scholarly journals Dual Feed, Single Element Antenna for WiMAX MIMO Application

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Frank M. Caimi ◽  
Mark Mongomery
Keyword(s):  
Correlation Coefficient ◽  
Performance Metrics ◽  
Measured Data ◽  
Antenna Pattern ◽  
Relative Performance ◽  
Equal Length ◽  
Impedance Match ◽  
Single Element ◽  
Pattern Correlation ◽  
Operating Bandwidth

A novel u-shaped single element antenna having two feed ports is compared with two equal length monopoles separated by a distance equivalent to the width. A discussion of relative performance metrics is provided for MIMO applications, and measured data is given for comparison. Good impedance match and isolation of greater than  dB are observed over the operating bandwidth from 2.3 to 2.39 GHz. The antenna patterns are highly uncorrelated, as illustrated by computation of the antenna pattern correlation coefficient for the two comparison monopoles.

scholarly journals Computation of antenna pattern correlation and MIMO performance by means of surface current distribution and\\ spherical wave theory

2006 ◽  
Vol 4 ◽  
pp. 33-39 ◽  
Author(s):  
O. Klemp ◽  
G. Armbrecht ◽  
H. Eul
Keyword(s):  
Channel Capacity ◽  
Current Distribution ◽  
Spherical Wave ◽  
Surface Current ◽  
Wave Theory ◽  
Antenna Pattern ◽  
Mimo Channel ◽  
Computational Technique ◽  
Surface Current Distribution ◽  
Pattern Correlation

Abstract. In order to satisfy the stringent demand for an accurate prediction of MIMO channel capacity and diversity performance in wireless communications, more effective and suitable models that account for real antenna radiation behavior have to be taken into account. One of the main challenges is the accurate modeling of antenna correlation that is directly related to the amount of channel capacity or diversity gain which might be achieved in multi element antenna configurations. Therefore spherical wave theory in electromagnetics is a well known technique to express antenna far fields by means of a compact field expansion with a reduced number of unknowns that was recently applied to derive an analytical approach in the computation of antenna pattern correlation. In this paper we present a novel and efficient computational technique to determine antenna pattern correlation based on the evaluation of the surface current distribution by means of a spherical mode expansion.

A Novel Hybrid Model for Solar Radiation Forecasting Using Support Vector Machine and Bee Colony Optimization Algorithm: Review and Case Study

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Mawloud Guermoui ◽  
Kacem Gairaa ◽  
John Boland ◽  
Toufik Arrif
Keyword(s):  
Support Vector Machine ◽  
Solar Radiation ◽  
Least Squares ◽  
Correlation Coefficient ◽  
Cuckoo Search ◽  
Measured Data ◽  
Parameters Optimization ◽  
Support Vector ◽  
Bee Colony ◽  
Svm Model

Abstract This article proposes a new hybrid least squares-support vector machine and artificial bee colony algorithm (ABC-LS-SVM) for multi-hour ahead forecasting of global solar radiation (GHI) data. The framework performs on training the least squares-support vector machine (LS-SVM) model by means of the ABC algorithm using the measured data. ABC is developed for free parameters optimization for the LS-SVM model in a search space so as to boost the forecasting performance. The developed ABC-LS-SVM approach is verified on an hourly scale on a database of five years of measurements. The measured data were collected from 2013 to 2017 at the Applied Research Unit for Renewable Energy (URAER) in Ghardaia, south of Algeria. Several combinations of input data have been tested to model the desired output. Forecasting results of 12 h ahead GHI with the ABC-LS-SVM model led to the root-mean-square error (RMSE) equal to 116.22 Wh/m2, Correlation coefficient r = 94.3%. With the classical LS-SVM, the RMSE error equals to 117.73 Wh/m2 and correlation coefficient r = 92.42%; for cuckoo search algorithm combined with LS-SVM, the RMSE = 116.89 Wh/m2 and r = 93.78%. The results achieved reveal that the proposed hybridization scheme provides a more accurate performance compared to cuckoo search-LS-SVM and the stand-alone LS-SVM.

scholarly journals Miniaturized Coupling Structures for Decoupling PIFAs on Handheld Devices

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Qian Li ◽  
Yaxin Yu
Keyword(s):  
Electromagnetic Field ◽  
Correlation Coefficient ◽  
Dielectric Layer ◽  
Mutual Coupling ◽  
Ground Plane ◽  
Measured Data ◽  
Handheld Devices ◽  
Handheld Device ◽  
Small Spacing ◽  
Thin Dielectric Layer

