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Integrated photonic fractional convolution accelerator

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Photonics Research 2024年第8期12卷 1828-1839页

作者： kevin ZELAYA MOHAMMEd-ALI MIRI department of Physics Queens College of the City University of New YorkQueensNew York 11367USA Physics Program The Graduate Center of the City University of New YorkNew YorkNew York 10016USA

An integrated photonic circuit architecture to perform a modified-convolution operation based on the discrete fractional Fourier transform(dFrFT) is introduced. This is accomplished by utilizing two nonuniformly coupled waveguide lattices with equally spaced eigenmode spectra, the lengths of which are chosen so that the dFrFT and its inverse operations are achieved. A programmable modulator array is interlaced so that the required fractional convolution operation is performed. Numerical simulations demonstrate that the proposed architecture can effectively perform smoothing and edge detection tasks even for noisy input signals, which is further verified by electromagnetic wave simulations. Notably, mild lattice defects do not jeopardize the architecture performance, showing its resilience to manufacturing errors.

关键词： fractional convolution utilizing

Neuron-to-astrocyte proteostatic stress signaling in response to tau pathology

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Neural Regeneration Research 2024年第3期19卷 505-506页

作者： kevin Llewelyn Batenburg Wiep Scheper Amsterdam UMC location Vrije Universiteit Amsterdam Department of Human GeneticsAmsterdam Neuroscience-NeurodegenerationAmsterdamThe Netherlands department of Functional Genomics Center for Neurogenomics and Cognitive ResearchVrije Universiteit AmsterdamAmsterdam Neuroscience-NeurodegenerationAmsterdamThe Netherlands

Maintenance of protein homeostasis or“proteostasis”is essential for the functioning and viability of *** is in particular the case for cells like neurons that cannot self-renew and acquire unique functional properties during their *** proteostatic stress responses are in place to protect cells from damage in case of proteostatic *** integrated stress response(ISR)is one of the key proteostatic stress responses in the cell(Costa-Mattioli and Walter,2020).The ISR is the downstream convergence point for the four stress-induced eIF2αkinases(EIF2AK1-4)that control stress-regulated protein translation via phosphorylation of the translation factor eIF2α.ISR activation results in a transient reduction of global translation while it concomitantly enhances the translation of specific mRNAs,including that encoding the activating transcription factor 4(ATF4).Together,the translational control mediated by the ISR results in a temporary reduction of the overall protein load and the selectively increased expression of proteins that contribute to restoration of the proteostatic balance.

关键词： translation stress Together

High temperature deformation and recrystallization behavior of magnesium bicrystals with 90°<1010>and 90°<1120>tilt grain boundaries

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Journal of Magnesium and Alloys 2024年第2期12卷 625-638页

作者： kevin Bissa Talal Al-Samman dmitri A.Molodov Institute of Physical Metallurgy and Materials Physics RWTH Aachen University52056 AachenGermany International Research Organization for Advanced Science and Technology(IROAST) Kumamoto UniversityKumamoto 860-8555Japan

The deformation mechanisms and dynamic recrystallization(dRX)behavior of specifically grown bicrystals with a symmetric 90°and 90°tilt grain boundary,respectively,were investigated under deformation in plane strain compression at 200℃and 400℃.The microstructures were analyzed by panoramic optical microscopy and large-area electron backscatter diffraction(EBSd)orientation *** analysis employed a meticulous approach utilizing hundreds of individual,small EBSd maps with a small step size that were stitched together to provide comprehensive access to orientation and misorientation data on a macroscopic *** slip primarily governed the early stages of deformation at the two temperatures,and the resulting shear induced lattice rotation around the transverse direction(Td)of the *** existence of the grain boundary gave rise to dislocation pile-up in its vicinity,leading to much larger Td-lattice rotations within the boundary region compared to the *** increasing temperature,the deformation was generally more uniform towards the bulk due to enhanced dislocation mobility and more uniform stress *** recrystallization at 200℃was initiated in{1011}-compression twins at strains of 40%and *** 400℃,dRX consumed the entire grain boundary region and gradually replaced the deformed microstructure with progressing *** recrystallized grains displayed characteristic orientations,such that their c-axes were perpendicular to the Td and additionally scattered between 0°and 60°from the loading *** recrystallized grains displayed mutual rotations of up to 30°around the c-axes of the initial grains,forming a discernible basal fiber texture component,prominently visible in the{1120}pole *** is noteworthy that the deformation and dRX behaviors of the two analyzed bicrystals exhibited marginal variations in response to strain and deformation temperature.

