View Of System Dynamics Research Articles

Impact of Emerging Transport Technologies on Freight Economic and Environmental Performance: A System Dynamics View.

Road freight transport promotes economic development while impeding the future of green development due to excessive fossil fuel use. Road freight enterprises need to adapt to stricter environmental regulations while maintaining a reasonable level of profit. However, this is not easy in a growing economy such as China's, whose domestic freight demand is increasing rapidly with economic growth. The development of emerging transport technologies (ETTs) creates great potential for reducing the negative environmental impact of road freight transport. This study considers five candidate ETTs: eco-driving, fleet platooning, vehicle utilization, optimized vehicle design, and renewable energy trucks. A system dynamics analytical framework is established to explore the long-term impact of ETTs on road profit and greenhouse gas (GHG) emissions under the uncertainty of macroeconomic development. Road freight enterprises affiliated with the Qingdao port in China are taken as a case study. The economic and environmental impact of their adoption of ETTs is projected from 2020 to 2035. The results show that the economic growth in the port hinterland leads to an increase in road freight volume and profit, but it also yields a greater amount of GHG emissions from road transport. All of the candidate ETTs exhibit a positive effect on reducing GHG emissions from road transport, but they also cause profit losses due to a high application cost, even though they reduce transport operating costs by fuel savings. The results of the Sobol sensitivity analysis show that GHG reductions are sensitive to the adoption of ETTs. Thus, a carbon-based compensation mechanism is introduced. With this mechanism, road freight enterprises should prioritize vehicle utilization, optimized vehicle design, and eco-driving in their adoption of ETTs for more sustainable development. The results provide systems-based insights into ETT deployment decisions for road freight companies.

Covid-related educational policies in action: a system dynamics view

PurposeThe purpose of this paper is to adopt a learning-based approach to portray the impact of Covid-19 on state school services in Italy, with a specific focus on the role of street-level bureaucrats and the triggering of co-creative processes.Design/methodology/approachThe study proposes a qualitative system dynamics (or SD) approach describing the implementation of Covid-related educational policies in Italy. An insight model, made of causal loop diagrams, integrates the selected multi-disciplinary literature and institutional sources, secondary data from national and local reports (about Palermo, the fifth largest metropolitan city in Italy) and insights from a panel of school street–level bureaucrats.FindingsThe study provides an insight into the impacts of governmental decisions (school closures and the subsequent need to activate distance learning during the first wave of Covid-19) at a local level. Specifically, it portrays the influences of managerial and professional discretion, infrastructural equipment and socio-economic factors favouring/deterring co-creative educational processes.Practical implicationsThe SD model highlights vicious/virtuous circles in policy implementation and suggests new managerial paths for education, more routed towards public value creation and less attached to bureaucratic procedures and the unquestioning application of performance culture.Originality/valueThe paper proposes an original and holistic approach to dealing with policy making in education and its managerial features. The research findings are considered important, not only to face the current emergency, but also to pro-actively think about the post-Covid era.

SISO Impedance-Based Stability Analysis for System-Level Small-Signal Stability Assessment of Large-Scale Power Electronics-Dominated Power Systems

To address the growing dynamic issues in the power electronics-based power system, this paper proposed an enhanced impedance-based stability analysis which can not only obtain the global view of system dynamics, but also provide a tailor-made stabilization solution by the direct use of the measured black-box models. With the proposed method, the dynamic interactions at selected multiple ports of the system are translated as multiple decoupled single-input single-output (SISO) minor loops in the frequency domain, of which the stability can be readily assessed by the SISO Nyquist stability criterion. Moreover, the oscillation mode shapes, i.e., the relative magnitude and phase of oscillated voltages and currents at the selected ports, are derived mathematically. Furthermore, the frequency-domain participation factor is defined to identify the most contributive components for the oscillations; Through impedance shaping solution of the corresponding oscillatory mode, it also provides the most effective system stability enhancement solution. EMTDC/PSCAD time-domain simulation results from an 800 MW offshore wind energy system with a realistic complexity confirm the effectiveness of the proposed method.

