Embedded Media Barcode Links, or simply EMBLs, are optimally blended iconic barcode marks, printed on paper documents, that signify the existence of multimedia associated with that part of the document content (Figure 1). EMBLs are used for multimedia retrieval with a camera phone. Users take a picture of an EMBL-signified document patch using a cell phone, and the multimedia associated with the EMBL-signified document location is displayed on the phone. Unlike a traditional barcode which requires an exclusive space, the EMBL construction algorithm acts as an agent to negotiate with a barcode reader for maximum user and document benefits. Because of this negotiation, EMBLs are optimally blended with content and thus have less interference with the original document layout and can be moved closer to a media associated location. Retrieval of media associated with an EMBL is based on the barcode identification of a captured EMBL. Therefore, EMBL retains nearly all barcode identification advantages, such as accuracy, speed, and scalability. Moreover, EMBL takes advantage of users' knowledge of a traditional barcode. Unlike Embedded Media Maker (EMM) which requires underlying document features for marker identification, EMBL has no requirement for the underlying features. This paper will discuss the procedures for EMBL construction and optimization. It will also give experimental results that strongly support the EMBL construction and optimization ideas.

This special issue brings together papers that describe some of the many ways that collaborative information seeking manifests itself. Some papers report on collaborative practices in a range of domains, including medical (Hertzum), legal (Attfield et al.), and online Q&A (Gazan). Others propose and evaluate models of collaborative activity (Evans and Chi; Evans et al.; Wilson and schraefel; Foley and Smeaton), and others describe systems and algorithms that support collaboration in various ways (Boydell and Smyth; Fernandez-Luna et al., Halvey et al., Morris et al.; Shah et al.).

We describe a new approach for algorithmic mediation of a collaborative search process. Unlike most approaches to collaborative IR, we are designing systems that mediate explicitly-defined synchronous collaboration among small groups of searchers with a shared information need. Such functionality is provided by first obtaining different rank-lists based on searchers' queries, fusing these rank-lists, and then splitting the combined list to distribute documents among collaborators according to their roles. For the work reported here, we consider the case of two people collaborating on a search. We assign them roles of Gatherer and Surveyor: the Gatherer is tasked with exploring highly promising information on a given topic, and the Surveyor is tasked with digging further to explore more diverse information. We demonstrate how our technique provides the Gatherer with high-precision results, and the Surveyor with information that is high in entropy.

Traditional interactive information retrieval systems function by creating inverted lists, or term indexes. For every term in the vocabulary, a list is created that contains the documents in which that term occurs and its relative frequency within each document. Retrieval algorithms then use these term frequencies alongside other collection statistics to identify the matching documents for a query. In this paper, we turn the process around: instead of indexing documents, we index query result sets. First, queries are run through a chosen retrieval system. For each query, the resulting document IDs are treated as terms and the score or rank of the document is used as the frequency statistic. An index of documents retrieved by basis queries is created. We call this index a reverted index. Finally, with reverted indexes, standard retrieval algorithms can retrieve the matching queries (as results) for a set of documents (used as queries). These recovered queries can then be used to identify additional documents, or to aid the user in query formulation, selection, and feedback.

TalkMiner is a search engine for lecture webcasts. Lecture videos are processed to recover a set of distinct slide images and OCR is used to generate a list of indexable terms from the slides. On our prototype system, users can search and browse lists of lectures, slides in a specific lecture, and play the lecture video. Over 10,000 lecture videos have been indexed from a variety of sources. A public website now allows users to experiment with the search engine.

NudgeCam is a mobile application that can help users capture more relevant, higher quality media. To guide users to capture media more relevant to a particular project, third-party template creators can show users media that demonstrates relevant content and can tell users what content should be present in each captured media using tags and other meta-data such as location and camera orientation. To encourage higher quality media capture, NudgeCam provides real time feedback based on standard media capture heuristics, including face positioning, pan speed, audio quality, and many others. We describe an implementation of NudgeCam on the Android platform as well as field deployments of the application.

