System Dynamics Approach Research Articles

The impact of circular economy strategies on municipal waste management: A system dynamics approach

The low levels of reuse and recycling of solid waste in cities in developing countries can be attributed to decision-making processes with sub investment that do not consider waste streams, recovery capacities, and potential for recycling. This is due to a lack of understanding of the systemic structure of urban waste management.This article presents the development of a model of an urban waste management system that integrates decisions based on strategies that close cycles, belonging to the concept of a circular economy. These strategies aim to increase the potential use of organic waste, plastics, and glass.The model was built using the Systems Dynamics methodology, which allows obtaining mathematical models for the study and observation of trends and future scenarios of complex systems. The model is made up of three modules: health, financial, and circular economy. The strategies evaluated and compared in the simulation environment were: Economic incentives at the price of the material used; Increase in waste sorting capacity; Increase in the capacity to use waste.Methodologically, novel mathematical representations were achieved for the estimation of the useful life of sanitary landfills. Likewise, a mathematical formulation was found for the automatic evaluation of the efficiency in the capacity to use different wastes, which allows to know the need for investment or increase of capacity to use the type of waste evaluated.Using novel mathematical representations, this study achieved a methodological breakthrough in estimating the useful life of sanitary landfills and waste transformation efficiency. These representations also enable the automatic evaluation of how effectively different types of waste can be utilized. This information can then be used to determine the need for investment in, or expansion of, the capacity to handle specific waste types or to increase the overall waste collection capacity of the city.

How Does a Decision-Making Tool Enhance Spent Mushroom Substrate Valorization into Polysaccharides?

In mushroom farming, one kilogram harvested results in about five kilograms of spent mushroom substrate (SMS), posing an environmental management challenge. As an in-tune work with the concepts of circular economy, cleaner production, and waste minimization, this study has developed a mathematical model than analyzes the valorization potential of SMS through polysaccharide production. The in-depth mathematical model is based on a system dynamics approach, which explains the interactive interplay amongst the production process, related costs, energy consumption, and caused emissions. The model has been developed in a generic way. Meaning that it can be re-adjusted flexibly for a different cleaner production process. A user-friendly interface has been developed. Users can easily maneuver around the variables within the model that offers instantaneous insight into the environmental and economic impacts of SMS valorization. This interface was later integrated into an educational context to serve as an interactive decision-making tool for cleaner production modelling. The main purpose of the developed tool was to favor understanding of causalities between production chains, energy consumption, labor, emissions, and expenses. This tool has been tested on master’s degree students in a cleaner production course. Survey results show that 82% of students report the need to incorporate similar decision-making tools in their learning curriculum. In sum, the application of system dynamics to the valorization of SMS does not only present an attractive solution for this environmental problem but also shows great potential in setting educational backgrounds for an interactive and close-to-life learning process. It is recommended to develop more interactive tools available for students.

Will Changing Habits Ensure Sustainable Mobility: System Dynamics Modeling Examples from Municipalities in Four Countries

The transportation industry stands out as a significant contributor to world emissions, which presents a significant obstacle to the process of decarbonization. This study recommends a comprehensive plan that addresses emissions not just on a national level but also on a local and individual level, with an emphasis on using a multi-dimensional approach. Our study aims to support municipalities in assessing and mitigating transportation-related emissions by using a system-dynamic approach and introducing a state-of-the-art instrument. In contrast to conventional assessments, which are primarily concerned with technical criteria, our approach takes into account the everyday routines of inhabitants as well as their willingness to accept sustainable policies.Dynamic modeling enhances our understanding of the intricate correlation between technical metrics and socio-behavioral dynamics. This allows us to provide municipalities with a strong basis for the creation of effective initiatives aimed at reducing emissions. This research adds to the subject of sustainable urban planning by promoting the increased public acceptance of sustainable mobility schemes and encouraging active public involvement. This analysis allows municipalities to build policies that not only target technical emissions but also integrate smoothly into the social framework of the local community. This is made possible by the fact that this study emphasizes the relevance of holistic and community-centered approaches. For municipalities that are attempting to navigate the complexities of emissions reduction in the transportation sector, it gives significant insights that highlight the requirement of policies that are both inclusive and adaptive to promote a sustainable urban future.

