Generative artificial intelligence opens new opportunities for accessibility validation. An interesting case is the assessment of alternative text (alt-text) for images. This paper investigates the use of a large language model (LLM) to analyse alt-texts in real e-commerce websites, a domain in which images play an important role and have specific requirements. We present a novel data-driven method and an associated tool that employs tailored prompting strategies to incorporate contextual information when generating and evaluating image descriptions. The approach also supports systematic comparison between human-authored and LLM-generated alt-text. We conducted a user study (N = 16) involving 494 assessments of 157 images, and their corresponding alt-texts extracted from real e-commerce websites. The results show that the proposed solution can provide valid results, supporting its possible integration into existing accessibility validation workflows and authoring tools.

The digital technological evolution is driving exponential growth in connected sensors and objects within smart environments such as homes, workplaces, and social spaces. While automations bring new opportunities, they also introduce risks and challenges. It is essential to provide users with End-User Development (EUD) approaches and tools that let them create, modify, and control automations. In this perspective, a key challenge is enabling non-professional developers to understand and manage security and privacy risks. This paper presents a Systematic Literature Review analysing the intersection of EUD, the Internet of Things, and security and privacy issues, with particular attention to automations and trigger-action programming. We examined the research to identify major risks in smart environments, their sources, and consequences. We analysed approaches and tools designed to mitigate these risks, their user presentation, validation methods, user control levels, and application domains. Our findings offer an overview of current solutions and highlight opportunities for future research into tools that help non-professional developers understand IoT security, usability, and privacy.

Most countries are ageing rapidly, creating significant challenges in providing adequate care to elderly population. Older adults’ care centers face several difficulties in ensuring support able to address their diverse needs, due to several factors including increasing caregiver shortages, high variability in cognitive and health conditions of elderly, and challenges in delivering personalized interventions to them. Additionally, maintaining elderly engagement during cognitive training is often problematic due to the repetitive and impersonal nature of involved tasks. To address these limitations, we carried out a study investigating the use of a humanoid robot to deliver interactive, personalised serious games based on older adults' personal memories, to enhance relevance and engagement for them. The approach has been evaluated in a trial conducted in a center for older adults, involving users with varying cognitive abilities. Results indicated that such personalised games were well received by them, with a positive impact on their experience.

The use of humanoid robots in older adult training has recently started to be considered. We investigated a solution that offers serious games personalised to each individual, to stimulate more interest and participation in cognitive training. In particular, we have studied how to consider personal memories in customising humanoid robot games for Mild Cognitive Impaired (MCI) older adults. For this goal, a prototype platform for collecting and exploiting personal memories in associated games is presented. The memories are exploited by six games designed and implemented in a Pepper robot considering current practices. We report on a mixed-method study consisting of a two-phase trial that involved 15 MCI older adults. The participants first furnished some memories from their past, and then used two game versions regularly for twelve weeks, one personalised and one with general content. We collected both quantitative (through questionnaires and interaction log analysis) and qualitative feedback. The results provide useful information about the robot games’ impact on users and, more generally, for understanding how to introduce robot games based on personal memories in cognitive training programmes.

Internet of Things-enabled home automation is starting to significantly transform our daily lives. Users must be able to configure and coordinate the connected objects in their dwellings to personalise and fully benefit from their potentialities. Trigger-action programming is one relevant approach to enable users to create useful automations. However, current approaches mainly based on visual Web or mobile interfaces have limitations, such as the difficulty in finding and selecting the correct object and associated services. Mobile augmented reality is an interaction modality that can support more direct and usable automation control. In this perspective, the support of a recommendation system can facilitate users in creating personalised automations. This paper presents a system for generating personalised daily automations recommendations and presenting them in a mobile augmented reality solution in order to facilitate their monitoring and creation. Seven classification approaches were assessed on different datasets to determine their ability to provide personalised and context-aware recommendations. We also report a user study (N = 16) showing that the personalised recommendation system improves user performance when creating automations in a trigger action format with a mobile augmented reality editing environment.

Current projections indicate that many countries worldwide are experiencing an increase in the older adult population. Thus, it is important to develop methodologies and tools to improve the quality of life of aging people in terms of their cognitive, social, and physical well-being. An area that is currently showing considerable potential in coping with cognitive decline associated with the aging process is digital serious games. Recent years have witnessed a significant attention increase toward this topic with contributions from several research communities. Although some previous work aimed to synthesize the main findings in related areas, a focused and systematic review categorizing and discussing the literature on cognitive training for older adults is still lacking. To this aim, we selected 113 relevant articles from four international databases. We analyzed them on different relevant dimensions, such as the interactive technologies employed in the games, the activities supported, the user profiles participating in the studies, the factors influencing user engagement and motivation, and the effects of training on the addressed cognitive functions. The analysis of the above dimensions is useful to uncover the factors that distinguish successful cognitive interventions from less effective ones and to facilitate the creation of engaging training programs tailored to the needs of older adults. At the same time, by highlighting promising avenues for further research, the review provides useful indications to researchers and practitioners interested in this field.

Automations can help support the achievement of various types of goals in a smart home. We present an architecture enabling the possibility of supporting user goals consistent with the principles of a circular economy (such as energy saving and waste recycling). It includes meta-design tools for creating automations that better fit user needs and controlling their execution through innovative modalities based on conversational agents and augmented reality, and a home Digital Twin useful for supporting relevant simulations and analytics to understand the potential impact of specific automations on aspects relevant for circular economy.

Cognitive developmental disorders are common in children and can affect various abilities. Attention Deficit/Hyperactivity Disorder (ADHD) is the most prevalent childhood psychiatric condition. This work presents PlayToPickUp, a serious game that aims to stimulate children in relevant cognitive domains (attention and error monitoring). A multidisciplinary team of experts and caregivers from two different centers that support therapeutic activities with such children participated from the games’s inception to the design and the evaluation of the game. Depending on the characteristics and abilities of the player, therapists can customize the game to provide training that best fits the skills and the needs of the child while maintaining the player’s motivation. After its development, the game was used over 2 months “in the wild” by children recruited by the two centers. In one case the children played with it within the regular activities offered by the training center. In the other one, the parents of the children were instructed by caregivers to have the children play the game at home. In the paper, we describe the experience gathered from such two studies run in parallel, discussing the aspects that worked better, those that represented difficulties, and the lesson learnt for future studies.