Vehicle-track random vibrations considering spatial frequency coherence of track irregularitives

To disclose the possible dynamic behaviours of vehicle-track systems subject to an entire railway network, random vibration analysis is of great concern in railway engineering due to the system geometric and parametric uncertainties. In this work, an emphasis is therefore put on the highly efficient simulation and numerical analysis of track geometry excitation and its induced system uncertain behaviours. Considering the spatial variability, frequency coherence and constant evolution of track irregularities, the random analysis of track irregularities belongs to a big data analysis scope. By introducing practical tools of power spectral density (PSD), frequency coherence analysis and correlated variable random simulation method, a strategy for obtaining representative and realistic track irregularity PSD samples is proposed. Besides, the modelling method of vehicle-track interactions, where versatile programming tactics to couple the track slab and subgrade elements with incompatible elemental sizes, is introduced. By combining the simulation methods of track irregularities and vehicle-track dynamic interaction, the dynamic performance of vehicle-track systems can be evaluated efficiently, and the full view of system dynamics is revealed with probabilistic characteristics.

No room at the top? A system dynamics view of the recursive consequences of women's underrepresentation in international assignments

PurposeThe expatriation literature has developed an insightful body of research on the reasons why women are not assigned abroad as frequently as men. However, the authors know very little about the systemic and recursive consequences of women's underrepresentation in international assignments (IAs), which are examined in this conceptual paper.Design/methodology/approachDrawing upon expatriation research and a system dynamics perspective, the authors propose a conceptual model to explain both women's underrepresentation in IAs and its recursive consequences.FindingsThe authors highlight how women's underrepresentation in IAs results from a complex system of recursive effects that jeopardizes women's professional development and undermines both their own career progression to top management and firms' competitive advantage and international growth. The authors argue that organizations make decisions that contravene their own interest in a competitive global context. First is that they are limiting their talent pool by not considering female candidates. Second is that they are missing the opportunity to use IAs to advance women's careers.Research limitations/implicationsThe model provides a solid grounding for future research on selecting the most effective organizational actions and designing supportive measures to disrupt the persistent dynamics contributing to women's underrepresentation in IAs. Future research could also expand our study by incorporating individual differences and the proactive role that women may take.Practical implicationsThe model points to specific managerial interventions (e.g. increased access to job training and specific training ahead of the assignment, dual-career support, women's mentoring and affirmative action) which have the potential to reduce women's underrepresentation in IAs and in top management.Originality/valueThe system dynamics approach enables a broader understanding of why women are underrepresented in IAs, how this underrepresentation further exacerbates gender segregation in international business, and how these recursive outcomes can be averted to the advantage of firms' sustainable growth.

감염병의 전파가 경제에 미치는 영향: 시스템 다이내믹스로 보기

감염병의 전파가 경제에 미치는 영향: 시스템 다이내믹스로 보기

Simulation of vacuum assisted resin transfer molding process through dynamic system analysis

Vacuum assisted resin transfer molding is a promising process in advanced composite manufacturing with a wide range of applications in industry. That potential is often misused, though, because of the lack of an efficient and reliable simulation tool to support product development. Most of the simulation methods in use today are based on Darcy’s law, which explains the permeation of a fluid in a porous medium. However, it is known that this law has limitations when applied to the context of dual-scale fibrous reinforcements: macro porosity given by fiber architecture generates resistance to flow, while the inner porosity inherent to fiber tows causes it to absorb resin, affecting the flow. The latter effect cannot be explained by traditional theory. In order to explore these limitations, this work proposes a simplified model to vacuum assisted resin transfer molding process from the point of view of system dynamics, and to prove the viability of such theory. The ultimate goal is to propose a more complete model in light of system dynamics that saves time and cost while offering the same reliability as current simulation models. In order to provide an explanation to both dual-scale phenomena, a parallel association between a resistance and a fluid capacitance is proposed. Model validation is then performed through the analysis of experimental data followed by the comparison between the Darcy infusion profile and the one predicted by the resistor-capacitor-parallel (RC-parallel) circuit model. Thus, this work is able to perform a proof of concept that leads to a novel and yet unexplored field of study.

