Distributed Active Partial Label Learning

Active learning(AL)trains a high-precision predictor model from small numbers of labeled data by iteratively annotating the most valuable data sample from an unlabeled data pool with a class label throughout the learning process.However,most current AL methods start with the premise that the labels queried at AL rounds must be free of ambiguity,which may be unrealistic in some real-world applications where only a set of candidate labels can be obtained for selected data.Besides,most of the existing AL algorithms only consider the case of centralized processing,which necessitates gathering together all the unlabeled data in one fusion center for selection.Considering that data are collected/stored at different nodes over a network in many real-world scenarios,distributed processing is chosen here.In this paper,the issue of distributed classification of partially labeled(PL)data obtained by a fully decentralized AL method is focused on,and a distributed active partial label learning(dAPLL)algorithm is proposed.Our proposed algorithm is composed of a fully decentralized sample selection strategy and a distributed partial label learning(PLL)algorithm.During the sample selection process,both the uncertainty and representativeness of the data are measured based on the global cluster centers obtained by a distributed clustering method,and the valuable samples are chosen in turn.Meanwhile,using the disambiguation-free strategy,a series of binary classification problems can be constructed,and the corresponding cost-sensitive classifiers can be cooperatively trained in a distributed manner.The experiment results conducted on several datasets demonstrate that the performance of the dAPLL algorithm is comparable to that of the corresponding centralized method and is superior to the existing active PLL(APLL)method in different parameter configurations.Besides,our proposed algorithm outperforms several current PLL methods using the random selection strategy,especially when only small amounts of data are selected to be assigned with the candidate labels.

Numerical computation of central crack growth in an active particle of electrodes influenced by multiple factors

Mechanical degradation, especially fractures in active particles in an electrode, is a major reason why the capacity of lithiumion batteries fades. This paper proposes a model that couples Li-ion diffusion, stress evolution, and damage mechanics to simulate the growth of central cracks in cathode particles（Li Mn_2 O_4） by an extended finite element method by considering the influence of multiple factors. The simulation shows that particles are likely to crack at a high discharge rate, when the particle radius is large, or when the initial central crack is longer. It also shows that the maximum principal tensile stress decreases and cracking becomes more difficult when the influence of crack surface diffusion is considered. The fracturing process occurs according to the following stages： no crack growth, stable crack growth, and unstable crack growth. Changing the charge/discharge strategy before unstable crack growth sets in is beneficial to prevent further capacity fading during electrochemical cycling.

Emergent Swarming States in Active Particles System with Opposite Anisotropic Interactions

From the organization of animal flocks to the emergence of swarming behaviors in bacterial suspension,populations of motile organisms at all scales display coherent collective motion.Recent studies showed that the anisotropic interaction between active particles plays a key role in the phase behaviors.Here we investigate the collective behaviors of based-active Janus particles that experience an anisotropic interaction of which the orientation is opposite to the direction of active force by using Langevin dynamics simulations in two dimensional space.Interestingly,the system shows emergence of collective swarming states upon increasing the total area fraction of particles,which is not observed in systems without anisotropic interaction or activity.The threshold for emergence of swarming states decreases as particle activity or interaction strength increases.We have also performed basic kinetic analysis to reproduce the essential features of the simulation results.Our results demonstrate that anisotropic interactions at the individual level are sufficient to set homogeneous active particles into stable directed motion.

Effective transport of passive particles induced by chiral-active particles in microchannel

Transport of passive particles induced by chiral-active particles in microchannel is investigated by using the overdamped Langevin dynamics simulation in a two-dimensional model system. Due to the chirality of active particles and special structure of microchannel, effective ratchet transport of passive particles is achieved. Effective transport of passive particles depends on the width of microchannel（d）, the density（ρ）, and the angular velocity（ω） of chiral-active particles.There exist optimal parameters for d and ω at which the transport efficiency for passive particles takes its maximal value.This investigation can help us understand the necessity of active motion for living systems to maintain a number of vital processes such as materials transport inside cells and the foraging dynamics of mobile organisms.

Unidirectional rotation of circles driven by chiral active particles

The dynamics of two-dimensional rigid circles filled with chiral active particles are investigated by employing the overdamped Langevin dynamics simulations. Unidirectional rotation of rigid circles is observed, and the rotational angular velocity（ω） relies mainly on the length（l）, the number（nB）, and tilt angle（γ） of boards, and the angular velocity（ω）and area fraction（ρ） of chiral active particles. There are optimum values for these parameters at which the average angular velocity of circle reaches its maximum. The center-of-mass mean square displacement for circles drops by about two orders of magnitude for large angular velocity ω of chiral active particles with oscillations in the short-time regime. Our work demonstrates that nanofabricated objects with suitable designs immersed in a bath of chiral active particles can extract and rectify energy in a unidirectional motion.

