NASTRAN multipartitioning and one-shot substructuring

For intermediate size problems where all the data is accessible, the present method of substructuring in three separate phases (for static analysis) is unneccessarily cumbersome. The versatility of NASTRAN's DMAP and internal logic lends itself to finding a practical alternative to these procedures whereby self-contained special-purpose ALTER packages can be written to be run in one pass. Two examples are presented here under the titles of multipartitioning and one-shot substructuring. The flow of multipartitioning resembles that of the present three-phase substructuring. The basic effect is to partition the structure into substructures and operate on each substructure separately. This can be used to reduce the bandwidth of a given problem as well as to store information which will allow a change to be made in one of the substructures in a later run. This latter procedure is carried out in a second program titled one-shot substructuring

Optimization of 2D CT Data Sets for Three-Dimensional

Computer-generated anatomic modeling using radiologic data is a well-known entity. Currently, state of the art 3D modeling systems lack the variable thresholding, user interactive, capabilities of 3D imaging software.1 We investigated clinical parameters - cr scan plane, 2D filter algorithm, surrounding medium - and tested a simple mathematical thresholding algorithm based upon experimentation with a cr phantom, to evaluate a semiautomated approach to 3D craniofacial imaging and model generation. (Figure 1)Mechanical Engineerin

A Note on Income Inequality and Macro-economic Volatility

Income inequality may influence macro-economic variables by affecting the money multiplier and the trade-off between inflation and output. In an AD-AS model with imperfect foresight income inequality intensifies the volatility of output and inflation rate by increasing the likelihood of oscillations as well as their magnitude. Volatility is, however, moderated when income inequality prolongs the business cycles.Rational eating, cycles

Profit and Non-Profit Maximising Network Density, Membership Fees and Service in Monopolistic and Duopolistic Framework.

Network density, membership fees and service are analytically related to factors such as the size of the target population, the distribution of ability to enjoy the networl's service within target population, the tax-regbate on membership payment, the service production costs, which are increased by congestion or reduced by agglomeration, and the network organisational costs. The analysis is conducted for the case of budget-balancing and density-targeting networks.ENTERPRISES ; INDUSTRY ; MEMBERSHIP

From Hotelling to Backstop Technology.

Hotelling's conceptual framework is expanded to incorporate the effects of a backstop technology on the planning horizon of the suppliers of an exhaustible resource and its price and quantity trajectories. It is shown that in the non-trivial case, the presence of a backstop technology shortens the planning horizon of the suppliers of the exhaustible resource in accordance with the resource suppliers' rate of time preference, backstop technology's rate of irnprovement and ratio of the initial resource spot price to the initial average production cost of the backstop substitute. As expected the presence of a backstop technology also lowers the spot prices of the exhaustible resource and accelerates its extraction and depletion. However, a decline of the initial average cost of producing the backstop substitute by a dollar leads to a decline of the exhaustible resource's initial spot price by less than a dollar.TECHNOLOGY ; PRICING ; ECONOMIC MODELS

Rational Non-addictive Eating: Cycles, Overweightness, and Underweightness

Although a deviation from the physiologically optimal weight increases the probability of dying, the steady state for a lifetime expected-utility maximiser is a state of overweightness. However, even a small initial deviation from this rationally stationary weight is followed by explosive oscillations. These oscillations might lead to severe and chronic underweightness in a late stage of life. In the presence of socio-cultural norms of appearance, the rationally stationary weight of fat people is lower than otherwise and the rationally stationary weight of lean people is greater than otherwise.Rational eating, cycles

The Andreev states of a superconducting quantum dot: mean field vs exact numerical results

We analyze the spectral density of a single level quantum dot coupled to superconducting leads focusing on the Andreev states appearing within the superconducting gap. We use two complementary approaches: the numerical renormalization group and the Hartree-Fock approximation. Our results show the existence of up to four bound states within the gap when the ground state is a spin doublet (\pi\ phase). Furthermore the results demonstrate the reliability of the mean field description within this phase. This is understood from a complete correspondence that can be established between the exact and the mean field quasiparticle excitation spectrumComment: 6 pages, 5 figure

Life-Expectancy Augmented Rational Addition: A Note.

The Becker-Murphy equality between the addictive commodity's full price and marginal utility is modified by discounting the market price and marginal utility of the addictive commodity by the probability of living at least until the time under consideration. the rate of change of the shadow price of addiction is lower than that obtained with models ignoring the effectof addiction on the probability of dying.RATIONAL EXPECTATIONS