We identify the precise hallmarks of the local magnetic moment formation and its Kondo screening in the frequency structure of the generalized charge susceptibility. The sharpness of our ...identification even pinpoints an alternative criterion to determine the Kondo temperature of strongly correlated systems on the two-particle level, which only requires calculations at the lowest Matsubara frequency. We showcase its strength by applying it to the single impurity and the periodic Anderson model as well as to the Hubbard model. Our results represent a significant progress for the general understanding of quantum field theory at the two-particle level and allow for tracing the limits of the physics captured by perturbative approaches for correlated systems.
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Persistent luminescence is not affected by background autofluorescence, and thus holds the promise of high-contrast bioimaging. However, at present, persistent luminescent materials for in vivo ...imaging are mainly bulk crystals characterized by a non-uniform size and morphology, inaccessible core-shell structures and short emission wavelengths. Here we report a series of X-ray-activated, lanthanide-doped nanoparticles with an extended emission lifetime in the second near-infrared window (NIR-II, 1,000-1,700 nm). Core-shell engineering enables a tunable NIR-II persistent luminescence, which outperforms NIR-II fluorescence in signal-to-noise ratios and the accuracy of in vivo multiplexed encoding and multilevel encryption, as well as in resolving mouse abdominal vessels, tumours and ureters in deep tissue (~2-4 mm), with up to fourfold higher signal-to-noise ratios and a threefold greater sharpness. These rationally designed nanoparticles also allow the high-contrast multiplexed imaging of viscera and multimodal NIR-II persistent luminescence-magnetic resonance-positron emission tomography imaging of murine tumours.
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34.
MedGAN: Medical image translation using GANs Armanious, Karim; Jiang, Chenming; Fischer, Marc ...
Computerized medical imaging and graphics,
January 2020, 2020-Jan, 2020-01-00, 20200101, Volume:
79
Journal Article
Peer reviewed
Open access
•MedGAN as a new end-to-end framework for medical image translation.•Combination of cGAN with non-adversarial losses and a new generator architecture.•Application on several medical tasks with no ...modifications to the hyperparameters.•MedGAN outperforms other approaches in qualitative and quantitative comparisons.•Perceptual evaluation was performed by five experienced radiologists.
Image-to-image translation is considered a new frontier in the field of medical image analysis, with numerous potential applications. However, a large portion of recent approaches offers individualized solutions based on specialized task-specific architectures or require refinement through non-end-to-end training. In this paper, we propose a new framework, named MedGAN, for medical image-to-image translation which operates on the image level in an end-to-end manner. MedGAN builds upon recent advances in the field of generative adversarial networks (GANs) by merging the adversarial framework with a new combination of non-adversarial losses. We utilize a discriminator network as a trainable feature extractor which penalizes the discrepancy between the translated medical images and the desired modalities. Moreover, style-transfer losses are utilized to match the textures and fine-structures of the desired target images to the translated images. Additionally, we present a new generator architecture, titled CasNet, which enhances the sharpness of the translated medical outputs through progressive refinement via encoder-decoder pairs. Without any application-specific modifications, we apply MedGAN on three different tasks: PET-CT translation, correction of MR motion artefacts and PET image denoising. Perceptual analysis by radiologists and quantitative evaluations illustrate that the MedGAN outperforms other existing translation approaches.
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Defocus blur detection is an important and challenging task in computer vision and digital imaging fields. Previous work on defocus blur detection has put a lot of effort into designing local ...sharpness metric maps. This paper presents a simple yet effective method to automatically obtain the local metric map for defocus blur detection, which based on the feature learning of multiple convolutional neural networks (ConvNets). The ConvNets automatically learn the most locally relevant features at the super-pixel level of the image in a supervised manner. By extracting convolution kernels from the trained neural network structures and processing it with principal component analysis, we can automatically obtain the local sharpness metric by reshaping the principal component vector. Meanwhile, an effective iterative updating mechanism is proposed to refine the defocus blur detection result from coarse to fine by exploiting the intrinsic peculiarity of the hyperbolic tangent function. The experimental results demonstrate that our proposed method consistently performed better than the previous state-of-the-art methods.
Quiet Daytime Arctic Ionospheric D Region Thomson, Neil R.; Clilverd, Mark A.; Rodger, Craig J.
