11 |
A Study of the Effect of Non-Ideal Factors on Normalized Site Attenuation in Open Area Test SiteWang, Wei-Te 07 July 2003 (has links)
The CISPR of IEC in European and the ANSI in American use the model of site attenuation to evaluate and quantify the quality of OATS. The ANSI also uses the concept of Normalized Site Attenuation (NSA) to eliminate the effects brought about by different antennas, which may cause the inaccuracy of site attenuation. To stringently require the quality of OATS, the measured values of NSA have to be compared with the theoretical ones. If their differences are within (+/-)4 dB at all frequencies, the test environment of the OATS can be accepted.
At present, the theoretical values of NSA are used as a standard for verifying the OATS in the world. However, many non-ideal factors derived from certain assumptions and simplifications of the NSA may cause the measured NSA to deviate from the theoretical values. To understand the manner and extent of the effects, in this thesis we find out the non-ideal factors by studying the NSA by numerically simulating the effects of each factor on NSA measurement by the method of moment (MoM), and the results are analyzed and discussed. We find that there is a difference of 6 dB on the NSA when the impedance of the receive antenna is mismatched. Meanwhile, we also study the relationship between the conductivity of non-perfect electrical conductor and the ideal value of NSA. We conclude that a ground plane made by metal can be regarded as a PEC one. However, the values of NSA will increase if the conductivity of ground plane is below 1000 S/m. Besides, considering the humid Taiwan climate in particular, we investigate the condition of a thin layer of water covering the ground plane after rain and the results show that the effect of the water plane will decrease the values of NSA. As for the measurement at a distance of 3 m, a deviation of 2 dB at low frequencies arises from the effect of near field for the case of horizontal polarization. Finally as for the non-conducting table in OATS, our results show that the larger values of relative permittivity and conductivity of table result in the larger change of NSA value. The difference can be 3 dB for the case with a wooden table.
With results of our research, the effects of non-ideal factors on NSA measurement can be comprehended clearly. The comparison of the differences also can be used as a reference for the modification of the NSA measurement in the future.
|
12 |
Application of Hybrid Antennas in Normalized Site Attenuation Measurements and An Improved Method for Free-space Antenna Factor MeasurementChen, Hsing-Feng 18 January 2010 (has links)
This thesis first discusses the ground plane effects of a test site on the antenna factors (AFs) of hybrid antenna (biconical log-periodic dipole array). Meanwhile, the effects of mutual coupling between antenna and its image, and the variation of active phase center are also discussed. From these analyses, a hybrid method, based on the modified SSM (Standard Site Method) and the PCPM (Phase Center and Pattern Matching) applied to the hybrid antenna for NSA (Normalized Site Attenuation) measurement is proposed. By this method, the low geometry- dependent AFs of hybrid antenna can be obtained to produce more reasonable NSA values for a test site.
Secondly, this thesis proposes a simple, fast, and accurate method to calibrate the free-space AFs of broadband EMC (Electromagnetic Compatibility) antennas. This method adopts a fixed-height configuration and a MUSIC (MUltiple SIgnal Classification) algorithm. This configuration significantly shortens measurement time and removes height-dependent calibration errors. Meanwhile, the MUSIC algorithm can remove unexpected reflections from the ground plane or any other reflecting objects, by which the free-space AFs can be calculated. In addition, this method can also automatically compensate for the phase center shift, which makes measurement easier and more convenient. To verify this method, the calibrated results are compared with other published standard methods: the mean differences can be as low as 0.25 dB for the LPDA (log-periodic dipole array), 0.42 dB for the hybrid antennas, and 0.36 dB for the horn antennas.
Finally, this thesis provides a method of using two equivalent negative inductances from two terminals of three coupled inductors to reduce the parasitic inductances of a typical three-capacitor EMI (Electromagnetic Interference) filter. Theoretical analysis and formula deduction for the design of two equivalent negative inductances are demonstrated. The experimental results show that the insertion losses of a three-capacitor EMI filter at 50 MHz can be reduced by 16.8 dB for the DM (differential-mode) and by 19.2 dB for the CM (common-mode).
