An Adaptive Characteristic-wise Reconstruction WENOZ scheme for Gas Dynamic Euler Equations

Due to its excellent shock-capturing capability and high resolution, the WENO scheme family has been widely used in varieties of compressive flow simulation. However, for problems containing strong shocks and contact discontinuities, such as the Lax shock tube problem, the WENO scheme still produces numerical oscillations. To avoid such numerical oscillations, the characteristic-wise construction method should be applied. Compared to component-wise reconstruction, characteristic-wise reconstruction leads to much more computational cost and thus is not suite for large scale simulation such as direct numeric simulation of turbulence. In this paper, an adaptive characteristic-wise reconstruction WENO scheme, i.e. the AdaWENO scheme, is proposed to improve the computational efficiency of the characteristic-wise reconstruction method. The new scheme performs characteristic-wise reconstruction near discontinuities while switching to component-wise reconstruction for smooth regions. Meanwhile, a new calculation strategy for the WENO smoothness indicators is implemented to reduce over-all computational cost. Several one dimensional and two dimensional numerical tests are performed to validate and evaluate the AdaWENO scheme. Numerical results show that AdaWENO maintains essentially non-oscillatory flow field near discontinuities as the characteristic-wise reconstruction method. Besieds, compared to the component-wise reconstruction, AdaWENO is about 40\% faster which indicates its excellent efficiency

Spin-resolved (e, 2e) collisions

This thesis presents the results from the triple differential cross section (TDCS) measurements, obtained from an (e,2e) experimental apparatus incorporated with a polarised electron beam source, a polarised sodium atomic beam source, and an electron polarisation polarimeter. The form at of this thesis is in six chapters. Chapter 1 gives a brief introduction to the previous work in this field of research, and the m otivation of the present work. Chapter 2 summarises the theories of electron-impact ionisation with atoms and the electron polarisation phenomena of electron-atom scattering processes. In chapter 3, a detailed description of the experimental apparatus, including the GaAs polarised electron source, the retarding-potential polarimeter, and the (e,2e) spectrometer, is presented. The investigation of spin effects in electron-xenon ionisation processes with a polarised incident electron beam is reported in chapter 4. The transversely polarised incident electron beam has a polarisation of about 24%, and the incident energy was 147 eV. Two outgoing electrons were detected in the same scattering plane of the incident electrons with the (e,2e) coincidence technique. The fast scattered electron with an energy of 100 ± 3 eV was detected at 28°, on the left side of the electron beam, and the ejected electron with an energy of 35 ±3 eV was detected at various angles on the right side of the incident beam. The TDCS for the ground state of Xe+ have been measured with an (e,2e) energy resolution which is sufficient to resolve the two fine structure levels, 5²P½ and 5²P₃/₂. Obvious spin-updown asymmetries for both 5²P½ an d 5²P₃/₂ states were observed with these kinematics. The mechanism of this polarisation phenomenon can be mainly explained by the “fine-structure effect”. Detailed experimental results, comparison with theoretical calculations, and the discussion are given in this chapter. A non-coplanar symmetric (e,2e) experiment with an excited and polarised sodium atomic beam is reported in chapter 5. In this experiment, the electron impact energy was 605 eV. The electron beam (unpolarised), sodium beam, and the laser beam intersected a t right angles in the interaction region. With right-hand circularly polarised laser-light, the sodium atom s w ere aligned and oriented to the excited state , 3p(l = 1, mi = +1). The electron momentum distribution of this state, as well as the randomly oriented ground state 3s, were probed. The experimental results, the comparison theoretical calculations, and the discussion are presented in this chapter. The recent theoretical prediction of orientational (e,2e) dichroism, as well as some experimental techniques are also discussed in this chapter as possible future perspectives. Finally a summary is presented in chapter 6

Artifact Restoration in Histology Images with Diffusion Probabilistic Models

Histological whole slide images (WSIs) can be usually compromised by artifacts, such as tissue folding and bubbles, which will increase the examination difficulty for both pathologists and Computer-Aided Diagnosis (CAD) systems. Existing approaches to restoring artifact images are confined to Generative Adversarial Networks (GANs), where the restoration process is formulated as an image-to-image transfer. Those methods are prone to suffer from mode collapse and unexpected mistransfer in the stain style, leading to unsatisfied and unrealistic restored images. Innovatively, we make the first attempt at a denoising diffusion probabilistic model for histological artifact restoration, namely ArtiFusion.Specifically, ArtiFusion formulates the artifact region restoration as a gradual denoising process, and its training relies solely on artifact-free images to simplify the training complexity.Furthermore, to capture local-global correlations in the regional artifact restoration, a novel Swin-Transformer denoising architecture is designed, along with a time token scheme. Our extensive evaluations demonstrate the effectiveness of ArtiFusion as a pre-processing method for histology analysis, which can successfully preserve the tissue structures and stain style in artifact-free regions during the restoration. Code is available at https://github.com/zhenqi-he/ArtiFusion.Comment: Accepted by MICCAI202

Graph Denoising Diffusion for Inverse Protein Folding

Inverse protein folding is challenging due to its inherent one-to-many mapping characteristic, where numerous possible amino acid sequences can fold into a single, identical protein backbone. This task involves not only identifying viable sequences but also representing the sheer diversity of potential solutions. However, existing discriminative models, such as transformer-based auto-regressive models, struggle to encapsulate the diverse range of plausible solutions. In contrast, diffusion probabilistic models, as an emerging genre of generative approaches, offer the potential to generate a diverse set of sequence candidates for determined protein backbones. We propose a novel graph denoising diffusion model for inverse protein folding, where a given protein backbone guides the diffusion process on the corresponding amino acid residue types. The model infers the joint distribution of amino acids conditioned on the nodes' physiochemical properties and local environment. Moreover, we utilize amino acid replacement matrices for the diffusion forward process, encoding the biologically-meaningful prior knowledge of amino acids from their spatial and sequential neighbors as well as themselves, which reduces the sampling space of the generative process. Our model achieves state-of-the-art performance over a set of popular baseline methods in sequence recovery and exhibits great potential in generating diverse protein sequences for a determined protein backbone structure

コウキ キンダイ ニ オケル キョウセイ ノ シャカイ ガクテキ コウサツ サイキセイ ノ シテン カラ

本稿では、社会学者A.ギデンズの近代化理論と構造化理論を援用し、近代化の視点から後期近代における「共生」の様相を考察する。まずは、ギデンズの近代化論が描いた近代化の特徴を論拠としつつ、「共生」の言説は近代化の産物であることを論じる。次に、前近代社会の特徴を考察し、前近代において「共生」が成立できない理由について論じる。そして、近代化とともに徹底されていく再帰性に注目し、「共生」と再帰性の関係性を考察する。その上で、ギデンズの構造化理論に基き、後期近代における「共生」的諸実践に求められる能動的な行為者について考察する。This paper uses the modernization theory and structuration theory of sociologist A. Giddens to consider the aspect of "Kyōsei" in the late modern period from the viewpoint of modernization. The first part argues that the discourse of "Kyōsei" is a product of modernization, based on the characteristics of modernization drawn by Giddens' theory of modernization. The second part considers the characteristics of pre-modern society and discusses the reasons why "Kyōsei" cannot be established in pre-modern times. Then, paying attention to the reflexivity that becomes thorough with modernization, the third part considers the relationship between "Kyōsei" and reflexivity. Then, based on Giddens's structuration theory, the fourth part considers the active agents required for the practices of "Kyōsei" in the late modern period.論