topauthor: Gray_P* : Human-Computer Interaction Bibliography Search

[1] INTERNET GIST: Glasgow Interactive Systems Group 2010-04-20 United Kingdom, Scotland, Glasgow University of Glasgow

www.dcs.gla.ac.uk/gist/

Multimodal Interaction Group
	+ Brewster, Stephen
Social Ubiquitous Mobile Group
	+ Chalmers, Matthew
Interactive Teaching and Technology
	+ Cutts, Quintin
Technology for Learning and Teaching
	+ Draper, Steve
Software, Technology, Tools and Methods
	+ Gray, Phil
Glasgow Accident Analysis Group
	+ Johnson, Chris
Dynamics and Interaction
	+ Murray-Smith, Rod
Diagram Evaluation
	+ Purchase, Helen
Graphical Authentification and Email Usage
	+ Renaud, Karen

Summary: GIST is an inter-disciplinary Human-Computer Interaction (HCI) research group based at the University of Glasgow investigating all aspects of interactive systems focusing on ubiquitous computing, multimodal interaction, visualisation and modelling.
Key areas:

Mobile, wireless and ubiquitous computing
Interactive system architectures
Multimodal interaction (haptics, earcons and 3D sound)
Interfaces for blind, visually impaired people and older people
Home care systems
Collaborative filtering visualisation and information retrieval
Accident analysis and safety critical systems
User modelling and pattern recognition
Theories of information representation
Web authentification, Dynahand, email stress
Electronic Voting Systems, Schools Computing

[2] EDITED BOOK The Engineering of Mixed Reality Systems Human-Computer Interaction Series / Dubois, Emmanuel / Gray, Philip / Nigay, Laurence 2010 n.21 p.445 Springer London

DOI: 10.1007/978-1-84882-733-2

ISBN: 978-1-84882-732-5 (print), 978-1-84882-733-2 (online)

Link to Digital Content at Springer

Introduction (1-6)
	+ Dubois, Emmanuel
	+ Gray, Phil
	+ Nigay, Laurence
== Interaction Design ==
An Integrating Framework for Mixed Systems (9-31)
	+ Coutrix, Céline
	+ Nigay, Laurence
A Holistic Approach to Design and Evaluation of Mixed Reality Systems (33-55)
	+ Nilsson, Susanna
	+ Johansson, Björn
	+ Jönsson, Arne
Embedded Mixed Reality Environments (57-78)
	+ Schnädelbach, Holger
	+ Galani, Areti
	+ Flintham, Martin
The Semantic Environment: Heuristics for a Cross-Context Human-Information Interaction Model (79-99)
	+ Resmini, Andrea
	+ Rosati, Luca
Tangible Interaction in Mixed Reality Systems (101-120)
	+ Couture, Nadine
	+ Rivière, Guillaume
	+ Reuter, Patrick
Designing a Mixed Reality Intergenerational Entertainment System (121-141)
	+ Khoo, Eng Tat
	+ Merritt, Tim
	+ Cheok, Adrian David
Auditory-Induced Presence in Mixed Reality Environments and Related Technology (143-163)
	+ Larsson, Pontus
	+ Väljamäe, Aleksander
	+ Västfjäll, Daniel
	+ Tajadura-Jiménez, Ana
	+ Kleiner, Mendel
An Exploration of Exertion in Mixed Reality Systems via the "Table Tennis for Three" Game (165-182)
	+ Mueller, Florian 'Floyd'
	+ Gibbs, Martin R.
	+ Vetere, Frank
Developing Mixed Interactive Systems: A Model-Based Process for Generating and Managing Design Solutions (183-208)
	+ Gauffre, Guillaume
	+ Charfi, Syrine
	+ Bortolaso, Christophe
	+ Bach, Cédric
	+ Dubois, Emmanuel
== Software Design and Implementation ==
Designing Outdoor Mixed Reality Hardware Systems (211-231)
	+ Avery, Benjamin
	+ Smith, Ross T.
	+ Piekarski, Wayne
	+ Thomas, Bruce H.
Multimodal Excitatory Interfaces with Automatic Content Classification (233-250)
	+ Williamson, John
	+ Murray-Smith, Roderick
Management of Tracking for Mixed and Augmented Reality Systems (251-273)
	+ Keitler, Peter
	+ Pustka, Daniel
	+ Huber, Manuel
	+ Echtler, Florian
	+ Klinker, Gudrun
Authoring Immersive Mixed Reality Experiences (275-291)
	+ Misker, Jan M. V.
	+ van der Ster, Jelle
Fiia: A Model-Based Approach to Engineering Collaborative Augmented Reality (293-312)
	+ Wolfe, Christopher
	+ Smith, J. David
	+ Phillips, W. Greg
	+ Graham, T. C. Nicholas
A Software Engineering Method for the Design of Mixed Reality Systems (313-334)
	+ Dupuy-Chessa, S.
	+ Godet-Bar, G.
	+ Pérez-Medina, J.-L.
	+ Rieu, D.
	+ Juras, D.
== Applications of Mixed Reality ==
Enhancing Health-Care Services with Mixed Reality Systems (337-356)
	+ Stantchev, Vladimir
The eXperience Induction Machine: A New Paradigm for Mixed-Reality Interaction Design and Psychological Experimentation (357-379)
	+ Bernardet, Ulysses
	+ Badia, Sergi Bermúdez i
	+ Duff, Armin
	+ Inderbitzin, Martin
	+ Groux, Sylvain Le
	+ Manzolli, Jônatas
	+ Mathews, Zenon
	+ Mura, Anna
	+ Väljamäe, Aleksander
	+ Verschure, Paul F. M. J
MyCoach: In Situ User Evaluation of a Virtual and Physical Coach for Running (381-397)
	+ Biemans, Margit
	+ Haaker, Timber
	+ Szwajcer, Ellen
The RoboCup Mixed Reality League -- A Case Study (399-418)
	+ Gerndt, Reinhard
	+ Bohnen, Matthias
	+ Guerra, Rodrigo da Silva
	+ Asada, Minoru
== Applications of Mixed Reality ==
Mixed-Reality Prototypes to Support Early Creative Design (419-445)
	+ Safin, Stéphane
	+ Delfosse, Vincent
	+ Leclercq, Pierre

