Number of co-authors:24
Number of publications with 3 favourite co-authors:Jan Pedersen:Prabhakar Raghavan:Steve Papa:
Krishna Bharat's 3 most productive colleagues in number of publications:Scott E. Hudson:113Susan Dumais:74Ellen Isaacs:22
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Marc Hassenzahl explains the fascinating concept of User Experience and Experience Design. Commentaries by Don Norman, Eric Reiss, Mark Blythe, and Whitney Hess
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Publications by Krishna Bharat (bibliography)
Rafiei, Davood, Bharat, Krishna and Shukla, Anand (2010): Diversifying web search results. In: Proceedings of the 2010 International Conference on the World Wide Web 2010. pp. 781-790. Available online
Result diversity is a topic of great importance as more facets of queries are discovered and users expect to find their desired facets in the first page of the results. However, the underlying questions of how 'diversity' interplays with 'quality' and when preference should be given to one or both are not well-understood. In this work, we model the problem as expectation maximization and study the challenges of estimating the model parameters and reaching an equilibrium. One model parameter, for example, is correlations between pages which we estimate using textual contents of pages and click data (when available). We conduct experiments on diversifying randomly selected queries from a query log and the queries chosen from the disambiguation topics of Wikipedia. Our algorithm improves upon Google in terms of the diversity of random queries, retrieving 14% to 38% more aspects of queries in top 5, while maintaining a precision very close to Google. On a more selective set of queries that are expected to benefit from diversification, our algorithm improves upon Google in terms of precision and diversity of the results, and significantly outperforms another baseline system for result diversification.
© All rights reserved Rafiei et al. and/or their publisher
Broder, Andrei Z., Maarek, Yoelle S., Bharat, Krishna, Dumais, Susan, Papa, Steve, Pedersen, Jan and Raghavan, Prabhakar (2005): Current trends in the integration of searching and browsing. In: Proceedings of the 2005 International Conference on the World Wide Web 2005. p. 793. Available online
Searching and browsing are the two basic information discovery paradigms, since the early days of the Web. After more than ten years down the road, three schools seem to have emerged: (1) The search-centric school argues that guided navigation is superfluous since free form search has become so good and the search UI so common, that users can satisfy all their needs via simple queries (2) The taxonomy navigation school claims that users have difficulties expressing informational needs and (3) The meta-data centric school advocates the use of meta-data for narrowing large sets of results, and is successful in e-commerce where it is known as "multi faceted search". This panel brings together experts and advocates for all three schools, who will discuss these approaches and share their experiences in the field. We will ask the audience to challenge our experts with real information architecture problems.
© All rights reserved Broder et al. and/or ACM Press
Bharat, Krishna (2005): News in the age of the web. In: Proceedings of the 2005 International Conference on the World Wide Web 2005. p. 874. Available online
One of the most exciting and successful examples of the Web impacting society is online news. The history of the news industry from print to the online medium is an interesting journey. Broadcast news transformed society by making news available instantly rather than once a day. While more channels became available, barriers to entry remained high and mainstream opinions continued to dominate. News on the net has brought in a number of valuable transformations, allowing news to be made (potentially) more accessible, diverse, democratic, personalized and interactive than before. Blogging has now made "citizen reporting" possible. As with any disruptive technology online news has both positive and negative implications, such as the threat of disinformation. Computer assisted news is a fun area of research that draws upon prior work in information retrieval, data mining and user interfaces. Given the volume of online news being generated today, the ability to find news and related facts quickly and with high relevance affects both readers and journalists. The talk will address the social implications as well as the technical challenges in the dissemination of online news, with a focus on Google News. Google News is an automated service that makes over 4,500 online, English sources searchable and browseable in real time, with an emphasis on breadth of coverage.
© All rights reserved Bharat and/or ACM Press
Dom, Byron, Bharat, Krishna, Broder, Andrei, Najork, Marc, Pedersen, Jan and Tonomura, Yoshinobu (2005): How search engines shape the web. In: Proceedings of the 2005 International Conference on the World Wide Web 2005. p. 879. Available online
The state of the web today has been and continues to be greatly influenced by the existence of web-search engines. This panel will discuss the ways in which search engines have affected the web in the past and ways in which they may affect it in the future. Both positive and negative effects will be discussed as will potential measures to combat the latter. Besides the obvious ways in which search engines help people find content, other effects to be discussed include: the whole phenomenon of web-page spam, based on both text and link (e.g. link farms), the business of "Search Engine Optimization" (optimizing pages to rank highly in web-search results), the bided-terms business and the associated problem of click fraud, to name a few.
