203 research outputs found
Division of Labour and Social Coordination Modes : A simple simulation model
This paper presents a preliminary investigation of the relationship between the process of functional division of labour and the modes in which activities and plans are coordinated. We consider a very simple production process: a given heap of bank-notes has to be counted by a group of accountants. Because of limited individual capabilities and/or the possibilities of mistakes and external disturbances, the task has to be divided among several accountants and a hierarchical coordination problem arises. We can imagine several different ways of socially implementing coordination of devided tasks. 1) a central planner can compute the optimal architecture of the system; 2) a central planner can promote quantity adjustments by moving accountants from hierarchical levels where there exist idle resources to levels where resources are insufficient; 3) quasi-market mechanisms can use quantity or price signals for promoting decentralized adjustments. By means of a simple simulation model, based on Genetic Algorithms and Classifiers Systems, we can study the dynamic efficiency properties of each coordination mode and in particular their capability, speed and cost of adaptation to changing environmental situations (i.e. variations of the size of the task and/or variations of agents' capabilities). Such interesting issues as returns to scale, specialization and workers exploitation can be easily studied in the same model
Distances on Cosmological Scales with VLTI
We present here a new method using interferometric measurements of quasars,
that allows the determination of direct geometrical distances on cosmic scales.
Quasar Broad Emission Line Regions sizes provide a "meter rule" with which to
measure the metric of the Universe. This method is less dependent of model
assumptions, and even of variations in the fundamental constants (other than
c). We discuss the spectral and spatial requirements on the VLTI observations
needed to carry out these measurements.Comment: 6 pages, 2 postscript figures, to appear in the proceedings of the
JENAM 2002 Workshop WS-VLTI "The Very Large Telescope Interferometer:
Challenges for the Future", Editors: P.J.V. Garcia, A. Glindemann, Th.
Henning, F. Malbet, Ap&SS, Kluwer, in pres
KIC 8462852 - The Infrared Flux
We analyzed the warm Spitzer/IRAC data of KIC 8462852. We found no evidence
of infrared excess at 3.6 micron and a small excess of 0.43 +/- 0.18 mJy at 4.5
micron, below the 3 sigma threshold necessary to claim a detection. The lack of
strong infrared excess 2 years after the events responsible for the unusual
light curve observed by Kepler, further disfavors the scenarios involving a
catastrophic collision in a KIC 8462852 asteroid belt, a giant impact
disrupting a planet in the system or a population of a dust-enshrouded
planetesimals. The scenario invoking the fragmentation of a family of comets on
a highly elliptical orbit is instead consistent with the lack of strong
infrared excess found by our analysis.Comment: Published on The Astrophysical Journal Letter
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