瑞士的桥梁荷载试验

本文对瑞士的桥梁荷载试验进行了介绍并对试验目的、试验方法及试验结果的分析等进行了讨论,最后给出了一座吊索桥的试验实例。     

Robust safety of timed automata

Timed automata are governed by an idealized semantics that assumes a perfectly precise behavior of the clocks. The traditional semantics is not robust because the slightest perturbation in the timing of actions may lead to completely different behaviors of the automaton. Following several recent works, we consider a relaxation of this semantics, in which guards on transitions are widened by Δ>0 and clocks can drift by ε>0. The relaxed semantics encompasses the imprecisions that are inevitably present in an implementation of a timed automaton, due to the finite precision of digital clocks. We solve the safety verification problem for this robust semantics: given a timed automaton and a set of bad states, our algorithm decides if there exist positive values for the parameters Δ and ε such that the timed automaton never enters the bad states under the relaxed semantics.     

On the expressiveness of TPTL and MTL

TPTL and MTL are two classical timed extensions of LTL. In this paper, we prove the 20-year-old conjecture that TPTL is strictly more expressive than MTL. But we show that, surprisingly, the TPTL formula proposed by Alur and Henzinger for witnessing this conjecture it can be expressed in MTL. More generally, we show that TPTL formulae using only modality F can be translated into MTL.     

Anthropometric 3D Face Recognition

We present a novel anthropometric three dimensional (Anthroface 3D) face recognition algorithm, which is based on a systematically selected set of discriminatory structural characteristics of the human face derived from the existing scientific literature on facial anthropometry. We propose a novel technique for automatically detecting 10 anthropometric facial fiducial points that are associated with these discriminatory anthropometric features. We isolate and employ unique textural and/or structural characteristics of these fiducial points, along with the established anthropometric facial proportions of the human face for detecting them. Lastly, we develop a completely automatic face recognition algorithm that employs facial 3D Euclidean and geodesic distances between these 10 automatically located anthropometric facial fiducial points and a linear discriminant classifier. On a database of 1149 facial images of 118 subjects, we show that the standard deviation of the Euclidean distance of each automatically detected fiducial point from its manually identified position is less than 2.54 mm. We further show that the proposed Anthroface 3D recognition algorithm performs well (equal error rate of 1.98% and a rank 1 recognition rate of 96.8%), out performs three of the existing benchmark 3D face recognition algorithms, and is robust to the observed fiducial point localization errors.     

Improved undecidability results on weighted timed automata

In this paper, we strengthen two recent undecidability results about weighted timed automata, an extension of timed automata with cost variables. More precisely, we propose new encodings of a Minsky machine that only require three clocks and one stopwatch cost, while previous reductions required five clocks and one stopwatch cost.     

Submicrometer in-plane integrated surface plasmon cavities

The optical properties of in-plane integrated surface plasmon polariton (SPP) cavities comprised of a thin film area sandwiched between two one-dimensional Bragg SPP mirrors are investigated numerically and experimentally. We discuss the resonance condition of these cavities, and we analyze in details the physical origin of the dispersion of this resonance. On the basis of numerical results, we show that in-plane SPP cavities can be used to achieve local SPP field enhancement and antireflecting SPP layers. The numerical results are compared to near-field optical images recorded by operating a photon scanning tunneling microscope. From the near-field images recorded over cavities with different sizes at different frequencies, we verify the resonance condition obtained numerically and we measure the quality factor of a submicrometer in-plane integrated SPP cavity.