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UBICOMP Tables of Contents: 01020304050607080910111213-113-214-114-215

Proceedings of the 2008 International Conference on Uniquitous Computing

Fullname:Proceedings of the 10th International Conference on Ubiquitous Computing
Editors:Hee Yong Youn; We-Duke Cho; Joe McCarthy; James Scott; Woontack Woo
Location:Seoul, Korea
Dates:2008-Sep-21 to 2008-Sep-24
Standard No:ISBN 1-60558-136-4, 978-1-60558-136-1; ACM DL: Table of Contents hcibib: UBICOMP08
Links:Conference Home Page
  1. Activity sensing
  2. Portable and wearable
  3. Location sensing
  4. Ubicomp methods and tools
  5. Security and privacy
  6. Design and ethnography
  7. Context-based systems
  8. Location-aware applications
  9. Augmenting everyday life

Activity sensing

Accurate activity recognition in a home setting BIBAKFull-Text 1-9
  Tim van Kasteren; Athanasios Noulas; Gwenn Englebienne; Ben Kröse
A sensor system capable of automatically recognizing activities would allow many potential ubiquitous applications. In this paper, we present an easy to install sensor network and an accurate but inexpensive annotation method. A recorded dataset consisting of 28 days of sensor data and its annotation is described and made available to the community. Through a number of experiments we show how the hidden Markov model and conditional random fields perform in recognizing activities. We achieve a timeslice accuracy of 95.6% and a class accuracy of 79.4%.
Keywords: activity recognition, annotation, dataset, probabilistic models, sensor networks
Discovery of activity patterns using topic models BIBAKFull-Text 10-19
  Tâm Huynh; Mario Fritz; Bernt Schiele
In this work we propose a novel method to recognize daily routines as a probabilistic combination of activity patterns. The use of topic models enables the automatic discovery of such patterns in a user's daily routine. We report experimental results that show the ability of the approach to model and recognize daily routines without user annotation.
Keywords: activity recognition, wearable computing
Dealing with sensor displacement in motion-based onbody activity recognition systems BIBAKFull-Text 20-29
  Kai Kunze; Paul Lukowicz
We present a set of heuristics that significantly increase the robustness of motion sensor-based activity recognition with respect to sensor displacement. In this paper placement refers to the position within a single body part (e.g, lower arm). We show how, within certain limits and with modest quality degradation, motion sensor-based activity recognition can be implemented in a displacement tolerant way. We first describe the physical principles that lead to our heuristic. We then evaluate them first on a set of synthetic lower arm motions which are well suited to illustrate the strengths and limits of our approach, then on an extended modes of locomotion problem (sensors on the upper leg) and finally on a set of exercises performed on various gym machines (sensors placed on the lower arm). In this example our heuristic raises the displaced recognition rate from 24% for a displaced accelerometer, which had 96% recognition when not displaced, to 82%.
Keywords: fitness exercises, motion sensors, opportunistic activity recognition, sensor displacement
Real world activity recognition with multiple goals BIBAKFull-Text 30-39
  Derek Hao Hu; Sinno Jialin Pan; Vincent Wenchen Zheng; Nathan Nan Liu; Qiang Yang
Recognizing and understanding the activities of people from sensor readings is an important task in ubiquitous computing. Activity recognition is also a particularly difficult task because of the inherent uncertainty and complexity of the data collected by the sensors. Many researchers have tackled this problem in an overly simplistic setting by assuming that users often carry out single activities one at a time or multiple activities consecutively, one after another. However, so far there has been no formal exploration on the degree in which humans perform concurrent or interleaving activities, and no thorough study on how to detect multiple goals in a real world scenario. In this article, we ask the fundamental questions of whether users often carry out multiple concurrent and interleaving activities or single activities in their daily life, and if so, whether such complex behavior can be detected accurately using sensors. We define several classes of complexity levels under a goal taxonomy that describe different granularities of activities, and relate the recognition accuracy with different complexity levels or granularities. We present a theoretical framework for recognizing multiple concurrent and interleaving activities, and evaluate the framework in several real-world ubiquitous computing environments.
Keywords: activity recognition, concurrent activities, conditional random field, interleaving activities
Improving the recognition of interleaved activities BIBAKFull-Text 40-43
  Joseph Modayil; Tongxin Bai; Henry Kautz
We introduce Interleaved Hidden Markov Models for recognizing multitasked activities. The model captures both inter-activity and intra-activity dynamics. Although the state space is intractably large, we describe an approximation that is both effective and efficient. This method significantly reduces the error rate when compared with previously proposed methods. The algorithm is suitable for mobile platforms where computational resources may be limited.
Keywords: activity recognition, hidden Markov model, interleaved activities

