System Dynamics

The Region of Yogyakarta (DIY) is one of the regions in Indonesia. Community growth in Yogyakarta reaches 1.34% in 2017 which can cause various problems such as unemployment community that continues to grow every year. In addition, another serious problem in Yogyakarta is high congestion which is implicated by the increasing number of population in DIY. Those problems have a bad influence on regional cash which is very useful in the development of the area. This study aims to increase regional cash of DIY by considering available employment and traffic congestion. Because the problem is so complex, a system dynamics approach is used to solve it. Based on the simulation results using Powersim 2005, the main cause of unstable regional cash is the high cost of building new roads, the cause of high cost of building new roads is congestion, and the cause of congestion is the high demand for vehicles by residents of the Yogyakarta area. Therefore, it is necessary to reduce the level of demand for vehicles to increase the cash of the DIY area. By reducing the demand for vehicles to 0.00003, which initially 0.00005 has succeeded in making the regional cash stable and increasing continuously. In addition, to increase employment in order to eliminate the population unemployment in Yogyakarta, it can be done by increasing the growth rate of new companies. By increasing the growth rate of the new company to 1.2 which initially 1 has succeeded in making employment increased continuously.

This paper describes the development of a generalized agent -based simulation tool for studying manpower and personnel management behaviors. The subject matter of the simulation are complex organizational behaviors found within Uni ted States Navy Manpower and Personnel processes. Behavior of such a complex system is typically associated with a hierarchi- cal structure in which the lowest level agents are

Theory informs us of the differences between principles and methods used to build System Dynamics and Agent Based Models. However, little is known about how the paradigms are applied in practice and the subsequent difficulties encountered. In order to ...

In this paper, we develop a framework to optimally manage the time-phased deployment planning of a new technology, namely Advanced Metering Infrastructure, in the Utility industry. Advanced Metering Infrastructure enable two-way communication between residential and commercial customers and the Utility grid, so that energy consumers may respond to price signals during stressful conditions in the grid in a price-sensitive fashion, and reduce the overall stress in the grid. It also enables consumers to shift discretionary energy loads from stressful, peak periods to off-peak periods. We present an end-to-end solution framework for addressing the various analytical challenges that are involved in developing an optimal deployment plan, from a business case development perspective. Our solution framework uses a judicious combination of system dynamics modeling, econometric modeling and mathematical programming based optimization modeling. A system dynamics model is used to estimate the d...

This paper revisits the use of trend forecasting to determine ordering policy in supply chains by viewing it as a part of the control process for making the supply responsive to demand. Trend forecasting is often used to assess demand—a tracked variable in the control context, which drives supply—a tracking variable. Used in this way, it is often observed to increase instability creating the so-called bullwhip effect. Trend is used on the other hand with reliability to increase stability in controller control, but with the difference that a trend of a ...

The tidal migration, temporal and spatial patterns in feeding of the surface-swimming four-eyed fish Anableps anableps (Anablepidae) were studied in a macrotidal mangrove area in north Brazil to exemplify the ecology of a tropical intertidal fish. Visual censuses in the main channel showed that abundances were high at low water (LW) and low at high water (HW). Anableps anableps entered the intertidal creeks with the first flood rise. They fed in the inundated mangrove at HW and returned gradually after the ebb current maximum to concentrate again in the subtidal parts of the main channel at LW. This pattern occurred at neap, mid and spring tides throughout the year. The tidal migration was triggered by water level, not by time. In the study area the diet of A. anableps caught with block nets was dominated by intertidal red algae (Catanella sp.). Other important food items were Insecta and Grapsidae. The combination of high inundation and daylight (spring tide-day) provided the best foraging conditions, probably emphasizing the importance of the above-water eye. Darkness and low inundation was linked to poorest foraging conditions (neap tide-night). The quantity of food consumed by A. anableps was clearly influenced by the factors tide, time of day and creek location, but not by size and sex. The qualitative composition of the diet was not influenced by any of the factors, except for mud, which was only ingested at neap tides. The temporal and spatial variability in food consumption suggests that food web modelling in macrotidal areas may lead to misinterpretations of the overall systems dynamics if the spring and neap tide alternation and the diurnal cycle are not considered.

The significance of environmental protection is well known in today's world. The execution of any program depends on sufficient knowledge and required familiarity with environment and its pollutants. Taking advantage of a systematic method, as a new science, in environmental planning can solve many problems. In this article, air pollution in Tehran and its relationship with health and population growth have been analyzed using dynamic systems. Firstly, by using casual loops, the relationship between the parameters effective on air pollution in Tehran were taken into consideration, then these casual loops were turned into flow diagrams, and finally, they were simulated using the software Vensim in order to conclude what the effect of each parameter will be on air pollution in Tehran in the next 10 years, how changing of one or more parameters influences other parameters, and which parameter among all other parameters requires to be controlled more.

The management of occupational health and safety (OHS) including safety culture interventions is comprised of complex problems that are often hard to scope and define. Due to the dynamic nature and complexity of OHS management, the concept of system dynamics (SD) is used to analyze accident prevention. In this paper, a system dynamics group model building (GMB) approach is used to create a causal loop diagram of the underlying factors influencing the OHS performance of a major drilling and mining contractor in Australia. While the organization has invested considerable resources into OHS their disabling injury frequency rate (DIFR) has not been decreasing. With this in mind, rich individualistic knowledge about the dynamics influencing the DIFR was acquired from experienced employees with operations, health and safety and training background using a GMB workshop. Findings derived from the workshop were used to develop a series of causal loop diagrams that includes a wide range of dynamics that can assist in better understanding the causal influences OHS performance. The causal loop diagram provides a tool for organizations to hypothesize the dynamics influencing effectiveness of OHS management, particularly the impact on DIFR. In addition the paper demonstrates that the SD GMB approach has significant potential in understanding and improving OHS management.► We conducted a system dynamics group modelling workshop for a major drilling and mining contractor in Australia. >Rich individualistic knowledge was acquired in the workshop. ► Causal loop diagrams were created representing the complex factors influencing management of occupational health and safety. ► Paper demonstrates that the group model building approach has significant potential.

