Human resource requirements planning for nursing capacity has traditionally focused on expected utilization or demand and largely ignored the complex workplace policies. The approach taken in this research emphasizes the interaction of policies affecting compensation, work intensity, task satisfaction and career progression on hiring and retention the flows that determine the stock of nurses. Based on research conducted with Singapore Ministry of Health, we describe how policy changes influence employment levels at care venues over a strategic time horizon. To answer three research questions posed by experienced planners and managers, we employ a System Dynamics model to test and explain the implications of alternative policy choices.
A water cycle analysis System Dynamics model for designing an optimal reclaimed water production scheduling is proposed. A water cycle has various types of water flow and storage, so System Dynamics is suitable for modeling and simulating it. In addition, by using System Dynamics modeling software, various types of models for water cycle analysis can be modeled comparatively easily and used to design an optimal scheduling. The model must be able to analyze water quality and energies for water distribution and treatment as well as water flow and storage in order to schedule optimal production. It therefore consists of three components: water flow, water quality, and energy models. We constructed a water flow model that can handle various types of water flow. The Energy model computes the energy consumption of the pumps and blowers used in water distribution and water treatment systems, and the water quality model computes the water quality of treated wastewater and reclaimed water. Our constructed model was used to schedule water reclamation production to reduce the energy consumed during the water reclamation process and to ensure high quality of the reclaimed water. Simulation results showed that the proposed model is effective for designing an optimal scheduling.
Methods of systems analysis were applied to the illness multiple sclerosis (MS). By mapping causality among the many causes affecting multiple sclerosis, we have been able to show that it is a systemic illness, with multiple interacting causes and mechanisms. By using causal-loop diagrams we synthesized a systemic picture of MS in which the role of allergies, pathogens, molecular mimicry, venous vascular dynamics, membrane stability, immune system, and oxidants-antioxidant dynamics were integrated. There are important components that make up MS:
The TETRA-model has been built to predict the modern occurrence of ancient Athenian tetradrachm silver coins in quantitative terms, based on their original minting volumes an antiquity and the processes of their loss and destruction, as well as the process of finding them in modern times. The conceptual model was developed as causal loop diagrams and flow charts, based on Athenian siver mining dynamics, the minting process, the circulation in trade and finance in ancient Athens, rates of wear and loss of coinage, corrosion of coins in the buried state, modern retrieval rates and dynamic turnover in the numismatic market, as well as deposits into collections and museums. A systems dynamics model was programmed in the STELLA modeling environment and implemented for 500 years of Athenian coin production (526 BC to 42 AD) and preservation and retrieval until the present (526 BC to 2010 AD). The TETRA model was tested against independent estimates of past and present coin volumes, treasure finds, museum stocks. The model seems to work well in tests against independent estimates. The approximate number of coins surviving until today for the different types such as archaic owls, classical owls, transitional owls, heterogeneous owls and new style owls were predicted well within the estimates derived through other means and museum inventories (r2=0.82).
By using an integrated dynamic model we are able to reconstruct the supply and gold price of the past (1920-2010) and this is used to predict the future supply of gold to the market and to make a forecast of the gold price 2010-2100. The model was validated against field data for the period 1920-2010 and it performs well. The simulation results show that the market is fundamentally driven by supply and demand, but that derivates trade and speculations have affected the market significantly to create large short term variations in price. In the long term, the model predicts a shift from high-grade ores to low-grade deposits as the main supply source in the next 50 years, but that recycling will become the most important source of gold to the market. The authors predict a significant tightening of the gold market, with rising prices and a decreased derivates trade as compared to trade in the physical commodity. The model shows clearly that foreward and derivates trade create less stability and increase price fluctuations, but that they cannot prevent the long term trend from basic fundamental factors to set the long term levels.
Adaptation of SD mainly focuses on management and environment aspects, and successes to get enormous reputations from results. However, adaptation of SD is not limited on these areas, but disseminating to psychology and military science recently. Author believes such adaptation should be wider to other fields too. Continuous of such adaptation, this paper tries to build SD model for study literature with quantitative explanation and understanding. William Shakespeares Tragedy of Romeo and Juliet is one of best works in his early age. Similar story also looked in other literatures in other countries including works of Chikamatsu Monzaemon in Japan and opera Tristan and Isère. Added more, Romeo and Juliet was adapted to other forms of arts and literatures including Broadway musical West Side Story.