Engineering topics

Chien, S.

Publications and source records attributed to Chien, S..

115 records · Page 7

NASA NTRS1994

Constructing Simplified Plans via Truth Criteria Approximation

This paper has presented an approach to dealing with the complexity of explanation-based learning plans in complex domains. This approach uses a simplified algorithm to construct plans, and employs later refinements to repair bugs in constructed plans. This algorithm has the theoretical properties of completeness and convergence upon soundness. This incremental reasoning planning and learning algorithm has been implemented using a partial-order constraint posting planner and empirically compared to a conventional exhaustive reasoning partial-order constraint-posting planner and learning algorithm. This comparison showed that 1) incremental reasoning significantly reduced learning costs compared to exhaustive reasoning, 2) Explanation-based Learning (EBL) reduced failures from incremental reasoning, 3) EBL with incremental reasoning required less search to solve problems than EBL with exhaustive reasoning.

Explanation-based learning EBL incremental reasoni↗

NASA NTRS1994

Producing Satisfactory Solutions to Scheduling Problems: An Iterative Constraint Relaxation Approach

One drawback to using constraint-propagation in planning and scheduling systems is that when a problem has an unsatisfiable set of constraints such algorithms typically only show that no solution exists. While, technically correct, in practical situations, it is desirable in these cases to produce a satisficing solution that satisfies the most important constraints (typically defined in terms of maximizing a utility function). This paper describes an iterative constraint relaxation approach in which the scheduler uses heuristics to progressively relax problem constraints until the problem becomes satisfiable. We present empirical results of applying these techniques to the problem of scheduling spacecraft communications for JPL/NASA antenna resources.

Constraint Satisfaction Problems CSP constraint pr↗

NASA NTRS1994

A Statistical Approach to Adaptive Problem-Solving for Large-Scale Scheduling and Resource Allocation Problems

Our work focuses upon development of techniques for choosing among a set of alternatives in the presence of incomplete information and varying costs of acquiring information.

alternatives↗

NASA NTRS1994

Deciding When and How to Learn

Learning is an important aspect of intelligent behavior. Unfortunately, learning rarely comes for free.

machine learning powerful learning approaches comp↗

NASA NTRS1994

On the Efficient Allocation of Resources for Hypothesis Evaluation: A Statistical Approach

This paper considers the decision-making problem of selecting a strategy from a set of alternatives on the basis of incomplete information (e.g., a finite number of observation). At any time the system can adopt a particular strategy or decide to gather additional information at some cost.

machine learning↗

NASA NTRS1994

On the Efficient Allocation of Resources for Hypothesis Evaluation in Machine Learning: A Statistical Approach

In this report we consider a decision-making problem of selecting a strategy from a set of alternatives on the basis of incomplete information (e.g., a finite number of observations): the system can, however, gather additional information at some cost.

machine learning↗

NASA NTRS1965

Viscosity of blood at low shear rates - Observations on its relation to volume concentration and size of the red cells

Viscosity of blood at low shear rates and its relation to volume concentration and size of red cells

VOLUME↗