• 제목/요약/키워드: Liu system

검색결과 1,136건 처리시간 0.027초

Application of storm water management model to designing the sponge city facilities in the Athletes Village of Military World Games in Wuhan

  • Liu, Jian;Liu, Yan;Liu, Ru;Li, Sixin;Wu, Lingyi
    • 국제학술발표논문집
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    • The 7th International Conference on Construction Engineering and Project Management Summit Forum on Sustainable Construction and Management
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    • pp.346-352
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    • 2017
  • This study discusses application of the storm water management model (SWMM) to designing the sponge city facilities in the Athletes Village of Military World Games in Wuhan in October 2019. The SWMM was used to simulate the runoff processes and reduction efficiencies of the sponge city facilities. The runoffs of the sponge city facilities were compared with those of traditional drainage system for the design rainfall of 35.2mm and the rainfalls with different recurrence periods. The results show that the hign density sponge city facilities could meet the requirements for 80% of annual runoff control rate, SWMM can determine the scales of the sponge city facilities and effectively simulate the hydrological processes for different layout schemes. The simulation model is also helpful to making optimization of the sponge city facility layout.

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Security Improvement of ID-based Multiple Key Management Scheme for t Scalable Ad Hoc Networks

  • 박요한;박영호;문상재
    • 한국산업정보학회논문지
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    • 제16권2호
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    • pp.13-18
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    • 2011
  • Security supports are a significant factor in mobile ad hoc networks. Especially in dynamic topologies, considering cluster, key management is essential to provide a secure system. Recently, Li-Liu proposed iD-based multiple key management scheme for cluster-based ad hoc networks. However, we found the security weakness of their scheme. In this paper, we analyze the security of Li-Liu's scheme and show that master secret key and fragment of the master secret key can be revealed to compromised CHs and nodes. Furthermore, we propose a solution to improve the scheme against disclosure of the share key and the master secret key even though system parameters are opened to compromised nodes and modify the Li-Liu's scheme fitted for a scalable networks. The improved IMKM scheme could be usefully applied in dynamic cluster-based MANETs such as the military battlefields, mobile marketplace and VANETs.

STUDY ON THE AGRICULTURAL MECHANIZATION SERVICE SYSTEM CONSTRUCTION IN GUANGDONG PROVINCE

  • Shengmin, Liu
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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    • pp.192-196
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    • 1993
  • Following the transfer of China's economy from planning to market economy, it is necessary to develop and strength the service system for agricultural mechanization . The current situation of the service system was investigated and some suggestions are proposed in this paper.

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Study on Influences and Elimination of Test Temperature on PDC Characteristic Spectroscopy of Oil-Paper Insulation System

  • Liu, Xiao;Liao, Ruijin;Lv, Yandong;Liu, Jiefeng;Gao, Jun;Hao, Jian
    • Journal of Electrical Engineering and Technology
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    • 제10권3호
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    • pp.1107-1113
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    • 2015
  • Test temperature is an important factor affecting the measurement results of dielectric response of field power transformers. In order to better apply the polarization and depolarization current (PDC) to the condition monitoring of oil-paper insulation system in power transformers, the influences and elimination method of test temperature on PDC characteristic spectroscopy (PDC-CS) were investigated. Firstly, the experimental winding sample was measured by PDC method at different test temperatures, then the PDC-CS was obtained from the measurement results and its changing rules were discussed, which show that the PDC-CS appears a horizontal mobility with the rise of temperature. Based on the rules, the “time temperature shift technique” was introduced to eliminate the influence of test temperature. It is shown that the PDC-CS at different test temperatures can be converted to the same reference temperature coincident with each other.

Application of AIS in AtoN Wireless Surveillance System

  • Liu, Chang;Liu, Ren-Jie;Shi, Xiao-Fei;Huang, Yao-Liang
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2006년도 Asia Navigation Conference
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    • pp.129-133
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    • 2006
  • In China, the traditional method of artificial and periodical cruise is still adopted for the AtoN management, which has brought many disadvantages to the work of the AtoN management, such as non real-time, fallibility, and low efficiency However, with the rapid development of AIS technique, now AIS equipments have been widely installed on ships, and on the other hand China Maritime Safety Administration (abr. China MSA) is carrying out the scheme of AIS base station network in china, based on which the digital AtoN will develop in the future. According to what have been analyzed above, this paper puts forward a design of AtoN wireless surveillance system based on AIS. The system consists of AIS on AtoN, AIS base station and AtoN management center. It can provide such functions as the information gathering, managing of AtoN and the service of navigation assistance. This paper gives the whole design including the work theory, the hardware structure and the software scheme of the system, and finally gives the simulation software of the AtoN management center. The AtoN wireless surveillance system brought forward by this paper will be more efficient with less repair cost and less work of the supervisors. It will bring revolutionary progress in the navigation aids system in China.

