3,012 research outputs found

    Spectral imaging of human portraits and image quality

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    This dissertation addresses the problem of capturing spectral images for human portraits and evaluating image quality of spectral images. A new spectral imaging approach is proposed in this dissertation for spectral images of human portraits. Thorough statistical analysis is performed for spectral reflectances from various races and different face parts. A spectral imaging system has been designed and calibrated for human portraits. The calibrated imaging system has the ability to represent not only the facial skin but also the spectra of lips, eyes and hair from various races as well. The generated spectral images can be applied to color-imaging system design and analysis. To evaluate the image quality of spectral imaging systems, a visual psychophysical image quality experiment has been performed in this dissertation. The spectral images were simulated based on real spectral imaging system. Meaningful image quality results have been obtained for spectral images generated from different spectral imaging systems. To bridge the gap between the physical measures and subjective visual perceptions of image quality, four image distortion factors were defined. Image quality metrics were obtained and evaluated based statistical analysis and multiple analysis. The image quality metrics have high correlation with subjective assessment for image quality. The image quality contribution of the distortion factors were evaluated. As an extension of the work other researchers in MCSL have initiated, this dissertation research will, working with other researchers in MCSL, put effort to build a publicly accessible database of spectral images, Lippmann2000

    Does High-tech Export Cause More Technology Spillover? Evidence from Contemporary China

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    This paper attempts to investigate whether high-tech product export causes more technology spillover compared with traditionally primary manufactured goods export.A generalized multi-sector spillover model is presented to involve the causations of export composition and technology spillover, which is based on two distinctive approaches of measuring technology spillover: “between-spillover” and “within-spillover”. The empirical estimation is conducted with a panel analysis involving 31 provinces in China over the period of 1998-2005. Although high-tech export sectors involve a higher productivity compared with other sectors, this productivity advantage in high-tech export sectors does not cause technology spillover towards both domestic sectors and other export sectors. Therefore, this paper suggests that technology spillover of export mainly takes place in traditional export sectors rather than high-tech export sectors.Export Composition; High-tech Export; Technology Spillover; Multi-sector Spillover Model

    Application of PQS for image quality analysis in visible spectral imaging

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    An image quality investigation in visible spectral imaging was performed. Spectral images were simulated using different number of imaging channels, wavelength steps, and noise levels based on practical spectral imaging systems. A mean opinion score (MOS) was determined from a subjective visual assessment scale experiment for image quality of spectral images rendered to a three-channel display. A set of partial image distortion measures, including color difference for color images, were defined based on classified and quantified actual distortions produced by spectral imaging systems. Principal components analysis was then carried out to quantify the correlation between distortion factors. Finally, a multiple regression analysis (MRA) was carried out between the principal component vectors and the measured MOS values to determine the picture quality scale (PQS). The obtained quality metric, PQS, had high correlation with the subjective measure, MOS. The importance of contribution of the distortion factors in the image quality metric was also evaluated

    The Pragmatic Function of Vague Language in Business Letters Guided by the Relevance Theory

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    Trade between China and foreign countries is increasingly frequent. As the medium of communication, business letters are playing a more and more important role in trading. It is easy to find that vague language is widely used in business letters. The successful use of vague language requires the recipient to be able to infer the writer’s intention correctly. This paper takes business letters collected online and offline as corpus, and will analyze the vague language from two aspects, that is, lexical aspect and syntactic aspect. Based on the analysis finally summarize the three main pragmatic functions of vague language in business letters, namely intent expression, self-protection and politeness

    Electrical Control of Magnetization in Charge-ordered Multiferroic LuFe2O4

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    LuFe2O4 exhibits multiferroicity due to charge order on a frustrated triangular lattice. We find that the magnetization of LuFe2O4 in the multiferroic state can be electrically controlled by applying voltage pulses. Depending on with or without magnetic fields, the magnetization can be electrically switched up or down. We have excluded thermal heating effect and attributed this electrical control of magnetization to an intrinsic magnetoelectric coupling in response to the electrical breakdown of charge ordering. Our findings open up a new route toward electrical control of magnetization.Comment: 14 pages, 5 figure

    miR-181a increases FoxO1 acetylation and promotes granulosa cell apoptosis via SIRT1 downregulation.

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    Oxidative stress impairs follicular development by inducing granulosa cell (GC) apoptosis, which involves enhancement of the transcriptional activity of the pro-apoptotic factor Forkhead box O1 (FoxO1). However, the mechanism by which oxidative stress promotes FoxO1 activity is still unclear. Here, we found that miR-181a was upregulated in hydrogen peroxide (
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