Automatic Interface Generations From Grammar Specifications

This paper presents a method for automatically generating user interfaces to programs. All possible legal strings of input to a moderately interactive program, taken together, specify the input language of that program. A grammar for such a language is fundamentally knowledge about the language, and that knowledge can be used to assist the program\u27s user in constructing legal program input. The set of words which can appear next in an input sentence, the \u27Next set\u27, is defined and a technique for calculating it with a modified version of Prologs\u27s Definite Clause Grammar parser is given. One type of interface this method can generate is a menu-based front-end. The concept of menus is used very generally to include any method that allows a user to make a choice from among several options. The main difficulty with this technique is that menus may become very large (or may on occasion be infinite). This problem is overcome by the introduction of \u27pre-terminals\u27-- classes of language terminals defined by predicates. When a preterminal is chosen from a menu, the user is prompted to type a value, which is then verified against the predicate associated with the preterminal

A Graph Browser with Zoom and Roam for Allegro Common Lisp

This report describes an object-oriented tool that has been developed for viewing graphs on a Macintosh II computer using Allegro Common Lisp. The tool is useful for visualizing data which can be represented in tree or graph form. The graphs can be viewed for far away to get a global view, and from close up so that the labels on the vertices can be discerned. Scrolling can be performed at a nearly infinite number of resolutions, and a search feature makes it easy to find any node rapidly. Although the \u27information space\u27 on which the graph is logically plotted is 2-dimensional, nodes can be arbitrarily large or small, and this combined with the zooming feature gives somewhat the illusion of 3-dimensions. The tool is implemented using an object-oriented paradigm, in which the window containing the graph rendering is an object, and so are each of the vertices in the graph. Operations on vertices of the graph are implemented as messages to objects, so that specifics objects can choose to respond in individual ways to various events. This approach makes the tool useful for a wide range of tasks, including browsing the object system inheritance lattice of the lisp system itself, displaying dependency nets in a belief maintenance system, and browsing a hypertext network

The Visual Display of Temporal Information

The detection of temporal relationships among time-ordered patient data is an important, but difficult, clinical task. Large volumes of computer-stored clinical data offer the possibility of aiding in the early detection of subtle trends and states, but the presence of irrelevant data can obscure relevant findings and relationships. We present a formal system for representing complex temporal data as events on an abstract entity called a time limit. We define five time line operations, SLICE, FILTER, OVERLAY, NEW, and ADD. For each operation, we precisely define the operator\u27s effect on a time line, including exceptions and boundary conditions. IN addition to our time line, formalism, we describe an interactive environment designed specifically to help humans visualize temporal data. We have developed a database kernel and a graphical user interface that uses our time line formalism and operations to support temporal manipulations. Using our formal system and our visualization environment, we describe two issues in the display and manipulating of temporal data: (1) the temporal granularity problem, and (2) the calendar mapping problem

Towards a Generalized Database System with Multiple Interfaces

We have applied logic programming to the problem of designing knowledge representation systems. This report describes a Generalized Database System, PRODB, that has been implemented in Prolog. It also describes two extensions to the basic PRODB core. First, knowledge representation and consistency-checking features have been added to PRODB to enhance its ability to consistently represent knowledge, especially in an Engineering domain. Second, extensions to Prolog\u27s definite clause grammar mechanism have been used to create interfaces to a knowledge base directly from grammars describing the input languages. The interface to the system is derived directly from the grammars, so this part of the system is easy to tailor. In addition, we are able to use different grammars at different times in order to have multiple interfaces to the same knowledge base system

Information Retrieval from Hypertext: Update on the Dynamic Medical Handbook Project

This paper attempts to provide a perspective from which to develop a more complete theory of information retrieval from hypertext documents. Viewing hypertexts as large information spaces, we compare two general classes of navigation methods, classes we call local and global. We argue that global methods necessitate some form of “index space” conceptually separate from the hypertext “document space”. We note that the architectures of both spaces effect the ease with which one can apply various information retrieval algorithms. We identify a number of different index space and document space architectures and we discuss some of the associated trade-offs between hypertext functionality and computational complexity. We show how some index space architectures can be exploited for enhanced information retrieval, query refinement, and automated reasoning. Through analysis of a number of prototype systems, we discuss current limitations and future potentials for various hypertext information retrieval structures