Improving collaborative innovation performance in megaprojects: a system dynamic approach

PurposeThe development and evolution of stakeholder collaborative innovation in megaprojects is impacted by various influencing factors. The effect of influencing factors on collaborative innovation performance (CIP) in megaprojects is not a simplistic linear relationship but an iterative and non-linear relationship that requires a dynamic perspective to analyze. Therefore, this paper adopts the system dynamic (SD) approach to investigate the dynamic and interactive relationships between the CIP and the influencing factors.Design/methodology/approachThe study first develops a research framework with the system boundary of “CIP system – organizational collaboration subsystem – knowledge collaboration subsystem – strategic collaboration subsystem”. Then, the causal relationship model, the stock-flow model, and the mathematical equations were determined based on the literature review and the expert interviews. Finally, five performance improvement scenarios were designed according to the practice context of CIP in megaprojects, and simulations were performed using the Vensim PLE software to investigate the CIP from a dynamic perspective.FindingsThe findings reveal that the effect of different influencing factors on CIP grows non-linearly, with the cumulative effect becoming more pronounced as time advances. The incentive mechanism has the most significant effect, and the combined effect of multiple influencing factors has a highly significant facilitating effect on improving CIP. Strategic collaboration, organizational collaboration and knowledge collaboration are mutually conditional and reinforcing with each other, which ultimately promotes the improvement of CIP.Originality/valueThis study uncovers the inherent pattern and the interactive dynamic mechanism of factors for improving CIP in the context of megaprojects. It enriches the theoretical research in the area of collaborative innovation in megaprojects and provides practical management strategies for improving CIP.

Does a GP service package matter in addressing the absence of health management by the occupational population? A modelling study.

To assess the influence of supply and demand factors on the contract behavior of occupational populations with general practitioner (GP) teams. We employed a system dynamics approach to assess and predict the effect of the general practitioner service package (GPSP) and complementary incentive policies on the contract rate for 2015-2030. First, the GPSP is designed to address the unique needs of occupational populations, enhancing the attractiveness of GP contracting services, including three personalized service contents tailored to demand-side considerations: work-related disease prevention (WDP), health education & counseling (HEC), and health-care service (HCS). Second, the complementary incentive policies on the supply-side included income incentives (II), job title promotion (JTP), and education & training (ET). Considering the team collaboration, the income distribution ratio (IDR) was also incorporated into supply-side factors. The contract rate is predicted to increase to 57.8% by 2030 after the GPSP intervention, representing a 15.4% increase on the non-intervention scenario. WDP and HEC have a slightly higher (by 2%) impact on the contract rate than that from HCS. Regarding the supply-side policies, II have a more significant impact on the contract rate than JTP and ET by 3-5%. The maximum predicted contract rate of 75.2% is expected by 2030 when the IDR is 0.5, i.e., the GP receives 50% of the contract income and other members share 50%. The GP service package favorably increased the contract rate among occupational population, particularly after integrating the incentive policies. Specifically, for a given demand level, the targeted content of the package enhanced the attractiveness of contract services. On the supply side, the incentive policies boost GPs' motivation, and the income distribution motivated other team members.

An evolutionary game and system dynamics approach for the production and consumption of carbon-labeled products-based on a media monitoring perspective

Carbon label is acknowledged as an effective way to combat the problem of global warming. As a powerful way to encourage individuals to adjust their consumption patterns and to promote the development of green consumption, carbon-labeled products are widely developed in China. To reveal the production and consumption process of carbon-labeled products, the present study constructs a tripartite game model consisting of the government, carbon-labeled products manufacturers and consumers based on a media monitoring perspective. The evolutionary stability strategy (ESS) is firstly determined by solving the replication dynamic equations and stability analysis of the equilibrium point, followed by the strategy analysis and sensitivity analysis through numerical simulation. The results show that media supervision can effectively complement and constrain government supervision. In addition, it can promote enterprises to standardize production and enhance consumers' trust and willingness to buy carbon-labeled products. The introduction of media supervision can well realize the ideal equilibrium of "effective government supervision, enterprise compliance and consumer support for purchase".

