Available proper motion measurements of Milky Way (MW) satellite galaxies are used to calculate their orbital poles and projected uncertainties. These are compared to a set of recent cold dark-matter (CDM) simulations, tailored specifically to solve the MW satellite problem. We show that the CDM satellite orbital poles are fully consistent with being drawn from a random distribution, while the ...

Interest in evaluating conceptual modelling techniques has recently experienced a revival, in part due to widespread adoption of the Unified Modelling Language (UML). In addition, the use of ontology as a framework for evaluating conceptual modelling techniques has gained acceptance. In this paper, we consider implications of applying one aspect of the ontology of Mario Bunge to conceptual mode...

Space systems engineering demand coordinated expertise from different disciplines. Furthermore, satellite systems are growing even more complex making conceptual design a key driver for cost and deadline. When poorly performed, various problems may arise. One solution is to underpin this project phase with a collaborative systems engineering environment and by adoption of a model-driven enginee...

in this paper satellite wave propagation at ku and ka band is considered. the design and simulation of a typical satellite beacon receiver at ka band is designed and simulated for the future works. also rain attenuation prediction at ku band using satellite signal beacon measurement and simulations for iran telecommunication research center (itrc) are presented. the measurement setup consists o...