7,604 research outputs found
Dimensional reduction and the equivariant Chern character
We propose a dimensional reduction procedure in the Stolz--Teichner framework
of supersymmetric Euclidean field theories (EFTs) that is well-suited in the
presence of a finite gauge group or, more generally, for field theories over an
orbifold. As an illustration, we give a geometric interpretation of the Chern
character for manifolds with an action by a finite group.Comment: 29 pages. Exposition improvements and expanded appendix
Convergence behaviour of structural FSM traversal
We present a theoretical analysis of structural FSM traversal, which is the basis for the sequential equivalence checking algorithm Record & Play presented earlier. We compare the convergence behaviour of exact and approximative structural FSM traversal with that of standard BDD-based FSM traversal. We show that for most circuits encountered in practice exact structural FSM traversal reaches the fixed point as fast as symbolic FSM traversal, while approximation can significantly reduce in the number of iterations needed. Our experiments confirm these results
Verification of integer multipliers on the arithmetic bit level
One of the most severe short-comings of currently available equivalence checkers is their inability to verify integer multipliers. In this paper, we present a bit level reverse-engineering technique that can be integrated into standard equivalence checking flows. We propose a Boolean mapping algorithm that extracts a network of half adders from the gate netlist of an addition circuit. Once the arithmetic bit level representation of the circuit is obtained, equivalence checking can be performed using simple arithmetic operations. Experimental results show the promise of our approach
Ground-state Properties of a Supersolid in RPA
We investigate the newly discovered supersolid phase by solving in
random-phase approximation the anisotropic Heisenberg model of the hard-core
boson He lattice at zero temperature. We include nearest and next-nearest
neighbor interactions and calculate exactly all pair correlation functions in a
cumulant decoupling scheme. We demonstrate the importance of vacancies and
interstitials in the formation of the supersolid phase. The supersolid phase is
characterised by strong quantum fluctuations which are taken into account
rigorously. Furthermore we confirm that the superfluid to supersolid transition
is triggered by a collapsing roton minimum however is stable against
spontaneously induced superflow, i.e. vortex creation.Comment: 10 pages, 8 figure
Accelerating Boolean implications with FPGAs
We present the FPGA implementation of an algorithm [4] that computes implications between signal values in a boolean network. The research was performed as a masterrsquos thesis [5] at the University of Frankfurt. The recursive algorithm is rather complex for a hardware realization and therefore the FPGA implementation is an interesting example for the potential of reconfigurable computing beyond systolic algorithms. A circuit generator was written that transforms a boolean network into a network of small processing elements and a global control logic which together implement the algorithm. The resulting circuit performs the computation two orders of magnitudes faster than a software implementation run by a conventional workstation
Pierre Duhem’s philosophy and history of science
LEITE (Fábio Rodrigo) – STOFFEL (Jean-François), Introduction (pp. 3-6). BARRA (Eduardo Salles de O.) – SANTOS (Ricardo Batista dos), Duhem’s analysis of Newtonian method and the logical priority of physics over metaphysics (pp. 7-19). BORDONI (Stefano), The French roots of Duhem’s early historiography and epistemology (pp. 20-35). CHIAPPIN (José R. N.) – LARANJEIRAS (Cássio Costa), Duhem’s critical analysis of mechanicism and his defense of a formal conception of theoretical physics (pp. 36-53). GUEGUEN (Marie) – PSILLOS (Stathis), Anti-scepticism and epistemic humility in Pierre Duhem’s philosophy of science (pp. 54-72). LISTON (Michael), Duhem : images of science, historical continuity, and the first crisis in physics (pp. 73-84). MAIOCCHI (Roberto), Duhem in pre-war Italian philosophy : the reasons of an absence (pp. 85-92). HERNÁNDEZ MÁRQUEZ (Víctor Manuel), Was Pierre Duhem an «esprit de finesse» ? (pp. 93-107). NEEDHAM (Paul), Was Duhem justified in not distinguishing between physical and chemical atomism ? (pp. 108-111). OLGUIN (Roberto Estrada), «Bon sens» and «noûs» (pp. 112-126). OLIVEIRA (Amelia J.), Duhem’s legacy for the change in the historiography of science : An analysis based on Kuhn’s writings (pp. 127-139). PRÍNCIPE (João), Poincaré and Duhem : Resonances in their first epistemological reflections (pp. 140-156). MONDRAGON (Damián Islas), Book review of «Pierre Duhem : entre física y metafísica» (pp. 157-159). STOFFEL (Jean-François), Book review of P. Duhem : «La théorie physique : son objet, sa structure» / edit. by S. Roux (pp. 160-162). STOFFEL (Jean-François), Book review of St. Bordoni : «When historiography met epistemology» (pp. 163-165)
Effect of a surface tension imbalance on a partly submerged cylinder
We perform a static analysis of a circular cylinder that forms a barrier
between surfactant-laden and surfactant-free portions of a liquidgas
interface. In addition to determining the general implications of the balances
for forces and torques, we quantify how the imbalance
between the uniform surface tension
of the surfactant-free portion of the interface and the uniform surface tension
of the surfactant-laden portion of the interface influences the
load-bearing capacity of a hydrophobic cylinder. Moreover, we demonstrate that
the difference between surface tensions on either side of a cylinder with a
cross-section of arbitrary shape induces a horizontal force component
equal to in magnitude, when measured per unit length of the
cylinder. With an energetic argument, we show that this relation also applies
to rod-like barriers with cross-sections of variable shape. In addition, we
apply our analysis to amphiphilic Janus cylinders and we discuss practical
implications of our findings for Marangoni propulsion and surface pressure
measurements
Cell replication and redundancy elimination during placement for cycle time optimization
This paper presents a new timing driven approach for cell replication tailored to the practical needs of standard cell layout design. Cell replication methods have been studied extensively in the context of generic partitioning problems. However, until now it has remained unclear what practical benefit can be obtained from this concept in a realistic environment for timing driven layout synthesis. Therefore, this paper presents a timing driven cell replication procedure, demonstrates its incorporation into a standard cell placement and routing tool and examines its benefit on the final circuit performance in comparison with conventional gate or transistor sizing techniques. Furthermore, we demonstrate that cell replication can deteriorate the stuck-at fault testability of circuits and show that stuck-at redundancy elimination must be integrated into the placement procedure. Experimental results demonstrate the usefulness of the proposed methodology and suggest that cell replication should be an integral part of the physical design flow complementing traditional gate sizing techniques
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