910 research outputs found

    Impact of Butterfly Wing-Pitch Interaction on Flight Performance

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    The 11th International Symposium on Adaptive Motion of Animals and Machines. Kobe University, Japan. 2023-06-06/09. Adaptive Motion of Animals and Machines Organizing Committee.Poster Session P2

    Investigation of Effects of Strouhal and Reynolds numbers on Propulsive Efficiency of Plunging and Pitching Foils

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    The 11th International Symposium on Adaptive Motion of Animals and Machines. Kobe University, Japan. 2023-06-06/09. Adaptive Motion of Animals and Machines Organizing Committee.Poster Session P2

    Hyper-Restormer: A General Hyperspectral Image Restoration Transformer for Remote Sensing Imaging

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    The deep learning model Transformer has achieved remarkable success in the hyperspectral image (HSI) restoration tasks by leveraging Spectral and Spatial Self-Attention (SA) mechanisms. However, applying these designs to remote sensing (RS) HSI restoration tasks, which involve far more spectrums than typical HSI (e.g., ICVL dataset with 31 bands), presents challenges due to the enormous computational complexity of using Spectral and Spatial SA mechanisms. To address this problem, we proposed Hyper-Restormer, a lightweight and effective Transformer-based architecture for RS HSI restoration. First, we introduce a novel Lightweight Spectral-Spatial (LSS) Transformer Block that utilizes both Spectral and Spatial SA to capture long-range dependencies of input features map. Additionally, we employ a novel Lightweight Locally-enhanced Feed-Forward Network (LLFF) to further enhance local context information. Then, LSS Transformer Blocks construct a Single-stage Lightweight Spectral-Spatial Transformer (SLSST) that cleverly utilizes the low-rank property of RS HSI to decompose the feature maps into basis and abundance components, enabling Spectral and Spatial SA with low computational cost. Finally, the proposed Hyper-Restormer cascades several SLSSTs in a stepwise manner to progressively enhance the quality of RS HSI restoration from coarse to fine. Extensive experiments were conducted on various RS HSI restoration tasks, including denoising, inpainting, and super-resolution, demonstrating that the proposed Hyper-Restormer outperforms other state-of-the-art methods

    Nonlinear photoacoustic microscopy via a loss modulation technique: from detection to imaging

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    In order to achieve high-resolution deep-tissue imaging, multi-photon fluorescence microscopy and photoacoustic tomography had been proposed in the past two decades. However, combining the advantages of these two imaging systems to achieve optical-spatial resolution with an ultrasonic-penetration depth is still a field with challenges. In this paper, we investigate the detection of the two-photon photoacoustic ultrasound, and first demonstrate background-free two-photon photoacoustic imaging in a phantom sample. To generate the background-free two-photon photoacoustic signals, we used a high-repetition rate femtosecond laser to induce narrowband excitation. Combining a loss modulation technique, we successfully created a beating on the light intensity, which not only provides pure sinusoidal modulation, but also ensures the spectrum sensitivity and frequency selectivity. By using the lock-in detection, the power dependency experiment validates our methodology to frequency-select the source of the nonlinearity. This ensures our capability of measuring the background-free two-photon photoacoustic waves by detecting the 2nd order beating signal directly. Furthermore, by mixing the nanoparticles and fluorescence dyes as contrast agents, the two-photon photoacoustic signal was found to be enhanced and detected. In the end, we demonstrate subsurface two-photon photoacoustic bio-imaging based on the optical scanning mechanism inside phantom samples

    In vivo sub-femtoliter resolution photoacoustic microscopy with higher frame rates

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    Microscopy based on non-fluorescent absorption dye staining is widely used in various fields of biomedicine for 400 years. Unlike its fluorescent counterpart, non-fluorescent absorption microscopy lacks proper methodologies to realize its in vivo applications with a sub-femtoliter 3D resolution. Regardless of the most advanced high-resolution photoacoustic microscopy, sub-femtoliter spatial resolution is still unattainable, and the imaging speed is relatively slow. In this paper, based on the two-photon photoacoustic mechanism, we demonstrated a in vivo label free laser-scanning photoacoustic imaging modality featuring high frame rates and sub-femtoliter 3D resolution simultaneously, which stands as a perfect solution to 3D high resolution non-fluorescent absorption microscopy. Furthermore, we first demonstrated in vivo label-free two-photon acoustic microscopy on the observation of non-fluorescent melanin distribution within mouse skin

    Establishing nanoscale heterogeneity with nanoscale force measurements

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    Establishing the presence or absence of nanoscale compositional heterogeneity with nanoscale resolution is becoming instrumental for the development of many fields of science. Force versus distance measurements and parameters directly or indirectly derived from these profiles can be potentially employed for this purpose with sophisticated instruments such as the atomic force microscope (AFM). On the other hand, standards are necessary to reproducibly and conclusively support hypothesis from experimental data and these standards are still emerging. Here, we define a set of standards for providing data originating from atomic force measurements to be employed to compare between sample properties, parameters, or, more generally, compositional heterogeneity. We show that reporting the mean and standard deviation only might lead to inconsistent conclusions. The fundamental principle behind our investigation deals with the very definition of reproducibility and repeatability in terms of accuracy and precision, and we establish general criteria to ensure that these hold without the need of restricting assumptions.Postprint (author’s final draft

    Predicting the suitability of lateritic soil type for low cost sustainable housing with image recognition and machine learning techniques

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    From a sustainability point of view, laterites-compressed earth bricks (LCEB) are a promising substitute for building structures in place of the conventional concrete masonry units. On the other hand, techniques for identifying and classifying laterites soil for compressed earth bricks (CEB) production are still relying on direct human expertise or ‘experts’. Human experts exploit direct visual inspection and other basic senses such as smelling, touching or nibbling to generate a form of binomial classification, i.e. suitable or unsuitable. The source of predictive power is otherwise supposed to be found in color, scent, texture or combinations of these. Lack of clarity regarding the actual method and the possible explanatory mechanisms lead to 1) difficulties to train other people into the skills and 2) might also add to apathy to using CEB masonry units for housing. Here we systematize the selection method of experts. We chose imaging analysis techniques based on 1) easiness in image acquisition (Digital Camera) and 2) availability of machine learning and statistical techniques. We find that most of the predictive power of the ‘expert’ can be packed into visual inspection by demonstrating that with image analysis alone we get a 98% match. This makes it practically unnecessary the study of any other ‘expert’ skills and provides a method to alleviate the housing problems dealing with material construction in the developing world

    Perturbative QCD analysis of B(B→Xlνˉ)B(B\to Xl\bar{\nu}), charm yield <nc><n_c> in B decay, and τ(Λb)/τ(Bd)\tau (\Lambda_b)/\tau (B_d)

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    We apply perturbative QCD factorization theorems to inclusive heavy hadron decays, and obtain simultaneously a low semileptonic branching ratio B(B→Xlνˉ)=10.16B(B\to Xl\bar{\nu})=10.16%, the average charm yield =1.17=1.17 per BB decay, a small lifetime ratio τ(Λb)/τ(Bd)=0.78\tau(\Lambda_b)/\tau(B_d)=0.78, and the correct absolute decay widths of the BB meson and of the Λb\Lambda_b baryon.Comment: 13 pages in a latex file, numerical results are revised, We obtain B(B→Xlνˉ)=10.16B(B\to Xl\bar{\nu})=10.16%, =1.17=1.17, τ(Λb)/τ(Bd)=0.78\tau(\Lambda_b)/\tau(B_d)=0.78, and the correct absolute decay widths of the BB meson and of the Λb\Lambda_b baryo
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