Using Genetics Based Machine Learning to find Strategies for Product Placement in a dynamic Market

In this paper we discuss the necessity of models including complex adaptive systems in order to eliminate the shortcomings of neoclassical models based on equilibrium theory. A simulation model containing artificial adaptive agents is used to explore the dynamics of a market of highly replaceable products. A population consisting of two classes of agents is implemented to observe if methods provided by modern computational intelligence can help finding a meaningful strategy for product placement. During several simulation runs it turned out that the agents using CI-methods outperformed their competitors.product positioning; market simulation; heterogeneous agents; learning classifier systems; genetic algorithms; adaptive systems modelling

Adaptive agents in the House of Quality

Managing the information flow within a big organization is a challenging task. Moreover, in a distributed decision-making process conflicting objectives occur. In this paper, artificial adaptive agents are used to analyze this problem. The decision makers are implemented as Classifier Systems, and their learning process is simulated by Genetic Algorithms. To validate the outcomes we compared the results with the optimal solutions obtained by full enumeration. It turned out that the genetic algorithm indeed was able to generate useful rules that describe how the decision makers involved in new product development should react to the requests they are required to fulfill.new product development; total quality management; quality function deployment; information flow; organisational learning; learning classifier systems; genetic algorithms

Family Policies in the Context of Low Fertility and Social Structure.

The aim of this paper is to analyse the effectivity of family policies in the context of different assumptions regarding the social structure of a society. We use an agent based simulation model to analyse the impact of family policies on individual fertility decisions and on cohort fertility, intended fertility, and the fertility gap on the aggregate level. The crucial features of our simulation model are the agents' heterogeneity with respect to age, income, parity, and intended fertility, the social network and social influence. Our results indicate that both fixed and income dependent child supports have a positive and significant impact on fertility. However, several network and social influence parameters have the ability not only to influence fertility itself but also the effectivity of family policies. Therefore, policymakers aiming to transfer a certain policy mix that has proved successful from one country to another one ignoring differences in the social structure may fail. Family policies can only be successful if they explicitly take into account the characteristics of the society they are assigned for.Family policies, low fertility, social influence, social networks, social structure.

Decomposing the change in labour force indicators over time

In this paper we study changes in the size and the composition of the labour force in five OECD countries from 1983 through 2000. We apply a recent decomposition method to quantify the components of the change over time in the crude labour force rate and the mean age of the labour force. Our results show that the change in the crude labour force rate was dominated by the change in age-specific labour force participation rates. For the mean age of the labour force we find that for males the change in the age composition of the population predominately explains the overall change while the results for females are less clear-cut.decomposition method, labor force, labor force indicators, population aging

The "Wedding-Ring"

In this paper we develop an agent-based marriage model based on social interaction. We build an population of interacting agents whose chances of marrying depend on the availability of partners, and whose willingness to marry depends on the share of relevant others in their social network who are already married. We then let the typical aggregate age pattern of marriage emerge from the bottom-up. The results of our simulation show that micro-level hypotheses founded on existing theory and evidence on social interaction can reproduce age-at-marriage patterns with both realistic shape and realistic micro-level dynamics.age at marriage, agent-based computational demography, marriage, micro-macro, models, social interaction

Workshop on "Agent-Based Computational Modelling. An Instrument for Analysing Complex Adaptive Systems in Demography, Economics and Environment" at the Vienna Institute of Demography, December 4-6, 2003

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Projections of the Development of Population and Employment in Austria until 2035

This paper investigates the future development of the Austrian population for the period from 2005 to 2035. The main focus of our investigation lies on the working age population and its age structure. Our calculations are based on the population projection released by Statistik Austria in 2005. We present three different scenarios with respect to age specific labour force participation rates and discuss their impact on the Austrian labour force. We show that both the main variant and the low migration variant of the population projection allow for an annual increase in the total size of labour force of 0.3% until the end of our observation period by applying labour force participation rates which are already put into practice in the Nordic countries. An increase in labour force participation rates does not only help to maintain an increase in the labour force but also leads to a more homogenous age distribution of the labour force.ageing; age structure; labour force; labour force participation rates

Collective Social Dynamics and Social Norms

How individual behaviour is determined or at least influenced by social norms is one of the classic questions of social theory. We consider a norm as a rule guiding individual decisions concerning rituals, beliefs, traditions, and routines. Whenever coordinated behaviour is enforced without the help of an authority, this may be due to social norms. The individual being in the situation of taking a decision at the micro level is guided by social norms imposed at the macro level. The set of all individual decisions in a society generates the macro level behaviour of the system which may strengthen or weaken the existing social norms. Thus, the long run development of social norms is the result of collective dynamics within a social network. We use an agent based simulation model to investigate the emergence, stability, and replacement of social norms within a population of artificial agents. A social network connecting the agents serves to communicate the social norms and the actual behaviour among the agent population. The agents in the network possess two types of links connecting them with their ingroup and with their outgroup, respectively. Agents have the desire to be associated and accepted by the members of their ingroup and they want to be different from the members of their outgroup. Consequently, they derive a utility from adhering to the social norm of their ingroup and from deviating from the social norm of their outgroup. Agents may adopt their behaviour according to the norms given by their ingroup and outgroup. Thus, our model explains under what conditions social norms prevail within a subgroup of the society or even become global norms being respected within the whole population

The Ultraviolet Filter 3-Benzylidene Camphor Adversely Affects Reproduction in Fathead Minnow (Pimephales promelas)

The ultraviolet (UV) filter 3-benzylidene camphor (3BC) is used in personal care products and in a number of materials for UV protection. 3BC has been shown in vitro and in vivo in fish to be estrogenic, but possible effects on fertility and reproduction are unknown. In this study we evaluate whether 3BC affects reproduction of fish Pimephales promelas. After a preexposure period of 21 days, reproductively mature fathead minnows were exposed to increasing concentrations of 3BC for 21 days in a static-renewal procedure. Actual 3BC concentrations decreased to 23% of initial levels and median concentrations were 0.5, 3, 33, 74, and 285 μg/l. 3BC affected reproduction in a dose-dependent manner with weak effects on fecundity at 3 μg/l, a significant decrease at 74 μg/l, and a cessation of reproduction at 285 μg/l. 3BC was accumulated in fish with an average bioconcentration factor of 313 ± 151. Dose-dependent demasculinization in secondary sex characteristics of male fish and dose-dependent induction of plasma vitellogenin occurred, which was significant at 74 μg/l and higher. 3BC had a profound and dose-dependent effect on the histology of gonads of male and female fish at 3 μg/l and higher. At 74 and 285 μg/l, oocyte and spermatocyte development was inhibited in male and female gonads. Testes of exposed males had much fewer spermatogenic cysts, and ovaries of exposed females had much fewer mature but more atretic, follicles. This study shows significant effects of the UV filter 3BC on fertility, gonadal development, and reproduction of fish after short-term exposure that may have negative consequences on the population leve