@article{oai:nagoya.repo.nii.ac.jp:00005336, author = {Ushiama, Taketoshi and Watanabe, Toyohide}, journal = {Proceedings of 20th International Conference on Computer Software and Applications}, month = {Aug}, note = {Until today, techniques for modeling and managing the time-varying charcteristics of entities in database have been proposed. These techniques are mainly classified into two categories: time-stamp method and version method. These methods limit the representation/manipulation capabilities because the change of class membership for an object is not well specified and the transitional states must be related mutually along the system-defined time axis. In this paper, we propose a method, which is basically derived from the object-oriented paradigm, for modeling time-varying characteristics of entities so as to be free from the above two limitations in the traditional methods. We introduce two representation media: core and surface. The core represents invariant features of entity, while the surface denotes variant features of entity. A snapshot of an entity is represented as an aspect, which is a database instance composed of the core and surfaces.}, pages = {420--425}, title = {A representation method of time-varying characteristics of entity on the basis of core-surface concept}, year = {1996} }