摘要：The collision detection is of great importance in almost every game, whether among the objects or between the object and the scene .If the author don t detect collisions, objects will intersect each other or object will intersect the scene. In this paper, the author present two algorithms that high-speed detects the collision detection between moving bullet and role with unknown trajectories in 2D environment. The objects for collision detection are bounded by the axis-aligned rectangles or circles. The known information such as world coordinate system, collision object coordinate system and collision detection area coordinate system etc, are stored in the data files in advance. The data control systems load those information into the collision detection module to handle the collision among the roles and bullets. We set coordinate values of rectangular center and four vertexes or the center point of a circle and use the distance between two points or the distance from a point to a line to see whether the object"s vertexes are enclosed in the other object. If it is true, there is a collision occurring. We improved the algorithm to make the player share the scene of running through the bullet cluster with skill and ease while avoiding being shot.

摘要：As people own more and more various smart devices, providing advertising to those devices has become a lucrative platform for different advertisement providers. However, the way advertisements are delivered to customers" smart devices needs to be improved. Many variables determine the most effective way to provide the mobile advertisement to the end-user. So a mobile advertising service based on the 4R model is needed to make the mobile advertising interesting and also useful for the customers. The correct time, location, contents and target device need to be determined in order for the advertisement to be contextual and the most effective. The 4R model is beneficial for the advertisers and the end-users alike.