Andreas Paepcke

Searching the Web

We offer an overview of current Web search engine design. After introducing a generic search engine architecture, we examine each engine component in turn. We cover crawling, local Web page storage, indexing, and the use of link analysis for boosting search performance. The most common design and implementation techniques for each of these components are presented. For this presentation we draw from the literature and from our own experimental search engine testbed. Emphasis is on introducing the fundamental concepts and the results of several performance analyses we conducted to compare different designs.

Time as essence for photo browsing through personal digital libraries

We developed two photo browsers for collections with thousands of time-stamped digital images. Modern digital cameras record photo shoot times, and semantically related photos tend to occur in bursts. Our browsers exploit the timing information to structure the collections and to automatically generate meaningful summaries. The browsers differ in how users navigate and view the structured collections. We conducted user studies to compare the two browsers and an un-summarized image browser. Our results show that exploiting the time dimension and appropriately summarizing collections can lead to significant improvements. For example, for one task category, one of our browsers enabled a 33% improvement in speed of finding given images compared to the commercial browser. Similarly, users were able to complete 29% more tasks when using this same browser.

Automatic organization for digital photographs with geographic coordinates

We describe PhotoCompas, a system that utilizes the time and location information embedded in digital photographs to automatically organize a personal photo collection. PhotoCompas produces browseable location and event hierarchies for the collection. These hierarchies are created using algorithms that interleave time and location to produce an organization that mimics the way people think about their photo collections. In addition, the algorithm annotates the generated hierarchy with geographical names. We tested our approach in case studies of three real-world collections and verified that the results are meaningful and useful for the collection owners.

The Stanford Digital Library Metadata Architecture

Abstract. The overall goal of the Stanford Digital Library project is to provide an infrastructure that affords interoperability among heterogeneous, autonomous digital library services. These services include both search services and remotely usable information processing facilities. In this paper, we survey and categorize the metadata required for a diverse set of Stanford Digital Library services that we have built. We then propose an extensible metadata architecture that meets these requirements. Our metadata architecture fits into our established infrastructure and promotes interoperability among existing and de-facto metadata standards. Several pieces of this architecture are implemented; others are under construction. The architecture includes attribute model proxies, attribute model translation services, metadata information facilities for search services, and local metadata repositories. In presenting and discussing the pieces of the architecture, we show how they address our motivating requirements. Together, these components provide, exchange, and describe metadata for information objects and metadata for information services. We also consider how our architecture relates to prior, relevant work on these two types of metadata.

STARTS: Stanford proposal for Internet meta-searching

Document sources are available everywhere, both within the internal networks of organizations and on the Internet. Even individual organizations use search engines from different vendors to index their internal document collections. These search engines are typically incompatible in that they support different query models and interfaces, they do not return enough information with the query results for adequate merging of the results, and finally, in that they do not export metadata about the collections that they index (e.g., to assist in resource discovery). This paper describes STARTS, an emerging protocol for Internet retrieval and search that facilitates the task of querying multiple document sources. STARTS has been developed in a unique way. It is not a standard, but a group effort coordinated by Stanfords Digital Library project, and involving over 11 companies and organizations. The objective of this paper is not only to give an overview of the STARTS protocol proposal, but also to discuss the process that led to its definition.

ButterflyNet: a mobile capture and access system for field biology research

Through a study of field biology practices, we observed that biology fieldwork generates a wealth of heterogeneous information, requiring substantial labor to coordinate and distill. To manage this data, biologists leverage a diverse set of tools, organizing their effort in paper notebooks. These observations motivated ButterflyNet, a mobile capture and access system that integrates paper notes with digital photographs captured during field research. Through ButterflyNet, the activity of leafing through a notebook expands to browsing all associated digital photos. ButterflyNet also facilitates the transfer of captured content to spreadsheets, enabling biologists to share their work. A first-use study with 14 biologists found this system to offer rich data capture and transformation, in a manner felicitous with current practice.

Context data in geo-referenced digital photo collections

Given time and location information about digital photographs we can automatically generate an abundance of related contextual metadata, using off-the-shelf and Web-based data sources. Among these are the local daylight status and weather conditions at the time and place a photo was taken. This metadata has the potential of serving as memory cues and filters when browsing photo collections, especially as these collections grow into the tens of thousands and span dozens of years. We describe the contextual metadata that we automatically assemble for a photograph, given time and location, as well as a browser interface that utilizes that metadata. We then present the results of a user study and a survey that together expose which categories of contextual metadata are most useful for recalling and finding photographs. We identify among still unavailable metadata categories those that are most promising to develop next.

Leveraging context to resolve identity in photo albums

Our system suggests likely identity labels for photographs in a personal photo collection. Instead of using face recognition techniques, the system leverages automatically available context, like the time and location where the photos were taken. Based on time and location, the system automatically computes event and location groupings of photos. As the user annotates some of the identities of people in their collection, patterns of re-occurrence and co-occurrence of different people in different locations and events emerge. The system uses these patterns to generate label suggestions for identities that were not yet annotated. These suggestions can greatly accelerate the process of manual annotation and improve the quality of retrieval from the collection. We obtained ground-truth identity annotation for four different photo albums, and used them to test our system. The system proved effective, making very accurate label suggestions, even when the number of suggestions for each photo was limited to five names, and even when only a small subset of the photos was annotated

EyePoint: practical pointing and selection using gaze and keyboard

We present a practical technique for pointing and selection using a combination of eye gaze and keyboard triggers. EyePoint uses a two-step progressive refinement process fluidly stitched together in a look-press-look-release action, which makes it possible to compensate for the accuracy limitations of the current state-of-the-art eye gaze trackers. While research in gaze-based pointing has traditionally focused on disabled users, EyePoint makes gaze-based pointing effective and simple enough for even able-bodied users to use for their everyday computing tasks. As the cost of eye gaze tracking devices decreases, it will become possible for such gaze-based techniques to be used as a viable alternative for users who choose not to use a mouse depending on their abilities, tasks and preferences.

Interoperability for digital libraries worldwide

Discusses the history and current directions of interoperability in different parts of computing systems relevant to Digital Libraries