Attila Klenik

Budapest University of Technology and Economics · Department of Measurement and Information Systems

Smart contracts in blockchains often implement critical functionality; consequently, their development time software fault detection, removal, and avoidance have been the target of intensive research. However, the applicability of runtime dependability mechanisms to smart contracts has not been explored systematically, mainly due to the transaction...

The execute-order-validate approach to blockchain consensus, most notably implemented by Hyperledger Fabric, facilitates highly scalable execution of smart contract – in Fabric terminology, ”chaincode” – invocations in cross-organizational blockchains; at the expense of requiring multi-version concurrency control conflict handling during block vali...

The design and operation of modern software systems exhibit a shift towards virtualization, containerization and service-based orchestration. Performance capacity engineering and resource utilization tuning become priority requirements in such environments. Measurement-based performance evaluation is the cornerstone of capacity engineering and desi...

The design and operation of modern software systems exhibit a shift towards virtualization, containerization and service-based orchestration. Performance capacity engineering and resource utilization tuning become priority requirements in such environments. Measurement-based performance evaluation is the cornerstone of capacity engineering and desi...

Many cross-organization cooperation applications of blockchain-based distributed ledger technologies (DLT) do not aim at innovation at the cooperation pattern level: essentially the same ''business'' is conducted by the parties, but this time without a central party to be trusted with bookkeeping. The migration to DLT is expected to have a negative...

Blockchain has become particularly popular due to its promise to support business-critical services in very different domains (e.g., retail, healthcare). Blockchain systems rely on complex middleware, like Ethereum or Hyperledger Fabric, that allow running smart contracts, which specify business logic in cooperative applications. The presence of so...

Blockchain has become particularly popular due to its promise to support business-critical services in very different domains (e.g., retail, supply chains, healthcare). Blockchain systems rely on complex middleware, like Ethereum or Hyperledger Fabric, that allow running smart contracts, which specify business logic in cooperative applications. The...

Cyber-physical systems frequently perform measurement and control of safety-critical applications. Collecting data for a posteriori analysis in hazardous and or catastrophic situations is of crucial importance both for investigations and effective measures aiming at avoidance of a recurrence of such events. At the same time, damage confinement and...

After the success of bitcoin proved the viability of the distributed ledger technology, other frameworks emerged with the goal of providing a general purpose blockchain platform for businesses to execute smart contracts. The private and permissioned platforms are promising replacements for many current systems in several sectors, such as finance, h...

Timeliness and throughput critical applications require a framework offering predictable temporal characteristics. The best practice for estimating a prediction of the system dynamics relies on benchmarking. Each novel middleware solution needs such an evaluation as part of the development process to assure an appropriate throughput in the future u...

Since their invention, Petri nets have provided modelling and analysis methods to support the design of correct, reliable and robust systems. This motivated our work to develop PetriDotNet, a Petri net editor and analysis tool. In this paper we overview the supported modelling formalisms and the analysis methods included in PetriDotNet. Next, we pr...

Blockchain technologies target domains where strict performance guarantees are required and formal Service Level Agreements are commonplace. Designing for performance targets in a trustworthy manner requires performance models; we present a performance characterization approach that addresses the complexity of Blockhain technologies. We apply the m...

Stochastic Petri nets are widely used for the modeling and analysis of non-functional properties of critical systems. The state space explosion problem often inhibits the numerical analysis of such models. Symbolic techniques exist to explore the discrete behavior of even complex models, while block Kronecker decomposition provides memory-efficient...

PetriDotNet is an extensible Petri net editor and analysis tool originally developed to support the education of formal methods. The ease of use and simple extensibility fostered more and more algorithmic developments. Thanks to the continuous interest of developers (especially M.Sc. and Ph.D. students who choose PetriDotNet as the framework of the...

Stochastic aspects of complex systems require more and more involved analysis approaches. Answering reachability and related analysis questions can often be reduced to steady-state, transient, reward or sensitivity value analysis of stochastic models. In this paper we introduce a configurable stochastic analysis framework which supports the user to...