5,200 research outputs found

    Position location and data collection system and method Patent

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    Development of telemetry system for position location and data acquisitio

    The analysis of reactively loaded microstrip antennas by finite difference time domain modelling

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    In recent years, much interest has been shown in the use of printed circuit antennas in mobile satellite and communications terminals at microwave frequencies. Although such antennas have many advantages in weight and profile size over more conventional reflector/horn configurations, they do, however, suffer from an inherently narrow bandwidth. A way of optimizing the bandwidth of such antennas by an electronic tuning technique using a loaded probe mounted within the antenna structure is examined, and the resulting far-field radiation patterns are shown. Simulation results from a 2D finite difference time domain (FDTD) model for a rectangular microstrip antenna loaded with shorting pins are given and compared to results obtained with an actual antenna. It is hoped that this work will result in a design package for the analysis of microstrip patch antenna elements

    Remote detection of aerosol pollution by ERTS

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    Photogrammetric and densitometric examination of ERTS-1 MSS imagery of Eastern Virginia coupled with extensive ground truth air quality and meteorological data has shown that the identification and surveying of fixed particulate emitters (smoke plumes) is feasible. A description of the ground truth network is included. The quantitative monitoring of smoke stacks from orbital altitudes over state size regions appears possible when tied to realistic plume models and minimal ground truth. Contrast reductions over urban areas can possibly be utilized to produce isopleths of particulates when supplemented by local measurements

    Time-division SQUID multiplexers with reduced sensitivity to external magnetic fields

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    Time-division SQUID multiplexers are used in many applications that require exquisite control of systematic error. One potential source of systematic error is the pickup of external magnetic fields in the multiplexer. We present measurements of the field sensitivity figure of merit, effective area, for both the first stage and second stage SQUID amplifiers in three NIST SQUID multiplexer designs. These designs include a new variety with improved gradiometry that significantly reduces the effective area of both the first and second stage SQUID amplifiers.Comment: 4 pages, 7 figures. Submitted for publication in the IEEE Transactions on Applied Superconductivity, August 201

    Optimal General Matchings

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    Given a graph G=(V,E)G=(V,E) and for each vertex v∈Vv \in V a subset B(v)B(v) of the set {0,1,…,dG(v)}\{0,1,\ldots, d_G(v)\}, where dG(v)d_G(v) denotes the degree of vertex vv in the graph GG, a BB-factor of GG is any set F⊆EF \subseteq E such that dF(v)∈B(v)d_F(v) \in B(v) for each vertex vv, where dF(v)d_F(v) denotes the number of edges of FF incident to vv. The general factor problem asks the existence of a BB-factor in a given graph. A set B(v)B(v) is said to have a {\em gap of length} pp if there exists a natural number k∈B(v)k \in B(v) such that k+1,…,k+p∉B(v)k+1, \ldots, k+p \notin B(v) and k+p+1∈B(v)k+p+1 \in B(v). Without any restrictions the general factor problem is NP-complete. However, if no set B(v)B(v) contains a gap of length greater than 11, then the problem can be solved in polynomial time and Cornuejols \cite{Cor} presented an algorithm for finding a BB-factor, if it exists. In this paper we consider a weighted version of the general factor problem, in which each edge has a nonnegative weight and we are interested in finding a BB-factor of maximum (or minimum) weight. In particular, this version comprises the minimum/maximum cardinality variant of the general factor problem, where we want to find a BB-factor having a minimum/maximum number of edges. We present an algorithm for the maximum/minimum weight BB-factor for the case when no set B(v)B(v) contains a gap of length greater than 11. This also yields the first polynomial time algorithm for the maximum/minimum cardinality BB-factor for this case
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