2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/119282Three inverse boundary value problems for the heat equations in one space dimension are considered. Those three problems are: extracting an unknown interface in a heat conductive material, an unknown boundary in a layered material or a material with a smooth heat conductivity by employing a single set of the temperature and heat flux on a known boundary as the observation data. Some extraction formulae of those discontinuities which suggest a relationship between the travel time of a {\it virtual} signal and the observation data are given by applying the enclosure method to the problems.27pagesAnalysis of PDEsMathematical Physics35R30;80A23text