In Appendix A of this thesis, an extended study of the effect of ground plane on antenna¡¦s radiation is described. A simple V-shape edge-groove design for a finite ground plane can effectively reduce the pattern ripples of a monopole. The optimal design of proposed structure can reduce the peak-to-peak pattern ripples from 26 to 4.5 dB.
|
13 |
EVALUATING NORMALIZED SAMPLES OF PEAK TRAININGWoods, Aleta Marcel 01 August 2014 (has links)
The PEAK Relational Training Program has been recently published and favorable results for reliability and validity measures have been reported (Dixon, 2014). Results of two studies have demonstrated a high correlation with scores on the PEAK assessment scores, IQ scores as well as high reliability in scoring the PEAK assessments (Dixon, Carman, Tyler, Whiting, Enoch, & Daar, In press; Dixon, Whiting, Rowsey, & Belisle, In press). The current study evaluated normative data for Module 1 using 45 children ages 1 through 6 to validate it's utility in measuring the language of typically developing individuals. Normative data was collected and a strong positive correlation was identified between participants' age and PEAK assessment scores (r=.832, p=<.001). Implications support the use of PEAK to teach language and learning and continual investigation of its psychometric properties.
|
14 |
Normalized Forces and Active Range of Motion in Unilateral Radial Epicondylalgia (Tennis Elbow)Benjamin, Scott J., Williams, Duane A., Kalbfleisch, John H., Gorman, Paul W., Panus, Peter C. 01 January 1999 (has links)
Study Design: Single group pretest-posttest. Background: There is a lack of consensus concerning the preferred assessment and treatment for radial epicondylalgia. Objectives: Determine whether deficiencies in muscle force, joint range of motion, or painful force threshold are detected when measurements from the involved upper extremity are normalized to values from the uninvolved extremity. Methods and Measures: Ten patients (70% men) 42 ± 7 years in age with unilateral radial epicondylalgia participated. The visual analog pain scale and 6 measurements involving either muscle force, joint range of motion, or painful force threshold were examined. Results: When comparing the initial assessments to final assessments, a significant improvement was found for the visual analog pain scale (5 ± 3 vs 1 ± 3) and for the following normalized scores: grip (78 ± 26% vs 101 ± 20%) and isometric wrist extension forces (68 ± 24% vs 95 ± 35%), painful force threshold over the lateral epicondyle (49 ± 22% vs 94 ± 14%), and active wrist extension range of motion (83 ± 13% vs 96 ± 10%). Conclusions: Normalized force and range of motion measurements following treatment for unilateral radial epicondylalgia are sensitive assessments of patient progress. In comparison with measurements of force and range of motion that are not adjusted to a baseline score, normalized measurements detect changes in patient responses when baseline scores vary.
|
15 |
A Head-mounted Accelerometer System for Motion Classification of Personnel in Hazardous Work AreasMujumdar, Madhura 19 October 2015 (has links)
No description available.
|
16 |
Use of Landsat Data to Characterize Burn Severity, Forest Structure and Invasion by Paulownia (Paulownia Tomentosa) in an Eastern Deciduous Forest, KentuckyUpadhaya, Suraj 01 January 2015 (has links)
Landsat imagery has been used successfully to assess burn severity and monitor post-fire forest structure in a variety of ecosystems, but to date there are few documented studies on its application in the eastern deciduous forests of the eastern United States. The occurrence of a wildfire in the Daniel Boone National Forest in2010 provided a rare opportunity for research into the use of Landsat data for assessing burn severity and its ecological effects. We used differenced normalized burn ratio (∆NBR) to quantify burn severity. The ∆NBR based burn severity classification had 70% agreement with a qualitative ground-based burn severity assessment. We also examined the relationship between the presence of an invasive species (Paulownia tomentosa), and our assessment of burn severity, where we found a weak but statistically significant relationship (adj R2 0.13, p<0.0001). We also examined the relationship between the normalized difference vegetation index (NDVI) and forest structure measurements. The relationship between NDVI and basal area was strongly and significantly related (adj R2 0.41, p<0.0001). The relationship of NDVI with stem density was weak but significant (adj R2 0.23. p=0.004). These results indicate that data from Landsat imagery have great potential for quantifying burn severity, identifying potential hotspots for invasive species, and assessing post fire forest structure in the eastern deciduous forest.
