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Proceedings of Pervasive 2004: International Conference on Pervasive Computing

Fullname:Pervasive 2004: Pervasive Computing, Second International Conference
Editors:Alois Ferscha; Friedemann Mattern
Location:Vienna, Austria
Dates:2004-Apr-21 to 2004-Apr-23
Series:Lecture Notes in Computer Science 3001 Springer 2004
Standard No:ISBN 3-540-21835-1; hcibib: Pervasive04
Links:Online Proceedings
  1. Activity Recognition
  2. Context Computing
  3. Near Body Interfaces
  4. Software
  5. Sensors
  6. Security
  7. Architectures and Systems
  8. Algorithms
  9. New Interfaces

Activity Recognition

Activity Recognition from User-Annotated Acceleration Data BIBAFull-Text 1-17
  Ling Bao; Stephen S. Intille
In this work, algorithms are developed and evaluated to detect physical activities from data acquired using five small biaxial accelerometers worn simultaneously on different parts of the body. Acceleration data was collected from 20 subjects without researcher supervision or observation. Subjects were asked to perform a sequence of everyday tasks but not told specifically where or how to do them. Mean, energy, frequency-domain entropy, and correlation of acceleration data was calculated and several classifiers using these features were tested. Decision tree classifiers showed the best performance recognizing everyday activities with an overall accuracy rate of 84%. The results show that although some activities are recognized well with subject-independent training data, others appear to require subject-specific training data. The results suggest that multiple accelerometers aid in recognition because conjunctions in acceleration feature values can effectively discriminate many activities. With just two biaxial accelerometers -- thigh and wrist -- the recognition performance dropped only slightly. This is the first work to investigate performance of recognition algorithms with multiple, wire-free accelerometers on 20 activities using datasets annotated by the subjects themselves.
Recognizing Workshop Activity Using Body Worn Microphones and Accelerometers BIBAFull-Text 18-32
  Paul Lukowicz; Jamie A. Ward; Holger Junker; Mathias Stäger; Gerhard Tröster; Amin Atrash; Thad Starner
The paper presents a technique to automatically track the progress of maintenance or assembly tasks using body worn sensors. The technique is based on a novel way of combining data from accelerometers with simple frequency matching sound classification. This includes the intensity analysis of signals from microphones at different body locations to correlate environmental sounds with user activity.
   To evaluate our method we apply it to activities in a wood shop. On a simulated assembly task our system can successfully segment and identify most shop activities in a continuous data stream with zero false positives and 84.4% accuracy.
"Are You with Me?" -- Using Accelerometers to Determine If Two Devices Are Carried by the Same Person BIBAFull-Text 33-50
  Jonathan Lester; Blake Hannaford; Gaetano Borriello
As the proliferation of pervasive and ubiquitous computing devices continues, users will carry more devices. Without the ability for these devices to unobtrusively interact with one another, the user's attention will be spent on coordinating, rather than using, these devices. We present a method to determine if two devices are carried by the same person, by analyzing walking data recorded by low-cost MEMS accelerometers using the coherence function, a measure of linear correlation in the frequency domain. We also show that these low-cost sensors perform similarly to more expensive accelerometers for the frequency range of human motion, 0 to 10Hz. We also present results from a large test group illustrating the algorithm's robustness and its ability to withstand real world time delays, crucial for wireless technologies like Bluetooth and 802.11. We present results that show that our technique is 100% accurate using a sliding window of 8 seconds of data when the devices are carried in the same location on the body, is tolerant to inter-device communication latencies, and requires little communication bandwidth. In addition we present results for when devices are carried on different parts of the body.

