We have developed an interactive video search system that allows the searcher to rapidly assess query results and easily pivot off those results to form new queries. The system is intended to maximize the use of the discriminative power of the human searcher. The typical video search scenario we consider has a single searcher with the ability to search with text and content-based queries. In this paper, we evaluate a new collaborative modification of our search system. Using our system, two or more users with a common information need search together, simultaneously. The collaborative system provides tools, user interfaces and, most importantly, algorithmically-mediated retrieval to focus, enhance and augment the team's search and communication activities. In our evaluations, algorithmic mediation improved the collaborative performance of both retrieval (allowing a team of searchers to find relevant information more efficiently and effectively), and exploration (allowing the searchers to find relevant information that cannot be found while working individually). We present analysis and conclusions from comparative evaluations of the search system.

As the use of rich media in mobile devices and smart environments becomes more sophisticated, so must the design of the everyday objects used as controllers and interfaces. Many new interfaces simply tack electronic systems onto existing forms. However, an original physical design for a smart artefact, that integrates new systems as part of the form of the device, can enhance the end-use experience. The Convertible Podium is an experiment in the design of a smart artefact with complex integrated systems for the use of rich media in meeting rooms. It combines the highly designed look and feel of a modern lectern with systems that allow it to serve as a central control station for rich media manipulation. The interface emphasizes tangibility and ease of use in controlling multiple screens, multiple media sources (including mobile devices) and multiple distribution channels, and managing both data and personal representation in remote telepresence.

We describe Cerchiamo, a collaborative exploratory search system that allows teams of searchers to explore document collections synchronously. Working with Cerchiamo, team members use independent interfaces to run queries, browse results, and make relevance judgments. The system mediates the team members' search activity by passing and reordering search results and suggested query terms based on the teams' actions. The combination of synchronous influence with independent interaction allows team members to be more effective and efficient in performing search tasks.

It is increasingly common to find Multiple Display Environments (MDEs) in a variety of settings, including the workplace, the classroom, and perhaps soon, the home. While some technical challenges exist even in single-user MDEs, collaborative use of MDEs offers a rich set of opportunities for research and development. In this workshop, we will bring together experts in designing, developing, building and evaluating MDEs to improve our collective understanding of design guidelines, relevant real-world activities, evaluation methods and metrics, and opportunities for remote as well as collocated collaboration. We intend to create not only a broader understanding of this growing field, but also to foster a community of researchers interested in bringing these environments from the laboratory to the real world. In this workshop, we intended to explore the following research themes:

• Elicitation and process of distilling design guidelines for MDE systems and interfaces.
• Investigation and classification of activities suited for MDEs.
• Exploration and assessment of how existing groupware theories apply to collaboration in MDEs.
• Evaluation techniques and metrics for assessing effectiveness of prototype MDE systems and interfaces.
• Exploration of MDE use beyond strictly collocated collaboration.

In this workshop we will explore how the experience of smart conference rooms can be broadened to include different contexts and media such as context-aware mobile systems, personal and professional videoconferencing, virtual worlds, and social software. How should the technologies behind conference room systems reflect the rapidly changing expectations around personal devices and social online spaces like Facebook, Twitter, and Second Life? What kinds of systems are needed to support meetings in technologically complex environments? How can a mashup of conference room spaces and technologies account for differing social and cultural practices around meetings? What requirements are imposed by security and privacy issues in public and semi-public spaces?

Reading online poses a number of technological challenges. Advances in technology such as touch screens, light-weight high-power computers, and bi-stable displays have periodically renewed interest in online reading over the last twenty years, only to see that interest decline to a small early-adopter community. The recent release of the Kindle by Amazon is another attempt to create an online reading device. Has publicity surrounding Kindle and other such devices has reached critical mass to allow them to penetrate the consumer market successfully, or will we see a decline in interest over the next couple of years echoing the lifecycle of Softbook™ and Rocket eBook™ devices that preceded them? I argue that the true value of online reading lies in supporting activities beyond reading per se: activities such as annotation, reading and comparing multiple documents, transitions between reading, writing and retrieval, etc. Whether the current hardware will be successful in the long term may depend on its abilities to address the reading needs of knowledge workers, not just leisure readers.

Audio monitoring has many applications but also raises pri- vacy concerns. In an attempt to help alleviate these con- cerns, we have developed a method for reducing the intelli- gibility of speech while preserving intonation and the ability to recognize most environmental sounds. The method is based on identifying vocalic regions and replacing the vocal tract transfer function of these regions with the transfer function from prerecorded vowels, where the identity of the replacement vowel is independent of the identity of the spoken syllable. The audio signal is then re-synthesized using the original pitch and energy, but with the modied vocal tract transfer function. We performed an intelligibility study which showed that environmental sounds remained recognizable but speech intelligibility can be dramatically reduced to a 7% word recognition rate.

