Layout refers to the process of determining the size and position of the visual objects in an information presentation. We introduce the WeightMap, a bitmap representation of the visual weight of a presentation. In addition, we present algorithms that use WeightMaps to allow an automated layout system to evaluate the effectiveness of its layouts. Our approach is based on the concepts of visual weight and visual balance, which are fundamental to the visual arts. The objects in the layout are each assigned a visual weight, and a WeightMap is created that encodes the visual weight of the layout. Image-processing techniques, including pyramids and edge detection, are then used to efficiently analyze the WeightMap for balance. In addition, derivatives of the sums of the rows and columns are used to generate suggestions for how to improve the layout.

We describe an automated layout system called AIL that generates the user interface for the PERSIVAL digital library project. AIL creates a layout based on a variety of content components and associated meta-data information provided by the PERSIVAL generation and retrieval modules. By leveraging semantic links between the content components, the layout that AIL provides is both context and user-model aware. In addition, AIL is capable of interacting intelligently with the natural language generation components of PERSIVAL to tailor the length of the text content for a given layout.

Network and server-centric computing paradigms are quickly returning to being the dominant methods by which we use computers. Web applications are so prevalent that the role of a PC today has been largely reduced to a terminal for running a client or viewer such as a Web browser. Implementers of network-centric applications typically rely on the limited capabilities of HTML, employing proprietary "plug ins" or transmitting the binary image of an entire application that will be executed on the client. Alternatively, implementers can develop without regard for remote use, requiring users who wish to run such applications on a remote server to rely on a system that creates a virtual frame buffer on the server, and transmits a copy of its raster image to the local client.We review some of the problems that these current approaches pose, and show how they can be solved by developing a distributed user interface toolkit. A distributed user interface toolkit applies techniques to the high level components of a toolkit that are similar to those used at a low level in the X Window System. As an example of this approach, we present RemoteJFC, a working distributed user interface toolkit that makes it possible to develop thin-client applications using a distributed version of the Java Foundation Classes.

Conventional video cameras have limited fields of view which make them restrictive in a variety of applications. A catadioptric sensor uses a combination of lenses and mirrors placed in a carefully arranged configuration to capture a much wider field of view. At Columbia University, we have developed a wide range of catadioptric sensors. Some of these sensors have been designed to produce unusually large fields of view. Others have been constructed for the purpose of depth computation. All our sensors perform in real time using just a PC.