The discrete element method (DEM) was used to simulate the flow characteristic and strength characteristic of the conditioned sands in the earth pressure balance (EPB) tunneling. In the laboratory the conditioned sand...The discrete element method (DEM) was used to simulate the flow characteristic and strength characteristic of the conditioned sands in the earth pressure balance (EPB) tunneling. In the laboratory the conditioned sands were reproduced and the slump test and the direct shear test of the conditioned sands were implemented. A DEM equivalent model that can simulate the macro mechanical characteristic of the conditioned sands was proposed,and the corresponding numerical models of the slump test and the shear test were established. By selecting proper DEM model parameters,the errors of the slump values between the simulation results and the test results are in the range of 10.3%-14.3%,and the error of the curves between the shear displacement and the shear stress calculated with the DEM simulation is 4.68%-16.5% compared with that of the laboratory direct shear test. This illustrates that the proposed DEM equivalent model can approximately simulate the mechanical characteristics of the conditioned sands,which provides the basis for further simulation of the interaction between the conditioned soil and the chamber pressure system of the EPB machine.展开更多
This study describes discursive and visual features of telephone openings to a live broadcast television call-in program based on the analysis of the ＂multi-unit reason-for-the-call turn＂ （Couper-Kuhlen, 2001）. Th...This study describes discursive and visual features of telephone openings to a live broadcast television call-in program based on the analysis of the ＂multi-unit reason-for-the-call turn＂ （Couper-Kuhlen, 2001）. The data were based on video-recordings of the call-in program broadcast daily on Hakka channel in Taiwan, in which callers call to seek advice on health problems. The discourse analysis shows that callers＇ ＂multi-unit reason-for-the-call turns＂ can be classified into three forms including request, epistemic frame and descriptions of symptoms, and telling of lifestyle. The visual analysis demonstrates that the visual shots of ＂multi-unit reason-for-the-call turns＂ orient viewers to the studio scene in which the invited guest, usually the medical doctor, can be seen listening to callers＇ upcoming questions. Based on the analyses and an interview with the camera director of this television program, the discussion sheds light on how television production practices use callers＇ multi-unit turns as a resource for switching to the studio shot, which helps to build an image of the expert and his/her role and function in the advice-seeking program. In this sense, filming and television production practices rely on linguistic resources and the visualization of callers＇ multi-unit turns has meanings in the organization of studio interaction as ＂institutional interaction＂ （Drew ＆ Heritage, 1992）, being shaped by interactants＇ identities, roles, and tasks relevant for the specific institutional needs or purposes.展开更多
A self-reconfigurable robot is a non-linear complex system composed of a large number of modules. The complexity caused by non-linearity makes it difficult to solve the problem of module motion planning and shape-chan...A self-reconfigurable robot is a non-linear complex system composed of a large number of modules. The complexity caused by non-linearity makes it difficult to solve the problem of module motion planning and shape-changing control with the traditional algorithm. In this paper, a full-discrete metamorphic algorithm is proposed. The modules concurrently process the local sensing information, update their eigenvector, and act by the same predetermined logical rules. Then a reasonable motion sequence for modules and the global metamorphosis can be obtained. Therefore, the complexity of metamorphic algorithm is reduced, the metamorphic procedure is simplified, and the self-organizing metamorphosis can be obtained. The algorithm cases of several typical systems are studied and evaluated through simulation program of 2-D planar homogeneous modular systems.展开更多
With the concept of super-atom, first principles calculations propose a new type of super stable cage clusters AlnH3n that are much more energetic stable than the well established clusters, AlnHn＋2. In the new cluste...With the concept of super-atom, first principles calculations propose a new type of super stable cage clusters AlnH3n that are much more energetic stable than the well established clusters, AlnHn＋2. In the new clusters, the aluminum core-frame acts as a super-atom with n vertexes and 2n A1-A1 edges, which allow to adsorb n hydrogen atoms at the top-site and 2n at the bridge-site. Using Al12H36 as the basic unit, stable chain structures, （Al12H36）m, have been constructed following the same connection mechanism as for （A1H3）n linear polymeric structures. Apart from high hydrogen percentage per molecule, calculations have shown that these new clusters possess large heat of formation values and their combustion heat is about 4.8 times of the methane, making them a promising high energy density material.展开更多
Data Envelopment Analysis （DEA） is a powerful mathematical optimization method widely used for measuring, evaluating and improving the performance of Decision Making Units （DMUs）. These used in the various forms, ...Data Envelopment Analysis （DEA） is a powerful mathematical optimization method widely used for measuring, evaluating and improving the performance of Decision Making Units （DMUs）. These used in the various forms, such as hospitals, government agencies, educational institutions, air force, bank branches, business finns, sport teams and even people including the performance of countries, regions, etc. Recently DEA has been extended to examine the performance through the different sport types. In this paper, a Stochastic Input Oriented Data Envelopment Analysis （SIODEA） Model is conducted for measuring and evaluating the relative efficiency scores of football teams selected from different European countries during 2014/2015 season each with some of inputs are stochastic with normally distributed and recent inputs are deterministic and outputs, to shed light on the professional football teams performance.展开更多
基金Project (2007CB714006) supported by the National Basic Research Program of China
文摘The discrete element method (DEM) was used to simulate the flow characteristic and strength characteristic of the conditioned sands in the earth pressure balance (EPB) tunneling. In the laboratory the conditioned sands were reproduced and the slump test and the direct shear test of the conditioned sands were implemented. A DEM equivalent model that can simulate the macro mechanical characteristic of the conditioned sands was proposed,and the corresponding numerical models of the slump test and the shear test were established. By selecting proper DEM model parameters,the errors of the slump values between the simulation results and the test results are in the range of 10.3%-14.3%,and the error of the curves between the shear displacement and the shear stress calculated with the DEM simulation is 4.68%-16.5% compared with that of the laboratory direct shear test. This illustrates that the proposed DEM equivalent model can approximately simulate the mechanical characteristics of the conditioned sands,which provides the basis for further simulation of the interaction between the conditioned soil and the chamber pressure system of the EPB machine.
