Weak equivalence of higher-dimensional automata

This paper introduces a notion of equivalence for higher-dimensional automata, called weak equivalence. Weak equivalence focuses mainly on a traditional trace language and a new homology language, which captures the overall independence structure of an HDA. It is shown that weak equivalence is compatible with both the tensor product and the coproduct of HDAs and that, under certain conditions, HDAs may be reduced to weakly equivalent smaller ones by merging and collapsing cubes.

A corpus-based study of composite predicates in Early Modern English dialogues

Composite predicates (CPs), that is, complex predicate structures comprising a light verb and an eventive noun (e.g., make a move or give a speech) are common in Present-day English and are particularly characteristic of spoken language. The aim of the paper is to trace language changes involving CPs from 1560 to 1760, a period in which the use of CPs has not yet received adequate scholarly attention. Specifically, the study examines the frequencies, lexical productivity and syntactic patterns of CPs in two types of Early Modern English (EModE) dialogues, drawn from Trial Proceedings and Drama Comedy sampled in A Corpus of English Dialogues 1560–1760 – a 1.2-million word computerized corpus of EModE speech-related texts. The results reveal significant differences between the two types of dialogue and shed light on the development of CPs in association with grammaticalization and lexicalization.

Formal analysis of design process dynamics

This paper presents a formal analysis of design process dynamics. Such a formal analysis is a prerequisite to come to a formal theory of design and for the development of automated support for the dynamics of design processes. The analysis was geared toward the identification of dynamic design properties at different levels of aggregation. This approach is specifically suitable for component-based design processes. A complicating factor for supporting the design process is that not only the generic properties of design must be specified, but also the language chosen should be rich enough to allow specification of complex properties of the system under design. This requires a language rich enough to operate at these different levels. The Temporal Trace Language used in this paper is suitable for that. The paper shows that the analysis at the level of a design process as a whole and at subprocesses thereof is precise enough to allow for automatic simulation. Simulation allows the modeler to manipulate the specifications of the system under design to better understand the interlevel relationships in his design. The approach is illustrated by an example.

SPECIFICATION AND VERIFICATION OF DYNAMICS IN AGENT MODELS

Within many domains, among which biological, cognitive, and social areas, multiple interacting processes occur among agents with dynamics that are hard to handle. This paper presents the predicate logical Temporal Trace Language (TTL) for the formal specification and analysis of dynamic properties of agents and multi-agent systems. This language supports the specification of both qualitative and quantitative aspects, and therefore subsumes specification languages based on differential equations and qualitative, logical approaches. A software environment has been developed for TTL, which supports editing TTL properties and enables the formal verification of properties against a set of traces. The TTL environment proved its value in a number of projects within different biological, cognitive and social domains.

Mixed Script and Literacy in Korea

Today, Chinese characters (hanca) and Chinese-based Korean vocabulary (hancae or Sino-Korean) are either embraced or rejected as part of Korean identity. For more than a millennium, Koreans internalized Chinese belles lettres, making Chinese high culture a guiding light for gentlemen. Many Koreans today resent attitudes of satay ('serve the great') or mohwa ('adulate China'). However, others find this cynical self-image distorted or misguided. While the debate about mixed writing continues, the language will take its natural course. Since the "hankul only" policy was adopted in both Koreas, the need for continued use of Chinese has been felt, and policies have fluctuated. Nevertheless, Chinese � slowly coming to be seen as heavy, unclear, and perfunctory � is being abandoned. Hankul is there to stay, although it must keep "reforming" to trace language change. In today's global age, most South Koreans are no longer obsessed with independence. Mixed script with English or other European languages and logography in cyber writing may denote a contemporary educated people, despite strident voices from purists. Such mixed script constitutes an interesting new development in the Korean writing tradition. Whatever may evolve in both spoken and written Korean will be an important manifestation of national identity.

Determinizing Asynchronous Automata

A concurrent version of a finite-state automaton is a set of processes that cooperate in processing letters of the input. Each letter read prompts some of the processes to synchronize and decide on a joint move according to a non-deterministic transition relation. Such automata are known as <em>asynchronous automata</em>.<p> </p><p>The question whether these automata can be determinized while retaining the synchronization structure has already been answered is the positive, but indirectly, by Zielonka's Theorem. Unfortunately, this construction does not give an optimal solution.</p><p> </p><p>In this paper we present an elementary proof, which generalizes the classic subset construction for finite-state automata. The proof uses in an essential way an earlier finite-state construction by Mukund and Sohoni for maintaining each process's latest knowledge about other processes.</p><p> </p><p>Our construction is only double-exponential and thus is the first essentially to match the lower bound.</p><p> </p><p>In conjunction with earlier results of Ochmanski and Pighizzini, our construction provides a new (and in a sense ''classical'') proof of Zielonka's theorem that every recognizable trace language is accepted by a deterministic asynchronous automaton whose structure precisely captures the independence relation of the given trace alphabet.</p>

Behavioural Notions for Elementary Net Systems

We study the relationships between a number of behavioural notions that have arisen in the theory of distributed computing. In order to sharpen the understanding of these relationships we apply the chosen behavioural notions to a basic net-theoretic model of distributed systems called elementary net systems. The behavioural notions that are considered here are trace languages, non-sequential processes, unfoldings and event structures.<p>The relationships between these notions are brought out in the process of establishing that for each elementary net system, the trace language representation of its behaviour agrees in a strong way with the event structure representation of its behaviour.</p>