A system dynamics approach for sustainable groundwater management considering climate change, inter-organizational relationships, and domestic water saving

This article uses system dynamic modeling to examine the relationship between water allocation from the Ilam dam and groundwater fluctuation, as well as the effects of climate change, changes in inter-organizational relationships, and water demand management on water allocation and groundwater level fluctuations. The results showed that agricultural water allocation has a direct effect on groundwater level fluctuations. In the first scenario, which examined the effects of climate change, the comparison of three climate change scenarios (SSP126, SSP245, and SSP585) was carried out. The results illustrated that with temperature increasing and precipitation decreasing occurred in SSP585, the groundwater drawdown increases about 0.8 m more than SSP126. The second scenario examined the effects of changes in inter-organizational relationships. Based on the results of centrality measures in the social network analysis method, it was found that the organizational power of the stakeholder organization in the agriculture sector is greater than the ones in the environment sector. This causes the allocation to the agriculture sector to be prioritized over the environment. This scenario was analyzed by assuming a change in organizational power and giving priority to the water allocation of the environmental sector. The results showed that environmental needs (maximum 0.3 MCM) were almost entirely met in the second scenario, compared to the basic scenario. Also, the decrease in agricultural water allocation has led to an increase in groundwater usage by farmers, resulting in a 20 cm drop in groundwater levels. Therefore, regarding the sustainable management of water resources, directing attention towards alternative livelihoods for farmers can contribute to environmental water rights and the remediation of aquifers. The third scenario examined the effects of water demand management. The results showed that saving 20–25% of water in the domestic sector can reduce 40–50 cm maximum groundwater drawdown which align with sustainable groundwater management.

A system dynamics approach for cost-benefit simulation in designing policies to enhance the cybersecurity resilience of small and medium-sized enterprises

The small and medium-sized enterprises (SMEs) with limited investment capacity are likely to be lax in enhancing their cybersecurity. Therefore, to strengthen cybersecurity at a national level, governments must intervene in the market by using support or regulatory policies to overcome market failures and address weaknesses. This study reviewed the efficiency of policy options to improve corporate cybersecurity resilience for SMEs that require government support, unlike large companies that can invest in security on their own. To achieve this, a causal loop diagram was created and analyzed from the perspective of system dynamics. The model incorporated government support variables and the decline in capabilities over time into the existing corporate security investment model reflecting the standard framework for cybersecurity from NIST. The simulation scenarios were constructed based on policy options considered by the Korean government. These include 1) pre-incident or post incident support services, and 2) management through tax credits and regulation. The results indicated that incentives, specifically tax credits, rather than regulation, were more effective in strengthening cyber resilience. This study describes the investment and internal capability development of a company affected by government policy, which is an external factor, and changes in profits can be observed by adding the company's profits and costs as variables. This profit variable allows for the comparison of a company's cyber resilience across scenarios. Additionally, if the government provides direct support immediately after a hacking incident, the company can recover more quickly. If these benefits are known and if the reporting of hacking damage is activated, cyber threat visibility will be secured by revealing hacking attacks that have been secretly conducted. Governments can use cyber threat visibility to strengthen national cybersecurity.

Simulating the corrective actions affecting system availability: a system dynamics approach

Purpose This paper aims to simulate vital corrective actions (CAs) affecting system availability through a system dynamics approach based on the results obtained by analyzing the causal relationships among failure modes and effects analysis elements. Design/methodology/approach A stock and flow diagram has been developed to simulate system behaviors during a timeframe. Some improvement scenarios regarding the most necessary CAs according to their strategic priority and the possibility of eliminating root causes of critical failure modes in a roller-transmission system have been simulated and analyzed to choose the most effective one(s) for the system availability. The proposed approach has been examined in a steel-manufacturing company. Findings Results indicated the most effective CAs to remove or diminish critical failure causes that led to the less reliability of the system. It illustrated the impacts of the selected CAs on eliminating or decreasing root causes of the critical failure modes, lessening the system’s failure rate and increasing the system availability more effectively. Research limitations/implications Results allow managers and decision-makers to consider different maintenance scenarios without wasting time and more cost, choosing the most appropriate option according to system conditions. Originality/value This study innovation would be the dynamic analysis of interactions among failure modes, effects and causes over time to predict the system behavior and improve availability by choosing the most effective CAs through improvement scenario simulation via VENSIM software.

