scholarly journals Basic bounds on cluster error using distortion-rate

2021 ◽  
pp. 100160
Author(s):  
J.R. Bhatnagar
Keyword(s):  
Distortion Rate

A Novel Header Bits Estimation Scheme for H.264/AVC Standard

2013 ◽  
Vol 333-335 ◽  
pp. 787-790
Author(s):  
Shu Qian He ◽  
Zheng Jie Deng ◽  
Chun Shi
Keyword(s):  
Rate Control ◽  
Rate Distortion ◽  
Accurate Estimation ◽  
Rate Estimation ◽  
Proposed Model ◽  
Estimation Function ◽  
Estimation Scheme ◽  
Block Based ◽  
Coding Bits ◽  
Distortion Rate

Rate estimation is useful for many H.264/AVC applications including rate-distortion optimization (RDO) for fast mode decision and precise rate control. In this paper, we propose a new header rate prediction model and an adaptive algorithm to provide more accurate estimation of the number of total coding bits for rate control compared to previously proposed methods. The header bit rate estimation is modeled by a linear combination of the number of mode block, and the sum of absolute values of all motion vectors for each block. Based on the proposed model, a header rate estimation function is also proposed to give a more accurate rate-distortion rate control. The proposed schemes can achieve better results in rate-distortion and rate control to previously proposed approaches.

Mapping of a multilayer panoramic radiography device

2021 ◽  
Author(s):  
Luciano Augusto Cano Martins ◽  
Eduarda Helena Leandro Nascimento ◽  
Hugo Gaêta-Araujo ◽  
Matheus L Oliveira ◽  
Deborah Queiroz Freitas
Keyword(s):  
Exposure Time ◽  
Panoramic Radiography ◽  
Anterior Region ◽  
Panoramic Image ◽  
Panoramic Radiographs ◽  
Acrylic Plate ◽  
Panoramic Images ◽  
Maxilla And Mandible ◽  
Distortion Rate

Objective: To map the shape, location, and thickness of the focal trough of a panoramic radiography device with a multilayer imaging program. Methods: An acrylic plate (148 × 148 × 3 mm) containing 1156 holes distributed in a matrix of 34 × 34 rows was placed in the OP300 Maxio at the levels of the maxilla and mandible. 20 metal spheres (3.5 mm in diameter) were placed on the holes of the plate under 15 different arrangements and panoramic images were acquired for each arrangement at 66 kV, 8 mA, and an exposure time of 16 s. The resulting panoramic radiographs from the five image layers were exported, the horizontal and vertical dimensions of the metal spheres were measured in all images using the Image J software, and the magnification and distortion rates of the spheres were calculated. All metal spheres presenting a magnification rate lower than 30% in both vertical and horizontal dimensions and a distortion rate lower than 10% were considered to map the focal troughs of each of the five image layers. Results: All panoramic image layers had a curved shape ranging from 39° to 51° for both dental arches and varied in position and thickness. The anterior region of maxilla was anteriorly displaced when compared to the anterior region of the mandible for all layers. Image layers are thicker at the level of the mandible than those at the level of the maxilla; also, inner layers were thinner and outer layers were thicker. Conclusion All image layers in the studied panoramic radiography device had a curved shape and varied in position and thickness. The anterior region of maxilla was anteriorly displaced when compared to that of the mandible for all layers.

Series Reactance Rate Design of Shunt Capacitor with the Current-Limiting Reactor in Consideration Based on Particle Swarm Algorithm

2013 ◽  
Vol 291-294 ◽  
pp. 2228-2233
Author(s):  
Cai Jie Fan ◽  
Qiong Lin Li ◽  
Shu Ming Liu ◽  
Yong Hai Xu ◽  
Shuo Wang
Keyword(s):  
Significant Influence ◽  
Optimal Allocation ◽  
Particle Swarm Algorithm ◽  
Actual Situation ◽  
Impedance Model ◽  
Transformer Substation ◽  
Current Limiting ◽  
Rate Design ◽  
Shunt Capacitor ◽  
Distortion Rate

Combined with the actual situation of transformer substation, PSO model is built to optimize the shunt capacitor series reactance rate in this paper. First, system harmonic impedance is analyzed and the harmonic impedance model is built. Second, the objective function and constraints of the optimization algorithm were set. The goal is to make the current distortion rate of high side smallest under the condition of the capacitor banks working safely, the output results will be the optimal allocation of the series reactance rate. Current-limiting reactor was also considered the influence to the design of series reactance rate. At last, testify the effectiveness with comparing the effect to the traditional way of designing the series reactance rate and prove the significant influence of the current-limiting reactor.

