structured plans with sharing and replication
M.
Balaban, S.E. Shimony
Abstract.
This paper focuses on the issue of shared (vs. replicated) tasks in hierarchical
plan description. We extend the notion of task networks (or plan schemas) with
constraint expressions, which determine which sub-plans may be shared among
parent plans, which must be shared,
and which must be replicated (that is, consist
of disjoint events) in the plant schema. The semantics of constraint expressions
are defined by using an intermediate, simplified, level of plans, and a base
level of structured events (concrete, "real-world" events).
Applications for this representation are in planning, plan recognition, and in
databases of plans and schedules. In all these areas, the possibility of
representing a large number of events with common structure compactly, provided
by the plan schemas, is beneficial.
optimal diagnostic
examination for local diagnosis
R.
Trobec
Abstract.
The paper deals with mesh-connected massively-parallel systems affected by
failures. The complexity of a local diagnosis procedure, based on new
definitions of the local k-diagnosability
and the r-fault-tolerance, is
analysed. It depends on distances between individual fault clusters and on fault
cluster diameters. In particular cases the minimum distance between fault
clusters can be enlarged on the account of the maximum fault cluster diameter,
e.g., by merging the two clusters. The criterion function for the optimal
diagnostic examination for local diagnosis is proposed.
NUTS:
a distributed object-oriented platform
with high level communication
functions
V.
Vlassov, M. Addibpour, E. Tyugu
Abstract.
An extensible object-oriented platform NUTS for distributed computing is
described which is based on an object-oriented programming environment NUT which
supports automatic synthesis of programs. It
is built on top of the Parallel Virtual Machine (PVM), and hides all low-level
features of the latter. The language of NUTS is a concurrent object-oriented
programming language with coarse-grained parallelism and distributed shared
memory communication model implemented on a distributed memory architecture. It
differs from other languages of concurrent programming in the following:
concurrent processes are represented by packages which are semantically richer
entities than objects, inter-process communication is performed in terms of
classes, objects, scripts and packages, using the EDA communication model;
processes can be arranged into
structured collections: grids which enable to program data-parallel computations
on a high level; sequential segments of programs can be synthesized
automatically from specifications represented as classes using the program
synthesis features of NUT. Examples
of usage of generic parallel computing control structures PARDIF and PARARR are
given.
execution
models for a massively parallel
prolog implementation. Part I.
P.
Kacsuk
Abstract.
The
Generalized Dataflow Model is introduced for OR- and pipeline AND-parallel
execution of logic programs. A higher level abstraction of the dataflow model
called the Logicflow Model is applied to implement Prolog on massively parallel
distributed memory computers. Properties of the Logicflow Model concerning the
logic programming execution scheme are proved in detail. Based on the two
execution models the Distributed Data Driven Prolog Abstract Machine (3DPAM) can
be defined. It is shown how the 3DPAM
are derived from the dataflow and logicflow nodes in the case of alternative
clauses.
a workload
characterization by clustering technique
B.
Paternoster, M. Sessa
Abstract.
An
improvement of a method for the characterization of computer workload by means
of arrival patterns is presented. A numerical fitting technique provides a
suitable representation of the arrival rate function of jobs over one day
period. In order to classify such arrival patterns, we suggest the application
of the MacQueen algorithm with coarsening and refining parameters [2], which
does not need the number of clusters to be fixed a priori, as in the original
approach [4]. Solutions for some numerical problems related to the approximation
of the arrival rate function are also provided. The proposed technique has been
implemented and experimental results concerning the workload characterization of
an educational system are given.
An efficient algorithm
for testing propositional formulas
M.
Vlada
Abstract.
The
determinant of the Boolean Formulae a
= {C1,…,Cm} was introduced in [1]. The
present paper gives an algorithm for testing satisfiably propositional formulas.
The algorithm based on the enumeration of solutions for testing the
satisfiability of propositional formulas has already been given by Kazuo Iwama
[2]. The present paper is original by combining this algorithm
with other procedures, especially with the pure-literal rule and the
one-literal rule, and also the one which consists in changing any formulas in
bounded formulas. The algorithm based on the enumeration of the solution
combined to these procedures is more efficient.