Non-trivial stably free modules over crossed products

We consider the class of crossed products of noetherian domains with universal enveloping algebras of Lie algebras. For algebras from this class we give a sufficient condition for the existence of projective non-free modules. This class includes Weyl algebras and universal envelopings of Lie algebras, for which this question, known as noncommutative Serre's problem, was extensively studied before. It turns out that the method of lifting of non-trivial stably free modules from simple Ore extensions can be applied to crossed products after an appropriate choice of filtration. The motivating examples of crossed products are provided by the class of RIT algebras, originating in non-equilibrium physics.

MODULATED BACKSCATTER MICROWAVE SECURITY SENSOR

A system capable of deployment as a microwave security sensor which can automatically reject background clutter is presented. The principle of operation is based on analog homodyne detection using 1. Q single side-band down conversion of an AM backscattered modulating signal envelope. A demonstrator is presented which operates with a carrier frequency of 2 GHz and 500 KHz backscattered signal. When deployed in a multipath rich open plan office environment the S/N ratio obtained at the detection output was better than 20 dB at 20 in range with 20 dBm EIRP in a 2 MHz detection bandwidth despite the presence of time varying and static clutter. (C) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2492-2495, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24636

Trust considerations on attitudes towards online purchasing: The moderating effect of privacy and security concerns

The research examines the relationships between three common trust considerations (vendor, Internet and third parties) and attitudes towards online purchasing. The study incorporates privacy and security concerns as a moderating variable and finds that these relationships vary depending on the level of concerns a consumer has when purchasing online. The study suggests that "fears" surrounding the Internet as a place to do business still hinder the use of it for e-commerce purposes, but that the presence of a reputable agent might in some manner mitigate this risk. In the context of business to consumer relationships trust in the vendor is important for the consumer to accept any risk associated with a transaction. Theoretical implications for online customer behavior theory are also discussed. © 2009 Elsevier Inc.