Portable and wearable

Lifelogging memory appliance for people with episodic memory impairment BIBAKFull-Text 44-53
  Matthew L. Lee; Anind K. Dey
Lifelogging technologies have the potential to provide memory cues for people who struggle with episodic memory impairment (EMI). These memory cues enable the recollection of significant experiences, which is important for people with EMI to regain a sense of normalcy in their lives. However, lifelogging technologies often collect an overwhelmingly large amount of data to review. The best memory cues need to be extracted and presented in a way that best supports episodic recollection. We describe the design of a new lifelogging system that captures photos, ambient audio, and location information and leverages both automated content/context analysis and the expertise of family caregivers to facilitate the extraction and annotation of a salient summary consisting of good cues from the lifelog. The system presents the selected cues for review in a way that maximizes the opportunities for the person with EMI to think deeply about these cues to trigger memory recollection on his own without burdening the caregiver. We compare our system with another review system that requires the caregiver to repeatedly guide the review process. Our self-guided system resulted in better memory retention and imposed a smaller burden on the caregiver whereas the caregiver-guided approach provided more opportunities for caregiver interaction.
Keywords: Alzheimer's disease, caregiver burden, information overload, lifelogging, memory impairment
Flowers or a robot army?: encouraging awareness & activity with personal, mobile displays BIBAKFull-Text 54-63
  Sunny Consolvo; Predrag Klasnja; David W. McDonald; Daniel Avrahami; Jon Froehlich; Louis LeGrand; Ryan Libby; Keith Mosher; James A. Landay
Personal, mobile displays, such as those on mobile phones, are ubiquitous, yet for the most part, underutilized. We present results from a field experiment that investigated the effectiveness of these displays as a means for improving awareness of daily life (in our case, self-monitoring of physical activity). Twenty-eight participants in three experimental conditions used our UbiFit system for a period of three months in their day-to-day lives over the winter holiday season. Our results show, for example, that participants who had an awareness display were able to maintain their physical activity level (even during the holidays), while the level of physical activity for participants who did not have an awareness display dropped significantly. We discuss our results and their general implications for the use of everyday mobile devices as awareness displays.
Keywords: ambient display, awareness, calm technology, field experiment, fitness, glanceable display, mobile phone, personal mobile display, persuasive technology, physical activity
Online everywhere: evolving mobile instant messaging practices BIBAKFull-Text 64-73
  Donald J. Patterson; Christopher Baker; Xianghua Ding; Samuel J. Kaufman; Kah Liu; Andrew Zaldivar
In this paper we report on the results of a large scale user survey investigating the status setting and interruption management behavior of mobile instant messaging (IM) users with existing systems. The motivation for this study was to inform the design of interface tools that support users by setting contextually appropriate awareness messages. Our results demonstrate that many desktop IM practices have been appropriated by mobile laptop users, but in the face of increasingly situated computer usage and an "always online" culture, several frictions are emerging between desktop and mobile practices. We find that common assumptions about IM users and the established awareness cues are failing and users are frequently embarrassed and interrupted with negative and sometimes threatening consequences.
Keywords: IM, awareness, instant messaging, location disclosure, mobile computing, online status, presence, privacy
A quantitative investigation of inertial power harvesting for human-powered devices BIBAKFull-Text 74-83
  Jaeseok Yun; Shwetak Patel; Matt Reynolds; Gregory Abowd
We present an empirical study of the long-term practicality of using human motion to generate operating power for body-mounted consumer electronics and health sensors. We have collected a large continuous acceleration dataset from eight experimental subjects going about their normal daily routine for 3 days each. Each subject is instrumented with a data collection apparatus that simultaneously logs 3-axis, 80Hz acceleration data from six body locations. We use this dataset to optimize a first-principles physical model of the commonly used velocity damped resonant generator (VDRG) by selecting physical parameters such as resonant frequency and damping coefficient to maximize harvested power. Our results show that with reasonable assumptions on size, mass, placement, and efficiency of VDRG harvesters, most body-mounted wireless sensors and even some consumer electronics devices, may be powered continuously and indefinitely from everyday motion.
Keywords: human-powered devices, inertial power harvesting
It's in your eyes: towards context-awareness and mobile HCI using wearable EOG goggles BIBAKFull-Text 84-93
  Andreas Bulling; Daniel Roggen; Gerhard Tröster
In this work we describe the design, implementation and evaluation of a novel eye tracker for context-awareness and mobile HCI applications. In contrast to common systems using video cameras, this compact device relies on Electrooculography (EOG). It consists of goggles with dry electrodes integrated into the frame and a small pocket-worn component with a DSP for real-time EOG signal processing. The device is intended for wearable and standalone use: It can store data locally for long-term recordings or stream processed EOG signals to a remote device over Bluetooth. We describe how eye gestures can be efficiently recognised from EOG signals for HCI purposes. In an experiment conducted with 11 subjects playing a computer game we show that 8 eye gestures of varying complexity can be continuously recognised with equal performance to a state-of-the-art video-based system. Physical activity leads to artefacts in the EOG signal. We describe how these artefacts can be removed using an adaptive filtering scheme and characterise this approach on a 5-subject dataset. In addition to explicit eye movements for HCI, we discuss how the analysis of unconscious eye movements may eventually allow to deduce information on user activity and context not available with current sensing modalities.
Keywords: context-awareness, electrooculography (EOG), eye gestures, eye tracking, human-computer interaction (HCI), wearable computing