文摘This study describes discursive and visual features of telephone openings to a live broadcast television call-in program based on the analysis of the ＂multi-unit reason-for-the-call turn＂ （Couper-Kuhlen, 2001）. The data were based on video-recordings of the call-in program broadcast daily on Hakka channel in Taiwan, in which callers call to seek advice on health problems. The discourse analysis shows that callers＇ ＂multi-unit reason-for-the-call turns＂ can be classified into three forms including request, epistemic frame and descriptions of symptoms, and telling of lifestyle. The visual analysis demonstrates that the visual shots of ＂multi-unit reason-for-the-call turns＂ orient viewers to the studio scene in which the invited guest, usually the medical doctor, can be seen listening to callers＇ upcoming questions. Based on the analyses and an interview with the camera director of this television program, the discussion sheds light on how television production practices use callers＇ multi-unit turns as a resource for switching to the studio shot, which helps to build an image of the expert and his/her role and function in the advice-seeking program. In this sense, filming and television production practices rely on linguistic resources and the visualization of callers＇ multi-unit turns has meanings in the organization of studio interaction as ＂institutional interaction＂ （Drew ＆ Heritage, 1992）, being shaped by interactants＇ identities, roles, and tasks relevant for the specific institutional needs or purposes.
文摘A self-reconfigurable robot is a non-linear complex system composed of a large number of modules. The complexity caused by non-linearity makes it difficult to solve the problem of module motion planning and shape-changing control with the traditional algorithm. In this paper, a full-discrete metamorphic algorithm is proposed. The modules concurrently process the local sensing information, update their eigenvector, and act by the same predetermined logical rules. Then a reasonable motion sequence for modules and the global metamorphosis can be obtained. Therefore, the complexity of metamorphic algorithm is reduced, the metamorphic procedure is simplified, and the self-organizing metamorphosis can be obtained. The algorithm cases of several typical systems are studied and evaluated through simulation program of 2-D planar homogeneous modular systems.
基金This work was supported by the Swedish Research Council, Swedish National Infrastructure for Computing, the National Natural Science Foundation of China （No.10534010 and No.20925311）, the Funda-mental Research Funds for the Central Universities （No.201103255）, and the China Scholarship Council.
文摘With the concept of super-atom, first principles calculations propose a new type of super stable cage clusters AlnH3n that are much more energetic stable than the well established clusters, AlnHn＋2. In the new clusters, the aluminum core-frame acts as a super-atom with n vertexes and 2n A1-A1 edges, which allow to adsorb n hydrogen atoms at the top-site and 2n at the bridge-site. Using Al12H36 as the basic unit, stable chain structures, （Al12H36）m, have been constructed following the same connection mechanism as for （A1H3）n linear polymeric structures. Apart from high hydrogen percentage per molecule, calculations have shown that these new clusters possess large heat of formation values and their combustion heat is about 4.8 times of the methane, making them a promising high energy density material.
文摘Data Envelopment Analysis （DEA） is a powerful mathematical optimization method widely used for measuring, evaluating and improving the performance of Decision Making Units （DMUs）. These used in the various forms, such as hospitals, government agencies, educational institutions, air force, bank branches, business finns, sport teams and even people including the performance of countries, regions, etc. Recently DEA has been extended to examine the performance through the different sport types. In this paper, a Stochastic Input Oriented Data Envelopment Analysis （SIODEA） Model is conducted for measuring and evaluating the relative efficiency scores of football teams selected from different European countries during 2014/2015 season each with some of inputs are stochastic with normally distributed and recent inputs are deterministic and outputs, to shed light on the professional football teams performance.
