The Structure of the Set of Equilibria for Two Person Multicriteria Games

In this paper the structure of the set of equilibria for two person multicriteria games is analysed. It turns out that the classical result for the set of equilibria for bimatrix games, that it is a finite union of polytopes, is only valid for multicriteria games if one of the players only has two pure strategies. A full polyhedral description of these polytopes can be derived when the player with an arbitrary number of pure strategies has one criterion.game theory;equilibrium theory

Multilevel MDA-Lite Paris Traceroute

Since its introduction in 2006-2007, Paris Traceroute and its Multipath Detection Algorithm (MDA) have been used to conduct well over a billion IP level multipath route traces from platforms such as M-Lab. Unfortunately, the MDA requires a large number of packets in order to trace an entire topology of load balanced paths between a source and a destination, which makes it undesirable for platforms that otherwise deploy Paris Traceroute, such as RIPE Atlas. In this paper we present a major update to the Paris Traceroute tool. Our contributions are: (1) MDA-Lite, an alternative to the MDA that significantly cuts overhead while maintaining a low failure probability; (2) Fakeroute, a simulator that enables validation of a multipath route tracing tool's adherence to its claimed failure probability bounds; (3) multilevel multipath route tracing, with, for the first time, a Traceroute tool that provides a router-level view of multipath routes; and (4) surveys at both the IP and router levels of multipath routing in the Internet, showing, among other things, that load balancing topologies have increased in size well beyond what has been previously reported as recently as 2016. The data and the software underlying these results are publicly available.Comment: Preprint. To appear in Proc. ACM Internet Measurement Conference 201

Environment of compact extragalactic radio sources

We have studied the interrelation of young AGN with their hosts. The objects of study are the young and powerful GPS and CSS radio sources. Due to their small size, GPS and CSS sources are excellent probes of this relation. Furhthermore, their young age allows us to compare them to the larger, old radio sources and establish a time-line evolution of this relation. Combining imaging and spectroscopy at UV, optical and radio wavelengths we find evidence of strong interaction between the host and the radio source. The presence and expansion of the radio source clearly affects the properties and evolution of the host. Furthermore, the radio source and host significantly affect each other's evolution. We describe our results and how these interactions take place.Comment: 6 pages. To appear in "Highlights of Spanisg astrophysics IV. Proceedings of the VII scientific meeting of the Spanish Astronomical Society". Editors: F. Figueras, J.M. Girart, M.Hernanz, C. Jordi. Springe

Health monitoring of federated future internet experimentation facilities

The federation of Future Internet testbeds as envisaged by the Fed4FIRE project is a complex undertaking. It combines a large number of existing, independent testbeds in a single federation, and presents them to the experimenter as if it were a single infrastructure. Operating and using such an infrastructure requires a profound knowledge of the status of the health of the underlying independent systems. Inspired by network monitoring techniques used to operate the Internet today, this paper considers how a centralized health monitoring system can be set up in a federated environment of Future Internet Experimentation Facilities. We show why it is a vital tool for experimenters and First Level Support in the federation, which health monitoring information must be captured, and how this information can be displayed most appropriately

Twenty Years of Timing SS433

We present observations of the optical ``moving lines'' in spectra of the Galactic relativistic jet source SS433 spread over a twenty year baseline from 1979 to 1999. The red/blue-shifts of the lines reveal the apparent precession of the jet axis in SS433, and we present a new determination of the precession parameters based on these data. We investigate the amplitude and nature of time- and phase-dependent deviations from the kinematic model for the jet precession, including an upper limit on any precessional period derivative of $\dot P < 5 \times 10^{-5}$. We also dicuss the implications of these results for the origins of the relativistic jets in SS433.Comment: 21 pages, including 9 figures. To appear in the Astrophysical Journa

A Multi-Epoch VLBI Survey of the Kinematics of CJF Sources; Part I: Model-Fit Parameters and Maps

Context: This is the first of a series of papers presenting VLBI observations of the 293 Caltech-Jodrell Bank Flat-Spectrum (hereafter CJF) sources and their analysis. Aims: One of the major goals of the CJF is to make a statistical study of the apparent velocities of the sources. Methods: We have conducted global VLBI and VLBA observations at 5 GHz since 1990, accumulating thirteen separate observing campaigns. Results: We present here an overview of the observations, give details of the data reduction and present the source parameters resulting from a model-fitting procedure. For every source at every observing epoch, an image is shown, built up by restoring the model-fitted components, convolved with the clean beam, into the residual image, which was made by Fourier transforming the visibility data after first subtracting the model-fitted components in the uv-plane. Overplotted we show symbols to represent the model components. Conclusions: We have produced VLBI images of all but 5 of the 293 sources in the complete CJF sample at several epochs and investigated the kinematics of 266 AGN.Comment: Figure 1 and Table 2 are only available in electronic form at the CDS and soon at http://www.mpifr-bonn.mpg.de/staff/sbritzen/cjf.htm

Variability and Velocity of Superluminal Sources

We investigate the relation between the Doppler factor determined from variations in total flux at 22 and 37 GHz, and the apparent transverse velocity determined from VLBA observations at 2 cm. The data are consistent with the relativistic beaming theory for compact radio sources, in that the distribution of beta_{app}/delta_{var}, for 30 quasars, is roughly consistent with a Monte Carlo simulation. The intrinsic temperature appears to be ~2x10^{10} K, close to the "equipartition value" calculated by Readhead (1994). We deduce the distribution of Lorentz factors for a group of 48 sources; the values range up to about gamma=40.Comment: To be published in "Radio Astronomy at the Fringe", ASP Conf. Ser. Vol. 300, J. A. Zensus, M. H. Cohen, & E. Ros (eds.), 8 pages, 3 figures, needs rafringe.st