Validation of a fault-tolerant clock synchronization system

A validation method for the synchronization subsystem of a fault tolerant computer system is investigated. The method combines formal design verification with experimental testing. The design proof reduces the correctness of the clock synchronization system to the correctness of a set of axioms which are experimentally validated. Since the reliability requirements are often extreme, requiring the estimation of extremely large quantiles, an asymptotic approach to estimation in the tail of a distribution is employed

Investigation of potential of differential absorption Lidar techniques for remote sensing of atmospheric pollutants

The NASA multipurpose differential absorption lidar (DIAL) system uses two high conversion efficiency dye lasers which are optically pumped by two frequency-doubled Nd:YAG lasers mounted rigidly on a supporting structure that also contains the transmitter, receiver, and data system. The DIAL system hardware design and data acquisition system are described. Timing diagrams, logic diagrams, and schematics, and the theory of operation of the control electronics are presented. Success in obtaining remote measurements of ozone profiles with an airborne systems is reported and results are analyzed

An experimental/analytical program to assess the utility of lidar for pollution monitoring

The development and demonstration of lidar techniques for the remote measurement of atmospheric constituents and transport processes in the lower troposphere was carried out. Particular emphasis was given to techniques for monitoring SO2 and particulates, the principal pollutants in power plant and industrial plumes. Data from a plume dispersion study conducted in Maryland during September and October 1976 were reduced, and a data base was assembled which is available to the scientific community for plume model verification. A UV Differential Absorption Lidar (DIAL) was built, and preliminary testing was done

People like us: gentrification and the service class in Hackney in the 1980s

This is a study of service-class residents in Hackney, an inner London borough situated directly to the north of the City of London. The main focus of the study is on why these people chose to live in Hackney in the first place, why they have stayed and what influence living in Hackney has had on their social and political attitudes. Chapters two to four are concerned with debates about the structure and class formation of the service-class, whether it is one class or many, what (if any) are its political allegiances, and the relationship between the service-class and gentrification. Chapter five considers the changes which have taken place in London and Hackney over the last fifteen years. Chapter six introduces the empirical basis for this discussion: a survey of 245 largely service-class recent homebuyers in two areas of Hackney. Chapters seven to nine present these findings which show that the respondents are representative of a distinct, and elite, sub-group of the service class, in terms of their family background, their income and occupation and in their social and political attitudes. Whilst many respondents initially came to Hackney because of its cheap housing and central location, their reasons for staying have more to do with the cultural significance of living in inner London. This, in turn, has had important consequences for their social, cultural and political behaviour. The concluding chapter suggests that there are 'locality effects' observable in the behaviour and attitudes of service-class residents in Hackney which are reasons for living in inner London and consequences of living there. There are also significant differences between the two areas studied which may have implications for the internal formation of the service-class even within a spatially delimited area, such as inner London

Jahn-Teller effect versus Hund's rule coupling in C60N-

We propose variational states for the ground state and the low-energy collective rotator excitations in negatively charged C60N- ions (N=1...5). The approach includes the linear electron-phonon coupling and the Coulomb interaction on the same level. The electron-phonon coupling is treated within the effective mode approximation (EMA) which yields the linear t_{1u} x H_g Jahn-Teller problem whereas the Coulomb interaction gives rise to Hund's rule coupling for N=2,3,4. The Hamiltonian has accidental SO(3) symmetry which allows an elegant formulation in terms of angular momenta. Trial states are constructed from coherent states and using projection operators onto angular momentum subspaces which results in good variational states for the complete parameter range. The evaluation of the corresponding energies is to a large extent analytical. We use the approach for a detailed analysis of the competition between Jahn-Teller effect and Hund's rule coupling, which determines the spin state for N=2,3,4. We calculate the low-spin/high-spin gap for N=2,3,4 as a function of the Hund's rule coupling constant J. We find that the experimentally measured gaps suggest a coupling constant in the range J=60-80meV. Using a finite value for J, we recalculate the ground state energies of the C60N- ions and find that the Jahn-Teller energy gain is partly counterbalanced by the Hund's rule coupling. In particular, the ground state energies for N=2,3,4 are almost equal

Labeling Schemes for Bounded Degree Graphs

We investigate adjacency labeling schemes for graphs of bounded degree $\Delta = O(1)$. In particular, we present an optimal (up to an additive constant) $\log n + O(1)$ adjacency labeling scheme for bounded degree trees. The latter scheme is derived from a labeling scheme for bounded degree outerplanar graphs. Our results complement a similar bound recently obtained for bounded depth trees [Fraigniaud and Korman, SODA 10], and may provide new insights for closing the long standing gap for adjacency in trees [Alstrup and Rauhe, FOCS 02]. We also provide improved labeling schemes for bounded degree planar graphs. Finally, we use combinatorial number systems and present an improved adjacency labeling schemes for graphs of bounded degree $\Delta$ with $(e+1)\sqrt{n} < \Delta \leq n/5$

Chromospheric CaII Emission in Nearby F, G, K, and M stars

We present chromospheric CaII activity measurements, rotation periods and ages for ~1200 F-, G-, K-, and M- type main-sequence stars from ~18,000 archival spectra taken at Keck and Lick Observatories as a part of the California and Carnegie Planet Search Project. We have calibrated our chromospheric S values against the Mount Wilson chromospheric activity data. From these measurements we have calculated median activity levels and derived R'HK, stellar ages, and rotation periods for 1228 stars, ~1000 of which have no previously published S values. We also present precise time series of activity measurements for these stars.Comment: 62 pages, 7 figures, 1 table. Second (extremely long) table is available at http://astro.berkeley.edu/~jtwright/CaIIdata/tab1.tex Accepted by ApJ

A robot-based burr measurement system for the automotive industry

Burrs are often difficult to detect and measure because of their intrinsic variability in shape and dimension. No automotive standard had been established about their acceptable dimensions and measurement techniques for sheet steel products. For the automotive industry, even burrs of the size of 100 μm are perceived as damaging because of their dramatic impact upon panel corrosion resistance and assembly performance. It is critical to measure burrs during panel manufacture in order to control the process. The characterization of the typical burr produced has been carried out employing 3D measurements with a surface profilometer and a SEM. This analysis has shown a typical triangular burr shape and some characteristic dimensions. A contact method and two laser-triangulation systems have been developed. The instrument accuracy was analyzed, based upon a full factorial experimentation over a set of typical panels edges