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Showing papers on "Formal language published in 2013"


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TL;DR: This short note presents a new formal language, lambda dependency-based compositional semantics (lambda DCS) for representing logical forms in semantic parsing by eliminating variables and making existential quantification implicit.
Abstract: This short note presents a new formal language, lambda dependency-based compositional semantics (lambda DCS) for representing logical forms in semantic parsing. By eliminating variables and making existential quantification implicit, lambda DCS logical forms are generally more compact than those in lambda calculus.

146 citations


Journal ArticleDOI
01 Mar 2013
TL;DR: This work introduces a graph-based approach to the representation of evolving entities in space and time by making a distinction between filiation and spatial relationships between entities, while an extended relational database specification implements the spatio-temporal graph model.
Abstract: This work introduces a graph-based approach to the representation of evolving entities in space and time. At an abstract level, the model makes a distinction between filiation and spatial relationships between entities, while at the database level, it stores derivation relationships and determines continuation and spatial relationships in time. An extended relational database specification implements the spatio-temporal graph model. A formal language models integrity constraints that are inherent to the model and those that are semantic and application dependent. The satisfiability of these constraints is studied and an algorithm for checking consistency of spatio-temporal graph is provided. An experimental evaluation shows the potential of the model.

74 citations


Journal ArticleDOI
TL;DR: A formal language theory approach to improving the security aspects of protocol design and message-based interactions in complex composed systems and a formalization of an exploit development technique, the parse tree differential attack, made possible by the conception of the role of formal grammars in security.
Abstract: We present a formal language theory approach to improving the security aspects of protocol design and message-based interactions in complex composed systems. We argue that these aspects are responsible for a large share of modern computing systems' insecurity. We show how our approach leads to advances in input validation, security modeling, attack surface reduction, and ultimately, software design and programming methodology. We cite examples based on real-world security flaws in common protocols, representing different classes of protocol complexity. We also introduce a formalization of an exploit development technique, the parse tree differential attack, made possible by our conception of the role of formal grammars in security. We also discuss the negative impact unnecessarily increased protocol complexity has on security. This paper provides a foundation for designing verifiable critical implementation components with considerably less burden to developers than is offered by the current state of the art. In addition, it offers a rich basis for further exploration in the areas of offensive analysis and, conversely, automated defense tools, and techniques.

60 citations


Book ChapterDOI
26 Aug 2013
TL;DR: A Ptime algorithm is given to check whether two given regular languages are separable by a piecewise testable language, that is, whether a \(\mathcal{B}\Sigma_1(<) sentence can witness that the languages are disjoint.
Abstract: Separation is a classical problem asking whether, given two sets belonging to some class, it is possible to separate them by a set from another class. We discuss the separation problem for regular languages. We give a Ptime algorithm to check whether two given regular languages are separable by a piecewise testable language, that is, whether a \(\mathcal{B}\Sigma_1(<)\) sentence can witness that the languages are disjoint. The proof refines an algebraic argument from Almeida and the third author. When separation is possible, we also express a separator by saturating one of the original languages by a suitable congruence. Following the same line, we show that one can as well decide whether two regular languages can be separated by an unambiguous language, albeit with a higher complexity.

59 citations


Journal ArticleDOI
TL;DR: It is shown that inheritance, a core concept from object-oriented programming, is a possible solution for realizing composition of computer languages.

58 citations


Journal ArticleDOI
TL;DR: This paper presents a translation of the Mizar library into the OMDoc format (Open Mathematical Documents), an XML-based representation format for mathematical knowledge, and exemplifies interoperability by indexing the translated library in the MathWebSearch engine, which provides an “applicable theorem search” service (almost) out of the box.
Abstract: The Mizar Mathematical Library is one of the largest libraries of formalized and mechanically verified mathematics. Its language is highly optimized for authoring by humans. As in natural languages, the meaning of an expression is influenced by its (mathematical) context in a way that is natural to humans, but harder to specify for machine manipulation. Thus its custom file format can make the access to the library difficult. Indeed, the Mizar system itself is currently the only system that can fully operate on the Mizar library. This paper presents a translation of the Mizar library into the OMDoc format (Open Mathematical Documents), an XML-based representation format for mathematical knowledge. OMDoc is geared towards machine support and interoperability by making formula structure and context dependencies explicit. Thus, the Mizar library becomes accessible for a wide range of OMDoc-based tools for formal mathematics and knowledge management. We exemplify interoperability by indexing the translated library in the MathWebSearch engine, which provides an "applicable theorem search" service (almost) out of the box.

