Digital Simulation Algorithms Using Parallel Processing

Algorithms are presented which reduce the computation time per integration step compared to the more common methods. This is accomplished by using only algorithms which permit the simultaneous calculation of x and f(x) where x = f(x). These results are important not only in the field of digital simulation, but also in realizing dynamic controllers/estimators digitally, e.g., realizing a nonlinear observer.     

Epitaxial lateral overgrowth of InP by liquid-phase epitaxy on InP (0 0 1), (1 1 1)A,B and (1 1 0) surfaces

The epitaxial lateral overgrowth (ELO) was performed on {0 0 1}, {1 1 1}A,B and {1 1 0} oriented InP by liquid-phase epitaxy at constant growth temperature (450–650°C). According to the observations of cross-sectional shape, the orientation dependence of the vertical growth rate was determined to be {1 1 0}>{1 1 1}A,B>{1 0 0} under the present experimental conditions. The etch pit density in the ELO layer was lower than on openings. In PL mapping observations, PL properties were improved on the ELO layer.     

Adaptive equalization algorithms for optimization of a generalized mean square cost

Algorithms described in the literature for adaptation of equalizers usually consider minimization of a mean square cost. The mean square cost considered is usually comprised of two components; one component is the mean square error which arises because of inexact equilization of the channel response to the desired response. The other component can be identified as the mean square value of the noise at the output of the equalizer which is generated by channel noise.The paper describes algorithms which enable the two components to be independently weighted and the weighted mean square error minimized by the adaptive algorithms.Motivation for considering the independent weight is discussed in relation to the use of a compromised Viterbi algorithm receiver for the recovery of digital data transmitted over a noisy dispersive channel. However, other applications also exist.     

Perception of contradictory speech by normal and disturbed children at various age levels.

Recordings were made of female teachers reciting congruent and contradictory messages. In the congruent condition, the verbal and tonal elements of the communication were consistent. In the contradictory condition, the tone of voice was incongruent with the words spoken. All the congruent and contradictory vocal expressions were arranged in random order on a single tape and played to "normal" and "disturbed" boys of different ages (Grades 2, 4, and 6). Significant effects were found for type of speech and age: Ss reacted more negatively to contradictory than to congruent speech, and younger Ss responded more negatively to contradiction than did older ones. The disturbed Ss reacted significantly more negatively than normal Ss to contradictory messages. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use-definition chains with applications

Methods of compile-time program analysis for automatic code optimization usually include control flow analysis, in which possible execution flow paths are modeled, and data flow analysis, in which data relatiohsips are modeled. One representation of data relations in a program, via use-definition chains, is examined in the light of a particular example problem—the global elimination of “useless” computation. Two elimination algorithms which use differently organized use-definition chains are presented and compared for space complexity on two pathologically different families of flow graphs. Algorithms to compute chains of both varieties are also developed.     

Synthesis of alternating polyamideurethans by reacting diisocyanates with N,N′-di-(6-hydroxy-caproyl)alkylenediamines and N-hydroxy-alkyl-6-hydroxycaproamide

Polyamideurethans of structures I and II were prepared by reacting N,N′-di-(6-hydroxycaproyl)alkylenediamines and N-hydroxyalkyl-6-hydroxycaproamide with hexa-methylene diisocyanate and 4,4′-diphenylmethane diisocyanate: where R₁ is either a dimethylene or hexamethylene radical, and R₂ is a hexamethylene or 4,4′-diphenylmethane radical. Polymers I and II were of a high degree of polymerization and crystallinity, had high enough melting points for practical use, and gave colorless tough films both by dry and melt castings. The polymers from hexamethylene diisocyanate were much more crystalline and thermally more stable above the melting points than those from 4,4′-diphenylmethane diisocyanate. Polymerization conditions and characteristic properties of the resulting polymers were studied.