Papers.

Exact real arithmetic based on linear fractional transformations

Conversational Access to On-Line Cancer Information: An Adaptable Speech Interface

Ad Hoc Attribute-Value Prediction

AccessNova: broadband networks and multimedia services experiments.

A smooth approximation on the edge of chaos

User's Guide to MIDAS

Welcome to the MIDAS User's Guide. This document describes the goals of the Munitions Items Disposition Action System (MIDAS) program and documents the MIDAS software. The main text first describes the equipment and software you need to run MIDAS and tells how to install and start it. It lists the contents of the database and explains how it is organized. Finally, it tells how to perform various functions, such as locating, entering, viewing, deleting, changing, transferring, and printing both textual and graphical data.

Bananas in space: extending fold and unfold to exponential types

Fold and unfold are general purpose functional for processing and constructing lists. By using the categorical approach of modelling recursive dat at ypes as fixed points of funct ors, these functional and their algebraic properties were generalised from lists to polynomial (sum-of-product) datatypes. However, the restriction to polynomial datatypes is a serious limitation: it precludes the use of exponential (functionspaces ), whereas it is central to functional programming that functions are first-class values, and so exponential should be able to be used freely in datatype definitions. In this paper we explain how Freyd's work on modelling recursive datatypes as fixed points of difunctors shows how to generalise fold and unfold from polynomial datatypes to those involving exponentials. Knowledge of category theory is not required; we use Gofer throughout as our meta-language, making extensive use of constructor classes. 1

Shortcut deforestation in calculational form

In functional programming, intermediate data structures are often used to "glue" together small programs. Deforestation is a program transformation to remove these intermediate data structures automatically. We present a simple algorithm for deforestation based on two fusion rules for hylomorphism, an expressive recursion pattern. A generic notation for hylomorphisms is introduced, where natural transformations are explicitly factored out, and it is used to represent programs. Our method successfully eliminates intermediate data structures of any algebraic type from a much larger class of compositional functional programs than previous techniques. 1 Introduction In functional programming, programs are often constructed by "gluing" together small components, using intermediate data structures to convey information between them. Such data are constructed in one component and later consumed in another component, but never appear in the result of the whole program. The compositional styl...

An Ada-like separate compilation style in C

Computing in Chile

Teaching algorithms

A language for queries on structure and contents of textual databases

Fringe analysis revisited

Global code motion/global value numbering

Translation of nested APL to C++

This paper discusses the task of developing a nested APL compiler and puts forward the project of such a compiler. The proposed approach consists of simulating the semantics of APL by using the object-oriented C++ programming language. Different kinds of problems ranging from APL syntax ambiguity to the implementation of nested arrays and the robustness of compiled code are considered and different solutions are proposed. We conclude that it is feasible to develop a robust nested APL compiler, although the problem of performance demands further research.

A simple graph-based intermediate representation

We present a graph-based intermediate representation (IR) with simple semantics and a low-memory-cost C++ implementation. The IR uses a directed graph with labeled vertices and ordered inputs but unordered outputs. Vertices are labeled with opcodes, edges are unlabeled. We represent the CFG and basic blocks with the same vertex and edge structures. Each opcode is defined by a C++ class that encapsulates opcode-specific data and behavior. We use inheritance to abstract common opcode behavior, allowing new opcodes to be easily defined from old ones. The resulting IR is simple, fast and easy to use.

A modern, agent-oriented approach to introductory artificial intelligence

We describe our experiences in teaching introductory AI and in writing a textbook for the course. The book tries to make the concepts of AI more concrete via two strategies: relating them to the student's existing knowledge, and using examples based on an agent operating in an environment.

Combining analyses, combining optimizations

A call-by-need lambda calculus

The mismatch between the operational semantics of the lambda calculus and the actual behavior of implementations is a major obstacle for compiler writers. They cannot explain the behavior of their evaluator in terms of source level syntax, and they cannot easily compare distinct implementations of different lazy strategies. In this paper we derive an equational characterization of call-by-need and prove it correct with respect to the original lambda calculus. The theory is a strictly smaller theory than the lambda calculus. Immediate applications of the theory concern the correctness proofs of a number of implementation strategies, e.g., the call-by-need continuation passing transformation and the realization of sharing via assignments.

HIGHER-ORDER ANALYSIS OF 2–3 TREES

A comparative study of National ISDN versus International ISDN installations and tariffs

Impact of enhanced feature interactions

Fault-Tolerant Features in the HaL Memory Management Unit

Uncertainties of predictions in models of eternal inflation

In a previous paper \cite{MakingPredictions}, a method of comparing the volumes of thermalized regions in eternally inflating universe was introduced. In this paper, we investigate the dependence of the results obtained through that method on the choice of the time variable and factor ordering in the diffusion equation that describes the evolution of eternally inflating universes. It is shown, both analytically and numerically, that the variation of the results due to factor ordering ambiguity inherent in the model is of the same order as their variation due to the choice of the time variable. Therefore, the results are, within their accuracy, free of the spurious dependence on the time parametrization.

Business applications of ISDN

Information technology landmarks in chile: A survey

Navigating to Knowledge

Rationality and Intelligence

Parallel searching in the plane

Escaping the event loop: an alternative control structure for multi-threaded GUIs

Garbage Collection on an Open Network

Optimized binary search and text retrieval

LATIN '95: Theoretical Informatics

Stochastic simulation algorithms for dynamic probabilistic networks

Stochastic simulation algorithms such as likelihood weighting often give fast, accurate approximations to posterior probabilities in probabilistic networks, and are the methods bf choice for very large networks. Unfortunately, the special characteristics of dynamic probabilistic networks (DPNs), which are used to represent stochastic temporal processes, mean that standard simulation algorithms perform very poorly. In essence, the simulation trials diverge further and further from reality as the process is observed over time. In this paper, we present simulation algorithms that use the evidence observed at each time step to push the set of trials back towards reality. The first algorithm, "evidence reversal" (ER) restructures each time slice of the DPN so that the evidence nodes for the slice become ancestors of the state variables. The second algorithm, called "survival of the fittest" sampling (SOF), "repopulates" the set of trials at each time step using a stochastic reproduction rate weighted by the likelihood of the evidence according to each trial. We compare the performance of each algorithm with likelihood weighting on the original network, and also investigate the benefits of combining the ER and SOF methods. The ER/SOF combination appears to maintain bounded error independent of the number of time steps in the simulation.

Thinking in C++

The storage capacity of forgetful neural networks

The BATmobile: Towards a Bayesian Automated Taxi

Semantic visualization of oncology knowledge sources

Proceedings of the Second Latin American Symposium on Theoretical Informatics

Performance prediction of an image management and communication system for cardiac ultrasound

PDQ-3D: A Prototype Three Dimensional Semantic Visualizer for Oncology Knowledge Sources

Merging terminologies

MEME II: An Environment for Managing Meaning

LATIN '95: Theoretical Informatics: Second Latin American Symposium, Valparaiso, Chile, April 3 - 7, 1995. Proceedings

Knowledge Mining in Databases: An Integration of Machine Learning Methodologies with Database Technologies

Integration und Strukturierung von Expertensystemen in technischen Anwendungen (PhD dissertation)

Formal Properties of the Metathesaurus: An Update*

Explaining Your Terminology to a Computer

Dreme: for Life in the Net

Constraint-Based Scheduling System