Debugging Process Algebra Specifications

International audienceDesigning and developing distributed and concurrent applications has always been a tedious and error-prone task. In this context, formal techniques and tools are of great help in order to specify such concurrent systems and detect bugs in the corresponding models. In this paper, we propose a new framework for debugging value-passing process algebra through coverage analysis. We illustrate our approach with LNT, which is a recent specification language designed for formally modelling concurrent systems. We define several coverage notions before showing how to instrument the specification without affecting original behaviors. Our approach helps one to improve the quality of a dataset of examples used for validation purposes, but also to find ill-formed decisions, dead code, and other errors in the specification. We have implemented a tool for automating our debugging approach, and applied it to several real-world case studies in different application areas

Stability of Asynchronously Communicating Systems

Recent software is mostly constructed by reusing and composing existing components. Software components are usually stateful and therefore described using behavioral models such as finite state machines. Asynchronous communication is a classic interaction mechanism used for such software systems. However, analysing communicating systems interacting asynchronously via reliable FIFO buffers is an undecidable problem. A typical approach is to check whether the system is bounded, and if not, the corresponding state space can be made finite by limiting the presence of communication cycles in behavioral models or by fixing buffer sizes. In this paper, we focus on infinite systems and we do not restrict the system by imposing any arbitrary bounds. We introduce a notion of stability and prove that once the system is stable for a specific buffer bound, it remains stable whatever larger bounds are chosen for buffers. This enables us to check certain properties on the system for that bound and to ensure that the system will preserve them whatever larger bounds are used for buffers. We also prove that computing this bound is undecidable but show how we succeed in computing these bounds for many typical examples using heuristics and equivalence checking

Generalizing Liouville-type Problems for Differential 1-Forms from Lq Spaces to Non-Lq Spaces

We obtain Liouville-type results for closed and p-pseudo-coclosed differential 1-forms ! with energy of lim inf r!1 1 r2 R B(x0;r) j!jqdv \u3c 1 (that is, 2-finite growth), which extends finite q-energy ( R M j!jqdv \u3c 1) in Lq spaces to infinite q-energy ( R M j!jqdv = 1) in non-Lq spaces. In particular, we recapture mathematicians\u27 vanishing results of Liouville- type theorem for ! with finite q-energy in Lq spaces. Our method in this paper provides a successful way to work on Liouville-type problems for differential forms with a variety of energy conditions in broad spaces

Manipulative Macrostrategies in English Dialogical Discourse

Мета статті–виокремити та охарактеризувати маніпулятивні макростратегії. Досягнення мети передбачає розв’язання таких завдань: виокремити маніпулятивні стратегії і тактики та дослідити їхні особливості; проаналізувати комплексне вживання маніпулятивних макростратегій. Об’єктом дослідження є англомовний діалогічний дискурс, який містить висловлення маніпулятивного характеру. Предметом дослідження є дискурсивні, комунікативні та прагматичні особливості маніпулятивних макростратегій. The article deals with the principles which determine the basic manipulative macrostrategies. The particularities of manipulative strategies and tactics are demonstrate

Quantifying the Parallelism in BPMN Processes using Model Checking

International audienceA business process is a set of structured, related activities that aims at fulfilling a specific organizational goal for a customer or market. An important metric when developing a business process is its degree of parallelism, i.e., the maximum number of tasks that are executable in parallel in that process. The degree of parallelism determines the peak demand on tasks, providing a valuable guide for the problem of resource allocation in business processes. In this paper, we investigate how to automatically measure the degree of parallelism for business processes, described using the BPMN standard notation. We first present a formal model for BPMN processes in terms of Labelled Transition Systems, which are obtained through process algebra encodings. We then propose an approach for automatically computing the degree of parallelism by using model checking techniques and dichotomic search. We implemented a tool for automating this check and we applied it successfully to more than one hundred BPMN processes

