An object's type is usually regarded as a contract between the object and each of its users. However, in concurrent (and sometimes also in sequential) systems it is more useful to regard a type as a contract between an object and the unity of all users: The users must be coordinated before sending messages to the object. Types in the proposed model express requirements on the coordination of us...

As parallel and distributed computers become more widely available and used, the already important process of understanding and debugging concurrent programs will take on even greater importance. We believe that visualization can help in the process. In this paper we discuss heretofore unaddressed issues in the visualization of concurrent programs, and present the Animation Choreographer. The A...

Of all the traditional (or Greek) centers of a triangle, the orthocenter (i.e., the point of concurrence of the altitudes) is probably the one that attracted the most of attention. This may be due to the fact that it is the only one that has no exact analogue for arbitrary higher dimensional simplices, for spherical and hyperbolic triangles, or for triangles in normed planes. But it possibly ha...

Combining into a consistent theory co-existing models for different phenomena in reasoning about actions can be a problem as challenging as addressing new aspects. We present a uniform theory for reasoning about actions with indirect effects in nondeterministic, concurrent, and continuous domains. We report on a case study to which our theory has been successfully applied.

A lower bound to errors of measuring object position is constructed as a function of parameters of a monocular computer vision system (CVS) as well as of observation conditions and a shape of an observed marker. This bound justifies the specification of the CVS parameters and allows us to formulate constraints for an object trajectory based on required measurement accuracy. For making the measu...

We investigated the role of foot structure on mora duration in Japanese. Our initial hypothesis was that moras in foot-final position are longer than moras in the same foot. Ten speakers of Tokyo Japanese read a set of surnames of the form CVCVCVCV, in which the second and fourth CVs were seen to correspond to foot-final moras. The analysis showed no support for foot-final mora lengthening. How...

The Inequality Necessary Condition Analyzer (INCA) is a finite-state verification tool that has been able to check properties of some very large concurrent systems. INCA checks a property of a concurrent system by generating a system of inequalities that must have integer solutions if the property can be violated. There may, however, be integer solutions to the inequalities that do not correspo...

We explore the question of the composition of invariance specifications in a context of concurrent and reactive systems. Depending on how compositionality is stated and how invariants are defined, invariance specifications may or may not be compositional. This article first examines two classic forms of invariants and their compositional properties. After pointing out what we see as deficiencie...

diagnosis for timed concurrent constraint programs! MARCO COMINI and LAURA TITOLO Dipartimento di Matematica e Informatica University of Udine Via delle Scienze, 206 33100 Udine, Italy (e-mail: {marco.comini,laura.titolo}@uniud.it)