关键词： Elevated deformation temperatures Plain strain compression Magnesium bicrystals Panorama EBSd dynamic Recrystallization

Orthogonal polynomial expansions for the valuation ofoptions under the stochastic volatility models with stochastic correlation

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Journal of Management Science and Engineering 2024年第2期9卷 239-253页

作者： kevin Z.Tong department of Mathematics and Statistics University of Ottawa585 King EdwardOttawaOntarioK1N 6N5Canada

This work provides a new method for pricing options under the generalized stochastic volatility models with Jacobi stochastic *** method is based on the observation that the generalized models belong to the class of polynomial diffusions and therefore the option prices can be efficiently computed via orthogonal polynomial *** take the Heston and Schöbel-Zhu models with stochastic correlation as two specific examples and are able to derive the analytical formulas for the option *** also illustrate the accuracy of the proposed method through a number of numerical experiments.

关键词： Orthogonal polynomial expansions Polynomial diffusions Stochastic correlation Jacobi process Stochastic volatility

Neurolithography:Lithography as an enabling technology in neurology and neuroscience

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Medicine in Novel Technology and devices 2024年第2期22卷 15-18页

作者： kevin Zhai department of Medical Education Weill Cornell Medicine-QatarP.O.Box 24144DohaQatar

Modern lithography,which enables the fabrication of complex structures in biomedical devices with exceptional precision,is a potentially transformative force in the neural *** such as photolithography,electron beam lithography,and soft lithography have been utilized to produce devices that guide neuronal growth and differentiation and measure electrophysiological signals at the single-cell *** the clinical sphere,lithography plays a role in the manufacturing of devices for deep brain stimulation,brain-computer interface,and ***,we briefly review the applications of lithography in basic and translational neuroscience and clinical neurology,with an eye toward future advancement.

关键词： Lithography Neurolithography Semiconductors Microfluidics Neural devices

Socioeconomic performance of in-between open spaces in a post-socialist city of Tirana,Albania

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Frontiers of Architectural Research 2024年第4期13卷 858-875页

作者： Anna Yunitsyna Ernest Shtepani kevin Hasa department of Architecture University Metropolitan TiranaTiranaAlbania department of Architecture Epoka UniversityTiranaAlbania

The urban development of Tirana during the last few years is characterized by significant expansion,population growth and intensive residential *** post-socialist city became much denser,more diverse in terms of building types,taller,and relatively lacking in public *** study is focused on the evaluation of in-between open public spaces,which are specific for different urban *** spatial configuration of in-between spaces is analyzed in relation to the level of social interaction and the presence of economic *** neighborhoods,which belong to socialist and post-socialist tower,slab,and courtyard building typologies,are selected as case *** methodology includes Space Syntax analysis,site surveys,and observations aiming to comprehend the socioeconomic performance and spatial organization of the *** overlap of the activity pattern,human behavior mapping,syntactic measurements,and site survey allows understanding the performance of different types of open spaces and to find the in-between space that facilitates the development of social and economic activities.

