排序方式: 共有12条查询结果,搜索用时 31 毫秒
1.
为了提高部分传输序列(PTS)方法在正交频分复用(OFDM)系统中降低峰均功率比(PAPR)的能力,研究了PTS方法中的子块划分问题.通过PTS的自相关函数(ACFs)和备选信号的互相关函数(CCFs),将子块划分和降低PAPR的能力相关联.这里用Q表示ACFs的均方幅度的方差.研究发现Q值越小PTS方法所能达到的PAPR性能越好,并以此作为子块划分的设计准则.依据这一准则,对4种常见的分块方法做了比较并提出一种有效的子块划分策略.比较结果表明具有良好结构性的子块划分方法在具有低运算复杂度的同时ACFs的均方幅度方差较大,因此PAPR性能不佳.新策略可以看作是在PAPR性能和运算复杂度间所做的一种折中.仿真结果表明该策略可以在相对低的复杂度的条件下达到最优性能,同时也不会增加附加信息. 相似文献
2.
3.
Partial transmit sequence(PTS)is a promising technique for peak-to-average power ratio(PAPR)reduction in orthogonal frequency division multiplexing(OFDM).While in optimal PTS,an exhaustive search for all combinations of phase factor sequences is required,this results in huge computation.In this paper,by introducing the orthogonal design,a phase factor sequences algorithm is proposed.The algorithm uses orthogonal table to gencrate phase factor sequences,and the regular PAPR computation result is then followed by the parameter estimation.The simulation result shows that the proposed algorithm reduces the computation notably and obtains a good PAPR performance approaching the optimal PTS. 相似文献
4.
笔者提出了一种两阶段减少峰均功率比的方法。我们分析了本方法的计算复杂度,并通过多次仿真实现了结果。在降低复杂度的情况下,我们可降低与选择映射相同的峰均功率比,并优于部分传输序列。 相似文献
5.
人参二醇组皂甙、三醇组皂甙对游泳训练大鼠细胞免疫的影响 总被引:3,自引:1,他引:2
目的:观察人参二醇组皂甙(PDS)、三醇组皂甙(PTS)对进行长期游泳训练的动物模型大鼠的免疫调节效应。方法:免疫检测指标:淋巴细胞转化实验与胸腺细胞自发增殖反应。结果:PDS、PTS可以遏制长期游泳训练大鼠胸腺细胞自发增殖反应指标下降的趋势,对运动后胸腺细胞自发增殖反应的恢复有促进效应。结论:PDS、PTS利于运动后机体细胞免疫功能的恢复。 相似文献
6.
张淼 《和田师范专科学校学报》2009,28(5):31-32
目的:研究警校大学新生心理健康水平与性别、独生子女相关因素之间的关系。方法采用大学生人格问卷(UPI)对986名新生进行心理健康状况调查。结果:在性别方面,女生的一类人数所占比例高于男生:在独生子女与非独生子女比较时,独生子女的一类人数所占比例高于非独生子女。结论:在警校大学新生中女生的心理健康水平低于男生,独生子女的心理健康水平低于非独生子女。 相似文献
7.
8.
Wang JY Wu XY Zhang Z Du XF Chai RY Liu XH Mao XQ Qiu HP Wang YL Lin FC Sun GC 《Journal of Zhejiang University. Science. B》2008,9(10):802-810
The peroxisomal matrix proteins involved in many important biological metabolism pathways in eukaryotic cells are encoded by nucleal genes, synthesized in the cytoplasm and then transported into the organelles. Targeting and import of these proteins depend on their two peroxisomal targeting signals (PTS1 and PTS2) in sequence as we have known so far. The vectors of the fluorescent fusions with PTS, i.e., green fluorescence protein (GFP)-PTSI, GFP-PTS2 and red fluorescence protein (RFP)-PTS1, were constructed and introduced into Magnaporthe oryzae Guy11 cells. Transformants containing these fusions emitted fluorescence in a punctate pattern, and the locations of the red and green fluorescence overlapped exactly in RFP-PTS1 and GFP-PTS2 co-transformed strains. These data indicated that both PTS 1 and PTS2 fusions were imported into peroxisomes. A probable higher efficiency of PTSI machinery was revealed by comparing the fluorescence backgrounds in GFP-PTS1 and GFP-PTS2 transformants. By introducing both RFP-PTS1 and GFP-PTS2 into △mgpex6 mutants, the involvement of MGPEX6 gene in both PTS1 and PTS2 pathways was proved. In addition, using these transformants, the inducement of peroxisomes and the dynamic of peroxisomal number during the pre-penetration processes were investigated as well. In summary, by the localization and co-localization of PTSI and PTS2, we provided a useful tool to evaluate the biological roles of the peroxisomes and the related genes. 相似文献
9.
陈全静 《荆门职业技术学院学报》2010,25(4):46-49
先秦时期介词框架“PP上”大多位于谓语动词后,但现代汉语中的“PP上”基本上是位于谓语动词前的,这种变化的过程怎样,是什么原因致使“PP上”的前移,文章试图在大量历时语料的基础上描写“PP上”前移的过程并力求给予合理的解释。 相似文献
10.
针对OFDM系统峰均比PAPR过大而限制其应用的缺点,对比分析了目前优化PAPR的传统PTS(部分传输序列法)算法以及优化的PTS算法的性能与计算复杂度,在此基础上提出分组优化PTS算法,在性能与计算复杂度上有良好平衡。最后对各种算法列表对比优劣,对今后的算法研究提供一定的参考价值。 相似文献