Supply and demand of beef in Indonesia: a system dynamics approach

This research paper thoroughly analyzes a constructed model that aims to investigate the intricate dynamics of beef supply and demand in Indonesia. The main aim of this study is to enhance comprehension of the diverse factors that influence beef supply and demand within Indonesia’s beef production system. The disparity between beef consumption and beef production in Indonesia has been acknowledged as contributing to the nation’s reliance on beef imports, impacting food security inside the country. The per capita beef consumption in Indonesia remains relatively low compared to the global average. Indonesia has achieved a level of beef self-sufficiency amounting to 71%. However, the Indonesian government has set a goal of attaining a 90% fulfillment of domestic production to satisfy the increasing demand of the people adequately. This research utilizes a qualitative system dynamics methodology to examine the impacts of pricing, cow population, and beef production technology in Indonesia by applying causal loop and stock-flow diagrams. The findings of this study will offer significant insights to assist the government in understanding the causal relationships between several factors related to the improvement of beef production policies in Indonesia.

Exploring a pathway to optimise the carbon tax policy in terms of the economy, the environment and health: A scenario-based system dynamics approach

The carbon tax, a pivotal policy instrument in tackling climate change, holds the potential to significantly influence the development of society. To comprehensively analyse the effectiveness of the policy on carbon taxation and explore its possible optimisation path, this study utilizes system dynamics theory to establish a simulation model. A detailed analysis and evaluation of this policy is then conducted from the perspectives of the economy, the environment, and health. To guarantee the precision of the simulation model, a new, comprehensive evaluation method is proposed, which can test the degree of fit of the relative trend and absolute data of the simulation model with reality. The findings reveal that, despite its negative economic implications, a carbon tax policy has positive ramifications for the environment, energy, health, industrial structure, and carbon intensity targets. Furthermore, the synergistic reinforcement effect of R&D and new energy support policies on carbon taxation surpasses the impact of any individual policy alone. Notably, the influence of auxiliary policies has a temporal difference on this policy. Based on these insights, the study concludes with practical policy recommendations.

A system dynamics approach for the development of a Regional Innovation System

Regions play an important role in the global economy by driving research and innovation policies through a major tool, the Regional Innovation System (RIS). The RIS is a social system that encompasses the systematic interaction of the various organizations that comprise it, to improve local knowledge and innovation. It consists of interconnections of various public and private sector institutions, whose activities and interactions create, introduce and diffuse innovations. This paper outlines the methodology employed in developing and validating a mathematical model of Regional Innovation Systems, utilizing the system dynamics approach. To provide a demonstration of the aforementioned concept, the proposed model will then be implemented in the RIS of two specific regions in Greece, namely Western and Central Macedonia. Within this context, various policies will be formulated to modify the indicators of Smart Technology, with the objective of assessing their influence on the overall regional development of the aforementioned regions. The model focuses on the functional structure of the RIS, separating it in six diverse, interacting subsystems consisting of different components, captured by a total of 38 different factors which can be quantitatively assessed.

An integrated FAHP-SD model to assess and allocate of critical risks for public-private partnership transportation projects

The present paper aims to identify and evaluate risks in transportation projects carried out through public-private partnerships (PPP) and proposes a model for allocating critical risks among stakeholders. The study utilizes the fuzzy analytic hierarchy process (FAHP) to prioritize risks and a system dynamics (SD) approach to develop a causal model for risk allocation. Thirty risks are identified and categorized into five primary risk categories: government, financing, operational, social, and organizational. Operational risks are found to be the highest priority, followed by organizational, economic, political, and social factors. Using the Pareto principle, eight critical risks are identified. The proposed SD-based risk allocation model is applied to a case study of the Shiraz-Isfahan Freeway Project. The results indicate that the project can be completed within the set timeframe of six years, but it would incur a 46% higher cost than initially estimated if 62% of the risk of exceeding the financial limit is allocated to the employer. This study provides valuable insights into risks associated with transportation projects undertaken through PPP. The proposed model offers stakeholders an effective and efficient approach to allocate risks. By addressing these risks, stakeholders can enhance the success and efficiency of PPP transportation projects.

