Input Language Research Articles

Formal Verification of Object-Oriented Graph Grammars Specifications

Concurrent object-oriented systems are ubiquitous due to the importance of networks and the current demands for modular, reusable, and easy to develop software. However, checking the correctness of such systems is a hard task, mainly due to concurrency and inheritance aspects. In this paper we present an approach to the verification of concurrent object-oriented systems. We use graph grammars equipped with object oriented features (including inheritance and polymorphism) as the specification formalism, and define a translation from such specifications to Promela, the input language of the SPIN model checker.

The role of type and token frequency in using past tense morphemes correctly

Type and token frequency have been thought to be important in the acquisition of past tense morphology, particularly in differentiating regular and irregular forms. In this study we tested the role of frequency in two ways: (1) in bilingual children, who typically use and hear either language less often than monolingual children and (2) cross-linguistically: French and English have different patterns of frequency of regular/irregular verbs. Ten French-English bilingual children, 10 French monolingual and 10 English monolingual children between 4 and 6 years watched a cartoon and re-told the story. The results demonstrated that the bilingual children were less accurate than the monolingual children. Their accuracy in both French and English regular and irregular verbs corresponded to frequency in the input language. These results are consistent with the hypothesis that children learn past tense morphemes by analogy with other words in their vocabularies. We propose a developmental sequence based on conservative generalization across a growing set of verbs.

Korean putting verbs do not categorize space contrastively in terms of “tightness of fit”

The present study refutes Choi and Bowerman's (e.g. 1991) analysis of Korean putting verbs as showing a crosslinguistically unusual pattern of categorizing space in terms of “tightness of fit.” It shows that, in adult Korean, the differences between the “tight-fit” verb kki-ta (‘slide the Figure, which is surrounded by or surrounds the Ground, along the inner or outer side surface(s) of the Ground with friction produced between the side surfaces of the two objects’) and two “loose-fit” verbs, neh-ta (‘move the Figure to a locus where it is surrounded by the Ground’) and noh-ta (‘deposit the Figure by releasing one's hold of it and leave it the way it exists’), cannot be reduced to “tightness of fit”; in addition, they even show different syntactic behavior. First, the two types of verbs refer to different components and phases of a motion event. Neh-ta and noh-ta are path verbs that refer to the endpoint of a path, whereas kki-ta is a manner + path verb that focuses on an earlier phase; in particular, kki-ta normally requires the Figure and the Ground to produce friction in the course of the motion. Because of this difference, in a verb compound with the connective -e/- a, in which manner/cause verbs must precede path verbs, kki-ta occupies the manner/cause-verb slot, whereas neh-ta fills the path verb slot; noh-ta is usually used as an aspectual marker in the verb compound and goes into the final slot, after the above two slots. Despite Choi and Bowerman's argument for young children's acquisition of language-specific principles of categorization of the input language, their child subjects’ errors on their production of kki-ta show deviations from adult usage toward a much simpler pattern of categorizing putting events in terms of whether or not the Figure can easily be separated from the Ground at the endpoint of the path. The present study points out that the experimental studies conducted in recent years, which seem to show that preverbal infants respond categorically to putting events that appear to contrast in terms of “tightness of fit,” allow different interpretations, because the categorization principle that the infants used may not be based on “tightness of fit.”

Web Service Discovery and Composition for Virtual Enterprises

One main characteristic of virtual enterprises are short-term collaborations between business partners to provide efficient and individualized services to customers. The MOVE project targets at a methodology and a software framework to support such flexible collaborations based on process oriented design and communication by Web services. MOVE’s framework supports the graphical design and verification of business processes, the execution and supervision of processes in transaction-oriented environment, and the dynamic composition and optimization of processes. A business process may be composed from a set of Web services, deployed itself as Web service and executed in the framework. The composition of processes from Web services is implemented with methods from AI-planning. We apply answer set programming (ASP) and map Web service descriptions and customer requests into the input language of the ASP software DLV. Composition goals and constraints guide a composition challenge. We show the performance of our program and give some implementation details. Finally we conclude with some insights.

PROBABILISTIC TIMED AUTOMATA FOR MODELING NETWORKED AUTOMATION SYSTEMS

For the formal analysis of dependability of Networked Automation Systems (NAS) it is necessary to model the whole system first. Due to the probabilistic and distributed nature of the problem, a modular automata based approach is preferable for modeling and analysis. In this paper a formal automata definition for the specific needs of modeling NAS is given including continuous density distributions. For this model a discretization procedure as well as a transformation of the resulting discrete model into the input language of the probabilistic model checking software PRISM is presented. Finally an example is given, to illustrate the approach. The results of the automata based analysis are compared to measurements.

