Configuration errors are proved to be the main reasons for network interruption and anomalies.Many researchers have paid their attention to configuration analysis and provisioning,but few works focus on understanding ...Configuration errors are proved to be the main reasons for network interruption and anomalies.Many researchers have paid their attention to configuration analysis and provisioning,but few works focus on understanding the configuration evolution.In this paper,we uncover the configuration evolution of an operational IP backbone based on the weekly reports gathered from January 2006 to January 2013.We find that rate limiting and launching routes for new customers are configured most frequently.In addition,we conduct an analysis of network failures and find that link failures are the main causes for network failures.We suggest that we should configure redundant links for the links which are easy to break down.At last,according to the analysis results,we illustrate how to provide semi-automated configuration for rate limiting and adding customers.展开更多
Introduction The discovery of cell-free fetal DNA(cff-DNA),also known as noninvasive prenatal testing(NIPT),by Lo et al.in 1997,1 has significantly changed the screening for common chromosomal abnormalities.Its widesp...Introduction The discovery of cell-free fetal DNA(cff-DNA),also known as noninvasive prenatal testing(NIPT),by Lo et al.in 1997,1 has significantly changed the screening for common chromosomal abnormalities.Its widespread acceptance globally underscores its impact.NIPT analyzes fetal DNA originating from the apoptosis of the outer cytotrophoblast,the fetal hematopoietic system,and lysis of other fetal cells.The DNA fraction increases from 10%to 15%between 10 and 20 gestational weeks.Rapid cff-DNA clearance occurs in maternal circulation,spanning from 4 minutes to 2 weeks postpartum.展开更多
Subaperture stitching （SAS） provides us with an attractive way of extending the effective aperture and dynamic range of phase measuring interferometers. Accuracy of stitching algorithm becomes the key factor in the ...Subaperture stitching （SAS） provides us with an attractive way of extending the effective aperture and dynamic range of phase measuring interferometers. Accuracy of stitching algorithm becomes the key factor in the SAS technology. In this paper, the basic principle of SAS was introduced and four modes of SAS were discussed. The stitching experiments were done through the SSI-300 workstation designed and developed indepen- dently. There were several comparisons between the four different stitching methods and the measurement of full aperture. The results suggest that the global error averaging mode with reference of subaperture near optic axis is of high precision.展开更多
In this paper, the principle of subaperture stitching interferometry was introduced. A testing stage with five degrees of freedom for stitching interferometry was built. A model based on least-squares method and error...In this paper, the principle of subaperture stitching interferometry was introduced. A testing stage with five degrees of freedom for stitching interferometry was built. A model based on least-squares method and error averaging method for data processing was estab- lished, which could reduce error accumulation and improve the precision. A 100ram plane mirror was measured with a 50mm aperture interferometer by means of stitching interferometry. Compared with the results by a 100 mm interferometer, peak to valley （PV） and root mean square （RMS） of the phase distribution residual are 0.00382 and 0.00042, respectively. It proved that the model and method are helpful for large optical measurement.展开更多
基金supported by the National Natural Science Foundation of China under Grant Nos.61602105 and 61572123China Postdoctoral Science Foundation under Grant Nos.2016M601323+1 种基金the Fundamental Research Funds for the Central Universities Project under Grant No.N150403007CERNET Innovation Project under Grant No.NGII20160126
文摘Configuration errors are proved to be the main reasons for network interruption and anomalies.Many researchers have paid their attention to configuration analysis and provisioning,but few works focus on understanding the configuration evolution.In this paper,we uncover the configuration evolution of an operational IP backbone based on the weekly reports gathered from January 2006 to January 2013.We find that rate limiting and launching routes for new customers are configured most frequently.In addition,we conduct an analysis of network failures and find that link failures are the main causes for network failures.We suggest that we should configure redundant links for the links which are easy to break down.At last,according to the analysis results,we illustrate how to provide semi-automated configuration for rate limiting and adding customers.
文摘Introduction The discovery of cell-free fetal DNA(cff-DNA),also known as noninvasive prenatal testing(NIPT),by Lo et al.in 1997,1 has significantly changed the screening for common chromosomal abnormalities.Its widespread acceptance globally underscores its impact.NIPT analyzes fetal DNA originating from the apoptosis of the outer cytotrophoblast,the fetal hematopoietic system,and lysis of other fetal cells.The DNA fraction increases from 10%to 15%between 10 and 20 gestational weeks.Rapid cff-DNA clearance occurs in maternal circulation,spanning from 4 minutes to 2 weeks postpartum.
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 60978043, 61128012, 610611 60503, and 61222506）.
文摘Subaperture stitching （SAS） provides us with an attractive way of extending the effective aperture and dynamic range of phase measuring interferometers. Accuracy of stitching algorithm becomes the key factor in the SAS technology. In this paper, the basic principle of SAS was introduced and four modes of SAS were discussed. The stitching experiments were done through the SSI-300 workstation designed and developed indepen- dently. There were several comparisons between the four different stitching methods and the measurement of full aperture. The results suggest that the global error averaging mode with reference of subaperture near optic axis is of high precision.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 61128012） and the Research Grants Council of the Hong Kong Special Administrative Region （No. 9041577）.
文摘In this paper, the principle of subaperture stitching interferometry was introduced. A testing stage with five degrees of freedom for stitching interferometry was built. A model based on least-squares method and error averaging method for data processing was estab- lished, which could reduce error accumulation and improve the precision. A 100ram plane mirror was measured with a 50mm aperture interferometer by means of stitching interferometry. Compared with the results by a 100 mm interferometer, peak to valley （PV） and root mean square （RMS） of the phase distribution residual are 0.00382 and 0.00042, respectively. It proved that the model and method are helpful for large optical measurement.
