Prototyping Formal System Models with Active Objects

We propose active object languages as a development tool for formal system models of distributed systems. Additionally to a formalization based on a term rewriting system, we use established Software Engineering concepts, including software product lines and object orientation that come with extensive tool support. We illustrate our modeling approach by prototyping a weak memory model. The resulting executable model is modular and has clear interfaces between communicating participants through object-oriented modeling. Relaxations of the basic memory model are expressed as self-contained variants of a software product line. As a modeling language we use the formal active object language ABS which comes with an extensive tool set. This permits rapid formalization of core ideas, early validity checks in terms of formal invariant proofs, and debugging support by executing test runs. Hence, our approach supports the prototyping of formal system models with early feedback.Comment: In Proceedings ICE 2018, arXiv:1810.0205

Legal nature of the tasks and functions of the financial control of railway transport of Ukraine

The purpose of the article is to reveal the legal nature of tasks and functions of financial control of railway transport of Ukraine. Research results. The essence of state financial control has been studied. The peculiarities of financial control on the whole and in railway transport in particular are determined. The concepts of "financial control", "tasks of financial control", "functions of financial control" are clarified. Practical meaning. The main tasks and functions of state financial control in general and in rail transport specifically are established. Value/originality. It was determined that the functions of the state financial control of railway transport of Ukraine should be understood as a certain system of tasks and responsibilities assigned to authorized state bodies and services in order to ensure efficient and economical use of railway transport funds

Modular Analysis of Distributed Hybrid Systems using Post-Regions (Full Version)

We introduce a new approach to analyze distributed hybrid systems by a generalization of rely-guarantee reasoning. First, we give a system for deductive verification of class invariants and method contracts in object-oriented distributed hybrid systems. In a hybrid setting, the object invariant must not only be the post-condition of a method, but also has to hold in the post-region of a method. The post-region describes all reachable states after method termination before another process is guaranteed to run. The system naturally generalizes rely-guarantee reasoning of discrete object-oriented languages to hybrid systems and carries over its modularity to hybrid systems: Only one dL-proof obligation is generated per method. The post-region can be approximated using lightweight analyses and we give a general notion of soundness for such analyses. Post-region based verification is implemented for the Hybrid Active Object language HABS