This paper presents a comprehensive survey on End-User Development for Human-Robot Interaction, examining existing literature to validate findings and identify unexplored areas for future research. It explores the importance of End-User Development in allowing non-expert users to customise robots, covering methodologies, evaluation methods, robot types, and application contexts. The findings reveal various End-User Development approaches, evaluation practices, and robots application domains, leading to discussions on the untapped potential of End-User Development in enhancing Human-Robot Interaction across diverse fields. The document aims to provide groundwork for future studies, highlighting the necessity for new evaluation standards and greater customisation in robotic technologies.

Abstract The proliferation of sensors and smart Internet of Things (IoT) devices in our everyday environments is reshaping our interactions with everyday objects. This change underlines the need to empower non-expert users to easily configure the behaviour of these devices to align with their preferences and habits. At the same time, recent advances in generative transformers, such as ChatGPT, have opened up new possibilities in a variety of natural language processing tasks, enhancing reasoning capabilities and conversational interactions. This paper presents RuleBot + + , a conversational agent that exploits GPT-4 to assist the user in the creation and modification of trigger-action automations through natural language. After an introduction to motivations and related work, we present the design and implementation of RuleBot + + and report the results of the user test in which users interacted with our solution and Home Assistant, one of the most used open-source tools for managing smart environments.

In the last few years, text and voice-based conversational agents have become more and more popular all over the world as virtual assistants for a variety of tasks. In addition, the deployment on the market of many smart objects connected with these agents has introduced the possibility of controlling and personalising the behaviour of several connected objects using natural language. This has the potential to allow people, also those without a technical background, to effectively control and use the wide variety of connected objects and services. In this paper, we present an analysis of how conversational agents have been used to interact with smart environments (such as smart homes). For this purpose, we have carried out a systematic literature review considering publications selected from the ACM and IEEE digital libraries to investigate the technologies used to design and develop conversational agents for IoT settings, including Artificial Intelligence techniques, the purpose that they have been used for, and the level of user involvement in such studies. The resulting analysis is useful to better understand how this field is evolving and indicate the challenges still open in this area that should be addressed in future research work to allow people to completely benefit from this type of solution.

In the last few years, several end-user tools have been designed to help people who are not professional developers in programming their smart environments. However, such tools are often based on structured visual editors providing abstract representations of the available connected sensors and objects, which can be problematic for end users, and do not particularly encourage their participation. This work aims to make the end-user experience of creating everyday automations involving various types of connected sensors and objects more engaging by replacing extensive, static, structured and comprehensive abstract visual tools with more narrowed, relevant, context-sensitive, dynamic, augmented reality-based representations. We present a solution for this purpose that mobile users can exploit through their smartphone. End users can use the smartphone camera to frame the relevant sensor or object through the developed prototype, then get the current automations associated with it, edit their definition, create new ones as well as monitor the automations involving the whole current environment. We also report a first user test of the developed prototype deployed in a home equipped with connected sensors and objects, which yielded positive feedback.

Automations in the context of smart homes have been adopted more and more frequently; thus, users should be able to control them and create automations most suitable to their needs. Current solutions for this purpose are based on visual apps with conceptual representations of possible automation elements. However, they tend to be static, abstract, and detached from the user's real context. In this paper, we propose a novel solution based on mobile augmented reality, which provides situated, dynamic representations associated with the physical objects available in the current users' context while they are freely moving about. It allows direct interaction with the objects of interest, monitoring nearby objects' automations while moving, and creating new automations or modifying existing ones. It also supports users with recommendations of object and service configurations relevant to complete the editing of the new automations. The paper also reports on a user test, which provided positive feedback.

The spread of sensors and intelligent devices of the Internet of Things and their integration in daily environments are changing the way we interact with some of the most common objects in everyday life. Therefore, there is an evident need to provide non-expert users with the ability to customize in a simple but effective way the behaviour of these devices based on their preferences and habits. This paper presents RuleBot, a conversational agent that uses machine learning and natural language processing techniques to allow end users to create automations according to a flexible implementation of the trigger-action paradigm, and thereby customize the behaviour of devices and sensors using natural language. In particular, the paper describes the design and implementation of RuleBot, and reports on a user test and lessons learnt.

This work aims to explore the potentialities of an end-user personalisation platform in industrial settings. In such a context, stakeholders with different roles and competencies collaborate to manage and control an environment where legacy machines coexist and interact with newer ones. Our goal is to provide a rule-based tool that allows end-users to build personalised solutions to respond quickly to the dynamic needs of factories. We report on a case study in the paper factory domain, in which the industrial aspects identified with expert stakeholders through interviews have been simulated and addressed through an extension of a personalisation platform. A first user test of the resulting environment has been carried out with a representative set of users, and has provided useful and encouraging feedback in terms of the potentialities of the proposed approach in industrial contexts.

In this paper, we present the design and the implementation of a cooking game for older adults interacting through a humanoid robot. We discuss the motivations and the requirements that have driven such design and indicate how it has been implemented. The main goal is to stimulate the cognitive resources of older adults in order to limit their decline. For this purpose, we have exploited the multimodal possibilities of the humanoid robot and have identified two robot personalities, which are suitable to improve users' engagement, and thus their potential participation in cognitive training programmes.

Given the growing adoption of Internet of Things (IoT) technologies, several approaches have been presented to enable people to increase their control over their smart devices and provide relevant support. Recommendation systems have been proposed in many domains, but have received limited attention in the area of End-User Development (EUD). We propose a novel approach for formulating recommendations in this area, based on deconstructing trigger-action rules into sequences of elements and the links between them. For this purpose, we propose a solution inspired by methods aimed at addressing the sequence-prediction problem. We have used this approach to provide users with two different types of recommendations: full rules for the one being edited, and parts of rules relevant for the next step to take in order to complete the current rule editing. In this paper, we present the design and a first evaluation of the two different possibilities to generate and display recommendations in a block-based EUD environment for creating automations for IoT contexts.

The Internet of Things is a pervasive technology widely adopted in several contexts ranging from smart homes to automotive cars. In this context, the End User Development is gaining momentum: different solutions support non-technical users to define the smart objects behavior to better satisfy their needs. This workshop aimed to stimulates participants in providing discussions in line with the workshop themes and goals, for example, user mental models, acceptance of EUD solutions, the role of AI in EUD tools, humanoid robots were discussed.