关键词： In-between space Building typology Space syntax Social activity Socioeconomic performance

An Efficient Smoothing and Thresholding Image Segmentation Framework with Weighted Anisotropic-Isotropic Total Variation

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1369-1405页

作者： kevin Bui Yifei Lou Fredrick Park Jack Xin department of Mathematics University of CaliforniaIrvineIrvineCA 92697-3875USA department of Mathematics University of North CarolinaChapel HillChapel HillNC 27599.USA department of Mathematics and Computer Science Whittier CollegeWhittierCA 90602USA

In this paper,we design an efficient,multi-stage image segmentation framework that incorporates a weighted difference of anisotropic and isotropic total variation(AITV).The segmentation framework generally consists of two stages:smoothing and thresholding,thus referred to as smoothing-and-thresholding(SaT).In the first stage,a smoothed image is obtained by an AITV-regularized Mumford-Shah(MS)model,which can be solved efficiently by the alternating direction method of multipliers(AdMMs)with a closed-form solution of a proximal operator of the l_(1)-αl_(2) *** convergence of the AdMM algorithm is *** the second stage,we threshold the smoothed image by K-means clustering to obtain the final segmentation *** experiments demonstrate that the proposed segmentation framework is versatile for both grayscale and color images,effcient in producing high-quality segmentation results within a few seconds,and robust to input images that are corrupted with noise,blur,or *** compare the AITV method with its original convex TV and nonconvex TVP(Od quantitative advantages of our proposed method.

关键词： Image segmentation Non-convex optimization Mumford-Shah(MS)model Alternating direction method of multipliers(AdMMs) Proximal operator

depressive semantic awareness from vlog facial and vocal streams via spatio-temporal transformer

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digital Communications and Networks 2024年第3期10卷 577-585页

作者： Yongfeng Tao Minqiang Yang Yushan Wu kevin Lee Adrienne Kline Bin Hu School of Information Science and Engineering Lanzhou UniversityLanzhouChina The School of Accounting Auditing and TaxationBusiness SchoolUNSW SydneyAustralia department of Preventive Medicine Northwestern UniversityChicagoILUnited States

With the rapid growth of information transmission via the Internet,efforts have been made to reduce network load to promote *** such application is semantic computing,which can extract and process semantic *** media has enabled users to share their current emotions,opinions,and life events through their mobile ***,people suffering from mental health problems are more willing to share their feelings on social ***,it is necessary to extract semantic information from social media(vlog data)to identify abnormal emotional states to facilitate early identification and *** studies do not consider spatio-temporal information when fusing multimodal information to identify abnormal emotional states such as *** solve this problem,this paper proposes a spatio-temporal squeeze transformer method for the extraction of semantic features of ***,a module with spatio-temporal data is embedded into the transformer encoder,which is utilized to obtain a representation of spatio-temporal ***,a classifier with a voting mechanism is designed to encourage the model to classify depression and non-depression *** are conducted on the d-Vlog *** results show that the method is effective,and the accuracy rate can reach 70.70%.This work provides scaffolding for future work in the detection of affect recognition in semantic communication based on social media vlog data.

关键词： Emotional computing Semantic awareness depression recognition Vlog data

Model Change Active Learning in Graph-Based Semi-supervised Learning

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1270-1298页

作者： kevin S.Miller Andrea L.Bertozzi department of Mathematics University of CaliforniaLos Angeles520 Portola PlazaLos AngelesCA 90095USA

Active learning in semi-supervised classification involves introducing additional labels for unlabelled data to improve the accuracy of the underlying classifier.A challenge is to identify which points to label to best improve performance while limiting the number of new labels."Model Change"active learning quantifies the resulting change incurred in the classifier by introducing the additional label(s).We pair this idea with graph-based semi-supervised learning(SSL)methods,that use the spectrum of the graph Laplacian matrix,which can be truncated to avoid prohibitively large computational and storage *** consider a family of convex loss functions for which the acquisition function can be efficiently approximated using the Laplace approximation of the posterior *** show a variety of multiclass examples that illustrate improved performance over prior state-of-art.

关键词： Active learning Graph-based methods Semi-supervised learning(SSL) Graph Laplacian