Papers by Wiktor B Daszczuk
Lecture notes in networks and systems, 2024
Computer Science and Information Systems (FedCSIS), 2019 Federated Conference on, Oct 10, 2023
Business process model and notation (BPMN) is a way of describing business processes using conven... more Business process model and notation (BPMN) is a way of describing business processes using convenient diagrams. In the last decade, it became a de-facto industry standard, widely used by software architects and business analysts to describe business requirements and the overall structure of a designed information system. Ensuring that diagrams model their intended behavior is of utmost importance for notation users. This article deals with the definition of BPMN through the conversion to the Integrated Model of Distributed Systems (IMDS) and automated verification of BPMN diagrams. The translation of a subset of BPMN preserves information about the processes in the formal model. This allows finding partial deadlocks and checking partial termination (concerning a subset of processes), verification in terms of BPMN processes, and mapping found errors onto source BPMN definition. Moreover, IMDS is tailored to model distributed systems, which is the very nature of business processes. A tool for automated translation of BPMN diagrams to IMDS, automated verification, and visualization of results is developed.
Lecture notes in networks and systems, 2023
Springer eBooks, 2022
There is a problem with arranging many elements in the window in many applications. It is more di... more There is a problem with arranging many elements in the window in many applications. It is more difficult when the elements are dynamically created or selected from a particular set. There is then a risk of obstruction by objects, which reduces the legibility of the window. Such a problem arises when generating dynamic help for items in a window in the workflow management system designed by Syndatis laboratories. Artificial intelligence algorithms can be used for this purpose, but the obstacle is their long calculations, which in the described case should be completed in less than a second. We proposed to use the evolutionary algorithm with a limited number of generations, which gives satisfactory results.
Studies in computational intelligence, Mar 17, 2019
Static deadlock detection methods suffer from space explosion problem. Model checking and other s... more Static deadlock detection methods suffer from space explosion problem. Model checking and other static analysis techniques are very effective in verification, many of them have a linear complexity to the size of the reachability space. However, the elaboration of the space is time-consuming (usually exponential) and takes a large amount of memory.
Energies
The ERTMS/ETCS is the newest automatic train protection system. This is a system that supports th... more The ERTMS/ETCS is the newest automatic train protection system. This is a system that supports the driver in driving the train. It is currently being implemented throughout the European Union. This system’s latest specifications also provide additional functions to increase the energy efficiency of train driving in the form of ATO (automatic train operation). These functions of the ETCS will be valuable, provided they operate without failure. To achieve errorless configuration of the ETCS, a methodology for automatic system verification using the IMDS (Integrated Model of Distributed Systems) formalism and the temporal tool Dedan was applied. The main contribution is asynchronous and timed verification, which appropriately models the distributed nature of the ETCS and allows the designer not only to analyze time dependencies but also to define the range of train velocities in which the operational scenario is valid. Additionally, the novelties of the presented verification methodolo...
Entropy
In building software architectures, the relations between elements in different diagrams are ofte... more In building software architectures, the relations between elements in different diagrams are often overlooked. The first stage of building IT systems is the use of ontology terminology, not software terminology, in the requirements engineering process. Then, when constructing software architecture, IT architects more or less consciously however introduce elements that represent the same classifier on different diagrams with similar names. These connections are called consistency rules and are usually not attached in any way in a modeling tool, and only a significant number of them in the models increase the quality of the software architecture. It is mathematically proved that the application of consistency rules increases the information content of software architecture. Authors show that increasing readability and ordering of software architecture by means of consistency rules have their mathematical rationale. In this article, we found proof of decreasing Shannon entropy while ap...
Energies
Relay-based traffic control systems are still used in railway control systems. Their correctness ... more Relay-based traffic control systems are still used in railway control systems. Their correctness is most often verified by manual analysis, which does not guarantee correctness in all conditions. Passenger safety, control reliability, and failure-free operation of all components require formal proof of the control system’s correctness. Formal evidence allows certification of control systems, ensuring that safety will be maintained in correct conditions and the in event of failure. The operational safety of systems in the event of component failure cannot be manually checked practically in the event of various types of damage to one component, pairs of components, etc. In the article, we describe the methodology of automated system verification using the IMDS (integrated model of distributed systems) temporal formalism and the Dedan tool. The novelty of the presented verification methodology lays in graphical design of the circuit elements, automated verification liberating the desig...
Annals of Computer Science and Information Systems
Abstract4Designing and implementing Web Services constitutes a large and constantly growing part ... more Abstract4Designing and implementing Web Services constitutes a large and constantly growing part of the information technology market. Web Services have specific scenarios in which distributed processes and network resources are used. This aspect of services requires integration with the model checkers. This article presents the experimentation framework in which services can be specified and then formally analyzed for deadlock-freedom, achievement of process goals, and similar features. Rybu4WS language enriches the basic Rybu language with the ability to use variables in processes, service calls between servers, new structural instructions, and other constructions known to programmers while remaining in line with declarative, mathematical IMDS formalism. Additionally, the development environment allows simulation of a counterexample or a witness -obtained as a result of the model checking -in a similar way to traditional debuggers.