Personalization rules based on the trigger-action paradigm have recently garnered increasing interest in Internet of Things (IoT) applications. However, composing trigger-action rules can be a challenging task for end users, especially when the rules' complexity increases. Users have to decide about various aspects: which triggers and actions to select, how to combine multiple triggers or actions, and whether some previously defined rule can help in the composition process. We propose a visual environment, Block Rule Composer, to address these problems. It consists of a tool for creating rules based on visual blocks, integrated with recommendation techniques in order to provide intelligent support during rule creation. We also report on a first test which provided positive indications and suggestions for further design improvements.

Abstract The recent European legislation emphasizes the importance of enabling people with disabilities to have access to online information and services of public sector bodies. To this regard, automatic evaluation and monitoring of Web accessibility can play a key role for various stakeholders involved in creating and maintaining over time accessible products. In this paper we present the results of elicitation activities that we carried out in a European project to collect experience and feedback from Web commissioners, developers and content authors of websites and web applications. The purpose was to understand their current practices in addressing accessibility issues, identify the barriers they encounter when exploiting automatic support in ensuring the accessibility of Web resources, and receive indications about what functionalities they would like to exploit in order to better manage accessibility evaluation and monitoring.

Automatic support for web accessibility validation needs to evolve for several reasons. The increasingly recognised importance of accessibility implies that various stakeholders, with different expertise, look at it from different viewpoints and have different requirements regarding the types of outputs they expect. The technologies used to support Web application access are evolving along with the associated accessibility guidelines. We present a novel tool that aims to provide flexible and open support for addressing such issues. We describe the design of its main features, including support for recent guidelines and tailored results presentations, and report on first technical and empirical validations that have provided positive feedback.

Automation is finding its way into many parts of everyday life. This is manifested by the increasing opportunities for end users to offload decisions to their home appliances, to hand over control to their cars, to step into automated trains, or to go for shopping at self-checkout stores. Supported by artificial intelligence, emerging automated services are getting closer towards human cognitive functions, as they are integrating analysis and decision based on the processing of large information sets [ 48 ]. In anticipation of the broad impact that these emerging technologies will have on our sphere of life, a reflective and systematic consideration is necessary that leverages their full potential in terms of user experience. While there is a long human factors research tradition on automation, scholars have for long concentrated on highly specialized professional work tasks for trained personnel, such as control center operators or pilots. With technological innovations and new use cases in domains such as transport, home automation, and retail, the goal of designing automation for a broader population has become more important. This transition of automation technology towards the everyday life thus has put the experience of “naïve users” into the center of attention.

In the coming years humanoid robots will be increasingly used in a variety of contexts, thereby presenting many opportunities to exploit their capabilities in terms of what they can sense and do. One main challenge is to design technologies that enable those who are not programming experts to personalize robot behaviour. We propose an end user development solution based on trigger-action personalization rules. We describe how it supports editing such rules and its underlying software architecture, and report on a user test that involved end user developers. The test results show that users were able to perform the robot personalization tasks with limited effort, and found the trigger-action environment usable and suitable for the proposed tasks. Overall, we show the potential for using trigger-action programming to make robot behaviour personalization possible even to people who are not professional software developers.

The main goal of this work is to better understand how vibrotactile feedback obtained through wearable actuators can support indoor orientation in unfamiliar buildings. We designed different wearable vibrotactile prototypes (two wristbands, a flexible/rigid glove, one wristband, a cap and two-bands), and we analysed them in a preliminary test with 7 users to identify the design aspects that are most relevant for a solution guiding a person indoor. We describe the design and its evaluation with 36 users, discussing the results that can be useful for developers who want to use this technology within applications that need support for indoor orientation.

Seamless interaction across personal and public devices is still problematic. Gestural interaction can be a useful support for this purpose, but how to exploit it in cross-device frameworks is still unclear. We present an elicitation study aiming to contribute in identifying the most intuitive single or combined gestures that people can perform to interact with cross-device applications. This study led us to the definition of a possible gesture vocabulary for the typical interactive tasks in such applications. We then applied the resulting preferred gestures in an example cross-device Web application exploiting it. This application has finally been tested in order to evaluate the gestures' actual usability in cross-device interactions.

Remote monitoring services should be strongly personalised to the specific needs, preferences, abilities and motivations of elderly, a population segment whose characteristics can largely vary and even dynamically evolve over time for the same individual, depending on changing needs and usage contexts. We present a demo showing how a platform supporting End User Development (EUD) of context-dependent applications has been customized for remotely assisting elderly people at home. The user-editable personalisation features are specified by using trigger-action rules. The platform has been integrated with various sensors and appliances, and an application for remotely monitoring older adults at home. The resulting environment supports the possibility of creating trigger-action rules that can actually be executed when relevant sensors indicate that specific events or conditions occurred.

This study aims to understand the potential of using vibrotactile stimulation for indoor orientation in complex, unfamiliar buildings. Four vibrotactile prototypes have been analysed and tested in initial trials in order to investigate the benefits and the problems of each solution. The main goal of this study is to reach a better understanding of the design aspects that make a vibrotactile solution intuitive and effective.

Abstract This paper presents the architecture of a decision support environment for large-scale assessment of compliance against web accessibility recommendations and legislations. The proposed decision support environment aims at integrating, extending and further enhancing existing web accessibility solutions making them customizable to the needs of different stakeholders, transferable to different sectors in web and mobile environments, in order to minimize costs and development time by also increasing scalability and improving their accessibility and usability.

The increasing availability of sensors and intelligent objects enables new functionalities and services. In the Ambient Assisted Living (AAL) domain, such technologies can be used for monitoring and reasoning about the older people behavior to detect possible anomalous situations, which could be a sign of the next onset of chronic illness or initial physical and cognitive decline. We propose an approach to detecting abnormal behavior by developing a profiling strategy (in which task models specify the normal behavior), which can also work in case of rare anomaly data. Events corresponding to the user behavior is detecting by a middleware software(Context Manager). Afterward, our algorithm compares the planned and actual behavior to identify if any deviation occurred and also defines to which category the anomaly belongs. The resulting environment should be able to generate multi-modal actions (i.e alarms, reminders) based on detected anomalous behavior, aiming to provide useful support to improve older people well-being.

With today's technology, elderly can be supported in living independently in their own homes for a prolonged period of time. Monitoring and analyzing their behavior in order to find possible unusual situation helps to provide the elderly with health warnings at the proper time. Current studies are focusing on the elderly daily activity and the detection of anomalous behaviors aiming to provide the older people with remote support. To this aim, we propose a real-time solution which models the user daily routine using a task model specification and detects relevant contextual events occurred in their life through a context manager. In addition, by a systematic validation through a system that automatically generates wrong sequences of tasks, we show that our algorithm is able to find behavioral deviations from the expected behavior at different times by considering the extended classification of the possible deviations with good accuracy.

