The Stability of Dynamic Contests with Asymmetric and Endogenous Prizes

The paper develops a simple theoretical framework for analyzing repeated contests. At each stage of the infinitely repeated game, a Tullock contest is played by two players. We consider local stability of the Nash equilibrium with respect to adjustment speed and the level of the prize. The model is extended to an asymmetric valuation of the prize and to the case with an endogenous prize, where the level of the prize is influenced by the investments of the players.

Piracy of Digital Products: A Contest Theoretical Approach

In the following, we examine a market of a digital consumption good with monopolistic supply. In this market, it is the ability of the consumer to bypass (”crack”) the copy-protection of the monopolist which induces a lower price of the digital good, compared to an uncontested monopoly (textbook case). We analyze the complex relationship between the cracking efforts of the consumer, the copy-protection efforts and the pricing decision of the monopolist, and the welfare of the economy. We find, for example, that the monopolist will deter piracy if the (exogenous) relative effectiveness of the consumer’s bypassing activity is low compared to the copy-protection technology. In this case welfare is lower than the welfare in the textbook case. On the contrary, welfare rises above the textbook case level if the relative effectiveness of cracking is sufficiently high

Particle-in-Cell/Test-Particle Simulations of Technological Plasmas: Sputtering Transport in Capacitive Radio Frequency Discharges

The paper provides a tutorial to the conceptual layout of a self-consistently coupled Particle-In-Cell/Test-Particle model for the kinetic simulation of sputtering transport in capacitively coupled plasmas at low gas pressures. It explains when a kinetic approach is actually needed and which numerical concepts allow for the inherent nonequilibrium behavior of the charged and neutral particles. At the example of a generic sputtering discharge both the fundamentals of the applied Monte Carlo methods as well as the conceptual details in the context of the sputtering scenario are elaborated on. Finally, two in the context of sputtering transport simulations often exploited assumptions, namely on the energy distribution of impinging ions as well as on the test particle approach, are validated for the proposed example discharge

Contextual equivalence in lambda-calculi extended with letrec and with a parametric polymorphic type system

This paper describes a method to treat contextual equivalence in polymorphically typed lambda-calculi, and also how to transfer equivalences from the untyped versions of lambda-calculi to their typed variant, where our specific calculus has letrec, recursive types and is nondeterministic. An addition of a type label to every subexpression is all that is needed, together with some natural constraints for the consistency of the type labels and well-scopedness of expressions. One result is that an elementary but typed notion of program transformation is obtained and that untyped contextual equivalences also hold in the typed calculus as long as the expressions are well-typed. In order to have a nice interaction between reduction and typing, some reduction rules have to be accompanied with a type modification by generalizing or instantiating types

The spectral element method as an efficient tool for transient simulations of hydraulic systems

This paper presents transient numerical simulations of hydraulic systems in engineering applications using the spectral element method (SEM). Along with a detailed description of the underlying numerical method, it is shown that the SEM yields highly accurate numerical approximations at modest computational costs, which is in particular useful for optimization-based control applications. In order to enable fast explicit time stepping methods, the boundary conditions are imposed weakly using a numerically stable upwind discretization. The benefits of the SEM in the area of hydraulic system simulations are demonstrated in various examples including several simulations of strong water hammer effects. Due to its exceptional convergence characteristics, the SEM is particularly well suited to be used in real-time capable control applications. As an example, it is shown that the time evolution of pressure waves in a large scale pumped-storage power plant can be well approximated using a low-dimensional system representation utilizing a minimum number of dynamical states

Interwire coupling for In(4x1) /Si(111) probed by surface transport

The In/Si(111) system reveals an anisotropy in the electrical conductivity and is a prototype system for atomic wires on surfaces. We use this system to study and tune the interwire interaction by adsorption of oxygen. Through rotational square four-tip transport measurements, both the parallel (σ||) and perpendicular (σ⊥) components are measured separately. The analysis of the I(V) curves reveals that σ⊥ is also affected by adsorption of oxygen, showing clearly an effective interwire coupling, in agreement with density-functional-theory-based calculations of the transmittance. In addition to these surface-state mediated transport channels, we confirm the existence of conducting parasitic space-charge layer channels and address the importance of substrate steps by performing the transport measurements of In phases grown on Si(111) mesa structures.DFG/FOR/170