Athanasios Plessas

Patterns of usage and context in interaction with communication support applications in mobile devices

Contact lists are one of the most frequently used applications on mobile devices. Users are reluctant to delete or remove contacts from their repositories and as modern smartphones provide an unlimited contact list storage space, these become increasingly large, sometimes measuring several hundred entries. In this paper we present our findings from two experiments with user-subjective and quantitative data concerning the use of mobile contact lists. We examine the role that frequency and recency of usage plays in the determination of a contacts importance, with a view to aid the speed and efficacy of the information seeking and retrieval process during the use of the contact list application.

Urban exploration using audio scents

We describe the design and evaluation of an audio-based mixed reality navigation system that uses the concept of audio scents for the implicit guidance of tourists and visitors of urban areas, as an alternative to turn-by-turn guidance systems. A field trial of our prototype uncovers great potential for this type of implicit navigation and is received positively by our participants. We discuss the technical implementation of our prototype, detailed findings from quantitative and subjective evaluation data gathered during the field trial and highlight possible strands for further research and development.

Web based device independent mobile map applications.: the m-CHARTIS system

A map is one of the most useful media in disseminating spatial information. As mobile devices are becoming increasingly powerful and ubiquitous, new possibilities to access map information are created. However, mobile devices still face severe constraints that limit the possibilities that a mobile map application may offer. We present the m-CHARTIS system, a device independent mobile map application that enables mobile users to access map information from their device.

Application of dimensionality reduction techniques for mobile social context

We propose the application of a dimensionality reduction algorithm that could provide a breakthrough in the efforts to retrieve and present mobile personal information to the user in context.

Frequency and recency context for the management and retrieval of personal information on mobile devices

Abstract As users store increasingly larger amounts of personal information on their mobiles, the task of retrieving such items (e.g., contacts) becomes more difficult. We show that users can be categorized by their communication patterns and that each category benefits differently from supporting contact management applications. By examining mobile user call logs, we show that it is possible to aid retrieval tasks using relatively simple heuristics and algorithms that describe usage context, using solely the dimensions of contact use frequency and recency. We compare and discuss the results of the proposed method applied on two different mobile datasets: a large dataset from NOKIA and a smaller dataset collected by ourselves.

An interface for context-aware retrieval of mobile contacts

Our work discusses a mobile contact retrieval interface which attempts to contextually predict the contacts a user is likely to need access to, in order to facilitate the retrieval process. We compare our prototype implementation with retrieval from traditional applications (contact list and call log) in a preliminary lab experiment and discuss our findings from user behaviour. We conclude with suggestions on how to improve this interface in order to further enhance the retrieval process.

A Dynamic Voice Portal for Delivery of Cultural Content

Many companies today are providing customer services via the Web and the telephone. Demand for providing Web data in audio form is increasing every day. Voice response facilities are used for various kinds of information over the phone: time, weather, horoscopes, lottery results, sports events, news, etc. VoiceXML is an enabling technology for creating a streamlined speech-based interface for web-based information services. Speech technology, as it improves, will become a very natural and powerful interface for ubiquitous access to information. Moreover, VoiceXML applications are available through computers or through the telephone, which is a universal means of communication. In this paper, we describe a dynamic speech-enabled system powered by VoiceXML in which the available information is dynamically generated by PHP.

Automated analysis of greek legislative texts for version control: limitations, caveats and challenges

Greek legislation is produced in the form of texts often containing amendments and references to precedent laws. This structure imposes an increased cognitive complexity and makes it very difficult for citizens to reconstruct the current version of a law. In this paper we present our ongoing work on the automated analysis of Greek legislative texts, aiming to track the evolution of laws through version control systems. We put emphasis on the challenges, the limitations and the encountered problems of our attempt so far, which are due to the unfriendly - from a technological perspective - legislative procedures that are followed.

Assessing Physical Location as a Potential Contextual Cue For Adaptive Mobile Contact Lists

The retrieval of the appropriate contact in order to start a new communication session from the contact repository of mobile devices can be a time consuming procedure since mobile contact lists usually contain hundreds of items. Several researchers have focused in the past on predicting the next contact a user is likely to call, a task that could prove useful in designing adaptive context-aware interfaces for the mobile contact list. Most of the researchers propose several contextual dimensions that could be used to predict the next callee, location being one of them. However, none of these research works have ever examined the impact of location on mobile communications and only few have actually incorporated this contextual dimension on their implementations. In this paper, we examine physical location as a contextual cue for adaptive mobile contact lists by analyzing call logs from the Nokia Mobile Data Challenge dataset. Our work indicates that, contrary to previous literature, the consideration of physical location as a context dimension does not necessarily lead to improvements in the accuracy of predicting the likelihood of communication with contacts for all types of users included in the dataset under review. Finally, we also discuss the possible reasons behind this limited impact.

Field evaluation of context aware adaptive interfaces for efficient mobile contact retrieval

Our paper discusses the implementation and field evaluation of a context-aware mobile contact retrieval application. We examine the performance of our underlying prediction algorithm in real world conditions and report on the suitability of our hybrid interface design, as a replacement for traditional contact retrieval interfaces (e.g. phonebook and recent call list). We find that users are best served by an alphabetical ordering of prediction matches and show that hybrid interface designs can provide a modest benefit in users ability to find a contact, in cases of non-successful predictions. We also discuss users alternative strategies for retrieval in such cases.