50 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a method for supporting the design of intelligent socio-technical systems, placing emphasis on different levels of formal characterization, with equal attention to both the analysis of concepts in a formal calculus independent of computational concerns, and the representation of concept in a machine-processable form, fully cognizant of implementation issues.
Abstract: The design of intelligent socio-technical systems calls for careful examination of relevant social and organizational concepts. We present a method for supporting this design process, placing emphasis on different levels of formal characterization, with equal attention to both the analysis of concepts in a formal calculus independent of computational concerns, and the representation of concepts in a machine-processable form, fully cognizant of implementation issues--a step in the method we refer to as principled operationalization. There are many tools (i.e. formal languages) that can be used to support the design method; we define and discuss criteria for evaluating such tools. We believe that, were the method proposed to be adopted, it would enhance the state-of-the-art in the systematic design and engineering of socio-technical systems, respecting the fundamentally interdisciplinary nature of those tasks, in both their theoretical and practical dimensions.

50 citations


Book ChapterDOI
08 Jul 2013
TL;DR: The MMT language as mentioned in this paper is a scalable representation and interchange language for formal mathematical knowledge that allows natural representations of the syntax and semantics of virtually all declarative languages while making MMT-based knowledge management services easy to implement.
Abstract: The MMT language has been developed as a scalable representation and interchange language for formal mathematical knowledge. It permits natural representations of the syntax and semantics of virtually all declarative languages while making Mmt-based MKM services easy to implement. It is foundationally unconstrained and can be instantiated with specific formal languages. The MMT API implements the MMT language along with multiple backends for persistent storage and frontends for machine and user access. Moreover, it implements a wide variety of Mmt-based knowledge management services. The API and all services are generic and can be applied to any language represented in MMT. A plugin interface permits injecting syntactic and semantic idiosyncrasies of individual formal languages.

49 citations


Journal ArticleDOI
TL;DR: A new, comprehensive approach for the validation of functional requirements of hybrid systems, where discrete components and continuous components are tightly intertwined, and is built on a new language, othello, which is expressive enough to represent various domains of interest, yet allowing efficient procedures for checking the satisfiability.
Abstract: Flaws in requirements may have unacceptable consequences in the development of safety-critical applications. Formal approaches may help with a deep analysis that takes care of the precise semantics of the requirements. However, the proposed solutions often disregard the problem of integrating the formalization with the analysis, and the underlying logical framework lacks either expressive power, or automation.We propose a new, comprehensive approach for the validation of functional requirements of hybrid systems, where discrete components and continuous components are tightly intertwined. The proposed solution allows to tackle problems of conversion from informal to formal, traceability, automation, user acceptance, and scalability.We build on a new language, othello which is expressive enough to represent various domains of interest, yet allowing efficient procedures for checking the satisfiability. Around this, we propose a structured methodology where: informal requirements are fragmented and categorized according to their role; each fragment is formalized based on its category; specialized formal analysis techniques, optimized for requirements analysis, are finally applied.The approach was the basis of an industrial project aiming at the validation of the European Train Control System (ETCS) requirements specification. During the project a realistic subset of the ETCS specification was formalized and analyzed. The approach was positively assessed by domain experts.

48 citations


Journal ArticleDOI
TL;DR: A progress report on how researchers in the rewriting logic semantics project are narrowing the gap between theory and practice in areas such as: modular semantic definitions of languages; scalability to real languages; support for real time; semantics of software and hardware modeling languages; and semantics-based analysis tools such as static analyzers, model checkers, and program provers.
Abstract: Rewriting logic is an executable logical framework well suited for the semantic definition of languages. Any such framework has to be judged by its effectiveness to bridge the existing gap between language definitions on the one hand, and language implementations and language analysis tools on the other. We give a progress report on how researchers in the rewriting logic semantics project are narrowing the gap between theory and practice in areas such as: modular semantic definitions of languages; scalability to real languages; support for real time; semantics of software and hardware modeling languages; and semantics-based analysis tools such as static analyzers, model checkers, and program provers.

47 citations


Journal ArticleDOI
TL;DR: This paper discusses research frontiers of membrane computing by presenting current open problems and research topics, together with the relevant background and motivation.
Abstract: This paper discusses research frontiers of membrane computing by presenting current open problems and research topics, together with the relevant background and motivation.

