough vaccine are administered not only puts those vaccinated at risk, but allows the disease to readily spread again. Full article

(This article belongs to the Special Issue System Dynamics: Insights and Policy Innovation)

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18 pages, 5055 KiB

Open AccessArticle

Transforming a Liability into an Asset: A System Dynamics Model for Free-Ranging Dog Population Management

by Urmila Basu Mallick, Marja H. Bakermans and Khalid Saeed

Systems 2021, 9(3), 56; https://0-doi-org.brum.beds.ac.uk/10.3390/systems9030056 - 29 Jul 2021

Cited by 1 | Viewed by 3083

Abstract

Using Indian free-ranging dogs (FRD) as a case study, we propose a novel intervention of social integration alongside previously proposed methods for dealing with FRD populations. Our study subsumes population dynamics, funding avenues, and innovative strategies to maintain FRD welfare and provide societal [...] Read more.

Using Indian free-ranging dogs (FRD) as a case study, we propose a novel intervention of social integration alongside previously proposed methods for dealing with FRD populations. Our study subsumes population dynamics, funding avenues, and innovative strategies to maintain FRD welfare and provide societal benefits. We develop a comprehensive system dynamics model, featuring identifiable parameters customizable for any management context and imperative for successfully planning a widescale FRD population intervention. We examine policy resistance and simulate conventional interventions alongside the proposed social integration effort to compare monetary and social rewards, as well as costs and unintended consequences. For challenging socioeconomic ecological contexts, policy resistance is best overcome by shifting priority strategically between social integration and conventional techniques. The results suggest that social integration can financially support a long-term FRD intervention, while transforming a “pest” population into a resource for animal-assisted health interventions, law enforcement, and conservation efforts. Full article

(This article belongs to the Special Issue System Dynamics: Insights and Policy Innovation)

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19 pages, 805 KiB

Open AccessArticle

Integrated Policy Solutions for Water Scarcity in Agricultural Communities of the American Southwest

by Saeed P. Langarudi, Connie M. Maxwell and Alexander G. Fernald

Systems 2021, 9(2), 26; https://0-doi-org.brum.beds.ac.uk/10.3390/systems9020026 - 17 Apr 2021

Cited by 2 | Viewed by 2902

Abstract

The conventional approach of policy interventions in water management that focus on the portions of the system that directly relate to water often lead to unintended consequences that potentially exacerbate water scarcity issues and present challenges to the future viability of many rural [...] Read more.

The conventional approach of policy interventions in water management that focus on the portions of the system that directly relate to water often lead to unintended consequences that potentially exacerbate water scarcity issues and present challenges to the future viability of many rural agricultural communities. This paper deploys a system dynamics model to illustrate how expanding the policy space of hydrology models to include socioeconomic feedbacks could address these challenges. In this regard, policies that can potentially mitigate general water scarcity in a region of the American Southwest in southern New Mexico are examined. We selected and tested policies with the potential to diminish water scarcity without compromising the system’s economic performance. These policies included supporting choices that reduce or limit the expansion of water-intensive crops, promoting workforce participation, encouraging investment in capital, and regulating land use change processes. The simulation results, after the proposed boundary expansion, unveiled intervention options not commonly exercised by water decision-makers, bolstering the argument that integrated approaches to water research that include socioeconomic feedbacks are crucial for the study of agricultural community resilience. Full article

(This article belongs to the Special Issue System Dynamics: Insights and Policy Innovation)

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11 pages, 2690 KiB

Open AccessArticle

Cancer as a System Dysfunction

by Khalid Saeed, Elizabeth F. Ryder and Amity L. Manning

Systems 2021, 9(1), 14; https://0-doi-org.brum.beds.ac.uk/10.3390/systems9010014 - 09 Feb 2021

Cited by 3 | Viewed by 2816

Abstract

In this paper, we describe a system dynamics model that views cancer as a dysfunction of the cellular system rather than as an ailment of cells. Our experiments with the model replicate the propagation of the ailment and the impacts of the treatments. [...] Read more.

In this paper, we describe a system dynamics model that views cancer as a dysfunction of the cellular system rather than as an ailment of cells. Our experiments with the model replicate the propagation of the ailment and the impacts of the treatments. It presents a concept that deviates from the pervasive view of cancer as a cell malfunction that has led to treatments aiming to destroy the rogue cells. It points to more holistic treatment options aiming at reforming cell interaction so the system can contain the growth of cancer cells. Further research is needed to explore the details for such options. Full article

(This article belongs to the Special Issue System Dynamics: Insights and Policy Innovation)

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33 pages, 8508 KiB

Open AccessArticle

Simulating a Watershed-Scale Strategy to Mitigate Drought, Flooding, and Sediment Transport in Drylands

by Connie M. Maxwell, Saeed P. Langarudi and Alexander G. Fernald

Systems 2019, 7(4), 53; https://0-doi-org.brum.beds.ac.uk/10.3390/systems7040053 - 28 Nov 2019

Cited by 7 | Viewed by 5437

Abstract

Drylands today are facing a landscape-scale water storage problem. Throughout the increasingly arid Southwest of the United States, vegetation loss in upland watersheds is leading to floods that scour soils and transport sediment that clogs downstream riparian areas and agricultural infrastructure. The resulting [...] Read more.