Collective motion of polar active particles on a sphere

Collective motion of active particles with polar alignment is investigated on a sphere.We discussed the factors that affect particle swarm motion and define an order parameter that can show the degree of particle swarm motion.In the model,we added a polar alignment strength,along with Gaussian curvature,affecting particles swarm motion.We find that when the force exceeds a certain limit,the order parameter will decrease with the increase of the force.Combined with our definition of order parameter and observation of the model,the reason is that particles begin to move side by side under the influence of polar forces.In addition,the effects of velocity,rotational diffusion coefficient,and packing fraction on particle swarm motion are discussed.It is found that the rotational diffusion coefficient and the packing fraction have a great influence on the clustering motion of particles,while the velocity has little influence on the clustering motion of particles.

Superfast and solvent-free core-shell assembly of sulfur/carbon active particles by hail-inspired nanostorm technology for high-energy-density Li-S batteries

The demand on low-carbon emission fabrication technologies for energy storage materials is increasing dramatically with the global interest on carbon neutrality.As a promising active material for metal-sulfur batteries,sulfur is of great interest due to its high-energy-density and abundance.However,there is a lack of industry-friendly and low-carbon fabrication strategies for high-performance sulfur-based active particles,which,however,is in critical need by their practical success.Herein,based on a hail-inspired sulfur nano-storm(HSN)technology developed in our lab,we report an energy-saving,solvent-free strategy for producing core-shell sulfur/carbon electrode particles(CNT@AC-S)in minutes.The fabrication of the CNT@AC-S electrode particles only involves low-cost sulfur blocks,commercial carbon nanotubes(CNT)and activated carbon(AC)micro-particles with high specific surface area.Based on the above core-shell CNT@AC-S particles,sulfur cathode with a high sulfur-loading of 9.2 mg cm^(-2) delivers a stable area capacity of 6.6 mAh cm^(-2) over 100 cycles.Furthermore,even for sulfur cathode with a super-high sulfur content(72 wt%over the whole electrode),it still delivers a high area capacity of 9 mAh cm^(-2) over50 cycles in a quasi-lean electrolyte condition.In a nutshell,this study brings a green and industryfriendly fabrication strategy for cost-effective production of rationally designed S-rich electrode particles.

Screening on the Pharmacodynemic Active Parts of Protecting Liver of Peristrope japonica (thunb.)Bremek

The pharmacodynamic active parts of protecting liver of Peristrope japonica (thunb.)Bremek were identified. Rat acute liver injury model was induced by D-galactosamine (D-GlaN). The active parts were identified on the whole extraction and 4 fractions. The results showed that the pharmacodynamic active parts of Peristrope japonica were the n-BuOH fraction.

OBSERVING THE ENTIRE GLOBE FOR THE GOOD OF THE MANKIND——China takes an Active Part in Activities of the“International Space Year”

The experience of the mankind in studying the planet of our own, is long and the progress is accelerated. From the numerous geographic adventures organized in the past thousand years came only the brief knowledge of the outline of the land and ocean; with the scientific explorations and topographic mapping activities done in the 300-plus years that followed, only about 30% of the land got mapped. But things have been changed greatly since the beginning of the century, when the air planes were put into use for mapping: up to 1950’s, the mapped areas had gone up to 70%; From 1957, a series of resource and environment satellites have been launched one after another,observing the globe, giving coverage of it and providing endlessly varieties of information about the seas and the lands day and night.

The Active Participation of ASIAA in the SMA Project

This is a progress report of a major project that Institute of Astronomy & Astrophysics is actively engaged. The two 6m sub millimeter telescopes are being built in Taiwan. The construction of the antennas, which has been contracted to Aeronautic Research Laboratory, has made good progress lately. The first reflector is completed. The mounts are also nearly finished. The antennas are expected to be completed and tested in late 1999. Our receiver lab has been built up from scratch. It is finishing the assembly of the first SMA receiver. It is also fabricating its first Nb AlO x Nb junction of 230 GHz. Our two telescopes are scheduled to join the two SAO telescopes presently at Mauna Kea in the spring of year 2000.

