scholarly journals Diversity Performance of Multiantenna Systems for UMTS Cellular Phones in Different Propagation Environments

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
A. Diallo ◽  
C. Luxey ◽  
P. Le Thuc ◽  
R. Staraj ◽  
G. Kossiavas
Keyword(s):  
Correlation Coefficient ◽  
Antenna System ◽  
Diversity Gain ◽  
Total Efficiency ◽  
Cellular Phones ◽  
Radiation Patterns ◽  
Reverberation Chamber ◽  
The Mean ◽  
Antenna Systems ◽  
Diversity Antenna

We present the evaluation of the diversity performance of several two-antenna systems for UMTS terminals. First, a two-antenna system with poor antenna-to-antenna isolation is described. Then, with the help of a neutralization technique, we introduced an optimized structure with high antenna-to-antenna isolation. The key parameters for an efficient diversity performance are then discussed, some of them being actually dependent on the propagation environment (uniform, indoor, outdoor, and outdoor-to-indoor chosen here). All these parameters, the total efficiency, the envelope correlation coefficient, the mean effective gain, the diversity gain, and the effective diversity gain, are computed with the help of the simulated radiation patterns of both antenna systems. Next, these key parameters are measured in a reverberation chamber to validate the simulations we achieved in the uniform environment. The comparison of the performance of the two prototypes is especially showing the usefulness of using a neutralization technique for enhanced diversity antenna systems.

scholarly journals A Compact UWB Diversity Antenna

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Hui Zhao ◽  
Fushun Zhang ◽  
Chunyang Wang ◽  
Jiangang Liang
Keyword(s):  
Correlation Coefficient ◽  
Ground Plane ◽  
Impedance Bandwidth ◽  
Antenna Gain ◽  
Radiation Patterns ◽  
Frequency Range ◽  
Microstrip Lines ◽  
Uwb Applications ◽  
Diversity Antenna ◽  
Envelope Correlation

A compact printed ultrawideband (UWB) diversity antenna with a size of 30 mm × 36 mm operating at a frequency range of 3.1–10.6 GHz is proposed. The antenna is composed of two semielliptical monopoles fed by two microstrip lines. Two semicircular slots, two rectangular slots, and one stub are introduced in the ground plane to adjust the impedance bandwidth of the antenna and improve the isolation between two feeding ports. The simulated and measured results show that impedance bandwidth of the proposed antenna can cover the whole UWB band with a good isolation of < −15 dB. The radiation patterns, peak antenna gain, and envelope correlation coefficient are also measured and discussed. The measured results show that the proposed antenna can be a good candidate for some portable MIMO/diversity UWB applications.

scholarly journals A Study of Antenna System for High Order MIMO Device

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Zhaoliang Chen ◽  
Wen Geyi ◽  
Ming Zhang ◽  
Jun Wang
Keyword(s):  
Multiple Input Multiple Output ◽  
Correlation Coefficients ◽  
Antenna System ◽  
Antenna Element ◽  
Mimo Antenna ◽  
Pattern Diversity ◽  
Multiple Input ◽  
Input Multiple Output ◽  
The Mean ◽  
Antenna Systems

Three types of compact MIMO (Multiple-Input Multiple-Output) antenna systems with four and six elements for mobile handsets are studied in this paper. The MIMO antenna system is built on a FR4 substrate of the dimensions 136 mm × 68.8 mm × 1 mm. The antenna element is a folded planar inverted-F antenna with added resonating branches wound on a small dielectric cube of the dimensions 10 mm × 10 mm × 5 mm, which is the smallest volume so far reported covering the frequency bands 1880 MHz–1920 MHz and 2300 MHz–2620 MHz for GSM1900, LTE2300, 2.4-GHz WLAN, and LTE2500. The effects of element numbers and configurations on the system performance are investigated. More than 10 dB isolations have been achieved by properly designing the antenna elements through the use of the pattern diversity without using decoupling circuits. The envelope correlation coefficients among the elements, the mean effective gains, the efficiencies, and the multiplexing efficiencies of the elements are also discussed.