© All rights reserved Dom et al. and/or ACM Press
Bharat, Krishna and Mihaila, George A. (2002): When experts agree: using non-affiliated experts to rank popular topics. In ACM Transactions on Information Systems, 20 (1) pp. 47-58. Available online
In response to a query, a search engine returns a ranked list of documents. If the query is about a popular topic (i.e., it matches many documents), then the returned list is usually too long to view fully. Studies show that users usually look at only the top 10 to 20 results. However, we can exploit the fact that the best targets for popular topics are usually linked to by enthusiasts in the same domain. In this paper, we propose a novel ranking scheme for popular topics that places the most authoritative pages on the query topic at the top of the ranking. Our algorithm operates on a special index of "expert documents." These are a subset of the pages on the WWW identified as directories of links to non-affiliated sources on specific topics. Results are ranked based on the match between the query and relevant descriptive text for hyperlinks on expert pages pointing to a given result page. We present a prototype search engine that implements our ranking scheme and discuss its performance. With a relatively small (2.5 million page) expert index, our algorithm was able to perform comparably on popular queries with the best of the mainstream search engines.
© All rights reserved Bharat and Mihaila and/or ACM Press
Bharat, Krishna and Mihaila, George A. (2001): When experts agree: using non-affiliated experts to rank popular topics. In: Proceedings of the 2001 International Conference on the World Wide Web 2001. pp. 597-602. Available online
Bharat, Krishna, Broder, Andrei Z., Dean, Jeffrey and Henzinger, Monika Rauch (2000): A comparison of techniques to find mirrored hosts on the WWW. In JASIST - Journal of the American Society for Information Science and Technology, 51 (12) pp. 1114-1122.
Bharat, Krishna and Henzinger, Monika R. (1998): Improved Algorithms for Topic Distillation in a Hyperlinked Environment. In: Proceedings of the 21st Annual International ACM SIGIR Conference on Research and Development in Information Retrieval 1998. pp. 104-111. Available online
This paper addresses the problem of topic distillation on the World Wide Web, namely, given a typical user query to find quality documents related to the query topic. Connectivity analysis has been shown to be useful in identifying high quality pages within a topic specific graph of hyperlinked documents. The essence of our approach is to augment a previous connectivity analysis based algorithm with content analysis. We identify three problems with the existing approach and devise algorithms to tackle them. The results of a user evaluation are reported that show an improvement of precision at 10 documents by at least 45% over pure connectivity analysis.
© All rights reserved Bharat and Henzinger and/or ACM Press
Worden, Aileen, Walker, Neff, Bharat, Krishna and Hudson, Scott E. (1997): Making Computers Easier for Older Adults to Use: Area Cursors and Sticky Icons. In: Pemberton, Steven (ed.) Proceedings of the ACM CHI 97 Human Factors in Computing Systems Conference March 22-27, 1997, Atlanta, Georgia. pp. 266-271. Available online
The normal effects of aging include some decline in cognitive, perceptual, and motor abilities. This can have a negative effect on the performance of a number of tasks, including basic pointing and selection tasks common to today's graphical user interfaces. This paper describes a study of the effectiveness of two interaction techniques: area cursors and sticky icons, in improving the performance of older adults in basic selection tasks. The study described here indicates that when combined, these techniques can decrease target selection times for older adults by as much as 50% when applied to the most difficult cases (smallest selection targets). At the same time these techniques are shown not to impede performance in cases known to be problematical for related techniques (e.g., differentiation between closely spaced targets) and to provide similar but smaller benefits for younger users.
© All rights reserved Worden et al. and/or ACM Press
Marais, Hannes and Bharat, Krishna (1997): Supporting Cooperative and Personal Surfing with a Desktop Assistant. In: Robertson, George G. and Schmandt, Chris (eds.) Proceedings of the 10th annual ACM symposium on User interface software and technology October 14 - 17, 1997, Banff, Alberta, Canada. pp. 129-138. Available online
We motivate the use of desktop assistants in the context of web surfing and show how such a tool may be used to support activities in both cooperative and personal surfing. By cooperative surfing we mean surfing by a community of users who choose to cooperatively and asynchronously build up knowledge structures relevant to their group. Specifically, we describe the design of an assistant called Vistabar, which lives on the Windows desktop and operates on the currently active web browser. Vistabar instances working for individual users support the authoring of annotations and shared bookmark hierarchies, and work with profiles of community interests to make findings highly available. Thus, they support a form of community memory. Vistabar also serves as a form of personal memory by indexing pages the user sees to assist in recall. We present rationale for the assistant's design, describe roles it could play to support surfing (including those mentioned above), and suggest efficient implementation strategies where appropriate.
