730 research outputs found
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A summary of machine learning papers from IJCAI-85
This report reviews the 31 papers on machine learning that were presented at the Ninth International Joint Conference on Artificial Intelligence (IJCAI-85) held in Los Angeles during August, 1985. The papers are grouped according to a taxonomy of the various subareas of machine learning research. The areas receiving the most attention at IJCAI-85 included learning apprentice systems and methods of explanation-based learning, although virtually all areas of machine learning research were represented. The paper describes some opportunities for further research, especially in the area of discovering new terms. The wide variety and high quality of the papers demonstrates that machine learning is a very healthy field of research
NASA space station automation: AI-based technology review
Research and Development projects in automation for the Space Station are discussed. Artificial Intelligence (AI) based automation technologies are planned to enhance crew safety through reduced need for EVA, increase crew productivity through the reduction of routine operations, increase space station autonomy, and augment space station capability through the use of teleoperation and robotics. AI technology will also be developed for the servicing of satellites at the Space Station, system monitoring and diagnosis, space manufacturing, and the assembly of large space structures
Generating Programming Environments with Integrated Text and Graphics for VLSI Design Systems
The constant improvements in device integration, the development of new technologies
and the emergence of new design techniques call for flexible, maintainable
and robust software tools. The generic nature of compiler-compiler systems,
with their semi-formal specifications, can help in the construction of those tools.
This thesis describes the Wright editor generator which is used in the synthesis
of language-based graphical editors (LBGEs). An LBGE is a programming
environment where the programs being manipulated denote pictures. Editing
actions can be specified through both textual and graphical interfaces. Editors
generated by the Wright system are specified using the formalism of attribute
grammars.
The major example editor in this thesis, Stick-Wright, is a design entry system
for the construction of VLSI circuits. Stick-Wright is a hierarchical symbolic
layout editor which exploits a combination of text and graphics in an interactive
environment to provide the circuit designer with a tool for experimenting with
circuit topologies. A simpler system, Pict-Wright: a picture drawing system, is
also used to illustrate the attribute grammar specification process.
This thesis aims to demonstrate the efficacy of formal specification in the
generation of software-tools. The generated system Stick-Wright shows that a
text/graphic programming environment can form the basis of a powerful VLSI
design tool, especially with regard to providing the designer with immediate
graphical feedback. Further applications of the LBGE generator approach to
system design are given for a range of VLSI design activities
Towards Understanding and Harnessing the Potential of Clause Learning
Efficient implementations of DPLL with the addition of clause learning are
the fastest complete Boolean satisfiability solvers and can handle many
significant real-world problems, such as verification, planning and design.
Despite its importance, little is known of the ultimate strengths and
limitations of the technique. This paper presents the first precise
characterization of clause learning as a proof system (CL), and begins the task
of understanding its power by relating it to the well-studied resolution proof
system. In particular, we show that with a new learning scheme, CL can provide
exponentially shorter proofs than many proper refinements of general resolution
(RES) satisfying a natural property. These include regular and Davis-Putnam
resolution, which are already known to be much stronger than ordinary DPLL. We
also show that a slight variant of CL with unlimited restarts is as powerful as
RES itself. Translating these analytical results to practice, however, presents
a challenge because of the nondeterministic nature of clause learning
algorithms. We propose a novel way of exploiting the underlying problem
structure, in the form of a high level problem description such as a graph or
PDDL specification, to guide clause learning algorithms toward faster
solutions. We show that this leads to exponential speed-ups on grid and
randomized pebbling problems, as well as substantial improvements on certain
ordering formulas
Considerations for a design and operations knowledge support system for Space Station Freedom
Engineering and operations of modern engineered systems depend critically upon detailed design and operations knowledge that is accurate and authoritative. A design and operations knowledge support system (DOKSS) is a modern computer-based information system providing knowledge about the creation, evolution, and growth of an engineered system. The purpose of a DOKSS is to provide convenient and effective access to this multifaceted information. The complexity of Space Station Freedom's (SSF's) systems, elements, interfaces, and organizations makes convenient access to design knowledge especially important, when compared to simpler systems. The life cycle length, being 30 or more years, adds a new dimension to space operations, maintenance, and evolution. Provided here is a review and discussion of design knowledge support systems to be delivered and operated as a critical part of the engineered system. A concept of a DOKSS for Space Station Freedom (SSF) is presented. This is followed by a detailed discussion of a DOKSS for the Lyndon B. Johnson Space Center and Work Package-2 portions of SSF
Workshop on Fuzzy Control Systems and Space Station Applications
The Workshop on Fuzzy Control Systems and Space Station Applications was held on 14-15 Nov. 1990. The workshop was co-sponsored by McDonnell Douglas Space Systems Company and NASA Ames Research Center. Proceedings of the workshop are presented
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Selecting appropriate representations for learning from examples
The task of inductive learning from examples places constraints on the representation of training instances and concepts. These constraints are different from, and often incompatible with, the constraints placed on the representation by the performance task. This incompatibility explains why previous researchers have found it so difficult to construct good representations for inductive learning-they were trying to achieve a compromise between these two sets of constraints. To address this problem, we have developed a learning system that employs two different representations: one for learning and one for performance. The learning system accepts training instances in the "performance representation," converts them into a "learning representation" where they are inductively generalized, and then maps the learned concept back into the "performance representation." The advantages of this approach are (a) many fewer training instances are required to learn the concept, (b) the biases of the learning program are very simple, and ( c) the learning system requires virtually no "vocabulary engineering" to learn concepts in a new domain
On Spike-Timing-Dependent-Plasticity, Memristive Devices, and Building a Self-Learning Visual Cortex
In this paper we present a very exciting overlap between emergent nanotechnology and neuroscience, which has been discovered by neuromorphic engineers. Specifically, we are linking one type of memristor nanotechnology devices to the biological synaptic update rule known as spike-time-dependent-plasticity (STDP) found in real biological synapses. Understanding this link allows neuromorphic engineers to develop circuit architectures that use this type of memristors to artificially emulate parts of the visual cortex. We focus on the type of memristors referred to as voltage or flux driven memristors and focus our discussions on a behavioral macro-model for such devices. The implementations result in fully asynchronous architectures with neurons sending their action potentials not only forward but also backward. One critical aspect is to use neurons that generate spikes of specific shapes. We will see how by changing the shapes of the neuron action potential spikes we can tune and manipulate the STDP learning rules for both excitatory and inhibitory synapses. We will see how neurons and memristors can be interconnected to achieve large scale spiking learning systems, that follow a type of multiplicative STDP learning rule. We will briefly extend the architectures to use three-terminal transistors with similar memristive behavior. We will illustrate how a V1 visual cortex layer can assembled and how it is capable of learning to extract orientations from visual data coming from a real artificial CMOS spiking retina observing real life scenes. Finally, we will discuss limitations of currently available memristors. The results presented are based on behavioral simulations and do not take into account non-idealities of devices and interconnects. The aim of this paper is to present, in a tutorial manner, an initial framework for the possible development of fully asynchronous STDP learning neuromorphic architectures exploiting two or three-terminal memristive type devices. All files used for the simulations are made available through the journal web site1
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