Error floor of MSK modulation in a mobile-radio channel with twoindependently fading paths

We investigate the error probability bit error rate (BER) of minimum shift keying (MSK) modulation with differential detection in a two-path fading channel without noise (error floor). We develop a new method for the computation of the BER: we show that errors occur if the phasors of the instantaneous impulse response fall into certain regions of the complex plane; then we average over the statistics of the phasors to arrive at the mean BER. With this method, we derive analytical expressions for the BER for arbitrary amplitude statistics of the paths. For the special case of two Rayleigh-fading paths with small delay, we find that the BER is proportional to the square of the mean delay spread (normalized to the bit length) if we sample between the two pulses. This proves the qualitative behavior of previous estimates, but our results allow also a more exact quantitative formulation. The quadratic dependence of the BER on the delay spread breaks down if we have one Rayleigh-fading and one Rician-fading path. We find that the bit combinations 1-11 and -11-1 do not lead to errors in the two-path model. However, additional Monte Carlo simulations show that these bit combinations do lead to errors in a three-path model     

Rotating magnetic field-driven flows in conductive inhomogeneous media: Part I—Numerical study

This paper presents a numerical study of the Lorentz force and fluid flow induced by a rotating magnetic field in a medium with a nonhomogeneous electric conductivity placed in a cylindrical vessel with insulated walls. The nonhomogeneity is modeled by the presence of a solid and a liquid phase of different electrical conductivity. The solid phase is located orthogonally to the axis of rotation, which corresponds to the case of unidirectional solidification. The simulations were performed for different locations of the solid front and different ratios of the electrical conductivity, σ _s /σ _l =0.2... 10. Here σ _s and σ _l are the electric conductivity of the solid and liquid phases, respectively. The results showed that the difference between electrical conductivity of solid and liquid phases has a noticeable effect on the mean-time Lorentz force and the velocity: namely, the presence of the solid phase (σ _s >σ _l ) leads to an increase of the Lorentz force and fluid flow in the cylinder.     

Retrenchment management: coping with fewer tax dollars

Since the early 1970s, local governments in the USA have faced limited tax income combined with double-digit inflation. As a result, every local service from fire prevention to recreation has had to be closely scrutinized. Local administrators and politicians have evolved new and innovative retrenchment management policies to respond to both the demands of citizens and the fewer dollars available. A combination of denial of new programmes and public sector pay austerity, with public education and use of community organizations is providing ways to stretch limited funds. The reality in many communities across the USA is that local government and its services will not be growing in the future.     

Role of construal processes in conformity and dissent.

Develops 3 hypotheses to explain the role of construal processes in conformity behavior. According to the preconformity change of meaning hypothesis, social influence leads to changes in situational construal that precede and mediate conformity behavior; according to the postconformity change of meaning hypothesis, construal change follows and justifies conformity; and according to the construal-consistency hypothesis, preexisting situational construal distinguishes those who conform from those who dissent. Four experimental studies with varying methodology and involving a total of 361 undergraduate students were performed to test these hypotheses. The results of all studies provide strong evidence for postconformity change of meaning effects. Discussion centers on possible domains in which the different construal mechanisms might operate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Natural zeolite utilisation in pollution control: A review of applications to metals' effluents

This paper assesses the potential of natural zeolite utilization as a low-cost ion-exchange and sorbent material in pollution control and recovery of metals. The improvement of the purity of natural zeolites coupled with their chemical modification capabilities in order to provide specific properties may provide a cost-effective alternative for the treatment of heavy metal contaminated soil and water. The application of natural zeolites in industrial pollution control is becoming important and the level of technical effort is increasingly expanding. The extent of application is unlikely to be related solely to their low cost, but also to improved properties and performance characteristics, which will advance the practical implementation of natural zeolites' technology.     

Characterization of solid state array cameras for the mid-IR

We present a characterization of some processes affecting the performance of solid state array cameras designed for ground based astronomical imaging in the 8–13μm atmospheric window. Our discussion includes a novel model for electron-hole generationrecombination noise based on the probable pathlength of an electron in a photoconductor. We use the Berkeley mid-IR Array Camera as an example. For this camera, the results show that the total optical system composed of the camera, a 3m telescope, and the atmosphere has an efficiency of about 3%, a 1σ noise equivalent flux density of 25 mJy min^?1/2arcsec^?2 measured over a Δλ/λ=10% band width, and a noise equivalent expressed as the ambient temperature thermal black body noise of 23%.