Anca Goron

Assuring safety in air traffic control systems with argumentation and model checking

We present a framework to model a recommender system for an air traffic control.We combine argumentation and model checking for doing model update in Hybrid Logics.We apply our approach to model repair in an unmanned aerial vehicle.We extend Defeasible Logic Programming to perform continuous reasoning. Although the continuous safety technology advances in fields like air traffic control (ATC) systems or medical devices, the crux of safety assurance still comes down to human decision makers, which, within the context of having to define priorities while simultaneously considering different contextual criteria, present a constant high risk of erroneous decisions. We illustrate in this article a recommender framework for assisting flight controllers, which combines argumentation theory and model checking in the evaluation of trade-offs and compromises to be made in the presence of incomplete and potentially inconsistent information. We view a Hybrid Kripke model as a description of an ATC domain and we apply a rational decision strategy based on Hybrid Logics and Defeasible Reasoning to assist the process of model update when the system has to accommodate new properties or norm constraints. When the model fails to verify a property, a defeasible logic program is used to analyze the current state and perform updating operations on the model. The introduced decision making framework is tested on a recommender system in ATC and model update is demonstrated with respect to the verification and adaption of unmanned aerial vehicles routes in the air traffic space. The results show an important potential for the presented framework to be integrated directly into existing decision-making routines for achieving higher accuracy in recommender system methods.

Model checking as support for inspecting compliance to rules in flexible processes

Context: In backing business processes with information technology, a difficult trade-off appears between the desire to control processes for avoiding undesirable executions, and the flexibility that users need in order to attain their higher level goals. While this is a general trend in general business processes, it is even more acute in specific domains like the medical area, where the clinical guidelines are expected to contribute to the optimization of medical assistance.Objective: We study model checking as support for understanding and solving the inconsistencies between the process models and their corresponding execution. The aim is to provide various human users with output in controlled English for the checking of properties about the execution of such processes, and perhaps input in controlled English for properties of interest from the point of view of the user.Method: For the conformance checking of such complex situations, we use an extended version of a Hybrid Logics model checking tool, for the verification of various properties within an abstract representation model. The extension with Description Logics helps to exploit a more refined representation of the entities involved in the execution of processes. The advantages of using the model checker in visualizing and verbalizing connections of the properties checked with their dependencies over time are shown on a sore throat running scenario, relative to its corresponding clinical guidelines.Results: With new data for an alternative run of the execution, our method can update the abstract model to enable the user to see what might happen or might have happened in such runs of the process model. The new updated abstract model corresponding to the new real situations is then used to analyze whether the overall state is acceptable or should further actions be considered to arrive at an acceptable state of the world.Conclusion: Our results show how the combination of Hybrid Logic and Description Logic can provide the necessary abstraction for the checking to be carried out at a level understandable by the human user when the properties of interest can be translated by a controlled English language interface. HighlightsConformance checking of flexible processes with verbalization for human users.Properties verified can be expressed straightforwardly in controlled English.Update of abstract model to new real world situations.Hybrid Logic, to describe dynamics, and Description Logics, for concepts.Abstractions used by human users are shown in significant decisions.

A formal approach for identifying assurance deficits in unmanned aerial vehicle software

.While formal methods have proved to be unfeasible for large scale systems, argument-based safety cases offer a plausible alternative basis for certification of critical software. Our proposed method for increasing safety combines formal methods with argumentation-based reasoning. In a first step, we provide a formal representation of the the argumentative-based Goal Structuring Notation (GSN) standard used in industry. In a second step, our solution exploits reasoning in description logic to identify assurance deficits in the GSN model. The identified flaws are given to a hybrid logic-based model checker to be validated against a Kripke model. The method is illustrated for an unmanned aerial vehicle software, with reasoning performed in RacerPro engine and the HLMC model checker based on hybrid logic.

Embedding value-based argumentation in persuasive dialogs

With the aim of highlighting the strategic considerations for argumentation in persuasion we use hybrid logic to describe the behavior of agents in concrete situations aiming to provide a more expressive view of the complex events. Although using value-based argumentation, by exploiting the extra-dialogical goals of the arguer we concentrate on the meta-level of the moves in the dialog.

Towards justifying norm compliance

We introduce justifications in normative systems with the aim to better understand the compliance to norms, including situations of conflict between norms that might arise. To stay at the level of explanations on justification we employ the Hybrid Justification Logic. We show the grounding of the abstract norms to the concrete ones within an example for a traffic management system. The interplay between norms is judged at the values of the society through Value-Based Argumentation. The justification for the way agents comply or not to the norms, relative to their social values, has been implemented in the CaSAPI argumentation environment.

HLMC: a Hybrid Logic Tool for Model Checking in Verification of Administrative Processes

Nowadays, public services can be modeled, analyzed and implemented using notations and tools for the business process (BP) abstraction. Applying such an approach allows public administrations (PAs) to better react to the undergoing transformation in service provisioning, improving service quality in order to satisfy citizens and business requests while coping with decreasing budgets. This paper introduces a novel approach to verifying administrative processes based on HLMC, a hybrid logic model checker

Verifying Compliance for Business Process Logs with a Hybrid Logic Model Checker

Given that organizations rely on the support of information systems in automating their business processes, the auditing of these processes is a complex task because it needs to consider both the business process model and the relevant data logs. For the compliance checking of such business situations, we present an extended version of a Hybrid Logics model checking tool, with temporal operators. The support for temporal operators allows for tracing the event logs and the verification of properties, within an abstract representation model corresponding to the intended concern of auditing.

A temporal view on Model Checking Hybrid Logics

We tackle the problem of Hybrid Logics Model Checking and its current limitations on what it concerns the available instrumentation support. In this direction, we present an extended version of an available Hybrid Logics model checking tool, which supports the use of both specific Hybrid Logics and also temporal operators for verifying system properties. By adding support for temporal operators, the extended version will make easier the model verification problem by taking the advantages of both worlds in one place.

Checking the norms for explanation

If the purpose of agent organizations is to create power relationships, not just constraining agents, but to enable them to face the dynamics of the environment, the effect of norms and their interplay is a significant practical aspect. To better understand how agents can face dynamism and improve the overall social gain, we present our current view on the model checking of properties for the behavior of a normative system. We consider goal oriented processes as a flexible description of the environment within which the normative organization has to perform as well as possible. To actively involve the users and domain experts in the modeling of processes, we show the verbalizing step that leads to controlled natural language.

Using arguments on requirements for services

When dealing with public descriptions of interacting software services, we focus towards identifying those specification gaps from the description of the service workflows based on Open Workflow Nets. Apart from the functional requirements we are tackling the use of estimated non-functional requirements by arguments. We are using the reasoning power of the Value based Argumentation Framework, which allows us to decide upon the best course of action to consider for successfully accomplishing the pre-established functional requirements of the interacting software services, and also to solve the preferences in an efficient and time consuming manner.