MaLeS: A Framework for Automatic Tuning of Automated Theorem Provers

MaLeS is an automatic tuning framework for automated theorem provers. It provides solutions for both the strategy finding as well as the strategy scheduling problem. This paper describes the tool and the methods used in it, and evaluates its performance on three automated theorem provers: E, LEO-II and Satallax. An evaluation on a subset of the TPTP library problems shows that on average a MaLeS-tuned prover solves 8.67% more problems than the prover with its default settings

Atomic defects and dopants in ternary Z-phase transition-metal nitrides CrMN with M=V, Nb, Ta investigated with density functional theory

A density functional theory study of atomic defects and dopants in ternary Z-phase transition-metal nitrides CrMN with M=V, Nb, or Ta is presented. Various defect formation energies of native point defects and of substitutional atoms of other metal elements which are abundant in the steel as well, are evaluated. The dependence thereof on the thermodynamic environment, i.e. the chemical conditions of a growing Z-phase precipitate, is studied and different growth scenarios are compared. The results obtained may help to relate results of experimental atomic-scale analysis, by atom probe tomography or transmission electron microscopy, to the theoretical modeling of the formation process of the Z phase from binary transition metal nitrides

Coulomb-interaction effects in full counting statistics of a quantum-dot Aharonov-Bohm interferometer

We study the effect of Coulomb interaction on the full counting statistics of an Aharonov-Bohm (AB) interferometer with a single-level quantum dot in one arm in the regime of weak dot-lead and lead-lead tunnel couplings. In the absence of Coulomb interaction, the interference processes are of nonresonant nature with an even AB flux dependence and obey bidirectional Poissonian statistics. For large charging energy, the statistic of these processes changes. In addition, processes of resonant nature with an odd flux dependence appear. In the limit of strongly asymmetric tunnel couplings from the dot to the left and right leads, their statistics is found to be strongly super-Poissonian.Comment: 8 pages, 3 figure

National Multi-Modal Travel Forecasts. Literature Review: Aggregate Models

This paper reviews the current state-of-the-art in the production of National Multi-Modal Travel Forecasts. The review concentrates on the UK travel market and the various attempts to produce a set of accurate, coherent and credible forecasts. The paper starts by a brief introduction to the topic area. The second section gives a description of the background to the process and the problems involved in producing forecasts. Much of the material and terminology in the section, which covers modelling methodologies, is from Ortúzar and Willumsen (1994). The paper then goes on to review the forecasting methodology used by the Department of Transport (DoT) to produce the periodic National Road Traffic Forecasts (NRTF), which are the most significant set of travel forecasts in the UK. A brief explanation of the methodology will be given. The next section contains details of how other individuals and organisations have used, commented on or attempted to enhance the DoT methodology and forecasts. It will be noted that the DoT forecasts are only concerned with road traffic forecasts, with other modes (rail, air and sea) only impacting on these forecasts when there is a transfer to or from the road transport sector. So the following sections explore the attempts to produce explicit travel and transportation forecasts for these other modes. The final section gathers together a set of issues which are raised by this review and might be considered by the project

Rashba spin-orbit interaction in graphene armchair nanoribbons

We study graphene nanoribbons (GNRs) with armchair edges in the presence of Rashba spin-orbit interaction (RSOI). We impose the boundary conditions on the tight binding Hamiltonians for bulk graphene with RSOI by means of a sine transform and study in detail the influence of RSOI on the spectra and the spin polarization. We show that the spin polarization perpendicular to the GNR changes sign when reversing the momentum along the GNR if the bands are coupled by strong RSOI. Furthermore, we derive a linearized approximation to the RSOI Hamiltonian and find that only the neighboring modes of an energy band have to be taken into account in order to achieve a good approximation for the same band. Due to their experimental availability and various proposals for engineering appropriate RSOI, GNRs with armchair edges are a promising candidate for possible spintronics applications.Comment: added journal reference, small updates, 9 pages, 8 figure

Working Paper No. 62, Uses of Abduction in Economic Science

This inquiry considers the meaning of abduction and its uses in Economic Science. Abductive logic is discussed at some length, in order to clarify how it is used in this inquiry. In addition, abduction is traced from its appearances in the writings of pragmatist philosopher Charles Sanders Peirce and how its meaning is later carried on in Thorstein Veblen’s Institutional Economics. Peirce’s influence proves foundational for Veblen’s contributions, as well as for the writings of John Roger Commons. My research suggests that after Commons, Peirce’s influence in economics wanes. Additionally, the use of retroduction in critical realism provides a contemporary example of abduction. This inquiry concludes by discussing implications of abductive logic, suggesting that abduction proves essential for the advancement of Economic Science