265 research outputs found

    Estudio sobre la relación entre la personalidad y el comportamiento de intercambio de conocimientos basado en la moderación de la situación de gobernanza del conocimiento

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    In an organization, people’s knowledge sharing behavior is not only related to their personality traits but also regulated by the knowledge governance situation of their organizations. This paper demonstrates the intrinsic relationship between the big five personalities, the knowledge sharing the behaviour of the organization and the situation of knowledge governance, establishes a construct model of the big five personalities as the independent variable, the knowledge sharing behavior as the dependent variable and the knowledge governance situation as the moderator variable. The questionnaire was used to collect the scale data and the HLM model was used to test the relevant hypotheses. The results show that different personality traits have different correlations with knowledge sharing behavior, and knowledge governance situation has a moderating effect on the relationship between personality traits and knowledge sharing behavior.En una organización, el comportamiento de intercambio de conocimiento de las personas no solo está relacionado con sus rasgos de personalidad, sino que también está regulado por la situación de gobernanza del conocimiento de sus organizaciones. Este artículo demuestra la relación intrínseca entre las cinco grandes personalidades, el conocimiento que comparte el comportamiento de la organización y la situación de la gobernanza del conocimiento, establece un modelo constructivo de las cinco grandes personalidades como la variable independiente, el comportamiento del intercambio de conocimiento como la variable dependiente y La situación de gobernanza del conocimiento como variable moderadora. El cuestionario se usó para recolectar los datos de la escala y el modelo HLM se usó para probar las hipótesis relevantes. Los resultados muestran que diferentes rasgos de personalidad tienen diferentes correlaciones con el comportamiento de intercambio de conocimiento, y la situación de gobernanza del conocimiento tiene un efecto moderador en la relación entre los rasgos de personalidad y el comportamiento de intercambio de conocimiento

    Single-shot stereo-polarimetric compressed ultrafast photography for light-speed observation of high-dimensional optical transients with picosecond resolution

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    Simultaneous and efficient ultrafast recording of multiple photon tags contributes to high-dimensional optical imaging and characterization in numerous fields. Existing high-dimensional optical imaging techniques that record space and polarization cannot detect the photon’s time of arrival owing to the limited speeds of the state-of-the-art electronic sensors. Here, we overcome this long-standing limitation by implementing stereo-polarimetric compressed ultrafast photography (SP-CUP) to record light-speed high-dimensional events in a single exposure. Synergizing compressed sensing and streak imaging with stereoscopy and polarimetry, SP-CUP enables video-recording of five photon tags (x, y, z: space; t: time of arrival; and ψ: angle of linear polarization) at 100 billion frames per second with a picosecond temporal resolution. We applied SP-CUP to the spatiotemporal characterization of linear polarization dynamics in early-stage plasma emission from laser-induced breakdown. This system also allowed three-dimensional ultrafast imaging of the linear polarization properties of a single ultrashort laser pulse propagating in a scattering medium

    Single-shot real-time femtosecond imaging of temporal focusing

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    While the concept of focusing usually applies to the spatial domain, it is equally applicable to the time domain. Real-time imaging of temporal focusing of single ultrashort laser pulses is of great significance in exploring the physics of the space–time duality and finding diverse applications. The drastic changes in the width and intensity of an ultrashort laser pulse during temporal focusing impose a requirement for femtosecond-level exposure to capture the instantaneous light patterns generated in this exquisite phenomenon. Thus far, established ultrafast imaging techniques either struggle to reach the desired exposure time or require repeatable measurements. We have developed single-shot 10-trillion-frame-per-second compressed ultrafast photography (T-CUP), which passively captures dynamic events with 100-fs frame intervals in a single camera exposure. The synergy between compressed sensing and the Radon transformation empowers T-CUP to significantly reduce the number of projections needed for reconstructing a high-quality three-dimensional spatiotemporal datacube. As the only currently available real-time, passive imaging modality with a femtosecond exposure time, T-CUP was used to record the first-ever movie of non-repeatable temporal focusing of a single ultrashort laser pulse in a dynamic scattering medium. T-CUP’s unprecedented ability to clearly reveal the complex evolution in the shape, intensity, and width of a temporally focused pulse in a single measurement paves the way for single-shot characterization of ultrashort pulses, experimental investigation of nonlinear light-matter interactions, and real-time wavefront engineering for deep-tissue light focusing

