4,153 research outputs found
State-of-the-art on evolution and reactivity
This report starts by, in Chapter 1, outlining aspects of querying and updating resources on
the Web and on the Semantic Web, including the development of query and update languages
to be carried out within the Rewerse project.
From this outline, it becomes clear that several existing research areas and topics are of
interest for this work in Rewerse. In the remainder of this report we further present state of
the art surveys in a selection of such areas and topics. More precisely: in Chapter 2 we give
an overview of logics for reasoning about state change and updates; Chapter 3 is devoted to briefly describing existing update languages for the Web, and also for updating logic programs;
in Chapter 4 event-condition-action rules, both in the context of active database systems and
in the context of semistructured data, are surveyed; in Chapter 5 we give an overview of some relevant rule-based agents frameworks
Distributed First Order Logic
Distributed First Order Logic (DFOL) has been introduced more than ten years
ago with the purpose of formalising distributed knowledge-based systems, where
knowledge about heterogeneous domains is scattered into a set of interconnected
modules. DFOL formalises the knowledge contained in each module by means of
first-order theories, and the interconnections between modules by means of
special inference rules called bridge rules. Despite their restricted form in
the original DFOL formulation, bridge rules have influenced several works in
the areas of heterogeneous knowledge integration, modular knowledge
representation, and schema/ontology matching. This, in turn, has fostered
extensions and modifications of the original DFOL that have never been
systematically described and published. This paper tackles the lack of a
comprehensive description of DFOL by providing a systematic account of a
completely revised and extended version of the logic, together with a sound and
complete axiomatisation of a general form of bridge rules based on Natural
Deduction. The resulting DFOL framework is then proposed as a clear formal tool
for the representation of and reasoning about distributed knowledge and bridge
rules
A Gentle Introduction to Epistemic Planning: The DEL Approach
Epistemic planning can be used for decision making in multi-agent situations
with distributed knowledge and capabilities. Dynamic Epistemic Logic (DEL) has
been shown to provide a very natural and expressive framework for epistemic
planning. In this paper, we aim to give an accessible introduction to DEL-based
epistemic planning. The paper starts with the most classical framework for
planning, STRIPS, and then moves towards epistemic planning in a number of
smaller steps, where each step is motivated by the need to be able to model
more complex planning scenarios.Comment: In Proceedings M4M9 2017, arXiv:1703.0173
Modal logics are coalgebraic
Applications of modal logics are abundant in computer science, and a large number of structurally different modal logics have been successfully employed in a diverse spectrum of application contexts. Coalgebraic semantics, on the other hand, provides a uniform and encompassing view on the large variety of specific logics used in particular domains. The coalgebraic approach is generic and compositional: tools and techniques simultaneously apply to a large class of application areas and can moreover be combined in a modular way. In particular, this facilitates a pick-and-choose approach to domain specific formalisms, applicable across the entire scope of application areas, leading to generic software tools that are easier to design, to implement, and to maintain. This paper substantiates the authors' firm belief that the systematic exploitation of the coalgebraic nature of modal logic will not only have impact on the field of modal logic itself but also lead to significant progress in a number of areas within computer science, such as knowledge representation and concurrency/mobility
Model Checking Social Network Models
A social network service is a platform to build social relations among people
sharing similar interests and activities. The underlying structure of a social
networks service is the social graph, where nodes represent users and the arcs
represent the users' social links and other kind of connections. One important
concern in social networks is privacy: what others are (not) allowed to know
about us. The "logic of knowledge" (epistemic logic) is thus a good formalism
to define, and reason about, privacy policies. In this paper we consider the
problem of verifying knowledge properties over social network models (SNMs),
that is social graphs enriched with knowledge bases containing the information
that the users know. More concretely, our contributions are: i) We prove that
the model checking problem for epistemic properties over SNMs is decidable; ii)
We prove that a number of properties of knowledge that are sound w.r.t. Kripke
models are also sound w.r.t. SNMs; iii) We give a satisfaction-preserving
encoding of SNMs into canonical Kripke models, and we also characterise which
Kripke models may be translated into SNMs; iv) We show that, for SNMs, the
model checking problem is cheaper than the one based on standard Kripke models.
Finally, we have developed a proof-of-concept implementation of the
model-checking algorithm for SNMs.Comment: In Proceedings GandALF 2017, arXiv:1709.0176
Applying Formal Methods to Networking: Theory, Techniques and Applications
Despite its great importance, modern network infrastructure is remarkable for
the lack of rigor in its engineering. The Internet which began as a research
experiment was never designed to handle the users and applications it hosts
today. The lack of formalization of the Internet architecture meant limited
abstractions and modularity, especially for the control and management planes,
thus requiring for every new need a new protocol built from scratch. This led
to an unwieldy ossified Internet architecture resistant to any attempts at
formal verification, and an Internet culture where expediency and pragmatism
are favored over formal correctness. Fortunately, recent work in the space of
clean slate Internet design---especially, the software defined networking (SDN)
paradigm---offers the Internet community another chance to develop the right
kind of architecture and abstractions. This has also led to a great resurgence
in interest of applying formal methods to specification, verification, and
synthesis of networking protocols and applications. In this paper, we present a
self-contained tutorial of the formidable amount of work that has been done in
formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial
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Learning from AI : new trends in database technology
Recently some researchers in the areas of database data modelling and knowledge representations in artificial intelligence have recognized that they share many common goals. In this survey paper we show the relationship between database and artificial intelligence research. We show that there has been a tendency for data models to incorporate more modelling techniques developed for knowledge representations in artificial intelligence as the desire to incorporate more application oriented semantics, user friendliness, and flexibility has increased. Increasing the semantics of the representation is the key to capturing the "reality" of the database environment, increasing user friendliness, and facilitating the support of multiple, possibly conflicting, user views of the information contained in a database
A Survey of Languages for Specifying Dynamics: A Knowledge Engineering Perspective
A number of formal specification languages for knowledge-based systems has been developed. Characteristics for knowledge-based systems are a complex knowledge base and an inference engine which uses this knowledge to solve a given problem. Specification languages for knowledge-based systems have to cover both aspects. They have to provide the means to specify a complex and large amount of knowledge and they have to provide the means to specify the dynamic reasoning behavior of a knowledge-based system. We focus on the second aspect. For this purpose, we survey existing approaches for specifying dynamic behavior in related areas of research. In fact, we have taken approaches for the specification of information systems (Language for Conceptual Modeling and TROLL), approaches for the specification of database updates and logic programming (Transaction Logic and Dynamic Database Logic) and the generic specification framework of abstract state machine
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