Heuristics and Lower Bounds for the Simple Assembly Line Balancing Problem Type 1: Overview, Computational Tests and Improvements

Assigning tasks to work stations is an essential problem which needs to be addressed in an assembly line design. The most basic model is called simple assembly line balancing problem type 1 (SALBP-1). We provide a survey on 12 heuristics and 9 lower bounds for this model and test them on a traditional and a lately-published benchmark dataset. The present paper focuses on algorithms published before 2011. We improve an already existing dynamic programming and a tabu search approach significantly. These two are also identified as the most effective heuristics; each with advantages for certain problem characteristics. Additionally we show that lower bounds for SALBP-1 can be distinctly sharpened when merging them and applying problem reduction techniques

Testing Invisible Momentum Ansatze in Missing Energy Events at the LHC

We consider SUSY-like events with two decay chains, each terminating in an invisible particle, whose true energy and momentum are not measured in the detector. Nevertheless, a useful educated guess about the invisible momenta can still be obtained by optimizing a suitable invariant mass function. We review and contrast several proposals in the literature for such ansatze: four versions of the M_T2-assisted on-shell reconstruction (MAOS), as well as several variants of the on-shell constrained M_2 variables. We compare the performance of these methods with regards to the mass determination of a new particle resonance along the decay chain from the peak of the reconstructed invariant mass distribution. For concreteness, we consider the event topology of dilepton ttbar events and study each of the three possible subsystems, in both a ttbar and a SUSY example. We find that the M_2 variables generally provide sharper peaks and therefore better ansatze for the invisible momenta. We show that the performance can be further improved by preselecting events near the kinematic endpoint of the corresponding variable from which the momentum ansatz originates.Comment: 38 pages, 15 figure

The Atmospheric Knowing of Play: An Extraction Barometer?

he idea for the second contribution emerged upon reading the essay, Introduction: For an Ethology of Exhaustion by Christoph Brunner, Halbe, Hessel Kuipers and Toni Pape. Initially, it was this paper that was going to be explored within this zine. After preliminary conversations, it became clear that while the paper would serve as one axis to discuss the kind of loss one experiences in the process of new ways of knowing, Toni’s experience with the guitar as an ‘amateur’ player would would be what the zine to explores. Two kinds of loss were unpacked in different ways. On the topic of loss and pleasure of new ways of knowing experienced through exhaustion, Toni had an exchange with dramaturge Nienke Scholts on 15th March 2022. The written piece written by Toni on the kind of loss experienced as an amateur musician, is what follows

The application of circular polarized light in soil micromorphology.

[120.031]Most polarization microscopes can be adapted to circular polarization without the need for expensive accessories. In soil micromorphological studies it eliminates the extinction phenomena caused by anusotropic compounds in thin sections, which is advantageous for direct observations, quantitative analyses and for microphotographical purposes. The method is especially valuable when a large microscope stage is used, which prevents turning of the table or the crossed polarizers. (Abstract retrieved from CAB Abstracts by CABI’s permission