In this paper, the optimization of quantizer’s segment threshold is done. The quantizer is designed on the basis of approximative spline functions. Coefficients on which we form approximative spline functions are cal...In this paper, the optimization of quantizer’s segment threshold is done. The quantizer is designed on the basis of approximative spline functions. Coefficients on which we form approximative spline functions are calculated by minimization mean square error (MSE). For coefficients determined in this way, spline functions by which optimal compressor function is approximated are obtained. For the quantizer designed on the basis of approximative spline functions, segment threshold is numerically determined depending on maximal value of the signal to quantization noise ratio (SQNR). Thus, quantizer with optimized segment threshold is achieved. It is shown that by quantizer model designed in this way and proposed in this paper, the SQNR that is very close to SQNR of nonlinear optimal companding quantizer is achieved.展开更多
目的对浙江省肾综合征出血热（Hemorrhagic Fever with Renal Syndrome，HFRS）疫区-龙泉，新分离到的毒株的S基因片段进行克隆并进行序列测定及分析，以确定毒株的型别和基因变异程度，为进一步研究病毒进化和变异提供了有利条件。方...目的对浙江省肾综合征出血热（Hemorrhagic Fever with Renal Syndrome，HFRS）疫区-龙泉，新分离到的毒株的S基因片段进行克隆并进行序列测定及分析，以确定毒株的型别和基因变异程度，为进一步研究病毒进化和变异提供了有利条件。方法采用直接免疫荧光检测疫区鼠肺HV抗原。将HV抗原阳性的鼠肺标本接种Vero-E6细胞，分离病毒。参考GenBank发表的汉坦病毒核蛋白基因序列，设计合成一对引物，提取分离株细胞培养物的总RNA，应用逆转录聚合酶链反应（RT-PCR）方法扩增新毒株S片段基因，并克隆入载体，纯化后进行核苷酸序列测定及分析。结果成功分离到的新毒株S片段的全基因序列共1 700个核苷酸，只有一个开放读码框架，共编码429个氨基酸。新毒株与HTN型毒株比较，核苷酸同源率为85.7%-91.9%。与SEO型毒株比较，核苷酸同源率为71.2%-75%，表明该毒株为HTN型毒株。结论浙江HFRS疫区新分离汉坦病毒株可以定型为HTN型毒株，可能为新的亚型。展开更多
基金Serbian Ministry of Education and Science through Mathematical Institute of Serbian Academy of Sciences and Arts(Project III44006)Serbian Ministry of Education and Science(Project TR32035)
文摘In this paper, the optimization of quantizer’s segment threshold is done. The quantizer is designed on the basis of approximative spline functions. Coefficients on which we form approximative spline functions are calculated by minimization mean square error (MSE). For coefficients determined in this way, spline functions by which optimal compressor function is approximated are obtained. For the quantizer designed on the basis of approximative spline functions, segment threshold is numerically determined depending on maximal value of the signal to quantization noise ratio (SQNR). Thus, quantizer with optimized segment threshold is achieved. It is shown that by quantizer model designed in this way and proposed in this paper, the SQNR that is very close to SQNR of nonlinear optimal companding quantizer is achieved.
