检索结果-南通市图书馆

DecMamba:Mamba Utilizing Series Decomposition for Multivariate Time Series Forecasting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2025年第1期82卷 1049-1068页

作者： Jianxin Feng Jianhao Zhang Ge Cao zhiguo liu Yuanming Ding Communication and Network Key Laboratory Dalian UniversityDalian116622China

Multivariate time series forecasting iswidely used in traffic planning,weather forecasting,and energy *** decomposition algorithms can help models better understand the underlying patterns of the original series to improve the forecasting accuracy of multivariate time ***,the decomposition kernel of previous decomposition-based models is fixed,and these models have not considered the differences in frequency fluctuations between *** problems make it difficult to analyze the intricate temporal variations of real-world time *** this paper,we propose a series decomposition-based Mamba model,DecMamba,to obtain the intricate temporal dependencies and the dependencies among different variables of multivariate time series.A variable-level adaptive kernel combination search module is designed to interact with information on different trends and periods between *** backbone structures are proposed to emphasize the differences in frequency fluctuations of seasonal and trend *** with superior performance is used instead of a Transformer in backbone structures to capture the dependencies among different variables.A new embedding block is designed to capture the temporal features better,especially for the high-frequency seasonal component whose semantic information is difficult to acquire.A gating mechanism is introduced to the decoder in the seasonal backbone to improve the prediction accuracy.A comparison with ten state-of-the-art models on seven real-world datasets demonstrates that DecMamba can better model the temporal dependencies and the dependencies among different variables,guaranteeing better prediction performance for multivariate time series.

关键词： Data prediction time series Mamba series decomposition

A q-operational equation and the Rogers-Szegő polynomials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2023年第6期66卷 1199-1216页

作者： zhiguo liu School of Mathematical Sciences East China Normal UniversityShanghai 200241China

By solving a q-operational equation with formal power series,we prove a new q-exponential operational *** operational identity reveals an essential feature of the Rogers-Szegő polynomials and enables us to develop a systematic method to prove the identities involving the Rogers-Szegő *** this operational identity,we can easily derive,among others,the q-Mehler formula,the q-Burchnall formula,the q-Nielsen formula,the q-Doetsch formula,the q-Weisner formula,and the Carlitz formula for the Rogers-Szegő *** operational identity also provides a new viewpoint on some other basic *** allows us to give new proofs of the q-Gauss summation and the second and third transformation formulas of Heine and give an extension of the q-Gauss summation.

关键词： q-series q-derivative q-operational equation q-exponential operator Rogers-Szegőpolynomial

Nonlinear Dynamics of Phase Separation in CuCo Alloys

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1994年第10期11卷 634-637页

作者： liu Junming liu zhiguo WU Zhuangchun National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210008

The dynamics of phase separation of CuCo alloys has been studied by numerically solving the nonlinear Cahn-Hilliard equation including thermal *** simulations show that phase separation of the alloys within the metastable region is attributed to the composition fluctuations including thermal *** present modeling makes it possible to describe the growth and coarsening as concomitant processes.

关键词： alloys separation metastable

Distributed Containment Control of Networked Nonlinear Second-order Systems With Unknown Parameters

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2018年第1期5卷 232-239页

作者： Long Ma Haibo Min Shicheng Wang Yuan liu zhiguo liu Unit 96630 of PLA Beijing 102206 China High-tech Institute of Xi'an Xi'an 710025 China

In this paper, we study the containment control problem for nonlinear second-order systems with unknown parameters and multiple stationary/dynamic leaders. The topologies that characterize the interaction among the leaders and the followers are directed graphs. Necessary and sufficient criteria which guarantee the control objectives are established for both stationary leaders(regulation case) and dynamic leaders(dynamic tracking case) based protocols. The final states of all the followers are exclusively determined by the initial values of the leaders and the topology structures. In the regulation case, all the followers converge into the convex hull spanned by the leaders,while in the dynamic tracking case, not only the positions of the followers converge into the convex hull but also the velocities of the followers converge into the velocity convex hull of the ***, all the theoretical results are illustrated by numerical simulations.

关键词： Containment control directed network topology multi-agent systems nonlinear second-order systems

Auto-Oscillations and Chaotic Behavior in Plasma

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1994年第1期11卷 24-27页

作者： LÜKecheng CHANG Shuren liu zhiguo Department of Physics Nankai UniversityTianjin 300071

Auto-oscillations and chaotic behavior were investigated experimentally in a plasma system produced by discharge through mixing He-Ne *** glow power spectra and the differential phase-space portraits show period-doubling and Ruelle-Takens routes to *** windows embedded in chaos and multiple subharmonic bifurcations occurring in the windows were observed.

关键词： Auto chaos. doubling

Pulsed Laser Deposition of Optical Waveguiding LiNbO_(3) Films on SiO_(2) Substrate

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1995年第4期12卷 249-252页

作者： GUO Xinli liu Junming liu zhiguo ZHU Shining National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093 Center for Advanced Studies in Science and Technology of Microstructures Nanjing 210093

The optical waveguiding lithium niobate(LiNbO_(3))films have been prepared on(001)-oriented SiO_(2) substrates by pulsed lager deposition *** x-ray diffraction and scanning electron microscopy were used to characterize the as-grown films,and revealed that highly(012)-textured LiNbO_(3) films with smooth surface were *** optical waveguiding properties of these films were demonstrated by m-line measurements of transverse-magnetic and transverse-electric multimodes.

