112 research outputs found
Mechanistic Behavior of Single-Pass Instruction Sequences
Earlier work on program and thread algebra detailed the functional,
observable behavior of programs under execution. In this article we add the
modeling of unobservable, mechanistic processing, in particular processing due
to jump instructions. We model mechanistic processing preceding some further
behavior as a delay of that behavior; we borrow a unary delay operator from
discrete time process algebra. We define a mechanistic improvement ordering on
threads and observe that some threads do not have an optimal implementation.Comment: 12 page
Transmission protocols for instruction streams
Threads as considered in thread algebra model behaviours to be controlled by
some execution environment: upon each action performed by a thread, a reply
from its execution environment -- which takes the action as an instruction to
be processed -- determines how the thread proceeds. In this paper, we are
concerned with the case where the execution environment is remote: we describe
and analyse some transmission protocols for passing instructions from a thread
to a remote execution environment.Comment: 13 page
Interface groups and financial transfer architectures
Analytic execution architectures have been proposed by the same authors as a
means to conceptualize the cooperation between heterogeneous collectives of
components such as programs, threads, states and services. Interface groups
have been proposed as a means to formalize interface information concerning
analytic execution architectures. These concepts are adapted to organization
architectures with a focus on financial transfers. Interface groups (and
monoids) now provide a technique to combine interface elements into interfaces
with the flexibility to distinguish between directions of flow dependent on
entity naming.
The main principle exploiting interface groups is that when composing a
closed system of a collection of interacting components, the sum of their
interfaces must vanish in the interface group modulo reflection. This certainly
matters for financial transfer interfaces.
As an example of this, we specify an interface group and within it some
specific interfaces concerning the financial transfer architecture for a part
of our local academic organization.
Financial transfer interface groups arise as a special case of more general
service architecture interfaces.Comment: 22 page
Robustness of Equations Under Operational Extensions
Sound behavioral equations on open terms may become unsound after
conservative extensions of the underlying operational semantics. Providing
criteria under which such equations are preserved is extremely useful; in
particular, it can avoid the need to repeat proofs when extending the specified
language.
This paper investigates preservation of sound equations for several notions
of bisimilarity on open terms: closed-instance (ci-)bisimilarity and
formal-hypothesis (fh-)bisimilarity, both due to Robert de Simone, and
hypothesis-preserving (hp-)bisimilarity, due to Arend Rensink. For both
fh-bisimilarity and hp-bisimilarity, we prove that arbitrary sound equations on
open terms are preserved by all disjoint extensions which do not add labels. We
also define slight variations of fh- and hp-bisimilarity such that all sound
equations are preserved by arbitrary disjoint extensions. Finally, we give two
sets of syntactic criteria (on equations, resp. operational extensions) and
prove each of them to be sufficient for preserving ci-bisimilarity.Comment: In Proceedings EXPRESS'10, arXiv:1011.601
Network algebra for synchronous dataflow
We develop an algebraic theory of synchronous dataflow networks. First, a
basic algebraic theory of networks, called BNA (Basic Network Algebra), is
introduced. This theory captures the basic algebraic properties of networks.
For synchronous dataflow networks, it is subsequently extended with additional
constants for the branching connections that occur between the cells of
synchronous dataflow networks and axioms for these additional constants. We
also give two models of the resulting theory, the one based on stream
transformers and the other based on processes as considered in process algebra.Comment: 24 page
Process algebra with strategic interleaving
In process algebras such as ACP (Algebra of Communicating Processes),
parallel processes are considered to be interleaved in an arbitrary way. In the
case of multi-threading as found in contemporary programming languages,
parallel processes are actually interleaved according to some interleaving
strategy. An interleaving strategy is what is called a process-scheduling
policy in the field of operating systems. In many systems, for instance
hardware/software systems, we have to do with both parallel processes that may
best be considered to be interleaved in an arbitrary way and parallel processes
that may best be considered to be interleaved according to some interleaving
strategy. Therefore, we extend ACP in this paper with the latter form of
interleaving. The established properties of the extension concerned include an
elimination property, a conservative extension property, and a unique expansion
property.Comment: 19 pages, this version is a revision of the published versio
Contradiction-tolerant process algebra with propositional signals
In a previous paper, an ACP-style process algebra was proposed in which
propositions are used as the visible part of the state of processes and as
state conditions under which processes may proceed. This process algebra,
called ACPps, is built on classical propositional logic. In this paper, we
present a version of ACPps built on a paraconsistent propositional logic which
is essentially the same as CLuNs. There are many systems that would have to
deal with self-contradictory states if no special measures were taken. For a
number of these systems, it is conceivable that accepting self-contradictory
states and dealing with them in a way based on a paraconsistent logic is an
alternative to taking special measures. The presented version of ACPps can be
suited for the description and analysis of systems that deal with
self-contradictory states in a way based on the above-mentioned paraconsistent
logic.Comment: 25 pages; 26 pages, occurrences of wrong symbol for bisimulation
equivalence replaced; 26 pages, Proposition 1 added; 27 pages, explanation of
the phrase 'in contradiction' added to section 2 and presentation of the
completeness result in section 2 improved; 27 pages, uniqueness result in
section 2 revised; 27 pages, last paragraph of section 8 revise
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