We developed a feedback model for the control of the angular position of a model helicopter that has a single main rotor and single tail rotor. Basically, there are two mechanisms involved in the control of angular position in the horizontal plane; the torque resulting from the rotation of the main rotor and the opposite direction torque created by the tail rotor. For the purpose of this study, the rotational speed of the main rotor is kept constant. The angular position is solely controlled through the change in the tail rotors rotational speed. Tail rotors rotational speed determines the net torque on the fuselage; the net torque determines the angular acceleration; the angular acceleration changes the angular velocity; the angular velocity changes the angular position. Therefore, the angular position of the fuselage is indirectly controlled by the tail rotors rotational speed. The delay introduced by the indirect control process makes it difficult to control the angular position of the model helicopter. After modeling the physical structure of the model helicopter, we simulated it with two different decision making heuristics. The Modified-VSL heuristic that is introduced in this paper performs much better than the simple naive heuristic.
Efforts to increase forest cover in the developing world will only succeed if the root causes of deforestation are addressed. Researchers designing reforestation initiatives tend to emphasize macro-level drivers of deforestation, such as population growth and federal policy. On the other hand, local people have knowledge of social and cultural dynamics that may be critical in the successful implementation of reforestation efforts. The perception gap between researchers and community members has led to many failed or insufficiently implemented projects. An emerging toolgroup model building with system dynamicsshows promise in its ability to integrate different perspectives on a complex problem such as forest cover loss. In this study, I use system dynamics modeling methodology to compare causal loop diagrams of forest cover dynamics on Negros Island, Philippines generated by researchers working for the World Wildlife Fund with causal loop diagrams generated by community members in upland Negros. The diagrams were significantly different, with very few variables in common, but both illuminate critical aspects of the deforestation problem on the island. I conclude that reforestation initiatives in the Philippines would benefit from incorporating all relevant information into a single, coherent model.
The comparison of mental models of dynamical systems can help understanding they way individuals understand dynamic situations and how their understanding changes. Current approaches like the Distance Ratio and the Closeness Ratio have been criticized for not taking into account feedback loops and delays; an improved comparison method has been proposed, specifying an Element Distance Ratio, Loop Distance Ratios and a Model Distance Ratio. We are advancing in the automation of the computations in order to take this burden away from analysts. This paper describes the essential computations. It briefly presents the comparison method for the different ratios. Then it introduces the conceptual architecture of the software tool, its main data structures and algorithms. The tool shall be put to use in mental model research.
System dynamics is progressively taught in different levels of education systems. There are challenges as for integrating it into the curricula of different professions and at the same time striving to grow it into a profession on its own. This paper starts recognizing that no representation of what is learned in system dynamics has been published in a way compatible with mainstream curricular tools. Specifically the need to integrate system dynamics into a competency-based curriculum has lead to a search in the field. We have opted for Blooms taxonomy as a widely shared reference frame and thus have expressed cognitive resources and development indicators in Blooms terms. The result is now a valuable resource for incorporating elements of system dynamics across different courses of undergraduate programmes in our university. Even so, the result has to be critically revised, for there are several open questions concerning the development stages of the learning process and the best form of representing them in order to facilitate the design and development of learning and assessment activities.
EP industry is expected to play a central role in climate change mitigation in many countries. With its rich clean energy potential, Turkey is a particular example. Being a developing economy, Turkey contributes to about one percent of global GHG emissions, and its per capita emissions are equal to and now exceeding the world average. The EP industry in Turkey is responsible for 28 percent of the national CO2 emissions. If a viable and sustainable global climate treaty develops in the near future, as a party to the UNFCCC, Turkey will have to assume national abatement targets and face the challenge of shifting its heavily fossil fuel based EP production towards renewable energy sources (RES), decentralized generation (DG) and increasing efficiency gains. In this paper, we create a dynamic simulation model of EP industry in Turkey so as to analyze the options for CO2 mitigation through replacements with cleaner energy resources. The model focuses on the supply side of EP sector and represents the investment, production, pricing and financing structures of coal, gas, hydro, wind and solar power plants as well as the existing natural potential for the renewable resources.
Outlined is the systems based process used to investigate delayed discharging, which combines parts of the Soft Systems Methodology (SSM) with Systems Dynamics (SD).At the early stages use of hard system approaches were inappropriate to investigate this type of complex problem. SSM was used to consider the soft problems present, expressing the problem situation as a rich picture. This informed construction of a SD model to investigate policy interventions for reducing delayed discharges. This process had practical implications for structuring qualitative data to inform the SD methodology.
Delayed discharges have become a common problem within hospital, predominately within elderly care. Patients become blocked unnecessarily along the patient pathway. Historically allocation system policies were needed acting as coping mechanisms when there was a lack of social workers to carry out patient assessments and set up services. These allocation policies helped to reduce delayed discharging of elderly patients when resources were scarce.
For many decades, Korean shipbuilders have been the leader of the global market. They offer cost effective and high quality vessels based on their advanced production technologies, good management and process control which helps them utilize their economies of scale and learning effect. Korean shipbuilders top the industry with highest market share.