Remote usability evaluation enables the possibility of analysing users' behaviour in their daily settings. We present a method and an associated tool able to identify potential usability issues through the analysis of client-side logs of mobile Web interactions. Such log analysis is based on the identification of specific usability smells. We describe an example set of bad usability smells, and how they are detected. The tool also allows evaluators to add new usability smells not included in the original set. We also report on the tool use in analysing the usability of a real, widely used application accessed by forty people through their smartphones whenever and wherever they wanted.

In order to exploit the wide availability of public displays and personal devices on the mass market at affordable prices it is important to provide developers with frameworks that ease obtaining cross-device user interfaces able to exploit such device ecosystems. We present the design and implementation of a Web framework for the development of cross-device user interfaces able to take advantage of both personal devices and public displays, and support various types of gestures and their combinations in such multi-device environments. We introduce the design space addressed, describe the framework functionality, its application interface and run-time support, show some example applications, and report on a first test with developers.

User interface modeling tools can play a useful role for engineering interactive systems. However, little is known about how these tools are used, the strategies and workarounds employed, and whether usability problems are encountered. To start answering this question, we run a user study with software engineers carrying out task modeling activities. The analysis of the data generated by an instrumented CTTE and an eye-tracker uncovers five workflows that illustrate how the task model hierarchy is populated and edited, operators are added to tasks, and when model consistency is checked. These findings inform design implications for task modeling tools and formulate hypotheses for future work.

Our life is characterized by the presence of a multitude of interactive devices and smart objects exploited for disparate goals in different contexts of use. Thus, it is impossible for application developers to predict at design time the devices and objects users will exploit, how they will be arranged, and in which situations and for which objectives they will be used. For such reasons, it is important to make end users able to easily and autonomously personalize the behaviour of their Internet of Things applications, so that they can better comply with their specific expectations. In this paper, we present a method and a set of tools that allow end users without programming experience to customize the context-dependent behaviour of their Web applications through the specification of trigger-action rules. The environment is able to support end-user specification of more flexible behaviour than what can be done with existing commercial tools, and it also includes an underlying infrastructure able to detect the possible contextual changes in order to achieve the desired behaviour. The resulting set of tools is able to support the dynamic creation and execution of personalized application versions more suitable for users’ needs in specific contexts of use. Thus, it represents a contribution to obtaining low threshold/high ceiling environments. We also report on an example application in the home automation domain, and a user study that has provided useful positive feedback.

research-article Free Access Share on Editorial: End-User Development for the Internet of Things Editors: Panos Markopoulos Eindhoven University of Technology Eindhoven University of TechnologyView Profile , Jeffrey Nichols Google GoogleView Profile , Fabio Paternò CNR-ISTI CNR-ISTIView Profile , Volkmar Pipek University of Siegen University of SiegenView Profile Authors Info & Claims ACM Transactions on Computer-Human InteractionVolume 24Issue 2April 2017 Article No.: 9pp 1–3https://doi.org/10.1145/3054765Published:06 April 2017Publication History 19citation867DownloadsMetricsTotal Citations19Total Downloads867Last 12 Months75Last 6 weeks28 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

In the field of Web usability evaluation, one potential effective approach is the usage of logging tools for remote usability analysis (i.e. tools capable of tracking and recording the users' activities while they interact with a Web site), and then presenting the recorded data to usability experts in such a way to support detection of possible usability problems. In the design of such automated tools, in addition to the problems related to user behavior recording, another important issue is the choice of meaningful visual representations in order to support the usability expert analysis.

Current authoring environments provide the possibility of developing user interfaces with limited adaptation capacities. The most widely adopted tools follow the responsive design approach and allow developers to obtain user interfaces that can adapt mainly to the screen size and orientation. We present a solution able to support development of user interfaces able to adapt to the various types of contextual events (that can be related to users, devices, environments, and social relationships), with the added possibility of distributing the user interface elements across multiple devices. The context-dependent behavior is modelled through trigger / action rules, and can even be applied to Web applications that were not originally designed to be context-aware. This paper describes the design and main features of the novel authoring environment and reports on a first user study.

In general, Interaction Design is considered important for achieving usable user interfaces, but in terms of specification languages for this purpose, there is not much agreement. In contrast, for more specific Interaction Design in the context of automated (G)UI generation, Task Models are the most widely used approach. The more recent Discourse-based approach in this context is much less widely understood. It focuses on the specification of (classes of) dialogues in contrast to tasks for modeling activities that can be performed by the user or the application (system). We identified a duality of Interaction Design according to these approaches to high-level modeling for GUI generation, which we explain and elaborate in this paper. In this course, we contrast the different models, which specify largely corresponding abstractions of Interaction Design, but from different views and with a different design philosophy. As a consequence, mutual understanding of these different modeling approaches should be improved. Based on this duality, suggestions for mutual improvements can be made, so that the tool-box of interaction designers wishing to have GUIs generated automatically from their models should become more general and flexible.

The Service-Oriented Computing (SOC) paradigm is currently being adopted by many developers, as it promises the construction of applications through reuse of existing Web Services (WSs). However, current SOC tools produce applications that interact with users in a limited way. This limitation is overcome by model-based Human-Computer Interaction (HCI) approaches that support the development of applications whose functionality is realized with WSs and whose User Interface (UI) is adapted to the user's context. Typically, such approaches do not consider various functional issues, such as the applications' semantics and their syntactic robustness in terms of the WSs selected to implement their functionality and the automation of the service discovery and selection processes. To this end, we propose a model-driven design method for interactive service-based applications that is able to consider the functional issues and their implications for the UI. This method is realized by a semiautomatic environment that can be integrated into current model-based HCI tools to complete the development of interactive service front-ends. The proposed method takes as input an HCI task model, which includes the user's view of the interactive system, and produces a concrete service model that describes how existing services can be combined to realize the application's functionality. To achieve its goal, our method first transforms system tasks into semantic service queries by mapping the task objects onto domain ontology concepts; then it sends each resulting query to a semantic service engine so as to discover the corresponding services. In the end, only one service from those associated with a system task is selected, through the execution of a novel service concretization algorithm that ensures message compatibility between the selected services.

In this work we present an environment able to support users in seamless access to Web applications in multi-device contexts. The environment supports dynamic push and pull of interactive Web applications, or parts of them, across desktop and mobile devices while preserving their state.