One efficient approach is introduced in this paper to reduce mutual coupling and correlation coefficient for two closely placed PIFAs in a handheld device. The approach is based on one miniaturized structure which consists of two metallic layers, printed on either side of one thin dielectric layer. Due to the small spacing between two conducting patches, high electromagnetic field is induced within the dielectric layer. The geometry and position of this structure have been modified to decouple the PIFA array at 1.9 GHz and produce maximum miniaturization thereby occupying less space on a handheld device ground plane. By employing the proposed structures, a 20 dB reduction in mutual coupling is achieved. The correlation coefficient also reduces to 0.007278. The performance of the structure is validated by both simulated results and measured data obtained from several fabricated prototypes.

scholarly journals Benchmarking Transposable Element Annotation Methods for Creation of a Streamlined, Comprehensive Pipeline

2019 ◽  
Author(s):  
Shujun Ou ◽  
Weija Su ◽  
Yi Liao ◽  
Kapeel Chougule ◽  
Doreen Ware ◽  
...  
Keyword(s):  
Transposable Elements ◽  
Transposable Element ◽  
Open Source ◽  
Performance Metrics ◽  
De Novo ◽  
Relative Performance ◽  
Sequencing Technology ◽  
High Quality ◽  
Link Type ◽  
Assembly Algorithms

AbstractSequencing technology and assembly algorithms have matured to the point that high-quality de novo assembly is possible for large, repetitive genomes. Current assemblies traverse transposable elements (TEs) and allow for annotation of TEs. There are numerous methods for each class of elements with unknown relative performance metrics. We benchmarked existing programs based on a curated library of rice TEs. Using the most robust programs, we created a comprehensive pipeline called Extensive de-novo TE Annotator (EDTA) that produces a condensed TE library for annotations of structurally intact and fragmented elements. EDTA is open-source and freely available: https://github.com/oushujun/EDTA.

Design of Optimum Acoustic Treatment for Rectangular Ducts With Flow

1976 ◽  
Author(s):  
R. E. Motsinger ◽  
R. E. Kraft ◽  
J. W. Zwick
Keyword(s):  
Acoustic Pressure ◽  
Noise Suppression ◽  
Optimization Technique ◽  
Measured Data ◽  
Acoustic Velocity ◽  
Single Element ◽  
Mean Flow ◽  
Acoustic Treatment ◽  
Treatment Design

A design optimization technique for acoustic treatment in rectangular ducts with uniform mean flow is presented. The technique is based on the acoustic wave solution in terms of series of characteristic duct modes. The analysis allows multiple axial treatment sections along the length of the duct and requires a known modal characterization of the sound source. Conditions of acoustic pressure and acoustic velocity continuity are used to match modal solutions at planes of impedance discontinuity in the duct. Experimental techniques for obtaining this modal characterization are presented. Using duct modes measured at the source plane, the optimization technique is exercised to design an optimized single element liner in a case without mean flow, and optimized single and dual element liners in cases with mean flow. The validity of the program for predicting noise suppression is demonstrated by comparing analytical predictions with measured data for several (non-optimum) cases. Application to treatment design in turbomachinery exhaust ducts is considered.

Relative performance of religious and ethical investment funds

2020 ◽  
Vol 11 (6) ◽  
pp. 1227-1244 ◽  
Author(s):  
Esther Castro ◽  
M. Kabir Hassan ◽  
Jose Francisco Rubio ◽  
Zairihan Abdul Halim
Keyword(s):  
Mutual Funds ◽  
Performance Metrics ◽  
Relative Performance ◽  
Data Envelopment ◽  
Ethical Investment ◽  
Socially Responsible ◽  
Investment Funds ◽  
Content Type ◽  
Asset Pricing Models ◽  
The Cost

Purpose This paper updates the literature regarding the performance of constrained US mutual funds by looking at the relative performance of Christian mutual funds, socially responsible funds and Islamic funds. This paper aims to rank the performance of religious and ethical investment funds. Design/methodology/approach This study uses monthly returns from 2005 to 2015 to perform traditional asset pricing models as well as data envelopment analysis to determine rank. Findings Islamic mutual funds outperform socially responsible funds, which then outperform Christian-based mutual funds; these results are also consistent during the latest 2007-2008 crisis period. The results are robust to different performance metrics and benchmarks. Moreover, this paper reports a significant amount of money “left on the table” by investing in constraint funds and disregarding the sin industry which shows an ethical dilemma for investors. Practical implications Investors who seek to invest morally/ethically can be informed of the cost of doing so. They can also compare portfolio with others that have similar holdings and constraints. Originality/value This paper not only includes Christian mutual funds in the research but also provides the performance of all constrained assets. It also compares religious funds with “SIN” industry, and thus quantifies the cost of “doing right.”

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