An Approach to Building Decision Support Systems Based on an Ontology Service

Modern decision support systems (DSSs) need components for storing knowledge. Moreover, DSSs must support fuzzy inference to work with uncertainty. Ontologies are designed to represent knowledge of complex structures and to perform inference tasks. Developers must use the OWLAPI and SWRL API libraries to use ontology features. They are impossible to use in DSSs written in programming languages not for Java Virtual Machines. The FuzzyOWL library and the FuzzyDL inference engine are required to work with fuzzy ontologies. The FuzzyOWL library is currently unmaintained and does not have a public Git repository. Thus, it is necessary to develop the ontology service. The ontology service must allow working with ontologies and making fuzzy inferences. The article presents ontology models for decision support, fuzzy inference, and the fuzzy inference algorithm. The article considers examples of DSSs for balancing production capacities and image analysis. The article also describes the architecture of the ontology service. The proposed novel ontology models for decision support make it possible to reduce the time of a knowledge base formation. The ontology service can integrate with external systems with HTTP protocol.

Better state pictures facilitating state machine characteristic conjecture

The mutual exclusion protocol invented by Mellor-Crummey and Scott (called MCS protocol) is used to exemplify that state picture designs based on which the state machine graphical animation (SMGA) tool produces graphical animations should be better visualized. Variants of MCS protocol have been used in Java virtual machines and therefore the 2006 Edsger W. Dijkstra Prize in Distributed Computing went to their paper on MCS protocol. The new state picture design of a state machine formalizing MCS protocol is assessed based on Gestalt principles, more specifically proximity principle and similarity principle. We report on a core part of a formal verification case study in which the new state picture design and the SMGA tool largely contributed to the successful completion of the formal proof that MCS protocol enjoys the mutual exclusion property. The lessons learned acquired through our experiments are summarized as two groups of tips. The first group is some new tips on how to make state picture designs. The second one is some tips on how to conjecture state machine characteristics by using the SMGA tool. We also report on one more case study in which the state picture design has been made for the mutual exclusion protocol invented by Anderson (called Anderson protocol) and some characteristics of the protocol have been discovered based on the tips.

Managing the life cycle of Java Card applets in other Java virtual machines

Purpose – The purpose of this paper is to address the design, implementation, performance and limitations of an environment that emulates a secure element for rapid prototyping and debugging. Today, it is difficult for developers to get access to a near field communication (NFC)-secure element in current smartphones. Moreover, the security constraints of smartcards make in-circuit emulation and debugging of applications impractical. Therefore, an environment that emulates a secure element brings significant advantages for developers. Design/methodology/approach – The authors' approach to such an environment is the emulation of Java Card applets on top of non-Java Card virtual machines (e.g. Android Dalvik VM), as this would facilitate the use of existing debugging tools. As the operation principle of the Java Card VM is based on persistent memory technology, the VM and applications running on top of it have a significantly different life cycle compared to other Java VMs. The authors evaluate these differences and their impact on Java VM-based Java Card emulation. They compare possible strategies to overcome the problems caused by these differences, propose a possible solution and create a prototypical implementation to verify the practical feasibility of such an emulation environment. Findings – While the authors found that the Java Card inbuilt persistent memory management is not available on other Java VMs, they present a strategy to model this persistence mechanism on other VMs to build a complete Java Card run-time environment on top of a non-Java Card VM. Their analysis of the performance degradation in a prototypical implementation caused by additional effort put into maintaining persistent application state revealed that the implementation of such an emulation environment is practically feasible. Originality/value – This paper addresses the problem of emulating a complete Java Card run-time environment on top of non-Java Card virtual machines which could open and significantly ease the development of NFC secure element applications.