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Foreign Trade Survey Data:Do They Help in Forecasting Exports and Imports?

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Journal of Systems Science & Complexity 2022年第5期35卷 1839-1862页

作者： bai yun WANG Shouyang ZHANG Xun Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China School of Economics and Management University of Chinese Academy of SciencesBeijing 100190China Center for Forecasting Science Chinese Academy of SciencesBeijing 100190China

Business survey,which starts from the microeconomic level,is a widely used short-term forecasting tool in *** this study,the authors examine whether foreign trade survey data collected by China’s Ministry of Commerce would provide reliable forecasts of China’s foreign *** research procedure is designed from three perspectives including forecast information test,turning point forecast,and out-of-sample value ***,Granger causality test detects whether survey data lead exports and ***,business cycle analysis,a non-model based method,is *** authors construct composite indexes with business survey data to forecast turning points of foreign ***,model-based numerical forecasting methods,including the Autoregressive Integrated Moving Average Model with Exogenous Variables(ARIMAX)and the artificial neural networks(ANNs)models are *** results show that survey data granger cause imports and exports,the leading composite index provides signal for changes of trade cycles,and quantitative models including survey data generate more accurate forecasts than benchmark *** is concluded that trade survey data has excellent predictive capabilities for imports and exports,which can offer some priorities for government policy-making and enterprise decision making.

关键词： ARIMAX artificial neural network composite index forecasting foreign trade Granger causality test survey data

Comparative study on foundation treatment methods of immersed tunnels in China

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Frontiers of Structural and Civil Engineering 2020年第1期14卷 82-93页

作者： Shaochun WANG Xuehui ZHANG yun bai Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

Based on engineering practices of four typical traffic immersed tunnels built in China,this paper details the features of the four dominant foundation treatment methods for immersed tunnel construction:pile foundation,sand flow foundation,grouting foundation,and gravel bedding *** stress time-history of different method are specified first,plus a summary of settlement assessment method for foundation quality ***,a comprehensive comparison of settlement and cost of these four foundation treatment methods is conducted to highlights the specific merits,disadvantages and conditions encountered in each foundation treatment method,based on real projects *** findings of this article could henceforth be applied to foundation treatment work in immersed tube tunnel construction.

关键词： foundation treatment method immersed tunnel subsoil stress settlement

The influence of hand hole on the ultimate strength and crack pattern of shield tunnel segment joints by scaled model test

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Frontiers of Structural and Civil Engineering 2019年第5期13卷 1200-1213页

作者： Shaochun WANG Xi JIANG yun bai Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

With the shield tunnel going deeper and deeper, the circumferential axial force becomes the governing factor rather than the bending moment. The hand hole acts as a weak point and initial damage in the segment joint especially when the circumferential axial force is extremely high. Despite the wide application of steel fiber or synthetic fiber in t|ie tunneling, limited researches focus on the structural responses of segment joint with macro structural synthetic fiber (MSSF). In this paper, a 1:2 reduced-scale experiment was conducted to study the structural perfonnance of the segment joint with different types of hand holes under ultra-high axial force. Special attention is paid to failure mode and structural performance (bearing capacity, deformation, cracking, and toughness). Moreover, segment joints with MSSF are also tested to evaluate the effects of MSSF on the failure mode and structural performance of the segment joints. The experiment results show that the hand hole becomes the weakest point of the segment joint under ultra-high axial force. A\/-type crack pattern is always observed before the final failure of the segment joints. Different types and sizes of the hand hole have different degree of influences on the structural behavior of segment joints. The segment joint with MSSF shows higher ultimate bearing capacity and toughness compared to segment joint with common concrete. Besides, the MSSF improves the initial cracking load and anti-spallling resistance of the segment joint.

关键词： shield tunneling structural synthetic fiber concrete hand hole segment joint ultimate bearing capacity crack pattern

A Quantitative Version of the Bishop–Phelps Theorem for Operators in Hilbert Spaces

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Acta Mathematica Sinica,English Series 2012年第10期28卷 2107-2114页

作者： Li Xin CHENG yun bai DONG School of Mathematical Sciences Xiamen University

In this paper, with the help of spectral integral, we show a quantitative version of the Bishop-Phelps theorem for operators in complex Hilbert spaces. Precisely, let H be a complex Hilbert space and 0 〈 s 〈 1/2. Then for every bounded linear operator T ： H → H and x0 ∈ H with ｜｜T｜｜ = 1 = ｜｜xo｜｜ such that ｜｜Txo｜｜〉 1-6, there exist xε ∈ H and a bounded linear operator S ： H → H with ｜｜S｜｜ = 1 = ｜｜xε｜｜ such that ｜｜Sxε｜｜=1, ｜｜x-ε0｜｜≤√2ε＋4√2ε, ｜｜S-T｜｜≤√2ε.

