Non-uniformity in data extents is a general characteristic of spatial data. Indexing such non-uniform data using conventional spatial index structures such as R -trees is inefficient for two reasons: (1) The non-uniformity increases the likelihood of overlapping index entries, and, (2) clustering of non-uniform data is likely to index more dead space than clustering of uniform data. To reduce t...

Let X be a locally finite tree, and let G = Aut(X). Then G is a locally compact group. We show that if X has more than one end, and if G contains a discrete subgroup Γ such that the quotient graph of groups Γ\\X is infinite but has finite covolume, then G contains a non-uniform lattice, that is, a discrete subgroup Λ such that Λ\G is not compact, yet has a finite G-invariant measure. 0. Notatio...

introduction: non-uniformity test is essentially the only required daily qc procedure in nuclear medicine practice. noise creates statistical variation or random error in a flood image. non-uniformity on the other hand does not have statistical nature and may be regarded as systemic error. the present methods of non-uniformity calculation do not distinguish between these two types of error. the...

Displacement finite element models of various beam theories have been developed traditionally using conventional finite element basis functions (i.e., cubic Hermite, equi-spaced Lagrange interpolation functions, or spectral/hp Legendre functions). Various finite element models of beams differ from each other in the choice of the interpolation functions used for the transverse deflection w, tota...

The purpose of the present study is to investigate the boundary layer separation point in a magnetohydrodynamics diffuser. As an innovation, the Re value on the separation point is determined for the non-Newtonian fluid flow under the influence of the non-uniform magnetic field due to an electrical solenoid, in an empirical case. The governing equations include continuity and momentum are solve...

In the present study, the microstructural changes of a Nickel based superalloy Nimonic80A during a non-isothermal deformation were studied. Therefore, microstructure evolutionduring hot side pressing test was predicted with combined methods of finite element analysis andprocessing map of the material. The predicted results were validated through experimentalmicrostructural studies. The results ...

Given positive integers n, k, t, with 2 ≤ k ≤ n, and t < 2, let m(n, k, t) be the minimum size of a family F of (nonempty distinct) subsets of [n] such that every k-subset of [n] contains at least t members of F , and every (k − 1)-subset of [n] contains at most t− 1 members of F . For fixed k and t, we determine the order of magnitude of m(n, k, t). We also consider related Turán numbers T≥r(n...

De, Trevisan and Tulsiani [CRYPTO 2010] show that every distribution over n-bit strings which has constant statistical distance to uniform (e.g., the output of a pseudorandom generator mapping n− 1 to n bit strings), can be distinguished from the uniform distribution with advantage by a circuit of size O(2 2). We generalize this result, showing that a distribution which has less than k bits of ...

Concurrent objects may offer services non-uniformly, constraining the acceptance of messages on the states of objects. We advocate a looser view of communication errors. Safe programmes must guarantee that every message has a chance of being received if it requests a method that may become enabled at some point in the future. We formalise non-uniform concurrent objects in TyCO, a name-passing o...

Exact reconstruction of a band-limited signal from its non-uniform samples involves the use of Lagrange interpolation, which is impractical to implement as it is computationally difficult. This thesis develops approximate reconstruction methods based on time-warping to obtain reconstruction of band-limited signals from non-uniform samples. A review of non-uniform sampling theorems is presented ...