We will exhibit several aspects of a complex mixed reality system that we have built and deployed in a real-world factory setting. In our system, virtual worlds, augmented realities, and mobile applications are all fed from the same infrastructure. In collaboration with TCHO, a chocolate maker in San Francisco, we built a virtual “mirror” world of a real-world chocolate factory and its processes. Sensor data is imported into the multi-user 3D environment from hundreds of sensors on the factory floor. The resulting virtual factory is used for simulation, visualization, and collaboration, using a set of interlinked, real-time layers of information. Another part of our infrastructure is designed to support appropriate industrial uses for mobile devices such as cell phones and tablet computers. We deployed this system at the real-world factory in 2009, and it is now is daily use there. By simultaneously developing mobile, virtual, and web-based display and collaboration environments, we aimed to create an infrastructure that did not skew toward one type of application but that could serve many at once, interchangeably. Through this mixture of mobile, social, mixed and virtual technologies, we hope to create systems for enhanced collaboration in industrial settings between physically remote people and places, such as factories in China with managers in the US.

The design and implementation of a search engine for lecture webcasts is described. A searchable text index is created allowing users to locate material within lecture videos found on a variety of websites such as YouTube and Berkeley webcasts. The index is created from words on the presentation slides appearing in the video along with any associated metadata such as the title and abstract when available. The video is analyzed to identify a set of distinct slide images, to which OCR and lexical processes are applied which in turn generate a list of indexable terms. Several problems were discovered when trying to identify distinct slides in the video stream. For example, picture-in-picture compositing of a speaker and a presentation slide, switching cameras, and slide builds confuse basic frame-differencing algorithms for extracting keyframe slide images. Algorithms are described that improve slide identification. A prototype system was built to test the algorithms and the utility of the search engine. Users can browse lists of lectures, slides in a specific lecture, or play the lecture video. Over 10,000 lecture videos have been indexed from a variety of sources. A public website will be published in mid 2010 that allows users to experiment with the search engine.

An Embedded Media Marker (EMM) is a transparent mark printed on a paper document that signifies the availability of additional media associated with that part of the document. Users take a picture of the EMM using a camera phone, and the media associated with that part of the document is displayed on the phone. Unlike bar codes, EMMs are nearly transparent and thus do not interfere with the document appearance. Retrieval of media associated with an EMM is based on image features of the document within the EMM boundary. Unlike other feature-based retrieval methods, the EMM clearly indicates to the user the existence and type of media associated with the document location. A semi-automatic authoring tool is used to place an EMM at a location in a document, in such a way that it encompasses sufficient identification features with minimal disturbance to the original document. We will demonstrate how to create an EMM-enhanced document, and how the EMM enables access to the associated media on a cell phone.

FACT is an interactive paper system for fine-grained interaction with documents across the boundary between paper and computers. It consists of a small camera-projector unit, a laptop, and ordinary paper documents. With the camera-projector unit pointing to a paper document, the system allows a user to issue pen gestures on the paper document for selecting fine-grained content and applying various digital functions. For example, the user can choose individual words, symbols, figures, and arbitrary regions for keyword search, copy and paste, web search, and remote sharing. FACT thus enables a computer-like user experience on paper. This paper interaction can be integrated with laptop interaction for cross-media manipulations on multiple documents and views. We present the infrastructure, supporting techniques and interaction design, and demonstrate the feasibility via a quantitative experiment. We also propose applications such as document manipulation, map navigation and remote collaboration.

The massive amounts of information that are being collected about each of us will only increase as sensors become ever cheaper and more powerful. Analysis of this wealth of data supports advances in medicine and public health, improved software and services through user pattern analysis, and more efficient economic mechanisms. At the same time, the potential for misuse of such data is significant. A long-term research question is how best to support beneficial uses while inhibiting misuse. One approach is to enable individuals to maintain tighter control of their own data while still supporting the computation of group statistics. Currently, analysts are usually given access to all data in order to compute statistics, and often use a third party service provider to store, or even process, such data. Either the third party has access to all data or the data are encrypted, in which case the third party does no processing. An interesting research question is how to provide mechanisms to support "need to know" security in which an individual has full access to her own data, the third party learns nothing about the data but can nevertheless contribute to the processing, and the analyst learns only the desired statistics. We have explored "need to know" security in connection with MyUnity, a prototype awareness system. MyUnity collects data from a variety of sources and displays summary presence states, such as ``in office'' or ``with visitor,'' computed from the received data. MyUnity was deployed in a small research lab and has been in use by over 30 people for more than a year. To avoid concerns about misuse, the system did not store any data initially. The researchers developing the system were interested, however, in analyzing usage patterns, and users expressed interest in seeing personal trends, activity patterns of coworkers, and long-term data pooled across groups of users, all requiring data to be stored. At the same time, users continued to be concerned about misuse of stored data. We looked at ``need to know'' security for cases in which, at each time step, each member of a group of users has a value (i.e., a presence state) to contribute, and the group would like to provide only an aggregate view of those values to people outside their group. We designed and implemented an efficient protocol that enables each user to encrypt under her own key in such a way that a third party can compute an encryption of a sum across values encrypted under different keys without the need for further interactions with the individuals. The protocol provides means for an analyst to decrypt the encrypted sum. We designed key structures and extensions to provide a family of efficient non-interactive ``need to know'' protocols for time series data in which the analyst learns only the statistics, not the individual data values, and the third party learns nothing about the values.

