Domain-Type-Guided Refinement Selection Based on Sliced Path Prefixes

Abstraction is a successful technique in software verification, and interpolation on infeasible error paths is a successful approach to automatically detect the right level of abstraction in counterexample-guided abstraction refinement. Because the interpolants have a significant influence on the quality of the abstraction, and thus, the effectiveness of the verification, an algorithm for deriving the best possible interpolants is desirable. We present an analysis-independent technique that makes it possible to extract several alternative sequences of interpolants from one given infeasible error path, if there are several reasons for infeasibility in the error path. We take as input the given infeasible error path and apply a slicing technique to obtain a set of error paths that are more abstract than the original error path but still infeasible, each for a different reason. The (more abstract) constraints of the new paths can be passed to a standard interpolation engine, in order to obtain a set of interpolant sequences, one for each new path. The analysis can then choose from this set of interpolant sequences and select the most appropriate, instead of being bound to the single interpolant sequence that the interpolation engine would normally return. For example, we can select based on domain types of variables in the interpolants, prefer to avoid loop counters, or compare with templates for potential loop invariants, and thus control what kind of information occurs in the abstraction of the program. We implemented the new algorithm in the open-source verification framework CPAchecker and show that our proof-technique-independent approach yields a significant improvement of the effectiveness and efficiency of the verification process.Comment: 10 pages, 5 figures, 1 table, 4 algorithm

Quark Structure and Weak Decays of Heavy Mesons

We investigate the quark structure of D and B mesons in the framework of a constituent quark model. To this end, we assume a scalar confining and a one gluon exchange (OGE) potential. The parameters of the model are adopted to reproduce the meson mass spectrum. From a fit to ARGUS and CLEO data on B->D*lv semileptonic decay we find for the Cabbibo Kobayashi Maskawa matrix element Vcb=0.036+-0.003. We compare our form factors to the pole dominance hypothesis and the heavy quark limit. For non-leptonic decays we utilize factorization and for B->D*X decays we find a1 = 0.96+-0.05, and a2=0.31+-0.03.Comment: LATEX, 26 pages, 12 tables, 6 figures (appended as uuencoded file but also available as postscript files from the authors), BONN TK-93-1

Goethean rhymes and rhythms in verse translations of Faust into Spanish

The few translators who have attempted a Spanish verse translation of Goethe’s Faust for the most part fail to do justice to the metrical diversity of Goethe’s play and therefore they either altogether give up the idea of rendering Goethe’s play in poetry, e.g. Pedro Gálvez in 1984, or they create a traditionalist Spanish Faust poem with excessive liberties regarding its content, like, in 1882, Teodoro Llorente. Others have tried to fit Goethe’s verse in the Procrustean bed of unrhymed endecasílabos, which has forced them to abridge the original text in numerous passages (Valverde 1963). Moreover, some authors, such as Valverde and Silvetti Paz (1970), translate some passages of Goethe’s magnum opus into Spanish verses resembling unrhymed iambic pentameter, a rather unusual approach in Spanish poetry, but nevertheless surprisingly effective. The translation which clearly stands out is the one by Augusto Bunge (1926, 1949), who carefully studied and analyzed the metrical structure of Faust and created a Spanish version which imitates Goethe’s complex rhythms and rhyme patterns while remaining largely faithful to the German original.This article is the English version of “Los ritmos y la rima de la versificación goetheana en las versiones métricas del Fausto en español” by Stefan Beyer. It was not published on the print version of MonTI for reasons of space. The online version of MonTI does not suffer from these limitations, and this is our way of promoting plurilingualism

Towards a Principled Integration of Multi-Camera Re-Identification and Tracking through Optimal Bayes Filters

With the rise of end-to-end learning through deep learning, person detectors and re-identification (ReID) models have recently become very strong. Multi-camera multi-target (MCMT) tracking has not fully gone through this transformation yet. We intend to take another step in this direction by presenting a theoretically principled way of integrating ReID with tracking formulated as an optimal Bayes filter. This conveniently side-steps the need for data-association and opens up a direct path from full images to the core of the tracker. While the results are still sub-par, we believe that this new, tight integration opens many interesting research opportunities and leads the way towards full end-to-end tracking from raw pixels.Comment: First two authors have equal contribution. This is initial work into a new direction, not a benchmark-beating method. v2 only adds acknowledgements and fixes a typo in e-mai

A modular DNA signal translator for the controlled release of a protein by an aptamer

Owing to the intimate linkage of sequence and structure in nucleic acids, DNA is an extremely attractive molecule for the development of molecular devices, in particular when a combination of information processing and chemomechanical tasks is desired. Many of the previously demonstrated devices are driven by hybridization between DNA ‘effector’ strands and specific recognition sequences on the device. For applications it is of great interest to link several of such molecular devices together within artificial reaction cascades. Often it will not be possible to choose DNA sequences freely, e.g. when functional nucleic acids such as aptamers are used. In such cases translation of an arbitrary ‘input’ sequence into a desired effector sequence may be required. Here we demonstrate a molecular ‘translator’ for information encoded in DNA and show how it can be used to control the release of a protein by an aptamer using an arbitrarily chosen DNA input strand. The function of the translator is based on branch migration and the action of the endonuclease FokI. The modular design of the translator facilitates the adaptation of the device to various input or output sequences