Context Computing

Context Cube: Flexible and Effective Manipulation of Sensed Context Data BIBAFull-Text 51-68
  Lonnie D. Harvel; Ling Liu; Gregory D. Abowd; Yu-Xi Lim; Chris Scheibe; Chris Chatham
In an effort to support the development of context-aware applications that use archived sensor data, we introduce the concept of the Context Cube based on techniques of data warehousing and data mining. Our implementation of the Context Cube provides a system that supports a multi-dimensional model of context data and with tools for accessing, interpreting and aggregating that data by using concept relationships defined within the real context of the application. We define the Context Cube information model, demonstrate functional applications that we have developed with the system, and explore possible applications that may be developed more easily using our tool.
A Context-Aware Communication Platform for Smart Objects BIBAFull-Text 69-86
  Frank Siegemund
When smart objects participate in context-aware applications, changes in their real-world environment can have a significant impact on underlying networking structures. This paper presents a communication platform for smart objects that takes an object's current real-world context into account and adapts networking structures accordingly. The platform provides (1) mechanisms for specifying and implementing context-aware communication services, (2) a tuplespace-based communication abstraction for inter-object collaboration, and (3) support for linking communication and context-recognition layers. For specifying context-aware communication services, a high-level description language, called SICL, and a compiler that generates corresponding code for smart objects were realized. The tuplespace-based infrastructure layer for inter-object collaboration hides low-level communication issues from higher layers and facilitates collaborative context recognition between cooperating objects. The paper also presents examples of context-aware communication services and evaluates the platform on the basis of a concrete implementation on an embedded device platform.
Siren: Context-aware Computing for Firefighting BIBAFull-Text 87-105
  Xiaodong Jiang; Nicholas Y. Chen; Jason I. Hong; Kevin Wang; Leila Takayama; James A. Landay
Based on an extensive field study of current firefighting practices, we have developed a system called Siren to support tacit communication between firefighters with multiple levels of redundancy in both communication and user alerts. Siren provides a foundation for gathering, integrating, and distributing contextual data, such as location and temperature. It also simplifies the development of firefighting applications using a peer-to-peer network of embedded devices through a uniform programming interface based on the information space abstraction. As a proof of concept, we have developed a prototype context-aware messaging application in the firefighting domain. We have evaluated this application with firefighters and they have found it to be useful for improving many aspects of their current work practices.

Near Body Interfaces

Spectacle-Based Design of Wearable See-Through Display for Accommodation-Free Viewing BIBAFull-Text 106-123
  Marc von Waldkirch; Paul Lukowicz; Gerhard Tröster
This paper presents the design and the evaluation of a novel wearable see-through display which provides imaging being nearly independent from the eye's accommodation. This means, that the overlaid display data are perceived to be in-focus independent of the distance the eye is focusing at, making the see-through mode much more convenient in use. The display is based on the direct projection of a miniature LCD onto the user's retina in combination with the use of partially coherent light to further improve the display's defocusing properties.
   The paper discusses the display concept and presents various experimental results for verification. Finally, a compact and lightweight design for an unobtrusive integration into normal spectacles is proposed.
A Compact Battery-Less Information Terminal for Real World Interaction BIBAFull-Text 124-139
  Takuichi Nishimura; Hideo Itoh; Yoshiyuki Nakamura; Yoshinobu Yamamoto; Hideyuki Nakashima
A ubiquitous computing environment is intended to support users in their search for necessary information and services in a situation-dependent form. This paper proposes a location-based information support system using a Compact Battery-less Information Terminal (CoBIT) to support users interactively. A CoBIT can communicate with the environmental system and with the user using only energy supplied from the environmental system and the user. The environmental system has functions to detect the terminal position and direction to realize situational support. This paper newly shows detailed characteristics of information download and upload using the CoBIT system. And it also describes various types of CoBITs and their usage in museums and event shows.


INCA: A Software Infrastructure to Facilitate the Construction and Evolution of Ubiquitous Capture & Access Applications BIBAFull-Text 140-157
  Khai N. Truong; Gregory D. Abowd
People's daily lives provide them with memories and records that they often want to review later. They must expend time and effort to record these experiences manually for future retrieval. To address this issue, applications that automatically capture details of a live experience and provide future access to that experience have become an increasingly common theme of research in ubiquitous computing. In this paper, we present our experience building a number of capture and access applications, sharing insights on the successes and difficulties we encountered. These lessons inform the design of the INCA toolkit (Infrastructure for Capture and Access), which supports the construction of applications in this class. We will demonstrate how INCA facilitates the rapid prototyping and simplified evolution of increasingly complex capture and access applications.