[3] Ethics, Roles and Relationships in Interaction Design in Developing Regions Workshops / Roibás, Anxo Cereijo / Dearden, Andy / Dray, Susan M. / Gray, Phil / Thomas, John C. / Winters, Niall Proceedings of IFIP INTERACT'09: Human-Computer Interaction 2009-08-24 v.2 p.963-964

Keywords: International development; ethics; capacity-building; cross-cultural design

Link to Digital Content at Springer

Summary: A workshop to explore ethical and organisational issues associated with interaction design efforts conducted in developing regions of the world. The workshop will discuss the challenges of conducting this type of work in a way that can bring sustainable benefits to people living in developing regions.

[4] User evaluation of OIDE: a rapid prototyping platform for multimodal interaction Improving interaction engineering / McGee-Lennon, Marilyn Rose / Ramsay, Andrew / McGookin, David / Gray, Philip ACM SIGCHI 2009 Symposium on Engineering Interactive Computing Systems 2009-07-15 p.237-242

Keywords: interaction design, multimodal interaction, open interface, rapid prototyping, user evaluations

ACM Digital Library Link

Summary: The Open Interface Development Environment (OIDE) was developed as part of the OpenInterface (OI) platform, an open source framework for the rapid development of multimodal interactive systems. It allows the graphical manipulation of components stored in a structured and rich repository of modalities and interaction techniques. The platform is expected to act as a central tool for an iterative user centred design process for multimodal interactive system design. This paper presents a user study (N=16) designed to explore how the platform was used in practice by multimodal interaction designers and developers.
Participants were introduced to the features and functionality of the tool via tutorials and then engaged in an open multimodal design exercise. Participants were expected to explore various multimodal solutions to the design scenario using both traditional prototyping tools and the features available to them via the OIDE prototyping tool.
The workshops were recorded and the interaction and dialogue examined to gather feedback on how the OI tool was used or could be used to support or enhance the design stages of prototyping a multimodal application or interface. The results indicate that the OI platform could be a useful tool to support the early design stages during multimodal interaction design. The tool appeared to promote thinking about and using different modalities. The teams varied in size and composition and this appears to have an effect on how the teams approached the task and exploited the OI prototyping tool. We will offer some guidelines as to how open, rapid prototyping tools such as OIDE can be improved to better support multimodal interaction design.