Location sensing

Wideband powerline positioning for indoor localization BIBAKFull-Text 94-103
  Erich P. Stuntebeck; Shwetak N. Patel; Thomas Robertson; Matthew S. Reynolds; Gregory D. Abowd
Fingerprinting techniques for indoor localization have been widely explored. A particular approach by Patel et al. suggested leveraging of the residential powerline as the signaling mechanism for a domestic location capability. In this paper, we critically examine that initial work, called powerline positioning (PLP). We find the proposed technique lacking in temporal stability, requiring frequent and undesired recalibration in some environments. We also determine that there is no a priori method to determine a pair of signaling frequencies that will reliably work in any space. We propose a wideband approach to PLP (WPLP) that injects up to 44 different frequencies into the powerline. We show that this WPLP approach improves upon overall positioning accuracy, demonstrates greatly improved temporal stability and has the added advantage of working in commercial indoor spaces.
Keywords: context awareness, fingerprinting, localization, location tracking
CILoS: a CDMA indoor localization system BIBAKFull-Text 104-113
  Waqas ur Rehman; Eyal de Lara; Stefan Saroiu
CILoS is an indoor localization system based on CDMA mobile phone signal fingerprinting. CDMA networks vary their transmission power to accommodate fluctuations in network load. This affects signal intensity and therefore limits the practicality of traditional fingerprinting approaches based on receiver signal strength (RSSI) measurements. Instead, CILoS uses fingerprints of signal delay that are robust to cell resizing. We demonstrate that CILoS achieves a median accuracy of 5 meters, and compares favourably to RSSI fingerprinting systems. We highlight the significance of wide fingerprints, constructed through scanning multiple channels, for achieving high localization accuracy. We also show that our system can accurately differentiate between floors of a multifloor building.
Keywords: localization system, location, radio fingerprinting
Pedestrian localisation for indoor environments BIBAKFull-Text 114-123
  Oliver Woodman; Robert Harle
Location information is an important source of context for ubiquitous computing systems. This paper looks at how a foot-mounted inertial unit, a detailed building model, and a particle filter can be combined to provide absolute positioning, despite the presence of drift in the inertial unit and without knowledge of the user's initial location. We show how to handle multiple floors and stairways, how to handle symmetry in the environment, and how to initialise the localisation algorithm using WiFi signal strength to reduce initial complexity.
   We evaluate the entire system experimentally, using an independent tracking system for ground truth. Our results show that we can track a user throughout a 8725 m2 building spanning three floors to within 0.5m 75% of the time, and to within 0.73 m 95% of the time.
Keywords: inertial tracking, localisation, particle filters
Localization in mobile ad hoc networks using cumulative route information BIBAKFull-Text 124-133
  Jahyoung Koo; Jiyoung Yi; Hojung Cha
Discovering the location of the mobile nodes carried by people is important issue for many sensor applications. Several localization techniques have been proposed, but human mobility patterns and collaboration between mobile nodes have been seldom considered. In this paper, we propose a mobile node localization system based on collaboration and route information that characterizes human mobility. To validate the feasibility of our approach, the proposed system is implemented and experiments are conducted on real routes and to evaluate various scenarios, simulation experiment was also conducted.
Keywords: collaboration, mobile node localization, wireless sensor networks