A system dynamics view of a behavior-based safety program in the construction industry

Behavior-based safety (BBS) has received significant attention in the construction industry during the past decades. Ample evidence suggests that BBS is an effective accident prevention strategy. Past BBS literature is dominated by successful case studies, while unsuccessful cases and cases with mixed effectiveness in reducing unsafe behavior are limited. This paper reports a BBS program designed and implemented in the Singapore construction industry. The BBS program was aimed at reducing unsafe behavior in nine categories: lifting operations, excavation, working at height, work platform & access, manual handling, hot work (welding/gas cutting), plant & equipment, traffic management, and personal protective equipment (PPE). It consists of traditional BBS elements such as baseline observations, feedback, goal setting, and interventions. In contrast to other successful applications, the BBS program produced mixed results of safety behavior over 36 weeks. This paper adopts a system dynamics view to explain the mixed effectiveness. Causal loop diagrams were developed to capture behavior change mechanisms underpinned by reinforcement theory and goal setting theory, as well as dynamic effects of contextual and cognitive factors. It is concluded that the mixed effectiveness can be attributed to three main issues: dynamics of goal commitment, punishment, and monetary incentive. This paper adds to the body of knowledge of behavior safety program in terms of theoretical basis and implementation. By reviewing the BBS program holistically and reflecting upon the details of the case study, this paper offers lessons and reference for future design and implementation of BBS program in the construction industry.

Czech Cyber Security Systemfrom a view of System Dynamics

Czech Cyber Security Systemfrom a view of System Dynamics

Simulador de vuelo ejecutivo como medio de aprendizaje en la planeación de recursos de nuevas empresas bajo el enfoque del marcador balanceado

A deficient strategic planning in new companies has produced that entrepreneurs initial decisions haven’t been the appropriate and, in the long term, consequences will be reflected in the failure of many new companies. The objective of this article is to propose an executive flight simulator that will help to identify and evaluate different strategies for the development of resources of a new manufacturing company, based on the four perspectives of the balanced scorecard that will help the user to become sensitive in the impact that this will have in the performance measures. The simulator is designed under the System Dynamics view for educational purposes in MBAs, entrepreneurship or executive development programs.

Evaluating sustainability of truck weight regulations: A system dynamics view

Purpose: Targeting the problem of overload trucking in Highway Transportation of iron ore from Caofeidian to Tangshan (HTCT), this paper aims to assess long-term effects of alternative Truck Weight Regulation (TWR) policies on sustainability of HTCT. Design/methodology/approach: A system dynamics model was established for policy evaluation. The model, composed of six interrelating modules, is able to simulate policies effects on trucking issues such as freight flow, truck traffic flow, pavement performance, highway transport capacity and trucking time, and further on the Cumulative Economic Cost (CEC) including transport cost and time cost of freight owners and the Cumulative Social Cost (CSC) including pavement maintenance cost, green house gas emission cost, air pollutants emission cost and traffic accidents cost, so the effects of TWR policies on sustainability of HTCT could be evaluated. Findings: According to different values of overload ratio which a TWR policy allows, alternative TWR policies are classified into three types, which are The Rigid Policy (TRP), The Moderate Policy (TMP) and The Tolerant Policy (TTP). Results show that the best policy for sustainability of HTCT depends on the importance of CSC which is expected by the local government. To be specific, (1) if CSC is considered much less important than CEC, the local government should continue implementing the current TTP with the maximum overload ratio; (2) if CSC is considered much more important than CEC, then TRP is recommended; and (3) if CSC is considered slightly more important than CES, TMP with overload ratio of 80% is the best. Practical implications: Conclusions of this paper may help the local government design appropriate TWR policies to achieve sustainability of HTCT. Originality/value: To the best of our knowledge, this is the first effort to evaluate TWR policies on sustainability of regional freight transportation based on system dynamics modeling.

A System Dynamics View of Safety Management in Small Construction Companies

Due to unique characteristics of small construction companies, safety management is comprised of complex problems. This paper aims to better understand the complexity and dynamics of safety management in small construction companies. A system dynamics (SD) model was built in order to capture the causal interdependencies between factors at different system levels (regulation, organization, technical and individual) and their effects on safety outcomes. Various tests were conducted to build confidence in the model`s usefulness to understand safety problems facing small companies from a system dynamics view. A number of policies were analyzed by changing the value of parameters. The value of a system dynamics approach to safety management in small construction companies is its ability to address joint effects of multiple safety risk factors on safety performance with a systems thinking perspective. By taking into account feedback loops and non-linear relationships, such a system dynamics model provides insights into the complex causes of relatively poor safety performance of small construction companies and improvement strategies.

