Distributed learning in wireless sensor networks

This paper discusses nonparametric distributed learning. After reviewing the classical learning model and highlighting the success of machine learning in centralized settings, the challenges that wireless sensor networks (WSN) pose for distributed learning are discussed, and research aimed at addressing these challenges is surveyed.     

Lacrimal gland inflammation is responsible for ocular pathology in TGF-beta 1 null mice

Mice homozygous for a nonfunctional transforming growth factor-beta 1 gene develop rampant inflammation in vital organs that contributes to a shortened life span. The presence of circulating anti-nuclear anti-bodies, immune deposits in tissues, leukocyte infiltration, and increased major histocompatibility complex antigen expression resembles an autoimmune-like syndrome. One of the overt symptoms that appears in these mice lacking transforming growth factor-beta 1 is the development of dry crusty eyes that close persistently as their health declines. Histologically, the eyes appear normal with little or no inflammation. However, inflammatory lesions, predominantly lymphocytic, develop in the lacrimal glands, disrupting their structure and function and severely limiting their ability to generate tears. This histopathology and aberrant function mimic that of Sj?gren's syndrome, a human autoimmune disease characterized by dry eyes and dry mouth. Impeding the leukocyte infiltration into the glands with synthetic fibronectin peptides, which block adhesion, not only prevents the inflammatory pathology but also prevents the persistent eye closure characteristic of these mice.     

Sampling and processing of color signals

Digital signal processing tools are used to determine the proper sampling of color spectra and the effect of sampling on the accuracy of derived properties such as CIE tristimulus values and color rendering indexes. It is found that 10 nm sampling is adequate for most applications, but not for more exacting textile and paint matching applications. Special methods are proposed to treat the cases of color signals with delta function components such as fluorescent lights.     

Model-based reconstruction of multiple circular and ellipticalobjects from a limited number of projections

We consider tomographic image reconstruction from a limited number of noisy projections. An efficient algorithm based on maximum likelihood estimation (MLE) is developed to reconstruct images of multiple discs with unknown locations and radii. The algorithm is successfully applied to images with signal-to-noise ratio (SNR) as low as 0 dB, using as few as 16 projections, and containing as many as twelve discs with widely varying radii. Experimental results show that our approach significantly outperforms conventional convolution back projection. The algorithm is successfully extended to the multiple ellipse case.     

A new formulation for load flow solution of power systems with series FACTS devices

This paper addresses the solution of load flow equations for a power system with series flexible AC transmission systems (FACTS) devices. A novel formulation of equations using dual state variables (current magnitude and angle) and dual control variables (series injected real power and series voltage in quadrature with current) for series devices is proposed. These specifications can be related to transmission line loading and device limits. Specifications like power flow through a series device can also be handled using this formulation. The load flow equations are solved using Newton-Raphson technique. A decoupled formulation is also proposed. Case studies are carried out on IEEE test systems with several types of specifications to validate the method.     

Polynomials for narrowband signal processing

A novel window function series in the form of two-term polynomials suitable for narrow mainlobe width applications is described. The mainlobe width of the polynomial series can assume values between /spl plusmn/1/T to /spl plusmn/1.5/T, where T is the window duration and the asymptotic decay can be either 6dB/octave or 12dB/octave depending on the criterion imposed. The polynomial series has the narrowest mainlobe width of all the windows reported so far, with 12 dB/octave decay of sidelobes. It is shown that, theoretically, the series achieves the mainlobe width of a rectangular window while maintaining the higher decay of sidelobes.     

Synthesis of new light-emitting donor–acceptor materials: Isomers of phenothiazine–quinoline molecules

Highly fluorescent isomeric donor–acceptor molecules, 2-(4-phenyl-2-quinolyl)-10-methylphenothiazine (2PQMPT) and 3-(4-phenyl-2-quinolyl)-10-methylphenothiazine (3PQMPT), were synthesized in high yields (>85%) and found to exhibit a factor of 2.4 disparity in electroluminescence efficiency. Bright (10,000–25,000 cd/m²) and efficient (3.6–8.7 cd/A) green organic light-emitting diodes were realized from the two donor–acceptor molecules. The new molecules are good model systems for the study of structure–property relationships of donor–acceptor molecules for organic light-emitting diodes.     

Network issues for wireless communications

This article specifically focuses on wireless personal communications, i.e., wireless access, that provides either terminal or personal mobility. In particular, we discuss some important issues in networking, traffic, and performance. Although within radio and networking aspects there are significant commonalities between traditional cellular mobile communications and wireless personal communications, there exist distinct differences due to radio propagation and fading effects, interference environment, smaller cell sizes, type and pattern of mobility, and call delivery. Indeed, with respect to networking issues, a large set of system choices, characteristics of traffic to be carried, and important parameters have to be considered. These include the problems involved in selecting an appropriate multiaccess technology to efficiently handle the required subscriber service profile across a multiplicity of systems to complete a call. To present a meaningful discussion of these issues, we address in some detail radio resource assignment, mobility management, call control, and traffic aspect, which have significant impact on the network performance