NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Algorithms for Learning Preferences for Sets of ObjectsA method is being developed that provides for an artificial-intelligence system to learn a user's preferences for sets of objects and to thereafter automatically select subsets of objects according to those preferences. The method was originally intended to enable automated selection, from among large sets of images acquired by instruments aboard spacecraft, of image subsets considered to be scientifically valuable enough to justify use of limited communication resources for transmission to Earth. The method is also applicable to other sets of objects: examples of sets of objects considered in the development of the method include food menus, radio-station music playlists, and assortments of colored blocks for creating mosaics. The method does not require the user to perform the often-difficult task of quantitatively specifying preferences; instead, the user provides examples of preferred sets of objects. This method goes beyond related prior artificial-intelligence methods for learning which individual items are preferred by the user: this method supports a concept of setbased preferences, which include not only preferences for individual items but also preferences regarding types and degrees of diversity of items in a set. Consideration of diversity in this method involves recognition that members of a set may interact with each other in the sense that when considered together, they may be regarded as being complementary, redundant, or incompatible to various degrees. The effects of such interactions are loosely summarized in the term portfolio effect. The learning method relies on a preference representation language, denoted DD-PREF, to express set-based preferences. In DD-PREF, a preference is represented by a tuple that includes quality (depth) functions to estimate how desired a specific value is, weights for each feature preference, the desired diversity of feature values, and the relative importance of diversity versus depth. The system applies statistical concepts to estimate quantitative measures of the user s preferences from training examples (preferred subsets) specified by the user. Once preferences have been learned, the system uses those preferences to select preferred subsets from new sets. The method was found to be viable when tested in computational experiments on menus, music playlists, and rover images. Contemplated future development efforts include further tests on more diverse sets and development of a sub-method for (a) estimating the parameter that represents the relative importance of diversity versus depth, and (b) incorporating background knowledge about the nature of quality functions, which are special functions that specify depth preferences for features.
Document ID
20100024414
Acquisition Source
Jet Propulsion Laboratory
Document Type
Other - NASA Tech Brief
Authors
Wagstaff, Kiri L.
(California Inst. of Tech. Pasadena, CA, United States)
desJardins, Marie
(Maryland Univ. Baltimore County MD, United States)
Eaton, Eric
(Maryland Univ. Baltimore County MD, United States)
Date Acquired
August 24, 2013
Publication Date
July 1, 2010
Publication Information
Publication: NASA Tech Briefs, July 2010
Subject Category
Man/System Technology And Life Support
Report/Patent Number
NPO-43828
Report Number: NPO-43828
Distribution Limits
Public
Copyright
Public Use Permitted.
No Preview Available