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A General Jury Theorem on Group Decision Making

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Journal of the Operations Research Society of China 2021年第4期9卷 869-881页

作者： yu-Da hu School of Mathematical Sciences Shanghai Jiaotong UniversityShanghai 200240China

This paper established a general jury theorem on group decision making where the probabilities of the individuals in making correct choice between two alternatives can be *** we proved that the higher the probability of any decision maker in the group correctly choosing between two alternatives,the higher the probability of the group correctly choosing the same two *** general jury theorem also indicates that given two groups of individuals with the same average probability of making the correct choice,the one with a more varied or diverse distribution of probabilities will have a higher probability of making the correct *** particular,we proved that as the number of decision makers in the group increases to infinity,this probability tends to the limit *** general jury theorem presented in this paper substantially generalizes the well-known Condorcet jury theorem in the group decision making theory,which has not been generalized for 200 years until now.

关键词： Group decision making Preference relation Condorcet jury theorem Probability

Mechanism of interconnected synchronized switch damping for vibration control of blades

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Chinese Journal of Aeronautics 2023年第8期36卷 207-228页

作者： yu FAN yu hu Yaguang WU Lin LI School of Energy and Power Engineering Beihang UniversityBeijing 100191China Beijing Key Laboratory of Aero-engine Structure and Strength Beijing 100191China Sino-French Engineering School Beihang UniversityBeijing 100191China

The Synchronized Switch Damping(SSD)is regarded as a promising alternative to mitigate the vibration of thin-walled structures in aero-engines,especially for blades or bladed *** common manner is to shunt the switch circuit independently to a single piezoelectric *** paper is aimed at exploring a novel way of using the SSD,i.e.,the SSD is interconnected between two piezoelectric structures or *** damping mechanism,performance,and effective range of the interconnected SSD are studied numerically and ***,based on a dual cantilever beam finite element model,the time domain and frequency domain modeling and solving methods of the interconnected SSD are deduced and ***,the influence of the amplitude and phase relationship on the damping effect of the interconnected SSD is numerically studied and compared with the shunted SSD.A self-sensing SSD control board is developed,and experimental studies are carried *** results show that the interconnected SSD establishes an additional energy channel between the corresponding piezoelectric *** the amplitudes of the two cantilever beams are different,the interconnected SSD balances the vibration level of each *** the amplitudes of the two cantilever beams are the same,if the appropriate interconnection manner is selected according to the phase,the resonance peak can be reduced by more than 30%.When the vibration is in-phase/out-of-phase,the damping generated by the interconnected SSD in a cross/parallel manner is even more significant than the shunted ***,this novel connection scheme reduces the number of SSD circuits in ***,for engineering applications,we implement the proposed damping technology to the finite element model of a typical dummy bladed disk.A piezoelectric damping ratio of 13.7%is achieved when the amount of piezo material is only 10%of blade *** with traditional friction dampers,the major advancements of t

关键词： Blade Dry friction damping Experiments Finite element method Piezoelectric Synchronized switch damping

Spatiotemporal Evolution and Influencing Factors of Landscape Ecological Vulnerability in the Three-River-Source National Park Region

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Chinese Geographical Science 2022年第5期32卷 852-866页

作者： yu hu ZHANG Xiaoyao DENG yu Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment Chinese Academy of SciencesBeijing 100049China

The increasing impact of global warming and human activities has exacerbated the ecological environment in the Three-RiverSource National Park Region(TNPR). Understanding the temporal and spatial evolution of landscape ecological vulnerability(LEV)and its influencing factors are crucial to the implementation of environmental management. Here, we aimed to: 1) construct a LEV assessment model integrating landscape structure and function;2) analyze the temporal and spatial evolution of TNPR’s LEV from 1995to 2015;3) use geographic detectors to reveal the regional influence factors of TNPR’s LEV. The main findings were: 1) grasslands, water, and bare land are important landscapes of TNPR, accounting for 98.37% of the total area. During the study period, there were significant differences in the area of different landscapes;except for desert, shrub, and urban land, the other landscape areas showed a decreasing trend. 2) During the study period, the LEV of TNPR showed a downward trend;except for grasslands, the ecological vulnerability of the other landscapes decreased steadily. Furthermore, a pattern of conversion from high to low vulnerability grade was observed in the study area. In terms of spatial distribution, the LEV level shows a trend of high at both ends(east and west) and low in the middle.3) Overall, the impact of natural factors on the ecological vulnerability of the TNPR was significantly higher than that of human *** conclusion, our study provides a scientific basis for landscape structure optimization and the management of regional ecological vulnerability.