Ubicomp methods and tools

Interactionist AI and the promise of ubicomp, or, how to put your box in the world without putting the world in your box BIBAKFull-Text 134-143
  Lucian Leahu; Phoebe Sengers; Michael Mateas
In many ways, the central problem of ubiquitous computing -- how computational systems can make sense of and respond sensibly to a complex, dynamic environment laden with human meaning -- is identical to that of Artificial Intelligence (AI). Indeed, some of the central challenges that ubicomp currently faces in moving from prototypes that work in restricted environments to the complexity of real-world environments -- e.g. difficulties in scalability, integration, and fully formalizing context -- echo some of the major issues that have challenged AI researchers over the history of their field. In this paper, we explore a key moment in AI's history where researchers grappled directly with these issues, resulting in a variety of novel technical solutions within AI. We critically reflect on six strategies from this history to suggest technical solutions for how to approach the challenge of building real-world, usable solutions in ubicomp today.
Keywords: AI-completeness, interactionist AI, reflective HCI
On using existing time-use study data for ubiquitous computing applications BIBAKFull-Text 144-153
  Kurt Partridge; Philippe Golle
Governments and commercial institutions have conducted detailed time-use studies for several decades. In these studies, participants give a detailed record of their activities, locations, and other data over a day, week, or longer period. These studies are particularly valuable for the ubicomp community because of the large number of participants (often the tens of thousands), and because of their public availability. In this paper, we show how to use the data from these studies to provide validated and cheap (although noisy) classifiers, baseline metrics, and other benefits for activity inference applications.
Keywords: activity inference, diary studies, evaluation methodologies, mobile computing, time-use studies, ubiquitous computing
Using wearable sensors and real time inference to understand human recall of routine activities BIBAKFull-Text 154-163
  Predrag Klasnja; Beverly L. Harrison; Louis LeGrand; Anthony LaMarca; Jon Froehlich; Scott E. Hudson
Users' ability to accurately recall frequent, habitual activities is fundamental to a number of disciplines, from health sciences to machine learning. However, few, if any, studies exist that have assessed optimal sampling strategies for in situ self-reports. In addition, few technologies exist that facilitate benchmarking self-report accuracy for routine activities. We report on a study investigating the effect of sampling frequency of self-reports of two routine activities (sitting and walking) on recall accuracy and annoyance. We used a novel wearable sensor platform that runs a real time activity inference engine to collect in situ ground truth. Our results suggest that a sampling frequency of five to eight times per day may yield an optimal balance of recall and annoyance. Additionally, requesting self-reports at regular, predetermined times increases accuracy while minimizing perceived annoyance since it allows participants to anticipate these requests. We discuss our results and their implications for future studies.
Keywords: ESM, empirical evaluation, experience sampling method, recall accuracy, self-reports, survey frequency, user study
Using visualizations to increase compliance in experience sampling BIBAKFull-Text 164-167
  Gary Hsieh; Ian Li; Anind Dey; Jodi Forlizzi; Scott E. Hudson
Experience sampling method (or ESM) is a common data collection method to understand user behavior and to evaluate ubiquitous computing technologies. However, ESM studies often demand too much time and commitment from participants, which leads to attrition and low compliance among participants. We introduce a new approach called experience sampling with feedback or ES+feedback that improves compliance by giving feedback to participants through various visualizations. Providing feedback to users makes the information personally relevant and increases the value of the study to participants, which increases their compliance. Our exploratory study shows that ES+feedback increases the compliance rate by 23%.
Keywords: empirical studies, experience sampling, visualizations
Towards the automated social analysis of situated speech data BIBAKFull-Text 168-171
  Danny Wyatt; Jeff Bilmes; Tanzeem Choudhury; James A. Kitts
We present an automated approach for studying fine-grained details of social interaction and relationships. Specifically, we analyze the conversational characteristics of a group of 24 individuals over a six-month period, explore the relationship between conversational dynamics and network position, and identify behavioral correlates of tie strengths within a network. The ability to study conversational dynamics and social networks over long time scales, and to investigate their interplay with rigor, objectivity, and transparency will complement the traditional methods for scientific inquiry into social dynamics. They may also enable socially aware ubiquitous computing systems that are cognizant of and responsive to the user's engagement with her social environment.
Keywords: machine learning, social network analysis, wearable computing