[5] Affective feedback: an investigation into the role of emotions in the information seeking process Non-topicality / Arapakis, Ioannis / Jose, Joemon M. / Gray, Philip D. Proceedings of the 31st Annual International ACM SIGIR Conference on Research and Development in Information Retrieval 2008-07-20 p.395-402

ACM Digital Library Link

Summary: User feedback is considered to be a critical element in the information seeking process, especially in relation to relevance assessment. Current feedback techniques determine content relevance with respect to the cognitive and situational levels of interaction that occurs between the user and the retrieval system. However, apart from real-life problems and information objects, users interact with intentions, motivations and feelings, which can be seen as critical aspects of cognition and decision-making. The study presented in this paper serves as a starting point to the exploration of the role of emotions in the information seeking process. Results show that the latter not only interweave with different physiological, psychological and cognitive processes, but also form distinctive patterns, according to specific task, and according to specific user.

[6] An integrated approach to supporting interaction evolution in home care systems Homecare systems / McBryan, Tony / McGee-Lennon, Marilyn R. / Gray, Phil Proceedings of the 1st International Conference on PErvasive Technologies Related to Assistive Environments 2008-07-16 p.45

Keywords: ageing population, context-aware, dynamic system, evaluation criteria, evolution, home care system, interaction, requirements engineering, user preferences

ACM Digital Library Link

Summary: There are many sources of change within the domain of home care. People have changing needs, beliefs, and preferences regarding their care plan and how they might want to interact with existing and emerging home care technologies. The devices and services available to the user are likely to change over time depending on a person's capabilities or location within the home and the current devices and services available. The resulting interaction methods can therefore also change in accordance with the room location, available devices or displays, or preferred modalities. Home care systems therefore need to offer configuration possibilities that support this change. Computer systems offer methods and tools to support configuration in the short term, but do not provide mechanisms for supporting configuration over both short and long term. This paper presents an approach that addresses this issue in the home care domain by integrating methods for interaction requirements engineering with system support for turning those requirements into a working configuration. Both the methods and system support are designed to address a gradual process of change -- 'interaction evolution' in home care. We present the key features of our approach using a home care scenario and consider our progress to date in implementing and validating the approach.

[7] A Design-Oriented Information-Flow Refinement of the ASUR Interaction Model / Dubois, Emmanuel / Gray, Philip 2007 Engineering for Human-Computer Interaction 2007-03-22 p.465-482

Keywords: Mixed Interactive Systems; User's Interaction Modelling; Requirements Capture; Information flow characterisation; Design Analysis; Interaction Path

Link to Digital Content at Springer

Summary: The last few years have seen an explosion of interaction possibilities opened up by ubiquitous computing, mobile devices, and tangible interaction. Our methods of modelling interaction, however, have not kept up. As is to be expected with such a rich situation, there are many ways in which interaction might be modelled, focussing, for example, on user tasks, physical location(s) and mobility, data flows or software elements. In this paper, we present a model and modelling technique intended to capture key aspects of user's interaction of interest to interactive system designers, at the stage of requirements capture and early design. In particular, we characterise the interaction as a physically mediated information exchange, emphasizing the physical entities involved and their relationships with the user and with one another. We apply the model to two examples in order to illustrate its expressive power.

[8] Domino: Exploring Mobile Collaborative Software Adaptation / Bell, Marek / Hall, Malcolm / Chalmers, Matthew / Gray, Philip D. / Brown, Barry Proceedings of Pervasive 2006: International Conference on Pervasive Computing 2006-05-07 p.153-168

Link to Digital Content at Springer

Summary: Social Proximity Applications (SPAs) are a promising new area for ubicomp software that exploits the everyday changes in the proximity of mobile users. While a number of applications facilitate simple file sharing between co -- present users, this paper explores opportunities for recommending and sharing software between users. We describe an architecture that allows the recommendation of new system components from systems with similar histories of use. Software components and usage histories are exchanged between mobile users who are in proximity with each other. We apply this architecture in a mobile strategy game in which players adapt and upgrade their game using components from other players, progressing through the game through sharing tools and history. More broadly, we discuss the general application of this technique as well as the security and privacy challenges to such an approach.