|
17 |
A relação entre a temperatura radiométrica de superfície (Land Surface Temperature-LST), índice de vegetação (Normalizes Diference Vegetation Index-NDVI) e os diferentes padrões de uso da terra do município de São Paulo / The relationship between surface radiometric temperature (Land Surface Temperature-LST), vegetation index (Normalized Vegetation Index diference-NDVI) and the different land use patterns in São Paulo-SP.Jesus, Bruna Luiza Pereira de 15 September 2015 (has links)
Esse trabalho tem como objetivo compreender as relações entre a Land Surface Temperature (LST), Normalized Difference Vegetation Índex (NDVI) e os padrões do uso da terra do município de São Paulo no período de 1985 a 2010. Analisou-se 15 bairros, nos quais foram extraídas 45 amostras aleatórias de diferentes padrões de uso da terra; subdivididas em baixo padrão, médio padrão e médio alto padrão. Com o aporte de geotecnologia, foi feita a extração dos dados das imagens de satélite Landsat 5 (TM) e das Ortofotos do ano de 2010. O comportamento das amostras variou de acordo como os diferentes perfis dos grupos analisados. O grupo de baixo padrão foi o que apresentou as maiores amplitudes térmicas, ausência de arborização urbana atreladas a um baixo padrão construtivo. O grupo de médio padrão é caracterizado pela predominância de área verticalizada e apresenta uma arborização urbana escassa em meio a uma malha urbana consolidada. O grupo de médio alto padrão foi o que mais apresentou arborização urbana, distribuída de forma homogênea na maioria das amostras, portanto foi o grupo que teve baixas amplitudes térmicas e o índice de Normalized Difference Vegetation Index (NDVI) com pouca variação. Os testes mostraram fortes correlações negativas entre as amostras de Land Surface Temperature (LST) e o índice de Normalized Difference Vegetation Index (NDVI), sendo -0,58 em 1985, -0,43 em 2004 e -0,82 em 2010. Os diferentes padrões de uso da terra, relacionados à temperatura de superfície, e o índice de vegetação, aliado à preocupação com o planejamento ambiental, deve resultar na melhoria da qualidade de vida da população. Esta pesquisa faz parte do Projeto Temático processo FAPESP 08/58161 -1, \"Assessment of Impacts and Vulnerability to Climate Change in Brazil and strategies for Adaptation options\", Component 5: Vulnerability of the metropolitan region of São Paulo to climate Change. / This study aims to understand the relationship between Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI) and the patterns of land use in the municipality of São Paulo, from 1985 to 2010. A totoal of 45 random samples were extracted from the 15 districts used in this study, with different patterns of land use which were subdivided into three different clases: low-end, middle and middle-high. Geospatial approaches allowed the extraction of satellite image data from Landsat 5 data (TM) and from Orthophotos from 2010. The behavior of the samples varied accordingly to the different group profiles. The low-end group presented the highest thermal amplitudes and more significant absence of urban vegetation linked, both to low urbanization and construction standards. The average standard group is characterized by the predominance of vertical buildings and lacks urban trees amidst a consolidated urban landscape. The average-high standard group displayed the highest concentration of green urban areas, distributed homogeneously in most samples, so this group presented low variations both in temperature amplitude and in the Normalized Difference Vegetation Index (NDVI). The correlation tests showed strong negative correlations between samples of Land Surface Temperature (LST) and the NDVI samples, of -0.58 in 1985, -0.43 in 2004 and -0.82 in 2010. Understanding the relations between the different patterns of land use, surface temperature and the NDVI (with due concern for environmental planning) is an important step in the identification and rehabilitation of enviromentally. This research is part of the Thematic Project FAPESP 08/58161 -1 process, \"Assessment of Impacts and Vulnerability to Climate Change in Brazil and strategies for Adaptation options\", Component 5: Vulnerability of the metropolitan region of São Paulo to climate Change.