Journal ArticleDOI
TL;DR: A new paradigm for the formulation of aircraft trajectory computation and prediction processes is proposed, and a complete trajectory computation process is built as an engine composed through the smart interconnection of several engines.
Abstract: This paper proposes a new paradigm for the formulation of aircraft trajectory computation and prediction processes. Under this paradigm, an aircraft trajectory can be expressed at different levels of detail using a set of novel intent-related formal languages. These languages can be used for describing different aspects of aircraft motion or the resulting predicted trajectory, ranging from high-level restrictions imposed on the trajectory to details on how the aircraft will be operated at any specific instant. After defining the complete hierarchy of these formal languages, the concept of trajectory language processing engine is introduced. Every engine can perform automated modifications over a trajectory specified at different levels or at the same level considering the language hierarchy. Finally, several engine examples are described, and a complete trajectory computation process is built as an engine composed through the smart interconnection of several engines. Examples of executions of these automated processes are also included.

Journal ArticleDOI
TL;DR: This paper shows how language considerations would enable better authoring of time and interaction during programming/composing and how it addresses critical aspects of a musical performance in real-time and gives a formal semantics to model the possible behaviors of the system in terms of Parametric Timed Automata.
Abstract: With the advent and availability of powerful personal computing, the computer music research and industry have been focusing on real-time musical interactions between musicians and computers; delegating human-like actions to computers who interact with a musical environment. One common use-case of this kind is Automatic Accompaniment where the system is comprised of a real-time machine listening system that in reaction to recognition of events in a score from a human performer, launches necessary actions for the accompaniment section. While the real-time detection of score events out of live musicians' performance has been widely addressed in the literature, score accompaniment (or the reactive part of the process) has been rarely discussed. This paper deals with this missing component in the literature from a formal language perspective. We show how language considerations would enable better authoring of time and interaction during programming/composing and how it addresses critical aspects of a musical performance (such as errors) in real-time. We sketch the real-time features required by automatic musical accompaniment seen as a reactive system. We formalize the timing strategies for musical events taking into account the various temporal scales used in music. Various strategies for the handling of synchronization constraints and the handling of errors are presented. We give a formal semantics to model the possible behaviors of the system in terms of Parametric Timed Automata.

Proceedings ArticleDOI
11 Nov 2013
TL;DR: The findings suggest that learning operative ND might be easier, and that students can reach a significant understanding of this concept when it is introduced in the context of a programming course that deals with a non-deterministic programming language like the language of Live Sequence Charts (LSC).
Abstract: Non-determinism (ND) is a fundamental concept in computer science, and comes in two main flavors. One is the kind of ND that appears in automata theory and formal languages. The other, which we term operative, appears in non-deterministic programming languages and in the context of concurrent and distributed systems. We believe that it is important to teach the two types of ND, especially as ND has become a very prominent characteristic of computerized systems. Currently, students are mainly introduced to ND of the first type, which is known to be hard to teach and learn. Our findings suggest that learning operative ND might be easier, and that students can reach a significant understanding of this concept when it is introduced in the context of a programming course that deals with a non-deterministic programming language like the language of Live Sequence Charts (LSC). Based on that, we suggest teaching operative ND in the context of concurrent and distributed programming, a topic which is covered by a new knowledge area that was added in Computer Science Curricula 2013.

Journal Article
TL;DR: The main historical development is presented and the basics concepts of descriptional complexity from a general abstract perspective are addressed and the representation by two-way finite automata, multi-head finite Automata, and limited automata are considered.
Abstract: Formal languages can be described by several means. A basic question is how succinctly can a descriptional system represent a formal language in comparison with other descriptional systems? What is the maximal size trade-o when changing from one system to another, and can it be achieved? Here, we select some recent trends in the descriptional complexity of formal languages and discuss the problems, results, and open questions. In particular, we present the main historical development and address the basics concepts of descriptional complexity from a general abstract perspective. Then we consider the representation by two-way finite automata, multi-head finite automata, and limited automata in more detail. Finally, we discuss a few further topics in note form. The results presented are not proved but we merely draw attention to the overall picture and some of the main ideas involved.

Journal ArticleDOI
TL;DR: This paper proposes a novel approach for describing infinite afs using tools from formal language theory and shows that several decision and construction problems which are known to be polynomial time solvable in finite afs are decidable in the context of the proposed formalism.