A universal controller is designed for cascade systems, involving dynamic uncertainty, unknown nonlinearities, exogenous disturbances and/or time-varying parameters, capable of guaranteeing prescribed performance for the output tracking error, as well as uniformly bounded signals in the closed loop. By prescribed performance we mean that the output tracking error should converge to a predefined arbitrarily small residual set, with convergence rate no less than a certain prespecified value, exhibiting maximum overshoot less than a sufficiently small preassigned constant. The proposed control scheme is of low complexity, utilizes partial state feedback and requires reduced levels of a priori system knowledge. The results can be easily extended to systems affected by bounded state measurement errors, as well as to MIMO nonlinear systems in block triangular form. Simulations clarify and verify the approach.

This paper investigates the system stability of a sampled-data fuzzy-model-based control system, formed by a nonlinear plant and a sampled-data fuzzy controller connected in a closed loop. The sampled-data fuzzy controller has an advantage that it can be implemented using a microcontroller or a digital computer to lower the implementation cost and time. However, discontinuity introduced by the sampling activity complicates the system dynamics and makes the stability analysis difficult compared with the pure continuous-time fuzzy control systems. Moreover, the favourable property of the continuous-time fuzzy control systems which is able to relax the stability analysis result vanishes in the sampled-data fuzzy control systems. A Lyapunov-based approach is employed to derive the LMI-based stability conditions to guarantee the system stability. To facilitate the stability analysis, a switching fuzzy model consisting of some local fuzzy models is employed to represent the nonlinear plant to be controlled. The comparatively less strong nonlinearity of each local fuzzy model eases the satisfaction of the stability conditions. Furthermore, membership functions of both fuzzy model and sampled-data fuzzy controller are considered to alleviate the conservativeness of the stability analysis result. A simulation example is given to illustrate the merits of the proposed approach.

"[Due to some interest in this topic, I have posted this paper to my website.  The paper was written as an assignment in a course in Dynamics and ODE's taught by Bjorn Sandstede at Ohio State University, and I do not intend to publish it.]



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In this paper, the economic structure of illegal markets with special reference to the markets for illegal drugs and arms is analyzed. Analytical tools of System Dynamics are employed to emphasize the dynamic aspects of these markets. The results of our analysis enable us to evaluate state intervention in the illegal markets for drugs and arms. It seems possible to mitigate the drugs problem by supplying drugs to heavily addicted people on the basis of health care measures. However, a similar policy seems not to exist for the illegal arms trade. This shows that each illegal market requires a deeper understanding before it can be fought effectively.

In Mexico, the Automotive Industry is one of the most important sectors, based on the amount of sales, as well as for the number of people employed. The level of competition facing firms to win OEM programs requires having a very strict control over the whole company's operation. System Dynamics is presented as a very powerful methodology for modeling the current and future situation of a company and combined with the Balanced scorecard concept, both provide a deep insight into the dynamics of the company. Based on this case of study a new methodology is proposed which provides a deeper insight on how the system works in such a way that the development of the company's strategy has greater impact. Through the simulation of 24 months into the future it is possible to understand the system´s behavior in terms of the interrelation of the most critical variables which were defined as the main KPI´s.

Heuristic knowledge has been integrated with analytical tools to support decision making for flood management. Development of an expert system called Intelligent Flood Management System for the selection of appropriate flood damage reduction measures for a given area is described. The selection of flood damage reduction measures is based on hydraulic, hydrological, geotechnical, environmental, and economic factors related to the river system and the area to be protected from floods. The knowledge base of the Intelligent Flood ...

In recent years, the growing population and the need to supply water for domestic, and health, and agriculture sectors have led to the establishment of industrial centers in developing countries. The onset of drought in most countries has challenged surface water, groundwater, dams, and reservoirs. Iran is among those countries, which is located in a dry and semi-arid region.  These factors made managers and decision-makers in this field make appropriate rules and regulations for the use of limited water resources. In this paper, the Vensim dynamic model was applied to properly exploit the Yamchi Dam water and groundwater resources in the Ardabil plain in Iran and allocate these resources in the agriculture, industry, and drinking sectors. By defining different scenarios, it was found that pressurized irrigation and changing the crop pattern scenarios are the most appropriate options for water management in the Yamchi basin. In this scenario, known as G in the model, 62% of the netw...

Health system performance management is a dynamically complex problem, affected by a large number of factors which interact to produce health outcomes over time. A brief review of current health system performance assessment instruments, including the balanced scorecard, demonstrates only a limited ability to deal with the dynamic complexity of this problem. These are limitations that can be overcome with

Kinematik bildet das vierte Kapitel zur Translationsmechanik des Lehrwerks Systemphysik für Fachhochschulen.  In der Einführungsphase werden Systeme mit einem systemdynamischen Tool (System Dynamics) modelliert, simuliert und validiert. Diese Methode fördert das saubere Analysieren und das strukturierte Denken. Nach einer intensiven Lern- und Erfahrungsphase werden die ausgereiften Modelle auf Modelica umgeschrieben und in einer speziell dafür geschriebenen Bibliothek hinterlegt.