3 Power Tomography 23
3.1 Preliminaries ............................. 23
3.1.1 Leakage current........................ 23
3.1.2 Global flow of the power tomography............ 25
3.2 Noninvasive tomography....................... 26
3.3 Fast tomography by compressive sensing.............. 30
3.3.1 Sparse representation..................... 30
3.3.2 Regular grid tomography................... 32
3.3.3 Irregular grid tomography.................. 33
3.4 Tomography using spatial constraints (TUSC)........... 35
3.4.1 Adding spatial constraints.................. 35
4 Delay Tomography 38
4.1 Preliminaries ....................... 38
4.1.1 Delay variation model .................... 38
4.1.2 Sensitizable paths....................... 39
4.1.3 Globalflowofthedelaytomography............ 39
4.2 Delay estimation by ^2-norm minimization............. 41
4.3 Delay estimation using compressive sensing............. 46
4.3.1 Sparse representation of variations ............. 47
4.3.2 Gates on the regular grids.................. 49
4.3.3 Gates on the irregular grids................. 50
iv