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With the rapid development of video surveillance and 3D geographic information system (GIS), object detection and spatial location have gradually become one of the supporting capabilities of various applications. The primary application mode of traditional surveillance video and 3D geographic information fusion is video projection to the 3D geographic scene to form the 3D virtual geographic scene. Research on object detection and spatial location method based on the 3D virtual geographic scene can significantly improve intelligence and spatialization application ability. This paper proposes a method of object detection and spatial positioning of monocular camera based on 3D virtual geographical scene and realizes monocular camera object detection and geographic coordinate calculation. The method is composed of three algorithms, (1) fusion constructing algorithm of the 3D virtual geographic scene, (2) object detection algorithm based on convolutional neural network, (3) coordinate calculation algorithm based on the 3D virtual geographic scene. After the location error and application experiment verification, the positioning accuracy error of this method is positively correlated with the viewing distance, and the object detection and spatial location are realized. The method is propitious to various 3D geographic scenes, which can effectively improve the spatial understanding of the object in the surveillance. It has application value to all kinds of 3D GIS.

Web applications, as a conventional platform for sensitive data and important transactions, are of great significance to human society. But with its open source framework, the existing security vulnerabilities can easily be exploited by malicious users, especially when web developers fail to follow the secure practices. Here we present a distributed scanning system, FalconEye, with great precision and high performance, it will help prevent potential threats to Web applications. Besides, our system is also capable of covering basically all the web vulnerabilities registered in the Common Vulnerabilities and Exposures (CVE). The FalconEye system is consists of three modules, an input source module, a scanner module and a support platform module. The input module is used to improve the coverage of target server, and other modules make the system capable of generic vulnerabilities scanning. We then experimentally demonstrate this system in some of the most common vulnerabilities test environment. The results proved that the FalconEye system can be a strong contender among the various detection systems in existence today.

The flexjoint of TLP (Tendon Leg Platform) tendon connector is designed to provide flexibility in rotation while bearing vertical load. The flexjoint is spherical and consists of laminated rubber and metal layers. It's necessary to study the effects of Poisson's ratio and compressibility of the rubber on the flexjoint. Meanwhile, the effect of the number of metal layers is also studied. The 2D axisymmetric nonlinear finite element analysis is carried out to simulate the static behavior of the flexjoint under vertical compression. The Mooney-Rivlin strain energy function is used to describe the constitutive relation of the rubber. The effects of Poisson's ratio of the rubber and the number of metal layers on the vertical compression stiffness and the maximum equivalent stress of the flexjoint are studied. The increase of the number of metal layers will improve the vertical compression stiffness and reduce the maximum equivalent stress. When Poisson's ratio of the rubber material increases from 0.49 to 0.49995, the vertical compression stiffness of the flexjoint increases by 14.7 times. The maximum equivalent stress decreases as the number of metal layers increases and, in this case, the reduction is 115Mpa.

This paper presents a novel start-up scheme for the modular multilevel converter. Firstly a charging process model is introduced and the process of the proposed start-up scheme is presented. Then the maximum current and current-time formula during the charging process is derived. The mathematical solution of the formulas is used to compare with the results from a three-phase simulation using Matlab/Simulink. By using this method, no auxiliary dc source or extra dc breaker is needed. Finally the proposed start-up scheme is verified on a single phase downscaled MMC prototype. The experiment shows that the proposed method can charge the voltage of each module capacitor to the rated value with smaller surge current.

Groundwater constitutes the largest single source of fresh water in many parts of the world and provides a risk buffer to sustain critical water demands during cyclic and prolonged dry periods, especially in semi-arid and arid regions. Intensification of agriculture, increases in land area devoted to arable crops, intensification of animal husbandry, and a move away from arable rotations toward monoculture have caused groundwater fast depletion of already critically low stocks accompanied by persistent degradation of water quality due to salinization, and contamination by pesticides and fertilizers. An assessment study of groundwater nitrate contamination conditions in the Minqin Basin was conducted in support of efforts to manage water quality in the basin. There were 65 observation well water samples collected and analyzed for nitrate. The results of analysis include distribution of nitrate contamination and probability of exceedance of drinking-water nitrate regulatory limit. The concentration of the nitrate is ranges between 0.03 and 59.75 mg L -1 . There are NO 3 - -N levels of the 1.54% samples in groundwater exceeded standard limits (10 mg L -1 ) for drinking water in the basin. Results thus indicated that most of the groundwater of the study area is presently safe for drinking purpose but some anthropogenic activities associated with intensive cultivation had a positive influence on its loading with NO 3 - . The distribution of nitrate contamination conditions was clarified in this study by using GIS, which will be applicable to the effective management of groundwater quality.