Stochastic Modeling of Non-linear Terrorism Dynamics

Author(s):  
Jakub Drmola ◽  
Tomáš Hubík

Abstract Modeling terrorism is both necessary and difficult. While the necessity comes from the all too obvious real-world pressures our society is facing, the difficulty stems from the underlying complexity of the phenomena itself – there are many variables to account for, they are hard to measure, and the relationships between them are confounding. Since modeling terrorism is at its most onerous when it comes to predicting specific attacks, their timing and scale, we opted to work around this using observed probabilistic distribution and integrate power laws into our system dynamics model. After evaluating thousands of simulations runs, this allows us to replicate historical data as well as produce prognostic scenarios, while maintaining what we believe to be authentic behavior. Compromises need to be made, but we believe that this approach can be useful for systems highly dependent on events or parameters which we are unable to predict but whose distributions are known.

Author(s):  
Nayem Rahman ◽  
Mahmud Ullah

Conservation of any living creature is very vital to maintain the balance of ecosystem. Fish is one of the most regularly consumed living creatures, and hence its conservation is essential for sustainable fish population to help maintain a balanced ecosystem. It is possible to keep a sustainable fish population only if a balance between consumption and growth of fish population can be ensured. Developing a model on fish population dynamics is needed to achieve this objective. In this chapter, the authors present a system dynamics model. This model will provide the scientific tools for determining fish population, its growth, and harvesting. The model's sensitivity to changes in key parameters and initial values resulting from the changes in basic scenarios and boundary conditions was tested several times. Model results show that fish birth, growth, stocks, and catch can be controlled timely and effectively in different real-world changing conditions to maintain a sustainable fish population.


Author(s):  
Nasir Bedewi Siraj ◽  
Aminah Robinson Fayek

Traditional risk analysis techniques are ineffective for capturing the dynamic causal interactions and subjective uncertainties involved in assessing risk and opportunity events since they treat risks independently and rely on the availability of sufficient historical data. In this paper, a hybrid fuzzy system dynamics (FSD) model is developed to analyze the impacts of interrelated and interacting risk and opportunity events on work package cost to determine work package and project contingencies using expert judgement and subjective assessment. A fuzzy DEMATEL method is employed to structure and analyze the causal interactions among risk and opportunity events. This paper provides the following contributions: (1) a systematic risk assessment and prioritization procedure; (2) a structured method for defining the dynamic causal relationships among risk and opportunity events and quantifying their impact on work package and project contingencies using FSD; and (3) a method for representing linguistic variables and applying fuzzy arithmetic in FSD.


2014 ◽  
Vol 5 (2) ◽  
pp. 39-53 ◽  
Author(s):  
Nayem Rahman

To visualize or address complex real world problems, eliciting and mapping of a mental model is reasonable approach but it is far from sufficient by itself. In this article we present a system dynamics model. The purpose of the model is to develop a sustainable model for fish population, growth, and harvesting. The model was run through several important tests to determine its sensitivity to changing in key parameters and initial values with different scenarios and boundary conditions. Model results show that fish birth, growth, stocks and catch can be controlled quickly in different real-world changing conditions to maintain a sustainable fish population.


2010 ◽  
Vol 20 (2) ◽  
pp. 59-62
Author(s):  
Patrick Einzinger ◽  
Günther Zauner ◽  
G. Ganjeizadeh-Rouhani

Systems ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 56
Author(s):  
Urmila Basu Mallick ◽  
Marja H. Bakermans ◽  
Khalid Saeed

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.


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