© All rights reserved Marais and Bharat and/or ACM Press
Bharat, Krishna and Hudson, Scott E. (1995): Supporting Distributed, Concurrent, One-Way Constraints in User Interface Applications. In: Robertson, George G. (ed.) Proceedings of the 8th annual ACM symposium on User interface and software technology November 15 - 17, 1995, Pittsburgh, Pennsylvania, United States. pp. 121-132. Available online
This paper describes Doppler a new, fast algorithm for supporting concurrent, one-way constraints between objects situated in multiple address spaces. Because of their declarative nature, convenience, low amortized cost, and good match to interface tasks, constraints have been used to support a variety of user-interface activities. Unfortunately, nearly all existing constraint maintenance algorithms are sequential in nature, and cannot function effectively in a concurrent or distributed setting. The Doppler algorithm overcomes these limitations. It is a highly efficient distributed and concurrent algorithm (based on an efficient sequential algorithm for incremental, lazy updates). Doppler relies solely on asynchronous message passing, and does not require shared memory, synchronized clocks, or a global synchronization mechanism. It supports a high degree of concurrency by efficiently tracking potential cause and effect relationships between reads and writes, and allowing all causally independent operations to execute in parallel. This makes it scalable, and optimizes reads and writes by minimizing their blocking time.
© All rights reserved Bharat and and/or ACM Press
Bharat, Krishna and Cardelli, Luca (1995): Migratory Applications. In: Robertson, George G. (ed.) Proceedings of the 8th annual ACM symposium on User interface and software technology November 15 - 17, 1995, Pittsburgh, Pennsylvania, United States. pp. 133-142. Available online
We introduce a new genre of user interface applications that can migrate from one machine to another, taking their user interface and application contexts with them, and continue from where they left off. Such applications are not tied to one user or one machine, and can roam freely over the network, rendering service to a community of users, gathering human input and interacting with people. We envisage that this will support many new agent-based collaboration metaphors. The ability to migrate executing programs has applicability to mobile computing as well. Users can have their applications travel with them, as they move from one computing environment to another. We present an elegant programming model for creating migratory applications and describe an implementation. The biggest strength of our implementation is that the details of migration are completely hidden from the application programmer; arbitrary user interface applications can be migrated by a single "migration" command. We address system issues such as robustness, persistence and memory usage, and also human factors relating to application design, the interaction metaphor and safety.
© All rights reserved Bharat and and/or ACM Press
Bharat, Krishna and Brown, Marc (1994): Building Distributed, Multi-User Applications by Direct Manipulation. In: Szekely, Pedro (ed.) Proceedings of the 7th annual ACM symposium on User interface software and technology November 02 - 04, 1994, Marina del Rey, California, United States. pp. 71-81. Available online
This paper describes Visual Obliq, a user interface development environment for constructing distributed, multi-user applications. Applications are created by designing the interface with a GUI-builder and embedding callback code in an interpreted language, in much the same way as one would build a traditional (non-distributed, single-user) application with a modern user interface development environment. The resulting application can be run from within the GUI-builder for rapid turnaround or as a stand-alone executable. The Visual Obliq runtime provides abstractions and support for issues specific to distributed computing, such as replication, sharing, communication, and session management. We believe that the abstractions provided, the simplicity of the programming model, the rapid turnaround time, and the applicability to heterogeneous environments, make Visual Obliq a viable tool for authoring distributed applications and groupware.
© All rights reserved Bharat and Brown and/or ACM Press
Bharat, Krishna and Sukaviriya, Piyawadee (1993): Animating User Interfaces Using Animation Servers. In: Hudson, Scott E., Pausch, Randy, Zanden, Brad Vander and Foley, James D. (eds.) Proceedings of the 6th annual ACM symposium on User interface software and technology 1993, Atlanta, Georgia, United States. pp. 69-79. Available online
Our approach to user interface animation involves simulating the interaction of a user with the interface by synthetically generating the input events that drive the session. The interaction is made explicit by displaying the behavior of input devices audio-visually. Such "animation" is both educational and functional, and has the potential to become a powerful new medium in the graphical user interface domain. We describe the construction of a general purpose tool for animating user interfaces -- the animation server. Clients drive the server with textual scripts that describe the interaction. These may contain constructs for obtaining application context information at runtime and synchronizing with other media servers. We present a few potential applications for animation servers, including a groupware package for loosely coupled collaboration.
© All rights reserved Bharat and Sukaviriya and/or ACM Press
Sukaviriya, Piyawadee, Isaacs, Ellen and Bharat, Krishna (1992): Multimedia Help: A Prototype and an Experiment. In: Bauersfeld, Penny, Bennett, John and Lynch, Gene (eds.) Proceedings of the ACM CHI 92 Human Factors in Computing Systems Conference June 3-7, 1992, Monterey, California. pp. 433-434. Available online
On-line help systems have not paralleled recent advances in user interface technology. In particular, traditional textual help does not support visualization of the interaction processes needed to complete tasks, especially in graphical interfaces. In this demonstration, we present an experimental prototype which is capable of presenting help information in text, audio, static graphics, video, and context-sensitive animation. The prototype is used in a study on how multimedia technology enhances user performance.
© All rights reserved Sukaviriya et al. and/or ACM Press
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