Célia Martinie

Task-model based assessment of automation levels: Application to space ground segments

Designing systems in such a way that as much functions as possible are automated has been the driving direction of research and engineering in aviation, space and more generally in computer science for many years. In the 90s many studies (e.g. [12] related to the notion of mode confusion) have demonstrated that fully automated systems are out of the grasp of current technologies and that additionally migrating functions [2] from the operator to the system might have disastrous impact on operations both in terms of safety and usability. In order to be able to design automation with a hedonic view of the involved factors (safety, usability, reliability, …) a complete understanding of operators tasks is required prior to considering migrating them to the system side. This paper proposes a contribution for reasoning about automation designs using a model-based approach exploiting refined task models. These models describe operations with enough details in order to reason about automation and to rationalize automation designs. In this paper we present how such representations can support the assessment of alternative design options for automation. The proposed approach is applied to satellite ground segments.

A model-based approach for supporting engineering usability evaluation of interaction techniques

This paper offers a contribution for engineering interaction techniques by proposing a model-based approach for supporting usability evaluation. This approach combines different techniques including formal analysis of models, simulation and, in particular, analysis of log data in a model-based environment. This approach is integrated in a process and is supported by a model-based CASE tool for modeling, simulation and evaluation of interactive systems. A case study illustrates the approach and operation of the tool. The results demonstrate that the log data at model level can be used not only to identify usability problems but also to identify where to operate changes to these models in order to fix usability problems. Finally we show how the analysis of log data allows the designer to easily shape up the interaction technique (as the results of log analysis are presented at the same abstraction level of models). Such as an approach offers an alternative to user testing that are very difficult to configure and to interpret especially when advanced interaction techniques are concerned

A multi-formalism approach for model-based dynamic distribution of user interfaces of critical interactive systems

Evolution in the context of use requires evolutions in the user interfaces even when they are currently used by operators. User Centered Development promotes reactive answers to this kind of evolutions either by software evolutions through iterative development approaches or at runtime by providing additional information to the operators such as contextual help for instance. This paper proposes a model-based approach to support proactive management of context of use evolutions. By proactive management we mean mechanisms in place to plan and implement evolutions and adaptations of the entire user interface (including behaviour) in a generic way. The approach proposed handles both concentration and distribution of user interfaces requiring both fusion of information into a single UI or fission of information into several ones. This generic model-based approach is exemplified on a safety critical system from space domain. It presents how the new user interfaces can be generated at runtime to provide a new user interface gathering in a single place all the information required to perform the task. These user interfaces have to be generated at runtime as new procedures (i.e. sequences of operations to be executed in a semi-autonomous way) can be defined by operators at any time in order to react to adverse events and to keep the space system in operation. Such contextual, activity-related user interfaces complement the original user interfaces designed for operating the command and control system. The resulting user interface thus corresponds to a distribution of user interfaces in a focus+context way improving usability by increasing both efficiency and effectiveness.

Enhanced Task Modelling for Systematic Identification and Explicit Representation of Human Errors

Task models produced from task analysis, are a very important element of UCD approaches as they provide support for describing users goals and users activities, allowing human factors specialists to ensure and assess the effectiveness of interactive applications. As user errors are not part of a user goal they are usually omitted from tasks descriptions. However, in the field of Human Reliability Assessment, task descriptions (including task models) are central artefacts for the analysis of human errors. Several methods (such as HET, CREAM and HERT) require task models in order to systematically analyze all the potential errors and deviations that may occur. However, during this systematic analysis, potential human errors are gathered and recorded separately and not connected to the task models. Such non integration brings issues such as completeness (i.e. ensuring that all the potential human errors have been identified) or combined errors identification (i.e. identifying deviations resulting from a combination of errors). We argue that representing human errors explicitly and systematically within task models contributes to the design and evaluation of error-tolerant interactive system. However, as demonstrated in the paper, existing task modeling notations, even those used in the methods mentioned above, do not have a sufficient expressive power to allow systematic and precise description of potential human errors. Based on the analysis of existing human error classifications, we propose several extensions to existing task modelling techniques to represent explicitly all the types of human error and to support their systematic task-based identification. These extensions are integrated within the tool-supported notation called HAMSTERS and are illustrated on a case study from the avionics domain.

A development process for usable large scale interactive critical systems: application to satellite ground segments

While a significant effort is being undertaken by the Human-Computer Interaction community in order to extend current knowledge about how users interact with computing devices and how to design and evaluate new interaction techniques, very little has been done to improve the reliability of software offering such interaction techniques. However, malfunctions and failures occur in interactive systems leading to incidents or accidents that, in aviation for instance, are [22] 80% of the time attributed to human error demonstrating the inadequacy between the system and its operators. As an error may have a huge impact on human life, strong requirements are usually set both on the final system and on the development process itself. Interactive safety-critical systems have to be designed taking into account on an equal basis several properties including usability, reliability and operability while their associated design process is required to handle issues such as scalability, verification, testing and traceability. However, software development solutions in the area of critical systems are not adequate leading to defects especially when the interactive aspects are considered. Additionally, the training program development is always designed independently from the system development leading to operators trained with inadequate material. In this paper we propose a new iterative design process embedding multiple design and modeling techniques (both formal and informal) advocated by HCI and dependable computing domains. These techniques have been adapted and tuned for interactive systems and are used in a synergistic way in order to support the integration of factors such as usability, dependability and operability and at the same time in order to deal with scalability, verification and traceability.