[9] Agile development: opportunity or fad? Panels / Sharp, Helen / Biddle, Robert / Gray, Phil / Miller, Lynn / Patton, Jeff Proceedings of ACM CHI 2006 Conference on Human Factors in Computing Systems 2006-04-22 v.2 p.32-35

ACM Digital Library Link

Summary: The importance of integrating software engineering and HCI methods has been recognised for many years. Agile development is a new approach to software engineering that explicitly champions an active role for the customer. Indeed, eXtreme Programming (XP), one of the most popular agile development methods, strives to include a real user(s) in the team who is located 'on-site' with software developers.
In this panel we will debate whether or not agile software development provides an opportunity to integrate HCI and software engineering concerns. The panel members represent a wide cross-section of experiences in this area and will consider how agile development can help improve the current situation, consider specific example scenarios provided by the audience, and, with the audience's help, will decide whether agile development is an opportunity not to be missed, or just another fad that will pull the two communities further apart.

[10] The Effect of Age and Font Size on Reading Text on Handheld Computers Long Papers: Accessibility / Darroch, I. / Goodman, J. / Brewster, S. / Gray, P. Proceedings of IFIP INTERACT'05: Human-Computer Interaction 2005-09-12 p.253-266

Link to Digital Content at SpringerLink

Summary: Though there have been many studies of computer based text reading, only a few have considered the small screens of handheld computers. This paper presents an investigation into the effect of varying font size between 2 and 16 point on reading text on a handheld computer. By using both older and younger participants the possible effects of age were examined. Reading speed and accuracy were measured and subjective views of participants recorded. Objective results showed that there was little difference in reading performance above 6 point, but subjective comments from participants showed a preference for sizes in the middle range. We therefore suggest, for reading tasks, that designers of interfaces for mobile computers provide fonts in the range of 8-12 point to maximize readability for the widest range of users.

[11] How can we best use landmarks to support older people in navigation? / Goodman, J. / Brewster, S. A. / Gray, P. Behaviour and Information Technology 2005 v.24 n.1 p.3-20

Link to Article at journalsonline.tandf.co.uk

Summary: Although landmarks are an integral part of navigation, they have rarely been used explicitly within electronic pedestrian navigation aids. We describe a two-part study into the use of landmarks in such aids, using a set of field experiments. The first part investigated whether such devices can be effective for older adults (over 60 years old), who might particularly benefit from them due to declines in sensory, cognitive and motor abilities. The second part compared the effectiveness of different methods of presenting landmark information. We show that a pedestrian navigation aid based around landmarks is particularly useful for older people and demonstrate that text, speech and photographs are all effective ways of presenting landmark information, although speech on its own has some drawbacks. We found that different people prefer information to be presented in different modalities, indicating a need for personalisation, although multi-modality may also help to address this issue.

[12] Using Landmarks to Support Older People in Navigation Full Papers: User Differences and Navigation / Goodman, Joy / Gray, Phil / Khammampad, Kartik / Brewster, Stephen Proceedings of 2004 Conference on Human-Computer Interaction with Mobile Devices and Services 2004-09-13 p.38-48

Link to Digital Content at Springer

Summary: Although landmarks are an integral aspect of navigation, they have rarely been used within electronic navigation aids. This paper describes the design of a pedestrian navigation aid for a handheld computer, which guides the user along a route using photographs of landmarks, together with audio and text instructions that reference these landmarks. This aid was designed with older users in mind who often find their mobility hampered by declines in sensory, cognitive and motor abilities. It was tested against the standard paper map for the test area with both younger and older people and their performance and subjective workload were measured. The results show that such an aid can significantly outperform a paper-based map and that older people derive substantially more benefit from it than do younger people.

[13] Mobile Support for Team-Based Field Surveys Posters / Hall, Malcolm / Gray, Philip Proceedings of 2004 Conference on Human-Computer Interaction with Mobile Devices and Services 2004-09-13 p.431-435

Link to Digital Content at Springer

Summary: This paper describes a study of the use of multimedia networked location-aware mobile computers to support team-based survey-oriented fieldwork. Existing systems do not provide fully integrated support for collaborative data capture and review, or access to distributed real time information on survey progress and status, all of which are crucial for the conduct and management of surveys often carried out under inflexible time constraints. We developed a mobile system to address these shortcomings and performed an evaluation in an archaeological field survey, supporting over two-hundred data collection incidents over five days, and providing further insight into the field work data collection process.

