Through the analysis of situated use of artifacts, it is shown that the activity of using artifacts is always embedded in multiple course of actions and in collaborative activities. At the same time, diverse artifacts organize multiple contexts of work. Further, I analysed how the use of tools becomes resources for reciprocally displaying what each particpant is doing by using tools while the use of tools and technologies is always embedded in collaborative activities. Thus, I focus on mutual constitution of artifacts and collaborative activities. Indeed, it includes recovering and renovating of the whole activity by which original state of the object was produced.
Restoration is objective.
It is a real and concrete activity as well as oriented to some material object. The activity of restoration is ubiquitous, which includes not onlyarcaeologist's one, but lay person's mundane activities. Restoration is not only oriented to some past state and past activity. Restoration is between the past and the current activity system. In some case, restoration is used for renovation of the current acitivity system.