We present an automatic zooming technique that leverages content analysis for viewing a document page on a small display such as a mobile phone or PDA. The page can come from a scanned document (bitmap image) or an electronic document (text and graphics data plus metadata). The page with text and graphics is segmented into regions. For each region, a scale-distortion function is constructed based on image analysis of the signal distortion that occurs at different scales. During interactive viewing of the document, as the user navigates by moving the viewport around the page, the zoom factor is automatically adjusted by optimizing the scale-distortion functions of the regions visible in the viewport.

In this video demo, we present mTable, a multimedia tabletop system for browsing photo and video collections. We have developed a set of applications for visualizing and exploring photos, a board game for labeling photos, and a 3D cityscape metaphor for browsing videos. The system is suitable for use in a living room or office lounge, and can support multiple displays by visualizing the collections on the tabletop and showing full-size images and videos on another flat panel display in the room.

PicNTell is a new technique for generating compelling screencasts where users can quickly record desktop activities and generate videos that are embeddable on popular video sharing distributions such as YouTube®. While standard video editing and screen capture tools are useful for some editing tasks, they have two main drawbacks: (1) they require users to import and organize media in a separate interface, and (2) they do not support natural (or camcorder-like) screen recording, and instead usually require the user to define a specific region or window to record. In this paper we review current screen recording use, and present the PicNTell system, pilot studies, and a new six degree-of-freedom tracker we are developing in response to our findings.

This demo introduces a tool for accessing an e-document by capturing one or more images of a real object or document hardcopy. This tool is useful when a file name or location of the file is unknown or unclear. It can save field workers and office workers from remembering/exploring numerous directories and file names. Frequently, it can convert tedious keyboard typing in a search box to a simple camera click. Additionally, when a remote collaborator cannot clearly see an object or a document hardcopy through remote collaboration cameras, this tool can be used to automatically retrieve and send the original e-document to a remote screen or printer.

We introduce the Ranked Feature Fusion framework for information retrieval system design. Typical information retrieval formalisms such as the vector space model, the best-match model and the language model first combine features (such as term frequency and document length) into a unified representation, and then use the representation to rank documents. We take the opposite approach: Documents are first ranked by the relevance of a single feature value and are assigned scores based on their relative ordering within the collection. A separate ranked list is created for every feature value and these lists are then fused to produce a final document scoring. This new ``rank then combine'' approach is extensively evaluated and is shown to be as effective as traditional ``combine then rank'' approaches. The model is easy to understand and contains fewer parameters than other approaches. Finally, the model is easy to extend (integration of new features is trivial) and modify. This advantage includes but is not limited to relevance feedback and distribution flattening.

Retail establishments want to know about traffic flow and patterns of activity in order to better arrange and staff their business. A large number of fixed video cameras are commonly installed at these locations. While they can be used to observe activity in the retail environment, assigning personnel to this is too time consuming to be valuable for retail analysis. We have developed video processing and visualization techniques that generate presentations appropriate for examining traffic flow and changes in activity at different times of the day. Taking the results of video tracking software as input, our system aggregates activity in different regions of the area being analyzed, determines the average speed of moving objects in the region, and segments time based on significant changes in the quantity and/or location of activity. Visualizations present the results as heat maps to show activity and object counts and average velocities overlaid on the map of the space.

This video shows the Virtual Physics Circus, a kind of playground for experimenting with simple physical models. The system makes it easy to create worlds with common physical objects such as swings, vehicles, ramps, and walls, and interactively play with those worlds. The system can be used as a creative art medium as well as to gain understanding and intuition about physical systems. The system can be controlled by a number of UI devices such as mouse, keyboard, joystick, and tags which are tracked in 6 degrees of freedom.

In this paper we describe methods for video summarization in the context of the TRECVID 2008 BBC Rushes Summarization task. Color, motion, and audio features are used to segment, filter, and cluster the video. We experiment with varying the segment similarity measure to improve the joint clustering of segments with and without camera motion. Compared to our previous effort for TRECVID 2007 we have reduced the complexity of the summarization process as well as the visual complexity of the summaries themselves. We find our objective (inclusion) performance to be competitive with systems exhibiting similar subjective performance.

The iPhone takes a fresh approach at defining the user interface for mobile devices, which invites further innovation for new generations of touch enabled mobile devices. At the same time, some of its interaction designs provide challenges. For example, swiping gestures can be used anywhere on the screen of an iPhone for navigation, no scroll bars are used. This makes navigation remarkably seamless and easy, at the expense of selection tasks that would also be supported naturally by the same gestures. In this demo, we show techniques that enable both activities simultaneously with minimal interference. We also demonstrate other user interface designs that are driven by the features and and a desire to overcome the limits of small displays for iPhone-type devices. This includes diagonal scrolling as a means to maximize line width and font size for mobile reading, and a graphical authentication method.

This workshop is the fourth in a series of UbiComp workshops on smart environment technologies and applications for the workplace. It offers a unique window into the state of the art through the participation of a range of researchers, designers and builders who exchange both basic research and real-world case experiences; and invites participants to share ideas about them. This year we focus on understanding appropriate design processes and creating valid evaluation metrics for smart environments (a recurrent request from previous workshop participants). What design processes allow integration of new ubicomp-style systems with existing technologies in a room that is in daily use? What evaluation methods and metrics give us an accurate picture, and how can that information best be applied in an iterative design process?