Analysis of WIMP and Post WIMP Interactive Systems based on Formal Specification

While designing interactive software, the use of a formal specification technique is of great help by providing non-ambiguous, complete and concise descriptions. The advantages of using such a formalism is widened if it is provided by formal analysis techniques that allow to prove properties about the design, thus giving an early verification to the designer before the application is actually implemented. This paper presents how models built using the Interactive Cooperative Objects formalism (ICOs) are amenable to formal verification. The emphasis is on the behavioral part of the description of the interactive systems and more precisely on the properties at the interaction technique level. However, the process and the associated tools can be generalized to the other parts of the interactive systems (including the non-interactive parts).

Systematic automation of scenario-based testing of user interfaces

Ensuring the effectiveness factor of usability consists in ensuring that the application allows users to reach their goals and perform their tasks. One of the few means for reaching this goal relies on task analysis and proving the compatibility between the interactive application and its task models. Synergistic execution enables the validation of a system against its task model by co-executing the system and the task model and comparing the behavior of the system against what is prescribed in the model. This allows a tester to explore scenarios in order to detect deviations between the two behaviors. Manual exploration of scenarios does not guarantee a good coverage of the analysis. To address this, we resort to model-based testing (MBT) techniques to automatically generate scenarios for automated synergistic execution. To achieve this, we generate, from the task model, scenarios to be co-executed over the task model and the system. During this generation step we explore the possibility of including considerations about user error in the analysis. The automation of the execution of the scenarios closes the process. We illustrate the approach with an example.

A design process for exhibiting design choices and trade-offs in (potentially) conflicting user interface guidelines

In the last decades a huge amount of knowledge about user interface design has been gathered in the form of guidelines. Quite often, guidelines are compiled according to user interface properties (e.g. usability, accessibility) and/or application domains (e.g. Web, mobile). In many situations designers have to combine several guideline sets in order to address the specific application domain and the desired set of properties corresponding to the application under consideration. Despite the fact that the problems related to the selection of guidelines from different sources are not new, the occurrence and management of conflicting guidelines are poorly documented leaving designers with little help in order to handle conflicts in a rationale and consistent way. In this paper we revise the questions related to selection and management of conflicting guidelines and we propose a systematic approach based on design rationale tools and techniques for exhibiting choices and trade-offs when combining different guidelines sets. This paper illustrates how such as an approach can also be used to deepen the knowledge on the use of user interface guidelines recording decisions across projects in an iterative way.

Transparent Automation for Assessing and Designing better Interactions between Operators and Partly-Autonomous Interactive Systems

Human Automation Interaction deals with finding the best balance for the allocation of tasks and functions between operators and the systems being operated. Automation is typically addressed at a very high level i.e. at the procedures or tasks that have to be performed to reach a goal. When these automations are not adequately designed (or correctly understood by the operator), they may result in so called automation surprises [30], [36] that degrade, instead of enhance, the overall performance of the operations. However, such previous work on automation surprises have overlooked the importance of automation in order for the operator to trigger these tasks and the fact that an interactive command and control system has to be used. This interactive system usually integrates low level automation that might also result in automation surprises. The paper proposes a stepwise approach for identifying, describing and analyzing the automation level of interaction techniques in an explicit way. This approach provides support for analyzing potential automation surprises that can arise from the interaction technique but also for identifying how to modify them in order to reduce performance degradations due to automation surprises at the interaction level. Based on a classification of interaction techniques we demonstrate that a model-based approach can support the design and assessment of the automation that interaction techniques feature and that is usually hidden from the users.

Bridging the gap between a behavioural formal description technique and a user interface description language: Enhancing ICO with a graphical user interface markup language

In the last years, User Interface Description Languages (UIDLs) appeared as a suitable solution for developing interactive systems. In order to implement reliable and efficient applications, we propose to employ a formal description technique called ICO (Interactive Cooperative Object) that has been developed to cope with complex behaviours of interactive systems including event-based and multimodal interactions. So far, ICO is able to describe most of the parts of an interactive system, from functional core concerns to fine grain interaction techniques, but, even if it addresses parts of the rendering, it still not has means to describe the effective rendering of such interactive system. This paper presents a solution to overcome this gap using markup languages. A first technique is based on the Java technology called JavaFX and a second technique is based on the emergent UsiXML language for describing user interface components for multi-target platforms. The proposed approach offers a bridge between markup language based descriptions of the user interface components and a robust technique for describing behaviour using ICO modelling. Furthermore, this paper highlights how it is possible to take advantage from both behavioural and markup language description techniques to propose a new model-based approach for prototyping interactive systems. The proposed approach is fully illustrated by a case study using an interactive application embedded into interactive aircraft cockpits.