A Combined Antenna Array and Multi-User Detection DS-CDMA Receiver in Single-Path and Multi-Path Fading Channels

An adaptive antenna array is incorporated into a decorrelatingmulti-user detector to effectively increase the DS-CDMA system capacity.Capacity improvement is due to beamforming gain, spatial diversity gain(assuming large angle spread), and the decorrelating effect. Thereceiver has been analyzed for the cases of sufficiently andinsufficiently spaced receiving antennas. The receiver consists of afront-end beamformer for every user in the cell and has knowledge of allusers' signature sequences. The beamformer estimates the desired userchannel vector, enhancing its signal and reducing the co-channelinterference from other directions. The multi-user detection, exploitingknowledge of other users, rejects those interferers whose arrival anglesare close to that of the desired user. The average uncoded Bit ErrorRate (BER) as a function of the number of in-beam active users, theaverage antenna Signal-to-Noise Ratio (SNR), and the number of receivingantennas is examined in both single-path and multi-path Rayleigh fadingchannels. Analysis shows an increase in system capacity proportional tothe number of receiving antennas.     

Broad-band pulse performance of short helices

Helical antennas are popular and well characterized for CW frequency domain performance. Renewed interest in time-domain applications of electromagnetics, such as impulse radar, makes accurate time-domain data on broad-band antennas desirable. Although the principal endfire helix radiation mode has been extensively studied in the frequency domain, other modes important in pulse operation are poorly characterized, making a total Fourier transform approach difficult. We have performed impulse tests on helices with two to five turns, establishing novel features of the response and confirming some aspects of frequency domain data. Quick comparisons to time and frequency-domain modeling codes indicate good correspondence of gross features. Successful octave band-pulse operation was achieved, and a few features of helix pulse response invite further investigation     

Characterization of Apo-Form Selective Inhibition of Indoleamine 2,3-Dioxygenase**

Indoleamine-2,3-dioxygenase 1 (IDO1) is a heme-containing enzyme that catalyzes the rate-limiting step in the kynurenine pathway of tryptophan (TRP) metabolism. As it is an inflammation-induced immunoregulatory enzyme, pharmacological inhibition of IDO1 activity is currently being pursued as a potential therapeutic tool for the treatment of cancer and other disease states. As such, a detailed understanding of the mechanism of action of IDO1 inhibitors with various mechanisms of inhibition is of great interest. Comparison of an apo-form-binding IDO1 inhibitor (GSK5628) to the heme-coordinating compound, epacadostat (Incyte), allows us to explore the details of the apo-binding inhibition of IDO1. Herein, we demonstrate that GSK5628 inhibits IDO1 by competing with heme for binding to a heme-free conformation of the enzyme (apo-IDO1), whereas epacadostat coordinates its binding with the iron atom of the IDO1 heme cofactor. Comparison of these two compounds in cellular systems reveals a long-lasting inhibitory effect of GSK5628, previously undescribed for other known IDO1 inhibitors. Detailed characterization of this apo-binding mechanism for IDO1 inhibition might help design superior inhibitors or could confer a unique competitive advantage over other IDO1 inhibitors vis-à-vis specificity and pharmacokinetic parameters.     

A Low-Cost Checkpointing Technique for Distributed Databases

For distributed databases, checkpointing is used to ensure an efficient way to perform global reconstruction. However, the need for global reconstruction is infrequent. Most current checkpointing approaches for distributed databases are too expensive during run time. Some of them allow the checkpointing process to run in parallel with normal transactions at the cost of more data and resource contention, which in turn causes longer response time for normal transactions. Thus, an efficient way to checkpoint distributed databases is needed to avoid degrading the system performance. This paper presents a low-cost solution, called Loosely Synchronized Local Fuzzy Checkpointing (LSLFC), to these problems. LSLFC supports global reconstruction, and our performance study shows that LSLFC has little overhead during run time.     

