Enabling Opportunistic Navigation In Location-Based Notification Systems Scott Kelly, Ben Hood, Jason Chong Lee, Miten Sampat, Leigh Lally, D. Scott McCrickard Department of Computer Science and Center for Human Computer Interaction, Virginia Tech {smkelly, bhood, chonglee, msampat, laleigh, mccricks}@vt.edu Abstract Device-assisted navigation is rapidly becoming a major topic in computer science. PDAs and other small devices are enabling the introduction of navigational assistants to many different spaces. These areas are generally filled with points of interest with which users may choose to interact with. The natural behavior of users in such a space is to explore, interacting with objects the user deems worthy of further interaction. We call this behavior ‘opportunistic navigation.’ In this paper we define the challenges associated with and put forward several criteria for enabling opportunistic navigation in Location-Based Notification Systems. Our criteria have been implemented in the form of a prototype navigational assistant, SeeVT- ART, and have undergone a preliminary field test. 1. Introduction Device-assisted navigation is a topic that recently has become very important. Consumers are rapidly embracing GPS navigation devices. Institutions such as museums are deploying systems to aid patrons in browsing their collections of objects. As computers have become ubiquitous, present in every area of our lives, it is logical that we now look to them to aid us in getting around. As with any user-centered system, navigation systems must be designed in such a way that they assist the user in the best way possible. Of what use is a system if it does not assist you in an appropriate manner? The best way to assist a user is heavily dependent upon their task. Users of a vehicle navigation device expect the system to give them explicit, easy to follow, step-by-step directions. Their task is to get from point A to point B. It is the job of the system to facilitate this task. Another common task where users may rely on devices to assist them in their navigation is perusing a space filled with objects that are interesting to the user. Examples of such a space include museums, retail stores, and trade fairs. In all of these spaces, there are a large number of things which a user may be interested in. While some users may have exact destinations, most will have an unclear or ill- defined goal. In such a situation, the system is most useful to the user by providing information to the user so that he may decide which pieces are worth visiting or viewing. It is this scenario which will be the focus of this work. The typical behavior of people in a space filled with points of interest is one of browsing or exploring. People generally enter a space with an ill-defined goal such as “enjoy the art collection.” In the space, they will generally browse in order to find pieces that interest them. These users navigate a space by wandering around and searching for pieces that interest them. Once a piece is identified as one that is of interest to the user, generally the user will engage in some sort of interaction with the piece, such as requesting more information. We call such a method of navigating a space opportunistic navigation. Users are opportunistically moving through a space; taking advantage of any opportunities to view pieces which interest them. It is the responsibility of the designers of systems which assist in navigation to ensure that their system allows for such a behavior. Below, we present criteria designers must keep in mind when designing such systems. Many of the lessons learned and presented here have been gleaned from our experience in designing a handheld navigation system for use at the Inn at Virginia Tech. The Inn, along with the attached conference and alumni centers, has a collection of art donated by alumni on display. Or solution, dubbed SeeVT-ART, is discussed below, along with the lessons we learned and the future directions we intend to take. The biggest challenge in any device assisted navigation system is how to assist the user in navigation. The goal of the system is to provide information the user requires most at any given time. Users have many information requirements when they are navigating a space. All these information requirements are directly related to the user’s environment. Such requirements include location information, identification of surrounding points of interest, information on points of interest, etc. It is the job of the system to provide for these requirements. These requirements differ based on the task the user will be performing. If the user has a clear goal, such as getting from one point to another, the system needs to provide