[14] GUIDE-ME: graphical user interface for the design of mixed interactive environment based on the ASUR notation Conception (Design) / Viala, Joël / Dubois, Emmanuel / Gray, Philip D. Proceedings of the 2004 French-speaking conference on Mobility and ubiquity computing 2004-06-01 p.74-77

Keywords: augmented reality, augmented virtuality, design method, mixed systems, tool support for ASUR

ACM Digital Library Link

Summary: In this paper we present GUIDE-ME, Graphical User Interface for the DEsign of Mixed interactive Environment, a graphical tool to the design and the description of mixed systems also called ubiquitous systems. Based on the ASUR notation, that supports the description and the reasoning of mixed systems during the design phase, GUIDE-ME offers graphical editing capabilities for the manipulation of this notation. GUIDE-ME opens up new perspectives in terms of combinations of this notation with other HCI design methods and tools. To illustrate this, we present the links we established between GUIDE-ME and ASURSim, a platform supporting the simulation of the interaction of a mobile user in mixed 3D environment.

[15] Exploring the design and engineering of mixed reality systems Workshops / Dubois, Emmanuel / Gray, Philip / Trevisan, Daniela / Vanderdonckt, Jean Proceedings of the 2004 International Conference on Intelligent User Interfaces 2004-01-13 p.374-375

ACM Digital Library Link

Summary: This IUI'04 workshop is an opportunity to identify and articulate the key research challenges for the design and engineering of mixed reality systems. By clarifying and systematizing these challenges, we can improve our own understanding of the current state of the field, stimulate research activity, especially collaboration, and help establish the design of MR systems as a distinct research area.

[16] ASUR++: Supporting the design of mobile mixed systems / Dubois, Emmanuel / Gray, Philip / Nigay, Laurence Interacting with Computers 2003 v.15 n.4 p.497-520

Keywords: ASUR++ design notation; Design method; Mobile augmented reality systems; Ergonomic analysis

Summary: In this paper we present ASUR++, a notation for describing, and reasoning about the design of, mobile interactive computer systems that combine physical and digital objects and information: mobile mixed systems. ASUR++ helps a designer to specify the key characteristics of such systems and to focus on the relationship between physical objects and actions and digital information exchanges. Following a brief introduction to the notation, we illustrate its potential usefulness via examples based on the design of an augmented museum gallery. We conclude with a consideration of the integration of ASUR++ into the system development process and its augmentation via associated methods and tools.

[17] Architecture logicielle conceptuelle pour la capture de contexte / Nigay, Laurence / Gray, Phil Proceedings of the 2002 Conference of the Association Francophone d'Interaction Homme-Machine 2002-11-26 p.211-214

Languages: French

ACM Digital Library Link

Summary: This paper describes a PAC-Amodeus software architectural solution for context-aware systems. The software architectural solution is based on an architecture dedicated to multimodal interaction. Indeed we argue in this paper that several software design issues are common between multimodal systems and context-aware systems. Our architectural solution is intentionally generic, intended to serve as the basis for a wide range of possible systems and compatible with the existing architectural approaches.

[18] ASUR++: A Design Notation for Mobile Mixed Systems Context Dependent Systems / Dubois, Emmanuel / Gray, Philip / Nigay, Laurence Proceedings of 2002 Conference on Human-Computer Interaction with Mobile Devices and Services 2002-09-18 p.123-139

Link to Digital Content at Springer

Summary: In this paper we present a notation, ASUR++, for describing mobile systems that combine physical and digital entities. The notation ASUR++ builds upon our previous one, called ASUR. The new features of ASUR++ are dedicated to handling the mobility of users and enable a designer to express physical relationships among entities involved in the system. The notation and its usefulness are illustrated in the context of the design of an augmented museum gallery.

