The essential requirements of the end-effector of large space manipulator are capabilities of misalignment tolerance and soft capture.According to these requirements,an end-effector prototype combining the tendon-shea...The essential requirements of the end-effector of large space manipulator are capabilities of misalignment tolerance and soft capture.According to these requirements,an end-effector prototype combining the tendon-sheath transmission system with steel cable snaring mechanism was manufactured.An analysis method based on the coordinate transformation and the projection of key points of the mechanical interface was proposed,and it was a guideline of the end-effector design.Furthermore,the tendon-sheath transmission system was employed in the capture subassembly to reduce the inertia of the capture mechanism and enlarge the capture space.The capabilities of misalignment tolerance and soft capture were validated through the dynamic simulation in ADAMS software.The results of the capture simulation and experiment show that the end-effector has outstanding capabilities of misalignment tolerance and soft capture.The translation misalignments in radial directions are±100 mm,and angular misalignments about pitch and yaw are±15°.展开更多
ABM: To introduce the basic methods of gray relational analysis (GRA) and to illustrate its applications in gastroenterology. METHODS: With the essential formulae of GRA and several typically practical examples, the p...ABM: To introduce the basic methods of gray relational analysis (GRA) and to illustrate its applications in gastroenterology. METHODS: With the essential formulae of GRA and several typically practical examples, the procedure of GRA was introduced. Examples were drawn from the gastroenterological studies. Thus the trait of GRA could be demonstrated. RESULTS: The superiority of GRA in gastroenterological study was proved by the examples. CONCLUSION: GRA can be applied mechanically or flexibly in gastroenterology.展开更多
With the increase of network complexity,the flexibility of network control and management becomes a nontrivial problem.Both Software Defined Network(SDN) and Autonomic Network technologies are sophisticated technologi...With the increase of network complexity,the flexibility of network control and management becomes a nontrivial problem.Both Software Defined Network(SDN) and Autonomic Network technologies are sophisticated technologies for the network control and management.These two technologies could be combined together to construct a software defined self-managing solution for the future network.An autonomic QoS management mechanism in Software Defined Network(AQSDN) is proposed in this paper.In AQSDN,the various QoS features can be configured autonomically in an OpenFlow switch through extending the OpenFlow and OF-Config protocols.Based on AQSDN,a novel packet context-aware QoS model(PCaQoS) is also introduced for improving the network QoS.PCaQoS takes packet context into account when packet is marked and managed into forwarding queues.The implementation of a video application's prototype which evaluates the self-configuration feature of the AQSDN and the enhancement ability of the PCaQoS is presented in order to validate this design.展开更多
The low-cost,self-configuration capability and "plug-and-play" feature of Ethernet establishes its dominant position in the local area networks(LAN).However,it is hard to extend to large scale because of the...The low-cost,self-configuration capability and "plug-and-play" feature of Ethernet establishes its dominant position in the local area networks(LAN).However,it is hard to extend to large scale because of the legacy broadcast-based service discovery mechanism.Therefore,to solve this problem,a new split network architecture named Software-Defined Networking(SDN) is introduced in this paper,and a novel floodless service discovery mechanism(FSDM)for SDN is designed.For the FSDM,the widespread broadcast messages for Dynamic Host Configuration Protocol(DHCP) and Address Resolution Protocol(ARP) are considered especially,respectively.Then the DHCP relay and ARP proxy are proposed to handle DHCP broadcast messages and ARP broadcast messages,respectively.The proposed FSDM in this paper can eliminate flooding completely,reserve the autoconfiguration characteristics.Particularly,there is no need to change the existing hardware,software and protocols of hosts for the proposed scheme.Finally,the simulation results are demonstrated to show that our proposed model allows redundant links existed in network and has the property of scalability,which can significantly reduce network traffic in data plane and control traffic in control plane,and decrease the overhead of control plane.展开更多
Based on the characteristics of the strong volatility of physical property in vertical direction, high gas content, high resource abundance and large exploitation potentiality of coal reservoir in Bide-Santang basin o...Based on the characteristics of the strong volatility of physical property in vertical direction, high gas content, high resource abundance and large exploitation potentiality of coal reservoir in Bide-Santang basin of Zhina coal field, we study the generation mechanism of interlayer interference, propagation rules of reservoir pressure drop and influencing factors of gas productivity in CBM multi-seam drainage in the paper. On the basis of the actual production data of X-2 well of Zhucang syncline in Bide-Santang basin,by simulating the gas production process of a CBM well under the condition of multiple seam with COMET3 numerical simulation software, we analyze the influencing factors of gas productivity during the process of multi-seam drainage, and illuminate the interlayer interference mechanism of multiseam drainage. The results show that permeability, reservoir pressure gradient, critical desorption pressure and fluid supply capacity of stratum have great influence on gas productivity of multi-seam drainage while coal thickness has little influence on it. Permeability, reservoir pressure gradient and fluid supply capacity of stratum affect the propagation velocity of reservoir pressure drop and thereby affect the final gas productivity. Moreover, the influence of critical desorption pressure on gas productivity of multiseam drainage is reflected in the gas breakthrough time and effective desorption area.展开更多
Although the modeling technologies for open robot controllers have been discussed widely, not much literature is devoted to the actual general modeling principles and strategies. The reason is that many researches foc...Although the modeling technologies for open robot controllers have been discussed widely, not much literature is devoted to the actual general modeling principles and strategies. The reason is that many researches focus on specific application fields. This paper accommodates for this lacuna and provides some general modeling principles and strategies. At last, the actual new modeling method Hierarchical Object Oriented Petri net (HOONet) which has been proved to be an effective modeling methodology, is used to illustrate the modeling strategies.展开更多
基金Project(2006AA04Z228) supported by National Hi-tech Research and Development Program of China
文摘The essential requirements of the end-effector of large space manipulator are capabilities of misalignment tolerance and soft capture.According to these requirements,an end-effector prototype combining the tendon-sheath transmission system with steel cable snaring mechanism was manufactured.An analysis method based on the coordinate transformation and the projection of key points of the mechanical interface was proposed,and it was a guideline of the end-effector design.Furthermore,the tendon-sheath transmission system was employed in the capture subassembly to reduce the inertia of the capture mechanism and enlarge the capture space.The capabilities of misalignment tolerance and soft capture were validated through the dynamic simulation in ADAMS software.The results of the capture simulation and experiment show that the end-effector has outstanding capabilities of misalignment tolerance and soft capture.The translation misalignments in radial directions are±100 mm,and angular misalignments about pitch and yaw are±15°.
