The main aim of this paper is to study the impact on birth rate of specific public policies: subsidies to chilbearing and public consumption. The analysis is framed in an developed economy in which fertility choices and economic decisions are interconnected. In particular, the study relies on overlapping generations, habit formation in consumption and endogenous fertility rate. This last factor is directly explained by the preference for children, the economic capacity of young people and the stylized fact of unemployment. The outcome is a versatile system dynamics model that is adapted for the Portuguese economy from 2000 to 2011. Two counterfactual exercises differentiated from the employment distribution but with identical alternatives of public spending are implemented in the simulation model. The results show two divergent aspects: the births do not vary if the public consumption increases but, the births increase when the costs of childrearing are subsidized even if the public consumption is high. These results also indicate that the subsidies are not sufficient to curb the decreasing trend of births. In addition to them, it is required a sustainable economic growth.
In the last decades in several mature democracies the problem of debt emerged as a violation of intergenerational equal treatment due to high expenditures concentration and dilution of costs by mean of debt creation. So far this issue has been analyzed from a statistical and a socio-economic perspective, which identified the high political interference as the main dysfunction of country debt management. There are no studies which frame the issue by focusing on State institutions as performance-oriented organizations, according to this perspective such organizations have to respect dynamically trade-off between development and the debt reduction through a mix of levers such as: funds acquisition/reduction, interest rate and financial leverage. System dynamics can be successfully used as an instrument to support Government in keeping control over the key variables affecting debt changes and implementing a sustainable policy. In the paper three kinds of policies are recommended: the reduction of expenses and increase of receipts in the short term to drastically reduce the debt amount; the opportunity to exploit the financial leverage in the long term. Such approach implies a change of perspective, looking at Italy as a performance-oriented organization in which a proper financial management serves economic development and not vice versa.
World Class Manufacturing (WCM) has attracted the attention of many manufacturing industries and operation strategists. Lack of clarification of relationships among widely spreading elements of manufacturing process and poor attention to non-linearity and time delays, all are the main reasons that some companies may be far away from developing a comprehensive and advantageous model in a WCM system. The purpose of this paper is designing and analysis a dynamic Model of WCM system to develop a proper strategy which changing the current situation into a WCM situation would be possible in the future By the Dynamic Balanced scorecard (DBSC) methodology as well as clarifying deficiencies of classical balanced scorecard, a systematic model of WCM has been presented through causal loop and stock & flow diagrams. This research has been carried out as a case study in the Iran Khodro Co.(IKCO), We've used Vensim software for designing and analyzing our model after entering related data, parameters, and equations. Some strategies have been presented through analyzing the scenario and running the simulation model.
The formation of the EU is the one of the biggest politicaleconomic events of the last 50 years. EU development process is still incomplete, with still evolving EU economic foundations and financial system. The aim of study is to develop EU economy functioning SD model, taking into account main economic indicator changes of EU countries since EU enlargement. Study result author divides countries into several groups, based on their economic specifics. For these groups in the paper the first attempt to develop EU economy system dynamic model is undertaken. General scheme of EU economy SD model is shown, new EU member economic integration model is developed. Model is tested only for one EU country, Latvia. Results of paper show failure of mechanism of EU operations. The available mechanism contradicts EU principles; it doesn't promote the cohesion in EU, but quite opposite- leads to solving problems of well-developed EU countries at the expense of developing countries. In the given conditions the example of Latvia shows that there is no possibility to overcome the system crisis. These circumstances specify necessity of changes in EU internal migratory policy, in principles of developing countries support, in distribution of means, taking into account internal migration.
GEPSUS, decision support system for handling hazardous air pollutant releases was developed based on a Gaussian simulation model of air pollution dispersion using MATLAB. For the Gaussian model the following assumptions apply: a) the smokestack emission is constant and continuous, b) flat homogeneous terrain, and c) the wind speed is constant. It is assumed that in the main wind direction, x, advection dominates over diffusion and dispersion. A detailed outline of the system integration is provided, which includes aspects of hydro-meteorological data, eco-toxicological data, Geographical Information Systems (GIS), user input, and system output including a description of threat zones and evacuation plans using a geo-browser. The Gaussian air-pollution dispersion simulation model is linked to the GIS by generating the output in KML file format. Several simulation scenarios were considered using meteorological data sets of wind speed, wind direction and ambient temperature. The developed simulation model and decision support system is intended to facilitate rapid emergency response for both deliberate and accidental air pollution releases. System dynamics model is developed to address the crisis mitigation issues.
In this paper we model the impacts of competition between cities when considering demand management strategies on both the optimal tolls and business and residential location choices. The work builds on earlier work which studied competition in a small network using a static equilibrium approach. That work showed that while both cities have an incentive to charge alone, once they begin, they are likely to fall into a Nash trap or prisoners dilemma where both cities are worse off. Our research extends this by setting up a system dynamics model which includes all modes and longer term location responses. The model is used first to study an isolated city and a simplified welfare function is used to determine the optimal toll around the central area and its impacts on location decisions and other transport indicators. A twin city is then added. Traffic from the neighbouring city may be charged and the revenue retained - a form of tax exporting behaviour which should increase the welfare of the city. We study the impact on the optimal tolls set by the cities and how the game develops between cities of equal size and amenity. The impact on location decisions and other transport indicators are presented along-side the implications for regulation and the development of cities within regional partnerships.
This paper presents a dynamic simulation model for the study of the residential heat market in Germany with regard to the European energy targets for the year 2020. It describes the model properties and specifies the dynamic structures of the demand side based on housing units and of the supply side which is formed by heating systems. An initial model validation indicates the appropriateness of the model assumptions. Five policy scenarios are introduced which take into account different measures for the promotion of renewable and innovative heat generation technologies and obligations for energy-efficient renovation of buildings. The discussion of the scenarios shows that with the given set of policies, the EU targets for heat demand reduction and CO2 emission mitigation in the residential sector would not be met, while the envisaged share of renewable and innovative technologies seems to be achievable.
Successful corporate action requires a comprehensive recognition of the relevant cause-effect relationships. In combination with the mental models of decision-makers, and as a complement to static instruments for business management, system dynamics simulation models provide valuable support. However, due to the usually experienced big effort and the demand of specific modelling knowledge the use of such models is not yet widespread within management. In order to give medium-sized companies in particular access to such simulation models, a practice-oriented concept was developed, enabling the design and implementation of system dynamics models as to support decision-making within strategic management. Within the framework of an empirical case-study, simulation models were developed for and implemented in four production companies. In order to make the modelling process as simple, efficient, effective and relevant as possible, a practical procedure was derived out of the case studies. This procedure describes the entire modelling process encompassing the initial process of structuring the mental models, the development of quantitative simulation models, as well as the analysis of various scenarios. The concept is based on generic model components, assembled to form a fundamental model structure (backbone) in order to facilitate and to accelerate the modelling process.