Productivity potentials of upland rice landraces (URLs) are continuously compromised by scanty water supply due to competing priorities for irrigations and fluctuations in agro-ecological conditions peculiar to low-in...Productivity potentials of upland rice landraces (URLs) are continuously compromised by scanty water supply due to competing priorities for irrigations and fluctuations in agro-ecological conditions peculiar to low-input farming systems. A growing demand for rice amidst decline in productive agricultural areas plunges into an urgent contribution of marginal areas critical in attaining food sufficiency among Filipino households. Agronomic performances of URLs locally found in Catanduanes province, Philippines were evaluated in a replicated trial utilizing three URLs: Kamanang [1], Kadari [2] and Bulaw [3]. The experimental set-up was closely monitored for consistent dry moisture content and zero fertilizer application. Results were significant for traditional upland landraces: Kamanang and Kadari, scored in terms of higher germination rate, increment plant height and the number of tillers during the vegetative stage. Leaf color gradations, although statistically not significant across cultivars, were suggestive of varying adaptive performance between traditional cultivars subjected to low-input system. Putative low-input responsive lines indicated by the higher survival percentage and overall agronomic responses were selected from the study site. Screened lines took part of the advance population which would be potentially able to tolerate poor soil conditions (i.e. poor storehouse of water and nutrients) especially in areas with edaphological constraints and changing rainfall distribution pattern. The development of putative drought tolerant lines among URLs forms the most economical solution implicated to areas with limited access to agricultural interventions.展开更多
针对低空经济通信中导频受限的多输入多输出正交频分复用(Multiple Input and Multiple Output Orthogonal Frequency Division Multiplexing,MIMO-OFDM)存在的信道估计精度低的问题,提出一种适用于低空多径环境的MIMO-OFDM信道估计新...针对低空经济通信中导频受限的多输入多输出正交频分复用(Multiple Input and Multiple Output Orthogonal Frequency Division Multiplexing,MIMO-OFDM)存在的信道估计精度低的问题,提出一种适用于低空多径环境的MIMO-OFDM信道估计新方法。在时频资源平面上,该方法利用信道平滑特征和导频信道系数在子载波和符号维度的关联,根据导频点生成初始的Voronoi图,然后基于插值数据点更新Voronoi图,并将两个Voronoi图叠加。更新Voronoi图中插值数据点所属的Voronoi小区域被初始Voronoi图划分为多块,根据每块面积计算权重,再将多个相邻导频处的信道估计值加权求和,从而得到对应插值数据点的信道估计值。仿真结果表明,与线性插值方法相比,所提方法使得信道估计归一化均方误差降低了50%,误比特率性能提升了1.6 dB。展开更多
文摘Productivity potentials of upland rice landraces (URLs) are continuously compromised by scanty water supply due to competing priorities for irrigations and fluctuations in agro-ecological conditions peculiar to low-input farming systems. A growing demand for rice amidst decline in productive agricultural areas plunges into an urgent contribution of marginal areas critical in attaining food sufficiency among Filipino households. Agronomic performances of URLs locally found in Catanduanes province, Philippines were evaluated in a replicated trial utilizing three URLs: Kamanang [1], Kadari [2] and Bulaw [3]. The experimental set-up was closely monitored for consistent dry moisture content and zero fertilizer application. Results were significant for traditional upland landraces: Kamanang and Kadari, scored in terms of higher germination rate, increment plant height and the number of tillers during the vegetative stage. Leaf color gradations, although statistically not significant across cultivars, were suggestive of varying adaptive performance between traditional cultivars subjected to low-input system. Putative low-input responsive lines indicated by the higher survival percentage and overall agronomic responses were selected from the study site. Screened lines took part of the advance population which would be potentially able to tolerate poor soil conditions (i.e. poor storehouse of water and nutrients) especially in areas with edaphological constraints and changing rainfall distribution pattern. The development of putative drought tolerant lines among URLs forms the most economical solution implicated to areas with limited access to agricultural interventions.
文摘针对低空经济通信中导频受限的多输入多输出正交频分复用(Multiple Input and Multiple Output Orthogonal Frequency Division Multiplexing,MIMO-OFDM)存在的信道估计精度低的问题,提出一种适用于低空多径环境的MIMO-OFDM信道估计新方法。在时频资源平面上,该方法利用信道平滑特征和导频信道系数在子载波和符号维度的关联,根据导频点生成初始的Voronoi图,然后基于插值数据点更新Voronoi图,并将两个Voronoi图叠加。更新Voronoi图中插值数据点所属的Voronoi小区域被初始Voronoi图划分为多块,根据每块面积计算权重,再将多个相邻导频处的信道估计值加权求和,从而得到对应插值数据点的信道估计值。仿真结果表明,与线性插值方法相比,所提方法使得信道估计归一化均方误差降低了50%,误比特率性能提升了1.6 dB。