THE EFFECT OF ALTERATION OF THYROXINE BINDING CAPACITY ON THE DIALYZABLE AND ABSOLUTE FRACTIONS OF TRIIODOTHYRONINE IN CIRCULATION

1973 ◽  
Vol 72 (2) ◽  
pp. 265-271 ◽  
Author(s):  
J. H. Dussault ◽  
D. A. Fisher ◽  
J. T. Nicoloff ◽  
V. V. Row ◽  
R. Volpe
Keyword(s):  
Correlation Coefficient ◽  
Inverse Relationship ◽  
Binding Capacity ◽  
Hormone Concentration ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
A Value ◽  
The Mean ◽  
Male Subjects ◽  
Female Subjects

ABSTRACT In order to determine the effect of alterations in binding capacity of thyroxine binding globulin (TBG) on triiodothyronine (T3) metabolism, studies were conducted in 10 patients with idiopathically low (7 subjects) or elevated (3 subjects) TBG levels and 10 subjects given norethandrolone (7 male subjects) or oestrogen (3 female subjects). Measurements of serum thyroxine (T4) concentration, maximal T4 binding capacity, serum T3 concentration and per cent dialyzable T3 were conducted. Serum T3 was measured both by chemical and radioimmunoassay methods. In patients with idiopathically low TBG, the mean serum T4 concentration was low (2.4 μg/100 ml), the mean serum T3 level low (55 ng/100 ml), the mean per cent dialyzable T3 increased (0.52%), and the calculated free T3 concentration normal (186 pg/100 ml). In patients with idiopathically high TBG levels the mean T4 concentration was high (10.3 μg/100 ml), the mean T3 level slightly elevated (127 ng/100 ml), the% dialyzable T3 low (0.10%) and the calculated free T3 concentration low normal (123 pg/100 ml). The correlation coefficient between the per cent dialyzable T3 and maximal TBG binding capacity in the 20 subjects was 0.68, a value significant at the P < 0.01 level. Thus, alterations in binding capacity of TBG seem to influence T3 and T4 metabolism similarly; the inverse relationship between the % of dialyzable hormone and total hormone concentration tends to keep the absolue levels of free hormones stable.

scholarly journals Effect of Posterior Tibial Slope Change on Postoperative Range of Motion and Clinical Outcomes after Posterior Cruciate-Substituting Total Knee Arthroplasty

2021 ◽  
Author(s):  
O-Sung Lee ◽  
Jangyun Lee ◽  
Myung Chul Lee ◽  
Hyuk-Soo Han
Keyword(s):  
Total Knee Arthroplasty ◽  
Range Of Motion ◽  
Correlation Coefficient ◽  
Knee Arthroplasty ◽  
Tibial Slope ◽  
Posterior Tibial Slope ◽  
Posterior Tibial ◽  
Clinical Scores ◽  
Total Knee ◽  
The Mean

AbstractThe posterior tibial slope (PTS) is usually adjusted by less than 5 degrees, without considering its individual difference, during posterior cruciate-substituting (PS) total knee arthroplasty (TKA). The effect of these individual changes of PTS would be important because clinical results depending on postoperative PTS were reported conflictingly. We investigated the effect of the change in PTS on the postoperative range of motion (ROM) and clinical scores after PS TKA. We retrospectively reviewed 164 knees from 107 patients who underwent PS TKA with a 2-year follow-up. We analyzed the preoperative and postoperative PTS, ROM, visual analog scale pain scale, Western Ontario and McMaster University Index (WOMAC), Hospital for Special Surgery Knee Score, Knee Society Score, and Forgotten Joint Score (FJS). The association of the absolute change in PTS with ROM and clinical scores was analyzed using correlation analysis and multiple regression analysis. As a result, the mean PTS and mean ROM changed from 9.6 ±  3.4 and 120.1 ±  15.4 degrees preoperatively to 2.0 ±  1.3 and 128.4 ±  9.3 degrees postoperatively, and the mean PTS change was 7.6 ±  3.5 degrees. The PTS change had no statistically significant association with the postoperative ROM and clinical scoring systems, although it did have a weak positive correlation with WOMAC function, No 10 (difficulty in rising from sitting) (correlation coefficient = 0.342, p = 0.041), and moderate positive correlation with the FJS, No. 6 (awareness when climbing stairs) (correlation coefficient = 0.470, p = 0.001). The authors concluded that the amount of change in PTS did not affect the postoperative ROM and clinical scores, although proximal tibial resection with a constant target of PTS resulted in individually different changes in the PTS after PS TKA,

