Bounded Model Checking for Parametric Timed Automata

Abstract. The paper shows how bounded model checking can be ap-plied to parameter synthesis for parametric timed automata with con-tinuous time. While it is known that the general problem is undecidable even for reachability, we show how to synthesize a part of the set of all the parameter valuations under which the given property holds in a model. The results form a complete theory which can be easily applied to parametric verification of a wide range of temporal formulae – we present such an implementation for the existential part of CTL −X. 1 Introduction and related work The growing abundance of complex systems in real world, and their presence in critical areas fuels the research in formal specification and analysis. One of the established methods in systems verification is model checking, where the system is abstracted into the algebraic model (e.g. various versions of Kripke structures

Metallographic analysis of selected cobalt-based alloys with carbon additive

In this paper an analysis of the microstructure of cobalt-based alloys used for implants with different chemical composition was held. Metallographic analysis was conducted using the methods of light microscopy and scanning electron microscopy. Characterization and description of the phases occurring in the investigated alloys was carried out using X-ray microanalysis, X-ray diffraction analysis and hardness measurements. The aim of this study was to determine the nature of the structure, chemical composition and its selected properties that affect their use application

Application of microtomography methods for determination of the structure of bioresorbable composites made with generative laser technology

Artykuł porusza zagadnienia związane z wykorzystaniem metod mikrotomografii komputerowej do badań struktury kompozytów bioresorbowalnych wytwarzanych przy pomocy generatywnej metody laserowej. Wytworzone materiały, o różnych kompozycjach, poddane zostały analizie struktury wewnętrznej tj. warstwowości, porowatości oraz obserwacji innych anomalii występujących po procesie wytwarzania.The article raises issues related to the use of methods of computer microtomography to study the structure of bioresorbable composites produced using generative laser technology. Materials of various compositions were subjected to examination of internal structure, ie. stratification, porosity and other anomalies arisen after processing

Model checking of java programs using networks of fadds

In the paper we present the current theoretical base of the J2FADD tool, which translates a Java program to a network of finite automata with discrite data (FADDs).The reason for building the tool is that to model check a concurrent program writ-ten in Java by means of the tools like Uppaal or VerICS (the module VerICS ), an automata model of the Java program must be build first. This is because these tools verify only systems modeled as networks of automata, in particular, systems modeled as networks of FADDs. We also make an attempt to evaluate the J2FADD tool by comparison of it with the two well known Java verification tools: Bandera and Java PathFinder

SAT-based searching for k-quasi-optimal runs in weighted timed automata

In the paper we are concerned with an optimal cost reachability problem for weighted timed automata, and we use a translation to SAT to solve the problem. In particular, we show how to find a run of length k ∈ IN that starts at the initial state and terminates at a state containing a target location, its total cost belongs to the interval [c,c+1), for some natural number c ∈ IN, and the cost of each other run of length k, which also leads from the initial state to a state containing the target location, is greater or equal to c. This kind of runs is called k-quasi-optimal. We exemplify the use of our solution to the mentioned problem by means of the air traffic control problem, and we provide some preliminary experimental results

Verifying RTECTL properties of a train controller systems

In the paper we deal with a classic concurrency problem - a faulty train controller system (FTC). In particular, we formalize it by means of finite automata, and consider several properties of the problem, which can be expressed as formulae of a soft real-time branching time temporal logic, called RTECTL. Further, we verify the RTECTL properties of FTC by means of SAT-based bounded model checking (BMC) method, and present the performance evaluation of the BMC method with respect to the considered problem. The performance evaluation is given by means of the running time and the memory used

A GPGPU–based simulator for prism: statistical verification of results of PMC

We describe a GPGPU–based Monte Carlo simulator integrated with Prism. It supports Markov chains with discrete or continuous time and a subset of properties expressible in PCTL, CSL and their variants extended with rewards. The simulator allows an automated statistical verification of results obtained using Prism’s formal methods

The influence of different composite mixtures (PLA/HA) manufactured with additive laser technology on the ability of S. aureus and P. aeruginosa to form biofilms

Staphylococcus aureus (Gram-positive coccus) and Pseudomonas aeruginosa (Gram-negative bacterium) are the leading etiologic agents of biofilm-related, life-threatening infections in patients after orthopaedic implantations. The aim of the present paper is to estimate the ability of these two bacterial strains to form a biofilm on bioresorbable composites manufactured from polylactide (PLA) and hydroxyapatite (HA) with the use of Selective Laser Sintering (SLS) method. Methods: Microbiological tests were conducted on two variants of a solid specimen made with additive laser technology. Samples with different content of hydroxyapatite were made, with appropriate manufacturing parameters to ensure stability of both composite ingredients. The geometry of samples was obtained by technical computed tomography. Microbiological tests determined the number of bacterial cells after incubation. Results: The results indicate significantly decreased ability of S. aureus and P. aeruginosa to form biofilms on the surface of materials with higher content of hydroxyapatite ceramics. Conclusions: The data may be useful for future applications of SLS technology in the production of bioresorbable PLA/HA medical implant