Efficient Integration of Pipelined IP Blocks into Automatically Compiled Datapaths

Compilers for reconfigurable computers aim to generate problem-specific optimized datapaths for kernels extracted from an input language. In many cases, however, judicious use of preexisting manually optimized IP blocks within these datapaths could improve the compute performance even further. The integration of IP blocks into the compiled datapaths poses a different set of problems than stitching together IPs to form a system-on-chip; though, instead of the loose coupling using standard busses employed by SoCs, the one between datapath and IP block must be much tighter. To this end, we propose a concise language that can be efficiently synthesized using a template-based approach for automatically generating lightweight data and control interfaces at the datapath level.

Infants’ use and weighting of prosodic cues in clause segmentation

This paper investigates the acoustic properties of speech used by infant listeners to discover clauses in continuous speech. In a series of experiments using the Headturn Preference procedure, 6-month-old infants’ use and weighting of prosodic cues in their segmentation of clauses in continuous speech was explored. The experiments sequentially featured each of three acoustic correlates of syntactic boundaries (pause duration, pitch, and preboundary lengthening) and examined whether infants’ performance on clause segmentation tasks remained the same or was degraded as the result of the loss of one or more of these correlates of a syntactic boundary. In this way, information concerning the perceptual weighting of these cues was elucidated. Results of these experiments suggest that while pitch is a necessary cue for 6-month-old English-learning infants, it is not a sufficient cue to segment clauses. Rather, the converging cues of pitch and pause or pitch and preboundary length are necessary. These results suggest that, although infants do not seem to weight these prosodic cues the same as adult listeners do, nonetheless, by 6 months of age they have already become attuned to some of the weighting of prosodic cues present in their input language and do not treat all cues equally.

Longest common subsequence problem for unoriented and cyclic strings

Given a finite set of strings X , the Longest Common Subsequence problem (LCS) consists in finding a subsequence common to all strings in X that is of maximal length. LCS is a central problem in stringology and finds broad applications in text compression, conception of error-detecting codes, or biological sequence comparison. However, in numerous contexts, words represent cyclic or unoriented sequences of symbols and LCS must be generalized to consider both orientations and/or all cyclic shifts of the strings involved. This occurs especially in computational biology when genetic material is sequenced from circular DNA or RNA molecules. In this work, we define three variants of LCS when the input words are unoriented and/or cyclic. We show that these problems are NP -hard, and W [ 1 ] -hard if parameterized in the number of input strings. These results still hold even if the three LCS variants are restricted to input languages over a binary alphabet. We also settle the parameterized complexity of our problems for most relevant parameters. Moreover, we study the approximability of these problems: we discuss the existence of approximation bounds depending on the cardinality of the alphabet, on the length of the shortest sequence, and on the number of input sequences. For this we prove that Maximum Independent Set in r -uniform hypergraphs is W [ 1 ] -hard if parameterized in the cardinality of the sought independent set and at least as hard to approximate as Maximum Independent Set in graphs.

An approximation algorithm for state minimization in 2-MDFAs

Abstract In this paper, we analyze the problem of state minimization in a class of Finite State Automata called Two Start State Deterministic Finite State Automata (2-MDFAs). A 2-MDFA is similar to a deterministic finite state automaton (DFA), in that on a given input, each state has precisely one destination state; however, it differs from a DFA in that there are two start states. A string is accepted by a 2-MDFA if and only if there exists a transitional path from either start state to a finish state, on that string . Observe that 2-MDFAs provide a limited amount of non-determinism and hence investigating their properties from the perspective of state minimization is a worthwhile pursuit. In case of unbounded non-determinism, i.e., Non-deterministic finite state automata (NFAs), it is well-known that the state minimization problem is PSPACE-complete [Jiang and Ravikumar in Proceedings of the 18th International Colloquium on Automata, Languages and Programming, ICALP’91, Madrid, Spain, July 8–12, 1991] and further that such automata can be exponentially more succinct than DFAs [Meyer and Fischer in Proceedings of the 12th SWAT(Annual Symposium on switching and automata theory), pp 188-191, 1971]. Even in the case of 2-MDFAs, the minimization problem remains non-trivial; indeed, Malcher in Theor Comput Sci 327(3):375–390, 2004 shows that the corresponding decision problem is NP-complete. We focus on deriving approximability bounds for the state minimization problem in 2-MDFAs. Our main contribution in the current paper, is the design of an n -approximation algorithm for state minimization in 2-MDFAs, where n denotes the minimum number of states required to represent the input language as a 2-MDFA. We also present a proof that this bound is tight for our algorithm.

