Browsing by Author "Kittlitz, Kenneth A."

Now showing 1 - 4 of 4
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    CONSTRAINT-SOLVING IN INTERACTIVE GRAPHICS A USER-FRIENDLY APPROACH
    (1988-11-01) Maulsby, David L.; Kittlitz, Kenneth A.; Witten, Ian H.
    Solving constraints is an important part of interactive graphics, and a number of constraint solvers that operate in this domain have been designed and implemented. However, most of these systems are deficient in two respects: the method of specifying constraints is counter-intuitive, and only a restricted class of constraints is representable. After describing the problems inherent in current systems, we propose a simple constraint solver and its user interface, Metamouse. The user of this system specifies constraints by giving examples in the form of execution traces; the system induces a generalized procedure. Thus constraint specification is natural-the user simply performs his task as usual-and the class of representable constraints includes anything the user could accomplish manually with the graphics editor.
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    DISCIPLINED OBJECT-ORIENTED CONCURRENCY CONTROL
    (1993-06-01) Kittlitz, Kenneth A.
    This thesis investigates the applicability of object-oriented programming to the domain of concurrency control. Approaches to object-oriented concurrency control are described and evaluated, revealing that many do not distinguish between different concurrency control problems and do not recognize the dependencies these problems have on object interfaces and implementations. This thesis shows that such omissions make inheritance of concurrency policies complicated and error-prone, and develops an approach to object concurrency control that avoids both failings. A separation of the typing and code reuse hierarchies allows subtyping principles to be applied to the inheritance of synchronization, concurrent access control, priority and active object properties, resulting in concurrency control policies that are easily inheritable and incrementally modifiable. Automated tools are shown to play a large role in this process. The feasibility of verifying the system using a process calculus is discussed.
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    Disciplined object-oriented concurrency control
    (1993) Kittlitz, Kenneth A.; Gaines, Brian R.
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    INFERRING GRAPHICAL PROCEDURES: THE COMPLEAT METAMOUSE
    (1990-05-01) Maulsby, David L.; Witten, Ian H.; Kittlitz, Kenneth A.; Franceschin, Valerio G.
    Metamouse is a demonstrational interface for graphical editing tasks within a drawing program. The user specifies a procedure by performing an example execution trace, manipulating objects directly on the screen and creating graphical tools where necessary to help make constraints explicit. The system generalizes the user's action sequence, identifying key features of individual steps and disregarding coincidental events. It creates a program with loops and conditional branches as appropriate, and predicts upcoming actions, thereby reducing the tedium of repetitive and precise graphical editing. It uses default reasoning about graphical constraints to make initial generalizations, and enables the user to correct these hypotheses either by rejecting its predictions or by editing iconic descriptors which it displays after each action.