Drylands today are facing a landscape-scale water storage problem. Throughout the increasingly arid Southwest of the United States, vegetation loss in upland watersheds is leading to floods that scour soils and transport sediment that clogs downstream riparian areas and agricultural infrastructure. The resulting higher flow energies and diminished capacity to infiltrate flood flows are depleting soil water storage across the landscape, negatively impacting agriculture and ecosystems. Land and water managers face challenges to reverse the trends due to the complex interacting social and biogeophysical root causes. Presented here is an integrative system dynamics model that simulates innovative and transformative management scenarios. These scenarios include the natural and hydro-social processes and feedback dynamics critical for achieving long-term mitigation of droughts, flooding, and sediment transport. This model is a component of the Flood Flow Connectivity to the Landscape framework, which integrates spatial and hydrologic process models. Scenarios of support and collaboration for land management innovations are simulated to connect flood flow to the floodplains throughout the watershed to replenish soil storage and shallow groundwater aquifers across regional scales. The results reveal the management policy levers and trade-off balances critical for restoring management and water storage capacity to the system for long-term resilience. Full article

(This article belongs to the Special Issue System Dynamics: Insights and Policy Innovation)

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25 pages, 5722 KiB

Open AccessFeature PaperArticle

A System Dynamics Model Examining Alternative Wildfire Response Policies

by Matthew P. Thompson, Yu Wei, Christopher J. Dunn and Christopher D. O’Connor

Systems 2019, 7(4), 49; https://0-doi-org.brum.beds.ac.uk/10.3390/systems7040049 - 04 Oct 2019

Cited by 3 | Viewed by 5810

Abstract

In this paper, we develop a systems dynamics model of a coupled human and natural fire-prone system to evaluate changes in wildfire response policy. A primary motivation is exploring the implications of expanding the pace and scale of using wildfires as a forest [...] Read more.

In this paper, we develop a systems dynamics model of a coupled human and natural fire-prone system to evaluate changes in wildfire response policy. A primary motivation is exploring the implications of expanding the pace and scale of using wildfires as a forest restoration tool. We implement a model of a forested system composed of multiple successional classes, each with different structural characteristics and propensities for burning at high severity. We then simulate a range of alternative wildfire response policies, which are defined as the combination of a target burn rate (or inversely, the mean fire return interval) and a predefined transition period to reach the target return interval. We quantify time paths of forest successional stage distributions, burn severity, and ecological departure, and use departure thresholds to calculate how long it would take various policies to restore forest conditions. Furthermore, we explore policy resistance where excessive rates of high burn severity in the policy transition period lead to a reversion to fire exclusion policies. Establishing higher burn rate targets shifted vegetation structural and successional classes towards reference conditions and suggests that it may be possible to expand the application of wildfires as a restoration tool. The results also suggest that managers may be best served by adopting strategies that define aggressive burn rate targets but by implementing policy changes slowly over time. Full article

(This article belongs to the Special Issue System Dynamics: Insights and Policy Innovation)

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582 KiB

Open AccessArticle

An Examination of the Influence of Household Financial Decision Making on the US Housing Market Crisis

by Purba Mukerji, Khalid Saeed and Neal Tan

Systems 2015, 3(4), 378-398; https://0-doi-org.brum.beds.ac.uk/10.3390/systems3040378 - 08 Dec 2015

Cited by 1 | Viewed by 5956

Abstract

This paper investigates the impact of what the extant literature has come to view as some of the major causes of the 2007 US housing market crisis. In particular we investigate the hypothesized effect of, lax financial regulations, the “savings glut” that is [...] Read more.

This paper investigates the impact of what the extant literature has come to view as some of the major causes of the 2007 US housing market crisis. In particular we investigate the hypothesized effect of, lax financial regulations, the “savings glut” that is invested in the US from abroad, government support for increased home ownership, rising homeowners’ equity due to the real-estate boom, expansionary monetary policy, and bankruptcy reform. We examine how these hypothesized causes, working through household and institutional level decision-making, based on information availability and incentives, influenced the outcomes in the market for homes. Using a system dynamics model of household finance, we overlay the hypothesized causes chronologically to extrapolate their real-world simultaneous impact and test the hypothesis that they could have together led to the crisis, by simulating and checking against observed data. We find that with the exception of lax financial regulations, each cause by itself provides only a partial explanation of the crisis. Interestingly, the controversial expansionary monetary policy of the Federal Reserve, blamed by some for fueling the crisis, actually prevents the housing market boom from becoming too large. However on the downside, it discourages household savings and causes the fall in home prices to be deeper, due to weak household finances that result from low savings. We confront our model’s assumptions and outcomes with US economic data. We find our model assumptions are justified and simulation results are strongly supported by the data. Full article

(This article belongs to the Special Issue System Dynamics: Insights and Policy Innovation)

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