Verifying Object-based Graph Grammars

The development of concurrent and reactive systems is gaining importance since they are well-suited to modern computing platforms, such as the Internet. However, the development of correct concurrent and reactive systems is a non-trivial task. Object-based graph grammar (OBGG) is a visual formal language suitable for the specification of this class of systems. In previous work, a translation from OBGG to PROMELA (the input language of the SPIN model checker) was defined, enabling the verification of OBGG models using SPIN. In this paper we extend this approach in two different ways: (1) the approach for property specification is improved, enabling to prove properties not only about possible OBGG derivations, but also about the internal state of involved objects; (2) an approach is defined to interpret PROMELA races as OBGG derivations, generating graphical counter-examples for properties that are not true for a given OBGG model. Another contribution of this paper is (3) the definition of a method for model checking partial systems (isolated objects or a set of objects) using an assume-guarantee approach. A gas station system modeled with OBGGs is used to illustrate the contributions.

The use of nouns and verbs by Japanese children and their caregivers in book-reading and toy-playing contexts

Japanese provides a valuable contrast for crosslinguistic studies of noun and verb dominance in early child language, and the effect of input on the early lexicon. In this study, 31 Japanese children between 1;0 and 2;0 and their caregivers were recorded in two contexts: joint bookreading and play with toys. Context had the largest effect, as nouns were much more frequent in the book context. Noun dominance was constant across development in the book context, but in the toy context there was a shift away as children developed from single words through the presyntactic stage to the syntactic stage. Caregiver language was verb dominant in a number of respects across development in the toy context, and thus was not closely related to child lexical balance. We conclude that in early lexical development, all children have a conceptual disposition to learn nouns. With vocabulary growth and the emergence of grammar, the proportion of verbs increases substantially, and at this stage properties of the input language may influence development.

Mad-X a worthy successor for MAD8?

MAD-X is the successor at CERN to MAD8, a program for accelerator design and simulation with a long history. We had to give up on MAD8 since the code had evolved in such a way that the maintenance and upgrades had become increasingly difficult. In particular, the memory management with the Zebra banks seemed outdated. MAD-X was first released in June, 2002. It offers most of the MAD8 functionality, with some additions, corrections, and extensions. The most important of these extensions is the interface to PTC, the Polymorphic Tracking Code by E. Forest. The most relevant new features of MAD-X are: languages: C, Fortran77, and Fortran90; dynamic memory allocation: in the core program written in C; strictly modular organization, modified and extended input language; symplectic and arbitrary exact description of all elements via PTC; Taylor Maps and Normal Form techniques using PTC. It is also important to note that we have adopted a new style for program development and maintenance that relies heavily on active maintenance of modules by the users themselves. Proposals for collaboration as with KEK, Japan and GSI, Germany are therefore very welcome.

A Verification Approach for GALS Integration of Synchronous Components

Starting with modules described in Signal synchronous programming language, we present an approach to verification of GALS systems. Since asynchronous parts of a GALS system can not be described in Signal, we use a mixture of synchronous descriptions in Signal and asynchronous descriptions in Promela. Promela is the input language to the SPIN asynchronous model checker. This allows us to achieve globally asynchronous composition (Promela) of locally synchronous components (Signal). Here we present three key results: first, we present a translation from Signal modules to Promela processes and prove their equivalence. Second, we present a technique to abstract a communication bus designed for GALS, the Loosely Time-Triggered Architecture (LTTA) bus, to a finite FIFO channel. The benefit of this abstraction is improved scalability for model checking larger specifications using SPIN. Third, we prove the trace equivalence of the model of the GALS system in Promela and a hardware implementation of it. This allows the verification of GALS systems based on the Promela model. We then use our technique to verify a central locking system for automobiles built on a GALS architecture using the LTTA.

Symbolic model checking of UML activity diagrams

Two translations from activity diagrams to the input language of NuSMV, a symbolic model verifier, are presented. Both translations map an activity diagram into a finite state machine and are inspired by existing statechart semantics. The requirements-level translation defines state machines that can be efficiently verified, but are a bit unrealistic since they assume the perfect synchrony hypothesis. The implementation-level translation defines state machines that cannot be verified so efficiently, but that are more realistic since they do not use the perfect synchrony hypothesis. To justify the use of the requirements-level translation, we show that for a large class of activity diagrams and certain properties, both translations are equivalent: regardless of which translation is used, the outcome of model checking is the same. Moreover, for linear stuttering-closed properties, the implementation-level translation is equivalent to a slightly modified version of the requirements-level translation. We use the two translations to model check data integrity constraints for an activity diagram and a set of class diagrams that specify the data manipulated in the activities. Both translations have been implemented in two tools. We discuss our experiences in applying both translations to model check some large example activity diagrams.

