Signaling traffic volume generated by mobile and personalcommunications

The authors develop a framework for evaluating the signaling load in a wireless network. Using bounds and approximations, we find that the key parameter to estimate is the number of location updates between two calls. The results are dependent upon the choice of protocols, but are independent of the traffic parameters relating user calling behavior and mobility. We use the framework to draw general conclusions about signaling load, as well as to compare the signaling loads for the European and North American systems and demonstrate the impact of architectural tradeoffs. We also describe the message flows for the major contributors to the signaling load that are defined in the GSM system     

A continuum model of a solid with a free surface: I. Normal mode analysis of the model

A complete analysis is made of the normal modes of an isotropic continuum model of a solid which occupies the region (0, 0, 0) < (x, y, z) < (X, Y, Z), the limit (X, Y, Z) → (∞,∞,∞) being taken. The surface z = 0 is a free surface and that z = Z is fixed; cyclic boundary conditions are used in the x and y directions. The modal displacements (vectors), modal frequencies (as a function of the wave-vectors), and wave-vector-densities are obtained for all types of normal modes; the work is a modification and extension of that of earlier workers.     

Neural networks applied to traffic management in telephone networks

In this paper the application of neural networks to some of the network management tasks carried out in a regional Bell telephone company is described. Network managers monitor the telephone network for abnormal conditions and have the ability to place controls in the network to improve traffic flow. Conclusions are drawn regarding the utility and effectiveness of the neural networks in automating the network management tasks     

Low temperature raman evidence for two crystalline phases of methylcyclohexane

Comparison of the lattice mode region of the low-temperature Raman spectrum of MCH and MCH-d₁₄ under various cooling rates shows that there are two crystalline modifications. The molecular mode region frequencies however, remain invariant to cooling rate suggesting a single molecular conformation for both crystalline phases.     

Newton's method for constrained optimization

We derive a quadratically convergent algorithm for minimizing a nonlinear function subject to nonlinear equality constraints. We show, following Kaufman [4], how to compute efficiently the derivative of a basis of the subspace tangent to the feasible surface. The derivation minimizes the use of Lagrange multipliers, producing multiplier estimates as a by-product of other calculations. An extension of Kantorovich's theorem shows that the algorithm maintains quadratic convergence even if the basis of the tangent space changes abruptly from iteration to iteration. The algorithm and its quadratic convergence are known but the drivation is new, simple, and suggests several new modifications of the algorithm.     

Proof of Grünbaum's conjecture on the stretchability of certain arrangements of pseudolines

We prove Grünbaum's conjecture that every arrangement of eight pseudolines in the projective plane is stretchable, i.e., determines a cell complex isomorphic to one determined by an arrangement of lines. The proof uses our previous results on ordered duality in the projective plane and on periodic sequences of permutations of [1,n] associated to arrangements of n lines in the euclidean plane.     

Shortwave propagation prediction methodologies

The status of ionospheric-propagation prediction models is examined, with particular emphasis on the use of these models by the shortwave-broadcast community. Their stand-alone capability for forecasts is found to be limited by the use of monthly median, statistical averages of archived ionospheric data, as well as by the use of imprecise control parameter inputs, such as the sunspot number. A variety of developing technologies are discussed for improvement of prediction models. Improvement may result from observations of coronal holes and other relevant solar features for long-term and short-term ionospheric predictions. Also discussed are a variety of other ionospheric measurement schemes for short-term ionospheric predictions, such as the use of vertical-incidence, oblique-incidence, and backscatter sensing from space. The application of this class of measurements for adaptive HF broadcasting systems is discussed. Incorporation of ray-tracing into propagation calculations in the prediction model is also considered     

Interaction of H2 and CO with carbided and nitrided Ni(100)

A comparison is made of the chemisorption behavior of H₂ and CO over a carbided and nitrided Ni(100) surface. These results together with previous results for S and Cl support the argument that adatom electronegativity rather than radius is primarily responsible for modification of chemisorption behavior.     

Near field stress analysis of a spot weld between elastic plates

The mechanics of a circular, spot weld between two identical elastic plates is studied. A method of solution similar to that used by the authors in a paper concerned with the influence of an elastic layer on the tangential compliance of bodies in contact is used. In the present analysis the relation between tangential load and deflection is lost due to the nature of the problem; hence, physical quantities are determined in terms of the total tangential load applied in the weld region.