A tunneled planing hull has unique hybrid hydrodynamic and aerodynamic characteristics due to the presence of a tunnel.In this paper,experimental and numerical investigations on hydrody namic analysis of a tunneled pl...A tunneled planing hull has unique hybrid hydrodynamic and aerodynamic characteristics due to the presence of a tunnel.In this paper,experimental and numerical investigations on hydrody namic analysis of a tunneled planing hull are carried out.The resistance tests of models with three dif ferent masses(127.4 kg,159.5 kg,202.9 kg)are conducted for the Froude number in the range of 0.761≤Fn≤1.925.The results of resistance measured by towing tank imply that the tunneled planing hull with a larger displacement has a superior resistance performance.The numerical simulation of Reynolds Average Navier Stokes(RANS)equations based on the finite volume method is performed to analyze the hull characteristics in calm water(M=159.5 kg)with two degrees of freedom(sinkage and trim).The numerical results are compared with the experimental data,which shows good agreement.Pressure distribution,wave profiles and lift forces obtained by SST k-ωand Realizable k-εturbulence models are compared and discussed.Finally,the local fluid flow of streamline around the hull can be divided into four regions due to the presence of a tunnel,which is different from the behaviors of the conventional planing monohull with prismatic form.展开更多
Distributed/parallel-processing system like sun grid engine(SGE) that utilizes multiple nodes/cores is proposed for the faster processing of large sized satellite image data. After verification, distributed process en...Distributed/parallel-processing system like sun grid engine(SGE) that utilizes multiple nodes/cores is proposed for the faster processing of large sized satellite image data. After verification, distributed process environment for pre-processing performance can be improved by up to 560.65% from single processing system. Through this, analysis performance in various fields can be improved, and moreover, near-real time service can be achieved in near future.展开更多
A scheduling scheme is proposed to reduce execution time by means of both checkpoint sharing and task duplication under a peer-to-peer(P2P) architecture. In the scheme, the checkpoint executed by each peer(i.e., a res...A scheduling scheme is proposed to reduce execution time by means of both checkpoint sharing and task duplication under a peer-to-peer(P2P) architecture. In the scheme, the checkpoint executed by each peer(i.e., a resource) is used as an intermediate result and executed in other peers via its duplication and transmission. As the checkpoint is close to a final result, the reduction of execution time for each task becomes higher, leading to reducing turnaround time. To evaluate the performance of our scheduling scheme in terms of transmission cost and execution time, an analytical model with an embedded Markov chain is presented. We also conduct simulations with a failure rate of tasks and compare the performance of our scheduling scheme with that of the existing scheme based on client-server architecture. Performance results show that our scheduling scheme is superior to the existing scheme with respect to the reduction of execution time and turnaround time.展开更多
For non-quenchable dual-phase(DP)steel sheet,the warm forming process can effectively reduce the amount of springback,and the mechanical parameters that influence its elastic and inelastic recovery to decrease exhibit...For non-quenchable dual-phase(DP)steel sheet,the warm forming process can effectively reduce the amount of springback,and the mechanical parameters that influence its elastic and inelastic recovery to decrease exhibit a strong temperature dependence,especially under cyclic loading conditions.In this paper,the monotonic and cyclic loading tests of DP980 steel sheets are conducted at the temperatures ranging from 25℃ to 500℃.The temperature-dependent flow stress,nonlinear elastic recovery,and Bauschinger effect are investigated.The results demonstrate that both the elastic modulus and Bauschinger effect show an exponential law with pre-strain,and decrease with the increase of forming temperature,while there will be an abnormal phenomenon of rebound due to the influence of dynamic strain aging effect.Meanwhile,a linear relationship between the Bauschinger effect and inelastic strain is observed at various temperatures,and the weight of the Bauschinger effect in the total strain reduces with temperature increasing,which indicates that the springback is dominated by linear elastic recovery.Furthermore,the U-draw bending tests are carried out to clarify the influence of Vickers hardness distribution and martensite size effect on the springback behavior.展开更多
A good understanding of pedestrian movement in the transfer corridor is vital for the planning and design of the station,especially for efficiency and safety.A multi-force vector grid model was presented to simulate t...A good understanding of pedestrian movement in the transfer corridor is vital for the planning and design of the station,especially for efficiency and safety.A multi-force vector grid model was presented to simulate the movement of bidirectional pedestrian flow based on cellular automata and forces between pedestrians.The model improves rule-based characteristics of cellular automata,details forces between pedestrians and solves pedestrian collisions by a several-step updating method to simulate pedestrian movements.Two general scenarios in corridor were simulated.One is bidirectional pedestrian flow simulation with isolation facility,and the other is bidirectional pedestrian flow simulation without isolation facility,where there exists disturbance in the middle.Through simulation,some facts can be seen that pedestrians in the case with isolation facility have the largest speed and pedestrians in the case without isolation facility have the smallest speed; pedestrians in the case of unidirectional flow have the largest volume and pedestrians in the case of without isolation facility have the smallest volume.展开更多
文摘A tunneled planing hull has unique hybrid hydrodynamic and aerodynamic characteristics due to the presence of a tunnel.In this paper,experimental and numerical investigations on hydrody namic analysis of a tunneled planing hull are carried out.The resistance tests of models with three dif ferent masses(127.4 kg,159.5 kg,202.9 kg)are conducted for the Froude number in the range of 0.761≤Fn≤1.925.The results of resistance measured by towing tank imply that the tunneled planing hull with a larger displacement has a superior resistance performance.The numerical simulation of Reynolds Average Navier Stokes(RANS)equations based on the finite volume method is performed to analyze the hull characteristics in calm water(M=159.5 kg)with two degrees of freedom(sinkage and trim).The numerical results are compared with the experimental data,which shows good agreement.Pressure distribution,wave profiles and lift forces obtained by SST k-ωand Realizable k-εturbulence models are compared and discussed.Finally,the local fluid flow of streamline around the hull can be divided into four regions due to the presence of a tunnel,which is different from the behaviors of the conventional planing monohull with prismatic form.
