Dynamic compaction is a soil improvement method which has been widely used for the increase of bearing capacity through stress wave propagation during heavy tamping. The cost and time of project implementation can be effectively curtailed by developing a model that can be used in the design of dynamic compaction operations. The numerical models offered so far are mostly one or two-dimensional, ...

Dynamic Compaction (DC) is a common deep compaction method that is usually used for densification of coarse-grained soils. Although traditional continuum-based models such as the Finite Element Method can be successfully applied for assessment of stress distributions or deformations induced by DC, they are typically not adequate for capturing the grain scale mechanisms of soil behavior under im...

We describe a novel software verification primitive called Oblivious Hashing. Unlike previous techniques that mainly verify the static shape of code, this primitive allows implicit computation of a hash value based on the actual execution (i.e., space-time history of computation) of the code. We also discuss its applications in local software tamper resistance and remote code authentication.

We propose the notion of tamper-evident stabilization –that combines stabilization with the concept of tamper evidence– for computing systems. On the first glance, these notions are contradictory; stabilization requires that eventually the system functionality is fully restored whereas tamper evidence requires that the system functionality is permanently degraded in the event of tampering. Tamp...

In this paper, a novel camera tamper detection algorithm is proposed to detect three types of tamper attacks: covered, moved and defocused. The edge disappearance rate is defined in order to measure the amount of edge pixels that disappear in the current frame from the background frame while excluding edges in the foreground. Tamper attacks are detected if the difference between the edge disapp...

Tamper-resistant software (TRS) consists of two functional components: tamper detection and tamper response. Although both are equally critical to the effectiveness of a TRS system, past research has focused primarily on the former, while giving little thought to the latter. Not surprisingly, many successful breaks of commercial TRS systems found their first breaches at the relatively näıve tam...

The increase use of software tamper resistance techniques to protect software against undesired attacks comes an increased need to understand more about the strength of these tamper resistance techniques. Currently the understanding is rather general. In this paper we propose a new software tamper resistance evaluation technique. Our main contribution is to identify a set of issues that a tampe...