The paper presents novel results associated with the algorithmization and solution of model initial boundary-value problems describing transformations of pulsed electromagnetic waves.The focus of electromagnetic theory is initial boundary-value and boundary-value problems for the Maxwell equations. Those are the assumed models, from which, by applying mathematical methods, we should extract physical results. The modern computer-aided research process can be divided into several stages: qualitative mathematical analysis of the initial problem; the development of algorithms and implementation of the problem in software; problem-oriented computational experiments; and physical interpretation of the results. The success of the study depends in many aspects on whether sufficiently high standards of investigation can be maintained at all these stages and whether there is an 'intellectual core' in these investigations which enables us to gain new scientific knowledge [1]. As an example of a successful implementation of such an approach that has settled a long-standing conflict between theory and experiment, we can cite the development of the theory of resonant wave scattering in the frequency domain. These results have been reported (see for example, [2]-[16] and the bibliographies contained in those references), and they have served as a basis for the development of a number of essentially new functional units and devices in millimeter and sub millimeter radio-engineering, vacuum electronics and solid-state electronics, optics and spectroscopy.The modern theory of transient electromagnetic fields is still lacking achievements that may be compared with those existing in the frequency domain, neither by the profoundness of the study, nor by the intensity of the study of electromagnetic phenomena and, as a result by their applications. However, the process of accumulation of potentialities for a break through is a process still in action. Our activity now is devoted to just these problems; for the most part it is focused on the development and implementation of robust and efficient mathematical models for transient electromagnetic theory.The content of this paper has been partially inspired by the statement from [17]: "Therefore, it becomes clear that the boundary conditions are an integral part of a PDE (partial-differential-equation) problem, and should always accompany the FDTD (finite-difference time-domain) formulation of it. This inflicts particular concerns when the problem under examination is so-called 'open' space or unbounded problem, e.g., radiating, scattering, etc., meaning that the domain of interest is unbounded in one or more spatial-coordinate directions. For such problems, there are no exact boundary conditions known".However, exact 'absorbing' conditions (or 'fully absorbing' conditions) providing efficient limitation of the computational domain of finite-difference methods do exist now, since some time back. They have already taken their proper place in electromagnetic simulation in fundamental and ap...