|
18 |
A relação entre a temperatura radiométrica de superfície (Land Surface Temperature-LST), índice de vegetação (Normalizes Diference Vegetation Index-NDVI) e os diferentes padrões de uso da terra do município de São Paulo / The relationship between surface radiometric temperature (Land Surface Temperature-LST), vegetation index (Normalized Vegetation Index diference-NDVI) and the different land use patterns in São Paulo-SP.Bruna Luiza Pereira de Jesus 15 September 2015 (has links)
Esse trabalho tem como objetivo compreender as relações entre a Land Surface Temperature (LST), Normalized Difference Vegetation Índex (NDVI) e os padrões do uso da terra do município de São Paulo no período de 1985 a 2010. Analisou-se 15 bairros, nos quais foram extraídas 45 amostras aleatórias de diferentes padrões de uso da terra; subdivididas em baixo padrão, médio padrão e médio alto padrão. Com o aporte de geotecnologia, foi feita a extração dos dados das imagens de satélite Landsat 5 (TM) e das Ortofotos do ano de 2010. O comportamento das amostras variou de acordo como os diferentes perfis dos grupos analisados. O grupo de baixo padrão foi o que apresentou as maiores amplitudes térmicas, ausência de arborização urbana atreladas a um baixo padrão construtivo. O grupo de médio padrão é caracterizado pela predominância de área verticalizada e apresenta uma arborização urbana escassa em meio a uma malha urbana consolidada. O grupo de médio alto padrão foi o que mais apresentou arborização urbana, distribuída de forma homogênea na maioria das amostras, portanto foi o grupo que teve baixas amplitudes térmicas e o índice de Normalized Difference Vegetation Index (NDVI) com pouca variação. Os testes mostraram fortes correlações negativas entre as amostras de Land Surface Temperature (LST) e o índice de Normalized Difference Vegetation Index (NDVI), sendo -0,58 em 1985, -0,43 em 2004 e -0,82 em 2010. Os diferentes padrões de uso da terra, relacionados à temperatura de superfície, e o índice de vegetação, aliado à preocupação com o planejamento ambiental, deve resultar na melhoria da qualidade de vida da população. Esta pesquisa faz parte do Projeto Temático processo FAPESP 08/58161 -1, \"Assessment of Impacts and Vulnerability to Climate Change in Brazil and strategies for Adaptation options\", Component 5: Vulnerability of the metropolitan region of São Paulo to climate Change. / This study aims to understand the relationship between Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI) and the patterns of land use in the municipality of São Paulo, from 1985 to 2010. A totoal of 45 random samples were extracted from the 15 districts used in this study, with different patterns of land use which were subdivided into three different clases: low-end, middle and middle-high. Geospatial approaches allowed the extraction of satellite image data from Landsat 5 data (TM) and from Orthophotos from 2010. The behavior of the samples varied accordingly to the different group profiles. The low-end group presented the highest thermal amplitudes and more significant absence of urban vegetation linked, both to low urbanization and construction standards. The average standard group is characterized by the predominance of vertical buildings and lacks urban trees amidst a consolidated urban landscape. The average-high standard group displayed the highest concentration of green urban areas, distributed homogeneously in most samples, so this group presented low variations both in temperature amplitude and in the Normalized Difference Vegetation Index (NDVI). The correlation tests showed strong negative correlations between samples of Land Surface Temperature (LST) and the NDVI samples, of -0.58 in 1985, -0.43 in 2004 and -0.82 in 2010. Understanding the relations between the different patterns of land use, surface temperature and the NDVI (with due concern for environmental planning) is an important step in the identification and rehabilitation of enviromentally. This research is part of the Thematic Project FAPESP 08/58161 -1 process, \"Assessment of Impacts and Vulnerability to Climate Change in Brazil and strategies for Adaptation options\", Component 5: Vulnerability of the metropolitan region of São Paulo to climate Change.
|
19 |
Bangladesh Shoreline Changes During the Last Four Decades Using Satellite Remote Sensing DataGuo, Qi January 2017 (has links)
No description available.
|
20 |
DESIGN AND DEVELOPMENT OF AN AUTONOMOUS SOCCER-PLAYING ROBOTOlson, Steven A. R., Dawson, Chad S., Jacobson, Jared 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / This paper describes the construction of an autonomous soccer playing robot as part of a senior design project at Brigham Young University. Each participating team designed and built a robot to compete in an annual tournament. To accomplish this, each team had access to images received from a camera placed above a soccer field. The creation of image processing and artificial intelligence software were required to allow the robot to perform against other robots in a one-on-one competition. Each participating team was given resources to accomplish this project. This paper contains a summary of the experiences gained by team members and also a description of the key components created for the robot named Prometheus to compete and win the annual tournament.
|
Page generated in 0.0349 seconds