Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

only 6% of distance traveled. Comparison with previous results of other planetary rover systems shows this to be a significant
improvement.
Author
Mars Surface; Roving Vehicles; Surface Navigation; Robots; Solar Sensors
20000064075 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA USA
Evolution of Autonomous Self-Righting Behaviors for Articulated Nanorovers
Tunstel, Edward, Jet Propulsion Lab., California Inst. of Tech., USA; [1999]; 7p; In English; No Copyright; Avail: CASI; A02,
Hardcopy; A01, Microfiche
Miniature rovers with articulated mobility mechanisms are being developed for planetary surface exploration on Mars and
small solar system bodies. These vehicles are designed to be capable of autonomous recovery from overturning during surface
operations. This paper describes a computational means of developing motion behaviors that achieve the autonomous recovery
function. It proposes a control software design approach aimed at reducing the effort involved in developing self-righting behaviors.
The approach is based on the integration of evolutionary computing with a dynamics simulation environment for evolving
and evaluating motion behaviors. The automated behavior design approach is outlined and its underlying genetic programming
infrastructure is described.
Author
Autonomy; Automatic Control; Roving Vehicles
20000065663 Los Alamos National Lab., NM USA
Enhanced lower entropy bounds with application to constructive learning
Beiu, V.; Dec. 31, 1997; 12p; In English; Computational intelligence
Report No.(s): DE97-004791; LA-UR-97-516; No Copyright; Avail: Department of Energy Information Bridge
In this paper, the authors prove two new lower bounds for the number-of-bits required by neural networks for classification
problems defined by m examples from R(sup n). Because they are obtained in a constructive way, they can be used for designing
a constructive algorithm. These results rely on techniques used for determining tight upper bounds, which start by upper bounding
the space with an n-dimensional ball. Very recently, a better upper bound has been detailed by showing that the volume of the ball
can always be replaced by the volume of the intersection of two balls. A first lower bound for the case of integer weights in the
range (-p,p) has been detailed: it is based on computing the logarithm of the quotient between the volume of the ball containing
all the examples (rough approximation) and the maximum volume of a polyhedron. A first improvement over that bound will come
from a tighter upper bound of the maximum volume of the polyhedron by two n-dimensional cones. An even tighter bound will
be obtained by upper bounding the space by the intersection of two balls.
NTIS
Entropy; Boundaries
182
65
STATISTICS AND PROBABILITY
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20000062851 Technische Univ., Dept. of Mathematics and Computing Science, Eindhoven Netherlands
Selecting the Best of Two Normal Populations Using a Loss Function
vanderLaan, P.; vanEeden, C.; Jun. 1997; 28p; In English
Report No.(s): PB2000-104939; MEMO-COSOR-97-13-Rev; No Copyright; Avail: CASI; A03, Hardcopy; A01, Microfiche
The problem of selecting the best of two normal populations is considered. In selection problems the usual loss function is
the 0-1 one, i.e. the selection goal is to bound, from below, probabilities of making ’correct’ selections. In the present paper a selection
goal based on a general loss function is presented. The two population have unknown location parameters and ’good’ populations
are the ones with large values of this parameter. The selection rule is given and its performance is investigated. An application
is presented. The selection rule is given and its performance is investigated. An application is presented. Similar results for the
scale parameters of two gamma populations can be found in Van Der Laan and Van Eeden (1996).
NTIS
Populations; Selection; Probability Theory