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. This paper presents an alternative in which users are able to navigate explicitly along conceptual dimensions that describe the images. The interface makes use of hierarchical faceted metadata and dynamically generated query previews. A usability study, conducted with 32 art history students exploring 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 which often lead to rejection of new search interfaces), the study results show that 90% of the participants preferred the meta-data 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 that a category-based approach is a successful way to provide access to image collections.

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. This paper presents an alternative in which users are able to navigate explicitly along conceptual dimensions that describe the images. The interface makes use of hierarchical faceted metadata and dynamically generated query previews. A usability study, conducted with 32 art history students exploring 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 which 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 that a category-based approach is a successful way to provide access to image collections.

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

The security of any computer system that is configured and operated by human beings critically depends on the information conveyed by the user interface, the decisions of the computer users, and the interpretation of their actions. We establish some starting points for reasoning about security from a user-centred point of view, by modelling a system in terms of actors and actions and introducing the concept of the subjective actor-ability state. We identify ten key principles for user interaction design in secure systems and give case studies to illustrate and justify each principle, describing real-world problems and possible solutions. We anticipate that this work will help guide the design and evaluation of secure systems.

A touchscreen can be overlaid on a tablet computer to support asymmetric two-handed interaction in which the non-preferred hand operates the touchscreen and the preferred hand uses a stylus. 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.

The small size of handheld computers provides the convenience of mobility at the expense of reduced screen space for display and interaction. Prior research [5,6] 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 user's 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.

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.

Designers of security-sensitive software applications sometimes speak of a trade-off between achieving strong security and making software easy to use. When we look for ways to adjust an existing design, usability improvements seem to yield more easily compromised software, and adding security measures seems to make software tedious to use or hard to understand. Yet designers cannot afford to neglect either-both security and usability failures can render a product useless.Conflicts between security and usability can often be avoided by taking a different approach to security in the design process and the design itself. Every design problem involves trading off many factors, but the most successful designs find ways to achieve multiple goals simultaneously. To this end, in this article I discuss when and how we can bring security and usability into alignment through these main points:• Security and usability elements can't be sprinkled on a product like magic pixie dust. We must incorporate both goals throughout the design process. When security and usability are no longer treated as add-ons, we can design them together to avoid conflicts.• We can view security and usability as aspects of a common goal: fulfilling user expectations. This involves maintaining agreement between a system's security state and the user's mental model, both of which change over time.• An essential technique for aligning security and usability is incorporating security decisions into the users' workflow by inferring authorization from acts of designation that are already part of their primary task.I apply these points to three classes of everyday security problems: worms, cookie management, and phishing attacks. ScopeTwo assumptions frame my discussion. First, I assume a known user, setting aside the problem of authenticating the user. This article will not contribute any insights on authentication.Second, I assume that the parties we intend to serve have a mutually understood framework of acceptable behavior. (Malicious parties might attempt unacceptable behavior, but we are not interested in serving their needs.) For example, if music distributors wish to impose copying restrictions that music listeners find unreasonable, then software designers cannot serve both distributors and listeners without compromising. In such a situation, the conflict stems not from usability issues but from disagreements between people about policy, which is a different problem. Resolving such disputes is outside the scope of this discussion. Conflicts in the design processTo understand how security and usability come into conflict during software design, it might be helpful to look at this tension from both points of view. Pseudosecurity harms usabilityAs a security practitioner, you might have been asked to take a nearly complete product and make it more secure. You then know firsthand how difficult and ineffective it is to try to add on security at the last minute. Although we