Freedom of Information and Personal Confidentiality in Spatial COVID-19 Data

We draw attention to how, in the name of protecting the confidentiality of personal data, national statistical agencies have limited public access to spatial data on COVID-19. We also draw attention to large disparities in the way that access has been limited. In doing so, we distinguish between absolute confidentiality in which the probability of detection is 1, relative confidentiality where this probability is less than 1, and collective confidentiality, which refers to the probability of detection of at least one person. In spatial data, the probability of personal detection is less than 1, and the probability of collective detection varies directly with this probability and COVID-19 morbidity. Statistical agencies have been concerned with relative and collective confidentiality, which they implement using the techniques of truncation, where spatial data are not made public for zones with small populations, and censoring, where exact data are not made public for zones where morbidity is small. Granular spatial data are essential for epidemiological research into COVID-19. We argue that in their reluctance to make these data available to the public, data security officers (DSO) have unreasonably prioritized data protection over freedom of information. We also argue that by attaching importance to relative and collective confidentiality, they have over-indulged in data truncation and censoring. We highlight the need for legislation concerning relative and collective confidentiality, and regulation of DSO practices regarding data truncation and censoring.

Study of the truncation strategy in the FPGA of a solar radio digital receiver

Computation resource is the limiting factor in higher operational accuracy of field-programmable gate arrays (FPGAs) in solar radio digital receivers. The data truncation strategy which determines the accuracy of data is then the essential technology in the design of a receiving system. Based on the solar radio spectrometer (dual channel, 14 bit, 1.25 gigasamples per second) at the Chashan Solar Radio Observatory (CSO), this paper presents a data truncation strategy which can realize real-time solar radio observation (35–40 GHz) with high time and frequency resolution as well as a large dynamic range, and at the same time saves the computation resource to a large extent. Simulations of truncations during signal processing are carried out in MATLAB, and the best truncation mechanisms are deduced for windowing and fast Fourier transform (FFT). Using the simulation results, the best truncation strategies have been implemented in the solar radio receiver at CSO with the result that the best truncation bits for the windowing operation are [27 : 14], with an error of 2.5 × 10−4, and the best truncation bits for the FFT output are [20 : 5] with an error of 1.5 × 10−3. Compared with the processing of full-precision data, occupation of the computation resources in the FPGA can be reduced significantly. For instance, the lookup table, lookup table RAM, flip flop, and digital signal processing slices are reduced by 7.36%, 14.65%, 8.38%, and 24.94%, respectively, which guarantees broad-band real-time solar radio observations (35–40 GHz).

English Slang in “Gap Year” Movies Series

This research discussed about the slang words in Gap Year movie series and the word formation of the slang words which were found in the movie series. Slang itself was used by certain group or community, which could be produced by compounding, affixation, truncation, conversion, blending, neologism, etymology, borrowing, coinage, and multiple processes. This research used a qualitative method. In this research, the data were collected from Gap Year movie series in the form of British slangs.Then the data were checked by using dictionary, Oxford English Dictionaries Online and Etymology dictionaries online to make sure whether the data belonged to slang words or not and also to check the origin of the words. The data were also analyzed based on Plag and Yule’s theories in terms of etymology, borrowing, coinage, and multiple processes. After collecting the data, there were 30 slang words found in this movie series. The result of the research showed that the slangs were formed through compounding (8 data), affixation (5 data), truncation (1 data), blending (2 data), etymology (9 data), borrowing (1 data), coinage (2 data), and multiple process (2 data). Therefore, the most used of word formation process was etymology.

A metal artifact reduction method for small field of view CT imaging

Several sinogram inpainting based metal artifact reduction (MAR) methods have been proposed to reduce metal artifact in CT imaging. The sinogram inpainting method treats metal trace regions as missing data and estimates the missing information. However, a general assumption with these methods is that data truncation does not occur and that all metal objects still reside within the field-of-view (FOV). These assumptions are usually violated when the FOV is smaller than the object. Thus, existing inpainting based MAR methods are not effective. In this paper, we propose a new MAR method to effectively reduce metal artifact in the presence of data truncation. The main principle of the proposed method involves using a newly synthesized sinogram instead of the originally measured sinogram. The initial reconstruction step involves obtaining a small FOV image with the truncation artifact removed. The final step is to conduct sinogram inpainting based MAR methods, i.e., linear and normalized MAR methods, on the synthesized sinogram from the previous step. The proposed method was verified for extended cardiac-torso simulations, clinical data, and experimental data, and its performance was quantitatively compared with those of previous methods (i.e., linear and normalized MAR methods directly applied to the originally measured sinogram data). The effectiveness of the proposed method was further demonstrated by reducing the residual metal artifact that were present in the reconstructed images obtained using the previous method.

Finite element algorithms for nonlocal minimal graphs

<abstract><p>We discuss computational and qualitative aspects of the fractional Plateau and the prescribed fractional mean curvature problems on bounded domains subject to exterior data being a subgraph. We recast these problems in terms of energy minimization, and we discretize the latter with piecewise linear finite elements. For the computation of the discrete solutions, we propose and study a gradient flow and a Newton scheme, and we quantify the effect of Dirichlet data truncation. We also present a wide variety of numerical experiments that illustrate qualitative and quantitative features of fractional minimal graphs and the associated discrete problems.</p></abstract>

A metal artifact reduction method for small field of view CT imaging

To reduce metal artifacts, several sinogram inpainting-based metal artifact reduction (MAR) methods have been proposed where projection data within the metal trace region of the sinogram are treated as missing and subsequently estimated. However, these methods generally assume data truncation does not occur and all metal objects reside inside the field-of-view (FOV). For small FOV imaging, these assumptions are violated, and thus existing inpainting-based MAR methods would not be effective. In this paper, we propose a new MAR method to reduce metal artifacts effectively in the presence of data truncation. The main idea behind the proposed method is the synthesis of a sinogram, which is treated as the originally measured sinogram. First, an initial reconstruction step is performed to remove truncation artifacts. The next step consists of a forward projection of the small FOV image, replacing the original sinogram with the synthesized sinogram. The final step is the application of sinogram inpainting based MAR methods using the synthesized sinogram. Verification of the proposed method was performed for three situations: extended cardiac-torso (XCAT) simulation, clinical data, and experimental data. The proposed method was applied with linear MAR (LMAR) and normalized MAR (NMAR), and the performance of the proposed method was compared with that of the previous method. For quantitative evaluation, normalized mean squared error (NMSE) and structure similarity (SSIM) were used. The results show the effectiveness of the proposed method to reduce residual metal artifacts, which are present in the results obtained with the previous method. The evaluation results using NMSE and SSIM also indicate that the proposed method is more effective than the previous method.