基金Supported by the National Natural Science Foundation of China, No. 30271158
文摘ABM: To introduce the basic methods of gray relational analysis (GRA) and to illustrate its applications in gastroenterology. METHODS: With the essential formulae of GRA and several typically practical examples, the procedure of GRA was introduced. Examples were drawn from the gastroenterological studies. Thus the trait of GRA could be demonstrated. RESULTS: The superiority of GRA in gastroenterological study was proved by the examples. CONCLUSION: GRA can be applied mechanically or flexibly in gastroenterology.
基金This work was supported in part by the National High Technology Research and Development Program （863 Program） of China under Grant No. 2011AA01A101, No.2013AA013303, No.2013AA013301and National Natural science foundation of China No. 61370197 ＆ 61271041.
文摘With the increase of network complexity,the flexibility of network control and management becomes a nontrivial problem.Both Software Defined Network(SDN) and Autonomic Network technologies are sophisticated technologies for the network control and management.These two technologies could be combined together to construct a software defined self-managing solution for the future network.An autonomic QoS management mechanism in Software Defined Network(AQSDN) is proposed in this paper.In AQSDN,the various QoS features can be configured autonomically in an OpenFlow switch through extending the OpenFlow and OF-Config protocols.Based on AQSDN,a novel packet context-aware QoS model(PCaQoS) is also introduced for improving the network QoS.PCaQoS takes packet context into account when packet is marked and managed into forwarding queues.The implementation of a video application's prototype which evaluates the self-configuration feature of the AQSDN and the enhancement ability of the PCaQoS is presented in order to validate this design.
基金supported by the National Basic Research Program(973)of China(No.2012CB315801)the National Natural Science Fund(No.61302089,61300184)the fundamental research funds for the Central Universities(No.2013RC0113)
文摘The low-cost,self-configuration capability and "plug-and-play" feature of Ethernet establishes its dominant position in the local area networks(LAN).However,it is hard to extend to large scale because of the legacy broadcast-based service discovery mechanism.Therefore,to solve this problem,a new split network architecture named Software-Defined Networking(SDN) is introduced in this paper,and a novel floodless service discovery mechanism(FSDM)for SDN is designed.For the FSDM,the widespread broadcast messages for Dynamic Host Configuration Protocol(DHCP) and Address Resolution Protocol(ARP) are considered especially,respectively.Then the DHCP relay and ARP proxy are proposed to handle DHCP broadcast messages and ARP broadcast messages,respectively.The proposed FSDM in this paper can eliminate flooding completely,reserve the autoconfiguration characteristics.Particularly,there is no need to change the existing hardware,software and protocols of hosts for the proposed scheme.Finally,the simulation results are demonstrated to show that our proposed model allows redundant links existed in network and has the property of scalability,which can significantly reduce network traffic in data plane and control traffic in control plane,and decrease the overhead of control plane.
基金supported by the National Major Special Project of Science and Technology of China (No.2011ZX05034)the Innovation Projects of University Graduates in Jiangsu Province (No.CXLX13_948)+1 种基金the National Natural Science Foundation of China (No.41272178)the Natural Science Foundation of Hunan Province (No.2016JJ4031)
文摘Based on the characteristics of the strong volatility of physical property in vertical direction, high gas content, high resource abundance and large exploitation potentiality of coal reservoir in Bide-Santang basin of Zhina coal field, we study the generation mechanism of interlayer interference, propagation rules of reservoir pressure drop and influencing factors of gas productivity in CBM multi-seam drainage in the paper. On the basis of the actual production data of X-2 well of Zhucang syncline in Bide-Santang basin,by simulating the gas production process of a CBM well under the condition of multiple seam with COMET3 numerical simulation software, we analyze the influencing factors of gas productivity during the process of multi-seam drainage, and illuminate the interlayer interference mechanism of multiseam drainage. The results show that permeability, reservoir pressure gradient, critical desorption pressure and fluid supply capacity of stratum have great influence on gas productivity of multi-seam drainage while coal thickness has little influence on it. Permeability, reservoir pressure gradient and fluid supply capacity of stratum affect the propagation velocity of reservoir pressure drop and thereby affect the final gas productivity. Moreover, the influence of critical desorption pressure on gas productivity of multiseam drainage is reflected in the gas breakthrough time and effective desorption area.
文摘Although the modeling technologies for open robot controllers have been discussed widely, not much literature is devoted to the actual general modeling principles and strategies. The reason is that many researches focus on specific application fields. This paper accommodates for this lacuna and provides some general modeling principles and strategies. At last, the actual new modeling method Hierarchical Object Oriented Petri net (HOONet) which has been proved to be an effective modeling methodology, is used to illustrate the modeling strategies.