The effort and time required to develop user interface models has been one of the main limitations to the adoption of model-based approaches, which enable intelligent processing of user interface descriptions. In this paper, we present a tool to perform reverse engineering of interactive dynamic Web applications into a model-based framework able to describe them at various abstraction levels. We indicate how information in HTML, HTML 5, CSS, Ajax and JavaScript is transformed into such logical framework, which facilitates adaptation to other types of interactive devices. We also discuss how this reverse engineering tool has been exploited in an environment for run-time adaptation or migration of interactive Web applications to various devices in ubiquitous use cases.

In ubiquitous environments migratory interactive applications allow users to perform their tasks continuously across various devices. Users can push and pull migratory Web applications from one device to another for various reasons. However, the flexibility of such pervasive applications raises various security issues, such as the risk of theft of private information from the migrated user interfaces or the intrusion of malicious versions of the applications replacing the original ones. In this paper, we analyse such risks and present a number of solutions to address them in a client/server-based solution for supporting secure migration of interactive Web applications.

Widespread usage of powerful touch-based mobile devices enables the creation of tools that will allow end users to create their own mobile applications. In this paper, we introduce the Puzzle framework, which supports a visual authoring tool for opportunistically creating mobile applications in touch-based mobile phones. Puzzle focuses on users without programming experience and enables them to playfully experiment and create mobile applications. Puzzle applications can include access to web-services, native phone functions and interactive objects. In the paper, we report on its current architecture and user interface.

This article discusses how human–computer interaction (HCI) models can support the development of interactive applications based on Web services. It also introduces a specific method exploiting such models for this purpose and the associated tool support. An example application of the method for an educational scenario is presented. The results of an early test of the development environment are reported as well. Lastly, some conclusions are drawn along with indications for future work.

We discuss our solution for partial Web migration from large screens to mobile devices. It is based on multiple UI abstraction levels and some transformations that allow the migration of selected UI components to another device.

Services are becoming more and more widely used. When designing interactive applications based on services one important issue is how to identify those services most relevant for the application functionalities. The proposed approach takes as input a task model, which includes the user's view of the interactive system, and an ontology capturing the application domain, and automatically discovers a set of ordered service descriptions for each system task of the model. The discovered descriptions can be used in order to invoke a particular service operation that fulfils a task's required functionality. In this way, the whole application functionality can be realized by a set of service operations without writing a single line of code. As a result, the application development time is significantly reduced and it is possible to complete the development of interactive front-ends by integrating our solution in existing model-based HCI approaches.

In this paper, we present a method and the associated tool support able to exploit Web services in model-based user interface development, starting with the results of a task analysis phase, and using the content of Web service annotations. The resulting environment is a powerful support for developing multi-device interactive applications based on Web Services, since it is able to generate usable service front ends specified in a variety of implementation languages. This is achieved through connecting pre-existing Web services with the task model of the interactive application that has to be built. Then, the task model is used as a starting point for the generation of corresponding user interfaces descriptions at different abstraction levels, through a number of transformations that aim to preserve the usability of the corresponding models or implementations. The environment also allows designers to specify and customize such transformations among various levels of detail of the user interface description.

One important aspect of ubiquitous environments is to provide users with the possibility to freely move about and continue to interact with the available applications through a variety of interactive devices such as cell phones, PDAs, desktop computers, intelligent watches or digital television sets. Migratory applications are able to follow the user by sensing changes in the user's context and adapting to available devices, ideally without interrupting the user experience. However, applications themselves must contain functions to monitor context information, coordinate a migration, handle application adaptation and interact with the user during the migration process. To make life easier for developers and users of migratory applications, we propose an integrated Migration Service Platform (MSP), where all the common migration functions are centralised. We show how the platform is realised as middleware that contains a server for the central functions and lightweight client-side running on the end-user devices. We show how migratory applications can interact with the platform and thereby do not have to contain migration functions themselves. By using the platform, they can register and be controlled by the platform to enrich the user experience with the application. We describe the challenges following the centralisation of a migration platform that can support different types of applications, both games and business applications, implemented with either web-technologies or as component-based applications.

Ubiquitous environments call for innovative uses of existing applications. In this paper we present our solution for partial Web migration: it allows users to interactively select parts of existing interfaces and have them migrate to a target device. The underlying supporting platform exploits logical user interface descriptions and a set of transformations. This environment is particularly useful for supporting mobile users accessing complex Web applications, such as various emerging mash-ups. We also show an example of use of our solution in a widespread Web application, and report on a user test.

Nowadays users are surrounded by environments characterized by an abundance of devices and appliances that they use for carrying out their everyday activities. In order to improve user experience, the surrounding environments should be intelligent enough to allow users to freely move around and be able to perform their tasks in a continuous manner, without forcing them to start their interactive session from scratch at each device change. In this paper, we present an agent-based solution able to support migration of interactive applications among various devices, including digital TVs and mobile devices, and therefore useful for users freely moving about in the home and outdoor. The aim is to provide users with a seamless and supportive environment for ubiquitous access in multi-device contexts of use. The proposed open architecture for migratory user interfaces (UIs) is composed of several agents. It exploits their functionalities and is able to automatically build logical descriptions of existing interactive Web applications and then dynamically generate UIs that are adapted to various types of target devices and implementation languages, including non-Web languages, with the state updated to the point at which it was left off in the previous device.

Link annotation with the accessibility level of the target Web page is an adaptive navigation support technique aimed at increasing blind users' orientation in Web sites. In this work, the accessibility level of a page is measured by exploiting data from evaluation reports produced by two automatic assessment tools. These tools support evaluation of accessibility and usability guideline-sets. As a result, links are annotated with a score that indicates the conformance of the target Web page to blind user accessibility and usability guidelines. A user test with 16 users was conducted in order to observe the strategies they followed when links were annotated with these scores. With annotated links, the navigation paradigm changed from sequential to browsing randomly through the subset of those links with high scores. Even if there was not a general agreement on the correspondence between scores and user perception of accessibility, users found annotations helpful when browsing through links related to a given topic.

In this paper, we propose UbiCicero, a multi-device, location-aware museum guide able to opportunistically exploit large screens when users are nearby. Various types of games are included in addition to the museum and artwork descriptions. The mobile guide is equipped with an RFID reader, which detects nearby tagged artworks. By taking into account context-dependent information, including the current user position and behaviour history, as well as the type of device available, more personalised and relevant information is provided to the user, enabling a richer overall experience. We also present example applications of this solution and then discuss the results of first empirical tests performed to evaluate the usefulness and usability of the enhanced multi-device guide.

