Dieter Fensel

IS Journal 2009 Journal Article

It's a Streaming World! Reasoning upon Rapidly Changing Information

• Emanuele Della Valle
• Stefano Ceri
• Frank Van Harmelen
• Dieter Fensel

Data streams occur in modern applications such as sensor network monitoring, traffic engineering, RFID tags applications, telecom call recording, medical record management, financial applications, and clickstreams. On the Web, many sites distribute and present information in real-time streams. In many of these application areas, the ability to perform complex reasoning tasks that combine streaming data with evolving knowledge would be of great benefit. Stream reasoning—an unexplored, yet high-impact research area—is a new multidisciplinary approach that will build on the Semantic Web and provide the abstractions, foundations, methods, and tools required to integrate data streams and reasoning systems.

IS Journal 2008 Journal Article

Near-Term Prospects for Semantic Technologies

• V. Richard Benjamins
• John Davies
• Ricardo Baeza-Yates
• PETER MIKA
• Hugo Zaragoza
• Mark Greaves
• Jose Manuel Gomez-Perez
• Jesus Contreras

Tor the past few years, the Semantic Web has been enjoying significant investment, mostly through research but to a lesser extent through start-ups and commercial projects. A major topic of discussion is where we can see those investments' results, so I asked several experts to consider what semantic technology will accomplish in the near future. The experts are from academia, venture capitalist firms, and companies focused on semantic technology, telecommunication, and Web 2. 0.

IS Journal 2007 Journal Article

Semantic Web Services, Part 2

• David Martin
• John Domingue
• Amit Sheth
• Steve Battle
• Katia Sycara
• Dieter Fensel

In part 2 of this Trends & Controversies installment, we continue exploring the state of the art, current practices, and future directions for Semantic Web services. SWS aims to bring Semantic Web technology - for representing, sharing, and reasoning about knowledge - to bear in Web service contexts. The objective is to enable a fuller, more flexible automation of service provision and use and the construction of more powerful tools and methodologies for working with services.

KER Journal 1999 Journal Article

A software architecture for knowledge-based systems

• Dieter Fensel
• Rix Groenboom

The paper introduces a software architecture for the specification and verification of knowledge-based systems combining conceptual and formal techniques. Our focus is component-based specification enabling their reuse. We identify four elements of the specification of a knowledge-based system: a task definition, a problem-solving method, a domain model, and an adaptor. We present algebraic specifications and a variant of dynamic logic as formal means to specify and verify these different elements. As a consequence of our architecture we can decompose the overall specification and verification task of the knowledge-based systems into subtasks. We identify different subcomponents for specification and different proof obligations for verification. The use of the architecture in specification and verification improves understandability and reduces the effort for both activities. In addition, its decomposition and modularisation enables reuse of components and proofs. Therefore, a knowledge-based system can be built by combining and adapting different reusable components.

IJCAI Conference 1999 Conference Paper

UPML: A framework for knowledge system reuse

• Dieter Fensel
• V Richard Benjamins
• Enrico Motta
• Bob Wielinga

Problem-solving methods provide reusable architectures and components for implementing the reasoning part of knowledge-based systems. The Unified Problem-solving Method Development Language, UPML, has been developed to describe and implement such architectures and components and to facilitate their semiautomatic reuse and adaptation. In a nutshell, UPML is a framework for developing knowledge-intensive reasoning systems based on libraries of generic problem-solving components. The paper describes the components, architectural constraints, development guidelines, and tools provided by UPML. Our focus is hereby on the meta ontology that has been developed to formalize the architectural structure and elements of UPML.

ECAI Conference 1998 Conference Paper

An Architecture for Reusing Problem-Solving Components

• Dieter Fensel
• V. Richard Benjamins

ECAI Conference 1996 Conference Paper

Assumptions of Problem-Solving Methods and their Role in Knowledge Engineering

• V. Richard Benjamins
• Dieter Fensel
• Remco Straatman

ECAI Conference 1996 Conference Paper

MLPM: Defining a Semantics and Axiomatization for Specifying the Reasoning Process of Knowleged-based Systems

• Dieter Fensel
• Rix Groenboom

KER Journal 1995 Journal Article

Formal methods in knowledge engineering

• Frank Van Harmelen
• Dieter Fensel

Abstract This paper presents a general discussion of the role of formal methods in knowledge engineering. We give an historical account of the development of the field of knowledge engineering towards the use of formal methods. Subsequently, we discuss the pros and cons of formal methods. We do this by summarising the proclaimed advantages, and by arguing against some of the commonly heard objections against formal methods. We briefly summarise the current state of the art and discuss the most important directions that future research in this field should take. This paper presents a general setting for the other contributions in this issue of the journal, which each deal with a specific issue in more detail.

KER Journal 1995 Journal Article

Formal specification languages in knowledge and software engineering

• Dieter Fensel

Abstract During the last few years, a number of formal specification languages for knowledge-based systems (KBS) have been developed. Characteristics of such systems are a complex knowledge base and an inference engine which uses this knowledge to solve a given problem. Languages for KBS have to cover both these aspects. They have to provide a means to specify a complex and large amount of knowledge and they have to provide a means to specify the dynamic reasoning behaviour of a KBS. Nevertheless, KBS are just a specific type of software system. Therefore, it seems quite natural to compare formal languages for specifying KBS with formal languages which were developed by the software community for specifying software systems. That is the subject of this paper.

KER Journal 1994 Journal Article

A comparison of languages which operationalize and formalize KADS models of expertise

• Dieter Fensel
• Frank Van Harmelen

Abstract In the field of knowledge engineering, dissatisfaction with the rapid-prototyping approach has led to a number of more principled methodologies for the contruction of knowledge-based systems. Instead of immediately implementing the gathered and interpreted knowledge in a given implementation formalism according to the rapid-prototyping approach, many such methodologies centre around the notion of a conceptual model: an abstract, implementation independent description of the relevant problem solving expertise. A conceptual model should describe the task which is solved by the system and the knowledge which is required by it. Although such conceptual models more precisely, and operationally as a means for model evaluation. In this paper, we study a number of such formal and operational languages for specifying conceptual models. To enable a meaningful comparison of such languages, we focus on languages which are all aimed at the same underlying conceptual model, namely that from the KADS method for building KBS. We describe eight formal languages for KADS models of expertise, and compare these languages with respect to their modelling primitives, their semantics, their implementations and their applications, Future research issues in the area of formal and operational specification languages for KBS are identified as the result of studying these languages. The paper also contains an extensive bibliography of research in this area.