O projektiranju, mjerenjima i robusnoj regulaciji u bežičnim telekomunikacijskim mrežama

Over the years a lot of rigorous mathematical analysis has been done by systems and controls community for the optimization of multivariable systems with a mathematically rigorous systems theoretic approach. In parallel, wireless telecommunication industry was working on performance measurement analysis tools achieving demonstrable optimization. This paper will elaborate on the need for finding common grounds these two approaches. Some existing measurement tools are also presented. Decision on measurement tools in design of telecommunications networks implies tradeoffs between reliability, capacity, and the economics in meeting customer demands. The paper first identifies the parameters which can and should be measured to facilitate the optimization for performance of telecommunication networks. Secondly, there are given available resources on measurements tools for these parameters together with a comparative analysis. Thirdly, the hardware setup for some of these measurements will be explained. Finally, a method to find the robust controller for wireless network is introduced.Kroz godine je mnogo postignuto u optimizaciji multivarijabilnih sustava kroz rigorozan matematički teoretski pristup. U isto vijeme, u bežičnoj telekomunikacijskoj industriji radilo se na metodama za mjerenje i analizu kako se moglo optimirati rad telekomunikacijske mreže. Glavna tema ovog rada je uvod u analizu koja povezuje teoriju regulacijskih sustava i optimiranje rada bežičnih telekomunikacijskih mreža. Neke postojeće mjerne metode su također objašnjene. Izbor mjernih metoda i mjerenja potrebnih za uspostavljanje optimalne i pouzdane bežične telekomunikacijske mreže uključuje uspostavljanje ravnoteže između pouzdanosti, kapaciteta i cijene u zadovoljavanju trenutnih i budućih potreba korisnika. Uspostavljanje i održavanje efikasne bežične telekomunikacijske mreže jesvakodnevni izazov. Ovaj rad prvo identificira parametre koji mogu i trebaju biti mjereni kako bi se omogućilo optimiranje rada mreže. Zatim je data kratka analiza opreme za mjerenje uz objašnjenje hardwera za takva mjerenja. Na kraju je dana struktura robusnog regulatora za bežične telekomunikacijske mreže

A Molecular Einstein Ring at z=4.12: Imaging the Dynamics of a Quasar Host Galaxy Through a Cosmic Lens

We present high-resolution (0.3") Very Large Array (VLA) imaging of the molecular gas in the host galaxy of the high redshift quasar PSS J2322+1944 (z=4.12). These observations confirm that the molecular gas (CO) in the host galaxy of this quasar is lensed into a full Einstein ring, and reveal the internal dynamics of the molecular gas in this system. The ring has a diameter of ~1.5", and thus is sampled over ~20 resolution elements by our observations. Through a model-based lens inversion, we recover the velocity gradient of the molecular reservoir in the quasar host galaxy of PSS J2322+1944. The Einstein ring lens configuration enables us to zoom in on the emission and to resolve scales down to ~1 kpc. From the model-reconstructed source, we find that the molecular gas is distributed on a scale of 5 kpc, and has a total mass of M(H2)=1.7 x 10^10 M_sun. A basic estimate of the dynamical mass gives M_dyn = 4.4 x 10^10 (sin i)^-2 M_sun, that is, only ~2.5 times the molecular gas mass, and ~30 times the black hole mass (assuming that the dynamical structure is highly inclined). The lens configuration also allows us to tie the optical emission to the molecular gas emission, which suggests that the active galactic nucleus (AGN) does reside within, but not close to the center of the molecular reservoir. Together with the (at least partially) disturbed structure of the CO, this suggests that the system is interacting. Such an interaction, possibly caused by a major `wet' merger, may be responsible for both feeding the quasar and fueling the massive starburst of 680 M_sun/yr in this system, in agreement with recently suggested scenarios of quasar activity and galaxy assembly in the early universe.Comment: 9 pages, 7 figures, to appear in ApJ (accepted June 27, 2008