Journal ArticleDOI
TL;DR: This work sheds some new light on the well-known question of generalization of rough sets and the axiomatization of approximation operators in terms of various types of binary relations.
Abstract: The computer certification of rough sets the translation in a way understandable by machines seems to be far beyond the test phase. To assure the feasibility of the approach, we try to encode selected problems within rough set theory and as the testbed of already developed foundations --and in the same time as a payoff of the established framework --we shed some new light on the well-known question of generalization of rough sets and the axiomatization of approximation operators in terms of various types of binary relations. We show how much the human work can be enhanced with the use of automatic tools, without loosing too much time for the translation. Although the syntax is understandable by the computer, it offers relative flexibility and expressive power of the formal language.

Journal ArticleDOI
TL;DR: A systematic review process to investigate the main digital libraries in the area and to document the phases of the study indicated that in some of the studies retrieved, manually created grammars were used to comply with a particular purpose.
Abstract: Grammars are widely used to describe string languages such as programming and natural languages and, more recently, biosequences. Moreover, since the 1980s grammars have been used in computer vision and related areas. Some factors accountable for this increasing use regard its relatively simple understanding and its ability to represent some semantic pattern models found in images, both spatially and temporally. The objective of this article is to present an overview regarding the use of syntactic pattern recognition methods in image representations in several applications. To achieve this purpose, we used a systematic review process to investigate the main digital libraries in the area and to document the phases of the study in order to allow the auditing and further investigation. The results indicated that in some of the studies retrieved, manually created grammars were used to comply with a particular purpose. Other studies performed a learning process of the grammatical rules. In addition, this article also points out still unexplored research opportunities in the literature.

Book ChapterDOI
01 Jul 2013
TL;DR: This paper proposes a formal validation & verification methodology for timing behaviors given with TADL2 as a mapping to the Clock Constraint Specification Language (CCSL), a formal language that implements the MARTE Time Model.
Abstract: It is critical to analyze characteristics of real-time embedded systems, such as timing behavior, early in the development. In the automotive domain, EAST-ADL is a concrete example of the model-based approach for the architectural modeling of real-time systems. The Timing Augmented Description Language v2 (TADL2) allows for the specification of timing constraints on top of EAST-ADL models. In this paper we propose a formal validation & verification methodology for timing behaviors given with TADL2. The formal semantics of the timing constraints is given as a mapping to the Clock Constraint Specification Language (CCSL), a formal language that implements the MARTE Time Model. Based on such a mapping, the validation is carried out by the simulation of TADL2 specifications. The simulation allows for a rapid prototyping of TADL2 specifications. The verification is performed based on a TADL2 mapping to timed automata modeling using the Uppaal model-checker. The whole process is illustrated on a Brake-By-Wire application.

Book
30 Jul 2013
TL;DR: Different methods of evaluating and formalizing simulation models are explored, enabling computer and industrial engineers, mathematicians, and students working with computer simulations to thoroughly understand the progression from simulation to product, improving the overall effectiveness of modeling systems.
Abstract: Models and simulations are an important first step in developing computer applications to solve real-world problems. However, in order to be truly effective, computer programmers must use formal modeling languages to evaluate these simulations. Formal Languages for Computer Simulation: Transdisciplinary Models and Applications investigates a variety of programming languages used in validating and verifying models in order to assist in their eventual implementation. This book will explore different methods of evaluating and formalizing simulation models, enabling computer and industrial engineers, mathematicians, and students working with computer simulations to thoroughly understand the progression from simulation to product, improving the overall effectiveness of modeling systems.

Journal ArticleDOI
TL;DR: In this paper, a hierarchy of fast-growing complexity classes for decision problems with non-elementary complexity is introduced, with complexities ranging from simple towers of exponentials to Ackermannian and beyond.
Abstract: We introduce a hierarchy of fast-growing complexity classes and show its suitability for completeness statements of many non elementary problems. This hierarchy allows the classification of many decision problems with a non-elementary complexity, which occur naturally in logic, combinatorics, formal languages, verification, etc., with complexities ranging from simple towers of exponentials to Ackermannian and beyond.

Journal ArticleDOI
TL;DR: AnaCon is presented, a proof-of-concept system where normative texts written in CNL are automatically translated into the formal language CL using the Grammatical Framework (GF), which is then analysed for normative conflicts by the CLAN tool, which gives counter-examples in cases where conflicts are found.

Journal ArticleDOI
TL;DR: This work provides a complete characterization of the complexity of the main computational problems related to such languages: nonemptiness, universality, containment, membership, as well as the problem of constructing NFAs capturing such languages.

