1,721,002 research outputs found
Secure Random Phase Key Exchange Schemes for Image Cryptography
No full textWe propose novel random phase key exchange schemes for image cryptography, which are complex sinusoidal waveform versions of the Diffie-Hellman (DH) key exchange algorithm. We demonstrate that the proposed schemes can be particularly helpful to establish a shared secret key in Fourier optics-based image cryptosystems since the problem of symmetric secret key establishment is one of the fundamental difficulties in Fourier optics-based image cryptography. We also propose a ring-type key exchange system in which multiple users can securely share a secret key, which is an extension of the key exchange scheme for two users. The schemes are verified by numerical simulations. © 2014 IEEE.1
No-search focus prediction at the single cell level in digital holographic imaging with deep convolutional neural network
Full text linkDigital propagation of an off-axis hologram can provide the quantitative phase-contrast image if the exact distance between the sensor plane (such as CCD) and the reconstruction plane is correctly provided. In this paper, we present a deep-learning convolutional neural network with a regression layer as the top layer to estimate the best reconstruction distance. The experimental results obtained using microsphere beads and red blood cells show that the proposed method can accurately predict the propagation distance from a filtered hologram. The result is compared with the conventional automatic focus-evaluation function. Additionally, our approach can be utilized at the single-cell level, which is useful for cell-to-cell depth measurement and cell adherent studies. © 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.1
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Deep Learning-based Cryptanalysis on Double Random Phase Encoding
No full textWe overview deep learning-based cryptanalysis schemes on DRPE, which find the weakness of the DRPE by classifying the DRPE images. We show the classification performance is almost the same as the original image. © 2023 The Author (s)
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
New approaches for real-time automated three-dimensional sensing, visualization, and identification of biological microorganisms
No full textThe study of harmful micro/nano biological organisms or other specimens has many potential applications in security and defense or novel disease detection. Therefore, developing reliable, automated, and low-cost methods for real-time sensing, visualization, and identification of harmful pathogens or biological cells are essential in combating catastrophic diseases or for new medical treatments. The optical imaging systems using digital holography have been extensively investigated for three-dimensional (3D) visualization and recognition of rigid objects. In contrast, biological specimens have dynamic activities such as moving, dividing and growing. Consequently, these issues make it difficult to three-dimensionally visualize biological specimens. Moreover, many specimens such as cell parts in protozoans, bacteria, and sperm tails are essentially fully transparent unless stained, killing the specimens. Accordingly, it is insufficient to use the 2D profile of them based on image intensity for their visualization or identification. Phase-contrast techniques have been developed for the non-invasive visualization of the transparent specimens because the difference in densities and composition within them give rise to changes in the phase of light passing through them. ^ This thesis presents a novel methodology for 3D sensing, imaging, and identification of micro/nano biological organisms. The proposed digital holographic systems provide a real-time 3D recording and visualization of specimens. Statistical pattern recognition algorithms are developed for the optimum classification of specimens. This methodology aims at identifying the 3D images reconstructed from the digital holograms of specimens and recognizing very minute differences in thickness, size, and shape. This methodology develops into the white light in-line (WLI) digital holographic system that has much simple, practical optical setup. The major advantages of the proposed WLI digital holographic system are that it can analyze specimen across the entire spectrum and requires very simple, practical optical setups for 3D recording. In addition, optimal spatial resolution can be obtained by using shorter or applicable wavelengths. The methodologies and algorithms addressed in this thesis are believed to be substantial progress for the automated identification of transparent biological specimens. To the best of the knowledge of the author, this is the first report on using 3D holographic imaging data for optoelectronic identification of micro/nano biological organisms.
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