Anomalous boundary deformation induced by enclosed active particles

We simulate a two-dimensional model of a round soft boundary enclosed with self-propelled particles. Persistent motion drives these particles to accumulate near the boundary, thereby dramatically deforming the boundary shape through collisions. Quantitative analyses of the boundary shape and the particle distribution show that there are two typical regimes in the variation of the morphology with the increase of self-propulsion of particles. One is under small forces, characterized by the radially inhomogeneous distribution of particles and the suppression of local fluctuations of the almost round boundary, and the other is under large forces, featured by the angularly inhomogeneous distribution of particles and the global shape deformation of the boundary. These two features are strongly cooperative. We also find different mechanisms in the particle relocation at low and high particle concentrations.

Collective motion of active particles in environmental noise

We study the collective motion of active particles in environmental noise, where the environmental noise is caused by noise particles randomly diffusing in two-dimensional space. We show that active particles in a noisy environment can self organize into three typical phases： polar liquid, band, and disordered gas states. In our model, the transition between band and disordered gas states is discontinuous. Giant number fluctuation is observed in the polar liquid phase. We also compare our results with the Vicsek model and show that the interaction with noise particles can stabilize the band state to very low noise condition. This band structure could recruit most of the active particles in the system, which greatly enhances the coherence of the system. Our findings of complex collective behaviors in environmental noise help us to understand how individuals modify their self-organization by environmental factors, which may further contribute to improving the design of collective migration and navigation strategies.

An Empirical Study on Promoting Students’ Active Participation under“Task-based Teaching”in Adult ESL Classrooms

This paper focuses on a beginner adult ESL classroom aiming to enhance their participation under the guidance of“taskbased teaching”method. By incorporating three strategies of priming students to elicit their prior knowledge on certain topic, designing a sequence of tasks to scaffold students for the final produce and modelling with lower level students to ensure their under? standing of task instructions, the activeness could see a significant increase.

Spontaneous unidirectional rotation of a symmetric gear driven by spherical active particles

Time reversal asymmetry and spatial anisotropy are considered two prerequisites for Brownian ratchet.An intriguing realization can be achieved by placing an asymmetric gear in the suspension of motile rod-like bacteria.Usually,alignment interactions caused by anisotropic collisions or hydrodynamics would boost the ratchet effect.Here,we are concerned with a perfectly isotropic system,i.e.,symmetric gear immersed in a bath of spherical active Brownian particles.We find that,under certain conditions,kinetic symmetry-breaking arises spontaneously,i.e.,the symmetric gear keeps rotating in one direction.Unexpectedly,such ratchet phenomenon does not rely on the direct many-particle interactions and moreover the introduction of alignment interaction would counterintuitively prevent it from happening!Further investigation reveals that such spontaneous symmetry-breaking phenomenon shares similarities with the equilibrium phase transition of the Ising model.Our results provide new insights and enhance our understanding of the fundamental aspects of active ratchet phenomena.

A Two-Layer Active Power Optimization and Coordinated Control for Regional Power Grid Partitioning to Promote Distributed Renewable Energy Consumption

With the large-scale development and utilization of renewable energy,industrial flexible loads,as a kind of loadside resource with strong regulation ability,provide new opportunities for the research on renewable energy consumption problem in power systems.This paper proposes a two-layer active power optimization model based on industrial flexible loads for power grid partitioning,aiming at improving the line over-limit problem caused by renewable energy consumption in power grids with high proportion of renewable energy,and achieving the safe,stable and economical operation of power grids.Firstly,according to the evaluation index of renewable energy consumption characteristics of line active power,the power grid is divided into several partitions,and the interzone tie lines are taken as the optimization objects.Then,on the basis of partitioning,a two-layer active power optimization model considering the power constraints of industrial flexible loads is established.The upper-layer model optimizes the planned power of the inter-zone tie lines under the constraint of the minimum peak-valley difference within a day;the lower-layer model optimizes the regional source-load dispatching plan of each resource in each partition under the constraint of theminimumoperation cost of the partition,so as to reduce the line overlimit phenomenon caused by renewable energy consumption and save the electricity cost of industrial flexible loads.Finally,through simulation experiments,it is verified that the proposed model can effectively mobilize industrial flexible loads to participate in power grid operation and improve the economic stability of power grid.

