Software Assisted Digital RF Processor (DRP™) for Single-Chip GSM Radio in 90 nm CMOS

This paper proposes and describes a new software and application programming interface view of an RF transceiver. It demonstrates benefits of using highly programmable digital control logic in an RF wireless system realized in a digital nanoscale CMOS process technology. It also describes a microprocessor architecture design in Digital RF Processor (DRP™) and how it controls calibration and compensation for process, temperature and voltage variations of the analog and RF circuits to meet the required RF performance. A few calibration examples to reduce a DCO bias current and improve device reliability, as well as to optimize transmit modulation and receive performance, are given. The presented circuits and techniques have enabled successful implementation of a commercial single-chip GSM radio in 90 nm CMOS.      

Protein kinase C regulation of ATP-induced phosphoinositide hydrolysis in bovine aorta endothelial cells

This study investigated the mechanism of protein kinase C-mediated inhibition of ATP-induced phospholipase C activation in cultured bovine aorta endothelial cells (BAEC). In BAEC labeled with 3H-inositol, phorbol myristate acetate (PMA) prevented ATP-induced inositol bisphosphate and inositol trisphosphate formation. In membranes prepared from these PMA-treated cells, Ca(2+)-, sodium fluoride-, GTP gamma S-, and ATP plus GTP gamma S-stimulated inositol bisphosphate, but not inositol trisphosphate, formation was inhibited. Inositol trisphosphate phosphatase activity was not altered in membranes from PMA-treated BAEC. These results suggest that 1) protein kinase C inhibits ATP-induced phospholipase C activation in BAEC through interference with the coupling of phospholipase C with a G-protein and through an effect on phospholipase C itself, and 2) different mechanisms are responsible for the inhibition by protein kinase C of the phospholipase C-mediated hydrolysis of phosphatidylinositol bisphosphate and phosphatidyl-inositol phosphate.     

A Crame/spl acute/r-Rao-type estimation lower bound for systems with measurement faults

A Crame/spl acute/r-Rao-type lower bound is presented for systems with measurements prone to discretely-distributed faults, which are a class of hybrid systems. Lower bounds for both the state and the Markovian interruption variables (fault indicators) of the system are derived, using the recently presented sequential version of the Crame/spl acute/r-Rao lower bound (CRLB) for general nonlinear systems. Because of the hybrid nature of the systems addressed, the CRLB cannot be directly applied due to violation of its associated regularity conditions. To facilitate the calculation of the lower bound, the hybrid system is first approximated by a system in which the discrete distribution of the fault indicators is replaced by an approximating continuous one. The lower bound is then obtained via a limiting process applied to the approximating system. The results presented herein facilitate a relatively simple calculation of a nontrivial lower bound for the state vector of systems with fault-prone measurements. The CRLB-type lower bound for the interruption process variables turns out to be trivially zero, however, a nontrivial, non-CRLB-type bound for these variables has been recently presented elsewhere by the authors. The utility and applicability of the proposed lower bound are demonstrated via a numerical example involving a simple global positioning system (GPS)-aided navigation system, where the GPS measurements are fault-prone due to their sensitivity to multipath errors.     

Gain control and diffraction-managed solitons in metamaterials

The question of whether stable, active metamaterials can be created is addressed, both through a discussion of absolute instability and an analysis of a transmission line that produces dispersion analogous to that of the familiar split-ring resonator/wire-based metamaterial. The gain is introduced using negative conductance diodes and it is shown that the frequency bandwidth controls the stability window. The diodes are located as lumped elements in the unit cell. It is demonstrated that the production of an, active, negative phase (left-handed) frequency window, with spatial amplification is possible. The paper then goes on to assume that since loss can be controlled in this way special types of solitons can be created from phase and loss compensation and they could be the basis of future computational devices. The candidates selected are diffraction-managed spatial solitons and their basic properties are displayed numerically.     

Answering atomic queries in indefinite deductive databases

Answering queries in indefinite systems is a difficult problem both computationally, since it involves non-Horn clauses and factoring, and conceptually, concerning producing beliefs for formulas not derivable from the system. to provide a basis for reasonable beliefs, we propose new criteria as an alternative to the Full Information Principle. Then an approach to producing stable beliefs, called Plausible World Assumption (PWA), is introduced. It is shown how a set of non-Horn clauses can be transformed into a set of so called singleton-head-rules such that evaluation of a given query is reduced to processing of a set of Horn clauses relevant to the query. Finally, algorithms are presented for computing facts and beliefs for atomic queries in accord with the PWA. This method is shown to be more efficient than the known techniques for query evaluation in indefinite systems.     

The Perception Of Urban Complexity

The concept of complexity is denned in terms of urban perception. The definition is based on a concept of maximum rate of usable information, which allows for the social and cultural setting as well as for learning. The desirability of complexity and its achievement are suggested in two propositions that may be used as a basis for future environmental research and design applications.     

The Sleep Heart Health Study: design, rationale, and methods

The Sleep Heart Health Study (SHHS) is a prospective cohort study designed to investigate obstructive sleep apnea (OSA) and other sleep-disordered breathing (SDB) as risk factors for the development of cardiovascular disease. The study is designed to enroll 6,600 adult participants aged 40 years and older who will undergo a home polysomnogram to assess the presence of OSA and other SDB. Participants in SHHS have been recruited from cohort studies in progress. Therefore, SHHS adds the assessment of OSA to the protocols of these studies and will use already collected data on the principal risk factors for cardiovascular disease as well as follow-up and outcome information pertaining to cardiovascular disease. Parent cohort studies and recruitment targets for these cohorts are the following: Atherosclerosis Risk in Communities Study (1,750 participants), Cardiovascular Health Study (1,350 participants), Framingham Heart Study (1,000 participants), Strong Heart Study (600 participants), New York Hypertension Cohorts (1,000 participants), and Tucson Epidemiologic Study of Airways Obstructive Diseases and the Health and Environment Study (900 participants). As part of the parent study follow-up procedures, participants will be surveyed at periodic intervals for the incidence and recurrence of cardiovascular disease events. The study provides sufficient statistical power for assessing OSA and other SDB as risk factors for major cardiovascular events, including myocardial infarction and stroke.     

Corrosion and oxidation of alloys of the Mg-Y-Zr-REM system

The corrosion resistance of an alloy of the Mg-Y-Zr-REM system obtained by sand casting and subjected to different modes of heat treatment is studied with the use of potentiodynamic polarization, immersion tests, scanning electron microscope, and Auger electron spectroscope. The microstructure of the alloy is described.