Fresh Water Resources in the Natura 2000 Pricop-Huta Certeze and Tisa Superioară Protected Areas

The Transcarpatic Basin which includes the Maramureş Basin (and within it the PHCTS area) is the largest intra-Carpathian lowland area, structured on a substrate with different geology, consisting in igneous rocks and crystalline schists, in the high areas and sandstones, conglomerates, marl, clay and sands in the central lower part. These features along with important rainfall amounts (up to 1800 mm in Ukrainian side) create conditions for a surplus in water resources budget, along with extreme hydrological events which are becoming very common. The average discharge values in PCHTS area go up to 40 l/s.km2 in high mountain area, while in the lowland space the values are around to 5 l/s.km2. Although, the surface water resource is plentiful its capitalization is facing serious problems due to pollution of various origins, from the one related to former mining activities, to those linked to the existence of human habitats which provides different residues. As for the underground water resource, the relatively impermeable substrate creates poor conditions for reserves accumulation and gives unfavorable chemical properties for accumulated water. Overall, water balance is in surplus with rainfall values nearly double compared to the drainage ones and aridity index values which barely exceed 0.5

The Lambek calculus with iteration: two variants

Formulae of the Lambek calculus are constructed using three binary connectives, multiplication and two divisions. We extend it using a unary connective, positive Kleene iteration. For this new operation, following its natural interpretation, we present two lines of calculi. The first one is a fragment of infinitary action logic and includes an omega-rule for introducing iteration to the antecedent. We also consider a version with infinite (but finitely branching) derivations and prove equivalence of these two versions. In Kleene algebras, this line of calculi corresponds to the *-continuous case. For the second line, we restrict our infinite derivations to cyclic (regular) ones. We show that this system is equivalent to a variant of action logic that corresponds to general residuated Kleene algebras, not necessarily *-continuous. Finally, we show that, in contrast with the case without division operations (considered by Kozen), the first system is strictly stronger than the second one. To prove this, we use a complexity argument. Namely, we show, using methods of Buszkowski and Palka, that the first system is $\Pi_1^0$-hard, and therefore is not recursively enumerable and cannot be described by a calculus with finite derivations

Monitoring Time Intervals

Run-time checking of timed properties requires to monitor events occurring within a specified time interval. In a distributed setting, working with intervals is complicated due to uncertainties about network delays and clock synchronization. Determining that an interval can be closed - i.e., that all events occurring within the interval have been observed - cannot be done without a delay. In this paper, we consider how an appropriate delay can be determined based on parameters of a monitoring setup, such as network delay, clock skew and clock rate. We then propose a generic scheme for monitoring time intervals, parameterized by the detection delay, and discuss the use of this monitoring scheme to check different timed specifications, including real-time temporal logics and rate calculations

A decision procedure for bisimilarity of generalized regular expressions.

Contains fulltext : 84383.pdf (publisher's version ) (Closed access)SBMF '2010, 8 november 201

Language Definitions as Rewrite Theories

(To appear in Springer LNCS)International audienceK is a formal framework for defining the operational semantics of programming languages. It includes software tools for compiling K language definitions to Maude rewrite theories, for executing programs in the defined languages based on the Maude rewriting engine, and for analyzing programs by adapting various Maude analysis tools. A recent extension to the K tool suite is an automatic transformation of language definitions that enables the symbolic execution of programs, i.e., the execution of programs with symbolic inputs. In this paper we investigate the theoretical relationships between K language definitions and their translations to Maude, between symbolic extensions of K definitions and their Maude encodings, and how the relations between K definitions and their symbolic extensions are reflected on their respective representations in Maude. These results show, in particular, how analyses performed with Maude tools can be formally lifted up to the original language definitions

A modular structural operational semantics for delimited continuations

It has been an open question as to whether the Modular Structural Operational Semantics framework can express the dynamic semantics of call/cc. This paper shows that it can, and furthermore, demonstrates that it can express the more general delimited control operators control and shift

Correct-by-construction implementation of runtime monitors using stepwise refinement

Runtime verification (RV) is a lightweight technique for verifying traces of computer systems. One challenge in applying RV is to guarantee that the implementation of a runtime monitor correctly detects and signals unexpected events. In this paper, we present a method for deriving correct-by-construction implementations of runtime monitors from high-level specifications using Fiat, a Coq library for stepwise refinement. SMEDL (Scenario-based Meta-Event Definition Language), a domain specific language for event-driven RV, is chosen as the specification language. We propose an operational semantics for SMEDL suitable to be used in Fiat to describe the behavior of a monitor in a relational way. Then, by utilizing Fiat\u27s refinement calculus, we transform a declarative monitor specification into an executable runtime monitor with a proof that the behavior of the implementation is strictly a subset of that provided by the specification. Moreover, we define a predicate on the syntax structure of a monitor definition to ensure termination and determinism. Most of the proof work required to generate monitor code has been automated

A Language-Independent Proof System for Mutual Program Equivalence

International audienceTwo programs are mutually equivalent if they both diverge or they end up in similar states. Mutual equivalence is an adequate notion of equivalence for programs written in deterministic languages. It is useful in many contexts, such as capturing the correctness of, program transformations within the same language, or capturing the correctness of compilers between two different languages. In this paper we introduce a language-independent proof system for mutual equivalence, which is parametric in the operational semantics of two languages and in a state-similarity relation. The proof system is sound: if it terminates then it establishes the mutual equivalence of the programs given to it as input. We illustrate it on two programs in two different languages (an imperative one and a functional one), that both compute the Collatz sequence.Deux programmes sont en équivalence mutuelle s'ils divergent tous les deux ou s'ils terminent dans des états similaires. L'équivalence mutuelle est une notion adéquate d'équivalence pour les programmes déterministes. Elle est utile dans divers contextes, parmi lesquels on peut citer la preuve de transformations de programmes dans un langage donné, et la preuve de compilateurs entre deux langages. Dans cet article nous introduisons un système déductif pour l'équivalence mutuelle, qui a comme paramètres les sémantiques opérationnelles de deux langages ainsi qu'une relation de similitude entre états des programmes. Le système déductif est correct: lorsqu'il termine, il démontre l'équivalence des programmes qui lui sont donnés en entrée. Nous l'illustrons sur deux programmes, appartenant à des langages différents : l'un impératif, l'autre fonctionnel, qui calculent la séquence de Collatz de deux manières différentes