Seismic and acoustic noise from moving tracked vehicles was used to determine the seismic to acoustic signal coupling ratio (SAR) in the ground. The seismic signal received on a geophone contains some energy that has propagated as seismic waves and some energy that couples from acoustic waves to seismic waves in the vicinity of the geophone. We use the frequency domain coherence between the mic...

Seismic data comprise many traces that provide a spatiotemporal sampling of the reflected wavefield. However, such informationmay suffer from ambient and random noise during acquisition, which could possibly limit the use of seismic data in reservoir locating. Traditionally, fixed transforms are used to separate the noise from the data by exploiting their different characteristics in a transfor...

seismic inversion is a method that extracts acoustic impedance data from the seismic traces. sourcewavelets are band-limited, and thus seismic traces do not contain low and high frequency information.therefore, there is a serious problem when the deterministic seismic inversion is applied to real dataand the result of deterministic inversion is smooth. low frequency component is obtained from w...

inclined retaining walls with slopes less than perpendicular are appropriate candidates in several engineering problems. yet, to the knowledge of authors, only a few analytical solution for calculation of active earth pressure on such walls, which will be usually smaller than the same pressure on vertical ones, has been presented neither in research papers nor in design codes. considering limit...

GenLOT coding has been shown an effective technique for seismic data compression, especially when compared to block-based algorithms (such as JPEG), or to wavelets. The transforms remove statistical redundancy and permit efficient compression, when used with advanced encoding techniques, such as the Embedded Zerotree Coding framework. In this work we derive a model for seismic data based on aut...

ISA and cardinality constraints are among the most interesting types of constraints in data models. ISA constraints are used to establish several forms of containment among classes, and are receiving great attention in moving to object-oriented data models, where classes are organized in hierarchies based on a generalization/specialization principle. Cardinality constraints impose restrictions ...

Silica (SiO(2)) is an abundant component of the Earth whose crystalline polymorphs play key roles in its structure and dynamics. First principle density functional theory (DFT) methods have often been used to accurately predict properties of silicates, but fundamental failures occur. Such failures occur even in silica, the simplest silicate, and understanding pure silica is a prerequisite to un...