Vulnerability black markets (VBMs) are sites for trading malicious tools targeting software vulnerabilities. VBMs enable different actors to access malware and use them to attack vulnerable computers. This article presents an economic rationale for the existence and continuity of VBMs. It is assumed that buyers and sellers decision to trade in the black markets depend upon their perceived costs and benefits. As long as the expected utilities of engaging in the black markets are higher than the costs, buyers and sellers will continuously trade in VBMs. A system dynamics (SD) model is developed to capture such problem. Concepts from market-for-crimes theories are adopted into the model, since they provide a useful perspective for explaining criminal behavior such as in VBM.
The fundamental objective of this paper is to present a dynamic framework to test the two competing theories; the Pecking Order Theory (POT) and the Trade-off Theory (TOT); that explain the capital structure behavior of firms. For this purpose we use System Dynamics (SD) method to develop a generic simulation model of a manufacturing firm based on generally accepted accounting principles. We model the capital structure decision conforming to POT and TOT to test the two competing theories, in isolation and in combination. The firms may pursue POT or TOT for their capital structure decision, but it is generally agreed that while doing so their prime objective is to maximize the firm value. Hence we presume that the managers stick to the core objective of firm value maximization.
Water Resource Carrying Capacity (WRCC) is an important metric for regional water management in China. Shandong Province of China faces a serious water shortage if WRCC is not managed at a sustainable level. This study focuses on applying system dynamics methodology to evaluate different development scenarios and their associated WRCC for Shandong. System characteristics of local water resources and demand in Shandong are captured and modeled using system dynamics within VENSIM software. The dynamic model of Shandongs WRCC consists of 5 subsystems: agricultural development, population growth, industry and tertiary industry, water resources, and water pollution. Historical data are used to calibrate model parameters. Impact on the WRCC is assessed through three growth scenarios: modest industrial growth, aggressive industrial growth, growth combined with wastewater recycles. Based on simulation results, WRCC that most likely can sustain economic growth without overstressing the water supply is one with modest growth combined with wastewater recycle.
Possible short, medium and/or long term scarcity of minerals/metals may actually pose a threat to modern societies. Its potentially disruptive societal consequences qualify this issue for exploration from a world/regional security point of view. Hence, the forces of System Dynamics modelling and simulation and Exploratory Modelling and Analysis are joined in this paper to explore the dynamic complexity of potential mineral/metal scarcity under deep uncertainty and to create useful scenarios for inter/national risk assessment.
In this paper, an Exploratory System Dynamics model of a concerted run is first of all presented. The immediate cause for modelling a concerted bank run was the mediatised call for a run on the DSB bank. This Exploratory System Dynamics model was developed the morning of the call for the bank run, before the start of the ensuing bank crisis, in order to quickly foster understanding of possible dynamic behaviours of concerted bank runs and to perform rough-cut policy/strategy analyses. The model is subsequently used to illustrate the
This follow-up paper presents several new 'hot' cases for teaching and testing System Dynamics. The cases were developed between April 2009 and January 2010 for the Introductory System Dynamics course at Delft University of Technology in the Netherlands. These cases can be used for teaching and testing introductory and intermediate System Dynamics courses at university level as well as for self study.
The main goals of this paper are to explain and illustrate Exploratory System Dynamics and Exploratory System Dynamics Modelling and Analysis, which are both useful for exploration of, and decision-making in, dynamically complex issues that are deeply uncertain. First, the need for exploratory approaches is discussed. Second, different exploratory approaches are briefly introduced. Third, a typology of safety and security issues/crises in terms of degrees of complexity, uncertainty and urgency is proposed. Different types of inter/national safety and security issues for which exploratory analyses may be useful are listed too. And the application of these exploratory approaches is subsequently illustrated on some of these issues, more precisely on (i) an acute financial crisis (the concerted bank run on the DSB Bank), (ii) an imminent pandemic flu crisis, and (iii) plausible mineral/metal scarcity crises. The paper ends with some conclusions, lessons learned, and a discussion of future work.
This paper presents a small exploratory System Dynamics model related to the dynamics of the 2009 flu pandemic, also known as the Mexican flu, swine flu, or A(H1N1)v. The model was developed in May 2009 in order to quickly foster understanding about the possible dynamics of this new flu variant and to perform rough-cut policy explorations. Later, the model was also used to further develop and illustrate the use of Exploratory System Dynamics models as scenario generators for Exploratory Modelling and Analysis.
Stocks and flows are basis of dynamics. Understanding of stock and flow is crucial in comprehending and managing problems such as global warming and national debt. Yet previous experimental studies have found that people perform poorly in simple stock-flow tasks. However, many do have a notion of accumulation in terms of calculating running total, adding or subtracting items to keep track of a running tally. Here a pre-test-treatment-post-test experiment was designed to test the hypothesis that peoples understanding of stock and flow behaviours will improve after being asked to reflect on a cognitive conflict, generated by utilizing their running total calculation. Comparisons with a conventional approach to teach stock and flow dynamics and without teaching were also done. Results show that improvements were not significant; the hypothesis lacks support. On the other hand, the conventional approach produced significant improvement. Possible explanations of the results and their implications for education on dynamics, communication of complex dynamic problems and policy insights are discussed.
The insecurity crisis that Mexico is facing has taken to a reform in the Federal Law to impel the development of a new federal police, with trained elements in knowledge and tactics that allow them to face the crime of one more effective and coordinated way. The present work shows the results of a project designed to evaluate how feasible would be the implementation of such law. It required integrating a team with officers of the Federal Police force to design a dynamic model to analyze the key processes related to the transition of the current force to a new structure required for the law. This document presents the methodological frame, the design of the model some findings about the process and a scenario analysis to visualize some strategies that could be implemented in order fulfill the requirements of the law.