Reverberation Chamber Techniques for Determining the Radiation and Total Efficiency of Antennas

2012 ◽  
Vol 60 (4) ◽  
pp. 1758-1770 ◽  
Author(s):  
Christopher L. Holloway ◽  
Haider A. Shah ◽  
Ryan J. Pirkl ◽  
William F. Young ◽  
David A. Hill ◽  
...  
Keyword(s):  
Total Efficiency ◽  
Reverberation Chamber

Fade Statistic Analysis of SC in Distributed Antenna System

2013 ◽  
Vol 336-338 ◽  
pp. 1708-1712
Author(s):  
Lei Li ◽  
Xiao Dong Wang
Keyword(s):  
Antenna System ◽  
Multiple Antenna ◽  
Level Crossing ◽  
Distributed Antenna System ◽  
Level Crossing Rate ◽  
Composite Fading ◽  
Distributed Antenna ◽  
Diversity Gains ◽  
Antenna Systems ◽  
Average Fade Duration

Exact and closed form expressions for the average level crossing rate (LCR) and average fade duration (AFD) of the output signal envelope of selection diversity system are derived, assuming each branch is subject to independent but nonidentical composite fading in distributed antenna systems (DAS). Numerical results validate the derived expressions. It shows that DAS promise significant diversity gains over collocated multiple antenna system.

Pyridoxine Deficiency After Solid Organ Transplant

2017 ◽  
Vol 27 (3) ◽  
pp. 251-256
Author(s):  
Summer Van Arsdale ◽  
Sarah E. Yost ◽  
Chiu-Hsieh Hsu ◽  
Mary Meer ◽  
Shari Schoentag ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Solid Organ Transplantation ◽  
Organ Transplant ◽  
Multivariate Logistic Regression Analysis ◽  
Study Cohort ◽  
Solid Organ ◽  
Immune Functions ◽  
Pyridoxine Deficiency ◽  
The Mean ◽  
Low Levels

Objective: Pyridoxine is 1 of 8 B vitamins that assist in a variety of essential functions including immune functions. The purpose of this study was to assess the risk factors associated with low pyridoxine levels in solid organ transplantation recipients. Design: The study cohort was divided into 2 groups: (a) patients with normal pyridoxine levels or (b) patients with low pyridoxine levels. Dietary evaluation and clinical characteristics of all patients, rejection episodes, and immunosuppression were collected. Simple descriptive statistics were used to analyze the overall cohort. Results: Of the 48 patients, 29 (60%) in the study cohort were identified to have low pyridoxine levels. The mean interval between transplantation and pyridoxine level check was 910 days (standard deviation [SD] 456). The mean weight at the time of dietary consultation was 80 kg (SD 20.7). More patients in the deficient group received thymoglobulin for rejection treatment (56% vs 0%; P = .01) and were thymoglobulin recipients (78% vs 10%; odds ratio [OR] = 31.5; 95% confidence interval [CI], 2.35-422.30; P < .01). A strong correlation was identified between thymoglobulin treatment for induction and a low level of pyridoxine (correlation coefficient R = 0.6, P = .004) and between thymoglobulin treatment for rejection and a low pyridoxine level (correlation coefficient R = 0.5, P = .05). Based on multivariate logistic regression analysis, only thymoglobulin treatment (induction or rejection treatment) was significantly associated with low pyridoxine levels (OR = 19.5, 95% CI, 1.01-375.24; P < .05). Conclusions: Low levels of pyridoxine appear to be relatively common, and thymoglobulin treatments are associated with low pyridoxine levels. Prospective studies are needed to confirm and valuate the significance of these findings.

