The northeastern Black Sea redox zone: Hydrochemical structure and its temporal variability

Detailed studies of the vertical structure of hydrochemical parameters in the northeastern Black Sea near Gelendzhik are presented and discussed. This work is based on a set of systematic observations carried out in this region during R/V Akvanavt and R/V Ashamba cruises from 1997 to 2005 and also on data from previous studies from 1984 to 1997. The Black Sea region near Gelendzhik is far from the influences of the Bosporus input and Danube River inflow. Therefore, the vertical structure in this region is more stable compared to the western Black Sea and reflects integrated, rather than local, changes of the Black Sea. Seasonal variations in the distribution of chemical parameters at the redox interface are connected to seasonal variations in hydrophysical processes and organic matter production. In winter, maxima of organic phosphorus and urea were absent in the vicinity of the onset of hydrogen sulfide. The concentrations of nitrate were lower in winter than in summer. Winter mixing in the anticyclone eddies led to reduced vertical gradients in the redox layer and to the disappearance of an upper phosphate minimum. Study of the interannual dynamics of oxygen concentrations in the Cold Intermediate Layer and anoxic waters boundary in the density field position revealed climatic-scale changes that may be connected with changes in the North Atlantic Oscillation (NAO) index. © 2006 Elsevier Ltd. All rights reserved

Как разработать простое средство верификации систем реального времени

To verify real-time properties of UML statecharts one may apply a UPPAAL, toolbox for model checking of real-time systems. One of the most suitable ways to specify an operational semantics of UML statecharts is to invoke the formal model of Hierarchical Timed Automata. Since the model language of UPPAAL is based on Networks of Timed Automata one has to provide a conversion of Hierarchical Timed Automata to Networks of Timed Automata. In this paper we describe this conversion algorithm and prove that it is correct w.r.t. UPPAAL query language which is based on the subset of Timed CTL.Исследуется задача верификации систем реального времени (СРВ). Для описания СРВ удобно использовать диаграммы состояний UML с семантикой, определяемой иерархическими автоматами. Для верификации СРВ часто применяется средство UPPAAL, разработанное для проверки формул логики TCTL на сети временных автоматов. Основным результатом данной статьи является алгоритм трансляции иерархических автоматов в сеть временных автоматов и обоснование его корректности

Fine Structure of Vertical Density Distribution in the Black Sea and Its Relationship with Vertical Turbulent Exchange

This paper is concerned with the analysis of the long-term regular time series of current velocity and conductivity, temperature, and depth (CTD) profiles, measured with the moored autonomous profiler Aqualog over the upper part of the continental slope at a fixed geographical location in the Northeastern Black Sea. This study focuses on the fine structure of the density profiles to show that the fine-structure Cox number (C) is a power function of the Richardson number (Ri). A similar inverse power relationship with the same exponent was found earlier for the coefficient of vertical turbulent mass exchange (Kρ) and Ri. Based on those results, the analysis indicated a statistically significant correlation between C and Kρ, which suggests that the estimations of Kρ could be conducted from the CTD data only

On the Designing of Model Checkers for Real-Time Distributed Systems

To verify real-time properties of UML statecharts one may apply a UPPAAL, toolbox for model checking of real-time systems. One of the most suitable ways to specify an operational semantics of UML statecharts is to invoke the formal model of Hierarchical Timed Automata. Since the model language of UPPAAL is based on Networks of Timed Automata one has to provide a conversion of Hierarchical Timed Automata to Networks of Timed Automata. In this paper we describe this conversion algorithm and prove that it is correct w.r.t. UPPAAL query language which is based on the subset of Timed CTL

On the Designing of Model Checkers for Real-Time Distributed Systems

To verify real-time properties of UML statecharts one may apply a UPPAAL, toolbox for model checking of real-time systems. One of the most suitable ways to specify an operational semantics of UML statecharts is to invoke the formal model of Hierarchical Timed Automata. Since the model language of UPPAAL is based on Networks of Timed Automata one has to provide a conversion of Hierarchical Timed Automata to Networks of Timed Automata. In this paper we describe this conversion algorithm and prove that it is correct w.r.t. UPPAAL query language which is based on the subset of Timed CTL.</p