Christos Efstratiou | University of Kent (original) (raw)

Papers by Christos Efstratiou

Routledge, Apr 22, 2016

The 'smart' in 'Smart Transport' usually refers to technologies, not people. From... more The 'smart' in 'Smart Transport' usually refers to technologies, not people. From cars designed to be 'stackable', through signs that monitor parking spaces, to 'automatic cruise control' systems that 'intelligently' control distances through vehicle-to-vehicle and vehicle-to-infrastructure communication: technologies are key to smart transport. And it is true, people — armoured with status symbol cars and stuck in traffic — often do not behave intelligently, raging at other drivers and pedestrians, taking risks that endanger themselves and others. However, underestimating human intelligence could be a damaging oversight and missed opportunity for transport designers. In this chapter we examine several related aspects of human sense-making practices on the move and explore how these could be productively integrated with smart transport. Starting with a comparison of a 'view from above' and a 'view from on the ground', key aspects of the social logics of our mobile societies become visible. Then, new technologies are already an integral part of the social organisation of mobilities — with some socio-technical innovations that form a kind of parallel universe to the intelligent transport solutions envisaged by engineers and traffic planners. We discuss such 'alternate smart mobilities' through some utopian visions of 'collective intelligence' (Levy 1997) and its more mundane manifestations, including micro-coordination and an emergent digital economy of mobilities, based on crowdsourcing, community sensing, and data mashups. These 'bottom-up' innovations could come together productively with the pervasive 'qualculation' (Thrift 2004) that underpins traffic shaping and other engineering and design efforts around 'intelligent transport systems' (ITS) (COM 2008). Moreover, such a convergence of social and technological innovation could counteract the threat of 'Orwellian' surveillance that is part of a potentially Faustian bargain for more efficiency, convenience, sustainability and security in transport (Dennis and Urry 2009). We conclude with suggestions for mixed mobile research methods that can inform innovation.

Proceedings of the 14th EAI International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services, 2017

2017 IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops), 2017

2016 IEEE International Conference on Pervasive Computing and Communication Workshops (PerCom Workshops), 2016

Abstract. Feature interactions in the original sense of the term (ie within a telecommunications ... more Abstract. Feature interactions in the original sense of the term (ie within a telecommunications domain), have now been the subject of significant research activity for over ten years. This paper considers several different sources of interactions in other domains, arising during the ...

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies, 2019

Early detection of cognitive decline is important for timely intervention and treatment strategie... more Early detection of cognitive decline is important for timely intervention and treatment strategies to prevent further deterioration or development of more severe cognitive impairment, as well as identify at risk individuals for research. In this paper, we explore the feasibility of using data collected from built-in sensors of mobile phone and gameplay performance in mobile-game-based cognitive assessments. Twenty-two healthy participants took part in the two-session experiment where they were asked to take a series of standard cognitive assessments followed by playing three popular mobile games in which user-game interaction data were passively collected. The results from bivariate analysis reveal correlations between our proposed features and scores obtained from paper-based cognitive assessments. Our results show that touch gestural interaction and device motion patterns can be used as supplementary features on mobile game-based cognitive measurement. This study provides initial ...

In this paper, we describe our experiences of developing and evaluating GUIDE, an intelligent ele... more In this paper, we describe our experiences of developing and evaluating GUIDE, an intelligent electronic tourist guide. The GUIDE system has been built to overcome many of the limitations of the traditional information and navigation tools available to city visitors. For example, group-based tours are inherently inflexible with fixed starting times and fixed durations and (like most guidebooks) are constrained by the need to satisfy the interests of the majority rather than the specific interests of individuals. Following a period of requirements capture, involving experts in the field of tourism, we developed and installed a system for use by visitors to Lancaster. The system combines mobile computing technologies with a wireless infrastructure to present city visitors with information tailored to both their personal and environmental contexts. In this paper we present an evaluation of GUIDE, focusing on the quality of the visitor's experience when using the system.

Mobile systems are characterised by the fact that they operate in an environment prone to rapid a... more Mobile systems are characterised by the fact that they operate in an environment prone to rapid and drastic changes [4]. More specifically, attributes like network quality of service (QoS) or power availability can vary significantly compared to non-mobile systems. Mobile applications should be capable of being informed of such changes and should also be able to adapt their behaviour accordingly in order to deliver the best level of service to the end-user. Moreover, future mobile systems should be capable of adapting to general environmental and contextual triggers such as the system's physical location [2]. As presented in [3], current middleware support lacks the required level of control for co-ordinating highly adaptive systems triggered by multiple contextual attributes. Reflection has been suggested as a solution for adaptive middleware [1]. The benefits of being able to open the implementation of the platform, inspect and adapt the behaviour of the system have already b...

