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We discuss the use of Agent-based Modelling for the development and testing of theories about emergent social phenomena in marketing and the social sciences in general. We address both theoretical aspects about the types of phenomena that are suitably addressed with this approach and practical guidelines to help plan and structure the development of a theory about the causes of such a phenomenon in conjunction with a matching ABM. We argue that research about complex social phenomena is still largely fundamental research and therefore an iterative and cyclical development process of both theory and model is to be expected. To better anticipate and manage this process, we provide theoretical and practical guidelines. These may help to identify and structure the domain of candidate explanations for a social phenomenon, and furthermore assist the process of model implementation and subsequent development. The main goal of this paper was to make research on complex social systems more accessible and help anticipate and structure the research process.

With the introduction of the European emissions legislation for particle number and particle mass (Euro 6c stage), particulate emissions are currently a core issue in the development of Gasoline Direct Injection (GDI) engines. Due to the different mixing process of fuel and air GDI engines emit more particulates than engines with port fuel injection.The present development aims at the reduction of particulate emissions through exhaust gas aftertreatment, e.g. via gasoline particle filters (GPF). To minimize the technical complexity in the aftertreatment system the control of the burn-out of particulates within GPF has an enormous significance. The regeneration behavior of GPF is essentially dependent on the reactivity of the stored soot and its properties that in turn depend on the engine operation conditions. The main objective is the enhancement and control of the reactivity of the emitted soot particles by engine parameters. The basic studies were carried out on a turbocharged 4-cylinder engine with direct injection by varying the engine operating parameters, e.g. engine speed, air fuel ratio, injection timing. The particles are investigated in terms of their reactivity, number and size distribution and microstructure by using thermogravimetric analysis (TGA-FTIR), engine exhaust particle sizer (EEPS) and high-resolution transmission electron microscopy (HR-TEM). The investigations show a direct and indirect impact of engine operation parameters on the soot reactivity and its properties. The results of the parameter variations showed that the reactivity of particles can be controlled and enhanced by the operation conditions of the engine. To maximize the soot reactivity further investigations must be ...