Optimizing Performance of Hadoop with Parameter Tuning

Optimizing Hadoop with the parameter tuning is an effective way to greatly improve the performance, but it usually costs too much time to identify the optimal parameters configuration because there are many parameters. Users are always blindly adjust too many parameters and are sometimes confused about which one could be changed at a higher-priority. To make optimization easier, classifying the parameter based on different applications will be helpful. In this paper, we will introduce a method that can classify these parameters in order that users can optimize performance more quickly and effectively for different applications

Hysteretic Behavior of Prestressed Concrete Bridge Pier with Fiber Model

The hysteretic behavior and seismic characteristics of the prestressed concrete bridge pier were researched. The effects of the prestressed tendon ratio, the longitudinal reinforcement ratio, and the stirrup reinforcement ratio on the hysteretic behavior and seismic characteristics of the prestressed concrete bridge pier have been obtained with the fiber model analysis method. The analysis show some results about the prestressed concrete bridge pier. Firstly, greater prestressed tendon ratio and more longitudinal reinforcement can lead to more obvious pier’s hysteresis loop “pinching effect,” smaller residual displacement, and lower energy dissipation capacity. Secondly, the greater the stirrup reinforcement ratio is, the greater the hysteresis loop area is. That also means that bridge piers will have better ductility and stronger shear capacity. The results of the research will provide a theoretical basis for the hysteretic behavior analysis of the prestressed concrete pier

Quantitative analysis of iris changes after physiologic and pharmacologic mydriasis in a rural Chinese population

Purpose. To estimate and compare the change in iris cross-sectional area (IA) and iris volume (IV) following physiologic and pharmacologic pupil dilation in primary angle closure suspects (PACS) and normal subjects. Methods. Anterior segment-optical coherence tomography (AS-OCT) measurements in light, dark, and following pharmacologic dilation were obtained on 186 PACS and 224 normal subjects examined during the 5-year follow-up of the Handan Eye Study. Iris cross-sectional area, IV, and other biometric parameters calculated using the Zhongshan angle assessment program in the right eyes of all subjects were analyzed. Results. The mean IA and IV decreased in dark compared with light and after pharmacologic dilation in both PACS and normal eyes. This change was statistically significant in normal eyes: light versus pharmacologic dilation for IA (P= 0.038) and for IV, both light versus dark (P= 0.031) and light versus pharmacologic dilation (P= 0.012). A longer axial length (P= 0.028) and a greater change in pupil diameter (PD) (

Effect of dispersion on indistinguishability between single-photon wave-packets

With propagating through a dispersive medium, the temporal-spectral profile of laser pulses should be inevitably modified. Although such dispersion effect has been well studied in classical optics, its effect on a single-photon wave-packet, i.e., the matter wave of a single-photon, has not yet been entirely revealed. In this paper, we investigate the effect of dispersion on indistinguishability of single-photon wave-packets through the Hong-Ou-Mandel (HOM) interference. By dispersively manipulating two indistinguishable single-photon wave-packets before interfering with each other, we observe that the difference of the second-order dispersion between two optical paths of the HOM interferometer can be mapped to the interference curve, indicating that (1) with the same amount of dispersion effect in both paths, the HOM interference curve must be only determined by the intrinsic indistinguishability between the wave-packets, i.e., dispersion cancellation due to the indistinguishability between Feynman paths; (2) unbalanced dispersion effect in two paths cannot be cancelled and will broaden the interference curve thus providing a way to measure the second-order dispersion coefficient. Our results suggest a more comprehensive understanding of the single-photon wave-packet and pave ways to explore further applications of the HOM interference