While recent timed-release encryption (TRE) schemes are implicitly supported by a certificateless encryption (CLE) mechanism, the security models of CLE and TRE differ and there is no generic trans- formation from a CLE to a TRE. This paper gives a generalized model for CLE that fulfills the requirements of TRE. This model is secure against adversaries with adaptive trapdoor extraction capabilities for arbitrary identifiers, decryption capabilities for arbitrary public keys, and partial decryption capabilities. It also supports hierarchical identifiers. We pro- pose a concrete scheme under our generalized model and prove it secure without random oracles, yielding the first strongly-secure SMCLE and the first TRE in the standard model. In addition, our technique of partial decryption is different from the previous approach.

Mobile media applications need to balance user and group goals, attentional constraints, and limited screen real estate. In this paper, we describe the development and testing of two application sketches designed to explore these tradeoffs. The first is retrospective and time- based and the second is prospective and space-based. We found that attentional demands dominate and mobile media applications should therefore be lightweight and hands-free as much as possible.

While researchers have been exploring automatic presentation capture since the 1990's, real world adoption has been limited. Our research focuses on simplifying presentation capture and retrieval to reduce adoption barriers. ProjectorBox is our attempt to create a smart appliance that seamlessly captures, indexes, and archives presentation media, with streamlined user interfaces for searching, skimming, and sharing content. In this paper we describe the design of ProjectorBox and compare its use across corporate and educational settings. While our evaluation confirms the usability and utility of our approach across settings, it also highlights differences in usage and user needs, suggesting enhancements for both markets. We describe new features we have implemented to address corporate needs for enhanced privacy and security, and new user interfaces for content discovery.

We describe a new approach to information retrieval: algorithmic mediation for intentional, synchronous collabo- rative exploratory search. Using our system, two or more users with a common information need search together, simultaneously. The collaborative system provides tools, user interfaces and, most importantly, algorithmically-mediated retrieval to focus, enhance and augment the team's search and communication activities. Collaborative search outperformed post hoc merging of similarly instrumented single user runs. Algorithmic mediation improved both collaborative search (allowing a team of searchers to nd relevant in- formation more efficiently and effectively), and exploratory search (allowing the searchers to find relevant information that cannot be found while working individually).

We have developed an interactive video search system that allows the searcher to rapidly assess query results and easily pivot on those results to form new queries. The system is intended to maximize the use of the discriminative power of the human searcher. This is accomplished by providing a hierarchical segmentation, streamlined interface, and redundant visual cues throughout. The typical search scenario includes a single searcher with the ability to search with text and content-based queries. In this paper, we evaluate new variations on our basic search system. In particular we test the system using only visual content-based search capabilities, and using paired searchers in a realtime collaboration. We present analysis and conclusions from these experiments.

This paper describes FXPAL's collaborative, exploratory interactive video search application. We introduce a new approach to information retrieval: algorithmic mediation in support of intentional, synchronous collaborative exploratory search. Using our system, two or more users with a common information need search together, simultaneously. The collaborative system provides tools, user interfaces and, most importantly, algorithmically-mediated retrieval to focus, enhance and augment the team's search and communication activities.

Collaboration in information seeking, while common in practice, is just being recognized as an important research area. Several studies have documented various collaboration strategies that people have adopted (and adapted), and some initial systems have been built. This field is in its infancy, however. We need to understand which real-world tasks are best suited for collaborative work. We need to extend models of information seeking to accommodate explicit and implicit collaboration. We need to invent a suite of algorithms to mediate search activities. We need to devise evaluation metrics that take into account multiple people's contributions to search.

Current approaches to pose estimation and tracking can be classified into two categories: generative and discriminative. While generative approaches can accurately determine human pose from image observations, they are computationally intractable due to search in the high dimensional human pose space. On the other hand, discriminative approaches do not generalize well, but are computationally efficient. We present a hybrid model that combines the strengths of the two in an integrated learning and inference framework. We extend the Gaussian process latent variable model (GPLVM) to include an embedding from observation space (the space of image features) to the latent space. GPLVM is a generative model, but the inclusion of this mapping provides a discriminative component, making the model observation driven. Observation Driven GPLVM (OD-GPLVM) not only provides a faster inference approach, but also more accurate estimates (compared to GPLVM) in cases where dynamics are not sufficient for the initialization of search in the latent space. We also extend OD-GPLVM to learn and estimate poses from parameterized actions/gestures. Parameterized gestures are actions which exhibit large systematic variation in joint angle space for different instances due to difference in contextual variables. For example, the joint angles in a forehand tennis shot are function of the height of the ball (Figure 2). We learn these systematic variations as a function of the contextual variables. We then present an approach to use information from scene/object to provide context for human pose estimation for such parameterized actions.