µ-Charts and Z: Examples and extensions

μ-Charts are a way of specifying reactive systems, i.e. systems which are in some environment to which they have to react, based on the well-established formalism Statecharts. This paper gives (very abbreviated) examples of translating μ-charts to Z, which is itself a well-established language for specifying computational systems with tried and tested methods and support tools which guide its effective use in systems development. We undertake this translation in order that investigation of the modelled system can be performed before expensive and lengthy implementation is considered. We also present an extension of the μ-charts and the related Z to deal with a simple command language, local variables and integer-valued signals

Interactive situation models for systems development

Devising principles for systems representation and analysis that can cope with the complexity of the interactions between programmable components and human agents in modern computing applications is a challenging and fundamental problem. Understanding the role of human and inanimate components within a reactive system, for instance, involves not only input-output transformations, but also communication and stimulus-response issues. This paper proposes novel computer-based interactive situation models to assist systems development. Such models provide an environment within which the human interpreter can explore the relationships between observables and the patterns of behaviour associated with a system component with particular reference to its external real-world semantics. They are constructed using principles based upon observation, agency and dependency ("Empirical Modelling") that have been developed at the University of Warwick. This paper describes and illustrates ! the characteristics of interactive situation models in detail, and concludes with a brief discussion of their potential significance for systems development

Conformance Checking for Pushdown Reactive Systems based on Visibly Pushdown Languages

Testing pushdown reactive systems is deemed important to guarantee a precise and robust software development process. Usually, such systems can be specified by the formalism of Input/Output Visibly Pushdown Labeled Transition System (IOVPTS), where the interaction with the environment is regulated by a pushdown memory. Hence a conformance checking can be applied in a testing process to verify whether an implementation is in compliance to a specification using an appropriate conformance relation. In this work we establish a novelty conformance relation based on Visibly Pushdown Languages (VPLs) that can model sets of desirable and undesirable behaviors of systems. Further, we show that test suites with a complete fault coverage can be generated using this conformance relation for pushdown reactive systems.Comment: arXiv admin note: substantial text overlap with arXiv:2107.1142

Bigraph Metaprogramming for Distributed Computation

Ubiquitous computing is a paradigm that emphasises integration of computing activities into the fabric of everyday life. With the increasing availability of small, cheap computing devices, the ubiquitous computing model seems more and more likely to supplant desktop computing as the dominant paradigm. Similarly, the presence of high-speed network connectivity between vast numbers of computers has already made distributed computing the preferred paradigm for many application domains. Unfortunately, traditional approaches to software development are not necessarily well-suited to developing software in a post-desktop world. We present an extension to the bigraphical reactive systems formalism that enables us to construct a programming language based upon it. We believe that this programming language provides programmers with an environment better suited to the challenges that arise when creating software within a distributed or ubiquitous computing paradigm. We detail our modification to the theory of bigraphical reactive systems that enables metaprogramming. Finally, we provide a description of our prototype implementation of a programming language that enables metaprogramming of bigraphical reactive systems

Agent-based simulation of animal behaviour

In this paper it is shown how animal behaviour can be simulated in an agent-based manner. Different models are shown for different types of behaviour, varying from purely reactive behaviour to pro-active, social and adaptive behaviour. The compositional development method for multi-agent systems DESIRE and its software environment supports the conceptual and detailed design, and execution of these models. Experiments reported in the literature on animal behaviour have been simulated for a number of agent models

Transformer‐Based Z‐Source Inverter with MVDC Link

Z‐source inverters have attracted considerable attention in renewable energy systems like photovoltaic (PV) systems due to advantages such as buck–boost power conversion in single stage, shoot-through capability, and wide range of input voltage regulation. Transformer-Based Z-source inverters (TransZSI) based on magnetically coupled inductors and reduced number of passive components can be used to improve the boost capacity of these inverters, and to increase the voltage levels. Medium voltage DC (MVDC) is being used more and more in distribution grids and renewable energy systems. This paper presents a transZ-source inverter with MVDC link where renewable energy systems and energy storage systems can be integrated. The active and reactive powers and DC voltage are controlled by acting on the modulation index and shoot-through duty cycle of the converter. The trans-Z-source inverter is evaluated under different operating conditions to illustrate its suitable operation. © 2022, European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ). All rights reserved

Confirmation of co-denitrification in grazed grassland

peer-reviewedPasture-based livestock systems are often associated with losses of reactive forms of nitrogen (N) to the environment. Research has focused on losses to air and water due to the health, economic and environmental impacts of reactive N. Di-nitrogen (N2) emissions are still poorly characterized, both in terms of the processes involved and their magnitude, due to financial and methodological constraints. Relatively few studies have focused on quantifying N2 losses in vivo and fewer still have examined the relative contribution of the different N2 emission processes, particularly in grazed pastures. We used a combination of a high 15N isotopic enrichment of applied N with a high precision of determination of 15N isotopic enrichment by isotope-ratio mass spectrometry to measure N2 emissions in the field. We report that 55.8 g N m−2 (95%, CI 38 to 77 g m−2) was emitted as N2 by the process of co-denitrification in pastoral soils over 123 days following urine deposition (100 g N m−2), compared to only 1.1 g N m−2 (0.4 to 2.8 g m−2) from denitrification. This study provides strong evidence for co-denitrification as a major N2 production pathway, which has significant implications for understanding the N budgets of pastoral ecosystems.The authors are grateful for the funding that was provided through the Research Stimulus Fund Program administered by the Department of Agriculture & Food under the National Development Plan 2007–2013 RSF 07536. The first author is grateful for the funding provided by Teagasc through the Walsh Fellowship Scheme

Conceptual modeling for the design of intelligent and emergent information systems

A key requirement to today's fast changing economic environment is the ability of organizations to adapt dynamically in an effective and efficient manner. Information and Communication Technologies play a crucially important role in addressing such adaptation requirements. The notion of `intelligent software' has emerged as a means by which enterprises can respond to changes in a reactive manner but also to explore, in a pro-active manner, possibilities for new business models. The development of such software systems demands analysis, design and implementation paradigms that recognize the need for ‘co-development’ of these systems with enterprise goals, processes and capabilities. The work presented in this paper is motivated by this need and to this end it proposes a paradigm that recognizes co-development as a knowledge-based activity. The proposed solution is based on a multi-perspective modeling approach that involves (i) modeling key aspects of the enterprise, (ii) reasoning about design choices and (iii) supporting strategic decision-making through simulations. The utility of the approach is demonstrated though a case study in the field of marketing for a start-up company

A formal verification assistant for TROMLAB environment

Formal specifications have become a strong basis in the field of safety critical systems development. Safety, liveness and time bounded properties are characteristics of such systems where the need to secure their adequate implementation is very high. Formal verification of such properties is the research field of this thesis. It presents an automated tool that enables mechanized axiom extraction from real-time reactive systems. It is implemented within TROMLAB which is a development environment based on the Timed Reactive Object Model (TROM). The objective of this tool is to be used within the verification methodology of TROM as an automated assistant to facilitate time dependent property proving for model developers