Abstract: When an element process has been given, an initial graph is produced, a dependency graph is deformed from the initial graph, and then the dependency graph is deconstructed so that a process expression tree is produced.

Abstract: A method of controlling information on data links is provided which allows a user to establish a new link between a data which is being referred to by some other user or task and another data and to update and delete pieces of link information which has been established for the former data. A data layer composed of a plurality of data and a link layer for holding link information which represents link relationships among the plurality of data are disposed separately. In the case that a user refers to a data in the data layer except when link information in the link layer is being referred to or updated, other users are inhibited from modifying the data and are allowed to read the data. Furthermore, other users are allowed to read and modify the link information in the link layer which corresponds to the data being referred to.

Abstract: A data-driven type computer system including an input limiting section for monitoring a current number of packets existing in the circular pipeline of the system while being processed. The input limiting section is adapted to control packets from being inputted from the external unit when the current number of packets exceeds a specified threshold value which is greater than a minimum packet number existing in the circular pipeline and which allows the attainment of the highest possible throughput of the system. The input limiting section further includes a predictive control unit to preliminarily analyze a current data flow graph to be processed in the system and also to take order in rank a possible rate of increase in the quantity of packets generated by a copying operation as well as a possible rate of reduction in the prior processing by the system.