The authors use Passive DNS to log domain name query history of real campus network environment, and construct eighteen feature sets grouping by diversity, time, growth, and relevance, and then propose a model detect Fast-Flux Domains using random forest algorithm. The result shows that the proposed model can classify domains with accuracy over 90% by cross validation experiments. The model can detect Fast-Flux domains in the datasets used in this study more effectively compared with Fluxbuster.

The pedestrian wind environment around a commercial center in Beijing was investigated in the wind tunnel. The pedestrian level wind velocity distributing could be attained by analyzing the result of test points arranged around the models. Based on the pedestrian level wind comfort criteria, which categorized different ranges of wind velocity as being appropriate for certain types of pedestrian activities and gave the corresponding acceptable frequencies of occurrence, the pedestrian wind environment was assessed quantitatively combined with the local wind climate statistic records. Some useful guide was provided to improve the comfortability in the potential uncomfortable or dangerous locations.

Dynamic mesh method based on numerical simulation method of CFD was adopted. The changes of wind velocity in pedestrian level were calculated when the train entered, passed through and left the station at high speed (80 km/h). 63 monitor points at the pedestrian height were arranged to assess the influence of train wind quantitatively. The range for the pedestrian safety and comfort were given based on the proper wind comfort criteria, which could provide useful guide to platform design

A new method is proposed to correct the wind speed data in the non-standard terrain on the basis of daily records. The reference wind speeds of Beijing and Dalian are calculated based on the original and corrected wind data, respectively. The corrected data are more close to the stationary process because the terrain variations of the meteorological station have been taken into consideration by the correction coefficient. It’s concluded through likelihood ratio tests that the Gumbel distribution is a valid model for the statistics of annual maximum wind speed and the corrected wind data shows better statistical characteristic. It is suggested that the wind records in the non-standard terrain should be corrected in advance to obtain the reliable reference wind pressure.

The pierced enclosure outside the glass curtain wall can affect the wind pressure on building surface. The results of wind tunnel test show that the basic pressure distributions on the glass curtain wall isn't changed, although the pressure value is affected by the additional pierced enclosure. It has significant influence on the region close to the edge of pierced enclosure due to the change of the position of flow separation. Under the condition of porosity 55% ,the average pressure is reduced by 10% when the pierced enclosure is on the windward side or in the region where flow separates; while the pressure is increased slightly when the pierced enclosure is on the leeside. The fluctuating pressure is reduced by 10% due to the weakening of turbulent energy by pierced enclosure. In conclusion, the pierced enclosure has positive influence on the safety of the glass curtain wall.

Compressible turbulent channel flows at two Mach numbers (M = 0.8 and 1.3 ) are simulated by the numerical integration of the Navier, Stokes equations with a high, order compact finite difference scheme. The comparative studies of incompressible and compressible flows indicate that the effect of compressibility on the scaling exponents is small in the region near y+ = 20 and in the center while it is significant in the viscous sublayer (y+＝5.5) and the log, law region (y+≈120). Further studies on the variation of the relative scaling exponent show that the channel can be divided into four distinct zones according to their scaling behavior: viscous sublayer and lower edge of buffer layer (Ⅰ); the outer part of the buffer layer and lower part of log region (Ⅱ); the major part of the log region and lower edge of the center region (Ⅲ); and finally the other part of the center region (Ⅳ). The variation of the scaling exponents with the compressibility is the most remarkable in the zone Ⅰ and Ⅲ. Finally, it is found that the most intermittent region exactly coincides with the location of the maximum Reynolds shear stress.

The flow field of a large storage yard with windbreak was investigated in the wind tunnel under three dominant wind directions. The wind speed was measured by the so-called "omnidirectional surface wind sensor", and the qualitative flow pattern was visualized by tuft method. According to the experimental results, the shelter effect of the porous windbreak fence was evaluated. It was found that the wind speed significantly decreased behind the windbreak, by 80% at most. However, at some wind direction a large bubble appeared behind the fence due to the low porosity of 30%. Thus its necessary to improve the design of the windbreak fence. In addition, it was verified that the shelter effect for a certain storage yard was related to the local terrain and accordingly the given conditions should be taken in consideration.