System dynamics approach for assessing the performance of safety management systems in petrochemical plants

Accidents in process industries, such as chemical, petrochemical, and refinery sectors, often stem from intricate causes. Consequently, safety management systems (SMS) have emerged as crucial mechanisms for accident prevention. In process industries, this is an interrelated and sociotechnical system consisting of numerous interacting components. However, current safety management approaches appear to be limited by linear thinking in terms of enhancing safety performance. Adopting systems thinking that considers the feedback loop and time delay is necessary to improve the efficiency and effectiveness of system performance. This study proposes a model that can predict the performance of SMS in petrochemical plants to manage risks using system dynamics (SD). Methods are proposed to build causal relationships in SMS and to develop a simulation model grounded in SD, facilitating performance evaluation within process industries. The proposed model is applied to an organization as a case study, and scenario-based simulations are performed. The case study results indicate that senior management interests are more influential to safety performance. The model is expected to be able to forecast the performance level of SMS and help decision-makers identify better policies and obtain insights to improve safety.

Modeling residential photovoltaic adoption: A system dynamics approach for solar energy expansion

Using a system dynamics approach and the Generalized Bass model, we model the diffusion of Photovoltaic System (PVS) adoption among Iranian households. The model recreates the interplay between economic, social capital, managerial, political, and technical factors influencing PVS adoption. While existing literature indicates that technology diffusion typically follows an S-shaped growth pattern, this is not true in Iran. Our research reveals that the deviation can be attributed to the low estimated values of innovation and imitation coefficients. Our study emphasizes the positive impact of factors such as society's awareness and interest, environmental concerns, and government-provided incentives while highlighting the negative influence of factors like inflation and increased payback periods on PVS adoption. This study provides insights for practitioners and policymakers to develop effective strategies for PVS adoption, fostering a sustainable energy future in Iran and other emerging nations.

Revolutionising sustainability using a new triplet: A system dynamic model

The theory of sustainability has been analysed and implemented in various sectors to minimise the consumption of limited resources and to consume the fullest potential of existing resources. The triple-bottom concept of sustainability covers all possible interactions within an ecosystem. However, the dynamic nature and interconnectivity of sustainability systems, such as the environmental, economic, and social systems, are quite complex to curb sustainability challenges. The modification in one system may create disturbances in other systems. Based on the existing studies on sustainability, this study explored how these systems can be optimised by analysing the relationship between each side of sustainability triangle by 3As, i.e., Adaptability, Affordability and Availability, to determine their impacting macro and micro flows. The reinforcement can be achieved between social-environment by adaptability, social-economics by affordability and economics-environment by availability. These 3As synergise sustainability systems if inflows and outflows in sustainability systems are optimised. The system dynamic approach was adopted to model and examine all possible 3As’ inflows and outflows comprehensively in urban ecosystems. Micro flows are analysed for the associated macro flows for each factor of triplet. The results suggest that although sustainability systems are complex but not wicked in nature, it is required to focus on macro and micro flows of adaptability, affordability and availability in each system. This study may serve as a source of information for improving and maintaining sustainability in industries, businesses and the policy makers to optimise their existing resources on this comprehensive triplet model.

Modeling sustainable bioethanol supply chain in Australia: A system dynamics approach

The growing energy demand and concerns over fossil fuel consumption underscore the need for a shift to renewable energies and biofuels. Concurrently, the rising global population and increased biofuel demand strain the food supply system, requiring enhanced production capabilities. By using a system dynamics model, this study investigates the intricate relationship between bioethanol production and food security in Australia, emphasizing the essential balance for a sustainable bioethanol supply chain. The research explores the interplay among population, food supply, and energy supply subsystems, projecting diverse bioethanol production scenarios until 2050. Findings reveal constraints within the Australian bioethanol supply chain, with current capacity meeting demand at a 1.5 % bioethanol blend rate to gasoline. However, surpassing 3.4 % demands significant capacity expansions incurring substantial costs. At a 5 % blend rate, it is imperative to augment the production capacity to 1275 million liters of bioethanol by 2050. The study underscores the limitations of relying on sorghum for bioethanol production, emphasizing the strategic need to embrace alternative sources such as wheat starch waste and molasses. Addressing the challenge of supplying sufficient food for consumption and energy production, our research advocates for a shift towards fuels produced without edible resources. These insights are vital for policymakers and industry stakeholders, contributing to the understanding of complexities in establishing a sustainable bioethanol industry while ensuring food security and environmental sustainability.

