Jorge C. S. Cardoso

A Framework for Context-Aware Adaptation in Public Displays

Several approaches for context-aware public display systems exist but none has been able to bridge the gap between the myriad of possible interactive features of a display and adaptation rules for its content. In this paper, we propose a framework of digital footprints generated by the interaction with public displays that can be used as a means to dynamically characterise a place. We describe these footprints, how they can be generated and how they can be used by context-aware display systems to adapt to the social environment of a place.

Probabilistic Estimation of Network Size and Diameter

Determining the size of a network and its diameter are important functions in distributed systems, as there are a number of algorithms which rely on such parameters, or at least on estimates of those values. The Extrema Propagation technique allows the estimation of the size of a network in a fast, distributed and fault tolerant manner. The technique was previously studied in a simulation setting where rounds advance synchronously and where there is no message loss. This work presents two main contributions. The first, is the study of the Extrema Propagation technique under asynchronous rounds and integrated in the Network Friendly Epidemic Multicast (NeEM) framework. The second, is the evaluation of a diameter estimation technique associated with the Extrema Propagation. This study also presents a small enhancement to the Extrema Propagation in terms of communication cost and points out some other possible enhancements. Results show that there is a clear trade-off between time and communication that must be considered when configuring the protocol—a faster convergence time implies a higher communication cost. Results also show that its possible to reduce the total communication cost by more than 18% using a simple approach. The diameter estimation technique is shown to have a relative error of less than 10% even when using a small sample of nodes.

PuReWidgets: a programming toolkit for interactive public display applications

Interaction is repeatedly pointed out as a key enabling element towards more engaging and valuable public displays. Still, most digital public displays today do not support any interactive features. We argue that this is mainly due to the lack of efficient and clear abstractions that developers can use to incorporate interactivity into their applications. As a consequence, interaction represents a major overhead for developers, and users are faced with inconsistent interaction models across different displays. This paper describes the results of a study on interaction widgets for generalized interaction with public displays. We present PuReWidgets, a toolkit that supports multiple interaction mechanisms, automatically generated graphical interfaces, asynchronous events and concurrent interaction. This is an early effort towards the creation of a programming toolkit that developers can incorporate into their public display applications to support the interaction process across multiple display systems without considering the specifics of what interaction modality will be used on each particular display.

M-GIS: Mobile and interoperable access to geographic information

This paper describes an architecture which can be used to access geographic information from mobile devices with limited display and processing characteristics, such as Personal Digital Assistants (PDA) or Mobile Phones. The information may come from different sources leading to an interoperable solution.

Evaluation of a programming toolkit for interactive public display applications

Interaction is repeatedly pointed out as a key enabling element towards more engaging and valuable public displays. Still, most digital public displays today do not support any interactive features. We argue that this is mainly due to the lack of efficient and clear abstractions that developers can use to incorporate interactivity into their applications. As a consequence, interaction represents a major overhead for developers, and users are faced with inconsistent interaction models across different displays. This paper describes the results of the evaluation of a widget toolkit for generalized interaction with public displays. Our toolkit was developed for web-based applications and it supports multiple interaction mechanisms, automatically generated graphical interfaces, asynchronous events and concurrent interaction. We have evaluated the toolkit along various dimensions - system performance, API usability, and real-world deployment - and we present and discuss the results in this paper.

Mobile applications for open display networks: common design considerations

Mobile devices can be a powerful tool for interaction with public displays, but mobile applications supporting this form of interaction are not yet part of our everyday reality. There are no widely accepted abstractions, standards, or practices that may enable systematic interaction between mobile devices and public displays. We envision public displays to move away from a world of closed display networks to scenarios where mobile applications could allow people to interact with the myriad of displays they might encounter during their everyday trips. In this research, we study the key processes involved in this collaborative interaction between public shared displays and mobile applications. Based on the lessons learned from our own development and deployment of 3 applications, and also on the analysis of the interactive features described in the literature, we have identified 8 key processes that may shape this form of interaction: Discovery, Association, Presence Management, Exploration, Interface Migration, Controller, Media Upload and Media Download. The contribution of this work is the identification of these high-level processes and an elicitation of the main design considerations for display networks.

Dimensions of situatedness for digital public displays

Public displays are often strongly situated signs deeply embedded in their physical, social, and cultural setting. Understanding how the display is coupled with on-going situations, its level of situatedness, provides a key element for the interpretation of the displays themselves but is also an element for the interpretation of place, its situated practices, and its social context. Most digital displays, however, do not achieve the same sense of situatedness that seems so natural in their nondigital counterparts. This paper investigates peoples perception of situatedness when considering the connection between public displays and their context. We have collected over 300 photos of displays and conducted a set of analysis tasks involving focus groups and structured interviews with 15 participants. The contribution is a consolidated list of situatedness dimensions that should provide a valuable resource for reasoning about situatedness in digital displays and informing the design and development of display systems.

Opportunities and Challenges of Interactive Public Displays as an Advertising Medium

Advertising is often the key element in the business case for public display networks. However, this is still a limited medium in its support for key advertising concepts, such as targeting or impact assessment. This chapter analyses how the evolution of the medium is creating the opportunity for re-shaping advertising models for Digital Signage. In particular, we consider how the increasing availability of sensing and interaction opportunities may generate the necessary digital footprints that will help to characterise advertising opportunities in Digital Signage and measure impact. A generic footprint model would enable advertising models to be specified at a higher level of abstraction, enabling them to be applied across global display networks composed by very diverse display types, managed by many different entities, and serving many different purposes. We propose a design space that relates the multiple types of digital footprints that can be generated with multiple modes of campaign targeting and impact assessment, providing the ground for a fundamental shift from advertising based on measuring attention to advertising based on active engagement with people.

Creating web-based interactive public display applications with the PuReWidgets toolkit

Interaction is repeatedly pointed out as a key enabling element towards more engaging and valuable public displays. Still, most digital public displays today do not support any interactive features. We believe that this is mainly due to the lack of efficient and clear abstractions that developers can use to incorporate interactivity into their applications. In this demo we present PuReWidgets, a toolkit that developers can use in their public display applications to support the interaction process across multiple display systems, without considering the specifics of what interaction modality will be used on each particular display. PuReWidgets provides high-level widgets to application programmers, and allows users to interact via various interaction mechanisms, such as graphical user interfaces for mobile devices, QR codes, SMS, etc.

Interaction tasks and controls for public display applications

Public displays are becoming increasingly interactive and a broad range of interaction mechanisms can now be used to create multiple forms of interaction. However, the lack of interaction abstractions forces each developer to create specific approaches for dealing with interaction, preventing users from building consistent expectations on how to interact across different display systems. There is a clear analogy with the early days of the graphical user interface, when a similar problem was addressed with the emergence of high-level interaction abstractions that provided consistent interaction experiences to users and shielded developers from low-level details. This work takes a first step in that same direction by uncovering interaction abstractions that may lead to the emergence of interaction controls for applications in public displays. We identify a new set of interaction tasks focused on the specificities of public displays; we characterise interaction controls that may enable those interaction tasks to be integrated into applications; we create a mapping between the high-level abstractions provided by the interaction tasks and the concrete interaction mechanisms that can be implemented by those displays. Together, these contributions constitute a step towards the emergence of programming toolkits with widgets that developers could incorporate into their public display applications.