    The Devil of Face Recognition is in the Noise

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    The growing scale of face recognition datasets empowers us to train strong convolutional networks for face recognition. While a variety of architectures and loss functions have been devised, we still have a limited understanding of the source and consequence of label noise inherent in existing datasets. We make the following contributions: 1) We contribute cleaned subsets of popular face databases, i.e., MegaFace and MS-Celeb-1M datasets, and build a new large-scale noise-controlled IMDb-Face dataset. 2) With the original datasets and cleaned subsets, we profile and analyze label noise properties of MegaFace and MS-Celeb-1M. We show that a few orders more samples are needed to achieve the same accuracy yielded by a clean subset. 3) We study the association between different types of noise, i.e., label flips and outliers, with the accuracy of face recognition models. 4) We investigate ways to improve data cleanliness, including a comprehensive user study on the influence of data labeling strategies to annotation accuracy. The IMDb-Face dataset has been released on https://github.com/fwang91/IMDb-Face.Comment: accepted to ECCV'1

    Label-free high-throughput photoacoustic tomography of suspected circulating melanoma tumor cells in patients in vivo

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    Significance: Detection and characterization of circulating tumor cells (CTCs), a key determinant of metastasis, are critical for determining risk of disease progression, understanding metastatic pathways, and facilitating early clinical intervention. Aim: We aim to demonstrate label-free imaging of suspected melanoma CTCs. Approach: We use a linear-array-based photoacoustic tomography system (LA-PAT) to detect melanoma CTCs, quantify their contrast-to-noise ratios (CNRs), and measure their flow velocities in most of the superficial veins in humans. Results: With LA-PAT, we successfully imaged suspected melanoma CTCs in patients in vivo, with a CNR >9. CTCs were detected in 3 of 16 patients with stage III or IV melanoma. Among the three CTC-positive patients, two had disease progression; among the 13 CTC-negative patients, 4 showed disease progression. Conclusions: We suggest that LA-PAT can detect suspected melanoma CTCs in patients in vivo and has potential clinical applications for disease monitoring in melanoma

    Multiview optical resolution photoacoustic microscopy

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    Optical resolution photoacoustic microscopy (OR-PAM), while providing high lateral resolution, has been limited by its relatively poor acoustically determined axial resolution. Although this limitation has been tackled in recent works by using either broadband acoustic detection or nonlinear photoacoustic effects, a flexible solution with three-dimensional optical resolution in reflection mode remains desired. Herein we present a multiview OR-PAM technique. By imaging the sample from multiple view angles and reconstructing the data using a multiview deconvolution method, we have experimentally demonstrated an isotropic optical resolution in three dimensions

    Multiview Hilbert transformation in full-ring transducer array-based photoacoustic computed tomography

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    Based on the photoacoustic (PA) effect, PA tomography directly measures specific optical absorption, i.e., absorbed optical energy per unit volume. We recently developed a full-ring ultrasonic transducer array-based photoacoustic computed tomography (PACT) system for small-animal whole-body imaging. The system has a full-view detection angle and high in-plane resolution (∼100  μm). However, due to the bandpass frequency response of the piezoelectric transducer elements and the limited elevational detection coverage of the full-ring transducer array, the reconstructed images present bipolar (i.e., both positive and negative) pixel values, which cause ambiguities in image interpretation for physicians and biologists. We propose a multiview Hilbert transformation method to recover the unipolar initial pressure for full-ring PACT. The effectiveness of the proposed algorithm was first validated by numerical simulations and then demonstrated with ex vivo mouse brain structural imaging and in vivo mouse whole-body imaging
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