Journal of geophysical research. Space physics,
November 2018, 2018-11-00, 20181101, Volume:
123, Issue:
11
Journal Article
Peer reviewed
Open access
Phase and amplitude measurements of VLF radio waves propagating subionospherically on long paths across the Arctic are used to determine the high latitude, daytime D region height, and sharpness of ...the bottom edge of the Earth's ionosphere. The principal path used is from the 23.4‐kHz transmitter, DHO, in north Germany, northward across the Arctic passing ~2° from the North Pole, and then southward to Nome, Alaska, thus avoiding most land and all thick ice. Significant observational support is obtained from the also nearly all‐sea path from JXN in Norway (~67°N, 16.4 kHz) across the North Pole to Nome. By suitably comparing measurements with modeling using the U.S. Navy code LWPC, the daytime D region (Wait) height and sharpness parameters in the Arctic are found to be H′ = 73.7 ± 0.7 km and β = 0.32 ± 0.02 km−1 in the summer of 2013, that is, at (weak) solar maximum. It is also found that, unlike at lower latitudes, very low frequency phase and amplitude recordings on (~1,000 km) paths at high subarctic latitudes show very little change with solar zenith angle in both phase and amplitude during daytime for solar zenith angles <~80°. It is concluded that, at high latitudes, the daytime lower D region is dominated by nonsolar ionizing sources in particular by energetic particle precipitation (>~300 keV for electrons) with a contribution from galactic cosmic rays, rather than by solar Lyman α which dominates at low and middle latitudes.
Key Points
Daytime Arctic ionospheric D region height and sharpness measured as 73.7 km and 0.32 km−1 using long VLF radio path Germany to Alaska
Daytime Arctic D region largely independent of solar zenith angle unlike at lower latitudes where solar Lyman alpha dominates
Energetic particle precipitation is just dominant over galactic cosmic rays and solar Lyman alpha in the quiet daytime Arctic D region
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Since the inception of competitive power markets two decades ago, electricity price forecasting (EPF) has gradually become a fundamental process for energy companies’ decision making mechanisms. Over ...the years, the bulk of research has concerned point predictions. However, the recent introduction of smart grids and renewable integration requirements has had the effect of increasing the uncertainty of future supply, demand and prices. Academics and practitioners alike have come to understand that probabilistic electricity price (and load) forecasting is now more important for energy systems planning and operations than ever before. With this paper we offer a tutorial review of probabilistic EPF and present much needed guidelines for the rigorous use of methods, measures and tests, in line with the paradigm of ‘maximizing sharpness subject to reliability’. The paper can be treated as an update and a further extension of the otherwise comprehensive EPF review of Weron 1 or as a standalone treatment of a fascinating and underdeveloped topic, that has a much broader reach than EPF itself.
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The number of components of a thermographic temperature measurement uncertainty budget and their ultimate contribution depend on the conditions in which the measurement is performed. The acquired ...data determine the accuracy with which the uncertainty component is estimated. Unfortunately, when some factors have to be taken into account, it is difficult to determine the value of the uncertainty component caused by the occurrence of this factor. In the case of a thermographic temperature measurement, such a factor is the lack of sharpness of the registered thermogram. This problem intensifies when an additional macro lens must be used. Therefore, it is decided to commence research to prepare an uncertainty budget of thermographic measurement with an additional macro lens based on the B method described in EA-4/02 (European Accreditation publications). As a result, the contribution of factors in the uncertainty budget of thermographic measurement with additional macro lens and the value of expanded uncertainty were obtained.
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Underwater images suffer from blurring effects, low contrast, and grayed out colors due to the absorption and scattering effects under the water. Many image enhancement algorithms for improving the ...visual quality of underwater images have been developed. Unfortunately, no well-accepted objective measure exists that can evaluate the quality of underwater images similar to human perception. Predominant underwater image processing algorithms use either a subjective evaluation, which is time consuming and biased, or a generic image quality measure, which fails to consider the properties of underwater images. To address this problem, a new nonreference underwater image quality measure (UIQM) is presented in this paper. The UIQM comprises three underwater image attribute measures: the underwater image colorfulness measure (UICM), the underwater image sharpness measure (UISM), and the underwater image contrast measure (UIConM). Each attribute is selected for evaluating one aspect of the underwater image degradation, and each presented attribute measure is inspired by the properties of human visual systems (HVSs). The experimental results demonstrate that the measures effectively evaluate the underwater image quality in accordance with the human perceptions. These measures are also used on the AirAsia 8501 wreckage images to show their importance in practical applications.
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