Security and privacy

Design and implementation of a secure wireless mote-based medical sensor network BIBAKFull-Text 172-181
  Kriangsiri Malasri; Lan Wang
A medical sensor network can wirelessly monitor vital signs of humans, making it useful for long-term health care without sacrificing patient comfort and mobility. For such a network to be viable, its design must protect data privacy and authenticity given that medical data are highly sensitive. We identify the unique security challenges facing such a sensor network and propose a set of resource-efficient mechanisms to address these challenges. Our solution includes (1) a novel two-tier scheme for verifying the authenticity of patient data; (2) an ECC-based secure key exchange protocol to set up shared keys between sensor nodes and base stations; and (3) symmetric encryption/decryption for protecting data confidentiality and integrity. We have implemented the proposed mechanisms on a wireless mote platform and our results confirm their feasibility.
Keywords: authenticity, health monitoring, privacy, sensor network
An empirical investigation of concerns of everyday tracking and recording technologies BIBAKFull-Text 182-191
  David H. Nguyen; Alfred Kobsa; Gillian R. Hayes
This paper presents an exploration and analysis of attitudes towards everyday tracking and recording technologies (e. g., credit cards, store loyalty cards, store video cameras). Interview participants reported being highly concerned with information privacy. At the same time, however, they also reported being significantly less concerned regarding the use of everyday technologies that have the capabilities to collect, process, and disseminate personal information. We present results from this study that both identify and begin to explain this discrepancy.
Keywords: everyday technologies, privacy, recording, retail, tracking, user study
Reflecting on the invisible: understanding end-user perceptions of ubiquitous computing BIBAKFull-Text 192-201
  Erika Shehan Poole; Christopher A. Le Dantec; James R. Eagan; W. Keith Edwards
How can designers of ubiquitous computing technologies ensure that they understand the non-functional needs, values, and expectations of end-users? In this paper, we use a qualitative method from public policy to elicit reflective feedback from end-users about technologies that they may not yet have used nor fully comprehend. Our study uncovers information about end-user perceptions of RFID, including a range of "folk theories" held by the public about this technology, and their associations of it with certain social groups and values. We argue that these perceptions can limit technological adoption, and conclude with a discussion of challenges for the design and deployment of ubiquitous computing systems.
Keywords: evaluation techniques, folk theories, qualitative methods, social implications, technology adoption
Protecting your daily in-home activity information from a wireless snooping attack BIBAKFull-Text 202-211
  Vijay Srinivasan; John Stankovic; Kamin Whitehouse
In this paper, we first present a new privacy leak in residential wireless ubiquitous computing systems, and then we propose guidelines for designing future systems to prevent this problem. We show that we can observe private activities in the home such as cooking, showering, toileting, and sleeping by eavesdropping on the wireless transmissions of sensors in a home, even when all of the transmissions are encrypted. We call this the Fingerprint and Timing-based Snooping (FATS) attack. This attack can already be carried out on millions of homes today, and may become more important as ubiquitous computing environments such as smart homes and assisted living facilities become more prevalent. In this paper, we demonstrate and evaluate the FATS attack on eight different homes containing wireless sensors. We also propose and evaluate a set of privacy preserving design guidelines for future wireless ubiquitous systems and show how these guidelines can be used in a hybrid fashion to prevent against the FATS attack with low implementation costs.
Keywords: activity monitoring, side channel privacy attacks, wireless fingerprinting
MobiRate: making mobile raters stick to their word BIBAKFull-Text 212-221
  Daniele Quercia; Stephen Hailes; Licia Capra
To share services, portable devices may need to locate reputable in-range providers and, to do so, they may exchange ratings with each other. However, providers may well tweak ratings to their own advantage. That is why we have designed a new decentralized mechanism (dubbed MobiRate) with which portable devices store ratings in (local) tamper-evident tables and check the integrity of those tables through a gossiping protocol. We evaluate the extent to which MobiRate reduces the impact of tampered ratings and consequently locates reputable service providers. We do so using real mobility and social network data. We also assess computational and communication costs of MobiRate on mobile phones.
Keywords: distributed reputation (trust) systems, mobile systems

Design and ethnography

The heterogeneous home BIBAKFull-Text 222-231
  Ryan Aipperspach; Ben Hooker; Allison Woodruff
Due to several recent trends, the domestic environment has become more homogeneous and undifferentiated. Drawing on concepts from environmental psychology, we critique these trends. We propose heterogeneity as a new framework for domestic design, and we present design sketches that illustrate how ubiquitous computing technologies can interact with the domestic environment to create a more varied and restorative environment. This work speaks to a number of core issues in ubiquitous computing, such as how the increased presence of devices impacts quality of life, the desirability or undesirability of ubiquitous temporal and spatial availability of devices, and the advantages and disadvantages of device convergence ("all-in-one" devices) versus device proliferation (single application devices).
Keywords: architecture, domestic technology, interaction design
Plastic: a metaphor for integrated technologies BIBAKFull-Text 232-241
  Tye Rattenbury; Dawn Nafus; Ken Anderson
Ubiquitous computing research has recently focused on 'busyness' in American households. While these projects have generated important insights into coordination and communication, we think they overlook the more spontaneous and opportunistic activities that surround and support the scheduled ones. Using data from our mixed-methods study of notebook and ultra-mobile PC use, we argue for a different perspective based on a metaphor of 'plastic'. 'Plastic' captures the way technologies, specifically computers, have integrated into the heterogeneous rhythms of daily life. Plastic technologies harmonize with and support daily life by filling opportunistic gaps, shrinking and expanding until interrupted, not demanding conscious coordination, supporting multitasking, and by deferring to external contingencies.
Keywords: attention, busyness, personal computers, plastic, temporality
Getting to green: understanding resource consumption in the home BIBAKFull-Text 242-251
  Marshini Chetty; David Tran; Rebecca E. Grinter
Rising global energy demands, increasing costs and limited natural resources mean that householders are more conscious about managing their domestic resource consumption. Yet, the question of what tools Ubicomp researchers can create for residential resource management remains open. To begin to address this omission, we present a qualitative study of 15 households and their current management practices around the water, electricity and natural gas systems in the home. We find that in-the-moment resource consumption is mostly invisible to householders and that they desire more real-time information to help them save money, keep their homes comfortable and be environmentally friendly. Designing for domestic sustainability therefore turns on improving the visibility of resource production and consumption costs as well as supporting both individuals and collectives in behavior change. Domestic sustainability also highlights the caveat of potentially creating a green divide by making resource management available only to those who can afford the technologies to support being green. Finally, we suggest that the Ubicomp community can contribute to the domestic and broader sustainability agenda by incorporating green values in designs and highlight the challenge of collecting data on being green.
Keywords: domestic conservation, residential resource consumption, sustainability
Designing sociable IT for public use BIBAKFull-Text 252-261
  Steinar Kristoffersen; Ingunn Bratteberg
Service providers increasingly use self-service systems, such as kiosk and automata that offer faster and more flexible service. Most of us are familiar with appliances for buying and validating tickets, purchasing soft drinks or getting the newspaper. We book tables in restaurants and hire cars using hotel lobby kiosks. Unfortunately, many such systems confuse and annoy their users. Thus, information technology design for the public space poses distinct challenges. Yet, it is relatively unmapped within our field. Based on an ethnographic study of the purchase and validation of ticketless travel for an airport train, this paper shows how such systems need an extended framework of usability principles, which goes beyond well-known interaction design guidelines.
Keywords: design guidelines, ethnography, public IT, usability

