Image Copy-Move Forgery Detection Using SURF in Opponent Color Space

Most existing methods for image copy-move forgery detection(CMFD)operate on grayscale images. Although the keypoint-based methods have the advantages of strong robustness and low computational cost,they cannot identify the flat duplicated regions without reliable extracted features. In this paper, we propose a new CMFD method by using speeded-up robust feature(SURF)in the opponent color space. Our method starts by converting the inspected image from RGB to the opponent color space. The color gradient per pixel is calculated and taken as the work space for SURF to extract the keypoints. The matched keypoints are clustered and their geometric transformations are estimated. Finally, the false matches are removed. Experimental results show that the proposed technique can effectively expose the duplicated regions with various transformations, even when the duplication regions are flat.

Wave Height Distribution for Spilling Waves in and outside the Surf Zone

The wave characteristics affecting coastal sediment transport include wave height, wave period and breaking wave direction. Wave height is a critical factor in determining the amount of sediment transport in the coastal area. The force of sediment transport is much more intense under breaking waves than under non-breaking waves. Breaking waves exhibit various patterns, principal- ly depending on the incident wave steepness and the beach slope. Based on the equations of con- servation of mass, momentum and energy, a theoretical model for wave deformation in and outside the surf zone was obtained, which is used to calculate the wave shoaling, wave set-up and set- down and wave height distributions in and outside the surf zone. The analysis and comparison were made about the breaking point location and the wave height decay caused by the wave breaking and the bottom friction. Flume experiments relating to the spilling wave height distribution across the surf zone were conducted to verify the theoretical model. Advanced wave maker, data sampling de- vices and data processing system were utilized in the flume experiments with a slope covered by sands of different diameters to facilitate the observation and research on the wave transformation and breaking. The agreement between the theoretical and experimental results is good.

DVD碟报

《惊变28周》，《冒牌天神2》，《冲浪企鹅》，《星条旗永不落》。

Measurement of associations between mobile calls and mobile-internet surfing

Measuring mobile calls data is an increasingly import issue,which will benefit to the understanding of the behavior of mobile users and assist telecom operators to optimize their business strategies.The existing researches on cell phone data measurement only focus on mobile calls or on mobile-internet surfing and little researches focus on the interactions of behaviors between them.In this paper,some basic factors of the association between mobile calls and mobile-internet surfing are measured.Then first their distributions are compared and the preference of users is quantified.After that experiments on the curve fitting of both the whole and parts of these distributions are done.Through the comparison of the correlation coefficients and Fourier fitting parameters,different behaviors is found between workdays and weekends,as well as Saturdays and Sundays in mobile-call distributions.Besides,the results of our observation show that the mobile-internet traffic does not always monotone increase with the increase of online time,significant changes are observed after 8hours of mobile-internet surfing.

软件拼盘秀

如果你觉得自己的软件比无名介绍的更有特点，或者你挖掘了《冲浪工具》介绍软件的一些小技巧，请和无名联系：tools@netfriends．com．cn，标明文章类型是“软件拼盘秀”，这里再强调一下，提供的软件或者是杂志介绍过的，你发掘了更好的技巧；或者是功能和使用与杂志上介绍的软件相似，有一定特性。

软件大药房

从本期开始杂志的各个栏目都有了重大的变化，《冲浪工具》板块也引入了“软件大药房”这个子栏目，小编会筛选一部分具有代表性的问题进行开药诊断，当然这里解决的方法都是利用软件。

突破常规——拯救数据也要与时俱进

可能很多朋友已经知道，即使是将删除到回收站中的文件执行“清空”操作。这些文件仍然可以被非常轻松的恢复出来。甚至对硬盘进行格式化。借助某些高级恢复工具也可以被顺利恢复。目前已经有很多类似软件应运而生。以前《冲浪工具》也曾给大家介绍过。但恢复也要与时俱进。如果遇到难缠的文件。可以试试其它的新兴工具。说不定有意外的收获。在开始之前。我们有必要简单了解一下系统删除方面知识。

