Publications

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2008

Vital Sign Estimation from Passive Thermal Video

Publication Details
  • IEEE Computer Society Conference on Computer Vision and Pattern Recognition
  • Jun 24, 2008

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Conventional wired detection of vital signs limits the use of these important physiological parameters by many applications, such as airport health screening, elder care, and workplace preventive care. In this paper, we explore contact-free heart rate and respiratory rate detection through measuring infrared light modulation emitted near superficial blood vessels or a nasal area respectively. To deal with complications caused by subjects' movements, facial expressions, and partial occlusions of the skin, we propose a novel algorithm based on contour segmentation and tracking, clustering of informative pixels, and dominant frequency component estimation. The proposed method achieves robust subject regions-of-interest alignment and motion compensation in infrared video with low SNR. It relaxes some strong assumptions used in previous work and substantially improves on previously reported performance. Preliminary experiments on heart rate estimation for 20 subjects and respiratory rate estimation for 8 subjects exhibit promising results.

1st International Workshop on Collaborative Information Retrieval

Publication Details
  • JCDL 2008
  • Jun 20, 2008

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Explicit support for collaboration is becoming increasingly important for certain kinds of collection-building activities in digital libraries. In the last few years, several research groups have also pursued various issues related to collaboration during search [4][5][6]. We can represent collaboration in search on two dimensions - synchrony and intent. Asynchronous collaboration means that people are not working on the same problem simultaneously; implicit collaboration occurs when the system uses information from others' use of the system to inform new searches, but does not guarantee consistency of search goals. In this workshop, we are concerned with the top-left quadrant of Figure 1 that represents small groups of people working toward a common goal at the same time. These synchronous, explicit collaborations could occur amongst remotely situated users, each with their own computers, or amongst a co-located group sharing devices; these spatial configurations add yet another dimension to be considered when designing collaborative search systems.
Publication Details
  • 1st International Workshop on Collaborative Information Retrieval. JCDL 2008.
  • Jun 20, 2008

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People can help other people find information in networked information seeking environments. Recently, many such systems and algorithms have proliferated in industry and in academia. Unfortunately, it is difficult to compare the systems in meaningful ways because they often define collaboration in different ways. In this paper, we propose a model of possible kinds of collaboration, and illustrate it with examples from literature. The model contains four dimensions: intent, concurrency, depth and location. This model can be used to classify existing systems and to suggest possible opportunities for design in this space.

Simple and Effective Defense Against Evil Twin Access Points

Publication Details
  • Proceedings ACM WiSec, pp. 220-235, 2008
  • Mar 31, 2008

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Wireless networking is becoming widespread in many public places such as cafes. Unsuspecting users may become victims of attacks based on ``evil twin'' access points. These rogue access points are operated by criminals in an attempt to launch man-in-the-middle attacks. We present a simple protection mechanism against binding to an evil twin. The mechanism leverages short authentication string protocols for the exchange of cryptographic keys. The short string verification is performed by encoding the short strings as a sequence of colors, rendered sequentially by the user's device and by the designated access point of the cafe. The access point must have a light capable of showing two colors and must be mounted prominently in a position where users can have confidence in its authenticity. We conducted a usability study with patrons in several cafes and participants found our protection mechanism very usable.

FXPAL Interactive Search Experiments for TRECVID 2007

Publication Details
  • TRECVid 2007
  • Mar 1, 2008

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In 2007 FXPAL submitted results for two tasks: rushes summarization and interactive search. The rushes summarization task has been described at the ACM Multimedia workshop. Interested readers are referred to that publication for details. We describe our interactive search experiments in this notebook paper.

Exiting the Cleanroom: On Ecological Validity and Ubiquitous Computing

Publication Details
  • Human-Computer Interaction Journal
  • Feb 15, 2008

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Over the past decade and a half, corporations and academies have invested considerable time and money in the realization of ubiquitous computing. Yet design approaches that yield ecologically valid understandings of ubiquitous computing systems, which can help designers make design decisions based on how systems perform in the context of actual experience, remain rare. The central question underlying this paper is: what barriers stand in the way of real-world, ecologically valid design for ubicomp? Using a literature survey and interviews with 28 developers, we illustrate how issues of sensing and scale cause ubicomp systems to resist iteration, prototype creation, and ecologically valid evaluation. In particular, we found that developers have difficulty creating prototypes that are both robust enough for realistic use and able to handle ambiguity and error, and that they struggle to gather useful data from evaluations either because critical events occur infrequently, because the level of use necessary to evaluate the system is difficult to maintain, or because the evaluation itself interferes with use of the system. We outline pitfalls for developers to avoid as well as practical solutions, and we draw on our results to outline research challenges for the future. Crucially, we do not argue for particular processes, sets of metrics, or intended outcomes but rather focus on prototyping tools and evaluation methods that support realistic use in realistic settings that can be selected according to the needs and goals of a particular developer or researcher.