A Hybrid Global Minimization Scheme for Accurate Source Localization in Sensor Networks

We consider the localization problem of multiple wideband sources in a multi-path environment by coherently taking into account the attenuation characteristics and the time delays in the reception of the signal. Our proposed method leaves the space for unavailability of an accurate signal attenuation model in the environment by considering the model as an unknown function with reasonable prior assumptions about its functional space. Such approach is capable of enhancing the localization performance compared to only utilizing the signal attenuation information or the time delays. In this paper, the localization problem is modeled as a cost function in terms of the source locations, attenuation model parameters and the multi-path parameters. To globally perform the minimization, we propose a hybrid algorithm combining the differential evolution algorithm with the Levenberg-Marquardt algorithm. Besides the proposed combination of optimization schemes, supporting the technical details such as closed forms of cost function sensitivity matrices are provided. Finally, the validity of the proposed method is examined in several localization scenarios, taking into account the noise in the environment, the multi-path phenomenon and considering the sensors not being synchronized

Atomic Parity Violation : Principles, Recent Results, Present Motivations

We review the progress made in the determination of the weak charge, Q\_w, of the cesium nucleus which raises the status of Atomic Parity Violation measurements to that of a precision electroweak test. Not only is it necessary to have a precision measurement of the electroweak asymmetry in the highly forbidden 6S-7S transition, but one also needs a precise calibration procedure. The 1999 precision measurement by the Boulder group implied a 2.5 sigma deviation of Q\_w from the theoretical prediction. This triggered many particle physicist suggestions as well as examination by atomic theoretical physicists of several sources of corrections. After about three years the disagreement was removed without appealing to "New Physics". Concurrently, an original experimental approach was developed in our group for more than a decade. It is based on detection by stimulated emission with amplification of the left- right asymmetry. We present our decisive, recent progress together with our latest results. We emphasize the important impact for electroweak theory, of future measurements in cesium possibly pushed to the 0.1% level. Other possible approaches are currently explored in several atoms

Long life hydraulic brake system. Final technical report.

National Highway Traffic Safety Administration, Washington, D.C.Mode of access: Internet.Author corporate affiliation: Science Applications, Inc., Los Angeles, Calif.Report covers the period Oct 1977-March 1979. Released October 1979. Contract amount - $172,376Subject code: DECSubject code: DOBCSubject code: NCYSubject code: NHLSubject code: NKJCSubject code: NOB*DOSubject code: RCGE*DOSubject code: WWCSubject code: YC

Long life hydraulic brake system. Summary report. Final report.

National Highway Traffic Safety Administration, Washington, D.C.Mode of access: Internet.Author corporate affiliation: Science Applications, Inc., Los Angeles, Calif.Report covers the period Oct 1977-March 1979. Released Oct 1979. Contract amount - $172,376Subject code: DECSubject code: DOBCSubject code: NCYSubject code: NHLSubject code: NKJCSubject code: NOB*DOSubject code: RCGE*DOSubject code: WWCSubject code: YC