基金supported by the Sharing and Diffusion of National R&D Outcome funded by the Korea Institute of Science and Technology Information
文摘Distributed/parallel-processing system like sun grid engine(SGE) that utilizes multiple nodes/cores is proposed for the faster processing of large sized satellite image data. After verification, distributed process environment for pre-processing performance can be improved by up to 560.65% from single processing system. Through this, analysis performance in various fields can be improved, and moreover, near-real time service can be achieved in near future.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2012R1A1A4A0105777)supported by the MSIP (Ministry of Science, ICT and Future Planning), Korea, under the ITRC (Information Technology Research Center) support program (NIPA-2013-H030113-4007) supervised by the NIPA (National IT Industry Promotion Agency)
文摘A scheduling scheme is proposed to reduce execution time by means of both checkpoint sharing and task duplication under a peer-to-peer(P2P) architecture. In the scheme, the checkpoint executed by each peer(i.e., a resource) is used as an intermediate result and executed in other peers via its duplication and transmission. As the checkpoint is close to a final result, the reduction of execution time for each task becomes higher, leading to reducing turnaround time. To evaluate the performance of our scheduling scheme in terms of transmission cost and execution time, an analytical model with an embedded Markov chain is presented. We also conduct simulations with a failure rate of tasks and compare the performance of our scheduling scheme with that of the existing scheme based on client-server architecture. Performance results show that our scheduling scheme is superior to the existing scheme with respect to the reduction of execution time and turnaround time.
基金Projects(2020JJ4578, 2019JJ50604) supported by the Natural Science Foundation of Hunan Province,ChinaProject(19A499) supported by the Key Program of the Scientific Research Foundation of the Education Department of Hunan Province,China。
文摘For non-quenchable dual-phase(DP)steel sheet,the warm forming process can effectively reduce the amount of springback,and the mechanical parameters that influence its elastic and inelastic recovery to decrease exhibit a strong temperature dependence,especially under cyclic loading conditions.In this paper,the monotonic and cyclic loading tests of DP980 steel sheets are conducted at the temperatures ranging from 25℃ to 500℃.The temperature-dependent flow stress,nonlinear elastic recovery,and Bauschinger effect are investigated.The results demonstrate that both the elastic modulus and Bauschinger effect show an exponential law with pre-strain,and decrease with the increase of forming temperature,while there will be an abnormal phenomenon of rebound due to the influence of dynamic strain aging effect.Meanwhile,a linear relationship between the Bauschinger effect and inelastic strain is observed at various temperatures,and the weight of the Bauschinger effect in the total strain reduces with temperature increasing,which indicates that the springback is dominated by linear elastic recovery.Furthermore,the U-draw bending tests are carried out to clarify the influence of Vickers hardness distribution and martensite size effect on the springback behavior.
基金Project(51238008)supported by the National Natural Science Foundation of ChinaProject(CXZZ13_0116)supported by the Fundamental Research Funds for the Central Universities of ChinaProject(YBJJ1344)supported by the Scientific Research Foundations of Graduate School of Southeast University,China
文摘A good understanding of pedestrian movement in the transfer corridor is vital for the planning and design of the station,especially for efficiency and safety.A multi-force vector grid model was presented to simulate the movement of bidirectional pedestrian flow based on cellular automata and forces between pedestrians.The model improves rule-based characteristics of cellular automata,details forces between pedestrians and solves pedestrian collisions by a several-step updating method to simulate pedestrian movements.Two general scenarios in corridor were simulated.One is bidirectional pedestrian flow simulation with isolation facility,and the other is bidirectional pedestrian flow simulation without isolation facility,where there exists disturbance in the middle.Through simulation,some facts can be seen that pedestrians in the case with isolation facility have the largest speed and pedestrians in the case without isolation facility have the smallest speed; pedestrians in the case of unidirectional flow have the largest volume and pedestrians in the case of without isolation facility have the smallest volume.
