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Follow the perturbed approximate leader for solving semi-bandit combinatorial optimization

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Frontiers of Computer Science 2021年第5期15卷 161-172页

作者： Feidiao YANG Wei CHEN jialin zhang Xiaoming SUN Institute of Computing Technology Chinese Academy of SciencesBejing 100190China University of Chinese Academy of Sciences Beijing 100190China Microsoft Research Asia Beijing 100080China

Combinatorial optimization in the face of uncertainty is a challenge in both operational research and machine *** this paper,we consider a special and important class called the adversarial online combinatorial optimization with semi-bandit feedback,in which a player makes combinatorial decisions and gets the corresponding feedback *** existing algorithms focus on the regret guarantee or assume there exists an efficient offline oracle,it is still a challenge to solve this problem efficiently if the offline counterpart is *** this paper,we propose a variant of the Follow-the-Perturbed-Leader(FPL)algorithm to solve this *** the existing FPL approach,our method employs an approximation algorithm as an offline oracle and perturbs the collected data by adding nonnegative random *** ap-proach is simple and computationally ***,it can guarantee a sublinear(1+ε)-scaled regret of order O(T^(2/3))for any smallε>0 for an important class of combinatorial optimization problems that admit an FPTAS(fully polynomial time approximation scheme),in which T is the number of rounds of the learning *** addition to the theoretical analysis,we also conduct a series of experiments to demonstrate the performance of our algorithm.

关键词： online learning online combinatorial optimization semi-bandit follow-the-perturbed-leader

Impacts of Surface Exchange Coefficients on Simulations of Super Typhoon Megi(2010)Using a Coupled Ocean-Atmosphere-Wave Model

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Journal of Ocean University of China 2023年第3期22卷 587-600页

作者： zhang Wenqing zhang jialin GUAN Changlong SUN Jian College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266100China Physical Oceanography Laboratory Ocean University of ChinaQingdao 266100China Qingdao Municipal Marine Development and Promotion Center Qingdao 266071China

In this study,the effects of surface exchange coefficients on simulations of Super Typhoon Megi(2010)are investigated using a fully coupled ocean-atmosphere-wave *** experiments are conducted using different parameterization schemes for the drag(C_(D))and enthalpy exchange(C_(K))*** the selected case,considering only the leveling-off of C_(D)at high wind speeds does not effectively improve the simulated typhoon track,intensity,or *** found that increasing C_(K)monotonically with wind speed(Komori et al.,2018)yields stronger winds and deeper pressures by enhancing latent and sensible heat fluxes,but typhoon intensity remains *** propose a new higher C_(K)than that from Komori et al.(2018)based on the theory of Emanuel(1995).This approach produces a greater modeled typhoon intensity that is in good agreement with the best track data and effectively improves the track error for the *** accuracy for modeled typhoon intensity is achieved with the new coefficient because C_(K)/C_(D)reaches the threshold of about 0.75 predicted by Emanuel(1995).The new proposed C_(K)also results in a reasonably accurate modeled sea surface ***,typhoon size and surface wave height are *** finding implies that more numerical tests for tropical cyclones of different nature(such as strong,weak,dissipating,rapidly intensifying,or weakening tropical cyclones)should be studied,and more physical processes should be explored in future coupled models.

关键词： typhoon drag coefficient enthalpy exchange coefficient coupled ocean-atmosphere-wave model

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A Novel On-Site-Real-Time Method for Identifying Characteristic Parameters Using Ultrasonic Echo Groups and Neural Network

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 215-228页

作者： Shuyong Duan jialin zhang Heng Ouyang Xu Han Guirong Liu State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of TechnologyTianjin 300401China Department of Aerospace Engineering and Engineering Mechanics University of CincinnatiCincinnati 45221USA