关键词： technique transverse films

Dynamics of Spacing Selection for Lamellar Eutectics in Directional Solidification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1993年第4期10卷 253-256页

作者： liu Junming liu zhiguo WU Zhuangchun National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210008

Profile and its splitting features of solidifying interface of lamellar eutectic in directional solidification have been investigated by solving numerically the nonlinear coupling equation of *** is argued that critical splitting point of the solidifying interface Is marginally stable,and therefore is the possible operating point of spacing selection *** modes of the dynamics are proposed,and a new scaling law of the lamellar array is derived,which has a more general form than the classic one.

关键词： dynamics splitting interface

Challenges in Atomic-Scale Characterization of High-k Dielectrics and Metal Gate Electrodes for Advanced CMOS Gate Stacks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2009年第3期25卷 289-313页

作者： Xinhua Zhu Jian-min Zhu Aidong Li zhiguo liu Naiben Ming National Laboratory of Solid State Microstructures Department of Physics Nanjing University Nanjing 210093 China

The decreasing feature sizes in complementary metal-oxide semiconductor （CMOS） transistor technology will require the replacement of SiO2 with gate dielectrics that have a high dielectric constant （high-k） because as the SiO2 gate thickness is reduced below 1.4 nm, electron tunnelling effects and high leakage currents occur in SiO2, which present serious obstacles to future device reliability. In recent years significant progress has been made on the screening and selection of high-k gate dielectrics, understanding their physical properties, and their integration into CMOS technology. Now the family of hafnium oxide-based materials has emerged as the leading candidate for high-k gate dielectrics due to their excellent physical properties. It is also realized that the high-k oxides must be implemented in conjunction with metal gate electrodes to get sufficient potential for CMOS continue scaling. In the advanced nanoscale Si-based CMOS devices, the composition and thickness of interfacial layers in the gate stacks determine the critical performance of devices. Therefore, detailed atomic- scale understandings of the microstructures and interfacial structures built in the advanced CMOS gate stacks, are highly required. In this paper, several high-resolution electron, ion, and photon-based techniques currently used to characterize the high-k gate dielectrics and interfaces at atomic-scale, are reviewed. Particularly, we critically review the research progress on the characterization of interface behavior and structural evolution in the high-k gate dielectrics by high-resolution transmission electron microscopy （HRTEM） and the related techniques based on scanning transmission electron microscopy （STEM）, including high-angle annular dark- field （HAADF） imaging （also known as Z-contrast imaging）, electron energy-loss spectroscopy （EELS）, and energy dispersive X-ray spectroscopy （EDS）, due to that HRTEM and STEM have become essential metrology tools for characterizing the d

关键词： High-k gate dielectrics Metal gate electrodes, CMOS gate stack HRTEM STEM

Evaluation of offline sampling for atmospheric C3-C11 non-methane hydrocarbons

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2022年第3期34卷 132-140页

作者： zhiguo liu Chengtang liu Zhouming He Yujing Mu Chenglong Zhang Yuanyuan Zhang Pengfei liu Yuzheng Wang Junfeng liu Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Center for Excellence in Urban Atmospheric Environment Institute of Regional EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China Clear Science&Technology Co. LtdBeijing 100029China

The concentration variation of C3-C11 non-methane hydrocarbons(NMHCs)collected in several types of commercial flexible bags and adsorption tubes was systematically inves-tigated using a gas chromatography-flame ionization detector(GC-FID)*** per-centage loss of each NMHC in the polyvinyl fluoride(PVF)bags was less than 5%during a 7-hr storage period;significant NMHCs loss was detected in aluminum foil composite film and fluorinated ethylene propylene *** thermal desorption efficiency of NMHCs for adsorption tubes filled Carbopack B and Carboxen1000 sorbents was greater than 95%at 300℃,and the loss of NMHCs in the adsorption tubes during 20-days storage at 4℃was less than 8%.The thermal desorption efficiency for C11 NMHCs in the adsorption tube filled with Carbograph 1 and Carbosieve SⅢabsorbents was less than 40%at 300℃,and pyrolysis of the absorbents at 330℃interfered significantly with the measurements of some *** loss of alkenes was significant when NMHCs were sampled by cryo-enrichment at-90℃in the presence of O3 for the online NMHC measurements,and negligible for enrichment us-ing adsorption tubes at 25℃.Although O_(3)scrubbers have been widely used to eliminate the influence of O_(3)on NMHC measurements,the loss of NMHCs with carbon numbers greater than 8 was more than 10%.Therefore,PVF bags and adsorption tubes filled Carbopack B and Carboxen1000 sorbents were recommended for the sampling of atmospheric NMHCs.

关键词： Non-methane hydrocarbons(NMHCs) Gas chromatography-flame ionization detector(GC-FID) Offline sampling Adsorption tubes Ozone scrubber