Entropy, 2023
In building software architectures, the relations between elements in different diagrams are ofte... more In building software architectures, the relations between elements in different diagrams are often overlooked. The first stage of building IT systems is the use of ontology terminology, not software terminology, in the requirements engineering process. Then, when constructing software architecture, IT architects more or less consciously however introduce elements that represent the same classifier on different diagrams with similar names. These connections are called consistency rules and are usually not attached in any way in a modeling tool, and only a significant number of them in the models increase the quality of the software architecture. It is mathematically proved that the application of consistency rules increases the information content of software architecture. Authors show that increasing readability and ordering of software architecture by means of con-sistency rules have their mathematical rationale. In this article, we found proof of decreasing Shannon entropy while applying consistency rules in the construction of software architecture of IT systems. Therefore, it has been shown that marking selected elements in different diagrams with these same names is, therefore, an implicit way to increase the information content of software architecture while simultaneously improving its orderliness and readability. Moreover, this increase in the quality of the software architecture can be measured by entropy, which allows for checking whether the number of consistency rules is sufficient to compare different architectures, even of different sizes, thanks to entropy normalization, and checking during the development of the software architecture, what is the improvement in its orderliness and readability.
Energies, 2022
Relay-based traffic control systems are still used in railway control systems. Their correctness ... more Relay-based traffic control systems are still used in railway control systems. Their correctness is most often verified by manual analysis, which does not guarantee correctness in all conditions. Passenger safety, control reliability, and failure-free operation of all components require formal proof of the control system's correctness. Formal evidence allows certification of control systems, ensuring that safety will be maintained in correct conditions and the in event of failure. The operational safety of systems in the event of component failure cannot be manually checked practically in the event of various types of damage to one component, pairs of components, etc. In the article, we describe the methodology of automated system verification using the IMDS (integrated model of distributed systems) temporal formalism and the Dedan tool. The novelty of the presented verification methodology lays in graphical design of the circuit elements, automated verification liberating the designer from using temporal logic, checking partial properties related to fragments of the circuit, and fair verification preventing the discovering of false deadlocks. The article presents the verification of an exemplary relay traffic control system in the correct case, in the case of damage to elements, and the case of an incorrect sequence of signals from the environment. The verification results are shown in the form of sequence diagrams leading to the correct/incorrect final state.
Studies in Computational Intelligence, 2019
Communication duality, expressed as the server view and the agent view of the verified system, is... more Communication duality, expressed as the server view and the agent view of the verified system, is the sound effect of the author’s work. In the specification, it is simply grouping of actions in servers or in agents.
Studies in Computational Intelligence, 2019
The example of deadlock detection is presented for the system in which two distributed computatio... more The example of deadlock detection is presented for the system in which two distributed computations, each one running on its own server, use two semaphores.
Theory and Engineering of Dependable Computer Systems and Networks, 2021
Automated verification of distributed systems becomes very important in distributed computing. Th... more Automated verification of distributed systems becomes very important in distributed computing. The graphical insight into the system in the early and late stages of the project is essential. In the design phase, the visual input helps to articulate the collaborative distributed components clearly. The formal verification gives evidence of correctness or malfunction, but in the latter case, graphical simulation of counterexample helps for better understanding design errors. For these purposes, we invented Distributed Autonomous and Asynchronous Automata (DA 3), which have the same semantics as the formal verification base-Integrated Model of Distributed Systems (IMDS). The IMDS model reflects the natural characteristics of distributed systems: unicasting, locality, autonomy, and asynchrony. Distributed automata have all of these features because they share the same semantics as IMDS. In formalism, the unified system definition has two views: the server view of the cooperating distributed nodes and the agent view of the migrating agents performing distributed computations. The automata have two formally equivalent forms that reflect two views: Server DA 3 for observing servers exchanging messages, and Agent DA 3 for tracking agents, which visit individual servers in their progress of distributed calculations. We present the DA 3 formulation based on the IMDS formalism and their application to design and verify distributed systems in the Dedan environment. DA 3 formalism is compared with other concepts of distributed automata known from the literature.
2018 Baltic Geodetic Congress (BGC Geomatics), 2018
Autonomous Transit Network (ATN) is a public transport mode featuring automated vehicles operatin... more Autonomous Transit Network (ATN) is a public transport mode featuring automated vehicles operating on an elevated track. The quality of vehicle management algorithms, being a function of parameters of network operation, is measured as a time of waiting for a vehicle at a station. Recharging of vehicles creates additional factor which influences the quality of network behaviour. Previous papers analyse energy constraints in small ATN systems, with charging in capacitors or in stations. We propose a systematic analysis of ATN behaviour with energy constraints: more benchmarks are analysed and more charging manners are tested, including contactless power supply on the track. Some anomalies in network operation, resulting in rise of waiting time for cases with better charging possibility, are discussed.
The important feature of temporal model checking is the generation of counterexamples. In the rep... more The important feature of temporal model checking is the generation of counterexamples. In the report, the requirements for generation of counterexample (called critical tree) in model checking of CSM systems are described. The output of TempoRG model checker for QsCTL logic (a version of CTL) is presented. A contradiction between counterexample generation and state space reduction is commented.
In ICS, WUT a COSMA design environment is being developed. COSMA is based on Concurrent State Mac... more In ICS, WUT a COSMA design environment is being developed. COSMA is based on Concurrent State Machines (CSM) formalism of system specification. It contains a graphical tool for system design, various tools for the analysis (including a temporal model checker), simulator and code generator. In many projects, some common susbsystems take place. This concerns both complicated modules and simple counters. In the report, a concept of macrogeneration technique for building of libraries of automata is presented. The new technique will support a compactness of projects and reusability of modules.
Studies in Computational Intelligence, 2019
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Papers by Wiktor B Daszczuk
The author offers original formalism - Integrated Distributed Systems Model (IMDS) - combined with model checking based on temporal logic. The formalism allows the designer a specification that emphasizes the natural features of distributed systems and allows automatic verification of the typical features of such systems, such as deadlock and termination. The verified system is defined in a uniform model that can be observed in two general perspectives highlighting different aspects of the system. The server view involves servers’ states and message exchange. The agent view presents distributed agents traveling by means of messages and collaborating through shared resources.