One important evolution in software applications is the spread of service-oriented architectures in ubiquitous environments. Such environments are characterized by a wide set of interactive devices, with interactive applications that exploit a number of functionalities developed beforehand and encapsulated in Web services. In this article, we discuss how a novel model-based UIDL can provide useful support both at design and runtime for these types of applications. Web service annotations can also be exploited for providing hints for user interface development at design time. At runtime the language is exploited to support dynamic generation of user interfaces adapted to the different devices at hand during the user interface migration process, which is particularly important in ubiquitous environments.

While several solutions for desktop user interface adaptation for mobile access have been proposed, there is still a lack of solutions able to automatically generate mobile versions taking semantic aspects into account. In this paper, we propose a general solution able to dynamically build logical descriptions of existing desktop Web site implementations, adapt the design to the target mobile device, and generate an implementation that preserves the original communications goals while taking into account the actual resources available in the target device. We describe the novel transformations supported by our new solution, show example applications and report on first user tests.

In this paper, we present a solution for supporting vibrotactile feedback in mobile museum guides for blind users. To this end, we have designed and implemented a hardware/software module, which can be easily plugged into current PDAs to assist blind users in orientation. The solution, which comprises a two-channels haptic module as well as vocal support, has been exploited for moving through tagged objects. We also report on a user evaluation carried out with a number of blind users.

Available accessibility guidelines do not necessarily guarantee usable Web sites, particularly when specific groups of users with special needs are considered. We have identified 15 Web design criteria aiming to provide integrated support of accessibility and usability for vision-impaired users. In this article, we present the results of a study investigating whether the application of such guidelines for vision-impaired users can actually improve their task performance when accessing Web applications. We report on two user tests, both involving vision-impaired users, that aim to provide empirical validation of the design criteria. During each test, users had to access and navigate two versions of a Web site, one version supporting the selected design criteria and one obtained with traditional techniques. Our results indicate that the 15 design criteria improved Web site usability both quantitatively and qualitatively by reducing the navigation time needed to perform the assigned tasks and by making the Web sites easier to navigate for blind and low-vision users.

Customization of Web-based applications is often considered a designer skill rather than an end-user need. However, there is an ongoing shift to end-user-centred technology, and even users with poor or no skill in Web-based languages may feel the need to customize Web applications according to their preferences. Although Web authoring environments have an increasing number of features, the challenge of providing end-users with the ability to easily customize entire Web applications still remains unsolved. In this paper, we propose an intelligent approach to customizing Web-based applications. Customizations rules are automatically inferred by the system from changes that users supply as examples. They remain as long-term knowledge that can be applied to support future interactions, thus minimizing the amount of authoring that end-users need to do for this purpose. In order to better understand the implications of the user’s modifications, they are analysed using the logical descriptions of the corresponding Web pages.

The availability of mobile and stationary devices opens up new challenges to support users in several contexts. Here we present a multi-device environment to support cooperation among museum visitors through games. In particular, we present a design and the associated implementation for using a combination of PDAs and public displays to enhance the learning experience in a museum setting by using game playing interactions. The basic assumption is to use the mobile devices for individual game play, and the situated displays for synchronized public views of shared game play; the individual game play contributes to the shared game.

The technological evolution is making multimodal technology available to the mass market with increased reliability. However, developing multimodal interfaces is still difficult and there is a lack of authoring tools for this purpose, especially when multi-device environments are addressed. In this paper, we present a method and a supporting tool for authoring user interfaces with various ways to combine graphics and voice in multi-device environments. The tool is based on the use of logical descriptions and provides designers and developers with support to manage the underlying complexity, make and modify design choices, and exploit the possibilities offered by multimodality.

This paper presents a new interaction technique - scan and tilt - aiming to enable a more natural interaction with mobile museum guides. Our work combines multiple modalities - gestures, physical selection, location, graphical and voice. In particular, physical selection is obtained by scanning RFID tags associated with the artworks, and tilt gestures are used to control and navigate the user interface and multimedia information. We report on how it has been applied to a mobile museum guide in order to enhance the user experience, providing details on a first user test carried out on our prototype.

The increasing need to check Web site accessibility has stimulated interest in tools to aid the various activities involved. While some tools for this purpose already exist, we believe that there is a demand for making their support more flexible. In particular, there is often a need for validation of multiple sets of guidelines, repairing Web pages and providing better reports for the evaluators. In this paper, we discuss such issues and how we have addressed them in the design of MAGENTA, our new tool for supporting inspection-based evaluation of accessibility and usability guidelines.

This paper describes an environment able to support migratory multimodal interfaces in multidevice environments. We introduce the software architecture and the device-independent languages used by our tool, which provides services enabling users to freely move about, change device and continue the current task from the point where they left off in the previous device. Our environment currently supports interaction with applications through graphical and vocal modalities, either separately or together. Such applications are implemented in Web-based languages. We discuss how the features of the device at hand, desktop or mobile, are considered when generating the multimodal user interface.

In this paper, we present a solution for dynamic generation of Web user interfaces that can dynamically migrate among different platforms. The solution is based on a migration/proxy server able to automatically convert a desktop service into a service accessible from a different platform, such as a mobile one. This solution can support new environments where users can freely move about and change interaction device while still continuing task performance and accessing the application in a usable manner.

This paper aims to provide a discussion of how model-based approaches and related tools have been used to address important issues for obtaining usable interactive software and the new challenges for this research area. The paper provides an analysis of the logical descriptions that can be used in the design of interactive systems and how they can be manipulated in order to obtain useful results. This type of approach has recently raised further interest in the ubiquitous computing field for supporting the design of multi-device interfaces. The new challenges currently considered are mainly in the area of end-user development, ambient intelligence, and multimodal interfaces.

The goal of this work is to provide users immersed in a multi-platform environment with the possibility of interacting with an application while freely moving from one device to another. We describe the solution that we have developed for a service to support platform-aware runtime migration for Web applications. This allows users interacting with an application to change device and continue their interaction from the same point. The service performs the migration of the application taking into account its runtime state and adapting the application interface to the features of the target platforms. The service is optimized for applications developed through a model-based, multiple-level approach. The intelligence of the adaptive interfaces resides in the migration server, which adapts data collected at runtime from their original format to the format best fitting the features of the target platform. We also indicate how it is possible to extend this result in order to support partial migration and synergistic access, by which a part of the user interface is kept on one device during runtime and the remaining part is moved to another with different characteristics.

