Dynamic Soil-Pile-Structure Interaction

The largest compressor train in North America was installed for a new ethylene production plant at the Nova Chemicals Facility located near Joffre, Alberta. To illustrate the effect of soil-pile-structure interaction, the dynamic behavior of the structure using flexible piled foundation is compared to the same structure fixed to a rigid base in this paper. Both field and laboratory tests were carried out to investigate the soil properties including down hole seismic tests to provide soil shear wave velocities at different depths. Different design options are considered and an optimum design selected to limit vibration and produce a safe, economic system. The method and procedure used in this study can be applied to the design of tall buildings, bridges and offshore platform with soil-pile-structure interaction under seismic, blast, sea wave and other dynamic loads

On the Asymptotics of Quantizers in Two Dimensions

AbstractWhen the mean square distortion measure is used, asymptotically optimal quantizers of uniform bivariate random vectors correspond to the centers of regular hexagons (Newman, 1982), and if the random vector is non-uniform, asymptotically optimal quantizers are the centers of piecewise regular hexagons where the sizes of the hexagons are determined by a properly chosen density function (Su and Cambanis, 1996). This paper considers bivariate random vectors with finiteγth (γ>0) moment. If theγth mean distortion measure is used, a complete characterization of the asymptotically optimal quantizers is given. Furthermore, it is shown that the procedure introduced by Su and Cambanis (1996) is also asymptotically optimal for everyγ>0. Examples with a normal distribution and a Pearson type VII distribution are considered

Acyclic 4-choosability of planar graphs without 4-cycles

summary:A proper vertex coloring of a graph $G$ is acyclic if there is no bicolored cycle in $G$. In other words, each cycle of $G$ must be colored with at least three colors. Given a list assignment $L=\{L(v)\colon v\in V\}$, if there exists an acyclic coloring $\pi$ of $G$ such that $\pi (v)\in L(v)$ for all $v\in V$, then we say that $G$ is acyclically $L$-colorable. If $G$ is acyclically $L$-colorable for any list assignment $L$ with $|L(v)|\ge k$ for all $v\in V$, then $G$ is acyclically $k$-choosable. In 2006, Montassier, Raspaud and Wang conjectured that every planar graph without 4-cycles is acyclically 4-choosable. However, this has been as yet verified only for some restricted classes of planar graphs. In this paper, we prove that every planar graph with neither 4-cycles nor intersecting $i$-cycles for each $i\in \{3,5\}$ is acyclically 4-choosable

Sampling designs for estimation of a random process

A random process X(t), t ∈ [0, 1], is sampled at a finite number of appropriately designed points. On the basis of these observations, we estimate the values of the process at the unsampled points and we measure the performance by an integrated mean square error. We consider the case where the process has a known, or partially or entirely unknown mean, i.e., when it can be modeled as X(t) = m(t)+ N(t), where m(t) is nonrandom and N(t) is random with zero mean and known covariance function. Specifically, we consider (1) the case where m(t) is known, (2) the semiparametric case where m(t) = β1f1(t)+ . + βqfq(t), the βi's are unknown coefficients and the fi's are known regression functions, and (3) the nonparametric case where m(t) is unknown. Here fi(t) and m(t) are of comparable smoothness with the purely random part N(t), and N(t) has no quadratic mean derivative