On-site and real-time non-destructive measurement of elastic constants for materials of a component in a in-service structure is a challenge due to structural complexities,such as ambiguous boundary,variable thickness,nonuniform material *** work develops for the first time a method that uses ultrasound echo groups and artificial neural network(ANN)for reliable on-site real-time identification of material *** use of echo groups allows the use of lower frequencies,and hence more accommodative to structural *** train the ANNs,a numerical model is established that is capable of computing the waveform of ultrasonic echo groups for any given set of material properties of a given *** waveform of an ultrasonic echo groups at an interest location on the surface the structure with material parameters varying in a predefined range are then computed using the numerical *** results in a set of dataset for training the ANN *** the ANN is trained,the material parameters can be identified simultaneously using the actual measured echo waveform as input to the *** tests have been conducted both numerically and experimentally to evaluate the effectiveness and accuracy of the currently proposed *** results show that the maximum identification error of numerical example is less than 2%,and the maximum identification error of experimental test is less than 7%.Compared with currently prevailing methods and equipment,the proposefy the density and thickness,in addition to the elastic ***,the reliability and accuracy of inverse prediction is significantly ***,it has broad applications and enables real-time field measurements,which has not been fulfilled by any other available methods or equipment.

关键词： Parameter identification Ultrasonic echo group High-precision modeling Artificial neural network NDT

Cumulative activation in social networks

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Science China(Information Sciences) 2019年第5期62卷 108-128页

作者： Xiaohan SHAN Wei CHEN Qiang LI Xiaoming SUN jialin zhang Department of Computer Science and Technology Tsinghua University Microsoft CAS Key Lab of Network Data Science and Technology Institute of Computing TechnologyChinese Academy of Sciences University of Chinese Academy of Sciences

Most studies on influence maximization focus on one-shot propagation, i.e., the influence is propagated from seed users only once following a probabilistic diffusion model and users’ activation are determined via single cascade. In reality it is often the case that a user needs to be cumulatively impacted by receiving enough pieces of information propagated to her before she makes the final purchase decision. In this paper we model such cumulative activation as the following process: first multiple pieces of information are propagated independently in the social network following the classical independent cascade model, then the user will be activated(and adopt the product) if the cumulative pieces of information she received reaches her cumulative activation threshold. Two optimization problems are investigated under this framework: seed minimization with cumulative activation(SM-CA), which asks how to select a seed set with minimum size such that the number of cumulatively active nodes reaches a given requirement η; influence maximization with cumulative activation(IM-CA), which asks how to choose a seed set with fixed budget to maximize the number of cumulatively active nodes. For SM-CA problem, we design a greedy algorithm that yields a bicriteria O(ln n)-approximation when η = n, where n is the number of nodes in the network. For both SM-CA problem with η < n and IM-CA problem, we prove strong inapproximability results. Despite the hardness results, we propose two efficient heuristic algorithms for SM-CA and IM-CA respectively based on the reverse reachable set approach. Experimental results on different real-world social networks show that our algorithms significantly outperform baseline algorithms.

关键词： social networks cumulative activation influence maximization seed minimization

Polyoxometalate-based electrolyte materials in redox flow batteries:Current trends and emerging opportunities

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Materials Reports(Energy) 2022年第2期2卷 39-57页

作者： Yiyang Liu jialin zhang Shanfu Lu Yan Xiang Beijing Key Laboratory of Bio-inspired Energy Materials and Devices School of Space and EnvironmentBeihang UniversityBeijing100191PR China

Redox flow batteries have received wide attention for electrochemical energy conversion and storage devices due to their specific advantage of uncoupled power and energy devices,and therefore potentially to reduce the capital costs of energy *** structural features of polyoxometalates exhibit unique advantages in redox flow batteries,such as,stable chemical properties,multi-electron reaction,good redox reversibility,low permeability,etc,which furnishes a novel perspective for settling various problems of redox flow *** was a comprehensive and critical review of this type of batteries,focusing mainly on the chemistry of polyoxometalate electrolyte materials and introducing a systematic ***,challenges and perspectives of polyoxometalate electrolyte materials and polyoxometalate redox flow batteries are discussed.

