We describe a system, G2A, that produces ACT-R models from GOMS models. The GOMS models can contain hierarchical methods, visual and memory stores, and control constructs. G2A allows ACT-R models to be built much more quickly, in hours rather than weeks. Because GOMS is a more abstract formalism than ACT-R, most GOMS operators can be plausibly translated in different ways into ACT-R productions...

In this paper we i.ntroduce R, a distributed public key management service for open networks. f’l offers interfaces by which clients can register, retrieve, and revoke public keys, and escrow, use (to decrypt messages), and recover private keys, all of which can be subjected to access control policy. R is built using multiple servers in a way that ensures its correct operation despite the malic...

∗ Undergraduate Research Participants Abstract Argonne’s ATLAS (Argonne Tandem-Linac Accelerator System) control system comprises two separate database concepts. The first is the distributed real-time database structure provided by the commercial product Vsystem [1]. The second is a more static relational database archiving system designed by ATLAS personnel using Oracle Rdb [2] and Corel Parad...

We propose a fully parallel calculus of synchronizing processes. The calculus was deeply inspired by LOTOS, of which it inherits multi-party synchronization in process parallel composition. On the other hand, its semantics is not interleaving whereas LOTOS one is. The model we propose is somehow in between Milner's SCCS and ASCCS in that independent actions are performed simultaneously, whereas...

The aim of the paper is to introduce the notion of a transformation unit together with its interleaving semantics and to study it as a means of constructing large graph transformation systems from small ones in a structured and systematic way. A transformation unit comprises a set of rules, descriptions of initial and terminal graphs, and a control condition. Moreover, it may import other trans...

We consider the gradient flow of a one-homogeneous functional, whose dual involves the derivative of a constrained scalar function. We show in this case that the gradient flow is related to a weak, generalized formulation of a Hele-Shaw flow. The equivalence follows from a variational representation, which is a variant of well-known variational representations for the Hele-Shaw problem. As a co...

We study the stability and stabilizability of a continuous-time switched control system that consists of the time-invariant n-dimensional subsystems ẋ = Aix+ Bi(x)u (x ∈ R , t ∈ R+ and u ∈ R mi ), where i ∈ {1, . . . , N} and a switching signal σ(·) : R+ → {1, . . . , N} which orchestrates switching between these subsystems above, where Ai ∈ R, n ≥ 1, N ≥ 2, mi ≥ 1, and where Bi(·) : R → Ri sat...

This paper presents a technique, called loop dissevering, to temporally partitioning any type of loop presented in programming languages. The technique can be used in the presence of complex loops that oversize the physically available hardware resources. Unlike loop fission or distribution, the technique can be applied to all types of loops and it is not constrained by loop dependences. Thus, ...

The paper is devoted to an analysis of the concurrent features of asynchronous systems. A preliminary step is represented by the introduction of a non-interleaving extension of barbed equivalence. This notion is then exploited in order to prove that concurrency cannot be observed through asynchronous interactions, i.e., that the interleaving and concurrent versions of a suitable asynchronous we...

R offers several extension packages that allow it to perform parallel computations. These operate on fixed points in the program flow and make it difficult to deal with nested parallelism and to organize parallelism in complex computations in general. In this article we discuss, first, of how to detect parallelism in functions, and second, how to minimize user intervention in that process. We p...