关键词： landscape structure landscape function landscape ecological vulnerability geographical detectors influencing factors Three-River-Source National Park

Morphology of metal nanoparticles photodeposited on TiO_2/silical gel and photothermal activity for destruction of ethylene

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Journal of Environmental Sciences 2006年第1期18卷 76-82页

作者： hu Chun LIN Lan-yu hu Xue-xiang Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beij ing 100085 China

The morphology of supported metal nanoparticles on TiO2/silical gel （TSO） and photothermal synergism were investigated for destruction of ethylene. During photocatalytic deposition of metal nanopartilces, the effects of pH and light intensity on the morphology of coated platinum, palladium, gold on TiO2/silical gel were studied. Moreover, these catalysts were characterized by TEM, UV-Vis DRS. The pH of preparing solution have strong influence on dispersion, size and sites of Pt, Pd and Au on TSO, which were controlled by the electrostatic binding of HPtCl5^- AuCl4^- and TiOH2^＋, Pd^2＋ and TiO^- respectively. Platinum, gold and palladium nanoparticles were uniformly highly dispersed on the titanol sites not silanol of TiO2/silical gel under pH=2, pH =9.9 respectively. For the photodegradation of ethylene, they show higher photothermal efficiency than those prepared with other pH conditions under UV illumination in a non-circulating photoreactor. The optimum weight loadings of Pt, Au, and Pd were 0.25 wt%, 0.5 wt%, 1 wt%, respectively. The synergistic effect enhanced ethylene removal and CO2 production. Thcse results verify that the best photothermal synergistic effect depends on the dispersion, size of noble metal nano-particles. FTIR analyses of the used Pt-, Pd-TSO catalysts indicated that no significant by-products were accumulated on the surface of the catalysts, leading to them longer lifetime.

关键词： photodeposition TiO2/silical gel noble metal dispersion photothermal synergism

Two-Type Information Fusion Based IP-to-AS Mapping Table Refining

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Journal of Computer Science & Technology 2017年第3期32卷 571-584页

作者： Qing Jiang Hang-yu hu Guang-Min hu School of Communication and Information Engineering University of Electronic Science and Technology of China Chengdu 611731 China

The Internet topology at the autonomous system （AS） level is of great importance, and traceroute has been known to be a potential tool to obtain a complete AS topology. The original IP-to-AS mapping table maps the IP addresses in traceroute paths to their origin ASes, which may cause false AS links. The existing methods refine the original mapping table based on traceroute-BGP path pairs or alias resolution data. However, the information extracted from either of them is inaccurate and incomplete. In this paper, we present a two-type information fusion based method to refine the original mapping table. We extract four kinds of information from path pair and alias resolution data. Based on these information, we build a candidate AS set for each router. Then we choose the AS that is consistent with the existing information to be the owner AS of each router and map all of the IP addresses on the router to it. We validate the result with the ground truth from PeeringDB and Looking Glass severs. Compared with the existing methods, our method produces a more accurate mapping table. In addition, we discuss the coverage of our method and show that our method is convergent and more robust against the reduction of information or the increase of incorrect information.

关键词： network topology Internet routers BGP traceroute

Response Sensitivity to Design Parameters of RV Reducer

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Chinese Journal of Mechanical Engineering 2018年第3期31卷 115-127页

作者： yu-hu Yang Chuan Chen Shi-yu Wang School of Mechanical Engineering Tianjin University

Dynamic characteristic significantly a ects performance of RV reducer. The current researches mainly pay attention to free vibration properties of RV reducer. In order to satisfy the increasing demand on high performance,response sensi?tivity is analytically studied on the basis of cyclic symmetry structure. Based on the structure characteristics,a dynamic model is developed by taking into account the influence of bearing sti ness,crankshaft bending sti ness and mesh sti ness within planetary and cycloidal stages. For the model,governing equation of motion is derived and solved by Fourier series method. The solution revealed that forced vibrations at primary frequency are well defined structural. There exist three typical forced vibration modes: rotational,translational and planetary component modes. Response sensitivity to basic design parameters is obtained as closed?form expressions by di erential method. With the typical vibration modes,response sensitivity is simplified and classified into three types. Calculation of sensitivity implies that vibrations of the output wheel are sensitive to eccentricity. As eccentricity increases,sensitivity of translation decreases first and then increases,but sensitivity of rotation always increases. The proposed method for analyzing response sensi?tivity provides some principles for selecting parameters for RV reducer from the point of view of forced vibration.