软件拼盘秀

如果你觉得自己的软件比无名介绍的更有特点，或者你挖掘了《冲浪工具》介绍软件的一些小技巧，请和无名联系：tools@netfriends.com.cn、标明文章类型是“软件拼盘秀”。

Response of air gap and slamming loadings on semi-submersible platform

The present research deals with the numerical prediction of the air gap within the 6th generation of deepwater drilling floating semi-submersible platform and the experimental studies on the slamming loadings onto the structure. The survivability of the floating model with a mooring system was tested under extreme wave of 10-year return period. In the numerical simulation of the Gaussian method,the narrow band model was applied to obtain the first-order wave surface equation and the modified second-order wave surface equation. The hydrodynamic responses of the floating body,i.e. radiation damping,added mass,second-order wave excitation force and drifting force,were computed by using the potential flow theory based on higher order boundary element method in frequent domain. In the experimental analysis,high-frequency sensors were installed at the lower deck to measure the wave slamming loads. Equivalent truncated mooring system was applied to make sure position of the floating body in the wave tank. The comparison between the numerical and experimental results showed the numerical model underestimated the air gap of the floating body. Nevertheless,the predictions of the high risk spots underneath the floating deck that is prone to wave slamming obtained from both models were agreeable to each other. The experimental results also revealed that the wave slamming events often occurred at the connection point between the rear columns and the lower deck.

Scour effect on a sea-crossing bridge under combined action of service and extreme seismic loads

Foundation scour is an important cause for structural failure of sea-crossing bridges. Usually, the sea-crossing bridges operate under the harsh natural environment in which service wind, wave and vehicle loads are stronger and extreme loads such as earthquake, hurricane, and ship collision, are more frequent. As a result of the foundation scour,the dynamic behavior of bridge under different combined action of service and extreme loads may be further escalated.In particular, this work has investigated the scour effect on a sea-crossing bridge under service wind, wave and vehicle loads as well as extreme seismic loads. The dynamic coupled earthquake-wind-wave-vehicle-bridge(EWWVB) system is established by considering the interactions within the system, and the p-y curve method is used to calculate the loaddisplacement relation of the pile and soil under various levels of foundation scour. After that, a case study has been performed on a cable-stayed bridge with foundation scour. The results indicate that the dynamic characteristics of bridge structure will change after considering bridge scour, and the dynamic responses of bridge and vehicle will be affected to different degrees under service and seismic loads considering bridge scour.

冲浪

①“爸爸妈妈和我开着车……”到底是谁开、车呢？还是你家每个人都开了车？同学们看看这句话该如何更改更好些？

Equilibrium scour depth at offshore monopile foundation in combined waves and current

Unlike the pier scour in bridge waterways,the local scour at offshore monopile foundations should take into account the effect of wave-current combination.Under the condition of wave-current coexistence,the water-soil interfacial scouring is usually coupled with the pore-pressure dynamics inside of the seabed.The aforementioned wave/current-pile-soil coupling process was physically modeled with a specially designed flow-structure-soil interaction flume.Experimental results indicate that superimposing a current onto the waves obviously changes the pore-pressure and the flow velocity at the bed around the pile.The concomitance of horseshoe vortex and local scour hole around a monopile proves that the horseshoe vortex is one of the main controlling mechanisms for scouring development under the combined waves and current.Based on similarity analyses,an average-velocity based Froude number(Fra)is proposed to correlate with the equilibrium scour depth(S/D)at offshore monopile foundation in the combined waves and current.An empirical expression for the correlation between S/D and Fra is given for predicting equilibrium scour depth,which may provide a guide for offshore engineering practice.

外媒

“与了无新意的剧情相比，还是片中海浪的场景更具说服力。”——《综艺》关于《冲浪男人》