The Communicative and Pragmatic Level of Verbal Manipulation in English Dialogical discourse: Social Situation of the Examination in the Court (Gender Aspect)

Стаття присвячується аналізу комунікативно-прагматичного рівня мовленнєвої маніпуляції в англомовному діалогічному дискурсі. Соціальна ситуація судового допиту розглянута як типова соціальна ситуація, що провокує використання маніпулятивних стратегій і тактик. Особлива увага приділяється гендерному аспекту маніпулятивного впливу. The article deals with the analysis of the communicative and pragmatic level of verbal manipulation in English dialogical discourse. Social situation of the examination in the court is regarded as a typical social situation which provokes the usage of manipulative strategies and tactics. Dialogical manipulative situations have been revealed on the basis of their cognitive discursive and communicative pragmatic characteristics. K. Serazhym’s communicative model is taken as the basis for the simulating of the dialogical manipulative situation structure. The central components of the dialogical manipulative situation are an addresser, an addressee, a message, an addresser’s world, an addressee’s world, an imaginative world of an addresser, an imaginative world of an addressee, social situation (temporal and physical space of communication). Illustrative material shows that manipulative interaction may be provoked by certain local and temporal conditions of communication. Social situation of flirting (living environment) and social situation of the examination in the court (official environment) are typical social situations which are impossible without manipulative influence. Court discourse is traditionally considered to be a type of argumentative verbal influence. Following G. Lakoff and O.S. Lunyova’s point of view we consider court discourse as such that contains most of strategies and tactics of manipulation. Special attention is given to the gender aspect of manipulative influence. Men are appeared to be manipulators in all situations of the examination in the court. In our corpus studies a lawyer or public prosecutor is represented by this gender identity only. An addressee of manipulation is represented by both male and female gender identities

Лексикологія англійської мови: робоча програма нормативної навчальної дисципліни

Програма з курсу «Лексикологія англійської мови» ставить за мету висвітлення як традиційних, так і новітніх теоретичних і практичних проблем лексикології з точки зору наукових досягнень сучасного вітчизняного та зарубіжного мовознавства та формування в майбутніх педагогів основ наукового мислення з прицілом на використання матеріалів курсу в практиці викладання англійської мови в освітніх закладах різного типу. Вивчення лексикології передбачає оволодіння студентами теоретичними знаннями з розділів: етимологічний склад сучасної англійської мови, словотворення, мотивовані та немотивовані словосполучення, семасіологія, варіанти та діалекти англійської мови, лексикографія

Probabilistic Analysis of Predictability in Discrete Event Systems

International audiencePredictability is a key property allowing one to expect in advance the occurrence of a fault in a system based on its observed events. Existing works give a binary answer to the question of knowing whether a system is predictable or not. In this paper, we consider discrete event systems where probabilities of the transitions are available. We show how to take advantage of this information to perform a Markov chain based analysis and extract a variety of probability values that give a finer appreciation of the degree of predictability. This analysis is particularly important in case of non predictable systems. We consider a "light" analysis that focuses only on predictability as well as a "deep" analysis that handles in a uniform framework both predictability and diagnosability

Introducing Divergence for Infinite Probabilistic Models

Computing the reachability probability in infinite state probabilistic models has been the topic of numerous works. Here we introduce a new property called \emph{divergence} that when satisfied allows to compute reachability probabilities up to an arbitrary precision. One of the main interest of divergence is that our algorithm does not require the reachability problem to be decidable. Then we study the decidability of divergence for probabilistic versions of pushdown automata and Petri nets where the weights associated with transitions may also depend on the current state. This should be contrasted with most of the existing works that assume weights independent of the state. Such an extended framework is motivated by the modeling of real case studies. Moreover, we exhibit some divergent subclasses of channel systems and pushdown automata, particularly suited for specifying open distributed systems and networks prone to performance collapsing in order to compute the probabilities related to service requirements.Comment: 31 page