Link-up between farmers and supermarket is a new move adopted actively by the current government, conducive to consumers, farmers and circulation enterprises. At present, link-up between farmers and supermarket is lau...Link-up between farmers and supermarket is a new move adopted actively by the current government, conducive to consumers, farmers and circulation enterprises. At present, link-up between farmers and supermarket is launched in China's 15 provinces and cities, which will set off the revolution in the field of agricultural circulation. Based on the current situation of link-up between farmers and supermarket and the existing problems, we put forth the following recommendations: promoting the quality of farmers' cooperative organizations; establishing the logistics center of fresh agricultural products; using economies of scale to reduce the fresh logistics costs; improving the operation and management level of fresh agricultural products in supermarket.展开更多
Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links wer...Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links were designed using steel grades with yield points ranging from high to low strengths. The objectives of the numerical analyses were to further investigate the non-linear behavior and to correlate the numerical results with experimental observations. Elasto-plastic as well as cyclic stress-strain material properties were incorporated to study the influence of material behavior on the overall shear link response. Non-linear monotonie analyses of the shear links incorporating the cyclic stress-strain steel properties resulted in similar trends in the response as the backbone curves recorded from the physical experiments. The numerical models of built-up shear links utilizing structural grade steels closely correlated to the experimentally recorded shear strength. Models utilizing low yield point steels overestimated the shear strength, which was caused by the characteristics of cyclic behavior of those steels. The detailed numerical models also allowed for investigation of the plastic strain demands on the different components of the link. It was shown that finite element models combined with appropriate stress-strain relationship may be used with confidence to check the design of shear links of different steel grades and sectional geometries.展开更多
Traditional cellular network requires that a user equipment(UE) should associate to the same base station(BS) in both the downlink(DL) and the uplink(UL). Based on dual connectivity(DC) introduced in LTE-Advanced R12,...Traditional cellular network requires that a user equipment(UE) should associate to the same base station(BS) in both the downlink(DL) and the uplink(UL). Based on dual connectivity(DC) introduced in LTE-Advanced R12, DL/UL decouple access scheme has been proposed, which is especially suitable for heterogeneous networks(Het Nets). This paper is the pioneer to take the DL/UL decouple access scheme into consideration and develop a novel resource allocation algorithm in a two-tier Het Net to improve the total system throughput in the UL and ease the load imbalance between macro base stations(MBSs) and pico base stations(PBSs). A model is formulated as a nonlinear integer programming, and the proposed algorithm is a sub-optimal algorithm based on the graph theory. First, an undirected and weighted interference graph is obtained. Next, the users are grouped to let users with large mutual interferences to be assigned to different clusters. Then, the users in different clusters are allocated to different resource blocks(RBs) by using the Hungarian algorithm. Simulation results show that the proposed algorithm can provide great promotions for both the total system throughput and the average cell edge user throughput and successfully ease the load imbalance between MBSs and PBSs.展开更多
Numerically analyzed is the transmission performance of the optical millimeter(mm)-wave generated by frequency up-conversion via a phase modulator along the dispersive fiber.60 GHz mm-wave sub-carrier(SC)signals can b...Numerically analyzed is the transmission performance of the optical millimeter(mm)-wave generated by frequency up-conversion via a phase modulator along the dispersive fiber.60 GHz mm-wave sub-carrier(SC)signals can be obtained after fiber transmission,simultaneously,the phase-modulated signals can be converted to the intensity-modulated ones.The numerical results show that the optical mm-wave at fading loops has better performance,and the eye diagram still keeps open when optical mm-wave signal is transmitted over 98 km.展开更多
基金Supported by Humanities and Social Sciences Youth Project of theMinistry of Education in 2010 (10YJC790234)
文摘Link-up between farmers and supermarket is a new move adopted actively by the current government, conducive to consumers, farmers and circulation enterprises. At present, link-up between farmers and supermarket is launched in China's 15 provinces and cities, which will set off the revolution in the field of agricultural circulation. Based on the current situation of link-up between farmers and supermarket and the existing problems, we put forth the following recommendations: promoting the quality of farmers' cooperative organizations; establishing the logistics center of fresh agricultural products; using economies of scale to reduce the fresh logistics costs; improving the operation and management level of fresh agricultural products in supermarket.
基金the Federal Highway Administration through the Highway Project at the Multidisciplinary Center for Earthquake Engineering Researchthe toll bridge retrofit program of the California Department of Transportation through the University of California,San Diego
文摘Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links were designed using steel grades with yield points ranging from high to low strengths. The objectives of the numerical analyses were to further investigate the non-linear behavior and to correlate the numerical results with experimental observations. Elasto-plastic as well as cyclic stress-strain material properties were incorporated to study the influence of material behavior on the overall shear link response. Non-linear monotonie analyses of the shear links incorporating the cyclic stress-strain steel properties resulted in similar trends in the response as the backbone curves recorded from the physical experiments. The numerical models of built-up shear links utilizing structural grade steels closely correlated to the experimentally recorded shear strength. Models utilizing low yield point steels overestimated the shear strength, which was caused by the characteristics of cyclic behavior of those steels. The detailed numerical models also allowed for investigation of the plastic strain demands on the different components of the link. It was shown that finite element models combined with appropriate stress-strain relationship may be used with confidence to check the design of shear links of different steel grades and sectional geometries.
基金supported by the National Natural Science Foundation General Program of China under Grant No.61171110the National Basic Research Program of China under Grant No.2013CB329003
文摘Traditional cellular network requires that a user equipment(UE) should associate to the same base station(BS) in both the downlink(DL) and the uplink(UL). Based on dual connectivity(DC) introduced in LTE-Advanced R12, DL/UL decouple access scheme has been proposed, which is especially suitable for heterogeneous networks(Het Nets). This paper is the pioneer to take the DL/UL decouple access scheme into consideration and develop a novel resource allocation algorithm in a two-tier Het Net to improve the total system throughput in the UL and ease the load imbalance between macro base stations(MBSs) and pico base stations(PBSs). A model is formulated as a nonlinear integer programming, and the proposed algorithm is a sub-optimal algorithm based on the graph theory. First, an undirected and weighted interference graph is obtained. Next, the users are grouped to let users with large mutual interferences to be assigned to different clusters. Then, the users in different clusters are allocated to different resource blocks(RBs) by using the Hungarian algorithm. Simulation results show that the proposed algorithm can provide great promotions for both the total system throughput and the average cell edge user throughput and successfully ease the load imbalance between MBSs and PBSs.
基金Dr Start-up Fund of Wuyi University,National Natural Science Foundation of China(60677004)
文摘Numerically analyzed is the transmission performance of the optical millimeter(mm)-wave generated by frequency up-conversion via a phase modulator along the dispersive fiber.60 GHz mm-wave sub-carrier(SC)signals can be obtained after fiber transmission,simultaneously,the phase-modulated signals can be converted to the intensity-modulated ones.The numerical results show that the optical mm-wave at fading loops has better performance,and the eye diagram still keeps open when optical mm-wave signal is transmitted over 98 km.