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Vibration suppression analysis of a long-span cable-stayed bridge based on earthquake-wind-traffic-bridge coupled system

  • Xinfeng Yin;Yong Liu;Wanli Yan;Yang Liu;Zhou Huang
    • Structural Engineering and Mechanics
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    • 제88권4호
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    • pp.379-387
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    • 2023
  • Wind and earthquake loads may cause strong vibrations in large-span cable-stayed bridges, leading to the inability of the bridge to operate normally. An improved Pounding Tuned Mass Damper (PTMD) system was designed to improve the safety of the large-span cable-stayed bridge. The vibration control effect of the improved PTMD system on the large-span cablestayed bridge under the combined action of earthquake-wind-traffic was studied. Furthermore, the impact of different parameters on the vibration suppression performance of the improved PTMD system was analyzed. The numerical results indicate that the PTMD system is very effective in suppressing the displacements of the bridge caused by both the traffic-wind coupling and traffic-earthquake coupling. Moreover, the number, mass ratio, pounding stiffness, and gap values have a significant influence on the vibration suppression performance of the improved PTMD system. When the number of PTMD is increased from 3 to 9, the vibration reduction ratio of the vertical displacement is increased from 25.39% to 48.05%. As the mass ratio changes from 0.5% to 2%, the vibration reduction ratio increases significantly from 22.23% to 53.30%.

A cosmic ray muons tomography system with triangular bar plastic scintillator detectors and improved 3D image reconstruction algorithm: A simulation study

  • Yanwei Zhao;Xujia Luo;Kemian Qin;Guorui Liu;Daiyuan Chen;R.S. Augusto;Weixiong Zhang;Xiaogang Luo;Chunxian Liu;Juntao Liu;Zhiyi Liu
    • Nuclear Engineering and Technology
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    • 제55권2호
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    • pp.681-689
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    • 2023
  • Purpose: Muons are characterized by a strong penetrating ability and can travel through thousands of meters of rock, making them ideal to image large volumes and substances typically impenetrable to, for example, electrons and photons. The feasibility of 3D image reconstruction and material identification based on a cosmic ray muons tomography (MT) system with triangular bar plastic scintillator detectors has been verified in this paper. Our prototype shows potential application value and the authors wish to apply this prototype system to 3D imaging. In addition, an MT experiment with the same detector system is also in progress. Methods: A simulation based on GEANT4 was developed to study cosmic ray muons' physical processes and motion trails. The yield and transportation of optical photons scintillated in each triangular bar of the detector system were reproduced. An image reconstruction algorithm and correction method based on muon scattering, which differs from the conventional PoCA algorithm, has been developed based on simulation data and verified by experimental data. Results: According to the simulation result, the detector system's position resolution is below 1 ~ mm in simulation and 2 mm in the experiment. A relatively legible 3D image of lead bricks in size of 20 cm × 5 cm × 10 cm used our inversion algorithm can be presented below 1× 104 effective events, which takes 16 h of acquisition time experimentally. Conclusion: The proposed method is a potential candidate to monitor the cosmic ray MT accurately. Monte Carlo simulations have been performed to discuss the application of the detector and the simulation results have indicated that the detector can be used in cosmic ray MT. The cosmic ray MT experiment is currently underway. Furthermore, the proposal also has the potential to scan the earth, buildings, and other structures of interest including for instance computerized imaging in an archaeological framework.

Volumetric 3D Display System Based on Rotating Dot-Matrix LEDs

  • Lin, Yuanfang;Liu, Xu;Zhang, Xiaojie;Yao, Yi;Liu, Xiangdong
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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    • pp.440-441
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    • 2004
  • A volumetric three-dimensional (3D) display system was presented, which utilizes a rotating two-dimensional (2D) display panel of light emitting diodes (LEDs) to generate more than 10 million volume pixels (voxels) within a cylindrical volume of 165 mm in height and 292 mm in diameter. Due to persistence of vision, momentarily addressed voxel information is perceived and fused into a 3D image. Important cues for depth perception, such as binocular parallax, accommodation, convergence and motion parallax are satisfied automatically and naturally, thus it is suitable for individual or group viewing, without the need for any special visual aids.

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Parametric Analysis and Design Engine for Tall Building Structures

  • Ho, Goman;Liu, Peng;Liu, Michael
    • 국제초고층학회논문집
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    • 제1권1호
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    • pp.53-59
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    • 2012
  • With the rise in CPU power and the generalization and popularity of computers, engineering practice also changed from hand calculations to 3D computer models, from elastic linear analysis to 3D nonlinear static analysis and 3D nonlinear transient dynamic analysis. Thanks to holistic design approach and current trends in freeform and contemporary architecture, BIM concept is no longer a dream but also a reality. BIM is not just providing a media for better co-ordination but also to shorten the round-the-clock time in updating models to match with other professional disciplines. With the parametric modeling tools, structural information is also linked with BIM system and quickly produces analysis and design results from checking to fabrication. This paper presents a new framework which not just linked the BIM system by means of parametric mean but also create and produce connection FE model and fabrication drawings etc. This framework will facilitate structural engineers to produce well co-ordinate, optimized and safe structures.

Effect of temperature and spring-mass systems on modal properties of Timoshenko concrete beam

  • Liu, Hanbing;Wang, Hua;Tan, Guojin;Wang, Wensheng;Liu, Ziyu
    • Structural Engineering and Mechanics
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    • 제65권4호
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    • pp.389-400
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    • 2018
  • An exact solution for the title problem was obtained in closed-form fashion considering general boundary conditions. The expressions of moment, shear and shear coefficient (or shear factor) of cross section under the effect of arbitrary temperature distribution were first derived. In view of these relationships, the differential equations of Timoshenko beam under the effect of temperature were obtained and solved. Second, the characteristic equations of Timoshenko beam carrying several spring-mass systems under the effect of temperature were derived based on the continuity and force equilibrium conditions at attaching points. Then, the correctness of proposed method was demonstrated by a Timoshenko laboratory beam and several finite element models. Finally, the influence law of different temperature distribution modes and parameters of spring-mass system on the modal characteristics of Timoshenko beam had been studied, respectively.