关键词： Redox flow battery Electrolyte materials Polyoxometalate Electrolyte design

High-entropy L1_(2)-Pt(FeCoNiCuZn)_(3) intermetallics for ultrastable oxygen reduction reaction

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Journal of Energy Chemistry 2023年第11期86卷 158-166,I0004页

作者： Qian zhang Tao Shen Min Song Shuang Wang jialin zhang Xiao Huang Shanfu Lu Deli Wang Key Laboratory of Material Chemistry for Energy Conversion and Storage(Huazhong University of Science and Technology) Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina Beijing Key Laboratory of Bio-inspired Energy Materials and Devices School of Space and EnvironmentBeihang UniversityBeijing 100191China

Enhancing the stability of Pt-based electrocatalysts for the sluggish cathodic oxygen reduction reaction(ORR)is critical for proton exchange membrane fuel cells(PEMFCs).Herein,high-entropy intermetallic(HEI)L1_(2)-Pt(FeCoNiCuZn)3is designed for durable ORR *** from the unique HEI structure and the enhanced intermetallic phase stability,Pt(FeCoNiCuZn)3/C nanoparticles demonstrate significantly improved stability over Pt/C and PtCu_(3)/C *** Pt(FeCoNiCuZn)3/C exhibits a negligible decay of the half-wave potential during 30,000 potential cycles from 0.6 to 1.0 V,whereas Pt/C and PtCu_(3)/C are negatively shifted by 46 and 36 m V,*** after 10,000 cycles at potential up to 1.5 V,the mass activity of Pt(FeCoNiCuZn)3/C still shows~70%*** evidenced by the structural characterizations,the HEI structure of Pt(FeCoNiCuZn)3/C is well maintained,while PtCu_(3)/C nanoparticles undergo severe Cu leaching and particle *** addition,when assembled Pt(FeCoNiCuZn)3/C as the cathode in high-temperature PEMFC of 160℃,the H_(2)-O_(2)fuel cell delivers almost no degradation even after operating for 150 h,demonstrating the potential for fuel cell *** work provides a facile design strategy for the development of high-performance ultrastable electrocatalysts.

关键词： High-entropy intermetallics Pt-based electrocatalysts Oxygen reduction reaction High stability

Analysis on the deployment of mining research supported by the grant program of Deep Resources Exploration and Mining

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煤田地质与勘探 2021年第3期49卷 1-7页

作者： FAN Jun zhang jialin QIN Yuan WANG Hao GAO Yanan PEI Yongzhi The Administrative Centre for China’s Agenda 21 Beijing 100038China School of Mechanics and Civil Engi-neering China University of Mining and&TechnologyXuzhou 221116China

The Deep Resources Exploration and Mining(DREAM)grant program,within the framework of The National Key Research and Development Program grants,is a pillar to implement China’s science and technology strategy in the area of deep resources *** tackle the insufficient of theories and technologies for the 1000-meter-deep mining,a section of mining,covering the research of basic theories,general technologies and application demonstration,was arranged in the layout of DREAM under the principle of"whole chain design,integrated implementation".In the aspect of basic research,DREAM mainly focused on the deep rock mechanics and mining theory,such as the in-situ mechanical behavior of deep rock,deep high stress induction and energy regulation *** the general and key technologies,DREAM supported the research on the mine construction and hoisting,excavation,rock breaking,mining methods and mining safety according to the characteristics of coal and metal *** the demonstration application,taking green,safe and efficient as the starting point,DREAM aimed at the green,safe and high efficiency mining,and the demonstration and leading role projects such as the low-waste and high-efficiency back fill *** 2016,10 R&D projects have been funded,and 122 institutional participants with a total budget of RMB 235 million from the central government and RMB 480 million from enterprises as well as local governments have been *** is expected that the mining section of DREAM would contribute to establishing the theory and technology system in the area of deep mining and promoting the ability of deep resource exploitation in China.