The WIC Advisor: A Case Study in Medical Expert System Development

This project provides a good case study of expert system development with untrained experts over a short period of time. We describe the development of a working medical screening and diagnosis expert system for use at the Women, Infants and Children (WIC) clinics in Madison County, Illinois. The system was designed and implemented over the period of four months. A large number of knowledge acquisition techniques were employed, some of them customized in ways that greatly increased their effectiveness. This paper explores the development of THE WIC Advisor, from problem definition through expert system delivery. The knowledge acquisition methods used in creating The WIC Advisor comprise a beneficial case study of several traditional techniques. Protocol analysis, question/answer listing, knowledge acquisition room selection, prototyping, focused interviewing, multiple expert selection, direct questioning, audio-tape transcription, diving the domain, role-playing and teach back were employed [4,5]. Important factors in the success of this expert system were the selection of a limited diagnostic domain, the choice of multiple experts who worked well together, and our continuing efforts to make the experts feel comfortable with the technology and the process. The major benefits of the system include assisting clients between clinic visits, cataloging basic medical data, and providing consistent and verifiable informatio

A Psychophysical Comparison of Two Methods for Adaptive Histogram Equalization

Adaptive histogram equalization (ahe) is a method for adaptive contrast enhancement of digital images propped by Pizer et. Al.. It has the properties that it is an automatic, reproducible method for the simultaneous viewing of contrast within a digital image with a large dynamic range. Recent experiments have show that in specific cases, there is no significant difference in the ability of ahe and linear intensity windowing to display grey-scale contrast. More recently, Pizer et al. have proposed a variant of ahe which limits the allowed contrast enhancement of the image. The contrast-limited adaptive histogram equalization (clahe) produces images in which the noise content of an image is nor excessively enhanced, but in which sufficient contrast is provided for the visualization of structures within the image. Images processed with clahe have a more natural appearance and facilitate the comparison of different areas of an image. However, the reduced contrast enhancement of clahe may hinder the ability of an observer to detect the presence of some significant grey-scale contrast. In this work, a psychophysical observer experiment was performed to determine if there is a significant difference in the ability of ahe and clahe to depict grey-scale contrast. Observers were presented with CT images of the chest processed with ahe and clahe into some of which subtle artificial lesions were introduced. The observers were asked to rate their confidence regarding the presence of the lesions; this rating-scale data was analyzed using Receiver Operating Characteristic curving techniques. These ROC curves were compared for significant differences in the observers\u27 performances. In this study, no difference was found in the abilities of ahe and clahe to depict contrast information

The Display and Manipulation of Temporal Information

Because medical data have complex temporal features, special techniques are required for storing, retrieving, and displaying clinical data from electronic databases. One significant problem caused by the temporal nature of medical data has been called the temporal granularity problem. The temporal granularity problem is said to occur when the set of facts relevant to a specific problem changes as the time scale changes. We argue that what is needed to deal with changes in the relevant time scale are temporal granularity heuristics. One heuristic that we have explored is that, for any level of problem abstraction, and for each type of data item in the record, there exists an optimal level of temporal abstraction. We describe an implemented database kernel and a graphical user interface that have features designed specially to support this temporal granularity heuristic. The basis for our solution is the use of temporal abstraction and temporal granularity. This heuristic encodes the relevant behavior of each type of event at different levels of temporal granularity. In doing so, we can define a specific behavior for each type of data as the level of abstraction changes

Mojito, Anyone? An Exploration of Low-Tech Plant Water Extraction Methods for Isotopic Analysis Using Locally-Sourced Materials

The stable isotope composition of water (δ18O and δ2H) is an increasingly utilized tool to distinguish between different pools of water along the soil-plant-atmosphere continuum (SPAC) and thus provides information on how plants use water. Clear bottlenecks for the ubiquitous application of isotopic analysis across the SPAC are the relatively high-energy and specialized materials required to extract water from plant materials. Could simple and cost-effective do-it-yourself "MacGyver" methods be sufficient for extracting plant water for isotopic analysis? This study develops a suite of novel techniques for plant water extraction and compares them to a standard research-grade water extraction method. Our results show that low-tech methods using locally-sourced materials can indeed extract plant water consistently and comparably to what is done with other state-of-the-art methods. Further, our findings show that other factors play a larger role than water extraction methods in achieving the desired accuracy and precision of stable isotope composition: (1) appropriate transport, (2) fast sample processing and (3) efficient workflows. These results are methodologically promising for the rapid expansion of isotopic investigations, especially for citizen science and/or school projects or in remote areas, where improved SPAC understanding could help manage water resources to fulfill agricultural and other competing water needs