Activity Recognition in the Home Using Simple and Ubiquitous Sensors BIBAFull-Text 158-175
  Emmanuel Munguia Tapia; Stephen S. Intille; Kent Larson
In this work, a system for recognizing activities in the home setting using a set of small and simple state-change sensors is introduced. The sensors are designed to be "tape on and forget" devices that can be quickly and ubiquitously installed in home environments. The proposed sensing system presents an alternative to sensors that are sometimes perceived as invasive, such as cameras and microphones. Unlike prior work, the system has been deployed in multiple residential environments with non-researcher occupants. Preliminary results on a small dataset show that it is possible to recognize activities of interest to medical professionals such as toileting, bathing, and grooming with detection accuracies ranging from 25% to 89% depending on the evaluation criteria used.
Automatic Calibration of Body Worn Acceleration Sensors BIBAFull-Text 176-181
  Paul Lukowicz; Holger Junker; Gerhard Tröster
The paper presents a scheme for automatic calibration of body worn acceleration sensors which does not require any user interaction and any knowledge about the position and orientation of the sensors on the body. We describe the theoretical principle behind the method, discuss the main practical implementation concerns, and present experimental validation results.
Reject-Optional LVQ-Based Two-Level Classifier to Improve Reliability in Footstep Identification BIBAFull-Text 182-187
  Jaakko Suutala; Susanna Pirttikangas; Jukka Riekki; Juha Röning
This paper reports experiments of recognizing walkers based on measurements with a pressure-sensitive EMFi-floor. Identification is based on a two-level classifier system. The first level performs Learning Vector Quantization (LVQ) with a reject option to identify or to reject a single footstep. The second level classifies or rejects a sequence of three consecutive identified footsteps based on the knowledge from the first level. The system was able to reduce classification error compared to a single footstep classifier without a reject option. The results show a 90% overall success rate with a 20% rejection rate, identifying eleven walkers, which can be considered very reliable.
Issues with RFID Usage in Ubiquitous Computing Applications BIBAFull-Text 188-193
  Christian Floerkemeier; Matthias Lampe
Radio Frequency Identification (RFID) has recently received a lot of attention as an augmentation technology in the ubiquitous computing domain. In this paper we present various sources of error in passive RFID systems, which can make the reliable operation of RFID augmented applications a challenge. To illustrate these sources of error, we equipped playing cards with RFID tags and measured the performance of the RFID system during the different stages of a typical card game. The paper also shows how appropriate system design can help to deal with the imperfections associated with RFID.


A Fault-Tolerant Key-Distribution Scheme for Securing Wireless Ad Hoc Networks BIBAFull-Text 194-212
  Arno Wacker; Timo Heiber; Holger Cermann; Pedro José Marrón
We propose a novel solution for securing wireless ad-hoc networks. Our goal is to provide secure key exchange in the presence of device failures and denial-of-service attacks. The proposed solution relies solely on symmetric cryptography and therefore is applicable for highly resource-limited devices. In order to avoid a single point of trust, no master device or base station is used. We achieve this by enhancing our previously published approach with redundancy and algorithms for recovery on device failures.
ProxNet: Secure Dynamic Wireless Connection by Proximity Sensing BIBAFull-Text 213-218
  Jun Rekimoto; Takashi Miyaki; Michimune Kohno
This paper describes a method for establishing ad hoc and infrastructure-mode wireless network connections based on physical proximity. Users can easily establish secure wireless connections between two digital devices by putting them in close proximity to each other and pressing the connection button. The devices "identify" each other by measuring each other's signal strength. We designed a set of protocols to support secure connections between digital devices by using a proximity communication mode to exchange session keys. We also introduce a "dummy point" that is analogous to a wireless access point but handles proximity-mode communication. The dummy point represents physical locations of digital devices and supports context-sensitive network communications.
Tackling Security and Privacy Issues in Radio Frequency Identification Devices BIBAFull-Text 219-224
  Dirk Henrici; Paul Müller
This paper introduces shortly into the security and privacy issues of RFID systems and presents a simple approach to greatly enhance location privacy by changing traceable identifiers securely on every read attempt. The scheme gets by with only a single, unreliable message exchange. By employing one-way hash functions the scheme is safe from many security threats. It is intended for use in item identification but is useful in other applications as well.