The ever-increasing availability of new types of devices raises a number of issues for user interface designers and interactive software developers. We have designed and developed a tool (TERESA), which can be helpful when designing applications accessible through various device types.

The increasing availability of new types of interaction platforms raises a number of issues for designers and developers. There is a need for new methods and tools to support development of nomadic applications, which can be accessed through a variety of devices. We present a solution, based on the use of three levels of abstractions, that allows designers to focus on the relevant logical aspects and avoid dealing with a plethora of low-level details. We have defined a number of transformations able to obtain user interfaces from such abstractions, taking into account the available platforms and their interaction modalities while preserving usability. The transformations are supported by an authoring tool, TERESA, which provides designers and developers with various levels of automatic support and several possibilities for tailoring such transformations to their needs.

Model-based approaches can be useful when designing nomadic applications, which can be accessed through multiple interaction platforms. Various models and levels of abstraction can be considered in such approaches. The lack of automatic tool support has been the main limitation to their use. We present a tool, TERESA, supporting top-down transformations from task models to abstract user interfaces and then to user interfaces for different types of interaction platforms (such as mobile phones or desktop systems). It allows designers to keep a unitary view of the design of a given nomadic application. Moreover, the tool provides support for obtaining effective interfaces for each type of platform available, taking into account the consequent differences in terms of tasks and their performance

In this paper we present and discuss the integration of tools for the development and analysis of human–computer interaction models with formal verification techniques. We explain the method that we have developed and the tools that we have integrated for this purpose, and discuss how the resulting environment is more effective for designers of interactive applications than using current formal verification techniques alone. The main result is that designers can take advantage of the functionality of model-checking tools while still working with representations of the relevant models that they are familiar with in their practice. Thus, we show how tools can support such an approach and what design choices have been made to improve the usability of such an environment, allowing even people with little background in formal methods to use it.

In this paper we present a method and the related tool for analysing Web site code in order to automatically reconstruct the underlying logical interaction design. Such design is represented through task models that describe how activities should be performed to reach users' goals. The models also include a specification of the objects that should be manipulated to accomplish such tasks. We also discuss how the result of this reverse engineering process can be provided as input to a number of tools for various purposes (model analysis, usability evaluation, user interface redesign for different interactive platforms).

This editorial paper introduces an emerging and important area for human–computer interaction research, which concerns interaction with mobile devices. The design of interactive mobile applications should differ from that of traditional desktop applications. To this aim, the paper discusses some concepts and models that help to understand the new challenges as well as recently introduced techniques that can be useful for exploiting the characteristics of these devices. Lastly, tool support for the design of nomadic applications is considered, taking into account the potential contexts of use, with particular attention to the platform features.

The wide variety of devices currently available, which is bound to increase in the coming years, poses a number of issues for the design cycle of interactive software applications. Model-based approaches can provide useful support in addressing this new challenge. In this paper we present and discuss a method for the design of nomadic applications showing how the use of models can support their design. The aim is to enable each interaction device to support the appropriate tasks users expect to perform and designers to develop the various device-specific application modules in a consistent manner.

In this paper, we describe a tool able to perform intelligent analysis of Web browser logs using the information contained in the task model of the application. We show how this approach supports remote usability evaluation of Web sites.

In this paper we present a method, and the related tool, for analysing Web site code in order to automatically reconstruct the underlying logical interaction design. Such a design is represented through task models that describe how activities should be performed to reach user's goals. We also discuss how the result of this reverse engineering process can be provided as input to a tool for usability evaluation.

While task modeling and task-based design are entering into current practice in the design of interactive software applications, there is still a lack of tools supporting the development and analysis of task models. Such tools should provide developers with ways to represent tasks, including their attributes and objects and their temporal and semantic relationships, to easily create, analyze, and modify such representations and to simulate their dynamic behavior. In this paper, we present a tool, CTTE, that provides thorough support for developing and analyzing task models of cooperative applications, which can then be used to improve the design and evaluation of interactive software applications. We discuss how we have designed this environment and report on trials of its use.

The use of models has entered into current practice when developing various types of software product. However, there is a lack of methods able to use the information contained in relevant models concerning human-computer interaction for supporting the design and development of user interfaces. In this paper, we propose a method for using information contained in formally represented task models in order to support the design of interactive applications, with particular attention to those applications where both usability and safety are the main concern. Examples taken from our experience in a case study from the domain of Air Traffic Control are introduced and further discussed to explain how the method can be applied.

No abstract available.

There are few computer-aided approaches that provide a model-based usability evaluation using empirical data. This paper proposes a solution that allows designers to remotely evaluate the usability of interactive software applications with the support of automatic tools, empirical data, and the task model of the application.

Users interact with museum application interfaces for many reasons. There are various types of users, who want to perform various tasks, in various contexts, that can access the same Web site. Thus, it is important to have user interfaces able to adapt to these different user requirements to facilitate the accomplishment of the desired goals. Most current interfaces to museum information do not take into account this variety of types of users, thus providing interfaces that some users find confusing to achieve their goals. In this article we discuss the various possible levels of support that can be given to different users during navigation of museum information. In particular, we focus our attention on how to obtain adaptable and adaptive interfaces using the web site for the Marble Museum, which we have designed and developed, as a source of examples for our discussion of possible solutions.

In this paper we discuss the design and implementation of hypermedia able to adapt to different types of usage. Our work is based on a method whose main elements are: a strong user involvement, the identification of different types of users, and the application of task models to support the design and development of hypermedia. Different task models are associated with different types of users. We show examples of the approach proposed taken from a case study where museum information is considered.

In this article we present a method for evaluating and comparing design options for allocating communication media. The method pays particular attention to how such options support cooperation in an interactive safety-critical system. The comparison is performed using three sets of criteria based on task performance, analysis of user deviations and consequent hazards, and coordination. The explicit emphasis on hazards and communication issues, using actual tasks to guide the evaluation, ensures that designers attention is focused on the interactions where problems are likely to occur. We describe an application of the method to the design of access to new communication technology in an air traffic control environment.