Context-based systems

Mixed-initiative conflict resolution for context-aware applications BIBAKFull-Text 262-271
  Choonsung Shin; Anind K. Dey; Woontack Woo
A number of technologies have contributed to automatically resolving resource conflicts between multiple users in a smart space. However, such systems eliminate the users' ability to perform this conflict resolution by themselves, which they actually prefer to do in certain circumstances. Since both resolution approaches have their merits, we propose a mixed-initiative conflict resolution system, which combines automatic conflict resolution with mediated, or user-driven, resolution by exploiting contextual information in context-aware applications. An evaluation of our system found that users prefer to use a mediated resolution approach when their preferences about outcome are very different from others', but have no preferred method when their preferences about outcome are similar to others'.
Keywords: conflict resolution, context-aware computing, mixed-initiative, smart space
A context-aware patient safety system for the operating room BIBAKFull-Text 272-281
  Jakob E. Bardram; Niels Nørskov
Most context-aware systems have been designed for non-safety-critical environments such as offices, museums, and university campuses. This paper argues that context-awareness can be used for safety-critical systems too. But since the consequences of errors or failures in safety-critical systems are potentially severe, we should have a high degree of confidence in these systems. We present the design, implementation, and evaluation of a context-aware patient safety and information system (CAPSIS) designed for use during surgery. Specifically, our study indicates that CAPSIS could improve patient safety in the operating room. More generally, the paper suggests that context-aware technologies offer a promising step forward in the design of safety-critical systems.
Keywords: CAPSIS, context-aware computing, operating room, pervasive healthcare, safety-critical systems
Deploy spontaneously: supporting end-users in building and enhancing a smart home BIBAKFull-Text 282-291
  Fahim Kawsar; Tatsuo Nakajima; Kaori Fujinami
This paper explores system issues for involving end users in constructing and enhancing a smart home. In support of this involvement we present an infrastructure and a tangible deployment tool. Active participation of users is essential in a domestic environment as it offers simplicity, greater user-centric control, lower deployment costs and better support for personalization. Our proposed infrastructure provides the foundation for end user deployment utilizing a loosely coupled framework to represent an artefact and its augmented functionalities. Pervasive applications are built independently and are expressed as a collection of functional tasks. A runtime component, FedNet maps these tasks to corresponding service provider artefacts. The tangible deployment tool uses FedNet and allows end users to deploy and control artefacts and applications only by manipulating RFID cards. Primary advantages of our approach are two-fold. Firstly, it allows end users to deploy ubicomp systems easily in a Do-it-Yourself fashion. Secondly, it allows developers to write applications and to build augmented artefacts in a generic way regardless of the constraints of the target environment. We describe an implemented prototype and illustrate its feasibility in a real life deployment session by the end users. Our study shows that the end users might be involved in deploying future ubicomp systems if appropriate tools and supporting infrastructure are provided.
Keywords: augmented artefact, end user deployment, pervasive application, system infrastructure
Schema matching for context-aware computing BIBAKFull-Text 292-301
  Wenwei Xue; Hungkeng Pung; Paulito P. Palmes; Tao Gu
Context-aware computing is a key paradigm of ubiquitous computing in which applications automatically adapt their operations to dynamic context data from multiple sources. Managing a number of distributed sources, a middleware that facilitates the development of context-aware applications must provide a uniform view of all these sources to the applications. Local schemas of context data from individual sources need to be matched into a set of global schemas in the middleware, upon which applications can issue context queries to acquire data. In this paper, we study this problem of schema matching for context-aware computing. We propose a multi-criteria algorithm to determine candidate attribute matches between two schemas. The algorithm adaptively adjusts the priorities of different criteria based on previous matching results to improve the efficiency and accuracy of succeeding operations. We further develop an algorithm to categorize a new local schema into one of the global schemas whenever possible via a shared attribute dictionary. Our results based on schemas from real-world websites demonstrate the good matching accuracy achieved by our algorithms.
Keywords: context attributes, context awareness, context schemas, middleware, schema matching, ubiquitous computing