Architectures and Systems

Towards Wearable Autonomous Microsystems BIBAFull-Text 225-237
  Nagendra Bhargava Bharatula; Stijn Ossevoort; Mathias Stäger; Gerhard Tröster
This paper presents our work towards a wearable autonomous microsystem for context recognition. The design process needs to take into account the properties of a wearable environment in terms of sensor placement for data extraction, energy harvesting, comfort and easy integration into clothes and accessories. We suggest to encapsulate the system in an embroidery or a button. The study of a microsystem consisting of a light sensor, a microphone, an accelerometer, a microprocessor and a RF transceiver shows that it is feasible to integrate such a system in a button-like form of 12mm diameter and 4mm thickness. We discuss packaging and assembly aspects of such a system. Additionally, we argue that a solar cell on top of the button -- together with a lithium polymer battery as energy storage -- is capable to power the system even for a user who works predominantly indoors.
Ubiquitous Chip: A Rule-Based I/O Control Device for Ubiquitous Computing BIBAFull-Text 238-253
  Tsutomu Terada; Masahiko Tsukamoto; Keisuke Hayakawa; Tomoki Yoshihisa; Yasue Kishino; Atsushi Kashitani; Shojiro Nishio
In this paper, we propose a new framework for ubiquitous computing by rule-based, event-driven I/O (input/output) control devices. Our approach is flexible and autonomous because it employs a behavior-description language based on ECA (Event, Condition, Action) rules with simple I/O control functions. We have implemented a prototype ubiquitous device with connectors and several sensors to show the effectiveness of our approach.
eSeal -- A System for Enhanced Electronic Assertion of Authenticity and Integrity BIBAFull-Text 254-268
  Christian Decker; Michael Beigl; Albert Krohn; Philip Robinson; Uwe Kubach
Ensuring authenticity and integrity are important tasks when dealing with goods. While in the past seal wax was used to ensure the integrity, electronic devices are now able to take over this functionality and provide better, more fine grained, more automated and more secure supervision. This paper presents eSeal, a system with a computational device at its core that can be attached to a good, services in the network and a communication protocol. The system is able to control various kinds of integrity settings and to notify authenticated instances about consequent violations of integrity. The system works without infrastructure so that goods can be supervised that are only accessible in certain locations. The paper motivates the eSeal system and its design decisions, lists several types of integrity scenarios, presents the communication protocol and identifies practical conditions for design and implementation. An implementation in a business relevant scenario is presented as a proof of concept.