“ACTIVE”英语学科育人模式构建与应用

本研究以“立德树人”为核心理念,构建“ACTIVE”英语学科育人模式。该模式通过六个关键维度--学科育人(AIM)、文化浸润(Culture)、思维可见(Thinking)、技术融合(Integration)、美德根植(Virtue)和情感共鸣(Empathy)--全面激发学生英语学习的热情,培养他们的语言能力,同时注重道德品质的熏陶和文化素养的提升,促进英语学科素养落地。本研究不仅为英语教学实践提供了新的视角,也为其他学科育人模式的构建提供了有益的参考和借鉴。

Liquid crystal-integrated metasurfaces for an active photonic platform

Metasurfaces have opened the door to next-generation optical devices due to their ability to dramatically modulate electromagnetic waves at will using periodically arranged nanostructures.However,metasurfaces typically have static optical responses with fixed geometries of nanostructures,which poses challenges for implementing transition to technology by replacing conventional optical components.To solve this problem,liquid crystals(LCs)have been actively employed for designing tunable metasurfaces using their adjustable birefringent in real time.Here,we review recent studies on LCpowered tunable metasurfaces,which are categorized as wavefront tuning and spectral tuning.Compared to numerous reviews on tunable metasurfaces,this review intensively explores recent development of LC-integrated metasurfaces.At the end of this review,we briefly introduce the latest research trends on LC-powered metasurfaces and suggest further directions for improving LCs.We hope that this review will accelerate the development of new and innovative LC-powered devices.

Variation in the permafrost active layer over the Tibetan Plateau during 1980–2020

The active layer,acting as an intermediary of water and heat exchange between permafrost and atmosphere,greatly influences biogeochemical cycles in permafrost areas and is notably sensitive to climate fluctuations.Utilizing the Chinese Meteorological Forcing Dataset to drive the Community Land Model,version 5.0,this study simulates the spatial and temporal characteristics of active layer thickness(ALT)on the Tibetan Plateau(TP)from 1980 to 2020.Results show that the ALT,primarily observed in the central and western parts of the TP where there are insufficient station observations,exhibits significant interdecadal changes after 2000.The average thickness on the TP decreases from 2.54 m during 1980–1999 to 2.28 m during 2000–2020.This change is mainly observed in the western permafrost region,displaying a sharp regional inconsistency compared to the eastern region.A persistent increasing trend of ALT is found in the eastern permafrost region,rather than an interdecadal change.The aforementioned changes in ALT are closely tied to the variations in the surrounding atmospheric environment,particularly air temperature.Additionally,the area of the active layer on the TP displays a profound interdecadal change around 2000,arising from the permafrost thawing and forming.It consistently decreases before 2000 but barely changes after 2000.The regional variation in the permafrost active layer over the TP revealed in this study indicates a complex response of the contemporary climate under global warming.

An active high-static-low-dynamic-stiffness vibration isolator with adjustable buckling beams:theory and experiment

High-static-low-dynamic-stiffness(HSLDS)vibration isolators with buckling beams have been widely used to isolate external vibrations.An active adjustable device composed of proportion integration(PI)active controllers and piezoelectric actuators is proposed for improving the negative stiffness stroke of buckling beams.A nonlinear output frequency response function is used to analyze the effect of the vibration reduction.The prototype of the active HSLDS device is built,and the verification experiment is conducted.The results show that compared with the traditional HSLDS vibration isolator,the active HSLDS device can broaden the isolation frequency bandwidth,and effectively reduce the resonant amplitude by adjusting the active control parameters.The maximum vibration reduction rate of the active HSLDS vibration isolator can attain 89.9%,and the resonant frequency can be reduced from 31.08 Hz to 13.28 Hz.Therefore,this paper devotes to providing a new design scheme for enhanced HSLDS vibration isolators.

Optimal Location and Sizing of Distributed Generator via Improved Multi-Objective Particle Swarm Optimization in Active Distribution Network Considering Multi-Resource

In the framework of vigorous promotion of low-carbon power system growth as well as economic globalization,multi-resource penetration in active distribution networks has been advancing fiercely.In particular,distributed generation(DG)based on renewable energy is critical for active distribution network operation enhancement.To comprehensively analyze the accessing impact of DG in distribution networks from various parts,this paper establishes an optimal DG location and sizing planning model based on active power losses,voltage profile,pollution emissions,and the economics of DG costs as well as meteorological conditions.Subsequently,multiobjective particle swarm optimization(MOPSO)is applied to obtain the optimal Pareto front.Besides,for the sake of avoiding the influence of the subjective setting of the weight coefficient,the decisionmethod based on amodified ideal point is applied to execute a Pareto front decision.Finally,simulation tests based on IEEE33 and IEEE69 nodes are designed.The experimental results show thatMOPSO can achieve wider and more uniformPareto front distribution.In the IEEE33 node test system,power loss,and voltage deviation decreased by 52.23%,and 38.89%,respectively,while taking the economy into account.In the IEEE69 test system,the three indexes decreased by 19.67%,and 58.96%,respectively.