2,934 research outputs found
A Package of LISP Functions for Making Movies and Demos
Work reported herein was conducted at the Artificial Intelligence Laboratory, a Massachusetts Institute of Technology research program supported in part by the Advanced Research Projects Agency of the Department of Defense and monitored by the Office of Naval Research under Contract Number N00014-70-A-0362-0005.
Vision Flashes are informal papers intended for internal use.A collection of functions have been written to allow LISP users to record display calls in a disk file. This file can be UREAD into a small LISP to reproduce the display effects of the program without doing the required computations. Such a file can be regarded as a 'movie' or 'demo' file and can easily be used with the KODAK movie camera to produce a hard copy.MIT Artificial Intelligence Laboratory Robotics Sectio
The symplectic Deligne-Mumford stack associated to a stacky polytope
We discuss a symplectic counterpart of the theory of stacky fans. First, we
define a stacky polytope and construct the symplectic Deligne-Mumford stack
associated to the stacky polytope. Then we establish a relation between stacky
polytopes and stacky fans: the stack associated to a stacky polytope is
equivalent to the stack associated to a stacky fan if the stacky fan
corresponds to the stacky polytope.Comment: 20 pages; v2: To appear in Results in Mathematic
The TRACK Program Package
Work reported herein was conducted at the Artificial Intelligence Laboratory, a Massachusetts Institute of Technology research program supported in part by the Advanced Research Projects Agency of the Department of Defense and monitored by the Office of Naval Research under Contract Number N00014-70-A-0362-0005.
Vision Flashes are informal papers intended for internal use.A collection of LISP functions has been written to provide vidisector users with the following three line-oriented vision primitives:
(i) given an initial point and an estimated initial direction, track a line in that direction until the line terminates.
(ii) given two points, verify the existence of a line joining those two points.
(iii) given the location of a vertex, find suspect directions for possible lines emanating from that vertex.MIT Artificial Intelligence Laboratory Robotics Section
Department of Defense Advanced Research Projects Agenc
U.S. Forest Service and Partners Deliver Urban Wildlife Research in Support of Conservation and Management
On Non-Abelian Symplectic Cutting
We discuss symplectic cutting for Hamiltonian actions of non-Abelian compact
groups. By using a degeneration based on the Vinberg monoid we give, in good
cases, a global quotient description of a surgery construction introduced by
Woodward and Meinrenken, and show it can be interpreted in algebro-geometric
terms. A key ingredient is the `universal cut' of the cotangent bundle of the
group itself, which is identified with a moduli space of framed bundles on
chains of projective lines recently introduced by the authors.Comment: Various edits made, to appear in Transformation Groups. 28 pages, 8
figure
Intelligent Self-Repairable Web Wrappers
The amount of information available on the Web grows at an incredible high rate. Systems and procedures devised to extract these data from Web sources already exist, and different approaches and techniques have been investigated during the last years. On the one hand, reliable solutions should provide robust algorithms of Web data mining which could automatically face possible malfunctioning or failures. On the other, in literature there is a lack of solutions about the maintenance of these systems. Procedures that extract Web data may be strictly interconnected with the structure of the data source itself; thus, malfunctioning or acquisition of corrupted data could be caused, for example, by structural modifications of data sources brought by their owners. Nowadays, verification of data integrity and maintenance are mostly manually managed, in order to ensure that these systems work correctly and reliably. In this paper we propose a novel approach to create procedures able to extract data from Web sources -- the so called Web wrappers -- which can face possible malfunctioning caused by modifications of the structure of the data source, and can automatically repair themselves.\u
The Lie-Poisson structure of the reduced n-body problem
The classical n-body problem in d-dimensional space is invariant under the
Galilean symmetry group. We reduce by this symmetry group using the method of
polynomial invariants. As a result we obtain a reduced system with a
Lie-Poisson structure which is isomorphic to sp(2n-2), independently of d. The
reduction preserves the natural form of the Hamiltonian as a sum of kinetic
energy that depends on velocities only and a potential that depends on
positions only. Hence we proceed to construct a Poisson integrator for the
reduced n-body problem using a splitting method.Comment: 26 pages, 2 figure
An Analysis of Contracts for the Delivery of Managed Behavioral Health Care Services in State Correctional Facilities
This issue brief, prepared by the George Washington University Center for Health Services Research and Policy (CHSRP), presents an analysis of a sample of contractual agreements entered into by State Departments of Corrections with managed care organizations (MCOs) for the provision of managed behavioral health care services in State prisons. It is part of a series of contract studies undertaken by CHSRP that examine the implications of managed care contracting by public and private sector purchasers for the financing and delivery of behavioral health care services
Short Communications: First tracking of individual American Robins (Turdus migratorius) across seasons
The American Robin (Turdus migratorius) is one of the most widespread, common bird species in North America; yet, very little is known about its migratory connectivity, migration timing, and migratory routes. Using archival GPS tags, we tracked the movements of 7 individual robins from 3 breeding populations in the United States. Four robins captured in Denali National Park and Preserve, Alaska, overwintered in Texas, Nebraska, Oklahoma, and Montana, up to 4,500 km from the capture location. One robin captured in Amherst, Massachusetts, overwintered in South Carolina 1,210 km from the capture location, whereas 2 robins captured in Washington, D.C., spent the entire year within 6 km of their original capture location. Understanding the annual cycle and differences in migration strategies for a species that exhibits large regional variation in movement has the potential to provide novel insights into how conspecific populations respond to current and future heterogeneity in climate and habitat. The regionspecific patterns presented here suggest robins could serve as sentinels of environmental change at a continental scale
Adaptive Boolean Networks and Minority Games with Time--Dependent Capacities
In this paper we consider a network of boolean agents that compete for a
limited resource. The agents play the so called Generalized Minority Game where
the capacity level is allowed to vary externally. We study the properties of
such a system for different values of the mean connectivity of the network,
and show that the system with K=2 shows a high degree of coordination for
relatively large variations of the capacity level.Comment: 4 pages, 4 figure
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