Location-aware applications

The potential for location-aware power management BIBAKFull-Text 302-311
  R. K. Harle; A. Hopper
This paper explores the use of location-awareness to dynamically optimise the energy consumption of an office. It makes use of high-accuracy location data collected over 60 days randomly selected from a year in a commercial environment to evaluate the potential for energy savings and to motivate techniques that might be used.
   The results suggest that the energy expended on lighting and fast-response systems could have been cut by 50%; that 75.8% of the average user's working day was spent in their office; and that around 140Wh per PC per day could have been saved, compared to a policy that had machines on for the entirety of the working day. We also find inconsistent office usage that would make optimising slow response systems much harder.
Keywords: context-aware, energy efficiency, location-aware, power management
Understanding mobility based on GPS data BIBAKFull-Text 312-321
  Yu Zheng; Quannan Li; Yukun Chen; Xing Xie; Wei-Ying Ma
Both recognizing human behavior and understanding a user's mobility from sensor data are critical issues in ubiquitous computing systems. As a kind of user behavior, the transportation modes, such as walking, driving, etc., that a user takes, can enrich the user's mobility with informative knowledge and provide pervasive computing systems with more context information. In this paper, we propose an approach based on supervised learning to infer people's motion modes from their GPS logs. The contribution of this work lies in the following two aspects. On one hand, we identify a set of sophisticated features, which are more robust to traffic condition than those other researchers ever used. On the other hand, we propose a graph-based post-processing algorithm to further improve the inference performance. This algorithm considers both the commonsense constraint of real world and typical user behavior based on location in a probabilistic manner. Using the GPS logs collected by 65 people over a period of 10 months, we evaluated our approach via a set of experiments. As a result, based on the change point-based segmentation method and Decision Tree-based inference model, the new features brought an eight percent improvement in inference accuracy over previous result, and the graph-based post-processing achieve a further four percent enhancement.
Keywords: GPS, GeoLife, infer transportation mode, machine learning, recognize human behavior
Navigate like a cabbie: probabilistic reasoning from observed context-aware behavior BIBAKFull-Text 322-331
  Brian D. Ziebart; Andrew L. Maas; Anind K. Dey; J. Andrew Bagnell
We present PROCAB, an efficient method for Probabilistically Reasoning from Observed Context-Aware Behavior. It models the context-dependent utilities and underlying reasons that people take different actions. The model generalizes to unseen situations and scales to incorporate rich contextual information. We train our model using the route preferences of 25 taxi drivers demonstrated in over 100,000 miles of collected data, and demonstrate the performance of our model by inferring: (1) decision at next intersection, (2) route to known destination, and (3) destination given partially traveled route.
Keywords: decision modeling, route prediction, vehicle navigation
Accessible contextual information for urban orientation BIBAKFull-Text 332-335
  Jason Stewart; Sara Bauman; Michelle Escobar; Jakob Hilden; Kumud Bihani; Mark W. Newman
We present Talking Points, an urban orientation system based on the idea that an individual's walking journey can be enhanced by providing contextual information about points of interest (POIs) along their route. Our formative research revealed numerous ways to provide serendipitous and task-critical information for both sighted and visually impaired users as they navigate through an urban environment on foot. Based on this, we developed a prototype system comprised of the following: an unobtrusive mobile device to present the user with contextual information; a socially maintained online database containing information about POIs; software that is accessible via both a graphical and a speech user interface; and location "tags" to be detected by the unobtrusive device. This socially maintained urban orientation and contextual information system offers relevant, dynamic, and up-to-date information, a combination which may not otherwise be accessible.
Keywords: accessibility, blind, contextual information system, mobile computing, urban orientation
Enhanced shopping: a dynamic map in a retail store BIBAKFull-Text 336-339
  Alexander Meschtscherjakov; Wolfgang Reitberger; Michael Lankes; Manfred Tscheligi
This article investigates the prototypical implementation of a dynamic map of a retail store and the results of an empirical study in the shopping environment. Due to the distinct characteristics of the context of shopping (e.g. openness to the public, preexisting technologies), this context is particularly fruitful for UbiComp technologies. The prototype consists of a display showing an enhanced store map, which combines the dynamic visualization of customer activity (e.g. hot-spots, sales ranks) with conventional map elements (e.g. product locations, promotions). The results of our three-day in-situ study indicate the relevance and the usefulness of UbiComp technologies for shopping environments.
Keywords: ambient display, dynamic map, field study, retail store, shopping environment, ubiquitous computing