scholarly journals Evaluation of Genetic behavior of Sunflower (Helianthus annuus L.) As Effect by Planting Dates

2019 ◽  
Vol 9 (1) ◽  
pp. 150-155
Author(s):  
Abdullah F. Serheed ◽  
Haider T. Hussein
Keyword(s):  
Helianthus Annuus ◽  
Correlation Coefficient ◽  
Environmental Conditions ◽  
Genetic Variance ◽  
Planting Dates ◽  
Environmental Variance ◽  
Growing Seasons ◽  
The Mean ◽  
Phenotypic Variations ◽  
Coefficient Stability

Afield experiment was carried out during the spring and autumn seasons of 2016 and 2017 in AL- Musaib city / 40 km north of Babylon Provence. Two hybrids of sunflower( shamus, French hybrid (Euroflor) were used to evaluate the performance of the two cultivars at both growing seasons as well as knowledge of genetic behavior by studying the genetic and phenotypic variations, heritability percent, genetic and phenotypic coefficient, stability and persistence of the two cultivars .The results showed significant differences of the studied traits, as the genetic genotype (Shamus) most of the characteristics, especially in yield for two seasons.The genetic variance was higher than the environmental variance for the two seasons indicating that the two cultivars followed the same behavior. The heritability percent the dominant sense was high for most of the traits. The genetic and phenotypic variations between the mean and the high were different for the two seasons, the correlation coefficient was significant, for both cultivars, indicating the appropriateness of the two genotypes for the country's environmental conditions.

scholarly journals A Quantitative Comparison of Multispectral Refraction Topography and Autorefractometer in Young Adults

2021 ◽  
Vol 8 ◽  
Author(s):  
Yunru Liao ◽  
Zhenlan Yang ◽  
Zijing Li ◽  
Rui Zeng ◽  
Jing Wang ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Pearson Correlation ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
High Agreement ◽  
Intraclass Correlation Coefficients ◽  
Repeatability And Reproducibility ◽  
The Mean

Purpose: Purpose of this study is to evaluate the measuring consistency of central refraction between multispectral refraction topography (MRT) and autorefractometry.Methods: This was a descriptive cross-sectional study including subjects in Sun Yat-sen Memorial Hospital from September 1, 2020, to December 31, 2020, ages 20 to 35 years with a best corrected visual acuity of 20/20 or better. All patients underwent cycloplegia, and the refractive status was estimated with autorefractometer, experienced optometrist and MRT. We analyzed the central refraction of the autorefractometer and MRT. The repeatability and reproducibility of values measured using both devices were evaluated using intraclass correlation coefficients (ICCs).Results: A total of 145 subjects ages 20 to 35 (290 eyes) were enrolled. The mean central refraction of the autorefractometer was −4.69 ± 2.64 diopters (D) (range −9.50 to +4.75 D), while the mean central refraction of MRT was −4.49 ± 2.61 diopters (D) (range −8.79 to +5.02 D). Pearson correlation analysis revealed a high correlation between the two devices. The intraclass correlation coefficient (ICC) also showed high agreement. The intrarater and interrater ICC values of central refraction were more than 0.90 in both devices and conditions. At the same time, the mean central refraction of experienced optometrist was −4.74 ± 2.66 diopters (D) (range −9.50 to +4.75D). The intra-class correlation coefficient of central refraction measured by MRT and subjective refraction was 0.939.Conclusions: Results revealed that autorefractometry, experienced optometrist and MRT show high agreement in measuring central refraction. MRT could provide a potential objective method to assess peripheral refraction.

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