Wireless sensor network is becoming more and more popular in recent years, but energy- constrained characteristic of sensor nodes is one of the critical issues that we must consider in system design. In this paper, a ...Wireless sensor network is becoming more and more popular in recent years, but energy- constrained characteristic of sensor nodes is one of the critical issues that we must consider in system design. In this paper, a cluster-based virtual VBLAST transmission scheme is proposed to achieve energy savings for energy-constrained wireless sensor networks. In the proposed scheme, instead of using cluster member as cooperative nodes, multiple cluster heads cooperate to form virtual antenna array so that V-BLAST based virtual MIMO transmission can be implemented. Based on the communication energy consumption model, a way to optimize the parameters for the scheme is given. In addition, detailed simulation is performed to evaluate the performance of the proposed scheme for both densely and sparsely deployed sensor networks. Theoretical analysis and simulation results verify the energy efficiency of the proposed scheme.展开更多
In order to guarantee the wireless multicast throughput at a minimum cost, we propose a layered hypergraph high-dimension clustering algorithm (LayerHC) considering the channels and statistical locations of mobile mem...In order to guarantee the wireless multicast throughput at a minimum cost, we propose a layered hypergraph high-dimension clustering algorithm (LayerHC) considering the channels and statistical locations of mobile members. The algorithm can achieve a minimum multicast spanning tree to obtain a minimum number of relays and effective cooperative areas with low computational complexity.展开更多
The food industry is evolving more towards new forms of organization much more complex and characterized by a greater degree of coordination, whether in the form of vertical integration of explicit or implicit contrac...The food industry is evolving more towards new forms of organization much more complex and characterized by a greater degree of coordination, whether in the form of vertical integration of explicit or implicit contracts between players of different levels of the industry. Therefore, the aim of this work is the search for mechanisms that can provide value to the production phase to better increase competitiveness of the sector. For the first time, in fact, discussion about food chains have as reference a recognized legal entity, which is the integrated projects of food chain as a result of actions of agricultural policy at community, national and regional levels. The methodology is related to two steps： the administration of questionnaires to the three companies participating in food chain partnerships that have proposed a draft of integrated design of food chain in response to the notice of the Apulia region for the submission of the integrated projects of the food chain; and a cluster analysis in the wine sector of the Italian regions. The results showed, thanks to Network Analysis, the importance for the chain development of relationships formed by market relations and cooperation relations （formal and informal） and the need for more actions for the enhancement of products by research and development activities.展开更多
文摘Wireless sensor network is becoming more and more popular in recent years, but energy- constrained characteristic of sensor nodes is one of the critical issues that we must consider in system design. In this paper, a cluster-based virtual VBLAST transmission scheme is proposed to achieve energy savings for energy-constrained wireless sensor networks. In the proposed scheme, instead of using cluster member as cooperative nodes, multiple cluster heads cooperate to form virtual antenna array so that V-BLAST based virtual MIMO transmission can be implemented. Based on the communication energy consumption model, a way to optimize the parameters for the scheme is given. In addition, detailed simulation is performed to evaluate the performance of the proposed scheme for both densely and sparsely deployed sensor networks. Theoretical analysis and simulation results verify the energy efficiency of the proposed scheme.
基金Acknowledgements This work was supported by Natural Science Foundation of Beijing under Grant No. 4102041.
文摘In order to guarantee the wireless multicast throughput at a minimum cost, we propose a layered hypergraph high-dimension clustering algorithm (LayerHC) considering the channels and statistical locations of mobile members. The algorithm can achieve a minimum multicast spanning tree to obtain a minimum number of relays and effective cooperative areas with low computational complexity.
文摘The food industry is evolving more towards new forms of organization much more complex and characterized by a greater degree of coordination, whether in the form of vertical integration of explicit or implicit contracts between players of different levels of the industry. Therefore, the aim of this work is the search for mechanisms that can provide value to the production phase to better increase competitiveness of the sector. For the first time, in fact, discussion about food chains have as reference a recognized legal entity, which is the integrated projects of food chain as a result of actions of agricultural policy at community, national and regional levels. The methodology is related to two steps： the administration of questionnaires to the three companies participating in food chain partnerships that have proposed a draft of integrated design of food chain in response to the notice of the Apulia region for the submission of the integrated projects of the food chain; and a cluster analysis in the wine sector of the Italian regions. The results showed, thanks to Network Analysis, the importance for the chain development of relationships formed by market relations and cooperation relations （formal and informal） and the need for more actions for the enhancement of products by research and development activities.