We propose an Augmented Reality (AR) system that helps users take a picture from a designated pose, such as the position and camera angle of an earlier photo. Repeat photography is frequently used to observe and document changes in an object. Our system uses AR technology to estimate camera poses in real time. When a user takes a photo, the camera pose is saved as a 'view bookmark.' To support a user in taking a repeat photo, two simple graphics are rendered in an AR viewer on the camera's screen to guide the user to this bookmarked view. The system then uses image adjustment techniques to create an image based on the user's repeat photo that is even closer to the original.

We present a method for picture detection in document page images, which can come from scanned or camera images, or rendered from electronic file formats. Our method uses OCR to separate out the text and applies the Normalized Cuts algorithm to cluster the non-text pixels into picture regions. A refinement step uses the captions found in the OCR text to deduce how many pictures are in a picture region, thereby correcting for under- and over-segmentation. A performance evaluation scheme is applied which takes into account the detection quality and fragmentation quality. We benchmark our method against the ABBYY application on page images from conference papers.

Exploratory search is a difficult activity that requires iterative interaction. This iterative process helps the searcher to understand and to refine the information need. It also generates a rich set of data that can be used effectively to reflect on what has been found (and found useful). In this paper, we describe a framework for unifying transitions among various stages of exploratory search, and show how context from one stage can be applied to the next. The framework can be used both to describe existing information-seeking interactions, and as a means of generating novel ones. We illustrate the framework with examples from a session-based exploratory search system prototype that we have built.

Virtual, mobile, and mixed reality systems have diverse uses for data visualization and remote collaboration in industrial settings, especially factories. We report our experiences in designing complex mixed-reality collaboration, control, and display systems for a real-world factory, for delivering real-time factory information to multiple users. In collaboration with (blank for review), a chocolate maker in San Francisco, our research group is building a virtual “mirror” world of a real-world chocolate factory and its processes. Real-world sensor data (such as temperature and machine state) is imported into the 3D environment from hundreds of sensors on the factory floor. Multi-camera imagery from the factory is also available in the multi-user 3D factory environment. The resulting "virtual factory" is designed for simulation, visualization, and collaboration, using a set of interlinked, real-time 3D and 2D layers of information about the factory and its processes. We are also looking at appropriate industrial uses for mobile devices such as cell phones and tablet computers, and how they intersect with virtual worlds and mixed realities. For example, an experimental iPhone web app provides mobile laboratory monitoring and control. The app allows a real-time view into the lab via steerable camera and remote control of lab machines. The mobile system is integrated with the database underlying the virtual factory world. These systems were deployed at the real-world factory and lab in 2009, and are now in beta development. Through this mashup of mobile, social, mixed and virtual technologies, we hope to create industrial systems for enhanced collaboration between physically remote people and places – for example, factories in China with managers in Japan or the US.

Over the years I have enjoyed Mermin's colorful, idiosyncratic, and insightful papers. His interest in the foundations of quantum mechanics has led him to discover alternative explanations for various quantum mechanical puzzles and protocols. These explanations are often superior to previous explanations in both simplicity and insight, and even when they are not outright better, they provide a valuable alternative point of view. His book is filled with such explanations, and with strong, sometimes controversial, opinions on the right way of seeing something, which make his book both valuable and entertaining.