Augmenting everyday life

Spyn: augmenting knitting to support storytelling and reflection BIBAKFull-Text 340-349
  Daniela K. Rosner; Kimiko Ryokai
Ubicomp research has spurred the exploration of more "natural" or "invisible" interfaces that can be seamlessly embedded into their environment. In this paper, we discuss the role such technology can play in augmenting existing creative practice to enhance the sharing of the handcraft process. We present the design and implementation of Spyn, a system for knitters to record, playback, and share information involved in the creation of their hand-knit artifacts. Guided by a formative study of knitting practices, we designed Spyn to capture information while a person knits and allow for the subsequent retrieval of the information using the knit artifact. Spyn uses computer vision techniques in combination with patterns of infrared ink printed on yarn to correlate locations in knit fabric with messages recorded during the knitting process. Rather than seeking to improve the speed or accuracy of the knitter, we designed Spyn to enrich the knitter's craft while preserving the look and feel of the knit artifact.
Keywords: annotation, calm technology, communication, craft, handmade, process, tangible
Picture this!: film assembly using toy gestures BIBAKFull-Text 350-359
  Cati Vaucelle; Hiroshi Ishii
We present Picture This! a new input device embedded in children's toys for video composition. It consists of a new form of interaction for children's capturing of storytelling with physical artifacts. It functions as a video and storytelling performance system in that children craft videos with and about character toys as the system analyzes their gestures and play patterns. Children's favorite props alternate between characters and cameramen in a film. As they play with the toys to act out a story, they conduct film assembly. We position our work as ubiquitous computing that supports children's tangible interaction with digital materials. During user testing, we observed children ages 4 to 10 playing with Picture This!. We assess to what extent gesture interaction with objects for video editing allows children to explore visual perspectives in storytelling. A new genre of Gesture Object Interfaces as exemplified by Picture This relies on the analysis of gestures coupled with objects to represent bits.
Keywords: children, gesture object interfaces, play, storytelling, video
Bookisheet: bendable device for browsing content using the metaphor of leafing through the pages BIBAKFull-Text 360-369
  Jun-ichiro Watanabe; Arito Mochizuki; Youichi Horry
We have developed an interface for browsing content that uses the metaphor of turning the pages of a book. Using our "Bookisheet" interface, which consists of two thin plastic sheets and bend sensors, a user can easily scroll digital content such as photos by bending one side of the sheet or the other. This action provides the tangible and pleasant sense of turning pages in a book. Bookisheet can be used not only as an interface for conventional information terminals but also as one for flexible displays.
Keywords: book metaphor, content browsing, flexible display, navigation, tangible user interface
Living with tableau machine: a longitudinal investigation of a curious domestic intelligence BIBAKFull-Text 370-379
  Zachary Pousman; Mario Romero; Adam Smith; Michael Mateas
We present a longitudinal investigation of Tableau Machine, an intelligent entity that interprets and reflects the lives of occupants in the home. We created Tableau Machine (TM) to explore the parts of home life that are unrelated to accomplishing tasks. Task support for "smart homes" has inspired many researchers in the community. We consider design for experience, an orthogonal dimension to task-centric home life. TM produces abstract visualizations on a large LCD every few minutes, driven by a set of four overhead cameras that capture a sense of the social life of a domestic space. The openness and ambiguity of TM allow for a cycle of co-interpretation with householders. We report on three longitudinal deployments of TM for a period of six weeks. Participant families engaged with TM at the outset to understand how their behaviors were influencing the machine, and, while TM remained puzzling, householders interacted richly with TM and its images. We extract some key design implications for an experience-focused smart home.
Keywords: activity characterization, ambient intelligence, casual information visualization, evaluation techniques, information visualization, interactive art, sensors
Who will be the customer?: a social robot that anticipates people's behavior from their trajectories BIBAKFull-Text 380-389
  Takayuki Kanda; Dylan F. Glas; Masahiro Shiomi; Hiroshi Ishiguro; Norihiro Hagita
For a robot providing services to people in a public space such as a train station or a shopping mall, it is important to distinguish potential customers, such as window-shoppers, from other people, such as busy commuters. In this paper, we present a series of techniques for anticipating people's behavior in a public space, mainly based on the analysis of accumulated trajectories, and we demonstrate the use of these techniques in a social robot. We placed a ubiquitous sensor network consisting of six laser range finders in a shopping arcade. The system tracks people's positions as well as their local behaviors such as fast walking, idle walking, or stopping. We accumulated people's trajectories for a week, applying a clustering technique to the accumulated trajectories to extract information about the use of space and people's typical global behaviors. This information enables the robot to target its services to people who are walking idly or stopping. The robot anticipates both the areas in which people are likely to perform these behaviors, and also the probable local behaviors of individuals a few seconds in the future. In a field experiment we demonstrate that this system enables the robot to serve people efficiently.
Keywords: behavior anticipation, human-robot interaction