scholarly journals Correlation between spatial resolution and ball distortion rate of panoramic radiography

2020 ◽  
Author(s):  
Han-Gyeol Yeom ◽  
Sam-Sun Lee ◽  
Jo-Eun Kim ◽  
Kyung-Hoe Huh ◽  
Won-Jin Yi ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Spatial Resolution ◽  
Panoramic Radiography ◽  
Reference Value ◽  
Vertical Line ◽  
Line Pair ◽  
Horizontal Line ◽  
Student’S T ◽  
High Degree ◽  
Distortion Rate

Abstract BackgroundThe purpose of this study was to analyze the correlation between spatial resolution and ball distortion rate of panoramic radiography and to elucidate the minimum criterion for ball distortion rate, which is very relevant to clinical readability.MethodsHorizontal and vertical spatial resolution and ball distortion rates were calculated in the same position, such as the incisor, premolar, molar, and temporomandibular joint area with various object depths corresponding to 48 mm. Three devices were evaluated. A region showing spatial resolution above the reference standard was selected, and the ball distortion rate corresponding to the same region was divided into horizontal and vertical phantom groups.The mean and standard deviation of the obtained ball distortion rates were calculated. Student’s t-test was used to statistically analyze the mean difference in ball distortion rates between vertical and horizontal phantom groups.ResultsIn all devices, the horizontal line pair phantom, but not the vertical line pair phantom, was readable in all areas measured at the line pair value of at least 1.88 lp/mm. The line pair value tended to be higher toward the center and lower toward the outside. The ball distortion rate tended to decrease closer to the center and increased further away. In addition, ball distortion rates could not be measured at some areas as they were not recognized as balls due to the high degree of distortion at the outermost and innermost sides. The number of balls satisfying the reference value using the horizontal line pair phantom was 102 (mean of ball distortion rates, 20.98; standard deviation, 15.25). The number of balls satisfying the reference value using the vertical line pair phantom was 49 (mean of ball distortion rates, 16.33; standard deviation, 14.25). However, mean ball distortion rate was not significantly different between the two groups.ConclusionsFocal layer of panoramic radiography could be evaluated by the spatial resolution using horizontal and vertical line pair phantoms and by assessing ball distortion rates through a ball-type panorama phantom. A ball distortion rate of 20% could be used as a threshold to evaluate the focal layer of panoramic radiography.

scholarly journals Impactos do Programa de Aquisição de Alimentos (PAA) no Rendimento Escolar dos Municípios do Paraná

2019 ◽  
Vol 20 (4) ◽  
pp. 446-451
Author(s):  
Renata Cattelan ◽  
Lirane Elize Defante Ferreto
Keyword(s):  
School Performance ◽  
Dropout Rate ◽  
Food Shortage ◽  
Early Years ◽  
Pass Rate ◽  
Food Quantity ◽  
Politica Publica ◽  
Keywords Education ◽  
The Impact ◽  
Distortion Rate

