A graphical off-line robot programming system should not only be able to simulate various types of robot movement graphically, it should also be able to use graphics to interact with binary sensors, actuators and etc., in order to simulate logic-related and other functions of robot languages, such as testing and branching, looping, communication and external event handling graphically. We present a graphical off-line robot programming system which has some of these additional features. In particular, it incorporates a geometrical representation of logical conditions into the geometrical representation of the robot and workspace and it allows conditional statements to be programmed in a geometric setting.

A formal modeling system intended for modeling the flow of parts, tools, information, and material on the factory floor is developed. The models are to be used as part of a generic control system for the factory floor, that is, a control system capable of controlling an arbitrary factory floor making an arbitrary mix of parts. The basic approach is to model a factory floor and process plans as "games" in which 1) there are pieces or, as they will be referred to, entities, 2) entities can be in contact with one aniother, and 3) the moves of the game correspond to changing the pattern of contacts. The game also allows an entity to be designated as a substructure of another entity. This allows a hierarchical decomposition of a model. The approach of the paper is in the spirit of first-order logic in the sense that a formal model is viewed as a structure or instantiation of a quasi first-order logical system.

Decomposition theory is concerned with the structures that arise in the decomposition of systems. It states from the premise that any method of system decomposition is based, either explicitly or implicitly, on some concept of dependence. The formal setting of decomposition theory is the dependence, an ordered-triple (E,M,D), whereEis a nonempty set,Mis a collection of subsets ofE, andDis a relation from nonempty subsets ofMto subsets ofM. If (A,B)∈D, it is said that `Adepends onB'. Duality is considered here. In particular, given a dependence (E,M,D), its dual is a dependence (E,M,D'). Duality plays a role here similar to duality in other formal systems such as graphs, matroids, lattices, circuits, control systems, and so forth. It deepens our understanding of dependence by pairing seemingly different concepts.

Although system decomposition is a fundamental tool of systems theory, no theory exists that unifies its many manifestations. The beginnings of such a theory are proposed here. The goal of this theory is to understand the structure of decompositions of large complex systems. In particular, it is to uncover those structural features that are implicit in each specific method of decomposition. The key assumption is that any system decomposition is based, either explicitly or implicitly, on some concept of dependence. Therefore, study of decomposition becomes enmeshed with the study of dependence. Three aspects of system decomposition are emphasized. First, various kinds of dependence are employed in system decomposition. Second, refinement of a decomposition to obtain a new one is an important part of decomposition. Third, shifts in point of view and level of detail can lead to different decompositions. No attempt is made to cover all aspects of decomposition theory. Rather, attention is focused on developing some properties of generalized dependences. A number of examples are presented showing the applicability of the ideas presented here to a variety of systems. These include relational data bases, finite-state machines, cognitive maps, Petri nets, and vector processor computation.