Adaptation is an important requirement for mobile applications due to the varying levels of resou... more Adaptation is an important requirement for mobile applications due to the varying levels of resource availability that characterises mobile environments. However without proper control, multiple applications can each adapt independently in response to a range of different adaptive stimuli, causing conflicts or suboptimal performance. In this paper we present a policy driven approach for mobile adaptive systems that can overcome the aforementioned problems. Our system is based on a policy language derived from the Event Calculus logic programming formalism. Important characteristics of our policy language are the support for explicit expressions of time dependencies and the simple and user friendly syntax.

2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 2020

Shape measurement is of great importance for the effective control and safe operation of inflatab... more Shape measurement is of great importance for the effective control and safe operation of inflatable rubber dams. This paper presents for the first time a method to measure the cross-sectional shape of a rubber dam by placing an array of inertial measurement units (IMUs) on the peripheral of the rubber dam. The IMU array measures tangent angles of the dam peripheral by fusing accelerometer and gyroscope measurements. A continuous tangent angle function is derived by interpolating the tangent angles at discrete locations using a cubic spline. Finally, the shape is reconstructed by integrating the tangent angle function along the peripheral of the rubber dam. The performance of the measurement system is validated against a camera on a purpose-built test rig. Experimental results show that the measured and reference shapes are very similar, with a maximum similarity index of 8.5% under typical conditions. In addition, it is demonstrated that the system is robust against node failure by ...

Wireless sensor networks are more and more seen as a solution to large-scale tracking and monitor... more Wireless sensor networks are more and more seen as a solution to large-scale tracking and monitoring applications. However, existing networks are designed to serve a single application and deliver information to one authority; typically the owner of the network. This approach is clearly inefficient considering the high cost of deploying a sensor network. Supporting federation of sensor networks can allow the development of new applications that can access recourses offered by multiple existing sensor networks. This paper discusses the challenges in designing a platform for federated sensor networks.

Pervasive Mob. Comput., 2021

Momentary photography is enjoyed by many smartphone users, especially with the popularity of apps... more Momentary photography is enjoyed by many smartphone users, especially with the popularity of apps such as Snapchat and Instagram. Many traditional positive psychology interventions focus on lengthy writing tasks to express positive emotions experienced during past events, acts of kindness and gratuitous situations. In this work we developed SnapAppy, a smartphone application to integrate momentary photography with traditional intervention methodologies to conduct a month-long positive psychology intervention to improve emotional well-being. A study involving 74 participants aimed to assess whether photo-taking, photo viewing and image contents are correlated with improvements in certain aspects of the participant’s emotional well-being including their mood, affect and satisfaction with life. The results indicated that features including the number of photos, the variety of categories, the effort applied to annotating photos, the number of photos revisited and photos taken of people ...

An increasing number of sensor networks have been deployed to monitor a variety of conditions and... more An increasing number of sensor networks have been deployed to monitor a variety of conditions and situations. At the same time, more and more applications are starting to rely on the data from sensor networks to provide users with (near) real-time information and conditions. This increasing demand of users for accurate information about natural and surrounding phoenomena is creating a business case for application providers.

Keith Cheverst, Christos Efstratiou, Nigel Davies and Adrian Friday Distributed Multimedia Resear... more Keith Cheverst, Christos Efstratiou, Nigel Davies and Adrian Friday Distributed Multimedia Research Group, Lancaster University, e-mail: kc@comp.lancs.ac.uk

Proceedings of the 2021 CHI Conference on Human Factors in Computing Systems

The version in the Kent Academic Repository may differ from the final published version. Users ar... more The version in the Kent Academic Repository may differ from the final published version. Users are advised to check http://kar.kent.ac.uk for the status of the paper. Users should always cite the published version of record.

Adjunct Proceedings of the 2019 ACM International Joint Conference on Pervasive and Ubiquitous Computing and Proceedings of the 2019 ACM International Symposium on Wearable Computers

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies

Traditional methods for screening and diagnosis of alcohol dependence are typically administered ... more Traditional methods for screening and diagnosis of alcohol dependence are typically administered by trained clinicians in medical settings and often rely on interview responses. These self-reports can be unintentionally or deliberately false, and misleading answers can, in turn, lead to inaccurate assessment and diagnosis. In this study, we examine the use of user-game interaction patterns on mobile games to develop an automated diagnostic and screening tool for alcohol-dependent patients. Our approach relies on the capture of interaction patterns during gameplay, while potential patients engage with popular mobile games on smartphones. The captured signals include gameplay performance, touch gestures, and device motion, with the intention of identifying patients with alcohol dependence. We evaluate the classification performance of various supervised learning algorithms on data collected from 40 patients and 40 age-matched healthy adults. The results show that patients with alcohol...

Proceedings of the 2016 ACM International Joint Conference on Pervasive and Ubiquitous Computing Adjunct - UbiComp '16, 2016