Common subexpression processing in multiple-query processing

The efficiency of common subexpression identification is critical to the performance of multiple-query processing. In this paper, we develop a multigraph for representing and facilitating the processing of multiple queries. In addition to the traditional multiple-query processing approaches in exploiting common subexpressions for identical and subsumption cases, the proposed multigraph processing also covers the overlap case. A performance study shows the viability of this technique when compared to an earlier multigraph approach     

Simulation of Dynamic Earthquake Ruptures in Complex Geometries Using High-Order Finite Difference Methods

We develop a stable and high-order accurate finite difference method for problems in earthquake rupture dynamics in complex geometries with multiple faults. The bulk material is an isotropic elastic solid cut by pre-existing fault interfaces that accommodate relative motion of the material on the two sides. The fields across the interfaces are related through friction laws which depend on the sliding velocity, tractions acting on the interface, and state variables which evolve according to ordinary differential equations involving local fields. The method is based on summation-by-parts finite difference operators with irregular geometries handled through coordinate transforms and multi-block meshes. Boundary conditions as well as block interface conditions (whether frictional or otherwise) are enforced weakly through the simultaneous approximation term method, resulting in a provably stable discretization. The theoretical accuracy and stability results are confirmed with the method of manufactured solutions. The practical benefits of the new methodology are illustrated in a simulation of a subduction zone megathrust earthquake, a challenging application problem involving complex free-surface topography, nonplanar faults, and varying material properties.     

Lipid biophysics and/or soft matter-inspired approach for controlling enveloped virus infectivity

Proven as a natural barrier against viral infection, pulmonary surfactant phospholipids have a biophysical and immunological role within the respiratory system, acting against microorganisms including viruses. Enveloped viruses have, in common, an outer bilayer membrane that forms the underlying structure for viral membrane proteins to function in an optimal way to ensure infectivity. Perturbating the membrane of viruses using exogenous lipids can be envisioned as a generic way to reduce their infectivity. In this context, the potential of exogenous lipids to be used against enveloped virus infectivity would be indicated by the resulting physical stress imposed to the viral membrane, and conical lipids, i.e. lyso-lipids, would be expected to generate stronger biophysical disturbances. We confirm that when treated with lyso-lipids the infectivity three strains of influenza virus (avian H2N3, equine H3N8 or pandemic human influenza H1N1) is reduced by up to 99% in a cell-based model. By contrast, lipids with a similar head group but two aliphatic chains were less effective (reducing infection by only 40–50%). This work opens a new path to merge concepts from different research fields, i.e. ‘soft matter physics'' and virology.     

Evaluation of calculational and material models for concrete containment structures

A computer code utilizing an appropriate finite element, material and constitutive model has been under development as a part of a comprehensive effort by the Electric Power Research Institute (EPRI) to develop and validate a realistic methodology for the ultimate load analysis of concrete containment structures. A preliminary evaluation of the reinforced and prestressed concrete modeling capabilities recently implemented in the ABAQUS-EPGEN code has been completed. This effort focuses on using a state-of-the-art calculational model to predict the behavior of large-scale reinforced concrete slabs tested under uniaxial and biaxial tension to simulate the wall of a typical concrete containment structure under internal pressure. This paper gives comparisons between calculations and experimental measurements for a uniaxially-loaded specimen. The calculated strains compare well with the measued strains in the reinforcing steel; however, the calculations gave diffused cracking patterns that do not agree with the discrete cracking observed in the experiments. Recommendations for improvement of the calculational models are given.     

Performance Bounds for Convolutional Codes with Digital Viterbi Decoders in Gaussian Noise

With digital implementations of the Viterbi decoding algorithm for convolutional codes, soft quantization is preferred over hard quantization because it generally yields superior performance. Since the decoder needs to know the signal energy and channel noise variance with soft quantization, inaccurate information can result in a mismatch between the channel and decoder. Bounds which are tight for high signal-to-noise ratios are obtained on the bit error probability using the generating function approach. Automatic gain control level inaccuracies, imperfect carrier phase, symbol timing synchronization error, and path metric digitization are discussed in the context of a mismatch between the channel and decoder.     

Reports for 1982 of the Regional Associations.

Reports for 1982 are listed for the following regional association meetings: Sixty-Second Annual Meeting of the Western Psychological Association; Fifty-Second Annual Meeting of the Rocky Mountain Psychological Association; Fifty-Fourth Annual Meeting of the Midwestern Psychological Association; Twenty-Eighth Annual Meeting of the Southeastern Psychological Association; Twenty-Eighth Annual Meeting of the Southwestern Psychological Association; Twenty-Second Annual Meeting of the New England Psychological Association; Fifty-Third Annual Meeting of the Eastern Psychological Association; and Seventy-Fourth Annual Meeting of the Southern Society for Philosophy and Psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)