Continuous phase quadrature phase shift keyed signaling techniquewith coding

A continuous phase quadrature phase shift keyed (CPQPSK) modulation technique is presented. This method utilizes a conventional QPSK modulator and a phase trajectory converter to approximate M=4, h=1/4 continuous phase signal and allows low cost, low complexity, and high rate (>1 Gbit/s) CPM modem implementation for bandwidth efficient transmission through nonlinear satellite channels. Using a communications analysis computer program it has been found that CPQPSK has 99 percent out-of-band power of 0.8R (MSK has 99 percent out-of-band power of 1.2 R where R is defined as bit rate), continuous phase trajectories, and nearly constant envelope amplitude. Simulation of realistic hardware designs indicate that the CPQPSK will require an Eb/No of 14 dB to achieve a bit error rate (BER) of 10^-6. Forward error correcting techniques using block codes with an overhead of 10 percent indicate that the Eb/No requirements can be reduced to 11.2 dB for 10^-6 BER     

Mass transfer across wind-sheared interfaces

A predictive analogy of turbulent mass transfer across wavy, sheared air-water interface, in deep water bodies is proposed. The theory is based on the formulation of a theoretical eddy diffusivity profile in the surface region, and it applies to the non-breaking wave regime. The predictions for a water-side friction velocity range of 0.5–6 cm/s are in excellent agreement with laboratory data from wind-wave facilities with an average error of 15.4%.     

Perceived equity and intimacy in marriage

The extent to which perceived inequity is related to perceived marital intimacy was examined. Sixty-six couples married five years or less were randomly selected from marriage license records in a western rural community. Equity/inequity was assessed using the Walster global measure of equity. Levels of overall intimacy, conflict resolution, affection, cohesion, sexuality, identity, compatibility, autonomy, and expressiveness were measured using the Waring Intimacy Questionnaire (WIQ). Inequity was associated with lower levels of overall intimacy, compatibility, identity, and expressiveness among the wives. Among the husbands, inequity was not associated with any types of intimacy. When comparing husbands in inequitable relationships to wives in inequitable relationships, the wives reported lower scores for only one kind of intimacy--identity. Explanations and implications for marriage therapy are discussed.     

Controlled oxygen incorporation in indium gallium arsenide and indium phosphide grown by metalorganic vapor phase epitaxy

The defect engineering in metalorganic vapor phase epitaxy In_xGa_1-xAs and InP by controlled oxygen doping using diethyl aluminum ethoxide (DEALO) was developed in this study. DEALO doping has led to the incorporation of Al and O, and the compensation of shallow Si donors in In_xGa_1−xAs: Si with 0 ≤ x ≤ 0.25. With the same DEALO mole fraction during growth, the incorporation of Al and O was found to be independent of x, but the compensation of Si donors decreases with increasing In content. Deep level transient spectroscopy analysis on a series of In_xGa_1-xAs: Si. samples with 0 ≤ x ≤ 0.18 revealed that oxygen incorporation led to a set of deep levels, similar to those found in DEALO doped GaAs. As the In composition was increased, one or more of these deep levels became resonant with the conduction band and led to a high electron concentration in oxygen doped In_0.53Ga_0.47As. Low temperature photoluminescence emission measurements at 12K on the same set of samples revealed the quenching of the near-band edge peak, and the appearance of new oxygen-induced emission features. DEALO doping in InP has also led to the incorporation of Al and O, and the compensation of Si donors due to oxygen-induced multiple deep levels.     

The flagship is dropping behind the fleet [UK telecommunicationindustry]

Following privatisation in 1984, BT was mainly preoccupied with customer service, operating costs and business exploitation. BT, its competitors and the industry regulators now have to address major new network issues. Their success in meeting the challenges of the new technologies will have a major impact on the future of UK telecommunications equipment manufacturers. The author takes a hard look at the facts. He argues that duplicating local telecommunications plant is a mistake and should stop; price cap regulation produces the wrong result; and an authoritative engineering agency is needed to co-ordinate technology nationally     

Ultrafast Spectroscopy of La2−x Sr x CuO4 Single Crystals

We present measurements of the ultrafast optical response of La_2–x Sr _x CuO₄ single crystals at two different doping levels (x=0.15, 0.07) as a function of temperature. Owing to the 40-fs time resolution of our experiment, we are able to measure both the build-up and the decay of the ultrafast signal. We show for the first time that the temperature dependence of the transient reflectance amplitude tracks the thermal depletion of the superfluid density. At low temperature we identify a new regime characterized by an extremely long, temperature-dependent rise-time (3 ps). The doping dependence of the relaxation rate suggests that this is sensitive to the scattering of quasiparticles by low-energy spin excitations.     

Performance Metrics for Information Security Risk Management

Qualitative methods are available for risk management, but better practice would use quantitative risk management based on expected losses and related metrics. Measuring the success of information security investments is best accomplished by measuring reductions in expected loss.