Ka-Ping Yee

Faceted metadata for image search and browsing

There are currently two dominant interface types for searching and browsing large image collections: keyword-based search, and searching by overall similarity to sample images. We present an alternative based on enabling users to navigate along conceptual dimensions that describe the images. The interface makes use of hierarchical faceted metadata and dynamically generated query previews. A usability study, in which 32 art history students explored a collection of 35,000 fine arts images, compares this approach to a standard image search interface. Despite the unfamiliarity and power of the interface (attributes that often lead to rejection of new search interfaces), the study results show that 90% of the participants preferred the metadata approach overall, 97% said that it helped them learn more about the collection, 75% found it more flexible, and 72% found it easier to use than a standard baseline system. These results indicate that a category-based approach is a successful way to provide access to image collections.

Finding the flow in web site search

Designing a search system and interface may best be served (and executed) by scrutinizing usability studies.

Peephole displays: pen interaction on spatially aware handheld computers

The small size of handheld computers provides theconvenience of mobility at the expense of reduced screen space for display and interaction. Prior research has identified the value of spatially aware displays, in which a position-tracked display provides a window on a larger virtual workspace. This paper builds on that work by suggesting two-handed interaction techniques combining pen input with spatially aware displays. Enabling simultaneous navigation and manipulation yields the ability to create and edit objects larger than the screen and to drag and drop in 3-D. Four prototypes of the Peephole Display hardware were built, and several Peephole-augmented applications were written, including a drawing program, map viewer, and calendar. Multiple applications can be embedded into a personal information space anchored to the users physical reference frame. A usability study with 24 participants shows that the Peephole technique can be more effective than current methods for navigating information on handheld computers.

Animated exploration of dynamic graphs with radial layout

We describe a new animation technique for supporting interactive exploration of a graph. We use the well-known radial tree layout method, in which the view is determined by the selection of a focus node. Our main contribution is a method for animating the transition to a new layout when a new focus node is selected. In order to keep the transition easy to follow, the animation linearly interpolates the polar coordinates of the nodes, while enforcing ordering and orientation constraints. We apply this technique to visualizations of social networks and of the Gnutella file-sharing network, and discuss the results from our informal usability tests.

Two-handed interaction on a tablet display

A touchscreen can be overlaid on a tablet computer to support asymmetric two-handed interaction in which the preferred hand uses a stylus and the non-preferred hand operates the touchscreen. The result is a portable device that allows both hands to interact directly with the display, easily constructed from commonly available hardware. The method for tracking the independent motions of both hands is described. A wide variety of existing two-handed interaction techniques can be used on this platform, as well as some new ones that exploit the reconfigurability of touchscreen interfaces. Informal tests show that, when the non-preferred hand performs simple actions, users find direct manipulation on the display with both hands to be comfortable, natural, and efficient.

Polaris: virus-safe computing for Windows XP

It limits the damage a virus can do by using the operating systems own security mechanisms to enforce the Principle of Least Authority on individual applications.

Hierarchical faceted metadata in site search interfaces

One of the most pressing usability issues in the design of large web sites is that of the organization of search results. A previous study on a moderate-sized web site indicated that users understood and preferred dynamically organized faceted metadata over standard search. We are now examining how to scale this approach to very large collections, since it is difficult to present hierarchical faceted metadata in a manner appealing and understandable to general users. We have iteratively designed and tested interfaces that address these design challenges; the most recent version is receiving enthusiastic responses in ongoing usability studies.

Prerendered user interfaces for higher-assurance electronic voting

We propose an electronic voting machine architecture in which the voting user interface is prerendered and published before election day. The prerendered user interface is a verifiable artifact-an electronic sample ballot-enabling public participation in the review, verification, usability testing, and accessibility testing of the ballot. Preparing the user interface outside of the voting machine dramatically reduces the amount and difficulty of software verification required to assure the correctness of the election result. We present a design for a high-assurance touchscreen voting machine that supports a wide range of user interface styles and demonstrate its feasibility by implementing it in less than 300 lines of Python code.

SeismoSpin: a physical instrument for digital data

SeismoSpin is a novel interactive instrument that uses a Disc-Jockey-mixer analogy to give seismologists a quick and powerful way to explore Northern California earthquake data. The custom-built interface and display maps earthquake data to responsive, user-determined windows of time and geographical areas. Testers (seismologists) found that SeismoSpin provided a greater control and understanding of the dataset than current tools.

Operating an Emergency Information Service

Using the Internet to help cope with disaster.