توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقالههای نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده میشوند.
۱A Comparative Study on the Growth and Nutrient Uptake Characteristics of Fifteen Wetland Species in Taihu Lake Region of China
اطلاعات انتشار: International Journal Of Environmental Research، پنجم،شماره۲، Spring ۲۰۱۱، سال ۰
تعداد صفحات: ۱۰
Fifteen kinds of local wetland plants in Taihu Lake region of China were investigated on their respective growth conditions, biomass allocations and nutrient uptake capacities. The test plants were cultured in 3 L nutrient solutions for 28 days with NH4 +–N, NO3 ––N and P concentrations of 38.5, 132.8 and 10 mg\L, respectively. Mean species total biomass ranged from 1.2–21.6 g\plant with above\below ground ratios (AG:BG) between 1.7–5.5. Mean NH4 +–N, NO3 ––N and P uptake rates ranged from 3.7–14.3 mg\day (8.0–49.4 % of NH4 +–N supplied), 17.8–59.4 mg\day (17.8–59.6 %) of NO3 ––N supplied and 1.71–4.61 mg \day (24.1–61.5 % of P supplied), respectively. Plant tissue N and P concentrations ranged between 28.2–606.1 mg N \plant and 4.1–53.1 mg P\plant, with AG:BG ratio between 1.7–7.0 and 1.6–4.6, respectively. The accumulation of N and P in plant tissues was significantly correlated with plant biomass and root surface area. Among the different species, C. generalis, T. latifolia, T. dealbata and L. salicaria were better than the other plants in above– and below–ground biomass, root surface area, nutrient uptake and storage rates. T. dealbata and L. salicaria were more suitable for year–round application in this area due to their tolerance of coldness.
۲Efficient Packet Replication Control for a Geographical Routing Protocol in Sparse Vehicular Delay Tolerant Networks
اطلاعات انتشار: Scientia Iranica، بيست و دوم،شماره۴، ۲۰۱۵، سال ۰
تعداد صفحات: ۱۷
To date, many vehicular ad hoc network unicast routing protocols have been proposed to support efficient packet transmission between vehicles in urban environments. However, when there is insufficient vehicle density during non–rush hour times, the vehicular ad hoc network is often intermittently connected. These unicast routing protocols therefore perform poorly when forwarding packets over this vehicular disruption tolerant network. This paper adopts the controlled replication approach in a proposed IG–Ferry routing protocol to spray a limited number of packet copies, denoted by the packet token values, to relay vehicles in a vehicular disruption tolerant network. We then identify three kinds of relay vehicles, i.e., direct buses, non–direct buses and private cars, according to their travel itineraries. Based on the proposed delay evaluation function for the three types of intermediate vehicles, the IG–Ferry packet spraying mechanism, instead of the traditional binary spraying one, can efficiently spray appropriate packet tokens to vehicles. Finally, intensive NS2 simulations are conducted using the realistic Shanghai city vehicle traffic trace, IEEE 802.11p protocol with EDCA and Nakagami radio propagation model to show that IG–Ferry outperforms three well–known VDTN routing protocols, in terms of average packet delivery ratios, end–to–end transmission delays and packet replication overheads with respect to various combinations of five communication parameters.
نمایش نتایج ۱ تا ۲ از میان ۲ نتیجه