Daniil A. Zorin

Algorithm for synthesis of real-time systems under reliability constraints

The problem of constructing a real-time computing system that has a minimum number of processors is addressed. It is necessary that the system meets the deadlines of program execution and the system reliability requirements implying that the system must tolerate both hardware and software failures. The formal statement of this problem is presented, a method for its solution using an iterative scheduling algorithm based on the method of simulated annealing is proposed, and an experimental study of the proposed algorithm is conducted.

Co-design of Real-time Embedded Systems under Reliability Constraints

This paper describes a method of designing a computational system with the minimal number of processors. Strict execution deadlines apply, as well as restrictions on the reliability of the system that imply the tolerance of the system to both hardware and software faults. The problem is formulated mathematically, an algorithm of solution based on simulated annealing is described, and experimental results are shown.

Estimating the convergence of a simulated annealing algorithm for the problem of constructing multiprocessor schedules

An algorithm for constructing a computational system with the minimum number of processors while observing restrictions on system reliability and program execution time is considered. The problem is formulated mathematically, and an algorithm based on simulated annealing is proposed. Asymptotic convergence of the algorithm is formally proved.

Simulated Annealing Algorithm for Job Shop Scheduling on Reliable Real-Time Systems

This paper is devoted to the problem of designing a computational system utilizing the minimal number of processors to ensure that the program is executed before the deadline. The program is represented by a direct acyclic graph where vertices correspond to jobs. The system is supposed to tolerate both hardware and software faults. The schedule of the program execution does not include the exact moments of job launch and termination, thus allowing to employ abstract models with various levels of detail to estimate the time of execution. A simulated annealing algorithm is proposed for this problem. The paper provides the proof of asymptotic convergence of the algorithm and an experimental evaluation. The algorithm is also applied to a practical problem of scheduling in radiolocation systems.

Translation of UML Statecharts to UPPAAL Automata for Verification of Real-time Systems

In this paper we present a tool to transform UML statecharts to UPPAAL automata. The tool allows one to check temporal properties against statecharts modeling a real-time system. We give the constraints on statecharts, the tool description, and the results of testing it on a well-known traffic control example.

A combined toolset for the verification of real-time distributed systems

Checking the correctness of distributed systems is one of the most difficult and urgent problems in software engineering. A combined toolset for the verification of real-time distributed systems (RTDS) is described. RTDSs are specified as statecharts in the Universal Modeling Language (UML). The semantics of statecharts is defined by means of hierarchical timed automata. The combined toolset consists of a UML statechart editor, a verification tool for model checking networks of real-time automata in UPPAAL, and a translator of UML statecharts into networks of timed automata. The focus is on the translation algorithm from UML statecharts into networks of hierarchical timed automata. To illustrate the proposed approach to the verification of RTDSs, a toy example of a real-time crossroad traffic control system is analyzed.

Job Shop Scheduling and Co-Design of Real-Time Systems with Simulated Annealing

This paper describes a method of designing a computational system with the minimal number of processors. Strict execution deadlines apply, as well as restrictions on the reliability of the system that imply the tolerance of the system to both hardware and software faults. The problem is formulated mathematically, an algorithm of solution based on simulated annealing is described, and experimental results are shown.

Simulated annealing algorithm in problems of multiprocessor scheduling

An algorithm was proposed to simulate annealing for determination of the minimal necessary number of processors and construction of the static schedule for execution of the applied programs with allowance for the constraints on the time of schedule execution and reliability requirements. The developed algorithm was substantiated both theoretically and experimentally by comparing different laws of temperature decrease in the annealing simulation algorithm.

How to make a simple tool for verification of real-time 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.