The Strength of the Weak: Asynchronies in the Simultaneous Acquisition of German and English

Children growing up with more than one first language present us with a unique opportunity for raising questions about language acquisition which we could hardly answer on the basis of monolingual data alone. In our contribution we will take a close look at developmental asynchronies, i.e. cases where one of the child’s languages develops faster than the other. On the basis of a longitudinal study involving English and German as first languages, we will show what asynchronies can teach us about the relative complexity of a child’s two input languages. In addition, we will identify clever learner strategies (language mixing, the employment of cross-linguistic placeholders, discourse borrowing) that provide us with interesting insights into bilingual children’s metalinguistic awareness of gaps in one of their linguistic systems.

Analyzing a χ model of a turntable system using Spin, CADP and Uppaal

Nowadays, due to increasing system complexity and growing competition and costs, industry makes high demands on powerful techniques used to design and analyze manufacturing systems. One of the most popular techniques to do performance analysis is simulation. However, simulation-based analysis cannot guarantee the correctness of a system, so it is less suitable for functional analysis. Our research focuses on examining other methods to do performance analysis and functional analysis, and trying to combine the two. One of the approaches is to translate a simulation model that is used for performance analysis to a model written in an input language of an existing verification tool. We translate a χ [D.A. van Beek, K.L. Man, M.A. Reniers, J.E. Rooda, R.R.H. Schiffelers, Syntax and Consistent Equation Semantics of Hybrid Chi, CS-Report 04-37, Eindhoven University of Technology, 2004] simulation model of a turntable system into models written in the input languages of the tools CADP [J.-C. Fernandez, H. Garavel, A. Kerbrat, L. Mounier, R. Mateescu, M. Sighireanu, CADP—a protocol validation and verification toolbox, in: Proceedings of the 8th Conference on Computer Aided Verification (CAV’96), Lecture Notes in Computer Science, vol. 1102, 1996, pp. 437–440], S pin [G.J. Holzmann, The SPIN Model Checker, Addison-Wesley, 2003] and U ppaal [K.G. Larsen, P. Pettersson, W.Yi, Uppaal in a nutshell, Int. J. Software Tools for Technology Transfer 1 (1–2) (1997) 134–152] and do a functional analysis with each of them. This allows us to evaluate the usefulness of these tools for the functional analysis of χ models. We compare the input formalisms, the expressiveness of the temporal logics, and the algorithmic techniques for model checking that are used in those tools.

Machine translation challenges for Portuguese

This paper addresses some of the central problems facing MT today. It points out a few areas where MT is failing, particularly in regards to the English-Portuguese (E-P) language pair. Finally it discusses the essence of MT evaluation: the linguistic criteria of the correspondence between the input and output languages, with examples on POS ambiguity and cross-language phenomena.

“Teacher English”: Teacher’s Target Language Use as Cornerstone of Successful Language Teaching

In most of today’s courses of English as a foreign language, the learners and teacher share the same mother tongue, but English is the language used to carry out all activities as far as the learner level allows. This means that the teacher’s level of target language mastery plays a significant role in the quality of language teaching and the resulting learning. The paper looks at the functions of teacher talk as a source of input and model language use as well as a tool for managing classroom processes. Based on that, an argument is made for ‘teacher English’ as a case of English for specific purposes.

Extracting finite structure from infinite language

This paper presents a novel connectionist memory-rule based model capable of learning the finite-state properties of an input language from a set of positive examples. The model is based upon an unsupervised recurrent self-organizing map with laterally interconnected neurons. A derivation of functional-equivalence theory is used that allows the model to exploit similarities between the future context of previously memorized sequences and the future context of the current input sequence. This bottom-up learning algorithm binds functionally related neurons together to form states. Results show that the model is able to learn the Reber grammar perfectly from a randomly generated training set and to generalize to sequences beyond the length of those found in the training set. ed sequences and the future context of the current input sequence. This bottom-up learning algorithm binds functionally related neurons together to form states. Results show that the model is able to learn the Reber grammar [A. Cleeremans, D. Schreiber, J. McClelland, Finite state automata and simple recurrent networks, Neural Computation, 1 (1989) 372-381] perfectly from a randomly generated training set and to generalize to sequences beyond the length of those found in the training set.

Maternal Correlates of Growth in Toddler Vocabulary Production in Low‐Income Families

This study investigated predictors of growth in toddlers' vocabulary production between the ages of 1 and 3 years by analyzing mother–child communication in 108 low‐income families. Individual growth modeling was used to describe patterns of growth in children's observed vocabulary production and predictors of initial status and between‐person change. Results indicate large variation in growth across children. Observed variation was positively related to diversity of maternal lexical input and maternal language and literacy skills, and negatively related to maternal depression. Maternal talkativeness was not related to growth in children's vocabulary production in this sample. Implications of the examination of longitudinal data from this relatively large sample of low‐income families are discussed.