scholarly journals Singular Measures and Information Capacity of Turbulent Cascades

2020 ◽  
Vol 125 (10) ◽  
Author(s):  
Michal Shavit ◽  
Gregory Falkovich
Author(s):  
D. C. Joy ◽  
R. D. Bunn

The information available from an SEM image is limited both by the inherent signal to noise ratio that characterizes the image and as a result of the transformations that it may undergo as it is passed through the amplifying circuits of the instrument. In applications such as Critical Dimension Metrology it is necessary to be able to quantify these limitations in order to be able to assess the likely precision of any measurement made with the microscope.The information capacity of an SEM signal, defined as the minimum number of bits needed to encode the output signal, depends on the signal to noise ratio of the image - which in turn depends on the probe size and source brightness and acquisition time per pixel - and on the efficiency of the specimen in producing the signal that is being observed. A detailed analysis of the secondary electron case shows that the information capacity C (bits/pixel) of the SEM signal channel could be written as :


2020 ◽  
pp. 15-23
Author(s):  
V. M. Grechishnikov ◽  
E. G. Komarov

The design and operation principle of a multi-sensor Converter of binary mechanical signals into electrical signals based on a partitioned fiber-optic digital-to-analog Converter with a parallel structure is considered. The digital-to-analog Converter is made from a set of simple and technological (three to five digit) fiber-optic digital-to-analog sections. The advantages of the optical scheme of the proposed. Converter in terms of metrological and energy characteristics in comparison with single multi-bit converters are justified. It is shown that by increasing the number of digital-analog sections, it is possible to repeatedly increase the information capacity of a multi-sensor Converter without tightening the requirements for its manufacturing technology and element base. A mathematical model of the proposed Converter is developed that reflects the features of its operation in the mode of sequential time conversion of the input code vectors of individual fiber-optic sections into electrical analogues and the formation of the resulting output code vector.


2020 ◽  
Vol 11 (1) ◽  
pp. 59-85
Author(s):  
Cletus Famous Nwankwo

AbstractThis paper examines the effect of rurality on party system fragmentation in the Nigerian presidential elections of the fourth republic. The findings show that party system fragmentation (PSF) has been characteristically low in the Nigerian presidential elections and rurality does not significantly predict party system fragmentation. Rurality has a negative effect on PSF in all the elections studied except the 2003 election but only significant in the 2011 poll. Thus, the paper cast doubt on previous studies that indicate that striking rural-urban differences manifest in party system fragmentation in African elections and attribute it to previous studies’ measure of rurality. The paper argues that the use of a composite measure of rurality instead of singular measures of rurality might provide better analysis that helps us understand the effect of rurality on party systems. Also, it argues that in the study of the rural-urban difference in voting behaviour or political behaviours more broadly, data should be aggregated based on cities and non-city areas because cities have distinctive urban characters compared with non-city places. Analyses done on states or constituencies level may not reveal the rural-urban difference because states and constituencies usually have a mix of rural and urban population and other characteristics.


2021 ◽  
Vol 11 (16) ◽  
pp. 7199
Author(s):  
Dapu Pi ◽  
Juan Liu

In this article, we propose a reference light wave multiplexing scheme to increase the information capacity of computer-generated holograms. The holograms were generated by different reference light waves and superimposed together as a multiplexed hologram. A modified Gerchberg–Saxton algorithm was used to improve image quality, and different images could be reconstructed when the multiplexed hologram was illuminated by corresponding reference light waves. We performed both numerical simulations and optical experiments to demonstrate the feasibility of the proposed scheme. Numerical simulations showed that the proposed method could reconstruct multiple images successfully by a single multiplexed hologram and optical experiments are consistently good with numerical simulations. It is expected that the proposed method has great potential to be widely applied in holographic displays in the future.


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