关键词： RV reducer Mesh phasing Vibration modes Sensitivity

Evolutionary Pattern and Effect of Administrative Division Adjustment During Urbanization of China:Empirical Analysis on Multiple Scales

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Chinese Geographical Science 2018年第5期28卷 758-772页

作者： yu hu DENG yu XU Shan Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Science Key Laboratory of Regional Sustainable Development Modeling Chinese Academy of Science

The adjustment of administrative divisions is one of the important factors guiding China's urbanization, which has profound economic and social effects for regional development. In this paper, we comprehensively describe the process of the adjustment of administrative divisions at provincial and municipal levels in China and summarize the effects on the basic structure and patterns of the spatial development. We quantitatively assess the effects on fields such as urbanization and social economy through the use of multidimensional scaling. The results show that: 1) Upgrading county to municipality(or city-governed district) is the main way of adjusting the administrative divisions. It is also an important factor in the spatial differentiation of interprovincial urbanization. China's population urbanization can be divided into four patterns including interprovincial migration, provincial migration, natural growth, and growth caused by the adjustment of administrative divisions, which is also the main reason for the increased Chinese urbanization rate at the provincial level. 2) Taking the city of Beijing as an example, we generalize five adjustment patterns made to administrative divisions: the set-up of sub-districts, the set-up of regional offices, the upgrading of townships to sub-districts, the upgrading of townships to towns, and the set-up of towns and the addition of new regional offices. We summarize the municipal urban spatial structure, including the sub-district office area in the central urban area, the regional office area in the new urban area, the mixed area of villages, towns, and sub-district offices in the suburb area, and the township area in the outer suburb area. 3) The adjustment of administrative divisions triggers a significant circulative accumulation effect, resulting in the spatial locking of population and industrial agglomeration. It affects the evolution of the urban spatial form and plays an important role in shaping the urban spatial st

关键词： administrative division adjustment evolutionary structure effect evaluation multidimensional scaling urbanization China

Simulation study on fluctuant flow stress scale effect

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第8期7卷 1343-1350页

作者： SHEN yu yu hu-ping RUAN Xue-yu National Die and Mold CAD Engmeering Research Center Shanghai Jiao Tong University Shanghai 200030 China

Crystal plasticity theory was used to simulate upsetting tests of different dimensions and grain size micro copper cylinders in this study on the fluctuant flow stress scale effect. Results showed that with the decrease of billet grain quantity, flow stress fluctuation is not always increased, but there is a maximum. Through this study, the fluctuant flow stress scale effect can be understood deeper, and relevant necessary information was obtained for further prediction and control of this scale effect and to design the microforming process and die.

关键词： Microforming Scale effect Numerical simulation Fluctuation

Synthesis and Characterization of Zirconia Nanocrystallites by Cationic Surfactant and Anionic Surfactant

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Chinese Journal of Structural Chemistry 2005年第10期24卷 1133-1139页

作者： yu Jian-Chang hu Sheng-Wei College of Material Science and Engineering Fuzhou University Fuzhou 350002 China

Study on nanomaterials has attracted great interests in recent years. In this article, zirconia nanocrystallites of different structures have been successfully synthesized via hydrothermal methods with cationic surfactant （CTAB） and anionic surfactant （SDS）, respectively. Differential Scanning Calorimeter （DSC-TG）, X-ray Diffractometer （XRD）, Transmission Electron Microscope （TEM）, Ultraviolet-Visible （UV-vis） and N2 adsorption-desorption analyses are used for their structure characteristics. The results show that the cationic surfactant has a distinctive direction effect on the formation of zirconia nanocrystallites, while the anionic surfactant has a self-assembly synergistic effect on them. The sample synthesized with the cationic surfactant presents good dispersion with the main phase of tetragonal zirconia, and the average nanocrystal size is around 15 nm after calcination at 500 ℃. While the sample synthesized with the anionic surfactant exhibits a worm-like mesoporous structure with pure tetragonal phase after calcination at 500 ℃ and with good thermal stability.

关键词： cationic surfactant anionic surfactant zirconia nanocrystallites,mesoporous zirconia