一些特殊子群对有限群可解性的影响

讨论了有限群的某些特殊子群与有限群可解性的关系,得到有限群可解的一些充分条件.     

含趋势项时间序列持久性变点监测

针对核加权方差比率统计量不是监测从非平稳向平稳变化持久性变点一致方法的问题，通过引进一个窗宽参数，提出了一种滑动核加权方差比率统计量来监测含趋势项时间序列从非平稳向平稳变化的持久性.在非平稳原假设下给出了监测统计量的极限分布和经验临界值表，在备择假设下证明了新方法的一致性.模拟结果表明新方法具有比原方法更高的势和更短的平均运行长度，最后通过分析人民币与美元汇率数据进一步说明了该方法的有效性.     

C－正规、M－正规与有限群的结构

本文利用C－正规子群及M－正规子群的性质刻划有限群的可解性、P－闭性、幂零性。     

关于G/G/1排队模型中排队长度的积分

考虑了一个具有中度正则变化服务时间的G/G/1模型.假设Q(t)是排队长度,则在忙期[0,l]上,Q(t)下方所扫过的面积也具有中度正则变化的性质.     

A NAM Representation Method for Data Compression of Binary Images

A representation method using the non-symmetry and anti-packing model (NAM) for data compression of binary images is presented.The NAM representation algorithm is compared with the popular linear quadtree and run length encoding algorithms.Theoretical and experimental results show that the algorithm has a higher compression ratio for both lossy and lossless cases of binary images and better reconstructed quality for the lossy case.     

弧长公式成立的充要条件

连续曲线不一定可求长，连续曲线可求长当且仅当它的参数表示是有界变差的，但弧长未必能用公式表达，利用勒贝格积分的基本理论证明绝对连续是弧长可用公式计算的充要条件。     

非正规子群的共轭类类数为3的p^aq^br^c阶群

给出了非正规子群的共轭类类数为3的p^aq^br^c阶群的分类。     

须丛曲线理论研究

提出了一种测量纤维长度的新制样方法——纤维条梳夹取样法,理论研究了以此法制取试样(即须丛)的纤维长度分布规律,建立了须丛曲线(纤维根数随长度变化规律)理论方程,获得了原样品长度质量分布与须丛曲线的数学关系,并推导出由须丛曲线计算原样品长度质量分布参数(平均长度、主体长度、品质长度、变异系数)的计算公式.     

The atyid shrimp (Crustacea: Decapoda: Atyidae) rostrum: phylogeny versus adaptation,taxonomy versus trophic ecology

Cave shrimps of the subgenus Troglocaris (Atyidae), exhibit high variability in rostral length and dentition. In shrimp populations that co-occur with the amphibian predator Proteus anguinus, longer rostra armed with more numerous teeth are recorded. These shrimps are also larger than those living in a presumably Proteus-free environment. Discrepancies between molecularly established phylogenetic relationships and distributions of rostral length, as well as body size, directed our search towards possible environmental influences. These discrepancies suggest that rostral shape is not a reliable taxonomic character in some generic and many specific diagnoses in Atyidae. We discuss some taxonomic consequences of sexual and ontogenetic rostral differences with regard to the molecular phylogenetic tree. In preliminary laboratory observations, no frontal attack by Proteus was successful on shrimps with long rostra. Proteus also needed more time to swallow shrimps with long rostra.