A Distributed Precision Based Localization Algorithm for Ad-Hoc Networks BIBAFull-Text 269-286
  Leon Evers; Stefan Dulman; Paul J. M. Havinga
In this paper we introduce a new distributed algorithm for location discovery. It can be used in wireless ad-hoc sensor networks that are equipped with means of measuring the distances between the nodes (like the intensity of the received signal strength). The algorithm takes the reliability of measurements into account during calculation of the nodes positions. Simulation results are presented, showing the algorithms performance in relation to its accuracy, communication and calculation costs. The simulation results of our approach yield 2 to 4 times better results in position accuracy than other systems described previously. This level of performance can be reached using only few broadcast messages with small and constant size, for each node in the network.
Adaptive On-Device Location Recognition BIBAFull-Text 287-304
  Kari Laasonen; Mika Raento; Hannu Toivonen
Location-awareness is useful for mobile and pervasive computing. We present a novel adaptive framework for recognizing personally important locations in cellular networks, implementable on a mobile device and usable, e.g., in a presence service. In comparison, most previous work has used service infrastructure for location recognition and the few adaptive frameworks presented have used coordinate-based data. We construct a conceptual framework for the tasks of learning important locations and predicting the next location. We give algorithms for efficient approximation of the ideal concepts, and evaluate them experimentally with real data.
Accommodating Transient Connectivity in Ad Hoc and Mobile Settings BIBAFull-Text 305-322
  Radu Handorean; Christopher D. Gill; Gruia-Catalin Roman
Much of the work on networking and communications is based on the premise that components interact in one of two ways: either they are connected via a stable wired or wireless network, or they make use of persistent storage repositories accessible to the communicating parties. A new generation of networks raises serious questions about the validity of these fundamental assumptions. In mobile ad hoc wireless networks connections are transient and availability of persistent storage is rare. This paper is concerned with achieving communication among mobile devices that may never find themselves in direct or indirect contact with each other at any point in time. A unique feature of our contribution is the idea of exploiting information associated with the motion and availability profiles of the devices making up the ad hoc network. This is the starting point for an investigation into a range of possible solutions whose essential features are controlled by the manner in which motion profiles are acquired and the extent to which such knowledge is available across an ad hoc network.

New Interfaces

Microbiology Tray and Pipette Tracking as a Proactive Tangible User Interface BIBAFull-Text 323-339
  Harlan Hile; Jiwon Kim; Gaetano Borriello
Many work environments can benefit from integrated computing devices to provide information to users, record users' actions, and prompt users about the next steps to take in a procedure. We focus on the cell biology laboratory, where previous work on the Labscape project has provided a framework to organize experiment plans and store data. Currently developed sensor systems allow amount and type of materials used in experiments to be recorded. This paper focuses on providing the last piece: determining where the materials are deposited. Using a camera and projector setup over a lab bench, vision techniques allow a specially marked well tray and pipette to be located in real time with enough precision to determine which well the pipette tip is over. Using the projector, the tray can be augmented with relevant information, such as the next operation to be performed, or the contents of the tray. Without changing the biologist's work practice, it is possible to record the physical interactions and provide easily available status and advice to the user. Preliminary user feedback suggests this system would indeed be a useful addition to the laboratory environment.
Augmenting Collections of Everyday Objects: A Case Study of Clothes Hangers As an Information Display BIBAFull-Text 340-344
  Tara Matthews; Hans-Werner Gellersen; Kristof Van Laerhoven; Anind K. Dey
Though the common conception of human-computer interfaces is one of screens and keyboards, the emergence of ubiquitous computing envisions interfaces that will spread from the desktop into our environments. This gives rise to the development of novel interaction devices and the augmentation of common everyday objects to serve as interfaces between the physical and the virtual. Previous work has provided exemplars of such everyday objects augmented with interactive behaviour. We propose that richer opportunities arise when collections of everyday objects are considered as substrate for interfaces. In an initial case study we have taken clothes hangers as an example and augmented them to collectively function as an information display.
MirrorSpace: Using Proximity as an Interface to Video-Mediated Communication BIBAFull-Text 345-350
  Nicolas Roussel; Helen Evans; Heiko Hansen
Physical proximity to other people is a form of non-verbal communication that we all employ everyday, although we are barely aware of it. Yet, existing systems for video-mediated communication fail to fully take into account these proxemics aspects of communication. In this note, we present MirrorSpace, a video communication system that uses proximity as an interface to provide smooth transitions between peripheral awareness and very close and intimate forms of communication.
SearchLight -- A Lightweight Search Function for Pervasive Environments BIBAFull-Text 351-356
  Andreas Butz; Michael Schneider; Mira Spassova
We present a lightweight search function for physical objects in instrumented environments. Objects are tagged with optical markers which are scanned by a steerable camera and projector unit on the ceiling. The same projector can then highlight the objects when given the corresponding marker ID. The process is very robust regarding calibration, and no 3D model of the environment is needed. We discuss the scenario of finding books in a library or office environment and several extensions currently under development.