Photo libraries are growing in quantity and size, requiring better support for locating desired photographs. MediaGLOW is an interactive visual workspace designed to address this concern. It uses attributes such as visual appearance, GPS locations, user-assigned tags, and dates to filter and group photos. An automatic layout algorithm positions photos with similar attributes near each other to support users in serendipitously finding multiple relevant photos. In addition, the system can explicitly select photos similar to specified photos. We conducted a user evaluation to determine the benefit provided by similarity layout and the relative advantages offered by the different layout similarity criteria and attribute filters. Study participants had to locate photos matching probe statements. In some tasks, participants were restricted to a single layout similarity criterion and filter option. Participants used multiple attributes to filter photos. Layout by similarity without additional filters turned out to be one of the most used strategies and was especially beneficial for geographical similarity. Lastly, the relative appropriateness of the single similarity criterion to the probe significantly affected retrieval performance.

Creating virtual models of real spaces and objects is cumber- some and time consuming. This paper focuses on the prob- lem of geometric reconstruction from sparse data obtained from certain image-based modeling approaches. A number of elegant and simple-to-state problems arise concerning when the geometry can be reconstructed. We describe results and counterexamples, and list open problems.

Twitter provides a search interface to its data, along the lines of traditional search engines. But the single ranked list is a poor way to represent the richly-structured Twitter data. A more structured approach that recognizes original messages, re-tweets, people, and documents as interesting constructs is more appropriate for this kind of data. In this paper, we describe a prototype for exploring search results delivered by Twitter. The design is based on our own experience with using Twitter search, and as well as on the results of an small online questionnaire.

The use of whiteboards is pervasive across a wide range of work domains. But some of the qualities that make them successful—an intuitive interface, physical working space, and easy erasure—inherently make them poor tools for archival and reuse. If whiteboard content could be made available in times and spaces beyond those supported by the whiteboard alone, how might it be appropriated? We explore this question via ReBoard, a system that automatically captures whiteboard images and makes them accessible through a novel set of user-centered access tools. Through the lens of a seven week workplace field study, we found that by enabling new workflows, ReBoard increased the value of whiteboard content for collaboration.

The modern workplace is inherently collaborative, and this collaboration relies on effective communication among coworkers. Many communication tools – email, blogs, wikis, Twitter, etc. – have become increasingly available and accepted in workplace communications. In this paper, we report on a study of communications technologies used over a one year period in a small US corporation. We found that participants used a large number of communication tools for different purposes, and that the introduction of new tools did not impact significantly the use of previously-adopted technologies. Further, we identified distinct classes of users based on patterns of tool use. This work has implications for the design of technology in the evolving ecology of communication tools.

PACER is a gesture-based interactive paper system that supports fine-grained paper document content manipulation through the touch screen of a cameraphone. Using the phone's camera, PACER links a paper document to its digital version based on visual features. It adopts camera-based phone motion detection for embodied gestures (e.g. marquees, underlines and lassos), with which users can flexibly select and interact with document details (e.g. individual words, symbols and pixels). The touch input is incorporated to facilitate target selection at fine granularity,and to address some limitations of the embodied interaction, such as hand jitter and low input sampling rate. This hybrid interaction is coupled with other techniques such as semi-real time document tracking and loose physical-digital document registration, offering a gesture-based command system. We demonstrate the use of PACER in various scenarios including work-related reading, maps and music score playing. A preliminary user study on the design has produced encouraging user feedback, and suggested future research for better understanding of embodied vs. touch interaction and one vs. two handed interaction.

In certain applications such as radiology and imagery analysis, it is important to minimize errors. In this paper we evaluate a structured inspection method that uses eye tracking information as a feedback mechanism to the image inspector. Our two-phase method starts with a free viewing phase during which gaze data is collected. During the next phase, we either segment the image, mask previously seen areas of the image, or combine the two techniques, and repeat the search. We compare the different methods proposed for the second search phase by evaluating the inspection method using true positive and false negative rates, and subjective workload. Results show that gaze-blocked configurations reduced the subjective workload, and that gaze-blocking without segmentation showed the largest increase in true positive identifications and the largest decrease in false negative identifications of previously unseen objects.

This project investigates practical uses of virtual, mobile, and mixed reality systems in industrial settings, in particular control and collaboration applications for factories. In collaboration with TCHO, a chocolate maker start-up in San Francisco, we have built virtual mirror-world representations of a real-world chocolate factory and are importing its data and modeling its processes. The system integrates mobile devices such as cell phones and tablet computers. The resulting "virtual factory" is a cross-reality environment designed for simulation, visualization, and collaboration, using a set of interlinked, real-time 3D and 2D layers of information about the factory and its processes.