关键词： Norm attaining operator Hilbert space Bishop-Phelps theorem

Exponentially many maximum genus embeddings and genus embeddings for complete graphs

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Science China Mathematics 2008年第11期51卷 2013-2019页

作者： REN Han bai yun Department of Mathematics East China Normal UniversityShanghai 200062China

There are many results on the maximum genus, among which most are written for the existence of values of such embeddings, and few attention has been paid to the estimation of such embeddings and their applications. In this paper we study the number of maximum genus embeddings for a graph and find an exponential lower bound for such numbers. Our results show that in general case, a simple connected graph has exponentially many distinct maximum genus embeddings. In particular, a connected cubic graph G of order n always has at least $ (\sqrt 2 )^{m + n + \tfrac{\alpha } {2}} $ distinct maximum genus embeddings, where α and m denote, respectively, the number of inner vertices and odd components of an optimal tree T. What surprise us most is that such two extremal embeddings (i.e., the maximum genus embeddings and the genus embeddings) are sometimes closely related with each other. In fact, as applications, we show that for a sufficient large natural number n, there are at least $ C2^{\tfrac{n} {4}} $ many genus embeddings for complete graph K n with n ≡ 4, 7, 10 (mod12), where C is a constance depending on the value of n of residue 12. These results improve the bounds obtained by Korzhik and Voss and the methods used here are much simpler and straight.

关键词： maximum genus embedding optimal tree current graph 05C10

Accumulated Rotation of A Modified Suction Caisson and Soil Deformation Induced by Cyclic Loading

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China Ocean Engineering 2020年第3期34卷 441-449页

作者： bai yun LI Da-yong ZHANG Yu-kun Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Shandong University of Science and TechnologyQingdao 266590China College of Civil Engineering Fuzhou UniversityFuzhouFujian 350108China

Modified suction caissons(MSCs)acting as offshore wind turbine foundations will generate the accumulated rotation under cyclic loading resulted from *** accumulated rotation and the range of soil deformation around the MSC under long-term cyclic wave loading were studied using 3-D numerical *** Morison equation was adopted to calculate the wave *** was found that the MSC accumulated rotation increases linearly with the increase of the logarithm of cyclic *** normalized expression was proposed to reflect the relationship between the accumulated rotation and cyclic *** soil deformation range around the MSC increases when increasing the cyclic number and loading *** can also be concluded that the accumulated rotation increases rapidly with this change of excess pore pressure in the first 4000 *** responses of the MSC to wave and wind loads were also *** show that the accumulated rotation of the MSC under both wave and wind loadings is larger than that under the wave loading only.

关键词： modified suction caisson(MSC) wave loading accumulated rotation soil deformation range

Uniform Homeomorphisms of Unit Spheres and Property H of Lebesgue–Bochner Function Spaces

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Acta Mathematica Sinica,English Series 2017年第5期33卷 681-690页

作者： Qing Jin CHENG yun bai DONG School of Mathematical Sciences Xiamen University School of Mathematics and Computer Wuhan Textile University

Assume that the unit spheres of Banach spaces X and Y are uniformly *** we prove that all unit spheres of the Lebesgue–Bochner function spaces Lp(μ, X) and Lq(μ, Y)are mutually uniformly homeomorphic where 1 ≤ p, q < ∞. As its application, we show that if a Banach space X has Property H introduced by Kasparov and Yu, then the space Lp(μ, X), 1 ≤ p < ∞,also has Property H.

关键词： Banach space uniform classification Property H Novikov conjecture

Protecting geometric quantum discord via partially collapsing measurements of two qubits in multiple bosonic reservoirs

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Chinese Physics B 2022年第4期31卷 163-169页

作者： Xue-yun bai Su-Ying Zhang Institute of Theoretical Physics and State Key Laboratory of Quantum Optics and Quantum Optics Devices Shanxi UniversityTaiyuan 030006China

We study the dynamics of geometric quantum discord(GQD) between two qubits,each qubit interacting at the same time with K independent multiple bosonic reservoirs at zero *** both weak and strong qubit-reservoirs coupling regimes,we find that the increase of the number K of reservoirs can induce the damped oscillation of GQD,and enhance the memory effects of the overall *** the Hilbert-Schmidt norm GQD(two-norm GQD) is always smaller than the trace norm geometric quantum discord(one-norm GQD).Therefore,the one-norm GQD is a better way to measure the quantum ***,we propose an effective strategy to improve GQD by using partially collapsing measurements,and we find that the protection effect is better with the increase of the weak measurement strength.

关键词： geometric quantum discord(GQD) the Hilbert-Schmidt norm GQD the trace norm GQD partially collapsing measurements

Role-based approaches for operational tasks modeling and flexible decomposition

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Journal of Systems Engineering and Electronics 2016年第6期27卷 1191-1206页

作者： ZhigangZou Wangfang Che Shusheng Wang yun bai Chengli Fan Science and Technology on Complex Aviation Systems Simulation Laboratory Beijing 100076China Air and Missile Defense College Air Force Engineering UniversityXi’an 710051China Department of Information Operation&Command Training National Defense University of PLABeijing 100091China

In order to realize the fact that operational tasks can be decomposed flexibly with new tasks random adding, role-based approaches for operational tasks model and the flexibility decomposition are proposed. Firstly, aiming at the shortcomings of previous task decomposition methods, operational role concepts are introduced to design a computing framework of task flexibility decomposition. Within the framework, task structure matrixes are constructed for tasks decomposition with the mapping relations of information interaction and action process among tasks. On basis of this, via giving operational decomposition granularity, a flexibility approach of operational task decomposition is put forward with three parts about task decomposition granularity adjustment, tasks module partition with different operational role patterns and task decomposition scheme evaluation. Finally, as an application case shown, it is validated that the proposed approaches for tasks modeling and decomposition are available. By comparing with previous decomposition approaches, the proposed approach, within three types of operational roles, has strong environmental adaptability and scheme diversity, which can restrain calculation complexity increment for realizing task flexible decomposition effectively. © 2016 Beijing Institute of Aerospace Information.

关键词： Electronics industry Engineering Industrial engineering