No Brasil, ao longo das últimas décadas, algumas políticas públicas procuraram sanar os problemas da carência alimentar. Contudo, a insegurança alimentar tem fatores multidimensionais e impacta de maneiras variadas na vida da população, especialmente de crianças e adolescentes. O impacto da quantidade e qualidade insuficiente dos alimentos pode ser um fator de redução do rendimento escolar. O Programa de Aquisição de Alimentos (PAA) é uma política pública que visa a distribuição de alimentos de qualidade nas escolas, bem como em outros órgãos, e que objetiva gerar renda no campo ao mesmo tempo em que oferece qualidade nutricional. Partindo do problema da carência alimentar para crianças e adolescentes e como isso afeta a produtividade escolar, o objetivo desta pesquisa é avaliar o impacto do PAA no rendimento escolar de crianças e adolescentes que estudam em escolas que são beneficiárias do programa. A metodologia utilizada foi o teste de Mann-Whitney e as variáveis utilizadas foram o IDEB, a taxa de aprovação, a taxa de abandono escolar e a taxa de distorção idade/série para o ensino fundamental séries iniciais e finais. O recorte geográfico é o estado do Paraná, e temporal, os anos de 2013 e 2015. O principal resultado do estudo mostrou que a variável taxa de distorção idade/série dos anos iniciais do ensino fundamental, para o grupo formado pelos municípios afetados pelo PAA, obteve melhora estatisticamente significativa em relação a municípios que não participaram do programa. Palavras-chave: Educação. Segurança Alimentar e Nutricional. Teste de Mann-Whitney. AbstractIn Brazil, over the last decades, some public policies have tried to remedy the problems of food shortage. However, food insecurity has multidimensional factors and impacts in various ways on the lives of the population, especially children and teenagers. The impact of insufficient food quantity and quality may be a factor in reducing school performance. The Food Acquisition Program (FAP) is a public policy aimed at the distribution of quality food in schools as well as other agencies, and which aims to generate income in the countryside while providing nutritional quality. Starting from the problem of food shortage for children and teenagers, and how it affects school productivity, the objective of this research is to evaluate the impact of FAP on the school performance of children and adolescents who study in schools that benefit from the program. The methodology used was the Mann-Whitney test and the variables used were the IDEB, the pass rate, the dropout rate and the age / grade distortion rate for elementary and early grades. The geographical cut is the state of Paraná, and temporal, the years 2013 and 2015. The main result of the study showed that the variable age / grade distortion rate of the early years of elementary school, for the group formed by the municipalities affected by the FAP, obtained statistically significant improvement compared to counties that did not participate in the program. Keywords: Education. Food Safety and Nutrition. Test of Mann-Whitney. 

scholarly journals Research on Output Waveform of Generator with Rectifier Load considering Commutation Overlap Angle

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Bingyi Zhang ◽  
Gongfei He ◽  
Guihong Feng
Keyword(s):  
Circuit Simulation ◽  
Harmonic Distortion ◽  
Simulation Method ◽  
Conduction Time ◽  
Current Waveform ◽  
Voltage Waveform ◽  
Rectifier Circuit ◽  
Output Waveform ◽  
Output Side ◽  
Distortion Rate

The purpose of this paper is to study the influence of the uncontrolled rectifier circuit on the generator’s output waveform when considering the commutation overlap angle. Taking the nonsalient permanent magnet (PM) generator directly connected with the uncontrolled rectifier circuit as an example, the equivalent circuit of the generator with rectifier load is established, and the commutation process of the rectifier circuit is analyzed when the effect of the commutation overlap angle is considered. The output waveforms of generator’s output side are obtained by analytical method, circuit simulation method, field-circuit coupled simulation method, and experimental method. The validity of the analysis methods is demonstrated by comparison. According to the results of analytical analysis, we know the characteristics of the output waveform under the influence of the commutation overlap angle. The existence of the commutation overlap angle will cause the voltage waveform to concave or convex, prolong the conduction time of the winding, and result in phase difference between the voltage waveform and current waveform. The influence of synchronous inductance and extra inductance on the output waveforms and harmonic distortion rate is analyzed. The research of this paper provides a theoretical basis for improving the output waveform of the generator with rectifier load.

scholarly journals An Enhanced Multimedia Video Surveillance Security Using Wavelet Encryption Framework

2020 ◽  
Author(s):  
Velliangiri S
Keyword(s):  
Wavelet Transform ◽  
False Positive Rate ◽  
Digital Data ◽  
Detection Accuracy ◽  
Detection Time ◽  
Arbitrary Permutation ◽  
Secret Keys ◽  
Positive Rate ◽  
Cae System ◽  
Distortion Rate

Multimedia digital data include medical record and financial documents, which are not guaranteed with security. The concerns for security of multimedia digital data is been a widespread issue in the field of cybernetics. With increasing malwares in video payloads, the proposed study aims to reduce the embedding of malwares using Pseudo Arbitrary Permutation based Cellular Automata Encryption (PAP-CAE) System in video payloads. This method reduces the malware attacks and distortion rate by permuting the secret keys with Pseudo arbitrary permutation. Before the application of PAP-CAE, 2D wavelet transform is applied on the multimedia files that compresses the complex files into different scales and position to be transmitted via a network with reduced size. Simultaneously, it performs the process of decryption and decompression to retrieve the original files. The proposed method is evaluated against existing methods to test its efficacy in terms of detection accuracy, detection time of malwares and false positive rate. The result shows that the proposed method is effective against the detection of malwares in multimedia video files.

Sign in / Sign up

Export Citation Format

Share Document