Dynamic systems as tools for analysing human judgement

With the advent of computers in the experimental labs, dynamic systems have become a new tool for research on problem solving and decision making. A short review on this research is given and the main features of these systems (connectivity and dynamics) are illustrated. To allow systematic approaches to the influential variables in this area, two formal frameworks (linear structural equations and finite state automata) are presented. Besides the formal background, it is shown how the task demands of system identification and system control can be realized in these environments and how psychometrically acceptable dependent variables can be derived

The L2L^2-torsion polytope of amenable groups

We introduce the notion of groups of polytope class and show that torsion-free amenable groups satisfying the Atiyah Conjecture possess this property. A direct consequence is the homotopy invariance of the $L^2$-torsion polytope among $G$-CW-complexes for these groups. As another application we prove that the $L^2$-torsion polytope of an amenable group vanishes provided that it contains a non-abelian elementary amenable normal subgroup.Comment: 21 page

The world trading system: Recent trends

Tariffs no longer represent the most serious impediment to international trade. As the importance of tariffs in restricting free trade has been declining, non-tariff barriers are becoming increasingly important. The use of selected non-tariff barriers is analyzed, focusing on anti-dumping measures, voluntary export restraints, trade related investment measures, and trade related intellectual property rights. Coming multilateral negotiations will have to concentrate on non-tariff barriers. A first prerequisite for successful negotiations is to increase transparency of these instruments. Only if transparency is ensured, improved enforcement mechanisms can be implemented.

Macroeconomic Shocks in Euroland vs. the UK: Supply, Demand, or Nominal?

currency; economic integration; EMU; Euro; European Central Bank; political economy; U.K.

Wage formation and monetary policy rules

This paper characterizes the wage setting behavior in a totally unionized economy under different monetary policy rules. The wage formation strategy of the union can be either aggressive or cooperative.. As long as the union is fully cooperative and in the absence of shocks, the government can completely reach its macroeconomic targets: full employment and price stability. If, however, the union becomes aggressive, a constant money supply rule has a nominal wage inflation bias under certain plausible- assumptions. By changing the rules of the game, e.g. following a nominal GNP or price level (inflation) rule, wage demands would be lower and the economy better off.

A new 3-D modelling method to extract subtransect dimensions from underwater videos

Underwater video transects have become a common tool for quantitative analysis of the seafloor. However a major difficulty remains in the accurate determination of the area surveyed as underwater navigation can be unreliable and image scaling does not always compensate for distortions due to perspective and topography. Depending on the camera set-up and available instruments, different methods of surface measurement are applied, which make it difficult to compare data obtained by different vehicles. 3-D modelling of the seafloor based on 2-D video data and a reference scale can be used to compute subtransect dimensions. Focussing on the length of the subtransect, the data obtained from 3-D models created with the software PhotoModeler Scanner are compared with those determined from underwater acoustic positioning (ultra short baseline, USBL) and bottom tracking (Doppler velocity log, DVL). 3-D model building and scaling was successfully conducted on all three tested set-ups and the distortion of the reference scales due to substrate roughness was identified as the main source of imprecision. Acoustic positioning was generally inaccurate and bottom tracking unreliable on rough terrain. Subtransect lengths assessed with PhotoModeler were on average 20 % longer than those derived from acoustic positioning due to the higher spatial resolution and the inclusion of slope. On a high relief wall bottom tracking and 3-D modelling yielded similar results. At present, 3-D modelling is the most powerful, albeit the most time-consuming, method for accurate determination of video subtransect dimensions

Mirror neuron activity is no proof for action understanding

We focus on the thesis that action understanding is a function of the mirror neuron system. According to our opinion, understanding is a process that runs through hermeneutic circles from the “Vorverständnis” (“previous understanding”) to steps of deeper understanding. Our critique relates to the narrow neuroscientific definition of action understanding as the capacity to recognize several movements as belonging to one action. After a reconstruction of the model's developments, we will challenge the claims of the model by Rizzolatti and Sinigaglia (2010). By analyzing the relation between the experimental results and its interpretation, we will conclude that there is no proof that mirror neuron activity leads to action understanding