A fully monolithic 260-/spl mu/W, 1-GHz subthreshold low noise amplifier

A micro-power complementary metal oxide semiconductor (CMOS) low-noise amplifier (LNA) is presented based on subthreshold MOS operation in the GHz range. The LNA is fabricated in an 0.18-/spl mu/m CMOS process and has a gain of 13.6 dB at 1 GHz while drawing 260 /spl mu/A from a 1-V supply. An unrestrained bias technique, that automatically increases bias currents at high input power levels, is used to raise the input P1dB to -0.2 dBm. The LNA has a measured noise figure of 4.6 dB and an IIP3 of 7.2 dBm.     

S matrix of slot-coupled H-plane tee junctionusing rectangular waveguides

Complex scattering matrix parameters of a slot-coupled, waveguide tee junction are determined using a moment method of analysis with entire orthogonal basis functions and a rigorous analysis of the effect of wall thickness. The variations of the equivalent network parameter, coupling, and return loss with frequency are evaluated, and the results are compared with experimental data. The unitary property of the S matrix is verified. The dependence of coupling on slot length, slot width, and thickness is presented     

Path delay fault simulation of sequential circuits

A differential algorithm for concurrent simulation of path delay faults in sequential circuits is presented. The simulator analyzes all three conditions, namely, initialization, signal transition propagation through the path, and fault effect observation at a primary output for vector pairs and considers the hazard states occurring between vectors. The main contribution is in methods of propagating signals between time frames. An optimistic method assumes that all nondestination flip-flops are not affected by delays. The pessimistic method converts all nondestination flip-flops with nonsteady values to the unknown state before these values are propagated beyond the time frame in which a path is activated. A 13-valued algebra is shown to improve the efficiency of fault simulation     

RHEOLOGICAL EVALUATION OF MOZZARELLA CHEESE BY UNIAXIAL HORIZONTAL EXTENSION

Rheological properties of low-moisture part-skim Mozarella cheese were evaluated as a function of storage time, test temperature, and deformation rate by uniaxial extension in a horizontal plane. Proteolysis of Mozzarella cheese caused marked decreases in the tensile strength and the deformability modulus, but not in the fracture strain. As the temperature increased from 10 to 40C, the fracture strain increased more than five-fold. The strength and the deformability modulus decreased about 60 and 85%, respectively, as the cheese temperature increased from 10 to 30C. The fracture strain of the cheese did not exhibit a clear trend with the deformation rate in the range of 50–500 mm/min. However, its strength and deformability modulus increased with the increasing deformation rate.     

An efficient algorithm for solving general periodic Toeplitzsystems

An efficient algorithm is presented for inverting matrices which are periodically Toeplitz, i.e., whose diagonal and subdiagonal entries exhibit periodic repetitions. Such matrices are not per symmetric and thus cannot be inverted by Trench's (1964) method. An alternative approach based on appropriate matrix factorization and partitioning is suggested. The algorithm provides certain insight on the formation of the inverse matrix, is implementable on a set of circularly pipelined processors and, as a special case, can be used for inverting a set of block Toeplitz matrices without requiring any matrix operation     

Analysis and Optimization of an Adaptive Selective-Repeat Scheme for Time-Varying Channels with Feedback Errors

In this article, an adaptive SR ARQ scheme is analyzed and optimized in a time-varying channel environment with unreliable feedback. Two-state Markov models are assumed for both the forward and the returnchannel.This enables the time behaviour of the entire system to be modelledby a Markov chain. To have an easy-to-implement scheme, we choose the smaller packet size to be half of the bigger one. Thus, there is only oneindependent design parameter related to packet size. The other two parametersare associated with channel sensing. The performance of the adaptive schemeis measured by its average throughput, which is upper-bounded by the throughput of the so-called ideal adaptive scheme. This upper bound is very useful in the optimization of the packet size and other design parameters. From the results, it can be concluded that the selection of the packet size is at least as critical as the optimization of the other parameters. The feedback errors degrade the throughput of the scheme, but their effect on the parameter optimization turns out to be almost negligible.     

4D Printing of Shape Memory Materials for Textiles: Mechanism,Mathematical Modeling,and Challenges

Shape memory materials (SMMs) in 3D printing (3DP) technology garnered much attention due to their ability to respond to external stimuli, which direct this technology toward an emerging area of research, “4D printing (4DP) technology.” In contrast to classical 3D printed objects, the fourth dimension, time, allows printed objects to undergo significant changes in shape, size, or color when subjected to external stimuli. Highly precise and calibrated 4D materials, which can perform together to achieve robust 4D objects, are in great demand in various fields such as military applications, space suits, robotic systems, apparel, healthcare, sports, etc. This review, for the first time, to the best of the authors’ knowledge, focuses on recent advances in SMMs (e.g., polymers, metals, etc.) based wearable smart textiles and fashion goods. This review integrates the basic overview of 3DP technology, fabrication methods, the transition of 3DP to 4DP, the chemistry behind the fundamental working principles of 4D printed objects, materials selection for smart textiles and fashion goods. The central part summarizes the effect of major external stimuli on 4D textile materials followed by the major applications. Lastly, prospects and challenges are discussed, so that future researchers can continue the progress of this technology.     

Aperture Field Estimation in E Plane and H-Plane T-Junctions Using Field Theoretic Analysis

Wireless Personal Communications - This paper presents method of moment based analysis of E Plane and H-Plane T-junctions to find the field distributions on different transverse and longitudinal...     

A Distributed Routing Method for Dynamic Multicasting

Single point, sender based control does not scale well for multicast delivery. For applications, such as group video or teleconferencing a low total cost multicast tree is required. In this article we present a destination driven algorithm to minimize the total tree cost of multicast tree in a dynamic situation for the whole session duration. In this heuristic approach we considered the staying duration of participants are available at the time of joining. The performance of our algorithm is analyzed through extensive simulation and evaluated against several other existing dynamic multicast routing and also against one well known near optimum heuristic algorithm used for solving Steiner tree problem. We have further tested our algorithm using erroneous information given by the joining participants. Simulation results show that its performance does not degrade that much even when the range of error is considerably high, which proves the robustness of our algorithm.