Formal language

About: Formal language is a research topic. Over the lifetime, 5763 publications have been published within this topic receiving 154114 citations.

Multilingual verbalization of ORM conceptual models and axiomatized ontologies

Abstract: Verbalization is the process of writing the semantics captured in axioms into natural language sentences, which enables domain experts (who are not trained to understand technical/formal languages) to be able to participate in the modeling and validation processes of their domain knowledge. We present a novel approach to support multilingual verbalization of logical theories, axiomatizations, and other specifications such as business rules. This engineering solution is demonstrated with the Object Role Modeling language and the ontology engineering tool DogmaModeler, although its underlying principles can be reused with other conceptual models and formal languages, such as Description Logics, to improve its understandability and usability by the domain expert. Our engineering solution for multilingual verbalization is characterized by its flexibility, extensibility and maintainability of the verbalization templates, which allow for easy augmentation with other languages than the 10 currently supported.

Abstract Syntax and Semantics of Visual Languages

Abstract: The effective use of visual languages requires a precise understanding of their meaning. Moreover, it is impossible to prove properties of visual languages like soundness of transformation rules or correctness results without having a formal language definition. Although this sounds obvious, it is surprising that only little work has been done about the semantics of visual languages, and even worse, there is no general framework available for the semantics specification of different visual languages. We present such a framework that is based on a rather general notion of abstract visual syntax. This framework allows a logical as well as a denotational approach to visual semantics, and it facilitates the formal reasoning about visual languages and their properties. We illustrate the concepts of the proposed approach by defining abstract syntax and semantics for the visual languages VEX, Show and Tell and Euler circles. We demonstrate the semantics in action by proving a rule for visual reasoning with Euler circles and by showing the correctness of a Show and Tell program.

Formal analysis of hardware requirements

Abstract: Formal languages are increasingly used to describe the functional requirements (specifications) of circuits. These requirements are used as a means to communicate design intent and as basis for verification. In both settings it is of utmost importance that the specifications are of high quality. However, formal requirements are seldom the object of validation, even though they can be hard to understand and interactions between them can be subtle. In this paper, we present techniques and guidelines to explore and assure the quality of a formal specification. We define a technique to interactively explore the semantics of a specification by simulating its behavior for user-defined scenarios. Furthermore, we define techniques to automatically check specifications against a set of user-provided assertions, which must be satisfied, and a set of possibilities, which must not be contradicted. The proposed techniques support the user in the iterative development and refinement of high-quality specifications.

The State Complexity of Two Combined Operations: Star of Catenation and Star of Reversal

Abstract: The state complexity of two combined operations, star of catenation and star of reversal, on regular languages is considered in this paper. Tight bounds are obtained for both combined operations. The results clearly show that the state complexity of a combined operation can be very different from the composition of the state complexities of its participating individual operations. A new approach for research in automata and formal language theory is also explained.

Generating embedded software from hierarchical hybrid models

Abstract: Benefits of high-level modeling and analysis are significantly enhanced if code can be generated automatically from a model such that the correspondence between the model and the code is precisely understood. For embedded control software, hybrid systems is an appropriate modeling paradigm because it can be used to specify continuous dynamics as well as discrete switching between modes. Establishing a formal relationship between the mathematical semantics of a hybrid model and the actual executions of the corresponding code is particularly challenging due to sampling and switching errors. In this paper, we describe an approach to compile the modeling language Charon that allows hierarchical specifications of interacting hybrid systems. We show how to exploit the semantics of Charon to generate code from a model in a modular fashion, and identify sufficient conditions on the model that guarantee the absence of switching errors in the compiled code. The approach is illustrated by compiling a model for coordinated motion of legs for walking onto Sony's AIBO robot.