Steven J. Harrington

Aesthetic measures for automated document layout

A measure of aesthetics that has been used in automated layout is described. The approach combines heuristic measures of attributes that degrade the aesthetic quality. The combination is nonlinear so that one bad aesthetic feature can harm the overall score. Example heuristic measures are described for the features of alignment regularity separation balance white-space fraction white-space free flow proportion uniformity and page security.

Creating personalized documents: an optimization approach

The digital networked world is enabling and requiring a new emphasis on personalized document creation. The new, more dynamic digital environment demands tools that can reproduce both the contents and the layout automatically, tailored to personal needs and transformed for the presentation device, and can enable novices to easily create such documents. In order to achieve such automated document assembly and transformation, we have formalized custom document creation as a multiobjective optimization problem, and use a genetic algorithm to assemble and transform compound personalized documents. While we have found that such an automated process for document creation opens new possibilities and new workflows, we have also found several areas where further research would enable the approach to be more broadly and practically applied. This paper reviews the current system and outlines several areas where future research will broaden its current capabilities.

Designing File Replication Schemes for Peer-to-Peer File Sharing Systems

Peer-to-peer (P2P) file sharing systems are becoming increasingly popular due to their flexibility and scalability. We propose a new model to design file replication schemes for P2P file sharing systems. The model introduces expected costs for serving user requests for the files which are computed from node up/down statistics. Based on the model we introduce and develop several methods to determine the sets of nodes to store copies of the files in order to optimize certain performance metrics (e.g., maximize the system hit rate, minimize the total expected cost). We verify the effectiveness of the file replication schemes via simulation. We also outline a framework to implement the file replication schemes for P2P file sharing systems in a distributed and adaptive manner. The framework scales to a large number of nodes and files and can handle user request pattern change via file migration.

Improved algorithmic mapping of color to texture

Several improved algorithms to map color information to color or black texture are introduced. The new algorithms are based on pattern mixing and halftoning. The detailed algorithms are described along with the comparative analysis of their implementation. The analysis and the experiment result show that the halftone based algorithms described in this paper have advantages over the pattern mixing algorithm.

A system for the identification of multi-page Web documents

When a World Wide Web (WWW) document spans multiple Web pages, it is often inconvenient to print or download the entire document using available tools. A two-phase iterative approach has been developed for the automated identification of pages residing within the same document boundary, given a starting uniform resource locator (URL) as input. This system was applied to a test suite of 98 Web documents, and the results were compared to a ground truth document boundary in each case. Using a set intersection metric, an overall success rate of 73 % was achieved. This is a significant improvement over existing tools, which are not fully automated, and can achieve a success rate of only 61 % with user assistance.

Semi-vector error diffusion for color images

Color error diffusion can be classified into two types, namely, vector error diffusion and scalar error diffusion, according to the underlying quantization methods. Compared to scalar error diffusion, vector error diffusion is superior in image quality. However, it requires significantly more computation, and can introduce artifacts due to accumulation of the errors in output device space. In this paper, we propose a new quantization algorithm for CMY color error diffusion. The algorithm, which we call semi- vector quantization, has a low computational complexity and a high stability as similar to scalar error diffusion, but yields superb quality images close to those generated from vector error diffusion.

Color mixing models

In black-and-white printing the page image can be represented within a computer as an array of binary values indicating whether or not pixels should be inked. The Boolean operators of AND, OR, and EXCLUSIVE-OR are often used when adding new objects to the image array. For color printing the page may be represented as an array of continuous tone color values, and the generalization of these logic functions to gray-scale or full-color images is, in general, not defined or understood. When incrementally composing a page image new colors can replace old in an image buffer, or new colors and old can be combined according to some mixing function to form a composite color which is stored. This paper examines the properties of the Boolean operations and suggests full-color mixing functions which preserve the desired properties. These functions can be used to combine colored images, giving various transparency effects. The relationships between the mixing functions and physical models of color mixing are also discussed.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Two-dimensional vector field visualization by halftoning

Digital halftoning is a technique for converting an image with multiple levels of grey into a bi-level (bitmap) image, typically in preparation for printing on paper. It is standard practice to “optimize” the halftoning process to reduce the visibility of artifacts that appear as textures within what should be a region of uniform or slowly varying intensity. This paper describes a method of manipulating the halftoning process to cause the texture to give an indication of field direction, while the field magnitude is displayed using the intensity.

Navigating web search results

Web searches for a specific topic can result in multiple document references for the topic, where information on the topic is redundantly presented across the document set. This can make it difficult for the user to locate a unique piece of information from the document set, or to comprehend the full scope of the information, without examining one document after another in the hope of discovering that new or interesting fact. Summarization techniques reduce the redundancy but often at the cost of information loss. Aggregation is difficult and may present information out of context. This paper presents a method for navigating the document set such that the facts or concepts and their redundant presentations are identified. The user can gain an overview of the concepts, and can locate where they are presented. The user can then view a desired concept as presented in the context of the document of choice. The approach also allows the user to move from concept to concept apart from the sequence of any one particular document. Navigation is accomplished via a graph structure in which redundant material is grouped into nodes. Sequential material unique to a document can also be clustered into a node for a more compact graph representation. Methods for identification of redundant content and for the construction of the navigation graph are discussed.

Presentation of structured documents without a style sheet

In order to present most XML documents for human consumption, formatting information must be introduced and applied. Formatting is typically done through a style sheet, however, it is conceivable that one could wish to view the document without having a style sheet (either because a style sheet does not exist, or is unavailable, or is inappropriate for the display device). This paper describes a method for formatting structured documents without a provided style sheet. The idea is to first analyze the document to determine structures and features that might be relevant to style decisions. A transformation can be constructed to convert the original document to a generic form that captures the semantics that will be expressed through formatting and style. In the second stage styling is applied to the structures and features that have been discovered by applying a pre-defined style sheet for the generic form. The document instance, and if available, the corresponding schema or DTD can be analyzed in order to construct the transformation. This paper will describe the generic form used for formatting and techniques for generating transformations to it.