Power Flow Control and Network Stability in an All-Electric Ship

The concept of an all-electric ship, while offering unprecedented advantages from the point of view of efficiency and flexibility of operation, has introduced new challenges in terms of stability and power flow control. The advent of a full power electronics power system has raised new questions from the point of view of system dynamics, particularly when dealing with the new medium-voltage direct current distribution. The overall goal of guaranteeing a secure operation of the power system has brought researchers to consider two main approaches: reducing the dynamics of the large load to operate in a range of dynamics compatible with traditional generation systems, or making the generator set smarter through its power electronics interface. This paper compares these approaches to stable operation, focusing on the latter considered more in line with the progress of technology and in general more appealing.

A system dynamics view of the acute bed blockage problem in the Irish healthcare system

Global population ageing is creating immense pressures on hospitals and other healthcare services, compromising their abilities to meet the growing demand from elderly patients. Current demand–supply gaps result in prolonged waiting times in emergency departments (EDs), and several studies have focused on improving ED performance. However, the overcrowding in EDs generally stems from delayed patient flows to inpatient wards – which are congested with inpatients waiting for beds in post-acute facilities. This problem of bed blocking in acute hospitals causes substantial cost burdens on hospitals. This study presents a system dynamics methodology to model the dynamic flow of elderly patients in the Irish healthcare system aimed at gaining a better understanding of the dynamic complexity caused by the system's various parameters. The model evaluates the stock and flow interventions that Irish healthcare executives have proposed to address the problem of delayed discharges, and ultimately reduce costs. The anticipated growth in the nation's demography is also incorporated in the model. Policy makers can also use the model to identify the potential strategic risks that might arise from the unintended consequences of new policies designed to overcome the problem of the delayed discharge of elderly patients.

The Modeling Research on the Cost of 3PL Transportation Based on System Dynamics

In this paper, we analyse the structure of third-party logistics cost. We specially analyzes influence factor of transportation cost which account for 1/3 to 2/3 of the third-party logistics from the view of system dynamics. We establish the system dynamics model of transportation cost, and further more, we give the Vensim equations and explanation for it.

Load forecast of industries in Beijing based on system dynamics simulation method

Power consumption is influenced by many factors. A great deal of events such as the 2008 Beijing Olympic Games will greatly accelerate the increase of power consumption of Beijing. From the view of system dynamics, this paper analyses the causal relationship of these factors and constructs the simulation system for electricity and the economy to forecast power demand, which is composed of GDP and electricity consumption intensity, etc. Finally, the model was used to forecast the power consumption for Beijing and proved to be comprehensive, accurate and practical.

Firm orientations, innovativeness, and business performance: Advancing a system dynamics view following a comment on Hult, Hurley, and Knight's 2004 study

Hult, Hurley, and Knight's [Ind. Mark. Manage. 33 (2004) 429.] study reports correlations for each of the three subfactors of market orientation (competitor orientation, customer orientation, and interfunctional coordination) and innovativenss. However, their report fails to discuss the nature of these relationships. Such findings are worthy of discussion because they support prior evidence demonstrating the centrality of customer orientation in linking competitor orientation and interfunctional coordination with both innovativeness and business performance. Also, the finding that interfunctional coordination relates strongly with innovativeness supports the paradigm shift toward relationship marketing. The point needs mentioning that several different (more than one) standardized effects, structural equation models explain similar amounts of variance of business performance besides the models that Hult et al. examine. Thus, the implication by Hult et al. (p. 436) that “…learning orientation has no significant direct effect on performance” is accurate only for the model tested (shown in their Fig. 2). Applying the “quick clustering” method helps to inform interpretation when nearly all relationships among variables are statistically significant. The present article includes a proposal for advancing from one-directional structural equation modeling of innovativeness and business performance to system dynamics modeling that includes real-world feedback loops.

The Role of Knowledge in Resource Allocation to Exploration versus Exploitation in Technologically Oriented Organizations*

ABSTRACTDecisions regarding research and development (R&D) activities of an organization greatly affect the fiscal and market outcomes of technologically oriented firms. Yet, the resource allocation choices between these two activities are tied strongly to an organization's technology knowledge. Technological knowledge is itself a resource that the firm can manage to achieve strategic and competitive advantage. In this paper, the authors present a system dynamics view of the decomposition of R&D efforts into explorative and exploitive activities and the resultant knowledge‐specific and performance outcomes from the decision to focus on one type of activity or another. Four factors are shown to affect the relative value of innovative knowledge to the organization: resource availability, exogenous competition, aging of knowledge bases, and adaptive capacity, a firm's ability to adapt to its environment. A variety of long‐ and short‐term strategic issues are discussed in relation to these forces.