关键词： resource of deep earth mining theory general technology application demonstration

Associations between parental support for physical activity and moderate-to-vigorous physical activity among Chinese school children： A cross-sectional study

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Journal of Sport and Health Science 2017年第4期6卷 410-415页

作者： Yang Liu Yajun zhang Sitong Chen jialin zhang Zongchen Guo Peijie Chen School of Physical Education and Sport Training Shanghai University of Sport Shanghai 200438 China Shanghai Research Center for Physical Fitness and Health of Children andAdoleseents Shanghai University of Sport Shanghai 200438 China rSchool of Physical Education Shaoxing University Shaoxing 312000 China Educational Management Information Center Ministry of Education Beijing 100816 China School of Kinesiology Shanghai University of Sport Shanghai 200458 China

Purpose: The objective of this study was to examine the associations between parental support for physical activity(PA) and levels of moderate-to-vigorous physical activity(MVPA) among Chinese school ***: Study participants were 81,857 school-aged children(aged 9–17 years; mean age = 13 years; 49.0% boys) and their parents or guardians who took part in the 2016 Physical Activity and Fitness in China—The Youth Study project. The independent variables included various forms of parental support for PA ascertained through a survey completed by parents or guardians. The dependent variable was the children's average MVPA in minutes per day by self-report. Structure equation modeling was used to examine the associations between parental support for PA and children's MVPA ***: The overall mean for MVPA participation time for the child participants was 48.82 ± 28.71 min/day. Significant associations between various forms of parental support and MVPA among children were found. Parental encouragement, accompanying, financial support, involvement,and role modeling for PA were positively associated with a high level of student MVPA participation. Parental PA knowledge-sharing was not associated with MVPA. The patterns of the associations were similar across sex, residence locale(i.e., urban and rural), and school grades(primary,junior middle, and junior high schools).Conclusion: Findings from this study suggest that, among Chinese school children, parental support for PA is important in promoting and facilitating children's participation in MVPA.

关键词： 2hildren and youth sports Chinese family Exercise Parenting

Mid-infrared plasmonic silicon quantum dot/HgCdTe photodetector with ultrahigh specific detectivity

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Science China(Information Sciences) 2023年第4期66卷 286-292页

作者： Yueying CUI Zhouyu TONG Xinlei zhang Wenhui WANG Weiwei ZHAO Yuanfang YU Xiaodong PI jialin zhang Zhenhua NI School of Physics and Key Laboratory of MEMS of Ministry of Education Southeast University State Key Laboratory of Silicon Materials School of Materials Science and Engineering Zhejiang University

Highly sensitive photodetectors operating at mid-infrared(MIR) wavelengths are urgently required for the applications of astronomy, optical communication, security monitoring, and so forth. However,further promoting the sensitivity in conventional MIR devices for a higher detectivity is challenging. Among the potential strategies, integrating localized surface plasmon resonance with MIR semiconductors is a promising approach to developing high-performance optoelectronics. Here we demonstrate a high-sensitivity boron(B)-doped silicon quantum dot(Si-QD)/HgCdTe(MCT) MIR photodetector. Because of plasmon-induced hot-hole tunneling and enhanced light absorption, the hybrid photodetector exhibits a high specific detectivity of ～1.6×109cm·Hz1/2·W-1(Jones) and a high-speed response(～224 ns for the rise time and ～580 ns for the fall time) at room temperature. Furthermore, the device achieves high-performance spectral blackbody detection with a peak detectivity of up to 1.6×1011Jones at ～5.8 μm under a cryogenic environment of 77 K, higher than that of bare MCT. This prominent enhancement can be attributed to the further suppression of hot-hole cooling due to a reduced phonon population at low temperatures, which facilitates more efficient hot-carrier extraction and contributes to ultrahigh sensitivity. The plasmonic material-integrated MCT architecture can pave the way for developing high-performance MIR photodetection.

关键词： doped silicon quantum dots HgCdTe localized surface plasmon resonance hot-hole tunneling mid-infrared photodetector