Software is increasingly being used to control safety-critical systems. Much research since Levesons fundamental article Software Safety: Why, What, and How (ACM Computing Surveys 18, 2 (1986), pp. 125163) has focused on ways to reduce or avoid software failures. However, the reliability of even the best-engineered software can be undermined by its user interface. Indeed, interface design for safety-critical interactive systems poses special challenges to the human-computer interaction community. This special issue addresses the challenge of analyzing, designing, and building reliable and usable safety-critical interactive systems. From a pragmatic point of view a safety-critical system is a system for which the cost of a failure is more important than the cost of developing the system. Safety-critical interactive systems add the human dimension to a software system by putting control into the hands of a human operator. Prominent examples of such control systems include nuclear power plants, railways systems, airplane cockpits, and military systems. Recent years have seen much effort put into the reengineering of the control system that is well represented in this special issueair traffic control. When compared to office automation systems, human-computer interac-tion for safety-critical interactive systems is both familiar and different. For instance, the management of a functionality like undo, that can be seen as a usability issue in an office automation system, can become a critical functionality when the user interacts with a safety-critical system. The three articles in this special issue provide three snapshots for how human-computer interaction issues play out in the broader field of safety-critical interactive systems. In the first article, Is Paper Safer? The Role of Flight Strips in Air Traffic Control, Wendy Mackay provides a detailed ethnographic study on how air traffic controllers work. As in Mackays article, the case study entails en-route air traffic control. An important contribution of this article is a method for an integrated analysis of three important methods of this field: task performance, analysis of user deviation and consequent hazard, and cooperation among users. Each of the three articles deals with the analysis and design phases of safety-critical interactive systems. If changes are to be made to large, complex, safety-critical control systems, the changes must be made early in the development lifecycle, where redesign in response to identified problems is feasible.This special issue arose from a CHI98 Workshop organized by Palanque and Paterno´ (“Designing User Interfaces for Safety-Critical Systems”, SIGCHI Bulletin 30, 4 ). The three articles included in this special issue were selected from more than a score of papers received. The editors thank and acknowledge their debt to the many qualified external reviewers from several countries who have helped select and improve (through their comments) the contributions in this special issue.

This paper presents and discusses the use of Semantic Multimedia Presentation Templates which capture presentation structures that are suitable for communicating semantic data relationships occurring across many applications. The identification of the space of the possible presentation templates along with criteria to evaluate them that depend on the current task, data cardinality and other aspects, is very useful for supporting the automatic generation of effective query result multimedia presentations.

The main goal of the work is to propose a method to evaluate user interfaces using task models and logs generated from a user test of an application. The method can be incorporated into an automatic tool which gives the designer information useful to evaluate and improve the user interface. These results include an analysis of the tasks which have been accomplished, those which failed and those never tried, user errors and their type, time related information, task patterns among the accomplished tasks, and the available tasks from the current state of the user session. This information is also useful to an evaluator checking whether the specified usability goals have been accomplished.

One of the advantages of using formal methods in the design of human–computer interfaces is the possibility to reason about user interface properties. Model checking techniques provide a useful support to this end. This paper discusses the possibilities of verifying the properties of user interfaces and related problems, such as when the dialogue specification has an infinite number of states. We provide an example of a set of general user interfaces properties, and we show how these properties can be tailored for specific cases and thus be used as a framework to evaluate the design of the interactive application considered.

This work presents an approach to the design of the software component of an Interactive System, which supports the generation of automatic task-oriented help.Help can easily be generated from the abstract formal specification of the associated system without any further effort.The architectural description is obtained in a taskclriven way, where tasks are specified by indicating temporal ordering constraints using operators of a concurrent formal notation.The association of user tasks with software interaction objects, which inherit constraints of related tasks, gives the information to structure task-oriented help in an immediate way.The help given is thus more expressive with a consequent improvement in the usability of an Interactive System.

Abstract In this paper the design of a visual program editor and its specification using formal grammars are discussed. We consider an environment to specify, analyse and execute visual programs for a Geographical Information System (GIS). The lack of sophisticated user interfaces is one of the major drawbacks to Geographical Information Systems, particularly for people without a sound background in computer science. The use of a visual language approach is useful in order to hide the plethora of basic GIS functions, while providing ready‐ to‐use tools to solve users' tasks. The visual environment provides users with higher level interfaces; it is based on the module concept, which is conceived as a software building block that implements a solution to a general basic task and is presented to the user through an interactive frame. Complex GIS queries can be carried out by interconnecting modules into flow networks, using a direct manipulation approach.

Abstract Although tools for developing graphical user interfaces are becoming increasingly popular, they do not usually highlight precisely which key elements developers should take into account. This still entails considerable expertise in developing user interfaces. In this paper we present an approach to overcome these problems. Our approach is based on a model for interaction objects and a corresponding design space. This is supported by a toolkit where the available interaction objects are initially classified by their semantics whereas in most current toolkits they are investigated by their appearance. This facilitates designers and developers in identifying the interactors needed in order to obtain an Interactive System supporting user tasks.

Abstract This paper is motivated by the emerging ISO/IEC Reference Model for Computer Graphics (CGRM) and the revision of the ISO/IEC computer graphics standard, the Graphical Kernel System (GKS). The paper explores the use of the CGRM as a framework for structuring a specification of apart of the current draft of the revised GKS and the use of the LOTOS formal description technique for specifying graphics systems.

Abstract This paper describes the specification of an input model for graphics systems. The initial aim of the work reported in this paper was to revise the input model adopted by graphics standards by means of formal specification techniques in order to acquire a deep knowledge of its capabilities, to eventually discover errors and to develop improvements. Taking into account similar works done in this area by others and considering a number of major issues related to input recently discussed within the graphics community, a new model is being proposed that addresses the very key concepts of parallelism, extensibility and reconfigurability. The model is based upon composition operations defined over basic components specified as a set of concurrent processes. Composition operations and process definitions have been formally specified by using the LOTOS notation and investigated by means of the LOTOS Interactive Tools Environment. In the first part of the paper, the input model of graphics standards is shortly examined in the light of the results so far achieved by related works on formal specification of computer graphics systems. Subsequently, an improved model is presented. Finally, its capability of simulating the traditional operating modes of logical input devices and a methodology for defining new operating modes is demonstrated.

In this paper we present the preliminary results from a work aiming to the formal specification af a model suitable for the description of interactive graphics program within the framework defined by the Reference Model for Computer Graphics Systems, actually under development within the International Organization for Standardization. The architecture defined by the Computer Graphics Reference Model, at its actual state of development, is shortly presented with particular attention paid to the concepts used in the paper. Following, the components of a basic interaction are identified and described as a set of independent communicating processes, referred to as an interactor. The relationships between interactors are described in terms of the communication between their component processes by using ECSP-like constructs.