Provisos for classic linear oscillator design methods. New linear oscillator design based on the NDF/RRT

In this paper, the classic oscillator design methods are reviewed, and their strengths and weaknesses are shown. Provisos for avoiding the misuse of classic methods are also proposed. If the required provisos are satisfied, the solutions provided by the classic methods (oscillator start-up linear approximation) will be correct. The provisos verification needs to use the NDF (Network Determinant Function). The use of the NDF or the most suitable RRT (Return Relation Transponse), which is directly related to the NDF, as a tool to analyze oscillators leads to a new oscillator design method. The RRT is the "true" loop-gain of oscillators. The use of the new method is demonstrated with examples. Finally, a comparison of NDF/RRT results with the HB (Harmonic Balance) simulation and practical implementation measurements prove the universal use of the new methods

Dual-Frequency Printed Dipole Loaded With Split Ring Resonators

A novel approach to design dual- frequency printed dipoles is presented. This approach is based on an antipodal printed dipole loaded with split ring resonators (SRRs). This technique allows the choice of any pair of working frequencies. Two prototypes, the first one working at 1.32 and 2.83 GHz and the second one working at 1.2 and 2.05 GHz, have been manufactured and measured. The experimental results show reasonable values for the efficiency at both working frequencies. Moreover, the obtained radiation pattern is dipolar at both frequencies with low cross polarization levels

Design of a Compact Dual-Circular-Polarized Cavity-Backed Spiral Antenna

In this paper, a dual-circular-polarized antenna is presented. The compactness of the design is the greatest contributionof this work, achieving dual circular polarizationwith a single antenna. The design is based on a four-armspiral with differential feeding to achieve the desired polarization. The antenna achieves a bandwidth of 60% (from 4 to 7.5 GHz) for an axial ratio below 3 dB, return losses below-8 dB and isolation below -30 dB. Symmetric radiationpattern with gain higher than 7 dB is obtained

A Compact Design for Dual-band Implantable Antenna Applications

This paper presents the development of a dual-band antenna working in the Industrial, Scientific, and Medical (ISM) band (902 – 928 MHz, 2.4 – 2.5 GHz). The proposed antenna is compact, has a frequency-independent response between the lowest and the highest frequency, has a small size of 6 x 6 x 2.54 mm3. This design does not use any via or defected ground plane making the antenna very useful for this kind of application

A method to classify digital images by means of statistics of a wavelet decomposition

There is a wide variety of methods for the analysis of textures and the extraction of image characteristics based on wavelet decomposition. The objective of this paper is to find a vector of characteristics of each image and to determine a classification among them using principal component analysis. The procedures presented here are for classifying test images. After fragmenting the image, a wavelet decomposition of the fragmented images is performed both in scale and in orientation. To characterize the images, statistics of marginal and joint distributions based on local neighborhoods of spatial, orientation and scale type are used

A method to classify digital images by means of statistics of a wavelet decomposition

There is a wide variety of methods for the analysis of textures and the extraction of image characteristics based on wavelet decomposition. The objective of this paper is to find a vector of characteristics of each image and to determine a classification among them using principal component analysis. The procedures presented here are for classifying test images. After fragmenting the image, a wavelet decomposition of the fragmented images is performed both in scale and in orientation. To characterize the images, statistics of marginal and joint distributions based on local neighborhoods of spatial, orientation and scale type are used

Development of a Randomized Trial Comparing ICP-Monitor-Based Management of Severe Pediatric Traumatic Brain Injury to Management Based on Imaging and Clinical Examination Without ICP Monitoring-Research Algorithms

BACKGROUND AND OBJECTIVES: The efficacy of our current approach to incorporating intracranial pressure (ICP) data into pediatric severe traumatic brain injury (sTBI) management is incompletely understood, lacking data from multicenter, prospective, randomized studies. The National Institutes of Health-supported Benchmark Evidence from Latin America-Treatment of Raised Intracranial Pressure-Pediatrics trial will compare outcomes from pediatric sTBI of a management protocol based on ICP monitoring vs 1 based on imaging and clinical examination without monitoring. Because no applicable comprehensive management algorithms for either cohort are available, it was necessary to develop them. METHODS: A consensus conference involving the 21 intensivists and neurosurgeons from the 8 trial sites used Delphi-based methodology to formulate management algorithms for both study cohorts. We included recommendations from the latest Brain Trauma Foundation pediatric sTBI guidelines and the consensus-based adult algorithms (Seattle International Brain Injury Consensus Conference/Consensus Revised Imaging and Clinical Examination) wherever relevant. We used a consensus threshold of 80%. RESULTS: We developed comprehensive management algorithms for monitored and nonmonitored cohort children with sTBI. We defined suspected intracranial hypertension for the nonmonitored group, set minimum number and timing of computed tomography scans, specified minimal age-adjusted mean arterial pressure and cerebral perfusion pressure targets, defined clinical neuroworsening, described minimal requisites for intensive care unit management, produced tiered management algorithms for both groups, and listed treatments not routinely used. CONCLUSION: We will study these protocols in the Benchmark Evidence from Latin America-Treatment of Raised Intracranial Pressure-Pediatrics trial in low- and middle-income countries. Second, we present them here for consideration as prototype pediatric sTBI management algorithms in the absence of published alternatives, acknowledging their limited evidentiary status. Therefore, herein, we describe our study design only, not recommended treatment protocols.Fogarty International CenterRevisión por pare