Proceedings ArticleDOI
25 Jun 2013
TL;DR: It is shown that some classic questions in function analysis can become elegantly computable in the context of regular real analysis, and that the class of regular functions is quite rich, and includes functions that are highly challenging to encode using traditional symbolic notation.
Abstract: We initiate the study of regular real analysis, or the analysis of real functions that can be encoded by automata on infinite words. It is known that ω-automata can be used to represent {relations} between real vectors, reals being represented in exact precision as infinite streams. The regular functions studied here constitute the functional subset of such relations. We show that some classic questions in function analysis can become elegantly computable in the context of regular real analysis. Specifically, we present an automata-theoretic technique for reasoning about limit behaviors of regular functions, and obtain, using this method, a decision procedure to verify the continuity of a regular function. Several other decision procedures for regular functions-for finding roots, fix points, minima, etc.-are also presented. At the same time, we show that the class of regular functions is quite rich, and includes functions that are highly challenging to encode using traditional symbolic notation.

Proceedings Article
01 Aug 2013
TL;DR: This paper shows how factored finitestate representations of subregular language classes are identifiable in the limit from positive data by learners which are polytime iterative and optimal.
Abstract: This paper shows how factored finitestate representations of subregular language classes are identifiable in the limit from positive data by learners which are polytime iterative and optimal. These representations are motivated in two ways. First, the size of this representation for a given regular language can be exponentially smaller than the size of the minimal deterministic acceptor recognizing the language. Second, these representations (including the exponentially smaller ones) describe actual formal languages which successfully model natural language phenomenon, notably in the subfield of phonology.

Journal ArticleDOI
TL;DR: People acquired unconscious structural knowledge of both tonal retrogrades and inversion, and inversions were implicitly learnt more easily than retrogrades constraining the nature of the memory buffer in computational models of implicit learning.

Journal ArticleDOI
TL;DR: An information-theoretic notion, namely, (Shannon) information rate, is used to generalize common syntactic similarity metrics (like Hamming distance and longest common subsequences) between strings to ones between languages.

Book ChapterDOI
16 Sep 2013
TL;DR: It is argued that constraint programming solvers are more suitable than existing solvers for verification tools that have to solve string constraints, as they have a rich tradition of constraints for membership in formal languages.
Abstract: We improve an existing propagator for the context-free grammar constraint and demonstrate experimentally the practicality of the resulting propagator. The underlying technique could be applied to other existing propagators for this constraint. We argue that constraint programming solvers are more suitable than existing solvers for verification tools that have to solve string constraints, as they have a rich tradition of constraints for membership in formal languages.

Dissertation
13 Jun 2013
TL;DR: This thesis presents several theoretical results related to the choice calculus, such as an equivalence relation that supports semantics-preserving transformations of choice calculus expressions, and a type system for ensuring that an expression is well formed.
Abstract: approved: Martin Erwig In this thesis I present the choice calculus, a formal language for representing variation in software and other structured artifacts. The choice calculus is intended to support variation research in a way similar to the lambda calculus in programming language research. Specifically, it provides a simple formal basis for presenting, proving, and communicating theoretical results. It can serve as a common language of discourse for researchers working on different views of similar problems and provide a shared back end in tools. This thesis collects a large amount of work on the choice calculus. It defines the syntax and denotational semantics of the language along with modular language extensions that add features important to variation research. It presents several theoretical results related to the choice calculus, such as an equivalence relation that supports semantics-preserving transformations of choice calculus expressions, and a type system for ensuring that an expression is well formed. It also presents a Haskell DSEL based on the choice calculus for exploring the concept of variational programming. c © Copyright by Eric Walkingshaw June 13, 2013 All Rights Reserved The Choice Calculus: A Formal Language of Variation

BookDOI
18 Dec 2013
TL;DR: This book explores the direct relation of modern CALL (Computer-Assisted Language Learning) to aspects of natural language processing for theoretical and practical applications, and worldwide demand for formal language education and training that focuses on restricted or specialized professional domains.
Abstract: Explores the direct relation of modern CALL (Computer-Assisted Language Learning) to aspects of natural language processing for theoretical and practical applications, and worldwide demand for formal language education and training that focuses on restricted or specialized professional domains. Unique in its broad-based, state-of-the-art, coverage of current knowledge and research in the interrelated fields of computer-based learning and teaching and processing of specialized linguistic domains. The articles in this book offer insights on or analyses of the current state and future directions of many recent key concepts regarding the application of computers to natural languages, such as: authenticity, personalization, normalization, evaluation. Other articles present fundamental research on major techniques, strategies and methodologies that are currently the focus of international language research projects, both of a theoretical and an applied nature.