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This paper investigates the protection of reinforced concrete (RC) structures from Mortar 120 mm HE (high explosive) top attacks. Two multi-layered mitigation systems are proposed to be added to the roofs of RC structures to achieve full protection against the destructive effects of Mortar 120 mm (i.e., ballistic penetration and explosion). The proposed mitigation systems combine relatively high-strength materials to stop or slow down the projectile, along with lightweight porous materials to attenuate the explosion shock wave. The porous materials also serve to increase the thickness of the proposed mitigation systems, thereby increasing the explosion stand-off distance. Traditional construction materials such as steel and RC were used as cost-effective high-strength materials, while commercial rigid polyurethane foam and lightweight bricks were examined as shock wave absorbers. Two firing tests of the 120 mm bomb from cannon barrels were conducted against one-story RC structures strengthened with the proposed protection systems. A numerical simulation of the real firing tests was performed using the Autodyn hydrocode to further analyze the performance of the constituent components in mitigating the effects of the rounds. The current study demonstrates that the proposed mitigation systems, based on the concept of multi-layering, are efficient and have their merits in countering Mortar 120 mm HE attacks. [ABSTRACT FROM AUTHOR]

This paper presents database security approach for complete hiding of sensitive association rules by using six novel algorithms. These algorithms utilize three new weights to reduce the needed database modifications and support complete hiding, as well as they reduce the knowledge distortion and the data distortions. Complete weighted hiding algorithms enhance the hiding failure by 100%; these algorithms have the advantage of performing only a single scan for the database to gather the required information to form the hiding process. These proposed algorithms are built within the database structure which enables the sanitized database to be generated on run time as needed.