Compositional nonblocking verificationusing generalised nonblocking abstractions

This paper proposes a method for compositional verification of the standard and generalized nonblocking properties of large discrete event systems. The method is efficient as it avoids the explicit construction of the complete state space by considering and simplifying individual subsystems before they are composed further. Simplification is done using a set of abstraction rules preserving generalized nonblocking equivalence, which are shown to be correct and computationally feasible. Experimental results demonstrate the suitability of the method to verify several large-scale discrete event systems models both for standard and generalized nonblocking

NILS: a Neutrality-based Iterated Local Search and its application to Flowshop Scheduling

This paper presents a new methodology that exploits specific characteristics from the fitness landscape. In particular, we are interested in the property of neutrality, that deals with the fact that the same fitness value is assigned to numerous solutions from the search space. Many combinatorial optimization problems share this property, that is generally very inhibiting for local search algorithms. A neutrality-based iterated local search, that allows neutral walks to move on the plateaus, is proposed and experimented on a permutation flowshop scheduling problem with the aim of minimizing the makespan. Our experiments show that the proposed approach is able to find improving solutions compared with a classical iterated local search. Moreover, the tradeoff between the exploitation of neutrality and the exploration of new parts of the search space is deeply analyzed

Viking Force: Canada’s Unknown Commandos

Most people interested in Canadian military history know about hte elite first Special Battalion, formed in July 1942 as the Canadian element of the largely American First Sepcial Service Force.1 Few, however, have ever heard of Viking Force, Canada’s first attempt at creating an elite Commando unit in the Second World War. Viking Force does not appear in any Canadian Army Order of Battle, and did not even last long enough for its members to put on the unit’s horned-helmet shoulder patch, yet it played an important role in the sad story of the Dieppe fiasco. Acknowledgment of that role is long overdue

Analysis of a new tool for electrode positioning on the scalp according to the international 10/20 system

The emergence of non-invasive electromagnetic brain stimulation techniques, together with the improvement of electrophysiological recordings, has led to the need to increase the precision of the localization of cranial points close to their cortical target. In the clinical practice, the most common technique for locating there points on the scalp is the International 10/20 system and tape measure and a marker pen are used to carry out the marking process, before the placement of the electrodes. In this study, we have compared the marking for different electrophysiological tests between the conventional method and a new method based on the EPlacement device. The comparison was made taking into account the time spent on each test, the mean distance error per electrode, the direction of the error using the coordinate sign and, finally, a survey of healthcare staff to get their opinions on the 1S-EP and 2S-EP variants of EPlacement. The study involved 10 healthcare workers, 5 of whom had experience in conventional marking and 5 had experience in using the EPlacement device. 90 markings on dummies and 10 markings on volunteers were performed. Once each marking was completed on the dummies, the distances between the experimental points (marked with the EPlacement and tap measure) and the reference positions from 10/20 system determined by a 3D printed template were measured. The results show that with EPlacement, marking accuracy is increased, marking time is reduced, and healthcare personnel is receptive to adopting this technology.We would like to thank the collaborating healthcare staff of the Clinical Neurophysiology Service of the Hospital Universitari Sant Joan de Reus and Ismael Ávila for their support in the clinical research plan. This project has obtained funding from the Research to Business call (R2B2021-02), co-funded by the URV and the European Regional Development Fund (ERDF).Postprint (published version

Bose-Einstein condensation of indirect excitons in coupled quantum wells

We study the ground-state properties of a quasi-two-dimensional Bose-Einstein condensate of indirect excitons, which are confined in an anisotropic harmonic potential. Incorporating the interactions, we calculate the order parameter variationally. The difficulties in the detection of a Bose-Einstein condensate are also discussed, along with possible ways which would overcome them.Comment: 13 pages, RevTex, to appear in the Journal of Low Temp. Physic

Long-run effects of public sector sponsored training in West Germany

"Between 1991 and 1997 West Germany spent on average about 3.6 bn Euro per year on public sector sponsored training programmes for the unemployed. We base our empirical analysis on a new administrative data base that plausibly allows for selectivity correction by microeconometric matching methods. We identify the effects of different types of training programmes over a horizon of more than seven years. Using bias corrected weighted multiple neighbours matching we find that all programmes have negative effects in the short run and positive effects over a horizon of about four years. However, for substantive training programmes with duration of about two years gains in employment probabilities of more than 10% points appear to be sustainable, but come at the price of large negative lock-in effects." (Author's abstract, IAB-Doku) ((en))Arbeitsförderung, Kurzarbeit, Arbeitsbeschaffung, Vorruhestand, Weiterbildung, Umschulung, Rehabilitationsmaßnahme, arbeitsmarktpolitische Maßnahme - Erfolgskontrolle, IAB-Beschäftigtenstichprobe, prozessproduzierte Daten, Teilnehmerauswahl, Teilnehmerstruktur, Teilnehmer, Beschäftigungseffekte, Lock-in-Effekte, Westdeutschland, Bundesrepublik Deutschland

Non-LTE aluminium abundances in late-type stars

Aluminium plays a key role in studies of the chemical enrichment of the Galaxy and of globular clusters. However, strong deviations from LTE (non-LTE) are known to significantly affect the inferred abundances in giant and metal-poor stars. We present NLTE modeling of aluminium using recent and accurate atomic data, in particular utilizing new transition rates for collisions with hydrogen atoms, without the need for any astrophysically calibrated parameters. For the first time, we perform 3D NLTE modeling of aluminium lines in the solar spectrum. We also compute and make available extensive grids of abundance corrections for lines in the optical and near-infrared using one-dimensional model atmospheres, and apply grids of precomputed departure coefficients to direct line synthesis for a set of benchmark stars with accurately known stellar parameters. Our 3D NLTE modeling of the solar spectrum reproduces observed center-to-limb variations in the solar spectrum of the 7835 {\AA} line as well as the mid-infrared photospheric emission line at 12.33 micron. We infer a 3D NLTE solar photospheric abundance of A(Al) = 6.43+-0.03, in exact agreement with the meteoritic abundance. We find that abundance corrections vary rapidly with stellar parameters; for the 3961 {\AA} resonance line, corrections are positive and may be as large as +1 dex, while corrections for subordinate lines generally have positive sign for warm stars but negative for cool stars. Our modeling reproduces the observed line profiles of benchmark K-giants, and we find abundance corrections as large as -0.3 dex for Arcturus. Our analyses of four metal-poor benchmark stars yield consistent abundances between the 3961 {\AA} resonance line and lines in the UV, optical and near-infrared regions. Finally, we discuss implications for the galactic chemical evolution of aluminium.Comment: 20 pages, 15 figures. Accepted for publication in A&