WAPENAAR, C.P.A., HERRMANN, P., VERSCHUUR, D.J. and BERKHOUT, A.J. 1990. Decomposition of multicomponent seismic data into primary P-and S-wave responses. Geophysical Prospecting 38,633-661.Inversion of multicomponent seismic data can be subdivided in three main processes : (1) Surface-related preprocessing (decomposition of the multicomponent data into ' primary ' Pand S-wave responses). (2) Prestack migration of the primary P-and S-wave responses, yielding the (angle-dependent) P-P, P-s, s-P and s-S reflectivity of the subsurface. (3) Targetrelated post-processing (transformation of the reflectivity into the rock and pore parameters in the target). This paper deals with the theoretical aspects of surface-related preprocessing.In a multicomponent seismic data set the P-and S-wave responses of the subsurface are distorted by two main causes: (1) The seismic vibrators always radiate a mixture of P-and S-waves into the subsurface. Similarly, the geophones always measure a mixture of P-and S-waves. (2) The free surface reflects any upgoing wave fully back into the subsurface. This gives rise to strong multiple reflections, including conversions. Therefore, surface-related preprocessing consists of two steps : (1) Decomposition of the multicomponent data (pseudo P-and S-wave responses) into true P-and S-wave responses. In practice this procedure involves (a) decomposition per common shot record of the particle velocity vector into scalar upgoing P-and S-waves, followed by (b) decomposition per common receiver record of the traction vector into scalar downgoing P-and S-waves. (2) Elimination of the surface-related multiple reflections and conversions. In this procedure the free surface is replaced by a reflection-free surface. The effect is that we obtain 'primary' Pand S-wave responses, that contain internal multiples only. 633 634 C. P. A. WAPENAAR ET AL.An interesting aspect of the procedure is that no knowledge of the subsurface is required. In fact, the subsurface may have any degree of complexity. Both the decomposition step and the multiple elimination step are fully determined by the medium parameters at the free surface only. After surface-related preprocessing, the scalar P-and S-wave responses can be further processed independently by existing scalar algorithms.

Verification is usually performed on a high-level view of the software, either specification or program source code. However in certain circumstances verification is more relevant when performed at the machine code level.This paper focuses on automatic test data generation from a standalone executable. Low-level analysis is much more difficult than high-level analysis since even the control-flow graph is not available and bit-level instructions have to be modelled faithfully. We show how "path-based" structural test data generation can be adapted from structured language to machine code, using both state-of-the-art technologies and innovative techniques. Our results have been implemented in a tool named OSMOSE and encouraging experiments have been conducted.

No abstract

International audienceThis paper presents the BINCOA framework, whose goal is to ease the development of binary code analysers by providing an open formal model for low-level programs (typically: executable files), an XML format for easy exchange of models and some basic tool support. The BINCOA framework already comes with three different analysers, including simulation, test generation and Control-Flow Graph reconstruction