[19] Guidelines for the Design of Haptic Widgets Haptic Interfaces / Oakley, I. / Adams, A. / Brewster, S. / Gray, P. Proceedings of the HCI'02 Conference on People and Computers XVI 2002-09-02 p.195-212

[20] Teallach: a model-based user interface development environment for object databases / Griffiths, Tony / Barclay, Peter J. / Paton, Norman W. / McKirdy, Jo / Kennedy, Jessie / Gray, Philip D. / Cooper, Richard / Goble, Carole A. / Silva, Paulo Pinheiro da Interacting with Computers 2002 v.14 n.1 p.31-68

Keywords: Model based user interface development; Object databases; User interfaces to databases

Summary: Model-based user interface development environments show promise for improving the productivity of user interface developers, and possibly for improving the quality of developed interfaces. While model-based techniques have previously been applied to the area of database interfaces, they have not been specifically targeted at the important area of object database applications. Such applications make use of models that are semantically richer than their relational counterparts in terms of both data structures and application functionality. In general, model-based techniques have not addressed how the information referenced in such applications is manifested within the described models, and is utilised within the generated interface itself. This lack of experience with such systems has led to many model-based projects providing minimal support for certain features that are essential to such data intensive applications, and has prevented object database interface developers in particular from benefitting from model-based techniques. This paper presents the Teallach model-based user interface development environment for object databases, describing the models it supports, the relationships between these models, the tool used to construct interfaces using the models and the generation of Java programs from the declarative models. Distinctive features of Teallach include comprehensive facilities for linking models, a flexible development method, an open architecture, and the generation of running applications based on the models constructed by designers.

[21] Data Capture for Clinical Anaesthesia on a Pen-based PDA: Is It a Viable Alternative to Paper? / Gardner, M. / Sage, M. / Gray, P. / Johnson, C. Proceedings of the HCI'01 Conference on People and Computers XV 2001-09-10 p.439-456

[22] Dynamic Links for Mobile Connected Context-Sensitive Systems Mobile Interaction / Gray, Philip / Sage, Meurig 2001 Engineering for Human-Computer Interaction 2001-05-11 p.281-297

Link to Digital Content at Springer

Summary: The current generation of mobile context-aware applications must respond to a complex collection of changes in the state of the system and in its usage environment. We argue that dynamic links, as used in user interface software for many years, can be extended to support the change-sensitivity necessary for such systems. We describe an implementation of dynamic links in the Paraglide Anaesthetist's Clinical Assistant, a mobile context-aware system to help anaesthetists perform pre- and post-operative patient assessment. In particular, our implementation treats dynamic links as first class objects. They can be stored in XML documents and transmitted around a network. This allows our system to find and understand new sources of data at run-time.

[23] Modelling and Using Sensed Context Information in the Design of Interactive Applications Context Sensitive Interaction / Gray, Philip / Salber, Daniel 2001 Engineering for Human-Computer Interaction 2001-05-11 p.317-335

Link to Digital Content at Springer

Summary: We present a way of analyzing sensed context information formulated to help in the generation, documentation and assessment of the designs of context-aware applications. Starting with a model of sensed context that accounts for the particular characteristics of sensing, we develop a method for expressing requirements for sensed context information in terms of relevant quality attributes plus properties of the sensors that supply the information. We demonstrate on an example how this approach permits the systematic exploration of the design space of context sensing along dimensions pertinent to software development. Returning to our model of sensed context, we examine how it can be supported by a modular software architecture for context sensing that promotes separation between context sensing, user interaction, and application concerns.

[24] A multi-scaled display technique for PDAs Interactive posters: mobility / Sage, Meurig / Gardner, Martin / Gray, Philip Proceedings of ACM CHI 2001 Conference on Human Factors in Computing Systems 2001-03-31 v.2 p.123-124

ACM Digital Library Link

Summary: The proliferation of small mobile devices with different-sized displays presents a challenge to user interface designers. How can the different display sizes and layouts be accommodated while maintaining a consistent display strategy for users and minimizing the complexity of the interface implementation? We present a multi-scaled display technique developed for use with a palmtop-sized medical clinical assistant.

[25] Haptic perception of virtual roughness Interactive posters: multimodal interaction / McGee, Marilyn Rose / Gray, Philip / Brewster, Stephen Proceedings of ACM CHI 2001 Conference on Human Factors in Computing Systems 2001-03-31 v.2 p.155-156

ACM Digital Library Link

Summary: The texture of a virtual surface can both increase the sense of realism of an object as well as convey information about object identity, type, location, function, and so on. It is crucial therefore that interface designers know the range of textural information available through the haptic modality in virtual environments. The current study involves participants making roughness judgments on pairs of haptic textures experienced through a force-feedback device. The effect of texture frequency on roughness perception is analysed. The potential range and resolution of textural information available through force-feedback interaction are discussed.