Recently a number of multicast routing protocols for ad hoc networks have been proposed, however, most of them do not provide proper tradeoffs between effectiveness, efficiency and scalability. In this paper, a novel ...Recently a number of multicast routing protocols for ad hoc networks have been proposed, however, most of them do not provide proper tradeoffs between effectiveness, efficiency and scalability. In this paper, a novel multicast routing protocol is presented for ad hoc networks. The protocol, termed as dynamic-ring-based multicast routing protocol (DRMR), uses the concept of dynamic ring whose radius can be adjusted dynamically and DRMR configures this type of ring for all group member nodes. According to the principle of zone routing, two nodes whose rings overlap can create route to each other, thus, when the ring graph composed of all rings is connected, each member node has one or more routes to others. DRMR uses the method of expanding ring search (ERS) to maintain the connected ring graph, and also can decrease the radius of the ring to reduce the overhead. The performances of DRMR were simulated and evaluated with NS2, and results show that DRMR has a high data packet delivery ratio, low control overhead and good scalability.展开更多
Abstract: Cell death is a common event in all types of plant organisms. Understanding the phenomenon of programmed cell death (PCD) is an important area of research for plant scientists because of its role in senescen...Abstract: Cell death is a common event in all types of plant organisms. Understanding the phenomenon of programmed cell death (PCD) is an important area of research for plant scientists because of its role in senescence and the post-harvest quality of ornamentals, fruits, and vegetables. In the present paper, PCD in relation to petal senescence in ornamental plants is reviewed. Morphological, anatomical, physiological, and biochemical changes that are related to PCD in petals, such as water content, sink-source relationships, hormones, genes, and signal transduction pathways, are discussed. Several approaches to improving the quality of post-harvest ornamentals are reviewed and some prospects for future research are given.展开更多
Ad Hoc网络是一个无基础结构的无线网络，由于架构这种网络非常方便，因此它可广泛应用于灾难救助、战场指挥、临时会议等场合。这些应用通常都有一个共同的特征，就是一到多或是多到多的数据传输。因此，组播路由协议在Ad Hoc网络中具...Ad Hoc网络是一个无基础结构的无线网络，由于架构这种网络非常方便，因此它可广泛应用于灾难救助、战场指挥、临时会议等场合。这些应用通常都有一个共同的特征，就是一到多或是多到多的数据传输。因此，组播路由协议在Ad Hoc网络中具有非常重要的作用。近几年。展开更多
文摘Recently a number of multicast routing protocols for ad hoc networks have been proposed, however, most of them do not provide proper tradeoffs between effectiveness, efficiency and scalability. In this paper, a novel multicast routing protocol is presented for ad hoc networks. The protocol, termed as dynamic-ring-based multicast routing protocol (DRMR), uses the concept of dynamic ring whose radius can be adjusted dynamically and DRMR configures this type of ring for all group member nodes. According to the principle of zone routing, two nodes whose rings overlap can create route to each other, thus, when the ring graph composed of all rings is connected, each member node has one or more routes to others. DRMR uses the method of expanding ring search (ERS) to maintain the connected ring graph, and also can decrease the radius of the ring to reduce the overhead. The performances of DRMR were simulated and evaluated with NS2, and results show that DRMR has a high data packet delivery ratio, low control overhead and good scalability.
文摘Abstract: Cell death is a common event in all types of plant organisms. Understanding the phenomenon of programmed cell death (PCD) is an important area of research for plant scientists because of its role in senescence and the post-harvest quality of ornamentals, fruits, and vegetables. In the present paper, PCD in relation to petal senescence in ornamental plants is reviewed. Morphological, anatomical, physiological, and biochemical changes that are related to PCD in petals, such as water content, sink-source relationships, hormones, genes, and signal transduction pathways, are discussed. Several approaches to improving the quality of post-harvest ornamentals are reviewed and some prospects for future research are given.
