328,849 research outputs found
A Little Bit Infinite? On Adding Data to Finitely Labelled Structures (Abstract)
Finite or infinite strings or trees with labels from a finite alphabet play an important role
in computer science. They can be used to model many interesting objects including system
runs in Automated Verification and XML documents in Database Theory. They allow the
application of formal tools like logical formulas to specify properties and automata for their
implementation. In this framework, many reasoning tasks that are undecidable for general
computational models can be solved algorithmically, sometimes even efficiently.
Nevertheless, the use of finitely labelled structures usually requires an early abstraction
from the real data. For example, theoretical research on XML processing very often con-
centrates on the document structure (including labels) but ignores attribute or text values.
While this abstraction has led to many interesting results, some aspects like key or other
integrity constraints can not be adequately handled.
In Automated Verification of software systems or communication protocols, infinite
domains occur even more naturally, e.g., induced by program data, recursion, time, com-
munication or by unbounded numbers of concurrent processes. Usually one approximates
infinite domains by finite ones in a very early abstraction step.
An alternative approach that has been investigated in recent years is to extend strings
and trees by (a limited amount of) data and to use logical languages with a restricted ex-
pressive power concerning this data. As an example, in the most simple setting, formulas
can only test equality of data values. The driving goal is to identify logical languages and
corresponding automata models which are strong enough to describe interesting proper-
ties of data-enhanced structures while keeping decidability or even feasibility of automatic
reasoning.
The talk gives a basic introduction into data-enhanced finitely labelled structures,
presents examples of their use, and highlights recent decidability and complexity results
Aircraft systems architecting: a functional-logical domain perspective
Presented is a novel framework for early systems architecture design. The framework defines data structures and algorithms that enable the systems architect to operate interactively and simultaneously in both the functional and logical domains. A prototype software tool, called AirCADia Architect, was implemented, which allowed the framework to be evaluated by practicing aircraft systems architects. The evaluation confirmed that, on the whole, the approach enables the architects to effectively express their creative ideas when synthesizing new architectures while still retaining control over the process
PDDL2.1: An extension of PDDL for expressing temporal planning domains
In recent years research in the planning community has moved increasingly towards application of planners to realistic problems involving both time and many types of resources. For example, interest in planning demonstrated by the space research community has inspired work in observation scheduling, planetary rover ex ploration and spacecraft control domains. Other temporal and resource-intensive domains including logistics planning, plant control and manufacturing have also helped to focus the community on the modelling and reasoning issues that must be confronted to make planning technology meet the challenges of application. The International Planning Competitions have acted as an important motivating force behind the progress that has been made in planning since 1998. The third competition (held in 2002) set the planning community the challenge of handling time and numeric resources. This necessitated the development of a modelling language capable of expressing temporal and numeric properties of planning domains. In this paper we describe the language, PDDL2.1, that was used in the competition. We describe the syntax of the language, its formal semantics and the validation of concurrent plans. We observe that PDDL2.1 has considerable modelling power --- exceeding the capabilities of current planning technology --- and presents a number of important challenges to the research community
Paving the Road to Business Process Administration
Event-driven Process Chains (EPCs) have been helped to achieve an important role in business process modeling by the commercial success of SAP and ARIS. Both users and IT experts may describe the process to be modelled from their individual perspectives. Event-driven Process Chains, therefore, create a common platform for communication and the analysis of ideas beyond the boundaries of both application and information-system domains. This is accomplished by a semiformal semantics, which gives the participants greater freedom of expression but leads to unintended ambiguities clearly undesirable in later stages of development such as design and implementation. In the literature, several approaches to this problem have been suggested including definitions of a formal semantics for EPCs. We investigate difficulties with such approaches and suggest two solutions: the introduction of a new logical connector (XORAND) and a slight modification of the OR join. This facilitates the design of correct EPCs while continuing to allow freedom of expression, thus enabling a smoother transition into the more formal phases of software development such as design and implementation. A comparative experiment validates these results
Buying Logical Principles with Ontological Coin: The Metaphysical Lessons of Adding epsilon to Intuitionistic Logic
We discuss the philosophical implications of formal results showing the con-
sequences of adding the epsilon operator to intuitionistic predicate logic. These
results are related to Diaconescuās theorem, a result originating in topos theory
that, translated to constructive set theory, says that the axiom of choice (an
āexistence principleā) implies the law of excluded middle (which purports to be
a logical principle). As a logical choice principle, epsilon allows us to translate
that result to a logical setting, where one can get an analogue of Diaconescuās
result, but also can disentangle the roles of certain other assumptions that are
hidden in mathematical presentations. It is our view that these results have not
received the attention they deserve: logicians are unlikely to read a discussion
because the results considered are āalready well known,ā while the results are
simultaneously unknown to philosophers who do not specialize in what most
philosophers will regard as esoteric logics. This is a problem, since these results
have important implications for and promise signif i cant illumination of contem-
porary debates in metaphysics. The point of this paper is to make the nature
of the results clear in a way accessible to philosophers who do not specialize in
logic, and in a way that makes clear their implications for contemporary philo-
sophical discussions. To make the latter point, we will focus on Dummettian discussions of realism and anti-realism.
Keywords: epsilon, axiom of choice, metaphysics, intuitionistic logic, Dummett,
realism, antirealis
Formal Concept Analysis and Resolution in Algebraic Domains
We relate two formerly independent areas: Formal concept analysis and logic
of domains. We will establish a correspondene between contextual attribute
logic on formal contexts resp. concept lattices and a clausal logic on coherent
algebraic cpos. We show how to identify the notion of formal concept in the
domain theoretic setting. In particular, we show that a special instance of the
resolution rule from the domain logic coincides with the concept closure
operator from formal concept analysis. The results shed light on the use of
contexts and domains for knowledge representation and reasoning purposes.Comment: 14 pages. We have rewritten the old version according to the
suggestions of some referees. The results are the same. The presentation is
completely differen
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