Assessment of Climate Change-Induced Water Scarcity Risk by Using a Coupled System Dynamics and Bayesian Network Modeling Approaches

The water scarcity risk induced by climate change is contributing to a sequence of hydrological and socioeconomic impacts. Certain numbers of related impacts are locked in already and are expected to be much greater in the future. So, there is still a lack of understanding of its dynamics, origin, propagation, and the mutual interaction of its drivers. In recent years, several model-based approaches have been introduced to tackle the complexity, dynamics, and uncertainty of water scarcity specifically. However, the coupled modeling while addressing different aspects of the risk of water scarcity under the climate change scenarios has been rarely done. For bridging this gap, in this research, the combination of complementary System Dynamics modeling and Bayesian Network was applied to Qazvin Plain in Iran with five AOGCM models under two Shared Socioeconomic Pathways (SSP) scenarios (126 and 585). Key findings of this research show: 1) Baseline risk assessment indicates a low probability of water scarcity; however, in the future 30-year time horizon with continuous change in hazard, vulnerability, and exposure for SSP126, the risk fell in the extreme category with an average probability of 41%. Under SSP585, the risk varies between extreme and high categories with an average probability of 47%. 2) Economic development, particularly regional gross domestic product (RGDP) in 2045–2054 in SSP585 can diminish the negative projected consequences of climate change and therefore investments in adaptation policies could offset negative consequences, highlighting the role of economic growth in climate resilience. 3) It is projected that crop yield and income will receive the largest negative effects due to cutting back the agriculture area. 4) Considering the interplay of climate change, economic development, and water extraction policies is essential for the design, operation, and management of water-related activities. The proposed integrated methodology provides a comprehensive framework for understanding climate change-induced water scarcity risks, their drivers, and potential consequences. This approach facilitates adaptive decision-making to address the evolving challenges posed by climate change.

A System Dynamics Approach to Feedback Processes in Project Scheduling

Projects, as catalysts for proactive transformation, offer a temporary and adaptable framework that effectively handles complexities (or uncertainties) within a competitive corporate landscape. Hence, the use of an effective project management framework, such as Dynamic Project Scheduling (DPS), is a method to handle intricacies in order to accomplish organizational objectives. DPS refers to a triangle interaction involving baseline scheduling, schedule risk analysis, and project control while supporting schedule adjustment in response to changes and uncertainties. However, there is a lack of information regarding studies that have investigated the feedback mechanisms among DPS components. This study was designed to examine the counterintuitive relationships between these components using system dynamics. The quantities within the DPS system were identified and defined. A casual loop diagram was used to illustrate the interactions among these quantities. Subsequently, a Stock and Flow Diagram (SFD) was created to identify the inputs, states, and flow mechanisms within the DPS. Using the SFD, a system dynamics expression was generated which was then employed to compute the rate of change of the Budgeted Cost of Work Remaining (BCWR) for two projects at different time intervals. The results properly indicated the period of idleness during project execution. The use of BCWR rather than schedule variance provides a more effective visual representation for evaluating performance and tracking progress. The BCWR and planned value exhibit contrasting trends, highlighting the importance of earned value quantities in project control. The use of system dynamics in project management can enhance the planning and scheduling phase, allow project managers to monitor pertinent performance measures, and optimize project outcomes through informed decisions.

The system dynamics approach for a global evolutionary analysis of sustainable development

The challenge of pursuing sustainable development highlights the relevance of the complex mechanisms through which natural and social selection processes affect and are affected by the economic system. Current economic development is unsustainable because it fails to generate long-term systemic compatibility between firms and their natural and social environment. This paper evaluates the issue from an evolutionary perspective by conceptualising unsustainability as the emergence of negative macro-selection effects, arising from both the natural and social domains, and argues for a methodological need for closer integration of system dynamics modelling within the evolutionary field. The Earth4All model is then used to illustrate the complex interactions between economic, social, and natural selection processes. The model results illustrate that the current global development trajectory is strongly unsustainable from both a natural and a social perspective, leading to the emergence of relevant natural and social macro-selection mechanisms, whose systemic interactions bring further complex adverse effects.